• Journal of Korean Elementary Science Education
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• v.33 no.3
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• pp.566-578
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• 2014

The purpose of this study is to develop a program for elementary school students' scientific experimental design knowledge generation. This study also investigated the effects of their experimental design ability, as well as the change in the type and elaborateness of their experimental design by applying the program. The subjects of this study was 4 classes in 6th grade of an elementary school located in Seoul, KOREA. The classes were divided into experimental and comparative groups. While the treatment was applied to the experimental group, the comparative group was taught using conventional methods. The pre-test and post-test for students' capability of building scientific experimental design knowledge were conducted to compare the ability of experimental design, the change in the type and elaborateness of experimental design. The findings in this study are as follows: First, the program appeared to be effective in improving experimental design ability. Furthermore, the program appeared to be more effective in generating a higher level of the experimental design type and elaborateness. Therefore, in order to improve experimental design knowledge generation ability, the program can be utilized as effective learning model in elementary school.

• Annals of Laboratory Medicine
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• v.38 no.6
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• pp.619-622
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• 2018

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.66-71
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• 2007

Isochromatics obtained from photoelastic experiment shows the stress distributions of full field of a structure under a load. Therefore stress distributions of the structure can be read at a glace through isochromatics. Many experimental data are obtained from isochromatics. And then, the various photoelastic experimental hybrid methods have been developed. Until now, monochromatic light has been used for photoelastic experimental hybrid method. Therefore the photoelastic experimental hybrid method used until now is called the photoelastic experimental hybrid method for black and white isochromatics. When stresses are analyed by photoelastic experimental hybrid method, many experimental data are needed. Therefore some fringe orders of isochromatics are needed for the photoelastic experimental hybrid method for white and black isochromatics. Therefore in this paper, the photoelastic experimental hybrid method for color isochromatics is developed. In this case, two fringe orders are enough for the experimental data of photoelastic experimental hybrid method for color isochromatics. Applying the method to stress concentration problems, its validity is confirmed. In the precision, the photoelastic experimental hybrid method for color isochromatics is better than the photoelastic experimental hybrid method for white and black isochromatics when fringe orders of isochromatics are few. When fringe orders are few, the photoelastic experimental hybrid method for color isochromatics can be used to analyze stress through few fringe orders of isochromatics.

• Earthquakes and Structures
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• v.18 no.3
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• pp.337-348
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• 2020

Experimental testing has been considered as one of the most straightforward approaches to realize the structural behavior for earthquake engineering studies. Recently, novel and advanced experimental techniques, which combine numerical simulation with experimental testing, have been developed and applied to structural testing practically. However, researchers have to take the risk of damaging specimens or facilities during the process of developing and validating new experimental methods. In view of this, a small-scale structural laboratory has been designed and constructed in order to verify the effectiveness of newly developed experimental technique before it is applied to large-scale testing for safety concerns in this paper. Two orthogonal steel reaction walls and one steel T-slotted reaction floor are designed and analyzed. Accordingly, a large variety of experimental setups can be completed by installing servo-hydraulic actuators and fixtures depending on different research purposes. Meanwhile, a state-of-the-art digital controller and multiple real-time computation machines are allocated. The integration of hardware and software interfaces provides the feasibility and flexibility of developing novel experimental methods that used to be difficult to complete in conventional structural laboratories. A simple experimental demonstration is presented which utilizes part of the hardware and software in the small-scale structural laboratory. Finally, experimental layouts of future potential development and application are addressed and discussed, providing the practitioners with valuable reference for experimental earthquake engineering.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.12 no.1
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• pp.1-13
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• 1990

The main objectives of this study was to observe the effects of hyperbaric oxygen therapy on the healing processes of mandibular fracture of streptozotocin-induced diabetic rats. Author used 60 rats (Sprague-Dawley Strain) deviding into control(30) and experimental groups(30). Complete fracture was produced on the left mandibular body of 60rats, rendered hyperbaric oxygen therapy (2 hrs. daily at 2.5 atm.) on experimental group and observed effects of hyperbaric oxygen therapy by microscopically. The obtained results were as follows; 1. Infiltration of inflammatory cells was no significant differences between the control and experimental group until 3rd week, but experimental group showed decreasing tendency after 4th week. 2. Severe proliferation of fibroblasts showed rather rapider in experimental group, at 2nd week, while at 3rd week in control group. 3. Osteoclasts appeared at 1st week in experimental group while at 3rd week in control group, and experimental group showed early bone resorption pattern. 4. Osteoblasts appeared at 1st week in experimental group while at 3rd week in control group, and experimental group showed prominent osteoblastic activity. 5. Moderate proliferation of capillary blood vessels showed in initial stage of experimental group while mild proliferation at 1-2nd week in control group. 6. Formation of cartilaginous callus showed at 4th week in experimental group, while at 6th week in control group. 7. Formation of bony callus showed mildly at 5th week, and moderately at 6th week in experimental group, while no appearance in control group, but complete bony union was not observed even in experimental group throughout this experiment.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.3
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• pp.217-228
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• 1993

The purpose or this study was to observe the histological alteration of Langerhans cells on wound healing process in applying low energy laser irradiation. For this study, 50 Spraque-Dewly rats, weighing 150Gm or more were devided into control, experimental control group(0), 47.5Hz(1), 190Hz(3), 380Hz(5), 760Hz(7), lased group. All the experimental animals were made excision wound on buccal mucosa, 2mm depth, and lased with stoma laser (904nm, semconductor type ASGaAI, Sedalac France) 47.5Hz, 380Hz, 960Hz, 3minutes one time respectively except experimental control group. After the experiment, experimental animals were sacrificed after 24hours, 48hours, 72hours on each. Taken specimens were embedden in paraffin, sectioned 6-8u in thickness. And the langerhans cell were detected using ant S-100 protein antibody, and histochemically processed with Avidin Biotin complex method. All the Langerhan cells were calculated under light microspe in 400 multiplication field and standard deviation, probability test between each group were evaluated using statistical analysis system(S.A.S)program. Following results were obtained. 1. Langerhan cells were increased in experimental control group compared to that in control group(P<0.01). 2. 24hour after experiments, Langerhans cell were decreased compare to that in control group and control experimental group 5, 1, 3. Probability test shows significance between control experimental and 5, 1, 3 group on a =0.05 range. 3. 48our after experiment, Langerhans cells were decreased compare to that on experimental control group, and probability test shows significance between control experimental and 3, 7, 5 group an a=0.05 range. 4. 72hour after experiments, Langerhans cells were decreased compare to that on experimental control group and probability test on group comparison shows significance between control experimental and 1, 5 and 1 between 3, 7 between 3, and 5, between 7, respeilively on a=0.05 range. 5. Langerhans cells number in experimental group were decreased compare to that on experimental control group in applying laser irradiation.

• Restorative Dentistry and Endodontics
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• v.20 no.1
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• pp.351-361
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• 1995

The purpose of this study was to evaluate the shear bond strength of the composite resin bonded on the bleached enamel surface according to its surface treatment. 90 extracted human premolars were divided into six groups. : enamel unbleached (control group) and enamel bleached with 15% carbamide peroxide for 2 weeks (experimental groups: 1, 2, 3, 4 and 5). The surface of bleached enamel in all experimental groups was treated by following manners. Experimental group 1 : catalase immersion for 3 mimutes. Experimental group 2 : catalase immersion for 15 mimutes. Experimental group 3 : artificial saliva immersion for 1 hour. Experimental group 4 : artificial saliva immersion for 48 hours. Experimental group 5: surface reduction of the bleached enamel about 0.5mm-1mm with superfine diamond bur. Composite resin molds(3mm height, 3mm diameter) were bonded to the untreated enamel and treated. The shear bond strengths of composite resin bonded to enamel of each specimen were tested with universal testing machine at a crosshead speed of 5mm/min and 500Kg in full scale and analyzed statistically. The following results were obtained : 1. Control group had the highest shear bond strength with $19.92{\pm}5.14$ MPa and experimental group 5 had the lowest shear bond strength with $11.15{\pm}4.23$ MPa. 2. Control group showed significant differences in shear bond strength with experimental group 1(P<0.05). 3. Control group showed significant differences in shear bond strength with experimental group 5(P<0.05). 4. Experimental group 4 showed significant differences in shear bond strength with experimental group 5(P<0.05). 5. Experimental group 3 showed no significant differences in shear bond strength with experimental group 4(P<0.05).

• Journal of Periodontal and Implant Science
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• v.24 no.2
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• pp.261-270
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• 1994

The purpose of this study was to evaluate relationship of probing attachment levels, radiographic measurements and surgical measurements according to gingival inflammatory condition. Patients with incipient to moderate periodontitis were selected. Upper and lower premolar and molar teeth excluding third molars were measured. At first visit, gingival index and bleeding on probing were taken, and subjects were grouped into 4 categories as follows : Experimental group I : gingival index 1 and no bleeding on probing. Experimental group II : gingival index 2 and no bleeding on probing absent. Experimental group III : gingival index 1 and bleeding on probing present. Experimental group IV : gingival index 2 and bleeding on probing present. Probing attachment levels were measured with manual probe on mesial and distal surfaces from cementoenamel junctions to terminal ends of probe. Radiographic measurements were made to assess bone loss by measuring the distance from cementoenamel junction to the alveolar crest. After thorough scating, a flap was raised exposing the alveolar bone and surgical measurements were made from cementoenamel junction to alveolar bone. The results were as follows: 1. Differences between probing attachment level and radiographic measurements showed $1.01{\pm}0.73mm$ for experimental group I, $0.98{\pm}0.48mm$ for experimental group II, $0.59{\pm}0.66mm$ for experimental group III, $0.98{\pm}0.38mm$ for experimental group IV and with no significant difference between groups. 2. Differences between probing attachment level and surgical measurements showed $1.36{\pm}0.80mm$ for experimental group I, $1.47{\pm}0.54mm$ for experimental group II, $1.06{\pm}0.39mm$ for experimental group III, $1.41{\pm}0.40mm$ for experimental group IV and with no significant difference between groups. 3. Differences between surgical and radiographic measurements showed $0.36{\pm}0.48mm$ for experimental group I, $0.51{\pm}0.54mm$ for experimental group II, $0.57{\pm}0.72mm$ for experimental group III, $0.41{\pm}0.49mm$ for experimental group IV and with significant difference between experimental group I and experimental group II, III, IV(P<0.05).

• Journal of Periodontal and Implant Science
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• v.35 no.4
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• pp.823-837
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• 2005

The purpose of this study was to study the histopathological correlation between the use of platelet-rich plasma and enamel matrix protein used in conjunction with xenograft. compared to a control group with regards to bone regeneration at the grade III furcation area in beagle dogs. Control group was treated with bovine derived bone $powder(Biocera^{(R)})$, and experimental I group was treated with bovine derived bone powder and Platelet-rich plasma and experimental II group was treated with bovine derived bone powder and Enamel matrix $protein(Emdogain^{(R)})$. The regeneration rate of bone formation was observed and compared histopathologically at 2. 4, and 8 weeks after surgery. The results were as follows: 1. In control group and both experimental groups. inflammatory cells were observed but, new bone formation wasn't. 2. In control group, new cementum on the notch was found in 4 weeks, less mature periodontal ligament when compared to that of experimental group was found and cementum formation was great but, regeneration couldn't be seen in 8 weeks. 3. Experimental I group. new bone formation in the area adjacent to alveolar bone and graft material surrounded by more dense connective tissue were found in 4 weeks. New bone formation up to crown portion was found and periodontal ligament was aligned functionally and cementum more mature. 4. Experimental II group, new bone formation was found under the defect area in 4 weeks and new bone formation around graft material in 8 weeks, too, and there were a number of fibroblasts, blood vessels, acellular cementum, which was less mature when compared to that of experimental I group, and dense collagen fiber like which normal periodontal ligament has in periodontal ligament of experimental II group in 8 weeks. 5. As a result of histologic finding, bone formation rate were 18.0${\pm}$7.87%(control group), 34. 05${pm}$7.25%(experimental I group), 19.33 ${pm}$5.15%(experimental II group) in 4 weeks and 21.89${pm}$1.58%(control group), 38.82${pm}$3.2(experimental I group), 37.65${pm}$9.22%(experimental II group) in 8 weeks. 6. Statistically significant ratio of bone formation was observed in experimental I group in 4 weeks and in experimental II group in 8 weeks. When experimental I group was compared to experimental II group, the ratio of bone formation in experimental I group was higher than that in experimental II group in 4 weeks(p<0.05). This results suggest that platelet-rich plasma showed more new bone formation than enamel matrix protein within 4 weeks. And use of enamel matrix protein in the treatment of periodontal bone defects starts to enhance regeneration after 8 weeks in beagle dogs.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.821-822
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• 2005