An $L^{\infty}$ Second Order Cartesian Method for 3D Anisotropic Interface Problems

A second order accurate method in the infinity norm is proposed for general three dimensional anisotropic elliptic interface problems in which the solution and its derivatives, the coefficients, and source terms all can have finite jumps across one or several arbitrary smooth interfaces. The method is based on the 2D finite element-finite difference (FE-FD) method but with substantial differences in method derivation, implementation, and convergence analysis. One of challenges is to derive 3D interface relations since there is no invariance anymore under coordinate system transforms for the partial differential equations and the jump conditions. A finite element discretization whose coefficient matrix is a symmetric semi-positive definite is used away from the interface; and the maximum preserving finite difference discretization whose coefficient matrix part is an M-matrix is constructed at irregular elements where the interface cuts through. We aim to get a sharp interface method that can have second order accuracy in the point-wise norm. We show the convergence analysis by splitting errors into several parts. Nontrivial numerical examples are presented to confirm the convergence analysis.     

市场化改革背景下养老机构服务供给博弈研究

考虑政府补贴、市场化程度、养老机构服务成本、老年人偏好等因素,构建了完全国有化、公私并存的半市场化和完全市场化三种情形下公办和民办养老机构之间的两阶段博弈模型,比较分析了市场化程度对养老机构服务价格制定和服务水平选择的影响,实证讨论了各参数变化对养老机构收益及社会福利的影响。研究表明:完全市场化机制会降低养老机构服务质量,完全国有化机制会陷入社会福利陷阱,探索公私并存的最佳市场化水平才能更好地提高社会福利;适度推进市场化改革,提高养老机构服务水平,降低民办养老机构服务成本,适度提高对民办养老机构的补贴,将有效缓解公办和民办养老机构的不公平竞争;提高老年人支付能力,推进养老机构供给侧结构性改革,将保障机构养老服务的有效供给,促进养老服务业的健康有序发展。     

高亮度高效率蓝色聚合物发光二极管

蓝色聚合物发光二极管是人们关注的课题,前不久,我们报道[1]了利用ITO/PVCz/BBOT/Mg·Ag结构达到亮度1700cd/m2,量子效率0.2%的蓝色器件.在本文中我们报道以掺杂perylene(PRL)和triphenylamine(TPA)的poly(N-vinylcar-bazole)(PVCz)为空穴传输层,以PBD为空穴锁住层,Alq为电子注入层的器件,其亮度达6100cd/m2,量子效率达0.7500,流明效率0.451m/W的蓝色发光器件.就我们所知,这个亮度是蓝光中最高的亮度.     

用L-脯氨酸衍生物作为手性流动相添加剂拆分对映异构体

用自制的N-十二酰基-L-脯氨酸和N-十二酰基-L-脯氨酸-3，5-二甲基苯胺两种L-脯氨酸衍生物作手性流动相添加剂，在氨丙基硅烷化硅胶柱上，用正己烷／异丙醇作流动相，对多种手性化合物进行了高效液相色谱拆分。实验结果表明：用N-十二酰基-L-脯氨酸作添加剂拆分的12种手性化合物，有8种手性化合物能得到拆分，具有较好的手性选择性。虽然用N-十二酰基-L-脯氨酸-3，5-二甲基苯胺作添加剂，手性选择性也较好，但由于含有苯环，紫外吸收增强，基线波动严重。     

冠醚配合物的研究XV.若干席夫碱及仲胺型双冠醚和碱金属离子的配位反应

本文运用微量电导滴定及计算机拟合技术，研究了若干席夫碱及仲胺型双冠醚和碱金属离子的配位反应，测定了配合物的组成及稳定常数，并对实验结果进行了讨论。     

基地建设经验交流

南京大学化学化工学院于1991年被国家教委批准为首批国家基础科学研究和教学人才培养基地."基地方案的制定和实施"于1997年获国家教委优秀教学成果二等奖,并于1998年在国家自然科学基金委组织的中期评估中获得优秀基地的称号,1999年又以优异成绩顺利通过了教育部组织的基地挂牌验收.     

锆基纤维素手性固定相直接拆分萘普生衍生物

萘普生是一种消炎镇痛药 ,其 S对映体的抗炎作用是 R构型的 2 8倍 ,萘普生及其衍生物的拆分具有重要意义 .手性固定相 HPLC直接拆分 [1～ 4 ] 是最简便的分析方法 .氧化锆是近年来备受关注的色谱载体 [5,6 ] .Carr等 [7] 对碱性药物快速拆分表明氧化锆在手性分离Scheme1　 Structuresof chiral naproxen and its derivatives中的独特选择性 .萘普生及其衍生物在锆基手性固定相上的分离未见文献报道 .本组利用自制的球形氧化锆制备了涂敷型纤维素 -三 ( 3,5 -二甲基苯基氨基甲酸酯 ) -Zr O2 手性固定相 ( CDMPC- Zr O2 - CSP) ,在正…     

Photocatalytic degradation of trichloroethylene over BiOCl under UV irradiation

In this study, BiOCl samples were synthesized under different pH values and characterized by XRD, SEM, UV‐vis DRS, BET, photoelectrochemical measurement and PL. The photocatalytic performances of the as‐prepared samples were evaluated through the decomposition of trichloroethylene (TCE) under UV irradiation. The influences of several parameters such as solution pH and common inorganic anions on TCE removal were investigated. Results indicated that BiOCl‐0.6 exhibited better photocatalytic performance than BiOCl‐6.0 because of its higher migration ability of photo‐induced carrier. The photocatalytic degradation of TCE over BiOCl‐0.6 followed pseudo first‐order kinetics and appeared to be more efficient in acidic solution than in alkaline. TCE was almost completely dechlorinated in 120 minutes. The inhibiting effect of naturally occurring anions was in the order of HCO₃^‐ >SO₄^2‐ >NO₃^‐, while Cl^‐ exhibited a dual effect. Moreover, BiOCl‐0.6 exhibited superior reusability after three cycles of repetition tests.     

Ultrasound-assisted oxidative desulfurization of liquid fuels and its industrial application

Latest environmental regulations require a very deep desulfurization to meet the ultra-low sulfur diesel (ULSD, 15 ppm sulfur) specifications. Due to the disadvantages of hydrotreating technology on the slashing production conditions, costs and safety as well as environmental protection, the ultrasound-assisted oxidative desulfurization (UAOD) as an alternative technology has been developed. UAOD process selectively oxidizes sulfur in common thiophenes in diesel to sulfoxides and sulfones which can be removed via selective adsorption or extractant. SulphCo has successfully used a 5000 barrel/day mobile “Sonocracking” unit to duplicate on a commercial scale its proprietary process that applies ultrasonics at relatively low temperatures and pressures. The UAOD technology estimate capital costs less than half the cost of a new high-pressure hydrotreater. The physical and chemical mechanisms of UAOD process are illustrated, and the effective factors, such as ultrasonic frequency and power, oxidants, catalysts, phase-transfer agent, extractant and adsorbent, on reaction kinetics and product recovery are discussed in this review.     

Practical and Highly Selective C?H Functionalization of Structurally Diverse Ethers

A trityl ion mediated C H functionalization of ethers with a wide range of nucleophiles at ambient temperature has been developed. The reaction displays high chemoselectivity and good functional group tolerance. The protocol also exhibits excellent regio‐ and diastereoselectivities for the unsymmetric ethers, thus stereoselectively generating highly functionalized disubstituted 2,5‐trans tetrahydrofurans (THF), 2,6‐trans tetrahydropyrans (THP), 2,6‐trans dihydropyrans (DHP), and 1,3‐trans isochromans, and highlighting the capacity of the protocol in complex molecule synthesis.