A newly designed and constructed experimental apparatus for vaporization and condensation of minerals in the solar nebula.

在原始太阳星云中，气体在高温下凝结成矿物颗粒，固体行星，如地球和陨石都是由这些颗粒的吸积形成的。据认为，固-液反应，如蒸发和冷凝，在化学和矿物分馏的星云中发挥了重要作用。然而，尽管这些反应意义重大，但人们对矿物的蒸发和冷凝的实验研究却很少，特别是对冷凝的实验研究。本研究项目成功地建立了一套实验系统，对原始太阳条件下矿物的蒸发和冷凝进行了研究。在第一年，制造并校准了用于蒸发和冷凝的真空炉（AYUMI EC 300）。一开始，事故多发生在为大型样品室加热而专门设计的加热器部分。第二年，对加热器部分进行了改进和安装，并在模拟太阳成分的Mg_2SiO_4-H_2系统中进行了实验，得到了一些结果。确定了缩合反应的条件，认为缩合反应主要受温度控制，镁橄榄石晶须的生长遵循VLS机理。该炉可对大量样品进行热处理，便于对样品进行SEM、TEM和XRD表征。此外，微量元素和同位素的组成将很容易从大量样品中确定。利用该实验系统的进一步研究将有助于进一步了解原始太阳系。

Condensation of mineral grains from gas at high temperatures took place in the primodial solar nebula, and solid planets, such as the earth, and meteorites were formed by accretion of these grains. It is considered that solid-liquid reactions, such as vaporization and condensation, played an important role in chemical and mineralogical fractionation in the nebula. Irrespective of the significance of the reactions, however, little experimental work has been done especially on condendsation.In the present research project, an experimental system was successively established to study vaporization and condensation of minerals near the primodial solar conditions. In the first year, a vacuum furnace for vaporization and condensation (AYUMI EC300) was made and calibrated. At the beginning, accidents happened usually in a heater part, Hich was specially designed for heating a large sample chamber. In the second year, the heater part was improved and fixed, and several results were obtained from experiments by using this furnace.The experiments were carried out in the system Mg_2 SiO_4 -H_2 , Hich mimics the solar composition. Conditions for the condensation were determined, and it was concluded that the condensation is controlled mainly by temperature and forsterite whiskers can grow by the VLS mechanism. Large amounts of samples can be treated in tghis furnace, and this makes it very easy to charzacterize the samples by SEM, TEM, and XRD. Moreover, the compositions of trace elements and isotopes will be easily determined from large amounts of samples. Further studies using this experimental system will contribute to further understanding of the primodial solar system.