检索结果-南通市图书馆

Polymorphisms of angiotensin-converting enzyme 2 gene confer a risk to lone atrial fibrillation in Chinese male patients

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

Chinese Medical Journal 2013年第24期126卷 4608-4611页

作者： WANG Shu-xia TAO Tao fu zhi-qing xie Xiang-zhu WANG Hao WANG Yu-tang First Geriatric Cardiology Department Chinese People's LiberationArmy General Hospital Beijing 100853 China~

Background Growing epidemiologic evidence has indicated that genetics can predispose individuals to the occurrence of lone atrial fibrillation （AF）. The angiotensin-converting enzyme 2 （ACE2） gene has been established to be associated with hypertension and left ventricular hypertrophy. The objective of our study was to investigate the association of ACE2 gene polymorphisms with lone AF. Methods A total of 265 consecutive lone AF patients and 289 healthy controls were successfully investigated. The polymorphisms rs2106809 and rs2285666 were genotyped by polymerase chain reaction （PCR） and direct sequencing. A Logistic regression model was used to determine the odds ratio （OR） and 95% confidence intervals （CO of variations of ACE2 for lone AF. Results The T allele of rs2106809 conferred an increased risk for lone AF （OR 1.24, 95% CI 1.01-1.52, P=0.03） in males after adjustment for conventional risk factors. SNP at rs2285666 in males was not significantly different between AF patients and controls. No association was found between the two polymorphisms in the female population with lone AF. After （36.3±4.5） months of follow-up, the end point data were obtained： death （cardiac and noncardiac）, ischemic stroke, and heart failure. In the male subgroup, the associations between rs2106809 T male carriers and combined end points including ischemic stroke, heart failure, and death in our study were of significance （OR 3.6, 95% CI 1.0-13.1, P=-0.04）. Conclusions The results indicate that polymorphism at ACE2 gene is associated with male lone AF in a Chinese Han population. Lone AF males who *** the. rs2106809T ***, are. associate.d with adverse cardiac, ***

关键词： polymorphism ACE2 gene lone atrial fibrillation follow up

在线全文

学校读者我要写书评

暂无评论

摩擦因数对钢丝绳有限元分析结果的影响

机械设计 2018年第4期35卷 92-96页

作者：杜文正马保珠曹大志付广磊谢政火箭军工程大学二系陕西西安710025

钢丝绳在使用过程中,钢丝之间的摩擦因数会逐渐增大。文中以某型起重机所用6×36+WS结构的钢丝绳为研究对象,仿真分析了其在不同摩擦因数下的应力和变形分布,探究了摩擦因数对其应力和变形的影响。利用Solid Works软件建立了钢丝绳三维... 详细信息

钢丝绳在使用过程中,钢丝之间的摩擦因数会逐渐增大。文中以某型起重机所用6×36+WS结构的钢丝绳为研究对象,仿真分析了其在不同摩擦因数下的应力和变形分布,探究了摩擦因数对其应力和变形的影响。利用Solid Works软件建立了钢丝绳三维模型,导入ABAQUS中,建立钢丝绳有限元模型。在相同的轴向荷载下,仿真分析了4种不同的摩擦因数对钢丝绳应力和变形的影响。结果表明,钢丝绳Von-Mises应力随着摩擦因数的增大而增大,变形量U随着摩擦因数的增大而小幅度减小,说明摩擦因数是影响钢丝绳寿命的重要因素,钢丝绳使用过程中应注意润滑。

关键词：钢丝绳有限元摩擦因数应力变形

Integrated Equipment Health Prognosis Considering Crack Initiation Time Uncertainty and Random Shock

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2017年第6期30卷 1383-1395页

作者： fu-Qiong Zhao Ming-Jiang xie zhi-Gang Tian Yong Zeng Department of Mechanical Engineering University of Alberta Edmonton T6G 2G8 Canada Concordia Institute for Information Systems Engineering Concordia University Montreal H3G 2Wl Canada

With integrated equipment health prognosis, both physical models and condition monitoring data are utilized to achieve more accurate prediction of equipment remaining useful life （RUL）. In this paper, an integrated prognostics method is proposed to account for two important factors which were not considered before, the uncertainty in crack initiation time （CIT） and the shock in the degradation. Prognostics tools are used for RUL pre- diction starting from the CIT. However, there is uncertainty in CIT due to the limited capability of existing fault detection tools, and such uncertainty has not been explic- itly considered in the literature for integrated prognosis. A shock causes a sudden damage increase and creates a jump in the degradation path, which shortens the total lifetime, and it has not been considered before in the integrated prognostics framework either. In the proposed integrated prognostics method, CIT is considered as an uncertain parameter, which is updated using condition monitoring data. To deal with the sudden damage increase and reduction of total lifetime, a virtual gradual degradation path with an earlier CIT is introduced in the proposed method. In this way, the effect of shock is captured through identifying an appropriate CIT. Examples of gear prog- nostics are given to demonstrate the effectiveness of the proposed method.

关键词： Crack initiation time Shock Uncertaintyquantification Integrated prognostics Failure timeprediction Bayesian inference Gears Fatigue crack

基于DMD的阿达玛变换型近红外光谱仪快速处理系统设计与实现

在线全文

学校读者我要写书评

暂无评论

光谱学与光谱分析 2025年第1期45卷 133-138页

作者：王硕谢振坤魏志鹏长春理工大学高功率半导体激光国家重点实验室吉林长春130022 长春理工大学中山研究院广东中山528437

数字微镜器件(DMD)的近红外光谱仪,具有波长重复性好、分辨率高和抗振动性好等优点,广泛应用于食品安全和农业生产等领域的研究。随着DMD的微小型近红外光谱仪发展逐渐趋于成熟,仪器的成本和性能仍然是研发的关键。尽管大部分将重点放... 详细信息

数字微镜器件(DMD)的近红外光谱仪,具有波长重复性好、分辨率高和抗振动性好等优点,广泛应用于食品安全和农业生产等领域的研究。随着DMD的微小型近红外光谱仪发展逐渐趋于成熟,仪器的成本和性能仍然是研发的关键。尽管大部分将重点放在了软件开发和检测方法的研究,而仪器硬件的处理速度至关重要。只有确保光谱仪能够快速准确的采集并传输数据,才能有效实现光谱分析。在多数研究中,阿达玛矩阵的生成和解码工作通常由上位机完成,并通过FLASH存储的方式导入模板。这种方式可能会限制采集一幅完整光谱数据的时间效率。为了提高光谱采集速度和信噪比,提出一种高速驱动DMD和快速数据采集的方法,并基于DMD微小型近红外光谱仪设计一套硬件电路系统。采用现场可编辑门阵列(FPGA)和ARM的架构,创新性地实现了奇偶阿达玛模板的生成与解码过程在嵌入式系统底层执行,加快了光谱分析的速度并提高信噪比。通过与市面上DMD型光谱仪对比,研究结果显示,所研发的光谱仪完成单次光谱的采集时间仅需214 ms,相比商用DMD型光谱仪,采集效率提升了4倍。在同等3 s的采集时间内,所研发光谱仪的信噪比为4600,相比商用DMD型光谱仪,信噪比提升了1.5倍。通过所研发的光谱仪对油菜籽样品进行光谱扫描,分析了油菜籽的脂肪、蛋白质和水分的含量,并采用偏最小二乘回归(PLSR)建立了相应的模型。油菜籽脂肪含量的校正相关系数为0.9865、预测相关系数为0.9672;蛋白质含量的校正相关系数为0.9854、预测相关系数系数为0.9636;水分含量的校正相关系数为0.9875、预测相关系数为0.9614。模型评估的结果表明,该光谱仪能够满足油菜籽成分检测的需求,验证该光谱仪在商业领域具有重要的应用价值。

关键词：数字微镜器件近红外光谱仪阿达玛信噪比嵌入式油菜籽

Transparent h-BN/polyacrylamide nanocomposite hydrogels with enhanced mechanical properties

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2016年第9期27卷 1490-1494页

作者： zhi-Qiang Duan Ming Zhong fu-Kuan Shi Xu-Ming xie Laboratory of Advanced Materials (MOE) Department of Chemical Engineering Tsinghua University

In this study, a facile way has been proposed to prepare transparent, tough and flexible polyacrylamide （PAM） hydrogels which is composed of a dually crosslinked single network by chemical crosslinking of N,N＇-methylenebisacrylamide （BIS） and physical crosslinking of hydrophilic hexagonal boron nitride （h- BN） nanosheets. The resulting h-BN/PAM nanocomposite hydrogels are highly transparent, and exhibit significantly enhanced mechanical properties compared to the dark （GO）/PAM nanocomposite hydrogels or chemical crosslinking PAM hydrogels. Thus it opens up new opportunities for developing next- generation transparent, tough and flexible hydrogels that hold great promise in such important applications as light responsive soft robot and liquid microlenses.

关键词： Hexagonal boron nitride Polyacrylamide Nanocomposite hydrogels Mechanical properties Transparency

L^(p)-Estimate for Linear Forward-Backward Stochastic Differential Equations

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2023年第5期39卷 827-845页

作者： Bing xie zhi Yong YU School of Mathematics Shandong UniversityJinan 250100P.R.China

This paper is concerned with coupled linear forward-backward stochastic differential equations(FBSDEs,for short).When the homogeneous coefficients are deterministic(the non-homogeneous coefficients can be random),we obtain an L^(P)-result(p>2),including the existence and uniqueness of the p-th power integrable solution,a p-th power estimate,and a related continuous dependence property of the solution on the coefficients,for coupled linear FBSDEs in the monotonicity framework over large time *** order to get rid of the stubborn constraint commonly existing in the literature,i.e.,the Lipschitz constant of σ with respect to z is very small,we introduce a linear transformation to overcome the difficulty on small intervals,and then"splice"the L^(P)-results obtained on many small intervals to yield the desired one on a large interval.

关键词： Forward-backward stochastic differential equation L^(P)-estimate monotonicity condition large interval

同方期刊数据库

Effect of Deformation Temperature on Deformation Mechanism of Fe-6.5Si Alloys with Different Initial Microstructures

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2016年第4期23卷 344-349页

作者： Hua-dong fu Yuan-ke MO Long-chao ZHUO zhi-hao ZHANG Jian-xin xie Institute for Advanced Materials and Technology University of Science and Technology Beijing School of Materials Science and Engineering Xi'an University of Technology

Deformation behaviors and mechanisms under different temperatures for columnar-grained Fe 6.5Si （mass%） alloys fabricated by directional solidification and equiaxed grained Fe-6.5Si alloy fabricated by forging were comparatively investigated. The results showed that, with increasing the deformation temperature from 300℃ to 500℃, the elongation increased from 2.9% to 30.1% for the equiaxed-grained Fe-6.5Si alloy, while from 6.6% to about 51% for the columnar-grained Fe-6.5Si alloy. The deformation mode of equiaxed-grained Fe 6.5Si alloy trans ferred from nearly negligible plastic deformation to large plastic deformation dominated by dislocation slipping. Comparatively, the deformation mode of the columnar grained alloy transferred from nearly negligible plastic deformation to plastic deformation dominated by the twining, and finally to plastic deformation dominated by dislocation slipping. Meanwhile, compared with the alloy with equiaxed grains, it was found that ultimate tensile strength and elongation could be increased simultaneously, which was ascribed for the twinning deformation in columnar-grained Fe-6.5Si al loy. This work would assist us to further understand the plastic deformation mechanism of Fe-6.5Si alloy and pro vide more clues for high-efficiency production of the alloy.

关键词： Fe-6.5Si alloy deformation behavior microstructure control mechanical property tensile deformation

Effect of Warm Rolling on Micro-deformation Behavior and Mechanical Properties of Columnar-grained Fe-6.5 mass%Si Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2016年第3期23卷 225-230页

Micro-deformation behavior and mechanical properties of columnar-grained Fe-6.5 mass%Si alloy before and after warm rolling were investigated by means of micro-indentation and three-point bending *** results show that the columnar-grained Fe-6.5mass%Si alloy before warm rolling presents sink-in mode of micro-indentation,while pile-up mode with a number of arc-shaped deformation bands exists in the warm-rolled *** with that of the alloy before warm rolling,the maximum bending fracture stress and maximum bending fracture deflection of the warm-rolled alloy are increased by 96% and 50%,*** different micro-deformation behavior and mechanical properties of the columnar-grained Fe-6.5mass%Si alloy are ascribed to the changes of dislocation density,dislocation configuration and long-range order degree,which significantly improve the room temperature plasticity of the alloy after warm rolling.

关键词： Fe-6.5mass%Si alloy warm rolling micro-deformation mechanical property

Improved cold rolling workability of warm rolled Fe?6.5wt%Si electrical steel with columnar grains by annealing

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2015年第11期22卷 1171-1182页

作者： Yuan-ke Mo zhi-hao Zhang Jian-xin xie Hua-dong fu Hong-jiang Pan Institute for Advanced Materials and Technology University of Science and Technology Beijing

The effects of annealing temperature（with the annealing time being constant at 1 h） on the microstructure, ordering, residual stress, mechanical properties, and subsequent cold rolling workability of Fe-6.5wt%Si electrical steel with columnar grains were investigated, where the steel was warm rolled at 500℃ with a reduction of 95%. The results show that recrystallization began to occur in the sample annealed at 575℃ and that full recrystallization occurred in the sample annealed at 625℃. When the annealing temperature was 500℃ or greater, the extent of reordering in the sample was high, which reduced the room-temperature plasticity. However, annealing at temperatures below 300℃ did not significantly reduce the residual tensile stress on the edge of the warm rolled samples. Considering the comprehensive effects of annealing temperature on the recrystallization, reordering, residual stress, and mechanical properties of the warm rolled Fe-6.5wt%Si electrical steel with columnar grains, the appropriate annealing temperature range is 300℃-400℃. Unlike the serious edge cracks that appeared in the sample after direct cold rolling, the annealed samples could be cold rolled to a total reduction of more than 71.4% without the formation of obvious edge cracks, and bright-surface Fe-6.5wt%Si electrical steel strips with a thickness less than 0.1 mm could be fabricated by cold rolling.

关键词： electrical steel cold rolling annealing mechanical properties workability