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HIGH TEMPERATURE COMPOSITES

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Acta Metallurgica Sinica(English Letters) 1995年第Z1期8卷 467-476页

作者： M. V. Nathal (NASA Lewis Research Center Cleveland OH. usa) NASA Lewis Research Center Cleveland United States

The purpose of this paper is to review the current state of development of new composite materials for advanced aircraft engines. The advantages and disadvantages of ***-base, and MoSi_2-base composites as replacements for today's Ni-base superalloys are discussed from the standpoint of key technical issues. current status, and future directions. Results describing progress in both improved understanding of the mechanisms of deformation and fracture, and improved material performance will be covered.

关键词： composites. Ti alloys Ti-aluminides NiAl MoSi_2-base jet engines

INTERIOR ERROR ESTIMATES FOR NONCONFORMINGFINITE ELEMENT METHODS OF THE STOKES EQUATIONS

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Journal of Computational Mathematics 1999年第5期17卷 475-494页

作者： Xiao-bo Liu(Department of Mathematics and Computer Science Clarkson University Box 5815, Potsdam,NY 13699-5815, usa) Clarkson University 美国

Interior error estimates are derived for nonconforming stable mixed finite element discretizations of the stationary Stokes equations. As an application, interiorconvergences of difference quotients of the finite element solution are obtained forthe derivatives of the exact solution when the mesh satisfies some translation invariant condition. For the linear element, it is proved that the average of thegradients of the finite element solution at the midpoint of two interior adjacenttriangles approximates the gradient of the exact solution quadratically.

关键词： Interior error estimates Nonconforming element Stokes equations.

Posterior gut development in Drosophila:a model system for identifying genes controlling epithelial morphogenesis

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Cell Research 1998年第4期8卷 273-284页

作者： LENGYEL JUDITH A XUE JUN LIU (Department of Molecular, Cell and Developmental Biology University of California at Los Angeles, Los Angeles, CA usa, 90095-1606 usa) Department of Molecular Cell and Developmental Biology University of California at Los Angeles Los Angeles USA

The posterior gut of the Drosophila embryo, consisting of hindgut and Malpighian tubules, provides a simple,well-defined system where it is possible to use a genetic approach to define components essential for epithelial *** review here the advantages of Drosophila as a model genetic organism, the morphogenesis of the epithelial structures of the posterior gut, and what is known about the genetic requirements to form these *** overview, primordia are patterned by expression of hierarchies of transcription factors; this leads to localized expression of cell signaling molecules, and finally, to the least understood step: modulation of cell adhesion and cell shape. We describe approaches to identify additional genes that are required for morphogenesis of these simple epithelia, particularly those that might play a structural role by affecting cell adhesion and cell shape.

关键词： Organogenesis cell rearrangement convergent extension hindgut Malpighian tubule

Gene silencing:Double-stranded RNA mediated mRNA degradation and gene inactivation

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Cell Research 2001年第3期11卷 181-186页

作者： TANG WEI, XIAO YAN LUO, VANESSA SANMUELS North Carolina State University, Forest Biotechnology Groap, Raleigh, NC 27695, usa University of North Carolina, Department of Cell and Developmental Biology, ChaPel Hill, NC 27599, usa North Carolina State University Forest Biotechnology Group Raleigh USA Department of Cell and Developmental Biology University of North Carolina Chapel Hill USA

The recent development of gene transfer approaches in plants and animals has revealed that transgene can undergo silencing after integration in the genome. Host genes can also be silenced as a consequence of the presence of a homologous transgene. More and more investigations have demonstrated that double- stranded RNA can silence genes by triggering degradation of homologous RNA in the cytoplasm and by directing methylation of homologous nuclear DNA sequences. Analyses of Arabidopsis mutants and plant viral suppressors of silencing are unraveling RNA-silencing mechanisms and are assessing the role of methy- lation in transcriptional and posttranscriptional gene silencing. This review will focus on double-stranded RNA mediated mRNA degradation and gene inactivation in plants.

关键词： Gene silencing double-stranded RNA methylation homologous RNA transgene.

Total synthesis of(+)-lentiginosine via a key Au catalysis

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Science China Chemistry 2010年第1期53卷 113-118页

作者： CUI Li & ZHANG LiMing Department of Chemistry & Biochemistry,University of California,Santa Barbara,CA 93106,usa Department of Chemistry & Biochemistry University of California Santa Barbara USA

Total syntheses of(+)-lentiginosine and its 8a-epimer using a gold-catalyzed oxidative cyclization as the key step were *** gold chemistry,reported previously in a 4+2 synthesis of piperidin-4-ones,tolerates functiona... 详细信息

关键词： gold total synthesis cyclization oxidation alkaloid

Design　Issues　for　Use　of　Solid　State　Transmitter　Radars　in　the　Terminal　Airspace

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Journal of Systems Engineering and Electronics 1995年第1期6卷 57-64页

作者： E. Lee Cole & Lawrence J. Friz(Westinghouse Electric Corporation, Baltimore, MD, usa) Westinghouse Electric Corporation Baltimore MD USA

Abstract

关键词： Design Use Issues Airspace

Targeting epidermal Langerhans cells by epidermal powder immunization

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Cell Research 2002年第2期12卷 97-104页

作者： DEXIANG CHEN, LENDON G PAYNEPowderJect Vaccines, Inc. 585 Science Drive, Madison, WI 53711, usa PowderJect Vaccines Inc. 585 Science Drive Madison USA

Immune reactions to foreign or self-antigens lead to protective immunity and, sometimes, immune disorders such as allergies and autoimmune diseases. Antigen presenting cells （APC） including epidermal Langerhans cells （LCs） play an important role in the course and outcome of the immune reactions. Epidermal powder immunization （EPI） is a technology that offers a tool to manipulate the LCs and the potential to harness the immune reactions towards prevention and treatment of infectious diseases and immune disorders.

关键词： Langerhans cells dendritic cells vaccines epidermal immunization.

Characterization of Compact Support of Fourier Transform for Orthonormal Wavelets of L^2(R^d)

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Acta Mathematica Sinica,English Series 2005年第4期21卷 855-864页

作者： Zhi Hua ZHANG (Zhihua ZHANG) Department of Mathematics,University of California,Davis,California.95616,usa Department of Mathematics University of California Davis USA

Let{ψμ} be an orthonormal wavelet of L^2（R^d） and the support of a whole of its Fourier transform be Uμsupp{ψμ}=Пi=1^d[Ai, Di]-Пi=1^d（Bi, Ci）, Ai≤Bi≤Ci≤Di. Under the weakest condition that each │ψμ│,... 详细信息

关键词： Orthonormal wavelets Multiresolution analysis Scaling function Compact support

DEVELOPMENT　OF　INCONEL~　ALLOY　783，A　LOW　THERMAL　EXPANSION，CRACK　GROWTH　RESISTANT　SUPERALLOY

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Acta Metallurgica Sinica(English Letters) 1996年第6期9卷 503-507页

作者： J.H.Thndermann(Inco Alloys International, Inc., Huntington, WV 25705, usa ) Inco Alloys Int Inc. Huntington United States

Low thermal expansion superalloys have been used for a number of years in a variety of applications, including gas turbine engines. The low thermal expansion characteristics of the most widely used class of materials are derived from the ferromagnetic characteristics of Ni, Fe, and Co-based austenitic matrices containing little or no *** developments have been aimed at improving the oxidation resistance and stress accelerated grain boundary oxygen (SAGBO) *** alloy 783 is an oxidation resistant, low coefficient of thermal expansion superalloy developed for gas turbine applications. Alloy 783 represents a culmination in the development, of an alloy system with very high alumtnum content that, in addition to forming γ′,causes βaluminide phase precipitation in the austenitic *** type of structure can be processed to resist both SAGBO and general oxidation,while providing low thermal expansion and useful mechanical properties up to 700℃.Key aspects of the alloy's development are presented.

关键词： coefficient of thermal expansion oxidation resistance crack growth resistance,SAGBO INCONEL alloy 783,alloy 718,gamma prime phase beta phase