检索结果-南通市图书馆

AN ANALYSIS OF THE ELASTIC PLASTIC STRAIN FIELD AHEAD OF A CRACK TIP BY MOIRE’ METHOD

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

天津大学学报 1983年第3期 107-117页

作者： xiao Wei Luo Zhi-shan yuan Fu-xiang

This report presents the observations and measurements of the strain and stress distribution ahead of the tip of a transverse crack in thin aluminium sheets under longitudinal tension by moire’method, In case of small scale yielding the experimental results are in good agreement with the results given by finite element method and the Irwin theory. Hence one can conclude that the experimental technique employed here is reliable, In case of large scale yielding the experimental results shown that the nearer the distance of the line parallel to or perpendicular to the crack from the crack tip, the higher the value of the peak of the stress distribution along that line and the nearer the distance of the peak itself to the tip. However, it is found that the maximum value of the stress does not just appear at the tip of the crack, but at some point a short distance away from the tip, The direction of the crack extension is found to be along the slope of a line which are formed by the furthest points from the crack tip on the iso-effective-stress σ_c contours.

关键词：大学学报天津 AN ANALYSIS OF THE ELASTIC PLASTIC STRAIN FIELD AHEAD OF A CRACK TIP BY MOIRE METHOD

Study of Enhanced Depth Imaging Optical Coherence Tomography in Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Medical Journal 2017年第9期130卷 1042-1048页

作者： xiao-Jing Fang Meng Yu yuan Wu Zi-Hao zhang Wei-Wei Wang zhao-Xia Wang Yun yuan Department of Neurology Peking University First Hospital Beijing 100034 China Department of Ophthalmology Peking University First Hospital Beijing 100034 China State Key Laboratory of Brain and Cognitive Science Beijing MR Center for Brain Research Institute of Biophysics Chinese Academy of Sciences Beijing 100101 China

Background： Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy （CADASIL） is a hereditar5 small artery disease caused by NOTCH3 gene mutation. We performed enhanced depth imaging optical coherence tomography （EDI-OCT） to evaluate the retinal vessel changes in CADASIL patients and assessed their consonance with brain magnetic resonance imaging （MPRI） findings. Methods： Of 27 genetically confirmed patients and an equal number of controls were recruited at the Peking University First ttospital from January 2015 to August 2016. All patients underwent 7T-MRI of the brain. Fazekas score, number of small infarcts and microblecds were evaluated. All patients and controls underwent EDI-OCT to measure subtbveal choroidal thickness （SFCT）, inner and outer diameters as well as arterial and venous wall thickness, and arterial venous ratio of the inner （AVRin） and outer diameters （AVRout）. The relation between retinal vessel changes and Fazekas scores, numbers of small infarcts, or microbleeds was analyzed. Paired t-test was used to compare the SFCT and retinal vessel measurement data between patients and controls. Spearman＇s correlation was used to investigmc the correlation between retinal vessel changes and MRI lesions. Results： In CADASI L patients, mean SFCT （268.37 ± 46.50 μm） and mean arterial inner diameter （93.46 ± 9.70 gin） were signilicantly lower than that in controls （P 〈 0.00 ）, P = 0.048, respectively）. Mean arterial outer diameter （ 131.74 ± 10.87 μm）, venous inner （ 128.99 ± 13.62 μm） and outer diameter （ 164.82 ±14.77 μm）, and mean arterial （ 19.13 ±1.85 μm） and venous （ 17.91 ±2.76 μm） wall thickness were significantly higher than that in controls （P = 0.023, P 0.004, P 〈 0.001, P 〈 0.001, respectively）. Arterial inner diameter （r= - 0.39, P 0.044）] AVRin （r -0.65, P 〈 0.001）, and AVR,, （r =0.56, P - 0.002） showed a negative correlation with the number of small infarcts. Venous inner diameter （rs=0.46, P= 0.016） showed a p

关键词： Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy: Magnetic Resonancehnaging Optical Coherence Tomography Retinal Vessels

晶闸管阀过电流试验装置过电压保护策略的研究

在线全文

学校读者我要写书评

暂无评论

中国电机工程学报 2006年第13期26卷 56-61页

作者：贺之渊邓占锋查鲲鹏汤广福中国电力科学研究院北京市海淀区100085

介绍了我国第1套适用于灵活交流输电系统(FACTS)和高压直流输电系统(HVDC)的高压晶闸管阀过电流试验装置的基本原理。针对试验过程中可能产生的瞬时过电压和故障过电压分别建立了数学和仿真模型,分析了过电压的产生机理、危害及特点。... 详细信息

介绍了我国第1套适用于灵活交流输电系统(FACTS)和高压直流输电系统(HVDC)的高压晶闸管阀过电流试验装置的基本原理。针对试验过程中可能产生的瞬时过电压和故障过电压分别建立了数学和仿真模型,分析了过电压的产生机理、危害及特点。在上述分析的基础上对不同的保护策略进行比较,提出阻容吸收回路与BOD(break over diode)触发晶闸管阀相结合的新型过电压保护策略,理论分析和仿真结果都证明所提出的保护策略的正确性和有效性,从而确保过电流试验装置的安全可靠运行。

关键词：过电压过电流试验晶闸管阀保护策略

A Novel Approach to Bioleach Soluble Phosphorus from Rock Phosphate

在线全文

学校读者我要写书评

暂无评论

过程工程学报 2007年第2期7卷 310-316页

作者：池汝安肖春桥黄晓慧王存文吴元欣 Hubei Key Laboratory of Novel Chemical Reactor and Green Chemical Technology Wuhan Institute of Technology

A novel approach to bioleach soluble phosphorus from rock phosphate,involving the bio-oxidation of pyrite by adaptated Acidithiobacillus ferrooxidans(At.f)and the product of sulfuric acid to dissolve rock phosphate,has been proposed in this *** soluble phosphorus could be leached more effectively in the presence of pyrite by At.f than that leached directly by sulfuric *** optimal technological parameters are *** highest phosphorus leaching rate is 9.00% when the culture substrate is the mixture of FeSO_47H_2O and pyrite,the phosphorus leaching rate is 8.00% when the initial pH and culture time are 2.5 and 5 d,*** optimal rock phosphate particle size is 0.05 mm for the leaching of *** bigger the grains of pyrite,the lower the phosphorus leaching *** bacterium At.f should be appropriately adaptated,which makes it easier to bioleach soluble phosphorus from rock phosphate.

关键词：微生物化学生物技术免疫力生物知识

Inhaler use in chronic obstructive pulmonary disease patients: a meta-analysis

在线全文

学校读者我要写书评

暂无评论

Frontiers of Nursing 2022年第4期9卷 343-352页

作者： Li-Juan Zhou Xian-Xiu Wen Rong Jiang Huang-yuan Zhou Yan Li xiao-Rang Mao Mei Lan Department of Respiration and Critical Care Medicine Sichuan Provincial People’s HospitalUniversity of Electronic Science and Technology of ChinaChengduSichuan 610000China Department of Nursing Sichuan Provincial People’s HospitalUniversity of Electronic Science and Technology of ChinaChengduSichuan 610000China School of Medicine University of Electronic Science and Technology of ChinaChengduSichuan 610000China Department of Central Sichuan Provincial People’s HospitalUniversity of Electronic Science and Technology of ChinaChengduSichuan 610000China Department of Sichuan Provincial People’s Hospital University of Electronic Science and Technology of ChinaChengduSichuan 610000China

Objective: To evaluate errors in the use of inhalation techniques in patients with chronic obstructive pulmonary disease(COPD), and to provide evidence for improving the effectiveness of ***: A meta-analysis was performed after searching for literature at Pub Med, Embase, Web of Science, Cochrane Library, CINAHL, China National Knowledge Infrastructure(CNKI), Wan Fang, VIP, and Sion Med databases which were published from January 2011 to October 2020, addressing errors in the use of inhalation technologies for the treatment of COPD. After reviewing the literature, extracting per tinent information, and evaluating the risk of bias for the included studies, statistical analysis was performed using Stata ***: Thir teen papers(12 in English and 1 in Chinese), representing 2527 patients, met the search criteria and were included in the meta-analysis. The results showed that the combined effect size of COPD patients making at least one operational error was 76%(95% CI: 0.69–0.83). The error rate varied with inhaler type;the combined effect size error for powered inhalers was 66%(95% CI: 0.57, 0.74), 67%(95% CI. 0.57, 0.77) for metered-dose inhalers(MDI), and 51%(95% CI: 0.38, 0.64) for soft mist inhalers(SMI).Conclusions: More than 75% of patients with COPD were unable to consistently use inhalers correctly, with the highest error rate for MDI. Therefore, health care providers must continue to educate patients on proper use of inhaler, ensuring their correct use and reducing the risk of acute COPD exacerbations.

关键词： chronic obstructive pulmonary disease inhaler handling errors inhaler technique medications meta-analysis

中国数据要素规模估计与结构分析——基于信息价值链的视角

在线全文

学校读者我要写书评

暂无评论

当代财经 2024年第4期 3-16页

作者：徐翔田晓轩厉克奥博陈斌开中央财经大学经济学院北京102206 清华大学社会科学学院北京100084 清华大学中国经济思想与实践研究院北京100084

数据是数字经济时代的关键生产要素。对数据要素规模及其收入分配进行估计与分析,有助于正确理解当前我国的数字经济发展水平,为相关研究提供数据基础。现有研究大多重视数据要素的生产成本或市场价值,缺乏基于信息价值链视角构建的、... 详细信息

数据是数字经济时代的关键生产要素。对数据要素规模及其收入分配进行估计与分析,有助于正确理解当前我国的数字经济发展水平,为相关研究提供数据基础。现有研究大多重视数据要素的生产成本或市场价值,缺乏基于信息价值链视角构建的、充分考虑数据价值形成与释放全过程的估计方法。通过改良现有估计方法并对2012—2019年各省份数据要素投资进行测算的结果表明,2019年中国的数据要素投资达到2.05万亿元,较2012年的8712亿元扩大1.35倍,年均增速达13.02%;中国数据要素投资表现出显著的区域不均等特征,将可能导致各省份数据要素存量差距不断拉大,不利于数字经济高质量发展。以上结果充分说明,数据要素在经济增长与初次收入分配中的重要性均不断提升,相关基础制度与政策措施应尽快落地。

关键词：数据要素就业人员工资固定资产投资收入分配

Computational Analysis of Drought Stress-Associated miRNAs and miRNA Co-Regulation Network in Physcomitrella patens

在线全文

学校读者我要写书评

暂无评论

Genomics, Proteomics & Bioinformatics 2011年第1期9卷 37-44页

作者： Ping Wan Jun WH yuan Zhou Junshu xiao Jie Feng Weizhong zhao Shen Xian Guanglong Jiang Jake Y.Chen College of Life Sciences Capital Normal University Beijing 100048 China School of Mathematical Sciences Capital Normal University Beijing 100048 China School of Informatics Indiana University-Purdue University Indianapolis IN46202 USA Department of Computer & Information Science Purdue University 1N47907 USA Indiana Center for Systems Biology and Personalized Medicine IN 46202 USA

miRNAs are non-coding small RNAs that involve diverse biological processes. Until now, little is known about their roles in plant drought resistance. Physcomitrella patens is highly tolerant to drought; however, it is not clear about the basic biology of the traits that contribute P. patens this important character. In this work, we discovered 16 drought stress-associated miRNA （DsAmR） families in P. patens through computational analysis. Due to the possible discrepancy of expression periods and tissue distributions between potential DsAmRs and their targeting genes, and the existence of false positive results in computational identification, the prediction results should be examined with further experimental validation. We also constructed an miRNA co-regulation network, and identi- fied two network hubs, miR902a-Sp and miR414, which may play important roles in regulating drought-resistance traits. We distributed our results through an online database named ppt-miRBase, which can be accessed at http：/***/ppt_miRBase/***. Our methods in finding DsAmR and miRNA co-regulation network showed a new direction for identifying miRNA functions.

关键词： miRNA drought stress co-regulation network Physcomitrella patens

Expression and activity of inducible nitric oxide synthase and endothelial nitric oxide synthase correlate with ethanolinduced liver injury

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2006年第15期12卷 2375-2381页

作者： Guang-Jin yuan xiao-Rong Zhou Zuo-Jiong Gong Pin zhang xiao-Mei Sun Shi-Hua Zheng Department of Infectious Diseases Renmin Hospital of Wuhan UniversityWuhan 430060 Hubei Province China

AIM： To study the expression and activity of inducible nitric oxide synthase （iNOS） and endothelial nitric oxide synthase （eNOS） in rats with ethanol-induced liver injury and their relation with liver damage, activation of nuclear factor-KB （NF-κB） and tumor necrosis factor-α （TNF-α） expression in the liver. METHODS： Female Sprague-Dawley rats were given fish oil （0.5 mL） along with ethanol or isocaloric dextrose daily via gastrogavage for 4 or 6 wk. Liver injury was assessed using serum alanine aminotransferase （ALT） activity and pathological analysis. Liver malondialdehyde （MDA）, nitric oxide contents, iNOS and eNOS activity were determined. NF-κB p65, iNOS, eNOS and TNF-α protein or mRNA expression in the liver were detected by immunohistochemistry or reverse transcriptase-polymerase chain reaction （RT-PCR）. RESULTS： Chronic ethanol gavage for 4 wk caused steatosis, inflammation and necrosis in the liver, and elevated serum ALT activity. Prolonged ethanol administration （6 wk） enhanced the liver damage. These responses were accompanied with increased lipid peroxidation, NO contents, iNOS activity and reduced eNOS activity. NF-κB p65, iNOS and TNF-α protein or mRNA expression were markedly induced after chronic ethanol gavage, whereas eNOS mRNA expression remained unchanged. The enhanced iNOS activity and expression were positively correlated with the liver damage, especially the necro-inflammation, activation of NF-KB, and TNF-α mRNA expression. CONCLUSION： iNOS expression and activity are induced in the liver after chronic ethanol exposure in rats, which are correlated with the liver damage, especially the necro-inflammation, activation of NF-KB and TNF-α expression, eNOS activity is reduced, but its mRNA expression is not affected.

关键词： Alcoholic liver disease Inducible nitric oxide synthase Endothelial nitric oxide synthase Nuclear factor-κB

苯并噻唑基共价有机框架材料的制备及其对水中铜离子的检测和吸附

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

化学试剂 2024年第10期46卷 14-22页

作者：周壮壮麻丽媛左佳灵丁镠李笑马雪浩金洗郎西安邮电大学计算机学院陕西西安710021 西安工业大学材料与化工学院陕西西安710021 陕西理工大学材料科学与工程学院陕西汉中723001

铜(Cu)元素对人体起着至关重要的作用,水中铜离子的检测是环境监测的重要内容。以4,4′,4″-(1,3,5-三嗪-2,4,6-三基)三苯甲醛和2,5-二氨基-1,4-苯二硫酚二盐酸盐为原料通过两步法合成了一种双功能共价有机框架材料(COF-TFPT-DBD)。COF-... 详细信息

铜(Cu)元素对人体起着至关重要的作用,水中铜离子的检测是环境监测的重要内容。以4,4′,4″-(1,3,5-三嗪-2,4,6-三基)三苯甲醛和2,5-二氨基-1,4-苯二硫酚二盐酸盐为原料通过两步法合成了一种双功能共价有机框架材料(COF-TFPT-DBD)。COF-TFPT-DBD具有优良的物理化学稳定性、较大的比表面积(382.91 m^(2)/g)以及优异的荧光性能。COF-TFPT-DBD对Cu^(2+)具有良好的选择性和灵敏度,在10~40μmol/L浓度范围内呈现良好的线性关系(R^(2)=0.988),较低的检测限(250 nmol/L)。此外,在室温条件下对Cu^(2+)的最大吸附量达到152 mg/g(pH 7),且可以循环使用3次以上。X射线光电子能谱和傅里叶红外光谱证实了COF-TFPT-DBD中功能单元与Cu^(2+)之间的相互作用。这些结果表明,该共价有机框架材料在水中铜离子的检测和高效富集方面具有潜在的应用前景。

关键词：共价有机框架苯并噻唑铜离子识别吸附循环