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Highly Efficient Self-Starting Femtosecond Cr：Forsterite laser

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Chinese Physics Letters 2008年第10期25卷 3679-3681页

作者：周斌斌张永东钟欣魏志义 Laboratory of Optical Physics Institute of Physics Chinese Academy of Sciences Beijing 100190

We report a highly efficient and high power self-starting femtosecond Cr：forsterite laser pumped by a 1064-nm Yb doped fibre laser. Five chirped mirrors are used to compensate for the intra-cavity group-delay dispersion, and the mode-locking is initiated by a semiconductor saturable absorber mirror （SESAM）. Under pump power of 7.9 W, stable femtosecond laser pulses with average power of 760mW are obtained, yielding a pump power slope efficiency of 12.3%. The measured pulse duration and spectral bandwidth （FWHM） are 46 fs and 45 nm; the repetition rate is 82 MHz.

关键词： the power-law exponents precipitation durative abrupt precipitation change

SbOx Thin Films Used for Write-Once Blue laser Recording

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Chinese Physics Letters 2007年第5期24卷 1287-1289页

作者：周莹耿永友顾冬红朱青 Shanghai institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800

SbOx thin films are deposited by reactive dc-magnetron sputtering from an antimony metal target in Ar＋O2 with the relative O2 content 7%. It is found that the as-deposited films can represent a two-component system comprising amorphous Sb and amorphous Sb2 O3. The crystallization of Sb is responsible for the changes of optical properties of the films. The results of the static test show that the SbOx thin films have good writing sensitivity for blue laser beams and the recording marks are very clear and circular. High reflectivity contrast of about 41% is obtained at a writing power 6mW and writing pulse width 300ns. In addition, the films show a good stability after reading 10000 times.

关键词： OPTICAL-STORAGE

Analysis of directional emission in square resonator lasers with an output waveguide

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Chinese Optics Letters 2007年第8期5卷 463-465页

作者：赵伟黄永箴 State Key Laboratory on Integrated Optoelectronics institute of Semiconductors Chinese Academy of Sciences

Square microcavity laser with an output waveguide is proposed and analyzed by the finite-difference time-domain （FDTD） technique. For a square resonator with refractive index of 3.2, side length of 4μm, and output waveguide of 0.4μm width, we have got the quality factors （Q factors） of 6.7 ×10^2 and 7.3 × 10^3 for the fundamental and first-order transverse magnetic （TM） mode near the wavelength of 1.5μm, respectively. The simulated intensity distribution for the first-order TM mode shows that the coupling efficiency in the waveguide reaches 53%. The numerical simulation shows that the first-order transverse modes have fairly high Q factor and high coupling efficiency to the output waveguide. Therefore the square resonator with an output waveguide is a promising candidate to realize single-mode directional emission microcavity lasers.

关键词： Computer simulation Finite difference time domain method laser modes Light emission Refractive index

Asphaltenes: Separations, structural analysis and applications

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Journal of Energy Chemistry 2019年第7期28卷 186-207页

作者： Pingping Zuo Shijie Qu Wenzhong Shen State Key Laboratory of Coal Conversion Institute of Coal Chemistry Chinese Academy of Sciences

Asphaltenes, complex aromatic compounds from various carbonaceous sources, could be obtained by solvent dissolution, filtration and adsorption. It was difficult to clarify the molecular structures and chemical properties of asphaltene due to its structural similarity, composition complexity and source dependences. Many techniques, like Mass spectrometry, Chromatography, Nuclear magnetic resonance spectroscopy, Infrared spectroscopy, Roman spectroscopy, Fluorescence spectroscopy, X-ray diffraction analysis and Small-angle scattering techniques and so on, have revealed some valuable descriptions of asphaltenes chemical compositions and fundamental structures. Moreover, advanced Mass spectrometry,Atomic force microscopy and Scanning tunneling microscopy could provide more clear and essential molecular compounds and structures in asphaltenes. In addition, several asphaltenes models have succeeded to illustrate aggregation properties asphaltene. In this work, the progress on asphaltene separation, characterization and application was summarized, and the similarities and differences between coal-derived asphaltenes and petroleum asphaltenes were compared. Furthermore, the reactivity of asphaltenes has been discussed in the aspect of hydroprocessing, pyrolysis and gasification. Asphaltene was excellent carbon precursor for functional carbon material due to its high aromaticity and carbon yield;several porous carbon nanosheets from asphaltenes that would be prospective electrode materials after being graphitized were shown. Pitch-based carbon fiber derived from coal-derived asphaltenes displayed a tensile strength of 1.0 GPa and elastic modulus of 350 MPa, respectively. These powerful advances will provide asphaltenes promising developments.

关键词： Asphaltenes Separations Structures Aggregation Applications

The Molecular Structure of SEBS Grafted with Maleic Anhydride through Ultrasound Initiation

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Chinese Journal of Polymer Science 2015年第7期33卷 988-999页

作者： Xian-long Zhang 吴宏郭少云 The State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan University

The molecular structure of SEBS grafted with maleic anhydride（SEBS-g-MAH） through ultrasound initiation was investigated by nuclear magnetic resonance（NMR）. It can be confirmed that the grafting groups mainly exist on the terminus of the ultrasound initiated SEBS-g-MAH. However, it was difficult to detailedly confirm the block of the SEBS on which MAH is grafted through characterization of 1H-NMR due to the complex structure of the SEBS. Moreover, the temperaturedependent infrared spectra of the ultrasound initiated SEBS-g-MAH were also analyzed by the perturbation correlation moving window 2D（PCMW2D） correlation spectroscopy. It could confirm that the broken point existed at the joint between poly（ethylene-co-1-butene）（EB block） and polystyrene block（S block）. Therefore, the grafting groups were attached to not only the S block but also the EB block. In addition, in order to well understand the aggregation structure of the ultrasound initiated SEBS-g-MAH, the possible grafting mechanism and aggregation model of the ultrasound initiated SEBS-g-MAH at room temperature were also proposed.

关键词： Ultrasound Molecular structure SEBS-g-MAH Grafting

New design of a compact aero-robotic drilling end effector: An experimental analysis

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Chinese Journal of Aeronautics 2016年第4期29卷 1132-1141页

作者： Shi Zhenyun Yuan Peijiang Wang Qishen Chen Dongdong Wang Tianmiao School of Mechanical Engineering and Automation Beihang University Beijing institute of Aerospace Control Devices

This paper presents the development of a normal adjustment cell (NAC) in aero-robotic drilling to improve the quality of vertical drilling, by using an intelligent double-eccentric disk normal adjustment mechanism (2-EDNA), a spherical plain bearing and a floating compress module with sensors. After the surface normal vector is calculated based on the laser sensors' feedback, the 2-EDNA concept is conceived specifically to address the deviation of the spindle from the surface normal at the drilling point. Following the angle calculation, depending on the actual initial position, two precise eccentric disks (PEDs) with an identical eccentric radius are used to rotate with the appropriate angles using two high-resolution DC servomotors. The two PEDs will carry the spindle to coincide with the surface normal, keeping the vertex of the drill bit still to avoid repeated adjustment and position compensation. A series of experiments was conducted on an aeronautical drilling robot platform with a precise NAC. The effect of normal adjustment on bore diameter, drilling force, burr size, drilling heat, and tool wear was analyzed. The results validate that using the NAC in robotic drilling results in greatly improved vertical drilling quality and is attainable in terms of intelligence and accuracy. (C) 2015 The Authors. Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.

关键词： Drilling robot Eccentric disk Normal adaptive Normal adjustment cell Surface normals

Analysis of surface emitting distributed-feedback quantum cascade laser based on a surface-plasmon waveguide

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Journal of Semiconductors 2010年第11期31卷 62-66页

作者：郭万红陆全勇刘俊岐张伟江宇超李路王利军刘峰奇王占国 Key Laboratory of Semiconductor Materials Science Institute of SemiconductorsChinese Academy of Sciences

An analysis of a surface emitting distributed-feedback quantum cascade laser（DFB QCL） based on a surface-plasmon waveguide is *** second-order grating realized by the sole patterning of the top metal provides strong *** analysis is based on a coupled-mode theory derived from exact Floquet-Bloch solutions of the infinite periodic *** surface outcoupling efficiency and threshold gain for the optimized device design are 43%and 12 cm-1,respectively,which represent great improvements on the conventional dielectric waveguide based DFB QCL with typical values of 17.5%and 20 cm-1.

关键词： quantum cascade laser distributed feedback lasers surface plasmon waveguide surface emission

Succinate-bonded pullulan: An efficient and reusable super-sorbent for cadmium-uptake from spiked high-hardness groundwater

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Journal of Environmental Sciences 2015年第11期27卷 51-58页

作者： Azhar Abbas Muhammad Ajaz Hussain Muhammad Amin Muhammad Sher Muhammad Nawaz Tahir Wolfgang Tremel Department of Chemistry University of Sargodha institute of Inorganic and Analytical Chemistry Johannes Guttenberg University

Chemically modified pullulan was evaluated for its sorption efficiency and selectivity to remove cadmium（Cd） from spiked high-hardness groundwater（GW）. Pullulan esterified with succinic anhydride using dimethylaminopyridine showed a fairly high degree of substitution value as confirmed by1 H NMR spectroscopy. Pullulan succinate（Pull-Suc） was converted into the sodium salt（Pull-Suc-Na）. The effect of contact time（5–200 min） and p H（2–8） on Cd-uptake by the sorbent（Pull-Suc-Na） was investigated. The sorbent showed more than 90% Cd-removal in first 15 min from distilled water（DW） and GW solution,respectively. Comparison of Pull-Suc-Na with other polysaccharidal sorbents suggested its high efficiency（DW 476.2 mg/g and GW 454.5 mg/g） and selectivity for the removal of Cd by an ion exchange mechanism, which is further supported by the negative Gibbs free energy values calculated from Langmuir isotherms. A Langmuir isotherm kinetic model provided the best fit for the sorption of Cd using Pull-Suc-Na. The sorbent showed a negligible decrease in Cd-uptake over three regeneration cycles. The thermal stability testing of the sorbents indicated that Pull-Suc-Na（sorbent） is more stable than Pull-Suc.

关键词： Adsorption Cadmium Modified pullulan Succinylation Thermal stability

Effect of Pulse Parameters on Deposition in Concrete Crack using Pulse Current Electro-deposition

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Journal of Wuhan University of Technology(Materials Science) 2018年第4期33卷 908-914页

作者：储洪强 WANG Tingting JIANG Linhua XU Yi SONG Zijian XU Ning ZHAO Sujing College of Mechanics and Materials Hohai University Nanjing Hydraulic Research institute

To evaluate the effect of pulse parameters on the formation of electrodeposits in concrete cracks, five different types of pulse current were set up, and ZnSO_4 and MgSO_4 solutions were used as the electrolytes. The rate of weight gain, rate of surface coating, rate of crack closure and crack filling depth were measured. Scanning electron microscopy was used to assess the morphology of the electrodeposits, and energy dispersive spectroscopy was used to analyze the mineral composition of the electrodeposits in the cracks. The experimental results demonstrate that, among five different pulse parameters, when T_（on）/T_（off）=0.8 ms/0.8 ms, the healing effect of electro-deposition is the best. The pulse mode hardly affects the mineral composition of the electrodeposits but changes the micromorphology. In addition, for both ZnSO_4 and MgSO_4 solutions, when T_（on）/T_（off）=0.8 ms/0.8 ms, the crystal structure of the electrodeposits is the most uniform and the densest.

关键词： pulse electro-deposition repair of concrete cracks pulse parameters healing effect