PANG Jian-ming
,
GUO Pei-min
,
ZHAO Pei
钢铁研究学报(英文版)
The reduction-degree of the sample increases and the utilization ratio of gas decreases when the reaction lasts longer time, which indicates that the reaction is faster at the beginning of reduction, while it becomes slower in subsequent process. The higher the reaction temperature, the higher the utilization ratio of gas and the reduction-degree are, but the difference of utilization ratio among the different temperatures becomes smaller with time. The utilization ratio of gas can reach about 8% and the reduction-degree is 80% for 20 min reduction at 850 ℃, indicating that the reduction reaction by CO is very fast at high temperature. The higher the reaction temperature, the higher the apparent reaction rate constant is, but the difference of apparent reaction rate constant among the different temperatures becomes bigger. The apparent activation energy is about 5911 kJ/mol in the fluidized bed experiment. The increase of reduction-degree with gas velocity shows quite good linearity, indicating that at high temperature even higher velocity of reducing gas can be used to improve the productivity of reactor when CO is used as reducing gas. With the increase of charge height, the metallization ratio and the reduction-degree decrease, but the utilization ratio of gas increases.
关键词:
CO
,
fluidized bed
,
fine powder
,
iron ore
,
reduction-degree
GUO Pei-min
钢铁研究学报(英文版)
The activity model of CaO-FeO-SiO2-WO3 quarternary system was established according to the coexistence theory of slag structure and the reduction thermodynamics of scheelite was discussed by applying this model. The activities of SiO2 and WO3 decrease, while that of CaO increases with increasing the basicity of slag. Among SiC, [C] and [Si] reactants, the reducing capability of SiC is the strongest, while that of [C] is the poorest at a high temperature (about 1873 K). It is advantageous to increase the yield of tungsten by increasing the content of [Si] or [C]. Oxidizability of slag has a significant effect on the yield of tungsten. Controlling of basicity and oxidizability of slag can prevent the oxidation loss of tungsten.
关键词:
activity model;scheelite;thermodynamics;direct reduction
GUO Pei-min
钢铁研究学报(英文版)
The deoxidation kinetics of hematite ore with various particle sizes with hydrogen at low temperature and reduction mechanisms were studied using the thermogravimetric analysis. Under the same temperature, after particle size of powder becomes thinner from 107.5μm to 2μm, the surface area of powder and the contact area between powder and gas increase, which makes the deoxidation process of hematite accelerate about 8 times, and the apparent activation energy of deoxidation reaction drops to 36.9 kJ/mol from 78.3 kJ/mol because of activity of ore powder improved with refining gradually. Under the same reaction rate, the reaction temperature of 6.5μm powder decreases about 80℃ than that of 107.5μm powder. Thinner diffusion layer also helps accelerate the reaction with powder refining. The higher the temperature, the greater peak of deoxidation rate is; under the same temperature, the greater the particle size, the smaller the peak of deoxidation rate is; both inner diffuse and interface chemical reaction play an important role in the whole reaction process.
关键词:
iron oxide;low temperature;deoxidation kinetics;thermogravimetric analysis (TGA);reduction mechanism
廖晨棵
,
赵文轸
,
张春婉
,
李磊
复合材料学报
doi:10.3321/j.issn:1000-3851.2008.03.006
用不同溶剂通过两步法制备MoS2填充芳香和半脂肪聚醚酰亚胺(PEI)复合膜,采用乙酸酐和三氟乙酸酐(TFAA)封端.利用IR Prestige-21红外光谱仪表征纯PEI亚胺化程度;采用SDT Q600测试纯PEI的热转变与热稳定性能;用M-200型环块摩擦试验机考察干摩条件下分子柔顺性、封端剂、填料比例对PEI润滑膜摩擦因数一时间(μ-t)曲线的影响,以及载荷、填料比例对稳定服役阶段μ平均值(μ)的影响;采用扫描电镜观察磨损表面形貌,分析磨损机制.结果表明,半脂肪族PEI分子设计在不明显降低热稳定性能的前提下,显著降低了聚合物的Tg.PEI润滑膜的μ值随着摩擦时间的增加先上升后下降,但波动时间较短,μ随后逐渐升高直至润滑失效.柔性结构、三氟乙酸酐封端和适当的填料比有利于改善摩擦性能,填充70 wt%MoS2的氟化酸酐封端PEI-2具有最低为0.027的(μ)值.PEI润滑膜的(μ)值还与载荷、MoS2填料比有关.
关键词:
聚醚酰亚胺
,
脂肪族PI
,
摩擦磨损
,
润滑膜
,
MoS2
侯影飞
,
王金凤
,
刘敏
膜科学与技术
doi:10.16159/j.cnki.issn1007-8924.2016.06.009
用聚砜超滤膜为底膜,以聚乙烯亚胺(PEI)为阳离子添加剂,与聚乙烯醇(PVA)共混制备带正电复合纳滤膜.讨论了制膜条件对膜性能的影响,并用红外光谱、扫描电镜、接触角对膜的化学组成、表面形态和疏水性进行表征.结果表明,随着PEI含量的增加,纳滤膜对二价盐溶液的截留率先增加后减小,最佳制膜条件为:PVA和PEI的质量分数均为2％,PVA与PEI质量比为PVA∶PEI=8∶1,戊二醛的质量分数为2％,硫酸的质量分数为1％;热处理温度为70℃.此时复合纳滤膜对2 g/L MgSO4溶液的截留率为94.52％,通量为5.91 L/(m2·h).复合纳滤膜对4种盐截留率大小顺序为:MgSO4＞MgCl2＞Na2 SO4＞NaCl.添加PEI后的膜表面电位变大,分离性能增加,亲水性变好,通量增大.
关键词:
聚乙烯亚胺
,
聚乙烯醇
,
纳滤膜
雷海波
,
高保娇
,
申艳玲
应用化学
doi:10.3969/j.issn.1000-0518.2007.05.020
通过γ-氯丙基三甲氧基硅烷的偶联,将聚乙烯亚胺(PEI)偶合接枝在硅胶微粒表面,制得了对胆红素具有强吸附性能且可经酸碱处理重复使用的复合型吸附材料.结果表明,PEI大分子链中大量质子化的胺基氮原子与胆红素分子中电离的羧基之间产生的静电相互作用使PEI/SiO2对胆红素有吸附作用.考察了介质pH值、离子强度及PEI在复合材料PEI/SiO2的键合量对胆红素吸附容量的影响.静态吸附实验结果表明,硅胶表面的PEI对胆红素具有强的吸附能力,等温吸附满足Freundlich吸附方程,当胆红素初始质量浓度为0.590 g/L时,平衡吸附量可达13.17 mg/g;在近中性(pH=6)溶液中,复合吸附材料PEI/SiO2对胆红素吸附能力最强;在酸性溶液中,由于胆红素的羧基电离度较小,PEI/SiO2对胆红素的作用力较弱;在碱性溶液中,虽然胆红素的羧基电离度较大,但由于PEI的胺基氮原子质子化程度变小,PEI/SiO2与胆红素之间的作用力较弱.由于静电屏蔽作用,离子强度在很大程度上影响PEI/SiO2对胆红素的吸附容量.
关键词:
胆红素
,
吸附材料
,
聚乙烯亚胺
,
静电相互作用
,
吸附作用
WEI Yong-Hui
,
陈彪
应用化学
doi:10.3969/j.issn.1000-0518.2008.08.023
在380℃下熔融挤出制得聚醚醚酮酮(PEEKK)与聚醚酰亚胺(PEI)共混物.采用差示扫描量热仪(DSC)、广角X射线衍射仪(WAXD)和万能力学试验机研究了共混物的相容性、结晶行为和力学性能.结果表明,PEEKK/PEI共混体系为相容体系.其Tg组成的关系符合Fox方程.随共混体系中PEI用量的增加,共混物的冷结晶温度从208℃升至280℃.熔体降温结晶温度从315℃降至260℃,熔融温度从363℃降至322℃,熔融焓在-31.5～-2.2 J/g之间变化.共混物基本保持了PEEKK的力学性能,断裂伸长率随着PEI用量的增加从25%增加到60%,说明PEI对PEEKK有增韧作用.
关键词:
聚醚醚酮酮(PEEKK)
,
聚醚酰亚胺(PEI)
,
相容性
,
共混物
,
力学性能
Ping Dong
材料科学技术（英文）
Biomedical molecule has received extensive application in surface modification coating. In this paper, polyethyleneimine (PEI)/heparin coating and chitosan/heparin coating on NiTi alloy substrates were prepared by layer-by-layer method, and differences of corrosion behavior and biocompatibility of the coatings were studied. Static contact angles and Fourier transform infrared (FT-IR) test were used to analysis the surface morphology and structure character of the materials, and atomic absorption spectrum was used to verify the corrosion behavior of the materials. Furthermore, hemolysis, dynamic clotting time and platelet binding test were utilized to investigate the biocompatibility of the materials. The results revealed that the blood compatibility of PEI/heparin coating is better than that of the chitosan/heparin coating as well as the substrate.
关键词:
Biocompatibility
,
null
,
null
,
null
,
null
陈剑
,
李继定
,
亓荣彬
,
叶宏
,
陈翠仙
膜科学与技术
doi:10.3969/j.issn.1007-8924.2009.04.007
以PEI超滤膜为支撑层,PEG为复合层,制备了PEG/PEI渗透汽化RCC汽油脱硫复合膜.通过傅立叶红外光谱仪对PEG/PEI复合膜表面进行了结构分析,考察了交联前后官能团的变化.通过扫描电子显微镜分析了复合膜表面和断面的形态.将制备的复合膜应用于正庚烷和噻吩体系,首先考察了膜的溶胀性和稳定性.研究了不同聚合物PEG浓度、交联剂浓度,交联温度和交联时间对分离性能的影响,从而得到最佳制膜条件.
关键词:
渗透汽化
,
汽油脱硫
,
PEG/PEI复合膜
,
正庚烷/噻吩
