不同V型辅助配体构筑的两个镉配位聚合物的合成、结构和荧光性质

在溶剂热条件下，合成了 2 个基于 V 型辅助配体(bipmo、bppmo)的镉配位聚合物{[Cd(bipmo)(NDC)]·1.75H₂O}_n (1)和{[Cd(bppmo)(NDC)(H₂O)]·H₂O}_n (2)，其中 H2NDC=2，6 萘二羧酸，bipmo=双(4 (1H 咪唑 1 基)苯基)甲酮，bppmo=双(4 (吡啶 4 基)苯基)甲酮。利用单晶X射线衍射、键价和分析、红外光谱和元素分析对其结构进行了表征。研究发现，配合物1具有二重互穿的{63}拓扑结构。配合物2同样是 3 连接的{6³}拓扑，却存在三重穿插结构。分析表明，V型配体对最终结构的形成有很大影响。此外，对配合物1和2的发光性质也进行了详细研究。     

Large eddy simulation of turbulent premixed and stratified combustion using flame surface density model coupled with tabulation method

Large eddy simulations (LESs) are performed to investigate the Cambridge premixed and stratified flames, SwB1 and SwB5, respectively. The flame surface density (FSD) model incorporated with two different wrinkling factor models, i.e., the Muppala and Charlette2 wrinkling factor models, is used to describe combustion/turbulence interaction, and the flamelet generated manifolds (FGM) method is employed to determine major scalars. This coupled sub-grid scale (SGS) combustion model is named as the FSD-FGM model. The FGM method can provide the detailed species in the flame which cannot be obtained from the origin FSD model. The LES results show that the FSD-FGM model has the ability of describing flame propagation, especially for stratified flames. The Charlette2 wrinkling factor model performs better than the Muppala wrinkling factor model in predicting the flame surface area change by the turbulence. The combustion characteristics are analyzed in detail by the flame index and probability distributions of the equivalence ratio and the orientation angle, which confirms that for the investigated stratified flame, the dominant combustion modes in the upstream and downstream regions are the premixed mode and the back-supported mode, respectively.     

黏性流体环境下V型悬臂梁结构流固耦合振动特性研究

V型悬臂梁结构在原子力显微镜、微纳机械传感器件中得到了广泛应用, 该结构通常在黏性流体环境下实现精密检测、传感与性能表征,同时也会使得结构的流固耦合振动特性更为复杂, 直接影响器件的动态性能.本文针对V型结构变截面、变刚度等复杂几何特征, 建立了黏性流体环境下V型悬臂梁结构的流固耦合动力学模型, 导出了基于截面孔宽比参数的梁结构的修正水动力函数, 确定了截面孔宽比和频率参数影响下V型悬臂梁结构的水动力函数;理论分析得到了黏性流体中V型梁结构的频率响应特性.同时, 设计了多种不同几何尺寸的V型梁结构, 并在水环境中开展了实验验证, 结果表明, 实验所得频率响应与理论分析结果吻合较好, 验证了V型梁结构水动力函数修正表达式及流固耦合动力学模型.此外, 基于该流固耦合动力学模型, 详细分析了不同流体黏度、V 型梁角度及尺寸变化对耦合系统振动特性的影响.      

Enhanced optical transmission by V-shaped nanoslit in metal film

In this paper,we reveal that the enhanced transmission through a perforated metal film can be further boosted up by a V-shaped nanoslit,which consists of two connected oblique slits.The maximum transmission at resonance can be enhanced significantly by 71.5%in comparison with the corresponding vertical slit with the same exit width.The value and position of transmission resonance peak strongly depend on the apex angle of the V-shaped slit.The optimum apex angle,at which the transmission is maximal,is sensitive to the slit width.Such phenomena can be well explained by a concrete picture in which the incident wave drives free electrons on the slit walls.Moreover,we also simply analyze the splitting of the transmission peak in the symmetry broken V-shaped slit,originating from the resonances of different parts of the V-shaped slit.We expect that our findings will be used to design the nanoscale light sources based on the metal nanoslit structures.     

静电场对V型火焰法中碳纳米管定向生长的影响

针对V型火焰实验系统的特点,考察了在种不同的静电场引入方式,以及在5V、30V和150V三种偏置电压下碳纳米管的定向生长情况.对实验结果进行了SEM、TEM表征,验证了静电场对碳纳米管定向生长的诱导作用,同时发现在一定范围内,随着偏置电压的增人,碳纳米管的准直性生长越明显.     

V型夹层炸药对射流干扰的数值模拟

采用三维有限元程序(LS-DYNA)模拟了射流侵彻放有V型夹层炸药靶板的过程,并与无V型夹层炸药等情况进行了对比。V型夹层炸药爆炸后,运动的两组面板和背板对射流有严重的干扰和切割效应,导致射流偏转、弯曲、着靶点分散,使射流的侵彻深度下降约30%～90%,V型夹层炸药结构干扰程度随入射角度的增大而呈递增趋势。V型角的变化对射流的侵彻深度干扰作用不明显。     

Processing of Diamond for Integrated Optic Devices Using Q-Switched Nd:YAG Laser at Different Wavelengths

In the present investigation, a Q-switched Nd:YAG laser is used to study the various aspects of diamond processing for fabricating integrated optic and UV optoelectronic devices. Diamond is a better choice of substrate compared to silicon and gallium arsenide for the fabrication of waveguides to perform operations such as modulation, switching, multiplexing, and filtering, particularly in the ultraviolet spectrum. The experimental setup of the present investigation consists of two Q-Switched Nd:YAG lasers capable of operating at wavelengths of 1064 nm and 532 nm. The diamond cutting is performed using these two wavelengths by making the “V”-shaped groove with various opening angle. The variation of material loss of diamond during cutting is noted for the two wavelengths. The cut surface morphology and elemental and structural analysis of graphite formed during processing in both cases are compared using scanning electron microscopy (SEM) and laser Raman spectroscopy. Both the Q-Switched Nd:YAG laser systems (at 1064 nm and 532 nm) show very good performance in terms of peak-to-peak output stability, minimal spot diameter, smaller divergence angle, higher peak power in Q-switched mode, and good fundamental TEM₀₀ mode quality for processing natural diamond stones. Less material loss and minimal micro cracks are achieved with wavelength 532 nm whereas a better diamond cut surface is achieved with processing at 1064 nm with minimum roughness.     

The problem of multivariate classification of samples with radial (or V-shaped) chemical data

On the basis of the results of previous studies, the problem of multivariate classification in the presence of the so-called radial or V-shaped data has been briefly re-examined. Taking into account that the radial data, in the absence of preliminary transformations, usually lead to classifications of samples meaningless from a chemical point of view, five different data transformations have been evaluated and compared in the case of both hypothetical and real samples (real samples, in particular, consisted of archaeological ceramic shards to be classified on the basis of provenance). The following transformations have been used: closure to 100, log row centering, log double centering, row centering, and double centering. The transformed data were then classified by means of hierarchical clustering and principal component analysis (PCA). It has been demonstrated that only the first three transformations lead to correct classifications of radial data, and the causes of this fact have been explained.     

基于快速傅里叶变换的条纹图像处理研究

为提高船体扭转角变形测量精度,对双光栅干涉测量法产生的莫尔条纹采用快速傅里叶变换频域处理。采集不同宽度的莫尔条纹图像,分别对图像进行快速傅里叶变换,对比分析图像频谱,得到实际莫尔条纹图像的有效频率信息。分析滤波器的选择原则,选用陷波低通滤波器,去除频域图像中高频噪声,获得莫尔条纹有效信息。实验结果表明,莫尔条纹的频域处理精度远高于空域处理结果,使扭转角测量精度提高到1.2″。     

碲、硒碲合金纳米线的可控合成

"采用一种新的化学溶液法合成了具有不同形貌的碲、硒碲合金纳米线．用十二烷基苯磺酸钠作为表面活性剂实现了对纳米线的可控合成,通过控制反应过程可以弯曲状、"V"字型的硒碲纳米线,利用XRD、TEM以及HRTEM对纳米线的形貌结构特征进行表征;以实验结果为依据讨论了纳米线的生长机理．"