• 제목/요약/키워드: High Capacity

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공단지역에서 생육하는 가로수 27종의 항산화특성과 잠재적 환경정화능력 (Antioxidant Characteristics and Phytoremediation Potential of 27 Taxa of Roadside Trees at Industrial Complex Area)

  • 한심희;이재천;오창영;김판기
    • 한국농림기상학회지
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    • 제8권3호
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    • pp.159-168
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    • 2006
  • 대기오염물질을 정화하기에 적합한 수종을 탐색하기 위하여, 공단지역의 가로수로 식재된 27개 수종의 잎에서 항산화 능력, 과산화 지질 함량 및 질소함량을 조사하였다. 2깨 수종 중 항산화 능력이 가장 높은 수종은 개잎갈나무(91.4%) 이었고, 가장 낮은 수종은 벽오동(56.9%) 이었다. MDA함량이 가장 적은 수종은 배롱나무와 은행나무였으나, 양버즘나무, 구실잣밤나무, 후박나무 및 향나무에서는 높은 MDA 함량이 측정되었다. 낙엽활엽수의 항산화 능력은 상록수의 항산화 능력과 뚜렷한 차이가 없었으나, 낙엽활엽수의 MDA 함량은 상록수의 MDA 함량보다 낮게 나타났다. 27개 수종은 항산화 능력과 과산화지질 함량을 기준으로 하여 다음과 같이 4개의 범주로 구분하였다. 범주 I은 높은 항산화 능력과 낮은 과산화지질 함량을 가진 수종, 범주 II는 높은 항산화 능력과 높은 과산화지질 함량을 가진 수종, 범주 III은 낮은 항산화 능력과 낮은 과산화지질 함량을 가진 수종, 범주 IV는 낮은 항산화 능력과 높은 과산화 지질 함량을 가진 수종. 이들 4개 범주에 속하는 수종은 각각 7종(범주 I), 6종(범주 II), 8종(범주 3), 6종(범주 IV) 이었다. 높은 항산화 능력을 가진 범주 I과 II의 수종들은 낮은 질소함량을 나타냈으나, 낮은 항산화능력을 가진 범주 III과 IV의 수종들은 높은 질소함량을 나타냈다. 그러나 범주 I과 II에 속하는 메타세코이아, 굴피나무, 양버즘나무는 예외적으로 높은 항산화 능력과 높은 질소함량을 나타냄으로써 이들 수종들은 공단지역의 식재 수종으로 적합한 것으로 판단되었다.

Moment redistribution of continuous composite I-girder with high strength steel

  • Joo, Hyun Sung;Moon, Jiho;Sung, Ik-Hyun;Lee, Hak-Eun
    • Steel and Composite Structures
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    • 제18권4호
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    • pp.873-887
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    • 2015
  • The continuous composite I-girder should have a sufficient rotation capacity (or ductility) to redistribute the negative bending moment into an adjacent positive bending moment region. However, it is generally known that the ductility of the high strength steel is smaller than that of conventional steel, and application of high strength steel can cause ductility problems in a negative moment region of the I-girder. In this study, moment redistribution of the continuous composite I-girder with high strength steel was studied, where high strength steel with yield stress of 690 MPa was considered (the ultimate stress of the steel was 800 MPa). The available and required rotation capacity of the continuous composite I-girder with high strength steel was firstly derived based on the stress-strain curve of high strength steel and plastic analysis, respectively. A large scale test and a series of non-linear finite element analysis for the continuous composite I-girder with high strength steel were then conducted to examine the effectiveness of proposed models and to investigate the effect of high strength steel on the inelastic behavior of the negative bending moment region of the continuous composite I-girder with high strength steel. Finally, it can be found that the proposed equations provided good estimation of the requited and available rotation capacity of the continuous composite I-girder with high strength steel.

고강도 경량콘크리트를 사용한 철근콘크리트 T 형보의 전단성능 (A Study on Shear Capacity of High Strength Lightweight Reinforced Concrete T-Beams)

  • 김진수;김원호;박성무
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1993년도 가을 학술발표회 논문집
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    • pp.220-225
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    • 1993
  • This paper is an experimental study on shear capacity of the high strength lightweight reinforced concrete beams with shear-depth ratio between 1.5 and 2.5. Thirteen T & rectangular beams were tested to determine their diagonal cracking and ultimate shear capacity. The major variables are shear span-depth ratio (a/d=1.5, 2.0, 2.5), concrete compressive strength(f'c=210, 24., 270㎏/㎠) and tensile steel ratio( =0.6, 1.2%). Based on results obtained from experiment of high strength lightweight reinforced concrete Beam & normal concrete, the following conclusions were drawn. (1) The shear capacity of high-strength lightweight concrete is less 15% than that of normal concrete under same condition. (2) As the results of Comparing this experimental datas with other various formulas. It is regarded that ACI 318-89 shear strength formula related tensile strength is proper to design formula of shear strength of high-strength lightweight reinforced concrete using lightweight concrete.

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대구경 현장타설말뚝의 대용량 양방향 말뚝재하시험 분석 및 극한지지력 추정을 위한 수치해석 연구 (A Numerical Analysis Study for Estimation of Ultimate Bearing Capacity and An Analysis of the High Capacity Bi-directional Pile Load Tests of the Large-diameter Drilled Shafts)

  • 남문석;김상일;홍석우;황성춘;최용규
    • 한국지반환경공학회 논문집
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    • 제12권10호
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    • pp.63-72
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    • 2011
  • 초고층 건축물 기초의 고용량 하중 지지능력을 확인할 수 있는 가장 현실적인 방안인 고유압방식의 고용량 양방향 말뚝재하시험을 2개 현장에서 실시하였다. 고유압 복동식 양방향 말뚝재하시험은 정재하시험 시 재하용량 한계와 현장조건의 제약을 극복 할 수 있는 가장 현실적인 방안으로 볼 수 있었으며 고용량이 필요한 시험말뚝에 대한 재하시험에 매우 유용한 시험방법으로 판단되었다. 2개의 사례에서 계산된 설계하중 충족비는 각각 3.3, 2.1이었으므로 사례(P-2)에서 1방향 재하하중을 다소 작게 재하하였더라면 말뚝기초의 안정성을 실증적으로 확인하지 못하였을 것으로 판단되었다. 초고용량의 양방향 말뚝재하시험에서 설정한 최대하중까지 재하하더라도 말뚝 및 지반의 극한상태를 확인하는 것은 쉽지 않았으므로 대구경 현장타설말뚝의 극한지지력을 추정하기 위하여 2개의 고용량 대구경 현장타설말뚝에 대한 수치해석을 실시하였다.

Seismic tests of RC shear walls confined with high-strength rectangular spiral reinforcement

  • Zhao, Huajing;Li, Qingning;Song, Can;Jiang, Haotian;Zhao, Jun
    • Steel and Composite Structures
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    • 제24권1호
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    • pp.1-13
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    • 2017
  • In order to improve the deformation capacity of the high-strength concrete shear wall, five high-strength concrete shear wall specimens confined with high-strength rectangular spiral reinforcement (HRSR) possessing different parameters, were designed in this paper. One specimen was only adopted high-strength rectangular spiral hoops in embedded columns, the rest of the four specimens were used high-strength rectangular spiral hoops in embedded columns, and high-strength spiral horizontal distribution reinforcement were used in the wall body. Pseudo-static test were carried out on high-strength concrete shear wall specimens confined with HRSR, to study the influence of the factors of longitudinal reinforcement ratio, hoop reinforcement form and the spiral stirrups outer the wall on the failure modes, failure mechanism, ductility, hysteresis characteristics, stiffness degradation and energy dissipation capacity of the shear wall. Results showed that using HRSR as hoops and transverse reinforcements could restrain concrete, slow load carrying capacity degeneration, improve the load carrying capacity and ductility of shear walls; under the vertical force, seismic performance of the RC shear wall with high axial compression ratio can be significantly improved through plastic hinge area or the whole body of the shear wall equipped with outer HRSR.

경상북도 일반고의 교육역량 제고를 위한 기본방향과 성공적인 정착방안 탐색 (The Study of Basic Direction and Successful Fixation Way for Enhancing Educational Capacity of General High School in Gyeongsangbuk-do)

  • 정일환
    • 비교교육연구
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    • 제24권3호
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    • pp.1-23
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    • 2014
  • 본 연구는 고교 다양화 및 특성화고 육성 정책으로 인해 상대적으로 불이익을 받고 있는 일반고의 교육역량 강화 필요성을 인식하고, 현재 일반고가 안고 있는 문제점 등을 진단하여 장 단기적인 관점에서 경상북도의 일반고 육성방안을 다각적으로 마련 제시하는 데 그 목적이 있다. 이를 위해 먼저, 박근혜정부의 교육정책기조와 경상북도 교육정책 방향, 경북지역 일반고 교육현황, 일반고 교육역량 강화방안의 주요 내용 등을 살펴보았다. 교육부의 일반고 교육역량 강화방안에 기초하여 제시된 경상북도 일반고 교육역량 제고의 주요 추진과제로는 (1) 진로별 맞춤형 교육과정 편성 운영의 자율성 확대, (2) 일반고 학생을 위한 진로직업 교육 확대, (3) 위기학생 지원 프로그램 강화, (4) 일반고 High-up 프로그램 지원 강화 등을 들 수 있다. 이와 같은 일반고 교육역량 강화를 위한 주요 추진과제들이 학교현장에서 성공적으로 정착 운영되기 위해서는 개별 일반고의 지역적 환경과 특성을 고려한 학교단위 책임경영제의 정착, 학교경영에 있어 총체적 질 관리 적용, 그리고 협동적 학교조직문화 형성이 구축되어야 할 것이다. 그리고 글로벌 민주시민 양성, 2009 개정 교육과정에서 추구하는 인간상, 그리고 경상북도교육청에서 제시하고 있는 '새로운 생각과 참된 마음을 지닌 인재'를 육성하기 위한, 즉 경상북도 일반고 교육역량 제고를 위한 구체적인 실천과제와 전략들도 제시하였다.

초고층에서의 현장타설말뚝 재하시험방법 고찰 (The Study of Load Test Method for In-Site Casting Pile In High Rise Building.)

  • 김대학;홍영길;한성무;구웅회;박찬덕
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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    • pp.385-392
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    • 2008
  • Modern city have had a lot of high-rise building in high standards and multi-level performance. Using of city space reach better stages by using integration. These skyscraper have increased working load on ground. that building is efficiently designed for that soil capacity is well applied. With material side, big size pile, high strength concrete and high strength steel is used for that getting enough lobby space and resisting load increased of high-rise building. limit load test and load transmitted test can make soil capacity optimized. By the way, method of measuring pile capacity is more advanced and bigger. pile type applied by high rise building have underground excavation space, also reflect regional soil property and have some fact reviewed. A lot of high rise building recently is built as land mark in Seoul, Busan and Incheon. about method of measuring capacity of foundation pile, example of construction field is compared and reviewed.

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High-strength RC columns subjected to high-axial and increasing cyclic lateral loads

  • Bhayusukma, Muhammad Y.;Tsai, Keh-Chyuan
    • Earthquakes and Structures
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    • 제7권5호
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    • pp.779-796
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    • 2014
  • This experimental investigation was conducted to examine the behavior and response of high-strength material (HSM) reinforced concrete (RC) columns under combined high-axial and cyclic-increasing lateral loads. All the columns use high-strength concrete ($f_c{^{\prime}}$=100MPa) and high-yield strength steel ($f_y$=685MPa and $f_y$=785MPa) for both longitudinal and transverse reinforcements. A total of four full-scale HSM columns with amount of transverse reinforcement equal to 100% more than that required by earthquake resistant design provisions of ACI-318 were tested. The key differences among those four columns are the spacing and configuration of transverse reinforcements. Two different constant axial loads, i.e. 60% and 30% of column axial load capacity, were combined with cyclically-increasing lateral loads to impose reversed curvatures in the columns. Test results show that columns under 30% of axial load capacity behaved much more ductile and had higher lateral deformational capacity compared to columns under the 60% of axial load capacity. The columns using closer transverse reinforcement spacing have slightly higher ductility than columns with larger spacing.

Electrokinetic정화시 토질의 완충능을 고려한 시료내의 pH변화 (pH Variation In Soils Considering Buffer Capacity during Electrokinetic Extraction)

  • 오승록;한상재;김수삼;조성호
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2001년도 봄 학술발표회 논문집
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    • pp.585-590
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    • 2001
  • Physicochemical phenomena in soils are dependent upon pH when using electrokinetic extraction for the contaminants removal especially for heavy metals. pH variation in soils is affected on H$\^$+/ and OH ̄ ions produced by electrolysis reaction and buffer capacity of soil. High amount of heavy metals are retained in the soils if the soil buffer capacity remains high enough to resist a change in pH. Therefore, accurate pH estimation of soil is important in the application of electrokinetic mechanism for decontamination and understanding of subsurface physicochemical characteristics is also required as well as considering buffer capacity for the enhanced methods application. For these, buffer capacity and pH distribution were measured for the four soils, and also compared with modeling results. The results of buffer modeling were good agreement with experimental data. It is showed that four soils were effected by buffer capacity

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Evaluations of Si based ternary anode materials by using RF/DC magnetron sputtering for lithium ion batteries

  • 황창묵;박종완
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2010년도 제39회 하계학술대회 초록집
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    • pp.302-303
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    • 2010
  • Generally, the high energy lithium ion batteries depend intimately on the high capacity of electrode materials. For anode materials, the capacity of commercial graphite is unlike to increase much further due to its lower theoretical capacity of 372 mAhg-1. To improve upon graphite-based negative electrode materials for Li-ion rechargeable batteries, alternative anode materials with higher capacity are needed. Therefore, some metal anodes with high theoretic capacity, such as Si, Sn, Ge, Al, and Sb have been studied extensively. This work focuses on ternary Si-M1-M2 composite system, where M1 is Ge that alloys with Li, which has good cyclability and high specific capacity and M2 is Mo that does not alloy with Li. The Si shows the highest gravimetric capacity (up to 4000mAhg-1 for Li21Si5). Although Si is the most promising of the next generation anodes, it undergoes a large volume change during lithium insertion and extraction. It results in pulverization of the Si and loss of electrical contact between the Si and the current collector during the lithiation and delithiation. Thus, its capacity fades rapidly during cycling. Si thin film is more resistant to fracture than bulk Si because the film is firmly attached to the substrate. Thus, Si film could achieve good cycleability as well as high capacity. To improve the cycle performance of Si, Suzuki et al. prepared two components active (Si)-active(Sn, like Ge) elements film by vacuum deposition, where Sn particles dispersed homogeneously in the Si matrix. This film showed excellent rate capability than pure Si thin film. In this work, second element, Ge shows also high capacity (about 2500mAhg-1 for Li21Ge5) and has good cyclability although it undergoes a large volume change likewise Si. But only Ge does not use the anode due to its costs. Therefore, the electrode should be consisted of moderately Ge contents. Third element, Mo is an element that does not alloys with Li such as Co, Cr, Fe, Mn, Ni, V, Zr. In our previous research work, we have fabricated Si-Mo (active-inactive elements) composite negative electrodes by using RF/DC magnetron sputtering method. The electrodes showed excellent cycle characteristics. The Mo-silicide (inert matrix) dispersed homogeneously in the Si matrix and prevents the active material from aggregating. However, the thicker film than $3\;{\mu}m$ with high Mo contents showed poor cycling performance, which was attributed to the internal stress related to thickness. In order to deal with the large volume expansion of Si anode, great efforts were paid on material design. One of the effective ways is to find suitably three-elements (Si-Ge-Mo) contents. In this study, the Si based composites of 45~65 Si at.% and 23~43 Ge at.%, and 12~32 Mo at.% are evaluated the electrochemical characteristics and cycle performances as an anode. Results from six different compositions of Si-Ge-Mo are presented compared to only the Si and Ge negative electrodes.

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