Electron and positron energy distributions in Cd0.5Mn0.5Te alloy

We calculated the electron and positron band structure for Cd_0.5Mn_0.5Te alloy and presented electron and positron charge densities as a function of position in the unit cell. The densities of states both electronic and positronic at different points of reciprocal space were performed. In these calculations, we used the empirical pseudopotential method and the virtual crystal approximation coupled with the independent particle model.     

The effect of glass bead content on the mechanical properties of acrylonitrile/styrene/acrylate copolymer

The influence of glass bead content and the loading rate on the mechanical properties of polyacrylonitrile/styrene acrylate (ASA) copolymer was investigated. For this copolymer, tensile yield strength and work to fracture were significantly reduced as the bead content was increased. Tensile yield strength decreased linearly with increasing glass bead content according to the Leinder equation. It was found that the variation of tensile yield strength with log (loading rate) follows that of Eyring's equation for yielding. The presence of the weldline reduced the tensile yield strength of both unfilled and filled materials. Flexural modulus and flexural strength also varied in a predictable fashion with glass bead concentration. The increase in modulus with glass bead content followed Kerner's equation.Crack growth resistance values of the unfilled ASA and its composites were measured at three loading rates using the generalized locus method. It was found that the resistance to steady crack propagation,J _R, was a sensitive function of glass bead content and loading rate. Within the range of these experiments,J _R decreased with increasing glass bead content and loading rate.     

Thermal diffusivity measurement of CVD diamond film using a step heating technique

A step heating method for the measurement of the thermal diffusivity of diamond thin film is described. The step heating method is a transient heat flow method. Transient temperature profiles are generated in a strip-shaped sample by heating one end of the sample while the other end is clamped to a heat sink. Three thermocouples are used along the heat path. The results are compared with the literature values over the temperature range from –190 to 50°C.     

Effect of electrodeposition and annealing of ZnO on optical and photovoltaic properties of the p-Cu2O/n-ZnO solar cells

Cu₂O/ZnO p–n heterojunction solar cells were fabricated by rf sputtering deposition of n-ZnO layer, followed by electrodeposition of p-Cu₂O layer. The different electrodeposition potentials were applied to deposit Cu₂O on ZnO. The particle size, crystal faces, crystallinity of Cu₂O is important factor which determine the p–n junction interface and consequently their effect on the performance of the heterojunction solar cell. It is observed that at −0.6 V, p-Cu₂O film generates fewer surface states in the interband region due to the termination of [1 1 0] resulting in higher efficiency (0.24%) with maximum particle size (53 nm). The bandgap of Cu₂O at this potential is found to be 2.17 eV. Furthermore, annealing of ZnO film was performed to get rid of deteriorating one and two dimensional defects, which always reduce the performance of solar cell significantly. We found that the solar cell performance efficiency is nearly doubled by increasing the annealing temperature of ZnO thin films due to increasing electrical conductance and electron mobility. Doping studies and fine tuning of the junction morphology will be necessary to further improve the performance of Cu₂O/ZnO heterojunction solar cells.     

生物植入用碳纳米管增强混合功能梯度材料的力学性能(英文)

利用羟基磷灰石(HA)、不锈钢316L(SS316L)和碳纳米管(CNT)制备生物医学植入体用混合功能梯度材料(FGM)。加入SS316L和CNT增强功能梯度材料离散层的HA制成三种不同类型的功能梯度材料。第一种功能梯度材料加入10%~40%(质量分数)的SS316L强化微米HA,浓度梯度为10%。第二种功能梯度材料,在第一种功能梯度材料的基础上加入0.5%(质量分数)的功能化碳纳米管。第三种功能梯度材料在第二种功能梯度材料的基础上加入微米HA和纳米HA(1:1)的混合物。所有类型的功能梯度材料在相似的压缩参数和烧结参数下,进行单轴压缩实验,并采用无压烧结技术进行烧结。结果表明,加入碳纳米管和纳米晶体HA提高了功能梯度材料的致密度。碳纳米管增强的功能梯度材料的硬度和断裂韧性增加,但是微米和纳米晶体HA增强的功能梯度材料的硬度和断裂韧性的增加更明显。     

CuS-functionalized cellulose based aerogel as biocatalyst for removal of organic dye

CuS-functionalized cellulose based aerogel (CBA) with 3D macroporous structure was synthesized by in situ deposition of visible light responsive CuS photocatalyst. Hexagonal CuS was deposited onto the outer and inner walls of CBA matrix. CuS/CBA composite catalyst has hierarchical porous structure and abundance in functional groups supporting CuS on CBA surface that enhance photodecomposition of methylene blue (MB). The CuS/CBA composite was characterized by XRD, FTIR, SEM-EDS, Atomic Absorption Analysis, and XPS analysis. Photodegradation rate of MB by CuS/CBA composite catalyst in visible light was 94.1%, whereas, 67.4% for pure CuS. Initial MB concentration effects, pH change, and variations in CuS/CBA dosage on overall reaction kinetics were also studied. CuS/CBA composite catalyst carried out Photo-Fenton like reactions which decomposed 97% MB within 6 min, by producing hydroxyl radicals from chemical and photocatalytic reactions. CuS/CBA composite catalyst was recycled and reused. It retained over 80% MB degradation rate even after five consecutive cycles. CuS/CBA composite can be used as biocatalyst for removal of organic dyes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47404.     

Fabrication of heterogeneous photocatalysts for insight role of carbon nanofibre in hierarchical WO3/ MoSe2 composite for enhanced photocatalytic hydrogen generation

Mimicking the natural photosynthesis system, artificial photocatalysis facilitates effective utilization of solar energy for environmental sustainability and hydrogen energy production. In this work, the robust and efficient carbon fiber has been successfully incorporated into the interface between WO₃ nanodots and MoSe₂ needles using the facile hydrothermal and solvothermal method. The suitable interfacial contact of heterogeneous photocatalysts plays a significant role in the separation/transfer of interfacial photogenerated electron-hole pairs and hetero-junction. It seems an efficient approach for enhanced photocatalytic performance since the greater area of contact could improve the interfacial rate of charge transfer. The phase structure of prepared WO₃ nanodots changed from the monoclinic to hexagonal phase by the addition of co-catalyst. The experimental results exhibited that carbon fiber played a tri-functional role to boost up the photocatalytic activity over MoSe₂ nanostructures. It's not only act as operative co-catalyst but could also serve as the conductive electron bridges, rather than general cocatalyst, to accumulate electrons and encourage the hydrogen generation kinetics over the WO₃ photocatalysts. More interestingly, the WO₃?1% MoSe₂?1.5% carbon fiber and WO₃?1%MoSe₂ nanocomposites demonstrated the excellent rates of hydrogen evolution 438.7 and 356.2?mmol/g.h, which were 7.6 and 6.17 times higher when compared to that of pure MoSe₂, respectively. Under the visible light excitation, the atomically junction encourages fast electron transfer from nanofibers to MoSe₂ to suppress the rapid recombination kinetics within WO₃ nanodots and extend the lifetime of WO₃ charge carrier's, thereby releasing more photogenerated electrons with higher reducing power for hydrogen evolution. The current work can contribute with new perspectives and mechanistic insight for the design and development of heterogeneous photocatalysts WO₃ based nanostructures using the combination of MoSe₂ and trifunctional carbon nanofibers for environment and energy harvesting applications.     

Separation of the Impact of Landuse/Landcover Change and Climate Change on Runoff in the Upstream Area of the Yangtze River,China

Landuse/landcover change (LULCC) and climate change (CC) impacts on streamflow in high elevated catchments are very important for sustainable management of water resources and ecological developments. In this research, a statistical technique was used in combination with the Soil and Water Assessment Tool (SWAT) to the Upstream Area of the Yangtze River (UAYR). Different performance criteria (e.g., R², NSE, and PBIAS) were used to evaluate the acceptability of the model simulation results. The model provided satisfactory results for monthly simulations in the calibration (R²; 0.80, NSE; 0.78 and PBIAS; 22.3%) and the validation period (R²; 0.89, NSE; 0.75 and PBIAS; 19.1%). Major landuse/landcover transformations from 1990 to 2005 have occurred from low grassland to medium grassland (2%) and wetlands (0.9%), bare land to medium grassland (0.2%), glaciers to wetland (16.8%), and high grassland to medium grassland (5.8%). The results show that there is an increase in average annual runoff at the Zhimenda station in UAYR by 15 mm of, which approximately 98% is caused by climate change and only 2% by landuse/landcover change. The changes evapotranspiration are larger due to climate change as compared to landuse/landcover change, particularly from August to October. Precipitation and temperature have increased during these months. On the contrary, there has been a decrease in evapotranspiration and runoff from October to March which depicts the intra-annual variations in the vegetation in the study area.

     

Quorum Sensing Involved in the Spoilage Process of the Skin and Flesh of Vacuum‐Packaged Farmed Turbot (Scophthalmus maximus) Stored at 4 °C

Fish skin has both positive and negative effects on the shelf‐life of the fish. This study aimed to investigate the spoilage process of the skin and flesh of refrigerated farmed turbot (Scophthalmus maximus) with vacuum packaging. Microbial community changes were analyzed by combining culture‐dependent and culture‐independent methods. The results indicated that the shelf‐life of vacuum‐packaged refrigerated turbot was 16 d; skin mucus was the interference factor of turbot quality. The culture‐dependent analysis demonstrated that the total viable counts and the population of H₂S‐producing bacteria, Pseudomonas spp., Enterobacteriaceae spp., and lactic acid bacteria in skin had a range of 0.45 to 1.40 log (CFU/g) higher than the microbial numbers in flesh after 16 d in storage. 16S high throughout sequencing results demonstrated that the compositions of spoilage microbes were similar in skin and flesh. Shewanella spp., followed by Carnobacterium spp., was the dominant spoilage organism at day 16. Quorum sensing (QS) signaling activity increased during the storage. Exogenous N‐butanoyl‐L‐homoserinelactone(C4‐HSL) and N‐hexanoyl‐Lhomoserine lactone (C6‐HSL) significantly accelerated the spoilage process of refrigerated turbot, while the addition of 4, 5‐Dihydroxypentane‐2, 3‐dione (DPD) prolonged the lag phase duration. Therefore, QS may be involved in the spoilage process of refrigerated turbot.     

Synthesis and characterization of a new inorganic cation-exchanger-Zr(IV) tungstomolybdate: analytical applications for metal content determination in real sample and synthetic mixture

An amorphous sample of inorganic cation-exchanger Zr(IV) tungstomolybdate was prepared by mixing varying ratios of 0.1M aqueous solution of sodium tungstate and 0.1M aqueous solution of sodium molybdate into 0.1M aqueous solution of zirconium oxychloride at pH 1. This cation-exchanger was found to have a good ion-exchange capacity (2.40 mequiv.g(-1) for Na(+)), high thermal and chemical stability. A tentative structural formula was proposed on the basis of chemical composition, FTIR and thermogravimetric analysis. Distribution coefficients (K(d)) values of metal ions in various solvent systems were determined. Some important and analytically difficult quantitative binary separations viz. Ni(II)-Pb(II), Ni(II)-Zn(II), Ni(II)-Cd(II), Mg(II)-Al(III), etc. were achieved. The practical applicability of the cation-exchanger was demonstrated in the separation of Cu(II)-Zn(II) from a synthetic mixture as well as from real samples of pharmaceutical formulation and brass alloy.