8-丙烯酰氧喹啉及其聚合物增感的丙烯腈光聚合

<正> 我们曾研究过电子给体基团和电子受体基团共存于同一分子中的一类功能性单体,如甲基丙烯酸-4-(N,N)-二甲氨基苄酯(DMABMA)、N-(4-N′,N′-二甲氨基苄基)丙烯酰胺(DMAPAA)、8-丙烯酰氧喹啉(AQ)。N-丙烯酸-N′=苯基哌嗪(APP)等     

Hydrolysis Reaction of N-Phosphoryl-α-, β- and γ-amino Acids Studied by HPLC

The hydrolysis reactions of N-（O,O＇diisopropyl）phosphoryl-L-α-alanine （DIPP-L-α-Ala）, N-（O,O＇diisopropyl）- phosphoryl-D-α-alanine （DIPP-D-α-Ala）, N-（O,O＇-diisopropyl）phosphoryl-β-alanine （DIPP-β-Ala） and N-（O,O＇-diisopropyl）phosphoryl-γ-amino butyric acid （DIPP-γ-Aba）, were studied by HPLC and their hydrolysis reaction kinetic equations were obtained. Under acid conditions, the reaction rate of DIPP-L-α-Ala was close to that of DIPP-D-α-Ala and the same rule was true between DIPP-β-Ala and DIPP-γ-Aba. Meantime, the reaction rate of DIPP-L/D-α-Ala was as 10 times as that of DIPP-β-Ala or DIPP-γ-Aba. Under basic conditions, the hydrolysis reactions of DIPP-β-Ala and DIPP-γ-Aba almost did not take place and the reaction rate of DIPP-L/D-α-Ala was about 1/10 of that under acid conditions. Moreover, theoretical calculation further illuminated the differences of the hydrolysis rate from the view of energy. The results would provide some helpful clues to why nature chose a-amino acids but not other kinds of analogs as protein backbones.     

New Thiophene Derivatives with Two-photon Excited Fluorescence

Organic molecules that can simultaneously absorb two or more photons in reaching theirexcited states have recently been the subject in various photon-electronic fields. Tomeet the criteria for various nonlinear optical applications, such as three-dimensionaloptical storage1 and up-converted lasing2, molecules with large two-photon absorption(TPA) cross-section σ are required and have been synthesized. These dyes generallybelong to the structural modes of D-π-D, A-π-A3 or D-π-A, where D…     

Exponential Synchronization of the Linearly Coupled Dynamical Networks with Delays

In this paper,the authors investigate the synchronization of an array of linearly coupled identical dynamical systems with a delayed coupling.Here the coupling matrix can be asymmetric and reducible.Some criteria ensuring delay-independent and delay- dependent global synchronization are derived respectively.It is shown that if the coupling delay is less than a positive threshold,then the coupled network will be synchronized.On the other hand,with the increase of coupling delay,the synchronization stability of the network will be restrained,even eventually de-synchronized.     

乙酸介质中构筑苝酰亚胺染料长纳米线

合成了一种带酰胺基的苝酰亚胺. 紫外-可见光谱表明, 该化合物在乙酸和体积分数大于40%的乙酸水溶液中于647 nm附近出现“黑相”的特征吸收, 苝生色团采取in-phase方式排列; 而在乙醇和体积分数小于40%的乙酸水溶液中于571 nm附近出现“红相”的特征吸收, 苝生色团采取interdigital方式排列. SEM和TEM照片显示, 黑色固体的微观形态为长达数百微米, 直径为100~200 nm的纳米线, 而红色固体则为长度为几微米的梭状结构. 用紫外-可见和红外光谱监测了随着乙酸浓度的降低和介质改变, 固体由黑相到红相的转变, SEM图像还显示, 在体积分数为40%的乙酸水溶液中存在长纳米线解体和短的梭状结构形成的转变过程.     

The Existence and Long-Time Behavior of Weak Solution to Bipolar Quantum Drift-Diffusion Model

The authors study the existence and long-time behavior of weak solutions to the bipolar transient quantum drift-diffusion model,a fourth order parabolic system.Using semi-discretization in time and entropy estimate,the authors get the global existence of nonnegative weak solutions to the one-dimensional model with nonnegative initial and homogenous Neumann(or periodic)boundary conditions.Furthermore,by a logarithmic Sobolev inequality,it is proved that the periodic weak solution exponentially approaches its mean value as time increases to infinity.     

Interaction of Chelerythrine Choloride in Acid Buffer with Calf-thymus DNA

Several benzo[c]phenanthridine alkaloids (BPA) were found in plants of Caprifoliaceae, Fumariaceae, Meliaceae, Papaveraceae, and Ruracea families1. BPA represent a group of natural products, exhibiting multiple pharmacological properties and biological ac…     

Refolding with Simultaneous Purification of Recombinant Human Granulocyte Colony-stimulating Factor from Escherichia coli Using Strong Anion Exchange Chromatography

Human granulocyte colony-stimulating factor (hG-CSF), a single chain polypeptidecontaining 174 amino acid residues (MW=18,800, pI=6.1), is one of the hemopoieticgrowth factors which plays an important role in stimulating proliferation, differentiation,and functional activation of bloodcells1. It contains a free cysteine at position 17 andtwo intramolecular disulfide bonds, Cys36-Cys42 and Cys64-Cys74, and the two disulfidebonds in G-CSF molecule are both required for its bioactivity2. Wh…     

Gnetuhainin P, a New Isorhapontigenin Dimer from the Lianas of Gnetum hainanense

Continuous investigation on oligostilbenes from the lianas of Gnetum hainanense resulted in the isolation of a new rhapontigenin dimer, Gnetuhainin P (1), in addition to the dimers of resveratrol and oxyresveratrol reported previously1. Gnetuhainin P (1) was obtained as a yellowish amorphous powder, [(]25D +6.6 (c 0.092, MeOH). The high resolution FABMS m/z 533.1866 [M+H]+ gave a molecular formula of C30H28O9 (C30H29O9 requires 533.1812), which corresponds to a isorhapontigenin dimer. …     

Characterization of Formation Kinetics of Self-Assembled Thiol Monolayers on Gold by Electrochemical Impedance Spectroscopy

Interest in the properties of organized monolayers has grown enormously in recent years because these monolayers can provide a means to control the interface at a molecular level1. The self-assemblies of alkanethiols and their derivatives were probably the most intensively studied due to their stability, well-packed structure, ease in preparation, and flexibility in designing the tail group2. The adsorption kinetics of thiol monolayer has been studied by using several techniques, including con…