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SHRIMP ages of detrital zircons from the Changcheng System in the Ming Tombs area,beijing:Constraints on the protolith nature and maximum depositional age of the Mesoproterozoic cover of the North china Craton

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Chinese Science Bulletin 2003年第22期48卷 2500-2506页

作者： WAN Yusheng1,2, ZHANG Qiaoda1 & SONG Tianrui1 1. Institute of Geology, Chinese Academy of Geological Sciences, beijing 100037, china 2. beijing SHRIMP Laboratory, beijing 100037, china Correspondence should be addressed to Wan Yusheng (e-mail: wanyusheng@***) Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China

The Mesoproterozoic Changcheng System is widely distributed in the North china Craton. Determining its time of deposition and sources is important to understand the Precambrian crustal evolution of the North china Craton. This paper suggests age distribution patterns for detrital zircons from clastic sediments of the Changcheng System in the Ming Tombs area, beijing. Samples of feldspar-bearing sandstone (CHc-2) and pure sandstone (CHc-9) were collected from the Changzhougou Formation, which constitutes the basal part of the Changcheng System. Detrital zircons show an age range from 2.35 to 2.60 Ga. However, sample CHc-9 in the upper Changzhougou Formation also contains some zircons with ages of 1.9-1.8 Ga and 2.3-2.1 Ga. The age patterns lead to the following conclusions: (1) Most of the detrital material came from a source area composed predominantly of ~2.5 Ga continental crust of the North china Craton; (2) 1.9-1.8 Ga reflects the age record of Palaeoproterozoic continent-continent collisional event in the North china Craton; and (3) the oldest age for deposition of the Changcheng System is 1.8 Ga.

关键词：锆石原岩中国北部地区地壳演变

From quantum spectra to classical orbits: Varying rectangular billiards

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Progress in Natural Science:Materials International 2008年第8期18卷 927-930页

作者： Jun Lu * Department of Foundational Science, beijing Union University, beijing 100101, china Institute of Theoretical Physics, Chinese Academy of Sciences, beijing 100080, china Department of Foundational Science Beijing Union University Beijing 100101 China Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100080 China

The quantum-spectrum function is introduced by means of the eigenvalues and the eigenfunctions in the system of varying rectangular billiards. It is found that the Fourier transform of the quantum-spectrum function corresponds with the classical orbits in the system. These results give new evidence about the classical-quantum correspondence.

关键词： Quantum spectrum Classical-quantum correspondence Semiclassical physics

TEM OBSERVATION OF LOCAL DEFORMATION BAND AT CRACK TIP

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Acta Metallurgica Sinica(English Letters) 1992年第3期5卷 147-153页

作者： YAO Kefu University of Science and Technology beijing,beijing,chinaTANG Naivong CHEN Nanping Tsinghua University,beijing,china beijing Univ of Science and Technology Beijing China

The thin foil specimen of a ferrite-austenite duplex stainless steel was tensiled under transmis- sion electron microscope(TEM).It was found that both in ferrite and austenite the local deformation band at crack tip was formed near to the crack propagating *** forma- tion was related with the crack tip Schmid factor,dislocation shielding,latent hardening and hardening *** the crack tip emitted dislocations to a slip system by the action of pure mode Ⅱ stress resolute,and the decreasing rate of hardening coefficient was suitable,lo- cal deformation band was easy to form.

关键词： crack tip local deformation band dislocation shielding

Palaeogene Biostratigraphic Characteristics of Red Basins In Western Henan and Its Adjacent Areas, With an Outline of Palaeogene Palaeobiogeographic Provinces of china

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Acta Geologica Sinica(English Edition) 1992年第1期66卷 101-117页

作者： Du Hengjian Ma Ancheng Cheng Jie Wu Weimin china University of Geosciences, beijing beijing Normal University china University of Geosciences, beijing Institute of Crustal Dynamics, State Seismological Bureau, beijing china University of Geosciences Beijing China

This article is a preliminary summary of Paleogene biostratigraphy of the Liguanqiao, Tantou andYuanqu basins, with a new proposal for Paleogene paleobiogeographic provinces of china. On the basis of asynthetic analysis of the geological data, characters of the mammalian assemblages and their comparisons withother corresponding faunas, a new scheme on Paleogene biostratigraphic subdivision of the basins has been putforward here. Based on differences of biostratigraphic sequences, characteristics of mammalian assemblagesand directions of faults controlling Paleogene basins in china, six Paleogene paleobiogeographic provinces ofchina have been proposed in this paper, that is: Tianshan-Yinshan-Tumen Province; Tarim-North china Prov-ince; Kunlun-Qinling Province, Yangtze Province, Nanling and Southeastern Coastal Province, Qinghai andTibet Province.

关键词： With an Outline of Palaeogene Palaeobiogeographic Provinces of china

Preparation of a Novel Micro/nano Tubes via Electrospun Fiber as a Template

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Journal of Materials Science & Technology 2004年第5期20卷 613-616页

作者： Taiqi LIUSchool of Materials and Chemical Engineering, beijing Institute of Petro-chemical Technology, beijing 102617, china Sch. of Mat. and Chem. Eng. Beijing Inst. of Petrochem. Technol. Beijing 102617 China

Poly (para-xylylene) hollow fibers with inner diameters can be prepared via template fibers electrospun from solutions. The PPX is deposited from the vapor phase and the template fiber is selectively removed by heat treatment or solvent extraction. The PPX is partially crystalline and the crystal modification depending on the route is used to extract the template fiber. The thermal stability of the hollow fibers is only slightly reduced relative to the bulk material and the same holds for the UV-stability.

关键词： Electrospinning Fiber Chemical vapor deposition Physical vapor deposition Crystal Conductivity

Entropy number and non-linear approximations on multivariate Besov space by manifolds of finite pseudo-dimension

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Progress in Natural Science:Materials International 2006年第3期16卷 260-265页

作者： LONG Jingfan and FANG Gensun (School of Mathematical Sciences, beijing Normal University, beijing 100875, china Department of Computer Science, Information Technology Institute, beijing 100101, china) [a]School of Mathematical Sciences Beijing Normal University Beijing China [b]Department of Computer Science Information Technology Institute Beijing China

We determine the asymptotic order of entropy number and optimal non -linear approximations of anisotropic periodic Besov class of Bpθr(Td') (1≤p≤∞,1≤0≤∞) by manifolds of finite pseudo-dimension in the metric Lq... 详细信息

关键词： Pseudo-dimension anisotropic Besov class of functions entropy number nonlinear width.

Investigation on Coal-Oxygen Scrap Melting Process

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International Journal of Minerals,Metallurgy and Materials 1998年第2期12卷 61-64页

作者： Rong Xhu Yanhui Sun Yongquan Qiu Metallurgy School, UST beijing, beijing 100083, china Metallurgy School UST Beijing Beijing 100083 China

Investigation on the coal-oxygen scrap melting process shows that using internal-combustion coal-oxygen burner to melt scrap is feasible. Among four types of coal-oxygen furnaces-oxygen burner melting furnace is better than other types on the quotas of process. The metal yield is 95%～97%, the melt down carbon and sulphur contents are >1.0% and china.

关键词： scrap melting coal-oxygen burner steelmaking

Extrusion Upsetting Multiple Processing in Sandglass Die

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Rare Metals 2001年第1期20卷 62-65页

作者： Wenlin Lu, Yong Wang, Zezhou Feng, Jintao Hai (beijing Research Institute of Mechanical & Electrical Technology, beijing 100083, china Academy of Machinery Science and Technology, beijing 100044, china) beijing Res Inst Mech & Elect Technol Beijing 100083 Peoples R China Acad Machinery Sci & Technol Beijing 100044 Peoples R China

A new method of getting ultrafine grain size has been investigated, which is called 'Extrusion Upsetting Multiple Processing in Sandglass Die' or 'Sandglass Extrusion' (SE). Since the shape of tested billet can remain unchanged after SE, the billet can be extruded repeatedly in order to get large plastic strain. The ultrafine grain size can be obtained in the billet material due to the large plastic strain and the dynamic recrystallization during SE. The experiments on SE of Zn-5% Al alloy have been done. The SE technology, microstructures, microhardness and superplasticity of tested material after SE have been studied. The experimental results show that the equal-axial ultrafine microstructures can be introduced to the bulk test material during sandglass extrusion. The high strain rate superplasticity can be realized.

关键词： sandglass extrusion ultrafine grain large plastic strain superplasticity Zn-Al alloy

Fiducial inference in the pivotal family of distributions

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Science china Mathematics 2006年第3期49卷 410-432页

作者： XU Xingzhong & LI Guoying Department of Mathematics, beijing Institute of Technology, beijing 100081, china Academy of Mathematics and Systems Science, Chinese Academy of Sciences, beijing 100080, china 1. Department of Mathematics Beijing Institute of Technology Beijing 100081 China 2. Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China

In this paper a family, called the pivotal family, of distributions is considered.A pivotal family is determined by a generalized pivotal model. Analytical results show that a great many parametric families of distributions are pivotal. In a pivotal family of distributions a general method of deriving fiducial distributions of parameters is proposed. In the method a fiducial model plays an important role. A fiducial model is a function of a random variable with a known distribution, called the pivotal random element, when the observation of a statistic is *** method of this paper includes some other methods of deriving fiducial distributions. Specially the first fiducial distribution given by Fisher can be derived by the method. For the monotone likelihood ratio family of distributions, which is a pivotal family, the fiducial distributions have a frequentist property in the Neyman-Pearson view. Fiducial distributions of regular parametric functions also have the above frequentist property. Some advantages of the fiducial inference are exhibited in four applications of the fiducial distribution. Many examples are given, in which the fiducial distributions cannot be derived by the existing methods.

关键词： confidence bounds, fiducial distributions, fiducial model, frequentist prop-erty, generalized pivotal model, pivotal family of distributions, testing hypotheses.