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BEST DIRECT AND CONVERSE RESULTS FOR LAGRANGE-TYPE OPERATORS

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Analysis in Theory and Applications 1995年第2期11卷 76-93页

作者： D. H. Mache D. X. Zhou Univ. of Dortmund Germany and Academia Sinica ChinaUniv. of Dortmund Germany and Academia Sinica China

The aim of this paper is to give direct and converse theorems for the approximation by using a discretely defined method Ln (see D. H. Mache [10], which is a modification of the Lagrange operator. Furthermore we obtain with a matrix construction technique (see M. D. Ye and D. X. Zhou [11]) a Lagrange-type operator n, for which we get a characterization for Lipschitz functions by the approximation rate of these methods.

关键词： BEST DIRECT AND CONVERSE RESULTS FOR LAGRANGE-TYPE OPERATORS

Cluster characters for cyclic quivers

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Frontiers of Mathematics in China 2012年第4期7卷 679-693页

作者： Ming DING Fan XU School of Mathematical Sciences Nankai University Tianjin 300071 China Department of Mathematical Sciences Tsinghua University Beijing 100084 China

We define an analogue of the Caldero-Chapoton map for the cluster category of finite-dimensional nilpotent representations over a cyclic quiver. We prove that it is a cluster character and satisfies some inductive formulas for the multiplication between the generalized cluster variables （the images of objects of the cluster category under this map）. Moreover, we construct a Z-basis for the algebra generated by all generalized cluster variables.

关键词： Cyclic quiver cluster algebra Z-basis

Graben on the Lunar Nearside: Do Dikes Lie Beneath?

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Acta Geologica Sinica(English Edition) 2016年第S1期90卷 175-176页

作者： Amanda L.NAHM German Aerospace Center (DLR)

On the Moon,tectonic structures are concentrated on the nearside,spatially associated with the maria(e.g.,Watters and Johnson,2010),or basalt-filled impact *** graben(or rilles)are long,narrow troughs up to

关键词： Graben on the Lunar Nearside Do Dikes Lie Beneath

Cerberus Fossae, Mars: The Case for Dike Intrusion-related Formation and Modification

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Acta Geologica Sinica(English Edition) 2016年第S1期90卷 173-174页

作者： Amanda L.NAHM Matthew W.PENDLETON Simon A.KATTENHORN German Aerospace Center (DLR) University of Idaho Earth Consultants International University of Alaska Anchorage

Cerberus Fossae(CF)is a large fracture system on Mars that extends for more than 1200 *** structures,or fossae,are southeast of,and oriented approximately radially to,the large shield volcano Elysium ***

关键词： Burr Cerberus Fossae Mars CF

Precision Grinding of Reaction Bonded Silicon Carbide Using Coarse Grain Size Diamond Wheels

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Chinese Journal of Mechanical Engineering 2010年第3期23卷 269-275页

作者： ZHAO Qingliang CHEN Junyun BRINKSMEIER E Centre for Precision Engineering Harbin Institute of Technology Harbin 150001 China Laboratory for Precision Machining University of Bremen Bremen D-28359 Germany

Reaction bonded SiC（RBSiC） is attractive for optical application because of its favorable properties and low fabrication cost. However, the difficultness and cost involved in RBSiC grinding limit its application. The investigation on high efficient and low-cost machining with good grinding quality is desired. Generally, high efficient machining for RBSiC is realized by using coarse grain size grinding wheels, but serious grinding damage is inevitable. In this paper, monolayer nickel electroplated coarse grain size diamond grinding wheels with grain sizes of 46 μm, 91 μm, and 151 μm were applied to the grinding of RBSiC. An electrolytic in-process dressing（ELID） assisted conditioning technique was first developed by using cup shape copper bonded conditioning wheels with grain sizes of 15 μm and 91 μm to generate the conditioned coarse grain size wheels with minimized wheel run-out error within 2 μm, constant wheel peripheral envelop as well as top-flattened diamond grains. Then, the grinding experiments on RBSiC were carried out to investigate the grinding performance and material removal mechanism. The experimental results indicate that the developed conditioning technique is applicable and feasible to condition the coarse grain size diamond wheels under optimal conditioning parameters, and the material removal mechanism involved in RBSiC grinding is the combination of brittle fracture and ductile deformation to generate smooth ground surface. This research is significant for the high efficient and low-cost precision grinding of RBSiC with good ground surface quality.

关键词： precision grinding SiC coarse grain size diamond wheel ELID assisted conditioning material removal mechanism

Classification of hypersurfaces with parallel Mobius second fundamental form in S^(n+1)

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Science China Mathematics 2004年第3期47卷 417-430页

作者： HU Zejun LI Haizhong Department of Mathematics, Zhengzhou University Zhengzhou 450052, China Department of Mathematical Sciences, Tsinghua University, Beijing 100084, China Department of Mathematics Zhengzhou University Zhengzhou China Department of Mathematical Sciences Tsinghua University Beijing China

Let Mn(n≥2) be an immersed umbilic-free hypersurface in the(n+1)-dimensional unit sphere Sn+1. Then Mn is associated witha so-called M(o)bius metric g, and a M(o)bius second fundamental form Bwhich are invariants of Mn under the M(o)bius transformation groupof Sn+*** this paper, we classify all umbilic-free hypersurfaces withparallel M(o)bius second fundamental form.

关键词： parallel Mobius second fundamental form,hypersurface, Mobius metric, Mobius equivalence.

Absorption Enhancement of Ultrathin Crystalline Silicon Solar Cells with Dielectric Si3N4 Nanostructures

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Communications in Theoretical Physics 2019年第11期71卷 1346-1352页

作者： Xin-Yu Tan Can Deng Yi-Teng Tu Li Guan China Three Gorges University College of Materials and Chemical EngineeringKey Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion MaterialsYichang 443002China Lei Sun Department of Physics Science and Technology Hebei UniversityBaoding 071000China College of Elec trical Engineering&New Energy Hubei Provincial Collaborative Innovation Center for New Energy MicrogridYichang 443002China

A design of ultrathin crystalline silicon solar cell with Si3 N4 circular truncated cone holes(CTCs)arrays on the top is *** this article,we perform an optical simulation of the *** finite-difference time-domain method is used to calculate the optical absorption of different periods,radius of top and bottom circles and depth of Si3 N4 *** short-circuit current density generated by the optimized cells(30.17 mA/cm^2)is 32.44%more than the value gained by control group(with flat Si3 N4).Then adding a layer of back silver to allow us to better analyze optical ***,we simulate the optimization of the same configuration of different silicon thicknesses andfind that our structure does enhance the light *** work uses a combined path towards achieving higher photocurrent ultrathin crystalline silicon solar cells by constructing the texture of anti-reflection coating.

关键词： photovoltaic silicon diffraction gratings antireflection coatings

经互会解体后的苏联与东欧经济一体化——挑战与前景

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国际社会科学杂志（中文版） 1993年第1期10卷 95-110页

作者：理夏德·瓦夫尼茨扎克高铦波兰波兹南经济学院

导言 1990年初,一位德国专家得出结论说:"看来经济互助委员会似乎已到了山穷水尽的地步。……综观它的经历,对它最好的希望是:悄悄地埋葬掉老组织。

关键词：经互会可兑换货币德国专家经济合作地区一体化本国货币货币兑换经济发展水平东欧国家合作问题

THE PORTABILITY OF THE DISTRIBUTED RELATIONAL DATA BASE SYSTEM POREL

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Science China Mathematics 1983年第8期 874-883页

作者：周龙骧顾君忠 Department of Computer Science East China Normal University Shanghai Institute of Mathematics Academia Sinica Beijing Department of Computer Science Stuttgart University. West Germany Department of Computer Science Stuttgart University West Germany

This paper studies the portability of the distributed relatienal data base management system and suggests an abstract machine AC as a tool to realize the transportation of POREL. The abstract machine AC consists of three parts: a system programming language PASCAL extended by a subset, an abstract operating system AOS a,nd an abstract communication system ACS, A concise description of AC is given.

关键词： THE PORTABILITY OF THE DISTRIBUTED RELATIONAL DATA BASE SYSTEM POREL