PdH、YH体系的结构与氢化反应的平衡压力

用相对论有效原子实势(RECP/SDD)和密度泛函(B3LYP)方法对PdH、YH体系的结构进行了优化,同时用Murrell-Sorbie函数导出PdH、YH分子的势能函数和光谱常数;得到PdH分子的基态为X2∑+,RPdH=0.154 1 nm,离解能De=2.511 eV,谐振频率ωe=2 019.458 9 cm-1;YH分子的基态为X1∑+,RYH=0.191 9 nm,离解能De=4.308 eV,谐振频率ωe=1 497.531 2 cm-1;并得到一键长为0.200 3nm,De=3.488 eV,ωe=1 309.318 2 cm-1的YH分子激发态.并根据以分子总能量中的振动能Ev代替固态能量,以电子和振动熵SEv代替固态熵的近似方法,计算了不同温度下Pd、Y与H2、D2、T2反应的一氢化物热力学函数△Hθ、△Gθ、△Sθ及氢化反应平衡压力,导出了与温度的依赖关系,结果表明:PdH(S)的生成焓为32.05kJ·md-1,与实验值37.30kJ·mol-1接近,YH(S)的生成焓为70.21 kJ·mol-1.     

LaCl分子结构与基态X1Σ+势能函数

用能量一致相对论有效核芯势和参阅文献基础上添加极化函数4f2g的价基组,在密度泛函理论(DFT)、多体微扰MPn和组态相关理论QCISD水平上计算了LaCl分子结构、离解能和振动频率.根据原子分子反应静力学原理,导出LaCl分子基态可能的电子状态和离解极限,用DFT中的B3LYP方法计算了基态X1Σ+势能曲线,拟合得到了MurrellSorbie解析势能函数及其在平衡位置附近的Dunham展开式,由此计算的振转常数与实验光谱数据完全符合.得到的解析势能函数可用于计算振转光谱精细跃迁结构和原子分子碰撞反应动力学过程 关键词： LaCl 相对论有效核芯势 解析势能函数 振转光谱常数     

氢同位素氚水T2 O((X)1A1)的解析势能函数

获得T2 O(X1A1)解析势能函数的主要困难在于Born-Oppenheimer近似下T2 O(X1A1)与H20(X1A1)势能函数的不可区分性.然而,在Bom-Oppenheimer近似下,分子势能函数实际上是键长、键角这些内坐标的函数,内坐标与核的运动相关,因而与分子振动频率、力常数和同位素质量有关.基于这种关系.用核运动效应对Born-Oppenheimer近似下T2 O(X1A,1)的电子能量进行修正,可获得体现同位素氢和氚质量差异的力常数,其结果与有关文献值是相符的.然后用多体项展式理论和方法,并考虑T2 O(X1A1)中两体项中的同位素效应,在确定T2 O(X1A1)离解极限和离解能以及计算所有两体项参数的基础上,获得了T2 O(X1A1)的解析势能函数.对应的等值势能图正确反映了T2 O(X1A1)的平衡结构特征,以及T OT→T2O和O2 T2→T2O的反应特点,为后续的碰撞研究提供了条件.     

7Li2(X1∑g+)分子的振动能级、转动惯量及离心畸变常数

使用密度泛函理论B3LYP和B3P86,以及组态相互作用方法CCSD(T)和QCISD,利用多个基组对7Li2(X1∑g )分子的平衡核间距(Re)、谐振频率(ωe)和离解能(De)进行了计算,发现在CCSD(T)/cc-PVQZ理论水平下得到的结果(Re=0.2698 nm,ωe;346.82 cm-1和De=1.0487 eV)与实验值非常相符.在0.15-2.7 nm的核间距内对7Li2(X1∑g )分子的势能曲线进行了计算,同时使用最小二乘法将计算结果拟合成了解析势能函数.利用拟合出的解析势能函数并结合Rydberg-Klein-Rees方法,计算了光谱常数ωeXe,αe和βe,其值分别为ωeXe=2.648 cm-1αe=0.00702 cm-1和Be=0.6601 cm-1,也与实验值非常相符.以得到的解析势能函数为基础,通过求解双原子分子核运动的径向Schrodinger方程,找到了J=0时7Li2(X1∑g )分子的全部41个振动态,求出了每一振动态的振动能级、振动经典转折点及其转动惯量,其值与实验结果相符得很好.同时,利用得到的解析势能函数,还首次求得了相应于各振动态的6个离心畸变常数(Dv,Hv,Lv,Mv,Nv和Ov).     

用耦合簇理论及相关一致五重基研究H2S(C2v,X1A′)的解析势函数

运用CCSD(T)理论和相关一致五重基对基态H2S分子进行了结构优化以及离解能和频率的计算.得到的结果是:该分子的基态为C2v结构,平衡核间距RS-H =0.13374 nm,键角∠HSH=92.3837°,离解能D0(H-SH)=3.8999 eV,频率υ1(a1)=1121.1865 cm-1,υ2(a1)=2727.5121 cm-1,υ3(a1)=2742.8342 cm-1.这些结果与实验结果均较为相符.对H2(X1Σ+g)分子使用cc-pV6Z、对SH(X2Π)自由基使用aug-cc-pV5Z基组进行几何优化和谐振频率的计算并进行单点能扫描,且将单点能扫描结果拟合成了解析的Murrell-Sorbie函数.与实验结果及其它理论结果的比较表明,本文关于SH(X2Π)自由基光谱常数(De,Re,ωe,Be,αe和ωeχe)的计算结果达到了较高的精度.采用多体项展式理论导出了H2S(C2v,X1A′)分子的解析势能函数,其等值势能图准确再现了该分子的离解能和平衡结构特征.报导了H2S(C2v,X1A′)分子对称伸缩振动等值势能图中存在的两个对称鞍点,对应于反应SH+H→SH2,势垒高度为0.1680×4.184 kJ/mol.     

OH分子基态(X~2Π)的结构与势能函数

采用密度泛函理论的B3LYP方法和二次组态相互作用(QCISD(T))方法优化计算了OH分子基态(X2Π)的平衡结构、振动频率和离解能.根据原子分子反应静力学原理,导出了OH分子基态(X2Π)的合理离解极限,采用最小二乘法拟合Murrell-Sorbie函数得到了相应的势能函数和与该基态相对应的光谱常数(Be,αe,ωe和ωeχe),计算结果与实验数据符合得相当好.     

OH分子基态(X2Ⅱ)的结构与势能函数

采用密度泛函理论的B3LYP方法和二次组态相互作用(QCISD(T))方法优化计算了OH分子基态(X2Ⅱ)的平衡结构、振动频率和离解能.根据原子分子反应静力学原理,导出了OH分子基态(X2Ⅱ)的合理离解极限,采用最小二乘法拟合Murrell-Sorbie函数得到了相应的势能函数和与该基态相对应的光谱常数(Be,αe,ωe和ωe xe),计算结果与实验数据符合得相当好.     

金属钯表面吸附氢同位素的量子力学计算

基于原子分子反应静力学和群论,应用密度泛函方法B3P86,对H(D,T)用基集合6311G,对Pd用基集合SDD,优化后进行势能面扫描,得到各分子的微观性质,包括构形、多重性、能量、电子状态、键角、平衡键长、谐振频率、谐性力常数和离解能,得到H2(D2,T2)和PdH(PdD,PdT)的电子状态分别为1Σ+g(D∞v)和2Σ+(C∞v),离解能分别为4.5918和2.6268eV.并进一步计算得到反应过程的△Hf°、△Sf°、△Gf°和平衡压力,并导出他们与温度的函数关系,计算结果与实验数据相近.     

用耦合簇理论及相关一致五重基研究H2S(C2v,X1A)的解析势函数

运用CCSD(T)理论和相关一致五重基对基态H2S分子进行了结构优化以及离解能和频率的计算. 得到的结果是: 该分子的基态为C2v结构, 平衡核间距RS-H = 0.13374 nm, 键角∠HSH = 92.3837°, 离解能D0(H-SH) = 3.8999 eV, 频率υ1(a1) = 1121.1865cm-1, υ2(a1) = 2727.5121 cm-1, υ3(a1) = 2742.8342 cm-1. 这些结果与实验结果均较为相符. 对H2(X1Σ+g)分子使用cc-pV6Z、对SH(X2Π)自由基使用aug-cc-pV5Z基组进行几何优化和谐振频率的计算并进行单点能扫描, 且将单点能扫描结果拟合成了解析的Murrell-Sorbie函数. 与实验结果及其它理论结果的比较表明, 本文关于SH(X2Π)自由基光谱常数(De, Re, ωe, Be, αe和ωeχe)的计算结果达到了较高的精度. 采用多体项展式理论导出了H2S(C2v, X1A')分子的解析势能函数, 其等值势能图准确再现了该分子的离解能和平衡结构特征. 报导了H2S(C2v, X1A')分子对称伸缩振动等值势能图中存在的两个对称鞍点, 对应于反应SH+H→SH2, 势垒高度为0.1680×4.184 kJ/mol.     

内层电子相关对NaH分子特征的影响

采用从头计算多参考组态CI方法(MRCI)研究了NaH分子的基电子态的内层电子相关对其分子特征的影响.计算了不同内层电子数目相关情况下的势能曲线,通过解析势能函数拟合,计算出了光谱常数.利用求解分子核运动薜定谔方程的方法,得出了振动能级.通过分析Na原子内层电子与价电子相互作用受H原子核影响的变化,对NaH分子的势能曲线、光谱常数和振动能级等特征量随相关电子数目的变化作了合理的解释.     

Self-organization of five species in a cyclic competition game

Cyclic competition game models, particularly the “rock–paper–scissors” model, play important roles in exploring the problem of multi-species coexistence in spatially ecological systems. We propose an extended “rock–paper–scissors” game to model cyclic interactions among five species, and find that two of the five can coexistent when biodiversity disappears, which is different from the “rock–paper–scissors” game. As the number of fingers is five, we named the new model the “fingers” game, where the thumb, forefinger, middle finger, ring finger, and little finger cyclically dominate their subsequent species and are dominated by their former species. We investigate the “fingers” model in two ways: direct simulations and nonlinear partial differential equations. An important finding is that the number of species in a cyclic competition game has an influence on the emergence of biodiversity. To be specific, the “rock–paper–scissors” model is in favor of maintaining biodiversity in comparison with the “fingers” model when the variables (population size, reproduction rate, selection rate, and migration rate) are the same. It is also shown that the mobility and reproduction rate can promote or jeopardize biodiversity.     

Experimental study on downstep in Chinese intonation

Downstep in pitch contour of Chinese Putonghua is examined using subtly designed sentences by controlling tone combinations. The results show both automatic and nonautomatic downstep phenomena exist in Chinese. In non-automatic downstep, low tones compress downwards the pitch range of the following syllables. and the main influence of downstep is on topline. Low tone not only lower the topline behind it, but also raise the high tones before it, the effects are compatible with each other. In automatic downstep, the topline of pitch contour in intonational phrase is presented as a linear downtrend, but it differs among speakers due to the effect of personal stress practice. In comparison with downstep phenomenon in other tone or non-tone languages, the downstep ratio in Chinese is not constant, and the domain of downstep is not limited within the adjacent tones.     

Contrastive analysis on tone between Putonghua and Taiwan Mandarin

The differences of the pitch and duration of Chinese syllables between Putonghua （PTH） and Taiwan Mandarin （TM） were studied. The speech materials to be used are not only isolated syllables, but also sentences. The results reveal that： For the isolated syllables, T1 and T2 in TM are influenced by Minnan dialect, therefore their pitch are lower than those in PTH. T3 is fall-rise in PTH, while it is fall in TM. Moreover, the syllable duration sequence for different tone is T3〉T2〉T1〉T4 in PTH, while it is T1〉T2〉T3〉T4 in TM. For the syllables in sentences, T2 is mid-rise in PTH, while it is mid-level in TM. And the T3 is longer than T4 but shorter than T1 or T2 in PTH, while it is the shortest in TM. Furthermore the effects of prosodic phrase boundary on duration for different tones are almost the same in PTH, but the lengthening part of T1 or T2 is longer than that of T3 or T4 in TM.     

Abelian-Higgs phase of SU(2) QCD and glueball energy

It is shown that SU(2) QCD admits an dual Abelian-Higgs phase, with a Higgs vacuum of a type-Ⅱ superconductor. This is done by using a connection decomposition for the gluon field and the random-direction approximation. Using a bag picture with soft wall, we presented a calculational procedure for the glueball energy based on the recent proof for wall-vortices [Nucl. Phys. B 741(2006)1].     

Signal generation in an isotropic medium in scanning electron acoustic microscope

Based on the research in Ref. [5][Materials Science and Engineering, 1989; A122： 57 63], an improved model of heat source is set up, the different modes of Lamb wave in an isotropic sample generated by a chopped electron beam at frequency f are obtained with integral transform and normal function expansion method, and the output signal of PZT coupled at the back surface of the sample is found out. The generation mechanism of SEAM （Scanning Electron Acoustic Microscopy） signal is discussed. It shows that the SEAM is a near field imaging technique with high spatial resolution and its best lateral spatial resolution is about 2√2α （α is the radius of the focused electron beam）. Some of experimental results of SEAM images are presented in the paper and it shows that the spatial resolution of SEAM is better than 0.5 μm and smaller than the thermal diffusion length of the sample. Therefore the character of near field imaging in SEAM is also proved experimentally.     

High efficiency filtering using two-dimensional photonic crystal coupled cavity structures

Transmission spectra of coupled cavity structures (CCSs) in two-dimensional (2D) photonic crystals (PCs) are investigated using a coupled mode theory, and an optical filter based on CCS is proposed. The performance of the filter is investigated using finite-difference time-domain (FDTD) method, and the results show that within a very short coupling distance of about 3λ, where λ is the wavelength of signal in vacuum, the incident signals with different frequencies are separated into different channels with a contrast ratio of 20 dB. The advantages of this kind of filter are small size and easily tunable operation frequencies.     

Real-time restoration of rotational blurred image using gradient-loading

The key to the restoration of rotational motion blurred image is how to restore the image under a low cost and to correct the irreversibility of the degradation function matrix.Based on the special qualities of degradation function matrix and precise deduction in space-domain, we present a new approach using gradient-loading for restoration of rotational blurred image.By easily adding a gradient operator, the irreversibility of the original matrix is corrected and can be applied for inverse filtering then.Gradientloading is the optimized approach which combines the advantages of both the approaches using constrained least square filtering and traditional diagonal-loading.Compared with the approach using least square filtering, its peak signal-to-noise ratio (PSNR) is improved from 3.18 to 6.46dB, while the computing time is reduced to 1/2-1/3.Experimental results demonstrate the effectiveness, noise-resistibility, robustness, and low complexity of this approach, which make it more suitable for real-time environment.     

All-Optical Logic Device Using Bent Nonlinear Tapered Y-Junction Waveguide Structure

We propose an all-optical logic device made of a bent tapered Y-junction waveguide with a Kerr-type nonlinear interface. It could provide an AND gate, OR gate, and exclusive-OR (XOR) gate. We could obtain different transmission results by adjusting the bending angle. The numerical simulation results show that the device functions as AND, OR, and XOR gates.     

Real-time, continuous-wave terahertz imaging by a pyroelectric camera

Real-time, continuous-wave terahertz (THz) imaging is demonstrated. A 1.89-THz optically-pumped farinfrared laser is used as the illumination source, and a 124 × 124 element room-temperature pyroelectric camera is adopted as the detector. With this setup, THz images through various wrapping materials are shown. The results show that this imaging system has the potential applications in real-time mail and security inspection.