LiNbO3:Ru晶体的光折变特性研究

采用丘克拉斯基法生长了单掺杂的LiNbO3∶Ru晶体,并对其作氧化处理。实验研究了LiNbO3∶Ru晶体二波混频条件下光栅记录特性和波长的依赖关系;并且研究了氧化处理对其透射谱和光栅记录特性的影响。研究结果表明,LiNbO3∶Ru晶体的最佳记录波长为458 nm;氧化处理会增加LiNbO3∶Ru晶体对光的吸收,同时提高光栅记录的灵敏度和饱和衍射效率,表现了不同于LiNbO3∶Fe晶体的氧化态依赖特性。分析认为,LiNbO3∶Ru晶体的反常氧化态依赖特性可能是由于出现了电子通道效应的暗衰减机制,以及Ru存在多个价态所造成的。     

空变菲涅耳联合变换相关器

提出了菲涅耳联合变换相关器(Fresnel Joint Transform Correlator,FnJTC)结构,给出了数学推导过程,并通过计算机模拟验证了可行性及其与传统相关器所不同的相关特性。在相关过程第一阶段中,菲涅耳联合变换相关器对输入的联合图像作菲涅耳变换,代替了传统联合变换相关器(JTC)的傅里叶变换。与传统相关器相比,菲涅耳联合变换相关器是空变系统,相关峰值依赖于输入参考图像与目标图像的相似性、两图像之间的相对位置及参考图像(或目标图像)的线性相位调制。     

Application of reciprocal theorem for calculating the transverse displacement equations of the thin elastic circular plates

On the basis of [1] and [2], this paper further extends the Reciprocal Theorem to the thin elastic circular plates and proposes a general convenient new method, which can easily solve the transverse displacement equations of the circular plates with various complex edges and loads.     

室内装修材料中的有害物质

本文对室内装修材料中的有害物质———甲醛、苯、氨气、放射性物质氡,从它们的来源、性质、对人体的危害作用、中毒机理等方面做了论述,提出了在室内装修中创造“绿色环境”的具体措施。     

铂、钯负载型活性催化剂的制备及其对一氧化碳的催化氧化活性

用浸渍法分别将铂、钯负载在铝柱撑蒙脱石载体上,制备了铂、钯负载铝柱撑蒙脱石催化剂。运用X射线衍射(XRD)、原子吸收光谱(AAS)、透射电镜(TEM)等分析方法对样品的性能和结构进行了表征,并考察了不同铂、钯负载量的催化剂对一氧化碳的催化氧化性能。结果表明,铂、钯均以高度分散的纳米粒子状态均匀分布在载体表面,并表现出良好的CO催化氧化活性。铂、钯在铝柱撑蒙脱石载体表面的有效负载率在70%~76%之间,在相同的设计负载量条件下,铂的实际负载量和有效负载率均略大于钯。CO催化氧化试验结果表明,相对于负载前,负载后催化剂的催化活性明显增加,且其催化活性随着铂、钯负载量的增加而不断增强。在相同温度和负载量条件下,钯负载型催化剂的催化活性明显高于铂负载型催化剂。     

SBA-15 Modified Carbon Paste Electrode for Rapid cTnI Detection with Enhanced Sensitivity

Cardiac troponin I (cTnI) is a cardiac muscle protein and forms a protein complextogether with troponin T and troponin C in heart. The troponin complex is broken upfollowing myocardial damage, and the individual protein components are released intothe blo…     

Effect of filament biasing on nanocrystalline-Si films deposited by hot wire chemical vapor deposition

Nanocrystalline silicon (nc-Si) films were deposited by hot wire chemical vapor deposition with applying positive or negative filament biases. These films were characterized by Raman spectroscopy, field emission scanning electron microscopy and X-ray photoelectron spectroscopy. Plasmon loss of the Si(2p) band region was shifted to higher energy due to dielectric changes with applied filament biases from negative to positive voltage. A semi-quantitative study of the valence band structure was employed to analyze the bias effect of the valance band in nc-Si networks. Nc-Si with a positive filament bias shows better microstructural properties than those with a negative bias and without biasing nc-Si films.     

Power factors of late rare earth-doped Ca3Co2O6 oxides

Polycrystalline samples of (Ca_1−xR_x)₃Co₂O₆ with R = Gd, Tb, Dy and Ho at x=0-0.1 were synthesized and the effects of rare earth substitution on their thermoelectric properties were investigated. In the high-temperature region, the rare earth substitution resulted in an increase in the Seebeck coefficients (S), and the S values increased with decreasing ionic radius of rare earth elements in the order Gd³⁺>Tb³⁺>Dy³⁺>Ho³⁺. In contrast, the influence of rare earth substitution on the electrical resistivity was small. The high-temperature power factor was thereby improved by the late rare earth substitutions, particularly those with Ho³⁺ for Ca²⁺. For the Ho-doped samples (x≤0.05), the power factor was significantly improved by increasing Ho concentration.     

An analysis on synthesizing large scales of one-dimensional silicon nano-structures by simple evaporation of sulfur-contained powders

The growth mechanism for synthesizing large scales of one-dimensional silicon nano-structures (silicon nano-wires (SiNWs) or silicon oxide nano-wires (SiO₂-NWs)) by a simple evaporation of sulfur-contained powders on silicon wafer is discussed. A novel sulfide-assisted mechanism referring to oxygen-assisted mechanism is proposed. Amongst this simple method, sulfide or pure sulfur can both assist the formation of SiNWs. The growth is fast and some SiNWs are easily oxidized to be amorphous structure of SiO₂-NWs under the low-vacuum system. The simple method suggests a useful route to achieve plenty of one-dimensional silicon nano-structures for further research.     

Deconjugative conversion of alpha-alkynyl esters to alpha,alpha-disubstituted beta-alkynyl esters

We report the development of a method for the conversion of a variety of conjugated alpha-alkynyl esters to alpha,alpha-disubstituted beta-alkynylesters through the use of strong amide bases. Studies indicate that the second equivalent of base leads to the dianion intermediate. Optimal conditions included the use of 2 equiv of lithium diisopropylamide in THF with HMPA as the cosolvent followed by trapping with a variety of carbon electrophiles. Trapping with bis-electrophiles leads to spiro cycloalkane products.