劣质原油加工过程中重金属镍、钒迁移分布规律研究

以某加工高硫劣质原油的石化企业为研究对象,采集了该企业原油、中间馏分油、废水、固体废物及石油焦等样品,利用原子吸收技术对不同样品中所含重金属镍、钒含量进行了分析测定,探讨了典型高硫劣质原油中重金属镍、钒在石油加工过程中的迁移分布规律。结果表明,重金属镍、钒主要分布在重馏分中,在加工过程中会进一步集中于石油焦产品和固体废物中,为我国未来劣质原油加工过程的重金属镍、钒控制提供数据支持和参考。     

食品接触材料安全性研究进展与相关法规

介绍了食品接触材料特定迁移物等影响材料安全性的物质,以及在食品接触材料使用和加工过程中产生的不安全因素,综述了欧盟、美国等发达国家的法规控制情况以及我国法规现状。     

聚酯型PVC加工助剂的研制

本文介绍了SZh 4202聚酯型改性剂的合成、性能及用途。该产品的耐迁移、耐抽出性能优良。在PVC制品的加工过程中,它具有提高加工速度、降低塑化温度的功效,其制品表面平滑,并具有光泽。     

土壤中芳香烃的测定

1 引言 芳香烃是一类主要环境污染物,主要来自煤、石油等矿物性燃料的加工过程,当它们进入土壤时,会造成土壤污染。山西是能源重化工基地,煤加工量大。因此,测定土壤中芳香烃的含量对研究它的迁移、转化、规律具有一定的意义。2 实验部分     

微波条件塑料包装化学物质迁移研究

塑料广泛应用食品于食品包装中,并且常常会在塑料包装加工过程中添加许多化学添加剂以提高其性能,可能会对人的健康产生影响。就微波条件下塑料包装化学物质的迁移进行了研究,采用500,700,900W三个不同加热功率下分别对食品模拟物三种食用油(橄榄油、菜籽油和葵花籽油)的迁移率进行实验。以期对预防塑料包装危害产生积极影响。     

苯并三唑类紫外线吸收剂的现状及发展趋势

综述了不同种类的紫外线吸收剂,着重介绍了苯并三唑类紫外线吸收剂。苯并三唑类紫外线吸收剂由于性能优异而广泛应用于各种高分子合成材料和制品中。但由于其相对分子质量较小,在高分子材料加工过程中,容易通过向表面迁移、表面挥发而引起损失,所以其耐光性比较差。在苯并三唑类紫外线吸收剂分子中引入可聚合的基团使它可以和不同的单体聚合成高分子化合物。从共价键到聚合物链的转变使其在介质中更稳定,更不易迁移和挥发。含有可聚合基团的紫外线吸收剂相比普通的紫外线吸收剂显示出了相当优良的耐光稳定性。     

再生聚酯纤维中的重金属锑的析出研究

利用电感耦合等离子体原子发射光谱仪分析了再生聚酯纤维及其原料和加工过程中的重金属锑含量,通过模拟汗液研究了再生聚酯纤维中锑析出的影响因素。结果表明:废旧聚酯泡料中锑的含量为160.43μg/g,远大于瓶片料中的锑含量111.25μg/g和原生切片中的锑含量96.75μg/g;在利用泡料制备再生聚酯纤维的加工过程中,熔体输送阶段锑含量变化不明显,而纺丝后锑含量显著下降为109.53μg/g;在模拟汗液析出过程中,温度升高有利于再生聚酯纤维中锑的析出,而时间延长以及pH值减小会使锑的析出增加,在迁移时间达到120 min后锑析出量达到平衡,约为1.3μg/g。     

喷霜

喷霜又名喷出(blooming)，是橡胶加工过程中常见的质量问题，它是指未硫化胶或硫化胶中所含的配合剂迁移到表面并析出的现象。有时，这种喷出物呈霜状结晶物，故习惯上称“喷霜”。较多见的喷霜物为硫，因为硫黄是通用橡胶中应用最广泛的硫化剂，且在橡胶中的溶     

焦化厂土壤中PAHs的累积、垂向分布特征及来源分析

引言多环芳烃(polycyclic aromatic hydrocarbons,PAHs)在环境中普遍存在,由于具有强烈的诱变、致癌和致畸作用而受到越来越多的关注。以煤为主要原料的焦化行业,是环境中人类活动产生PAHs的主要来源之一,其各个生产车间内化石燃料的不完全燃烧及焦油、煤气等化工产品的加工过程都可能导致PAHs的排放。土壤是PAHs累积和迁移的重要介质,环境中的PAHs可由大气     

负载型防老剂研究进展

防老剂用于改善聚合物在加工过程中的热氧化稳定性并延长聚合物材料的使用寿命。传统的小分子防老剂易迁移挥发,这不仅会降低防老化效果且会造成环境污染问题。将防老剂固定在载体上制备负载型防老剂是减少防老剂迁移性问题的方法之一。综述了负载型防老剂的设计,合成和应用研究。这些负载型防老剂具有良好的抗迁移性、耐挥发性、抗萃取性,在长期使用过程中表现出良好的耐老化效果,因此在实际应用中具有很大的潜力,可以有效提高聚合物材料的稳定性。     

Wheat gluten nanocomposite films as food‐contact materials: Migration tests and impact of a novel food stabilization technology (high pressure)

The aptitude of a novel biodegradable material [wheat gluten/montmorillonite (MMT)] to be used as a food‐contact material was assessed with a focus on mass transfer from the film into foodstuff (migration). Special attention was paid to the impact of high‐pressure treatments and subsequent storage. Several aspects were treated: the migration of a model molecule (Uvitex OB), MMT migration, protein migration, and overall migration. The results showed that overall migration and protein migration were high; on the contrary, MMT and Uvitex OB migration was low or not detectable. No difference was found between the high‐pressure‐treated samples and the control, except for the migration of MMT. Two solid simulants (agar gel and Tenax) were also tested to emphasize the need of new migration tests adapted to water‐sensitive materials. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Cell Adhesion and Its Endocytic Regulation in Cell Migration during Neural Development and Cancer Metastasis

Cell migration is a crucial event for tissue organization during development, and its dysregulation leads to several diseases, including cancer. Cells exhibit various types of migration, such as single mesenchymal or amoeboid migration, collective migration and scaffold cell-dependent migration. The migration properties are partly dictated by cell adhesion and its endocytic regulation. While an epithelial-mesenchymal transition (EMT)-mediated mesenchymal cell migration requires the endocytic recycling of integrin-mediated adhesions after the disruption of cell-cell adhesions, an amoeboid migration is not dependent on any adhesions to extracellular matrix (ECM) or neighboring cells. In contrast, a collective migration is mediated by both cell-cell and cell-ECM adhesions, and a scaffold cell-dependent migration is regulated by the endocytosis and recycling of cell-cell adhesion molecules. Although some invasive carcinoma cells exhibit an EMT-mediated mesenchymal or amoeboid migration, other cancer cells are known to maintain cadherin-based cell-cell adhesions and epithelial morphology during metastasis. On the other hand, a scaffold cell-dependent migration is mainly utilized by migrating neurons in normal developing brains. This review will summarize the structures of cell adhesions, including adherens junctions and focal adhesions, and discuss the regulatory mechanisms for the dynamic behavior of cell adhesions by endocytic pathways in cell migration in physiological and pathological conditions, focusing particularly on neural development and cancer metastasis.     

一次性塑料饭盒中双酚A在食品模拟溶剂中的迁移

文章研究了一次性塑料饭盒中的双酚A在不同食品模拟溶剂条件下的迁移规律.实验采用高效液相色谱法对在不同食品模拟溶剂中迁移的双酚A进行了检测.结果表明,双酚A在不同食品模拟溶剂中的迁移量,主要受温度、溶剂极性及萃取方式的影响.随着水浴温度的升高,双酚A迁移量逐渐增加,但由于双酚A易挥发,温度过高时,溶出物中双酚A的量反而减小;相同温度时,在不同食品模拟溶剂中,溶剂极性越小,溶出物中双酚A的迁移量越高;溶剂相同时,不同萃取方式下的迁移量不同,实验表明：一次性塑料饭盒中的双酚A用微波萃取比水浴加热萃取时的迁移量明显增加.     

聚苯乙烯杯中苯乙烯在豆制品、粥类食品和醇类模拟物中的迁移对比

选取苯乙烯迁移量作为测试指标,对比了聚苯乙烯杯中残留苯乙烯在真实食品及醇类食品模拟物中的迁移量,分析确认适合这几类中国特色食品的模拟物。采用顶空?气相色谱法测定苯乙烯在3类真实食品、10 %乙醇（体积分数,下同）和20 %乙醇中的迁移量,采用高效液相色谱法测定苯乙烯在50 %乙醇和95 %乙醇中的迁移量。结果表明,豆类饮料中苯乙烯迁移量介于其在20 %乙醇和50 %乙醇中的迁移量之间;豆腐和粥中苯乙烯的迁移量接近10 %乙醇和20 %乙醇,均远低于50 %乙醇;根据食品接触材料及制品的食品模拟物适用性原则,应选择与食品迁移量接近或大于食品迁移量的模拟物,建议豆类饮料选择50 %乙醇作为模拟物,豆腐类食品和粥类食品选择20 %乙醇作为模拟物,相关结果可为食品安全国家标准的修订提供参考。     

Approximate migration coefficient of interfacial transition zone and the effect of aggregate content on the migration coefficient of mortar

In this study, the electrochemical technique is applied to accelerate chloride ion migration in mortar to estimate its transport properties. In order to investigate the effect of aggregate content on the chloride migration coefficient of mortar, specimens with different fine aggregate volume fractions were cast and tested. The chloride migration coefficient of mortar was determined experimentally as a function of the volume fraction of aggregate. The chloride migration coefficient of mortar is used to assess the dilution, tortuosity and interfacial transition zone (ITZ) effects of aggregate in the cement-based composites. A model modified from the Bruggeman theory for the migration coefficient of mortar is used, and the regression analysis is used to determine the approximate chloride migration coefficient of ITZ. Based on the experimental and regression analytical results, the approximate ITZ migration coefficient is 2.83, 1.76 and 1.55 times of the matrix migration coefficient for the ITZ with the thickness of 20, 40 and 50 μm, respectively.     

Stretch-Induced Tenomodulin Expression Promotes Tenocyte Migration via F-Actin and Chromatin Remodeling

The mechanosensitive gene tenomodulin (Tnmd) is implicated in tendon maturation and repair. However, the mechanism by which mechanical loading regulates Tnmd’s expression and its role in tenocyte migration is yet to be defined. Here, we show that Tnmd and migration were upregulated in uniaxial cyclic stress-stimulated tenocytes. The knockdown of Tnmd reduced cell migration in the presence and absence of mechanical loading, suggesting that Tnmd is involved in tenocyte migration. Moreover, the treatment of stress-stimulated tenocytes with the actin inhibitor latrunculin (Lat A), histone acetyltransferase inhibitor anacardic acid (ANA), or histone demethylases inhibitor GSK-J4 suppressed Tnmd expression and tenocyte migration. These results show that actin stress fiber formation and chromatin decondensation regulates Tnmd expression, which might then regulate tenocyte migration. Thus, this study proposes the involvement of the actin and chromatin mechanotransduction pathway in the regulation of Tnmd and reveals a novel role of Tnmd in tenocyte migration. The identification of Tnmd function in tenocyte migration provides insight into the molecular mechanisms involved in Tnmd-mediated tendon repair.     

Modification of doping front migration in electrochemical devices and application to organic electronics

We demonstrate several methods of modifying the doping front migration process in multilayer structures, enabling control of migration velocity and switching between different migration mechanisms. Sharp jumps in migration velocity may be induced using a delamination effect. The influence of migration layer thickness and composition is examined. Migration velocity may also be influenced by exposing the system to a defined relative humidity or by varying the concentration of a hygroscopic salt in the migration layer. The migration mechanisms can be explained in terms of diffusion, capillary transport, and delamination. By tailoring the migration process a variety of polymer electronic structures such as pseudo transistors (enhancement and depletion type) and electrical switches (ON–OFF and OFF–ON) may be fabricated. Further examinations about the doping front width are given and the phenomenon of a double front is described.     

二茂铁基超支化聚(胺)酯的抗迁移性研究

将二茂铁基超支化聚(胺)酯(HPAE-Fc)添加到端羟基聚丁二烯(HTPB)中老化,通过紫外分光光度计测定了HTPB基体中二茂铁基团含量,并计算了HPAE-Fc迁移率,与二茂铁、叔丁基二茂铁的迁移率进行了对比.研究结果表明:HPAE-Fc的迁移率远低于二茂铁、叔丁基二茂铁,迁移率随着相对分子质量的增大而减小,迁移率由高到低的顺序为二茂铁、叔丁基二茂铁、HPAE-Fc;各物质的迁移率随时间延长或温度提高而增加.实验结果表明:与二茂铁和叔丁基二茂铁相比,HPAE-Fc在HTPB中具有较强的抗迁移性能.HPAE-Fc在HTPB中抗迁移性的机理为高的相对分子质量、化学组成与结构、较强的分子间作用力、良好的相容性和与HTPB形成氢键等因素共同作用的结果.     

Approximate migration coefficient of percolated interfacial transition zone by using the accelerated chloride migration test

In this study, the electrochemical technique is applied to accelerate chloride ion migration in cement-based material to estimate its migration coefficient. In order to investigate the chloride migration coefficient of percolated interfacial transition zone (ITZ) on the chloride migration coefficient of specimen, specimens with cylindrical aggregates of the same height as the specimen were cast and tested. In this study, the volume fraction of aggregate is constant and the varied lateral surface area of the aggregate cylinder was obtained by using different diameters and number of aggregate. The chloride migration coefficient of cement-based material was determined experimentally as a function of the lateral surface area of aggregate. A model obtained for the migration coefficient of cement-based material and the regression analysis are used to determine the approximate chloride migration coefficient of the percolated ITZ. Based on the experimental and regression analytical results, the approximate percolated ITZ migration coefficient is 40.6, 35.5, and 37.8 times of the altered migration coefficient of matrix mortar for the water/cement (w/c) ratio of 0.35, 0.45, and 0.55, respectively.     

软质PVC中增塑剂在不同溶媒中的迁移行为

研究软质PVC交联前后,增塑剂对苯二甲酸二辛酯在蒸馏水、3%乙酸、10%乙醇和橄榄油浸泡溶媒中的迁移行为。结果表明:增塑剂在蒸馏水和乙醇浸泡溶媒中,前24 h缓慢上升后趋于平缓;在乙酸浸泡环境中,交联改性延迟了增塑剂迁移出来的时间;在橄榄油浸泡溶媒中,前24 h迅速上升后也逐渐趋于平缓,交联改性对增塑剂迁移有一定的抑制作用,凝胶含量越大,迁移率越小。无论PVC交联与否,增塑剂在不同溶媒中的迁移率大小顺序均为:橄榄油>10%乙醇>蒸馏水>3%乙酸。