• E2M - 전기 전자와 첨단 소재
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• 제10권1호
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• pp.26-32
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• 1997

The gate induced drain leakage(GIDL) current under the stress of worse case in -MOSFET's with ultrathin gate oxides has been measured and characterized. The GIDL current was shown that P-MOSFET's of the thicker gate oxide is smaller than that of the thinner gate oxide. It was the results that the this cur-rent is decreased with the increamental stress time at the same devices.It is analyzed that the formation components of GIDL current are both energy band to band tunneling at high gate-drain voltage and energy band to defect tunneling at low drain-gate voltage. The degradations of GIDL current was analyzed the mechanism of major role in the hot carriers trapping in gate oxide by on-state stress.

• 대한환경공학회지
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• 제34권10호
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• pp.709-714
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• 2012

본 연구에서는 석탄계 활성탄 신탄을 이용하여 입상활성탄 흡착공정에서의 nitrosamine류 9종의 흡착특성을 평가해 본 결과, nitrosamine류 9종의 물질별 파과 순서는 NDMA가 가장 빨리 파과에 도달하였고, 다음으로 NMOR, NPYR, NMEA, NDPA, NDEA, NPIP 순으로 나타났고, NDBA와 NDPHA의 경우는 운전 기간 동안 활성탄 처리수에서 검출되지 않았다. 석탄계 활성탄 신탄을 이용한 입상활성탄 흡착공정에서의 nitrosamine류 9종의 최대 흡착량(X/M)은 파과에 도달한 nitrosamine류 7종 중에서 NDMA가 $27.5{\mu}g/g$으로 가장 낮게 나타났으며, NPIP가 $671.0{\mu}g/g$으로 가장 높은 최대 흡착량을 나타내었고, NDBA와 NDPHA의 경우는 실험기간 동안 활성탄 흡착컬럼의 처리수에서 검출되지 않아 최대 흡착량을 구할 수가 없었다. 또한, 7종의 nitrosamine류에 대한 CUR의 경우는 NDMA가 1.07 g/day로 나타나 NPIP의 0.08 g/day 보다 13.4배 정도 높은 활성탄 사용률을 나타내었다. 석탄계 활성탄 신탄을 이용한 입상활성탄 흡착공정에서 파과에 도달한 7종의 nitrosamine류에 대해 최대 흡착량(X/M)과 $K_{ow}$값과의 상관성을 평가해 본 결과, 상관계수($r^2$)가 0.94로 나타나 양호한 상관성을 나타내었다.

• 대한환경공학회지
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• 제30권4호
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• pp.401-408
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• 2008

입상활성탄 재질별 신탄에서의 sulfonamide계 항생물질 5종에 대한 파과특성의 경우 석탄계 활성탄이 가장 늦게 파과에 도달하였으며, 다음으로 야자계, 목탄계 순으로 조사되었다. 또한, 물질별 활성탄에서의 파과특성을 살펴보면 sulfachloropyridazine(SCP)의 파과시점이 가장 늦은 것으로 나타났으며, 다음으로 sulfathiazole(STZ), sulfadimethoxine(SDM), sulfamethazine(SMT), sulfamethoxazole(SMX)로 나타났다. 활성탄 g당 sulfonamide계 항생물질 5종에 대한 최대 흡착량(X/M)은 석탄계 활성탄이 가장 높은 것으로 나타났으며, 다음으로 야자계와 목탄계 순으로 나타났다. sulfonamide계 항생물질 5종에 대한 석탄계 활성탄의 최대 흡착량(X/M)은 야자계와 목탄계 활성탄에 비해 각각 1.3$\sim$1.5배 및 1.8$\sim$2.1배 정도 높은 것으로 조사되었다. 활성탄에서의 흡착용량을 나타내는 k값의 경우 활성탄 재질별로는 석탄계 활성탄이 가장 크게 나타났으며, 다음으로 야자계, 목탄계 활성탄 순으로 조사되어 석탄계 활성탄이 각각의 sulfonamide계 항생물질들에 대해 가장 큰 흡착용량을 가지는 것으로 조사되었다. 또한, 5종의 sulfonamide계 항생물질별로는 SCP가 전반적으로 다른 sulfonamide계 항생물질 4종에 비해 활성탄 재질별로 가장 큰 k값을 나타내었으며, 다음으로 STZ, SDM, SMT, SMX 순의 경향을 나타내었다. 활성탄 사용율(carbon usage rate, CUR)은 SCP의 경우 석탄계 재질의 활성탄이 3.55 g/일, 야자계나 목탄계 활성탄은 각각 4.29 g/day 및 6.47 g/day의 활성탄을 사용하여야만 제어가 가능한 것으로 조사되어 석탄계 활성탄이 다른 재질의 활성탄들에 비해 적은 양으로도 sulfonamide계 항생물질을 제어할 수 있는 것으로 나타났으며, 나머지 sulfonamide계 항생물질 4종에서도 이와 유사한 결과를 나타내었다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권sup3호
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• pp.219-224
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• 2016

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver making up more than 80 percent of cases. It is known to be the sixth most prevalent cancer and the third most frequent cause of cancer related death worldwide. Epigenetic regulation constitutes an important mechanism by which dietary components can selectively activate or inactivate target gene expression. The miR-34 family members including mir-34a, mir-34b and mir-34c are tumor suppressor micro RNAs, which are expressed in the majority of normal tissues. Several studies have indicated silencing of miR-34 expression via DNA methylation in multiple types of cancers. Bioactive nutrients like curcumin (Cur) have excellent anticarcinogenic activity and minimal toxic manifestations in biological systems. This compound has recently been determined to induce epigenetic changes. However, Cur is lipophilic and has a poor systemic bioavailability and poor absorption. Its bioavailability is increased through employing dendrosome nanoparticles. The aim of the current study was to investigate the effect of dendrosomal nanocurcumin (DNC) on expression of mir-34 family members in two HCC cell lines, HepG2 and Huh7. We performed the MTT assay to evaluate DNC and dendrosome effects on cell viability. The ability of DNC to alter expression of the mir-34 family and DNA methyltransferases (DNMT1, DNMT3A and 3B) was evaluated using semi-quantitative and quantitative PCR. We observed the entrance of DNC into HepG2 and Huh7 cells. Gene expression assays indicated that DNC treatment upregulated mir34a, mir34b and mir34c expression (P<0.05) as well as downregulated DNMT1, DNMT3A and DNMT3B expression (P<0.05) in both HepG2 and Huh7 cell lines. DNC also reduced viability of Huh7 and HepG2 cells through restoration of miR-34s expression. We showed that DNC could awaken the epigenetically silenced miR-34 family by downregulation of DNMTs. Our findings suggest that DNC has potential in epigenetic therapy of HCC.

• 대한기계학회논문집B
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• 제27권10호
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• pp.1457-1463
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• 2003

In this paper, the response surface method using three-dimensional Navier-Stokes analysis to optimize the shape of a multi-blade centrifugal fan, is described. For numerical analysis, Reynolds-averaged Navier-Stokes equations with standard k - c turbulence model are transformed into non-orthogonal curvilinear coordinate system, and are discretized with finite volume approximations. Due to the large number of blades in this centrifugal fan, the flow inside of the fan is regarded as steady flow by introducing the impeller force models for economic calculations. Linear Upwind Differencing Scheme(LUDS) is used to approximate the convection terms in the governing equations. SIMPLEC algorithm is used as a velocity-pressure correction procedure. Design variables, location of cur off, radius of cut off, expansion angle of scroll and width of impeller were selected to optimize the shapes of scroll and blades. Data points for response evaluations were selected by D-optimal design, and linear programming method was used for the optimization on the response surface. As a main result of the optimization, the efficiency was successfully improved. It was found that the optimization process provides reliable design of this kind of fans with reasonable computing time.

• 한국유체기계학회 논문집
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• 제7권3호
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• pp.32-38
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• 2004

Shape of a multi-blades centrifugal fan is optimized by response surface method based on three-dimensional Navier-Stokes analysis. For numerical analysis, Reynolds-averaged Navier-Stokes equations with standard $k-{epsilon}$ turbulence model are transformed into non-orthogonal curvilinear coordinate system, and are discretized with finite volume approximations. Due to the large number of blades in this centrifugal fan, the flow inside of the fan is regarded as steady flow by introducing the impeller force models for economic calculations. Optimizations with and without constraints are carried out. Design variables, location of cur off, radius of cut off, expansion angle of scroll and width of impeller were selected to optimize the shapes of scroll and blades. Data points for response evaluations were selected by D-optimal design, and linear programming method was used for the optimization on the response surface. As a main result of the optimization, the efficiency was successfully improved. The correlation of efficiency with relative size of inactive zone at the exit of impeller is discussed as well as with average momentum fluxes in the scroll.

• 한국환경과학회지
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• 제24권1호
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• pp.65-71
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• 2015

This study accessed the adsorption characteristics of the 9 trihalomethanes (THMs) on coal-based granular activated carbon (GAC). The breakthrough appeared first for $CHCl_3$ and sequentially for $CHBr_2Cl$, $CHBr_3$, $CHCl_2I$, CHBrClI, $CHBr_2I$, $CHClI_2$, $CHBrI_2$, and $CHI_3$. The maximum adsorption capacity (X/M) for the 9 THMs with apparent breakthrough points ranged from $1,175{\mu}g/g$ (for $CHCl_3$) to $11,087{\mu}g/g$ (for $CHI_3$). Carbon usage rate (CUR) for $CHCl_3$ was 0.149 g/day, 5.5 times higher than for $CHCl_3$ (0.027 g/day).

• 복식
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• 제31권
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• pp.101-118
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• 1997

This research was carried out to sublimate our design with common sence so that the de-sign concept with our traditional chara-teristics can be acceptable in the world design area through re-creation works of tradition to be adoptable to modern concept. Form this survey the following could be derived. 1. in Korea designers should concern about the ration of skirt to jacket plait of Chima and string Koreum of hanbok. however they should pay more attention to string and color stripes to attract foreign customers in international market. It was found that koreans prefer the elegant and cur-vaceous design while foreigners demend edecor-ative design of Hanbok in addition to its el-egance and curvaeouseness. 2. It was also found that korean ramie fabric might be the most popular material for hanbok in Korea however silk and fine gauze might have to be used in international market. Generally it would be better to use the materials with natural and delicate feelings in Korea while the materials with gorgeous feel-ing in addition to natural and delicate feeling should be used in international market. 3, For the figures on Hanbok the embroidery figures and pictorial figures would be appropri-ate in Korea while it is necessary to develop the design with embroidery figures and gold foiled figures to satisfy the foreign customers. Accordignly it 8is required to develop the designers with figures with more elegant and gorgeous sence in both Korea and the world area.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.2157-2161
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• 2003

In this paper, the response surface method using three-dimensional Navier-Stokes analysis to optimize the shape of a forward-curved blades centrifugal fan, is described. For numerical analysis, Reynolds-averaged Navier-Stokes equations with standard k-e turbulence model are transformed into non-orthogonal curvilinear coordinate system, and are discretized with finite volume approximations. Due to the large number of blades in forward-curved blades centrifugal fan, the flow inside of the fan is regarded as steady flow by introducing the impeller force models for economic calculations. Linear Upwind Differencing Scheme(LUDS) is used to approximate the convection terms in the governing equations. SIMPLEC algorithm is used as a velocity-pressure correction procedure. Design variables, location of cur off, radius of cut off, expansion angle of scroll and width of impeller were selected to optimize the shapes of scroll and blades. Data points for response evaluations were selected by D-optimal design, and linear programming method was used for the optimization on the response surface. As a main result of the optimization, the efficiency was successfully improved. It was found that the optimization process provides reliable design of this kind of fans with reasonable computing time

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.775-778
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• 2000

Single point diamond turning technique fur optical crystals is reported in this paper. The main factors influencing the machined surface quality are discovered and regularities of machining process are drawn. Optical crystals have found more and more important applications in the field of modern optics. Optical crystals are mostly brittle materials of poor machinability. The traditional machining method is polishing which has many shortcomings such as low production efficiency, poor ability to be automatically controlled and edge effect of the workpiece. SPDT has been widely used in manufacturing optical reflectors of non-ferrous metals such as aluminum and copper which are easy to be machined for their proper ductility. But optical crystals being discussed here are characterized by their high brittleness which makes it difficult to obtain high quality optical surfaces on them. The purpose of cur research is to find the optimum machining conditions for ductile cutting of optical crystals and apply the SPDT technique to the manufacturing of ultra precision optical components of brittle materials. As a result, the cutting force is steady, the cutting force range is 0.05-0.08N. The surface roughness is good when spindle is above 1400rpm. and feed rate is small. The influence of depth of cut is very small.