• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.9 no.4
• /
• pp.504-516
• /
• 1997

Recently scientists and engineers are developing a system to get waste heat of low-temperature level with advanced heat pump, which have not been used up to now. As the reason, it is necessary to examine capability of using waste heat which is raised up in the tunnel of subway out of widely distributed low-temperature waste heat in large cities. Therefore we surveyed thermal environment of the tunnel of subway in $S\check{o}my\check{o}n$, downtown of Pusan, from November 1995 to December 1996 and developed a program to predict the thermal environment of subway on the basis of experimental data and the geometries of tunnels. This paper has proved availability of waste heat of subway when the measured results obtained in subway in the winter time and the simulated results of thermal environment prediction program are compared, as well as has reported results of estimating reliability of the simulation program. As the result, the charateristics of thermal environment in the tunnel of subway in $S\check{o}my\check{o}n$ station in the winter time are to be followed; 1) temperature in the tunnel is about $10^{\circ}C$ higher than outside air temperature, 2) temperature change in the tunnel is less than that in the platform so that we may obtain stable heat source, 3) and when the measured results obtained in subway in the winter time and the simulated results of thermal environment prodiction program is compared, both results show similar tendency. Therefore, we confirm estimating reliability of the simulation program.

• Journal of the Korean Society for Heat Treatment
• /
• v.19 no.5
• /
• pp.280-286
• /
• 2006

• Transactions of the Korean Society of Automotive Engineers
• /
• v.5 no.5
• /
• pp.9-19
• /
• 1997

In this paper, the modeling and analysis of dynamic characteristics has been carried out for friction clutches and brakes in an automatic transmission. From the operating oil pressure generated by the valve-body, time delay by check valve and the movement of piston has been examined. Also torque capacity and torque transferred at the clutch is studied. Heat capacity and temperature distribution at the reaction plate of clutch are codeled by time-dependent, nonhomogeneous partial differential equation, and brake torque, brake time, and the amount of heat generated are investigated. It is found that the time delay at the check valve is very short but dominant at the spool.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2000.04a
• /
• pp.75-78
• /
• 2000

There are several effective factors to influence die life in the warm forging process. For instance process design die design and die materials etc This study presented heat treatment method which could improve toughness and wear resistance simultaneously in high temperature to apply high speed tool steels like SKH51 to die material for warm forging process. To verify the feasibility of application of heat treatment method mentioned above wear test was performed under the condition of constant time in 40$0^{\circ}C$ Wear coefficient was examined to search a relation between wear amount and time for each material and heat treatment method in 30, 60, and 130 minutes. To quantify the toughness-behavior between room and high temperature impact test was performed and heat fatigue test also fulfilled to compare with the resistance of heat check in room, 200, 400, and $600^{\circ}C$ temperature. On the basis of experimental results mentioned above high speed tool steel was applied to verify appropriateness of newly proposed heat treatment method for die of rotor pole used in automobile alternator. As a result die life of high speed tool steel applied newly proposed heat treatment is longer than that of STD61.

• Plant Journal
• /
• v.6 no.1
• /
• pp.71-75
• /
• 2010

In this study, the validity study has been carried out to apply the combustion burner in an electric arc furnace. The validity of applying the combustion burner has been studied in the aspect of the operation through the calculation of heat balance. The average decrease rate of power on time is 11.2%. When the maintainability is compared to the door lance manipulator type, the multi-functional combustion burner is simple to replace and repair. The location of burner can be adopted according to the drawings which are recommended in this study. As a result, the validity of applying the combustion burner to improve an efficiency of electric arc furnace has been confirmed.

• Journal of the Korean Wood Science and Technology
• /
• v.22 no.2
• /
• pp.61-70
• /
• 1994

This study was executed to find the applicability of press drying of tree disk by investigating the shrinkage and drying defect and to form appropriate model by comparing the actual moisture content(MC) and internal temperature in respect of drying time with calculated values based computer simulation to which was applied finite difference method. In press drying disk, heating period, constant drying rate period maintained plateau temperature at 100$^{\circ}C$ and falling drying rate period were significantly distinguished. Actual MC and internal temperature were analogous to those calculated at comparing points. Heat transfer model formed by Fourier's law using specific heat of moist wood and conduction coefficient considering fractional volume of each element of wood cell wall, bound water, free water and air showed applicability as basic data to developing heat expansion, shrinkage and drying stress during press drying. Also mass transfer model formed by Fick's diffusion law using water vapor diffusion coefficient showed applicability. Longitudinal shrinkage was developed by pressure of hot press and tangential shrinkage was restrained by hygrothermal recovery. The heart check, surface check and ring failure were occurred differently in species, but V-shaped crack didn't develop.

• Atmosphere
• /
• v.25 no.4
• /
• pp.707-718
• /
• 2015

This study investigates the characteristics of turbulent fluxes observed at Ieodo Ocean Research Station (IORS) in autumn 2014. The 10 Hz IORS data is quality controlled and calculated to be the 30 minutes turbulent fluxes. The quality control consists of five steps: a weather check, Vickers and Mahrt (VM) sequential check, VM parallel check, flag check, and direction check. Since the IORS is an open-sea station with no orographic influence, there are no significant diurnal variations for the turbulent fluxes and 10 m wind speed. According to stabilities, the unstable and semi-unstable states appear more than 28% and 70% in autumn, respectively and they have strong winds of over $10m\;s^{-1}$. In addition, the turbulent fluxes increase with increasing wind speed. In particular, the latent heat flux and its deviations are clearly shown because the latent heat flux is influenced by the change of both the sea surface roughness and wave height induced by the wind. To demonstrate the changes of the turbulent fluxes before and after typhoon, Vongpong (1419), which is the most intense typhoon affecting the Korean Peninsula in 2014, is considered. The turbulent flux fluctuates in accordance with the location of Vongpong. The turbulent fluxes have a large (small) variation when Vongpong approaches (retreats) at the IORS. The overall results represent that the IORS data helps us understand physical processes related to air-sea interaction by providing the valuable and reliable observed data.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.26 no.2
• /
• pp.19-29
• /
• 2013

Objectives : The main purpose of this study is to investigate the efficiency of Gagamchengyoung-tang (Ji$\bar{a}$ji$\check{a}$nq$\bar{i}$ngy$\acute{i}$ng-t$\bar{a}$ng) and examine the febrile tendency in the alopecia patients Methods : Of the patients who have visited Balmers Korean Medicine clinic for alopecia from December first 2012 to December 31st 2012, we enrolled 30 patients and performed heat and cold diagnosis, examine scalp and check hair density. We administrated Gagamchengyoung-tang(Ji$\bar{a}$ji$\check{a}$nq$\bar{i}$ngy$\acute{i}$ng-t$\bar{a}$ng) and acupuncture to all patients. The effect was assessed by scalp condition and hair density Results : The scalp disorder index decreased and hair density increased in alopecia patients with febrile tendency Conclusions : All patients had febrile tendency and Gagamchengyoung-Tang(Ji$\bar{a}$ji$\check{a}$nq$\bar{i}$ngy$\acute{i}$ng-t$\bar{a}$ng) can be effective in the scalp disorder and alopecia.

• Journal of Korea Foundry Society
• /
• v.26 no.1
• /
• pp.17-26
• /
• 2006

The substitution of cooling method from water quenching to air cooling after solution heat treatment was aimed for the development of a convenient and economical heat treatment process of duplex stainless steels without deterioration of mechanical and corrosion resistant properties for the industry. In order to achieve this goal, the mechanical properties and corrosion properties of a ASTM A890-4A duplex stainless steel were systematically investigated as functions of casting condition and cooling method after solution heat treatment. A 3-stepped sand mold and a permanent Y-block mold were used to check the effects of solidification structure and cooling rate after solution heat treatment. The microstructural characteristics such as the ferrite/austenite phase ratio and the precipitation behavior of ${\sigma}$ phase and carbides were investigated by combined analysis of OM and SEM-EDX with an aid of TTT diagram. Hardness and tension test were performed to evaluate the mechanical properties. Impact property at $-40^{\circ}C$ and corrosion resistance were also examined to check the possibility of the industrial application of this basic study. Throughout this investigation, air-cooling method was proved to effectively substitute for water-quenching process after the solution heat treatment, when the duplex stainless steel was sand mold cast with a thickness below 15 mm or permanent mold cast with a thickness below 20 mm.

• The Journal of Dong Guk Oriental Medicine
• /
• v.5
• /
• pp.33-52
• /
• 1996

The purpose of this study was to investigate efficient treatment in obesity. In order to help clinical application in obesity treatment, this study was performed to investigate the cause and treatment in obesity. The main finding of this study were as follows. 1. In the cause of oriental medicine in obesity, that were moisture(濕), phlegm(痰), gore(瘀), the productive heat(積熱), overeating, supemutrition, underaction, heredity and habitude, psychologic factor(stress) etc. 2. In the western medicine, the cause of obesity were genetic cause, endocrine disorder, hypothalamic extraodinary and secondary effect of drug. But simple obesity is the greater part. Also there were psychologicai and environmental causes. 3. Ear acupuncture of wide application were Naebunbi, Sinmun, Taejang, $ij{\check{o}}m$, $Pyej{\check{o}}m$, $Bij{\check{o}}m$ etc. 4. Body acupuncture of application were $Naej{\check{o}}ng$, $Sangg{\check{o}}h{\check{o}}$, Pungnyung, Kokchi, $Sam{\check{o}}mgyo$, $Umn{\check{o}}ngch{\check{o}}n$ etc. 5. In oriental medical treatment of obesity, Bangpungtongs ngsan(防風通聖散), Daesihotang(大柴胡湯), Seungkitang(承氣湯), Bangkihwangkitang(防己黃?湯), Richulsaryeungtang(二朮四笭湯), Taeksatang(澤瀉湯), Opieum(五皮飮), Gongyundan(控涎丹) etc were wide applicated. 6. The western medical treatment in obesity encourage the dietary cure, exercise cure and behavior adjustment than medical therapy or operation. In treatment of obesity, the dietary cure and herb-drug therapy, ear acupuncture and body acupuncture are effective. But weight maintenance after treating is more important. After all the continuous dietary cure, behavior adjusting cure and exercise cure are necessary.