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A series of novel CaLax(MoO4)1.5x+1:Eu3+ and CaLa0.6(MoO4)1.9:Eu3+,Bi3+ phosphors were synthesized through the combustion method. This study investigated the morphology, phase structure, and photoluminescence properties. All the as-prepared samples have a tetragonal structure and compatible with standard CaMoO4, belonging to the I41/a space group. The CaLa0.6(MoO4)1.9:Eu3+ (hereafter referred to as CLMO:Eu3+) phosphor possessed the strongest red emission intensity within CaLax(MoO4)1.5x+1:Eu3+ phosphors under the 393 ​nm near-ultraviolet light excited. Furthermore, the CLMO:Eu3+ phosphor showed the highest emission peak at 618 ​nm among emission peaks, which was attributed to the 5D0→7F2 transition of Eu3+. When Eu3+ was doped with 13 ​mol%, the synthesized sample had strongest red emission intensity. Moreover, Bi3+ was added into the CLMO:13%Eu3+ phosphor to improve the red color emission intensity due to the sensitization of Bi3+ to Eu3+, the maximum luminescence intensity was reached when the Bi3+ concentration was 4 ​mol%. The color purity of CLMO:13%Eu3+,4%Bi3+ phosphor reached 94.3% the emission intensity at 150 ​°C was 73.3% of that at 25 ​°C, and the activation energy of thermal quenching was 0.27 ​eV. All results indicated that the prepared phosphors could be applied as a potential red component of the w-LEDs excited by near-ultraviolet InGaN chips.

Based on the tight-binding model and the slave boson mean field approximation, we investigate the electron transport properties in a small quantum dot (QD)-ring system. Namely, a strongly correlated QD not only attaches directly to two normal metallic electrodes, but also forms a magnetic control Aharonov–Bohm quantum ring with a few noninteracting QDs. We show that the parity effect, the Kondo effect, and the multiple Fano effects coexist in our system. Moreover, the parities, defined by the odd- and even-numbered energy levels in this system, can be switched by adjusting magnetic flux phase ϕ located at the center of the quantum ring, which induces multiple controllable Fano-interference energy pathways. Therefore, the constructive and destructive multi-Fano interference transition, the Kondo and Fano resonance transition at the Fermi level, the Fano resonance and ani-resonance transition are realized in the even parity system. They can also be observed in the odd parity system when one adjusts the phase ϕ and the gate voltage V g applied to the noninteracting QDs. The multi-quantum transitions determine some interesting transport properties such as the current switch and its multi-flatsteps, the differential conductance switch at zero bias voltage and its oscillation or quantization at the low bias voltage. These results may be useful for the observation of multiple quantum effect interplays experimentally and the design of controllable QD-based device.

The structural, elastic, and thermodynamic properties of ZnGeP 2 with chalcopyrite structure are investigated using the pseudo-potentials plane wave method based on the density functional theory with the generalized gradient approximation. The lattice parameters ( a, c and u ) are directly calculated and agree well with previous experimental and theoretical results. The obtained negative formation enthalpy shows that ZnGeP 2 crystal has strong structural stability. We have also calculated the bulk modulus B and the elastic parameters ( C 11 , C 12 , C 13 , C 33 , C 44 , and C 66 ) which have not been measured yet. The accuracy and reliability of the calculated elastic constants of ZnGeP 2 crystal are discussed. In addition, the pressure and temperature dependencies of the lattice parameters, bulk modulus, Debye temperature, Gruneisen parameter, entropy, volume thermal expansion coefficient, and specific heat capacity are obtained in the ranges of 0–20 GPa and 0–1200 K using the quasi-harmonic Debye model. To our knowledge this is the first quantitative theoretical prediction of the thermodynamic properties for ZnGeP 2 compound and still awaits experimental confirmations.

The luminescence properties of green-yellow emitting (Sr1-xBax)1.95SiO4:0.05Eu2+ (0≤x≤1) phosphors were discussed in this paper. These phosphors were synthesized through the high temperature solid-state reaction technique and characterized by X-ray diffraction. The experimental results indicated that all the major phase of prepared phosphors gradually varied from α-Sr2SiO4 (x=0) phase to Ba2SiO4 (x=1) phase, and an intermediate phase between the two phases was observed at x=0.5. The excitation spectra (λem λem=524 nm) and emission spectra (λex λex=400 nm) showed a broad band character with peak located at 365 nm and range from 579 nm to 508 nm, respectively. With the increase of concentration of barium, the thermal stability of the phosphors increased first when x is less than 0.5, and then it decreased when x surpasses 0.5. In addition, luminescence intensity was enhanced with the barium concentration. Under the 400 nm NUV light excitation the (Sr1-xBax) 1.95SiO4:0.05Eu2+ phosphors have a potential application in white LED.

Crystalline alumina samples with Al2O3 content of 95.23 wt.% were prepared directly from the nepheline ore in Nanjiang county, Sichuan province of China. Four steps were involved in the experiment of alumina preparation, including calcination, dissolution, carbonation and re-calcination. Lime was used in the calcination process with the nepheline concentrates powders to generate soluble aluminates and insoluble silicates. NaOH solution was used as the mother solution in the dissolution process. CO2 was introduced into the solution to precipitate the Al (OH)3 precursor, which was then fired to obtain crystalline alumina. Among the crystalline alumina obtained three phases of crystals existed which were detected by XRD and SEM, including δ-Al2O3 as the major phase, while θ-Al2O3 and κ-Al2O3 as the minor phases. Various crystal phases of alumina could be ascribed to the purity and crystal structure of precursor, as well as the re-calcination temperature and time.

A series of red-emitting phosphors, Eu3+-doped and Eu3+ with Sm3+ co-doped Li2CaSiO4, were prepared by the combustion method. The phase composition was investigated by XRD, and photoluminescent properties were characterized by fluorescent spectrophotometer. The results show that the diffraction peaks of samples all match well with that of Li2CaSiO4 [JCPDS NO. 27-0290]. The excitation spectra consists of the broadband and the sharp lines, which are assigned to the charge transfer band (CTB) of Eu3+→O2– and the typical intra-4f transitions of the Eu3+ ions, respectively. The emission spectrum covers the characteristic f-f transitions of Eu3+, namely, 5D0→7F1 (596 nm), 5D0→7F2 (620 nm), 5D0→7F3 (657 nm) and 5D0→7F4 (705 nm). The concentration quenching occurs when Eu3+ mol fraction equals to 9%. When Eu3+and Sm3+ were co-doped, the luminous intensity of the emission spectrum was superior to the Eu3+ mono-doped, which explains the Sm3+ has a sensitization effect for Eu3+.

A red-emitting phosphor, Eu3+ activated Ca2Li2BiV3O12 was synthesized via combining combustion with solid state method and characterized by X-ray powder diffraction (XRD) and fluorescence spectrophotometer. The influence of synthesis temperature and the concentration of Eu3+ ions, on phase composition and luminescent properties of the synthesized samples was investigated systematically. The results showed that the Ca2Li2BiV3O12:Eu3+ phosphor with high phase purity and good crystallinity can be obtained by this citric acid - assisted sol combustion-solid state route at the synthesis temperature from 600°C to 700°C. The excitation spectrum of Ca2Li2BiV3O12:Eu3+ was composed of a broad band from 200 nm to 385 nm and a number of sharp small peaks extending from 390 nm to 480 nm, and the main peak was at 277 nm. The main emission peak was at 612 nm due to the electric dipole transition of 5D0 → 7F2 of Eu3+, which results in a red emitting. The sample prepared at T=680 °C, Eu3+ mol%=15 mol% has the highest emission intensity in this work.

A novel process was developed to obtain high content of ceria powder directly from bastnasite mineral. The bastnasite was roasted with NaHCO3 at 550 oC for 2 h, washed with water and dilute HCl respectively to remove impurities, and finally calcined in air. TG-DTA, XRD, XRF, SEM was used to characterize the decomposition process of bastnasite, crystalline phase, the chemical composition, and morphology of the product. The results showed that the concentration of HCl solution was the most important factor in the leaching process, and the calcining temperature of bastnasite mineral should be controlled below 600 oC. The optimal technological parameters were suggested as follows: leaching temperature at 45 oC, for 45min in 3 mol/L HCl, with the weight ratio of solid to liquid of 1:5, and the calcining of the leachate at 600 oC for 2 h. And the high content of ceria (TREO > 80wt %, Ceria/TREO > 85wt %) nanosized (20~100 nm) powder was obtained succeffully, which showed potential application in polishing materials.

In order to extensively synthesize mesoporous metal-organic frameworks (mesoMOFs), we developed a strategy to construct permanent interparticle porosity based on nanoscale metal-organic frameworks (NMOFs). Using the strategy, we have attained a series of interparticle porosity dominated mesoMOFs (IPD-mesoMOFs) from six MOF-types with MIl-100, MIL-53, HKUST-1, DUT-5, DUT-4 and MIL-101(Cr) (termed as IPD-mesoMOF-1, -2, -3, -4, -5 and -6) structure, respectively. All members of this series are not only comparable to inorganic mesoporous materials to have the tunable mesopore apertures varying from a few nanometers to over a dozen nanometers, but also superior to the inorganic counterparts to remain hierarchical porosity with higher surface area (up to 2130 m2 g−1), larger mesopore volume (the highest to 2.59 cm3 g−1) and optional micro-porosity of diverse crystalline structures. The large mesopore apertures and rich carboxyl residues on the mesopore-walls also allow the IPD-mesoMOF series to accommodate large organic and inorganic molecules, especially to immobilize the bulky natural protein, such as, hemoglobin.

High purity spherical silica powder was obtained using silica fume as the raw material in this study. The mixture acids of HF and HCl were used in the purification process to remove the impurities contained in the silica fume. The phase of the product was characterized by X-ray diffraction, indicating that the spherical silica powder was amorphous. The chemical composition of the product was investigated by X-ray fluorescence, showing the SiO2 content was 99.9096 wt%. It had been proved that the purification process could improve the dispersion of the product powder via the morphology comparison and the laser particle analyses. The experimental results showed that the parameters of the product spherical silica powder met all the standards of the electronic-grade packaging materials.

The perovskites red phosphors activated by Pr3+were prepared via the combustion method, using citric acid as a fuel and complex agent. The samples were characterized by X-ray powder diffraction and fluorescence spectrophotometry respectively. The effects of calcination temperature and doping Sr2+ion concentration on the phase compositions and luminescence properties were investigated. The CaTiO3: Pr3+can be obtained with high purity and good crystallinity by the combustion method at different calcination temperatures (750 oC, 850 oC, 900 oC, 950 oC and 1000 oC) for 1 h. The sample obtained at 900 oC exhibits the maximum emission intensity. The crystal structure of the obtained Ca1-xSrxTiO3: Pr3+(x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6) changes from perovskite to calcium strontium titanate when x ≥ 0.3. The sample exhibits the maximum red emitting when x = 0.4.

In this work, hot compression tests on columniform TC18 titanium alloy specimens were performed with a Gleeble® 3500 thermal and mechanical simulator in the temperature range of 820-875 °C and at constant strain rates of 0.01, 0.1 and 1 s−1. Relationship model of true stress versus true strain as well as peak stress versus deformation temperature were established, and microstructural micrographs of TC18 titanium alloy were analyzed. The results showed that the flow stress decreased as the deformation temperature increased or the strain rate decreased. Besides, the deformation resistance at temperature above Tβ (β transus temperature) was obviously lower than that at below Tβ. In addition, flow stresses kept almost constant when it deformed in β region where hot deformation mechanism is DRV, but significant flow softening occurred in α+β region, where deformation mechanism is mainly dominated by DRX. And in α+β region, DRX is prone to occur at a low strain rate, and it is difficult for DRX to occur at high strain rate.

We theoretically investigate the manipulation of electron-Kondo transport through a single-quantum dot (QD) two-electrode device by introducing a side-coupled graphene sheet. It is shown that with increase of coupling strength between the QD and the zero-potential graphene sheet, the anti-bias voltage capability of the QD–electrode Kondo resonance is improved obviously. This causes a high-conductance QD–electrode channel to be opened up for electron transport within a wide bias voltage range. Moreover, the conductance/current of the Kondo channel can be accurately controlled by adjusting the potential of the graphene sheet. These results may be useful for the observation of nonequilibrium Kondo effect and the design of high-conductance control device.

Under the scheme of the nonequilibrium Green’s function combined with the tight-binding approximation, we study electron transport properties in different atomic chains of an armchair-edged graphene nanoribbon (AGNR) and their manipulation using a single substitutional impurity atom. By calculation and analysis of the local bond currents between nearest atom sites in the AGNR, we find that electron transport along two armchair-edged chains is more active than that along other chains for any clean AGNR. For a metallic AGNR, interestingly, there exists a series of parallel distributed major channels for the low-energy electron transport. Further, the transport properties of these channels can be manipulated by a single substitutional impurity atom with different strength and locating position, e.g., a suitable impurity can cause a selected channel to be closed completely while others still open. However, in the high-energy regime these independent channels disappear, and a metallic AGNR becomes entirely metallic in this case. The findings here suggest that an AGNR may be used as a multi-channel plane material in the future nanoelectronic technology.

The elastic, electronic and optical properties of e-GaSe layered semiconductor have been studied from the first principles with the local density approximation (LDA). The optimized structure of GaSe has been found to be in good agreement with the experimental results. The mechanical stability of e-GaSe is confirmed by calculations of the elastic constants. The calculated band structure shows that the crystal has a direct band gap of 0.816 eV. Furthermore, the linear photon-energy-dependent dielectric functions and some optical constants such as refractive index, extinction, reflectivity and absorption coefficients have been calculated.

In this paper, dynamics of the fractional-order permanent magnet synchronous motor (FOPMSM) model is investigated. The numerical solution of the FOPMSM system is derived based on Adomian decomposition method (ADM) that is a computationally efficient and high accurate method, and its dynamical behaviors are observed by means of phase diagrams, bifurcation diagrams, Lyapunov exponent spectra (LEs), Poincaré section and chaos diagram based on spectral entropy (SE) complexity. Comparison with some reported studies, the simulation results show that it has more rich dynamical characteristics. The lowest order for the existence of chaos is 2.115 that demonstrated by 0–1 test, which is lower than that existing result (2.85). Finally, the FOPMSM system is implemented by digital signal processor (DSP), which verifies the correctness of the solution algorithm and the physical feasibility of this system. It indicates that the FOPMSM system has broad application prospect.

Based on superconducting flux qubits coupled to a superconducting resonator. We propose a scheme for implementing multi-qubit controlled-NOT (C-NOT) gates and Greenberger–Horne–Zeilinger (GHZ) state with one flux qubit simultaneously controlling on n qubits. It is shown that the resonator mode is initially in the vacuum state, a high fidelity for operation procedure can be obtained. In addition, the gate operation time is independent of the number of the qubits, and can be controlled by adjusting detuning and coupling strengths. We also analyze the experimental feasibility that the conditions of the large detuning can be achieved by adjusting frequencies of the resonator and pulses.

The effects of heat treatment on microstructure and tension property of Ni–Co film/Fe substrate systems were investigated. The deformation and fracture morphologies of Ni–Co films/Fe substrate systems were studied by in-situ scanning electron microscopy (in-situ SEM) before and after heat treatment. The results show that a Ni–Co/Fe diffusion layer appears between the film and substrate after heat treatment; the elongation of film/substrate system increases with increasing the heat treatment temperature. Both the strength and ductility of the film/substrate system are preferable when heat treatment temperature is 650 °C, meanwhile the maximum elongation is up to 46%. During tensile deformation, the deformation behaviors of Ni–Co film/Fe substrate are quite different before and after heat treatment. The samples after heat treatment went through the progress of holes' emergence, growth and extension, whereas the samples without heat treatment accompanied with no holes, just cracked instead, showing that appropriate heat treatment is helpful to improve the toughness of material, and mechanical properties.

We theoretically investigate the Kondo effect of a quantum dot embedded in a mesoscopic Aharonov–Bohm (AB) ring in the presence of the spin flip processes by means of the one-impurity Anderson Hamiltonian. Based on the slave-boson mean-field theory, we find that in this system the persistent current (PC) sensitively depends on the parity and size of the AB ring and can be tuned by the spin-flip scattering (R). In the small AB ring, the PC is suppressed due to the enhancing R weakening the Kondo resonance. On the contrary, in the large AB ring, with R increasing, the peak of PC firstly moves up to max-peak and then down. Especially, the PC phase shift of π appears suddenly with the proper value of R, implying the existence of the anomalous Kondo effect in this system. Thus this system may be a candidate for quantum switch.

The relation between the excitonic purity and the concurrence in a system of two coupled large semiconduction quantum dots mediated by a single-mode cavity field is investigated by using linear entropy theory. The results show the difference in describing two modes of excitonic entanglement between linear entropy and concurrence. The relation between nonclassical property of cavity field and the entanglement degree of excitons is also discussed. The results show that two modes of exciton can reach maximal entanglement when the cavity exhibits an antibunching effect.

We analyse the transport properties of a coupled double quantum dot (DQD) device with one of the dots (QD1) coupled to metallic leads and the other (QD2) embedded in an Aharonov–Bhom (A-B) ring by means of the slave-boson mean-field theory. It is found that in this system, the Kondo resonance and the Fano interference exist simultaneously, the enhancing Kondo effect and the increasing hopping of the QD2-Ring destroy the localized electron state in the QD2 for the QD1-leads, and accordingly, the Fano interference between the DQD-leads and the QD1-leads are suppressed. Under some conditions, the Fano interference can be quenched fully and the single Kondo resonance of the QD1-leads comes into being. Moreover, when the magnetic flux of the A-B ring is zero, the influence of the parity of the A-B ring on the transport properties is very weak, but this influence becomes more obvious with non-zero magnetic flux. Thus this model may be a candidate for future device applications.

We investigate multipartite entanglement properties in a system of driven N quantum dots coupled to a single-mode cavity field by means of state preparation fidelity and multiqubit concurrence. It is shown that the quantum collapse–revival (CR) phenomenon of the fidelity can be generated periodically when the external field is applied, and multipartite system is always in the entangled state as soon as the fidelity exhibits the CR phenomenon. We also discuss the influence of the parameters of the exciton–photon system on the CR phenomenon of the fidelity.

Ceria (CeO2) nano particles were synthesized by a new technique named "a two-stage precipitation process". The cerium(III) nitrate hexahydrate, hydrogen peroxide and ammonia were used as the raw materials. The Ce 3+ ions were oxidized to Ce 4+ ions by hydrogen peroxide, the Ce 4+ were then precipitated by ammonium hydroxide to form the precursor in the chemical reaction process. The CeO 2 nano particles were obtained by the heat treatment of the precursor for 2 hrs. at 400∼800°C after drying treatment. The phase composition and the crystal structure of the CeO2 nano particles were studied by XRD (X-ray diffraction) patterns measured at room temperature. The crystal structure of CeO 2 is cubic system. It's space group is O 5 h Fm3m. The morphogenesis of CeO2 particles is ball-like particle observed by scanning electron microscopy (SEM). The average grain size of CeO2 nano crystal was identified by transmission electron microscopy (TEM) to be about 10 nm by heating treatment for 2 hrs at 400°C. The result of ultraviolet radiation-visible light photometer measurement shows that the ultraviolet absorption capability of CeO 2 particles depends on the grain size. The CeO 2 nanoparticle prepared by the process has a better ultraviolet absorption property than that of commercial ceria microparticles. The CeO 2 nano particles exhibited photocatalytic activity for the decomposition of methyl orange under UV light irradiation.

The preparation and the photocatalytic degradation NO2 - activity of Fe3+-doped TiO2 nano-sized particles is reported in this paper. The TiO2 nano particles were prepared by sol-gel method. The various influence factors about the synthesis process of the Fe3+-doped TiO2 nano photocatalyst were controlled and investigated by XRD (X-ray diffraction), SEM (scanning electron microscopy), and TEM (transmission electron microscopy) etc.. The results show that the phase compositions, crystalline grain size, crystal structure , and photocatalytic activity of the Fe3+-doped TiO2 particles prepared by the method depend on the synthesis technology parameters such as calcination temperature, holding time, Fe3+ ions concentration etc.. The influence factors of the preparation process has been discussed. The photocatalytic decomposition of NO2 - ion into N2 and O2 using Fe3+ and Ce4+-doped TiO2 photocatalysts were investigated under UV irradiation. It was fund that Fe3+-doped TiO2 photocatalysts shows much higher photocatalytic activity than that of the Ce4+-doped TiO2 . The photocatalytic decomposition effect of NO2 - ion is related to the crystalline grain size, irradiation time, and the Fe3+ ions concentration. The Fe3+-doped TiO2 nano powders exhibited the photocatalytic degradation NO2 - activity under UV light irradiation.

We theoretically investigate the properties of the ground state of the strongly correlated T-shaped double quantum dots embedded in an Aharonov–Bohm ring in the Kondo regime by means of the one-impurity Anderson Hamiltonian. It is found that in this system, the persistent current depends sensitively on the parity and size of the ring. With the increase of interdot coupling, the persistent current is suppressed due to the enhancing Fano interference weakening the Kondo effect. Moreover, when the spin of quantum dot embedded in the Aharonov–Bohm ring is screened, the persistent current peak is not affected by interdot coupling. Thus this model may be a new candidate for detecting Kondo screening cloud.

We present a scheme to realize geometric phase-shift gate for two superconducting quantum interference device (SQUID) qubits coupled to a single-mode microwave field. The geometric phase-shift gate operation is performed in two lower flux states, and the excited state |2 would not participate in the procedure. The SQUIDs undergo no transitions during the gate operation. Thus, the docoherence due to energy spontaneous emission based on the levels of SQUIDs are suppressed. The gate is insensitive to the cavity decay throughout the operation since the cavity mode is displaced along a circle in the phase space, acquiring a phase conditional upon the two lower flux states of the SQUID qubits, and the cavity mode is still in the original vacuum state. Based on the SQUID qubits interacting with the cavity mode, our proposed approach may open promising prospects for quantum logic in SQUID-system.

We theoretically study the properties of the ground state of the parallel-coupled double quantum dots embedded in a mesoscopic ring in the Kondo regime by means of the two-impurity Anderson Hamiltonian. The Hamiltonian is solved by means of the slave-boson mean-field theory. We find that in this system, the persistent current depends sensitively on both the parity of this system and the size of the ring. In the strong coupling regime, the giant sharp current peak appears, at the same time, the parity dependence of the persistent current disappears. These imply that in the strong coupling regime, there exists giant Kondo resonance and the two dots can be coupled coherently. Thus this system might be a candidate for future device applications.

We theoretically investigate the Kondo effect of a three-terminal transport quantum dot (QD) embedded in an Aharonov–Bohm ring in the Kondo regime by means of the one-impurity Anderson Hamiltonian. The Hamiltonian is solved by means of the slave-boson mean-field theory. We find that in this system, the Kondo effect depends sensitively on the parity and size of the ring; the Kondo screening cloud can be tuned by tuning the coupling strength of the reservoir-dot. Thus this model might be a candidate for future device applications.

We study the electronic local distribution and transports in pristine armchair-edge silicene nanoribbons (ASiNRs) based on the tight-binding approximation. By calculating the local densities of states at different sites and the bond current between two adjacent sites, we show that comparing to the pristine armchair-edge graphene nanoribbons, a similar “[Formula: see text]” rule and multiple low-electron transport channels exist in the pristine [Formula: see text]-ASiNRs. However, differently, they are controllable to appear and disappear by applying an electric field perpendicular to the ribbon plane. Therefore, one can manipulate the semiconducting channels and realize the current switch “on/off,” unchanging their structures. Moreover, the results are robust against the edge-passivation and a few structural defects, which ensures their stability for the practical application in the silicene-based device.

Based on the tight-binding model and dual-probe scanning tunneling microscopy technology, we theoretically investigate the electronic structure and local property in the passivated AA-stacked bilayer armchair-edge graphene nanoribbons (AABLAGNRs). We show that they are highly sensitive to the size of the ribbons, which is evidently different from the single-layer armchair-edge graphene nanoribbons. The '3p' rule only applies to the narrow AABLGNRs. Namely, in the passivated 3p- and (3p + 1)-AABLGNRs, the narrow ribbons are semiconducting while the medium and wide ribbons are metallic. Although the passivated (3p + 2)-AABLGNRs are metallic, the '3j' rule only applies to the narrow and medium ribbons. Namely, electrons are in the semiconducting states at sites of line 3j while they are in the metallic states at other sites. This induces a series of parallel and discrete metallic channels, consisting of lines 3j - 1 and 3j - 2, for the low-energy electronic transports. In the passivated wide (3p + 2)-AABLGNRs, all electrons are in the metallic states. Additionally, the '3p' and '3j' rules are controllable to disappear and reappear by applying an external perpendicular electric field. Resultantly, an electric filed-driven current switch can be realized in the passivated narrow and medium (3p + 2)-AABLGNRs.

Motivated by recent developments in the field of 1D topological superconductors (TSCs), we investigate the phase transition properties of p-wave superconductor with 50 sites. In this paper, we first map the p-wave fermion model into the transverse [Formula: see text] model with an incommensurate modulated transverse field. We study the phase transition from TSC phase to Anderson localization phase by using imaginary time-evolving block decimation (TEBD) algorithm. By calculating the correlation function [Formula: see text], we numerically calculate the average correlation function in different p-wave pairing amplitude [Formula: see text]. By plotting the average correlation function versus the strength of incommensurate [Formula: see text] for [Formula: see text] and [Formula: see text], we identify the phase transition from TSC phase to Anderson localization phase [X. M. Cai et al., Phys. Rev. Lett. 110, 176403 (2013)]. Last but not least, we give an average measure of the entanglement of a single site with the rest of the system and von Neumann entropy of two boundary sites for the same parameters showing that the system possesses very strong entanglement at the critical point. The finite size effect and Majorana fermions are discussed in this paper.

We study the transport property for armchair-edge graphene nanoribbons (AGNRs) with an adatom coupling to a semi-infinite quantum wire. Using the nonequilibrium Green's function approach with tight-binding approximation, we demonstrate that the tunneling current through the system is sensitively dependent on both the AGNR width and adatom location. Interestingly, when the adatom locates onto a carbon atom in the 3$j$th chain from the edge of a metallic AGNR, the system shows a transmission gap accompanied by a threshold voltage in $I-V$ curve like a semiconducting AGNR. This effect may be useful in scanning tunneling microscopy experimental characterization on graphene samples., Comment: 3 pages, 4 figures

Analyses are carried out to study the effects of air velocity, particle circulating rate and fuel/air ratio on the profiles of the temperature and the heat fiux in circulating fluidized bed boilers. The particle density profile in the bed is obtained by solving a set of one-dimensional two-phase flow equations. The radiative heat transfer in the two-phase flow system is solved by using the Monte Carlo method. The following is obtained as the result. When the air velocity is increased, heat fiux to the wall is increased although the average bed temperature does not change appreciably. When the particle circulation rate is increased, the heat flux decreased although the bed temperature increased. When the fuel/air ratio is increased, both the bed temperature and the heat flux are increased.

A computer program is developed to analyze two-dimensional coupled radiative and convective heat transfer in circulating fluidized bed boiler (CFBB). Based on bulk-density distribution obtained by solving one-dimensional gas and particle two-phase flow equations, radiative heat transfer in CFBB is analyzed by using a revised Monte Carlo method. Covective heat transfer between furnace walls and gas or particles are also considered by using Martin's model. The temperature profiles of gas and particles, and the wall heat flux distributions are obtained. The results approach to the Johnsson's experimental data when horizontal mixing of particles is considered. The effects of particle diameter on the bulk density and heat transfer in CFBB are also studied.

Using the plane wave pseudopotential method within density-functional theory, we have theoretically investigated the structural, electronic, chemical bonding and optical properties of the chalcopyrite semiconductor ZnGeP2. It is found that ZnGeP2 has an indirect band gap of 1.222 eV. The covalent character of the bonds in ZnGeP2 crystal is verified by Mulliken population. By analyzing the optical properties including the dielectric function, refractive index, extinction coefficient, reflectivity spectrum and absorption coefficient, we indicate that ZnGeP2 is a promising mid-IR optical material, which is in good agreement with the available experimental results.

We performed a scanning tunneling microscopy and spectroscopy (STM/STS) study on the electronic structures of of root(3)Xroot(3)-silicene on Ag(111). We find that the coupling strength of root(3)Xroot(3)-silicene with Ag(111) substrate is variable at different regions, giving rise to notable effects in experiments. These evidences of decoupling or variable interaction of silicene with the substrate are helpful to in-depth understanding of the structure and electronic properties of silicene., Comment: 10 pages, 4 figures

In the system with superconducting quantum interference devices (SQUIDs) in cavity, the quantum logic gates operation and entanglement can be achieved by using a quantized cavity field and classical microwave pluses, via Raman transition. In this scheme, no transfer of quantum information between the SQUIDs and cavity is required, the cavity field is only virtually excited and thus the cavity decay is suppressed during the gate operation and entanglement generations. The gate operation and entanglement generations are realized by using only the two lower flux states of the SQUID system and the excited state would not be excited. Therefore, the effect of docoherence based on the levels of the SQUID system is possible to minimize.

We study the ground state property of the one-dimensional Bose—Hubbard model using an imaginary time evolving body decimation algorithm. The single-particle density matrix is numerically calculated for a Mott insulating system and a superfluid system separately. By plotting the chemical potential versus the filling n = N/L for U/J = 20 and U/J = 0.1, we identify the Mott gap for U/J = 20 in filling n = 1. Lastly, we investigate the occupation number of the Bloch state with quasimomentum for a system deep in the Mott phase and in the superfluid phase respectively. The results indicate Bose condensation in the quasimomentum space.

Optical absorption is investigated by self-consistent density matrix approach in asymmetric double quantum wells driven by an intense terahertz field and a direct current electric field polarized along the growth direction. Rich nonlinear dynamic behaviors of sideband absorption peaks are systematically studied in undoped asymmetric double quantum wells. When only in presence of a resonant terahertz field, the Autler-Townes splitting of the sideband peaks becomes pronounced with increasing the strength of the terahertz field. Quantum confined Stark effect of sideband peaks is discussed when an invariant terahertz field and a direct current electric field are simultaneously applied to the quantum well. It is shown that the sideband peaks of the 1s main absorption peak undergo a red-shift and the sideband peaks of the 2s main absorption peak undergo a blue-shift with increasing intensity of the direct current electric field. The presented results have potential applications in electro-optical devices.

We investigate the entanglement dynamics of two electron-spin qubits in the quantum-dot (QD)–microcavity system in the large-detuning limit and subjected to two different noise sources: electron-spin dephasing and relaxation. We show that when one of the two dots is prepared initially in the excited state, the created entanglement exhibits oscillatory behavior at the beginning of evolution and then completely disappears over time. For two QDs that are initially in either the Einstein–Podolsky–Rosen-Bell states or the Werner states, their entanglement evolution exhibits the same behavior in the presence of pure dephasing, but is completely different under the relaxation process. We also show that the interdot interaction induced by a single-mode cavity field does not contribute to the dynamics of entanglement for these Bell states and Werner states.

Based on the nonequilibrium Green’s function method within the tight-binding approximation scheme, through a scanning tunneling microscopy (STM) model, we study the low-energy electronic states and transport properties of carbon chains in armchair-edged graphene nanoribbons (AGNRs). We show that semiconducting AGNRs possess only semiconducting chains, while metallic ones possess not only metallic chains but also unconventional semiconducting chains located at the 3 j th ( j � 0) column from the edge (the first chain) due to the vanishing of the metallic component in the electron wavefunction. The two types of states for carbon chains in a metallic AGNR system are demonstrated by different density of states and STM tunneling currents. Moreover, a similar phenomenon is predicted in the edge region of very wide AGNRs. However, there is remarkable difference in the tunneling current between narrow and wide ribbons. (Some figures in this article are in colour only in the electronic version)

Based on the nonequilibrium Green's function with tight-binding approximation scheme, we study the scanning tunneling microscopy (STM) current from a semi-infinite quantum wire to carbon sites of a zigzag-edge graphene nanoribbon (ZGNR) via an adatom on it. We find that although the existence of local edge states, only the even order number carbon chains near the edge provide good conducting channels, and the STM image should be alternative with dark-bright fringes. This effect has not been shown in previous studies by treating a ZGNR in its entirety, and it may be useful for the STM experimental characterization on graphene samples. (C) 2011 American Institute of Physics. [doi:10.1063/1.3600788]

A novel cadmium imidazolate framework of [Cd(nim)2] (CdIF-13, nim = 2-nitroimidazolate) has been prepared and structurally characterized that demonstrates a self-penetrating 4-connected net identified with the ice XII structure of itv topology and is presented as the first metal–organic framework (MOF) with itv topology and the second metal imidazolate framework (MIF) with self-penetrating and ice-like structure.

By modulating the synthetic strategy based on changing substituents on the ligand and solvent used in the synthesis, a series of metal organic frameworks (MOFs) of two chiral binaphthol-like ligands of 4-(1H-imidaozol-1-yl)benzoic acid (HIBA) and 4-(1H-2-methylimidazol-1-yl)benzoic acid (HMIBA) with various interpenetrating topologies have been synthesized under solvothermal conditions: Zn(IBA)2 (1), Co(IBA)2 (2), Cd(IBA)2·H2O·1.7DMF (3), Cd(MIBA)2·H2O·1.3DMF (4), Co(MIBA)2·H2O·1.3DMF (5) and Cd(MIBA)2·0.5H2O·1.2DMA (6) (DMF = N,N-dimethylformamide and DMA = N,N′-dimethylacetamide). X-ray diffraction study reveals that compounds 1 and 2 crystallize in tetragonal crystal system with chiral space groupsP4122 and P4322, respectively, indicating that they are a pair of structural enantiomers, having a twofold interpenetrating (4,4)-net. Compound 3 crystallizes in orthorhombic crystal system and non-centrosymmetric space group Pca21, which can be defined as an abnormal fourfold [2 + 2] interpenetrating diamond net. The isostructural compounds 4 and 5 crystallize in tetragonal crystal system and space group P4212, representing a chiral structure and a normal mode of fourfold interpenetrating diamondoid net. Compound 6 crystallizes in non-centrosymmetric space group Aba2 and exhibits a normal mode of fourfold diamondoid interpenetrating net.

We derive the master equation of a double quantum dot charge qubit by taking into account the dissipative effects of the phonon-bath environment, and study the current noise spectrum of the double quantum dot charge qubit in terms of full counting statistics. It is found that the current is asymmetric about the current peak. The Fano factor displays an asymmetric double-peak structure, the asymmetry is due to the dissipations induced by the phonon bath. With increasing temperature T of the phonon bath, the current resonance broadens, the Fano factor peaks become smaller, and the super-Poissonian behavior vanishes.

We propose a scheme for generating the two-mode Gaussian equally squeezed state (GESS) by using the optical method and analyze the entanglement properties of this state by means of the logarithmic negativity. It is shown that such a two-mode GESS contains the same amount of entanglement as the two-mode squeezed vacuum state (TSVS). We investigate quantum nonlocality for this state by using two-mode Wigner function measurement. It is found that the operations of local squeezing and distancing can effectively enhance the degree of quantum nonlocality. We propose a quantum key distribution scheme based on the two-mode GESS, and we show that the proposed scheme is more secure against the partial interception attack strategy than one with Einstein–Podolsky–Rosen (EPR) pairs even though the transmission coefficient of the eavesdropping beam splitter is rather low.