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Systematic energy-balanced cooperative transmission scheme in wireless sensor networks

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The Journal of China Universities of Posts and Telecommunications 2012年第6期19卷 14-18页

作者： yao li-ping li Xi JI Hong XU Quan-sheng School of Telecommunication Engineering Beijing University of Posts and Telecommunications

Energy efficiency is a critical issue in wireless sensor networks （WSNs）. In order to minimize energy consumption and balance energy dissipation throughout the whole network, a systematic energy-balanced cooperative transmission scheme in WSNs is proposed in this paper. This scheme studies energy efficiency in systematic view. For three main steps, namely nodes clustering, data aggregation and cooperative transmission, corresponding measures are put forward to save energy. These measures are well designed and tightly coupled to achieve optimal performance. A half-controlled dynamic clustering method is proposed to avoid concentrated distribution of cluster heads caused by selecting cluster heads randomly and to get high spatial correlation between cluster nodes. Based on clusters built, data aggregation, with the adoption of dynamic data compression, is performed by cluster heads to get better use of data correlation. Cooperative multiple input multiple output （CMIMO） with an energy-balanced cooperative cluster heads selection method is proposed to transmit data to sink node. System model of this scheme is also given in this paper. And simulation results show that, compared with other traditional schemes, the proposed scheme can efficiently distribute the energy dissipation evenly throughout the network and achieve higher energy efficiency, which leads to longer network lifetime span. By adopting orthogonal space time block code （STBC）, the optimal number of the cooperative transmission nodes varying with the percentage of cluster heads is also concluded, which can help to improve energy efficiency by choosing the optimal number of cooperative nodes and making the most use of CMIMO.

关键词： energy efficiency dynamic clustering cooperative MIMO data aggregation wireless sensor networks

Resource allocation algorithm in LTE uplink SC-FDMA system for time-varying channel with imperfect channel state information

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The Journal of China Universities of Posts and Telecommunications 2013年第2期20卷 7-11页

作者： XU Quan-sheng li Xi JI Hong yao li-ping Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications

In long term evolution （LTE） uplink single carrier frequency division multiple access （SC-FDMA） system, the restriction that multiple resource blocks （RBs） allocated to a user should be adjacent, makes the resource allocation problem hard to solve. Moreover, with the practical constraint that perfect channel state information （CSI） cannot be obtained in time-varying channel, the resource allocation problem will become more difficult. In this paper, an efficient resource allocation algorithm is proposed in LTE uplink SC-FDMA system with imperfect CSI assumption. Firstly, the resource allocation problem is formulated as a mixed integer programming problem. Then an efficient algorithm based on discrete stochastic optimization is proposed to solve the problem. Finally, simulation results show that the proposed algorithm has desirable system performance.

关键词： SC-FDMA resource allocation imperfect channel state information discrete stochastic optimization time-varying channel

A Corpus-based Approach to English Subordinate Clause Identification

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High Technology Letters 2001年第1期7卷 10-12页

作者：张晶 Zhao Tiejun li sheng yao Jianmin Department of Computer Science and Engineering Harbin Institute of Technology

The complex sentence structure of English is a bottleneck to our practical machine translation system. The simplification of English subordinate clauses will greatly relieves the burden of parsing and other grammatical or semantic analysis of a complex sentence, thus improves the output quality of the MT system. But there have not any satisfactory research achievements reported in this field up to now as we know. In this paper, author’s work on a corpus-based approach to English subordinate clause identification is reported. The approach integrates rule-based and statistical methods to get the left and right boundaries of the subordinate clauses. The Penn Treebank corpus is used as the training standard. The precision and recall ratios of subordinate clause identification are tested on both closed and open corpora. A result of 92.9% precision and 91.26% recall is obtained for the closed test and the open test result is 80.34% precision and 83.93% recall. This algorithm has been integrated into our machine translation system. The method can also be applied to processing of any other language.

关键词： Subordinate clauses Corpus Knowledge acquisition

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江苏沿海地区杂交与常规油菜主要性状分析

上海农业学报 2008年第2期24卷 65-68页

作者：单忠德姚立生孙明法孙红芹万林生江苏沿海地区农业科学研究所盐城224002

采用多变数分析方法,对沿海地区杂交与常规油菜品种的性状资料进行统计分析表明,该地区种植的杂交与常规品种存在较大的差异。回归分析表明,不同性状在两种不同类型油菜产量上所起的作用也不相同:对杂交油菜产量贡献较大的性状是每角粒... 详细信息

采用多变数分析方法,对沿海地区杂交与常规油菜品种的性状资料进行统计分析表明,该地区种植的杂交与常规品种存在较大的差异。回归分析表明,不同性状在两种不同类型油菜产量上所起的作用也不相同:对杂交油菜产量贡献较大的性状是每角粒数;一次分枝结角数对常规品种产量起显著作用。

关键词：常规油菜杂交油菜植株性状统计分析

Wear and corrosion resistance of laser-cladded Fe-based composite coatings on AISI 4130 steel

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International Journal of Minerals,Metallurgy and Materials 2018年第6期25卷 716-728页

作者： li Fan Hai-yan Chen yao-hua Dong li-hua Dong Yan-sheng Yin College of Ocean Science and Engineering Shanghai Maritime University Department of Marine Engineering Nantong Shipping College School of Mechanical Engineering Shanghai Jiaotong University

The wear and corrosion resistance of Fe_（72.2）Cr_（16.8）Ni_（7.3）Mo_（1.6）Mn_（0.7）C_（0.2）Si_（1.2） and Fe_（77.3）Cr_（15.8）Ni_（3.9）Mo_（1.1）Mn_（0.5）C_（0.2）Si_（1.2） coatings laser-cladded on AISI 4130 steel were *** coatings possess excellent wear and corrosion resistance despite the absence of expensive yttrium,tungsten,and cobalt and very little *** microstructure mainly consists of dendrites and eutectic phases,such as duplex（γ＋α）-Fe and the Fe–Cr（Ni）solid solution,confirmed via energy dispersive spectrometry and X-ray *** cladded Fe-based coatings have lower coefficients of friction,and narrower and shallower wear tracks than the substrate without the cladding,and the main wear mechanism is mild abrasive *** test results suggest that the soft Fe_（72.2）Cr_（16.8）Ni_（7.3）Mo_（1.6）Mn_（0.7）C_（0.2）Si_（1.2） coating with high Cr and Ni concentrations has high passivation resistance,low corrosion current,and positive corrosion potential,providing a better protective barrier layer to the AISI 4130 steel against corrosion.

关键词： Fe-based coating laser cladding AISI 4130 steel wear resistance corrosion resistance

甘蓝型黄籽油菜细胞质雄性不育系盐2A的选育与研究

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种子 2007年第5期26卷 94-96页

作者：单忠德姚立生严国红孙红芹孙明法王爱民江苏沿海地区农科所江苏盐城224002

应用品种间杂交,将优质黄籽品系D 180-1的黄籽性状导入细胞质雄性不育保持系盐1 B及其不育系盐1 A,育成了甘蓝型黄籽油菜细胞质雄性不育系盐2 A和保持系盐2 B。盐2 A黄籽株率91.0%,黄籽度3.93,含油率44.5%,不育性彻底,品质双低。与黑籽... 详细信息

应用品种间杂交,将优质黄籽品系D 180-1的黄籽性状导入细胞质雄性不育保持系盐1 B及其不育系盐1 A,育成了甘蓝型黄籽油菜细胞质雄性不育系盐2 A和保持系盐2 B。盐2 A黄籽株率91.0%,黄籽度3.93,含油率44.5%,不育性彻底,品质双低。与黑籽恢复系及黄籽恢复系材料配组,可选择到强优势组合。

关键词：甘蓝型黄籽油菜细胞质雄性不育系盐2A 选育研究

Interfacial engineering for efficient and stable two-terminal perovskite-based tandem solar cells

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Rare Metals 2024年第11期43卷 5573-5624页

作者： Ying li Di-sheng yao Fei Long Guo-Zhen Zhang Feng Yu Guangxi Key Laboratory of Optical and Electronic Material and Devices School of Materials Science and EngineeringGuilin University of TechnologyGuilin 541004China Guangxi Key Laboratory of Optical and Electronic Material and Devices School of Materials Science and EngineeringCollaborative Innovation Center for Exploration of Nonferrous Metal Deposits and Efficient Utilization of ResourcesGuilin University of TechnologyGuilin 541004China School of Chemistry and Materials Science Nanjing University of Information Science and TechnologyNanjing 210044China

Two-terminal(2T)tandem solar cells(TSCs)are optically and electrically connected by two subcells with complementary bandgaps,which are designed to overcome the Shockley-Queisser(S-Q)limit of singlejunction solar ***-inorganic hybrid perovskites are ideal light-absorbing materials for 2T TSCs due to their tunable bandgaps,low-temperature solution-based processing,and excellent light absorption ***,2T perovskite-based TSCs(PTSCs)have aroused widespread interest among the photovoltaic *** present,the key to obtaining efficient and stable 2T PTSCs is establishing efficient interfaces and layers with good photoelectric properties and high compatibility of *** particular,interfacial engineering based on effective recombination layers(RCLs)and buffers has a prominent effect on achieving enhanced power conversion efficiency(PCE)of 2T PTSCs with improved operational *** this article,the current frontier issues of 2T PTSCs including different device structures and properties are reviewed in detail to analyze their merits,demerits and solutions to overcome ***,the component engineering,interface engineering and theoretical PCE analysis for designing 2T PTSCs proposed by material simulations are ***,the scalability of interfacial passivation from single-junction perovskite solar cells to 2T PTSCs is evaluated,and the function mechanisms of RCLs and buffers are also summarized and analyzed ***,the challenges faced by 2T PTSCs are pointed out,and their developme nt directions are *** article aims to provide viable guidance for realizing practical manufacturing technologies for the commercialization of 2T PTSCs.

关键词： Two-terminal tandem solar cells Organic-inorganic perovskites Passivation interfaces Recombination layers and buffers Efficiency and stability

Lanthanide Thiolate Complexes： Novel Initiators for Ring-opening Polymerization of ε-Caprolactone

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Chinese Journal of Chemistry 2005年第11期23卷 1541-1544页

作者： SUN, Hong-Mei li, Huan-Rong yao, Chang-sheng yao, Ying-Ming sheng, Hong-Ting SHEN, Qi The Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry and Chemical Engineering Suzhou University Suzhou 215006 China

The ring-opening polymerization （ROP） of ε-caprolactone （ε-CL） using lanthanide thiolate complexes [（CH3CsH4）2Sm（μ-SPh）（THF）]2 （1） and Sm（SPh）3（HMPA）3 （2） as initiators has been investigated for the first time. Both of 1 and 2 were found to be highly efficient initiators for the ROP of ε-CL. The poly（ε-caprolactone）（PCL） with molecular weight Mn up to 1.97 ×10^5 and relatively narrow molecular weight distributions （1.20〈MW/Mn〈 2.00） have been obtained in high yield in the temperature range of 35-65℃. According to the polymer yield, 2 showed much higher activity than 1. However, the number-average molecular weight of PCL obtained with 2 was much lower than with 1. The possible polymerization mechanism of the ε-CL polymerization has been proposed based on the results of the end group analysis of the ε-CL oligomer.

关键词： ring-opening polymedzation samarium thiolate complex catalysis ε-caprolactone

Drinking water production by uitrafiltration of Songhuajiang River with PAC adsorption

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Journal of Environmental Sciences 2007年第5期19卷 536-539页

作者： XIA sheng-ji liU Ya-nane li Xing yao Juan-juan State Key laboratory of Pollution Control and Resources Reuse Tongji University Shanghai 200092 China School of Environmental Science and Engineering Dong Hua UniversityShanghai 201620China School of Architecture and Civil Engineering Beijing University of Technology Bejing 100083 China

In recent years, membrane ultrafiltration （UF） of surface water for drinking water treatment has become a more attractive technology worldwide as a possible alternative treatment to conventional clarification. To evaluate the performance of ultrafiltration membranes for treatment of surface water in North China, a 48-m^2 low pressure hollow fiber membrane ultrafiltration pilot plant was constructed. Ultrafiltration was operated in cross-flow and with powdered activated carbon （PAC） adsorption. Turbidity was almost completely removed to less than 0.2 NTU （below Chinese standard 1 NTU）. It was found that PAC addition enhanced organic matter removal. The combined process of PAC/UF allowed to 41% removal of CODMn, 46% removal of DOC and 57% decrease in UV254 absorbance. The elimination of particles, from average 12000/ml in the raw water to approximately 15/ml in the permeated, was observed. When PAC concentration was below 30 mg/L, backwashing could recovery the membrane flux with backwash interval/backwashing duration of 1/30.

关键词： surface water drinking water treatment ultrafiltration powdered activated carbon