Wear resistant coating of cemented carbides and high speed steels by chemical vapour deposition

Ti(N, C, O), which has been chosen as a coating material for cutting tool inserts, was prepared on cemented carbides and high speed steels by chemical vapour deposition via a gas mixture of TiCl₄, H₂, N₂, CH₄ and CO₂ under reduced pressure. This coating layer is characterized by fine grain size and freedom from porosity. The coated tool inserts show excellent cutting performance.     

Substituent effects on thermal and photo‐alignment behavior of poly(ethylene imine)s carrying azobenzene side groups

A new class of liquid‐crystalline poly(ethylene imine)s (PEIs) having four differently substituted (? CN,? C₄H₉,? OCH₃ and? NO₂) azobenzene side‐chain groups attached through alkyl spacer groups were successfully synthesized using a solution polycondensation reaction. The synthesized polymers were characterized using differential scanning calorimetry, polarized optical microscopy and X‐ray diffraction. The photochemical, thermo‐optical and photo‐orientational behavior of the polymers were investigated in detail. Spin‐coated films of PEIs with azobenzene groups having? C₄H₉,? OCH₃ and? NO₂ substituents showed out‐of‐plane molecular orientation on annealing. Except for the PEI with an azobenzene group having ? NO₂ substituent, all polymers exhibited good photoresponsive properties upon irradiation with UV and visible light. Films of PEIs with azobenzene side groups having? CN,? C₄H₉ and? OCH₃ substituents showed reversible alignment behavior from random state to out‐of‐plane and from out‐of‐plane to random state on annealing and on irradiation with UV and non‐polarized visible light. The reversibility of the molecular orientation of PEIs from random state to out‐of‐plane and from out‐of‐plane to random state greatly depended on the substituent attached to the azobenzene side‐chain group. Copyright © 2010 Society of Chemical Industry     

Standardized evaluation of chemical compositions of LiTaO3 single crystals for SAW devices using the LFB ultrasonic material characterization system

The line-focus-beam ultrasonic material characterization (LIFB-UMC) system is applied to compare and evaluate tolerances provided independently for the Curie temperature T/sub C/ and lattice constant /spl alpha/ to evaluate commercial LiTaO/sub 3/ single crystals by measuring the Rayleigh-type leaky surface acoustic wave (LSAW) velocities V/sub LSAW/. The relationships between VLSAW, and T/sub C/ and /spl alpha/ measured by individual manufacturers were obtained experimentally using 42/spl deg/YX-LiTaO/sub 3/ wafers as specimens from three crystal manufacturers. In addition, the relationship between VLSAW and SH-type SAW velocities V/sub SAW/ that are actually used for the SAW device wafers was obtained through calculations, using the chemical composition dependences of the acoustical physical constants for LiTaO/sub 3/ crystals reported previously. The result of a comparison between the T/sub C/ tolerance of /spl plusmn/3/spl deg/C and the /spl alpha/ tolerance of /spl plusmn/0.00002 nm through the common scale of VLSAW or VSAW demonstrated that the /spl alpha/ tolerance is 1.6 times larger than the T/sub C/ tolerance. Furthermore, we performed a standardized comparison of statistical data of T/sub C/ and /spl alpha/ for LiTaO/sub 3/ crystals grown by two manufacturers during 1999 and 2000, using VLSAW. The results clarified the differences of the average chemical compositions and of the chemical composition distributions among the crystal ingots between the two manufacturers. A guideline for the standardized evaluation procedure has been established for the SAW-device wafer specifications by the LFB-UMC system.     

Serum selenium contents and the risk of cancer

To investigate the relationship between serum Se contents and the risk of cancer, 4857 serum samples were obtained from cancerous (2730) and non-cancerous patients (2127). In this cohort, the incidence of cancer in the non-cancerous patients was followed for the subsequent 3 years. The serum Se level of non-cancerous patients who later developed cancer during the 3 years was determined and compared with that of the non-cancerous patients. A high incidence of cancer was observed in the lower serum Se patients of the non-cancerous group. The serum Se levels of cancerous patients were significantly lower than in non-cancerous patients. These results suggest that the low serum Se level in cancerous patients may not be induced by the tumor but it was more likely already present before the tumor. To calculate the odds ratio, cancerous and non-cancerous patients were divided into group of less than 110 ppb and more than 111 ppb group in serum Se. The odds ratio was estimated to be 1.95, suggesting the high risk of cancer in the low serum Se group.     

Phase relations associated with the aluminum blast furnace: Aluminum oxycarbide melts and Al-C-X (X=Fe,Si) liquid alloys

The thermodynamic properties and the phase relations were evaluated and estimated for the Al-O-C, Al-Si-C, and Al-Fe-C systems which are important to understand the chemical behavior in an aluminum blast furnace. The mixing properties of binary liquid alloys, including metal-carbon systems, were represented by the Redlich-Kister equation. The properties of liquid Al−C and Si−C alloys were estimated so as to be consistent with their phase diagrams. The coefficients of Al−Fe and Fe−C liquids were evaluated from reported values for activity and enthalpy. The extrapolation to the higher order systems was made by Maggianu's method. The aluminum oxycarbide melt was represented by a subregular solution model. In the Al-O-C system, liquid alloy/oxycarbide melt equilibria were calculated and compared with earlier experimental results and estimates. Attempts were made to clarify the volatilization of aluminum oxycarbide melts, and also the carbidation of liquid aluminum alloys. An empirical correlation between the first terms of the Redlich-Kister equation for the enthalpies and the excess entropies was discussed.     

Solution Growth and Thermoelectric Properties of Single-Phase MnSi<Subscript>1.75−<Emphasis Type="Italic">x</Emphasis></Subscript>

We have investigated the crystal growth of single-phase MnSi_1.75−x by a temperature gradient solution growth (TGSG) method using Ga and Sn as solvents and MnSi_1.7 alloy as the solute, and measured the thermoelectric properties of the resulting crystals. Single-phase Mn₁₁Si₁₉ and Mn₄Si₇ crystals were grown successfully using Ga and Sn as solvents, respectively. The typical size of a grown ingot of Mn₁₁Si₁₉ was 2 mm to 4 mm in thickness and 12 mm in diameter, whereas Mn₄Si₇ had polyhedral shape with dimensions in the range of several millimeters. The single-phase Mn₁₁Si₁₉ has good electrical conduction (ρ = 0.89 × 10⁻³ Ω cm to 1.09 × 10⁻³ Ω cm) compared with melt-grown multiphase higher-manganese silicide (HMS) crystals. The Seebeck coefficient, power factor, and thermal conductivity were 77 μV K⁻¹ to 85 μV K⁻¹, 6.7 μW cm⁻¹ K⁻² to 7.2 μW cm⁻¹ K⁻², and 0.032 W cm⁻¹ K⁻¹, respectively, at 300 K.     

Radiation damage of bipolar SST due to γ rays of Co

In order to investigate radiation hardness of the bipolar SST transistors, transistor samples were exposed to gamma rays from an intense ⁶⁰Co source. The transistor samples were hard up to a total dose of the order of 10⁴ Gy.     

Effect of KCA-098, a new benzofuroquinoline derivative, on bone mineral metabolism

The effect of 3,9-bis(N,N-dimethylcarbamoyloxy)-5H-benzofuro[3,2-c]quinoli ne-6-one designated as KCA-098) on the bone mineral metabolism of chick embryonic bone was examined. KCA-098 dose-dependently inhibited bone resorption of cultured chick embryonic femora and calvariae. It increased the length, dry weight, and calcium and phosphorus contents of 9-d-old chick embryonic femurs cultivated for 6 d, indicating that it stimulated bone formation. These results show that KCA-098 has the unique effects of inhibiting bone resorption and stimulating bone formation of chick embryo. In addition, in an in vivo experiment, oral administration of KCA-098 (3.0 mg/kg/d) for 16 weeks led to an increase in calcium and phosphorus content as well as an increase in the amount of force required to break the femur from ovariectomized rats, suggesting that it may be useful for the treatment of bone diseases.     

High performance poly(urethane-imide) prepared by introducing imide blocks into the polyurethane backbone

A series of novel linear poly(urethane-imide)s were synthesized by the reaction between isocyanate-terminated polyurethane (PU) prepolymer and amine- or anhydride-terminated oligoimide. PU prepolymer was synthesized by reacting polyethylene adipatediol of molecular weight 1000 with tolylene-2,4-diisocyanate at the molar ratio of 2:3 or 1:2. Oligoimide was synthesized from the reaction of 4,4′-(hexafluoroisopropylidene)diphthalic acid with 4,4′-oxydianiline at various molar ratios. Equimolar amounts of PU prepolymer and oligoimide were reacted in N-methyl-2-pyrrolidone, followed by casting on glass plates and heat treatment at 100 and 150 °C for 1 h each to give linear poly(urethane-imide)s as transparent yellowish brown films. Poly(urethane-imide) films with less of 30% of imide component became elastomer, and films with more than 36% imide component became plastic. The effects of end-groups of oligoimide, molecular weight of oligoimide, and molecular weight of PU prepolymer on the solvent resistance, the tensile properties, viscoelastic properties, and thermogravimetric properties of poly(urethane-imide) films were systematically examined. Solvent resistance and tensile modulus of poly(urethane-imide) films from amine-terminated oligoimides were better than those from anhydride-terminated oligoimides. On the other hand, thermal stability and elongation at break for the poly(urethane-imide) films from anhydride-terminated oligoimides were higher than those from amine-terminated oligoimides.