π-Bindungsbeitrag in Boranen, 2. Mitt.:Ab initio- und Kraftfeld-Rechnungen von Vinyldifluorboran

Ab initio calculations on vinyldifluoroborane yield a -contribution of 23 kJ/mol (5.5 kcal/mol) mainly due to the C=C bond and not to the lone pairs of the fluorine atoms. The rotational barrier was also determined. The force field calculations favour the interpretation of the bond structure derived from the theab initio results.

     

DFT Study on the Structure of Ionic Liquid 1-Ethyl-3-methylimidazolium Hexafluorophosphate

1 INTRODUCTION Ionic compounds generally have high melting points and always exist in solid state since they are main- tained by electrovalent bonds. Ionic Liquids (ILs), which are liquids at or near ambient temperature, have been a class of ionic compounds extensively studied experimentally and theoretically in recent years[1, 2]. ILs consist exclusively of anions and ca- tions and do not contain any neutral molecule. They have many attractive properties, such as low vapor pressure, no…     

敏感性水凝胶及其应用研究进展

本文论述了各类敏感性水凝胶的发展历史和目前研究状况以及它们的应用研究进展,同时也对影响敏感性的凝胶结构因素和有关水凝胶敏感性相转变的物理解释作了简单介绍。     

A novel trilinear decomposition algorithm： Three-dimension non-negative matrix factorization

Non-negative matrix factorization(NMF)is a technique for dimensionality reduction by placing non-negativity constraints onthe matrix.Based on the PARAFAC model,NMF was extended for three-dimension data decomposition.The three-dimension non-negative matrix factorization(NMF3)algorithm,which was concise and easy to implement,was given in this paper.The NMF3algorithm implementation was based on elements but not on vectors.It could decompose a data array directly without unfolding,which was not similar to that the traditional algorithms do.It has been applied to the simulated data array decomposition andobtained reasonable results.It showed that NMF3 could be introduced for curve resolution in chemometrics.     

Y2O3薄膜处理对3Cr25Ni7N合金的抗高温氧化性能的影响

采用电沉积-热解法在3Cr25Ni7N合金表面制备了Y2O3薄膜,并研究了薄膜处理对合金在1000℃空气中的抗高温氧化性能的影响。氧化动力学曲线、SEM及XRD分析结果表明,Y2O3薄膜处理使合金表面氧化膜以尖晶石结构为主,氧化膜致密,有效地抑制了Cr2O3的挥发反应,且氧化膜与基体的附着性好,因此合金在高温下的抗氧化性能得到提高,这与氧化钇薄膜在较低温度下抗高温氧化性能提高的机制是不同的。在不同温度下,Y2O3薄膜处理均可以有效提高合金的抗高温氧化性能。     

Visible Up-Conversion Luminescence in Ho3+: BaTiO3 Nano-Crystals Prepared by Sol Gel Technique

Visible up-conversion emissions at (435, 545, 580, 675 and 690 nm) and (437, 547 575 and 675 nm) have been observed from the sol-gel derived nano-crystalline Ho³⁺: BaTiO₃ powders and thin films respectively, under 808 nm laser diode excitation emissions. Combined with the energy level structure of Ho³⁺ ions and the kinetics of the visible emissions, the up-conversion mechanism has been analyzed and explained. The blue, green and red emissions of both samples has been attributed to the ground state-directed transition from (⁵F₁), (⁵S₂) and (⁵F₅), which are populated through excited state absorption (ESA) for 808 nm excitation. Nano-structure pure barium titanate and doped with different concentrations of Ho³⁺ ions in the from of powder and thin film have been prepared by sol-gel technique, using barium acetate (Ba(Ac)₂), and titanium butoxide (Ti(C₄H₉O)₄), as precursors. The thin films were prepared by sol-gel spin coating method. The as-grown thin films and powders were found to be amorphous, which crystallized to the tetragonal phase after heating at 750°C in air for 30 minutes. The crystallite sizes of the thin film and powder both doped with 4% Ho³⁺ ions was found to be equal to 11 and 16 nm, respectvely.     

Three-dimensional structural features and the toxicity of aminobenzenes and phenols

There are many organic pollutants in the environment, such as polychlorinated biphenyl, polycyclic aromatic hydrocarbons, dichlorodiphenyl-trichloroethane (DDT), and polychlorinated naphthalene. These organic pollutants are persistent,liposoluble and easily cumulated in organism; consequently, the potential toxicity will be high. Risk assessment of industrial chemicals is currently carried out using scanty experimental data, because many of these chemicals have very little or no test data. S…     

Growth and Characterization of Crystal Nd_(0.06)Y_(0.94)Sr_6Sc(BO_3)_6

<正>The crystal of Nd0.06Y0.94Sr6Sc(BO3)6 with the dimensions up to 35 mm × 28 mm × 13 mm was grown by a top-seeded solution growth method from Li6B4O9 flux. The grown crystal was characterized by X-ray powder diffraction. The optical absorption of the crystal shows that it has a strong absorption band at 8070 A, and the absorption coefficient is 2.17cm-1 with a FWHM of 41 A, which can match with the wavelength of the diode-laser (LD) and is suitable for the LD pumping. Based on the Judd-Ofelt theory, the three parameters of line oscillator strength Ω(λ) (λ = 2, 4 and 6) of the Nd3+ion in the crystal were calculated as follows: Ω2= 1.194 × 10-20, Ω4= 4.186 × 10-20 and Ω6 = 3.351 × 10-20cm2, which are relatively larger. The results indicate that the crystal Nd0.06Y0.94Sr6Sc(BO3)6 may be a kind of high-efficient laser material for diode-pumped.     

Determination of proteins at nanogram levels by a resonance light-scattering technique with tetra-substituted sulphonated aluminum phthalocyanine

This is the first report on the determination of proteins with tetra-substituted sulphonated aluminum phthalocyanine (AlS₄Pc) by resonance light-scattering (RLS). At pH 3.0, the weak RLS of AlS₄Pc can be enhanced by the addition of proteins. Based on this, a novel quantitative method has been developed for the determination of proteins in aqueous solutions. Under optimal conditions, the linear ranges of the calibration curves were 0.050–2.0 μg ml⁻¹ for both human serum albumin (HSA) and human r-IgG. The detection limits were 12.7 ng ml⁻¹ for HSA and 16.1 ng ml⁻¹ for human r-IgG. The method has been applied to the analysis of total protein in human serum samples collected from the hospital and the results were in good agreement with those reported by the hospital, which indicates that the method presented here is not only sensitive, simple, but also reliable and suitable for practical applications.     

1－芳氧基乙酰基－4－邻氯苯甲酰基氨基硫脲衍生物的合成及其生物活性研究

于固－液相转移催化条件下，合成了１０个１－芳氧基乙酰基－４－邻氯苯甲酰基氨基硫脲衍生物，用元素分析、ＩＲ和￣１Ｈ－ＮＭＲ光谱确定了它们的结构。该类化合物对小麦幼苗生长具有明显的促进作用。