• Progress in Superconductivity
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• v.3 no.1
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• pp.99-103
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• 2001

We have conducted two runs of interlaboratory comparison on Ag-sheathed Bi-2223 tapes to evaluate the level of measurement techniques for the critical current measurement. Two classes of specimens were prepared for parallel and serial routings and sent to four participating laboratories. The critical currents of specimens were measured at 77 K in zero magnetic field. In the first comparison, we used twenty different Bi-2223 tapes as specimens for comparison and participating laboratories measured the specimens using their own instruments and procedures. As a result, the scattering of data on the first comparison showed -3.0% to +l2.2% for the parallel routing and -0.7% to +l5.1% for the serial routing. Major sources of these variations were attributed to different measurement techniques. Thus, the second comparison of measurement was done on the same specimens under specified measurement conditions, particularly in terms of cooling procedure and sweep rate of the test current. The variations for the second comparison were decreased -3.1% to +3.2% far the parallel routing and -1.8% to +7.7% fur the serial routing.

• Progress in Medical Physics
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• v.33 no.4
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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.

• Journal of Technology Innovation
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• v.31 no.1
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• pp.105-148
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• 2023

This paper provides a new method of measuring the degree of technological progress which contributes to real economic growth based on Schumpeter's Trilogy. Using Microdata of Statistics Korea, the results of measuring and comparing the actual growth contribution of technological progress during the period 2003-2018 by the total factor productivity growth rate(growth accounting method), the R&D investment contribution rate, and the Schumpeterian innovation growth rate, respectively are as follows. First, the measurement of the real growth contribution of technological progress by the growth rate of total factor productivity and the growth rate of Schumpeterian innovation shows contradictory results. Second, when the growth rate of production is in a decreasing trend, the difference between the growth rate of production and the growth rate of total factor productivity increases compared to when it is in an increasing trend. Conversely, when there is an increasing trend, the difference between the growth rate of production and the growth rate of total factor productivity becomes smaller compared to when it is in a decreasing trend.. Third, the technological opportunity that affects the innovation growth rate, i.e., the contribution of R&D incentives to innovative growth is only 3.3%. The reason why this result is different from the existing perception of the contribution of technological progress to growth is that different entities are being measured while measuring the same term of technological progress. Therefore, the growth rate of total factor productivity should be used to measure macroeconomic efficiency, R&D investment should be used to measure the effectiveness of new technology supply, and the Schumpeterian innovation rate should be used to measure the economic impact of technological progress. The policy implications of the research results of this thesis are as follows: ① Transition from a policy of one-sided technology supply to a policy of convergence of technology supply and new technology demand support, ② Mission-oriented R&D policy and R&D policy that links national R&D with private R&D, ③ Reclassification of capital goods reflecting the degree of new knowledge.

• Progress in Superconductivity and Cryogenics
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• v.19 no.2
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• pp.48-52
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• 2017

Discrepancy between a power supply current and an actual "spiral" coil current makes the conventional 4-probe measurement of a critical current ($I_c$) of a no-insulation (NI) high temperature superconductor (HTS) coil inaccurate and time-consuming. This paper presents a fast and accurate approach for $I_c$ measurement of NI HTS coils. With an NI HTS coil energized at a constant ramping rate, a complete analytic expression for the spiral coil current was obtained from a first-order partial differential equation that derived from an equivalent circuit model of the NI coil. From the analytic solution, both spiral coil current and radial leak current can be obtained simultaneously, which enables fast and accurate measurement of the NI coil $I_c$. To verify the proposed approach, an NI double-pancake (DP) coil, wound with GdBCO tapes of $6mm{\times}0.1mm$, was constructed and its $I_c$ was repeatedly measured with various ramping rates in a bath of liquid nitrogen at 77 K. The measured results agreed well with the calculated ones, which validates the proposed approach to measure $I_c$ of an NI HTS coil.

• Progress in Superconductivity and Cryogenics
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• v.7 no.1
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• pp.21-24
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• 2005

The problem of fluctuation-induced digital errors in a rapid single flux quantum (RSFQ) circuit has been very important issue. So in this experiment, we calculated error rate of RSFQ switch in superconductiyity ALU, The RSFQ switch should have a very low error rate in the optimal bias. We prepared two circuits Placed in parallel. One was a 10 Josephson transmission lines (JTLs) connected in series, and the other was the same circuit but with an RSFQ switch placed in the middle of the 10 JTLs. We used a splitter to feed the same input signal to the both circuits. The outputs of the two circuits were compared with an RSFQ XOR to measure the error rate of the RSFQ switch. By using a computerized bit error rate test setup, we measured the bit error rate of 2.18$\times$$10^{12}$ when the bias to the RSFQ switch was 0.398mh that was quite off from the optimum bias of 0.6mA.

• Journal of Oriental Neuropsychiatry
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• v.18 no.1
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• pp.111-122
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• 2007

Objective : Progressive muscle relaxation(PMR) therapy is the way of mind and body self-regulation which makes major muscles tension to be comfortable condition. It was considered to be important to check the level of relaxation in objective validity. Therefore, Heart rate variability(HRV) is the valuable measurement to investigate the effect of progressive muscle relaxation therapy on autonomic nerve system. Method : I studied 38 subjects. The subjects were measured HRV at first. And then, Using a CD player, the subjects listened to recorded PMR program for 15 minutes. After this progress, I rechecked HRV. Results : heart rate item of HRV was significantly decreased. Also, the numerical value of SDNN(standard deviation of all NN intervals) and SDSD(standard deviation of differences between adjacent NN intervals) items of HRV were showed significantly increased in all subjects after PMR. Conclusion : It indicated that PMR is efficient for inspiring resistance of the stress and a sense of stability, and PMR is a valuable method to reduce the mind stress and stiffness of body muscle.

• Progress in Medical Physics
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• v.5 no.1
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• pp.67-74
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• 1994

Dose distribution of point source represents an inverse square law as the distance, Difference of measurement value and calculation value according to moving distance of radiation source show very large error in dose calculation of Brachytherapy. Therefore, in RALS of high dose rate, dose calculation have an important effect in treatment of uterine cervix cancer and recurrent rate. In this paper, authors measured moving distance of radiation source carrying out RALS. And we measured Rectum dose compared with calculationdose.

• Progress in Medical Physics
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• v.6 no.1
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• pp.13-18
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• 1995

Dose distribution of HDR-RALS source represents an inverse square law as the distance. Difference of measurement value and calculation value according of brachytherapy. Therefore, in HDR-RALS dose calibration and calculation have an important effect in treatment of uterine cervical cancer and absorbed dose of interesting points. In intracavitary therapy, particula attention is paid for precise determination of the doses to be applied. In this report, we have discussed that the calibration of a HDR-RALS, differences between calculation dose use of isodose chart and measurement in rectum. Dose rate calibration of radiation sources are obtained from air kerma and Г factor with calibraed ion chamber for cobalt source. and used semiconductor detector for compared with measurement in phantom. Eighteen patients were treated with a HDR-RALS for intrcavitarty irradiation (ICR) using a cobalt-cesium source. Repoductivity of dose measurements were 0.3 -1.1％ in phantom. The means of dose distribution was -6- ＋21％ between calculation of isodose chart and measurement of recyum, and was same mean value upper 6.3％ in measurement value than calculation does.

• Progress in Superconductivity and Cryogenics
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• v.16 no.2
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• pp.64-69
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• 2014

Measuring an exact amount of remaining cryogenic liquid propellant under microgravity condition is one of the important issues of rocket vehicle. A Pressure-Volume-Temperature (PVT) gauging method is attractive due to its minimal additional hardware and simple gauging process. In this paper, PVT gauging method using liquid nitrogen is investigated under microgravity condition with parabolic flight. A 9.2 litre metal cryogenic liquid storage tank containing approximately 30% of liquid nitrogen is pressurized by ambient temperature helium gas. During microgravity condition, the inside of the liquid tank becomes near-isothermal condition within 1 K difference indicated by 6 silicon diode sensors vertically distributed in the middle of the liquid tank. Helium injection with higher mass flow rate after 10 seconds of the waiting time results in successful measurements of helium partial pressure in the tank. Average liquid volume measurement error is within 11% of the whole liquid tank volume and standard deviation of errors is 11.9. As a result, the applicability of PVT gauging method to liquid propellant stored in space is proven with good measurement accuracy.

• Progress in Superconductivity
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• v.3 no.1
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• pp.36-40
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• 2001

We have studied vortex dynamics in$ Bi_2$$Sr_2$$CaCu_2$O$_{8}$single crystals of unirradiated and irradiated samples by using 100 $\times$ $100\mu\textrm{m}^2$Hall sensor. Doses equivalent magnetic fields are 20 G, 100 G and 1 kG. In the magnetization measurement, a second magnetization peak (SMP) was observed in unirradiated, 20 G dose and 100 G dose samples in contrast to 1 kG dose sample. In the unirradiated sample, the SMP was observed in the range of 18 K ~ 35 K and the amplitude of the SMP decreased with increasing temperature. With increase of the irradiation dose, temperature region and sharpness of the SMP were reduced. In the magnetic relaxation measurement, we observed that the normalized relaxation rate S decreased with increasing the irradiation dose. Our results suggest that the vortex dynamics is not greatly affected by low-density columnar defects.s.