An Ensemble Kalman Filter Approach Based on Level Set Parameterization for Acoustic Source Identification Using Multiple Frequency Information

In this paper, a reconstruction problem of the spatial dependent acoustic source from multiple frequency data is discussed. Suppose that the source function is supported on a bounded domain and the piecewise constant intensities of the source are known on the support. We characterize unknown domain by the level set technique. And the level set function can be modeled by a Hamilton-Jacobi system. We use the ensemble Kalman filter approach to analyze the system state. This method can avoid to deal with the nonlinearity directly and reduce the computation complexity. In addition, the algorithm can achieve the stable state quickly with the Hamilton-Jacobi system. From some numerical examples, we show these advantages and verify the feasibility and effectiveness.     

PW11O39Co（Ⅱ）（H2O）5-的均相及异相体系可见光催化性能研究

以模型污染物罗丹明B（RhB）的光降解为探针,评估了Keggin型钴取代杂多阴离子PW₁₁O₃₉Co（Ⅱ）（H₂O）^5-（PW₁₁Co）及其异相体系PW₁₁Co/D301R的可见光催化活性,提出了光催化反应的机理,同时考察了催化剂用量、溶液酸度以及溶液中PW₁₁Co和RhB的相互作用对RhB可见光催化降解速率的影响。实验结果表明,PW₁₁Co均相体系及其异相体系PW₁₁Co/D301R对RhB的可见光降解均有较高的光催化活性,但与PW₁₁Co相比,PW₁₁Co/D301R的光催化活性更高。导致RhB降解的主要是羟基自由基。与PW₁₁Co均相体系相比,在PW₁₁Co/D₃₀₁R异相体系中由于PW₁₁Co与RhB的配位作用大为减弱,同时D301R对RhB具有富集作用,因而大大提高了RhB的光催化降解速率。     

三个基于Cu2X2(X-=Cl-、Br-和I-)结构单元双核Cu(Ⅰ)配合物的合成、晶体结构、电子吸收和发射光谱

合成并表征了3个含Cu₂X₂结构单元的双核Cu(Ⅰ)配合物[Cu₂(μ-X)₂(deebq)₂] (其中deebq=2, 2′-联喹啉-4, 4′-二甲酸乙酯;X=Cl (1), Br (2) or I (3))。化合物1~3同构, 其晶体属三斜晶系, 空间群为P1, 具有相似的晶胞参数和晶体堆积结构。Cu₂X₂双核单元具有反演中心对称性, 每个Cu⁺与deebq配体中2个N原子、2个μ₂桥联的卤素X^-阴离子配位, 形成扭曲的四面体配位环境。通过deebq配体中苯环间π…π堆积, 相邻双核分子形成超分子一维链, 超分子链间存在弱范德瓦尔斯引力。在二氯甲烷溶液中, 3个化合物都存在1个宽而不对称的电荷迁移吸收带(500~630 nm区域), 其强度和位置不受桥联X^-配体影响。因此, 电荷迁移带归属为由Cu⁺中心到deebq配体的电荷转移。在二氯甲烷溶液中, 3个化合物发射强荧光, 发射带中心波长位于400 nm处, 该发射带归属为deebq配体内的π-π^*电子跃迁。在固体以及二氯甲烷溶液中, 都没观察到从金属中心到配体的MLCT发射带。     

PW_(11)O_(39)Co(Ⅱ)(H_2O)~(5-)的均相及异相体系可见光催化性能研究

以模型污染物罗丹明B(RhB)的光降解为探针,评估了Keggin型钴取代杂多阴离子PW11O39Co髤(H2O)5-(PW11Co)及其异相体系PW11Co/D301R的可见光催化活性,提出了光催化反应的机理,同时考察了催化剂用量、溶液酸度以及溶液中PW11Co和RhB的相互作用对RhB可见光催化降解速率的影响。实验结果表明,PW11Co均相体系及其异相体系PW11Co/D301R对RhB的可见光降解均有较高的光催化活性,但PW11Co/D301R的光催化活性更高。导致RhB降解的主要是羟基自由基。与PW11Co均相体系相比,在PW11Co/D301R异相体系中由于PW11Co与RhB的配位作用大为减弱,同时D301R对RhB具有富集作用,因而大大提高了RhB的光催化降解速率。     

Synthesis and thermal properties of novel calix[4]arene derivatives containing 1,2,3-triazole moiety via K2CO3-catalyzed 1,3-dipolar cycloaddition reaction

Two calix[4]arene derivatives containing 1,2,3-triazole moiety were synthesized via K2CO3-catalyzed1,3-dipolar cycloaddition reaction between calix[4]arene-based azide and active methylene compounds in good yields.The structures of the two compounds synthesized herein were fully confirmed by 1HNMR,,（13）C NMR,and MS（ESI）.The thermal analysis showed that the mass losses of the synthesized compounds 4 and 5 containing 1,2,3-triazole groups are similar to each other.     

Micellization of anionic gemini surfactants and their interaction with polyacrylamide

A series of anionic gemini surfactants have been synthesized. The surface properties and micellization process of as-prepared sulfonate gemini surfactants (SGS) and carboxylate gemini surfactant (CGS) have been studied by surface tension measurement and isothermal titration microcalorimetry. Meanwhile, the interaction of these five surfactants with polyacrylamide (PAM) was investigated using surface tension, steady-state fluorescence measurement, and isothermal titration microcalorimetry. The results show that the critical micelle concentrations (CMCs) of above-mentioned surfactants are more than 1 order of magnitude lower than those of corresponding single chain surfactants. Moreover, the enthalpy of micelle formation (ΔH _mic) for the investigated gemini surfactants is negative. In the surfactant–PAM systems, the thermodynamic parameters of binding have also been determined. The conclusion may be drawn that the binding strength of SGS onto PAM is stronger than that of CGS, resulting from more compact structure of SGS aggregates. With increasing surfactant hydrophobicity, the values of ΔH _agg become more exothermic and a ΔS _agg decrease was observed. Therefore, the interaction between SGS and PAM is enthalpy-driven.     

“本博学位论文连做”培养模式的探索与研究*

“本博学位论文连做”培养模式是学士论文阶段在夯实理论基础的同时,改变本科阶段以学习课程为主的思维模式为以创新研究为主的思维模式;短暂的硕士阶段在理论知识进一步升华的基础上掌握本学科的研究现状和发展方向,提升发现问题、分析问题和解决问题的能力;博士阶段瞄准学科前沿,启发其发掘“新方法”和“新思路”,有效地实现学士学位论文和博士学位论文连做。     

两性霉素B与鞘磷脂单分子层的相互作用

选取哺乳动物生物膜中的重要脂质分子鞘磷脂(SM)作为单分子膜的基本组分, 采用Langmuir-Blodgett(LB)膜技术研究了不同比例的两性霉素B/鞘磷脂单层膜的表面压力-平均分子面积(π-A)曲线以及基于π-A曲线的混合性分析, 同时通过原子力显微镜(AFM)研究了其表面形态的变化. 结果表明, 组分间的摩尔比和表面压力对混合单层膜稳定性、混合性以及分子间相互作用具有重要影响.