• 제목/요약/키워드: National averages

검색결과 261건 처리시간 0.029초

열처리 잣나무 정각재의 재색 변화 및 물성 조사 (Investigation of the Color Change and Physical Properties of Heat-treated Pinus koraiensis Square Lumbers)

  • 임호묵;홍승현;강호양
    • Journal of the Korean Wood Science and Technology
    • /
    • 제42권1호
    • /
    • pp.13-19
    • /
    • 2014
  • 국내의 주 생산 수종인 잣나무 $90{\times}90mm$ 각재의 적정한 열처리 조건을 찾기 위해 3가지 열처리 스케줄을 적용하여 재색과 물성에 미치는 영향을 연구하였다. 1차 열처리시 온도는 $170^{\circ}C$$190^{\circ}C$, 시간은 예비가열시간 1시간을 포함하여 9시간과 13시간을 적용하였다. 2차와 3차 열처리는 모든 공시 각재에 동일하게 $190^{\circ}C$-9시간을 적용하였다. 열처리 횟수가 증가할수록 백색도 $L^*$는 직선적으로 감소하였으며 표준편차도 감소하였다. 열처리 횟수가 증가할수록 색차 ${\Delta}E^*$는 직선적으로 증가하였으며, 표준편차가 커지는 경향이 있었다. 알려진 바와 달리 열처리 시편의 평균 종압축강도가 무처리 시편보다 9% 높았다. 항팽윤율과 중량증가율을 측정하여 열처리 시편의 치수안정성이 무처리보다 크게 증가하였음을 보였다.

중학교 과학에서 탐구자료 활용 수업의 효과 (The Effects of Inquiry Instruction Utilizing Materials in Middle School Science)

  • 김상달;김찬기;김희정;주국영
    • 대한지구과학교육학회지
    • /
    • 제1권1호
    • /
    • pp.63-71
    • /
    • 2008
  • The purpose for this study is to check if research activities can make positive effects on inquiry instruction utilizing materials when compared to traditional instruction utilizing the textbook. The effects of the class should be measured both in cognitive domain and in affective domain. The cognitive domain was measured by the change in achievements in learning science, and the affective domain was measured by the change in learning attitudes of science. The assumptions to be verified in this study were as follows. First, achievements in learning science are higher in the learner oriented inquiry instruction utilizing materials than in the learner oriented traditional instruction utilizing the textbook. Second, learning attitudes of science are higher in the learner oriented inquiry instruction utilizing materials than in the learner oriented traditional instruction utilizing the textbook.The results of the research are as follows. In the cognitive domain, achievements in learning science showed significant change(p=.045) measured by verifying the score for the difference among the averages for each sub-scale, in 5% of meaningful probability, and were higher in the inquiry instruction utilizing materials study. In the affective domain, learning attitudes of science showed significant change(p=.019) measured by verifying the score for the difference among the averages for each sub-scale, in 5% of meaningful probability, and were higher in the inquiry instruction utilizing materials study. In learning attitudes of science, 2 items(self-conception of science, attitudes of learning science) out of 3 items(self-conception of science, attitudes of learning science, learning habits of science) showed significant changes (p=.045, p=.001). But the difference(learning-habits of science) was not significant(p=.914).

  • PDF

산업장 근로자들의 BMI 변화와 혈압 변화의 관련성 (Relationship between Change in Body Mass Index and Blood Pressure among Industrial Workers)

  • 윤석한;조영채
    • 한국산학기술학회논문지
    • /
    • 제16권9호
    • /
    • pp.6130-6141
    • /
    • 2015
  • 본 연구는 산업장 근로자들의 건강검진결과를 토대로 BMI 변화에 따른 혈압의 변화 및 고혈압 발생비율과의 관련성을 명확하게 파악하고자 시도하였다. 조사대상은 2002년부터 20012년까지 11년간 정기건강검진을 받았던 30세부터 69세까지의 산업장 근로자 28,249명(남자 25,548명, 여자 2,701명)으로 하였다. 자료의 분석은 2002년부터 20012년까지의 BMI 구분에 따른 혈압의 평균치를 분석하였다. 또한, 기준년도(2002)로부터 10년간의 BMI의 변화량구분별로 혈압의 평균변화량을 산출하였으며, 정상혈압에서의 BMI 구분별 10년간의 고혈압의 년차별 비율을 분석하였다. 연구결과, 10년간의 평균혈압은 BMI가 저체중군에서 정상체중군, 비만군으로 갈수록 유의하게 증가하였으며, 10년간의 고혈압 발생비율도 BMI가 낮은 군에서 높은 군으로 갈수록 유의하게 증가하였다. 결론적으로 10년(2002-20012)간의 BMI의 증가는 혈압의 증가에 유의한 영향을 미치는 것으로 밝혀졌다.

지연 고정 루프 기반의 지터 억제 클록 발생기 (A Jitter Suppressed DLL-Based Clock Generator)

  • 최영식;고기영
    • 한국정보통신학회논문지
    • /
    • 제21권7호
    • /
    • pp.1261-1266
    • /
    • 2017
  • 지연 시간 전압 분산 변환기 (DVVC) 및 평균 회로 (AC)가 있는 지터 억제 지연 고정 루프 (DLL) 기반 클록 발생기를 제안하였다. 제안한 클록 발생기는 지연고정루프에서 무작위로 발생하는 지터와 회로의 구조에 의해 발생하는 지터를 억제하도록 하였다. 지연 시간 전압 분산 변환기는 각 지연단의 지연 차이를 감지하고 출력 전압을 생성한다. 평균회로는 두개의 연속되는 지연 시간 전압 분산 변환기의 출력 전압을 평균화 한다. 지연 시간 전압 분산 변환기 및 평균 회로는 연속적인 지연단의 지연 시간을 평균화하고 모든 지연단의 지연 시간을 동일하게 만든다. 또한 루프필터 출력 전압의 변동을 줄이기 위해 부궤환 기능으로 효과적인 작동을 하는 스위치가 있는 커패시터가 도입되었다. One-poly six-metal $0.18{\mu}m$ CMOS 공정으로 제작 된 DLL 기반 클록 발생기의 측정 결과는 13.4 ps rms 지터특성을 보여준다.

A Study on Morphology and Behavior of the Sapsaree : A Korean native dog (Canis familiaris)

  • Han, Kook-Il;Alam, Mahboob;Lee, Yun-Mi;Lee, Dong-Hoon;Ha, Ji-Hong;Kim, Jong-Joo
    • Journal of Animal Science and Technology
    • /
    • 제52권6호
    • /
    • pp.481-490
    • /
    • 2010
  • This study was conducted to characterize the morphological and behavior patterns of Sapsaree dogs. The population (n=8,256) has been constructed since 1990 over 12 generations and managed at the Sapsaree Breeding Research Institute, Gyeongsan, Gyeongbuk province. Eighteen morphological and seven behavioral traits were investigated for 882 individuals. Linear models were applied for each trait by fitting sex, season of birth, hair color or test age. The averages of body weight, body length, body height, and depth of chest were $20.5{\pm}2.4\;kg$, $57.3{\pm}4.2\;cm$, $52.1{\pm}3.6\;cm$, and $21.1{\pm}2.4\;cm$, respectively. Males had greater estimated values than females for these body conformation traits. The chocolate Sapsarees had greater averages for body weight, body height and chest depth. The older animals (>2 years) had heavier body weight than younger animals. About 54, 69, 97, 39 and 83.3% of the Sapsarees had hairs with yellow color, straight, medium to long, untangled, and longer around eyes, respectively. Also, about 40% brown eye, 43% curly tail, 78% normal jaw, 86% no missing teeth, 90% no dewclaw, and >90% with black nose, pendent ear, tongue without spots were observed. About 95% males were normal in testicles state. The males performed significantly better than the females for majority of the behavioral traits. For nerve stability, affability, wariness, adaptability, sharpness, activity, and reaction during blood drawn about 79%, 73%, 76%, 61%, 70%, 48% and 81% of the Sapsarees performed at desired level. In general, the Sapsarees showed good characteristics for both morphological and behavioral traits, which can be exploited to use the Sapsaree breed as a companion or guide dog.

무작위와 체계적인 것에 의한 지터를 제어하는 지연고정루프 (A Random and Systematic Jitter Suppressed DLL)

  • 안성진;최영식;최혁환
    • 한국정보통신학회:학술대회논문집
    • /
    • 한국정보통신학회 2016년도 춘계학술대회
    • /
    • pp.693-695
    • /
    • 2016
  • 무작위와 체계적인 것에 의한 지터를 제어하는 지연고정 루프가 소개 되었다. AC는 연속적인 지연단의 지연 시간을 평균화 하고 모든 지연 단의 지연시간을 동일하게 한다. 지연위상고정을 기반으로한 0.18um CMOS공정으로 제작된 클럭 발생기의 측정결과는 13.4ps rms 지터 크기를 보였다.

  • PDF

Prediction Models for Racing Performance of Domestic Progeny of Thoroughbreds

  • Lee, Jeong-Ran;Lee, Jin-Woo;Kim, Hee-Bal;Oh, Hee-Seok
    • Journal of Animal Science and Technology
    • /
    • 제52권6호
    • /
    • pp.459-466
    • /
    • 2010
  • In this study, we suggest an objective standard in selection of candidate horse mates. Korea Racing Authority provided racing records and pedigree information of 44 sires and 954 dams. The datasets were used to predict Racing Indices represented by the averages of earnings earned by offspring for each dam and sire that indicate the racing performance of its domestic progeny. Proportion of wins and second places to the number of taken races and the mean of distances for the won races of a sire were significant factors in linear model with minimum prediction errors. For dam, those factors were the average of earned money per race, number of outstanding broodmares in pedigree, and the comparable index which indicates the relative affinity with its mate. We can use the resultant model for a horse mate by choosing one of the candidates with the largest predicted value for hypothetical offspring.

혼성제 직립벽에 작용하는 파력의 불확실성 해석 (Uncertainty Analysis of Wave Forces on Upright Sections of Composite Breakwaters)

  • 이철응
    • 한국해안·해양공학회논문집
    • /
    • 제23권3호
    • /
    • pp.258-264
    • /
    • 2011
  • 혼성제 케이슨에 작용하는 파력의 불확실성을 확률론적으로 해석할 수 있는 MCS 기법을 제시하였다. 수평파력 및 양력에 대한 확률론적 산정모형을 파력 산정에 사용되는 최대파고의 확률적 특성의 함수로 수립하였다. 파력이 극치분포를 따른다는 가정하에 Goda 식으로부터 산정된 수평파력과 양력에 대한 상대파력의 개념으로 파력의 거동특성을 해석하였다. 이중절단형 정규분포를 이용하는 MCS 기법을 이용하여 축척모수와 형상모수의 불확실성을 고려하였다. 최대설계파고의 초과확률에 따라 상대파력의 평균과 분산을 정량적으로 산정하였다. 해석 결과에 의하면 초과확률이 커짐에 따라 수평파력 및 양력에 대한 상대파력의 평균은 일정하게 감소된다. 특히 양력에 대한 상대 파력은 그 평균값이 수평파력의 평균보다 크고 변동계수는 작게 산정되었다. 이는 동일조건의 초과수준에서 양력에 대한 불확실성이 상대적으로 수평파력의 불확실성보다 작다는 것을 의미한다. 따라서 본 연구의 결과는 파력의 불확실성에 대한 통계적 거동특성을 요구하는 신뢰성 설계 등에서 유용하게 이용될 수 있다.

Determine the hazards of radioactive elements and radon gas manufacturing processes in an Egyptian fertilizer factory

  • Soad Saad Fares
    • Nuclear Engineering and Technology
    • /
    • 제56권5호
    • /
    • pp.1781-1795
    • /
    • 2024
  • This study investigated the levels of radioactivity in soil surrounding a phosphate fertilizer factory in Egypt, aiming to assess potential risks to the population exposed to radiation. Concentrations of 238U, 226Ra, 232Th, and 40K were measured in soil samples collected from two subsites: one near the factory (subsite 1) and another further away (subsite 2). Two different systems were used for measuring radioactivity, a high-purity gamma ray spectroscopy system with an HPGe detector for gamma-emitting isotopes and a CR-39 solid nuclear track detector for alpha-emitting radon gas. Subsite 1, located close to the factory, displayed significantly elevated levels of 226Ra compared to global background levels (514 and 456 Bq/kg vs. 35 Bq/kg). Additionally, the concentrations of 238U (241.06 Bq/kg vs. global average 35 Bq/kg), 232Th (16.15 Bq/kg vs. global average 30 Bq/kg), and 40K (146.36 Bq/kg vs. global average 400 Bq/kg) were all above global averages. Furthermore, a high concentration of radon gas (337.06 μSv/y) was measured at subsite 1. The strong positive correlation observed between 226Ra and 238U (0.96256) provides further evidence of potentially elevated radioactivity levels near the factory. In contrast, subsite 2, situated farther from the factory, exhibited natural radioactive background levels within international limits. Quantitative analysis revealed that gamma ray absorbed doses for 226Ra and 232Th exceeded global averages in some samples. Specifically, 226Ra doses ranged from 7.8 to 46.26 ppm (exceeding the 20 ppm global average in some cases), and 232Th doses ranged from 1.98 to 9.14 ppm (exceeding the 10 ppm global average in some cases). The concentration of 40K, however, remained within the global range (0.07%-0.69 %). The observed imbalances in the ratios of Th/U (0.17-0.24 Bq/kg and 0.73-0.24 ppm) and U/Ra (0.81-0.73 Bq/kg and 0.73-0.17 ppm), both of which are significantly lower than their respective global averages of 4 and 2.4, point towards the presence of fertilizer-derived contamination. This conclusion is further supported by the high phosphate concentrations detected in the samples. Overall, this study suggests that radioactive contamination near the phosphate fertilizer factory significantly exceeds global background levels and international limits in some cases. This raises concerns about potential risks posed to surrounding agricultural land and crops.

Oil content and Fatty Acids Composition of 83 Groundnut (Arachis hypogaea L.) Genetic resources

  • Jae Eun Lee;Awraris Derbie Assefa;Young Jee Kim;Ae jin Hwang;Bich Saem Kim
    • 한국자원식물학회:학술대회논문집
    • /
    • 한국자원식물학회 2020년도 춘계학술대회
    • /
    • pp.95-95
    • /
    • 2020
  • The groundnut (Arachis hypogaea L.), also known as peanut, is a high amount of good-quality vegetable oil in seeds cultivated worldwide. The aim of this study was to evaluate and analyze oil composition of 83 groundnut accessions collected from 7 countries include Korea and Philippines. Total oil contents were recovered by Soxhlet extraction and the fatty acid compositions were analyzed by using gas chromatography. Total oil contents of 83 groundnut accessions showed a significant variability among the entire domain of collections and rangerd from 44.59 to 57.58 %. The averages of palmitic and stearic acid were 11.36 and 3.39 % ranged from 8.77 to 13.65 %, and 1.88 to 7.22 %, respectively. Oleic and linoleic acid showed a wide variation which ranged from 40.32 to 61.67 %, and 22.54 to 41.99 %, respectively. Arachidic acid was ranged from 0.93 to 2.42 %. Significant negative correlation was observed between oleic and linoleic acid.

  • PDF