• Title/Summary/Keyword: 장기 안정성

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Heavy Metal Stabilization in Soils using Waste Resources - A Critical Review (폐자원을 이용한 중금속 오염토양의 안정화 - 총설)

  • Lim, Jung Eun;Moon, Deok Hyun;Kim, Kwon-Rae;Yang, Jae E;Lee, Sang Soo;Ok, Yong Sik
    • Journal of Applied Biological Chemistry
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    • v.58 no.2
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    • pp.157-174
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    • 2015
  • Stabilization of metals in contaminated soils using various waste materials has been reported. Alkaline materials (limes, shells, industrial byproducts, etc.), phosphorous (P) containing materials (animal bones, phosphate rock, etc.), organic materials (composts, manures, biochars, etc.) and others (zerovalent iron, zeolite, etc.) were widely evaluated to ensure its effectiveness/applicability of stabilization of metals in soils. Stabilization mechanisms of those materials above were partially revealed, but the related literatures are still lacked and not sufficient for approaching to long-term stability/applicability in the field. The aims of this review are to summarize current knowledge of metal stabilization in contaminated soils using various waste materials and to suggest a direction for future field research.

Treatment of retrograde peri-implantitis: seven-year follow-up study (역행성 임플란트 근단병소 주위염(Retrograde Peri-implantitis) 치료의 7년 관찰)

  • Lee, Ju-Youn
    • Journal of Dental Rehabilitation and Applied Science
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    • v.30 no.3
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    • pp.259-264
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    • 2014
  • Retrograde peri-implantitis (RPI) is defined as a clinically symptomatic periapical lesion. RPI is generally accompanied by symptoms of pain, tenderness, swelling and fistula. Several etiologic factors of RPI were possible, residual bacteria would be the main cause of RPI. Various treatment modalities have been introduced: debridement only or a combination of debridement with the grafting material accompanied by a detoxification of the infected implant surfaces, apicoectomy and so on. Although the definitive management methods remain undefined, many favorable clinical results of a treatment of RPI have been published. This case report introduces the 7-year long-term clinical result of the application the principle: implant surface detoxification using saline and chlorhexidine and guided bone regeneration with bone graft material and barrier membrane. If the implant was not mobile, it would be possible to treat RPI according to surgical approach and good results will be maintained over long term.

Full mouth rehabilitation of a patient using monolithic zirconia and dental CAD/CAM system: a case report (단일구조 수복용 지르코니아와 Dental CAD/CAM System을 이용한 전악 임플란트 고정성 보철 수복 증례)

  • Lee, Sang-Hoon;Yoon, Hyung-In;Yeo, In-Sung;Han, Jung-Suk;Kim, Sung-Hun
    • Journal of Dental Rehabilitation and Applied Science
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    • v.34 no.3
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    • pp.196-207
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    • 2018
  • An accurate implant placement with ideal location is significant for long-term success of the implant. An exact evaluation of nearby anatomic structures such as quality of residual bone, an inferior alveolar bone and a maxillary sinus is required. For a prosthetic-driven treatment, planned surgery, precise prosthesis and communication with the patient are significant requisites especially for full-mouth rehabilitation. In this case, the patient with severe alveolar bone resorption had a CT guided surgery supported by CT data and the data from scanning diagnostic wax-up. Afterward, edentulous area was restored by full mouth implant-supported prosthesis by using monolithic zirconia and CAD/CAM technique. This paper reports the outcome of the procedure which was remarkable both esthetically and functionally.

Applicability of AE for the Prediction of Rock Slope Failure (암반비탈면 붕괴시 예측가능한 AE의 적용성에 관한 연구)

  • Lee, Dong-Keun;Kim, Yeon-Joong;Kim, Seok-Chun;Chun, Byung-Sik
    • Journal of the Korean Geotechnical Society
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    • v.27 no.1
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    • pp.25-34
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    • 2011
  • In general, many instrumentations of slope rely on theory or experience because on-site accessibility and long term instrumentation are difficult to conduct the instrumentation of slopes. Also the prediction of disaster is very difficult. Therefore experimental research was conducted about an effective method to predict collapse of slope and on-site applicability in this study. The collapse of slope was able to be predicted by applying AE sensor which we call WEAD to the failure criteria. The parameters of AE generated during the collapse of slope were secured through bending shear test. Test construction was applied to the slope with a history and a possibility of collapse. As a result, it is shown that AE parameters do not exceed the failure criterion and is found to be stable slopes. As the real symptoms of collapse did not appear, AE was found to have excellent applicability.

Research on the Surface Improvement of High Soft Ground Using Calibration Chamber Test (모형토조실험에 의한 초연약지반의 표층개량에 관한 연구)

  • Bang, Seongtaek;Yeon, Yongheum
    • Journal of the Korean GEO-environmental Society
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    • v.20 no.5
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    • pp.39-46
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    • 2019
  • Most of the soil used for reclamation is marine clay generated from dredging construction.The soft ground made of dredged clay has high water content and high compressibility, so the bearing capacity of the ground is very weak and it is difficult to enter the ground improvement equipment. Therefore, surface hardening treatment method is used to enter equipment prior to full-scale civil engineering work, and stabilizer is mainly used for cement series. Cement-based stabilizers have the advantage of improving the ground in a short period of time and have excellent economic efficiency, but they are disadvantageous in that they cause environmental problems due to leaching of heavy metals such as hexavalent chromium. In this study, environmental effects evaluation of dredged clay mixed with normal portland cement and environmentally friendly stabilizer was evaluated, and uniaxial compressive strength test and indoor model test were conducted to confirm the bearing capacity characteristics of the solidified layer.

Acute Oral Toxicity Study of Ethanol Extract of Curcuma longa L. in Mice (마우스에서 울금 에탄올 추출물의 단회 경구투여 독성에 관한 연구)

  • Kim, Soo-Hwan;Lee, Hyeong-Seon
    • Journal of Life Science
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    • v.24 no.10
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    • pp.1132-1136
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    • 2014
  • A yellow-colored pigment is found in turmeric, or Curcuma longa L. (Zingiberaceae), a perennial herb distributed mainly throughout tropical and subtropical regions. C. longa has potent antiviral, antimutagenic, anti-inflammatory, anticancer, and antioxidant properties. However, pharmacological mechanisms of ethanol extract derived from C. longa remain poorly understood. The aim of this study was to investigate the potential acute toxicity of C. longa (Curcuma longa L.) extract in BALB/c mice administered a single oral dose of 0, 20, 200, and 2,000 mg/kg by gavage. After the administration of the agent, signs of toxicity were observed every hour for the first 6 hr and every day for 14 days. No mortality, abnormal clinical signs, or pathological changes were observed compared to a control group, and there were no differences in the body weights of the control and treatment groups. Biological serum activities were not significantly changed in the treatment group compared to the control group. These results indicate that a single oral administration of C. longa extract does not exert any toxic effects at a dose of 2,000 mg/kg body weight and that the $LD_{50}$ of C. longa extract is greater than 2,000 mg/kg body weight. Accordingly, C. longa appears to have potential in various functional agents or foods, without toxicity.

Ecological Studies on the Warm-Season Turfgrass and Cool-Season Turfgrass Mixtures (난지형 잔디와 한지형 잔디의 혼식에 관한 생태학적 연구)

  • Park, Bong-Ju
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.6 no.5
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    • pp.21-27
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    • 2003
  • Five warm-season turfgrass [Zoysia japonica Steud., Stenotaphrum secundatum (Walt.) Kuntze, Buchloe dactyloides (Nutt.) Engelm., Eremochloa ophiuroides (Munro.) Hack. and Cynodon dactylon (L.) Pers.] were overseeded with 2 cool-season turfgrasses [Poa pratensis L. and Festuca arundinacea Schreb.] to examine suitability of these species for planting in mixture for producing a year-round turf. Percent of warm-season and cool-season turfgrasses in the mixture were estimated for 5 years. Also, to evaluate the fertilization times of the warm-season and cool-season turrfgras mixtures. Eremochloa ophiuroides and Buchloe dactyloides were not suitable for warm-season and cool-season turfgrass mixtures. However, Zoysia japonica, Stenotaphrum secundatum and Cynodon dactylon were suitable for warm-season and cool-season turfgrass mixtures. Zoysia japonica, Stenotaphrum secundatum and Cynodon dactylon were showed approximately 50% botanical composition five years after cool-season turfgrass overseeding. And, those three warm-season turfgrass mixtures showed approximately 20% visual ratings in winter period. Fertilization in early spring and late autumn had made cool-season turfgrass dominated in mixtures. Therefore, fertilization times in warm-season and cool-season turfgrass mixtures was desirable in summer period.

Influence of Implant Fixture-Abutment Connection and Abutment Design on Mechanical Strength (임플란트 고정체-지대주 연결부 및 지대주 디자인이 기계적 강도에 미치는 영향)

  • Chun, Mi-Hyun;Jeong, Chang-Mo;Jeon, Young-Chan;Eom, Tae-Gwan;Yoon, Ji-Hoon
    • Journal of Dental Rehabilitation and Applied Science
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    • v.24 no.3
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    • pp.269-281
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    • 2008
  • Fatigue or overload can result in mechanical problems of implant components. The mechanical strength in the implant system is dependent on several factors, such as screw and fixture diameters, material, and design of the fixture-abutment connection and abutment. In these factors, the last rules the strength and stability of the fixture-abutment assembly. There have been some previous reports on the mechanical strength of the fixture-abutment assembly with the compressive bending test or short-term cyclic loading test. However, it is restrictive to predict the long-term stability of the implant system with them. The purpose of this study was to evaluate the influence of the design of the fixture-abutment connection and abutment on the mechanical strength and failure mode by conducting the endurance limit test as well as the compressive bending strength test. Tests were performed according to a specified test(ISO/FDIS 14801) in 4 fixture-abutment assemblies of the Osstem implant system: an external butt joint with Cemented abutment (group BJT), an external butt joint with Safe abutment (group BJS), an internal conical joint with Solid abutment (group CJO), and an internal conical joint with ComOcta abutment (group CJT). The following conclusions were drawn within the limitation of this study. Compressive bending strengths were decreased in order of group BJS(1392.0N), group CJO(1261.8N), group BJT(1153.2N), and group CJT(1110.2N). There were no significant differences in compressive bending strengths between group BJT and group CJT(P>.05). Endurance limits were decreased in order of group CJO(600N), group CJT(453N), group BJS(360N), and group BJT(300N). 3. Compressive bending strengths were influenced by the connection and abutment design of the implant system, however endurance limits were affected more considerably by the connection design.

Analysis of groundwater level change using groundwater monitoring network in Miryang area. (지하수관측망을 이용한 밀양지역의 지하수 변화 분석)

  • Baek, Mi Kyung;Sim, Gyu Sung;Kim, Sang Min
    • Proceedings of the Korea Water Resources Association Conference
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    • 2019.05a
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    • pp.221-221
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    • 2019
  • 기후변화로 인한 가뭄대비가 상시체제가 된 요즈음, 농업용수의 안정적인 공급을 위하여 가뭄 등의 비상시 지표수는 물론이고 지하수의 공급 가능량에 대해서도 국가적 관리가 필요한 실정이다. 지하수관리를 위해 국가 최상위 계획인'지하수관리기본계획(2012~2021)'이 수립되었고, 지하수의 장기적인 수량, 수질 관리를 위해 국가지하수관측망, 지역지하수관측망(보조지하수관측망), 수질측정망, 해수침투관측망 등 광역과 지역단위로 크게 나누어 지하수관측이 이루어지고 있다. 국가지하수관측망은 지하수법에 의거하여 전국의 주요지점(2016년 말 기준 412개소)에 관측소를 설치하여 수위 및 수질의 변동실태를 광역적으로 분석함이 목적이며, 보조지하수관측망은 국가지하수관측망과 연계하고 보완하기 위한 기능으로서, 지역별 주요 관측지점의 수위, 수질자료를 획득하며, 2018년 9월 현재 3,429개소가 설치되어있다. 본 연구에서는 지역지하수 관측망 중 경남밀양지역에 설치된 관측정 31개소에 대해 수위와 수질을 장기 분석하였다. 밀양지역의 보조지하수관측망 설치는 지하수관리계획의 하부계획인'경상남도 지하수관리계획(2015~2025)'에 의거 2012년에 6개소의 관측공이 설치를 시작으로, 2013년 7개소, 2014년 10개소, 2015년 8개소를 설치하여 총 31개소의 설치를 완료하였고, 2016년부터 2019년 현재까지 전체 관측정 31개소에 대하여 관측 운영 중이다. 본 연구에서는 2013년 1월~2019년 1월까지 지역의 누적강수량과 지하수위 및 수질변화를 관측하였다. 전 관측정에 대해 수위(GL.m), 수질(온도, EC)은 1시간 주기로 관측하였으며, 연 2회 생활용수 기준(19항목)의 수질검사를 실시하고, 지하수성분의 지질학적 기원분석을 위한 양음이온 분석을 연 1회 실시하였다. 관측정의 양수능력 변화관측을 위해 대수성 시험을 연 1회 실시하였고, 관측정의 특성상 장기간 미사용 관정이므로 최적의 상태유지를 위해 연1회 공내세척을 실시하였다. 또한, 관측정의 지형별 차이를 분석하기 위해 관측정의 설치위치를 산악, 강변, 기타 지역으로 구분하고, 각각의 대표관정에 대해 지형에 의한 서로 다른 영향을 분석하였고, 관측정의 심도별 변화를 알기위해 동일지역에 충적, 안반 관측정을 따로 설치하고 관측하여 지표수와 지하수의 심도별 영향의 차이를 분석하였다. 동일지역의 관측결과 평균 5m이하의 수위변화를 보이나, 5m 이상의 수위변동을 보이는 관측망은 15년 14개소 17년 19개소로 증가추세를 보이며, 이는 주로 밀집된 시설하우스 단지의 수막재배를 위한 겨울철 지하수 사용량 증가가 원인인 것으로 판단된다. 밀양지역은 강변지역에 밀집된 시설하우스단지의 동절기 수막재배를 위한 지하수 과다사용으로 수위급감 및 수량부족현상이 반복되고 있어, 예방과 대책강구를 위해 지표수의 함양과 지하수사용량의 상관관계 분석과 자료축적 및 추가연구를 위한 장기관측이 요구된다.

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The composition and structure of Archival Information Packages(AIP) for a long-term preservation of electronic records (전자기록의 장기보존을 위한 보존정보패키지(AIP) 구성과 구조)

  • YIM, Jin-Hee
    • The Korean Journal of Archival Studies
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    • no.13
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    • pp.41-90
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    • 2006
  • It's needed for the archivists to design a flexible and stable ERMS(Electronic Records Management System) which can ingest and store records through a consistent way and let users search and use records easily what they want. The basis of the design for ERMS are the conceptual composition and the logical and physical structure of the records when they are stored and managed in the ERMS. This paper explains the process of defining components and designing structure of electronic records using 3-layered approaches which consist of conceptual, logical and physical layer and shows advantages of this approaches. After benchmarking the information models of OAIS which is a reference model for the long-term preservation of digital information objects, this paper applies the model of AIP to a record as a 'Record AIP' and discusses the composition and structure of it. It's a critical task to identify mandatory or optional metadata groups which consists of the 'Record AIP's in the conceptual layer. This paper emphases that the metadata group related to services for the record information to users is required as a result of benchmarking OAIS information models. Various issues about the structure of 'Record AIP's are discussed according to the kind of preservation strategy such as migration or emulation and whether the encapsulation of records is required or not in the logical layer.