Small-scale turbulent fluctuations beyond Taylor's frozen-flow hypothesis

The space-time cross-correlation function C-T(r, tau) of local temperature fluctuations in turbulent Rayleigh-Benard convection is obtained from simultaneous two-point time series measurements. The obtained C-T(r, tau) is found to have the scaling form C-T(r(E), 0) with r(E)=[(r-U tau)(2)+ V-2 tau(2)](1/2), where U and V are two characteristic velocities associated with the mean and rms velocities of the flow. The experiment verifies the theory and demonstrates its applications to a class of turbulent flows in which the requirement of Taylor's frozen flow hypothesis is not met.

南美白对虾（Penaeus vannamei Boone,1931)卵子质量的形态学评估

1）本文描述了南美白对虾正常的卵子形态及发生特点，以及受精卵和非受精卵的形态学鉴别方法。2）从生产的角度出发提出了评估卵子质量的五项指标：同批卵子规格的一致程度，卵子的沉降速度，孵化膜的抗变形能力，4－8细胞期的分裂特点，扩膜卵在同批卵中所占的比例。除此外，对于亲虾持续产卵与所产卵子质量的关系等也作了相应的探讨。