DR DOS V6.0压缩盘(COMPRESSED DISK)乃高效使用硬盘空间技术产物,它将MS(PC)DOS文件的压缩——复原有机地融合于磁盘读写操作过程.准确性极高,速度也快,又无需应答,罕被察觉,犹如运行于常规硬盘,其总容量可高达4GB(512MB×8分区)。...DR DOS V6.0压缩盘(COMPRESSED DISK)乃高效使用硬盘空间技术产物,它将MS(PC)DOS文件的压缩——复原有机地融合于磁盘读写操作过程.准确性极高,速度也快,又无需应答,罕被察觉,犹如运行于常规硬盘,其总容量可高达4GB(512MB×8分区)。 通过对数据压缩处理(压缩率视文件类型及长度而异详载有关资料),绝大多数文件字节数减少,硬盘得以容纳更多的数据。由于压缩盘上文件长度显示保持原值不变。而系统对压缩盘总字节数统以常规(实际Acatal)总字节数近倍显示,貌似盘容量增加。有称增容一倍,似欠确切。展开更多
To deal with the effect of compressible fluids on the supercavitating flow over the subsonic disk cavitator of a projectile, a finite volume method is formulated based on the ideal compressible potential theory. By us...To deal with the effect of compressible fluids on the supercavitating flow over the subsonic disk cavitator of a projectile, a finite volume method is formulated based on the ideal compressible potential theory. By using the continuity equation and Tait state equation as well as Riabouchinsky closure model, an“inverse problem”solution is presented for the supercavitating flow. According to the impenetrable condition on the surface of supercavity, a new iterative method for the supercavity shape is designed to deal with the effect of compressibility on the supercavity shape, pressure drag coefficient and density field. By this method, the very low cavitation number can be computed. The calculated results agree well with the experimental data and empirical formula. At the subsonic condition, the fluid compressibility will make supercavity length and radius increase. The supercavity expands, but remains spheroid. The effect on the first 1/3 part of supercavity is not obvious. The drag coefficient of projectile increases as the cavitation number or Mach number increases. With Mach number increasing, the compressibility is more and more significant. The compressibility must be considered as far as the accurate calculation of supercavitating flow is concerned.展开更多
Loading history and age are factors for disc degeneration and disc biomechanics; however, their relationship is unclear. To evaluate disc biomechanics, we conducted an experimental, anatomical and numerical approach t...Loading history and age are factors for disc degeneration and disc biomechanics; however, their relationship is unclear. To evaluate disc biomechanics, we conducted an experimental, anatomical and numerical approach to distinguish discs with mild and severe degeneration. In the experimental procedure, 10 cadaveric lumbar discs are tested to static and dynamic compression, and the elastic and viscous moduli and the dynamic parameters are reported. The morphology of disc degeneration is gained with MRI （magnetic resonance imaging） and used to generate a nonlinear finite element model of a degenerated disc, and assisted with the experimental results in order to numerically investigate the distribution of stresses and strains within the disc. The results show a promising methodology for the study of intervertebral disc biomechanics and in general other tissues, organs and medical devices.展开更多
文摘DR DOS V6.0压缩盘(COMPRESSED DISK)乃高效使用硬盘空间技术产物,它将MS(PC)DOS文件的压缩——复原有机地融合于磁盘读写操作过程.准确性极高,速度也快,又无需应答,罕被察觉,犹如运行于常规硬盘,其总容量可高达4GB(512MB×8分区)。 通过对数据压缩处理(压缩率视文件类型及长度而异详载有关资料),绝大多数文件字节数减少,硬盘得以容纳更多的数据。由于压缩盘上文件长度显示保持原值不变。而系统对压缩盘总字节数统以常规(实际Acatal)总字节数近倍显示,貌似盘容量增加。有称增容一倍,似欠确切。
基金Foundation item： Supported by the National Natural Science Foundation of China （Grant No. 51309230）, and China Postdoctoral Science Foundation （Nos. 2014T70992 and 2013 M542531）We would like to thank Dr. Tao Miao for closely following our work and making several useful suggestions.
文摘To deal with the effect of compressible fluids on the supercavitating flow over the subsonic disk cavitator of a projectile, a finite volume method is formulated based on the ideal compressible potential theory. By using the continuity equation and Tait state equation as well as Riabouchinsky closure model, an“inverse problem”solution is presented for the supercavitating flow. According to the impenetrable condition on the surface of supercavity, a new iterative method for the supercavity shape is designed to deal with the effect of compressibility on the supercavity shape, pressure drag coefficient and density field. By this method, the very low cavitation number can be computed. The calculated results agree well with the experimental data and empirical formula. At the subsonic condition, the fluid compressibility will make supercavity length and radius increase. The supercavity expands, but remains spheroid. The effect on the first 1/3 part of supercavity is not obvious. The drag coefficient of projectile increases as the cavitation number or Mach number increases. With Mach number increasing, the compressibility is more and more significant. The compressibility must be considered as far as the accurate calculation of supercavitating flow is concerned.
文摘Loading history and age are factors for disc degeneration and disc biomechanics; however, their relationship is unclear. To evaluate disc biomechanics, we conducted an experimental, anatomical and numerical approach to distinguish discs with mild and severe degeneration. In the experimental procedure, 10 cadaveric lumbar discs are tested to static and dynamic compression, and the elastic and viscous moduli and the dynamic parameters are reported. The morphology of disc degeneration is gained with MRI （magnetic resonance imaging） and used to generate a nonlinear finite element model of a degenerated disc, and assisted with the experimental results in order to numerically investigate the distribution of stresses and strains within the disc. The results show a promising methodology for the study of intervertebral disc biomechanics and in general other tissues, organs and medical devices.
