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991.
992.
Shishan Xue Guanfei Liu Jingjuan Lai Peng An Yang Liu Yuanpeng Wu Yu Wang Zhiyong Ye Qiao Tang Hongwei Zhou 《大分子材料与工程》2021,306(11):2100415
Self-healing hydrogels often possess poor mechanical properties which largely limits their applications in many fields. In this work, boron nitride nanosheets are introduced into a network of the poly(vinyl alcohol)/borax (PVA/borax) hydrogels to enhance the mechanical properties of the hydrogel without compromising the self-healing abilities. The obtained hydrogels exhibit excellent mechanical properties with a tensile strength of 0.410 ± 0.007 MPa, an elongation at break of 1712%, a Young's Modulus of 0.860 ± 0.023 MPa, and a toughness of 3.860 ± 0.075 MJ m−3. In addition, the self-healing efficiency of the hydrogels is higher than 90% within 10 min at room temperature. Benefiting from the excellent self-healing properties, the shapeability of the hydrogel fragments is observed using different molds. In addition, the hydrogels display rapid pH-driven shape memory effects and can recover to their original shape within 260 s. Overall, this work provides a new approach to hydrogels with integrated excellent mechanical properties, self-healing abilities, and rapid pH-driven shape memory effects. 相似文献
993.
Zhiyong Fang Xiaohui Lai Jian Zhang Rui Zhang 《International Journal of Applied Ceramic Technology》2021,18(4):1106-1113
K2TiF6:Mn4+ is an attractive narrow-band red-emitting phosphor for warm white light-emitting diodes (LEDs). Nevertheless, the hexafluoride phosphor is liable to deliquesce in moist environments, which leads to a sharp deterioration performance of luminescence. Surface modification of K2TiF6:Mn4+ phosphor with SrF2 coating has been introduced, with the aid of KHF2 transition layer to moderate the lattice mismatch. The reaction mechanism is discussed in detail, as so as the influence of SrF2 coating on the luminescence intensity. The SrF2 coating is able to prevent the hydrolysis of internal [MnF6]2− group; thereby, the luminescence intensity retains over 90% of initial value after being immersed in distilled water for 2 h. The LED devices fabricated with commercial Y3Al5O12:Ce3+ and as-modified K2TiF6:Mn4+ phosphors exhibit bright white light with tunable chromaticity coordinate, correlated color temperature, and color rendering index. It enlightens a convenient method to enhance the moisture resistance of Mn4+ doped fluoride phosphors for commercial application in the field of white LEDs. 相似文献
994.
Yang Zhu Xiangli Meng Qiang Zhang Liansheng Yan Hong Cui 《International Journal of Applied Ceramic Technology》2021,18(4):1330-1341
A 3D architecture carbon fiber preform, specifically fine-woven cloth and punctured felt preform, is used to manufacture a novel advanced Cf/C-SiC-ZrC composite. The composite matrix is produced by chemical vapor infiltration (CVI) plus precursor infiltration and pyrolysis (PIP) process and finalized by using a chemical vapor deposition (CVD) of SiC coating to make the final density of the material reach 1.95 g/cm3. The organic precursors of SiC and ZrC have a weight ratio of 4:1 in a xylene solute. The composite mechanical properties, such as tensile, compression, bending, shear, and Z-direction load bearing, are introduced under analysis to find possible applications for the composite. What is more, scanning electron microscope (SEM) images are employed to illustrate the failure behavior of the ceramic composite. The results showed that the punctured filament tows will be beneficial, not only for the composite to withstand compression force up to 308.6 MPa and shear strength to 18.14 MPa but also for the alternatively stacked weave piles and short fiber layers to support the punctured bundles, as well as to hold the composite structure under mechanical forces from different orientations, which is believed to reinforce the ceramic matrix for some high pressure and severe ablation applications. 相似文献
995.
Eric W. Neuman Benjamin J. Lai Jeremy L. Watts Gregory E. Hilmas William G. Fahrenholtz Laura Silvestroni 《International Journal of Applied Ceramic Technology》2021,18(6):2224-2236
Densification behavior, microstructure, and mechanical properties of zirconium diboride (ZrB2) ceramics modified with a complex Zr/Si/O-based additive were studied. ZrB2 ceramics with 5–20 vol.% additions of Zr/Si/O-based additive were densified to >95% relative density at temperatures as low as 1400°C by hot-pressing. Improved densification behavior of ZrB2 was observed with increasing additive content. The most effective additive amount for densification was 20 vol.%, hot-pressed at 1400°C (∼98% relative density). Microstructural analysis revealed up to 7 vol.% of residual second phases in the final ceramics. Improved densification behavior was attributed to ductility of the silicide phase, liquid phase formation at the hot-pressing temperatures, silicon wetting of ZrB2 particles, and reactions of surface oxides. Room temperature strength ranged from 390 to 750 MPa and elastic modulus ranged from 440 to 490 GPa. Vickers hardness ranged from 15 to 16 GPa, and indentation fracture toughness was between 4.0 and 4.3 MPa·m1/2. The most effective additive amount was 7.5 vol.%, which resulted in high relative density after hot-pressing at 1600°C and the best combination of mechanical properties. 相似文献
996.
Hua Feng-Zhen Feng Chao Xie Wei-Nan Luo Yi-Ni Zhang Ling-Mei Zhao Hong 《Journal of Inorganic and Organometallic Polymers and Materials》2021,31(9):3657-3664
Journal of Inorganic and Organometallic Polymers and Materials - Two new coordination polymers, namely, [Cu2(L)2(4,4′-bpy)]n (1) and [Cd(HL)Cl(1,10′-phen)]n (2)... 相似文献
997.
为解决自动壳封焊机机械凸轮式仿形的缺点,提出了基于电子凸轮的控制方案,为实现电子凸轮控制方案,在焊接轨迹形成分析的基础上,建立了焊枪位置控制的数学模型,改进后的自动焊机焊接试验表明,焊接位置误差较小,可以满足生产的需要。 相似文献
998.
999.
用动电位伏安法,动电位光电流测量,表面膜的阴极还原和XRD分析等手段研究了铜在含或不含人血清白蛋白的模拟宫腔液(pH=7)中的电化学和光电化学行为,在不含白蛋白的模拟宫腔液中,铜电极表面生成的Cu2O呈n型光响应;一定量白蛋白存在时使Cu2O的光响应从n型转为p型,Cu2O在模拟宫腔液中呈n型光响应可归因于氯离子对Cu2O的掺杂,白蛋白排斥氯离子对Cu2O的掺杂,使其光响应从n型转为p型。 相似文献
1000.