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81.
Evaluation of the aging behavior of ethylene copolymer films for solar applications under accelerated weathering conditions 总被引:1,自引:0,他引:1
Ethylene copolymers based on acrylic acids and acrylates are an interesting alternative to ethylene(vinylacetate) (EVA) for photovoltaic (PV) encapsulation. These materials provide similar or better mechanical and optical properties and a slightly better aging behavior, but without the formation of corrosive acetic acid during aging, which is particularly of importance in PV applications. The focus of the research work was to evaluate and screen the aging behavior of ethylene copolymers containing different types of comonomers for solar applications. To investigate the intrinsic weathering behavior of the materials, unstabilized films with comonomer contents around 10% were exposed to temperature, humidity and solar radiation. Special attention was given to the optical and mechanical properties. All investigated films showed high transparency in the solar range with hemispheric transmittance values above 91%. Regarding mechanical properties, the ethylene copolymer films exhibited a highly ductile behavior and high flexibility. Similar degradation behavior could be observed for all investigated films. Due to formation of chromophoric degradation products, yellowing could be observed and hemispheric transmittance values dropped slightly to values between 88.5 and 90.5%. The unstabilized films showed significant embrittlement due to weathering. After 750 h of weathering both strain-at-break and stress-at-break values of all ethylene copolymer films dropped significantly below 50% of the initial values. 相似文献
82.
83.
主要介绍了柴油降凝剂ESMVA的合成和使用条件的考查.ESMVA降凝剂是以马来酸酐、醋酸乙烯酯、十四醇为原料,以苯和甲苯为溶剂,以偶氮二异丁腈为引发剂,以对甲苯磺酸为催化剂,在138℃下反应6h制得。该剂对锦州六厂0#柴油的纯降凝度可达14~23℃,冷滤点降低2~4℃;东炼0#柴油纯降凝度达16~30℃,冷滤点降低2℃.另外还分析了ESMVA型降凝机理. 相似文献
84.
为了寻找新的99Tcm N 标记的心肌显像剂,合成了两种含有酯基的NS配体半胱氨酸甲酯(CYM)和半胱氨酸丙酯(CYP)。以SnCl2 为还原剂,H2NNH- (C= S)- SCH3 为N3- 给予体,通过交换反应制备了放化纯大于90% 的99Tcm N(CYM)2 和99Tcm N(CYP)2。探讨了pH值和反应时间对99Tcm N配合物放化纯的影响,并对其在小鼠体内的生物分布进行了研究。结果表明,99Tcm N(CYM)2 和99Tcm N(CYP)2在心肌中具有较高的初始摄取和快速的血清除,血半清除期小于15m in。但是,心肌滞留不理想,心肌与其它组织的放射性比值较低。本工作对于设计新的99Tcm N心肌显像剂具有参考价值。 相似文献
85.
乙烯装置混合碳五的综合利用 总被引:1,自引:0,他引:1
介绍了北京东方石化公司东方化工厂乙烯装置中汽油加氢工艺、碳五分离工艺的特点,并且对碳五分离后产品的性质和用途进行了分析。 相似文献
86.
87.
在常压、313-413K下,采用NDJ-1旋转式黏度计,测定了含NY2催化剂的乙二醇和二甘醇的黏度.采用黏度Andrade关系式,将黏度数据与NY2催化剂质量分数和温度进行关联,得到经验关系式.结果表明,由经验方程计算值与实验结果基本相符,为催化水合制乙二醇的反应器设计和优化分离设备提供必要的基础数据. 相似文献
88.
Lithium-doped sulfated-zirconia catalysts for oxidative coupling of methane to give ethylene and ethane 总被引:1,自引:0,他引:1
Li-doped sulfated-zirconia catalysts were found to be effective for oxidative coupling of methane (OCM). The catalyst performances depend on the sulfate content and calcination temperature. A maximum C2 yield is attained over the catalysts, which contain 6 wt.% sulfate and calcined at 923–973 K, being closely related to the preparation conditions of sulfated-ZrO2 as solid super-acids. When the performances of the Li-doped sulfated-ZrO2 (Li/SZ) catalysts were tested at 1023 K as a function of reaction time, both the C2 and COx selectivities remained constant over the range of 8 h, but the CH4 conversion decreased from 17.5% to 11.9%. The nature of Li/SZ catalysts for the OCM was investigated by X-ray diffraction, XPS, and NH3 and CO2 TPD measurements. It could be postulated that the sulfated-ZrO2 surface could play an important role in the formation of a catalytically active structure by Li-doping. 相似文献
89.
A multiphase Volume‐of‐fluid (VOF) model was developed to gain further insights into the reactive flow parameters and electrical capacitance tomography (ECT) measurements on the remediation of hazardous organic pollutants. Low ozone bubble frequencies were obtained for high surface tension fluids, and the liquid viscosity affected the ozone bubbling frequency. The VOF model indicated that the increase of inlet gas velocity enriched the ozone bubble detachment and concomitantly generated larger ozone bubbles, decreasing the detoxification rates. VOF mappings and ECT visualizations of gas‐liquid unveiled preferential routes and highlighted the attenuation of the axisymmetric behavior of the ozonation bubble column under high‐interaction regimes. 相似文献
90.
介绍环氧乙烷操作风险以及导致环氧乙烷在典型乙氧基化反应器中没有有效的气相循环或没有气相循环操作条件下分解的主要原因。环氧乙烷在密闭乙氧基化反应器中达到爆炸极限时,是可以通过控制反应器中氮气浓度避免事故发生。 相似文献