加速器の真空ダクトの製作に当たっては、ビ!)ムアパ!)チャ!)を確保し、かつ、狭いマグネット空間に挿入することから、高い製作精度が要求される。本報告では、ひずみの発生しやすいアルミ製真空ダクトの加工・溶接組み立工程におけるひずみ発生事例とその修正工程及び溶接組立手順について考察した。

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Welded structures increasingly wide use in resent years, example being their extensive adoption in facilities for studies in high energy physics.
This is attributable to such propertiss of this particular metal as compared with other metal, as being light in weight and possesing high corrosion resistance, as also to its small susceptibility to activation, and its rapid deactivation even upon becoming radioactive.
The piping often used in these structures is thin walled and of small diameter or non-circular sectional figure, which makes it necessary to develop welding techniques adapted to such pipes and automatic welding techniques in particular.
This review is concerned with the promising results obtained in developing a system for one-side butt welding of small size circular or hippodrome cross section pipes using DCSP-TIG process, which ensure deep penetration to actual welding of TRISTAN.
At the National Laboratry High Energy Physics Japan, the TRISTAN; Transposable. Ring Intersecting Storage Acceleratros in Nippon; complex is now under construction.
TRISTAN is designed to accelerate electtron (e^-) and positron (e⁺) to 30GeV and to make them collide head-on to each other, and bring about many new exciting phenomena, as to detect the top quark, heavy leptons, Higg's particle and Z⁰particle.
TRISTAN requires many innovations in the technology such as a super conducting magnet, ultra high vacuum and so on. One of them, the ultra high vacuum chambers made all of aluminum alloy, to be newly developed, are adapted to TRISTAN Accumulator Ring and Main Ring, and the super conducting magnet made all of aluminum alloy is adapted to TOPAZ Thin Solenoid Magnet of TRISTAN detector.
The automatic welding process for small diameter pipe of aluminum is used in constructing these structures. In TRISTAN Accumulator Ring and Main Ring, the automatic welding equiments have been newly developed for hippotrome cross section aluminum pipes.
In TOPAZ Thin Solenoid Magnet, the automatic welding equipment for small diameter aluminum pipe has been used to weld Helium-cooling pipes.
These techiques were applied in practice to weld the assembly joints of these structures. The welding equipments functioned fully as specified, and the resulting joints were of completely satisfactory quality.
Work is now under way in developing auto matic welding techniques to meet new requirements, and in establishing and simlifying the algorithms governing the welding conditions.

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2024-T3 aluminum alloy studs were welded to 6N01-T6 aluminum alloy plates by using an advanced high-speed solid-state joining method. Plastic deformation of a projection was promoted with increasing discharge voltage. As the result, joining area and joint strength increased. Fracture stress was about 300 MPa in all discharge voltage. In the case of thin plate, the outside region was subjected to higher temperature than the inside region, which caused asymmetrical deformation. In contrast, the deformation was symmetrical in the case of thick plate, because temperature similarly rose in both inside and outside. This resulted in the increased joining area and joint strength with increasing plate thickness. Vickers hardness profile was also measured across the weld interface. The softened zone was appeared at the 6N01-T6 aluminum alloy plate adjacent to the weld interface. Hardness of the softened zone was recovered to that of 6N01-T6 aluminum alloy after post-weld aging. This result indicated that softening was caused by dissolving β″precipitates in the aluminum matrix due to the welding heat input.

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A case report of a vascular leiomyoma of the mediastinum is presented. A 47-year-old man was seen to have a right mediastinal mass on chest X-ray film. A thoracic CT scan demonstrated a mass adjacent to the descending aorta. The mass was enhanced after injection of contrast material. Aortography ruled out aneurysm. An angiogram of the intercostal artery demonstrated a highly vascularized mass.
Resection was performed through a standard right posterolateral thoractomy. The tumor was not invasive and had no connection with the esophagus. After the intercostal artery and vein were ligated, the tumor was resected. The size of the tumor was 8×5×5cm. The cut surface of the tumor revealed white tissue with a thin capsule.
Microscopically the tumor consisted of interlacing bundles of spindle cells of uniform size. The bundles also appeared to originate from the wall of the small blood vessels which were distributed throughout the tumor. Neither anaplasia nor cellular pleomorphism was recognized. These findings were compatible with diagnosis benign vascular leiomyoma.
The patient's postoperative course has been uneventful for a year.

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Weldability of Al-Cu series alloy 2219 with MIG process was investigated in comparison with that of Al-Cu-Mg series alloys 2024. On weld cracking sensitivity, 2219 is superior to 2024 and as for the combination with filler metal, the decrease of Mg content in weld metal makes a crack resistance to increase. And a liquation cracking in heat affected zone was easily initiated in case of Mg contents more than 1.6 mass%and Cu/Mg(ratio in mass%) less than 1.8 in weld metal.Welded joints were mostly fractured in weld metal even reinforcement on during tensile testing, so the intensification of weld metal is directly connected with the improvement of joint strength and fractured mode. The results of investigation of correlation between the strength and chemical composition in weld metal revealed that the joint strength increased with an increase of magnesium and manganese but encouraged the weld cracking simultaneously. However the author has also found that silicon was available for decreasing weld crack and the possibility of consistence with joint strength and crack resistance by control of these contents of Mg,Mn and Si.

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前縦隔に平滑筋腫が発生することは非常にまれである.今回我々は, 前縦隔に発生した平滑筋腫の1切除例を経験したので報告する.症例は53歳の男性.検診にて胸部異常陰影を指摘された.胸部CT, MRIで前縦隔に充実性腫瘤を認め, 胸腺腫を疑い, 腫瘍および胸腺の摘出術を施行した.腫瘍は4.0×3.0×2.5cm, 20gで薄い被膜に覆われていた.発生母地は不明であったが, 病理組織学的診断は平滑筋腫であった.術後4ヵ月現在, 再発徴候を認めていない.自験例は前縦隔に発生した平滑筋腫の本邦2例目の報告である.

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最近,新材料の開発が進み,また真空装置の多様化により,種々の新しい材料が真空用として使用しはじめられている. 超高真空装置構造材料として,ルミニウム合金や,イオンプレーティング被覆,高真空材料として繊維強化プラスチックスの利用が試みられている.真空構成材料としては,耐熱性のある高分子材料,セラミックスなどもその特長を生かして,真空装置の性能をさらに高めるために使用されている.

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New type of LNG carrier with independent aluminum tanks of prismatic shape, SPB system (Self-supporting Prismatic Tank Type-B System), was developed in Ishikawajima-Harima Heavy Industries, Co., Ltd.(IHI). This system is specialized by the accurate estimation and guarantee of fatigue strength of aluminum tanks, hence, the stress concentration around welding bead has to be controlled under the allowable value. Though many reports have been made already, especially for design and analytic technologies, welding technologies to accomplish this system have not been reported yet in detail. This paper introduces the technology development on the fillet welding for the aluminum LNG tank. Though the weld beads are grinded by a tool in order to guarantee the fatigue strength in conventional method, new practice to ensure the fatigue strength without grinding was developed by carrying out many experiments and by introducing new automatic welding equipment. In this paper these improvements are reported.

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Penetration mechanisms of welding by continuous wave (CW) YAG laser beam for mild steel were discussed. Bead-on-plate tests were carried out varing laser beam power and welding speed, and the cross-sectional shapes of the welds were measured. The fundamental welding characteristics for mild steel by YAG laser beam were estimated in comparison with those by CO₂ laser beam. The results obtaine are as follows. (1) The penetration mechanism of key-hole welding in a steady state by YAG laser beam agrees with the heat conduction theory for a wedge type volume heat source model, like that by CO₂ laser beam. (2) YAG laser beam has lower threshold power to enter fusion of mild steel and its absorption efficiency is less dependent upon the cavity depth of molten pool than CO₂ laser beam. Then, input power can be controlled to adjust the irradiating beam power, that is necessary to slow down penetration depth at the end of weld.

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　症例は79歳男性で1991年3月にタール便と貧血(Hb6.2)で来院.胃内視鏡検査にて胃角部から幽門部小弯側にかけて3個の悪性病変を認め生検にて未分化型腺癌と診断し胃切除を施行.術後の病理学的検索で悪性血管内皮腫と診断した.さらに5カ月後に下血を来し,大腸内視鏡検査で直腸に出血性ポリープを認めた.ポリペクトミーにて止血したが組織学的所見は胃と同様であった.内視鏡的に盲腸・上行結腸,残胃吻合部に同様の病変を認めた.他の部位には明かな病変はなく,消化管原発と考えられた.消化管に発生する悪性血管内皮腫は非常に希である.今回われわれは消化管に多発した興味ある症例を経験したので文献的考察を加えて報告した.

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気管・気管支平滑筋腫は本邦で31例の報告がなされているまれな疾患である。我々は右上幹に発生した平滑筋腫の1手術例を経験した。症例は66歳の男性, 血痰を主訴として来院。術前気管支鏡下生検にて右上幹原発の気管支平滑筋腫と診断した。右後側方切開法, 第5肋骨床で開胸し, 右上幹管状切除・端々吻合術を施行した。腫瘤は5×4×4mm, 弾性硬。気管支平滑筋より連続性に内腔へ突出した腫瘍は核異型に乏しい長紡錘形細胞が交錯しており, 表面は線毛円柱上皮に被われていた。最終病理診断も気管支平滑筋腫で悪性所見はなかった。自験例を加えた32症例の臨床的検討を加え報告する。

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