• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.925-928
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• 2014

A dye-sensitized solar cell (DSSC) was fabricated with a nanocrystalline $TiO_2$ film electrode on FTO glass, N719 dye, electrolytes (or $CsSnI_3$), and counter Pt electrode by incorporating it with single-walled carbon nanotubes (SWNTs). SWNTs were combined with $TiO_2$ film, $CsSnI_3$, Pt electrode, separately, and the SWNT-containing cell was compared with a pristine cell in cell performance. We also examined the performance change by pressing $TiO_2$ film, during cell fabrication, inside a high pressure chamber. Mostly, the change of conversion efficiency was compared for each cell, and an atomic force microscopy data were suggested to explain our results.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제36권1호
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• pp.28-38
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• 2010

The factors influencing the relapse and recurrence of skeletal deformity after the orthognathic surgery include various factors such as condylar deviation, the amount of mandibular set-back, stretching force by the soft tissues and muscles around the facial skeleton. The purpose of this report is to recognize and analyze the possible factors of reoperation after orthognathic surgery, due to early relapses. Six patients underwent reoperation after the orthognathic surgeries out of 110 patients from 2006 to 2009 were included in this study. In most cases, clincal signs of the insufficient occlusal stability, anterior open bite, and unilateral shifting of the mandible were founded within 2 weeks postoperatively. Although elastic traction was initiated in every case, inadequate correction made reoperation for these cases inevitable. The chief complaints of five cases were the protruded mandible combined with some degree of asymmetric face and in the other one case, it was asymmetric face only. Various factors were considered as a major cause of post-operative instability such as condylar sagging, counter-clockwise rotation of the mandibular segment, soft tissue tension related with asymmetrical mandibular set-back, preoperatively existing temporomandibular disorder (TMD), poor fabrication of the final wafer, and dual bite tendency of the patients.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2007년도 추계학술대회
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• pp.116-118
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• 2007

Three-dimensional (3D) velocity field information of a laminar flow in a curved micro tube of circular cross-section has been measured using a digital micro holographic particle tracking velocimetry (HPTV). The temporal evolution of instantaneous velocity field of a water flow in a curved micro tube of $100\;{\mu}\;m$ and $300\;{\mu}\;m$ in inner diameter was obtained. The 3D mean velocity field distribution was obtained quantitatively by statistical-averaging of instantaneous velocity fields. At low Dean number (De), a secondary flow was not generated in the curved tube. With increasing Dean number, the secondary flow constituted of two large-scale counter-rotating vortices was formed due to enhanced centrifugal force. To reveal the flow characteristics of high Dean numbers, trajectories of fluid particles were evaluated experimentally from the 3D velocity fields data measured by the HPTV technique. The present experimental results, especially the 3D particle trajectories, would be helpful to design and to understand the mixing phenomena in 3D curved passages of various curved micro-tubes or micro-channels.

• 수산해양기술연구
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• 제28권2호
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• pp.132-143
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• 1992

This paper presents a method in order to calculate the vortex distribution, the streak-line and the time-line around the flat and the cambered otter board in two dimensional flow using the discrete vortex method, and to calculate C sub(L) and C sub(D) of the otter boards varied with the passage of time by the numerical simulation using the Blasu's formula. The results obtained are summarized as follows: 1. Flow pattern around the otter boards calculated by the discrete vortex method was resembled closely that of the visualized photograph. 2. C sub(L) and C sub(D) calculated by the numerical simulation was very similar to the model test. 3. The circulation direction around the otter boards and the action direction of the shearing force can be recognized from the time-line around the otter boards. 4. Flow speed in the back side of the otter boards was faster than that in the front side, and the difference of the flow speed in both side of the cambered otter boards was about 1.3 times greater than that of the flat otter boards. 5. The clockwise vortex was generated in the trailing edge, and the counter-clockwise vortex was generated the leading edge of the otter boards. And they were shown the shape of Karman's vortex varied with the passage of time.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2005년도 연구개발 발표회 논문집
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• pp.459-466
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• 2005

The present study investigates the heat transfer characteristics of a triangular channel. Three different rib configurations are tested. The ribs are installed on two sides of the channel. The rib height (e) to channel hydraulic diameter is 0.079 and the rib-to-rib pitch (p) is 8 times of the rib height. The rotation number ranges from 0.0 to 0.1 while the Reynolds number is fixed at 10,000. The copper blocks with heaters are installed on the channel walls to measure the regionally averaged heat transfer coefficients. For the stationary $45^{\circ}$ and $135^{\circ}$ ribbed channels, a pair of counter rotating vortices is induced by the angled rib arrangements, and high heat transfer coefficients are obtained on the regions near the inner wall for the $45^{\circ}$ ribbed channel and near the leading edge for the $90^{\circ}$ ribbed channel. The heat transfer coefficients of angled ribbed channels are changed little with rotation, whereas those of the transverse ribbed channel are changed significantly with rotation.

• 한국가시화정보학회지
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• 제11권1호
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• pp.28-33
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• 2013

This paper describes aerodynamic characteristics of an Archimedes spiral wind turbine with various angles of attack. The range of angles was controlled from $-30^{\circ}$ (clockwise) to $+30^{\circ}$ (clockwise). The rotating speed of wind turbine at the same angle of attack in both directions was different. The reason why the-maximum rotational speed was observed at $15^{\circ}$ in clockwise direction can be explained based on angular momentum conservation. Quantitative flow visualization around Archimedes wind turbine blade was carried out between $-15^{\circ}$ (clockwise) and $+15^{\circ}$ (counter clockwise) using high resolution PIV method. The relationship between drag force and rotating speeds was discussed. From these results, optimum design on yawing system of Archimedes spiral wind turbine may provide high efficiency on small wind power system.

• 시큐리티연구
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• 제2호
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• pp.211-226
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• 1999

Troublesome problems are being caused by hallucinogenic drugs which come not only from illegal narcotics but also from unprohibited general drug-kinds such as cough-remedy agents of textromerupan, namely, Lamina, Rubi-king and the likes. Abuse and misuse of narcotics permeated into and threatens mental health of socially-known peoples, actor, actress, talents and businessmen as well. This study especially dealt with problems related with Mesampetamin, Rurajaepam, Texstrometropan and Karisofrodol which affects mental behaviour, and considered counter-measures through analysis and developed appropriate system of goods circulation for guidance to be complied by the medicine professionalists. The guidance sought here is recommended to the government ministries for further enforcement of crack-down of the drug crimes. Arquesa in method is recommend as a method of identifying behaviors and facial expressions of abusers and misusers of narcotics at the spot in place. This study is directed to curtailing hallucinogenic drugs use for absolute preventive security by detecting out black dealers of narcotics supplying to the abusers and misusers. There is a need of special education program to cut off the flow of narcotics or drugs crimes into official security force as well as private security personnel. This study introduced a priority and emphasis of real augmentation to theory and practice of the modern scientific security which can protect the mental health of the guarded persons as well especially in the light of security safety curriculum at the school.

• 한국재난정보학회 논문집
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• 제1권1호
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• pp.43-71
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• 2005

Terrorism is the use of violence, especially murder and bombing, in order to achieve political aim or to force a government to do something. Nowadays, instrument of mass destruction are smaller, cheaper, and more readily available. Cellular phones were used as timers in the attacks in Madrid last March. Hijacking an airplane is relatively inexpensive. Finally, the information revolution provides inexpensive means of communication and organization that allow groups once restricted to local and national police jurisdictions to become global. Al Qaeda is said to have established a network in fifty or more countries. These technological and ideological trends increased both the lethality and the difficulty of managing terrorism. Because of the unprecedented scale of Al Qaeda's attacks, the focus is properly on Islamic extremists. But it would be a mistake to limit our concern solely to Islamic terrorists, for that would ignore the way that technology is putting into the hands of deviant groups and individuals' destructive capabilities that were once limited primarily to governments and armies.

• 한국전기전자재료학회논문지
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• 제28권2호
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• pp.85-91
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• 2015

A gasoline engine automobile uses high voltage generation of the ignition coil, igniting and burning mixed fuel in the combustion chamber, which drives the engine. When the electronic control unit intermits a current supplied to the power transistor, counter electromotive force with a low voltage is generated by self induction action in the ignition primary coil and a high voltage is induced by mutual induction action with the primary ignition coil in the second ignition coil. The high voltage is supplied to the ignition plug in the combustion chamber, causing a spark, igniting the compressed mixed fuel. If a very small defect occurs inside the insulating material when a voltage is applied in said ignition coil, the performance of the insulation material will get worse and breakdown by a partial discharge of corona discharge. Thus, in this experiment, we are to contribute to improve the performance and ensure the reliability of the ignition coil by investigating partial discharge characteristics according to the change of voltage and temperature when a voltage is applied to the specimen of the epoxy molding ignition coil.

• 안보군사학연구
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• 통권3호
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• pp.169-196
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• 2005

The point of Bush administraion’s foreign policy is to support the promotion and stability of Democracy in Iraq and counter terrorism and spread of WMD with his strong propulsive force caused by his reelection. In such an environment, there are his leadership, his team, himself, Kim Jung Il, and a new understanding of North Korea after September 11 as the effective factors of Bush administration’s policy toward Pyongyang. Bush administration’s foreign policy of North Korea also shows the process of North Korea’s nuclear weapon program and the future scenario of the Korean Peninsula with "the persistence of solving North Korea’s nuclear weapon program such as the method having done in Lybia", "the holding unconditional talks with Pyongyang, and "the continual concerns with human rights in North Korea." The purpose of Bush administration’s foreign policy of North Korea is to make North Korea do not support terrorism rather than remove the nuclear weapon in North Korea. The process of outlining South Korea’s policy toward North Korea must be considered for "national interest" with reasonable analyses not just hopes For this, South Korea must access systematically human rights of North Korea, prepare projects for a daring approach on North Korea, and strengthen South Korea’s defense ability toward North Korea with deep alliance with U.S and systematize the mutual understanding channel between U.S and South Korea. In conclusion, South Korea must try to get specific methods and practices about Bush administration’s foreign policy of North Korea with national wisdom