• Resources Recycling
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• v.28 no.6
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• pp.26-35
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• 2019

This study aims to introduce and economical review on the possibilities of rare earth elements(REEs) recovery from coal ashes and the analysis of economical evaluation factors based on the data for securing domestic rare earth elements. The cut-off grade of REEs on recovering from coal ash was confirmed to be 1,000 ppm on total rare earth oxides(TREO) basis, and while the economic value of coal ash changed with contents and specific elements of rare earth elements. This shall be resulted in the price differences of rare earth elements required by the current industry, and it probably varies depending on the future demand of rare earth components. For developing of commercial recovery technology on REEs in coal ashes, many researches have been carried out by various analyzing methods, such as evaluation of holding value of REEs in ashes, assessment between supply and demand of industry, comparison of investment and its profitability for the REEs's production from coal ashes, and so on. Although these methods have been suggested, its recovery system with economical feasibility could not been confirmed up to present. In this reason, the process design of recovering REEs from coal ash shall be researched continuously to solve the problems of the global rare earth market. And also these researches shall be conducted actively in Korea for the purpose of securing the REEs resources and their recovering technologies.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.2
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• pp.60-67
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• 2015

The finite element (FE) model updating is a commonly used approach in civil engineering, enabling damage detection, design verification, and load capacity identification. In the FE model updating, acceleration responses are generally employed to determine modal properties of a structure, which are subsequently used to update the initial FE model. While the acceleration-based model updating has been successful in finding better approximations of the physical systems including material and sectional properties, the boundary conditions have been considered yet to be difficult to accurately estimate as the acceleration responses only correspond to translational degree-of-freedoms (DOF). Recent advancement in the sensor technology has enabled low-cost, high-precision gyroscopes that can be adopted in the FE model updating to provide angular information of a structure. This study proposes a FE model updating strategy based on data fusion of acceleration and angular velocity. The usage of both acceleration and angular velocity gives richer information than the sole use of acceleration, allowing the enhanced performance particularly in determining the boundary conditions. A numerical simulation on a simply supported beam is presented to demonstrate the proposed FE model updating approach.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.10 no.2
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• pp.27-42
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• 2015

The aim of this research is to investigate the difference in the capturing opportunities for each type of venture companies in the industry undergoing competition of a dominant design and then figure out the reason why they can be successful. Existing studies on venture companies are focused on the way to enhance a firm's competencies by acquiring and combining its resources. However, it is important for startups which have a lack of resources and capabilities to capture the opportunity to survive by understanding a changing environment. This study is focused on opportunity capture and strategic response to a changing environment and attempts to select and observe startup companies which are able to capture the opportunity and enter the market in the industry undergoing dominant design competition. In order to find out its difference in different types of business, we select one case from hardware startups and the other from software startups. According to the result of this study, the hardware startup focuses on market extension by lowering their prices and the software startup strives to induce more users to participate by the universalization of enabling technology so as to extend and standardize their technology in the environment undergoing dominant design competition. This feature of environment leads the difference in the approach for successfully capturing opportunity and thus hardware firms need to recognize the opportunity with profit potential from relationship with a number of cooperative firms while software firms need to identify the opportunity for extension of enabling technology which can be used by many users.

• Journal of Environmental Health Sciences
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• v.43 no.1
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• pp.64-70
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• 2017

Objectives: The purpose of this study is to examine the effect of the raise of cigarette prices by KRW 2,000 at the beginning of 2015 on the change in smoking behavior among male office workers, and to analyze the correlation of various factors including their work behaviors and socio-economic factors with their smoking rate. Methods: In this research, a follow-up observation panel was constituted with 420 smokers as targets from among male office workers at a bank located in Daegu, South Korea. A cross-analysis and ANOVA analysis were carried out in order to examine whether changes in smoking status, amount of smoking, stop-smoking motivation, and reasons for smoking cessation failure after the passage of time since the cigarette price hike were statistically significant. The level of statistical significance was P < 0.05. Results: After the cigarette price hike, among the 420 smokers who were the target of the panel the rate of smoking cessation declined at the time-point of the survey to 15.5%, 12.4%, 8.5%, and 5.7% after one month, three months, six months, and 12 months, respectively. As a result of a follow-up observation of 65 smokers who stopped smoking immediately after the price hike, the actual non-smoking rate declined to 15.5%, 8.3%, 4.4%, and 3.1% after one month, three months, six months, and 12 months, respectively. One (1) year after the cigarette price hike, the non-smoking rate among the 420 smokers reached as low as 3.1% (13 persons). The most important reason for the failure of the attempts to quit smoking was stress for more than 60% of the smokers who attempted to stop. Conclusions: It seems that a powerful anti-smoking policy by the state targeting the nation's workers is necessary. For companies, mediation for workers' job stress can become a strategy for the success of non-smoking attempts. The government seems to require a practical policy to reduce the smoking rate by actively carrying out social, economic, and scientific research to come up with a reduction method for the cigarette hazard, an effective price hike policy, and other non-price policies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.1-8
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• 2016

Current sensors are used widely in the fields of current control, monitoring, and measuring. They have become more popular with the increasing demand for smart grids in a power network, generation of renewable energy, electric cars, and hybrid cars. Although open loop Hall effect current sensors have merits, such as low cost, small size, and weight, they have low accuracy. This paper describes the design and fabrication of a 300A open loop current sensor that has high accuracy and temperature performance. The core of the current sensor was calculated numerically and the signal conditioning circuits were designed using circuit analysis software. The characteristics of the manufactured open loop current sensor of 300 A class was measured at currents up to 300 A. According to the test of the current sensor, the accuracy error and linearity error were 0.75% and 0.19%, respectively. When the temperature compensation was carried out with the relevant circuit, the temperature coefficients were less than $0.012%/^{\circ}C$ at temperatures between $-25^{\circ}C$ and $85^{\circ}C$.

• Journal of the Korean GEO-environmental Society
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• v.15 no.12
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• pp.35-42
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• 2014

The efforts to reduce carbon emission have been made in many aspects and in road, the study to develop the construction method which will replace asphalt and cement is also underway. But given the low cost and high performance offered by cement, among many solidification agents, it's difficult to seek the competent alternative. Polymeric material has been used in various ways for its advantages including lightweight and easy process for complex function and generates less carbon emission, and thus it would possibly be efficient if it replaces soil pavement using cement. This study, using three different types of organic polymeric solidification agents with different solidification principle, is intended to identify the difference in strength depending on curing method, natural dry or oven dry. Applicability of organic polymeric solidification agents to walkway and bike lane was investigated and as a result of unconfined strength test, all of them satisfied the minimum strength requirements of bike lane. Furthermore, strength characteristics of soil pavement depending on variation of water content was evaluated to identify the relationship, thereby appropriate curing method using organic polymeric solidification agent is proposed.

• KSBB Journal
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• v.23 no.5
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• pp.413-418
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• 2008

The production of 1,3.propanediol (1,3-PD) was investigated with Klebsiella pneumoniae DSM2026 and K. pneumoniae DSM4799 using crude glycerol obtained from biodiesel industry. Crude glycerol was used without prior purification to investigate effects of impurities in crude glycerol on 1,3-PD production. In the batch cultures, 1,3-PD production with crude glycerol was $1.1{\sim}2.5$ times higher than that with pure glycerol, indicating that crude glycerol is even a better substrate than pure glycerol for 1,3-PD fermentation. When glucose was added, 1,3-PD production and yield decreased in spite of enhanced cell growth. Furthermore, the addition of glucose was found to increase 2,3-butanediol, a by-product, significantly because of the change in metabolism in the presence of glucose. In semi-batch cultures without glucose addition, 26 g/L 1,3-PD was produced with crude glycerol, which was $2{\sim}3$ times higher than that with pure glycerol. Based on our results, it was clearly shown that crude glycerol is an effective substrate for biological 1,3-PD production, making it more feasible to produce 1,3-PD at a lower price.

• Composites Research
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• v.24 no.4
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• pp.23-28
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• 2011

Recently CFRP laminate joints process by bolts and nets are developed rapidly in aircraft industries. However, there are serious drawback during jointing process. Many hole processes are needed for the manufacturing and structural applications using composite materials. Generally, very durable polycrystalline crystalline diamond (PCD) drill has been used for the CFRP hole process. However, due to the expensive price and slow process speed, chemical vapor deposition (CVD) diamond drill has been used increasingly which are relatively-low durability but easily-adjustable process speed via drill shape change and price is much lower. In this study, the comparison of hole process between PCD and CVD diamond coated drills was done. First of all, CFRP hole processbility was evaluated using the equations of hole processing conditions (feed amount per blade, feed speed). The comparison on thermal damage occurring from the CFRP specimen was also studied during drilling process. Empirical equation was made from the temperature photo profile being taken during hole process by infrared thermal camera. In addition, hole processability was compared by checking hole inside condition upon chip exhausting state for two drills. Generally, although the PCD can exhibit better hole processability, hole processing speed of CVD diamond drill exhibited faster than PCD case.

• Journal of Science Education
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• v.36 no.2
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• pp.313-328
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• 2012

This study was conducted for the purpose of making the better utilization of MBL in class, based on 2009 curriculum which emphasizes research activities and recommends the direct use of the MBL. We investigated primary, secondary and pre-service teachers' satisfaction and perception level after conducting training about making good use of MBL. The satisfaction level of the training turned out to be high, level of applicability of MBL, expected improvement in learning skills of students and the will to apply it in class was high. The answer that they expect MBL to increase students' curiosity and interest in science was the highest among the survey results, which means that MBL could be used as a solution to lack of students' interest in science. Besides, primary teachers than secondary and pre-teachers, long careered teachers than short careered teachers and MBL-experienced teachers than inexperienced teachers showed more satisfaction and the will to adapt MBL overall. Primary and pre-teachers hoped MBL training to be more related to STEAM education, whereas secondary teachers wanted the training to have more to do with increasing creativity If advanced MBL training program is opened. The price was chosen as the best obstacle to MBL class' application, and the lack of manual for experiment and education to teacher was also pointed out secondly. In conclusion, if MBL is fully equipped in school and training on how to take advantage of it is provided continually, It is expected that MBL could increase the utilization in the field of science education. The results of this paper can be used when you configure the MBL utilization training program.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.9
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• pp.1583-1592
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• 2001

연구의 목적은 병행수입제도의 정책운용적인 관점에서 고가품 수입의 큰 비중을 차지 하고있는 럭셔리의류 브랜드를 중심으로 병행수입제도 도입 이후 현 시점에서 공정경쟁의 관점에서 병행수입의 문제점 추출과 대안을 도출함으로써 정책적 시사점을 제시하고자 한다. 연구 방법은 문헌조사와 in-depth 인터뷰를 실시하였다. 연구 결과 제도적 측면에서는 병행수입제도 도입 당시 병행수입과 직접 관련된 지적재산법과 독점규제법 사이에는 전용사용권자의 보호와 규제라는 입법적 목적이 서로 다른 이유로 병행수입 도입 여부에 대한 논란이 있는 것으로 나타났다 , 상표권 침해 기준의 모호, 세관절차에 있어서의 문제점 등이 추출되었다. 럭셔리의류 산업적 측면에서 병행수입제도는 수입물품의 가격인하를 선도하여 소비자 이익 증진에 기 여 하는 반면에 명품의 유통경로가 다양해짐에 따라 위조상품의 처벌실적 이 증가하고, 이월상품과overrun된 제품의 저가수입 등의 문제점이 야기되고 있다. 이에 대한 정책적 해결방안으로는 공정거래법의 개정을 통한 병행수입 허용기준의 보완, 지적재산권법 에 병행수입허용 규정 명시 , 소비자 관점에서의 병행수입 제품에 대한 정확한 정보의 전달 등의 내용 보완이 이루어져 야 한다. 본 연구의 시사점은 정책당국에게 경쟁조건의 Global Standard라는 견지에서 제도적 운용의 개선이 시급히 이루어져야 하는 논거와 토대를 제공하였다. 또한 전용사용권자와 병행수입업체에는 정보의 비대칭성에 의존한 판매전략을 지양하고 소비자 보호와 적 정 한 상표권 보호의 합리적 조화가 궁극적으로 생존의 핵심전략임을 인식시켜 줄 수 있는 계기를 마련해 주었다.가치관은 이들의 의복관심과 의복착용 그리고 구매에 지대한 영향을 미친다는 것을 알 수 있다.포제로 평가되었다. 모든 남자포제가 전통적, 순수한 이미지의 포제로, 철릭을 제외한 모든 포제가 단순한 이미지로 나타나 조선시대 남자 포제가 공통적으로 가지는 이미지는 단순하고 순수한 이미지를 가지고 있음을 알 수 있다. 3. 남자 포제의 시기별 복식이미지에서는 조선전기(철릭, 답호, 직령)의 포제는 관할성 요인이 높은 의례적인, 관할한, 특이한 이미지로 평가되었고 조선중기(도포, 창의)의 포제는 품위있는, 절제된, 풍성한 이미지로 평가되었으며, 조선후기(주의)의 포제는 활동적인, 단순한, 직선적인 이미지로 나타났다. 따라서 시대별 남자 포제의 이미지는 시대적 여건과 상황에 따라 변화되어 왔으며, 시대에 따라 추구하는 이미지가 달랐다는 것을 알 수 있이러한 논란의 해결방안으로 관세법 고시에 의한 우회적 도입을 결정한 정부의 방침에 대해 제도적 측면에서의 문제점으로 저작권 침해 기준의 결여다.lavonoid 함량의 판단지표로 활용될 수 있을 것으로 사료되었다.