Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great significance.To address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al re...Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great significance.To address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al reaction cross section,the activation method and accelerator mass spectrometry(AMS)technique were used to determine the^(27)Al(n,2n)^(26)Al cross section,which could be used as a D-T plasma ion temperature monitor in fusion reactors.At the China Academy of Engineering Physics,neutron activation was performed using a K-400 neutron generator produced by the T(d,n)4He reaction.The^(26)Al∕^(27)Al isotope ratios were measured using the newly installed GYIG 1 MV AMS at the Institute of Geochemistry,Chinese Academy of Sciences.The neutron flux was monitored by measuring the activity of 92mNb produced by the 93Nb(n,2n)92mNb reaction.The measured results were compared with available data in the experimental nuclear reaction database,and the measured values showed a reasonable degree of consistency with partially available literature data.The newly acquired cross-sectional data at 12 neutron energy points through systematic measurements clarified the divergence,which has two different growth trends from the existing experimental values.The obtained results are also compared with the corresponding evaluated database,and the newly calculated excitation functions with TALYS−1.95 and EMPIRE−3.2 codes,the agreement with CENDL−3.2,TENDL-2021 and EMPIRE−3.2 results are generally acceptable.A substantial improvement in the knowledge of the^(27)Al(n,2n)^(26)Al reaction excitation function was obtained in the present work,which will lay the foundation for the diagnosis of the fusion ion temperature,testing of the nuclear physics model,evaluation of nuclear data,etc.展开更多
目的了解2019年中国乙型肝炎的疾病负担情况并对2020—2030年乙型肝炎的疾病负担发展趋势进行预测。方法在2019全球疾病负担研究数据库(Global Burden of Disease 2019,GBD 2019)中下载中国乙型肝炎数据。利用患病率、发病率、死亡率、...目的了解2019年中国乙型肝炎的疾病负担情况并对2020—2030年乙型肝炎的疾病负担发展趋势进行预测。方法在2019全球疾病负担研究数据库(Global Burden of Disease 2019,GBD 2019)中下载中国乙型肝炎数据。利用患病率、发病率、死亡率、伤残调整寿命年(disability-adjusted life year,DALY)、早死损失寿命年(years of life lost,YLL)、伤残损失寿命年(years lived with disability,YLD)及年龄标化率等指标描述2019年中国乙型肝炎的疾病负担情况,利用估计年百分比变化(estimated annual percentage change,EAPC)描述中国乙型肝炎疾病负担1990—2019年的变化趋势。采用R4.2.1构建贝叶斯年龄-时期-队列模型对2020—2030年中国乙型肝炎总体发病、死亡、DALY和YLD情况进行预测。结果1990—2019年中国乙型肝炎的总体疾病负担呈下降趋势,中国乙型肝炎的总体标化患病率为6566.1/10万、标化发病率为1397.3/10万、标化死亡率为8.1/10万、标化DALY率为247.7/10万、标化YLL率为241.5/10万、标化YLD率为6.2/10万,与1990年相比分别下降2.34%、2.35%、4.92%、5.15%、5.20%、2.71%。女性居民的疾病负担指标均低于同时期的男性居民。乙型肝炎的患病率在20~24岁最高,发病率在25~29岁最高,死亡率随着年龄增长而升高。根据贝叶斯模型预测,2020—2030年中国乙型肝炎发病人数约为1486.56万人,死亡人数约为11.18万人,DALY约为634.9万人年,YLD约为12.1万人年。结论尽管在1990—2019年之间中国乙型肝炎疾病负担呈下降趋势,但在2030年消除乙型肝炎病毒这一公共威胁的目标仍然面临挑战。因此,有必要扩大诊断覆盖范围、减轻患者经济负担,进一步推进健康中国建设。展开更多
目的:研究腹腔镜辅助近端胃切除术(laparoscopic-assisted proximal gastrectomy,LAPG)和开腹全胃切除术(open proximalgastrectomy,OPG)治疗SiewertⅡ型和Ⅲ型食管胃结合部腺癌(adenocarcinoma of the esophagogastric junction,AEG)...目的:研究腹腔镜辅助近端胃切除术(laparoscopic-assisted proximal gastrectomy,LAPG)和开腹全胃切除术(open proximalgastrectomy,OPG)治疗SiewertⅡ型和Ⅲ型食管胃结合部腺癌(adenocarcinoma of the esophagogastric junction,AEG)的临床疗效。方法:回顾性分析蚌埠医学院第一附属医院2015年2月至2017年2月收治的116例行近端胃切除的SiewertⅡ型和Ⅲ型AEG患者的临床资料,其中LAPG组48例、OPG组68例。分析两组患者的临床病理特征、术中情况、根治效果与肿瘤复发情况。结果:两组患者手术均顺利完成,无围手术期死亡。LAPG组患者平均手术时间为(3.46±0.46)h,长于OPG组的(2.68±0.68)h;平均术中出血量为(108±46.8)mL,少于OPG组的(236±86.6)mL;胃肠功能恢复时间为(2.56±0.56)d,短于OPG组的(3.82±0.86)d;术后平均住院时间为(12.24±1.86)d,少于OPG组的(14.68±2.89)d;近端切缘(3.06±0.56)cm长于OPG组的(2.38±0.68)cm(均P<0.05)。两组患者的清扫淋巴结数目、远端切缘、术后并发症发生率,差异均无统计学意义(P>0.05)。结论:LAPG在治疗SiewertⅡ型和Ⅲ型AEG患者的根治效果、术后并发症及肿瘤复发方面与开放手术相当;LAPG具有术中出血少、胃肠功能恢复快、住院时间短的优势,近端切缘更长。展开更多
OBJECTIVE To observe the efficacy of high-intensity focused ultrasound (HIFU) in the treatment of late-stage pancreatic cancer. METHODS Sixteen patients with advanced pancreatic cancer received HIFU therapy.Evaluation...OBJECTIVE To observe the efficacy of high-intensity focused ultrasound (HIFU) in the treatment of late-stage pancreatic cancer. METHODS Sixteen patients with advanced pancreatic cancer received HIFU therapy.Evaluation of efficacy was made on the basis of changes in clinical symptoms and variations in the tumor echo and size. RESULTS Clinical symptoms such as pain were significantly alleviated,echo of the tumor was enhanced with B-US and the quality of life such as eating,sleeping and mental status was markedly improved;no serious complications were observed. CONCLUSION The use of HIFU in the treatment of advanced pancreatic cancer is feasible and safe.It is effective in killing the carcinoma cells and alleviating pain.This technique may offer non-invasive therapy for the treatment of patients with late-stage pancreatic cancer.展开更多
Clear cell sarcoma of the kidney （CCSK） is a rare and highly malignant tumor which is usually confused with other kidaey tumors We experienced such a patient and present report this.
The interconnection of wires is an important issue in vacuum-packaged microelectromechanical systems devices because of the difficulties of hermetical sealing and electrical insulation.This paper presents an approach ...The interconnection of wires is an important issue in vacuum-packaged microelectromechanical systems devices because of the difficulties of hermetical sealing and electrical insulation.This paper presents an approach of Au film selective patterning on highly uneven surfaces for wire interconnections of devices in which silicon-oninsulator(SOI)wafers are anodically bonded to glass.The Au film on the handle layer,functioned as an anode,was selectively removed with electrochemical dissolution in a chloride solution.The choice of etchant solution and etching conditions were optimized to improve the process efficiency,resulting in a high yield of gold portions within the via holes for wire interconnection.The proposed wire interconnection technology was employed to fabricate a vacuum-packaged resonant pressure sensor as a proof-of-concept demonstration.Reliable wire bonding and vacuum package were achieved as well as a Q factor that does not decrease over a year.As a platform technology,this method provides a new approach of wire interconnection for vacuum-packaged devices based on SOI–glass anodic bonding.展开更多
Sudden oak death(SOD)is one of the most rapid and destructive forest pathogens,which has caused the death of many host plants in Europe and America.There are currently no cases in China where there are more host plant...Sudden oak death(SOD)is one of the most rapid and destructive forest pathogens,which has caused the death of many host plants in Europe and America.There are currently no cases in China where there are more host plants and a more suitable climate for this pathogen to survive.Therefore,it is vital to discern the potential suitable habitat,quantify the risk levels,and monitor the potential high-risk areas.In this study,we modelled the potential invasion range and risk level of this pathogen at present and in future scenarios in China,using the least correlated components of all the environmental factors based on the Genetic Algorithm for Ruleset Production niche model and GIS analysis.The results indicate that most areas in China are free from a potential SOD risk,and the majority of potential occurrence areas are concentrated in Southern China(Yunnan,Sichuan,Guizhou,Chongqing,Hunan,Fujian).The area of high and extremely high risk in 2050(RCP26,RCP45,RCP60,and RCP85)is larger than that at present.The most susceptible area is Yunnan province with 80%of the area prone to SOD at extremely high risk in present and future scenarios.The results will be important for monitoring potential high-risk areas in the currently uninfected parts of China.展开更多
In this paper,a composite pressure-sensitive mechanism combining diaphragm bending and volume compression was developed for resonant pressure microsensors to achieve high-pressure measurements with excellent accuracy....In this paper,a composite pressure-sensitive mechanism combining diaphragm bending and volume compression was developed for resonant pressure microsensors to achieve high-pressure measurements with excellent accuracy.The composite mechanism was explained,and the sensor structure was designed based on theoretical analysis and finite element simulation.An all-silicon resonant high-pressure microsensor with multiple miniaturized cavities and dual resonators was developed,where dual resonators positioned in two resonant cavities with suitably different widths are used to perform opposite characteristics in pressure and the same characteristics at different temperatures,which can improve pressure sensitivities and realize temperature self-compensation by differential frequency output.The microsensor was fabricated by microfabrication,and the experimental results showed that the sensor had an accuracy of±0.015%full scale(FS)in a pressure range of 0.1~100 MPa and a temperature range of−10~50℃.The pressure sensitivity of the differential frequency was 261.10 Hz/MPa(~2523 ppm/MPa)at a temperature of 20℃,and the temperature sensitivities of the dual resonators were−1.54 Hz/℃(~−14.5 ppm/℃)and−1.57 Hz/℃(~−15.6 ppm/℃)at a pressure of 2 MPa.The differential output had an outstanding stability within±0.02 Hz under constant temperature and pressure.Thus,this research provides a convenient solution for high-pressure measurements because of its advantages,namely,large range,excellent accuracy and stability.展开更多
In this paper,a novel simulation-based evolutionary method is presented for designing parameter-free MEMS structures with maximum degrees of freedom.This novel design method enabled semiautomatic structure evolution b...In this paper,a novel simulation-based evolutionary method is presented for designing parameter-free MEMS structures with maximum degrees of freedom.This novel design method enabled semiautomatic structure evolution by weighing the attributes of each segment of the structure and yielded an optimal design after multiple iterations.The proposed method was utilized to optimize the pressure-sensitive diaphragm of a piezoresistive pressure sensor(PPS).Finite element method(FEM)simulations revealed that,in comparison to conventional diaphragms without islands and with square islands,the optimized diaphragm increased the stress by 10%and 16%and reduced the nonlinearity by 57%and 77%,respectively.These improvements demonstrate the value of this method.Characterization of the fabricated PPS revealed a high sensitivity of 8.8 mV V−1 MPa−1 and a low nonlinearity of 0.058%FS at 20°C,indicating excellent sensor performance.展开更多
This paper presents an on-line measurement method for the diameter and roundness error of balls.An easy-installation rotary scanning system,which integrates the principles of the diameter and the roundness measurement...This paper presents an on-line measurement method for the diameter and roundness error of balls.An easy-installation rotary scanning system,which integrates the principles of the diameter and the roundness measurements,is constructed.The rotary scanning system consists of a rotary stage,a linear stage,and two sensors with a什at probe.Two sensors are initially installed on the linear stage and contact each other.The outputs of two sensors are reset to zero at first.The ball is then mounted on the rotary stage and positioned between two flat probes.The variations of the diameter and the roundness error of the ball at each angular position can be directly recorded by two sensors when the ball is rotated by the rotary stage.Substituting the outputs of two sensors into the proposed mathematical models,the diameter and roundness error can be evaluated.The effects of the alignment error induced by the spindle error of the rotary stage and the titling error and the eccentric error of the ball on the measurement accuracy can be self-separated in the proposed on-line measurement method.A series of experiments are carried out to verify the effectiveness and the capability of the proposed on-line measurement method and the designed rotary scanning system.The designed system is easy to construct both in the laboratory environment and the factory field.展开更多
Extracts from various vegetables and fruits were investigated for their abilities to reduce nitro-polycyclic aromatic hydrocarbons （NPAHs）. The extracts from grape and onion exhibited an interesting selectivity, yie...Extracts from various vegetables and fruits were investigated for their abilities to reduce nitro-polycyclic aromatic hydrocarbons （NPAHs）. The extracts from grape and onion exhibited an interesting selectivity, yielding corresponding hydroxylamines or amines as major products under mild conditions of 30 ℃ and pH 7.0. Grape extracts reduced the 4-nitro-l,8-naphthalic anhydride with the highest conversion rate （〉99%） and the highest ratio of hydro- xylamine to amine （95：5）. In contrast, the onion extracts reduced 4-nitro-l,8-naphthalic anhydride with a conversion rate of 94% and a ratio of hydroxylamine to amine of 8：92. The thiol-reducing agent, 13-mercaptoethanol, and metal cations, Ca2＋ and Mg2＋, greatly increased the reductive efficiency. This work provides an alternative strategy for biotransformation of nitro-polycyclic compounds.展开更多
Recently the alternating twisted trilayer graphene is discovered to exhibit unconventional superconductivity,which motivates us to study the electronic structures and possible correlation effects for this class of alt...Recently the alternating twisted trilayer graphene is discovered to exhibit unconventional superconductivity,which motivates us to study the electronic structures and possible correlation effects for this class of alternating twisted multilayer graphene(ATMG)systems.In this work we consider generic ATMG systems with M-L-N stacking configurations,in which the M(L)graphene layers and the L(N)layers are twisted by an angleθ(−θ).Based on analysis from a simplified k⋅p model approach,we derive generic partition rules for the low-energy electronic structures,which exhibit various band dispersions including two pairs of flat bands and flat bands co-existing with various gapless Fermionic excitations.For a mirror-symmetric ATMG system with doubled flat bands,we further find that Coulomb interactions may drive the system into a state with intertwined electric polarization and orbital magnetization orders,which can exhibit an interaction-driven orbital magnetoelectric effect.展开更多
基金the Open Project of Guangxi Key Laboratory of Nuclear Physics and Nuclear Technology(NLK 2022-04)the Central Government Guidance Funds for Local Scientific and Technological Development,China(No.Guike,ZY22096024)+1 种基金the National Natural Science Foundation of China(12065003)Guangxi Key R&D Project(2023AB07029).
文摘Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great significance.To address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al reaction cross section,the activation method and accelerator mass spectrometry(AMS)technique were used to determine the^(27)Al(n,2n)^(26)Al cross section,which could be used as a D-T plasma ion temperature monitor in fusion reactors.At the China Academy of Engineering Physics,neutron activation was performed using a K-400 neutron generator produced by the T(d,n)4He reaction.The^(26)Al∕^(27)Al isotope ratios were measured using the newly installed GYIG 1 MV AMS at the Institute of Geochemistry,Chinese Academy of Sciences.The neutron flux was monitored by measuring the activity of 92mNb produced by the 93Nb(n,2n)92mNb reaction.The measured results were compared with available data in the experimental nuclear reaction database,and the measured values showed a reasonable degree of consistency with partially available literature data.The newly acquired cross-sectional data at 12 neutron energy points through systematic measurements clarified the divergence,which has two different growth trends from the existing experimental values.The obtained results are also compared with the corresponding evaluated database,and the newly calculated excitation functions with TALYS−1.95 and EMPIRE−3.2 codes,the agreement with CENDL−3.2,TENDL-2021 and EMPIRE−3.2 results are generally acceptable.A substantial improvement in the knowledge of the^(27)Al(n,2n)^(26)Al reaction excitation function was obtained in the present work,which will lay the foundation for the diagnosis of the fusion ion temperature,testing of the nuclear physics model,evaluation of nuclear data,etc.
文摘目的了解2019年中国乙型肝炎的疾病负担情况并对2020—2030年乙型肝炎的疾病负担发展趋势进行预测。方法在2019全球疾病负担研究数据库(Global Burden of Disease 2019,GBD 2019)中下载中国乙型肝炎数据。利用患病率、发病率、死亡率、伤残调整寿命年(disability-adjusted life year,DALY)、早死损失寿命年(years of life lost,YLL)、伤残损失寿命年(years lived with disability,YLD)及年龄标化率等指标描述2019年中国乙型肝炎的疾病负担情况,利用估计年百分比变化(estimated annual percentage change,EAPC)描述中国乙型肝炎疾病负担1990—2019年的变化趋势。采用R4.2.1构建贝叶斯年龄-时期-队列模型对2020—2030年中国乙型肝炎总体发病、死亡、DALY和YLD情况进行预测。结果1990—2019年中国乙型肝炎的总体疾病负担呈下降趋势,中国乙型肝炎的总体标化患病率为6566.1/10万、标化发病率为1397.3/10万、标化死亡率为8.1/10万、标化DALY率为247.7/10万、标化YLL率为241.5/10万、标化YLD率为6.2/10万,与1990年相比分别下降2.34%、2.35%、4.92%、5.15%、5.20%、2.71%。女性居民的疾病负担指标均低于同时期的男性居民。乙型肝炎的患病率在20~24岁最高,发病率在25~29岁最高,死亡率随着年龄增长而升高。根据贝叶斯模型预测,2020—2030年中国乙型肝炎发病人数约为1486.56万人,死亡人数约为11.18万人,DALY约为634.9万人年,YLD约为12.1万人年。结论尽管在1990—2019年之间中国乙型肝炎疾病负担呈下降趋势,但在2030年消除乙型肝炎病毒这一公共威胁的目标仍然面临挑战。因此,有必要扩大诊断覆盖范围、减轻患者经济负担,进一步推进健康中国建设。
文摘目的:研究腹腔镜辅助近端胃切除术(laparoscopic-assisted proximal gastrectomy,LAPG)和开腹全胃切除术(open proximalgastrectomy,OPG)治疗SiewertⅡ型和Ⅲ型食管胃结合部腺癌(adenocarcinoma of the esophagogastric junction,AEG)的临床疗效。方法:回顾性分析蚌埠医学院第一附属医院2015年2月至2017年2月收治的116例行近端胃切除的SiewertⅡ型和Ⅲ型AEG患者的临床资料,其中LAPG组48例、OPG组68例。分析两组患者的临床病理特征、术中情况、根治效果与肿瘤复发情况。结果:两组患者手术均顺利完成,无围手术期死亡。LAPG组患者平均手术时间为(3.46±0.46)h,长于OPG组的(2.68±0.68)h;平均术中出血量为(108±46.8)mL,少于OPG组的(236±86.6)mL;胃肠功能恢复时间为(2.56±0.56)d,短于OPG组的(3.82±0.86)d;术后平均住院时间为(12.24±1.86)d,少于OPG组的(14.68±2.89)d;近端切缘(3.06±0.56)cm长于OPG组的(2.38±0.68)cm(均P<0.05)。两组患者的清扫淋巴结数目、远端切缘、术后并发症发生率,差异均无统计学意义(P>0.05)。结论:LAPG在治疗SiewertⅡ型和Ⅲ型AEG患者的根治效果、术后并发症及肿瘤复发方面与开放手术相当;LAPG具有术中出血少、胃肠功能恢复快、住院时间短的优势,近端切缘更长。
基金a grant from Medical Scientific Research Foundation of Guangdong Province,China (No.A2007481)
文摘OBJECTIVE To observe the efficacy of high-intensity focused ultrasound (HIFU) in the treatment of late-stage pancreatic cancer. METHODS Sixteen patients with advanced pancreatic cancer received HIFU therapy.Evaluation of efficacy was made on the basis of changes in clinical symptoms and variations in the tumor echo and size. RESULTS Clinical symptoms such as pain were significantly alleviated,echo of the tumor was enhanced with B-US and the quality of life such as eating,sleeping and mental status was markedly improved;no serious complications were observed. CONCLUSION The use of HIFU in the treatment of advanced pancreatic cancer is feasible and safe.It is effective in killing the carcinoma cells and alleviating pain.This technique may offer non-invasive therapy for the treatment of patients with late-stage pancreatic cancer.
文摘Clear cell sarcoma of the kidney （CCSK） is a rare and highly malignant tumor which is usually confused with other kidaey tumors We experienced such a patient and present report this.
基金financial supports from National Natural Science Foundation of China (Grant No.61431019,61372054)
文摘The interconnection of wires is an important issue in vacuum-packaged microelectromechanical systems devices because of the difficulties of hermetical sealing and electrical insulation.This paper presents an approach of Au film selective patterning on highly uneven surfaces for wire interconnections of devices in which silicon-oninsulator(SOI)wafers are anodically bonded to glass.The Au film on the handle layer,functioned as an anode,was selectively removed with electrochemical dissolution in a chloride solution.The choice of etchant solution and etching conditions were optimized to improve the process efficiency,resulting in a high yield of gold portions within the via holes for wire interconnection.The proposed wire interconnection technology was employed to fabricate a vacuum-packaged resonant pressure sensor as a proof-of-concept demonstration.Reliable wire bonding and vacuum package were achieved as well as a Q factor that does not decrease over a year.As a platform technology,this method provides a new approach of wire interconnection for vacuum-packaged devices based on SOI–glass anodic bonding.
基金supported by the Natural Science Foundation of China(No.41601368)the National Key Research and Development Program of China(No.2016YFB0501505)the Instrument Development Project of the State Key Laboratory of Remote Sensing Science(No.Y7Y01100KZ)
文摘Sudden oak death(SOD)is one of the most rapid and destructive forest pathogens,which has caused the death of many host plants in Europe and America.There are currently no cases in China where there are more host plants and a more suitable climate for this pathogen to survive.Therefore,it is vital to discern the potential suitable habitat,quantify the risk levels,and monitor the potential high-risk areas.In this study,we modelled the potential invasion range and risk level of this pathogen at present and in future scenarios in China,using the least correlated components of all the environmental factors based on the Genetic Algorithm for Ruleset Production niche model and GIS analysis.The results indicate that most areas in China are free from a potential SOD risk,and the majority of potential occurrence areas are concentrated in Southern China(Yunnan,Sichuan,Guizhou,Chongqing,Hunan,Fujian).The area of high and extremely high risk in 2050(RCP26,RCP45,RCP60,and RCP85)is larger than that at present.The most susceptible area is Yunnan province with 80%of the area prone to SOD at extremely high risk in present and future scenarios.The results will be important for monitoring potential high-risk areas in the currently uninfected parts of China.
基金supported in part by the National Key R&D Program of China under Grant 2022YFB3207300in part by the National Science Fund for Distinguished Young Scholars under Grant 61825107+3 种基金in part by the National Natural Science Foundation of China under Grant 62301536Grant 62121003,Grant 62201549,and Grant U1930206in part by the Youth Innovation Promotion Association CAS under Grant 2023134 and Grant 2022121in part by the Instrument Research and Development of CAS under Grant GJJSTD20210004.
文摘In this paper,a composite pressure-sensitive mechanism combining diaphragm bending and volume compression was developed for resonant pressure microsensors to achieve high-pressure measurements with excellent accuracy.The composite mechanism was explained,and the sensor structure was designed based on theoretical analysis and finite element simulation.An all-silicon resonant high-pressure microsensor with multiple miniaturized cavities and dual resonators was developed,where dual resonators positioned in two resonant cavities with suitably different widths are used to perform opposite characteristics in pressure and the same characteristics at different temperatures,which can improve pressure sensitivities and realize temperature self-compensation by differential frequency output.The microsensor was fabricated by microfabrication,and the experimental results showed that the sensor had an accuracy of±0.015%full scale(FS)in a pressure range of 0.1~100 MPa and a temperature range of−10~50℃.The pressure sensitivity of the differential frequency was 261.10 Hz/MPa(~2523 ppm/MPa)at a temperature of 20℃,and the temperature sensitivities of the dual resonators were−1.54 Hz/℃(~−14.5 ppm/℃)and−1.57 Hz/℃(~−15.6 ppm/℃)at a pressure of 2 MPa.The differential output had an outstanding stability within±0.02 Hz under constant temperature and pressure.Thus,this research provides a convenient solution for high-pressure measurements because of its advantages,namely,large range,excellent accuracy and stability.
基金financially supported by the National Key R&D Program of China(2022YFB3204900)the Youth Innovation Promotion Association CAS(2023134 and 2022121)+1 种基金the Key Technology Team Project of Chinese Academy of Sciences(GJJSTD20210004)the National Natural Science Foundation of China(61825107,U1930206,62121003,and 62201549).
文摘In this paper,a novel simulation-based evolutionary method is presented for designing parameter-free MEMS structures with maximum degrees of freedom.This novel design method enabled semiautomatic structure evolution by weighing the attributes of each segment of the structure and yielded an optimal design after multiple iterations.The proposed method was utilized to optimize the pressure-sensitive diaphragm of a piezoresistive pressure sensor(PPS).Finite element method(FEM)simulations revealed that,in comparison to conventional diaphragms without islands and with square islands,the optimized diaphragm increased the stress by 10%and 16%and reduced the nonlinearity by 57%and 77%,respectively.These improvements demonstrate the value of this method.Characterization of the fabricated PPS revealed a high sensitivity of 8.8 mV V−1 MPa−1 and a low nonlinearity of 0.058%FS at 20°C,indicating excellent sensor performance.
基金the National Natural Science Foundation of China(51905078)National Key Research and Development Program of China(2018YFB2001400,2017YFF0204800)Fundamental Research Funds for the Central Universities(DUT19RC(4)007).
文摘This paper presents an on-line measurement method for the diameter and roundness error of balls.An easy-installation rotary scanning system,which integrates the principles of the diameter and the roundness measurements,is constructed.The rotary scanning system consists of a rotary stage,a linear stage,and two sensors with a什at probe.Two sensors are initially installed on the linear stage and contact each other.The outputs of two sensors are reset to zero at first.The ball is then mounted on the rotary stage and positioned between two flat probes.The variations of the diameter and the roundness error of the ball at each angular position can be directly recorded by two sensors when the ball is rotated by the rotary stage.Substituting the outputs of two sensors into the proposed mathematical models,the diameter and roundness error can be evaluated.The effects of the alignment error induced by the spindle error of the rotary stage and the titling error and the eccentric error of the ball on the measurement accuracy can be self-separated in the proposed on-line measurement method.A series of experiments are carried out to verify the effectiveness and the capability of the proposed on-line measurement method and the designed rotary scanning system.The designed system is easy to construct both in the laboratory environment and the factory field.
基金Project supported by the National Basic Research Program (973) of China (No.2010CB126102)the National Natural Science Foundation of China (No. 31070715)+2 种基金the National High-Tech R&D Program (863) of China (No.2011AA10A204)the National Key Technology R&D Program of China (No.2011BAE06B05)the Fundamental Research Funds for the Central Universities (No.DUT10LK33),China
文摘Extracts from various vegetables and fruits were investigated for their abilities to reduce nitro-polycyclic aromatic hydrocarbons （NPAHs）. The extracts from grape and onion exhibited an interesting selectivity, yielding corresponding hydroxylamines or amines as major products under mild conditions of 30 ℃ and pH 7.0. Grape extracts reduced the 4-nitro-l,8-naphthalic anhydride with the highest conversion rate （〉99%） and the highest ratio of hydro- xylamine to amine （95：5）. In contrast, the onion extracts reduced 4-nitro-l,8-naphthalic anhydride with a conversion rate of 94% and a ratio of hydroxylamine to amine of 8：92. The thiol-reducing agent, 13-mercaptoethanol, and metal cations, Ca2＋ and Mg2＋, greatly increased the reductive efficiency. This work provides an alternative strategy for biotransformation of nitro-polycyclic compounds.
基金This work is supported by the National Key R&D program of China(grant no.2020YFA0309601)the National Science Foundation of China(grant no.12174257)the start-up grant of ShanghaiTech University.
文摘Recently the alternating twisted trilayer graphene is discovered to exhibit unconventional superconductivity,which motivates us to study the electronic structures and possible correlation effects for this class of alternating twisted multilayer graphene(ATMG)systems.In this work we consider generic ATMG systems with M-L-N stacking configurations,in which the M(L)graphene layers and the L(N)layers are twisted by an angleθ(−θ).Based on analysis from a simplified k⋅p model approach,we derive generic partition rules for the low-energy electronic structures,which exhibit various band dispersions including two pairs of flat bands and flat bands co-existing with various gapless Fermionic excitations.For a mirror-symmetric ATMG system with doubled flat bands,we further find that Coulomb interactions may drive the system into a state with intertwined electric polarization and orbital magnetization orders,which can exhibit an interaction-driven orbital magnetoelectric effect.
