• 제목/요약/키워드: Mo/Si

검색결과 929건 처리시간 0.025초

Impacts of Soil Microbial Populations on Soil Chemical and Biological Properties under Tropical Dry Evergreen Forest, Coromandel Coast, India

  • Sudhakaran, M.;Ramamoorthy, D.;Swamynathan, B.;Ramya, J.
    • Journal of Forest and Environmental Science
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    • 제30권4호
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    • pp.370-377
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    • 2014
  • There are very few studies about soil chemical and biological properties under tropical dry evergreen forest Coromandel Coast, India. The present study was conducted in six tropical dry evergreen forests sites such as Oorani, Puthupet, Vadaagram, Kotthatai, Sendrakillai and Palvathunnan. We measured the quantity of soil chemical, biological properties and selected soil microorganisms for investigating the impacts of soil microbial populations on soil chemical and biological properties. The result showed that total N, P, Ca, S, Fe, Mn, Cu, Co, exchangeable K, Olson P, extractable Ca and phosphobacterial population were higher in the soil from Kothattai forest site. Organic carbon, total Mg, extractable Na, soil respiration, ${\beta}$-glucosidase activity, bacterial population, fungi population and actinomycetes population were higher in the soil from Palvathunn forest site. Total K, $NH_4{^+}$-N, $NO_3{^-}$-N, exchangeable K, extractable Ca, extractable Na, azotobacter population, bacillus population and rhizobacteria population were higher in the soil from Sendrakillai. Beijerinckia population, rhizobacteria and soluble sodium were higher in Puthupet forest soil. Total Si, total Na and exchangeable K were higher in soil from Oorani forest site. Total Mo and exchangeable K were higher in the soil from Vadaagaram forest site. The results showed that organic carbon, total N, $NH_4{^+}$-N, $NO_3{^-}$-N, extractable P, extractable Ca, soil respiration and ${\beta}$-glucosidase were significantly correlated with soil microbial populations. Therefore soil microorganisms are important factor for maintaining soil quality in tropical dry evergreen forest.

구강스캐너와 급속 지르코니아 소결을 이용한 당일 풀지르코니아 보철수복 (Digital workflow of single visit full contour monolithic zirconia restoration with CEREC Omnicam intraoral scanner and fast zirconia sintering process)

  • 이수영
    • 대한심미치과학회지
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    • 제25권2호
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    • pp.79-87
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    • 2016
  • 당일수복 보철물 제작을 위해 디지털 프로세스 사용은 필수적이다. 이러한 디지털 프로세스는 구강스캔, 컴퓨터를 이용한 보철물을 디자인 과정(CAD)과 보철물을 가공하는 과정(CAM)을 포함한다. 지르코니아의 굴곡강도는 900Mpa로 리튬디실리케이트의 400MPa보다 더 단단하지만, 리튬디실리케이트를 이용한 보철물 기공시간이 지르코니아와 비교하여 더 짧기에 당일수복 보철물 제작시 리튬디실리케이트 사용이 선호되었다. 하지만, TZI C 와 LUXEN Enamel 와 같은 새로운 소재의 지르코니아가 출시되고, 새로운 소결방식이 개발되어 지르코니아 기공시간을 단축시킬수 있게 되었고, 높은 투명도의 풀지르코니아 크라운을 짧은 시간 안에 제작할 수 있게 되었다. 이러한 발전은 당일 풀지르코니아 보철수복을 현실로 이끌고 있다.

A Materials Approach to Resistive Switching Memory Oxides

  • Hasan, M.;Dong, R.;Lee, D.S.;Seong, D.J.;Choi, H.J.;Pyun, M.B.;Hwang, H.
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제8권1호
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    • pp.66-79
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    • 2008
  • Several oxides have recently been reported to have resistance-switching characteristics for nonvolatile memory (NVM) applications. Both binary and ternary oxides demonstrated great potential as resistive-switching memory elements. However, the switching mechanisms have not yet been clearly understood, and the uniformity and reproducibility of devices have not been sufficient for gigabit-NVM applications. The primary requirements for oxides in memory applications are scalability, fast switching speed, good memory retention, a reasonable resistive window, and constant working voltage. In this paper, we discuss several materials that are resistive-switching elements and also focus on their switching mechanisms. We evaluated non-stoichiometric polycrystalline oxides ($Nb_2O_5$, and $ZrO_x$) and subsequently the resistive switching of $Cu_xO$ and heavily Cu-doped $MoO_x$ film for their compatibility with modem transistor-process cycles. Single-crystalline Nb-doped $SrTiO_3$ (NbSTO) was also investigated, and we found a Pt/single-crystal NbSTO Schottky junction had excellent memory characteristics. Epitaxial NbSTO film was grown on an Si substrate using conducting TiN as a buffer layer to introduce single-crystal NbSTO into the CMOS process and preserve its excellent electrical characteristics.

Implant에 사용되는 CAD/CAM 전용 zirconia abutment의 표면적과 디자인에 따른 유지력 차이 (Differences in retention of the reduction direction depending on dimensions and design CAD/CAM zirconia abutment for implant)

  • 남택모;김한곤;김병식;임시덕
    • 대한치과기공학회지
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    • 제32권4호
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    • pp.317-325
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    • 2010
  • Purpose: The aim of this study is to make some basic materials to find retention force difference based on the total height of CAD/CAM zirconia abutment used for implant, retention force difference based on how to regulate the height of the abutment, retention force difference based on the size and retention force difference based on the design group. Methods: The retention force was measured by being pulled at the speed of 1mm/min after being combined with zirconia block and abutment using Temp-BOND of Kerr. The experiment was done at the research lab of OSTEM in Busan by useing UNIVERSAL TESTING MACHINE on March 3rd, 2010. Results: After analysing the total height and the retention force, p-value had minor difference by 0.01 statistically. Namely, 3mm, 4mm, 5mm had the retention force difference and we could see retention force difference on 3mm and 5mm at the post test. After analyzing how to regulate the height and retention force, p-value had minor difference by 0.000 statistically. Namely, 1mm and 2mm had the retention difference and we could see that 1mm and 2mm with the total height had retention difference. After analyzing the retention force based on the size, p-value had minor retention force difference by 0.000 statistically. Namely, 7 different size had retention force difference and we could see the size 21.9mm, 32.9mm, 32.9mm, 38.4mm, 48.9mm and 54.9mm had retention force difference. Conclusion: Namely 9 different design group had retention difference and we could see that 9 design group with 5.6.7.8 design group and 9 design group with 1.2.3.4. design group had retention force.

돌발성 난청의 한방치료 치험례에 대한 고찰 (Review on Case Reports of Korean Medical Treatments for Sudden Sensory Neural Hearing Loss)

  • 이유리;김경순;최홍식;김승모
    • 동의생리병리학회지
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    • 제32권1호
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    • pp.62-69
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    • 2018
  • This study aimed to review case reports of Korean medical treatments for sudden sensory neural hearing loss published in Korea from 1980 to 2016. We searched sudden sensory neural hearing loss through 6 major Korean web article search engines and search period was January 1980 to September 2016. Two researchers included studies on sudden hearing loss, clinical studies on korean medical treatments, and excluded in vivo studies, in vitro studies, non-original studies, published abstracts only, and studies not published in Korean or English. 19 articles were included in this study from 63 articles. Only one case report used Korean medical treatment alone. The most tools for treatment were acupunture, herbal medicine, pharmacopunture, moxibustion, cupping treatment and laser therapy. Most acupoints used in the treatment is SI19(聽宮). When patients got treated sooner, recovery rate was better. There was no direct relationship between recovery rate and degree of hearing loss. This study suggests that more research about sudden sensory neural hearing loss is needed in the future.

도시철도 사상사고 유형·원인 분류 및 표준화 방안 (Classification and Standardized Coding for Urban Railway Casuality Accident Types and Causes)

  • 모천석;김시곤;권영종;강갑생
    • 대한토목학회논문집
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    • 제35권5호
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    • pp.1173-1177
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    • 2015
  • 본 논문에서는 도시철도역사 내 철도안전사상사고의 사고유형과 원인분류를 표준화하는 방안을 제시하였다. 이를 위하여 도시철도 운영기관 (서울메트로, 서울도시철도공사)의 4,086건 철도안전사상 사고를 분석하여 표준화 코드를 작성하였다. 사고유형의 표준화는 사상자유형, 사고대상, 사고 위치, 사고형태로 구분하여 분류하고 이를 포함한 4자리의 표준화코드를 제시하였다. 사고원인의 표준화는 원인제공자, 음주여부, 1차 원인, 2차 원인을 포함한 4자리의 표준화코드를 제시하였다. 이러한 표준화코드는 도시철도 역사 내 철도안전사상사고의 체계적인 비상관리 및 긴급대응에 기본이 되는 역할을 담당할 것이라 판단된다.

Blocking filter용 자심 재료의 전자기 특성 및 신호 감쇄율 (Electromagnetic Properties of Magnetic Core Materials and Attenuation of Blocking Filter)

  • 오영우;이해연;김현식
    • 한국전기전자재료학회논문지
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    • 제16권6호
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    • pp.490-495
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    • 2003
  • The electromagnetic properties and thermal behavior of Mn-Zn ferrite cores for the blocking filter of Power Line Communication(PLC) application were investigated as a function of additives. The highest density and permeability were 4.98 g/$\textrm{cm}^2$ and 8,221, respectively and were obtained to the specimen with composition of MnO 24 mol%, ZnO 25 mol% and Fe$_2$O$_3$ mol%, added MoO$_3$ of 400 ppm, SiO$_2$ of 100 ppm, and CaO of 200 ppm. The uniform grains were organized, and the microstructures were densified due to reduction of pores in the specimen. The permeability was increased up to 13,904 as the temperature of specimen increased to 110$^{\circ}C$. However, it was decreased precipitously under 100 over 110$^{\circ}C$. The exothermic behavior was observed in the frequency range from 1 kHz to 1 MHz, and the maximum temperature of specimen was 102$^{\circ}C$ at 1 MHz. In the consequence, the Mn-Zn ferrite core developed in this research will maintain the stable electromagnetic properties since the temperature of ferrite core rose to 93$^{\circ}C$ in the range of 100 kHz to 450 kHz bandwidth qualified for PLC. The blocking filters were designed for single phase and three phases using the in-line and non-contact core. The best attenuation ratios of -46.46 dB and -73.9 dB were measured in the range of 100 kHz to 450 kHz bandwidth, respectively.

한국산 灰重石鑛의 광물학적, 지화학적 연구 및 그의 探査에의 이용 (The Mineralogical and Geochemical Study on Korean Scheelites and its Application to the Ore Prospecting)

  • So, Chil-Sup;Park, Maeng-Eon
    • 자원환경지질
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    • 제12권2호
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    • pp.79-93
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    • 1979
  • 한반도 내에 부존되고 있는 중적광상들은 세 주요한 Metallousenetic Epoch (Pre-Cambrian E., Jurassic-early Cretaceous E., 및 late Cretaceous-early Tertiary E.)에 생성되었고 성인으로 열수작용과 접촉교대작용에 기인된다고 보고되었다. 이중 12개 광상(달성, 산내, 일광, 상동, 대화, 월악, 복수, 옥방, 쌍전, 홍성, 삼봉, 청양)을 본 연구의 대상으로 택하고 각 지역에서 채취한 표품중 모두 25개 시료에 대하여 지화학적 실험을 수행하였다. 즉 각 분쇄된 시료 (-80+120mesh)는 super panner, 중액, isodynamic separator, UV lamp를 이용한 물리적인 처리과정을 거쳐 최종으로 입체현미경 하에서 단체분리된 후 Jarrell-Ash 1.5m Grating Spectrometer를 이용하여 본 연구대상 시료로 개발한 Spectrochemical method (Carrier: NaCl, Internal standard: $La_2O_3$)로 정량 분석되었다. 본 연구에서 밝혀낸 국내 회중석 광내에 함유되는 희유 윈소의 종류는 모두 Al, Bi, Fe, Si, Mn, Pb, Mg, Sn, Mo, Cu, Sr, Cr, Y, Ag, Ti, Ni, As, Yb의 18개 원소이며, 이들은 각각의 절대적 및 상대적인 함량과 각 광화작용의 시기, 광상의 성인, 모암, 각 원소의 mobility 그리고 회중석광의 형광색 및 육안색과 비교 검토되었다. 본 연구의 결과로 회중석광이 정출되는 과정에서 유사한 지질환경의 물리화학적인 여건이 이루어지면 그 내에 함유되는 몇 성분원소들의 화학적인 특성은 매우 유사성을 보여주는 typochemical habit를 가짐을 알 수 있었다. 본 연구에서 밝혀진 한국산 회중석 광내의 희유성분(稀有成分)으로서 Y, Mn, Sr 원소들의 Geochemical mobility의 특성(特性)은 앞으로 회중석광의 심도탐광을 위하여 고려되어야하고, 더욱 연구개발되어야 할 것이다. 또한 상기 회중석 광내의 물리적 및 화학적으로 결합되어 있는 불순물의 희유성분들은 선광 제련 파정에서 금속성분의 추출농집공정(工程)에 유용한 자료가 될 것이다.

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Source Identification and Quantification of Coarse and Fine Particles by TTFA and PMF

  • Hwang, In-Jo;Bong, Choon-Keun;Lee, Tae-Jung;Kim, Dong-Sool
    • Journal of Korean Society for Atmospheric Environment
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    • 제18권E4호
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    • pp.203-213
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    • 2002
  • Receptor modeling is one of statistical methods to achieve reasonable air pollution strategies. In order to maintain and manage ambient air quality, it is necessary to identify sources and to apportion its sources for ambient particulate matters. The main purpose of the study was to survey seasonal trends of inorganic elements in the coarse and fine particles. Second, this study has attempted emission sources qualitatively by a receptor method, the PMF mo-del. After that. both PMF (positive matrix factorization) model and TTFA (target transformation factor analysis) model were applied to compare and to estimate mass contribution of coarse and fine particle sources at the receptor. A total of 138 sets of samples was collected from 1989 to 1996 by a low volume cascade impactor with 9 size fraction stages at Kyung Hee University in Korea. Sixteen chemical species (Si, Ca, Fe, K, Pb, Na, Zn, Mg, Ba, Ni, V, Mn, Cr, Br, Cu. Co) were characterized by XRF. The study result showed that the weighted arithmetic mean of coarse and fine particles were 51.3 and 54.4 $\mu\textrm{g}$/㎥, respectively. Contribution of both particle fractions were esti-mated using TTFA and PMF models. The number of estimated sources was seven according to TTFA model and 8 according to PMF model. Comparison of TTFA and PMF revealed that both methodologies exhibited similar trends in their contribution pattern. However, large differences between contributions were observed in some sour-ces. The results of this study may help to suggest control strategies in local countries where known source profiles do not exist.

기문비록(岐門秘錄)에 대한 고찰 (Study on the Confidential Document of A Distinguished Medical Family)

  • 김동민;최경석;신승열;안준모;금경수;이시형
    • 동의생리병리학회지
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    • 제22권5호
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    • pp.1078-1105
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    • 2008
  • An empirical formula that has been empirically shown to be effective for a particular condition can be said to add medicinal materials to an existing formula or to make a new prescription by the Korean medical doctors' empirical clinic. This dissertation aims to study the prescriptions according to A Confidential Document of A Distinguished Medical Family written by the writer's ancestor and to contribute to the development of Korean medicine. A Confidential Document of A Distinguished Medical Family is a medicinal recipe that is an heirloom of the Gyeongju Kim family for the eighth generation. And the date and the writer of the book are unknown. The contents of the book consist of 18 parts and are made up of about 300 medical recipes. Of these, 158 formulas and indications of cold damage, wind, urination, stool, jaundice, and internal injury are found in the book. From among these, 61 formulas was directly quoted out of The Precious Mirror of Oriental Medicine, 97 formulas are adjusted in proportion or combined. By the parity of reasoning of the above, I think that this book was published after The Precious Mirror of Oriental Medicine. I will continue to study other formulas except the formulas above mentioned.