• 한국도로학회논문집
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• 제13권3호
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• pp.111-119
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• 2011

본 연구에서는 실시간으로 개별 차량에 대한 소음 예측 시뮬레이션을 통해 매 순간 소음지도와 Lmax, Lmin 등을 얻을 수 있는 소음 예측 모델을 제시하였다. GIS 지형처리 기법을 이용해 공간 모델 처리 기법을 바탕으로 실시간 교통소음예측 시스템 모델을 제안하고, 객체지향기법을 이용해 개발하였다. 실시간 소음 시뮬레이션 모델을 이용하여 교통 흐름의 변화에 따라 소음레벨, 소음지도 변화, Lmin, Lmax값을 한눈에 파악하거나 비교할 수 있다. 현장에서 수행한 소음측정치와 예측치를 비교한 결과, 대부분 거리에서 Leq는 2~3db, Lmax는 3~4db 이내의 차이를 나타내어 소음예측의 신뢰성이 양호함을 확인할 수 있었다. 개발된 시스템을 이용해 민감도 분석을 수행한 결과, 대형차 비율, 차량 속도, 방음벽 높이에 따라 소음레벨의 차이를 보였고, 특히 방음벽 높이는 Leq나 Lmin보다 Lmax에 큰 영향을 미치는 것을 알 수 있었다.

• 한국지반신소재학회논문집
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• 제12권4호
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• pp.87-98
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• 2013

본 연구는 석탄회의 상대밀도를 40%, 60%, 80%, 95%로 각각 변화시켜 등방압축팽창시험과 구속압력을 달리한 배수삼축시험을 하였다. 그리고 이 시험자료를 이용하여 Lade의 단일항복면 구성모델의 토질매개변수의 변화 특성을 알아보았다. 그 결과 탄성성분을 나타내는 토질매개변수 Kur과 n은 상대밀도의 변화에 따른 영향이 미소하고 파괴규준, 경화함수, 소성포텐셜에 관련된 토질매개변수는 상대밀도의 증가에 따라 선형적인 증 감현상을 보이고 있다. 그리고 항복함수에 관련된 토질매개변수 h와 ${\alpha}$는 상대밀도에 따른 변화가 미세하고 파괴규준에 관련한 토질매개변수와 관련성이 매우 높아 파괴규준, ${\eta}_1$에 관한 식으로 대체할 수 있으며, 이 식을 이용하여 수치해석한 결과 양호하게 예측하고 있다.

• Bulletin of the Korean Chemical Society
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• 제33권9호
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• pp.2971-2975
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• 2012

Second-order rate constants $k_N$ have been measured spectrophotometrically for nucleophilic substitution reactions of t-butyl 4-pyridyl carbonate 8 with a series of alicyclic secondary amines in $H_2O$ at $25.0{\pm}0.1^{\circ}C$. The Br${\emptyset}$nsted-type plot for the reactions of 8 is linear with ${\beta}_{nuc}$ = 0.84. The ${\beta}_{nuc}$ value obtained for the reactions of 8 is much larger than that reported for the corresponding reactions of t-butyl 2-pyridyl carbonate 6 (i.e., ${\beta}_{nuc}$ = 0.44), which was proposed to proceed through a forced concerted mechanism. Thus, the aminolysis of 8 has been concluded to proceed through a stepwise mechanism with a zwitterionic tetrahedral intermediate $T^{\pm}$, in which expulsion of the leaving-group from $T^{\pm}$ occurs at the rate-determining step (RDS). In contrast, aminolysis of benzyl 4-pyridyl carbonate 7 has been reported to proceed through two intermediates, $T^{\pm}$ and its deprotonated form $T^-$ on the basis of the fact that the plots of pseudo-first-order rate constant $k_{obsd}$ vs. amine concentration curve upward. The current study has demonstrated convincingly that the nature of the leaving and nonleaving groups governs the reaction mechanism. The contrasting reaction mechanisms have been rationalized in terms of an intramolecular H-bonding interaction, steric acceleration, and steric inhibition.

• 대한화학회지
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• 제13권2호
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• pp.121-129
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• 1969

n-Alkylamine hydrochlorides $C_nH_{2n+1}NH_3CI$에서 n=0에서 n=4 까지 이르는 低分子量 同族體의 apparent molal volume {\phi}\nu$ 및 partial molal volume $V^{\circ}$을 30$^{\circ}C$水溶液에서 測定하엿다 아민산의 濃度는 0.01M에서 0.3M까지 , 密度測定은 浮力法(Float method)를 適用하여 少數點 以下 5位까지 取하였다. 實驗結果 同族體의 分子量이 一定量 $CH_2$식 增加함에 따라 $V^{\circ}$값이 規則的인 差로서 增加한다는 事實이 觀測되었다. 또한 濃度增加함에 따른 {\phi}\nu$ 變化는 共通的으로 直選的이고 limiting slope는 positive이며 比較的 理論値에 가까왔다. 共通anion인 鹽素이온 $CI^-$의 partial molal volume, $V^{\circ}$$CI^-$은 18.6ml $mole^{-1}$으로 他硏究者들의 date와 大體的으로 一致하였다. {\phi}{\nu}$ 값의 變化로 보아 이온의 hydrophobic effect와 change effect는 거의 競合狀態이나 charge effect 곧 electrostriction effect가 優勢를 보였다.

• 건축역사연구
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• 제7권3호
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• pp.53-66
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• 1998

In the meantime, the study of traditional and contemporary house had been produced so many achievements in korea, but modern house is yet to be solved, Accordingly, It is necessary to develop and present the basic research data in order to build up an objective study for urban house in the modern age(1910-1945), Following to a study on the foreigner's house in grid-type settlement of Open Ports, in this research is to investigate and analyze modern houses of urban areas in korean inland, and then clarify types and changes of them. In the first year($1995{\sim}96$), the modern houses of Central Inland Districts(arrounding river Kumgang)-Kunsan kanggyong Puyo Kongju Pugang Chongju were investigated by the layout of room, the construction and materials, the design and style, etc. In the second year($1996{\sim}97$), the modern houses of Open Market(開市場)-Seoul Taegu Kwangju Taejon Chonju were conducted to investigate as above. The traditional house transformed by differentiation and addition of room(kan), the various types were respectively adopted for the korean reforming and western cultural house. In the layout of room, the types of plan were gradually concentrated from the single wings of korean traditional house. The korean traditional house was later improved through the introduction of entrance, corridor, and internal toilet/bathroom. But the korean under-floor heating system(andal) and a series of three rooms had been entirely maintained, composed of master bedroom/living room(daechung)/room. And the traditional town house with shop and storage, being built closely to each other and walled up both sides, it had taken gradually the extensive characteristics in itself. By the displacement of shop/dwelling/ storage. the various types were respectively adopted for the separated, multi-storied, and complex type. The type of them was gradually changed to the narrow and linear form. And so with the stockpile of fundamental datas about modern houses in korean urban areas, we expect these results contribute to the knowledge of the spatial characteristics of urban house at present which are required to the understanding of transition as well as types.

• 분석과학
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• 제29권1호
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• pp.35-42
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• 2016

A new nano-composite carbon ink for the development of disposable dopamine (DA) biosensors based on screen-printed carbon electrodes (SPCEs) is introduced. The method developed uses SPCEs coupled with a tyrosinase modified nano-composite carbon ink. The ink was prepared by an “in-house” procedure with reduced graphene oxide (rGO), Pt nanoparticles (PtNP), and carbon materials such as carbon black and graphite. The rGO-PtNP carbon composite ink was used to print the working electrodes of the SPCEs and the reference counter electrodes were printed by using a commercial Ag/AgCl ink. After the construction of nano-composite SPCEs, tyrosinase was immobilized onto the working electrodes by using a biocompatible matrix, chitosan. The composite of nano-materials was characterized by X-ray photoelectron spectroscopy (XPS) and the performance characteristics of the sensors were evaluated by using voltammetric and amperometric techniques. The cyclic voltammetry results indicated that the sensors prepared with the rGO-PtNP-carbon composite ink revealed a significant improvement in electro-catalytic activity to DA compared with the results obtained from bare or only PtNP embedded carbon inks. Optimum experimental parameters such as pH and operating potential were evaluated and calibration curves for dopamine were constructed with the results obtained from a series of amperometric detections at −0.1 V vs. Ag/AgCl. The limit of detection was found to be 14 nM in a linear range of 10 nM to 100 µM of DA, and the sensor’s sensitivity was calculated to be 0.4 µAµM⁻¹cm⁻².

• 분석과학
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• 제16권4호
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• pp.320-324
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• 2003

산성의약품의 선택성 액체막 전극을 전기활성물질로서 di-2-pyridyl ketone (DPK)-금속-산성의약품간의 삼성분착물로 제조하였다. 금속이온은 $Fe^{2+}$, $Co^{2+}$, $Ni^{2+}$, $Cu^{2+}$ 등을 사용하였고, 가소제는 니트로페닐에텔계를 사용하였다. 메페남산 선택성 막 전극은 pH 8.9의 붕산 완충용액중에서 그리고 이부프로펜 선택성 막 전극은 pH 7.0의 인산 완충용액 중에서 각각 $5{\times}10^{-5}{\sim}10^{-3}mol/L$ 농도에서 검정선이 얻어졌다. 메페남산 및 이부프로펜 표준품 일정량 첨가에 의한 회수율을 측정한 결과는 99.0%와 98.4%이었고 상대표준편차는 각각 2.4%와 2.6%이었다.

• 분석과학
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• 제33권3호
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• pp.125-133
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• 2020

Methylisothiazolinone (MIT) and chloromethylisothiazolinone (CMIT) cause allergic contact dermatitis and are banned cosmetics ingredients, except in rinse-off products. However, their presence has been detected in cosmetics. We report a UPLC-tandem MS/MS screening method for their simultaneous determination in cosmetics. To facilitate extraction from various matrices, pretreatment methods were developed for each sample type. The method was optimized through a series of assessments, including specificity, LOD, LOQ, linearity, recovery, stability, precision, and accuracy. The LODs and LOQs for MIT ranged from 0.054 and 0.163 ㎍ mL^-1 whereas those for CMIT ranged from 0.040 and 0.119 ㎍ mL^-1. The linear correlation coefficients (r²) were higher than 0.999. Relative standard deviations (RSDs) for both intra- and inter-day measurements ranged from 0.3 ~ 13.6 %. Recoveries at three different concentrations were within 87.9 ~ 118.9 %. The RSD for stability measurements of spiked samples was within 7 %. These results confirm the suitability of the developed method for the simultaneous quantitation of MIT and CMIT in cosmetics. Samples of 320 color cosmetics, including eyeshadows, solid lipsticks, liquid lipsticks, and nail polishes were analyzed using the developed method, and two of them were found to contain both MIT and CMIT and one of them was found to contain only MIT. This data and the method will aid the regulation of ingredients used in cosmetics.

• 한국지반공학회논문집
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• 제32권7호
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• pp.35-45
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• 2016

해양구조물을 지지하기 위해 사용되는 버킷기초를 설계하는데 있어 수직지지력을 정확하게 예측하는 것은 중요하다. 사질토 또는 점성토 지반에 설치된 버킷기초의 수직지지력에 대한 실험적, 이론적 연구가 많이 수행되었지만, 실제와 같은 다층지반에서의 산정방법은 명확하게 제시되지 않았다. 본 연구에서는 2차원 축대칭 유한요소해석을 수행하여 점성토 지반 위의 사질토 층에 설치된 버킷기초의 수직지지력을 산정하였다. 사질토의 마찰각, 점성토의 비배수전단강도, 사질토 층 두께, 기초의 장경비가 다양한 조건에 대하여 매개변수 해석을 수행하였으며, 이들의 영향에 따른 지반의 파괴 메커니즘 차이를 분석하였다. 최종적으로 수치해석을 수행하여 얻어진 극한지지력의 결과를 바탕으로 버킷기초 설계에 사용할 수 있는 지지력 산정 차트를 제시하였다. 또한 설계차트에 직접 제시되어 있지 않은 조건에 대해서는 차트에 제시된 값에 선형보간법을 적용하여 버킷기초의 선단지지력을 예측할 수 있는 것으로 나타났다.

• Smart Structures and Systems
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• 제19권2호
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• pp.163-179
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• 2017

The axisymmetric buckling delamination of the Piezoelectric/Metal/Piezoelectric (PZT/Metal/PZT) sandwich circular plate with interface penny-shaped cracks is investigated. The case is considered where open-circuit conditions with respect to the electrical displacement on the upper and lower surfaces, and short-circuit conditions with respect to the electrical potential on the lateral surface of the face layers are satisfied. It is assumed that the edge surfaces of the cracks have an infinitesimal rotationally symmetric initial imperfection and the development of this imperfection with rotationally symmetric compressive forces acting on the lateral surface of the plate is studied by employing the exact geometrically non-linear field equations and relations of electro-elasticity for piezoelectric materials. The sought values are presented in the power series form with respect to the small parameter which characterizes the degree of the initial imperfection. The zeroth and first approximations are used for investigation of stability loss and buckling delamination problems. It is established that the equations and relations related to the first approximation coincide with the corresponding ones of the three-dimensional linearized theory of stability of electro-elasticity for piezoelectric materials. The quantities related to the zeroth approximation are determined analytically, however the quantities related to the first approximation are determined numerically by employing Finite Element Method (FEM). Numerical results on the critical radial stresses acting in the layers of the plate are presented and discussed. In particular, it is established that the piezoelectricity of the face layer material causes an increase (a decrease) in the values of the critical compressive stress acting in the face (core) layer.