低比电阻Si—Ti—C—O纤维先驱体的合成

通过液体聚硅烷（ Ｌ Ｐ Ｓ） 与钛酸四丁酯 Ｔｉ （ Ｏ Ｂｕ）４ 反应合成了不同钛含量的聚钛碳硅烷先驱体,经熔融纺丝、不熔化处理及高温烧结等工艺制备出比电阻为１０６ ～１０３ Ω·ｃｍ 的 Ｓｉ Ｔｉ Ｃ Ｏ 纤维． 用 Ｉ Ｒ、 Ｇ Ｐ Ｃ、 Ｖ Ｐ Ｏ、 Ｔ Ｇ、 Ｄ Ｔ Ａ 等方法分析研究了聚钛碳硅烷的组成、结构与特性及其与含钛量的关系     

富碳含钛碳化硅纤维的研制

以聚硅烷（ＰＳ）,聚氯乙烯（ＰＶＣ）和钛酸四丁酯（Ｔｉ（ＯＢｕ）４）合成含碳量不同的聚钛碳硅烷（ＰＴＣ）先驱体,经熔融纺丝、不熔化处理、高温烧成制备出具有较好工艺性能和电阻率为１０＾３Ω．ｃｍ～１０＾０Ω．ｃｍ的富碳含钛碳化硅纤维（Ｓｉ－Ｔｉ－Ｃ－Ｏ纤维）。运用ＩＲ、ＧＰＣ、ＶＰＯ待分析手段系统地研究了富碳ＰＴＣ先驱体的合成,讨论了含碳量对纤维的制备工艺及纤维性能的影响。     

Ti(OC4H9)4-MAPS体系溶胶-凝胶转变研究

研究了Ｔｉ（ＯＣ４Ｈ９）４－ＭＡＰＳ体系中Ｔｉ（ＯＣ４Ｈ９）４、ＭＡＰＳ、Ｃ２Ｈ５ＯＨ、Ｈ２Ｏ４个原料组分对聚钛硅氧烷产转变规律的影响。结果表明,增大水和Ｔｉ（ＯＣ４Ｈ９）４的用量或降低ＭＡＰＳ和Ｃ２Ｈ５ＯＨ的用量,菜成凝胶;反之,则易形成溶胶。     

溶胶—凝胶法制备有机改性SiO2—TiO2涂层的研究

用溶胶－凝胶法在ＰＭＭＡ上制得ＳｉＯ２－ＴｉＯ２涂层。溶胶粘度分析表明，溶胶以线性生长方式凝胶，适宜于制备薄膜。ＦＴＩＲ对涂层的干燥和热处理过程研究表明，涂层中形成Ｓｉ－Ｏ－Ｔｉ－Ｏ－Ｓｉ无机网络结构。扫描电镜对涂层中Ｔｉ－Ｓｉ元素的分布进行了能谱分析，发现无机网络主要分布于涂层的表面及界面处。     

可用于 a-Si∶H 太阳电池的钛硅化物的研究

用直流溅射法在ＩＴＯ玻璃衬底上溅射金属Ｔｉ膜后再用辉光放电法沉积ａ－Ｓｉ，研究了钛的硅化物的形成，利用ＸＰＳ、ＲＢＳ分析，确定了反应生成物为ＴｉＳｉ２，且生成物十分有效地阻挡了ＩＴＯ中的Ｉｎ的扩散；用ＵＳ／ＶＩＳ分光光度计测量了生成物的透过率发现其透过率在紫外部分较ＩＴＯ膜提高；测试了Ｔｉ／ａ－Ｓｉ界面的Ｉ－Ｖ特性，发现界面无势垒；测量了生成物的电阻率，数量级为几十μΩ·ｃｍ数量级。该钛的硅化物膜可用于非晶硅太阳电池的前电极。     

可用于a—Si：H太阳电池的钛硅化物的研究

用直流溅射法在ＩＴＯ玻璃衬底上溅射金属Ｔｉ膜后用辉光放电法沉积ａ－Ｓｉ，研究了钛硅化物的形成，利用ＸＰＳ，ＲＢＳ分析，确定了反应生成物为ＴｉＳｉ２，且生成物十分有效地阻挡了ＩＴＯ中的Ｉｎ的扩散；用ＵＳ／ＶＩＳ分光光度计测量了生成物的透射率发现其透过率在紫外部分较ＩＴＯ膜提高；测试了Ｔｉ／ａ－Ｓｉ界面的Ｉ－Ｖ特性，发现界面无势垒；测量了生成物的电阻率，数量级为几十μΩ．ｃｍ数量级。该钛的硅化物膜要用     

Sol—Gel法制备TiO2／PVP复合材料及其显微硬度研究

以钛酸丁酯和聚乙烯吡咯烷酮（ＰＶＰ）为原料,采用Ｓｏｌ－Ｇｅｌ法制备了ＴｉＯ２／ＰＶＰ纳米复合材料。     

溶胶-凝胶法制备TiO2复合陶瓷光催化膜--制备前驱物对膜性质的影响

利用溶胶－凝胶法分别以异丙醇钛和ＴｉＣｌ４为原料制备两种不同的二氧化钛溶胶,浸涂在陶瓷膜上,形成ＴｉＯ２复合陶瓷光催化膜。通过应用ＱＥＬＳ、ＸＲＤ、ＢＥＴ、ＳＥＭ、ＵＶ－ｖｉｓ和荧光光谱等方法考究溶胶制备的前驱液对膜制备过程中的化学物理性质,膜结构和光学笥质的影响,发现由异丙醇然制备的溶胶粒度小而均一,能够在陶瓷基膜上可以形成致密的孔分布的一窄小的ＴｉＯ２膜,并且其吸收光谱和荧光光谱发生“蓝移”现     

TiO2-SiO2复合半导体气凝胶制备及光催化活性研究

ＴｉＯ２－ＳｉＯ２复合半导体气交是一种新型纳米光催化氧化剂。本文以正硅酸乙酯、钛酸丁酯为原料,用溶胶－凝胶法经超临界干燥制备出了ＴｉＯ２－ＳｉＯ２复合半导体气凝胶。研究了ＴｉＯ２：ＳｉＯ２不同配比对溶胶－凝胶过程的影响;用ＢＥＴ、ＸＲＤ、ＳＥＭ、ＴＥＭ等测试方法对其结构进行了表征;以苯酚为探针考察了ＴｉＯ２－ＳｉＯ２复合半导体气凝胶的光催化氧化活性,并与普通锐钛矿型钛白粉光催化剂进行了对比结果表明     

TiO2／SnO2超微粒及其复合LB膜的紫外—可见光吸收光谱的研究

用胶体化学方法制备ＴｉＯ２／ＳｎＯ２超微粒,ＴｉＯ２／ＳｎＯ２超微粒及其复合ＬＢ膜的紫外－可见光吸收光谱研究表明：ＴｉＯ２／ＳｎＯ２超微粒具有量子尺寸效应使吸收光谱发生“蓝移”;ＴｉＯ２／ＳｎＯ２超微粒／硬脂酸复合ＬＢ膜具有良好的抗紫外性能和光学透过性能。     

温度场和电场调控硅基反铁电厚膜相变电流特性研究

采用溶胶-凝胶技术,在Pt(111)/Ti/SiO2/Si衬底上制备了高(100)取向生长、表面平整且结构致密的(Pb,La)(Zr,Ti)O3反铁电厚膜,研究了温度场和电场对(Pb,La)(Zr,Ti)O3反铁电厚膜电学性能的影响。实验结果表明反铁电厚膜在温度场和电场作用下发生反铁电相、铁电相和顺电相的相互转变,随外加电场增加,反铁电-铁电相变温度逐渐减小,介电常数峰值由2410减小到662,相变电流密度值由2.21×10-7A/cm2增大到8.52×10-7 A/cm2;随外加温度场增加,反铁电-铁电相变电场强度逐渐减小,饱和极化强度由39μC/cm2减小到31μC/cm2,相变电流密度值由2.89×10-5 A/cm2减小到8.8×10-6 A/cm2,温度场和电场可实现对反铁电厚膜相变电流效应的有效调控。     

Effect of Bi2Ti2O7 Seeding Layer on Capacitance-voltage Properties of Bi3:54Nd0:46Ti3O12 Films

Au/Bi3:54Nd0:46Ti3O12/Bi2Ti2O7/Si structure has been fabricated with a preferentially (111)-orientated Bi2Ti2O7 seeding layer as a ferroelectric gate of metal-ferroelectric-insulator ¯eld e®ect transistor. Bi3:54Nd0:46Ti3O12 and Bi3:54Nd0:46Ti3O12/Bi2Ti2O7 ¯lms are both well-crystallized when annealed at 680±C for 40 min, and have smooth, dense and crack-free surfaces. The width of memory window of the ferroelectric gate increases with increasing electric ¯eld applied to the Bi3:54Nd0:46Ti3O12 thin ¯lms. The width of memory window of Au/Bi3:54Nd0:46Ti3O12/Bi2Ti2O7/Si with seeding layer is relatively wider than that of Au/Bi3:54Nd0:46Ti3O12/Si at the same bias voltage, and the counterclockwise hysteresis curve of Au/Bi3:54Nd0:46Ti3O12/Bi2Ti2O7/Si is referred to as polarization type switching at di®erent voltages. Bi2Ti2O7 seeding layer plays an important role in alleviating the element interdi®usion between Bi3:54Nd0:46Ti3O12 and Si.     

低电阻率Si-C-O纤维组成和性能

采用聚二甲基硅烷（PDMS）与不同比例的聚氯乙烯（PVC）共裂解合成制备了低电阻率Si-C-O纤维先驱体聚合物。经熔融纺丝、空气不熔化处理及高温烧成制成低电阻率Si-C-O纤维。通过元素分析、XRD及XPS研究了纤维组成及其结构,考察了纤维组成与性能的关系。结果表明,PVC的掺入使烧成纤维中氧含量降低,游离碳的含量有较大幅度的增加,纤维的密度和模量下降,在较低的Si/C比时,纤维的强度同碳含量没有明显的关系。     

Resistive-switching behavior in polycrystalline CaCu(3)Ti(4)O(12) nanorods

Highly aligned CaCu(3)Ti(4)O(12) nanorod arrays were grown on Si/SiO(2)/Ti/Pt substrates by radio-frequency sputtering at a low deposition temperature of 300 °C and room temperature. Structural and morphological studies have shown that the nanostructures have a polycrystalline nature and are oriented perpendicular to the substrate. The high density of grain boundaries in the nanorods is responsible for the nonlinear current behavior observed in these arrays. The current-voltage (I-V) characteristics observed in nanorods were attributed to the resistive memory phenomenon. The electrical resistance of microcapacitors composed of CaCu(3)Ti(4)O(12) nanorods could be reversibly switched between two stable resistance states by varying the applied electric field. In order to explain this switching mechanism, a model based on the increase/decrease of electrical conduction controlled by grain boundary polarization has been proposed.     

High temperature stability of multicomponent TiAlSiN and CrAlSiN coatings

The high temperature oxidation behavior of TiAlSiN and CrAlSiN coatings was studied. These coatings were deposited on silicon substrates by using a cathodic-arc deposition system with lateral rotating arc cathodes. Titanium, chromium and Al88Si12 cathodes were used for the deposition of TiAlSiN and CrAlSiN coatings. All the deposited Ti(0.49)Al(0.44)Si(0.07)N, Ti(0.41)Al(0.51)Si(0.08)N and Cr(0.50)Al(0.440Si(0.06)N coatings showed B1-NaCl crystal structure and possessed nano-grain sizes of 6-8 nm. For the high temperature oxidation test, the coated samples were annealed at 900 degrees C in air for 2 hours. The Ti(0.41)Al(0.51)Si(0.08)N with higher Al and Si contents possessed lower oxidation rate than that of Ti(0.49)Al(0.44)Si(0.07)N. The oxide layer formed on the Ti(0.49)Al(0.44)Si(0.07)N coatings consisted of large TiO2 and TiAlSiN grains at the oxide-coating interface, followed by a layer of Al2O3 in the near-surface region. The oxidation rate of the Cr(0.50)Al(0.44)Si(0.06)N coated sample was much lower than that of the Ti(0.49)Al(0.44)Si(0.07)N and Ti(0.41)Al(0.51)Si(0.08)N. The dense Al2O3 with amorphous top layer at the oxide-coating interface retarded the diffusion of oxygen into the Cr(0.50)Al(0.44)Si(0.06)N. The deposited Cr(0.50)Al(0.44)Si(0.06)N showed a high temperature performance superior to those of the Ti(0.49)Al(0.44)Si(0.07)N and Ti(0.41)Al(0.51)Si(0.08)N.     

Effect of surface modification of bamboo cellulose fibers on mechanical properties of cellulose/epoxy composites

Bamboo cellulose fibers were treated with NaOH aqueous solution and silane coupling agent, respectively, before they were applied into epoxy composites. The effect of surface modification on mechanical properties was evaluated by tensile and impact tests under controlled conditions. Compared with the untreated cellulose filled epoxy composites, the NaOH solution treatment increased the tensile strength by 34% and elongation at break by 31%. While silane coupling agent treatment produced 71% enhancement in tensile strength and 53% increase in elongation at break. The scanning electron microscopy (SEM) was used to observe the surface feature of the cellulose fibers and the tensile fractures as well as cryo-fractures of the composites. The Fourier transform infrared (FTIR) was employed to analyze the chemical structure of the cellulose fibers before and after modifications. The results indicated different mechanisms for the two modifications of cellulose. The NaOH solution partly dissolved the lignin and amorphous cellulose, which resulting in splitting the fibers into smaller size. This led to easier permeating into the gaps of the fibers for epoxy resin (EP) oligmer and forming effective interfacial adhesion. Based on the emergence of Si–O–C and Si–O–Si on the cellulose surface, it was concluded that the enhancement of mechanical properties after coupling agent modification could be ascribed to the formation of chemical bonds between the cellulose and the epoxy coupled with the coupling agent.     

Ag/Bi4Ti3O12/p-Si异质结的制备及其C-V特性研究

为制备符合铁电存储器件要求的高质量铁电薄膜,采用溶胶-凝胶(Sol-Gel)工艺,制备了Si基Bi4Ti3O12铁电薄膜及MFS结构的Ag/Bi4Ti3O12/P-Si异质结,对Bi4Ti3O12薄膜的相结构特征及异质结的C-V特性进行了测试与分析.XRD图谱显示,Si基Bi4Ti3O12薄膜具有沿c-轴择优取向生长的趋势,而Ag/Bi4Ti3O12/p-Si异质结顺时针回滞的C-V特性曲线则表明,该异质结可实现电极化存储.此外,对该异质结C-V特性曲线的非对称及向负偏压方向偏移的产生原因也进行了分析.在此基础上,为提高铁电薄膜的铁电性能及改善其C-V特性提出了合理的结构设想.     

Thermal Oxidation of Ti and Pb Thin Films Deposited on Single-Crystal Silicon

Thin Pb–Ti–O films on single-crystal Si were prepared by magnetron sputtering followed by thermal oxidation of Pb/Ti/Si and Ti/Pb/Si structures. Oxidation of Pb/Ti bilayers was found to yield lead oxides, which then react with Ti to form lead titanate. Ti/Pb bilayers on Si could be converted into stoichiometric lead titanate, through titanium and lead oxides, by oxidation between 870 and 1070 K. Some of the films exhibited ferroelectric properties.     

Grafting of nano-TiO2 onto flax fibers and the enhancement of the mechanical properties of the flax fiber and flax fiber/epoxy composite

In this article, a flax fiber yarn was grafted with nanometer sized TiO₂, and the effects on the tensile and bonding properties of the single fibers and unidirectional fiber reinforced epoxy plates were studied. The flax fiber yarn was grafted with nanometer sized TiO₂ through immersion in nano-TiO₂/KH560 suspensions under sonification. The measured grafting content of the nano-TiO₂ ranged from 0.89 wt.% to 7.14 wt.%, dependent on the suspension concentration. With the optimized nano-TiO₂ grafting content (∼2.34 wt.%), the tensile strength of the flax fibers and the interfacial shear strength to an epoxy resin were enhanced by 23.1% and 40.5%, respectively. The formation of Si–O–Ti and C–O–Si bonds and the presence of the nano-TiO₂ particles on the fiber surfaces contributed to the property enhancements. Unidirectional flax fiber reinforced epoxy composite (V_f = 35.4%) plates prepared manually showed significantly enhanced flexural properties with the grafting of nano-TiO₂.     

The influences of rapid-thermal annealing on the characteristics of Sr0.6Ba0.4Nb2O6 thin film

The Sr0.6Ba0.4Nb2O6 (SBN) thin films were successfully prepared on Pt/Ti/Si and SiO2/Si/Al substrates and crystallized subsequently using rapid thermal annealing (RTA) process in ambient atmosphere for 1 min. The surface morphologies and thicknesses of as-deposited and annealed SBN thin films were characterized by field emission scanning electron microscopy, and the thickness was about 246 nm. As compared with the as-deposited SBN thin films, the RTA-treated process had improved the crystalline structures and also had large influence on the crystalline orientation. When the annealing temperatures increased from 700 degrees C to 900 degrees C, the diffraction intensities of (410) and (001) peaks apparently increased. Annealed at 900 degrees C, the (001) peak had the maximum texture coefficient and SBN thin films showed a highly c-axis (001) orientation. The influences of different RTA-treated temperatures on the polarization-applied electric field (P-E) curves and the capacitance-voltage (C-V) curves were also investigated.