检索结果-南通市图书馆

Improvement of Boxcar Integrator and Its Application to Low Resistance Measurement of Inductive Load Coil

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1998年第3期12卷 180-184页

作者： xisheng li Shaochun Wang(Information Engineering School, University of Science and Technology Beijing, Beijing 100083, China) Information Engineering School University of Science and Technology Beijing Beijing 100083 China

A boxcar integrator is described which is suitable for the low-repetition-rate signal processing. This boxcar integrator, named fixed-interval mode boxcar integrator, is able to reject harmonics other than the first harmonic component. It can also decrease the effective time constant In many situations, the antialiasing filter with narrow bandwidth will cause distortion of the input signal. The fixed-interval mode boxcar integrator with suitable gate width can achieve relative high performance without signal distortion because the bandwidth of its antialiasing filter can be wider than that in the fixed-Point boxcar integrator. ms boxcar integrator is used as majn part of signalprocessing circult in the low resisance measurement of inductive load coil. The results of experiments show that the fixed-interval boxcar integrator is suitable for low-repetition-rate use.

关键词： signal processing resistance measurement boxcar integrator

Remnants and fragments of the subducted paleo-Pacific plate:Constraints from geochemistry and geophysics

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第10期67卷 3041-3061页

作者： xisheng XU Zhouchuan HUANG Dingsheng JIANG Gang ZENG li-Qun DAI State Key Laboratory for Mineral Deposits Research School of Earth Sciences and EngineeringNanjing UniversityNanjing 210023China School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China

The subduction and rollback of the paleo-Pacific plate during Mesozoic time was the key engine for the evolution of the continental margin in eastern China. It led to lateral accretion of continental crust in Northeast China, lithospheric destruction beneath the North China Craton, and the generation of huge volumes of felsic magmatic rocks in South China. This had a profound influence on deep material cycles and the evolution of epigenetic environmental systems along the continental margin of East Asia. To fully understand the transformation of the dynamic mechanism during the subduction and rollback of the paleoPacific plate, we have attempted to trace the remnants and fragments of the subducted paleo-Pacific plate at great depths. Such remnants in both temporal and spatial dimensions can be tracked by using geochemical and geophysical approaches. Studies of the trace elements, Mg-Zn isotopes and Os-Nd-Hf-Pb-O isotopes in continental basalts from eastern China reveal a significant number of the remnants of subduction of the paleo-Pacific plate, and the initial subduction can be traced back to the Early Jurassic. Large-scale geophysical imaging unveils a multitude of high-velocity anomalies in the lower mantle of East ***, many high-velocity bodies, aptly referred to as “slab graveyards”, are nestled at the base of the lower mantle. Numerous isolated high-velocity anomalies are also present in the upper part of the lower mantle, creating conduits for the descent of the subducted slabs into the lower mantle. However, a resolution of the remnants for the subducted slabs within the lower mantle are quite low. Consequently, their impact on the lower mantle's dynamics is yet to be thoroughly investigated. Finally, the presently observed big mantle wedge(BMW) in East Asia has developed through subduction of the Pacific plate in the ***, following the rollback of the paleo-Pacific plate(began at ~145 Ma), a Cretaceous BMW system would also form above

关键词： Paleo-Pacific plate Big mantle wedge Late Mesozoic Remnants and fragments Geochemistry Geophysics

Terrain or climate factor dominates vegetation resilience?Evidence from three national parks across different climatic zones in China

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2024年第4期11卷 526-542页

作者： Shuang liu lingxin Wu Shiyong Zhen Qinxian lin xisheng Hu Jian li College of Transportation and Civil Engineering Fujian Agriculture and Forestry UniversityFuzhou 350002China College of JunCao Science and Ecology Fujian Agriculture and Forestry UniversityFuzhou 350002China College of Forestry Fujian Agriculture and Forestry UniversityFuzhou 350002China

Vegetation resilience(VR),providing an objective measure of ecosystem health,has received considerable attention,however,there is still limited understanding of whether the dominant factors differ across different climate *** took the three national parks(Hainan Tropical Rainforest National Park,HTR;Wuyishan National Park,WYS;and Northeast Tiger and Leopard National Park,NTL)of China with less human interference as cases,which are distributed in different climatic zones,including tropical,subtropical and temperate monsoon climates,***,we employed the probabilistic decay method to explore the spatio-temporal changes in the VR and their natural driving patterns using Geographically Weighted Regression(GWR)model as *** results revealed that:(1)from 2000 to 2020,the Normalized Difference Vegetation Index(NDVI)of the three national parks fluctuated between 0.800 and 0.960,exhibiting an overall upward trend,with the mean NDVI of NTL(0.923)>HTR(0.899)>WYS(0.823);(2)the positive trend decay time of vegetation exceeded that of negative trend,indicating vegetation gradual recovery of the three national parks since 2012;(3)the VR of HTR was primarily influenced by elevation,aspect,average annual temperature change(AATC),and average annual precipitation change(AAPC);the WYS'VR was mainly affected by elevation,average annual precipitation(AAP),and AAPC;while the terrain factors(elevation and slope)were the main driving factors of VR in NTL;(4)among the main factors influencing the VR changes,the AAPC had the highest proportion in HTR(66.7%),and the AAP occupied the largest area proportion in WYS(80.4%).While in NTL,elevation served as the main driving factor for the VR,encompassing 64.2%of its ***,our findings indicated that precipitation factors were the main driving force for the VR changes in HTR and WYS national parks,while elevation was the main factors that drove the VR in *** research has promoted a deeper understanding of the dri

关键词： National parks Vegetation resilience NDVI Probabilistic decay model Driving factors

在线全文

学校读者我要写书评

暂无评论

两种药剂组合防治多斑柞跳象的田间药效试验

北方蚕业 2024年第1期45卷 18-20页

作者：赵世文赵鸿宇崔国杰韩冰穆秀奇沈金宇李喜升辽宁省蚕业科学研究所辽宁凤城118100

为有效防控柞园害虫多斑柞跳象,在小区试验基础上进行田间药效试验。结果表明,“蚕敌一扫光+乐果”对潜叶幼虫有较好的防效,可达90%左右;“敌克+敌克1号”“蚕敌一扫光+乐果”对当代成虫均有较好的防效。柞园防治多斑柞跳象可根据柞园... 详细信息

为有效防控柞园害虫多斑柞跳象,在小区试验基础上进行田间药效试验。结果表明,“蚕敌一扫光+乐果”对潜叶幼虫有较好的防效,可达90%左右;“敌克+敌克1号”“蚕敌一扫光+乐果”对当代成虫均有较好的防效。柞园防治多斑柞跳象可根据柞园实际情况选择药剂组合,潜叶幼虫期无蚕柞园推荐使用“蚕敌一扫光+乐果”组合;当代成虫期无蚕柞园用“蚕敌一扫光+乐果”,有蚕柞园用“敌克+敌克1号”进行防治。

关键词：药剂组合多斑柞跳象田间防效

深化监管机构改革推进市场监管现代化--以杭州市为例

在线全文

学校读者我要写书评

暂无评论

中国行政管理 2018年第8期 21-29页

作者：薛澜李希盛清华大学公共管理学院北京100871 清华大学公共管理学院MPA 北京100032

自2013年起,工商、质监、食药等市场监管部门经历了建国以来规模最大、为期最长、争议最多的新一轮机构改革。相关中央政策目标多元;各地自发探索了多种机构改革模式,同时"下改上不改"与"左右不同样"引发混乱;学术研究方兴未艾但缺乏系... 详细信息

自2013年起,工商、质监、食药等市场监管部门经历了建国以来规模最大、为期最长、争议最多的新一轮机构改革。相关中央政策目标多元;各地自发探索了多种机构改革模式,同时"下改上不改"与"左右不同样"引发混乱;学术研究方兴未艾但缺乏系统全面的实证分析。2018年,《深化党和国家机构改革方案》在顶层设计层面一锤定音,将原工商总局、质检总局、食药总局及国家发改委、商务部的反垄断职责等整合,组建国家市场监督管理总局。为此,本文聚焦政府职能转变、监管模式升级、组织架构优化三个研究维度,在梳理五年来中央政策和各地实践基础上,选择三合一、分级管理模式的杭州作为样本,重点评估其成效与不足,提炼对新市场监管体系的启示。本文建议,在三合一作为市场监管机构改革最大公约数的基础上,深化综合执法、平衡条块关系,以期统筹各项政策目标,推动市场监管体系现代化。

关键词：市场监管机构改革社会共治综合执法条块关系

Optimal operation of Internet Data Center with PV and energy storage type of UPS clusters

在线全文

学校读者我要写书评

暂无评论

Global Energy Interconnection 2024年第1期7卷 61-70页

作者： Man Chen Yuxin Zhao Yuxuan li Peng Peng xisheng Tang CSG PGC Energy Storage Research Institute Guangzhou 510000P.R.China Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190P.R.China University of Chinese Academy of Sciences Beijing 100049P.R.China

With the development of green data centers,a large number of Uninterruptible Power Supply(UPS)resources in Internet Data Center(IDC)are becoming idle assets owing to their low utilization *** revitalization of these idle UPS resources is an urgent problem that must be *** on the energy storage type of the UPS(EUPS)and using renewable sources,a solution for IDCs is proposed in this ***,an EUPS cluster classification method based on the concept of shared mechanism niche(CSMN)was proposed to effectively solve the EUPS control ***,the classified EUPS aggregation unit was used to determine the optimal operation of the *** IDC cost minimization optimization model was established,and the Quantum Particle Swarm Optimization(QPSO)algorithm was ***,the economy and effectiveness of the three-tier optimization framework and model were verified through three case studies.

关键词： Three-tier optimization framework Energy storage type of the UPS EUPS cluster classification method Quantum Particle Swarm Optimization

南海东部滚动背斜速度变化特征及勘探、开发启示

在线全文

学校读者我要写书评

暂无评论

石油地球物理勘探 2021年第5期56卷 1105-1116,I0013页

作者：刘振李黎李伟沈水荣李熙盛王要森中海石油(中国)有限公司深圳分公司广东深圳518041

南海东部滚动背斜普遍存在相似的时、深域构造差异特征,即“深度域构造近断层位置加深、远离断层位置抬升及深度高点相对时间高点远离断层”的构造变化特征,这种特征使构造预测存在较大误差,并成倍地影响油气藏资源量评价。上述时、深... 详细信息

南海东部滚动背斜普遍存在相似的时、深域构造差异特征,即“深度域构造近断层位置加深、远离断层位置抬升及深度高点相对时间高点远离断层”的构造变化特征,这种特征使构造预测存在较大误差,并成倍地影响油气藏资源量评价。上述时、深域构造差异特征来源于远离主断层上盘地层速度的快速减小。基于此认识,利用油田的钻探数据研究了背斜的速度变化规律,进一步提出沿层平均速度趋势法和梯度约束速度建模方法,获得以下认识:①速度梯度对油藏构造评估的影响较大,单井、常速度对构造的控制作用有限;②井点平均速度对构造评价影响较小;③研究区同类背斜速度变化与断层、埋深及位置有关;④局部范围内速度梯度与断距、埋深呈正比,与高点距断层的距离呈反比;⑤地震资料高点往往是探井优选的位置,对于滚动背斜构造,若仅钻探“时间高点”,可能会误判含油气构造,有必要进一步评价。应用所提方法成功推动了LF-C油田剩余油挖潜,并有效评估了HZ-D含油构造的储量潜力,促进了油气田的勘探和开发。

关键词：滚动背斜构造变化速度梯度时深转换剩余油挖潜

在线全文

学校读者我要写书评

暂无评论

一种陀螺与罗盘组合导航系统的故障检测方法

仪器仪表学报 2015年第10期36卷 2381-2388页

作者：冯毅博李希胜张晓娟北京科技大学自动化学院北京100083

为了提高MEMS陀螺和磁罗盘组合导航系统的可靠性,减少各种干扰和故障对导航精度的影响,提出了一种及时、精确、有效的故障检测方法。该方法首先对正常工作时的MEMS陀螺和磁罗盘信号中的各种噪声进行分析;然后针对组合系统中的常见故障,... 详细信息

为了提高MEMS陀螺和磁罗盘组合导航系统的可靠性,减少各种干扰和故障对导航精度的影响,提出了一种及时、精确、有效的故障检测方法。该方法首先对正常工作时的MEMS陀螺和磁罗盘信号中的各种噪声进行分析;然后针对组合系统中的常见故障,从陀螺和磁罗盘航向信息中提取出短时间内两者航向变化量差值的均值、均值的一阶差分量及二阶差分量作为故障检测量,用以区分识别不同的故障源;最后使用预警模式,来减小故障检测过程中的延迟影响,提高故障检测的及时性。实验结果表明,此方法可以及时、准确地区分识别出组合系统中零偏、速率斜坡故障以及两种磁干扰,有效地降低了干扰和故障的引入误差。

关键词：组合导航系统故障检测零偏误差速率斜坡磁场干扰

在线全文

学校读者我要写书评

暂无评论

一种电子磁罗盘航向误差的自适应补偿方法

仪器仪表学报 2014年第11期35卷 2607-2614页

作者：冯毅博李希胜张晓娟北京科技大学自动化学院北京100083

分析软硬磁干扰对磁罗盘航向角的影响,建立相应的磁罗盘航向误差模型,并将模型参数作为卡尔曼滤波器的状态量,在MIMU的辅助作用下,使模型参数随周围磁场环境变化而改变,增强了磁罗盘航向测量的环境适应性。卡尔曼滤波器的观测量分为常... 详细信息

分析软硬磁干扰对磁罗盘航向角的影响,建立相应的磁罗盘航向误差模型,并将模型参数作为卡尔曼滤波器的状态量,在MIMU的辅助作用下,使模型参数随周围磁场环境变化而改变,增强了磁罗盘航向测量的环境适应性。卡尔曼滤波器的观测量分为常规观测量和机动观测量,机动观测量在估计航向误差模型参数时增加了当前航向的权值,提高了当前航向的误差补偿精度。实验数据表明,在干扰磁场较强且人为改变干扰磁场的情况下,最大航向误差为±14.5°,经过自适应补偿后降至±0.2°以内。本算法可以精确地、自适应地对磁罗盘航向误差进行补偿,非常适合在周围磁场易变化的环境中使用。

关键词：电子磁罗盘航向误差卡尔曼滤波器自适应补偿