• 통상정보연구
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• 제8권2호
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• pp.187-210
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• 2006

China continues to experience an expansion of its e-Commerce industry. This is true both for B2C and for B2B sectors. B2C websites are created by various players. B2C E-commerce is divided into three categories in China: online direct sale, online retail, and online booking services. Online retail remains the major form of B2C business, and online booking services and online direct sale also maintained rapid growth. The rapid growth of B2C E-commerce in China was due to three factors. Firstly, the number of Internet users is increasing, which expands E-commerce user base. Secondly, users' acceptance and recognition of E-commerce are gradually increasing. Lastly, improvement on payment, logistics and credit also provides a better and better industrial environment for B2C e-commerce. The B2C sector has seen a low transaction volume in spite of its large number of websites. The B2B sectors has seen a higher transaction volume and more stable growth than the B2C sector. There is a wide range of the total market size estimated by different sources. China's C2C market witnessed rapid growth in 2005, the market growth may slow down in 2006 and 2007, due to heavy market competition, challenges to the business model and slow corporate user growth. But there is the bottlenecks in E-commerce in China. The purpose of this paper is contribute to development E-commerce in China by finding the solutions of the bottlenecks in E-commerce in China.

• 상하수도학회지
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• 제21권3호
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• pp.359-366
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• 2007

Slow sand filtrations have been widely used for water treatment in small communities, however their capacity is often limited by high turbidity in the raw water. For this reason, several pre-treatment facilities were required for a slow sand filter. Turbidity removal from the highly turbid raw water was investigated in roughing filters as a pre-treatment process. The roughing filters followed by rapid mixing tank were operated in the form of a contact filtration. In several jar tests, the predetermined optimum aluminium sulfate (alum) doses for turbid water of 30 and 120NTU were 30 and 50mg/L, respectively. At the optimum alum dose, physically optimum parameters including G value of $220sec^{-1}$ and rapid mixing time of 3 minutes were applied to the contact filtration system. Without addition of alum, the filtrate turbidity from the roughing filters, packed respectively with different media such as sand, porous diatomite ball and gravel, was in the range of 5~30NTU at filtration velocities of 30 and 50m/day. However, the application of a contact filtration to roughing filters showed stably lower filtrate turbidity below 1.0NTU at filtration velocity of 30 m/day. Although the filtration velocity increased to 50m/day, filtrate turbidity was still below 1.0NTU in both single and double layer roughing filters. At influent turbidity of 120NTU, the filtrate turbidity was over 5 NTU in the triple layer roughing filter, which shortened the filter run time. The flocs larger than $10{\mu}m$, formed in the rapid mixing tank, were almost captured through the roughing filter bed, while the almost flocs smaller than $10{\mu}m$ remained in filtrate.

• 한국자동차공학회논문집
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• 제15권2호
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• pp.8-14
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• 2007

Compression ignition of homogeneous charges in IC engines indicates possibilities of achieving the high efficiency of DI diesel engines with low level of NOx and particulate emissions. The objectives of this study are to further understand the characteristics of the HCCI(Homogeneous charge compression ignition) combustion and to find ways of extending the rich HCCI operation limit in an engine-like environment. DME fuel is supplied either in the form of premixture with air or directly injected in the combustion chamber of a rapid compression and expansion machine under the conditions of various equivalence ratio and injection timing. The cylinder pressure is measured and the rate of heat release is computed from the measured pressure for the analysis of the combustion characteristics. The experimental data show that the RCEM can operate without knock on mixtures of higher equivalence ratio, when DME is directly injected in the combustion chamber than introduced as a fraction of a perfect or nearly perfect premixture. Very early fuel injection timings usually employed in HCCI operation are seen to have only insignificant effects in control of ignition timing.

• Journal of Dairy Science and Biotechnology
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• 제33권4호
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• pp.271-275
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• 2015

Colloidal semiconductor CdSe-ZnS core-shell nanocrystal quantum dot (Qdot) are luminescent inorganic fluorophores that show potential to overcome some of the functional limitations encountered with organic dyes in fluorescence labeling applications. Salmonella Enteritidis has emerged as a major cause of human salmonellosis worldwide since the 1980s. A rapid, specific, and sensitive method for the detection of Salmonella Enteritidis was developed using Qdot as a fluorescence marker coupled with immunomagnetic separation. Magnetic beads coated with anti-Salmonella Enteritidis antibodies were employed to selectively capture the target bacteria, and biotin-conjugated anti-Salmonella antibodies were added to form sandwich immune complexes. After magnetic separation, the immune complexes were labeled with Qdot via biotin-streptavidin conjugation, and fluorescence measurement was carried out using a fluorescence measurement system. The detection limit of the Qdot method was a Salmonella Enteritidis concentration of $10^3$ colony-forming units (CFU)/mL, whereas the conventional fluorescein isothiocyanate-based method required over $10^5CFU/mL$. The total detection time was within 2 h. In addition to the potential for general nanotechnology development, these results suggest a new rapid detection method of various pathogenic bacteria from a complex food matrix.

• 한국전자통신학회논문지
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• 제16권2호
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• pp.233-240
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• 2021

다양한 함량으로 네오디뮴이 도핑된 황화아연 박막제작은 RF 마그네트론 스퍼터링 장비를 이용하여 황화아연과 네오디뮴을 동시 증착하여 박막을 제작하였고, 후처리 공정으로 급속열처리를 400℃ 에서 30분간 실시하였다. 다양한 네오디뮴의 도핑 함량(0.35at.%, 1.31at.%, 1.82at.% 및 1.90at.%)을 갖는 ZnS 박막의 구조, 형태, 광학적 특성을 연구하였다. X-선 회절 패턴은 모든 박막에서 (111)방향의 큐빅 구조로 성장하였다. SEM 이미지와 AFM 이미지를 통해 네오디뮴 도핑 함량에 의한 박막의 표면 및 구조적 형태에 대하여 설명하였다. EDAX를 통해 다른 불순물이 포함되지 않은 Zn, S 및 Nd의 원소만을 확인하였다. UV-vis 스펙트럼을 이용하여 제작된 박막의 투과율과 밴드갭을 확인하였다.

• 한국ITS학회 논문지
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• 제20권3호
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• pp.20-33
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• 2021

현대 사회는 한정된 도로로 증가하는 교통 수요를 처리하기 위해 대중교통 장려 정책을 꾸준히 실시하고 있다. 버스의 경쟁력을 확보하기 위해 전국적으로 간선급행버스체계(BRT) 설치가 확대함에 따라 버스의 신속성 보장을 위한 우선 신호에 대한 기대가 높아지고 있다. 그러나 일부 버스 운영 측면을 고려하지 않은 BRT 정류장 형태는 버스의 정지횟수를 증가시켜 버스 우선 신호 적용 효과를 감소시킬 수 있다. 이에 본 연구는 세종시 한누리대로를 분석 대상지로 하여 BRT 정류장 형태에 따른 버스 우선 신호 효과를 분석함으로써 버스의 운영 효율을 높이기 위한 정류장 형태에 대해 제언하고자 한다. 버스 우선 신호는 일반 차량과 버스의 양방향 연동폭을 최대화하는 기법을 적용하였다. 적용 결과 버스의 이중 정차를 야기하는 정류장에서 버스 우선 신호의 효과가 급격히 감소하였으며 이를 개선 후 우선 신호의 효율이 상당히 증가하였다. 본 연구의 결과는 향후 신도시에 BRT 정류장 설계 시 교통운영 측면을 고려한 올바른 정류장 형태의 근거자료로써 활용이 가능할 것으로 기대된다.

• 한국실내디자인학회논문집
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• 제20권6호
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• pp.291-299
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• 2011

As our lifestyles have changed due to rapid industrialization and urbanization, new social and communication problems have been caused and there have been lots of discussion on regional communication. For communities to become alternatives with realistic meanings in this changed society, considerations on social and spatial conditions are needed. Therefore, public space which works as a device of physical environment for activation of communities needs more active changes which encourages social communication. In respect to the activation of communities, the following suggestions are given: First, physical devices of a urban plaza should be arranged to support various programs presented along with consideration of human behaviors as users. Second, fundamental facilities of the plaza should accommodate various activities through connections with programs and commercial space. Third, when cultural and historical characteristics of the community are understood, the plaza can form regionality and symbolism through artistic representation. And users can form the identity of community. Fourth, transportation facilities should be separated from or coexist with areas of passengers and the plaza should have its own identity through symbolic sculptures.

• 한국해양공학회지
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• 제33권6호
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• pp.535-546
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• 2019

The paper presents a closed-form analytical solution for the ultimate strength of sandwich panels with metal faces and an elastic isotropic core during combined in-plane compression and lateral pressure under clamped boundary condition. By using the principle of minimum potential energy, the stress distribution in the faces during uni-axial edge compression and constant lateral pressure was obtained. Then, the ultimate edge compression was derived on the basis that collapse occurs when yield has spread from the mid-length of the sides of the face plates to the center of the convex face plates. The results were validated by nonlinear finite element analysis. Because the solution is analytical and closed-form, it is rapid and efficient and is well-suited for use in practical structural design methods, including repetitive use in structural optimization. The solution applies for any elastic isotropic core material, but the application that stimulated this study was an elastomer-cored steel sandwich panel that had excellent energy absorbing and protective properties against fire, collisions, ballistic projectiles, and explosions.

• 대한가정학회지
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• 제11권3호
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• pp.314-328
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• 1973

Highly developed and Complicated modern society demands earlier development of a human intelligence. Thus the trend of ecucations nowadays has been rapid increase of efford in the field of child education. As a result experiments to find out the ways of developing child intelligence have been repeatedly carried out and various theories concerning them have been expressed. The aim of this study is to review such theories and researches. Generally, the ways how to develop child intelligence are divided into tow parts. One is by means of operating mental abilities of a child and the other is providing abundant environment to a child for the facilitation of such mental operation. A. Mental Operation The intelligence of a child is more likely to be developed by thorough and precise training of following four mental abilities. 1. Ability of classification 2. Ability of analogy 3. Ability of variation 4. Ability of inference B. Environment Child intelligence is also more likely to be developed by providing him next four environments. 1. When the parents maintaina moderate expectation and have know-ledge of the child's mental development. 2. When the parents follow the standard linguistic form and provide the child with ample opportunities for the verval expression. 3. When the parents provide tools and materials and opportunities for the cultural experiences. 4. When the parents furnish immediate rewards to the child's intellectual achievements and help him form a positive self-concept with regard to the intellectual abilities.

• 대한치과의사협회지
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• 제54권5호
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• pp.348-355
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• 2016

Ideal autogenous or allogenic bone graft materials should provide 1) stabilization of blood clot, 2) scaffolds for cellular proliferation and differentiation, 3) release of osteogenic growth factors, 4) appropriate resorption profile for remodeling of new bone. Teeth, especially dentin, mostly contain hydroxyapatite and type I collagen which are similar to bone, and could be valuable graft material. Clinically teeth are used as calcined or demineralized forms. Demineralized form of dentin can be more effective as a graft material. But a conventional decalcification method takes time and long treatment time may give negative effects to various osteogenic proteins in dentin. Author used a new clinical method to prepare autogenous teeth, which could be grafted into the removal defects immediately after extraction using vacuum ultrasonic system. The process could be finished within two hours regardless of the form (powder, chip or block). Teeth were processed to graft materials in block, chip, or powder types immediately after extraction. It took 120 minutes to prepare block types and 40 minutes to prepare powder. Clinical cases did not show any adverse response and the healing was favorable. Rapid preparation of autogenous teeth with the vacuum ultrasonic system could make the immediate one-day extraction and graft possible.