• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1589-1595
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• 2000

레이저 텍스쳐와 미케니칼 텍스쳐 컴퓨터 하드디스크의 마찰과 마코 매카니즘이 Contact Start/Stop test 실행후의 특성들에 대해 연구되었다. 다양한 분석적이고 기계적인 테스트 기술들이 이용되었다. 형상, 조도, 화학적 조성, 기계적 성질, CSS 로부터 기인된 코팅의 마찰특성들에 대해 그 변화들을 조사하였다. 즉, AFM(Atomic Force Microscopy), Nano-Indentation, Nano-Scratch, TOF-SIMS(Time of Flight Secondary Ion Mass Spectroscopy), AES(Auger Electronic Spectroscopy)등이 이 연구에 적용되었다. 레이저 텍스쳐 범프의 표면조도와 미케니칼 텍스쳐 지역의 표면조도는 각각 대략적으로 4nm 와 7nm 감소되었다. 탄성계수와 경도값은 CSS test후에 증가하였고 가장 바깥쪽의 코팅층의 변형강화가 생겨났다. 자성층과 Ni-P 층 사이에 점착성의 문제가 확인되었다. TOF-SIMS 분석은 C 와 $C_2F_5$의 세기에 있어서 감소를 드러냈고 이것은 코팅 표면에 윤활제 요소의 마모를 확실시 할수 있는 결과로 나타났다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권4호
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• pp.265-271
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• 2000

A non-contact battery charger for cellular phone is designed using half-bridge series resonant converter. This converter utilizes series resonance to reduce the undesirable effect of large leakage inductance of the detachable transformer and ZVS operation can reduce switching loss and switching noise. In this paper, analysis and design procedure of half-bridge series resonant converter with detachable transformer is presented. The input voltage is 85VAC∼270VAC, and the output voltage and current is 4.1V and 800mA, respectively. Furthermore, a method of calculating the secondary current of the transformer to control the battery charging current in the constant current charging mode is proposed. The performance of the charger is verified through experiments.

• 전력전자학회논문지
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• 제17권5호
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• pp.445-452
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• 2012

The impurity detection method applied to existing discriminated the normality(R, L, C) and impurity(Metal) load using mutual RFID/ID method in the contactless power supply in which the primary side and the secondary side are completely separation by using the contactless transformer. However, this kind of system is caused the high cost of the system and complexity of control. Therefore, in this paper was proposed the contact-less power transfer using the primary current that determine normality or impurity load by compare the primary current Amplitude to reference quantity value and design the 3[W] contact-less power transfer and conduct an experiment for demonstrate the validity.

• 한국군사과학기술학회지
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• 제23권1호
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• pp.37-42
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• 2020

This study is for a bulletproof experiment through speed acceleration of steel ball(2.385 mm) at the laboratory level. The secondary propulsion method is used for speed acceleration, which uses a sabot assembly consisting of a sabot body, a plunger, water, and a sabot cap. At the core of the secondary drive, it is important that the energy in the water of the private particle is transferred well to the steel ball. The experiment was conducted by selecting a plunger that pushes water and water charged with variables. judging that the longer the contact time, the greater the energy transferred to the steel ball. As a result of experiments with each variable, the amount of water does not affect the speed acceleration efficiency of the steel ball and, when the length of the plunger is increased by 200 %, the speed of the steel ball can be accelerated up to 130 m/s.

• 한국전기전자재료학회논문지
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• 제31권1호
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• pp.6-10
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• 2018

Ni germanide (NiGe) is a promising alloy material with small contact resistance at the source/drain (S/D) of Ge MOSFETs. However, it is necessary to reduce the specific contact resistance between NiGe and the doped Ge S/D region in high-performance MOSFETs. In this study, a novel method is proposed to reduce the specific contact resistance between NiGe and p-type Ge (p-Ge) using a Tb interlayer. The specific contact resistance between NiGe and p-Ge was successfully decreased with the introduction of the Tb interlayer. To investigate the mechanism behind the reduction in the specific contact resistance, the elemental distribution and crystalline structure of NiGe were analyzed using secondary ion mass spectroscopy and X-ray diffraction. It is likely that the reduction in specific contact resistance was caused by an increase in the concentration of boron in the space between NiGe and p-Ge due to the influence of the Tb interlayer.

• 한국학교ㆍ지역보건교육학회지
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• 제1권1호
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• pp.119-130
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• 2000

The purpose of this study was to serve as a basis for more effective sex education, by examining the influence of obscene media on elementary school student's sex consciousness. For attaining the purpose, the research questions were posed as follows: 1) What's general characteristics of elementary school students? 2) How much are elementary school students exposed to obscene media? 3) Is their sex consciousness different according to the degree of being exposed to obscene media and the appearance of secondary sex characteristic? The subject of study were the 400 male and female students who were in the sixth grade at elementary school in the city of Paju. The questionnaire survey was conducted to find out their general characteristics, sex consciousness and degree of being exposed to obscene media. The conclusions were as follows; 1) Basic Information 94% of the students investigated were living with their parents. The greatest number of their parents were in their fourties. Concerning the religion of their families, 47.5% belonged to Christianity or Catholicism. 47.3% got in touch with obscene media, which indicated that the harmful influence of that media was great. Their basic knowledge of pregnancy was very poor, as 27.2% weren't sure whether being pregnant could be caused only by shaking hands, hugging or kissing. 34.7% considered it a natural behavior to contact the other sex. Regarding their practice of sexual behavior, they'd have an experience of hugging or kissing. 2) Group Comparison The female students underwent the appearance of secondary sex characteristic faster than the male students. As a result of examining if their degree of being exposed to obscene media was affected by the presence or absence of secondary sex characteristic, no statistically significant difference existed in all the groups: the entire group, male student group and female student group. There appeared, however, statistically significant differences between male and female students, as the number of male student who hadn't yet been exposed to obscene media was less than that of female student who hadn't. And the number of male student who had been much exposed to obscene media was more than that of female student who had. 3) Sex Knowledge, Sex Attitude and Sex Practice The extent of making contact with obscene media didn't make statistically significant difference to the sex knowledge of all the groups. But more extent of getting in touch with obscene media led to more sex attitude and sex practice in the entire group. However, as a result of analyzing these things by the presence or absence of secondary sex characteristic, it's found in general that the group that had secondary sex characteristic possessed statistically better sex knowledge than the other group that hadn't. For the male students, there appeared little disparities in three subareas of sex knowledge, sex attitude and sex practice. For the female students, however, the group that had secondary sex characteristic owned better sex knowledge than the other group that hadn't, and the former group looked upon sex attitude as more natural.

• Archives of Reconstructive Microsurgery
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• 제5권1호
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• pp.16-23
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• 1996

The omental pedicle based on right gastroepiploic vessels is designed new experimental model for prefabrication(revasculirization) of skin flaps in rats. A $2.5{\times}4cm$ pack of omentum with right gastroepiploic vessels was transferred under a bipediceld panniculocutaneous flap which is $2.5{\times}8cm$ size. At day 7, all four margin was divided and the flap was rasied as an secondary island flap connected only by its vascular pedicle, then the composite flap sutured back in place. The flap perfusion was examined by dermofluorometry and flap survival area was measured at day 12. The Secondary island flap demonstrated a dye fluorescence index(DFI%) of $31.38{\pm}12.33$ and survival rate $80.47{\pm}9.61$ The survival rate was increased when DFI% and contact surface between vascular carrier and skin flap was increased. An india ink injection and histologic examination provided visual evidence of revasculization. The omental pedicle is a promising and safe model for revasculirization of other tissues.

• 한국산업융합학회 논문집
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• 제25권3호
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• pp.333-340
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• 2022

Recently, the use of large-capacity secondary batteries for electric vehicles is rapidly increasing, and accordingly, the demand for technologies and equipment for battery reliability evaluation is increasing significantly. The existing short circuit test equipment for evaluating the stability of the existing secondary battery consists of relays, MCs, and switches, so when a large current is energized during a short circuit, contact fusion failures occur frequently, resulting in high equipment maintenance and repair costs. There was a disadvantage that repeated testing was impossible. In this paper, we developed an electronic short circuit test device that realizes stable switching operation when a large-capacity power semiconductor switch is energized with a large current, and applied smart ICT technology to this electronic short circuit stability test system to achieve high speed and high precision through communication with the master. It is expected that the inspection history management system based on data measurement, database format and user interface will be utilized as essential inspection process equipment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.347-350
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• 2006

The high efficiency full-bridge LLC resonant converter using a contact-less transformer is proposed for the photovoltaic power generation system. For the series resonance with a series capacitor, the LLC resonant converter utilizes the leakage inductance and magnetizing inductance of a contact-less transformer. Unlike the conventional series resonant converter operated to the continuous resonant current at above resonance frequency, the proposed converter operates to the discontinuous resonant current at the narrow frequency control range below resonance frequency. Due to the discontinuous mode resonant current, the proposed converter can be achieved the zero voltage switching (ZVS) in the primary switches and the zero current switching (ZCS) in the secondary rectification diodes without any auxiliary circuit. In this paper, the experimental results of the proposed full-bridge LLC resonant converter using a contact-less transfonner are verified on the simulation based on the theoretical analysis and the 150W experimental prototype.

• KSTLE International Journal
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• 제1권1호
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• pp.12-20
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• 2000

Nano-wear and friction of carbon overcoated laser-textured and mechanically-textured computer hard disk were characterised after contact start/stop (CSS) wear test. Various analytical and mechanical testing techniques were employed to study the changes in topography, roughness, chemical elements, mechanical properties and friction characteristics of the coating arising from the contact start/stop wear test These techniques include: the atomic force microscopy (AFM), the continuous nano-indentation test, the nano-scratch test, the time-of-flight secondary ion mass spectroscopy (TOF-SIMS) and the auger electron spectroscopy (AES). It was shown that the surface roughness of the laser-textured (LT) bump and mechanically textured (MT) Bone was reduced approximately am and 7nm, respectively, after the CSS wear test. The elastic modulus and hardness values increased after the CSS test, indicating straining hardening of the top coating layer, A critical load was also identified fer adhesion failure between the magnetic layer and the Ni-P layer, The TOF-SIMS analysis also revealed some reduction in the intensity of C and $C_2$$F_59$, confirming the wear of lubricant elements on the coating surface.