Microplastics(MPs)pollution has emerged as a critical global environmental issue,for which rivers serve as key conduits for the transport of MPs from land to ocean.There remained a lack of clarity regarding the charac...Microplastics(MPs)pollution has emerged as a critical global environmental issue,for which rivers serve as key conduits for the transport of MPs from land to ocean.There remained a lack of clarity regarding the characteristics and transport patterns of MPs pollution in diverse environmental media and seasons within a river basin.The Jiulong River basin in Fujian,southeast China was studied as case,whose spatial-temporal distribution,pollution characteristics,and transport dynamics of MPs in both surface water and groundwater were analyzed.Additionally,the features of MPs in different land use types during the dry season were examined.Results show that in wet season,the abundance of MPs in river water varied from 840 to 12300 p/m^(3),with an average of 3920 p/m^(3);in groundwater,the range was 740-1820 p/m^(3),averaging 1107 p/m^(3);and from 68 to 951 p/kg,with an average value of 265 p/kg in the soil(dry weight).In dry season,levels of MPs in river water ranged from 580 to 8880 p/m^(3),with an average of 4034 p/m^(3);groundwater exhibited a range of 860-14980 p/m^(3),averaging 3453 p/m^(3).Fibers consistently dominated the morphology of MPs,of which polyethylene terephthalate was identified as the predominant composition in each environmental medium.Our findings underscore the spatial and temporal variability in distribution and contamination characteristics of MPs across different media.Notably,MPs abundance in river water and groundwater exhibited a seasonal pattern,being higher in levels in dry season than in wet season.The downstream transport of MPs was facilitated by surface runoff,in which MPs in groundwater and surface water could complement to each other.Furthermore,population density and human activities were identified as influential factors on the distribution and abundance of MPs.This study revealed the order of magnitude of difference in annual estimates of MPs entering the sea among different models.Additionally,the interception volume by mangrove forest in the Jiulong River estuary was estimated approximately 1.51×10^(10)MPs particles per year.Ecological interception shall be considered when estimating the fluxes of MPs into the sea.展开更多
Highly evolved granite is an important sign of the mature continent crust and closely associated with deposits of rare metals.In this work,the authors undertake systematically zircon U-Pb ages and whole rock elemental...Highly evolved granite is an important sign of the mature continent crust and closely associated with deposits of rare metals.In this work,the authors undertake systematically zircon U-Pb ages and whole rock elemental data for highly evolved granitic intrusions from the Great Xing’an Range(GXR),NE China,to elucidate their discriminant criteria,spatial-temporal distribution,differentiation and geodynamic mecha-nism.Geochemical data of these highly evolved granites suggest that high w(SiO_(2))(>70%)and differentiation index(DI>88)could be quantified indicators,while strong Eu depletion,high TE_(1,3),lowΣREE and low Zr/Hf,Nb/Ta,K/Rb could only be qualitative indicators.Zircon U-Pb ages suggest that the highly evolved gran-ites in the GXR were mainly formed in Late Mesozoic,which can be divided into two major stages:Late Ju-rassic-early Early Cretaceous(162-136 Ma,peak at 138 Ma),and late Early Cretaceous(136-106 Ma,peak at 126 Ma).The highly evolved granites are mainly distributed in the central-southern GXR,and display a weakly trend of getting younger from northwest to southeast,meanwhile indicating the metallogenic potential of rare metals within the central GXR.The spatial-temporal distribution,combined with regional geological data,indicates the highly evolved Mesozoic granites in the GXR were emplaced in an extensional environ-ment,of which the Late Jurassic-early Early Cretaceous extension was related to the closure of the Mongol-Okhotsk Ocean and roll-back of the Paleo-Pacific Plate,while the late Early Cretaceous extension was mainly related to the roll-back of the Paleo-Pacific Plate.展开更多
[Objective] This paper aimed to understand the area change and distribu- tion of medium-low yield farmland, and offered basis to the improvement of mediumlow farmland and its increase of grain production in Tianjin. [...[Objective] This paper aimed to understand the area change and distribu- tion of medium-low yield farmland, and offered basis to the improvement of mediumlow farmland and its increase of grain production in Tianjin. [Method] Based on the statistical date of Tianjin and its relevant counties and districts, the yield standard was set up to classify high-yield, medium-yield and low-yield farmland in Tianjin. The author analyzed area change of medium-low yield farmland in six agricultural counties and districts （including Jixian County, Wuqing District, Baodi District, Ninghe County, Jinghai County and Dagang district of Binghai New Area） from 1980 to 2010. [Result] The results showed that the average yield of grain rose from 2 445 kg/hm^2 in 1980 to 5 130 kg/hm^2 in 2010, increasing 109.82%. The area of mediumlow yield farmland was reduced from 291 250.13 hm^2 in 1985 to 76 489.87 hm^2 in 2010, coming down 74%. In Tianjin, the area of medium-low yield farmland of 2010 accounted for 19% of the total farmland, of which the ratios of medium-low yield farmland of Jinghai County, Jixian County, Dagang district of Binghai New Area, Wuqing District, Baodi District and Ninghe County were 43.12%, 18.59%, 17.23%, 14.01%, 7.05% and 0, respectively. Low soil nutrient content, drought and water shortage, as well as soil salinization were the main yield limiting factors to mediumlow yield farmland in Tianjin in 2010. [Conclusion] The countermeasures to improve the medium-low yield farmland were proposed, involving enhancing the investment of the government, strengthening the construction of water conservancy infrastructure, further improving the soil fertility, as well as saline and alkaline land, optimizing the farming system and planting drought and salt tolerance crops, etc.展开更多
Dykes are a special kind of intrusive rocks which were formed by deep magma intruded into the existing brittle fractures in the crust.Dykes swarms in different tectonic environments are very significant to re-construc...Dykes are a special kind of intrusive rocks which were formed by deep magma intruded into the existing brittle fractures in the crust.Dykes swarms in different tectonic environments are very significant to re-construct the展开更多
1 Introduction Geochemical mapping at national and continental scales continues to present challenges worldwide due to variations in geologic and geotectonic units.Use of the proper sampling media can provide rich inf...1 Introduction Geochemical mapping at national and continental scales continues to present challenges worldwide due to variations in geologic and geotectonic units.Use of the proper sampling media can provide rich information on展开更多
Grain composition plays a vital role in impact pressure of debris flow. Current approaches treat debris flow as uniform fluid and almost ignore its granular effects. A series of flume experiments have been carried out...Grain composition plays a vital role in impact pressure of debris flow. Current approaches treat debris flow as uniform fluid and almost ignore its granular effects. A series of flume experiments have been carried out to explore the granular influence on the impact process of debris flow by using a contact surface pressure gauge sensor(Tactilus~?, produced by Sensor Products LLC). It is found that the maximum impact pressure for debris flow of low density fluctuates drastically with a long duration time while the fluctuation for flow of high density is short in time, respectively presenting logarithmic and linear form in longitudinal attenuation. This can be ascribed to the turbulence effect in the former and grain collisions and grainfluid interaction in the latter. The horizontal distribution of the impact pressure can be considered as the equivalent distribution. For engineering purposes, the longitudinal distribution of the pressure can be generalized to a triangular distribution, from which a new impact method considering granular effects is proposed.展开更多
The variation of the atmospheric Carbon Dioxide （CO2） concentration plays an important role in global cli- mate and agriculture. We analyzed the spatial-temporal characteristics of CO2 in the China region and around...The variation of the atmospheric Carbon Dioxide （CO2） concentration plays an important role in global cli- mate and agriculture. We analyzed the spatial-temporal characteristics of CO2 in the China region and around the globe with the CO2 column mixing ratios observed by the Japanese GOSAT satellite （Greenhouse Gases Observing Satellite）. In order to make sure that the accuracy of the CO2 data retrieved by the satellite meets the needs of the climate charac- teristics analyses, we ran a validation on the CO2 column mixing ratios retrieved by the satellite against the ground-based TCCON （Total Carbon Column Observing Network） observation data. The result shows that the two sets of data have a correlation coefficient of higher than 0.7, and a bias of within 2.2 ppmv. Therefore, the GOSAT CO2 da- ta can be used for the climate characteristics analysis of global CO2. Our analysis on the spatial-temporal characteristics of the CO2 column mixing ratios observed during the period of June 2009 through January 2014 proved that, with the impact of the natural emission of near ground CO2 and human activities, the global CO2 concentration has a significant latitudinal characteristics with its highest level averaging 390 oomv in the 0-40？N latitudinal zone in the Northern Hemisphere, and 387 ppmv in the Southern Hemisphere. China has a relatively higher CO2 concentration with the highest level exceeding 398 ppmv, and the eastern area higher than the western area. The variation of global CO2 concentration shows a seasonal pattern, i.e. the CO2 concen- tration reaches its highest in spring in the Northern Hemisphere averaging more than 392 ppmv, second highest in win- ter, and lowest in summer averaging less than 387 ppmv. It fluctuates the most in the Northern Hemisphere with an av- erage concentration of 392.5 ppmv in April, and 385.5 ppmv in July. While in the Southern Hemisphere, the seasonal fluctuation is smaller with the highest concentration occurring in July. Over the recent years, the global CO2 concentra- tion has shown an elevating trend with an average annual increase rate of 1.58 ppmv per year. It is a challenge that the human kind has to face to slow down the increase of the CO2 concentration.展开更多
Earthquakes exhibit clear clustering on the earth. It is important to explore the spatial-temporal characteristics of seismicity clusters and their spatial heterogeneity. We analyze effects of plate space, tectonic st...Earthquakes exhibit clear clustering on the earth. It is important to explore the spatial-temporal characteristics of seismicity clusters and their spatial heterogeneity. We analyze effects of plate space, tectonic style, and their interaction on characteristic of cluster.Based on data of earthquakes not less than moment magnitude(M_w) 5.6 from 1960 to 2014, this study used the spatial-temporal scan method to identify earthquake clusters. The results indicate that seismic spatial-temporal clusters can be classified into two types based on duration: persistent clusters and burst clusters. Finally, we analysed the spatial heterogeneity of the two types. The main conclusions are as follows: 1) Ninety percent of the persistent clusters last for 22-38 yr and show a high clustering likelihood;ninety percent of the burst clusters last for 1-1.78 yr and show a high relative risk. 2) The persistent clusters are mainly distributed in interplate zones, especially along the western margin of the Pacific Ocean. The burst clusters are distributed in both intraplate and interplate zones, slightly concentrated in the India-Eurasia interaction zone. 3) For the persistent type, plate interaction plays an important role in the distribution of the clusters’ likelihood and relative risk. In addition, the tectonic style further enhances the spatial heterogeneity. 4) For the burst type,neither plate activity nor tectonic style has an obvious effect on the distribution of the clusters’ likelihood and relative risk. Nevertheless,interaction between these two spatial factors enhances the spatial heterogeneity, especially in terms of relative risk.展开更多
Rare metals including Lithium(Li),Beryllium(Be),Rubidium(Rb),Cesium(Cs),Zirconium(Zr),Hafnium(Hf),Niobium(Nb),Tantalum(Ta),Tungsten(W)and Tin(Sn)are important critical mineral resources.In China,rare metal mineral dep...Rare metals including Lithium(Li),Beryllium(Be),Rubidium(Rb),Cesium(Cs),Zirconium(Zr),Hafnium(Hf),Niobium(Nb),Tantalum(Ta),Tungsten(W)and Tin(Sn)are important critical mineral resources.In China,rare metal mineral deposits are spatially distributed mainly in the Altay and Southern Great Xingán Range regions in the Central Asian orogenic belt;in the Middle Qilian,South Qinling and East Qinling mountains regions in the Qilian-Qinling-Dabie orogenic belt;in the Western Sichuan and Bailongshan-Dahongliutan regions in the Kunlun-Songpan-Garze orogenic belt,and in the Northeastern Jiangxi,Northwestern Jiangxi,and Southern Hunan regions in South China.Major ore-forming epochs include Indosinian(mostly 200-240 Ma,in particular in western China)and the Yanshanian(mostly 120-160 Ma,in particular in South China).In addition,Bayan Obo,Inner Mongolia,northeastern China,with a complex formation history,hosts the largest REE and Nb deposits in China.There are six major rare metal mineral deposit types in China:Highly fractionated granite;Pegmatite;Alkaline granite;Carbonatite and alkaline rock;Volcanic;and Hydrothermal types.Two further types,namely the Leptynite type and Breccia pipe type,have recently been discovered in China,and are represented by the Yushishan Nb-Ta-(Zr-Hf-REE)and the Weilasituo Li-Rb-Sn-W-Zn-Pb deposits.Several most important controlling factors for rare metal mineral deposits are discussed,including geochemical behaviors and sources of the rare metals,highly evolved magmatic fractionation,and structural controls such as the metamorphic core complex setting,with a revised conceptual model for the latter.展开更多
The temporal-spatial pattern of linear cultural heritage in the context of the tourism industry is closely linked to heritage management.Using the 1800 km long Beijing-Hangzhou Grand Canal as an example,this study com...The temporal-spatial pattern of linear cultural heritage in the context of the tourism industry is closely linked to heritage management.Using the 1800 km long Beijing-Hangzhou Grand Canal as an example,this study compared the dynamic evolution of tourism businesses in Beijing,Liaocheng,and Yangzhou at three time points(2010,2015,and 2019)via nearest neighbor analysis,kernel density estimation,and the standard deviational ellipse.Next,a Geo-detector was used to examine the influencing factors.The results reveal significant growth regardless of the quantity or agglomeration degree from 2010 to 2019,and the direction of industrial expansion is consistent with the flow direction of the canal.Moreover,the explanatory powers of factors related to socioeconomic development and canal resources are obviously stronger than those of the natural environment.The findings of this study offer theoretical constructs and policy recommendations for the sustainable development of the Beijing-Hangzhou Grand Canal and other linear cultural heritage sites.展开更多
Gas quenching and vacuum quenching process are widely applied to accelerate solvent volatilization to induce nucleation of perovskites in blade-coating method.In this work,we found these two pre-crystallization proces...Gas quenching and vacuum quenching process are widely applied to accelerate solvent volatilization to induce nucleation of perovskites in blade-coating method.In this work,we found these two pre-crystallization processes lead to different order of crystallization dynamics within the perovskite thin film,resulting in the differences of additive distribution.We then tailor-designed an additive molecule named 1,3-bis(4-methoxyphenyl)thiourea to obtain films with fewer defects and holes at the buried interface,and prepared perovskite solar cells with a certified efficiency of 23.75%.Furthermore,this work also demonstrates an efficiency of 20.18%for the large-area perovskite solar module(PSM)with an aperture area of 60.84 cm^(2).The PSM possesses remarkable continuous operation stability for maximum power point tracking of T_(90)>1000 h in ambient air.展开更多
The vast majority of in vitro studies have demonstrated that PINK1 phosphorylates Parkin to work together in mitophagy to protect against neuronal degeneration.However,it remains largely unclear how PINK1 and Parkin a...The vast majority of in vitro studies have demonstrated that PINK1 phosphorylates Parkin to work together in mitophagy to protect against neuronal degeneration.However,it remains largely unclear how PINK1 and Parkin are expressed in mammalian brains.This has been difficult to address because of the intrinsically low levels of PINK1 and undetectable levels of phosphorylated Parkin in small animals.Understanding this issue is critical for elucidating the in vivo roles of PINK1 and Parkin.Recently,we showed that the PINK1 kinase is selectively expressed as a truncated form(PINK1–55)in the primate brain.In the present study,we used multiple antibodies,including our recently developed monoclonal anti-PINK1,to validate the selective expression of PINK1 in the primate brain.We found that PINK1 was stably expressed in the monkey brain at postnatal and adulthood stages,which is consistent with the findings that depleting PINK1 can cause neuronal loss in developing and adult monkey brains.PINK1 was enriched in the membrane-bound fractionations,whereas Parkin was soluble with a distinguishable distribution.Immunofluorescent double staining experiments showed that PINK1 and Parkin did not colocalize under physiological conditions in cultured monkey astrocytes,though they did colocalize on mitochondria when the cells were exposed to mitochondrial stress.These findings suggest that PINK1 and Parkin may have distinct roles beyond their well-known function in mitophagy during mitochondrial damage.展开更多
This paper introduces an optimized planning approach for integrating photovoltaic as distributed generation (PV-DG) into the radial distribution power systems, utilizing exhaustive load flow (ELF), loss sensitivity fa...This paper introduces an optimized planning approach for integrating photovoltaic as distributed generation (PV-DG) into the radial distribution power systems, utilizing exhaustive load flow (ELF), loss sensitivity factor (LSF), genetic algorithms (GA) methods, and numerical method based on LSF. The methodology aims to determine the optimal allocation and sizing of multiple PV-DG to minimize power loss through time series power flow analysis. An approach utilizing continuous sensitivity analysis is developed and inherently leverages power flow and loss equations to compute LSF of all buses in the system towards employing a dynamic PV-DG model for more accurate results. The algorithm uses a numerical grid search method to optimize PV-DG placement in a power distribution system, focusing on minimizing system losses. It combines iterative analysis, sensitivity assessment, and comprehensive visualization to identify and present the optimal PV-DG configurations. The present-ed algorithms are verified through co-simulation framework combining MATLAB and OpenDSS to carry out analysis for 12-bus radial distribution test system. The proposed numerical method is compared with other algorithms, such as ELF, LSF methods, and Genetic Algorithms (GA). Results show that the proposed numerical method performs well in comparison with LSF and ELF solutions.展开更多
BACKGROUND Red blood cell distribution width(RDW)is associated with the development and progression of various diseases.AIM To explore the association between pretreatment RDW and short-term outcomes after laparoscopi...BACKGROUND Red blood cell distribution width(RDW)is associated with the development and progression of various diseases.AIM To explore the association between pretreatment RDW and short-term outcomes after laparoscopic pancreatoduodenectomy(LPD).METHODS A total of 804 consecutive patients who underwent LPD at our hospital between March 2017 and November 2021 were retrospectively analyzed.Correlations between pretreatment RDW and clinicopathological characteristics and short-term outcomes were investigated.RESULTS Patients with higher pretreatment RDW were older,had higher Eastern Cooperative Oncology Group scores and were associated with poorer short-term outcomes than those with normal RDW.High pretreatment RDW was an independent risk factor for postoperative complications(POCs)(hazard ratio=2.973,95%confidence interval:2.032-4.350,P<0.001)and severe POCs of grade IIIa or higher(hazard ratio=3.138,95%confidence interval:2.042-4.824,P<0.001)based on the Clavien-Dino classification system.Subgroup analysis showed that high pretreatment RDW was an independent risk factor for Clavien-Dino classi-fication grade IIIb or higher POCs,a comprehensive complication index score≥26.2,severe postoperative pancreatic fistula,severe bile leakage and severe hemorrhage.High pretreatment RDW was positively associated with the neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio and was negatively associated with albumin and the prognostic nutritional index.CONCLUSION Pretreatment RDW was a special parameter for patients who underwent LPD.It was associated with malnutrition,severe inflammatory status and poorer short-term outcomes.RDW could be a surrogate marker for nutritional and inflammatory status in identifying patients who were at high risk of developing POCs after LPD.展开更多
The Beta Distribution is widely used in engineering and industrial applications. Goodness-of-fit procedures are revisited. Shapiro-Francia statistic is implemented in Beta distribution. A comparative study between the...The Beta Distribution is widely used in engineering and industrial applications. Goodness-of-fit procedures are revisited. Shapiro-Francia statistic is implemented in Beta distribution. A comparative study between the Anderson-Darling, Kolmogorov-Smirnov, Shapiro-Francia, and Chi-square goodness-of-fit test in testing for Beta distribution is performed using simulation.展开更多
The high proportion of uncertain distributed power sources and the access to large-scale random electric vehicle(EV)charging resources further aggravate the voltage fluctuation of the distribution network,and the exis...The high proportion of uncertain distributed power sources and the access to large-scale random electric vehicle(EV)charging resources further aggravate the voltage fluctuation of the distribution network,and the existing research has not deeply explored the EV active-reactive synergistic regulating characteristics,and failed to realize themulti-timescale synergistic control with other regulatingmeans,For this reason,this paper proposes amultilevel linkage coordinated optimization strategy to reduce the voltage deviation of the distribution network.Firstly,a capacitor bank reactive power compensation voltage control model and a distributed photovoltaic(PV)activereactive power regulationmodel are established.Additionally,an external characteristicmodel of EVactive-reactive power regulation is developed considering the four-quadrant operational characteristics of the EVcharger.Amultiobjective optimization model of the distribution network is then constructed considering the time-series coupling constraints of multiple types of voltage regulators.A multi-timescale control strategy is proposed by considering the impact of voltage regulators on active-reactive EV energy consumption and PV energy consumption.Then,a four-stage voltage control optimization strategy is proposed for various types of voltage regulators with multiple time scales.Themulti-objective optimization is solved with the improvedDrosophila algorithmto realize the power fluctuation control of the distribution network and themulti-stage voltage control optimization.Simulation results validate that the proposed voltage control optimization strategy achieves the coordinated control of decentralized voltage control resources in the distribution network.It effectively reduces the voltage deviation of the distribution network while ensuring the energy demand of EV users and enhancing the stability and economic efficiency of the distribution network.展开更多
The UK’s economic growth has witnessed instability over these years. While some sectors recorded positive performances, some recorded negative performances, and these unstable economic performances led to technical r...The UK’s economic growth has witnessed instability over these years. While some sectors recorded positive performances, some recorded negative performances, and these unstable economic performances led to technical recession for the third and fourth quarters of the year 2023. This study assessed the efficacy of the Generalised Additive Model for Location, Scale and Shape (GAMLSS) as a flexible distributional regression with smoothing additive terms in forecasting the UK economic growth in-sample and out-of-sample over the conventional Autoregressive Distributed Lag (ARDL) and Error Correction Model (ECM). The aim was to investigate the effectiveness and efficiency of GAMLSS models using a machine learning framework over the conventional time series econometric models by a rolling window. It is quantitative research which adopts a dataset obtained from the Office for National Statistics, covering 105 monthly observations of major economic indicators in the UK from January 2015 to September 2023. It consists of eleven variables, which include economic growth (Econ), consumer price index (CPI), inflation (Infl), manufacturing (Manuf), electricity and gas (ElGas), construction (Const), industries (Ind), wholesale and retail (WRet), real estate (REst), education (Edu) and health (Health). All computations and graphics in this study are obtained using R software version 4.4.1. The study revealed that GAMLSS models demonstrate superior outperformance in forecast accuracy over the ARDL and ECM models. Unlike other models used in the literature, the GAMLSS models were able to forecast both the future economic growth and the future distribution of the growth, thereby contributing to the empirical literature. The study identified manufacturing, electricity and gas, construction, industries, wholesale and retail, real estate, education, and health as key drivers of UK economic growth.展开更多
The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious materials.Consequently,the true triaxial compressio...The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious materials.Consequently,the true triaxial compression tests,CT scanning,SEM,and EDS tests were conducted on cemented gangue backfill samples(CGBSs)with various carbon nanotube concentrations(P_(CNT))that satisfied fractal theory for the PSD of aggregates.The mechanical properties,energy dissipations,and failure mechanisms of the CGBSs under true triaxial compression were systematically analyzed.The results indicate that appropriate carbon nanotubes(CNTs)effectively enhance the mechanical properties and energy dissipations of CGBSs through micropore filling and microcrack bridging,and the optimal effect appears at P_(CNT)of 0.08wt%.Taking PSD fractal dimension(D)of 2.500 as an example,compared to that of CGBS without CNT,the peak strength(σ_(p)),axial peak strain(ε_(1,p)),elastic strain energy(Ue),and dissipated energy(U_(d))increased by 12.76%,29.60%,19.05%,and90.39%,respectively.However,excessive CNTs can reduce the mechanical properties of CGBSs due to CNT agglomeration,manifesting a decrease inρ_(p),ε_(1,p),and the volumetric strain increment(Δε_(v))when P_(CNT)increases from 0.08wt%to 0.12wt%.Moreover,the addition of CNTs improved the integrity of CGBS after macroscopic failure,and crack extension in CGBSs appeared in two modes:detour and pass through the aggregates.Theσ_(p)and U_(d)firstly increase and then decrease with increasing D,and porosity shows the opposite trend.Theε_(1,p)andΔε_(v)are negatively correlated with D,and CGBS with D=2.150 has the maximum deformation parameters(ε_(1,p)=0.05079,Δε_(v)=0.01990)due to the frictional slip effect caused by coarse aggregates.With increasing D,the failure modes of CGBSs are sequentially manifested as oblique shear failure,"Y-shaped"shear failure,and conjugate shear failure.展开更多
The distribution networks sometimes suffer from excessive losses and voltage violations in densely populated areas. The aim of the present study is to improve the performance of a distribution network by successively ...The distribution networks sometimes suffer from excessive losses and voltage violations in densely populated areas. The aim of the present study is to improve the performance of a distribution network by successively applying mono-capacitor positioning, multiple positioning and reconfiguration processes using GA-based algorithms implemented in a Matlab environment. From the diagnostic study of this network, it was observed that a minimum voltage of 0.90 pu induces a voltage deviation of 5.26%, followed by active and reactive losses of 425.08 kW and 435.09 kVAR, respectively. Single placement with the NSGAII resulted in the placement of a 3000 kVAR capacitor at node 128, which proved to be the invariably neuralgic point. Multiple placements resulted in a 21.55% reduction in losses and a 0.74% regression in voltage profile performance. After topology optimization, the loss profile improved by 65.08% and the voltage profile improved by 1.05%. Genetic algorithms are efficient and effective tools for improving the performance of distribution networks, whose degradation is often dynamic due to the natural variability of loads.展开更多
Objective: This study aims to analyze the distribution of positive human papillomavirus (HPV) infections among women of appropriate age in Beiliu City during cervical cancer screening in 2024, providing data support f...Objective: This study aims to analyze the distribution of positive human papillomavirus (HPV) infections among women of appropriate age in Beiliu City during cervical cancer screening in 2024, providing data support for subsequent public health interventions. Methods: A retrospective analysis was conducted on the HPV test results from January 1, 2024, to November 30, 2024, at Beiliu Maternal and Child Health Hospital. We statistically analyzed the positive rates of different HPV genotypes and the co-infection status of multiple genotypes. Results: A total of 7558 individuals were tested, with 1103 positive cases identified, resulting in a positivity rate of 14.59%. Among these, HPV type 52 had the highest positive rate, accounting for 18.47%. The co-infection analysis showed that there were 788 cases with single genotype positivity, 236 with double genotype positivity, and 58 with triple genotype positivity, while cases with multiple genotypes simultaneously positive were relatively rare. Conclusion: The HPV infection rate among women of appropriate age in Beiliu City is relatively high, especially for high-risk HPV types. To reduce the future incidence of cervical cancer, it is recommended to enhance health education and vaccination efforts for this population.展开更多
基金Supported by the National Natural Science Foundation of China(No.41961144011)。
文摘Microplastics(MPs)pollution has emerged as a critical global environmental issue,for which rivers serve as key conduits for the transport of MPs from land to ocean.There remained a lack of clarity regarding the characteristics and transport patterns of MPs pollution in diverse environmental media and seasons within a river basin.The Jiulong River basin in Fujian,southeast China was studied as case,whose spatial-temporal distribution,pollution characteristics,and transport dynamics of MPs in both surface water and groundwater were analyzed.Additionally,the features of MPs in different land use types during the dry season were examined.Results show that in wet season,the abundance of MPs in river water varied from 840 to 12300 p/m^(3),with an average of 3920 p/m^(3);in groundwater,the range was 740-1820 p/m^(3),averaging 1107 p/m^(3);and from 68 to 951 p/kg,with an average value of 265 p/kg in the soil(dry weight).In dry season,levels of MPs in river water ranged from 580 to 8880 p/m^(3),with an average of 4034 p/m^(3);groundwater exhibited a range of 860-14980 p/m^(3),averaging 3453 p/m^(3).Fibers consistently dominated the morphology of MPs,of which polyethylene terephthalate was identified as the predominant composition in each environmental medium.Our findings underscore the spatial and temporal variability in distribution and contamination characteristics of MPs across different media.Notably,MPs abundance in river water and groundwater exhibited a seasonal pattern,being higher in levels in dry season than in wet season.The downstream transport of MPs was facilitated by surface runoff,in which MPs in groundwater and surface water could complement to each other.Furthermore,population density and human activities were identified as influential factors on the distribution and abundance of MPs.This study revealed the order of magnitude of difference in annual estimates of MPs entering the sea among different models.Additionally,the interception volume by mangrove forest in the Jiulong River estuary was estimated approximately 1.51×10^(10)MPs particles per year.Ecological interception shall be considered when estimating the fluxes of MPs into the sea.
基金Supported by projects of the National Natural Science Foundation of China(Nos.92062216,41888101).
文摘Highly evolved granite is an important sign of the mature continent crust and closely associated with deposits of rare metals.In this work,the authors undertake systematically zircon U-Pb ages and whole rock elemental data for highly evolved granitic intrusions from the Great Xing’an Range(GXR),NE China,to elucidate their discriminant criteria,spatial-temporal distribution,differentiation and geodynamic mecha-nism.Geochemical data of these highly evolved granites suggest that high w(SiO_(2))(>70%)and differentiation index(DI>88)could be quantified indicators,while strong Eu depletion,high TE_(1,3),lowΣREE and low Zr/Hf,Nb/Ta,K/Rb could only be qualitative indicators.Zircon U-Pb ages suggest that the highly evolved gran-ites in the GXR were mainly formed in Late Mesozoic,which can be divided into two major stages:Late Ju-rassic-early Early Cretaceous(162-136 Ma,peak at 138 Ma),and late Early Cretaceous(136-106 Ma,peak at 126 Ma).The highly evolved granites are mainly distributed in the central-southern GXR,and display a weakly trend of getting younger from northwest to southeast,meanwhile indicating the metallogenic potential of rare metals within the central GXR.The spatial-temporal distribution,combined with regional geological data,indicates the highly evolved Mesozoic granites in the GXR were emplaced in an extensional environ-ment,of which the Late Jurassic-early Early Cretaceous extension was related to the closure of the Mongol-Okhotsk Ocean and roll-back of the Paleo-Pacific Plate,while the late Early Cretaceous extension was mainly related to the roll-back of the Paleo-Pacific Plate.
文摘[Objective] This paper aimed to understand the area change and distribu- tion of medium-low yield farmland, and offered basis to the improvement of mediumlow farmland and its increase of grain production in Tianjin. [Method] Based on the statistical date of Tianjin and its relevant counties and districts, the yield standard was set up to classify high-yield, medium-yield and low-yield farmland in Tianjin. The author analyzed area change of medium-low yield farmland in six agricultural counties and districts （including Jixian County, Wuqing District, Baodi District, Ninghe County, Jinghai County and Dagang district of Binghai New Area） from 1980 to 2010. [Result] The results showed that the average yield of grain rose from 2 445 kg/hm^2 in 1980 to 5 130 kg/hm^2 in 2010, increasing 109.82%. The area of mediumlow yield farmland was reduced from 291 250.13 hm^2 in 1985 to 76 489.87 hm^2 in 2010, coming down 74%. In Tianjin, the area of medium-low yield farmland of 2010 accounted for 19% of the total farmland, of which the ratios of medium-low yield farmland of Jinghai County, Jixian County, Dagang district of Binghai New Area, Wuqing District, Baodi District and Ninghe County were 43.12%, 18.59%, 17.23%, 14.01%, 7.05% and 0, respectively. Low soil nutrient content, drought and water shortage, as well as soil salinization were the main yield limiting factors to mediumlow yield farmland in Tianjin in 2010. [Conclusion] The countermeasures to improve the medium-low yield farmland were proposed, involving enhancing the investment of the government, strengthening the construction of water conservancy infrastructure, further improving the soil fertility, as well as saline and alkaline land, optimizing the farming system and planting drought and salt tolerance crops, etc.
基金co-supported by National Natural Science Foundation of China (Project number 41502201)"Western Light" project of Chinese Academy of Sciences (XBBS201301)
文摘Dykes are a special kind of intrusive rocks which were formed by deep magma intruded into the existing brittle fractures in the crust.Dykes swarms in different tectonic environments are very significant to re-construct the
基金supported by the Special Scientific Research Fund of Public Welfare Profession of Ministry of Land and Resources of the People’s Republic of China (No. 201011057)
文摘1 Introduction Geochemical mapping at national and continental scales continues to present challenges worldwide due to variations in geologic and geotectonic units.Use of the proper sampling media can provide rich information on
基金funded by the Research on Prevention and Control Technology of Ecological Debris Flow Disasters from Department of Land and Resources of Sichuan Province (Grant No. KJ2018-24)the Natural Science Foundation of China (Grant No. 41772343)+2 种基金the Chinese Academy of Sciences and Organization Department of Sichuan Provincial Party Committee "Light of West China" Program (the key control techniques of glacial debris flow along the Sichuan-Tibet Railway)the Key International S&T Cooperation Projects (Grant No. 2016YFE0122400)the Natural Science Foundation of China (Grant No. 41471011)
文摘Grain composition plays a vital role in impact pressure of debris flow. Current approaches treat debris flow as uniform fluid and almost ignore its granular effects. A series of flume experiments have been carried out to explore the granular influence on the impact process of debris flow by using a contact surface pressure gauge sensor(Tactilus~?, produced by Sensor Products LLC). It is found that the maximum impact pressure for debris flow of low density fluctuates drastically with a long duration time while the fluctuation for flow of high density is short in time, respectively presenting logarithmic and linear form in longitudinal attenuation. This can be ascribed to the turbulence effect in the former and grain collisions and grainfluid interaction in the latter. The horizontal distribution of the impact pressure can be considered as the equivalent distribution. For engineering purposes, the longitudinal distribution of the pressure can be generalized to a triangular distribution, from which a new impact method considering granular effects is proposed.
基金National Natural Science Foundation of China(41375025)863 Program(2012AA120903,2011AA12A104-3)+2 种基金Public Welfare Research Foundation of China Meteorological Administration(GYHY201106044,GYHY201106045)Meteorological Application Demonstration Project(E310/1112)4th and 5th GOSAT/TANSO joint research Project 2013-2015
文摘The variation of the atmospheric Carbon Dioxide （CO2） concentration plays an important role in global cli- mate and agriculture. We analyzed the spatial-temporal characteristics of CO2 in the China region and around the globe with the CO2 column mixing ratios observed by the Japanese GOSAT satellite （Greenhouse Gases Observing Satellite）. In order to make sure that the accuracy of the CO2 data retrieved by the satellite meets the needs of the climate charac- teristics analyses, we ran a validation on the CO2 column mixing ratios retrieved by the satellite against the ground-based TCCON （Total Carbon Column Observing Network） observation data. The result shows that the two sets of data have a correlation coefficient of higher than 0.7, and a bias of within 2.2 ppmv. Therefore, the GOSAT CO2 da- ta can be used for the climate characteristics analysis of global CO2. Our analysis on the spatial-temporal characteristics of the CO2 column mixing ratios observed during the period of June 2009 through January 2014 proved that, with the impact of the natural emission of near ground CO2 and human activities, the global CO2 concentration has a significant latitudinal characteristics with its highest level averaging 390 oomv in the 0-40？N latitudinal zone in the Northern Hemisphere, and 387 ppmv in the Southern Hemisphere. China has a relatively higher CO2 concentration with the highest level exceeding 398 ppmv, and the eastern area higher than the western area. The variation of global CO2 concentration shows a seasonal pattern, i.e. the CO2 concen- tration reaches its highest in spring in the Northern Hemisphere averaging more than 392 ppmv, second highest in win- ter, and lowest in summer averaging less than 387 ppmv. It fluctuates the most in the Northern Hemisphere with an av- erage concentration of 392.5 ppmv in April, and 385.5 ppmv in July. While in the Southern Hemisphere, the seasonal fluctuation is smaller with the highest concentration occurring in July. Over the recent years, the global CO2 concentra- tion has shown an elevating trend with an average annual increase rate of 1.58 ppmv per year. It is a challenge that the human kind has to face to slow down the increase of the CO2 concentration.
基金Under the auspices of National Natural Science Foundation of China(No.41771537)Fundamental Research Funds for the Central Universities
文摘Earthquakes exhibit clear clustering on the earth. It is important to explore the spatial-temporal characteristics of seismicity clusters and their spatial heterogeneity. We analyze effects of plate space, tectonic style, and their interaction on characteristic of cluster.Based on data of earthquakes not less than moment magnitude(M_w) 5.6 from 1960 to 2014, this study used the spatial-temporal scan method to identify earthquake clusters. The results indicate that seismic spatial-temporal clusters can be classified into two types based on duration: persistent clusters and burst clusters. Finally, we analysed the spatial heterogeneity of the two types. The main conclusions are as follows: 1) Ninety percent of the persistent clusters last for 22-38 yr and show a high clustering likelihood;ninety percent of the burst clusters last for 1-1.78 yr and show a high relative risk. 2) The persistent clusters are mainly distributed in interplate zones, especially along the western margin of the Pacific Ocean. The burst clusters are distributed in both intraplate and interplate zones, slightly concentrated in the India-Eurasia interaction zone. 3) For the persistent type, plate interaction plays an important role in the distribution of the clusters’ likelihood and relative risk. In addition, the tectonic style further enhances the spatial heterogeneity. 4) For the burst type,neither plate activity nor tectonic style has an obvious effect on the distribution of the clusters’ likelihood and relative risk. Nevertheless,interaction between these two spatial factors enhances the spatial heterogeneity, especially in terms of relative risk.
基金financially supported by the National Key R&D Program of China(grant no.2017YFC0602405)the National Natural Science Foundation of China(grant no.42030811)。
文摘Rare metals including Lithium(Li),Beryllium(Be),Rubidium(Rb),Cesium(Cs),Zirconium(Zr),Hafnium(Hf),Niobium(Nb),Tantalum(Ta),Tungsten(W)and Tin(Sn)are important critical mineral resources.In China,rare metal mineral deposits are spatially distributed mainly in the Altay and Southern Great Xingán Range regions in the Central Asian orogenic belt;in the Middle Qilian,South Qinling and East Qinling mountains regions in the Qilian-Qinling-Dabie orogenic belt;in the Western Sichuan and Bailongshan-Dahongliutan regions in the Kunlun-Songpan-Garze orogenic belt,and in the Northeastern Jiangxi,Northwestern Jiangxi,and Southern Hunan regions in South China.Major ore-forming epochs include Indosinian(mostly 200-240 Ma,in particular in western China)and the Yanshanian(mostly 120-160 Ma,in particular in South China).In addition,Bayan Obo,Inner Mongolia,northeastern China,with a complex formation history,hosts the largest REE and Nb deposits in China.There are six major rare metal mineral deposit types in China:Highly fractionated granite;Pegmatite;Alkaline granite;Carbonatite and alkaline rock;Volcanic;and Hydrothermal types.Two further types,namely the Leptynite type and Breccia pipe type,have recently been discovered in China,and are represented by the Yushishan Nb-Ta-(Zr-Hf-REE)and the Weilasituo Li-Rb-Sn-W-Zn-Pb deposits.Several most important controlling factors for rare metal mineral deposits are discussed,including geochemical behaviors and sources of the rare metals,highly evolved magmatic fractionation,and structural controls such as the metamorphic core complex setting,with a revised conceptual model for the latter.
基金The National Natural Science Foundation of China(42301273)The R&D Program of Beijing Municipal Education Commission(SM202210015004)The Beijing Central Axis Protection Foundation(DYKT-2023-015).
文摘The temporal-spatial pattern of linear cultural heritage in the context of the tourism industry is closely linked to heritage management.Using the 1800 km long Beijing-Hangzhou Grand Canal as an example,this study compared the dynamic evolution of tourism businesses in Beijing,Liaocheng,and Yangzhou at three time points(2010,2015,and 2019)via nearest neighbor analysis,kernel density estimation,and the standard deviational ellipse.Next,a Geo-detector was used to examine the influencing factors.The results reveal significant growth regardless of the quantity or agglomeration degree from 2010 to 2019,and the direction of industrial expansion is consistent with the flow direction of the canal.Moreover,the explanatory powers of factors related to socioeconomic development and canal resources are obviously stronger than those of the natural environment.The findings of this study offer theoretical constructs and policy recommendations for the sustainable development of the Beijing-Hangzhou Grand Canal and other linear cultural heritage sites.
基金supported by National Natural Science Foundation of China(62104082)Guangdong Basic and Applied Basic Research Foundation(2022A1515010746,2022A1515011228,and 2022B1515120006)the Science and Technology Program of Guangzhou(202201010458).
文摘Gas quenching and vacuum quenching process are widely applied to accelerate solvent volatilization to induce nucleation of perovskites in blade-coating method.In this work,we found these two pre-crystallization processes lead to different order of crystallization dynamics within the perovskite thin film,resulting in the differences of additive distribution.We then tailor-designed an additive molecule named 1,3-bis(4-methoxyphenyl)thiourea to obtain films with fewer defects and holes at the buried interface,and prepared perovskite solar cells with a certified efficiency of 23.75%.Furthermore,this work also demonstrates an efficiency of 20.18%for the large-area perovskite solar module(PSM)with an aperture area of 60.84 cm^(2).The PSM possesses remarkable continuous operation stability for maximum power point tracking of T_(90)>1000 h in ambient air.
基金supported by the National Natural Science Foundation of China,Nos.32070534(to WY),32370567(to WY),82371874(to XL),81830032(to XL),82071421(to SL)Key Field Research and Development Program of Guangdong Province,No.2018B030337001(to XL)+2 种基金Guangzhou Key Research Program on Brain Science,No.202007030008(to XL)Department of Science and Technology of Guangdong Province,Nos.2021ZT09Y007,2020B121201006(to XL)Guangdong Basic and Applied Basic Research Foundation,Nos.2022A1515012301(to WY),2023B1515020031(to WY).
文摘The vast majority of in vitro studies have demonstrated that PINK1 phosphorylates Parkin to work together in mitophagy to protect against neuronal degeneration.However,it remains largely unclear how PINK1 and Parkin are expressed in mammalian brains.This has been difficult to address because of the intrinsically low levels of PINK1 and undetectable levels of phosphorylated Parkin in small animals.Understanding this issue is critical for elucidating the in vivo roles of PINK1 and Parkin.Recently,we showed that the PINK1 kinase is selectively expressed as a truncated form(PINK1–55)in the primate brain.In the present study,we used multiple antibodies,including our recently developed monoclonal anti-PINK1,to validate the selective expression of PINK1 in the primate brain.We found that PINK1 was stably expressed in the monkey brain at postnatal and adulthood stages,which is consistent with the findings that depleting PINK1 can cause neuronal loss in developing and adult monkey brains.PINK1 was enriched in the membrane-bound fractionations,whereas Parkin was soluble with a distinguishable distribution.Immunofluorescent double staining experiments showed that PINK1 and Parkin did not colocalize under physiological conditions in cultured monkey astrocytes,though they did colocalize on mitochondria when the cells were exposed to mitochondrial stress.These findings suggest that PINK1 and Parkin may have distinct roles beyond their well-known function in mitophagy during mitochondrial damage.
文摘This paper introduces an optimized planning approach for integrating photovoltaic as distributed generation (PV-DG) into the radial distribution power systems, utilizing exhaustive load flow (ELF), loss sensitivity factor (LSF), genetic algorithms (GA) methods, and numerical method based on LSF. The methodology aims to determine the optimal allocation and sizing of multiple PV-DG to minimize power loss through time series power flow analysis. An approach utilizing continuous sensitivity analysis is developed and inherently leverages power flow and loss equations to compute LSF of all buses in the system towards employing a dynamic PV-DG model for more accurate results. The algorithm uses a numerical grid search method to optimize PV-DG placement in a power distribution system, focusing on minimizing system losses. It combines iterative analysis, sensitivity assessment, and comprehensive visualization to identify and present the optimal PV-DG configurations. The present-ed algorithms are verified through co-simulation framework combining MATLAB and OpenDSS to carry out analysis for 12-bus radial distribution test system. The proposed numerical method is compared with other algorithms, such as ELF, LSF methods, and Genetic Algorithms (GA). Results show that the proposed numerical method performs well in comparison with LSF and ELF solutions.
基金Supported by the National Natural Science Foundation of China,No.81302124.
文摘BACKGROUND Red blood cell distribution width(RDW)is associated with the development and progression of various diseases.AIM To explore the association between pretreatment RDW and short-term outcomes after laparoscopic pancreatoduodenectomy(LPD).METHODS A total of 804 consecutive patients who underwent LPD at our hospital between March 2017 and November 2021 were retrospectively analyzed.Correlations between pretreatment RDW and clinicopathological characteristics and short-term outcomes were investigated.RESULTS Patients with higher pretreatment RDW were older,had higher Eastern Cooperative Oncology Group scores and were associated with poorer short-term outcomes than those with normal RDW.High pretreatment RDW was an independent risk factor for postoperative complications(POCs)(hazard ratio=2.973,95%confidence interval:2.032-4.350,P<0.001)and severe POCs of grade IIIa or higher(hazard ratio=3.138,95%confidence interval:2.042-4.824,P<0.001)based on the Clavien-Dino classification system.Subgroup analysis showed that high pretreatment RDW was an independent risk factor for Clavien-Dino classi-fication grade IIIb or higher POCs,a comprehensive complication index score≥26.2,severe postoperative pancreatic fistula,severe bile leakage and severe hemorrhage.High pretreatment RDW was positively associated with the neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio and was negatively associated with albumin and the prognostic nutritional index.CONCLUSION Pretreatment RDW was a special parameter for patients who underwent LPD.It was associated with malnutrition,severe inflammatory status and poorer short-term outcomes.RDW could be a surrogate marker for nutritional and inflammatory status in identifying patients who were at high risk of developing POCs after LPD.
文摘The Beta Distribution is widely used in engineering and industrial applications. Goodness-of-fit procedures are revisited. Shapiro-Francia statistic is implemented in Beta distribution. A comparative study between the Anderson-Darling, Kolmogorov-Smirnov, Shapiro-Francia, and Chi-square goodness-of-fit test in testing for Beta distribution is performed using simulation.
基金funded by the State Grid Corporation Science and Technology Project(5108-202218280A-2-391-XG).
文摘The high proportion of uncertain distributed power sources and the access to large-scale random electric vehicle(EV)charging resources further aggravate the voltage fluctuation of the distribution network,and the existing research has not deeply explored the EV active-reactive synergistic regulating characteristics,and failed to realize themulti-timescale synergistic control with other regulatingmeans,For this reason,this paper proposes amultilevel linkage coordinated optimization strategy to reduce the voltage deviation of the distribution network.Firstly,a capacitor bank reactive power compensation voltage control model and a distributed photovoltaic(PV)activereactive power regulationmodel are established.Additionally,an external characteristicmodel of EVactive-reactive power regulation is developed considering the four-quadrant operational characteristics of the EVcharger.Amultiobjective optimization model of the distribution network is then constructed considering the time-series coupling constraints of multiple types of voltage regulators.A multi-timescale control strategy is proposed by considering the impact of voltage regulators on active-reactive EV energy consumption and PV energy consumption.Then,a four-stage voltage control optimization strategy is proposed for various types of voltage regulators with multiple time scales.Themulti-objective optimization is solved with the improvedDrosophila algorithmto realize the power fluctuation control of the distribution network and themulti-stage voltage control optimization.Simulation results validate that the proposed voltage control optimization strategy achieves the coordinated control of decentralized voltage control resources in the distribution network.It effectively reduces the voltage deviation of the distribution network while ensuring the energy demand of EV users and enhancing the stability and economic efficiency of the distribution network.
文摘The UK’s economic growth has witnessed instability over these years. While some sectors recorded positive performances, some recorded negative performances, and these unstable economic performances led to technical recession for the third and fourth quarters of the year 2023. This study assessed the efficacy of the Generalised Additive Model for Location, Scale and Shape (GAMLSS) as a flexible distributional regression with smoothing additive terms in forecasting the UK economic growth in-sample and out-of-sample over the conventional Autoregressive Distributed Lag (ARDL) and Error Correction Model (ECM). The aim was to investigate the effectiveness and efficiency of GAMLSS models using a machine learning framework over the conventional time series econometric models by a rolling window. It is quantitative research which adopts a dataset obtained from the Office for National Statistics, covering 105 monthly observations of major economic indicators in the UK from January 2015 to September 2023. It consists of eleven variables, which include economic growth (Econ), consumer price index (CPI), inflation (Infl), manufacturing (Manuf), electricity and gas (ElGas), construction (Const), industries (Ind), wholesale and retail (WRet), real estate (REst), education (Edu) and health (Health). All computations and graphics in this study are obtained using R software version 4.4.1. The study revealed that GAMLSS models demonstrate superior outperformance in forecast accuracy over the ARDL and ECM models. Unlike other models used in the literature, the GAMLSS models were able to forecast both the future economic growth and the future distribution of the growth, thereby contributing to the empirical literature. The study identified manufacturing, electricity and gas, construction, industries, wholesale and retail, real estate, education, and health as key drivers of UK economic growth.
基金financially supported by the National Natural Science Foundation of China(Nos.52174092,51904290,and 52374147)the Natural Science Foundation of Jiangsu Province,China(No.BK20220157)+2 种基金the Fundamental Research Funds for the Central Universities,China(No.2022YCPY0202)the National Key Research and Development Program of China(No.2023YFC3804204)the Major Program of Xinjiang Uygur Autonomous Region S cience and Technology(No.2023A01002)。
文摘The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious materials.Consequently,the true triaxial compression tests,CT scanning,SEM,and EDS tests were conducted on cemented gangue backfill samples(CGBSs)with various carbon nanotube concentrations(P_(CNT))that satisfied fractal theory for the PSD of aggregates.The mechanical properties,energy dissipations,and failure mechanisms of the CGBSs under true triaxial compression were systematically analyzed.The results indicate that appropriate carbon nanotubes(CNTs)effectively enhance the mechanical properties and energy dissipations of CGBSs through micropore filling and microcrack bridging,and the optimal effect appears at P_(CNT)of 0.08wt%.Taking PSD fractal dimension(D)of 2.500 as an example,compared to that of CGBS without CNT,the peak strength(σ_(p)),axial peak strain(ε_(1,p)),elastic strain energy(Ue),and dissipated energy(U_(d))increased by 12.76%,29.60%,19.05%,and90.39%,respectively.However,excessive CNTs can reduce the mechanical properties of CGBSs due to CNT agglomeration,manifesting a decrease inρ_(p),ε_(1,p),and the volumetric strain increment(Δε_(v))when P_(CNT)increases from 0.08wt%to 0.12wt%.Moreover,the addition of CNTs improved the integrity of CGBS after macroscopic failure,and crack extension in CGBSs appeared in two modes:detour and pass through the aggregates.Theσ_(p)and U_(d)firstly increase and then decrease with increasing D,and porosity shows the opposite trend.Theε_(1,p)andΔε_(v)are negatively correlated with D,and CGBS with D=2.150 has the maximum deformation parameters(ε_(1,p)=0.05079,Δε_(v)=0.01990)due to the frictional slip effect caused by coarse aggregates.With increasing D,the failure modes of CGBSs are sequentially manifested as oblique shear failure,"Y-shaped"shear failure,and conjugate shear failure.
文摘The distribution networks sometimes suffer from excessive losses and voltage violations in densely populated areas. The aim of the present study is to improve the performance of a distribution network by successively applying mono-capacitor positioning, multiple positioning and reconfiguration processes using GA-based algorithms implemented in a Matlab environment. From the diagnostic study of this network, it was observed that a minimum voltage of 0.90 pu induces a voltage deviation of 5.26%, followed by active and reactive losses of 425.08 kW and 435.09 kVAR, respectively. Single placement with the NSGAII resulted in the placement of a 3000 kVAR capacitor at node 128, which proved to be the invariably neuralgic point. Multiple placements resulted in a 21.55% reduction in losses and a 0.74% regression in voltage profile performance. After topology optimization, the loss profile improved by 65.08% and the voltage profile improved by 1.05%. Genetic algorithms are efficient and effective tools for improving the performance of distribution networks, whose degradation is often dynamic due to the natural variability of loads.
文摘Objective: This study aims to analyze the distribution of positive human papillomavirus (HPV) infections among women of appropriate age in Beiliu City during cervical cancer screening in 2024, providing data support for subsequent public health interventions. Methods: A retrospective analysis was conducted on the HPV test results from January 1, 2024, to November 30, 2024, at Beiliu Maternal and Child Health Hospital. We statistically analyzed the positive rates of different HPV genotypes and the co-infection status of multiple genotypes. Results: A total of 7558 individuals were tested, with 1103 positive cases identified, resulting in a positivity rate of 14.59%. Among these, HPV type 52 had the highest positive rate, accounting for 18.47%. The co-infection analysis showed that there were 788 cases with single genotype positivity, 236 with double genotype positivity, and 58 with triple genotype positivity, while cases with multiple genotypes simultaneously positive were relatively rare. Conclusion: The HPV infection rate among women of appropriate age in Beiliu City is relatively high, especially for high-risk HPV types. To reduce the future incidence of cervical cancer, it is recommended to enhance health education and vaccination efforts for this population.
