PS/PVA包装片材的制备及其力学性能研究

采用复配增塑剂丙三醇和乙二醇对聚乙烯醇（PVA）进行改性,实现熔融加工;然后通过熔融共混方法与聚苯乙烯（PS）共混,制备具有吸湿功能的PS/PVA包装片材,并对该共混片材的力学性能进行实验研究。实验结果表明：当复配增塑剂丙三醇和乙二醇的质量比为4：1,复配增塑剂的用量为50phr时,可很好地实现PVA熔融加工效果;当PS与PVA质量比为6：4时,干燥片材的力学性能最好;在不同湿度下,吸湿7天后,其力学性能有显著变化。     

我国苯乙烯生产消费现状及市场前景

乙烯(SM)是一种重要的基本有机化工原料，主要用于生产聚苯乙烯树脂(PS)、丙烯腈-丁二烯-苯乙烯三元共聚物(ABS)、苯乙烯-丙烯腈共聚物(SAN)树脂、离子交换树脂、不饱和聚酯以及苯乙烯系列橡胶(SBR、SBS)等。此外。还可用于制药、染料、农药以及选矿等行业。用途十分广泛。     

线性高分子材料改性与载体的选择

结合聚合和加工成形技术,以及材料工程骨架-载体机理,研究了线性高分子的4种不同的改性载体,即线性高分子-载体共混型、线性高分子共混型、线性高分子聚合型和线性高分子-载体坯基涂层型,并阐述了载体的效能、稳定性、相容性、几何尺寸、安全性和成本等影响改性效果的主要因素。文章指出：在高分子改性材料研发、生产和国家标准的制定方面,应当对其毒性和安全防护予以重视。     

废旧聚苯乙烯回收制备胶粘剂方法

鉴于聚苯乙烯分子链的刚性，可以采用共混、接枝、镶嵌等方法，选择适当的改性剂改性废旧聚苯乙烯为胶粘剂。     

苯乙烯国内外生产技术进展

苯乙烯(SM)是一种重要的基本有机化工原料，主要用于生产聚苯乙烯树脂(PS)、丙烯腈一丁二烯一苯乙烯(ABS)树脂、苯乙烯一丙烯睛共聚物(SAN)树脂、丁苯橡胶和丁苯胶乳(SBR／SBR胶乳)、离子交换树脂、不饱和聚酯以及苯乙烯系热塑性弹性体     

聚苯乙烯市场前景堪忧

聚苯乙烯（PS）是一种热塑性树脂，为无色、无臭、无味而有光泽的透明晶体。具有耐化学腐蚀性、耐水性和优良的电绝缘性和高频介电性，缺点是耐热性低、耐光性差、性脆，易发生应力开裂。PS有四种主要类别：GPPS（通用级PS树脂）、HIPS（抗冲级PS树脂）、EPS（可发泡PS树脂）和SPS（间规PS树脂）。PS的生产方法有本体法、悬浮法和溶液法三种。其中本体法聚合工艺是工业上生产PS的主要方法。     

PI让化工生产实时可见——从上海赛科看PI系统在化工行业的应用

上海赛科石化有限责任公司(以下简称赛科)位于上海曹泾化学工业区,是目前中国最大的合资石化公司(其中,BP占50%的股权,中石化占30%的股权,上海石化占20%的股权)。它除了拥有90万吨/年乙烯裂解装置(年产90万吨乙烯和60万吨丙烯)外,还包括产能60万吨/年的全密度聚乙烯(PE)装置、25万吨/年的聚丙烯(PP)装置、50万吨/年的芳烃装置、50万吨/年的苯乙烯单体(SM)装置、26万吨/年的丙烯腈(A N)装置、30万吨/年的聚苯乙烯(PS)装置和9万吨/年的丁二烯装置。赛科建设于2004年末竣工,并于2005年3月投产。赛科不只规模之大让惊讶,其管理更有独到之处…     

前景广阔的双向拉伸聚苯乙烯加工技术

聚苯乙烯 (PS)是一种热塑性塑料产品,其主要特点有：无毒、无味、高透明度、质硬且脆、强度刚度大、化学性能稳定、电绝缘性好、易加工成型。自 20世纪 30年代 PS问世以来,便迅速成为总产量居第三位的塑料产品。由于 PS的高透明度和较好的刚性,无毒无味,不改变食品味道和药品的质量,再加上它的比重只有 1.05(PET为 1.45, PVC为 1.37),又可以回收利用,焚烧过程不会产生有毒物质,所以在包装领域有着极大的使用价值。 BOPS片材是利用双向拉伸工艺、改善 PS的脆性,增加它的机械性能,获得高透明 (>90％ )高表面光泽度的塑料片…     

UHMWPE对UHMWPE/UHMWPP共混冻胶纤维性能的影响

研究了超高分子质量聚乙烯（UHMWPE）对超高分子质量聚丙烯（UHMWPP）／UHMWPE共混冻胶纤维结晶性能、热学性能、形态结构以及力学性能的影响。结果表明：随着UHMWPE含量的增加，共混纤维结构具有更好的连贯性，并显示出较好的热学性能；当UHMWPE含量超过一定比例时，虽然共混纤维的热学性能下降，但在共混纤维中呈现出明显的类似“钢筋混凝土”结构，从而大大地提高了共混纤维的力学性能。     

我国苯乙烯市场产不足需

苯乙烯是苯最大用量的衍生物，也是最基本的芳。烃化学品。苯乙烯主要用于生产聚苯乙烯(占其需求量的2／3)，也可用于制取苯乙烯-丁二烯(丁苯)橡胶(SBR)、ABS和苯乙烯-丙烯腈(SAN)树脂、不饱和聚酯等。此外，也是生产涂料、染料、合成医药的重要原料。     

框架-剪力墙-薄壁筒斜交结构自由振动分析的状态空间法

采用沿高度方向连续化的方法,建立了框架-剪力墙-薄壁筒斜交结构自由振动分析的连续化计算模型。将沿高度方向的坐标虚拟成时间坐标,导出了问题的状态空间表达式,用状态空间理论的方法求出了状态向量表达式,由结构的边界条件可求出初始状态向量,从而得出结构的自振频率。给出了数值算例,并与其他算法的结果进行了比较。     

How can the EU climate targets be met? A combined analysis of technological and demand-side changes in food and agriculture

To meet the 2 °C climate target, deep cuts in greenhouse gas (GHG) emissions will be required for carbon dioxide from fossil fuels but, most likely, also for methane and nitrous oxide from agriculture and other sources. However, relatively little is known about the GHG mitigation potential in agriculture, in particular with respect to the combined effects of technological advancements and dietary changes. Here, we estimate the extent to which changes in technology and demand can reduce Swedish food-related GHG emissions necessary for meeting EU climate targets. This analysis is based on a detailed representation of the food and agriculture system, using 30 different food items.We find that food-related methane and nitrous oxide emissions can be reduced enough to meet the EU 2050 climate targets. Technologically, agriculture can improve in productivity and through implementation of specific mitigation measures. Under optimistic assumptions, these developments could cut current food-related methane and nitrous oxide emissions by nearly 50%. However, also dietary changes will almost certainly be necessary. Large reductions, by 50% or more, in ruminant meat (beef and mutton) consumption are, most likely, unavoidable if the EU targets are to be met. In contrast, continued high per-capita consumption of pork and poultry meat or dairy products might be accommodated within the climate targets. High dairy consumption, however, is only compatible with the targets if there are substantial advances in technology. Reducing food waste plays a minor role for meeting the climate targets, lowering emissions only by an additional 1–3%.     

基于Stacking模型融合的店铺销量预测

为了实现企业产品销量预估,提高生产供应的准确性与效率,提出了基于Stacking模型的融合算法进行销量预测。算法设计了两层堆叠的模型结构,初级学习器采用随机森林、支持向量回归、差分整合移动平均自回归、轻量级梯度提升机器和门控循环单元5种单模型,将分类与回归树作为次级学习器构成Stacking融合模型,并对数据进行了预测。预测结果显示,使用Stacking模型融合后得到了较好的预测结果,比单模型中效果最好的模型的均方根误差更小,平均绝对误差更小,决定系数值更大,表明Stacking融合模型的预测准确率更高。所设计模型可用于对企业店铺的产品销量进行预测,帮助企业更好地安排生产、营销活动,为减少库存、缩短生产销售周期提供数据支持,对企业生产决策有一定的参考价值。     

在涂布纸上喷墨印刷P3HT及其润湿性和印刷品质的研究

近年来,低成本的纸和类纸基材已被广泛应用于各种印刷电子领域。以纸或类纸为基材,采用功能墨水（如导电聚合物、半导电聚合物和碳纳米管）可以制备诸如晶体管、电容和感应器等电子元件。目前的相关报道很多,如在报纸上印制有机光电二极管,在微生物纤维素膜上印制电子纸显示器,在纸基上印制可折叠热致变色显示器及在真空沉积聚对二甲苯涂层纸张上印制高性能有机薄膜晶体管阵列。     

余能原理基面力元法在桁架大变形分析中的应用

为了对桁架弹性大变形问题进行针对性研究,对平面二维问题的基面力单元模型进行了改进,把平面四边形四边中节点基面力单元退化为平面二节点桁架基面力单元,推导了桁架大变形余能原理控制方程和单元轴力、节点位移表达式,根据由控制方程得出的桁架大变形问题的非线性方程组,利用Matlab语言编制了基面力元程序,计算了桁架结构几何非线性算例。与大型通用有限元软件ANSYS的计算结果进行了对比分析,所用方法的结果与理论解一致,与ANSYS的计算结果相差较小。因此可得结论:所介绍的基面力元模型是可靠的,可以应用于对桁架结构的几何非线性问题分析,具有较广阔的前景。     

加筋聚苯乙烯轻质膨胀土室内试验研究

为了研究加筋聚苯乙烯轻质膨胀土的膨胀与强度特性,将聚苯乙烯颗粒与膨胀土混合,聚丙烯纤维作为加筋材料,开展了包括密度、无荷膨胀率、膨胀力以及饱和快剪等室内试验。结果表明,聚苯乙烯颗粒和聚丙烯纤维的掺入可有效抑制膨胀土的膨胀特性,表现为无荷膨胀率与膨胀力的显著减小;聚苯乙烯颗粒主要起到体积置换作用,土样密度以及膨胀力随聚苯乙烯颗粒掺量增加线性减小;随着聚苯乙烯颗粒的增加,混合土内摩擦角持续增大,黏聚力先增加后降低;随着纤维掺量的增加,混合土的黏聚力得到有效增长。因此,加筋聚苯乙烯轻质土在改良膨胀土方面具有良好的应用价值。     

Engineering controls to minimize worker exposure to ethylene oxide at sterilization facilities

Gas sterilizers, using either pure ethylene oxide (EtO) or an admixture with an inert diluent, are typically utilized for treating products which cannot withstand heat sterilization. Due to the highly toxic nature of ethylene oxide and its classification as a suspect carcinogen, special precautions must be taken to ensure safe exposure levels to human receptors. This paper discusses the various engineering controls that can be implemented at EtO sterilization facilities to minimize ethylene oxide ambient concentrations and worker exposure levels.     

Safe storage of dilute ethylene oxide mixtures in water

In the past industry has had to rely on a number of “rules of thumb” to provide a means of reasonable analysis for many design, operation, safety and similar issues. The lack of readily available computing facilities made the use of “rules of thumb” a necessary part of doing business in the hydrocarbon processing industry. And these “rules of thumb” have proven useful and allowed many tasks to be accomplished successfully. Today, however, availability of mainframe computers or desktop computing facilities has provided a tool that has decreased the need to rely on “rules of thumb.” And in many cases processing improvements can only be accomplished by replacing “rules of thumb” with more rigorous analysis. In the ethylene oxide producing/consuming industry a widely-used “rule of thumb” concerns the storage of ethylene oxide water solutions. A well-publicized “rule” stated that solutions in excess of 1-2 weight percent ethylene oxide in water should not be stored [1]. This “rule” is certainly valid in many situations. However, this guideline may be unnecessarily restrictive in other cases. The impact of several key process parameters impacts the amount of ethylene oxide in water than can be safely stored. This study will show that higher concentrations of ethylene oxide in water can be safely stored under the right circumstances. The study will also discuss the key variables that determine whether aqueous ethylene oxide solutions can be safely stored. Finally, a methodology used in determining how much ethylene oxide in water can be safely stored will be outlined.     

Self- and collective-interests: Using formal network activities for developing firms' business

Many inter-firm network initiatives supported by government funds are based upon the idea that benefits rise incrementally as more actors connect with each other. This paper takes the stand that self-interest and collective-interest are evident in how firms participate in network activities, and how these activities are related to the development of the network. A time-flow model is presented of firms' participation and activities in a network according to specific blends and understandings of self- and/or collective-interest. The way the network is formed also shapes managerial understanding of why firms participate in activities and how self- and collective-interests coincide. A qualitative study in the Danish food industry establishes that every firm views business network activities as important, but each engages differently in these activities. The results of this study reveal interesting patterns between self- and collective-interests for those participating in network activities and the resulting network development. A key finding of this study is the importance of a firm's ability to convert the collective-interest of joint network activities into self-interest gains for the firm. This ability is proposed as an additional network competence to those already present in the literature.     

Labor Law Reform: One Step Forward and Two Steps Back

This article deals with the question of whether the reforms proposed by the labor law traditionalists are desirable on economic grounds, and if not, what types of reform might be offered. The specific proposals include increased job security, increased employee participation in decision making, and reform of the National Labor Relations Act (NLRA). The difficulty for reformers is that they have not yet accepted the challenge of designing proposals for today's more competitive labor and product markets. Until this changes, reform efforts can be shown to be backward steps.