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When the timing fuze verification equipment simulates the timing fuze starting signal, the transient surge will interfere with the starting signal, resulting in inaccurate timing starting signal detection and time error. Through the Multisim process simulation of the timing starting point signal simulation module in the device, combined with the 'Miller platform' effect of the NMOSFET device, the value of the parallel capacitor CGD’ of the designed transient surge suppression circuit is studied. When CGD’ is 0.2uf, it can effectively suppress the surge, thus ensuring the accuracy of the timing starting point of the timing fuze.

Starting from a purely algebraic procedure based on the commutant of a subalgebra in the universal enveloping algebra of a given Lie algebra, the notion of algebraic Hamiltonians and the constants of the motion generating a polynomial symmetry algebra is proposed. The case of the special linear Lie algebra s l ( n ) is discussed in detail, where an explicit basis for the commutant with respect to the Cartan subalgebra is obtained, and the order of the polynomial algebra is computed. It is further shown that, with an appropriate realization of s l ( n ) , this provides an explicit connection with the generic superintegrable model on the ( n − 1 ) -dimensional sphere S n − 1 and the related Racah algebra R(n). In particular, we show explicitly how the models on the two-sphere and three-sphere and the associated symmetry algebras can be obtained from the quadratic and cubic polynomial algebras generated by the commutants defined in the enveloping algebra of s l ( 3 ) and s l ( 4 ) , respectively. The construction is performed in the classical (or Poisson-Lie) context, where the Berezin bracket replaces the commutator.

There are two distinct phases in the evolution of drift wave envelope in the presence of zonal flow. A long-lived standing wave phase, which we call the Caviton, and a short-lived traveling wave phase (in radial direction) we call the Instanton. Several abrupt phenomena observed in tokamaks, such as intermittent excitation of geodesic acoustic mode (GAM) shown in this paper, could be attributed to the sudden and fast radial motion of Instanton. The composite drift wave — zonal flow system evolves at the two well-separate scales: the micro-scale and the meso-scale. The eigenmode equation of the model defines the zero-order (micro-scale) variation; it is solved by making use of the two-dimensional (2D) weakly asymmetric ballooning theory (WABT), a theory suitable for modes localized to rational surface like drift waves, and then refined by shifted inverse power method, an iterative finite difference method. The next order is the equation of electron drift wave (EDW) envelope (containing group velocity of EDW) which is modulated by the zonal flow generated by Reynolds stress of EDW. This equation is coupled to the zonal flow equation, and numerically solved in spatiotemporal representation; the results are displayed in self-explanatory graphs. One observes a strong correlation between the Caviton-Instanton transition and the zero-crossing of radial group velocity of EDW. The calculation brings out the defining characteristics of the Instanton: it begins as a linear traveling wave right after the transition. Then, it evolves to a nonlinear stage with increasing frequency all the way to 20 kHz. The modulation to Reynolds stress in zonal flow equation brought in by the nonlinear Instanton will cause resonant excitation to GAM. The intermittency is shown due to the random phase mixing between multiple central rational surfaces in the reaction region.

A Co/Mg multilayer was proposed and optimized to work in the broad soft x-ray range of 350–770 eV. The multilayers with a d-spacing of 6.0 nm showed large interface widths of 1.95–1.07 nm which were significantly improved to 0.65–0.62 nm by using a higher Co sputtering power. Grazing incidence x-ray reflectometry, atomic force microscopy, transmission electron microscopy and x-ray diffraction measurements were used to study the multilayer structure and a more ordered polycrystalline structure was found in the multilayers deposited with higher Co power, which can explain the great improvement. The effect of Ar sputtering pressure on the layer structure was also studied. The measured soft x-ray reflectivity results indicated a high reflectivity of 18%–27.5% at 400–700 eV can be reached if a saturated number of bilayers of 50 were deposited.

With the development of smart grid and energy internet, energy storage will play an important role in maintaining the power balance and providing frequency regulation in future power system. Consequently, energy storage faces a trade-off problem between the energy market and frequency regulation market. In this work, an operation model and strategy of energy storage to provide frequency regulation is proposed. Taking lithium battery as an example of energy storage, its technical feasibility to provide frequency regulation is firstly discussed. Then, a day-ahead energy market model in the power system is constructed to calculate the revenue of lithium battery. Finally, the operation strategy of lithium battery to provide secondary frequency regulation (namely AGC) is proposed based on the model of opportunity cost. Case study is conducted on a modified IEEE 6-bus system. It shows that the reduced marginal revenue of lithium battery in the energy market increases with the growth of its declared capacity for frequency regulation. Consequently, the optimal declared frequency regulation capacity for lithium battery is the amount, at which the reduced marginal revenue in the energy market is equal to the compensation price of frequency regulation.

Bethe ansatz solution of the two-axis two-spin Hamiltonian is derived based on the Jordan-Schwinger boson realization of the SU(2) algebra. It is shown that the solution of the Bethe ansatz equations can be obtained as zeros of the related extended Heine-Stieltjes polynomials. Symmetry properties of excited levels of the system and zeros of the related extended Heine-Stieltjes polynomials are discussed. As an example of an application of the theory, the two equal spin case is studied in detail, which demonstrates that the levels in each band are symmetric with respect to the zero energy plane perpendicular to the level diagram and that excited states are always well entangled., 12 pages, 2 figures. The number of solutions and proof for their completeness, as well as some other minor changes, are provided in this revised version

The $N$-dimensional Smorodinsky-Winternitz system is a maximally superintegrable and exactly solvable model, being subject of study from different approaches. The model has been demonstrated to be multiseparable with wavefunctions given by Laguerre and Jacobi polynomials. In this paper we present the complete symmetry algebra ${\cal SW}(N)$ of the system, which it is a higher-rank quadratic one containing the recently discovered Racah algebra ${\cal R}(N)$ as subalgebra. The substructures of distinct quadratic ${\cal Q}(3)$ algebras and their related Casimirs are also studied. In this way, from the constraints on the oscillator realizations of these substructures, the energy spectrum of the $N$-dimensional Smorodinsky-Winternitz system is obtained. We show that ${\cal SW}(N)$ allows different set of substructures based on the Racah algebra ${\cal R}({ N})$ which can be applied independently to algebraically derive the spectrum of the system., Minor changes and references added

A bias-controlled spin-filter and spin memory is theoretically proposed, which consists of the junction with a single-molecule magnet sandwiched between the nonmagnetic and ferromagnetic (FM) leads. By applying different voltage pulses V write across the junction, the spin direction of the single-molecule magnet can be controlled to be parallel or anti-parallel to the magnetization of the FM lead, and the spin direction of SMM can be “read out” either by the magneto-resistance or by the spin current with another series of small voltage pulses V probe. It is shown that the polarization of the spin current is extremely high (up to 100%) and can be manipulated by the full-electric manner. This device scheme can be compatible with current technologies and has potential applications in high-density memory devices.

The correlation theory of turbulence suppression (Zhang and Mahajan 1993 Phys. Fluids B5 2000) by velocity shear was constructed by invoking the ansatz of potential vorticity conservation (PVC) that holds for relatively simple (slab) models of drift wave turbulence. It is, therefore, surprising that a detailed modern simulation of the H mode pedestal, using the gyrokinetic code GENE (Hatch et al 2018 Plasma Phys. Control. Fusion 60 084003), found ‘striking agreement’ with the predictions of the analytic model. To understand the reasons for this remarkable agreement, an extended theory that contains finite (magnetic) curvature, and which does not conserve potential vorticity, is developed and ‘solved’ by calculating an inhomogeneous Green function reflecting the fact that the new system has a potential vorticity source. It is, then, demonstrated that the effect of the broken PVC is insignificant for the normal operation parameters in tokamaks; the correction due to curvature is at the order of 2 L 0 / R , where L 0 is the scale length of the local gradient and R is the major radius. The excellent agreement between simulation and slab model 1993 theory is therefore not accidental; the latter can be applied with confidence to the tokamak pedestal.

Nanoscale Ru/C multilayers are essential reflective optics in the hard x-ray region of 7–20 keV. To understand the layer growth behavior and develop ultrathin Ru/C multilayer mirrors with periods smaller than 3.0 nm, multilayers with different periods of 6.2–1.5 nm were fabricated and studied. It is found that the average interface width started to increase obviously when the period became smaller than 2.5 nm while the surface roughness of different multilayers remained almost the same. The intrinsic stress of the multilayer gradually decreased with decreasing period and reached a very low value of −82 MPa at d = 2.3 nm. High reflectance of 54% and 65% (at E = 8.04 keV) were demonstrated for the multilayers with periods of 2.5 nm and 3.0 nm, respectively, whereas that for 1.9 nm period was significantly lower. To further analyze the layer microstructure, x-ray diffraction and transmission electron microscopy were used. The polycrystallized structure of Ru remained similar for the multilayers with period less than 2.5 nm, while a non-continuous layer growth and severe intermixing between Ru and C were observed for the multilayer with period of 1.9 nm. The increased intermixing between Ru and C was found to be the main reason for the larger interface width and lower reflectance of the multilayers with period smaller than 2.5 nm. It also indicated that the layer thickness threshold for a Ru/C multilayer growing with good layer quality is 1.0–1.2 nm.

First-principles calculations are performed to study the hole doping effect in a series of iron arsenic superconductors, such as the undoped CaFe2As2, CaFeAsF, and the hole-doped CaKFe4As4, KCa2Fe4As4F2, and KFe2As2. Charge occupations in the Fe 3d orbitals are found to show opposite variations when the filling is changed. Compared with the undoped CaFe2As2 and CaFeAsF, charges of the and orbitals decrease while those of the and d xy orbitals increase in the hole-doped materials CaKFe4As4, KCa2Fe4As4F2 and KFe2As2. By further analyzing the Pauli susceptibilities of CaFe2As2 and CaFeAsF, instability is found at the wave vector of , which is responsible for the stripe type antiferromagnetic order. In contrast, the Pauli susceptibilities of CaKFe4As4 and KCa2Fe4As4F2 at are strongly suppressed while the instabilities remain around , which may be the origin of superconductivity. Combining with the calculated orbital-resolved Pauli susceptibility, we conclude that hole doping mainly results in a decrease of charge occupations in the and orbitals, and these three orbitals play dominant roles in controlling the magnetic and superconducting properties in these iron-based superconductors.

The Keshen gas field in the Kuqa depression of the Tarim Basin with characteristics of deep buried depth, tight matrix and developed fracture, has great differences in gas well productivity within different parts of the structure, which bring difficulties to the gas field development and deployment. Based on the study of the reservoir matrix property, fracture characteristics and individual well productivity of the Keshen ultra-deep gas reservoirs, combined with reservoir geostress research, the difference between high and low efficiency wells in Keshen2 block is analysed, and the main geological factors influencing productivity are revealed. It is found that the effectiveness of reservoir fracture is a necessary condition for high production of gas well. Further study shows that there is a negative correlation between the open flow of gas well and the effective normal stress of fracture. The larger the effective normal stress of fracture is, the more difficult it is to achieve high production with reservoir reconstruction. According to study of the productivity influencing factors of the fractured tight sandstone reservoirs, some suggestions on well deployment and well perforation are given in the paper, which are beneficial to increase production and efficiency of this kind of reservoirs.

In order to solve the limitations of the “pre-set, real-time action, and regular check” working mode of traditional relay protection in offshore oil field platform grids, an online verification method of relay protection settings based on ETAP software was proposed. The real-time operating status of the current power system is obtained through the EMS system, then short-circuit calculation of various faults performed automatically under the current operation mode. The protection cooperation analysis module of ETAP software is used to realize the real-time online verification of relay protection settings. According to the matching principle of the time-current characteristic (TCC) curve, the TCC curve is graphically adjusted to meet the current protection cooperation requirements. Finally, the validity of the method is verified by engineering example simulation of a platform grid in the Bohai Sea.

Because of their unique properties, shape memory polymers (SMPs) have the potential to be used in various fields and are becoming one of the most desired shape memory materials. At present, it is generally complicated to prepare the two-way shape memory polymers (2W-SMPs) with both large reversible strain and high shape stability, which has hindered the real applications. By elaborately selecting poly(ε-caprolactone) diols (PCL-2OH) and poly(ε-caprolactone) triols (PCL-3OH) as prepolymers, a facile one-step method is employed to prepare two-way shape memory polyurethane (2W-SMPU). For this kind of SMPU, the reversible strain is found to be closely related to both the mass ratio of PCL-2OH to PCL-3OH and the initial applied stress. In this work, the smart devices of temperature-controlled lamp and gripper based on 2W-SMPU are designed and fabricated to show its two-way shape memory effect (2W-SME). The results show that its largest reversible strain can be as high as 21.3%. Moreover, it can lift up 150 times of its own weight and keep an almost constant reversible strain under a temperature-induced actuation within 50 consecutive cycles. Such 2W-SMPU materials could have lots of real applications.

The processes of electric ion extraction from plasma induced by pulse lasers are simulated by particle-in-cell (PIC) method and hybrid-PIC method. A new calculation scheme named preprocessing hybrid-PIC is presented because neither of the two methods above is omnipotent, especially under the circumstance of high initial plasma density. The new scheme provides credible results with less computational consumption than PIC method in both one- and two-dimensional simulations, except for Π-type electrode configuration. The simulation results show that the M-type performs best in all electrode configurations in both high-density and low-density plasma conditions.

Graphite / epoxy resin conductive composites were prepared by mixing and molding process, using graphite and epoxy resin as raw materials, filling carbon fiber cloth and mixing a small amount of metal powder. We investigated effects on the different ratio of graphite raw materials and the amount of carbon fiber cloth and different metal powder on the resistance and bending strength of graphite / epoxy resin conductive composites. The optimum ratio of raw materials was determined by the experiment. The results showed that the electrical and mechanical properties of the composites were good when the ratio of the two kinds of graphite was 1:1, filling two layers of carbon fiber cloth and the content of aluminum powder was 1%. The resistivity was up to 0.0800 Ω•cm, and the bending strength was up to 47.32MPa.

This paper mainly studies the synthesis of polymeric hindered amine light stabilizers by copolymerization, UV3853 (2,2,6,6-tetramethyl-4-piperidine stearate) as monomer, styrene (St The functional monomer, toluene is used as a solution, and the initiator is azobisisobutyronitrile (AIBN), and the hindered amine light stabilizer is synthesized by solution blending. The ABS composite is prepared by melt blending of the product and ABS pellets. The composite is tested for impact and tensile properties. The results show that when the addition amount of PUV-3853 is 0.1% (mass fraction), the mechanical properties of the composites are the best.

We report a ground X-ray calibration of two X-ray telescope prototypes at the PANTER X-ray Test Facility, of the Max-Planck-Institute for Extraterrestrial Physics, in Neuried, Germany. The X-ray telescope prototypes were developed by the Institute of Precision Optical Engineering (IPOE) of Tongji University, in a conical Wolter-I configuration, using thermal glass slumping technology. Prototype #1 with 3 layers and Prototype #2 with 21 layers were tested to assess the prototypes' on-axis imaging performance. The measurement of Prototype #1 indicates a Half Power Diameter (HPD) of 82" at 1.49 keV. As for Prototype #2, we performed more comprehensive measurements of on-axis angular resolution and effective area at several energies ranging from 0.5-10 keV. The HPD and effective area are 111" and 39 cm^2 at 1.49 keV, respectively, at which energy the on-axis performance of the prototypes is our greatest concern., 11 pages, 9 figures

The systems we consider are rational extensions of the harmonic oscillator, the truncated oscillator and the radial oscillator. The wavefunctions for the extended states involve exceptional Hermite polynomials for the oscillator and truncated oscillator and exceptional Laguerre polynomials for the radial oscillator. In all cases it is possible to construct ladder operators that have infinite-dimensional representations of their polynomial Heisenberg algebras and couple all levels of the systems. We construct Barut-Girardello coherent states in all cases, eigenvectors of the respective annihilation operators with complex eigenvalues. Then we calculate their physical properties to look for classical or non-classical behaviour.

The definitions of strong superadditive deficit for relative entropy coherence and monogamy deficit of measurement-dependent global quantum discord are proposed. The equivalence between them is proved, which provides a useful criterion for the validity of the strong superadditive inequality of relative entropy coherence. In addition, the strong superadditive deficit of relative entropy coherence is proved to be greater than or equal to zero under the condition that bipartite measurement-dependent global quantum discord (GQD) does not increase under the discarding of subsystems. Using the Monte Carlo method, it is shown that both the strong superadditive inequality of relative entropy coherence and the monogamy inequality of measurement-dependent GQD are established under general circumstances. The bipartite measurement-dependent GQD does not increase under the discarding of subsystems. The multipartite situation is also discussed in detail.

In this work a shunted flexible piezoelectric damping system is designed and numerically evaluated for the purpose of vibration attenuation of large deployable space cable structures. We propose a design of a tube-shaped flexible piezoelectric energy absorber consisting of multilayered PVDF sectors, which could be shunted with two types of passive electric circuits, i.e. the series resistance-inductance (LR) shunt and the series resistance-negative capacitance (NC-R) shunt. The compatible stiffness of the PVDF tube ensures an effective transformation of deformation from the vibrating cable to the energy absorber. For best performance we carried out optimization on the geometric parameters of the PVDF tube. By analysis we found that the optimal thickness of the PVDF tube is roughly 0.4 times of the inner tube radius. We optimized the shunt circuits and selected the appropriate distribution position of the damper in the flexible cable structures. The performance of the design was numerically evaluated based on three problems, namely the longitudinal vibration of a single-cable structure, the transverse vibration of a single-cable structure and the vibration of a cross-cable structure. Based on the results, we confirm the remarkable performance of the design. Being highly frequency dependent, the design with the LR shunt only works for one deformation mode at a time, e.g., bending or stretching. In contrast, the design with the NC-R shunt works for both modes as it has a much wider frequency band. The design with the LR shunt has better performance than the NC-R shunt when dealing with the stretching deformation mode only. For vibration with combined stretching and bending, however, the performance of both designs is equally good. This is because the NC-R shunt can work for both deformation modes simultaneously, and hence it shows great adaptability and application potential in vibration control of complex flexible space structures.

We obtain the exact solutions for a family of spin-boson systems. This is achieved through application of the representation theory for polynomial deformations of the $su(2)$ Lie algebra. We demonstrate that the family of Hamiltonians includes, as special cases, known physical models which are the two-site Bose-Hubbard model, the Lipkin-Meshkov-Glick model, the molecular asymmetric rigid rotor, the Tavis-Cummings model, and a two-mode generalisation of the Tavis-Cummings model., LaTex 15 pages. To appear in Nonlinearity

We propose a systematic procedure for the construction of exactly solvable kN-body systems which are natural generalisations of Calogero models. As examples, we present two new 3N-body models and determine explicit expressions for their eigenvalues and eigenfunctions.

We analyse the $n$-dimensional superintegrable Kepler-Coulomb system with non-central terms. We find a novel underlying chain structure of quadratic algebras formed by the integrals of motion. We identify the elements for each sub-structure and obtain the algebra relations satisfied by them and the corresponding Casimir operators. These quadratic sub-algebras are realized in terms of a chain of deformed oscillators with factorized structure functions. We construct the finite-dimensional unitary representations of the deformed oscillators, and give an algebraic derivation of the energy spectrum of the superintegrable system., LaTex 12 pages, 4 figures. Version to appear in J. Phys. A: Math. Theor

We have initially aligned polycrystalline EuBa2Cu3O7-δ (Eu-123) Superconductor using a magnetic force and a mechanical force simultaneously to fabricate biaxially aligned rare earth (RE) substituted Eu-123 thick films as homo-substrates for growth of epitaxial YBa2Cu3O7-δ superconductor thin films. The characterization of such Eu-123 thick films by X-ray pole figure study indicated that the polycrystalline Eu-123 grains having substantial biaxial alignment with their grain [001] axes perpendicular to the surfaces of the thick films and [010] axes parallel to the magnetic field direction in the specimen plane. We were the first to determine the biaxial alignment of Eu-123 homo-substrate by quantitative analysis of X-ray diffraction χ-circle and -circle scans of (013)/(103) reflections, demonstrating a degree of 33% alignment for both c-axis and a–b axis. The application of the biaxial alignment method to polycrystalline oxides as presented in this paper establishes a new paradigm for the processing of bulk materials.

The structural, dielectric and piezoelectric properties of xPMS–(1 − x)PZT ceramics were investigated as a function of Pb(Mn1/3Sb2/3)O3 (PMS) content by x-ray diffraction, scanning electron microscopy, and dielectric and piezoelectric spectroscopy techniques. All the Pb(Mn1/3Sb2/3)O3–PbZrO3–PbTiO3 (PMS–PZT) samples exhibit a single phase of perovskite structure with tetragonal symmetry. Dielectric studies revealed that the phase transition temperature (Tc) is suppressed with increasing PMS content. For PMS–PZT samples with 0.08 ≤ x ≤ 0.15, the maximum dielectric constant decreases as the measurement frequencies increase and the permittivity maximum temperature (Tm) is shifted towards higher temperatures as well, which indicates that dielectric relaxor behaviour was observed, while for x = 0.02 and 0.05, there is no shift in Tm, which implies normal ferroelectric behaviour. The samples with a composition of x = 0.05 exhibit excellent dielectric and piezoelectric properties (er = 1540, d33 = 360 pC N−1, Kp = 0.58, tan δ = 0.45%, Qm = 1210) and, therefore, should be ideal candidates for high-power applications, such as in piezoelectric transformers.

In this paper, we prove that all five-dimensional axisymmetric Kaluza–Klein spacetime solutions with electrostatic fields may also be those of low-energy string theory. From the class of TS-like solutions in Kaluza–Klein theory we obtain the corresponding class of solutions with electric dipoles in low-energy string theory, which are enlarged to solutions with electric charges under the SO(1, 1) transformation. We obtain the complete metric for the TS-like solution with δ = 1. Lastly, we give a discussion.

Spectroscopic diagnostic technique has been employed to investigate the characteristics of the unsteadiness of dc plasma spraying jets for two types of plasma torches. The continuous transient signal of the arc voltages and the spectral line intensities of the jets have been obtained, and their frequency characteristics have been studied by means of fast Fourier transform method. Three factors to jet fluctuation have been represented and distinguished from each other. Digital high-speed photography technique has also been introduced to investigate the fluctuation of plasma jet. Snapshots of the jet and the spectrum analysis result of arc voltage and spectral line intensity have indicated that the effect of the power supply occupies dominant proportion on the jet fluctuation for the argon plasma jet. The influence of gas flow rate on the arc restrike characteristics has been studied. Distributions of the jet temperature and number densities of nitrogen atom in the argon plasma jet region have been obtained with the distributions of line intensities of argon and nitrogen atom.

Analysis of an infinitely long train of sine-squared pulses-as a toy model-propagating in a medium exhibiting anomalous dispersion shows that although the shape of the light pulses seems to be almost preserved on a small scale, the pulses are severely distorted on a large scale. The frequency of the sine-squared pulses is doubled before they propagate a tenth of the width (FWHM) of a pulse in the medium. The analysis and a numerical calculation show that the front of a wave with a step-function envelope propagates at the speed of light, c, through a medium with two gain lines. Finally, the propagation of a Gaussian pulse-a more realistic pulse-in a medium exhibiting anomalous dispersion is studied. The distortion of the pulse in a Wang-Kuzmich-Dogariu (WKD) experiment (Wang L J, Kuzmich A and Dogariu A 2000 Nature 406 277) should be observable at a precision of +/-1 ns. If a Gaussian pulse travels in the medium for 1150 of a width (FWHM), it will collapse. 'Snapshots' of a Gaussian pulse show that the shape of the pulse in space will have more than one peak at certain times. A possible picture of light propagation in WKD-like experiments is proposed on the basis on these findings.

Dynamically engineering bandgap in semiconductors may enable a flexible design and optimization of electronics and optoelectronics. Layered black phosphorus is a 2D semiconductor with a direct bandgap and promising device characteristics. Theoretical studies indicate that the bandgap in black phosphorus can be tuned by electrical field. Here, through designing a double-gated field-effect transistor device configuration, we experimentally demonstrate that the bandgap in few-layer black phosphorus can be dynamically continually tuned by perpendicular electrical field. With an electrical displacement field of 1 V nm?1, the detailed study indicates that the bandgap can reduce around 100 meV. The finding here should be helpful on the flexible design and optimization of black phosphorus electronics and optoelectronics, and may open up some other new possible applications.

For releasing both drug and heat to selected sites, a combination of chemotherapy and photothermal therapy in one system is a more effective way to destroy cancer cells than monotherapy. Graphene oxide (GO) with high drug-loading efficiency and near-infrared (NIR) absorbance has great potential in drug delivery and photothermal therapy, but it is difficult to load drugs with high solubility. Herein, we develop a versatile drug delivery nanoplatform based on GO for integrated chemotherapy and photothermal therapy by a facile method of simultaneous reduction and surface functionalization of GO with poly(dopamine) (PDA). Due to the excellent adhesion of PDA, both low and high solubility drugs can be encapsulated in the PDA-functionalized GO nanocomposite (rGO-PDA). The fabricated nanocomposite exhibits good biocompatibility, excellent photothermal performance, high drug loading capacity, an outstanding sustained release property, and efficient endocytosis. Moreover, NIR laser irradiation facilitates the release of loaded drugs from rGO-PDA. These features make the rGO-PDA nanocomposite achieve excellent in vivo synergistic antitumor therapeutic efficacy.

Exploring exchange bias in ferromagnetic (FM)/antiferromagnetic (AFM) heterostructures is vital for both fundamental magnetism and practical application. However, in the case of conventional FM/AFM systems, the essential field cooling process above the Neel temperature of AFM materials hinders their application if the Neel temperature is far higher than room-temperature. Here, we report the effects of interfacial exchange coupling in Fe/ErFeO3 heterostructures. The magnetic-field-induced switchable exchange bias, originating from the AFM exchange coupling between Fe film and Dzyaloshinskii–Moriya-interaction-induced net moment of ErFeO3 along c axis, is successfully achieved without field cooling or in-field growth process of AFM. Different from the most previous pinning layer using a hard FM or traditional AFM, ErFeO3 pinning layer has the advantages of both the magnetic field sensitivity (~780 Oe) and ultrahigh dynamic frequency. In addition, although Fe film is polycrystalline, it exhibits a strong uniaxial magnetic anisotropy resulted from the so-called 'spin-flop-coupling effect', i.e. the magnetic coupling between Fe film and the compensated G-type AFM spins of EFO along a axis. Interestingly, the exchange bias field and asymmetric switching field offer entirely different information about the asymmetry of magnetization reversal near hard axis. The asymmetric switching field is further proved to be an effective measure to determine the weak unidirectional magnetic anisotropy for film with nearly 180° domain wall displacement. Our experimental results provide a practical method to establish room-temperature exchange bias in FM/G-type AFM without field cooling. Furthermore, the magnetic-field-induced switchable exchange-bias, the spin-flop coupling effect and the angular dependent asymmetry of magnetization reversal in the vicinity of hard axis in Fe/ErFeO3 heterostructures may provide new insights on the interfacial exchange coupling in FM/AFM systems.

In this paper, graphene oxide reinforced epoxy resin nanocomposites were successfully prepared. Compared with unmodified epoxy resin, the heat conductivity of the graphene oxide reinforced epoxy resin nanocomposites had been improved while keeping the insulation performance. The tensile strength was investigated at both room temperature (300 K) and liquid nitrogen temperature (77 K). And the fracture surfaces were examined by scanning electron microscopy (SEM). Results showed that the materials had excellent mechanical properties, which could be advantages for the applications as insulating layer in low temperature superconducting magnets.

We calculate the cross section for neutralino annihilation into the two-photon and apply the cross section to find the flux in a gamma -ray telescope such as ASTROGAM. The processes )over tilde>(0)(1) )over tilde>(0)(1) --> gamma gamma may be astrophysically significant sources of gamma -ray lines. The theoretical estimates of diffuse gamma -ray background are subject to uncertainties.

We establish the algebraic isomorphism between the Drinfeld basis of the twisted quantum affine algebra Uq(A(2)2) and the twisted Reshetihkin and Semenov-Tian-Shansky algebra by using the Gauss decomposition technique of Ding and Frenkel.

This paper presents a three-dimensional (3D) coupled-mode model using the direct-global-matrix technique as well as Fourier synthesis. This model is a full wave, two-way three-dimensional model, and is therefore capable of providing accurate acoustic field solutions. Because the problem of sound propagation excited by a point source in an ideal wedge with perfectly reflecting boundaries is one of a few three-dimensional problems with analytical solutions, the ideal wedge problem is chosen in this work to validate the presented three-dimensional model. Numerical results show that the field results by analytical solutions and those by the presented model are in excellent agreement, indicating that the presented model can serve as a benchmark model for three-dimensional sound propagation problems involving a planar two-dimensional geometry as well as a point source.

We discuss the fermion stars, the self-gravitating systems of Fermi gases, as possible gravitational lenses. It is supposed that the fermions interact with themselves and other particles only by gravity, so they are the candidates of dark matter. We calculate Einstein deflection angles, study the image configurations, and calculate the magnification factors for a number of fermion stars that range from strong relativistic configurations to nonrelativistic ones. We find that typically there are three images, one Einstein ring and one radial critical curve for both cases. Two of the images are within the Einstein ring, and the other is outside, which may be very far. All these lensing characteristics can help to identify fermion stars as potential lensing objects, thus might give direct evidence that dark fermion stars exist in the universe.

The fermion-fermion stars, i.e., the dark matter self-gravitating systems made from two kinds of fermions with different masses, are considered. We review the stability of the systems, present a comparison between the maxima of gravitational redshift for fermion stars, compact stars, Bondi stars, bonson stars and fermion-fermion stars, and then investigate rotation curves of fermion-fermion stars (two-component concentric spheres) which might be polytropic dark matter halos of galaxies. Results show that the fermion-fermion stars would give rotation curves with hat part at large radii. This presents a striking contrast with the rotation curve of a single component fermion star which has no flat parts.

We clarify the extra signs appearing in the graded quantum Yang-Baxter reflection equations, when they are written in a matrix form. We find the boundary K-matrix for the Perk-Schultz six-vertex model, thus give a general solution to the graded reflection equation associated with it.