• Tribology and Lubricants
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• v.37 no.6
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• pp.208-212
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• 2021

Chemical mechanical polishing (CMP) is a key technology used for the global planarization of thin films in semiconductor production and smoothing the surface of substrate materials. CMP is a type of hybrid process using a material removal mechanism that forms a chemically reacted layer on the surface of a material owing to chemical elements included in a slurry and mechanically removes the chemically reacted layer using abrasive particles. Sapphire is known as a material that requires considerable time to remove materials through CMP owing to its high hardness and chemical stability. This study introduces a technology using electrolytic ionization and ultraviolet (UV) light in sapphire CMP and compares it with the existing CMP method from the perspective of the material removal rate (MRR). The technology proposed in the study experimentally confirms that the MRR of sapphire CMP can be increased by approximately 29.9, which is judged as a result of the generation of hydroxyl radicals (·OH) in the slurry. In the future, studies from various perspectives, such as the material removal mechanism and surface chemical reaction analysis of CMP technology using electrolytic ionization and UV, are required, and a tribological approach is also required to understand the mechanical removal of chemically reacted layers.

• Applied Microscopy
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• v.24 no.1
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• pp.28-40
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• 1994

Xerostomia and xerophthalmia are delicate or serous side effects, occuring when the radiotherapy is administered to the head and neck cancer patient. It is known that the cause of the above side effect is radiosensitivity of serous cells. In this study, the ultrastructural features of the parotid glands of the X-irradiated rats were observed. Sprague-Dawley rats weighing 200-250g each were anesthetized with sodium thiopental, and placed on the Mitsubishi linear accelerator. Only the head and neck areas of animals were exposured at the distance of 80cm, within the area of $30X30cm$, in the depth of 1cm, with the speed of 200R/min. Total doses applied were 3,000R or 6,000R depending on the experimental groups. Animals were sacrificed on the 6th hour, 2nd day and 6th day after the irradiation. Parotid glands were fixed in the 2.5% glutaraldehyde-1.5% paraformaldehyde solution, and followed by refixation in the 1% osmium tetroxide solution. Dehydrated blocks were embedded in araldite mixture, and ultrathin sections were cut. Sections were contrasted with the solution of uranyl acetate and lead citrate, and observed with JEM 100 CX-II electron microscope. The results were as follows: 1. Normal parotid acinar cells are two types; the light and the dark acinar cells. The light acinar cell contains dense secretory granules, whereas dark acinar cells contains granules of medium density with some darker spots within them, or other cells contain granules of medium density with darker rims. 2. Six hours after the irradiation, many acinar cells were degenerated showing variable stages of cytolytic bodies, light bodies, or dense degenerations. Within the acinar cell, Golgi apparatus and granular endoplasmic reticula were most severely altered elements. Granules showed more contrasting densities and irregularities. 3. Two days after the irradiation, some cytolytic bodies, and focal lucent degeneration of cytoplasm, and fine granular alteration of cytoplasmic matrix were pronounced. But other elements including secretory granules are rather looked unlatered. 4. Six days after the irradiation, most severe alterations were seen. Many intracellular canaliculi (or secretion figures), quanta of cytoplasm containing secretion antecedants, severely irregular luminal border, and again contrasting density of secretory granules showing tigroid spots or dense rims were noted. And myoepithelial degenerations were observed not uncommonly. 5. Irregular densities of secretory granules were interpreted as abnormal components of protein or carbohydrate portion are synthesized or abnormally metabolized under severe X-irradiation. 6. Myoepithelial degeneration and related alteration of nerve endings, etc., were suggested as the other causes of xerostomia following X-irradiation. 7. It is requested that radiation doses should be arranged, considering in mind not only the sensitivity of acinar cells but also the myoepithelial and neural functions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.11-11
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• 2008

ZnO has a very large exciton binding energy (60 meV) as well as thermal and chemical stability, which are expected to allow efficient excitonic emission, even at room temperature. ZnO based electronic devices have attracted increasing interest as the backplanes for applications in the next-generation displays, such as active-matrix liquid crystal displays (AMLCDs) and active-matrix organic light emitting diodes (AMOLEDs), and in solid state lighting systems as a substitution for GaN based light emitting diodes (LEDs). Most of these electronic devices employ the electrical behavior of n-type semiconducting active oxides due to the difficulty in obtaining a p-type film with long-term stability and high performance. p-type ZnO films can be produced by substituting group V elements (N, P, and As) for the O sites or group I elements (Li, Na, and K) for Zn sites. However, the achievement of p-type ZnO is a difficult task due to self-compensation induced from intrinsic donor defects, such as O vacancies (Vo) and Zn interstitials ($Zn_i$), or an unintentional extrinsic donor such as H. Phosphorus (P) doped ZnO thin films were grown on c-sapphire substrates by radio frequency magnetron sputtering with various Ar/ $O_2$ gas ratios. Control of the electrical types in the P-doped ZnO films was achieved by varying the gas ratio with out post-annealing. The P-doped ZnO films grown at a Ar/ $O_2$ ratio of 3/1 showed p-type conductivity with a hole concentration and hole mobility of $10^{-17}cm^{-3}$ and $2.5cm^2/V{\cdot}s$, respectively. X-ray diffraction showed that the ZnO (0002) peak shifted to lower angle due to the positioning of $p^{3-}$ ions with a smaller ionic radius in the $O^{2-}$ sites. This indicates that a p-type mechanism was due to the substitutional Po. The low-temperature photoluminescence of the p-type ZnO films showed p-type related neutral acceptor-bound exciton emission. The p-ZnO/n-Si heterojunction LEO showed typical rectification behavior, which confirmed the p-type characteristics of the ZnO films in the as-deposited status, despite the deep-level related electroluminescence emission.

• Archives of design research
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• v.19 no.2 s.64
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• pp.63-72
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• 2006

The design in modern industrial society is the core of corporate administrational strategy and a factor that determines the competitiveness of a country. And the process of purchasing products is the matter related to the awareness of design which expresses the desire to own the design product that consumers prefer, implying that the aesthetic feature of product has become a critical characteristics of product design rather than the technical function of product. In this regard, the development of product design with a new dimension is urgently called for, by analyzing and shedding light on the aesthetic features of factors related to the preference of consumers. This study considers the preceding studies on the aesthetic factors and the reaction of customers to the product design to figure out the importance of factors related to the preference of customers, in an effort to shed light on the aesthetic factors that affect the customers' preference of product and the evaluation of product. In addition to that, this study investigated the preference that Korean and Chinese customers display toward the product and assessed the aesthetic features of preferred product in order to come to the conclusion from the experiment and analysis on how much effect the aesthetic factors and the aesthetic factors by product have on the preference of customers. Therefore, this study tries to propose the data that can be useful for the design of product targeted for consumers in Korea and China, by shedding light on what aesthetic factors that products preferred by consumers in Korea and China have and how much effect such factors have on the preference of consumers in an attempt to provide the guideline on the aesthetic factors of the product design.

• Resources Recycling
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• v.26 no.4
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• pp.79-87
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• 2017

Extraction and separation behaviors of La, Ce, Pr, Nd and Sm from light rare earth multi - component mixed solutions by Cyanex 572 were studied. As extractant concentration increased, the $pH_{50}$ values of all the five components decreased. When extractant concentration was larger than 0.6 M, the separation factor of La and Ce, Nd and Sm was higher than 10, while the separation factor between Ce and Pr, Pr and Nd was as low as 0.5~2.2. Addition of TBP to the 0.6 M Cyanex 572 had little synergistic effect on the phase separation rate and separation factor. From the analysis of experiment results, group separation of [La]/[Pr, Nd, Sm] and [Pr, Nd]/[Sm] could be possible, but in case of the group separation between [La, Ce] and [Pr, Nd] was not available because of the low separation factor between Ce and Pr.

• FLOWER RESEARCH JOURNAL
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• v.18 no.1
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• pp.15-22
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• 2010

These investigations were conducted to standardize several chemical and physical environments affecting in vitro propagation of gametophytes of Climacium japonicum. Propagation of this moss species was established on basal medium containing Knop macro salts and Nitsch and Nitsch trace elements. Primary cultures were initiated from apical shoots of gametophytes. Gametophyte production was accessed using chopped gametophytes, apical shoots and basal shoots. Seven ty pes of culture media and four concentrations of total nitrogen and five strengths of sucrose were tested for in vitro gametophyte production. Light and temperature factors were also evaluated. Apical shoots were the greatest among three types explants used for gametophyte propagation. Medium containing Knop macro salts and Nitsch and Nitsch trace elements was more effective than other types of media. Higher sucrose concentrations showed a positive effect on the elongation and multiplication of gametophytes. Both nitrogen deficiency and excessiveness inhibited gametophyte growth. Light intensity variation showed highly significant changes in numbers, length and fresh weight of gametophytes. Optimum light intensity for gametophyte growth seemed to be around 3000-4000 lx. Both lower and higher temperature had a negative effect on gametophyte propagation and production. This study will provide large scale and high quality propagules, and effective moss propagation system.

• Journal of Astronomy and Space Sciences
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• v.16 no.2
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• pp.227-240
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• 1999

We performed CCD photometric observations of W UMa type contact binary BV Dra during eight nights from May 1996 to June 1999 using 61cm telescope at Sobaeksan Optical Astronomy Observatory, and completed BV R light curves of the system. From our observations, we derived nine new times of minimum lights (five timings for primary eclipse, four for secondary) and determined new light elements with the times of minima observed since 1999. Our BV R light curves and Batten & Lu(1986)'s radial-velocity ones were simultaneously analyzed with contact mode (Mode 3) of Wilson-Devinney's binary model, and the photometric and spectroscopic solutions for BV Dra were solved. In the analysis, we derived the solutions of 1999 light curves with and without spots, respectively. As the results, asymmetry of light curves may be interpreted as produced by the existence of two spots; hot spot on the secondary and cool on the primary. Combining solutions of light curves and radial-velocity ones, absolute dimensions of BV Dra are $M_1=0.40M_{odot}$, $M_2=1.01M_{odot}$, $R_1=0.72R_{odot}$, $R_2=0.40R_{odot}$. In mass-radius diagram, the less massive and hotter primary component of BV Dra is near TAMS and the secondary is near ZAMS, which is very similar to the other W-type W UMa binaries.

• Korean Institute of Interior Design Journal
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• v.20 no.6
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• pp.208-217
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• 2011

Recently the importance of the elderly facilities and the eco-friendly buildings is on the rise, due to the rapid increase of the aged population and the more and more serious global environment issues, respectively. Thus, the purpose of this study is to suggest an eco-environmental improvement plan which aims to improve the quality of life for the aged in planning nursing homes hereafter by reviewing the theory of the eco-friendly architectural concept and the same conceptual design, which become the issues of late, and thus analyzing the state of applying the eco-friendly design techniques to the municipal nursing homes located in Seoul. In this study its direction of the eco-friendly design required in nursing homes was established by reviewing the characteristics which the aged and nursing homes may have, and thus extracting the elements required for the quality of life for them. The theoretical studies showed that the environment-friendly natural elements necessary for the nursing houses are light, air and plants, from which three design elements are obtained: daylighting, natural ventilation and natural landscape. In conclusion, the eco-friendly nursing homes must be planned to improve the quality of life for the aged by recognizing that the eco-friendly architecture concept, emerged as a new paradigm, is the one to be put before all the considerations for those who are sensitive to the environment, and thus reviewing the characteristics found out from them.

• The Journal of the Acoustical Society of Korea
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• v.30 no.3
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• pp.142-148
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• 2011

The final aim of the present study is to develop the intelligent robot, emulating human synesthetic skills which make it possible to associate a color image with a specific sound. This can be done on the basis of the mutual conversion between color image and sound. As a first step of the final goal, this study focused on a basic system using a conversion of color image into sound. This study describes a proposed method to convert color image into sound, based on the likelihood in the physical frequency information between light and sound. The method of converting color image into sound was implemented by using HSI histograms through RGB-to-HSI color model conversion, which was done by Microsoft Visual C++ (ver. 6.0). Two different color images were used on the simulation experiments, and the results revealed that the hue, saturation and intensity elements of each input color image were converted into fundamental frequency, harmonic and octave elements of a sound, respectively. Through the proposed system, the converted sound elements were then synthesized to automatically generate a sound source with wav file format, using Csound.

• Journal of the Korea Fashion and Costume Design Association
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• v.20 no.3
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• pp.79-98
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• 2018

The purpose of this study is to analyze and document special design elements of the knit material, such as yarn, stitch, and gauge used in various types of knit in a collection of men's fashion, and to provide basic data for database design. The analysis covers 37 brand collections of men's clothing, used to collect a total of 1,954 men's knitwear photographs, and others were collected from 12 collections from F/W to 2017 S/S collection through www.vogue.com. The results of the analysis of the knit design elements of the contemporary men's collection since 2011 are as follows. First, there were 1,513 straight yarn (77%) and 440 decorative yarn (23%) types of yarn. There were many different kinds of decorative yarn, such as two tone and melange effect in three colors, and the emergence of hairy yarn, like mohair and angora shannell, which was much common in low gauge's knitwear designs. Second, the frequency was high with low and middle gauges. thin and light high-gauges were often found in S/S collections, but there were also thick types of yarn in low-gauge knitwear. Third, 794 (40.6%) items used basic stitches such as plain stitch, which was the most utilized. The plain stitch, which is the most basic of the knit stitches, appears to be in high demand for its use, along with the use of various decorators. The development of printing and dyeing technologies has led to many designs that utilize the printer for the plain stitch. 326 (16.7 %), of colored jacard stitch, and of 175 (0.9 %) of intasia stitch.