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Concise synthesis of NaTi_2(PO_4)_3 nanocrystals with size and morphology control

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Chinese Chemical Letters 2019年第2期30卷 517-520页

作者： Hanqing Dai Wenqian Xu kehan yu Wei Wei School of Electronic and Optical Engineering Nanjing University of Posts and Telecommunications

NaTi_2 (PO_4)_3 (NTP) nanocrystals with high room-temperature ionic conductivity of 1.1×10~3 S/cm were prepared by a concise solvothermal method at 140 ℃ for 3 h, and the aspect ratios of all the NTP nanocrystals are the closest to 0.7. It implies a moderate size-distribution of NTP nanocrystals obtained at 140 ℃ for 3 h is helpful for increasing packing density, and the packing density is the larger, so its conductivity is the higher. The controllability over size and morphology of the NTP nanocrystals via solvothermal temperature and time were investigated. The results suggest that our method is of great potential in synthesizing NTP nanocrystals with high room-temperature ionic conductivity at low cost.

关键词： Nanocrystal Morphology Aspect ratio Size-distribution Ionic conductivity

Synthesis and optical properties of LiNd(PO_3)_4 nanocrystals dispersion in DMSO/TBE

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Journal of Rare Earths 2019年第6期37卷 580-584页

作者： Zhongyue Wang Zhen Yang Ruilin Zheng kehan yu Peng Lv Chunxiao Liu Wei Wei College of Electronic and Optical Engineering & College of Microelectronics (EOM) Nanjing University of Posts and Telecommunications (NUPT)

Lanthanide doped nanocrystals with strong fluorescence, long lifetime at high doping concentrations have great potential application in bio-imaging and liquid gain medium. LiNd(PO_3)_4(LNP) crystal was reported to be one of the most excellent laser crystals with high Nd3+ concentration, and their nanocrystals synthesized via improved combustion method for the first time had strong emission intensity and long fluorescence lifetime of 122 μs. Besides,LiNd(PO_3)_4 nanocrystals can be dispersed in mixed solvents of DMSO/TBE(CHBr2 CHBr2) to form a transparent colloidal dispersion, and Judd-Ofelt theory was used to evaluate their optical parameters. In summary, LiNd(PO_3)_4 nanocrystals possess long lifetime(116 μs), low solvents quenching rate(4.9%), large emission cross section(7.63 × 10^(-20) cm^2) and high quantum yield(35.2%) under high Nd3+ ions concentration(1×10^(20) cm^(-3)), which would be the most competitive colloidal gain medium of optical amplification and laser with LD pump and potential biomaterial with low particles concentration.

关键词： LNP Index-matching matching Fluorescence lifetime High quantum yield Rare earths

High-Energy Na_(4)MnCr(PO_(4))_(3)@C Cathode for Solid-State Sodium Metal Batteries

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Energy Material Advances 2023年第1期4卷 281-293页

作者： Zhongyue Wang Cheng Tang Zhi Wang Qing Zhang Peng Lv kehan yu Jiajin Zheng Wei Wei College of Electronic and Optical Engineering and College of Flexible Electronics(Future Technology) Nanjing University of Posts and TelecommunicationsNanjing 210023PR China

Developing high-energy cathode for sodium ion batteries(SIBs)that enables 3-electron reaction is the most effective way to reduce high cost and solve range anxiety and safety ***,a novel NASICON-type Na_(4)MnCr(PO_(4))_(3)(NMCP)is synthesized as a high-energy cathode for *** as-prepared 6.4 wt%carbon-coated NMCP(NMCP@C)cathode annealed at 700°C delivers a discharge capacity of 107.3 mA h g^(−1)@0.1C,high rate capability up to 15C,and well capacity retention of 69.3%after 500 cycles at 5C within 1.4~4.3 ***,it also provides an exciting reversible capacity of 164.3 mA h g^(−1)@0.1C within 1.4~4.6 V and an ultrahigh energy density of 523.6 Wh kg^(−1).Moreover,high sodium ion diffusion coefficients(DNa+,10^(−12)~10^(−9) cm^(2) s−1)demonstrate the superior electrode process kinetics,and both solid solution and 2-phase reactions are involved in the sodium ion extraction/insertion process through ex situ x-ray diffraction ***_(3.3)La_(0.3)Zr_(1.7)Si_(2)PO_(12) with 3 wt%Na_(2)B_(4)O_(7) additive(NLZSP(NBO3))ceramic electrolyte is utilized to assemble NMCP@C//NLZSP(NBO3)//Na solid-state sodium metal batteries for the first time,which reveals an initial discharge capacity of 99.1 mA h g^(−1)(1.4~4.3 V)and 121.7 mA h g^(−1)(1.4~4.6 V)at 0.1C and an excellent cycling performance(capacity retention of 75.8%/72.6%after 100 cycles at 0.2C)at 30°*** these confirm that NMCP@C is a high-energy cathode with great practical potential for all-solid-state SIBs.

关键词： Solid cycling ceramic

PbS quantum dots as a saturable absorber for ultrafast laser

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Photonics Research 2018年第11期6卷 1028-1032页

作者： LING yuN YANG QIU CONGHAO YANG JIE XING kehan yu XIANGXING XU WEI WEI College of Electronic and Optical Engineering & College of Microelectronics Nanjing University of Posts and Telecommunications Jiangsu Key Laboratory of Biofunctional Materials School of Chemistry and Materials Science Nanjing Normal University

Low-dimensional nanomaterials, owing to their unique and versatile properties, are very attractive for enormous electronic and optoelectronic applications. PbS quantum dots(QDs), characterized by a large Bohr radius and size-tunable bandgap, are especially interesting for photonic applications in the near-infrared region. Here, oleic acid capped colloidal PbS QDs as a saturable absorber are investigated for ultrashort-pulse generation. The PbS QDs exhibit outstanding nonlinear saturable absorption properties at 1550 nm: a modulation depth up to 44.5%and a thermal damage threshold larger than 30 mJ∕cm^2. By incorporating PbS QDs into a fiber laser, a transform-limited soliton pulse as short as 559 fs with a bandwidth of 4.78 nm is realized at 1563 nm. Numerous applications may benefit from the nonlinear saturable absorption properties of PbS QDs, such as near-infrared pulsed lasers and

关键词： QDs PbS ultrafast laser

MICROCRYSTALLINE RARE EARTH COMPLEX DOPED PMMA BULK FOR ORGANIC SOLID-STATE LASERS

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MICROCRYSTALLINE RARE EARTH COMPLEX DOPED PMMA BULK FOR ORGA...

Asia Conference on Nanoscience and Nanotechnology Abstracts Book

作者： XIAOMING QIU LEI ZHAO RONGBIAO yu kehan yu XIANGXING XU LEI JIANG SAMMING SI DAN CHEN LI XU BO PENG WEI HUANGInstitute of Advanced Materials Fudan University Shanghai 200433 China

＜正＞ It is well known that the rare earth elements are good gain media for lasers in inorganic materials such as crystals and glasses. They have been studied extensively and have already been applied to many fields. In recent years, with the rapid development of organic electronics and photonics, organic lasers have been attached more and more importance. Amplified Spontaneous Emission was observed in many organic molecules and laser output was obtained in some of them . At the same time, rare earth complex doped polymer solutions and thin films were also studied . However, up to now, the rare earth doped organic solid-state lasers have not been achieved. In this paper, we focused on preparing the microcrystalline rare earth complex doped PMMA bulk. The rare earth complex Eu（TTA）3（PyON） was dissolved into the MMA monomer, through the latex polymerization, the rare earth complex was well dispersed into the PMMA organic matrix in the form of microcrystal ranging from 60nm to 80nm. The latex was poured into a mold and heated and finally a transparent organic bulk was obtained. By further studying its optical properties and other physical properties, we are trying to get laser output for developing rare earth doped organic solid-state lasers and amplifiers.

关键词： microcrystalline bulk otganic laser

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基于石墨烯涂覆倾斜光纤光栅的折射率传感

中国激光 2017年第12期44卷 263-268页

作者：黄梦顾昌晟孙兵杨从浩余柯涵张祖兴南京邮电大学光电工程学院江苏南京210023

采用等离子体增强化学气相沉积法,通过设置等离子体发生器的功率和生长时间来控制石墨烯的层数,生长出了高质量和高透明度的石墨烯;将3.7nm厚度的石墨烯(约11层)涂覆在倾斜角度为8°的光纤光栅上进行实验,测得光栅在折射率1.33附近的灵... 详细信息

采用等离子体增强化学气相沉积法,通过设置等离子体发生器的功率和生长时间来控制石墨烯的层数,生长出了高质量和高透明度的石墨烯;将3.7nm厚度的石墨烯(约11层)涂覆在倾斜角度为8°的光纤光栅上进行实验,测得光栅在折射率1.33附近的灵敏度达到-1.57161RIU^(-1),与未镀石墨烯的光栅相比,灵敏度约提高20倍。在光纤光栅表面涂覆石墨烯可明显提高倾斜光栅在低折射率区域的灵敏度,在生物、化学、食品安全和水环境监测等领域具有潜在应用价值。

关键词：传感器折射率传感倾斜光纤光栅等离子体增强化学气相沉积法石墨烯

A NOVEL INORGANIC MATERIAL FOR LIQUID LASER

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A NOVEL INORGANIC MATERIAL FOR LIQUID LASER

Linear-Quadratic Pareto Cooperative Game for Mean-Field Backward Stochastic System

Asia Conference on Nanoscience and Nanotechnology Abstracts Book

作者： Zhongcheng FAN Rongbiao yu Xiaoming QIU kehan yu Xiangxing XU Lei JIANG Sanming SI Dan CHEN Li XU Lei ZHAO Bo PENG Wei HUANGInstitute of Advanced Materials Fudan University Shanghai 200433 China.

＜正＞ Solid state lasers have been widely used in defense works, mechanical processing, information technology and many other areas. However, they still have quite a few disadvantages. As is well known, it is costly and difficult to homogeneously manufacture the crystal and glass bulks in big size. These solid bulks can not avoid defects, which will develop damaged spots when running before the spots grow rapidly. The growing spots are very harmful and even dangerous for the performance and maintenance of high power laser systems. What is more, it is awfully difficult to cool the solid lasing materials, thus the running cycle period and working life shrank badly, and the laser system become low repeated usable. Fortunately, inorganic liquid laser can gracefully tackle such nuts. First of all, it is pretty easy to get lasing liquid in almost unlimited volume at a uniform density. As far as most thin liquids are concerned, the structure is nearly ideally homogenized when flowing. Even if some defects are developed while lasing, the spots will get resolved by the flowing ambient branches to prevent such damage. It is also quite convenient to realize the high repeated laser to prolong both the running cycle period and working life. In our work, neodymium doped yttrium aluminum garnet （Nd: YAG） was manufactured through the aqueous solutions of aluminum, yttrium and neodymium chlorides. After calcination and sinter, Nd: YAG nanocrystals by the size of tens of nanometers were realized. They were homogeneously dispersed in inorganic solvent, such as POCl3, BBr3 and TiCl4, with properly adjusted refractive index and density. Tbe laser emission was also achieved while the mixture was recirculated. It might have a potential application in high repeated laser system.

关键词： liquid laser inorganic nanosized particle.

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Journal of Systems Science & Complexity 2024年第3期37卷 947-964页

作者： WANG yu School of Control Science and Engineering Shandong UniversityJinan 250061China

This paper focuses on a Pareto cooperative differential game with a linear mean-field backward stochastic system and a quadratic form cost functional. Based on a weighted sum optimality method, the Pareto game is equivalently converted to an optimal control problem. In the first place,the feedback form of Pareto optimal strategy is derived by virtue of decoupling technology, which is represented by four Riccati equations, a mean-field forward stochastic differential equation(MF-FSDE),and a mean-field backward stochastic differential equation(MF-BSDE). In addition, the corresponding Pareto optimal solution is further obtained. Finally, the author solves a problem in mathematical finance to illustrate the application of the theoretical results.

关键词： Backward stochastic differential equation linear-quadratic control mean-field Pareto optimality

Approximate analytical solutions for threedimensional ascent trajectory of a solid-fuel launch vehicle with time-varying mass flow rate

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Chinese Journal of Aeronautics 2024年第10期37卷 275-293页

作者： Qi yu Wanchun CHEN Wenbin yu School of Astronautics Beihang UniversityBeijing 102206China

In the scenario that a solid-fuel launch vehicle maneuvers in outer space at high angles of attack and sideslip for energy management,Approximate Analytical Solutions(AAS)for the threedimensional(3D)ascent flight states are derived,which are the only solutions capable of considering time-varying Mass Flow Rate(MFR)at *** uneven MFR makes the thrust vary nonlinearly and thus increases the difficulty of the problem *** AAS are derived based on a 3D Generalized Ascent Dynamics Model(GADM)with a normalized mass as the independent *** simplify some highly nonlinear terms in the GADM,several approximate functions are introduced carefully,while the errors of the approximations relative to the original terms are regarded as minor ***,a finite series with positive and negative exponents,called Exponent-Symmetry Series(ESS),is proposed for function approximation to decrease the highest exponent in the AAS so as to reduce computer round-off *** calculate the ESS coefficients,a method of seeking the Optimal Interpolation Points(OIP)is proposed using the leastsquares-approximation *** to the artful design of the approximations,the GADM can be decomposed into two analytically solvable subsystems by a perturbation method,and thus the AAS are obtained ***,to help implement the AAS,two indirect methods for measuring the remaining mass and predicting the burnout time in flight are put forward using information from *** results verify the superiority of the AAS under the condition of time-varying MFR.

关键词： Approximate analytical solutions 3D ascent trajectory Solid-fuel launch vehicle Uneven thrust Energy management