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极高环境温度下的两级空调系统研究 被引量:3
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作者 顾兆林 郑东宏 +1 位作者 李云 徐冬平 《西安交通大学学报》 EI CAS CSCD 北大核心 2002年第7期757-760,共4页
针对极高环境温度下单级空调制冷系统运行中存在着的诸如压缩机的压缩比大、换热器热负荷大、性能系数小以及经济性差等问题 ,采用一级节流中间不完全冷却和一级节流中间完全冷却的两级制冷系统对单级制冷系统进行改进 ,使压缩机排气温... 针对极高环境温度下单级空调制冷系统运行中存在着的诸如压缩机的压缩比大、换热器热负荷大、性能系数小以及经济性差等问题 ,采用一级节流中间不完全冷却和一级节流中间完全冷却的两级制冷系统对单级制冷系统进行改进 ,使压缩机排气温度降低了 10℃ (一级节流中间不完全冷却 )或 2 0℃ (一级节流中间完全冷却 ) ,符合排气温度的要求 ,同时性能系数提高了 15 % ,因而使压缩机功耗降低 ,达到了提高单位工质的制冷量并使性能系数最优的目标 . 展开更多
关键词 高环境温度 两级空调系统 性能系数 两级压缩 制冷循环 压缩机 两级制冷系统
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高环境温度下冰箱运行可靠性分析 被引量:1
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作者 吴峰 杨洪涛 廖自敏 《日用电器》 2021年第8期86-91,97,共7页
冰箱在环境温度较高的条件下运行,由于冰箱运行负荷大,通电后可能出现压缩机保护机制启动而跳机,导致冰箱制冷效果差。另外冰箱高环境温度下运行,冰箱表面一些用户能接触到的地方温度可能偏高,存在烫伤人的风险。这些冰箱在高环境温度... 冰箱在环境温度较高的条件下运行,由于冰箱运行负荷大,通电后可能出现压缩机保护机制启动而跳机,导致冰箱制冷效果差。另外冰箱高环境温度下运行,冰箱表面一些用户能接触到的地方温度可能偏高,存在烫伤人的风险。这些冰箱在高环境温度下运行的可靠性问题将会造成极差用户体验,本文将以实际工作中案例来介绍如何解决高环境温度下冰箱运行存在一些可靠性的问题,提高产品用户体验。 展开更多
关键词 高环境温度 制冷效果 表面温度
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环境温度变化下低压隔离开关的降容试验
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作者 龚节维 王兆宇 +1 位作者 岳宝强 陈红群 《机电工程技术》 2023年第9期225-229,共5页
低压隔离开关是一种在断开状态下能符合规定的隔离功能要求的一种机械开关电器,在正常使用中应严格按照其各项额定值选择适合的开关,其中额定工作电流是十分重要的选择项。低压隔离开关(以下称“开关”)额定工作电流的确定与开关使用环... 低压隔离开关是一种在断开状态下能符合规定的隔离功能要求的一种机械开关电器,在正常使用中应严格按照其各项额定值选择适合的开关,其中额定工作电流是十分重要的选择项。低压隔离开关(以下称“开关”)额定工作电流的确定与开关使用环境温度以及开关自身温升密切相关。研究不同使用环境温度,特别是在较高温度环境对开关的性能影响。制定了在不同环境温度下的开关温升试验方案并分析其可行性,然后试验得出不同环境下开关的温升数据。进而根据温升的限值要求对开关在不同的环境温度下的额定工作电流的适应性变化进行确认。对开关在较高环境温度下使用时,确定其降容使用的额定工作电流,以使开关性能不受高于标准中规定的环境温度的影响。 展开更多
关键词 低压隔离开关 温升 额定工作电流 高环境温度
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高温度环境下大功率PCB板的设计 被引量:6
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作者 胡松涛 付娟 +1 位作者 王振收 李旺 《机械与电子》 2015年第5期33-35,共3页
多层PCB在电子插件和设备中使用广泛。随着电子产品的轻薄小型化、高性能化,导致电路板级散热问题愈发严重,在高温度环境下,按以往粗放型设计方式无法满足设计要求。主要探讨了大功率印制板的设计方法,提出了一种新型的多层印制电路板(P... 多层PCB在电子插件和设备中使用广泛。随着电子产品的轻薄小型化、高性能化,导致电路板级散热问题愈发严重,在高温度环境下,按以往粗放型设计方式无法满足设计要求。主要探讨了大功率印制板的设计方法,提出了一种新型的多层印制电路板(PCB)热设计方法。根据印制板上器件的功耗进行理论计算和仿真分析,有效降低印制电路板级温度,具有较好的实用性,使得元器件降额设计达到要求。 展开更多
关键词 印制板 热设计 热传导 温度环境
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双效一体式谷物冷却机的应用
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作者 温素珍 袁杰 +2 位作者 金阿龙 麻林海 刘斌斌 《中国科技期刊数据库 工业A》 2024年第3期0029-0032,共4页
随着环保和资源节约的重要性不断上升,谷物冷却机作为农业和工业生产中重要的设备,也需要不断创新以适应不同环境条件下的需求。双效一体式谷物冷却机是一种创新型的冷却设备,具有在不同环境温度下工作的灵活性,可显著提高节约用水用电... 随着环保和资源节约的重要性不断上升,谷物冷却机作为农业和工业生产中重要的设备,也需要不断创新以适应不同环境条件下的需求。双效一体式谷物冷却机是一种创新型的冷却设备,具有在不同环境温度下工作的灵活性,可显著提高节约用水用电的效果。本文将探讨该冷却机的工作原理以及其在实际应用中的效果,重点关注其在低环境温度和高环境温度条件下的工作模式切换和冷凝水回收利用。 展开更多
关键词 双效一体式谷物冷却机 环境温度 高环境温度 节约用水用电
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不同温度下的乙烯-三氟氯乙烯共聚物薄膜单轴拉伸试验
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作者 刘昶江 赵兵 陈务军 《上海交通大学学报》 EI CAS CSCD 北大核心 2021年第4期387-393,共7页
对厚度为250μm的乙烯-三氟氯乙烯共聚物(ECTFE)薄膜进行了单轴拉伸试验,考虑了不同的低-高温度(分别为-50、-40、-30、-20、-10、0、10、20、30、40、50、60、70及80℃)效应,试件截取方向为机器方向.得到了ECTFE薄膜在不同温度下的拉... 对厚度为250μm的乙烯-三氟氯乙烯共聚物(ECTFE)薄膜进行了单轴拉伸试验,考虑了不同的低-高温度(分别为-50、-40、-30、-20、-10、0、10、20、30、40、50、60、70及80℃)效应,试件截取方向为机器方向.得到了ECTFE薄膜在不同温度下的拉伸应力-应变曲线,通过分析得到了弹性模量、屈服强度、屈服应变、冷拉应力、抗拉强度、断裂延伸率等力学参数及其随温度的变化规律.结果表明:随着温度的降低,应力-应变曲线整体向上抬升,屈服强度、拉伸强度、冷拉应力和弹性模量均增大,断裂延伸率和韧性均减小.在不同温度(-50~80℃)下,弹性模量的差值可达到93%,屈服强度的差值可达到89%,温度变化对ECTFE薄膜力学性能的影响显著.得出了主要力学参数和温度变化的拟合公式,可用于判断ECTFE薄膜在不同温度下的力学性能. 展开更多
关键词 乙烯-三氟氯乙烯共聚物薄膜 低-温度环境 单轴拉伸试验 弹性模量 屈服强度
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带淋水系统的空气源冷热水模块机组制冷性能实验研究 被引量:1
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作者 戴源德 古宗敏 《暖通空调》 北大核心 2013年第8期99-102,共4页
在高环境温度工况下,空气源冷热水模块机组的制冷性能和运行可靠性随着温度升高而降低。为提高机组制冷性能和运行可靠性,研制了带淋水系统的空气源冷热水模块机组样机,并进行了测试实验。实验结果表明,当室外环境温度控制在35~43℃时... 在高环境温度工况下,空气源冷热水模块机组的制冷性能和运行可靠性随着温度升高而降低。为提高机组制冷性能和运行可靠性,研制了带淋水系统的空气源冷热水模块机组样机,并进行了测试实验。实验结果表明,当室外环境温度控制在35~43℃时,开启淋水系统后机组制冷量最大提升31%,性能系数最大提升达63%,排气压力最大降低20%。 展开更多
关键词 空气源冷热水机组 模块机组 淋水系统 制冷性能 高环境温度
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Study on High-Temperature Spectra of Asymptotic Asymmetric-Top Molecule O_3 被引量:1
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作者 SONG Xiao-Shu GUO Yun-Dong +3 位作者 LING-HU Rong-Feng Lv Bing CHENG Xin-Lu YANG Xiang-Dong 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第8期481-485,共5页
The line intensities of 001-000 transition of the asymptotic asymmetric-top Oa molecule at several temperatures are calculated by directly calculating the partition functions and regarding the rotationless transition ... The line intensities of 001-000 transition of the asymptotic asymmetric-top Oa molecule at several temperatures are calculated by directly calculating the partition functions and regarding the rotationless transition dipole moment squared as a constant. The calculated values of the total internM partition sums (TIPS) are consistent with the data of HITRAN database with -0.61% at 296 K. The calculated line intensity data at 500 K and 3000 K are also in excellent agreement with the data in HITRAN database with less than 0.659% and 5.458% at 500 K and 3000 K, which provide a strong support for the calculations of partition function and fine intensity at high temperature. Then we extend the calculation to higher temperatures. The line intensities and simulated spectra of v3 band of the asymptotic asymmetric-top O3 molecule at 4000 and 5000 K are reported. The results are of significance for the studying of the molecular high-temperature spectrum including experimental measurements and theoretical calculations. 展开更多
关键词 asymptotic asymmetric-top molecule line intensities partition functions high temperature spectrum
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A relationship between temperature and aggression in NFL football penalties 被引量:1
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作者 Curtis Craig Randy W.Overbeek +1 位作者 Miles V.Condon Shannon B.Rinaldo 《Journal of Sport and Health Science》 SCIE 2016年第2期205-210,共6页
Background: Increased ambient temperature has been implicated in increased physical aggression, which has important practical consequences. The present study investigates this established relationship between aggress... Background: Increased ambient temperature has been implicated in increased physical aggression, which has important practical consequences. The present study investigates this established relationship between aggressive behavior and ambient temperature in the highly aggressive context of professional football in the National Football League (NFL). Methods: Using a publicly available dataset, authors conducted multiple hierarchical regression analyses on game-level data (2326 games). Results: The analysis revealed that temperature positively predicted aggressive penalties in football, and that this relationship was significant for teams playing at home but not for visiting teams. Conclusion: These results indicate that even in the aggressive context of football, warmer weather contributes to increased violence. Further, the presence of the heat-aggression relationship for the home team suggests that the characteristics of interacting groups may influence whether heat would have an adverse effect on the outcome of those interactions. 展开更多
关键词 AGGRESSION American football INTERGROUP Sports TEMPERATURE
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地下式厂房通风系统设计优化和改造 被引量:1
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作者 陈小捷 田小兵 《陕西水利》 2021年第2期181-183,186,共4页
构皮滩水电站投产初期,副厂房通风系统设计不合理,通风对流不畅,环境温度过高,为杜绝温度过高带来的安全隐患,特将暖通系统进行改造:对原有通风系统进行优化改造,调整通风环境和风路,增设冷水机组为整体风环境进行降温处理。改造后试运... 构皮滩水电站投产初期,副厂房通风系统设计不合理,通风对流不畅,环境温度过高,为杜绝温度过高带来的安全隐患,特将暖通系统进行改造:对原有通风系统进行优化改造,调整通风环境和风路,增设冷水机组为整体风环境进行降温处理。改造后试运行半年时间,暖通系统正常运行稳定,未发现设备缺陷,副厂房环境温度对比改造前有明显改善。 展开更多
关键词 地下厂房 环境温度 通风系统 优化改造
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^(27)Al MAS-NMR study of inorganic polymer formation at ambient temperature
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作者 Sang-Wook AHN Hee-Soo LEE +2 位作者 Wan-Hee YANG Jung-Woo LEE Young-Keun JEONG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第A01期182-187,共6页
Inorganic polymers are a novel class of materials formed by the polymerization of silicon, aluminium and oxygen species to form an amorphous three-dimensional framework structure. The basis of this process is the alka... Inorganic polymers are a novel class of materials formed by the polymerization of silicon, aluminium and oxygen species to form an amorphous three-dimensional framework structure. The basis of this process is the alkaline solutions to induce a certain amount of Si and AI atoms to dissolve from a feedstock such as aluminosilicate. A study of 27A1 MAS-NMR was carried out in an attempt to understand the reaction mechanism of the inorganic polymerization at ambient temperature. Scanning electron microscopy (SEM) and X-ray diflYactometry (XRD) were also employed to establish the composition and microstructure of the inorganic polymerization. Specimens were prepared with different A1/Si mole ratios from the starting materials. The higher the AI content, the more sufficient the AI atoms that can combine with SiO4, and the longer the reaction time, the more the bonded Si--O--A1--O polymer structure, and then the higher the A1 content, the fewer the octahedral A1 with a uniform Si--O--A1--O structure in four directions, because four AI atoms are combined with SiO4, resulting in a uniform Si--O--AI--O structure in four directions. The results show that they have an amorphous microstructure. 展开更多
关键词 inorganic polymer AMORPHOUS TETRAHEDRAL
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Entropy Analyses of Droplet Combustion in Convective Environment with Small Reynolds Number 被引量:1
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作者 ZHANG Xiaobin ZHANGWei ZHANG Xuejun 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2013年第6期654-662,共9页
This paper analyzes the entropy generation rate of simple pure droplet combustion in a tempera-ture-elevated air convective environment based on the solutions of flow, and heat and mass transfer between the two phases... This paper analyzes the entropy generation rate of simple pure droplet combustion in a tempera-ture-elevated air convective environment based on the solutions of flow, and heat and mass transfer between the two phases. The flow-field calculations are carried out by solving the respective conservation equations for each phase, accounting for the droplet deformation with the axisymmetric model. The effects of the temperature, velocity and oxygen fraction of the free stream air on the total entropy generation rate in the process of the droplet combustion are investigated. Special attention is given to analyze the quantitative effects of droplet deformation. The results re-veal that the entropy generation rate due to chemical reaction occupies a large fraction of the total entropy generated, as a result of the large areas covered by the flame. Although, the magnitude of the entropy generation rate per volume due to heat transfer and combined mass and heat transfer has a magnitude of one order greater than that due to chemical reaction, they cover a very limited area, leading to a small fraction of the total entropy generated. The en-tropy generation rate due to mass transfer is negligible. High temperature and high velocity of the free stream are advantageous to increase the exergy efficiency in the range of small Reynolds number (<1) from the viewpoint of the second-law analysis over the droplet lifetime. The effect of droplet deformation on the total entropy generation is the modest. 展开更多
关键词 entropy generation exergy analysis droplet combustion numerical simulation
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Research on Wireless Sensor Network in Aquaculture
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作者 Jun Zhao 《International Journal of Technology Management》 2014年第7期18-20,共3页
The paper design intelligent monitoring system of aquaculture based on CC2530 wireless sensor networks, combined with the actual situation, takes the tilapia as an example to analyze detailed of the process in intelli... The paper design intelligent monitoring system of aquaculture based on CC2530 wireless sensor networks, combined with the actual situation, takes the tilapia as an example to analyze detailed of the process in intelligent high density culture. At the same time, the paper introduced each function module of aquaculture for the intelligent monitoring system and formulate control standard according to the aquatic products in different growth stages of demand, through the real-time monitoring of aquaculture environment, measured the standard parameter setting of parameters and the system automatically adjusts the aquaculture environment comparison. The test results show that the temperature error is in the range of 0.5 ℃, dissolved oxygen amount of error is in the range of 0.3mg/L, the error of pH value is within 0.3, system data transmission correct rate is more than 98%. 展开更多
关键词 RFID IOT WSN MONITORING AQUACULTURE
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Improving the thermal shock resistance of ceramics by crack arrest blocks
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作者 WANG Yan Wei XIA Biao +2 位作者 SU Hong Hong CHEN Hang FENG Xue 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2016年第6期913-919,共7页
Ceramics used in the high temperature environment are inevitably subjected to sudden temperature change, which may lead to catastrophic thermal shock failure due to the intrinsic brittleness of ceramics. In this paper... Ceramics used in the high temperature environment are inevitably subjected to sudden temperature change, which may lead to catastrophic thermal shock failure due to the intrinsic brittleness of ceramics. In this paper, an experimental platform is designed to realize the in-situ observation during the thermal shock experiments. Experimental results show that all the cracks initiate from one of the edge midpoints and propagate to another one for square specimens. Such experimental observation is consistent with the maximum tensile stress zone with the maximum temperature gradient given by the finite element method(FEM). The different crack modes resulting from different heating rates after thermal shock experiments are observed and analyzed. Comparison between different clamping methods is conducted to study the effects of boundary conditions on the thermal shock experiments. Furthermore, in order to improve the thermal shock performance of alumina ceramics, crack arrest blocks are added near the edge midpoint. The thickness, shape and arrangement of the blocks are systematically investigated to understand the mechanism of improvement of thermal shock resistance. 展开更多
关键词 thermal shock ultra-high temperature ceramics crack arrest blocks in-situ dynamic observation
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