• The Korean Journal of Zoology
• /
• v.7 no.2
• /
• pp.25-36
• /
• 1964

The present paper deals with the comparative study on phylogenic difference in the patterns of energy metabolism of brain slices of several vertebrate species by measuring oxygen consumptionwith glucose-6-phosphate, glucose-1-phosphate, glyceraldehyde-3-phosphate or glutamate as respiratory substrate employing Warburg's manometric method, by determination of the utilization rate of glucose using glucose-1-C14 by analyzing patterns of free amino acid distribution , and by histochemical determination using glucose-1-C14 by analyzing patterns of free amino acid distribution acid distribution , and by histochemical determination of glycogen contents. 1. Glucose enhances the oxygen consumption of brain slices of animals belinging to reptile, aves and mammalia while it shows a tendency to decrease that of animals belonging to pisces and amphibia. 2. Glucose-6--phosphate increase oxygen consumption more than glucose in every species examined, while glucose-1-phosphate and glyceraldehyde-3-phosphate increase that of Rana nigromaculata only . In general m, it appears that phosphosugars are more effective as a respiratory substrate to those species which have less endogenous respiration than to those having larger endogenous respiration. 3. Similar patterns of free amino acid distribution and the relative amount are found among the species and in every species examined glutamic acid is detected in the larges amount . ${\gamma}$-Amino butyric acid, glycine, alanine and aspartic acid are found in every species. 4. Ophicephalus showed less oxygen consumption than endogenous respiration when glutamate was added to the medium. When sodium fluoride was added, the oxygen consumption was some what increased . Such phenomenon wasnot found in the frog. 5. The result of histochemcial analysis of the brain showed that glycogen was abundantly present in the fish , amphibia , and especially in the reptile and that no distinctive grains of glycogen were found in the bird and mammal . From these facts, it may be supposed that anaerobic glycolysis as energy source dominates in fish and amphibia and aerobic respiration through the oxidation of glucose dominates in bird and mamal , the reptile occupying transitional position between these two categories. The way of obtaining energy for brain activity by the oxidation of glucose supplied from the circulating blood is seemed to be first acquired by reptile and the function is completed both in aves and mammal.

• International Journal of Precision Engineering and Manufacturing
• /
• v.9 no.4
• /
• pp.3-10
• /
• 2008

Micro-electrical discharge machining (micro-EDM) is an effective method for machining all types of conductive materials regardless of hardness. Since micro-EDM is an electro-thermal process, the energy supplied by the pulse generator is an important factor in determining the effectiveness of the process. In this study, an investigation was conducted on the micro-EDM of tungsten carbide (WC) to compare the performance of transistor and resistance/capacitance (RC) pulse generators in obtaining the best quality micro-hole. The performance was measured by the machining time, material removal rate, relative tool wear ratio, surface quality, and dimensional accuracy. The RC generator was more suited for minimizing the pulse energy, which is a requirement for fabricating micro-parts. The smaller-sized debris formed by the low-discharge energy of RC micro-EDM could be easily flushed away from the machined zone, resulting in a surface free of burrs and resolidified molten metal. The RC generator also required much less time to obtain the same quality micro-hole in WC. Therefore, RC generators are better suited for fabricating micro-structures, producing good surface quality and better dimensional accuracy than the transistor generators, despite their higher relative tool wear ratio.

• Journal of the Korean Ceramic Society
• /
• v.23 no.1
• /
• pp.1-6
• /
• 1986

The shrinkage rate of solid state sintering has been theoretically derived by combining the rate equation of material transport and the net free energy change resulting from the decrease of solid-vapor interface and the increase of grain boundary during sintering. For a sinteing model an idealized situation of the spherical particles with BCC packing was taken as the initial condition and the shrinkage was assumed to occur by forming the flat circualr grain boundaries on each particle. The plotted shrinkage rates as a function of grain boundary to surface energy ratio $(gamma_g/gamma_s)$ have shown that the relative density increases linearly at the initial stage of sintering but the shrinkage rate is decreased upon further sintering due to a decrease in driving force for densificaton. It has been also shown that the densification is critically affected by the $gamma_g/gamma_s$ ratio. In order to get the complete densificatin the ratio should be less than $sqrt{3}$. Any additive or atmospheric condition causing the decrease of$_g/gamma_s$ ratio will enhance sintering.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.478-481
• /
• 2009

As a first step for aerodynamic analysis of vertical axis wind turbine, dynamic stall characteristics of airfoil was investigated. Dynamic stall of wind turbine airfoil is caused by severe variation of angle of attack and relative velocity of flow around airfoil. Angle of attack and relative velocity can be expressed with tip speed ratio. Variation of angle of attack is strongly dependent on the tip speed ratio. For tip speed ratio, 1.4 and free stream velocity, 15m/s, dynamic stall characteristics of wind turbine airfoil is compared with those of oscillating airfoil having same angle of attack variation.

• Journal of Welding and Joining
• /
• v.18 no.1
• /
• pp.104-109
• /
• 2000

Based on the principle of complementary energy, an analytical method is developed which focused on the end effects for determining thermal stress distributions in the clad beam. This method gives the stress distributions which completely satisfy the stress-free boundary condition at the edge. Numerical results shows that shear and peeling stress at the interface between the substrate and clad are significant near the edge and become negligible in the interior region. Even thought the relative location where the maximum or minimum stresses take place moves to interior as the length of the beam becomes smaller, the absolute location from the free end and the value of these stresses are the same in spite of the variation of the length of beam.

• Proceedings of the KWS Conference
• /
• 1999.10a
• /
• pp.306-309
• /
• 1999

Based on the principle of complementary energy, an analytical method is developed which focused on the end effects for determining thermal stress distributions in the claded beam. This method gives the stress distributions which completely satisfy the stress-free boundary condition at the edge. Numerical result shows that shear stress and peeling stress at the interface between the substrate and clad are significant near the edge and become negligible in the interior region. Even though the relative location where the maximum or minimum stresses take place moves to interior as the length of the beam become smaller, the absolute location from the free end and the value of these stresses are the same in spite of the variation of the length of beam.

• Structural Engineering and Mechanics
• /
• v.21 no.2
• /
• pp.169-184
• /
• 2005

This study deals with the free vibration of a circular plate in contact with a fluid; submerged in fluid, beneath fluid or on fluid. An analytical method based on the finite Fourier-Bessel series expansion and Rayleigh-Ritz method is suggested. The proposed method is verified by the finite element analysis using commercial program with a good accuracy. The normalized natural frequencies are obtained in order to estimate the relative added mass effect of fluid on each vibration mode of the plate. Also, the location of plate coupled with fluid and the cases of free and bounded fluid surface are studied for the effect on the vibration characteristics.

• Bulletin of the Korean Chemical Society
• /
• v.27 no.12
• /
• pp.2028-2036
• /
• 2006

The combined ab initio and vibrational predissociation (VP) spectroscopic studies on methylammonium-$(water)_4$ complex aimed at understanding the hydration behavior of an amphiphilic ion core are described. The ab initio calculations predicted eleven low-energy isomers forming cyclic, tripod, chain, and caged structures, and their relative stabilities, total hydration energies and thermodynamic functions at 298 K and 150 K. The excellent correlation between the observed VP spectra and ab initio spectra for bonded N-H, bonded O-H and free O-H stretches suggested co-existence of five cyclic isomers and two non-cyclic isomers in ion beam at 150 K, consistent with the trends of calculated Gibbs free energies.

• Journal of Nutrition and Health
• /
• v.27 no.4
• /
• pp.323-335
• /
• 1994

The present study was carried out in normocholesterolemic New Zealand white(NZW) rabbit, to evaluate the effect of dietary supplementation with Korean pinenut oil, on plasma lipids, plasma lipoproteins, liver lipids and platelet aggregation. NZW rabbits were fed for 80 days on a commercial chow diet supplemented with 5% of energy as fats(soybean oil or pinenut oil) or 10% of energy as fats(soybean oil or pinenut oil). A control group was fed a commercial stock diet. There were no significant effects of pinenut oil on plasma free cholesterol, HDL-cholesterol, triglycerides, glucose and lecithin-cholesterol acyltransferase, as compared with those obtained from rabbits fed the soybean oil diet. After 80 days, the concentration of plasma free fatty acid in only the pinenut oil group was significantly decreased by about 50% relative to the control diet. At the end of the dietary treatment, liver triglycerides and phospholipids were significantly decreased in the pinenut oil group, compared to the how diet, whereas the soybean oil-consuming rabbits had only significantly decreased phospholipid levels. Cholesterol contents of liver were unaffected by type of dietary fat. At the end of 80 days, a diet containing pinenut oil resulted in a decrease in apolipoprotein B and the apo B/apo AI ratio as compared with the stock diet or soybean oil diet. Platelet aggregation induced by collagen or arachidonic acid was depressed significantily in pinenut oil diet.

• Korean Journal of Microbiology
• /
• v.5 no.2
• /
• pp.79-85
• /
• 1967

Kim, Jong Hyup., (Div. of Biology, Atomic Energy Research Institute,Korea.;) Studies on the Cellulor Metabolism in Microorganisms as influenced by Gamma-irradiation(III): On the Changes of Free Amino acid Pool and content of Protein in Yeast clls irradiated by .gamma.-ray. 1. The strain of Saccharomyces cerevisiae had been cultured synchronously in aerobic condition and irradiatel by gamma-ray from the source of cobalt-60. Drying in vacuum oven at $90^{\circ}C$ C over 12 hours, then changes of protein content (Kjeldahl) and free amino acid pool have been assayed with use of spectrophotometer. Results obtained were compared with those of unirradiated normal cells. 2. It is proved that amount of protein content in the irradiated cells increases to seven percent more than those of normal cells in the same weight of dried samples. It seems like carbohydrate breakown had been stimulated by irradiation and that relative contents of protein shows higher values than those of normal in the same weight of samples. 3. The amount of free amino acid pool in the irradiated cells shows less value about ten percent than those of normal cells, and rate of decreasing is also weak than those of standard reagent solution of amino acid. We may assume that free amino acid pool would be protected against radiation damage in living cells and more stable than in vitro. 4. The component of free amino acid pool have been assayed on second dimensional paper chromatogram, and the identified amino acids are as follows; aspartic acid, serine, glutamic acid, cystine, lysine, glycine, threonine, histidine, arginine, tyrosine, phenylalanine, valine and leucine. 5. Distributional presence of free amino acids are identical to that of normal cells except arginine, it is cosumable that radiation effect is univerlsal to all amino acid. However it is obvious that there are differences in radiolabilities of amino acids in irradiated cells.