检索结果-南通市图书馆

Rapid synthesis of Ti(C,N) powders by mechanical alloying and subsequent arc discharging

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2011年第7期21卷 1545-1549页

作者：袁泉郑勇余海州南京航空航天大学材料科学与技术学院南京210016 三峡大学机械与材料学院宜昌443002

Ti（C,N） powders were synthesized by mechanical alloying （MA） from a mixture of pure titanium and graphite under a nitrogen atmosphere in a planetary *** of arc discharging on phase transformation and microstructure of MA powders milled for 1-7 h were *** results show that Ti（C,N） powders were prepared after mechanical milling for 1 h and subsequent arc discharge treatment,whereas the synthesis reaction did not occur in 7 h by mechanical milling *** ions produced during arc discharging interacted with powder particles and accelerated the diffusion of atoms and the nucleation on the surface of the as-milled powder,which results in fast synthesis of Ti（C,N） *** formation mechanisms of the two synthesis processes are self-propagating reactive synthesis.

关键词： Ti(C N) powders mechanical alloying self-propagating reactive synthesis

A data-driven method to predict future bottlenecks in a remanufacturing system with multi-variant uncertainties

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2022年第1期29卷 129-145页

作者： XUE zheng LI Tao PENG Shi-tong ZHANG Chao-yong ZHANG Hong-chao School of Mechanical Engineering Dalian University of TechnologyDalian 116024China Department of Mechanical Engineering Shantou UniversityShantou 515000China School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430000China Department of Industrial Manufacturing&Systems EngineeringTexas Tech UniversityLubbockTX 79409 USA

The remanufacturing system is remolding the manufacturing industry by bringing scrapped products back to such a condition that reintegrated performance is just as good as *** remanufacturing environment is featured by a far deeper level of uncertainty than new manufacturing,such as probabilistic routing files,and highly variable processing *** stochastic disturbances result in the production bottlenecks,which constrain the productivity of the job *** uncertainties in the remanufacturing process cause the bottlenecks to shift when the workshop is *** this outstanding problem,many researchers try to optimize the production process to mitigate dynamic bottlenecks toward a balanced *** paper proposes a data-driven method to predict bottlenecks in the remanufacturing system with multi-variant ***,discrete event simulation technology is applied to establish a simulation model of the remanufacturing production line and calculate the bottleneck index to identify ***,a data-driven method,auto-regressive moving average(ARMA)model is employed to predict the bottlenecks in the system based on real-time data captured by the Arena ***,the proposed prediction method is verified on real data from the automobile engine remanufacturing production line.

关键词： bottleneck identification dynamic bottleneck remanufacturing system auto-regressive moving average model

在线全文

学校读者我要写书评

暂无评论

肾上腺静脉采血

介入放射学杂志 2009年第8期18卷 631-635页

作者：孙勇倪才方苏州大学附属第一医院介入科苏州215000

肾上腺静脉采血是通过导管选择性插至肾上腺静脉内采取血样的一种介入检查方法,主要用于原发性醛固酮增多症(PA)的鉴别诊断。熟悉肾上腺静脉解剖及变异、术前充分准备、熟练的操作技术,可快速获得足量有效的样本,减少并发症。肾上腺静... 详细信息

肾上腺静脉采血是通过导管选择性插至肾上腺静脉内采取血样的一种介入检查方法,主要用于原发性醛固酮增多症(PA)的鉴别诊断。熟悉肾上腺静脉解剖及变异、术前充分准备、熟练的操作技术,可快速获得足量有效的样本,减少并发症。肾上腺静脉采血诊断准确、技术可行,应成为明确PA病因的常规检查手段。

关键词：肾上腺静脉采血介入并发症

在线全文

学校读者我要写书评

暂无评论

尾矿坝漫顶溃坝事故树分析

东北大学学报（自然科学版） 2010年第6期31卷 890-893页

作者：魏勇许开立郑欣东北大学资源与土木工程学院辽宁沈阳110004

根据汛期尾矿坝溃坝的一些典型事例,概括出了导致尾矿坝漫顶溃坝的基本事件.应用事故树分析中的最小割集、最小径集及结构重要度,对尾矿坝漫顶溃坝事故进行了研究.结果表明:导致尾矿坝漫顶溃坝的最小割集合有54个,说明尾矿坝漫顶溃坝容... 详细信息

根据汛期尾矿坝溃坝的一些典型事例,概括出了导致尾矿坝漫顶溃坝的基本事件.应用事故树分析中的最小割集、最小径集及结构重要度,对尾矿坝漫顶溃坝事故进行了研究.结果表明:导致尾矿坝漫顶溃坝的最小割集合有54个,说明尾矿坝漫顶溃坝容易发生;防止尾矿坝漫顶溃坝的最小径集合有4个;通过计算基本事件的结构重要度表明,存在坝体隐患、坝体设计不当、坝体施工差、未作日常维护、地质条件差等都是控制尾矿坝漫顶溃坝事故发生的关键.

关键词：尾矿坝漫顶溃坝事故树基本事件

Purification and identification of simian parvovirus protein Vp2 expressed in ***

在线全文

学校读者我要写书评

暂无评论

Journal of Microbiology and Immunology 2005年第3期3卷 219-223页

作者： zheng WEN LIU yong LIE CHU KEVIN E.BROWN Department of Infectious Diseases First Hospital of Xi-an Jiaotong University Xi-an P. R. China Department of Microbiology Medical School Xi-an Jiaotong University Xi-an P. R. China Virus Discovery Group National Heart Lung and Blood Institute NIH Bethesda MD USA

To purify and identify the simian parvovirus （SPV） protein Vp2 expressed in E. coli, fusion protein of SPV Vp2 was expressed in E. coli DHSα competent cells transformed with vector pThioHis AVp2, and the new bacterial protein extraction reagent was used to extract the protein. Detergents with different characteristics were used to solubilize the fusion protein, and metal chelating resin （ProBond） with a continuous elusion polyacrylamide gel electrophoresis procedure was employed to purify the fusion protein. SDS-PAGE gel stained with coomassie blue and Western-blotting probed with anti-thio and anti-SPV Vp2 antibodies were used to identify the specificity of the expressed and purified fusion proteins. It was found that the SPV Vp2 protein expressed in E. coli was highly insoluble, and could not be solublized by the commonly used detergent. However, 6 M urea could solubilize the fusion proteins and was then employed for the further purification procedure, but metal chelating resin could not be used for this procedure, because of the loss of the tertiary structure of HP-thiaoredoxin and the metal-binding domain. The technique with continuous elusion polyacrylamide gel electrophoresis yielded a homogenous protein with a single band on the gel stained with coomassie blue and retained reactivity with anti-thio or anti-SPV Vp2 antibodies. It is evident that this technique with successful purification of SPV Vp2 protein has practical significance for the further investigation on the simian parvovirus infection.

关键词： Simian parvovirus Protein expression Protein purification

基于新型主成分加权平均归一化法优选水下重力匹配导航适配区

在线全文

学校读者我要写书评

暂无评论

地球物理学报 2019年第9期62卷 3269-3278页

作者：李钊伟郑伟房静吴凡中国空间技术研究院钱学森空间技术实验室北京100094 辽宁工程技术大学测绘与地理科学学院辽宁阜新123000 河南理工大学测绘与国土信息工程学院河南焦作454000 江苏海洋大学测绘与海洋信息学院江苏连云港222005 中国科学院测量与地球物理研究所大地测量与地球动力学国家重点实验室武汉430077 中国电子科技集团公司第三十九研究所西安710065

本文开展了水下潜器重力匹配导航的匹配区适配性评价研究.第一,本文综合考虑了重力异常标准差、坡度标准差、粗糙度、重力异常差异熵、分形维数等重力场主要特征参数,联合主成分分析准则和加权平均原理,提出了新型主成分加权平均归一化... 详细信息

本文开展了水下潜器重力匹配导航的匹配区适配性评价研究.第一,本文综合考虑了重力异常标准差、坡度标准差、粗糙度、重力异常差异熵、分形维数等重力场主要特征参数,联合主成分分析准则和加权平均原理,提出了新型主成分加权平均归一化法;第二,基于新型主成分加权平均归一化法,计算可评价重力异常基准图各区域匹配效果的总体特征参数指标,依据总体特征参数指标进行优良适配区、一般适配区和非适配区划分;第三,在相同条件下,在划分的优良适配区、一般适配区和非适配区内,分别进行重力匹配数值模拟验证比较,结果表明,优良适配区的重力匹配效果显著,匹配概率约为98%,匹配稳定性高,位置误差小于1个重力异常基准图格网.

关键词：主成分加权平均归一化法水下重力匹配导航重力适配性海洋重力异常总体特征参数指标

Identifying the Risk of SARS-CoV-2 Infection and Environmental Monitoring in Airborne Infectious Isolation Rooms(AIIRs)

在线全文

学校读者我要写书评

暂无评论

Virologica Sinica 2020年第6期35卷 785-792页

作者： Zhi-Gang Song Yan-Mei Chen Fan Wu Lin Xu Bang-fang Wang Lei Shi Xiao Chen Fa-Hui Dai Jia-Lei She Jian-Min Chen Edward CHolmes Tong-Yu Zhu yong-Zhen Zhang Shanghai Public Health Clinical Center State Key Laboratory of Genetic EngineeringSchool of Life SciencesFudan UniversityShanghai 201508China College of Marine Sciences South China Agricultural UniversityGuangzhou 510642China Department of Environmental Science and Engineering Fudan UniversityShanghai 200438China Marie Bashir Institute for Infectious Diseases and Biosecurity School of Life and Environmental Sciences and School of Medical SciencesThe University of SydneySydneyNSW 2006Australia

Healthcare workers(HCWs)are at high risk of occupational exposure to the new pandemic human coronavirus,SARSCoV-2,and are a source of nosocomial transmission in airborne infectious isolation rooms(AIIRs).Here,we performed comprehensive environmental contamination surveillance to evaluate the risk of viral transmission in AIIRs with 115 rooms in three buildings at the Shanghai Public Health Clinical Center,Shanghai,during the treatment of 334 patients infected with *** results showed that the risk of airborne transmission of SARS-CoV-2 in AIIRs was low(1.62%,25/1544)due to the directional airflow and strong environmental hygiene ***,we detected viral RNA on the surface of foot-operated openers and bathroom sinks in AIIRs(viral load:55.00–3154.50 copies/mL).This might be a source of contamination to connecting corridors and object surfaces through the footwear and gloves used by *** risk of infection was eliminated by the use of disposable footwear covers and the application of more effective environmental and personal hygiene *** the help of effective infection control procedures,none of 290 HCWs was infected when working in the AIIRs at this *** study has provided information pertinent for infection control in AIIRs during the treatment of COVID-19 patients.

关键词： SARS-CoV-2 COVID-19 Nosocomial transmission AIIRs Environmental sampling

在线全文

学校读者我要写书评

暂无评论

离散小波变换快速卷积算法研究

振动与冲击 2013年第23期32卷 186-190,207页

作者：秦毅王腾毛永芳重庆大学机械传动国家重点实验室重庆400044 重庆大学自动化学院重庆400044

传统的离散小波变换(Discrete Wavelet Transform,DWT)卷积算法通常采用延拓方法来解决边界效应,处理速度会受到一定影响。为了进一步提高使用DWT的实时性,提出一种新的离散卷积快速实现算法。该方法利用前后端卷积结果对边界小波系数... 详细信息

传统的离散小波变换(Discrete Wavelet Transform,DWT)卷积算法通常采用延拓方法来解决边界效应,处理速度会受到一定影响。为了进一步提高使用DWT的实时性,提出一种新的离散卷积快速实现算法。该方法利用前后端卷积结果对边界小波系数进行校正,有效地解决了卷积运算中的边界效应问题,并减少了计算量。仿真试验和工程应用结果表明该算法能用于分析平稳信号和非平稳信号,具有很高的分解和重构精度以及很好的边界处理性能,并且计算速度比传统方法有较大提高,具有显著的工程应用价值。

关键词：小波变换卷积边界效应 FFT算法理想重建

中国农业保险补贴政策绩效评估:来自多期DID的经验证据

在线全文

学校读者我要写书评

暂无评论

中央财经大学学报 2020年第9期 24-34页

作者：王立勇房鸿宇谢付正中央财经大学国际经济与贸易学院中央财经大学统计与数学学院中国社会科学院

笔者以我国农业保险补贴政策试点为一项准自然实验,借助多期DID、连续型DID和三重差分模型等方法,从农民人均纯收入、农民家庭经营纯收入视角研究了我国农业保险补贴政策的效果,且剖析这一政策效果的异质性特征和内在影响机理。研究结... 详细信息

笔者以我国农业保险补贴政策试点为一项准自然实验,借助多期DID、连续型DID和三重差分模型等方法,从农民人均纯收入、农民家庭经营纯收入视角研究了我国农业保险补贴政策的效果,且剖析这一政策效果的异质性特征和内在影响机理。研究结果表明:我国农业保险补贴政策对农民人均纯收入和农民家庭经营纯收入有显著正向影响,农业保险补贴政策显著提高了政策试点区域的农民人均纯收入和农民家庭经营纯收入;我国农业保险补贴政策的效果存在显著的异质性特征,中、西部地区的农业保险补贴政策对农民收入的提升效果明显高于东部地区,受灾程度较大地区的农业保险补贴政策的效果更加明显,收入提升效果几乎是受灾程度较小地区的两倍多;农业保险补贴政策显著提升了农户对农业保险的参与度,促进了农业保险发展,从而提升了农民收入。

关键词：准自然实验三重差分多期DID 连续型DID 农业保险补贴政策