Investigation on Photovoltaic Performance based on Matchstick-Like Cu2S–In2S3Heterostructure Nanocrystals and Polymer

In this paper, we synthesized a novel type II cuprous sulfide (Cu2S)–indium sulfide (In2S3) heterostructure nanocrystals with matchstick-like morphology in pure dodecanethiol. The photovoltaic properties of the heterostructure nanocrystals were investigated based on the blends of the nanocrystals and poly(2-methoxy-5-(2′-ethylhexoxy)-p-phenylenevinylene) (MEH-PPV). In comparison with the photovoltaic properties of the blends of Cu2S or In2S3nanocrystals alone and MEH-PPV, the power conversion efficiency of the hybrid device based on blend of Cu2S–In2S3and MEH-PPV is enhanced by ~3–5 times. This improvement is consistent with the improved exciton dissociation or separation and better charge transport abilities in type II heterostructure nanocrystals

Can Canadian investors still benefit from international diversification: a recent empirical test

This thesis examines whether Canadian investors can still benefit from international diversification in the period from January 1996 to September 2006, using monthly nominal and real returns for different asset classes of Canada, US, UK, Japan, and Hong Kong. Under Markowitz’s mean-variance analysis framework, we scrutinize the benefit of international diversification in terms of the improvement of expected return and the decrease in standard deviation. Comparing the optimization results from nominal returns and real returns, we find that while the magnitude of improving expected return and reducing risk is quite limited in this period, Canadian investors can still benefit from the international diversification by hedging domestic inflation risk, since the Canadian stock market does not represent their consumption basket well. Our empirical results also indicate that international bonds, compared with international stocks, have stronger power to improve the expected return and to reduce risk level of portfolio

Synthesis of Cu3SnS4 nanocrystals and nanosheets by using Cu31S16 as seeds

Orthorhombic Cu3SnS4 nano-cuboids and nanosheets were synthesized by using monoclinic Cu31S16 nanocrystals as seeds. Transmission electron microscopy and powder X-ray diffractometry were adopted to investigate the resultant nanocrystals and the structural transformation of monoclinic Cu31S16 to orthorhombic Cu3SnS4

A study on the microstructure of a nitrate ester plasticized polyether propellant dissolved in HCl and KOH solutions

Understanding of how the properties and performance of nitrate ester plasticized polyether (NEPE) propellants relate to microstructure is complicated by numerous components that have different characteristics. One approach to alleviating these complications is to observe a microstructure that has lost one or several components. This article examines the dissolution process, mass loss and change of the ion concentration of propellants in acid and alkali solutions. A scanning electron microscope was used to observe the dissolved residual of the propellants. The results revealed that the main constituents of NEPE propellant have different dissolving properties in solutions of HCl and KOH. By monitoring the dissolution process of NEPE propellant in HCl and KOH solutions, it was found that the microstructure of the propellant is generally compact and the polymer binder not only binds all the other components, but also protects the inner part of the propellant in solution

JSCS–4024 Original scientific paper

A study on the microstructure of a nitrate ester plasticized polyether propellant dissolved in HCl and KOH solution

Original scientific paper An SEM and EDS study of the microstructure of nitrate ester plasticized polyether propellants

Abstract: To probe the microstructures of nitrate ester plasticized polyether (NEPE) composite propellants and observe the morphology of each constitute in the propellant, the microstructure and elemental constitutes of NEPE propellants were investigated using scanning electron microscopy and energy dispersive X-ray spectroscopy. The ammonium perchlorate (AP) grains had a scraggy surface and were difficult to disperse uniformly. The compatibility between the AP grains and the polymer binder was poor, especially for large grains. The size distribution range of the AP and octogen (HMX) grains in propellants varied from several to several hundreds μm for the former while for the latter from several to several tens μm. Contrasting images before and after dissolution the propellant in trichloromethane showed that the degree of crosslinking of the polymer binder was low since non-crosslinked binder on the surface areas was easily removed by the solvent, and that the plasticizer was near the HMX grains and contributed more O to the element analysis of HMX

Mechanical Properties and Microscopic Mechanism of Coral Sand-Cement Mortar

The workability and mechanical performance of coral sand-cement mortar (coral mortar, for short) and the modification effects of mineral admixtures on the coral mortar were studied in this paper. The results showed that the strength of coral mortar was lower than that of standard mortar, but the strength of coral mortar was improved by compositing with the mineral admixture, which can be attributed to the improvement of the microstructure and interface transition area. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) were used to explore the microscopic mechanism involved in the mechanical properties, volume stability, and hydration of mortar. The analyses revealed that the internal curing effect of coral sand improved the mechanical properties of mortar and its ability to resist shrinkage. The uneven surface of coral sand formed a meshing state of close combination with the hardened cement mortar, which helped to improve the volume stability of mortar. The Ca2+ and Mg2+ ions from coral sand participated in the hydration reaction of cement, which contributed to generating more hydration products. Moreover, the microaggregate filling and pozzolanic effects of fly ash and slag improved the mechanical properties of coral mortar and resistance to chloride ion diffusion

Ultra-deep Desulfurization of Gasoline with CuW/TiO₂–GO through Photocatalytic Oxidation

Graphene oxide (GO) was co-modified with copper, tungsten, and titanium oxide. A photocatalytic reactor was used to investigate the performance of the resulting catalysts in the ultra-deep desulfurization of fluid catalytic cracking (FCC) gasoline. The resultant samples were characterized using the X-ray diffraction (XRD), scanning electron microscopy, X-ray photoelectron spectroscopy, and nitrogen adsorption–desorption techniques. XRD analysis indicated the coexistence of TiO₂, CuO, and WO₃ in the catalysts. The desulfurization rate, the refined oil yield, and the increase in the research octane number of FCC gasoline reached 100%, 99.4%, and 1.6 units, respectively, under suitable conditions of a metal content of 10.3%, a metal ratio of 0.7, a reaction temperature of 313 K, a reaction time of 1 h, a catalyst/gasoline ratio of 0.25, and an oxidant percent of 0.5%. The catalyst was active in the desulfurization reaction under ultraviolet irradiation and reused 3 times with no loss in activity