Fabrication,structural and vibrational properties,and physical and optical properties tailoring of nanocrystalline MoS2 films

The modification and tuning features of nanostructured films are of great interest because of controllable and distinctive inherent properties in these materials. Here, nanocrystalline MoS₂ films were fabricated on the stainless steels by a radio frequency magnetron sputtering at ambient temperature. X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and Raman scattering spectroscopy were used to study the chemical state, chemical composition, crystal structure and vibrational properties of the fabricated MoS₂ films. The bias voltage dependent structural evolution and its influence on the optical properties of MoS₂ nanocrystalline films were systematically investigated. Besides, the residual stresses of MoS₂ nanocrystalline films were explored by employing sin²ψ approach. X-ray diffraction demonstrates that the nanocrystalline MoS₂ films have single-phase hexagonal crystal structure. All MoS₂ films are polycrystalline in nature. The bandgap values are found to be intensively dependent on bias voltage. Our findings show that the nanocrystalline MoS₂ films with different physical properties and intense quantum confinement effect can be realized through adjusting bias voltages. This work may provide deep insight for realizing transitional metal dichalcogenide-based nanostructured film optoelectronic devices with tunable physical properties through a traditional, very cost-effective, and large-scale fabrication method.     

物理化学课程的创新教学模式研究及其效果分析

物理化学课程创新教学模式是以学生学习为中心,吐故纳新,优化精选,以新颖或变化的教学方式进行教学。调查表明创新教学模式受到绝大多数学生的肯定和认可,有效地调动学生的积极性,提高了学生对物理化学的学习和探究兴趣,学生提问问题的广度和难度发生显著变化。该教学模式能够逐步提升学生的创新意识和创新能力。     

The benefit of being physically present: A survey of experimental works comparing copresent robots,telepresent robots and virtual agents

The effects of physical embodiment and physical presence were explored through a survey of 33 experimental works comparing how people interacted with physical robots and virtual agents. A qualitative assessment of the direction of quantitative effects demonstrated that robots were more persuasive and perceived more positively when physically present in a user׳s environment than when digitally-displayed on a screen either as a video feed of the same robot or as a virtual character analog; robots also led to better user performance when they were collocated as opposed to shown via video on a screen. However, participants did not respond differently to physical robots and virtual agents when both were displayed digitally on a screen – suggesting that physical presence, rather than physical embodiment, characterizes people׳s responses to social robots. Implications for understanding psychological response to physical and virtual agents and for methodological design are discussed.     

High Temperature Property Development of Bauxite Based Bricks

Physical properties and microstructural evolution on firing of 3 types of bauxite based refractory bricks were carried out using techniques such as porosimetry,XRD and SEM.The groups differed from each other by progressive refining of the matrix or bond phase.It is revealed that such a refinement of the matrix can improve the high temperature properties of the bricks made from poor grade materials.     

Influence of iron oxide pigments on the properties of concrete interlocking blocks

Concrete interlocking blocks (CIBs) are utilized in a variety of commercial, municipal, and industrial applications. Superior engineering properties, low maintenance, ease of placement and removal, reuse of original blocks, aesthetic appeal, and immediate availability are the primary reasons for choosing concrete block pavement over other paving surfaces. It is a common practice to pigment building materials, such as mortar, concrete pavers, concrete roof tiles, and prefabricated concrete products; CIBs are colored using iron oxide pigments. This article presents experimental results detailing the properties of CIBs dyed with pigments. The results of these experiments are as follows: Because the particles of iron oxide pigments are finer than those of brown iron oxide, interlocking blocks mixed with the former acquired higher color strength than with the latter. Additional analysis determined a definite relationship between the flexural strength and the absorption ratio of pigment-dyed blocks; the correlation coefficient (R²) of interlocking blocks at 91 days was .90. It is suggested that if iron oxide pigments are to be used to color CIBs, the pigment-to-cement ratio should be below 4%.     

氧化钨物理特征的测量

对铵钨青铜（ATB）、氢钨青铜（HTB），紫色氧化钨（TVO）和蓝色氧化钨（TBO）四种氧化钨粉的氮气吸附/脱附等温线数据的分析。可以得出其表面积，微孔体积，微孔分布，中孔体积，平均孔径和分数维数。吸附/脱附等温线数据的分析表明，TVO粉末具有最大的中孔体积，最小的微孔体积，最窄的孔径分布，最小的分数维数和最大的平均孔径，其有利于氢还原制取超细钨粉，而不利于掺杂工艺，HTB粉末具有最大的微孔体积，最宽的孔径分布，最高的分数维数和最小的平均孔径，对于掺杂工艺来说是有利的，ATB和ABO的上述参数界于TVO和HTB之间。结果表明，利用吸附/脱附等温线来研究氧化物的物理特征是一个很好的方法；在氧化钨用于氢还原工艺和掺杂工艺之前必须研究其物理特征。     

A polydispersed particle system representation of the porosity for non-saturated cementitious materials

In this paper, the porosity of cementitious materials is described in terms of pore size distribution by means of a 3-dimensional overlapping sphere system with polydispersivity in size. On the basis of results established by Lu and Torquato [B. Lu, S. Torquato, Nearest-surface distribution functions for polydispersed particle systems, Phys. Rev. A 45(8) (1992) 5530-5544] and Torquato [S. Torquato, Random Heterogeneous Media: Microstructure and Macroscopic Properties. Springer-Verlag: New York, 2001] providing relations for nearest-neighbor distribution functions, the volume fraction of pores having a radius larger than a prescribed value is explicitly expressed. By adopting an appropriate size distribution function for the sphere system, it is shown that the pore size distribution of cementitious materials as detected for instance by mercury intrusion porosimetry (MIP), which generally points out several pore classes, can be well approached. On the basis of this porosity representation, the evaluation of the capillary pressure in function of the saturation degree is provided. The model is then applied to the simulation of the saturation degree versus relative humidity adsorption curves. The impact of the pore size distribution, the temperature and the thickness of the adsorbed water layer on these parameters are assessed and analyzed for three model materials having different pore characteristics.     

大型空分设备循环冷却水处理方法的对比研究

武钢氧气公司在大型空分设备循环冷却水系统中,采用化学法和物理法进行水处理效果的实践探索,从原理和监测数据上进行了对比、分析研究,确认物理法具有高效除垢、防垢、杀菌灭藻、缓蚀以及净化等功能,可以取代化学法进行循环水处理。     

HART协议物理层设备的测试（II）

本文介绍HART协议物理层设备的测试要求、测试设备、测试方法及测试时的一些特别说明。     

一种用于卫星电视接收的FZP天线

本文用物理光学法对ＦＺＰ反射器的聚焦场、聚焦效率及偏轴扫描特性等进行初步分析，并由此提出一种使用ＦＺＰ天线实现多颗卫星信号同时接收的技术方案。原理性样机实际接收结果证实了其可行性