Jiayu Guo
China Jiliang University
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Featured researches published by Jiayu Guo.
Inorganic Chemistry | 2015
Wenxiang Chai; Mingwei Hong; Li Song; Guohua Jia; Hongsheng Shi; Jiayu Guo; Kangying Shu; Bing Guo; Yicheng Zhang; Wenwu You; Xueyuan Chen
Three luminescent polymorphs based on a new copper(I) complex Cu(2-QBO)(PPh3)PF6 (1, PPh3 = triphenylphosphine, 2-QBO = 2-(2-quinolyl)benzoxazole) have been synthesized and characterized by FT-IR, UV-vis, elemental analyses, and single-crystal X-ray diffraction analyses. Each polymorph can reversibly convert from one to another through appropriate procedures. Interestingly, such interconversion can be distinguished by their intrinsic crystal morphologies and colors (namely α, dark yellow plate, β, orange block, γ, light yellow needle) as well as photoluminescent (PL) properties. X-ray crystal structure analyses of these three polymorphs show three different supramolecular structures from 1D to 3D, which are expected to be responsible for the formation of three different crystal morphologies such as needle, plate, and block. Combination of the experimental data with DFT calculations on these three polymorphs reveals that the polymorphic interconversion is triggered by the conformation isomerization of the 2-QBO ligand and can be successfully controlled by the polarity of the process solvents (affecting the molecular dipole moment) and thermodynamics (affecting the molecular total energy). It is also found that the different crystal colors of polymorphs and their PL properties are derived from different θ values (dihedral angle between benzoxazolyl and quinolyl group of the 2-QBO ligand) and P-Cu-P angles based on TD-DFT calculations. Moreover, an interesting phase interconversion between γ and β has also been found under different temperature, and this result is consistent with the DFT calculations in which the total energy of β is larger than that of γ. This polymorphism provides a good model to study the relationship between the structure and the physical properties in luminescent copper(I) complexes as well as some profound insights into their PL properties.
Phase Transitions | 2013
Jiayu Guo; Mei Tang; Haifeng Ling; Xiazhen Yang
Vinyltriethoxysilane based inorganic–organic glasses dispersed with 4′-n-pentyl-4-cyanobiphenyl nematic liquid crystal are designed to fabricate a new type of gel glass dispersed with liquid crystal. Scanning electron microscopy shows that the nematic liquid crystal phase, occupying the interconnected cavities, is continuously embedded in the inorganic–organic matrixes. The effect of the nematic liquid crystal weight concentration on the morphology is investigated. The differential scanning calorimetry shows that the nematic-isotropic transition temperature depends on the nematic liquid crystal weight concentration. The Raman spectra show that there are no obvious Raman frequency shifts, compared with pure nematic liquid crystal. The in situ diffuse reflectance FTIR spectra show that the integral intensity of bands of hydroxyls has not varied.
Journal of Nanoscience and Nanotechnology | 2018
Jiali Shen; Haijiao Zhan; Jiayu Guo; Wei Liu; Bing Guo; Hangyan Shen
We have developed a new solution-phase chemical reduction method for the synthesis of poly(vinyl alcohol) coated copper nanoparticles in aqueous solution. Copper nitrate is used as the precursor, sodium hypophosphite as the reducing agent, and poly(vinyl alcohol) as the coating agent. The synthesis of copper nanoparticles could be completed within several hours and the copper nanoparticles in powder form could be stored within one week in ambient condition. In Ar atmosphere, the complete thermal decomposition temperature of coated layer was lower than 450 °C. The antioxidative properties of poly(vinyl alcohol) coated copper nanoparticles were evaluated compared to that of polyvinylpyrrolidone coated copper nanoparticles.
Journal of Materials Engineering and Performance | 2018
Wei Liu; Miao Zheng; Xiaorong Wang; Zhonghua Fan; Dingkun Yu; Rong Chen; Hangyan Shen; Jiayu Guo; Bing Guo; Peng He
Mechanical alloying was used to prepare an Ag-Cu-Sn brazing alloy with the low amounts of intermetallic compounds. X-ray diffraction and differential scanning calorimetry were carried out to investigate the phase transformation of the as-milled samples. It seemed that the intermetallic compounds experienced the stage of synthesis-decomposition-resynthesis in the ball milling process. By controlling the ball milling time and tin contents, the solid solution phases of Ag (Cu, Sn) and Ag (Cu) were achieved in the 60Ag30Cu10Sn sample after milling for 40xa0h. Although the intermetallic compound will be generated during the brazing process, the improvement of their distributed morphology is beneficial for the good bonding interface of the joint with stainless steel substrate.
Microelectronics Reliability | 2017
Yang Wang; Wenxiao Liu; Wei Liu; Peng He; Zhonghua Fan; Xiaorong Wang; Dingkun Yu; Jiayu Guo; Bing Guo; Hangyan Shen
Abstract SnAgCu alloy with low melting point and good soldering property is a good candidate for the Sn/Pb eutectic. In this paper, SnAgCu nanoparticles were synthesized by a chemical reduction method. The particle size and the melting point are controlled by modifying the process parameters, including reaction temperature, surfactant concentration and dropping speed of precursor. The lowest melting onset temperature is observed at 199.1xa0°C, which is 18xa0°C lower than that of commercially available SnAgCu solder alloy. The tensile strength of the as-synthesized reaches 34.3xa0MPa, which reveals a good solderability property.
Journal of Nanomaterials | 2017
Wei Liu; Jiayu Guo; Zhonghua Fan; Xiaorong Wang; Dingkun Yu; Rong Chen; Shisheng Huang; Peng He
We have investigated the influence of heat treatment on the morphologies of copper nanoparticles based films on glass slides by a spin coating method. The experiments show that heat treatment can modify the sizes and morphologies of copper nanoparticles based films on glass slides. We suggest that through changing the parameters of heat treatment process may be helpful to vary the scattering and absorbing intensity of copper nanoparticles when used in energy harvesting/conversion and optical devices.
Materials Letters | 2009
Jiayu Guo; Xiangyu Ye; Wei Liu; Qiong Wu; Hangyan Shen; Kangying Shu
Materials Letters | 2015
Wen-Xiang Chai; Xiaoli Zhang; Li Song; Mingwei Hong; Hongsheng Shi; Congyong Wang; Jiayu Guo; Xijuan Zheng; Gang Chen; Kangying Shu
Solid State Ionics | 2011
Hangyan Shen; Bin Guo; Hideki Maekawa; Jiayu Guo; Kangying Shu
Archive | 2011
Hangyan Shen; Kangying Shu; Hongsheng Shi; Jiayu Guo; Bing Guo; Chunju Lu