• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1179-1183
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• 2007

관망 내에서 흐름의 연속 방정식과 운동량 방정식을 상 미분으로 전개하여 해석한 특성선 방법은 주로 가압 관망체계(Pressurized Pipeline System)에서의 부정류 해석(Unsteady Analysis)에 사용 된다. 그러나 이특성선 방법은 천이류 해석을 위한 관망 재구성 과정에서 Courant수 조건의 만족을 위한 관의 재배열에 천문학적인 계산용량과 시간이 필요하다는 단점이 있다. 이는 현장 적용 시 압력파 전파속도의 불확실성과 연계되어 상당한 장해요소가 되고 있다. 이에 대안적인 방법으로서 임펄스응답법이 개발되었다. 이는 경계지점에서 복소수 유량에 대한 복소수 수두의 비율로써 정의된 관망에서의 수리임피던스를 역퓨리에 변환에 적용하여, 주파수 영역의 수치를 시간 영역으로 변환하여 응답함수를 산출한 후, 산출된 응답함수와 구해진 경계지점에서의 유량과의 적분을 통하여 임의의 지점에서의 수두 및 유량을 계산하는 방법이다. 임펄스 응답법은 관 부속물관의 특성을 기술하는 수학적 표현의 난해함으로 인해 지금까지는 단일관에 대한 연구에만 국한되어 왔다. 본 연구에서는 임펄스응답법을 수리구조물이 부착된 관망에 적용하여 다양한 조건에서 천이류 분석을 시행하였다. 즉, 에어챔버 및 서지탱크와 같은 수리구조물을 각각에 대한 수리임피던스를 구하고, 가지관 및 통합 관성항으로 취급하여 수리구조물을 처리하였다. 그리고 이러한 결과를 특성선방법과 비교하여 그 적절성을 검증하였는데, 특성선 방법에 의한 모의 결과와 비교하였을 때, 일치하는 결과를 나타내었다. 임펄스응답법에 의한 모의 결과에서 감쇄효과를 과대평가하는 경향이 관찰되었다. 이는 임펄스 응답법의 가정에 기인한 것으로써 난류 상태의 흐름에서 상당한 불일치를 가져올 수 있으나, 수리 구조물에 의한 수격압이 감쇄되는 과정에서 대부분 흐름이 층류 상태로 전환된다고 가정 할 때는 상당한 적용성이 있다. 본 연구는 수리구조물이 부착된 관망의 해석함에 있어서 임펄스응답법의 적용이 가능함을 보였고, 이는 보다 복잡한 관망에서의 천이류 해석이 가능함을 시사한다.

• Korean Journal of Microbiology
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• v.44 no.2
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• pp.110-115
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• 2008

Acridine was not a substrate for fungal laccase but it was oxidized to acridone in the culture medium of P. cinnabarinus SCH-3. During the cultivation of P. cinnabarinus SCH-3, Laccase was the predominant extracellular phenoloxidase, and 3-hydroxyanthranilic acid (3-HAA) was produced in the early culture. Cinnabarinic acid (CA) was observed to accumulate in the culture medium. When P. cinnabarinus was grown in the culture medium containing acridine, acridine was oxidized to acridone. But when the laccase purified from the culture medium of P. cinnabarinus directly reacted with acridine in sodium tartrate buffer (pH 3.0), The oxidation of acridine did not happen. In contrast, when 3-HAA was added to the buffer that was mixed with laccase and acridine, the acridine was oxidized to acridone. While in vitro studies, the CA was formed from 3-HAA in the presence of purified laccase. The results suggest that the acridine should be oxidized to the acridone through the mediation of 3-HAA by the laccase in the culture medium of P. cinnabarinus SCH-3.

• KSBB Journal
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• v.17 no.6
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• pp.515-519
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• 2002

The changes in the levels of total soluble protein and some free amino acids were investigated in germinating brown rice. Nongerminated (N) brown rice was germinated for 72 hrs by applying following solutions: 1) distilled water (W), 2) 50 ppm chitosan in 5 mM lactic acid (CL), and 4) 50 ppm chitosan in 5 mM glutamic acid (CG). The level of total soluble protein was higher in the N extract than those of W, CL and CG. Alanine levels were enhanced and aspartic acid levels were decreased significantly in the germinated brown rice, highest increases of alanine were found in the CG germinated brown rice. The levels of serine, decreased during germination in solutions W and CL, were increased significantly by germination in CG solution. The levels of essential amino acids, such as Iysine, isoleucine and methionine were also increased significantly by germination in CG solution. Our results show that the germination of brown rice with CG solution can significantly increase the levels of alanine and some other essential amino acids and can restore the serine level.

• Journal of Plant Biology
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• v.35 no.3
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• pp.273-281
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• 1992

The origin of the interfascicular cambium from residual meristem can be elucidated by tangential and transverse observation. It is clear that there is structural distinction between interprocambial and interfascicular residual meristem and adjacent parenchyma in both the transverse and tangential view. Consequently, the residual meristem does not convert into parenchyma but, rather, becomes interfascicular cambium. In tangential view, the homogeneous structure of interfascicular residual meristem at an early stage changes gradually into a heterogeneous one at a later stage, with long and short cells from which fusiform and ray initials originate respectively. However, the homogeneous structure of parenchyma adjacent interfascicular residual meristem does not change into a heterogeneous one but remains the same at all stages of development. Therefore, the interfascicular cambium has a direct ontogenetic continuity with the residual meristem, and does not have its secondary origin from differentiated parenchyma. Furthermore, the ontogenetic pattern of the interfascicular cambium is almost the same as that of fascicular cambium.ambium.

• Journal of the Korean Chemical Society
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• v.22 no.4
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• pp.202-220
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• 1978

Uniform semiclassical (WKB) solutions are obtained for nonseparable systems without using a close coupling formalism and are given explicitly in terms of well known analytic functions for various physically interesting and realistic cases. They do not become singular at turning points or surfaces and when taken in their asymptotic forms, they reduce to the usual WKB solutions that could be obtained if the Stokes phenomenon was properly taken care of for solutions. In obtaining such uniform solutions, the Schroedinger equations for nonseparable systems are suitably "renormalized" to solvable "normal" forms through certain transformations. Ehrenfest's adiabatic principle plays an important guiding role for obtaining such "renormalized" uniform solutions for nonseparable systems. The eigenvalues of the Hamiltonian can be calculated from the extended Bohr-Sommerfeld quantization rules when appropriate classical trajectories are obtained. An application is made to many-electron systems and for one of the simplest examples to show the utility of the method the approximate wavefunction is calculated of the ground state helium atom.

• Food Science and Preservation
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• v.9 no.2
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• pp.144-147
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• 2002

This study was conducted to investigate the effect of sub-ingredients of kimchi on the formation of carbon dioxide and vessel pressure. The pH, titratable acidity, formation of carbon dioxide and vessel pressure of kimchi prepared with different sub-ingredients were determined during storage at 10$^{\circ}C$. In the kimhi without GA, the pH decrease and acidity increase was slow during storage, but those of the kimchis without Gl, RP and SA were began to higher from 3th day after storage showed maximum values and was maintained 9th day after storage. The main sub-ingredient for formation of carbon dioxide was garlic and the gas formation was low in the kimchi without garlic. Vessel pressure in kimchi of the latter term of storage generally showed sub-atmospheric pressure and the more formation of carbon dioxide showed the more degree of sub-atmosphere.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.188.2-189
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• 2003

시설재배 만감류인 부지화 감귤의 수확후 저장유통시 부패 감소 및 상품성 제고를 위하여 환경친화적 전처리방법으로서 중온처리의 적용 가능성을 확인하고자, 제주 서귀포산 부지화(한라봉)감귤의 열수 및 열풍 처리에 따른 저장중 품질특성 변화를 살펴보았다. 표면상처가 없는 일정 크기의 건전 과실을 선별한 후, 각각 52$^{\circ}C$에서 2분(52-2m), 6$0^{\circ}C$에서 20초(60-20s) 동안 열수에 침지하거나 45$^{\circ}C$에서 4시간(45-4h), 8시간(45-8h) 동안 열풍을 가한 다음 5$^{\circ}C$에서 냉각 건조하였다. 충분히 냉각된 과실을 통기성 천공 LDPE 필름에 포장하여 5"C에서 21일, 18$^{\circ}C$에서 7일간 저장하면서 생리, 이화학, 관능적 특성을 측정하였다. 중온처리 직후 초기 호흡률은 처리구 모두 무처리구와 비교하여 다소 높았으나, 저장중 처리구 감귤의 호흡률은 감소하여 21일째는 무처리구와 동일한 수준을 나타내었다. 과실내 기체조성은 저장기간 및 처리구간에 차이를 보이지 않았으나 21일부터는 저장온도 전환에 따라 $CO_2$가 다소 증가하는 양상을 보였다. 과실의 pH, 산도, 경도는 중온처리에 따른 유의적 차이를 구분할 수 없었으나, 고형분 함량과 생체 중량감소율은 열풍처리구에서 다소 높게 유지되었다. 과피 표면색 역시 열풍처리구 (45-8h)가 다른 것에 비해 저장중 짙게 나타났으나 열수처리구에서는 가시적 변화를 발견할 수 없었다. 한편 부패과 발생률에 있어서 열수처리구가 축부병 등에 의한 짓무름 현상 및 곰팡이 발생정도를 가장 낮게 나타내었고, 관능검사에서도 열수처리구가 변색, 시듦, 광택 등의 외관 품질항목에서 유의적으로 우수하게 평가되었다. 결과적으로 중온 열수처리는 부지화 김귤의 수확후 저장유통중 부패과 발생률을 감소시키고 외관품질을 유지하는데 효과적인 전처리방법임을 확인할 수 있었다. 있었다.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.1
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• pp.34-42
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• 2001

A battery is the device that transforms the chemical energy into the direct-current electrical energy directly without a mechanical process. Unit cells are connected in series to obtain the required voltage, while being connected in parallel to organize capacity for load current and to decrease the internal resistance for corresponding the sudden shift of the load current. Because the voltage droop down in one set of battery is faster than in tow one, it amy result in the low efficiency of power converter with the voltage drop and cause the system shutdown. However, when the system being driven in parallel, a circular-current can be generated. The changing current differs in each set of battery because the system including batteries, rectifiers and loads is connected in parallel and it makes the charge voltage constant. It is shown that, as a result the new batteries are heated by over-charge and over-discharge, and the over charge current increases rust of the positive grid and consequently shortens the lifetime of the new batteries. The difference between the new batteries and old ones is the amount of internal resistance. In this paper, we can detect the unbalance current using the micro-processor and achieve the balance current by adjusting resistance of each set. The internal resistance of each set becomes constant and the current of charge and discharge comes to be balanced by inserting the external resistance into the system and calculating the change of internal resistance.

• KSBB Journal
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• v.17 no.1
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• pp.49-53
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• 2002

The changes in the levels of $\gamma$ -aminobutyric acid (GABA) and some free amino acids were investigated in germinating brown rices. Ungerminated brown rices were germinated for 72 hrs by application of the following solutions: 1) distilled water, 2) 50 ppm lactic acid, 3) 5 mM glutamic acid. The GABA levels were enhanced in all germinated states of brown rices compared with ungerminated ones, highest in the germinated brown rices by 5 mM glutamic acid solution. Alanine levels were also enhanced significantly in the germinated brown rices. The levels of aspartic acid and glutamic acid were decreased significantly in all the germinated states. The levels of serine decreased during germination in the solutions of water and lactic acid were increased by the germination in the glutamic acid solution. The data show that germination of brown rices by the application of the glutamic acid solution can significantly increase the levels of GABA and can restore the serine level.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.3
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• pp.463-469
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• 2002

The governing equation and force-displacement rotations of a beam-column element on elastic foundation we derived based on variational approach of total potential energy. An exact static and dynamic 4×4 element stiffness matrix of the beam-column element is established via a generalized lineal-eigenvalue problem by introducing 4 displacement parameters and a system of linear algebraic equations with complex matrices. The structure stiffness matrix is established by the conventional direct stiffness method. In addition the F. E. procedure is presented by using Hermitian polynomials as shape function and evaluating the corresponding elastic and geometric stiffness and the mass matrix. In order to verify the efficiency and accuracy of the beam-column element using exact dynamic stiffness matrix, buckling loads and natural frequencies are calculated for the continuous beam structures and the results are compared with F E. solutions.