Research on the improvement of the convergencespeed for CDMA system power control

Optimal power control with game-theory has been a hot research topic in code division multiple access (CDMA) system. However, the convergence speed of the power control algorithm based on traditional static game-theory is not fast enough and the power fluctuation is large during the iterative process. In order to solve this problem, dynamic game-theory is introduced into CDMA system power control algorithm. The simulation results show that the proposed algorithm, compared with the distributed power control algorithm based on the traditional static game theory, can improve the convergence speed obviously with the same power spending.     

Multi-Step Iterative MUD Technology for TD-SCDMA System

Joint Detection technology is a hot point in the research of TD-SCDMA system. Because of a SNR degradation, JD can not reach the need of system performance when system loads is close to the spread factor. MSJD and iterative multi-user detection are put forth to overcome the problem. When iterative MUD is adopted, the research shows that system performance is close to single user performance after 3 iterations, but its computational complexity grows exponentially with the number of code channel. When MSJD is adopted, complexity is reduced compared with iterative MUD, but system performance of code channels numbered K is only close to system performance of code channels numbered K/2 as JD is used. Considering computational complexity and system performance, multi-step iterative multi-user detection technology is brought forth based on iterative MUD and MSJD. According to simulation, the result can be concluded that complexity is reduced compared with single iterative MUD and system performance is improved compared with single MSJD.     

Group based DBF MUD in CDMA mobile communication system

For the CDMA wireless cellular communication system, a new methodology is proposed to combine digital beamforming (DBF) with multi user detection (MUD) technology which harnesses the co channel interference mitigation and obtains better performance. The proposed approach assigns all the users within a cell into separated groups according to their direction of arrival (DOA). Then, only one DBF branch is employed for a singular group so that the main lobe is steered to the desired users in the group and nulls are directed to the mobile stations in other group. Furthermore, inter group interference is degraded by MUD following the DBF. The new strategy simplifies the weight vector calculation and solves the unorthogonal channel problem. Additionally, it decreases the bit error rate. The analysis and simulation illustrate the fruits of the new mechanism.     

Study of Acquisition in a Rake Receiver Based on Digital Matched-filter

The Rake receiver based on digital matched filter(DMF) is studied extensively in order to investigate the performance of the PN code acquisition.By using the state transition diagram,the authors derive the analytic expressions of the mean acquisition time of the Rake receiver based on DMF over frequency-selective channel.Numerical analysis is also given.It is shown that the proposed Rake receiver based on DMF can accelerate the process of PN code acquisition.Because there are many resolved multipath components over frequency-selective channel,the detection probability of Rake receiver is larger than the conventional receiver.If more fingers of Rake receiver are available,then the mean acquisition time is longer and the threshold of detector can be set more widely.     

Framework design of multimedia data parallel management in the informatization of rural areas

In order to realize the efficient transmission and analysis of multimedia data under TD-SCDMA network, a parallel management framework is proposed. This framework improves the general framework for data management by parallelizing the generation of standardized data and the analysis of original data. It not only reduces the data volume in transmission and analysis, but also fits for parallel optimization. Focusing on image analysis in the informatization of rural areas, the authors introduce the procedures to realize the parallel management framework. As can be seen from experiment results, the data volume of image data is reduced to 1/12 after parallel optimization, and the time cost of analysis is substantially reduced. Thus, it can effectively relax the requirement of the TD-WCDMA transmission bandwidth for multimedia application in the informatization of rural areas.     

K肥对假俭草种子生产能力的影响

试验以优良的峨眉假俭草种质资源为材料,通过施不同浓度的K肥,测定分析K肥对假俭草种子生产能力的影响.结果表明分两次施用7.5 g·m-2K2O处理效果最佳,使生殖枝出现较集中、生殖枝数增加了22%,使花序长度、小穗数分别增加了4.36%、17%,提高了假俭草潜在种子产量.同时结实率增加了16%,种子的千粒重和生活力都有明显的增加,提高了假俭草种子产量与质量.     

中国丝绸产业国际竞争力研究

采用显示性竞争优势指数法(Competitive Advantage, CA),结合翔实的数据,对中国丝绸产业的国际竞争力进行较为全面的实证分析,分析结果表明中国的丝绸国际竞争力呈直线下降的趋势。笔者认为影响中国丝绸产业国际竞争力的主要因素为：（1）产品质量与世界先进水平仍然存在着较大的差距;（2）中国的茧丝绸管理体制不适应市场经济的要求,严重的阻碍了中国丝绸国际竞争力的发展;（3）行业法规迟迟不能出台,宏观调控能力乏力;（4）中国的品牌效应在中国仍然没有真正形成;等。笔者还进一步就提高中国丝绸产业的国际竞争力的提出自己的建议：（1）改革和理顺宏观管理体制;（2）加快茧丝绸行业法规制定,加强行业管理的权威性,加大宏观调控的力度;（3）加大中国的科技投入,争取实现各项关键技术的重大突破;（4）进一步巩固“东桑西移”产业布局调整的成果,加快促进产业升级和技术进步;（5）加大对丝绸产品的宣传力度,尽快开发中国的丝绸市场;（6）进一步宣传和实施中国的高档丝绸标志的品牌战略,提高中国丝绸品牌的知名度。     

A Data Detector Based on Channel Equalizer Designed for the Downlink of CDMA Systems

In code-division multiple-access (CDMA) systems,sub-optimum multi-user or joint detection algorithms have been studied recently, which are mostly designed for the uplink situation. The algorithms are too complex to implement for the downlink situation. The conventional receiver consisting of matched filters is often inefficient in eliminating MAI. The authors propose a data detection algorithm designed for downlink of CDMA systems which introduce channel equalization to eliminate MAI. It consists of a channel equalizer and code matched filter. The equalization algorithm is based on zero forcing (ZF) criterion.The performance of the algorithm is better than metched filter's and its complexity is cower than tunt of sub-optimum multi-user detection.     

套袋对苹果果实表皮组织抗氧化特性的影响

树冠不同方位果实由于所处的微域环境不同,抗氧化特性有很大差异。生长季晴天,无论套袋与否,均以树冠西南面果实氧化胁迫程度最重。其中,O2^-含量相当于树冠其他方位1．23～1．37倍;MDA含量相当于树冠其他方位1．32～1．75倍;SOD活性相当于树冠其他方位1．40～1．69倍。一般情况下,套袋后致使果实经受的环境胁迫程度加大,因而果皮组织中O2^-和MDA含量以及SOD活性都高于不套袋处理。由于套袋果实长期经受高温、弱光微域环境的驯化,除袋后果实对外界环境条件的剧烈变化较为敏感。表现为果皮组织O2^-含量增加,SOD活性明显提高,表明果实中迅速启动了环境胁迫下的应急反应。     

套袋对苹果果实表皮组织抗氧化特性的影响

树冠不同方位果实由于所处的微域环境不同,抗氧化特性有很大差异。生长季晴天,无论套袋与否,均以树冠西南面果实氧化胁迫程度最重。其中,O2^-·含量相当于树冠其他方位1.23-1.37倍;MDA含量相当于树冠其他方位1.32-1.75倍;SOD活性相当于树冠其他方位1.40-1.69倍。一般情况下,套袋后致使果实经受的环境胁迫程度加大,因而果皮组织中O2^-·和MDA含量以及SOD活性都高于不套袋处理。由于套袋果实长期经受高温、弱光微域环境的驯化,除袋后果实对外界环境条件的剧烈变化较为敏感。表现为果皮组织O2^-·含量增加,SOD活性明显提高,表明果实中迅速启动了环境胁迫下的应急反应。     

鸡胸肉蒸煮失水率影响的研究

研究几种盐对鸡胸肉蒸煮失水率的影响,在此基础上进行了正交实验,影响鸡胸肉蒸煮失水率的显著因素为柠檬酸钠和三聚磷酸钠。验证实验表明,最佳复合配比可使鸡胸肉的蒸煮失水率比对照降低20%。     

Safeguarding Capability Index System of Regional Sustainable Development

According to the new requirement of sustainable development in the new stage, this paper puts forward the definition of the safeguarding capacity of regional sustainable development and uses some statistical methods of frequency statistics and principal component analysis to construct the index system of safeguarding capacity. Then it takes the data of the Three Gorges reservoir area for example to make empirical analysis, and provides efficient measurement tools to further measure the regional sustainability together with its safeguarding capacity, and therefore helps the government and the relevant organizations to establish more scientific policies of sustainable development.     

Web System Development Model Based on Access Security MVC

In order to reduce the inconvenience of maintainability and reusability of web application system based on MVC, which is brought by the code of access security and coupling tightly with other modules, A web system development model based on access security MVC is put forward. The main framework and running process are provided and the key techniques of this model are researched. The model is applied to the practical development of the network distribution management system.     

农业科研机构科技创新能力评价平台设计与实现

为给科研机构创新能力评价决策者提供一个科学、便捷的软件工具,研究立足系统科学和管理科学理论,分析了农业科技创新过程,构建了适合农业科研机构的指标评价体系和模型,并研发了基于多源数据的农业科技创新评价分析平台。然后利用该平台将评价指标体系应用于国家级农业科研机构的评价,并根据评价结果将科研机构划分为科技创新型、科学创新型、技术创新型、经营主导型、基础实力型、相对劣势型,并针对每种类型提出了相应的管理措施。     

Influence of HVDC System on the Shaft of Hydro-generator Unit

Widely concerns of the influence of the HVDC system on the Three Gorges power station have been shown so far. Based on the understanding of the mechanism of the non-characteristic harmonics introduced by HVDC system, the influence of interharmonics on the shaft of hydro-generator unit is studied. A MATLAB simulation model for the Three Gorges hybrid AC and DC transmission system with considering the effect of generator-unit shaft is established. Through time-domain simulation, the influence of the minor-associated component of interharmonics on the generator-unit shaft is analyzed, which arise from the asynchronous operation of the HVDC system. Also, the complex torque coefficient method in frequency-domain is used to analyze this problem. Same conclusions can be drawn from the results of timedomain and frequency-domain analyses.     

一株灰潮土解磷菌的解磷特性及其对花生的促生作用

为研究解磷菌能使土壤中被铁、铝等吸附固定的难溶性的非有效态磷转化为易于被植物吸收利用的有效态磷,促进农作物的生长。从南京长江南岸的潮土中分离筛选获得了一株解磷效果好、性状稳定的解磷细菌Y1。观测了菌株Y1形态及生理生化性状,测定其16S rDNA的保守序列。通过菌株生长和发酵条件试验,研究了该菌株在不同培养条件下的解磷能力。通过设置盆栽实验,研究了Y1菌株对花生生长的作用。实验结果初步确定菌株Y1为荧光假单胞菌(Pseudomonas fluorescens),该菌株在碳源为葡萄糖、氮源为硝酸铵、初始pH 6~8、装液量为50/250 mL时,解磷效果最好。盆栽试验结果表明,接种菌株Y1的花生根长、根表面积、根直径分别比对照增加159.0%、133.0%、18.9%,植株对N、P、K的吸收量分别比对照高73.6%、26.6%、41.0%,差异均达显著水平。本实验从灰潮土中筛选出一株高效解磷菌Y1,不仅能够促进花生的生长、产量,而且能够增加花生植株对N、P、K的吸收。该研究结果为菌株Y1在农业生产中的应用提供了理论依据和实验基础。     

Influence of Steam Turbine System on Low Frequency Oscillation

Low frequency oscillation of electric power system is a problem which electric workers always care about. The influences of prime mover characteristics were ignored in the past research. The paper introduces the models of steam turbine system and each part of electric power system, and calculates the corresponding eigenvalues, then analyzes the influences of steam turbine system on low frequency oscillation.     

基于因子聚类分析的区域农产品物流能力评价——以河北省为例

本文应用因子分析和聚类分析法,结合统计数据,以河北省11市的统计数据为样本数据,通过SPSS16.0软件对电子商务环境下区域农产品物流能力进行实证研究,得出了各市的农产品物流能力得分排名,并依此进行了聚类分析,提出了河北省农产品物流中心规划建议。结果表明,在分析区域农产品物流能力过程中运用因子聚类分析法,所得结论客观、可信、较有说服力,为区域物流规划提供了重要参考和依据。该方法对其他区域物流规划也有较好的借鉴作用。     

稻田耕作制度对CH4气体排放影响的研究进展

甲烷是重要的温室气体,其辐射增温效应是CO2的20~30倍。稻田是CH4的重要排放源之一。稻田CH4的排放是稻田CH4产生、氧化和传输综合作用的结果。影响稻田CH4释放的因素众多。本研究从水稻的农耕制度角度总结近年来关于稻田CH4排放的影响因素的研究,系统地归纳了水稻生物学特性、品种栽种方式、水肥管理等方面对CH4气体排放影响,同时从耕作角度提出了稻田CH4减排的技术措施。