• Rapid Communication in Photoscience
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• 제4권1호
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• pp.25-28
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• 2015

The time-resolved photoexcitation dynamics of electrical conductivity of the magnetic organic superconductor ${\lambda}-(BETS)_2Fe_{0.45}Ga_{0.55}Cl_4$ has been studied with a nanosecond visible laser pulse at its three different phases, i. e., metallic phase, superconducting phase and insulating phase. A transient increase of the resistance is induced by photoirradiation at all the temperatures measured for all three phases, but the decay profile shows a significant temperature dependence. The relaxation rate in the metallic and insulating phase are different from each other, and the decay time is relatively faster and almost constant in the metallic phase. However, a prolongation of the relaxation time is observed at temperature just around the narrow superconducting phase. Nonbolometric (nonthermal) origin of the observed photoresponse of the electrical conductivity is confirmed in the superconducting phase.

• Applied Microscopy
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• 제46권1호
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• pp.20-26
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• 2016

Our work on $Sc_2O_3-W$ matrix dispenser cathodes had been reviewed in this paper. The cathode with uniform distribution of $Sc_2O_3$ had been obtained using liquid-liquid doping method. The cathode had excellent emission property, i.e., the emission current density in pulse condition could reach over $35A/cm^2$. It was found that the cathode surface was covered by a Ba-Sc-O active substance multilayer with a thickness of about 100 nm, which was different from the monolayer and semiconducting layer in thickness. Furthermore, the observation results displayed that nanoparticles appeared at the growth steps and the surface of tungsten grains of the fully activated cathode. The calculation result indicated that the nanoparticles could cause the increase of local electric field strengths. We proposed the emission model that both the Ba-Sc-O multilayer and the nanoparticles distributing mainly on the growth steps of the W grains contributed to the emission. The future work on this cathode has been discussed.

• The Journal of the Acoustical Society of Korea
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• 제22권4E호
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• pp.167-175
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• 2003

Shear wave velocity was measured and grain size analysis was conducted on two core samples obtained in unconsolidated marine sediments of the western continental margin, the East Sea. A pulse transmission technique based on the Hamilton frame was used to measure shear wave velocity. Duomorph ceramic bender transducer-receiver elements were used to generate and detect shear waves in sediment samples. Time delay was calculated by changing the sample length from the transducer-receiver element. Time delay is 43.18 μs and shear wave velocity (22.49 m/s) is calculated from the slope of regression line. Shear wave velocities of station 1 and 2 range from 8.9 to 19.0 m/s and from 8.8 to 22 mis, respectively. Shear wave velocities with depth in both cores are qualitatively in agreement with the compared model〔1〕, although the absolute value is different. The sediment type of two core samples is mud (mean grain size, 8-9Φ). Shear wave velocity generally increases with sediment depth, which is suggesting normally consolidated sediments. The complicated variation of velocity anisotropy with depth at station 2 is probably responsible for sediment disturbance by possible gas effect.

• 대한기계학회논문집
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• 제12권1호
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• pp.152-162
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• 1988

본 연구에서는 열물성치 측정시 여러가지 어려운 수고를 가급적 줄이고 측정시간도 짧도록 하기 위해서 방평파 펄즈상가열법을 채용하여 이론적 검토와 고온에 유한원형인 시료로 부터 복사열손실을 최소화할 수 있는 방법을 고려하였다. 물론 시료는 전지회로의 용량소자, 콘텐서(condenser) 또는 전기절연이 주용도이며 유전율이 서로 다른 5종류의 세라믹 유전체에 관해서도 상온으로부터 약 1300k 까지 열물성치를 계측하였다. 특히 세라믹 유도체에는 유전율 및 기공율에 의한 열물성치가 가 다르기 때문에 그들사이의 관계에 대해서도 검토하였다.

• 대한의용생체공학회:의공학회지
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• 제18권1호
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• pp.17-24
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• 1997

We have developed a patient monitoring system including module-based bedside monitors, interbed network, central stations, clinical workstations, and DB servers. A bedside monitor with a color LCD can accommodate up to 3 module cases and 21 different modules. Six different physiological parameters of ECG, respiration, invasive blood pressure, noninvasive blood pressure, body temperature, and arterial pulse oximetry with plethysmoyaph are provided as parameter modules. In a single bedside monitor, modules and a module controller communicate with IMbps data rate through an intrabed network based on RS-485 and HDU protocol. At the same time, it communicates with other bedside monitors and central stations through interbed network based on 1 OMbps Ethernet and TCP/IP protocol. Central stations using 20" color CRT monitors can be connected with many bedside monitors and they display 18 channels of waveforms simultaneously. Clinical workstations are used mainly for the review of patient datE In order to accommodate more advanced data management capabilities such as 24-hour full disclosure, we have developed a relational database server dedicated to the patient monitoring system. Software for bedside monitor, central station, and clinical workstation fully utilizes graphical user interface techniques and all functions are controlled by a rotate/push button on the bedside monitor arid a mouse on the central station and clinical workstation. The entire system satisfies the requirements of AAMI and ANSI standards in terms of electrical safety and performances.nces.

• 조명전기설비학회논문지
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• 제15권1호
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• pp.28-35
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• 2001

이 논문에서는 형광램프를 광고판에 사용할 수 있도록 하기 위해 형광램프의 점멸 및 가변색 동작으로 제어할 수 있는 전자식 스타터와 제어장치를 개발하였다. 개발된 전자식 스타터는 제어장치의 점등신호에 따라 20∼40[W] 형광램프를 일반 점등시키며, 최소 0.2[s] 동안의 점멸 동작에서도 램프 수명을 3,000시간 이상 보장할 수 있다. 또한 마이크로컨트롤러로 구성된 제어장치는 최대 128개의 형광램프가 제어가능하고, 10가지 이상의 점멸모드와 3개의 RGB 형광램프를 이용하여 7가지 광색을 표현할 수 있는 가변색 모드가 가능하다.

• 전기학회논문지P
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• 제55권2호
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• pp.57-61
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• 2006

This paper calculates and gives the analysis of mean energy in pure $SiH_4,\;Ar-SiH_4$ mixture gases ($SiH_4-0.5[%],\;5[%]$) over the range of $E/N =0.01{\sim}300[Td]$, p = 0.1, 1, 5.0 [Torr] by Monte Carlo the Backward prolongation method of the Boltzmann equation using computer simulation without using expensive equipment. The results have been obtained by using the electron collision cross sections by TOF, PT, SST sampling, compared with the experimental data determined by the other author. It also proved the reliability of the electron collision cross sections and shows the practical values of computer simulation. The calculations of electron swarm parameters require the knowledge of several collision cross-sections of electron beam. Thus, published momentum transfer, ionization, vibration, attachment, electronic excitation, and dissociation cross-sections of electrons for $SiH_4$ and Ar, were used. The differences of the transport coefficients of electrons in $SiH_4$, mixtures of $SiH_4$ and Ar, have been explained by the deduced energy distribution functions for electrons and the complete collision cross-sections for electrons. A two-term approximation of the Boltzmann equation analysis and Monte Carlo simulation have been used to study electron transport coefficients.

• Journal of Power Electronics
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• 제19권2호
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• pp.475-486
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• 2019

This paper proposes the modulation and control of a three-to-six-phase matrix converter with an asymmetrical six-phase output. The matrix converter (MC) outputs consist of two sets of three-phase spatially shifted by $30^0$, where the two sets have two isolated neutrals. The space vector approach is considered for the modeling and subsequent modulation of the three-to-six phase MC. The intelligent selection of voltage space vectors is made to synthesize the reference voltages and to obtain a sinusoidal output. The dwell times of selected voltage space vectors are adjusted in such a way that the effect of the second and the third auxiliary plane vectors (i.e., x1-y1, and x2-y2) are nullified. To achieve the maximum output voltage gain and to ensure that no reactive power is drawn from the utility supply, the input side power factor is maintained at unity. Nevertheless, the source side power factor is controllable. The modulation technique is implemented in dSPACE working in conjunction with a FPGA. Hardware results that validate the proposed control algorithm are discussed.

• 대한전자공학회논문지
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• 제23권6호
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• pp.807-813
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• 1986

Measurements of interface states in a MOS capacitor by DLTS system using wideband monophase lock-in amplifier are discussed. A new signal analysis method that takes into account the bias pulse width and the gate off width is presented to remove the errors in the measured parameters of interface states resulting from the traditional method which neglects the effect of those widths. Theoretical calculations are made for the parameters related to the rate window, signal to noise ratio, and the energy resolution. On the grounds of this discussion, interface states of the MOS capacitor on p-type substrate of (110) orentation are measured with the optimal gate-off width with respect to the S/N ratio and the energy resolution. The results are interface state density of the order of 10**10 (cm-\ulcornereV**-1) to 10**11 (cm-\ulcornereV**-1) in the energy range of Ev+0.15(dV) to Ev+0.5(eV), and constant capture cross section of the order of 10**-16 (cm\ulcorner.

• 한국축산식품학회지
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• 제44권2호
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• pp.309-325
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• 2024

The consumption of meat has been increasing, leading to a dynamic meat and meat processing industry. To maintain the quality and safety of meat products, various technologies have been explored, including intense pulsed light (IPL) technology. Several factors affect the inactivation of microorganisms by IPL treatment, including light intensity (fluence), treatment duration, pulse frequency, and the distance between the lamp and the samples. Meat products have been studied for IPL treatment, resulting in microbial reductions of approximately 0.4-2.4 Log. There are also impacts on color, sensory attributes, and physico-chemical quality, depending on treatment conditions. Processed meat products like sausages and ham have shown microbial reductions of around 0.1-4 Log with IPL treatment. IPL treatment has minimal impact on color and lipid oxidation in these products. Egg products and dairy items can also benefit from IPL treatment, achieving microbial reductions of around 1-7.8 Log. The effect on product quality varies depending on the treatment conditions. IPL technology has shown promise in enhancing the safety and quality of various food products, including meat, processed meat, egg products, and dairy items. However, the research results on animal-based food are not diverse and fragmentary, this study discusses the future research direction and industrial application through a review of these researches.