期刊：
Journal of Chemical Information and Modeling,2002年42(3):529-533 ISSN：1549-9596
通讯作者：
Liu, YC
作者机构：
[Liu, YC] Nanhua Univ, Inst Engn & Technol, Dept Math & Phys Sci, Hengyang 421001, Hunan, Peoples R China.;Xinjiang Univ, Inst Math & Phys, Urumqi 830046, Xinjiang, Peoples R China.;Huazhong Univ Sci & Technol, Dept Control Sci & Engn, Wuhan 430074, Hubei, Peoples R China.
通讯机构：
[Liu, YC] N;Nanhua Univ, Inst Engn & Technol, Dept Math & Phys Sci, Hengyang 421001, Hunan, Peoples R China.
摘要：
Some 2-D and 3-D graphical representations of DNA sequences have been given by Nandy, Leong and Mogenthaler, and Randic et al., which give visual characterizations of DNA sequences. In this paper, we presented a novel graphical representation of DNA sequences by taking four special vectors in 2-D Cartesian coordinate system to represent the four nucleic acid bases in DNA sequences, so that a DNA sequence is denoted on a plane by a directed walk. It is shown that the new graphical representation of DNA sequences has lower or nondegeneracy.
摘要：
With the increasing use of high-strength concrete (fc > 60 MPa) in building construction, the risk of exposing these structures to high temperatures during a fire has increased significantly. To be able to assess the structural safety of such structures after a fire, it is important that the mechanical properties of the material be well assessed with regard to high-temperature effects. In this context, a study was conducted to investigate the residual mechanical properties of confined and unconfined high-strength concrete (fc = 70 MPa) after a single thermal cycle at 100, 200, 300, 400, 500, 600, 700, 800, and 900°C. An analytical model for the stress-strain relationship for uniaxially loaded high-strength concrete was empirically developed and was shown to be applicable to confined and unconfined concrete after a cycle at a high temperature. The main parameters required to establish the stress-strain relationship are the peak stress, the elastic modulus, and the strain at peak stress. Empirical expressions for these parameters were developed to take into account the temperature and the level of confinement. The knowledge of the residual mechanical properties of concrete is necessary whenever the thermally damaged structure is required to bear a significant share of the loads, even after a severe thermal accident.
