• Journal of Environmental Science International
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• v.7 no.2
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• pp.203-208
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• 1998

A simple on-line measurement system consisting of a conventional peristaltic pump, a HPLC-type heater, and a flow-through spectrophotometer is introduced for the determination of chemical oxygen demand(CODI. The system was configured such that the reaction mixture in the highly concentrated surffuric acrid medium flowing through the PTFE reaction tubing was heated at 150℃ and the absorbance of dichromate was continuously moutored at 445 m. The same addation principle as in the standard procedure was employed akcept the use of CoSO4 as a new effective catalyst. To test the system, potassium hydrogen phthalate was selected as a COD standard material. With suitably optimized reaction condition, the applicable concentration range depends on the concentration of potassium dichromate in the oxidizing reagent. With 2.0×10-3 M and 5.0×10-4M dichromate, the linear dynamic range was observed up to 400 ppm and 100 ppm, respectively. The standards in the Unear ranges were shown to be completely oxidized, which was confirmed with sodium oxalate or Mohr's salt. In all cases, the typical reproduclbility for betweenruns was 2% or less. The proposed measurement system provides the valuable in- formation for the further development of automated analysis system based on the present standard procedure.

• Journal of Korean Foot and Ankle Society
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• v.5 no.1
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• pp.23-27
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• 2001

It has been known that the ankle arthrodesis is a common surgical procedure for treating the ankle arthrosis and deformity that do not respond to the non-operative treatment. To date, various surgical techniques for the ankle arthrodesis have been reported. Clinical and biomechanical trials have shown that the rigid internal fixation leads the increased rate of the union. The ankle arthrodesis may be complicated with the nonunion, delayed union, malunion, and infection. In cases of the Charcot joint of the ankle in diabetic patients, however, arthrodesis could reduce the disadvantage of the nonoperative treatment, such as the loss of the reduction, progressive collapse, multiple ulcerations and infection. The object of this case report is to report our experience of a successful ankle arthrodesis using an anterior T plate in treating the unstable ankle of a diabetic patient, associated with the ankle fracture and the neuropathy. The surgical approach of this technique is simple so that it would allow less soft tissue injury, and this procedure would be regarded as one alternative to provide the rigid internal fixation in the ankle arthrodesis.

• The Korean Journal of Cytopathology
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• v.4 no.1
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• pp.9-15
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• 1993

The aim of the present study is to demonstrate the usefulness of intraoperative fine needle aspiration (FNA) of pancreatic lesions in 30 patients. A conclusive diagnosis was done in 27 patients and the diagnoses of three patients were deferred. No complications followed the procedure. Based on histologic findings of the resected specimens in 20 cases and of cell blocks in 10 cases, the final diagnoses were adenocarcinoma in 19 cases, chronic pancreatitis in nine cases and tuberculosis in two cases. The sensitivity, specificity and diagnostic accuracy were 95%, 100% and 96% resepectively and there were no false positives. The smear of aspirate was stained with toluidine blue and examined by light microscope. The presence of there-dimensional clusters of disoriented cells and the increased nuclear/cytoplasmic ratio with large prominent nucleoli were the most helpful criteria for a diagnosis of malignancy in the pancreas. The intraoperative FNA of pancreatic lesions was considered as a simple, safe, and highly specific and sensitive tool in differentiating benign from malignant lesions. The intraoperative FNA can be recommended as the first tool of choice of intraoperative diagnostic procedure in lesions of the pancreas.

• Journal of Chest Surgery
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• v.22 no.5
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• pp.753-759
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• 1989

Recently, the arterial switch operation has received more interest and increased application for many patients with TGA [Transposition of the Great Arteries]. Not all patients, however, are suitable candidates for this approach, and its success will be measured against the Senning procedure. From June 1982 through June 1989, 48 consecutive patients underwent correction of TGA by a modification of the Senning procedure in our hospital. 34 were males and 14 females, with ages ranging from 3 months to 99 months [mean age 14 months]. The patients were divided into two groups, group I [TGA with intact ventricular septum or without significant pulmonary hypertension] and group II [TGA with significant pulmonary hypertension]. The hospital mortality was 9.5 % in group I and 55.6 % in group lI. 31 patients were discharged from the hospital after a Senning operation and have been followed a mean of 31.2 months. There were 5 late deaths, 3 in group I and 2 in group II. All patients were followed up with EKG, echocardiogram, and in several cases, Holter monitor and cardiac catheterization and angiography were also performed. There have been arrhythmias in 7, superior vena caval obstruction in 5, pulmonary venous obstruction in 2 and tricuspid insufficiency and/or right ventricular dysfunction in 16 patients. The Senning operation for Simple TGA can be performed with a low operative mortality and morbidity, but tricuspid insufficiency and/or depressed right ventricular function can be a problem with prolonged follow up.

• The Korean Journal of Nuclear Medicine
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• v.21 no.2
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• pp.207-211
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• 1987

A prospecitive study was performed to evaluate the efficacy of Radionuclide Hysterosalpingography (RNHSG), that was modified by McCalley, et al. for the evaluation of fallopian tube. Using spontaneous migration of Tc99m labelled human albumin microsphers (HAM) and images got with Gamma camera, the study was made in 20 gynecological patients (44 tubes) in an effort to confirm the anatomical patency or obstruction as well as functional one at the Department of Obstetrics and Gynecology, National Medical Center from January 1, 1986 to July 31, 1986. The efficacy was also compared with that of contrast hysterosalpingography and surgical observation. Results obtained were as follows; 1) The Radionuclide Hysterosalpingography appeared to be a simple and accurate procedure as a mean with which anatomical tubal patency, as well as functional patency can be detected, although it's some limit in showing anatomical details of uterine cavity and tubes in comparison with contrast hysterosalpingography. 2) The predicted value of tubal obstruction was 82.4%. and that of tubal patency was 88.9% respectively. Overall efficacy (percent of tube correctly classified) of Radionuclide Hysterosalpingography was 88.6%. 3) There was no nuclide related complication during and after the procedure.

• Structural Engineering and Mechanics
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• v.77 no.4
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• pp.463-472
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• 2021

Fully rigid floor diaphragm is one of the main assumptions that are widely used in common practices due to its simple application. However, determining the exact degree of diaphragms flexibility cannot be easily accomplished without finite element modeling, which is an expensive and time-consuming procedure. Therefore, it is always possible that apparently rigid diaphragms, based on prescriptive limitations of seismic codes, experience some degrees of flexibility during the earthquakes. Since diaphragm flexibility has more uncertainties in asymmetric-plan structures, this study focuses on errors resulting from probable floor diaphragm flexibility of torsionally restrained structures. The analytical models used in this study were single-story buildings with asymmetric plan and RC shear walls. Although floor system is not considered explicitly, a wide range of considered diaphragm flexibility, from fully rigid to quite flexible, allows the results to be generalizable to a lot of lateral load resisting systems as well as floor systems. It has been shown that in addition to previously known effects of diaphragm flexibility, presence of orthogonal side elements during design procedure with rigid diaphragm assumption and rapid reduction in their absorbed forces can also be an important source to increase errors due to flexibility. Accordingly, from the obtained results the authors suggest designers to consider the possibility of diaphragm flexibility and its adverse effects, especially in torsionally restrained systems in their common designs.

• Journal of Engineering Education Research
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• v.25 no.2
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• pp.13-21
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• 2022

In many existing studies, the analyses on the application and effect of the project-based learning model (PBL), a student-centered teaching and learning strategy, have been emphasized and carried out in various majors and courses. This case study analyzes the effects of applying a project-based learning model to the engineering accounting course for engineering students in 2021 in the context of the COVID-19 pandemic, compared with the offline course in 2019 and the simple online course in 2020. Project team consisting of 2-3 students carried out online collaborative learning activities for solving open-ended problems through the 5-step PBL procedure including presenting the final result. Except for this online PBL application in 2021, textbooks, lecture contents, assignments, and tests were implemented the same for each semester for three years. Through lecture evaluation and survey by students, the online PBL application semester showed higher effects in inducing student-centered learning, lecture satisfaction, and student competency improvement compared to the non-applying semesters, further, it was evaluated that the online PBL application to the course and evaluation method were more appropriate than other semesters. It is expected that the online PBL method and operation procedure applied in this study can be utilized as a best practice for the design and operation of various online courses for student-centered collaborative learning activities and educational effects.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06a
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• pp.796-801
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• 1994

Measuring noise, sound quality or acoustical comfort presents a difficult task for the acoustic engineer. Sound and noise are ultimately jugded by human beings acting as analysers. Regulations for determining noise levels are based on A-weighted SPL measurement performed with only one microphone. This method of measurement is usually specified when determining whether the ear can be physically damaged. Such a simple measurement procedure is not able to determine annoyance of sound events or sound quality in general. For some years investigations with binaural measurement analysis technique have shown new possibilities for the objective determination of sound quality. By using Artificial Head technology /1/, /2/ in conjunction with psychoacoustic evaluation algorithms - and taking into account binaural signal processing of human hearing, considerable progress regarding the analysis of sounds has been made. Because sound events often arise in a complex way, direct conclusions about components subjectively judged to be annoying with regard to their causes and transmission paths, can be drawn in a limited way only. A new procedure, complementing binaural measurement technology combined with mulit-channel measuements of acceleration sensor signals has been developed. This involves correlating signals influencing sound quality, analyzed by means of human hearing, with signals form different acceleration sensors fixed at different positions of the sound source. Now it is possible to recognize the source and the transmission way of those signals which have an influence on the annoyance of sound.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.12
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• pp.24-29
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• 1997

Recently, Genetic Algorithm(GA), which is a stochastic direct search strategy that mimics the process of genetic evolution, is widely adapted into a search procedure for structural optimization. Contrast to traditional optimal design techniques which use design sensitivity analysis results, GA is very simple in their algorithms and there is no need of continuity of functions(or functionals) any more in GA. So, they can be easily applicable to wide area of design optimization problems. Also, owing to multi-point search procedure, they have higher porbability of convergence to global optimum compared to traditional techniques which take one-point search method. The methods consist of three genetics opera- tions named selection, crossover and mutation. In this study, a method of finding the omtimum size and topology of drilling machine is proposed by using the GA, For rapid converge to optimum, elitist survival model,roulette wheel selection with limited candidates, and multi-point shuffle cross-over method are adapted. And pseudo object function, which is the combined form of object function and penalty function, is used to include constraints into fitness function. GA shows good results of weight reducing effect and convergency in optimal design of drilling machine.

• Journal of Life Science
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• v.15 no.5 s.72
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• pp.755-762
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• 2005

Biochemical amounts of RNA molecules can be synthesized in vitro, which is functionally equivalent or similar to those transcripts normally existing at extremely low levels in vivo. In this study we described a method for efficient preparation of pure T7 RNA polymerase from Escherichia coli strain BL21/pAR1219. The procedure, which used ammonium sulfate fractionation and preparative column chromatography on sephadex SP, was shown to be simple, rapid, and cost effective in comparison with other methods reported previously, Using the purified T7 RNA polymerase we were able to synthesize very long RNA transcript of 1.54 kb length, which is not feasible by conventional chemical synthesis. RNA molecule that was also synthesized by the purified T7 RNA polymerase, such as hammerhead ribozyme, retained its biochemical activity by cleaving the target RNA successfully in vitro. Thus, the procedure shown in this study can be useful to synthesize any length of RNA molecules in vitro in a simple and cost effective way for a variety of purposes.