液体表面波振幅与激发深度的关系

研究了液体表面波振幅随激发深度的变化特性.采用探针式激发器激发,观察到液体表面波的衍射图样;改变激发深度,得到不同激发深度处的衍射图样;根据衍射图样分布与表面波振幅之间的关系并进行计算机编程,获得表面波振幅与激发深度之间的关系.用最小二乘法拟合,发现:液体表面波振幅随激发深度的增加而减小,并呈指数规律.     

液体表面波振幅与激发深度的关系

研究了液体表面波振幅随激发深度的变化特性.采用探针式激发器激发,观察到液体表面波的衍射图样|改变激发深度,得到不同激发深度处的衍射图样|根据衍射图样分布与表面波振幅之间的关系并进行计算机编程,获得表面波振幅与激发深度之间的关系.用最小二乘法拟合,发现|液体表面波振幅随激发深度的增加而减小,并呈指数规律.     

Superposed Transparency Effect and Entanglement Generation with Hybrid System of Photonic Molecule and Dipole Emitter

We theoretically investigate the transparency effect with a hybrid system composed of a photonic molecule and dipole emitter. It is shown that the transparency effect incorporates both the coupled resonator-induced transparency(CRIT) effect and the dipole-induced transparency(DIT) effect. It is found that the superposed transparency windows are consistently narrower than the CRIT and DIT transparency windows. Benefiting from the superposed transparency effect, the photonic Faraday rotation effect could be realized in the photonic molecule system, which is useful for entanglement generation and quantum information processing.     

氢键作用对基于异佛尔酮发光材料的荧光性能的影响

合成了3种基于异佛尔酮的新型单晶荧光材料:3-二丙烯腈基-5,5-二甲基-1-苯乙烯基环己烯(DCDSC)、3-二丙烯腈基-5,5-二甲基-1-(3-羟基苯乙烯基)环己烯(DCDH3C)及3-二丙烯腈基-5,5-二甲基-1-(4-羟基苯乙烯基)环己烯(DCDH4C)。通过氢核磁共振谱和元素分析确定了它们的分子结构。通过单晶X射线衍射获得了3种材料的晶体结构数据。DCDSC、DCDH_3C和DCDH_4C的紫外吸收光谱依序分布在长波区的390,398,424 nm,短波区分布在268,269,283 nm。DCDSC、DCDH3C和DCDH_4C在THF中的最大发射峰分别位于522,549,567 nm。与DCDSC相比,3位羟基取代的DCDH3C的发射波长红移了27 nm,而4位取代羟基的DCDH4C的发射波长红移了45 nm。其主要原因在于DCDSC、DCDH_3C和DCDH_4C存在不同的氢键作用,当然,取代基的类型及位置等也可能对材料的发射波长产生一定作用。     

Generation of Time-Bin Entangled Photon Pairs Using a Single Three-Level Emitter

The single-photon emission of a classically pumped three-level Λ-type emitter in a high-Q cavity is studied. In particular, generation of single-photon time-bin double-peak wave packets is shown.     

The Relationship of Cavitation to the Negative Acoustic Pressure Amplitude in Ultrasonic Therapy

The relationship between the cavitation and acoustic peak negative pressure in the high-intensity focused ultrasound(HIFU)Held is analyzed in water and tissue phantom.The peak negative pressure at the focus is determined by a hybrid approach combining the measurement with the simulation.The spheroidal beam equation is utilized to describe the nonlinear acoustic propagation.The waveform at the focus is measured by a fiber optic probe hydrophone in water.The relationship between the source pressure amplitude and the excitation voltage is determined by fitting the measured ratio of the second harmonic to the fundamental component at the focus,based on the model simulation.Then the focal negative pressure is calculated for arbitrary voltage excitation in water and tissue phantom.A portable B-mode ultrasound scanner is applied to monitor HIFU-induced cavitation in real time,and a passive cavitation detection(PCD)system is used to acquire the bubble scattering signals in the HIFU focal volume for the cavitation quantification.The results show that:(1)unstable cavitation starts to appear in degassed water when the peak negative pressure of HIFU signals reaches 13.5 MPa;and(2)the cavitation activity can be detected in tissue phantom by B-mode images and in the PCD system with HIFU peak negative pressures of 9.0 MPa and 7.8 MPa,respectively,which suggests that real-time B-mode images could be used to monitor the cavitation activity in two dimensions,while PCD systems are more sensitive to detect scattering and emission signals from cavitation bubbles.     

正切平方量子阱中三次谐波产生的研究

用量子力学中的密度矩阵算符理论推导出了正切平方量子阱中三次谐波产生的解析表达式,并以典型的GaAs正切平方量子阱为例进行数值计算.计算结果表明,该势阱中的三次谐波系数与势阱深度y0、势阱宽度b和弛豫常数(Π)Γ有关.通过调节V0、b和(Π)Γ可以获得比较大的三次谐波系数,从而为实验研究和实际生产提供必要的理论依据.     

A Study of Small Amplitude Ion Acoustic Double Layers in a Multi-Species Unmagnetized Plasma

We report here analytic solutions for weak ion acoustic double layers in an unmagnetized multi-species plasma having two electron components, each described by a Boltzmann distribution, and two ions of different masses, each described by usual fluid equations. The velocity and the width of the double layers for different amplitude has been studied.     

Extended Cylindrical Low-Pressure Arc Discharge Plasma Emitter for Generation of a Radially Diverging Electron Beam

Russian Physics Journal - The paper presents the results of studies of processes of generation of a beam-plasma formation in an extended cylindrical hollow mesh anode with a diameter of 115 mm and...     

声悬浮实验中谐振腔形状对声压大小的影响研究

研究了不同谐振腔接收器表面的声压大小,发现谐振腔内增减凹球面反射面对声压波形有较大影响.分析了声压波形发生变化的原因,认为增加凹球面反射面时,声压波形变化是由于声波在谐振腔上下两表面存在非垂直反射.     

Features of Normal Higher-Order Acoustic Wave Generation in Thin Piezoelectric Plates

Acoustical Physics - The article studies the spectrum of acoustic oscillations generated by interdigital transducers in a plate made from a LiNbO3 piezocrystal with a thickness on the order of the...     

Effect of Pumping Pulse Duration on Echo Signal Amplitude in Four-Pulse PELDOR

The impact of pumping pulse duration on four-pulse pulsed electron?Celectron double resonance (PELDOR) data was experimentally studied. For biradicals with known distances between two spin labels, it is shown that refocused echo amplitude decreases with increasing the pumping pulse duration and decreasing the distance between spin labels. The effect becomes substantial when the pumping pulse duration is comparable or exceeds the inverse value of the dipole?Cdipole interaction between spin labels. This effect is essential for determination of distance distribution between labels in double-labeled molecules and for determination of the number of labels in clusters of spin-labeled molecules. PELDOR signal distortion was observed when the pumping pulse position in the time scale coincided with those of the detecting pulses. An approach of signal correction to eliminate this distortion is proposed.     

Acoustic manipulation of active spherical carriers: Generation of negative radiation force

This paper examines theoretically a novel mechanism of generating negative (pulling) radiation force for acoustic manipulation of spherical carriers equipped with piezoelectric actuators in its inner surface. In this mechanism, the spherical particle is handled by common plane progressive monochromatic acoustic waves instead of zero-/higher- order Bessel beams or standing waves field. The handling strategy is based on applying a spatially uniform harmonic electrical voltage at the piezoelectric actuator with the same frequency of handling acoustic waves, in order to change the radiation force effect from repulsive (away from source) to attractive (toward source). This study may be considered as a start point for development of contact-free precise handling and entrapment technology of active carriers which are essential in many engineering and medicine applications.     

Phase Synchronization of Coupled Rossler Oscillators: Amplitude Effect

Phase synchronization of two linearly coupled Rossler oscillators with parameter misfits is explored.It is found that depending on parameter mismatches,the synchronization of phases exhibits different manners.The synchronization regime can be divided into three regimes.For small mismatches,the amplitude-insensitive regime gives the phase-dominant synchronization; When the parameter misfit increases,the amplitudes and phases of oscillators are correlated,and the amplitudes will dominate the synchronous dynamics for very large mismatches.The lag time among phases exhibits a power law when phase synchronization is achieved.     

Gas Phase Emitter Effect of Thulium within Ceramic Metal Halide Lamps in Dependence on Frequency

The gas phase emitter effect within ceramic metal halide (CMH) lamps reduces the effective work function of the electrode material and, therewith, the electrode temperature. An investigation of the gas phase emitter effect of thulium (Tm) within CMH lamps seeded with Tm iodide (TmI3) is carried out. For this purpose, phase resolved images of the arc attachment and measurements of the electrode temperature, Tm atom and ion densities are performed in dependence on operating frequency by pyrometry and optical emission spectroscopy. Additionally, the influence of a sodium iodide (NaI) admixture is studied. The emitter effect is generated by means of a monolayer of Tm atoms on the electrode surface generated by a Tm ion current within the cathodic phase. It overlaps onto the anodic phase at higher frequencies of some hundreds of hertz. The reason is the finite life time of the monolayer, which is determined by the adsorption energy of Tm on the tungsten surface. Due to the low electric field strength in front of the anode and the mass inertia, the emitter ions and atoms remain in front of the anode. They retard the decay of the monolayer and with it the increase of the work function. Moreover, a comparison of a lamp seeded with TmI3 and sodium iodide (NaI) with a lamp seeded only with TmI3 illustrates a slight reduction of the electrode tip temperature caused by a higher Tm saturation vapour pressure and a higher Tm amount within the lamp filling. The influence of Na appears to be quite low. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Effect of Physical Parameters on Shape Instability of Sonoluminescing Bubbles

Considering the vapour effects, we calculate the shape instability of single-bubble sonoluminescence （SBSL） in the phase diagram of the amplitude of driving pressure versus ambient radius, i.e. the pa - R0 diagram. The numerical calculation shows that the results calculated by the present model are reliable, even some parameters, such as the binary diffusion constant and the thermal conductivity of the mixture of argon and water vapour inside the bubble, are roughly evaluated. It is found by numerical calculation that the shape stable area of a single argon bubble in those viscous liquids with low vapour pressure, such as oil of vitriol, glycerol and 1,2- propanediol, can be extended to a wider region. Combining with the calculation of the maximum temperature inside the bubble, we may predict that these areas are probably the stable region of SBSL.