4-羟基香豆素及其衍生物的简便合成及其荧光性质的研究

用米氏酸和苯酚在无溶剂条件下以90.6%的收率合成丙二酸单苯基酯, 然后用Eaton试剂(五氧化二磷＋甲基磺酸)在温和条件下闭环, 以78.8%的收率得到4-羟基香豆素, 将这种方法扩展合成了苯环上带有各种取代基的4-羟基香豆素衍生物以及4-羟基硫代香豆素衍生物. 并对部分4-羟基香豆素衍生物的荧光性质进行了研究.     

3-氨基-4-硝基呋咱和3,3’-二硝基-4,4’-偶氮呋咱的合成研究

3-氨基-4-硝基呋咱(ANF)及其衍生物是一类重要的含能材料. ANF的制备首先以乙二醛、盐酸羟胺和氢氧化钠为原料, 经过两步反应制得3,4-二氨基呋咱(DAF), 采用新的氧化体系过氧化氢/甲烷磺酸/钨酸钠混合物(H2O2/CH3SO3H/ Na2WO4)代替原氧化体系过氧化氢/硫酸/过硫酸铵混合物[H2O2/H2SO4/(NH4)2S2O8]氧化DAF以67%的产率获得了ANF. 然后在单电子氧化体系高锰酸钾/盐酸混合物作用下ANF发生氧化反应以54.7%的产率得到3,3’-二硝基- 4,4’-偶氮呋咱(DNAzF). 研究表明过氧化氢/甲烷磺酸/钨酸钠混合物是制备氨基硝基单/多呋咱非常有效的氧化体系.     

The Story Behind the Link between Molecular Chirality and Crystal Shape

Here we describe the story behind the link between molecular chirality and macroscopic phenomena, the latter being a probe for the direct assignment of absolute configuration of chiral molecules. First, a brief tour of the history of molecular stereochemistry, starting with the classic experiment reported by Pasteur in 1848 on the separation of enantiomorphous crystals of a salt of tartaric acid, and his conclusion that the molecules of life are chiral of single-handedness. With time, this study raised, inter alia, two fundamental questions: the absolute configuration of chiral molecules and how a molecule of given configuration shapes the enantiomorphous morphology of its crystal. As for the first question, following the beginning of crystal structure determination by X-ray diffraction in 1912, it took almost 40 years before Bijvoet assigned molecular chirality through the esoteric method involving anomalous X-ray scattering. We have been able to address and link both questions through ‘everyday concepts of left and right’ (in the words of Jack Dunitz) by the use of ‘tailor-made’ auxiliaries. By such means, it proved possible to reveal, through morphology, etch patterns, epitaxy and symmetry reduction of both chiral and, paradoxically, centrosymmetric crystals, the basic chiral symmetry of the molecules of life, the α-amino acids and sugars.     

Synthesis,characterization and electrochemical investigation on Nickel Manganese Oxide - Polybutylene Sebacate composite electrode of biodegradable nature for micro capacitor applications

Synthesis, characterization, surface morphology and electrochemical properties of non-stochiometric Nickel–Manganese oxide nanoparticles were carried out by urea assisted sol gel method. The Ni_1-xMn_xO (0.15≤ X ≤ 0.50) nanoparticle synthesized was found to be cubic and the existence of Mn₃O₄ and MnO₂ phases were established and confirmed by X-ray Diffraction (XRD) studies. Thermo Gravimetric-Differential Thermal Analysis (TG-DTA) studies provided the calcination temperature of the xerogel at 600 °C, wherein the lattice strain and the size of the nanoparticles were determined through Williamson Hall (WH) Plot. The surface morphology characteristics of these nanoclusters were authenticated by Scanning Electron Microscope (SEM) techniques. Further, electroanalytical techniques were employed as a tool in establishing the nanocomposite as an intriguing material to act as a capacitor at enhanced efficiency compared to that of conventional capacitors. The electrochemical competence of the electrode was established through cyclic voltammogram, (CV) and Electrochemical Impedance Spectral (EIS) studies. The values of capacitance for Ni_1-xMn_xO, (0.15≤ X ≤ 0.5) nanoparticles varied from 7000 to 8000 mFg^?1, measured at 20 mVs^?1scan rate in 1.0 M Na₂SO₄and the temperature dependent conductance property for Ni_0.85Mn_0.15O electrode verified the Arrhenius Equation. The synthesis of a biodegradable polymer, Poly Butylene Sebacate (PBS) employed as conducting polymer for ultra capacitor applications is comparatively superior and definitely provides an edge over other capacitors in existence which is predominanantly attributed to its biodegradability nature. Further, the specific capacitance of PBS- Ni_0.85Mn_0.15O composite electrode was found to be 5180 mFg^?1 which clearly illustrates that these composites are potential candidates of the type biodegradable supercapacitors that are evolving transient sources of power in the future and the biodegradability of the polymer-metal oxide composite electrode fetches more significance in terms of disposal of electronic and electrical wares.     

真实情境下问题解决的主题式教学设计与实施*——盖斯定律

当前“盖斯定律”的教学中,注重加和法、虚拟路径法等解题模型的教学,缺乏在真实情境中对物质转化及其能量关系的理解,学生无法感受到盖斯定律在生产中的价值。本文以“能量视角下煤的气化对于提高煤的燃烧效率的意义”为研究主题,通过分析建模、实验验证、情境回归等认识并应用盖斯定律,从能量视角再认识煤的气化对于提高煤的燃烧效率的意义,并且认识到利用化学反应可以实现对能量进行调控,如对工业废热的再利用,深化能量守恒观和能源节约意识,达成提升学科核心素养的目标。     

On Attractors for Multivalued Semigroups Defined by Generalized Semiflows

In this paper we extend results from Semigroup Theory on existence and characterization of attractors in order to include multivalued semigroups T(t) defined by generalized semiflows . In particular we show that, if is continuous, possesses a Lyapunov function, and has a global attractor which is maximal compact invariant, then  =  W ^u (Z()), where Z() is the stationary solutions set and W ^u (Z()) is the unstable set of Z(). We introduce the -attractor concept which does not enjoy any uniformity on time of attraction and we prove, under suitable conditions, that the global -attractor is the set of asymptotic states described by Z(). Jacson Simsen is supported by CAPES-Brazil.