• Journal of Animal Environmental Science
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• v.8 no.2
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• pp.99-106
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• 2002

This study was conducted to improve utilization efficiency of slurry and choose a suitable type of tractor power which can be attached by manure spreader in the paddy field. In the paddy field, the pulling force for the spreader was measured by using a measurement system installed between tractors with and without the spreader. The soil moisture contents at the 0${\sim}$10cm and 10${\sim}$20cm depth of test soil(SiCL) were 28.45% d.b. and 23.47% d.b., respectively in average while Cone Index at l0cm and 15cm depth were 14.5kPa and 16.2kPa, respectively. It was impossible to measure the soil moisture contents and Cone Index below 20cm depth of the soil because the hardness of the soil increased greatly. Thereafter, hard pan of the sampled soil was found at 15${\sim}$20cm depth. While the required power only for the dragged tractor was found to be 3.44kW in the test field, the required pulling powers of tractor considering the pumping were 8.48${\sim}$12.48kW, 12.19${\sim}$16.19kW, 16.96${\sim}$20.96kW, respectively for 2 tons, 3 tons, and 4 tons of tank capacity. As the tank capacity increased, the sinkage of soil were also increased to 7cm, l0cm, and 12cm, respectively for the tractors with 2 tons, 3 tons and 4 tons of tank capacity. Considering about 60% of pulling efficiency of tractor, a tractor which had lower than 25.74kW of pulling power was suitable to pull the spreader and spread the slurry simultaneously for manure spreader with 2 tons of tank capacity. 29.42kW${\sim}$36.78kW of pulling power was found to be optimum for the tractor with 3 tons of tank capacity while over 40.45kW for 4 tons of tank capacity.

• Economic and Environmental Geology
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• v.35 no.1
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• pp.25-41
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• 2002

In order to investigate the hydrogeochemical characteristics and contamination of dissolved major ions and heavy metals in the Tancheon River, river water and sediment samples were collected at 18 locations, along a distance of 69 km, between Yongin-si in Kyunggi-do and Samsung-dong in Seoul on October in 2000 and April in 2001. After appropriate sample preparation, waters were analyzed for the dissolved constituents and sediments. The pH values of river waters were in the range of 7.0 to 9.3 and could be plotted in the area of surface environment. The level of $Ca^{2+}$, , CI-, sol-, N0$_{3}$ and HC0$_{3}$ in the Tancheon River were higher than those in world average river water. Most of dissolved constituents in the river waters increased toward downstream from upstream. In particular, high concentrations of Zn2+, Na$_{+}$, CI$^{-}$, SO$_{4}^{2-}$ and N03- were found near densely residential areas and the Sungnam waste water treatment plant. The relative ion enrichment was caused by the inflow of local domestic and industrial sewages. Also, Ca2+ and HC03- concentrations were enriched in the middle of the Tancheon River due to the dissolution of cements. This indicates that the apartment complexes were built on a large scale in the upriver since these ten years and large amounts of construction materials such as cements were flowed into the Tancheon River. Concentrations of heavy metals (Mn, Cd, Cu, Pb, Zn) in sediments from the Tancheon River exceeded the lower limit of tolerence level in bottom sediment established by the Ontario Ministry of the Environment (OME) of Canada. In particular, these metals were highly elevated in sediment (TSM-12) collected from near the Sungnam waste water treatment plant. Heavy metals were higher enriched in sediments collected from dry period rather than wet period.

• Journal of the Korean Chemical Society
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• v.44 no.3
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• pp.220-228
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• 2000

This study deals with the water qualities of Dalgi mineral spring in Cheongsong district.Water samples which were taken from upper, middle and bottorn spring sites were tested for twenty eight important water quality items including minerals, essential and/or toxic trace elements, and the analytical items to affect the taste of mineral water, seasonally from May 1999 to February 2000 The results obtained wereas follows:Each spring site showed much difference in major items. Bottom spring water showed higher value of Mg and Na than others. Middle spring water showed the highest value in all of the items except Mg and Na. The concentration of Hardness, Fe and Mn in mineral water were over than the normal standard for drinking water, but these items are not specified for the mineral water. As, Cd, $Cr^{6+}$ and Hg were not found and Pb was found ln trace level. All of the items proved nearly constant during the four seasons except water temperature. The contribution of mineral water to the nutrition of human was calculated in order to investigate the health effect of drinking water on the bases of Required Daily Allowance,one liter of water drinking and the mineral concentration of the bottom spring. The percentage of consumable minerals of Ca, Mg, Na, K, Mn,Zn and Fe were 35.05,36.43,5.88∼10.63,0.19∼0.57,21.86∼43.72,0.65, and 95.l respectively. This means Dalgl mineral water is pIenty of iron mineral. The K and O indexes of mineraI water appeared to be good for healthy and delicious water.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.5
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• pp.543-553
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• 2010

Almost five million citizens a day are using subways as a means of traffic communication in the Seoul metropolitan. As the subway system is typically a closed environment, indoor air pollution problems frequently occurs and passengers complain of mal-health impact. Especially $PM_{10}$ is well known as one of the major pollutants in subway indoor environments. The purpose of this study was to compare the indoor air quality in terms of $PM_{10}$ and to quantitatively compare its source contributions in a Seoul subway platform before and after installing platform screen doors (PSD). $PM_{10}$ samples were collected on the J station platform of Subway Line 7 in Seoul metropolitan area from Jun. 12, 2008 to Jan. 12, 2009. The samples collected on membrane filters using $PM_{10}$ mini-volume portable samplers were then analyzed for trace metals and soluble ions. A total of 18 chemical species (Ba, Mn, Cr, Cd, Si, Fe, Ni, Al, Cu, Pb, Ti, $Na^+$, $NH_4^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, and ${SO_4}^{2-}$) were analyzed by using an ICP-AES and an IC after performing proper pre-treatments of each sample filter. Based on the chemical information, positive matrix factorization (PMF) model was applied to identify the source of particulate matters. $PM_{10}$ for the station was characterized by three sources such as ferrous related source, soil and road dust related source, and fine secondary aerosol source. After installing PSD, the average $PM_{10}$ concentration was decreased by 20.5% during the study periods. Especially the contribution of the ferrous related source emitted during train service in a tunnel route was decreased from 59.1% to 43.8% since both platform and tunnel areas were completely blocked by screen doors. However, the contribution of the fine secondary aerosol source emitted from various outside combustion activities was increased from 14.8% to 29.9% presumably due to ill-managed ventilation system and confined platform space.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.6
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• pp.711-722
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• 2011

This study is aimed to estimate the $PM_{2.5}$ source apportionment at Seoul intensive monitoring site located in Seoul metropolitan area. Time-resolved chemical compositions of $PM_{2.5}$ are measured in real time using ambient ion monitor, semi-continuous carbon monitor, and on-line XRF at Seoul intensive monitoring site in 2010. The mass concentration of $PM_{2.5}$ was simultaneously monitored with eight ionic species (${SO_4}^{2-}$, $NO_3{^-}$, $Cl^-$, $NH_4{^+}$, $Na^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$), two carbonaceous species (OC and EC), and fourteen elements (Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Pb) in 1-hr interval. The data sets were then analyzed using EPA PMF version 3 to identify sources and contributions to $PM_{2.5}$ mass. EPA PMF modeling identified eight PM2.5 sources, including soil dust, secondary sulfate, secondary nitrate, motor vehicle, coal combustion, oil combustion, biomass burning, and municipal incineration. This study found that the average $PM_{2.5}$ mass was apportioned to anthropogenic sources such as motor vehicle, fuel combustion, and biomass burning (61%) and secondary aerosols, including sulfate and nitrate (38%).

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.81.2-81.2
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• 2012

To fabricate a metal mold for injection molding, hot-embossing and imprinting process, mechanical machining, electro discharge machining (EDM), electrochemical machining (ECM), laser process and wet etching ($FeCl_3$ process) have been widely used. However it is hard to get precise structure with these processes. Electrochemical etching has been also employed to fabricate a micro structure in metal mold. A through mask electrochemical micro machining (TMEMM) is one of the electrochemical etching processes which can obtain finely precise structure. In this process, many parameters such as current density, process time, temperature of electrolyte and distance between electrodes should be controlled. Therefore, it is difficult to predict the result because it has low reliability and reproducibility. To improve it, we investigated this process numerically and experimentally. To search the relation between processing parameters and the results, we used finite element simulation and the commercial finite element method (FEM) software ANSYS was used to analyze the electric field. In this study, it was supposed that the anodic dissolution process is predicted depending on the current density which is one of major parameters with finite element method. In experiment, we used stainless steel (SS304) substrate with various sized square and circular array patterns as an anode and copper (Cu) plate as a cathode. A mixture of $H_2SO_4$, $H_3PO_4$ and DIW was used as an electrolyte. After electrochemical etching process, we compared the results of experiment and simulation. As a result, we got the current distribution in the electrolyte and line profile of current density of the patterns from simulation. And etching profile and surface morphologies were characterized by 3D-profiler(${\mu}$-surf, Nanofocus, Germany) and FE-SEM(S-4800, Hitachi, Japan) measurement. From comparison of these data, it was confirmed that current distribution and line profile of the patterns from simulation are similar to surface morphology and etching profile of the sample from the process, respectively. Then we concluded that current density is more concentrated at the edge of pattern and the depth of etched area is proportional to current density.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.8
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• pp.386-396
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• 2006

We implemented the Drug-Pad Moxibustion Method in order to improve the conventional moxibustion therapy. This method is aimed to eliminate burning wounds and smoke, which are the defects of conventional moxibustion therapy. And we performed to verify the efficiency by comparing the Drug-Pad Moxibustion Method with the conventional Indirect Moxibustion Therapy. We measured the body heat and the lasting time of blood circulation improvement using thermography. The moxibustion therapy has two kinds of effects: The formers are pharmacological effects of the Moxa's vasodilators and antioxidants. The latters are thermal effects which cause improvement of the blood circulation. To remove the demerits without omission of above therapeutic effects, we extracted the vasodilators and antioxidant compounds from the Moxa-$CH_2Cl_2$ fraction Moxa-EtOAc and composed the moxibustion kit with $(Ba_{0.8}\;Sr_{0.2})_{0.996}\;Y_{0.004}\;TiO_2+0.5_{WT}\;SiO_2%$ Positive Temperature Coefficients Thermistor. The experimental demonstrations have been made by the stimulating the spot which is CV4(Kwan-Won), CV8(Shin-Guel), CV12(Jung-Wan) acupuncture points of the conception vessel meridian(CV). And stimulating time was one hour. We divided the subjects into 5 groups such as no stimulation group, conventional Indirect Moxibustion group, only Drug-Pad stimulation group, only heat stimulation group, and Drug-Pad Moxibustion group. In the different cases, we have measured the body heat in pre-stimulation, just after stimulation, 2 hours after, and 4 hours after. The body heats of the group who were stimulated by the Drug-Pad Moxibustion Method were increased by over the $2^{\circ}C$. And the body heats of the group who were stimulated by the Indirect Moxibustion Method were increased by average the $1^{\circ}C$. We have evaluated that the Drug-Pad Moxibustion Method is improvement on the conventional Indirect Moxibustion Method by the heat-increasing rate is 200% and the lasting time is 150% with the body heat of the abdominal region. In the conclusions, We have implemented the Drug-Pad Moxibustion Method and evaluated the efficiency of the Drug-Pad Moxibustion Method comparing with the conventional Indirect Moxibustion Method.

• Journal of the Korean Magnetics Society
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• v.11 no.4
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• pp.141-145
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• 2001

The Mn$\_$80/Ir$\_$18.1/Pt$\_$1.9/ exchange bias layers (EBLs), which have a small amounts of Pt, exhibit a high value of H$\_$ex/. The Si/Ni-Fe/Mn$\_$80/Ir$\_$18.1/Pt$\_$1.9/ EBL shows the largest H$\_$ex/ of 187 Oe, which is equivalent to a exchange energy (J$\_$ex/) of 0.146 erg/cm$^2$. Mn$\_$80/Ir$\_$18.1/Pt$\_$1.9/ EBLS are estimated to have blocking temperature of about 250 $\^{C}$, which is higher than those of Mn-Ir EBLs and Mn-Ir-Pt EBLs with higher Pt contents. This result implies that a little addition of Pt element promotes thermal stability in the Mn-Ir-Pt EBLs. The chemical stability of Mn-Ir-Pt EBLs was characterized by potentiodynamic test, which was performed in 0.001 M NaCl solution. The current density of Mn-Ir-Pt films was gradually reduced with increasing Pt content. The present results indicate that the Mn-Ir-Pt with a small amount of Pt is suitable for an antiferromagnetic material for a reliable spin valve giant magnetoresistance device.

• Archives of Pharmacal Research
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• v.20 no.3
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• pp.253-258
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• 1997

Ten, heretofore unreported, $ 5^I-methyl-5^I-[2-(5-substituted uracil-1-yl)ethyl)]-2^I-oxo-3^I$-methylenetetrahydrofurans (H, F, Cl, Br, I, $ CH_3$,$CF_3$,$CH_2CH_3$,$ CH=CH2$, SePh) (7a-j) were synthesized and evaluated against four cell lines (K-562, FM-3A, P-388 and U-937). For the preparation of ${\alpha}$-methylene-${\gamma}$-butyrolactone-linked to 5-substituted uracils (7a-j), the convenient Reformasky type reaction was employed which involves the treatment of ethyl ${\alpha}$-(bromomethyl)acrylate and zinc with the respective 1-(5-substituted uracil-1-yl)-3-butanone (6a-j). The 5-substituted uracil ketones (6a-j) were directly obtained by the respective Michael type reaction of vinyl methyl ketone with the $K_2CO_3$(or NaH)-treated 5-substituted uracils (5a-j) in the presence of acetic acid in the DMF solvent. The .alpha.-methylene-.gamma.-butyrolactone compounds showing the most significant antitumor activity are 7e, 7f, 7h and 7j (inhibitory concentration $(IC_50)$ ranging from 0.69 to $2.9 {\mu}g/ml$), while 7b, 7g and 7i have shown moderate to significant activity. The compounds 7a, 7c and 7d were found to be inactive. The synthetic intermediate compounds 6a-j were also screened and found marginal to moderate activity where compounds 6b and 6g showed significant activity $(IC_50:0.4~2.8 {\mu}g/ml)$.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.123-123
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• 2010

3족 질화물계 물질은 발광다이오드와 같은 광전자소자적용에 있어서 매우 우수한물 질이다.일반적으로, GaN 에피 성장에 있어서 저온 중간층을 삽입한 2 단계 성장 방법은 낮은 결함밀도와 균일한 표면을 얻기 위해 도입된 기술이다. 특히 AlN 중간층은 GaN 중간층과 비교하였을 때 결정성뿐만 아니라 높은 온도에서의 열적안정성, GaN 기반의 자외선 검출기서의빛 흡수 감소 등의 장점을 가지고 있다. 또한 패턴 사파이어 기판위 GaN 에피 성장은 측면성장 효과를 통해 결함 밀도 감소와 광 추출 효율을 향상시키는 것으로 알려져 있다.또한 열응력으로 인한 기판의 휨 현상은 박막성장중 기판의 온도 분포를 불균일하게 만드는 원인이 되며 이는 결국 박막 조성 및 결정성의 열화를 유도하게 되고 최종적으로 소자특성을 떨어 뜨리는 원인이 되는데 AlN 중간층의 도입으로 이것을 완화시킬 수 있는 효과가 있다. 하지만, AlN 중간층이 패턴된 기판 위에 성장시킨 GaN 에피층에 미치는 영향은 명확하지 않다. 본 연구팀은 일반적인 c-plane 사파이어 기판과 플라즈마 건식 에칭을 통한 렌즈 모양의 패턴된 사파이어 기판을 이용해서 AlN 중간층과 GaN 에피층을 유기금속 화학기상증착법으로 성장하였다. 특히, 렌즈 모양의 패턴된 사파이어 기판은 패턴 모양과 패턴 밀도가 성장에 미치는 영향을 연구하기 위해 두가지 패턴의 사파이어 기판을 이용하였다. AlN 중간층 두께를 조절함으로써 최적화된 GaN 에피층을 90분까지 4단계로 시간 변화를 주어 성장 양상을 관찰한 결과, GaN 에피박막의 성장은 패턴 기판의 trench 부분에서 시작하여 기판의 패턴부분을 덮는 측면 성장을 보이고있다. 또한 TEM과 CL을 통해 GaN 에피박막의 관통 전위를 분석해 본 결과 측면 성장과정에서 성장 방향을 따라 옆으로 휘게 됨으로 표면까지 도달하는 결정결함의 수가 획기적으로 줄어드는 것을 확인함으로써 고품질의 GaN 에피층을 성장시킬 수 있었다. 그리고 패턴밀도가 높고 모양이 볼록할수록 측면 성장 효과로 인한 결정성 향상과 난반사 증가를 통한 임계각 증가로 광추출 효율이 향상 되는 것을 확인할 수 있었다. 이러한 결과를 바탕으로 최적화된 AlN 중간층을 이용하여 패턴 기판위에서 고품질의 GaN 에피층을 성장시킬 수 있었다.