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To overcome global warming issue and energy shortage problem, economical hydrogen production technologies from renewable energy or unused fossil fuel with carbon capture technology are being developed all over the world. However it becomes the large problem that it is necessary to reconstruct energy infrastructures for production, transportation and usage of hydrogen and to entail a vast cost. Against this problem, for effectively utilizing existing energy infrastructures, we are developing a methane producing technique from water and carbon dioxide by using renewable electricity instead of hydrogen production. Specifically, solid oxide electrolysis cell (SOEC) technology for producing syn-gas with high efficiency has been developed and we have succeeded in trial manufacture tubular SOECs whose sin-gas production rate is more than 3.5 sccm/cm2 at the operating temperature of 750 oC and electrolytic voltage of 1.35V. Therefore, in this paper, the numerical models of an SOEC methane production system and a conventional methane production system were made in reference to performance of the tubular SOECs and dependence of performance of the each system on operating conditions, such as operating temperature, feed gas composition, is analyzed and compared with each other. The methane producing system which combined a water electrolysis system with a high temperature water-gas shift reactor was considered as a conventional system. From the result of the analysis, advantage of SOEC methane production system is clarified.

Slurry coating method for fabricating tubular solid oxide electrolysis stacks operated at 700~800oC is developed. To improve cell performance at the low temperature, the thickness of the electrolyte layer is tried controlling about 10μm. By using this process, the SOEC stack whose input power is about 100 W is fabricated and its performance is measured. From the measurement, it is clarified that the hydrogen production rate at 750oC goes up to 678 sccm (3.08 sccm/cm2) at the thermoneutral voltage and steam utilization of 75 %. Furthermore, impedance of the stack is analysed by AC impedance method.

Tubular solid oxide electrolysis cells (SOECs) whose operating temperature is reduced to 700~800 oC are developed. To improve cell performance at the low temperature, Sc2O3 stabilized ZrO2 is chosen as electrolyte material and the thickness of the electrolyte layer is tried controlling about 10μm by slurry coating method. As a result of performance test, it is clarified that current density at thermoneutral point goes up to 0.46 Acm-2 at 750 oC. Furthermore, degradation phenomena in long term operation more than 1200 h are observed.

Tubular SOECs with operating temperature reduced to 700~800oC are developed. To improve cell performance at low temperatures, Sc2O3 stabilized ZrO2 is chosen as the electrolyte material and thickness of the electrolyte layer is tried to be controlled to about 10 μm. Test electrolysis cells are fabricated by using slurry coating method. Dependence of cell performance on operating conditions is measured. Further, AC impedance method is applied to the cells to estimate interfacial overvoltage. From the experiment, it is clarified that the hydrogen production rate at 750oC goes up to 3.6 sccm/cm2 at the thermoneutral voltage. This value is more than 2 times of that of the commercial alkaline electrolysers.

Tubular solid oxide fuel cells (SOFCs) composed of Ni- yttria- stabilized zirconia (YSZ) supported scandia-stabilized zirconia (SSZ) electrolyte film, doped ceria interlayer and strontium-doped cobaltile electrodes were successfully developed for reduced-temperature operation. The SOFCs were fabricated by adopting a slurry coating technique, which allows to prepare a ceramic layer with a thickness varied between 1~ca. 150μm, and a co-fire process. The fabrication process was investigated in detail for realizing low cost SOFCs with high degree of straight, round, high reproductive quality, and high electrochemical performance. Flawless dense electrolyte thin film less than 10μm was achieved on porous tubular Ni-YSZ substrate with the thickness that thicker than 500μm. Primary results of electrochemical performance test show that the a fabricated cells with (Sm0.6Sr0.4)CoO3 electrode could produce ca. 0.4 Wcm-2 of power density at H2 utilization of 60% at 800oC.

For producing pure hydrogen with high efficiency and low cost, Solid oxide electrolysis cells (SOECs) assisted by low calorie gas were proposed. To use low coat metal as electrodes and an interconnector, tubular SOECs operated at 700~800oC were tried fabricated. The thickness of the electrolyte in the SOEC reduce to approximately 10 μm by using Slurry coating technique and electrolytic performance of the fabricated cells was measured. As a result of this experiment, the hydrogen production rate of a testing cell whose effective electrode area was 18.8 cm2 achieved 56 sccm at 800oC under practical operating condition. Further, the way of improving cell performance was discussed.

A high-precision method to measure efficiency of fuel cells with a 0.1% margin of error is proposed. This method is principally divided into two procedures: determining the composition of fuel gas to be fed into a fuel cell system and measuring the flow rate of the fuel gas. The composition of the fuel gas is determined by an FTIR (Fourier transform infrared spectrometer) and/or a QMS (quadrapole mass spectrometer) with a built-in sonic nozzle sampling system. The flow rate was measured by the tracer gas method; that is, a given amount of tracer gas, such as one of the noble gases, was introduced into the line of the fuel gas, then, the mixed gas was sampled at the point where the tracer gas had been well mixed, and the concentration of the tracer gas was determined by the QMS. In this paper, a gravimetric calibration method using a highly sensitive balance is also proposed for flow control of the tracer gas. Also proposed are calibration of the FTIR and the QMS to establish the required low uncertainty or high accuracy of the measurement of the efficiency.

Application of (Sm 0.5 Sr 0.5 )CoO 3 (SSC) as a cathode material on Zr 0.89 Sc 0.1 Ce 0.01 O 1.95 electrolyte for reduced temperature operation SOFCs was investigated in detail. As a protective layer for the electrolyte, doped ceria thin films were fabricated on the electrolyte by a cost effective wet ceramic process using nanometer Ce 0.8 Sm 0.2 O 1.9 and submicrometer Ce 0.9 Gd 0.1 O 1.95 powders. The impact of doped ceria interlayer on the performance of (Sm 0.5 Sr 0.5 )CoO 3 cathode was investigated by XRD and AC impedance measurements. It was found that controlling the microstructure of the interlayer is important for (Sm 0.5 Sr 0.5 )CoO 3 cathodic performance. The SSC cathode deposited on SSZ electrolyte coated by (Ce 0.8 Sm 0.2 )O 1.9 or (Ce 0.9 Gd 0.1 )O 1.95 interlayer can reach an interface conductivity of 4.4 S/cm 2 or 7.2 S/cm 2 at 700°C, respectively.

For developing small SOFC systems for portable applications, the characteristics of reforming DME by using carbon dioxide are investigated. After calculating composition of produced gas and condition of carbon deposition, relationship between the feed condition of DME and output power of a tubular SOFC is measured. A quadrupole mass spectrometer and a Fourier transform infrared spectrometer are used for measuring exhaust gas accurately. Carbon deposition conditions on the anodes of the cell and in fuel feed pipes are also investigated. From these results, potential of the carbon dioxide reforming of DME is clarified.

アルカリ金属熱電変換(AMTEC)のカソード側電極内の物質移動とその経時変化特性は出力性能に大きく影響する要因である. Mo電極の性能は1100 K以上の温度域で急激に劣化することが既に報告されている. しかしより低い温度域では, Mo電極の高い初期性能はより長時間維持される可能性がある. 本研究では温度範囲900-1050 Kにおいて, Na低圧蒸気雰囲気を利用する電極評価セル(SETC)による実験を実施した. 電極の限界電流密度を測定し, Na物質移動特性を自由分子流と仮定した無次元形状係数Gにより評価した. Mo電極部温度904 K, 1007 K, 1056 Kの作動条件において, 約100-150時間でGはそれぞれ20, 78, 122の一定値に収束する結果を得た. 904 Kの測定結果よりAMTEC 出力特性を検討すると, 従来のTiN電極(G = 150)と比較してMo電極は約50%の出力増加が期待できることを明らかにした.

In the present work, the current–voltage characteristic at 700 °C across a thin film of Ce0.8Gd0.2O1.9 (CGO) was analyzed by local equilibrium theory. The performance of a Ni–Ce0.8Sm0.2O1.9 (CSO20) anode and a La0.6Sr0.4Co0.8Fe0.2O3–Ce0.8Gd0.2O1.9–Ag (LSCF–CGO–Ag) cathode was studied at 500–700 °C by three-probe complex impedance measurements. If the electrodes are used on a thin film of Ce0.8Gd0.2O1.9 (CGO20) electrolyte, the calculation showed that the maximum energy conversion efficiency at 700 °C could reach 0.43, where the power density was 0.62 W/cm2, which is large enough for practical operation.

Performance of an La0.6Sr0.4Co0.8Fe0.2O3–CGO–Ag cathode (where CGO is Ce0.8Gd0.2O1.9) on a Ce0.8Sm0.2O1.9 electrolyte was studied by the three-probe AC impedance method at the steady state of various DC bias currents. The electrode consisted of a porous layer of La0.6Sr0.4Co0.8Fe0.2O3–CGO (30 wt.%) and a layer of Ag particles coated on the surface. The Ag coating was used to improve the oxygen exchange reaction activity. As a result, an interface conductivity greater than 1 S/cm2 was obtained at 600 °C with a low activation energy. The dependence of the AC impedance on the frequency was analyzed in order to clarify the reaction steps in the oxygen reduction mechanism.

We prepared a recombinant retroviral vector expressing the human T-lymphotropic virus type-I tax gene. Infection of WKA/H rat splenocytes yielded T-cell lines which proliferated continuously in media supplemented with exogenous interleukin-2 (IL-2) after the control cells ceased to grow. The phenotype of these cells closely resembled that of typical adult T-cell leukemia cells and tax-immortalized human T cells; i.e., positive for CD3, CD4 and IL-2 receptor alpha-chain. Chromosomal analysis revealed that about 10% of the tax-transduced T cells had several chromosomal abnormalities. We also performed in vivo characterization of tax-transduced splenocytes by injecting them into newborn syngeneic rats soon after in vitro infection. Maintenance of the injected tax-transduced cell population and in vivo expression of the tax gene was confirmed in the splenocytes of the injected rats by polymerase chain reaction. However, development of obvious disease was not observed in these rats for up to 18 months after inoculation. These results indicate that tax is capable of immortalizing rat mature CD4+ T cells in vitro but may be insufficient for full transformation of these cells in vivo. Our in vivo system using retrovirally tax-transduced rat T cells could facilitate investigation of the additional genetic events that cooperatively transform T cells transduced with tax gene.

The alkali metal thermoelectric converter (AMTEC) utilizing the sodium ion conducting β-alumina is a device to convert heat energy to electric energy directly. It is characterized by high conversion efficiencies, high power densities, no moving parts and low maintenance requirements. Because of these merits, AMTEC is one of the most promising candidates for aerospace power systems, remote power stations and dispersed small-scale power stations. In this paper, the experimental results of the series-connected cells and the theoretical considerations about internal resistances have been reported. For the single cell, the open voltage of 1.37 V and the maximum power of 7.89 W and maximum power density of 0.40 W/cm2 at the sodium temperature of 1077 K have been obtained. For the two series-connected cells, the open voltage of 2.60 V and the maximum power of 12.3 W at the sodium temperature of 1016 K have been obtained. This power was about 90 percent of the sum power of two cells. This power decrease is due to the resistance of the current-collecting busbar. It is necessary to optimize the current-collecting busbar considering the electrical resistance and heat conductance.

The alkali metal thermoelectric converter (AMTEC) utilizing the sodium ion conducting β-alumina is a device to convert heat energy to electric energy directly. It is characterized by high conversion efficiencies, high power densities, no moving parts and low maintenance requirements. Because of these merits, AMTEC is one of the most promising candidates for aerospace power systems, remote power stations and dispersed small-scale power stations. In this paper, the experimental results of the series-connected cells and the theoretical considerations about internal resistances have been reported. For the single cell, the open voltage of 1.37 V and the maximum power of 7.89 W and maximum power density of 0.40 W/cm2 at the sodium temperature of 1077 K have been obtained. For the two series-connected cells, the open voltage of 2.60 V and the maximum power of 12.3 W at the sodium temperature of 1016 K have been obtained. This power was about 90 percent of the sum power of two cells. This power decrease is due to the resistance of the current-collecting busbar. It is necessary to optimize the current-collecting busbar considering the electrical resistance and heat conductance.

Mechanical efficiencies have been compared for several plant configurations utilizing a pressure-retarded osmosis (PRO) energy converter. In this comparison reliance has been placed on previously obtained experimental data of Honda in a reasonably sized PRO module with hollow fibers sized for PRO use. These data were obtained with a 3.5 percent NaCl solution, i.e. one fairly close to sea water. The comparisons indicate that the continuous flow, terrestrial PRO plant will be too low in efficiency to be effective. The continuous flow, underground PRO plant will be much more efficient but requires that most of the equipment be located in an underground cavern at a depth of about 90 meters below the surface of the sea. The alternating flow, terrestrial PRO plant has high efficiency, but requires the use of two pressure vessels in addition to the usual PRO equipment.

Chromosome findings in cultured skin fibroblasts from a patient treated with an anti-cancer drug, pepleomycin sulfate, for his penis cancer are reported. In two batches of specimens (days 16 and 34, respectively), out of 120 cells examined, a total of 26 abnormal cells (21.7%) were found with no common chromosome abnormalities; there were no clones. This cytogenetic pattern of abnormalities without clones in cultured skin fibroblasts differs from that seen in congenital disease or radiation-exposed skin fibroblasts. It is suggested that the anti-cancer agent is the most likely etiological factor for these uncloned chromosome abnormalities in cultured skin fibroblasts.

長崎原爆被爆者における皮膚に対する原爆放射線の影響を観察する一つの方法として, 皮膚培養細胞の染色体検索を実施した。対照群としての非被爆者の皮膚培養細胞からはほとんど染色体異常は観察されなかつたが, 有意の放射線を浴びたと考えられる被爆者の皮膚培養細胞中には, 原爆被曝から40年余を経た現在もなお, 放射線に起因すると考えられる染色体異常が観察された。染色体異常率は推定被曝線量の多い被爆者に高率に認められ, これらの異常細胞の中には同一の異常核型を有するクローン形成も観察される。これらの事実は, 原爆被爆者のなかでも高線量被曝者の皮膚細胞には相当なDNA障害が生じ, それらの細胞がクローン増殖していることを意味している。このことはまた, 今後早急に被曝者における皮膚癌発生率の疫学調査が必要であることを示唆している。

This work discusses thermal designing and performance of a compact type AMTEC system. The compact type AMTEC system uses multiple small-sized cell components, which consist of sodium beta-alumina solid electrolyte tubes of 3 mm in outer diameter and simple freestanding type capillary structure. When the cell components are arranged in a canister, the pressure drop due to sodium vapor flow from the electrode to the condenser becomes a critical parameter. The effect of the pressure drop was analytically evaluated and the optimum geometrical arrangement was considered. The typical calculated result shows that a 37-tube cell having a base area of 7.5 cm/sup 2/ has a predicted output power of about 5 W at relatively low operating temperature of 900 K. This output power is almost equal to that of the high temperature type cells operating around 1,100 K. Structure and heat transfer analyses necessary for the miniaturization and the low temperature operation are reported in this paper. Preliminary thermal design on a cascaded system with the AMTEC and the thermionic converter is also discussed.

To apply an intense pulsed ion beams produced in plasma focus (PF) to material processing, characteristics of the beam was evaluated. In the experiment a Mather type PF was used which was pre-filled with N 2 (5.5 Pa) to produce nitrogen ions. To clarify the mechanism of the production of impurity ions, two types of anode (type A; rod type and has an anode tip on the top, type B; hollow shape top) were used. In both type peak discharge currents of 550 kA were obtained at 1.5 µs after the rise of the current. From the measurement by Thomson parabola spectrometer large quantity of copper ions were observed when type A is used and the purity for type A and type B were evaluated to be 26 % and 90 %, respectively. To enhance the energy and the charge state of the nitrogen ions the PF with type B anode was pre-filled with mixture of nitrogen and hydrogen (N 2 20, H 2 180 Pa). From the TPS measurement, multiply ionized nitrogen ions (N1−5+) of energy more than several MeV were observed with protons of maximum energy 1 MeV. Thin layer of amorphous silicon was irradiated by the ion beams produced in PF and we found that the layer was crystallized.

Two immortal fibroblastic cell strains (substrains) were established by culturing healthy skin cells obtained from a high-dose atomic bomb survivor (female, age 76 years, 5.14 Gy) for more than 4 years. Designated FM-U and FM-M, the two substrains share the same marker chromosome, t(5q-;6p+), but are karyotypically different, possessing hypodiploid chromosome numbers (39-43) in the former and hypertriploid (69-76) in the latter. Thus far, the two strains have passed through 117 and 156 subcultures or more than 230 and 310 cumulative population doublings, respectively, each passage requiring 4-6 days in the former and 3-4 days in the latter. In the process of immortalization, sequential rearrangement among various chromosomes presumably due to telomeric and interstitial telomeric fusions took place following the telomere shortening, particularly in the senescence and postsenescence phase cells. Of particular interest is the fact that loss of heterozygosity (LOH) of the p53 gene was demonstrated in these immortalized cell populations. In addition, the allelic patterns of the LOH of p53 differed. Further evidence indicative of infinite proliferation was demonstrated in both strains, such as the telomere elongation and the significantly low frequency of cells possessing dicentric chromosomes.

It is shown that curved slab targets are effective in compensating x-ray refraction due to electron density gradient in the expanding plasma. Significant improvement in the beam divergence and laser intensity has been observed. Soft x-ray laser of 1 mrad divergence has been generated in double- pass amplification of a collisionally-excited Ne-like Ge laser with the curved target. Generation of a polarized beam with a polarizing half cavity is described. Initial results of in-line holography as well as Fourier transform holography using the Ge laser as the light source are also presented.

We propose a new image processing approach to construct intermediate parallax-images from parallax-images at coarsely sampled viewpoints for Holographic Stereograms. Compared with the usual method that requires a large number of parallax-images, this approach reduces recording labor. In our approach, the intermediate parallax-images are made by projections of 3-D surface data, which are computed from several given parallax-images. It uses a new technique to reconstruct 3-D surface data of object scenes. The 3-D surface data is reconstructed from original parallax-images and camera positions. Almost all conventional techniques of stereo-matching need preprocess of feature extraction, and match only one stereo-pair at once. This technique simultaneously treats all given parallax images to find the depth map. In addition, feature extraction is not required in the matching process. Therefore it is possible to apply to almost all kind of scenes for holographic stereograms.

Two clonal fibroblast cell lines with simple chromosome aberrations-one with del(3)(p24) and the other with t(1;16)(q21;q11.2)-were established from a high dose (5.14 Gy) female atomic bomb survivor by serial culture of skin fibroblasts. These two types of clonal cells showed a more extended life span than did the cells with 44 other types of chromosome aberrations and normal cells. In addition to these results, a prominent clonal population was observed in the peripheral blood cells in this subject. It is assumed that these clonal populations arose in vivo as a result of radiation exposure to the atomic bomb.

Of the 66, 276 Nagasaki atomic bomb survivors registered at the Scientific Data Center for the Atomic Bomb Disaster at the Nagasaki University School of Medicine, 140 were identified as having skin cancer from the records of 31 hospitals in Nagasaki City. From the cases of these survivors, a statistical analysis was made of the incidence of skin cancers by age, gender, histology and latency period in Nagasaki atomic bomb survivors. The results showed a high correlation between the incidence of skin cancer and distance from the blast hypocenter, and that the incidence of skin cancer in the Nagasaki survivors appears now to be increasing with exposure distance., Journal of radiation research. 1991, 32(Supple_2), p.217-225

Application of (Sm 0.5 Sr 0.5 )CoO 3 as a cathode material on Zr 0.89 Sc 0.1 Ce 0.01 O 1.95 electrolyte for reduced-temperature operation solid oxide fuel cells (SOFCs) was investigated in detail. As a protective layer for preventing the unfavorable solid-state reactions between materials, doped ceria thin films with an apparent density range between 50 and 80% were fabricated on the electrolyte by a cost-effective wet ceramic process using nanometer (Ce 0.8 Sm 0.2 )O 1.9 and submicrometer (Ce 0.9 Gd 0.1 )O 1.95 powders. The impact of doped ceria interlayers on the performance of (Sm 0.5 Sr 0.5 )CoO 3 cathode was investigated by X-ray diffraction and ac impedance measurements. It was found that controlling the microstructure of interlayers is important for (Sm 0.5 Sr 0.5 )CoO 3 cathodic performance. The (Sm 0.5 Sr 0.5 )CoO 3 cathode deposited on Zr 0.89 Sc 0.1 Ce 0.01 O 1.95 electrolyte coated by (Ce 0.8 Sm 0.2 )O 1.9 or (Ce 0.9 Gd 0.1 )O 1.95 interlayer can reach an interface conductivity of 4.4 or 7.2 S/cm 2 , respectively, at 700°C.

An anode-supported tubular solid oxide fuel cell (SOFC) with a thin electrolyte film for reduced temperature operation was fabricated by a wet cofire process. Instead of the traditional extrusion method, the anode substrate was formed by a tape-cast method. This allows design the substrate with some advantageous configurations that can improve the performance of SOFCs. Sc 2 O 3 and Y 2 O 3 -stabilized zirconia electrolyte films were fabricated on the substrate by a modified slurry dip-coating method and then cofired. In order to use (La 0.6 Sr 0.4 )CoO 3 cathode, a thin (CeO 2 ) 0.9 (GdO 1.5 ) 0.1 interlayer was also fabricated by the slurry dip-coating method. The fabricated tubular cell generated electricity successfully between 600 and 850°C. Power density of ca. 170 and 220 mW/cm 2 was achieved at 600 and 700°C, respectively, however, the ohmic resistance was larger than expected. Because (CeO 2 ) 0.9 (GdO 1.5 ) 0.1 interlayer was used, ohmic resistance could be high due to the formation of a layer of (Zr,Ce)O 2 solid solution at the zirconia/ceria interface. The gaseous diffusion resistance governed the performance between 700 and 850°C. Better performances of the anode-supported tubular SOFCs can be achieved by further optimizations for the zirconia/ceria interface, control of both porosity and thickness of the anode substrate, as well as improvement of the (La 0.6 Sr 0.4 )CoO 3 cathode.

Analysis of data on stable chromosome aberrations collected between 1968 and 1985 by the Radiation Effects Research Foundation (RERF) on 1703 individuals exposed to A-bomb radiation in Hiroshima and Nagasaki, Japan, reveals different dose-response relationships in the two cities, as well as significant effects of both time of assay and age at exposure. In Hiroshima, the proportion of cells with aberrations increased by 0.080 per sievert at low doses, assuming a constant neutron radiation RBE of 10 relative to gamma radiation, for assays performed during the latest period (1981-1985). In Nagasaki, the low-dose increase was 0.0126 per sievert. There was evidence that radiation exposure was more effective for producing stable aberrations at some younger ages at exposure, although the interpretation of this interaction is difficult. Modeling neutron and gamma-ray components of dose separately in a way which allows the neutron RBE to vary with dose yielded an estimated low-dose limiting value of RBE of 707 (95% confidence bound 200-infinity), with a low-dose response of approximately 0.008 aberrations per sievert. This RBE is much higher than the published RBEs for induction of aberrations in vitro. The high estimated RBE and the differences in dose response by city both are suggestive of systematic dose estimation errors in which either neutrons were underestimated in Hiroshima or gamma rays were overestimated in Nagasaki.

1. 1. Glutamyl kinase in a homogenate of blowfly abdomens was not inhibited by proline and its analogues, and was found only in the mitochondrial fraction. 2. 2. Proline was biosynthesized from glutamate only in a cell-free system prepared from blowfly abdomen.

多数の tetrachlorophthalamic acid 誘導体, および, 関連化合物を合成し, それらの稲白葉枯病抑制効果をしらべた. N-置換フェニル基をもつ3, 4, 5, 6-tetrachlorophthalamic acid 誘導体は, 稲白葉枯病にすぐれた抑制効果を有し, かつ, 浸透殺菌作用をも有することがわかった. なかでも, N-(1-naphthyl)-3, 4, 5, 6-tetrachlorophthalamic acid および, N-(2, 3-dichlorophenyl)-3, 4, 5, 6-tetrachlorophthalamic acid の効果がすぐれていた.

2-hydroxymethyl-3,4,5,6-tetrachlorobenzamide 誘導体5種を相当する 3,4,5,6-tetrachlorophthalimide を sodium borohydride で還元して合成した. これらの化合物の植物病害に対する防除活性をしらべたところ, イネ白葉枯病にはまったく効かなかったが, イネいもち病, キュウリ炭疽病には高い防除活性が認められた. 3,4,5,6-tetrachlorophthalamic acid 誘導体のイネ白葉枯病防除活性には, カルボキシル基が, 2-hydroxymethyl-3,4,5,6-tetrachlorobenzamide 誘導体のイネいもち病防除活性には, メチロール基がそれぞれ重要な役割を果たしている.

Studies were begun to determine the effectiveness of N-aryl-3, 4, 5, 6-tetrachlorophthalamic acids against bacterial leaf blight of rice, caused by Xanthomonas campestris pv. oryzae. The structure-activity relationship of many derivatives indicated that the presence of both the carboxyl radical and four chlorine atoms at phthalic acid moiety was structurally essential for effectiveness against the disease, and optimization of activity was obtained in a derivative (techlofthalam) having 2, 3-dichlorophenyl as the aryl group. Techlofthalam showed no activity in vitro against the causal bacterium, when estimated by a turbidimetric method. Soil application with techlofthalam was found to be considerably effective at 4kg per hectare both in the greenhouse and the field. With foliar application, however, extremely different efficacies were shown with two inoculation methods; excellent control against lesion development was realized by spray inoculation, but only poor control was obtained by needle prick inoculation. Intensive field evaluation proved that techlofthalam spray at 60 to 120g per hectare showed a stable and excellent effect. In order to know the mode of action of techlofthalam, the change in population and aggressiveness of the bacterium in leaves sprayed with a 100ppm solution were examined. There was a definite trend of change in bacterial populations at all spray times, 1 day before and 3 days after inoculation, and after lesion formation; the bacterial population started to decrease a few days after spraying, and then was stable at much lower levels. The bacterium isolated from a sprayed leaf had lower aggressiveness than one from an unsprayed leaf. In consideration of generation time (approximately 10 hours in the exponential growth phase) of the bacterium in rice leaf, these results suggested techlofthalam's direct inhibitory effect on the multiplication of bacterium on the leaf. Retardation of the increase in viable bacterial population was found by a static culture using Suwa's synthetic medium containing techlofthalam at 0.1ppm; this was practically the same concentration as that gaschromatographically determined in guttation droplets on rice leaves a few days after spraying. Some other results also gave support to the conclusion that techlofthalam displays bacteriostatic action in rice leaf. Techlofthalam has been practically used in Korea since 1979.

As a theoretical standard for evaluating the high incidence of centric fusion in man and mouse, the relative probabilities of occurrence of reciprocal translocation (Tr), inversion (In) and centric fusion (Fu) were estimated based on the random-contact-and-exchange model. It was shown by this model that centric fusion was extremely rare (Fu = 0.0002, In = 0.0521 and Tr = 0.9477 for a human haploid karyotype). On the other hand, the occurrence rate of centric fusion in human newborn babies and European feral mice was about 500-1,000 times higher than the theoretically expected values, which is termed here the "fusion burst". We suggest that the fusion burst may be induced by the physical proximity of telomeres on the nuclear membrane, and the exchange of DNA strands by errors of telomere replication mechanisms. The cytogenetical significance of the fusion burst is discussed with regard to the minimum interaction hypothesis proposed by Imai et al. (1986). We suggest two closely linked possibilities that (1) the fusion burst in man and mouse can theoretically be placed in karyotype evolution as a transitional phase in the main stream of the fission-inversion cycle, and (2) it may be accelerated by some unknown (mutagenic) factors other than ionizing radiation.

As a cold wall Faraday type generating channel, an improved peg wall type channel that consisted of peg pieces coated by Al2O3 thin layers was suggested and experimentally studied. The fundamental data being necessary to design channels were obtained in preliminary experiments and the channels for ETL Mark III, Mark II and Mark V MHD generators were designed by the aid of them. The long-operation test of 230 hr was carried out with Mark III, and then the generating tests were performed over ten minutes and for several hours under the high Hall field strengths on Mark II and Mark V MHD generators, respectively. Through these tests, the side walls endured satisfactorily, but traces of breakdowns on the inter-electrode insulators were observed on both anode and cathode sides under the very high Hall field strength in the case of Mark V. This paper mainly deals with the construction and durability of an improved peg wall type channel.