• 오토저널
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• 제5권3호
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• pp.24-32
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• 1983

전기 동저항 제어실험을 통해 다음과 같은 결론을 얻었다. (1) 점용접 과정에서 동 저항이 용접질(용접강도)을 잘 나타내 준다. 1) 동저항 곡선의 peak가 발생하는 시간이 이르면 일반적으로 늦게 나타난 것보다 용접질이 좋다. (단, expulsion이 발생하지 않을 때까지). 2) peak에서의 저항값과 용접시간 끝에서의 저항값 차이가 클수록 일반적으로 용접질이 좋다. (2) 한 동 저항곡선에 다른 동 저항곡선을 맞추려는 제어를 할 때는 다음과 같은 관계가 있다. 1) P-control로는 동저항을 추적하는 효과를 충분히 얻을 수 없고 적분제어기를 추가한 PI-control을 하면 잘 추적한다. 2) 용접질의 관점으로 볼 때 원하는 용접강도를 얻으려고 PI제어를 하면 그 용접 평균강도에 아주 근사한 강도를 얻을 수 있다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2008년도 춘계학술발표대회 개요집
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• pp.36-36
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• 2008

• 한국정밀공학회지
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• 제33권11호
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• pp.937-941
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• 2016

Stand-alone cervical cage consists of a PEEK body, Ti plate, and screw, which are configured as a single-piece. Through a single operation, this implantable medical device is capable of completely fixing the cervical vertebral body. For example, instead of a plate, which is normally used, the intervertebral disc is removed and replaced with a cervical cage. It should be noted that in Korea, KFDA guidelines for a stand-alone cervical cage have not yet been suggested. Therefore, the aim of this study is to present the systematic study of the static compression test, static torsion test, dynamic compression test, and expulsion test. Further, the test method is designed to refer to the ASTM standard and relative literature.

• Journal of Welding and Joining
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• 제12권3호
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• pp.56-62
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• 1994

The spot weldability of high strength steel sheet and two stories galvannealed high strength steel sheet has been studied. 1) Tensile shear strength decreased inversely as welding current increased over 12KA in the case of two stories galvannealed high strength steel sheet. 2) When heat flux input over 12KA, hardening region become narrow in case of two stories galvannealed high strength steel sheet. 3) The size of hardening region affect the strength of nuggets.

• Journal of Welding and Joining
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• 제14권3호
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• pp.41-47
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• 1996

The spot weldability of coated steels for automobile has been investigated. Coated steels of SPC-Zn DC, SPC Zn-Ni SC, SPC Zn-Ni DC, SPC Zn-Fe DC and OCCS were welded under different conditions of welding current, force and time. Coating thickness at the welded surface was reduced as increased welding current. Tensile shear strength(TSS) and cross tensile strength (CTS) were increased up to expulsion began, then dropped as increased current. Optimum conditions of welding force and time were different, however 200~250kgf and 15~20cycle were optimum for coated SPC (Steel Plate Cold). Weldability lobes were measured for each coated steel and they showed narrow range of working welding current. The organic composite coated steel (OCCS) had the highest current to get $\sqrt5{t}$ nugget size and narrowest working welding current range.

• 한국정밀공학회지
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• 제24권4호
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• pp.147-152
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• 2007

UV laser ablation of polyimide is a combination of photochemical and photothermal mechanism. Photochemical mechanism is that molecular bonds are broken by photon energy and photothermal is evaporation and melt expulsion. When the laser processing, the etching depth needs to be calculated for prediction of processing result. In this paper, in order to predict the laser etching depth of polyimide by UV laser with the wavelength of 355nm, the theoretical model which includes both the photothermal and the photochemical effect was introduced. The model parameters were obtained by comparing with experimental results. The 3rd harmonic $Nd:YVO_4$ laser system was used in the experiment. From these experimental and theoretical results, the laser ablation of a polyimide was verified to achieve the highest quality microstructure.

• Bulletin of the Korean Chemical Society
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• 제34권11호
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• pp.3372-3376
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• 2013

The kinetic studies on the reactions of ethyl methyl (2) and ethyl propyl (4) chlorothiophosphates with X-pyridines have been carried out in acetonitrile at $35.0^{\circ}C$. The free energy correlations with X show biphasic concave upwards with a break point at X = H (2) and 3-Ph (4), respectively. A stepwise mechanism with a rate-limiting leaving group expulsion from the intermediate is proposed based on the magnitudes of selectivity parameters for both substrates. The considerably large values of ${\beta}_X$ = 1.50(2) and 1.44(4) with strongly basic pyridines and relatively small values of ${\beta}_X$ = 0.43(2) and 0.36(4) with weakly basic pyridines are interpreted as a change of the attacking direction of the X-pyridines from a frontside to a backside attack toward the chloride leaving group.

• 한국군사과학기술학회지
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• 제7권2호
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• pp.41-47
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• 2004

In this paper, simulations of the underwater discharge system with compressed air are performed to predict dynamic characteristics of the system and to find optimal opening trajectories of the expulsion valve. Major components of the system are defined and their governing equations are derived to make up the mathematical model. The compressed air discharge method is affected largely by the discharge depth, and therefore the opening trajectories according to the discharge depth should be found to satisfy the demands of discharge performances. Simulation results are compared with experimental data to confirm the validity of the system model.

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2260-2264
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• 2012

The kinetics and mechanism of the pyridinolysis ($XC_5H_4N$) of dimethyl isothiocyanophosphate are investigated in acetonitrile at $55.0^{\circ}C$. The Hammett and Br$\ddot{o}$nsted plots for substituent X variations in the nucleophiles exhibit two discrete slopes with a break region between X = 3-Ac and 4-Ac. These are interpreted to indicate a mechanistic change at the break region from a concerted to a stepwise mechanism with a rate-limiting expulsion of the isothiocyanate leaving group from the intermediate. The relatively large ${\beta}x$ values imply much greater fraction of frontside nucleophilic attack TSf than that of backside attack TSb. The steric effects of the two ligands play an important role to determine the pyridinolysis rates of isothiocyanophosphates.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.800-802
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• 2004

When an accident is happen due to using a bad Wire Compressor, some public resentments are caused and It cause lawsuit for we. In case, we will undergo a colossal financial loss. in addition to, Guide to improve quality of operation by using the number of times of pressing and pressing pressure with cooperative private enterprise. And because of needs for Thermal, Electrical and Chemical factor analysis of connection point of sleeve, expect to try improving problems of wire presser whole our company. We expect that reduce fault and save cost by this process. Consequently, we will prevent power losing and black out due to line faults by expulsion of inferiority equipment and prevent heating and line fault. This is possible using Alarming and Auto Locking Wire Compressor that is improve on this study.