掺杂和未掺杂氧化锌薄膜的拉曼光谱

利用拉曼光谱分别对不同衬底上,未掺杂和掺杂以及掺杂浓度不同的ZnO薄膜进行了系统的分析研究。其中ZnO薄膜均由溶胶-凝胶法制得,掺杂源为LiCl。测得的拉曼光谱显示,Pt/Ti/SiO2/Si衬底上生长的ZnO薄膜的拉曼特征峰(437cm-1)的强度明显高于SiO2/Si衬底上ZnO薄膜的拉曼特征峰的强度,说明Pt/Ti/SiO2/Si衬底上ZnO的晶化程度比SiO2/Si上ZnO的晶化程度高;但ZnO拉曼特征峰的位置和半高宽并没有发生变化,说明两种衬底上ZnO薄膜中应力大小没有发生变化。掺Li+后,580cm-1处的峰位向高频方向移动,且掺杂浓度越大频移量越大,说明掺杂已经在不同程度上引起了ZnO晶体中自由载流子浓度的变化。此外,还分析了掺Li+未在很大程度上引起ZnO晶格畸变的原因。     

The cosmic background radiation temperature at 1.3 mm

Summary The cosmic background radiation temperature at 1.3 mm wavelength has been determined by studying the absorption lines of the interstellar CN toward the star HD 154 368. The resulting value of (2.832±0.072) K is consistent with the weighted average,T _CBR=(2.78±0.01) K of the results obtained at λ≥1.0 mm. To speed up publication, the proofs were not sent to the authors and were supervised by the Scientific Committee.     

A short catalytic enantioselective synthesis of the vascular antiinflammatory eicosanoid (11R,12S)-oxidoarachidonic acid

[reaction: see text] An effective pathway is described for the synthesis of (11R, 12S)-oxidoarachidonic acid (1) from the achiral precursors shown.     

Particle collision rate in turbulent flow

The fluctuating relative motion of two solid particles or liquid drops in a turbulent gas flow is analysed, yielding an expression for collision rate as a function of the particle concentration and relaxation times and the turbulence intensity and scale. Unlike earlier theories, particles of intermediate size are included, having approach velocities neither well-correlated nor completely independent.     

The millimeter wave spectrum of phosphorus oxychloride

Millimeter wave rotational spectra of phosphorus oxychloride (OPCl₃) in the ground and excited vibrational states have been recorded and analyzed. The v₅ = 1 and v₆ = 1 state spectra show large splittings due to l resonance and the effect of the 2, -1 term r_t. Coriolis constants have been obtained for the two lowest degenerate states. The spectra of the asymmetric top species OP³⁵Cl₂³⁷Cl have been analyzed and centrifugal distortion constants obtained. These have been used to determine the harmonic force field of the molecule.     

Axially symmetric plumes at large Prandtl numbers

Summary The natural convection from a point source of heat is developed in an asymptotic series for moderate to large values of the Prandtl number.

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Zusammenfassung Die natürliche Konvektion von einer punktförmigen Wärmequelle wird in einer asymptotrischen Reihe für grosse und mässige Werte der Prandtl'schen Zahl dargestellet.

     

2,2-亚戊基-1,3-二氧六环-4,6-二酮与原甲酸三乙酯和芳香胺的反应

剂,在有机合成中已有一定应用。开展Meldrum's 酸系列化合物的研究,旨在:1.寻找有结构特点的新试剂,2.合成一系列新化合物,3.研究新化合物的应用。本文通过控制反应温度(28～29℃)催化剂用量(比文献用量多近一倍),提高了2,2-亚戊基-1,3-二氧六环-4,6-二酮(PDDO,3)的制备得率(由15%     

Parity violation observed in the beta decay of magnetically trapped 82Rb atoms

Laser cooling and atomic trapping techniques have been employed to confine polarized 82Rb atoms ( T1/2 = 75 s) in a magnetic time-orbiting-potential (TOP) trap. We have observed the parity-violating correlation between the emitted positron momentum and the parent nuclear spin as a continuous function of angle and positron energy for this pure Gamow-Teller (GT) transition. These proof-of-principle measurements demonstrate the utility of exploring fundamental symmetries in a TOP trap and the steps required to improve sensitivity in the search for physics beyond the standard model.     

甘氨酸衍生化β-环糊精键合硅胶液相色谱固定相的合成与评价

 β-环糊精键合硅胶经对甲苯磺酰化后,与甘氨酸反应得到甘氨酸衍生化β-环糊精键合硅胶固定相(GCDS)。考察了GCDS对位置异构体、丹磺酰化氨基酸异构体、苯丙酸类药物等的分离性能,研究了流动相中甲醇浓度、pH以及柱温对色谱保留行为的影响。