• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.18-20
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• 2007

3상 계통 연계 형 인버터 시스템은 낮은 THD를 가지는 계통 전류를 공급해주기 위해 LCL 필터를 사용한다. LCL 필터를 사용하는 가장 큰 장점은 낮은 스위칭 주파수에서도 만족할 만한 수준의 THD를 가지는 계통 전류를 생성시킬 수 있다는 점이다. 반면에, 단점은 LCL필터를 포함하는 계통 연계 형 인버터 시스템의 전달함수에 하나의 공진 극점이 존재한다는 점이다. 이것은 계통 전류 제어 loop에서, 안정성 문제에 영향을 미친다. 정확한 제어를 위해서 시스템의 전달함수는 필수적이다. 여기서 중요한 점은 많은 저자들이 시뮬레이션과 실험을 할 때, 중성점이 없는 회로에서 행하지만 회로 해석을 할 때에는 중성점이 있는 회로에서 해석을 한다는 점이다. 그래서 우리는 등가 델타회로에서 LCL 필터를 포함한 전체 시스템의 수학적인 모델을 제안한다. 이 모델은 모든 인덕터와 커패시터의 기생 저항을 고려한다. 또한 이 논문은 계통 전류를 제어하기 위한 제어기의 해석적인 설계 절차를 포함한다. 제안한 수학적인 모델을 입증하기 위해, PSIM을 통한 시뮬레이션과 Simulink를 통한 시뮬레이션 결과를 비교하였다.

• Clinical and Experimental Pediatrics
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• v.46 no.4
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• pp.376-381
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• 2003

Purpose : This study aimed to demonstrate the possible pathogenesis of granulopoiesis in patients of Kawasaki disease(KD) using quantitative analysis of G-CSF, GM-CSF and their CSFr. Methods : The plasma levels of G-CSF, GM-CSF, G-CSFr and GM-CSFr were studied in 14 patients in the acute phase of KD; 13 children with normal peripheral white blood cell counts were used as the normal control group. The plasma concentration of G-CSF, GM-CSF were analyzed by ELISA. The G-CSFr and GM-CSFr on the peripheral granulocytes were analyzed by a quantitative flow cytometric assay and QuantiBRITE, and the quantitative changes of receptors which did not combine with G-CSF and GM-CSF were measured. Results : The total number of leukocytes in KD was similar to normal control group, but the leukocytes increased according to the number of neutrophils. The plasma concentration of G-CSF were decreased similar to normal control group(P=0.133), but that of GM-CSF decreased more than the normal control group(P=0.227). The quantity of G-CSFr, GM-CSFr were revealed to be no less than the normal control(P=0.721, P=0.912). After incubation with excessive G-CSF, the expressed G-CSFr on the neutrophils were decreased in both groups(P=0.554). The quantities of expressions of GM-CSFr on the neutrophil after incubation with the excessive GM-CSF were always increased in both groups(P=0.255). The amount of GM-CSFr of neutrophils are in proportion to total white blood cells (r=0.788, P=0.035), but it wasn't in the case of KD(P=0.644). Conclusion : The leukocytosis in KD that mediated by increasing neutrophil was not correlated with the plasma concentrations of G-CSF and GM-CSF, and the amount of expression of G-CSFr and GM-CSFr on granulocyte. It is possible that the reduction of concentration of GM-CSF results by increasing the active GM-CSFr.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.2
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• pp.15-29
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• 2020

The aims of this study is to improve physical properties of the sewage sludge and the process sludge generated in the leachate treatment by mixing the dry fuel, to develop the neutral solidifing agents that reduce oder, and to recycle the sewage and the process sludges as landfill cover materials. The mixing ratio (W/W) of sludges and dry fuel was appropriate at about 1:1, and the mixed materials were shown to be homogeneous at that ratio. We could know that when the sludges were mixed with dry fuel, moisture contents and viscosities are reduced, and air passages are formed between particles and particles. The various mixing tests and odor tests showed that the neutral solidifing agent was effective for the odor reduction. The main ingredient of the solidifing agent is the ash of sewage sludge, enabling it competitive in waste recycling and production costs. The landfill cover, using developed neutral solidification agent, improved physical properties to satisfy the quality standards and to increase the compressive strength. It also proved to reduce the value of complex oder and the usage of solidification agent to 1/3 (3,000 to 1,000) and to 1/8 (50% to 6%), respectively, from the comparative study with alkaline solidified landfill cover. Further research is under way to prove that this can be mixed with general soil to be used as a soil improvement agent for plant cultivation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.12
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• pp.1763-1770
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• 2015

The effects of root of Taraxacum coreanum Nakai (TC), on the suppression of inflammation and oxidative stress induced by lipopolysaccharide (LPS) in ICR mice were studied. LPS (10 mg/kg body weight) was injected into ICR mice in between two consecutive oral administrations. Hot water extract of fresh TC (HWETC) was administered to mice immediately before and 24 h after LPS injection. The animal groups used in this study were as follows: NOR group (PBS injection, DW administration), CON group (LPS injection, DW administration), and TC group (LPS injection, 1.4 g/kg bw of HWETC administration). Mice in the CON group lost weight due to inflammation induced by LPS, while the body weight of the TC group mice increased significantly, indicating that inflammation was inhibited by HWETC administration. Compare with the CON group, plasma and hepatic triglyceride, reactive oxygen species, peroxynitrite, and hepatic thiobarbituric acid reactive substances concentrations of the TC group decreased significantly (P<0.05). The protein expression of a pro-inflammatory transcription factor, nuclear $factor-{\kappa}B$ ($NF-{\kappa}B$) and its target enzyme, cyclooxygenase 2, increased in response to LPS injection, but was suppressed by HWETC administration (P<0.05). In conclusion, HWETC appears to ameliorate the oxidative stress and inflammatory responses induced by LPS via inhibition of $NF-{\kappa}B$ activation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.3
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• pp.236-240
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• 1992

To obtain the applicable data for fish oil utilization, the characteristics of filefish viscera oil were studied. The lipid content showed the lowest value$(38.8\%)$ from viscera of filefish caught in April and the highest value$(59.5\%)$ in July. The seasonal variation in fatty acids showed a tendency of high level of polyenes such as 20:5 and 22:6 and low level of saturates such as 16:0 and 18:0 during the spawning season. While level of monoenes such as 18:1 was low regardless of seasons. The viscera of filefish caught in April contained $46.7\%$ total lipid(TL) which consisted of $94.3\%$ neutral lipid(NL), $1.6\%$ glycolipid(GL) and $4.1\%$ phospholipid(PL). The NL of filefish viscera mainly consisted of triglyceride$(88.1\%)$ and had esterified sterol and hydrocarbon, free sterol, diglyceride and free fatty acid in less quantity. The major fatty acids in TL and NL were 16:0, 18:0, 18:1, 20:5 and 22:6.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.243-243
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• 2012

화석연료를 대체할 새로운 청정 에너지원의 요구가 높아지고 있는 현 시점에서 고효율, 무공해, 무소음 등의 장점으로 인해 친환경적 에너지원으로 연료전지의 수요가 증가하고 있다. 연료전지 분리판으로 고밀도 흑연을 종래에 가공하여 제작하였는데, 가공이 어렵고, 비용이 크게 들며, 대량생산이 어렵다는 등의 문제로 스테인리스강을 위주로 한 금속 분리판 개발이 이루어지고 있다. 본 연구에서는, 낮은 가격, 고속 증착, 우수한 가공성, 높은 기계적 강도 및 전기전도도, 화학적 안정성 및 내식성을 충족시키기 위하여 스테인리스 강박(0.1 mm이하)에 보호막으로 CrN을 선택하였다. 저가격화를 위하여 새로운 증착원인 스퍼터-승화형 소스의 가능성을 유도 결합 플라즈마에 Cr 봉을 직류 바이어스 함으로써 시도하였다. 10 mTorr의 Ar 유도 결합 플라즈마를 2.4 MHz, 400 W로 유지하면서 직류 바이어스 전력을 120 W (615 V, 0.19 A) 인가하였을 때 10분 동안의 증발양이 0.35 gr으로 측정이 되어 그 가능성을 확인할 수 있었다. 또한 OES(Optical emission spectrometer)를 이용하여 RPS로 방전시킨 고밀도 ICP를 측정한 결과 842.4 nm, 811.4 nm, 772.3 nm 등의 파장에서 높은 intensity를 갖는 peak을 찾을 수 있었고, 이 peak 들은 Ar 중성의 peak임을 확인할 수 있었다. ICP+DC bias로 Cr rod를 가열하는 공정에서의 plasma를 OES로 측정한 결과 Ar 중성의 peak은 감소하고, 520.5 nm, 425.5 nm, 357.7 nm 등의 파장에서 높은 intensity를 갖는 peak을 찾을 수 있었으며, 이 peak들은 Cr 중성의 peak임을 확인할 수 있었다. OES 측정 data를 토대로 공정 중의 rod type Cr target의 교체 주기를 예측할 수 있고 공정 중 실시간 감시가 가능할 것으로 기대된다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.2
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• pp.71-75
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• 2006

The aggregates made of clay, carbon and $Fe_2O_3$ were prepared to investigate the mechanism of black core formation and the property differences at various sintering atmospheres. The aggregates were sintered at oxidized, neutralized and reduced atmospheres. The specific gravity, absorption rate, percent of black core area were measured at various compositions and sintering atmospheres. The aggregates sintered at oxidized atmosphere showed clear border between shell and black core area. Hence, the aggregates sintered at reduced and neutralized atmospheres showed only black core area in the cross-section of the aggregates. The specific gravity of the aggregates sintered at reduced atmosphere increased with increasing carbon contents and that was the lowest of all aggregates sintered at various atmospheres. Adsorption rate increased with increasing carbon contents at all atmospheres.

• Fire Science and Engineering
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• v.22 no.4
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• pp.20-26
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• 2008

The performance of natural smoke ventilators in High-rise buildings was analyzed by investigating the stack effect depending on the wind velocities using CONTAMW tool. The results showed that the opening of smoke ventilators can influence on the stack effect in the building thus moving the position of the neutral plane toward the opened smoke ventilators. The outside wind velocities can move up the neutral plane toward the top of the building thus increasing pressure differentials at the bottom of the building. The smoke ventilators can maintain its normal performance without outside wind, however, strong outside wind can prevent natural smoke exhaust due to the infiltration of outside air at the ventilators.

• Journal of the Korean Society of Tobacco Science
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• v.2 no.2
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• pp.8-13
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• 1980

The inhibition effect of flavone and butylatedhydroxyanisole (BHA) on the microsomal activation of Cigarette Smoke Condensate (CSC) or its Neutral Portion (NP) was investigated in Rat. The activities of Latic acid dehydrogenase (LDH) in serum was measured in the time intervals of 3, 6, 12, 18, 24 and 30 hr, respectively, after the injection (ip) of CSC (5mg/kg) or NP (10mg/kg) to Wistar male rat. Flavone (1mg/kg) and BHA (1mg/kg) were injected along with CSC or NP. The significant enhancement of the LDH activity in serum was observed in both cases of rats treated with CSC and NP. A drastic decrease of LDH activity from 1040 unit to 641 unit was observed after 12 hours of injection of CSC along with flavone. In contrast with the case of flavone, BHA reduced the enzyme activity from 825 unit to 652 unit at the same condition of flavone. Therefore, flavone can be considered to be a better inhibitor on action of CSC in vivo.

• Journal of the Korean Vacuum Society
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• v.7 no.4
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• pp.390-396
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• 1998

Neutral stream was generated from Helicon plasma source and was applied to etch silicon for the purpose of preventing physical and electrical damages from the bombardment of charged particles with high translation energy. By installing a permanent magnet and applying positive bias beneath the substrate, the cusp-magnetic and electric fiddles were generated in order to remove the charged particles from the downstream plasma. As a result, the electron density and ion density in the vicinity of the substrate were reduced by 1/1000 and 1/10, respectively. The directional etching of silicon was observed and the etch rate was found to be very low to below 100 $\AA$/min at a pressure of $8.5{\times}10^{-4}$ Torr, when $Cl_2$ and 10% $SF_{sigma}$ etchant gases were used.