• Computers and Concrete
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• 제15권2호
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• pp.199-213
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• 2015

The residual fracture toughness of post-fire normal-strength concrete subjected up to $600^{\circ}C$ is considered by the wedge splitting test. The initial fracture toughness $K_I^{ini}$ and the critical fracture toughness $K_I^{un}$ could be calculated experimentally. Their difference is donated as the cohesive fracture toughness $K_I^c$ which is caused by the distribution of cohesive stress on the fracture process zone. A comparative study on determining the residual fracture toughness associated with three bi-linear functions of the cohesive stress distribution, i.e. Peterson's softening curve, CEB-FIP Model 1990 softening curve and Xu's softening curve, using an analytical method is presented. It shows that different softening curves have no significant influence on the fracture toughness. Meanwhile, comparisons between the experimental and the analytical calculated critical fracture toughness values further prove the validation of the double-K fracture model to the post-fire concrete specimens.

• Steel and Composite Structures
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• 제9권2호
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• pp.89-101
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• 2009

This paper presents a simplified model to study post-buckling behaviours of the axially restrained steel column at elevated temperatures in fire. The contribution of axial deformation to the curvature of column section is included in theoretical equations. The possible unloading at the convex side of the column when buckling occurs is considered in the stress-strain relationship of steel at elevated temperatures. Parameters that affect structural behaviours of the axial restrained column in fire are studied. The axial restraint cause an increase in the axial force before the column buckles; the buckling temperature of restrained columns will be lower than non-restrained steel columns. However, the axial force of a restrained column decreases after the column buckles with the elevation of temperatures, so make use of the post-buckling behaviour can increase the critical temperature of restrained columns. Columns with temperature gradient across the section will produce lower axial force at elevated temperatures.

• Advances in aircraft and spacecraft science
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• 제1권1호
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• pp.27-41
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• 2014

An active flow control technique based on "smart-tabs" is proposed to delay flow separation on a circular cylinder. The actuators are retractable and orientable multilayer piezoelectric tabs which protrude perpendicularly from the model surface. They are mounted along the spanwise direction with constant spacing. The effectiveness of the control was tested in pre-critical and in post-critical regime by evaluating the effects of several control parameters of the tabs like frequency, amplitude, height, angular position and plate incidence with respect to the local flow. Measurements of the mean static pressure distribution around the cylinder were used to estimate the pressure drag coefficient. The maximum drag reduction achieved in the pre-critical regime was of the order of 30%, whereas in the post-critical regime was about 10%, 3% of which due to active forcing. Furthermore, pressure fluctuation measurements were performed and spectral analysis indicated an almost complete suppression of the vortex shedding in active forcing conditions.

• 한국가정과교육학회지
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• 제14권3호
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• pp.1-9
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• 2002

The objectives of this study were to measure the effect of Practical Reasoning Instruction in Home Economics : specifically. its effect on developing of critical thinking as well as to evaluate the degree of the critical thinking process. with reference to its sub-factors and the level. The research subjects were consisted of the experimental group of 119 freshman class female students from the “A” High School and the comparative group of 110 freshman class female student from the “C” High School in the city of Chung-Ju. This research was conducted under the pre-post test control group design. administering the Pre-Post testing to both the experimental and the comparative groups. The experimental group was subjected to Practical Reasoning Instruction in Home Economics : whereas the comparative group was taught under the lecture-Instruction in Home Economics The research findings are as follows: 1. Those who studied Home Economics under the Practical reasoning method scored higher on the critical thinking Process than the comparative group students who were taught Home Economics in the lecture-style approach. 2. The experimental group of students. who studied Home Economics under the Practical reasoning method. scored higher than the comparative group in their ability to perceive assumption and to render Judgment among the five sub-factors of their critical thinking processes.

• Journal of Trauma and Injury
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• 제28권4호
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• pp.241-247
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• 2015

Purpose: To evaluate the influence of how the trauma care system is applied on the management of trauma patients. Methods: We divided the patients into a pre-trauma system group and a post-trauma system group according to the time when we began to apply the trauma care system in our institution. We compared the general characteristics, injury severity score, initial response time to the trauma patients, number of preventable deaths, and clinical outcomes between the two groups. Results: The numbers of patients in the pre-trauma system group and the post-trauma system group were 188 and 257, respectively. No differences in the patient's median ages, trauma scores (ISS, RTS, TRISS) and proportions of severe trauma patients (ISS>15) were observed between the two groups. The number and the proportion of patients who were admitted to our hospital were increased in the post-trauma system group. The time interval from trauma CP activation to emergency surgery or angio-embolization, and the patient's time spent in emergency room were shortened in the post-trauma system group. However, the lengths of the ICU stay and the hospital stay, and the number of in-hospital mortalities were not improved in the post-trauma system group. In severe trauma patients (ISS>15), there were no differences between the two groups in the number and the proportion of admitted patients, and the time interval from trauma CP activation to performing a diagnostic and therapeutic procedure was not shortened in the post-trauma system group. Conclusion: Application of the trauma care system has shortened the time between the initial response and patient management. However, this improvement was not enough to result in better clinical outcomes. More trauma physicians, multidisciplinary cooperation, and a well-organized trauma management process will be needed if the maximum efficacy of the trauma system is to be achieved.

• 대한토목학회논문집
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• 제11권4호
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• pp.17-26
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• 1991

이 논문(論文)은 단순지지(單純支持) 변단면(變斷面) 기둥의 임계하중(臨界荷重) 및 후좌굴(後挫屈) 거동(擧動)에 관한 연구(硏究)이다. 이 논문(論文)에서는 변단면(變斷面)을 갖는 후좌굴(後挫屈) 기둥의 정확탄성곡선(正確彈性曲線)을 지배(支配)하는 미분방정식(微分方程式)을 3차이론(次理論)에 의(依)하여 유도(誘導)하고, 이 미분방정식(微分方程式)을 Runge-Kutta method와 Regula-Falsi method를 이용하여 임계하중(臨界荷重)과 후좌굴(後挫屈) 기둥의 정확탄성곡선(正確彈性曲線)을 산출(算出)하였다. 실제(實際)의 수치해석(數値解析) 예(例)에서는 변화(變化)높이 구형단면(矩形斷面), 변화폭(變化幅) 구형단면(矩形斷面), 정방형단면(正方形斷面)/원형단면(圓形斷面)의 3가지 단면형상(斷面形狀)에 대하여 수치해석(數値解析)하였다. 수치해석(數値解析)의 결과(結果)로, 하중(荷重)-처짐의 평형경로(平衡經路), 후좌굴(後挫屈) 기둥의 정확탄성곡선(正確彈性曲線), 임계하중(臨界荷重)-단면화(斷面化) 사이의 관계(關係)를 그림에 나타내었다. 또한 단면형상계수(斷面形狀係數)가 임계하중(臨界荷重)과 후좌굴(後挫屈) 거동(擧動)에 미치는 영향(影響)을 분석(分析)하였다.

• 기본간호학회지
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• 제19권3호
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• pp.322-333
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• 2012

Purpose: The purpose of this study was to evaluate the effects of a newly developed Introduction to Clinical Nursing (ICN) program on critical thinking skills, communication competence, self-efficacy, and clinical performance self-confidence in nursing students in their third year. Methods: One group pre-test and post-test design was used with three data collection time points (pre-test, post-test1 and post-test2). Participants were 74 third year nursing students approaching their first clinical practicum. The new program included (a) simulated clinical encounters regarding situations of assessing hospitalized patents and caring for patients with oxygenation needs, (b) objective structured clinical examination of skills, (c) lectures, and (e) field trips. Data were analyzed using paired t-tests. Results: After the ICN course, critical thinking skills(significant only between pretest and post-test2), communication competence, and clinical performance self-confidence improved significantly (p<.05). There was no improvement in the self-efficacy total score but there was significant improvement in the subscale, self-regulatory efficacy. Conclusions: The study results indicate that the ICN course may be effective in increasing critical thinking skills, communication competence, and clinical performance self-confidence in nursing students. However, the effect size was very small and modifications of this program should be considered to develop more cost-effective educational programs.

• 한국의료질향상학회지
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• 제9권1호
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• pp.34-51
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• 2002

Background : The purpose for this study is to develop a critical pathway of bullectomy for spontaneous pneumothorax patients. Methods : For this study a conceptual framework of critical pathway was developed through a review of the literature including five critical pathways which are currently being used in USA, and opinions of the critical pathway development team members at Y university hospital. In order to identify the service contents required by these patients and to draw up a preliminary critical pathway, 33 cases of medical records of patients who had received bullectomy for spontaneous pneumothorax between September, 2000 to August, 2001 at the Respiratory Center of Y university hospital in Seoul was analyzed. Results : In order to test the clinical validity of the preliminary critical pathway, it was applied to ten patients who had received bullectomy for spontaneous pneumothorax from October, 2001 to December, 2001. The average discharge day was 4.89th post operation day, six patients discharged on the fourth post operation day which was the expected day, one patients discharged one day earlier than the expected day, one patient discharged three days later than the expected day, and one patient discharged six days later than the expected day. There were variances between the critical pathway and the actual practice. The variances came from tests, medications, and treatments. One item that showed variance in clinical applications was complemented, and three items were decided not to be corrected for the final determination of the critical pathway. Conclusion : This critical pathway is applicable to the care of patients with bullectomy for spontaneous pneumothorax, but it needs more clinical applications to grasp varied variances.

• Journal of Chest Surgery
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• 제24권5호
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• pp.463-469
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• 1991

Post-anastomotic leakage and stenoses remain major complications and are still responsible for many mortalities after esophageal reconstructive procedures. If the hand-suture is used, anastomotic leaks developed frequently than stenoses. But post-anastomotic leakages are more critical than post-anastomotic stenoses. If the stapler is used, anastomotic stenoses will develop frequently and not critical than anastomotic leakages. The stapler suture method is easier and quicker than the hand suture method in the esophageal anastomotic procedures. But the disadvantages of the stapler suture method is that there is not reachable site with anastomotic stapler the thoracic inlet region and the cost is expensive. We have treated 44 cases of the surgical complications after esophageal reconstructive procedure with conservative and surgical treatment for 10 years from January, 1980 to December, 1989. The anastomotic site stenoses were 8 cases in the hand-suture methods and 4 cases in the stapler-suture methods. The anastomotic leaks were 8 cases in hand-suture methods and 5 cases in stapler-suture methods. There were one death in the surgical repair of four post-operative anastomotic stenoses and two deaths in the surgical repair of three post-operative anastomotic leakages. Ever though we consider that there is more anastomotic leakage than stenoses after the hand-suture methods in esophageal reconstructive procedures. the cost with long stay in the intensive care unit to treat anastomotic leakage after the hand-suture, would be more expensive than-the cost of the treatment of the anastomotic stenoses after auto-suture.

• 한국환경복원기술학회지
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• 제3권4호
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• pp.1-10
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• 2000

This study aims at the new design system development of landscape architecture structures, as soundproof wall using reinforced soil block. This structures, that is new soundproof wall system, have to be maintained stability on acting critical wind load, which is combined exist soundproof wall system and soundproof wall system using environmental green stone block. To the harmony of this system, the post block, so-called landscape block or cast block, is manufactured. It's possible to stand of the post bearing system combined with post-pile and post block. Through the comparison with a serious code for the acting wind load on the soundproof wall, the reasonable wind load could be calculated. Also, the mechanical stability on the green stone block was checked by the Lab. tests based on the UBC (Uniformed Building Code). Because the critical height of soundproof wall system using green stone generally was restricted, the new system demands to combination of the exist system and the new system. For the stability analysis of them, the utility program, SAP2000, was used. And, a semi-auto program on the design system of the new soundproof wall using green stone was developed, which can be easily use because of the simplification.