Surface plasmons is a hotspot of research in recent years. Surface plasmons have some particular characteristics such as electric field localization and electric field enhancement. These characteristics can be used to enhance emission of light-emitting diode. Because of electric field localization, SPs has large density of states when excited. This can influence the radiation rate of exciton and improve the quantum yield The direction of radiation and the efficiency of LED can be controled by appropriate configuration. Many research groups have investigated the physical mechanism of enhance emission using SPs in recent years and get some great results. The development of enhanced emission of light-emitting diode using surface plasmons is reviewed.

As a major medical imaging technology, medical ultrasound imaging with its many advantages, such as no harm to the human body, real-time cheap and easy to use, is widely used in clinic. But the ultrasonic imaging "speckle" noise makes it difficult to distinguish between normal tissue and pathological tissue. According to the character of noise in the medical ultrasonic image, a new method of the medical ultrasonic imaging filter based on mathematics morphology and adaptive filtering is proposed after analysis of "speckle" noise and general filter ， and an experiment is made to validate. The experimental method is as follows: firstly the Rayleigh noise is imposed on the original image, and then the median filter and the adaptive median filter are used on the contaminated image. Secondly the morphological filter is used to enhance the contrast after pre-processing by the adaptive median filter on the image to retain the necessary details. Finally, the three noise filtering methods are compared from the images denoising and evaluation And the results indicate that the new method is superior to other ones

Using the modified CK's direct method, general symmetry group, Lie symmetries and corresponding vector fields of a (3+1)-dimensional nonlinear evolution equation are obtained. The relationship between new solutions and old ones of the (3+1)-dimensional nonlinear evolution equation is built by applying the results. 80me new exact solutions of the (3+1 )-dimensional nonlinear evolution equation are obtained. As for the close relationship between symmetries and conservation laws, the infinite conservation laws of the (3+1)-dimensional nonlinear evolution equation are found.

The saturation spectroscopy of the 811 nm 2P3/25p[5/2h-2p3/25s[3/2]2 line of metastable krypton atom was used to lock the frequency of a Ti:Sapphire laser. Two kinds of frequency modulation method were utilized, one using an electro-optic phase modulator, the other using an acoustic-optic frequency shifter. When the feed-back loop was closed the frequency drift was reduced to 1 MHz, while it was about 8 MHz when the loop was open. The laser can be frequency stabilized during hours-long measurements and it allows us to realize laser cooling and trapping of the different isotopes of krypton. Key words: laser technique; laser frequency locking; saturation absorption spectroscopy; frequency modulation; krypton atom; cold atom

The characteristics of the spatial beam profile of 40 GW amplified femtosecond laser pulses were studied with a homemade laser beam profile measurement system. The system was calibrated accurately and the characteristics of the spatial beam profile of femtosecond laser pulses were studied. The results indicated that the laser beam profile has better quality at lower pump current and the quality decreases as the pump current increased. The light intensity at the central area of the femtosecond laser beam may actually become weaker at high current than that at the low current. The beam quality of the pump laser had a great impact on the spatial beam profile of the femtosecond laser pulses within the multipass amplification process.

A novel method for generating highly extinctive optical pulse was proposed. The continuouswave (CW) light is modl山ted by an electrooptic phase modulator, and then modulated by a Mach-Zehnder intensity modulator in which the undesirable chirp components are sufficiently restrained. The modulated light is compressed into pulses by an equivalent chirped 且ber Bragg grating (ECFBG). The theory analysis and simulation showed that the pedestal and wings can be diminished e伍ciently in this way, and ultra-short optical pulse with extinction ratio larger than 30 dB can be generated. The experiment based on ECFBG of which gro叩delay dispersion is -380 ps/nm was demonstrated, it shows that highly extinctive optical pulse shorter than 18 ps at repetition rate of 2.5 GHz can be got when the phase modulation index is 9.

Based on the exciting technology of excimer laser used for semiconductor lithography, the charging process of pulse transformer is analyzed using the Laplace formula. It is validated that the coupling factor influences the charging time. The charging time is compressed when the coupling factor is close to 1 The discharge process of charging circuit combined with magnetic switches is introduced. A scheme for controlling the resonant charging is also proposed. The power supply designed can fulfi11 the charge process in 50μs

A scheme is proposed for realizing a controlled teleportation of an arbitrary superposetion state of an two-qubit quantum system. The resource consumption includes a prearranged six-qubit entangled quantum channel and some classical communication resources. And the quantum operations used in the teleportation process are Bell-state measurements, H-gates, single-qubit measurements and Pauli gates. It is shown that the original state can be restored by the receiver only on the condition that all the agents collaborate. If one agent does not cooperate, the original state can not be fully recovered.

Quantum key distribution protocols are already proved to be unconditionally secure, however, the complexity of the existed proving versions makes it a difficult way to further spread into the security proving of other quantum cryptography protocols. To address this problem, a new method of security analysis of QKD protocols is introduced. Based on the equivalence attack model of QKD protocols which is refered to Biham's proving, the protocol is divided into two parts: the body and the attack, then a Petri-net model of BB84 is obtained, and a security analysis is followed. The formal annlysis of QKD protocols bωed on Petri-net can improve the efficiency of security analysis. Because of its simpleness and unification, it becomes more easy to apply this method to other quantum cryptography protocols

A protocol for probabilistic cloning of a class of three-qubit Greenberger-Horne-Zeilinger (GHZ) state and its orthogonal complement state by using three maximally two states as the qua山1m channel is proposed. In this protocol, Bob (the state 町ceiver) can 町ceive the unknown state via usual teleportation process. With the assistance of Victor (the state preparer) , Alice(the state sender) can produce the perfect copies and complement copies of an unknown state. A protocol for the teleportation is given by using non-maximally entangled states as quantum channel, and the clones and complement clones of unknown state also can be obtained by Alice with assistance offered by the state preparer.

The time evolution of two coupling two-level atoms entanglement in a single-mode vacuum field is explored. The two-level atoms' reducible density matrix is obtained. The entangle ment between two two-level atoms is investigated by virtue of concurrence. The influences of the atomic dipole-dipole interaction on the entanglement of the two atoms are discussed. It is shown that the atomic dipole-dipole interaction leads to the decrease of the degrees of the entanglement and the increase of its time evolution period. In order to prepare entangled state, the influence of the atomic dipole-dipole interaction should be reduced.

By means of the quantum theory and numerical calculations method, the entanglement time evolution of the two identical two-level atoms in Bell states interacting with the two-mode odd-even entangled coherent field is investigated by using Negativity. The effects ofthe atoms initial state, mean photon numbers of field, the degree of the entanglement for the entangled coherent fields, and the coupling strength of interaction between atoms on the Negativity are discussed. The results show that the two-atom entanglement state will forever stayin the maximum entangled state when the initial state is I?ll), while the Bell state |β00) atoms appear disentanglement most of the scaled time. For the state Iβ10) ， mean photon numbers of field can be a great help, and in the state I?Ol) the co叩li吨strength of interaction between atoms plays a major role in the two-atom entanglement.

The ground state entanglement of the XY Heisenberg model of open spin-1/2 chains in one dimension was calculated and analyzed. The ground entanglement of this model was worked out by the method connecting the entanglement defined by von Neumann entropy with the ground eigenvectors. N is the total number of sites, k is the number of electrons at site spin up ， andηis the ground entanglement. The conclusions are as following. (1)ηincreases when N is same and k increases;ηdecreases when k is same and N increases. The result embodys relevancy of the system. (2)ηis always 1 when N is even and the situation is [N, N /2]. The result embodys the rigid symmetry of the numbers of electrons at site spin up and down. (3)ηis different along with the changes of the parameters of model. (4) The system has continuting and long-range phase, and the quantum phase transition of the system is order to order.

In the system of many atoms interacting with many cavity fields respectively via intensity dependent coupling, the influence of Kerr medium on process of entangled information periodic transfer between the atoms and the cavity fields is studied by means of the complete quantum theory. It is found that Kerr medium does not influence on special cases which the initial cavity fields are vacuum states or entangled states superposing of the lowest Fock states, but the phase and period of entanglement information transfer are changed obviously for the general Fock states Ink) (nk 并0) in the presence of Kerr effect. The stronger the Kerr effect, the shorter the transfer period. The speed of the entangled information transfer can be controlled by choosing different Kerr medium. In the other hand, the alteration of the transfer phase has also close relation with the photon number nk (k = 1, 2, 3, . . . ,M) in the cavity fields.

We propose a quantization scheme for a non-dissipative distributed parameter circuit. Quantum fluctuations of charge and flux in the vacuum state are investigated by adopting the canonical transformation and unitary transformation method. The results indicate that in the distributing parameter circuits, quantum fluctuations are related to both the circuit parameters and the positions and the mode of signals.

In order to obtain the interaction between of the incoherently coupled screening-photovoltaic spatial solitons, taking the two mutually incoherent optical beams with the same polarization and same wavelength as the input wave, the beam propagation equation is solved mumerically. The result shows that attraction and twine of the two solitons from each other occur when the solitons distance is suitable. If the distance is too lager or too small, the two solitons are no interaction. They are deftect simultaneously to the same side with diffusion field

To explore and validate the feasibility of in vivo real-time monitoring for brain tissue properties in stereotaxic radio frequency (RF) neurosurgery by near infrared spectrum technique, the change of absorption coefficient (μa and reduced scattering coefficient (μ's) of brain tissue is measured real-time by minimal invasive near infrared spectrum system in RF lesion of thalamotomy. The result indicates that absorption coefficient and reduced scattering coefficient increased when RF heating temperature was kept at 44℃, and μa and μ's decreased slowly when RF lesion was stopped, and the value of μa and μ's was a litter higher corresponding to the original value at the balance level. μa and μ's kept in the high level when the RF lesion temperature was set in 70℃. The μa and μ's real-time and in vivo monitoring for brain tissue by near infrared spectrum in stereotaxic RF neurosurgery is feasible.

Cu/TaN multilayer films with different modulation periods were deposited on Si substrates by magnetron sputtering method. The film microstructure and surface morphology were investigated by X-ray diffraction (XRD) measurement and atomic force microscopy (AFM) respectively. The result shows that amorphous TaN sublayer and polycrystalline Cu sublayer were obtained. With increasing modulation period L, the texture coefficient T111 of Cu(111) plane decreases. The surface roughness Rrms of Cu/TaN multilayer films with Cu top layer is less than that of Cu single layer film. The Rrms of Cu/TaN multilayer films with TaN top layer is larger than that of TaN single layer film. With increasing L, the Rrms difference between multilayer films and the single layer films decreases.

Electron transport through a mesoscopic dual rings with a stub is investigated by using quantum waveguide theory. In the case of ensuring the continuity of the wavefunction and the closing of the current, the analytic expression of the transmission coefficient is derived and the transmission properties are analysed. The results show that the transmission coefficient of electron in dual mesoscopic rings with a stub oscillates with the changing of the length of the stub, the length of the any ring, the position of the stub and the interval between the two ring. The transmission coefficient of the electron can be modulated up to 100% by modulating any parameter of the above.

Based on the NLS equation and variational method, the evolution equations for the parameters of the super-Gaussian pulse in single-mode optical fibers are deduced. Then three restricted relations between amplitude and width, frequency and chirp, width and chirp are derived. Analytical solution about the width of pulse evolves on the propagation distance is obtained. By using Runge-Kutta algorithm, the influences of the initial chirps and the degree of the pulse’s edge sharpness on the pulse width are described. The result indicates that initial chirps and the degree of the pulse’s edge sharpness have effect on amplitude, width, chirp and phase, and super-pulse has a chirp in the process of transmission, but the pulse centre equivalent frequency maintains a constant.

To meet the application requirement of real-time acquisition of observed solar data from “Kuafu A” satellite, the model, which describes the spatial relationship of position between “Kuafu A” and a single fixed station on the ground, is proposed. Then, some quantitative assessments of receiving efficiency of available domestic and oversea stations are also made. Moreover, some basic principles are illustrated for global layout for ground stations as well as a feasible optimal scheme. The results are considered as important references for real application of data communication system between spacecraft and ground of “Kuafu” project.

The source of k parameter in colorimetry of temperature measurement was introduced, the k parameter of different wavelength through experiment was analysed, and the change law by the temperature was elicited. Then the k parameter was modified by interpolation function and least square method to reduce the error of colorimetry. By comparing the two methods, it reveals that some errors are worse by interpolation function, and that it will be preferably using least square method to modify the k parameter.