• Vacuum Magazine
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• v.2 no.2
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• pp.12-16
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• 2015

Organic photovoltaics (OPVs) have attracted significant interest in an interdisciplinary research field for the decades as a next-generation photovoltaic device due to their unique advantages. One of requirements for OPVs having high power conversion efficiency is the favorable energy level alignment between the electrode/organic and organic/organic interfaces to manage the exciton dissociation and improve the charge transport. In this review, strategies to enhance the OPV performance by controlling the energy level alignment are discussed. The insertion of an exciton blocking layer leads to the efficient dissociation of photogenerated excitons at the donor/acceptor interface enhancing the short-circuit current density. The choice of a donor having a high ionization energy and an acceptor having a low electron affinity increases the open-circuit voltage. The insertion of an appropriate work function modifier which reduces the charge injection barrier removes the S-kink in current density-voltage characteristics of OPVs and improves the fill factor. This review would give a valuable guide to design the efficient OPV structure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.93-94
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• 2007

다양한 LDD(lightly doped drain)에 따른 n-channel poly-Si TFT (thin film transistor)에 대하여 보고한다. 유리 기판 위에 ELA를 이용하여 만들어진 Polycrystalline silicon (poly-Si)은 TFT-LCD의 응용을 위한 재료로써 우수한 특성을 갖는다. 제작된 n-channel TFT는 절연층으로 $SiN_x$, $SiO_2$의 이중 구조를 갖는다. 다양한 LDD에 따른 n-channel poly-Si TFT의 문턱전압($V_{TH}$), ON/OFF 전류비 ($I_{ON}/I_{OFF}$), 포화전류($I_{DSAT}$)는 TFT의 보다 좋은 성능을 위해 연구된다. 짧은 LLD 길이를 가진 n-channel poly-Si TFT의 문턱전압은 작고, 포화전류의 값은 크다. 또한 긴 LLD 길이를 가진 n-channel poly-Si TFT는 작은 kink effect를 가진다.

• The Journal of Information Technology
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• v.9 no.1
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• pp.9-19
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• 2006

Medications or conitive-behavior methods have been mainly used as a treatment of alcoholism. lately the virtualy technology has been applied to the kink of alcoholic disorders. A virtual environment makes him having avility to over come the drink. In this study, we were implemented by making panorama images and 3D object modules using 3D MAX, VRML, JAVA. And the BAR stimulator that composed with a position sensor, head mount display, and audio system, is suggested. To illustrate the physiological difference between a person who has a alcoholism and without a liquor bottle, heart rate was measured during experiment, and also measured a person's HR after the virtual reality training. The system measures the Physiological signals such as ECG, Temperature, analyzes those data automatically. The system has two parts, one is physiological data acquisition part which gets the body signal, and the other one is mobile nuit which includes signal processing and transmission functions, And Bluetooth allows two parts to communicate with each other. we demonstrated the subjective effectiveness of virtual reality psychotherapy through the clinical experiment.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.50.3-50.3
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• 2019

The EUV wave is a disturbance that has been believed to be the fast-mode (shock) wave, which can propagate passing through magnetic field lines. After the passage of EUV waves, coronal streamers start to show kink-mode oscillations, and the footpoints, i.e., magnetic separatrices, of the oscillating streamers are observed as the so-called stationary front. We compare the stationary front observed by EUV imagers and coronal streamers observed in coronagraphic images. We analyze the successive events occurred in September 2011. We find that the stationary fronts are consistent with the coronal streamer boundaries, and they are located along the boundaries of coronal holes and active regions. Our results confirm that EUV waves are in fact fast-mode waves and demonstrate that the stationary front is a promising tool to probe into the source of slow solar wind that is the boundary of coronal streamers on the solar surface.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.47.1-47.1
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• 2021

Transverse magnetohydrodynamic waves often called Alfvénic (or kink) waves have been often theoretically put forward to solve the outstanding problems of the solar corona like coronal heating, solar wind acceleration, and chemical abundance enhancement. Here we report the first spectroscopic detection of Alfvénic waves around a sunspot at chromospheric heights. By analyzing the spectra of the Hα line and Ca II 854.2 nm line, we determined line-of-sight velocity and temperature as functions of position and time. As a result, we identified transverse magnetohydrodynamic waves pervading the superpenumbral fibrils. These waves are characterized by the periods of 2.5 to 4.5 minutes, and the propagation direction parallel to the fibrils, the supersonic propagation speeds of 45 to 145 km s-1, and the close association with umbral oscillations and running penumbral waves in sunspots. Our results support the notion that the chromosphere around sunspots abounds with Alfvénic waves excited by the mode conversion of the upward-propagating slow magnetoacoustic waves.

• The Journal of the Petrological Society of Korea
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• v.10 no.2
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• pp.82-94
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• 2001

The main geological structure of the Ogcheon belt in the Buunnyeong area, Mungyeong, which consists of three stratigraphic sequences, Joseon and Pyeongan Supergroups and Daedong Group, is characterized by the development of ESE-vergence structural unit (Dangok unit) and WNW-vergence structural units (Samsil and Bugongni units) onto an autochthonous unit (Buunnyeong unit). Three phases of deformation are recognized in this area. The lent phase of deformation coourred under the WNW-ESE compression, forming an upright-open fold (Buunnyeong-I fold) with NNE axial trend in the Buunnyeong unit. The second phase of deformation also under the WNW-ESE compression formed the Dangok, Samsil and Bugongni units, resulting in the further closing of the Buunnyeong-I open fold, the elongation of pebbles in the conglomerate rocks of a basal sequence of the Daedong Group, recumbent folds (Buunnyeong-II fold) and drag folds (Dangok fold) with NNE axial trend in the Buunnyeong and Dangok units, respectively. The third phase of deformation formed kink folds with its axis p1unging subvertically. The first and second phases of deformation took place before and after the deposition of the Daedong Group of the Upper Triassic -Lower Jurassic, respectively. These first two deformation events, which occurred under the same WNW-ESE compressional field, produced the regional NNE trend of geological structure in the Joseon and Pyeongan Supergroups of this area.

• Applied Chemistry for Engineering
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• v.10 no.3
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• pp.427-431
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• 1999

Copolyester resins for the coil coating process of aluminium and steel strip were synthesized and their thermal properties, molecular weight and solvent solution characteristics were examined. Copolyesters were obtained by two step reactions. The first step was to prepare bishydroxyethyl terephthalate (BHET), bishydroxyneopentyl terephthalate (BHNPT), bishydroxyethyl isophthalate (BHEI), bishydroxyneopentyl sebacate (BHNPS), bishydroxyneopentyl adipicate (BHNPA) and bishydroxyethyl adipicate (BHEA) oligomers by esterification reactions. The second step was the polycondensation reaction utilizing those oligomers to obtain relatively high molecular weight copolyesters (Mw = 30,000~59,000 g/mol) as measured by GPC. These copolyesters were amorphous polymers as shown by DSC without $T_m$ peaks probably due to the kink structure introduced by BHET oligomer and relatively large free volume by bulky BHNPT and BHNPS oligomers. The copolyester samples with half of BHET oligomer substituted by BHNPT while keeping BHEI (0.3 mole) and BHNPS (0.1 mole) ratio constant showed glass transition temperature above $40^{\circ}C$ and good solubility in toluene both at low ($-5^{\circ}C$) temperature and room temperature.

• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.1014-1021
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• 1997

Studies were carried out on the preparation of several kinds of pulps from Sponge gourd fiber by KP, ASP, SP PAP, AP and addition of AQ pulping process. These unbeaten and beaten pulping fibers were observed their characteristics and fiber structure by SEM, FQA, Image analyzer and Micro projector. The results were summarized as follows; 1) The cooking condition which is the possible defibrilation of Shives are KP base($160^{\circ}C$, 2hr.), ASP base($155^{\circ}C$, 4hr.), PAP base($160^{\circ}C$, 1hr.). From the results, the kappa no. had the range of 12, 25, 10 each other. 2) The pulp yields of sponge gourd fiber obtained the range of KP 50~55%, ASP&60~70% and PAP 45~50%. SP base have the highest and contnets of KP&PAP base are much the same as woods. 3) Increasing amount of NaOH on Pulping was accelerated the defibrilation of Shives and was changed a morphology of pulping fiber quality such as fiber length, curl and kink index. 4) Addition of AQ on pulping process of sponge gourd fiber had a affect to raise the rate of delignification while protecting cellullosic components against degradation, especially defibrilation was very excellent, beated pulp much more easily and increased the fibrilation. 5) ASP system have higher bulk density, fiber bonding and protecting cellullosic components against degradation than KP or PAP. 6) The color reactions of the "C" stain solution showed blue or blue-gray with clean and transparency thin cell wall.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.8
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• pp.2158-2166
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• 1994

In order to understand the package crack emanating from the edge of leadframe after the delamination between leadframe and epoxy molding compound in an electronic packaging of surface mounting type, the M-integral and J-integral in fracture mechanics are obtained. The effects of geometry, material properties and molding process temperature on the package crack are investigated taking into account the temperature dependence of the material properties, which simulates a more realistic condition. If the temperature dependence of the material properties is considered the result of analysis conforms with observations that the crack is kinked at between 50 and 65 degree. However, in case of constant material properties at the room temperature it is found that the J-integral is underestimated and the kink crack angle is different form the observation. The effects of the material properties and molding process temperature on J-integral and crack angle are less significant that the chip size for the cases considered here. It is suggested that the geometric factors such as ship size, leadframe size are to be well designed in order to prevent(or control) the occurrence and propagation of the package crack.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1416-1417
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• 2011

킹크효과를 억제할 수 있는 새로운 f-모양 트리플게이트 구조를 가지는 다결정실리콘 박막트랜지스터는 추가적인 공정과정 없이 제안 및 제작되었다. 이러한 다결정실리콘 박막트랜지스터의 채널에는 순차적인 횡방향 고체화(Sequential Lateral Solidification, SLS)나 CW 레이져 횡방향 결정화(CW laser Lateral Crystallization, CLC) 등과 같은 방법으로 제작된 횡방향으로 성장시킨 그레인이 있다. 이 소자의 전체적인 전류흐름은 횡방향으로 성장시킨 그레인 경계에 강력하게 영향을 받는다. f-모양 트리플게이트에는 횡방향으로 성장시킨 그레인과 평행한 방향으로 위치한 채널, 그리고 수직인 방향으로 위치한 채널이 있다. 이 소자는 f-모양 게이트 구조에서의 비대칭 이동도를 이용하여 다결정실리콘 박막트랜지스터의 킹크효과를 효과적으로 억제시킬 수 있다는 사실을 실험과 시뮬레이션을 통해 검증되었다. 우리의 실험 결과는 이 논문에서 제안된 f-모양 트리플게이트 박막트랜지스터가 기존의 박막트랜지스터와 비교할 때 더 효과적으로 킹크 효과를 감소시킬 수 있다는 것을 보여주었다. 또한 고온 캐리어 스트레스 조건에서의 신뢰성도 개선할 수 있음이 확인되었다.