• 대한전자공학회논문지TC
• /
• 제37권11호
• /
• pp.23-31
• /
• 2000

평면형 구조에서 공간영역 그린함수를 구하기 위해서는 무한 Sommerfeld 적분을 계산하여야 한다. 무한 적분을 짧은 시간에 계산하기 위한 복소 영상법(complex image method)과 2단계 근사화법(two-level method)은 전원점과 관측점 사이의 거리가 가까운 경우에는 정확하지만, 거리가 멀어지면 오차가 커지게 된 다. 본 논문에서는 실수축 상의 적분경로에서 파수영역 그린함수를 근사화 함으로써 코플래너 도파로 구조에서 기존의 결과에 비해 정확한 closed-form 그린함수를 구하는 방법을 제시하였다.

• 한국가시화정보학회지
• /
• 제20권2호
• /
• pp.78-85
• /
• 2022

In these days, the rapid development in prediction technology using artificial intelligent is being applied in a variety of engineering fields. Especially, dimensionality reduction technologies such as autoencoder and convolutional neural network have enabled the classification and regression of high-dimensional data. In particular, pixel level prediction technology enables semantic segmentation (fine-grained classification), or physical value prediction for each pixel such as depth or surface normal estimation. In this study, the pressure distribution of the ship's surface was estimated at the pixel level based on the artificial neural network. First, a potential flow analysis was performed on the hull form data generated by transforming the baseline hull form data to construct 429 datasets for learning. Thereafter, a neural network with a U-shape structure was configured to learn the pressure value at the node position of the pretreated hull form. As a result, for the hull form included in training set, it was confirmed that the neural network can make a good prediction for pressure distribution. But in case of container ship, which is not included and have different characteristics, the network couldn't give a reasonable result.

• 공업화학
• /
• 제1권1호
• /
• pp.23-29
• /
• 1990

급속동결 전처리가 유기이온교환 수지의 분쇄에 미치는 효과를 연구하였다. 습윤상태의 이온교환 수지를 고체탄산 또는 액체질소를 이용하여 급속동결하면 이온교환 수지의 내부구조가 물리적으로 파괴되며 일단 파괴된 수지는 다시 실온이 되어도 원래의 상태로 회복되지 않음을 발견하였다. 따라서 급속동결한 수지는 실온에서도 분쇄가 매우 용이하며 이 효과는 양이온교환 수지가 음이온교환 수지에 비하여 더 크게 나타났다. 아울러 음이온교환 수지의 경우, 급속동결 전처리 효과 뿐만 아니라 이온종류 역시 분쇄에 큰 영향을 미침을 관찰할 수 있었다.

• 한국공간구조학회논문집
• /
• 제11권4호
• /
• pp.89-99
• /
• 2011

최근 테러의 대상 범위는 보다 광범위해 지고 있으며, 국내의 테러발생위험이 지속적으로 증가하고 있는 가운데 테러의 형태는 국가의 중요시설과 같은 경성표적(Hard Target)에서 초고층건물과 같은 다중이용시설의 연성표적(Soft Target)으로 변화하고 있다. 따라서 본 논문에서는 Fema 455 - Rapid Visual Screening을 통해 국내의 초고층건물과 고층건물의 테러위험도 평가결과를 국내의 저층건물의 테러위험도 평가결과와 비교하여 초고층건물의 테러위험도를 분석하였다. 그 결과 초고층건물 및 고층건물은 저층건물에 비해 Consequences, Vulnerability Rating보다 Threat Rating항목이 상대적으로 높았으며, 이는 초고층건물의 거주인원 및 국가적 또는 지역적인 상징성 및 가시성 부분에서 테러위험도가 높은 것이 주요 원인으로 분석되었다.

• 한국주조공학회지
• /
• 제22권5호
• /
• pp.265-270
• /
• 2002

A novel jewelry master pattern manufacturing process which reduce manufacturing steps by employing a Duraform rapid prototyping mold and a low melting alloy has been suggested. The novel process follows the steps of 'jewelry 3D CAD design ${\rightarrow}$ Durafrom RP mold ${\rightarrow}$ low melting alloy master pattern' while the previous process follows more complicated steps of 'jewelry idea sketch ${\rightarrow}$ detailed drawing ${\rightarrow}$ wax carving ${\rightarrow}$ flask ${\rightarrow}$ silver master pattern.' An upper and a lower part of molds have been manufactured of Duraform powder, of which melting point is $190^{\circ}C$. A maser pattern was manufactured by pouring a low melting alloy of Pb-Sn-Bi-Cd, so called Woods Metal, of which melting point is $70^{\circ}C$, into the mold. The master pattern is a shape of a disk of 20mm diameter that contains various design factors. The variations of dimensions, surface roughness, surface pore ratio were measured by an optical microscope, a surface roughness profilometer, and a Rockwell hardness tester. The pattern made of were maeasured by an optical microscope, a surface roughness profilometer, and a Rockwell hardness tester. The pattern made of low melting alloy has sufficient surface hardness, and surface pore ratio to be used as the jewelry master pattern.

• Journal of Microbiology and Biotechnology
• /
• 제12권3호
• /
• pp.522-525
• /
• 2002

A very rapid and efficient separation technique for cellular rhizobial cyclosophoraoses was developed based on fractional precipitation and partition chromatography. Cyclosophoraoses are known to function in the osmotic regulation and root nodule formation of legumes during the nitrogen fixation process. Cyclosophoraoses are produced as unbranched cyclic (1longrightarrow12)-${\beta}$-D-glucans in Agrobacterium or Rhizobium species. Recent research has shown that cyclosophoraoses can form inclusion complexation with various unstable or insoluble guest chemicals, thereby implying great potential for industrial application. Typical separation of pure cellular cyclosophoraoses has been so far carried out by several time-consuming steps, including size exclusion, anion exchange, and desalting liquid chromatographies, with a relatively poor recovery. However, the proposed method demonstrated that the successive application of fractional ethanol precipitation and one step of silica gel-based flash column chromatography was enough to simultaneously purify neutral or anionic forms of cyclosophoraoses. This novel technique is very rapid and provides a high recovery.

• 한국분말재료학회지
• /
• 제10권1호
• /
• pp.15-20
• /
• 2003

Hybrid $A1_2O_3-TiC$ ceramic particle reinforced 6061 and 5083 Al composite powders were prepared by the combination of twin rolling and stone mill crushing process, followed by consolidating processes of cold compaction, degassing and hot extrusion. The composite bar consists of lamellar structure of ceramic particle rich area and matrix area, in which the hybrid was decomposed into each TiC of about $3-4\mutextrm{m}$ and $AI_2O_3$ particles of about $1-2\mutextrm{m}$ in diameter. It also found that fine $Mg_2Si$ precipitates of about 30 nm were embedded in the matrix, which have grains of about 3 $\mutextrm{m}$. Higher UTS was measured at the 5083 composite bar compared to the conventionally fabricated composite, due to again refinement effect by the rapid solidification. No particle was shown to form in the interface between the matrix and reinforcement, whereas carbon was diffused into the matrix.

• 환경영향평가
• /
• 제11권3호
• /
• pp.223-230
• /
• 2002

The rapid impact assessment matrix (RIAM) might be a new tool for performance of an environmental impact assessment (EIA), comparing with many traditional methods of EIA, which have produced large reports setting out the subjective judgement reached by the assessors. The main criticisms of E1A are in part a natural result of the traditional method used. RIAM uses a structured matrix to allow for such judgement, both subjective and those based on quantitative data, to be made on a like-by-like basis, and provided a transparent and permanent record of the judgement made. Also, the computerized RIAM system using software program allows for the matrix to be shown in graphical form, which greatly enhances the clarity of the results produced by this method. RIAM provides a system by which development options and scenarios can be rapidly evaluated. To illustrate the use of RIAM, an example from an EIA study using application of scoping by assessment criteria in Environmental Impact Regulation of Korea was given. The criteria that might be used to evaluation EIA methods, and how RIAM measures up against these criteria, are discussed.

• 한국전기전자재료학회논문지
• /
• 제26권5호
• /
• pp.410-414
• /
• 2013

Rapid thermal processing (RTP) abruptly decreases the time required to perform solar cell processes. RTP were used to form emitter of crystalline silicon solar cells. The emitter sheet resistance is studied as a function of time and temperature. The objective of this study is reduction of doping process time with same performance. Emitter difRapid thermal dfusion was carried out by using a spin on doping and a RTP. iffusion was performed in the temperature range of $700{\sim}750^{\circ}C$ for 1m 30s~15 m. Thermal budgets yielded a $50{\Omega}/sq$ emitter using a P509 source. To reduce process time and get high efficiency, rapid thermal diffusion by IR lamp was employed in air atmosphere at $700^{\circ}C$ for 15 m.

• Journal of Biosystems Engineering
• /
• 제34권4호
• /
• pp.254-259
• /
• 2009

Conventional methods for pathogen detection and identification are labor-intensive and take several days to complete. Recently developed biosensors have shown potential for the rapid detection of foodborne pathogens. In this study, an impedimetric biosensor was developed for rapid detection of Salmonella typhimurium. To develop the biosensor, an interdigitated microelectrode (IME) was fabricated by using semiconductor fabrication process. Anti-Salmonella antibodies were immobilized based on either avidin-biotin binding or self assembled monolayer (SAM) on the surface of the IME to form an active sensing layer. To evaluate effect of antibody immobilization methods on sensitivity of the sensor, detection limit of the biosensor was analyzed with Salmonella samples innoculated in phosphate buffered saline (PBS) or food extract. The impedimetric biosensor based on SAM immobilization method produced better detection limit. The biosensor could detect 107 CFU/mL of Salmonella in pork meat extract. This method may provide a simple, rapid, and sensitive method to detect foodborne pathogens.