• 분석과학
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• 제7권4호
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• pp.427-434
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• 1994

GFAAS(graphite furnace atomic absorption spectrophotometer)를 이용하여 혈액 중 납을 분석할 때, 납은 비교적 휘발성 원소인 관계로 바탕선이 높아지므로 희화 온도를 일정 온도 이상으로 높일 수 없었다. 그래서 종래에는 매트릭스 변형제를 사용하여 희화 온도를 $700^{\circ}C$까지 올려서 희화시켜야 바탕선이 안정되었다. 본 연구에서는 광온도 및 전류 제어 장치가 부착된 기기(Shimadzu, AA-6501S)를 사용하여 온도조절을 단시간에 정확히 함으로써 매트릭스 변형제를 사용하지 않고 Triton X-100으로만 희석하여 분석해도 희화 온도 $550^{\circ}C$ 부근에서 바탕선이 안정됨을 알았다. 또한 자동 바탕 보정 장치인 $D_2$ arc형과 SR(self reversal)법을 비교해 본 결과, 같은 농도에서의 흡광도는 $D_2$ arc형이 높았으나 BGC(background correction)값은 SR법이 높음을 알았다.

• 대한전자공학회논문지
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• 제25권2호
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• pp.204-210
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• 1988

The residue number system offers the possibility of high-speed operation and error detection/correction because of the separability of arithmetic operations on each digit. A compact residue arithmetic module named the self-checking pulse-train residue arithmetic circuit is effectively employed as the basic module, and an efficient error detection/correction algorithm in which error detection is performed in each basic module and error correction is performed based on the parallelism of residue arithmetic is also employed. In this case, the error correcting circuit is imposed in series to non-redundant system. This design method has an advantage of compact hardware. Following the proposed method, a 2nd-order recursive fault-tolerant digital filter is practically implemented, and its fault-tolerant ability is proved by noise injection testing.

• 대한방사선기술학회지:방사선기술과학
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• 제45권6호
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• pp.523-529
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• 2022

Gamma spectroscopy analysis is widely used for radioactivity analysis, and various factors are required for radioactivity calculations. Among the factors, K3 for each sample significantly influences the results. The previous methods of correcting the self-absorption effect include a computational simulation method and a method that requires making a CRM(certified reference material) identical to the sample medium. However, the above methods have limitations when used in small institutions because they require specialized program utilization skills or high manufacturing costs and large facilities. The aim of this study is to develop a method that can be easily and rapidly applied to radioactivity analysis. After filling the beaker with water, we placed the radiation source in a uniform position and used the measured value as the benchmark. Next, a correction factor was derived based on the difference in the radiation source count of the benchmark and the identically measured sample. For the radiation source, Eu-152, which emits a broad range of energy within the measurement range of gamma rays, and Cs-134 and Cs-137, which are indicator nuclides in environmental radiation analysis, were used. The sample was selected within the density range of 0.26-2.11 g/cm³, and the correction factor was derived by calculating the count difference of each sample compared to the reference value of water. This study presents a faster and more convenient method than the existing research methods for determining the self-absorption effect correction, which has become increasingly necessary.

• International Journal of Human Ecology
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• 제4권2호
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• pp.77-87
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• 2003

This paper tried to construct statistical and econometric models on the basis of economic theory in order to discuss the issue of statistical efficiency and unbiasedness including the sample selection bias correcting problem. Comparative analytical tool were one stage Tobit of Maximum Likelihood estimation and Heckman's two-step Tobit of Ordinary Least Squares. The results showed that the adequacy of model for the analysis on demand and choice, we believe that there is no big difference in explanatory variables between the first selection model and the second linear probability model. Since the Lambda, the self- selectivity correction factor, in the Type II Tobit is not statistically significant, there is no self-selectivity in the Type II Tobit model, indicating that Type I Tobit model would give us better explanation in the demand for and choice which is less complicated statistical method rather than type II model.

• Journal of Power Electronics
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• 제12권5호
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• pp.699-707
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• 2012

This paper proposes a single-stage half-bridge electronic ballast with a high power factor using only a single coupled inductor. Compared to conventional high power factor electronic ballasts, the proposed ballast is a simpler circuit with a low cost and a high reliability. The proposed ballast is made up of a power-factor-correction (PFC) circuit and a self-oscillating class-D inverter. The PFC and inverter stages of the proposed ballast are simplified by sharing only a single coupled inductor and two common switches. The proposed PFC circuit can achieve a high power factor and low voltage stresses of the switches. A saturable transformer in the self-oscillating class-D inverter determines the switching frequency of the ballast. Experimental results obtained on a 30W fluorescent lamp are discussed.

• Journal of Radiation Protection and Research
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• 제31권1호
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• pp.47-52
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• 2006

$0.3g/cm^3$ 에서 $1.5g/cm^3$까지 다양한 겉보기 밀도를 갖는 감마방출핵종 환경시료의 정확한 방사능 분석을 위해서 자체흡수보정(self-absorption correction)은 중요한 문제이다. 방사선 표준선원을 밀도별로 제작할 필요없이 마리넬리 비커를 감싸는 외부용기를 새롭게 제작하여 실용적이면서 간단한 자체흡수보정방법을 본 논문에서 제시하였다. 밀도 0.8, 1.0, $1.3g/cm^3$ 대해서 새로운 방법을 이용하여 자체흡수보정을 한 효율들과 밀도별로 직접 표준선원용액을 만들어 측정한 효율값이 4 % 이내에서 일치하였다.

• Nuclear Engineering and Technology
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• 제56권6호
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• pp.2317-2323
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• 2024

Medical linear accelerators with an energy of 8 MV or higher are radiated owing to photonuclear reactions and neutron capture reactions. It is necessary to quantitatively evaluate the concentration of radioactive isotopes when replacing or disposing them. HPGe detectors are commonly used to identify isotopes and measure radioactivity. However, because the detection efficiency is generally calibrated using a standard material with a density of 1.0 g/cm³, a self-absorption effect occurs if the density of the measured material is high. In this study, self-absorption correction factors were calculated for tungsten, lead, copper, and SUS-303, which are the main materials of medical linear accelerator head parts, for each gamma-ray energy using MCNP 6.2 code. The self-absorption effect was more pronounced as the energy of the emitted gamma rays decreased and the density of the measured materials increased. These correction factors were applied to the radioactivity measurements of the in-built and portable HPGe detectors. Furthermore, compared to the surface dose rate measured by the survey meter, the accuracy of the measurements of radioactivity improved by an average of 124.31 and 100.53 % for inbuilt and portable HPGe detectors, respectively. The results showed a good agreement, with an average difference of 3.70 and 5.24 %.

• 한국자연치유학회지
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• 제12권1호
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• pp.1-6
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• 2023

배경: 자가 중력 지압 프로그램 참여 후 내반슬이 개선되는 사례가 개별적으로 확인되고 있으나 체계적인 관찰이 진행되지 못한 상태이다. 목적: 자가 중력 지압 프로그램을 실시 후 무릎 내측 각도의 변화를 후향적으로 관찰하여 자가 중력 지압 프로그램이 내반슬 교정에 미치는 효과를 평가하기 위함이다. 방법: 내반슬이 관찰되는 50명을 대상으로, 지압 도구 위에 누워서 75분간 지압 프로그램을 수행한 후 프로그램 실시 전후 무릎 내측 각도의 변화를 비교했다. 결과: 연구대상자들의 무릎 내측의 평균 각도는 지압프로그램 실시 후 좌측 7.29±3.85° (p < .000), 우측 7.08±3.86° (p < .000) 증가하여 연구 대상자의 내반슬이 유의하게 개선되는 것이 확인됐다. 결론: 본 연구의 결과는 자가 중력 지압 프로그램이 내반슬 교정에 활용될 수 있다는 가능성을 제시한다. 본 연구의 결과를 임상적으로 활용하기 위해, 자가 중력 지압 프로그램이 내반슬을 개선하는 효과에 대한 기전 및 임상적 효과를 최적화하는 추후 연구가 요구된다.

• 국제물리치료학회지
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• 제10권2호
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• pp.1810-1817
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• 2019

Background: Effect of cervical and lumbar tractions on the reduction in the angle of curvature and the effect of a correction exercise or a general traction method on balance, muscle strength, pain, and body alignment, however insufficient research has been undertaken on self traction exercises targeting patients with scoliosis. Purpose: To determine the effect of cervical and lumbar tractions on the reduction in the angle of curvature and the effect of a correction exercise or a general traction method on balance, muscle strength, pain, and body alignment. Design: Randomized controlled clinical trial (single blinded) Methods: Twelve adults(20s) with scoliosis were included in this study and performed a traction program that was composed of a 5-min warm-up exercise, a 15-min main exercise, and a 5-min cool-down exercise (25 minutes in total), three times a week for four weeks. The Chiro traction machine was used for the self-traction exercise. Vertebral alignment, muscle strength, and flexibility were compared before and after the intervention using the paired T-test. Results: The scoliosis angle, pelvic torsion, and lumbar extensor were significantly changed by intervention; however, there was no significant difference in flexibility. Conclusion: The results revealed that self-traction exercise activated blood flow through the extension and contraction of muscles, effectively increasing the function of the muscles around the vertebrae.

• 한국직업건강간호학회지
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• 제11권1호
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• pp.5-12
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• 2002

The purpose of this study, as a project for health management at small workplace by Korean association of occupational health nurse, was to evaluate the program for correction of eating habits to prevent digestive disorders of workers. The study cases were twenty nine workers who voluntarily participated in the above program and they were from small(under fifty employees) workplace at Youngdeungpo-gu, Seoul. The study was done between January, 2000 and May, 2000. This program was concerned with daily menu for correction of eating habits and was composed of individual health education and distributing guide books and video. Nurses visited the workplace for the program once a week or two weeks. The result of this program was evaluated by paired t-test of digestive symptoms, eating habits, and self-efficacy before and after the fulfillment of the program. The result could be summarized as below. 1) There were decrease in digestive symptoms and improvement in eating habits and self-efficacy from study cases after fulfillment of the program. 2) The most common digestive symptoms were heartburn, upper abdominal pain, indigestion. The symptom which had been improved through the program were indigestion, heartburn and anorexia in the order. 3) The most improved eating habit was to eat flat foods instead of salty and spicy foods. The most improved self-efficacy was 'I can follow any helpful guides for my health'. The result indicated the program was successful for workers at small workplace. The continual management by nurses' regular visit once a week or two weeks was the most important thing for the successful program.