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Cu1.8S-based materials have become potential thermoelectric materials due to their rich raw material reserves, low toxicity, and excellent electrical and thermal properties. In this study, a series of Cu1.8–x Sbx S (x = 0, 0.005, 0.02, 0.03, 0.04) bulk materials is synthesized by using mechanical alloying combined with spark plasma sintering process. This preparation method can shorten the preparation cycle of materials, and effectively improve the research and development efficiency of thermoelectric (TE) materials due to its simple process. The effects of different Sb doping amounts on the structure, micromorphology, and thermoelectric transport properties of Cu1.8–x Sbx S phase are investigated. The results show that when 0 ≤ x < 0.02, the bulk samples are single-phase Cu1.8S. With the further increase of Sb doping to 0.02 ≤ x ≤ 0.04, the second phase CuSbS2 is formed when Sb content exceeds the solid solubility limit of x = 0.02 in Cu1.8S, all Cu1.8–x Sbx S bulk samples exhibit p-type conductivity characteristics. Benefitting from the synergistic phonon scattering effect by multiscale defects, such as point defects (\begin{document}${\rm{Sb}}_{{\rm{Cu}}}^{ \bullet\bullet }$\end{document}, \begin{document}$ {\rm{V}}_{\rm{S}}^{ \bullet \bullet } $\end{document}), nanopores, secondary phases (CuSbS2), and dislocations, the thermal conductivity κ declines significantly from 1.76 W·m–1·K–1 (x = 0) to 0.99 W·m–1·K–1 at 723 K for the Cu1.76Sb0.04S sample. Finally, the peak dimensionless TE figure of merit (ZT ) value of 0.37 is achieved at 723 K for Cu1.77Sb0.03S resulting from a low thermal conductivity of 1.11 W·m–1·K–1 combining an appropriate power factor of 563 μW·m–1·K–2, which is 12% higher than that (0.33) of pristine Cu1.8S. Although the Sb doped Cu1.8S-based samples have lower thermal conductivity κ, the reduced power factor cannot be offset by reducing the thermal conductivity κ, so the TE figure of merit (ZT ) value is not significantly improved. Therefore, there is still much room for improving the performance of Sb doped Cu1.8S-based thermoelectric material, and its thermoelectric performance can be further optimized through nano-second phase recombination, energy band engineering, and introducing multi-scale defects, etc. Our results suggest that the introduction of Sb into thermoelectric materials is an effective and convenient strategy to improve ZT value by reducing thermal conductivity κ.

0.7(0.1BiYbO3-0.9PbTiO3)-0.3 Pb(Mg1/3Nb2/3)O3 (0.7BYPT-0.3PMN) ternary piezoelectric ceramics were prepared by a columbite precursor method. The effects of sintering temperature on the crystalline phase, microstructure, and electrical properties of the ceramics were systematically investigated. There were two phases coexisting in the 0.7BYPT-0.3PMN ceramics sintered at 1100–1250 °C, one is the perovskite host phase with tetragonal symmetry and the other is Yb2Ti2O7 impurity phase. It was observed that, with increasing sintering temperature, the piezoelectric constant d33, dielectric constant er, planar electromechanical coupling coefficient kp, and Curie temperature TC increased initially and then decreased. An apparent structure distortion could also be observed in samples synthesized at high sintering temperature due to the severe volatilization of Pb and Bi. The optimum performances of the material were obtained for samples sintered at 1150 °C with d33 = 100 pC/N, er = 494, kp = 25.4%, and TC = 380 °C, respectively. It can be ascribed to the combined effect of a higher density, structural homogeneity with decreased tetragonality as well as a small amount of pyrochlore phase.

This study investigates the reactor core physical properties of the AP1000, which applies the MCNP4a program to model the AP1000 reactor core with the parameters and data from the DCD (19th Edition) of the AP1000 Nuclear Power Plant, which has been submitted to the NRC. The model is applied to calculate and verify the physical parameters of AP1000 core design. The results match well with the design values in the DCD of the AP1000 nuclear power plant. The design values have been calculated by the KENO-Va program, which proves the correctness of the MCNP model. The model will be improved and applied for safety review and verification analysis of AP1000 nuclear power plant in the future.

The past decade has witnessed the rapid development of (K, Na)NbO3 (KNN)-based lead-free piezoceramics. The present article reviews the current status of this system, with special emphasis on crystalline structure, piezoelectric performance and processing technologies based on the authors’ research work. In addition, the prospects and challenges are also analyzed according to the authors’ knowledge.

Nano metal-particle dispersed glasses are the attractive candidates for nonlinear optical material applications. Au/SiO2 nano-composite thin films with 3 vol% to 65 vol% Au are prepared by inductively coupled plasma sputtering. Au particles as perfect spheres with diameters between 10 nm and 30 nm are uniformly dispersed in the SiO2 matrix. Optical absorption peaks due to the surface plasmon resonance of Au particles are observed. The absorption property is enhanced with the increase of Au content, showing a maximum value in the films with 37 vol% Au. The absorption curves of the Au/SiO2 thin films with 3 vol% to 37 vol% Au accord well with the theoretical optical absorption spectra obtained from Mie resonance theory. Increasing Au content over 37 vol% results in the partial connection of Au particles, whereby the intensity of the absorption peak is weakened and ultimately replaced by the optical absorption of the bulk. The band gap decreases with Au content increasing from 3 vol% to 37 vol% but increases as Au content further increases.

采用传统固相烧结法制备了0.7BiFeO3-0.3BaTiO3-xBi2O3(0≤x≤0.05)无铅压电陶瓷, 研究了Bi补偿量x和冷却方式对其相结构、微观形貌和综合电学性能的影响。结果表明：所有样品均为菱方相(R)和伪立方相(PC)两相共存, 0≤x≤0.01样品为纯的钙钛矿结构, 且x=0.01样品的两相比例CR/CPC接近1; x>0.01样品中出现富Bi杂相Bi25FeO40。与冷却方式相比, 优化Bi补偿量更有利于提升BFBT-xBi2O3陶瓷的压电性能。随着x增大, d33先增大后减小, 在x=0.01时获得最优值。由于较小的晶粒、较合适的CR/CPC以及较大的残余应变, 水冷BFBT-0.01Bi2O3陶瓷获得了最优的压电性能(d33水冷=141 pC/N、kp=27%)和高TC=507℃。研究结果表明, BFBT基陶瓷有希望成为兼具高压电性能和高TC的无铅压电材料体系之一。

The theory of Immune Arithmetic and Agent is applied in practice. we have proposed a Decision Support System for Allocation of Education Source Based on Immune Agent. The system solves the problem that DSS can’t acclimatize itself to the dynamic environment, furthermore, it ensures that DSS can turn into a new DSS facing to question region, and can adapt itself to environmental changes to satisfy the users in solving different problems therefore it improves significantly the intelligentize of DSS. The experiments make know that it is one kind of highly effective decision model.

An HMM segmentation method based statistical layered model for an image including interest vehicle is brought forward. In statistical layered model, the interest vehicle is called foreground layer and other moving object is called background layer and shadow of moving objects is called shadow layer and is expressed by the statistical model respectively. The model parameters are estimated by the HMM-based method of video sequences. HMM- based method makes use of the spatial relativity and time relativity of video sequences to accomplish recognition of model. The experimental results show that this method can succeed segmenting the moving vehicle.

A new method of decision support system (DSS) is put forward, and the theory of immune arithmetic and agent is applied in the scopes. Based on immune agent, a decision support system of urban river water pollution control based on immune agent is proposed. The system includes apperceive agent, control agent and response agent, which solves the problem that DSS can not acclimatize itself to dynamic environment. It makes DSS face to question region, therefore it greatly improves the intelligent character of DSS, and it can adapt to the variation of environment so that the demand of the users with different problems might be better met.

Bismuth sulfide (Bi2S3) polycrystalline bulks are fabricated by spark plasma sintering (SPS) combined with a mechanical alloying (MA) process. The electrical transport properties are investigated with a special emphasis on dry-milling speed, wet-milling time and mediums in MA process. The phase structure, the microstructure, and the electrical/thermal transport properties for the bulk samples are measured. The results suggest that the second Bi2O3 phase is formed because of the micro-oxidation when the wet medium is fixed to absolute ethyl alcohol, which refines the grain sizes and affects electrical transport properties of the bulk samples. Prolonging the wet-milling time in absolute ethyl alcohol causes the increase of resistivity and the decrease of the power factor. The electrical transport properties degrade due to the porous microstructure in bulk samples even without oxidization as the acetone is used as a milling medium. The largest ZT value 0.25 is obtained at 573 K for the samples dry-milled under 425 r/min for 15 h without wet-milling, which is the highest value in the reported values so far.

Ni and Se co-doped skutterudite compounds Co 1- x Ni x Sb 3- y Se y with fine grains were fabricated by combining mechanical alloying and spark plasma sintering. The coupling effect between grain boundary scattering and point defect scattering on the thermoelectric transport properties was focused.The enhanced power factor by co_doping is twice that of the sample without Ni and achieved a maximum value of 1750μWm -1 K -2 at 450℃ for x =0.1. Due to the coupling scattering effect, the lattice thermal conductivity at room temperature decreased to 1.67Wm -1 K -1 , which approach the reported minimum of 1.60Wm -1 K -1 , whareas the improved ZT value reached 0.53 at 450℃ for the Co 0.9 Ni 0.1 Sb 2.85 Se 0.15 . A suggested model shows that the decreased thermal conductivity is duc to the coupling effect between grain boundary scattering and point defect scattering, The calculated values are in good agreement with experimental results. The simulated results also suggest that the lattice thermal conductivity could be further decreased to 0.8Wm -1 K -1 when the grain size was reduced to 50nm.

CoSb3 powders were synthesized by mechanical alloying (MA) with Co and Sb powders as starting materials. The influence of milling speed and duration on the solid reaction were systematically studied. The XRD results indicated that the CoSb3 phase increased with prolonged MA-time, but extensive MA resulted in the appearance of CoSb2 and the decomposition of CoSb3 to CoSb2 and amorphous Sb at a constant MA-speed. Increasing the MA-speed can shorten the incubation time of the reaction, but doesn't influence the MA solid reactions themselves. For MA processes that give a specific state of alloying, the MA-speed and the MA-time should satisfy the relationship: ω3.8t=C(constant), which expresses the relationship of equivalency between MA-speed and MA-time, indicating that the supplied energy is being accumulated during MA. The MA mechanism concerning the formation of CoSb3 has been discussed on the basis of MA from a viewpoint of non-equilbrium thermodynamics.

Au/SiO2 nano-composite multilayer thin films were prepared by magnetr on plasma sputtering. The microstructure, morphology and optical properties were investigated using transmission electron microscopy and absorption spectra. The Au particles dispersed in the SiO2 matrix of one single Au layer gre w with increasing deposition time in the initial time interval of less than 10s. No obvious change in the size of Au particles was observed in the films deposit ed for more than 10s, however, the shape of Au particles changed. The optical ab sorption peaks due to the surface plasma resonance appeared at a wavelength of 5 40—560nm for ［Au(t1)SiO2(600)］×5 thin films . The intensity of the absorption peak increased with increasing deposition time . Influence of the Au particle shape on the position and intensity of plasma res onance absorption peak was also discussed. The optical absorption spectra of Au/ SiO2 thin films are well in agreement with the theoretical optical ab sorption spectra calculated from reformed Maxwell-Garnett effective medium theor y.

Au/SiO2 nano-composite multilayer thin films were prepared by magnetron plasma sputtering. The effect of microstructure on the absorption spectra of films of the same thickness but under different deposition conditions, and films deposited under the same conditions but having different thicknesses was investigated. The results show that the optical absorption peaks appeared at 560 nm for the Au/SiO2 nano-composite multilayer films, the intensity of the absorption peak increased with increasing Au content and thickness of films. No nano-multilayer structure and absorption peak was observed when Au particle connected together due to high Au content. The optical absorption spectra of Au/SiO2 multilayer thin films well agree with the theoretical optical absorption spectra calculated from modified Maxwell-Garnett effective medium theory.