• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.224-231
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• 2010

In GvdW EOS, a recently presented paper, shows that the characteristic status for spherical non-linear particle, of which the mutual behavior is known to be vdWf(van der Waals force) only, could be described well enough in the critical region. However, in current papers, analysis has not been done on GvdW about whether it is accurate or not, even for the particles in the linear form or those with the additional mutual behavior such as static-electricity, so there's some argument about the wide use of that. Therefore, in this paper, for the simulation in the critical region of Normal-alkane group(R=methane, ethane, propane, butane) which are the particles that has a linear charateristic and Normal-amine group($RNH_2$, R=methyl-, ethyl-, propyl-amine) where static-electricity is extremely shown, GvdW parameter values about these particles are defined, and based on this simulation, we compared results to the current EOS presented recently, and analyzed them. Through the simulation, it was shown that in case of Normal-alkane group and Normal-amine group molecules, GvdW presents an accurate critical region characteristic which is far more close to the measurement compared to current EOSs. Especially for butane with big amount in molecules, we found out that only GvdW EOS can reach close enough to the critical point.

• Journal of the Society of Disaster Information
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• v.9 no.3
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• pp.249-258
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• 2013

Recieved Mar. 06, 2013 Revised Mar. 29, 2013 Accepted Sep. 11, 2013In this study, we evaluated the method performance and the optimum sample injection method of the portable GC/MS(HAPSITE) which were designed to operate on scene of chemical accidents. Chemicals used for performance test were vinyl chloride(VC), methyl chloride(MC), benzene(Bz), toluene(Tol). CRM(Certified Reference Material) Manufactured by KRISS(Korea Research Institute of Standards and Science) was used as the standard gas. The results showed that 1) Among three sample injection methods(Cylinder, Silico canister, and Bag), bag was identified as the most appropriate sample injection method. Bag material and capacity did not significantly affect the results. The most ideal reproducibility occurred at the 2-minute point of the purge time in the loop and tenax methods. 2) Performance evaluation of HAPSITE was conducted. Evaluation items were reproducibility, linearity, method detection limit, etc. Tenax concentration method was appropriate for larger molecules and Carbopack concentration method was suitable for smaller molecules.

• Journal of the Korean Institute of Gas
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• v.24 no.1
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• pp.17-22
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• 2020

Light Naphtha is distillated from crude oil unit and separated into the methane, ethylene and propylene by boiling point difference in sequence. This separation is conducted using a series of binary-like columns. This separation method is known that the energy consumed in the reboiler is used to separate the heaviest components and most of this energy is discarded as vapor condensation in the overhead cooler. In this study, the first two columns of the separation process are replaced with the Petlyuk column. A structural design was exercised by the stage computation with ideal tray efficiency in equilibrium condition. Compared with the performance of a conventional system of 3-column model, The design outcome shows that the procedure is simple and efficient because the composition of the liquid component in the column tray was designed to be similar to the equilibrium distillation curve. The performance of the new process indicates that an energy saving of 12.1% is obtained and the cost savings of 44 million won per day based on gross domestic product is reduced under same total number of trays and the initial investment cost is saved.

• Journal of Biomedical Engineering Research
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• v.24 no.4
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• pp.319-328
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• 2003

The purpose of this paper is to develop a medical laser system using the semiconductor diode laser in order to photodynamic cancel therapy as a light source. The ideal light source for photodynamic therapy would be a homogeneous nondiverging light with variable spot size and specific wavelength with stability. After due consideration in this point, in this paper, we used a diode laser resonator of 635nm wavelength. The development laser system have a statistical laser out beam with accuracy control using the constant current control of method and clinic-friendly with compact. In order to protect the diode resonator from the over-current, the rush-current and electrical fault, we specially designed. The most importance therapeutic factor are the radiation mode for cancer therapy. So we developed the radiation mode of CW(Continuous Wave), long pulse, short pulse, and burst pulse and can adjust the exposure time from several milli-second to several minute. The experimental result shows that laser beam power was increased linear from 10mW to 300mW according to the increasing input current and the increasing exposure time. The developed new compact diode laser system have a stability of output power and specific wavelength with easy control and transportable for many applications of PDT.

• Korean Journal of Remote Sensing
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• v.24 no.2
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• pp.99-106
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• 2008

A synthetic aperture radar (SAR) system is of great interest in many fields of civil and military applications because of all-weather and luminance free imaging capability. SAR image quality parameters such as spatial resolution, peak to sidelobe ratio (PSLR), and integrated sidelobe ratio (ISLR) can be normally estimated by modeling of impulse response function (IRF) which is obtained from various system design parameters such as altitude, operational frequency, PRF, etc. In modeling of IRF, however, background clutter environment surrounding the IRF is generally neglected. In this paper, analysis method for SAR mage quality is proposed in the real background clutter environment. First of all, SAR raw data of a point scatterer is generated based on various system parameters. Secondly, the generated raw data can be focused to ideal IRF by range Doppler algorithm (RDA). Finally, background clutter obtained from image of currently operating SAR system is applied to IRF. In addition, image quality is precisely analyzed by zooming and interpolation method for effective extraction of IRF, and then the effect of proposed methodology is presented with several simulation results under the assumption of estimation error of Doppler rate.

• Journal of the Korea Convergence Society
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• v.10 no.7
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• pp.311-316
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• 2019

The purpose of this study is to analyze the preference of haircut according to demographic factors such as age, education, marital status, occupation, monthly income, and residence in order to contribute to the establishment of hair trends of Korean women living in the 4th industrial age. Respectively. After the questionnaire was distributed, 305 questionnaires were analyzed statistically. According to the results of the questionnaire survey, it was found that the higher the age group was, the higher the gradation pattern was, and the difference was statistically different according to the demographic characteristics (p<0.05). By analyzing the shapes and differences of female haircuts according to these demographic characteristics, we will contribute to the establishment of sophisticated and innovative hair trends of Korean women living in the era of the fourth industrial revolution. Through this study, we can find the most ideal hairstyle for Korean women and it will be a starting point for development of various new and creative hairstyles. It is also used as basic data for hairdressing education and it will be actively used as an objective index that can express women 's personality clearly.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.30 no.1
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• pp.77-99
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• 2019

In this study, development directions for smooth introduction of transferring non-specialized libraries to specialized libraries are suggested based on the analysis conducted on non-specialized library librarians and users to investigate and analyze the comparative requirements for specializing libraries, specialization topics, demand for spaces and programs for specialization and view of important factors of each area when operating specialized libraries in future. As a result, first, when introducing a specialized library, it is necessary to derive a specialized topic that can identify and provide the characteristics of the region and the status of existing library. And a demand analysis. Based on this, the subject should be selected through the demand survey of the local residents. Second, from the stand point of targeted subjects of specialized service, it is necessary to provide tailored services by understanding the service range for each age group based on local population distribution and library user analysis. Third, experience-type, lecture-type and view-type can be suggested for specialized programs, considering the characteristics of the specialized subject field. It is ideal to operate combination of the three based on the subject filed details. Also, the characteristics of the subject and the types of program should be considered for specialized spaces. Finally, in order to systematically operate and promote specialized libraries, allocating dedicated personnel, linking with other institutions and strategies of promotion and marketing should be considered.

• Korean Journal of Materials Research
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• v.31 no.2
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• pp.75-83
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• 2021

To cope with automobile exhaust gas regulations, ISG (Idling Stop & Go) and charging control systems are applied to HEVs (Hybrid Electric Vehicle) for the purpose of improving fuel economy. These systems require quick charge/discharge performance at high current. To satisfy this characteristic, improvement of the positive electrode plate is studied to improve the charge/discharge process and performance of AGM(Absorbent Glass Mat) lead-acid batteries applied to ISG automotive systems. The bonding between grid and A.M (Active Material) can be improved by applying the Sand-Blasting method to provide roughness to the surface of the positive grid. When the Sand-Blasting method is applied with conditions of ball speed 1,000 rpm and conveyor speed 5 M/min, ideal bonding is achieved between grid and A.M. The positive plate of each condition is applied to the AGM LAB (Absorbent Glass Mat Lead Acid Battery); then, the performance and ISG life characteristics are tested by the vehicle battery test method. In CCA, which evaluates the starting performance at -18 ℃ and 30 ℃ with high current, the advanced AGM LAB improves about 25 %. At 0 ℃ CA (Charge Acceptance), the initial charging current of the advanced AGM LAB increases about 25 %. Improving the bonding between the grid and A.M. by roughening the grid surface improves the flow of current and lowers the resistance, which is considered to have a significant effect on the high current charging/discharging area. In a Standard of Battery Association of Japan (SBA) S0101 test, after 300 A discharge, the voltage of the advanced AGM LAB with the Sand-Blasting method grid was 0.059 V higher than that of untreated grid. As the cycle progresses, the gap widens to 0.13 V at the point of 10,800 cycles. As the bonding between grid and A.M. increases through the Sand Blasting method, the slope of the discharge voltage declines gradually as the cycle progresses, showing excellent battery life characteristics. It is believed that system will exhibit excellent characteristics in the vehicle environment of the ISG system, in which charge/discharge occurs over a short time.

• Journal of Christian Education in Korea
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• v.64
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• pp.81-107
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• 2020

Church education in Korean churches is facing a very serious crisis. This crisis is a negative perception of the church as viewed by the present society. The negative perception of the church has led to children, adolescents, young adults, and even adults leaving the church. There have been countless studies on the problem of Christian education and its alternatives. However, those problems still remain a matter of church education. The alternatives do not become viable and remain a problem. To solve these problems, a paradigm shift is required, and in order to overcome the crisis of the church, it is necessary to study alternatives and its method factors and find application points. Today's church education is absolutely influenced by postmodernism and informationalization. However, church education is education for Christian identity that transmits Christian faith. This Christian education is facing challenges and crises against its religious and academic identity. Christian education has a responsibility to be aware of this reality and to present alternatives to overcome various crises facing church education. Therefore, it is the task of church education to establish standards so that we can live a life where the Bible becomes the standard. In other words, it is to give them biblical faith. Furthermore, it is necessary to point out and understand Christian faith in the Korean church, which has been evaluated as insufficient. In addition, establishing a Christian worldview and realizing the Kingdom of God that practice justice and love in society are tasks that can be accomplished efficiently through Christian education. Therefore, the Korean church should actively seek ways to support the practice of Christian education as well as church education in forming ideal Christians which is the goal of Christian education.

• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.425-432
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• 2011

To control non-point source pollution at a watershed scale, rainfall-runoff characteristics from forest watersheds should be investigated since the forest is the dominant land use in Korea. Long-term monitoring would be an ideal method. However, computer models have been utilized due to limitations in cost and labor in performing long-term monitoring at the watersheds. In this study, the Geo-spatial interface to the Water Erosion Prediction Project (GeoWEPP) model was evaluated for its runoff prediction from a coniferous forest dominant watersheds. The $R^2$ and the NSE for calibrated result comparisons were 0.77 and 0.63, validated result comparisons were 0.92, 0.89, respectively. These comparisons indicated that the GeoWEPP model can be used in evaluating rainfall-runoff characteristics. To estimate runoff changes from a coniferous forest watershed with various cover degree scenarios, ten cover degree scenarios (10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%) were run using the calibrated GeoWEPP model. It was found that runoff increases with decrease in cover degree. Runoff volume was the highest ($206,218.66m^3$) at 10% cover degree, whereas the lowest ($134,074.58m^3$) at 100% cover degree due to changes in evapotranspiration under various cover degrees at the forest. As shown in this study, GeoWEPP model could be efficiently used to investigate runoff characteristics from the coniferous forest watershed and effects of various cover degree scenarios on runoff generation.