IR Spectroscopic Evidence of Hydrogen Bonding in Piperidine

Abstract

The IR spectra of piperidine dissolved in n-heptane revealed that a self-association equilibrium via weak hydrogen bonds exists in this system. The dimerisation constant was found to be 0.35 1·mol^?1 at 29°. No higher associates than dimers were found.     

Orthogonal polynomial approach to discrete Lax pairs for initial boundary-value problems of the QD algorithm

Using orthogonal polynomial theory, we construct the Lax pair for the quotient-difference algorithm in the natural Rutishauser variables. We start by considering the family of orthogonal polynomials corresponding to a given linear form. Shifts on the linear form give rise to adjacent families. A compatible set of linear problems is made up from two relations connecting adjacent and original polynomials. Lax pairs for several initial boundary-value problems are derived and we recover the discrete-time Toda chain equations of Hirota and of Suris. This approach allows us to derive a Bäcklund transform that relates these two different discrete-time Toda systems. We also show that they yield the same bilinear equation up to a gauge transformation. The singularity confinement property is discussed as well.     

Entropy Optimization,Maxwell–Boltzmann,and Rayleigh Distributions

In physics, communication theory, engineering, statistics, and other areas, one of the methods of deriving distributions is the optimization of an appropriate measure of entropy under relevant constraints. In this paper, it is shown that by optimizing a measure of entropy introduced by the second author, one can derive densities of univariate, multivariate, and matrix-variate distributions in the real, as well as complex, domain. Several such scalar, multivariate, and matrix-variate distributions are derived. These include multivariate and matrix-variate Maxwell–Boltzmann and Rayleigh densities in the real and complex domains, multivariate Student-t, Cauchy, matrix-variate type-1 beta, type-2 beta, and gamma densities and their generalizations.     

基于STM32F4的电机控制系统设计

为改善步进电机堵转、失步、超步等问题,提高步进精度,使步进电机能够快速准确定位,提出基于STM32F4微控制器的步进电机控制系统设计。通过改变PWM输出定时器的预分频值控制电机转速,直线阶梯形升降速算法实现调速;采用DMA方式控制电机脉冲数量,实现位置精确控制。实验以及实际应用情况表明,阶梯形升降速算法以及DMA方式位置控制算法能够满足一般要求,系统误差为±0.01度。系统精确度高、性能可靠、扩展性强,具有较高的应用价值。     

用SCLC法研究低k多孔SiO2:F薄膜的隙态密度

用溶胶-凝胶法制备了低k多孔SiO₂:F薄膜，用空间电荷限制电流法(SCLC)研究了多孔SiO₂:F薄膜中的隙态密度以及掺F量对隙态密度的影响，得到了平衡费米能级附近的隙态密度约为7×10¹⁵cm^-3·eV^-1，以及带隙中隙态随能量的分布. 并对造成隙态的主要原因也进行了讨论.     

Quantum uncertainty relations of Tsallis relative α entropy coherence based on MUBs

In this paper,we discuss quantum uncertainty relations of Tsallis relative α entropy coherence for a single qubit system based on three mutually unbiased bases.For α∈[1/2,1)U(1,2],the upper and lower bounds of sums of coherence are obtained.However,the above results cannot be verified directly for any α∈(0,1/2).Hence,we only consider the special case of α=1/n+1,where n is a positive integer,and we obtain the upper and lower bounds.By comparing the upper and lower bounds,we find that the upper bound is equal to the lower bound for the special α=1/2,and the differences between the upper and the lower bounds will increase as α increases.Furthermore,we discuss the tendency of the sum of coherence,and find that it has the same tendency with respect to the different θ or φ,which is opposite to the uncertainty relations based on the Rényi entropy and Tsallis entropy.     

Dynamics of coherence-induced state ordering under Markovian channels

We study the dynamics of coherence-induced state ordering under incoherent channels, particularly four specific Markovian channels: amplitude damping channel, phase damping channel, depolarizing channel and bit flit channel for single-qubit states. We show that the amplitude damping channel, phase damping channel, and depolarizing channel do not change the coherence-induced state ordering by l₁ norm of coherence, relative entropy of coherence, geometric measure of coherence, and Tsallis relative α-entropies, while the bit flit channel does change for some special cases.     

The Uniqueness of the World

We follow some wild speculations in trying to understand the uniqueness of our physical world, from the field concept to F-TheoryDedicated to Emilio Santos on his 70th birthday. I have enjoyed discussions with Emilio on physics for the last 40 years; in spite of disagreements on many issues, I have an everlasting admiration for him and for his approach to science     

氮分子激光照射增大了LiF:F_3~+心浓度

在液氮温度下采用氮分子激光(337nm)照射已着色的LiF晶体,能有效地产生高浓度的F_3~+心.文中详细地描述了着色LiF晶体中F_3~+心的产生方法、光谱特性及其形成机理.     

Temperature dependence of the ultraweak spontaneous photon emission from soya seeds

Summary The ultraweak radiation emitted from soya seeds during germination has been measured for different values of the temperature (20–35°C). The parameters relative to the photon emission time-counting series have been compared with the ones relative to germination and imbibition; it has been found that the activation energy relative to the process of the photon emission from live seeds is equal to that of the germination process (51 KJ/mole), demonstrating that the two processes are correlated. A function of the experimental parameters which eliminates the explicit dependence of the above biological processes on temperature has been proposed. The authors of this paper have agreed to not receive the proofs for correction.     

用2D NMR研究前胡香豆素F的结构

应用¹H-¹H COSY,¹³C-¹H COSY及COLOC并结合其它波谱技术对从中药白花前胡(Peucedanum praeruptorum Dunn)根中分得的一种新化合物前胡香豆素F进行了深入研究,其化学结构确定为3'-异戍烯酰氧基花椒内酯,为吡喃环上3'位烯醇羟基的氧原子和异戍烯酰基形成的烯醇酯.这种新颖结构在自然界中比较少见。     

Franck–Condon Factors and r‐Centroids for the B–, C–, F–, and G–X Band Systems of YF Molecule

The Franck–Condon factors and r‐centroids, which are very closely related to relative transition probabilities, have been evaluated by a more reliable numerical integration procedure for the B¹π–X¹Σ⁺, C¹Σ⁺–X¹Σ⁺, F¹Σ⁺–X¹Σ⁺, and G¹π–X¹Σ⁺ band systems of the YF molecule, using suitable potentials.