苯并菲衍生物盘状液晶分子的非线性光学与热力学性质

采用密度泛函理论在B3LYP/6-31G**理论水平,计算并研究苯丙炔（烯）酸酯苯并菲盘状液晶分子的偶极矩、非线性光学性质、电子光谱和热力学性质.结果显示,该分子表现出良好的非线性光学性质,其二阶和三阶非线性光学系数分别为10⁴和10⁶a.u.数量级.其最低能量跃迁吸收波长分别为460和474nm,对应π到π*的电子跃迁.在温度298.15 K时,苯丙炔酸酯和苯丙烯酸酯苯并菲衍生物分子的标准摩尔生成焓分别为-7317.06和-1052.68 kJ·mo1^-1,标准摩尔生成自由能分别为-6186.91和117.00 kJ·mol ^-1.     

全氟烃基联苯酯类液晶分子的光谱与热力学性质

使用密度泛函理论在B3LYP/6-311G*水平上计算研究了全氟烃基联苯酯类液晶分子的光谱和热力学性质。结果显示,分子的最低能量激发为HOMO→LUMO的p→p*跃迁, 对应的吸收波长值约为379 nm, 属于近紫外区。在298.15 K和标准压力下,标题化合物分子的生成反应为放热的自发过程,其标准摩尔生成焓与生成自由能分别为-4090.06和-3410.31 kJ.mol-1。     

全氟烃基联苯酯类液晶分子的光谱与热力学性质

使用密度泛函理论在B3LYP/6-311G*水平上计算研究了全氟烃基联苯酯类液晶分子的光谱和热力学性质。结果显示,分子的最低能量激发为HOMO→LUMO的p→p*跃迁, 对应的吸收波长值约为379 nm, 属于近紫外区。在298.15 K和标准压力下,标题化合物分子的生成反应为放热的自发过程,其标准摩尔生成焓与生成自由能分别为-4090.06和-3410.31 kJ.mol-1。     

两种新香豆素分子的热力学和光谱性质

使用密度泛函理论方法在B3LYP /6-31++G**理论水平对两种香豆素a和b分子的几何结构、光谱、热力学性质进行理论计算研究,并基于Tomasi的极化统一场模型(PCM)讨论溶剂效应。结果显示,香豆素a和b分子在气相中的最低能量吸收波长分别为352和355 nm,溶剂及其极性大小对香豆素a最低能量吸收波长影响很小,但在溶剂作用下香豆素b分子的最低能量吸收波长红移7-10 nm,溶剂的极性对该波长影响较小。298 K标准压力下香豆素a和b分子的气态标准摩尔生成焓 分别为-1373.171和-1310.805 kJ.mol-1,标准摩尔生成自由能 分别为-1064.043和-1035.849 kJ.mol-1,标准摩尔熵 分别为763.910和742.150 J.mol-1.K-1.     

含乙酰胺基链苯并菲盘状液晶分子的电荷传输性质与热力学性质

在密度泛函理论B3LYP/6-31G**理论水平上,计算含乙酰胺基链苯并菲衍生物分子的电荷传输性质和热力学性质。研究结果显示,该分子的空穴传输性能明显好于电子传输性能。在298.15 K时,该分子的标准摩尔生成焓和生成自由能分别为-2338.79 kJ/mol和-1756.27 kJ/mol。     

含乙酰胺基链苯并菲盘状液晶分子的电荷传输性质与热力学性质

在密度泛函理论B3LYP／6－31G**理论水平上,计算含乙酰胺基链苯并菲衍生物分子的电荷传输性质和热力学性质.研究结果显示,该分子的空穴传输性能明显好于电子传输性能.在298.15 K时,该分子的标准摩尔生成焓和生成自由能分别为－2338.79 kJ／mol和－1756.27 kJ／mol。     

2,5-二(4-溴甲基苯基)-1,3,4噁二唑分子的结构、光谱与热力学性质的理论研究

采用密度泛函理论在B3LYP/6-31+G*水平计算研究2,5-二(4-溴甲基苯基)-1,3,4噁二唑分子的结构、光谱、热力学性质.结果显示,优化得到的最稳定结构的三个环同在一个平面,两个溴原子偏离平面120°,分别位于平面两端正反方向.气相中最强吸收峰出现在315 nm,为S0到S1的电子跃迁,溶剂作用使其红移4～6 nm.热力学计算表明,标准摩尔焓、标准摩尔热容和标准摩尔熵分别与温度存在二次函数关系.298.15 K,2,5-二(4-溴甲基苯基)-1,3,4噁二唑分子的标准摩尔生成焓和标准摩尔生成自由能分别为2708.95和2972.13kJ.mol-1.     

含酯基和吡啶环苯并菲衍生物分子的电荷传输和三阶非线性光学性质简

采用密度泛函理论在B3LYP/6-31G**理论水平计算研究含酯基和吡啶环的苯并菲衍生物分子的电荷传输速率.结果表明,酯基双取代的苯并菲衍生物分子具有较高的空穴和电子传输速率,分别为0.22cm2/v·s和1.51cm2/v·s.同时引入酯基和吡啶环均不利于空穴和电子传输.使用有限场(FF)方法计算分子的三阶非线性光学性质.结果显示,在酯基和吡啶环之间引入柔性碳链的分子与不含吡啶环分子的三阶非线性光学性质基本一致,均具有较高的电荷传输速率和良好的三阶非线性光学性质.     

含酯基和吡啶环苯并菲衍生物分子的电荷传输和三阶非线性光学性质

采用密度泛函理论在B3LYP/6-31G**理论水平计算研究含酯基和吡啶环的苯并菲衍生物分子的电荷传输速率．结果表明，酯基双取代的苯并菲衍生物分子具有较高的空穴和电子传输速率，分别为0.22 cm2/v•s和1.51 cm2/v•s．同时引入酯基和吡啶环均不利于空穴和电子传输．使用有限场(FF)方法计算分子的三阶非线性光学性质．结果显示，在酯基和吡啶环之间引入柔性碳链的分子与不含吡啶环分子的三阶非线性光学性质基本一致，均具有较高的电荷传输速率和良好的三阶非线性光学性质．     

2,5-二(4-溴甲基苯基)-1,3,4噁二唑分子的光谱

采用密度泛函理论在B3LYP/6-31+G*水平计算研究2,5-二(4-溴甲基苯基)-1,3,4噁二唑分子的结构、光谱、热力学性质.结果显示,优化得到的最稳定结构的三个环构处于同一平面,两个溴原子分别位于平面的上下两侧.气相中最低能量跃迁与最强吸收峰均出现在315 nm,对应HOMO到LUMO的电子跃迁,溶剂作用使其红移4—6 nm.热力学计算表明,标准摩尔焓、标准摩尔热容和标准摩尔熵等热力学性质与温度之间存在很好的二次函数关系.298.15 K,2,5-二(4-溴甲基苯基)-1,3,4噁二唑分子的标准摩尔生成焓和标准摩尔生成自由能分别为2708.95和2972.13 kJ/mol.     

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.     

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.     

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.     

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].     

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.     

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.     

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.