• 한국공작기계학회논문집
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• 제16권5호
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• pp.7-13
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• 2007

This study proposes a new screw measurement system that is capable of measuring the pitch or lead of a screw, which is one of the most important parameters representing the screw quality. There are various conventional methods for screw measurement including some mechanical and optical ones, but they can not be applied to measure the lead except the profiles or sizes. The newly suggested method is able to measure the pitch or lead directly. This is executed by scanning the thread with a digital probe while the target screw rotates. The devised measurement system is a integrated computer system which is composed of a stepping motor, a digital linear gauge and a chuck device for holding the measured screw. In order to operate the system effectively and conveniently, a computer program having graphical user interface facility is developed. Some experiments were done to prove the effectiveness of the system.

• Safety and Health at Work
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• 제2권2호
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• pp.87-96
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• 2011

In 1967, the problem of occupational lead exposure came to public attention in Korea. Since then, regular progress has been made in lowering workplace lead exposures, instituting new workplace controls, and implementing health examinations of exposed workers. Past serious lead poisoning episodes made it possible to introduce biological monitoring programs on a voluntary basis in high-lead-exposure facilities in Korea. Industry-specific occupational health services for lead workers in Korea during the last 22 years can be categorized into three phases. During the first phase (1988-1993), efforts were directed at increasing awareness among workers about the hazards of lead exposure, biological monitoring of blood zinc protoporphyrin began, and a respiratory protection program was introduced. During the second phase (1994-1997), a computerized health management system for lead workers was developed, blood-lead measurement was added to biologic monitoring, and engineering controls were introduced in the workplace to lower air-lead levels to comply with air-lead regulations. Finally, during the third phase (1998-present), a new biomarker, bone-lead measurement by X-ray fluorescence, was introduced. Bone-lead measurement proved to be useful for assessing body burden and to demonstrate past lead exposure in retired workers. Occupational health service practice for lead workers, including the industry-specific group occupational health system, has brought considerable success in the prevention of lead poisoning and in reducing the lead burden in Korean lead workers during the last several decades. The successful achievement of prevention of lead poisoning in Korea was a result of the combined efforts of lead workers, employers, relevant government agencies, and academic institutes.

• 한국산업보건학회지
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• 제5권1호
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• pp.8-15
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• 1995

사람의 독성 영향을 평가하는데는 생체 시료중 금속의 분석이 중요한 역할을 한다. 우리 나라는 최근에 산업보건 분야에서 이 문제의 필요성이 제기되어 법적인 정도관리 제도를 도입하였다. 연은 특수건강 진단과 산업위생 정도관리 프로그램에서 표준적인 금속으로 이용된다. 과거 20 여년 동안 연중독은 중금속 중독증 발생율이 가장 높았으며 따라서 산업보건 전문기관들은 혈중연 분석의 능력은 필수적인 것으로 되어 왔다. 또한 혈중연은 연 폭로를 평가하는데 가장 중요한 지표이므로 신뢰성과 정확한 분석이 항상 요구된다. 따라서 본 연구는 우리 나라에서 비교적 잘 알려진 산업보건기관에서 혈중연 분석의 실험실간 측정치의 변동을 평가하기 위하여 축전지 제조공장의 68명 연폭로 근로자로부터 2 ml씩 2개의 시료를 채취하여 그 하나는 순천향대 산업의학연구소(SIIM)에서 분석하고 40개의 시료는 C 대학 산업의학연구소(CIIM), 그리고 나머지 28개의 시료는 일본 K 노동위생기술쎈타(JOHC)에서 분석하여 비교하였으며, 한편 일본 전국노동위생연합회(JFOHO)에서 정도관리용 우혈을 농도별로 6종을 구입하여 우리나라 정도관리 프로그램에 참여하고 있는 C 대학 산업의학연구소, 일본 K 노동위생기술쎈타, Y 대학 산업의학연구소, S 대 환경보건과, D 연구소등 6개 기관에서 분석한 결과를 비교하여 다음과 같은 결과를 얻었다. 1. 순천향대 산업의학연구소와 국내 C 대학 산업의학연구소간 혈중연 농도별 분석결과는 평균값에서 유의한 차이가 없었으며 상대표준편차도 3% 미만인 것으로 나타났으며, 일본 K 노동위생기술쎈타와는 평균값에서 역시 유의한 차가 없었으며 상대표준편차는 최고 6.84% 였다. 2. 순천향대 산업의학연구소와 국내 C 대학 산업 의학연구소간 혈중연 농도별 분석결과가 15% 이하의 차이를 나타낸 시료의 수는 40개중 35개로 87.5%의 일치율을 나타내었으며, 일본 K 노동위생기술쎈타와는 28개 시료중 22개로 78.6%의 일치율을 나타내었다. 3. 순천향대 산업의학연구소의 결과를 종속변수로 그리고 국내 C 대학 산업의학연구소간의 분석치를 독립변수로 하였을 때 단순회귀식은 순천향 = 2.19 + 0.9243 C 대학(p=0.0001), 상관계수는 r = 975(p =0.0001)였으며, 일본 기관과는 순천향 = 1.91 + 0.9794 K 일본(p=0.0001), 상관계수 r = 0.965(p=0.0001)였다. 4. 일본 정도관리시료의 공인 값과 본 연구에서 이들 시료를 분석한 기관들 간의 분석치에 대한 단순회귀식의 설명력(R2)은 모두 0.99 이상이었으며 일본 정도관리 시료의 공인 값을 종속변수로 하고 국내 및 일본 기관들의 정도관리 시료 분석치를 독립변수로 하였을 때 기울기는 0.972에서 1.153으로 정체적으로 양호한 일치율을 나타내었다.

• Journal of Preventive Medicine and Public Health
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• 제16권1호
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• pp.19-24
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• 1983

In order to study the effects of iron and zinc on the lead poisoning of rats, lead with iron and zinc, or lead alone were administered orally to a total of 98 adult rats of Sprague-Dawley Species. The concentrations of lead, zinc, and iron were measured by atomic absorption spectrophotometer at every 20 days intervals of 20th, 40th, 60th, 80th and 120th day as a final measurement. Those datas were analysed and compared with those of control groups. The results were summarized as follows; 1. The concentration of lead in blood, bone. and liver tissues kept increasing in case of lead exposure group whereas it started decreasing at 60-80th day when concentration of zinc started increasing in case of combined exposure group. However, in kidney tissue, the concentration of lead in combined exposure group kept increasing up to the end of observation showing special high concentration at the final measurement at 120th day. 2. Concentration of zinc in blood and liver tissues had increased from 60-80th day in case of combined exposure group. 3. Concentration of iron in blood showed decreasing from $44.15{\pm}9.67\;to\;32.44{\pm}2.69{\mu}g/ml$ in case of lead exposure group, whereas it showed constant level of $47.50{\sim}45.65{\mu}g/ml$. However, in liver tissue it kept constant as control did from 40th to 60th days, but from 100th day on it started increasing to show much higher concentration than control.

• 한국산업보건학회지
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• 제33권1호
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• pp.19-33
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• 2023

Objectives: The purpose of this study is to systematically identify situations where exposure levels are expected to be high by structuring domestic lead measurement data according to exposure processes and activities. Methods: Occupational exposure data on lead was collected from the results of the Evaluation of Reliability of Working Environment Measurement conducted by the government from 2019 to 2020. Lead exposure characteristics were analyzed by PROC (process category) and activity. The Risk Characterization Ratios (RCRs) of five PROCs according to ventilation type and lead content were evaluated using the MEASE (Metal's EASE) model. Results: The exposure data on lead (n=250) was classified into 12 PROCs and 12 activities, with an average concentration of 0.040 mg/m³ and about 14% exceeding the occupational exposure limit of 0.05 mg/m³. Processes with high exposure levels were PROC 7 (industrial spraying), 23 (open processing and transfer operations of molten metal), 24 (mechanical treatment), 25 (welding), and 26 (handling of powder containing lead). The results of evaluating RCR for the five PROCs were greater than 1 or close to 1 even if local exhaust ventilation was used. Conclusions: There is a possibility that the concentration of exposure is high in the casting and tapping of molten metal containing lead, mechanical treatment such as fracturing and abrasion, handling of powder, spraying, battery manufacturing, and waste battery recycling processes. It is necessary to implement chemical management policies for workplaces with such processes.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3709-3715
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• 2023

It is an important work to measure the dimensions of underwater spent fuel assemblies in the nuclear power industry during the overhaul, to judging whether the spent fuel assemblies can continue to be used. In this paper, a three dimensional reconstruction method for underwater spent fuel assemblies of nuclear reactor based on linear structured light is proposed, and the topography and size measurement was carried out based on the reconstructed 3D model. Multiple linear structured light sensors are used to obtain contour size data, and the shape data of the whole spent fuel assembly can be collected by one-dimensional scanning motion. In this paper, we also presented a corrected model to correct the measurement error introduced by lead-glass and water is corrected. Then, we set up an underwater measurement system for spent fuel assembly based on this method. Finally, an underwater measurement experiment is carried out to verify the 3D reconstruction ability and measurement ability of the system, and the measurement error is less than ±0.05 mm.

• Journal of Preventive Medicine and Public Health
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• 제30권4호
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• pp.741-751
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• 1997

Measurement of blood lead (PbB) and blood zinc protoporphyrin (ZPP) are most common biological indices to identify the individual at risk for excess or the health sequences by lead exposure. Because PbB is known most important and reliable index of lead exposure, PbB is often regarded as a gold standard to detect lead exposure. But in Korea PbB is a secondary test item of detailed health check-up with positive finding of screening test in most occasion. Our lead standard requires all lead workers to take annual heath-check twice a year for investigation of their health effect due to lead exposure. Blood ZPP is one of most important index to detect high lead absorption in lead workers as a screening test. Measurement of blood ZPP is known ,well to correlate with PbB in steady state of exposure in most lead workers and is often used as a primary screening test to detect high lead absorption of lead workers with the advantage of simplicity, easiness, portability and low cost. The current cut-off criteria of blood ZPP for further detailed health check-up is $100{\mu}g/d\ell$ which is supposed to match the level of $40{\mu}g/d\ell$ of PbB according to our standard. Authors tried to investigate the validity of current criteria of cut-off level $(100{\mu}g/d\ell)$ of blood ZPP and possible another better cut-off level of it to detect the lead workers whose PbB level over $40{\mu}g/d\ell$. The subjects in our study were 212 male workers in three small scale storage battery industries. Blood ZPP, PbB and hemoglobin (Hb) were selected as the indices of lead exposure. The results were as follows. 1. The mean of blood ZPP, PbB and Hb in lead workers were $79.5{\pm}46.7{\mu}g/d\ell,\;38.7{\pm}15.1{\mu}g/d\ell,\;and\;14.8{\pm}1.2g/d\ell$, respectively. There were significant differences in blood ZPP, PbB and Hb by industry (P<0.01). 2. The percents of lead workers whose blood ZPP were above $100{\mu}g/d\ell$ in the group of work duration below 1, 1-4, 5-9 and above 10 years were 8.6%, 17.2%, 47.6%, and 50.0%, respectively. The percents of lead workers whose PbB were above $40{\mu}g/d\ell$ in those were 31.4%, 40.4%, 71.4%, and 86.4%, respectively. 3. The percents of lead workers whose PbB were below $40{\mu}g/d\ell$, $40-59{\mu}g/d\ell$ and above $60{\mu}g/d\ell$ were 54.7%, 34.9% and 10.4%, respectively. Those of lead workers whose blood ZPP were below $100{\mu}g/d\ell$, $100-149{\mu}g/d\ell$ and above $150{\mu}g/d\ell$ were 79.2%, 13.7% and 7.1%, respectively. 4. Simple linear regression of PbB on blood ZPP was statistically significant (P<0.01) and as PbB was $40{\mu}g/d\ell$, blood ZPP was $82.1{\mu}g/d\ell$. 5. While the highest sensitivity and specificity of blood ZPP test to detect lead workers with PbB eve. $40{\mu}g/d\ell$ were observed in the cut-off level of $50{\mu}g/d\ell$ and $100{\mu}g/d\ell$ of blood ZPP, respectively, the highest validity (sensitivity+specificity) of blood ZPP to detect lead workers with PbB over $40{\mu}g/d\ell$ was observed in the cut-off level of around $70{\mu}g/d\ell$ of blood ZPP. But even with optimal cut-off level of around $70{\mu}g/d\ell$ of blood ZPP, still 25.0% of false negative and 20.7% false positive lead workers were found. As the result of this study, it was suggested that reconsideration of current blood ZPP cut-off of our lead standard from $100{\mu}g/d\ell$ to somewhat lower level such as around $70{\mu}g/d\ell$ and the inclusion of PbB measurement as a primary screening test for lead workers was highly recommended for the effective prevention of lead workers.

• 대한전기학회논문지:시스템및제어부문D
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• 제55권7호
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• pp.335-343
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• 2006

We have designed the system that measure one channel ECG by two electrode and extract real-time EDR with more related resipiration and comportable to subject by using conductive textile. On the assumption that relation between RL electrode and potential measurement electrode is coupled with RC connected model, we designed RL drive output to feedback two electrode for reduction of common mode signal. The conductive textile which was used for two ECG electrode was offered more comfort during night sleep in bed than any other method using attachments. In the method of single-lead EDR, R wave point or QRS interval area could be used for EDR estimation in traditional method, it is, so to speak, the amplitude modulation(AM) method for EDR. Alternatively, R-R interval could be used for frequency modulation(FM) method based on Respiratory Sinus Arrhythmia(RSA). For evaluation of performance on AM EDR and FM EDR from 14 subject, ECG lead III was measured. Each EDR was compared with both temperature around nose(direct measurement of respiration) and respiration signal from thoracic belt(indirect measurement of respiration) on mean squared error(MSE), cross correlation(Xcorr), and Coherence. The upsampling interpolation technique of multirate signal processing is applied to interpolating data instead of cubic spline interpolation. As a result, we showed the real-time EDR extraction processing to be implemented at micro-controller.

• Mass Spectrometry Letters
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• 제4권4호
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• pp.87-90
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• 2013

Isotope amount ratios of lead in a bronze sample have been successfully determined using multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). Matrix separation conditions were tested and optimized using ion exchange chromatography with anion-exchange resin, AG1-X8, and sequential elution of the 0.5 M HBr and 7 M $HNO_3$ to separate lead from very high contents of copper and tin in bronze matrix. Mercury was also removed efficiently in the optimized separation condition. The instrumental isotope fractionation of lead in the MC-ICP-MS measurement was corrected by the external standard sample bracketing method using an external standard, NIST SRM 981 lead common isotope ratio standard followed by correction of procedure blank to obtain reliable isotope ratios of lead. The isotope ratios, $^{206}Pb/^{204}Pb$, $^{207}Pb/^{204}Pb$, $^{208}Pb/^{204}Pb$, and $^{208}Pb/^{206}Pb$, of lead were determined as $18.0802{\pm}0.0114$, $15.5799{\pm}0.0099$, $38.0853{\pm}0.0241$, and $2.1065{\pm}0.0004$, respectively, and the determined isotope ratios showed good agreement with the reference values of an international comparison for the same sample within the stated uncertainties

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 춘계학술대회
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• pp.574-576
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• 2010

본 논문에서는 CCD 카메라를 이용해 리드프레임의 내부 리드부의 넓이와 선명도 및 결함 등을 고속으로 검사하는 시스템을 개발한다. 본 시스템은 조명부, 검사부, 조명 제어부, GUI 등으로 구성된다. 개발 기술로는 조명 제어, 고속 검사 알고리즘, 검사 분해능을 올리기 위한 계측기술 등이다. 현장 실험을 통해 개발된 시스템의 유효성을 검증한다.