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

中低速磁浮车空压机的选型

铁道车辆 2024年第2期62卷 84-88页

作者：秦东宾吴学瑞郭宗斌中车制动系统有限公司技术研发中心山东青岛266031

基于中低速磁浮车项目对空压机提出了新要求。首先对各种类型空压机的基本原理和优缺点进行定性分析,包括有油活塞式、无油活塞式、喷油螺杆式、滑片式和无油涡旋式;在此基础上对空压机的主要技术指标进行归纳,并将各技术指标采用数值... 详细信息

基于中低速磁浮车项目对空压机提出了新要求。首先对各种类型空压机的基本原理和优缺点进行定性分析,包括有油活塞式、无油活塞式、喷油螺杆式、滑片式和无油涡旋式;在此基础上对空压机的主要技术指标进行归纳,并将各技术指标采用数值化矩阵形式表达,各指标间综合评价赋权,从而可得到综合评价数学模型并据此选型;对空压机的电气控制逻辑进行了阐述,利用TCMS和备用压力开关实现对空压机的启停控制,并合理输出故障模式。综上可实现空压机的合理选型和规范化设计。

关键词：中低速磁浮空压机选型模型控制逻辑

基于GPS-IR的复杂寒区地表冻融状态监测研究

在线全文

学校读者我要写书评

暂无评论

地理空间信息 2024年第4期22卷 65-70页

作者：宋少辉吴学睿赵乐文南京信息工程大学遥感与测绘工程学院江苏南京210044 中国科学院上海天文台天文地球动力学研究中心上海200030

针对复杂寒区地表冻融状态情况,基于GPS-IR(Global Positioning System-Interference Reflectometry)技术进行地表冻融状态监测精度研究。采用2017—2022年PBO(The Plate Boundary Observatory)GPS站点数据,结合SNOTEL气象站地表实测数据,充分考虑了复杂寒区地表积雪深度、土壤湿度和地表冻融状态对GPS(Global Positioning System)多路径观测值的影响,基于GPS-IR技术利用卫星反射信号来进行地表冻融状态监测。结果表明:在积雪深度和土壤湿度时间序列平稳的状态下,GPS-IR技术的冻融监测精度为90.63%,积雪深度和土壤湿度的波动都会导致监测精度下降。实验表明GPS-IR技术的监测精度会受到积雪深度和土壤湿度的影响,在地球物理参数小范围变化的情况下监测精度较好,对地表冻融状态响应敏感,是一种有效监测复杂寒区冻融特性的有效手段。

关键词： GPS-IR 积雪深度土壤湿度地表冻融状态多路径观测值

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

向日葵种质资源的耐盐性评价

植物遗传资源学报 2024年第9期25卷 1480-1492页

作者：李玉骁汪磊汪魏李军邬雪瑞朱梓榕王玲吴佳俊谭美莲中国农业科学院油料作物研究所/农业农村部油料作物生物学与遗传育种重点实验室巴彦淖尔市农牧业科学研究院

为了解向日葵种质资源的耐盐性，鉴定发掘向日葵耐盐优异种质，对444份种质资源分别进行了芽期（250 mmol/L NaCl）、苗期（250 mmol/L NaCl）耐盐鉴定和盐碱地全生育期种植观察，通过测定芽期发芽率、苗期存活率、叶面积、株高、SPAD值... 详细信息

为了解向日葵种质资源的耐盐性，鉴定发掘向日葵耐盐优异种质，对444份种质资源分别进行了芽期（250 mmol/L NaCl）、苗期（250 mmol/L NaCl）耐盐鉴定和盐碱地全生育期种植观察，通过测定芽期发芽率、苗期存活率、叶面积、株高、SPAD值等6个苗期指标和全生育期株高、葵盘直径、结实率、相关产量等7个指标的相对值（各指标与对照处理的相应比值）进行耐盐性分析评价。相关性分析结果表明苗期两两指标间均呈极显著正相关，相关系数在0.518-0.790之间；全生育期7个指标中多数指标间的相关性都达到了显著或极显著水平。基于指标相对值进行主成分分析、隶属函数值计算、耐盐性综合评价和聚类分析，筛选出芽期耐盐及以上种质132份、苗期耐盐及以上种质9份、全生育期耐盐及以上种质41份，其中6份种质（ZX0365、ZX0389、ZX1391、ZX1394、ZX3089、ZX3094）在3个时期均表现为耐盐及以上等级，综合耐盐性好，可作为耐盐基因挖掘和耐盐品种选育等后续利用的种质材料。对其中124份种质3个时期（芽期、苗期、全生育期）的耐盐等级进行相关性分析，结果表明各时期的耐盐性鉴定结果极显著相关，芽期和苗期的耐盐鉴定结果可为盐碱地种植向日葵选择耐盐材料提供有效参考。本研究为向日葵耐盐品种选育提供了方法和材料基础。

关键词：向日葵芽期苗期全生育期耐盐性鉴定

Characteristics of the propagation of partial discharge ultrasonic signals on a transformer wall based on Sagnac interference

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2020年第2期22卷 10-18页

作者： Jun JIANG Kai WANG xuerui wu Guoming MA Chaohai ZHANG Jiangsu Key Laboratory of New Energy Generation and Power Conversion Nanjing University of Aeronautics and AstronauticsNanjing 211106People's Republic of China Department of Electrical&Electronic Engineering School of EngineeringThe University of ManchesterManchester Ml39PLUnited Kingdom State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206People's Republic of China

The acoustic emission(AE)method has been widely recognized for the detection of incipient insulation fault phenomenon(partial discharge,PD)in power transfomiers,nevertheless,the installation and placement of AE sensors should be taken into full *** this manuscript,a three-dimensional multiphysics model was established and simulated to research the characteristics of the propagation in the transformer ***,a piezoelectric transducer was used to detect PD ultrasonic signals and verify the simulation results in the *** ensure the accuracy of the detection,an optical fiber sensor based on the Sagnac interference principle was designed and *** variation of the amplitude of the ultrasonic signal with distance reveals the characteristics of the ultrasonic signal propagating in the transformer *** distribution of sound pressure on the upper and lower surfaces of the simulation model proved that ultrasonic waves propagate in the form of symmetrical Lamb waves in the transformer ***,the amplitude of the AE attenuates due to absorption and refraction loss,and local fluctuations on account of acoustic ***,a stable signal detected by an AE sensor does not represent the absence of PD in a *** improve the reliability of AE detection,it is proposed in this manuscript that repeated movement of the AE sensor is necessary to obtain a suitable measurement ***,it is necessary to adjust the position of the AE sensor in order to locate the PD source *** addition,this study is expected to provide a theoretical analysis and a fiber sensor to address the problem of sensor placement in AE detection.

关键词： partial discharge power transformer ultrasonic detection optical fiber Sagnac interference

Comparison of the Arctic upper-air temperatures from radiosonde and radio occultation observations

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2018年第1期37卷 30-39页

作者： CHANG Liang GUO Lixin FENG Guiping wu xuerui GAO Guoping ZHANG Yang ZHANG Yu College of Marine Sciences Shanghai Ocean University Key Laboratory of Planetary Sciences Chinese Academy of Sciences Collaborative Innovation Center for Distant-water Fisheries Shanghai Astronomical Observatory Chinese Academy of Sciences State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography State Oceanic Administration

The air temperature is one of the most important parameters used for monitoring the Arctic climate change. The constellation observing system for meteorology, ionosphere, and climate and Formosa Satellite Mission 3(COSMIC/FORMOSAT-3) radio occultation(RO) "wet" temperature product(i.e., "wet Prf") is used to analyze the Arctic air temperature profiles at 925–200 hPa in 2007–2012. The "wet" temperatures are further compared with radiosonde(RS) observations. The results from the spatially and temporally synchronized RS and COSMIC observations show that their temperatures agree well with each other, especially at 400 hPa. Comparisons of seasonal temperatures and anomalies from the COSMIC and homogenized RS observations suggest that the limited number of COSMIC observations during the spatial matchup may be insufficient to describe the smallscale spatial structure of temperature variations. Furthermore, comparisons of the seasonal temperature anomalies from the RS and 5°×5° gridded COSMIC observations at 400 hPa during the sea ice minimum(SIM) of2007 and 2012 are also made. The results reveal that similar Arctic temperature variation patterns can be obtained from both RS and COSMIC observations over the land area, while extra information can be further provided from the densely distributed COSMIC observations. Therefore, despite COSMIC observations being unsuitable to describe the Arctic temperatures in the lowest level, they provide a complementary data source to study the Arctic upper-air temperature variations and related climate change.

关键词： Arctic temperature radio occultation radiosonde

河套灌区中度盐碱地高垄覆膜滴灌对向日葵生长及水分利用的影响

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

作物杂志 2024年第1期 111-116页

作者：杜超李军王刚邬雪瑞任志远张俊峰包海柱温埃清巴彦淖尔市农牧业科学研究所内蒙古巴彦淖尔015000 内蒙古农业大学内蒙古呼和浩特010019

针对河套灌区土壤返盐积盐强烈,大量中度盐碱地向日葵生长势差以及生育后期的生理干旱胁迫导致的向日葵减产问题,开展了盐碱地高垄覆膜滴灌对向日葵生长和水分利用率及其产量影响的研究。结果表明,高垄覆膜滴灌种植模式有效提高了向日... 详细信息

针对河套灌区土壤返盐积盐强烈,大量中度盐碱地向日葵生长势差以及生育后期的生理干旱胁迫导致的向日葵减产问题,开展了盐碱地高垄覆膜滴灌对向日葵生长和水分利用率及其产量影响的研究。结果表明,高垄覆膜滴灌种植模式有效提高了向日葵叶面积指数,开花期增幅最大,较平作覆膜滴灌(CK1)和平作覆膜不灌(CK2)分别增加31.56%和75.28%,促进了地上部分干物质积累,灌浆期增幅最大,较CK1和CK2分别增加35.03%和100.62%;促进了根系生长,开花期根系鲜重较CK1和CK2分别增加71.86%和199.23%;有效提高了开花期和灌浆期0~30 cm土壤含水量,灌浆期增幅最大,较CK1和CK2分别增加7.51%和21.77%;提高了水分利用效率,较CK1和CK2分别增加21.20%和42.34%;较CK1和CK2增产分别为15.70%和28.31%,增产效果显著。综上表明,高垄覆膜滴灌模式在向日葵生长后期有明显的保墒效应,促进了干物质积累,从而增产,是盐碱地向日葵的适宜种植模式。

关键词：向日葵盐碱地高垄覆膜滴灌

Simulations and Analysis of BeiDou Navigation Satellite System （BDS）-Relectometry Delay-Doppler Maps for Vegetation

在线全文

学校读者我要写书评

暂无评论

Simulations and Analysis of BeiDou Navigation Satellite Syst...

Bare soil freeze/thaw process detection using GNSS-R/IR techniques: A case study in Alaska, USA

第五届中国卫星导航学术年会

作者： xuerui wu Shuanggen Jin Shanghai Astronomical Observatory Chinese Academy of Sciences Department of Environment Resources and Management Chifeng University

ISBN: (纸本)9783642547362

Global Positioning System-Reflectometry （GPS-R） is a new promising technique, which uses the reflected signals of the GPS constellation to remotely sense the geophysical parameters of the ocean and land surface. Some initial results were obtained from GPS-R in ocean surface characteristics and soil moisture, while, vegetation sensing is paid attention recently. With the development of Chinese independent Beidou Satellite Navigation System （BDS）, it will play a key role in positioning, navigation and timing as well as potential applications of BDS-Reflectometry （BDS-R）, e.g. vegetation monitoring using the Delay-Doppler Map（DDM） of BDS-R. Therefore, it is extremely necessary to simulate the vegetation BDS-R DDM maps. Z-V model is a commonly used GPS-R scattering model and its applications include the sea wind, oil slick and soil moisture. In this paper, it is the first time for vegetation DDM simulations from BDS-R, while the vegetation scattering properties are simulated using the modified Bi-mimics model, which can be used to calculate any transmit and receive polarization combinations, assuming that the received power is coming from the first Fresnel zone. The theoretical simulations of DDM are helpful for the further BDS-R vegetation parameters retrieval, and some discussions and analysis are further given.

关键词： BDS‐R vegetation Z‐V Bi‐mimics DDM

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

Bare soil freeze/thaw process detection using GNSS-R/IR tech...

第十一届中国卫星导航年会

作者： xuerui wu Sharula Xuanran Li Lei Yang School of Information Science and Engineering Shandong Agricultural University Shanghai Astronomical Observatory Chinese Academy of Sciences Key Laboratory of space navigation and position technology Key Laboratory of Planetary Sciences Chinese Academy of Sciences

GNSS-IR is a new emerging remote sensing technique, and it utilizes the interference signal of direct and reflected signals for geophysical parameters retrieval. Nowadays, its application include soil

关键词： GNSS-IR soil freeze/thaw process dielectric constant multipath

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

中西医治疗脊髓损伤神经源性膀胱的研究进展

实用中医内科杂志 2024年第1期38卷 71-74页

作者：王海婷张丽平可易弘武雪瑞包利红张芳方颖宋淑华甘肃中医药大学甘肃兰州730000 甘肃省中医院甘肃兰州730050

脊髓损伤多由外伤引起,其中并发症以神经源性膀胱多见,从而导致膀胱功能受损,并发泌尿系感染,甚至发展为尿毒症,进而危及生命。文章从中医和西医两方面切入,总结目前中西医治疗脊髓损伤后神经源性膀胱的措施,分析各自的优势和不足,为临... 详细信息

脊髓损伤多由外伤引起,其中并发症以神经源性膀胱多见,从而导致膀胱功能受损,并发泌尿系感染,甚至发展为尿毒症,进而危及生命。文章从中医和西医两方面切入,总结目前中西医治疗脊髓损伤后神经源性膀胱的措施,分析各自的优势和不足,为临床提供最佳的治疗方案。

关键词：脊髓损伤神经源性膀胱中西医治疗综述