According to recent trends, nonspherical shape optical elements is more required by optical instrument is going miniaturization and high-precision. Nonspherical shape optical elements is made by die. So, die is required high-precision. It requires grinding by fine grain . This experiment purpose making fixed abrasive by fine grain . This has subject that fine grain is condensing. The subject can clear by method of PELID. But, this way has new subject. It is repulsion. The method of PELID is using electricity for spraying fine grain . And it has electricity. It hinder spraying next fine grain . So, I propose spraying with changing electricity direction. By this way can be laminating fine grain and making fixed abrasive.

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According to recent trends, nonspherical shape optical elements is more required by optical instrument is going miniaturization and high-precision. Nonspherical shape optical elements is made by die. So, die is required high-precision. It requires grinding by fine grain . This experiment purpose making fixed abrasive by fine grain . This has subject that fine grain is condensing. The subject can clear by method of PELID. But, this way has new subject. It is repulsion. The method of PELID is using electricity for spraying fine grain . And it has electricity. It hinder spraying next fine grain . So, I propose spraying with changing electricity direction. By this way can be laminating fine grain and making fixed abrasive.

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The silica powder is now commonly used as a kind of abrasives. Besides, the silica powder reacts with the slaked lime under saturated steam pressure to form the calcium silicate hydrate, which is expected to be utilized as a binder for the .
The authors, therefore, investigated here to find out whether these two characterististics of the silica powder were available for manufacturing the .
The followings are the results obtained;
1) The made by this process gave sufficiently good quality for practical use.
2) The variations of the mix ratio of slaked lime to silica powder, the curing pressure, the molding pressure and the fineness of silica powder gave various values of Rockwell hardness, compressive strength, pore size distribution and quality of abrasion. For example, it was possible to decrease Rockwell hardness and the compressive strength by decreasing the mix ratio of slaked lime to silica powder, while the pore volume was increased.
3) The best quality of abrasion was achieved at the curing pressure of 15kg/cm².
4) The mix ratio of slaked lime to silica powder by weight gave considerably good quality of abrasion in the range from 1 : 3 to 1 : 6.
5) By increasing the molding pressure, Rockwell hardness was increased, while the abrasion ratio of to iron piece was decreased.
6) By increasing Blaine specific surface of silica powder, Rockwell hardness, and the abrasion loss of and iron piece were decreased.
7) Mixing of carborundum was effective for the improvement of the quality of abrasion.

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According to recent trends, nonspherical shape optical elements is more required by optical instrument is going miniaturization and high-precision. Nonspherical shape optical elements is made by die. So, die is required high-precision. It requires grinding by fine grain . This experiment purpose making fixed abrasive by fine grain . This has subject that fine grain is condensing. The subject can clear by method of PELID. But, this way has new subject. It is repulsion. The method of PELID is using electricity for spraying fine grain . And it has electricity. It hinder spraying next fine grain . So, I propose spraying with changing electricity direction. By this way can be laminating fine grain and making fixed abrasive. Furthermore, by combining the laminate shaping technique which can control in the thickness direction using Green sheet, it is possible to disperse abrasive grains in the grinding wheel in three dimensions. We have developed a grinding wheel dispersed nano- diamond in three dimensions using this technique

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By the processing such as optics and electronic parts, accuracy of finishing and quality of the processing side controls the performance. Therefore these processing precision have been severe recently. It is effective to use a minute abrasive as one of the technique to improve processing aspect quality by grinding, but there is a problem of the blocking. One of the methods to solve this problem includes ELID grinding. This method is the technique that dressing does while processing a side and enable the use of the using the super minute abrasive of around several nanometers. However, the using the abrasive of around several nanometers has difficulty in dispersion of the abrasive in bond materials. Therefore we build the technique to make a to scatter uniformly the super minute abrasives using the PELID technology and can go ahead through the examination for the purpose of realizing a highly precise processing side of optics, electronic parts. In this report, we produced the PELID device to scatter abrasives and investigated dispersion properties of the liquid with this device and the abrasive.

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Global competition adds to intensity in manufacturing industry year by year these days. Reduction of the production cost and shortening of the delivery date in this way become the important problem for a company. The use of the 3D printer is considered as this one solution. Therefore we aim at the development of the grinding wheel for the laboratory of ELID cuts which on-demand can produce which does not need a die by developing the production technology that put 3D printer and droplet discharge technology PELID together and push forward a study. In this report, I investigated the characteristics including the electrolysis dressing characteristic of the conductivityTPU resin to use for the production of 3D printer and thecomposition production device of the by the PELID technology and 3D printer aiming at the production of the on-demand .

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We conducted elemental analysis on several kinds of excavated natural whetstones and Owari-Shippo enamel ware at the Owari Clan Upper Mansion Site using X-ray Fluorescence (XRF) analysis. The minor element concentrations of two types of excavated tuff are consistent with those used for polishing Owari-Shippo.

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Our ultimate goal is to develop an automatic polishing system that uses an industrial robot equipped with whetstones. The robot mimics the movements skilled workers make as they polish surfaces manually. This paper, the first step in the development of our system, presents experimental results to prove that our system completely removes the marks, which is the most time-consuming and crucial process for human workers, from the flat surfaces of metallic molds produced through the Electrical Discharge Machining (EDM) process. We build a polishing system that consists of a small 6-DOF industrial robot for material handling. Attached to its wrist is a six-axis force-torque sensor and it employs a

holding mechanism. Before the robot system begins its polishing work, the normal force to be applied to the flat surface can be adjusted to a target value by altering the height of the hand. We adopt two polishing paths for the , reciprocating and zigzag. We then conduct experiments using the two paths, visually inspect the surface, and measure the surface roughness and shape. Based on the experimental results, we confirm that the system has completely removed the EDM mark layer. Although we find that the zigzag path leaves striped patterns on the polished surface, we are not able to determine their cause. Finally, we test three combinations of the two paths under different conditions to find the most suitable combination.

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The present study, consisted of two separate surveys, was initiated to clarify the development of clinical pictures of silicosis after termination of dust exposure. The first survey was a 40-year follow-up of radiographic pictures of the chest among 200 male cutters (Group I workers). The second survey was conducted in 75 male recipients (Group II workers) of disability compensation for silicosis due to dust exposure. The study on Group I workers made it clear that the proportion of those free of radiographic findings in the chest pictures decreased during a 40-year follow-up period from 84% in the 1st health examination in 1952-6 to 36% in the 3rd examination in 1995. The rate of progression of the disease from Category 1 to 3 (after ILO-guided classification) to higher categories in a 15-year period was as high as >50%. Longer service duration and higher category of chest radiography at the previous health examination were the influential factors in determining the rapid progression of silicosis. The latter observation was confirmed also through a similar analysis on Group II workers. preparations contained SiO₂ by about 50%. No industrial hygiene data were available for both groups of stone cutters, but the exposure of Group I workers was estimated to be about 1 mg/m³, or well in excess of the current occupational exposure limit.

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The Fe-Al intermetallic compounds have a high hardness and superior resistance against a wear, a heat and an oxidation. Therefore it is expected that the compounds will be used as a tool material and a high temperature structural material for a chemical plant, a turbine, a catalyst and so on. The main purpose of this study is to clarify the abrasion characteristic of the Fe-Al intermetallic compounds. In this study, the elastic of the gelatin base is used as an abrasive stone. Gelatin can control the hardness and a melting point by density, cooling method, cooling time and additives easily. Accordingly a gelatin base stone can produce an elasticity having various characteristics experimentally. In this study, a new elastic made of gelatin having new abrasion mechanism is produced experimentally, and the fundamental abrasion characteristic of the Fe-Al intermetallic compound is examined. The main results obtained are as follows. The elastic produced experimentally can polish the Fe-Al intermetallic compound. Further the surface roughness of the Fe-Al intermetallic compound is improved in a short time so that abrasion speed is fast.

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A seroprevalence study of bovine lentivirus, known as bovine immunodeficiency virus (BIV), was conducted in 12 different dairy herds in Hokkaido, where some herds were a high prevalence of bovine leukemia virus (BLV) infection. Amongst 611 cattle, 28.6% of cattle were BLV-seropositive, and 11.7% of cattle were seropositive for BIV, while 4.2% of cattle were seropositive for both BIV and BLV. For the isolation of BIV, 19 samples of peripheral blood mononuclear cells (PBMC) and one sample of milk-derived leukocytes were prepared from BIV-seropositive cows. These PBMC and leukocyte preparations were then co-cultivated with cc81 cells, a cat cell line transformed by mouse sarcoma virus. BIV was isolated from 17 PBMC and one milk-derived leukocyte samples. The isolated viruses showed slow replication and syncytia formation. Major core antigen, p26 from these isolates were reacted with anti-BIV (American isolate R-29) serum. In addition, proviral DNA was detected in blood and milk samples by nested polymerase chain reaction and subsequent Southern blot hybridization. Nucleotide sequence analysis of the amplified pol gene products showed its 99.0 to 99.7% homology to that of BIV R-29. These results indicate that the Japanese BIV isolates appear to be antigenically and genetically similar to the American R-29. Since BIV was isolated from milk samples, BIV could possibly be transmitted through milk. This is the first report of BIV isolation in Japan.

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近年，加工形状の複雑化に伴い，工具干渉の問題が顕在化している．そこで，マイスナー効果やピンニング効果などの超伝導現象を利用した磁気浮上工具が考案された．超伝導により磁石を空中で回転させることが可能なため，磁石を工具として用いれば工具干渉を低減した新加工技術に応用できると考えた．超伝導による磁石の固定力の計測結果を用いて行った研削・研磨加工の結果について報告する．

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This study aims at the construction of a robotic system that can precisely grind metal molds instead of skilled persons. For example, in case of plastic products like cellular phones, the surface-roughness must be from about 0.1 to 0.03 micrometers. Usually, it takes seven to eight hours for rough grinding and two to three hours for finishing grinding even if a skilled person grinds, which costs a lot of money. Development of an automatic grinding system will reduce the costs. Therefore, the goal of this study is to develop such a system. We use an industrial robot with six joints, and soft and ceramic to grind molds. We conducted some basic experiment and found that the robot can grind the mold as smooth as human to some extent.

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In this paper, impact fracture behavior of circular disks, which are made of or plaster, is discussed experimentally. The fracture phenomena of a disk being dropped on to a rigid plate are photographed for many disks which have various values of ratio a/b (a is the inner radius and b is the outer one.) From these pictures, the cracks appearing in the disks are classified in to several patterns. Next, the stresses developed in the impacted disk are visualized by using the dynamic photoelastic technique. By observing the maximum tensile-stress at the inside or outside surface of the disk, the fracture mechanism of the brittle disks can be estimated.

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The objective of the present study was to examine if the mortality due to tuberculosis and cancer in the lungs was elevated in a cohort of 200 male cutters. 1955-1995 death certificatebased mortality data on the cohort were available, and the data were reviewed in the present study for mortality due to the two diseases to calculate standardized mortality ratios (SMR) in reference to the health statistics of Kyoto prefecture, where the cohort lived. Among the 200 cohort members, 99 men deceased during the observation period, the deaths including 10 cases of lung tuberculosis (of which 9 cases had silicosis together), 20 cases of all malignancies, and 6 cases of lung cancer (5 cases with silicosis). There was a significant elevation in the mortality due to lung tuberculosis (SMR=3.47) although SMR for all causes was not elevated (1.10). There was no significant change in SMR for all malignancies (0.78), whereas SMR for lung cancer (1.24) tended to be elevated although insignificantly. Lung tuberculosis was a significant complication of silicosis in 1955-1995. Possible elevation in lung cancer SMR among this cohort needs further studies.

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Nine 3-month-old rabbits were inoculated with bovine immunodeficiency-like virus (BIV) to study the pathogenesis of BIV and alteration of the immune responses in experimentally infected rabbits. BIV proviral DNA and anti-BIV antibodies were detected from all rabbits inoculated with BIV-infected bovine embryo spleen (BESP) cells. Rabbits inoculated with spleen cells of the BIV-infected rabbit also converted to proviral DNA-positive and BIV-antibody-positive. The blastogenic responses to concanavalin A of peripheral blood mononuclear cells prepared from BIV-infected rabbits were not signifi antly different from those from uninfected controls at 2 and 4 months post-inoculation (PI). The humoral immune responses against bovine serum albumin (BSA) were depressed in two of four BIV-infected rabbits at 1 to 3 months PI. The antibody responses against sheep red blood cells (SRBCs) were significantly depressed in all BIV-infected rabbits at 2 to 4 months PI. BIV was rescued by cocultivation of spleen cells of infected rabbits with BESP cells. Distinct development of lymphoid follicle was observed in lymph nodes and spleens of uninfected rabbits which received BSA and SRBCs. In contrast, moderate lymphoid cell depletion was observed in BIV-infected rabbits which received the same immunogens.

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カメラ付携帯電話等のレンズ部にはIRCFという光学部品が搭載される．カメラの小型化・高画質化に伴い，そこに使用するガラス基板には高い表面精度と形状精度が要求される．従来法である研磨加工は優れた仕上げ加工法であるが職人技と長時間を要する．そこで本研究では，固定砥粒研磨法としてEPD砥石を用いた光学ガラスの超精密研磨に挑戦し，研磨用EPD砥石の開発と加工評価を行い，光学ガラスを高能率に精密加工する手法を開発した．

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