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121.
农用聚乙烯调光膜的研制 总被引:9,自引:0,他引:9
本文介绍农用聚乙烯调光膜的制造、性能和应用。通过将稀土络合物调光剂和其他功能助剂添加到聚乙烯树脂中,经挤出塑化吹胀成型制得调光膜。膜的拉伸强度(纵/横)、断裂伸长率(纵/横)和直角撕裂强度(纵/横)分别为17.2/16.1MPa、413/457%、81/86kN;用红、兰、绿色调光剂可分别制得主峰波长为616nm的红光膜、436nm的兰光膜和540nm的绿光膜,其中以红光膜最佳。经农田实际应用表明 相似文献
122.
粉煤灰物理序参量的系统化 总被引:1,自引:1,他引:1
近年来,作者等通过系列的粉煤灰特征化和系统化基础研究,形成了粉煤灰物理序参量系统。这个系统的实用性是能够提供大量有序信息,故称之为“脉搏系统”。本文介绍了粉煤灰物理序参量系统的构建。此系列的应用有助于粉煤灰资源开发及有利于粉煤灰质量从无序状态到相对稳定和有序状态的发展。 相似文献
123.
Acrylonitrile–EPDM–styrene (AES) graft copolymers were synthesized by solution graft polymerization of styrene (St) and acrylonitrile (AN) onto EPDM in an n‐hexane/benzene solvent with benzoyl peroxide (BPO) as an initiator. The structure changes were studied by an FTIR spectrophotometer. The grafting parameters were calculated gravimetrically. The influence of the polymerization conditions, such as the reaction time, concentration of the initiator, EPDM content, and weight ratio of St/AN, on the structure of the products was investigated. It was found that a proper initiator concentration and EPDM content will give a high grafting ratio of the AES resin. The thermal property of the copolymer was studied using programmed thermogravimetric analysis (TGA). The results showed that the copolymer has a better heat‐resistant property than that of ABS, especially for the initial decomposition temperature (Tin) and the maximum weight loss rate temperature (Tmax). Also, the mechanism of the graft reaction was discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 428–432, 2002 相似文献
124.
Hongyi Zhou 《应用聚合物科学杂志》2004,92(6):3901-3909
Efforts to evaluate interlayer adhesion of coextruded films are often hampered by the inability to initiate delamination. On the other hand, interlayer delamination was often noticed at cut or trimmed edges of coextruded films. In this study, a test method was developed by first initiating delamination by uniaxial stretching and then measuring interlayer adhesion by peel test. Delamination was initiated by uniaxial stretching under controlled conditions for samples with double‐neck geometry. The double‐neck geometry was designed to create a specimen for the subsequent 180° peel test. Peel force was used to quantify interlayer adhesion of coextruded films based on polycarbonate and its copolymers. With this two‐step technique, coextruded films with peel force as high as 5300 N/m or 30 lb./in. were quantified. In addition, effects of copolymer composition and coextrusion processing condition on interlayer adhesion of these coextruded films were clearly demonstrated. A great deal of variation of interlayer adhesion across film surface was also revealed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3901–3909, 2004 相似文献
125.
126.
Artificial neural network approaches on composition-property relationships of jet fuels based on GC-MS 总被引:3,自引:0,他引:3
The relationships of composition-properties of 80 jet fuels concerning chemical compositions and several specification properties including density, flashpoint, freezing point, aniline point and net heat of combustion were studied. The chemical compositions of the jet fuels were determined by GC-MS, and grouped into eight classes of hydrocarbon compounds, including n-paraffins, isoparaffins, monocyclopraffins, dicyclopraffins, alkylbenzens, naphthalenes, tetralins, hydroaromatics. Several quantitative composition-property relationships were developed with three artificial neural network (ANN) approaches, including single-layer feedforward neural network (SLFNN), multiple layer feedforward neural network (MLFNN) and general regressed neural network (GRNN). It was found that SLFNNs are adequate to predict density, freezing point and net heat of combustion, while MLFNNs produce better results as far as the flash point and aniline point prediction are concerned. Comparisons with the multiple linear regression (MLR) correlations reported and the standard ASTM methods showed that ANN approaches of composition-property relationships are significant improvement on MLR correlations, and are comparable to the standard ASTM methods. 相似文献
127.
综述了单螺杆挤出机内聚合物熔体层流混合机理的研究进展,对提高混合的措施进行了分析总结,指出了进一步强化混合效果的方法。 相似文献
128.
129.
针对水文变异引发的基于水文统计学的生态保障流量分析方法在实践应用上存在的问题,提出通过水文变异点分析找出受环境变化影响的转折年,以该年份之前的水文序列计算生态系统需要的保障流量的思路,可有效避免因水文变异而导致的水文统计学方法失效问题。以渭河中下游为例,通过累积曲线法和Mann-Kendall(M-K)检验法对渭河干支流7个关键控制断面进行水文变异点识别,并以此为基础,应用改进Tennant法计算渭河中下游各控制断面的生态低限流量与适宜生态流量。该成果可作为渭河开展流域综合治理和生态保护的参考数据。 相似文献
130.
建立了混沌单螺杆挤出机计量段物理和数学模型。定义了更合理的边界条件,采用Carreau本构方程,采用有限体积方法对聚合物熔体在螺槽内流动的周期性效应进行了数值模拟分析。得到了不同位置的速度分布细节以及流体示踪粒子的行为轨迹。发现螺槽内速度分布表现出周期性和对称性的变化,揭示了同宿点及椭圆点存在及位置不变性,为进一步分析流体质点在相空间的动力学行为奠定了基础。 相似文献