• Journal of Welding and Joining
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• 제23권5호
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• pp.14-19
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• 2005

In high speed $CO_2$ welding, it has been blown to produce no sound bead with undercut or humping bead. In this study welding phenomena through synchronized high speed camera and output welding voltage and current waveform has been analyzed. For the purpose to improve a welding bead, effect of short circuit current rise slope has been examined. With commercial power source it was produced no sound bead by instantaneous short circuit, long arc period and stubbing at welding speed 2.5mm/min Humping bead or undercut were showed by instantaneous short circuit and long arc period. Also, the weld bead was not formed during the long short circuit period after stubbing start and long arc extinguishment period after wire sticking by failure of arc regeneration, because the droplet was not transferred to weld pool. With increasing short circuit current rise slope the frequency of stubbing was decreased and the normal short circuit rate was increased. A control of short circuit current rise slope was effective factor in high speed welding.

• Journal of Welding and Joining
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• 제16권3호
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• pp.95-101
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• 1998

Waveforms of $CO_2$ gas shielded arc welding in short circuit transfer mode was studied with the waveform analysis program, which can calculate various waveform factors such as number of short circuit event, mean and standard deviation of short circuit time and arc time. The calculated values of these factors were correlated independently or in combination with the spatter generation rate to figure out the most reliable index for evaluating spatter generation and further for arc stability. As a result this study, it was confirmed that the spatter generation tends to decrease with the increase of short circuit frequency. Further to this, it was also found that as the short circuit frequency increases the short circuit event becomes more uniform resulting in the decrease of standard deviations ($\sigma$values) of short circuit time and arc time. This result demonstrated that these factors are strongly correlated with each other and thus any one of these factors can be used for the evaluation index. In the discussion, however, short circuit frequency was proposed for the most practical index in evaluating the arc stability of short circuit transfer mode since it is the one which could be monitored in-process condition without any complex caculation process.

• 한국의류학회지
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• 제45권1호
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• pp.200-216
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• 2021

This article considers short-form fashion videos as distinguished from fashion films, defines the concept, details the expressive characteristics of short-form fashion video, and reveals the method of producing it. For the methodology, a literature review was conducted to derive the concept and expression techniques. A case study was also performed to define the expressive characteristics. Five short-form fashion videos were also produced based on the results. The final results are as follows. First, short-form fashion video was defined as a fashion medium on the purpose of fashion communication within 60 seconds and classified by three digital image formats. Second, the result of analyzing the expression of the short-form fashion video shows the simplicity and reconstitution, characterization and remediation, borderless and expansion, and synesthesia trigger of the fashion image. Third, five short-form fashion videos were produced based on the theme of the digital garden. It shows that the short-form fashion video intensively expresses the content as a medium whose sensational expression is more prominent than the composition of the story by the short running time that reflects the taste of digital mainstream.

• ETRI Journal
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• 제9권1호
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• pp.118-124
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• 1987

Short channel n-MOSFET의 드레인-소오스 사이의 breakdown은 단순한 접합 breakdown이 아닌 avalanche-induced breakdown으로 p-MOSFET, long channel n-MOSFET의 breakdown 전압보다 훨씬 작은 값을 갖는다. Short channel n-MOSFET의 breakdown의 특징은 current-controlled 부저항 특성(snapback)이 나타나고, 게이트 전압에 따라 breakdown 전압보다 작은 sustainning 전압이 존재한다. 이와 같은 sustainning 전압은 short channel n-MOSFET의 안정한 동작에 또 하나의 제한 요소가 될 수 있다. 따라서 공정 및 회로 시뮬레이션을 위해, short channel n-MOSFET의 avalanche breakdown 현상에 대한 정확한 분석이 요구된다. Short channel n -MOSFET의 avalanche breakdown 현상을 분석하기 위해서Parasitic bipolar transistor를 도입한 분석적 모델을 이용하였다.

• 한국안전학회지
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• 제9권1호
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• pp.161-164
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• 1994

Computer aided unloading elastic compliance method was employed to measure the closure and the length of short cracks. The most significant factor that influences the fatigue growth behavior of short cracks is the crack closure Phenomenon. dc/dN-$\Delta$ $K_{eff}$ relationships of short cracks are found to coincide well with the corresponding long crack relationships. Non-propagating behavior of short cracks at notch root can be predicted from the crack opening SIF of short cracks, $K_{op}$ , and the growth equation of long cracks in Region I and II.n Region I and II.I.

• 음성과학
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• 제15권2호
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• pp.119-129
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• 2008

The purpose of this study were to develop short form versions of MacArthur-Bates Communicative Development Inventories - Korean and to discuss clinical implications. Two short versions were developed: one for $9\sim17$ month-olds(including 69 words and 17 object manipulation skills) and the other for $18\sim35$ month-olds (including 128 words and 5 grammatical items). Short versions seemed to be representative of full versions and showed developmental validity. Short versions showed concomitant validity with SELSI which is a standardized test for Korean children under 37 month-olds. Norm tables for words and criteria for object manipulation and grammaticality are also provided. M-B CDI-K short versions could be used as a preliminary screening tool to identify Korean children with language impairment economically and efficiently. Cautions using short versions of M-B CDI-K are discussed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.735-736
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• 2008

There are many equipments for the Short Circuit Test, for example Short Circuit Generator, Induction Motor, Sequence Timer, CLR, Back Up Breaker, Making Switch and Excitation Equipment etc. Gradually an allowable tolerance of the short circuit test voltage is become smaller by the standards for short circuit test. The excitation equipment of short circuit generator is very important for test voltage is adjusted by the excitation equipment. Especially the excitation equipment must be possessed character of exactitude, durability and inalterability because some times around 10,000 times opening and closing short circuit test is requested by clint, which must be done within one minute. The purpose of this study for function and operation of the excitation equipment which rated DC voltage is 1,000V, rated DC current is 300A, rated out put is 30kW and type is YNEX 97S-441/609, is to help operation of short circuit generator.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.866-867
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• 2008

Among many tests to verify the characteristics of power system apparatus, the short circuit test is performed to verify the performance characteristics of the apparatus under the short-circuited power system. The verification of the short-circuit performance is inevitable for the reliability of power system and the safety of the operator around. The short circuit performance test requires the suitable power source and Korea Electrotechnology Research Institute has 4000 MVA, 500 MVA short circuit generators for the short circuit performance test. This paper will study on the parameters of short-circuit generator and the estimation of them.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.79-84
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• 2000

Crack closure and growth behavior of physically short fatigue cracks under random loading are Investigated by performing narrow- and wide-band random loading tests for various stress ratios. Artificially prepared two-dimensional, short through-thickness cracks are used. The closure behavior of short cracks under random loading is discussed, comparing with that of short cracks under constant-amplitude loading and also that of long cracks under random loading. Irrespective of random loading spectrum or block length, the crack opening load of short cracks is much lower under random loading than under constant-amplitude loading corresponding to the largest load cycle in a random load history, contrary to the behavior of long cracks that the crack opening load under random loading is nearly the same as or slightly higher than constant-amplitude results. This result indicates that the largest load cycle in a random load history has an effect to enhance crack opening of short cracks.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 춘계종합학술대회
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• pp.288-292
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• 2002

RF 회로에 적합한 새로운 형태의 on-chip ESD protection 방법을 제시하였다. RF 회로의 특성을 이용하여 DC blocking capacitor 앞에 short-circuited stub를 달아서 ESD 소자로 활용하였다. 특히 short-circuited stub를 매칭 회로의 일부로 사용하여 stub의 길이를 줄일 수 있다. 또한 short-circuited stub의 width와 metal의 성분으로 ESD threshold voltage를 쉽게 예측 가능하다. 기존의 ESD 방지 회로와 달리 RF 회로를 위한 ESD 방지 회로에서 문제시되던 기생 capacitance 성분에 대한 문제점을 해결 할 수 있었다.