• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2075-2083
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• 2021

The article provides a review of the research results obtained during of more than 20 years concerning using the gaseous radiochemical method (GRCM) for detecting of ionizing radiation. This method based on threshold nuclear reactions with production of radioactive noble gas which does not interact with the materials of gaseous tract. The applications of GRCM in the diagnostics of neutrinos, neutrons, charged particles, thermonuclear plasma thermometry, and the study of the structure and dynamics of astrophysical objects, position-sensitive dosimetry of neutron targets with accelerator driving, spatial distribution of the fast neutron flux density in a nuclear reactor allowing the transformation of longitudinal coordinate of neutron flux distribution into a temporal distribution of the radiochemical gas decay counting rate ("barcode" semblance) and measurement of bombarding particles spectra are described. Experimental testing of the described technologies was made on the neutron target driven with the linear proton accelerator of Institute for Nuclear Research of Russian Academy of Sciences (INR RAS).

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.143.1-143.1
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• 2015

An inductively coupled plasma source driven by 13.56MHz was prepared for the deposition of a-C:H thin film. Properties of the plasma source are investigated by fluid simulation including Navier-Stokes equations and home-made tuned single Langmuir probe. Signal attenuation ratios of the Langmuir probe at first and second harmonic frequency were 13.56Mhz and 27.12Mhz respectively. Dependencies of plasma parameters on process parameters were agreed with simulation results. Ar/CH4 plasma simulation results shown that hydrocarbon radical densities have their lowest value at the vicinity of gas feeding line due to high flow velocity. For input power density of 0.07W/cm3, CH radical density qualitatively follows electron density distribution. On the other hand, central region of the chamber become deficient in CH3 radical due to high dissociation rate accompanied with high electron density. The result suggest that optimization of discharge power is important for controlling deposition film quality in high density plasma sources.

• YAKHAK HOEJI
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• v.44 no.3
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• pp.245-250
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• 2000

Because nonsteroidal anti-inflammatory drugs are reported to cause fluid retention and hypertension by inhibition of prostaglandin synthesis, the effects of piroxicam on pharmacodynamics and pharmacokinetics of nifedipine were studied in male spontaneously hypertensive rats. They received nifedipine (0.5 mg/kg) alone or combined with piroxicam (5 mg/kg) intravenously. Plasma levels norepinephrine, an index of sympathetic stimulation, were measured prior to each treatment and 5 min after drug administration. Changes in blood pressure were examined serially and blood samples for analysis of nifedipine were also taken for 6 hr following drug administration. Plasma nifedipine concentration were assayed by HPLC and pharmacokinetic parameters were calculated. Blood pressure was reduced (p<0.01), but plasma norepinephrine level was increased (p<0.05) by nifedipine administration. Anti-hypertensive effect of nifedipine was potentiated (p<0.05) by piroxicam coadministration, but effect of nifedipine on plasma norepinephrine level was not affected. In case of rats received nifedipine and piroxicam, plasma nifedipine concentrations were higher (p<0.05) than those from rats received nifedipine alone at 2,3,4,5 and 6 hours following drug administration. The area under the plasma concentration vs. time curve was increased (p<0.05), while the elimination rate constant was decreased (p<0.01) by piroxicam coadministration. No significant differences were observed in the plasma clearance, apparent volume of distribution and elimination half-life. Thus, piroxicam not only potentiated antihypertensive effect of nifedipine, but also altered nifedipine pharmacokinetics in the rats. It is concluded that the potentiation of nifedipine antihypertensive effect might correlate with the increment of its plasma concentration by piroxicam coadministration.

• Journal of the Korean Society of Industry Convergence
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• v.6 no.4
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• pp.269-275
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• 2003

A non-thermal plasma process combined with $Cr_2O_3/TiO_2$ catalyst was applied to the decomposition of trichloroethylene (TCE). A dielectric barrier discharge reactor operated with AC high voltage was used as the non-thermal plasma reactor. The effects of reaction temperature and input power on the decomposition of TCE and the formation of byproducts including HCl, $Cl_2$, CO, NO, $NO_2$ and $O_3$ were examined. At an identical input power, the increase in the reaction temperature from 373 K to 473 K decreased the decomposition of TCE in the plasma reactor. The presence of the catalyst downstream the plasma reactor not only enhanced the decomposition of TCE but also affected the distribution of byproducts, significantly. However, synergistic effect as a result of the combination of non-thermal plasma with catalyst was not observed, i.e., the TCE decomposition efficiency in this plasma-catalyst combination system was almost similar to the sum of those obtained with each process.

• Journal of the Korean institute of surface engineering
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• v.41 no.4
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• pp.134-141
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• 2008

We have developed a numerical model for a remote ICP(inductively coupled plasma) system in 2D and 3D with gas distribution configurations and confirmed it by plasma diagnostics. The ICP source has a Cu tube antenna wound along a quartz tube driven by a variable frequency rf power source($1.9{\sim}3.2$ MHz) for fast tuning without resort to motor driven variable capacitors. We investigated what conditions should be met to make the plasma remotely localized within the quartz tube region without charged particles' diffusing down to a substrate which is 300 mm below the source, using the numerical model. OES(optical emission spectroscopy), Langmuir probe measurements, and thermocouple measurement were used to verify it. To maintain ion current density at the substrate less than 0.1 $mA/cm^2$, two requirements were found to be necessary; higher gas pressure than 100 mTorr and smaller rf power than 1 kW for Ar.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.136-147
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• 1993

The paper describes : ⅰ) Mathematical modeling of poloidal flux to define and calculate the tokamak plasma position based on a property of the plasma boundary which is always a flux surface. Controlling the plasma boundary position is therefore equivalent to equalizing the flux value on several points belonging to a curve tangent to the limiter. ⅱ) Experimental method for determining the outmost poloidal isoflux surface by a linear combination of measurements of magnetic fluxes, fields and field gradients, without requiring knowledge of internal plasma parameters for the feedback control, i.e., with neither corrections for variation in the poloidal beta and the plasma current distribution, nor compensations for the induced currents in the vacuum vessel. ⅲ) Feedback control algorithm for the regulation of plasma boundary position and its electronics hardware based on the PID control theory. ⅳ) Experimental results obtained from the RTP tokamak experiments using the present plasma control system.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1817-1819
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• 2004

From the plasma application point of view, electron temperature and density are one of the most important parameters for plasma process. But it is only available to control plasma by adjusting external factors like gas pressure and input power. In this paper, pulse-modulated plasma is generated by modulating 13.56GHz RF power with 1, 5, 10kHz pulse. And Langmuir probe technique is used to study the distribution of electron temperature and density. When modulated pulse is off, electron temperature decreases gradually in form of exponential decay. The value t of exponential decay slope is 33.619, 13.834, 10.803 in 1kHz. 5kHz. 10kHz. This implies that this method can be used to control electron temperature and density.

• Nutrition Research and Practice
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• v.2 no.1
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• pp.17-21
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• 2008

Aloin is a physiologically active anthraquinone present in aloe. There are two isomers of aloin, aloin A and aloin B, occurring as a mixture of diastereomers. The objective of this study was to determine the bioavailability and tissue distribution of aloin. Rats were gavaged with 11.8g/kg aloin, and the levels of aloin and its conjugates were measured in plasma, tissues, and urine. Plasma aloin level showed a peak at 1hr after the administration and the concentration was $59.07{\pm}10.5\;ng/ml$. The 24 h cumulated urinary aloin was 0.03% of the initial dose. These results suggest that aloin is absorbed and reaches a peak plasma level within 1-1.5 h after the administration and a significant portion is possibly metabolized or is excreted in feces. These results can apply to the determination of the adequate intake level of aloe and aloe products to achieve the desired biological effect, and to interprete in vitro study results.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.282-285
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• 2000

Four helical resonators are distributed in a 2 ${\times}$ 2 array by modifying upper part of the conventional reactive ion etching(RIE) type LCD etcher in order to prepare a large area plasma source. Since the resonance condition of the RF signal to the helical antenna, one RF power supply is used for delivering the power efficiently to all four helical resonators without an impedance matching network Previous work of 2 ${\times}$ 2array inductively coupled plasma(ICP)requires one matching circuit to each ICP antenna for more efficient power deliverly Distributions of ion density and electron temperature are measured in terms of chamber pressure, gas flow rate and RF power . By adjusting the power distribution among the four helical resonator units, argon plasma density of higher than 10$\^$17/㎥ with the uniformity of better than 7％ can be obtained in the 620 ${\times}$ 620$\textrm{mm}^2$ chamber.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.419-422
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• 1991

A mathematical model was developed to predict the temperature, the density, and the velocity distribution of an inductively coupled thermal plasma. It was for an atmospheric pressure argon thermal plasma generated by a 4 MHz radio frequency power. It has been shown that the hottest region can be moved toward centrial region by applying an external magnetic field. Based on the results of the simulation. an ICP(Inductively Coupled thermal Plasma) system was constructed and thermal plasma was generated.