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991.
Shiwei Deng Lexing Liang Zhe Tang Haifeng Yuan Cong Zhang Zijie Li Junjing Duan Jianqi Qi Tiecheng Lu 《Journal of the American Ceramic Society》2023,106(4):2252-2260
Calcium oxide (CaO) as sintering additive was first used to fabricate La0.4Gd1.6Zr2O7 transparent ceramics by a simple solid-state reaction and one-step vacuum sintering method. The effects of CaO dopant amount on the densification, as well as sintering behaviors and microstructure evolution of the as-fabricated La0.4Gd1.6Zr2O7 ceramics, were systematically investigated. Under the different sintering temperatures, the relationships during the sintering process between grain growth and zpore elimination were analyzed as well. It was found that 0.1 wt% CaO doping can effectively control the rate of grain growth and promote densification dominated by surface diffusion. Furthermore, Ca2+ entered the lattice of La0.4Gd1.6Zr2O7 ceramics to accelerate ion diffusion and suppress grain boundary migration. With the introduction of 0.1 wt% CaO doping, the highly transparent La0.4Gd1.6Zr2O7 ceramics (T = 80.4% at 1100 nm) were successfully fabricated at the traditional sintering temperature (1850°C). 相似文献
992.
Tianhao Li Wei Zhang Liantai Duan Ke Chen Qing Huang Yinsheng Li Zhengren Huang Liu He Yujie Song 《Journal of the American Ceramic Society》2023,106(6):3329-3335
Trimethylsilyl-substituted polysilazanes were designed and successfully synthesized. They were used to fabricate high-purity stoichiometric Si3N4 ceramics through pyrolysis process. Trimethylsilyl groups improved the stability of polysilazanes and easily escaped during pyrolysis, which effectively reduced oxygen and carbon content in the final polymer-derived Si3N4. The C content of Si3N4 ceramic was below 0.06 wt%, and the O content was below 1.2 wt%. The Si3N4 ceramics remained amorphous up to 1400°C, yet they were completely transformed into α-Si3N4 at 1500°C. Synergistic effect from low oxygen and carbon content contributed to highly stable amorphous state of Si3N4 till high temperatures. This amorphous Si3N4 ceramics could be used in cutting-edge technology where high purity is compulsory. 相似文献
993.
Yi Zhong Yun Wang Zhenliang Yang Bingqing Li Jingkun Xu Zhiyi Wang Liang Xie Limei Duan Fengyun Hu Mingfu Chu Rui Gao Pengcheng Zhang Bin Bai 《Journal of the American Ceramic Society》2023,106(10):5723-5734
In this work, the sintering kinetics of pure UO2 and 0.5 wt.%MnO-doped UO2 was studied by a high-temperature dilatometer heated up to 1500°C. In addition, the sintering behavior of pure UO2 and 0.5 wt.%MnO-doped UO2 was studied by pressureless sintering technique. The results showed that MnO doping enhanced the grain boundary diffusion of UO2, which can effectively decrease the densification temperature and promote grain growth. The sintering temperature of UO2 was significantly reduced by about 200°C with the addition of 0.5 wt.%MnO. The microscopic morphology studies showed that there were still fine particles agglomerated, forming sintered spheres in the matrix even if no severe agglomeration and bimodal size distribution were observed in raw UO2 powder. The microstructure evolution of the sintered sphere and UO2 matrix during the densification process was studied by isothermal sintering. Finally, the present analyses indicated that the densification of UO2 matrix can be accelerated by adding MnO or increasing the sintering temperature, thus improving the densification inhomogeneity of UO2 matrix. 相似文献
994.
Yingjie Guo Zan Chen Xue Hu Yawei Du Cuijia Duan Claudia Li Sibudjing Kawi Yinhui Li 《应用聚合物科学杂志》2024,141(3):e54818
Imino hypercrosslinked polymers (NH-HCPs), amino hypercrosslinked polymers (NH2-HCPs), and carboxyl hypercrosslinked polymers (COOH-HCPs) were synthesized through cross-linking and Friedel-Crafts reactions to serve as highly efficient adsorbents for doxycycline hydrochloride (DOX) in water. These polymers, NH-HCPs, NH2-HCPs, and COOH-HCPs, exhibited specific surface areas measuring 450, 267.576, and 94.39 m2/g, respectively. The adsorption kinetics of DOX onto these polymers were consistent with the pseudo-second-order model, while the adsorption isotherms followed the Langmuir model (NH-HCPs) and Freundlich model (NH2-HCPs and COOH-HCPs), respectively. The maximum DOX adsorption capacities for NH-HCPs, NH2-HCPs, and COOH-HCPs were 166.82, 132.43, and 72.07 mg/g, respectively. Simulation results indicated that COOH-HCPs exhibited the strongest adsorption capability due to a substantial presence of oxygen and nitrogen groups on its surface, enabling the formation of hydrogen bonds with DOX. However, its actual adsorption capacity was the lowest among the polymers, indicating that structural adjustments played a more significant role in improving adsorption performance compared to functional adjustments. Adsorption experiments conducted with NH-HCPs and NH2-HCPs further supported this hypothesis. The primary DOX adsorption mechanism of NH-HCPs, NH2-HCPs, and COOH-HCPs involved the H-bonding of oxygen and nitrogen functional groups, along with other mechanisms such as π-π conjugated effects, pore-filling effects, electrostatic interactions, and acid–base interactions. Overall, this study demonstrates the effectiveness of NH-HCPs, NH2-HCPs, and COOH-HCPs in DOX removal from water, highlighting the significant influence of structural adjustments on adsorption performance. 相似文献
995.
板栗壳棕色素的提取及理化性质研究 总被引:9,自引:0,他引:9
研究了板栗壳棕色素的提取及其理化性质。实验结果表明,该色素对光、热稳定性很好,具有一定应用开发价值。 相似文献
996.
997.
998.
鸡腿菇营养香肠的研制开发 总被引:6,自引:1,他引:6
研究了在肠馅中添加一定量的鸡腿菇对营养香肠感官评价和质构特性的影响,通过单因素和正交试验表明,蔬菜营养肠的最佳配方为:猪肉100%,鸡腿菇15%,玉米淀粉10%,复合磷酸盐0.4%,食盐6%,香辛料1%、味素0.3%、水适量。该产品具有独特的风味和良好的营养保健作用,市场前景广阔。 相似文献
999.
1000.
在我国自主实施的交会对接任务中,2个空间目标进行了数次对接试验,在近距离导引段使用星间测量数据进行自主导引。针对2个航天器对接过程中的星间测量数据建立观测模型,并设计了多目标定轨的算法,将单目标的绝对测量融合到两目标联合定轨的技术中,实现了对空间多个目标的精确定轨。最终分析表明,星间测量数据优于地面测量精度,多目标定轨达到了地面精确测控的水平,同时避免了由于多目标同时跟踪而导致的地面测控资源分配的问题,为后续载人航天任务的测控模式提供了借鉴。 相似文献