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It is significant to measure surface tension and its temperature under microgravity in an ambient atmosphere with various oxygen partial pressures as a function of temperature, from the view point of both industry application and science of high temperature melts. Measurement will be carried out using the electromagnetic levitator on board the Gulfstream., 資料番号: AA0063706002

In order to cultivate plants under low pressure closed environment, germination experiments of white radish were conducted under low pressure experiment, under low oxygen partial pressure experiment, and in pure oxygen experiment. Seeds germinated at more than 8 kPa oxygen partial pressure. At 6 kPa oxygen partial pressure, the germination rates under low pressure and in pure oxygen were higher than that under low oxygen partial pressure. This phenomenon could be related to the diffusion of oxygen molecules., 資料番号: AA0046917042

Time evolution of the Marangoni flow instability and the effect of oxygen partial pressure on the Marangoni convection were studied. Under the hyper-critical condition (Ma greater than 10,000) the Marangoni flow is almost turbulent. Although the flow instability mode is described by the Wanschura's formula at the low Marangoni number using an aspect ratio of As, such as m = 2/As, flow instability mode shows time dependence at high Marangoni number case. The effect of oxygen on growth striation in silicon crystals grown by the floating-zone method was investigated., 資料番号: AA0046917051

資料番号: AA0063158006, レポート番号: JAXA-SP-06-017

Surface-tension-driven flow of molten silicon was investigated under microgravity and on earth for liquid bridge configuration. In order to investigate instability structure in a molten silicon bridge, observed were temperature oscillation and its phase relationship using thermocouples, oscillation of a molten silicon bridge surface using phase shift interferometry, oscillation of melt/solid interface position oscillation and so on. Instability structure shows azimuthal wave number m, depending on an aspect ratio of a liquid bridge: Gamma = h(height)/r(radius). Surface-tension-driven-flow shows oxygen partial pressure dependence of an ambient atmosphere. This is due to oxygen partial pressure dependence of temperature coefficient of surface tension., 資料番号: AA0045947018, レポート番号: NAL SP-56

The two important phenomena to direct the oxidation of brass are the selective oxidation and volatilization of zinc contained in brass. In this report, the oxidation rate of brass was measured in various atmosphere to consider these phenomena. As the results of investigation, it is cmfirmed that the selective oxidation is affected by partial pressure of oxygen in atmosphere, and the dezincification depends on protectability of oxide layer and diffusibility of zinc in atmosphere., 真鍮中の亜鉛の選択酸化性は真鍮の耐酸化性を左右するという意味で，真鍮の高温酸化を規制する主要な条件であることは云う迄もない。従って従来も真鍮の高温酸化については主としてこの点から検討が行われている。しかしながら真鍮の高温酸化を取扱う上には猶今一つの条件として，真鍮中の亜鉛の可成り大きな蒸気圧を考慮に入れる必要がある。というのはこれが揮発による脱亜鉛現象の原因となって，種々の欠陥を生成するからである。例えば通常の焼鈍過程でも，所謂red stainと称せられる欠陥は局部的な脱亜鉛現象に密接な関係を持つと考えられ，又所謂光輝焼鈍では問題は更に重要になる。即ち酸化皮膜の生成を祖止する条件は，又揮発による脱亜鉛にとっても極めて好都合なものであって，この相反する二つの現象を同時に防止することが極めて困難になるからである。真鍮の光輝焼鈍が従来から難しいとされている一つの原因である。このように真鍮中の亜鉛の揮発現象はその選択酸化性と共に，真鍮の加熱効果を左右する主要なfactorであり，之等を規制する条件を検討することが，殊に光輝焼鈍を取扱う上に必要であると考えられる。かかる意味で本報では真鍮の酸化速度に及ぼす加熱雰囲気の影響を調べ，其等の結果から焼鈍過程に於ける真鍮中の亜鉛の選択酸化，揮発現象について二三検討を行った。