• 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.

• Journal of Chest Surgery
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• v.29 no.9
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• pp.951-958
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• 1996

Bet een November 1991 and December 1993, twelve patients (Male: 2, Female: 10) who had mitral valve disease without primary pulmonary disease underwent mitral valve replacement. The pulmonary function test (PFT) was performed preoperatively and postoperatively (mean, 9 months after operation). Mitral valve replacement was indicated for mitral stenosis in 9 patients and for mitral insufficiency in 3 patients. Preoperative WHh functional class were 111 in 11 patients and class rV in 1 patient. Postoperatively, ten patients (83 %) were classified into NYHA functional class 1. There was a significant decrease in cardiothoracic ratio (CTR) postoperatively (p< 0.05). The pulmonary function before operation was low compared with predicted values in vital capacity (VC) and forced mid-expiratory flow (FEF 25∼75 %). The FEF 25%-75% and maximal voluntary ventilation (MW) were low compared with predicted values postoperatively. There was no significant difference in the pulmonary function before an after op- eration. Twelve patients were divided into 2 groups according to the early postoperative NYHA functional class. In class I group, the postoperative pulmonary function was significantly improved in 6 parameters (RV, FRC, TLC, FEVI , FEVI /FVC, and FEF 25∼75%), but in class ll group, there was no significant change in the pulmonary function after operation.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.10
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• pp.1417-1429
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• 2004

The objective of the paper was to study the drinking and other related behavior of dairy cows (Bos taurus). There were 142 Holstein dairy cows observed and compared in this study. The experiment was designed on the basis of two different housing systems (wet pad with forced ventilation cooling house and open house); two different seasons (winter and summer); four different stages (high milk yielding cows, low milk yielding cows, dry cows, and heifers); and grouping (home and visitor animals). All cows had free access to water. Dairy cows spent 13.8 min/day drinking in wet-pad house and 11.7 min/day in open house. owever, there was no significant difference in the duration of water drinking between these two housing systems (p>0.05). The water consumption was significantly higher in wet-pad housed animals (68 L/day) than open-housed animals (31.5 L/day) (p<0.05). A significant interaction between housing and grouping (p<0.05) was found. Home and visitor animals spent more time drinking in open house, wet-pad house, respectively. A highly significant interaction was found between housing and drinking time during the day (p<0.001). Animals in open house drank more during the morning (6:00 to 10:00 h), whereas wet-pad housed animals drank in the afternoon (14:00 to 15:00 h) and evening (18:00 to 20:00 h). The average time a cow spent in drinking in summer was not ignificantly different from that of drinking in winter. However, the water intake was significantly higher in summer (61.9 L/day) than in winter (38.6 L/day) (p<0.05). Drinking activity showed a highly significant interaction between season and physiological stage (p<0.01). High milk yield cows spent more time drinking in summer than in winter, whereas cows in all other stages followed the opposite drinking pattern. Grouping exchange did not influence the drinking behavior of dairy cows in either season (p>0.05); both home and visitor animals spent almost the same time in drinking water. A strong significant interaction between season and time during the day was found(p<0.01), suggesting that animal's high drinking frequency occurred during the daytime for both seasons, with a peak midday in winter and two peaks at 10:00 h in the morning and 19:00 h in summer. Thus, drinking behavior was associated with the cooler time of day in summer and with the warmer hours of day in winter. High and low milk yielding cows and heifers spent 15.3 min/day, 14.3 min/day, and 12.8 min/day, respectively, in water drinking activity, but there was no significant difference among them (p>0.05). There was, however, a significant difference in water drinking activity found in dry cows, which spent less time in drinking at 8.2 min/day (p<0.05).

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.7
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• pp.952-961
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• 2003

In the first part of the study, rates of estrus occurrence and success of A.I. service in the Thai-native and Friesian crossbred, and purebred Friesian cows fed in the National Dairy Training and Applied Research Institute in Chiang Mai, Thailand were traced monthly throughout a year. An electric fan and a water sprinkler cooled the stall for the purebred cows during the hot season (March-September). Both rates in pure Friesians were at their highest in the cold-dry season (October- February), but they decreased steadily during the hot-dry season (March-May) and were at their lowest in the hot-wet season (June-September). Seasonal change of a similar pattern was observed in the incidence of estrus, but not in the success rate of insemination in the crossbred cows. By the use of reproductive data, compiled in the same institute, on the 75 % cross- and purebred Friesian cows, and climatological data in Chiang Mai district, effects of ambient temperature and humidity on the reproductive traits of cows were examined by regression analysis in the second half of the study. Significant relationships in the crossbred, expressed by positive-linear and parabola regressions, were found between reproductive parameters such as days to the first estrus (DTFE), A.I. service (DTFAI), and conception, the number of A.I. services required for conception and some climatic factors. However, regarding this, no consistent or intelligible results were obtained in purebred cows, perhaps because electric fans and water sprinklers were used for this breed in the hot season. Among climatic factors examined, the minimum temperature (MINT) in early lactation affected reproductive activity most conspicuously. As the temperature during one or two months prior to the first estrus and A.I. service rose, DTFE and DTFAI steadily became longer, although, when MINT depleted below $17-18^{\circ}C$, the reproductive interval tended to be prolonged again on some occasions. The maximum temperature also affected DTFE and DTFAI, but only in limited conditions. The effect of humidity was not clear, although the inverse relationship between DTFE and minimum humidity during 2 months before the first estrus in the crossbred seemed to be significant. Failure to detect any definite effect of climate on the reproductive traits of pure Friesians seemed to indicate that forced ventilation by electric fans and water sprinklers were effective enough to protect the reproductive ability of this breed from the adverse effects of a hot climate.

• Journal of Adhesion and Interface
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• v.21 no.3
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• pp.81-85
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• 2020

Shaving dust is a collagen fiber that is the leather waste occurred for thickness adjustment during the natural leather manufacturing process, and causes problems such as an environmental contamination because of a chromium (Cr) contained when it comes to reclaiming process. Various studies applying the shaving dust are currently being conducted in many countries across the world with an initiative by the EU. Of those applications, the bonded leather is being highlighted as a substitute for natural leather. Since the bonded leather, however, uses latex as a binder, accordingly it entails a high weight and a poor ventilation, which are deemed as disadvantages due to its dense internal tissues compared to other synthetic leathers. To address such disadvantages, this study employed the thermally expandable micro sphere to improve its air permeability and light weight by alleviating the internal structure. This is a study on the manufacturing of light bonded leather using the shaving dusts. In the study, the shaving dusts were forced to foam under 100~120℃ considering the heat resistance of collagen fiber after applying the thermally expandable micro sphere, and then the tendency was analyzed. In the analysis results, the most excellent foaming rate was exhibited when the shaving dusts were treated under 120℃ for 8 minutes and the variation of internal structure according to a foaming was observed through SEM analysis for the cross-section of the bonded leather.

• Food Science and Preservation
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• v.15 no.4
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• pp.556-561
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• 2008

This study was carried out to identify the cause of benzo(a)pyrene[B(a)P] production during the manufacture of sesame oil and perilla oil, and to minimize such B(a)P synthesis. The distribution of B(a)P in sesame seed and perilla seed differed with seed-growing district, the range was $0.06{\sim}0.31{\mu}g/kg$ in domestic seed and $0.12{\sim}0.47{\mu}g/kg$ in imported seed. B(a)P contents after roasting at $220^{\circ}C$ for 20 min in sesame seed and perilla seed were $1.87{\sim}2.47{\mu}g/kg$ and $2.12{\sim}2.43{\mu}g/kg$, respectively, and levels in oils obtained from the roasted seeds were $3.68{\mu}g/kg$ and $4.64{\mu}g/kg$, respectively. These data refer to seeds subjected to codsed roasting. With open roasting, the levels were $0.63{\mu}g/kg$ and $0.56{\mu}g/kg$, respectively. Closed roasting resulted in absorption of B(a)P, with consequent high levels in oils. We introduced forced ventilation during closed roasting. We tested various methods to remove B(a)P from sesame oil and perilla oil. Neither centrifugation nor filtering with diatomite and diatomiteactive carbon removed B(a)P. A filtering method using active carbon was effective. But this method adversely affected the color and flavor of sesame oil and perilla oil.

• Journal of agriculture & life science
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• v.45 no.4
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• pp.135-141
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• 2011

This research was conducted to provide basic data of surplus heat for designing solar heat-storage systems. The surplus heat is defined as the heat exhausted by forced ventilations from the greenhouses to control the greenhouse temperature within setting limits. Various simulations were performed to compare the differences of thermal behaviors among greenhouse types as well as among several domestic areas by using pseudo-TMY (Typical Meteorological Year) data manipulated based both on the weather data supplied from Korean Meteorological Administration and the TMY data supplied from The Korean Solar Energy Society. Additional analyses were carried out to examine the required heating energy together with some others such as the energy balances in greenhouses to be considered. The results of those researches are summarized as follows. Regional surplus solar heats for the nine regions with 4-type were analyzed. The results showed that the ratio of surplus solar energy compared to heating energy was the highest in Jeju (about 212.0~228.0%) for each greenhouse type. And followed by Busan, Kwangju, Jinju, Daegu, Daejeon, Jeonju, Suwon and Daekwanryung. And irrespective of greenhouse types, surplus solar energy alone could cover up nearly all of the required supplemental heating energy except for a few areas.

• Journal of Life Science
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• v.20 no.3
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• pp.437-443
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• 2010

This study was designed to examine the aerobic capacity and ventilatory response during an incremental exercise in elite high school cyclists. Twelve boys ($17{\pm}1\;yr$, $175{\pm}5\;cm$, $70{\pm}9\;kg$) participated in anthropometric measurements, incremental exercise testing, and pulmonary function tests. During incremental exercise testing using a cycle ergometer, their maximal oxygen uptake ($VO_2max$), maximal power output, ventilation, ventilatory equivalents for oxygen ($V_E/VO_2$) and carbon dioxide ($V_E/VCO_2$), respiratory rate, and tidal volume were measured. Time variables such as inspiratory time (Ti), expiratory time (Te), breathing time (Tb), and inspiratory duty cycle (Ti/Tb), as well as inspiratory flow rate ($V_T$/Ti) were assessed. Pulmonary function of vital capacity (FVC), forced expiratory volume in one second ($FEV_1$), $FEV_1$/FVC, and peak expiratory flow were evaluated. Their $VO_2max$, maximal heart rate, and Wmax were $57.5{\pm}3.9\;ml{\cdot}kg^{-1}{\cdot}min^{-1}$, $194.1{\pm}8.6\;beat{\cdot}min^{-1}$, and 452 W, respectively. $VO_2max$ was not related to any anthropometric parameters. Most ventilatory variables progressively increased with exercise intensity. As intensity increased, Ti, Tb, Tb decreased while Ti/Tb was maintained. Below an intensity of 250 W, height, weight, body mass index, and body surface were highly correlated with $V_T$/Ti and Ti/Tb (p<0.05). Collectively, $VO_2max$ appeared to be lower than adult cyclists, suggesting a different pattern of ventilatory control as age advances. Morphological characteristics were not related to $VO_2max$ in the population. Time variables of ventilatory response seemed to be related only at an exercise intensity level of less than 250 W. $V_T$/Ti may be related to exercise endurance capacity, but Ti/Tb was similar to adult cyclists.

• Journal of Animal Science and Technology
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• v.48 no.4
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• pp.555-562
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• 2006

The objective of this study was to evaluate the effects of dietary cation-anion difference (DCAD) with or without ruminally protected fat and niacin on the thermoregulatory ability, milk yield and milk composition of lactating dairy cows during summer in Korea. Thirty mid-lactating Holstein cows (134±12.4 DIM and 23.4±2.3kg/d of milk yield) were divided into three groups (10 animals/group). Cows were housed in a free-stall barn and were provided with forced- air ventilation (wind velocity = 4 m/s) using 41 cm diameter fans. Diet one was formulated to contain low DCAD (+15 DCAD) while the remaining two diets were higher in DCAD (+30 DCAD). One higher DCAD diet was formulated to contain by-pass fat and the second higher DCAD diet contained the niacin along with by-pass fat. The maximum ambient temperature during July was 28.5℃ which could be seen as a period of mild heat stress. As summer progressed, August was characterized as a severe heat stress condition with maximum ambient temperature (32.4℃) and THI (74.0). Dry matter, crude protein and total digestible nutrients intake was not affected by the DCAD level and supplementation of ruminally protected fat or niacin. Milk production was higher in cows fed diets supplemented with fat and niacin than those fed un-supplemented diet. No difference in milk yield was observed in cows fed diets supplemented with fat or niacin plus fat. Milk fat and rectal temperature were not affected by the DCAD level and supplementation of ruminally protected fat or niacin. However, respiration rate was decreased in cows fed diets supplemented with either fat or fat and niacin compared to those fed. The results of the present study indicated that higher DCAD (+30) and supplementation of fat along with niacin can somehow mitigate the negative effects of heat stress on milk yield and physiology of lactating Holsteins during July and August in Korea. In present study reduced respiration rate and increased milk yield in lactating cows may be attributed to the cooling effect of supplemented fat along with vasodilatory functions of niacin. (Key Words: DCAD, Heat stress, THI, milk yield, Milk fat, Holstein)

• Tuberculosis and Respiratory Diseases
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• v.47 no.5
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• pp.609-617
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• 1999

Background: The aims of this study were to assess the etiologies, survival and prognostic factors of patients with chronic cor pulmonale visited Pusan National University Hospital. Methods : This study included 103 patients with chronic cor pulmonale. There were 67 men and 36 women. The diagnosis of chronic cor pulmonale was primarily based on the presence of underlying lung disorder and echocardiographic finding of enlarged or hypertrophied right ventricle. Other clinical data including patients' symptoms and signs, findings of arterial blood gas analysis, hematologic and biochemical laboratory and pulmonary function test were assessed. Results: The most common underlying lung disorder was pulmonary tuberculosis(59.2%) and chronic obstructive pulmonary disease was the next(28.2%). The survival rate was 57% in one year, 45% in two years, and 34% in three years. The prognostic factors were maximal voluntary ventilation(MVV), forced vital capaoity(FVC), $FEV_1$ serum Na, vital capacity(VC), serum albumin and peak expiratory flow(PEF) in univariate analysis. And in multivariate analysis, serum albumin(p=0.0144) and VC(p=0.0078) were statistically significant. Conclusion: Pulmonary tuberculosis was the most important underlying lung disorder in chronic cor pulmonale. The survival rate was 57% in one year, 45% in two years, and 34% in three years. Serum albumin (p=0.0144) and VC(p=0.0078) were statistically significant prognostic factors.