石墨烯基SnO_x-Sn气体传感器灵敏度影响因素研究

为提高本征石墨烯的气敏特性,将锡和氧化锡薄膜蒸镀在气相沉积法制备的石墨烯表面,制成石墨烯基SnO_x-Sn气体传感器,通过原子力显微镜(AFM)、场发射扫描电镜(FESEM)对其表面结构进行表征。并测试了其在室温下对低体积分数甲醛和二氧化氮(NO_2)气体的响应特性。研究并分析了膜蒸发速率、基底加热时间、氧气流量对传感器响应灵敏度的影响。     

固体超强酸SO42-/SnO2-Al2O3的制备及结构表征

采用共沉淀法制备了固体超强酸SO42-/SnO2-Al2O3.通过XRD、BET、FT IR、TG等手段对其结构进行了表征,将其用于苯甲醚的苯甲酰化反应初步研究了其催化性能.XRD结果表明,在催化剂最佳性能的活化温度500 ℃时,样品结晶不完全,随着锡铝原子摩尔比的增加,表面主要显现四方晶型的二氧化锡:在锡铝摩尔比为9∶1时,随着活化温度的提高,结晶逐渐趋于完善,结合FT IR结果可知,在700 ℃以上样品表面结合硫酸根已基本分解完毕.BET结果表明,引入铝可以增加SO42-/SnO2的比表面积,随着活化温度的提高,样品的比表面积呈现先上升后下降的趋势,在最佳性能活化温度时达到最大值.FT IR结果显示,表面硫酸根是以螯合和桥式两种方式和锡配位结合,但是起催化活化中心的大部分是和硫酸根以螯合双齿结合的锡.     

纳米氧化锡粉体的制备及性能表征

以SnCl4.5H2O为主要原料,以十六烷基铵为分散剂,NH3.H2O作为沉淀剂,利用液相沉积法成功制备出了SnO2纳米颗粒。通过透射电镜（TEM）、X射线衍射（XRD）以及热重分析（TG）,研究了纳米氧化锡粉体的形貌、尺寸分布和结构特征。SnO2颗粒平均粒径在30nm左右,呈不规则多面体,有些近似于球形,粒径分布窄,分散性良好。通过表征发现,SnO2纳米粉体的尺寸受几种反应因素的影响。     

Effects of SnO on structure and properties of borosilicate glasses

Tin was found in the bottom of float borosilicate glasses. To simulate the enriched amounts of SnO found on the surface of the float borosilicate glasses, a series of glasses were produced in which the stannous concentration was varied from 0.1 wt% to 9.0 wt%, while the relative concentration of other components were held constant. Infrared spectra were obtained to probe the effect of increased amounts of SnO on the structure of the glass samples. The results show that SnO plays the role of an intermediate in glasses studied. When FO/SnO〉1.0, SnO takes the role of network-former. And when FO/SnO〈1.0, SnO can give the free oxygen as network-modifier. Besides, SnO has intensive effect on thermal performance of borosilicate glasses.     

二丁基二硫代氨基甲酸铋的抗氧协同性能

为研究有机铋添加剂的抗氧化性能及与传统抗氧剂复配后的抗氧协同作用,采用薄层油膜微氧化实验考察二丁基二硫代氨基甲酸铋(Bi DDC)与p,p-二异辛基二苯胺(DODPA)在聚-α-烯烃(PAO)合成基础油和150SN矿物基础油中的抗氧协同作用,借助红外光谱定量分析基础油在不同氧化时间下的氧化程度,探讨Bi DDC与DODPA的抗氧协同机制。结果表明:Bi DDC自身具有一定的抗氧化性能,与DODPA复配后,Bi DDC可以起到消除自由基和分解氢过氧化物的作用,可使润滑油中的氢过氧化物分解,而芳胺抗氧剂能够捕捉自由基,控制氧化链的生长;Bi DDC和DODPA复配后,能够降低添加剂的用量,提升润滑油的抗氧化能力,表现出了良好的抗氧协同性能。     

Preparation and application of pharmaceutical wastewater treatment by praseodymium doped SnO2/Ti electrocatalytic electrode

Praseodymium was selected as a promoter for SnO2/Ti electrode to improve the electrocatalytic performance by electrodeposition in pharmaceutical wastewater treatment; the micrograph and the structure were characterized by SEM and XRD. Mixture uniform design was used in the optimization of the electrolytic conditions; mathematical model was established according to the rate of wiping COD off, which revealed the relationship between the current intensity, time of electrolysis, the amount of doped Pr, and the ratio of area （SnOJTi：Al）. On the basis of the analysis of the empirical model, the optimized parameters had been obtained; the rate of wiping COD off was up to 94.9%, it decreased from 392 to 20 mg/L. Experimental results showed that the electrocatalytic performance of the electrode doped with Pr was superior for the treatment of pharmaceutical wastewater.     

流态化CVD技术制备超细Al_2O_3-SnO_2复合粒子的过程机理

以SnCl_4-H_2O-N_2作为实验体系,采用流态化CVD技术制备了超细Al_2O_3-SnO_2复合粒子.利用透射电子显微镜(TEM)、X荧光光谱仪(XRF)、高分辨电子显微镜(HREM)等现代测试手段考察了SnO_2在Al_2O_3表面的分散形态及操作参数对SnO_2成膜与成核的影响.讨论了化学气相包覆过程机理.     

热处理温度对氧化锡气敏特性的影响

利用硝酸氧化法、化学沉淀法合成了纳米ＳｎＯ２及贵金属掺杂ＳｎＯ２材料,并对合成材料进行了物相表征和气体灵敏度测量．结果表明：在４００℃～９００℃热处理温度范围内,ＳｎＯ２的平均晶粒度随处理温度升高而增大,但均＜４０ｎｍ;纯ＳｎＯ２材料的气体灵敏度随平均晶粒度的增大而减小,主要受尺寸效应控制,而贵金属掺杂ＳｎＯ２的气体灵敏度受尺寸效应和催化效应共同控制;通过控制掺杂和热处理温度可改善ＳｎＯ２的气敏性能,实现对可燃气体的普敏检测或选择性检测     

二丁基镁制备β-丁内酯与ε-己内酯共聚物的结构与性能EI北大核心

以无毒性的二丁基镁为催化剂催化β-丁内酯和ε-己内酯本体开环共聚合,制备了一系列不同单体配比的共聚物。核磁共振碳谱分析了共聚物微观结构,计算了各单元平均序列长度,共聚物组成显著影响单元序列长度。酯交换反应使得单元序列结构重新分布并趋向于无规分布,但没有达到完全无规化分布。差示扫描量热仪和X射线衍射仪分析了共聚物的热性能和结晶性,表明共聚物热性能和结晶性依赖于共聚物组成和单元序列长度。