Isotachophoretic analysis of surfactants

The qualitative and quantitative determination of anionic surfactants (sodium and lithium alkylsulfate, sodium dodecylbenzenesulfonate, sodium di-2-ethylhexyl sulfosuccinate, sodium and lithium perfluoroalkylcarboxylate, and lithium perfluorooctanesulfonate) were investigated by a capillary tube isotachophoresis using a potential gradient detector. The leading electrolyte solution was the mixture of acetonitrile and aqueous solution of histidine buffer containing calcium chloride. The terminating electrolyte solution was the aqueous solution of sodium octanoate. These electrolytes were effective for the analysis of the mixtures of strongly acidic surfactants.     

Solidification of Municipal Solid Waste Incineration Fly Ash with Cement and Its Leaching Behaviors of Heavy Metals

The solidifying qffect of cement addition on municipal solid waste incineration fly ash ( MSWFA for short, collected from the gas exhaust system of MSW incinerator), the interaction of MSWFA with cement and water and the leaching of heavy metals from cement-solidified MSWFA are investigated. The main results show that : ( 1 ) when MSWFA is mixed with cement and water, 112 evolution, the formation and volume expansion of AFt will take place, the volume expansion can be reduced by ground rice husk ash addition ; (2) heavy metals do leach from cement-solidified MSWFA and at lower pH more leaching will occur; (3) compared with cement - so-lidified fly ash, the leachate of solidified MSWFA is with higher heavy metal contents ; (4) with the increment of cement addition leached heavy metals are decreased ; and (5) concentrations of Zn , Mn , Cu and Cd in all the leachates can meet the relevant Standards of Japan, but as the regulations for soil and groundwater protection of Japan are concerned, precautions against the leaching of Pb , Cl^- and Cr^6 and so on are needed.     

Characteristics of Linear Synchronous Motor Drive Cycloconverter for Maglev Vehicle ML-500 at Miyazaki Test Track

Maglev vehicle ML-500 in Japan attained a speed of 517 km/h on December 21, 1979. The linear synchronous motor (LSM) drive cycloconverter fabricated and submitted to the track test has a capacity of approximately 12 000 kVA in a continuously variable frequency range of 0-34 Hz with a sinusoidal current waveform. The current can be arbitrarily controlled in a range of 200-1300 A. Despite the rigorous power conversion and control, excellent current control characteristics were obtained: less than 4 percent in deviation of current peak value, about 4 ° in leading phase deviation and approximately 1.2 ms in zero current interval. Some observations about the LSM driving system are made, and an outline of the design and the data obtained from the super-high-speed running tests on Miyazaki test track are given.     

Intravascular ultrasound findings after successful primary angioplasty for acute myocardial infarction: predictors of abrupt occlusion

OBJECTIVES: This study sought to evaluate the intravascular structure as depicted by intravascular ultrasound after successful primary angioplasty (i.e., without thrombolytic therapy) for acute myocardial infarction and to investigate the related predictors of acute coronary occlusion. BACKGROUND: The usefulness of primary angioplasty for acute myocardial infarction is still limited by early reocclusion. There are few data regarding the intravascular ultrasound findings after primary angioplasty. METHODS: Intravascular ultrasound was performed in 27 patients after successful primary angioplasty. Repeat coronary angiography was performed 15 min later, on the following day and 1 month after angioplasty. RESULTS: Abrupt occlusion occurred in 8 of 27 patients. Angiographic variables in patients with versus those without abrupt occlusion were not significantly different. Intravascular ultrasound disclosed a significantly smaller lumen area ([mean +/- SD] 2.49 +/- 0.72 vs. 5.06 +/- 1.52 mm2, p < 0.001) and a significantly greater percent plaque area (80.5 +/- 9.1% vs. 63.7 +/- 7.8%, p < 0.001) in patients with abrupt occlusion. There was no significant difference in external elastic membrane cross-sectional area. We classified the ultrasound appearance of the intravascular structure as smooth, irregular or filled. Abrupt occlusion occurred in none of 6 patients with a smooth intravascular structure, 24% of 17 patients with an irregular structure and in all 4 with a filled structure (p < 0.05). In the latter group, the lumen was filled with bright speckled or low echogenic material, although angiography revealed excellent coronary dilation in all these arteries. CONCLUSIONS: Intravascular ultrasound revealed a narrow lumen in coronary arteries showing abrupt occlusion after successful primary angioplasty, even though angiography disclosed successful dilation. Arteries with a lumen filled with bright speckled or low echogenic material frequently develop abrupt occlusion.     

Steric hindrance by 2 amino acid residues determines the substrate specificity of isomaltase from Saccharomyces cerevisiae

The structures of the E277A isomaltase mutant from Saccharomyces cerevisiae in complex with isomaltose or maltose were determined at resolutions of 1.80 and 1.40 Å, respectively. The root mean square deviations between the corresponding main-chain atoms of free isomaltase and the E277Α-isomaltose complex structures and those of free isomaltase and the E277A-maltose complex structures were found to be 0.131 Å and 0.083 Å, respectively. Thus, the amino acid substitution and ligand binding do not affect the overall structure of isomaltase. In the E277A-isomaltose structure, the bound isomaltose was readily identified by electron densities in the active site pocket; however, the reducing end of maltose was not observed in the E277A-maltose structure. The superposition of maltose onto the E277A-maltose structure revealed that the reducing end of maltose cannot bind to the subsite + 1 due to the steric hindrance from Val216 and Gln279. The amino acid sequence comparisons with α-glucosidases showed that a bulky hydrophobic amino acid residue is conserved at the position of Val216 in α-1,6-glucosidic linkage hydrolyzing enzymes. Similarly, a bulky amino acid residue is conserved at the position of Gln279 in α-1,6-glucosidic linkage-only hydrolyzing α-glucosidases. Ala, Gly, or Asn residues were located at the position of α-1,4-glucosidic linkage hydrolyzing α-glucosidases. Two isomaltase mutant enzymes – V216T and Q279A – hydrolyzed maltose. Thus, the amino acid residues at these positions may be largely responsible for determining the substrate specificity of α-glucosidases.     

Four-index integral transformation exploiting symmetry

We present a Fortran implementation of four-index integral transformation in the LCAO-MO (linear combination of atomic orbitals-molecular orbitals) framework that exploits symmetry. Electron correlation calculations, such as configuration interaction (CI) calculations, usually require electron repulsion integrals to be transformed to a molecular orbital basis from a basis using atomic orbitals. In large molecular systems it is vital to exploit the sparsity of integrals in making this transformation. By exploiting symmetry, the sparsity of integrals is fully utilized, the size of intermediate file is minimized, and the computational cost is reduced. The present algorithm is simple and can readily be added to existing quantum chemistry program packages.

Program summary

Title of program: SYM4TR (symmetry adapted 4-index integral transformation)Catalogue identifier: ADUWProgram summary URL:http://cpc.cs.qub.ac.uk/summaries/ADUWProgram obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandComputers: IBM/AIX, HP Alpha server/Tru64, PC's/LinuxProgram language used: Fortran 95Number of lines in distributed program, including test data, etc.: 4519No. of bytes in distributed program, including test data, etc.: 32 095Distributed format: tar gzip fileNature of physical problem: Molecular orbital calculations including electron correlation effects usually require electron repulsion integrals to be transformed from an atomic orbital (AO) basis to a molecular orbital (MO) basis. By exploiting the sparsity of molecular integrals, the computational cost and memory needed for the transformation are minimized.Method of solution: The sparsity of molecular integrals is exploited. The program treats only nonzero integrals. The length of running indices in DO loops is reduced using the block-diagonal form of the MO coefficient matrix. In the present program, the point group is limited to D_2h and its subgroups.     

浸没式光刻的优势和可行性

浸没式光刻通过高折射率的液体充入透镜底部和片子之间的空间使光学系统的数值孔径具有显著的优势。在193nm曝光系统中,水(折射率为1.44)被选作最佳的浸入液体。通过成像模拟,现已证明ArF穴193nm雪浸没式光刻(NA=1.05～1.23)与F2穴157nm雪干法穴NA=0.85～0.93雪光刻具有几乎相同的成像性能。结合流体力学和热模拟结果,讨论了ArF浸没式曝光设备的优势和可行性。     

Surface chemistry of galvanized steel sheets relevant to adhesion performance

A review is presented on the recent development of surface treatment technologies for hot-dip galvanized steels relevant to adhesion of organic coatings. Applications of surface analytical techniques have elucidated that the surface layers of the nanometer scale dramatically govern the adhesion performance of painting or adhesive bonding. Surface enrichment of aluminium in the zinc layer deteriorates paint adhesion due to the reduction in phosphatability on the galvanized steel sheets and decreases the adhesive strength of the epoxy/dicyandiamide-bonded sheets due to the loss of acid-base interaction at the adhesive-substrate interface. In addition, the co-segregation of Al and Pb into the surface layer is responsible for the intergranular corrosion of zinc and facilitates the formation of a weak boundary layer, resulting in poor bond durability in a wet atmosphere. Improved adhesion performance has been established by developing new technologies that reduce the surface enrichment of minor elements or impurities in the zinc layer on the galvanizing line or that adopt a surface conditioning process prior to pretreatment in subsequent coil coating lines.