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1.
由激光二极管(LD)输入、输出的关系,得到激光器腔体参数与注入电流的关系,进而给出在设计激光器时遇到的相关限制的方程,以及LD电流与某种形式的电流增益转换因子的关系,根据增益曲线上的最佳工作点可优化腔体长度参数.讨论了共面LD在固定总腔长、固定无源区长度、固定有源与无源区的长度比等条件下有源区长度的优化.  相似文献   

2.
激光测量和惯性测量都可以对物体位置、速度、姿态等物理参数进行测量.其中,激光测量有着测程远、精度高等特点;而惯性测量也有着自主性高,不易受干扰、采样率高等特点.根据FAST项目中对测量的实际要求,分析了在馈源舱动态测量任务中已有的激光测量系统的特点与不足,提出了引入惯性测量系统与激光测量系统结合以达到更好测量效果的方案,并对方案的可行性与实现方法进行了研究.  相似文献   

3.
在论述了光驱动力敏传感器工作原理的基础上.提出了实用化的闭环振荡式的压电晶体测为光驱动方案.采用光反馈稳定的3mWLD做光源.光驱动距离这500m.微功耗为敏传感探头总功耗仅为0.275mW.文中介绍了这种新型传感器的设计思想和实现光驱动的几个关键技术问题.给出了测量力参数的实验曲线.  相似文献   

4.
成强  孙寅聪  敖天勇  王渊旭  张德权 《河南科学》2009,27(12):1562-1565
采用直观的载流子、光子库模型,导出半导体激光器速率方程,得到输入电流、输出光功率的关系以及激光器腔体参数与注入电流的关系,从而给出在设计激光器时遇到的相关限制的方程,以及LD电流与某种形式的电流增益转换因子的关系,根据增益曲线上的最佳工作点来优化有源区量子阱数目.给出了共面量子阱LD在固定有源长度、固定无源区长度的共面量子阱激光器的量子阱数目优化方案.  相似文献   

5.
自适应微摩擦综合测试仪的研制与纳米润滑实验研究   总被引:9,自引:0,他引:9  
描述了作者研制的自适应微摩擦综合测试仪的基本原理。采用多用途自适应浮动结构、精密刀口杠杆加载结构和摩擦力精密测量系统,可精确地加载和测量mN量级的摩擦力。研究纳米膜在各种润滑方式下的摩擦学性能,同时采用相对光强光干涉法,检测纳米级的润滑膜厚以及润滑状态的变化。以10#标准粘度液作润滑剂,分别用面接触浮动润滑副和点接触浮动润滑副作实验,研究了其摩擦因数和润滑膜厚度随载荷、速度和运动方式(点接触纯滑动和纯滚动)的变化规律,并验证了仪器的实验性能。  相似文献   

6.
Twenty-nine species (24 genera, 6 families) of butterflies typical and common in northeast China were selected to make qualitative and quantitative studies on the pattern, hydrophobicity and hydrophobicity mechanism by means of scanning electron microscopy and contact angle measuring system. The scale surface is composed of submicro-class vertical gibbosities and horizontal links. The distance of scale is 48—91 μm, length 65—150 μm, and width 35—70 μm. The distance of submicro-class vertical gib-bosities on scale is 1.06—2.74 μm, height 200—900 nm, and width 200—840 nm. The better hydropho-bicity on the surface of butterfly wing (static contact angle 136.3°—156.6°) is contributed to the co-effects of micro-class scale and submicro-class vertical gibbosities on the wing surface. The Cassie equation was revised, and new mathematical models and equations were established.  相似文献   

7.
In this paper, we propose a new en-/de-coding scheme of spreading time OCDMA utilizing the dispersion of grating and filter in frequency domain. The key components of the scheme are grating pair, Fourier transformation lens, phase filter etc. The results of design and calculation are shown that the spreading time of input pulse can be up to nanosecond-duration and the phase filter can provide pseudo-noise bursts in time domain. The requirements for Laser and optical detection equipment in the scheme are reduced. So the new scheme proposed by us is effective for OCDMA en-/de-coding of coherent ultra-short pulses.  相似文献   

8.
In this paper, we propose a new en-/de-coding scheme of spreading time OCDMA utilizing the dispersion of grating and filter in frequency domain. The key components of the scheme are grating pair, Fourier transformation lens, phase filter etc. The results of design and calculation are shown that the spreading time of input pulse can be up to nanosecond-duration and the phase filter can provide pseudo-noise bursts in time domain. The requirements for Laser and optical detection equipment in the scheme are reduced. So the new scheme proposed by us is effective for OCDMA en-/de-coding of coherent ultra-short pulses.  相似文献   

9.
采用平凹腔,实现LD端面泵浦Nd∶YAG/LBO全固态蓝光激光器.在泵光功率为7.33W时,得到最大蓝光输出87.6mW,倍频光转换效率为1.2%,斜效率为2.6%.通过求解Possion热传导方程,得出了Nd∶YAG内部温度场分布.  相似文献   

10.
激光防护材料近况   总被引:1,自引:0,他引:1  
按照防护原理,可将激光防护材料分为基于线性光学理论的防护材料和基于非线性光学理论的防护材料.综述了基于线性和非线性光学理论的激光防护方法和原理.介绍了多种激光防护材料及其研究进展,并简要分析了两类激光防护技术的优缺点和今后的发展趋势。  相似文献   

11.
A family of binary sequences were constructed by using an elliptic curve and its twisted curves over finite fields. It was shown that these sequences possess "good" cryptographie properties of 0-1 distribution, long period and large linear complexity. The results indicate that such se quences provide strong potential applications in cryptography.  相似文献   

12.
According to the principle, “The failure data is the basis of software reliability analysis”, we built a software reliability expert system (SRES) by adopting the artificial intelligence technology. By reasoning out the conclusion from the fitting results of failure data of a software project, the SRES can recommend users “the most suitable model” as a software reliability measurement model. We believe that the SRES can overcome the inconsistency in applications of software reliability models well. We report investigation results of singularity and parameter estimation methods of experimental models in SRES. Foundation item: Supported by the National Natural Science Foundation of China Biography: XU Ren-zuo (1946-), male, Professor, research interests include software engineering software reliability engineering, software quality guarantee technology, reliability theory, software safety and security.  相似文献   

13.
分析了极大似然估计算法中测距误差对定位误差的影响,提出了基于LMS(最小均方差)的自适应滤波原理的测距误差修正的自定位算法. 利用极大似然估计法初步估计节点位置,并得到定位误差信息,建立测距误差矩阵并更新网络中的滤波参数,完成对网络中测距误差的抑制,从而优化节点定信息. 实验仿真表明,优化处理使定位精度得到提高. 结果表明算法适用于锚节点密度较小的、低信噪比的网络化弹药系统.  相似文献   

14.
在激光扫描测试系统的研制过程中发现,扫描电机转速波动是导致测试精度难以提高的主要原因。在实验研究的基础上,通过分析扫描电机的转动特性,提出了一种实时补偿电机转速变化的有效方法,实际应用表明该方法不仅能使测量精度提高一个数量级,而且大大简化了系统的硬件结构。  相似文献   

15.
A novel hybrid instrument of contact and non-contact measurement with large range is developed, and both measurement systems are based on a Linnik interference microscope and on white-light interference measuring techniques. The ambiguity presented in conventional monochromatic interferometers is not present in the contact and non-contact measurement, and they have a virtually unlimited unambiguous range. For the contact measurement, the vertical measuring range is ±5 mm with a resolution of 1 nm and the horizontal measuring range is ±25 mm in x-range and y-range with a resolution of 1.25 μm; for the non-contact measurement, the vertical measuring range is ~5 mm with a resolution of 1 nm and the horizontal resolution better than 0.5 urn.  相似文献   

16.
Various methods for precise orbit determination (POD) of low earth orbiters (LEO) are briefly intro-duced in this paper. Based on the software named SHORD-Ⅲ developed by our institute,sin-gle-difference (SD) and zero-difference (ZD) dynamic POD based on LEO carrying an on-board GPS receiver is mainly discussed. The approaches are tested using real GRACE data (November 5―25,2002) and independently validated with Satellite Laser Ranging (SLR) measurements over the same 21 days. Comparisons with the scientific orbits provided by GFZ indicate that the SD POD RMS accuracy can achieve 5,10 and 6 cm in radial,along and cross the track,and the ZD POD RMS accuracy can achieve 4,8 and 4 cm in radial,along and cross the track. SLR validation shows that SD POD accuracy is better than 8 cm in distance,and ZD POD accuracy is better than 6 cm.  相似文献   

17.
18.
According to the principle, “The failure data is the basis of software reliabilityanalysis”, we built a software reliability expert system (SRES) by adopting the artificialtechnology. By reasoning out the conclusion from the fitting results of failure data of asoftware project, the SRES can recommend users “the most suitable model” as a softwarereliability measurement model. We believe that the SRES can overcome the inconsistency inapplications of software reliability models well. We report investigation results of singularity and parameter estimation methods of models, LVLM and LVQM. Foundation item: Supported by the National Natural Science Foundation of China Biography: Biography: XU Ren-zuo (1946-), male, Professor, Research interests include software engineering, software reliability engineering, software quality guarantee technology, reliability theory, software safety and security.  相似文献   

19.
Inclusion reaction of racemic 1,1′-bi-2-naphthol and (S)-proline was examined under the solid state and the solid-liquid conditions. The results indicated that a solid mixture of racemic 1,1′-bi-2-naphthol and (S)-proline in a 1∶1 molar ratio was kept at 50–80 °C for 3–4 h, followed by treatment with benzene to give an insoluble solid and a benzene solution, from which (S)-(−)- and (R)-(+)-1,1′-bi-2-naphthols of a modest level of optical purity were obtained. After “kinetic” crystallization, both essentially enantiopure isomers were provided in 15%–35% overall yields, respectively. Foundation item: Supported by the National Natural Science Foundation of China (29972033) and the Key Science Research Foundation of Hubei Province (891P1305) Biography: Shan Zi-xing (1945-), male, Professor, research direction: asymmetric synthesis.  相似文献   

20.
汽车测速、测距的防撞预警可有效避免交通事故的发生。介绍了测速、测距原理,在此基础上论述了基于系统及芯片(system on a chip,SoC)的汽车防撞系统,提出了一种应用SoC芯片和超宽带(ultra wide band,UWB)无线定位技术的汽车防撞系统方案,研究了系统中关键功能模块UWB模块和SoC信号处理模块的实现和软件处理流程。结果表明,该方案可对行驶中的汽车与汽车以及汽车与其他障碍物之间的距离进行实时监测,在距离较近时能准确及时地判断并采取合理的处理措施,避免碰撞的发生,保障行车安全。  相似文献   

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