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A Study into Blood Flow, Heart Rate Variability, and Body Surface Temperature While Listening to Music 被引量:1
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作者 Kenichi Itao Makoto Komazawa Hiroyuki Kobayashi 《Health》 2018年第2期181-188,共8页
In this study we examined the relaxing effects of listening to music on a total of 12 women aged from their 20s to their 40s by measuring their blood flow, heart rate variability, and their body surface temperature. A... In this study we examined the relaxing effects of listening to music on a total of 12 women aged from their 20s to their 40s by measuring their blood flow, heart rate variability, and their body surface temperature. As a result, We found that there was a tendency for the volume of blood flow to the fingertips to significantly increase when listening to classical music, but there was a variety of changes in blood flow between each age group for healing music and J-Pop music. When measuring heart rate it was found that the LF/HF value, which is an index for the autonomic nervous system which shows tension and stress, fell significantly when listening to each type of music. Lastly, there was a trend for body surface temperature to rise when listening to classical or healing music, a rise which was particularly significant when listening to healing music. This study shows that a relaxing effect can be expected for all indices when listening to classical music. However, for healing music and J-Pop, personal musical preferences seemed to have an effect and the results were varied. 展开更多
关键词 Music BLOOD flow HEART rate Variability AUTONOMIC Nervous System Body surface TEMPERATURE
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Field Measurements of Influence of Sand Transport Rate on Structure of Wind-sand Flow over Coastal Transverse Ridge 被引量:10
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作者 DONG Yuxiang S L NAMIKAS +1 位作者 P A HESP MA Jun 《Chinese Geographical Science》 SCIE CSCD 2008年第3期255-261,共7页
The structure of wind-sand flow under different total sand transport rates was measured with field vertical anemometer and sand trap on the crest of typical coastal transverse ridge in Changli Gold Coast of Hebei Prov... The structure of wind-sand flow under different total sand transport rates was measured with field vertical anemometer and sand trap on the crest of typical coastal transverse ridge in Changli Gold Coast of Hebei Province, which is one of the most typical coastal aeolian distribution regions in China and famous for the tall and typical coastal transverse ridges. The measurement results show that, on the conditions of approximate wind velocities and same surface materials and environments, some changes happen to the structure of wind-sand flow with the increase of total sand transport rate on the crest of coastal transverse ridge. First, the sand transport rates of layers at different heights in the wind-sand flow increase, with the maximum increase at the height layer of 4-8cm. Second, the ratios of sand trans-port rates of layers at different heights to total sand transport rate decrease at the low height layer (0-4cm), but increase at the high height layer (4-60cm). Third, the distribution of the sand transport rate in the wind-sand flow can be expressed by an exponential function at the height layer of 0-40cm, but it changes from power function model to ex-ponential function model in the whole height layer (0-60cm) and changes into polynomial function model at the height layer of 40-60cm with the increase of total sand transport rate. Those changes have a close relationship with the limit of sand grain size of wind flow transporting and composition of sand grain size in the wind-sand flow. 展开更多
关键词 现场测量 输沙率 海岸横垄 风沙流的结构
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A New Method for Measurement of Helium Mass Flow Rate in the Cryogenic System of TORE SUPRA
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作者 欧阳峥嵘 Pascal Reynaud 《Plasma Science and Technology》 SCIE EI CAS CSCD 2005年第3期2825-2827,共3页
The TORE SUPRA Tokamak was built by EURATOM-CEA association. The NbTi conductor of superconducting coils is inserted in a tight enclosure filled with pressurized superfluid helium of 0.125 MPa at 1.8 K. The thick casi... The TORE SUPRA Tokamak was built by EURATOM-CEA association. The NbTi conductor of superconducting coils is inserted in a tight enclosure filled with pressurized superfluid helium of 0.125 MPa at 1.8 K. The thick casing is cooled to 4.5 K by 1.8 MPa in 4.5 K supercritical helium circulation. Around this thick casing, a 80 K thermal shield protects the parts at very low temperatures from the thermal radiation, which is cooled by pressurized helium at 80 K and 1.8 MPa. A new measurement method for helium mass flow rate of 80 K shield and 4.5 K casing is described in this paper. The commissioning was done on the two helium loops of the cryoplant: the supercritical 4.5 K thick casing and 80 K shields. The purpose is to improve control of the 4.5 K and 80 K refrigeration loops. 展开更多
关键词 mass flow rate VALVE MEASUREMENT HELIUM
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Partial phase flow rate measurements for stratified oil-water flow in horizontal wells
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作者 SONG Hongwei GUO Haimin +1 位作者 GUO Shuai SHI Hangyu 《Petroleum Exploration and Development》 2020年第3期613-622,共10页
To accurately measure and evaluate the oil-water production profile of horizontal wells, a dynamic measurement experiment of oil-water two-phase flow in horizontal wells and numerical simulation were combined to estab... To accurately measure and evaluate the oil-water production profile of horizontal wells, a dynamic measurement experiment of oil-water two-phase flow in horizontal wells and numerical simulation were combined to establish a method for measuring the partial phase flow rate of oil-water two-phase stratified flow in horizontal wells. An experimental work was performed in horizontal oil-water two-phase flow simulation well using combination production logging tool including mini-capacitance sensor and mini-spinner. The combination tool provides a recording of holdup and velocity profiles at five different heights of the borehole cross-section. The effect of total flow rate and water-cut on the response of spinner and capacitive sensor at five measured positions were investigated. The capacitance water holdup interpolation imaging algorithm was used to determine the local fluid property and oil-water interface height, and the measured local fluid speed was combined with the numerical simulation result to establish an optimal calculation model for obtaining the partial phase flow rate of the oil-water two-phase stratified flow in the horizontal well. The calculated flow rates of five measured points are basically consistent with the experimental data, the total flow rate and water holdup from calculation are in agreement with the set values in the experiment too, suggesting that the method has high accuracy. 展开更多
关键词 horizontal well oil-water two-phase flow stratified flow regime flow rate measurement fluid dynamics experiment production logging
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Re-measuring International Short-term Capital Flow into China with Varying Methods
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作者 张明 《China Economist》 2011年第5期80-92,共13页
关键词 资本流动 国际资本 短期 中国 测量 数据综合 金融市场 估计
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Experimental study on preferential solution flow during dump leaching of low-grade ores 被引量:3
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作者 尹升华 吴爱祥 +1 位作者 苏永定 张杰 《Journal of Central South University of Technology》 EI 2007年第4期584-588,共5页
The phenomenon of preferential solution flow during dump leaching of low-grade ores was studied.The formative mechanism of preferential solution flow was investigated through analyzing the relationship between permeab... The phenomenon of preferential solution flow during dump leaching of low-grade ores was studied.The formative mechanism of preferential solution flow was investigated through analyzing the relationship between permeability and ore diameter,and the relationship between surface tension and ore diameter.The preferential solution flow happened within the fine ore area when the dump was unsaturated.And it could happen within the coarse ore area when the dump became saturated.The results of experiment show that the outflow of coarse ore area increases sharply with higher applied rate.The outflow of fine ore area is greater than that of coarse ore area when the applied rate is below 3.2 L/min,and the preferential solution flow happens in fine ore area.But the preferential solution flow happens in coarse ore area when the applied rate is higher than 3.2 L/min.The result of the experiment is consistent with the mechanism analyzing. 展开更多
关键词 低等级矿石 渗透性 表面张力 排土场
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FlowLevelCon油气井动液面连续监测系统的研制及应用 被引量:1
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作者 毛军军 杨若谷 +3 位作者 魏方方 任桂山 苏锋 米立飞 《数码设计》 2017年第6期216-218,共3页
在油田的开发以及采油过程中,动液面是一个非常重要的参数。动液面值的测量对掌握油井生产工况和调整生产参数均十分关键,为及时准确地测量油井液面深度,研制了一套FlowLevelCon油气井动液面连续监测系统;本文介绍了该系统的测量原理、... 在油田的开发以及采油过程中,动液面是一个非常重要的参数。动液面值的测量对掌握油井生产工况和调整生产参数均十分关键,为及时准确地测量油井液面深度,研制了一套FlowLevelCon油气井动液面连续监测系统;本文介绍了该系统的测量原理、软硬件实现过程及现场应用情况。通过该系统在大港油田对不同工况油井的试验效果表明,单井动液面计量误差在1.0%以内,满足油田现场计量需求。 展开更多
关键词 油井动液面 flowLevelCon 回声法 在线计量
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Possibility of a Straightening Flow-Meter by Using Woven Screen
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作者 Takahiro Tsuchiya Yota Koishi +1 位作者 Mitsuo Iwamoto Hidemi Yamada 《Open Journal of Fluid Dynamics》 2015年第1期34-38,共5页
In this paper, the possibility of the flow rate measurement for a circular pipe flow by using a wo-ven screen with the property of straightening un-uniform flows is discussed. The resistance coefficient and the flow r... In this paper, the possibility of the flow rate measurement for a circular pipe flow by using a wo-ven screen with the property of straightening un-uniform flows is discussed. The resistance coefficient and the flow rate coefficient are estimated from the pressure difference caused by the woven screen under the experiment ranges of the wire Reynolds number, Red = 2.2 × 102-1.8 × 103, and of the open area ratio, β = 0.28-0.65. As a result, the resistance coefficient decreases and the flow rate coefficient increases as the wire Reynolds number Red or the open area ratio β increases. In addition, both coefficients are not affected by the difference between uniform and turbulent pipe flows approaching the woven screen. Therefore, the possibility of a flow-meter having the property to straighten the un-uniform flow is expected. 展开更多
关键词 flow rate Measurement Woven SCREEN flow-Straightening Resistance COEFFICIENT
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THE CLINICAL SIGNIFICANCE OF FLOW CYTOMETRIC DEOXYRIBONUCLEIC ACID MEASUREMENT OF DEPARA-FFINIZED SPECIMEN IN BLADDER TUMOR
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作者 王泽 缪廷杰 +1 位作者 熊汝成 曹世龙 《Chinese Journal of Cancer Research》 SCIE CAS CSCD 1991年第1期77-81,共5页
A retrospective study of flow cytometric measurements on paraffin-embedded tumor specimens from 188 patients with bladder tumor was conducted. The results were analyzed in combination with the morphological variation ... A retrospective study of flow cytometric measurements on paraffin-embedded tumor specimens from 188 patients with bladder tumor was conducted. The results were analyzed in combination with the morphological variation of bladder tumors. It was found that the DNA ploid pottern, degree of infiltration and the multiplicity of bladder tumor were closely related with tumor recurrence, among which the DNA ploid pattern was most significant. In aneuploid bladder tumors the recurrent rate and mean annual recurrence frequency were 76.7% and 1.46, and those in the diploid bladder tumors were 18.7% and 0.33 respectively. Aneuploid was the most indicative parameter of the recurrence in bladder tumors. In addition, according to the DNA ploid pattern and DNA index (DI), the aneuploid tumors in our group were divided into 4 types, namely, tetraploid tumors, npn-euploid with DI(?)1.5, non-euploid tumors with DI>1.5 and two-aneuploid tumors. The results showed that the recurrent rate of tetraploid tumors was relatively lower and it became higher and higher in the following order: non-euploid tumors with DI(?)1.5, non-euploid tumors with DI>1.5, and two-aneuploid tumors. This indicates that there are different biological behaviors in tumors with different ploid pattern. Finally, the correlation between DNA ploid pattern and tumor metastasis was also discussed. 展开更多
关键词 rate THE CLINICAL SIGNIFICANCE OF flow CYTOMETRIC DEOXYRIBONUCLEIC ACID MEASUREMENT OF DEPARA-FFINIZED SPECIMEN IN BLADDER TUMOR DNA FCM
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Experiment on Vaporization of Jet into Cross-Flow
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作者 MA Cuuxiang DENG Yucnhao +1 位作者 YAN Yingwen XU Huasheng 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2019年第6期977-985,共9页
The injection characteristics of the main fuel nozzle,which is widely applied in advanced lean-premixed-prevaporized(LPP)low-emission combustors,can be simplified as the atomization and vaporization processes of a jet... The injection characteristics of the main fuel nozzle,which is widely applied in advanced lean-premixed-prevaporized(LPP)low-emission combustors,can be simplified as the atomization and vaporization processes of a jet into cross-flow.In this study,a nozzle with a diameter of 0.4 mm is designed and processed through the heating of the inlet air,and the vaporization characteristics are investigated.The optical measurement and cyclone separation methods are separately used to investigate the evaporation rate of a jet into cross-flow.Experimental results show that the fuel evaporation rate in cross-flow is mainly affected by the Weber number(We),equivalent ratio(φ),momentum rate of fuel to air(q),and air temperature.In addition,the inlet temperature is a crucial factor for the evaporation ratio of a jet into cross-flow.The evaporation results measured by two different methods in the same cross-flow are very close to each other with a deviation within 10%. 展开更多
关键词 evaporation rate JET CROSS-flow optical measurement cyclone separation method
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进液量对气举式同向出流旋流器分离特性影响
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作者 刘彩玉 郑九洲 +1 位作者 李枫 张勇 《机械设计与制造》 北大核心 2024年第2期165-169,共5页
为了提高旋流器的分离效率,提出一种气举式同向出流水力旋流器结构,通过注气的方式将旋流器轴心的油核举升至溢流口,加速油核向溢流口方向运动,进而提升旋流器的分离性能。基于雷诺应力模型(Reynolds Stress Model,RSM)与多相流模型(Mix... 为了提高旋流器的分离效率,提出一种气举式同向出流水力旋流器结构,通过注气的方式将旋流器轴心的油核举升至溢流口,加速油核向溢流口方向运动,进而提升旋流器的分离性能。基于雷诺应力模型(Reynolds Stress Model,RSM)与多相流模型(Mixture),模拟计算了入口进液量对气举式同向出流旋流器分离性能的影响,分析了进液量对旋流器内气核形态、速度场分布以及分离性能的影响规律。数值模拟结果表明:进液量分布在(3.6~8.4)m^(3)/h范围内时,随着进液量的增加,注气口处压力逐渐增大,混合液内各相介质的轴向速度与径向速度均有显著提高,旋流器轴心处的油相体积分数明显增大,旋流器的分离效率从64%增至77.9%。 展开更多
关键词 进液量 旋流器 同向出流 数值模拟 分离效率
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基于居里面深度对中国东北部大地热流的研究
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作者 邱楠生 许晴 +2 位作者 朱传庆 宋佳霖 李潇 《地质学报》 EI CAS CSCD 北大核心 2024年第3期680-691,共12页
大地热流值是表征地球热状态的重要参数,也是进行深部地温预测和评价一个地区地热资源的最基本数据。受钻孔测温的影响,盆地外的无钻孔测温地区缺少实测的大地热流值。目前的热流分布图都是依据相邻盆地的实测值进行插值绘制的,无钻孔... 大地热流值是表征地球热状态的重要参数,也是进行深部地温预测和评价一个地区地热资源的最基本数据。受钻孔测温的影响,盆地外的无钻孔测温地区缺少实测的大地热流值。目前的热流分布图都是依据相邻盆地的实测值进行插值绘制的,无钻孔区热流值可信度较低。由于岩石居里点与温度密切相关,可以通过居里面深度来研究地表热流值。本文依据东北地区现有的居里面深度分布图,结合实测的岩石热导率、岩石生热率数据和相应的地壳分层状况,计算了东北地区的大地热流值,重新绘制了中国东北地区精细的大地热流分布图。东北地区整体大地热流处于42.5~95 mW/m~2之间,热流高值位于五大连池及敦化-密山断裂带海龙—牡丹江一带,松辽盆地内部、小兴安岭和长春-延吉缝合带也有局部的高热流值。热流高值与居里面隆起区域有较高的一致性,即居里面隆起处热流较高,而坳陷区热流较低。本次研究填补了中国东部地区热流实测值空白,为该区深部地温预测和地热资源评价提供了更加准确的参数。 展开更多
关键词 居里面 大地热流 岩石热导率 岩石生热率 地热资源
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地热储层岩体粗糙裂隙的热流耦合效应研究
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作者 刘先珊 李宇 +1 位作者 李满 杨欣 《哈尔滨工程大学学报》 EI CAS CSCD 北大核心 2024年第5期852-862,共11页
为了解决地热开采涉及复杂的多物理场耦合问题,提高开采效率,本文针对开采过程中的渗流-传热问题以离散元软件3DEC构建岩体粗糙裂隙热-流耦合数值模型。考虑不同三维形貌特征的岩体裂隙,模拟水力开度为19.17μm在不同流速时的水-岩温度... 为了解决地热开采涉及复杂的多物理场耦合问题,提高开采效率,本文针对开采过程中的渗流-传热问题以离散元软件3DEC构建岩体粗糙裂隙热-流耦合数值模型。考虑不同三维形貌特征的岩体裂隙,模拟水力开度为19.17μm在不同流速时的水-岩温度变化规律。结果表明:由于裂隙形貌的阻滞作用,粗糙面出水口温度下降较慢,出水口温度有所上升,模型达到稳态所需的时间随流速和对流换热系数的增大而减小。裂隙形貌对流体和岩体温度分布均有影响,粗糙裂隙面的冷锋形态和裂隙面的形貌密切相关。光滑裂隙热突破快于粗糙裂隙,增加裂隙面的粗糙度有助于延长热突破时间。粗糙裂隙面相对于光滑裂隙面的总热量提取率略有提升,流速和对流换热系数的增加显著提高总热量提取率。通过本文研究可以为地热能系统的设计提供重要参数和指导,能够提高地热能开发利用效率。 展开更多
关键词 干热岩 渗流-传热 三维形貌 水力开度 流速 对流换热系数 粗糙裂隙面 热采率 热突破
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基于COMSOL的剪切速率对超声波流量测量影响分析
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作者 刘升虎 魏一 王建志 《石油化工应用》 CAS 2024年第2期33-37,共5页
为了分析影响超声波流量测量结果的因素,提高超声波流量测量的准确性,需要研究聚合物溶液剪切速率对于流体流态和超声波流量计接收声压的影响,利用多物理场有限元软件COMSOL建立超声波流量计三维模型进行仿真,通过流体域的背景流速曲线... 为了分析影响超声波流量测量结果的因素,提高超声波流量测量的准确性,需要研究聚合物溶液剪切速率对于流体流态和超声波流量计接收声压的影响,利用多物理场有限元软件COMSOL建立超声波流量计三维模型进行仿真,通过流体域的背景流速曲线和超声波接收器波形图来分析剪切速率的影响。结果表明,在其他条件不变的情况下,随着剪切速率的增大流体流态趋向于湍流,超声波流量计接收器声压最大值与最小值相差1%,其对超声波流量计测量结果影响较小可忽略。 展开更多
关键词 聚合物 超声波 剪切速率 流量测量 COMSOL
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Improvements to machining surface quality by controlling the flow direction of electrolyte during electrochemical sinking and milling of titanium alloy 被引量:3
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作者 LIU Yang QU NingSong 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2020年第12期2698-2708,共11页
Electrochemical milling is eminently suitable for machining aerospace parts(which usually have complex structures) because of its great flexibility. However,titanium alloys are particularly sensitive to changes in the... Electrochemical milling is eminently suitable for machining aerospace parts(which usually have complex structures) because of its great flexibility. However,titanium alloys are particularly sensitive to changes in the flow field,which often cause severe pitting corrosion of the machined surface. Although electrochemical sinking and milling(ESM) can restrict the flow of electrolyte and reduce pitting corrosion,the quality of the machined surface is not ideal because the latter are susceptible to stray corrosion. To reduce such corrosion and improve the surface quality,the internal flow channel of the tool electrode and the cutting depth were investigated thoroughly. Extensive experiments revealed that stray corrosion could be reduced significantly and surface quality improved by controlling the electrolyte flow direction in the machining area,which was achieved by changing the style of the internal flow channel of the tool electrode. These reductions in corrosion and surface roughness were achieved using a tool electrode with a triangular internal flow channel. In addition,the main components and micro-hardness of the machined surface were close to that of the TB6 titanium alloy substrate,which helped to maintain the inherent high strength of the titanium alloy. The surface of the workpiece changed from being hydrophilic to being hydrophobic,which reduced the flow resistance. 展开更多
关键词 electrochemical sinking and milling titanium alloys flow direction surface quality and characteristics
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大口径管道烟气流量测量方法综述
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作者 谢子立 卢志民 +5 位作者 姚顺春 刘泽明 黄泳如 莫爵徽 叶建威 林玥 《热力发电》 CAS CSCD 北大核心 2024年第4期112-124,共13页
2021年全国碳市场开启,为了提高碳交易的准确性,需要做到碳排放数据的可测量、可报告、可核查。在这种背景下,烟气在线监测系统作为一种碳排放量化方法得到了重视。其有效工作的基础是烟气流量的准确测量。但电厂烟囱尺寸大,内部烟气流... 2021年全国碳市场开启,为了提高碳交易的准确性,需要做到碳排放数据的可测量、可报告、可核查。在这种背景下,烟气在线监测系统作为一种碳排放量化方法得到了重视。其有效工作的基础是烟气流量的准确测量。但电厂烟囱尺寸大,内部烟气流动特性复杂,烟气流量难以准确测量。重点分析了皮托管流量计和气体超声波流量计在大口径管道流量测量中的研究现状,详细介绍了大口径管道气体流量测量技术。此外,还介绍了一种独立的流量测量方法—示踪气体稀释法,探讨其发展现状及作为一种流量标定方法的潜力。 展开更多
关键词 大口径管道 流量测量 烟气流场 示踪气体稀释法
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基于动态平衡布局的输电网潮流图自动生成方法
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作者 苏运光 陈连杰 +3 位作者 高源 司鹏 黄昆 许花 《电力系统自动化》 EI CSCD 北大核心 2024年第15期169-175,共7页
为解决输电网潮流图自动生成中厂站布局与线路布线问题,提出基于动态平衡布局的输电网潮流图自动生成方法。针对厂站布局,首先,在力导向算法的基础上引入基于图纸中心点的惩罚函数,以解决力导向算法布局不均匀的问题,提高布局的均布度;... 为解决输电网潮流图自动生成中厂站布局与线路布线问题,提出基于动态平衡布局的输电网潮流图自动生成方法。针对厂站布局,首先,在力导向算法的基础上引入基于图纸中心点的惩罚函数,以解决力导向算法布局不均匀的问题,提高布局的均布度;然后,利用厂站分布率参数控制算法平衡次数,引导厂站向图纸边界运动,解决布局自动适应给定图幅大小的问题;最后,通过位置映射变换将围绕图纸中心点的椭圆分布转换为矩形分布,解决引入惩罚函数布局均匀但不符合传统输电网潮流图绘制习惯的问题。针对线路布线提出以构建通道树为中心的布线方法,有效降低布线交点个数,提升布线效果。所提布局与布线算法在实际工程应用中取得了良好的效果,通过案例验证了输电网潮流图自动生成的正确性和有效性。 展开更多
关键词 输电网 潮流 自动生成 厂站布局 线路布线 力导向算法 均布度 分布率 通道树
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深部煤系储层缝间干扰多裂缝同步扩展规律试验研究
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作者 陈志杰 王开 +4 位作者 张小强 姜玉龙 丁一 侯建 王文伟 《矿业安全与环保》 CAS 北大核心 2024年第2期74-81,89,共9页
为研究深部煤系储层缝间干扰多裂缝同步扩展规律,采用自行研制的TCHFSM-I型大尺寸真三轴压裂渗流模拟装置,开展不同压裂孔间距、不同注液速率对多裂缝同步扩展规律的影响试验。通过观察和分析压裂过程中裂缝扩展形态、注液压力演化规律... 为研究深部煤系储层缝间干扰多裂缝同步扩展规律,采用自行研制的TCHFSM-I型大尺寸真三轴压裂渗流模拟装置,开展不同压裂孔间距、不同注液速率对多裂缝同步扩展规律的影响试验。通过观察和分析压裂过程中裂缝扩展形态、注液压力演化规律,以及声发射动态响应特征和注液流量演化特征,结果表明:压裂孔间距较小时,左右两侧裂缝扩展长度大于中部裂缝,随着压裂孔间距增大,左中右3条裂缝均衡扩展;增大注液速率可以使起裂压力增高,多裂缝长度增加,有效提高储层改造体积;增大压裂孔间距和注液速率,可以使左中右3个压裂孔的注液流量占比更均衡。 展开更多
关键词 深部煤系 多孔水力压裂 缝间应力干扰 压裂孔间距 注液速率 声发射特征 流量演化规律
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基于恒定功率的热式流量计设计与测试
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作者 罗莉 冯全源 +1 位作者 何璇 刘彬 《仪表技术与传感器》 CSCD 北大核心 2024年第1期41-45,75,共6页
针对热式流量计的温度漂移问题,提出了一种恒定功率模式下的热式流量计结构,并对其数字校准方法进行了研究。与传统热式流量计相比,增加了环境探头,该探头内嵌于流体管道壁。各传感器之间采用隔热措施,利用环境探头和感温探头测量得到... 针对热式流量计的温度漂移问题,提出了一种恒定功率模式下的热式流量计结构,并对其数字校准方法进行了研究。与传统热式流量计相比,增加了环境探头,该探头内嵌于流体管道壁。各传感器之间采用隔热措施,利用环境探头和感温探头测量得到的电压信号进行实时数字校准。采用音速喷嘴法燃气表检验装置对流量计进行检测。检测结果显示:流量在0.016~0.25 m^(3)/h范围内误差率小于0.5%,流量在0.25~6 m^(3)/h范围内误差率小于1.0%,温度漂移现象有效改善。 展开更多
关键词 热式流量计 恒定功率 温度漂移 数字校准方法 流量检测 误差率
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局部土地利用类型变化对城市水文过程的影响研究
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作者 李欣怡 侯精明 +4 位作者 潘占鹏 景静 王添 周庆诗 董欣刚 《人民黄河》 CAS 北大核心 2024年第6期26-33,共8页
为探究城市下垫面局部土地利用类型变化对城市水文过程的影响,采用高效高精度城市雨洪模型(GAST)耦合管网模型(SWMM),模拟不同降雨重现期下动态改变土地利用类型(单块无下渗土地C_(1)、多块组合无下渗土地C_(2)、单块裸土地C_(3)、单块... 为探究城市下垫面局部土地利用类型变化对城市水文过程的影响,采用高效高精度城市雨洪模型(GAST)耦合管网模型(SWMM),模拟不同降雨重现期下动态改变土地利用类型(单块无下渗土地C_(1)、多块组合无下渗土地C_(2)、单块裸土地C_(3)、单块草地C_(4)和单块林地C_(5))对城市地表积水、管网排水的影响。结果表明:改变局部原始土地利用类型(B1)在小降雨重现期下降低了城市积水量,而在大降雨重现期下改变土地下渗面积和区域位置无法进一步减少积水,此时则需考虑非工程措施的极端暴雨应对模式。不同动态规划区域下渗强度导致管网排口流量增幅不同(C_(2)>C_(1)>C_(3)>C_(4)>C_(5)),隔渗能力越强对管网排口流量增幅影响越大,而管网径流控制率则呈相反趋势。结合对积水量的影响可知,增加下垫面下渗能力并结合排水系统可进一步降低城市内涝风险和管网排水负荷,且管网径流控制率同样可以作为评估动态规划可行性的一个重要指标。 展开更多
关键词 耦合模型 动态规划 地表积涝 管网流量 径流控制率
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