COSTAS环解调器设计及实践初探

本文详细介绍自行设计的COSTAS环解调器的工作原理,环路参数选择以及实际工作效果。     

利用微阵列基因芯片研究东海海参(Acaudina leucoprocta)的生理功能

取喂食东海海参60d的ICR小鼠肝脏,制备微阵列基因表达芯片,并与模式小鼠芯片进行杂交,筛选功能基因和差异表达蛋白.从食用海参的鼠肝中共筛选出了4180个基因,其中差异表达基因184个,上调基因107个,下调基因77个.利用MAS.2.0系统对其功能进行分析,结果显示,分子功能上有催化活性的基因占39.86%,结合功能...     

电场差分法理论研究

对均匀大地和二层大地的频率域电场差分法理论曲线进行的计算和研究表明,电场差分法是一种以目标地质体和围岩在电阻率和极化率方面的差异为基础,根据测量到的能明显反映激电响应与电磁耦合响应的比值随频率变化的P参数曲线在性态上的差异来圈划油气藏的一种电法勘探方法. 因为它圈划油气藏的物理基础是油气藏上方与围岩上方测量到的电磁耦合响应和激电响应的差异,所以在圈划油气藏方面,该方法与复电阻率法类似,同样具有找油气的优良性能. 此外,该方法与复电阻率法相比,具有对目标地质体和围岩的电阻率和极化率差异反映灵敏、效率高、成本低等优点,所以它是一种值得推广的找油气的电法勘探方法.     

Linear stability analysis for the differentially heated rotating annulus

We use linear stability analysis to approximate the axisymmetric to nonaxisymmetric transition in the differentially heated rotating annulus. We study an accurate mathematical model that uses the Navier–Stokes equations in the Boussinesq approximation. The steady axisymmetric solution satisfies a two-dimensional partial differential boundary value problem. It is not possible to compute the solution analytically, and thus, numerical methods are used. The eigenvalues are also given by a two-dimensional partial differential problem, and are approximated using the matrix eigenvalue problem that results from discretizing the linear part of the appropriate equations.

A comparison is made with experimental results. It is shown that the predictions using linear stability analysis accurately reproduce many of the experimental observations. Of particular interest is that the analysis predicts cusping of the axisymmetric to nonaxisymmetric transition curve at wave number transitions, and the wave number maximum along the lower part of the axisymmetric to nonaxisymmetric transition curve is accurately determined. The correspondence between theoretical and experimental results validates the numerical approximations as well as the application of linear stability analysis.

A linear stability analysis is also performed with the effects of centrifugal buoyancy neglected. Along the lower part of the transition curve, the results are significantly qualitatively and quantitatively different than when the centrifugal effects are considered. In particular, the results indicate that the centrifugal buoyancy is the cause of the observation of a wave number maximum along the transition curve, and is the cause of a change in concavity of the transition curve.