• Journal of the Korean Chemical Society
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• v.59 no.6
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• pp.508-519
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• 2015

In this study, the pre-service chemistry teachers’ understanding of potential energy curve was investigated. The subjects were 24 junior students and 26 senior students studying chemistry education in a college of education. A concept questionnaire consisted of thought experiments with different initial conditions was developed to survey the pre-service teachers’ conceptions of potential energy curve. The survey results showed that the pre-service chemistry teachers had difficulties to accept the negative values for potential energy and total energy. And they knew the mechanical energy conservation but they could not apply it properly to the thought experiment situations given in the questionnaire. Also they had the knowledge about the direction of force exerted between the two balls, but many of them believed that the balls would stop moving at the bottom of potential energy curve well. In addition, it was discovered that few pre-service teachers could relate the thought experiments to the chemical bonding, the liquefaction of gas, and the molecular vibration.

• Journal of the Korean Chemical Society
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• v.34 no.5
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• pp.389-395
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• 1990

The potential energy of interaction of alkanes C$_1$-C$_5$ and benzene with K$^+$ ion exchanged zeolite L was calculated by applying the atom-atom approximation. For benzene molecule, the atomic charges used for the potential energy calculations were derived from the experimental enthalpy of K+ ion-benzene interaction. The thermodynamic characteristics of the adsorption of the adsorbate molecules (the changes in the internal energy and the isosteric heats at very low coverages) and the potential maps of the adsorbate molecules were determined on basis of the calculated values of potential energy. The calculated values of the isosteric heats agreed fairly well with experimental data for alkanes C$_1$-C$_5$, whereas the calculated isosteric heat for benzene was somewhat greater than that for the experimental value.

• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.15-27
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• 2014

양자화학 (quantum chemistry)을 처음 접했을 때, 이전까지의 고전역학 (classical mechanics)에 익숙한 대다수의 학생들은 양자화학을 받아들이는 데 어려움을 겪는다. 모형계에 양자역학 (quantum mechanics)을 직접 적용하여 봄으로써 생소한 양자 개념에 대한 이해를 도울 수 있다. 본 논문에서는 양자동역학 (quantum dynamics)을 수치적으로 구현하는 계산 프로그램을 모형계에 적용하여 양자 개념을 설명할 수 있는 몇 가지 예를 보이고자 한다. 1 차원 시간의존 슈뢰딩거 방정식 (1-D time-dependent $Schr{\ddot{o}}dinger$ equation)의 해를 얻어 양자동역학을 구현하였으며, 그에 해당하는 고전동역학은 뉴턴 방정식 (Newton's equation)의 해로 얻어졌다. 조화 진동자 퍼텐셜 (harmonic oscillator potential), 모스 진동자 퍼텐셜 (Morse oscillator potential), 이중 우물 퍼텐셜 (double-well potential), 네모 퍼텐셜 장벽 (rectangular potential barrier), 그리고 에카트 퍼텐셜 (Eckart potential)에 대한 계산을 수행하였다. 두 가지 동역학을 비교하기 위하여 계산 결과의 시각화 (visualization)를 이용하고 동역학 특성의 차이를 비교하는 차별화 (differentiation)를 강조한다. 영점에너지 (zero-point energy), 위상어긋남 (dephasing), 터널링 (tunneling), 그리고 반사 (reflection) 현상과 같은 양자동역학의 특징을 고전동역학과 비교함으로써 직관적인 이해를 도울 수 있었다. 이러한 결과는 양자화학에 입문하는 학생들을 대상으로 쓰일 수 있는 효율적인 강의 모델을 제시할 것으로 기대한다.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.903-915
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• 2011

Recently, anaerobic methane production of agricultural waste biomass has received increasing attention. Until now domestic BMP (Biochemical methane potential) studies concerned with agricultural waste biomass have concentrated on the several waste biomass such as livestock manure, food waste, and sewage sludge from WWTP (Waste water treatment plant). Especially, the lack of standardization study of BMP assay method has caused the confused comprehension and interpretation in the comparison of BMP results from various researchers. Germany and USA had established the standard methods, VDI 4630 and ASTM E2170-01, for the analysis of BMP and anaerobic organic degradation, respectively. In this review, BMP was defined in the aspect of organic material represented as COD (Chemical oxygen demand) and VS (Volatile solid), and the influence of several parameters on the methane potential of the feedstock was presented. In the investigation of domestic BMP case studies, BMP results of 18 biomass species generating from agriculture and agro-industry were presented. And BMP results of crop species reported from foreign case studies were presented according to the classification system of crops such as food crop, vegetables, oil seed and specialty crop, orchards, and fodder and energy crop. This review emphasizes the urgent need for characterizing the innumerable kind of biomass by their capability on methane production.

• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.75-88
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• 2014

본 연구에서는 비선형 Poisson-Boltzmann 식의 해를 구할 수 있는 웹 기반 EPBS를 이용하여 이온채널의 전하 분포와 유전률이 이온채널의 이온선택성에 미치는 영향에 대해 알아본다. 모델로 사용한 이온채널은 이온채널과 유사한 구조를 갖는 합성 단백질인 고리형 펩타이드 나노튜브와 자연계에 존재하는 Gramicidin A 이다. 계산 결과로부터 용매인 물과 단백질의 유전율 차이에 의해 이온이 이온채널을 통과할 때 반응장이 생성되며, 이는 이온과 상호작용을 통해 이온 종류에 관계없이 이온 통과를 방해하는 에너지 장벽을 형성함을 알 수 있다. 한편, 두 이온채널 부분 전하, 특히 골격에 존재하는 카르보닐기의 쌍극자 모멘트에 의해 이온채널 내부에는 0 보다 작은 정전기 퍼텐셜이 형성된다. 이온채널 내부의 총 정전기 퍼텐셜은 이온채널의 부분 전하에 의한 정전기 퍼텐셜과 유전률 차이에 의한 반응장의 합으로 나타나며, 계산 결과 0 보다 작은 값을 갖는다. 이로부터 본 연구에서 사용된 두 종류의 이온채널이 양이온에 선택성이 있음을 알 수 있다.

• Journal of the Korean Chemical Society
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• v.51 no.2
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• pp.125-128
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• 2007

In applying Numerov-Cooley method, Excel tool ‘Solver' is used to match those two wave functions propagated inward and outward, respectively. It is numerically confirmed that the same eigenvalue is obtained by using the average of two energy values of each inward and outward wave functions. This method is applied to a NO molecule potential, and we calculated the variations of the average bond distance and tunneling for a given vibrational energy. It is found that the average bond lengths increase proportionately to the vibrational energy, while the tunneling is not so sensitive to the energy changes. Rather substantial amount of tunnel effect is found for every vibrational state.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.264-265
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• 2000

1차원 반도체 구조인 양자 줄(Quantum Wire)은 새로운 물리 현상의 가능성을 보여줄 것으로 기대된다.$^{(1)(2)}$ 이 구조에서 운반자는 2차원 퍼텐셜에 가두어지므로 1차원 퍼텐셜인 양자 우물에 갇힌 운반자 보다 더 많이 양자화가 이루어져 이 운반자의 상태 에너지는 더 쪼개지며, 양자 줄의 상태 밀도는 에너지 준위에 대해 계단 함수가 아닌 변형된 Dirac $\delta$ 함수꼴을 가진다.$^{(3)}$ 그러나, 1차원 반도체 구조인 양자 줄이 나노(nano) 크기 내에서 만들어져야 하므로, 잘 정의된 양자 줄을 만드는 일은 기술상 매우 어려운 일이다. 양자 우물 구조에서 운반자는 결정을 키우는 방향을 따라 나노 크기의 활성 영역 안에 가두어지게 된다. 양자 줄 구조에서의 운반자는 결정 성장 방향뿐만 아니라 수직인 한 방향에서 각각 나노 크기를 갖는 활성 영역에 가두어져야 한다. 여기에서, 결정 성장 방향과 수직으로 활성 영역을 정의하는 것은, 결정 성장 방향과 평행하게 활성 영역을 정의하는 것보다 어려운 일이다. (중략)

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1252-1257
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• 2011

Number of crop residues generated at large amount in agriculture can be utilized as substrate in methane production by anaerobic digestion. Greenhouse vegetable crop cultivation that adopting intensive agricultural system require the heating energy during winter season, meanwhile produce waste biomass source for the methane production. The purpose of this study was to investigate the methane production potential of greenhouse vegetable crop residues and to estimate material and energy yield in greenhouse system. Cucumber, tomato, and paprika as greenhouse vegetable crop were used in this study. Fallen fruit, leaf, and stem residues were collected at harvesting period from the farmhouses (Anseong, Gyeonggi, Korea) adopting an intensive greenhouse cultivation system. Also the amount of fallen vegetables and plant residues, and planting density of each vegetable crop were investigated. Chemical properties of vegetable waste biomass were determined, and theoretical methane potentials were calculated using Buswell's formula from the element analysis data. Also, BMP (Biochemical methane potential) assay was carried out for each vegetable waste biomass in mesophilic temperature ($38^{\circ}C$). Theoretical methane potential ($B_{th}$) and Ultimate methane potential ($B_u$) off stem, leaf, and fallen fruit in vegetable residues showed the range of $0.352{\sim}0.485Nm^3\;kg^{-1}VS_{added}$ and $0.136{\sim}0.354Nm^3\;kg^{-1}VS_{added}$ respectively. The biomass yields of residues of tomato, cucumber, and paprika were 28.3, 30.5, and $21.5Mg\;ha^{-1}$ respectively. The methane yields of tomato, cucumber, and paprika residues showed 645.0, 782.5, and $686.8Nm^3\;ha^{-1}$. Methane yield ($Nm^3\;ha^{-1}$) of crop residue may be highly influenced by biomass yield which is mainly affected by planting density.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.4
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• pp.23-33
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• 2020

Marine algae(Macro algae) are easily bio-degradable, and by-products are available as feed and fertilizer. The biomass of marine algae has higher CO2 absorption capacity than the wood system, and is highly valuable in use due to its fast growth speed and wide cultivation area without special cost for raw material production. In 2018, Marine algae production was 1,722,486ton, such as Saccharina japonica, Undaria pinnatifida and Porphyra tenera, the large amounts of by-products have been generated in the food processing facilities for commercialization. In this study, Saccharina japonica, Undaria pinnatifida were collected in the south coast region and Porphyra tenera was collected in the west coast region. The theoretical methane potential and biochemical methane potential(BMP) were analyzed, and Modified Gompertz model and Parallel first order kinetics model were adopted for the interpretation of the cumulative methane production curves. The theoretical methane potential of Saccharina japonica, Undaria pinnatifida and Porphyra tenera were 0.393, 0.373 and 0.435 N㎥/kg-VS, respectively. BMP obtained by the Modified gompertz model 0.226, 0.227, and 0.241 N㎥/kg-VS for Saccharina japonica, Undaria pinnatifida and Porphyra tenera, respectively. And BMP obtained by the Parallel first order kinetics model were 0.220, 0.243, and 0.240 N㎥/kg-VS for Saccharina japonica, Undaria pinnatifida and Porphyra tenera, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.532-539
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• 2012

This study was carried out to investigate the effect of substrate to inoculum ratio on ultimate methane potential ($B_u$) from piggery wastes. BMP(Biochemical methane potential) assays were executed for the three samples that have different organic characteristics (Filtrate of pig slurry, LF; Thermal hydrolysate of piggery sludge cake, TH; Mixture of LF and TH at the ratio of 4 to 1, Mix), and $B_u$ values obtained from BMP assays were compared with the theoretical methane potential ($B_{th}$) of each samples. While $B_u$ values (0.27, 0.44, and $0.46Nm^3\;Kg^{-1}-VS_{added}$) of TH sample that was pretreated with thermal hydrolysis were below the $B_{th}$ at all S/I ratios (0.1, 0.3, and 0.5), and $B_u$ values of LF (0.64 and $0.53Nm^3\;Kg^{-1}-VS_{added}$ for the S/I ratios of 0.1 and 0.3, respectively) at the lower S/I ratios of 0.1 and 0.3 exceeded the $B_{th}$ values ($0.418Nm^3\;Kg^{-1}-VS_{added}$). And also biodegradability ($B_u/B_{th}$) of LF sample were obtained as 152.07%, 122.67%, and 95.71% at the S/I ratios of 0.1, 0.3, and 0.5, respectively, and unreasonable $B_u/B_{th}$ values were presented at lower S/I ratios of 0.1 and 0.3. $B_u$ and $B_u/B_{th}$ of Mix sample showed a similar tendency with those of LF sample. Therefore, TH sample by thermal hydrolysis pretreatment showed lower anaerobic biodegradability than those of other samples (LF and Mix) and ultimate methane potentials of LF and Mix samples were overestimated in the lower S/I ratio of 0.1 and 0.3.