In this study, a two-stage electrostatic precipitator (ESP) was developed using a novel automatic dry cleaning device to reduce the ultrafine particles in subway stations. Collection efficiency was evaluated with a pilot scale ESP (1.2m× 1.2m) and the scale of the test duct was half of the subway air handling unit. The maximum collection efficiency for 0.3 μm particles was 96.9%. In addition, we studied a method of automatic dry cleaning for maintenance of the ESP. The cleaning efficiency was analyzed according to the cleaning flow rate for each particle loading amount to achieve a recovery rate over 90%. In addition, we derived the equation to estimate the reduction in collection efficiency according to the particle loading amount. It was confirmed that the performance of the contaminated ESP was restored to the initial state by the automatic dry cleaning in this study and that the electrical energy consumption was 5 times lower compared to utilizing conventional water cleaning.

This study was conducted to examine the oocyte recovery efficiency through having an OPU session once and twice a week. Also, the oocyte recovery efficiency was examined by using OPU after two and three months of rest period. Six cows were used for oocytes collection and were randomly divided into two groups. In experiment 1, OPU sessions were conducted once and twice a week to collect oocytes. The collected oocytes between once and twice OPU groups were classified into four groups (grade 1, 2, 3 and 4) according to the quality of cumulus cells and ooplasm. Based on the result, the percentage of collected oocytes per aspirated follicle number was similar between once and twice OPU session groups (65.5 ± 1.9 and 68.7 ± 1.4 vs.). However, the percentage of grade 1 oocytes from the twice OPU session group was significantly high compared with that of the once a week OPU session group (25.3 ± 0.9 and 32.5 ± 1.2% vs. once and twice session group, respectively, p < 0.05). In experiment 2, the group with three months of rest period tended to have a high percentage of collected oocyte compared with the group with two months of rest period (64.6 and 70.9% vs. 2 and 3 months rest group, respectively, p = 0.62). The percentage of grade 4 in the group with three months of rest period was significantly low compared with the group with two months of rest period group (27.3 and 36.5% vs. two and three months rest group, respectively, p = 0.05). In conclusion, twice a week OPU session is suitable for collection of high quality oocytes by using OPU, and three months of rest period is needed for the recovery of oocyte quality of a donor cow.

In this study, the changes in collection efficiencies due to the time changes of activated carbons were ascertained, and in order to identify the magnitude of adsorption, the before-use and after-use iodine adsorption values were analyzed. In addition, as a result of examining the characteristics of continuous process and non-continuous process and as a result of investigating whether the emission standards would be maintained, the continuous process and printing facilities were seen as not being able to maintain the emission standards. Also were found, in the case of non-continuous process,–taking into consideration the special nature of the job –for 4Ø palletized charcoal, a collection efficiency near 50% was shown even after 96 hours. Also, when the inlet concentration was about 300ppm, it is thought that the emission standards would be maintained if the activated carbons are replaced within at least 96 hours in the case of 4Ø palletized charcoal and the use was deemed pointless in the case of carbon. The results of this study are expected to provide assistance in selecting replacement periods for activated carbons and in selecting absorbents at the project sites, and are expected to be of significant help in the selection of precipitators that can collect total hydrocarbons for compliance of the emission standards.

Particle collection efficiency and air cleaning capacity were tested for the two-stage electrostatic precipitator for use in indoor air cleaning systems. A wire-plate type ionizer was used as a particle charger and a dielectric film consisted of polypropylene (or polyethylene) coated metals and zigzagged metal electrodes was used as a particle collector in the electrostatic precipitator. Both particle collection efficiency and air cleaning capacity increased as increasing the applied voltage on the charger and the collector, and furthermore, as increasing the collector film width (i.e. collection area). Air cleaning capacities estimated by the product of particle collection efficiency and air flow rate were quite well consistent with the experimental ones with a proportional constant of 0.964. Ozone concentrations emitted from the charger at the applied voltages of 5.0 and 5.2 kV were less than 0.05 ppm, indoor ozone standards of UL 867-2002, KS C 9314 and SPS-KACA002-132. For the air flow rate of 11.7 m³/min, the applied floor area of 48.2 m² could be obtained when 5.2 kV and 6.0 kV were applied on the ionizer and the collector, respectively and the collector of two 15 mm polyethylene dielectric films was used.

도축장에서 회수한 한우 난소로부터 난자를 회수하기 위한 방법으로 흡입법 후 세절법과 흡입법으로 난자를 회수하여, 난자의 회수율과 채란된 난자를 체외수정 후 발달율과 수정란 이식 후 수태율에 영향을 조사한 결과는 다음과 같다. 1. 난자 회수율은 각 난소당 회수된 난자수는 흡입 후 세절법이 8.2개, 흡입법이 6.5개로서 흡입 후 세절법을 병용하는 것이 난자 회수율에서 유의적으로 많았다. 2. 채란방법에 따른 체외수정란의 분할율은 흡입 후 세절법이 , 흡

In order to develop combination air filters for air conditioners, 2 types of charging section were constructed. One was the wire-plate type and the other was the scroll type. Each charging section was combined with the same electrostatic polypropylene (PP) media. NaCl aerosol particles with geometric mean diameter of 0.05∼0.16㎛, geometric standard deviation of 1.6∼1.9 and total number concentration of 1,700∼24,000 particles/㎤ were used to determine collection efficiencies of the combination air filters for air conditioners with respect to particle size. It was shown that the scroll type combination air filter has greater collection efficiencies and lower pressure drops than the wire-plate type one does.

자연열(태양열)을 효율적으로 이용하기위해 1999년부터 2000년 까지 2년간 상면적이 100m2인 3동의 유리온실에 각기 다른 집열시스템을 설치하였다. 즉, 집열면적과 경사도가 각각 24m2, 50˚로서 현재 시판되고 있는 태양열 집열기(평판형, Solar hart Inc.)를 이용하는 방법, 직경과 송풍량이 각각 1m, 2.5m-3.m-2 .min로서 라디에이터가 부착된 2개의 유동팬을 천장부에 설치하고 천창을 밀폐한 후 온실상부의 열을 집열하는 방법, 온실의 중도리 전부를 물이 순환되는 각관 (75x45x3t, 1m 간격x10줄x온실길이 12m=120m)으로 설치하여 집열하는 방법 등으로 하였다. 각 동마다 지하에 26톤의 저수 능력을 갖는 D2000xW1500xL8600의 축열조를 설치한 후 중간을 막아 저온수조와 고온수조로 구분하였고, 수조 중간 1.5m 높이에 통수로를 내어 일정량의 물(약 15톤)이 지속적으로 순화될 수 있도록 하였다. 최저기온 9℃로 설정하여 1,000m2를 공간 난방할 경우 난방연료 절감율은 태양열 집열기, 유동팬 및 각관에서 각각 7%, 19%, 28%로 나타났다. 태양열 집열기를 이용하는 대부분의 농가에서는 40~50m2 정도의 집열면적을 갖는 집열기를 이용하고 있는데 이 경우 년간 난방연료 절감율은 14% 정도로서 경제성이 없으며, 유동팬도 집열효율에 비해 제작, 설치 및 유지비가 과다하게 소요되므로 경제성이 없다. 각관의 경우 관 자체의 자재비나 설치비에 추가부담이 적으면서 집열효율이 비교적 높기 때문에 관의 부식, 골조 표면적 증가에 의한 시설내 차광 증가, 중도리의 각형 구조로 인한 강도저하 등의 문제가 해결되면 집열 방법으로 고려될 수 있을 것이다.

본 실험은 솔잎혹파리의 성충우화수 조사기구를 개발하기 위하여 경기도 안양시 안양리 산 160번지와 수원시 서울대학교 농과대학에서 실시하여 다음과 같은 결과를 얻었다. 1. 솔잎혹파리의 우화기간은 5월 중순부터 8월중순이었고 우화최성기는 기구별로 차이가 있어 표준형은 5월 29일-6월 2일, Funnel-A형은 6월 3일-7일, Suction형 Trap은 6월 8일-12일간이었다. 2. 우화율은 실내실험구의 Funnel-A형에서 였다. 3. Suction형 Trap은 밀도가 낮은 우화초기와 말기에 보호효과가 현저히 우수하였다. 4. 기존 표준우화상의 결점을 보완하기 위해 Funnel-A형과 Suction형 trap의 개발이 바람직하다.

This study was carried out to investigate the collection Efficiency of mass in collector step at the different of physical gas characterization. This work has focused on the dependence of the collection efficiency of mass in the collector zone of a two-stage set up field with gas temperature T and the dew point tmeperature. To identify the dependence of the mass collection efficiency on the grounded plate of the collector zone M_P,k by the specific electric resistance of dust ρe and the relative humidity φ, 20 attempts have been made with three different gas temperature (50℃, 80℃, 110℃) at different dew point. At the specific electric resistance of dust ρe=10^6Ωm which relative humidity corresponds to φ> 15%, a easy rise of the grounded plate secluded dust mass share was measured again. As the result of the higher cohesion imprisonment power due to the adsorbtion of particle, the rise of the relative humidity developed on the particle surface. Therefore, the collection efficiency of mass was not predominant the high temperature T in the collector zone, neither was the pecific ellectric resistance of dust dependent.