All-inorganic CsPbIBr_(2) perovskite has attracted widespread attention in photovoltaic and other optoelectronic devices because of its superior thermal stability.However,the deposition of high-quality solutionprocess...All-inorganic CsPbIBr_(2) perovskite has attracted widespread attention in photovoltaic and other optoelectronic devices because of its superior thermal stability.However,the deposition of high-quality solutionprocessed CsPbIBr_(2) perovskite films with large thicknesses remains challenging.Here,we develop a triple-component precursor(TCP) by employing lead bromide,lead iodide,and cesium bromide,to replace the most commonly used double-component precursor(DCP) consisting of lead bromide and cesium iodide.Remarkably,the TCP system significantly increases the solution concentration to 1.3 M,leading to a larger film thickness(~390 nm) and enhanced light absorption.The resultant CsPbIBr_(2) films were evaluated in planar n-i-p structured solar cells,which exhibit a considerably higher optimal photocurrent density of 11.50 mA cm^(-2) in comparison to that of DCP-based devices(10.69 mA cm^(-2)).By adopting an organic surface passivator,the maximum device efficiency using TCP is further boosted to a record efficiency of 12.8% for CsPbIBr_(2) perovskite solar cells.展开更多
The high compacted density LiNi<sub>0.5-x</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub>Mg<sub>x</sub>O<sub>2</sub> cathode material for lithium-ion batteries was syn...The high compacted density LiNi<sub>0.5-x</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub>Mg<sub>x</sub>O<sub>2</sub> cathode material for lithium-ion batteries was synthesized by high temperature solid-state method, taking the Mg element as a doping element and the spherical Ni<sub>0.5</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub> (OH)<sub>2</sub>, Li<sub>2</sub>CO<sub>3</sub> as raw materials. The effects of calcination temperature on the structure and properties of the products were investigated. The structure and morphology of cathode materials powder were analyzed by X-ray diffraction spectroscopy (XRD) and scanning electronmicroscopy (SEM). The electrochemical properties of the cathode materials were studied by charge-discharge test and cyclic properties test. The results show that LiNi<sub>0.4985</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub> Mg<sub>0.0015</sub>O<sub>2</sub> cathode material prepared at calcination temperature 930°C has a good layered structure, and the compacted density of the electrode sheet is above 3.68 g/cm<sup>3</sup>. The discharge capacity retention rate is more than 97.5% after 100 cycles at a charge-discharge rate of 1C, displaying a good cyclic performance.展开更多
In this study, an optimized high performance liquid chromatography-fluorescence detector (HPLC-FL) method for the determination of benzo[a]pyrene in edible oil was established. HPLC was performed with Thermo Fisher Sc...In this study, an optimized high performance liquid chromatography-fluorescence detector (HPLC-FL) method for the determination of benzo[a]pyrene in edible oil was established. HPLC was performed with Thermo Fisher Scientific C18 column (250 mm×4.6 mm, 5 μm) as the chromatographic column and acetonitrile and water as the mobile phase, and the excitation wavelength and emission wavelength of fluorescence detector were 286 and 430 nm, respectively. The response was high, and the linear range was 0.5-10.0 ng/ml. The lowest limit of detection was 0.11 ng/ml, and the average recovery was 92.5%. This method is suitable for quantitative analysis of benzo[a]pyrene content in edible oil.展开更多
Lithium sulfur batteries(LSBs)are recognized as promising devices for developing next-generation energy storage systems.In addition,they are attractive rechargeable battery systems for replacing lithium-ion batteries(...Lithium sulfur batteries(LSBs)are recognized as promising devices for developing next-generation energy storage systems.In addition,they are attractive rechargeable battery systems for replacing lithium-ion batteries(LIBs)for commercial use owing to their higher theoretical energy density and lower cost compared to those of LIBs.However,LSBs are still beset with some persistent issues that prevent them from being used industrially,such as the unavoidable dissolution of lithium polysulfide intermediates during electrochemical reactions and large volume expansion(up to 80%)upon the formation of Li_(2)S,resulting in serious battery life and safety limitations.In the process of solving these problems,it is necessary to maintain a high sulfur content in the cathode materials to ensure that the LSBs have high energy densities and excellent cycle performance.In this review,the novel preparation methods and cathode materials used for preparing LSBs in recent years are reviewed considering the sulfur content and cycle performance.In addition,the problems and difficulties in practically applying cathode materials are described,and the development trend is discussed.展开更多
The model performance in simulating soil water content(SWC) is crucial for successfully modeling earth’s system,especially in high mountainous areas.In this study,the performance of Community Land Model 5.0(CLM5.0) i...The model performance in simulating soil water content(SWC) is crucial for successfully modeling earth’s system,especially in high mountainous areas.In this study,the performance of Community Land Model 5.0(CLM5.0) in simulating liquid SWC was evaluated against observations from nine in-situ sites in the upper reach of the Heihe River Watershed(HRW),Northwest China.The CLM5.0 shows reliable performance in the study area with correlation coefficients(R) ranging between 0.79–0.93,root mean standard errors(RMSE)ranging between 0.044–0.097 m^(3)/m^(3),and the mean bias(BIAS) ranging between-0.084–0.061 m^(3)/m^(3).The slightly worse performance of CLM5.0 than CLM4.5 on alpine meadow and grassland is mainly caused by the revised canopy interception parameterization.The CLM5.0 overestimates interception and underestimates evapotranspiration(ET) on both alpine meadow and grassland during the growth period.The systematical overestimations at all the grassland sites indicate that the underestimation of ET is much larger than the overestimation of interception on grassland during growth period,while the errors of simulated interception and ET are partially canceled out on alpine meadow.Moreover,the underestimation of ET is more responsible for the overestimation of SWC than the overestimation of interception in the high mountainous area.It is necessary to estimate reasonable empirical parameter α(proportion of leaf water collection area) in interception parameterization scheme and further improve the dry surface layerbased soil evaporation resistance parameterization introduced in CLM5.0 in future researches.The performance of CLM5.0 is better under completely frozen stage than thawing stage and freezing stage,because of low variations of liquid SWC caused by extremely low hydraulic conductivity of soils.The underestimation of liquid SWC under frozen state is caused by underestimation of soil temperature,which leads to more ice mass and less liquid water in total water content.展开更多
Development of lead-free halide perovskites that are innocuous and stable has become an attractive trend in resistive random access memory(RRAM)fields.However,their inferior memory properties compared with the lead-ba...Development of lead-free halide perovskites that are innocuous and stable has become an attractive trend in resistive random access memory(RRAM)fields.However,their inferior memory properties compared with the lead-based analogs hinder their commercialization.Herein,the lead-free Cs_(3)Bi_(2)Br_(9)perovskite quantum dot(PQD)-based RRAMs are reported with outstanding memory performance,where Cs_(3)Bi_(2)Br_(9)quantum dots(QDs)are synthesized via a modified ligand-assisted recrystallization process.This is the first report of applying Cs_(3)Bi_(2)Br_(9)QDs as the switching layer for RRAM device.The Cs_(3)Bi_(2)Br_(9)QD device demonstrates nonvolatile resistive switching(RS)effect with large ON/OFF ratio of 105,low set voltage of-0.45 V,as well as good reliability,reproducibility,and flexibility.Concurrently,the device exhibits the notable tolerance toward moisture,heat and light illumination,and long-term stability of 200 days.More impressively,the device shows the reliable light-modulated RS behavior,and therefrom the logic gate operations including"AND"and"OR"are implemented,foreboding its prospect in logic circuits integrated with storage and computation.Such multifunctionality of device could be derived from the unique 2D layered crystal structure,small particle size,quantum confinement effect,and photoresponse of Cs_(3)Bi_(2)Br_(9)QDs.This work provides the strategy toward the high-performance RRAMs based on stable and eco-friendly perovskites for future applications.展开更多
The purpose of this study was to establish a high-performance liquid chromatography (HPLC) method for the simultaneous determination of sodium danshensu, protocatechuic aldehyde, rosmarinic acid, salvianolic acid B, a...The purpose of this study was to establish a high-performance liquid chromatography (HPLC) method for the simultaneous determination of sodium danshensu, protocatechuic aldehyde, rosmarinic acid, salvianolic acid B, and 4-coumaric acid in Danhong injection. The chromatographic method employed was as follows: the column was a Welch Ultimate XB-C18 column (250 mm × 4.6 mm, 10 μm), the mobile phase was a gradient elution of 0.4% formic acid aqueous solution (A) and acetonitrile (B), the detection wavelengths were 280 nm for sodium danshensu, protocatechuic aldehyde, and salvianolic acid B and 326 nm for 4-coumaric acid and rosmarinic acid, the sample volume was 10 μL, the flow rate was 1.0 mL/min, and the column temperature was 35°C. This method can realize the separation and determination of sodium danshensu, protocatechuic aldehyde, rosmarinic acid, salvianolic acid B, and 4-coumaric acid within 50 minutes. The linear relationships of the five peak areas and their concentrations are good (R2> 0.9997). The precision RSD values are all less than 1.0%. The reproducibility RSD values are all less than 1.3%. The stability RSD values are all less than 2.2%. The recovery values ranged from 92.4% to 99.4%. This method is simple, accurate, and reproducible. It can be used for the determination of sodium danshensu, protocatechuic aldehyde, rosmarinic acid, salvianolic acid B, and 4-coumaric acid in Danhong injection.展开更多
[Objectives]A high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)method was established for the determination of 14β-receptor agonist residues in mutton.[Methods]Samples were hydrolyzed byβ-g...[Objectives]A high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)method was established for the determination of 14β-receptor agonist residues in mutton.[Methods]Samples were hydrolyzed byβ-glucuronidase and extracted with 5%acetic acid-acetonitrile(1:99,V/V)solution.An Eclipse plus C 18 column was used for separation,and the MRM mode was used for qualitative analysis,and the external standard method was used for quantitative analysis of matrix standard solutions.[Results]Under the optimal conditions,the retention time of the 14 kinds ofβ-receptor agonists ranged from 1.0 to 9.5 min.When the mass concentration was in the range of 0.05-0.50μg/ml,the linear relationship ofβ-receptor agonists was good,with correlation coefficients(r)≥0.9992.The detection limits of the method were in the range of 0.04-0.87μg/kg,and the quantitative limits were in the range of 0.35-1.86μg/kg.The average recovery values were in the range of 82.8%-108.9%,with RSDs(n=6)in the range of 1.9%-6.7%.[Conclusions]The method is simple,sensitive,reproducible,accurate,and can be used for simultaneous determination of the 14 kinds ofβ-receptor agonist residues in mutton.展开更多
There is currently great optimism within the electronics community that gallium oxide(Ga_(2)O_(3)) ultra-wide bandgap semiconductors have unprecedented prospects for eventually revolutionizing a rich variety of power ...There is currently great optimism within the electronics community that gallium oxide(Ga_(2)O_(3)) ultra-wide bandgap semiconductors have unprecedented prospects for eventually revolutionizing a rich variety of power electronic applications. Specially, benefiting from its ultra-high bandgap of around 4.8 eV, it is expected that the emerging Ga_(2)O_(3) technology would offer an exciting platform to deliver massively enhanced device performance for power electronics and even completely new applications.展开更多
Further improving the railway innovation capacity and technological strength is the important goal of the 14th Five-Year Plan for railway scientific and technological innovation.It includes promoting the deep integrat...Further improving the railway innovation capacity and technological strength is the important goal of the 14th Five-Year Plan for railway scientific and technological innovation.It includes promoting the deep integration of cutting-edge technologies with the railway systems,strengthening the research and application of intelligent railway technologies,applying green computing technologies and advancing the collaborative sharing of transportation big data.The high-speed rail system tasks need to process huge amounts of data and heavy workload with the requirement of ultra-fast response.Therefore,it is of great necessity to promote computation efficiency by applying High Performance Computing(HPC)to high-speed rail systems.The HPC technique is a great solution for improving the performance,efficiency,and safety of high-speed rail systems.In this review,we introduce and analyze the application research of high performance computing technology in the field of highspeed railways.These HPC applications are cataloged into four broad categories,namely:fault diagnosis,network and communication,management system,and simulations.Moreover,challenges and issues to be addressed are discussed and further directions are suggested.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
Financing of the African Integrated High-Speed Railway Network (AIHSRN) through Standard Gauge Railway (SGR) Projects is very expensive. As a result, most of the African countries seek financial supports from the Inte...Financing of the African Integrated High-Speed Railway Network (AIHSRN) through Standard Gauge Railway (SGR) Projects is very expensive. As a result, most of the African countries seek financial supports from the International Financial Institutions (IFIs). However, conditions provided by the IFIs through the Performance Standards (PS) of the International Financial Corporation (IFC) increase cost of the projects and thus, it becomes a burden to most of the African countries. This study aimed to explore the causes of IFC-PS through the SGR Projects that escalate costs and how to address them. The Tanzania SGR Lot 1 Project that covered 205 km from Dar es Salaam to Morogoro was selected as a case study. The methods used for data collection involved literature review, focus group discussions and interviews. The results and findings show a gap between the IFC-PS and the National Laws and Regulations that escalates costs of the projects if funds from the IFIs were to be secured. To bridge the gap, it is recommended that the African countries should engage into negotiations with the IFIs to agree to waive IFC-PS conditions that escalate costs provided they are adequately covered in the national laws and regulations;engagement of locally established national and regional financial institutions;and the responsible government institutions in the African countries should sit together for assessment and review of the IFC-PS against the national laws and regulations.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
The ginkgo terpenoids including bilobalide and ginkgolides are the main pharmaceutical components in the leaves or extracts of Ginkgo biloba L. In this paper, the analysis of bilobalide and ginkgolides in leaves of Gi...The ginkgo terpenoids including bilobalide and ginkgolides are the main pharmaceutical components in the leaves or extracts of Ginkgo biloba L. In this paper, the analysis of bilobalide and ginkgolides in leaves of Ginkgo biloba L. by high performance liquid chromatography (HPLC)-electrospray ionization (ESI)-mass spectrometry (MS) was carried out. The separation was performed on Inertsil ODS3 column with methanol-water (36:64) as mobile phase, with 1 mL·min -1 of flow rate at 35℃. Then the mass spectrum analysis was conducted by ZMD micromass electrospray ionization (ESI)-mass spectrometer (MS). The HPLC total ion chromatogram and selected ion chromatogram (with 325, 407, 423, 439 of m/z) of the sample and ESI-/MS mass spectra of the peaks in the chromatograms were obtained. So bilobalide, ginkgolide A, B, C and J in Ginkgo biloba L. leaves were identified. The method is easy and rapid, with a good accuracy.展开更多
An improved high fan-in domino circuit is proposed. The nMOS pull-down network of the circuit is divided into several blocks to reduce the capacitance of the dynamic node and each block only needs a small keeper trans...An improved high fan-in domino circuit is proposed. The nMOS pull-down network of the circuit is divided into several blocks to reduce the capacitance of the dynamic node and each block only needs a small keeper transistor to maintain the noise margin. Because we omit the footer transistor, the circuit has better performance than the standard domino circuit. A 64-input OR-gate implemented with the structure is simulated using HSPICE under typical conditions of 0.13μm CMOS technology. The average delay of the circuit is 63.9ps, the average power dissipation is 32.4μW, and the area is l15μm^2. Compared to compound domino logic, the proposed circuit can reduce delay and power dissipation by 55% and 38%, respectively.展开更多
A high performance 70nm CMOS device has been demonstrated for the first time in the continent, China. Some innovations in techniques are applied to restrain the short channel effect and improve the driving ability, ...A high performance 70nm CMOS device has been demonstrated for the first time in the continent, China. Some innovations in techniques are applied to restrain the short channel effect and improve the driving ability, such as 3nm nitrided oxide, dual poly Si gate electrode, novel super steep retrograde channel doping by heavy ion implantation, ultra shallow S/D extension formed by Ge PAI(Pre Amorphism Implantation) plus LEI(Low Energy Implantation), thin and low resistance Ti SALICIDE by Ge PAI and special cleaning, etc. The shortest channel length of the CMOS device is 70nm. The threshold voltages, G m and off current are 0 28V,490mS·mm -1 and 0 08nA/μm for NMOS and -0 3V,340mS·mm -1 and 0 2nA/μm for PMOS, respectively. Delays of 23 5ps/stage at 1 5V, 17 5ps/stage at 2 0V and 12 5ps/stage at 3V are achieved in the 57 stage unloaded 100nm CMOS ring oscillator circuits.展开更多
The high-speed on/off valve(HSV)serves as the fundamental component responsible for generating discrete fluids within digital hydraulic systems.As the switching frequency of the HSV increases,the properties of the gen...The high-speed on/off valve(HSV)serves as the fundamental component responsible for generating discrete fluids within digital hydraulic systems.As the switching frequency of the HSV increases,the properties of the generated discrete fluid approach those of continuous fluids.Therefore,a higher frequency response characteristic of HSV is the key to ensure the control accuracy of digital hydraulic systems.However,the current research mainly focuses on its dynamic performance,but neglect its FRC.This paper presents a theoretical analysis demonstrating that the FRC of the HSV can be enhanced by minimizing its switching time.The maximum switching frequency(MSF)is mainly determined by opening dynamic performance when HSV operates with low switching duty ratio(SDR),whereas the closing dynamic performance limits the MSF when HSV operates with high SDR.Building upon these findings,the pre-excitation control algorithm(PECA)is proposed to reduce the switching time of the HSV,and consequently enhance its FRC.Experimental results demonstrate that PECA shortens the opening delay time of HSV by 1.12 ms,the closing delay time by 2.54 ms,and the closing moving time by 0.47 ms in comparison to the existing advanced control algorithms.As a result,a larger MSF of 417 Hz and a wider controllable SDR range from 20%to 70%were achieved at a switching frequency of 250 Hz.Thus,the proposed PFCA in this paper has been verified as an effective and promising approach for enhancing the control performance of digital hydraulic systems.展开更多
To develop a sensitive high performance liquid chromatography (HPLC) assay for the determination of trans-resveratrol in mouse liver. The whole liver of a mouse was removed from the body, homogenated, and extracted ...To develop a sensitive high performance liquid chromatography (HPLC) assay for the determination of trans-resveratrol in mouse liver. The whole liver of a mouse was removed from the body, homogenated, and extracted by ethyl acetate. The organic layer was isolated and evaporated to dryness, the residue was reconstituted in 0.2 mL mobile phase for centrifugation, and 50 uL of the supernatant was injected into the/-IPLC instrument. The sample was separated on a Shimadzu ODS column (150 mm × 4.6 mm, 5 um) at 35 ℃ and detected by ultraviolet (UV) detector at the wavelength of 305 nm. The mobile phase consisted of methanol and 0.1 mol/L acetic acid (4:6, v/v) with the flow-rote at 1 mL/min. The limit of detection was 3.0 ng/g in liver homogenate with a signal/noise ratio of 3:1. The linear range of the calibration curve was 5.0-120.0 ng/g. The mean recoveries at the concentrations of 6, 10 and 80 ng/g were 102%, 96.0% and 91.5%, respectively. The RSDs for inter- and intra-day assays were less than 5%. Compared with other reported methods, this method was faster and more sensitive. It was also proved to be of good linearity, selectivity, accuracy and precision, and can be efficiently applied to the pharmacoldnetic study of trans-resveratrol in mouse liver.展开更多
The influence of glycol,the main composition of the most frequently used aircraft dicer,on the freeze-thaw durability of high performance concrete(HPC)is investigated.Freeze-thaw durability of HPC is tested by accel...The influence of glycol,the main composition of the most frequently used aircraft dicer,on the freeze-thaw durability of high performance concrete(HPC)is investigated.Freeze-thaw durability of HPC is tested by accelerated freeze-thaw test.Four kinds of the solution,i.e.,tap water,3.5% NaCl solution,glycol solutions,and a LBR-A type commercial aircraft deicer are employed.Results show that freeze-thaw durability of HPC exposed to glycol solutions is closely related to the solution concentrations.The failure of HPC exposed to 3.5% glycol solution is similar to that of those exposed to 3.5% NaCl solution,i.e.,serious surface scaling.While the damage of HPC exposed to 12.5%—25% glycol solutions is postponed.Compared with glycol solution,the commercial aircraft deicer has much more negative effects on HPC freeze-thaw durability compared with 3.5% NaCl solution.In the presence of commercial aircraft deicer for HPC subjected to freeze-thaw cycles,the deterioration is mainly due to scaling and spalling.展开更多
In order to improve the reliability of the spacecraft micro cold gas propulsion system and realize the precise control of the spacecraft attitude and orbit, a micro-thrust, high-precision cold gas thruster is carried ...In order to improve the reliability of the spacecraft micro cold gas propulsion system and realize the precise control of the spacecraft attitude and orbit, a micro-thrust, high-precision cold gas thruster is carried out, at the same time due to the design requirements of the spacecraft, this micro-thrust should be continuous working more than 60 minutes, the traditional solenoid valve used for the thrusts can’t complete the mission, so a long-life micro latching valve is developed as the control valve for this micro thruster, because the micro latching valve can keep its position when it cuts off the outage. Firstly, the authors introduced the design scheme and idea of the thruster. Secondly, the performance of the latching valve and the flow characteristics of the nozzle were simulated. Finally, from the experimental results and compared with the numerical study, it shows that the long-life micro cold gas thruster developed in this paper meets the mission requirements.展开更多
基金The authors acknowledge the financial support by the National Natural Science Foundation of China(52161145408 and 21975038)the Research and Innovation Team Project of Dalian University of Technology(DUT2022TB10)+2 种基金the Fundamental Research Funds for the Central Universities(DUT22QN213)the Innovation Technology Fund(MRP/040/21X)the Green Technology Fund(GTF202020164)for their financial support。
文摘All-inorganic CsPbIBr_(2) perovskite has attracted widespread attention in photovoltaic and other optoelectronic devices because of its superior thermal stability.However,the deposition of high-quality solutionprocessed CsPbIBr_(2) perovskite films with large thicknesses remains challenging.Here,we develop a triple-component precursor(TCP) by employing lead bromide,lead iodide,and cesium bromide,to replace the most commonly used double-component precursor(DCP) consisting of lead bromide and cesium iodide.Remarkably,the TCP system significantly increases the solution concentration to 1.3 M,leading to a larger film thickness(~390 nm) and enhanced light absorption.The resultant CsPbIBr_(2) films were evaluated in planar n-i-p structured solar cells,which exhibit a considerably higher optimal photocurrent density of 11.50 mA cm^(-2) in comparison to that of DCP-based devices(10.69 mA cm^(-2)).By adopting an organic surface passivator,the maximum device efficiency using TCP is further boosted to a record efficiency of 12.8% for CsPbIBr_(2) perovskite solar cells.
文摘The high compacted density LiNi<sub>0.5-x</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub>Mg<sub>x</sub>O<sub>2</sub> cathode material for lithium-ion batteries was synthesized by high temperature solid-state method, taking the Mg element as a doping element and the spherical Ni<sub>0.5</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub> (OH)<sub>2</sub>, Li<sub>2</sub>CO<sub>3</sub> as raw materials. The effects of calcination temperature on the structure and properties of the products were investigated. The structure and morphology of cathode materials powder were analyzed by X-ray diffraction spectroscopy (XRD) and scanning electronmicroscopy (SEM). The electrochemical properties of the cathode materials were studied by charge-discharge test and cyclic properties test. The results show that LiNi<sub>0.4985</sub>Co<sub>0.2</sub>Mn<sub>0.3</sub> Mg<sub>0.0015</sub>O<sub>2</sub> cathode material prepared at calcination temperature 930°C has a good layered structure, and the compacted density of the electrode sheet is above 3.68 g/cm<sup>3</sup>. The discharge capacity retention rate is more than 97.5% after 100 cycles at a charge-discharge rate of 1C, displaying a good cyclic performance.
文摘In this study, an optimized high performance liquid chromatography-fluorescence detector (HPLC-FL) method for the determination of benzo[a]pyrene in edible oil was established. HPLC was performed with Thermo Fisher Scientific C18 column (250 mm×4.6 mm, 5 μm) as the chromatographic column and acetonitrile and water as the mobile phase, and the excitation wavelength and emission wavelength of fluorescence detector were 286 and 430 nm, respectively. The response was high, and the linear range was 0.5-10.0 ng/ml. The lowest limit of detection was 0.11 ng/ml, and the average recovery was 92.5%. This method is suitable for quantitative analysis of benzo[a]pyrene content in edible oil.
基金the National Natural Science Foundation of China(52103093)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(2021QNRC001)+2 种基金the Jiangxi Provincial Natural Science Foundation(20212BAB214048)Science and Technology Support Project of Shangrao(2020L009,2021J006)Science and Technological Project of Education Department of Jiangxi(GJJ211704)for funding their contributions to this paper。
文摘Lithium sulfur batteries(LSBs)are recognized as promising devices for developing next-generation energy storage systems.In addition,they are attractive rechargeable battery systems for replacing lithium-ion batteries(LIBs)for commercial use owing to their higher theoretical energy density and lower cost compared to those of LIBs.However,LSBs are still beset with some persistent issues that prevent them from being used industrially,such as the unavoidable dissolution of lithium polysulfide intermediates during electrochemical reactions and large volume expansion(up to 80%)upon the formation of Li_(2)S,resulting in serious battery life and safety limitations.In the process of solving these problems,it is necessary to maintain a high sulfur content in the cathode materials to ensure that the LSBs have high energy densities and excellent cycle performance.In this review,the novel preparation methods and cathode materials used for preparing LSBs in recent years are reviewed considering the sulfur content and cycle performance.In addition,the problems and difficulties in practically applying cathode materials are described,and the development trend is discussed.
基金partially funded by the National Natural Science Foundation of China (41877148 and 42030501)Key Laboratory of Ecohydrology of Inland River Basin,Chinese Academy of Sciences。
文摘The model performance in simulating soil water content(SWC) is crucial for successfully modeling earth’s system,especially in high mountainous areas.In this study,the performance of Community Land Model 5.0(CLM5.0) in simulating liquid SWC was evaluated against observations from nine in-situ sites in the upper reach of the Heihe River Watershed(HRW),Northwest China.The CLM5.0 shows reliable performance in the study area with correlation coefficients(R) ranging between 0.79–0.93,root mean standard errors(RMSE)ranging between 0.044–0.097 m^(3)/m^(3),and the mean bias(BIAS) ranging between-0.084–0.061 m^(3)/m^(3).The slightly worse performance of CLM5.0 than CLM4.5 on alpine meadow and grassland is mainly caused by the revised canopy interception parameterization.The CLM5.0 overestimates interception and underestimates evapotranspiration(ET) on both alpine meadow and grassland during the growth period.The systematical overestimations at all the grassland sites indicate that the underestimation of ET is much larger than the overestimation of interception on grassland during growth period,while the errors of simulated interception and ET are partially canceled out on alpine meadow.Moreover,the underestimation of ET is more responsible for the overestimation of SWC than the overestimation of interception in the high mountainous area.It is necessary to estimate reasonable empirical parameter α(proportion of leaf water collection area) in interception parameterization scheme and further improve the dry surface layerbased soil evaporation resistance parameterization introduced in CLM5.0 in future researches.The performance of CLM5.0 is better under completely frozen stage than thawing stage and freezing stage,because of low variations of liquid SWC caused by extremely low hydraulic conductivity of soils.The underestimation of liquid SWC under frozen state is caused by underestimation of soil temperature,which leads to more ice mass and less liquid water in total water content.
基金supported by the National Natural Science Foundation of China(21374106)National Natural Science Foundation of China(11774318,12074347,and U1304212)National Key Research Program of China(2016YFA0200104).
文摘Development of lead-free halide perovskites that are innocuous and stable has become an attractive trend in resistive random access memory(RRAM)fields.However,their inferior memory properties compared with the lead-based analogs hinder their commercialization.Herein,the lead-free Cs_(3)Bi_(2)Br_(9)perovskite quantum dot(PQD)-based RRAMs are reported with outstanding memory performance,where Cs_(3)Bi_(2)Br_(9)quantum dots(QDs)are synthesized via a modified ligand-assisted recrystallization process.This is the first report of applying Cs_(3)Bi_(2)Br_(9)QDs as the switching layer for RRAM device.The Cs_(3)Bi_(2)Br_(9)QD device demonstrates nonvolatile resistive switching(RS)effect with large ON/OFF ratio of 105,low set voltage of-0.45 V,as well as good reliability,reproducibility,and flexibility.Concurrently,the device exhibits the notable tolerance toward moisture,heat and light illumination,and long-term stability of 200 days.More impressively,the device shows the reliable light-modulated RS behavior,and therefrom the logic gate operations including"AND"and"OR"are implemented,foreboding its prospect in logic circuits integrated with storage and computation.Such multifunctionality of device could be derived from the unique 2D layered crystal structure,small particle size,quantum confinement effect,and photoresponse of Cs_(3)Bi_(2)Br_(9)QDs.This work provides the strategy toward the high-performance RRAMs based on stable and eco-friendly perovskites for future applications.
文摘The purpose of this study was to establish a high-performance liquid chromatography (HPLC) method for the simultaneous determination of sodium danshensu, protocatechuic aldehyde, rosmarinic acid, salvianolic acid B, and 4-coumaric acid in Danhong injection. The chromatographic method employed was as follows: the column was a Welch Ultimate XB-C18 column (250 mm × 4.6 mm, 10 μm), the mobile phase was a gradient elution of 0.4% formic acid aqueous solution (A) and acetonitrile (B), the detection wavelengths were 280 nm for sodium danshensu, protocatechuic aldehyde, and salvianolic acid B and 326 nm for 4-coumaric acid and rosmarinic acid, the sample volume was 10 μL, the flow rate was 1.0 mL/min, and the column temperature was 35°C. This method can realize the separation and determination of sodium danshensu, protocatechuic aldehyde, rosmarinic acid, salvianolic acid B, and 4-coumaric acid within 50 minutes. The linear relationships of the five peak areas and their concentrations are good (R2> 0.9997). The precision RSD values are all less than 1.0%. The reproducibility RSD values are all less than 1.3%. The stability RSD values are all less than 2.2%. The recovery values ranged from 92.4% to 99.4%. This method is simple, accurate, and reproducible. It can be used for the determination of sodium danshensu, protocatechuic aldehyde, rosmarinic acid, salvianolic acid B, and 4-coumaric acid in Danhong injection.
基金Supported by The Fourth Batch of High-end Talent Project in Hebei ProvinceTangshan Science and Technology Entrepreneurship and Innovation Leading Talent Project(21130243A).
文摘[Objectives]A high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)method was established for the determination of 14β-receptor agonist residues in mutton.[Methods]Samples were hydrolyzed byβ-glucuronidase and extracted with 5%acetic acid-acetonitrile(1:99,V/V)solution.An Eclipse plus C 18 column was used for separation,and the MRM mode was used for qualitative analysis,and the external standard method was used for quantitative analysis of matrix standard solutions.[Results]Under the optimal conditions,the retention time of the 14 kinds ofβ-receptor agonists ranged from 1.0 to 9.5 min.When the mass concentration was in the range of 0.05-0.50μg/ml,the linear relationship ofβ-receptor agonists was good,with correlation coefficients(r)≥0.9992.The detection limits of the method were in the range of 0.04-0.87μg/kg,and the quantitative limits were in the range of 0.35-1.86μg/kg.The average recovery values were in the range of 82.8%-108.9%,with RSDs(n=6)in the range of 1.9%-6.7%.[Conclusions]The method is simple,sensitive,reproducible,accurate,and can be used for simultaneous determination of the 14 kinds ofβ-receptor agonist residues in mutton.
文摘There is currently great optimism within the electronics community that gallium oxide(Ga_(2)O_(3)) ultra-wide bandgap semiconductors have unprecedented prospects for eventually revolutionizing a rich variety of power electronic applications. Specially, benefiting from its ultra-high bandgap of around 4.8 eV, it is expected that the emerging Ga_(2)O_(3) technology would offer an exciting platform to deliver massively enhanced device performance for power electronics and even completely new applications.
基金supported in part by the Talent Fund of Beijing Jiaotong University(2023XKRC017)in part by Research and Development Project of China State Railway Group Co.,Ltd.(P2022Z003).
文摘Further improving the railway innovation capacity and technological strength is the important goal of the 14th Five-Year Plan for railway scientific and technological innovation.It includes promoting the deep integration of cutting-edge technologies with the railway systems,strengthening the research and application of intelligent railway technologies,applying green computing technologies and advancing the collaborative sharing of transportation big data.The high-speed rail system tasks need to process huge amounts of data and heavy workload with the requirement of ultra-fast response.Therefore,it is of great necessity to promote computation efficiency by applying High Performance Computing(HPC)to high-speed rail systems.The HPC technique is a great solution for improving the performance,efficiency,and safety of high-speed rail systems.In this review,we introduce and analyze the application research of high performance computing technology in the field of highspeed railways.These HPC applications are cataloged into four broad categories,namely:fault diagnosis,network and communication,management system,and simulations.Moreover,challenges and issues to be addressed are discussed and further directions are suggested.
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.
文摘Financing of the African Integrated High-Speed Railway Network (AIHSRN) through Standard Gauge Railway (SGR) Projects is very expensive. As a result, most of the African countries seek financial supports from the International Financial Institutions (IFIs). However, conditions provided by the IFIs through the Performance Standards (PS) of the International Financial Corporation (IFC) increase cost of the projects and thus, it becomes a burden to most of the African countries. This study aimed to explore the causes of IFC-PS through the SGR Projects that escalate costs and how to address them. The Tanzania SGR Lot 1 Project that covered 205 km from Dar es Salaam to Morogoro was selected as a case study. The methods used for data collection involved literature review, focus group discussions and interviews. The results and findings show a gap between the IFC-PS and the National Laws and Regulations that escalates costs of the projects if funds from the IFIs were to be secured. To bridge the gap, it is recommended that the African countries should engage into negotiations with the IFIs to agree to waive IFC-PS conditions that escalate costs provided they are adequately covered in the national laws and regulations;engagement of locally established national and regional financial institutions;and the responsible government institutions in the African countries should sit together for assessment and review of the IFC-PS against the national laws and regulations.
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.
文摘The ginkgo terpenoids including bilobalide and ginkgolides are the main pharmaceutical components in the leaves or extracts of Ginkgo biloba L. In this paper, the analysis of bilobalide and ginkgolides in leaves of Ginkgo biloba L. by high performance liquid chromatography (HPLC)-electrospray ionization (ESI)-mass spectrometry (MS) was carried out. The separation was performed on Inertsil ODS3 column with methanol-water (36:64) as mobile phase, with 1 mL·min -1 of flow rate at 35℃. Then the mass spectrum analysis was conducted by ZMD micromass electrospray ionization (ESI)-mass spectrometer (MS). The HPLC total ion chromatogram and selected ion chromatogram (with 325, 407, 423, 439 of m/z) of the sample and ESI-/MS mass spectra of the peaks in the chromatograms were obtained. So bilobalide, ginkgolide A, B, C and J in Ginkgo biloba L. leaves were identified. The method is easy and rapid, with a good accuracy.
基金the National High-Tech Research and Development Program of China(No.2005AA110020)~~
文摘An improved high fan-in domino circuit is proposed. The nMOS pull-down network of the circuit is divided into several blocks to reduce the capacitance of the dynamic node and each block only needs a small keeper transistor to maintain the noise margin. Because we omit the footer transistor, the circuit has better performance than the standard domino circuit. A 64-input OR-gate implemented with the structure is simulated using HSPICE under typical conditions of 0.13μm CMOS technology. The average delay of the circuit is 63.9ps, the average power dissipation is 32.4μW, and the area is l15μm^2. Compared to compound domino logic, the proposed circuit can reduce delay and power dissipation by 55% and 38%, respectively.
文摘A high performance 70nm CMOS device has been demonstrated for the first time in the continent, China. Some innovations in techniques are applied to restrain the short channel effect and improve the driving ability, such as 3nm nitrided oxide, dual poly Si gate electrode, novel super steep retrograde channel doping by heavy ion implantation, ultra shallow S/D extension formed by Ge PAI(Pre Amorphism Implantation) plus LEI(Low Energy Implantation), thin and low resistance Ti SALICIDE by Ge PAI and special cleaning, etc. The shortest channel length of the CMOS device is 70nm. The threshold voltages, G m and off current are 0 28V,490mS·mm -1 and 0 08nA/μm for NMOS and -0 3V,340mS·mm -1 and 0 2nA/μm for PMOS, respectively. Delays of 23 5ps/stage at 1 5V, 17 5ps/stage at 2 0V and 12 5ps/stage at 3V are achieved in the 57 stage unloaded 100nm CMOS ring oscillator circuits.
基金Supported by National Natural Science Foundation of China (Grant No.52005441)Young Elite Scientist Sponsorship Program by CAST of China (Grant No.2022-2024QNRC001)+4 种基金Zhejiang Provincial Natural Science Foundation of China (Grant No.LQ21E050017)Zhejiang Provincial“Pioneer”and“Leading Goose”R&D Program of China (Grant Nos.2022C01122,2022C01132)State Key Laboratory of Mechanical System and Vibration of China (Grant No.MSV202316)Fundamental Research Funds for the Provincial Universities of Zhejiang of China (Grant No.RF-A2023007)Research Project of ZJUT of China (Grant No.GYY-ZH-2023075)。
文摘The high-speed on/off valve(HSV)serves as the fundamental component responsible for generating discrete fluids within digital hydraulic systems.As the switching frequency of the HSV increases,the properties of the generated discrete fluid approach those of continuous fluids.Therefore,a higher frequency response characteristic of HSV is the key to ensure the control accuracy of digital hydraulic systems.However,the current research mainly focuses on its dynamic performance,but neglect its FRC.This paper presents a theoretical analysis demonstrating that the FRC of the HSV can be enhanced by minimizing its switching time.The maximum switching frequency(MSF)is mainly determined by opening dynamic performance when HSV operates with low switching duty ratio(SDR),whereas the closing dynamic performance limits the MSF when HSV operates with high SDR.Building upon these findings,the pre-excitation control algorithm(PECA)is proposed to reduce the switching time of the HSV,and consequently enhance its FRC.Experimental results demonstrate that PECA shortens the opening delay time of HSV by 1.12 ms,the closing delay time by 2.54 ms,and the closing moving time by 0.47 ms in comparison to the existing advanced control algorithms.As a result,a larger MSF of 417 Hz and a wider controllable SDR range from 20%to 70%were achieved at a switching frequency of 250 Hz.Thus,the proposed PFCA in this paper has been verified as an effective and promising approach for enhancing the control performance of digital hydraulic systems.
基金Postdoctoral Scientific Research Station of Gansu Yasheng Groups.
文摘To develop a sensitive high performance liquid chromatography (HPLC) assay for the determination of trans-resveratrol in mouse liver. The whole liver of a mouse was removed from the body, homogenated, and extracted by ethyl acetate. The organic layer was isolated and evaporated to dryness, the residue was reconstituted in 0.2 mL mobile phase for centrifugation, and 50 uL of the supernatant was injected into the/-IPLC instrument. The sample was separated on a Shimadzu ODS column (150 mm × 4.6 mm, 5 um) at 35 ℃ and detected by ultraviolet (UV) detector at the wavelength of 305 nm. The mobile phase consisted of methanol and 0.1 mol/L acetic acid (4:6, v/v) with the flow-rote at 1 mL/min. The limit of detection was 3.0 ng/g in liver homogenate with a signal/noise ratio of 3:1. The linear range of the calibration curve was 5.0-120.0 ng/g. The mean recoveries at the concentrations of 6, 10 and 80 ng/g were 102%, 96.0% and 91.5%, respectively. The RSDs for inter- and intra-day assays were less than 5%. Compared with other reported methods, this method was faster and more sensitive. It was also proved to be of good linearity, selectivity, accuracy and precision, and can be efficiently applied to the pharmacoldnetic study of trans-resveratrol in mouse liver.
基金Supported by the National Basic Research Program of China("973"Program)(2009CB623203)the China Postdoctoral Science Foundation(20070421036)+1 种基金the Natural Science Foundation of Jiangsu Province(BK2005216)the Research Foundation of Nanjing University of Aeronautics and Astronautics(NS2010015)~~
文摘The influence of glycol,the main composition of the most frequently used aircraft dicer,on the freeze-thaw durability of high performance concrete(HPC)is investigated.Freeze-thaw durability of HPC is tested by accelerated freeze-thaw test.Four kinds of the solution,i.e.,tap water,3.5% NaCl solution,glycol solutions,and a LBR-A type commercial aircraft deicer are employed.Results show that freeze-thaw durability of HPC exposed to glycol solutions is closely related to the solution concentrations.The failure of HPC exposed to 3.5% glycol solution is similar to that of those exposed to 3.5% NaCl solution,i.e.,serious surface scaling.While the damage of HPC exposed to 12.5%—25% glycol solutions is postponed.Compared with glycol solution,the commercial aircraft deicer has much more negative effects on HPC freeze-thaw durability compared with 3.5% NaCl solution.In the presence of commercial aircraft deicer for HPC subjected to freeze-thaw cycles,the deterioration is mainly due to scaling and spalling.
文摘In order to improve the reliability of the spacecraft micro cold gas propulsion system and realize the precise control of the spacecraft attitude and orbit, a micro-thrust, high-precision cold gas thruster is carried out, at the same time due to the design requirements of the spacecraft, this micro-thrust should be continuous working more than 60 minutes, the traditional solenoid valve used for the thrusts can’t complete the mission, so a long-life micro latching valve is developed as the control valve for this micro thruster, because the micro latching valve can keep its position when it cuts off the outage. Firstly, the authors introduced the design scheme and idea of the thruster. Secondly, the performance of the latching valve and the flow characteristics of the nozzle were simulated. Finally, from the experimental results and compared with the numerical study, it shows that the long-life micro cold gas thruster developed in this paper meets the mission requirements.