Surface melting technique of small diameter stainless steel pipe by means of yttrium aluminium garnet laser

A new method of surface melting by using a high power yttrium aluminium garnet laser was developed. This method is applicable to a long distance and narrow space, because of the good accessibility of the laser beam through optical fibre.A desensitization of sensitized type 304 stainless steel pipe was demonstrated by using this technique. A melted layer of thickness approximately 200 μm had a very finite solidification structure, which contained approximately 1.5% δ-ferrite. The average chemical composition of this layer was almost the same as that of type 304 stainless steel, and a band of 300 μm thickness under the melted layer underwent solution heat treatment (SHT).As a result of such surface melting, the melted layer exhibited superior resistance to intergranular stress corrosion cracking (IGSCC). Since the SHT layer is highly resistant to IGSCC generally, it may be possible to improve the IGSCC resistance of base metal to a comparatively deep extent (500 μm from the surface) by this technique.     

Progress in development and design of the neutral beam injector for JT-60SA

Neutral beam (NB) injectors for JT-60 Super Advanced (JT-60SA) have been designed and developed. Twelve positive-ion-based and one negative-ion-based NB injectors are allocated to inject 30 MW D⁰ beams in total for 100 s. Each of the positive-ion-based NB injector is designed to inject 1.7 MW for 100 s at 85 keV. A part of the power supplies and magnetic shield utilized on JT-60U are upgraded and reused on JT-60SA. To realize the negative-ion-based NB injector for JT-60SA where the injection of 500 keV, 10 MW D⁰ beams for 100 s is required, R&Ds of the negative ion source have been carried out. High-energy negative ion beams of 490–500 keV have been successfully produced at a beam current of 1–2.8 A through 20% of the total ion extraction area, by improving voltage holding capability of the ion source. This is the first demonstration of a high-current negative ion acceleration of >1 A to 500 keV. The design of the power supplies and the beamline is also in progress. The procurement of the acceleration power supply starts in 2010.     

Purification and cDNA cloning of porcine brain GDP-L-Fuc:N-acetyl-beta-D-glucosaminide alpha1-->6fucosyltransferase

GDP-L-Fuc:N-acetyl-beta-D-glucosaminide alpha1-->6fucosyltransferase (alpha1-6FucT; EC 2.4.1.68), which catalyzes the transfer of fucose from GDP-Fuc to N-linked type complex glycopeptides, was purified from a Triton X-100 extract of porcine brain microsomes. The purification procedures included sequential affinity chromatographies on GlcNAcbeta1-2Manalpha1-6(GlcNAcbeta1-2Manalpha1- 2)Manbeta1-4GlcNAcbet a1-4GlcNAc-Asn-Sepharose 4B and synthetic GDP-hexanolamine-Sepharose 4B columns. The enzyme was recovered in a 12% final yield with a 440, 000-fold increase in specific activity. SDS-polyacrylamide gel electrophoresis of the purified enzyme gave a major band corresponding to an apparent molecular mass of 58 kDa. The alpha1-6FucT has 575 amino acids and no putative N-glycosylation sites. The cDNA was cloned in to pSVK3 and was then transiently transfected into COS-1 cells. alpha1-6FucT activity was found to be high in the transfected cells, as compared with non- or mock-transfected cells. Northern blotting analyses of rat adult tissues showed that alpha1-6FucT was highly expressed in brain. No sequence homology was found with other previously cloned fucosyltransferases, but the enzyme appears to be a type II transmembrane protein like the other glycosyltransferases.     

Relationship between morphological diversity and AgNORs or cathepsin B expression in colorectal cancers

The biological characteristics associated with the morphological diversity of colorectal cancers were investigated to elucidate the causes of this diversity. We examined the proliferative and infiltrating activity of tumor cells, indicated by the mean number of Ag nucleolar organizer region associated proteins (NORs) per nucleus (MNA) and the immunohistochemical response to cathepsin B(CB), in various morphological types of early and advanced colorectal cancers. We examined 73 colorectal cancers obtained by endoscopic and surgical resection. MNA values for sessile and flat-elevated cancers were greater than the values for pedunculate, subpedunculate, and flat-or-depressed early cancers (sessile, P < 0.05). In advanced cancers invading the muscularis propria, protruding cancers showed significantly higher MNA values than small ulcerative cancers (P < 0.01). CB expression increased significantly with the progression of colorectal cancers (P < 0.01), but was not related to morphological diversity in early and advanced cancers. In both sessile and flat cancers, CB expression was higher in moderately differentiated than in well differentiated adenocarcinomas. These results indicate that, in colorectal cancers, protruding early cancers without stalks and protruding advanced cancers have higher proliferative activity than pedunculate or flat early cancers and small ulcerative advanced cancers, respectively, and that CB expression is not associated with morphological diversity, but with depth of invasion and histological differentiation.     

Platelet activating factor and tumor necrosis factor-alpha in bronchoalveolar lavage fluid of patients with ARDS

Platelet activating factor (PAF) and tumor necrosis factor alpha (TNF-alpha) were examined in the bronchoalveolar lavage fluid (BALF) of 21 ARDS patients to clarify the role of these factors in ARDS. Neutrophil percentages and albumin concentrations in the BALF of the ARDS group were markedly elevated compared with those in the control group (p < 0.01), showing a significant correlation (r = 0.596, p < 0.01). PAF was detected in 14 of 19 ARDS patients (237.5 +/- 86.0 pg/ml) and TNF-alpha was detected in 7 of 16 ARDS patients (24.9 +/- 13.6 pg/ml), whereas these factors were not detected in control subjects. Neither PAF nor TNF-alpha showed a significant correlation with neutrophil percentage, neutrophil number or albumin concentration. They do not seem to be contributing factors to the prognosis of ARDS patients. However the existence of PAF and TNF-alpha in the BALF of some ARDS patients suggests that they might play a role in the pathogenesis of ARDS.     

The measurement of the diffusion coefficient of U(VI) in aqueous uranyl sulfate solutions

The diffusion coefficients of U(VI) in aqueous uranyl solutions were determined between 293.5 and 311.0 K by comparing the limiting current densities between the copper electrodeposition and the electrolytic reduction of uranyl sulfate under the same hydrodynamic condition. The diffusion coefficients thus determined were almost constant despite the change in agitation speed of electrolyte solutions, which suggests the appropriateness of the method employed in this study. On the other hand, the diffusion coefficients of U(VI) showed a slightly decreasing trend with increase in uranyl sulfate concentration, but when total uranium concentration was kept constant the diffusion coefficient appeared to be almost constant. The activation energies of diffusion coefficients of U(VI) were found to be 21 to 22 kJ mol⁻¹ for the solution studied. KOJI SATO formerly Graduate Student, Department of Metallurgy, Kyoto University, Kyoto, Japan     

The leaching of chalcopyrite with ferric sulfate

The leaching kinetics of natural chalcopyrite crystals with ferric sulfate was studied. The morphology of the leached chalcopyrite and the electrochemical properties of chalcopyrite electrodes also were investigated. The leaching of chalcopyrite showed parabolic-like kinetics initially and then showed linear kinetics. In the initial stage, a dense sulfur layer formed on the chalcopyrite surface. The growth of the layer caused it to peel from the surface, leaving a rough surface. In the linear stage, no thick sulfur layer was observed. In this investigation, chalcopyrite leaching in the linear stage was principally studied. The apparent activation energy for chalcopyrite leaching was found to range from 76.8 to 87.7 kJ mol⁻¹, and this suggests that the leaching of chalcopyrite is chemically controlled. The leaching rate of chalcopyrite increases with an increase in Fe(SO₄)_1.5 concentration up to 0.1 mol dm⁻³, but a further increase of the Fe(SO₄)_1.5 concentration has little effect on the leaching rate. The dependency of the mixed potential upon Fe(SO₄)_1.5 concentration was found to be 79 mV decade⁻¹ from 0.01 mol dm⁻³ to 1 mol dm⁻³ Fe(SO₄)_1.5. Both the leaching rate and the mixed potential decreased with an increased FeSO₄ concentration. The anodic current of Fe(II) oxidation on the chalcopyrite surface in a sulfate medium was larger than that in a chloride medium.     

Thermodynamic studies of the V3S4-V5S8 system at temperatures from 650 to 800?C

Phase equilibria in the composition range between VS1.33 and VS_1.60 were studied by vary-ing the partial pressure of sulfur at 650, 700 and 750‡C. Phase separation in the V3S4 phase was observed at these temperatures in contrast to the results in the previous work at 800‡C. The separated phase was regarded as V₂S₃. The standard free energies of sul-furization from the stoichiometric V₃S₄ to the stoichiometric V₅S₈ at above temperatures have been calculated from the data of the equilibrium partial pressure of sulfur and each activity at which phase transition was caused. The standard enthalpy and the entropy changes of the above sulfurization reaction have been evaluated from the free energy data obtained.     

A high-resolution and high-stability charge-integration ADC forhigh-rate experiments

A charge-integration analog-to-digital converter (ADC) of 12-bit resolution was designed and built for the time-of-flight counters in the VENUS experiment at TRISTAN. The sample-and-hold process is done in the following way: outputs of a gated integrator were sampled before and after the integration gate timing; the voltage difference between the outputs was then recorded. By using this scheme, the output deviation caused by a short reset time is significantly reduced. The maximum deviation of the ADC counts is somewhat dependent on the duration for the discharge and the amount of integrated charge before the discharge. These effects were at most 3 counts and 2 counts, respectively. The integral nonlinearity was found to be within ±1 LSB (least-significant bit) and did not depend on the time duration for the discharge. The temperature coefficient of the gain was typically 100 p.p.m./°C. The temperature coefficient of the pedestal value was typically 0.15 counts/°C     

Analysis of irreversible circulation in reactor noise

A new parameter is proposed as a statistical variable of multi-dimensional reactor noise analysis. It indicates circulation in a space of state variables, while the well-known variance σ represents the spread of distribution of fluctuations. The pair of quantities σ and are minimum necessary integral indices to characterize any power spectral density and are convenient for data retrieval. The is less sensitive to the effect of low-cut filter than σ. The analysis of experimental data by using is demonstrated and compared with the results of theoretical treatment.