Ba1—xSrxTiO3薄膜的制备及特性研究

用溶胶－凝胶方法制备Ｂａ１－ｘＳｒｘＴｉＯ３（ＢＳＴ）薄膜材料，研究薄的结构和电性能。用ＸＤＲ及ＳＥＭ分析了沉积在硅片上的ＢＳＴ薄膜的结构，测试了在室温下ＢＳＴ薄膜的电滞回线及介电特性。     

Sr1-xBixFeO3-δ(x≤0.50)的柠檬酸盐法制备和导电性

采用柠檬酸法制备了Ｓｒ１－ｘＢｉｘＦｅＯ３－δ（ｘ≤０．５０）系列氧离子－电子混合导体,并采用ＸＲＤ,ＩＲ,ＴＧ,ＤＴＡ和交流复阻抗技术对产物进行了表征。初始凝胶经自燃和８００℃下预烧,可得纯相钙钛矿产物粉体,其结构与ＳｒＦｅＯ３相似,为正交对称性。     

Sol-Gel法制备BaxSr1-xTiO3铁电薄膜化学机制的探讨

用ＦＴＩＲ分析,结合ＤＳＣ、ＸＲＤ、ＡＦＭ实验结果,展示了ｓｏｌ－ｇｅｌ法制备ＢａｘＳｒ１－ｘＴｉＯ３（ＢＳＴ）薄膜热演化过程的化学机制,研究表明：螯合剂ＨＡｃＡｃ的引入减缓钛醇盐水解速率、改善晶化途径、降低结晶起始温度,从而制得了晶化完善、致密无裂纹的ＢＳＴ薄膜。     

Sol-Gel法制备 BaxSr1-xTiO3铁电薄膜化学机制的探讨

用ＦＴＩＲ分析,结合ＤＳＣ、ＸＲＤ、ＡＦＭ实验结果,展示了ｓｏｌ－ｇｅｌ法制备ＢａｘＳｒ１－ｘＴｉＯ３（ＢＳＴ）薄膜热演化过程的化学机制．研究表明：螯合剂ＨＡＣＡＣ的引入减缓钛醇盐水解速率、改善晶化途径、降低结晶起始温度,从而制得了晶化完善、致密无裂纹的ＢＳＴ薄膜．     

CSF－1R部分基因在大肠杆菌中表达、抗融合蛋白血清制备及丝氨酸／苏氨酸磷酸化的初步研究

鼠巨噬细胞集落刺激因子－１受体（ｍＣＳＦ－１Ｒ）部分序列与质粒ｐＧＥＸ－２Ｔ谷胱苷肽转移酶（ＧＳＴ）融合，融合蛋白ＧＳＴ－ＣＤ－Ｐｓｔ（胞浆区），ＧＳＴ－ＣＴｅｒｍ（Ｃ－末端）和ＧＳＴ－ＫＩ（激酶插入区）成功地在大肠杆菌ＪＭ１０９株表达。初步结果指出：（１）ＧＳＴ－融合蛋白在体外激酶分析中可以作为底物；（２）由ＰＫＡ导致的磷酸化可能具有生理学意义；（３）ｍＣＳＦ－１Ｒ被ＣＫＩＩ磷酸化。３２Ｐ标记ＧＳＴ－ＣＤ－Ｐｓｔ的磷酸氨基酸分析证实，ｍＣＳＦ－１Ｒ的胞浆区丝氨酸上被磷酸化，已制备抗ＧＳＴ－ＣＴｅｒｍ，ＧＳＴ－ＫＩ和ＧＳＴ－ＣＤ－Ｐｓｔ兔抗体。抗血清的筛选通过野生型３２Ｄ－ＣＳＦ－１Ｒ转染子免疫沉淀进行。     

用柠檬酸盐-凝胶法低温合成单相Ba(Mg1/3Ta2/3)O3

本文利用ＸＴＤ、ＤＴＡ、ＴＧＡ、ＳＥＭ、ＴＥＭ等分析手段研究了用柠檬酸盐－凝胶法低温（６００℃）合成单相Ｂａ（Ｍｇ１／３Ｔａ２／３）Ｏ３的方法。结果发现，与传统的固相反应合成ＢＭＴ的方法相比，柠檬酸盐溶胶－凝胶法能在６００℃的温度下合成单相ＢＭＴ，睽怕粉体具有１０￣２０ｎｍ的单颗粒尺寸。     

La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_(3-α)的柠檬酸盐法制备和表征

采用柠檬酸盐法制备了　Ｌａ０．９Ｓｒ０．１Ｇａ０．８Ｍｇ０．２Ｏ３－α（ＬＳＧＭ）粉体材料．ＴＧ和　ＤＴＡ分析表明,凝胶在２６５～３０９℃下分解为相应的氧化物．ＸＲＤ测试表明,凝胶在１３００℃以上煅烧时,转变为简单立方钙钛矿结构的纯相产物．１４５０℃下烧结体的相对密度为８８％,其复阻抗特性表明产物中没有明显的晶界过程,且在８００℃下的电导率为 ２.１×１０－２Ｓｃｍ－１,活化能为０．９８ｅＶ．     

溶胶凝胶法制备Li4.5B0.5Si0.5O4-xLi2O导体材料及导电性能

采用溶胶－凝胶法制备了Ｌｉ４．５Ｂ ０．５Ｓｉ０．５Ｏ４－ｘＬｉ２Ｏ（ｘ＝０～０．５）离子导体材料,并采用ＤＴＡ－ＴＧ、ＸＲＤ、ＴＥＭ及交流阻抗等技术对样品进行了分析和测试,结果发现：溶胶－凝胶法可降低Ｌｉ４．５Ｂ０．５Ｓｉ０．５Ｏ４的合成温度;随Ｌｉ２Ｏ的掺入可增强基质材料的致密性并提高其离子的导电性能。     

Si-Zr-B复合非催化形核涂层壳型的制备

先采用熔模铸造中的制壳工艺,在壳型内壁制备了Ｓｉ－Ｚｒ－Ｂ基底涂层Ｚ,然后利用溶胶凝胶原理,经浸涂－分级热处理以及８５０℃玻璃热处理后,在Ｚ表面制备了七层与Ｚ同成分的Ｓｉ－Ｚｒ－Ｂ玻璃薄膜涂层。ＸＲＤ和ＳＥＭ分析结果表明,Ｈ３ＢＯ３的加入起抑制Ｓｉ－Ｚｒ－Ｂ涂层析晶及对涂层表面裂纹的高温自愈合作用。因此,将Ｚ－Ｒ壳型置于１５００℃保温３０ｍｉｎ后,涂层的析晶量仅为１％～３％,其结构在高温下具有很强的稳定性。过冷实验结果表明,ＤＤ３单晶高温合金可以在该涂层壳型内获得１４０Ｋ过冷度,证明Ｓｉ－Ｚｒ－Ｂ涂层具有良好的非催化形核惰性。     

溶胶－凝胶法制备SiO_2气凝胶及其特性研究

本文以ＴＥＯＳ为原料，采用溶胶－凝胶法和超临界干燥工艺制备了轻质纳米多孔材料ＳｉＯ２气凝胶．研究了溶剂用量及ｐＨ值对溶胶的凝胶化过程和最后制成的气凝胶的特性的影响．并用ＢＥＴ、ＸＲＤ、ＳＥＭ等实验手段研究了这些气凝胶的结构和一些基本物理现象．     

Structural and optical properties of AlxOy/Pt/AlxOy multilayer absorber

We report on the microstructure and optical properties of Al_xO_y–Pt–Al_xO_y interference-type multilayer films, deposited by electron beam (e-beam) deposition onto corning 1737 glass, silicon (1 1 1) and copper substrates. The structural properties were investigated by Rutherford backscattering spectrometry, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The optical properties were extracted from specular reflection/transmission, diffuse reflectance and emissometer measurements. The stratification of the coatings consists of a semi-transparent middle Pt layer sandwiched between two layers of Al_xO_y. The top and bottom Al_xO_y layers were non-stoichiometric with no crystalline phases present. The Pt layer is in the fcc crystalline phase with a broad size distribution and spheroidal shape in and between the rims of Al_xO_y. The surface roughness of the stack was found to be comparable to the inter-particle distance. The optical calculations confirm a high solar absorptance of ∼0.94 and a low thermal emittance of ∼0.06 for the multilayer stack, which is attributed not only to the optimized nature of the multilayer interference stacks, but also to the specific surface morphology and texture of the coatings. These optical characteristics validate the spectral selectivity of the Al_xO_y–Pt–Al_xO_y interference-type multilayer stack for use in high temperature solar-thermal applications.     

Optimization of AlxOy/Pt/AlxOy multilayer spectrally selective coatings for solar-thermal applications

Spectrally selective Al_xO_y/Pt/Al_xO_y multilayer absorber coatings were deposited onto corning 1737 glass, Si (111) and copper substrates using electron beam (e-beam) vacuum evaporator at room temperature. The employment of ellipsometric measurements and optical simulation was proposed as an effective method to optimize and deposit multilayer solar absorber coatings. The optical constants (n and k) measured using spectroscopic ellipsometry, showed that both Al_xO_y layers, which used in the coatings, were dielectric in nature and the Pt layer was semi-transparent. The optimized multilayer coatings exhibited high solar absorptance α ∼ 0.94 ± 0.01 and low thermal emittance ? ∼ 0.06 ± 0.01 at 82 °C. The Rutherford backscattering spectroscopy (RBS) data of Al_xO_y/Pt/Al_xO_y multilayer absorber indicated the Al_xO_y layers present in the coating were nearly stoichiometry. The scanning electron microscope analysis (SEM) result indicated that the average diameter and inter-particles distance of Pt grains were statistically about 146 ± 0.17 nm and 6-10 ± 0.2 nm respectively.     

Interfacial microstructure of NiSix/HfO2/SiOx/Si gate stacks

Integration of NiSi_x based fully silicided metal gates with HfO₂ high-k gate dielectrics offers promise for further scaling of complementary metal-oxide- semiconductor devices. A combination of high resolution transmission electron microscopy and small probe electron energy loss spectroscopy (EELS) and energy dispersive X-ray analysis has been applied to study interfacial reactions in the undoped gate stack. NiSi was found to be polycrystalline with the grain size decreasing from top to bottom of NiSi_x film. Ni content varies near the NiSi/HfO_x interface whereby both Ni-rich and monosilicide phases were observed. Spatially non-uniform distribution of oxygen along NiSi_x/HfO₂ interface was observed by dark field Scanning Transmission Electron Microscopy and EELS. Interfacial roughness of NiSi_x/HfO_x was found higher than that of poly-Si/HfO₂, likely due to compositional non-uniformity of NiSi_x. No intermixing between Hf, Ni and Si beyond interfacial roughness was observed.     

Tc trend in high-Tc superconductors

In our previous works, we have shown that most existing ceramic superconductors can be considered to be built of superconductor-semiconductor composite and we have estimated the change in phonon spectrum of the intrinsic superconductor unit if a semiconductor unit is attached to it. Moreover, the proximity effect under the size quantization condition has been examined in the superconductor-semiconductor composite. Each of the stated effects by itself could causeT _c enhancement in general as more semiconductor blocks are added to the system. We extend our study in this paper to analyze the combined actions of phonon spectral change and proximity effect without size quantization condition onT _c variation in members of the Tl₁ series of high-T _c superconductors. Our results indicate that an optimumT _c is obtained if the stated effects are included in the idealized unit cells of the superconductors made up of a superconductor-semiconductor array.     

Anomalous Hall Effect in Sn1?x?yMnxEuyTe and Sn1?x?yMnxEryTe Mixed Crystals

The Anomalous Hall Effect (AHE) was investigated in IV–VI ferromagnetic semimagnetic semiconductors of Sn_1–x Mn _x Te codoped with either Eu or Er. The analysis of experimental data is as follows. Hall resistivity and magnetization showed that AHE coefficient R _s depends on temperature and its value decreases with thetemperature increase. We observe that above ferromagnet–paramagnet transition temperature R _s changes sign. We discuss the possible physical mechanisms responsible for observed temperature dependence of R _s , particularly change of the sign.     

Synthesis of a new perovskite Pb(Li14Nb34)O3

A high-pressure technique was adopted to obtain perovskite-type $\text{Pb(Li}{}_{\mathrm{<mtext>1</mtext><mtext>4</mtext>}}\text{Nb}{}_{\mathrm{<mtext>3</mtext><mtext>4</mtext>}}\text{)}\text{O}{}_3$. A new perovskite $\text{Pb(Li}{}_{\mathrm{<mtext>1</mtext><mtext>4</mtext>}}\text{Nb}{}_{\mathrm{<mtext>3</mtext><mtext>4</mtext>}}\text{)}\text{O}{}_3$ was characterized to have a cubic symmetry with $\text{a}{}_{\mathrm{<mtext>o</mtext>}}\text{= 4.069}\text{A}\text{?}$; Li and Nb ions in the B-site of perovskite lattice may be in a random arrangement.     

Bulk crystalline BaPb34Bi14O3: A ceramic superconductor

The preparation conditions of the high T_C ceramic superconductor Ba(Pb,Bi)O₃ is correlated with the superconducting transition. Transition onsets of all materials are similar, but transition widths and transition completeness is strongly dependent on firing temperature. Only materials prepared over a narrow temperature range, resulting in a nearly ideal weight loss, have a complete and narrow transition.     

Electrostriction in Pb (Zn13Nb23)O3

The electrostriction in $\text{Pb (Zn}{}_{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}\text{Nb}{}_{\mathrm{<mtext>2</mtext><mtext>3</mtext>}}\text{)}\text{O}{}_3$ crystals has been investigated using a strain gauge method. In the ferroelectric phase below 140 C, the strain vs the electric field shows a hysteresis, which is ascribed to the effect of ferroelectric domains. A quadratic relation holds between the strain x and the electric polarization P as x = QP² above about 170 C in the paraelectric phase. Values of the electrostrictive Q coefficients are determined from the measurements near 190 C, as Q₁₁ = 1.6·10^?2m⁴/C², Q₁₂ = ?0.86·10^?2m⁴/C², and Q₄₄ = 0.85·10^?2m⁴/C².     

Magnetic,electrical and thermal studies on the V1−xMox02

The monoclinic-to-tetragonal structure transition of oxides V_1?xMo_x0₂ with $\text{0≤}\text{x}\text{≤0.20}$ has been studied by means of DTA, X-ray diffraction, magnetic susceptibility (powder samples) and electrical conductivity (single crystals) measurements within the temperature region 80 K to 400 K. A linear decrease of the transition temperature of 11 K per atom % Mo was observed. The magnetic susceptibility of the low temperature phase was found to be temperature independent paramagnetic for all preparations. Electrical conductivity measurements on the same phase showed crystals with $\text{x}\text{? 0.04}$ to be semiconducting, while a metallic behavior was observed in the region $\text{0.10 ?}\text{x}\text{? 0.14}$.