共查询到19条相似文献,搜索用时 140 毫秒
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不可或缺的原材料上世纪80年代起,塑料和家电作为新兴轻工行业在中国得到蓬勃发展。随着家电产业的发展,塑料应用于家电产品越来越多, 从事家电产品配套的塑料企业很多都具有相当的实力,产能上万吨级的企业也为数不少。目前,家电及其他电子电器产品主要选用五大基础树脂(如ABS、PS、PP等),PI泡沫塑料和各种工程塑料 (如PA、POM、PTFE等)以及性能优良、阻燃性能好且安全环保的改性工程塑料。 相似文献
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《中国电机工程学报》2016,(16)
机动车排放颗粒物是我国城市大气PM_(2.5)重要来源。缸内直喷(gasoline direct injection,GDI)汽油机具有油耗低、CO2排放低等优点,将成为未来汽油车发展方向。然而GDI汽油机颗粒物排放高,造成的环境影响值得关注。有机物(organic matters,OM)是大气颗粒物的重要组分,有着重要的健康效应和气候效应。其中可以定量检测的部分颗粒有机物(particulate organic matters,POM)有着较好的源指示作用。通过台架实验研究了GDI汽油机排放PM_(2.5)中POM的组成、排放因子等的特征,以及转速、负荷、催化剂等因素对POM组成的影响,给出汽油机排放POM源谱。定量颗粒有机物的总质量分别可以占到总有机物OM和PM_(2.5)质量浓度的14%~56%和7%~44%。多环芳烃、正构烷烃、正构烷酸、芳香酸、二元羧酸是最主要的物种。POM排放因子随转速增加而增大,对于中、低转速,POM排放因子随着负荷的增加呈现出先降低后增加的趋势;在高转速时,POM排放因子随着负荷增加而增加。三效催化剂对颗粒有机物的排放的削减作用可达到19%~64%。我国汽油车排放POM源谱与国外源谱有差异。采集和测量我国实地源样品,得到符合我国实际情况的汽油车POM源谱,对于解析我国大气颗粒物来源中的汽油车贡献至关重要。 相似文献
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基于POM模式的感潮河段三维水动力模拟 总被引:3,自引:0,他引:3
随着工程要求的不断提高,感潮河段三维水动力的正确模拟有着十分重要的意义.同时,美国普林斯顿大学开发的海洋模型POM已经逐渐应用于我国海湾潮汐流的数值模拟中,并得到了进一步的修正和完善.本文基于POM模式,利用明渠垂向流速分布的经验公式分析了三种紊动黏性系数计算方法对流速的影响;结合前人对POM模式的修正工作,建立了感潮河段的三维水动力模型;将该模型应用到长江下游太仓段的计算中,结果表明,基于POM模式建立的感潮河段三维水动力模型的计算值与实测值拟合较好,能够充分反映感潮河段水位以及水流流速随时间的变化情况. 相似文献
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POM、LCP、 FRP是三种高模量、低线膨胀系数光纤的二次被覆材料。文中介绍了此三种材料的结构及工艺并作了比较,认为 LCP不仅具有高强度、高模量和机械特性优良的特点,而且具有优良的成型加工性能,并能用普通挤出机挤出,以实现光纤快速被覆。 相似文献
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一种新的触头装置,主要是基于光伏系统中所用的旋转隔离开关。由于该旋转隔离开关应用于直流电源,因而在开关接通闭合时,对触头的各项参数性能要求比较高,其性能直接关系到隔离开关的电气性能和使用寿命。本文对隔离开关产品的触头装置的特点和结构进行了阐述,然后对本产品的直流灭弧的伏安特性进行了分析,并对触头装置整体性能进行测试,以验证产品是否满足规定的性能要求。 相似文献
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新型耐热阻燃和耐热环氧玻璃布板国内外水平对比 总被引:1,自引:0,他引:1
本文介绍了国内外新型耐热阻燃和耐热环氧玻璃布板在性能、工艺路线和原材料方面的对比结果,表明部分国产产品的性能已达到国外同类产品的水平,国内源材料的性能是影响该类环氧玻璃布板性能的主要因素。 相似文献
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The effects of absorbed water on the gamma-relaxation process of polyoxymethylene (POM) were studied using dielectric spectroscopy and thermogravimetric analysis. The spectra were measured isothermally over the frequency range of 10 MHz to 2 GHz, and the water content was varied from dried to 1.65 wt% (saturated). The strength and rate of the gamma-relaxation process increased with increasing water content, contradicting earlier studies that found this process to be relatively insensitive to changes in the molecular environment. Two different formalisms that express the fraction of contributing water dipoles to the measured spectra were compared using the experimental data. The results of the two expressions differed by approximately 20% in their estimation of unbound, participative water and both suggest that the water relaxation process is slowed for the absorbed water in comparison to free, or bulk, water. The shift in the measured spectra for the water/POM system is attributed to the steric hindrances imposed on the water molecules by the hydrogen bonds formed with the polymer molecules. The effects of water sorption by POM were used to derive the associative effects on antenna performance for a hypothetical microstrip antenna comprised of a dielectric layer of POM. It was found that the resonant frequency decreased by 7.5% for a water uptake of 1.65 weight percent 相似文献
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Toshiaki Sakuyama Yasunori Tanaka Yoshihiko Uesugi Shuhei Kaneko Shigemitsu Okabe 《Electrical Engineering in Japan》2012,178(2):11-20
The plasma‐quenching efficiency of the ablated vapor of polymers containing nitrogen atoms was numerically investigated by the inductively coupled thermal plasma technique. Polyamide66 (PA66), which contains nitrogen atoms, was used as a polymer material, and was injected into Ar thermal plasma in a numerical simulation. The simulation model considered heating, melting, and evaporation of polymer powders, and then plasma‐quenching phenomena due to polymer ablation. The thermodynamic and transport properties of the ablated vapor were also taken into account. It was found that PA66 vapor has a greater plasma‐quenching efficiency than other polymer materials of PTFE, POM, PMMA, and PE. The calculated results were confirmed to be valid by comparison with experimental results in terms of the ablated vapor distribution and powder velocities. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 178(2): 11–20, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21185 相似文献
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不同因素对气吹式塑壳断路器开断电弧运动影响的实验研究 总被引:7,自引:6,他引:7
设计了用于研究气吹式塑壳断路器开断电弧运动情况影响因素的实验模型。利用具有自聚焦透镜及图形组态功能的二维光纤快速测试系统测取了不同情况下开断10kA预期电流时的电弧电流、电弧电压、灭弧室气压波形,以及开断过程的电弧运动图景。对比研究了灭弧室上下方气体阻尼、栅片结构及产气材料等因素对气吹灭弧性能的影响情况。结果表明,尽可能封闭灭弧室下方出气口,采用短栅片结构和POM与尼龙产气材料均有利于电弧进入灭弧室。 相似文献
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The influence of polymer ablation on arc properties such as the temperature distribution and arc conductance in the current decay process was investigated by numerical approaches. A numerical thermofluid model was developed for a simplified circuit breaker with POM or PTFE ablation. In this model, thermal plasma‐polymer solid coupling phenomena such as melting and evaporation were taken into account without any empirical model based on measurements, unlike other existing numerical thermofluid models. The dominant process for the decay of arc conductance was examined by changing the thermodynamic parameters such as the melting and boiling temperatures of solid polymers, or the thermal conductivity and electrical conductivity of the ablation gas. It was found that the gas density, thermal conductivity, and electrical conductivity of the ablation gas were more effective for decaying arc conductance than any other thermodynamic parameters. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 180(3): 32–45, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22274 相似文献
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从低压电器行业概论、主要产品的产量及其技术水平、产品设计与制造、产品进出口及市场情况等方面简要分析了我国低压电器行业现状.介绍了国外著名低压电器制造商最新产品的发展情况.在此基础上详细分析了我国低压电器新一代主要产品的研究重点和发展方向.提出了现场总线与可通信低压电器相关产品的总体发展目标与近期主要任务.上述两部分产品的组合将成为我国第四代低压电器产品. 相似文献
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我国低压电器行业现状与发展趋向 总被引:8,自引:7,他引:8
从低压电器行业概论、主要产品的产量及其技术水平、产品设计与制造、产品进出口及市场情况等方面简要分析了我国低压电器行业现状.介绍了国外著名低压电器制造商的最新产品的发展情况.在此基础上详细分析了我国低压电器新一代主要产品的研究重点和发展方向.提出了现场总线与可通信低压电器相关产品的总体发展目标与近期主要任务.上述两部分产品的组合将成为我国第四代低压电器产品. 相似文献
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铅蓄电池无镉板栅取代含镉板栅势在必行 总被引:1,自引:1,他引:0
按正极板栅采用的合金材料不同,电动自行车用阀控铅蓄电池可分为用铅锑镉合金的“含镉产品”和用铅钙锡铝合金的“无镉产品”。叙述了电动自行车用阀控铅蓄电池的“含镉产品”和“无镉产品”发展过程及其优缺点。指出了由“含镉产品”向“无镉产品”的转变已势在必行。介绍了制造长寿命“无镉产品”的主要措施。 相似文献