• New & Renewable Energy
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• v.4 no.2
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• pp.68-73
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• 2008

It is very important that constitution of good hetero-junction interface with a high quality amorphous silicon thin films on very cleaned c-Si wafer for making high efficiency hetero-junction solar cells. For achieving the high efficiency solar cells, the inspection and management of c-Si wafer surface conditions are essential subjects. In this experiment, we analyzed the c-Si wafer surface very sensitively using Spectroscopic Ellipsometer for < ${\varepsilon}2$ > and u-PCD for effective carrier life time, so we accomplished < ${\varepsilon}2$ > value 43.02 at 4.25eV by optimizing the cleaning process which is representative of c-Si wafer surface conditions very well. We carried out that the deposition of high quality hydrogenated silicon amorphous thin films by RF-PECVD systems having high density and low crystallinity which are results of effective medium approximation modeling and fitting using spectroscopic ellipsometer. We reached the cell efficiency 12.67% and 14.30% on flat and textured CZ c-Si wafer each under AM1.5G irradiation, adopting the optimized cleaning and deposition conditions that we made. As a result, we confirmed that spectroscopic ellipsometry is very useful analyzing methode for hetero-junction solar cells which need to very thin and high quality multi layer structure.

• Journal of the Korean association of regional geographers
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• v.13 no.4
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• pp.381-395
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• 2007

After the democratization process since 1988, the national scale voting behavior in congressional elections has changed from a rural-government party and urban-opposite party connection to a political regionalism oriented pattern. In this context, the case study with provincial border regions aims to investigate possible party identification change of the region, and to find a relationship between polling score ratio and socio-political characteristics of the candidates. As a result, Yeongdong shows a strong negation to the presumed Chungcheong local party and shows a continuous party identification with the Kyungsang local party. Muju reveals a more or less weakened identification with the Jeolla local party, on the contrary, Kimcheon shows a unchanged strong identification with the Kyungsang local party. The regional neighborhood effect was verified quite partly between the subdivision districts of the border regions. With a application of linear fitting method, it is certified that voters have attached great importance to the belonging party, native place, as well as political career of the candidates as a voting criterion.

• Journal of the Korean Chemical Society
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• v.54 no.1
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• pp.88-92
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• 2010

Isopropyl mercaptan is an important pharmaceutical intermediate and chemical material. And thiourea and triglycol are the main materials for the synthesis of isopropyl mercaptan. Therefore the dissolution of thiourea in triglycol solution is very important for the production of isopropyl mercaptan. The aims of this study are to examine the dissolution kinetics of thiourea in triglycol solution, and to present an alternative process for producing isopropyl mercaptan. In order to investigate the dissolution kinetics of thiourea in triglycol solution, the concentrations of solution and reaction temperature were selected as experimental parameters. It was determined that the dissolution rate of thiourea increased with the increase in solution concentration and temperature. An empirical equation was used in fitting the data. Statistical analysis indicated small errors and the results should be reliable.

• Journal of Soil and Groundwater Environment
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• v.18 no.1
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• pp.46-56
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• 2013

Laboratory scale experiments to remove benzene in solution by using the bio-carrier composed of dead biomass have been performed. The immobilized bio-carrier with dead Bacillus drentensis sp. and polysulfone was manufactured as the biosorbent. Batch sorption experiments were performed with bio-carriers having various quantities of biomass and then, their removal efficiencies and uptake capacities were calculated. From results of batch experiments, 98.0% of the initial benzene (1 mg/L) in 1 liter of solution was removed by using 40 g of immobilized bio-carrier containing 5% biomass within 1 hour and the biosorption reaction reached in equilibrium within 2 hours. Benzene removal efficiency slightly increased (99.0 to $99.4%{\pm}0.05$) as the temperature increased from 15 to $35^{\circ}C$, suggesting that the temperature rarely affects on the removal efficiency of the bio-carrier. The removal efficiency changed under the different initial benzene concentration in solution and benzene removal efficiency of the bio-carrier increased with the increase of the initial benzene concentration (0.001 to 10 mg/L). More than 99.0% of benzene was removed from solution when the initial benzene concentration ranged from 1 to 10 mg/L. From results of fitting process for batch experimental data to Langmuir and Freundlich isotherms, the removal isotherms of benzene were more well fitted to Freundlich model ($r^2$=0.9242) rather than Langmuir model ($r^2$=0.7453). From the column experiment, the benzene removal efficiency maintained over 99.0% until 420 pore volumes of benzene solution (initial benzene concentration: 1 mg/L) were injected in the column packed with bio-carriers, investigating that the immobilized carrier containing Bacillus drentensis sp. and polysulfone is the outstanding biosorbent to remove benzene in solution.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.4
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• pp.267-272
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• 2005

We deposited thin films of organic light-emitting-material $Alq_3$(alumina quinoline) on silicon and slide-glass substrates using thermal evaporation method, and measured spectra of ellipsometry angles ${\Delta}$ and ${\Psi}$ in the photon-energy range of 1.5~5.0 eV using a variable angle spectroscopic ellipsometer. The optical constants, refractive index and extinction coefficient, of $Alq_3$ were determined via the dispersion parameters extracted from the curve-fitting process based on Jellison-Modine dispersion function. The reliability of determined optical constants were verified through the comparison of measured and simulated transmittance curves and the good agreement between simulated absorption-coefficient curves and absorbance spectra measured using a spectrophotometer.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.2
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• pp.169-178
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• 2014

Samples of Clitoria ternatea L. (Cunh$\tilde{a}$) were harvested at 35, 50, 70, and 90 d after a uniformity harvest in a field study designed as a completely randomized design with a total of 18 experimental plots. The dry matter yield of the whole plant was separated quantitatively into leaves, stems, and pods at each harvesting age. Chemical analyses and in vitro gas production kinetics were performed to assess the quality of the plant parts. Yields, chemical composition, and estimates of gas production parameters were analyzed by fitting a mixed statistical model with two types of covariance structures as follows: variance components and an unrestricted structure with heterogeneous variances. Fast and slow gas yielding pools were detected for both leaves and stems, but only a single pool was detected for pods. The homoscedasticity assumption was more likely for all variables, except for some parameters of the gas production kinetics of leaves and stems. There was no presence of typical pods at 35 and 50 d. In the leaves, the fibrous fractions were affected, whereas the non-fibrous fractions were unaffected by the harvesting age. The harvesting age affected the majority of the chemical constituents and gas kinetic parameters related to the stems. The leaves of this legume were the least affected part by the aging process.

• Journal of the Korean Chemical Society
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• v.56 no.6
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• pp.692-699
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• 2012

The aim of the present study is to explore the possibility of utilizing loess and fly ash as well as activated carbon for the adsorptive removal of PCBs in transformer oil. Here, we investigated the effect of various factors such as temperature (5, 25, 55), contact time (30 min-3 day) and adsorbent does (1, 2.5, 5, 10 g) in detail. It was found that PCBs adsorption rate from transformer oil by activated carbon is more favored than loess at the equilibrium time of 60 minutes. The equilibrium data for both activated carbon and loess is fitted well to the Freundlich isotherm model. The rate constant and activation energy of PCBs adsorption in transformer oil on each adsorbent was analyzed by fitting a kinetic model at 5, 25 and $55^{\circ}C$. From the thermodynamic parameters, the PCBs adsorption process for transformer oil/activated carbon and loess system is spontaneous and endothermic in nature.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.24 no.2
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• pp.122-133
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• 2015

The requirements for the successful treatment of all-ceramic restorations are not so different from the ones of conventional restorations. "The provisional restoration followed by an adequate tooth reduction" and "the accurately fitting prostheses with corresponding to final impression" can be the examples of them. Nevertheless, the one which all-ceramic restorations are distinguished from conventional restorations is the additional procedure of so called "bonding". In addition to the application of resin cement between "inner surface of restoration and outer surface of abutment", bonding technology can be also applied to the treatment process of "Post and Core" in particular if the abutments are non-vital teeth. Core build-up for all-ceramic crown is conducted with fiber post and tooth colored composite by considering the properties of the restorations transmitting light. We know well that a vital abutment is easier than a non-vital one to get the targeted goals for clinical success in connection with esthetics and structure. The creation of "Post and Core" with bonding technique is a decisive factor for a long-term success if the abutment is non-vital tooth with dentinal collapse. I would like to share my clinical experience about "post & core build-up and all-ceramic restoration bonding" out of several success strategies of all-ceramic crown with this review article.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.5
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• pp.49-56
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• 2004

A low power consuming voice signal processing and control module was designed using a small $\mu$-controller for use in a totally implantable middle ear system. The module was designed that it can control the implanted system as well as process the fitting algorithm of input sound signal. In ordinary operation mode, the $\mu$-controller processes the applied sound signal for compensating the hearing loss of the patients. When the control signal is applied from the IR receiving module, the $\mu$-controller interrupts the signal processing and executes the order of the control signals such as power on/off, volume up/down. The designed module was implemented and verified the performance of the system through several experiments.

• Korean Journal of Computational Design and Engineering
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• v.15 no.4
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• pp.297-305
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• 2010

Medical image acquisition techniques such as CT and MRI have disadvantages in that the numerous time and efforts are needed. Furthermore, a great amount of radiation exposure is an inherent proberty of the CT imaging technique, a number of side-effects are expected from such method. To improve such conventional methods, a number of novel methods that can obtain 3D medical images from a few X-ray images, such as algebraic reconstruction technique (ART), have been developed. Such methods deform a generic model of the internal body part and fit them into the X-ray images to obtain the 3D model; the initial shape, therefore, affects the entire fitting process in a great deal. From this fact, we propose a novel method that can generate a 3D vertebraic generic model based on the statistical database of CT scans in this study. Moreover, we also discuss a method to generate patient-tailored generic model using the facts obtained from the statistical analysis. To do so, the mesh topologies of CT-scanned 3D vertebra models are modified to be identical to each other, and the database is constructed based on them. Furthermore, from the results of a statistical analysis on the database, the tendency of shape distribution is characterized, and the modeling parameters are extracted. By using these modeling parameters for generating the patient-tailored generic model, the computational speed and accuracy of ART can greatly be improved. Furthermore, although this study only includes an application to the C1 (Atlas) vertebra, the entire framework of our method can be applied to other body parts generally. Therefore, it is expected that the proposed method can benefit the various medical imaging applications.