• 대한화학회지
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• 제53권6호
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• pp.640-652
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• 2009

캘릭스[n]아렌 (1-4)의 다양한 이형체들에 대한 구조들이 DFT B3LYP/6-31+G(d,p) 와 mPW1PW91/ 6-31+G(d,p) (hybrid HF-DF) 계산 방법들에 의하여 최적화 되었다. 모든 캘릭스[n]아렌 (1-4)의 다양한 이형체들 중에서, 수소결합들의 영향으로, cone 이형체가 가장 안정하였다. 그러나, 이형체들의 상대적인 안정성은 다음과 같이 서로 달랐다. 1. t-부틸캘릭스[4]아렌(1): cone > partial-cone > 1,2-alternate > 1,3-alternate. 2. t-부틸캘릭스[5]아렌(2): cone > 1,2-alternate > partial-cone > 1,3-alternate. 3. 탈부틸화된 캘릭스[6]아렌(3): cone(pinched) > partial-cone > cone(winged) ~ 1,2-alternate - 1,2,3-alternate > 1,4-alternate > 1,3-alternate > 1,3,5-alternate. 4. t-부틸캘릭스[6]아렌(4): cone(pinched) > 1,2-alternate > cone(winged) > 1,4-alternate - partial-cone > 1,2,3-alternate > 1,3,5-alternate > 1,3-alternate. 분자 내부의 수소결합의 개수와 강도들이 캘릭스[n]아렌의 다양한 이형체들의 상대적인 안정성에 가장 영향을 많이 미치는 인자들이었다. 두 가지 서로 다른 계산방법들 (B3LYP과 mPW1PW91)에 대한 여러 가지 이형체들에서의 수소결합 길이들이 비교되었다.

• Coupled systems mechanics
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• 제2권1호
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• pp.23-51
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• 2013

An analytical algorithm for the estimation of the resistance forces exerted on the dipper of a cable shovel and the specific energy consumed in the cutting-loading process is presented. Forces due to payload and to cutting of geomaterials under given initial conditions, cutting trajectory of the bucket, bucket's design, and geomaterial properties are analytically computed. The excavation process has been modeled by means of a kinematical shovel model, as well as of dynamic payload and cutting resistance models. For the calculation of the cutting forces, a logsandwich passive failure mechanism of the geomaterial is considered, as has been found by considering that a slip surface propagates like a mixed mode crack. Subsequently, the Upper-Bound theorem of Limit Analysis Theory is applied for the approximate calculation of the maximum reacting forces exerted on the dipper of the cable shovel. This algorithm has been implemented into an Excel$^{TM}$ spreadsheet to facilitate user-friendly, "transparent" calculations and built-in data analysis techniques. Its use is demonstrated with a realistic application of a medium-sized shovel. It was found, among others, that the specific energy of cutting exhibits a size effect, such that it decreases as the (-1)-power of the cutting depth for the considered example application.

• 한국토양비료학회지
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• 제39권5호
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• pp.274-279
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• 2006

FAO에서는 세계의 증발산량을 동일한 방식으로 산정하기 위해 다양한 형태의 모형들을 소개하고 각국이 적용하도록 권고해왔으며 최근에는 Penman-Monteith(PM) 모형을 증발산 산정에 이용하도록 하고 있다. 따라서, 본 연구에서는 다양한 기상요소와 작물 생장을 고려해 시간별 또는 일별로 증발산량의 정량화가 가능한 FAO PM 모형의 증발산량 계산에 이용되고 있는 다양한 기상요소들을 평가하고자 하였다. 측정 장비를 통해 얻어진 순복사량과 지중열류량, 수증기압, 풍속, 기온 등의 기상요소를 PM 모형계산식 (2)부터 (9)까지의 과정에 적용해 보았다. 초지에서 측정한 알베도의 평균값은 0.20이고 최대는 0.23, 최소는 0.12를 나타내 평균값은 FAO PM에서 잔디의 반사율인 0.23보다 다소 낮은 값을 보였다. 측정 알베도에 의한 순복사량과 잔디의 알베도(0.23)를 이용한 순 복사량을 비교해보면 결정계수는 0.97과 0.95, 표준오차는 0.74와 0.80이었으나 예측 값은 실제 값에 직선의 상관을 이루며 회귀식의 유의성이 인정되었다. 지중열류량의 FAO PM에서의 영향정도를 판단하기 위해 지중 5cm 깊이에서 측정한 지중열류($G_{5cm}$)와 지표면 보정식에 의해 보정된 지중열류량($G_{0cm}$)을 지중열류량이 0일 때의 (G=0) RET 값과 비교하연 G=0일 때의 RET는 $G_{5cm}$에서의 RET보다 3-5 mm 범위에서 약간 크게 예측하고, $G_{0cm}$에서의 RET 보다는 5mm 이상에서 약간 작게 예측하나 두 경우 모두 거의 일치하는 경향이었다. 측정된 순복사와 $G_{0cm}$에 의한 RET를 지중열류량을 모두 0으로 했을 때 측정 순복사에 의해 얻어진 RET(I), 측정된 에 의해 예측된 순복사로 계산한 RET(II), ${\alpha}=0.23$을 대입하여 구한 순복사로 계산한 RET(III)와 비교했을 때 I, II, III의 결정계수와 표준오차 및 p값은 측정 순복사량과 $G_{0cm}$에 의한 RET를 비교적 잘 설명하고 있으나, II와 III처럼 알베도 값과 일사량 및 식 (3)~(9)를 이용해 얻어진 순복사량을 이용해 RET를 계산할 때는 Table1에 나타나 있는 회귀식을 이용해 이를 보정해주어야 RET 계산의 오차를 줄일 수 있을 것이다. 이상의 결과를 종합하면 FAO PM 모형에 이용되는 기상요소들을 측정할 수 없을 때는 지표면 복사율을 나타내는 지중열류 값은 0으로 산정하고 순복사량 예측 값과 잔디의 지표면 반사율 또는 알려진 작물의 반사율을 이용해 RET를 계산하는 것이 가능할 것이다.

• 한국가정과교육학회지
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• 제6권1호
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• pp.7-33
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• 1994

The purpose of this study is to revise the food composition table based on commonly consumed single serving size of cooked food so the people can easily use the table in each meal. With this revised food composition table, everybody can easily calculate how much they eat, and plan the menu according to how much they need, so hopely contribute to reduce the leftover foods. Eighty-nine kinds of prepared food dishes were selected based on 13 home economics text books of the junior and high schools. The results are summarized as follows: Cooked food dishes comprise various kinds of rice dishes, korean style soups and stewes, fried, roasted or steamed fishes, vegetables and meats, and desserts. Single serving size of cooked food dishes are presented below: 1) rise : 180∼250g, 1(1/3)∼1(2/3)cup 2)soup:320∼400g, 1(1/2)∼2cup 3)pan fried fish or vegetable : 40∼70g 4)deep fried vegetable, fish or meat; 60g 5)kimchi :50g Single serving size of all other dishes are presented based upon the most commonly consumed amount in each meal by adult male.

• Journal of Advanced Marine Engineering and Technology
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• 제5권1호
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• pp.28-33
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• 1981

The characteristics of typical 35 kinds of domestic anthracites among 155 kinds are studied to find the calculation formula for the required quantity of air and the combustion gas quantity. 1) The author's calculation formulae are as follows: ${A_0}={\frac{1, 000}{1, 064}}{H_1}+0.086(Nm^3/kg)$ ${G_0}={\frac{1, 000}{1, 110}}{H_1}+0.234(Nm^3/kg)$(1) Theoretically required quantity of air (2) Theoretical quantity of combustion gas 2) Theoretical quantity of air in combustion of domestic anthracite is always estimated more with Rosin's formula than author's one in the typical domestic anthracites which have the lower calorific value between 3, 000-8, 000 Kcal/kg and the difference of the calculated quantity of air becomes small, as the calorific value increases. 3) Theoretical quantity of combustion gas is estimated more by author's formula than by Rosin's one with the domestic anthracites which have more calorific value than 6, 700 Kcal/kg and is estimated less in the under range of the above calorific value. 4) Theoretical quantity of required air and quantity of combustion gas of domestic anthracite show ${\pm}$4% difference by Rosin's formulae in comparison with results of actual analysis, and about ${\pm}$1.5% by the author's one.

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2352-2358
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• 2012

A high-nitrogen energetic salt, 1-amino-1-hydrazino-2,2-dinitroethylene guanidine salt [G(AHDNE)], was synthesized by reacting of 1-amino-1-hydrazino-2,2-dinitroethylene (AHDNE) and guanidine hydrochloride in sodium hydroxide aqueous solution. The theoretical investigation on G(AHDNE) was carried out by B3LYP/$6-311+G^*$ method. The thermal behaviors of G(AHDNE) were studied with DSC and TG-DTG methods, and the result presents an intense exothermic decomposition process. The enthalpy, apparent activation energy and pre-exponential constant of the process are $-1060J\;g^{-1}$, $148.7kJ\;mol^{-1}$ and $10^{15.90}s^{-1}$, respectively. The critical temperature of thermal explosion of G(AHDNE) is $152.63^{\circ}C$. The specific heat capacity of G(AHDNE) was studied with micro-DSC method and theoretical calculation method, and the molar heat capacity is $314.69J\;mol^{-1}K^{-1}$ at 298.15 K. Adiabatic time-to-explosion of G(AHDNE) was calculated to be a certain value between 60-72 s. The detonation velocity and detonation pressure were also estimated. G(AHDNE) presents good performances.

• 대한조선학회지
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• 제13권1호
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• pp.1-9
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• 1976

Using the computer programs for calculation of natural vibrations of ship's hull developed by the authors et al., an investigation into influences of various parameters on the accuracy of calculation was done through example calculations of a 30,000 DWT petroleum products carrier M/S Sweet Brier built by Korea Shipbuilding and Engineering Corporation. The methodical principles employed for the computer program development are as follows; (a) the ship system is reduced to an equivalent discrete elements system conforming to Myklestad-Prohl model, (b) the problem formulation is of transfer matrix method, and (c) to obtain solutions an extended $G\ddot{u}mbel's$ initial value method is introduced. The scope of the investigation is influences of number of discrete elements, choice of significant system parameters such as rotary inertia, bending stiffness and shear stiffness, and simplification of distributions of added mass and stiffness as trapezoidal ones referred to those of midship section on the calculation accuracy. From the investigation the followings are found out; (1) To obtain good results for the modes up to the seven-noded thirty or more divisions of the hull is desirable. For fundamental mode fifteen divisions may give fairly good results. (2) The influence of rotary inertia is negligibly small at least for the modes up to the 5- or 6- noded. (3) In the case of assuming either bending modes or shear modes the calculation results in considerably higher frequencies as compared with those based on Timoshenko beam theory. However, the calculation base on the slender beam theory surprisingly gives frequencies within 10% error for fundamental modes. (4) It is proved that to simplify distributions of added mass and stiffness as trapezoidal ones referred to those of midship section is a promising approach for the prediction of natural frequencies at preliminary design stage; provided good accumulation of data from similar type ships, we may expect to obtain natural frequencies within 5% error.

• Asian Journal of Atmospheric Environment
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• 제7권3호
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• pp.161-168
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• 2013

In this study, an investigation was conducted to assess the washout mechanism of Asian dust particles through both laboratory-scale experiment and model calculation. To artificially simulate Asian dust particle, $CaCO_3$ particles were generated inside an experimental chamber. They were then scavenged by the artificial rain drops. The abundant $CaCO_3$ particles scavenged on a rain drop were successively identified by SEM observation. The concentrations of Ca in residual $CaCO_3$ particles on individual droplet were quantified by PIXE analysis. There was a tendency toward a high accumulation of Ca on a relatively small drop (e.g., <1.0 mm diameter). It is thus suggested that smaller rain drops can effectively scavenge a significant amount of Asian dust particles in ambient atmosphere. The numerical estimation can account for 92.1% and 83.2% of Ca that were measured in small (<1.0 mm diameter) and large (>2.0 mm diameter) size drops, respectively.

• Bulletin of the Korean Chemical Society
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• 제15권2호
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• pp.139-145
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• 1994

The DOS, COOP and O 1s binding energy are calculated for Ni24(100) model surface with oxygen adsorbed on it. The calculation is made with PC/386 using the program obtained by converting EHMACC(VAX version) into PC version. The calculation shows the dissociative adsorption of oxygen molecule, of which the main cause is attributed to the transfer of the $d{\pi}$ and $d{\delta}$ electrons of Ni to the antibonding $1{\pi}_g$ of oxygen molecule. The O ls shift on the adsorption is calculated using the valence potential method, and the results agree fairly good with the experimental values.

• 한국염색가공학회지
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• 제19권4호
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• pp.18-25
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• 2007

Kinetics and mechanism for alkaline hydrolysis of C. I. Disperse Green 9(G-9) of dinitrothiophene disperse dye were investigated. As soon as G-9 contacted with alkali, instant and continuous decreases of color strength of G-9 followed with increasing time. The hydrolysis rate of G-9 increased with increasing alkali, and it was found that alkali appeared first order dependence. The observed rate constants obtained from hydrolysis of various amount of dye were similar values, and calculation of initial rates showed that G-9 hydrolyzed by first order reaction for dye. Therefore it was confirmed that the overall reaction was second order, $SN_2$ of nucleophilic substitution reaction. Increasing temperature enhanced the hydrolysis of G-9. From the results of hydrolysis performed at various temperatures, it was obtained that activation energy(Ea) was 12.6 kcal/mole, enthalpy of reaction(${\triangle}H$) was 12.0 kcal/mole, and entropy of reaction(${\triangle}S$) was $29.8J/mol{\cdot}K$.