Relative amounts of nuclear deoxyribonucleic acid (DNA) from telophase root tip nuclei and thin-layer chromatographic patterns of alcohol-soluble compounds from dry leaves were determined for seven diploids: Avena clauda, A. pilosa, A. ventricosa, A. strigosa, A. hirtula, A. wiestii, A. longiglumis; four tetraploids: A. barbata, A. magna, A. abyssinica, A. vaviloviana; and four hexaploids: A. sterilis, A. fatua, A. byzantina, and A. sativa, in order to elucidate species relationships. Variation in nuclear DNA content was correlated with differences in genomic constitution; a few exceptions are considered to reflect chromosomal polymorphism. The average DNA value of the hexaploid species approximated the sum of the DNA value for A. magna and the theoretical value of the B genome. Chromatographic patterns showed distinct variations between species but little correlation between number of compounds and DNA content. Chromatographic patterns of hexaploids showed close similarity with those of diploids and tetraploids, except species with modified C genomes (A. clauda, A. pilosa, A. ventricosa) and A. longiglumis. It is considered that A. clauda, A. pilosa, A. ventricosa, and A. longiglumis did not participate in the evolution of polyploid taxa. From their chromatographic profiles, A. wiestii, A. abyssinica, A. vaviloviana, and A. byzantina are very closely related. Both A. magna and the AABB tetraploid species appear to share two genomes in common with the hexaploids. Hence, the genomic constitutions AADD and AABBDD have been proposed for A. magna and the hexaploids, respectively. Six compounds from ethanol leaf extracts of A. sativa were identified as three apigenins, luteolin, ferulic acid, and p-coumaric acid.

Recently, development of a small and high efficient heat exchanger, which is utilized in a fuel battery and a heat pump system for CO 2 refrigerant and so on, is strongly required. In author's previous study, a prototype of stacked high pressure resistance microchannel heat exchanger manufactured with diffusing bond technique has been proposed. In the present study, the objective is to reveal flow and heat transfer properties of this microchannel heat exchanger when water and vapor are employed as low-and high-temperature fluids, respectively. Pressure drop and heat transfer rate are measured as flow and heat transfer properties, respectively. As the results, it is identified that the cross-flow heat exchanger operates as a condenser with small pressure drop of less than 60 kPa. Heat transfer rate of it is approximately 7500 W despite the weight of 240 g. Counter-flow heat exchanger indicates high heat transfer properties as heat transfer rate of approximately 9000 W.

At present, a microchannel heat exchanger is requested to achieve high efficiency in small size energy equipments. In order to clarify the heat transfer mechanism in a microchannel heat exchanger, knowledge on the thermal hydraulic characteristics of condensation flow in channels is essential. However, study on the thermal hydraulic characteristics of steam condensation flow in a microchannel is hardly conducted except visualization of flow patterns. Especially, the number of study on the correlation between the flow structure and heat transfer is small. The objective of the present study is to clarify the thermal hydraulic characteristics of condensation flow in a microtube through the observation of condensation behavior. In order to achieve the purpose, overall heat transfer coefficient in annular flow and slug flow is measured. As the results, the observed flow pattern is transformed from annular flow to bubbly flow through injection flow in a single capillary glassy tube as simulated unit microchannel. And the local overall heat transfer coefficient at slug flow is 10 to 25% lower than that at the annular flow under the particular condition in the present study.

At present, a microchannel heat exchanger is requested to achieve high efficiency in small size energy equipments. In order to clarify the heat transfer mechanism in a microchannel heat exchanger, knowledge on the thermal hydraulic characteristics of condensation flow in the channels is essential. However, study on the thermal hydraulic characteristics of condensation flow in a microchannel is hardly conducted except visualization of flow patterns. Objectives of the present study are to estimate the heat transfer performance of the present device and to observe the condensation behavior of vapor flow to clarify the thermal hydraulic characteristics of condensation flow in a capillary tube. As the results, it is confirmed that the microchannel heat exchanger realizes heat exchange of 7 kW when phase changes. In a single capillary glass tube as a simulated unit microchannel, the annular flow, the injection flow and the bubbly flow in a capillary tube are observed. According to the comparison of the present device and the glass tube experiment, it is suggested that the flow structure in the microchannel heat exchanger is almost same as that in the glass capillary tube.

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