[en] The work in this thesis includes two aspects as described below: 1. Freshly produced red, yellow and green emitting porous Si have been fabricated and studied by NEXAFS and EXAFS. The emission peaks are at 690, 580 and 520 nm, which almost covers the fall visible range that direct anodization can achieve. The correlation between the co-ordination numbers of the first, second and third Si neighbour shells from Fourier transform fitting of EXAFS and both emission peak energies and optical bandgaps estimated by PLE (photoluminescence excitation dependence) suggests that the nanostructures of the PS are nanowires, rather than nanoclusters. Two types of quantum nanowire with one and one-plus-a-fraction dimensionality are proposed to interpret the correlation. The order factors of the theoretical fits suggest the nanowires of the freshly produced PS have crystalline cores. 2. Strong and stable blue photoluminescence (PL), visible to the naked eye under 0.4 μW of 300 nm and 2.7 μW of 370 nm excitation, has been observed for samples of Si and C clusters embedded in SiO₂ matrices, prepared by rf co-sputtering followed by N₂ annealing at 800 deg C. Firstly for the Si clusters. Si K-edge EXAFS and NEXAFS strongly suggest the existence of Si nanoclusters with crystalline cores in the efficient emitting material. On the other hand for the carbon clusters, silicon, carbon and oxygen K-edge XAFS suggest that 1) the nanoclusters present are C-based materials, 2) the luminescent materials probably involves π bonded carbon. The size distributions of both kinds of the nanoclusters obtained by TEM suggest that a quantum-confined size effect can also apply to the blue PL. The strong blue emission is related with the crystallisation of the nanodots by annealing. The PL excitation dependence is explained by an increase in the conduction band density of states deep in the band, and the formation of a band tail. (author)

[en] The subunit structure of the testicular LH/hCG receptor was studied by a chemical cross-linking technique. Leydig cells isolated from rat testis were incubated with ¹²⁵I-hCG, following which the bound ¹²⁵I-hCG was covalently cross-linked to the receptor on the cell surface with a cleavable or a non-cleavable cross-linking reagent. The hormone-receptor complex was extracted and then either subjected to gel permeation chromatography under nondenaturing conditions, or resolved by SDS-polyacrylamide gel electrophoresis, followed by autoradiographic analysis. The ovarian LH/hCG receptor was studied with luteal cells from pseudopregnant rats. Purification of the receptor was achieved by ligand affinity chromatography following detergent solubilization of the plasma membrane. The purified hCG receptor displayed properties identical to the membrane bound receptor with regard to binding specificity and affinity, and exhibited a molecular weight of approximately 130,000 dalton

[en] This paper compares the design of composite columns in steel and concrete based on EN1994-1-1 and Chinese JGJ138-2016. First, the application ranges of the codes are pointed out. Both codes contain the design of fully encased composite sections and concrete filled rectangular and circular tubes. However, there are different limitations on cross-section sizes, material strength classes, and others. JGJ138 has three separate chapters for the designs related to the three different types of columns. Eurocode 4 gives three different design methods: one general method based on nonlinear calculation, and two simplified methods based on European buckling curves or N-M iteration curves. For the materials, mechanical properties, such as design strength values, are compared based on the same material grade. For axial compression resistance and eccentrically compressive resistance, the two simplified methods from Eurocode 4 are compared with the design method according to JGJ138-2016 through theoretical and parameter studies. The influences of related parameters such as long-term effects, the buckling curves, and N-M iteration curves are also compared. For shear design, JGJ138-2016 considers mainly transverse shear resistances, while Eurocode 4 further considers shear connection and load introduction. The design transverse shear resistance is compared through theory. (Author)

[en] We have investigated the effects of Mn doping on the ferroelectric properties of Pb(Zr_0.3Ti_0.7)O₃ (PZT) thin films on substrates Pt/Ti/SiO₂/Si. Small amount of Mn-doped (≤1 mol%) PZT (PMZT) showed almost no hysteretic fatigue up to 10¹⁰ switching bipolar pulse cycles, coupled with excellent retention properties. We present evidence that while a low permittivity interfacial layer forms between the Pt electrode and PZT films, this does not occur in PMZT. We propose that Mn dopants are able to reduce oxygen vacancy mobility in PZT films and Mn²⁺ ions consume the oxygen vacancies generated during repeated switching, forming Mn⁴⁺ ions. These mechanisms are probably responsible for their low observed fatigue characteristics

[en] Direct contact condensation in stratified flow is an important phenomenon in LOCA analyses. In this report, the TRAC interfacial heat transfer model for stratified condensing flow has been assessed against the Bankoff experiments. A rectangular channel option has been added to the code to represent the experimental geometry. In almost all cases the TRAC heat transfer coefficient (HTC) over-predicts the condensation rates and in some cases it is so high that the predicted steam is sucked in from the normal outlet in order to conserve mass. Based on their cocurrent and countercurrent condensing flow experiments, Bankoff and his students (Lim 1981, Kim 1985) developed HTC models from the two cases. The replacement of the TRAC HTC with either of Bankoff's models greatly improves the predictions of condensation rates in the experiment with cocurrent condensing flow. However, the Bankoff HTC for countercurrent flow is preferable because it is based only on the local quantities rather than on the quantities averaged from the inlet. (author)

[en] The Bankoff experiments of condensation in counter-current stratified flow have been simulated by TRAC-PF1/MOD1 and modified TRAC with Bankoff's own correlations of interfacial friction and interfacial heat transfer coefficient (HTC). Steam flow rate and liquid height have been evaluated. Both TRAC and Bankoff HTCs are strongly dependant on the liquid velocity which is related to the liquid height. The calculations show that Bankoff HTC is much better than the TRAC HTC in the prediction of the stream flow rate and is recommended to replace TRAC HTC in the condensing stratified flow. (author)

[en] A sensitive and accurate method for the differential determination of trace amounts of arsenic(III) and arsenic(V) in water samples was described. It was found that arsenic(III) was coprecipitated quantitatively with a Ni-ammonium pyrrolidine dithiocarbamate (APDC) complex at the pH range of 2-3, but arsenic(V) was hardly coprecipitated with the Ni-PDC complex in the same pH condition. The coprecipitates obtained were directly measured by electrothermal atomic absorption spectrometry (ETAAS) using the solid sampling technique. In order to determine trace amounts of total arsenic, sodium thiosulfate and potassium iodide were used to reduce arsenic(V) to the trivalent state in the sample solution before coprecipitation. The concentration of arsenic(V) in the sample solution could be calculated by the difference in concentration between arsenic(III) and total arsenic in the sample solution. The coprecipitation conditions for trace amounts of arsenic(III) and arsenic(V) in water samples by the Ni-PDC complex were investigated in detail. The concentration factor by coprecipitation was reached at about 40 000 when 2 mg of nickel as a carrier element was added to 500 ml of the water sample. The proposed method was successfully applied to the determination of trace amounts of arsenic(III) and arsenic(V) in seawater, and the detection limit for arsenic, which was defined as the concentration calculated from three times of the standard deviation of the procedural blanks, was 0.02 ng/ml for 500 ml portions of water sample in the proposed method

[en] Based on Stefan-Boltzman and Lambert theorems, the radiation energy distribution on substrate (REDS) from catalyzer with parallel filament geometry has been simulated by variation of filament and system layout in hot-wire chemical vapor deposition. The REDS uniformity is sensitive to the distance between filament and substrate d_f-s when d_f-s≤4 cm. As d_f-s>4 cm, the REDS uniformity is independent of d_f-s and is mainly determined by filament number and filament separation. Two-dimensional calculation shows that the REDS uniformity is limited by temperature decay at filament edges. The simulation data are in good agreement with experiments

[en] This study was carried out to analyse the cultivar variability of the X-ray diffraction pattern of glutinous rice starches. Four peaks in the X-ray diffractograms were identified, i.e. 3b, 4a, 4b and 6a. The four peaks were measured from the base line for 71 cultivars and three M₃ lines which were irradiated by γ-rays at the rates of 10, 20 and 30 kr, respectively. Glutinous rice starches were classified into two types by discriminant analysis based on the values of 3b/4b, 4a/4b and 6a/4b. The X-ray diffraction type of the three cultivars did not change with the cultivation areas of different latitude, while that of eleven cultivars varied. Degree of crystallinity was estimated using the formula, (I_max — I_i)/I_max where I_max is the maximum height from background intensity line among cultivars, and I_i represents the four peaks. These ratios indicated that the changes in the order of crystallinity were similar to those with the water content and/or hydration and temperature for gelatinization among and/or within cultivars. (author)

[en] Some simple exact solutions of the Dirac equation useful in the study of π-condensation are reported. (orig.)