A method for member selection of cross-functional teams using the individual and collaborative performances

The member selection problem is an important aspect of the formation of cross-functional teams (CFTs). Selecting suitable members from a set of candidates will facilitate the successful task accomplishment. In the existing studies of member selection, the individual performance concerning a single candidate is mostly used, whereas the collaborative performance associating with a pair of candidates is overlooked. In this paper, as a solution to this problem, we propose a method for member selection of CFTs, where both the individual performance of candidates and the collaborative performance between candidates are considered. In order to select the desired members, firstly, a multi-objective 0–1 programming model is built using the individual and collaborative performances, which is an NP-hard problem. To solve the model, we develop an improved nondominated sorting genetic algorithm II (INSGA-II). Furthermore, a real example is employed to illustrate the suitability of the proposed method. Additionally, extensive computational experiments to compare INSGA-II with the nondominated sorting genetic algorithm II (NSGA-II) are conducted and much better performance of INSGA-II is observed.     

Optical anisotropy of aligned pentacene molecules on a rubbed polymer corresponding to the electrical anisotropy

We report on the optical anisotropy of a pentacene film on a rubbed (poly)vinylalcohol (PVA) layer related to the electrical performances of the pentacene organic field effect transistors (OFETs) depending on the direction of a current flow. The optical anisotropies of the PVA films are negligible with respect to whether or not rubbing process. In the pentacene OFET on the rubbed PVA layer, however, the optical anisotropy is observed and the anisotropy of the electrical performances directly corresponds to the optical anisotropy of the pentacene thin-film on the rubbed PVA layer.     

中国粤剧旦角发声特性实验研究

戏曲演员发声特性是厅堂音质研究的重要基础数据。为研究中国粤剧旦角演员发声特性,在全消声室内以4位花旦、2位青衣和1位老旦为例,针对念白、清唱和语言三种发声方式,在大、中、小三种发声力度下,分析不同旦角演员在0.3 m处的声压级、动态范围和频率特性曲线,探讨发声特性与发声方式、发声内容、发声力度和行当之间的关系。结果显示在相同的发声力度下,声压级由大到小的发声方式依次为清唱、念白和语言;老旦的动态范围最大,其次是青衣和花旦;清唱内容对发声频率特性曲线影响较小,而发声方式和行当影响较大;演员以不同力度发声时各频率特性曲线形状相似。该文的实验结果将为戏曲厅堂音质设计、建筑物隔声设计和电声系统设计提供科学依据。     

The effects of azo-oxadiazole-based bent-shaped molecules on the temperature range and the light-responsive performance of blue phase liquid crystal

A series of light-responsive azo-oxadiazole-based bent-shaped molecules was synthesised and characterised. Their effects as dopants on the blue phases (BPs) range of the chiral nematic liquid crystal (N*LC) matrix and light-responsive properties including the photo-inducing change of UV absorption properties, photo-adjusting the BP structure as well as the temperature range were investigated. It was found that the azo-oxadiazole-based bent-shaped molecules with branched terminal had better miscibility in LC host than the molecules with straight terminal, and that increasing the length of rigid core of bent-shaped molecules will greatly improve the effect of widening the BP temperature range.     

Computer model investigations on the balance between stage and pit sources in opera houses

The acoustical balance between the singer on the stage and the orchestra in the pit is typically found inside an opera house. The competition of the two sources is crucial, since in an opera the singer and the orchestra are performing at the same time. This topic of balance is receiving increasing attention in recent years, but several aspects are still to be clarified. The aim of this work is twofold: firstly the procedure for the acoustical qualification of the balance between the singer and the orchestra is investigated and secondly the means of controlling the balance at the design stage or during renovations is considered. For both tasks the study was conducted in a group of opera houses modelled within an acoustical CAD program. As regards the qualification of the balance this investigation compares the directional characteristics of two loudspeakers and of a dodecahedron omnidirectional loudspeaker in the emulation of a soprano during simulated room acoustics measurements. It is shown that, in order to emulate a soprano singer, the directional characteristics of the source on the stage are quite important. The control of balance was also studied and the work reserves a special emphasis to the case of historical opera houses. In fact, when such theatres are refurbished, the range of possible architectural interventions is often limited to the orchestra pit only, due to the heritage nature of the hall which prevents from any substantial change in the area of the forestage. For this reason it is important to investigate the effectiveness of such limited interventions in the pit, and this is done here by a detailed study of the effects on balance of some major changes of the orchestra pit only.     

A data hiding approach for the self-security of iris recognition

Attacks to biometric data are the primary danger to the self-security of biometrics. To improve the iris feature template data security, a data hiding approach based on bit streams is proposed, in which an iris feature template is embedded into a face image. The proposed approach is applicable to present dominant techniques of iris recognition. With the low computation cost and the zero decoding-error-rate, this data hiding approach, embedding target biometrie data into other biometrie data for improving the security of target data in identity recognition, data storage and transmission, can deceive attackers more effectively. Furthermore, it does not degrade the iris recognition performances. Experimental results prove that the proposed approach can be used to protect iris feature templates and enhance the security of the iris recognition system itself.     

Effect of buffer layer on thermochromic performances of VO2 films fabricated by magnetron sputtering

As a well-developed industrial fabricating method, magnetron sputtering technique has its distinct advantages for the large-scale production. In order to investigate the effect of buffer layer on the formation and thermochromic performances of VO₂ films, using RF magnetron sputtering method, we fabricated three kinds of buffer layers SiO₂, TiO₂ and SnO₂ on soda lime float-glass. Then according to the reactive DC magnetron sputtering method, VO₂ films were deposited. Due to the restriction of heat treatment temperature when using soda lime float-glass as substrates, dense rutile phase TiO₂ cannot be formed, leading to the formation of vanadium oxide compounds containing Na ions. When using SnO₂ as buffer layer, we found that relatively high pure VO₂ can be deposited more easily. In addition, compared with the effect of SiO₂ buffer layer, we observed an enhanced visible transparency, a decreased infrared emissivity, which should be mainly originated from the modified morphology and/or the hetero-structured VO₂/SnO₂ interface.     

Vibrational computations beyond the harmonic approximation: performances of the B3LYP density functional for semirigid molecules

The performances of the B3LYP density functional in the computation of harmonic and anharmonic frequencies were tested using 14 standard basis sets of double and triple zeta quality for a set of semirigid molecules containing from 4 to 12 atoms. The quality of the results is assessed by comparison with the most reliable computations available in the literature. The study reveals that the relatively cheap 6-31+G(d,p) basis set performs a very good job for harmonic frequency calculations and that B3LYP anharmonicities are in close agreement with the reference values irrespective of the basis set used. On these grounds "hybrid force fields" are proposed to achieve the best compromise between computer time and quality of the results.     

Searching for high performance asymmetrically substituted teterazine energetic materials based on 3-hydrazino-6-(1H-1,2,3,4-tetrazol-5-ylimino)-s-tetrazine

Tetrazine compounds are promising candidates of high performance energetic materials (EMs). For the purpose of exploring high performance asymmetrically substituted teterazine explosives, 3-hydrazino-6-(1H-1,2,3,4-tetrazol-5-ylimino)-s-tetrazine was selected as the precursor and a series of teterazine EMs were prepared based on three synthetic strategies. All the obtained compounds were fully characterized and the crystal structures of seven compounds were further confirmed by single crystal X-ray diffraction. The thermal dynamics and thermal safety parameters, the detonation properties and impact sensitivities were also obtained. The results revealed that compounds 15–17 show excellent energetic properties (detonation velocities > 9000 m·s^?1, detonation pressures > 30 GPa) and have impact sensitivities (8–12 J) that comparable or lower than RDX. Compounds 9–13 are insensitive to impact and have detonation velocities range from 8452 to 8775 m·s^?1. These compounds can be good candidates of high performance secondary explosives or insensitive EMs.     

Effect of carbon black on the mechanical performances of magnetorheological elastomers

Several magnetorheological elastomer (MRE) samples, with different weight percentages of carbon black, were fabricated under a constant magnetic field. Their microstructures were observed by using an environmental scanning electron microscope (SEM), and their mechanical performance including magnetorheological (MR) effect, damping ratio and tensile strength were measured with a dynamic mechanical analyzer (DMA) system and an electronic tensile machine. The experimental results demonstrate that carbon black plays a significant role in improving the mechanical performance of MR elastomers. Besides the merits of high MR effect and good tensile strength, the damping ratio of such materials is much reduced. This is expected to solve a big problem in the application of MR elastomers in practical devices, such as in adaptive tuned vibration absorbers.