PUMP-TUNING KTP OPTICAL PARAMETRIC OSCILLATOR WITH CONTINUOUS OUTPUT WAVELENGTH PUMPED BY A PULSED TUNABLE Ti:SAPPHIRE LASER

We report on the implementation of a KTP optical parametric oscillator pumped by a pulsed tunable Ti:sapphire laser. Two major improvements were achieved, including the connection of the signal and idler tuning ranges and the high-output conversion efficiency through the signal and idler tuning ranges. Both in the signal and idler, the continuous output wavelength from 1.261 to 2.532μm was obtained by varying the pump wavelength from 0.7 to 0.98μm. The maximum output pulse energy was 27.2mJ and the maximum conversion efficiency was 35.7% at 1.311μm (signal).     

Dynamical Hopf bifurcation in piezoelectric semiconductor resonators

Time-dependent Hopf bifurcations in the current-voltage characteristics of piezoelectric semiconductor resonators were investigated experimentally. The switching transition between acoustic bistable states was observed under a quasi-static variation of applied voltage. The peculiar pulse responses of the resonant currents were observed when the rise-time of the pulses exceeded the eigen-period of the system. The existence of a metastable state in the dynamical Hopf bifurcation are discussed.     

Criticality and phase transitions in ionic fluids

Recent experimental investigations of criticality and phase separation in ionic fluids have revealed behavior of great theoretical interest. In seeking to understand the experiments, some of which appear to exhibit argonlike criticality and some of which exhibit classical (mean-field) criticality, a convenient starting point is the restricted primitive model (RPM) of symmetrically charged hard spheres, all of equal diameter , each sphere bearing a positive or negative charge of magnitudeq. There is overall charge neutrality, so that the expected number densities of the anions and cations are equal, ₊= _-. Studies of RPM charge-charge and density-density correlation functions indicate that the fluctuation-suppressing mechanism that yields mean-field critical behavior in nonionic systems with long-range interparticle potentials is not operative in the RPM. On the basis of plausible assumptions, Ising-like behavior is instead expected. The above work is summarized. New work of Zhang and the author is outlined, showing that when one loses the RPM symmetry (through, e.g., different valence, diameter, or dipole moment of anions and cations) a strong coupling between charge-charge and density-density correlation ensues. The way in which this can be expected to give rise to mean-field or mean-field-like behavior is noted. Other new observations concern the mean-field analogy found by Høye and the author between the parameter 2/(d–2) (d is the dimensionality) in that model and the monomer number in high polymers, with respect to the coexistence-curve shape dependence on those parameters.     

过渡金属化合物的NMR

金属原子和配位体原子均可用作过渡金属化合物的NMR研究,它们的谱特征与常规的NMR谱不同,文中以¹H和⁹⁵Mo为例进行了讨论.     

几种叔丁墓酚化合物的核磁共振研究

研究了11种叔丁基酚化合物的化学位移和偶合常数,并讨论了影响因素.     

High mobility In2O3:H transparent conductive oxides prepared by atomic layer deposition and solid phase crystallization

The preparation of high‐quality In₂O₃:H, as transparent conductive oxide (TCO), is demonstrated at low temperatures. Amorphous In₂O₃:H films were deposited by atomic layer deposition at 100 °C, after which they underwent solid phase crystallization by a short anneal at 200 °C. TEM analysis has shown that this approach can yield films with a lateral grain size of a few hundred nm, resulting in electron mobility values as high as 138 cm²/V s at a device‐relevant carrier density of 1.8 × 10²⁰ cm^–3. Due to the extremely high electron mobility, the crystallized films simultaneously exhibit a very low resistivity (0.27 mΩ cm) and a negligible free carrier absorption. In conjunction with the low temperature processing, this renders these films ideal candidates for front TCO layers in for example silicon heterojunction solar cells and other sensitive optoelectronic applications. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

氢气流量对混合物理化学气相沉积法制备MgB_2超薄膜的影响

用混合物理化学气相沉积法(Hybrid physical-chemical vapor deposition简称为HPCVD)制备了MgB2超薄膜.在背景气体压强、B2H6的流量和成膜时间等条件一定的情况下,当氢气的流量从200到400sccm范围内变化时,观察了其对成膜的影响.结果显示,随氢气流量增大,膜表面粗糙度增大,同时膜面的连接性变好,伴随着样品的超导转变温度得到提高.对于平均厚度是10nm和15nm的样品,氢气流量分别是200sccm和300sccm时,Tc分别是26K和33K与28K和37K.     

多模虚共轭相干态与多模真空态组成的叠加态光场的等阶N次方H压缩

构造了由多模虚共轭相干态|{iZ_j^*}〉_q与多模真空态|{0_j}〉_q两者的线性叠加所组成的两态叠加多模叠加态光场|{Ψ_q⁽²⁾}〉_q.利用多模压缩态理论,首次对该态的等阶N次方H压缩特性进行了详细研究.结果发现:态|{Ψ_q⁽²⁾}〉_q是一种典型的多模非经典光场,它可呈现出周期性变化的、任意阶的等阶N次方H压缩效应.     

Heat Content Asymptotics for Oblique Boundary Conditions

We consider the short-time heat content asymptotics for oblique boundary conditions. The first few coefficients in the asymptotic expansion are calculated.     

非线性左手材料中的二次谐波

基于电磁场理论，推导了无耗非线性左手材料中二次谐波的曼利－诺关系，及相位匹配条件下正向基波与逆向二次谐波的能量转换过程及其空间分布.验证了可将无耗非线性左手材料的入射面作为反射镜，把能量以二次谐波的形式反射.同时分别给出有限厚度介质板中基波和二次谐波的场强分布数值结果，验证了结论的正确性.最后从相位失配角度说明了相位匹配是分析非线性左手材料二次谐波的重要条件.这为研究左手材料的非线性理论奠定了基础.