• Journal of Biosystems Engineering
• /
• 제24권1호
• /
• pp.9-18
• /
• 1999

This study was performed to investigate the optimum microalgal culture conditions using flask culture and to find the feasibility of using the flue gas of the rice husk incinerator for cultivating the microalgae. The optimum initial pH of media was 4.5 for the microalgae culture, and the intermittently illuminated culture was more effective than the continuous illuminated culture. Thus, the balance between photosynthesis and formative metabolism must be considered thoroughly to cultivate microalgal cells. The optimum CO2 concentrations were in the range of 7 to 10%, and the optimum temperature was about 35$^{\circ}C$ in both the daytime and the nighttime for the culture. When flue gas of the rice husk incinerator was applied to the microalgae culture using stirred photobioreactor, the dry cell weight was 0.026 g dry biomass/hr$.$l. The results obtained in experiments indicated that the flue gas was effective for microalgae culture without any limitations.

• 한국식품영양과학회지
• /
• 제27권1호
• /
• pp.102-108
• /
• 1998

This study was performed to establish manufacturing of garlic vinegar which has medical action component of garlic and functionality of vinegar. Optimum alcohol concentration, and garlic juice concentration for the mpnufacturing of garlic vinegar were 5%, 10%, respectively, and the optimum conditions were obtained when the fermentation was carried out at agitation of agitation of 120rpm and temperature of 3$0^{\circ}C$. The acetic acid content of optimum condition was 4.87% and thiosulfinate content was 37.5mg after 20days fermentation. The major organic acid compositions in garlic vinegar were oxalic acid, citric acid, malic acid and acetic acid, and free amino acid compositions were aspartic acid, threonine, serine, glutamic acid, alanine etc.

• 한국포장학회지
• /
• 제6권1호
• /
• pp.1-11
• /
• 2000

In optimum design of packaging container for bulk materials, minimum board area, compression performance and distribution efficiency must be considered. In this study, mathematical models for minimum board area (RMA), compression strength (CS) and maximum compression strength per unit board area (MCSA) of container as algorithm for optimum design of packaging conatiner for bulk materials were developed as follows : RMA=f(V,D), ${\alpha}_{RMA}=f(V,D)$, MCSA=f(V,D), and ${\alpha}_{MCSA}=f(V,D)$. In order to develop these models, compression test according to various dimensions of container and response surface analysis for minimum board area, compression strength, and maximum compression strength per unit board area of container were carried out. In developed models, volume and depth of container were principal independent variables. Through the verified results for these models, optimum design of packaging container on the design conditions and limit conditions was possible. These models might be used in developing optimum design software of packaging container for bulk materials.

• 한국컴퓨터정보학회논문지
• /
• 제16권5호
• /
• pp.101-107
• /
• 2011

본 논문에서는 적응 배열 안테나 시스템에서 간섭 및 재밍 신호를 제거하기 위해서 최적 가중 벡터를 연구하였다. 최적 가중 벡터는 선형 제한 조건에서 최소 분산 알고리즘과 비용함수를 적용시켜 구하였고, 목표물의 신호를 정확히 추정하였다. 적응 배열 안테나 시스템은 간섭 및 재머전력을 감소시키고 신호대 잡음비를 향상시키는 시스템이다. 적응 배열 안테나 시스템은 각 안테나 배열 소자의 출력이 탭(Tap)을 거쳐 지연되고 각 탭에 복소 가중치가 곱해져서 최종적으로 하나의 복합신호를 만든다. 최적의 가중치를 구하기 위해서 본 논문에서는 입력 공분산 행렬의 최적 가중벡터를 이용하였다. 본 논문에서 제안된 알고리즘으로 모의 실험한 결과 분해능은 $3^{\circ}$이하로 향상되었으며 부엽은 약 10 dB 감소하였음을 입증하였다.

• 한국레이저가공학회지
• /
• 제7권2호
• /
• pp.1-10
• /
• 2004

This work was attempted to join SCP sheet and STS304 sheet by using Nd:YAC laser beam. SCP sheet has good formability and low cost, while STS304 has excellent corrosion resistance and mechanical properties in high temp. In this experiment, butt joint type was used to develop the tailored blank welding for dissimilar steel. Sheets which have different thermal properties. Computer simulation was conducted to obtain the off-set position for efficient welding by considering laser power, scanning speed, focal length and basic properties. The result showed that the optimum thermal distribution was obtained when the laser beam was irradiated at $0.05{\sim}0.1$ mm off-set toward the SCP sheet side. The experiment was conducted based on the result of computer simulation to show the same optimum conditions. Optimum conditions were 3KW in laser beam power, 6m/min in scanning speed, -0.5mm in focal position, 0.1mm off-set toward SCP. Microhardness test, tensile test, bulge test, optical microscopy, EDS, and XRD were performed to observe the microstructure around fusion zone and to evaluate the mechanical properties of optimum conditions, The weld zone had high microhardness values by the formation of the martensitic structure. Tensile test measured the strength of welded region by vertical to strain direction and the elongation of welded region by parallel to strain direction. Bulge test showed $52\%$ formability of the original materials. Bead shape, grain size, and martensitic structure were observed by the optical microscopy in the weld zone. Detailed results of EDS, XRD confirmed that the welded region was connected of martensitic structure.

• Applied Biological Chemistry
• /
• 제48권1호
• /
• pp.89-92
• /
• 2005

삼백초 지상부의 추출조건을 설정하고자 추출용매 및 시간에 따른 이화학적 특성을 살펴보았다. 추출용매 조건은 40% 에탄올을 사용하여 추출할 때로 나타났으며, 이때, 총수율, 전자공여능, 총페놀함량, 총플라보노이드 함량은 각각 13.50%, 83.50%, 2.60 mg/ml 및 2.09 mg/ml으로 나타났다. 최적의 추출 시간은 4시간으로 나타났으며, 이때, 총수율, 전자공여능,총폐놀함량, 총플라보노이드 함량은 각각 12.79%, 71.13%, 2.83 mg/ml 및 2.16 mg/ml으로 나타났다. 삼백초 지상부를 40% 에탄을 추출물로 4시간 추출하였을때, quercetin 함량은 360.13 mg/100 g으로 나타났으며, quercetin 함량은 1379.54 mg/100 g으로 나타났다. 삼백초 지상부를 이용하여 추출조건을 설정한 결과 40% 에탄올을 이용하여 4시간 추출하는 것이 가장 적합한 것으로 나타났다.

• 한국식생활문화학회지
• /
• 제9권1호
• /
• pp.87-93
• /
• 1994

This study was conducted to present a method that determine the optimum conditions for the preparation of chinese whole cabbage kimchi. After Sensory and chemical characteristics of kimchi with various salt concentration in brine, brining time and storage period at equal saltiness were measured, the optimum conditions for the preparation of chinese whole cabbage kimchi were determined with the use of the response surface methodology. The results are summarized as follows; 1. The more salt concentration in brine, the longer brining time and storage period, resulted in the lower pH and the higher titratable acidity of kimchis. As the salt concentration in brine and brining time increased, kimchi reaches at optimum titratable acidity of it within a shorter time. 2. As the salt concentration in brine and brining time increased, content of succinic acid decreased but that of lactic, acetic, and propionic acid increased. Amount of citric, malic and succinic acid decreased but that of lactic, acetic acid increased, with storage day. 3. Sensory data showed that firmness and green cabbage flavor of kimchi decreased while toughness, carbonic mouthfeel, sourness and staled flavor increased with increased salt concentration in brine, brining time and storage day. As the storage period increased, crispness of kimchi decreased. 4. The optimum conditions for the preparation of chinese whole cabbage kimchi were as follows: Optimum salt concentration in brine, brining time, and storage period were 19.5%, 3 hours and 45 minutes, and 12 hours.

• 대한기계학회논문집
• /
• 제16권12호
• /
• pp.2358-2367
• /
• 1992

본 연구에서는 그 기초단계로서 작동유체의 실제상태변화에 근접하면서 간편 한 근사적인 단열해석법을 적용하여 VM사이클의 구체적인 예비설계조건을 제시하고자 한다.

• 한국세라믹학회지
• /
• 제34권5호
• /
• pp.473-482
• /
• 1997

Titanium carbide(TiC) has a poor sinterability due to the strong covalent bond. Thus, it is generally fabricated by either hot pressing or pressureless-sintering at elevated temperature by the addition of sintering aids such as nickel(Ni), molybdenum(Mo) and cobalt(Co). However, these sintering methods have the following disadvantages; (1) the complicated process, (2) the high energy consumption, and (3) the possibility of leaving inevitable impurities in the product, etc. In order to reduce above disadvantages, we investigated the optimum conditions under which dense titanium carbide bodies could be synthesized and sintered simultaneously by high pressure self-combustion sintering(HPCS) method. This method makes good use of the explosive high energy from spontaneous exothermic reaction between titanium and carbon. The optimum conditions for the nearly full-densification were as follows; (1) The densification of sintered body becomes high by increasing the pressing pressure from 400kgf/$\textrm{cm}^2$ upto 1200 kgf/$\textrm{cm}^2$. (2) Instead of adding the coarse graphite or activated carbon, the fine particles of carbon black should be added as a carbon source. (3) The optimum molar ratio of carbon to titanium (C/Ti) was unity. In reality, titanium carbide body which were prepared under optimum conditions had relatively dense textures with the apparent porosity of 0.5% and the relative density of 98%.

• 한국소음진동공학회논문집
• /
• 제16권7호
• /
• pp.690-696
• /
• 2006

Thickness of damping layer in sandwich plate needs to be optimized in order to make modal loss factor of the sandwich plate maximum. Since previous studies were interested in noise reductions over high frequency range, the modal properties were derived based on simply supported boundaries. This conventional formula is approximately applicable to other boundary conditions over high frequency range only. The purpose of this study is to propose a method to determine optimum damping layer thickness of sandwich plate for maximum modal damping in low frequency range when the boundary condition is not a simple support. The conventional RKU equation based on simply supported boundary is modified to reflect other boundary conditions and the modified RKU equation is subsequently applied to determine the optimum damping layer thickness for arbitrary conditions. In order to reflect frequency-dependent characteristics of elastic modulus of the damping layer, an iteration method is proposed in determining the modal properties. Test results on sandwich plates for optimum damping layer thickness are compared with predictions by the proposed method and conventional method.