Bounded Positive Solutions of Schrödinger Equations in Two-Dimensional Exterior Domains

We prove under quite general assumptions the existence of a bounded positive solution to the semilinear Schrödinger equation in a two-dimensional exterior domain.     

7-氮杂-3,6-二氧杂-二环[3.3.0]辛-2-酮类化合物合成的新方法

5-甲氧基-2-（5H）-呋喃酮与氮酸硅烷基酯通过1，3-偶极环加成反应可以为7-氮杂-4-甲氧基-3，6-二氧杂-二环[3.3.0]辛-2-酮类化合物提供新的合成途径。通过元素分析、IR、^1HNMR、^13CNMR、MS等波谱分析进行了结构表征。     

Direct melting polycondensation and characterization of poly(ɛ-caprolactone-co-lactic acid)

A kind of biodegradable material, poly(ɛ-caprolactone-co-lactic acid) [P(CL-co-LA)] was synthesized via the direct melting polycondensation of lactic acid (LA) and ɛ-caprolactone (CL). The influences of the polycondensation time, and the catalyst type on the intrinsic viscosity of P(CL-co-LA) were also investigated. The results indicate that P(CL-co-dl-LA), with an intrinsic viscosity of 0.4733 dL/g, can be prepared by direct melting polycondensation with the molar ratio LA/CL = 3:7 at 180°C and 70 Pa for 12 h, using 0.5% (mass fraction) of SnCl₂ as the catalyst. Compared with lactide ring-opening polycondensation (ROP), the direct melting polycondensation of LA and CL is more practicable and simple. Translated from Journal of South China University of Technology, 2006, 34(7): 7–11 (in Chinese)     

水解聚合铝溶液中Al30形态的研究

水解聚合铝形态一直是分析、催化、土壤、地球化学、新材料、环境科学和生物毒理学等众多领域研究的前沿和热点。Keggin 结构的Al₃₀ 形态是迄今为止发现的电荷最高的水解铝聚合阳离子,具有独特的分子结构和纳米分子尺寸,它对催化化学、新型功能材料、高效絮凝剂的开发以及铝的水解聚合转化规律研究具有重要意义。本文主要论述了Al₃₀形态的形成、形态分析方法、结构模型以及形成机理等方面的最新研究进展,并对水解聚合铝溶液的研究发展趋势进行了展望。     

Novel expanded porphyrinoids with multiple-inner-ring-fusion and/or tunable aromaticity

Novel expanded porphyrinoids with advanced structure features have a wide range of benefits (such as multi-metal coordination and facile tunable aromaticity) not offered by their normal porphyrin analogues. Considering research efforts have been devoted to address their limited synthetic accessibility issue. This review highlights some of these recent synthetic progresses towards these novel expanded porphyrinoids.     

Optimization of a MALDI TOF-TOF mass spectrometer for intact protein analysis

A MALDI TOF-TOF instrument was optimized and evaluated for intact protein analysis by tandem mass spectrometry. Ion source voltages and delay times were adjusted to affect an up to a 10-fold improvement in fragment ion yield compared to data obtained using default settings employed in peptide analysis. For large peptides (3-4.5 kDa), up to 90% of all possible b- and y-fragment ions were observed, which provides sufficient information for de novo sequencing and unambiguous protein identification. Product ion signals associated with preferential cleavages C-terminal to aspartic acid and glutamic acid residues and N-terminal to proline residues became dominant with increased protein molecular weight. Matrix effects were also evaluated and, among the eight matrices examined, alpha-cyano-4-hydroxycinnamic acid (CHCA) was found to produce the best intact protein tandem mass spectra for proteins up to 12 kDa. Optimized performance yielded detection limits of 50-125 fmol for proteins of 4 and 12 kDa, respectively. This improved performance has yielded an instrument with potential to be a useful tool in proteomic investigations via analysis of intact proteins.     

用手性高效液相色谱对β—羟基酯化合物进行对映体分离

本文利用手性ＯＤ柱在高效液相色谱上对光活性β－羟基酯类化合物进行了对映体分离，达到了较好的分离效果，并通过讨论手性ＯＤ涂附物的结构与该类化合物的作用方式，解释了不同的该类化合物的色谱分离效果。     

大孔吸附树脂对邻甲酚的吸附行为研究

研究了大孔吸附树脂NDA—909吸附水溶液中邻甲酚的热力学特征，并与Amberlite XAD—4树脂进行了比较．通过吸附动力学实验，初步探讨了初始温度对吸附过程的影响。结果表明，NDA—909对邻甲酚的吸附符合Freundlich经验公式，表现为放热的物理吸附过程．此外吸附速率受颗粒内扩散和其它类型扩散的共同控制。     

苯并噁嗪中间体/蛭石插层纳米复合物热固化行为的研究

通过对双酚A型苯并嗪中间体 (BOZ A) 蛭石插层纳米复合物固化过程的分析表明长链烷基铵阳离子对BOZ A的热开环聚合反应没有表现出催化作用 ,也不影响纳米复合物的结构形态 .不同蛭石含量的插层纳米复合物 ,在形成不同纳米分散状态的纳米复合物的过程中 ,蛭石晶片对BOZ A的热开环聚合具有明显不同的阻碍作用 ,蛭石含量为 3%的插层纳米复合物 16 0℃的凝胶化时间较纯树脂延长约 7min ,活化能升高约8kJ mol,固化反应热焓降低约 14J g ,使得固化物的固化程度较纯树脂降低约 7%～ 10 % ,阻碍作用最大 ,其它含量的次之     

Cover Picture: Highly Regioselective Sequential 1,1‐Dihydrosilylation of Terminal Aliphatic Alkynes with Primary Silanes (Chin. J. Chem. 5/2019)

The cover picture shows that sequential 1,1‐dihydrosilylation of terminal aliphatic alkynes with primary silanes enabled by one earth‐abundant cobalt catalyst has been developed. This protocol is operationally simple using readily available aliphatic alkynes, including simple acetylene and complex drug derivative, for efficient access to valuable gem‐bis(dihydrosilyl)alkanes in highly regioselective and atom‐economic manners. Corresponding asymmetric transformations are achieved with excellent enantioselectivities. More details are discussed in the article by Lu et al. on page 457–461.