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서병성,김준연,김정만,김용규,정갑열,김성환,김인식,김병권 동아대학교 부설 산업의학연구소 1997 산업의학연구소 논총 Vol.- No.3
This experiment was carried out to compare the efficacy of 2,3-dimercaptosuccinic acid(DMSA) and calcium ethylenediamine tetraacetate(CaEDTA) as chelating agents for lead poisoning. The rats had been fed water containing 0.5% lead acetate for 3 months and randomly divided into three groups. We administered DMSA only for group I(n=5), CaEDTA only for group II(n=5), and both DMSA and CaEDTA for group III(n=10), for 4 days. We evaluated urinary lead(PbU) level, blood lead(PbB) level and blood zinc protoporphyrin(ZPP) level before and after administration of the chelating agents. The results obtained were as follows; 1. After administration of chelating agents, the mean PbU levels, which were 248.2㎍/dl, 252.6㎍/dl and 270.0㎍/dl in group I, II and III before administration, were increased to 484.6㎍/dl, 479.9㎍/dl and 1,792.1㎍/dl in group I, II and III, respectively(p<0.05). 2. After administration of chelating agents, the mean PbB levels, which were 67.4㎍/dl, 59.9㎍/dl and 62.5㎍/dl in group I, II and III before administration, were decreased to 38.1㎍/dl, 36.3㎍/dl and 31.3㎍/dl in group I, II and III, respectively(p<0.05), but there were no different changes of ZPP level among groups. 3. The blood lead clearances, which were calculated by PbB level before and after administration of chelating agents, were 49.8%, 43.5% and 39.5% in group III, I and II, respectively.
Numerical Modeling of Static Shear Behavior in Interfaces
Inn Joon Park,Chang Won Kwak,Jun Boum Park 한국지반공학회 2012 international journal of geo-engineering Vol.4 No.3
A constitutive model based on elasto-plasticity theory is modified and proposed here to describe the behavior of interfaces subjected to static loading conditions. The proposed model is developed in a hierarchical manner wherein a basic model describing simplified characteristics of the interfaces is modified by introducing different features, to model increasingly complex behavior of the interfaces. The parameters influencing interface behavior are identified using data from laboratory simple shear tests on sand-steel interfaces, Proposed model is verified with respect to comprehensive test data on interfaces with different roughness, normal loads and initial densities, A highly efficient algorithm is developed and modified to perform drill correction under constraint condition, This algorithm is used for the integration of constitutive relation for interfaces to perform back prediction, The proposed model far the interfaces is used in the context of the thin-layer element approach and is implemented in a nonlinear finite element code to solve a boundary value problem. The findings of this research have contributed to the understanding of the interface behavior in soil-structure interaction problems. The proposed model can simulate a number of important behaviors with respect to the interfaces.
Disturbed State Modeling for Dynamic Analysis of Soil-Structure Interface
Park, Inn-Joon,Yoo, Ji-Hyeung,Kim, Soo-Il 한국지반공학회 2000 지반 : 한국지반공학회지 Vol.16 No.3
본 연구에서 흙(사질토)-구조물의 경계면에 대한 거동특성을 분석하기 위하여 교란상태개념(DSC)을 수정 및 보완하였다. 제안한 DSC모델에서는 변형중인 재료는 상대적으로 손상되지 않은 상태(RI)와 완전 파괴된 상태(FA)가 혼합되어있다는 가정에 기초를 두고 있다. RI 상태는 HiSS모델을 이용하였고, FA 상태는 한계상태모델을 이용하였다. 이런 DSC 모델을 Biot이론에 기초한 기존 유한요소 프로그램에 접목하였다. 본 연구에서 수저한 유한요소 프로그램을 이용하여 실제 경계면 실험(두 가지 하중조건: 정하중, 동하중)에 대하여 모의실험을 수행하였다. 또한 그 결과와 실내시험결과를 비교 검토하였다. DSC모델을 이용한 유한요소해석은 실제 실내시험 결과와 유사한 경향을 보였다. 본 연구의 결과를 통하여, DSC모델을 흙-구조물 경계면 해석에 비교적 합리적인 결과를 제공한다고 판단된다. In this study, the Disturbed State Concept (DSC) constitutive model is calibrated and modified for steel-sand interface by using the HiS S model for relative intact (Rl) state and the critical state model for the fuBy adjusted (FA) part in the material. The general formulation for implementation is developed. Then, the DSC model with modification for interface is implemented in finite element program based on the generalized Biot's theory. The interface test under one-way monotonic and two-way cyclic loading were numerically simulated using the finite element program modified in this study. The DSC predictions show improved agreement with the observed results from laboratory test. Overall, the computer procedure with the DSC allows relatively improved simulation ofthe soil-structure interaction problems.oblems.