• Journal of the Korean Chemical Society
• /
• v.15 no.6
• /
• pp.347-352
• /
• 1971

The variations of the positive and negative electrode potentials, and of internal pressure were measured during the charge of the sealed type Ni-Cd cell. Both polarization characteristics of a paste type Cd-electrode as a gas diffusion electrode in 30% KOH solution and the effects of active carbon electrode as an oxygen consuming auxiliary electrode of the Ni-Cd cell on the charging characteristics of the cell were studied. Peak voltage at the end of charge of the cell is ascribed to the peak at the negative electrode potential, which is due to the concentration polarization by the lack of $Cd^{++}$ ion and oxygen concentration. And the recovery of the negative electrode potential is resulted from depolarization by the increasing diffusion limiting current density with the increasing oxygen pressure. The active carbon electrode was effective as an oxygen consuming auxiliary electrode. The internal pressure of the cell could be maintained below 200mmHg even at one hour rate charge and overcharge by the use of active carbon electrode as an auxiliary electrode.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.460-465
• /
• 2003

The modeling of PEM (Proton Exchange Membrane) fuel cell system consisting of fuel cell stack and BOP (Balance of Plant) is presented in this paper. The effects of temperature, pressure (air, hydrogen), and humidity on the fuel cell system performance were mainly investigated using thermo-dynamical and electro-chemical equations. To understand the power distribution characteristics of fuel cell system, the effects of operating temperature and air pressure on maximum power and system power were also demonstrated. Through this study, we can get the basic insight into the fuel cell stack and BOP component sizing and it can be used effectively for the optimization of the practical fuel cell systems in purpose.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.10a
• /
• pp.51-54
• /
• 2008

This study aims to devise and analyze a power generation system combining the solid oxide fuel cell and oxy-fuel combustion technology. The fuel cell operates at an elevated pressure, a constituting a SOFC/gas turbine hybrid system. Oxygen is extracted from the high pressure cathode exit gas using ion transport membrane technology and supplied to the oxy-fuel power system. The entire system generates much more power than the fuel cell only system due to increased fuel cell voltage and power addition from oxy-fuel system. More than one third of the power comes out of the oxy-fuel system. The system efficiency is also higher than that of the fuel cell only system. Recovering most of the generated carbon dioxide is major advantage of the system.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.20-20
• /
• 2011

It has been known that, under certain conditions, application of low-temperature atmospheric-pressure plasmas can enhance proliferation of cells. In this study, conditions for optimal cell proliferation were examined for various cells relevant for orthopaedic applications. Plasmas used in our experiments were generated by dielectric barrier discharge (DBD) with a helium flow (of approximately 3 litter/min) into ambient air at atmospheric pressure by a 10 kV~20 kHz power supply. Such plasmas were directly applied to a medium, in which cells of interest were cultured. The cells examined in this study were human synoviocytes, rat mesenchymal stem cells derived from bone marrow or adipose tissue, a mouse osteoblastic cell line (MC3T3-E1), a mouse embryonic mesenchymal cell line (C3H-10T1/2), human osteosarcoma cells (HOS), a mouse myoblast cell line (C2C12), and rat Schwann cells. Since cell proliferation can be enhanced even if the cells are not directly exposed to plasmas but cultured in a medium that is pre-treated by plasma application, it is surmised that long-life free radicals generated in the medium by plasma application stimulate cell proliferation if their densities are appropriate. The level of free radical generation in the medium was examined by dROMs tests and correlation between cell proliferation and oxidative stress was observed. Other applications of plasma medicine in orthopaedics, such as plasma modification of artificial bones and wound healing effects by direct plasma application for mouse models, will be also discussed. The work has been done in collaboration with Prof. H. Yoshikawa and his group members at the School of Medicine, Osaka University.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 1993.10a
• /
• pp.1318-1328
• /
• 1993

Expression of chinese cabbage was conducted in order to investigate its dewatering behavior. Chipped cabbage was packed into cylinder and pressed by piston up to the predetermined pressure on Instron-1000. The rates of dewatering were affected domintantly by the applied pressure, but not significantly by the packed amount of cabbage in the cylinder. The pressure effect was increased very abruptly at first, but the increase rate was very low at high pressure greater than 20 MPa, showing great deviation from linear dependence of flow rate on pressure in Darcy's Law. Therefore, water expression from cabbage was not Newtonian flow of water through cell wall. In fact, the squeezed water contained a lot of solid particles, showing destruction of cell wall. The content of solid particles in expressed water was only slightly lower than the dry matter content of fresh chinese cabbage, determined by drying oven method.

• Journal of the Mineralogical Society of Korea
• /
• v.9 no.1
• /
• pp.35-42
• /
• 1996

Polycrystalline ZrH2 in tetragonal crystal system has been compressed in a modified Bassett-type diamond anvil cell up to 36.0 GPa at room temperature. X-ray diffraction data did not indicate any phase transitions at the present pressure range. The pressure dependence of the a-axis, c-axis, c/a and molar volume of ZrH2 was determined at pressures up to 36.0 GPa. Assuming the pressure derivative of the bulk modulus (K0') to be 4.11 from an ultrasonic value on Zr, bulk modulus (K0) was determined to be 160Gpa by fitting the pressure-volume data to the Birch-Murnaghan equation of state. Same sample was heated at $500^{\circ}C$ at the pressure of 9.8 GPa in a modified Sung-type diamond anvil cell. Unloaded and quenched sample revealed that the original tetragonal structure transforms into a hexagonal structured phase with a zero-pressure molar volume change of ~115.5%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.4
• /
• pp.426-431
• /
• 2004

We have studied the pressure-dependent liquid crystal's dynamics in a twisted nematic (TN) liquid crystal panel with thin film transistor by applying an external pressure to it. When the external pressure is applied to the panel in a dark state, the disclination lines were generated as a light leakage whereas they did not appear in a simple test cell that has only pixel and common electrodes. It was because the disclination lines were Provoked by the electric field between pixel electrode and data/gate bus line for active matrix driving. Consequently, the external pressure resulted in dynamic instability of the liquid crystal so that the disclination lines at the data/gate bus line intruded into the active area.

• YAKHAK HOEJI
• /
• v.31 no.5
• /
• pp.308-314
• /
• 1987

In cardiovascular disease the flow adaptation of erythrocytes can be affected by reduced shear stresses and metabolic influences on red cell fluidity as a consequence of tissue hypoxia. In addition there are indications that risk factors of cardiovascular diseases are able to decrease the intrinsic red cell deformability. Erythrocyte deformability was studied by the filtration technique of Reid et al. to investigate the relationship between blood pressure chances and erythrocyte deformability. In this experiment normotensive rats, spontaneously and DOCA-salt treated hypertensive rats were used. Erythrocyte deformability was significantly reduced by blood pressure elevation in hypertensive rats but was not fully recovered by normalization of blood pressure after antihypertensive drug treatment. Therefore other factors than blood pressure may be involved in erythrocyte deformability reduction during blood pressure elevation.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.39 no.2
• /
• pp.94-99
• /
• 2006

The tadpole larvae of most ascidians have two sensory pigment cells in their brain vesicle. The anterior otolith pigment cell is sensitive to gravity, whereas the posterior ocellus pigment cell responds to light. Besides these two sensory cells, the larvae also possess another type of sensory receptor cell: hydrostatic pressure receptor (Hpr) cells. The Hpr cells have been presumed to sense hydrostatic water pressure, although no functional analysis has been performed. In larvae of the ascidian Halocynthia reretzi, the development of the Hpr cells and their structure in the brain vesicle are poorly understood. To investigate the morphology and formation of the Hpr cells, we established a monoclonal antibody, Hpr-1, that specifically recognizes Hpr cells. The Hpr-1 antigens became detectable in the brain vesicle at the late tailbud stage. Each Hpr cell projected a small globular body, connected by a short stalk, into the lumen of the brain vesicle. The brain vesicle showed remarkable left-right asymmetry. Pigment cells were located on the right side in the lumen of the brain vesicle, whereas Hpr cells were present in the left side. After metamorphosis, the Hpr cells were observed near the rudimental siphons of the juvenile.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.30 no.1
• /
• pp.22-29
• /
• 2008

Purpose: The purpose of this study is to test the efficacy of various methods of fat harvesting in animal model by viability comparison with assay including cell counting, MTT assay, and histologic evaluation. Materials and methods: New Zealand white rabbits experiments were used. Groin fat pads were subjected to different harvest method varying ingredients of solution(Experiment 1: T1 solution= lidocaine 1000mg/L, epinephrine 1mg/L, sodium bicarbonate 10mgEq/L, Triamcinolone 10mgEq/L; T2 solution=lidocaine 1000mg/L, epinephrine 1mg/L, sodium bicarbonate 0mgEq/L, Triamcinolone 0mgEq/L) and pressure exerted on harvesting with Luer-Lock syringe connected to suction cannula.(Experiment 2: P1 group=3cc intermittent pressure; P2 group=10cc sustained pressure) Fat cell viability was assessed with cell counting with a hemocytometer, MTT assay, and histologic evaluation. Results: Experiment 1 Cell count: T1=2.4/3.4/4.2, T2=9.6/8.4/7.2($\times10^5$ per mL); MTT assay: T1=0.516/0.41/0.453/0.412/0.421, T2=0.925/0.765/0.54/0.634/0.614 in 21 days(absorbance); Histology: T1 showed elongated and, different in size and shape, and ruptured adipocytes with only a few normal adipocytes whereas T2 showed central core of fat with almost intact fat cells Experiment 2 Cell count: P1=1.2/3.2/4.2, P2=1.2/2.4/3.8($\times10^5$ per mL); MTT assay:P1=0.256/0.245/0.258/0.21/0.264, P2=0.12/0.231/0.245/0.313/0.281 in 21 days(absorbance); Histology: P1 showed somewhat evenly distributed normal-looking fat cells and P2 showed relatively irregular shape of fat cells with small blood vessel amongst adiopocytes. Conclusion: Viability was higher in ‘modified tumescent solution’without sodium bicarbonate and triamcinolone and we also found no significantly different viability between using intermittent pressure and using sustained pressure. But in terms of initial viability of fat cell, we can assume that lower intermittent pressure would make better clinical results.