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型坯温差法优化挤出吹塑中空工业制件壁厚分布的研究 总被引:1,自引:0,他引:1
黄虹;龙婷;王选伦;邱方军 《中国塑料》2011,25(2):68-71
以典型复杂中空工业制件为研究对象,根据聚合物流变学原理,提出了用型坯温差法来优化挤出吹塑中空工业制件壁厚分布的均匀性:在型坯挤出或型坯吹胀之前,采用水或者空气强制冷却变形较大部位对应的型坯,使局部温度迅速降低,使型坯具有一定的温度梯度。结果表明,用型坯温差法优化后的吹塑成型油箱壁厚分布标准差由0.7249减小为0.4475、0.4582,壁厚均匀性明显得到改善,验证了利用型坯温差法优化油箱制件壁厚分布均匀性的方法是可行的。 相似文献
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塑料挤出吹塑中空成型壁厚均匀性的控制 总被引:1,自引:0,他引:1
吴裕农;王树辉;许中明 《中国塑料》2011,25(1):106-109
通过对挤出吹塑中空成型设备增设壁厚自动调节装置、对型坯挤出模头结构进行改进以及对全工作过程采用闭环自动控制,可以大大提高中空成型制件壁厚均匀性。改进后设备的生产效率提高,成型制品的单件质量、质量偏差及平均能耗降低,实现了塑料挤出吹塑中空成型技术的重点突破,达到国内领先并接近国际先进水平。 相似文献
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吨包装内胆挤出吹塑成型型坯吹胀的数值模拟 总被引:1,自引:0,他引:1
针对吨包装内胆挤出吹塑型坯吹胀阶段的成型工艺,采用Workbench-Polyflow分析软件实现型坯吹胀模拟。建立型坯及模具的几何模型和网格模型;利用Polyflow中的参数渐进方法建立型坯吹胀阶段中的模具闭合运动模型。获得型坯在吹胀过程中的型坯轮廓曲线分布以及吹胀完毕后的型坯壁厚分布;分析了模具运动速度和吹胀压力对型坯与模具的接触时间、吹胀时间及壁厚的影响。 相似文献
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使用计算流体力学软件(POLYFLOW),在温度和吹气压力相同的条件下,分别数值模拟了均一壁厚初始型坯和优化的非均一壁厚初始型坯挤出吹塑高密度聚乙烯(HDPE)带把手油桶的过程。用POLYFLOW软件中的型坯控制程序,将初始型坯分成10段,通过控制这10段型坯的厚度来控制吹塑制品的壁厚。结果表明:均一壁厚5.0 mm的初始型坯经过吹胀阶段后,油桶大部分壁厚都小于3.0 mm;使用POLYFLOW后处理程序对油桶型坯6次优化后,吹塑制品壁厚均大于3.0 mm,且在第4次优化的基础上将油桶质量从646.89 g降至642.68 g。 相似文献
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在中空塑料容器的挤出吹塑成形工艺中,型坯壁厚控制技术是关系产品质量的关键技术之一。为此本文介绍一种应用微机控制型坯壁厚的新方法。 相似文献
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将支持向量机应用于挤出吹塑过程的一段型坯壁厚分布的预测,并将预测结果与人工神经网络预测的结果进行比较,验证了支持向量机具有更强的泛化能力。 相似文献
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为掌握佛山市顺德新城区降水中污染物的情况,2015年7月至8月,文章作者分别在雨天进行了降水取样,对降水中的pH、电导率、常见阴离子(F-、Cl~-、NO_3~(2-)、SO_4~(2-))及部分重金属(铅和镉)进行监测分析。选择有相关数据的珠江三角洲和石家庄、厦门等地的降水中污染物的情况进行对比。结果表明,顺德新城区降水中的p H和部分阴离子浓度优于珠江三角洲平均值,酸雨类型属于硫酸和硝酸混合型;其水体洁净程度略差于石家庄;铅和镉的浓度也高于厦门,甚至部分超出了人体能直接接触的安全范围。 相似文献
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Saturated very long chain fatty acids (fatty acids with greater than 22 carbon atoms; VLCFA) accumulate in peroxisomal disorders,
but there is little information on their turnover in patients. To determine the suitability of using stable isotope-labeled
VLCFA in patients with these disorders, the metabolism of 22-methyl[23,23,23-2H3]tricosanoic (iso-lignoceric) acid was studied in rats in vivo and in human skin fibroblasts in culture. The deuterated iso-VLCFA was degraded to the corresponding 16- and 18-carbon iso-fatty acids by rats in vivo and by normal human skin fibroblasts in culture, but there was little or no degradation in peroxisome-deficient (Zellweger’s
syndrome) fibroblasts, indicating that its oxidation was peroxisomal. Neither the 14-, 20-, and 22-carbon iso-fatty acids nor the corresponding odd-chain metabolites could be detected. In the rat, the organ containing most of the iso-lignoceric acid, and its breakdown products, was the liver, whereas negligible amounts were detected in the brain, suggesting
that little of the fatty acid crossed the blood-brain barrier. Our data indicate that VLCFA labeled with deuterium at the
ω-position of the carbon chain are suitable derivatives for the in vivo investigation of patients with defects in peroxisomal β-oxidation because they are metabolized by the same pathways as the
corresponding n-VLCFA. Moreover, as iso-VLCFA and their β-oxidation products are readily separated from the corresponding n-fatty acids by normal chromatographic procedures, the turnover of VLCFA can be more precisely measured.
A preliminary report of part of this work (Reference 18) was presented at the 5th International Symposium on the Synthesis
and Applications of Isotopes and Isotopically Labelled Compounds, Strasbourg, France, June 20–24, 1994. 相似文献
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高效液相色谱法分析化妆品中微量成分的研究进展 总被引:1,自引:0,他引:1
综述了高效液相色谱法在化妆品中防腐剂、防晒剂中紫外线吸收剂以及性激素的检测等几个方面的应用;同时,介绍了分析所用的色谱柱、流动相、使用的检测手段以及样品的提取方法;最后针对目前存在的问题,提出了高效液相色谱用于化妆品中微量成分分析的研究方向和发展前景。 相似文献
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H. Toda Y. Mochizuki T. Kawanishi H. Kawashima 《Nutrient Cycling in Agroecosystems》2002,63(2-3):167-173
In a coastal agricultural area in the central part of Japan (Shizuoka), we found decreasing nitrate concentration with depth in a shallow groundwater, where the depth to water table varied between 0.6 and 1.2 m below ground surface. High nitrate concentrations (5–29 mg N L–1) were often observed in the upper layer (0–2 m) of the groundwater, but the concentration decreased to less than 1 mg N L–1 in the deeper layer. Ammonium was scarcely detected, and the concentration of dissolved oxygen was usually low (< 1 mgO2 L–1) in the groundwater. Nitrate in the groundwater often had very heavy nitrogen stable isotope ratios (>20{}). There was a negative relationship between nitrogen stable isotope ratio of nitrate and its concentration. When nitrate was injected into the groundwater with acetylene and bromide (a conservative tracer), nitrate concentration decreased to 20% of the initial level within 5 days, accompanied by the increase in nitrite and nitrous oxide concentration and a little change in bromide concentration. These results indicate that microbial denitrification plays a potential role in the decrease of nitrate in shallow groundwater at the study site. 相似文献
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我国硝酸工业生产技术新进展 总被引:1,自引:0,他引:1
系统叙述了我国硝酸工业2000-2007年生产现状及主要技术成果,尤其指出了国产"四合一"机组的成功投运,使我国硝酸国产化装置取得较大的进步,表现在吨酸的铂耗、氨耗和能耗等方面接近国外引进装置水平,同时介绍了国外双加压法硝酸生产技术的进展.我国已成为硝酸生产大国,仍需以先进的技术改造和发展我国硝酸工业,确保我国硝酸工业健康有序地发展,加快从硝酸生产大国向强国迈进的步伐. 相似文献