Benchmark experiment of large-angle scattering reaction cross section of iron at 14 MeV using two shadow bars – Comparison of experimental results with ENDF/B-VIII –

ABSTRACT

It is important to perform neutron transport simulations with accurate nuclear data in the neutronics design of a fusion reactor. However, absolute values of large-angle scattering cross sections vary among nuclear data libraries even for well-examined nuclide of iron. Benchmark experiments focusing on large-angle scattering cross sections were thus performed to confirm the correctness of nuclear data libraries. The series benchmark experiments were performed at a DT neutron source facility, OKTAVIAN of Osaka University, Japan, by the unique experimental system established by the authors’ group, which can extract only the contribution of large-angle scattering reactions. This system consists of two shadow bars, target plate (iron), and neutron detector (niobium). Two types of shadow bars were used and four irradiations were conducted for one experiment, so that contribution of room-return neutrons was effectively removed and only large-angle scattering neutrons were extracted from the measured four Nb reaction rates. The obtained experimental results were compared with calculations for five nuclear data libraries including JENDL-4.0, JEFF.-3.3, FENDL-3.1, ENDF/B- VII, and recently released ENDF/B-VIII. It was found from the comparison that ENDF/B-VIII showed the best result, though ENDF/B-VII showed overestimation and others are in large underestimation at 14 MeV.     

The significance of colocalization of plasminogen activator inhibitor-1 and vitronectin in hepatic fibrosis

BACKGROUND: We examined the relationships among vitronectin (VN), plasminogen activator inhibitor-1 (PAI-1), and transforming growth factor beta 1 (TGF-beta 1) in liver diseases to evaluate the presence of plasmin cascade in human hepatic fibrosis. METHODS: Blood and liver tissues were obtained from 57 patients with liver disease. Plasma VN, PAI-1 antigen, and PAI-1 activity levels were evaluated. Biopsied liver specimens were observed by light and electron microscopy after immunohistochemical staining. Morphometric analysis was performed on these specimens. RESULTS: Plasma VN and PAI-1 activity levels decreased significantly with the progression of hepatic fibrosis and were particularly marked in the liver cirrhosis group. Plasma PAI-1 antigen level increased significantly. The immunolocalization of the active form of TGF-beta became more intense with the progression of hepatic fibrosis, whereas that of the dual-stained positive areas of PAI-1 and VN (PAI-1.VN) decreased. There was a positive correlation between TGF-beta and PAI-1, whereas there was a negative correlation between TGF-beta and PAI-1.VN. Immunoelectron microscopy showed the localization of PAI-1-VN in the extracellular space around the sinusoidal cells or surface of aggregating platelets, TGF-beta mainly in Ito cells, and VN in hepatocytes near the focal necrotic area or fibrous septa. CONCLUSIONS: These findings suggest that VN and PAI-1 are related to the active form of TGF-beta and that it is possible that the plasmin cascade is present in the human liver.     

Three-dimensional motion of the upper cervical spine in rheumatoid arthritis

Rheumatoid arthritis frequently contributes to instability of the upper cervical spine. Rotational instability of the upper cervical spine was evaluated in rheumatoid arthritis patients using biplanar x-ray photogrammetry. Three-dimensional cervical motion and the instantaneous axis of rotation of the atlas relative to the axis were evaluated in normal and rheumatoid arthritis patients during axial rotation in the horizontal plane. Anterior atlantoaxial subluxation did not increase during axial head rotation in either the atlantoaxial subluxation or the vertical subluxation groups, while the instantaneous axes of rotation were distributed posteriorly in the dens in the RA-normal group, but were widely scattered in the atlantoaxial subluxation group.     

Advanced process device technology for 0.3-μm high-performancebipolar LSIs

A new method is developed for forming shallow emitter/bases, collectors, and graft bases suitable for high-performance 0.3-μm bipolar LSIs. Fabricated 0.5-μm U-SICOS (U-groove isolated sidewall base contact structure) transistors are 44 μm², and they have an isolation width of 2.0 μm, a minimum emitter width of 0.2 μm, a maximum cutoff frequency (f_T) of 50 GHz, and a minimum ECL gate delay time of 27 ps. The key points for fabricating high-performance 0.3-μm bipolar LSIs are the control of the graft base depth and the control of the interfacial layer between emitter poly-Si and single-Si. The importance of a tradeoff relation between f_T and base resistance is also discussed     

Evaluation technique of gate oxide damage

Gate oxide damage by plasma processing was evaluated using structures with various antenna lengths. The gate oxide damage by plasma processing was found to be monitored quantitatively by measuring the charge to breakdown, Q_BD. From the Q_BD measurements, we have confirmed that the degradation occurs during overetching, not in main etching. Plasma current was calculated from the decrease of Q_BD during the etching. The breakdown spot in the gate oxide was detected by photon emission and TEM. The LOCOS structure plays an important role for the degradation by plasma damage. In this paper, it is demonstrated that the Q_BD method is effective for realizing a highly reliable process against plasma damage     

Stabilization of SnO2 ultrafine particles by additives

In order to stabilize ultrafine particles of SnO₂ which is essential to obtain high gas sensitivity, a systematic investigation was undertaken regarding the stabilizing effects of 5 at% impregnated foreign additives, consisting of oxides or polyoxy compounds of 31 metals and 3 non-metals. The data of specific surface area, SA, as well as SnO₂ crystallite size, D, evaluated from X-ray diffraction showed that the additives could be classified into several groups according to the effectiveness. The most effective group, consisting of P-Ba, Sm, Ba, P, Mo, W, Ca, Sr, Cr and In, could keepD less than 10 nm even after calcination at 900°C, whereas pure SnO₂ underwent grain growth to haveD of 13 and 27 nm at 600 and 900°C, respectively. Electron microscopy revealed that neck sizes, X, between crystallites were fairly proportional toD(X/D = 0.80). A simple analysis of SA and D data based on a monosized sphere model suggested that each crystallite was coordinated with 3–4.5 neighbours through the necks. The existing state and stabilizing mechanism of additives are discussed in conjunction with the electrical resistance of porously sintered elements.     

Expression of fibrogenic cytokines in desmoplastic malignant melanoma

OBJECTIVE: Research has confirmed substantial links between OCD and AN. Not only are there psychopathological similarities between the two syndromes, but a marked neurochemical correspondence. Extensive exercising is a common feature of AN and also has relevance in its links with OCD. There is evidence from the exercise-induced weight-loss syndrome in animals that exercise and caloric restriction, in combination, tend to increase serotonergic activity in a synergistic manner. This syndrome has been proposed as a valid model of OCD as well as for AN. To date, little research has directly tested this theory in the human condition. METHOD: Fifty-three AN patients were categorized as high-level exercisers (N = 22) or moderate/nonexercisers (N = 31) based on the frequency of their physical activity over the year before assessment. RESULTS: Exercisers scored significantly higher on a measure of OC personality characteristics, OC symptomatology, and perfectionism--a personality factor associated with the development of Obsessive-Compulsive Personality Disorder. On the other hand, there were no group differences on other salient eating disorder characteristics such as body esteem, self-esteem, or weight preoccupation. There were also no differences in degree of emaciation as indicated by Body Mass Index. CONCLUSIONS: Findings suggest that among AN patients obsessional personality characteristics are linked to high-level exercising, and that exercising is associated with a greater degree of OC symptomatology. Results are discussed in the context of current theories of AN, OCD, and some biological mechanisms.     

In-process evaluation of grit protrusion feature for fine diamond grinding wheel by means of electro-contact discharge dressing

This paper introduces a new in-process evaluation method for grit protrusion feature on wheel surface by monitoring discharge current trace during electro-contact discharge (ECD) dressing of metal-bonded fine diamond grinding wheel. First an impulse discharge machining experiment was carried out to investigate the correlation between metal bond removal and discharge parameters, namely discharge current I_e and discharge pulse duration τ_e. Then ECD dressing experiment for #600 diamond grinding wheel was conduced to analyses the quantitative effect of the discharge parameters (I_e and τ_e), derived from discharge current trace between wheel and dresser (electrode), on grit protrusion feature of wheel surface. The result shows that the grit protrusion feature is sensitive to the discharge parameters (I_e and τ_e) with reference to mean diamond grit size d_gm. Further, the discharge parameters (I_e and τ_e) in ECD dressing should conform to the discharge variables’ requirement of , by which the grit protrusion feature may be evaluated and the dressing process variables may be determined. Finally, the in-process evaluation method was successfully applied to ECD dressing of #1500 diamond grinding wheel for valid grinding of hard-brittle materials.     

金属结合剂#600金刚石砂轮的接触放电修锐实验研究

针对微细金刚石磨粒很难从金属结合剂砂轮的胎体中出刃的问题，开发出一种新修锐方法一接触放电修锐、它采用一种旋转复合电极修整轮与砂轮接触磨削，在金属结合剂胎体与电极间产生微小的脉冲放电，逐渐去除砂轮的金属结合剂，使微细金刚石在砂轮工作表面出刃，达到精密修锐的目的。通过对金属结合剂#600金刚石砂轮进行修锐实验，研究其有效性、修锐条件和实际应用。实验表明，该修锐方法不仅不损伤微细金刚石磨粒出刃刃角，而且还可以消除磨粒周围的结合剂尾状物，产生较好的容屑空间。磨削光学玻璃(BK10)的试验结果显示它比机械修锐能够更好地提高磨削表面质量，Ra达到0．12μm。