China's High Performance Computer Standard Commission was established on March 28, 2007, under the guidance of the Science and Technology Bureau of the Ministry of Information Industry. It will prepare relevan... China's High Performance Computer Standard Commission was established on March 28, 2007, under the guidance of the Science and Technology Bureau of the Ministry of Information Industry. It will prepare relevant professional standards on high performance computers to break through the monopoly in the field by foreign manufacturers and vendors.……展开更多
High performance computers provide strategic computing power in the construction of national economy and defense, and become one of symbols of the country＇s overall strength. Over 30 years, with the supports of gover...High performance computers provide strategic computing power in the construction of national economy and defense, and become one of symbols of the country＇s overall strength. Over 30 years, with the supports of governments, the technology of high performance computers is in the process of rapid development, during which the computing performance increases nearly 3 million times and the processors number expands over 10 hundred thousands times. To solve the critical issues related with parallel efficiency and scalability, scientific researchers pursued extensive theoretical studies and technical innovations. The paper briefly looks back the course of building high performance computer systems both at home and abroad, and summarizes the significant breakthroughs of international high performance computer technology. We also overview the technology progress of China in the area of parallel computer architecture, parallel operating system and resource management, parallel compiler and performance optimization, environment for parallel programming and network computing. Finally, we examine the challenging issues, ＂memory wall＂, system scalability and ＂power wall＂, and discuss the issues of high productivity computers, which is the trend in building next generation high performance computers.展开更多
High performance computer （HPC） is a complex huge system, of which the architecture design meets increasing difficulties and risks. Traditional methods, such as theoretical analysis, component-level simulation and s...High performance computer （HPC） is a complex huge system, of which the architecture design meets increasing difficulties and risks. Traditional methods, such as theoretical analysis, component-level simulation and sequential simulation, are not applicable to system-level simulations of HPC systems. Even the parallel simulation using large-scale parallel machines also have many difficulties in scalability, reliability, generality, as well as efficiency. According to the current needs of HPC architecture design, this paper proposes a system-level parallel simulation platform： ArchSim. We first introduce the architecture of ArchSim simulation platform which is composed of a global server （GS）, local server agents （LSA） and entities. Secondly, we emphasize some key techniques of ArchSim, including the synchronization protocol, the communication mechanism and the distributed checkpointing/restart mechanism. We then make a synthesized test of some main performance indices of ArchSim with the phold benchmark and analyze the extra overhead generated by ArchSim. Finally, based on ArchSim, we construct a parallel event-driven interconnection network simulator and a system-level simulator for a small scale HPC system with 256 processors. The results of the performance test and HPC system simulations demonstrate that ArchSim can achieve high speedup ratio and high scalability on parallel host machine and support system-level simulations for the architecture design of HPC systems.展开更多
With supercomputers developing towards exascale, the number of compute cores increases dramatically, making more complex and larger-scale applications possible. The input/output （I/O） requirements of large-scale app...With supercomputers developing towards exascale, the number of compute cores increases dramatically, making more complex and larger-scale applications possible. The input/output （I/O） requirements of large-scale applications, workflow applications, and their checkpointing include substantial bandwidth and an extremely low latency, posing a serious challenge to high performance computing （HPC） storage systems. Current hard disk drive （HDD） based underlying storage systems are becoming more and more incompetent to meet the requirements of next-generation exascale supercomputers. To rise to the challenge, we propose a hierarchical hybrid storage system, on-line and near-line file system （ONFS）. It leverages dynamic random access memory （DRAM） and solid state drive （SSD） in compute nodes, and HDD in storage servers to build a three-level storage system in a unified namespace. It supports portable operating system interface （POSIX） semantics, and provides high bandwidth, low latency, and huge storage capacity. In this paper, we present the technical details on distributed metadata management, the strategy of memory borrow and return, data consistency, parallel access control, and mechanisms guiding downward and upward migration in ONFS. We implement an ONFS prototype on the TH-1A supercomputer, and conduct experiments to test its I/O performance and scalability. The results show that the bandwidths of single-thread and multi-thread ＇read＇/＇write＇ are 6-fold and 5-fold better than HDD-based Lustre, respectively. The I/O bandwidth of data-intensive applications in ONFS can be 6.35 timcs that in Lustre.展开更多
This study begins with the fabrication and simulation of high-performance back-illuminated AlGaN-based solar-blind ultraviolet(UV)photodetectors.Based on the photodetectors,a low-noise,high-gain UV detection system ci...This study begins with the fabrication and simulation of high-performance back-illuminated AlGaN-based solar-blind ultraviolet(UV)photodetectors.Based on the photodetectors,a low-noise,high-gain UV detection system circuit is designed and fabricated,enabling the detection,acquisition,and calibration of weak solar-blind UV signals.Experimental results demonstrate that under zero bias conditions,with a UV light power density of 3.45μW/cm^(2) at 260 nm,the sample achieves a peak responsivity(R)of 0.085 A·W^(−1),an external quantum efficiency(EQE)of 40.7%,and a detectivity(D^(*))of 7.46×10^(12) cm·Hz^(1/2)·W^(−1).The system exhibits a bandpass characteristic within the 240–280 nm wavelength range,coupled with a high signal-to-noise ratio(SNR)of 39.74 dB.展开更多
MnCO_(3)represents a potentially high-capacity and low-cost anode candidate to replace graphite for enhancing energy density of commercial lithium-ion batteries,but it suffers from poor electrical conductivity and ser...MnCO_(3)represents a potentially high-capacity and low-cost anode candidate to replace graphite for enhancing energy density of commercial lithium-ion batteries,but it suffers from poor electrical conductivity and serious volumetric change,largely hindering its practical applications.展开更多
ZFJ Textile Machinery Co.,Ltd.,established in 1949,is a key enterprise directly managed by China Hi-Tech Group Corporation and falls under the jurisdiction of China National Machinery Industry Corporation Limited(Sino...ZFJ Textile Machinery Co.,Ltd.,established in 1949,is a key enterprise directly managed by China Hi-Tech Group Corporation and falls under the jurisdiction of China National Machinery Industry Corporation Limited(Sinomach).As a leading enterprise in the textile machinery manufacturing industry,ZFJ is dedicated to providing global customers with complete equipment solutions covering the entire industry chain.During this exhibition,ZFJ primarily highlights three key features:"high-performance fibers,green fibers,and intelligent equipment,"with a focus on showcasing nine types of products,spanning various textile equipment categories,including chemical fiber,specialty fiber,nonwoven,sizing,and dyeing machinery.展开更多
Lithium/fluorinated carbon(Li/CF_(x))batteries are greatly limited in their applications mostly due to poor rate performances.In this study,N,P co-doped biomass carbon was synthesized using melamine and phytic acid as...Lithium/fluorinated carbon(Li/CF_(x))batteries are greatly limited in their applications mostly due to poor rate performances.In this study,N,P co-doped biomass carbon was synthesized using melamine and phytic acid as doping sources,and the resulting product was then utilized as a precursor for CF_(x).The resulting fluorinated biomass carbon has a high degree of fluorination,exceeding the specific capacity of commercial fluorinated graphite while also demonstrating exceptional performance at high discharge rates.During the fluorination process,N,P-containing functional groups were removed from the crystalline lattice in the basal plane.This facilitates the formation of a defect-rich carbon matrix,enhancing the F/C ratio by improving the fluorinated active sites and obtaining more highly active semi-ionic bonds.Additionally,the abundant defects and porous structure promote Li^(+)diffusion.Density functional theory calculations indicated that doping modification effectively reduces the energy barrier for Li+migration,enhancing Li+transport efficiency.The prepared CF_(x)delivers material with a maximum specific capacity of 919 mAh·g^(-1),while maintaining a specific capacity of 702 mAh·g^(-1)at a high discharge current density of 20C(with a capacity retention rate of 76.4%).In this study,fluorinated N,P co-doped biomass carbon,exhibiting ultrahigh capacity and high-rate performance,was prepared for the first time,which can potentially advance the commercialization of CF_(x).展开更多
A high-performance liquid chromatography(HPLC)method has been developed using a CAPCELL PAK ADME(150 mm×4.6 mm,5μm)as analytical column and a gradient elution with 15 min using acetonitrile and 0.1%(in volume fr...A high-performance liquid chromatography(HPLC)method has been developed using a CAPCELL PAK ADME(150 mm×4.6 mm,5μm)as analytical column and a gradient elution with 15 min using acetonitrile and 0.1%(in volume fraction)phosphoric acid water(pH=2.2)as the mobile phase.Three active substances in cosmetics were quantitatively detected simultaneously at a detection wavelength of 265 nm.The linear ranges of β-nicotinamide mononucleotides,ergothioneine and nicotinamide are 10~200 mg/L,5~100 mg/L and 5~100 mg/L respectively and the detection limits of three components are 3.0 mg/L,1.5 mg/L and 1.5 mg/L respectively.The recovery rate is 97.1~104.9%,with RSD≤2.0%.The method was applied to quantitative analysis of five samples of cosmetics toner,lotion,cream,essence and gel and three samples of raw materials.The results showed that the results of β-nicotinamide mononucleotide and ergothioneine in five cosmetics were consistent with the product label,while nicotinamide was inconsistent with the label.The purity of the three raw material samples was 99.5%,99.7% and 100.8%respectively.This method offers high precision,accuracy and short analysis time,making it a reliable approach for studying three active ingredients in cosmetics and suitable for quality control of related functional ingredients.展开更多
Anode active materials involving transition metal oxides and sulfides are of great significance for high energy density lithium-ion batteries(LIBs),but the huge volume expansion and inferior electronic conductivity up...Anode active materials involving transition metal oxides and sulfides are of great significance for high energy density lithium-ion batteries(LIBs),but the huge volume expansion and inferior electronic conductivity upon cycling critically constrain their further application.Herein,from a new perspective,a highly conductive and stable 3D flexible composite current collector is rationally designed by facilely electrodepositing metallic Ni thin layer onto the carbon cloth(CC/Ni),which endows the supported active materials with exceptional electronic conductivity and structural stability.In addition,the homogeneously distributed metallic Ni protrusions external CC can strongly bond with the active components,ensuring the structural integrity of electrodes upon cycling.More importantly,the 3D network structure with large specific surface area provides abundant space to alleviate the volume expansion and more active sites for electrochemical reactions.Therefore,taking Ni_(3)S_(2)nanosheet(Ni_(3)S_(2)NS)anode as an example,the prepared Ni_(3)S_(2)NS@CC/Ni electrode shows a high specific capacity of 2.32 mAh/cm^(2)at 1mA/cm^(2)and high capacity retention of 1.68 mAh/cm^(2)at a high rate of 8mA/cm^(2).This study provides a universal approach to obtain highly conductive and stable 3D flexible current collectors towards high performance metal-ion batteries beyond LIBs.展开更多
The weak interlayer van der Waals(vdW) interactions in two-dimensional(2D) vdW materials enable sliding ferroelectricity as an effective strategy for modulating their intrinsic properties. In this work, we systematica...The weak interlayer van der Waals(vdW) interactions in two-dimensional(2D) vdW materials enable sliding ferroelectricity as an effective strategy for modulating their intrinsic properties. In this work, we systematically investigate the influence of interlayer sliding on the electronic behavior of PtSe_(2) using density functional theory(DFT) calculations. Our results demonstrate that interlayer sliding induces a pronounced photocurrent spanning the short-wavelength infrared to visible spectral ranges. Remarkably, under an applied gate voltage, the sliding ferroelectric PtSe_(2) exhibits anomalously enhanced photovoltaic performance and an ultrahigh extinction ratio.Transmission spectral analysis reveals that this phenomenon originates from band structure modifications driven by energy-level transitions. Furthermore, the observed photocurrent enhancement via sliding ferroelectricity demonstrates universality across diverse platinum-based optoelectronic devices. This study introduces a novel paradigm for tailoring the intrinsic characteristics of 2D vdW semiconductors, expanding the design space for next-generation ferroelectric materials in advanced optoelectronic applications.展开更多
With the most advanced and sophisticated technologies and equipment,NYBELT is one of the largest manufacturers of flat transmission belts in the world.Under the Certified Quality,Environment,Occupational Health&Sa...With the most advanced and sophisticated technologies and equipment,NYBELT is one of the largest manufacturers of flat transmission belts in the world.Under the Certified Quality,Environment,Occupational Health&Safety,and Energy Standardized ISO Management System,NYBELT can produce all kinds of flat transmission belts,roller coverings and conveyor belts applicable to textile,printing&packaging,electronics and other industries.Due to the superior quality and the reasonable prices,we have become well known in providing high quality belting products and excellent service to customers all over the world.Our success in the past gives us the confidence to look into the future with great expectations.展开更多
Maintaining stable high temperatures under pressure remains a challenge in high-pressure,high-temperature experiments using multi-anvil presses(MAPs).Temperature fluctuations exceeding 10℃ at high pressures are commo...Maintaining stable high temperatures under pressure remains a challenge in high-pressure,high-temperature experiments using multi-anvil presses(MAPs).Temperature fluctuations exceeding 10℃ at high pressures are common and particularly problematic with LaCrO_(3) heaters,which can experience significant power fluctuations and even failure due to substantial resistance changes—an issue conventional thyristorcontrolled heating systems cannot effectively manage.To address this limitation,we have developed the Multi-Anvil Stable Temperature controller(MASTer),a high-performance heating system optimized for MAP experiments.MASTer enables precise,high-speed measurement of heating parameters and power output control,incorporating a gentle regulation strategy to enhance stability.It ensures consistent heating across various heater types,including LaCrO_(3),with power fluctuations limited to±0.1 W and temperature fluctuations to within±2℃ in most cases.The design,operating principles,user interface,functionality,and performance of the heating system are discussed in detail.展开更多
[Objectives]To extract and purify perfluoroalkyl and polyfluoroalkyl substances(PFAS)from aquatic products and determine the optimal pretreatment conditions.[Methods]The QuEChERS method was employed for the extraction...[Objectives]To extract and purify perfluoroalkyl and polyfluoroalkyl substances(PFAS)from aquatic products and determine the optimal pretreatment conditions.[Methods]The QuEChERS method was employed for the extraction and purification of PFAS in aquatic products.The detection of PFAS was carried out using liquid chromatography-tandem mass spectrometry(LC-MS/MS)in ESI negative ion mode with multiple reaction monitoring(MRM),and quantification was performed using the external standard method.By optimizing instrument parameters such as ion source temperature,spray voltage,and collision energy,high selectivity and sensitivity of the detection were ensured.[Results]The established calibration curves for 28 PFAS compounds compounds,covering a range of 0.02 to 20 ng/mL,demonstrated excellent linearity.Spike recovery tests yielded limits of detection(LOD)between 0.02 and 0.5μg/kg for the 28 PFAS compounds compounds,with recovery rates ranging from 72.2%to 113.0%.[Conclusions]The method established in this study demonstrates excellent linearity,and is accurate,reliable,efficient,simple,and rapid.It possesses considerable practical applicability and can be used for the quality and risk assessment of 28 PFAS compounds compounds in aquatic products,indicating high practical utility.展开更多
This study aims to assess the comprehensive strengthening effect of a steel-ultra high performance concrete(UHPC)composite strengthening method.The axial force-moment interaction curve(N-M curve)was calculated in a no...This study aims to assess the comprehensive strengthening effect of a steel-ultra high performance concrete(UHPC)composite strengthening method.The axial force-moment interaction curve(N-M curve)was calculated in a novel way,using cross-sectional strains at ultimate states as well as real-time stress measurements for each material.The enclosed area of the N-M curve was defined as a comprehensive performance index for the system.We validate our approach with comparisons to numerical modeling and full-scale four-point bending experiments.Additionally,strengthening effects were compared for different sagging and hogging moments based on material stress responses,and the impact of various strengthening parameters was analyzed.We find that the N-M curve of the strengthened cross-section envelops that of the un-strengthened cross-section.Notably,improvements in flexural capacity are greater under sagging moments during the large eccentric failure stage,and greater under hogging moments during the small eccentric failure stage.This discrepancy is attributed to the strength utilization of strengthening materials.These findings provide a reference for understanding the strengthening effects and parameters of steel-UHPC composite.展开更多
Ceramic cores are key to forming a cooling structure within the hollow blade cavities.The use of stereolithography(SL)3D printing technology eliminates the need for moulds,facilitating the preparation of complex-shape...Ceramic cores are key to forming a cooling structure within the hollow blade cavities.The use of stereolithography(SL)3D printing technology eliminates the need for moulds,facilitating the preparation of complex-shaped ceramic cores.In this study,silica-based ceramic cores incorporating nano-3YSZ(3mol.% yttria stabilised zirconia)and micron-sized Y_(2)O_(3) were prepared via SL 3D printing ceramic technology to promote the formation of cristobalite and ZrSiO_(4),thereby improving the high-temperature properties.The flexural strength at 25℃ and 1,500℃,deflection at 1,500℃,shrinkage rate,and porosity of the core samples sintered at different temperatures(1,170℃,1,185℃,1,200℃,1,215℃,and 1,230℃)were tested and investigated.The mechanism underlying the high temperature performance of the cores was elucidated through analysis of cross-sectional morphology,element distribution,and phase constitution of the samples.As the sintering temperature increases,the shrinkage and flexural strength at 25℃ of the core rise,while the open porosity and deflection at 1,500℃ decrease.When the sintering temperature reaches 1,200℃ or higher,the 1,500℃ flexural strength can be measured,which increases as the sintering temperature rises.The core exhibits excellent creep resistance when sintered at temperatures of 1,200℃ and above.Considering the comprehensive performance requirements for the core,the sintering temperature of 1,200℃ was selected.At the sintering temperature of 1,200℃,the core exhibits shrinkage rates of 3.76%(X),3.38%(Y),and 3.95%(Z),alongside a flexural strength of 9.01 MPa at 25℃ and 32.15 MPa at 1,500℃,and an open porosity of 26.39%.The deflection of the core at 1,500℃ is 0.15 mm,which helps to maintain the dimensional stability of the ceramic core during casting.XRD results indicate that samples fractured after 25℃ flexural strength test still contain amorphous quartz glass,alongside substantial quantities of yttria stabilized zirconia and Y_(2)O_(3).Samples fractured after 1,500℃ flexural strength test exhibit significant crystallisation of amorphous quartz glass into cristobalite,with silica and 3YSZ combining to form ZrSiO_(4).Y_(2)O_(3) as a network modifier of the glass network destroys the bridging oxygen in the silica-oxygen bond,thereby reducing the energy required for glass crystallisation and promoting the crystallisation reaction of quartz glass to form cristobalite.In addition,nano-3YSZ combines with SiO_(2) at high temperatures to form ZrSiO_(4).Since cristobalite and ZrSiO_(4) are crystals,both of them have strong creep resistance,thus improving the high temperature flexural strength and deformation resistance of the ceramic cores.展开更多
Influences of admixtures on the workability and strength of high performance concrete （HPC） are in- vestigated. The types of investigated admixtures include naphthalene series high range water reducing agent, polyca...Influences of admixtures on the workability and strength of high performance concrete （HPC） are in- vestigated. The types of investigated admixtures include naphthalene series high range water reducing agent, polycarboxlic series high range water reduce agent and sodium sulfate hardening accelerating agent. Two kinds of curing condition, namely steam curing condition and standard curing condition, are adopted. The result shows that HPC, added with polycarboxlic series of high performance water reducer, has high workability and strength, while sodium sulfate accelerating agent causes poor workability and low strength. Thus for vapor-cured HPC and its formulations, naphthalene series high range water reducing agent with less sodium sulfate should be given pri- ority. Therefore, the differences of curing conditions should be considered when selecting HPC admixtures.展开更多
Abstract： In the presem study, we simultaneously quantified the levels of monoamine neurotransmitters （MANTs） and their metabolites （levodopa, norepinephrine, epinephrine, dopamine, 5-HT, 3,4-dihydroxyphenylacetic...Abstract： In the presem study, we simultaneously quantified the levels of monoamine neurotransmitters （MANTs） and their metabolites （levodopa, norepinephrine, epinephrine, dopamine, 5-HT, 3,4-dihydroxyphenylacetic acid, homovanillic acid and 5-hydroxyindole-3-acetic acid） in different brain subregions of rats using a newly developed simple, sensitive and selective high-performance liquid chromatography with fluorescence detection （HPLC-FLD） method. In this new HPLC-FLD method, analytes were directly extracted and separated without deriveatization step within 20 min. The FLD wavelength was set at 280 nm and 330 nm for excitation and emission, respectively. The analytes were separated on an Agilent Eclipse Plus Cls column （4.6 mm×150 mm, 5.0 μm） equipped with an Agilent XDB-C18 security guard column （4.6 mm×12.5 mm, 5.0 lam）, and the column temperature was maintained at 35 ℃. The mobile phase for elution was isocratic. The mobile phase consisted of citric acid buffer （50 mmol/L citric acid, 50 mmol/L sodium acetate, 0.5 mmol/L octane sulfonic acid sodium salt, 0.5 mmol/L Na2EDTA and 5 mmol/L triethylamine, pH 3.8） and methanol （90：10, v/v） at a flow rate of 1.0 mL/min. The detection limit （DL） was 0.9-23 nM for all the MANTs and their metabolites with a sample volume of 50 μL. The method was shown to be highly reproducible in terms of peak area （intraday, 0.08%-1.85% RSD, n = 5）. The simultaneous measurement of these MANTs and their metabolites improved our understanding of the neurochemistry in the central nervous system （CNS） in relation to different addictive drugs （methamphetamine, heroin and their mixture） in drug-addicted rat models.展开更多
Due to their biological and physiological importance,flavonoids receive considerable attention in the literature. Nowadays,high performance liquid chromatography（HPLC）is the most widely used analytical method.In thi...Due to their biological and physiological importance,flavonoids receive considerable attention in the literature. Nowadays,high performance liquid chromatography（HPLC）is the most widely used analytical method.In this review,we summarize the principle of the choice of HPLC column and mobile phase,discuss and compare the features of various detections such as UV,fluorescence detection,electrochemical detection,chemilummescence detection,UV-MS etc.Recent developments in HPLC including ultra-LC and miniaturization of LC（micro-LC,capillary-LC,and nano-LC）,are also discussed.展开更多
文摘 China's High Performance Computer Standard Commission was established on March 28, 2007, under the guidance of the Science and Technology Bureau of the Ministry of Information Industry. It will prepare relevant professional standards on high performance computers to break through the monopoly in the field by foreign manufacturers and vendors.……
基金The paper is partly supported by the National Natural Science Foundation of China under Grant No. 69933030. Acknowledgement We have to indicate with great regret that some excellent researches may not be mentioned in this paper because of our limited knowledge and the wide area related with high performance computer technology.
文摘High performance computers provide strategic computing power in the construction of national economy and defense, and become one of symbols of the country＇s overall strength. Over 30 years, with the supports of governments, the technology of high performance computers is in the process of rapid development, during which the computing performance increases nearly 3 million times and the processors number expands over 10 hundred thousands times. To solve the critical issues related with parallel efficiency and scalability, scientific researchers pursued extensive theoretical studies and technical innovations. The paper briefly looks back the course of building high performance computer systems both at home and abroad, and summarizes the significant breakthroughs of international high performance computer technology. We also overview the technology progress of China in the area of parallel computer architecture, parallel operating system and resource management, parallel compiler and performance optimization, environment for parallel programming and network computing. Finally, we examine the challenging issues, ＂memory wall＂, system scalability and ＂power wall＂, and discuss the issues of high productivity computers, which is the trend in building next generation high performance computers.
基金supported by the National High Technology Research and Development 863 Program of China under Grant No. 2007AA01Z117the National Basic Research 973 Program of China under Grant No.2007CB310900
文摘High performance computer （HPC） is a complex huge system, of which the architecture design meets increasing difficulties and risks. Traditional methods, such as theoretical analysis, component-level simulation and sequential simulation, are not applicable to system-level simulations of HPC systems. Even the parallel simulation using large-scale parallel machines also have many difficulties in scalability, reliability, generality, as well as efficiency. According to the current needs of HPC architecture design, this paper proposes a system-level parallel simulation platform： ArchSim. We first introduce the architecture of ArchSim simulation platform which is composed of a global server （GS）, local server agents （LSA） and entities. Secondly, we emphasize some key techniques of ArchSim, including the synchronization protocol, the communication mechanism and the distributed checkpointing/restart mechanism. We then make a synthesized test of some main performance indices of ArchSim with the phold benchmark and analyze the extra overhead generated by ArchSim. Finally, based on ArchSim, we construct a parallel event-driven interconnection network simulator and a system-level simulator for a small scale HPC system with 256 processors. The results of the performance test and HPC system simulations demonstrate that ArchSim can achieve high speedup ratio and high scalability on parallel host machine and support system-level simulations for the architecture design of HPC systems.
基金Project supported by the National Key Research and Development Program of China(No.2016YFB0200402)
文摘With supercomputers developing towards exascale, the number of compute cores increases dramatically, making more complex and larger-scale applications possible. The input/output （I/O） requirements of large-scale applications, workflow applications, and their checkpointing include substantial bandwidth and an extremely low latency, posing a serious challenge to high performance computing （HPC） storage systems. Current hard disk drive （HDD） based underlying storage systems are becoming more and more incompetent to meet the requirements of next-generation exascale supercomputers. To rise to the challenge, we propose a hierarchical hybrid storage system, on-line and near-line file system （ONFS）. It leverages dynamic random access memory （DRAM） and solid state drive （SSD） in compute nodes, and HDD in storage servers to build a three-level storage system in a unified namespace. It supports portable operating system interface （POSIX） semantics, and provides high bandwidth, low latency, and huge storage capacity. In this paper, we present the technical details on distributed metadata management, the strategy of memory borrow and return, data consistency, parallel access control, and mechanisms guiding downward and upward migration in ONFS. We implement an ONFS prototype on the TH-1A supercomputer, and conduct experiments to test its I/O performance and scalability. The results show that the bandwidths of single-thread and multi-thread ＇read＇/＇write＇ are 6-fold and 5-fold better than HDD-based Lustre, respectively. The I/O bandwidth of data-intensive applications in ONFS can be 6.35 timcs that in Lustre.
基金supported by the Director’s Fund for the‘Climbing Plan’of the National Space Science Centre of the Chinese Academy of Sciences(No.E2PD10011S)the National Engineering Research Centre for Mobile Private Networks Project(No.BJTU20221102).
文摘This study begins with the fabrication and simulation of high-performance back-illuminated AlGaN-based solar-blind ultraviolet(UV)photodetectors.Based on the photodetectors,a low-noise,high-gain UV detection system circuit is designed and fabricated,enabling the detection,acquisition,and calibration of weak solar-blind UV signals.Experimental results demonstrate that under zero bias conditions,with a UV light power density of 3.45μW/cm^(2) at 260 nm,the sample achieves a peak responsivity(R)of 0.085 A·W^(−1),an external quantum efficiency(EQE)of 40.7%,and a detectivity(D^(*))of 7.46×10^(12) cm·Hz^(1/2)·W^(−1).The system exhibits a bandpass characteristic within the 240–280 nm wavelength range,coupled with a high signal-to-noise ratio(SNR)of 39.74 dB.
基金supported by the National Natural Science Foundation of China(Nos.52102088 and 22075026)support from Teli Fellowship,Beijing Institute of Technology,and facility support from Analysis&Testing Center,and Experimental Center of Materials Sciences&Engineering at Beijing Institute of Technology.
文摘MnCO_(3)represents a potentially high-capacity and low-cost anode candidate to replace graphite for enhancing energy density of commercial lithium-ion batteries,but it suffers from poor electrical conductivity and serious volumetric change,largely hindering its practical applications.
文摘ZFJ Textile Machinery Co.,Ltd.,established in 1949,is a key enterprise directly managed by China Hi-Tech Group Corporation and falls under the jurisdiction of China National Machinery Industry Corporation Limited(Sinomach).As a leading enterprise in the textile machinery manufacturing industry,ZFJ is dedicated to providing global customers with complete equipment solutions covering the entire industry chain.During this exhibition,ZFJ primarily highlights three key features:"high-performance fibers,green fibers,and intelligent equipment,"with a focus on showcasing nine types of products,spanning various textile equipment categories,including chemical fiber,specialty fiber,nonwoven,sizing,and dyeing machinery.
基金supported by Fujian Science and Technology Planning Projects of China(Nos.2022T3067 and 2023H0045)the Self-deployment Project Research Programs of Haixi Institutes,Chinese Academy of Sciences(No.CXZX-2022-JQ12)the Self-deployment project of XIREM(No.2023GG02).
文摘Lithium/fluorinated carbon(Li/CF_(x))batteries are greatly limited in their applications mostly due to poor rate performances.In this study,N,P co-doped biomass carbon was synthesized using melamine and phytic acid as doping sources,and the resulting product was then utilized as a precursor for CF_(x).The resulting fluorinated biomass carbon has a high degree of fluorination,exceeding the specific capacity of commercial fluorinated graphite while also demonstrating exceptional performance at high discharge rates.During the fluorination process,N,P-containing functional groups were removed from the crystalline lattice in the basal plane.This facilitates the formation of a defect-rich carbon matrix,enhancing the F/C ratio by improving the fluorinated active sites and obtaining more highly active semi-ionic bonds.Additionally,the abundant defects and porous structure promote Li^(+)diffusion.Density functional theory calculations indicated that doping modification effectively reduces the energy barrier for Li+migration,enhancing Li+transport efficiency.The prepared CF_(x)delivers material with a maximum specific capacity of 919 mAh·g^(-1),while maintaining a specific capacity of 702 mAh·g^(-1)at a high discharge current density of 20C(with a capacity retention rate of 76.4%).In this study,fluorinated N,P co-doped biomass carbon,exhibiting ultrahigh capacity and high-rate performance,was prepared for the first time,which can potentially advance the commercialization of CF_(x).
文摘A high-performance liquid chromatography(HPLC)method has been developed using a CAPCELL PAK ADME(150 mm×4.6 mm,5μm)as analytical column and a gradient elution with 15 min using acetonitrile and 0.1%(in volume fraction)phosphoric acid water(pH=2.2)as the mobile phase.Three active substances in cosmetics were quantitatively detected simultaneously at a detection wavelength of 265 nm.The linear ranges of β-nicotinamide mononucleotides,ergothioneine and nicotinamide are 10~200 mg/L,5~100 mg/L and 5~100 mg/L respectively and the detection limits of three components are 3.0 mg/L,1.5 mg/L and 1.5 mg/L respectively.The recovery rate is 97.1~104.9%,with RSD≤2.0%.The method was applied to quantitative analysis of five samples of cosmetics toner,lotion,cream,essence and gel and three samples of raw materials.The results showed that the results of β-nicotinamide mononucleotide and ergothioneine in five cosmetics were consistent with the product label,while nicotinamide was inconsistent with the label.The purity of the three raw material samples was 99.5%,99.7% and 100.8%respectively.This method offers high precision,accuracy and short analysis time,making it a reliable approach for studying three active ingredients in cosmetics and suitable for quality control of related functional ingredients.
基金financially supported by the National Natural Science Foundation of China(Nos.52075351,51604177)the National Key Research and Development Program of China(No.2019YFA0705701)+4 种基金the National Funded Postdoctoral Researcher Program(No.GZC20231762)the Major S&T Infrastructure Construction Project of Sichuan Province(No.2020-510000-73-01441847)the International S&T Innovation Cooperation Program of Sichuan Province(No.2020YFH0039)the Chengdu International S&T Cooperation Funded Project(Nos.2020-GH02-00006HZ,2022-GH02-00027-HZ)the“1000 Talents Plan”of Sichuan Province,and the Talent Introduction Program of Sichuan University(No.YJ201410)。
文摘Anode active materials involving transition metal oxides and sulfides are of great significance for high energy density lithium-ion batteries(LIBs),but the huge volume expansion and inferior electronic conductivity upon cycling critically constrain their further application.Herein,from a new perspective,a highly conductive and stable 3D flexible composite current collector is rationally designed by facilely electrodepositing metallic Ni thin layer onto the carbon cloth(CC/Ni),which endows the supported active materials with exceptional electronic conductivity and structural stability.In addition,the homogeneously distributed metallic Ni protrusions external CC can strongly bond with the active components,ensuring the structural integrity of electrodes upon cycling.More importantly,the 3D network structure with large specific surface area provides abundant space to alleviate the volume expansion and more active sites for electrochemical reactions.Therefore,taking Ni_(3)S_(2)nanosheet(Ni_(3)S_(2)NS)anode as an example,the prepared Ni_(3)S_(2)NS@CC/Ni electrode shows a high specific capacity of 2.32 mAh/cm^(2)at 1mA/cm^(2)and high capacity retention of 1.68 mAh/cm^(2)at a high rate of 8mA/cm^(2).This study provides a universal approach to obtain highly conductive and stable 3D flexible current collectors towards high performance metal-ion batteries beyond LIBs.
基金supported by the National Key Research and Development Program of China (Grant No. 2024YFB3211701)the National Natural Science Foundation of China (Grant Nos. T2222011, 62174026, and 12274234)+1 种基金the National Key Research and Development Program of China (Grant Nos. 2023YFB3611400 and 2019YFA0308000)the Fundamental Research Funds for the Central Universities (Grant No. 242023k30027)。
文摘The weak interlayer van der Waals(vdW) interactions in two-dimensional(2D) vdW materials enable sliding ferroelectricity as an effective strategy for modulating their intrinsic properties. In this work, we systematically investigate the influence of interlayer sliding on the electronic behavior of PtSe_(2) using density functional theory(DFT) calculations. Our results demonstrate that interlayer sliding induces a pronounced photocurrent spanning the short-wavelength infrared to visible spectral ranges. Remarkably, under an applied gate voltage, the sliding ferroelectric PtSe_(2) exhibits anomalously enhanced photovoltaic performance and an ultrahigh extinction ratio.Transmission spectral analysis reveals that this phenomenon originates from band structure modifications driven by energy-level transitions. Furthermore, the observed photocurrent enhancement via sliding ferroelectricity demonstrates universality across diverse platinum-based optoelectronic devices. This study introduces a novel paradigm for tailoring the intrinsic characteristics of 2D vdW semiconductors, expanding the design space for next-generation ferroelectric materials in advanced optoelectronic applications.
文摘With the most advanced and sophisticated technologies and equipment,NYBELT is one of the largest manufacturers of flat transmission belts in the world.Under the Certified Quality,Environment,Occupational Health&Safety,and Energy Standardized ISO Management System,NYBELT can produce all kinds of flat transmission belts,roller coverings and conveyor belts applicable to textile,printing&packaging,electronics and other industries.Due to the superior quality and the reasonable prices,we have become well known in providing high quality belting products and excellent service to customers all over the world.Our success in the past gives us the confidence to look into the future with great expectations.
基金supported by the National Science Fund for Distinguished Young Scholars(Grant No.T2225027)the National Key R&D Program of China(Grant No.2023YFA1608902).
文摘Maintaining stable high temperatures under pressure remains a challenge in high-pressure,high-temperature experiments using multi-anvil presses(MAPs).Temperature fluctuations exceeding 10℃ at high pressures are common and particularly problematic with LaCrO_(3) heaters,which can experience significant power fluctuations and even failure due to substantial resistance changes—an issue conventional thyristorcontrolled heating systems cannot effectively manage.To address this limitation,we have developed the Multi-Anvil Stable Temperature controller(MASTer),a high-performance heating system optimized for MAP experiments.MASTer enables precise,high-speed measurement of heating parameters and power output control,incorporating a gentle regulation strategy to enhance stability.It ensures consistent heating across various heater types,including LaCrO_(3),with power fluctuations limited to±0.1 W and temperature fluctuations to within±2℃ in most cases.The design,operating principles,user interface,functionality,and performance of the heating system are discussed in detail.
文摘[Objectives]To extract and purify perfluoroalkyl and polyfluoroalkyl substances(PFAS)from aquatic products and determine the optimal pretreatment conditions.[Methods]The QuEChERS method was employed for the extraction and purification of PFAS in aquatic products.The detection of PFAS was carried out using liquid chromatography-tandem mass spectrometry(LC-MS/MS)in ESI negative ion mode with multiple reaction monitoring(MRM),and quantification was performed using the external standard method.By optimizing instrument parameters such as ion source temperature,spray voltage,and collision energy,high selectivity and sensitivity of the detection were ensured.[Results]The established calibration curves for 28 PFAS compounds compounds,covering a range of 0.02 to 20 ng/mL,demonstrated excellent linearity.Spike recovery tests yielded limits of detection(LOD)between 0.02 and 0.5μg/kg for the 28 PFAS compounds compounds,with recovery rates ranging from 72.2%to 113.0%.[Conclusions]The method established in this study demonstrates excellent linearity,and is accurate,reliable,efficient,simple,and rapid.It possesses considerable practical applicability and can be used for the quality and risk assessment of 28 PFAS compounds compounds in aquatic products,indicating high practical utility.
基金supported by the National Natural Science Foundation of China(Nos.51938005,52090082,and 52378395)the National Key Research and Development Program of China(No.2023YFB2604402).
文摘This study aims to assess the comprehensive strengthening effect of a steel-ultra high performance concrete(UHPC)composite strengthening method.The axial force-moment interaction curve(N-M curve)was calculated in a novel way,using cross-sectional strains at ultimate states as well as real-time stress measurements for each material.The enclosed area of the N-M curve was defined as a comprehensive performance index for the system.We validate our approach with comparisons to numerical modeling and full-scale four-point bending experiments.Additionally,strengthening effects were compared for different sagging and hogging moments based on material stress responses,and the impact of various strengthening parameters was analyzed.We find that the N-M curve of the strengthened cross-section envelops that of the un-strengthened cross-section.Notably,improvements in flexural capacity are greater under sagging moments during the large eccentric failure stage,and greater under hogging moments during the small eccentric failure stage.This discrepancy is attributed to the strength utilization of strengthening materials.These findings provide a reference for understanding the strengthening effects and parameters of steel-UHPC composite.
基金financially supported by the Liaoning Province Science and Technology Plan Joint Program(2023JH2/101700037).
文摘Ceramic cores are key to forming a cooling structure within the hollow blade cavities.The use of stereolithography(SL)3D printing technology eliminates the need for moulds,facilitating the preparation of complex-shaped ceramic cores.In this study,silica-based ceramic cores incorporating nano-3YSZ(3mol.% yttria stabilised zirconia)and micron-sized Y_(2)O_(3) were prepared via SL 3D printing ceramic technology to promote the formation of cristobalite and ZrSiO_(4),thereby improving the high-temperature properties.The flexural strength at 25℃ and 1,500℃,deflection at 1,500℃,shrinkage rate,and porosity of the core samples sintered at different temperatures(1,170℃,1,185℃,1,200℃,1,215℃,and 1,230℃)were tested and investigated.The mechanism underlying the high temperature performance of the cores was elucidated through analysis of cross-sectional morphology,element distribution,and phase constitution of the samples.As the sintering temperature increases,the shrinkage and flexural strength at 25℃ of the core rise,while the open porosity and deflection at 1,500℃ decrease.When the sintering temperature reaches 1,200℃ or higher,the 1,500℃ flexural strength can be measured,which increases as the sintering temperature rises.The core exhibits excellent creep resistance when sintered at temperatures of 1,200℃ and above.Considering the comprehensive performance requirements for the core,the sintering temperature of 1,200℃ was selected.At the sintering temperature of 1,200℃,the core exhibits shrinkage rates of 3.76%(X),3.38%(Y),and 3.95%(Z),alongside a flexural strength of 9.01 MPa at 25℃ and 32.15 MPa at 1,500℃,and an open porosity of 26.39%.The deflection of the core at 1,500℃ is 0.15 mm,which helps to maintain the dimensional stability of the ceramic core during casting.XRD results indicate that samples fractured after 25℃ flexural strength test still contain amorphous quartz glass,alongside substantial quantities of yttria stabilized zirconia and Y_(2)O_(3).Samples fractured after 1,500℃ flexural strength test exhibit significant crystallisation of amorphous quartz glass into cristobalite,with silica and 3YSZ combining to form ZrSiO_(4).Y_(2)O_(3) as a network modifier of the glass network destroys the bridging oxygen in the silica-oxygen bond,thereby reducing the energy required for glass crystallisation and promoting the crystallisation reaction of quartz glass to form cristobalite.In addition,nano-3YSZ combines with SiO_(2) at high temperatures to form ZrSiO_(4).Since cristobalite and ZrSiO_(4) are crystals,both of them have strong creep resistance,thus improving the high temperature flexural strength and deformation resistance of the ceramic cores.
基金Supported by the National Basic Research Programe of China("973"Program)(2009CB623203)the Construction Department of Zhejiang Province Foundation(1006)+1 种基金the Education Department of Zhejiang Province Foundation(Y200909029)the Doctoral Innovation Foundation of Nanjing University of Aeronautics andAstronautics(BCXJ07-04)~~
文摘Influences of admixtures on the workability and strength of high performance concrete （HPC） are in- vestigated. The types of investigated admixtures include naphthalene series high range water reducing agent, polycarboxlic series high range water reduce agent and sodium sulfate hardening accelerating agent. Two kinds of curing condition, namely steam curing condition and standard curing condition, are adopted. The result shows that HPC, added with polycarboxlic series of high performance water reducer, has high workability and strength, while sodium sulfate accelerating agent causes poor workability and low strength. Thus for vapor-cured HPC and its formulations, naphthalene series high range water reducing agent with less sodium sulfate should be given pri- ority. Therefore, the differences of curing conditions should be considered when selecting HPC admixtures.
基金National Natural Science Foundation(Grant No.813 73372)the Open Foundation of State Key Laboratory of Natural and Biomimetic Drugs(Grant No.SKL2012004)Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20110001110021 and 20130001110059)
文摘Abstract： In the presem study, we simultaneously quantified the levels of monoamine neurotransmitters （MANTs） and their metabolites （levodopa, norepinephrine, epinephrine, dopamine, 5-HT, 3,4-dihydroxyphenylacetic acid, homovanillic acid and 5-hydroxyindole-3-acetic acid） in different brain subregions of rats using a newly developed simple, sensitive and selective high-performance liquid chromatography with fluorescence detection （HPLC-FLD） method. In this new HPLC-FLD method, analytes were directly extracted and separated without deriveatization step within 20 min. The FLD wavelength was set at 280 nm and 330 nm for excitation and emission, respectively. The analytes were separated on an Agilent Eclipse Plus Cls column （4.6 mm×150 mm, 5.0 μm） equipped with an Agilent XDB-C18 security guard column （4.6 mm×12.5 mm, 5.0 lam）, and the column temperature was maintained at 35 ℃. The mobile phase for elution was isocratic. The mobile phase consisted of citric acid buffer （50 mmol/L citric acid, 50 mmol/L sodium acetate, 0.5 mmol/L octane sulfonic acid sodium salt, 0.5 mmol/L Na2EDTA and 5 mmol/L triethylamine, pH 3.8） and methanol （90：10, v/v） at a flow rate of 1.0 mL/min. The detection limit （DL） was 0.9-23 nM for all the MANTs and their metabolites with a sample volume of 50 μL. The method was shown to be highly reproducible in terms of peak area （intraday, 0.08%-1.85% RSD, n = 5）. The simultaneous measurement of these MANTs and their metabolites improved our understanding of the neurochemistry in the central nervous system （CNS） in relation to different addictive drugs （methamphetamine, heroin and their mixture） in drug-addicted rat models.
基金Administration Bureau of Traditional Chinese Medicine(2007-2008)for Scientific Research Program of TCM (Grant No.HL07057)
文摘Due to their biological and physiological importance,flavonoids receive considerable attention in the literature. Nowadays,high performance liquid chromatography（HPLC）is the most widely used analytical method.In this review,we summarize the principle of the choice of HPLC column and mobile phase,discuss and compare the features of various detections such as UV,fluorescence detection,electrochemical detection,chemilummescence detection,UV-MS etc.Recent developments in HPLC including ultra-LC and miniaturization of LC（micro-LC,capillary-LC,and nano-LC）,are also discussed.
