A Mössbauer investigation of the amorphous Tin-Antimony oxide films

The Tin-Antimony oxide films SN_1-xSb_xO₂ (x=0.00-0.66) with thickness about 1100Å have been prepared on glass substrates by CVD and studied by using CEMS and XRD. The broad line widths of Mössbauer spectra and of X-ray diffraction patterns indicate a distribution of the hyperfine parameters due to the distortion of the rutile lattice. A distribution fitting program has been used to evaluate the distribution of quadrupole splitting QS and of isomer shift IS in the samples studied.     

Preparation, characterization and magnetic properties of disubstituted ternary heteropolyoxometalates [TBA]3H n [PW9MoM2-O38(H2O)2]· 3C3H6O(TBA = tetrabutylammonium, M = transition metal)

Summary The half Wells-Dawson structure complex Na₉PW₈-MoO₃₄·11H₂O has been prepared by reaction of Na₂WO₄·2H₂O, Na₂MoO₄·2H₂O and KH₂PO₄ in water. A series of transition metal substituted heteropolyoxometalate complexes with ternary Keggin structures of the general formula [TBA]₃H _n [PW₉MoM₂O₃₈ (H₂O)₂]·3C₃H₆O (TBA = tetrabutylammonium; n = 2, M = Fe³⁺; n = 4, M = Mn²⁺,Co²⁺,Cu²⁺or Zn²⁺), have been synthesized using Na₉PW₈MoO₃₄·11H₂O and the transition metal nitrate as the starting materials in aqueous solution. The compounds were characterized by elemental analyses and spectroscopy. X.p.s. data indicate that the binding energies of all the elements in the title compounds are lower than those in similar compounds. The magnetic susceptibilities of the compounds reveal antiferromagnetic properties.     

Dy-BPMPHD一CTMAB荧光 体系的研究及其分析应用

本文对伪-BPMPHD-CTMAB荧光体系进行了研究.研究发现，Dya+能与BPMPHD和CTMAB形成离子缔合物，并发射出伪3t的特征荧光峰.}3十、Y'+ , Lu’十离子能增强体系的荧光强度，产生共发光效应.本文对该共发光体系进行了详细研究，由此提出了快速、灵敏测定痕量稀土伪3t的新方法，其测定线性范围为1.0X1。一’-1. 3X 10-Smol/L,检出限为2. 0X 10-enrol/L     

Mucin: Aggregation and colloidal interactions of relevance to some biomedical problems

Summary Mucus is the viscoelastic secretion that lines, most epithelial surfaces forming a protective, lubricating barrier. The viscoelastic properties of mucus arise from mucin, a glycoprotein of molecular weight ranging from 2–10 million. In this paper we address two problems where the aggregation and interactions of mucin with colloidal particles is of physiological relevance. The first deals with gastric mucin and the question of the mechanisms that prevent the stomach from digesting itself. Using dynamic light scattering techniques we show that solutions of gastric mucin aggregate belowpH 4. Very large aggregates with 100-fold slower diffusion constants than the mucin monomer are observed atpH 2. Viscosity measurements indicate that mucin will eventually gel at lowpH, thus acting as a diffusional, barrier and protecting the stomach. The second problem is concerned with the role of mucin in the nucleation of cholesterol crystals which lead to gallstone formation. Using dynamic light scattering we have shown that mucin at relatively low concentrations (4 mg/ml) promotes the fusion of phospholipid + cholesterol vesicles. The time evolution of the fusion process was measured. No changes in the aggregation state of the gallbladder mucin were observed during the fusion process, suggesting that this phenomenon is related to physico-chemical interactions between the polymer (mucin) and the colloidal particle (vesicle). Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4–8, 1994.     

均衡功率的超宽带可调谐掺铒光纤激光器

报道了一种功率均衡的超宽带可调谐掺铒光纤激光器.该激光器采用窄线宽可调谐FP滤波器、掺铒光纤、波分复用器和耦合器构成光纤环形腔激光器，并通过部分反馈光功率自动控制，对输出激光功率进行均衡.实现了87 nm带宽（1525~1612 nm）范围内，输出激光功率波动小于0.2 dB的均衡结果.输出激光3 dB线宽为0.26 nm，边模抑制比大于55 dB.     

栅极和阴极的相对高度对电子传输比的影响

用边界元法(BEM)和Monte Carlo方法,对一种基于碳纳米管场发射大面积彩色平面型显示器的电子传输比进行了理论分析,通过模拟跟踪发射电子轨迹,证实改变阴极和栅极的相对高度,可以较大幅度地提高电子传输比阳极上电子的分布证实,我们设计的显示器结构能够满足高分辨率、高亮度的显示的要求,而且驱动电压低,工艺简单。     

螺旋波纹波导研究

从耦合波方程出发，利用阻抗微扰法对螺旋波纹波导的边界不规则性进行处理，得到螺旋波纹波导的一般性耦合波传输方程，及耦合系数表达式.根据螺旋波纹波导内模式耦合的规则,得出色散方程并分析其色散特性. 关键词： 螺旋波纹波导 耦合波方程 阻抗微扰 色散特性 本征模     

一类具多重特征的无解算子

本文给出一类型如P(x,D)=D₁⁴+x₁⁴D₂⁴-(i^1/2+(-i)^1/2)D₁²D₂+4x₁D₁D₂²-i(i^1/2-(-i)^1/2)x₁²D₂³+(1+2i)D₂²+C 或更一般地p(x,D)=L^tL(x,D)+C(L为无解算子)的多重特征算子。指出包括零阶项在内的低阶项对局部可解性能具有决定性影响。具体地说,在原点邻域上面所给算子p(x,D)的主部D₁⁴+x₁⁴D₂⁴为可解算子,当C=0时P(x,D)为不可解算子。但当C>0时又变为局部可解算子。类似地讨论了算子附加零阶项的一些情况。文章最后证明了当自由项f具形|x₁|ψ＇(x₂)(ψ为实函数)时,在原点邻域有古典解的充要条件为ψ(x₂)解析。     

镧系元素钨硅杂多配合物异构体的合成与表征

关于[Ln(XM_(11)O_(39))_2]~(n-)类配合物合成有一些报道,但它们均未指出其中配体及所得配合物的构型,本文以α-和β_2-SiW_(11)O_(39)~(8-)为配体,首次合成了双-(11-钨硅酸根)合镧系元素钾盐的异构体并进行了结构表征。 1 实验部分 1.1 仪器和试剂 pHS-2型酸度计;883型笔录式极谱仪,384B型极谱分析仪,阿尔法     

空间非傍轴激光束在非线性克尔介质中的相互作用

对于非线性克尔介质中的非傍轴双脉冲激光束的传输,通过数值求解修正的非线性Schroödinger方程发现:当入射光强度在一定的能量阈值以上,入射光束的间隔达到一定值时,空间双脉冲激光束在传输过程中会发生相互作用.这种相互作用不同于一般傍轴激光束之间的相互作用,它的作用效果以一束很小的分束光的形式表现出来.文中对这种相互作用的效果进行了报道,并对此做出了理论的解释.