• 제목/요약/키워드: Heary metal

검색결과 4건 처리시간 0.017초

Evaluation of the accuracy of mobile cone-beam computed tomography after spinal instrumentation surgery

  • Eom, Ki Seong;Park, Eun Sung;Kim, Dae Won;Park, Jong Tae;Yoon, Kwon-Ha
    • Journal of Trauma and Injury
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    • 제35권1호
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    • pp.12-18
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    • 2022
  • Purpose: Pedicle screw fixation provides 3-column stabilization, multidimensional control, and a higher rate of interbody fusion. Although computed tomography (CT) is recommended for the postoperative assessment of pedicle screw fixation, its use is limited due to the radiation exposure dose. The purpose of this preliminary retrospective study was to assess the clinical usefulness of low-dose mobile cone-beam CT (CBCT) for the postoperative evaluation of pedicle screw fixation. Methods: The author retrospectively reviewed postoperative mobile CBCT images of 15 patients who underwent posterior pedicle screw fixation for spinal disease from November 2019 to April 2020. Pedicle screw placement was assessed for breaches of the bony structures. The breaches were graded based on the Heary classification. Results: The patients included 11 men and four women, and their mean age was 66±12 years. Of the 122 pedicle screws, 34 (27.9%) were inserted in the thoracic segment (from T7 to T12), 82 (67.2%) in the lumbar segment (from L1 to L5), and six (4.9%) in the first sacral segment. Although there were metal-related artifacts, the image of the screw position (according to Heary classification) after surgery could be assessed using mobile CBCT at all levels (T7-S1). Conclusions: Mobile CBCT was accurate in determining the location and integrity of the pedicle screw and identifying the surrounding bony structures. In the postoperative setting, mobile CBCT can be used as a primary modality for assessing the accuracy of pedicle screw fixation and detecting postoperative complications.

Nucleation and Growth of Diamond in High Pressure

  • Choi, Jun-Youp;Park, Jong-Ku;Kang, Suk-Joong L.;Kwang, Yong-Eun
    • The Korean Journal of Ceramics
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    • 제2권4호
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    • pp.221-225
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    • 1996
  • In diamond synthesis by metal film growth method under high pressure and high temperature, the nucleation and growth of diamond was observed dependent on the carbon source variation from graphite powder to the heat treated powders of lamp black carbon. At the low driving force condition near equilibrium pressure and temperature line, nucleation of diamond did not occur but growth of seed diamond appeared in the synthesis from lamp black carbon while both nucleation and growth of diamond took place in the synthesis from graphite. Growth morphology change of diamond occurred from cubo-octahedron to octahedron in the synthesis from graphite but very irregular growth of seed diamond occurred in the synthesis from lamp block carbon. Lamp black carbon transformed to recrystallized graphite first and very nucleation of diamond was observed on the recrystallized graphite surface. Growth morphology of diamond on the recrystallized graphite was clear cubo-octahedron even at higher pressure departure condition from equilibrium pressure and temperature line.

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폐패각을 이용한 수처리에 관한 연구 (A Study on the Water Treatment using Shell Waste)

  • 이민호;정태섭
    • 자원리싸이클링
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    • 제6권3호
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    • pp.28-35
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    • 1997
  • 조개껍질(굴, 고막)을 수처리재로 활용하기 위한 기초 실험으로 중금속(Cd, Cu, Fe, Mn, Pb, Zn)과 유기성분(TCE(Trichlo-roethylene)와 PCE(Tetrachroethylene))의 흡착능을 조사했다. 수산화칼슘으로 이루어진 굴과 고막껍질의 소성 분말 주입에 따른 중금속 제거효율은 Mn, Zn, Fe, Cd, Cu, Pb의 순이었다. 우수한 중금속 흡착능은 조개껍질의 $Ca(OH)_2$ 성분에 의한 높은 pH유지에 따른 중금속 탄산염과 수산화물의 형성에 의한 침전작용, 조개껍질의 칼슘 매트릭스 구조에 의한 중금속의 고정화와 잔존하는 불용성 유기물의 결합 등의 작용이라고 본다. 이와 같은 굴껍질은 침출수의 중화작용과 동시에 우수한 중금속 흡착능을 가지고 있어, 이것을 수처리로 활용될 경우, 저렴한 재료의 확보와 더욱이 부가가치가 높은 폐부산자원을 활용한 정화용 세라믹스 담체의 개발로 폐부산자원 폐기처리 문제 이외의 환경정화용 세라믹스 및 담체 등의 환경분야 사업으로 확장 발전시킬 수 있다고 본다.

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공주제일광산 수계에 분포하는 지하수, 지표수, 토양 및 퇴적물의 환경지구화학적 특성과 중금속 오염 (Environmental Geochemistry and Heavy Matel Contamination of Ground and Surface Water, Soil and Sediment at the Kongjujuil Mine Creek, Korea)

  • 이찬희
    • 자원환경지질
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    • 제32권6호
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    • pp.611-631
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    • 1999
  • Enviromental geochemisty and heary metal contamination at the Kongjueil mine creek were underaken on the basis of physicohemical properties and mineralogy for various kinds of water (surface, mine and ground water),soil, precipitate and sediment collected of April and December in 1998. Hydrgeochemical composition of the water samples are characterized by relatively significant enricant of Ca+Na, alkiali ions $NO_3$ and Cl inground and surfore water, wheras the mine waters are relatively eneripheral water of the mining creek have the characteristics of the (Ca+Mg)-$(HCO_3+SO_4)$type. The pH of the mine water is high acidity (3.24)and high EC (613$\mu$S/cm)compared with those of surface and ground water. The range of $\delta$D and $\delta^{18}O$ values (relative to SMOW) in the waters are shpwn in -50.2 to -61.6% and -7.0 to -8.6$\textperthousand$(d value=5.8 to 8.7). Using computer program, saturation index of albite, calcite, dolomite in mine water are nearly saturated. The gibbiste, kaolinite and smectite are superaturated in the surface and ground water, respectively. Calculated water-mineral reaction and stabilities suggest that weathing of silicate minerals may be stable kaolinite owing to the continuous water-rock reaction. Geochemical modeling showed that mostly toxic heavy metals may exist larfely in the from of metal-sulfate $(MSO_4\;^2)$and free metal $(M^{2+})$ in nmine water. These metals in the ground and surface water could be formed of $CO_3$ and OH complex ions. The average enrichment indices of water samples are 2.72 of the groundwater, 2.26 of the surface water and 14.15 of the acid mine water, normalizing by surface water composition at the non-mining creek, repectively. Characteristics of some major, minor and rate earth elements (Al/Na, K/Na, V/Ni, Cr/V, Ni/Co, La/Ce, Th/Yb, $La_N/Yb_N$, Co/Th, La/Sc and Sc/Th) in soil and sediment are revealed a narrow range and homogeneous compositions may be explained by acidic to intermediate igneous rocks. And these suggested that sediment source of host granitic gneiss colud be due to rocks of high grade metamorphism originated by sedimentary rocks. Maximum concentrations of environmentally toxic elements in sediment and soil are Fe=53.80 wt.% As=660, Cd=4, Cr=175, Cu=158, Mn=1010, Pb=2933, Sb=4 and Zn=3740 ppm, and extremely high concentrations are found are found in the subsurface soil near the ore dump and precipitates. Normalizing by composition of host granitic gneiss, the average enerichment indices are 3.72 of the sediments, 3.48 of the soils, 10.40 of the precipitates of acid mine drainage and 6.25 of the soils near the main adit. The level of enerichment was very severe in mining drainage sediments, while it was not so great in the soils. mineral composition of soil and sediment near the mining area were partly variable being composed of quartz, mica, feldspar, chlorite, vermiculite, bethierin and clay minerals. reddish variable being composed of quartz, mica, feldspar, chlorite, vermiculite, bethierin and clay minerals. Reddish brown precipitation mineral in the acid mine drainage identifies by schwertmanite. From the separated mineralgy, soil and sediment are composed of some pyrite, arsenopyite, chalcopyrite, sphalerite, galena, malachite, goethite and various kinds of hydroxied minerals.

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