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Phase-only pattern synthesis based on gradient-descent optimization

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Journal of Systems Engineering and Electronics 2016年第2期27卷 297-307页

作者： Chengjun Lu Weixing sheng Yubing Han Xiaofeng ma School of Electronic and Optical Engineering Nanjing University of Science and Technology

By applying phase-only technique in array antenna pattern synthesis, antenna arrays can form desired patterns with the use of phase shifters only. A novel phase-only pattern synthesis algorithm is proposed for the passive phased array seeker. This algorithm synthesizes the main beam of the antenna pattern through least-squares approximation, thus minimizing the errors between the actual and the desired main beams. The synthesis problem can be solved by applying gradient-descent optimization. The item for suppressing side lobes is added to the above synthesis problem. To obtain a side lobe level as low as possible, the algorithm assigns different weights to different directions in the side lobe region. The algorithm is run repeatedly and the weights are adjusted adaptively according to the normalized power in the side lobe directions. Detailed examples are presented to demonstrate the accuracy and effectiveness of the proposed approach.

关键词： pattern synthesis phase-only gradient-descent adaptively

Concurrent transmission for energy efficiency of user equipment in 5G wireless communication networks

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Science China(Information Sciences) 2016年第2期59卷 82-96页

作者： Xiao ma Min sheng Jiandong LI Qiuju YANG School of Physics and Information Technology Shaanxi Normal University State Key Laboratory of Integrated Service Networks Xidian University

In this paper, we investigate concurrent transmission among multiple radio access technologies(RATs) for energy efficiency(EE) of multi-mode user equipment(MUE) in 5G wireless communication *** both the static circuit power consumption of the MUE and channel state information of different RATs, we propose an EE maximization concurrent transmission(EXACT) strategy by fully utilizing the multiRAT combining gain of concurrent transmission. In particular, we formulate such EE maximization concurrent transmission problem as a mixed binary integer programming(MIP), and under some given static circuit power conditions, the optimal RATs selection and transmission rates for establishing concurrent transmission among multiple RATs are derived. Furthermore, in order to deal with the challenging MIP, an approximate expression is derived to simplify the integer constraints, thus the original MIP is transformed into a nonlinear continuous optimization problem. Consequently, a low complexity heuristic algorithm for general static circuit power conditions, which can achieve the near-optimal solution, is presented. Simulation results confirm the effectiveness of the EXACT strategy and show that the EE performance of the MUE can be significantly improved by reasonable and effective utilization of multiple RATs to execute concurrent transmission.

关键词： energy efficiency green communication concurrent transmission 5G wireless communication networks data splitting

On cross-correlation indicators of an S-box

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Frontiers of Computer Science 2011年第4期5卷 448-453页

作者： sheng GAO Wenping ma Zepeng ZHUO Fenghe WANG Key Laboratory of Computer Network and Information Security Ministry of Education Xidian University Xi＇an 710071 China State Key Laboratory of Integrated Service Networks Xidian University Xi＇an 710071 China

Substitution boxes （S-boxes） are often used as the most important nonlinear components in many symmetric encryption algorithms. The cryptographic properties of an S-box directly affect the security of the whole cipher system. Recently, generalized global avalanche characteristics （GGAC） were introduced to measure the correlation between two arbitrary Boolean functions. In this paper, to better evaluate the security of an S-box, we present two cross-correlation indicators for it. In addition, by studying the related properties of the cross-correlation between two balanced Boolean func- tions, we propose the lower bounds on the sum-of-squares indicator related to GGAC for two balanced functions and also for an S-box.

关键词： cryptography Boolean functions substitu-tion boxes balancedness generalized global avalanchecharacteristics cross-correlation

Air Plasma-Activated Crosslinking of Low-Density Polyethylene During Melt Mixing

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Transactions of Tianjin University 2020年第1期26卷 33-39页

作者： Yangfeng Cui Zhe ma Guiqiu ma Jing sheng School of materials Science and Engineering Tianjin Key Laboratory of Composite and Functional Materials Tianjin University

In this work,air plasma surface treatment followed by oxidation in an atmospheric environment was used to generate activated low-density polyethylene(LDPE)with oxygen-containing functional groups and peroxide *** resulting samples were then studied by using attenuated total internal reflectance-Fourier-transform infrared spectroscopy,X-ray photoelectron spectroscopy,and the 2,2-diphenyl-1-picrylhydrazyl *** radicals are generally considered active substances which can initiate the crosslinking *** mixing of the surface-treated LDPE allowed activated polymer chains with peroxide radicals to initiate the crosslinking reaction,and the maximum gel fraction obtained was 4.1%.The rheological behaviors,including viscosity,storage and loss moduli,loss tangent,and Cole-Cole plots,of the slightly crosslinked LDPE were studied,and the results of tensile experiments revealed that the formation of slightly crosslinked structures can improve yield and fracture stresses without sacrificing the breakage strain.

关键词： Air plasma Slight crosslinking Rheological behaviors Mechanical properties

Synthesis and Crystal Structure of a New Glycinato Copper Compound

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Chinese Journal of Structural Chemistry 2006年第5期25卷 631-635页

作者： XIANG sheng-chang sheng Tian-Lu FU Rui-Biao HU sheng-Min WU Xin-Tao State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter The Chinese Academy of Sciences Fuzhou Fujian 350002 China

A glycinato copper compound {Cu（NH2CH2COO）（H2O）ClO4} crystallizes in monoclinic, space group P21/n with a = 7.8299（9）, b = 10.3807（10）, c = 9.4775（12）A, β = 109.659（6）°, V = 725.43（12）A^3, Z = 4, Mr = 255.07, Dc = 2.335 g/cm^3, F（000） = 508,μ = 3.381 mm^-1, R = 0.0270 and wR = 0.0707 for 1677 observed reflections with Ⅰ 〉 2σ（Ⅰ）. The title compound contains a chain in the syn-anti conformation, which is generated by the glide-plane operation. The adjacent layers made up of the chains through the connection of perchlorate are related by inversion center operation, which links with each other through the hydrogen bonds.

关键词： glycinato copper complex chain hydrogen bonds

Preparation of Near IR Reflective materials via Hollow Ballotini Enwrapped by TiO_2

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Chinese Chemical Letters 2006年第6期17卷 829-832页

作者： Cheng Yin ma Ping sheng TANG Yan sheng LI College of Chemistry and Chemical Engineering Central South University Changsha 410083

Near IR reflective functional material was made via hollow ballotini enwrapped by TiO2 according to IR reflective principles. Metatitanic acid covers on the surface of hollow ballotini through electrostatic attraction as pH is less than 2.5. The results of SEM and XRD spectrum show that TiO2 enwraps hollow ballotini well and the crystal form is anatase. When TiO2 covering thickness is below 0.5 μm, reflectance swells along with the increase of thickness, whereas above 0.5 μm it keeps stable. Coatings made from mixing enwrapped I-IB with styrene-acrylic latex were coated on aluminum foil, and reflectances were mensurated. It is found that reflectance keeps stable when the coating can wrap the base and reflectances of the coating in visible range and in near IR range are 86% and 81%, resoectively.

关键词： Titanium dioxide hollow ballotini near IR reflective material enwrap.

Optical Tunability of Silver-Dielectric-Silver Multi-Layered Cylindrical Nanotubes Using Quasi-Static Approximation

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Chinese Physics Letters 2018年第11期35卷 28-31页

作者： Zhao-Wang Wu Ye-Wan ma Li-Hua Zhang Xun-chang Yin sheng-Bao Zhan School of Physics and Electrical Engineering Anqing Normal University

Local surface plasmon resonances（LSPRs） of silver-dielectric-silver multi-layered（SDS-ML） nanotubes are studied by theoretical calculations. Based on quasi-static approximation, the absorption cross section of SDS-ML nanotubes is plotted as a function of wavelength. The results show that SDS-ML nanotubes exhibit strong coupling between the cylindrical silver and nanotubes. The absorption spectra of LSPRs are strongly influenced by changing the radius of the inner core and outer nanotube shell. The longer wavelength is red-shifted by increasing the radius of the inner core and outer shell, while the short wavelength shows the opposite *** phenomena are explained by the plasmon hybridization theory. In addition, for clarity, the distributions of electric field intensity at their plasmon resonance wavelengths are also studied.

关键词： Silver

A case study of Asian dust storm particles:Chemical composition,reactivity to SO_2 and hygroscopic properties

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Journal of Environmental Sciences 2012年第1期24卷 62-71页

作者： Qingxin ma Yongchun Liu chang Liu Jinzhu ma Hong He Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China

Mineral dust comprises a great fraction of the global aerosol loading,but remains the largest uncertainty in predictions of the future climate due to its complexity in composition and physico-chemical *** this work,a case study characterizing Asian dust storm particles was conducted by multiple analysis methods,including SEM-EDS,XPS,FT-IR,BET,TPD/mass and Knudsen cell/*** morphology,elemental fraction,source distribution,true uptake coefficient for SO 2,and hygroscopic behavior were *** major components of Asian dust storm particles are aluminosilicate,SiO 2 and CaCO 3,with organic compounds and inorganic nitrate coated on the *** has a low reactivity towards SO 2 with a true uptake coefficient,5.767×10-6,which limits the conversion of SO 2 to sulfate during dust storm *** low reactivity also means that the heterogeneous reactions of SO 2 in both dry and humid air conditions have little effect on the hygroscopic behavior of the dust particles.

关键词： DRIFTS mineral dust SO2 reaction water adsorption

Exploring optimal combination of a file system and an I/O scheduler for underlying solid state disks

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Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第8期15卷 607-621页

作者： Hui SUN Xiao QIN chang-sheng XIE National Laboratory for Optoelectronics and School of Science and Technology Huazhong University of Science and Technology Department of Computer Science and Software Engineering Auburn University

Performance and energy consumption of a solid state disk(SSD) highly depend on file systems and I/O schedulers in operating systems. To find an optimal combination of a file system and an I/O scheduler for SSDs, we use a metric called the aggregative indicator(AI), which is the ratio of SSD performance value(e.g., data transfer rate in MB/s or throughput in IOPS) to that of energy consumption for an SSD. This metric aims to evaluate SSD performance per energy consumption and to study the SSD which delivers high performance at low energy consumption in a combination of a file system and an I/O scheduler. We also propose a metric called Cemp to study the changes of energy consumption and mean performance for an Intel SSD(SSD-I) when it provides the largest AI, lowest power, and highest performance, respectively. Using Cemp, we attempt to find the combination of a file system and an I/O scheduler to make SSD-I deliver a smooth change in energy consumption. We employ Filebench as a workload generator to simulate a wide range of workloads(i.e., varmail, fileserver, and webserver), and explore optimal combinations of file systems and I/O schedulers(i.e., optimal values of AI) for tested SSDs under different workloads. Experimental results reveal that the proposed aggregative indicator is comprehensive for exploring the optimal combination of a file system and an I/O scheduler for SSDs, compared with an individual metric.

关键词： Solid state disk(SSD) Performance Energy consumption File system I/O scheduler