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31.
Baofu Qiu Xiaoming Duan Zhuo Zhang Delong Cai Ning Liao Peigang He Dechang Jia Yu Zhou 《Ceramics International》2021,47(1):73-79
The effects of La2O3–Al2O3–SiO2 addition on the thermal conductivity, coefficient of thermal expansion (CTE), Young's modulus and cyclic thermal shock resistance of hot-pressed h-BN composite ceramics were investigated. The samples were heated to 1000 °C and then quenched to room temperature with 1–50 cycles, and the residual flexural strength was used to evaluate cyclic thermal shock resistance. h-BN composite ceramics containing 10 vol% La2O3–Al2O3 and 20 vol% SiO2 addition exhibited the highest flexural strength, thermal conductivity and relatively low CTE, which were beneficial to the excellent thermal shock resistance. In addition, the viscous amorphous phase of ternary La2O3–Al2O3–SiO2 system could accommodate and relax thermal stress contributing to the high thermal shock resistance. Therefore, the residual flexural strength still maintained the value of 234.3 MPa (86.9% of initial strength) after 50 cycles of thermal shock. 相似文献
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采用异佛尔酮二异氰酸酯(IPDI)、聚乙二醇200、400、600、800(PEG200、PEG400、PEG600、PEG800)、2,2-二羟甲基丙酸(DMPA)、1-苯基-1,2-乙二醇、中和剂三乙胺(TEA)、甲乙酮肟等为原料,制备了一种阴离子聚氨酯分散剂.通过FTIR、GPC、TG表征了分散剂的结构与性能.利用自制的分散剂采用研磨法制备了液体靛蓝分散液,以液体靛蓝分散液粒径、离心稳定性、储存稳定性为指标,探讨了分散剂链长、用量对分散液性能的影响.结果表明,研磨1 h后,以PEG400为软段合成的聚氨酯分散剂用量为染料质量的60%时制备的液体靛蓝粒径为277.1 nm,1000 r/min离心稳定性达到93.98%,3000 r/min离心稳定性为51.13%,常温放置7 d后粒径变化在20 nm以内,染色后织物的颜色深度(K/S)为10左右,约是粉状靛蓝染色K/S的2倍,染色织物的颜色性能并未改变,SEM显示分散体颗粒大小分布均匀,与分散剂甲基萘磺酸钠的甲醛缩合物(MF)和木质素85A相比,其分散体系稳定性差别不大. 相似文献
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目的建立一种快速、低成本检测染色梅鱼中日落黄、柠檬黄的方法。方法将染色梅鱼剥皮,鱼皮经70%甲醇氨水提取液提取,经EclipseXDB-C_(18)色谱柱分离,以甲醇和乙酸铵水溶液为流动相,进行梯度洗脱,流速为1.0 mL/min,柱温35℃,利用紫外检测器检测日落黄、柠檬黄的含量。结果日落黄、柠檬黄在1.25、2.5、12.5、25 mg/kg添加水平的加标回收率为80%~90%,相对标准偏差小于10%(n=6),柠檬黄检出限为0.05 mg/kg,日落黄检出限为0.025 mg/kg。结论该方法快速、准确、成本低,适合染色梅鱼中日落黄、柠檬黄的快速检测。 相似文献
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Global decrease in crude oil resources and frequent crude oil leaks cause the energy crisis and ecological pollution. The absorption and release of leaked crude oil through absorption materials are a necessary process for environmental protection and recycling. In this article, a CO2-responsive olefin copolymer was obtained by copolymerization of styrene and an amine-containing olefin monomer. The structure of resultant copolymer was characterized by FTIR; thermal properties and CO2-responsive morphology changes were determined by DSC/TGA and SEM, respectively. Copolymers had certain absorption capacity for toluene with absorption rate up to 180.0%. The absorbed toluene could be released upon CO2 stimulation with desorption rate up to 84.6%. The CO2-responsive copolymer could be regenerated through a simple heating process and showed stable absorption–desorption performance even after being recycled for 4 times. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47439. 相似文献
37.
Yan Xiong Xianwu Du Mingyu Xiang Hao Wang Weimin Wang Zhengyi Fu 《Journal of the European Ceramic Society》2018,38(12):4167-4172
The densification behaviors of pure B4C and B4C-ZrO2 mixtures were compared during hot pressing. The results showed that in-situ formed ZrB2 effectively enhanced the densification process of B4C-ZrO2 mixtures, more significantly during the intermediate stage. Within the relative density ranging from 0.75 to 0.90, the B4C-15?wt%ZrO2 mixture (B15Z) achieved the maximum densification rate as twice much as that of pure B4C. The stress exponent n>3 indicated plastic deformation was the dominant densification mechanism of B15Z. The viscosities of plastic flow were evaluated using Murray-Rodger-William equation and the viscosity of B15Z was only a quarter of that in pure B4C. The sintering activation energy was calculated to be 305.9?kJ/mol for pure B4C and 197?kJ/mol for B15Z, respectively. It was proposed that the lower viscosity of plastic flow and activation energy accelerated the sliding and propagating motions of plastic flow, by which underlain the enhanced densification behaviors of B4C-ZrO2 mixtures. 相似文献
38.
Functional expression and synergistic cooperation of xylan‐degrading enzymes from Hypocrea orientalis and Aspergillus niger
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