检索结果-南通市图书馆

高寒区‘青引1号’燕麦种子产量对氮、磷、钾肥的响应

在线全文

学校读者我要写书评

暂无评论

草业科学 2024年第2期41卷 345-355页

作者：刘慢刘文辉刘凯强贾志锋梁国玲青海省畜牧兽医科学院青海西宁810016

为明确青藏高原高寒地区施用氮、磷、钾肥对‘青引1号’燕麦(Avena sativa‘Qingyin No.1’)种子产量的影响,本研究以‘青引1号’燕麦为研究对象,在青海省西宁市湟中区分别设置氮磷钾单施试验,其中氮肥水平为(N_(0)、N_(30)、N_(45)、N_... 详细信息

为明确青藏高原高寒地区施用氮、磷、钾肥对‘青引1号’燕麦(Avena sativa‘Qingyin No.1’)种子产量的影响,本研究以‘青引1号’燕麦为研究对象,在青海省西宁市湟中区分别设置氮磷钾单施试验,其中氮肥水平为(N_(0)、N_(30)、N_(45)、N_(60)、N_(75)、N_(90)和N_(105))、磷肥水平为(P_(0)、P_(15)、P_(30)、P_(45)、P_(60)、P_(75)和P_(90))、钾肥水平为(K_(0)、K_(10)、K_(20)、K_(30)、K_(40)、K_(50)和K_(60))。以确定最佳施肥水平,明确不同肥料对燕麦种子增产的效果,完善该品种在种子生产过程中的肥料管理技术,为青海地区燕麦种子生产中肥料的施用配比提供科学指导。结果表明:氮、磷、钾肥分别以60、60和50kg·hm^(-2)处理时种子产量最高,分别达4 358.6、6 285.0和6 729.1 kg·hm^(-2),以钾肥对燕麦种子增产效果最为明显;氮肥可显著提高燕麦小穗数、穗长和千粒重,磷肥可促进燕麦有效分蘖、粒宽和单序籽粒重增加,而钾肥则有助于有效分蘖数、粒长、粒宽、单序籽粒重和千粒重提升;氮、磷、钾肥单施水平下以粒宽和小穗数对种子产量直接效应最大,小花数和粒宽通过对其他产量性状的间接作用对种子产量产生增益效果。高寒地区‘青引1号’燕麦种子生产中,钾肥的施用可有效提高‘青引1号’燕麦种子产量。

关键词：施肥水平燕麦高寒地区通径分析氮磷钾回归分析产量性状

Tuning electronic configuration of WP_(2) nanosheet arrays via nickel doping for high-efficiency hydrogen evolution reaction

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2021年第4期30卷 17-24页

作者： Wei liu Peng Geng Shiqing Li wenhui liu Dayong Fan Huidan Lu Zhenhuan Lu Yongping liu Guangxi Key Laboratory of Electrochemical and Magneto-chemical Functional Materials College of Chemistry and BioengineeringGuilin University of TechnologyGuilin 541004GuangxiChina

Modulate the electronic structure and surface energy by nanostructure and heteroatom doping is an efficient strategy to improve electrocatalytic activity of hydrogen evolution reaction(HER).Herein,nickel incorporated WP_(2) self-supporting nanosheet arrays cathode was synthesized on carbon cloth(Ni-WP_(2) NS/CC)by in-situ phosphating reduction of the Ni-doped WO3.It shows that heteroatom doping and the three-dimensional(3D)nanosheet arrays morphology both facilitate to reduce the interfacial transfer resistance and increase electrochemical-active surface areas,which effectively improve electrocatalytic hydrogen evolution reaction(HER)activity.The optimized catalyst,1%Ni-WP_(2) NS/CC,exhibits an outstanding electrocatalytic performance with an overpotential of 110 m V at 10 m A cm^(-2) and a Tafel slope of 65 m V dec^(-1) in the acid solution.DFT calculations further demonstrate the nickel doping can adjust the intrinsic structure of electronics,lower the Gibbs free energy of adsorption of hydrogen(DGH*),and effectively improve the HER performance.

关键词： Heteroatom doping Tungsten phosphide Nanosheet arrays Electrocatalyst Hydrogen evolution reaction

Towards intelligent design optimization: Progress and challenge of design optimization theories and technologies for plastic forming

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2021年第2期34卷 104-123页

作者： Heng LI Jingchao YANG Guangyao CHEN Xin liu Zhao ZHANG Guangjun LI wenhui liu State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Poly technical UniversityXi'an 710072China Chengdu Aircraft Industry(Group)Corporation Ltd. Chengdu 610092China High Temperature Wear Resistant Materials and Preparation Technology of Hunan Province National Defence Science and Technology Laboratory Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and ConversionSchool of Materials Science and EngineeringHunan University of Science and TechnologyXiangtan 411201China

Plastic forming is one of enabling and fundamental technologies in advanced manufacturing chains. Design optimization is a critical way to improve the performance of the forming system, exploit the advantages of high productivity, high product quality, low production cost and short time to market and develop precise, accurate, green, and intelligent(smart) plastic forming technology. However, plastic forming is quite complicated, relating to multi-physics field coupling,multi-factor influence, multi-defect constraint, and triple nonlinear, etc., and the design optimization for plastic forming involves multi-objective, multi-parameter, multi-constraint, nonlinear,high-dimensionality, non-continuity, time-varying, and uncertainty, etc. Therefore, how to achieve accurate and efficient design optimization of products, equipment, tools/dies, and processing as well as materials characterization has always been the research frontier and focus in the field of engineering and manufacturing. In recent years, with the rapid development of computing science, data science and internet of things(Io T), the theories and technologies of design optimization have attracted more and more attention, and developed rapidly in forming process. Accordingly, this paper first introduced the framework of design optimization for plastic forming. Then, focusing on the key problems of design optimization, such as numerical model and optimization algorithm,this paper summarized the research progress on the development and application of the theories and technologies about design optimization in forming process, including deterministic and uncertain optimization. Moreover, the applicability of various modeling methods and optimization algorithms was elaborated in solving the design optimization problems of plastic forming. Finally, considering the development trends of forming technology, this paper discusses some challenges of design optimization that may need to be solved and faced in forming process.

关键词： Advanced manufacturing Design optimization Deterministic optimization(DOP) Intelligent design optimization(IDO) Plastic forming Uncertain optimization(UOP)

基于改进DBSCAN空间聚类算法的北京市人工智能产业集聚格局研究

在线全文

学校读者我要写书评

暂无评论

地理科学 2024年第2期44卷 238-247页

作者：张平范文慧贾婧刘义清华大学自动化系北京100084 聊城大学历史文化与旅游学院山东聊城252059

企业作为产业的重要主体,其发展直接表征着产业的发展,企业的空间格局对产业的发展及资源配置具有重要的引导意义。本文基于北京市工商注册在业的人工智能企业数据,提取企业注册地址并转化为地理位置信息,通过改进有噪声的应用背景下的... 详细信息

企业作为产业的重要主体,其发展直接表征着产业的发展,企业的空间格局对产业的发展及资源配置具有重要的引导意义。本文基于北京市工商注册在业的人工智能企业数据,提取企业注册地址并转化为地理位置信息,通过改进有噪声的应用背景下的基于密度的空间聚类算法(DBSCAN),分析北京市细粒度层级下人工智能产业集聚在全市域的空间分布格局特征。在DBSCAN算法改进方面,首先调整Minpts参数为企业注册资本总额与企业数量2个维度,企业数量大于5家且注册资本总额大于一定数额,为形成产业集聚区的2个必要条件;其次提取簇内位于边界的企业位置点作为集聚区地理边界点,将边界点连线并绘制形成人工智能产业集聚区。本文重点分析了企业注册资本和地理聚合半径对人工智能产业集聚区形成的影响,同时采用核密度估计法作为参照验证,表明改进DBSCAN方法具有精确刻画产业集聚区地理边界和确定不同规模产业集聚区的优势。通过分析得知,北京市人工智能产业集聚具有明显的中心分布特征,集中在城六区,呈现“两大龙头带动,北京市全域遍地开花”的分布情况,海淀区、朝阳区处于人工智能集聚程度高水平,相较其他区域,人工智能产业发展遥遥领先;西城区、东城区、丰台区、昌平区处于集聚程度较高水平;通州区、大兴区、平谷区、密云区、石景山区、房山区、门头沟区、怀柔区、顺义区处于集聚程度中等水平;延庆区集聚程度较低。通过改进DBSCAN算法精确定位出中关村区域、上地西二旗区域、五道口区域、望京区域、国贸区域、亦庄经开区等人工智能产业集聚区。进一步探究发现,海淀区的人工智能科研人才优势,朝阳区的信息技术领域企业基础,是两区人工智能发展突出的直接原因。延庆区等郊区远离北京市中心城区,产业资源匮乏,同时由于区域功能定位限制等原因,导致人工智能产业集聚水平较低,表明这些区域人工智能产业发展较为缓慢。

关键词：人工智能产业集聚改进DBSCAN算法核密度估计 GIS 北京

A model for carbon isotope distribution of methane duringdiagenesis

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第7期43卷 576-578页

作者： Ping Guan Yongchang Xu wenhui liu Darui Wang Peking Univ Dept Geol Beijing 100871 Peoples R China Chinese Acad Sci Lanzhou Inst Geol Lanzhou 730000 Peoples R China Res Inst Petr Explorat & Dev Beijing 100083 Peoples R China

The evolution of methane carbon isotope with depth has been discussed based on diagenetic reaction kinetics and isotopic Rayleigh fractionational theory. A mathematical model to describe data of methane carbon isotope... 详细信息

关键词： methane carbon isotope maturity Rayleigh fractionation.

The flow behavior in as-extruded AZ31 magnesium alloy under impact loading

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2018年第2期6卷 180-188页

作者： Biwu Zhu Xiao liu Chao Xie wenhui liu Changping Tang Liwei Lu Key Laboratory of High Temperature Wear Resistant Materials Preparation Technology of Hunan Province Hunan University of Science and TechnologyXiangtan 411201China The Faculty of Mechanical Engineering and Mechanics Ningbo UniversityNingbo 315211China

As-extruded AZ31 magnesium alloy samples were compressed at ambient temperature and strain rates of 1000-3000 s^(−1).The fracture surfaces of cracked samples,the evolution of microstructures and macrotextures were detected.The received flow curves exhibit an abnormal behavior at strain rates above 1500 s^(−1).A strain constitutive model based on strain equivalent principle was applied to analyze the flow curves of the damaged samples.The results indicate that the abnormal flow behaviors of the fractured samples are related to the increasing area of crack surfaces,and kinetic energy during dynamic crack nucleation and propagation.The initiation of the micro-crack also causes obvious flow softening in the cracked samples.The shapes of flow stresses of the intact samples are affected by twinning.©2018 Published by Elsevier B.V.on behalf of Chongqing University.

关键词： Magnesium alloy Flow behavior Fracture Micro-crack Twinning.

江汉平原养殖水面结构转型路径及驱动机制研究

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

地理科学进展 2024年第5期43卷 921-935页

作者：刘文卉宋小青徐惠孝高厚兴中国地质大学(武汉)地理与信息工程学院区域生态过程与环境演变湖北省重点实验室武汉430074 自然资源部国土碳汇智能监测与空间调控工程技术创新中心武汉430074

深入理解淡水养殖水面结构转型是贯彻落实新发展理念和大食物观的必然要求,对促进全球可持续发展具有重要意义。然而,有关淡水养殖水面结构变化的研究还十分不足。论文在认识到淡水产品市场需求和河湖长制等水域管控政策对淡水养殖的影... 详细信息

深入理解淡水养殖水面结构转型是贯彻落实新发展理念和大食物观的必然要求,对促进全球可持续发展具有重要意义。然而,有关淡水养殖水面结构变化的研究还十分不足。论文在认识到淡水产品市场需求和河湖长制等水域管控政策对淡水养殖的影响基础上,综合运用Simpson多样性指数、地理要素重心模型和面板回归模型,从类型结构和空间结构两方面研究揭示江汉平原养殖水面的转型特征,着重探索市场诱致和政策管控共同作用下养殖水面结构转型的驱动机制。结果表明:①2001—2020年,江汉平原养殖水面从快速扩张转为扩张减缓,类型结构发生了“大水转小水、小水精养化、综合种养化主导”的转型,空间结构出现了“大水爬坡、小水向江”的转型趋势;②市场诱致性类型替代叠加政策强制性结构调整共同驱动了江汉平原养殖水面结构转型。其中,前者即以追求劳动生产力最大化为养殖目标的自下而上市场诱致性类型替代,后者即以河湖长制为代表的自上而下的水域管控政策实施导致的结构调整。此外,论文提出了加强江汉平原养殖水面结构转型调控的政策建议。研究结果有助于土地利用转型研究对象向养殖水面拓展,同时能够为从结构演化视角开展土地利用转型研究提供案例支撑。

关键词：养殖水面结构土地利用转型市场诱致江汉平原

在线全文

学校读者我要写书评

暂无评论

基于深度学习的实例分割边界框回归方法研究

哈尔滨工程大学学报 2024年第3期45卷 474-479,614页

作者：刘桂霞吴彦博李文辉王天昊吉林大学计算机科学与技术学院吉林长春130012 哈尔滨工程大学船舶工程学院黑龙江哈尔滨150001

针对实例分割任务中图像中可能出现相互遮挡或边缘模糊导致边界框定位不准确的问题,本文提出了一种新的边界框回归损失函数。将边界框位置预测转化为估计定位置信度随位置变化的概率分布;考虑坐标点间存在联系,提出一种面积差计算方法;... 详细信息

针对实例分割任务中图像中可能出现相互遮挡或边缘模糊导致边界框定位不准确的问题,本文提出了一种新的边界框回归损失函数。将边界框位置预测转化为估计定位置信度随位置变化的概率分布;考虑坐标点间存在联系,提出一种面积差计算方法;为了证明此方法可以很好地应用于先检测后分割的实例分割模型,本文使用Mask R-CNN作为基线。实验结果表明:在边界框检测及实例分割任务中,本文方法的精度优于其他方法,对于小物体的检测与分割效果更显著,训练和评估速度也更快。

关键词：计算机视觉深度学习卷积神经网络实例分割 Mask R-CNN 边界框回归 KL散度高斯分布

Two-dimensional materials for future information technology: status and prospects

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第6期67卷 1-147页

作者： Hao QIU Zhihao YU Tiange ZHAO Qi ZHANG Mingsheng XU Peifeng LI Taotao LI Wenzhong BAO Yang CHAI Shula CHEN Yiqi CHEN Hui-Ming CHENG Daoxin DAI Zengfeng DI Zhuo DONG Xidong DUAN Yuhan FENG Yu FU Jingshu GUO Pengwen GUO Yue HAO Jun HE Xiao HE Jingyi HU Weida HU Zehua HU Xinyue HUANG Ziyang HUANG Ali IMRAN Ziqiang KONG Jia LI Qian LI Weisheng LI Lei LIAO Bilu liu Can liu Chunsen liu Guanyu liu Kaihui liu Liwei liu Sheng liu Yuan liu Donglin LU Likuan MA Feng MIAO Zhenhua NI Jing NING Anlian PAN Tian-Ling REN Haowen SHU Litao SUN Yue SUN Quanyang TAO Zi-Ao TIAN Dong WANG Hao WANG Haomin WANG Jialong WANG Junyong WANG wenhui WANG Xingjun WANG Yeliang WANG Yuwei WANG Zhenyu WANG Yao WE Department of Applied Physics The Hong Kong Polytechnic University Key Laboratory for Micro-Nano Physics and Technology of Hunan Province College of Materials Science and EngineeringHunan University College of Integrated Circuits Zhejiang University Shenzhen Geim Graphene Center Shenzhen Key Laboratory of Layered Materials for Value-Added ApplicationsTsinghua-Berkeley Shenzhen Institute & Institute of Materials ResearchTsinghua Shenzhen International Graduate SchoolTsinghua University State Key Laboratory of Extreme Photonics and Instrumentation College of Optical Science and EngineeringInternational Research Center for Advanced PhotonicsZijingang CampusZhejiang University National Key Laboratory of Materials for Integrated Circuits Shanghai Institute of Microsystem and Information TechnologyChinese Academy of Sciences CAS Key Laboratory of Nanophotonic Materials and Devices & Key Laboratory of Nanodevices and Applications i-LabSuzhou Institute of Nano-Tech and Nano-Bionics (SINANO)Chinese Academy of Sciences College of Chemistry and Chemical Engineering Hunan University Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education) Department of PhysicsRenmin University of China School of Integrated Circuits Beijing National Research Center for Information Science and Technology (BNRist)Tsinghua University School of Electronic Science and Engineering Nanjing University The State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology Shaanxi Joint Key Laboratory of GrapheneSchool of MicroelectronicsXidian University Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education School of Physics and TechnologyWuhan University School of Integrated Circuits Huazhong University of Science and Technology Center for Nanochemistry (CNC) Beijing Science and Engineering Center for NanocarbonsBeijing National Laboratory for Molecular SciencesCollege of Chemistry and Molecular EngineeringPeking University State Key Laboratory for Artificial Microstruct

Over the past 70 years, the semiconductor industry has undergone transformative changes,largely driven by the miniaturization of devices and the integration of innovative structures and materials. Two-dimensional(2D) materials like transition metal dichalcogenides(TMDs) and graphene are pivotal in overcoming the limitations of silicon-based technologies, offering innovative approaches in transistor design and functionality, enabling atomic-thin channel transistors and monolithic 3D integration. We review the important progress in the application of 2D materials in future information technology, focusing in particular on microelectronics and optoelectronics. We comprehensively summarize the key advancements across material production, characterization metrology, electronic devices, optoelectronic devices, and heterogeneous integration on silicon. A strategic roadmap and key challenges for the transition of 2D materials from basic research to industrial development are outlined. To facilitate such a transition, key technologies and tools dedicated to 2D materials must be developed to meet industrial standards, and the employment of AI in material growth, characterizations, and circuit design will be essential. It is time for academia to actively engage with industry to drive the next 10 years of 2D material research.

关键词： two-dimensional (2D) materials information technology production technology standardization of characterization microelectronicdevices optoelectronic devices multi-functional integration