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To explore changes in left ventricular (LV) function and the relationship of these changes with myocardial blood flow (MBF) evaluated byFifty-two consecutive patients with suspected CAD, who underwentMRI showed that the LV end-diastolic volume, LV end-systolic volume, and LV ejection fraction (LVEF) remained unchanged during vasodilator stress in all patients (n=52) as well as in the patients with CFR of2 (n=27), stress MBF of1.3 ml/g/min (n=28), abnormal myocardial perfusion (n=30), and more than one diseased vessel (n=46). In only four patients, the LVEF measured by MRI decreased by5% during vasodilator stress. In these four patients, CFR was lower (1.57 ± 0.12 versus 2.18 ± 0.86, p0.01) and the number of diseased vessels was higher (2.75 ± 0.50 versus 1.48 ± 0.92, p0.01) than in patients without post-stress LV dysfunction.The LV volume and systolic function evaluated by cardiac MRI remained unchanged during vasodilator stress; however, LV dysfunction during vasodilator stress may occur in patients with severe CAD.

Summary This study was conducted to test the replacement of fishmeal (FM) with a combination of corn gluten meal (CGM)-soybean meal (SBM) (at a ratio of 58 : 42, respectively) fortified with lysine, taurine and monocalcium phosphate (MCP) in turbot (Scophthalmus maximus) diets. FM as the main protein source in the control diet (FM100) was replaced in 15% decrements while increasing the combination of replacement material: 85% FM (FM85), 70% FM (FM70), 55% FM (FM55) and 40% FM (FM40). The diets were fed to triplicate groups (n = 25 per group) for 9 weeks (water temperature, dissolved oxygen, pH and salinity of 18.59 ± 0.06°C, 7.32 ± 0.02 mg L−1, 7.73 ± 0.01 and 8.46 ± 0.04 g L−1, respectively). Initial weight of fish was 286.1 ± 0.1 g. At the end of the experiment, growth, feed and nutrient utilization performance of fish fed FM85 and FM70 were similar to FM100, but a further increase in plant protein led to a significant reduction of these parameters. Whole body, fillet, viscera and liver nutrient compositions were not affected significantly; however, whole body lipid levels were significantly lower in fish on FM55 and FM40 than those on FM100. The fish in–fish out ratio in the diets decreased from 2.12 in FM100 to 1.00 in FM40. The results suggest that the FM level could be reduced by 30% with a combined use of CGM-SBM supplemented with lysine, taurine and MCP.

This paper describes the development of a self-coaching system to improve driving behavior by allowing drivers to review a record of their own driving activity. By employing stochastic driver-behavior modeling, the proposed system is able to detect a wide range of potentially hazardous situations, which conventional event data recorders are not able to capture, including those involving latent risks, of which drivers themselves are unaware. By utilizing these automatically detected hazardous situations, our web-based system offers a user-friendly interface for drivers to navigate and review each hazardous situation in detail (e.g., driving scenes are categorized into different types of hazardous situations and are displayed with corresponding multimodal driving signals). Furthermore, the system provides feedback on each risky driving behavior and suggests how users can safely respond to such situations. The proposed system establishes a cooperative relationship between the driver, the vehicle, and the driving environment, leading to the development of the next generation of safety systems and paving the way for an alternative form of driving education that could further reduce the number of fatal accidents. The system's potential benefits are demonstrated through preliminary extensive evaluation of an on-road experiment, showing that safe-driving behavior can be significantly improved when drivers use the proposed system.

The radiation-induced releasing of the liquid-core of the microcapsules was improved using H 2 O 2, which produced O 2 generation of H 2 O 2 after irradiation. Further, we tested whether these microcapsules enhanced the antitumor effects and decreased the adverse effects in vivo in C3He / J mice. The capsules were produced by spraying a mixture of 3.0% hyaluronic acid, 2.0% alginate, 3.0% H 2 O 2, and 0.3 mmol of carboplatin on a mixture of 0.3 mol FeCl 2 and 0.15 mol CaCl 2. The microcapsules were subcutaneously injected into MM46 tumors that had been inoculated in the left hind legs of C3He / J mice. The radiotherapy comprised tumor irradiation with 10 Gy or 20 Gy 60 Co . The antitumor effect of the microcapsules was tested by measuring tumor size and monitoring tumor growth. Three types of adverse effects were considered: fuzzy hair, loss of body weight, and death. The size of the capsule size was 23 ± 2.4 µ m ɸ and that of the liquid core, 20.2 ± 2.2 µ m ɸ. The injected microcapsules localized drugs around the tumor. The production of O 2 by radiation increased the release of carboplatin from the microcapsules. The antitumor effects of radiation, carboplatin, and released oxygen were synergistic. Localization of the carboplatin decreased its adverse effects. However, the H 2 O 2 caused ulceration of the skin in the treated area. The use of our microcapsules enhanced the antitumor effects and decreased the adverse effects of carboplatin. However, the skin-ulceration caused by H 2 O 2 must be considered before these microcapsules can be used clinically.

In TIARA facility of Japan Atomic Energy Agency (JAEA) Takasaki, we have produced three-dimensional micro/nano-structures with high aspect ratio using cross linking process based on negative resist such as SU-8 by a technique of mask less ion beam lithography. By bombarding high energy heavy ions such as 450 MeV Xe 23+ to SU-8, on the other hand, it appeared that a nanowire could be produced just with a single ion hitting. Then we tried to produce nanowires, of which both ends were fixed in the three-dimensional structure. This paper shows a preliminary experiment for this purpose using a combination of 15 MeV Ni 4+ ion microbeam patterning and the 450 MeV 129 Xe 23+ hitting on SU-8.

An ion-beam-lithography technique has been progressed in the microbeam systems at Japan Atomic Energy Agency (JAEA) Takasaki. In order to obtain a high-precision measure for microbeam size estimation with a high precision, we applied this technique combined with the electroplating process to make a Ni relief pattern as a resolution standard used in secondary electron imaging. As a result, the smallest beam size could be recorded. The scattering of ions in the materials influenced the spatial resolution and this is also discussed.

This study was undertaken to elucidate physiological properties of fucoidan extracted from Cladosiphon okamuranus TOKITA (C. okamuranus) and Fucus vesiculosus (F.vesilurosus). According to the data on MTT assay and TUNEL staining, F. vesiculosus possessed more anti-proliferate activity than C. okamuranus through apoptosis induction. We determined the metal contents of fucoidan to evaluate the relevance of metal elements in its biological effects. Al , Fe and Zn levels were significantly increased in F. vesiculosus than in C. okamuranus. The intracellular changes of metal elements following the administration of fucoidan was analyzed by in-air micro-PIXE in TRL1215 cells (normal rat liver cell line). At 24 h after 5-bromo-2'-deoxyuridine ( BrdU ) dosing, TRL1215 cells were treated with 1.0 mg/mL of each fucoidan for 9 h. The X-ray spectra showed that F. vesiculosus-treated cells markedly increased the yield of aluminum ( Al ) compared to those of C. okamuranus -treated cells and the control. In F. vesiculosus -treated cells, the focal accumulation of Br was spatially correlated with Al map, suggesting that Al was localized within the nucleus. These findings suggest that F. vesiculosus fucoidan increases the accumulations of Al in rat hepatocytes, which may participate in anti-proliferate activity of this fucoidan.

This study was undertaken to elucidate the intracellular changes of metal elements after the administration of fucoidan extracted from Cladosiphon okamuranus. TRL1215 cells (normal rat liver cell line) were treated with 0, 0.1, or 1.0 mg/ml fucoidan and incubated in 5% CO2 at 37 degrees C. The cellular levels of Mg, Al, Fe, and Zn were significantly increased in the 1.0 mg/ml fucoidan-treated cells compared to those of the 0.1 mg/ml fucoidan-treated cells and the control. Next, TRL1215 cells were cultured on Mylar film overnight. At 24 h after 5-bromo-2'-deoxyuridine dosing, 0, 0.1, or 1.0 mg/ml fucoidan was treated for 9 h. The cellular distribution of elements was analyzed using in-air micro-micro-particle induced X-ray emission. The X-ray spectra showed that yields of Al, Mg, and Zn were high in order of the 1.0 mg/ml fucoidan-treated sample, the 0.1 mg/ml fucoidan-treated sample, and the control. Fe yield was mildly increased by fucoidan administration. In fucoidan-treated cells, the focal accumulation of Br was correlated spatially with phosphorous-rich region, suggesting that Br was localized within the nucleus. Al distribution provided a spatial association with Br map. These data suggest that fucoidan increases the accumulations of Al, Mg, Fe, and Zn in normal rat hepatocytes, and fucoidan-binding Al is postulated to be transferred into the nucleus.

A high energy focused ion beam with sub-μm spatial resolution was used to produce isolated nano-wires which were planted on the substrate. Each charged particle penetrating into a polymer thin film gave a corresponding nano-wire, whose length reflected precisely the thickness of the target film. Based on the tight connection of one end of each nano-wire on the substrate, the focused ion beam achieved position selective nano-wire or nano-wire bundle formation on the substrate. The ion beam, with the small spot size (Φ) < 500 nm, was electrostatically controlled to irradiate the polymer thin films, leading to the patterns of nano-wire bundles with high spatial resolution

Structural and optical properties of silica glass induced by ion microbeam irradiation were studied using micro- photoluminescence (μ-PL) spectroscopy and atomic force microscopy (AFM). Ion microbeam irradiation was performed using microbeam lines of 3-MV single-ended or tandem accelerators with various ion species including H+, He+, B3+, C4+, N4+, O4+, and Si5+ at energies of 1.7 to 18 MeV. The beam was focused to about 1 μm and was scanned over the surface of high-purity silica glass with fluences of 1013 to 1018 ions/cm2. The μ-PL spectrum in microbeam-irradiated silica shows two peaks at 540 and 650 nm. The mapping of the two PL bands reveals the distribution of defects induced along the track of ions. The compaction was observed in the form of groove at the surface of silica glass by AFM. The depth of the surface groove increases with increasing ion fluence and saturates at about several hundreds to 900 nm, depending on irradiated ion species. The mechanisms of structural and optical modifications of silica glass are can be understood in terms of energy loss due to electronic stopping and nuclear stopping powers. Refractive index changes with an order of 10– 4 to 10− 2 were estimated by a Lorentz–Lorenz relationship from the compaction. Technological implications of these results are also to be discussed.

This study undertook the analysis of tissue cadmium (Cd) distribution using in-air micro-particle-induced X-ray emission (PIXE) and the examination of the involvement of metal ions in parenteral Cd toxicity. A mouse was injected intraperitoneally with 3 mg/kg body weight of CdCl2 thrice weekly. After 27 wk, the liver and kidney were excised and fixed in 10% formalin solution for 4 h and then embedded in paraffin. Thin paraffin sections were used to analyze trace elements with in-air micro-PIXE and to examine metallothionein protein and histological changes. Cd distribution was determined by micro-PIXE in the liver and renal cortex of the Cd-exposed mouse, and the net Cd count was higher in the liver than in the renal cortex. The net iron (Fe) count was higher in the liver of the Cd-exposed mouse compared to the control, and an opposite tendency was observed in the renal cortex. Wide cellular Cd distribution was demonstrated in the liver and renal cortex of the chronic Cd-exposed mouse compared to the control. Metallothionein staining was increased by chronic exposure to Cd both in the liver and kidney, and nephrotoxicity was more apparent than hepatotoxicity. The modification of tissue Fe and calcium distribution by an intraperitoneal injection of Cd might be involved in Cd-induced toxicity.

High-purity silica glass was irradiated by a focused 15-MeV O 4+ microbeam with diameter of 1 μm up to a fluence of 1.0 × 10 14 ions/cm 2 . Spatial distribution of irradiation effects by the O 4+ microbeam on silica glass was investigated by optical microscopy, microphotoluminescence (PL)/Raman spectroscopy and atomic force microscopy (AFM). Distribution of refractive index change and defect formation was visualized by optical microscopy and PL mapping, indicating the structural changes of silica glass along the ion track up to the depth of 10 μm. In addition, we observed deformed side surface with a groove by AFM along the track suggesting the internal compaction in silica glass. This is accompanied by increased threefold rings of SiO 2 network detected by Raman scattering. We also discuss technological implications of these results on the applications of microbeam irradiation effects to the fabrication of microoptical elements.

Heavy element-sorbing montmorillonite and apatite were analyzed by micro-PIXE to examine its applicability to quantitative analysis of the heavy elements sorbed on these minerals. It was found that the sorbed heavy elements can be evaluated quantitatively using the linear correlation between the following two factors: (a) the concentration of the sorbed element in the mineral and (b) the ratio of the net peak area of characteristic X-ray from the sorbed element and to that from the matrix cation of the mineral. Mineralogical features of the tested minerals including heterogeneity of elemental distribution in the depth direction of the mineral hardly affected the results.

Distributions of structural and refractive index changes of silica irradiated by H + microbeam were studied by optical and atomic force microscopes (AFM). The AFM measurements on the microbeam irradiated area show the formation of a groove on the surface. In addition, a cross sectional observation on the surface parallel to the incident plane reveals surface deformation along the ion tracks, which is deepest at the projected range of ions. Taking into account the possible structural changes of silica induced by energy deposition calculated by TRIM, the measured topological changes at the front and side surfaces result from internal compaction of silica glass. Refractive index changes were estimated from the Lorentz–Lorenz relationship using the distribution of the internal compaction estimated by the AFM measurements.

To study the interactions between the induction of radiation-induced apoptosis and trace elements kinetics, human leukemia cells were irradiated in vitro by 60 Co γ rays, after which the cells were evaluated for the detection of apoptosis and trace element (Fe, Ca, Zn) imaging was carried out. The frequency of apoptosis, i.e. the number of apoptotic bodies per 100 nuclei, was obtained by microscopic assay using TUNEL staining at 400× magnification. The trace element distribution in the cell was determined by micro-PIXE using 2 MeV proton beams. In the early phase of apoptosis, the maximum level of Fe accumulation was observed in the cell stroma. In the mid to end phase, Fe accumulation was diminished, and instead, Ca accumulation increased and Zn decreased in the nucleus. There appear to be two steps for the development of apoptosis: (1) the signaling from cell stroma to nucleus by Fe or an Fe-containing enzyme; and (2) the degeneration of the nucleus by Ca-dependent enzyme, and release of Zn from digested nucleus. Those strong accumulations may be new markers for apoptosis.

We evaluated structural changes in silica glass induced by ion microbeam using microscopic photoluminescence (PL) and Raman scattering measurements. Microbeams (1.7 MeV H+) were scanned over the sharp right-edges of the silica substrates with a fluence of 1×1017 cm−2, then two PL bands of silica at 540 and 650 nm were observed at the irradiated region. The PL bands show different lateral and depth distributions. The distribution of the 540 nm PL is in good agreement with that of the refractive index changed region. The lateral distribution of the 650 nm band is broader by 1.5 times than those of the 540 nm PL and the refractive index changed region. The microscopic Raman scattering measurements show an increased intensity of 606 cm−1 peak associated with compaction at the microbeam irradiated regions.

We developed a novel technique to obtain 3D-imaging of elemental distribution based on multi-angle RBS measurement and micro-beam scanning. Since cross-sections of RBS are too small to obtain 3D-imaging, it is necessary to measure scattered particles with large solid angle detectors. Hence, the RBS profiles from each scattering angle are superposed and a true depth profile cannot be obtained. Recently, a large solid angle X-ray detector array consisting of 45 detector elements was installed at the TIARA facility of Japan Energy Research Institute. Each detector element measures X-rays as well as scattered particles. For this utilization, we introduced a technique to superpose RBS profiles and applied it to the surface analysis of an ant’s head.

Microhabitats of bacteria (biomat) and lower plants, such as lichen and mosses, are known to accumulate hazardous elements. Since the concentration of hazardous elements in the environment is quite low, we have applied the in-air μ-PIXE (particle induced X-ray emission) system developed in the TIARA facility of JAERI, which has low concentration detection limit of ppm, to measure As, one of the hazardous elements, distributions in biomat, lichen and mosses observed around an abandoned As mine site in Gunma, Japan to elucidate the applicability of these biomat and lower plants as bio-indicators of As. Spatial distributions of As, Fe, Si and S in all biomat, lichen and moss collected within 3 m from the mine entrance indicate that As is localized, and is associated with silicate and Fe-containing compounds. In addition, the intensity ratio of peak area for As to Fe in μ-PIXE spectrum of the moss collected from the concrete wall at 3 m downstream of the mine water discharge position is different from those of the lower plants on the rock near the closed entrance, but is the same as that of biomat formed at the mine water discharge position. This indicates that As trapped by the moss on the concrete wall probably has the same origin as the biomat. It is concluded that application of μ-PIXE analysis to the measurement of As in the lower plants and biomat gives not only the distribution of the hazardous element of As, but also the information of the origin.

Radiation effects induced by ion microbeam were studied by a confocal microspectroscopy and an atomic force microscopy (AFM). We investigate two significant radiation effects, defect generation and compaction, which were ascribed to electronic (Eelec) and nuclear stopping powers (Enucl), respectively. Photoluminescence mapping of nonbridging oxygen hole centers at 650 nm reveals the defect formation along the tracks of ions. The surface deformation measured by AFM depends on the width of irradiated by microbeam. Confinement effects from the interface of irradiated and nonirradiated regions are taken into account for the understanding of the correlation between the surface deformations and internal compactions.

Alkylene groups incorporated porous silica films were prepared by using hydrolysis and condensation of BIS (Triethoxysilyl) Ethelene (BTE). BTE and H 2 O containing HCl as a catalyst were mixed with organic solvent, 2-Methylpentane-2,4-diol (MPD). FT-IR peaks due to MPD were not observed but Si–C 2 H 4 –Si related peaks were still observed in the film even after 450°C vacuum annealing. Electric characteristics were evaluated with an MOS structure. K value does not depend on the annealing temperature below 400°C; however, it was reduced down to 1.9 at 450°C.

Micro-PIXE is capable of providing spatial distributions of elements in the micro-meter scale and its application to biology is useful to elucidate the cellular metabolism. Since, in this method, a sample target is usually irradiated with proton or α-particle beams in vacuum, beam heating results in evaporation of volatile elements and shrinking of the sample. In order to avoid these side effects, we previously developed a technique of in-air micro-PIXE analysis for samples of cultured cells. In addition to these, analysis of exposed tissue samples from living subjects is highly desirable in biological and medical research. Here, we describe a technique of in-air micro-PIXE analysis of such tissue samples. The target samples of exposed tissue slices from a Donryu rat, in which a tumor had been transplanted, were analyzed with proton micro-beams of 2.6 MeV. We report that the shape of cells and the distribution of volatile elements in the tissue sample remain uncharged when using a target preparation based on a freeze-drying method.

application/pdf, A probe wave system was constructed for studying the excitation of the Alfvén ion cyclotron (AIC) modes in the anchor cell of the GAMMA 10 tandem mirror. In the central cell, the AIC modes are spontaneously excited as axial eigenmodes due to the strong temperature anisotropy. In the anchor cell, the AIC modes were not observed though the anisotropy is the same as in the central cell. The axial profiles of the magnetic field strength and plasma parameters in the anchor cell are different from those in the central cell. Eigenmodes are excited externally in the AIC frequency range by injecting probe waves. This suggests the AIC modes are unstable in the anchor cell and grow to the detectable level when boundary conditions are realized.

In the GAMMA10 tandem mirror, a strong ion cyclotron range of frequency heating is performed. As a result of the heating, the Alfven ion cyclotron (AIC) modes are spontaneously excited due to the strong temperature anisotropy. The AIC modes in the GAMMA10 are excited as the axial eigenmodes and detected at the whole of the device. In the recent experiments, the clear standing wave structure is observed with the magnetic probe measurements. Characteristics of the AIC modes and the measurement of the axial profile are presented.

Out of plane measurements of the angular correlations for the 12C(e, e(')n) reaction have been performed for the first time in the giant resonance region. The cross sections were directly separated into the longitudinal and transverse, longitudinal-transverse, and transverse-transverse components. The cross section at the peak of the giant resonance ( omega = 22.5 MeV) has been found to be almost all longitudinal. It was reproduced by the multipole expansion with E0 and E2 components besides E1. The longitudinal-transverse component might have a maximum around 24 MeV. The transverse-transverse component is very small over the giant resonance.

Glycinebetaine is synthesized in plants by the two-step oxidation of choline, with betaine aldehyde as the intermediate. The reactions are catalyzed by choline mono-oxygenase and betaine aldehyde dehydrogenase. Rice plants, which do not accumulate glycinebetaine, possess a gene encoding betaine aldehyde dehydrogenase, whose activity is detectable at low levels. To evaluate the compatibility in rice of glycinebetaine on growth and tolerance to salt, cold and heat, we produced transgenic rice plants by introduction of a cDNA for betaine aldehyde dehydrogenase of barley, which is localized in peroxisomes unlike the chloroplast-specific localization of betaine aldehyde dehydrogenase in spinach and sugar beet. The transgenic rice plants converted high levels of exogenously applied betaine aldehyde (up to 10 mol m 3 ) to glycinebetaine more efficiently than did wild-type plants. The elevated level of glycinebetaine in transgenic plants conferred significant tolerance to salt, cold and heat stress. However, very high levels of glycinebetaine, resulting from conversion of applied betaine aldehyde to glycinebetaine or from exogenous application, inhibited increases in length of rice plants but not increases in dry weight. Our results suggested that the benefits of accumulation of glycinebetaine by rice plants might be considerable under high light conditions.

Single Event Effects (SEEs) triggered by energetic heavy ions traversing a sensitive parts of electric devices have been studied using high-energy heavy ion microbeams connected with Transient Ion Beam Induced Current (TIBIC) measuring system at the Japan Atomic Energy Agency (JAEA) Takasaki Ion Accelerators for Advanced Radiation Applications (TIARA) facility. In the TIBIC system, SEE for semiconductor device, that is fast charge collection, has been observed in timescales of the order of picoseconds. In this paper, we show successful demonstration of the performance of the system, in which clear images of TIBIC map have been observed for Si pin photodiodes irradiated by 260 MeV 20 Ne 7+ and also by 520 MeV 40 Ar 14+ microbeams.

Aiming to develop a compact and inexpensive in situ cleaning device, an experiment on the removal of hydrocarbon by oxygen and hydrogen plasmas was carried out. The plasmas were produced using a 60 MHz RF-discharge. The oxygen plasma had an electron temperature Te=5 eV and an ion density was 2×10 10 cm -3 with a pressure of 2.3 m Torr and an RF power of 130 W. Observations showed a decrease in the hydrocarbon pressure by about two orders of magnitude after irradiation by the oxygen plasma for about 1 h, though much of the decrease occurred in the first few minutes.

The background due to the Compton scattering of γ-rays in a Si ( Li ) X-ray detector was measured with the coincidence system which consists of a Si ( Li ) X-ray detector and NaI ( Tl ) scintillation detector. The Si ( Li ) X-ray detector is a through type to detect γ-rays of the Compton scattering into the forward direction. The energy spectra of the Si ( Li ) detector were measured for γ-rays of 662 keV from a 137 Cs source. The contribution of recoiled electrons to the PIXE spectrum in the energy region of 0~100 keV was ~20 % of its background spectrum. It was not enough to suppress the Compton scattering background by using the present system.

Angular correlations for the {sup 12}C(e,e{sup {prime}}n){sup 11}C reaction in the giant resonance region have been measured for forward scattering at an effective momentum transfer of 0.35fm{sup -1}. The angular correlation for the ground-state transition indicates a strong forward-backward asymmetry at the peak of the giant dipole resonance ({omega}=22.5MeV), which is different from the nearly symmetric angular correlations observed for the {sup 12}C(e,e{sup {prime}}p{sub 0}){sup 11}B reaction. Recent random-phase approximation predictions fail to reproduce the experimental angular correlations for both (e,e{sup {prime}}n{sub 0}) and (e,e{sup {prime}}p{sub 0}), predicting the opposite patterns to those observed. {copyright} {ital 1997} {ital The American Physical Society}

A new beam line to allow parasitic experiments in two separate experimental halls has been installed. The total length of the beam line is about 80 m. Two achromatic 90° deflecting systems have been incorporated. For the beam delivered to the second experiment, the beam diameter was 2 mm and the emittance was 1 mm mrad. The duty factor was reduced to an average of 50% from 80%. This decrease was satisfactorily recovered using a deflector system synchronized with the beam pulse. The tagged photon beam, and experimental conditions were significantly improved when the transported beam was used. Successful parasitic experiments involving electron scattering and tagged photon experiments have now been demonstrated.

The electrofission cross section of $^{182}\mathrm{W}$ was measured in the range 80--180 MeV. A pronounced inflexion, corresponding to a sharp structure in the (\ensuremath{\gamma},f) curve, shows up around 140 MeV. A photofission model, based on a photopion-deuteron reabsorption process, was worked out to explain this finding. Good agreement between calculation and experimental data was achieved.

High temperature deformation and microstructural evolution were studied in tension using single phase polycrystalline Ni 3 Al doped with boron. The samples with grain sizes from 3.0 to 18 μm were rapidly H 2 gas-quenched immediately after straining in order to examine deformed structures and to elucidate the mechanism of superplastic deformation. A stress peak appears at a strain of less than 0.1 more remarkably with increasing initial grain size, and with increasing strain rate or decreasing temperature. Dynamic recrystallization (DRX) initiates along prior grain boundaries at near the peak stress and develops toward grain interiors on further deformation, leading to the evolution of necklace structures. A rapid decrease in flow stress after the peak is mainly due to grain boundary sliding at interfaces between DRX grains. In contrast, work hardening takes place at low and moderate strains for samples with smaller initial grain sizes, when they are deformed at lower strain rates or higher temperatures. Under these conditions, grain boundary sliding occurs predominantly accompanied with grain coarsening due to DRX. Superplastic elongation appears in specimens exhibiting no significant behavior of work softening or work hardening. It is concluded that work softening or hardening behavior depends sensitively on the relative difference between the initial grain size and the stable DRX grain size evolved at high strains, and high temperature deformation of Ni 3 Al can be controlled by grain boundary sliding assisted by DRX.

The absolute electrofission cross sections of Au and Ta were measured in the energy interval 40-250 MeV. Pronounced inflexions of the (e,f) curves are observed for both Au and Ta around 200-220 MeV, which are signatures of structures in the corresponding photofission cross-section curves. We show that these ( gamma ,f) structures are related to peculiarities of the thermalization process.

The absolute electrofission cross sections of Au and Ta were measured in the range 25--180 MeV. The deduced photofission cross section shows, for both Au and Ta, a pronounced dip around the photopion threshold ([similar to]140 MeV). This ([gamma],[ital f]) dip is interpreted as a consequence of a probable photopion absorption in a stopped pion regime.''