检索结果-南通市图书馆

Evolution of Morphology and Structure During crystallization and Melting in Syndiotactic Polypropylene

应用化学 2001年第5期18卷 280-288页

作者： Zhi-Gang WANG Benjamin S.HSIAO charles c.HAN State University of New York at Stony Brook Department of ChemistryStony BrookNY 11794-3400 Polymers Division and center for Neutron Research National Institute of Standards and TechnologyGaithersburgMD 20899

Structure and morphology development during isothermal crystallization and subsequent melting of syndiotactic polypropylene(sPP) was studied by time-resolved simultaneous small-angle X-ray scattering(SAXS) and wide-angle X-ray diffraction(WAXD) methods with synchrotron radiation and differential scanning calorimetry(DSc). The time and temperature dependent parameters such as long period, L , crystal lamellar thickness, l c, amorphous layer thickness, l a, scattering invariant, Q , crystallinity, X c, lateral crystal sizes, L 200 and L 020 , and unit cell parameters a and b were extracted from SAXS and WAXD profiles. Decreasing long period and crystal thickness indicate that thinner secondary crystal lamellae are formed. The decreases in unit cell parameters a and b during isothermal crystallization process suggest that crystal perfection takes place. The changes in the morphological parameters (the invariant, Q , crystallinity, X c, long period, L , and the crystal thickness, l c) during subsequent melting were found to follow a two-stage melting process, corresponding to the dual endotherm behavior in the DSc scan. We conclude that the dual melting peaks are due to the melting of secondary and primary lamellae(first peak) and the subsequent recrystallization-melting process(second peak). Additional minor endothermic peak located at the lowest temperature was also detected and might be related to melting of secondary, thinner and defective lamellae. WAXD showed that during melting, thermal expansion was greater along the b axis than that along the a axis.

关键词：间规聚丙烯结晶熔化晶体结构 DcS SAXS WAXD

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 boys are back in town: Rethinking the function of ribosomal DNA repeats in the genomic era

引用

Molecular Plant 2023年第3期16卷 514-516页

作者： Francesca B.Lopez Peter c.McKeown Antoine Fort Galina Brychkova charles Spillane Genetics and Biotechnology Laboratory Plant&AgriBiosciences Research Centre(PABC)Ryan InstituteUniversity of GalwayH91 REW4 GalwayIreland Present address:Department of Plant Biology and Genome center University of CaliforniaDavisUC Davis Genome CenterDavisCA 95616USA

Next-generation sequencing technological advances,affording high-throughput,scalable,and fast assemblies,have enabled genome editing techniques that allow us to remove,insert,and modify genes for rapid and precise fun... 详细信息

关键词： remove precise function

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

The crystallization Behavior Regulating Nature of Hydrogen Bonds Interaction on Polyamide 6,6 by Poly(vinyl pyrrolidone)

引用

chinese Journal of Polymer Science 2023年第3期41卷 394-404,I0008页

作者： Yang Liu Li Peng Jie-Long Lin Yong Zhou Du-Jin Wang charles c.Han Xian-Bo Huang Xia Dong National-certified Enterprise Technology center Kingfa Science and Technology Co.LTD.Guangzhou 510663China cAS Key Laboratory of Engineering Plastics Beijing National Laboratory for Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBejing 100190China University of chinese Academy of Sciences Beijing 100049China

The crystallization behavior of polyamide 6,6(PA66) under complex flow field is of great importance for its final mechanical ***(vinyl pyrrolidone)(PVP) was applied as crystallization modifying agency to improve processability of *** regulation nature on hydrogen bonds(H-bonds) interaction of PVP was studied upon cooling *** revealed by in situ FTIR,the sample with 5 wt% PVP displays decreased enthalpy change(ΔH) for both the generation of H-bonds and the transition of H-bonds from “disordered” to “ordered” state,which illustrates the molecular mechanism for the regulation of crystallzation ***,2D-WAXD is applied to reveal the evolution of microstructure for sample under external injection *** orientation factor(f_(H)) decreases obviously with the addition of PVP,because the relaxation of chain segments is promoted as well the crystallization is *** above crystallization and microstructure changes during the processing provokes the improvement of processability without the apparent sacrifice of mechanical properties.

关键词： Polyamide 66 Poly(vinyl pyrrolidone) Hydrogen bonds interaction

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

Thick Film circuit Materials

引用

功能材料 1992年第5期 265-269页

作者： charles c.Y.Kuo cTS corporation 7 Swanson Manor Elkhart IN 46516 USA 本刊通讯编委 7 Swanson Manor Elkhart IN 46516 USA

THIcK FILM cIRcUITS most commonly involve the screen printing process of forming a functional composition through a patterned mesh screen onto *** ceramics. The printed film is dried and fired, typically in the range of 500 to 900 ℃ (930 to 1650°F) to sinter the film and adhere it ro the substrate with the desired characteristics for circuit applications. The functional compositions in general include conductors, resistors, and dielectrics. The dielectrics may be used as overglazes, crossovers, capacitors, or multilayers. The term thick film originated from the term thin film. Thin films are deposited by vacuum technology, either by evaporation or sputtering. In the early 1960s, the Bell Tele-

关键词： high

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

Short-term effect of supplemental yeast extract without or with feed enzymes on growth performance, immune status and gut structure of weaned pigs challenged with Escherichia coli lipopolysaccharide

引用

Journal of Animal Science and Biotechnology 2017年第2期8卷 378-390页

作者： Samuel M.Waititu Fugui Yin Rob Patterson Juan c.Rodriguez-Lecompte charles M.Nyachoti Department of Animal Science University of Manitoba201-12 Dafoe RoadWinnipegM6 R3T 2N2Canada canadian Bio-systems Inc. CalgaryAB T2C OJTCanada Atlantic Veterinary college University of Prince Edward IslandCharlottetownPE C1A 4P3Canada

Background： This study investigated the response of piglets receiving a yeast extract without or with a multi-enzyme mixture compared with an antimicrobial growth promoter（AGP） on performance, immune status and gut structure after an E. coli lipopolysaccharide（LPS） challenge. Thirty-six pigs were allotted to six treatments including： a non-challenged control（Ncc）; LPS-challenged control（cc）; cc ＋ AGP; cc ＋ yeast extract; cc ＋ enzymes; and cc ＋ enzymes ＋ yeast extract. On d 7, pigs were bled and thereafter injected with LPS or sterile saline. Blood samples were collected at 6, 48, and 96 h post-challenge. After 96 h post-challenge, pigs were euthanized to obtain duodenal, jejunal and ileal ***： Overall（d 1 to 11）, compared with cc pigs, AGP attenuated the LPS-induced reduction in ADG（P = 0.004）,ADFI（P = 0.03） and gain/feed ratio（P = 0.01）. At 6 h post-challenge, AGP pigs had lower plasma urea N（PUN; P = 0.02）and serum TNF-α concentration（P = 0.07）, and higher platelet count（P = 0.04） and serum IL-10 concentration（P = 0.02） than cc pigs. At 48 h post-challenge, AGP pigs had lower PUN（P = 0.02） than cc pigs, whereas enzymes ＋ yeast extract interacted non-additively（P = 0.001） to reduce PUN. At 96 h post-challenge, AGP pigs had lower PUN（P = 0.02）and higher duodenal（P = 0.03）, jejunal（P = 0.01） and ileal（P = 0.07） villus height than cc pigs. In addition, enzymes ＋yeast extract interacted additively and non-additively to reduce ileal IFN-γ（P 0.10） were observed between AGP and enzymes ＋ yeast extract pigs on other measured parameters except for the downregulation of ileal IFN-γ（P ＆lt; 0.0001） and TNF-α（P = 0.003） in enzymes ＋ yeast extract pigs at 96 h ***： The LPS challenged piglets receiving enzymes ＋ yeast extract showed beneficial responses in gut structure and immunity commensurate with those receiving antibiotics, though the latter had better overall growth performance.

关键词： Antimicrobial growth promoter Feed enzymes Growth performance Immunity Nucleotides Piglets

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

cytotoxicity evaluation and hepatoprotective potential of bioassay guided fractions from Feronia limmonia Linn leaf

引用

Asian Pacific Journal of Tropical Biomedicine 2011年第6期1卷 443-447页

作者： Mahendra jain Rakhee Kapadia Ravirajsinh N Jadeja Menaka c Thounaojam Ranjitsinh V Devkar SH Mishra Herbal Drug Technology Laboratory Pharmacy DepartmentFaculty of Technology and EngineeringThe M.S.University of Baroda Novel Drug Delivery System Laboratory Pharmacy DepartmentFaculty of Technology and EngineeringThe M.S.University of Baroda Division of Phytothrapeutics and Metabolic Endocrinology Department of ZoologyThe M.S.University of Baroda

Objective:To evaluate the cytotoxicity and hepatoprotective potentials of extracts,fractions or isolated compound from the leaves of Feronia limonia(***).Methods:Qualitative phytochemical analysis of extracts,fractions or compound was performed by means of thin layer chromatography and spectroscopic ***%purity of compound was measured by analytical ***,fractions or compound have been individually evaluated for their cytotoxicity effects(10,20,100,250,500,750 and 1 000 μg/mL).Based on the inhibitory concentration(Ic_(50)) obtained from the cell viability assay,graded concentrations of extracts,fractions or isolated compound were assessed(10,20,50,100,200 μg/mL) for its hepatoprotective potential against ccl_4-induced hepatotoxicity by monitoring activity levels of serum glutamatic pyruvatic transaminase(SGPT) and serum glutamic oxaloacetic transaminase(SGOT).Results:Results indicated that the methanol extract of *** was non-toxic and hepatoprotective in nature as compared with the petroleum ether *** acetone fraction of methanolic extract also showed similar properties but the subsequent two fractions were ***,the pure compound isolated from the penultimate fraction of methanolic extract was non-toxic and hepatoprotective in *** investigations(ScOT,ScPT) further corroborated these cytological ***:It can be concluded from this study that *** methanol extract,some fractions and pure isolated compound herein exhibit hepatoprotective ***,cytotoxicity recorded in the penultimate fraction and investigation of structural details of pure compound warrants further study.

关键词： Feronia limonia leaf HepG2 cytotoxicity Hepatoprotective Phytochemical analysis TLc HPLc Hepatoprotective activity SGPT SGOT Isolated compound Spectroscopic assay

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

Tuning the melting point and phase stability of rare-earth oxides to facilitate their crystal growth from the meltv

引用

Journal of Advanced ceramics 2022年第9期11卷 1479-1490页

作者： Matheus PIANASSOLA Kaden L.ANDERSON Joshua SAFIN can AGcA Jake W.McMURRAY Bryan c.cHAKOUMAKOS Jöerg c.NEUEFEIND charles L.MELcHER Mariya ZHURAVLEVA Scintillation Materials Research center The University of TennesseeKnoxville 37996USA Department of Materials Science and Engineering The University of TennesseeKnoxville 37996USA Materials Science and Technology Division Oak Ridge National LaboratoryOak Ridge 37831USA Neutron Scattering Division Oak Ridge National LaboratoryOak Ridge 37831USA Department of Nuclear Engineering The University of TennesseeKnoxville 37996USA

The challenge of growing rare-earth(RE)sesquioxide crystals can be overcome by tailoring their structural stability and melting point via composition *** work contributes to the advancement of the field of crystal growth of high-entropy oxides.A compound with only small REs(Lu,Y,Ho,Yb,Er)_(2)O_(3)maintains a cubic c-type structure upon cooling from the melt,as observed via in-situ high-temperature neutron diffraction on aerodynamically levitated *** the other hand,a compound with a mixture of small and large REs(Lu,Y,Ho,Nd,La)_(2)O_(3)crystallizes as a mixture of a primary c-type phase with an unstable secondary *** of compositions(Lu,Y,Ho,Nd,La)_(2)O_(3)and(Lu,Y,Gd,Nd,La)_(2)O_(3)were grown by the micro-pulling-down(mPD)method with a single monoclinic B-type phase,while a powder of(Lu,Y,Ho,Yb,Er)_(2)O_(3)did not melt at the maximum operating temperature of an iridium-rhenium *** minimization of the melting point of the two grown crystals is attributed to the mismatch in cation *** electron probe microanalysis reveals that the general element segregation behavior in the crystals depends on the composition.

关键词： high-entropy oxides crystallography neutron diffraction crystal growth

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

Fractional Snow/Non-Snow cover Mapping through Incorporation of Thermal Band in Snow Index Design

引用

International Journal of Geosciences 2017年第11期8卷 1404-1416页

作者： B. c. Yadav Kamal jain Geomatics Engineering Group Indian Institute of Technology Roorkee India

Substantial development has been achieved in snow cover delineations through binary mapping techniques. continuous efforts for development and institution of methodologies in fractional snow cover mapping are steadily conducted by the research communities. In this work, the attempts are driven towards the attainment of the same. MODIS (Moderate Resolution Imaging Spectroradiometer) images are worked upon Landsat 8 images under multivariate polynomial regression schemes utilizing corresponding count of pixels in a test region of Himachal Pradesh. 11.00 μm centered waveband is employed to develop a scheme for snow mapping followed by a qualitative and quantitative comparison with NDSI and S3 snow index where the values of correlation coefficient between fractional snow cover and index values have been obtained as 77.04%, 78.82% and 85.15% for NDSI, S3 and our scheme respectively. Exponential empirical relationships have been tried to be employed to attain improvements in prediction of snow cover followed by a test of correlation between true and theoretical fractional snow cover values. An improvement in degree of correlation is obtained over the conventional methodologies which serves for the verification of scheme employed and empirical relationship defined, collectively. The results provide a scope for improvements and investigations in the subject of fractional snow cover mapping.

关键词： NDSI S3 Fractional Snow Mapping

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

Understanding the role of endothelial cells in brain tumor formation and metastasis: a proposition to be explored for better therapy

引用

Journal of the National cancer center 2023年第3期3卷 222-235页

作者： Tejas Girish Agnihotri Sagar Salave Tanuja Shinde Induri Srikanth Vijay Gyanani Jeffrey c.Haley Aakanchha jain Department of Pharmaceutics National Institute of Pharmaceutical Education and Research(NIPER)-AhmedabadPalajIndia Long Acting Drug Delivery Celanese CorporationIrvingUnited States

Glioblastoma is one of the most devastating central nervous system *** a highly vascular brain tumor,it is distinguished by aberrant vessel *** lends credence to the idea that endothelial cells(Ecs)linked with glioblastoma vary fundamentally from Ecs seen in the healthy human *** effectively design an antiangiogenic treatment,it is crucial to identify the functional and phenotypic characteristics of tumor-associated *** Ecs associated with glioblastoma are less prone to apoptosis than control cells and are resistant to cytotoxic ***,Ecs associated with glioblastoma migrate more quickly than control Ecs and naturally produce large amounts of growth factors such as endothelin-1,interleukin-8,and vascular endothelial growth factor(VEGF).For designing innovative antiangiogenic drugs that particularly target tumor-related Ecs in gliomas,it is critical to comprehend these distinctive features of Ecs associated with *** review discusses the process of angiogenesis,other factors involved in the genesis of tumors,and the possibility of Ecs as a potential target in combating *** also sheds light on the association of tumor microenvironment and Ecs with *** review,thus gives us the hope that neuro endothelial targeting with growth factors and angiogenesis regulators combined with gene therapy would open up new doorways and change our traditional perspective of treating cancer.

关键词： Angiogenesis Gene therapy Growth factors Metastasis Neuro endothelial cells

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

中美花生收获机械化技术现状与发展分析

引用

农业机械学报 2017年第4期48卷 1-21页

作者：陈中玉高连兴 cHEN charles BUTTS c L 沈阳农业大学工程学院沈阳110866 盐城工业职业技术学院汽车工程学院盐城224005 奥本大学农学院奥本al36849 美国农业部农业研究局国家花生研究实验室道森ga31742

收获是花生生产关键环节,用工量占整个生产过程60%以上,机械化收获是一个国家花生生产水平的重要体现。中国和美国同是世界重要的花生生产与出口大国,但因花生生产水平特别是收获机械化水平差距悬殊,从而导致花生出口的国际竞争力不同... 详细信息

收获是花生生产关键环节,用工量占整个生产过程60%以上,机械化收获是一个国家花生生产水平的重要体现。中国和美国同是世界重要的花生生产与出口大国,但因花生生产水平特别是收获机械化水平差距悬殊,从而导致花生出口的国际竞争力不同。美国两段式机械化收获方式及其先进的花生收获机械化技术,使花生生产高产优质高效、国际市场竞争优势明显,而中国多种花生机械化收获方式并存,收获机械化水平相对较低,从而制约了花生生产效益和出口竞争力。基于大量文献的系统分析、中国花生生产实地调研以及美国花生生产和收获机械化的实地考察与综合分析,综述了中国和美国花生生产及其收获机械化发展现状,分别阐述了中国和美国最新花生起收机、捡拾收获机等机器的类型、总体结构型式和主要性能参数等;分析了花生收获机械关键装置的结构原理与特点;综合分析了美国花生收获机械化发展历程以及快速发展的主要动因,中国花生收获机械化发展的主要制约因素;提出了中国花生收获机械化发展动态。对深入了解中国和美国花生收获机械化技术现况及其发展历程,进行中国花生收获机械化发展总结,在借鉴美国成功经验基础上因地制宜地采取措施,加速发展我国花生收获机械化,具有一定的参考价值。

关键词：花生收获机械起收机捡拾收获机中国美国

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：