检索结果-南通市图书馆

The influence of tree transmissivity variations in winter on satellite snow parameter observations

International Journal of digital Earth 2021年第10期14卷 1337-1353页

作者： Qinghuan Li Richard Kelly Juha Lemmetyinen Roger d.de Roo Jinmei Pan Yubao Qiu Geography and Environmental Management University of WaterlooWaterlooCanada Aerospace Information Research Institute Chinese Academy of SciencesBeijingPeople’s Republic of China Finnish Meteorological Institute HelsinkiFinland Climate and Space Sciences and Engineering University of MichiganAnn ArborMIUSA

The ability to correct for the influence of forest cover is crucial for retrieval of surface geophysical parameters such as snow cover and soil properties from microwave remote *** correction approaches to brightness temperatures for northern boreal forest regions consider forest transmissivity constant during ***,due to biophysical protection mechanisms,below freezing air temperatures freeze the water content of northern tree species only *** a consequence,the permittivity of many northern tree species decreases with the decrease of air temperature under sub-zero temperature *** results in a monotonic increase of the tree vegetation transmissivity,as the permittivity contrast to the surrounding air *** influence of this tree temperature-transmissivity relationship on the performance of the frequency difference passive microwave snow retrieval algorithms has not been *** ground-based observations and an analytical model simulation based on Mätzler’s approach(1994),the influence of the temperaturetransmissivity relationship on the snow retrieval algorithms,based on the spectral difference of two microwave channels,is characterized.A simple approximation approach is then developed to successfully characterize this influence(the RMSE between the analytical model simulation and the approximation approach estimation is below 0.3 K).The approximation is applied to spaceborne observations,and demonstrates the capacity to reduce the influence of the forest temperature-transmissivity relationship on passive microwave frequency difference brightness temperature.

关键词： Passive microwave snow forest

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

Mixed-species aggregations in arthropods

引用

Insect Science 2019年第1期26卷 2-19页

作者： Julien Boulay Cindy Aubernon Graeme d.Ruxton Valery Hedouin Jean-Louis deneubourg damien Charabidze CHU Lille Universite Lille 2EA 7367-UTML-Unite de Taphonomie Medico-LegaleLilleFrance School of Biology University of St. AndrewsDyers Brae HouseSt.AndrewsFifeUK Unit of Social Ecology-CP 231 Universite Libre de Bruxelles (ULB)Campus de la PlaineBoulevard du TriompheBrusselsBelgium

This review offers the first synthesis of the research on mixed-species groupings of arthropods and highlights the behavioral and evolutionary questions raised by such ***-species groups are commonly found in mammals and *** groups are also observed in a large range of arthropod taxa independent of their level of sociality. Several examples are presented to highlight the mechanisms underlying such groupings, particularly the evidence for phylogenetie proximity between members that promotes cross-species *** advantages offered by such aggregates are described and *** advantages can be attributed to the increase in group size and could be identical to those of nonmixed groupings,but competition-cooperation dynamics might also be involved,and such effects may differ between homo-and heterospecific *** discuss three extreme cases of interspecific recognition that are likely involved in mixed-species groups as vectors for cross-species aggregation:tolerance behavior between two social species,one-way mechanism in which one species is attractive to others and two-way mechanism of mutual *** shown in this review,the study of mixed-species groups offers biologists an interesting way to explore the frontiers of cooperation-competition, including the process of sympatric speciation.

关键词： collective behavior complex system cross-species recognition self-organization sociality

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 Tempcore Processing on Mitigating Problems of Tramp Elements in Low C Steel Produced from Recycled Material

引用

Journal of Iron and Steel Research(International) 2015年第7期22卷 582-589页

作者： Ahmed RAMAdAN A.Y.SHASH I.S.EL-MAHALLAWI d.SENK Taha MATTAR Quality department Faculty of Engineering Cairo University Institute of Ferrous Metallurgy RWTH-Aachen University Central Metallurgical Research and development Institute

The effect of tramp elements in the steel was intensively studied. It was found that the solubility of tramp elements decreased as the temperature decreased under normal cooling conditions. The tramp elements （Cu, Pb, and Sn） diffused toward the grain boundaries, and intermetallic compounds or rich phases which have low melting points were formed, causing reduction in ductility and failure during the bending test. Rebars with Cu content which were left to air cooling after the last step showed drop in elongation, up to 32 %. On contrast, the samples with high per- centage of tramp elements （Cu, Pb, and Sn） in the billet, which were rolled and subjected to Tempcore process, did not show drop in elongation or failure in bending test （especially for rebar with diameter less than 32 mm）; however, copper must be less than 0.35 mass% to prevent the precipitation of Cu-rich zones of critical size in 32 mm. When quench- ing was applied, the tramp elements remained in the interstitial supersaturated solid solution positions inside the grains and would not have the chance to diffuse and form precipitates, hindering the copper precipitates from reac- hing the critical size necessary for impairing the properties. This would hinder the occurrence of the harmful effect of the tramp elements on the elongation or the hot shortness after rolling.

关键词： recycled steel hot shortness crack susceptibility Tempcore process tramp element residual melt

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

NUMERICAL ANALYSIS OF HEAT TRANSFER dURING LASER CLAddING TO SYNTHESIZE TiCp/Al COMPOSITE

引用

Acta Metallurgica Sinica(English Letters) 2004年第1期17卷 1-6页

作者： d.N.Zou J.Yang Y.L.Huang J.Y.Su School of Metallurgical Engineering Xi'an University of Architecture and Technology Xi'an 710055ChinaSchool of Metallurgical EngineeringXi'an University of Architecture and Technology Xi'an 710055ChinaSchool of Materials Science and Engineering Xi'an Jiaotong University Xi'an 710049 ChinaSchool of Materials Science and Engineering Xi'an Jiaotong University Xi'an 710049 China

Based on the continuum model for binary solid-liquid phase change system, the math-ematic model to simulate the process of laser cladding in situ synthesis TiCp/Al composite on the surface of aluminum alloy was formulated. The additive source method was employed to treat with the heat release of synthetic reaction in powder mixture at certain temperatures, and also to solve the momentum and heat transfer caused by the relative movement between laser beam and the specimen. Two different types of driving forces for flow were considered in the model, i.e., the buoyancy force and the surface tension gradient at the laser pool surface. The three-dimensional transient temperature field simulation program was developed being based upon the commercial software PHOENICS. The calculated and observed fusion boundaries were compared and very good agreement was obtained.

关键词： numerical simulation heat transfer laser cladding in situ synthesis composite

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

MICROSTRVCTURE SIMULATION ANd PROCESS OPTIMIZATION OF TURBINE BLAdE CASTINGS

引用

Acta Metallurgica Sinica(English Letters) 1998年第5期11卷 383-390页

作者： d.Z.Li Z.Y.Hu Q.Li Y.Y.Li Inst of Metal Research The Chinese Acad of Sciences Shenyang China

The probabilistic modeling is applied to calculate microstructural features of the thin complex smprolloy turbine blades cast by the vacuum investment process. The random distribution, orientation and physical mechanism of the nucleation, the growth kinetics of dendrites and the columnar-to-equiaxed transition (CET) are *** on these simulating schemes, the comprehensive influence of key process variables on the scale and uniformity of grains has been involved quantitatively. The validity of the modeling is confirmed by selection of the optimum process variables.

关键词： Probabilistic modeling microstructure process optimization

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

What we should know about portal vein thrombosis in cirrhotic patients:A changing perspective

引用

World Journal of Gastroenterology 2012年第36期18卷 5014-5020页

作者： Francesca Romana Ponziani Maria Assunta Zocco Matteo Garcovich Francesca d'Aversa davide Roccarina Antonio Gasbarrini Internal Medicine and Gastroenterology Policlinico A.GemelliCatholic University of Romelargo A.Gemelli800168 RomeItaly

Portal vein thrombosis(PVT) is one of the most common complications occurring during the natural course of liver *** though PVT is often asymptomatic,the worsening of liver function,an unexpected episode of gastrointestinal bleeding or ascitic decompensation may be landmarks of PVT *** these clinical manifestations,it is debated whether PVT really has an impact on liver cirrhosis natural history or rather represents only one of its *** PVT development should not only be considered as a matter of impaired blood flow or pro-coagulation *** one hand,PVT seems a consequence of the worsening in portal vein outflow due to the increased hepatic resistance in cirrhotic *** the other hand,vascular microthrombosis secondary to necroinflammation may cause liver ischemia and infarction,with loss of hepatic tissue(parenchymal extinction) which is replaced by fibrotic ***,PVT might also be considered as the overt manifestation of the liver fibrosing process evolution and anticoagulant therapy may thus have microscopic indirect effects also on the progression of liver *** present,a connection between PVT development and the progression of liver fibrosis/cirrhosis has not yet been ***,it is not clear if PVT development may worsen cirrhotic patients' outcome by *** authors tried to assess liver transplant benefit in PVT cirrhotic patients but data are *** this review,we will try to answer these questions,providing a critical analysis of data reported in literature.

关键词：血栓形成肝硬化门静脉患者肝纤维化 PVT 抗凝血剂标志性建筑

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

Secure data networks for electrical distribution applications

引用

Journal of Modern Power Systems and Clean Energy 2015年第3期3卷 447-455页

作者： david M.LAVERTY John B.O’RAW Kang LI d.John MORROW School of EEECS Queen’s University Belfast125 Stransmillis RoadBelfast BT95AHUK

Smart Grids are characterized by the application of information communication technology(ICT)to solve electrical energy *** power networks span large geographical areas,thus a necessary component of many Smart Grid applications is a wide area network(WAN).For the Smart Grid to be successful,utilities must be confident that the communications infrastructure is *** paper describes how a WAN can be deployed using WiMAX radio technology to provide high bandwidth communications to areas not commonly served by utility communications,such as generators embedded in the distribution network.A planning exercise is described,using Northern Ireland as a case *** suitability of the technology for real-time applications is assessed using experimentally obtained latency data.

关键词： Telecoms Latency WiMAX Security

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

Cytokines from the pig conceptus:roles in conceptus development in pigs

引用

Journal of Animal Science and Biotechnology 2015年第2期6卷 130-141页

作者： Rodney d Geisert Matthew C Lucy Jeffrey J Whyte Jason W Ross daniel J Mathew Animal Sciences Research Center University of Missouri department of Animal Science Iowa State University

Establishment of pregnancy in pigs involves maintaining progesterone secretion from the corpora lutea in addition to regulating a sensitive interplay between the maternal immune system and attachment of the rapidly expanding trophoblast for nutrient absorption. The peri-implantation period of rapid trophoblastic elongation followed by attachment to the maternal uterine endometrium is critical for establishing a sufficient placental-uterine interface for subsequent nutrient transport for fetal survival to term, but is also marked by the required conceptus release of factors involved with stimulating uterine secretion of histotroph and modulation of the maternal immune system. Many endometrial genes activated by the conceptus secretory factors stimulate a tightly controlled proinflammatory response within the uterus. A number of the cytokines released by the elongating conceptuses stimulate inducible transcription factors such as nuclear factor kappa B （NFKB） potentially regulating the maternal uterine proinflammatory and immune response. This review will establish the current knowledge for the role of conceptus cytokine production and release in early development and establishment of pregnancy in the pig.

关键词： Cytokines Embryo development Porcine conceptus Pregnancy Prostaglandins uterus

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

Stress and immunological response of heifers divergently ranked for residual feed intake following an adrenocorticotropic hormone challenge

引用

Journal of Animal Science and Biotechnology 2018年第1期9卷 111-118页

作者： A.K.Kelly P.Lawrence B.Earley d.A.Kenny M.McGee School of Agriculture and Food Science College of Health and Agricultural SciencesUniversity College Dublin Livestock Systems Research department Teagasc Animal&Grassland Research and Innovation CentreGrangeDunsanyCo. Animal and Bioscience Research department Animal&Grassland Research and Innovation CentreTeagascDunsanyCo.

Background： When an animal is exposed to a stressor, metabolic rate, energy consumption and utilisation increase primarily through activation of the hypothalamic-pituitary-adrenal（HPA） axis. Changes to partitioning of energy by an animal are likely to influence the efficiency with which it is utilised. Therefore, this study aimed to determine the physiological stress response to an exogenous adrenocorticotropic hormone（ACTH） challenge in beef heifers divergently ranked on phenotypic residual feed intake（RFI）.Results： data were collected on 34 Simmental weaning beef heifers the progeny of a well characterized and divergently bred RFI suckler beef herd. Residual feed intake was determined on each animal during the postweaning stage over a 91-day feed intake measurement period during which they were individually offered adlibitum grass silage and 2 kg of concentrate per head once daily. The 12 highest [0.34 kg dM/d] and 12 lowest[-0.48 kg dM/d] ranking animals on RFI were selected for use in this study. For the physiological stress challenge heifers（mean age 605 ± 13 d; mean BW 518 ± 31.4 kg） were fitted aseptically with indwelling jugular catheters to facilitate intensive blood collection. The response of the adrenal cortex to a standardised dose of ACTH（1.98 IU/kg metabolic BW^（0.75）） was examined. Serial blood samples were analysed for plasma cortisol, ACTH and haematology variables. Heifers differing in RFI did not differ（P = 0.59） in ACTH concentrations. Concentration of ACTH peaked（P 〈 0.001） in both RFI groups at 20 min post-ACTH administration, following which concentration declined to baseline levels by 150 min. Similarly, cortisol systemic profile peaked at 60 min and concentrations remained continuously elevated for 150 min. A RFI × time interaction was detected for cortisol concentrations（P = 0.06） with high RFI heifers had a greater cortisol response than Low RFI from 40 min to 150 min relative to ACTH administration. Cortisol response was positively assoc

关键词： Beef cattle Cortisol Feed efficiency Residual feed intake Stress response

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

Towards creep property improvement of selective laser melted Ni-based superalloy IN738LC

引用

Journal of Materials Science & Technology 2022年第17期112卷 301-314页

作者： H.Y.Song M.C.Lam Y.Chen S.Wu P.d.Hodgson X.H.Wu Y.M.Zhu A.J.Huang Monash Centre for Additive Manufacturing 15-17 Normanby RdNotting HillVIC 3168Australia department for of Materials Science and Engineering Monash UniversityClaytonVIC 3800Australia Monash Centre for Electron Microscopy 10 Innovation WalkClaytonVIC 3800Australia Institute for Frontier Materials Deakin UniversityVIC 3216Australia

Nickel-based superalloy IN738LC produced by selective laser melting(SLM)exhibits inferior hightemperature creep properties than its cast counterparts due to relatively smaller grain size,particularly for the plane normal to the building *** work studied effects of post heating strategy on the microstructure and especially the grain size to improve the high temperature creep *** asbuilt microstructure exhibited a fine grain size and large quantities of MC carbides that could effectively hinder grain *** was found that unconventional two-step heat treatments could lead to substantial grain growth,and the effect is particularly prominent at a specific *** ease of grain growth was explained after classifying the microstructural evolution(boundary carbide transformation)during each heating step and related to the reduced grain boundary pinning force from MC *** tests validated the effect of the new heat treatment scheme on the SLM-processed IN738LC at 850℃.An extended creep fracture life(1.5 to 4 times improvement)and lower secondary creep rates were achieved with samples subjected to the newly optimized two-step heat *** complete creep curves are also firstly presented for SLM-IN738LC,confirming the effectiveness of grain growth and highlighting the importance of dedicated heat treatment for SLM superalloys.

关键词： Selective laser melting IN738LC alloy Creep properties Heat treatments Grain structure

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：