Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and petroleum.To achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emp...Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and petroleum.To achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emphasis on structural durability and monitoring is required.This study focuses on the mechanical vibrations that occur in rotary drilling systems,which have a substantial impact on the structural integrity of drilling equipment.The study specifically investigates axial,torsional,and lateral vibrations,which might lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency stick-slip.These events not only hinder the efficiency of drilling but also lead to exhaustion and harm to the system’s components since they are difficult to be detected and controlled in real time.The study investigates the dynamic interactions of these vibrations,specifically in their high-frequency modes,usingfield data obtained from measurement while drilling.Thefindings have demonstrated the effect of strong coupling between the high-frequency modes of these vibrations on drilling sys-tem performance.The obtained results highlight the importance of considering the interconnected impacts of these vibrations when designing and implementing robust control systems.Therefore,integrating these compo-nents can increase the durability of drill bits and drill strings,as well as improve the ability to monitor and detect damage.Moreover,by exploiting thesefindings,the assessment of structural resilience in rotary drilling systems can be enhanced.Furthermore,the study demonstrates the capacity of structural health monitoring to improve the quality,dependability,and efficiency of rotary drilling systems in the petroleum industry.展开更多
The present study investigates the influence of embedment depth of isolated footing supporting moment-resisting frame buildings through scaled-down tests.These experiments utilize scaled models representing different ...The present study investigates the influence of embedment depth of isolated footing supporting moment-resisting frame buildings through scaled-down tests.These experiments utilize scaled models representing different building aspect ratios and footing embedment depths.All the model tests are subjected to scaled-down input ground motions of different intensities and magnitudes.These model tests are performed in laminar shear containers through shake table testing.The results obtained for different cases of soil-foundation-structure systems and fixed-base conditions are expressed in terms of natural frequency,peak spectral acceleration,frequency response,lateral deformation,inter-storey drifts,and rocking of the foundation.The analysis reveals that the natural frequency of the coupled system on isolated footings diminishes by 27.52%–58.21%relative to fixed-base conditions,highlighting the significance of accounting for soil-foundation-structure interaction effects.Moreover,a notable increase of 52.97%in the natural frequency of the coupled system is observed as the embedment depth of the footing increases from 0.75 to 6.Additionally,the study demonstrates that the inter-storey drift of the 5-storey building remains well within acceptable limits under dense soil conditions.Consequently,within the parameter range explored in this research,the study concludes that soil-foundation-structure interaction effects are insignificant for low-rise buildings(H≤15 m)supported on isolated footings during seismic events.展开更多
Due to technical limitations,existing vibration isolation and energy harvesting(VIEH)devices have poor performance at low frequency.This paper proposes a new multilink-spring mechanism(MLSM)that can be used to solve t...Due to technical limitations,existing vibration isolation and energy harvesting(VIEH)devices have poor performance at low frequency.This paper proposes a new multilink-spring mechanism(MLSM)that can be used to solve this problem.The VIEH performance of the MLSM under harmonic excitation and Gaussian white noise was analyzed.It was found that the MLSM has good vibration isolation performance for low-frequency isolation and the frequency band can be widened by adjusting parameters to achieve a higher energy harvesting power.By comparison with two special cases,the results show that the MLSM is basically the same as the other two oscillators in terms of vibration isolation but has better energy harvesting performance under multistable characteristics.The MLSM is expected to reduce the impact of vibration on high-precision sensitive equipment in some special sites such as subways and mines,and at the same time supply power to structural health monitoring devices.展开更多
The mass communication model and interactive ritual chain theory,which serve as communication paradigms in the new media era,facilitate and enhance the synergy between the fields of social history of medicine and heal...The mass communication model and interactive ritual chain theory,which serve as communication paradigms in the new media era,facilitate and enhance the synergy between the fields of social history of medicine and health communication.This study employs a comprehensive framework based on the five elements of the mass communication model:information source,communication subject,communication object,message content,and post-communication feedback.Additionally,it incorporates the interactive ritual chain theory to examine the evolving dynamics and developmental trajectory of research in the social history of medicine during the new media era.Conclusively,this paper acknowledges the existing interaction gaps in the interaction between health communication and the social history of medicine research while outlining the challenges for fostering collaboration and proposing strategic optimizations for effective integration.展开更多
In order to explore the effect mechanism of solvent on the synthesis of the metal organic framework materials, the microscopic interaction between solvent and framework and the effects of N,N-dimethyl-formamide(DMF) o...In order to explore the effect mechanism of solvent on the synthesis of the metal organic framework materials, the microscopic interaction between solvent and framework and the effects of N,N-dimethyl-formamide(DMF) or N-methyl- 2-pyrrolidone(NMP) on solvothermal synthesis of [Zn4O(BDC)3]8 were investigated through a combined DFT and experimental study. XRD and SEM showed that the absorbability of NMP in the pore of [Zn4O(BDC)3]8 was weaker than that of DMF. The thermal decomposition temperature of [Zn4O(BDC)3]8 synthesized in DMF was higher than that in NMP according to TG and FT-IR. In addition, the nitrogen sorption isotherms indicated that NMP improved gas sorption property of [Zn4O(BDC)3]8. The COSMO optimized calculations indicated that the total energy of Zn4O(BDC)3 in NMP was higher than that in DMF, and compared with non-solvent system, the charge of zinc atoms decreased and the charge value was the smallest in NMP. Furthermore, the interaction of DMF, NMP or DEF in [Zn4O(BDC)3]8 crystal model was calculated by DFT method. The results suggested that NMP should be easier to be removed from pore of materials than DMF from the point of view of energy state. It can be concluded that NMP was a favorable solvent to synthesize [Zn4O(BDC)3]8 and the microscopic mechanism was that the binding force between Zn4O(BDC)3 and NMP molecule was weaker than DMF.展开更多
The primary mechanism of secondary injury after cerebral ischemia may be the brain inflammation that emerges after an ischemic stroke,which promotes neuronal death and inhibits nerve tissue regeneration.As the first i...The primary mechanism of secondary injury after cerebral ischemia may be the brain inflammation that emerges after an ischemic stroke,which promotes neuronal death and inhibits nerve tissue regeneration.As the first immune cells to be activated after an ischemic stroke,microglia play an important immunomodulatory role in the progression of the condition.After an ischemic stroke,peripheral blood immune cells(mainly T cells)are recruited to the central nervous system by chemokines secreted by immune cells in the brain,where they interact with central nervous system cells(mainly microglia)to trigger a secondary neuroimmune response.This review summarizes the interactions between T cells and microglia in the immune-inflammatory processes of ischemic stroke.We found that,during ischemic stroke,T cells and microglia demonstrate a more pronounced synergistic effect.Th1,Th17,and M1 microglia can co-secrete proinflammatory factors,such as interferon-γ,tumor necrosis factor-α,and interleukin-1β,to promote neuroinflammation and exacerbate brain injury.Th2,Treg,and M2 microglia jointly secrete anti-inflammatory factors,such as interleukin-4,interleukin-10,and transforming growth factor-β,to inhibit the progression of neuroinflammation,as well as growth factors such as brain-derived neurotrophic factor to promote nerve regeneration and repair brain injury.Immune interactions between microglia and T cells influence the direction of the subsequent neuroinflammation,which in turn determines the prognosis of ischemic stroke patients.Clinical trials have been conducted on the ways to modulate the interactions between T cells and microglia toward anti-inflammatory communication using the immunosuppressant fingolimod or overdosing with Treg cells to promote neural tissue repair and reduce the damage caused by ischemic stroke.However,such studies have been relatively infrequent,and clinical experience is still insufficient.In summary,in ischemic stroke,T cell subsets and activated microglia act synergistically to regulate inflammatory progression,mainly by secreting inflammatory factors.In the future,a key research direction for ischemic stroke treatment could be rooted in the enhancement of anti-inflammatory factor secretion by promoting the generation of Th2 and Treg cells,along with the activation of M2-type microglia.These approaches may alleviate neuroinflammation and facilitate the repair of neural tissues.展开更多
With the rapid expansion of social media,analyzing emotions and their causes in texts has gained significant importance.Emotion-cause pair extraction enables the identification of causal relationships between emotions...With the rapid expansion of social media,analyzing emotions and their causes in texts has gained significant importance.Emotion-cause pair extraction enables the identification of causal relationships between emotions and their triggers within a text,facilitating a deeper understanding of expressed sentiments and their underlying reasons.This comprehension is crucial for making informed strategic decisions in various business and societal contexts.However,recent research approaches employing multi-task learning frameworks for modeling often face challenges such as the inability to simultaneouslymodel extracted features and their interactions,or inconsistencies in label prediction between emotion-cause pair extraction and independent assistant tasks like emotion and cause extraction.To address these issues,this study proposes an emotion-cause pair extraction methodology that incorporates joint feature encoding and task alignment mechanisms.The model consists of two primary components:First,joint feature encoding simultaneously generates features for emotion-cause pairs and clauses,enhancing feature interactions between emotion clauses,cause clauses,and emotion-cause pairs.Second,the task alignment technique is applied to reduce the labeling distance between emotion-cause pair extraction and the two assistant tasks,capturing deep semantic information interactions among tasks.The proposed method is evaluated on a Chinese benchmark corpus using 10-fold cross-validation,assessing key performance metrics such as precision,recall,and F1 score.Experimental results demonstrate that the model achieves an F1 score of 76.05%,surpassing the state-of-the-art by 1.03%.The proposed model exhibits significant improvements in emotion-cause pair extraction(ECPE)and cause extraction(CE)compared to existing methods,validating its effectiveness.This research introduces a novel approach based on joint feature encoding and task alignment mechanisms,contributing to advancements in emotion-cause pair extraction.However,the study’s limitation lies in the data sources,potentially restricting the generalizability of the findings.展开更多
Objective:To establish a progressive research strategy for“colonic components analysis-efficacy verification and mechanism exploration-gut microbiota”,screen pharmacodynamic substances,and investigate their mechanis...Objective:To establish a progressive research strategy for“colonic components analysis-efficacy verification and mechanism exploration-gut microbiota”,screen pharmacodynamic substances,and investigate their mechanism via gut microbiota.Methods:The pharmacodynamics of Gegen Qinlian decoction(GQD)were assessed using a mouse model of dextran sulfate sodium-induced ulcerative colitis(UC).Ultra-performance liquid chromatographyquadrupole-orbitrap mass spectrometer was used to identify the prototype and metabolic components of GQD in the colon during UC.To analyze the structure and function of characteristic genera of GQD and its active components,16S rRNA sequencing was performed.Results:We identified 67 prototypic and 14 metabolic components of GQD in the UC colon.The primary prototype components are flavonoids and alkaloids,including puerarin(PUE),baicalin(BAI),and berberine(BER).The metabolism was predominantly sulfonation.Efficacy verification showed that the main active components,puerarin,baicalin,and berberine,had good therapeutic effects on UC.The results of 16S rRNA gene sequencing showed that GQD improved UC by regulating the structure and function of the gut microbiota.The abundance of gut microbiota involved in the metabolism of the prototype componentswas influenced by the corresponding components.The function prediction results showed that PUE was the most comparable to GQD,with 24 consistent pathways.BAI and BER showed comparable gut microbiota regulation pathways.Characteristic pathways of BER include glucometabolic processes.Conclusion:This study focused on the key issues in the gut microbiota pathway and developed a progressive research strategy to understand the transformation mechanisms of colonic components.This research systematically analyzed the active components and metabolic transformation of GQD in the colon during the pathological state of UC,as well as changes in the structure and function of the gut microbiota,clarified the mechanism of GQD and its active components in improving UC via the gut microbiota pathway.展开更多
Accurately estimating protein–ligand binding free energy is crucial for drug design and biophysics, yet remains a challenging task. In this study, we applied the screening molecular mechanics/Poisson–Boltzmann surfa...Accurately estimating protein–ligand binding free energy is crucial for drug design and biophysics, yet remains a challenging task. In this study, we applied the screening molecular mechanics/Poisson–Boltzmann surface area(MM/PBSA)method in combination with various machine learning techniques to compute the binding free energies of protein–ligand interactions. Our results demonstrate that machine learning outperforms direct screening MM/PBSA calculations in predicting protein–ligand binding free energies. Notably, the random forest(RF) method exhibited the best predictive performance,with a Pearson correlation coefficient(rp) of 0.702 and a mean absolute error(MAE) of 1.379 kcal/mol. Furthermore, we analyzed feature importance rankings in the gradient boosting(GB), adaptive boosting(Ada Boost), and RF methods, and found that feature selection significantly impacted predictive performance. In particular, molecular weight(MW) and van der Waals(VDW) energies played a decisive role in the prediction. Overall, this study highlights the potential of combining machine learning methods with screening MM/PBSA for accurately predicting binding free energies in biosystems.展开更多
Bacillus mucilaginosus is a common soil bacterium,and usually used as a model bacterium in studying microbe-mineral interactions.Several reaction mechanisms of B.mucilaginosus weathering silicate minerals were propose...Bacillus mucilaginosus is a common soil bacterium,and usually used as a model bacterium in studying microbe-mineral interactions.Several reaction mechanisms of B.mucilaginosus weathering silicate minerals were proposed.However,the molecule mechanisms and detailed processes were still unclear.In this paper,bacterium-mineral interactions were studied in terms of variations in pH value over the experimental period,variations in mineral composition,weathering rates of silicate minerals and volatile metabolites in the culture medium,etc.,to further explore the bacterium-mineral interaction mechanisms.The results showed that B.mucilaginosus could enhance silicate mineral weathering obviously.The weathering rates were quite different for various kinds of silicate minerals,and the weathering rate of weathered adamellite could reach 150 mg/m2/d.Although B.mucilaginosus produced little acidic substance,pH in the microenvironment of bacterium-mineral complex might be far lower than that of the circumjacent environment;a large amount of acetic acid was found in the metabolites,and was likely to play an important role as a ligand.These results appear to suggest that acidolysis and ligand degradation are the main mechanisms of B.mucilaginosus dissolving silicate minerals,the formation of bacterium-mineral complexes is the necessary condition for the bacteria weathering silicate minerals,and extracelluar polysaccharides played important roles in bacterium-mineral interaction processes by forming bacterium-mineral complexes and maintaining the spe-cial physicochemical properties of microenvironment.展开更多
The mechanism of interaction relation between the rare-earth element Ce and elements Pb and Bi in Ag-based filler metal has been studied. The results show that the compounds CePb and CeBi with high melting point can b...The mechanism of interaction relation between the rare-earth element Ce and elements Pb and Bi in Ag-based filler metal has been studied. The results show that the compounds CePb and CeBi with high melting point can be easily produced between these three elements in the filler metal, which greatly limited the formation of the isolated phase Pb or Bi and also eliminated the bad effect of impurity elements Pb and Bi on the spreading property of Ag-based filler metal. The metallurgical and quantum-mechanical bond formation analysis show that a strong chemical affinity was existed between the rare-earth element Ce and impurity elements Pb and Bi, which was proved by the XRD analysis results.展开更多
Water–rock interaction(WRI)is a topic of interest in geology and geotechnical engineering.Many geological hazards and engineering safety problems are severe under the WRI.This study focuses on the water weakening of ...Water–rock interaction(WRI)is a topic of interest in geology and geotechnical engineering.Many geological hazards and engineering safety problems are severe under the WRI.This study focuses on the water weakening of rock strength and its infuencing factors(water content,immersion time,and wetting–drying cycles).The strength of the rock mass decreases to varying degrees with water content,immersion time,and wetting–drying cycles depending on the rock mass type and mineral composition.The corresponding acoustic emission count and intensity and infrared radiation intensity also weaken accordingly.WRI enhances the plasticity of rock mass and reduces its brittleness.Various microscopic methods for studying the pore characterization and weakening mechanism of the WRI were compared and analyzed.Various methods should be adopted to study the pore evolution of WRI comprehensively.Microscopic methods are used to study the weakening mechanism of WRI.In future work,the mechanical parameters of rocks weakened under long-term water immersion(over years)should be considered,and more attention should be paid to how the laboratory scale is applied to the engineering scale.展开更多
In this paper, the tropical air-sea interaction is discussed by using a simple air-sea coupled model, in which the inertia-gravity waves are filtered off and only the equatorial Rossby waves are reserved in both the a...In this paper, the tropical air-sea interaction is discussed by using a simple air-sea coupled model, in which the inertia-gravity waves are filtered off and only the equatorial Rossby waves are reserved in both the atmosphere and the ocean. There exist two kinds of air-sea interaction waves in the coupled model, that is, the high-frequency fast waves and the low-frequency slow waves. The phase speed of the fast waves is westward and the frequencies are close to those of the equatorial Rossby waves in the atmosphere. The slow waves propagate westward in the part of short wavelengths and eastward in that of long wavelengths. There exist instabilities for both the westward and eastward propagating slow waves. If the fast waves are filtered off, there is little effect on the slow waves which have great influence on the long range process in the tropical air-sea coupled system. According to the tropical air-sea interaction waves we obtain here, a possible explanation to the propagating process of ENSO events is given.展开更多
Objective Shale gas is as an important kind of unconventional natural gas,with a great resource potential,and its exploration and development has attracted much attention around the world.Organic matter（OM）pores are...Objective Shale gas is as an important kind of unconventional natural gas,with a great resource potential,and its exploration and development has attracted much attention around the world.Organic matter（OM）pores are a common constituent in shales and form the dominant pore network of many shale gas systems.展开更多
The interaction mechanism and phase evolution of ammonium polyphosphate（APP）mixed with muscovite（APP/muscovite）were studied by TG,XRD and SEM,respectively,during heating.When the temperature is not higher than 300...The interaction mechanism and phase evolution of ammonium polyphosphate（APP）mixed with muscovite（APP/muscovite）were studied by TG,XRD and SEM,respectively,during heating.When the temperature is not higher than 300 ℃,muscovite has no effect on the thermaldecomposition of APP,and the initialdecomposition temperature of APP/muscovite at 283 ℃ is basically the same as the APP at 295 ℃,and the main thermaldecomposition products are polyphosphoric acid and NH_4H_2PO_4 at 300 ℃.The polyphosphoric acid,the decomposition products of APP,can enable K and Siout of muscovite and interact with muscovite chemically to generate Al_2O_3·2SiO_2,α-SiO_2 and phosphates（AlPO_4 and K_5P_3O_（10））compounds during 400 ℃-800 ℃,which own obvious adhesive phenomenon and porous structure with the apparent porosity of 58.4%.Further reactions between phosphates other than reactions among Al_2O_3·2SiO_2 and α-SiO_2 can generate KAlP_2O_7 at 1 000 ℃ and the density of residualproduct is improved by low melting point phosphate filling pore to form relatively dense structure and decrease the apparent porosity to 44.4%.The flame resistant and self-supported ceramic materials are expected to enhance the fire-retarding synergistic effect between APP and muscovite.展开更多
Human immunodeficiency virus(HIV) and tuberculosis(TB) coinfection is a serious public health problem. HIV and TB promote each other, accelerating development of HIV to acquired immunodeficiency syndrome(AIDS) and hei...Human immunodeficiency virus(HIV) and tuberculosis(TB) coinfection is a serious public health problem. HIV and TB promote each other, accelerating development of HIV to acquired immunodeficiency syndrome(AIDS) and heightening TB mortality. Determining interaction mechanism between HIV and Mycobacterium tuberculosis can lead to development of effective treatments. This study summarizes prevalence status of AIDS and TB coinfection and research advances concerning their interaction mechanism.展开更多
Based on analysis of core observation, thin sections, cathodoluminescence, scanning electron microscope(SEM), etc., and geochemical testing of stable carbon and oxygen isotopes composition, element content, fluid incl...Based on analysis of core observation, thin sections, cathodoluminescence, scanning electron microscope(SEM), etc., and geochemical testing of stable carbon and oxygen isotopes composition, element content, fluid inclusions, and formation water, the fluid interaction mechanism and diagenetic reformation of fracture-pore basement reservoirs of epimetamorphic pyroclastic rock in the Beier Sag, Hailar Basin were studied. The results show that:(1) Two suites of reservoirs were developed in the basement, the weathering section and interior section, the interior section has a good reservoir zone reaching the standard of type I reservoir.(2) The secondary pores are formed by dissolution of carbonate minerals, feldspar, and tuff etc.(3) The diagenetic fluids include atmospheric freshwater, deep magmatic hydrothermal fluid, organic acids and hydrocarbon-bearing fluids.(4) The reservoir diagenetic reformation can be divided into four stages: initial consolidation, early supergene weathering-leaching, middle structural fracture-cementation-dissolution, and late organic acid-magmatic hydrothermal superimposed dissolution. Among them, the second and fourth stages are the stages for the formation of weathering crust and interior dissolution pore-cave reservoirs, respectively.展开更多
Carboxylmethyl cellulose(CMC) has become a commercial organic binder in agglomeration of iron ore concentrates. The relative molecular mass and degree of substitution(DS) of CMC have a large impact on its binding perf...Carboxylmethyl cellulose(CMC) has become a commercial organic binder in agglomeration of iron ore concentrates. The relative molecular mass and degree of substitution(DS) of CMC have a large impact on its binding performance. The interaction mechanism between CMC and iron ore particles was analyzed through Zeta potential measurements, adsorption measurements and infrared spectra. The results show that the interaction is chemical adsorption-oriented and the CMC's adsorption performance is related to the properties of CMC as well as the type of iron oxides. CMC has a greater affinity to Fe2O3 than Fe3O4, and CMC with higher relative molecular mass shows a higher adsorption isotherm. Pelletization of practical iron ore concentrates added with CMC further illustrates that CMC with higher relative molecular mass or DS exhibits a better binding performance, which is consistent with the results of adsorption tests.展开更多
Semi-metal friction material was applied widely in brake process of traffic and dynamical system. The friction materials with rare earth additive were manufactured by heating press molding process. The effects of diff...Semi-metal friction material was applied widely in brake process of traffic and dynamical system. The friction materials with rare earth additive were manufactured by heating press molding process. The effects of different reinforcing fibers and adhesives on the properties of the materials were studied by changing the formula. The results showed that the friction materials with YSM resin adhesive and hybrid fibers (Kevlar pulp and steel fiber) had higher and more stable friction coefficient and lower wear rate. Semi-metal friction materials with rare earths formed iron-rich surface layer in the worn surface, and the mechanisms of wear had obvious differences at typical temperature ranges.展开更多
A systematic analysis has been carried out to investigate the fields of application and interaction mechanism of polymeric carbohydrate, i.e. polysaccharides (including starch, dextrin, cellulose and cellulosic deriva...A systematic analysis has been carried out to investigate the fields of application and interaction mechanism of polymeric carbohydrate, i.e. polysaccharides (including starch, dextrin, cellulose and cellulosic derivatives) on various oxides and salt-type minerals in the article, interaction mechanisms of electrostatic, of hydrogen bonding, and of chemical interaction between polymeric carbohydrate and these minerals are put forward.展开更多
文摘Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and petroleum.To achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emphasis on structural durability and monitoring is required.This study focuses on the mechanical vibrations that occur in rotary drilling systems,which have a substantial impact on the structural integrity of drilling equipment.The study specifically investigates axial,torsional,and lateral vibrations,which might lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency stick-slip.These events not only hinder the efficiency of drilling but also lead to exhaustion and harm to the system’s components since they are difficult to be detected and controlled in real time.The study investigates the dynamic interactions of these vibrations,specifically in their high-frequency modes,usingfield data obtained from measurement while drilling.Thefindings have demonstrated the effect of strong coupling between the high-frequency modes of these vibrations on drilling sys-tem performance.The obtained results highlight the importance of considering the interconnected impacts of these vibrations when designing and implementing robust control systems.Therefore,integrating these compo-nents can increase the durability of drill bits and drill strings,as well as improve the ability to monitor and detect damage.Moreover,by exploiting thesefindings,the assessment of structural resilience in rotary drilling systems can be enhanced.Furthermore,the study demonstrates the capacity of structural health monitoring to improve the quality,dependability,and efficiency of rotary drilling systems in the petroleum industry.
基金fellowship received from the Department of Science and Technology(DST)under a unique scheme,“Innovation in Science Pursuit for Inspired Research(INSPIRE),”under the file number 20190000871,during the present work。
文摘The present study investigates the influence of embedment depth of isolated footing supporting moment-resisting frame buildings through scaled-down tests.These experiments utilize scaled models representing different building aspect ratios and footing embedment depths.All the model tests are subjected to scaled-down input ground motions of different intensities and magnitudes.These model tests are performed in laminar shear containers through shake table testing.The results obtained for different cases of soil-foundation-structure systems and fixed-base conditions are expressed in terms of natural frequency,peak spectral acceleration,frequency response,lateral deformation,inter-storey drifts,and rocking of the foundation.The analysis reveals that the natural frequency of the coupled system on isolated footings diminishes by 27.52%–58.21%relative to fixed-base conditions,highlighting the significance of accounting for soil-foundation-structure interaction effects.Moreover,a notable increase of 52.97%in the natural frequency of the coupled system is observed as the embedment depth of the footing increases from 0.75 to 6.Additionally,the study demonstrates that the inter-storey drift of the 5-storey building remains well within acceptable limits under dense soil conditions.Consequently,within the parameter range explored in this research,the study concludes that soil-foundation-structure interaction effects are insignificant for low-rise buildings(H≤15 m)supported on isolated footings during seismic events.
基金Project supported by Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2022A1515010967 and 2023A1515012821)the National Natural Science Foundation of China(Grant Nos.12002272 and 12272293)Opening Project of Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province(Grant No.SZDKF-202101)。
文摘Due to technical limitations,existing vibration isolation and energy harvesting(VIEH)devices have poor performance at low frequency.This paper proposes a new multilink-spring mechanism(MLSM)that can be used to solve this problem.The VIEH performance of the MLSM under harmonic excitation and Gaussian white noise was analyzed.It was found that the MLSM has good vibration isolation performance for low-frequency isolation and the frequency band can be widened by adjusting parameters to achieve a higher energy harvesting power.By comparison with two special cases,the results show that the MLSM is basically the same as the other two oscillators in terms of vibration isolation but has better energy harvesting performance under multistable characteristics.The MLSM is expected to reduce the impact of vibration on high-precision sensitive equipment in some special sites such as subways and mines,and at the same time supply power to structural health monitoring devices.
基金University of Science and Technology of China Quality Project History of Medicine(2023YCZX02)Digital Museum Construction Project of Chinese Centre for Disease Control and Prevention(BB2110240080)The National Key R&D project granted by the Ministry of Science and Technology(2018YFA0902400).
文摘The mass communication model and interactive ritual chain theory,which serve as communication paradigms in the new media era,facilitate and enhance the synergy between the fields of social history of medicine and health communication.This study employs a comprehensive framework based on the five elements of the mass communication model:information source,communication subject,communication object,message content,and post-communication feedback.Additionally,it incorporates the interactive ritual chain theory to examine the evolving dynamics and developmental trajectory of research in the social history of medicine during the new media era.Conclusively,this paper acknowledges the existing interaction gaps in the interaction between health communication and the social history of medicine research while outlining the challenges for fostering collaboration and proposing strategic optimizations for effective integration.
基金Project(51104185)supported by the National Natural Science Foundation of ChinaProject(2010QZZD003)supported by the Key Project of Central South University of Fundamental Research Funds for the Central Universities of China
文摘In order to explore the effect mechanism of solvent on the synthesis of the metal organic framework materials, the microscopic interaction between solvent and framework and the effects of N,N-dimethyl-formamide(DMF) or N-methyl- 2-pyrrolidone(NMP) on solvothermal synthesis of [Zn4O(BDC)3]8 were investigated through a combined DFT and experimental study. XRD and SEM showed that the absorbability of NMP in the pore of [Zn4O(BDC)3]8 was weaker than that of DMF. The thermal decomposition temperature of [Zn4O(BDC)3]8 synthesized in DMF was higher than that in NMP according to TG and FT-IR. In addition, the nitrogen sorption isotherms indicated that NMP improved gas sorption property of [Zn4O(BDC)3]8. The COSMO optimized calculations indicated that the total energy of Zn4O(BDC)3 in NMP was higher than that in DMF, and compared with non-solvent system, the charge of zinc atoms decreased and the charge value was the smallest in NMP. Furthermore, the interaction of DMF, NMP or DEF in [Zn4O(BDC)3]8 crystal model was calculated by DFT method. The results suggested that NMP should be easier to be removed from pore of materials than DMF from the point of view of energy state. It can be concluded that NMP was a favorable solvent to synthesize [Zn4O(BDC)3]8 and the microscopic mechanism was that the binding force between Zn4O(BDC)3 and NMP molecule was weaker than DMF.
基金supported by the National Natural Science Foundation of China,Nos.82104560(to CL),U21A20400(to QW)the Natural Science Foundation of Beijing,No.7232279(to XW)the Project of Beijing University of Chinese Medicine,No.2022-JYB-JBZR-004(to XW)。
文摘The primary mechanism of secondary injury after cerebral ischemia may be the brain inflammation that emerges after an ischemic stroke,which promotes neuronal death and inhibits nerve tissue regeneration.As the first immune cells to be activated after an ischemic stroke,microglia play an important immunomodulatory role in the progression of the condition.After an ischemic stroke,peripheral blood immune cells(mainly T cells)are recruited to the central nervous system by chemokines secreted by immune cells in the brain,where they interact with central nervous system cells(mainly microglia)to trigger a secondary neuroimmune response.This review summarizes the interactions between T cells and microglia in the immune-inflammatory processes of ischemic stroke.We found that,during ischemic stroke,T cells and microglia demonstrate a more pronounced synergistic effect.Th1,Th17,and M1 microglia can co-secrete proinflammatory factors,such as interferon-γ,tumor necrosis factor-α,and interleukin-1β,to promote neuroinflammation and exacerbate brain injury.Th2,Treg,and M2 microglia jointly secrete anti-inflammatory factors,such as interleukin-4,interleukin-10,and transforming growth factor-β,to inhibit the progression of neuroinflammation,as well as growth factors such as brain-derived neurotrophic factor to promote nerve regeneration and repair brain injury.Immune interactions between microglia and T cells influence the direction of the subsequent neuroinflammation,which in turn determines the prognosis of ischemic stroke patients.Clinical trials have been conducted on the ways to modulate the interactions between T cells and microglia toward anti-inflammatory communication using the immunosuppressant fingolimod or overdosing with Treg cells to promote neural tissue repair and reduce the damage caused by ischemic stroke.However,such studies have been relatively infrequent,and clinical experience is still insufficient.In summary,in ischemic stroke,T cell subsets and activated microglia act synergistically to regulate inflammatory progression,mainly by secreting inflammatory factors.In the future,a key research direction for ischemic stroke treatment could be rooted in the enhancement of anti-inflammatory factor secretion by promoting the generation of Th2 and Treg cells,along with the activation of M2-type microglia.These approaches may alleviate neuroinflammation and facilitate the repair of neural tissues.
文摘With the rapid expansion of social media,analyzing emotions and their causes in texts has gained significant importance.Emotion-cause pair extraction enables the identification of causal relationships between emotions and their triggers within a text,facilitating a deeper understanding of expressed sentiments and their underlying reasons.This comprehension is crucial for making informed strategic decisions in various business and societal contexts.However,recent research approaches employing multi-task learning frameworks for modeling often face challenges such as the inability to simultaneouslymodel extracted features and their interactions,or inconsistencies in label prediction between emotion-cause pair extraction and independent assistant tasks like emotion and cause extraction.To address these issues,this study proposes an emotion-cause pair extraction methodology that incorporates joint feature encoding and task alignment mechanisms.The model consists of two primary components:First,joint feature encoding simultaneously generates features for emotion-cause pairs and clauses,enhancing feature interactions between emotion clauses,cause clauses,and emotion-cause pairs.Second,the task alignment technique is applied to reduce the labeling distance between emotion-cause pair extraction and the two assistant tasks,capturing deep semantic information interactions among tasks.The proposed method is evaluated on a Chinese benchmark corpus using 10-fold cross-validation,assessing key performance metrics such as precision,recall,and F1 score.Experimental results demonstrate that the model achieves an F1 score of 76.05%,surpassing the state-of-the-art by 1.03%.The proposed model exhibits significant improvements in emotion-cause pair extraction(ECPE)and cause extraction(CE)compared to existing methods,validating its effectiveness.This research introduces a novel approach based on joint feature encoding and task alignment mechanisms,contributing to advancements in emotion-cause pair extraction.However,the study’s limitation lies in the data sources,potentially restricting the generalizability of the findings.
基金supported by Fundamental Research Funds for the Central Universities(2022-ZXFZJJ-028).
文摘Objective:To establish a progressive research strategy for“colonic components analysis-efficacy verification and mechanism exploration-gut microbiota”,screen pharmacodynamic substances,and investigate their mechanism via gut microbiota.Methods:The pharmacodynamics of Gegen Qinlian decoction(GQD)were assessed using a mouse model of dextran sulfate sodium-induced ulcerative colitis(UC).Ultra-performance liquid chromatographyquadrupole-orbitrap mass spectrometer was used to identify the prototype and metabolic components of GQD in the colon during UC.To analyze the structure and function of characteristic genera of GQD and its active components,16S rRNA sequencing was performed.Results:We identified 67 prototypic and 14 metabolic components of GQD in the UC colon.The primary prototype components are flavonoids and alkaloids,including puerarin(PUE),baicalin(BAI),and berberine(BER).The metabolism was predominantly sulfonation.Efficacy verification showed that the main active components,puerarin,baicalin,and berberine,had good therapeutic effects on UC.The results of 16S rRNA gene sequencing showed that GQD improved UC by regulating the structure and function of the gut microbiota.The abundance of gut microbiota involved in the metabolism of the prototype componentswas influenced by the corresponding components.The function prediction results showed that PUE was the most comparable to GQD,with 24 consistent pathways.BAI and BER showed comparable gut microbiota regulation pathways.Characteristic pathways of BER include glucometabolic processes.Conclusion:This study focused on the key issues in the gut microbiota pathway and developed a progressive research strategy to understand the transformation mechanisms of colonic components.This research systematically analyzed the active components and metabolic transformation of GQD in the colon during the pathological state of UC,as well as changes in the structure and function of the gut microbiota,clarified the mechanism of GQD and its active components in improving UC via the gut microbiota pathway.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12222506, 12347102, 12447164, and 12174184)。
文摘Accurately estimating protein–ligand binding free energy is crucial for drug design and biophysics, yet remains a challenging task. In this study, we applied the screening molecular mechanics/Poisson–Boltzmann surface area(MM/PBSA)method in combination with various machine learning techniques to compute the binding free energies of protein–ligand interactions. Our results demonstrate that machine learning outperforms direct screening MM/PBSA calculations in predicting protein–ligand binding free energies. Notably, the random forest(RF) method exhibited the best predictive performance,with a Pearson correlation coefficient(rp) of 0.702 and a mean absolute error(MAE) of 1.379 kcal/mol. Furthermore, we analyzed feature importance rankings in the gradient boosting(GB), adaptive boosting(Ada Boost), and RF methods, and found that feature selection significantly impacted predictive performance. In particular, molecular weight(MW) and van der Waals(VDW) energies played a decisive role in the prediction. Overall, this study highlights the potential of combining machine learning methods with screening MM/PBSA for accurately predicting binding free energies in biosystems.
基金supported by the National High Technology Research and Development Program of China (2008AA06Z108)
文摘Bacillus mucilaginosus is a common soil bacterium,and usually used as a model bacterium in studying microbe-mineral interactions.Several reaction mechanisms of B.mucilaginosus weathering silicate minerals were proposed.However,the molecule mechanisms and detailed processes were still unclear.In this paper,bacterium-mineral interactions were studied in terms of variations in pH value over the experimental period,variations in mineral composition,weathering rates of silicate minerals and volatile metabolites in the culture medium,etc.,to further explore the bacterium-mineral interaction mechanisms.The results showed that B.mucilaginosus could enhance silicate mineral weathering obviously.The weathering rates were quite different for various kinds of silicate minerals,and the weathering rate of weathered adamellite could reach 150 mg/m2/d.Although B.mucilaginosus produced little acidic substance,pH in the microenvironment of bacterium-mineral complex might be far lower than that of the circumjacent environment;a large amount of acetic acid was found in the metabolites,and was likely to play an important role as a ligand.These results appear to suggest that acidolysis and ligand degradation are the main mechanisms of B.mucilaginosus dissolving silicate minerals,the formation of bacterium-mineral complexes is the necessary condition for the bacteria weathering silicate minerals,and extracelluar polysaccharides played important roles in bacterium-mineral interaction processes by forming bacterium-mineral complexes and maintaining the spe-cial physicochemical properties of microenvironment.
文摘The mechanism of interaction relation between the rare-earth element Ce and elements Pb and Bi in Ag-based filler metal has been studied. The results show that the compounds CePb and CeBi with high melting point can be easily produced between these three elements in the filler metal, which greatly limited the formation of the isolated phase Pb or Bi and also eliminated the bad effect of impurity elements Pb and Bi on the spreading property of Ag-based filler metal. The metallurgical and quantum-mechanical bond formation analysis show that a strong chemical affinity was existed between the rare-earth element Ce and impurity elements Pb and Bi, which was proved by the XRD analysis results.
基金the National Natural Science Foundation of China(52104155)Natural Science Foundation of Beijing(8212032)Fundamental Research Funds for the Central Universities(2023YQNY).
文摘Water–rock interaction(WRI)is a topic of interest in geology and geotechnical engineering.Many geological hazards and engineering safety problems are severe under the WRI.This study focuses on the water weakening of rock strength and its infuencing factors(water content,immersion time,and wetting–drying cycles).The strength of the rock mass decreases to varying degrees with water content,immersion time,and wetting–drying cycles depending on the rock mass type and mineral composition.The corresponding acoustic emission count and intensity and infrared radiation intensity also weaken accordingly.WRI enhances the plasticity of rock mass and reduces its brittleness.Various microscopic methods for studying the pore characterization and weakening mechanism of the WRI were compared and analyzed.Various methods should be adopted to study the pore evolution of WRI comprehensively.Microscopic methods are used to study the weakening mechanism of WRI.In future work,the mechanical parameters of rocks weakened under long-term water immersion(over years)should be considered,and more attention should be paid to how the laboratory scale is applied to the engineering scale.
文摘In this paper, the tropical air-sea interaction is discussed by using a simple air-sea coupled model, in which the inertia-gravity waves are filtered off and only the equatorial Rossby waves are reserved in both the atmosphere and the ocean. There exist two kinds of air-sea interaction waves in the coupled model, that is, the high-frequency fast waves and the low-frequency slow waves. The phase speed of the fast waves is westward and the frequencies are close to those of the equatorial Rossby waves in the atmosphere. The slow waves propagate westward in the part of short wavelengths and eastward in that of long wavelengths. There exist instabilities for both the westward and eastward propagating slow waves. If the fast waves are filtered off, there is little effect on the slow waves which have great influence on the long range process in the tropical air-sea coupled system. According to the tropical air-sea interaction waves we obtain here, a possible explanation to the propagating process of ENSO events is given.
基金supported by the National Natural Science Foundation of China(grant No.41202103)China Postdoctoral Science Foundation(grant No. 2016M591350)
文摘Objective Shale gas is as an important kind of unconventional natural gas,with a great resource potential,and its exploration and development has attracted much attention around the world.Organic matter（OM）pores are a common constituent in shales and form the dominant pore network of many shale gas systems.
基金Funded by the National Natural Science Foundation of China(No.51472188)
文摘The interaction mechanism and phase evolution of ammonium polyphosphate（APP）mixed with muscovite（APP/muscovite）were studied by TG,XRD and SEM,respectively,during heating.When the temperature is not higher than 300 ℃,muscovite has no effect on the thermaldecomposition of APP,and the initialdecomposition temperature of APP/muscovite at 283 ℃ is basically the same as the APP at 295 ℃,and the main thermaldecomposition products are polyphosphoric acid and NH_4H_2PO_4 at 300 ℃.The polyphosphoric acid,the decomposition products of APP,can enable K and Siout of muscovite and interact with muscovite chemically to generate Al_2O_3·2SiO_2,α-SiO_2 and phosphates（AlPO_4 and K_5P_3O_（10））compounds during 400 ℃-800 ℃,which own obvious adhesive phenomenon and porous structure with the apparent porosity of 58.4%.Further reactions between phosphates other than reactions among Al_2O_3·2SiO_2 and α-SiO_2 can generate KAlP_2O_7 at 1 000 ℃ and the density of residualproduct is improved by low melting point phosphate filling pore to form relatively dense structure and decrease the apparent porosity to 44.4%.The flame resistant and self-supported ceramic materials are expected to enhance the fire-retarding synergistic effect between APP and muscovite.
文摘Human immunodeficiency virus(HIV) and tuberculosis(TB) coinfection is a serious public health problem. HIV and TB promote each other, accelerating development of HIV to acquired immunodeficiency syndrome(AIDS) and heightening TB mortality. Determining interaction mechanism between HIV and Mycobacterium tuberculosis can lead to development of effective treatments. This study summarizes prevalence status of AIDS and TB coinfection and research advances concerning their interaction mechanism.
基金Supported by the PetroChina Science and Technology Project(2017-5307034-000002).
文摘Based on analysis of core observation, thin sections, cathodoluminescence, scanning electron microscope(SEM), etc., and geochemical testing of stable carbon and oxygen isotopes composition, element content, fluid inclusions, and formation water, the fluid interaction mechanism and diagenetic reformation of fracture-pore basement reservoirs of epimetamorphic pyroclastic rock in the Beier Sag, Hailar Basin were studied. The results show that:(1) Two suites of reservoirs were developed in the basement, the weathering section and interior section, the interior section has a good reservoir zone reaching the standard of type I reservoir.(2) The secondary pores are formed by dissolution of carbonate minerals, feldspar, and tuff etc.(3) The diagenetic fluids include atmospheric freshwater, deep magmatic hydrothermal fluid, organic acids and hydrocarbon-bearing fluids.(4) The reservoir diagenetic reformation can be divided into four stages: initial consolidation, early supergene weathering-leaching, middle structural fracture-cementation-dissolution, and late organic acid-magmatic hydrothermal superimposed dissolution. Among them, the second and fourth stages are the stages for the formation of weathering crust and interior dissolution pore-cave reservoirs, respectively.
基金Project(2012zzts101)supported by the Fundamental Research Funds for the Central Universities,China
文摘Carboxylmethyl cellulose(CMC) has become a commercial organic binder in agglomeration of iron ore concentrates. The relative molecular mass and degree of substitution(DS) of CMC have a large impact on its binding performance. The interaction mechanism between CMC and iron ore particles was analyzed through Zeta potential measurements, adsorption measurements and infrared spectra. The results show that the interaction is chemical adsorption-oriented and the CMC's adsorption performance is related to the properties of CMC as well as the type of iron oxides. CMC has a greater affinity to Fe2O3 than Fe3O4, and CMC with higher relative molecular mass shows a higher adsorption isotherm. Pelletization of practical iron ore concentrates added with CMC further illustrates that CMC with higher relative molecular mass or DS exhibits a better binding performance, which is consistent with the results of adsorption tests.
文摘Semi-metal friction material was applied widely in brake process of traffic and dynamical system. The friction materials with rare earth additive were manufactured by heating press molding process. The effects of different reinforcing fibers and adhesives on the properties of the materials were studied by changing the formula. The results showed that the friction materials with YSM resin adhesive and hybrid fibers (Kevlar pulp and steel fiber) had higher and more stable friction coefficient and lower wear rate. Semi-metal friction materials with rare earths formed iron-rich surface layer in the worn surface, and the mechanisms of wear had obvious differences at typical temperature ranges.
文摘A systematic analysis has been carried out to investigate the fields of application and interaction mechanism of polymeric carbohydrate, i.e. polysaccharides (including starch, dextrin, cellulose and cellulosic derivatives) on various oxides and salt-type minerals in the article, interaction mechanisms of electrostatic, of hydrogen bonding, and of chemical interaction between polymeric carbohydrate and these minerals are put forward.
