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Summary  

Neutron radiography (NRG) was applied to trace the development of discolored tissue in the wood of Japanese cedar (Cryptomeria japonica) after being infected with a canker fungus. Japanese cedar seedlings were wound inoculated with a virulent and avirulent isolate of a canker fungus, Guignardia cryptomeriae. Three, 7, 13 and 22 days after the inoculation, the seedlings were irradiated with thermal neutrons. The image on the X-ray film showed that the whiteness in the image corresponded to the water content in the sample. Discolored tissue and surrounding dry zones induced by the fungal inoculation were detected as dark areas, indicating water deficiency with a high resolution. Through image analysis, the dry zones were detected as early as 3 days after inoculation. Neutron images also showed the difference in the size of water deficient parts due to the tissue damage among the treatments. The neutron beam dose used in this experiment had no effect on the growth rate of the fungus on a medium, showing that NRG is an effective method for pathological research of trees.

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The paper was to establish an easy and effective method to investigate and develop a specific technological field from Japanese patent information. The walking technique of the biped humanoid robot was used as an example to study the relative research capabilities and patent citation conditions for patent owners and patent map by the searching method of the theme code for FI (File Index) and F-term classification system of the Japanese Patent Office (JPO). A formulated technical matrix of patent map was established to indicate that the ZMP (Zero Moment Point) control means was the main technology to achieve stabilized walking control of the humanoid biped robot. This method can aid to establish a specific technological matrix from the specific selected term codes (single viewpoint or multiple viewpoints) of the F-term list in the theme code of the JPO system through Boolean logical operations. The resulting particular technical fields were developed to improve the technological capability or seek the merging technology opportunities.

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The paper aims to clarify the extent to which the results of scientific-oriented research conducted by corporations are reflected in their application-oriented research. Focusing on large Japanese manufacturers of electrical machinery, the paper analyses firm-level data on presentations of scientific papers that represent the results of scientific-oriented research activities, citations of scientific papers in patents, and inventions. The electrical machinery industry, a prototypical science-based industry, has been placing a growing emphasis on scientific-oriented research during the 1990's as is evident from trends in R&D expenses, scientific papers, and inventions. Regression analysis results suggest a complementary relationship between citations of basic scientific knowledge as presented in scientific papers on the one hand and acts of invention on the other hand, in the sense that a rise in citations corresponds to a rise in inventions. Moreover, the results suggest that invention efficiency (number of patent claims per unit of R&D expenditure) has been increasing during the 1990's. Furthermore, the results suggest that, given the exogenous influences on the patent system in Japan, it is necessary to include the number of patent claims when attempting to measure corporate technology development activity through the volume of patent applications. However, there was no finding of a clear relationship between the number of scientific papers and inventions. Implications of these results for corporate R&D strategy are examined.

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The behavior rhenium in surface seawater (0-30 m) was studied using the samples collected at three locations off the coast of Aomori Prefecture, Japan. The physico-chemical forms of Re in seawater from other locations were also studied to verify the Aomori findings. It was found that almost 100% of Re was in dissolved forms, mainly ReO4 -, therefore, the Re concentration was constant from the surface to 30 m depth and ranged from 6.1-7.4 ng. kg-1. The Re concentration in the Sea of Japan side was slightly lower than those in the Pacific Ocean side. Possibly, low Re concentration was added by river waters from Japan and/or the Asian continent to the Sea of Japan side.

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Abstract  

Dietary intakes of radiocesium and non-radioactive cesium in Japanese were estimated using a market basket study and found to be 61 mBq and 9.1 ng per person per day, respectively. Food categories having higher Cs contents (per g-fresh) were found to be as follows: mushrooms 35.9 ng; nuts and seeds 33.6 ng; meats 26.8 ng; fishes and shellfishes 21.6 ng; potatoes 19.2 ng; seaweeds 10.2 ng; and milk and milk products 7.19 ng. For137Cs, higher contents (per kg-fresh) were as follows: mushrooms 1.7 Bq; nuts and seeds 0.23 Bq; fishes and shellfishes 0.16 Bq; meats 0.13 Bq; potatoes 0.11 Bq; seaweeds 0.092 Bq; and milk and milk products 0.089 Bq. Distributions of stable cesium in the 18 food categories were similar to those of radiocesium.

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The concentration and size distribution of210Po in particulate matters in the atmosphere were measured around the active volcano, Mt. Sakurajima in Kagoshima prefecture, Japan. The samples were collected eight times at four sampling points for the period from June 1994 to January 1996. The highest concentration of210Po was 2940 μBq/m3 at Akamizu located 2 km away from the crater of Mt. Sakurajima. The210Po concentrations decreased with the increase of distance from Mt. Sakurajima. The size distribution curves of210Po in the particulate matters showed that210Po is usually condensed to fine particles smaller than 2 μm in diameter. In addition, it was suggested that the210Po concentration in particulate matters collected at Akamizu was affected by the wind direction over Mt. Sakurajima.

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Dietary intakes of eighteen elements and 40K were estimated by Japanese subjects using a market basket study. High concentrations of most nuclides were found in 4 categories among 18 categories (nuts and seeds, bean products, seaweeds, and fishes and shellfishes). The main contributors were rice, bean products, and fishes and shellfishes. Daily intakes were estimated (in mg) as follows: sodium 3.91 . 103; potassium: 2.49 . 103; phosphorus: 1.09 . 103; calcium: 551; magnesium: 273; iron: 9.82; zinc: 9.41; manganese: 3.54; strontium: 2.52; rubidium: 2.34; copper: 1.61; barium: 0.543; chromium: 0.283; nickel: 0.172; lithium: 0.060; cadmium: 0.022; cesium: 0.0091; cobalt: 0.0095; and 40K: 89 Bq.

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Concentrations of99Tc were determined by inductively coupled plasma mass spectrometry (ICP-MS) on coastal seawater in the general environment in Japan. Technetium was enriched on iron hydroxide by repetitive co-precipitation method from a large volume of seawater and separated from impurities by solvent extraction and ion-exchange techniques. The concentrations of99Tc were 1.0 to 7.4 Bq1–1, which was one order of magnitude lower than the level reported on seawater from general environment by beta-ray counting. Concentrations of137Cs determined on the same seawater were 3.7 and 3.9 mBq1–1. The activity ratio of99Tc/137Cs was calculated to be 2.7×10–4. This ratio was very close to the value expected for fallout from nuclear tests.

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Abstract  

Analytical method for the determination of129I and127I in environmental samples has been developed by using radiochemical neutron activation analysis. The129I levels in the samples such as soil (0.9–41 mBq/kg), precipitation (0.002–0.11 mBq/kg), pine needles (1.2–32 mBq/kg) and seaweed (<0.1–17 mBq/kg) collected near the nuclear facilities in Tokaimura were higher than those from the other areas in Japan. The highest129I concentration was found in surface soil (0–5 cm), and the highest129I/127I ratios were found in pine needles and precipitation. The129I/127I ratio was higher in rice paddy soil than those in wheat field soil collected around Tokaimura, while the concentration of129I somewhat higher in wheat field soil.

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Since 1962, we have been investigating the levels of239,240Pu in human tissues. In the 1960s, the quantities of239,240Pu found in the gonad and spleen were higher than those in liver and lung, as reported in our previous papers. This work was done to provide a reassessment of239,240Pu distribution among several tissue samples from the 1960s and early 1970s, using current analytical techniques for plutonium. The autopsy tissues were collected from the Hospital of Niigata Prefectural Institute for Cancer Research in Northern Japan from 1968 to 1975. The subjects were at least 50 years old at the time of death. The accuracy and precision of239,240Pu determinations were examined using NBS-SRM 4352 human liver samples. Our results are consistent with certified values.

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