高凝固点原油与一般原油300℃以前组分的碳数分布特性比较

用气相色谱和色－质联用以对高凝固点（约42℃）原油及一般原油300℃以前组分的碳数分布情况作了分析和比较，并使用氧化铝多孔层空心毛细管柱分离了原油中石油气的低碳数组分，效果良好。     

A High-Precision Carbon-13 Shift Thermometer for the Temperature Range 100–300 K

The first carbon-13 shift thermometer for the temperature range of 100–300 K is based on the very rapid equilibration of a pair of semibullvalene valence tautomers. The temperature dependence of the equilibrium constant is reflected in strongly temperature-dependent shift differences Δδ between averaged signals, e.g.,d(Δδ)/dT= 0.051 ppm K⁻¹at 300, 0.087 ppm K⁻¹at 200, and 0.175 ppm K⁻¹at 110 K for the quaternary carbon atoms C2 and C6. At 37 temperaturesT, which were measured with calibrated platinum resistance thermometers, shift differences Δδ were taken from nondecoupled carbon-13 spectra recorded from solutions of 1 in mixtures of chlorodifluoromethane and deuterated dimethyl ether without spinning. The least-squares fit of these Δδ vsTdata to a polynomial equation of the fourth degree (Eq. [5],r²= 0.9999) allows the calculation of temperatures from measured shift differences with a standard deviation of 0.46 K and an estimated error of about 1 K. The heating effects of WALTZ-16 decoupling and the influence of solvents on Δδ are investigated. A comparison with existing NMR thermometers demonstrates the superior performance of the new carbon-13 shift thermometer with respect to precision and the accessible temperature range.     

Smooth local sinusoidal bases on two-dimensional L-shaped regions

In this article, we construct two-dimensional continuous/smooth local sinusoidal bases (also called Malvar wavelets) defined onL-shaped regions. With this construction, one is able to construct local sinusoidal bases and lapped orthogonal transforms (LOT) on arbitrarily shaped regions. This work is motivated from and useful in object-based video coding, where a segmented moving object may have arbitrary shape and block transform coding of this object is needed. Acknowledgements and Notes. His work was partially supported by an initiative grant from the Department of Electrical and Computer Engineering, University of Delaware, the Air Force Office of Scientific Research (AFOSR) under Grant No. F49620-97-1-0253, and the National Science Foundation CAREER Program under Grant MIP-9703377.     

Lie groups whose coadjoint orbits are of dimension smaller or equal to two

We give a complete classification of the class of connected, simply connected Lie groups whose coadjoint orbits are of dimension smaller or equal to two.     

Quantum orbits of theR-matrix type

Given a simple Lie algebra g, we consider the orbits in g^* which are of theR-matrix type, i.e., which possess a Poisson pencil generated by the Kirillov-Kostant-Souriau bracket and the so-calledR-matrix bracket. We call an algebra quantizing the latter bracket a quantum orbit of theR-matrix type. We describe some orbits of this type explicitly and we construct a quantization of the whole Poisson pencil on these orbits in a similar way. The notions ofq-deformed Lie brackets, braided coadjoint vector fields, and tangent vector fields are discussed as well.     

The special class generated by a PI-ring

In this note we show that the special class generated by a prime PI-ring is, up to isomorphism, a left and right equivalence class of orders in some matrix quotient ring. This research was supported by Hungarian National Foundation for Scientific Research grant No. T 16432 and by the Natural Science Foundation of Inner Mongolia Education Department.