• 한국안전학회지
• /
• 제15권3호
• /
• pp.66-70
• /
• 2000

In order to cope with environmental problems caused by harmful gases emitted from various industrial sources, a new technology which employs discharge plasma formed in ordinary atmospheric pressure has been intensively investigated in many industrialized nations. Although a plenty of useful outcomes and suggestions have been made public by scientists in this field, few commercial products which effectively decompose pollutant gases have appeared as yet. This is partly because that the energy efficiency of a most effective plasma reactor has not reached a satisfactory level in comparison with those of devices using conventional technologies. In an attempt to solve the problem mentioned above, we noticed to combine heterogeneous electrical discharges. This concepts is based on that each plasma reactor has its specific spatial region in which chemical reaction are active and by electrically affected with another reactor of different type, the activated region would increase - which may lead to cutting down the energy consumption. To prove this concept experimentally, two different discharge equipments, a plane ceramic-based surface discharge electrode and a corona electrode with tungsten needle may, are selected and combined to fabricate a hybrid plasma reactor. The results are summarized as follows; (1) Ozone concentration generated in the plasma region drastically increases when the positive corona discharge is added to the surface discharge. The rate of increase of ozone depends on the frequency of the surface discharge. The negative corona, however, does not contribute to the improvement of the ozone generation. (2) NO(nitrogen monoxide) decomposition rate also improves by simultaneously applying the surface and the positive corona discharges. The effect of the corona superposition is more evident when the level of the surface discharge is moderate. (3) By adjusting the corona level, the net energy efficiency during NO decomposition improves in comparison with the simple surface discharge reactor.

• 융합정보논문지
• /
• 제9권9호
• /
• pp.33-37
• /
• 2019

본 '클라우드컴퓨팅 발전 및 이용자 보호에 관한 법률'이 시행됨에 따라 이에 맞추어 국내 공공 및 민간기업에서 클라우드 컴퓨팅이라는 새로운 패러다임에 대한 관심이 고조되고 있다. 국내 클라우드 시장 선점을 위해서는 국내 통신사, SI 및 SW업체 등이 시장에 진출하고 있으나 글로벌 기업에 비해 경쟁력이 낮다. 따라서 국내기업은 국내시장에 특화된 SaaS 제품 개발을 하고 글로벌 기업에 앞선 IaaS 시장 선점을 위해 노력해야 할 것이다. 본 논문에서는 클라우드 컴퓨팅 개념과 G-클라우드의 클라우드관리시스템(G-CMS) 구축사례를 통해 향후 관련 산업의 발전방향 전망에 대해 알아본다. G-CMS는 이기종 Unix 가상화 시스템을 종합적으로 관리하는 최초의 시스템으로 볼 수 있습니다. 또한 G-CMS는 데이터 센터에서 이기종 가상화 시스템을 관리함으로써 비용을 절감할 수 있습니다.

• Journal of Microbiology and Biotechnology
• /
• 제31권1호
• /
• pp.8-15
• /
• 2021

More and more available fungal genome sequence data reveal a large amount of secondary metabolite (SM) biosynthetic 'dark matter' to be discovered. Heterogeneous expression is one of the most effective approaches to exploit these novel natural products, but it is limited by having to clone entire biosynthetic gene clusters (BGCs) without errors. So far, few effective technologies have been developed to manipulate the specific large DNA fragments in filamentous fungi. Here, we developed a fungal BGC-capturing system based on CRISPR/Cas9 cleavage in vitro. In our system, Cas9 protein was purified and CRISPR guide sequences in combination with in vivo yeast assembly were rationally designed. Using targeted cleavages of plasmid DNAs with linear (8.5 kb) or circular (8.5 kb and 28 kb) states, we were able to cleave the plasmids precisely, demonstrating the high efficiency of this system. Furthermore, we successfully captured the entire Nrc gene cluster from the genomic DNA of Neosartorya fischeri. Our results provide an easy and efficient approach to manipulate fungal genomic DNA based on the in vitro application of Cas9 endonuclease. Our methodology will lay a foundation for capturing entire groups of BGCs in filamentous fungi and accelerate fungal SMs mining.

• KDI Journal of Economic Policy
• /
• 제35권4호
• /
• pp.1-29
• /
• 2013

본 논문은 세계화가 우리나라 제조업 사업체의 성장과 양극화에 미친 영향을 살펴본 것이다. 본 논문은 먼저 이론적으로 세계화가 성장 및 양극화에 미치는 영향 및 그 구체적 메커니즘을 최근 이질적 기업의 무역이론들을 중심으로 논의하고, 나아가 관련 실증적 증거들이 존재하는지를 살펴보았다. 이를 통하여 본 논문은 세계화가 1990년대 이후 우리나라 제조업 사업체의 생산성 향상뿐 아니라 기업 간 생산성 및 숙련도별 임금 양극화 모두를 초래한 공통적 원인으로 작용하였음을 보여주었다. 본 연구는 최근 세계화된 경제환경하에서 왜 극소수의 대기업만이 특출한 성과를 나타내고 있는지를 이해하는 데 도움이 된다. 마지막으로 본 연구는 세계화의 부작용을 줄이고 그 편익을 보다 많은 기업들이 누릴 수 있도록 하기 위한 정책방향을 제시한다.

• 한국대기환경학회지
• /
• 제32권2호
• /
• pp.131-157
• /
• 2016

A smog chamber has been an effective tool to study air quality, particularly secondary organic aerosol (SOA), which is typically formed by atmospheric oxidation of volatile organic compounds (VOCs). In controlled environments, smog chamber studies have validated atmospheric oxidation by identifying, quantifying and monitoring products with state-of-art instruments (e.g., aerosol mass spectrometer, scanning mobility particle sizer) and provided chemical insights of SOA formation by elucidating reaction mechanisms. This paper reviews types of smog chambers and the current state of smog chamber studies that have accomplished to find pathways of SOA formation, focusing on gas-particle partitioning of semivolatile products of VOC oxidation, heterogeneous reactions on aerosol surface, and aqueous chemistry in aerosol waters (e.g., cloud/fog droplets and wet aerosols). For future chamber studies, then, this paper discusses potential formation pathways of fine particles that East Asia countries (e.g., Korea and China) currently suffer from due to massive formation that gives rise to fatal health problems.

• Design & Manufacturing
• /
• 제15권4호
• /
• pp.43-50
• /
• 2021

Pump-cap is a device for discharging the contents stored inside a container to the outside of the container by a simple operation by a certain amount. In particular, in recent years, as the number of cosmetic products made of functional materials has rapidly increased, the development of convenient containers for functional materials is being actively conducted. Among these, there are a growing number of products that show their efficacy only by mixing two components, so the development of a dual pump cap container is necessary. However, the conventional dual pump cap container has a problem in that it is difficult to implement a quantitative discharge as solutions having different viscosities are used. Therefore, in this study, a discharge port of a dual pump cap that can apply an optimal ratio was designed by analyzing the discharge amount of two components with different viscosities through computational fluid dynamics. Since the discharge amount is affected by the size of the discharge port, the higher the viscosity of the solution, the larger the discharge port should be set. Conversely, the lower the viscosity, the smaller the discharge port should be. Through this, it is possible to dispense a fixed amount of a heterogeneous solution by one pumping, and it is determined that the user's convenience will increase.

• 유통과학연구
• /
• 제11권4호
• /
• pp.61-72
• /
• 2013

Purpose - It is widely accepted that the process of developing marketing strategy is composed of three steps: market segmentation, target market selection and positioning. However, mass marketing strategy based on cost reduction through economies of scale and standardized products, can be also an effective strategic option. Many marketing scholars including Theodore Levitt emphasize the importance of applying the mass production concept to various industries including service industries. Especially, in times of economic downturn, the capability of providing consumers with low-priced, value products can be an important source of competitive advantage, as well as the ability of providing high-priced premium products. Marketers should decide whether they will implement mass marketing strategy or target marketing strategy. The present study theoretically shows that firms should understand the target customers' price elasticity as well as the firm's cost structure in order to make such a strategic decision. Research design, data, and methodology - Instead of implementing an empirical study, this study provides a theoretical(mathematical) investigation on the effect of consumers' price elasticity on a firm's optimal price level, profit, sales volume, revenue, and cost. The results are mostly deduced from derivative calculations and several graphs are utilized to represent the results on the relationships between the variables under study. Results - The analytical results suggest that it is more profitable for a firm to adopt the segment/target marketing strategy (more specifically the differentiation strategy) when the degree of consumers' heterogeneity is high and the proportion of the fixed cost in the total cost is low. On the other hand, if the degree of consumers' heterogeneity is low and the fixed cost is high, it is better to adopt the mass marketing strategy or the cost leadership strategy. The strategy of concentrating on a single target market will be effective when consumers' needs are highly heterogeneous but the fixed cost is high. Any of the three types of generic strategies proposed my Porter(1980, 1985) can be applied when both the consumers' heterogeneity and the fixed cost are low. This study also proposes the contribution-margin-based method for developing the optimal pricing strategy. Conclusions - One of the primary roles of marketers is to find a proper compromise between the two conflicting goals of maximizing customer satisfaction and minimizing cost. In order to do so, he or she should understand the characteristics of the target customers as well as the cost structure of the firm. In addition to the theoretical analyses, this study discusses several business cases and explains how superior companies find the optimal compromise position between these two goals and dominate the market. One of the radical changes recently taking place in business arena is the reduction of production and distribution costs of both physical goods and information due to the advancement and the wide diffusion of information technology. The cost reduction combined with lowered priced elasticity incurred by customized products and services, will enable many firms to adopt the mass customization strategy.

• 한국지진공학회논문집
• /
• 제11권4호
• /
• pp.25-31
• /
• 2007

For areas such as the Korean Peninsula, which have moderate seismic activity but no available records of strong ground motion, synthetic seismograms can be used to evaluate ground motion without waiting for a strong earthquake. Such seismograms represent the estimated ground motions expected from a set of possible earthquake scenarios. Local site effects are especially important in assessing the seismic hazard and possible ground motion scenarios for a specific fault. The earthquake source and rupture dynamics can be described as a two-step process of rupture initiation and front propagation controlled by a frictional sliding mechanism. The seismic wavefield propagates through heterogeneous geological media and finally undergoes near-surface modulations such as amplification or deamplification. This is a complex system in which various scales of physical phenomena are integrated. A unified approach incorporates multi-scale problems of dynamic rupture, radiated wave propagation, and site effects into an all-in-one model using a three-dimensional, fourth-order, staggered-grid, finite-difference method. The method explains strong ground motions as products of complex systems that can be modified according to a variety of fine-scale rupture scenarios and friction models. A series of such deterministic earthquake scenarios can shed light on the kind of damage that would result and where it would be located.

• 한국결정성장학회지
• /
• 제8권1호
• /
• pp.187-192
• /
• 1998

일반적으로 재료의 응고조직은 주상정과 등축정 수지상 영역으로 이루어지는데 이것은 제품의 기계적, 물리적 성질과 밀접한 관계를 가지기 때문에 주상정-등축정 천이에 관한 많은 이론적 연구가 행하여지고 있다. 본 연구에서는 J.D. Hunt에 의하여 일방향응고시 주상정앞에서의 핵생성과 결정성장조건을 이용하여 구하여진 해석학적 주상정-등축정 조건식을 바탕으로 응고속도에 따라 변하는 분배계수와 액상선기울기를 적용하여 수정된 조건식을 구하였다. 그리고 Al-Cu합금에 대하여 응고변수인 핵생성수, 핵생성온도, 합금의 조성, 응고속도 온도기울기에 따른 천이현상의 변화를 조사하였다.

• 한국가구학회지
• /
• 제24권2호
• /
• pp.140-147
• /
• 2013

In the latest furniture design field, we can find mass production with concept of heterogeneity that is made by harmonizing existing object with other object, which has new value. In order to follow the trend in the reality, various design process method that applied concept of Hybrid is attempted by flexibly combining or changing heterogeneous materials, formations or functions such as combination of new material and wood or IT. However, not like other design fields, its research range in furniture design is limited. This study is conducted in order to overcome and supplement problems that are made when these different materials are combined, such as faults or cracks made due to difference of expansion and contraction coefficient, lack of intensity and change of formation due to external temperature and humidity. Panels that are combined for this study were verified materials that have passed environmental adaptation test throughout the period of 1 year and 2 months, which will be made into a table. By doing this, this study will be an empirical study that establish concept of furniture made with acrylic and provides manufacturing method of combining wood and acrylic. Finally it proposed a new furniture design method that follows the trend by researching new materials with the new concept.