Application of accelerators for the research and development of scintillators

We introduce experimental systems which use accelerators to evaluate scintillation properties such as scintillation intensity, wavelength, and lifetime. A single crystal of good optical quality is often unavailable during early stages in the research and development (R&D) of new scintillator materials. Because of their beams' high excitation power and/or low penetration depth, accelerators facilitate estimation of the properties of early samples which may only be available as powders, thin films, and very small crystals. We constructed a scintillation spectrum measurement system that uses a Van de Graaff accelerator and an optical multichannel analyzer to estimate the relative scintillation intensity. In addition, we constructed a scintillation time profile measurement system that uses an electron linear accelerator and a femtosecond streak camera or a microchannel plate photomultiplier tube followed by a digital oscilloscope to determine the scintillation lifetimes. The time resolution is approximately 10 ps. The scintillation spectra or time profiles can be obtained in a significantly shorter acquisition time in comparison with that required by conventional measuring systems. The advantages of the systems described in this study can significantly promote the R&D of novel scintillator materials.     

Relocations are determined by firms' relationships with financing institutions: A paper based on network data for Japanese firms

Both theoretical and empirical research studies the factors influencing firms' location choices. This paper presents a new viewpoint by considering relationship continuity to explain small-scale relocations and relocations of small and medium-sized enterprises (SMEs), which represent the majority of firms. The influences of firms' relationships with financing institutions are studied using a two-stage nested logit model. Consequently, the positive effect of relationships on location choices is revealed and the factors preventing firms from moving are described. The model is valid for estimating relocations to medium-sized cities, and the influences on shrinking firms as opposed to expanding firms are especially strong.     

Acid hydrolysis behaviour of microbial cellulose II

A mutant strain of Acetobacter xylinum produces cellulose of anomalous band-like form (‘native band’), and this material has been found to be cellulose II, presumably having a folded-chain structure (according to recent work by Kuga et al.). In addition to the previous results of electron diffraction, X-ray analysis showed that this band material was composed of virtually pure cellulose II. We have studied the acid hydrolysis behaviour of this material to obtain additional evidence for the proposed structure. When hydrolysed with 1 N hydrochloric acid at 100°C, the degree of polymerization (DP) of the material decreased rapidly from 322 ( ) to 18.3 ( ). The latter value (levelling-off DP) corresponds to the observed width (10 nm) of strand-like constituents of the band material. The sample dissolved in and regenerated from 8.75% aqueous sodium hydroxide lost its original characteristic morphology and became irregular-shaped agglomerates. The leveling-off DP of this regenerated sample was 55.2 ( ), a typical value for common regenerated celluloses. These findings as a whole strongly suggest that the cellulose molecules in the native band are selectively cleaved at sharply folded parts by acid, producing fragments of the length of folding periodicity.     

岩崎美术馆

日本鹿儿岛指宿／Ibusuki,Kagoshima,Japan 1978-1987指宿的强烈光线极具亚热带特色,这里的蓝天白云和冲绳的非常相似。该建筑建在近海的乡村地带,计划将其建造成为与丰田鞍池纪念馆风格迥异的别墅形式。Strong lights in Ibusuki have significant subtropical characteristics,and the blue sky and white clouds here are extremely similar to thosein Okinawa.The building is located in the offshore countryside and planned to be built into a villa whose style is g reatly different from thatof Toyota Kuragaike Commemorative Hall.正对着入口及庭院的露台（我们称之为光室）与负责主展厅顶部采光的光室相对应。在混凝土结构中,露台部分的框架尺寸堪称最小,在框架内设置有十字型的横杆。     

Examination of Staphylococcus aureus survival and growth during cheese-making process

Inoculation tests of Staphylococcus aureus were performed to evaluate the risk of toxic hazard in cheese manufacturing processes. S. aureus was inoculated into pasteurized milk or cheese curd, and the survival and growth were examined. S. aureus grew only slightly or decreased in cell number under the manufacturing condition of semi-hard type cheese or soft-type cheese. Under the conditions of the fresh cheese making process, S. aureus slightly increased in cell number, though no enterotoxin was detected. In processed cheese, S. aureus did not grow at all. Growth inhibition of S. aureus by lactic acid produced from starter culture was suggested to be the cause of growth inhibition in the natural cheese.     

Preserving the strength of corrugated cardboard under high humidity condition using nano-sized mists

The paper evaluates the adsorption of water vapor and compression strength of three types of commercially made corrugated cardboard boxes for packing strawberry, mizuna and broccoli. The experiments were conducted on the specimens and empty cardboard boxes at constant temperature and 95% relative humidity (RH). The samples were stored under the environments of two types of mists, namely nanomist and ultrasonic-mist over a period of 7 days. Nano-sized mist, which are called nanomists and defined as particles of about 60 nm in diameter, easily evaporate and are considered not to damp the corrugated boxes in comparison with the larger size ultrasonic-mists. The change in moisture content of the samples was first measured at intervals of 6, 12 and 24 h and then daily over 7 days. Compressive strength test was measured by the means of using a tensile and compression testing machine. The results revealed that moisture content of both specimen and cardboard box tests exposed to the nanomist and ultrasonic-mist at the end of experiments was 19.9% d.b. and 30.4% d.b., respectively (dry basis: g-water in material/ g-dry weight) although temperature and relative humidity were almost the same for both cases. Furthermore, the strength of cardboard specimens conditioned with nanomist after 7 days at 5.8 °C and 94.2% RH decreased by 44.3–56.9% whilst under ultrasonic-mist condition it reduced by 66.5–70% depending on the types of cardboards. Similarly, maximum compressive load of corrugated cardboard boxes exposed to nanomist and ultrasonic-mist decreased gradually over the time. It was analytically predicted that the boxes exposed to nanomist maintained its maximum compressive load at 28%, whereas those exposed to ultrasonic-mist remained at 14% after 7 days. The maximum compressive load of corrugated cardboards exponentially decreased with an increase in moisture content.     

Monte Carlo simulation of the collective behavior of food particles in pneumatic drying operation

Although most of the time drying operation aims at controlling the mean batch behavior, the quality of the final product is often related to the individual behavior of the supplied materials in a batch. The mean batch models provide limited information for quality evaluation studies. Since the initial physical and thermal properties of rice powder in a batch influence the final condition of product dried with a pneumatic dryer, a Monte Carlo simulation with initial random parameters is useful to investigate the individual behavior of rice particle during pneumatic drying. In this study, we analyzed the influence of initial moisture content and particle diameter of rice powder on the conditions of the final product in pneumatic drying process. Samples of initial moisture content and particle diameter distributions were generated by means of the covariance decomposition algorithm and Monte Carlo simulations with 5000 runs based on momentum, energy and mass balances between drying air and rice particles were performed to obtain the profiles of the response variables, rice powder temperature, moisture content and particle diameter, in a pneumatic dryer. The developed pneumatic conveying drying (PCD) model could describe the complex behavior of rice particles in a batch.     

Effect of vapors from fractionated samples of propolis on microbial and oxidation damage of rice during storage

The efficacy of vapors from polar and non-polar sub-fractions of propolis on microbial and oxidation control during rice (Oryza sativa, hinohikari var.) storage was evaluated. The sub-fractions (absolute ethanol, methylene chloride, hexane extracts: AEPEV, MCPEV and HEPEV, respectively) were infused in synthetic adsorbents and their volatiles released during storage (6 months). HEPEV, MCPEV and AEPEV treatments inhibited molding and post-inoculation bacterial colonization (1.1, 1.1, 0.9 and 1.3, 1.2, 1.1 log₁₀ cfu/g reductions, respectively) on brown rice. AEPEV treatment suppressed fat acidity damage of milled rice at 30 °C to conventional cold storage level (5 °C) and differential Gram staining of bacteria isolated after the treatment indicated a dominant Gram-positive bacterial distribution. The concentrations providing 50% inhibition of 2′,2′-diphenylpicrylhydrazyl free radical scavenging were 9.8, 3.2 and 2.8 μg/μl for hexane (HEPE), absolute ethanol (AEPE) and methylene chloride (MCPE) extracts, respectively. The oxidative degradation rate was lowest for AEPE (4.3 × 10⁻⁴ min⁻¹) and highest for HEPE (1.9 × 10⁻³ min⁻¹) in the β-carotene bleaching assay. Gas chromatograph mass spectrometry revealed that AEPE had the highest amount of caffeic acid and caffeic acid phenethyl ester. Ultimately, the volatiles from the propolis sub-fractions had varied potential in rice quality preservation.     

Pulse switching characteristics of MAGTs for pulsed power applications

For pulsed power systems such as lasers and accelerators, semiconductor switches with their longer service life have actively been developed as replacements for thyratrons. The MOS-driven thyristors are suitable for pulsed power applications because they have high-power handling and fast turn-on capabilities. The MOS-assisted gate-triggered thyristor (MAGT), designed especially for pulsed power, is a promising candidate in this field. This paper presents the results of an investigation into the performance of MAGTs. Using a pulse-forming network (PEN), the pulse-switching characteristics and the dynamic resistance characteristics during the current flow are investigated. A maximum current density of 21.8 kA/cm² and di/dt of 106 kA/μs/cm² with 1550-V anode voltage on a single-shot basis were obtained. Furthermore, a life test with 10⁹ shots at a high repetition rate showed no degradation in the observed characteristics. Based on these experimental results, a carrier flow model of MAGT during turn-on process is proposed and the turn-on mechanism is considered.