牛顿第二定律实验中的误差分析

本文是通过对加速度的实验值和理论值进行比较和分析，给出误差的合理范围。     

ALGEBRAIC INDEPENDENCE OF CERTAIN NUMBERS OVER A FIELD OF FINITE TRANSCENDENCE TYPE

The transcendental degree of certain numbers concerned with the exponential funotion over a field of finite transcendence type is considered.     

Cycle control functions and the number of limit cycles

The cycle control function is defined and used to estimate the number of limit cycles for some planar autonomous systems. Some sufficient conditions for the existence of no or at most one limit cycle are given.     

粒子分辨CCT方法中的δ电子效应

提出了切伦科夫相关时间测量(CCT)中初始粒子在辐射体里产生的δ电子的干扰问题,以及降低干扰的方法. 通过模拟计算给出了北京τ-C工厂探测器初步设计中CCT的π/K分辨本领.     

GaAlInP发光材料计算的经验公式

根据已经发表的实验数据，针对镓铝铟磷发光材料的提出了一组经验公式及相应的曲线，作为ＧａＡｌＩｎＰ可见光材料设计的依据或参考。     

FED制作工艺研究

本文介绍了我们开发的ＦＥＤ工艺，包括；硅锥场致发射阵列的制作，栅极制作，阳极支柱的制作和平板透明真空封装，对工艺中的难点及对策作了详细描述。利用上述工艺，已经制成了平板数码管，其栅阴特性理想，阳阴之间也能测得明显的场致发射特性产伴有荧光激发。     

镨掺杂分布对1.3μm光纤放大器特性影响

对掺氟化镨玻璃光纤放大器的小信号增益，用广义的高斯近似公式可获得精确的分析表达。文中研究了限制光纤芯层中央部分的镨掺杂对光纤放大器特性的影响，结果发现限制镨掺杂分布能改进光纤放大器的工作效率，且截止波长比芯层全部均匀掺镨的光纤更长。     

Object boundary location by region and contour deformation

Many applications in image analysis need to distinguish an object from its surroundings. The `snake' method (Kass, 1987) is a well known method to solve such problems by locating the object boundary from an initial plan, but it has the limitation that the distance between the initial plan and the object boundary should be `very small'. The authors present a two-step method, which combines region and contour deformation, to locate the boundary of an object from a designated initial boundary plan. First, they propose a new deformable region model to represent an object, and use the model to locate the boundary of the object by region deformation. This step fills the gap between a fairly rough initial plan and the `snake' method. The resulting boundary is then used as the initial plan of a `snake' method to further refine the boundary. The results of the method are shown in simulated images and MRI images of brain tumour patients     

超稳Y沸石制备技术对沸石铝分布的影响 Ⅱ.均匀铝分布的超稳Y沸石的制备

对水热处理后得到的USY沸石作进一步的酸处理以及采用改进的氟硅酸盐溶液骨架富硅工艺,分别得到了经XPS剖面分析证实为铝分布均匀的超稳Y沸石HAY-Ⅰ和HAY-Ⅱ。IR分析表明,在酸处理过程中从USY沸石中去掉的那部分非骨架铝类与3690cm~(-1)处羟基有关,仍残留在HAY-Ⅰ沸石中的那部分非骨架铝类与3670cm~(-1)和3600cm~(-1)处羟基有关。XRD和化学分析表明HAY-Ⅰ沸石仍含有约50％的非骨架铝类,而HAY-Ⅱ沸石则基本上不含非骨架铝类,HAY-Ⅱ沸石还显示更高的结晶保留度。DTA分析表明,HAY-Ⅰ和HAY-Ⅱ两种沸石的热稳定性均高于USY沸石。     

CAD OF MILLIMETER WAVE OSCILLATORS WITH THE FDHB TECHNIQUE

In this paper the modelling, analysis and optimization of millimeter wave oscillatorsare investigated by using the a frequency-domain harmonic balance technique (FDHB), where theexternal-circuit impedances looking outside from the active device are calculated with a combinedtechnique of modes expansion, Galerkin, and collocation methods. The optimization results arein agreement with the experimental ones, which show the reliability of the presented model andoptimization.