Thermal expansion coefficient is a regular coefficient to describe the variation of geometric characteristics of matter under the action of thermal expansion and cold shrinkage effect, and it is an important index to measure the thermal stability of materials. A device for measuring the thermal expansion coefficient of solid materials by Yang’s double slit interferometric method with variable double slit spacing is mainly composed of laser, sliding Young double slit structure, temperature measuring and controlling instrument, shading tube, receiving device and solid material to be measured. The solid material is heated by ring heater, the temperature of solid material is displayed and controlled by temperature measuring and controlling instrument, and the change of stripe spacing is recorded by linear CCD image sensor. Compared with the traditional optical leverage method, this measuring device and method can significantly improve the accuracy of the measurement results and reduce the uncertainty of the measurement results.

The ZnO micro-nanorods are controlledly synthesized by a simple chemical vapor deposition method. With different oxygen concentrations the micro-nanorods exhibit different extrinsic feature and length. Under lower oxygen concentration, the micro-nanorods are up to 1670 μm in length which can be easily operated in singlecrystalline. When the oxygen concentration up to 30 sccm, the surface of the sample is smoother. The Raman spectra reveal that ZnO micro-nanorods have an excellent hexagonal wurtzite structure. However, the micronanorods synthesized during lower oxygen concentration exhibit more oxygen defect. The morphology controlling deposition of ZnO mircro-nanorods were realized by adjust the concentration of oxygen, which has great significance for further gas sensor application.

The ZnO nanocrystalline was deposited on quartz substrate by a CVD method. Our investigation proves that the morphology-controlled deposition of nanocrystalline can be realized by adjusting the substrate temperature. The nanocrystalline consisted of nanorods, nanobulks and nanowires. It turns out that higher temperatures are more favorable for the foration of nanorods and nanowires, while lower ones promote the formation of nanobulks. The SEM and XRD methods were used to characterize the microstructural properties of the sample. The produced nanorods were about 6.25-28.25 mu m in length with great uniformity. An intense 002 peak was observed, which indicated that nanorods had a strongly pronounced hexagonal wurtzite structure, while the lattice parameter was very close to its theoretical value.

The chemical vapor deposition technique was used to prepare the Ag doped ZnO microrods, which were located on Si substrates at two different positions. The scanning electron microscopy revealed that the samples have a clear hexagonal shape. X-ray diffraction provided information about the preferential orientation along the c-axis. The Raman analysis revealed that a new Raman mode appears at 492 cm-1 due to Ag doping. As this mode has not been reported early, it could be used as a characteristic mode of Ag doping in Raman spectrum. The red shift of the E2 (high) mode proves the existence of tensile stress in the samples. DOI: http://dx.doi.org/10.5755/j01.ms.25.3.19130

The ZnO nanorods are synthesized by a typical CVD method without any catalyze and substrate. The concentration of nitrogen is changed by a digital gas control system. The influence on the morphology is studied in detail. Under lower amounts of nitrogen the diameter of nanorod is smaller than in the higher one. Meanwhile, the size of the nanorod is bigger in the rich nitrogen amounts. The morphology of the sample is carry out by SEM, and the crystal structure information is giving by XRD. All the measurement told that the nanorods have a great hexagonal wurtzite structure.

Because of the different melting point, it is difficult to doped Ag element in ZnO film. Ag dopant can adjust the properties of ZnO materials. In this paper, we deposited Ag doped ZnO film using two step vapour evaporation method on c-plane sapphire substrate. The SEM image shows that the doped film was composed of small grain which compact in order and the Ag microwires was dispersed on the surface. The EDX graph proves that the Ag was indeed in the film. The XRD pattern reveals that the doped film has prefer orientation along the c-axis with wurtzite structure and the dopants have not effect the crystal quality.

High entropy alloy (HEA) thin coatings have been deposited on steel substrate of a mixed alloy power made of high purity elemental aluminium, cobalt, chromium, copper, iron and nickel by electron beam evaporation and effects of the Al content of the coating on its structure, surface morphology and electrical properties were investigated. The results of X-ray diffraction (XRD) show that coatings are typical dendrite and interdendrite structures with different aluminum contents. The coatings' surface chemical components are basically similar to originally designed alloys by electron probe micro-analyzer (EPMA). Atomic force microscopy (AFM) results indicate that the modified surface of all coatings are very smooth and uniform. HEA coatings exhibit wide passive regions>700 mV in aqueous solutions of H2SO4 and NaCl. A large corrosion potential (−129 mV) and a small corrosion current density (≈2.2×10−6 A/cm2) clearly reveals that the corrosion resistance of the Al0.5FeCoCrNiCu coating is superior to that of the coatings.

The Ag doped ZnO films were prepared on sapphire substrates using simple thermal evaporation method. The effect of annealing treatment was investigated in detail. The results shows that the annealed Ag doped ZnO film has a prefer orientation along c-axis. The E-2 (high) mode in Raman spectra has a little blue shift which caused by crystal defects oxygen vacancies, meanwhile the compressive stress was exist in the film. After annealed, the intense of E-2 modes have great improvement which means the quality of the film was enhanced, meanwhile, the compressive stress released to some extent.

We present a theoretical investigation of the aggregation effects of two 4H-Pyran-4-ylidene-based organic sensitizers on the TiO2(1 01) surface, which are used in dye-sensitized solar cells (DSSCs). Our results combining density functional theory (DFT), time-dependent OFT, and density functional tight binding (DFTB) methods show that 4H-Pyran-4-ylidene-based organic sensitizers are prone to aggregate on the TiO2 surface due to the strong intermolecular pi...pi interactions. The aggregation has obvious effects on electronic structures and absorption spectra of the organic sensitizers. The incorporation of an electron-deficient benzothiadiazole (BT) unit in the spacer part of the organic dye leads to a broader absorption band in the red portion of the UV visible spectra, which is desirable for enhanced spectral responses. However, the BT moiety also leads to more aggregation on the TiO2 surface and stronger electron coupling within the dimers, which might retard the electron transfer at the dye-TiO2 interface and therefore limit the photovoltaic efficiency. This study sheds light on the aggregation effects of metal-free organic dyes and is expected to assist in the rational design of novel and efficient all-organic sensitizers for the further optimization of DSSCs. (C) 2016 Elsevier B.V. All rights reserved.

We reported density functional studies of the structure and thermodynamics of NaMgH3 in the cubic perovskite structure as well as corresponding fluorides. Analyses of the calculation results in terms of formation enthalpies, substitution enthalpies, reaction enthalpies showed that partial H were replaced with halogen in catalyst which improved thermodynamic properties, facilitate dehydrogenation of hydrides. The obtained calculation results suggested that halide-doped in NaMgH3 may result in a favorable thermodynamics modification, and accordingly result in a favorable modification for onboard hydrogen storage application.

Ag doped ZnO microrods are prepared on c-plane sapphire substrates by chemical vapour deposition method at high temperature.The morphology, structure and optical properties were investigated by scanning electron microscopy, X-ray diffraction and Raman spectrum, respectively. The prepared Ag doped ZnO microrods have good preferred orientation with very limited structural defects. The Raman bands indicates that a tensile stress existed in the sample and an additional local vibrational mode related to Ag is also found which can be used to confirm the existence of Ag in the Ag doped ZnO microrods.