• 설비공학논문집
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• 제11권1호
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• pp.10-17
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• 1999

The present work presents condensation heat transfer and pressure drop data for the flow of R-12 in flat extruded aluminum tubes with small hydraulic diameters. The tube outside dimensions are $18mm(width){\times}1.7mm(height)$. Three types of internal geometry with the same outside dimensions are tested : sample 1 (7 tube holes), sample 2 (13 tube holes) and sample 3 (7 tube holes, micro-fin). The overall heat transfer coefficient is obtained for air-to-refrigerant heat transfer, and the Wilson plot method is used to determine the heat transfer coefficient for refrigerant flow. The sample 2 and sample 3 show significantly higher performance than sample 1. The heat transfer rates for the sample 2 and sample 3 are 9% and 12% higher, respectively, than sample 1. The friction factors for the sample 2 and sample 3 are 11.9% and 2.4% higher, respectively, than sample 1.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2666-2671
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• 2007

This work presents microchannel heat sink shape optimization procedure using Kriging method. Design variables relating to microchannel width, depth and fin width are selected, and thermal resistance has been taken as objective function. Design points are selected through a three-level fractional factorial design of sampling method. Navier-Stokes and energy equations for laminar flow and conjugate heat transfer are solved at these design points using a finite volume solver. Solutions are carefully validated with experimental results. Using the numerically evaluated objective function, a surrogate model (Kriging) is constructed and optimum point is searched by sequential quadratic programming. The process of shape optimization greatly improves the thermal performance of microchannel heat sink under constant pumping power.

• 대한기계학회논문집B
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• 제31권9호
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• pp.733-740
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• 2007

Microchannel heat sink shape optimization is performed using Kriging method. Design variables relating to microchannel width, depth and fin width are selected, and thermal resistance has been taken as objective function. Design points are selected through a three-level fractional factorial design of sampling method. Navier-Stokes and energy equations for laminar flow and conjugate heat transfer are solved at these design points using a finite volume solver. Solutions are carefully validated with experimental results. Using the numerically evaluated objective function, a surrogate model (Kriging) is constructed and optimum point is searched by sequential quadratic programming. The process of shape optimization greatly improves the thermal performance of microchannel heat sink under constant pumping power.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.107.1-107.1
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• 2014

We have developed and commercialize a time-of-flight - medium energy ion scattering spectrometry (TOF-MEIS) system (model MEIS-K120). MEIS-K120 adapted a large solid acceptance angle detector that results in high collection efficiency, minimized ion beam damage while maintaining a similar energy resolution. In addition, TOF analyzer regards neutrals same to ions which removes the ion neutralization problems in absolute quantitative analysis. A TOF-MEIS system achieves $7{\times}10^{-3}$ energy resolution by utilizing a pulsed ion beam with a pulse width 350 ps and a TOF delay-line-detector with a time resolution of about 85 ps. TOF-MEIS spectra were obtained using 100 keV $He^+$ ions with an ion beam diameter of $10{\mu}m$ with ion dose $1{\times}10^{16}$ in ordinary experimental condition. Among TOF-MEIS applications, we report the quantitative compositional profiling of 3~5 nm CdSe/ZnS QDs, As depth profile and substitutional As ratio of As implanted/annealed Si, Ionic Critical Dimension (CD) for FinFET, Direct Recoil (DR) analysis of hydrogen in diamond like carbon (DLC) and InxGayZnzOn on glass substrate.

• 환경생물
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• 제38권1호
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• pp.106-113
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• 2020

This study identified the differences in the morphometric characteristics of the truss and classical dimensions between diploid and triploid Far Eastern catfish, Silurus asotus, and provided methods for sorting diploid and triploid Far Eastern catfish based on morphometric observations. The significant variables were the direct distance between the anterior edge of the lower lip and the anterior insertion of the dorsal fin(DALAD), the horizontal distance between the anterior edge of the lower lip and the anterior insertion of the ventral fin (HALAV), the direct distance between the anterior edge of the upper lip and the first nostril(DAUF), the direct distance between the anterior edge of the upper lip and the second nostril(DAUS), the interorbital width(IW), and the mandible barbel length (ManBL). The more significant variables were HALAV, DALAD, DAUF, IW, and DAUS. The most useful combination of variables for separating the two groups was DALAD, IW, and DAUF, which correctly classified 85% of the catfish as triploid or diploid, and that percentage was the maximum degree of value possible (p<0.05). Triploid Far Eastern catfish had a high rate of growth in the head region and body depth during the first year after hatching. Triploid Far Eastern catfish had smaller heads and shorter mandible barbels than diploid Far Eastern catfish.

• International Journal of Air-Conditioning and Refrigeration
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• 제13권2호
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• pp.71-82
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• 2005

The shape of $7\times7$ pin-fins heat sink is optimized numerically to obtain the minimum pressure drop and thermal resistance. In this study, the fin height (h), fin width (w), and fan-to-heat sink distance (c) are chosen as the design variables and the pressure drop $({\Delta}P)$ and thermal resistance $(\theta_j)$ are adopted as the objective functions. To obtain the optimum design values, we used the finite volume method for calculating the objective functions, the BFGS method for solving the unconstrained non-linear optimization problem, and the weighting method for predicting the multi-objective problem. The results show that the optimum design variables for the weighting coefficient of 0.5 are as follows: W=4.653 mm, h=59.215mm, and c=2.667mm. The objective functions corresponding to the optimal design are calculated as ${\Delta}P=6.82$ Pa and $(\theta_j)=0.56K/W$. The Pareto solutions are also presented for various weighting coefficients and they will offer very useful data to design the pin-fins heat sink.

• 한국수산과학회지
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• 제53권6호
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• pp.960-964
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• 2020

For the first time, a single specimen (68.47 mm in total length) of Lumpenopsis pavlenkoi Soldatov, 1916 belonging to the family Stichaeidae was collected from the northernmost area of the eastern coast of Korea (Gosung, Gangwon Province) in April, 2020, using square net (1.0 m width, 0.3 m height, 2.0 mm mesh size). This species is characterized by elongated and compressed body, absence of lateral line and cirri on head, presence of scales on cheek, dorsal fin with only 50 spines, anal fin with 2 spines and 30 soft rays, and separated operculum and isthmus. The body is yellowish with 7 saddles. The new Korean name "Kko-ma-be-do-ra-chi-sog" is proposed for the genus Lumpenopsis, and "Deung-jeom-kko-ma-be-do-ra-chi" is proposed for the species L. pavlenkoi.

• 한국어류학회지
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• 제5권1호
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• pp.85-95
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• 1993

1990년 성숙한 연어의 성별 형태학적 특징을 조사하였다. 성숙한 수컷은 연장되고 휘어진 턱을 가지고 있으며 턱 위에 강한 이빨을 가지고 있다. 두장에 대한 주둥이의 길이와 위턱은 수컷이 암컷보다 크고 반면 두장에 대한 안경과 뺨은 수컷이 암컷보다 작았다. 표준체장(PBL)에 대한 체고, 미병고, 등지느러미, 기름지느러미 길이는 모두 수컷이 컸다. 각 지느러미 줄기수, 새파수와 유문수의 수는 암수 차이가 없었으나 측선비늘수와 미추골수는 암컷이 수컷보다 많았다. 두개골 중 인설골과 서골의 형태는 암수 차이가 인정되지 않았지만 상사골의 길이에 대한 폭의 비값은 수컷이 암컷보다 크고 부설골의 앞 뒤돌기 비값은 암컷이 수컷보다 컸다.

• 디지털융복합연구
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• 제19권8호
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• pp.43-48
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• 2021

우리나라 가자미는 총 26종으로 알려져 있고 어종에 대한 형태로 분류한 연구는 많이 진행되었으나 육안으로 구분하기에 어려움이 있으며 가자미와 도다리 등으로 혼용, 오용되어 쓴다. 이 연구는 도다리와 흘림도다리의 분류학적 기준을 제시하고 수산자원을 활용한 관광교육 자료로 활용하고자 한다. 계수와 계측을 통하여 형태적 비교를 하였고 두 어종은 전체적으로 체고는 낮고 체폭이 넓은 타원형으로 납작하게 측편되어 있으며 뒷지느러미는 등지느러미와 비슷한 형태와 크기로 발달하였고 꼬리지느러미는 부채꼴 모양으로 넓게 펼쳐져 있었다. 설골 중 미설골의 주부, 좌골부, 분문돌기의 세 부분에서 좌골부와 부문돌기에서 굽어진 정도, 벌어진 각도, 모양의 차이를 보여 대표적인 분류형질에 부합하였다. 또한 가자미과 어류의 한 속으로서 형질을 구분하여 분류하고 그 특징을 정리하며 추후 학명과 명칭의 오용을 줄이는 수산해양 교육 자료로서 기초가 되기를 희망한다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권2호
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• pp.192-198
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• 2017

In this paper, we propose a novel double gate vertical channel tunneling field effect transistor (DVTFET) with a dielectric sidewall and optimization characteristics. The dielectric sidewall is applied to the gate region to reduced ambipolar voltage ($V_{amb}$) and double gate structure is applied to improve on-current ($I_{ON}$) and subthreshold swing (SS). We discussed the fin width ($W_S$), body doping concentration, sidewall width ($W_{side}$), drain and gate underlap distance ($X_d$), source doping distance ($X_S$) and pocket doping length ($X_P$) of DVTFET. Each of device performance is investigated with various device parameter variations. To maximize device performance, we apply the optimum values obtained in the above discussion of a optimization simulation. The optimum results are steep SS of 32.6 mV/dec, high $I_{ON}$ of $1.2{\times}10^{-3}A/{\mu}m$ and low $V_{amb}$ of -2.0 V.