Diffusion mechanisms in the Fe_3Si alloys

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胶束电动力学毛细管色谱中峰的定性方法

从理论上探讨了在胶束电动力学毛细管色谱中采用迁移时间来定性的不足，提出将相对有效淌度用于该体系下尿中核苷组分的定性。结果表明：使用相对有效淌度作定性指标，其平均相对标准偏差为1．54％，明显优于同迁移时间进行定性所得的平均相对标准偏差7．9％。提出用识别系数评价定性的可靠性。当使用相对有效淌度作定性指标时，75％以上的分析物都达到了可靠识别。识别可靠性与采用迁移时间相比最高可提高16倍。     

交联PPE固态π-π堆积效应的研究

本文合成了数种乙烯基封端及结构规整无侧基的PPE齐聚物, 通过端乙烯基的交联反应, 制备了柔性端基交联的三维PPE交联网络. 通过FTIR, PL, WXRD分析, 研究了乙烯基交联程度和热处理条件等对交联PPE π-π堆积效应的影响, 成功地制备了固态无π-π堆积和单色性好的紫/蓝光发光材料.     

A fluorescence labeling approach to assess the deterioration state of aged papers

Deterioration of historical papers is caused by several processes, such as acid hydrolysis or autoxidation due to the presence of metal ions contained in inks or pigments. Both processes can be studied by fluorescence labeling of carbonyl and carboxyl groups in combination with GPC-MALLS. This technique allows to determine not only the extent of hydrolysis, but also the concentration of oxidized functionalities within very low sample amounts.The thermally induced aging of rag papers with lines of copper pigment has been investigated, simulating green or blue copper pigments in historic wall papers. The cellulose parts with pigment coverage and adjacent pigment-free regions were analyzed separately and compared to paper parts not affected by metal ions. The cellulose underneath and close to the applied pigment strokes was severely affected. Although there was no difference in the molecular weight distribution, distinct differences in the carbonyl and carboxyl content were observed. Copper ion migration is suggested to be one possible explanation for this observation as a strong correlation between distribution of copper ions and carbonyl groups was found. For the first time, a detailed examination of cellulose damage in spatial proximity to metal-containing pigment lines is thus presented.     

Preparation and Structure of [(η5‐C5H5)Fe(CO){C(O)Ph}2]2Li2(2,2′‐Bipyridine): A Sequential Treatment of Nucleophile Followed by Lewis Base

Unable to elaborate (η⁵‐C₅H₅)Fe(CO)₂C(O)Ph by the nucleophile/electrophile sequences, the treatment of nucleophile PhLi followed by Lewis base 2,2′‐bipyridine instead leads to the meaningful isolation of [(η⁵‐C₅H₅)Fe(CO) {C(O)Ph}₂]₂Li₂(2,2′‐bipyridine).     

FTIR investigation of the specific migration of additives from rigid poly(vinyl chloride)

Commercial sunflower oil was epoxidized and used as organic costabiliser for rigid poly (vinyl chloride) (PVC) containing zinc and calcium stearates as primary stabilisers and stearic acid as lubricant. For applications in the packaging of foodstuffs, migration testing must be realised. For that purpose, two food simulants were used (sunflower oil and 15% (v/v) aqueous ethanol). The test conditions were 12 days at 40 °C. Circular samples of rigid PVC were immersed in a well known volume of food simulant. A circular sample and 10 ml of food simulant were taken off every day to be analysed. The specific migrations of the additives were investigated by using Fourier transform infrared spectroscopy.The direct analysis of the food simulants was difficult because overlapping of the bands of the additives. However, the analysis of PVC films obtained by dissolution of the circular samples in tetrahydrofuran and evaporation of the solvent was more conclusive. The specific migrations of the metal carboxylates and epoxidized sunflower oil were evidenced.     

Analytical protocol to study the food safety of (multiple-)recycled high-density polyethylene (HDPE) and polypropylene (PP) crates: Influence of recycling on the migration and formation of degradation products

An analytical protocol was set up and successfully applied to study the food safety of recycled HDPE and PP crates. A worst-case scenario was applied that focused not only on overall migration and specific migration of accepted starting materials but also on migratable degradation products of polymers and additives that may be formed during mechanical recycling.The analytical protocol was set up to cover a wide variety of possible migrants. Identification and semi-quantification were possible for almost all migrants that increased significantly with increasing mechanical recycling steps for both the HDPE and PP crates.It was concluded that the analytical protocol was suitable to study the influence of (multiple) recycling on the food safety of plastic materials. The protocol can be applied to other plastic food contact materials and provides valuable information on the food safety of the recycling process and the resulting recycled food contact materials in addition to challenge testing.     

带边缘驱动的214单元单压电变形镜仿真与实验

为了提高用于天文自适应光学系统的单压电变形镜的校正能力,提出了一种直径为75 mm且包含214个单元的带边缘驱动的单压电变形镜,单压电变形镜的边缘由数个压电堆栈执行器支撑.首先,通过有限元方法对变形镜进行仿真建模,分析比较三点、六点能动支撑对变形镜性能的影响.之后制备了三点、六点边缘驱动的变形镜样机.最后,利用波前传感器测试了边缘执行器对低阶像差的校正能力.实验结果表明:在0~100 V电压下,三点能动支撑与六点能动支撑变形镜均可重构大于12μm的倾斜像差,对应的归一化残余误差小于0.06,六点致动对像散和三叶草像差也具有较好的校正能力,证明边缘执行器可提高单压电变形镜的校正能力.     

miR-99a对乳腺癌细胞侵袭和迁移的负向调控机制研究

目的探讨miR-99a对乳腺癌细胞侵袭及迁移的影响,并初步分析其影响乳腺癌细胞侵袭及迁移的可能分子机制。方法利用荧光实时定量PCR检测乳腺癌细胞系MDA-MB-231和MCF-7中miR-99a的表达。运用脂质体介导的转染方法分别将miR-99a模拟物（miR-99amimics）、miR-99a抑制物（miR-99ainhibitors）以及相应对照miRNA转染MDA-MB-231和MCF-7细胞,通过Transwell侵袭实验检测细胞的侵袭力;采用Transwell迁移实验及划痕实验检测细胞的迁移能力;利用生物信息学方法预测miR-99a的靶基因,并对靶基因进行验证。结果（1）高转移潜能的MDA-MB-231细胞中miR-99a表达明显低于低转移潜能的MCF-7细胞,划痕实验中转染miR-99amimics的与转染controlmimics的MDA-MB-231细胞比较迁移能力显著减弱（P＜0.05）,而MCF-7细胞转染miR-99ainhibitors后迁移能力明显增强（P＜0.01）。（2）Transwell的侵袭及迁移实验显示,转染miR-99amimics后MDA-MB-231细胞的侵袭和迁移能力明显减弱（P＜0.01）;MCF-7细胞转染miR-99ainhibitors后迁移能力增强（P＜0.01）,而侵袭能力基本不变（P＞0.05）。（3）生物信息学方法预测微管相关蛋白（MTMR3）是miR-99a的靶点,实时定量PCR和3′UTR荧光素酶报告基因实验验证了该靶点。（4）干扰了MTMR3后MDA-MB-231细胞的迁移和侵袭能力明显减弱。结论（1）miR-99a对乳腺癌细胞的侵袭及迁移发挥负向调控作用。（2）miR-99a可能通过靶向于MTMR3发挥其对乳腺癌细胞迁移和侵袭的调控作用。     

Alleviating Side Reactions on Zn Anodes for Aqueous Batteries by a Cell Membrane Derived Phosphorylcholine Zwitterionic Protective Layer

Aqueous zinc (Zn) ion batteries are attractive for next generation batteries with high safety, yet their applications are still hindered by the uncontrollable dendrite formation and side reactions on Zn anode. Here, a polyzwitterion protective layer (PZIL) was engineered by polymerizing 2-methacryloyloxyethyl phosphorylcholine (MPC) in carboxymethyl chitosan (CMCS), which renders the following merits: the choline groups of MPC can preferentially adsorb onto Zn metal to avoid side reactions; the charged phosphate groups chelate with Zn²⁺ to regulate the solvation structure, further improving side reaction inhibition; the Hofmeister effect between ZnSO₄ and CMCS can enhance the interfacial contact during electrochemical characterization. Consequently, the symmetrical Zn battery with PZIL can keep stable for more than 1000 hours under the ultra-high current density of 40 mA cm⁻². The PZIL confers the Zn/MnO₂ full battery and Zn/active carbon (AC) capacitor with stable cycling performance under high current density.