• Title/Summary/Keyword: Rogers

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Taxonomic consideration and Ecological Characteristics of Xylariaceae

  • Lee, Yang-Soo;Han, Sang-Sub
    • Proceedings of the Plant Resources Society of Korea Conference
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    • 2003.10b
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    • pp.19-19
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    • 2003
  • The Xylariaceae Tul. & C. Tul is a family of sphaeriaceous genera with obscure but apparently common ancestry (Rogers, 1979), A central core of genera - Xylaria, Hypoxylon, Rosellinia, Poronia, Podosordaria, Hypocopra, Daldinia, Biscogniauxia, Kretzschmaria, Camillea, Penzigia - are obviously related, regardless of the fact that the generic limits are arguable (Rogers, 1979; Barr, 1990; Eriksson & Hawksworth, 1991; Laessoe, 1994). In general, the family Xylariaceae is primarily defined as a group of stromatic pyrenomycetes with unitunicate asci characterized by a typical apical apparatus and pigmented ascospores having a germ slit (Rogers, 1979). Since Winter (1887) circumscribed the family to include Pyrenomycetes with predominately a dark stroma, dark unveiled spores containing 5 genera: Nummularia Tul. & C. Tul., Hypoxylon Bull., Ustulina Tul. & C.Tul., Poronia Willd. and XylariaHill ex Schrank, many more genera has been added to the family (Dennis, 1961; Eriksson & Hawksworth, 1993; Whalley, 1996). In the absence of a clear circumscription of the family (Rogers, 1994) the agreed number of accepted genera is governed by individual views and there are therefore difference between the proposals for the ascomycetes recognized 35 genera and indicated a further 3 which might belong there. Laessoe reviewed the family and included 37 genera but a few of these were listed as uncertain (Laessoe, 1994). In the most recent accounts Whalley (1996) listed 41 genera but again a number of these were considered uncertain and Ju and Rogers (1996) accepted 39 genera in their interpretation of the family. Since Laessoe (1994) merged Daldinia and Versiomyces with Hypoxylonand Ju and Rogers (1996) combined Astrocystis with Rosellinia and Helicogermslita, which can be argued strongly against, it is likely that a realistic number of genera will be close to 40 (Whalley, 1996; Table 1).

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Taxonomic consideration and Ecological Characteristics of Xylariaceae

  • Lee, Yang-Soo;Han, Sang-Sub
    • Proceedings of the Plant Resources Society of Korea Conference
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    • 2003.10a
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    • pp.43-49
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    • 2003
  • The Xylariaceae Tul. & C. Tul is a family of sphaeriaceous genera with obscure but apparently common ancestry (Rogers, 1979). A central core of genera - Xylaria, Hypoxylon, Rosellinia, Poronia, Podosordaria, Hypocopra, Daldinia, Biscogniauxia, Kretzschmaria, Camillea, Penzigia - are obviously related, regardless of the fact that the generic limits are arguable (Rogers, 1979; Barr, 1990; Eriksson & Hawksworth, 1991; Laessoe, 1994). In general, the family Xylariaceae is primarily defined as a group of stromatic pyrenomycetes with unitunicate asci characterized by a typical apical apparatus and pigmented ascospores having a germ slit (Rogers, 1979). Since Winter (1887) circumscribed the family to include Pyrenomycetes with predominately a dark stroma, dark unveiled spores containing 5 geners: Nummularia Tul, & C. Tul., Hypoxylon Bull., ustulina Tul. & C.Tul., Poronia Willd. and XylariaHill ex Schrank, many more genera has been added to the family (Dennis, 1961; Eriksson & Hawksworth, 1993; Whalley, 1996). In the absence of the clear circumscription of the family (Rogers, 1994) the agreed number of accepted genera is governed by individual views and there are therefore difference between the proposals for the ascomycetes recognized 35 genera and indicated a further 3 which might belong there. Laessore reviewed the family and included 37 genera but a few of these were listed as uncertain (Laessoe, 1994). In the most recent accounts Whalley (1996) listed 41 genera but again a number of these were considered uncertain and Ju and Rogers (1996) accepted 39 genera in their interpretation of the family. Since Laessoe (1994) merged Daldinia and Versiomyces with Hypoxylonand Ju and Rogers (1996) combined Astrocystis with Resellinia and Helicogermslita, which can be argued strongly against, it is likely that a realistic number of genera will be close to 40(Whalley, 1996; table 1).

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A Study on the Affection of Frequency and Displacement for Nonlinear Viscoelastic Bushing Model (비선형 점탄성 부싱모델에 대한 주파수와 변위의 영향에 대한 연구)

  • Kim, Sung-Jin;Min, Je-Hong;Lee, Seong-Beom
    • Elastomers and Composites
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    • v.38 no.4
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    • pp.334-341
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    • 2003
  • A bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is a hollow cylinder, which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the force applied to the shaft and the relative deformation of a bushing is nonlinear and exhibits features of viscoelasticity. A force-displacement relation for bushings is important for multibody dynamics numerical simulations. For the nonlinear viscoelastic axial response, Pipkin-Rogers model, the direct relation of force and displacement, has been derived from Lianis model and the sinusoidal input was used fer Pipkin-Rogers model, and the affection of displacement with frequency change was studied with Pipkin-Rogers model.

A study on failure diagnosis examples of Large oil filled transformer using dissolved gas analysis (유중가스분석법을 이용한 대용량 변압기 고장진단 사례 고찰)

  • Park, Jin-Yeub;Park, In-Kyoo;Chin, Soo-Hwan
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.740_741
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    • 2009
  • 발전소에 설치된 대용량 변압기의 고장사례에 절연유 온도에 따른 가스발생 형태, 가연성가스 성분비를 이용한 Rogers Ratio 법, 발생가스별 고장형태 및 원인분석 방법을 적용하여 고장원인을 진단하고 실제 확인된 고장원인을 고찰하였다. 사례 1은 저압측 탭권선이 과열로 손상된 사례로 온도에 따른 가스발생 형태 및 발생 가스별 고장 형태를 이용한 진단결과는 $300^{\circ}C$이상에서 과열이 된 것으로 진단되어 거의 일치하나 Rogers Ratio 법을 적용하면 $150^{\circ}C$ 정도에서 저온과열된 것으로 진단되어 약간의 차이를 보였다. 사례 2는 변압기 철심의 Burr 발생, 철심간 단락으로 인한 과열 및 아크가 발생된 고장으로 가스발생 패턴이 절연유 온도에 따른 가스발생 형태 및 사례 1과는 차이가 있고 특히, 내부 아크에 의해 발생되는 아세틸렌($C_2H_2$)은 계속 증가하는 반면 "Hot Metal Gas"중의 하나인 에탄($C_2H_6$)은 미량으로 특이한 가스발생형태를 보였다. Rogers Ratio 법과 발생가스별 고장 형태 및 원인분석법에 의한 진단결과는 일치하였다.

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A Study of A Nonlinear Viscoelastic Model for Elastomeric Bushing in Radial Mode (일래스토메릭 부싱의 반경방향모드 비선형 점탄성 모델연구)

  • 이성범;최종근;민제홍
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.5
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    • pp.204-209
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    • 2003
  • An elastomeric bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is an elastomeric hollow cylinder which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the load applied to the shaft or sleeve and the relative deformation of elastomeric bushing is nonlinear and exhibits features of viscoelasticity. A load-displacement relation for elastomeric bushing is important for dynamic numerical simulations. A boundary value problem for the bushing response leads to the load-displacement relation which requires complex calculations. Therefore, by modifying the constitutive equation fur a nonlinear viscoelastic incompressible material developed by Lianis, the data fur the elastomeric bushing material was obtained and this data was used to derive the new load-displacement relation for radial response of the bushing. After the load relaxation function for the bushing is obtained from the step displacement control test, Pipkin-Rogers model was developed, Solutions were allowed fur comparison between the results of Modified Lianis model and those of the proposed model. It is shown that the proposed Pipkin-Rogers model is in very good agreement with Modified Lianis model.

A Study of A Nonlinear Viscoelastic Model for Elastomeric Bushing in Radial Mode (일래스토메릭 부싱의 반경방향모드 비선형 점탄성 모델연구)

  • Lee, Seong-Beom
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.415-419
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    • 2003
  • An elastomeric bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is an elastomeric hollow cylinder which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the load applied to the shaft or sleeve and the relative deformation of elastomeric bushing is nonlinear and exhibits features of viscoelasticity. A load-displacement relation for elastomeric bushing is important for dynamic numerical simulations. A boundary value problem for the bushing response leads to the load-displacement relation which requires complex calculations. Therefore, by modifying the constitutive equation for a nonlinear viscoelastic incompressible material developed by Lianis, the data for the elastomeric bushing material was obtained and this data was used to derive the new load-displacement for radial response of the bushing. After the load relaxation function for the bushing is obtained from the step displacement control test, Pipkin-Rogers model was developed. Solutions were allowed for comparison between the results of Modified Lianis model and those of the proposed model. It is shown that the proposed Pipkin-Rogers model is in very good agreement with Modified Lianis model.

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A Study of A Nonlinear Viscoelastic Model for Elastomeric Bushing in Radial Mode (일래스토메릭 부싱의 반경방향모드 비선형 점탄성 모델연구)

  • 이성범;류재평
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.703-708
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    • 2002
  • An elastomeric bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is an elastomeric hollow cylinder which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the load applied to the shaft or sleeve and the relative deformation of Elastomeric bushing is nonlinear and exhibits features of viscoelasticity. A load-displacement relation fur elastomeric bushing is important fur dynamic numerical simulations. A boundary value problem for the bushing response leads to the load-displacement relation which requires complex calculations and is hence unsuitable. Therefore, by modifying the constitutive equation for a nonlinear viscoelastic incompressible material developed by Lianis, the data fur the elastomeric bushing material was obtained and this data was used to derive the new load-displacement relation fur radial response of the bushing. After the load relaxation function for the bushing is obtained from the step displacement control test, Pipkin-Rogers model was developed. Solutions were allowed for comparison between the results of Modified Lianis model and those of the proposed model. It is shown that the proposed Pipkin-Rogers model is in very good agreement with Modified Lianis model.

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A Study of a Nonlinear Viscoelastic Model for Elastomeric Bushing in Radial Mode

  • Lee, Seong-Beom;Park, Jong-Keun;Min, Je-Hong
    • International Journal of Precision Engineering and Manufacturing
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    • v.5 no.2
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    • pp.16-21
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    • 2004
  • An elastomeric bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. The relation between the load applied to the shaft or sleeve and the relative displacement of elastomeric bushing is nonlinear and exhibits features of viscoelasticity. A load-displacement relation for elastomeric bushing is important fur dynamic numerical simulations. A boundary value problem fur the bushing response leads to the load-displacement relation, which requires complex calculations. Therefore, by modifying the constitutive equation for a nonlinear viscoelastic incompressible material developed by Lianis, the data for the elastomeric bushing material was obtained and this data was used to derive the new load-displacement relation for radial response of the bushing. After the load relaxation function for the bushing was obtained from the step displacement control test, Pipkin-Rogers model was developed. Solutions were allowed for comparison between the results of the modified Lianis model and those of the proposed model. It was shown that the proposed Pipkin-Rogers model was in very good agreement with the modified Lianis model.