118 research outputs found
The Performance Simulation of Turbo Code in Shallow Water Acoustic Communication
海洋是21世纪人类社会可持续发展的宝贵财富和最后空间,水声通信与国防军事保障、海洋环境监测和科学考查、海洋渔业、海洋矿产开发等都有密切联系,具有重要的军事和民用意义。由于声波是目前水下通信最为有效的载体,因此水声通信成为目前水下无线通信最有效的技术手段。 水声信道是迄今为止最为复杂的无线通信信道之一,其固有的时-空-频变以及窄带、高噪、强多途干扰、传输时延大等信道特征,给水声通信的有效性和可靠性带来巨大的挑战。要实现有效可靠的信息传输性能,信道纠错码是一项关键技术。Turbo码近年来成为信息论和编码界研究的热点,它巧妙地将卷积码和交织器结合起来,实现了随机编码的思想;同时,采用了软输出迭代译...Ocean is the valuable treasure of sustainable development of human society, and is the last living space of human beings in 21st century, and underwater communication technology has a close contract with national defence, ocean exploitation, environment monitoring, marine fish culture and so on. Because the acoustic wave is most effective for underwater communication, underwater acoustic communica...学位:理学硕士院系专业:海洋与环境学院海洋学系_海洋物理学号:20042703
Biological process of phosphorus turnover in surface water body of Xiamen Harbor. Ⅱ:Grazing pressure of copepod on phytoplankton
为了解桡足类在磷的生物地球化学循环中的作用,于2005年5、8、11月和2006年3月分别在厦门时间序列站(XMTS)采用肠道色素法,研究了桡足类对浮游植物的现场摄食率,同步分析了桡足类的种类组成和数量变化,进而得到桡足类群体对浮游植物的摄食率.结果表明:厦门港桡足类对浮游植物的年平均摄食率为55.53μg.m-3.d-1;其中秋季最高,为108.98μg.m-3.d-1,夏季最低,为7.18μg.m-3.d-1.根据试验数据估算,厦门港桡足类对浮游植物现存量的摄食压力四季平均为1.81,春、夏、秋、冬分别为3.22、0.06、3.52和0.46.To understand the roles of copepod in the biogeochemical cycling of phosphorus,gut fluorescence method was applied to examine in situ the grazing rate of copepod on the phytoplankton in Xiamen Time Station(XMTS) in May,August and November 2005 and March 2006.In the meanwhile,the abundance and species composition of copepod were investigated,and the grazing pressure of copepod on the phytoplankton was estimated.The results showed that the annual average grazing rate of copepod was 55.53 μg·m-3·d-1,being the highest(108.98 μg·m-3·d-1) in autumn and the lowest(7.18 μg·m-3·d-1) in summer.Based on the estimation from our experimental data,the daily grazing rate of copepod populations on the phytoplankton in Xiamen Harbor was,on annual average,about 1.81% of the phytoplankton's standing stock,with the values in spring,summer,autumn,and winter being 3.22%,0.06%,3.52% and 0.46%,respectively.国家自然科学基金资助项目(40376021
基于虚拟标签与循环校验的RFID定位算法
目前在室内定位中,rfId是一种被广泛使用的技术。本文详细研究了使用主动标签进行室内定位的相关技术与算法,同时在lAndMArC算法的基础上,提出了一种改进的定位算法,并引入了一种称为循环校验的校正机制来提高定位的精确率。最后,通过实验数据可以看出,该算法大大提高了定位的精确度
Neighboring / Adjacent Coupling Relationship Between Urbanization and Farmland Safety Based on the Decoupling Theory
当前我国快速城市化推进对半城市化、农村等近程区域分布的耕地产生直接、强烈的影响,也对耕地安全造成强大的胁迫效应。为此,构建城市化-耕地安全综合评; 价指标体系,分别计算城市化指数和耕地安全胁迫指数,并基于脱钩理论方法对城市化水平与耕地安全水平的近程耦合关系进行量化分析。以江苏省连云港市为例,; 定量分析20002014年间其城市化水平与耕地安全的脱钩-耦合关系及耕地安全对城市化进程的响应程度。结果表明,; 20002014年间,连云港市城市化指数持续增高,耕地安全胁迫指数波动降低;; 20002007年为强脱钩、弱脱钩、扩张负脱钩及扩张脱钩的波动状态;; 20082014年呈更加强烈的波动状态,包括20082012年的强脱钩和2013年的扩张负脱钩状态,这反映出区域发展规划、土地利用规划和城市总体; 规划的实施对这一典型近程耦合系统产生了较大影响。研究期内连云港市城市化水平大幅提高,耕地安全所受胁迫程度不断降低,两者虽总体呈强脱钩关系,但仍需; 注意近程耦合结果波动性较大所揭示的不确定性问题,需要谨慎权衡城市化相关政策对耕地安全的影响。与过去的宏观、单一指标模型相比,基于近程耦合关系提出; 的多指标脱钩-耦合模型更具综合性,能更加全面、精细化分析快速城市化进程与耕地安全保护之间的复杂关系,为半城市化地区景观安全格局评估提供支撑,为城; 市化与耕地保护之间的协调发展提供决策支持。The current rapid development of urbanization in China has directly and; seriously affected farmlands distribution in its para-urbanized; neighboring /adjacent regions,and also posed severe stresses on safety; of these land. It is,therefore,essential to build up a comprehensive; urbanization and farmland safety assessment indicator system,work out; quantitatively urbanization index and farmland safety stress index,and; analyze quantitatively neighboring coupling relations between; urbanization and arable land safety based on the decoupling theory and; method. A case study was conducted of Lianyungang City of Jiangsu; Province to explore quantitatively coupling-decoupling relationship; between urbanization and farmland safety and response of farmland safety; to the progress of urbanization during the period from 2000 to 2014.; Results show that during the study period,urbanization index of; Lianyungang City increased steadily,while farmland safety stress index; fluctuated with a declining trend. Their relationship displayed a wavy; trend from 2000 to 2007,i.e. strong decoupling-weak decoupling-expanding; negative decoupling-expanding connection and a strong fluctuation curve; from 2008 to 2014,including strong decoupling during 2008-2012 and; expanding negative decoupling in 2013,which reflects strong impacts of; the implementation of the regional development,land use and city overall; programs on this typical neighboring / adjacent coupling system. During; the study period,Lianyungang City made a huge and steady progress in; urbanization, while reducing fluctuation of its stress on farmland; safety. Though the two posed a strong decoupling relationship,the; problem of uncertainty reflected in the huge fluctuation of the result; of the neighboring /adjacent decoupling calls for high attention,and the; influence urbanization had on farmland safety needs to be weighed; prudently. Compared to the macroscopic single indicator models used in; the past,the multi-index decoupling-coupling model built for the; neighboring coupling relationship is more comprehensive and capable of; analyzing the complex relationship between rapid urbanization and; protection of farmland safety in a more holistic and finer way.; Furthermore,it may provide theoretical support to landscape safety; assessment of para-urbanizd regions and to decision-making on harmonized; development of both urbanization and protection of farmland.国家自然科学基金; 厦门大学大学生创新创业训练计划; 中国科学院大学生创新实践训练计
结合电子设计竞赛的“电力电子技术”课程教学改革实践
电子设计竞赛是提高学生动手能力、加强创新设计能力、增进团队合作等能力的有效手段,同时也能促进高校相关课程的改革。\"电力电子技术\"课程涉及电子技术、控制技术和电力技术,主要内容包括电力电子器件、整流电路、逆变电路、直流-直流变换、交流-交流变频、PWM控制技术及软开关等,课程实践性和工程性都很强。根据\"电力电子技术\"课程特点及存在的问题,提出相应的课程教学改革思路并加以实践,包括将\"电力电子技术\"课程与电子设计竞赛结合,把电赛题目带进课堂,通过案例式教学讲授知识点,积极动员学生参与电子设计竞赛,积累好的作品反馈于课程教学等。结果表明:结合电子设计竞赛的\"电力电子技术\"课程选课学生数有明显提升,参与电子设计竞赛的学生人数和获奖比例有一定提高
Autophagy Inhibition by Chloroquine Sensitizes Cervical Cancer SiHa Cells to CPT Treatment
自噬诱导是肿瘤细胞对化疗药物抵抗性的原因之一,该研究探讨溶酶体抑制剂氯喹对喜树碱(camptothecin,CPT)诱导的宫颈癌细胞Si Ha死亡的增敏效果。CPT和/或氯喹处理宫颈癌Si Ha细胞,MTT法检测细胞增殖,DAPI和TUNEL染色观察细胞凋亡,Western blot和免疫荧光检测自噬及凋亡相关蛋白。结果发现,CPT处理后,Si Ha细胞MAP1LC3B荧光点和LC3II(microtubuleassociated protein light chain 3II)蛋白水平增加,p62荧光点和蛋白质水平则减少;而采用氯喹特异抑制自噬后,可明显提高CPT诱导的细胞凋亡、caspase-9的激活和PARP(poly ADP-ribose polymerase)的切割,而全长caspase-2水平显著下降。以上结果提示,氯喹可通过抑制细胞自噬而增强宫颈癌细胞株Si Ha对CPT诱导细胞凋亡的敏感性。The autophagy induction is one of the reasons for the resistance of tumor cells to chemotherapy drugs. In this study, the enhanced sensitivity of cervical cancer Si Ha cells to camptothecin(CPT)-induced cell death by chloroquine(a lysosome inhibitor) was investigated. The cell viability was detected by MTT assay, meanwhile, apoptosis was observed by DAPI and TUNEL, autophagy related proteins and apoptosis proteins were analyzed by immunofluorescence(IF) staining and Western blot in Si Ha cells after CPT treatment alone or combined with chloroquine. The results found that in Si Ha cells with CPT treatment the autophagy related protein LC3 foci and microtubule-associated protein light chain 3II(LC3II) protein level was increased, but p62 foci and protein level was decreased. When autophagy was inhibited by chloroquine, the CPT-induced apoptosis was obviously enhanced, and caspase-9 was activated and PARP was cleaved, but full length caspase-2 was decreased. Taken together, these results indicated that the inhibition of autophagy by chloroquine could sensitize cervical cancer Si Ha cells to CPT inducing cell apoptosis.山西省自然科学基金(批准号:2014021037-9);; 山西医科大学汾阳学院博士启动基金(批准号:1301);山西医科大学汾阳学院科研项目基金(批准号:1422)资助的课题~
Bacterial community and its relation to environmental variables in a subtropical stratified reservoir for drinking water supply in autumn
水库在我国东南沿海地区是重要的饮用水水源地,对地区经济发展和社会稳定起到重要作用。选择亚热带地区典型的热分层水库——福建莆田东圳水库,于2011年秋季稳定分层期,以水体温度的垂直变化特征为依据进行分层采样。应用PCrdggE和克隆测序的方法研究浮游细菌群落的垂直分布特征,利用多元统计分析揭示细菌群落与热分层水体理化指标之间的关系。结果显示:溶解氧、电导率、叶绿素A、总氮、氨氮及硝氮在上下层水体中的分布有显著差异,下层缺氧区细菌的SHAnnOnWIEnEr指数和dggE条带数明显高于上层好氧区,表明东圳水库热分层水体中存在明显的物理、化学及生物分层现象。测序结果表明β-变形菌可能是东圳水库中占优势的细菌类群,统计结果提示溶解氧是显著影响细菌群落组成的环境因子。热分层水体的物理化学分层与水体细菌群落结构密切相关,提示水库生态学研究应对水体热分层给予重视。Fujian reservoirs in southeast China are important water resources for economic and social sustainable development,although few have been studied previously.Dongzhen Reservoir,a typical subtropical stratified reservoir in Fujian,was chosen for investigation of bacterial distribution,composition and diversity in autumn 2011.As the only built large reservoir in Putian City,it plays an important role in irrigation,flood control,hydroelectric power,and water supply.Dongzhen Reservoir shows an obvious phenomenon of water thermal stratification during summer and autumn,thus creates a unique gradient of environmental variables along the water column.We investigated the bacterial community and its relation to environmental variables in this study for a better understanding of vertical distribution of bacterial community and theprimary environmental drivers in a stratified reservoir.Five water samples were collected from five different depths according to the vertical changes of temperature.Both PCR-DGGE and sequencing were used to investigate the bacterial community and diversity.Moreover,physical and chemical parameters were measured according to the national standard methods.Multivariate statistical techniques were used to examine the relationship between bacterial community and environmental variables.Principal component analysis( PCA) clearly showed that water temperature,dissolved oxygen( DO),chlorophyll a( Chl a),total nitrogen( TN),ammonia nitrogen( NH4-N),nitrite / nitrate nitrogen( NOx-N) and electric conductivity of the upper aerobic zone were differed from those of the deeper anoxic zone.Both the number of DGGE bands and the Shannon-Wiener index of the deeper anoxic zone were higher than those of the upper aerobic zone.Further,two groups were distinguished by the cluster analysis of bacterial communities based on the Bray-Curtis similarity.Thus,Dongzhen Reservoir presented an obviously physical,chemical,and biological stratified phenomenon.Seven bands that common to all sampling depths were extracted and sequenced,and among which four were identified as Betaproteobacteria,indicating that Betaproteobacteria were the most dominant taxa in Dongzhen Reservoir in autumn.Bacterial community composition and diversity differed greatly among different sampling depths,and these differences were closely related to the physical and chemical stratification of the water body.Redundancy analysis( RDA) demonstrated DO was the significant environmental variable that shaping the bacterial community and diversity( P < 0.01).Therefore,we should pay more attention to DO and thermal stratification of reservoirs for sustainable reservoir management.国家重大科学研究计划(2012CB956103); 中国科学院知识创新工程方向项目(KZCX2-YW-QN401); 国家自然科学基金面上项目(31172114); 福建省杰出青年科学基金项目(2012J06009
庚型肝炎病毒基因在大肠杆菌中表达的初步研究
利用原核表达载体 pRSET或 (和 )pGEX在大肠杆菌内表达了覆盖庚型肝炎病毒 (HGV)C NS3和NS5区的多段基因。CE1、E2、NS3、NS5及NS3 NS5嵌合基因等的 8段基因均有高效表达 ,各重组蛋白产量与菌体总蛋白之比在 10 %~ 35 %之间。对以上重组蛋白进行免疫学筛选 ,证实其中 7个重组蛋白均具免疫学活性 ,在一定程度上确定了重组HGV抗原表位的分布 ,为HGV的血清学和免疫学诊断试剂的研究奠定了坚实基
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