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High quality Zn0.5Co x Fe2.5 – x O4 (x = 0, 0.05, 0.1, 0.15) serial magnetic nanoparticles with single cubic structures were prepared by the modified thermal decomposition method, and Zn0.5Co x Fe2.5 – x O4/SiO2 composite magnetic nanoparticles were prepared by surface modification of SiO2. The magnetic anisotropy of the sample increases with the increase of the doping amount of Co2+. When the doping amount is 0.1, the sample shows the transition from superparamagnetism to ferrimagnetism at room temperature. In the Zn0.5Co x Fe2.5 – x O4/SiO2 serial samples, the maximum value of specific loss power (SLP) with 1974 W/gmetal can also be found at doping amount of x = 0.1. The composite nanoparticles are expected to be an excellent candidate for clinical magnetic hyperthermia.

Tumor-targeted magnetic hyperthermia has recently attracted much attention. Magnetic nanoparticles (NPs) are heat mediator nanoprobes in magnetic hyperthermia for cancer treatment. In this paper, single cubic spinel structural Zn0.3Fe2.7O4 magnetic NPs with sizes of 14 nm–20 nm were synthesized, followed by coating with SiO2 shell. The SLP value of Zn0.3Fe2.7O4/SiO2 NPs below 20 nm changes non-monotonically with the concentration of solution under the alternating current (AC) magnetic field of 430 kHz and 27 kA/m. SLP values of all Zn0.3Fe2.7O4/SiO2 NPs appear a peak value with change of solution concentration. The solution concentrations with optimal SLP value decrease with increasing magnetic core size. This work can give guidance to the better prediction and control of the magnetic hyperthermia performance of materials in clinical applications.

Magnetic properties and the magnetocaloric effect (MCE) of the RSi (R = Ce, Pr, Nd) compounds made of Misch metal (MM) are investigated. Two transitions are found at 12 K and 38 K. Field variation generated large MCE and two peaks are found in the magnetic entropy change (ΔS) curves, which correspond to the two transition temperatures. The maximum values of the magnetic entropy changes (ΔS) are found to be −5.1 J/(kg⋅K) and −9.3 J/(kg⋅K) for the field ranges of 0–2 T and 0–5 T, respectively. The large ΔS as well as ultra-low price of MM make (MM)Si a competitive magnetic refrigerant candidate for low temperature in Eriksson cycle.

This paper reports that the absorption spectra of H2O+ have been measured by tunable mid-infrared diode laserspectroscopy in the spectral range of 1100–1380 cm-1. The H2O+ ions are generated in an AC glow discharge of the gaseous mixtures of H2O/He and detected with the velocity modulation technique. Forty new lines are assigned to theν2 fundamental band of H2O+(2B1). The observed lines together with other data published previously are fitted to the standard effective Hamiltonian of an asymmetric top, yielding a set of improved rotational constants, spin-rotation constants and their quartic and sextic centrifugal distortion constants for the ν2=1 vibrational state of H2O+.

Considering the anharmonic vibrations and the interactions between electron and phonon of atoms, in this article we study the temperature dependence of Grneisen parameter, thermal expansion coefficient at low temperature and phonon relaxation time by using the theory and method of solid state physics. The influences of the anharmonic vibration of the atom on the above parameters are further discussed. The obtained results are as follows. 1) The thermal expansion coefficient of graphene is a negative value when the temperature drops below room temperature. The absolute value of the thermal expansion coefficient of graphene increases monotonically with the increase of temperature. The thermal expansion coefficient of graphene is-3.64×10-6 K-1 at room temperature. 2) The value of Grneisen parameter is zero in the harmonic approximation. If the anharmonic vibration is considered, the Grneisen parameter will increase slowly with the increase of temperature. Its value is between 1.40 and1.42 and the change is almost linear. And we find that the influence of the second anharmonic term is less than that of the first anharmonic term on Grneisen parameter. 3) The phonon relaxation time decreases with the increase of temperature. The rate changes rapidly at low temperature (T

The atomic anharmonic vibration and the electron-phonon interaction are considered, and then a physical model about the metal-based epitaxial graphene is built. Variations of the electrical conductivity and the Fermi velocity with temperature for the metal-based epitaxial graphene are given based on the solid state physics theory or method. The alkali-metal epitaxial graphene is selected as the substrate, and then the influences of substrate material, electron-phonon interaction and the anharmonic vibration on the electrical conductivity and the Fermi velocity of epitaxial graphene are discussed. Some results are shown as follows. Firstly, at zero temperature, the electrical conductivity and the Fermi velocity of the alkali-metal-base epitaxial graphene increase with the number of the atoms in substrate material increasing. Secondly, the electrical conductivity of epitaxial graphene decreases with temperature rising. Furthermore, the variation rate also decreases with temperature rising. Generally, the electrical conductivity originates mainly from electrons and phones. The electronic contribution to the electrical conductivity varies with temperature slowly, but the phone contribution to electrical conductivity varies with temperature evidently. Therefore, the contribution of phonons to electrical conductivity is much larger than that of electrons. Furthermore, the contribution increases with the number of atoms in basal elements. The phonon contribution to conductivity decreases with temperature rising, but it is unrelated to the basal elements. Thirdly, the Fermi velocity of the epitaxial graphene increases with temperature slowly. The variation of the Fermi velocity with temperature decreases with the increase of interaction between the graphene and the basal atoms. However, it increases with the number of atoms of the basal materials. The anharmonic effect causes important influences on the electrical conductivity and the Fermi velocity. Under the harmonic approximation the velocity is constant. However, the conductance increases rapidly with temperature. With considering the atomic anharmonic terms, the Fermi velocity increases with temperature. The variation of the electrical conductivity with temperature increasing becomes slower. If the temperature is higher, the anharmonic effects become more evident.

We investigate experimentally laser-induced collision energy transfer for transitions both from Eu(6s6p)8P9/2 to Sr(5s10s)1S0 and from Eu(6s6p)8- P7/2 to Sr(5s8d)1D2. Two quasi-static wings are observed in their excited function spectra. By using two dipole-dipole interactions, a spectral line from numerical calculation is consistent with the experimental line in two quasi-static wings.

Twenty-five new R-branch lines of the v2 (1−←0+) band of H3O+ are measured using diode laser velocity modulation spectroscopy between 1070 and 1230 cm−1. The H3O+ ions are produced in a high voltage ac discharge with water diluted in helium. The observed lines together with all the previously published measurements are fit to the standard vibration-rotational Hamiltonian of an oblate symmetric top, yielding a set of improved molecular constants. All the sextic centrifugal distortion constants for both 0+ and 1− states are determined precisely. The observed R(13,0) transition is shifted about -0.129 cm−1 from its calculated value, indicating that a near degeneracy exists between the (13, 0)+ and (13, 3)− ground-state rotation-inversion levels.

A single-side and one-dimensional left handed-material on the basis of periodic Ⅱ structure is designed in this paper. The Ⅱ structure of left-handed material is very simple and has some advantages, such as large bandwidth, small size and low loss. The results of simulation with the software HFSS show that for this structure in a frequency range from 8.79 GHz to 15.75 GHz, the real part and imaginary part of refraction index are less than 0 and approximately 0 respectively, and the real part of wave impedance is greater than 0, the largest loss per unit is 0.27 dB, and the relative bandwidth is 55.78%, showing that this Ⅱ periodic structure has the negative character. Based on the simulation results, this periodic Ⅱ structure is fabricated and measured with the vector network analyzer and wave guide method. The measurements are in agreement with the simulations. All these results prove that this left-handed material has some better characters than traditional meta-materials.

As an h.c.p crystal structure with only a few limited slipping planes, the AZ31 magnesium alloy exhibits a bad plasticity in the presence of external stress. Due to its low density, advanced damping capacity and high ratio strength and rigidity, the magnesium alloy has gradually become the focused and potential structural and functional metallic material in the diverse fields of aerospace, aviation and vehicle transportation, electronic products, etc. Therefore, it is of great importance to improve the process ability of conventional magnetism alloy as AZ31. In the past decades many approaches have been proposed in order to improve the plastic deformation capability. Among these, the diverse physical fields are regarded as the effective methods to improve the comprehensive mechanical properties of metallic materials due to their peculiar heat, force and quantum effects together with the advantageous characteristics of low pollution and high efficiency. In the paper, on the basis of previous researches, a high pulsed magnetic field is introduced into the tensile test to study the influences of magnetic field on the plasticity and microstructure of AZ31 magnesium alloy in order to explore a novel way to enhance the plastic deformation capability of alloy. As for the current experiment, the tensile test of AZ31 magnesium alloy is carried out under the coupling action of high pulsed magnetic field and external stress. The test results are compared with those processed without magnetic field. Several advanced detection methods are utilized to investigate the microstructure including the electron back scattered diffraction, X-ray diffraction and transmission electron microscopy, etc. Besides, the first principle is utilized to calculate the magnetic properties of main precipitates (Mg17Al12).The experimental results show that the tensile strength and elongation of the 3 T sample are increased by 2.2% and 28.7% in comparison to those of the 0 T sample. It highlights that when the high pulsed magnetic field is introduced into the plastic deformation process, the plasticity of the magnesium alloy can be improved without reducing the tensile strength of the material. The action mechanism of magnetic field is analyzed in detail and attributed to the magnetoplasticity effect. The calculation results on the basis of first principle show that the (Mg17Al12) phase is paramagnetic, which is helpful for performing the effect of magnetic field. The magnetic field enhances the flexibility of the dislocation movement and facilitates the proliferation of the dislocation. The dislocation and stress concentrating at the grain boundaries accelerate the formation of recrystallization, which is of great importance to the sub-grain generation and grain refinement that is beneficial to exhibiting the fine grain strengthening and enhancing the strength and toughness of alloy. Meanwhile, during the peculiar tensile process, the magnetic field induces the grain rotation. The newborn fine grains along the non-basal face weaken the (0001) basal texture of magnesium alloy. The characteristic of the texture structure is helpful for improving the plastic deformation capacity of AZ31 alloy. The plastic deformation under high magnetic field is regarded as an advanced way to improve the plasticities of similar nonmagnetic metallic materials such as aluminum, titanium and copper alloys and their composites.

We describe a PVK-based photorefractive polymer composite doped with disperse red 1, poly-butylacrylate and TNF. Using the two-beam coupling experiment, we investigate its photorefractive properties as well as the dynamic process of the index gratings in the sample. We observe the photorefractive effect in the absence of an applied external electric field. The two-beam coupling gain coefficient was measured to reach a value as high as 140 cm-1 in the absence of an external applied electric field and a value of 470 cm-1 at a poling dc electric field of 25V/µm.

The plasticity of material is associated closely with the movement and proliferation of dislocation. Therefore, in the deformation and plasticity theory the dislocation kinetics is an important topic. In the case of no magnetic field, the conventional dislocation kinetics normally focuses on the dislocation microstructure, nucleation and mobility, and the inherent relationship between electron spin and plasticity is seldom concerned. As a matter of fact, the electron rotation is directionless and unordered in the absence of magnetic field, so the electron behavior will not take an apparent effect on the microstructure and properties of material. Nevertheless, in the presence of magnetic field the case is different. The magnetic field will influence the electron spin and, therefore, atomic rearrangement. The dislocation behavior and plasticity will also be affected by the magnetic field, which is called the magnetoplastic effect. In this paper, on the basis of magnetoplastic effect the dislocation kinetics involving dislocation stress, mobility and others is discussed both qualitatively and quantitatively. It has rarely reported currently in the literature. The pulsed magnetic field is first utilized to process solid nanometer alumina particulates reinforced aluminum matrix composites. The experimental results demonstrate that the dislocation density increases with magnetic induction intensity increasing from zero to 3 T. The phenomenon reveals the characteristic of plastic deformation in a processed sample. The further theoretical analysis displays that the generated magnetic force is not large enough to activate the dislocation movement. The fundamental reason lies in the magnetoplastic effect, that is, the magnetic field brings about the transition of electron spin in the radical pairs between paramagnetic dislocation cores and obstacles. The radical pairs tend to be conversed from the singlet state with high bonding energy to the triplet state with low bonding energy, therefore, the prerequisite energy for dislocation to surmount the obstacles will be lowed and the depinning tendency will be apparent. In a period of dislocation movement, the rate limiting consists in the dislocation stopping at the obstacle; on the contrary, the electron excitation and atomic arrangement governed by the magnetic field take negligible time. Hence, it can be seen that the performance of magnetic field is highly efficient. The critical magnetic induction intensity is calculated to be 3 T. That is, when the intensity is lower than 3 T, the magnetoplastic effect becomes strong with the increase of magnetic induction intensity and action time; when the intensity is higher than 3 T, the effect changes gently. Under this critical magnetic induction intensity, the dislocation velocity is deduced to be on the order of 10-3 m/s. Moreover, the dislocation length will be increased by two orders of magnitude. The displacement of dislocation is proportional to the square of magnetic induction intensity and action time of magnetic field. To sum up, the magnetic field treatment has been proved to be an efficient approach to improve the plasticity of material. The prospective research will focus on the mechanical properties of alloys or composites subjected to magnetic field, together with tensile stress so as to acquire the effect of magnetic field parameters of macro plasticity of materials.

In this paper, we introduce a new type of gain guided and index antiguided (GG-IAG) large mode area (LMA) fiber structure, basic theory and its important applications in fiber laser fields. We draw a conclusion that the side pump technology is the most appropriate scheme for GG-IAG LMA fiber after comprehensively analyzing the laser output characteristics and the thermal effect of the fiber under different pump conditions. The theoretical simulations of GG-IAG fiber side pump technology and the side pump experiment process are performed by the V groove technology, which is conducible to the experiment research in relevant fields. Finally, the suggestion of how to reduce the difference between the experimental results and the theoretical results is made and its relevant reason is also discussed.

For aluminum matrix composite, the introduced particles will strengthen the matrix, but as the obstacles, the heterogeneous particles will hinder the dislocation movement, generate uneven material structure, and may become a source of stress concentration. Therefore, they are detrimental severely to the elongation and plasticity of composite. It is known that dislocations exhibit a paramagnetic behavior because they contain paramagnetic centers including localized electrons, holes, triplet excitons, ion radicals, etc. The initial radical pair of the dislocation-obstacle S (spin angular momentum) = ± 1/2 is in a singlet state, and the total spin of the radical pair is 0 and in the antiparallel spin direction, offsetting a magnetism of the radical pair. The magnetic field can change the spin direction from singlet state to triplet state. In the triplet state the electron spin is 1 and in the same spin direction. A strong bond of the dislocation-obstacle is formed only in the singlet state when the spins of the two electrons are antiparallel. So an obstacle is able to pin a dislocation only if the radical pair is in the singlet state. Under the condition of high pulsed magnetic field treatment (HPMFT) the conversion of electronic spin will be a fundamental cause of dislocation motion along a glide plane. The movement of pinned dislocations will change the material microstructure and influence the performance of material. By comparing the microstructural evolutions and the residual stresses of samples subjected to HPMFT with different values of magnetic induced density (B), the positive influence of magnetoplastic effect on the plasticity of aluminum matrix composite is investigated in this paper. The results show that the dislocation density is significantly increased when B changes from 2 T to 4 T. When B=4 T the dislocation density is enhanced by 3.1 times compared with that of the sample without HPMFT. Moreover, the residual stress is reduced apparently from 41 MPa (B=0) to -1 MPa (B=3 T). In the view of atomic scale, the high magnetic field leads to a magnetoplastic effect which contributes to the dislocation movement and promotes the dislocation depinning, thereafter, the number of movable dislocations increases up. From the viewing of the internal structure of composite, the magnetic field accelerates the releasing rate of internal stress and lowers the residual stress in material, which is beneficial to improving the plasticity of aluminum matrix composite.

The influences of atomic number and shape on Debye temperature, surface energy, surface pressure and lattice are studied by means of Me-lennard jones potential, then the influences of anharmonicity and shape on surface character are discussed. The result shows that (1) the Debye temperature and surface energy increase as atomic number increases, and that of rod nanodiamond is lower than that of cubic one. (2) The surface pressure and the variation of lattice parameter at low temperature decrease with the atom number decreasing, and the rod sample change is more apparent. The harmonic atomic surface pressure is smaller than the anharmonic one. (3) The above case is obvious when less atom number is small.

We use spectral renormalization method to solve the nonlocal nonlinear Schrdinger equation, which gives accurate waveform of nonlocal optical spatial soliton. The relation between critical power and critical beamwidth is acquired in different nonlocal conditions. We discovered that optical spatial soliton exists stably in any nonlocal degree. Comparing analytic solution with numerical solution for different response functions, we find that they are consistent only under strong nonlocal and weak nonlocal conditions. The effective range of analytic solution is also given.

In this paper, an exciton-photon model is created in an optic microcavity, and then in Bose condensation (BC), the variations of chemical potential range and number density of particles with temperature and position are studied in cases: constant width and varying width. Taking a semiconductor optic microcavity GaAs as example, the influence of temperature on BC is analyzed. The result shows that the range of chemical potential is related to dielectric function and microcavity width, while the number densities of photons and excitons and the sum of both particle numbers are related not only to them but also to temperature. The theoretical temperature of BC of GaAs is close to the experimental value. The densities of photons and excitons are almost equal, and their distributions are restricted to r=0 when BC occurs. With the reduction of temperature the number densities of both particles increase and their distributions expand, and the number of photons is more than that of excitons no matter how the width of optic microcavity changes.

In this paper, we obtain the analytical solution of the off-waist inputted complex argument Laguerre-Gaussian beams and their mean squared beam width in nonlocal nonlinear media. The propagation of the complex argument Laguerre-Gaussian beams in the nonlocal nonlinear media is investigated in detail. The examples show that the pattern shape of a (n,m) mode complex argument Laguerre-Gaussian beam varies periodically with the period Δz=πzc in strongly nonlocal nonlinear media if n≠0.But if n=0, its pattern shape remains unvaried and the beam width varies periodically during propagation. Under the off-waist incident condition, the propagation of the (0,m)mode complex argument Laguerre-Gaussian beam behaves as a breather during propagation, no matter what the power of the incident beam is. Only when the beam is input at the waist and the input power equals the critical power would the breather be reduced to a soliton.

The motion of a completely inelastic ball dropped vertically on the vibrating table will undergo a series of subharmonic bifurcations, controlled solely by the normalized vibration acceleration. It has been shown that the bifurcation diagram for the ball’s motion consists of almost equally spaced dense regions, in which the bifurcation behavior is sensitively dependent on the control parameter. The dense regions have complex interior geometrical structures. Here they are treated as fractal entities, and the fractal dimension for each of them is calculated. It is shown that the magnitude of the fractal dimension gradually increases, approaching a constant around 1.785.

Experiments have been performed to investigate the effect of subharmonic motion on size segregation in vertically vibrated granular beds. In our experimental systems, symmetric normal convection of granular particles is induced when vibration acceleration is sufficiently large, and subharmonic motion of the particles appears when vibration acceleration is above another larger critical value. Observations reveal that particle convection is the main mechanism leading to the segregation of larger intruder particles imbedded in smaller ones, the convection flux dominates the rising time of the intruder, and a distinct retardation of the segregation time is induced when the bed’s bulk motion undergoes period-doubling and period-quadrupling bifurcations. An analysis of the convection due to the effects of air is given. Then the mechanism leading to such retardation is discussed and simple expression for the segregation time is formulated. The obtained results agree well with experimental values.

A novel mutual injection phase-locking fiber laser combining technique is proposed， based on a corner-cube and a beam splitter with reflectivity of 50% at 45°， and the mutual injection phase-locking principle is introduced. Mutual injection phase-locking of two individual double clad fiber lasers is experimentally realized, steady interference stripes with high contrast ratio（about 0.57）are observed and more than 10W output power is obtained, which indicates that the power combining efficiency is 76%. Successful attempts of phase lock show that this mutual injection-locking method is a promising technology in the field of fiber laser coherent and the output power can be further scaled.

The influence of electric field and interlamellar effect on the electronic energy and wave function of spherical nanometric system is studied. Taking CdS/HgS/CdS as example， the influence of interlamellar effect， electric field and sample linear size on high-energy level Stark effect， spectral line frequency and intensity are discussed. The results show that for the spherical nanosystem CdS/HgS/CdS, the external electric field， Stark effect and the law of level effect-split-level resemble that of the hydrogen atom， but with different displacement of energy levels. The displacement of spectral lines is always proportional to the square of intensity in the electric field， and most spectral lines' frequency excursion decreased with the increase of linear sample-size， while some of the frequency excursions are on the opposite. The spectral line frequency excursion caused by interlamellar effect will decrease with the increase of linear size. Except a few spectral lines， most spectral lines will weaken with the increase of the linear size. Interlamellar effect will not change the trend of the relative intensity changing with linear size， but will make the intensities of spectral lines change. When the linear size is small， the influence of interlamellar effect on the intensity of spectral line is obvious.

Equations of excitons in columned composite systems composed of quantum dots and quantum wires have been formulated. Then the energy of excitons is solved by the perturbation theory. From the example of CdS/HgS/CdS/HgS/CdS columned composite systems composed of quantum dots and quantum wires, the electric probability distribution in this system and the dependence of energy of excitons on the size of system are studied. The results show that：(1) The energies of electrons, holes and excitions in this system all decrease as the height, h0, of quantum dots increases and the impact of the interaction of electrons holes to the energies of the ground excitons is greater than that of the excitons. (2) The probability distribution of the electrons is undulating in the ridial direction, and the probability tends to zero on the axis and near the surface and is maximal near R/2. The probability distribution of electrons is vibratory near the quantum dots in the axial direction.

A simple analysis for the behavior of a completely inelastic ball bouncing on a vertically vibrating plate has been given. Controlled by the normalized vibration acceleration, the ball undertakes a serials of subharmonic bifurcations. Several typical bifurcation processes are discussed.

The relation of Debye temperature with the interaction potential of atoms, the r elation of the mean coordination number with the shape and atomicity are deduce d. Through applying the theory of statistical physics, the variation law of the surface energy of rectangular nanocrystals along with the temperature, atomicit y and shape is obtained, and taking Ar nanocrystal as an example, the influence of shape and atomicity on the surface energy of the nanocrystal is discussed.

With the s-d commutative operation model and under the condition of the approximate single-loop of s-d commutative reciprocity for spin Green functio n, we worked out the spin excitation delay for granular films with ferromagnetic granules, and using the (α-C:H)1-xCox granular film as a n ex ample, we explored the rules that spin excitation delay changes with temperature . As a result, the process of the spin excitation delay through spin-polarized excitation is not related to temperature; however, the process through thermal e xcitation is temperature-dependent.

The(Ni79Fe21)1-xNbx(5nm)/(Ni79Fe21) (20nm)/Ta(3nm) films are prepared with the (Ni79Fe21)1-xNbx seed layers. The grain size, hyste resis loops and surface roughness of samples are measured and the variations of hysteresis loops with the Nb atomic concentration in the seed layers are analyze d. The results show the microstructure of the permalloy films grown on the seed layers is improved. The coercivity and the (B·H)m in the hysteresis loop is minimal at x=23%. The influence of seed layers on the hysteresis loops is partly duc to the different excitation energy of different seed layers, which result in different roughness of the surface of the seed layers film, hence the different microstructure of the permalloy films.

The photonic band of a set of quasi_fractal photonic crystals, which have similar structure and include idealized metal, is computed by finite-differ ence time_domain method. The result shows that there are photonic band gaps in t his kinds of quasi-fractal photonic crystals. It is found that, with increasing fractal series, the width of the photonic band gap is enlarged, the frequency of the photonic band totally trends to high frequency quickly, at the same time, the photonic band is quickly hauled to line and become a energy level.

The physical Model for the spherical HgS/CdS/HgS nanometer system and equations satistied by the electron motion are built. The energy and life span of s-electr on and the variation of the probability distribution with the width of the poten tial barrier and well are probed. Some important results indicate that the ener gy and life span of the electron increase with the increase of the potential bar rier width; electronic energy decreases with the increase of the potential well width, however the electronic life span is increased. The interaction between la yers has an important influence on the results.

We show the equivalence between the self-consistent cluster method (SCM) and the modified cluster field method (MCFM). Based on the SCM and MCFM, we propose a new method to- calculate critical points of Ising spin system, the method is demonstrated on the two-dimension square lattice.

By making use of collins model and taking Ar as an example, we calculated the thermodynamical function of liquid taking into account of the existence of vacancies, studied the critical point, Boyle temperature, Boyle Curve under the codition of motionlessness, translation and anharmonic vibration of atoms. The results obtained are close to experimental values and the results from empirical equation.

From Zou and Anderson's spinon-bolon effective Hamiltonian, for very large Coulomb repulsion U, we consider the problem of ferromagnetism on the square lattice by studying the fluctuation effect of bosons (holons).