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导体网络阴极保护的新设计方法
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作者 惠子厚 《华北电力技术》 CAS 北大核心 1994年第3期43-48,62,共7页
在工业区和市区地下埋设的导体网络,广泛采用阴极保护。但对具有若干分支和结点的复杂的而互相衔接的延伸的导体网络,阴极保护设计中就遇上了如何在理论上预测其电势分布的问题。本文介绍的新设计方法,是根据网络各分支的无源双通道... 在工业区和市区地下埋设的导体网络,广泛采用阴极保护。但对具有若干分支和结点的复杂的而互相衔接的延伸的导体网络,阴极保护设计中就遇上了如何在理论上预测其电势分布的问题。本文介绍的新设计方法,是根据网络各分支的无源双通道模型,把整个网络作为线性导体的计算模型,这就把目前实践上根据试验计算、工程经验和近似经验法,变成可用传统的线性网络方程式求解,而且也很容易在计算机上完成。此方法已在一些情况下做过试验,其测试结果与理论上得到的电势场能很好地吻合。 展开更多
关键词 导体网络 阴极保护 电势场 设计
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全球半导体贸易网络结构演化及影响因素 被引量:1
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作者 顾伟男 范信言 +1 位作者 任亚文 古恒宇 《地理研究》 CSSCI CSCD 北大核心 2024年第8期2194-2214,共21页
在全球产业链加速重构背景下,准确把握全球半导体不同环节贸易网络组织结构演化态势及影响因素对诠释核心高技术产业视角下的新型世界格局具有重要意义。本文从产业链视角构建全球半导体贸易网络演化的理论框架,基于联合国贸易数据库中... 在全球产业链加速重构背景下,准确把握全球半导体不同环节贸易网络组织结构演化态势及影响因素对诠释核心高技术产业视角下的新型世界格局具有重要意义。本文从产业链视角构建全球半导体贸易网络演化的理论框架,基于联合国贸易数据库中半导体贸易数据,运用复杂网络、空间分析与负二项回归等方法,揭示2001—2022年全球半导体产业不同环节贸易空间格局、贸易网络拓扑结构和组织结构的演化规律及其驱动因素。研究结论如下:①制造设备贸易网络格局始终由美日以及部分西欧国家担任主要角色,制造材料和制成器件的主导权持续向东亚国家(地区)集中。贸易网络联系愈发紧密,并呈现出明显的幂律分布特征和小世界现象。②全球半导体贸易网络节点组织结构保持稳定的“核心-边缘”层次体系模式,节点类型以主导型和边缘型为主,网络关系组织演化具有显著的北半球分裂和南半球整合特征。③语言邻近性和良好的地缘经济关系对半导体贸易网络发展具有促进作用,地理邻近性的正向作用减弱,经济邻近性的抑制作用增强。国家经济发展水平、对外开放程度、科技发展水平均有不同程度的影响,社会治理水平的影响程度较小。 展开更多
关键词 导体贸易网络 空间格局 拓扑结构 组织结构 影响因素
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电气化铁路车网耦合系统时域仿真分析 被引量:1
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作者 孙正成 《中国高新科技》 2023年第14期64-67,共4页
针对我国电气化铁路中出现的低频振荡问题,文章在理论分析的基础上,根据实际参数建立了详细的全并联AT牵引供电系统仿真模型及CRH1型动车组仿真模型,仿真再现车网耦合系统低频振荡现象,分析了车网耦合系统低频振荡现象产生的原因。研究... 针对我国电气化铁路中出现的低频振荡问题,文章在理论分析的基础上,根据实际参数建立了详细的全并联AT牵引供电系统仿真模型及CRH1型动车组仿真模型,仿真再现车网耦合系统低频振荡现象,分析了车网耦合系统低频振荡现象产生的原因。研究表明,限制区段上投入的同型号动车数量和适当调整动车组网侧整流器控制参数可以消除低频振荡现象。 展开更多
关键词 车网耦合 时域仿真 低频振荡 导体链式网络模型
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Intelligent identifi cation method for near-surface ground fi ssures based on seismic data
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作者 Shi Su-Zhen Gu Jian-Ying +3 位作者 Feng Jian Duan Pei-fei Qi You-chao Han Qi 《Applied Geophysics》 SCIE CSCD 2020年第5期639-648,899,共11页
Taking a study area in Jinzhong Basin in Qixian County,Shanxi Province,as an example,this work performs an intelligent interpretation of ground fissures.On the basis of a complete analysis of the regional geological b... Taking a study area in Jinzhong Basin in Qixian County,Shanxi Province,as an example,this work performs an intelligent interpretation of ground fissures.On the basis of a complete analysis of the regional geological background in the study area,dip-steering cube operation and median filtering of seismic data were performed using fast Fourier transform to improve the continuity of seismic events and eliminate random noise.A total of 200 stratigraphic continuous sample training points and 500 discontinuous training points were obtained from the processed seismic data.Thereafter,a variety of attributes(coherence,curvature,amplitude,frequency,etc.)were extracted as the input for the multilayer perceptron neural network training.During the training period,the training results were traced by normalized root mean square error(RMSE)and misclassifi cation.The training results showed a downward trend during the training period.The misclassifi cation curve was stable at 0.3,and the normalized RMSE curve was stable at 0.68.When the value of the normalized RMSE curve reached the minimum,the training was terminated,and the training results were extended to the whole data volume to obtain the attribute cube of intelligent ground fi ssure detection.The characteristics of ground fi ssures were analyzed and identifi ed from the sections and slices.A total of 11 ground fissures were finally interpreted.The interpretation results showed that the dip angles were 60°-85°,the fault throws were 0-43 m,and the extension lengths were 300-1,100 m in the whole area.The strike of 73%of the ground fi ssures was consistent with the direction of the regional tectonic settings.Specifi cally,four ground fi ssures coincided with the surface disclosed,and the verifi cation rate reached 100%.In conclusion,the intelligent ground fi ssure detection attribute based on the dip-steering cube is eff ective in predicting the spatial distribution of ground fi ssures. 展开更多
关键词 neural network ground fi ssures development area dip-steering cube intelligent ground fi ssure detection attribute
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A modeling method of semiconductor fabrication flows with extended knowledge hybrid Petri nets
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作者 周炳海 《High Technology Letters》 EI CAS 2008年第1期6-11,共6页
A modeling method of extended knowledge hybrid Petri nets (EKHPNs), incorporating object-oriented methods into hybrid Petri nets (HPNs), was presented and used for the representation ~d modeling of semiconductor w... A modeling method of extended knowledge hybrid Petri nets (EKHPNs), incorporating object-oriented methods into hybrid Petri nets (HPNs), was presented and used for the representation ~d modeling of semiconductor wafer fabrication flows. To model the discrete and continuous parts of a complex semiconductor wafer fabrication flow, the HPNs were introduced into the EKHPNs. Object-oriented methods were combined into the EKHPNs for coping with the complexity of the fabrication flow. Knowledge anno- tations were introduced to solve input and output conflicts of the EKHPNs. Finally, to demonstrate the validity of the EKHPN method, a real semiconductor wafer fabrication case was used to illustrate the model- ing procedure. The modeling results indicate that the proposed method can be used to model a complex semiconductor wafer fabrication flow expediently. 展开更多
关键词 semiconductor wafer fabrication KNOWLEDGE Petri nets object-oriented methods
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PMC推出业内集成度最高、功耗最低的射频收发器芯片组可用于下一代宏基站
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《计算机与网络》 2012年第11期74-74,共1页
致力于存储网络、光网络以及移动网络半导体解决方案创新的PMC公司(纳斯达克代码:PMCS)近日推出了专为下一代宏基站设计的业内集成度最高、功耗最低的射频收发器芯片组。PMC的新型UniTRX?芯片组可替代最多14个分立器件,为近似的多... 致力于存储网络、光网络以及移动网络半导体解决方案创新的PMC公司(纳斯达克代码:PMCS)近日推出了专为下一代宏基站设计的业内集成度最高、功耗最低的射频收发器芯片组。PMC的新型UniTRX?芯片组可替代最多14个分立器件,为近似的多标准基站的射频设计节省至少50%的电路板空间和功耗。该芯片组满足了多标准宏基站的性能需求。并简化了密集型MIMO(多人多出)无线电装置的设计.如有源天线系统。 展开更多
关键词 PMC 射频收发器芯片组 存储网络 移动网络导体
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Development of a Genetic Algorithm for Evaluating the Performance of Overhead Power Distribution Lines and Proposing Solutions to Improve Distribution Line Safety
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作者 Fabio Romero Alden U. Antunes +4 位作者 Dario Takahata Andre Meffe Carlos C. B. Oliveira Femando L. Lange Hamilton Souza 《Journal of Energy and Power Engineering》 2015年第1期78-82,共5页
This paper aims to present and discuss the use of a power flow methodology based on Gauss elimination method to evaluate the performance of distribution network taking into account the neutral conductor absence at spe... This paper aims to present and discuss the use of a power flow methodology based on Gauss elimination method to evaluate the performance of distribution network taking into account the neutral conductor absence at specific sections, and a development of a methodology based on GA (genetic algorithm) capable of evaluating alternative solutions in different bars of the feeder, in order to propose appropriate solutions to improve the distribution network safety. Besides the technical aspects, the proposed GA methodology takes into account the economic feasibility analysis. The results of power flow simulations have shown that the presence of single-phase transformers along with the absence of the neutral conductor at specific sections of the MV (medium voltage) network may increase the Vng (neutral-to-ground voltage) levels of the feeders involved, jeopardizing the system's safety. On the other hand, the solutions proposed by the GA methodology may reduce the network Vng levels and improve the safety conditions, providing values close to the ones found before the neutral conductor theft. 展开更多
关键词 Genetic algorithm power flow distribution line safety power flow simulation
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家庭网络半导体市场08年将达23亿美元
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《现代材料动态》 2004年第11期18-18,共1页
关键词 网络导体市场 市场调查 市场价格 以太网 同轴电缆传递多媒体 家庭娱乐服务器
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Novel Algorithm for Estimating the Distance of Open-Conductor Faults in HV Transmission Lines
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作者 Mahmoud Gilany Ahmed Al-Kandari Bahaa Hassan 《Journal of Energy and Power Engineering》 2012年第8期1301-1307,共7页
This paper presents an ANN (artificial neural networks)-based technique for improving the performance of distance relays against open-circuit faults in transmission networks. The technique utilizes the small capacit... This paper presents an ANN (artificial neural networks)-based technique for improving the performance of distance relays against open-circuit faults in transmission networks. The technique utilizes the small capacitive current measured in the open-phase plus the currents in the two healthy phases in calculating the open-circuit fault distance. The results obtained show that a distance relay with the proposed scheme will not only be able to detect the open-conductor condition in HVTL (high voltage transmission line) but also to locate the place of this fault regardless the value of the pre-fault current loading. There is no need for especial communication schemes since the existing media could work properly for the needs of the proposed technique. 展开更多
关键词 Distance relay open-conductor ANN transmission networks fault location.
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新型网络化制裁的结构性限制 被引量:11
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作者 吴限 《世界经济与政治》 CSSCI 北大核心 2022年第11期132-158,164,共28页
21世纪以来,新型网络化制裁成为一种新的外交强制形式,即通过将全球经济网状结构中的非对称相互依赖关系转换为强制性权力,进而迫使结构中的其他行为体与特定对象断开连接。尽管新型网络化制裁具有令人“谈虎色变”的威力,然而经验事实... 21世纪以来,新型网络化制裁成为一种新的外交强制形式,即通过将全球经济网状结构中的非对称相互依赖关系转换为强制性权力,进而迫使结构中的其他行为体与特定对象断开连接。尽管新型网络化制裁具有令人“谈虎色变”的威力,然而经验事实表明其使用频率仍低于传统制裁,且在不同情况下其制定与实施存在显著差异。为厘清哪些因素限制了新型网络化制裁的使用,作者基于社会网络分析和复合依赖型政治经济理论提出了围绕网络演化速率的结构性解释,即结构的外部形态特征与其内在适应度决定了结构演化的速率,进而构成了网络化制裁的滞后成本和掣肘因素。结构既是网络化制裁的权力基础,又是其制约条件。通过对美国在货币金融网络和半导体技术网络中的网络化制裁进行案例分析,可发现主导国领导人为了避免在其任期内推动结构快速演化,在层次相对单一、形态呈多中心且功能性受制裁影响较大的经济结构中会谨慎并克制地使用网络化制裁;而在层次相对复杂、形态呈单中心且功能性受制裁影响较小的结构中则频繁并激烈地使用网络化制裁。 展开更多
关键词 网络化制裁 货币金融网络 导体技术网络 结构演化 适应度
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Enhanced CMOS image sensor by flexible 3D nanocone anti-reflection film 被引量:2
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作者 Li Tian Xiaolei Luo +3 位作者 Min Yin Dongdong Li Xinzhong Xue Hui Wang 《Science Bulletin》 SCIE EI CAS CSCD 2017年第2期130-135,共6页
Complementary metal oxide semiconductor(CMOS) image sensors(CIS) are being widely used in digital video cameras, web cameras, digital single lens reflex camera(DSLR), smart phones and so on, owing to their high level ... Complementary metal oxide semiconductor(CMOS) image sensors(CIS) are being widely used in digital video cameras, web cameras, digital single lens reflex camera(DSLR), smart phones and so on, owing to their high level of integration, random accessibility, and low-power operation. It needs to be installed with the cover glass in practical applications to protect the sensor from damage, mechanical issues,and environmental conditions, which, however, limits the accuracy and usability of the sensor due to the reflection in the optical path from air-to-cover glass-to-air. In this work, the flexible 3D nanocone anti-reflection(AR) film with controlled aspect ratio was firstly employed to reduce the light reflection at air/cover glass/air interfaces by directly attaching onto the front and rear sides of the CIS cover glass.As both the front and rear sides of cover glass were coated by the AR film, the output image quality was found to be improved with external quantum efficiency increased by 7%, compared with that without AR film. The mean digital data value, root-mean-square contrast, and dynamic range are increased by45.14%, 38.61% and 57, respectively, for the output image with AR films. These results provide a novel and facile pathway to improve the CIS performance and also could be extended to rational design of other image sensors and optoelectronic devices. 展开更多
关键词 CMOS image sensor Nancone anti-reflection film Quantum efficiency Digital data value Root-mean-square contrast
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