共查询到19条相似文献,搜索用时 140 毫秒
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研究了5种不同碳酸钙含量的PLA/PBAT/CaCO3复合膜中的钙在40 ℃和70 ℃下向3%乙酸食品模拟物的迁移及向3种食品模拟物(3%乙酸、10%乙醇、95%乙醇)的总迁移,探究了复合膜中碳酸钙含量与总迁移的关系,并研究了紫外老化处理对迁移的影响。结果表明,5种复合膜向3%乙酸中的总迁移量均超过总迁移限值(OML),且总迁移主要受复合膜中碳酸钙含量的影响,钙浓度与总迁移量呈线性关系。同时,随着复合膜中碳酸钙含量的增加,钙的迁移量增加,且不同碳酸钙含量的复合膜均在短时间内达到迁移平衡(40 ℃,4 h)。将复合膜紫外老化处理较长时间(24 h以上)会导致钙的迁移量减少,可能的原因是紫外照射引起聚己二酸/对苯二甲酸丁二酯(PBAT)的交联反应,从而抑制了钙的迁移。此类生物降解复合膜作为食品接触材料的安全性值得进一步关注和研究。 相似文献
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测定了成矿过程不同阶段形成的包裹体温度、压力及成分,结合实验地球化学和热力学方法,研究了石棉碲矿床成矿热液在成矿过程中的物理化学条件、迁移形式及碲沉淀富集的地球化学机理。结果表明,碲在热液中主要以H2Te、HTe-、Te22-、Te2-的形式迁移,并在Eh升高,pH、fo2、fs2和fTe2降低的情况下富集。 相似文献
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用麦克斯韦(Maxwell)能量分布和能量均分原理推导溶质迁移速度方程, 研究了N2- GDX-101气固色谱体系中5种烷烃的迁移速度、迁移活化能和迁移中溶质分子热运动的作用. 得到的迁移活化能可以很好地解释溶质的迁移速度. 研究结果表明, 溶质分子的转动\, 振动能量显著地影响迁移活化能. 用统计热力学的估算验证的计算结果表明, 迁移活化能明显小于脱附焓. 溶质迁移时可能远未达到解吸脱附的状态. 流动相驱动的溶质迁移可能主要为吸附状态下的滑移. 相似文献
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本文在Pettit机理基础上,提出Reppe醛化反应的催化环模型。利用改进的CNDO/2方法对环中主要络合物的结构、性能及氢迁移和乙基迁移等动态过程进行了详细的研究。H_2Fe(CO)_4作为Reppe合成的真实催化剂,反映在体系总能量、键级演变及前线轨道的结构变化等方面都较合理。 相似文献
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溶质迁移研究已成为水文地质等领域的一个重要研究课题。综述了溶质迁移研究进展,重点介绍了溶质迁移在地下水污染与防治、土壤盐碱化防治、海水入侵和咸水入侵防治等方面的研究现状,并指出应进一步研究的问题。 相似文献
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考查了抗战时期中央研究院化学所的内迁经过以及在大后方恢复重建、开展科学研究的艰难历程,并对化学所战时科研的特点及学术贡献等相关问题进行详细探讨。 相似文献
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《中国化学快报》2022,33(7):3405-3412
The radionuclide (RN) migration study is not only helpful to understand environmental behavior of RNs, but also can establish the basis for the safety assessment of geological disposal of high-level radioactive waste (HLW). In the context of China's HLW disposal, this review briefly summaries the progress of China's RN migration studies over the past decade regarding three aspects, RN sorption, RN transport and radioactive colloid. Domestic studies from other disciplines (such as geology and environmental science) are also included in this review because they can provide references for the RN migration study. Overall, China has achieved clear progress in RN migration study over the past decade, although large-scaled field experiments are lacked and a gap still exists comparing with the international advanced level. Finally, several suggestions are proposed for future RN migration research in China. 相似文献
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大小选择的金属支撑团簇研究进展* 总被引:3,自引:0,他引:3
从团簇的产生, 团簇的沉积过程, 团簇在固体表面的迁移和团簇的反应活性等方面对大小选择的金属支撑团簇的研究现状进行了综述, 并展望了这一领域的研究趋势。 相似文献
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聚酯类食品包装材料中二氧化钛在食品模拟物中的迁移规律 总被引:1,自引:0,他引:1
采用电感耦合等离子体质谱法(ICP–MS),在不同的模拟迁移条件(模拟物、盛放温度、接触时间、乙酸浓度、使用次数等)下,研究聚酯类食品包装材料中二氧化钛在6种食品模拟物(水、4%乙酸、10%乙醇、65%乙醇、正己烷和异辛烷)中的迁移规律。结果显示:食品模拟物的属性对迁移行为有显著影响,迁移量随温度的升高及时间的延长而增加,食品的酸性越强,二氧化钛的迁移量越大。因此需适量控制聚酯类食品包装材料的反复使用次数、盛放食品时的温度和时间以降低二氧化钛迁出风险。 相似文献
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In order to further explore the profile control and displacement mechanism of continuous and discontinuous phase flooding agent, the concentration distribution mathematical model of microsphere dispersion system in different branch channels is established, and its particle phase separation is simulated by using microfluidic technology. On this basis, in order to research the migration and plugging characteristics of microspheres, the visualization experiments on micro oil displacement mechanism of polymer solution and microspheres are carried out. And the experiment on the injection, migration, and plugging performance of microspheres in the multi-point core is performed. Results indicate that microspheres are in the axis of the channel due to the effect of fluid shear stress, and preferentially enter the large channel with low resistance and high flow velocity, which results in no particle or few particles in the small aperture and low flow velocity channel. The microspheres have better migration and retention capacity in the core and their migration shows the characteristic of “fluctuating pressure change”. Compared with polymer solution, the alleviation of “entry profile inversion” and the better migration and plugging performance of microsphere dispersion system can realize deep fluid diversion and expand sweep volume. 相似文献
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Balazadeh Navid Shafee Ahmad Tlili Iskander 《Journal of Thermal Analysis and Calorimetry》2021,144(3):1041-1050
Journal of Thermal Analysis and Calorimetry - In current research, MAPLE software was utilized to scrutinize the heat transfer of copper–H2O nanomaterial migration over a sheet. Entropy... 相似文献
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Dr. Jun Nakanishi 《Chemical record (New York, N.Y.)》2017,17(6):611-621
Photoactivatable substrates, which show changes in surface cell adhesiveness in response to photoirradiation, are promising platforms for cell manipulation with high spatiotemporal resolution. In addition to having applications in cell and tissue engineering, these materials are unique tools for basic biological sciences research, and they complement conventional genetic engineering technologies. One of the most useful applications is in the study of cell migration, which occurs in various physiological and pathological processes. In this personal account, I provide a brief overview of the development of photoactivatable substrates and their applications, highlighting in particular the contributions of our research group to collective cell migration studies. This material‐based approach is useful for dissecting the molecular biological and mechanobiological aspects of the regulatory mechanisms in the cellular social activities. 相似文献