摘要：Currently,the neutron yield of Z-Pinch is lower than that of laser driven *** the neutron imaging for this facility,the signal to noise ratio(SNR)has a significant influence on the expected spatial resolution of the reconstructed fusion core,especially in the condition of low neutron *** this paper,mathematical model is purposed to describe the dependence of aperture parameters on the imaging *** investigation shows that the imaging SNR is closely related to the size of contrast boundary on the point spread *** to this,a novel non-uniform redundancy penumbra apertures array is *** addition,the imaging performances of this novel coded aperture,penumbra aperture and ring aperture are evaluated and compared by Monte Carlo *** comparison shows that this novel aperture has significant advantage compared to the penumbra aperture which is commonly used for neutron imaging with low *** encouraging results can provide reference for the optimal design of the coded aperture used in the neutron imaging for Z-pinch driven fusion with low neutron yield.

摘要：The microstructure evolution of Mg-Al-Ca alloys modified by the addition of strontium was investigated. It was found that Sr addition leads to the coarsening of α-Mg matrix. However, with the Sr content increasing from 0.1% to 0.5%, the grain size decreases from 83.9 to 65.8 μm. The addition of Sr ranging from 0.1% to 0.3% refines the Al2Ca phase. It changes the morphology of the Al2Ca phase from bone-shaped to granular or banding, and increases its volume fraction. The decrease of grain size of the α-Mg matrix is due to the increase of the effective undercooling degree of the melt and the constitutional undercooling in a diffusion layer ahead of the advancing solid/liquid interface in the alloy modified by the Sr additions. The modification mechanism of Al2Ca is attributed to the adsorption of Sr additions to the Al2Ca crystal. When the Sr content increases to 0.5%, the alloy is over-modified.

摘要：Pt/Ni catalysts modified with CeO2 nanoparticles were prepared by simple composite electrodeposition of Ni and CeO2,and spontaneous Ni partial replacement by Pt *** as-prepared CeO2-modified Pt/Ni catalysts showed enhanced catalytic performance for ethanol electro-oxidation compared with pure Pt/Ni,and acetate species were proposed to be the main products of the oxidation when using these *** content of CeO2 in the as-prepared catalysts influenced their catalytic activity,with Pt/NiCe2（obtained from an electrolyte containing 100 mg/L CeO2 nanoparticles） exhibiting higher activity and relatively better stability in ethanol *** was mainly due to the oxygen storage capacity of CeO2,the interaction between Pt and CeO2/Ni,and the relatively small contact and charge transfer *** results of this work thus suggest that electrocatalysts with low price and high activity can be rationally designed and produced by a simple route for use in direct ethanol fuel cells.

摘要：An improved understanding of fatigue behavior of a cast aluminum alloy（2-AS5U3G-Y35）in very high cycle regime is developed through the ultrasonic fatigue test in axial and torsion *** new developed torsion fatigue system is *** effects of loading condition and frequency on the very high cycle fatigue（VHCF）are *** cyclic loading in axial and torsion at 35 Hz and 20 kHz with stress ratio R=-1 is used respectively to demonstrate the effect of loading condition.S-N curves show that the fatigue failure occurs in the range of 105—1010 cycles in axial or torsion loading and the asymptote of S-N curve is inclined,but no fatigue limit exists under the torsion and axial loading *** fatigue fracture surface shows that the fatigue crack initiates from the specimen surface subjected to the cyclic torsion *** is different from the fatigue fracture characteristic in axial loading in which fatigue crack initiates from subsurface defect in very high cycle *** fatigue initiation is on the maximum shear plane,the overall crack orientation is on a typical spiral 45° to the fracture plane and it is the maximum principle stress *** clear shear strip in the torsion fatigue fracture surface shows that the torsion fracture is the shear fracture.

摘要：To study the influence of roll casting process parameters on temperature and thermal-stress fields for the AZ31 magnesium alloy sheets,three-dimensional geometric and 3D finite element models for roll casting were established based on the symmetry of roll casting by ANSYS *** method and smart-sizing algorithm were used to divide finite element mesh in ANSYS software.A series of researches on the temperature and stress distributions during solidification process with different process parameters were done by 3D finite element *** temperatures of both the liquid-solid two-phase zone and liquid phase zone were elevated with increasing pouring *** the heat transfer coefficient increasing,the two-phase region for liquid-solid becomes *** the pouring temperature increasing and the increase of casting speed,the length of two-phase zone *** optimized of process parameters（casting speed 2 m/min,pouring temperature 640 ℃ and heat transfer coefficient 15 kW/（m2·℃） with the water pouring at roller exit was used to produce magnesium alloy AZ31 sheet,and equiaxed grains with the average grain size of 50 μm were achieved after roll *** simulation results give better understanding of the temperature variation in phase transformation zone and the formation mechanism of hot cracks in plates during roll casting and help to design the optimized process parameters of roll casting for Mg alloy.

摘要：In order to investigate the influence of three key molar ratios （n（SiO2）/n（Al2O3）, n（K2O）/n（Al2O3） and n（H2O）/n（K2O））, a total of nine potassium poly-sialate-disiloxo （K-PSDS） geopolymeric cement matrices were designed according to orthogonal design principle. Subsequently, XRD, ESEM-EDXA and MAS-NMR techniques were employed to further characterize the microstructure of the most fully reacted geopolymeric cement matrix. The experimental results show that n（K2O）/n（Al2O3） has the most significant effect on compressive strength amongst the three ratios. The highest compressive strength （20.1 MPa） can be achieved when n（SiO2）/n（Al2O3）=6.5, n（K2O）/n（Al2O3）=0.8 and n（HEO）/n（K2O）=10.0. The FTIR spectra of nine PSDS geopolymeric cement matrices also indicate that geopolymeric cement matrix with the highest strength is the most fully reacted one and possesses the largest amount of geopolymeric cement products. The microscopic analysis reveals that PSDS geopolymeric cement matrix possesses structural characteristics similar to gel substances in having a wide range of Si endowments, but predominantly the framework molecular chains of Si partially replaced by 4-coordinated Al tetrahedral.

摘要：Although a great deal of studies focus on the design of flexible energy storage devices(ESDs),their mechanical behaviors under bending states are still not sufficiently investigated,and the understanding of the corresponding structural conversion therefore still lags ***,we systematically and thoroughly investigated the mechanical behaviors of flexible all-in-one ESDs under bending deformation by the finite element *** influences of thicknesses,Young’s moduli and Poisson’s ratios of electrodes and electrolyte were taken into *** and quantified results including displacement,strain energy,von Mises stress,and tensile,compressive,and interfacial shear stress are demonstrated and *** on these results,significant conclusions are drawn for the design of flexible integrated ESDs with robust mechanical *** work will provide guidance for the design of ESDs with high flexibility.

摘要：The problem of non-fragile H∞ filtering for a class of linear systems described by delta operator with circular region pole constraints is *** purpose of the paper is to design a filter such that the error filtering system not only satisfies the prescribed circular pole constraints or D-stability constraint,but also meets the prescribed H∞ norm constraint on the transfer function from the disturbance input to the estimation *** filter gain to be designed is assumed to have multiplicative gain variations.A sufficient condition for the existence of such a filter is obtained by using appropriate Lyapunov function and linear matrix inequality (LMI) technique.A numerical example is provided to demonstrate the effectiveness and less conservativenes of the proposed design.

摘要：The epidermal growth factor （EGF） has been shown to promote the proliferation of various types of cells, to maintain the physiological function of the mucosa of the digestive tract, and to promote the healing of the gastric and duodenal ulcers. It has been expressed in many types of bacteria and yeasts. In this article, a bio-reactor was constructed, namely, the human EGF （hEGF） transgenic mini-tomato. On the basis of hEGF gene sequence, a tomato codon preference hEGF gene was chemically synthesized, and it was constructed into the plant expression vector pCAMBIA2300. The transgenic tomato plants containing gene hEGF were obtained through Agrobacterium-mediated transformation. The expression product was determined by radioimmunoassay （RIA） and showed a yield of 3.48± 1.01 ng/g fresh fruits. The intragastric gavage （ig） administration of the rhEGF-containing juice of the transgenic tomato （equivalent to 24 ng rhEGF per mouse a day） for 15 days could significantly protect mice against the alcohol-induced ulceration. The ulcer index, expressed as a degree of the stomach lesion, decreased from 42.20 ±18.13 to 16.25 ±9.57.

摘要：Lorenz systems family unifying Lorenz system, Chen system and Lü system is a typical chaotic family. In this paper, we consider impulsive control Lorenz chaotic systems family with time-varying impulse intervals. By establishing an effective tool of a set of inequalities, we analyze the asymptotic stability of impulsive control Lorenz systems family and obtain some new less conservative conditions. Based on the stability analysis, we design a novel impulsive controller with time-varying impulse intervals. Illustrative examples are provided to show the feasibility and effectiveness of our method. The obtained results not only can be used to design impulsive control for Lorenz systems family, but also can be extended to other chaotic systems.