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On three-dimensional geological modeling and visualization

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science china Earth sciences 2004年第8期47卷 739-748页

作者： WU Qiang1 & XU Hua2.1. Department of Resource Exploitation engineering, china University of Mining and Technology, {2. 100083, china 2. {2. Institute of Petrochemical Technology, {2. 102.17, china 1. Department of Resource Exploitation engineering China University of Mining and Technology 100083 Beijing China 2. beijing Institute of Petrochemical Technology 102617 Beijing China

The technology of 3D geological modeling will bring about great changes in the methods of geological data acquiring, storing, processing and displaying. However, no perfect or convenient software systems have been developed up to now since the geologic data which re-flect geological entities bear the feature of diversity, uncertainty and complexity. Some supervoxel models, mathematical models of fault and geometrical models of fold have been contrived so as to show the space geometric configuration of the complicated geologic structures. The application-oriented system architecture for 3D geological modeling is established; and a novel design concept based on spatial data processing is also proposed with the technology of solid modeling as its core and the application of models as its objective. Theories and methods for 3D geological modeling will hopefully be enriched and developed. In the light of these theories and methods, a feature-based navigation visualization technique is also put forward in the paper. By integrating geo-database, graphics libraries and KBS with 3D dynamic simulation systems, geologists will be able to capture the partial characteristics and whole structure embodied in the geological data in a direct-viewing, figurative and accurate manner.

关键词： 3D geological modeling,geometrical model,system architecture,visualization

Presenting degenerate Ringel-Hall algebras of type B

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science china Mathematics 2012年第5期55卷 949-960页

作者： FAN LiJuan1 & ZHAO ZhongHua2.1Department of Mathematics,beijing Normal University,beijing 100875,{2. 2.epartment of Mathematics and computer science,school of science,beijing University of Chemical Technology,beijing 10002.,{2. 1. Department of Mathematics Beijing Normal University Beijing 100875 China2. Department of Mathematics and Computer Science School of Science Beijing University of Chemical Technology Beijing 100029 China

We give a presentation for the degenerate Ringel-Hall algebras of type B by studying the corresponding generic extension monoid *** an application,it is shown that the degenerate Ringel-Hall algebras of type B admit m... 详细信息

关键词： degenerate Ringel-Hall algebras generic extension monoid algebras Auslander-Reiten quivers Frobenius morphism

Effects of the CNTF-collagen gel-controlled delivery system on rat neural stem/progenitor cells behavior

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science china(Life sciences) 2010年第4期53卷 504-510页

作者： YANG ZhaoYang1, QIAO Hui2.& LI XiaoGuang1,3 1school of Biological science and Medical {2., Beihang University, beijing 100191, china 2.ublic Heath school, Ningxia Medical University, Yinchuan 750004, china 3beijing Institute for Neuroscience, Capital Medical University, beijing 100069, china 1. school of Biological science and Medical {2. Beihang University Beijing 100191 China2. Public Heath School Ningxia Medical University Yinchuan 750004 China3. Beijing Institute for Neuroscience Capital Medical University Beijing 100069 China

The injury of central nervous system (CNS) usually causes the cavity formation. Although transplantation of neural stem/precursor cells (NSPCs) into the lesioned area of CNS has been shown to be implicated in the functional restoration, the therapeutic result is limited by the poor survival of NSPCs as well as their insufficient proliferation and differentiation abilities. Type-1 collagen is considered as a candidate scaffold or drug delivery system to overcome the aforementioned obstacle. This study observed the effects of the CNTF (ciliary neurotrophic factor)-collagen gel-controlled delivery system and daily addition of soluble-form CNTF on the NSPC survival, migration, proliferation and differentiation. The results showed that, within 12.h of the initial co-culture, CNTF was released in a burst pattern, then the CNTF-collagen gel-controlled delivery system stably released CNTF for up to 12.d. The cell viability test, together with immunohistochemistry, RT-PCR and Western blotting, showed that the CNTF-collagen gel-controlled delivery system supported the NSPCs seeded on the surface of collagen gel survival and facilitated their migration and proliferation. The daily addition of soluble-form CNTF to the medium had similar effects to the CNTF-collagen gel-controlled delivery system, but large quantities of soluble-form CNTF were consumed during the entire process. Taken together, the CNTF-collagen gel-controlled delivery system not only provides a physical scaffold for the transplanted NSPCs to adhere and migrate, but also facilitates the NSPC survival, growth and proliferation, simultaneously reducing the consumption of the expensive growth factors. This system may be used to enhance the microenvironment in the lesioned area of CNS.

关键词： spinal cord neural stem/progenitor cells control release type-1 collagen CNTF

A software architecture centric self-adaptation approach for Internetware

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science in china(Series F) 2008年第6期51卷 722-742页

作者： MEI Hong1,2. HUANG Gang1,2. LAN Ling1,2.& LI JunGuo1,2.1 Key Laboratory of High Confidence Software Technologies (Peking University), Ministry of Education, beijing 100871, china {2. of Electronics engineering and computer science, Peking University, beijing 100871, china 1. Key Laboratory of High Confidence Software Technologies (Peking University) Ministry of Education Beijing 100871 China 2. school of Electronics engineering and {2. science Peking University Beijing 100871 China

Being one of the basic features of Internetware, self-adaptation means that the software system can monitor its runtime state and behavior and adjust them when necessary according to pre-defined policies. Focusing on the three fundamental issues of self-adaptation, including the scope, operability and trustworthiness, a software architecture （SA） centric approach for Internetware＇s self-adaptation is presented in this paper. All of the self-adaptive actions, i.e. monitoring, analyzing, planning and executing, are performed based on SA. In detail, runtime state and behavior of Internetware are represented and changed in the form of runtime soft- ware architecture. The knowledge for self-adaptation is captured, organized and reasoned in the form of SA so that automatic analysis and decision-making are achieved.

关键词： Internetware self-adaptation software architecture middleware

An algorithm to compute maximal contractions for Horn clauses

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science china(Information sciences) 2011年第2期54卷 244-257页

作者： LUO Jie & LI Wei State Key Laboratory of Software Development Environment, school of computer {2. and Technology, Beihang University, beijing 100191, china 1. State Key Laboratory of Software Development Environment School of Computer Science and Technology Beihang University Beijing 100191 China

In the theory of belief revision, the computation of all maximal subsets (maximal contractions) of a formula set with respect to a set of facts is one of the key problems. In this paper, we try to solve this problem by studying the algorithm to compute all maximal contractions for Horn clauses. First, we point out and prove the conversion relationship between minimal inconsistent subsets of union of the formula set and the set of facts and maximal contractions of the formula set with respect to the set of facts. Second, we prove a necessary condition of a set of Horn clauses to be minimal inconsistent. Then, based on these two conclusions, we propose an interactive algorithm to enumerate all minimal inconsistent subsets of a given set of Horn clauses and a second algorithm to compute maximal contractions from these minimal inconsistent subsets. Finally, we proposed an interactive algorithm to compute maximal contractions for Horn clauses by composing the above two algorithms.

关键词： maximal contraction minimal inconsistent set minimal subtraction Horn clause

Surface characteristics of rapidly solidified nickel-based superalloy pow-ders prepared by PREP

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Rare Metals 2003年第4期22卷 309-314页

作者： CHEN Huanming , HU Benfu , and LI Huiying1) school of Materials science and {2., University of science and Technology beijing, beijing 100083, china2. school of Physics and Electrical Information {2., Ningxia University, Yinchuan 75002., china school of Materials science and {2. University of Science and Technology Beijing Beijing 100083 Chins

The surface microstructure and the surface segregation of FGH 95 nickel-basedsuperalloy powders prepared through plasma rotating electrode processing (PREP) have beeninvestigated by using SEM and AES. The results indicate that the surface microstructure of powderschanges from dendrite into cellular stricture as the particle size of powders decrease, and thepredominant precipitates solidified on the particle surfaces were identified as MC' type carbidesenriched with Nb and Ti. It was also indicated that along with the depth of particle surfaces, thesegregation layer of S, C and O elements are thick, and that of Ti, Cr elements are thin for largesire powders while they are in reverse for median size particles.

关键词： FGH 95 nickel-based superalloy powders surface characteristics microstructure plasma rotating electrode processing

Performance Modeling and Approximate Analysis of Multiserver Multiqueue Systems with Poisson and Self-similar Arrivals

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Journal of University of science and Technology beijing 2001年第2期8卷 145-151页

作者： Zhiguang Shan, Chuang Lin, Yang Yang, Yan Wang (Information engineering school, University of {2. and Technology beijing, beijing 100083, china) (Department of computer {2. and Technology, Tsinghua University, beijing 100084, china) Univ Sci & Technol beijing Informat Engn Sch Beijing 100083 Peoples R China Tsinghua Univ Dept Comp Sci & Technol Beijing 100084 Peoples R China

The problem of state space explosion is still ran outstanding challenge in Markovian performance analysis for multiserver multiqueue (MSMQ) systems. The system behavior of a MSMQ system is described using stochastic high-level Petri net (SHLPN) models, and an approximate performance analysis technique is proposed based on decomposition and refinement methods as well as iteration technique. A real MSMQ system, Web-server cluster, is investigated. The performance of an integrated scheme of request dispatching and scheduling is analyzed with both Poisson and self-similar request arrivals. The study shows that the approximate analysis technique significantly reduces the complexity of the model solution and is also efficient for accuracy of numerical results.

关键词： multiserver multiqueue (MSMQ) system Web-server cluster performance analysis stochastic high-level Petri net (SHLPN) request dispatching request scheduling

Quasi-secure quantum dialogue using single photons

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science china(Physics,Mechanics & Astronomy) 2007年第5期50卷 558-562页

作者： YANG YuGuang1,2.& WEN QiaoYan31 College of computer science and Technology, {2. University of Technology, {2. 10002., china 2.State Key Laboratory of Information Security, Graduate University of the Chinese Academy of sciences, {2. 100049, china 3 school of science, {2. University of Posts and Telecommunications, {2. 100876, china College of computer science Technology Beijing University of Technology Beijing 100022 China State Key Laboratory of Information Security Graduate University of the Chinese Academy of Sciences Beijing 100049 China school of science Beijing University of Posts Telecommunications Beijing 100876 China

A quasi-secure quantum dialogue protocol using single photons was proposed. Different from the previous entanglement-based protocols, the present protocol uses batches of single photons which run back and forth between the two parties. A round run for each photon makes the two parties each obtain a classical bit of information. So the efficiency of information transmission can be increased. The present scheme is practical and well within the present-day technology.

关键词： quantum dialogue, single photon, quantum secure direct communication

Effect of the silicon powder content on the properties of Al_2._3-SiC-Me composites

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science china(Technological sciences) 2009年第1期52卷 193-197页

作者： ZHANG ZhiHui1, RUAN GuoZhi1 & CHEN YunBo1,2.1 school of Material science and {2., Shandong University of science and Technology, Qingdao 2.6510, china 2.Institute of Material {2., china Academy of Machinery science and Technology, beijing 100083, china school of Material science and {2. Shandong University of Science and Technology Qingdao 266510 China Institute of Material engineering China Academy of Machinery Science and Technology Beijing 100083 China

By means of transient plastic phase process, the Al2.3-SiC-Me composites were produced throungh adding metal aluminium and silicon-powder to Al2.3-SiC materials. Under the condition of the same content of silicon and aluminium mixed-powder, the effect of silicon powder addition on properties of Al2.3-SiC-Me composites was studied by means of XRD and EPMA analyses in the temperature range of 300℃―1600℃. The results indicated that the content of metal phase in the sample at 1600℃ increases with increasing silicon powder content. At the same time, when the temperature is lower than 1100℃, the strength of samples gradually increases with increasing temperature. However when the temperature is higher than 1100℃, the strength of samples gradually decreases with increasing temperature, and this change is very small. The results also indicated that at the same sintering temperature, the sample with 6% silicon powder has the maximum strength.

关键词： composites strength ceramic