• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.124-124
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• 2000

다이아몬드에 버금가는 높은 경도뿐만 아니라 높은 화학적 안정성 및 열전도성 등 우수한 물리화학적 특성을 가진 입방정 질화붕소(cubic boron nitride)는 마찰.마모, 전자, 광학 등의 여러 분야에서의 산업적 응용이 크게 기대되는 재료이다. 특히 탄화물형성원소에 대해 안정하여 철계금속의 가공을 위한 공구재료로의 응용 또한 크게 기대된다. 이 때문에 각종의 PVD, CVD 공정을 이용하여 c-BN 박막의 합성에 대한 연구가 광범위하게 진행되어 많은 성공사례들이 보고되고 있다. 그러나 c-BN 박막의 유용성에도 불구하고 아직 실제적인 응용이 이루어지지 못한 것은 c-BN 박막의 증착직후 급격한 박리현상 때문이다. 본 연구에서는 평행자기장을 부가한 ME-ARE(Magnetically Enhanced Activated Reactive Evaporation)법을 이용한 c-BN 박막의 합성에서 적용한 증착공정 인자들의 변화에 따른 박리특성 고찰과 함께 다층박막화 및 제 3원소 혼입 방법을 적용하여 박리특성 향상 정도를 조사하였다. BN 박막합성은 전자총에 의해 증발된 보론과 (질소+아르곤) 플라즈마의 활성화반응증착(Activated Reactive Evaporation)에 의해 이루어졌다. 기존의 ARE 장치와 달리 열음극(got cathode)과 양극(anode) 사이에 평행자기장을 부가하여 플라즈마의 증대시켜 반응효율을 높였다. 합성실험용 모재로는 p-type으로 도핑된 (100) Si웨이퍼를 30$\times$40mmzmrl로 절단 후, 10%로 희석된 완충불산용액에 10분간 침적하여 표면의 산화층을 제거한 후 사용하였다. 박막실험실에서의 주요공정변수는 기판바이어스 전압, discharge 전류, Ar/N2가스유량비이었다. 합성된 박막의 결정성 분석을 FTIR을 이용하였으며, BN 박막의상 및 미세구조관찰을 위해 투과전자현미경(TEM;Philips EM400T) 분석을 병행하였고, 박막의 기계적 물성 평가를 위해 미소경도를 측정하였다. 박리특성의 고찰은 대기중에서의 자발적 박리가 일어나 90%이상의 박리가 진행된 시점까지의 시간을 측정하였고, 증착직후 박막의 잔류응력 변화와 연관하여 고찰해 보았다.

• Journal of Korean Society on Water Environment
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• v.22 no.3
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• pp.521-526
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• 2006

We have studied the possibility of removing Anabaena macrospora by injecting copper sulfate ($CuSO_4{\cdot}5H_2O$) into the raw water of a drinking water purification plant. Anabaena macrospora caused the unpleasant geosmin odor of drinking water in August 2001. The cell break-point of A. macrospora was 0.3 mg/L of $CuSO_4$. We were able to reduce the standing crops of A. macrospora effectively because $CuSO_4$ could break A. macrospora selectively. Because 0.3 mg/L of $CuSO_4$ could break both cells and akinetes, it reduced the possibility of a recurrent problem for them to meet a favorable condition. When $CuSO_4$ was injected in the early growth phase of algae and the mixing intensity was high, A. macrospora could be removed most effectively. The odor caused by A. macrospora was sustained for a while without any sudden change of environmental condition. Therefore, we hope that it could shorten the period of obstacle by injecting the optimal amount of 0.3 mg/L of $CuSO_4$. The water quality, alkalinity, conductivity, hardness and pH didn't changed by the injection of $CuSO_4$.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.1
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• pp.1-14
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• 2021

Eutrophication and algal blooms can lead to increase of taste and odor compounds and health problems by cyanobacterial toxins. To cope with these eco-social issues, Ministry of Environment in Korea has been reinforcing the effluent standards of wastewater treatment facilities. As a result, various advanced phosphorus removal processes have been adopted in each wastewater treatment plant nation-widely. However, a lot of existing advanced wastewater treatment processes have been facing the problems of expensive cost in operation and excessive sludge production caused by high dosage of coagulant. In this study, the sedimentation and dissolved air flotation (SeDAF) process integrated with sedimentation and flotation has been developed for enhanced phosphorus removal in wastewater treatment facilities. Design and operating parameters of the SeDAF process with the capacity of 100 ㎥/d were determined, and a demonstration plant has been installed and operated at I wastewater treatment facility (located in Gyeonggi-do) for the verification of field applicability. Several empirical evaluations for the SeDAF process were performed at demonstration-plant scale, and the results showed clearly that T-P and turbidity values of treated water were to satisfy the highest effluent standards below 0.2 mg/L and 2.0 NTU stably for all of operation cases.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.2
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• pp.137-144
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• 1996

A feasible way to utilize small-scale livestock farm wastewater was explored. In place of common support materials rice straw was employed as a support medium of trickling filter for pig farm wastewater treatment. The straw medium which was humified for 20 days after wastewater treatment and mixed with soil significantly enhanced in general the development of bunching lettuce grown under greenhouse conditions. Improvement of soil chemical properties in terms of fertility was also achieved by the addition of humified straw medium after wastewater treatment. It was found that rice straw served as a satisfactory support medium of trickling filters with the wastewater treatment concerning removals of biological oxygen demand, chemical oxygen demand, and suspended solids.

• Korean Journal of Environment and Ecology
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• v.25 no.1
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• pp.10-16
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• 2011

This study was carried out to analyze the vegetation and soil characteristic, and ordination of the Ilex cornuta population, in the Yongsu Reservoir of Jeju Island. The Ilex cornuta population was classified into Cudrania tricuspidata dominant population, Sageretia theezans dominant population, and Mallotus japonicus dominant population. In the study sites, soil organic matter(O.M.), total nitrogen(T.N.), available phosphorus($P_2O_5$), changeable potassium, changeable calcium, changeable magnesium and soil pH were 14.62~17.35%, 0.39~0.51%, 8.83~20.15mg/kg, 0.44~0.64cmol+/kg, 5.79~6.87cmol+/kg, 3.43~4.19cmol+/kg and 5.41~5.80, respectively. The Mallotus japonicus dominant population was mainly found in the high percentage of available phosphorus, organic matter. It was also showed the lowest concentration of exchangeable K, and Mg. Cudrania tricuspidata dominant population and Sageretia theezans dominant population were found in the low percentage of available phosphorus, organic matter and there were also showed the highest concentration of exchangeable K, and Mg. It is one of the evidence that Ilex cornuta community indicated an intensive site management likes clearance of creeper is proper habitat management protocol. Thus, further researches should be followed to determine the other disturbance factors as management techniques.

• KSBB Journal
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• v.15 no.2
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• pp.113-119
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• 2000

In order to produce xylitol with high yield, experiments were carried out to develope xylitol dehydrogenase (XDH) defective m mutant from Pichia stipitis and to investigate the xylit이 fermentation characteristics of mutant strain. After treatment of P s stipitis with EMS, mutant PXM-4 was selected based on the XDH activity and xylitol production capability. Among the tested c cosubstrates, galactose was selected as an adequate cosubstrate on xyl뻐I production of mutant PXM-4. With the increase of galactose concentration, xylitol production was decreased because the transport of xylose into cell was inhibited by g galactose. The optimal concentration of galactose for the production of xylitol using 20 g/L xylose was 20 g/L. Under this c condition, maximum concentration of xylitol and yield were 14.4 g/L and 97%, respectively. In order to prevent the inhibitory e effect of xylose transport by galactose, galactose was fed with low concentration and the concentration of xylitol produced w was increased up to 25 g/L. In the fermentation of corn cob hydrolyzate by mutant PXM-4, xylose was completely converted t to xylit이 with a 100% yield in 4 days culture.

• Journal of Life Science
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• v.26 no.7
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• pp.805-811
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• 2016

The present study was performed to evaluate the anti-oxidant and anti-proliferating activity of the water extract mixture of Cordyceps militaris (CM) and Allium tuberosum (AT). The water extract mixture rate of CM and AT was optimized by means of a sensory evaluation test. The optimized mixture rate were decided at 70% of CM, 30% of AT, and 10% of apple concentrate as an additive. The values of total acidity, pH, sugar contents, and turbidity of the water extract mixture were 0.1%, 4.28, 9.10 °Brix, and 1.48 respectively. The water extract mixture had effective DPPH radical scavenging activity, reducing power effect, and ABTS radical activity. DPPH radical activities of the water extract and the water extract mixture were 43.2% and 51.7% respectively; their reducing power (OD₇₀₀) was 1.14 and 1.43 respectively; and ABTS^.+ radical activities were 47.1% and 62.2% respectively. Also, the water extract mixture showed a higher anti-proliferating effect than the AT extract on human prostate cancer cells. These results provided experimental evidence that the water extract mixture of CM and AT is a better source of anti-oxidant and anti-cancer ingredients than a single extract of CM. In conclusion, the water extract mixture of CM and AT will be beneficial in development of a functional drink.

• The korean journal of orthodontics
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• v.31 no.5 s.88
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• pp.517-523
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• 2001

Titanium miniscrews we being used increasingly as an anchorage for tooth movement, because they ate easy to place and to remove, increase the number of sites available, give minimum strain to patients regarding surgical procedures, and offer uneventful healing alter removal. The use of titanium miniscrews as an orthodontic anchorage has been reported in clinical case reports, but clinicians have experienced screw loosening when using such screws.' To our knowledge, there are no published reports evaluating the stability of miniscrews. Information about the length of miniscrews used in relation to the location is of some importance, as stability will vary depending on bone duality The purpose of this study was to evaluate a variety of Lengths of miniscrews (dimeter: 2mm) which were inserted in maxilla or mandible and to demonstrate in a dog model which miniscrew provides fundamental stability in the jaws. 10 mm long miniscrews in the maxilla and 8mm long: miniscrews in the mandible showed no clinical mobility and retained their position throughout an 8 weeks force (200g) application. The mucosal condition around the screws was healthy in cases in which miniserews were inserted in the alveolar bone between the roots and the head of the screws emerged into the attached gingiva. When the force application was terminated, radiographic analysis revealed neither rent resorption not periodontal pathology around the miniscrews that remained stable during the entire treatment period. This study suggests that if titanium miniscrews with adequate length are properly used depending on the location, they provide sufficient stability for orthodontic anchorage.

• Development and Reproduction
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• v.5 no.1
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• pp.73-79
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• 2001

Recently many studies have reported that total and bioavailable androgens reduced in male and female athletes and that physical exercise reduces the body weight and increases the reproductive abnormalities such as oligomenorrhea, anovulation, inadequate luteal phase, and delayed puberty in women by the inhibition of the hypothalamic-pituitary-gonadal (HPG) axis . In addition, high mileage endurance 겨nning, psychological stress, and military endurance training in men also reduce the secretion of reproductive hormones. To investigate the efffcts of physical endurance exercise on the secretion of reproductive hormones in men, androgenic hormones from adrenal glands and testis were measured in serum by the conventional radioimmunoassays after long-term (more than3 months), short-term (1 week), and acute (1${sim}$2 hours) physical exercises. Androgenic hormones from adrenal glands and testis such as total testosterone (TT), free testosterone (fT), dehydroepiandrosterone (DHEA), and androstenedione (A) decreased after thesestrenuous endurance trainings, whereas ACTH, cortisol, and dehydroepiandrosterone sulfetes (DHEAS) increased. Conadotropins (LH and FSH) were not idluenced by the physical exercises. Based upon the present results, we assume that the decrease in adrenal and testicular androgens by physical endurance exercises might be associated with the reproductive abnormalities in athletes by unknown factor(s) in addition to the HPG axis disturbance.

• The Korean Journal of Nuclear Medicine
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• v.37 no.6
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• pp.402-417
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• 2003

Purpose: To evaluate the use of monoclonal antibody (MoAb) as a carrier of the receptor-binding ligand the receptor mediated uptake into liver and subsequent metabolism of $^{111}In-labeled$ galactosylated MoAb-chelator conjugates were investigated and compared with those of $^{111}In$ labeled MoAb. Materials and Methods : T101 MoAb, $IgG_2$ against human lymphocytic leukemic cell, conjugated with cyclic DTPA dianhydride (DTPA) or 2-p-isothiocyanatobenzyl-6-methyl-DTPA (1B4M) was galactosylated with 2-imino-2-methoxyethyl-1-thio-${\beta}$-D-galactose and then radiolabeled with $^{111}In$. Biodistribution and metabolism study was peformed with two $^{111}In-conjugates$ in mice and rats. Results: $^{111}In-labeled$ T101 and its galactosylated conjugates were taken to the liver by the time, mostly within 10 min. However DTPA conjugate was retained longer in the liver than the 1B4M conjugate (55% vs 20% of injected dose at 44 hr). During this time, the radiornetabolite of DTPA conjugate was excreted similarly into urine (24%) and feces (17%). The radiometabolite of 1B4M was excreted primarily into feces (68%) rather than urine (8%). Size exclusion HPLC analysis of the bile and supernatant of liver homogenate showed two peaks the first (35%) with the retention time (Rt) identical to IgG and the second (65%) with Rt similar to free $^{111}In$ at 3 hr post-injection for the 1B4M conjugate, indicating that the metabolite is rapidly excreted through the biliary system. in contrast to DTPA conjugate, the small $^{111}In-DTPA-like$ metabolite was the major radioindium component (90%) in the liver homogenate as early as 3 hour post-injection, but the cumulative radioindium activity in feces was only 17% at 44 hour, indicating that the metabolite from DTPA conjugate does not clear readily through the biliary tract. Conclusion: The galactosylation of the MoAb conjugates resulted in higher hepatocyte uptake and enhanced metabolism, compared to those without galactosylation. Metabolism of the MoAb-conjugates is different between compounds radiolabled with different chelators due to different characteristics of radiometabolites generated in the liver.