Fe-57 Mossbauer spectroscopic measurements have been conducted on CuFe1-xGaxO2 single crystals, in order to investigate the magnetic structures and hyperfine parameters in ferroelectric CuFe0.965Ga0.035O2 and paraelectric CuFeO2. We confirmed that the Mossbauer spectrum at 4.2 K in CuFeO2 is explained by the collinear antiferromagnetic structure with spins along the hexagonal c-axis. In the ferroelectric phase in CuFe0.965Ga0.035O2, the spectrum consists of three magnetic components, where magnetic hyperfine fields distribute in three different directions within the (110) plane. This configuration is not completely consistent with a simple proper screw structure with a uniform spin distribution. The quadrupole coupling constants e(2)qQ/2 are unexpectedly large for both specimens. In the ferroelectric state in CuFe0.965Ga0.035O2, e(2)qQ/2 becomes noticeably smaller than that in the paraelectric phase in CuFeO2. We discuss the difference in quadrupole coupling constant between the ferroelectric and paraelectric states in CuFe1-xGaxO2.

57Fe Mössbauer spectroscopic study on ulvöspinel Fe2TiO4 has been conducted in a wide temperature range from 16 K to 500 K. The paramagnetic spectra are composed of several high spin Fe2+ doublets even at 500 K, which is rather strange because the point symmetry of the A-site is completely cubic (- 43m). We explain the electric field gradient (EFG) at A-site by the local arrangement of Fe2+ and Ti4+ on the B-site. The spectra were successfully analyzed by four-subspectra model, which is based on the B-site arrangement. The model also fits rather well to the magnetically ordered spectra. Thus the temperature variations of the hyperfine parameters were obtained. The Néel temperature (TN) is estimated to be about 125 K. The quadrupole coupling constants e2 qQ/2 of A-site subspectra show little change around cubic-tetragonal transition temperature (Tt = 163 K), but rapidly increase below TN. From the temperature variation of line width, we found local and dynamic Jahn-Teller distortions around A-site Fe2+ ions in the cubic phase. © 2013 Springer Science+Business Media Dordrecht.

The charge order in a perovskite manganite Pr0.5Ca0.5MnO3 was investigated by Mossbauer spectroscopy. The quadrupole splitting and the absorption line width jump to an increase when lowering the temperature below 230 K (T-co), which is indicative of a phase transition to a monoclinic structure due to the charge ordering, or due to a local Jahn-Teller effect due to the presence of Mn3+ ions. The intensity ratio of the doublet lines also changes at T-co. Local and dynamical Jahn-Teller effect (polarons) with a relaxation time of 10(-8) s is present even in the metallic state.

Mossbauer study on a Y-type hexaferrite Ba2Mg2Fe12O22 has been conducted by using a single crystal specimen. The spins are in the c-plane down to 60 K. For 18h(VI) site Fe, the quadrupole shifts and the outermost line width change around 195 K, where the transition from ferrimagnetic to proper screw spin structure takes place. Below 50 K, the spin reorientation transition to a longitudinal conical structure was also recognized. At 16 K, the spins incline about 15 degrees from the c-plane.

The charge order in a perovskite manganite Pr0.5Ca0.5MnO3 was investigated by Mossbauer spectroscopy. The quadrupole splitting and the absorption line width jump to an increase when lowering the temperature below 230 K (T-co), which is indicative of a phase transition to a monoclinic structure due to the charge ordering, or due to a local Jahn-Teller effect due to the presence of Mn3+ ions. The intensity ratio of the doublet lines also changes at T-co. Local and dynamical Jahn-Teller effect (polarons) with a relaxation time of 10(-8) s is present even in the metallic state.

Mossbauer study on a Y-type hexaferrite Ba2Mg2Fe12O22 has been conducted by using a single crystal specimen. The spins are in the c-plane down to 60 K. For 18h(VI) site Fe, the quadrupole shifts and the outermost line width change around 195 K, where the transition from ferrimagnetic to proper screw spin structure takes place. Below 50 K, the spin reorientation transition to a longitudinal conical structure was also recognized. At 16 K, the spins incline about 15 degrees from the c-plane.

In order to recover and recycle the valuable metals, such as Mo, Ni and V on γ-Al₂O₃ supported catalyst, which has been used for desulfurization in petroleum refining process, three step process, i.e. air-oxidation roasting step at temperatures from 400 to 900°C, alkaline leaching step using sodium hydroxide and carbonate solution and hydrogen reduction-hydrochloric acid leaching step, has been experimentally conducted for its process feasibility. It has been known that NiAl₂O₄ spinel compound formation in the roasting step hinders the leaching of Ni, which leads us to the reducing-acid leaching step of the alkaline leach residue. It has been shown that (1) in the roasting step, better elimination of hydrocarbon and sulfur constituents is attained at temperature at temperatures, 700 to 900°C, with resultant formation of Mo and V oxides and Ni spinel compound, (2) better leaching rate of Mo and V, 97% and 89% respectively, and the least leaching rate of Al (around, 0.6%) using sodium carbonate solution and (3) high Ni leaching rate of 80% has been attained in the final step. Thus, using this three step process, reasonable rate recovery of Mo, V and Ni has been shown feasible and this process scheme could be applicable for recovery Mo, Co and V in desulfurization catalysis.

In the CO₂ reforming reaction using CH₄, carbon precipitation on metal catalysis takes place making the catalysis inactive and useless. In this study, we have suggested two reaction pathways of carbon deposition process on Pd8 (111) cluster in CO₂-CH₄ reforming reaction, which are i.e. Path 1 and Path 2, shown below;<BR>Path 1<BR>       CO+^* → CO-^*<BR>       CO-^*+CO → C-^*+CO₂<BR>Path 2<BR>       CO+^*+^* →  C-^*+O-^*<BR>       O-^*+CO → CO₂+^*<BR>   where ^* is a adsorption site on a catalysis.<BR>The results obtained in the analysis of these two reaction pathways using ab initio molecular orbital method are as follows: (1) energy profile diagrams of those reaction pathways to elucidate the preferred pathway of carbon deposition and (2) electron transfer and population analysis from and to the Pd cluster. Through this analysis, Path 2 appears the preferred reaction path in the present carbon precipitation reaction scheme.

In this study, in order to elucidate benzene decomposition reaction path on V₂O₅ catalysis, ab initio molecular orbital calculation has been conducted for 5 elemental reaction steps involved in the reaction between benzene and V₂O₉H₈ cluster, proposed by Jaine, et al., i.e. benzene adsorption, hydrogen atom surface transfer, hydrogen gas de-sorption, oxygen gas adsorption and benzene ring decomposition. Molecular structures in stable state, transition state and intermediate molecular structures have been revealed in this proposed reaction steps. The reaction scheme can be described as follows; (1) electron in benzene transfer themselves to the catalysis cluster, whereby hydrogen atom transfer on the catalysis surface proceeds for the subsequent hydrogen molecular gas de-sorption, and (2) benzene ring decomposition takes place via the unique Mars-van Krevelen mechanism on V₂O₅ catalysis.

An array of copper (Cu) nanodots was fabricated onto a Si substrate covered with native oxide (SiO2/Si) using a diblock copolymer as a resist film. First, polystyrene/polymethylmethacrylate (PS/PMMA) diblock copolymer was spin-coated on a SiO2/Si substrate and then annealed for 24 h in a vacuum oven maintained at 170 degrees C to achieve good phase separation. To prepare a nanotemplate, this phase-separated diblock copolymer film was photodecomposed selectively using 172 nm vacuum ultraviolet (VUV) light. Due to the difference in photoetching rate between PS and PMMA domains, the latter regions were preferentially decomposed. By controlling the VUV irradiation conditions, that is, exposure time and atmospheric pressure, we were able to prepare a diblock copolymer template comprised of a nanoporous PS matrix on the SiO2/Si surface. Next, the nanopore regions were site-selectively modified through a vapor phase chemisorption of an amino-terminated organosilane. Palladium (Pd[II]) particles were then immobilized onto the amino-terminated nanopore regions through donor and accepter reactions and, subsequently, Cu was selectively electroless-plated onto these Pd-activated regions. As evidenced by atomic force microscopy, due to the elimination of the residual PS nanotemplate by VUV irradiation, we fabricated an array of Cu nanodots 3.0 to similar to 4.3 nm in height and 10 to similar to 25 nm in diameter on the entire 10 x 10 mm(2) area of the SiO2/Si substrate. (c) 2005 American Vacuum Society.

We evaluated structural changes of poly (methyl-methacrylate) (PMMA) surfaces after and before vacuum ultraviolet (VUV)-irradiation using X-ray photoelectron spectroscopy (XPS) and Fourier trans form infrared spectroscope reflection absorption Spectroscopy (FTIR-RAS). When the PMMA films were irradiated with VUV light under reduced pressure of 10⁰Pa, XPS measurements showed that the O/C value decreased from 0.40 before VUV irradiation to 0.10 after irradiation at 10⁰Pa for 10 min. FT-IR spectral results indicated that C=O and ester peaks, which are parts of PMMA structures, were reduced by the VUV-irradiation. These results showed that oxygen-groups existed on the PMMA surface were decom posed by VUV-irradiation at 10⁰ Pa. However, these structural changes weren't observed when the PMMA was irradiated at 10³ Pa. Furthermore, we confirmed that C=O and ester peaks were reduced by VUV-irradiation at N₂ atmosphere. This result was the same as the case of VUV-irradiation at 10⁰ Pa. Although unirradiated PMMA was removed by toluene rinsing, the cured PMMA by VUV-irradiation at 10⁰ Pa could not dissolve. Utilizing these properties, we could prepare negative and positive-tone PMMA micropattems by VUV-light lithography through a photomask.

This paper describes a method to fabricate high-density copper microstructures on an indium tin oxide (ITO) surface. Lithography using 172-nm vacuum ultraviolet (VUV) light was found to not decompose the siloxane network at the bottom of a methyl-terminated organosilane self-assembled monolayer (SAM) deposited on an ITO substrate. When copper was electrodeposited onto this ITO surface covered a SAM/siloxane network pattern, it deposited selectively onto the siloxane regions. However, the density of the electrodeposited copper was low. By applying a wet hydrofluoric (HF) acid treatment for an appropriate time after the lithography, we could effectively remove the siloxane network without damaging the organosilane SAM. In this manner, we were able to successfully fabricate high-density copper microstructures with 35 x 35 mum patterns. (C) 2004 Elsevier B.V. All rights reserved.

This paper describes a simple and effective method to fabricate built-in copper microstructures on a polymer substrate. Our method uses a micropatterned amino (NH2)-terminated self-assembled monolayer (SAM) as a template to fabricate patterned copper (Cu) film for transfer to an epoxy resin. Cu microstructures were first formed on a photolithographically micropatterned NH2-SAM-covered SiO2/Si substrate through conventional electroless plating, in which Cu deposition proceeded selectively on the NH2-terminated areas while the photo-irradiated areas remained free of copper deposits. Next, epoxy glue (resin) was poured into a Teflon(R) O-ring placed so as to surround the Cu-micro-patterned substrate. Finally, after the resin completely hardened, it was removed from the substrate. Due to the weak adhesion between the Cu film and the NH2-terminated surface, the area-selectively deposited Cu film could be readily peeled off and removed from the SiO2/Si substrate and thus transferred to the resin surface. Through this technique, high-resolution 10-mum-wide Cu microstructures were successfully fabricated on the epoxy resin surface. These embedded Cu microstructures were tightly adhered to the resin. No peeling of the copper structures was observed in a Scotch(R) tape peeling test. (C) 2004 Elsevier B.V. All rights reserved.

The photoinduced stability of two alkyl monolayers on Si has been investigated using a Xe-2 excimer lamp radiating 172 nm vacuum ultraviolet (VUV) light. The photoinduced stability of I-octadecene monolayer (ODM) was compared with that of alkylsilane monolayer. I-octadecene was employed as a starting precursor of alkyl monolayer on Si. The alkylsilane monolayer was formed from otadecyltrimethoxysilane monoalyer (OTSM) onto the SiO2/Si substrate. The decomposition of ODM was investigated under VUV irradiation conducted at 10 and 10(5) Pa. The VUV light decomposed ODM at both 10 and 105 Pa. The photodecomposition rate at 105 Pa was smaller than that at 10 Pa. The decomposed methyl and ethyl groups from the alkyl chain formed carboxyl groups. The carboxyl coverage on the surface of Si increased with increasing VUV irradiation time ranging from 0 to 60 s at 10 Pa, and decreased after 60 s. In contrast, the Si-O component in x-ray photoelectron Si 2p spectrum drastically increased after the VUV irradiation time of 60 s. The Si-O component indicated complete covering of Si surface. Similar decomposition rates between ODM and OTSM were observed for the VUV irradiation time ranging from 0 to 45 s conducted at 10 Pa. After 45 s, the photodecomposition rate of ODM was smaller than that of OTSM. The effectiveness of VUV light for the micropatterning of ODM was also investigated. (C) 2004 American Vacuum Society.

The control of the surface wettability of poly (methyl methacrylate) (PMMA) substrates has been successfully demonstrated using an Ar-2* excimer lamp radiating 126 nm vacuum ultraviolet (VUV) light. Each of the samples was exposed to 126 nm VUV light in air over the pressure range of 2 x 10(-4)-10(5) Pa. Although at the process pressures of 10, 10(3), and 10(5) Pa, the PMMA surfaces became relatively hydrophilic, the degree of hydrophilicity depended markedly on the pressure. The minimum water contact angles of the samples treated at 10, 10(3), and 10(5) Pa were about 50degrees, 33degrees, and 64degrees, respectively. These values were larger than those of PMMA substrates hydrophilized through 172 nm VUV irradiation conducted under the same conditions. On the other hand, after 126 nm VUV irradiation conducted under the high vacuum condition of 2 x 10(-4) Pa, the PMMA substrate surface became carbon-rich, probably due to preferential cross-linking reactions, as evidenced by x-ray photoelectron spectroscopy. This surface was hydrophobic, showing a water contact angle of about 101degrees. Although the 126 nm VUV-irradiated surfaces appeared relatively smooth when observed by atomic force microscope, very small particles with diameters of 30-60 nm, which probably originated from the readhesion of photodecomposed products, existed on all of the sample surfaces. (C) 2004 American Vacuum Society.

ZnTe thin films were electrodeposited onto Au-coated Cu substrates from an electrolytic solution containing ZnSO4, TeO2, citric acid and sodium citrate, and the dependence of structure, composition and surface morphology on the solution's Zn concentration were investigated. Results of examinations for resistivity and optical absorption demonstrated, respectively, that as the Zn concentration in the electrolyte was reduced over the range of 5-50 mmol dm(-3), the resistivity of the films obtained continuously decreased and their band gap increased. Quantative analysis of energy dispersive x-ray analysis and inductively coupled plasma results indicated that the composition ratio (Zn: Te) was approximately stoichiometric under all conditions in this study. X-ray diffraction results revealed that all the ZnTe thin films obtained showed a preferred (111) orientation with cubic structure. ZnTe thin films we transferred onto nonconductive epoxy resin also showed the same structure.

Copper-tellurium films were electrochemically deposited from a Solution containing CuCl2, TeO2 and HCl This study revealed the relationship between the copper/tellurium ratio in the Solution and the metal ratio in the deposited film. The Cu/Te ratio of the deposited film was successfully controlled by conducting electrodeposition under diffusion-limited conditions. The [Cu]/[Te] ratio in the solution was linearly related to that of Cu/Te in the deposited film, since the partial current density originating from the copper and tellurium ions was directly proportional to the concentration of each. The deposited films crystallized to Cu,Te at the Cu/Te ratio of 2.5. The films were deposited at -0.4 V vs. Ag/AgCl from a solution in which [Cu]/[Te] = 2.5, [CuCl2] = 1.0 x 10(-3) M ( kmol m(-3)), [TeO2] = 4.0 x 10(-4) M. and pH = 1.

The difference in chemical reactivity between indium-tin-oxide (ITO) and self-assembled monolayer (SAM) surfaces was used to fabricate copper (Cu) microstructures. ITO substrates coated with octadecyltrimethoxysilane (ODS)-SAM were photolithographically micropatterned using vacuum ultraviolet (VUV) light Each of the micropatterned samples was subsequently immersed in an electrodeposition bath in order to deposit Cu on its surface. As confirmed by atomic force microscopy, Cu electrodeposition proceeded selectively on the VUV-irradiated areas of the ITO surface while the ODS-SAM surface served effectively as a mask to block Cu deposition. Cu microstructures with 7.5 X 7.5 mum(2) features were successfully fabricated on the ITO surface. (C) 2003 American Vacuum Society.

We have investigated the elementary reaction path on the 3,3′,4,4′,5,5′-hexachlorinated biphenyl (HxCB) formation from two 1,2,3,5-tetrachlorobenzenes (TCBz) and the catalytic role of copper on this formation using ab initio molecular orbital calculation. The elementary reaction path on the 3,3′,4,4′,5,5′-HxCB formation from two 1,2,3,5-TCBzs has been shown to occur as follows: Step 1 - the dissociation of Cl atom substituted at 5-position in 1,2,3,5-TCBz, Step 2 - the association between Cl atom substituted at 5-position in another 1,2,3,5-TCBz and the Cl radical formed in Step 1, Step 3 - the elimination of Cl2 molecule from the intermediate species formed in Step 2, and Step 4 - the 3,3′,4,4′,5,5′-HxCB formation from the direct condensation of two 1,2,3-trichlorophenyl radicals formed in Step 1 and Step 3. The geometric factor, which decides the reactivity of this formation, is the C-Cl bond strength of 1,2,3,5-TCBz. The catalytic roles of copper are to stabilize the total energy in the adsorption of 1,2,3,5-TCBz onto the copper surface and to weaken the C-Cl bond strength due to the charge transfer from the 1,2,3,5-TCBz to the copper surface. Moreover, we have achieved the prediction of the minimum energy path on the formation of non- and mono-ortho polychlorinated biphenyls congeners for which TEFs have been determined. © 2002 Elsevier Science Ltd. All rights reserved.

A simulation model of the Imperial Smelting Furnace has been developed to improve the furnace operation. The model consists of top, shaft and bottom regions. Analysis in the shaft region is based on differential heat and materials balances taking account of reaction kinetics and heat transfer rate, and those in the top and the bottom regions are based on heat and materials balances under steady-state condition. Overall heat and materials balances, and longitudinal distributions of process variables such as temperatures of gas, sinter and coke, volume-flow rate of gas, mass-flow rates of sinter, coke and molten lead, gas composition and fractional conversion in the shaft region under a practical operating condition were calculated. The heat loss through the furnace wall and the temperature distribution calculated using the model are in good agreement with those observed. The model is capable of predicting any change in the furnace situation when the operating condition is altered.

Using the simulation model of the Imperial Smelting Furnace based on differential heat and materials balances developed by the authors, the behavior of ISF under various operating conditions was predicted, where the influence of change in an operating condition on furnace performance was estimated. The main findings are as follows:<BR>(1) With decreasing coke reactivity, zinc productivity increases and coke ratio decreases.<BR>(2) There are an optimum size of particle and an optimum height of charge for the furnace performance.<BR>(3) Pulverized coke injection improves the furnace performance.<BR>Analysis of furnace performance using the model is useful for further improvement of the furnace operation.

A mathematical simulation model of the imperial Smelting Furnace operation has been developed for purpose of improving the furnace operation. The model consists of top, shaft and bottom regions. Analysis in the shaft region is based on differential heat and materials balances taking account of reaction kinetics and heat transfer rates, and those in the top and the bottom regions are based on heat and materials balances under a steady-state condition. Longitudinal distributions of process variables such as temperatures of gas, sinter and coke, gas composition and fractional conversion under a practical operating condition were calculated. With this model, the furnace performance under various operating conditions also can be shown reasonably predicted.

The influence of sulfur dioxide addition on dioxins generation and decomposition behaviors has been evaluated by thermodynamic equilibrium calculations. The calculation conditions in this work were as follows: (1) the C-H-O-Cl quaternary system has the ratio of [C : H : O : Cl]=9 : 6 : 4 : 1, i.e. this system corresponds to the most typical generation region of dioxins, (2) total amount of respective elements (N_C+N_H+N_O+N_Cl) is 1 mol, (3) sulfur dioxide is then added to this C-H-O-Cl quaternary system and (4) total pressure and temperature range were 1 atm and from 773 to 1773 K. The influence of sulfur dioxide addition is shown to change the oxygen potential, on which the dioxins generation and decomposition is independent, i.e. higher temperature and higher oxygen potential lead to dioxins decomposition. The essential effect of sulfur element is shown to reduce hydrogen chloride potential, leading less dioxins chlorination reaction.

Yttria-stabilized zirconia (YSZ) has high potential to be used as solid-oxide-fuel cell (SOFC) electrolyte. However, the high efficiency of SOFC has nut been yet achieved due to the high internal resistance of bulk electrolyte The resistance becomes lower with the decrease in the electrolyte thickness. Thus, the decrease in electrolyte thickness leads to lower internal resistance. The aim of this study is as follows: (a) to prepare the thin films of YSZ by inductively-coupled RF plasma-enhanced metal organic chemical vapor deposition (PEMOCVD) process using Zr(t-OC4H9)(4),Y(DPM)(3) and oxygen, and (b) to reveal the relationship between the structural characterizations and the process parameters.

Ternary compound-semiconductor, CuInTe2, film was deposited cathodically under potentiostatic conditions on titanium substrate From aqueous solution containing CuCl2, InCl3, TeO2 and HCl in this study. Tnt deposition parameters such as electrolytic solution composition, potential and temperature were optimized for electrodeposition of CulnTe(2). Structural characterization of the deposited film was also carried out using XRD and SEM. Electrodeposited films were prepared and analyzed for their chemical composition using ICP. The ICP analyses showed that the stoichiometry of the films could be controlled by (1) the deposition potential and/or by (2) the electrolytic bath composition.

Owing to their extremely high toxicity in the environment, the dioxins have been attracting social, technical and scientific attention in recent years. The authors theoretically had predicted the thermodynamic properties of all the dioxins via quantum chemistry and statistical thermodynamics and elucidated the generation-decomposition behavior of dioxins in the equilibrium calculation of C-H-O-Cl system. In actual combustion processes, it is said that metallic compounds have much influences on the dioxins behavior. The aim of this study is to reveal the roles of metallic compounds the generation-decomposition behavior of dioxins is revealed from the viewpoints of quantum chemistry. Especially, the catalytic effect of copper has been investigated for the reaction, 2HCl(g)--&gt;H-2(g)+Cl-2(g) and for the etherification reaction from precursors, which is Phenol(g) here, to dioxins. The catalytic role of Cu is shown to have much influence on the generation -decomposition of dioxins.

The standard electrode potential for Cu is 0.34V and that of In is -0.34 V, which means that their deposition potentials are far apart, making the co-deposition difficult from a simple solution containing Cu and In ions. In order to bring these deposition potntials closer, a complex forming reagent of citric or EDTA is added to the CuSO4-In-2(SO4)(3) solution. The effect of these reagents was examined by linear sweep veltammetric measurement. An electrochemical deposition experiment of Cu-In alloy was conducted where effect citric acid or EDTA addition, current density and Cu concentration were examined.

In order to elucidate the reaction mechanism for the Tetraethoxysilane (TEOS) thermal decomposition at atmospheric pressure, its pertinent elemental reactions involving the SiO(OC2H5)(2) reaction intermediate were first proposed. For respective species formed in these elemental reactions, the total energy and the electronic state were calculated using a semi-empirical molecular method. The adsorption process which involves adsorbent species formation and surface reaction mechanism were then analyzed from the standpoint of molecular orbital formation and charge transfer mechanism, and the results are summarized as follows:
(1)! A reaction intermediate, SiO(OC2H5)(2)((1)A(1)), is probably formed through the following p-elimination reaction route: Si(OC2H5)(4)((1)A(1)) --&gt; SiO(OC2H5)(2)((1)A(1))+C2H4((1)A(1)) +C2H5OH((1)A(1))
(2) The adsorption of SiO(OC2H5)(2)((1)A(1)) on SiO2 occurs with charge transfer from the dangling bond of silicon atom at an active site of the SiO2 surface to the pi*-LUMO unoccupied orbital of SiO(OC2H5)(2)((1)A(1)).
(3) The sequence of surface reactions is considered as follows:
(1) First, a dissociation reaction of C2H5((2)A') takes place, whereby producing a double bond between silicon atom and oxygen atom of the intermediate, since they possess unpaired electrons.
(2) Si-O bond is successively formed following the mechanism similar to the one operating in the adsorption of SiO(OC2H5)(2)((1)A(1)) on SiO2.
(3) Electronic state of the reactant finally formed is in the (1)A(1) state, which has a sigma-orbital to be fully occupied with electrons.

The pressure dependent rate constant for the reaction, SiH4 (g) --&gt;SiH3 (g) + H, has been unknown from the standpoints of both experiment and calculation. It is the basic data of the reaction path analysis for RPT (Reduced Pressure Thermal)-CVD from silane, and hence it is a valuable piece of information in science and technology in view of the reaction control. In this study, the pressure dependent rate constant was predicted using the RRKM theory aided by Ab-initio MO. It was calculated under conditions in which the temperatures were from 600 to 1500 K at intervals of 100 K, the pressures were 135.32 x 10(10), 133.32 x 10(8), 133.32 x 10(6), 133.32 x 10(4), 101.32 x 10(3), 133.32 x 10(2), 133.32 x 10(1), 133.32 x 10(0), 133.32 x 10(-1),133.32 x 10(-2) and 133.32 x 10(-3)(Pa), and the third body was argon gas. The Arrhenius type rate expression was shown as follows:
k(133.32 x 1010) = 1.94 x 10(16) exp (-45316/T) =k(high)
k(133.32 x 108) = 1.93 x 10(16) exp (-45316/T), k(133.32 x 106) = 1.22 x 10(16) exp (-44990/T),
k(133.32 x 104) = 9.25 x 10(14) exp (-43412/T), k(101.32 x 103) = 9.27 x 10(13) exp (-42406/T),
k(133.32 x 102) = 1.28 x 10(13) exp (-41909/T), k(133.32 x 101) = 1.31 x 10(12) exp (-41752/T),
k(133.32 x 100) = 1.29 x 10(11) exp (-41717/T), k(133.32 x 10-1) = 1.28 x 10(10) exp (-41708/T),
k(133.32 x 10-2) = 1.27 x 10(9) exp (-41704/T), k(133.32 x 10-3) = 1.27 x 10(8) exp (-41704/T).
Here, the subscript of k stands for the pressure.

From our previous experimental study of the Si chemical vapor deposition in Si2Cl6-H2 system, the following elementary reaction mechanism was proposed: decomposition of Si2Cl6 to produce SiCl2, which becomes the adsorbent
Si2Cl6(g) → 2SiCl3(g) → SiCl4(g) + SiCl2(g) (→ SiCl2(a)), and hydrogen reduction reaction of the absorbed SiCl2 to produce Si(s). The preliminary quantum chemistry study for this reaction mechanism has shown that the reaction is so infeasible that the above-mentioned elementary reaction mechanism is unreasonable. The most feasible and appropriate reaction mechanism has been shown as follows: (Step 1) Si2Cl6(g) → SiCl4,(g) + SiCl2(g) (Step 2) SiCl2(g) +a → SiCl2(a) (Step 3) SiCl2(a) + H2(g) → SiCl(a) + 2HCl(g) (Step 3-1) SiCl2(a) + H2(g) → Si-2HCl(a) (Step 3-2) Si-2HCl(a) → Si(a) + 2HCl(g) where, a is the active site on silicon surface. On the assumption that step 3 is the rate-determining step, this elementary reaction mechanism can explain the experimental observation in the rate expression on the concentration dependence with respect to Si2Cl6 and H2.

In this investigation, respective thermodynamic parameters of heats of formation, standard entropy and specific heat capacity at constant pressure for PCDDs, PCDFs, Co-PCB and PCBs as well as polychlorinated-benzens and polychlorinated-phenols have been evaluated by quantum chemical calculation using a semi-empirical molecular orbital method with the PM3 Hamiltonian and statistical thermodynamic correlation The values of heats of formation for the dioxin substances and their precursors are calculated in the range of +/- 200 kJ/mol. The tolerance analysis indicates that the maximum discrepancy with experimental values would be reasonably estimated to be +/- 28 kJ/mol. The values of standard entropy for these compounds would be in the range of + 270 to + 500 kJ/mol K, and the estimated discrepancy between the calculated and experimental heats of formation would be in the range of + 1 to + 9 J/mol K.

The effect of the crystal structure of various nickel substrates on the orientation of plated gold films was studied. The gold plating was conducted in a solution primarily composed of gold potassium cyanide at 338K and pH=6.5 with a current density of 5mA/cm². It was found that the crystal structure of the nickel substrate influenced the orientation of the gold film as follows: (i) for films thinner than 0.2μm, there was epitaxial growth of gold film on the nickel substrate as (111)Au||(111)Ni, (200)Au||(200)Ni and (220)Au||(220)Ni: (ii) for films between 0.2 and 3μm, there was growth of the (110) plane of gold on the nickel substrates; and (iii) for films thicker than 3μm, the growth plane orientations were (111)>(220)>(200), which is considered the characteristics of gold plating under these condition.