• Asian Journal of Atmospheric Environment
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• 제2권2호
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• pp.102-108
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• 2008

In China, energy and environmental problems are becoming serious owing to rapid economic development. Coal is the most problematic energy source because it causes indoor and outdoor air pollution, acid rain, and global warming. One type of clean coal technology that has been developed is the coal-biomass briquette (or bio-briquette, BB) technique. BBs, which are produced from pulverized coal, biomass (typically, agricultural waste), and a sulfur fixation agent (slaked lime, $Ca(OH)_2$) under high pressure without any binder, have a high sulfur-fixation effect. In addition, BB combustion ash, that is, the waste material, can be used as a neutralization agent for acidic soil because of its high alkalinity, which originates from the added slaked lime. In this study, we evaluated the suitability of alternative biomass sources, namely, aquatic plants, as a BB constituent from the perspective of their use as a source of energy. We selected three types of aquatic plants for use in BB preparation and compared the fuel, handling, and environmental characteristics of the new BBs with those of conventional BBs. Our results showed that air-dried aquatic plants had a higher calorific value, which was in proportion to their carbon content, than agricultural waste biomass; the compressive strength of the new BBs, which depends on the lignin content of the biomass, was high enough to bear long-range intracontinental transport in China; and the new BBs had the same emission control capacity as the conventional BBs.

• 한국식품과학회지
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• 제30권6호
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• pp.1321-1326
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• 1998

박피마늘 제조과정 중 폐기되는 마늘 뿌리부위의 이용을 위해 oleoresin의 제조 및 저장 조건을 검토하였다. 여러 가지 용매를 사용하여 $30{\sim}50^{\circ}C$에서 추출하였을 때 ethanol과 methanol이 $27{\sim}37%$의 높은 고형분 수율을 보여주었고 추출시간은 2시간이 적절하였다. 진공 또는 질소충진 조건에서 저장하였을 때 공기존재하에서 저장한 것보다 pH와 총산도, 색, thiosulfinate의 변화가 현저히 적었다. Thiosulfinate의 함량은 저장중 모든 저장조건에서 감소함을 보였다. 질소충진하에서 저장 중 glucose와 sucrose 함량은 증가하였으며 유기산은 감소하였다. Oleoresin에 ascorbic acid와 cysteine의 첨가는 저장 중 마늘향기를 보존하는데 유익하였다.

• Strategy21
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• 통권44호
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• pp.28-53
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• 2018

The U.S. has recently developed Free and Open Indo-Pacific strategy and Distributed Lethality strategy based on a common perception that they are responding to China's threats. In the future, it is anticipated the following. Strengthen cooperation of the U.S.-India-Vietnam navy, Maximizing the combined combat power between the U.S. and regional navies, Improving its ability to restore damage control, Economic cooperation between the Pacific and Indian countries. The meanings given to the Korean navy are as follows. First, South Korea should pursue cooperation with the Indian Navy, which will grow into a regional balance on China's growth. The growth of the Indian navy is expected to increase cooperation with other Pacific countries. The government should seek ways to promote cooperation with india navy in various fields. Secondly, it is a joint drill between the U.S. Navy and the Korean Navy. Recently, the Korea-U.S. joint drill has not been conducted and many changes are expected to be made regarding the implementation of the joint drill in the future. Therefore, it is necessary to respond to possible changes in the naval relationship between Korea navy and the U.S. navy Also, due to distributed lethality strategy, preparations for operations and training with U.S.navy will be necessary. Lastly, it should contribute to cooperation among regional countries in preparation for maritime territorial disputes. The growth of the Chinese navy and the territorial disputes in the East and South China sea has raised the possibility of accidental military clashes at sea. Therefore, the government should make efforts to create multilateral security cooperation systems that can continue to promote the prevention of armed conflict.

• Journal of Biosystems Engineering
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• 제41권4호
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• pp.294-303
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• 2016

Purpose: This study aimed to evaluate the profitability of four selective mechanization systems in rice cultivation. Methods: Field experiments were conducted in the farmers' field during the wet season (June to November) of 2015 in Bangladesh. Mechanization systems were applied to evaluate four different selective levels (treatment) in eleven consequent operations. Seedlings were raised in a traditional seedbed and trays for manual and mechanical transplanting, respectively. Land preparation, irrigation, fertilizer, pesticide, carrying, and threshing and cleaning operations were performed using the same method in all the experimental plots. The mechanical options in the transplanting, weeding, and harvesting operations were changed. The mechanization systems were $S_1$ = hand transplanting + hand weeding + harvesting by sickle, $S_2$ = mechanical transplanting + Bangladesh Rice Research Institute (BRRI) weeder + reaper, $S_3$ = mechanical transplanting + BRRI power weeder + reaper, and $S_4$ = mechanical transplanting + herbicide + reaper. This experiment was performed in a randomized complete block design with four replications. Power tiller, rice transplanter, BRRI weeder, BRRI power weeder, self-propelled reaper, BRRI open drum thresher, and BRRI winnower were used in the respective operations. Accordingly, the techno-economic performances of the different technologies were calculated and compared with those of the traditional system. Results: The mechanically transplanted plot produced 6-10% more yield than the hand transplanted plot because of the use of tender-aged seedlings. Mechanical transplanting reduced 61% labor and 18% cost compared to manual transplanting. The BRRI weeder, BRRI power weeder, and herbicide application reduced 74, 91, and 98% labor, respectively. The latter also saved 72, 63, and 82% cost, respectively, compared to hand weeding. Herbicide application reduced the substantial amount of labor and cost in the weeding operation. Mechanical harvesting also saved 96% labor and 72% cost compared to the traditional method of harvesting using sickle. Selective mechanization saved 15-17% input cost compared to the traditional method of rice cultivation. Conclusions: Mechanical transplanting with the safe use of herbicide and harvesting by reaper is the most cost- and labor-saving operation. The method might be the recommended set of selective mechanization for enhancing productivity.

• 한국재료학회지
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• 제24권5호
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• pp.255-258
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• 2014

Zirconium boride is an artificial or which is rarely found in the nature. $ZrB_2$ is popular in the hard material industry because it has a high melting point, excellent mechanical properties and chemical stability. There are two known methods to synthesize $ZrB_2$. The first involves direct reaction between Zr and B, and the second is by reduction of the metal halogen. However, these two methods are known to be unsuitable for mass production. SHS(Self-propagating High-temperature Synthesis) is an efficient and economic method for synthesizing hard materials because it uses exothermic reactions. In this study, $ZrB_2$ was successfully synthesized by subjecting $ZrO_2$, Mg and $B_2O_3$ to SHS. Because of the high combustion temperature and rapid combustion, in conjunction with the stoichiometric ratio of $ZrO_2$, Mg and $B_2O_3$; single phase $ZrB_2$ was not synthesized. In order to solve the temperature problem, Mg and NaCl additives were investigated as diluents. From the experiments it was found that both diluents effectively stabilized the reaction and combustion regime. The final product, made under optimum conditions, was single-phase $ZrB_2$ of $0.1-0.9{\mu}m$ particle size.

• 산업경영시스템학회지
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• 제44권3호
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• pp.39-49
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• 2021

The Korean Air-Force aircraft maintenance depot paints the exterior of various aircraft, including high-tech fighters. Aircraft exterior painting is a maintenance process for long-term life management by preventing damage to the aircraft surface due to corrosion. The de-painting process is essential to ensure the quality of aircraft exterior paints. However, because the Korean Air-Force's de-painting process is currently done with sanding or Plastic Media Blasting (PMB) method, it is exposed to harmful dust and harmful compounds and consumes a lot of manpower. This study compares the de-painting process currently applied by the ROK Air-Force and the more improved process of the US Air Force, and performs economic analysis for the introduction of advanced equipment. It aims to provide information that can determine the optimal time to introduce new facilities through Cost-Volume-Profit (CVP) analysis. As a result of the analysis, it was confirmed that the sanding method had the most economical efficiency up to 2 units per year, the PMB method from 3 to 21 units, and the laser method from 22 units or more. In addition, in a situation where the amount of de-painting work is expected to increase significantly due to the increase in fighters in future, BEP analysis was conducted on the expansion of the existing PMB method and the introduction of a new laser method. As a result of the analysis, it was confirmed that it is more economical to introduce the laser method when the amount of work exceeds the PMB work capacity(18 units per year). The paper would helpful to improve the productivity and quality of the Korean Air Force Aircraft maintenance depot through timely changes of facilities in the workplace in preparation for expansion.

• 한국IT서비스학회지
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• 제20권6호
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• pp.45-62
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• 2021

After the COVID-19 outbreak in 2019, the spread of COVID-19 has not been easily caught despite preventive measures in each country. The spread of COVID-19 has hit the world, especially in the economic and tourism sectors. Countries around the world are easing restrictions on the movement of vaccinated people in preparation for the post-corona era. Under the name of "Vaccine Passport," "Vaccination Certificate," and "Digital Health Pass," vaccination measures are being implemented to allow vaccination recipients to use multi-use facilities. However, there is no international agreement on the movement of countries, and each country has its own immigration policy. In order to return to pre-corona daily life, global agreements must be reached from the movement of vaccinated people between countries, and standards and implementation methods must be determined. This study focuses on the implementation and utilization of vaccination certificates suitable for the COVID-19 era. We will look at the spread of COVID-19 and its international response policies. In the case of COVID-19, we will investigate why vaccination certificate installation should be standardized and how far the current standardization has been discussed, and discuss the characteristics of vaccination certificate installation and considerations. In order for the immunization certificate discussed in the previous chapter to be recognized internationally, institutional and technical considerations are identified and security factors that may occur in each implementation are also presented. Finally, the international recognition case of vaccination certificate is discussed, and the method of installation and utilization of vaccination certificate is proposed. This paper can be used as a policy because of its timeliness in studying the standards of vaccination certificates and considerations for international recognition to restore movement between countries in the spread of COVID-19. In addition, if other infectious diseases occur in the future or similar cases where movement between countries is restricted, it can be used as a reference to support the movement of verified people.

• Nano
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• 제13권10호
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• pp.1850113.1-1850113.11
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• 2018

Environmental and energy issues have always been a hot topic of global research. Oil leakage has caused great damage to the environment, affecting a wide area and it is difficult to clean up. In most cases, carbon-based adsorbents are typically utilized to remove oil spills because of their economic benefits and high adsorbent efficiency. At the same time, its excellent material properties can also be used for the preparation of supercapacitors. In this paper, the carbon aerogels were prepared by the one-step method. The prepared materials endowed a 3D network structure with a huge number of micropores and mesoporous, and the material is light-weight, stable, hydrophobic and has affinity for oil (17.02 g/g) to the KGM carbon aerogel. Through the physicchemical characterization, the KGM carbon aerogel shows specific surface area is $689m^2/g$, high water contact angle ($136.64^{\circ}$) and excellent reusability (more than 15 cycle times). In addition, we also discussed the electrochemical properties of the material and obtained the specific electrical capacity of 139 F/g under the condition of 1 A/g.

• 디지털산업정보학회논문지
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• 제15권1호
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• pp.133-155
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• 2019

The economic growth has made our lives more prosperous than the past, and the development of science fueled the era of 100-year lifespan. It is now distinct to us that preparation for life after retirement is not a choice but an imperative. In the meantime, outplacement programs have driven many to challenge and start a new chapter in life. This paper measures the characteristics of outplacement programs based on the self-determination factors; empirically examines how those characteristics influence on learning performance through self-efficacy and psychological well-being; concludes by proposing effective and productive ways for young adults and senior employees who are in search for new jobs. To test the research hypothesis, a survey was conducted among job searchers who have been previously provided with outplacement programs. The results are as follows: First, self-perceived autonomy has significant influences on self-efficacy and psychological well-being. Second, self-perceived competency has significant influences on self-efficacy and psychological well-being. Third, perceived relationship has no significant influence on self-efficacy and psychological well-being. Fourth, self-efficacy showed significant influences on psychological well-being, while not showing on learning performance. Fifth, psychological well-being has no significant influence on learning performance. This paper finds its academic significance in its theory-based approach to outplacement service program; research variables and examination are not based on researcher's arbitrary choice. This paper is also practically significant in that it discovered that outplacement service alleviates psychological stress caused by job relocation, and guarantees stable life after retirement.

• 한국융합학회논문지
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• 제10권4호
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• pp.107-113
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• 2019

1인가구의 가장 높은 비율을 차지하는 연령층은 60대 이상의 노인이다. 그들의 상당수가 경제적으로 어려운 상황에 처해있어 낙후된 주거공간에 거주한다. 노인의 주거공간의 창문은 존재하지 않거나 창문으로써의 역할을 제대로 하지 못하는 경우가 많다. 그들은 우울증, 고독사 등 사회적 문제에 취약한 상태로 노출되어 있다. 그래서 비상상황에 대한 대처능력이 현저히 떨어진다. 본 논문은 낙후된 주거공간에 거주하는 1인가구 중 60대 이상 노인을 대상으로 하는 외부 환경 정보 반영 대화형 창문 인터페이스를 제안한다. 본 콘텐츠는 별도의 공간과 비용이 요구되지 않는 보급형 TV 혹은 PC 모니터를 활용한다. 노인이 사용하는데 어려움이 없는 직관적인 터치센싱을 통해 손을 인식하면 현재 외부 환경을 반영하는 날씨 영상, 온도 정보를 제공한다. 보다 중요한 노인의 비상상황에 대비하여 알림소리, SMS전송 서비스를 제공한다. 본 콘텐츠를 통해 사용자는 정서적 안정을 느낄 수 있고 비상상황에 빠르게 대처할 수 있다.