• Educational Technology International
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• v.16 no.2
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• pp.231-247
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• 2015

The purpose of this study was to identify the factors of ICT literacy in the primary school students in South Korea and to examine the gender and city size difference on the factor of ICT literacy. To accomplish this goal, we have analyzed the data of Korea Youth Competency Measurement and International Comparative Study I: ICCS 2016 which is nationally collected from the primary school students, currently on the 5 ~ 6th grades in South Korea. 1,188 samples were used in the study excluding missing samples. The participants were 584 5^th grad and 604 6^th grad students, 620 males (52.2%) and 568 females (47.8%). The mean age was 13.49 years (SD=.52). The result of the study reveals the four factors of ICT literacy through cross-validating exploratory factor analysis and confirmative factor analysis; pleasure of using ICT, perceived usefulness of using ICT, learning ability with using ICT, and operating ability of ICT. This study found that the leaner differ in gender on learning ability with using ICT and pleasure of using ICT. The female students were significantly larger than male students on learning ability with using ICT. However, the male students were significantly larger than male students on pleasure of using ICT. This study found that the leaner differ in city size on the factors of ICT literacy excluding pleasure of using ICT. The students living in the big size city were significantly larger than the students living in the middle and small. That is, over all, female students were more learning with ICT, male students were more interesting about ICT, and the students living in the big size city were more ICT use for learning. Based on the results, some strategies were suggested on the proper use of the factors of ICT in education.

• Journal of Microbiology
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• v.42 no.1
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• pp.25-31
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• 2004

Sf9 cells have obvious advantages for the conventional production technology of vaccine. They are useful tools for high concentration and large-scale cultures. Sf9 cells were grown to maximal concentration, 8${\times}$l0$\^$6/ cells/$m\ell$ in a 500$m\ell$ spinner flask, with a doubling time at the exponentially growing phase of 24.5 hours, using serum-free media. To explore the ability of Sf9 cells to be infected by the Japanese encephalitis (JE) virus Beijing-l strain, Sf9 cells were infected with the virus. By 4-5 days post-infection, 10-15 % of the Sf9 cells showed cytopathic effect (CPE), from granularity to the formation of syncytia and multinucleated giant cells continuously observed over a period of 35 days. Positive fluorescent reactions were detected in 30-40% of cells infected with the JE virus Beijing-l strain, and the uninfected Sf9 cells were completely negative. Virus particles, propagated in Sf9 and Vero cells, were concentrated by sedimentation on 40% trehalose cushions by ultracentrifugation, and showed identical patterns of viral morphogenesis. Complete virus particles, 40 to 50 nm in diameter, were observed, and JE virus envelope (E) proteins, at 53 kDa, were found in the western blot analysis to the anti-JE virus E protein monoclonal antibody and reacted as a magenta band in the same position to the glycoprotein staining. To evaluate whether the infectious virus was produced in Sf9 cells inoculated with the JE virus Beijing-l stain, Sf9 cells were inoculated with the virus, and sample harvested every 5 days. The titers of the JE virus Beijing-l strain rose from 1.0${\times}$l0$\^$5/ to 1.5${\times}$l0$\^$6/ pfu/$m\ell$. The infected Sf9 cells could be subcultured in serum-free medium, with no change in the plaque sizes formed by the JE virus Beijing-l strain in the plaque assay. It is suggested that the ability of the JE virus Beijing-l strain to infect Sf9 cells in serum-free media will provide a useful insect cell system, where the JE virus replication, cytopathogenicity and vaccine immunogen can be studied.

• Korean Journal of Poultry Science
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• v.7 no.1
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• pp.31-42
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• 1980

In order to identify the best superior cross combination of breeder stocks for broiler production, combining ability test and analyses of phenotypic performances for parent stocks were examined on records of 1,440 broiler chicken which were produced from 4 parental strains and 3 maternal strains at Hanhyup Poultry Breeding Farm from September 28, 1978 to January 5, 1979. The results obtained were as follows; 1. There was not found heterosis effect in viability but it seems to be desirable to select Hubbard strain in paternal line to improve viability. 2. As the paternal and maternal lines, selection of Ross strain showed the best paternal and maternal performance and the best general combining ability in body weight at 8 weeks of age is expected to be able to improve body weight of it s crossbred And the most superior cross combinations based on the specific combining ability and performance of rack crossbred were identified as Hubbard x Ross ana Ross x Hypeco crossbreds. 3. The best paternal and maternal lines on the smallest feed consumption for 8 weeks were Hubbard and Ross strains, and Hypeco strain, respectively. Especially Hubbard x Hypeco cross combination was proved as the smallest feed consumption compared with other cross combinations. 4. In feed requirement per Kg body weight increase, Hubbard strain for paternal line, Hypeco strain for naternal line, and cross combinations of Hubbard x Hypeco, Hubbard x Ross and Ross x Hypeco were certified as the most superiors. 5. Also superior cross combinations of Hubbard x Hypeco and Hubbard x Ross earned the most profit per bird through economic analysis. According to results as shown above, this experiment seems to be able to reach a such conclusion that production of superior cross combinations Hubbard x Ross, Hubbard x Hypeco and Ross x Hypeco through selection of Ross and Hubbard strains to paternal line and Hypeco and Ross strains for maternal line may become to considerable improvement for important economic characters of broiler; viability, body weight, feed consumption and feed requirement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.542-552
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• 2018

In this paper, the precast method of a concrete eco-pillar debris barrier was proposed to improve the construct ability and economic efficiency. The performance was validated by experimental and structural analysis. The steel debris barrier has a high construction cost and causes environmental damage with corrosion. The construction of a concrete eco-pillar debris barrier has been increased recently. On the other hand, there are no design standards regarding debris barriers in Korea, and debris barriers are being designed by the experience and sense of engineers. Therefore, in this study, a method to determine the design external forces was proposed and the design was performed by applying a hollow cross-section to the debris barrier. In addition, three types of connection methods of a concrete cantilever column with the maximum bending moment acts were proposed, and validation of the performance of each type was performed with a real-scale experiment. The experimental results showed that the type with loop reinforcement had the highest rigidity and the type with anchorage performance exceeded the maximum bending moment according to the ultimate load. In the manufacturing procedure of mock-up debris barriers, the type with an anchorage-bar was found to have superior construct ability.

• Korean Journal of Poultry Science
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• v.48 no.2
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• pp.69-80
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• 2021

We conducted a 4 × 4 diallel cross-mating test using 934 chickens from four grandparent stock lines to develop a new synthetic breed of Korean native chicken. The mean values, combining ability, and reciprocal effects on survival rate, body weight, and hen-day egg production were analyzed. In phenotypes, most chickens have yellowish-brown, reddish-brown and mixed color feathers. The average survival rate was 86.8±12.3%, with the highest in YH combination. Specific combining ability (SCA) had a greater effect on survival rate than general combining ability (GCA), and the SCA of HY combination was the highest. The 16 cross-combinations were distinctly divided into three weight groups according to their genetic characteristics. At 12 weeks of age, GCA showed a greater effect on weight than SCA, and the SCA of FH combination was the highest. The age at first egg laying was 157 days, and the crosses reached sexual maturity faster than the pure lines. The egg production rate was highest in SY at 79.5±2.1%. The GCA and SCA for hen-day egg production were similar, and the SCA was highest in the HS and FY combinations. The reciprocal effect showed that the offspring's egg production rate was high when S and Y were maternal parents in almost all combinations. In conclusion, FH and HF combinations, which have excellent growth performance, are the most desirable paternal parent stock strains, and FY, FS, HY, and SY combinations, which have excellent laying performance with moderate weight, are the preferred maternal strains.

• Journal of Chest Surgery
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• v.13 no.3
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• pp.186-197
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• 1980

We attempted to evaluate the effectiveness of cold blood potassium cardioplegia [Group B] compared with that of intermittent aortic cross clamp with topical hypothermia [Group A] in each six dogs. The studies were performed under the extracorporeal circulation with moderate hypothermia by using Mongrel dogs. 1. In Group A [6], it was difficult to maintain the temperature below 20?. but in Group B [6], it was possible to maintain the temperature. 2. In blood pressure and myocardial recovery ability, Group B was more excellent than Group A. 3. There was no significant difference in Na+, Ca++ and Cl- between both groups, but in K+ level, Group A was mild decreased and Group B was nearly normal level. 4. In serum LDH level, Group A was higher than Group B, but in SGOT level there was no significance between both groups. 5. On electromicroscopical study, Group A showed severe change in mitochondria, but Group B was nearly normal view. Thus we suggest that cold blood potassium cardioplegia would be more effective than intermittent aortic cross clamp with topical hypothermia for myocardial protection in open heart surgery.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.101.2-101.2
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• 2010

태양전지에서 고효율을 얻기 위해서는 알루미늄 원자의 확산에 의한 불순물층으로서 p+층이 필수적이다. P+층은 형성전자의 재결합을 방지하고, 생성 캐리어의 수집 효율을 향상시키는 BSF(Back Surface Field) 효과의 역할을 한다. 도포된 알루미늄 페이스트가 부족할 경우 BSF효과가 나타나지 않으며 과할 경우 웨이퍼가 휨이 발생하여 최적 인쇄도포량이 중요하다. 본 연구에서는 레오미터 측정조건을 스크린 프린팅 인쇄 조건과 유사하게 진행하여 저장탄성율(G') 과 손실탄성율(G")의 관계를 살펴보았다. 회복단계에서 G'>G" 이고 Cross point가 없을 경우 도포량이 1.8g 이상이였으며, 웨이퍼의 휨(bowing)이 크게 발생하였고, 이와 반대로 회복시 20초 후에 Cross point가 나타난 경우 10% 정도 도포량 감소와 함께 휨 발생도 1 mm 이하로 양호한 특성을 확인할 수 있었다.

• The Journal of Korean Physical Therapy
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• v.32 no.3
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• pp.163-167
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• 2020

Purpose: Unilateral strength training effects on contralateral sides have been demonstrated in previous studies for lower extremity exercise, upper extremity exercise, and unilateral surface electrical stimulation. This study was performed to investigate the effects of unilateral ankle training on muscle strength and the balance of contralateral lower extremity in healthy adults. Methods: Thirty healthy subjects were randomized equally to a training or a control group. Those in the training group received unilateral ankle isokinetic strengthening training of the dominant leg (right side) for 4 weeks. Contralateral single-limb balance, including Anterio-Posterior Stability Index (APSI), Medio-Lateral Stability Index (MLSI) and Overall Stability Index (OSI), was assessed before and after intervention. Results: Comparison of pre- and post-test data revealed significant improvements in ipsi- and contralateral ankle strengths, and significant improvement in contralateral single limb balance. Conclusion: These results have practical implications because they demonstrate that unilateral ankle isokinetic exercise improves ankle muscle strength and balance ability of contralateral lower extremity.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1995.10a
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• pp.68-75
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• 1995

The milling process is one of the most important metal removal processes in industry. Due to the complexities inherent to the cutter insert geometry and the milling cutter kinematics, these processes leave an analytically difficult to predict texture on the machined surface's hills and valleys. The instantaneous uncut chip cross sectional area may be estimated by the relative position between the workpiece and the cutter inserts. furthermore, since the cutting forces are proportional to the instantaneous uncut chip cross sectional area, the cutting forces in face milling operations can not be estimated easily. A new simulation program which is based upon the numerical method has been proposed to estimate the cutting force components, with the ability to predict the machined surface texture left by the face milling operation.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.4 no.4
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• pp.16-24
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• 1995

The milling process is one of the most important metal removal processes in industry. due to the complexities inherent to the cutter insert geometry and the milling cutter kinematics, these processes leave an analytically difficult to predict texture on the machined surface's hills and valleys. The instantaneous uncut chip cross sectional area may be estimated by the relative position between the workpiece and the cutter inserts. Furthermore, since the cutting forces are proportional to the instantaneous uncut chip cross sectional area, the cutting forces in face milling operations can not be estimated easily. A new simulation program which is based upon the numerical method has been proposed to estimate the cutting force components, with the ability to predict the machined surface texture left by the face milling.