A facile synthesis of per (poly )fluoroalkyl substituted α-amino acid derivatives

Initiated by CrCl3/Fe redox couple, per(poly)fluoroalkyl iodides added to methyl a-acetylamino acrylate, giving B-per(poly)fluoroalkyl a-amino acid derivatives in good yields.     

光抽运双光子激光朗之万量子理论

本文采用朗之万量子理论获得光抽运双光子激光具有双光子损耗时的朗之万方程,进一步获得稳态平均光子数、频率牵引、线宽和动态斯塔克效应,对激光增益来源的分析表明,非相干抽运仅有单双光子两步过程有贡献,而相干抽运,除上述过程外还有单双光子一步过程有贡献,而且,上述两个过程都受到负反馈和饱和因子的制约,线宽与稳态平均光子数无关。 关键词：     

Physico-Chemical Characterization of Yu Guo Beads(1100-771 B. C. ) in China

When was the earliest glass produced in China? This has still been a question so far. Some archaeologists have thought that Yu Guo beads are real glass, the earliest glass(1100-771 B. C. ) in China. However, more details of scientific investigations in this paper show that Yu Guo beads are mainly made of clastic quartz (>95%) with a small amount of clay and sintered under the low temperature(500-600℃). It is not a glassy body, but a kind of polycrystal ornaments.     

FIXED POINTS AND COUPLED FIXED POINTS FOR INCREASING OPERATORS WITH APPLICMIONS TO DIFFERENTIAL INCLUSIONS IN BANACH SPACES

ＦＩＸＥＤＰＯＩＮＴＳＡＮＤＣＯＵＰＬＥＤＦＩＸＥＤＰＯＩＮＴＳＦＯＲＩＮＣＲＥＡＳＩＮＧＯＰＥＲＡＴＯＲＳＷＩＴＨＡＰＰＬＩＣＭＩＯＮＳＴＯＤＩＦＦＥＲＥＮＴＩＡＬＩＮＣＬＵＳＩＯＮＳＩＮＢＡＮＡＣＨＳＰＡＣＥＳＺＨＡＮＧＳＨＩＳＨＥＮＧＡＮＤＨＵ...     

R~n中有界区域上调和函数的积分平均值估计

设={x∈Rⁿ;λ(x<0}是一具有光滑边界的有界区域.给定x₀∈,0-1,m∈N及ε>0足够小,就上的调和函数f证明了和其中M_p(f,r)是f在上的积分平均,grad_jf为f的j次梯度.     

PARADOXICAL EFFECT OF A GnRH AGONIST ON STEROIDOGENESIS IN CULTURED MONKEY GRANULOSA CELLS

In this study we demonstrate: (i) The GnRH agonist exerts a direct dose-dependet stimulative effect on the aromatase activity and progesterone production in cultured monkey granulosa cells; (ii)the stimulative effect on steroidogenesis can be completely blocked by concomitant treatment with a GnRH antagonist, suggesting that the actions of GnRH are mediated through stringent stereospecific recongnition sites; (iii) in addition to the stimulative effect, the GnRH agonist in the presence of gonadotropins also exerts an inhibitory effect, even though the peptide by itself is more effective in the stimulation of steroidogenesis, and the stimulation of gonadotropin on steroidogenesis could be gradually restored by decreasing the concentration of the GnRH agonist in the culture; and (iv) paradoxical effect can also be observed in the presence of cAMP-inducing agents, suggesting that the inhibitory action of the peptide on gonadotropin-induced steroidogenesis is localized at a step distal to the stringent reco     

Dirichlet型空间上的乘子

本文主要根据τ与μ的不同取值分三种情况刻划了Cn中单位球上Dirichlet 型空间上的点乘子空间M(Dτ,Dμ),并通过两个函数的构造表明:当τ≤n时,包含 关系M(Dτ)(?)Dτ和当τ>μ,τ>n-1时,包含关系M(Dτ)(?) M(Dμ)是严格的.     

规则结构多孔填料塔两相流动特性实验研究

本文以空气和水为工质,对规则结构多孔填料塔的气-液逆向流动特性进行了可视化实验,研究了填料塔内气一液两相流动规律.实验结果表明:当液体流量一定时,随着气体流量的增加,压力损失增大;当气体流量一定时,随着液体流量的增加,气相压力损失增加.根据实验结果提出了采用水力雷诺数、韦伯数和无量纲流动参数的填料塔内气-液两相流动阻力系数实验关联式.     

激光标线的原理和实验

根据几何光学知识分析了激光标线原理.理论和实验表明:激光标线长度与激光光束形状、光学元件形状及材料折射率有关.并讨论了激光标线向两侧扩展的原因.