An In situ Study on the Orderly Crystal Growth of Pluronic F127 Block Copolymer Blended with and without Ionic Liquid during Isothermal Crystallization

Isothermal crystallization behavior of Pluronic F127 blended with and without an ionic liquid (IL) was investigated by in situ polarized optical microscopy (POM) and Fourier transform infrared spectroscopy (FTIR). For the pure F127, the POM and FTIR results showed that the spherulite size and crystallinity of F127 increased with the melting temperature increasing to 60, 80, and 135°C. This could be explained by the flexibility of the polymer chain at high melting temperatures. For the F127 blended with IL, the POM results showed that the morphology of F127 evolved from spherulite to dendritic segregation and fibrous crystal with the increasing IL content. FTIR results indicated that hydrogen bonds were formed between F127 and IL, and the intensity of the hydrogen bonds became strengthened gradually with increasing IL content. The effect of hydrogen bonds on the morphology evolution of F127/IL is discussed.     

Non-cancelable betti numbers and type vectors

We examine ak-configuration ${\mathbb{X}}$ in ?² or ?³ whose minimal free resolution has a non-cancelable Betti number in the last free module. We also find partial answers to the question: which Artinian O-sequences are level or not?     

电子束产生大尺度等离子体过程的数值模拟研究

建立了一个四组分一维混合模型，对电子束注入大气产生大尺度等离子体的过程进行了数值模拟.结果表明了能量为140keV、流强为50mA/cm²的注入电子束，可以产生线度为0.5m，密度为10¹²cm^-3量级的大气环境下等离子体.电子束所伴随的空间电荷效应由于等离子体的产生会很快消失，不影响后续的等离子体产生过程.电子束注入流强主要影响产生等离子体的密度，而电子束能量则同时影响其空间线度和密度. 关键词： 电子束 碰撞 电离     

用手性配体改性铝锂试剂对芳香酮的还原

用手性一元酮作辅助配体,与１,２,５,６－二丙酮甘ｉＡｌｈ５对芳香酮进行对映选择 的,得到光学活性产物８个。通过与α－乙酰氧基－Ｌ－丙酰氯生成非对映异构体酯,经气相色谱分析,芳酮挑学产率为２３．３￣７１．２％。初步探讨了配体之间对称性匹配的情况。     

V3+:YAG晶体的生长、色心与光谱性能研究

采用石墨电阻加热的温梯法生长了V:YAG晶体,晶体的不同部位呈现两种不同的颜色:浅绿色和黄褐色.通过对比分析不同颜色V:YAG晶体的室温吸收光谱,推断出石墨发热体高温下扩散出来的C可以起到还原作用,提高晶体中V3+tetra离子的浓度,同时诱导了F心的形成.在1300℃下,对不同颜色的V:YAG晶体进行真空退火处理,发现处于八面体格位中的V3+离子在热激发作用下与近邻的四面体格位Al3+离子存在置换反应,由此产生一定浓度的四面体格位V3+离子.同时,F心在退火过程中被完全消除,释放出来的自由电子被高价态的V离子俘获,可以进一步提高晶体中四面体格位V3+离子的浓度.     

Sensitive immunoassay for the β-agonist ractopamine based on glassy carbon electrode modified with gold nanoparticles and multi-walled carbon nanotubes in a film of poly-arginine

We are presenting an electrochemical immunosensor for the determination of the β-agonist and food additive ractopamine. A glassy carbon electrode (GCE) was modified with gold nanoparticles and a film of a composite made from poly(arginine) and multi-walled carbon nanotubes. Antibody against ractopamine was immobilized on the surface of the modified GCE which then was blocked with bovine serum albumin. The assembly of the immunosensor was followed by electrochemical impedance spectroscopy. Results demonstrated that the semicircle diameter increases, indicating that the film formed on the surface hinders electron transfer due to formation of the antibody-antigen complex on the modified electrode. Under optimal conditions, the peak current obtained by differential pulse voltammetry decreases linearly with increasing ractopamine concentrations in the 0.1 nmol•L⁻¹ to 1 μmol•L⁻¹ concentration range. The lower detection limit is 0.1 nmol•L⁻¹. The sensor displays good stability and reproducibility. The method was applied to the analysis of spiked swine feed samples and gave satisfactory results.

Immunoassay for ractopamine based on glassy carbon electrode modified with gold nanoparticles and a film of a composite made from poly (arginine) and multi-walled carbon nanotubes was proposed. Under optimal conditions, the peak currents obtained by differential pulse voltammetry decreases linearly with increasing ractopamine concentrations in the 0.1 nmol•L⁻¹ to 1 μmol•L⁻¹ concentration range. The detection limit is 0.1 nmol•L⁻¹.

     

FeS2多晶薄膜电子结构的实验研究

用磁控溅射方法制各纯Fe薄膜，并硫化合成FeS₂. 采用同步辐射X射线近边吸收谱与X射线光电子能谱研究了薄膜的电子结构. 结果表明，合成的FeS₂薄膜，在费米能级附近，有较强的Fe 3d态密度存在，同时，在价带谱中2—10eV处有强度较大的S 3p态密度存在；Fe的3d轨道在八面体配位场作用下分别为t_2g和e_g轨道，实验中由Fe的吸收谱计算得到两分裂能级之差为2.1eV;实验测得FeS₂价带结构中导带宽度约为2.4eV，导带上方仍存在第二能隙，其宽度约为2.8eV. 关键词： 磁控溅射 二硫化铁 X射线吸收近边结构 电子结构     

液体聚了二烯原位涂层研究”──Ⅱ．电活性铝离子的形成及其对PBA的凝聚作用

采用电量法和失重法，测定了裸洁Ａｌ电极在不同浓度、温度和ＰＨ值的聚丁二烯酸（ＰＢＡ）溶液中阳极溶解速度，确定了电活性Ａｌ（Ⅲ）离子的最佳形成条件及其对ＰＢＡ的凝聚作用规律．结果表明，在６０℃温度，ｐＨ＝３．０的０．６ｍｏｌ·Ｌ－１柠檬酸＋１．０ｇ·Ｌ－１ＰＢＡ溶液中产生的电活性铝离子对水溶性不饱和高分子低聚物的凝聚作用最强．简单讨论了这一电凝聚作用的机理．     

Structural tuning of coordination polymers by 4-connecting metal node and secondary building process

Due to variation in ligand's conformation, metal node's connecting geometry, and secondary building process by anions, bat-like, dumbell-like, diamondoid, or pillar-layer topologies are achieved.     

含吡唑环的双杂环化合物的合成及其生物活性

以4-硝基-5-吡唑甲酰肼为起始物,合成了一系列含硝基的5-吡唑基-1,3,4-噁二唑类、5-吡唑基-1,3,4-噻二唑类和5-吡唑基-1,3,4-三唑类的化合物.初步生测结果表明:部分化合物有较好的杀菌和内吸活性.