• 제목/요약/키워드: Free transportation

검색결과 395건 처리시간 0.026초

Free vibration of a steel-concrete composite beam with coupled longitudinal and bending motions

  • Li, Jun;Jiang, Li;Li, Xiaobin
    • Steel and Composite Structures
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    • 제24권1호
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    • pp.79-91
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    • 2017
  • Free vibrations of steel-concrete composite beams are analyzed by using the dynamic stiffness approach. The coupled equations of motion of the composite beams are derived with help of the Hamilton's principle. The effects of the shear deformation and rotary inertia of the two beams as well as the transverse and axial deformations of the stud connectors are included in the formulation. The dynamic stiffness matrix is developed on the basis of the exact general solutions of the homogeneous governing differential equations of the composite beams. The use of the dynamic stiffness method to determine the natural frequencies and mode shapes of a particular steel-concrete composite beam with various boundary conditions is demonstrated. The accuracy and effectiveness of the present model and formulation are validated by comparison of the present results with the available solutions in literature.

교통수요예칙과 가로망설계의 효율화 (Toward the Efficient Integration of Travel Demand Analysis with Transportation Network Design Models)

  • 이인원
    • 대한교통학회지
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    • 제1권1호
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    • pp.28-42
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    • 1983
  • In recent years, significant advances have been made enabling travel demand analysis and network design methods to be used as increasingly realistic evaluation tools. What has been lacking is the integration of travel demand analysis with network design models. This paper reviews some of advanced (integrated) modeling approaches and presents future research directions of integrated modeling system. To design urban transportation networks, it is argued that the travelers' free choice of mode, destination and route should be introduced into transportation network design procedure instead of assuming that trips from a zone to a workplace are fixed or deriving them in a normative procedure to achieve hypothetical system optima.

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여객자동차터미널의 장애물 없는 생활환경 인증 평가에 관한 연구 (A Study on Barrier-free Certification Evaluation of the Bus Terminals)

  • 강병근;강태성;김상운;이주형
    • 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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    • 제22권2호
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    • pp.7-14
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    • 2016
  • Purpose: Caring for weak person in society, which increases the population of the elderly and people with disabilities is essential. By increasing along with the increase of the use of passenger facilities for travelers and pedestrian is increasing the demand for convenient and secure facilities for everyone. The emerging importance of the passenger-related facilities, but a representative study of the bus terminal facilities is lacking. Bus terminals are the most popular passenger facility. Thus, the bus terminal can be conveniently used by anyone in everyday life, however, the applied elements considering the use of the transportation Poor are not sufficient. Methods: This study was conducted to evaluate BF certification standards targeting bus terminals across the country to determine the availability of the transportation Poor in bus terminal. Result: As a result of the bus Terminal possibility BF certified it appeared to be very low. Also, items received the lowest rating of each item was evaluated in the informative facilities and items. Bus terminal is a facility used by the unspecified individuals, the proportion of first-time user is high, but there is a lack of consideration for the transportation Poor bus terminals. Implications: In the future, this study can guide the next research on the application of BF certification standards in bus terminal. Further studies can be presented to the improvement of the BF certification indicator in bus terminal.

병풀 품종별 품질 특성 및 추출 용매별 항산화 활성 (Quality Characteristics of Centella asiatica Species and Antioxidant Activities of Solvent Extracts)

  • 이경행;유광원;배윤정;김채영;주가영;윤지혜
    • 한국식품영양학회지
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    • 제34권3호
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    • pp.255-262
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    • 2021
  • Centella asiatica (CA) is a vegetable that has been used for medicinal purposes for a long time, but it is not well known in Korea. In this study, the approximate analysis, physicochemical properties, free sugars, free amino acids and minerals of native and improved CA cultivated in Chungju area were measured. And the antioxidant contents and activities of CA solvent extracts were measured. There was no significant difference between native and improved species. As for the characteristics of CA, it was confirmed that the improved species had a large weight, size and a tough texture. Glucose was detected in native CA, fructose, glucose and sucrose were detected in improved species. A total of 15 free amino acids were detected and the content was slightly higher in improved species than in native species. The mineral content in CA was slightly higher in the improved species, and the detected minerals were Na, P, Ca, K, Mg and Fe. Polyphenols, ascorbic acid and flavonoids in each extraction solvent (water, 70% and 100% ethanol) were all higher in the improved species than in native species. And it was found that the antioxidant activities of ethanol extracts were higher than that of water.

Ship Manoeuvring Performance Experiments Using a Free Running Model Ship

  • Im, Nam-Kyun;Seo, Jeong-Ho
    • 한국항해항만학회지
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    • 제33권9호
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    • pp.603-608
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    • 2009
  • In this paper, a 3m-class free running model ship will be introduced with its manoeuvring performance experiments. The results of turning circle test and zig-zag test will be explained. The developed system are equipped with GPS, main control computer, wireless LAN, IMU (Inertial Measurement Unit), self-propulsion propeller and driving rudder. Its motion can be controlled by RC (Radio Control) and wireless LAN from land based center. Automatic navigation is also available by pre-programmed algorithm. The trajectory of navigation can be acquired by GPS and it provides us with important data for ship's motion control experiments. The results of manoeuvring performance experiment have shown that the developed free running model ship can be used to verify the test of turning circle and zig-zag. For next step, other experimental researches such as ship collision avoidance system and automatic berthing can be considered in the future.

실리콘 웨이퍼 표면의 saw mark 밀도에 따른 피라미드 구조의 영향 (Effect on the Pyramid Structure with Saw Mark Density of Silicon Wafer Surface)

  • 이민지;박정은;이영민;강상묵;임동건
    • Current Photovoltaic Research
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    • 제5권2호
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    • pp.59-62
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    • 2017
  • Surface texturing is affected the uniformity and size of pyramid with saw mark defect density. To analysis the influence of the saw mark defect density, we textured various si wafer. When the texturing process proceeds without the saw mark removal, silicon wafer of low-saw mark defect density showed small pyramid size of $3.5{\mu}m$ with the lowest average value of the reflectance of 10.6%. When texturing carried out after removal of the saw mark using the TMAH solution, we obtained a reflectance of about 11% and the large pyramid size of $5{\mu}m$. As a result, saw mark wafers showed a better pyramid structure than saw mark-free wafer. This result showed that saw mark can take place more smooth etching by the KOH solution and saw mark-free wafer is determined to be a factor that have a higher reflectance and a large pyramid.

저선량의 UV-C 처리 복숭아의 주요 성분 변화 (Changes in Chemical components of Peach (Prunus persica L. Batsch) Treated with Low Dose UV-C Irradiation)

  • 이경행;장현정;최지혜;반기은;박재희;이유진
    • 한국식품영양학회지
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    • 제26권3호
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    • pp.573-577
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    • 2013
  • 국내산 복숭아의 저장성 증진을 위하여 저선량(0~3.0 $kJ/m^2$)의 UV-C를 조사하고, 저장 중 주요 성분의 변화를 측정하였다. Polyphenol 화합물 함량은 UV 처리시 대조군에 비하여 약간 높은 함량을 보이는 것으로 나타났다. 특히 0.25 $kJ/m^2$ 처리군은 가장 많은 함량을 나타내었다. 저장 과정 중의 polyphenol 화합물의 함량은 대조군 및 UV 처리군 모두 서서히 감소하는 경향이었다. Flavonoid 함량은 대조군 및 UV 처리군 모두 저장하는 동안 특정한 경향을 나타내지는 않는 것으로 나타났다. 복숭아 내 유리당은 UV 처리군 및 대조군 모두 fructose, glucose, maltose 및 sucrose가 검출되었고, 이중 sucrose의 함량이 가장 많았으며, 저장 중 당 함량은 증가하였으며, UV 처리군 및 대조군 모두 유의적인 차이를 보이지 않았다. 유리아미노산은 대조군은 115.38 mg%였으며, UV-C 처리군의 경우, 총 유리아미노산의 함량은 95.92~120.94 mg%로 함량의 차이가 약간 있긴 하지만 유의적인 차이를 보이지 않아, 저선량의 UV-C 처리는 가능할 것으로 판단되었다.