• 한국의학물리학회지:의학물리
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• 제33권4호
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• pp.108-113
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• 2022

Purpose: Proton therapy has been used for optimal cancer treatment by adapting its Bragg-peak characteristics. Recently, a tissue-sparing effect was introduced in ultrahigh-dose-rate (FLASH) radiation; the high-energy transmission proton beam is considered in proton FLASH therapy. In measuring high-energy/ultrahigh-dose-rate proton beam, Faraday Cup is considered as a dose-rate-independent measurement device, which has been widely studied. In this paper, the feasibility of the simply designed Faraday Cup (Poor Man's Faraday Cup, PMFC) for transmission proton FLASH therapy is investigated. Methods: In general, Faraday cups were used in the measurement of charged particles. The simply designed Faraday Cup and Advanced Markus ion chamber were used for high-energy proton beam measurement in this study. Results: The PMFC shows an acceptable performance, including accuracy in general dosimetric tests. The PMFC has a linear response to the dose and dose rate. The proton fluence was decreased with the increase of depth until the depth was near the proton beam range. Regarding secondary particles backscatter from PMFC, the effect was negligible. Conclusions: In this study, we performed an experiment to investigate the feasibility of PMFC for measuring high-energy proton beams. The PMFC can be used as a beam stopper and secondary monitoring system for transmission proton beam FLASH therapy.

• 한국주조공학회지
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• 제11권3호
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• pp.217-227
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• 1991

The present study was conducted to estimate the fatigue crack growth rate of the Mo-Ni alloyed ductile cast iron for the influence of austempering temperature and time. The fatigue crack growth rate was affected by retained austenite. Retained austenite volume were higher with the ductile cast irons which were austempered at $360^{\circ}C$ than austempered at $260^{\circ}C$, and the fatigue crack growth rate of the former was lower than that of the latter. Also, the fatigue growth rate of the former was the lowest at austempering for 1 hour and that of the latter was the lowest at austempering for 3 hours.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1874-1875
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• 2004

A high rate deposition sputtering process of magnesium oxide thin film in oxide mode has been developed using a 20 kW unipolar pulsed power supply. The powersupply was operated at a maximum constant voltage of 500 V and a constant current of 40 A. The pulse repetition rate and the duty were changed in the ranges of 10 ${\sim}$ 50 kHz and 10 ${\sim}$ 60 %, respectively. The deposition rate increased with increasing incident power to the target. Maximum incident power to the magnesium target was obtained by the control of frequency, duty and current. The deposition rate of a moving state was 9 nm m/min at the average power of 1.5 kW. This technique is proposed to apply high through-put sputtering system for plasma display panel.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.301-303
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• 2014

Flameless combustion, well known as MILD (Moderate Intensity Low oxygen Dilution) combustion or CDC(Colorless Distributed Combustion), is considered as one of the promising technology for achieving low NOx and CO emissions with improving thermal efficiency of combustion system. In this paper, the effects of exhaust gas dilution rate on formation of flameless combustion of liquid fuel were analyzed using three-dimensional numerical simulations for application of gas turbine combustor with high power density. Results show that the local high temperature region was decreased and flame temperature was spatially uniformly distributed due to higher dilution rate of burnt gas as similar pattern of gas phase flameless combustion. But the evaporation and mixing process of liquid fuel are found to be another important factors for formation of flameless combustion.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.37-40
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• 1996

Cable-In-Conduit Conductor(CICC) is widely accepted as an advanced superconductor configuration for large scale applications such as tokamak fusion reactors, MAGLEV (MAGnetic LEVitation), and SMES (Superconducting Magnetic Energy Storage). The stability of CICC cooled with supercritical helium can be very high if it is operated below a certain limiting current. This limiting current can be determined by Stekly type heat balance equation. The stability characteristic of CICC for AC operation is more complicated than that of DC because there are additional instability sources which are associated with local flux change. Ramp-rate limitation is a phenomenon discovered during US-DPC (United States-Demonstration Poloidal Coil) program, which showed apparent quench current degradation associated with high dB/dt. This paper describes recent experimental investigation results on the ramp-rate limitation and discusses current imbalance, induced current, current redistribution due to local quench of the strand in the cable.

• 한국의학물리학회지:의학물리
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• 제1권1호
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• pp.51-60
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• 1990

Dose distributions around Co- 60 moving source in high dose rate remote afterloading unit, Buchler 3K unit, were experimented with X-omat V films and calculations. In our experiments, film dosimetries have achieved to evaluated the axial dose distributions for source oscillations were 0, 3.5, 5.0 and 6.0 cm in periodically, In results, the dose distributions in axial of source movement showed apparently higher than in transverse direction caused by source locations, dwelling time and air gap in the applicator. In the calculations, the dose rate was derived by using the inverse square law, filteration corrections and Meisberger constant for scatter corrections as source movings. In our experiments and calculations, the average dose uncertainties were showed -2.1$\pm$1.9% in fixed sourdce, -2.9$\pm$1.8%, -7.4$\pm$6.1% and -6.7$\pm$4.6% at 3.5 cm, 5.0 cm and 6.0 cm source oscillations, but the calculations have showed very close to experimental dose rate within 4 cm distance from source.

• 한국정밀공학회지
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• 제20권11호
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• pp.158-165
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• 2003

A specific experimental method, the Split Hopkinson pressure bar (SHPB) technique has been widely used to determine the dynamic material properties under the impact compressive loading conditions with strain rate of the order of 10$^3$/s∼l0$^4$/s. In this paper, dynamic deformation behaviors of rubber materials widely used for the isolation of vibration from structure under varying dynamic loading are determined by using plastic SHPB technique. A transition point to scope with the dynamic deformation behavior of rubber-like material is defined in this paper and used to characterize the specifics of the dynamic deformation of rubber materials.

• International Journal of Industrial Entomology and Biomaterials
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• 제4권1호
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• pp.77-81
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• 2002

A new non-cocooning silkworm variety, Hachojam, suitable for autumn rearing season is single cross Fl hybrid between Japanese race Jam 307 and Chinese race Jam 126. Jam 307, Japanese parent of the Hachojam, which is a source for non-cocooning process showed a high GCA (generation combining ability) in naked pupation rate and Jam 126, Chinese parent, showed a high GCA in pupation rate and single pupal weight. In the local adaptability test performed at 8 local areas in autumn of 1999 to 2000, the naked pupation rate and thin cocoon rate of Hachojam were 64.7% and 35.3% , respectively. The pupal weight calculated from 10,000 of the 3rd molted larvae was 24% heavier in Hachcjam than the cocoon-producing, check variety Daesungjam.

• 설비공학논문집
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• 제3권5호
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• pp.386-394
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• 1991

Freezing of saturated porous media contained in a rectangular cavity has been studied experimentally. Water and different diameter glass beads consitituted the liquid and porous media. Solidification front shape, the effects of bead diameter and initial liquid temperature was investigated. When the hot wall temperature was below $4^{\circ}C$, the freezing rate was higher at the top than at the bottom due to the density inversion, but with increasing the hot wall temperature the freezing rate at the top was effected by the liquid temperature and was lower than at the bottom. With increasing the bead diameter, the difference of freezing rate between top and bottom was increased and depends on thermal conductivity. When the liquid temperature was low in the beginning, the freezing rate was high, but with increasing the time almost the same with those of high temperature liquid.

• Journal of the Korean Wood Science and Technology
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• 제22권1호
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• pp.66-71
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• 1994

To increase drying rate and reduce drying degradation, pretreatments such as prefreezing and presteaming have been widely used in wood industries. Presteaming lumbers prior to kiln drying is known positively to improve its permeability, to increase diffusion coefficient and to reduce discoloration, but negatively to increase collapse. Prefreezing lumbers prior to kiln drying is also known to reduce significantly its drying defects and its shrinkages. Thus it is no doubt that the pretreated lumbers shrink diversely from the untreated. In this study the shrinkage behaviors of the pretreated specimens are investigated by drying two tropical hardwoods (Apitong and Taun) in three different dying conditions: high temperature and slow drying rate (drying in a closed cylinder), high temperature and rapid drying rate (drying in an oven) and low temperature and slow drying rate(drying at room temperature). The prefrozen specimens show the least volumetric shrinkages in most drying conditions. The specimens dried in cylinders shrink most among all drying conditions. In general the pretreated specimens reached the 30 % moisture content faster than the untreated by about 30 %.