巻号一覧
9 巻 (1992)
- 3 号 p. 101-
- 2 号 p. 53-
- 1 号 p. 1-
9 巻, 1 号
選択された号の論文の6件中1～6を表示しています
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中前 栄八郎1992 年 9 巻 1 号 p. 1-6
発行日: 1992年
公開日: 2012/08/27
ジャーナル フリーEver since Sketchpad proposed by I. Sutherland in 1962, computer graphics have been drastically developing and making efficient use in many fields; not only in science and engineering but also in economics and psychology.
This paper introduces computer graphics viewed from scientific visualization especially on environmental assessment of outdoor-scenes, interactive visualization of magnetic fields, and observation of the internal structure of a complex, multilayered, three-dimensional object.抄録全体を表示PDF形式でダウンロード (2905K) -
Michiaki SAGAE, Eiichi SATO, Teiji OIZUMI, Yutaka OHTA, Hiroshi SEINO, ...1992 年 9 巻 1 号 p. 7-14
発行日: 1992年
公開日: 2012/08/27
ジャーナル フリーA method for generating repetitive flash x rays using a compact cold-cathode triode in conjunction with a two-stage Marx pulser is described. This flash x-ray generator consisted of the following essential components: a high-voltage power supply with a maximum voltage of 100 kV, an energy storage condenser of 97 nF, a modified two-stage Marx pulser with a capacity during the main discharge of 425 pF, a turbo molecular pump, a triggering circuit, and a flash x-ray tube. The two ceramic condensers were charged from 40 to 60 kV, and the output voltages from the high-voltage pulser were about 1.9 times the charged voltage. The x-ray tube was of the triode type which was connected to the turbo molecu1ar pump with a pressure of 6.7×10-4 Pa and consisted of the following major devices: a rod-shaped long anode tip made of tungsten, a ring-shaped trigger electrode made of brass, a cylindershaped cathode electrode made of graphite, and an acrylate resin tube body. The durations of the flash x-ray pulses were about 1μs, and the x-ray intensity with a charged voltage of 60 kV was about.79μC/kg at 0.5m per pulse. The repetitive rate(stable region)was less than 20Hz, and the maximu0m size of the focal spot was equivalent to the anode diameter of 3.0 mm.抄録全体を表示PDF形式でダウンロード (1753K) -
Eiichi SATO, Teiji OIZUMI, Yutaka OHTA, Hiroshi SEINO, Yoshiharu TAMAK ...1992 年 9 巻 1 号 p. 15-22
発行日: 1992年
公開日: 2012/08/27
ジャーナル フリーThe fundamental studies for generating repetitive flash x rays using a glass-enclosed triode with a plate target are described. This generator consisted of the following essential components: a constant positive high-voltage power supply with a maximum voltage of +100 kV, an energy storage condenser of 97 nF, a cable condense of 1.05 nF, a constant negative high-voltage power supply for supplying an initial trigger voltage of -7.0 kV, a repetitive trigger device, and an x-ray tube. The xray tube was of the glass-enclosed triode and consisted of the following major devices: a plate target made of tungsten, a rod-shaped graphite cathode, a mesh-type trigger electrode made from tungsten wires, an insulator made from an acrylate resin tube, and a tube body made of glass. The cable condenser was charged from 30 to 80 kV, and the electric charges in the condenser were discharged to the x-ray tube repetitively when a negative pulse with a maximum voltage of about -15 kV (no-Load) was input (added) to the trigger electrode. The maximum tube voltage was equivalent to the initial charged voltage of the cable condenser, and the maximum tube current was about 0.3 kA with a charged voltage of 60kV. Tbe x-ray durations were about 1μs. and the x-ray intensity was about 0.34μC/kg at 0.5 m per pulse with a charged voltage of 60 kV. The repetitive rate of the flash x rays was less than 100 Hz.抄録全体を表示PDF形式でダウンロード (3311K) -
Eiichi SATO, Shingo KIMURA, Arimitsu SHIKODA, Teiji OIZUMI, Yutaka OHT ...1992 年 9 巻 1 号 p. 23-31
発行日: 1992年
公開日: 2012/08/27
ジャーナル フリーThe fundamental studies of the repetitive type of flash x-ray generator utilizing an enclosedtype diode with a ring-shaped graphite cathode for soft radiography are described. This generator consisted of the following essential components: a constant high-voltage power supply, an energy storage condenser of 97 nF, a high-voltage pulser with a repetitive trigger device, and a flash x-ray tube. The pulser employed a modified two-stage Marx circuit with a capacity during main discharge of 425 pF. The x-ray tube was of the enclosed-diode type and consisted of the following major devices: a rodshaped anode tip made of tungsten, a ring-shaped cathode made of graphite, an x-ray window made of beryllium, a spattering shield made of stainless steel, and a tube body made of glass. The two condensers in the pulser were charged from 50 to 70 kV, and the output voltages were about 1.8 times the charged voltages. Both the peak tube voltage and the peak tube current increased according to increases in the condenser charged voltage, and the maximum values of the voltage and the current were about 80 kV and 0.6 kA, respectively. The pulse widths were less than 100 ns, and the maximum xray intensity was about 1.0μC/kg at 0.5 m per pulse. The repetitien rate(frequency)was less than 20Hz, and the maximum size of the focal spot was nearly equivalent to the anode diameter of 3.0 mm.抄録全体を表示PDF形式でダウンロード (3779K) -
石田 隆行, 山下 一也, 滝川 厚1992 年 9 巻 1 号 p. 32-40
発行日: 1992年
公開日: 2012/08/27
ジャーナル フリーThere are some methods to classify bone atrophy, when a doctor diagnoses osteoporosis by viewing radiographic films. In this study, with digital image processing, we evaluated trabecular patterns quantitatively by spectrum analysis of patterns on the lateral view of lumbar vertebrae.
Radiographs of patients were analyzed with 2-dimensional fast Fourier transform (2DFFT) and 1-dimensional maximum entropy method (1DMEM). The results indicated that we can evaluate the patterns by power spectra with 2DFFT and 1DMEM. Our method offers useful information for the diagnosis of osteoporosis.抄録全体を表示PDF形式でダウンロード (1291K) -
樋口 清伯, 橋本 栄一郎1992 年 9 巻 1 号 p. 41-48
発行日: 1992年
公開日: 2012/08/27
ジャーナル フリーA coding of a multi-valued image with no distortion has became an important problem in the cases of storing many radiographs and other images. This paper describes image coding methods for data compression of a multi-valued image (256 levels) under the constraint to be no distortion.
In this paper arithmetic coding is used, because it is one of coding system realizes the compression with no distortion. The compression rate is lowered near the entropy of Shannon and processing time is increased with the linear order of a number of symbol.
Generally multi-valued image is a gathering of subimages. For example a part of character, a part of figure, a part of picture and so on. So if multi-valued image is divided usefully into subimages. They have same characteristics with respect to information theoretic views and are compressed rapidly to the entropy of subimage.
This paper describes two methods of dividing multi-valued image into subimage using upper plane information. One is lengthwise division method and the other is the method that divides an image into 8 planes. And each method is done in the case of adaptive and non adaptive scheme. Using now method the compression rate is lower than the compression of convention method.抄録全体を表示PDF形式でダウンロード (1898K)
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