• International Journal of Knowledge Content Development & Technology
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• v.12 no.1
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• pp.35-47
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• 2022

This study adopted the descriptive survey research method. The population of this study comprised of the hearing impaired students in selected government secondary schools in Rivers state. The population of hearing impaired students in Rivers State is 257. A simple random sampling technique was used to select a sample size of 159. A self-developed instrument titled "Availability and Utilization of Library Information Resources Questionnaire (AULIRQ)" was utilized for data collection. 153 responses were collated, indicating a 96.2% response rate. The data collected was arranged and analyzed using frequency count, percentages, and mean and standard deviation. Finding reveals that information resources in the libraries understudied were inadequate and under-utilized. Also, it was established that among other barriers, under-funding is a major barrier to making information resources available for the physically challenged. It was recommended that schools offering special education for the hearing impaired should pace up in their developmental gap by providing such resources and ensure adequate funding by all stakeholders.

• Resources Recycling
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• v.27 no.6
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• pp.3-10
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• 2018

Tungsten is a metal with high melting point and used as a raw material for the production of super alloys. Tungsten exists as $WO{_4}^{2-}$ in alkaline solution. As solution pH decreases, polymerization reaction of $WO{_4}^{2-}$ occurs to result in the precipitation of tungstic acid. The hydrometallurgical process for the recovery of tungsten from ores or secondary resources can be classified as acid and alkaline leaching. In selecting a process for the recovery of pure tungsten from secondary resources, the nature and concentration of impurities in the secondary resources and the manufactured tungsten materials should be considered.

• The Journal of Korean Association of Computer Education
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• v.10 no.4
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• pp.103-112
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• 2007

This study purposed to analyze problems in utilizing hardware and software invested for elementary and secondary school that were distributed through the education information project so far, and to make plans for substantial operation. In order to identify relevant problems and to draw up plans for substantial operation, this study analyzed relevant previous researches and investigated the current state of the utilization of educational information resources in school through question investigation. In addition, we visited elementary, secondary schools, and governmental departments of relevant personnel and had interviews with the people there. From this, we suggested the substance proposals of the educational information resources operation for elementary and secondary school. Therefore, the substance proposal to the information resource in education that was produced by this study would be useful to establish and execute relevant policy for elementary and secondary schools and governmental departments.

• Journal of Advanced Navigation Technology
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• v.24 no.2
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• pp.121-127
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• 2020

In this paper, we propose a dynamic spectrum hole grouping method that changes the grouping range of spectrum hole according to the resources amount required by secondary users in wideband spectrum cognitive wireless networks, and then the proposed method is applied to channel allocation for the secondary user service. The proposed method can improve waste of resources in the existing static spectrum hole grouping in virtue of grouping dynamically as much the predicted spectrum holes resources as secondary users require. Simulation results show that channel allocation method with the proposed dynamic grouping outperforms that with the static grouping method in resources utilization under acceptable secondary user service performance.

• Particle and aerosol research
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• v.15 no.4
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• pp.127-137
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• 2019

Recently, high electrochemical performance anode materials for lithium ion secondary batteries are of interest. Here, we present silicon-carbon-graphene (Si-C-GR) composites for high performance anode materials of lithium ion secondary battery (LIB). Aerosol process and heat-treatment were employed to prepare the Si-C-GR composites using a colloidal mixture of silicon, glucose, and graphene oxide precursor. The effects of the size of the silicon particles in Si-C-GR composites on the material properties including the morphology and crystal structure were investigated. Silicon particles ranged from 50 nm to 1 ㎛ in average diameter were employed while concentration of silicon, graphene oxide and glucose was fixed in the aerosol precursor. Morphology of as-fabricated Si-C-GR composites was generally the shape of a crumpled paper ball and the Si particles were well wrapped in carbon and graphene. The size range of composites was about from 2.2 to 2.9 ㎛. The composites including silicon particles larger than 200 nm in size exhibited higher performance as LIB anodes such as capacity and coulombic efficiency than silicon particles less than 100 nm, which were about 1500 mAh/g at 100 cycles in capacity and 99% in coulombic efficiency, respectively.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.105-105
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• 2022

Unripen mandarin in Jeju Island is known to contain functional ingredients including various flavonoids. This Study was carried out to identify the components of Unripen mandarin extracts and Secondary metabolism by enzyme treatment on Unripen mandarin. We extracted Unripen mandarin using optimal extraction method and selected the most optimal enzyme among commercial enzymes for a Secondary metabolism. As a result, flavonoid components such as Hesperidine and Narirutin, which are known to be contained a lot in unripen mandarin, could be analyzed. However In this extraction method there were no other flavonoid components such as Nobiletin, Tangeretin known to contain in unripen mandarin. However as a result of secondary metabolism a new functional component called Prunin which was not known to be contained in unripen mandarin, was detected as a secondary metabolic product due to enzyme treatment. Through this, it can be confirmed that it would be possible to develop high-value-added products by enzyme treatment on unripen mandarin.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.3-8
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• 2001

The mineral industry of the United States is going through a challenging time. The US as an industrial nation faces with increasing demand in raw materials to fuel various industrial sectors but, at the same time, meeting environmental constraints associated with excavating and extracting these raw materials. In addition, gradual depletion of material resources. and the necessity of handling more complex forms of resources of primary origin have led to a decline in her resource productivity, once a strategic advantage of the U.S. As a result. the United States currently relies heavily upon foreign importation of various materials such as precious and strategic metals. However, since the US is the major consumer of most of these materials, the recovery of these values from scrap would help renew her position as a resource-producing nation, and ultimately help spur its domestic economy. Furthermore. recycling would also help maintain a clean environment and reduce energy consumption. In this paper. the author attempts to discuss opportunities and challenges lied ahead of the US mineral in relation to recovering their much-needed resources from secondary sources. The need and demand in various metals in the US will be reviewed and discussed. The implication of resource recovery from secondary sources will also be discussed. Extraction methods treating secondary sources are inherently different from those for primary sources. There is a need for new technologies which are metallurgically efficient and environmentally benign in treating secondary sources. Ways to meet such a need will be examined and key factors to be considered in approaching these challenges will be discussed.

• Resources Recycling
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• v.22 no.2
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• pp.3-10
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• 2013

Indium is one of the rare metals, and it has been used mainly for preparation of indium tin oxide (ITO). This review investigated the process parameters and the merits and demerits of several methods to recover indium from the leaching solution of secondary resources, such as solvent extraction, ion exchange, and precipitation. D2EHPA has been used mostly as a cationic extractant for indium extraction in moderate acid solutions, while amine extractants are used in strong hydrochloric acid solution. Since the loading capacity of resins for indium is generally small, ion exchange has some advantage over solvent extraction only when the concentration of indium is low.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.23-23
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• 2018

Taiwan, formerly known as Formosa, located on tropical and subtropical climate zones with abundant biological resources. According to the latest version of the Flora of Taiwan, there are 4339 species of vascular plants including 1054 endemic species. First, Taiwania (Taiwania cryptomerioides), named after its native island of Taiwan, have been isolated more than 500 secondary metabolites, including lignans, terpenoids, steroids, and flavonoids. Several of the metabolites are reported to have antibacterial, antifungal, antimite, antitermite and antitumor activities. In order to investigate plant secondary metabolic diversity toward industrial applications, we established deep transcriptome resources for non-model plants and fungi to produce terpenoid metabolites of economic importance. Second, many plants of Lauraceae have been utilized in folk medicine for their exciting bioactivities. The twigs and leaves from 27 tree species of Lauraceae grown in Taiwan were performed to evaluate potential bioactivity. The leaves of Cinnamomum osmophloeum are traditionally used in folk medicines, and many biological activities have been identified, such as antibacterial, antifungal, antitermite, antidiabetic, antihyperuricemia, antiinflammatory, and antioxidant activities. However, C. osmophloeum has nine chemotypes with various secondary metabolite profiles. In order to efficiently produce active compounds, we established the genetic markers to identify the chemotype plants. Finally, Cinnamomum kanehirae is the host of the medicinal mushroom Antrodia cinnamomea. Several in vivo and in vitro studies indicated that A. cinnamomea possesses a diverse range of biological activities. Because of the potential pharmacological application, we established the transformation system to enhance the triterpenoid contents production.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.381-385
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• 2004

본 인구에서는 레이놀즈응력모형을 이용하여 직사각형 개수로 흐름을 수치모의 하고 이차흐름의 생성 메커니즘을 제시하였다. 수치모의 결과 자유수면과 측벽의 접합부 근처에서 inner secondary flow가 발생하였다. 이는 최근 Grega 등(1995)과 Hsu 등(2000)에 의해 밝혀진 새로운 이차흐름이다. 또한 측벽에서의 전단력 분포를 계산한 결과 inner secondary flow에 의하여 수면 근처에서의 전단력 값이 증가하는 것으로 나타났다. 계산된 결과를 이용하여 와도 방정식에서 각 항의 크기를 비교하여 이차 흐름의 생성 메커니즘을 살펴보았다. 그 결과 벽 및 측벽 경계 부근에서는 난류의 비등방성에 의한 와도 생성항에 의해 이차 흐름이 생성되고, 경계와 멀리 떨어진 영역에서는 레이놀즈응력에 의한 와도 생성항이 이차흐름을 생성시키는데 중요한 역할을 하는 것으로 나타났다.