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Time-domain training sequences design for MIMO OFDM channel estimation

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第4期9卷 464-469页

作者： Zhen LU jian-hua GE Department of Electronic Engineering Shanghai Jiao Tong Universiry Shanghai 200240 China Department of Communications Engineering Xidian University Xi＇an 710071 China

This paper describes a Least Squares (LS) channel estimation scheme for MIMO OFDM systems based on time-domain training sequence. We first compute the minimum mean square error (MSE) of the LS channel estimation, and then derive the optimal criteria of the training sequence with respect to the minimum MSE. It is shown that optimal time-domain training sequence should satisfy two criteria. First, the autocorrelation of the sequence transmitted from the same antenna is an impulse function in a region longer than the channel maximum delay. Second, the cross-correlation between sequences transmitted from different antennas is zero in this region. Simulation results show that the estimator using optimal time-domain training sequences has better performance than that using optimal frequency training sequence at low signal-to-noise ratio (SNR). To reduce the training overhead, a suboptimal training sequence is also proposed. Comparing with optimal training sequence, it has low computation complexity and high transmission efficiency at the expense of little performance degradation.

关键词： MIMO OFDM Channel estimation Time-domain training sequence

BREAKING THE MONOLITH： STRATEGY, VARIETY, AND PERFORMANCE OF ENTERPRISE INFORMATION SYSTEMS

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Journal of Systems Science and Systems Engineering 2018年第6期27卷 727-770页

作者： Yuanxun gu Lian Qi jian Wang School of Economics and Management Beijing Jiaotong University Beijing 100044 China Rutgers Business School Rutgers the State University of New Jersey Newark 07102 USA School of Managernent Shanghai University Shanghai 200444 China

This paper intends to understand the form of implementations of Enterprise Information Systems （EISs）. EISs are usually provided as packaged software products. Due to the diversities of implementations, EISs are often characterized by their system architectures. A conceptual framework is proposed to delineate the diversity and dynamics of EIS implementations. This framework is constituted of three components, EIS strategy, variety, and process-level performance （SVP）. In particular, the variety of implementations is defined by two constructs, application scope and application depth. A Partial Least Squares structural equation modeling approach is applied to test the hypotheses according to the survey data from 223 project reports of EIS implementations in China. The results show that the EIS strategy and variety can both affect the performance of the implemented EISs. Specifically, application depth has an important mediating effect on the relationship between EIS strategy and performance. EIS strategy and application depth are breakthrough points to improve the performance of the implemented EISs. These findings suggest that the variety plays a central and effective role in the analysis of EIS implementations. This SVP framework highlights the interconnections among its components and captures the form of EIS implementations.

关键词： EIS strategy application scope application depth process-level performance

Collective Hamiltonian for Multi-O（4） Model

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Communications in Theoretical Physics 2007年第2期47卷 309-316页

作者： gu jian-Zhong Masato Kobayasi China Institute of Atomic Energy P.O. Box 275 （18） Beijing 102413 China Department of Physics Graduate School of Science Kyoto University Kyoto 606-8502 Japan Yukawa Institute for Theoretical Physics Kyoto University Kyoto 606-8502 Japan

The collective Bamiltonian up to the fourth order for multi-O（4） model is derived based on the self-consistent collective-coordinate （SCC） method, which is formulated in the framework of the time-dependent Hartree-Bogoliubov （TDHB） theory. The validity of the collective Hamiltonian is checked in the two special cases of the multi-O（4） model： the case where the number of the shells is equal to one （a single j-shell case）, and the case where the Hartree-Bogoliubov equilibrium point is spherical （the spherical case）. The collective Hamiltonian constitutes a good starting point to study nuclear shape coexistence.

关键词： self-consistent collective-coordinate method multi-O(4) model time-dependent Hartree-Bogoliubov theory collective Hamiltonian

Vibrational Resonance in Fractional-Order Anharmonic Oscillators

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Chinese Physics Letters 2012年第10期29卷 97-100页

作者： YANG jian-hua School of Mechanical and Electrical Engineering China University of Mining and TechnologyXuzhou 221116

The phenomenon of vibrational resonance in fractional-order anharmonic oscillators is *** on the method of separating slow and fast motions,the approximate solution of the response amplitude is *** analytical and numerical results show that not only the high-frequency signal but also the fractional-order damping can induce vibrational *** present results provide a new way to control periodical signals in coupled systems.

关键词： harmonic vibrational fractional

Affinity Adsorption of Bilirubin on Cibacron Blue F3GA-modified Microporous Polytetrafluoroethylene Capillary

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Chemical Research in Chinese Universities 2010年第2期26卷 323-330页

作者： JIN gu YAO jian-xia Department of Chemistry University of Science and Technology of China Hefei 230026 P. R. China

Bilirubin removal from human plasma was obtained via an affinity microporous polytetrafluoroethylene（MPTFE） capillary. The new adsorbent comprised grafted glycidyl methacrylate（GMA） via radiation-induced polymerization as hydrophilic coating and reactive sites; ethylenediamine（EDA） as a spacer arm; Cibacron Blue F3GA（CB F3GA） as an affinity ligand; MPTFE capillary as the supporting matrix. The average density of CB F3GA attachment to MPTFE capillaries was found to be 136.5 μmol/g. The capacity of bilirubin adsorbed on affinity MPTFE capillaries is 76.1 mg bilirubin/g polymer（at 25℃）. This new adsorbent has advantages over both membrane and traditional micro-column, and this system is stable and easy to operate. The results of blood tests suggest the CB F3GA affinity capillary has good blood compatibility.

关键词： Bilirubin removal Radiation grafting Cibacron Blue F3GA Polytetrafluoroethylene Microporous capillary

EXPERIMENTS OF THREE-DIMENSIONAL FLOW STRUCTURE IN BRAIDED RIVERS

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Journal of Hydrodynamics 2009年第2期21卷 228-237页

作者： hua Zu-lin gu Li CHU Ke-jian Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education College of Environmental Science and Engineering Hohai University Nanjing 210098 China State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University Nanjing210098 China

The braided river is a typical river pattern in nature, but there is a paucity of comprehensive data set describing the three-dimensional flow field in the braided river. A physical model experiment was used to study the flow characteristics in the typical braided river with a mid-bar between two anabranches. In the experiment, two kinds of mid-bar with the ratios of its length to maximal width of 3 and 5 were considered. Moreover, the mid-bar could be moved to adjust the width of two anabranches. The detailed measurements of velocity were conducted using an acoustic Doppler velocimeter over a grid defined throughout the whole braided river region, including the bifurcation, two anabranches and the confluence. In two kinds of mid-bar braided models, a separation zone was observed in the anabranch of the model in which the ratio of length to maximal width of mid-bar is 3, however the separation zone was not found in another model in which the ratio is 5. In addition, the opposite secondary cells were observed at the bend apex of anabranch in two models, and different longitudinal velocity distributions in the entrance region of anabranch account for this opposite flow structure. Finally, turbulent kinetic energy were shown and compared in different situations. The high turbulence occurs at the place with strong shear, especially at the boundary of the separation zone and the high velocity passing flow.

关键词： braided river three-dimensional flow structure secondary flow turbulent kinetic energy

The composite X-ray spectra of radio-loud and radio-quiet SDSS quasars

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Research in Astronomy and Astrophysics 2021年第1期21卷 33-44页

作者： Min-hua Zhou Min-Feng gu Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical ObservatoryChinese Academy ofSciences80 Nandan RoadShanghai 200030China University of Chinese Academy of Sciences 19A Yuquan RoadBeijing 100049China

We present a study of the X-ray emission for a sample of radio-detected quasars constructed from the cross-matches between SDSS,FIRST catalogs and XMM-Newton archives.A sample of radio-quiet SDSS quasars without FIRST radio detection is also assembled for *** construct the optical and X-ray composite spectra normalized at rest frame 4215 A(or 2200 A)for both radio-loud quasars(RLQs)and radio-quiet quasars(RQQs)at z≤3.2,with matched X-ray completeness of 19%,redshift and optical *** the optical composite spectrum of RLQs is similar to that of RQQs,we find that RLQs have a higher X-ray composite spectrum than RQQs,consistent with previous studies in the *** dividing the radio-detected quasars into radio loudness bins,we find the X-ray composite spectra are generally higher with increasing radio ***,a significant correlation is found between the optical-to-X-ray spectral index and radio loudness,and there is a unified multi-correlation between the radio and X-ray luminosities and radio loudness in radio-detected *** results could be possibly explained with the corona-jet model,in which the corona and jet are directly related.

关键词： methods:statistical catalogs quasars:general X-rays:general

New Active Organic Substance in Oyster Shell Capable of Scavenging Oxygen Free Radicals with High Efficiency

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Chemical Research in Chinese Universities 2008年第2期24卷 171-174页

作者： MA jian-hua College of Biology Engineering Jimei University Xiamen 361021 P. R. China

A light purple organic active substance capable of scavenging hydroxyl radical（OH） with a high efficiency was extracted from Oyster shell at an extraction rate of 2.49%. It was found for the first time that this active substance may scavenge OH with the efficiency far higher than that of vitamin C. This active substance may scavenge also superoxide radical（O2） although the scavenging efficiency is far lower than that of vitamin C. Infrared spectrometry and routine chemical analysis primarily reveal that this active substance belongs to glycoprotein.

关键词： Oyster shell Glycoprotein Scavenging Hydroxyl radical Superoxide radical

Mn evaporation and denitrification behaviors of molten Mn steel in the vacuum refining with slag process

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International Journal of Minerals,Metallurgy and Materials 2021年第8期28卷 1288-1297页

作者： jian-hua Chu Yan-ping Bao State Key Lab of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

Considering the precise composition control on the vacuum refining of high-Mn steel, the behaviors of both Mn evaporation and nitrogen removal from molten Mn steel were investigated via vacuum slag refining in a vacuum induction furnace. It was found that the reaction interfaces of denitrification and Mn evaporation tend to migrate from the surface of slag layer to the surface of molten steel with the gradual exposure of molten steel during the vacuum slag refining process. Significantly, compared with the experimental group without slag addition, the addition of slag into steel can result in a lower Mn evaporation rate constant of 0.0192 cm·min~(-1) at 370 Pa, while the denitrification rate is almost not affected. Besides, the slag has a stronger inhibitory effect on Mn evaporation than the reduced vacuum pressure. Moreover, the inhibitory effect of the slag layer on Mn evaporation can be weakened with the increase of the initial Mn content in molten steel. The slag layer can work as an inhibitory layer to reduce the Mn evaporation from molten steel, the evaporation reaction of Mn mainly proceeds on the surface of the molten steel. This may be attributed to the Mn mass transfer coefficient for one of reaction at steel/slag interface, mass transfer in molten slag, and evaporation reaction at slag/gas interface is lower than that of evaporation reaction at steel/gas interface. The introduction of slag is proposed for both denitrification and manganese control during the vacuum refining process of Mn steels.

关键词： manganese evaporation denitrification vacuum slag evaporation rate