检索结果-南通市图书馆

Theory, simulation and experiment of optical properties of cobalt ferrite(CoFe2O4) nanoparticles

Journal of Materials science & Technology 2020年第22期54卷 180-187页

作者： Elham Gharibshahi Brandon D.Young amar s.bhalla Ruyan Guo Department of Electrical and Computer Engineering University of Texas at San Antonio.One UTSA CircleSan AntonioTX 78249USA

Optical properties of cobalt ferrite(CoFe2O4) nanoparticles are modeled and simulated employing finite element analysis(FEA) and density functional theory(DFT) for different particle sizes. The simulated absorption maxima of electronic excitations is red-shifted from 330 nm to 410 nm using finite element analysis and from 331.27 nm to 409.07 nm using quantum mechanical method, with increasing particle sizes from 40 nm to 50 nm. The measured absorption maxima matched the simulated results reasonably well and red-shifted to longer wavelengths from 315.59 nm to 426.73 nm with the increase in particle sizes from 30 nm to 50 nm. The DFT simulated, FEA simulated and experimentally derived optical band gap energies, Eg, were also acquired and compared. The simulated Egvalues decreased from 3.228 to 2.478 e V and from 3.266 to 2.456 e V, while the experimental Egvalue decreased from 3.473 to 2.697 e V, with increasing the particle sizes. The research demonstrated that the optical absorption of CoFe2O4 nanoparticles can be described with high accuracy using the quantum mechanical interpretation based on DFT. FEA based simulations have shown limitations for smaller(s likely due to the increased surface scattering that prevented a stable solution for simulations beyond the quasistatic limit. The DFT computational tool developed by this study can enable both the low cost computation and highly reliable prediction of optical absorption properties and optical band edges, and thus contribute to understanding and design of CoFe2O4 nanoparticle properties prior to fabrication and functionalization of them, for a wide range of applications especially for sensing and photonic wave modulations.

关键词： Cobalt ferrite(CoFe2O4)nanoparticles Optical properties Band gap energy DFT simulation of nanoparticles COMsOL simulation of nanoparticles

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

OPTIMAL CONTROL OF AN M/G/1 RETRIAL QUEUE WITH VACATIONs

引用

Journal of systems science and systems Engineering 2008年第4期17卷 487-502页

作者： amar AIssANI University of science & Technology Houari Boumediene BP 32 El Alia Bab-Ez-Zouar 16111Algeria

In this note, we consider an M/G/1 retrial queue with server vacations, when retrial times, service times and vacation times are arbitrary distributed. The distribution of the number of customers in the system in stationary regime is obtained in terms of generating function. Next, we give heavy traffic approximation of such distribution. We show that the system size can be decomposed into two random variables, one of which corresponds to the system size of the ordinary M/G/1 FIFO queue without vacation. such a stochastic decomposition property is useful for the computation of performance measures of interest. Finally, we solve simple problems of optimal control of vacation and retrial policies.

关键词： Retrial queues vacation optimal control stochastic decomposition ageing distribution heavy traffic

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

Finite element analysis of slope stability by expanding the mobilized principal stress Mohr's circles-Development, encoding and validation

引用

Journal of Rock Mechanics and Geotechnical Engineering 2022年第4期14卷 1165-1179页

作者： Djillali amar Bouzid Department of Civil Engineering Faculty of TechnologyUniversity of Blida 1Blida09000Algeria

In recent years,finite element analysis is increasingly being proposed in slope stability problems as a competitive method to traditional limit equilibrium methods(LEMs)which are known for their inherent ***,the application of finite element method(FEM)to slope stability as a strength reduction method(sRM)or as finite element limit analysis(FELA)is not always a success for the drawbacks that characterize both *** increase the performance of finite element analysis in this problem,a new approach is proposed in this *** consists in gradually expanding the mobilized stress Mohr’s circles until the soil failure occurs according to a prescribed non-convergence *** present approach called stress deviator increasing method(sDIM)is considered rigorous for three main ***,it preserves the definition of the factor of safety(FOs)as the ratio of soil shear strength to the mobilized shear ***,it maintains the progressive development of shear stress resulting from the increase in the principal stress deviator on the same plane,on which the shear strength takes ***,by introducing the concept of equivalent stress loading,the resulting trial stresses are checked against the violation of the actual yield criterion formed with the real strength parameters rather than those reduced by a trial *** new numerical procedure was encoded in a Fortran computer code called s^(4)DINA and verified by several *** with other numerical methods such as the sRM,gravity increasing method(GIM)or even FELA by assessing both the FOs and contours of equivalent plastic strains showed promising results.

关键词： slope stability,Finite element analysis strength reduction method(sRM),stress point-based factor of safety(FOs),Limit equilibrium method(LEM),stress deviator Mohr’s circle,Plastic strain

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 LERAY-sCHAUDER CONDITION FOR 1-sET WEAKLY-CONTRACTIVE AND(ws)-COMPACT OPERATORs

引用

Acta Mathematica scientia 2014年第2期34卷 263-273页

作者： Afif BEN amar Department of Mathematics Faculty of Sciences

Abstract The main purpose of this article is to prove a collection of new nxea point theorems for （ws）-compact and so-called 1-set weakly contractive operators under Leray- schauder boundary condition. We also introduce the concept of semi-closed operator at the origin and obtain a series of new fixed point theorems for such class of operators. As consequences, we get new fixed point existence for （ws）-compact （in particular nonexpansive） self mappings unbounded closed convex subset of Banach spaces. The main condition in our results is formulated in terms of axiomatic measures of weak noncompactness. Later on, we give an application to generalized Hammerstein type integral equations.

关键词： Measure of weak noncompactness weakly condensing and weakly nonexpan-sire (ws)-compact operator fixed point theorems semi-closed at the origin

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

Inflammatory bowel disease:Therapeutic limitations and prospective of the stem cell therapy

引用

World Journal of stem Cells 2020年第10期12卷 1050-1066页

作者： Rangnath Mishra Punita Dhawan Anand s srivastava amar B singh Institute of stem Cell Therapy and Research San DiegoCA 92122United States Department of Biochemistry and Molecular Biology University of Nebraska Medical CenterOmahaNE 68118United States Fred and Pamela Buffett Cancer Center OmahaNE 68118United States VA Nebraska-Western Iowa Health Care system OmahaNE 68118United States

Inflammatory bowel disease(IBD),consisting primarily of ulcerative colitis and Crohn’s disease,is a group of debilitating auto-immune disorders,which also increases the risk of colitis-associated ***,due to the chronic nature of the disease and inconsistent treatment outcomes of current anti-IBD drugs(e.g.,approximately 30%non-responders to anti-TNFαagents),and related serious side effects,about half of all IBD patients(in millions)turn to alternative treatment *** this regard,mucosal healing is gaining acceptance as a measure of disease activity in IBD patients as recent studies have correlated the success of mucosal healing with improved ***,despite the increasing clinical realization of the significance of the concept of mucosal healing,its regulation and means of therapeutic targeting remain largely ***,stemcell therapy,which uses hematopoietic stem cells or mesenchymal stem cells,remains a promising *** cells are the pluripotent cells with ability to differentiate into the epithelial and/or immune-modulatory *** overreaching concept is that the stem cells can migrate to the damaged areas of the intestine to provide curative help in the mucosal healing ***,by differentiating into the mature intestinal epithelial cells,the stem cells also help in restoring the barrier integrity of the intestinal lining and hence prevent the immunomodulatory induction,the root cause of the *** this article,we elaborate upon the current status of the clinical management of IBD and potential role of the stem cell therapy in improving IBD therapy and patient’s quality of life.

关键词： Crohn′s disease Ulcerative colitis Mesenchymal stem cells Hematopoietic stem cells Mucosal healing

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

CT patterns of nodal disease in pediatric chest tuberculosis

引用

World Journal of Radiology 2011年第1期3卷 17-23页

作者： amar Mukund Rashmi Khurana Ashu s.bhalla Arun K Gupta sushil K Kabra Department of Radiology All India Institute of Medical SciencesNew Delhi 110029India Department of Pediatrics All India Institute of Medical SciencesNew Delhi 110029India

AIM:To highlight various patterns of nodal involvement and post treatment changes in pediatric chest tuberculosis based on contrast enhanced computed tomography(CECT) scans of ***:This was a retrospective study consisting of 91 patients aged less than 17 years,who attended Paediatrics OPD of All India Institute of Medical sciences with clinically diagnosed tuberculosis or with chest radiographs suggestive of chest *** patients had an initial chest radiograph as well as CECT of the chest and follow up imaging after 6 mo,and in some cases 9 mo,of completion of anti-tubercular treatment(ATT).CECT of these patients was reviewed for the location and extent of nodal involvement along with determination of site,size,enhancement pattern and ***:Enlargement of mediastinal or hilar lymph nodes was found in 88/91 patients(96.7%),with the most common locations being paratracheal(84.1%),and subcarinal(76.1%).The most common pattern of enhancement was found to be *** nodes were conglomerate in 56.8% and discrete in 43.2%.In addition,perinodal fat was obscured in 84.1% of *** the post-treatment scan,there was 87.4% reduction in the size of the *** nodes post-treatment were discrete and homogenous with perinodal fat *** was found both pre-and post-treatment,but there was an increase in incidence after treatment(41.7%).There was hence a reduction in size,change in enhancement pattern,and appearance of perinodal fat with ***:Tubercular nodes have varied appearance and enhancement *** and obscuration of perinodal fat suggest *** residual nodes decision to continue ATT requires clinical correlation.

关键词： Tuberculosis Lymph nodes Contrast enhanced computed tomography

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

Continuous B scan ultrasound guided post-traumatic sub-periosteal orbital hematoma drainage: An advantage over routine needle drainage procedure

引用

World Journal of Emergency Medicine 2019年第4期10卷 248-250页

作者： amar Pujari Pallavi singh Ayushi sinha shreya Nayak MANDeep s.Bajaj Rajendra Prasad Centre for Ophthalmic sciences All India Institute of Medical Sciences

Dear editor,Traumatic orbital haemorrhage is an unfortunate complication with potential vision-threatening consequences.[1-3]The collection of blood can occur anywhere along the potential free orbital spaces,[4]but the subperiosteal collection of the blood is an important clinical variant where careful and timely intervention can give commendable rewards to the surgeon as well as to the patient.[1,2]subperiosteal hematoma could be traumatic or non-traumatic,in turns,the non-traumatic cases may be due to bleeding tendency as in cases of leukaemia.

关键词： Traumatic orbital haemorrhage unfortunate complication consequences

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

Imaging panorama in postoperative complications after liver transplantation

引用

Gastroenterology Report 2016年第2期4卷 96-106,I0001页

作者： Binit sureka Kalpana Bansal s Rajesh amar Mukund Viniyendra Pamecha Ankur Arora Department of Radiology/Interventional Radiology Institute of Liver and Biliary SciencesVasant KunjNew DelhiIndia Department of Hepatobiliary surgery Institute of Liver and Biliary SciencesVasant KunjNew DelhiIndia

The liver is the second most-often transplanted solid organ after the kidney,so it is clear that liver disease is a common and serious problem around the *** the advancements in surgical,oncological and imaging techniques,orthotopic liver transplantation has become the first-line treatment for many patients with end-stage liver ***,and Doppler are the most economical and cost-effective imaging modalities for evaluating postoperative fluid collections and vascular *** tomography(CT)is used to confirm the findings of ultrasound and look for pulmonary *** resonance imaging(MRI)is used for the diagnosis of biliary complications,bile leaks and neurological *** article illustrates the imaging options for diagnosing the various complications that can be encountered in the postoperative period after liver transplantation.

关键词： liver transplant postoperative complications imaging

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

Effect of natural pozzolan content on the properties o engineered cementitious composites as repair material

引用

Frontiers of structural and Civil Engineering 2018年第3期12卷 261-269页

作者： said CHOUCHA amar BENYAHIA Mohamed GHRICI Mohamed said MANsOUR Geomaterials Laboratory Civil Engineering Department University Hassiba Benbouali of Chlef BP 151 Chief02000 Algeria

In order to determine the effect of Natural Pozzolan （NP） content on the mechanical properties and durability characteristics on Engineered Cementitious Composites （ECC） as repair material. This study focused on the evaluation of the most factors influencing compatibility between the repair material and the base concrete including mechanicals properties such as, compressive and flexural strengths, elastic modulus, capillary absorption and drying shrinkage. The experimental results showed that natural pozzolan reduces the compressive strength and the flexuraI strength of ECC at all ages. The elastic modulus of ECC was remarkably lower than that of normal-strength concrete. This lower ~oung＇s modulus is desirable for repair concrete, because it prevents the stresses induced by restrained shrinkage. In addition, the incorporation of high-volume natural pozzolan decreases significantly the coefficient of capillary absorption at long term and increases the drying shrinkage. Generally, based on the results obtained in the present experimental investigation, ECC can be used effectively as an overlay material over existing parent concrete.

关键词： natural pozzolan engineered cementitious composites mechanical strengths elastic modulus capillary absorption drying shrinkage

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

Removal of Ni(Ⅱ)ions from wastewater by micellar enhanced ultrafiltration using mixed surfactants

引用

Frontiers of Chemical science and Engineering 2014年第1期8卷 79-86页

作者： amar D.Vibhandik Kumudini V.Marathe Department of Chemical Engineering Institute of Chemical Technology Mumbai

Ni(Ⅱ) ions were removed from aqueous waste using micellar enhanced ultrafiltration(MEUF) with a mixture of *** surfactant mixture was the nonionic surfactant Tween 80(TW80) mixed with the anionic surfactant sodium dodecyl sulfate(sDs) in different molar ratios ranging from 0.1–*** operational variables of the MEUF process such as pH,applied pressure,surfactant to metal ion ratio and nonionic to ionic surfactant molar ratio(α) were *** of Ni and TW80 was 99% and 98% respectively whereas that for sDs was 65%.The flux and all resistances(fouling resistance,resistance due to concentration polarization)were measured and calculated for entire range of αrespectively.A calculated flux was found to be declined with time,which was mainly attributed to concentration polarization rather than resistance from membrane fouling.

关键词： MEUF Ni (II) ions membrane resistance concentration polarization mixed surfactants

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

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：