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光折变的光学脉动现象及其非线性过程 被引量:1
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作者 武原庆 许京军 +1 位作者 刘思敏 张光寅 《红外与毫米波学报》 SCIE EI CAS CSCD 北大核心 1991年第1期11-16,共6页
报道了光折变LiNbO_3:Fe晶体中双光束耦合和四波混频的脉动现象。认为这种脉动现象起因于LiNbO_3:Fe晶体中的陷阱重复荷电波在光折变材料中感应出的运动折射率光栅。
关键词 铌酸锂 光学脉动 光折变 非线性
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光学脉动进位多比特全加(减)器 被引量:1
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作者 周少敏 金国藩 邬敏贤 《应用激光联刊》 CSCD 北大核心 1989年第4期181-184,共4页
本文提出了一种利用光学符号代换法则和脉动进位原理实现进位超前的光学多比特全加(减)器,其特点是不需要任何实时器件来存储中间结果,所以结构简单、速度快,并且可以实现由多比特二进制数所组成的矩阵间的加(减)法。
关键词 全加器 全减器 光学脉动 光学符号
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A meta-analysis for assessing the value of MR spectroscopy in the diagnosis of prostate cancer
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作者 强永乾 郭佑民 +3 位作者 王鹏 郭晓娟 陈敏 刘敏 《Journal of Medical Colleges of PLA(China)》 CAS 2006年第6期401-407,共7页
Objective: To assess the value of MR spectroscopy (MRS) in the diagnosis of prostate cancer by meta-analysis. Methods: Prospective studies were selected from the MEDLINE, Ovid, Embase databases, Springer, Elsevier... Objective: To assess the value of MR spectroscopy (MRS) in the diagnosis of prostate cancer by meta-analysis. Methods: Prospective studies were selected from the MEDLINE, Ovid, Embase databases, Springer, Elsevier, China National Knowledge Infrastructure. According to the suggestion, results were determined by the ratio of (Cho+Cr)/Cit. If this ratio was less than 0.75, negative result was respectively determined, and the definitive tumor was diagnosed as this threshold. According to the assessment standard of Evidence-based Medicine, English and Chinese literature in Grade A and B on MRS imaging was included. According to homogeneity test, different effect models were chosen to calculate different pooled weighted values of sensitivity, specificity and the corresponding 95% confidence intervals (95% CI). Summary receiver operating characteristic (SROC) curves were used to assess the results. Funnel plot was used to analyze publication bias. Results: According to the assessment standard of Evidence-based Medicine, only 5 papers in Grade B were included in this research. The pooled weighted sensitivity and its 95% confidence interval is 82% (73%, 89%) and the pooled weighted sensitivity and its 95% confidence interval is 68% (58%, 76%). The AUC (area under curve) is 83.40%. An asymmetric funnel plot suggested two missing studies leading to publication bias. Conclusion: If the ratio of (Cho+Cr)/Cit is regarded as the diagnostic criteria in detecting prostate cancer by MRS, meta-analysis suggests this method has a better diagnostic value to detect the malignant prostate mass but the sensitivity needs to be improved. We hope to support a method and requirement about diagnostic test. Performing perspective register and improving quality of study design is the only way to reduce the bias and get real information of disease. 展开更多
关键词 META-ANALYSIS prostate carcinoma magnetic resonance spectroscopy summary receiver operating characteristic curve
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Impact of substrate on opto-thermal response of thin metallic targets under irradiation with femtosecond laser pulses
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作者 TSIBIDIS G D STRATAKIS E 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第10期3410-3421,共12页
Femtosecond pulsed lasers have been widely used over the past decades due to their capability to fabricate precise patterns at the micro-and nano-lengths scales. A key issue for efficient material processing is the de... Femtosecond pulsed lasers have been widely used over the past decades due to their capability to fabricate precise patterns at the micro-and nano-lengths scales. A key issue for efficient material processing is the determination of the laser parameters used in the experimental set ups. Despite a systematic investigation that has been performed to highlight the impact of every parameter independently, little attention has been drawn on the role of the substrate material on which the irradiated solid is placed. In this work, the influence of the substrate is emphasised for films of various thicknesses, which demonstrates that both the optical and thermophysical properties of the substrate affect the thermal fingerprint on the irradiated film while the impact is manifested to be higher at smaller film sizes. Two representative materials, silicon and fused silica, have been selected as typical substrates for thin films(gold and nickel) of different optical and thermophysical behaviour and the thermal response and damage thresholds are evaluated for the irradiated solids. The pronounced influence of the substrate is aimed to pave the way for new and more optimised designs of laserbased fabrication set ups and processing schemes. 展开更多
关键词 femtosecond laser pulse ultrafast dynamics optical excitation two-temperature model
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Microscopic Dynamics of Nonsequential Double Ionization by Elliptically Polarized Few-Cycle Laser Pulses 被引量:1
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作者 余本海 李盈傧 李方涛 《Communications in Theoretical Physics》 SCIE CAS CSCD 2013年第6期714-718,共5页
With the classical ensemble model, we investigate nonsequential double ionization (NSDI) of xenon atoms using 780 nm, 0.25 PW/cm2 elliptically polarized few-cycle laser pulses. The momentum distribution of correlate... With the classical ensemble model, we investigate nonsequential double ionization (NSDI) of xenon atoms using 780 nm, 0.25 PW/cm2 elliptically polarized few-cycle laser pulses. The momentum distribution of correlated electron along the long axis o~ the laser polarization plane shows an obvious V-like structure locating at the third quadrant, and the momentum along the short axis of the laser polarization plane are mainly distributed in the second and fourth quadrants. Moreover, we demonstrate that the Coulomb repulsion interaction plays a decisive role to the above results. By back analyzing the class/ca/ trajectories of NSDI, we find that there are two kinds of recollision trajectories mainly contribute to NSDI, and the different microscopic dynamics for the two kinds of trajectories are clearly explored. 展开更多
关键词 rnonsequential double ionization elliptically few-cycle laser pulse recollision time delay
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Rogue Waves of the Higher-Order Dispersive Nonlinear Schrdinger Equation 被引量:1
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作者 王晓丽 张卫国 +1 位作者 翟保国 张海强 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第10期531-538,共8页
In this paper,the rogue waves of the higher-order dispersive nonlinear Schrdinger(HDNLS) equation are investigated,which describes the propagation of ultrashort optical pulse in optical fibers.The rogue wave solutions... In this paper,the rogue waves of the higher-order dispersive nonlinear Schrdinger(HDNLS) equation are investigated,which describes the propagation of ultrashort optical pulse in optical fibers.The rogue wave solutions of HDNLS equation are constructed by using the modified Darboux transformation method.The explicit first and secondorder rogue wave solutions are presented under the plane wave seeding solution background.The nonlinear dynamics and properties of rogue waves are discussed by analyzing the obtained rational solutions.The influence of little perturbation on the rogue waves is discussed with the help of graphical simulation. 展开更多
关键词 rogue wave higher-order dispersive nonlinear Schrodinger equation modified Darboux transformation
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THE DYNAMICAL BEHAVIOR OF NON-SMOOTH SYSTEM WITH IMPULSIVE CONTROL STRATEGIES 被引量:1
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作者 YUAN-SHUN TAN JU-HUA LIANG SAN-YI TANG 《International Journal of Biomathematics》 2012年第3期297-313,共17页
Non-smooth system including impulsive strategies at both fixed and unfixed times are analyzed. For the model with fixed impulsive effects, the global stability of pest eradi- cation periodic solution and the dominance... Non-smooth system including impulsive strategies at both fixed and unfixed times are analyzed. For the model with fixed impulsive effects, the global stability of pest eradi- cation periodic solution and the dominance of dynamic behavior are investigated. This indicates that the model with fixed moments has the potential to protect the natural enemies from extinction, but under some conditions may also serve to extinction of the pest. The second model is constructed according to the practices of IPM, that is, when the pest population reaches the economic injury level, a combination of biological, cultural, and chemical tactics that reduce pests to tolerable levels is used. Numerical investigations imply that there are several different types of periodic solutions and their maximum amplitudes are always less than the given economic threshold. The results also show that the time series at which the IPM strategies are applied are quite complex, which means that the application and realization of IPM in practice are very difficult. 展开更多
关键词 DOMINANCE non-smooth system impulsive control strategies integrated pest management global stability.
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