• 미생물학회지
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• 제38권1호
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• pp.7-12
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• 2002

Fusarium section Liseola에 속하는 균주들의 rDNA IGS 부위를 중폭하고 여러개의 제한 효소로 처리하였다. 증폭된 IGS 부위의 길이는 F. moniliforme 12 만이 약 2.9 Kb 이고 나머지 균주들은 모두 약 2.6 Kb였다. 제한 효소 EcoRI, HincII, SalI, PstI 등은 ICS 부위를 절단하여 11균주들에서 9 haplotypes을 확인할 수 있었다. 본 연구에서의 Section Liseola에 속하는 균주들에 대한 결과에 앞서 연구되어진 Section Elegans에 속하는 균주들의 결과를 종합하여 dendrogram을 그렸을 때, IGS 부위를 종내에서와 마찬가지로 종간, section 간의 관계를 밝힐 수 있는 가능성을 제시하여 주었다.

• Steel and Composite Structures
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• 제26권1호
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• pp.31-44
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• 2018

This paper reports a novel steel beam-to-column connection suitable for use in the weak axis of I-section column. Monotonic and cyclic loading experimental investigations and numerical analysis of the proposed weak-axis connection were conducted, and the calculation procedure of the beam-column relative rotation angle and plastic rotation angle was developed and described in details. A comparative analysis of mechanical property and steel consumption were employed for the proposed I-section column weak-axis connection and box-section column bending connection. The result showed that no signs of fracturing were observed and the plastic hinge formed reliably in the beam section away from the skin plate under the beam end monotonic loading, and the plastic hinge formed much closer to the skin plate under the beam end cyclic loading. The fracture of welds between diaphragm and skin plate would cause an unstable hysteretic response under the column top horizontal cyclic loading. The proposed weak-axis connection system could not only simplify the design calculation progress when I-section column is adopted in frame structural design but also effectively satisfy the requirements of 'strong joint and weak member', as well as lower steel consumption.

• 한국구조물진단유지관리공학회 논문집
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• 제10권6호
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• pp.143-153
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• 2006

본 연구에서는 지점부 단면형고 확대를 도입한 연속 프리스트레스트 Steel I-Girder의 휨거동 특성을 파악하고자 하였다. 긴장력 도입 후 정적 휨 재하실험을 수행 하여 지점부 단면형고 확대도입 및 강연선의 배치양상, 도입된 긴장력을 실험변수로 하여 그에 따른 내하력 향상정도를 평가하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 봄 학술발표회논문집
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• pp.51-58
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• 2000

Lateral buckling behavior of laminated composite thin-walled I-section beams subjected to bending moment is investigated by applying the nonlinear anisotropic thin-walled beam theory. The constituent laminated thin-walled elements of I-section are assumed to be symmetrically laminated. The bending, twisting, and warping stiffnesses of the cross section are obtained based on the definitions of these stiffnesses In the thin-walled anisotropic beam theory In numerical examples, singly-symmetric I-beams with specially orthotropic, quasi-isotropic, angle-plys and various boundary conditions are considered. To validate the proposed theoretical approach, present analytical solutions are compared with three dimensional finite element solutions.

• 한국직업건강간호학회지
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• 제7권2호
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• pp.130-135
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• 1998

To investigate the working characteristics of the workers by place of duty, a study was carried out among 591 male workers aged 20-55 employed in an automobile industry in Korea. Workers participated to this study were divided into low back pain(LBP) and control group, according to the self-reports by written questionnaires. Work factors and complaint rates of low back pain were compared to the work places. The results were as follows ; 1) The complaint rates of low back pain were 49.2%(292 men) as a whole, 58.6%(34 men) in Production Control Department I, 50.2%(120 men) in Stamping Tool Department, 46.9%(138 men) in Bus Department. 2) Lifting and earring work of individual workers were directly associated with low back pain. Frequency of lifting and carring work is higher in the Final Body Section(Production Dept. I) and Body I Section(Bus Dept.). 3) LBP group were more frequently involved in working in awkward position(Quality Control Section of Stamping Tool Dept.), bending(Body I Section of Bus Dept.) and twisting posture(Sash Section and Body I Section of Bus Dept.). 4 )Workers exposed to vibration during working shows the higher complaint rate of low back pain.

• 대한간호학회지
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• 제20권2호
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• pp.131-141
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• 1990

Recently, the rate of cesarean section in Korea has been increasing. The results of several previous studies in foreign countries on the emotional responses of cesarean section mothers showed that they might experience difficulties in the mother- infant interaction due to fatigue, lack of early mother - infant interaction, disappointments, anger, feelings of loss of control, and other factors. Human behavior is said to be determined by one's self concept, and self concept is influenced by both internal and external environmental factors. A scale to measure the self concept of cesarean section mothers was needed in order to identify those who might have difficulties in the mother- infant interactions in future. The purposes of this study were to develop a measuring scale, and to test its reliability and validity. The process of this study was as follows. A structured interview was done with 50 cesarean section and vaginal delivery mothers to find their state of emotional reaction after giving birth to their babies. Based on the results of the interviews, a 50 items Likert scale was developed. The self concept of 268 cesarean section and vaginal delivery mothers who were hospitalized at six hospital in seoul were measured, during the period between Feb. 1 and April 30. Reviewing the discriminating power of each item by means of crosstabulation, ten items were selected for the final scale. The reliability and validity of this ten item scale were tested by Cronbach's alpha and t-test, using spss pc＋package. The results of this study and recommendation are as follows. 1. The ten selected items were as follows. I feel pains in my breast. (－) I have a good appetite now. (＋) I feel pains in my flank. (－) I feel fine now. (＋) My body seems to have returned to its prepregnant state. (＋) Thinking of the delivery process, I feel sorry. (－) I want to hold my baby in my arms. (＋) I want to keep my own life, even if I became a mother. (－) I want to delegate the care of the baby to my mother / mother in law. (－) I think baby is my alter ego. (＋) 2. The reliability of this scale was tested by Cronbach's alpha, and the coefficient of this scale was .8066. 3. The construct validity of this scale was tested by means of known group methods. The value of self concept for cesarean section mother was significantly lower than for vaginal delivery mothers(t＝-5.51, df＝266, p＝0.007). 4. The criterion validity of this scale was tested indirectly. Though this scale could discriminate the differences in the self concept between cesarean section and vaginal delivery mothers, the five items on the personal self concept scale didn's show any differences between cesarean section and vaginal delivery mothers. Therefore, the study indicates that those who shows lower values in the personal self concept measurement, that is, lower than 12.03 points, could be regaled as “risk mothers” 5. Further studies using this scale to clarify the influencing factors on negative self concept are strongly recommended.

• Steel and Composite Structures
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• 제4권5호
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• pp.367-384
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• 2004

A numerical model based on the finite element technique is adopted to investigate the behavior and strength of thin-walled I-section beam-columns. The model considers both the material and geometric nonlinearities. The model results were first verified against some of the currently available experimental results. A parametric study was then performed using the numerical model and interaction diagrams for the investigated beam-columns have been presented. The effects of the web depth-to-thickness ratio, flange outstand-to-thickness ratio and bending moment-to-normal force ratio on the ultimate strength of thin-walled I-section beam-columns were scrutinized. The interaction equations adopted for beam columns design by the NAS (North American Specifications for the design of cold formed steel structural members) have been critically reviewed. An equation for the buckling coefficient which considers the interaction between local buckling of the flange and the web of a thin-walled I-section beam-column has been proposed.

• Composites Research
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• 제34권5호
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• pp.323-329
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• 2021

본 논문에서는 불균일한 접착 상태를 가지는 복합재 접착 체결 시편에 대하여 모드 I 하중에서의 파괴 특성을 분석하였다. 이를 위하여 Double Cantilever Beam(DCB) 시험을 수행하였으며 모드 I 파괴 인성을 도출하였다. 불균일한 접착 상태를 갖는 시편의 경우 안정한 균열 성장 구간과 불안정한 균열 성장 구간이 나타남을 확인하였다. DCB 시험에서 구한 하중-변위 선도와 시편의 파손 단면을 통해 각 구간의 파괴 특성을 관찰하였다. 시험에서 측정된 균열 길이를 기준으로 세분화된 구간과 각 구간의 모드 I 파괴 인성을 이용하여 유한요소해석을 수행하였다. DCB 시험 결과와 유한요소해석 결과를 통해 불균일한 접착 상태를 가지는 시편의 파괴 거동을 모사할 수 있음을 확인하였다.

• 한국CDE학회논문집
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• 제14권4호
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• pp.234-241
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• 2009

The use of aluminum parts in automobile structuraI applications has increased in an effort to reduce the weight of cars and hence improve fuel economy. But Aluminum bar, I-beam and channels need other processes to vary the cross section in the axial direction. Thus, applications of these parts are limited by high cost. If the cross section of the part is variable by using only extrusion, application of extruded bar, I-beam and channels will increase in the Aluminum industries. In this paper, we propose the variable-shape extrusion process which can control the thickness of Aluminum bar. And we can calculate the speed of center ram by varying the cross section in the extrusion to control the thickness of Aluminum bar.

• Structural Engineering and Mechanics
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• 제10권5호
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• pp.479-489
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• 2000

Based on the stiffness equation of the tapered beam element involving the effects of axial force and shear deformation, numerical investigations are carried out on elastic instability for web-linearly tapered columns with I-section of steel portal frames. Effects of shear deformation on the effective length of the tapered columns with I-section are studied. An efficient approach for determining the effective length of the tapered portal frame columns considering effects of shear deformation is proposed.