High-Q and Tailorable Fano Resonances in a One-Dimensional Metal-Optical Tamm State Structure: From a Narrowband Perfect Absorber to a Narrowband Perfect Reflector

Fano resonances giving rise to a rich variety of asymmetric spectral shapes have been investigated in optical nanostructures with multidimensional configurations. However, 1D nanostructure realizing Fano resonances with well-controlled spectral shapes are yet to be demonstrated. Here, the authors present both numerically and experimentally a 1D nanostructure exhibiting rich Fano resonances induced by interference between a lossy background (continuum) provided by a metal thin film and a discrete optical Tamm state (OTS). A drastic change in the Fano line shape occurs from a narrowband perfect absorber into a narrowband perfect reflector by controlling the metal thin film. Independent from the metal-related Fano profile, the OTS component determines the resonance frequency and guarantees a sharp resonance (with quality factors over 1000) on the flat mirror background. Taking advantage of its high-Q property, the structure can be developed into a dispersion device with subnanometer spectral resolution, which even enables a direct imaging of spectral information of molecular fingerprint. The authors believe that this work not only demonstrates a planar nanostructure with versatile Fano resonances for various applications but also provides physical insights into how a metal thin film can induce and significantly affect the Fano resonances in 1D optical resonators.     

Sufficient Conditions for Stability of Periodic Linear Impulsive Delay Systems

For a linear periodic system with impulsive action and delay, new approaches to the study of stability were proposed on the basis of the methods of spectral theory of linear operators, direct Lyapunov method, and N.G. Chetaev method for construction of the Lyapunov functions for the periodic linear systems, as well as the perturbation method for construction of the Lyapunov functions. These methods underlie the sufficient conditions for asymptotic stability of the linear periodic systems with impulsive action and delay. We gave some illustrative examples of studying stability of such systems under different assumptions about the dynamic properties of the continuous and discrete components of the impulsive system.     

Enhancing strength and hardness of AZ31B through simultaneous addition of nickel and nano-Al2O3 particulates

In the present study, AZ31B-Al₂O₃-Ni composites are developed by the addition of different amounts of Ni particulates into AZ31B-1.5Al₂O₃ using disintegrated melt deposition technique followed by hot extrusion. The AZ31B-1.5Al₂O₃ nano-composite is known to exhibit excellent ductility (∼30%) matching with that of pure aluminum but its strength levels are compromised. The composites developed in the current study show a homogeneous microstructure and significant improvement in mechanical characteristics. The results of mechanical properties characterization reveal that addition of Ni led to a simultaneous improvement in 0.2% YS (up to 25%), UTS (up to 13%) and hardness (up to 62%). The ductility, however, stayed almost similar to the ductility of monolithic AZ31B in the case of AZ31B-1.5Al₂O₃-1.5Ni composite while it was compromised for AZ31B-1.5Al₂O₃-3.19Ni. The results clearly reveal the superior capability of AZ31B-Al₂O₃-Ni formulations in terms of overall mechanical response when compared to monolithic AZ31B.     

拉索风雨激振的多模态耦合及面内-面外振动

在假设拉索表面与水线之间作用着库仑阻尼力和粘滞线性阻尼力的基础上,建立了能够反映拉索面内-面外振动的带运动水线的连续弹性拉索风雨激振理论模型。通过振型分解,获得了以拉索面内-面外各阶模态表示的拉索运动微分方程。利用该理论模型对洞庭湖大桥S19拉索进行了分析,结果表明：拉索风雨激振是多模态的耦合振动,振动过程中伴随着模态的转移;面内振动和面外振动同时发生,通常情况下面内振动占据优势;拉索截面运动的轨迹是一个斜置椭圆,或是几个斜置椭圆交织在一起;风速对拉索振动偏振角有较大影响;拉索最大振幅发生的位置随参振模态的变化而改变     

Isolation and characterization of a multienzyme complex (cellulosome) of the Paenibacillus curdlanolyticus B-6 grown on Avicel under aerobic conditions

A multienzyme complex, cellulosome, of the facultatively anaerobic bacterium, Paenibacillus curdlanolyticus B-6 was produced on microcrystalline cellulose (Avicel) under aerobic conditions. During growth on Avicel, the bacterial cells were found to be capable of adhesion to Avicel by scanning electron microscopic (SEM) analysis. The multienzyme complex of P. curdlanolyticus B-6 was isolated from the crude enzyme preparation by gel filtration chromatography on Sephacryl S-300 and affinity purification on cellulose. The isolated multienzyme complex was able to bind to both Avicel and insoluble xylan and consists of cellulolytic and xylanolytic enzymes such as avicelase, carboxymethyl cellulase (CMCase), cellobiohydrolase, β-glucosidase, xylanase, β-xylosidase and α-l-arabinofuranosidase. The molecular mass of the complex was estimated to be 1600 kDa. It composed of at least 12 proteins on SDS-PAGE and 10 CMCases and 11 xylanases on zymograms. The isolated multienzyme complex could degrade the raw lignocellulosic substances effectively.     

我国汽车尾气净化稀土催化剂研究现状及展望

综述我国汽车尾气净化催化剂研究开发现状 ,指出了现有稀土催化剂存在的不足 ,展望了未来的发展方向。     

几何形误差对气体静压圆柱轴承运动精度的影响

几何形误差是影响气体静压圆柱轴承运动精度的主要因素之一。本文从理论上研究了气体轴承副零件因加工过程中形成的几何形误差对气体静压圆柱轴承运动精度的影响,并且,对轴颈具有加工误差时气体静压圆柱轴承的运动精度进行了研究,给出了轴颈的几何形误差与轴承运动精度关系的表达式,为轴承运动精度的理论分析提供了可靠的依据。     

陆相盆地重质油成因类型及其稠变序列——以二连盆地为例

应用二连盆地重质油物性和地球化学分析资料,结合其他盆地重质油典型实例,系统阐述了重质油形成的主控因素。研究表明,重质油成因类型可分为原生重质油和次生重质油,前者来自有机质在热演化过程中所生成的未熟-低熟油,后者则是石油(常规油或普通重质油)进入储层聚集成藏后,由于保存条件差异,受各种稠变作用形成的高密度、高黏度重质油。重质油形成所经历的稠变作用主要包括生物降解、水洗、氧化、裂解致稠和运移-聚集分异等作用。在石油运移、聚集和保存阶段,上述多种稠变因素总是交织、叠加在一起,只有在某些特定地质环境下,单个稠变因素才表现得相对突出。多数盆地或地区重质油的形成以生物降解占主导作用,其次为氧化、水洗、裂解致稠以及运移-聚集分异等作用。基于二连盆地及其他盆地重质油黏度数据分析,归纳出重质油的稠变序列为,低成熟重质油(黏度100~500 mPa·s)、未成熟重质油(黏度500~1 000 mPa·s)、轻度生物降解重质油(黏度800~2 000 mPa·s)、中度生物降解重质油(黏度2 000~20 000 mPa·s)、重度生物降解重质油(黏度20 000~100 000 mPa·s)、超重度生物降解重质油(黏度大于100 000 mPa·s)。其中,轻度生物降解重质油为普通重质油;中度生物降解重质油达到普通重质油-特重质油;重度生物降解重质油为特重质油;超重度生物降解重质油为超重质油。