중공사 MD 모듈은 DCMD(Direct Contact Membrane Distillation) 방식으로 운전하는 경우 효율저하가 발생하는 이유로 주로 VMD(Vacuum Membrane Distillation) 방식으로 운전되었다. DCMD의 경우 고장을 줄일 수 있으며, 진공 펌프와 TVC 등을 필요로 하지 않아 경제적으로 열효율을 높일 수 있다면 선호되는 방식이다. 열효율을 향상시키기 위한 기초적인 방법으로 멀티모듈의 다양한 배열을 고려하기 위한 모듈 분석을 선행하였다. 이전연구를 통해 개발한 중공사막을 이용하여 모듈을 CFD 분석을 하여 운전방식(내외압, 병류 및 향류)에 따라 온도 및 유량조건별로 분석하였다. 이후 최적 운전방식을 기반으로 열교환효율에 적합한 모듈 배치를 모의하였다. 본 연구는 국토교통부 플랜트연구개발사업의 연구비지원(과제번호 18IFIPC146666-01)에 의해 수행되었습니다.

The impact of sodium hydroxide, which is one of chemicals of clean in place (CIP) for removing membrane fouling, on the PVDF membrane is reviewed with respect to physical/chemical structural change, the permeability affected therefrom. Based on the cleaning concentration applied in membrane water treatment facilities, 10% of accumulated defluorination was confirmed up to 166g.hr/L which reflects the exposure time. However, membrane resistance was confirmed to be reduced by about 10%. Through FT-IR and EDS analysis, reduction of F and change of are confirmed as factors that affect the permeability of membrane. Membrane resistance, which affects permeability, is affected by loss of additives for hydrophilicity, rather than defluorination of PVDF material. Therefore, in order to check membrane degradation degree, an accelerated test by NaOH was carried out, loss of additives was confirmed, and then PVDF inherent characteristic was observed.

농가에서 천적인 콜레마니진디벌을 처음 사용을 시도할 때, 작물재배지에 정착시키기 위해서 몇가지 변수에의해 성공여부가 결정되기도 한다. 이에 우리는 천적을 보다 안정적으로 활용하기 위한 조건들을 탐색하여 보고,그 중 실제로 사용하여 성공하였던 사례를 보고한다. 보다 성공적으로 진딧물 방제 결과를 얻기 위해서는 콜레마니진디벌 방사시 뱅크플랜트의 사용이 요구된다. 작물재배와 동시에 뱅크플랜트가 투입될 경우, 뱅크플랜트에 유인 진딧물류의 정착과 콜레마니진디벌이 안정적으로 정착되었는지 확인하는 절차가 요구된다. 지속적인 콜레마니진디벌 방사시기를 결정하고, 배송천적의 품질관리을 위하여, 간이적으로 콜레마니진디벌의 밀도를 간이적으로 평가할 수 있도록,작은 용기와 끈끈이트랩을 이용하는 방법을 제시하였다. 또한, 농가에서 천적을 배송 받은 후 바로 방사할 여건이어려울 경우, 배송된 콜레마니진디벌이 담긴 병 안에 꿀물을 급여하여 우화하기 시작한 기생봉의 생존율을 높일수 있도록 하였다.

포식성노린재는 최근 시설재배지에서 활용가치가 높이 평가되기 시작하고 있다. 이에 우리는 포식성노린재중담배장님노린재를 포장에 정착시키기 위한 방법을 모색하였다. 포식성노린재류의 먹이인 가루이류, 진딧물류 등의해충이 발생하지 않은 포장에 방사할 경우, 담배장님노린재는 먹이가 없어 방사한 포장에 정착하지 못하고 외부로날아가 비용대비 효과를 얻기 어려운 경우가 발생할 수 있다. 이에 우리는 국내에서 유통되고 있는 담배장님노린재를해충이 발생하지 않는 포장에 조기정착시키기 위한 방법으로, 유인식물로 알려진 참깨를 활용하여 담배장님노린재를정착시키고자 하였다. 또한, 농가에서 참깨 등 유인식물을 미리 준비하지 못한 경우를 대비하여 대체먹이를 선발하고자하였다. Ephestia kuehniella, Artemia franciscana, Typha angustifolia 등을 먹이로 제공한 결과, 담배장님노린재 약충발육기간은 각각 12.8, 13.5, 17.5일이었다.

천적 사용을 희망하는 농업인은 대부분 천적만으로 해충밀도가 조절되기를 기대한다. 그러나, 해충의 밀도조절을실패할 경우, 해충방제제를 선택도 고려되어야 한다. 이에 우리는 천적으로 활용 가능한 담배장님노린재와 미끌애꽃노린재에 대하여 타워스프레이를 이용하여 현미식초 등 10종의 유기농업자재별 독성평가를 실시하였다. 직접독성평가결과, 두 곤충 모두 제충국과 데리스에서 100%의 살충율을 보였다. 니코틴 처리구에서는 담배장님노린재는 85.7%의생존율을 보였고, 미끌애꽃노린재는 무처리구와 차이가 없었다. 흰가루병방제제로 활용되는 황토유황 1,000배 처리구에서 담배장님노린재는 71.4%, 미끌애꽃노린재는 66.7%의 생존율을 보였다.

곤충병원성 곰팡이 Zoophthora radicans (Entomophthorales: Entomophthoraceae)가 혹명나방, 배추좀나방, 복숭아혹진딧물과 진딧물 인 미분류 1종을 감염시키는 것을 발견하였다. 이들은 전라북도 진안, 김제, 익산에서 수집되었고, 6월과 9월에 관찰이 가능하였다. 이 균에 감염 된 혹명나방은 진안에서 수집되었고, 감염율이 46%에 달하였다. 감염된 곤충 충체로부터 균을 분리하여 Sabouraud dextrose agar with yeast extract (SDAY)를 이용하여 인공배양을 시도하였다. 그 결과, 20~28°C가 인공배양을 위한 최적온도로 판단되며, SDAY보다 SDAY supplemented with egg yolk and milk (SDAY-EM)에서 발육이 보다 양호하였다. 이 곰팡이는 자연적으로 발생함을 포장에서 확인할 수 있었다.

Various studies have forwarded an outstanding wastewater effluent treatment systems toward securing sustainable supply of water sources. In this paper, a broad overview of the performance of MF membrane as pretreatment option for wastewater reuse will be presented based on the literature survey and experiments conducted over the wastewater reuse pilot plant. The pilot plant was operated with a continuous data acquisition for about 300days under various chemical enhanced backwash (CEB) system with subsequent treated water quality analysis. Accordingly, assessment of the effluent revealed that the pretreated water is suitable enough to be used as an input for Reverse Osmosis (RO) unit and significant effect of CEB and concentration of NaOCl is also conceived from the analysis. Moreover, it's also observed that the application of various CEB condition over long operational hours induced a constant declination of overall performance of MF membrane.

The effects of dissolved inorganic and organic matter in seawater and the characteristics of fouling on the membrane surface were investigated within membrane distillation (MD) process. The changes of the membrane flux of PE and PVDF hollow fiber membranes under natural and synthetic seawater were compared with given variances of temperature. The flux of both membranes under the synthetic seawater, without any organic matter, were higher than that of the natural seawater, indicating the organic fouling on the membrane surface. The surface of the membrane was analyzed using scanning electron microscope (SEM) to examine the fouling. The experiment with organics has shown the formation of thin film over the membrane surface, while the experiment with inorganics has shown only the formation of inorganic crystals. The results indicated the organic matter as the major foulants and that the organics affected the formation of the crystals. Permeate water conductivity of all conditions verified the quality of the water to be better if not similar to that of RO.

In the present work, physicochemical treatments were introduced for de-aggregation and stable dispersion of detonation nanodiamonds (DND) in polar solvents. The DNDs in water exhibited a particle size of 138 nm and high dispersion stability without particular treatment. However, the DNDs in ethanol were severely aggregated to several micrometers in size and showed poor dispersion stability with time. To break down aggregates of DNDs and enhance the dispersion stability of them in ethanol, mechanical force and chemical surfactant were introduced as functions of zirconia ball size, kind of surfactant and amount of surfactant added. From the analyses of average particle size and Turbiscan results, it was suggested that the size of DNDs in ethanol can be reduced by only mechanical force; however, the DNDs were re-aggregated due to high surface activity. The long-term dispersion stability can be achieved by applying mechanical force to break down the aggregates of DNDs and by preventing re-aggregation of them using proper surfactant.

The present work investigated the dispersion behavior of Y2O3 particles into AISI 316L SS manufactured using laser cladding technology. The starting particles were produced by high energy ball milling in 10 min for pre- alloying, which has a trapping effect and homogeneous dispersion of Y2O3 particles, followed by laser cladding using CO2 laser source. The phase and crystal structures of the cladded alloys were examined by XRD, and the cross section was characterized using SEM. The detailed microstructure was also studied through FE-TEM. The results clearly indi- cated that as the amount of Y2O3 increased, micro-sized defects consisted of coarse Y2O3 were increased. It was also revealed that homogeneously distributed spherical precipitates were amorphous silicon oxides containing yttrium. This study represents much to a new technology for the manufacture and maintenance of ODS alloys.

In the present work, 6061 Al-B4C sintered composites containing different B4C contents were fabricated and their characteristic were investigated as a function of sintering temperature. For this, composite powders and their compacts with B4C various contents from 0 to 40 wt.% were fabricated using a planetary ball milling equipment and cold isostatic pressing, respectively, and then they were sintered in the temperature ranges of 580 to 660o C. Above sin- tering temperature of 640o C, real density was decreased due to the occurrence of sweat phenomena. In addition, it was realized that sinterability of 6061Al-B4C composite material was lowered with increasing B4C content, resulting in the decrease in its real density and at the same time in the increment of porosity.

Clay dispersion has been applied in Korean coasts since 1996 to minimize fisheries impact by Cochlodinium polykrikoides blooms. Understanding of spreading and sedimentation pattern of yellow clay in the sea after dispersion would be helpful for the counter measure of possible impact on marine environment and ecosystem by the clay. Tidal current movement and sedimentation of clay targeted on Obido island, Tongyong, Korea where clay had been frequently introduced to control red tide was calculated based on numerical model. The tidal current in the Obido channel showed northwestward flow during flood tide and southeastward flow during ebb tide with the highest water velocity of 15 cm/s, particularly, in the west mouth of the channel. Overall, the velocity of residual current in Obido channel with the highest value of 10 cm/s was higher than that between Obido and Mireukdo showing 1~3 cm/s of velocity with westward flow. Spreading and sedimentation of clay by the application of numerical model in the Obido channel was calculated under the assumption that 360 tons of clay had been introduced every day for 20 days in the area during red tide period in 2003. Clay particle spreaded toward westward in the channel and subsequently northward in the outside of the channel from the release point located in the center of the channel. It was calculated that 1.5 km2 in total nearby Obido area could be affected by the clay water with more than 1 mg/L of clay concentration within five tidal cycle after dispersion. The majority of the clay particle could be settled within 100 m from the release point with the sedimentation height of 10 mm. Also, it was calculated that the clay could show 0.2 mm of sedimentation height in the west and east mouth of Obido channel.

사이버 명예훼손은 현실상의 명예훼손이 사이버 공간에서 이루어지는 행위다. 사이버 명예훼손행위는 인터넷에 의하여 구현된 사이버 공간의 특성으로 인하여 피해가 커지고 있다. 명예훼손에 대한 피해의 규율은 ｢헌법｣, ｢민법｣, ｢형법｣ 및 특별법 영역에서 다루어졌다. 하지만 사이버 명예훼손의 피해에 대하여 기존 규제법과 책임법으로 규율되기엔 피해자가 겪는 고통이 크고, 가해자의 고의적인 악성이 정도를 넘었을 경우가 문제가 된다. 이러한 명예훼손 행위에 대하여 위자료청구권을 통한 높은 손해배상액을 청구한 사례와 징벌적 손해배상제도를 도입하자는 주장이 있어 왔다. 특히 명예훼손에 대한 징벌적 손해배상책임제도의 도입은 언론의 신중한 보도와 고의 및 과실에 의한 오보로 인한 피해의 구제 및 방지를 위하여 적용 판단을 할 필요성이 있다. 현재 징벌적 손해배상 도입 논의는 긍정설과 부정설이 대립해 있다. 따라서 사이버 명예훼손 행위에 대한 징벌적 손해배상제도의 도입 가능성에 대한 논의의 필요성이 있다. 사이버 명예훼손으로 인한 정신적 손해는 위자료청구권의 효과로서 금전 배상이 인정되지만 법관의 자유재량으로서 위자료 산정이 되기 때문에 패소자가 쉽게 납득할 수 없다. 그래서 이러한 단점을 보완하기 위하여 징벌적 손해배상제도의 도입이 필요하다. 사이버 명예훼손에 대한 징벌적 손해배상의 도입은 부정설의 논거를 충분히 판단하여 청구 영역을 특성화한 특별법의 형식으로 입법하는 방안이 타당할 것이다. 그래서 사이버 명예훼손 행위에 대한 징벌적 손해배상책임을 적용하는 경우를 명백히 하고, 책임의 범위를 합리적인 수준으로 제한한다면 언론 활동을 충분히 보장하면서도 명예훼손 피해자 보호 수준을 한 차원 높일 수 있을 것이다.

In this study, voltammetry system for realizing high sensitivity nano-labeled sensor of detecting heavy metals was designed, and optimal system operating conditions were determined. High precision digital to analog converter (DAC) circuit was designed to control applied unit voltage at working electrode and analog to digital converter (ADC) circuit was designed to measure the current range of at counter electrode. Main control unit (MCU) circuit for controlling voltammetry system with 150 MHz clock speed, main memory circuit for the mathematical operation processing of the measured current value and independent power circuit for analog/digital circuit parts to reduce various noise were designed. From result of voltammetry system operation, oxidation current peaks which are proportional to the concentrations of Zn, Cd and Pb ions were found at each oxidation potential with high precision.

In the present work, Al- composite powders were fabricated using a mechanical milling process and its milling behaviors and mechanical properties as functions of sizes ( , 500 nm and 50 nm) and concentrations (1, 3 and 10 wt.%) were investigated. For achieving it, composite powders and their compacts were fabricated using a planetary ball mill machine and magnetic pulse compaction technology. Al- composite powders represent the most uniform dispersion at a milling speed of 200 rpm and a milling time of 240 minutes. Also, the smaller particles were presented, the more excellent compositing characteristics are exhibited. In particular, in the case of the 50 nm added compact, it showed the highest values of compaction density and hardness compared with the conditions of and 500 nm additions, leading to the enhancement its mechanical properties.

This study investigated refinement behaviors of TiC powders produced under different impact energy conditions using a mechanical milling process. The initial coarse TiC powders with an average diameter of 9.3 were milled for 5, 20, 60 and 120 mins through the conventional low energy mechanical milling (LEMM, 22G) and specially designed high energy mechanical milling (HEMM, 65G). TiC powders with angular shape became spherical one and their sizes decreased as the milling time increased, irrespective of milling energy. Based upon the FE-SEM and BET results of milled powders, it was found initial coarse TiC powders readily became much finer near 100 nm within 60 min under HEMM, while their sizes were over 200 nm under LEMM, despite the long milling time of up to 120 min. Particularly, ultra-fine TiC powders with an average diameter of 77 nm were fabricated within 60 min in the presence of toluene under HEMM.

Hydrophobic nanodiamond (ND) were dispersed in engine oil (Helix Oil, Shell co.) as an additives to improve tribology properties. In this study, nanodiamond prepared by an explosive method was used. Tribology properties of both pure Helix oil and engine oil containing ND additive were evaluated. The rotating disks were made of Gray Cast Iron (240 Hv) and SKD11 (710 Hv). Surface topographies of the disks' wear tracks and friction coefficient were compared. The results show that nanodiamond-dispersed lubricants are capable of reducing these metals' wear loss. The friction coefficient is strongly affected to the hardness of wear track.