• Fisheries and Aquatic Sciences
• /
• 제13권2호
• /
• pp.167-181
• /
• 2010

To predict changes in the marine environment of the Beolgyo Stream Estuary in Jeonnam Province, South Korea, where cohesive tidal flats cover a broad area and a large bridge is under construction, this study conducted numerical simulations involving tidal flow and cohesive sediment transport. A wetting and drying (WAD) technique for tidal flats from the Princeton Ocean Model (POM) was applied to a large-scale-grid hydrodynamic module capable of evaluating the flow resistance of structures. Derivation of the eddy viscosity coefficient for wakes created by structures was accomplished through the explicit use of shear velocity and Chezy's average velocity. Furthermore, various field observations, including of tide, tidal flow, suspended sediment concentrations, bottom sediments, and water depth, were performed to verify the model and obtain input data for it. In particular, geologic parameters related to the evaluation of settling velocity and critical shear stresses for erosion and deposition were observed, and numerical tests for the representation of suspended sediment concentrations were performed to determine proper values for the empirical coefficients in the sediment transport module. According to the simulation results, the velocity variation was particularly prominent around the piers in the tidal channel. Erosion occurred mainly along the tidal channels near the piers, where bridge structures reduced the flow cross section, creating strong flow. In contrast, in the rear area of the structure, where the flow was relatively weak due to the formation of eddies, deposition and moderated erosion were predicted. In estuaries and coastal waters, changes in the flow environment caused by artificial structures can produce changes in the sedimentary environment, which in turn can affect the local marine ecosystem. The numerical model proposed in this study will enable systematic prediction of changes to flow and sedimentary environments caused by the construction of artificial structures.

• 한방재활의학과학회지
• /
• 제19권2호
• /
• pp.27-49
• /
• 2009

Objectives : The purpose of this study was to investigate the effects of Yanghyuljanggeungunbo-tang(Yangxuezhuangjinjianbu-tang) and Cervi Cornu Parvum pharmaco-acupuncture in Spinal Cord Injury(SCI)-induced rats. Methods : The subjects were divided into 5 groups ; Normal, Control no treatment after SCI, Experimental I taken with Yanghyuljanggeungunbo-tang (Yangxuezhuangjinjianbu-tang) 500 mg/kg $0.5m{\ell}$ daily after inducing SCI. Experimental II taken with Cervi Cornu Parvum pharmaco-acupuncture at Taegye(KI3) and $Yangnungch{\acute{o}}n$(GB34) after inducing SCI and Experimental III taken with Yanghyuljanggeungunbo-tang(Yangxuezhuangjinjianbu-tang) 500 mg/kg $0.5m{\ell}$ and Cervi Cornu Parvum pharmaco-acupuncture at KI3 and GB34 to SCI-induced rats. After each operation, the present author observed the motor behavior recovery and nerve regeneration by analysis of the motor behavior tests, EMG, hematological(AST, ALT, WBC), histological and immunological changes. Rats were tested at modified Tarlov test at the 1st, 2nd, 3rd, 4th day, and Motor behavior test at 1st, 3rd, 7th, 14th, 21st day. Results : Results are as follows. 1. All the experimental groups were improved compared with control group in the motor behavior tests including Tarlov test, Basso-Beattle-Bresnahan locomotor rating scale, modified inclined plane test, open field test, grid walk test and narrow beam test. Especially Experimental III was improved significantly among other groups. 2. In EMG test, H wave appeared weak only in Experimental III. And M wave was increased significantly in Experimental III. 3. All the experimental groups were significantly decreased compared with control group in serum AST, serum ALT and serum WBC tests. 4. significantly decreased in Tumor Necrosis Factor-${\alpha}$ test compared with the first day of SCI. 5. Muscle contraction and denaturation of all the experimental groups were inhibited in histological observations of gastrocnemius muscle. Especially, those of experimental III was more effective. 6. NGF and BDNF of spinal cord gray matter in all the experimental groups were increased compared with control group. Especially, those of experimental III was more effective. Conclusions : As above, it can be suggested that Yanghyuljanggeungunbo-tang(Yangxuezhuangjinjianbu-tang) and Cervi Cornu Parvum pharmaco-acupuncture may improve motor behavior, EMG, hematological, histological and immunological findings in Spinal Cord Injury(SCI)-induced rats. Especially, effects will be somewhat better in combination of these two treatments.

• 천문학회지
• /
• 제36권4호
• /
• pp.271-282
• /
• 2003

We present results of a $H^{13}CN$ J=1-0 mapping survey of molecular clouds toward the Galactic Center (GC) region of $-1.6^{\circ}{\le}{\iota}{\le}2^{\circ}$ and $-0.23^{\circ}{\le}b{\le}0.30^{\circ}$ with 2' grid resolution. The $H^{13}CN$ emissions show similar distribution and velocity structures to those of the $H^{12}CN$ emissions, but are found to better trace the feature saturated with $H^{12}CN$ (1-0). The bright components among multi-components of $H^{12}CN$ line profiles usually appear in the $H^{13}CN$ line while most of the dynamically forbidden, weak $H^{12}CN$ components are seldom detected in the $H^{13}CN$ line. We also present results of other complementary observations in $^{12}CO$ (J=1-0) and $^{13}CO$ (J=1-0) lines to estimate physical quantities of the GC clouds, such as fractional abundance of HCN isotopes and mass of the GC cloud complexes. We confirm that the GC has very rich chemistry. The overall fractional abundance of $H^{12}CN$ and $H^{13}CN$ relative to $H_2$ in the GC region is found to be significantly higher than those of any other regions, such as star forming region and dark cloud. Especially cloud complexes nearer to the GC tend to have various higher abundance of HCN. Total mass of the HCN molecular clouds within $[{\iota}]{\le}6^{\circ}$ is estimated to be ${\~}2 {\times}10^7\;M_{\bigodot}$ using the abundances of HCN isotopes, which is fairly consistent with previous other estimates. Masses of four main complexes in the GC range from a few $10^5$ to ${\~}10^7\;M_{\bigodot}$ All the HCN spectra with multi-components for the four main cloud complexes were investigated to compare the line widths of the complexes. The largest mode (45 km $s^{-1}$) of the FWHM distributions among the complexes is in the Clump 2. The value of the mode tends to be smaller at the farther complexes from the GC.

• 한국수자원학회논문집
• /
• 제43권8호
• /
• pp.747-755
• /
• 2010

지금까지 분포형 모형은 개념적 모형에 비해 운동역학적인 이론에 근거하여 물의 흐름을 수치해석으로 추적해 나가기 때문에 많은 컴퓨터 메모리용량이 요구되고 계산수행시간이 상대적으로 오래 걸리는 단점이 있었다. 그래서 분포형모형의 적용은 주로 소유역에 국한되어 적용되어왔으며, 대유역에 적용하기 위해서는 격자의 해상도를 낮추거나 소유역 적용과 동일한 해상도에서는 계산 시간이 많이 소요되어 실무적용을 어렵게 하는 요인이 되어왔다. 이에 대해 본 연구에서는 MPI (Message Passing Interface)기법을 적용하여 물리적이고 복잡한 수치계산을 하는 분포형모형의 단점 중 하나인 대유역 적용시의 계산소요 문제를 해결하고자 하였다. 또한 병렬화 기법의 적용효과를 분석하기 위하여 단일 영역에서 계산된 결과와 다수의 소영역으로 분할하여 수행되어진 계산 결과를 비교하였다. 용담댐 유역에 2006년 태풍 '에위니아' 사상을 대상으로 병렬화 계산을 수행한 결과 단일 프로세서에서 분포형모형을 수행하는 것보다 병렬코드에서 수행한 경우가 유출계산 값의 변동 없이 최고 10배에 해당되는 계산시간이 단축되었다.

• 한국터널지하공간학회 논문집
• /
• 제11권1호
• /
• pp.11-22
• /
• 2009

터널 굴착 대상지반의 강도 및 강성이 낮은 경우 막장안정성을 확보하기 위해 분할굴착공법 또는 적절한 보조공법을 병용한다. 본 연구에서는 기존 문헌을 중심으로 막장평가 기법에 대해 정리하고 보조벤치 병용 전단면공법 적용 시 지반의 변형 강도특성에 따른 막장보강의 필요성 유무와 보조공법으로 페이스볼트를 채택할 경우 타설 길이, 타설 밀도, 보강범위에 따라 막장 및 막장주변지반에 어떠한 영향이 발생되는지를 알아보기 위해 3차원 유한요소해석을 수행하였다. 막장 안정성에 대해 문헌에 의한 이론적인 평가기법과 FEM수치해석결과를 비교 분석한 결과 상대적인 차이는 있으나 막장볼트를 통한 막장안정의 효과에는 일치하는 경향을 보였다. 검토대상 지반조건에 대해 막장볼트의 타설형태는 길이 1.0D(D:터널 폭)이상, 격자상 타설(1개/$1.5\;m^2$), 상부 반단면 $120^{\circ}$ 보강시 가장 효과적인 것으로 분석되었다.