• 대한전자공학회논문지SD
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• 제37권12호
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• pp.29-34
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• 2000

금속유도 측면 결정화에 의해 제작된 다결정 실리콘 박막 트랜지스터(Thin Film Transistor; TFT)의 전기적 스트레스의 효과에 대해 연구하였다. MILC로 제작된 TFT에 전기적 스트레스가 인가될 때, off-state 전류가 100배에서 10000배까지 감소한다. 그러나 전기적 스트레스를 인가한 소자를 관상로에서 열처리를 할 경우 열처리온도가 증가할 수록 off-state 전류가 다시 증가했다. 열처리온도에 따른 off-state 전류의 의존성으로부터 MILC 다결정 실리콘 박막내 트랩준위의 활성화에너지(0.34eV)를 얻어냈다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 춘계학술발표대회 논문집
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• pp.76-79
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• 2000

Polymeric composites exhibit highly nonlinear and rate dependent behavior during loading and unloading in off-axis directions. The equilibrium state of stress during loading is lower than the state of stress produced at finite strain rates. The amount of stress relaxation during loading decreases. Interestingly, however, the stress goes up to reach to the equilibrium state of stress for a fixed displacement during unloading. The unloading behavior is quite similar to the loading behavior. The stress relaxation patterns during loading and unloading is also similar, and those depend on the fiber orientation angles and the loading and unloading rates. The AS4/PEEK thermoplastic composite is used to characterize the relaxation behavior for different off-axis angles and loading rates. There exists a transient loading region at the beginning of unloading. The effective stress and effective plastic strain concept is used to establish a master curve of stress recovery pattern for different off-axis angles and unloading rates.

• 한국전기전자재료학회논문지
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• 제31권6호
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• pp.372-376
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• 2018

The effects of off-state bias stress on the characteristics of p-type poly-Si TFT were investigated. To reduce the gate-induced drain leakage (GIDL) current, the off-state bias stress was changed by varying Vgs and Vds. After application of the off-state bias stress, the Vgs causing GIDL current was dramatically increased from 1 to 10 V, and thus, the Vgs margin to turn off the TFT was improved. The on-current and subthreshold swing in the aged TFT was maintained. We performed a technology computer-aided design (TCAD) simulation to describe the aged characteristics. The aged-transfer characteristics were well described by the local charge trapping. The activation energy of the GIDL current was measured for the pristine and aged characteristics. The reduced GIDL current was mainly a thermionic field-emission current.

• 한국정밀공학회지
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• 제5권1호
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• pp.71-77
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• 1988

This study applies dynamic deformation analysis to the rake face stress distribution of cemented carbide cut-off tools by turning, using a finite element method. The results are following: 1. The dynamic loaded state of a cut-off tool was very changeable for the first 0.6 seconds. Reaching the normal state, it became in active. 2. Chipping was influnced not only by the magnitude of stress but also by the abrupt change of tensile and compressive stresses. 3. The distribution chat of principal stress by dynamic load and the direction of resultant vector were almost constant regardless of load time.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.209-212
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• 2004

In this paper, The stress induced leakage currents of thin silicon oxides is investigated in the nano scale structure implementation for Soc. The stress and transient currents associated with the on and off time of applied voltage were used to measure the distribution of high voltage stress induced traps in thin silicon oxide films. The stress and transient currents were due to the charging and discharging of traps generated by high stress voltage in the silicon oxides. The channel current for the thickness dependence of stress current, transient current, and stress induced leakage currents has been measured in oxides with thicknesses between $41\square\;and\;113.4\square,$ which have the channel width x length 10x1um, respectively. The stress induced leakage currents will affect data retention and the stress current, transient current is used to estimate to fundamental limitations on oxide thicknesses. The weight value of synapse transistor was caused by the bias conditions. Excitatory state and inhitory state according to weighted values affected the channel current. The stress induced leakage currents affected excitatory state and inhitory state.

• Journal of Power Electronics
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• 제19권2호
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• pp.353-362
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• 2019

To address the problem of circulating current loss in the traditional zero-current switching (ZCS) full-bridge (FB) DC/DC converter, a ZCS FB DC/DC converter topology and modulation strategy is proposed in this paper. The strategy can achieve ZCS turn on and zero-voltage and zero-current switching (ZVZCS) turn off for the primary switches and realize ZVZCS turn on and zero-voltage switching (ZVS) turn off for the auxiliary switches. Moreover, its resonant circuit power is small. Compared with the traditional phase shift full-bridge converter, the new converter decreases circulating current loss and does not increase the current stress of the primary switches and the voltage stress of the rectifier diodes. The diodes turn off naturally when the current decreases to zero. Thus, neither reverse recovery current nor loss on diodes occurs. In this paper, we analyzed the operating principle, steady-state characteristics and soft-switching conditions and range of the converter in detail. A 740 V/1 kW, 100 kHz experimental prototype was established, verifying the effectiveness of the converter through experimental results.

• 대한기계학회논문집B
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• 제28권8호
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• pp.902-909
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• 2004

A steady-state Reynolds averaged Navier-Stokes simulation was conducted to investigate the distribution of the Reynolds stress tensor inside tip leakage vortex of a linear compressor cascade. Two different inlet flow angles ${\beta}=29.3^{\circ}$(design condition) and $36.5^{\circ}$(off-design condition) at a constant tip clearance size of $1\%$ blade span were considered. Classical methods of solid mechanics, applied to view the Reynolds stress tensor in the principal direction system, clearly showed that the high anisotropic feature of turbulent flow field was dominant at the outer part of tip leakage vortex near the suction side of the blade and endwall flow separation region, whereas a nearly isotropic turbulence was found at the center of tip leakage vortex. There was no significant difference in the anisotropy of the Reynolds normal stresses inside tip leakage vortex between the design and off-design condition.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.33-35
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• 1995

Tubular coils are widely used in various electromagnetic applications. For the purpose to obtain the mechanical output power, one of the two sets of coil arrays, called drive, is generally fixed while the other, called sleeve or projectile, is not fixed and easy to move. Among the three force components acting on the coil arrays, the radial one used to affect as a stress on the surfiace of the sleeve, or a restoring force if it is off-centered. The system under transient state or intended pulsed input power is likely to have the worst condition in mechanical stress, and it is necessary to design the mechanical strength of the sleeve within the permanent deformation limit. This paper is focused on the presentation of analytic expressions for the stress on surface of the sleeve.

• 턱관절균형의학회지
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• 제13권sup호
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• pp.1-8
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• 2023

Objectives: Parkinson's disease (PD) is currently the most rapidly increasing degenerative brain disease due to population aging and westernization of lifestyle. Levodopa is the most commonly used drug to manage PD symptoms. However, levodopa has a problem in that the wearing-off phenomenon occurs as the duration and dose of administration increase. In order to investigate the wearing-off phenomenon in PD patients and devise countermeasures, we conducted a questionnaire survey in Korea. Methods: For the study, a questionnaire with a total of seven items was prepared. Part IV of the MDS-UPDRS (Movement Disorder Society-Sponsored Revision of the Unified Parkinson's Disease Rating Scale) and the WOQ-9 (9-symptom Wearing-off Questionnaire) were used as references. Results: Of the 48 patients who completed the questionnaire, all 47 patients who completed the questionnaire experienced the wearing-off phenomenon. Only one of the patients diagnosed with PD a year ago did not experience the wearing-off phenomenon. Patients frequently mentioned a lack of sleep and stress as aggravating factors for wearing-off. They also stated that in order to resolve the off-state, they walked, massaged, warmed up the body, stretched and exercised. Conclusions: Because wearing-off is such a common occurrence, it is thought necessary to develop wearing-off prevention and resolution measures that PD patients can use in their daily lives.

• Geomechanics and Engineering
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• 제29권6호
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• pp.683-696
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• 2022

Dams are inevitably planned to be built on thick overburden with high permeability and deformability. The connection part between concrete cut-off wall in overburden and earth core in dam body is not only a key part of the anti-seepage system, but also a weak position. Large uneven settlement will be aroused at the concoction part. However, the interaction behavior and the scope of the connection part cannot be determined effectively. In this paper, numerical analysis of a high earth core dam built on thick overburden was carried out with large deformation FE method. The mechanical behavior of the connection part was detail studied. It can be drawn that there is little differences in dam integral deformation for different analysis method, but big differences were found at the connection part. The large deformation analysis method can reasonably describe the process that concrete wall penetrates into soil. The high plasticity clay has stronger ability to adapt to large uneven deformation which can reduce stress level, and stress state of concrete wall is also improved. The scope of high plasticity clay zone in the connection part can be determined according to stress level of soils and penetration depth of concrete wall.