• 전기학회논문지
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• 제65권10호
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• pp.1682-1687
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• 2016

Approximately 520thousand elevators are operating now in Korea, about 40% ~ 60% of the elevator power is generated. In this paper, by using the method of adding regeneration power of the elevator to the grid-tied photo voltaic inverter, PV generation that was dependant on the solar radiation was significantly improved. In order to confirm this, the regeneration power of the elevator has been simulated in 12% of the rating load, and measured the regeneration power of the elevator in the actual condition to assess the differences of it. The 5[kW] hybrid grid-tied photo voltaic invertor has been fabricated to conduct an experiment for the confirmation of the proposing method. The effectiveness of the proposing method has been reassured with the result of experiment that include the transfer interface part of the regeneration power of the elevator.

• 한국정보통신학회논문지
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• 제16권6호
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• pp.1141-1147
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• 2012

본 논문에서는 Debye 분산 특성을 가지는 복제 방지용 PUF를 설계하기 위한 전자계 해석 방안을 고려하였다. 공기층과 유전체 기판 위에 형성된 분산매질(Si)로 구성된 1차원 모델 내에 전파하는 펄스를 모형하기 위해 FDTD법을 이용하였다. 불연속 경계면에 도달한 펄스는 일부 반사되고 일부는 투과되어 빠르게 감쇠되는 것으로 나타났다. 그 결과 FDTD법에 의한 유전체 기판을 고려한 Debye 분산특성을 가지는 1차원 복제방지용 PUF 모델링에 적용 가능한 것을 확인하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.934-937
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• 2007

This study focused on investigating the effect of aligned cellulose fibers to the performance of EAPap actuator. The performance of EAPap is dependant on the material direction of cellulose film. Electrospinning was used to improve material directionality of EAPap. DMAc cellulose solution which cotton pulp was resolved in DMAc solvent was used for electrospinning cellulose film. To increase directionality of nano fibers, the Electrospun film was stretched by 10 % strain during drying process. Induced in-plane strain of Electrospun EAPap was proportional to the applied voltage and larger than that of spincast EAPap. It is concluded that the performance of EAPap was improved by aligning cellulose fibers.

• ALGAE
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• 제20권4호
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• pp.325-331
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• 2005

Populations of Campylaephora borealis (Nakamura) Seo, Cho et Boo and C. crassa (Okamura) Nakamura show a year-around occurrence of all life-history stages. Such a concurrency of life-history stages produces problems in recognizing species in the field. Here, we invesitgated the morphological variation and life-history stages of both species using a statistical character analysis. Life-history stage was correlated with the seawater temperature in C. borealis, whereas it was dependant on biomass in C. crassa. Thalli had dichotomous branches with adaxial branchlets. The statistics showed that the seasonal change in morphology of C. borealis was significantly different from that of C. crassa in seven qualitative characters and five quantitative characters (p < 0.001), although six quantitative features including tetrasporangial size were similar in both species. The morphological difference between the two species may be due to the annual variation of branchlet number and the variance of branch subangle.

• 한국분말재료학회지
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• 제18권1호
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• pp.35-40
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• 2011

LAS-system ceramic powder, spodumene ($Li_2O{\cdot}Al_2O_3{\cdot}4SiO_2$), was successfully synthesized by a chemical solution technique employing PVA(polyvinyl alcohol) as an organic carrier. The PVA content affected the microstructure of porous precursor gels and the crystalline development. The optimum PVA content contributed to homogeneous distribution of metal ions in the precursor gel and it resulted in the synthesis of glass free $\beta$-spodumene powder having a specific surface area of $7.57\;m^2/g$. The agglomerated $\beta$-spodumene powders were also enough soft to grind to fine powders by a simple ball milling process. The microstructures of the densified powder compacts were strongly dependant on the minor phases of spodumene solid solution and amount of liquid phase, which were formed from the inhomogeneous precursors.

• 한국농공학회논문집
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• 제58권6호
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• pp.79-92
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• 2016

The objective of this study is to classify the types of rural areas (138 $si{\cdot}gun$) considering settlement environment by Decision Tree Method (CHAID). The CHAID method was used for decision tree algorithm and the seven dependant variables and 5 explanatory variables were selected, respectively. By decision tree method, rural areas were finally classified into six groups through three separate processes. City area, lower area in aging rate and higher area in farmland area ratio was analyzed to be relatively rich rather than other area in the case of settlement environment index. In the future, this study will be able to utilize as a reference to the planning of rural development projects.

• 환경생물
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• 제21권1호
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• pp.1-7
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• 2003

CYP1A 유전자는 cytochrome P450 약물대사효소에 속하며 다이옥신 등의 내분비계 장애물질에 의해 농도 의존적으로 유도되어 환경오염물질에 의해 유도되는 특성을 이용하여 환경오염물질에 대해 반응하는 생물체의 유전자 발현 변화뿐만 아니라 이를 토대로 특정지역의 환경오염에 관한 정보를 얻을 수 있다. 본 논문에서는 수서환경오염과 관련하여 CYP1A유전자의 유용성을 다각도로 논의하였다.

• 한국안전학회지
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• 제25권3호
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• pp.131-136
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• 2010

This study deals with the accident models of arterial link sections by vehicle type. The objectives are to analyze the characteristics of accidents, and to develop the models by type. In pursuing the above, this study uses the data of 414 accidents occurred on 24 major arterial links in 2007. The main results analyzed are as follows. First, the number of accidents is analyzed to account for about 47% in passenger car, 15% in SUV and 10% in trucks. Second, 3 Poisson regression models which are all statistically significant are developed using passenger car, SUV and truck as dependant variables. Finally, AADT and the number of traffic islands as common variables, and the number of pedestrian crossings, lanes, connecting roads, intersections(4-Leg), rate of medians and the number of bus stops as specific variables of the models are selected.

• Wind and Structures
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• 제5권2_3_4호
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• pp.379-392
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• 2002

Numerical flow computations around an aeroelastic 3D square cylinder immersed in the turbulent boundary layer are shown. Present computational code can be characterized by three numerical aspects which are 1) the method of artificial compressibility is adopted for the incompressible flow computations, 2) the domain decomposition technique is used to get better grid point distributions, and 3) to achieve the conservation law both in time and space when the flow is computed a with moving and transformed grid, the time derivatives of metrics are evaluated using the time-and-space volume. To provide time-dependant inflow boundary conditions satisfying prescribed time-averaged velocity profiles, a convenient way for generating inflow turbulence is proposed. The square cylinder is modeled as a 4-lumped-mass system and it vibrates with two-degree of freedom of heaving motion. Those blocks which surround the cylinder are deformed according to the cylinder's motion. Vigorous oscillations occur as the vortex shedding frequency approaches cylinder's natural frequencies.

• Journal of Pharmaceutical Investigation
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• 제11권3호
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• pp.14-20
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• 1981

One of the major objectives in the developments of a progesterone I.U.D. is to prepare devices which release drug at a constant rate for extended periods. A constant release rate is achived by maintaining drug concentration at a constant valve via the introduction of rate limiting membrane to solute diffusion at the surface of the devices. In this study, progesterone dispersed at monolithic device were prepared from polyhydroxy ethyl methacrylate. Constant release rate were obtained with device which were soaked in on ethanol-hexan solution. The release rate was dependant upon the concentration of the ethanolic solution in the soaking solution. This devices offer significant potential for futher development of hydrogel in the intrauterine contraception device for controlled release of progesterone.