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41.
激光二极管泵浦的高效、单频Nd:YVO4激光器   总被引:2,自引:0,他引:2  
对激光二极管端面泵浦的单频Nd:YVO4激光器进行了研究,研究了不同输出耦合率情况下输出功率随泵浦功率的变化曲线及光-光转化效率随输出耦合率的变化曲线,实验结果与理论分析结果基本一致.当泵浦功率为2.2 W时,得到瓦级单频1064 nm激光输出,最高光-光转化效率为47.2%.  相似文献   
42.
含稀土抗蠕变压铸镁合金的开发   总被引:5,自引:0,他引:5  
针对商用压铸镁合金抗高温蠕变性能较差的现状,开发了抗高温蠕变压铸镁合金,其开发的目的是针对大马力柴油发动机汽缸罩盖,其抗高温蠕变性能应该能够保障其在150℃条件下稳定工作,而且其成本的增加应该控制在AZ91D合金成本的15%以内。讨论了稀土元素Ce,Y,Nd及Ca和Si的添加对压铸镁合金在常温拉伸性能以150℃条件下的蠕变行为、显微组织的影响,以及对表面处理和腐蚀试验的影响,并进行了实际产品的压铸牛产。试验结果表明,所开发的抗蠕变压铸镁合金具有应用于汽车动力系统部件的制造并大幅度减轻重量的潜力。  相似文献   
43.
刘忠  邱耀辉  楼柯  卢汝为 《光学学报》2002,22(3):76-280
在天文班点成像技术中,Hofmann等提出的迭代最小二乘法--积木法,能避免在由被观测目标像的重谱复原相位谱时复杂的相位递推过程,因此相误差的传递和积累也被消除了,但在该方法中,存在着新的问题;需要大量投放木块的迭代次数和长时间的处理过程,为提高该方法的工作效率,用“迭代位移叠加法”对目标斑点图进行预处理,经少数几次位移叠加的步骤后,很快就提供了目标像的基本结构和分布,得到了积木块投放点的位置,从而避免了盲目投放,大大减少了迭代投放的次数,显著地提高了该方法的效率。  相似文献   
44.
Xu  Lei  Li  Yaohui  Mu  Yuanchun  Chen  Wei  Zhang  Fan  Wang  Jinzhen  Zu  Chenkui 《Journal of Sol-Gel Science and Technology》2021,99(2):413-419
Journal of Sol-Gel Science and Technology - The silica sol and potassium hydroxide solution are mixed under certain conditions to form a precursor solution, which is poured into a closed cavity and...  相似文献   
45.
We demonstrate a 7-bit photonic true-time-delay (TTD) system which uses an 8 × 8 micro-optical-electro- mechanical system (MOEMS) optical switch for phased array antennas (PAAs) beamforming applications. The switch controls the optical signal to pass by the fiber delay lines (FDLs) of different lengths. Different time delays between adjacent channels are obtained due to the chromatic dispersion of FDLs. Therefore, the system cannot be disturbed by the environment. The measured time delay responses are nearly linear with the wavelength spacing between optical carriers as well as the lengths of FDLs, which agrees well with the theoretical analysis.  相似文献   
46.
Anomalous diffusion is researched within the framework of the coupled continuous time random walk model, in which the space-time coupling is considered through the correlated function g(t) ~ t γ , 0 ≤ γ< 2, and the probability density function ω(t) of a particle’s transition time t follows a power law for large t: ω(t) ~ t ? (1 + α),1 <α< 2. The bi-fractional generalized master equation is derived analytically which can be applied to describe the transient bi-fractional diffusion phenomenon which is induced by the space-time coupling and the asymptotic behavior of ω(t). Numerical results show that for the transient bi-fractional diffusion, there is a transition from one fractional diffusion to another one in the diffusive process.  相似文献   
47.
蛋白质糖基化是生物体中最重要的翻译后修饰手段之一,糖蛋白/糖肽的有效分离和富集成为目前糖蛋白组学研究的首要问题.对于复杂的生物样本,糖蛋白的数量较少,酶解后大量高丰度非糖基化修饰肽的存在,使得低丰度糖肽的检测更加困难.因此,需要一些手段来有效地富集糖肽以提高其检测丰度,发展高选择性的糖肽富集材料及方法就成为在分子水平上...  相似文献   
48.
天文像复原迭代位移叠加法中的噪声偏差补偿   总被引:1,自引:1,他引:0  
邱耀辉  刘忠  卢汝为  楼柯 《光学学报》2002,22(7):29-833
当工作于实际数据时,由于存在着多种噪声,导致了天文像复原迭代位移叠加法中的噪声偏差项,为消除这些噪声偏差项的影响,分别讨论了在观测目标和参考星的斑点数据期间由大气视宁度差异引入的系统误差和探测器严重的附加噪声产生的偏差,并给出了对这些噪声偏差项的补偿方法。  相似文献   
49.
Color-tunable dual-mode organic afterglow excited by ultraviolet (UV) and white light was achieved from classical aggregation-caused quenching compounds for the first time. Specifically, two luminescent systems, which could produce significant organic afterglow composed of persistent thermally activated delayed fluorescence and ultralong organic phosphorescence under ambient conditions, were constructed by doping fluorescein sodium and calcein sodium into aluminum sulfate. Their lifetimes surpassed 600 ms, and the dopant concentrations were as low as 5×10−6 wt %. Moreover, the persistent luminescence colors of the materials could be tuned from blue to green and then to yellow by simply varying the concentrations of guest compounds or the temperature in the range of 260–340 K. Inspired by these exciting results, the afterglow materials were used for UV- and white-light-manipulated anti-counterfeiting and preparation of elastomers with different colors of persistent luminescence.  相似文献   
50.
The protein phenotypes of extracellular vesicles (EVs) have emerged as promising biomarkers for cancer diagnosis and treatment monitoring. However, the technical challenges in rapid isolation and multiplexed molecular detection of EVs have limited their clinical practice. Herein, we developed a magnetically driven tandem chip to achieve streamlined rapid isolation and multiplexed profiling of surface protein biomarkers of EVs. Driven by magnetic force, the magnetic nanomixers not only act as tiny stir bars to promote mass transfer and enhance reaction efficiency of EVs, but also transport on communicating vessels of the tandem chip continuously and expedite the assay workflow. We designed cyclic surface enhancement of Raman scattering (SERS) tags to bind with target EVs and then release them by exonuclease I, eliminating steric hindrance and amplifying the SERS signal of multiple protein biomarkers on EVs. Due to the excellent assay performance, six breast cancer biomarkers were detected simultaneously on EVs using only 10 μL plasma within 1.5 h. The unweighted SUM signature offers great accuracy in discriminating breast cancer patients from healthy donors. Overall, the dynamic magnetic driving tandem chip offers a new avenue to advance the clinical application of EV-based liquid biopsy.  相似文献   
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