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Experimental and computational approaches on the Lsospecific role of monoester-type internal electron donor for TiCl4/MgCl2 Ziegler-Natta catalysts

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Macromolecular Symposia 2007年第1期260卷 42-48页

作者： Liu, Boping Cheng, Ruihua Liu, Zhen Qiu, Pengyuan Zhang, Shiliang Taniike, Toshiaki Terano, Minoru Tashino, Kunihiko Fujita, Takashi State Key Lab. of Chemical Engineering East China University of Science and Technology Mei Long Road 130 Shanghai P.C. 200237 China School of Materials Science Japan Advanced Institute of Science and Technology 1-1 Asahidai Nomi Ishikawa 923-1292 Japan R and D Section Toho Catalyst Co. Ltd. 3-3-5 Chigasaki-City Kanagawa-Pref. 253-0041 Japan

In this work, a combination of experimental and computational approaches on the isospecific role of monoester-type internal electron donors (ED) such as phenylpropionate (PhP), ethylheptanoate (EH), methylbenzoate (MB), ethylbenzoate (EB) for TiCl4/ED/MgCl2 Ziegler-Natta catalysts had been performed. The propylene polymerization results revealed that the isospecificity of catalysts increases in the following order: PhP 4/ED/MgCl2 and TiCl4/ED/(MgCl2)4 based on density functional theory (DFT) method was carried out. Two kinds of ED coordination on MgCl 2 clusters through either =O or -O- within the monoester-type ED had been disclosed. A perfect correlation between the dipole moment of ED, the coordination bond length of =O... Mg, the competitive coordination from -O- with Mg ion and the isospecificity of the catalysts had been established. Copyright © 2007 WILEY-VCH Verlag GmbH & Co. KGaA,.

关键词： Catalysts

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Demonstration of a Task-flow based Aircraft Collaborative Design Application in Optical Grid

Demonstration of a Task-flow based Aircraft Collaborative De...

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33rd European Conference and Exhibition of Optical Communication

作者： Zhengyu Wang Wei Guo Zhenyu Sun Yaohui Jin Weiqiang Sun Weisheng Hu Xinhua Lin Min-You Wu Hong Liu San Fu Jun Yuan Chunming Qiao State Key Lab on Fiber-Optic Local Area Networks and Advanced Optical Communication systems Shanghai Jiao Tong University P. R. China 200240 Grid Computing Center Shanghai Jiao Tong University China 200240 Institute of Aerospace Science and Technology Shanghai Jiao Tong University China 200240 Shanghai Supercomputer Center Shanghai China 201203 Computer Science & Engineering State University of New York at Buffalo NY 14260 USA

One task-flow scheduler has been designed to optimally allocate resources for a task-flow based Aircraft Collaborative Design Application in Optical Grid. This scheduler and application has been deployed on an Optical... 详细信息

关键词： Computational modeling Atmospheric modeling Numerical models Performance evaluation Optical design Aerodynamics

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XRD and HRTEM Analyses of the Ball Milled Nanocrystalline FeCo Alloy

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Journal of Wuhan University of technology(Materials Science) 2006年第1期21卷 68-71页

作者：王琦官建国 State Key Lab of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070ChinaSchool of Materials Science and EngineeringJinan UniversityJinan 250022China State Key Lab of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070China

The nanostractures of the ball milled FeCo particles were characterized as functions of the ball milling time （ t ） using quantitative X- ray diffraction （ XRD ）, high resolution transmission electron microscopy （HRTEM） analysis techniques. The results show that the nanocrystalliue bcc FeCo particles are available using carbonyl iron and cobalt powders as the start materials during the high-energy ball milling. At the early stage of ball milling, Co powders are easily mashed into nanocrystalllites, by which the surface of the larger Fe particles of about 80- 150 nm is coated. With t increasing, the refinement of grain size and the incorporation of defects including dislocations, disclinations and grain boundaries happen, and then FeCo alloy with a certain layered structure is formed, finally the layered stractare disappears with the formation of isotropic grains having a steadystate grain size in the nanometer regime after a certain period of t.

关键词： high energy ball milling carbonyl iron cobalt alloy nanocrystalline materials

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Optical VPN Connecting ONUs in Different PONs

Optical VPN Connecting ONUs in Different PONs

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Optical Fiber Communication - OFC 2007 Collocated National Fiber Optic Engineers Conference (OFC 2007), vol.2

作者： Yue Tian Xiangqing Tian Lufeng Leng Tong Ye Yikai Su State Key Lab of Advanced Optical Communication Systems and Networks Department of Electronic Engineering Shanghai Jiao Tong University 800 Dongchuan Rd Shanghai 200240 China New York City College of Technology City University of New York Brooklyn NY 11201 USA

We demonstrate optical-layer virtual private networking in a new super-PON architecture using a dynamic wavelength reflector. The optical VPN enables communications among different PONs.

ISBN: (纸本)1557528306

We demonstrate optical-layer virtual private networking in a new super-PON architecture using a dynamic wavelength reflector. The optical VPN enables communications among different PONs.

关键词： Arrayed waveguide gratings Bit error rate Fiber Bragg gratings Optical amplification Optical networks Passive optical networks Fiber optics and optical communications (060.0060) Fiber optics communications (060.2330) Networks (060.4250)

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Optimal operating conditions and modulation format for 160Gb/s signals in a fiber parametric amplifier used as a slow-light delay line element

Optimal operating conditions and modulation format for 160Gb...

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Optical Fiber Communication - OFC 2007 Collocated National Fiber Optic Engineers Conference (OFC 2007), vol.2

作者： Fangfei Liu Yikai Su Paul L. Voss State Key Lab of Advanced Optical Communication Systems and Networks Department of Electronic Engineering Shanghai Jiao Tong University 800 DongChuan Rd Shanghai 200240 China School of Electrical and Computer Engineering Georgia Institute of Technology 777Atlantic Drive Atlanta GA USA 30332-0250 Georgia Tech Lorraine GT-CNRS UMI2958 2-3 rue Marconi Metz France F-57070

We study optimal operating conditions for 160-Gb/s signals traversing a slow-light delay line based on parametric amplification. Six phase modulated formats are investigated, including CSRZ, PAP-CSRZ, GAP-CSRZ, RZ duo... 详细信息

ISBN: (纸本)1557528306

关键词： Differential phase shift keying Fiber optic amplifiers Modulation Modulation techniques Packet switched networks Phase shift Nonlinear optics (190.0190) Parametric oscillators and amplifiers (190.4970)

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On the quality of service of failure detectors based on control theory

On the quality of service of failure detectors based on cont...

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20th International Conference on advanced Information Networking and Applications

作者： Xiong, Naixue Yang, Yan Chen, Jianxun He, Yanxiang School of Information Science Japan Advanced Institute of Science and Technology Japan Computer Science and Technology School Wuhan University of Science and Technology China State Key Lab of Software Engineering Computer School Wuhan University China

ISBN: (纸本)0769524664

The detection of failures is a fundamental issue for fault tolerance in distributed systems. Recently, many people have come to realize that failure detection ought to be provided as some form of generic service, similar to IP address lookup. However, this has not been successful so far;one of the reasons being the fact that classical failure detectors were not designed to satisfy several application requirements simultaneously. More specifically, traditional implementations of failure detectors are often tuned for running over local networks and fail to address some important problems found in wide-area distributed systems with a large number of monitored components. In this paper, we study the quality of service (QoS) of failure detectors. We first present a novel failure detector scheme combined with control theory that can help in solving or optimizing some problems. Furthermore, this paper discusses the design and analysis of implementing a scalable failure detection service for such large wide-area distributed systems considering dynamically adjusting the heartbeat streams, so that it satisfies the bottleneck router requirements. We further show how the online failure detector control algorithm can be used to design a controller, analyze the theoretical aspects of the proposed algorithm and verify its agreement. Simulation results show the efficiency of our scheme in terms of high utilization of the bottleneck link fast response and good stability of the bottleneck router buffer occupancy as well as of the controlled sending rates. In conclusion, the new failure detector algorithm provides a better QoS than an algorithm that is proposed by Stelling et al [1, 2].

关键词： Telecommunication services

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On designing QoS for congestion control service using neural network predictive techniques

On designing QoS for congestion control service using neural...

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IEEE International Conference on Granular Computing

作者： Xiong, N. Yang, Y. He, Jing He, Yanxiang IEEE Japan School of Information Science Japan Advanced Institute of Science and Technology Japan Department of Computer Science Utah State University Logan UT 84322-4205 United States State Key Lab. of Software Engineering Computer School Wuhan University China

ISBN: (纸本)142440133X

With the ever-increasing data transmission applications recently, considerable efforts have been focused on the design of congestion control scheme for data transmission service to guarantee the quality of service (QoS). The main difficulty in designing an efficient congestion controller for data transmission service stems from the heterogeneous receivers, especially those with large propagation delays in data transfer, which also mean the feedbacks arriving at the source are somewhat outdated and can be harmful to the control actions. This usually leads to a mismatch between the network resources and the amount of admitted traffic. To attack this problem, the present paper describes a novel congestion control scheme that is based on a Back Propagation (BP) neural network technique. We consider a general computer communication model with multiple sources and one destination node. This network-assisted property is different from the existed control scheme in that the data source can predict the dynamic of buffer occupancy of the bottleneck node for which the back control packets experience very long propagation delay and probably cause irresponsiveness of a. data flow. This active scheme makes the control more responsive to the network status. Thus the rate adaptation can be in a timely manner for the sender to react to network congestion quickly. We analyze the theoretical aspects of the proposed algorithm, show how the control mechanism can be used to design a controller to support the data transmission based on feedback of explicit rates' (ER's), and verify this agreement by the simulations. Simulation results show the efficiency of our scheme in terms of quickly response and excellent predictive accuracy.

关键词： neural network applications neural networks traffic control (communication) interconnection networks transportation networks

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Study on the process mechanism in spark plasma sintering

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6th Pacific Rim Conference on Ceramics and Glass technology, PacRim6

作者： Fu, Zhengyi Wang, Kun Tan, Tianya Xiong, Yan He, Daihua Wang, Yucheng Munir, Zuhair A. State Key Lab of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 122 Luoshi Road Hubei Province 430070 China Department of Chemical Engineering and Materials Science University of California Davis CA 95616 United States

ISBN: (纸本)0470081562

The paper presents results on the mechanism of spark plasma sintering (SPS). First, the temperature distribution in the sample and the die in SPS were studied. Under certain conditions, the difference may reach a few hundreds of degrees of centigrade. Controlling of processing parameters can decrease the temperature difference. Second, the process of atomic diffusion due to the effect of the current was also studied. It was found that the atomic diffusion is enhanced at the interface between specimens in the SPS relative to hot pressing (HP). Third, we have utilized the SPS process to form transparent ceramics, porous metals and ceramics, and to effect welding of alloys.

关键词： Sintering

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On control gain selection in PI-RED

On control gain selection in PI-RED

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2006 IEEE International Conference on Networking, Sensing and Control, ICNSC'06

作者： Naixue, Xiong Xavier, Defago Yan, Yang Yanxiang, He Jing, He Asahidai Nomi Ishikawa Japan State Key Lab. of Software Engineering Computer School Wuhan University China School of Information Science Japan Advanced Institute of Science and Technology Japan School of Computer Science and Technology Wuhan University of Science and Technology Hu Bei province China State Key Lab. of Software Engineering Computer School Wuhan University Hu Bei province China Department of Computer Science Utah State University Logan UT 84322-4205 United States

ISBN: (纸本)1424400651

Active Queue Management (AQM) is an effective method used in Internet routers to enhance congestion control, and to achieve a trade off between link utilization and delay. The de facto standard, the Random Early Detection (RED) AQM scheme, and most of its variants use queue length as a congestion indicator to trigger packet dropping. Random early detection (RED) is a widely studied active queue management (AQM) scheme implemented in routers for Internet congestion control. Although certain stability conditions for various RED controllers are discussed, no efficient method for dynamically adapting control gains or result on control gain optimization has been proposed so far. Therefore based on control theory, this paper proposes Proportional and Integral RED (PI-RED) algorithm, that not only considers the average queue length at the current time slot, but also takes into consideration the past average queue lengths within a round trip time. We provides guidelines for the selection of the feedback gains (the proportional parameter and the integral parameter) for TCP/RED system to stabilize the dynamics, make the congested queue converge at a certain target and hence to improve network performance. Simulations demonstrate that indeed satisfactory performance can be achieved if the control gains are selected based on the guidelines. Based on the stability condition and control gains selection method, extensive simulations with ns2 demonstrate that indeed satisfactory performance can be achieved in terms of robustness, drop probability and stability if the control gains are selected based on the guidelines. © 2006 IEEE.

关键词： Control system analysis

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Fabrication of long period fiber gratings by carving periodic grooves on the fiber using a focused CO2 laser beam

Fabrication of long period fiber gratings by carving periodi...

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Optical Fiber Sensors, OFS 2006

作者： Wang, Yi-Ping Jin, Wei Wang, D.N. Rao, Yun-Jiang Department of Electrical Engineering The Hong Kong Polytechnic University Kowloon Hong Kong State Key Lab of Advanced Optical Communication Systems and Networks Shanghai Jiao Tong University Shanghai 200240 China School of Communication and Information Eng University of Electronic Science and Technology of China Chengdu 610054 China

Fabrication of long period fiber gratings by use of a focused CO2 laser beam to carve periodic grooves on the fibre is demonstrated. A large transmission attenuation of -47.39dB at the resonant wavelength is experimen... 详细信息

ISBN: (纸本)1557528179

关键词： Laser beams

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