The second generation single crystal superalloy DD6 with 0.10%Hf and 0.34%Hf （in mass fraction） was subjected to high-cycle fatigue （HCF） loading at temperatures of 700 ℃ in ambient atmosphere. SEM was used to de...The second generation single crystal superalloy DD6 with 0.10%Hf and 0.34%Hf （in mass fraction） was subjected to high-cycle fatigue （HCF） loading at temperatures of 700 ℃ in ambient atmosphere. SEM was used to determine the initiation site and the failure mechanism. Evolution of the microstructure was investigated by TEM observation. The results show that fatigue limit of DD6 alloy with 0.34%Hf is a little smaller than that of the alloy with 0.10%Hf. The fatigue cracks initiated on the surface or near the surface of the specimens. The crack would propagate along { 111 } octahedral slip planes, rather than perpendicular to the loading axis of specimen. Typical fatigue striation formed in steady propagation of fatigue crack. The fracture mechanisms of the high cycle fatigue of DD6 alloys with 0.10%Hf and 0.34%Hf are quasi-cleavage fracture. Different types of dislocation structures were developed during high cycle fatigue deformation.展开更多
Voluminous granitoids are widely distributed in the Langshan region,northeast of the Alxa block,and record the evolutionary processes of the southern Central Asian Orogenic Belt.The Dabashan pluton was emplaced into t...Voluminous granitoids are widely distributed in the Langshan region,northeast of the Alxa block,and record the evolutionary processes of the southern Central Asian Orogenic Belt.The Dabashan pluton was emplaced into the Paleoproterozoic Diebusige complex.Early Carboniferous zircon LA-ICP MS U-Pb ages were from 327 Ma to 346 Ma.The Dabashan pluton can be classified as monzogranite and syenogranite,and exhibits high K2 O contents and K2 O/Na2 O ratios,which reveal a high-K calc-alkaline nature.The samples display strongly fractionated REE patterns,and are enriched in large ion lithophile elements(LILE)relative to high field strength elements(HFSE).The Dabashan plutons display unusually high Ba(823–2817 ppm)and Sr(166–520 ppm)contents and K/Rb ratios(315–627),but low Rb/Ba ratios(0.02–0.14),and exhibit fertile zircon Hf isotopic compositions[εHf(t)=-14 to-20],which are comparable to those of typical high Ba–Sr granitoids.Based on the geochemical compositions of the samples,we suggest that subducted sediments and ancient crustal materials both played important roles in their generation.Basaltic melts were derived from partial melting of subcontinental lithophile mantle metasomatized by subducted sediment-related melts with residual garnet in the source,which caused partial melting of ancient lower crust.Magmas derived from underplating ascended and emplaced in the middle–upper crust at different depths.The resultant magmas experienced some degree of fractional crystallization during their ascent.Given these geochemical characteristics,together with regional tectonic,magmatic,and structure analysis data,an active continental margin environment is proposed for the generation of these rocks.展开更多
In this letter,a kind of associated synchronization algorithm which is suitable for HF(High Frequency) broadband OFDM(Orthogonal Frequency Division Multiplexing) system is presented based on describing and constructin...In this letter,a kind of associated synchronization algorithm which is suitable for HF(High Frequency) broadband OFDM(Orthogonal Frequency Division Multiplexing) system is presented based on describing and constructing the GMW(Gorden,Mills and Welch) sequence. The algorithm is based on the Schmidl and Minn's symbol timing principle,the constructed GMW sequence is trans-mitted and disposed,and the synchronization is adjudicated using the correlation of GMW sequence. The simulation result indicates that this algorithm has high performance synchronization ability under the low SNR(Signal to Noise Ratio) at two different kinds of channel models.展开更多
Inter-turn fault is a serious stator winding short-circuit fault of permanent magnet synchronous machine(PMSM). Once it occurs, it produces a huge short-circuit current that poses a great risk to the safe operation of...Inter-turn fault is a serious stator winding short-circuit fault of permanent magnet synchronous machine(PMSM). Once it occurs, it produces a huge short-circuit current that poses a great risk to the safe operation of PMSM. Thus, an inter-turn short-circuit fault(ITSCF) diagnosis method based on high frequency(HF) voltage residual is proposed in this paper with proper HF signal injection. First, the analytical models of PMSM after the ITSCF are deduced. Based on the model, the voltage residual at low frequency(LF) and HF can be obtained. It is revealed that the HF voltage residual has a stronger ITSCF detection capability compared to the LF voltage residual. To obtain optimal fault signature, a 3-phase symmetrical HF voltage is injected into the machine drive system, and the HF voltage residuals are extracted. The fault indicator is defined as the standard deviation of the 3-phase HF voltage residuals. The effectiveness of the proposed ITSCF diagnosis method is verified by experiments on a triple 3-phase PMSM. It is worth noting that no extra hardware equipment is required to implement the proposed method.展开更多
This work develops 2-Phenyl-1H-imidazole-1-sulfonate(PHIS)as a multi-functional electrolyte additive for H2O/HF scavenging and film formation to improve the high temperature performance of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_...This work develops 2-Phenyl-1H-imidazole-1-sulfonate(PHIS)as a multi-functional electrolyte additive for H2O/HF scavenging and film formation to improve the high temperature performance of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/graphite batteries.After 450 cycles at room temperature(25℃),the discharge capacity retentions of batteries with blank and PHIS-containing electrolyte are 56.03%and 94.92%respectively.After 230 cycles at high temperatures(45℃),their values are 75.30%and 88.38%respectively.The enhanced electrochemical performance of the batteries with PHIS-containing electrolyte is supported by the spectroscopic characterization and theoretical calculations.It is demonstrated that this PHIS electrolyte additive can facilitate the construction of the electrode interface films,remove the H2O/HF in the electrolyte,and improve the electrochemical performance of the batteries.This work not only develops a sulfonate-based electrolyte but also can stimulate new ideas of functional additives to improve the battery performance.展开更多
With the continued downscaling of complementary metal-oxide-semiconductor field effect transistor dimensions, high-dielectric constant （high-k） gate materials, as alternatives to SiO2, have been extensively investig...With the continued downscaling of complementary metal-oxide-semiconductor field effect transistor dimensions, high-dielectric constant （high-k） gate materials, as alternatives to SiO2, have been extensively investigated. Hf （Zr）-based high-k gate dielectric thin films have been regarded as the most promising candidates for high-k gate dielectric according to the International Technology Roadmap for Semiconductor due to their excellent physical properties and performance. This paper reviews the recent progress on Hf （Zr）-based high-k gate dielectrics based on PVD （physical vapor deposition） process. This article begins with a survey of various methods developed for generating Hf （Zr）-based high-k gate dielectrics, and then mainly focuses on microstructure, synthesis, characterization, formation mechanisms of interfacial layer, and optical properties of Hf （Zr）-based high-k gate dielectrics. Finally, this review concludes with personal perspectives towards future research on Hf （Zr）-based high-k gate dielectrics.展开更多
The NiAl-28Cr-5.85Mo-0.15Hf alloy was prepared by high-pressure die casting (HPDC) and subsequent hot isostatic pressing(HIP), and tested for compressible strength and fracture behavior at 300-1 373 K. The results sho...The NiAl-28Cr-5.85Mo-0.15Hf alloy was prepared by high-pressure die casting (HPDC) and subsequent hot isostatic pressing(HIP), and tested for compressible strength and fracture behavior at 300-1 373 K. The results show that the elevated temperature 0.2% compressible yield strength as well as the room-temperature compressible fracture strain of as-HIP alloy are larger than those of the same alloy prepared by directional solidification (DS). It suggests that the fine structures with a homogeneous distribution of fine Cr (Mo) and Hf-rich phase created by high-pressure die casting lead to these improvements.展开更多
The rapid development of Internet of Things(IoT)technology has made previously unavailable data available,and applications can take advantage of device data for people to visualize,explore,and build complex analyses.A...The rapid development of Internet of Things(IoT)technology has made previously unavailable data available,and applications can take advantage of device data for people to visualize,explore,and build complex analyses.As the size of the network and the number of network users continue to increase,network requests tend to aggregate on a small number of network resources,which results in uneven load on network requests.Real-time,highly reliable network file distribution technology is of great importance in the Internet of Things.This paper studies real-time and highly reliable file distribution technology for large-scale networks.In response to this topic,this paper studies the current file distribution technology,proposes a file distribution model,and proposes a corresponding load balancing method based on the file distribution model.Experiments show that the system has achieved real-time and high reliability of network transmission.展开更多
Based on the analyses of aluminum melt flow, solidification, heat transfer during the process of twin-roll casting, a coupling mathematical model of aluminum thin-gauge high-speed casting was developed, which included...Based on the analyses of aluminum melt flow, solidification, heat transfer during the process of twin-roll casting, a coupling mathematical model of aluminum thin-gauge high-speed casting was developed, which included the casting roller shell. At the same time, Galerkin method was adopted to solve the coupling model. The fluid field and temperature field of aluminum melt in casting zone, the temperature field and thermal stress field of roller shells were simulated by the coupling model. When the casting velocity is 7m/min, and the thickness of strip is 2mm, the circumfluent area comes into being in the casting zone, and the mushy zone dominates the casting zone, while the temperature of melt decreases rapidly as it approaches the rollers. The temperature of the roller shell varies periodically with the rotation of roller, and reaches the highest temperature in the casting zone, while the temperature of roller shell decreases gradually as it leaves the casting zone. The difference of thermal stress between the inner surface and outer surface of the roller shell is very large, and the outer surface suffers tensile-compressive stress.展开更多
1 Introduction The short-lived 182Hf-182W system is generally acknowledged as the best chronometer of metal-silicate segregation that occurred during the early evolution of asteroids and terrestrial planets due to its...1 Introduction The short-lived 182Hf-182W system is generally acknowledged as the best chronometer of metal-silicate segregation that occurred during the early evolution of asteroids and terrestrial planets due to its following properties:(1)Hf-W fractionation commonly occurs during metal-silicate differentiation;(2)Both Hf and W are highly refractory elements,therefore most bulk展开更多
This paper proposes the design and development of a novel, portable and low-cost intelligent electronic device (IED) for real-time monitoring of high frequency phenomena in CENELEC PLC band. A high speed floating-poin...This paper proposes the design and development of a novel, portable and low-cost intelligent electronic device (IED) for real-time monitoring of high frequency phenomena in CENELEC PLC band. A high speed floating-point digital signal processor (DSP) along with 4 MSPS analog-to-digital converter (ADC) is used to develop the intelligent electronic device. An optimized algorithm to process the analog signal in real-time and to extract the meaningful result using signal processing techniques has been implemented on the device. A laboratory environment has setup with all the necessary equipment including the development of the load model to evaluate the performance of the IED. Smart meter and concentrator is also connected to the low voltage (LV) network to monitor the PLC communication using the IED. The device has been tested in the laboratory and it has produced very promising results for time domain as well as frequency domain analysis. Those results imply that the IED is fully capable of monitoring high frequency disturbances in CENELEC PLC band.展开更多
Starting from the background of the"Double High Plan"in conjunction with the role of personnel file management in advancing the"Double High Plan",this paper analyzes the current status of personnel...Starting from the background of the"Double High Plan"in conjunction with the role of personnel file management in advancing the"Double High Plan",this paper analyzes the current status of personnel file management in higher vocational colleges and the necessity of personnel management in higher vocational colleges,and explores the effective measures to strengthen the informatization of personnel files management to make it more reasonable,standardized and informatized.展开更多
A truncated shell model approach is applied to the description of high-spinstates for <sup>162</sup>Hf and <sup>164</sup>Hf isotopes.The backbends of the moment of inertia are repro-duced well ...A truncated shell model approach is applied to the description of high-spinstates for <sup>162</sup>Hf and <sup>164</sup>Hf isotopes.The backbends of the moment of inertia are repro-duced well by the calculation.The results show that the approach is able to investigatethe yrast states of nuclei in rare earth region.展开更多
文摘The second generation single crystal superalloy DD6 with 0.10%Hf and 0.34%Hf （in mass fraction） was subjected to high-cycle fatigue （HCF） loading at temperatures of 700 ℃ in ambient atmosphere. SEM was used to determine the initiation site and the failure mechanism. Evolution of the microstructure was investigated by TEM observation. The results show that fatigue limit of DD6 alloy with 0.34%Hf is a little smaller than that of the alloy with 0.10%Hf. The fatigue cracks initiated on the surface or near the surface of the specimens. The crack would propagate along { 111 } octahedral slip planes, rather than perpendicular to the loading axis of specimen. Typical fatigue striation formed in steady propagation of fatigue crack. The fracture mechanisms of the high cycle fatigue of DD6 alloys with 0.10%Hf and 0.34%Hf are quasi-cleavage fracture. Different types of dislocation structures were developed during high cycle fatigue deformation.
基金supported by the National Key Research and Development Program of China from the Ministry of ScienceandTechnologyofChina(No.2017YFC0601301)the National Natural Science Foundation of China(41502214,41230207 and 41572190)+5 种基金the Outlay Research Fund of Institute of Geology,Chinese Academy of Geological Sciences(J1706)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(XDB18020203)the CPSF-CAS Joint Foundation for Excellent Postdoctoral Fellows(Grant no.2015LH0049)the China Postdoctoral Foundation funded project(2016M590990)the Key Research Program of Frontier Sciences,CAS(QYZDJSSW-SYS012)China Geological Survey(12120115069601)
文摘Voluminous granitoids are widely distributed in the Langshan region,northeast of the Alxa block,and record the evolutionary processes of the southern Central Asian Orogenic Belt.The Dabashan pluton was emplaced into the Paleoproterozoic Diebusige complex.Early Carboniferous zircon LA-ICP MS U-Pb ages were from 327 Ma to 346 Ma.The Dabashan pluton can be classified as monzogranite and syenogranite,and exhibits high K2 O contents and K2 O/Na2 O ratios,which reveal a high-K calc-alkaline nature.The samples display strongly fractionated REE patterns,and are enriched in large ion lithophile elements(LILE)relative to high field strength elements(HFSE).The Dabashan plutons display unusually high Ba(823–2817 ppm)and Sr(166–520 ppm)contents and K/Rb ratios(315–627),but low Rb/Ba ratios(0.02–0.14),and exhibit fertile zircon Hf isotopic compositions[εHf(t)=-14 to-20],which are comparable to those of typical high Ba–Sr granitoids.Based on the geochemical compositions of the samples,we suggest that subducted sediments and ancient crustal materials both played important roles in their generation.Basaltic melts were derived from partial melting of subcontinental lithophile mantle metasomatized by subducted sediment-related melts with residual garnet in the source,which caused partial melting of ancient lower crust.Magmas derived from underplating ascended and emplaced in the middle–upper crust at different depths.The resultant magmas experienced some degree of fractional crystallization during their ascent.Given these geochemical characteristics,together with regional tectonic,magmatic,and structure analysis data,an active continental margin environment is proposed for the generation of these rocks.
文摘In this letter,a kind of associated synchronization algorithm which is suitable for HF(High Frequency) broadband OFDM(Orthogonal Frequency Division Multiplexing) system is presented based on describing and constructing the GMW(Gorden,Mills and Welch) sequence. The algorithm is based on the Schmidl and Minn's symbol timing principle,the constructed GMW sequence is trans-mitted and disposed,and the synchronization is adjudicated using the correlation of GMW sequence. The simulation result indicates that this algorithm has high performance synchronization ability under the low SNR(Signal to Noise Ratio) at two different kinds of channel models.
基金supported in part by the Jiangsu Carbon Peak Carbon Neutralization Science and Technology Innovation Special Fund under Grant BE2022032-1National Natural Science Foundation of China under Grant 52277035, Grant 51937006 and Grant 51907028the “SEU Zhishan Young Scholars” Program of Southeast University。
文摘Inter-turn fault is a serious stator winding short-circuit fault of permanent magnet synchronous machine(PMSM). Once it occurs, it produces a huge short-circuit current that poses a great risk to the safe operation of PMSM. Thus, an inter-turn short-circuit fault(ITSCF) diagnosis method based on high frequency(HF) voltage residual is proposed in this paper with proper HF signal injection. First, the analytical models of PMSM after the ITSCF are deduced. Based on the model, the voltage residual at low frequency(LF) and HF can be obtained. It is revealed that the HF voltage residual has a stronger ITSCF detection capability compared to the LF voltage residual. To obtain optimal fault signature, a 3-phase symmetrical HF voltage is injected into the machine drive system, and the HF voltage residuals are extracted. The fault indicator is defined as the standard deviation of the 3-phase HF voltage residuals. The effectiveness of the proposed ITSCF diagnosis method is verified by experiments on a triple 3-phase PMSM. It is worth noting that no extra hardware equipment is required to implement the proposed method.
基金financially supported by the Scientific and Technological Plan Projects of Guangzhou City(202103040001)。
文摘This work develops 2-Phenyl-1H-imidazole-1-sulfonate(PHIS)as a multi-functional electrolyte additive for H2O/HF scavenging and film formation to improve the high temperature performance of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/graphite batteries.After 450 cycles at room temperature(25℃),the discharge capacity retentions of batteries with blank and PHIS-containing electrolyte are 56.03%and 94.92%respectively.After 230 cycles at high temperatures(45℃),their values are 75.30%and 88.38%respectively.The enhanced electrochemical performance of the batteries with PHIS-containing electrolyte is supported by the spectroscopic characterization and theoretical calculations.It is demonstrated that this PHIS electrolyte additive can facilitate the construction of the electrode interface films,remove the H2O/HF in the electrolyte,and improve the electrochemical performance of the batteries.This work not only develops a sulfonate-based electrolyte but also can stimulate new ideas of functional additives to improve the battery performance.
基金the support from the National Major Project of Fundamental Research:Nanomaterials and Nanostructures(Grant No.2005CB623603)the National Natural Science Foundation of China(Grant No.10674138)the Special Fund for President Scholarship,Chinese Academy of Sciences.
文摘With the continued downscaling of complementary metal-oxide-semiconductor field effect transistor dimensions, high-dielectric constant （high-k） gate materials, as alternatives to SiO2, have been extensively investigated. Hf （Zr）-based high-k gate dielectric thin films have been regarded as the most promising candidates for high-k gate dielectric according to the International Technology Roadmap for Semiconductor due to their excellent physical properties and performance. This paper reviews the recent progress on Hf （Zr）-based high-k gate dielectrics based on PVD （physical vapor deposition） process. This article begins with a survey of various methods developed for generating Hf （Zr）-based high-k gate dielectrics, and then mainly focuses on microstructure, synthesis, characterization, formation mechanisms of interfacial layer, and optical properties of Hf （Zr）-based high-k gate dielectrics. Finally, this review concludes with personal perspectives towards future research on Hf （Zr）-based high-k gate dielectrics.
基金Project (05YB31) supported by the Scientific Research Initial Foundation for Doctor of Shenyang Institute of Aeronautical Engineering,China
文摘The NiAl-28Cr-5.85Mo-0.15Hf alloy was prepared by high-pressure die casting (HPDC) and subsequent hot isostatic pressing(HIP), and tested for compressible strength and fracture behavior at 300-1 373 K. The results show that the elevated temperature 0.2% compressible yield strength as well as the room-temperature compressible fracture strain of as-HIP alloy are larger than those of the same alloy prepared by directional solidification (DS). It suggests that the fine structures with a homogeneous distribution of fine Cr (Mo) and Hf-rich phase created by high-pressure die casting lead to these improvements.
基金This work was supported by National Key Research&Development Plan of China under Grant 2016QY05X1000National Natural Science Foundation of China under Grant No.61771166CERNET Innovation Project(NGII20170412).
文摘The rapid development of Internet of Things(IoT)technology has made previously unavailable data available,and applications can take advantage of device data for people to visualize,explore,and build complex analyses.As the size of the network and the number of network users continue to increase,network requests tend to aggregate on a small number of network resources,which results in uneven load on network requests.Real-time,highly reliable network file distribution technology is of great importance in the Internet of Things.This paper studies real-time and highly reliable file distribution technology for large-scale networks.In response to this topic,this paper studies the current file distribution technology,proposes a file distribution model,and proposes a corresponding load balancing method based on the file distribution model.Experiments show that the system has achieved real-time and high reliability of network transmission.
文摘Based on the analyses of aluminum melt flow, solidification, heat transfer during the process of twin-roll casting, a coupling mathematical model of aluminum thin-gauge high-speed casting was developed, which included the casting roller shell. At the same time, Galerkin method was adopted to solve the coupling model. The fluid field and temperature field of aluminum melt in casting zone, the temperature field and thermal stress field of roller shells were simulated by the coupling model. When the casting velocity is 7m/min, and the thickness of strip is 2mm, the circumfluent area comes into being in the casting zone, and the mushy zone dominates the casting zone, while the temperature of melt decreases rapidly as it approaches the rollers. The temperature of the roller shell varies periodically with the rotation of roller, and reaches the highest temperature in the casting zone, while the temperature of roller shell decreases gradually as it leaves the casting zone. The difference of thermal stress between the inner surface and outer surface of the roller shell is very large, and the outer surface suffers tensile-compressive stress.
基金supported by funds from the National Natural Science Foundation of China (No. 41521062, 41490631)
文摘1 Introduction The short-lived 182Hf-182W system is generally acknowledged as the best chronometer of metal-silicate segregation that occurred during the early evolution of asteroids and terrestrial planets due to its following properties:(1)Hf-W fractionation commonly occurs during metal-silicate differentiation;(2)Both Hf and W are highly refractory elements,therefore most bulk
文摘This paper proposes the design and development of a novel, portable and low-cost intelligent electronic device (IED) for real-time monitoring of high frequency phenomena in CENELEC PLC band. A high speed floating-point digital signal processor (DSP) along with 4 MSPS analog-to-digital converter (ADC) is used to develop the intelligent electronic device. An optimized algorithm to process the analog signal in real-time and to extract the meaningful result using signal processing techniques has been implemented on the device. A laboratory environment has setup with all the necessary equipment including the development of the load model to evaluate the performance of the IED. Smart meter and concentrator is also connected to the low voltage (LV) network to monitor the PLC communication using the IED. The device has been tested in the laboratory and it has produced very promising results for time domain as well as frequency domain analysis. Those results imply that the IED is fully capable of monitoring high frequency disturbances in CENELEC PLC band.
文摘Starting from the background of the"Double High Plan"in conjunction with the role of personnel file management in advancing the"Double High Plan",this paper analyzes the current status of personnel file management in higher vocational colleges and the necessity of personnel management in higher vocational colleges,and explores the effective measures to strengthen the informatization of personnel files management to make it more reasonable,standardized and informatized.
文摘A truncated shell model approach is applied to the description of high-spinstates for <sup>162</sup>Hf and <sup>164</sup>Hf isotopes.The backbends of the moment of inertia are repro-duced well by the calculation.The results show that the approach is able to investigatethe yrast states of nuclei in rare earth region.
