• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 춘계학술발표대회 논문집
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• pp.131-134
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• 2000

Increased temperature adversely affects the reliability of a device. So, package material should have high thermal diffusion, i.e., high thermal conductivity. And, there are several other physical properties of polymeric materials that are important to microelectronics packaging, some of which are a low dielectric constant, a low coefficient of thermal expansion (CTE), and a high flexural strength. In this study, to get practical maximum packing fraction of AIN (granular type) filled EMC, the properties such as the spiral flow, thermal conductivity, CTE, and water resistance of AIN-filled EMC (65-vol%) were evaluated according to the size of AIN and the filler-size distribution. Also, physical properties of AIN filled EMC above 65-vol% were evaluated according to increasing AIN content at the point of maximum packing fraction (highly loading condition). The high loading conditions of EMC were set $D_L/D_S$=12 and $X_S$=0.25 like as filler of sphere shape and the AIN filled EMC in this conditions can be obtained satisfactory fluidity up to 70-vol%. As a result, the AIN filled EMC (70-vol%) at high loading condition showed improved thermal conductivity (about 6 W/m-K), dielectric constant (2.0~3.0), CTE(less than 14 ppm/$^{\circ}C$) and water resistance. So, the AIN filled EMC (70-vol%) at high loading condition meets the requirement fur advanced microelectronic packaging materials.

• Journal of Biosystems Engineering
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• 제35권5호
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• pp.310-315
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• 2010

The amount of salt intake of Korean people is 11.4 grams per a day, which is 2.3 times of the recommended daily salt intake by WHO - 5 grams of salt a day. The relationship between high salt consumption and increased risk of high blood pressure, observed not only in hypertensive but also in normotensive patients. High salt intake is also associated with an increased risk of heart attack, cerebral ischemia and osteoporosis. Therefore, this research is for developing a salt taste sensor to reduce sodium consumption and improve meal habits for the perception of a more bland taste of most foods. When the sensor was put into food sample, current intensity achieved with distribution cables. Current intensity was correlate with a simple equivalent of salt taste stimulus intensity. The salt taste sensor consists of salinity & temperature measuring probe, signal processing circuit and LCD display & LED warning light. When salinity is going over a set point, LCD displayer indicate salt taste on LCD panel by percent value (%), and at the same time, blue LED light change to red LED light. So we could know the grade of salt taste in soup before meals conveniently and objectively. The results show that operating range of 10 to $80^{\circ}C$ and accuracy of ${\pm}0.1%$ were achieved with an analysis time of about 2 or 3 sec. Moderate reductions in salt intake can help to avert adult diseases and lead a healthy life.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
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• pp.145-147
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• 2005

This paper presents a methodology for satisfying the thermal comfort of Indoor environment and reducing the summer peak demand power by minimizing the power consumption for an Air-conditioner within a space. KEPCO(Korea Electric Power Corporation) use the fixed duty cycle control method regardless of the indoor thermal environment. This method has disadvantages that energy saying depends on the set-point value of the Air-Conditioner and DLC has no net effects on Air-conditioners if the appliance has a lower operating cycle than the fixed duty cycle. A variable duty cycle estimates the PMV(Predict Mean Vote) at the next step with a predicted temperature and humidity coming from the back propagation neural network model. It is possible to reduce the energy consumption by maintaining the Air-conditioner's OFF state when the PMV lies in the thermal comfort range. The proposed methodology uses the historical real data of Sep. 7th, 2001 from a classroom in seoul to verify the effectiveness of the variable duty cycle method comparing with fixed duty cycle. The result shows that the variable duty cycle reduces the peak demand to 2.6times more than fixed duty cycle and increases the load control ratio by 8% more. Based on the variable duty cycle control algorithm, the effectiveness of DLC is much more improved as compared with the fixed duty cycle.

• 대한전자공학회논문지
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• 제26권2호
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• pp.18-28
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• 1989

본 논문에서는 설치후 초기단계에 있는 우주전파 관측용 13.7m 안테나의 지향정도 확립과 효율측정에 대하여 기술하였다. 지향성 모델은 처음 단계인 모델 1, 2에서는 태양과 달 같은 시직경이 크고 전파강도가 센 천체를 관측하여 설정되었고, 이를 이용한 모델 3, 4에서 전 하늘에 걸친 SiO 메이저원인점 전파원을 관측하여 방위각 오차 3.8" 고도각 오차 10.5"의 실용성 있는 번위로 확립되었다. 구경은 86GHz대에서 각각 35%, 50%로 나타났다.

• 벤처창업연구
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• 제10권6호
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• pp.253-260
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• 2015

본 연구에서는 화재 시뮬레이션인 FDS와 피난 시뮬레이션인 Pathfinder를 이용하여 건물의 중앙제어실을 화재발생 지점으로 설정하여 화재안전성 평가 연구를 수행하였다. 먼저 화재시뮬레이션을 이용하여 시간의 경과에 따른 가시거리 분포, 온도분포, CO의 농도분포 등의 정량적 결과를 도출 하였으며, 이 결과를 토대로 피난시뮬레이션을 실시하여 재실자들의 피난시간을 계산함으로써 최종적인 피난안전성 평가 결과를 도출하였다. 화재 시뮬레이션 결과 가시거리의 분포에 따라 위험도가 증가하기 때문에 이 값을 이용하여 피난시뮬레이션을 실시하였으며 그 결과 최종적으로 127.9초에 모든 인원이 대피하는 결과를 얻을 수 있었다. 수치해석 결과 건물 내 모든 장소에서 피난 소요시간이 피난 허용시간을 초과하지 않는 것으로 분석됨에 따라 대피자의 안전성이 확보되는 것으로 분석되었다. 이러한 안전성 평가의 결과는 최악의 조건인 소방설비의 미작동에 근거한 종합안전성평가로서 실제 화재 발생 시 소방설비와 연계한다면 보다 우수한 피난안전성능이 확보될 것으로 평가할 수 있다.

• Parasites, Hosts and Diseases
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• 제52권3호
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• pp.263-271
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• 2014

PCR detection of intestinal protozoa is often restrained by a poor DNA recovery or by inhibitors present in feces. The need for an extraction protocol that can overcome these obstacles is therefore clear. $QIAamp^{(R)}$ DNA Stool Mini Kit (Qiagen) was evaluated for its ability to recover DNA from oocysts/cysts directly from feces. Twenty-five Giardia-positive, 15 Cryptosporidium-positive, 15 Entamoeba histolytica-positive, and 45 protozoa-free samples were processed as control by microscopy and immunoassay tests. DNA extracts were amplified using 3 sets of published primers. Following the manufacturer's protocol, the kit showed sensitivity and specificity of 100% towards Giardia and Entamoeba. However, for Cryptosporidium, the sensitivity and specificity were 60% (9/15) and 100%, respectively. A series of optimization experiments involving various steps of the kit's protocol were conducted using Cryptosporidium-positive samples. The best DNA recoveries were gained by raising the lysis temperature to the boiling point for 10 min and the incubation time of the InhibitEX tablet to 5 min. Also, using a pre-cooled ethanol for nucleic acid precipitation and small elution volume ($50-100{\mu}l$) were valuable. The sensitivity of the amended protocol to Cryptosporidium was raised to 100%. Cryptosporidium DNA was successfully amplified by either the first or the second primer set. When applied on parasite-free feces spiked with variable oocysts/cysts counts, ${\approx}2$ oocysts/cysts were theoretically enough for detection by PCR. To conclude, the Qiagen kit with the amended protocol was proved to be suitable for protozoan DNA extraction directly from feces and support PCR diagnosis.

• Nuclear Engineering and Technology
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• 제14권4호
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• pp.196-203
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• 1982

본 논문에서는 고리 1호기의 기사용 핵연료 집합체를 수송하기 위한 Cask를 설계하였다. 이를 위하여 고리 1호기의 기사용 핵연료 집합체로부터 방출되는 감마선과 중성자를 계산하여 MORSE 및 ANISN전산 코드로써 차폐 계산을 수행하였다. 그 결과, 9개의 집합체를 동시에 수송할 수 있는 Steel Cask가 가장 적합하다는 것을 밝혔다. 이 Steel Cask에 대한 안전성을 평가하기 위하여 연료봉의 중심 온도와 복재온도를 계산하여 핵연료의 용융점보다 훨씬 낮음을 증명하였다. 또한 KENO와 MORSE전산 코드를 사용하여 임계도 계산을 수행하여 미임계 상태임을 증명하였다. 이로써 9개의 기사용 핵연료 집합체를 동시에 수송할 수 있는 Steel Cask를 간단히 설계하였다.

• 설비공학논문집
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• 제8권3호
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• pp.437-450
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• 1996

A set of stability equations is formulated for natural convection flows adjacent to a vertical isothermal surface melting in cold pure water. It takes account of the nonparallelism of the base flows. The melting rate is regarded as a blowing velocity at the ice surface. The numerical solutions of the linear stability equations which constitute a two-point boundary value problem are accurately obtained for various values of the density extremum parameter $R=(T_m-T_{\infty})/(T_0-T_{\infty})$ in the range $0.3{\leq}R{\leq}0.6$, by using a computer code COLNEW. The blowing effects on the base flow becomes more significant as ambient temperature ($T_{\infty}$) increases to $T_{\infty}=10^{\circ}C$. The maximum decrease of heat transfer rate is about 6.4 percent. The stability results show that the melting at surface causes the critical Grashof number $G^*$ and the maximum frequency of disturbances to decrease. In comparision with the results for the conventional parallel flow model, the nonparallel flow model has a higher critical Grashof number but has lower amplification rates of disturbances than does the parallel flow model. The spatial amplification contours exhibit that the selective frequency $B_0$ of the nonparallel flow model is higher than that of the parallel flow model and that the effects of melting are rather small. The present study also indicates that the selective frequency $B_0$ can be easily predicted by the value of the frequency parameter $B^*$ at $G^*$, which comes from the neutral stability results of the nonparallel flow model.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.62-67
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• 2009

This paper describes the characteristics of scroll type stirling engine receiver. Scroll type stirling engine operated scroll compressor and expander instead of piston. Pass dimension of the receiver was $14(W){\times}14(H)$ mm and total pass length was 5,049 mm. External dimension of the receiver was $300{\times}300mm$. The experimental facility consisted of parabolic dish concentrator, compressor to supply air, triplex air filter, and flowmeter. In this study, basic experimental conditions were set at a inlet pressure of 5 bar and volume flow rate of $25m^3/hr$. As a result, air temperature in receiver at each measuring position of point 1, 2, 3 were $241^{\circ}C$, $465^{\circ}C$, and $542^{\circ}C$ respectively at inlet pressure of 5.5 bar and volume flow rate of $24.6m^3/hr$. As DNI increasing, heat transfer coefficient of the receiver changed from $695W/m^2K$ to $827W/m^2K$. Average heat transfer coefficient of receiver in the experiment was $798W/m^2K$. In addition, receiver efficiency became about 83%.

• 한국산학기술학회논문지
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• 제13권8호
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• pp.3307-3314
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• 2012

농어촌 주택 표준모델에 대한 연간 건물에너지요구량을 DesignBuilder를 사용하여 계산하였다. 실내설정온도, 외벽의 열관류율, 창호타입, 환기량을 변화시키며 건물의 설계/운영 변수들이 에너지요구량에 미치는 영향을 분석하였다. 건물의 크기와 상관없이 난방에너지요구량이 냉방에너지요구량보다 더 큰 것으로 나타났다. 단열재 두께를 증가시켜 외벽의 열관류율을 감소시키면 단열효과의 증가로 난방에너지요구량은 감소하지만 냉방에너지요구량이 증가한다. 하지만 외벽의 열관류율 조절을 통한 난방에너지요구량의 절감에는 한계가 있으므로 외부에 직접 노출된 외벽의 면적을 최소화하는 것이 더 효과적인 것으로 판단된다. 계산에 사용된 4가지 창호 중 일반 이중창호가 난방에너지요구량 측면에서 가장 유리한 것으로 나타났다. 침기량은 일정하게 유지하고 단위시간당 환기량을 증가시킨 경우 냉방에너지요구량은 큰 변화가 없었으나 난방에너지요구량이 증가하였다. 실내의 공기질이 만족되는 범위 내에서 환기량을 최소화하는 것이 연간 건물에너지요구량을 줄이는데 유리한 것으로 판단된다.