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991.
992.
993.
氟元素主要存在于磷矿和萤石等矿物中,这些矿物中都伴生有方解石脉石矿物,在浮选分离的弱酸条件下,矿物表面的F-会部分溶出并吸附到矿物表面,从而影响矿物表面性质。本文研究了F-在方解石表面的吸附及其对方解石表面性质的影响机理。结果表明,在矿浆pH 值为5.5时,F-以化学吸附的方式吸附在方解石表面,随着吸附时间的增加吸附量逐渐增加,90 min时方解石对F-的吸附达到平衡。在油酸钠(NaOL)为捕收剂时,F-的存在会降低方解石表面的疏水性。通过Zeta电位测试、溶液化学计算和X射线光电子能谱仪(XPS)分析表明,F-会和方解石表面的Ca2+反应生成CaF2沉淀,占据方解石表面的Ca位点,降低NaOL在方解石表面的吸附量。 相似文献
994.
研究了自蔓延燃烧合成Si3N4粉的氧化处理(在空气气氛中分别于400、600、800℃保温3 h)以及添加的分散剂种类(分别为聚丙烯酸钠、六偏磷酸钠、三聚磷酸钠、木质素磺酸钙)对制备的Si3N4浆料的抗沉降性、ζ电位和黏度的影响。结果表明:1)在空气气氛中于800℃保温3 h氧化处理后,粉体中Si2N2O含量增多;用其制备的浆料的稳定性最好,ζ电位绝对值较大,黏度最小。2)以六偏磷酸钠作为分散剂制备的Si3N4浆料的稳定性较好,ζ电位绝对值最大,黏度最小。3)添加0.021%(w)六偏磷酸钠制备的Si3N4浆料的ζ电位绝对值最大,黏度较小。 相似文献
995.
以乙烯⁃甲基丙烯酸缩水甘油酯共聚物(CE)为扩链剂与聚(3?羟基丁酸酯?co?3?羟基戊酸酯)(PHBV)进行熔融共混,制备了扩链PHBV样品,然后采用超临界CO2(scCO2)釜压发泡法将其在160 ℃、20 MPa下进行物理发泡,成功制备了不同PHBV泡沫。结果表明,与常压差示扫描量热法相比,采用高压差示扫描量热法测量的各组PHBV的结晶温度和熔融温度略微下降;CE的加入提高了PHBV样品的复数黏度(G')和储能模量(η* );随着CE含量的增加,PHBV发泡样品的泡孔密度和发泡倍率逐渐增加,泡孔尺寸逐渐减小。 相似文献
996.
当灰斗内收集的物料粉尘在灰斗下部某部位冷却而板结,出现物料空腔,不能及时有效地被卸灰阀卸走时会形成拱灰现象。仓壁振打器通过机械振动的方式引起灰斗振动,消除物料拱灰现象,但灰斗壳体的剧烈振动会对焊接处造成焊缝开裂。本文所介绍的除尘器灰斗振打电机不仅能够有效消除料层空腔及较大结块对卸灰造成的影响,还可避免对除尘器设备的损坏。 相似文献
997.
为提高聚氨酯泡沫(PUF)的疏水性能,首先采用十六烷基三甲氧基硅烷(HDTMS)对花生壳粉末(PSP)进行改性,得到疏水改性花生壳粉末(H-PSP)。水接触角测试结果表明,改性后H-PSP的水接触角由PSP的0°提高至145.2°。然后采用预聚体法制备了PUF负载H-PSP复合材料(H-PSP-PUF-n,n为H-PSP占聚氨酯预聚体PPU的质量分数)。对H-PSP-PUF-n的结构和性能进行了表征与测试。结果表明,H-PSP的负载提高了泡沫材料的表面粗糙度和力学性能,H-PSP的最佳负载量为PPU质量的10%(H-PSP-PUF-10)。与PUF相比,H-PSP-PUF-10的静态水接触角达到142.4°,较PUF提高了50.4°。对二氯甲烷、石油醚、煤油、二甲苯、环己烷五种油品进行油水分离实验,结果表明,H-PSP-PUF-10对不同油品的吸油倍率在7~9 g/g,而且具有良好的油水选择性。经15次吸附-脱附循环后,H-PSP-PUF-10对各油品的吸油倍率在6.5~8.0 g/g,具有良好的循环利用性。 相似文献
999.
Yanan Wei Yunlei Zhang Bing Li Wen Guan Changhao Yan Xin Li Yongsheng Yan 《中国化学工程学报》2022,44(4):169-181
5-Hydroxymethylfurfural (5-HMF), as a key platform compound for the conversion of biomass to various biomass-derived chemicals and biofuels, has been attracted extensive attention. In this research, using Pickering high internal phase emulsions (Pickering HIPEs) as template and functional metal-organic frameworks (MOFs, UiO-66-SO3H and UiO-66-NH2)/Tween 85 as co-stabilizers to synthesis the dual acid-base bifunctional macroporous polymer catalyst by one-pot process, which has excellent catalytic activity in the cascade reaction of converting cellulose to 5-HMF. The effects of the emulsion parameters including the amount of surfactant (ranging from 0.5% to 2.0% (mass)), the internal phase volume fraction (ranging from 75% to 90%) and the acid/base Pickering particles mass ratio (ranging from 0:6 to 6:0) on the morphology and catalytic performance of solid catalyst were systematically researched. The results of catalytic experiments suggested that the connected large pore size of catalyst can effectively improve the cellulose conversion, and the synergistic effect of acid and base active sites can effectively improve the 5-HMF yield. The highest 5-HMF yield, about 40.5%, can be obtained by using polymer/MOFs composite as catalyst (Poly-P12, the pore size of (53.3 ±11.3) μm, the acid density of 1.99 mmol·g-1 and the base density of 1.13 mol·g-1) under the optimal reaction conditions (130 ℃, 3 h). Herein, the polymer/MOFs composite with open-cell structure was prepared by the Pickering HIPEs templating method, which provided a favorable experimental basis and theoretical reference for achieving efficient production of high added-value product from abundant biomass. 相似文献
1000.
Inhibition of protein misfolding and aggregation is a great challenge in the field of biochemical and biopharmaceutical engineering. Alzheimer's disease (AD) is a protein-misfolding disease, and the interactions between 40-amino-acid-residue β-amyloid peptide (Aβ40) and its N-terminal truncated peptide Aβ11-40 demonstrate that Aβ11-40 may play an important role in the pathological process of AD. However, the effect of inhibitors on Aβ11-40 aggregation and on the cross-amyloid aggregation (co-assembly) between Aβ40 and Aβ11-40 has never been studied. Herein, coaggregation and seeding interactions between Aβ40 and Aβ11-40 as well as the effect of epigallocatechin gallate (EGCG), a small molecule inhibitor, on the cross-amyloid aggregation have been investigated by extensive analyses. It is found that Aβ11-40 participates in the aggregation of Aβ40 and leads to the formation of coaggregates that contain less β-sheet structures than pure Aβ40 aggregates. The aggregation kinetics along with morphologies and secondary structures of the coaggregates are also significantly affected by the Aβ40/Aβ11-40 ratio. EGCG accelerates the nucleation of Aβ40 but retards that of Aβ11-40 by affecting their elongation and secondary nucleation processes in solution and on solid surfaces. Meanwhile, EGCG makes the conformations of the seeding-induced Aβ aggregates more compact, especially for the homologous seedings. Isothermal titration calorimetry measurement indicates that hydrophobic interactions mainly contribute to the inhibition of the two Aβ isoforms by EGCG. The findings of this research have provided new insights into Aβ aggregation and the effect of an important inhibitor and the results would benefit in the development of potent inhibitors against co-assembly of different amyloid proteins. 相似文献