A High Efficiency Yb3+-doped Fiber Ring Cavity Laser with Narrow Line-widthRound-trip Dispersion Calculation for Martinez Pulse Stretcher

A novel Yb3+-doped fiber ring cavity laser pumped by a 977 nm laser diode is presented with its output laser wavelength of 1060 nm. Based on a fiber Bragg grating (FBG), the laser exhibits 0.20 nm line-width, 7.5 mW laser output power, 40 dB signal-to-noise ratio (SNR) and 66% slope efficiency.This paper proposed a ray-tracing model for the Martinez stretcher, derived the calculation formulae for the stretcher of a grating-spherical mirror system and discussed the error for the total dispersion resulted from the spatial dispersion. The calculated results show that the error could be ignored for the beam returned to the stretcher for the second pass in the wavelength range of 750 nm and 850 nm.     

High repetition rate pulsed laser of twin wavelengths from KTiOPO4 optical parametric oscillation

In this paper, some key techniques of KTiOPO_4 optical parametric oscillation (OPO) laser with repetitive frequencies and twin wavelengths output have been analysed theoretically and studied experimentally in detail. An intracavity optical parametric oscillator (IOPO) has been applied. Operating under 20Hz, laser output energy of more than 38mJ with twin wavelengths 1.57μm and 1.06μm has been achieved. Results of the experiments agree well with the theoretical discussion.     

综合评分法在评审QC小组成果中的应用

正确评价质量管理小组成果的实际水平,对推动群众性质量管理活动有着重要的意义及作用.分析几年来QC成果发表评审工作,发现采用按成果评价内容分大项打分存在以下问题,具体概括为: 1.评优次序与成果实际水平不一致. 2.评审打分拉不开档次,经常出现评分相同的情况。 3.评分标准太概括,难以准确打分. 如果说我们把正确评价QC小组成果实际水平看做是我们的期望目标,不理想的评价结果做为出现的偏差,减少这个偏差就是评价要解决的问题,分析产生偏差原因大体有三个: 1.评委由于受专业和知识面限制,对评价标准掌握程度不同,产生打分差异. 2.企业…     

我們所見到的苏聯中学的化学課堂教学

我們这次到苏联参观訪問,關於中学化学教学方面,接觸的面还是很廣的。共听了六堂课,其中三堂是講新課,三堂是实習課,內容如下: 講新課: 1.莫斯科316号中学十年級鈣的主要化合物及其应用。 2.莫斯科315号中学十年級生鉄的生     

伴有化学反应的磁流体传热传质混合对流流经吸入/喷出多孔楔形体时的局部非相似解

研究伴有化学反应的流经多孔楔形体的,传热传质磁流体的自由、受迫和混合对流.使用结合打靶法的Runge-Kutta-Gill方法,和直到3阶截断误差的局部非相似法,将偏微分的控制方程简化为9个常微分方程.通过Falkner-Skan变换,将边界层控制方程表示为无量纲形式.由于楔形体壁面的吸入/喷出,以及可变的壁面温度和浮力的影响,使得流场呈局部非相似性.就一些特定的无量纲参变数,给出具有3阶截断误差的数值计算.图形显示可变壁面温度和浓度条件下,伴有化学反应时磁场强度对无量纲速度、温度和浓度分布的影响.     

素特征Hamilton超代数的偶部

研究了索特征域上有限维Hamilton李超代数的偶部(h)的结构.首先给出偶部(h)的一个极大理想(3),并证明(h)到(223)的导子可以通过(3)到(223)的导子得到,这里(223)是广义Witt超代数的偶部.接着给出理想(3)的一个生成元集并给出三类(h)到(223)的外导子.利用上面结果,计算零化(h)的非正(Z)-分支的导子.最后,刻画了(h)到(223)的(Z)-次数为奇数以及(Z)-次数为负的齐次导子.     

灰色中立随机线性时滞系统的稳定性分析(英文)

通过使用灰色矩阵覆盖集的分解方法和矩阵范数的性质,构造李雅普诺夫函数,研究了灰色中立随机线性时滞系统的鲁棒稳定性和几乎指数鲁棒稳定性.     

贯彻启发教育思想改革《分析化学》教学

在大力提倡素质教育的21世纪,贯彻启发教育思想很有必要.按照启发的基础,论述以直接感性认识和理性知识以及以实物或教具挂图为基础的启发方法.根据思维活动的形式不同论述对概念、判断、推理和论证的启发方法.     

玫瑰枝、叶中微量元素含量的测定及动态研究

用原子吸收光谱法对大马士革玫瑰枝、叶中Ca、Mg、Fe、Cu、Mn 5种微量元素的含量进行了测定,并研究了不同生理条件、不同器官中5种元素含量的动态变化规律。结果表明:大马士革玫瑰枝叶中含有丰富的Ca、Mg、Fe、Cu、Mn微量元素,元素含量高低顺序依次为:Ca>Mg>Fe>Mn>Cu;玫瑰叶片中的微量元素含量均明显高于枝条,甚至较枝条要高出一个数量级以上;未开花植株和开花植株微量元素含量的动态变化规律总体上基本相似,但是未开花植株的微量元素含量要显著低于开花植株;在生长季节内,5种微量元素含量各呈现不同的动态变化规律,这与植物的生长发育和元素的植物生理功能密切相关。     

Linewidth of electromagnetically induced transparency under motional averaging in a coated vapor cell

The linewidth of electromagnetically induced transparency(EIT) in a coated Rb vapor cell was studied under a magnetic field gradient.The nonlinear broadening of the EIT linewidth with the magnetic field gradient was observed.It was found that the motional averaging of the field gradient was more pronounced at higher laser intensities and larger beam sizes.In the same regime,there was a small linewidth decrease with the increasing magnetic field gradient.We have established a Monte-Carlo model,which gave results in good qualitative agreement with our experiment.Physics pictures for the above phenomena were also suggested.These results provide an understanding of the EIT linewidth behavior under motional averaging,and should be useful for applications in quantum optics and metrology based on coated vapor cells.