检索结果-南通市图书馆

Ecological-breaking zone originates and its ecosystems reconstruction in arid area

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 1996年第2期8卷 203-211页

作者： Huang Peiyou Lu Zili(Biology department of Xinjiang university,Urumqi 830046,China) Biology department Xinjiang University Urumqi 830046 China

In the process of arid land exploitation, the landscape of desert is divided into three types. Oasis is rising,the area of uneffected area keeps its original state,the serious degenerated area where is only limited between oasis and desert, but not overall. Its relationship with the neighbor region, the zone of ecological-breaking region or ecological rift valley is not successive. . Its ecological effect endangered the arid land overall. Rehabilitating vegetation is the basic measure for abatement. The authors proposed a new tactics that based on the properties of vegetation. Depending on the local water sources and partly regulating the composition of environmental factor to satisfy the requirement of desert community, the rehabilitate vegetation should be realized.

关键词： arid area ecological-breaking zone ecosystems reconstruction.

ISOMORPHISMS OF GL_3 OVER COMMUTATIVE RINGS

在线全文

学校读者我要写书评

暂无评论

Science China mathematics 1988年第1期31卷 7-14页

作者：李福安李尊贤 Institute of mathematics Academia Sinica Beijing department of mathematics Shaanxi Normal University Xi'an

In this paper, we discuss the necessary and sufficient conditions in which there exist exceptional isomorphisms between E3（A） and E3（R） and between GL3（A） and GL3（R） for commutative rings A and R. A counterexample shows that two rings that are not isomorphic may have isomorphic tinear groups. This partly solves an open problem posed at the conference on abstract homomorphisms of algebraic groupsrs.

关键词： GL ISOMORPHISMS OF GL3 OVER COMMUTATIVE RINGS

The Synthesis of Gallic Esters of Higher Fatty Alcoholsunder Solvent-Free Conditions Using Microwave Irradiation

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1999年第11期10卷 915-916页

作者： Hai Xia LIN Li Xue Zhang Liang Shi CHENG(department of Chemistry, Wenzhou normal College, Wenzhou 325003) department of Chemistry Wenzhou Normal College Wenzhou 325003 China

The reactions of gallic acid with higher fatty alcohols are acceterated by microwaves under solvent-free conditions in the presence of p-toluenesulfonic acid to afford a high yield synthesis of higher fatty alcohol ga... 详细信息

关键词： gallic ester Montmorillonite K 10 microwave irradiation

在线全文

学校读者我要写书评

暂无评论

二重非交换时空与二重复对称引力理论

物理学报 2004年第9期53卷 2846-2851页

作者：吴亚波邵颖董鹏辽宁师范大学物理系大连116029 大连理工大学物理系大连116023

通过引入二重复对称度规张量 ,建立了一种二重复对称引力理论 .从一个二重实的作用量出发 ,导出了静态球对称二重复度规的具体表达式 .该理论扩展了Moffat结果 ,不仅自然地得到了双曲复对称引力理论 ,而且把著名的Schwarzschild解作为... 详细信息

通过引入二重复对称度规张量 ,建立了一种二重复对称引力理论 .从一个二重实的作用量出发 ,导出了静态球对称二重复度规的具体表达式 .该理论扩展了Moffat结果 ,不仅自然地得到了双曲复对称引力理论 ,而且把著名的Schwarzschild解作为特殊情况包含在其中 ,并且在线性化的弱场近似下自动摆脱了Moffat理论中存在的负能鬼态问题 .进一步 ,通过将二重复坐标推广到满足二重非对易关系以及将Moyal星积二重化。

关键词：非交换几何复对称度规非对易坐标引力场作用量量子场论

SUPER-ISOMETRICALLY DILATABLE OPERATORS

在线全文

学校读者我要写书评

暂无评论

Science China mathematics 1989年第12期32卷 1447-1457页

作者：孙顺华余大海 department of mathematics Sichuan University

The notion of super-isometric dilation is introduced and some elementary properties of this dilation are established. It is shown that the Bergman shift is super-isometrically dilatable, and it is proved, in addition, that for φ,ψ and f in H~∞(D), is unitarily equivalent to M_f iff φ=ψ=f=const. provided some finite condition is satisfied.

关键词： operator super-isometric dilation Bergman shift Hardy space.

关于指数丢番图程a^x+b^y=c^z的一个Jacobi符号(英文)

在线全文

学校读者我要写书评

暂无评论

吉首大学学报（自然科学版） 2004年第1期25卷 1-2,15页

作者：乐茂华湛江师范学院数学系

设r是大于 1的奇数 ,u ,v是适合 2 ｜u ,gcd(u ,v) =1,u >2rv/π的正整数 .又设a ,b ,c是适合a+b - 1=(u+v - 1) r 以及c=u2 +v2 的正整数 .确定了Jacobi符号的值 .这一结果有助于指数Diophantine方程ax+by =cz

关键词：指数丢番图程 Jacobi符号奇数互质数

On the Thinnes of Non-tangential Sets

在线全文

学校读者我要写书评

暂无评论

Wuhan university Journal of Natural Sciences 1997年第1期2卷 32-36页

作者： Zhang Yiping department of mathematics, Wuhan university, 430072 Wuhan, China

Let Ω R d and ξ∈Ω. Let E be any non tangential subset of Ω.We prove that if E is internal thin at ξ, then it is minimal thin at any minimal Martin boundary point of Ω.

关键词： Martin boundary thin set minimal thinness

Comparative efficiency analysis of different nonlinear modelling strategies to simulate the biaxial response of RC columns

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2012年第4期11卷 553-566页

作者： Hugo Rodrigues Humberto Varum António Arêde Aníbal Costa university of Aveiro Civil Engineering Department Faculty of Natural Sciences Engineering and Technology-Oporto Lusophone University Civil Engineering department Faculty of Engineering University of Porto

The performance of different nonlinear modelling strategies to simulate the response of RC columns subjected to axial load combined with cyclic biaxial horizontal loading is compared. The models studied are classified into two categories according to the nonlinearity distribution assumed in the elements： lumped-plasticity and distributed inelasticity. For this study, results of tests on 24 columns subjected to cyclic uniaxial and biaxial lateral displacements were numerically reproduced. The analyses show that the global envelope response is satisfactorily represented with the three modelling strategies, but significant differences were found in the strength degradation for higher drift demands and energy dissipation.

关键词： RC columns non-linear behaviour biaxial bending fibre modelling

Structure and function of aggrecan

在线全文

学校读者我要写书评

暂无评论

Cell Research 2002年第1期12卷 19-32页

作者： CHRIS KIANI, LIWEN CHEN, YAO JIONG WU, ALBERT J YEE, BURTON B YANG, Sunnybrook and Women’s College Health Sciences Centre and department of Laboratory Medicine and Patobiology, 2.department of Surgeny, Faculty of Medicine, university of Toronto, Canada Sunnybrook and Women' s College Health Sciences Centre and department of Laboratory Medicine and Pathobiology University of Toronto Canada Sunnybrook and Women' s College Health Sciences Centre and department of Surgeny Faculty of Medicine University of Toronto Canada

Aggrecan is the major proteoglycan in the articular cartilage. This molecule is important in the proper functioning of articular cartilage because it provides a hydrated gel structure (via its interaction with hyaluronan and link protein) that endows the cartilage with load-bearing properties. It is also crucial in chondroskeletal morphogenesis during development. Aggrecan is a multimodular molecule expressed by chondrocytes. Its core protein is composed of three globular domains (G1, G2, and G3) and a large extended region (CS) between G2 and G3 for glycosaminoglycan chain attachment. G1 comprises the amino terminus of the core protein. This domain has the same structural motif as link protein. Functionally, the G1 domain interacts with hyaluronan acid and link protein, forming stable ternary complexes in the extracellular matrix. G2 is homologous to the tandem repeats of G1 and of link protein and is involved in product processing. G3 makes up the carboxyl terminus of the core protein. It enhances glycosaminoglycan modification and product secretion. Aggrecan plays an important role in mediating chondrocyte-chondrocyte and chondrocyte-matrix interactions through its ability to bind hyaluronan.

关键词： Proteoglycan chondroitin sulfate glycosaminoglycan G1 domain G3 domain.