纳米金修饰硅纳米线电极阳极溶出法测定痕量铅、铜

以浸入沉积的方法在硅纳米线上修饰了金纳米颗粒,并通过电子扫描显微镜（SEM）和X射线荧光分析（XRF）对金纳米粒子修饰的硅纳米线电极表面形貌进行了表征.以修饰后的硅纳米线电极作为工作电极,采用阳极溶出法检测水中痕量铅和铜,考察pH值、富集电位和富集时间对溶出峰的影响,优化出最佳实验条件.在优化的实验条件下,铅Pb2＋和铜Cu2＋的灵敏度分别为0.649μA/（μg.L-1）和0.177μA/（μg.L-1）.检测极限达到0.26μg.L-1和0.67μg.L-1.峰电流与离子浓度在质量浓度25~200μg.L-1的范围内形成良好的线性关系.     

不同变质剂对4032铝合金变质效果的影响

研究Sr与不同变质剂复合添加对4032铝合金组织及性能的影响.通过组织观察、扫描电镜观察、能谱分析和力学性能测试发现:在几种不同的变质体系中,Sr与Na盐复合变质后的组织和性能最好;Sr+其他元素复合变质的针孔率低于Sr单独变质处理的针孔率,其中以Sr+Na盐变质的针孔率最低;共晶型铝硅合金添加Sr和Na变质组织呈亚共晶状态,而经P变质后组织呈过共晶状态.     

Tunable water-based lubrication behavior of alkyl- and fluoroalkyl-silanes

In this paper,we report the tribological properties of self-assembled molecular(SAM) films of fluoroalkylsilanes and non-fluoroalkylsilanes,with different chain-lengths,adsorbed on Si substrate surfaces by covalent bonds.The SAM films were characterized using a universal ball-disk experimental tester in aqueous solutions.The substrate surface was examined by X-ray photoelectron spectroscopy(XPS),and the SAM films adsorbed on the Si surfaces were inspected by contact angle measurements and XPS.Lubrication studies revealed that several kinds of fluoroalkylsilanes had similar friction coefficients;the small differences were attributed to the chain flexibility.In contrast,differences in the aqueous lubrication properties of SAM films of non-fluoroalkylsilanes were clearly identified.It is suggested that substitution with fluorine atoms and the surface affinities of fluoroalkylsilanes contributed to redistribution of surface changes,causing variations in lubrication behaviors.     

SiCl_4制备正硅酸乙酯的工艺研究

为寻找一条工序简单、耗价低、易于工业放大路线,实现多晶硅副产物四氯化硅(SiCl4)废物资源化制备正硅酸乙酯(TEOS),本文以多晶硅副产物SiCl4和无水乙醇为原料制备TEOS,在半连续化生产工艺的基础上研究了SiCl4与乙醇的摩尔比、反应温度、反应时间等因素对TEOS产率及纯度的影响。正交实验优化结果表明:15℃下,以恒定速率滴加14.21 g无水乙醇于15 g四氯化硅中,反应35 min,补加8.12 g无水乙醇;55℃下恒温40 min,经减压蒸馏,除去低沸点的乙醇和氯化氢,TEOS产率达到86.61%。对正交实验优水平下制得的产物进行红外光谱(IR)和气相色谱(GC)分析,结果表明:产物中TEOS结构正确,其纯度大于99.0%,达到市售分析纯纯度。     

Design of radiation hard phase-locked loop at 2.5 GHz using SOS-CMOS

Abstract: A radiation hard phase-locked loop (PLL) is designed at 2.5 GHz using silicon on sapphire complementary metal-oxide-semiconductor process. Radiation hardness is achieved through improving circuit design without sacrificing real estate. Stability is guaranteed by a fully self-bias architecture. The lock time of PLL is minimized by maximizing the loop bandwidth. Frequency tuning range of voltage controlled oscillator is significantly enhanced by a novel load configuration. In addition, multiple bias stages, asynchronous frequency divider, and silicon on sapphire process jointly make the proposed PLL more radiation hard. Layout of this PLL is simulated by Cadence Spectre RF under both single event effect and total induced dose effect. Simulation results demonstrate excellent stability, lock time < 600 ns, frequency tuning range [1.57 GHz, 3.46 GHz], and jitter < 12 ps. Through comparison with PLLs in literatures, the PLL is especially superior in terms of lock time and frequency tuning range performances.     

溶胶-凝胶法制备(Bi, Nd)4Ti3O12铁电薄膜

采用溶胶凝胶法在Pt/Ti/SiO2/Si基片上制备了(Bi, Nd)4Ti3O12铁电薄膜.将薄膜分别进行每一层、每二层、每三层500 ℃空气中预退火10 min，分别称为样品a、b、c，最后都于氮气氛中680℃总退火半小时. 结果表明预退火工艺对薄膜的铁电性能影响很大.样品a、b的铁电性能(2Pr分别为47.8 μC/cm2和51.9 μC/cm2)远远高于样品c(2Pr = 28.7 μC/cm2).三组薄膜都呈现良好的抗疲劳特性.     

高骨架填充率的SiO2有序大孔材料的制备

以SiO2有序大孔材料制备作为研究对象,系统考察了胶晶模板法中影响前驱物填充率的诸因素,包括填充方法、填充时间和填充次数.研究表明,直接浸渍法易导致大孔结构的收缩、脱落和表面覆盖.本文提出的在模板表面添加盖片再填充的方法有效解决了上述问题.当填充时间为5 min、填充次数为两次时,SiO2有序大孔材料的骨架填充率较高.扫描显微镜(SEM)和分光光度计的表征结果证实,实验成功制备了填充率高达22.53%的大面积SiO2有序大孔材料.     

CHF3／DMCPS比对F掺杂SiCOH薄膜结构及性能的影响

研究了用十甲基环五硅氧烷和三氟甲烷电子回旋共振等离子体沉积的掺FSiCOH低k薄膜中，CHF，／DMCPS比对薄膜结构、成分、介电性能、热稳定性和憎水性的影响．结果表明，随着CHF，／DMCPS比的增大，沉积的薄膜从SiCOH向F-SiCOH和a—C：F：H转变．对于F-SiCOH薄膜，在获得较低介电常数的前提下，薄膜热稳定性和憎水性得到改善．     

闪速燃烧合成的Fe-Si3N4中FexSi粒子的形成机理

采用SEM、EDS等手段研究了闪速燃烧合成的氮化硅铁及其原料FeSi75的组成、结构,并结合闪速燃烧合成工艺和热力学分析,揭示氮化硅铁中FexSi粒子的形成机理.结果表明:在以74μm的FeSi75氮化制备氮化硅铁过程中,金属硅和ξ(FeSi2.3)相中部分硅氮化为氮化硅,而氮化硅铁中FexSi粒子则来源于ξ相的氮化;当ξ相被氮化到其中的[Si]摩尔分数降低近25%时,[Si]的活度aSi趋于0,氮化趋于平衡,ξ相中不能被继续氮化的部分即为FexSi粒子,其Fe∶Si原子比例大约为3∶1;FexSi粒子的大小、均匀分布状况与ξ相颗粒粒径大小及分布状况有关.     

Preparation and kinetic analysis of Li4SiO4 sorbents with different silicon sources for high temperature CO2 capture

Using diatomite and analytical pure SiO2 as silicon sources,Li4SiO4 sorbents for high temperature CO2 capture were prepared through solid-state reaction method.Phase composition was analyzed by X-ray diffraction,and the CO2 absorption capacity and absorptoin-desorption performance were studied by the simultaneous thermal thermogravimetric analyzer(TG-DSC).The results showed that silicon source had an important influence on CO2 absorption properties.The kinetic parameters for the chemisorption and diffusion processes were obtained by the isothermal study for different silicon sources.The results showed that the activation energies for these two processes were estimated to be 105.427 and 35.928 kJ/mol for the sample with analytical pure SiO2(AS).While for the sample with diatomite(DS),the activation energies for these two processes were estimated to be 78.500 and 20.439 kJ/mol,respectively.