检索结果-南通市图书馆

Modelling ballistic impact on military helmets:The relevance of projectile plasticity

Defence Technology（防务技术） 2021年第5期17卷 1699-1711页

作者： A.Caçoilo R.Mourao f.Teixeira-Dias A.Azevedo f.Coghe R.A.f.Valente School of Engineering The University of EdinburghEdinburghEH93FGUK Dept.Weapon Systems and Ballistics Royal Military AcademyBrusselsBelgium Centre for Mechanical Technology and Automation Department of Mechanical EngineeringUniversity of AveiroPortugal

The need to develop armour systems to protect against attacks from various sources is increasingly a matter of personal,social and national *** develop innovative armour systems it is necessary to monitor developments being made on the type,technology and performance of the threats(weapons,projectiles,explosives,etc.) Specifically,the use of high protection level helmets on the battlefield is *** development of evaluation methods that can predict injuries and trauma is therefore of major ***,the risk of injuries or trauma that can arise from induced accelerations is an additional *** develop new materials and layouts for helmets it is necessary to study the effects caused by ballistic impacts in the human head on various *** use of numerical simulation is a fundamental tool in this *** work here presented focuses on the use of numerical simulation(finite elements analysis) to predict the consequences of bullet impacts on military helmets on human *** main objectives are to assess the level and probability of head trauma using the Head Injury Criterion,caused by the impact of a 9 mm NATO projectile on a PASGT helmet and to quantify the relevance of projectile plasticity on the whole modelling *** accelerations derived from the impact phenomenon and the deformations caused on the helmet are evaluated using fully three-dimensional models of the helmet,head,neck and *** studies are done at impact angles ranging from 0 to 75°.Results are presented and discussed in terms of HIC and probability of acceleration induced trauma *** comparison analyses are done using a rigid and a deformable projectile and it is observed that plastic deformation of the projectile is a significant energy dissipation mechanism in the whole impact process.

关键词： Ballistic impact Helmet impact Plasticity finite element analysis Injury Trauma HIC

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The theoretical study of the efficiency of diffusion deposition of nanoaerosols in the extended range of the Peclet numbers

引用

Particuology 2023年第6期77卷 47-55页

作者： R.f.Mardanov S.K.Zaripov V.f.Sharafutdinov N.I.Lobachevskii Institute of Mathematics and Mechanics Kazan(Volga Region)Federal UniversityKremlevskaya ul.18KazanTatarstan420008Russia

The efficiencies of the diffusion deposition of nanoaerosols for a single fiber for the models of aerosol filter and wire mesh screen are studied numerically in the extended range of the Peclet number *** rectangular periodic cell model for fluid flow and convective-diffusive transport of small aerosol particles is *** of the previous theoretical and experimental studies of single fiber diffusion deposition efficiency were for the case of Pe>*** array with uniform square or chess grid of fibers and of a row of circular cylindrical fibers are considered as the filter and wire mesh screen *** flow and particles transport equations are solved numerically using the Boundary Element *** obtained numerical data are used to derive the approximate formulas for the deposition efficiency in the entire range of the Peclet number for the various porosities of the filter medium or distances between fibers in a wire mesh *** derived dependencies take into account nonlinearity of the deposition efficiency at the low Peclet *** obtained analytical dependencies compare well with the numerical and experimental data.

关键词： Arrayof fibers Row of fibers Periodic cell model Convection-diffusion equation Single fiber efficiency

来源：

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

Charge susceptibilities of armchair graphene nanoribbon in the presence of magnetic field

引用

Chinese Physics B 2016年第9期25卷 511-517页

作者： H Rezania f Azizi Department of Physics Razi University

We present the behaviors of both dynamical and static charge susceptibilities of undoped armchair graphene nanoribbon using the Green＇s function approach in the context of tight binding model ***,the effects of magnetic field on the the plasmon modes of armchair graphene nanoribbon are investigated via calculating the correlation function of charge density *** results show that the increase of magnetic field makes the high-frequency plasmon mode for both metallic and insulating cases *** also show that low-frequency plasmon mode for metallic nanoribbon appears due to increase of magnetic ***,the number of collective excitation modes increases with ribbon width at zero magnetic ***,the temperature dependence of the static charge structure factor of armchair graphene nanoribbon is *** effects of both magnetic field and ribbon width on the static charge structure factor are discussed in detail.

关键词： armchair graphene nanoribbon Green's function

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A Label-free Detection of Biomolecules Using Micromechanical Biosensors

引用

Chinese Physics Letters 2013年第6期30卷 228-231页

作者： Meisam Omidi M.A.Malakoutian Mohammadmehdi Choolaei f.Oroojalian f.Haghiralsadat f.Yazdian faculty of New Science and Technology University of TehranTehranIran Department of Electrical and Computer Engineering University of TehranTehranIran Department of Chemical Engineering South Tehran BranchIslamic Azad UniversityTehranIran

A Microcantilevers resonator is used to detect a protein biomarker called prostate specific antigen(PSA),which is associated with prostate *** concentrations of PSA in a buffer solution are detected as a function of deflection of the *** this purpose,we use a surface micromachined,antibody-coated polycrystalline silicon micromechanical cantilever *** have mass sensitivities of the order of 10–17 g/Hz,which result from their small *** matter allows them to detect an immobilized antibody monolayer corresponding to a mass of about 70 *** these devices,concentrations as low as 150 fg/mL,or 4.5 fM,could be detected from the realistic samples.

关键词： cantilever resonator polycrystalline

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Do Child–Turcotte–Pugh and nutritional assessments predict survival in cirrhosis: A longitudinal study

引用

World Journal of Hepatology 2025年第1期17卷 29-40页

作者： Randhall B Carteri Claudio A Marroni Luis f ferreira Letícia P Pinto Juliana Czermainski Cristiane V Tovo Sabrina A fernandes Department of Nutrition Centro Universitário CESUCACachoeirinha 94935-630Brazil Postgraduate in Hepatology Universidade Federal de Ciências da Saúde de Porto AlegrePorto Alegre 90050-170Brazil School of Electronics Electrical Engineering and Computer ScienceQueen’s University BelfastBelfast BT95BNNorthern IrelandUnited Kingdom

BACKGROUND Cirrhotic patients face heightened energy demands,leading to rapid glycogen depletion,protein degradation,oxidative stress,and inflammation,which drive disease progression and *** disruptions cause cellular damage and parenchymal changes,resulting in vascular alterations,portal hypertension,and liver dysfunction,significantly affecting patient *** To analyze the association between Child–Turcotte–Pugh(CTP)scores and di-fferent nutritional indicators with survival in a 15-year follow-up *** This was a retrospective cohort study with 129 cirrhotic patients of both sexes aged>18 *** of cirrhosis was made by liver *** first year of data collection was 2007,and data regarding outcomes were collected in *** were gathered from medical records,and grouped by different methods,including CTP,handgrip strength,and triceps skinfold *** prognostic values for mortality were assessed using Kaplan–Meier curves and multivariate binary logistic regression *** The coefficient for CTP was the only statistically significant variable(Wald=5.193,P=0.023).This suggests that with a negative change in CTP classification score,the odds of survival decrease 52.6%.The other evaluated variables did not significantly predict survival outcomes in the ***–Meier survival curves also indicated that CTP classification was the only significant *** Although different classifications showed specific differences in stratification,only CTP showed significant predictive *** score remains a simple and effective predictive tool for cirrhotic patients even after longer follow-up.

关键词： Liver cirrhosis Child–Turcotte–Pugh Prognosis Liver transplantation Nutritional assessment

来源：

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

Anosov and expanding attractors

引用

Science China Mathematics 2020年第9期63卷 1929-1934页

作者： Robert f.Williams Department of Mathematics University of Texas at AustinAustinTX 78705USA Institute for Advanced Study PrincetonNJ 08540USA

An earlier conjecture is settled with an immersion of a 2-dimensional branched *** obstructions in linear algebra and tiling theory are studied rst.

关键词： Anosov expanding attractor Cantor set ber bundle

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A review of landscape ecology experiments to understand ecological processes

引用

Ecological Processes 2022年第1期11卷 802-811页

作者： Yolanda f.Wiersma Department of Biology Memorial UniversitySt.John’sNL A1C 5S7Canada

Background:One way in which we make inferences about ecological processes is via *** ecological processes happen at landscape extents and it is at this extent that experimentation is more *** review explores the intersection between experimentation,ecological processes and landscape ***,this review seeks to discover how scientists design experiments to understand ecological processes at landscape ***:I found 87 papers where these three concepts intersected,and reviewed them in more depth to assess characteristics of scale(treatment and study area extent),replication,research question and experiment ***:The findings suggest that experimental approaches for understanding ecological processes are well established,and beginning to more readily accommodate spatial ***,there is room to integrate more spatially explicit,landscape-scale experiments into studies of ecological processes.

关键词： Inference Landscape ecology Manipulative experiment Observational experiment Scale

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Photometric Investigation of Contact Binary DY Cet Based on TESS Data

引用

Research in Astronomy and Astrophysics 2022年第5期22卷 121-128页

作者： M.f.Yildirim Canakkale Onsekiz Mart University Astrophysics Research Center and Ulupinar Observatory17020CanakkaleTurkey Canakkale Onsekiz Mart University Department of Electricity and EnergyCan Vocational School17400CanakkaleTurkey

We present a photometric analysis of the Transiting Exoplanet Survey Satellite(TESS)light curve of contact binary system DY Cet and the behavior of its orbital period *** light curve and published radial velocity data analysis was performed using the Wilson-Devinney *** a result of simultaneous analysis of the light curve with radial velocity data,the masses and radii of the system’s components were determined as M_(1)=1.55±0.02 M_(⊙),M_(2)=0.55±0.01 M_(⊙) and R_(1)=1.51±0.02 R_(⊙),R_(2)=0.95±0.02 R_(⊙),*** degree of contact(f)and mass ratio(q)of the system were determined as 23%and 0.355±0.012,*** period analysis of DY Cet was conducted for the first time in this *** was observed that the orbital period has a sinusoidal change with decreasing *** explain the orbital period change,mass transfer between components is proposed with the assumption of conservative mass,and the transfer rate was calculated to be dM/dt=1.1×10^(-7) M_(⊙)yr^(-1).A possible third component is suggested for explaining the sinusoidal change,and the mass of the unseen component was determined as 0.13 M_(⊙).The age of the DY Cet system was estimated as 3.77 Gyr.

关键词： stars eclipsing binary stars-stars fundamental parameters of stars- stars individual (DY Cet)

来源：

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

MHD Equilibrium with Reversed Current Density and Magnetic Islands Revisited:the Vacuum Vector Potential Calculus

引用

Plasma Science and Technology 2013年第10期15卷 985-988页

作者： f.L.BRAGA Gleb-Wataghin Physics Institute Applied Physics DepartmentState University of Campinas federal Institute of Science and Technology of Espirito Santo

The solution of Grad-Shafranov equation determines the stationary behavior of fusion plasma inside a tokamak. To solve the equation it is necessary to know the toroidal current density profile. Recent works show that it is possible to determine a magnetohydrodynamic （MHD） equilibrium with reversed current density （RCD） profiles that presents magnetic islands. In this work we show analytical MHD equilibrium with a RCD profile and analyze the structure of the vacuum vector potential associated with these equilibria using the virtual casing principle.

关键词： magnetohydrodynamics vacuum vector potential reversed current density magnetic islands

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nanoscale displacement of the image of an atomic source of radiation

引用

Chinese Optics Letters 2009年第2期7卷 149-151页

作者： Henk f. Arnoldus Department of Physics and Astronomy Mississippi State University

Light emitted by an atomic source of radiation appears to travel along a straight line （ray） from the location of the source to the observer in the far field. However, when the energy flow pattern of the radiation is resolved with an accuracy better than an optical wavelength, it turns out that the field lines are usually curved. We consider electric dipole radiation, a prime example of which is the radiation emitted by an atom during an electronic transition, and we show that the field lines of energy flow are in general curves. Near the location of the dipole, the field lines exhibit a vortex structure, and in the far field they approach a straight line. The spatial extension of the vortex in the optical near field is of nanoscale dimension. Due to the rotation of the field lines near the source, the asymptotic limit of a field line is not exactly in the radially outward direction and as a consequence, the image in the far field is slightly shifted. This sub-wavelength displacement of the image of the source should be amenable to experimental observation with contemporary nanoscale-precision techniques.

关键词： Atoms Electric dipole moments flow patterns Nanotechnology Vortex flow

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：