检索结果-南通市图书馆

Thermo-kinetic characteristics on stabilizing hetero-phase interface of metal matrix composites by crystal plasticity finite element method

引用

Journal of Materials Science & Technology 2024年第2期169卷 53-67页

作者： Y.B.Zhang S.J.Song f.Liu State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Analytical&Testing Center Northwestern Polytechnical UniversityXi’an 710072China

Using dislocation-based constitutive modeling in three-dimension crystal plasticity finite element(3D CPfE)simulations,co-deformation and instability of hetero-phase interface in different material systems were herein studied for polycrystalline metal matrix composites(MMCs).Local stress and strain fields in two types of 3layer MMCs such as fcc/fcc Cu-Ag and fcc/bcc Cu-Nb have been predicted under simple compressive ***,more severe strain-induced interface instability can be observed in the fcc/bcc systems than in the fcc/fcc systems upon refining to metallic nanolayered composites(MNCs).By detailed analysis of stress and strain localization,it has been demonstrated that the interface instability is always accompanied by high-stress concentration,i.e.,thermodynamic characteristics,or high strain prevention i.e.,kinetic characteristics,at the hetero-phase *** then follows that the thermodynamic driving forceG and the kinetic energy barrier Q during dislocation and shear banding can be adopted to classify the deformation modes,following the so-called thermo-kinetic *** by inserting a high density of high-energy interfaces into the Cu-Nb composites,such thermo-kinetic integration at the hetero-phase interface allows a successful establishment of MMCs with the high△G-high Q deformation mode,which ensures high hardening and uniform strain distri-bution,thus efficiently suppressing the shear band,stabilizing the hetero-phase interface,and obtaining an exceptional combination in strength and *** hetero-phase interface chosen by a couple of thermodynamics and kinetics can be defined as breaking the thermo-kinetic correlation and has been proposed for artificially designing MNCs.

关键词： Thermodynamics and kinetics Physics-based constitutive modeling Hetero-phase interface Crystal plasticity finite element

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

On the analytical solution of transient friction in channel flows

引用

Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1447-1466页

作者： f.J.GArCíA-GArCíA P.fArINAS-ALVArINO Department of Naval&Industrial Engineering Polytechnic School of EngineeringUniversity of A CorunaCampus Industrial de FerrolFerrol 15403A CorunaSpain Integraciones Técnicas de Seguridad S.A.Pol.Ind.Espiritu SantoC/Nobel15Cambre 15650A CorunaSpain

The transient friction in channel mean flows is the sum of two contributions,i.e.,the underlying laminar flow(ULf)and the purely turbulent component(PTC),and the contributions are analyzed separately by theoretical *** is found that,the transient friction may be higher or remarkably lower than that in equal-reynolds number steady-state *** universal time constant for plane-parallel laminar flows is reported,and the role of the time constant in a turbulent mean flow is *** is shown that the time constant is related to the turbulence's frozen ***,a study of the logarithmic layer during the transient flow is accomplished,which shows that the logarithmic layer is destroyed.

关键词： transient friction transient flow unsteady channel 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

Are we ready to use new endoscopic scores for ulcerative colitis?

引用

World Journal of Gastroenterology 2024年第10期30卷 1466-1469页

作者： rodrigo Quera Paulina Núñez f Universidad de los Andes Inflammatory Bowel Disease ProgramClinica Universidad de los AndesDigestive Disease CenterSantiago 7600976RMChile Digestive Disease Center Inflammatory Bowel Disease ProgramClínica Universidad de los AndesSantiago 7620157Chile Department of Gastroenterology Universidad de Chile-Hospital San Juan de DiosSantiago 770123Chile

for ulcerative colitis(UC),the variability in inflammatory activity along the colon poses a challenge in *** focus on achieving endoscopic healing in UC is evident,where the UC Endoscopic Index of Severity and Mayo Endoscopic Subscore are commonly used for ***,these indices primarily consider the most severely affected *** et al recent study validates the Toronto Inflammatory Bowel Disease Global Endoscopic reporting(TIGEr)score offering a comprehensive assessment of inflammatory activity across diverse segments of the colon and rectum and a reliable index correlating strongly with UC Endoscopic Index of Severity and moderately with Mayo Endoscopic Subscore(MES).Despite recommendation,certain aspects warrant further *** calprotectin,an intermediate target,correlates with TIGEr and should be *** TIGEr scores defining endoscopic remission and response,evaluating agreement with histological activity,and assessing inter-endoscopist agreement for TIGEr require *** the correlation between TIGEr and intestinal ultrasound,akin to MES,adds value.

关键词： Ulcerative colitis Sigmoidoscopy Colonoscopy Score index

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

Two-Stream Approximation to the radiative Transfer Equation:A New Improvement and Comparative Accuracy with Existing Methods

引用

Advances in Atmospheric Sciences 2024年第2期41卷 278-292页

作者： f.Momo TEMGOUA L.Akana NGUIMDO DNJOMO Environmental Energy Technologies Laboratory(EETL) Faculty of SciencesUniversity of YaoundéPO Box 812 YaoundéCameroon Department of Electrical and Electronic Engineering Faculty of Engineering and TechnologyUniversity of BueaPO Box 63 BueaCameroon

Mathematical modeling of the interaction between solar radiation and the Earth's atmosphere is formalized by the radiative transfer equation(rTE), whose resolution calls for two-stream approximations among other methods. This paper proposes a new two-stream approximation of the rTE with the development of the phase function and the intensity into a third-order series of Legendre polynomials. This new approach, which adds one more term in the expression of the intensity and the phase function, allows in the conditions of a plane parallel atmosphere a new mathematical formulation of γparameters. It is then compared to the Eddington, Hemispheric Constant, Quadrature, Combined Delta function and Modified Eddington, and second-order approximation methods with reference to the Discrete Ordinate(Disort) method(δ –128 streams), considered as the most precise. This work also determines the conversion function of the proposed New Method using the fundamental definition of two-stream approximation(f-TSA) developed in a previous work. Notably,New Method has generally better precision compared to the second-order approximation and Hemispheric Constant methods. Compared to the Quadrature and Eddington methods, New Method shows very good precision for wide domains of the zenith angle μ 0, but tends to deviate from the Disort method with the zenith angle, especially for high values of optical thickness. In spite of this divergence in reflectance for high values of optical thickness, very strong correlation with the Disort method(r ≈ 1) was obtained for most cases of optical thickness in this study. An analysis of the Legendre polynomial series for simple functions shows that the high precision is due to the fact that the approximated functions ameliorate the accuracy when the order of approximation increases, although it has been proven that there is a limit order depending on the function from which the precision is lost. This observation indicates that increasing the order of app

关键词： radiative Transfer Equation two-stream method Legendre polynomial optical thickness moments of specific intensity conversion function transmittance reflectance

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

Survival and risk analysis of patients with COVID-19 in Iran

引用

Journal of Acute Disease 2024年第2期13卷 60-66页

作者： Mottaghipoor f Heidari Z Sami r Memarzadeh H Saghaeiannejad Isfahani S Department of Management and Health Information Technology Isfahan University of Medical SciencesIsfahanIran Department of Biostatistics and Epidemiology Isfahan University of Medical SciencesIsfahanIran Department of Internal Medicine School of MedicineIsfahan University of Medical SciencesIsfahanIran Software Engineering Isfahan University of Medical SciencesIsfahanIran Health Information Technology research Center Isfahan University of Medical SciencesIsfahanIran

Objective:To evaluate the risk factors of death caused by COVID-19 in ***:This study was a retrospective cohort study from february 20,2020,to August 22,2022,in the hospitals in Isfahan,*** data were collected through a researcher-made *** determine the risk factors of the death,logistic regression and Cox regression models were *** each variable,the odds ratio and 95%confidence interval were also ***:1885 Patients were *** age of deceased persons was significantly higher than that of the surviving *** risk of death for the age group above 60 years was about 14 times higher than that of people aged 19-35 years[95%CI:14.41(2.02-102.99),Prtension[95%CI:1.92(1.47-2.5),Pronic obstructive pulmonary disease[95%CI:1.92(1.47-2.50),Pre also risk factors of ***:This study reveals that the mortality rate due to COVID-19 is associated with old age,longer hospitalization in the ICU,increased length of stay,and comorbidities of high blood pressure,diabetes,and chronic pulmonary disease.

关键词： Cause Death Survival COVID-19 risk factors Iran

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

Benchmarks for Pirá2.0,a reading Comprehension Dataset about the Ocean,the Brazilian Coast,and Climate Change

引用

Data Intelligence 2024年第1期6卷 29-63页

作者： Paulo Pirozelli Marcos M.José Igor Silveira flávio Nakasato Sarajane M.Peres Anarosa A.f.Brandão Anna H.r.Costa fabio G.Cozman Universidade de São Paulo ringgold Standard Institution-Instituto de Estudos Avançados Av.370 São Paulo 05508-900Brazil Universidade de São Paulo ringgold Standard Institution-Instituto de Matemática e Estatística Av.370 São Paulo 05508-900Brazil Universidade de São Paulo Rua Cayowaá876 apto 141SÃO PAULO 05018-001Brazil Universidade de São Paulo ringgold Standard Institution Escola Politécnica Av.370São Paulo 05508-900Brazil.

Piráis a reading comprehension dataset focused on the ocean,the Brazilian coast,and climate change,built from a collection of scientific abstracts and reports on these *** dataset represents a versatile language resource,particularly useful for testing the ability of current machine learning models to acquire expert scientific *** its potential,a detailed set of baselines has not yet been developed for Pirá.By creating these baselines,researchers can more easily utilize Piráas a resource for testing machine learning models across a wide range of question answering *** this paper,we define six benchmarks over the Pirádataset,covering closed generative question answering,machine reading comprehension,information retrieval,open question answering,answer triggering,and multiple choice question *** part of this effort,we have also produced a curated version of the original dataset,where we fixed a number of grammar issues,repetitions,and other ***,the dataset has been extended in several new directions,so as to face the aforementioned benchmarks:translation of supporting texts from English into Portuguese,classification labels for answerability,automatic paraphrases of questions and answers,and multiple choice *** results described in this paper provide several points of reference for researchers interested in exploring the challenges provided by the Pirádataset.

关键词： Natural language processing Question answering Benchmarks Language resource DomainOriented dataset Scientific knowledge text dataset

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

formation of diffuse and spark discharges between two needle electrodes with the scattering of particles

引用

Plasma Science and Technology 2024年第9期26卷 32-39页

作者： Victor f TArASENKO Dmitry V BELOPLOTOV Alexei N PANCHENKO Dmitry A SOrOKIN Institute of High Current Electronics Siberian BranchRussian Academy of SciencesTomsk 634055Russia National research Tomsk State University Tomsk 634050Russia

The development of a nanosecond discharge in a pin-to-pin gap filled with air at atmospheric pressure has been studied with high temporal and spatial resolutions from a breakdown start to the spark *** and negative nanosecond voltage pulses with an amplitude of tens of kilovolts were ***-resolved images of the discharge development were taken with a fourchannel Intensified Charge Coupled Device(ICCD)*** minimum delay between the camera channels could be as short as≈0.1 *** made it possible to study the gap breakdown process with subnanosecond *** was observed that a wide-diameter streamer develops from the high-voltage pointed *** ionization processes near the grounded pin electrode started when the streamer crossed half of the *** bridging the gap by the streamer,a diffuse discharge was *** development of spark leaders from bright spots on the surface of the pointed electrodes was observed at the next *** was found that the rate of development of the spark leader is an order of magnitude lower than that of the wide-diameter *** thin luminous tracks were observed against the background of a discharge plasma *** has been established that the tracks are adjacent to brightly glowing spots on the electrodes and are associated with the flight of small particles.

关键词： needle electrodes short voltage pulses atmospheric air streamer breakdown diffuse and spark discharges scattering metal particles

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

New evidence for the epigenetic regulation of skeletal stem cells

引用

Science Bulletin 2024年第13期69卷 2004-2006页

作者： Liming Zhao Jun Xiao Charles K.f.Chan Institute for Stem Cell Biology and regenerative Medicine Stanford University School of MedicineStanford CA 94305USA Department of Surgery Division of Plastic and Reconstructive SurgeryStanford University School of MedicineStanford CA 94305USA Department of Orthopaedic Surgery Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China

Skeletal stem cells(SSCs)are crucial for skeletal development and regeneration,yet the epigenetic regulation of these cells remains poorly *** studies have delineated the epigenetic landscape across the developmental trajectory of SSCs,highlighting the involvement of Ptip in regulating SSC *** skeletal system undergoes dynamic remodeling throughout *** stem cells(SSCs),residing within the skeleton and lineage-restricted,serve as a cellular reserve to foster development and maintain skeletal *** categorized within the broader mesenchymal stromal/stem cells(MSCs).

关键词： skeletal involvement maintain

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

Sex-specific life-history trait expression in hybrids of a cave- and surface-dwelling fish (Poecilia mexicana, Poecilidae)

引用

Current Zoology 2024年第4期70卷 421-429页

作者： rüdiger riesch Luis r.Arriaga Ingo Schlupp Department of Biological Sciences Royal Holloway University of LondonEghamTW20 OEXUK CEfE CNRSUnivMontpellierEPHEIRDMontpellierFrance Department of Biology University of OklahomaNormanOK 73019USA

Evaluating the fitness of hybrids can provide important insights into genetic differences between species or diverging *** focused on surface-and cave-ecotypes of the widespread Atlantic molly Poecilia mexicana and raised f1 hybrids of reciprocal crosses to sexual maturity in a common-garden *** were reared in a fully factorial 2 x 2 design consisting of lighting(light ***)and resource availability(high *** food).We quantified survival,ability to realize their full reproductive potential(i.e.,completed maturation for males and 3 consecutive births for females)and essential life-history *** to the performance of pure cave and surface fish from a previous experiment,f1s had the highest death rate and the lowest proportion of fish that reached their full reproductive *** also uncovered an intriguing pattern of sex-specific phenotype expression,because male hybrids expressed cave molly life histories,while female hybrids expressed surface molly life *** results provide evidence for strong selection against hybrids in the cave molly system,but also sug-gest a complex pattern of sex-specific(opposing)dominance,with certain surface molly genes being dominant in female hybrids and certain cavemollygenes beingdominant in malehybrids.

关键词： dominance life-history evolution local adaptation postzygotic isolation selection against hybrids.

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

Artificial ground freezing of underground mines in cold regions using thermosyphons with air insulation

引用

International Journal of Mining Science and Technology 2024年第5期34卷 643-654页

作者： Ahmad f.Zueter Mohammad Zolfagharroshan Navid Bahrani Agus P.Sasmito Department of Civil and resource Engineering Dalhousie UniversityHalifax B3H4R2Canada Department of Mining Engineering McGill UniversityMontreal H3A0E8Canada

Current practice of underground artificial ground freezing(AGf)typically involves huge refrigeration systems of large economic and environmental *** this study,a novel AGf technique is proposed deploying available cold wind in cold *** is achieved by a static heat transfer device called thermosyphon equipped with an air insulation layer.A refrigeration unit can be optionally integrated to meet additional cooling *** introduction of air insulation isolates the thermosyphon from ground zones where freezing is not needed,resulting in:(1)steering the cooling resources(cold wind or refrigeration)towards zones of interest;and(2)minimizing refrigeration *** design is demonstrated using well-validated mathematical models from our previous work based on two-phase enthalpy method of the ground coupled with a thermal resistance network for the *** Canadian mines are considered:the Cigar Lake Mine and the Giant *** results show that our proposed design can speed the freezing time by 30%at the Giant Mine and by two months at the Cigar Lake ***,a cooling load of 2.4 GWh can be saved at the Cigar Lake ***,this study provides mining practitioners with sustainable solutions of underground AGf.

关键词： Artificial ground freezing Underground mining Sustainable mining Thermosyphon Air insulation Cold regions

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：