• Journal of Korean Institute of Industrial Engineers
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• v.23 no.1
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• pp.115-127
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• 1997

A GDHS(Geothermal District Heating System) is a heating system supplying a group of districts with heat extracted from geothermal sources. The advantages of GDHS include saving fuel consumption as well as reducing air pollution. This paper presents a case study for the economic feasibility model and analysis of a GDHS with which central/individual heating systems are replaced. Configuring to a simplified GDHS which consisits of subsurface systems, surface systems, and transmission/distribution systems, we find out the properties of the system and the model parameters affecting the initial investment/operating costs in order to develop a classical economic feasibility model given geothermal temperature. Based on our model parameter space, we analyzed the geothermal development project of the Jejoo Island probabilistically given prior information such as the expected geothermal power, the demand size and the length of transmission/distribution pipes.

• Journal of Advanced Marine Engineering and Technology
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• v.11 no.1
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• pp.63-71
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• 1987

The measuring of acoustic intensity has been investigated by many researchers and practicians during the last several decades. But due to the lack of measurement accuracy, they have had no practical use. In recent years, the two microphone acoustic intensity method has been developed by the advancement of FFT analysis technique and the digital data processing equipment. This new method of using two microphones gives informations on the noise source survey and the acoustic power of sound radiation source without the anechoic room. In this paper, theoretical formulae for the two microphone acoustic intensity method and the sound transmission loss are checked. The obtained results for the acoustical enclosure of gas heat pump were compared with the classical field incidence mass law. The surface vibration modes for a panel of enclosure were also estimated.

• Journal of Mechanical Science and Technology
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• v.14 no.5
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• pp.499-507
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• 2000

Smooth shift is one of the key issues in automatic power transmission control systems. However, the torque sensors are too expensive to be used in shift controllers on production vehicles. In order to provide a basic strategy for smooth shifting by using RPM sensors only and in order to accomplish the shift within a designated time, this paper studies detailed characteristics of the smooth shift for clutch-to-clutch shift mechanism. A desired trajectory of slip speed is proposed for smooth acceleration shift defined in this paper. Also the clutch torque needed to achieve this trajectory is derived, and it may be used as a open loop shift control law.

• Nuclear Engineering and Technology
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• v.33 no.2
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• pp.201-208
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• 2001

The high power RF transmission line components are required for transmitting MW level RF power continuously in RF heating and current drive system which heat the plasma and produce plasma current in fusion reactor The liquid stub and phase shifter is proposed as the superior to the conventional stub and phase shifter. Experimental results show that they are reliable and easy to operate compared to the conventional stub and phase shifter. There is no distortion of reflected power during the raising of the liquid level. RF breakdown voltage is over 40kV. Temperature increment of the liquid is expected not to be severe. These results verify that the liquid stub and phase shifter can be used reliably in the high power continuous RF facilities.

• Journal of the Korean Wood Science and Technology
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• v.24 no.1
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• pp.75-80
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• 1996

The purpose of this study is to clarify the mechanism of moisture transfer depend on the thickness of the spruce(Picea sitchensis Carr.). Therefore, as the basic research of moisture transmission, the amount of moisture transmission and the moisture distribution in specimens and temperature of it's surfaces in vapor transmission process were investigated. The experiment was conducted in a steady state. and the moisture distribution was measured by knife cutting and weighing the specimens. The following conclusions were obtained ; 1. It can be found that distribution of moisture in the specimen can be approximated by two different straight lines intersecting at nine or ten percent moisture content. The amount of moisture movement defends on the gradient of moisture in the wood. 2. It is investigated that the wood surface moisture contents(MCs) are less for thinner specimens than for thick ones on the absorption side. On the other hand, the wood surface MCs are greater for thinner specimens than for thick ones on the desorption side. The main factor that affects the EMC of wood would be temperature when the relative humidity of atmosphere is constant. The specimen generate heat with the absorption and desorption process. In addition, the velocities of moisture transmission varied with the thicknesses of specimens. If the temperature of wood becomes greater, its MC decreases. Then the difference between surface MC and EMC of adsorption and desorption side becomes greater for thinner specimens. Therefore it is considered that the coefficients of moisture transfer decreases with the increases of the specimens' thicknesses.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.707-714
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• 2003

Plasma Arc Curing(PAC) units operate at relatively high intensity and claimed to result in optimum properties of composite resin in a short curing time, so the interest of pediatric dentists about PAC units have been increased recently. But PAC units used for polymerizing restorative resins produce heat during operation. The purpose of this study was to evaluate temperature transmission through dentin of various depths using two types of PAC units(Flipo, Q-Lux plasma 100). The results from the present study can be summarized as follows : 1. When PAC be used continuously, temperature on tip was increased as curing times, and Q-Lux showed greater temperature rising(p<0.001). 2. Compared temperature transmission as dentin depth, temperature rising rate was decreased as dentin thickened(0.5, 1.0, 1.5, 2.0mm)(p<0.05). 3. Compared temperature transmission as resin depth, temperature rising rate was also decreased as resin thickened(1.0, 2.0mm)(p<0.05).

• Composites Research
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• v.34 no.1
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• pp.63-69
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• 2021

In order to develop an integrated heat dissipating material and gas barrier film for electronics, new polymer was designed and synthesized for preparing composites containing hexagonal boron nitride (hBN) filler. Depending on the size and content of the hBN filler, both thermal conductivity and oxygen transmission rate can be adjusted. The composite achieved a high thermal conductivity of 28.0 W·m-1·K-1 at most and the oxygen transmission rate was decreased by 62% compared to that of the filler free matrix. Effective filler aspect ratios could be estimated by comparing thermal conductivity and oxygen transmission rate with values predicted by theoretical models. Discrepancy on the aspect ratios extracted from thermal conductivity and oxygen transmission rate comparisons was also discussed.

• The Korean Journal of Physiology and Pharmacology
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• v.27 no.1
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• pp.39-48
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• 2023

Spinal nerve injury causes mechanical allodynia and structural imbalance of neurotransmission, which were typically associated with calcium overload. Storeoperated calcium entry (SOCE) is considered crucial elements-mediating intracellular calcium homeostasis, ion channel activity, and synaptic plasticity. However, the underlying mechanism of SOCE in mediating neuronal transmitter release and synaptic transmission remains ambiguous in neuropathic pain. Neuropathic rats were operated by spinal nerve ligations. Neurotransmissions were assessed by whole-cell recording in substantia gelatinosa. Immunofluorescence staining of STIM1 with neuronal and glial biomarkers in the spinal dorsal horn. The endoplasmic reticulum stress level was estimated from qRT-PCR. Intrathecal injection of SOCE antagonist SKF96365 dose-dependently alleviated mechanical allodynia in ipsilateral hind paws of neuropathic rats with ED₅₀ of 18 ㎍. Immunofluorescence staining demonstrated that STIM1 was specifically and significantly expressed in neurons but not astrocytes and microglia in the spinal dorsal horn. Bath application of SKF96365 inhibited enhanced miniature excitatory postsynaptic currents in a dosage-dependent manner without affecting miniature inhibitory postsynaptic currents. Mal-adaption of SOCE was commonly related to endoplasmic reticulum (ER) stress in the central nervous system. SKF96365 markedly suppressed ER stress levels by alleviating mRNA expression of C/ EBP homologous protein and heat shock protein 70 in neuropathic rats. Our findings suggested that nerve injury might promote SOCE-mediated calcium levels, resulting in long-term imbalance of spinal synaptic transmission and behavioral sensitization, SKF96365 produces antinociception by alleviating glutamatergic transmission and ER stress. This work demonstrated the involvement of SOCE in neuropathic pain, implying that SOCE might be a potential target for pain management.

• Journal of Microbiology and Biotechnology
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• v.4 no.1
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• pp.30-35
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• 1994

A varient strain of budding yeast, Hansenula anomala B-7 which had been identified to be highly resistant to cadmium ions, were observed by transmission electron microscopy. It was shown that the cells accumulated excess amounts of cadmium ions throughout inside the cell rather than on the cell surface. The cell growth in response to cadmium or heat shock stress has also been investigated. It was observed that the cells precultured in the presence of 500 $\mu$ g/ml of Cd ions grew slower than those precultured at 1, 000 $\mu$ g/ml of the metal ions, when they were cultivated in the media containing 1, 000 $\mu$g/ml of the metal ions. Heat shock, however, stimulated the cell growth transiently, when the cells were allowed to grow in the presence of 1, 000 $\mu$g/ml of the metal ions. But the cells given heat shock for more than 100 min received permanent damage to growth. Effects of both stresses on budding rate was also examined. It revealed that the stresses did not change the budding ratio much, which was contradictory to that observed from the same budding yeast, Saccharomyces cerevisiae. Furthermore, the cells treated with 1, 000 $\mu$g/ml of the metal ions not only induced, but also switched off the expression of several new proteins. Some of the cadmium stress-inducible proteins were estimated to be also induced by heat shock stress.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.2
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• pp.232-237
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• 2011

Recently, continuous research on cryogenic valves is being carried out with the rapid development of the cryogenic valve-related industry, and especially, high performance of cryogenic valves is being promoted due to the breakthrough development and demand of users, etc., of the mechanical, shipbuilding, semiconductor and display industry and the aerospace industry field, but it is the reality that technical development and research on cryogenic application equipment on vacuum insulation are insufficient. The present research focused on interception of heat exchange with the outside by keeping low pressure after installing a jacket pipe outside a stem and also considered heat transfer properties on changes in pressure of a vacuum part and radius of a jacket which can reduce heat exchange for effective heat transmission control by studying it in a three-dimensional numerical analysis method.