Dynamics of Efficiency Change by Temperature in Diode Pumped Nd：YAG Heat Capacity Laser

We investigate the influence of temperature on the efficiency of diode pumped Nd：YAG heat capacity laser is studied. It is shown that the efficiency of such a laser system is greatly reduced at higher temperature. This bad behaviour is mainly caused by the doped-ion redistribution among various Stark levels of the ground state, and by a thermal equilibrium between the upper laser level and the pump level. Meanwhile, the thermal excitations from the ground state to the lower laser level also play a role. We derive a model to describe those effects, with the considerations of emission spectrum of laser diodes, the subtle Stark structures and the linewidth of absorption and of simulated-emission.     

基于截形式背景的属性约简分析

在模糊概念格中讨论了基于截形式背景的属性约简,其中着重分析了在精度的偏序关系下属性约简的包含关系,并证明了此说法的正确性,进而还举例说明了其正确性;在此基础之上,本文还给出了在用不同精度把模糊概念格转换了经典概念格时造成的误差,并给出其算法,最后举例说明其有效性.     

Relative position determination of a lunar rover using high-accuracy multi-frequency same-beam VLBI

Multi-frequency same-beam VLBI means that two explorers with a small separation angle are simultaneously observed with the main beam of receiving antennas. In the same-beam VLBI, the differential phase delay between two explorers and two receiving telescopes can be obtained with a small error of several picoseconds. The differential phase delay, as the observable of the same-beam VLBI, gives the separation angular information of the two explorers in the celestial sphere. The two-dimensional relative position on the plane-of-sky can thus be precisely determined with an error of less than 1 m for a distance of 3.8×105 km far away from the earth, by using the differential phase delay obtained with the four Chinese VLBI stations. The relative position of a lunar rover on the lunar surface can be determined with an error of 10 m by using the differential phase delay data and the range data for the lander when the lunar topography near the rover and the lander can be determined with an error of 10 m.     

MSP430在大量程浮子式液位计中的应用

在对传统浮子式液位计优缺点进行分析的基础上，介绍了采用TI公司MSP430F133单片机改进传统浮子式液位计液位测量的方法，给出了具体电路的设计方法和软件设计注意事项。     

Structures and stability of N13 cluster

Quantum chemical studies for the nine N₁₃ isomers with low spin were carried out at the UHF/6-31G*, UB3LYP/6-31G* and UMP2/6-311G* levels of theory. The most stable N₁₃ isomer is structure 1 with C_2v symmetry, which contains two separated pentazole rings connected by three nitrogen atoms. The results show that structures 1, 2, 3, 4 and 5 which are composed of the pentazole ring are more stable than the open chain structure 6 and structures 8 and 9 which contain the four- and six-membered rings. This suggests that the pentazole ring is a fundamental stable structural unit, which is applicable not only for the even-numbered nitrogen clusters, but also for the large odd-numbered clusters.     

Morlet小波在确定局部周期中的应用

本文通过引入改进的Morlet小波变换核函数,得到了等幅值的Morlet小波变换(MMWT)和功率谱(MMPS).理论及实验均表明,MMPS不但能够准确的确定信号的局部周期,而且使相同振幅(强度)的谐波产生了相同大小的MMPS,弥补了MPS的不足.对于MMWT还给出了相应的Morlet小波变换尺度与频率转化公式.     

关于算子方程λA2+μA*2=αA*A+βAA*

本文主要是给出Hilbert空间上满足方程 λA²+μA^*2=αA^*A+βAA^* (λ,μ,α,β都是复数)的有界线性算子A的全部形式,并给出它的应用。     

主动成像系统距离选通实验方案设计

 距离选通技术是克服大气后向散射，提高主动成像系统信噪比的有效方法。分析了距离选通的技术要求，分别使用电源调制和机械调制的方法获得了适合用于主动成像系统脉冲光源,并进行了距离选通实验，机械调制方法适用于大功率连续半导体激光器。使用氙灯泵浦YAG激光器实现了对675 m和1 509 m距离目标的主动成像，详细分析了几种方案的利弊并提出了改进方法。     

非负整数格上元素的性质及其在刻画@-Fuzzy关系方程解集中的作用

首先讨论了非负整数格上元素的性质. 从而完全地刻画了非负整数格上@-Fuzzy关系方程(其中@表示inf-α合成)的解集.     

富氧条件下生物质基活性炭负载钾催化剂高选择性还原氮氧化物

研究了富氧环境中生物质基活性炭负载钾催化剂选择性还原氮氧化物的性能。结果表明,与煤基（褐煤）活性炭负载钾催化剂相比,生物质基（木屑）活性炭负载钾催化剂表现出高选择性还原NO能力,在2 h恒温稳态实验过程中能够保持80%的NO还原效率,而C-O₂反应活性仅为18%。X射线衍射、比表面积、X射线光电子能谱以及程序升温脱附实验表征结果显示,生物质基活性炭负载钾催化剂优异的选择性还原NO性能应归因于炭表面钾物种的高度分散性,这与催化剂的高比表面积以及大量的表面氧基团有关。另外,生物质基炭材料还原NO反应产物中具有较高的CO₂选择性。