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| 1 | Near-infrared to visible up-conversion emissions of Er^(3+) doped Al_2O_3 powders derived from the sol-gel method显示文摘The Er3+ doped Al2O3 powders were prepared by the sol-gel method using the aluminium isopropoxide [Al(OC3H7)3]-derived Al2O3 sols with addition of the erbium nitrate [Er(NO3)3.5H2O]. The different phase structure, including three crystalline types of (Al,Er)2O3 phases, γ, θ, α, and two Er-Al-O phases, ErAlO3 and Al10Er6O24, was obtained with the 1 mol% Er3+ doped Al2O3 powders at the different sintering temperatures of 600―1200℃. The green and red up-conversion emissions centered at about 523, 545 and 660 nm, corresponding respectively to the 2H11/2, 4S3/2→4I15/2 and 4F9/2→4I15/2 transitions of Er3+, were detected by a 978 nm semiconductor laser diodes excitation. The phase structure and OH content had evident influence on the up-conversion emissions intensity. The maximum intensities of both the green and red emissions were obtained respectively for the Er3+ doped Al2O3 powders sintered at 1200 ℃, which was composed mainly of α-(Al,Er)2O3, less of ErAlO3 and Al10Er6O24 phases, and with the least OH content. The two-photon absorption up-conversion process was involved in the green and red up-conversion emissions of the Er3+ doped Al2O3 powders. | DONG Bin GAO YaChen XU XueSong SUN Min LI Lei | 2007 | Chinese Science Bulletin2007，52，19： | 1 |
| 2 | In vitro degradation and surface bioactivity of iron-matrix composites containing silicate-based bioceramic显示文摘Iron-matrix composites with calcium silicate(CS)bioceramic as the reinforcing phase were fabricated through powder metallurgy processes.The microstructures,mechanical properties,apatite deposition and biodegradation behavior of the Fe-CS composites,as well as cell attachment and proliferation on their surfaces,were characterized.In the range of CS weight percentages selected in this study,the composites possessed compact structures and showed differently decreased bending strengths as compared with pure iron.Immersion tests in simulated body fluid(SBF)revealed substantially enhanced deposition of CaP on the surfaces of the composites as well as enhanced degradation rates as compared with pure iron.In addition,the composite containing 20%CS showed a superior ability to stimulate hBMSCs proliferation when compared to pure iron.Our results suggest that incorporating calcium silicate particles into iron could be an effective approach to developing iron-based biodegradable bone implants with improved biomedical performance. | Sanguo Wang Yachen Xu Jie Zhou Haiyan Li Jiang Chang Zhiguang Huan | 2017 | Bioactive Materials2017，2，1： | 1 |
| 3 | Dual-band dynamic reconfigurable intelligent surface for signal enhancement in millimeter wave显示文摘Millimeter wave with large bandwidth,high transmission rate,and low delay is considered a reliable alternative to cope with the spectrum shortage.However,the fast attenuation and narrow beam characteristics make it difficult to achieve long-distance or wide-range applications.Here,a 1-bit dual-band reflective reconfigurable intelligent surface(RIS)for signal enhancement in millimeter wave with 16×16 elements is designed,fabricated,and measured.Different from most existent RIS,dynamic programming is realized at two separate frequency bands by integrating the PIN diodes and field-programmable gate array(FPGA).Particularly,the beam deflection,dual-beam,and multi-beam are created based on the coding theory and convolution operation,proving the effectiveness of wavefront manipulation.Moreover,the far-field patterns and signal power with different coding sequences are measured and compared.It is indicated that the received signal power is 6–7 dB stronger than that without coding,which shows good agreement with the desired expectations.The proposed reconfigurable metasurface exhibits great potential in beam forming,making it a promising candidate for progressive wireless communication applications. | YAO HuiMing DU XinRun WANG HengBin GAO Song PANG YaChen ZHENG HaiRong GONG HuiWen LI Yi XU JianChun ZHANG JianHua BI Ke | 2024 | Science China(Technological Sciences)2024，67，4： | 0 |
| 4 | Switchable optical nonlinear properties of W_(18)O_(49) nanowires by Ag nanoparticles supported显示文摘During the past decades,nonlinear optical(NLO)materials have attracted special interest because of their potential applications in photonic devices,such as optical switching,frequency conversion and electro-optic modulators.Among the finding ways to obtain excellent NLO materials with both large NLO response and short response time,the most common approach is to design and prepare new | Yang Liu XueSong Xu Yang Chen ZhenYi Zhang YaChen Gao KuiChao Liu LiDong Gong Bin Dong | 2017 | Science China(Physics,Mechanics & Astronomy)2017，60，11： | 0 |
| 5 | Sensitivity of solar greenhouse envelopes to the thermal disfigurements and optimal selection of the thermal insulation quilt显示文摘The objectives of the present work are focused on exploration of the reasons for temperature difference in different envelopes,the sensitivity of envelopes of solar greenhouse to thermal disfigurements and optimal selection of the thermal insulation quilt.Theoretical analysis and derivation are conducted according to the experimental results of surface temperature,convective heat transfer,and heat flux density in different envelopes which with thermal disfigurements of solar greenhouse using heat transfer theory.The results revealed that the difference of intrinsic thermal conductivity and thickness of the envelopes leads to difference in the thermal flux and thus in the surface temperature of different envelopes.Compared with the front roof and back roof,the wall is more sensitive to thermal disfigurements.According to the influence of thermal disfigurements on solar greenhouse temperature,the allowable thermal disfigurements area fraction of front roof and back roof are given.Based on the analysis of heat transfer theory and test results,the work given the expression of the thickness and thermal conductivity of thermal insulation quilt under different outdoor minimum temperatures for optimal selection of thermal insulation quilt based on comprehensive considering factors of the solar greenhouse structure,crop demand,outdoor minimum temperature,and insulation quilt properties.The results of this work give technical criterion for whether the envelopes with thermal disfigurements needs to be repaired or replaced,and it also provides theoretical and technical support for design the solar greenhouse as well as methodological guidance for the optimal selection of the thermal insulation quilt. | Yachen Sun Yao Zhang Chenmeng Zhu Shaonan Xu Bowen Liu Yanfei Cao Changji Zhou Yaqi Zhou Zhirong Zou Encai Bao | 2021 | International Journal of Agricultural and Biological Engineering2021，14，5： | 0 |
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