Nonlinear Theory of Spectra of Thermally Stimulated Currents in Complex Crystals with Hydrogen Bonds

The nonlinear theory of thermally stimulated depolarization currents is developed. The theory explains the processes of hetero- and homocharge relaxation in complex crystals with hydrogen bonds and allows the relaxation oscillator parameters to be calculated using the quadratic approximation for the external electric field.     

Maxwellian Relaxation in Crystals with Hydrogen Bonds

Russian Physics Journal -     

Correlated Tunneling in Hydrogen Bonds

We study the quantum nature of the protons participating in hydrogen bonds in several ice structures by analyzing the one particle density matrix. We find that in all cases, including ice Ih, the most common form of ice, and the high pressure phases, ice VIII, VII, and X, the system is ground-state dominated. However, while the dynamics is uncorrelated in the structures with standard asymmetric hydrogen bonds, such as ice Ih and VIII, local correlations among the protons characterize ice VII and, to a lesser extent, ice X in the so-called low barrier hydrogen bond regime. The correlations appear along the path to hydrogen bond symmetrization, when quantum fluctuations delocalize the proton on the two bond sides. The correlations derive from a strong requirement for local charge neutrality that favors concerted motion along the bonds. The resulting behavior deviates substantially from mean field theory, which would predict in ice VII coherent tunneling of the proton between the two bond sides, thereby causing an ionization catastrophe. Due to the correlations, the quantum state of the proton is entangled.     

Nonlinear Electrophysical Phenomena in Ionic Dielectrics with a Complicated Crystal Structure

Russian Physics Journal - The methods of quasi-classical kinetic theory are used to study the phenomena of nonlinear relaxation polarization in ionic dielectrics with a complicated crystal lattice...     

Quantum Symmetrization of Hydrogen Bonds in Ice

JETP Letters - The structure of hydrogen bonds in ice is considered theoretically taking into account the quantum tunneling of protons along the bonds and the Coulomb interaction of protons of...     

波片对偏振激光干涉仪非线性误差的影响

利用琼斯矩阵理论,研究了基于偏振移相技术的激光干涉仪中1/4波片和1/2波片的非理想因素导致非线性误差的产生机理和变化规律.理论研究表明:在导致波片处于非理想状态的各个因素中,干涉仪中两个1/4波片的差模延迟角误差Δεq所产生的恒定偏置误差和接收装置中1/4波片的延迟角误差εq3所引起的一次谐波非线性误差,是组成干涉仪非线性误差的最主要的两个部分;波片各种误差源非理想因素导致的非线性误差在小误差情况下经线性叠加后由干涉仪最终输出.     

Computer Analysis of Thermally Stimulated Currents in Electrets with Hydrogen Bonds

Russian Physics Journal -     

An Optical Model for Polarization Microscopy Analysis of Pulp Fibre-to-Fibre Bonds

Pulp fibre-to-fibre bonds were studied using polarization microscopy and microtome cuts. The experiments showed considerable discrepancies between these two experimental methods. While microtome cuts clearly show if a bond between two fibres has formed, polarization microscopy cannot unambiguously discern between crossed unbonded fibres and bonded fibres; also certain bonds cannot be detected with this method. To examine these shortcomings, a physical model of polarization microscopy of bonded and unbonded pulp fibers was built. Experimental validation of the model gave good agreement between calculations and reflectance measurements. Calculations based on this model clearly demonstrate that only bonded fibres resembling a plane parallel plate show as bonds. However, crossings of unbonded fibers also appear as bonds if the two fibres are flat and plane parallel to each other. The model provides a consistent interpretation for polarization microscopy imaging of pulp fibre bonds, an important topic in research of mechanical and optical properties of fibrous composites like paper.     

基于SOA偏振旋转光开关的性能研究

利用SOA中的偏振主态的概念,理论分析了SOA中的偏振旋转的问题,并以此为基础提出了一种基于SOA中偏振旋转的光开关。这种光开关以SOA和偏振分柬器（Polarization Beam Combiner,PBC）为核心元件,利用光在SOA中的偏振旋转实现了光信号的开关,这种光开关具有开关速度快,功率均衡,易集成等优点,实验得到的开关消光比达到24dB以上,开关速度达到20ns。     

Spectral Energy Characteristics of the Hydrogen Bonds of 1,1-Diphenylethanol

We have measured the parameters of the bands of the stretching vibrations _OH (frequency width, peak and integral intensities) in the IR spectra of a large number of H-complexes of 1,1-diphenylethanol [(C₆H₅)₂C(CH₃)OH] with solvents of different protophilic forces, for which systematic data are not available. The enthalpies of formation of the H-complexes and the protogenic properties of the alcohol indicated were estimated, and also correlations between spectral characteristics were established.     

阶梯式循环冲击下煤中氢键红外光谱变化规律

煤结构中存在的大量氢键对其化学结构和性质具有重要影响。为了研究煤在冲击破坏过程中氢键的变化。设计落锤循环冲击系统,实现对煤样的循环定量冲击。利用红外光谱仪进行光谱分析。研究得出东庞1/3焦煤主要的氢键类型是free OH groups, OH…π, OH…OH, cyclic OH tetramers和OH…N以及它们随冲击破坏的变化规律。在冲击力的作用下,煤体分子间氢键吸收强度变化非常明显,自由羟基也在冲击作用下发生机械力化学反应。对红外光谱进行高斯函数拟合分峰,发现各类氢键吸收强度随着冲能量的增加而减小,但其趋势在放缓。统计两者关系,得到各类氢键的光谱吸收强度与冲击能量的拟合方程,两者符合幂函数关系。对比拟合方程的幂指数,得出氢键在受冲击破坏时发生变化的敏感性顺序：free OH groups>cyclic OH tetramers>OH…N>OH…π>OH…OH。     

Nonlinear Polarization Rotation-Based Mode-Locked Erbium-Doped Fiber Laser with Three Switchable Operation States

A simple mode-locked erbium-doped fiber laser （EDFL） with three switchable operation states is proposed and demonstrated based on nonlinear polarization rotation. The EDFL generates a stable square pulse at a third harmonic pulse repetition rate of 87kHz as the 1480 nm pump power increases from the threshold of 17.5 m W to 34.3mW. The square pulse duration increases from 105 ns to 245ns as the pump power increases within this region. The pulse operation switches to the second operation state as the pump power is varied from 48.2mW to l16.Tm W. The laser operates at a fundamental repetition rate of 29 kHz with a fixed pulse width of 8.5 μs within the pump power region. At a pump power of ll6.TmW, the average output power is 3.84mW, which corresponds to the pulse energy of 131.5 ng. When the pump power continues to increase, the pulse train experiences unstable oscillation before it reaches the third stable operation state within a pump power region of 138.9 m W to 145.0 m W. Within this region, the EDFL produces a fixed pulse width of 2.8 μs and a harmonic pulse repetition rate of 58 kHz.     

基于非线性偏振旋转效应的多波长光纤激光器

多波长光纤激光器是未来波分复用光通信系统的理想光源,提出和展示了一个基于非线性偏振旋转效应的多波长光纤激光器,非线性偏振旋转诱导的强度相关非均匀损耗能有效地抑制均匀加宽增益介质掺铒光纤中的模式竞争,从而使光纤激光器在室温下产生稳定的多波长输出,实验实现了最多18个波长的多波长输出.另外,此激光器没有使用传统的滤波器,而是在激光腔内插入一段保偏光纤,保偏光纤与偏振相关隔离器构成一等效Lyot双折射光纤周期性滤波器.利用这种在线型的双折射光纤滤波器简化了光纤激光器的结构,使它更易于集成.还实验研究了多波长输出随抽运功率的演化,发现抽运功率对多波长的均匀性影响很大.     

A Mathematical Theory for Vibrational Levels Associated with Hydrogen Bonds I: The Symmetric Case

We propose an alternative to the usual time–independentBorn–Oppenheimer approximation that is specifically designed todescribe molecules with symmetrical Hydrogen bonds. In our approach,the masses of the Hydrogen nuclei are scaled differently from thoseof the heavier nuclei, and we employ a specialized form for theelectron energy level surface. Consequently, anharmonic effects playa role in the leading order calculations of vibrational levels. Although we develop a general theory, our analysis is motivated byan examination of symmetric bihalide ions, such as FHF ⁻ orClHCl ⁻. We describe our approach for the FHF ⁻ ion in detail. Partially Supported by National Science Foundation Grants DMS–0303586 andDMS–0600944.