引压管路对动态差压检测影响的分析

该文应用流体阻抗法的有关理论，分析了动态差压检测系统中引压管路的有关参数对测量动态特性的影响。理论分析和有关实验结果表明：检测系统的固有率频的主要决定于两引压管路的基本频率，当引压管路终端腔体很小时，该频率反比于管路的长度。由于实际中存在两个引压管路的不一致，两引压管入口端压力之和的脉动将影响差压检测(表现为压力脉动影响系数)而产生一定的动态误差。

理性力学

经典物理的发展,曾经对科学起了巨大的推动作用。然而,在科学发展的历史过程中,经典物理越来越显示出它的局限性,这没有其他办法,只有发展新的理论来补充和取代它,数学和力学结合的理性力学,就是从经典力学中发展出来的新学科,它解决了许多经典力学解决不了的问题。它应用数学的基本概念和严格的逻辑推理,再从物理原型出发,建立并发展新的力学模型和理论,而经典力学则只是理性力学的特殊情况。

钱老的精神永存——深切缅怀中国力学学会首任理事长钱学森

"中国航天之父"钱学森仙逝的噩耗传来,震惊了中国乃至国际学术界.中国广大力学工作者深感悲痛,纷纷寄托哀思,默默地为钱老祈祷:"钱老,一路走好!"为了纪念这位在中国力学史上曾建立过不朽功勋的伟人,中国力学学会、全国各力学机构和广大会员通过各种方式缅怀我们的首任理事长钱老对新中国力学事业的贡献.

Digital holographic aberration compensation in electron holography

This paper proposes a new digital method to compensate for the aberration of an electron objective lens in electron holography. In this method, the object wavefront in the exit pupil plane is numerically reconstructed from a digitized electron hologram, and is corrected by multiplying it with the conjugated phase-error function. Then, an aberration-free image can be obtained by calculating the Fresnel integral of this corrected wavefront. In comparison with traditional methods, this method is much more convenient and accurate. Some verifying experiments are also presented in this paper. (C) 2003 Society of Photo-optical Instrumentation Engineers.

High power single transverse mode operation of a tapered large-mode-area fiber laser

To get high output power with good beam quality, a tapered section is introduced to large-mode-area (LMA) Yb-doped fiber laser. Output characteristics of the fiber laser without tapered section and with tapered section are compared experimentally. When the launched pump power is 119.1 W, 77.9 W with M-2 3.08 and 56.4 W with M-2 1.14 can be obtained, respectively. The corresponding slope efficiencies are 71.8% and 54.1%, respectively. Although output power of the tapered fiber laser has 30.6% penalty, brightness of it is as much as 5.28 times of the fiber laser without tapered section. Moreover, spectra of them are measured. It is found that tapered section makes lasing wavelength of the fiber laser shorter. (c) 2007 Elsevier B.V. All rights reserved.

上转换亚碲酸盐光纤激光器研究进展

亚碲酸盐玻璃由于具有较低的声子能量，加上其优良的化学稳定性、热稳定性和机械强度及其光学性能，其可作为光纤放大器和上转换光纤激光器的较理想的基质材料。文章介绍了上转换激光器的主要原理，并回顾了亚碲酸盐玻璃上转换激光器的研究进展。