Advanced Materials Research Vols. 233-235

Abstract: N-(2-pyridylmethyl)-L-phenylalanine methyl ester was synthesized in our laboratory，and the title compound was synthesized by the reaction of N-(2-pyridylmethyl)-L-phenylalanine methyl ester and Zinc acetate dehydrate. Bis(L-α-N-(2-pyridylmethy)phenylalaninato-N, N', O)-Zinc(II) trihydrate was prepared and structurally characterized by X-ray diffraction. It crystallizes in orthorhombic, space group P2₁2₁2 with a= 15.0928 (8), b = 16.4209 (6), c = 5.9930 (3) Å, V = 1485.29 (12) ų, Z = 2, M_r = 630.00, D_x = 1.409 g/cm³, μ = 0.88 mm^-1, F(000) = 660, R_int = 0.0205, R = 0.028 and wR = 0.059 for 2943 observed reflections with I > 2σ(I). It is a mononuclear discrete structure. The zinc atom coordinates with two oxygen and four nitrogen atoms from two ligands in a distorted octahedral geometry, with the oxygen atom from the carboxylate, two of nitrogen atoms from NH parts and the other two nitrogen atoms from the pyridine ring. With three free water molecules, the present structure has a network of hydrogen bonds.

Abstract: The means of homogenization method and finite element method was deduced to predict the effective properties of nano-modified plastics. Steps of simulation were given. The effective properties of EVA/TiO₂ nanocomposites were studied by the content and the shape of nanoparticles. The results of the prediction and the test were close basically. It was showed that the method of predicting the effective properties of nano-modified plastics by means of homogenization method and finite element method was feasible and the effects of actual microstructures of materials could be investigated too.

Abstract: The optical limiting properties of CuPcTs, NiPcTs and CoPcTs were investigated with nanosecond pulses at the wavelength of 532nm. Among them, CuPcTs exhibits the strongest optical limiting effect. An explanation based on nonlinear absorption and refraction is provided. And also, the relationship between the d-electron configuration and the third-order nonlinear optical properties of CuPcTs, NiPcTs and CoPcTs were discussed.

Abstract: In this paper, we analyzed the chemical composition of the essential oil from Datura Stramonium L. and determined their phytotoxic activity on five cultivated crops. The main components of essential oil were sterols and their derivatives, and the major constituents were 5.alpha.-Ergosta-7,22-dien-3.beta.-ol (16.53%), 3-Hydroxycholestan-5-yl, acetate (14.97%), and 26,26-Dimethyl-5,24(28)-ergostadien-3.beta.-ol (10.39%). The essential oil and its aqueous saturated solution from D. Stramonium significantly inhibited the germination and growth of lettuce, radish, common bean, maize, and cucumber. The results indicated that D. Stramonium may release allelochemicals, both water-soluble and volatile compositions, into environment to inhibit other plant species.

Abstract: A new photochromic diarylethene1-(3,5-dimethyl-4-isoxazolyl)-2-(2-methyl-3- benzofuran) perfluorocyclopentene (1a) has been synthesized. Its photochromic, fluorescent and optical strorage properties were investigated. The compound exhibited remarkable photochromism and clear fluorescent switches both in solution and in PMMA film. The results showed that the cyclization/cycloreversion process of the compound was determined to be the zeroth/first order reaction. This new photochromic system also exhibited remarkable optical storage character.

Abstract: Two kinds of organosilicate precursors, trimethylsilane (3MS) and diethoxymethylsilane (DEMS), were used to produce low-k films by plasma-enhanced chemical vapor deposition (PECVD) in this work. The experimental results indicate that DEMS-based low-k films have superior electrical performance and better thermal stability as compared to 3MS-based low-k films. Therefore, DEMS-based films are the promising low-k materials which can be integrated in very large scale integration circuit as an inter-layer dielectric material.

Abstract: Adsorption refrigeration is an effective way to use low-grade energy sources such as industrial waste heat without damaging the environment. A novel exhaust-driven adsorption icemaker on a fishing boat is introduced in this paper. Based on the previous study, combining with the single adsorption cooling tube technique, this paper presents an adsorption cooling unit with unique structure driven by exhaust waste heat (hereinafter referred to as "waste heat cooling tube" WHCT). Different with the previous tubular structured adsorption bed, WHCT is made of seamless stainless steel pipe, the adsorbent bed, evaporator / condenser are all placed in one tube. Adsorption working pair of calcium chloride-ammonia has been proposed and developed for adsorption cooling. The working principle and structure are introduced in this paper.

Abstract: In hot slab continuous casting (CC) process, the Machine Vision (MV) inspection method for slab surface defects has been becoming a research focus with the development of charge-coupled device (CCD) camera imaging technologies. To acquire a informative and reliable defects image is a prerequisite that means a maximum defects detection rate and minimum false recognition in the next image processing stage. In this paper, based on the CCD imaging principle and definition evaluation algorithm, the slab surface radiation feature at high temperature and CCD optical imaging properties had been analyzed under the focal plane, meanwhile, the CCD image definition of optical integral time controlling method had also been studied, which the defect image variance (IV) function, image average gradient (IAG) and information entropy (IIE) were calculated and analyzed. In the end, the image definition controlling algorithm for hot slab surface ROI imaging that adopted IIE evaluation algorithm, based on CCD integral time imaging controlling principle, had been proposed. This method also can support practical value for other machine vision engineering.

Abstract: To improve the retrieval rate of contourlet transform texture retrieval system, a contourlet-2.3 transform based retrieval system was proposed. Six different features, including mean, standard deviation, absolute mean energy, L2 energy, skewness and kurtosis contributions to retrieval rates were examined. Based on the single feature ability in retrieval system, a contourlet-2.3 retrieval system was proposed. The feature vectors were constructed by cascading the standard deviation, absolute mean energy and kurtosis of each sub-band contourlet coefficients and the similarity measure used here is Canberra distance. Experimental results on 109 brodatz texture images show that the new retrieval algorithm can lead to a higher retrieval rate than several contourlet transform retrieval systems including the original contourlet transform, non-subsampled contourlet transform under the same structure.

Abstract: WO₃-based varistors doped with Y₂O₃ were prepared and the microstructure, nonlinear electrical properties, and dielectric properties were investigated. Breakdown voltages E_b of WO₃ doped with Y₂O₃ are lower than that of undoped WO₃, indicating that the dopant can reduce the breakdown voltage. The dielectric constant of doped samples is higher than that of undoped samples, and the high dielectric constant makes them suitable as capacitor-varistor materials. It was found that the sample of WO₃-0.5 mol% Y₂O₃ sintered at 1150 °C has an optimal nonlinear coefficient of 3.4 and a breakdown voltage of 17.1 V/mm. WO₃ ceramic doped with Y₂O₃ is a new kind of low voltage capacitor-varistor material.