• Steel and Composite Structures
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• 제39권4호
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• pp.401-417
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• 2021

This study experimentally reveals the influence of welding on grade S690Q high strength steel (HSS) butt joints from both micro and macro levels. Total eight butt joints, taking plate thickness and welding heat input as principal factors, were welded by shielded metal arc welding. In micro level, the microstructure transformations of the coarse grain heat affected zone (CGHAZ), the fine grain heat affected zone (FGHAZ) and the tempering zone occurred during welding were observed under light optical microscopy, and the corresponding mechanical performance of those areas were explored by micro-hardness tests. In macro level, standard tensile tests were conducted to investigate the impacts of welding on tensile behaviour of S690Q HSS butt joints. The test results showed that the main microstructure of S690Q HSS before welding was tempered martensite. After welding, the original microstructure was transformed to granular bainite in the CGHAZ, and to ferrite and cementite in the FGHAZ. For the tempering zone, some temper martensite decomposed to ferrite. The performed micro-hardness tests revealed that an obvious "soft layer" occurred in HAZ, and the HAZ size increased as the heat input increased. However, under the same level of heat input, the HAZ size decreased as the plate thickness increased. Subsequent coupon tensile tests found that all joints eventually failed within the HAZ with reduced tensile strength when compared with the base material. Similar to the size of the HAZ, the reduction of tensile strength increased as the welding heat input increased but decreased as the thickness of the plate increased.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 가을 학술발표회 논문집
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• pp.3-44
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• 1999

This paper discusses the lateral behavior of single and group piles in homogeneous and non-homogeneous(two layered) soil. In the single pile, the model tests were conducted to investigate the effects on ratio of lower layer height to embedded pile length, ratio of soil modules of upper layer to lower layer, boundary rendition of pile head and tip, embedded pile length, pile construction condition, ground condition with saturate and moisture state in Nak-Dong river sand. Also, in the group pile, the model tests were to investigate the effects on spacing-to-diameter ratio of pile, pile array, ratio of pile spacing, boundary condition of pile head and tip, eccentric load and ground condition. The maximum bending moment and deflection induced in active piles were found to be highly dependent on the relative density, pile construction condition, boundary condition of pile head and tip. Based on the results obtained, it was found that the decrease of lateral bearing capacity in saturated sand was in the range of 31% - 53% as compared with the case of dry sand. Also, in the group pile, a spacing-to-diameter of 6.0 seems to be large enough to eliminate the group effect for the case of relative density of 61.8%, and 32.8%, and then each pile in such a case behaves essentially the same as a single pile. In this study, the program is developed by using the modified Chang method which used p - y method and the exact solution of governing equation of pile and it can be used to calculate the deflection, bending moment and soil reaction with FDM in non-homogeneous soil. In comparing the modified Chang method with field test results, the predict results shows better agreement with measured results in field tests.

• Composites Research
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• 제15권2호
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• pp.11-17
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• 2002

우수한 동적 감지특서을 갖는 압전필름센서는 구조 건전성 모니터링이나 평가와 같은 구조물과 재료의 변화를 분석하는데 사용될 수 있다. 압전필름센서의 이러한 특성을 이용하여 Gr/Ep 복합재 평판의 충격 손상개시를 모니터링하였다. 압전필름센서와 스트레인게이지를 Gr/Ep 복합재 평판에 부착하여 다양한 조건의 에너지에 대한 충격시험을 낙하식 충격 시험기를 사용하여 수행하였다. 충격시험을 수행하는 동안 영구압입, 기지균열, 층간분리와 같은 충격 손상개시를 예측하기 위하여 센서신호를 분석하였다. 충격에너지를 초기 손상이 발생할 수 있는 크기 이상으로 증가시키면 손상의 개시와 진전에 대한 정보를 포함하는 특정 센서 신호를 관찰할 수 있었다. 특히, 압전필름세서는 스트레인게이지 보다 충격 손상개시 및 진전에 대한 좋은 감지 특성을 보여주었다.

• 한국균학회지
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• 18권2호
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• pp.96-101
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• 1990

양송이 주요병해인 마이코곤병(M. perniciosa)의 생물적방제를 위한 항균성 미생물을 선발하기 위하여 실시한 시험 결과를 요약하면 다음과 같다. 1. 미생물의 분리는 Starch casein, Soybean meal, Oat meal 배지에서 균집락 형성과 균집락의 특성이 다른 배지 보다 빠르며, 다양한 미생물의 분리가 용이하였다. 2. 실내시험에서 사상균 91, 세균 342, 방사선균 556균주의 미생물을 분리 선발한 후 Oat meal 배지에서 대치배양하여 항균력이 높은 세균 12, 방사선균 71균주를 선발하였다. 3.실내에서 항균력이 있는 균주에 대해 실시한 1차 포장시험에서 5개 균주가 수량 및 항균력이 우수하였으며, 확인시험에서는 AJ-117, AJ-136, AK-139의3균주가 뚜렷한 항균력이 있었다.

• 한국학교보건학회지
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• 제11권1호
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• pp.75-90
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• 1998

The purpose of this study is to identify the stressful events, students their coping methods, and to provide data which maintain and promote healthy students, mentally and physically, The data were collected from total of 481 students from a technical high school in Pusan The Questionnair survey was done from February 2 to February 14, 1988 Analysis of the data was done using descriptive statistics, frequency, ANOVA and a t-test, The findings of the research were as follows: 1) As to the general characteristics of the 481 subjects, 376 (78.2%) were boys and 105 (218%) were girls In terms of health, 93% were in poor health From the results, It seems that when students have problems, many of them seek advice from their friends while nobody seeks advice from their teachers. 2) This study found that most students have many stressful events. In boy students, the most serious events were the following, 'death of parents', 'death of brother or Sister', 'divorce of parents' In girl students, the most serious erents were the following: 'death of brother or sister', 'death or serious sickness of friend', 'death of parents'. 3) To cope With these events, boy students used positive ways such as the following, 'to listen to music', 'to bear', 'to think through the problems' To cope with stressful events, girl students used the following positive methods 'to listen to music', 'to talk with others', 'to sing', 'to sleep' and 'to weep', A small percentage of students used the following negative methods 'to drink alcohol', 'to skip school' and 'to escape from home' 4) The relationship between stressful events and general characteristics represented Significant differences in academic scores (F=1.440, p=0008), health state (F=1.388, p=0.015), and relationship with parents (F=1.685, p=0.000) The relationship between general characteristics and coping methods represented a significant difference in sex (t=-3.100, p=0.002).

• 대한간호학회지
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• 제14권2호
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• pp.63-74
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• 1984

This study attempted to analyze and confirm the correlation between self-concept and the degree of satisfaction on clinical practice. The subjects of the survey were 194 junior and senior students selected from S universities by questionaire from Nov. 1 to Nov. 30, 1983 in Seoul. The collected data was analyzed by t-test, AN-OVA, Pearson correlation according to purpose of study. The results were as follows: 1. Self-concept by religion was significant (F = 4.51, df=4/185, p= .002). 2. In the motives of selecting the nursing, most of students chose the nursing depending on their altruism(62.9%), ability and aptitude(57.7%) and better opportunity of studying abroad and Setting a job(49.5％） respectively. 3. The degree of clinical practice satisfaction was low as 2.80 of a total score 4.0. The degree of satisfaction of contents(3.33) revealed to be high. Compared with the degree of satisfaction on instruction(2.77), practice hours(2.83), practice environment (3.65), and clinical evaluation(2.60) revealed to be low. Religion and choice order of the admission were not significant in satisfaction of clinical practice(t=.37, p=.715). The main hypothesis that“The more positive self concept will be, the higher the degree of satisfaction on clinical practice will be”was not supported (r= .0509, p=.240). The first sub-hypothesis that“The more positive the cognitive self-concept will be, the higher the degree of satisfaction will be”was partially supported. Because favorite-isolated self-concept was significantly correlated with the satisfaction (r=.1189, P=.005). The second sub·hypothesis that“The more positive the evaluational self-concept will be, the higher the degree of satisfaction on clinical practice will be”was not supported. As a above results, self-concept was not influenced to the degree of satisfaction on clinical practice, therefore it is required that environment, instruction method and evaluation for clinical practice should be refined and improved by clinical administrators and nursing faculties for nor-sing student's satisfaction on clinical practice.

• 한국수산과학회지
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• 제15권4호
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• pp.317-322
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• 1982

꽁치를 통째로 미끼로 하는 다랑어 주낙으로 어획된 다랑어 위속에 들어있는 꽂치 토막의 어체부체별 빈도에서 다랑어의 섭취 습성을 추측하였다. 꽁치 토막을 머리와 꼬리의 유무에 따라 분류하여 꽁치 온마리(A토막) 머리 토막(B토막) 몸통 토막(C토막) 및 꼬리 토막(D토막)으로 구분하고 다랑어 위를 위속에 들어있는 꽁치 토막에 따라 독립적으로 구분하여 A위 , B 위 및 C, D위로 정하고이 호정별로 3개의 소표본을 얻은 다음 소표본마다 그 유의특성을 제거하기 위하여 위와 동-발인 꽁치 토막의 빈도에서 위와 동수만콤의 빈도를 제외한 나머지 빈도에서 위의 호정과 꽁치 토막의 부위와의 관련성을 $X^2$검정하여 다음의 결론을 얻었다. (1) 꽁치의 머리 토막을 삼키고 어획된 다랑어는 먼저 꼬리 토막을 떼어 삼킨 다음 그 꽁치의 머리토막을 삼킨 것으로 인정되는 것이 많다. (2) 꽁치의 머리 토막을 삼킨 다랑어의 조획률은 꽁치 온마리를 삼킨 다랑어의 조획률보다 높아.(3) 꽁치의 머리(A토막과 B토막)를 삼킨 다랑어가 낚시에 낚이지 아니한 것은 아마 꽁치의 꼬리부를 먼저 물어서 그 미끼의 머리가 낚시에서 연도된 것을 삼켰을 것이다.

• 한국통신학회논문지
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• 제34권3C호
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• pp.297-303
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• 2009

집적 영상 기술은 잘 알려진 3D 영상 기록 및 디스플레이 기술이다. 집적 영상에서 사용되는 대용량 데이터는 3D 영상을 저장하고 전송하기 위한 압축 기법을 요구한다. 기존의 압축 방법에서는 동일한 기록 시스템을 사용한 다할 지라도 요소 영상의 데이터 크기가 3D 물체의 위치, 조명과 렌즈 배열 등의 다양한 기록 조건에 따라 크게 달라진다. 본 논문에서는 기록 조건에 따른 요소 영상 특성의 의존성을 줄이기 위하여 집적 영상에서 요소 영상의 분할 영역을 이용한 압축 기법이 제안된다. 제안된 기법은 각 3D 물체의 픽업 위치에 따른 요소 영상의 지역적 유사성을 고려하여 향상된 압축률을 보여준다. 제안된 기법의 효율성을 보이기 위하여, 다양한 요소 영상들이 픽업되었고 표준 MPEG-4를 이용하여 압축이 진행되었다. 실험을 통하여 제안된 압축 기법이 기존의 압축 방식에 비하여 9%의 압축률 향상을 보였다.

• Journal of Microbiology
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• 제45권5호
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• pp.453-459
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• 2007

We developed a multiplex PCR (mPCR) assay to simultaneously detect Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Ureaplasma urealyticum, Corynebacterium spp. and seudomona aeruginosa. This method employs a single tube and multiple specific primers which yield 200, 281, 346, 423, 542, and 1,427 bp PCR products, respectively. All the PCR products were easily detected by agarose gel electrophoresis and were sequenced to confirm the specificity of the reactions. To test this method, DNA extracted from urine samples was collected from 96 sexually transmitted disease or prostatitis patients at a local hospital clinical center, and were subjected to the mPCR assay. The resulting amplicons were cloned and sequenced to exactly match the sequences of known pathogenic isolates. N. gonorrhoeae and Corynebacterium spp. were the most frequently observed pathogens found in the STDs and prostatitis patients, respectively. Unexpectedly, P. aeruginosa was also detected in some of the STD and prostatitis samples. More than one pathogen species was found in 10% and 80.7% of STD and prostatitis samples, respectively, indicating that STD and prostatitis patients may have other undiagnosed and associates. The sensitivity of the assay was determined by sing purified DNA from six pathogenic laboratory strains and revealed that this technique could detect pathogenic DNA at concentrations ranging from 0.018 to $1.899\;pg/{\mu}l$. Moreover, the specificities of this assay were found to be highly efficient. Thus, this mPCR assay may be useful for the rapid diagnosis of causative infectious STDs and prostatitis. useful for the infectious STDs and prostatitis.

• 생명과학회지
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• 제13권2호
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• pp.137-142
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• 2003

현재 수박접목묘로서 가장 많이 이용되고 있는 박 종자의 발아율을 높이기 위하여 Priming, $GA_3$, 저온의 단일처리 효과와 저온처리 전후에 가하여지는 priming과 $GA_3$ 의 복합처리 효과를 조사하였던 바 그 결과를 요약하면 다음 과 같다. $3^{\circ}C$에서 1주간 행하여지는 저온처리, 100 mM $KNO_3$에 1일간 행한 priming, 0.01 mM에 1일간 행한 $GA_3$의 단일처리에 대한 발아율을 조사한 결과 저온처리에서 가장 높게 나타났다. 그러나 발아율은 저온처리 후의 priming 처리는 무처리보다는 낮았고 처리기간이 길어질수록 발아율이 현저히 감소되었다. 저온처리 전에 행한 priming과 $GA_3$ 처리는 저온처리 전의 $GA_3$ 처리에서와 같이 농도와 처리기간에 따른 차이가 없었다. 따라서 박의 종자 발아율 향상을 위한 종자처리로써 여러 개의 단일처리를 조합한 복합처리는 처리조합과 순서에 따라 발아율이 영향을 받는 것으로 사료된다.