• Computers and Concrete
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• 제25권6호
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• pp.575-585
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• 2020

Based on a refined shear deformation finite strip, transient vibrations of graphene oxide powder (GOP) reinforced plates due to external pulse loads have been investigated. The plate has uniformly and linearly distributed GOPs inside material structure. Applied pulse loads have been selected as sinusoidal, linear and blast types. Such pulse loads result in transient vibrations of the GOP-reinforced plates which are not explored before. Finite strip method (FSM) has been performed for solving the equations of motion and then inverse Laplace transform technique has been employed to derive transient responses due to pulse loading. It is reported in this study that the transient responses of GOP-reinforced plates are dependent on GOP dispersions, GOP volume fraction, type of pulse loading, loading time and load locations.

• International Journal of Concrete Structures and Materials
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• 제1권1호
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• pp.83-88
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• 2007

This paper discusses a method of measuring transient potential response of a corrosion interface to a small galvanostatic pulse perturbation for a rapid assessment of the corrosion rate of reinforcing steel in concrete structures. Measurements were taken on 100 mm sections of steel bars which were subjected to a wide range of corrosion conditions, from passive steel to actively corroding steel. The duration of the applied galvanostatic pulse was varied between 5s and 180s, and the lateral distance of the point of measurement on the steel bar varied from zero to 400 mm. The result of the electrochemical transient response was investigated using a typical sampling rate of 1 kHz. Analysis of the transient potential response to the applied galvanostatic pulse has enabled the separation of equivalent electronic components so that the components of a series of capacitances and resistances, whose values are dependent on the corrosion condition of the reinforcing steel, could be isolated. The corrosion rate was calculated from a summation of the separate resistive components, which were associated with the corrosion interface, and was compared with the corrosion rate obtained from linear polarization resistance (LPR) method. The results show that the galvanostatic pulse transient technique enables the components of the polarization resistance to be evaluated separately so as to give more reliable corrosion rate values than those obtained from the LPR method. Additionally, this paper shows how the galvanostatic pulse transient response technique can be implemented. An appropriate measurement time for passive and actively corroding reinforcing steel is suggested for the galvanostatic pulse transient response measurements in the field site.

• 한국광학회지
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• 제2권4호
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• pp.209-213
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• 1991

최근들어 극초단 광학펄스를 생성하고 증폭하는 기술의 발달로 인하여 시분해 레이저 분광학에 많은 영향을 끼치게 되었다. 그 중에서도 응용성이 넓은 순간흡수분광학장치를 본 연구실에서 개발하였다. 이 기술은 고출력 레이저 펄스를 이용하여 white light continuum pulse를 생성시켜 이를 조사빔으로 이용하고, pump pulse는 원래 상태의 레이저를 이용하는 것이다. 순간흡수율 변화를 여러 파장에서 측정가능하도록 photodiode array를 이용하였으며, pump와 probe pulse의 시간차이에 의한 순간흡수율 변화를 색소의 일종인 DDI를 이용하여 측정하였다.

• 전기학회논문지
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• 제59권9호
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• pp.1611-1614
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• 2010

The explosion of a nuclear weapon radiates a gamma-ray in the form of a transient pulse. If the gamma-ray introduces to semiconductor devices, much Electron-Hole Pairs(EHPs) are generated in depletion region of the devices[7]. as a consequence of that, high photocurrent is created and causes upset, latchup and burnout of semiconductor devices[8]. This phenomenon is known for Transient Radiation Effects on Electronics(TREE), also called dose-rate effects. In this paper 3D structure of inverter and NAND gate device was designed and transient pulse gamma-ray was modeled. So simulation for transient radiation effect on inverter and NAND gate was accomplished and mechanism for upset and latchup was analyzed.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2000년도 추계종합학술대회
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• pp.568-572
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• 2000

This paper describes the experimental results of a transient impedance characteristics of grounding rods to a square pulse and standard lightning impulse current. The test were performed on single grounding rod($\phi$ 10mm, 1m) and triple-grounding rods( $\phi$ 10mm, 1m) of equilateral triangles with 5m spacing. For measurements of transient impedance, a pulse generator which can produce square wave of 30ns rise time and 20U Pulse duration was designed and fabricated. In the experiment, transient impedance of the grounding systems have been investigated from the recorded potential and current waveforms. The results showed that the value of the transient impedance is quite higher than the stationary resistance, and provide useful information for the value of a grounding system considered transient characteristics under a high frequency condition such as lightning stokes and ground-fault.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.1185-1186
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• 2008

A nuclear explosion emits a transient radiation pulse like gamma rays. Gamma rays have a high energy and cause unexpected effects in semiconductor devices. These effects are mainly referred to dose-rate latcup and dose-rate upset. By transient radiation pulse in CMOS devices, dose-rate latchup is simulated in this paper.

• International Journal of Air-Conditioning and Refrigeration
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• 제10권1호
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• pp.1-9
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• 2002

Effects of temperature coefficients fur dielectric constants on transient reflectances and thermal responses have been investigated for a metal(gold) thin-film during ultrashort pulse laser heating. Heating processes are simulated using the conventional conduction model(parabolic one-step, POS), the parabolic tow-step model(PTS), the hyperbolic two-step model(HTS). Results fro the HTS model are very similar to those from the PTS model, since the laser heating time in this study is considerably greater than the electron relaxation time. PTS and HTS models, however, result in completely different temperature profiles from those obtained by the POS model due to slow electron-lattice interactions compared to laser pulse duration. Transient reflectances are directly estimated from the linear relationship between electron temperature and complex dielectric constants, while conventional approaches assume that the change in reflectances is proportional to that in temperatuer. Reflectances at the front surface vary considerably for various dielectric constants, while those at the rear surface remain unchanged relatively.

• 한국소음진동공학회논문집
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• 제24권10호
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• pp.788-794
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• 2014

In this paper, the transient response analysis of the trapezoidal corrugated plate subjected to the pulse load is investigated by the theoretical method. Three types of pulse loads are considered: stepped, isosceles triangular and right triangular pulse loads. The corrugated plates can be represented as an orthotropic plate. Both the effective extensional and flexural stiffness of this equivalent orthotropic plate are considered in the analysis. The plate is stiffened by concentric stiffeners perpendicular to the corrugation direction. The stiffening effect is represented by the discrete stiffener theory. This theoretical results are validated by those obtained from 3D finite element analysis based on shell elements. Some numerical results are presented to check the effect of the geometric properties.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1864-1866
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• 1996

Grounding is the art of making an electrical connection to the earth. In order to protect man, electrical and/or electric equipments from the lightning strokes, all the energy of lightning strokes must be diverted via a safe path to earth. It is essential to the transient grounding resistance against lightning strokes. In this paper, measurements and analyses of grounding surge impedance have been investigated. For measurements of grounding surge impedance the pulse generator was designed and fabricated. The pulse generator has rise time of 22.4 ns and pulse duration of $8\;{\mu}s$. The transient grounding resistance has been measuring by injecting low power and step current between the earthing system under test and a remote reference earth and measuring the potential rise caused by this current. As a result, the transient grounding resistance against lightning surge in the short time domain is much higher than steady state grounding resistance.

• 전기학회논문지P
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• 제61권3호
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• pp.134-139
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• 2012

The power characteristics of the Mg-Air fuel cell were investigated with regard to variation of load conditions. The types of load current using for the Mg-Air fuel cell with 10% NaCl electrolyte were step type, ramp type and pulse type. It was found that transient phenomena occurred in the step current load, which is due to activate of the oxidation-reduction reaction process. And the transient time increase with the load current increase. In the load current of ramp type, the slop of voltage drop increased with current load slop ${\alpha}$ increase. The load voltage and power decreased according to the pulse period of load current decrease were attributed to the metal sludges.