• Environmental Analysis Health and Toxicology
• /
• 제6권1_2호
• /
• pp.7-23
• /
• 1991

The present study was undertaken to examine the effect of butylhydroxyanisole (BHA) on the lead poisoning in Wister female rats. All experimental rats except normal group were fed with diets formulated by adding BHA in a range of 0.1% to 3.2% and aqueous solution of 1% lead acetate ad libitum through the experimental period. The results obtained are summarized as follows: 1) Lead sedimentation in kidney tissue was decreased with increasing experimental period and BHA level of lead plus BHA-treated groups in comparison with that of lead-treated control group. 2) The weights of lung, spleen and left/right (L/R) kidney were significantly decreased in comparison with those of lead-treated control group after 2 weeks of experimental period, but no difference was shown with those of normal group. 3) The weights of lung, spleen and L/R kidney were increased in lead-treated control group as compared with normal group after 2 weeks of experimental period, but no difference was shown with increasing experimental period. 4) Water intake was remarkably decreased in lead-treated control group as compared with normal group, but water intake by increasing BHA level of lead plus BHA-treated groups showed no significant difference from that of normal group. 5) These results suggest that BHA is effective for reducing the toxic effect of lead in rats.

• 한국대기환경학회지
• /
• 제19권5호
• /
• pp.469-490
• /
• 2003

Atmospheric concentrations of persistent organic pollutants (POPs) were measured at Gosan, Jeju in November 2001 and spring 2002, each time for two weeks. Primary target pollutants were organochlorine pesticides, coplanar polychlorinated biphenyls (co- PCBs), and dioxin/furans listed in the Stockholm Convention adopted in May 2001. Polycyclic aromatic hydrocarbons (PAHs) were also measured in order to understand the overall characteristics of the POPs distribution as well as PM$_{2.5}$, a potent carrier of POPs. In the latter part of the measurement period of November 2001, almost every pollutant of combustion origin including dioxin/furans went high probably due to influence of emissions in the nearby area. The characteristics of atmospheric environment at Gosan in this period were rather close to urban areas far from those of a background area. A severe dust storm swept for three days at the end of the measurement period of spring 2002. However, changes in pollutant concentrations were relatively small except PM$_{10}$. Nevertheless, increases in particulate PAHs and OCDD (octachlorinated dibenzo-p-dioxins), mostly present in fine particles, were observed. Trends in organochlorine pesticide variations were mixed although possible volatilization of DDT residues from soil was inferred from the measurements of spring 2002.2.2.

• Nuclear Engineering and Technology
• /
• 제49권4호
• /
• pp.825-837
• /
• 2017

Due to the severe impacts of recent earthquakes, the use of seismic isolation is paramount for the safety of nuclear structures. The diversity observed in seismic events demands ongoing research to analyze the devastating attributes involved, and hence to enhance the sustainability of base-isolated nuclear power plants. This study reports the seismic performance of a seismically-isolated nuclear reactor containment building (NRCB) under strong short-period ground motions (SPGMs) and long-period ground motions (LPGMs). The United States Nuclear Regulatory Commission-based design response spectrum for the seismic design of nuclear power plants is stipulated as the reference spectrum for ground motion selection. Within the period range(s) of interest, the spectral matching of selected records with the target spectrum is ensured using the spectral-compatibility approach. NRC-compliant SPGMs and LPGMs from the mega-thrust Tohoku earthquake are used to obtain the structural response of the base-isolated NRCB. To account for the lack of earthquakes in low-to-moderate seismicity zones and the gap in the artificial synthesis of long-period records, wavelet-decomposition based autoregressive moving average modeling for artificial generation of real ground motions is performed. Based on analysis results from real and simulated SPGMs versus LPGMs, the performance of NRCBs is discussed with suggestions for future research and seismic provisions.

• 한국광학회지
• /
• 제22권1호
• /
• pp.1-4
• /
• 2011

본 연구에서는 PR 폴리머 장주기 패턴을 이용하여 표면 식각된 격자 구조 기반 장주기 광섬유 격자 제조 방법을 제안하고 외부 장력 및 비틀림, 그리고 외부 굴절률에 대한 민감도를 측정하였다. 외부 장력을 인가함에 따라 특정파장에서 광결합 계수 변화에 의한 공진파장이 형성되고 투과도가 감소하게 된다. 손실이 생기게 되고 민감도는 $-0.033\;dB/\mu\varepsilon$로 측정되었다. 비틀림과 외부 굴절률에 변화에 대해서도 표면 식각된 격자 구조 기반 장주기 광섬유 격자의 투과 특성이 변하며 민감도는 각각 -1.30 nm m/rad, -31.33 nm/RIU로 측정되었다.

• 한국정밀공학회지
• /
• 제25권8호
• /
• pp.29-36
• /
• 2008

An optical rotary encoder is easy to implement for automation system applications. In particular, the output of the encoder has a digital form pulse, which is also easy to be connected to a popular digital controller. By using an incremental encoder and a counting device, it is easy to measure angular displacement, as the number of the output pulses is proportional to the rotational displacement. This method can only detect the angular placement once a pulse signal comes out of the encoder. The angular displacement detection period is strongly subject to the change of the angular displacement in case of ultimate low velocity range. They have ultimate long detection period or cannot even detect angular displacement at near zero velocity. This paper proposes an algorithm for detecting angular displacement by using a dual encoder system with two encoders of normal resolution. The angular displacement detecting algorithm is able to keep detection period moderately at near zero velocity and even detect constant angular displacement within nominal period. It is useful for motion control applications in case of changing rotational direction at which there occurs zero velocity. In this paper, various experimental results are shown for the angular displacement detection algorithm.

• 한국해안해양공학회지
• /
• 제7권1호
• /
• pp.46-56
• /
• 1995

묵호항내 수면교란 현상을 분석하기 위하여 묵초항의 항외, 항입구 및 항내의 3개 정점에서 2회에 걸쳐 약 10일간 수압식 파고계를 이용하여 현상관측을 실시하였다. 관측자료의 스펙트럼 분석 결과 묵호항의 Helmholtz period는 약 10.0-14.3분, 제2 공진주기는 약 3.3분이 되는 것으로 나타났다. 정점 S3에서 Helmholtz period에서의 평균 증폭비는 약 6.8, 관측기간중의 항내에서의 해수위 변위 진폭은 약 5-10cm로 나타났다. 이러한 묵호항의 Helmholtz period 및 제2 첨단주기는 수치모형(정 등, 1993)으로 계산한 결과와 잘 일치하였다. 또한 수치모형실험을 통하여 묵호항의 제1 및 제3 공진주기로 7.5분과 1.9분을 각각 제시하였다.

• 산업기술연구
• /
• 제21권B호
• /
• pp.241-248
• /
• 2001

Normally at a flood season the operation of the dam depends on a short range weather forecast that makes many difficulties of the management at a dry season. It is needed to study the pattern of the long period rainfall. The concept of PMP(Probable Maximum Precipitation) was used for designing dam. From the concept, this study is applied the concept of monthly probable maximum precipitation for operating dam. It can be possible to let us know the appropriateness of a limiting water level at a rainy season. For the operation of dam at a dry season this study can predict roughly the flood season's pattern of precipitation by month or period, therfore the prediction of precipitation can rise efficient operation of a dam.

• 대한족부족관절학회지
• /
• 제16권4호
• /
• pp.223-228
• /
• 2012

Purpose: To treat hallux valgus in old age patients with chevron metatarsal osteotomy and to see the subsequent clinical and radiological outcomes. Materials and Methods: 23 cases of 18 hallux valgus patients of age 60 years or older who received proximal or distal corrective osteotomy from April 2007 to August 2009 and were followed up for at least 1 year were included in the study. The mean age at operation was 65 years (range, 60~81 years), and the mean follow-up period was 2 years and 6 months (range, 1 year~3 years 6 months). Clinical outcome was assessed with the American Orthopaedic Foot and Ankle Society (AOFAS) score, complications, satisfaction rate, as well as measurements and comparison of pre- and postoperative hallux valgus angles, the 1st~2nd intermetatarsal angle, and the position of hallucal medial sesamoid bone. Results: The AOFAS score was improved from preoperative average of 35.1 (range, 13-47) to average 85.1 at last follow-up (range, 75-100). Patients were satisfied about the operation in 21 cases (91.3%). Preoperative hallux valgus angle was $31.7^{\circ}$ on average (range, $19.1^{\circ}-48.9^{\circ}$), and $4.9^{\circ}$ on average at last follow-up (range, $0.3^{\circ}-21.2^{\circ}$). The 1st~2nd intermetatarsal angle was $14.4^{\circ}$on average (range, $8.7^{\circ}-25.7^{\circ}$) and $3.1^{\circ}$ on average at last follow-up (range, $0.6^{\circ}-7.5^{\circ}$). The hallucal medial sesamoid bone position was improved from preoperative average 3.5 (range, 3-4) to postoperative average 1.0 (range, 0-2). Conclusion: Proximal and distal metatarsal osteotomy treatment yielded good clinical and radiological outcomes in old age hallux valgus patients.

• Journal of Nutrition and Health
• /
• 제22권6호
• /
• pp.507-515
• /
• 1989

Ten healthy wome 2-~25 years participated in a 5-week metabolic study to investigate the daily riboflavin requirement of Korean women. Three daily menu and meal patterns were used. Low riboflavin(LR) diet provided riboflavin at a level of 0.71mg / 1000Kcal based on food composition table. High riboflavin(HR) diet provided 1.14mg / 1000Kcal. The riboflavin status was assessed by erythrocyte glutathione reductase activity coefficient(EGRAC) and urinary exretion of riboflavin. Mean EGRAC of LR period and HR period were 1.17+0.08 and 1.01+0.03, repectively. There were discrepanices of riboflavin content of experimental diet between chemical analysis and calculation by Korean food composition table. Urinary riboflavin excretion of subjects was acceptable over the whole study period. It appeared that 0.71mg / 1000Kcal is requirement of riboflavin to maintain EGRAC withing normal range. Thus, it is suggested that current recommendation of 0.6mg / 1000Kcal of riboflavin intake may not be adequate as RDA level in Korea.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 춘계학술대회 논문집
• /
• pp.1350-1358
• /
• 2008

Recently the study related to life cycle cost analysis of railway structure consisted of a complex is proceeded covering several range, which is considering the methodology of efficiency and rationalization for maintenance and analysing long-time behavior of the structure of looking at standpoint from asset management and safety. But LCCA(life cycle cost analysis) of railway structure was almost impossible as there were not anything datum for maintenance plan, such as maintenance periods related to each of components(painting and corrosion of steel, and cracking of elements, etc)and maintenance proportion, despite of its 100-year history. According, for collecting data related to railway truss bridge, bridge record cards and testing safety papers, and researching question, etc are surveyed and classified for LCC Analysis. Especially, LCC assessment on the side of assets-maintenance considering about initial cost, maintenance cost, and indirect cost is constructed. Maintenance period and complementary measure rate are very important in maintenance. To decide maintenance period, Baysian updating method is applied.