댐 붕괴 흐름에 의한 직립 홍수터의 범람 실험 및 모의

황승용(Hwang, Seung-Yong),김형석(Kim, Hyung Suk) 대한토목학회 2021 대한토목학회논문집 Vol.41 No.3

불연속 지형을 지나는 천수 흐름을 해석할 수 있는 Hwang의 기법이 채택된 수치 모의를 댐 붕괴 흐름에 의한 직립 홍수터의 범람 실험과 비교하였다. 모의 결과는 저수지, 저수로, 홍수터로 이루어진 실험 수로에서 측정한 결과와 잘 일치하였다. 특히, 댐 붕괴 흐름이 직립 홍수터로 차고 빠지는 과정이 잘 모의되었다. 흐름 저항의 종류에 따른 모의 결과의 차이는 미미하였다. 이 연구를 바탕으로 도심 하천의 범람 예측에서 정확도를 높일 수 있을 것으로 기대된다. Numerical simulation with Hwang’s scheme, which can analyze shallow-water flow over discontinuous topography, was compared with a laboratory experiment of flooding on a perpendicular floodplain with dam-break flows. The simulation results were in good agreement with the results measured in an experimental flume with a reservoir, channel, and floodplain. The wetting and drying process on a perpendicular floodplain with a dam-break flow was particularly well simulated. The difference in simulation results according to the type of flow resistance was insignificant. The results of this study are expected to improve the accuracy of predicting inundation in urban rivers.

꽃게껍질로 제조된 키토산의 항균효과

황용일,이광현,이승철,하정욱 慶南大學校 附設 工業技術硏究所 1998 硏究論文集 Vol.15 No.3

고분자당류인 chitosan은 가식성 포장제, 항암제, 생물응집제, 항균물질 등으로 폭넓은 이용성을 갖는다. 다량으로 폐기되고 있는 갑각류의 껍질을 효율적으로 이용하게 위하여 꽃게 껍질에서 chitin을 분리정제한 후 탈아세틸화하여 chitosan을 제조하였다. 제조된 chitosan중에서 분자량 42,000이 Escherichia coli O157:NM에 항균력이 가장 우수하였다. 이들 결과로 부터 각종 식중독균에 대하여 항균력을 조사하였다 항균력시험으로 부터 식중독균 중에서 Gram음성균 보다 양성균에 대하여 효과적이 였으며, Gram음성균 중에서도 균종에 따라 상이한 항균력을 보였다. Chitosan was well known as an available material preparing for edible film, antiturmor agent, biocoagulant, and antimicrobiotics etc. For the effective use of Crustacean shell, chitin was prepared from the shell of Blue crab, and chitosan was made through the deacetylation of above chitin. Prepared chitosan with 42,000 M.W. showed most antibacterial effect for Escherichia coli O157 : NM. From this result, chitosan was tested its antibacterial reaction for some Gram prositive and negative food-poisoning bacteria. Antibacterial effect of chitosan was more higher for Gram positive bacteria than Gram negative bacteria and its antibacterial reactions were different for species of Gram negative bacteria.

급성 포름알데히드 가스 흡입에 의한 흰쥐 후각상피의 형태학적 변화

백선용,전재기,문용석,황승영,노환중,고의경,왕수건 대한해부학회 1998 Anatomy & Cell Biology Vol.31 No.3

점액성췌장 낭종 1예

황석주,김영운,오성광,김대영,임선재,박승욱,이두용,이헌영 충남대학교 의과대학 지역사회의학연구소 1995 충남의대잡지 Vol.22 No.2

Pancreatic cystadenoma is very rare, slow growing tumor and generally preoperative differential diagnosis may be difficult. A 43-year-old female was admitted to our hospital with the complaint of abdominal discomfort in the epigastrium for about preceeding 5 years. Ultrasonography and Computed tomography were performed. When endoscopic retrograde cholangio-pancreatogram was performed, displacement of distal pancreatic duct by huge mass was noted and injected dye was drained irregulary into the cavity of mass. Distal pancreatectomy was performed with splenectomy. The mass size of distal pancreas was 7X4cm, and the cyst contained with yellowish thick mucoid fluid. Diagnosis was confirmed the mutinous cystadenoma of the pancreas on histologic examination.

적응 루프법을 이용한 진화적 구조 위상 최적설계

황승민,박재용,임민규,오영규,한석영 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-

This paper presents a reliability-based topology optimization (RBTO) using bi-directional evolutionary structural optimization (BESO). Topology optimization is formulated as volume minimization problem with probabilistic displacement constraint. Young's modulus, external load and thickness are considered as uncertain variables. In order to compute reliability index, four methods, i.e., RIA, PMA, SLSV and ADL(adaptive-loop), are used. Reliability-based topology optimization design process is conducted to obtain optimal topology satisfying displacement and reliability index constraints with the above four methods, and then each result is compared with respect to numerical stability and computing time.

카메라 초점 오차에 강건한 패턴 정합

황수용,이상이,이승현 서울産業大學校 1996 논문집 Vol.44 No.1

We investigate the performance of robust pattern matching for defocused images used to recognize an object. The matching method uses the nonlinear joint transform correlator(NJTC) which is able to change the relative contribution of the phase and amplitude signals. Here the nonlinearty is used to make the robustness of the camera focusing. Computer simulation is used to show the correlation peak intensity, peak intensity, peak-to sidelobe ratio for defocused images.

직각 광정 위어를 지나는 천수 흐름의 수치 해석

황승용,Hwang, Seung-Yong 한국수자원학회 2022 한국수자원학회논문집 Vol.55 No.10

불연속 지형 전면에 작용하는 정수압 분포에 실제 압력과 차이를 해명하는 흐름률 보정 계수를 도입하여 불연속 지형을 직접 해석하는 Hwang의 기법이 적용된 수치 모형의 정확도를 높일 수 있었다. 218개 실험 시행으로 직각 광정 위어의 월류량에 가장 적합한 계수를 결정하였으며, 이것을 별도의 두 가지 직립 광정 위어 실험과 측면 위어 부정류 실험에 적용해보니 실험과 모의에서 월류량이 서로 잘 일치하였다. 이로써 조밀한 격자로 불연속 지형을 완화하거나 내부 경계를 부여하지 않고도 직각 광정 위어와 같은 불연속 하천 구조물을 지나는 천수 흐름의 정확한 수치 모의가 가능해졌다.

산업용 로봇의 일정한 방향성 생성

이승황,양승한,박용국 한국공작기계학회 2001 한국생산제조학회지 Vol.10 No.2

In general, there are many degrees of freedom(DOFs) in industrial robot. So they have many poses of several special end-effector's positions and orientations. For that reason, industrial robots are used in a wide scope of industrial applica-tions such as welding, spray painting, deburring, and so on. In this research, an off-line continuous path planning method based on linear interpolation with parabolic blend is developed. The method safely maintains the constant orientation for base frame and end-effector's path within allowable error and minimizes the number of segments in path. This algorithm may apply to welding and painting in which the orientation is particularly significant. The simulation study of cartesian curve is carried out to show the performance of this algorithm.

미세캡슐화 커피 분말의 제조 및 특성

이승철,황용일 慶南大學校 附設 基礎科學硏究所 1998 硏究論文集 Vol.12 No.-

Microencapsulation processes are widely used in food industry, including flavors, preservatives, and food additives. We studied the preparation of microencapsulated coffee powder with a spray drying method using wall material as the mixture of gum arabic : maltodextrin (1 :4, w : w). Electron micrographs showed that microencapsulated coffee powders were generally spherical shaped with a diameter 20∼40 ㎛ larger than spray dried coffee powders (diameter 15∼30 ㎛). while freeze dried ones were shown to have an angular shape. In color determination, freeze dried coffee had the nearest values to natural raw coffee, and the microencapsulated coffee had lighter color. Water activity of the microencapsulated coffee was 0.15, and those of freeze dried ones and spray dried ones were 0.16, and 0.18, respectively. With the above results. the microencapsulation process could be applied to coffee for effective preservation of flavor and for long shelf life.

순차적 크리깅기법을 이용한 미소혼합기의 최적화

박재용,유진식,황승민,임민규,오영규,김용대,한석영,맹주성 한국공작기계학회 2008 한국공작기계학회 추계학술대회논문집 Vol.2008 No.-

An active micro-mixer, which is composed of an oscillating micro-stirrer in the micro-channel to provide effective mixing was optimized. The effects of molecular diffusion and disturbance by the stirrer were considered with regard to two types of mixer models: the simple straight micro-channel and micro-channel with an oscillating stirrer. Two types of mixer models were studied by analyzing mixing behaviors such as their interaction after the stirrer. The mixing was calculated by Lattice Boltzmann methods using the D2Q9 model. In this study, the time-averaged mixing index formula was used to estimate the mixing performance of time-dependent flow. The mixing indices of the two models were compared. From the results, it was found that the mixer with an oscillating stirrer was much more enhanced' and stabilized. Therefore, an approximate optimization of an active micro-mixer with an oscillating stirrer was performed using Kriging method with OLHD (Optimal Latin Hypercube Design) in order to determine the optimal design variables. The design parameters were established as the frequency, the length and the angle of the stirrer. The optimal values were obtained as 1.5754, 0.803D and ±45°, respectively. It was found that the mixing index of the optimal design increased by 83.36% compared with that of the original design.