• Applied Chemistry for Engineering
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• v.26 no.6
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• pp.714-718
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• 2015

Both lead molybdate ($PbMoO_4$) and chromium substituted lead molybdate ($PbMo_{1-x}Cr_xO_4$) were successfully synthesized using a conventional hydrothermal method and characterized by XRD, DRS, Raman, SEM and PL. We also investigated the photocatalytic activity of these materials for the decomposition of rhodamine B under UV-visible irradiation. The XRD and Raman results revealed the successful synthesis of well-crystallized $PbMoO_4$ crystals with the diameter of 51-59 nm, regardless of the addition of chromium ion. The DRS spectra of $PbMo_{1-x}Cr_xO_4$ catalysts showed new intensive absorption bands in the visible region. The $PbMoO_4$ catalysts showed the lowest photocatalytic activity and the activity increased with an increase of chromium substitution amounts under visible irradiation. PL peaks appeared at about 540-580 nm for all catalysts and excitonic PL signals were proportional to the photocatalytic activity for the decomposition of rhodamine B.

• Radiation Oncology Journal
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• v.11 no.2
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• pp.449-454
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• 1993

The skin sparing effect associated with high energy x-ray or gamma ray beams may be reduce or lost under certain conditions of treatment. Current trends in using large fields. Shield carrying trays, compensating filters, and isocentric methods of treatment have posed problems of increased skin dose which sometimes become a limiting factor in giving adquate tumor doses. We used the shallow ion chamber to measure the phantom surface dose and the physical treatment variables for Co-60 gamma ray, 4MV and 10 MV x-ray beam. The dependence of percent surface dose on field sizes, atomic number of the shielding tray materials and its distance from the surface for 4, 10MV x-rays and Co-60 gamma ray is qualitatively similar. The use of 2 mm thick tin filter is recommended for situations where a low atomic number tray is introduced into the beam at distances less than 15 cm from the surface and with the large field sized for 4 MV x-ray beam. In case of Co-60 gamma ray, the lead glass tray is suitable for enhancement of skin sparing. Also, the filter distance should be as large as possible to achieve substantial skin sparing.

• Korean Journal of Heritage: History & Science
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• v.46 no.1
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• pp.176-187
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• 2013

A study has been carried out on metal materials in order to identify the quantitative relation between the concentration and damage characteristics after evaluation of the damage characteristics according to the $SO_2$ concentration. The prepared metal samples, which were categorized according to the material (silver, copper, iron, lead, brass) were exposed to 0.01, 0.12, 1, 10, 100, 1,000, and 5,000ppm of $SO_2$ for 24 hours and the optical, physical, chemical deterioration rates both before and after testing were evaluated. The results showed optical deterioration, a loss of gloss on silver specimen with $SO_2$ 100ppm, an increase of color difference on brass, iron, copper and lead specimens with $SO_2$ 5,000ppm, as well as physical changes such as an increase of thickness and corrosion rate on iron sample with $SO_2$ 5,000ppm. In the case of chemical changes such as an increase sulfate ion ($SO{_4}^{2-}$) concentration and decrease of pH on iron and brass specimens were identified. These results suggest that $SO_2$ 100ppm caused clear optical deterioration on some metals such as silver and physicochemical and optical deterioration were identified at $SO_2$ 5,000ppm regardless of metal type. Also, It was concluded that iron and brass are the most susceptible of the metal specimens to $SO_2$.

• Journal of the Korean Electrochemical Society
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• v.17 no.2
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• pp.79-85
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• 2014

Silicon (Si) has been investigated as promising negative-electrode (anode) materials because its theoretical specific capacity of 4200 mAh/g for $Li_{4.4}Si$ is far higher than that of carbonaceous anodes in current commercial products. However, in practice, the application of Si to Li-ion batteries is still quite challenging because Si suffers from severe volume expansion and contraction and lead to a continuous solid electrolyte interphase (SEI)-filming process by cracking of Si. This process consumes the limited $Li^+$ source, builds up thick and unstable SEI layer on the Si active materials, and will eventually disable the cell. Since unstable SEI reduces electrochemical performance and thermal stability of the Si anode, the surface chemistry of the anode should be modified by using a functional additive. It is found that lithium bis(oxalato)borate (LiBOB) as an additive effectively protected the Si anode surface, improved capacity retention when stored at $60^{\circ}C$, and alleviated exothermic thermal reactions of fully lithiated Si anode.

• Journal of the Korean Chemical Society
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• v.44 no.2
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• pp.115-119
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• 2000

A PVC membrane electrode based on upper-rim calix[4] crown as ionophore was prepared using dioctyl sebacate (DOS) as a plasticizer. The potential response of this membrane electrode to alkali, alka-line earth and transitionmetal metal cations were examined. This membrane electrode exhibited a Nernstian response to $10^{-6}{\sim}10^{-2}M\;Pb(NO_3)_2$ with a slope ot 27.0 mV/decade. Its response time ($t_{90}$) was 10s and it could be used for at least 2 months. Also, the potential was maintained constantly in the rage of ph $2.0{\sim}12$.

• Resources Recycling
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• v.16 no.3 s.77
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• pp.50-60
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• 2007

There are several kinds of battery such as zinc-air battery, lithium battery, Manganese dry battery, silver oxide battery, mercury battery, sodium-sulphur battery, lead battery, nickel-hydrogen secondary battery, nickel-cadmium battery, lithium ion battery, alkaline battery, etc. These days it has been widely studied for the recycling technologies of the used battery from view points of economy and efficiency. In this paper, patents on the recycling technologies of the used lithium battery were analyzed. The range of search was limited in the open patents of USA(US), European Union(EP), Japan(JP), and Korea(KR) from 1986 to 2006. Patents were collected using key-words searching and filtered by filtering criteria. The trends of the patents was analyzed by the years, countries, companies, and technologies.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.393-398
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• 2005

Suspended fine mineral particles are deposited at the areas with low flow velocity and low transportation capacity in rivers, reservoirs and lakes. It can be contaminated by heavy metals. Examples of problem fields art dredging of sediment, water pollutants, and maintenance of navigation channels and construction works. To deal with the settling problems it is necessary to understand tile physico-chemical characteristics of cohesive sediment under varying density of particle and ion addition(NaOH, HCl, NaCl), which is dissolved in river, because fine-grained cohesive sediment can lead to flocculation with the physico-chemical influences and takes different characteristics. Experiments with fresh and saline water are followed with fine-grained sediments(alumina and quartz) in settling columns. Settling velocity of suspended fine particles in still water was measured with a pressure sensor(maximum 10 mbar). Until the initial concentration of 20,000 mg/1 of alumina and quartz the settling velocity was on the increase. Above this initial concentration was it on the decrease. In an acid condition, which causes strong flocculation, average settling velocity of quartz powder was high. In an alkaline water low average settling velocity of it was observed. However, alumina behaved exactly contrarily.

• Resources Recycling
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• v.17 no.2
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• pp.76-84
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• 2008

There are several kinds of battery such as zinc-air battery, lithium battery, manganese dry battery, silver oxide battery, mercury battery, sodium-sulphur battery, lead battery, nickel-hydrogen secondary battery, nickel-cadmium battery, lithium ion battery and alkaline battery, etc. These days it has been widely studied for the recycling technologies of the used battery from view points of economy and efficiency. In this paper, patents on the recycling technologies of the used manganese dry battery were analyzed. The range of search was limited in the open patents of USA (US), European Union (EP), Japan (JP), and Korea (KR) from 1986 to 2006. Patents were collected using key-words searching and filtered by filtering criteria. The trends of the patents were analyzed by the years, countries, companies, and technologies.

• Resources Recycling
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• v.21 no.4
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• pp.16-25
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• 2012

There are several kinds of batteries such as zinc-air battery, lithium battery, Manganese dry battery, silver oxide battery, sodium-sulphur battery, lead acid battery, metal hydride secondary battery, nickel-cadmium battery, lithium ion battery, alkaline battery, etc. These days it has been widely studied for the recycling technologies of the used battery from view points of economy and efficiency. In this paper, patents and published papers on the recycling technologies of the used battery were analyzed. The range of search was limited in the open patents of USA (US), European Union (EU), Japan (JP), Korea (KR) and SCI journal articles from 1972 to 2011. Patents and journal articles were collected using key-words searching and filtered by filtering criteria. The trends of the patents and journal articles were analyzed by the years, countries, companies, and technologies.

• Journal of the Korean Society for information Management
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• v.14 no.1
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• pp.125-159
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• 1997

The purpose of the research was to investigate the organizational integration process of the university library, computer center and other informa ion related operations. The research process follows : first, the literature review of the organizational integration of the information related operations. second, analysis of the organizational integration in Korea. third, the organizational integration of information related operation in US and Japan, then the case analysis of information related organizational integrations in Korea. This process lead us to point out few problems and pitfalls that could occur in the integration procedure. The total integration procedure has turned out to be the most effective in the University environment. And for the management of fully integrated organization. Vice-President and Chief Information Officer, - who is reponsible to suggest vision, leadership and ability to cope with the complex nature of the future information society - was strongly suggested.