期刊文献+
共找到10篇文章
< 1 >
每页显示 20 50 100
Why would sea-level rise for global warming and polar ice-melt?
1
作者 Aftab Alam Khan 《Geoscience Frontiers》 SCIE CAS CSCD 2019年第2期481-494,共14页
Two major causes of global sea level rise such as thermal expansion of the oceans and the loss of landbased ice for increased melting have been claimed by some researchers and recognized by the IPCC.However, other cli... Two major causes of global sea level rise such as thermal expansion of the oceans and the loss of landbased ice for increased melting have been claimed by some researchers and recognized by the IPCC.However, other climate threat investigators revealed that atmosphere-ocean modeling is an imperfect representation, paleo-data consist of proxy climate information with ambiguities, and modern observations are limited in scope and accuracy. It is revealed that global warming and polar ice-melt although a reality would not contribute to any sea level rise. Floating-ice of the polar region on melting would reoccupy same displaced volume by floating ice-sheets. Land-ice cover in the polar region on melting can reduce load from the crust to activate elastic rebound that would raise land for its isostatic equilibrium.Such characteristics would not contribute to sea level rise. Equatorial bulge, polar flattening, elevation difference of the spheroidal surface between equator and pole with lower in the pole, strong gravity attraction of the polar region and week gravity attraction of the equatorial region, all these phenomena would play dominant role in preventing sea level rise. Palaeo-sea level rise and fall in macro-scale(10-100 m or so) were related to marine transgression and regression in addition to other geologic events like converging and diverging plate tectonics, orogenic uplift of the collision margin, basin subsidence of the extensional crust, volcanic activities in the oceanic region, prograding delta buildup, ocean floor height change and sub-marine mass avalanche. This study also reveals that geophysical shape, gravity attraction and the centrifugal force of spinning and rotation of the earth would continue acting against sea level rise. 展开更多
关键词 Global warming Polar ice-melt Equatorial bulge Polar flattening Geologic events Sea level rise
下载PDF
土壤结构对流入变压器中性点直流电流的影响 被引量:53
2
作者 何俊佳 叶会生 +3 位作者 林福昌 李化 卢毓欣 桂重 《中国电机工程学报》 EI CSCD 北大核心 2007年第36期14-18,共5页
当直流输电系统单极大地回路运行时,会在直流接地极附近的中性点接地变压器中流过较大直流电流,从而导致变压器直流偏磁等一系列后果。采用复合分层土壤结构模型,基于特定的计算模型,对直流接地极流入直流电流时引起的地中电流场分布和... 当直流输电系统单极大地回路运行时,会在直流接地极附近的中性点接地变压器中流过较大直流电流,从而导致变压器直流偏磁等一系列后果。采用复合分层土壤结构模型,基于特定的计算模型,对直流接地极流入直流电流时引起的地中电流场分布和地电位分布进行计算,分析流入变压器中性点的直流电流。同时通过改变土壤结构模型参数,分析不同土壤结构配置下流入变压器中性点直流电流的变化。研究表明,土壤结构对流入变压器中性点的直流电流影响较大,因此在精确计算流入变压器中性点的直流电流时应考虑土壤情况的复杂性。研究结果为实际工程中直流接地极附近变电站选址提供理论参考。 展开更多
关键词 高压直流 中性点直流电流 土壤结构
下载PDF
溪浙特高压直流隔直装置存在的问题分析及改进 被引量:21
3
作者 王华伟 林少伯 +7 位作者 王祖力 王明新 黄勇 雷霄 王庆 李新年 王亮 孙栩 《电网技术》 EI CSCD 北大核心 2015年第6期1600-1604,共5页
特高压直流换流变压器中性点在各种操作及运行时谐波含量远高于交流变电站,在安装隔直装置解决直流偏磁现象时需要考虑的因素更多。首套安装在特高压直流换流站的直流偏磁装置在直流系统调试中出现了不恰当投切、频繁投切等较多不适应... 特高压直流换流变压器中性点在各种操作及运行时谐波含量远高于交流变电站,在安装隔直装置解决直流偏磁现象时需要考虑的因素更多。首套安装在特高压直流换流站的直流偏磁装置在直流系统调试中出现了不恰当投切、频繁投切等较多不适应直流运行工况的问题,针对其由于退出隔直功能的保护定值较小引起的不恰当投切、频繁投切问题,结合现场录波波形和直流系统运行工况进行了分析和研究,提出了修改投入隔直功能的延时时间,增大退出隔直功能的保护定值的改进措施解决不恰当投切和频繁投切问题,并在直流系统运行中加以应用,所得结论对后续直流工程的换流变加装隔直装置的工程应用具有一定的指导意义。 展开更多
关键词 特高压直流输电 直流偏磁 隔直装置 换流变压器 饱和保护
下载PDF
化冰盐对灾后长沙城市森林植物的危害 被引量:7
4
作者 吴际友 侯伯鑫 +2 位作者 王旭军 廖德志 程勇 《中国城市林业》 2008年第2期6-9,共4页
2008年1月中旬至2月初,50年以来罕见的严重冰冻灾害,对长沙城市森林植物损害巨大[1]。抗冰救灾期间,为保交通,对市区范围"6纵15横"共21条主干道进行撒盐融冰,据有关部门统计,至2月4日,累计抛撒工业用盐近7000t,日均撒盐量达60... 2008年1月中旬至2月初,50年以来罕见的严重冰冻灾害,对长沙城市森林植物损害巨大[1]。抗冰救灾期间,为保交通,对市区范围"6纵15横"共21条主干道进行撒盐融冰,据有关部门统计,至2月4日,累计抛撒工业用盐近7000t,日均撒盐量达600t[2-3]。大量使用工业盐或氯盐类融雪剂化冰,对桥梁、公路及植物等产生的次生灾害国内外己有深刻的教训。为此,我们对长沙市主干道绿化带进行了跟踪调查,发现目前大面积花灌木死亡或生长不良的主要原因除遭受严重冻害之外,渗入绿化带土壤中的盐分已使土壤出现不同程度的盐碱化,对适宜酸性土生长的本土植物构成了不可低估的生态灾害。本文旨在为长沙城市森林灾后重建工作提出解决途径。 展开更多
关键词 ice-melt Salt Soil basification Landscape plant Changsha city
下载PDF
电网过电流融冰运行方式可行性研究 被引量:15
5
作者 张文朝 韩奕 +4 位作者 徐友平 张东霞 胡学浩 宋军英 谌艳红 《电网技术》 EI CSCD 北大核心 2009年第20期54-58,共5页
针对2008年我国南部地区大范围冰灾对电网正常供电的影响,研究了通过调整运行方式达到输电线路融冰的可行性。通过调整湖南、江西电网的运行方式,对其电厂出线、主要输电断面和负荷中心线路进行过电流融冰可行性分析,结果表明,接入220 k... 针对2008年我国南部地区大范围冰灾对电网正常供电的影响,研究了通过调整运行方式达到输电线路融冰的可行性。通过调整湖南、江西电网的运行方式,对其电厂出线、主要输电断面和负荷中心线路进行过电流融冰可行性分析,结果表明,接入220 kV电压等级的电厂出线部分实施过电流融冰可行,负荷中心环网不具备过电流融冰的可行性,负荷馈线和省内主要断面实施过电流融冰的可行性很小。文中还探讨了短路电流融冰方案的适用范围。 展开更多
关键词 运行方式 过电流融冰 短路电流融冰 直流融冰 最小融冰电流
下载PDF
基于单片机的数控直流电流源设计与实现 被引量:15
6
作者 赵东波 郭荣幸 赵雨斌 《仪表技术》 2008年第6期58-60,共3页
介绍利用单片机系统、D/A与A/D转换器和恒流源电路实现输出范围为20~2000mA的数控直流电流源的设计,文中给出了数控直流电流源设计框图和主要电路。采用负反馈闭环控制系统,提高了电流源的输出精度。经测试表明,所设计的电流源具... 介绍利用单片机系统、D/A与A/D转换器和恒流源电路实现输出范围为20~2000mA的数控直流电流源的设计,文中给出了数控直流电流源设计框图和主要电路。采用负反馈闭环控制系统,提高了电流源的输出精度。经测试表明,所设计的电流源具有性能可靠、精度高的优点。 展开更多
关键词 单片机系统 D/A转换器 恒流源 数控电流源
下载PDF
Applicability of Air Bubbler Lines for Ice Control in Harbours 被引量:4
7
作者 潘华辰 Esa ERANTIb 《China Ocean Engineering》 SCIE EI 2007年第2期215-224,共10页
Ice formation in the harbours in arctic region such as in Finland is a problem in winter times. The air bubblers are often used for controlling the growth of ice near the harbour pier walls. This paper gives an in-dep... Ice formation in the harbours in arctic region such as in Finland is a problem in winter times. The air bubblers are often used for controlling the growth of ice near the harbour pier walls. This paper gives an in-depth description of the harbour ice problem and the applicability of the bubblers. A numerical method of flow and heat-transfer is used to predict the effectiveness of the air bubblers in controlling the ice accumulation in the harbours. Empirical models of formatting and melting the ice are presented and used in the numerical solutions. It shows that the numerical method can realistically predict the ice-melting effect of the air bubblers. 展开更多
关键词 ice-melting HARBOUR bubbler heat transfer
下载PDF
Decomposition behaviors of methane hydrate in porous media below the ice melting point by depressurization 被引量:2
8
作者 Yu Zhang Tian Wang +3 位作者 Xiaosen Li Kefeng Yan Yi Wang Zhaoyang Chen 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2019年第9期2207-2212,共6页
The decomposition behaviors of methane hydrate below the ice melting point in porous media with different particle size and different pore size were studied.The silica gels with the particle size of 105–150μm,150–... The decomposition behaviors of methane hydrate below the ice melting point in porous media with different particle size and different pore size were studied.The silica gels with the particle size of 105–150μm,150–200μm and 300–450μm,and the mean pore diameters of 12.95 nm,17.96 nm and 33.20 nm were used in the experiments.Methane recovery and temperature change curves were determined for each experiment.The hydrate decomposition process in the experiments can be divided into the depressurization period and the isobaric period.The temperature in the system decreases quickly in the depressurization process with the hydrate decomposition and reaches the lowest point in the isobaric period.The hydrate decomposition in porous media below ice-melting point is very fast and no self-perseveration effect is observed.The hydrate decomposition is influenced both by the driving force and the initial hydrate saturation.In the experiments with the high hydrate saturation,the hydrate decomposition will stop when the pressure reaches the equilibrium dissociation pressure.The stable pressure in the experiment with high hydrate saturation exceeds the equilibrium dissociation pressure of bulk hydrate and increases with the decrease of the pore size. 展开更多
关键词 METHANE HYDRATE DEPRESSURIZATION POROUS media Decomposition ice-melting point
下载PDF
Laterally Sandwich-typed Hydrogel Columns with Liner Poly(N-isopropylacrylamide) Layer:Preparation, Swelling/deswelling Kinetics and Drug Delivery Characteristics
9
作者 LI Ying XIAO Xincai 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2012年第1期115-119,共5页
A novel thermo-responsive hydrogel column, featured with both ends of linear poly(N- isopropylacrylarnide) (PNIPAM) chains being grafted onto cross-linked PNIPAM chains, was reported. The laterally sandwich-typed ... A novel thermo-responsive hydrogel column, featured with both ends of linear poly(N- isopropylacrylarnide) (PNIPAM) chains being grafted onto cross-linked PNIPAM chains, was reported. The laterally sandwich-typed hydrogel columns were fabricated by radical polymerization in a three-step process using a method of ice-melting synthesis. The initiating path, morphology and thermoresponsive characteristics of the prepared hydrogel columns were experimentally studied. The results show that the hydrogel column obtained by the initiator inside part has more quick swelling and deswelling rates responsing to temperature cycling than other hydrogels owing to linear PNIPAM chains to form supermacroporous structure. The proposed hydrogel structure provide a new mode of the phase transition behavior for thermo-sensitive "smart" or "intelligent" monodisperse micro-actuators, which is highly attractive for targeting drug delivery systems, chemical separations, and sensors and so on. 展开更多
关键词 ice-melting synthesis laterally sandwich-typed hydrogel columns swelling/de-swellingrates poly(N-isopropylacrylamide)
下载PDF
30万t/a离子膜法烧碱整流机组参数的确定
10
作者 孙利俊 耿庆鲁 《氯碱工业》 CAS 2018年第9期6-8,11,共4页
以30万t/a离子膜法烧碱装置采用国产2. 5万t/a离子膜电解装置为例进行设定,整流机组参数的确定包括一次侧电压、直流电压、直流电流、机组数量、等效整流相数,整流柜参数、导电排参数等。
关键词 离子膜法烧碱 整流变压器 整流柜 直流电压 直流电流 整流相数
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部