• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1710-1716
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• 2008

The Loop Heat Pipe (LHP) operates to pump the working fluid by means of the capillary force in a wick structure. Particularly, it is difficult to design and manufacture the evaporator consisted of a grooved container and a compensation chamber as well as the wick structure. This study is related to design and manufacture the grooved container coupled with wick structure, the properties of the wick structure such as the permeability, the porosity, and the maximum capillary pressure were measured to apply the cooling technology for Insulated Gate Bipolar Transistor (IGBT). The container of the LHP was manufactured by the electrical discharge process and the wick structure was sintered with the nickel particle by an axial-press apparatus with the pulse electronic discharge. As results, the properties of the wick were experimentally obtained about 60% of the porosity, 35kPa of the maximum capillary force and $1.53{\times}10-13m2$ of the permeability.

• Journal of Environmental Health Sciences
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• v.45 no.3
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• pp.203-212
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• 2019

Objective: A total of five students at same middle school were reported to be diagnosed with pediatric leukemia (n=2), non-Hodgkin's lymphoma (NHL, n=1) and aplastic anemia (n=2) between 2016 and 2017. The aims of this study are to assess exposure to environmental hazardous agents known to be associated with the risk of leukemia and to examine whether the environment of school is associated with the risk leukemia. Method: A total of 11 environmental agents causing childhood leukemia were monitored using international certified method in schools where patients had ever attended. Radon & Thoron detector was used to monitor real-time airborne radon and thoron level ($Bq/m^3$). Clinician interviewed two among nine patients who agreed to participate in this study in order to examine the association of demographic and genetic factors by individually. Leukemia, NHL, and aplastic anemia were grouped into lymphohematopoietic disorder (LHP). Results: Except for airborne radon level, no environmental agents in school and household where patients may be exposed were found to higher than recommended airborne level. Clinical investigation found no individual factors that may be associated with the risk of LHP. Higher airborne radon level than Korea EPA's airborne radon criteria ($148Bq/m^3$) was monitored at most of several after-class room of one elementary school, where two leukemia patients graduated. Significant radon level was not monitored at class-room. Significant exposure to radon of patients was not estimated based on time-activity pattern. Conclusions: Our results have concluded that there have been no environmental factors in school and household environment that may be associated the risk of LHP.

• Proceedings of the SAREK Conference
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• 2003.07a
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• pp.65-65
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• 2003

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.96.1-96
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• 2001

This paper is shown that the impulse and unit step response of second-order system can be computed by the analytic methods using Laplace transform. Also, the transient response specifications are explicitly formulated by the peak undershoot and maximum overshoot of the step response. Three different second-order systems are investigated: prototype system, system with LHP(left half plane) real zero, and system with RHP(right half plane) real zero. Based on these analytic results, this paper presents the sufficient and necessary conditions for the second-order linear SISO(single-input/single-output) stable system to have the nonovershooting or monotone nondecreasing step response.

• Journal of ILASS-Korea
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• v.7 no.2
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• pp.31-36
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• 2002

According to the improvement of PC performance, it is expected that calorific value, which causes PC to malfunction, is increased. Therefore, the development of new cooling system is recently required. As the method to solve this problem, we applied loop heat pipe to PC cooling system. The advantage of the loop heat pipe is that it has a small size, light weight, simple shape, long life and it has a good performance on heat transfer, no-noise, wide range of applicable temperature and no supply of power from the outside. It is confirmed that loop heat pipe reduces thermal resistance and has a good performance on PC cooling.

• The Korean Journal of Zoology
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• v.37 no.3
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• pp.377-384
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• 1994

The present study examines the inhibitow effect of progesterone (P) on luteinizing hormone $(LH)\beta$ subunit gene expression in anterior pituitary of ovariectomized, estradiol-treated adult rats. A single injection of P (1mg) further decreased the estradiol-Induced decrease in $LH\beta$ mRNA levels in ovariectomTzed rats in a time-dependent manner. p suppressed UIP mRNA levels at lower doses (0.1 and 1mg), but increased $LH\beta$ mRNA levels 81 a high dose (toms). The inhibitor action of P on $Uf\beta$ mRNA was restored when Ru486, a P receptor antagonist, was administered 1h before P treatment. These data clearly indicate that P inhibits gene expression of $LH\beta$ in the rift pituitary in a swersic manner with estrogen.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2137-2143
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• 2008

This paper investigates the plate loop heat pipe system with an evaporator mounted with fin-wick structure to dissipate effectively the heat generated by the electronic components. The heat transfer formulation is modeled and predicted through thermal resistance analysis of the fin-wick structure in the evaporator. The experimental approach measures the thermal resistances and the operating characteristics. These results gathered in this investigation have been used to the objective of the information to improve the LHP system design so as to apply as the future cooling devices of the electronic components.

• Journal of Mechanical Science and Technology
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• v.19 no.4
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• pp.1052-1061
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• 2005

A small-scale loop heat pipe (LHP) with polypropylene wick was fabricated and tested for investigation of its thermal performance. The container and tubing of the system were made of stainless steel and several working fluids were tested including methanol, ethanol, and acetone. The heating area was $35\;mm\;{\times}\;35\;mm$ and nine axial grooves were provided in the evaporator to provide vapor passages. The pore size of the polypropylene wick inside the evaporator was varied from $0.5\; {\mu}m\;to\;25\;{\mu}m.$ The inner diameter of liquid and vapor transport lines were 2.0 mm and 4.0 mm, respectively and the length of which were 0.5 m. The size of condenser was $40\;mm\;(W)\;{\times}\;50\;mm\;(L)$ in which ten coolant paths were provided. Start-up characteristics as well as steady-state performance was analyzed and discussed. The minimum thermal load of $10\;W\;(0.8\;W\;/cm^{2})$ and maximum thermal load of $80\;W\;(6.5\;W\;/cm^{2})$ were achieved using methanol as working fluid with the condenser temperature of $20^{\circ}C$ with horizontal position.

• 한국균학회소식:학술대회논문집
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• 2016.05a
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• pp.17-17
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• 2016

Calcineurin governs stress survival, sexual differentiation, and virulence of the human fungal pathogen Cryptococcus neoformans. Herein, we identified and characterized calcineurin substrates in C. neoformans by employing phosphoproteomic $TiO_2$ enrichment and quantitative mass spectrometry. The identified targets include the zinc finger transcription factor Crz1 and proteins whose functions are linked to P-bodies/stress granules (PBs/SGs) and mRNA translation and decay, such as Pbp1 and Puf4. We show that Crz1 is a bona fide calcineurin substrate, and localization and transcriptional activity of Crz1 are controlled by calcineurin. Several of the calcineurin targets localized to PBs/SGs, including Puf4 and Pbp1, and are required for survival at high temperature and for virulence. Genetic epistasis analysis revealed that Crz1 and the novel targets Lhp1, Puf4, and Pbp1 function in a branched calcineurin pathway that orchestrates stress survival and virulence. These findings propose that calcineurin controls thermal stress and virulence at the transcriptional level via Crz1 and post-transcriptionally by regulating target factors involved in mRNA metabolism.

• Journal of the Society of Naval Architects of Korea
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• v.59 no.4
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• pp.225-234
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• 2022

The flow field measurement above whole area of the flight deck on 'Landing Platform Helicopter (LPH)' was performed by using PIV system in wind tunnel. In various heading angle conditions (0deg, -30deg, -45deg, -60deg, -75deg and ±90deg), the velocity fields such as U velocity & V velocity were measured at three different height above flight deck. Due to the geometrical characteristics of several bodies like deck, crane and super-structure, various vortex were generated. When the heading angle is 0deg, the deck edge vortex by flight deck and massive separation by super-structure were clearly observed by visualization with smoke and PIV, respectively. In other heading angles, the acceleration of flow in space between crane and super-structure were detected. And area with flow separation by super-structure is directly related to the heading angle of vessel.