剛體要素法에 의한 內壓容器의 彈塑性解析

權宅鎭,金勝德,朴剛根 成均館大學校 科學技術硏究所 1986 論文集 Vol.37 No.1

The rigid element method(R. E. M. ) is a kind of the numerical discretization techniques for approximate solution of complex problems and is developed for elasto-plastic analysis of wall-type precast reinforced concrete structure. This method that is domain-type analytical method is trying and developing in order to be applied to the continuum. In this paper, it is derived the coordinate transformation matrix[T] and the generalized adaptation matrix[A] of spherical element to be able to apply to analysis of hemispherical shell supported with a cylindrical shell, established and formulated the analytical method. And then it is developed a computer program that is designated EPAREM-Ⅳ (Elasto-Plastic Analysis by Rigid Element Method-Ⅳ) and applied to elasto-plastic analysis of the internal pressure vessel. In addition, it is analyzed and considered the results, in the future, as basic study that shall analyze more difficult problems in structural engineering.

세포질내 정자주입법(ICSI)에 있어서 정자흡입 및 난자내 주입방법에 관한 연구

이택후,김항진,송건호,김대근,전상식,박윤규,서태광,전병균,류은경,이은숙,문진수,김광철 경북대학교 의학연구소 2000 경북대학교병원의학연구소논문집 Vol.4 No.1

Study on Method of Sperm Aspiration and Injection into an Oocyte in Intracytoplasmic Sperm Injection(ICSI) Immobilization of spermatozoa prior to intracytoplasmic sperm iniection(ICSI) sometimes results in crooked tail and this makes it difficult to aspirate sperm into an injection pipette tail first. Head-first sperm aspiration into an injection pipette avoid this problem due to the bigger size of the sperm head. The effect of head or tail-first sperm injection into an oocyte on fertilization cleavage, percentage of grade I embryos and development to blastocyst stage in ICSI program has been studied. A single living immobilized spermatozoa from oligoasthenozoospermic patient was injected into an oocyte head-first or tail-first according to the treatment. Eighteen hours after microinjection, oocytes ware inspected for survival and fertilization Fertilized oocytes with two pronuclei were cultured in 30μl drop of mHTF supplemented with 10% heat-inactivated follicular fluid(FF) at 37℃. On day 2. embryo transfer was performed with cleaved embryos. The remaining 2-8 cell stage embryos were co-cultured with BRL cells in mHTF + 10% FF for 72 hours and the developmental stage was observed. The data were analyzed by Analysis of Variance. A total of 164 oocytes from 36 cycles were assigned to earth treatment and ICSI was performed(88 head-first, tail-first). The rates of normal fertilization were 81.8% and 76.3% for head-first and tail-first, respectively. Of the fertilized oocytes, the percentage of cleaved embryos and the percentage of grade 1 embryo among cleaved embryos were 88.9% and 68.8%, 93.1% and 74.1% for head-first and tail-first, respectively. Of the 2-8 cell embryos cultured, 44.4%(16/36) and 50.0%(10/20) for head first and tail first, respectively developed to blastocyst stage. There were no differences in fertilization, cleavage, rates of grade 1 embryos, and development to blastocyst stage. In conclusion, head-first or tail-first sperm injection into an oocyte in ICSI program does not affect fertilization and subsequent embryo development to blastocyst stage in vitro.

剛體要素法으로 휨이 考慮된 쉘要素를 利用한 內壓容器의 彈塑性解析

權宅鎭,金勝德,朴剛根 成均館大學校 科學技術硏究所 1986 論文集 Vol.37 No.2

The Rigid Element Method(R.E.M) is a kind of the numerical discretization, techniques, such as the finite element method or the boundary element method, for getting the approximate solution of continuum mechanics problem. This method is originally developed for elasto-plastic analysis of wall-type precast reinforced concrete structures. In R.E.M., each discreted element is regarded as rigid body and the elements are interconnected with virtual springs with the stiffness of element. The springs transmit the axial force, the shear force and the normal force. The degree of freedom is placed in an arbitrary point within the element and the rigid displacements of this point affect other element through the springs being around the element. In this paper, it is derived the generalized adaptation matrix of shell elements which consider the effect of bending moment in thickness direction and developed a computer program using the present theory. Also, it is analyzed the behaviors of structure, that is, the distribution of stresses, the progress of cracks, the shape of deformation and the mode of fractures, for the hemispherical shell supported on cylinder under internal pressure.

솔잎발효추출물의 효소적 저해활성 및 아질산염 소거작용

홍택근,이용림,임무현,정낙현 한국식품저장유통학회 ( 구 한국농산물저장유통학회 ) 2004 한국식품저장유통학회지 Vol.11 No.1

솔잎의 기능성에 관한 연구를 위하여 솔잎발효추출물(PFE)과 에탄올추출물(PE 80, PE 50)로 효소적 저해활성과 아질산염 소거작용에 대하여 연구하였다. Tyrosinase의 저해효과는 솔잎발효 추출물인 PFE가 솔잎 에탄올 추출물 PE 80과 PE 50에 비해 약 5∼38%정도 저해활성 효과가 높게 나타났다. XOase 저해효과는 PFE가 62.77%, PE 80이 64.90%, PE 50이 55.91%의 저해율을 나타내였으며 ACE저해효과는 PFE가 78.02%, PE 80이 69.82%, PE 50이 21.75%의 순으로 솔잎발효 추출물인 PFE가 가장 높은 저해효과를 나타내었다. 아질산염 소거작용은 솔잎추출물 모두 pH 3.0이하에서 높은 분해능력을 나타내였다. 유기산 함량 분석 결과, PFE, PE 80, PE 50의 세 시료 모두 항산화작용에 관여하는 ascorbi acid가 가장 많이 함유되어 있었으며, 시료별 ascorbic acid의 함량은 솔잎 발효추출물인 PFE가 가장 많이 함유되어 있는 것으로 나타났다. Effects on the physiological functionality, such as tyrosinase, xanthine oxidase, angiotensin converting enzyme and Nitrite scavenging ability were also observed by pine needle fermentation extract(PFE) and the difference in the consistency of pine needle ethanol extracts(PE 80, PE 50) was found. In the inhibition effect on tyrosinase, PFEP showed 5-38% higher than that of PE 80 and PE 50. In the inhibition on XOase, PFE, PE 80 and PE 50 showed 62.77%, 64.390%, 55.91% respectively. In the inhibition effect on ACE, PFE, PE 80 and PE 50 showed 78.02%, 69.82% and 21.75% respectively. Among these, PFE showed the highest ACE inhibition effect. In the inhibition effect on nitrite scavenging anility, the pine needle extracts showed a high effect in pH 3.0. As the result of the research using HPLC for the organic and, all the samples(PFE, PE 80, PE 50) showed higher contents of the ascorbic acid concerned with the effect of the antioxidative. PFE showed the highest contents of the ascorbic acid.

有限要素法에 의한 슬래브를 가지는 3次元 骨造構造物의 靜·動的 解析에 관한 硏究

서상근,허택영,장병순 釜山大學校生産技術硏究所 1995 生産技術硏究所論文集 Vol.49 No.-

슬래브를 가지는 3차원 골조구조물에 진동을 유발하는 기계하중이 재하되면, 동적 거동을 고려하여 구조물을 설계할 필요가 있다. 구조물의 정.동적 해석에서 보다 정확한 해를 얻기위해 기하학적 형상, 재료특성, 경계조건 및 하중조건 등을 실제 구조물에 근접하도록 이상화시켜야 한다. 본 연구에서는 구조물 해석에 유한요소법을 사용하였으며, 본 연구의 목적은 동적 하중을 받는 건축구조물에 대한 동적 운동방정식의 정식화 및 구조물 해석에 적용할 수 있는 프로그램의 개발이며 이 프로그램으로 슬래브 임의 위치에서 진동하는 기계가 재하될 때 구조물의 동적 거동을 해석하는 것이다. When dynamic force such as mechanical load which create vibration is applied to the three-dimensional framed structure with slab, dynamic analysis is an essential part of the design work. In order to obtain the accurate result of either static or dynamic analysis, idealization of geometrical shape, material properties, boundary conditions and loading conditions have to be as close to the actuality. The aim of this study is formulation of the equation for dynamic motion and development of finite element program which can be accommodated to analysis of dynamic behavior of building structures.

Effect of Free Surface Based on Submergence Depth of Underwater Vehicle

Taek-Geun Youn,Min-Jae Kim,Moon-Chan Kim,Jin-Gu Kang 한국해양공학회 2022 韓國海洋工學會誌 Vol.36 No.2

This paper presents the minimum submergence depth of an underwater vehicle that can remove the effect of free surface on the resistance of the underwater vehicle. The total resistance of the underwater vehicle in fully submerged modes comprises only viscous pressure and friction resistances, and no wave resistance should be present, based on the free surface effect. In a model test performed in this study, the resistance is measured in the range of 2 to 10 kn (1.03–5.14 m/s) under depth conditions of 850 mm (2.6D) and 1250 mm (3.8D), respectively, and the residual resistance coefficients are compared. Subsequently, resistance analysis is performed via computational fluid dynamics (CFD) simulation to investigate the free surface effect based on various submergence depths. First, the numerical analysis results in the absence of free surface conditions and the model test results are compared to show the tendency of the resistance coefficients and the reliability of the CFD simulation results. Subsequently, numerical analysis results of submergence depth presented in a reference paper are compared with the model test results. These two sets of results confirm that the resistance increased due to the free surface effect as the high speed and depth approach the free surface. Therefore, to identify a fully submerged depth that is not affected by the free surface effect, case studies for various depths are conducted via numerical analysis, and a correlation for the fully submerged depth based on the Froude number of an underwater vehicle is derived.

Agmatine Reduces Hydrogen Peroxide in Mesangial Cells under High Glucose Conditions

( Geun Taek Lee ),( Hun Joo Ha ),( Hyun Chul Lee ),( Young Dong Cho ) 생화학분자생물학회 2003 BMB Reports Vol.36 No.3

Agmatine, an amine and organic cataion, reduced H₂O₂ that was generated by hyperglycemia, and transcription factors such as NF-кB and AP-1 activity in the mesangial cells that were exposed to high glucose. However, spermine which shares a strong nucleophillic structure with agmatine decreased the H₂O₂levels and AP-1, but not the NF-кB activity. Possible roles for agmatine and spermine in decreasing fibronectin are discussed, and the signaling pathway for agmatine-reduced fibronectin accumulation is presented.

Identification of in vivo substrate for transglutaminase from soybean ( Glycine max )

Geun Taek Lee,Hyeog Kang,Young Dong Cho 생화학분자생물학회 1997 생화학분자생물학회 춘계학술발표논문집 Vol.- No.-

P121 : Nevus sebaceous with sebaceoma and intradermal nevus

( Taek Geun Lee ),( Seung Hyun Moon ),( Hyun Hwang Bo ),( Teag Wang Kwon ),( Hyun Ho Son ),( Sook Kyung Lee ) 대한피부과학회 2014 대한피부과학회 학술발표대회집 Vol.66 No.1

A Study on Effective Satellite Selection Method for Multi-Constellation GNSS

Taek Geun Lee,Yu Dam Lee,Hyung Keun Lee 사단법인 항법시스템학회 2023 Journal of Positioning, Navigation, and Timing Vol.12 No.1

In this paper, we propose an efficient satellite selection method for multi-constellation GNSS. The number of visible satellites has increased dramatically recently due to multi-constellation GNSS. By the increased availability, the overall GNSS performance can be improved. Whereas, due to the increase of the number of visible satellites, the computational burden in implementing advanced processing such as integer ambiguity resolution and fault detection can be increased considerably. As widely known, the optimal satellite selection method requires very large computational burden and its realtime implementation is practically impossible. To reduce computational burden, several sub-optimal but efficient satellite selection methods have been proposed recently. However, these methods are prone to the local optimum problem and do not fully utilize the information redundancy between different constellation systems. To solve this problem, the proposed method utilizes the inter-system biases and geometric assignments. As a result, the proposed method can be implemented in real-time, avoids the local optimum problem, and does not exclude any single-satellite constellation. The performance of the proposed method is compared with the optimal method and two popular sub-optimal methods by a simulation and an experiment.