A high-powered A.C. plasma torch for the arc heating of molten steel in the tundish

Current user's requirements for excellent product quality means that producers must discover the isothermal casting conditions which trill lead to top operating performance in the continuous casting process. In response to this requirement. a high-powered A. C. plasma arc heating system was adopted for the No. 4 Continuous Caster (No. 4CC) put into operation at Kakogawa Works. This heating system is a single-phase A.C. plasma type with two torches. This report describes research on the molten steel heating technique utilized by the A. C. plasma system, the effects of tundish atmosphere on the characteristics of plasma electric potter, and the counter- measures devised to increase the arc voltage using a suitable torch structure.     

Solvation dynamics in aqueous anionic and cationic micelle solutions: sodium alkyl sulfate and alkyltrimethylammonium bromide

Solvation dynamics of the fluorescence probe, coumarin 102, in anionic surfactant, sodium alkyl sulfate (C(n)H(2n+1)SO(4)Na; n = 8, 10, 12, and 14), and cationic surfactant, alkyltrimethylammonium bromide (C(n)H(2n+1)N(CH(3))(3)Br; n = 10, 12, 14, and 16), micelle solutions have been investigated by a picosecond streak camera system. The solvation dynamics in the time range of 10(-10)-10(-8) s is characterized by a biexponential function. The faster solvation time constants are about 110-160 ps for both anionic and cationic micelle solutions, and the slower solvation time constants for sodium alkyl sulfate and alkyltrimethylammonium bromide micelle solutions are about 1.2-2.6 ns and 450-740 ps, respectively. Both the faster and the slower solvation times become slower with longer alkyl chain surfactant micelles. The alkyl-chain-length dependence of the solvation dynamics in both sodium alkyl sulfate and alkyltrimethylammonium bromide micelles can be attributed to the variation of the micellar surface density of the polar headgroup by the change of the alkyl chain length. The slower solvation time constants of sodium alkyl sulfate micelle solutions are about 3.5 times slower than those of alkyltrimethylammonium bromide micelle solutions for the same alkyl-chain-length surfactants. The interaction energies of the geometry optimized mimic clusters (H(2)O-C(2)H(5)SO(4)(-) and H(2)O-C(2)H(5)N(CH(3))(3)(+)) have been estimated by the density functional theory calculations to understand the interaction strengths between water and alkyl sulfate and alkyltrimethylammonium headgroups. The difference of the slower solvation time constants between sodium alkyl sulfate and alkyltrimethylammonium bromide micelle solutions arises likely from their different specific interactions.     

Synthesis of polyamides by direct polycondensation with (1,2-benzisoxazol-3-yl) diphenyl phosphate as a new activating agent

A new activating agent for amide condensations, (1,2-benzisoxazol-3-yl) diphenyl phosphate ( 1 ), was readily prepared in high yield by the reaction of 1,2-benzisoxazol-3-ol ( 2 ) with diphenyl phosphorochloridate ( 3 ) in the presence of triethylamine in benzene. The new activating agent 1 was found to be very useful for the preparation of amides from carboxylic acids and amines. The direct polycondensation of several dicarboxylic acids with aromatic diamines using the activating agent 1 in the presence of triethylamine proceeded slowly at room temperature to produce polyamides with inherent viscosities up to 1.2 dL g^?1.     

A new BOD estimation method employing a double-mediator system by ferricyanide and menadione using the eukaryote Saccharomyces cerevisiae

A new biochemical oxygen demand (BOD) sensing method employing a double-mediator (DM) system coupled with ferricyanide and a lipophilic mediator, menadione and the eukaryote Saccharomyces cerevisiae has been developed. In this study, a stirred micro-batch-type microbial sensor with a 560 μL volume and a two-electrode system was used. The chronamperometric response of this sensor had a linear response between 1 μM and 10 mM hexacyanoferrate(II) (r² = 0.9995, 14 points, n = 3, average of relative standard deviation and R.S.D._av = 1.3%). Next, the optimum conditions for BOD estimation by the DM system (BOD_DM) were investigated and the findings revealed that the concentration of ethanol, used to dissolve menadione, influenced the sensor response and a relationship between the sensor output and glucose glutamic acid concentration was obtained over a range of 6.6-220 mg O₂ L⁻¹ (five points, n = 3, R.S.D._av 6.6%) when using a reaction mixture incubated for 15 min. Subsequently, the characterization of this sensor was studied. The sensor responses to 14 pure organic substances were compared with the conventional BOD₅ method and other biosensor methods. Similar results with the BOD biosensor system using Trichosporon cutaneum were obtained. In addition, the influence of chloride ion, artificial seawater and heavy metal ions on the sensor response was investigated. A slight influence of 20.0 g L⁻¹ chloride ion and artificial seawater (18.4 g L⁻¹ Cl⁻) was observed. Thus, the possibility of BOD determination for seawater was suggested in this study. In addition, no influence of the heavy metal ions (1.0 mg L⁻¹ Fe³⁺, Cu²⁺, Mn²⁺, Cr³⁺ and Zn²⁺) was observed. Real sample measurements using both river water and seawater were performed and compared with those obtained from the BOD₅ method. Finally, stable responses were obtained for 14 days when the yeast suspension was stored at 4 °C (response reduction, 93%; R.S.D. for 6 testing days, 9.1%).     

Characteristic fragmentations of peptide derivatives containing proline in negative-ion fast atom bombardment mass spectrometry

Fragmentations of N-benzyloxycarbonyl-protected tripeptide ethyl esters containing proline were compared with those of the corresponding peptide derivatives not containing proline in negative-ion fast atom bombardment mass spectrometry. The fragment ion [M – 109]^? due to loss of the benzyloxy group followed by dehydrogenation from the peptide molecule was the base peak in the negative-ion mass spectra for the peptides not containing proline, whilst it was a very weak fragment ion or not observed at all in those for the peptides containing proline. These results suggest that the fragmentations of the peptide derivatives in negative-ion fast atom bombardment mass spectrometry depend on the conformational difference of the peptide derivatives owing to the existence of proline in the derivative.     

Chemical processing on microchips for analysis, synthesis, and bioassay

This review describes our recent research on miniaturization of chemical systems. We have developed a miniaturization methodology based on pressure-driven multiphase laminar flow and a highly sensitive detection tool, the thermal lens microscope. Some representative applications of the methodology in the fields of analysis, synthesis, and bioassay are described.     

Total Synthesis of (±)-Nanaomycin A and (±)-Frenolicin

Efficient synthesis of (±)-nanaomycin A and (±)-frenolicin from a versatile intermediate is described.     

Selective reduction of NO2 by propylene in excess oxygen over Rh/Al2O3. DRIFT spectroscopy and activity studies

A DRIFT study has shown that similar surface species are formed on Rh/Al₂O₃ during the selective catalytic reduction of NO₂ or NO by C₃H₆, indicating that the reduction of both molecules proceeds via a similar pathway. A strong correlation was observed between the –NCO and –CN infrared band intensities and NO₂ conversion.     

A mild method for halofluorination of alkenes with ionic liquid EMIMF(HF)2.3

Halofluorination of alkene in the presence of N-halosuccinimide and ionic liquid, 3-ethyl-1-methyl-imidazorium oligo hydrogen fluoride (EMIMF(HF)_2.3), as a HF source was demonstrated. Various alkenes were converted into β-halo organofluorides in good yields and with high regioselectivity.     

Synthesis ofS-(Carboxymethyl)-d-cysteine by 3-chloro-d-alanine chloride-lyase ofPseudomonas putida CR 1-1

S-(Carboxymethyl)-d-cysteine, which is an important component of semisynthetic cephalosporin, MT-141, was enzymatically synthesized.S-(Ethoxy-carbonyl-methyl)-d-cystein was synthesized from 3-chloro-d-alanine and ethyl thioglycolate by the β-replacement reaction of 3-chloro-d-alanine chloride-lyase fromPseudomonas putida CR 1-1 and subsequently hydrolyzed by alkali. The synthesizedS-(carboxymethyl)-d-cysteine was isolated from a large scale reaction mixture and identified physicochemically. The reaction conditions for the synthesis ofS-(ethoxycarbonylmethyl)-d-cysteine were optimized using resting cells ofP. putida CR 1-1.