• 한국환경보건학회지
• /
• 제33권3호
• /
• pp.217-226
• /
• 2007

The purpose of this study is to estimate the emission factor of $non-CO_2$ global warming gases such as $N_2O$ and $CH_4$ by measuring concentrations from stacks of waste incinerators and cement production plants. Based on the established monitoring methods, $N_2O$ concentration measured from stacks in incinerator were between 0.62 and $40.60\;ppm_v$ (ave. $11.50\;ppm_v$). The concentration of $N_2O$ was dependent on the incinerator types. However, the concentrations of $CH_4$ gas were between 2.65 and $5.68\;ppm_v$ (ave. $4.22\;ppm_v$), and did not show the dependency on the incinerator types. In the cement production plant, the concentration ranges of $N_2O$ from the stack were from 6.90 to $10.80\;ppm_v$ (ave. $8.60\;ppm_v$), and $CH_4$ were between 1.80 and $2.20\;ppm_v$ (ave. $2.60\;ppm_v$). Using measured concentrations, the emission amounts of $N_2O$ and $CH_4$ from stacks per year were calculated. The results were is 4.2 ton $N_2O/yr$ in the incinerators, and 53.7 ton $N_2O/yr$ in the cement facilities. The big difference is from the flow rate of flue gas in the cement facilities compared to the incinerators. By the same reason, the $CH_4$ emission amounts in cement plant and incinerator was found to be 339 ton $CO_2/yr$ and 34.1 ton $CO_2/yr$, respectively. Finally, the emission factor of $N_2O$ in the incinerators were calculated using the measured concentration and the amount of incinerated wastes, and was $42.5\sim799.1\;g/ton$ in kiln and stoker type, $11.9\sim79.9\;g/ton$ in stoker type, 90.1 ton/g in rotary kiln type, 174.9 g/ton in fluidized bed type, and 63.8 g/ton in grate type, respectively. Also, the emission factors of $CH_4$ were found to 65.2-91.3 g/ton in kiln/stoker type, 73.9-122 g/ton in stoker type, 109.5 g/ton rotary kiln, and 26.1 g/ton in fluidized bed type. This result indicates that the emission factor in incinerators is strongly dependent on the incinerator types, and matched with result of IPCC (International Panel on Climate Change) guideline.

• 아동학회지
• /
• 제4권
• /
• pp.37-51
• /
• 1983

The purpose of this study was the investigation of theoretical and empirical relationships between Piagetian and psychometric assessments of intelligence. Specifically, the factor structure of Piagetian-type scales, the relationship between Piagetian scales and psychometric intelligence tests, and differences in the factor structure of Piagetian and psychometric assessments of intelligence were studied. The subjects of this stuby were 70 children (35 boys and 35 girls) in the 1st grade of an elementary school in Seoul The Piagetian-type scales and the K-WISC were administered individually, and the General Intelligence Test was administered to groups of children. Statistical analysis of the obtained data consisted of the SPSS Computer program including factor analysis and Pearson's product moment correlation coefficient. The Piagetian-type scales were found to consist of three factors, which accounted for 55 percent of the total common-factor variance. Factor-I was a factor indicating "conservation". Factor-II was a factor indicating "moral judgements". Factor-III was a factor indicating "classification and identity". Correlations between subtests of psychometric tests and Piagetian scales were relatively low or moderate. Relations between IQs assessed by the psychometric tests and Piagetian scales were also relativeyly low or moderate. Eight factors were extracted from the joint factor analysis of psychometric intelligence tests and Piagetian scales, and they accounted for 67 percent of the total common-factor variance. Factors-I, II, III, and V consisted of subtests of psychometric assessments, and Factors-IV, VI, VII and VIII were composed of Piagetian scales. Factor-I was a factor for "reasoning ability based upon language". Factor-II was a factor for "performance ability". Factor-III was a factor for "grouping ability". Factor-IV was a factor for "conservation". Factor-V was a factor indicating "symbol and language usage ability". Factor- VI was a factor indicating "moral judgments". Factor-VII was a factor indicating "length consevation". Factor-VIII was a factor indicating "classification and identity".

• 전기학회논문지P
• /
• 제66권4호
• /
• pp.219-223
• /
• 2017

In this paper, we calculated the losses in the high voltage lines of power distribution system. The losses caused by high voltage lines are calculated using maximum current, resistance, loss factor, and dispersion loss factor. The accurate extraction of these factors are very important to calculate the losses exactly. Thus, the maximum loads are subdivided to regions and calculated monthly for more accurate maximum current calculation. Also, the composite resistance is calculated according to the ratio of the used wire types. In order to calculate the loss factor, the load factors according to the characteristics of each region were calculated. Finally, the losses of the distribution system is calculated by adding the losses by the transformers and the low voltage lines.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2008년도 하계종합학술대회
• /
• pp.499-500
• /
• 2008

In this paper, we design and implement the monolithic power factor correction IC for system power modules using a high voltage(50V) CMOS process. The power factor correction IC is designed for power applications, such as refrigerator, air-conditioner, etc. It includes low voltage logic, 5V regulator, analog control circuit, high-voltage high current output drivers, and several protection circuits. And also, the designed IC has standby detection function which detects the output power of the converter stage and generates system down signal when load device is under the standby condition. The simulation and experimental results show that the designed IC acts properly as power factor correction IC with efficient protective functions.

• Steel and Composite Structures
• /
• 제14권6호
• /
• pp.621-636
• /
• 2013

Response modification factor is one of the seismic design parameters to consider nonlinear performance of building structures during strong earthquake, in conformity with the point that many seismic design codes led to reduce the loads. In the present paper it's tried to evaluate the response modification factors of dual moment resistant frame with buckling restrained braced (BRB). Since, the response modification factor depends on ductility and overstrength; the nonlinear static analysis, nonlinear dynamic analysis and linear dynamic analysis have been done on building models including multi-floors and different brace configurations (chevron V, invert V, diagonal and X bracing). The response modification factor for each of the BRBF dual systems has been determined separately, and the tentative value of 10.47 has been suggested for allowable stress design method. It is also included that the ductility, overstrength and response modification factors for all of the models were decreased when the height of the building was increased.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제3권1호
• /
• pp.1-12
• /
• 2003

This paper describes a study on the abnormal behavior of the electrical characteristics of the (n)GaAs/Ti/Pt/Au Schottky contacts prepared by the two techniques of electron beam deposition and rf sputtering and after an annealing treatment. The samples were characterized by I-V and C-V measurements carried out over the temperature range of 150 - 350 K both in the as prepared state and after a 300 C, 30 min. anneal step. The variation of ideality factor with forward bias, the variation of ideality factor and barrier height with temperature and the difference between the capacitance barrier and current barrier show the presence of a thin interfacial oxide layer along with barrier height inhomogenieties at the metal/semiconductor interface. This barrier height inhomogeneity model also explains the lower barrier height for the sputtered samples to be due to the presence of low barrier height patches produced because of high plasma energy. After the annealing step the contacts prepared by electron beam have the highest typical current barrier height of 0.85 eV and capacitance barrier height of 0.86 eV whereas those prepared by sputtering (at the highest power studied) have the lowest typical current barrier height of 0.67 eV and capacitance barrier height of 0.78 eV.

• 대한기계학회논문집A
• /
• 제27권1호
• /
• pp.66-76
• /
• 2003

The arbitrary V-notched crack problem is considered. The general expressions for the stress components on this problem are obtained as explicit series forms composed of independent unknown coefficients which are denoted by coefficients of eigenvector. For this results eigenvalue equation is performed first through introducing complex stress functions and applying the traction free boundary conditions. Next solving this equation, eigenvalues and corresponding eigenvectors are obtained respectively, and finally inserting these results into stress components, the general equations are obtained. These results are also shown to be applicable to the symmetric V-notched crack or straight crack. It can be shown that this solutions are composed of the linear combination of Mode I and Mode II solutions which are obtained from different characteristic equations, respectively. Through performing asymptotic analysis for stresses, the stress intensity factor is given as a closed form equipped with the unknown coefficients of eigenvector. In order to calculate the unknown coefficients. based on these general explicit equations, numerical programming using the overdetermined boundary collocation method which is algorithmed originally by Carpenter is also worked out. As this programming requires the input data, the commercial FE analysis for stresses is performed. From this study, for some V-notched problems, unknown coefficients can be calculated numerically and also fracture parameters are determined.

• 동아시아식생활학회지
• /
• 제4권3호
• /
• pp.59-65
• /
• 1994

이 실험에서는 소의 유즙에 있는 성장인자를 세포배양을 통해 확인하고 크로마토그래피를 사용하여 분리 정제하였다. 5%의 우유를 포함하는 배지를 FBS(fetal bovine serum)를 포함한 배지와 비교했을때 Africal green monkey kidney cell의 성장 촉진 효과가 비슷하게 나타났으며, 우유의 성장인자를 분리 정제한 결과 FBS배지에서보다 2,000배 이상의 성장 촉진 효과가 나타났다. 이 성장인자는 hydrophobic column(phenyl-sepharose)과 gel-filtration column(sephadex G-100)을 사용하여 분리했으며 그 결과 milk-deriven growth factor는 phenyl-sepharose에서 50% ethylene glycol step에서 용출되므로 hydrophobic protein임이 증명되었고 size exclusion column chromatography로 부터 분자량이 100,000-15,0000 범위의 고분자 물질임이 밝혀졌다. 또한 우유의 성장인자는 매우 다양하며 그중 본 실험으로부터 정제된 물질이 주요 성장인자로 밝혀졌다.

• 한국결정성장학회지
• /
• 제22권1호
• /
• pp.51-56
• /
• 2012

본 연구에서는 출발원료로 ${\sigma}$-VCo 금속간화합물과 $V_{50}Co_{50}$ 혼합분말을 각각 사용하여 기계적 합금화에 따른 비정질화 가능성을 조사하였다. X선 회절에 의해 얻어진 전구조인자 S(Q) 및 동경분포함수 RDF(r)의 결과로부터 볼밀링이 진행됨에 따라 비정질상의 구조적 특징이 분명히 관찰되었다. 120시간 MA 처리에 의하여 두 경우 모두에서 비정질상이 생성됨을 알 수 있었다. 60시간 동안 MA 처리한 $V_{50}Co_{50}$ 분말시료의 열분석 에서는 약 $600^{\circ}C$에 비정질상의 결정화에 의한 발열 peak가 관찰되었다. X선 회절법에 의해 얻어진 전구조인자 및 동경분포함수의 분석으로부터 MA 시간에 따라 출발 결정상은 비정질상의 특징적인 원자구조로 서서히 변화함을 알 수 있었다.

• 전력전자학회논문지
• /
• 제5권5호
• /
• pp.508-514
• /
• 2000

본 논문에서는 역률개선용 단일 스위치 부스트 플라이백 결합형 ZCS quasi-resonant converter(QRC)를 제안한다. 제안된 컨버터는 입력전류를 불연속 모드로 동작시켜 역률을 개선하며 입력전류의 zero-crossing-point에서의 왜곡을 개선함으로써 고조파를 감소시켜 역률을 향상시켰으며 좋은 출력전압의 regulation 성능을 가지고 있다. 그리고 체계적인 설계를 위하여 설계식을 제안하였으며 제안된 설계식을 통하여 프로토타입 컨버터를 설계하였다. 실험결과 효율은 약 86%, 역률은 약 0.985이상을 얻었다. 따라서 본 컨버터는 스위칭 주파수가 수백kHz이상이고 높은 regulation성능을 요구하는 낮은 전압의 소용량 컨버터에 적합하다.