• Advances in nano research
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• v.2 no.1
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• pp.23-56
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• 2014

The significant growth of the Si photovoltaic industry has been so far limited due to the high cost of the Si photovoltaic system. In this regard, the most expensive factors are the intrinsic cost of silicon material and the Si solar cell fabrication processes. Conventional Si solar cells have p-n junctions inside for an efficient extraction of light-generated charge carriers. However, the p-n junction is normally formed through very expensive processes requiring very high temperature (${\sim}1000^{\circ}C$). Therefore, several systems are currently under study to form heterojunctions at low temperatures. Among them, carbon nanotube (CNT)/Si hybrid solar cells are very promising, with power conversion efficiency up to 15%. In these cells, the p-type Si layer is replaced by a semitransparent CNT film deposited at room temperature on the n-doped Si wafer, thus giving rise to an overall reduction of the total Si thickness and to the fabrication of a device with cheaper methods at low temperatures. In particular, the CNT film coating the Si wafer acts as a conductive electrode for charge carrier collection and establishes a built-in voltage for separating photocarriers. Moreover, due to the CNT film optical semitransparency, most of the incoming light is absorbed in Si; thus the efficiency of the CNT/Si device is in principle comparable to that of a conventional Si one. In this paper an overview of several factors at the basis of this device operation and of the suggested improvements to its architecture is given. In addition, still open physical/technological issues are also addressed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.1
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• pp.32-35
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• 2011

Top-emission device has a merit of high aperture ratio and narrow emission spectrum compared to that of bottom-emission one. Emission spectra of top-emission organic light-emitting diodes depending on a layer thickness and view angle were analyzed using a theory of microcavity. Device structure was manufactured to be Al (100 nm)/TPD/$Alq_3$/LiF (0.5 nm)/Al (2 nm)/Ag (30 nm). N,N'-diphenyl-N,N'- di (m-tolyl)-benzidine (TPD) and tris (8-hydroxyquinoline) aluminium (Alq3) were used as a hole-transport layer and emission layer, respectively. And a thickness of TPD and Alq3 layer was varied in a range of 40 nm~70 nm and 60 nm~110 nm, respectively. Angle-dependent emission spectrum out of the device was measured with a device fixed on a rotating plate. Since the top-emission device has a property of microcavity, it was observed that the emission spectrum shift to a longer wavelength region as the organic layer thickness increases, and to a shorter wavelength region as the view angle increases. Layer thickness and view-angle dependent emission spectra of the device were analyzed in terms of microcavity theory. A reflectivity of semitransparent cathode and optical path length were deduced.

• Journal of the Korean Society of Combustion
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• v.9 no.2
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• pp.38-44
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• 2004

The evolution of incipient soot particles has been examined by high resolution electron microscopy (HRTEM) and elemental analyzer in ethylene-air inverse diffusion flames. Laser Induced Incandescence(LII) and laser scattering methods were introduced for examining the soot volume fraction and morphological properties in combustion generated soot qualitatively. Soot particles, collected by thermophoretic sampling, were analyzed by using HRTEM to examine the nano structure of precursor particles. HRTEM micrographs apparently reveal a transformation of condensed phase of semitransparent tar-like material into precursor particles with relatively distinct boundary and crystalline which looks like regular layer structures. During this evolution histories, C/H analysis was also performed to estimate the chemical evolution of precursor particles. The changes of C/H ratio of soot particles with respect to residence time can be divided into two parts: one is a very slowly increasing regime where tar-like materials are transformed into precursor particles (inception process) the other is an increasing region with constant rate where surface growth affects the increase of C/H ratio dominantly (surface growth process). These results provide a clear picture of a transition to mature soot from precursor materials.

• Journal of the Semiconductor & Display Technology
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• v.21 no.3
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• pp.119-124
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• 2022

Top emission organic light-emitting diode (TEOLED) is commonly used because of high efficiency and good color purity than bottom - emission organic light-emitting device (BEOLED). Unlike BEOLED, TEOLED contain semitransparent metal cathode and capping layer. Because there are many characteristics to consider just simple thickness change, optimizing organic thickness of TEOLED for microcavity is difficult. So, in this study, we optimized Device capping layer at unoptimized micro-cavity structure TEOLED device. And we compare only capping layer with unoptimized microcavity structure can overcome optimized micro-cavity structure device. We used previous our optimized micro-cavity structure to compare each other. As a result, it has been found that the efficiency can be obtained almost the same or higher only capping layer, which is stacked on top of the device and controls only the thickness and refractive index, without complicated structural calculations. This means that higher efficiencies can be obtained more easily in laboratories with limited organic materials or when optimizing new structures etc.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.5
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• pp.2113-2120
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• 2013

In this study, an efficient machine vision based inspection system is developed for the in-line measurement of phosphor resin dispensing shapes on LED chip package. Since the phosphor resin (target material) has semitransparent characteristics, illuminated light beam is reflected from the bottom of the chip as well as from the surface. Since such phenomenon can deteriorate inspection reliability, a white LED and a 635nm laser slit beams are experimentally tested to decide suitable illumination optics. Also, specular and diffuse reflection methods are tested to decide suitable optical triangulation. As a result, it can be known that the combination of a white slit beam source and specular reflection method show the best inspection results. The Catmull-Rom spline interpolation is applied to the obtained data to form smoother surface. From the results, it can be conclude that the developed system can be sucessfully applied to the in-line inspection of LED chip packaging process.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.1
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• pp.71-81
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• 2009

Die steel for plastic molding were used as mold material of automobile parts and electronic component industry. The material of this paper has superior to mechanical properties, such as repair weldability, corrosion resistance and high temperature strength, required mold parts for semitransparent. Laser-induced surface hardening technology is widely adopted to improver fatigue life and wear resistance via localized hardening at the surface of mold parts. The objective of this research work is to investigate on the characteristics of surface hardening of the laser process parameters, such as beam travel speed, laser power and defocsued spot position, for the case of die steel for plastic molding. Lens for surface hardening of large area is plano-convex type with elliptical profile to maintain uniform laser irradiation. According to the experimental results, large size of hardened layer at the surface of die steel for plastic molding was achieved, and microstructure of this layer was lath martensite. Optimal surface status and mechanical property of hardened layer could be obtained at 1095Watt, $0.25{\sim}0.3m/min$, 0mm (focal length: 232mm) for laser power, beam travel speed, and focal position. Where, heat input was $0.793{\times}10^{3}J/cm^2$, and width of hardened layer was 27.58mm.

• Korean Journal of Head & Neck Oncology
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• v.25 no.2
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• pp.174-177
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• 2009

Parathyroid cyst are rare lesion of the neck and superior mediastinum. They are classified as either functional or nonfunctional based on the presence or absence of hyperparathyroidism. They typically present as a palpable neck mass, or as an incidental finding during neck surgery. So, it must be included within the differential diagnosis of a neck lump. A 48-year old woman was admitted to our hospital for evaluation of left anterior neck mass. Physical finding showed soft, movable, non-tender mass on the lower left third of the neck. Laboratory findings revealed normal thyroid function and normal serum calcium level. On previous history, patient underwent two times sono-guided fine needle aspiration at local clinic, and about 10cc clear watery aspirate was noted. Computerized tomography findings showed non-enhancing hypodense cystic lesion on left thyroid area with tracheal deviation to right side. Preoperative diagnosis was thyroid cyst, and thyroidectomy was planed. Intra-operative finding showed huge cystic mass occupying the left thyroid area and smooth, shiny, semitransparent thin cyst wall was noted, which was loosely attached to the thyroid. The cyst was easily dissected free from the thyroid and surrounding tissues. After cyst removal, pathological study confirmed as a parathyroid cyst.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.5
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• pp.85-90
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• 2017

Mica-glass ceramics has features such as micro-sized crystals, high strength, chemical resistance, semitransparent optical properties, etc. Due to its superior material properties, mica glass ceramics have increasing applications in dental and medical components, insulation boards, chemical devices, etc. In many applications, especially for dental and medical components, ultra-precise polishing is required. However, it is known to be a very difficult-to-grind material because of its high hardness and brittle properties. Thus, in this study, a newly developed ultra-precise polishing method is applied to obtain nano-level surface roughness of the mica glass ceramics using magnetorheological (MR) fluids and nano abrasives. Nano-sized ceria particles were used for the polishing of the mica glass ceramics. A series of experiments were performed under various polishing conditions, and the results were analyzed. A very fine surface roughness of Ra=6.127 nm could be obtained.

• The Research Journal of the Costume Culture
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• v.20 no.1
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• pp.49-61
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• 2012

This study focuses on looking at the influence of silhouette in the 1930s on fabric pattern design by comprehending how differently flower-pattern design were found according to clothing silhouette. The period scope of research was limited to 1930s, and the research object was set as the flower patterns seen in the designer's high-fashion and the women's daily apparel as well as the clothes for sports and leisure activities. Based on the above research scope, the researcher investigated the clothing silhouette and the textile patterns in 1930s by reviewing the literature about domestic and foreign books, research papers, domestic and foreign fashion magazines, information on the Internet. A glance at the women's clothing in the 1930s reveals that they emphasized something inactive, elegant, feminine and that great popularity was given to feminine silhouette that closely fitted the body and long and slim, as skirts became longer and longer. Like this, silhouette refused traditional methods in the technique of expressing flower patterns that were on-trend in that period, pursued the freedom of line and form, used shadowing technique by means of free pens and brushes and the effect of watercolors. It also arranged in a semitransparent way and painted contours alone, too. Flower patterns fell into two categories: amorphous abstract patterns and standardized abstract patterns. The patterns expressed themselves, divided into small-scale irregular patterns and abstract geometric patterns that filled the entire textile.

• Journal of architectural history
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• v.5 no.1 s.9
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• pp.50-72
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• 1996

The typical Japanese house has the characteristics of open dwellings to make them cool in the hot and humid summer. And then the traditional town house 'Machiya', being built very closely to each other and walled up both sides, it has taken the open-oriented characteristics in itself. The purpose of this study is to clarify that the open-oriented of traditional 'Machiya' has been succeeded to the new 'Machiya' in the latest. The new 'Machiya' shows the open-oriented, taking the ventilative 'Huki-nuke' space of traditional 'Machiya' as the new spatial formal elements, in the changes such as scale material space organization. The characteristics of 'Huki-nuke' space are represented as follows ; 1. The facade of the traditional 'Machiya', which has taken on a semitransparent qualty, has been generally changed to the closing qualty except for the open parts of shop and garage. This facade of the new 'Machiya' has been taken to be in keeping with the existing town as much as possible. 2. A series of three rooms, composed of shop/living dining kitchen/room from the road, have been dispersed to every floors in a building with a very extensive scale. But this serial and linear type remains as the loosefit space, and the long dwellings of the upper stories are divided by type each dwelling unit. 3. 'Tori-niwa', which is a consecutive and penetrating space, connects the road with the rooms of dwelling and functions as the circulation of man thing energy, The new 'Machiya' changed to the multi-story, the corridor and the stair have been fumed up as the elements in the place of 'Tori-niwa' The 'Huki-nuke' space was locted in the hall, stairwell, living dining kitchen room, and so on. 4. The small court yard 'Tsubo-niwa' and back yard 'Ura-niwa' at the both ends of living spaces would be made a hole in a series of rooms and enclosed by the neighboring 'Machiya'. On the contrary the new 'Machiya' at present takes in the private and closing organization enclosing the innercourt. 5. The open-oriented ${\ulcorner}$In${\lrcorner}$ or ${\ulcorner}$Out${\lrcorner}$ is not brought out because of the delicate spatial formal configuration in the traditional 'Machiya'. But the open-oriented ${\ulcorner}$In${\lrcorner}$, all sides being closed by walls, is well brought out in the new 'Machiya'.