基于可视化学传感阵列的农药快速检测新方法

采用可视化阵列传感技术,以卟啉及其衍生物和指示剂作为传感元件,构建了一种对农药敏感的可视化学传感阵列。该传感阵列可以在常温常压下对浓度为0.1 mg/L的12种农药快速识别和分类,反应时间仅为1.5 min。采用聚类分析(HCA)和主成分分析(PCA)等统计学分析方法对检测结果进行分析,不同种类农药样品在聚类分析和主成分分析中均可以被准确归类。     

New approach to nonlinear dynamics of fullerenes and fullerites

A new type of nonlinear (anharmonic) excitations—bushes of vibrational modes—in physical systems with point or space symmetry is discussed. All infrared-active and Raman-active bushes for C₆₀ fullerene are found by means of special group-theoretical methods.     

Measurement of the flux of ultrahigh energy cosmic rays from monocular observations by the High Resolution Fly's Eye experiment

We have measured the cosmic ray spectrum above 10(17.2) eV using the two air-fluorescence detectors of the High Resolution Fly's Eye observatory operating in monocular mode. We describe the detector, phototube, and atmospheric calibrations, as well as the analysis techniques for the two detectors. We fit the spectrum to a model consisting of galactic and extragalactic sources.     

New mechanism for the alpha to omega martensitic transformation in pure titanium

We propose a new direct mechanism for the pressure driven alpha-->omega martensitic transformation in pure titanium. A systematic algorithm enumerates all possible pathways whose energy barriers are evaluated. A new, homogeneous pathway emerges with a barrier at least 4 times lower than other pathways. The pathway is shown to be favorable in any nucleation model.     

Apparent molar volumes of urea in several solvents as functions of temperature and concentration

Apparent molar volumes of urea are measured over a temperature range in water, methanol, ethanol, formamide, DMF and DMSO. The limiting apparent molar volumes show a large variation in different solvents. In marked contrast to the situation in water, the temperature dependence of the limiting apparent molar volumes in the nonaqueous solvents is slight. The concentration dependence is discussed qualitatively in terms of solute association.Now Diane Beaumont.     

最小熵产生定理与光学被动腔

基于文献[5]中我们所获得的本征型光学双稳系统的熵产生表达式,本文证明该系统(光学被动腔)能够很好地满足最小熵产生定理。 关键词：     

On the dynamic radial expansion of helical springs due to longitudinal impact

An analytical and experimental programme was conducted to investigate the dynamic radial expansion of helical springs due to longitudinal impact.The basic equations of motion were normalized in such a way that terms of the same order could be retained in a systematic manner. A minimum complexity model was then developed by making suitable approximations in the resulting simplified equations of motion. Finally, an expression for the dynamic radial expansion was obtained, and it was shown to be the result of a two-wave interaction.Impact tests were made on a specially designed spring and the resulting motions recorded by using a high speed motion picture camera. The experimental results support the predictions of the theory.     

Semigroup actions on posets and preimage quasi-orders

Structures consisting of a semigroup of (partial) functions on a set X, a?poset of subsets of X, and a preimage operation linking the two, arise commonly throughout mathematics. The poset may be equipped with one or more set operations, up to Boolean algebra structure. Such structures are finitely axiomatized here in terms of order-preserving semigroup actions on posets. This generalises Schein??s axiomatization of semigroups of partial functions equipped with the first projection quasi-order.