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Anti-Stokes Line in an Index-Guiding Photonic Crystal Fibre with Two Zero-Dispersion Wavelengths

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Chinese Physics Letters 2008年第6期25卷 2055-2057页

作者：王伟高飞侯蓝田周桂耀 Institute of Infrared Optical Fibers and Sensors Yanshan University Qinhuangdao 066004 Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao 066004

An index-guiding photonic crystal fibre with a small hole in the core is fabricated. The simulated results show that the first higher order mode possesses two zero-dispersion wavelengths, and the phase-matching is possible in the anomalous dispersion regime between the two zero-dispersion wavelengths. Using 200 fs Ti： sapphire laser of 820, 830 and 840nm, the anti-Stokes line around 530nm can be generated efficiently. The maximum ratio of the anti-Stokes signal energy to the pump component in the output spectrum is estimated to be 1.03 and the conversion efficiency is above 50%.

关键词： MICROSTRUCTURED OPTICAL-FIBERS MULTIPOLE METHOD HOLEY FIBERS GENERATION efficient

Power of all-fiber amplifier increasing from 1030 W to 2280 W through suppressing mode instability by increasing the seed power

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Chinese Physics B 2019年第2期28卷 252-256页

作者： Xue-Xue Luo Ru-Mao Tao Chen Shi Han-Wei Zhang Xiao-Lin Wang Pu Zhou Xiao-Jun Xu College of Advanced Interdisciplinary Studies National University of Defense Technology Hunan Provincial Key Laboratory of High Energy Laser Technology National University of Defense Technology Hunan Provincial Collaborative Innovation Center of High Power Fiber Laser

In this work, we investigate suppressing mode instability in detail by varying the seed power in a large mode area all-fiber amplifier with a fiber core diameter of 25 μm. The transverse mode instability(TMI) thresholds are systematically measured for different seed power. Our experimental results reveal that increasing the seed power has a positive influence on enhancing the output power before the TMI effect appears, and finally the TMI threshold is approximately doubled from1030 W to 2280 W when the seed power is increased from 27 W to 875 W. Almost 84.7% slope efficiency is reached with different seed power before the TMI threshold power. During our operation, we also find that in this type of LMA fiber the beam quality of the amplifier is degraded gradually instead of a sudden change as the pump power increases.

关键词： mode instabilities seed power coupling efficient beam quality degradation

Optimization of a magneto–optic trap using nanofibers

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Chinese Physics B 2019年第7期28卷 198-201页

作者： Xin Wang Li-Jun Song Chen-Xi Wang Peng-Fei Zhang Gang Li Tian-Cai Zhang State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Opto-Electronics Shanxi University Taiyuan 030006 China Collaborative Innovation Center of Extreme Optics Shanxi University Taiyuan 030006 China

We experimentally demonstrate a reliable method based on a nanofiber to optimize the number of cold atoms in a magneto–optical trap(MOT) and to monitor the MOT in real *** atomic fluorescence is collected by a nanofiber with subwavelength diameter of about 400 *** MOT parameters are experimentally adjusted in order to match the maximum number of cold atoms provided by the fluorescence collected by the *** maximum number of cold atoms is obtained when the intensities of the cooling and re-pumping beams are about 23.5 mW/cm^2 and 7.1 mW/cm^2,respectively;the detuning of the cooling beam is-13.0 MHz, and the axial magnetic gradient is about 9.7 Gauss/*** observe a maximum photon counting rate of nearly(4.5 ± 0.1)× 10^5 counts/*** nanofiber–atom system can provide a powerful and flexible tool for sensitive atom detection and for monitoring atom–matter *** can be widely used from quantum optics to quantum precision measurement.

关键词： nanofiber magneto–optic trap optimization fluorescence efficient coupling

A Q-Swicthed All-Solid-State Single-Longitudinal-Mode Laser with Adjustable Pulse-Width and High Repetition Rate

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Chinese Physics Letters 2006年第1期23卷 129-131页

作者：周军许世忠侯霞韦辉陈卫标 Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800

A single-longitudinal-mode （SLM） laser-diode pumped Nd： YAG laser with adjustable pulse width is developed by using the techniques of pre-lasing and changing polarization of birefingent crystal The Q-switching voltage is triggered by the peak of the pre-lasing pulse to achieve the higher stability of output pulse energy. The output energy of more than I mJ is obtained with output energy stability of 3% （rms） at lOO Hz. The pulsewidth can be adjusted from 30ns to 300ns by changing the Q-switching voltage. The probability of putting out single-longitudinal-mode pulses is almost 100%. The laser can be run over four hours continually without mode hopping.

关键词： ND-YAG LASER Q-SWITCHED LASER efficient OPERATION

Facile Fabrication of Fe2O3/Nitrogen Deficient g-C3N4-x Composite Catalysts with Enhanced Photocatalytic Performances

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Journal of Wuhan University of Technology(Materials Science) 2019年第5期34卷 1018-1023页

作者： LIU Qi ZHANG Yi XIA Shibin School of Resources and Environmental Engineering Wuhan University of TechnologyWuhan 430070China State Key Laboratory of Freshwater Ecology and Biotechnology Institute of HydrobiologyChinese Academy of SciencesWuhan 430072China

The modification of graphitic carbon nitride can significantly improve the photocatalytic performance of graphitic carbon nitride(g-C3N4).Fe2O3/nitrogen-deficient g-C3N4-x composite catalysts were prepared with dicyandiamide as the precursor and Fe3+doped in this *** composite catalysts were characterized by XRD,SEM,FT-IR,XPS and photocurrent *** interaction occurred between Fe2O3 and nitrogen deficient g-C3N4-x,more photogenerated electrons were created and effectively separated from the holes,resulting in a decrease of photocarrier recombination,and thus enhancing the *** performance experiments showed that Fe2O3/nitrogen deficient g-C3N4-x could utilize lowenergy visible light more efficiently than pure g-C3N4,and the removal rate was 92%in 60 minutes.

关键词： Fe2O3/nitrogen deficient g-C3N4-x characterization carbon materials heterojunction efficient photocatalytic activity

THE CHARACTERIZATION OF EFFICIENCY AND SADDLE POINT CRITERIA FOR MULTIOBJECTIVE OPTIMIZATION PROBLEM WITH VANISHING CONSTRAINTS

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Acta Mathematica Scientia 2019年第2期39卷 382-394页

作者： Anurag JAYSWAL Vivek SINGH Department of Applied Mathematics Indian Institute of Technology (Indian School of Mines)

In this article, we focus to study about modified objective function approach for multiobjective optimization problem with vanishing constraints. An equivalent η-approximated multiobjective optimization problem is constructed by a modification of the objective function in the original considered optimization problem. Furthermore, we discuss saddle point criteria for the aforesaid problem. Moreover, we present some examples to verify the established results.

关键词： multiobjective optimization problem with vanishing constraints efficient solution invexity η-Lagrange function saddle point

The necessary and sufficient conditions for returns to scale properties in generalized data envelopment analysis model

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Science China(Technological Sciences) 2002年第5期45卷 503-517页

作者：魏权龄于刚陆剑受 Institute of Operations Research and Mathematical Economics People's University of China Beijing 100872 China Department of MSIS Graduate School of Business and Center for Management of Operations and LogisticsUniversity of Texas at Austin Austin TX 78712 U.S.A. Department of Economics Guangxi University Nanning 530004 China

We give definitions on increasing, constant and decreasing returns to scale under the generalized data envelopment analysis (GDEA) model. The GDEA model prossesses cone structures for describing evaluators’ preferences toward different decision making units (DMU) and toward different input / output categories. The GDEA model contains many important DEA models as its subclasses. Based upon the definition, we discuss and rigorously prove the necessary and sufficient conditions for a DMU to have increasing, constant and decreasing returns to scale under a GDEA model, and discuss and clarify the differences and relationships of these conditions under different subclasses of the GDEA model. Furthermore, we describe a method based on a two-stage linear program to test returns to scale properties.

关键词： data envelopment analysis, efficient frontier, multiple input/output decision making,production possibility set, returns to scale.

Synthesis of a Novel Carbon Based Acid Catalyst and Its Catalytic Activity for the Acetalization and Ketalization

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Chinese Journal of Chemistry 2007年第12期25卷 1795-1797页

作者：梁学正高珊程文萍王雯娟杨建国 Shanghai Key Laboratory of Green Chemistry and Chemical Process East China Normal University Shanghai 200062 China

A novel carbon based strong solid acid catalyst has been synthesized successfully. The catalytic activity for acetalization and ketalization was investigated. The results showed that the novel catalyst was very efficient with the average yield over 92%. The novel heterogeneous catalyst also has the advantages of high activity, wide applicability even to the preparation of 7 membered ring acetals and ketals, strikingly simple workup procedure, non-pollution and reusability, which will contribute to the green process greatly.

关键词： novel carbon based catalyst acetal ketal catalyst efficient

Efficiency and superefficiency in one-parameter two-sided truncated distribution families

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Chinese Science Bulletin 1997年第21期42卷 1771-1774页

作者： James C. Fu Department of Statistics University of Manitoba Winnipeg R3T 2N2 Canada

whereθis an unknown parameter, φ(θ) is a continuous differentiable function such that θ0, θ∈R, and f(x;θ) is a positive continuous density func-tion on [θ,φ(θ)]. The one-parameter two-sided truncated distrib... 详细信息

关键词： one-parameter two-sided truncated family super-efficiency a new efficiency asymptotically median unbiased efficient estimate.