• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.12
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• pp.1098-1125
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• 2000

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 1998 and 1999 has been done. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environment. The conclusions are as follows. 1) A review of the recent studies on fluid flow, turbomachinery and pipe-network shows that many experimental investigations are conducted in applications of impingement jets. Researches on turbulent flows, pipe flows, pipe-networks are focused on analyses of practical systems and prediction of system performance. The results of noise reduction in the turbomachinery are also reported. 2) A review of the recent studies on heat transfer analysis and heat exchanger shows that there were many papers on the channel flow with the application to the design of heat exchanger in the heat transfer analysis. Various experimental and numerical papers on heat exchanger were also published, however, there were few papers available for the analysis of whole system including heat exchanger. 3) A review of the recent studies on heat pump system have focused on the multi-type system and the heat pump cycle to utilize treated sewage as the heat source. The defrosting and the frosting behaviors in the fin-tube heat exchanger is experimentally examined by several authors. Several papers on the ice storage cooling system are presented to show the dynamic simulation program and optimal operation conditions. The study on the micro heat pipes for the cooling of high power electronic components is carried out to examine the characteristics of heat and mass transfer processed. In addition to these, new type of separate thermosyphon is studied experimentally. 4) The recent studies on refrigeration/air conditioning system have focused on the system performance and efficiency for new alternative refrigerants. New systems operating with natural refrigerants are drawing lots of attention. In addition to these, evaporation and condensation heat transfer characteristics of traditional and new refrigerants are investigated for plain tubes and also for microfin tubes. Capillary tubes and orifice are main topics of research as expansion devices and studies on thermophysical properties of new refrigerants and refrigerant/oil mixtures are widely carried out. 5) A review of the recent studies on absorption cooling system shows that numerous experimental and analytical studies on the improvement of absorber performance have been presented. Dynamic analysis of compressor have been performed to understand its vibration characteristics. However research works on tow-phase flow and heat transfer, which could be encountered in the refrigeration system and various phase-change heat exchanger, were seemed to be insufficient. 6) A review of recent studies on duct system shows that the methods for circuit analysis, and flow balancing have been presented. Researches on ventilation are focused on the measurement of ventilation efficiency, and variation of ventilation efficiency with ventilation methods by numerous experimental and numerical studies. Furthermore, many studies have been conducted in real building in order to estimate indoor thermal environments. Many research works to get some information for cooling tower design have been performed but are insufficient. 7) A review on the recent studies on architectural thermal environment and building mechanical systems design shows that thermal comfort analysis is sitting environment, thermal performance analysis of Korean traditional building structures., and evaluation of building environmental load have been performed. However research works to improve the performance of mechanical system design and construction technology were seemed to be insufficient.

• Tuberculosis and Respiratory Diseases
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• v.42 no.5
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• pp.685-694
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• 1995

Introduction: Transthoracic fine needle aspiration biopsy(TNAB) has shown to be a resonably safe, simple, and accurate procedure in diagnosis of intrathoracic lung lesions. We reviewed the results of 1,005 TNAB of chest lesions performed on 930 patients with 20 or 22-gauze needles over a period of 10 years. Methods: From November 1983 to June 1995, 1,005 cases in 930 patients with an undiagnosed lung lesion underwent TNAB at the Hanyang University Hospital: 66% were men and 34% were women. Most of the patients were 40~60 years old and the youngest patient was 3 years of age. Result: 540 patients had various malignant chest lesions and 322 patients had benign pulmonary lesions. The diagnostic accuracy of TNAB was 96.1 percent in malignant diseases with one false positive result and 90.1% in benign diseases. A definitive diagnosis was not obtained in the remaining 68 patients. The most common diagnoses among 519 malignancy chest lesions with TNAB were the following: squamous cell lung carcinoma, 31.7%; adenocarcinoma, 24.7%; small cell lung carcinoma, 16.7%; metastatic cancer, 14.2%; large cell lung carcinoma, 6.2% and so on. Complications included pneumothorax in 12.3% necessitating chest tube drainage in 0.6%. Minor hemoptysis occurred in 3.6%. There was no death directly attributable to the procedure. Conclusion: We concluded that TNAB permits a direct approach to all kinds of localized lung lesions with a high degree of accuracy and without major complications.

• Tuberculosis and Respiratory Diseases
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• v.52 no.2
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• pp.156-165
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• 2002

Background: A tracheal stenosis is caused by mucosal ischemic injury related to a high cuff pressure ($P_{cuff}$) of the endotracheal tube. In contrast, aspiration of the upper airway secretion and impaired gas exchange due to cuff leakage is related to a low $P_{cuff}$. To prevent these complications, the $P_{cuff}$ should be kept appropriately because the appropriate $P_{cuff}$ appears to change according to the patient's daily respiratory mechanics. However, the constant cuff volume($V_{cuff}$) has frequently been instilled to the cuff balloon on a daily basis to maintain the optimal $P_{cuff}$ instead of monitoring the $P_{cuff}$ directly at the patients' bedside. To address the necessity of continuous $P_{cuff}$ monitoring, the change in the $P_{cuff}$ was evaluated at various $V_{cuff}$ levels on a daily basis in patients with long-term mechanical ventilation. The utility of mercury column sphygmomanometer for the continuous monitoring $P_{cuff}$ was also investigated. Method: The change in $P_{cuff}$ according to the increase in $V_{cuff}$ was observed in 17 patients with prolonged endotracheal intubation for mechanical ventilation for 2 week or more. This maneuver measured the change in $P_{cuff}$ daily during the mechanical ventilation days. In addition, the $P_{cuff}$ measured by mercury column sphygmomanometer was compared with the $P_{cuff}$ measured by an automatic cuff pressure manager. Results : There were no statistically significant changes of $P_{cuff}$ during more than 14 days of intubation for mechanical ventilation. However the $V_{cuff}$ required to maintain the appropriate $P_{cuff}$ varied from 1.9 cc to 9.6 cc. In addition, the intra-individual variation of the $P_{cuff}$ was observed from 10 $cmH_2O$ to 46 $cmH_2O$ at constant 3 cc $V_{cuff}$. The $P_{cuff}$ measured by the bedside mercury column sphygmomanometer is well coincident with that measured by the automatic cuff pressure manager. Conclusion: Continuous monitoring and management of the $P_{cuff}$ to maintain the appropriate $P_{cuff}$ level in order to prevent cuff related problems during long-term mechanical ventilation is recommended. For this purpose, mercury column sphygmomanometer may replace the specific cuff pressure monitoring equipment.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.6
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• pp.521-537
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• 2012

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2011. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends of thermal and fluid engineering have been surveyed as groups of fluid machinery and fluid flow, thermodynamic cycle, and new and renewable energy. Various topics were presented in the field of fluid machinery and fluid flow. Research issues mainly focused on the rankine cycle in the field of thermodynamic cycle. In the new and renewable energy area, researches were presented on geothermal energy, fuel cell, biogas, reformer, solar water heating system, and metane hydration. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer, nanofluids and industrial heat exchangers. Researches on heat transfer characteristics included heat transfer above liquid helium surface in a cryostat, methane hydrate formation, heat and mass transfer in a liquid desiccant dehumidifier, thermoelectric air-cooling system, heat transfer in multiple slot impinging jet, and heat transfer enhancement by protrusion-in-dimples. In the area of pool boiling and condensing heat transfer, researches on pool boiling of water in low-fin and turbo-B surfaces, pool boiling of R245a, convective boiling two-phase flow in trapezoidal microchannels, condensing of FC-72 on pin-finned surfaces, and natural circulation vertical evaporator were actively performed. In the area of nanofluids, thermal characteristics of heat pipes using water-based MWCNT nanofluids and the thermal conductivity and viscosity were measured. In the area of industrial heat exchangers, researches on fin-tube heat exchangers for waste gas heat recovery and Chevron type plate heat exchanger were implemented. (3) Refrigeration systems with alternative refrigerants such as $CO_2$, hydrocarbons, and mixed refrigerants were studied. Heating performance improvement of heat pump systems were tried applying supplementary components such as a refrigerant heater or a solar collector. The effects of frost growth were studied on the operation characteristic of refrigeration systems and the energy performance of various defrost methods were evaluated. The current situation of the domestic cold storage facilities was analyzed and the future demand was predicted. (4) In building mechanical system fields, a variety of studies were conducted to achieve effective consumption of heat and maximize efficiency of heat in buildings. Various researches were performed to maximize performance of mechanical devices and optimize the operation of HVAC systems. (5) In the fields of architectural environment and energy, diverse purposes of studies were conducted such as indoor environment, building energy, and renewable energy. In particular, renewable energy and building energy-related researches have mainly been studied as reflecting the global interests. In addition, various researches have been performed for reducing cooling load in a building using spot exhaust air, natural ventilation and energy efficiency systems.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.1
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• pp.94-131
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• 2007

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2004 and 2005 has been done. Focus has been put on current status of research in the aspect of heating, cooling, air-conditioning, ventilation, sanitation and building environment. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation of facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat, humidity was also interesting for comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing topics. Well developed CFD and flow visualization(PIV, PTV and LDV methods) technologies were widely applied for developing facilities and their systems. (2) The research trends of the previous two yews are surveyed as groups of natural convection, forced convection, electronic cooling, heat transfer enhancement, frosting and defrosting, thermal properties, etc. New research topics introduced include natural convection heat transfer enhancement using nanofluid, supercritical cooling performance or oil miscibility of $CO_2$, enthalpy heat exchanger for heat recovery, heat transfer enhancement in a plate heat exchanger using fluid resonance. (3) The literature for the last two years($2004{\sim}2005$) is reviewed in the areas of heat pump, ice and water storage, cycle analysis and reused energy including geothermal, solar and unused energy). The research on cycle analysis and experiments for $CO_2$ was extensively carried out to replace the Ozone depleting and global warming refrigerants such as HFC and HCFC refrigerants. From the year of 2005, the Gas Engine Heat Pump(GHP) has been paid attention from the viewpoint of the gas cooling application. The heat pipe was focused on the performance improvement by the parametric analysis and the heat recovery applications. The storage systems were studied on the performance enhancement of the storage tank and cost analysis for heating and cooling applications. In the area of unused energy, the hybrid systems were extensively introduced and the life cycle cost analysis(LCCA) for the unused energy systems was also intensively carried out. (4) Recent studies of various refrigeration and air-conditioning systems have focused on the system performance and efficiency enhancement. Heat transfer characteristics during evaporation and condensation are investigated for several tube shapes and of alternative refrigerants including carbon dioxide. Efficiency of various compressors and expansion devices are also dealt with for better modeling and, in particular, performance improvement. Thermoelectric module and cooling systems are analyzed theoretically and experimentally. (5) According to the review of recent studies on ventilation systems, an appropriate ventilation systems including machenical and natural are required to satisfied the level of IAQ. Also, an recent studies on air-conditioning and absorption refrigeration systems, it has mainly focused on distribution and dehumidification of indoor air to improve the performance were carried out. (6) Based on a review of recent studies on indoor environment and building service systems, it is noticed that research issues have mainly focused on optimal thermal comfort, improvement of indoor air Quality and many innovative systems such as air-barrier type perimeter-less system with UFAC, radiant floor heating and cooling system and etc. New approaches are highlighted for improving indoor environmental condition as well as minimizing energy consumption, various activities of building control and operation strategy and energy performance analysis for economic evaluation.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1983.05a
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• pp.11.2-11
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• 1983

Vocal nodules and polyps are much more frequent in singers, public speakers, teachers and actors. Voice trauma and voice misuse, at times associated with mild inflammatory reaction, appear to be important in their etiology. It is generally agreed that vocal cord nodules and polyps are inflammatory in nature and they arise in the subepithelial layer of loose connective tissue of the vocal cord. Since the junction of anterior and middle thirds of the membranous cord and has the greatest amplitude of vibration. This is the site of predilection for vocal cord nodules. The author performed laryngomicrosurgery for 70 cases of vocal nodules and polyps at Ewha Womans University Hospital during the period of 5 years. The result obtained were as follows ; 1) Surgical excision is not necessarily the best approach because vocal nodules in the early stages will resolve with the simplest voice therapy. 2) In children, surgery is rarely indicated because most nodules in children regress during adolescence. 3) For patients who use their voices professionally, voice therapy is indicated for three months. 4) If after three month of conservative treatment the cord lesion does not improve and the patient it still dissatisfied with his voice, laryngomicrosurgery can then be considered. 5) The small cuffed endotracheal tube in the interarytenoid space helps to keep the cords immobile and in an abducted position. 6) Removal of the nodule shoule be started by gentle retraction posteriorly and as soon as a tear appears anterior to the nodule. 7) On occasion it is preferable to start the dissection with a siccle knife while the nodule is held on the stretch. 8) Voice rest should be maintained for a week following which the free edges of the cords are usually healed.

• Journal of the Korean Vacuum Society
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• v.17 no.4
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• pp.322-330
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• 2008

The properties of discharge, luminance, and spectroscopy are investigated in a longitudinal and transverse discharge fluorescent lamps with tube of outer diameter 4 mm. The sample lamps are prepared to be three kinds of gas composition such as mercury lamps of Ne(95%)+Ar(5%)+Hg(2 mg), the mercury-free lamps of Xe 100% and Ne+Xe(4%). The gas pressure is in the range of $5{\sim}300\;Torr$. In the mercury lamps, the longitudinal discharge having a positive column is high in luminance and efficiency, while the transverse discharge is no luminance at all. In the Xe-lamps, the transverse discharge shows relatively good in efficiency as compared with the longitudinal discharge which has a high discharge voltage and a low luminance and efficiency. In the transverse discharge of relatively high efficiency, a pure Xe(100%) gas discharge has a higher efficiency than the mixture gas of Ne+Xe(4%). Through these experiments, the properties of mercury and xenon lamps are verified. In the mercury lamps, the longitudinal discharge of tubular fluorescent lamps is high in luminance and efficiency, while the transverse discharge of flat panel fluorescent lamps are low in luminance efficiency. In the mercury-free lamps, the flat fluorescent lamps of transverse discharge having a high pressure ${\sim}100\;Torr$ with the pure Xe-gas are verified to be suggestable.

• Korean Journal of Plant Resources
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• v.15 no.3
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• pp.237-242
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• 2002

Loaves, stems, cotyledons, and roots of Hovenia dulcis Thunb grown in test tube were cultured on media containing different concentrations of single or combined growth regulators. In MS media containing 2mg/ι BA, the shoot formation rate was 95.5% and it was the highest frequency of shoot formation. MS media showed most efficiency in the shoot formation at 0.01mg/ι TDZ for the callus formation, but the color of callus changed to brown at a higher concentration of TDZ. Callus formation was 89.% at 0.5mg/ 2.4-D, but IAA, IBA, and NAA were not effective on the formation of callus. Calli were formed only on wound area when IAA, IBA, and NAA were added into MS media. Combined growth regulators (BA + auxin) were more effective in roots and nodes than leaves and cotyledons on the formation of shoot. More than 97％ of shoot formation was obtained on MS media containing BA and auxin. For the production of multiple shoot, nodes of Hovenia dulcis were used and effect of growth regulators on the formation of multiple shoot was evaluated on MS media. Highest shoots (5.3) of Hovenia dulcis were induced on MS media supplied with 0.1mg/ι BA and 0.1mg/ι NAA, and an average of 6.4 shoots per explant were obtained in 1/2 MS media containing same concentration and growth regulators. An average of 7 shoots per explant after 4 weeks of culture from nodes of Hovenia dulcis was produced on a woody plant medium(WPM) containing 0.1mg/ι BA and 0.1mg/ι NAA. Shoot length was 6.0 cm in average.

• Korean Journal of Microbiology
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• v.42 no.3
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• pp.185-194
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• 2006

The aim of this study was to identify the bacteria isolated from endodontic lesions by cell culture and to determine the antimicrobial susceptibility of them against 8 antibiotics. The necrotic pulpal tissues were collected from 27 infected root canals, which were diagnosed as endodontic infection. Samples were collected aseptically from the infected pulpal tissue of the infected root canals using a barbed broach and a paper point. The cut barbed broaches and paper points were transferred to an eppendorf tube containing $500{\mu}l\;of\;1{\times}PBS$. The sample solution was briefly mixed and plated onto a BHI-agar plate containing 5% sheep blood. The agar plates were incubated in a $37^{\circ}C$ anaerobic chamber for 2 to 5 days. The bacteria grown on the agar plates were identified by comparison of 16S rRNA gene (rDNA) sequencing method at the species level. To test the sensitivity of the bacteria isolated from the infected root canals against 8 antibiotics, minimum inhibitory concentrations (MIC) were determined using broth dilution assay. The data showed that 101 bacterial strains were isolated and were identified. Streptococcus spp. (29.7%) and Actinomyces spp. (21.8%) were predominantly isolated. The 9 strains were excluded in antimicrobial susceptibility test because they were lost during the experiment or were not grown in broth culture. The percentage of bacteria susceptible for each antibiotic in this study was clindamycin, 87.0% (80 of 92); tetracycline, 75.0% (69 of 92); cefuroxime axetil, 75.0% (69 of 92); amoxicillin + clavulanic acid (5:1), 71.7% (66 of 92); penicillin G, 66.3% (61 of 92); erythromycin, 66.3% (61 of 92); amoxicillin, 44.6% (41 of 92); and ciprofloxacin, 31.5% (29 of 92). The susceptibility pattern of 8 antibiotics was dependent on the host of the bacteria strains rather than the kinds of bacterial species. These results indicate that antibiotic susceptibility test should be performed when antibiotics are needed for the treatment of infected root canals.

• Tuberculosis and Respiratory Diseases
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• v.63 no.1
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• pp.59-66
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• 2007

Background: Surgical lung biopsy is required to establish the etiology and stage of interstitial lung disease(ILD). and this procedure can be safe and meaningful for making clinical decisions. We wanted to determine the safety of surgical lung biopsy(SLB) in patients with interstitial lung disease(ILD). Methods: We conducted a retrospective review of 40 patients with suspected ILD and they underwent surgical lung biopsy from January 2001 to June 2006 at Chungnam University Hospital. We analyzed retrospectively according to their age, gender, pulmonary function, chest tube duration, the arterial blood gases, the procedural technique, and the requirement for supplemental oxygen and mechanical ventilation(MV) at the time of SLB. Results: The mean age of the patients was 56.4${\pm}$16.13 years(range: 21 to 77 years). Overall, the 30-day and 90-day mortality rates were 15% and 20%, respectively. The predictors of perioperative mortality were either the need for mechanical ventilation(MV) at the time of SLB or the need for supplemental oxygen prior to undergoing SLB. Among the 32 patients who were 90-day survivors, the proportion of those patients using the oxygen supplement was 28.1% (n=9). All 8 patients who were 90-day non-survivors used oxygen supplement (p=0.000). The use of the MV was 12.5% (n=4) in the 90-day survivors (n=32) and 62.5% (n=5) in the 90-day non-survivors (n=8); there was a significant difference between the 90-day survivors and non-survivors (p=0.000). Conclusion: Patients who require MV and supplemental oxygen are associated with an increased risk for death following SLB.