Semiempirical prediction of the hyperpolarizabilities for cyanovinyl-substituted donor-acceptor molecules

We present here a systematically theoretical study on the nonlinearities and their structure-property relationship of cyanovinyl-substituted donor-acceptor molecules by virtue of semiem-pirical PM3/AM1-FF approach.Good consistency between measured and calculated hyperpolarizabil-ities is obtained.Results show that conformation has a significant effect on hyperpolarizabilities.The torsion angle change between two conjugated parts of the molecular systems can substantially alter the nonlinearities.The total amount of charge transfer difference from donor to acceptor has been introduced to understand the microscopic nature of the nonlinear optical properties for the title molecules.General guidelines may be sought out in the search of molecules with large values of β Some molecules with large molecular hyperpolarizabilities can be predicted by the optimization for the longer π-electron systems with both acceptor and donor groups.     

RUPTURING OF POLYMER FILMS WITH RUBBING-INDUCED SURFACE DEFECTS

It has been a long-standing question whether dewetting of polymer film from non-wettable substrate surfaceswherein the bicontinuous morphology never forms in the dewetting film is due to spinodal instability or heterogeneousnucleation. In this experiment, we use a simple method to make the distinction through introduction of topographical defectsof the films by rubbing the sample surface with a rayon cloth. Spinodal dewetting is identified for those films that dewet by acharateristic wavevector, q, independent of the density of rubbing-induced defects. Heterogeneous nucleation, on the otherhand, is identified for those with q increasing with increasing density of defects. Our result shows that PS films on oxidecoated silicon with thickness less than ≈ 13 nm are dominated by spinodal dewetting, but the thicker films are dominated bynucleation dewetting. We also confirm that spinodal dewetting does not necessarily lead to a bicontinuous morphology in thedewetting film, contrary to the classic theory of Cahn.     

Synthesis and Antimicrobial Properties of the Novel Fluonnated Bis-ammonium Salts with Two Primary Amine Groups

In order to resolve the increasing resistance phenomena of the Gram-negative bacteria against single chain quaternary ammonium salts (QAS), lysine with a pedant fluorinated bis-ammonium salts was synthesized and its antimicrobial properties were evaluated in this work. The novel fluorinated bis-ammonium salts shows similar activity with conventional single chain quaternary ammonium salts against Gram-positive bacteria but stronger activity against Gram-negative bacteria and yeast compared with the single chained counterpart.     

Synthesis and reactions of 2-[α-(3,4-disubstituted phenacyl)-p-substituted styryl]-4H-3,1-benzoxazin-4-ones

Science Department, Faculty of Teachers, P.O.Box 2313, Al Hasa, 31982, Saudi Arabia Faculty of Engineering, Ain Shames University, EgyptChemistry Department, Faculty of Science, Ain Shames University, Egypt     

Unusual Luminescence of Ca8[Al12O24]（WO4）2： Tb^3＋

The luminescence properties of aluminate sodalite Ca8[Al12024](WO4)2 (CAW) undoped and doped with Th^3 are reported and discussed. At room temperature the emission of tetrahedral WO4^2- in CAW showed an abnormally small Stokes shift (9060 cm^-1), which is related to the crystal structure of CAW. A strong absorption band in the excitation spectrum of the Th^3 -activated CAW is ascribed to the absorption of the charge transfer state Th^4 -W^5 , into which the excitation resulted in the efficient emission from the ^5D4 level of Tb^3 , but not from the ^5D3 level.     

Palladium Catalyzed Synthesis of Fluorine-containing 3-Biaryl-1-ferrocenyl-2-propene-1-one

In the last two decades, molecular-based second-order nonlinear optical (NLO) chromo-phores1, have attracted much interest because of their potential applications in emerging 2opto-electronic technologies. These efforts have mainly focused on organic systems.More recently, organometallic molecules have been investigated as well. In comparisonto common organic molecules, they offer a large variety of novel structures3, . The 4possibility of high environmental stability, and divers…     

Synthesis of a New Cobalt (II) Complex and its Interaction with DNA

The interaction of metal complexes with DNA has been widely studied by differentmethods such as spectrophotometry, light scattering technique, fluorometry1-3. Manycomplexes such as Co(phen)2 ,Co(en)2 ,Fe(EDTA)2- etc.4,5 have been synthesized and 3+ 3+their effect on DNA has been studied in order to further explain the mechanism of genemutation, anti-cancer or cancer-induced reason and DNA targeted drugs. In this paper,a new cobalt complex was synth…     

Site-specific Deposition of Colloidal Pd Nanoparticles on Self-assembled Microtubules from Biolipid

Lipid microtubules with wound ribbon features were fabricated by self-assembling method, and the deposition patterns of colloidal Pd particles on tubular template were investigated. The result indicates that colloidal Pd nanoparticles are preferentially decorated on the helical markings in the interior and on the exterior of preformed tubule and to the edge of loosely helical ribbons to obtain helical deposition features. The multi-bilayer microstructure of tubules can be marked by fine Pd nanoparticles deposited at the edge of helical ribbon. There are the site-specific interactions between lipid tubular template and colloidal Pd particles at the helical edge. A new route was illustrated that colloidal Pd particles firstly attach at the edge of thin flat membranes, and then thin membranes roll up and reassemble into tubule together with particles to form helical deposition patterns. The site-specific deposition of Pd is unbeneficial to obtain the homogeneous metal film on tubules, but it can be utilized to reveal the different chemical nature of lipid molecular assembly.     

离子交换法从发酵液中提取L-异亮氨酸

采用天然高分子絮凝剂壳聚糖对L-异亮氨酸发酵液进行预处理，在发酵液pH=2，壳聚糖用量30mg／L的条件下可取得较好的絮凝效果．并通过静态吸附实验，考察了pH和L—异亮氨酸浓度对平衡吸附量的影响．最后确定了732″离子交换树脂提取L-异亮氨酸的最佳工艺条件：上柱发酵液pH=2，上样速度0．6BV／h，洗脱液为0.5mol／L的NH4Cl．流出液经脱色、浓缩结晶后得L-异亮氨酸成品，总提取率为55％．     

Effect of Chemical Treatment on TiO2 Particles by IMPS

The photodegradation reaction rate of CHCl3 in TiO2 particulate suspension was imperoved significantly by HCl-treatment.The effect of HCl-treatment on the photocatalytic activity of TiO2 was strdied in a PEC cell by using Intensity-Modulated Photocurrent Spectroscopy(IMPS).The magntude of photocurrent response and the characteristic frequencies of the upper and lower semicircles in the complex plane of IMPS response were analyzed,and the ccathodic and anodic reaction processes of photogenerated holes and electrons were discussed.The increases in the cathodic and anodic photocurrent response and in the time constants of both cathodic and anodic reaction processes of photogenerated holes and electrons were discussed.The increases in the cathodic and anodic photocurrent response and in the time constants of both cathodic and anodic reaction processes indicate that HCl-treatment leads to the improvement of the photocatalytic activity of TiO2 and a change of the photocatalytic kinetic mechanism.