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AN EXPERIMENTAL STUDY ON THE EFFECT OF Ca(OH)2 UPON THE HEALING PROCESS OF THE PULP AND PERIAPICAL TISSUE IN THE DOGS' TEETH (수산화칼슘이 손상치수조직 및 치근조직의 치유에 미치는 영향에 관한 연구)

  • Lim, S.S.;Yoon, S.H.;Lee, C.S.;Lee, M.J.;Kim, Y.H.;Kwon, H.C.;Um, C.M.
    • Restorative Dentistry and Endodontics
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    • v.8 no.1
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    • pp.123-131
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    • 1982
  • The purpose of this study was to observe the responses of the remaining pulp tissue after pulpotomy upon the several kinds of $Ca(OH)_2$ products and the responses of periapical tissue upon some root canal filling materials after extirpation. For pulpotomy, the class V cavities were prepared on the premolars, molars and upper canines, and the pulp was amputated. Each drug was placed over the amputated tissue and cavity was sealed with zinc oxide eugenol cement. The drugs which were used for the study were Dycal (Caulk Co. U.S.A.), Cavitec (Kerr Co. U.S.A.), Calvital, Nobudyne and Neodyne (Neo Dental Chemical Products). For extirpation, the endodontic cavities were prepared on the lingual surfaces of anterior teeth, and the pulp tissues were extirpated as routine method. After enlarging, irrigation, and measuring of root length by taking X-ray, each root canal filling material was filled in the canal with gutta percha cone, and endodontic cavity was sealed with zinc oxide eugenol cement. Zinc oxide eugenol, $Ca(OH)_2$ (Eli Lilly Co. U.S.A.) and Vitapex (Neo Dental Chemical Products) were used as root canal filling materials. Animals were sacrificed after 1, 3 and 6 weeks following the operation. The teeth were decalcified in formic acid, sectioned and stained with hematoxylin eosin. Microscopic examination revealed as follows. 1. Dycal: The dentin bridge formation was observed at the 3rd week after pulpotomy. Inflammatory conditions which were infiltration of inflammatory cells and dilatation of blood vessels were kept in remaining pulp tissue at the 6th week. 2. Calvital: The dentin bridge was observed at the 1st week after pulpotomy. As the time clasped, the pulp tended to be the fibrous degeneration. 3. Cavitec, Nobudyne and Neodyne: In the case of Cavitec and Nobudyne, the incompleted and irregular dentin bridge was observed at the 6th week, and in Neodyne, was observed at the 3rd week. The severe inflammatory changes were seen in the remaining pulp tissue. As the time clasped, the fibrous degeneration tended to spread in the remaining pulp tissue. 4. $Ca(OH)_2$: Osteocementum was formed at the 3rd week, the matrix of cementum and dentin were resorted, and infiltration of lymphocytes was seen in periapical tissue when $Ca(OH)_2$ was used as canal-filling materials. S. ZOE and Vitapex The cementum like substance was seen in periapical portion at the 1st week, when ZOE and Vitapex were used as root canal filling materials. As the time elapsed, the matrix of cementum and dentin tended to be resorted. At the 6th week, the inflammatory condition of periapical tissue was continued in the case of ZOE, but was reduced in the case of Vitapex.

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Impacts of Collaborative Problem Solving for Character Competency (CoProC) Strategy on the Practical Character Competency and Collaborative Problem Solving Competency in Middle School Science (협력적 문제해결(CoProC) 전략을 통한 중학생의 실천적 인성 역량 및 협력적 문제해결력의 함양)

  • Cho, Hye Sook;Kwon, Dong Uk;Kang, Eugene;Park, Jongseok;Son, Jeongwoo;Nam, Jeonghee
    • Journal of The Korean Association For Science Education
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    • v.38 no.5
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    • pp.681-691
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    • 2018
  • The purpose of this study is to investigate the impacts of Collaborative Problem solving for Character competency (CoProC) strategy on the practical character competency and collaborative problem solving competency in middle school. For this study, 49 seventh grade students (two classes) were selected for use applying the CoProC strategy (CoProC group) while 46 students (two classes) were used for traditional lecture and experimental class (comparative group). In the result, CoProC group showed a statistically significant result in practical character competency than the comparative group. In the sub items of the competency, the CoProC group showed result statistically significant in cooperation, communication, responsibility, and positive self-understanding than the comparative group. Analysis of the effect size of students' practical character competency showed that the CoProC group results showed more effective than the comparative group in terms of care, cooperation, communication, honesty, responsibility, positive self-understanding, and self-regulation. In addition, we investigated the effect of the CoProC strategy on collaborative problem solving competency. As a result, it showed a large effect in the total score of collaborative problem solving competency. Among the sub items of the competency, 'exploration and understanding of members' showed a small size of effect and 'Establishing and maintaining team organization' showed a medium size of effect. 'Communication' and 'self-reflection' showed a large effect. CoProC strategy embedded in Science subject could improve students' collaborative problem solving competency through the process of scientific communication in the scientific inquiry process.

A Study on the Development of Multimedia CAI in Smoking Prevention for Adolescents (청소년 흡연예방을 위한 멀티미디어 CAI 개발)

  • Lee, Sook-Ja;Park, Tae-Jin;Joung, Young-Il;Cho, Hyun
    • Korean Journal of Health Education and Promotion
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    • v.20 no.2
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    • pp.35-61
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    • 2003
  • Background: The purpose of this study was to develop a structured and individualized smoking prevention program for adolescents by utilizing a multimedia computer-assisted instruction model and to empirically assess its effect. Method: For the purpose of this study, a guide book of smoking prevention program for middle and high school students was developed as the first step. The contents of this book were summarized and developed into an actual multimedia CAI smoking prevention program according to the Gane & Briggs instructional design and Keller's ARCS motivation design models as the second step. At the final step, the short-tenn effects of this program were examined by an experiment. This experiment were made for middle school and high school students and the quasi experimental design was the pretest - intervention - posttest. The measured data was attitude, belief, and knowledge about smoking, interest in the program, and learning motivation. Result: The results of this study were as follows: First, the guide book of a smoking prevention program was developed and the existing literature on adolescent smoking was analyzed to develop the content of the guide book. Then the curriculum was divided into three main domains on tobacco and smoking history, smoking and health, adolescent smoking and each main domain was divided into sub-domains. Second, the contents of the guide book were translated into a multimedia CAI program of smoking prevention througn Powerpoint software according to the instructional design theory. The characteristics of this program were interactive, learner controllable, and structured The program contents consisted of entrance(5.6%), history of tobacco(30%), smoking and health(38.9%), adolescent smoking(22.2%), video(4.7%), and exit(1.6%). Multimedia materials consisted of text(121), sound and music, image(still 84, dynamic 32), and videogram(6). The program took about 40 minutes to complete. Third, the results on analysis of the program effects were as follows: 1) There was significant knowledge increase between the pre-test and post-test with total mean difference 3.44, and the highest increase was in the 1st grade students of high school(p<0.001). 2) There was significant decrease in general belief on smoking between the pre-test and post-test with total mean difference 0.28. In subgroup analysis, the difference was significantly higher in the 1st grade of high school (p<0.001), low income class (p<0.001), and daily smokers (p<0.01). 3) There was no significant difference in attitudes on his personal smoking between the pre-test and post-test. 4) The interest in the program seemed to lower as students got older. The score of motivation toward this prevention program was the highest in the middle school 3rd grade. Among sub-domains of motivation, the confidence score was the highest. Conclusion: To be most effective, the smoking prevention program for adolescents should utilize the most up-to-date and accurate information on smoking, and then instructional material should be developed so that the learners can approach the program with enjoyment. Through this study, a guide book with the most up-to-date information was developed and the multimedia CAI smoking prevention program was also developed based on the guide book. The program showed positive effect on the students' knowledge and belief in smoking.

A Study on the Landscape-Oriented Persuasive Language from Naming the Apartment Brand in Korea - Focus on the Analysis of Category and Lexeme - (국내 아파트브랜드 명명(命名)에 담긴 조경지향적 설득언어 - 유형 및 어휘소 분석을 중심으로 -)

  • Rho, Jae-Hyun
    • Journal of the Korean Institute of Landscape Architecture
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    • v.38 no.1
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    • pp.49-63
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    • 2010
  • This study was intended to analyze and interpret the pattern of naming the domestic apartment brand from a semiologic viewpoint in a bid to review the meaning and value of apartment brand, while on the other hand, evaluating the characteristics of persuasive message pursued by current apartment brand in 2010, and consequently, the conclusion of the study is outlined as follows. 1. As a result of analyzing the coinage of branding naming, the words such as combination, joint and blending pattern tended to dominate, which seemed to attempt to represent the variety of values of the housing culture. Brand ideation tends to stress the character symbolism and polysemic message using syllepsis, and the experimental attempt to revive the traditional dwelling concept in a modern sense in a way of combining the archaic word with the Chinese character was found as well. 2. As a result of analyzing the frequency of verbal identity and lexeme of domestic apartments, those frequently used are in order of ville, nature, beauty(美), park, hi, green, palace(宮), nobility and center(tra), which are the lexemes representing the landscape, view, nature and dignity. 3. As a result of identifying the pattern of lexeme using analysis frame based on existing researches such as apartment brand positioning, the most important external core concepts controlling the direction and value of apartment brand are 'environment-orientated' and 'emotion-orientated', and internally, 'function-oriented'. Given the persuasive language expressing the 'environment-oriented' feature and the priority of brand lexeme are garden, park, view and the nature, a landscape-oriented persuasive message is seen to be surging in brand naming. 4. An emotion-oriented persuasive language such as dignity axis having major lexeme represented by palace, nobility, class and a pride axis having major semantic elements represented by human, I and you are used as major value concepts and persuasive language that lead domestic apartment brands to differentiation and upgradation. 5. Among the lexemes focusing on view from environment-oriented standpoint, hi, hill, tower, view, mark, heights are the trend pursued by high-rise apartment aiming at the view such as residential-commercial apartment, and thus the persuasive language focusing on high-rise concept is expected to become the element dominating the trend of apartment brand for the time being.

Bronchial Responsiveness in Patients with Mitral Valvular Heart Disease (승모판 심장질환 환자에서 기관지 반응성에 대한 연구)

  • Kim, Ho-Cheol;Kim, Min-Gu;Hwang, Young-Sil
    • Tuberculosis and Respiratory Diseases
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    • v.42 no.5
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    • pp.752-759
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    • 1995
  • Background: Bronchial asthma is characterized by noctunal dyspnea, cough and wheezing because of airway hyperresponsiveness to nonspecific stimuli. These symptoms and signs are also observed in patients with congestive heart failure. Therefore, this is so called "cardiac asthma". There are lots of experimental and clinical datas to suggest that airway dysfunctions occur in acute and chronic congestive heart failure. However, it is still controversial whether bronchial hyperresponsiveness is present in patients with congestive heart failure. To assess whether bronchial hyperresponsiveness is present in patients with congestive heart failure and to demonstrate the relationship between bronchial responsiveness and vascular pressure, we performed methacholine provocation test in 11 patients with mitral valvular heart disease. Methods: All patients were in the New York Heart Association functional class II and treated continuously with digoxin and/or dichlozid and/or angiotensin converting enzyme inhibitor except one patient. All patients were undergone right and left side heart catheterization for hemodynamic measurements. A 20 percent fall of peak expiratory flow rate were considered as positive response to methacholine provocation test. Results: 1) Only one patient who has normal pulmonary artery pressure, pulmonary capillary wedge pressure, cardiac index was positive in methacholine provocation test. 2) Their mean pulmonary artery pressure, pulmonary capillary wedge pressure were $21.72{\pm}9.70mmHg$, $15.45{\pm}8.69mmHg$ respectively which were significantly higher. Conclusion: It is speculated that in stable congestive heart failure patients, bronchial responsiveness as assessed by methacholine provocation test may not be increased.

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A Study on the Effects of Creative STEAM System Given by Center of Gravity Experiment (창의적 융합교육을 위한 무게중심 프로그램 개발과 적용사례 연구)

  • Kim, Su Geum;Ryu, Shi Kyu;Kim, Sun Bae
    • Journal of Educational Research in Mathematics
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    • v.24 no.3
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    • pp.333-357
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    • 2014
  • This study resulted from a study regarding creative STEAM System based upon an experiment with the center of gravity. The results of the study are constructed by a fusion of mathematics and physics, showing that they are the same as mathematical calculations. Also, students can find that center of gravity of an object is in equilibrium on a metal rod when the center of gravity exactly is placed on the rod. The fact that an experimental results are correspond to calculations can maximize the effectiveness of teaching. And also this study has the following effectiveness. First, the exact construction and calculations arouses good competition among students. Second, this experiment can give students a motivation for study and increase their thinking in classes because the theoretical background of center of gravity experiment is basically attributed to math and science classes in school. This study includes three different types of center-of-gravity experiments. One is a simple type of experiment in which center of gravity exists inside of an object. Another is a complicated one in which the center of gravity is also inside of an object. However, the third type is an experiment in where the center of gravity is outside of an object. Therefore, it gives students an opportunity to discuss how to confirm equilibrium on a metal rod when the object has its center of gravity outside. Having discussions in class will allow students to have a critical way of thinking. In addition, searching for a way to solve a problem will increase creativity of students as well. And the last type is finding the center of gravity of a big acrylic panel where multiple objects are on the panel. According to the survey and interview conducted by students who participated in this program, teaching based on creative STEAM system helps students to get a better understanding and more fast acquisition of knowledge. We can expect that a well-planned creative STEAM system through a continuous study will be both effective and efficient in educating critical and creative students.

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Effect of cavity shape, bond quality and volume on dentin bond strength (와동의 형태, 접착층의 성숙도, 및 와동의 부피가 상아질 접착력에 미치는 영향)

  • Lee, Hyo-Jin;Kim, Jong-Soon;Lee, Shin-Jae;Lim, Bum-Soon;Baek, Seung-Ho;Cho, Byeong-Hoon
    • Restorative Dentistry and Endodontics
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    • v.30 no.6
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    • pp.450-460
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    • 2005
  • The aim of this study was to evaluate the effect of cavity shape, bond quality of bonding agent and volume of resin composite on shrinkage stress developed at the cavity floor. This was done by measuring the shear bond strength with respect to iris materials (cavity shape , adhesive-coated dentin as a high C-factor and Teflon-coated metal as a low C-factor), bonding agents (bond quality: $Scotchbond^{TM}$ Multi-purpose and Xeno III) and iris hole diameters (volume; 1mm or 3mm in $diameter{\times}1.5mm$ in thickness). Ninety-six molars were randomly divided into 8 groups ($2{\times}2{\times}2$ experimental setup). In order to simulate a Class I cavity, shear bond strength was measured on the flat occlusal dentin surface with irises. The iris hole was filled with Z250 restorative resin composite in a bulk-filling manner. The data was analyzed using three-way ANOVA and the Tukey test. Fracture mode analysis was also done When the cavity had high C-factor, good bond quality and large volume, the bond strength decreased significantly The volume of resin composite restricted within the well-bonded cavity walls is also be suggested to be included in the concept of C-factor, as well as the cavity shape and bond quality. Since the bond quality and volume can exaggerate the effect of cavity shape on the shrinkage stress developed at the resin-dentin bond, resin composites must be filled in a method, which minimizes the volume that can increase the C-factor.

Installation Art In Indonesian Contemporary Art; A Quest For Medium and Social Spaces (인도네시아 현대미술에 있어서의 설치미술 - 미디엄과 사회적 공간을 위한 탐색)

  • Kusmara, A. Rikrik
    • The Journal of Art Theory & Practice
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    • no.5
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    • pp.217-229
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    • 2007
  • Many historical research and facet about modern art in Indonesia which formulating background of contemporary Indonesian Art. Indonesian art critic Sanento Yuliman states that Modern art has been rapidly developing in Indonesia since the Indonesian Independence in 1945. Modern Art is a part of the super culture of the Indonesian metropolitan and is closely related to the contact between the Indonesian and Western Cultures. Its birth was part of the nationalism project, when the Indonesian people consists of various ethnics were determined to become a new nation, the Indonesian nation, and they wished for a new culture, and therefore, a new art. The period 1960s, which was the beginning of the creation and development of the painters and the painters associations, was the first stage of the development of modern art in Indonesia. The second stage showed the important role of the higher education institutes for art. These institutes have developed since the 1950s and in the 1970s they were the main education institutes for painters and other artists. The artists awareness of the medium, forms or the organization of shapes were encouraged more intensely and these encouraged the exploring and experimental attitudes. Meanwhile, the information about the world's modern art, particularly Western Art; was widely and rapidly spread. The 1960s and 1970s were marked by the development of various abstractions and abstract art and the great number of explorations in various new media, like the experiment with collage, assemblage, mixed media. The works of the Neo Art Movement-group in the second half of the 1970s and in the 1980s shows environmental art and installations, influenced by the elements of popular art, from the commercial world and mass media, as well as the involvement of art in the social and environmental affairs. The issues about the environment, frequently launched by the intellectuals in the period of economic development starting in the 1970s, echoed among the artists, and they were widened in the social, art and cultural circles. The Indonesian economic development following the important change in the 1970s has caused a change in the life of the middle and upper class society, as has the change in various aspects of a big city, particularly Jakarta. The new genre emerged in 1975 which indicates contemporary art in Indonesia, when a group of young artists organized a movement, which was widely known as the Indonesian New Art Movement. This movement criticized international style, universalism and the long standing debate on an east-west-dichotomy. As far as the actual practice of the arts was concerned the movement criticized the domination of the art of painting and saw this as a sign of stagnation in Indonesian art development. Based on this criticism 'the movement' introduced ready-mades and installations (Jim Supangkat). Takes almost two decades that the New Art Movement activists were establishing Indonesian Installation art genre as contemporary paradigm and influenced the 1980's gene ration like, FX Harsono, Dadang Christanto, Arahmaiani, Tisna Sanjaya, Diyanto, Andarmanik, entering the 1990's decade as "rebellion period" ; reject towards established aesthetic mainstream i.e. painting, sculpture, graphic art which are insufficient to express "new language" and artistic needs especially to mediate social politic and cultural situation. Installation Art which contains open possibilities of creation become a vehicle for aesthetic establishment rejection and social politics stagnant expression in 1990s. Installation art accommodates two major field; first, the rejection of aesthetic establishment has a consequences an artists quest for medium; deconstruction models and cross disciplines into multi and intermedia i.e. performance, music, video etc. Second aspect is artists' social politic intention for changes, both conclude as characteristics of Indonesian Installation Art and establishing the freedom of expression in contemporary Indonesian Art until today.

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Investigation on Diesel Injection Characteristics of Natural Gas-Diesel Dual Fuel Engine for Stable Combustion and Efficiency Improvement Under 50% Load Condition (천연가스-디젤 혼소 엔진의 50% 부하 조건에서 제동효율 및 연소안정성 개선을 위한 디젤 분무 특성 평가)

  • Oh, Sechul;Oh, Junho;Jang, Hyungjun;Lee, Jeongwoo;Lee, Seokhwan;Lee, Sunyoup;Kim, Changgi
    • Journal of the Korean Institute of Gas
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    • v.26 no.3
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    • pp.45-53
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    • 2022
  • In order to improve the emission of diesel engines, natural gas-diesel dual fuel combustion compression ignition engines are in the spotlight. In particular, a reactivity controlled compression ignition (RCCI) combustion strategy is investigated comprehensively due to its possibility to improve both efficiency and emissions. With advanced diesel direct injection timing earlier than TDC, it achieves spontaneous reaction with overall lean mixture from a homogeneous mixture in the entire cylinder area, reducing nitrogen oxides (NOx) and particulate matter (PM) and improving braking heat efficiency at the same time. However, there is a disadvantage in that the amount of incomplete combustion increases in a low load region with a relatively small amount of fuel-air. To solve this, sensitive control according to the diesel injection timing and fuel ratio is required. In this study, experiments were conducted to improve efficiency and exhaust emissions of the natural gas-diesel dual fuel engine at low load, and evaluate combustion stability according to the diesel injection timing at the operation point for power generation. A 6 L-class commercial diesel engine was used for the experiment which was conducted under a 50% load range (~50 kW) at 1,800 rpm. Two injectors with different spray patterns were applied to the experiment, and the fraction of natural gas and diesel injection timing were selected as main parameters. Based on the experimental results, it was confirmed that the brake thermal efficiency increased by up to 1.3%p in the modified injector with the narrow-angle injection added. In addition, the spray pattern of the modified injector was suitable for premixed combustion, increasing operable range in consideration of combustion instability, torque reduction, and emissions level under Tier-V level (0.4 g/kWh for NOx).

The Effect of Small-Scale Chemistry (SSC) Lab Program with Respect to High School Students' Extroversions and Introversions (고등학생의 내.외향성에 따른 SSC(Small-Scale Chemistry) 실험 수업의 효과)

  • Yoo, Mi-Hyun;Kim, Mi-Young;Hong, Hun-Gi
    • Journal of The Korean Association For Science Education
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    • v.29 no.2
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    • pp.179-192
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    • 2009
  • The purpose of this study was to examine the effects of Small-Scale Chemistry (below SSC) Lab Program with respect to students' extroversions and introversions. For this study, an SSC Lab Program was developed on the basis of analyzing the chemistry part of the high school science textbook in the 7th curriculum. The experimental group received SSC experiment lessons, and the comparison group received traditional experiment lessons based on textbook for 5 class periods. Afterwards, students were grouped into extrovert and introvert according to their personality test scores, the differences between the two groups were investigated using 2-way ANCOVA. Prior to the instructions, three test regarding the scientific attitude and academic self-efficacy were administered. After the instructions, the scientific attitude, academic self-efficacy, and students' perceptions on SSC Lab Program were examined. The scores in mid-term and end-of-term science exams were used as pre-test and post-test science achievement scores, respectively. Two-way ANCOVA results revealed that there were effects in the score of the academic achievement score, but there was no interactive effect between extroversion/introversion and treatment. In addition, a significant interactive effect was found in the scientific attitude, but there was no significant main effect. It was interpreted that extrovert students had many opportunities in SSC experiment classes and were able to experiment with initiative, but introverts would feel the responsibility and the pressure owing to the small group experiment. There were no main and interactive effects in the score of the academic self-efficacy test. Survey of students' perceptions on SSC Lab Program revealed that both over 90% extrovert and introvert students showed very positive perceptions in 'three-membered small group composition,' 'understanding,' and 'convenience' items. It was found to be a very different perception between extrovert and introvert students in 'comparing result with other students' item.