• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1631-1633
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• 2001

In manufacturing processes, various and suitable pulse shapes are required for the purpose of material processing and the pulseshape is regarded as a dominant factor due to the specific property of processing materials. Therefore, in this study, a variable pulse width, high duty cycle Pulse Forming Network(PFN) is constructed by time sequently. The power supply for this experiment consists of three switching circuits. The PFN elements operate at low voltage and drive the primary of HV leakage transformer. The secondary of the transformer has a full-wave rectifier, which passes the pulse energy to the load in a continuous sequence of properly phased and nested increments. We investigated laser pulse width as various delay time among three switching circuit. As a result, we tan obtain various laser pulse width from about 4ms to 10ms. The maximum laser pulse width obtained at this experiment was about 10ms at delay time of 4ms among each switching circuit.

• International Journal of Advanced Culture Technology
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• 제2권1호
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• pp.20-24
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• 2014

As the standards organization under ISO responsible for the development of all international financial services standards, ISO/TC 68 plays a key role in the development and adoption of new technologies in the banking, brokerage and insurance industries. In this paper many of its current work projects are introduced for developing ecommerce standards. We need to discuss the recommendations on XML conversion with ISO and other international standard organizations. Each country try to adopt the international standards even though domestic technical standards and barriers. To solve this problem of interworking between these standards, harmonization activities are nedded. For development and distribution of electronic documents to be conformed to international standards, it is enough to have the role of international activities continue to supply part of the domestic industry and the trends in participation and international standard.Our principal focus is on facilitating national and international trade, through the simplification and harmonization of processes, procedures and information flows, and so contributing to the growth of global commerce.

• 대한조선학회논문집
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• 제57권2호
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• pp.70-79
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• 2020

The offshore installation units may be subjected to various accidental loads such as collision from supply vessels, impact from dropped objects, blast load from gas explosion and thermal load from fire. This paper deals with the design and strength evaluation method of the stiffened plate structures in response to a blast load caused by a gas explosion accident. It is a comprehensive review of various items used in actual project such as the size and type of the explosive loads, general design procedure/concept and analysis method. The structural analyses using simple analysis methods based on SDOF model and nonlinear finite element analysis are applied to the particular FPSO project. Also validation studies on the design guidance given by simple analysis method based on SDOF model have also considered several items such as backpressure effects, material behavior and duration time of the overpressure. A good correlation between the prediction made by simple analysis method based on SDOF model and nonlinear finite element analysis can be generally obtained up to the elastic limit.

• STI Policy Review
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• 제1권3호
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• pp.17-24
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• 2010

Energy consumption is the largest contributing factor for the increase of $CO_2$ emissions and amounts for almost 85% of all emissions. The future energy consumption of Korea is projected to grow exponentially despite its heavy dependence on imported energy that represents 97% of its total energy supply. According to a recent OECD report the carbon emission level of Korea is currently ranked 9th in $CO_2$ emissions, and is growing by almost 3% every year. Against this background, the Korean government introduced the "low carbon green growth" policy in 2008. As the global challenges intensified in the wake of the world economic crisis, Korea has been working hard in raising the visibility of its efforts at the club governance meetings, in particular the G-20 summit. Because of cooperative efforts with major member countries, the G-20 summit agenda has been significantly diversified to include long-term issues such as climate change, development issues, and global health. To achieve an effective green recovery for a new green world economic order, the G-20 summit leaders should concentrate on a strategy of establishing green governance for a global STI cooperation. Korea as the host country is poised to leverage the Seoul G-20 summit to catalyze global efforts toward a new green economic order.

• 한국주조공학회지
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• 제29권5호
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• pp.238-243
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• 2009

This study has been carried out to investigate the cooling ability improvement of diecasting mold by decompression cooling system. The decompression cooling system was applied to the new/used oil pump cover molds. The temperature of the surface mold applied the decompression cooling system fell to 15 degrees, especially in case of the used mold. The defect ratio of the oil pump cover manufactured by decompression cooling system has decreased from 2.8 percent to 0.2 percent. According to the results of the cooling ability improvement of diecasting mold by decompression cooling system, the decompression degree and supply pressure were set up the control item to apply the decompression cooling system to the diecasting mold in the industry field.

• 한국정밀공학회지
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• 제13권12호
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• pp.30-37
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• 1996

On-line process control equipment for CO$_{2}$ laser cutting is not available for industrial applications. The major part of the industrial laser cutting machines are adjusted off-line by highly educated engineers. The quality inspection of the sample is visual and referred to different quality scales. Due to the lack of automation the potential laser users hesitate to implement the cutting method. The first step toward an automation of the process is the development of a process monitoring system and the research is cincentrated on the area of on-line quality monitoring during CO$_{2}$ laser cutting. The method is based on the detection of the emitted light from the cutting front by photo diode. The developed monitoring system consists of the OP Amplifier, A/D convertor, power supply and PC. The signal from the photo diode has been undertaken from Fourier analysis and statistical analysis with real time. The photograph of striation pattern was taken by metallurgical microscope. As a result, it is possible to predict the striation pattern according to the beam traveling speed.

• Asian Journal of Innovation and Policy
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• 제12권2호
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• pp.246-260
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• 2023

With the advent of COVID-19, the world economy has undergone enormous losses and unprecedented crises. Moreover, this pandemic has put a significant effect on all business organizations, comprising the micro, small and medium enterprises (MSMEs) sector. MSMEs have been continuing to develop business strategies and are eager to compete in the market. The COVID-19 pandemic has shifted the full focus of MSMEs from 'business growth' to 'business survival' worldwide. E-commerce readiness plays a crucial role in a time of uncertainty and crisis during COVID-19 and affects the durability and sustainability of the business. This study attempts to study the readiness of online business and "E-commerce" adoption of MSMEs and its contribution to economic growth by utilizing both qualitative and quantitative techniques in the case of India. We use content analysis to determine the readiness of online business and Ecommerce in the post COVID-19 period. The result highlights the specific issues of this sector such as the shortage of resources and disruptions in the supply chain & logistical issues during the COVID-19 pandemic. Qualitative analysis discloses that almost half of the respondents adopt online platforms along with additional challenges to sustain their business during the pandemic. This study utilizes annual time series data for the period from 1973-74 to 2017-18 to understand the long-run relationship between India's GDP and MSMEs units. By utilizing the co-integration technique, this study reveals that there is a long-run relationship between MSME units and the economic growth of this country.

• Korean Chemical Engineering Research
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• 제57권3호
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• pp.400-407
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• 2019

순산소 순환유동층 연소기술은 기후변화 및 연료 수급 문제들을 해결할 수 있는 기술로 주목 받고 있다. 순산소 순환유동층 연소기술은 배기가스재순환 공정을 통해 이산화탄소를 비교적 쉽게 포집할 수 있으며 대기오염물질 배출도 줄일 수 있는 친환경 연소기술이다. 새롭게 개발된 $100kW_{th}$ 급 순산소 순환유동층 연소 시스템은 연료다변화에 대응하기 위해 다양한 연료들의 순산소연소 특성을 분석하고 있으며, 본 연구에서는 높은 고정탄소 및 회분함량으로 인해 연소성이 낮은 연료로 알려진 무연탄을 활용하여 높은 이산화탄소를 생산하고 연소효율을 향상시키고자 하였다. 그 결과로서, 무연탄 순산소 연소는 아역청탄 공기연소 대비, 연소효율이 2% 향상되었으며 대기오염물질인 $SO_2$, CO, NO은 각각 15%, 60%, 99% 감소하였다. 또한, 안정적인 순산소순환유동층 연소를 통해 배기가스 내 94 vol.% 이상의 $CO_2$ 가 포집될 수 있음을 확인하였다.

• Journal of Nutrition and Health
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• 제29권3호
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• pp.267-277
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• 1996

Effect of DHA-rich fish oil on brain development and learning ability has been studied in Sprague Dawley rats. Female rats were fed experimental diets containing either corn oil fish oil at 10%(w/w) level throughout the gestation and lactation. Corn oil was added in fish oil diet to supply essential fatty acid at 2.3% of the calories. All male pups were weaned to the same diets of dams at 21-days after birth. Plasma fatty acid composition was analyzed for dams and pups at 21-days, 28-days and 22-weeks after birth. The analysis of DNA and fatty acid profile in the brain were undertaken at birth, 3, 7, 14, 21, 28 days and 22 weeks after birth and learning ability was tested at 18-20 weeks of age. Regardless of dietary fats, arachidonic acid(AA) and docosahexaenoic acid(DHA) were the principal polyunsaturated fatty acids in the brain. Rats fed CO diet showed a continouus increase of AA content in the brain from 10.9%(at birth) to maximum 15.3% level (14-days old), while the rars fed FO diet showed 78-79% of CO group throughout the period. Rats fed FO diet showed higher incorparation of DHA from 15.2% at birth to a maximum level of 18.5% at 140days, while the rats fed CO diet showed only 7.0% incorporation of DHA at birth and a maximum level of 11.1% at 21-days. Compared to CO group, FO group showed lower ratio of chol/PL and higher content of DHA in brain microsomal membrane, resulting in better membrane fluidity. Total amount of DNA per gram of brain was reached maximum level at 21 days in both groups. This would be a period of the cell proliferation during brain development. Overall, the rats fed fish oil diet showed a higher incorporation of DHA and membrane fluidity in the brain and better learning performances (p<0.05).

• KSBB Journal
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• 제13권1호
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• pp.96-100
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• 1998

두 개의 프로모터 (trc와 Pp)를 Alcaligenes eutrophus에서 유래된 PHA 오페론에 삽입하여 재조합 대장균에서 분자량이 큰 polyhydroxybutyrate (PHB)를 얻고자 하였다. 두 개의 프로모터는 hydroxybutyric CoA와 PHA 중합반응의 유전자 발현을 각각 독립적으로 제어하기 위해 설계된 것이다 새로운 합성오페론을 포함한 플라즈미드는 E. coli DH5 $\alpha$ 에 transformation 되어 PHB 생산에 이용되었다. 본 실험의 가설로서 PHA 합성오페론의 IPTG에 의한 유도가 없을 경우 낮은 pHA synthase의 활성이 고분자 중합반응의 개시제 농도를 줄여주어 결과적으로 높은 연결수의 고분자를 생성할 것이라는 모델을 세웠다. 실제로 IPTG의 공급이 없는 발효실험을 통해 평균분자량이 $2.5{\times}10^7$ 인 거대 고분자를 얻을 수 있었다. PHA 생합성에 관여는 효소의 활성 분석으로 3-hydroxybutyric CoA의 중합을 촉매하는 효소인 PHA synthase의 활성을 가지고 In vivo에서 분자량이 제어됨을 확인하였다.