Experimental Study of Effect of Medium Boundary on Light Distribution in Tissue Phantoms

An experimental method for investigating the effect of medium boundary on distributions of light in the biological tissue phantom intralipid is presented. Measurements of distributions of light in intralipid-10% suspensions at 633 nm are described, in which a narrow collimated beam is incident on the surface of the phantoms and into the different depths inside of the phantoms. The experimental results show that the effect of the boundary of the medium on the curves geometry of light distributions is trivial, but the effect on intensity of scattering light is obvious, the maximal relative change of the energy fluence reaches 53.8% and the position of the peak of the energy fluence curve has a shift of 1.1 mm in the reverse direction of incident light for the phantom with albedo a=0.998, and the effect of the boundary is decreased with the increase of the absorption coefficients of tissue phantoms. The experimental results were analysed by the diffusion theory. These studies will be helpful for further understandings of the relation between the boundary of biological tissue and the distribution of light in tissue.     

R~(n+1)中常高阶平均曲率超曲面

本文给出了Rn+1中超曲面的一些积分公式,并利用这些积分公式得到了以球面为边界的常高阶平均曲率超曲面的一些唯一性结果.     

达草灭对莱茵衣藻(Chlamydomonas reinhardtii) 品系遗传后效应的研究

通过将莱菌衣藻（Chlamydomonas reinhardtii）6种达草灭抗性突变株分别与野生型株、丧失合成叶绿素b能力的cbnI-43等基因突变株和精氨酸依赖型突变株杂交对其后代进行四分析与随机分析，发现在Nfr-4-Nfr-7突变株中达草灭抗性状只有单一核基因遗传的性质，而在Nfr-1、Nfr-3～Nfr-7抗性株的抗性性状都是由同一个nfr-1基因（norflurazon resisanse）的突变所决定的，而Nfr-4抗性株的抗性性状是由另一滚突变等位基因nfr-2所决定的。在Nfr-1和Nfr-3抗性株中除了nfr-1基因的突变还有nfr-3基因突变的参与。     

光学非球面二次曲面常数及顶点曲率的研究

受光学非球面制造过程中诸工艺参数的影响,能否保证非球面顶点曲率及二次曲面常数的精度是一个重要问题。基于二次曲面方程,推导出确定光学非球面二次曲面常数k以及顶点曲率半径r的一组算法,并在对一块口径为760mm×200mm标准非球面反射镜的实际测算中进行拟合,经过优化,拟合精度达到Δk=0.015,Δr=0.341mm,从而有效的控制了光学非球面制造过程中的顶点曲率及二次曲面常数的偏差。     

WEIERSTRASS REPRESENTATION FORSURFACES WITH PRESCRIBED NORMALGAUSS MAP AND GAUSS CURVATURE IN H~3

The author obtains a Weierstrass representation for surfaces with prescribed normal Gauss map and Gauss curvature in H3. A differential equation about the hyperbolic Gauss map is also obtained, which characterizes the relation among the hyperbolic Gauss map, the normal Gauss map and Gauss curvature. The author discusses the harmonicity of the normal Gauss map and the hyperbolic Gauss map from surface with constant Gauss curvature in H3 to S2 with certain altered conformal metric. Finally, the author considers the surface whose normal Gauss map is conformal and derives a completely nonlinear differential equation of second order which graph must satisfy.     

非平凡4—调和映照的一个必要条件

本文给出了非平凡４－调和映照的一个必要条件。     

利用排列熵检测近40年华北地区气温突变的研究

运用一种新的动力学突变检测方法——排列熵(permutation entropy，PE)算法，计算并分析了中国华北地区52个站点1960年—2000年逐日平均气温资料的排列熵演化情况，发现中国华北地区气温在20世纪70年代中期、80年代初均发生了较大突变；进一步用经验模态分解(empirical mode decomposition，EMD)方法对排列熵序列进行逐级平稳化处理，结果发现这一地区的气温突变与准10年这一年代际时间尺度的周期变率密切相关，其原因与太阳黑子活动有着密切联系. 关键词： 华北 突变 排列熵算法 经验模态分解     

混合曲率曲面变形方程的Tricomi问题——Ⅱ.解的存在性

本文在很弱的条件下,证明对混合曲率曲面无穷小变形方程的Tricomi问题,存在L₂弱解和H₁强解。     

COMPLETE EXTREMAL SURFACES OF MIXED TYPE IN 3-DIMENSIONAL MINKOWSKI SPACE

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