• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.6
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• pp.256-268
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• 2016

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2015. 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) The research works on the thermal and fluid engineering were carried out in the areas of flow, heat and mass transfer, cooling and heating, and air-conditioning, the renewable energy system and the flow inside building rooms. Research issues dealing with air-conditioning machines and fire and exhausting smoke were reduced. CFD seems to be spreading to more research areas. (2) Research works on heat transfer area were carried out in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the economic analysis of GHG emission, micro channel heat exchanger, effect of rib angle on thermal performance, the airside performance of fin-and-tube heat exchangers, theoretical analysis of a rotary heat exchanger, heat exchanger in a cryogenic environment, the performance of a cross-flow-type, indirect evaporative cooler made of paper/plastic film. In the area of pool boiling and condensing, the bubble jet loop heat pipe was studied. In the area of industrial heat exchangers, researches were performed on fin-tube heat exchanger, KSTAR PFC and vacuum vessel at baking phase, the performance of small-sized dehumidification rotor, design of gas-injection port of an asymmetric scroll compressor, effect of slot discharge-angle change on exhaust efficiency of range hood system with air curtain. (3) In the field of refrigeration, various studies were carried in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, a cold-climate heat pump system, $CO_2$ cascade systems, ejector cycles and a PCM-based continuous heating system were investigated. In the alternative refrigeration/energy system category, a polymer adsorption heat pump, an alcohol absorption heat pump and a desiccant-based hybrid refrigeration system were investigated. In the system control category, turbo-refrigerator capacity controls and an absorption chiller fault diagnostics were investigated. (4) In building mechanical system research fields, eighteen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the user and location awareness technology applied dimming lighting control system, the lighting performance evaluation for light-shelves, the improvement evaluation of air quality through analysis of ventilation efficiency and the evaluation of airtightness of sliding and LS window systems. The subjects of building energy were worked on the energy saving estimation of existing buildings, the developing model to predict heating energy usage in domestic city area and the performance evaluation of cooling applied with economizer control. The studies were also performed related to the experimental measurement of weight variation and thermal conductivity in polyurethane foam, the development of flame spread prevention system for sandwich panels, the utilization of heat from waste-incineration facility in large-scale horticultural facilities.

• Korean Journal of Veterinary Research
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• v.38 no.4
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• pp.756-762
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• 1998

The purpose of this study was to investigate the confirmation and prevalence of porcine cytomegalovirus (PCMV) infection of pigs in Korea using enzyme-linked immunosorbent assay (ELISA). Four hundred-eighty one sera tested were collected from the areas of Kyonggi, Kangwon, Chungcheong, Cholla, Gyongsang and Cheju during the year of 1991 to 1997 except 1994. PCMV antigen, OF-1 strain, for ELISA, was prepared 19-PFT-F cell line originated from porcine fallopian tube. Positive control was used by sera made from the specific pathogen free piglets which were infected with OF-1 strain. Three hundred-sixty seven of 481 sera (76.3%) were positive against PCMV. Antibody titers of these seropositives were classified by 129 (26.8%) cases in more than 1 : 12,800, 77 (16.0%) in 1 : 6,400, 76 (15.8%) in 1 : 3,200, 44 (9.2%) in 1 : 1,600, and 41 (8.5%) in 1 : 800, respectively. Also, the seropositive pigs were divided by 87.4% (76/87) in older than 6 month-old, 73.9% (238/322) in 2~6-month old, and 73.6% (53/72) in less than 2-month old, respectively. Regional prevalence rate of PCMV infection in Korea showed 89.7% (70/78) in Chungchong, 79.8/% (83/104) in Cholla, 79.4% (143/180) in Kyonggi, 79.3% (42/53) in Gyongsang, 50% (15/30) in Kangwon, and 38.9% (14/36) in Cheju area, respectively. In the sera collected in 1991, seropositive rate was appeared as 90.2% (37/41). From 1992 to 1997 except 1994, the average infection rate to PCMV was 77.5%. Consequently, these results confirmed that PCMV in Korean piggeries was introduced at least before the year of 1991. More importantly, PCMV infection has been prevailing nation-wide in pig herds in Korea.

• Journal of Energy Engineering
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• v.20 no.1
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• pp.36-43
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• 2011

Plant biomass has been proposed as an alternative source of petroleum-based chemical compounds. Especially, aromatic chemical compounds can be obtained from lignin by depolymerization processes because the lignin consist of complex aromatic materials. In this study, kraft lignin, the largest emitted substance among several kinds of lignin in Korea, was used as a starting material and was characterized by solid-state $^{13}C$-Muclear Magnetic Resonance($^{13}C$-NMR), Fourier Transform Infrared Spectroscopy(FT-IR), Elemental Analysis(EA). The depolymerization of kraft lignin was studied at water-phenol mixture solvent in near critical region and the experiments were conducted using a batch type reactor. The effects of water-to-phenol ratio and reaction temperature($300-400^{\circ}C$) were investigated to determine the optimum operating conditions. Additionally, the effects of formic acid as a hydrogen-donor solvent instead of $H_2$ gas were examined. The chemical species and quantities in the liquid products were analyzed using gas chromatography-mass spectroscopy(GC-MS), and solid residues(char) were analyzed using FT-IR. GC-MS analysis confirmed that the aromatic chemicals such as anisole, o-cresol(2-methylphenol), p-cresol(4-methylphenol), 2-ethylphenol, 4-ethylphenol, dibenzofuran, 3-methyl cabazole and xanthene were produced when phenol was added in the water as a co-solvent.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.5
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• pp.385-391
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• 2011

Purpose: The periosteum is a well-known source of osteogenic precursor cells for tissue-engineered bone formation. However, cultured endothelial or endothelial-like cells derived from periosteum have not yet been investigated. This study focused on endothelial-like cell culture from the periosteum. Methods: Periosteal tissues were harvested from the mandible during surgical extraction of lower impacted third molars. The tissues were treated with 0.075% type I collagenase in phosphate-buffered saline (PBS) for 1 hr at $37^{\circ}C$ to release cellular fractions. The collagenase was inactivated with an equal volume of DMEM/10% fetal bovine serum (FBS) and the infranatant was centrifuged for 10 min at 2,400 rpm. The cellular pellet was filtered through a $100{\mu}m$ nylon cell strainer, and the filtered cells were centrifuged for 10 min at 2,400 rpm. The resuspended cells were plated into T25 flasks and cultured in endothelial cell basal medium (EBM)-2. Results: Among the hematopoietic markers, CD146 was more highly expressed than CD31 and CD34. The periosteal-derived cells also expressed CD90 and CD166, mesenchymal stem cell markers. Considering that the expression of CD146 was constant and that the expression of CD90 was lower at passage 5, respectively, the CD146 positive cells in passage 5 were isolated using the magnetic cell sorting (MACS) system. These CD146 sorted, periosteal-derived cells formed tube-like structures on Matrigel. The uptake of acetylated, low-density lipoprotein, labeled with 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI-Ac-LDL) was also examined in these cells. Conclusion: These results suggest that the CD146-sorted positive cells can be referred to as periosteal-derived CD146 positive endothelial-like cells. In particular, when a co-culture system with endothelial and osteoblastic cells in a three-dimensional scaffold is used, the use of periosteum as a single cell source would be strongly beneficial for bone tissue engineering.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.1
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• pp.31-38
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• 2003

In the current electronic technology atmosphere, MEMS (Microelectromechanical System) technology is regarded as one of promising device manufacturing technologies to realize market-demanding device properties. In the packaging of MEMS devices, the packaged structure must maintain hermeticity to protect the devices from a hostile atmosphere during their operations. For such MEMS device vacuum packaging, we introduce the LTCC (Low temperature Cofired Ceramic) packaging technology, in which embedded passive components such as resistors, capacitors and inductors can be realized inside the package. The technology has also the advantages of the shortened length of inner and surface traces, reduced signal delay time due to the multilayer structure and cost reduction by more simplified packaging processes owing to the realization of embedded passives which in turn enhances the electrical performance and increases the reliability of the packages. In this paper, the leakage rate of the LTCC package having several interfaces was measured and the possibility of LTCC technology application to MEMS devices vacuum packaging was investigated and it was verified that improved hermetic sealing can be achieved for various model structures having different types of interfaces (leak rate: stacked via; $4.1{\pm}1.11{\times}10^{-12}$/ Torrl/sec, LTCC/AgPd/solder/Cu-tube; $3.4{\pm}0.33{\times}10^{-12}$/ Torrl/sec). In real application of the LTCC technology, the technology can be successfully applied to the vacuum packaging of the Infrared Sensor Array and the images of light-up lamp through the sensor way in LTCC package structure was presented.

• Applied Chemistry for Engineering
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• v.7 no.2
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• pp.379-386
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• 1996

Photosensitive compound, 1-methyl-4-[2-(4-diethylacetylphenyl)ethenyl] pridinium methosulfate(SbQ-A salt), was synthesized from dimethyl sulfate, terephthalaldehyde mono-(diethylacetal) and 4-picoline. SbQ-A salts were reacted with poly(vinyl alcohol)s, (PVA) in aqueous solution with phosphoric acid as catalyst to give photosensitive PVA-SbQ with different SbQ content and molecular weight. Relative photosensitivity of PVA-SbQ was determined by gray scale(GS) method. The rotative sensitivity of PVA-SbQ increased with increasing amount of bound SbQ in the case of high molecular weight(MW=77,000-79,000g/mol) as substrate and decreased with decreasing molecular weight of PVA with about constant(1.3mol%) amount of bound SbQ. The most sensitive polymer was obtained when SbQ group content in PVA-SbQ reached about 2.63mol% in the case of high molecular weight(77,000-79,000g/mol) PVA. This sample showed 90 times greater sensitivity than dichromated PVA as reference photosensitive system. PVA-SbQ photosensitive polymer synthesized was applied to the photolithographic screening process of phosphor on the panel of cathode ray tube(CRT). Phosphor slurry was made with PVA-SbQ, phosphor, a small amount of surfactant and other additives using water as medium. The slurry was coated onto panel, dried by heater, exposed to UV light and then developed by distilled water. When a small amount of cationic surfactant such as cetyltrimethylammonium chloride was used in the slurry formulation, the sharpness of phosphor pattern was equal to or better than that of dichromated PVA photosensitive polymer system used currently.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.1
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• pp.64-80
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• 1998

The risk of cross-contamination in dental clinic is very high. Those who are engaged in dental clinic are exposed to various microorganisms in saliva and blood of patient. Potential possibility of cross-contamination of patient to patient, patient to dentist, dentist to laboratory technician always exist, which is important in the view of public health. It is well known that microorganisms may cause cross-contamination by suck-back of microorganisms into the water supply line or air supply line of dental unit and sprayed back into the next patient's oral cavity. The majority of microorganisms coming from dental unit are water microorganisms from the main water supply which have colonized the tube within the units and multiplied in the relatively warm and stagnant conditions. The purpose of this study is to measure the extent of microbial contamination of dental unit and ultrasonic scaler, to evaluate that dental unit water supply is suitable for drinking water, and to assess the effect of flushing on reduction of microbial contamination of dental unit and ultrasonic scaler. In the first experiment, water samples(50ml) from 20 dental units and 10 ultrasonic scalers in Seoul National Univ. Hosp. were tested for the presence of coliform. The samples were filtered by membrane filtration technique.(Microfil system, Millipore Co. U. S. A.) The filter was then placed onto MacConkey agar plate and the plates with filter on it were incubated aerobically at $37^{\circ}C$ for 5 days. The colors and shapes of colonies were examined if those were coliform. To verify the presence of coliform, the colonies were inoculated into phenol red lactose broth and incubated aerobically at $37^{\circ}C$ for 2 days. The fomation of gas was observed. In the second experiment, water samples from 20 handpieces, 10 ultrasonic scalers and 30 A/W syringes after 0, 2, 4, 6 min. flushing respectively were taken. $200{\mu}l$ water samples were spreaded on Brain Heart Infusion agar plate and the plates were incubated aerobically at $37^{\circ}C$ for 5 days. The number of colony was counted. The results obtained were summarized as follows 1. The water from dental unit and ultrasonic scaler was not suitable for drinking water. 2. No coliform was founded in dental unit and ultrasonic scaler water supply. 3. The number of colony of dental unit and ultrasonic scaler was highest in the group of o min. flushing(p<0.05). 4. There was no statistically significant difference in the extent of microbial contamination among handpiece, ultrasonic scaler and A/W syringe (p>0.05). 5. The number of colony was lowest in the group of 4 min. flushing, but there was no statistically significant difference among 2, 4, 6 min. flushing groups.(p>0.05) 6. It is recommended to flush dental unit water line for 4 min. after use on each patient.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.4
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• pp.295-309
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• 2006

The present study was aimed to evaluate the incidence, etiological factors, and management of cleft lip and palate. Two hundred and twenty patients with cleft lip and/or cleft palate who were treated at Department of Oral and Maxillofacial Surgery, Chonnam National University Hospital, during the period between January 1994 and December 2003 were reviewed. The ratios of cleft lip : cleft lip with cleft palate : and cleft palate were 0.4:1.1:1. Males were more common than females in cleft lip (1.3:1) and cleft lip and palate (2.5:1), while females were more common than males in cleft palate (1:1.3). In the cleft side, left clefts were more prevalent than right clefts (cleft lip 1.3:1, cleft lip and palate 1.6:1). Unilateral clefts were more common than bilateral clefts in cleft lip (79:21). Cleft lip and cleft palate were more common in those with blood type A (34.5%) than those with other types. There was no significant relationship between birth season and frequency of clefts. The clefts were common in the first-born (48.8%), and in mothers aged between 25 and 29 (51.7%). Medication (24.7%) and stress (16.7%) during the first trimester were noted. Positive familial history was noted in 13 cases (5.9%). Thirty-two cases (15%) were associated with other congenital anomalies, in which tonguetie (40.6%) and congenital heart disease (21.9%) were most common. Among 100 patients with cleft palate, 77 patients had middle ear disease (77%), which occurred predominently in the incomplete cleft palate. Seventy-six among the 77 patients received myringotomy and ventilation tube insertion, and the remaining one received antibiotic medication only. Cleft lips were treated primarily at 3 to 6 months, and cleft palates were at 1 to 2 years. Treatment regimens included modified Millard method mainly in the cleft lip, and Wardill V-Y, Dorrance method, and Furlow method in the cleft palate. The percentage of palatal lengthening as type of cleft palate was greater in the incomplete cleft palate group (11.2%) than in the complete cleft palate group (9.6%). The percentage of palatal lengthening as operating method was no difference between the Furlow method (10.9%) and the push back method (10.7%). As postoperative complications, hypertrophic scar was most frequent in the cleft lip, and oronasal fistula in the cleft palate. In summary, it was shown that medication and stress during the first trimester of pregnancy were frequently associated with cleft lip and cleft palate, adequate timing and selection of method of operation are important factors to obtain morphologically and functionally good results. Furthermore prevention and treatment of middle ear disease are important in cleft palate patients because of its high co-occurrence.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.8
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• pp.1348-1352
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• 2004

More than 200 Bifidobacterium sp. originated from human intestine were investigated for their ability to produce conjugated linoleic acid (CLA). Of the Bifidobacteria tested, 1 of culture type strain and 12 isolated strains from Korean infants showed CLA producing ability. cis-9, trans-11 octadecadienoic acid presented more than 90% of the total CLA isomers produced by the Bifidobacteria. CLA content in fermented milk by Bifidobacterium sp. KHU 141 increased by 39.6 mg/l00 g, which showed the potential use for producing fermented milk containing high content of CLA. In fermented milk, little changes showed in lauric acid, myristric acid, palmitic acid, oleic acid, and linolenic acid contents, whereas the content of linoleic acid (LA) decreased and the content of CLA increased. Bifidobacterium sp. KHU 141 converted 86.0% and 84.8% of LA consumed to CLA for 24 hr and 48 hr fermentation, respectively. Prolonging incubation from 24 to 48 hours did not appear to enhance CLA formation and CLA producing ability was stable whether bottle, test tube, or fermenter was used for making fermented milk by Bifidobacterium sp. KHU 141.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7121-7126
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• 2013

Aim: To examine lymph nodes obtained after lipolysis and liposuction of subcutaneous fat of the inguinal region of female vulvar cancer patients to explore the feasibility of clinical application. Methods: The field of operation was on the basis of the range of the conventional resection of inguinal lymph nodes. We injected lipolysis liquid fanwise, started liposuction after 15-20 minutes; then the subcutaneous fatty tissue was sucked out clearly by suction tube. We selected the first puncture holes located on 2-3 cm part below anterior superior spine, the others respectively being located 3cm and 6cm below the first for puncturing into the skin, imbedding a trocar to intorduce $CO_2$ gas and the specular body, and excise the lymph nodes by ultrasonic scalpel. The surgical field chamber was set with negative pressure drainage and was pressured with a soft saline bag after surgery. Results: A lacuna emerged from subcutaneous of the inguinal region after lipolysis and liposuction, with a wide fascia easily exposed at the bottom where lymph nodes could be readily excised. The number of lymph nodes of ten patients excised within the inguinal region on each side was 4-18. The excised average number of lymph nodes was 11 when we had mature technology. Conclusion: Most of adipose tissue was removed after lipolysis and liposuction of subcutaneous tissue of inguinal region, so that the included lymph nodes were exposed and easy to excise by endoscope. This surgery avoided the large incision of regular surgery of inguinal region, the results indicating that this approach is feasible and safe for used as an alternative technology.