检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

坛紫菜耐高温品系选育及经济性状的初步研究

海洋学报 2008年第5期30卷 100-106页

作者：陈昌生纪德华谢潮添徐燕梁艳郑永健史修周王凤霞赵玲敏集美大学水产学院福建厦门361021

将人工杂交选育的坛紫菜新品系Z-26，Z-61，Z-81，Z-17的子3代（F3）与野生型对照组进行遗传性状的比较，旨在筛选耐高温品系。实验结果表明：（1）在高温29℃下培养40 d，人工选育的4个新品系丝状体均能正常生长发育，其中Z-26丝状体... 详细信息

将人工杂交选育的坛紫菜新品系Z-26，Z-61，Z-81，Z-17的子3代（F3）与野生型对照组进行遗传性状的比较，旨在筛选耐高温品系。实验结果表明：（1）在高温29℃下培养40 d，人工选育的4个新品系丝状体均能正常生长发育，其中Z-26丝状体生长较快，Z-61在29℃下较易成熟，95%的营养藻丝发育成孢子囊枝，Z-17只有30%形成孢子囊枝；（2）Z-26和Z-61品系的叶状体在30℃下培养10 d，虽然藻体变白，但没有死亡，此时将其移至21℃下恢复培养3-4 d，藻体逐渐恢复为原有的色泽；（3）Z-81和Z-17的叶状体在29℃下培养7-10 d，虽然藻体发白但尚未死亡，移至21℃下培养基本可恢复正常，但在30℃下培养10 d，藻体腐烂不可恢复；（4）野生型对照组不耐高温，藻体在27℃下培养5 d就腐烂死亡，人工选育的4个品系耐受高温的幅度比野生型对照组高1-3℃；（5）4个品系叶状体在26-28℃温度下培养10 d后，其主要的藻胆蛋白和叶绿素a的含量与21℃培养下的含量差异不显著，说明短时间的高温培养并不影响其品质。

关键词：坛紫菜品系高温生长发育

The Bryopsis hypnoides plastid genome:Multimeric forms and complete nucleotide sequence

在线全文

学校读者我要写书评

暂无评论

The Bryopsis hypnoides plastid genome:Multimeric forms and c...

庆祝中国藻类学会成立30周年暨第十五次学术讨论会

作者： Fang Lü~(1 3 5) Wei Xü~(2 3 5) chao tian~(1 5) Guangce Wang~(1 *) Jiangfeng Niu~1 Guanghua Pan~4 Songnian Hu~3 1.Institute of Oceanology the Chinese Academy of Sciences(IOCAS) Qingdao 266071 China 2.Beijing Genomics Institute Chinese Academy of Sciences(BGICAS) Beijing 101300 China 3.Graduate University of the Chinese Academy of Sciences Beijing 100039 China 4.College of Marine Science and Engineering tianjin University of Science and Technology tianjin 300457 China

＜正＞Bryopsis hypnoides Lamouroux is a siphonous green alga,and its extruded protoplasm can aggregate spontaneously in seawater and develop into mature *** chloroplast of *** is the biggest organelle in the cell and shows strong *** better understand this organelle,we sequenced and analyzed the chloroplast genome of this green alga.A total of 111 functional genes, including 69 potential protein-coding genes,5 ribosomal RNA genes,and 37 tRNA genes were *** genome size（153,429 bp）,arrangement,and inverted-repeat（IR）-lacking structure of the *** chloroplast DNA（cpDNA） closely resembles that of Chlorella ***,our cytogenomic investigations using pulsed-field gel electrophoresis（PFGE） and southern blotting methods showed that the *** cpDNA had multimeric forms,including monomer,dimer,trimer,tetramer,and even higher multimers,which is similar to the higher order organization observed previously for higher plant *** relative amounts of the four multimeric cpDNA forms were estimated to be about 1,1/2,1/4, and 1/8 based on molecular hybridization *** analyses based on a concatenated alignment of chloroplast protein sequences suggested that *** is located in a lineage with Oltmannsiellopsis viridis and Pseudendoclonium akinetum within the *** of the results suggest that the autonomy of the chloroplasts of *** has little to do with the size and gene content of the cpDNA,and the IR-lacking structure of the chloroplasts indirectly demonstrated that the multimeric molecules might result from the random cleavage and fusion of replication intermediates instead of recombinational events.

关键词： Bryopsis hypnoides plastid genome phylogenetic analyses pulsed-field gel electrophoresis(PFGE) multimeric forms

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

改进TD3算法的机械臂三维路径规划方法

电光与控制 2025年第1期32卷 100-105页

作者：马天李超杨嘉怡西安科技大学计算机科学与技术学院西安710000

在军事航空领域中,复杂任务对机械臂路径规划提出了挑战。针对双延迟深度确定性策略梯度(TD3)算法学习效率低、样本利用率低的问题,提出了一种改进的TD3算法(Recurrent-TD3算法)。首先,将LSTM结合到策略网络与价值网络中,捕获航空控制... 详细信息

在军事航空领域中,复杂任务对机械臂路径规划提出了挑战。针对双延迟深度确定性策略梯度(TD3)算法学习效率低、样本利用率低的问题,提出了一种改进的TD3算法(Recurrent-TD3算法)。首先,将LSTM结合到策略网络与价值网络中,捕获航空控制任务中的时间序列信息,增强对时间序列变化的响应能力,使其能够在决策时考虑历史动作和状态,提高网络的表达能力;然后,将事后经验回放(HER)技术集成到TD3算法中,以解决任务中稀疏奖励难以学习的问题,通过将未达到目标的经验转化为达到新目标的经验,从而更有效地利用样本;最后,设计了一种基于包围盒的碰撞检测流程,以提高机械臂在军用航空任务中的安全性。实验表明,该算法相比于其他算法能够更快地找到一条无碰撞的路径,且平均路径长度最短。

关键词：机械臂路径规则 TD3 长短期记忆网络事后经验回放技术

维普期刊数据库博看期刊

Cu^(2+)污染下农作物叶片特征光谱探究

在线全文

学校读者我要写书评

暂无评论

光谱学与光谱分析 2025年第1期45卷 264-271页

作者：张超吴轩杨可明齐钒宇夏天中国地质调查局发展研究中心北京100037 中国地质大学(北京)地球科学与资源学院北京100083 全国地质资料馆北京100037 中国矿业大学(北京)地球科学与测绘工程学院北京100083 中国资源卫星应用中心北京100094

为探究重金属胁迫下农作物污染响应的敏感叶型及谱段,设计了室外温室环境下的不同铜胁迫梯度玉米花盆试验。以玉米叶片为探究对象,利用仪器测定了出穂期玉米叶片的高光谱反射率数据以及叶片中重金属含量数据,为研究提供了基础数据。从... 详细信息

为探究重金属胁迫下农作物污染响应的敏感叶型及谱段,设计了室外温室环境下的不同铜胁迫梯度玉米花盆试验。以玉米叶片为探究对象,利用仪器测定了出穂期玉米叶片的高光谱反射率数据以及叶片中重金属含量数据,为研究提供了基础数据。从频率域角度,结合时频分析的方法设计了叶片光谱探测法(LSDM),获得了重金属铜胁迫下敏感叶型及谱段,为农作物重金属监测提供技术支撑。根据玉米的生长过程,从老叶(O)、中叶(M)、新叶(N)光谱350~1300 nm的全谱段和子谱段角度进行探究。(1)对铜胁迫下玉米叶片的高光谱反射率数据进行双微分(SOD)和包络线移除(CR),转换到频率域上,结合时频分析的方法进行Daubechies小波6层分解。(2)根据信号异常点、小波高值点和SODCR曲线高值点,定义玉米叶片的光谱异常参数(SAP)。异常变化反射率ACR(异常反射率与其后一个相邻波段反射率差值的绝对值);异常小波系数AWC(异常小波系数与其后一个相邻波段小波系数差值的绝对值);异常SODCR值ASV(异常点SODCR值与其后一个相邻波段SODCR值差值的绝对值)。通过光谱异常参数与玉米叶片重金属含量的相关关系,探究对铜污染响应敏感的叶型及谱段。结果表明,叶片光谱探测法LSDM能高效地对玉米叶片弱信息进行增强,并准确定位出重金属铜胁迫引起的光谱异常谱段位置,异常变化范围集中在350~800 nm内;光谱异常参数能定量地衡量玉米叶片在重金属铜胁迫下的光谱异常;在不同铜胁迫梯度下,玉米新叶(N)为敏感叶型,敏感谱段为蓝边、绿峰、黄边、红谷。该研究有望为其他谷类农作物及其冠层尺度重金属监测提供技术支撑。

关键词：重金属胁迫玉米叶片高光谱敏感叶型敏感谱段

Optimized operation plan for sewer sediment control

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第5期11卷 335-341页

作者： Yong-chao ZHOU tian LI Institute of Municipal Engineering Zhejiang University Hangzhou 310058 China College of Environmental Science and Engineering Tongji University Shanghai 200096 China

Severe operational problems of sediment deposition have frequently occurred in stormwater sewer systems in Shanghai city due to the flat topography of the area and serious illicit connections. To control sewer sediment and its subsequential problems,optimized operation plans were proposed and an innovative performance assessment method was developed. Simula-tion results demonstrated that,through changing the way of pump operation and installing necessary actuators in the system,the optimized operations,especially batch intermittent intercept plan,effectively improved the flow velocity in the entire system in dry-weather condition. In conclusion,the optimized operation is an innovative idea for improving the performance and solving the problem of sediment deposition in the sewer system in Shanghai,China.

关键词： Sewer system Sediment control Performance assessment Simulation

THE SECOND-ORDER HYDROELASTIC ANALYSIS OF A SWATH SHIP MOVING IN LARGE-AMPLITUDE WAVES

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2006年第6期18卷 631-639页

作者： tian chao WU You-Sheng School of Naval Architecture Ocean and Civil Engineering Shanghai Jiaotong University Shanghai 200030China China Ship Scientific Research Center Wuxi 214082 China

Based on the second order hydroelasticity theory of ships, the numerical methods and the calculated results of the non-linear hydroelastic responses of a ship traveling in rough seas were investigated. The non-linear hydrodynamic actions induced by the rigid body rotations and the variations of instantaneous wetted surface area were included in the second order analysis. The first order wave potentials and responses, which are sure to make the major contributions to the second order hydrodynamic actions, were obtained by employing the translating and pulsating source Green function and the Kelvin steady wave flow solution based on the linear three-dimensional hydroelasticity theory. The influences of the forward speed and the steady wave flow on the responses, and the differences of the predicted non-linear responses were illustrated by the numerical examples of a SWATH ship traveling with forward speed of 12 kn in irregular waves.

关键词： hydroelaticity, non-linear responses, second order forces, translating and pulsating source, SWATH (Small Waterplane Area Twin Hull) ship

Unifying logic rules and machine learning for entity enhancing

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2020年第7期63卷 142-160页

作者： Wenfei FAN Ping LU chao tian School of Informatics University of Edinburgh Shenzhen Institute of Computing Sciences Shenzhen University Beijing Advanced Innovation Center for Big Data and Brain Computing Beihang University Alibaba Group

This paper proposes a notion of entity enhancing, which unifies entity resolution and conflict resolution, to identify tuples that refer to the same real-world entity and at the same time, correct semantic inconsistencies. We propose to unify rule-based and machine learning(ML) methods for entity enhancing, by embedding ML classifiers as predicates in logic rules. We model entity enhancing by extending the chase. We show that the chase warrants correctness justification and the Church-Rosser property. Moreover, we settle fundamental problems associated with entity enhancing, including the enhancing, consistency, satisfiability,and implication problems, ranging from NP-complete and coNP-complete to Π~p-complete. Taken together,these provide a new theoretical framework for unifying entity resolution and conflict resolution.

关键词： logic rules machine learning entity enhancing entity resolution conflict resolution

Bibliometric Analysis of Global Research Progress on Coastal Flooding 1995–2016

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Geographical Science 2018年第6期28卷 998-1008页

作者： GAO chao RUAN tian Department of Geography & Spatial Information Techniques Ningbo University College of Territorial Resources and Tourism Anhui Normal University

Global research progress on coastal flooding was studied using a bibliometric evaluation of publications listed in the Web of Science extended scientific citation index. There was substantial growth in coastal flooding research output, with increasing publications, a higher collaboration index, and more references during the 1995–2016 period. The USA has taken a dominant position in coastal flooding research, with the US Geological Survey leading the publications ranking. Research collaborations at institutional scales have become more important than those at global scales. International collaborative publications consistently drew more citations than those from a single country. Furthermore, coastal flooding research included combinations of multi-disciplinary categories, including ‘Geology' and ‘Environmental Sciences & Ecology'. The most important coastal flooding research sites were wetlands and estuaries. While numerical modeling and 3 S(Remote sensing, RS; Geography information systems, GIS; Global positioning systems, GPS) technology were the most commonly used methods for studying coastal flooding, Lidar gained in popularity. The vulnerability and adaptation of coastal environments, their resilience after flooding, and ecosystem services function showed increases in interest.

关键词： coastal flood scientific outputs bibliometric analysis research trends Web of Science

Effects of material of metallic frame on the penetration resistances of ceramic-metal hybrid structures

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2020年第1期16卷 77-87页

作者： Xuanyi An chao tian Qitian Sun Yongxiang Dong State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China

The effects of metallic material on the penetration resistances of ceramic-metal hybrid structures against vertical long-rod tungsten projectiles were studied by artillery-launched experiments and numerical *** structures with rectangular cores in transverse orthogonal arrangement and slidefitting ceramic inserts of zirconia toughened alumina prisms were fabricated with titanium alloy TC4(Ti6 Al4 V),AISI 4340 steel and 7075 aluminum alloy panels,*** results showed that the hybrid structure of Ti6A14V exhibited the highest penetration resistance,followed by that of 7075 aluminum alloy with the same area *** penetration resistance of the hybrid structure of AISI4340 steel was the *** underlying mechanisms showed that the metallic material of a ceramicmetal hybrid structure can directly affect its energy absorption from the impact projectile,which further affects its penetration *** metallic frames exhibited different failure characteristics,resulting in different constraint conditions or support conditions for ceramic *** high penetration resistance of the Ti6Al4V hybrid structure was due to its stronger back support to ceramic prisms as compared with that of AISI 4340 steel hybrid structure,and better constraint condition for ceramic prisms by metallic webs as compared with that of 7075 aluminum alloy hybrid *** results of mass efficiency and thickness efficiency showed that the Ti6Al4V hybrid structure has advantages in reducing both the thickness and the mass of protective *** addition,because the ceramic-metal hybrid structures in the present work were heterogeneous,impact position has slight influence on their penetration resistances.

关键词： Hybrid structures Zirconia toughened alumina Penetration resistance Long-rod projectile Metallic frame