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[en] This paper deals with the problem of energy efficiency evaluation and economic feasibility analysis of a small scale trigeneration system for combined cooling, heating and power generation (CCHP) with an available Stirling engine. Trigeneration systems have a large potential of energy saving and economical efficiency. The decisive values for energetic efficiency evaluation of such systems are the primary energy rate and comparative primary energy saving (Δq), while the economic feasibility analysis of such systems relates the avoided cost, the total annual saving and payback period. The investigation calculates and compares the energy saving and economic efficiency of trigeneration system with Stirling engine against contemporary conventional independent cooling, heating and power, showing that a CCHP system saves fuel resources and has the assurance of economic benefits
[en] Highlights: • Ni nanosheet arrays is the core and Si layer is the shell. • Ni nanosheet arrays act as a three-dimensional current collector to support Si. • Ni nanosheet arrays can improve the conductivity and stability of the electrode. • Ni/Si nanosheet arrays exhibit excellent cyclic and rate performance. - Abstract: Ni/Si core/shell nanosheet arrays are proposed to enhance the electrochemical lithium-storage properties of silicon. The arrays are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The arrays are micro-sized in height, which are constructed by interconnected Ni nanosheet as the core and Si coating layer as the shell. The electrochemical properties as anode materials of lithium ion batteries are investigated by cyclic voltammetry (CV) and galvanostatic charge-discharge tests. The arrays can achieve high reversible capacity, good cycle stability and high rate capability. It is believed that the enhanced electrochemical performance is attributed to the electrode structure, because the interconnected Ni nanosheet can act as a three-dimensional current collector, and it has the ability of improving the electrode conductivity, enlarging the electrochemical reaction interface, and suppressing the electrode pulverization.
[en] Cobalt nanosheet arrays supported silicon film is prepared and used as anode materials for lithium ion batteries. The film is fabricated using chemical bath deposition, hydrogen reduction and radio-frequency magnetron sputtering techniques. The microstructure and morphology are characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). In this composite film, the silicon layer is supported by interconnected aligned cobalt nanosheet arrays that act as the three-dimensional current collector and buffering network. The electrochemical performance as anode materials for lithium ion batteries is investigated by cyclic voltammetry (CV) and galvanostatic charge-discharge tests. The results show that the film prepared by sputtering for 1500 s exhibits high capacity, good rate capability and stable cycle ability. It is believed that the cobalt nanosheet arrays play important roles in the electrochemical performance of the silicon layer.
[en] Highlights: • The PALE method was firstly introduced to the growth of Al0.3Ga0.7As interlayer. • The AlGaAs PALE interlayer could effectively eliminate APDs and suppress the Ge inter-diffusion. • Smooth morphology (RMS: 0.43 nm) and high crystalline quality of GaAs film is achieved on 9° Ge. • The different kinds modes of Al0.3Ga0.7As PALE interlayers were analyzed-AlAs/GaAs and AlGa/AlGaAs. -- Abstract: In this paper, high quality GaAs films on Ge (0 0 1) substrates with 9° offcut toward the (1 1 1) plane were grown by metal organic chemical vapor deposition (MOCVD) through adopting the Al0.3Ga0.7As interlayers with pulsed atomic layer epitaxy (PALE) technology. The effects of Al0.3Ga0.7As PALE interlayers with different growth sequences, AlAs/GaAs PALE and AlGa/AlGaAs PALE, on the morphological, structural and optical properties of GaAs epilayers were investigated. The results showed that Al0.3Ga0.7As PALE interlayers were preferred to eliminate anti-phase domains (APDs) and suppress Ge atoms outdiffusion at the heterointerface, effectively. Additionally, AlAs/GaAs PALE, the optimized growth sequence of Al0.3Ga0.7As PALE interlayers, could obtain the smoothest surface morphology (root-mean-square (RMS) 0.43 nm) and best crystalline quality, which was attributed to the control of AsH3 exposure time ensuring fewer As vacancies acting as defect centers
[en] A series of experiments at UCSD on pure electron plasmas is described. The apparatus and methods of measurements are discussed. Results are given on various wave experiments including the dispersion of electron plasma waves, feedback growth and damping of the l = 1 diocotron wave, and the unstable growth of diocotron waves on plasmas with hollow radial profiles. The nonlinear saturation of diocotron waves, subsequent vortex merging and the decay of the resulting two-dimensional turbulence are observed. Transport processes resulting from both the single particle and collective response of the plasma to externally imposed field asymmetries have been studied. Evolution of the confined plasma to thermal equilibrium has been observed and scaling of the rate of this evolution with magnetic field has been measured. The relaxation rate of an anisotropic velocity distribution has been measured in both the usual parameter regime and the cryogenic regime where the rate is greatly reduced due to the existence of a many particle adiabatic invariant
[en] To investigate the extrahepatic collateral arteries related to hepatic artery occlusion (HAO) and to determine its benefits in the trans arterial management of liver tumors. Methods and Findings. Eleven patients (7 hepatocellular carcinomas, 3 liver metastases, and 1 with hemangioma) with HAO confirmed with digital subtraction angiography (DSA) were admitted to our hospital. Of the 11 patients, 7 were men and 4 were women, with an average age of 41.5 ± 15.5 years (range: 29 to 70 years). DSA was performed to evaluate the collateral routes to the liver. In the 11 patients with HAO, DSA showed complete occlusion of the common hepatic artery in 9 patients and the proper hepatic artery (PHA) in 2 patients. Extrahepatic collateral arteries supplying the liver were readily evident. The collateral arteries originated from the superior mesenteric artery (SMA) in 8 patients, from the gastroduodenal artery in 2 patients, and from the left gastric artery (LGA) in 1 patient. Transcatheter treatment was successfully performed via the collateral artery in all patients except the one who had hemangioma. Conclusions. DSA is an effective method for detecting collateral circulation related to HAO and may provide information to guide transcatheter management decisions.
[en] Highlights: ► We study the performance of a stress cone for a HTS cable terminal. ► An accurate model of the condenser-type termination based on ANSYS is constructed. ► We study the influence of the stress cone parameters on electric field and the potential distribution. ► We study the main reason for the partial discharges and breakdown. -- Abstract: Our research aims at improving the performance of 35 kV class stress-cone for HTS cable terminal. Firstly, the equivalent circuit model of a stress-cone is constructed for simulation. The relation between the sag voltage of each layer can be characterized by structural and material parameters, such as the stress-cone’s plate length, plate radius, insulating material thickness and dielectric constant. Secondly, the simulation based on ANSYS is developed for analyzing the electric field of stress cone of HTS cable terminal, by altering the length of step and insulation material parameter of stress cone, we get the voltage of each plate layer, horizontal electric field and vertical electric field, and the influence of stress-cone parameter on stress cone electric field is analyzed
[en] Nanoscale FeSn2 particles were prepared by chemical reduction process and solvothermal method and studied as anode materials for lithium ion batteries. The microstructure of FeSn2 was characterized by means of X-ray diffraction (XRD) and transmission electron microscopy (TEM). The FeSn2 powder prepared by chemical reduction process presented quasi-spherical morphology with aggregation, and the particle were 30-70 nm in sizes. The powder prepared by solvothermal process was nearly monodisperse nanospheres, and the particle size was 80 nm with narrow distribution. The electrochemical properties of the FeSn2 anodes were measured by galvanostatic charge-discharge tests and cyclic voltammetric analysis (CV). The FeSn2 intermetallic compound synthesized by solvothermal method showed lower initial discharge capacity and better cyclability than that prepared by chemical reduction process due to the better crystallinity. The nanoscale FeSn2 powders both delivered a high reversible discharge capacity (500 mAh g-1)
[en] Highlights: • Ni/NiO arrays prepared by hydrothermal synthesis and electrodeposition methods. • Ni/NiO nanoflake arrays show high capacity for alkaline batteries. • Introducing Ni to the NiO nanoflake is favorable for fast electron transfer. - Abstract: Construction of metal/metal oxide composite arrays is highly important for developing advanced electrochemical energy devices. In this work, we report a facile electrodeposition method to embed Ni network into hydrothermal NiO nanoflake arrays. Ni nanoparticles of 10–25 nm are intimately integrated with NiO nanoflakes of 20–30 nm forming cross-linked Ni/NiO composite arrays. The electrochemical potentials of Ni/NiO composite arrays are explored as cathode of alkaline batteries by means of galvanostatic charge/discharge tests and cyclic voltammograms (CV) in KOH solution. Compared with the unmodified NiO nanoflake arrays, the Ni/NiO composite arrays show much better electrochemical properties with higher capacity (100 mAh g−1 vs. 75 mAh g−1 at 2 A g−1), enhanced cycling life (capacity retention: 96% vs. 82%) after 3800 cycles and improved high-rate capability. The introduction of Ni nanoparticles not only improves the electrical conductivity, but also acts as anchors to fasten the active nanoflakes to achieve long-term cycles.
[en] Si/TiC nanocomposite anode was synthesized by a surface sol-gel method in combination with a following heat-treatment process. Through this process, nanosized Si was homogeneously distributed in a titanium carbide matrix. The electrochemically less active TiC working as a buffer matrix successfully prevented Si from cracking/crumbling during the charging/discharging process. The interspaces in the Si/TiC nanocomposite could offer convenient channels for Li ions to react with active Si. The Si/TiC composite exhibited a reversible charge/discharge capacity of about 1000 mAh g-1 with average discharge capacity fading of 1.8 mAh g-1 (0.18%) from 2nd to 100th cycle, indicating its excellent cyclability when used as anode materials for lithium-ion batteries