In recent years, the rapid development of atom interference technique provides a new way for rotation precision measurement and the related applications. The sensitivitiy of atom interferometer is higher than that of the traditional optical gyroscopes. It is a new generation of inertial measurement instrument, and it has great application prospects. The basic principle, main performance and technical characteristics of Raman-type atom interferometry gyroscopes are introduced. The latest research progress in the field of Raman interference type cold atom gyroscope is presented. The research status and development prospects are analyzed.

Ion-induced nucleation is a very important nucleation type, and it is also one of the main sources of new particles in atmosphere. It has a significant impact on the formation of new particles in atmosphere. By simulation of photoelectron and infrared spectroscopy of hydrated oxalate, it’s found that number of water molecules can affect the stability of cluster molecules. With respect to C2O2-4 (H2O)3 cluster, the addition of the fourth water molecule can effectively stabilize the two electrons with Coulomb repulsion on the oxalate molecule. The interaction between water molecules in oxalate hydrate clusters is weaker than that between water and oxalate molecule in hydrated. Simulation of infrared spectroscopy shows that the number of water molecules has less effect on the nuclear structure of oxalate.

Aiming at the related problems of character feature extraction in the original handwritten Chinese characters recognition system, effective features of similar words are learned combining with convolution neural network intelligent, and a new optical image recognition system for handwritten Chinese characters is designed. Efficient training to models is carried out with the rich data resources in handwritten cloud platform. The specific similar subsets are formed according to frequency statistics, and the recognition rates are optimized effectively. Experimental results show that the proposed method can significantly improve recognition rate compared with the support vector machine (SVM) and nearest neighbor classifier method.

The classical symmetries are expanded by calculating the potential symmetries of nonlinear telegraph-type (NTT) and Burgers equations, and a series of new exact solutions of Burgers equation are obtained. The classical symmetries and potential symmetries of NTT and Burgers equations are determined based on differential characteristic set algorithm, and one-parameter Lie transformation group of two potential symmetries to Burgers equation is calculated. The invariant solutions of Burgers equation are constructed by using generalized simple equation method, and these solutions are expressed by hyperbolic functions, trigonometric functions and rational functions with any two parameters respectively. New exact solutions are obtained by acting Lie transformation group (14) of potential symmetry on Burgers equation, and these solutions can’t be obtained by the classical symmetry of the equation.

The fiber-pigtailed LiNbO3 electro-optical modulator with Mach-Zehnder(M-Z) structure is used as the active Q switching element. The all fiber active Q-switched laser at 1550 nm is realized with 974 nm diode laser as pump source and Yb-doped fiber with 110 dB/m peak absorption coefficient as gain medium. The periodic modulation of cavity loss is carried out with electro-optic intensity modulator. Q-switching action is realized and the stable Q-switched pulse output is obtained. The change laws of pulse width and peak power are investigated by changing pump power and modulation frequency. The stable output pulse can be obtained when the modulation frequency is adjusted from 50 Hz to 88 kHz. The most narrow pulse width of 246 ns and peak power about 5 W are obtained when the modulation frequency is 1 kHz.

A broadband erbium-doped passively mode-locked fiber laser is proposed and demonstrated. It lays the foundation for optical frequency comb and generation of fiber femtosecond pulse. Based on the mode-locked mechanism of nonlinear polarization rotation, the laser combines C-band and L-band erbium-doped fiber reasonably in large normal dispersion region to ensure that the laser has a gain spectrum coverage of C+L band. When the pump power reaches 350 mW, the pulses operate stably with fundamental frequency of 4.32 MHz, 3 dB bandwidth is 60 nm and 20 dB spectrum covers from 1522 nm to 1630 nm. The full coverage of gain bandwidth is achieved. The method can effectively avoid nonlinear phase noise of spectrum components by using gain splicing to broaden spectrum, and it is conducive to further compress pulse.

Universal quantum computation overcoming influnce of bit-flip error is realized by suppressing collective decoherence with decoherence-free subspace method. The scheme is based on cavity QED system. A logical bit is encoded by two adjacent atoms trapped in a cavity, and a four-dimensional decoherence-free subspace is constructed to suppress the collective bit reversal error. By adjusting the coupling between the external optical field and cavity, two noncommutative single-qubit operations and a controlled phase gate are implemented in decoherence-free subspace. Universal quantum computation overcoming the collective bit reversal error is realized.

By solving Milburn equation, the dynamical properties of quantum entanglement and average fidelity in Heisenberg spin chain model with nonlinear interaction are investigated. The effects of nonlinear interaction and different initial states on the quantum entanglement and average fidelity decoherence are discussed. Results show that the conditions for system in ferromagnetic or antiferromagnetic are different on change of quantum entanglement versus nonlinear interaction. When the interaction is in ferromagnetic state, the entanglement change is more obvious than that of the antiferromagnetic entanglement. Different initial states correspond to different average fidelity. The choice of initial state can affect the quantum communication characteristics of the system.

In order to reduce the interference among multiple users, a new system (multi-bit, multiple access differential chaos shift keying, MA-DCSK) of chaotic multiple access communication is proposed, and the multi-user detection algorithm is designed. Through simulation, the bit error rate (BER) of multi-bit MA-DCSK system is compared with the variable delay MA-DCSK (VDMA-DCSK), and the result proves that the new system has lower BER. By making use of the parallelism computation characteristic of quantum, the Grover quantum algorithm is used to solve the computational complexity of the multi-user detection algorithm, and it can reduce the computational complexity from N to N. The simulation result shows Grover quantum algorithm can effectively reduce the computational complexity without affecting the system performance at the same time.

In order to achieve the superior filtering characteristics of one-dimensional photonic crystal, the gradient refractive index defect layer is introduced, which can suppress electromagnetic wave of certain frequency and generate the photonic band gap. The finite difference time domain (FDTD) method is used to solve Maxwell equations. The corresponding transmission spectrum lines are studied when the refractive index of defect layer is parabolic. Influences of the refractive index ratio, thickness ratio and cycle number of periodic dielectric layer on the filtering characteristics are analyzed. Results show that a wider filter bandwidth of one-dimensional photonic crystal with gradient refractive index defect layer can be realized by increasing the refractive index ratio. The transmission peak position is affected by changing thickness ratio, and the transmittance is affected by changing the periodic number. Research results have a certain reference value for improving the performance of photonic crystal filters.

Parameter identification of chaotic systems is a key problem in chaos control and synchronization of nonlinear science. An improved quantum genetic algorithm with good global search capability is proposed, and it is used for parameter identification of chaotic systems. The fitness function is constructed by reducing the state synchronization error between the actual system and mathematical model. The parameter identification problem is transformed into a multi-dimensional optimization problem. The hyper-chaotic Chen system is investigated with the improved algorithm, and it is compared with the basic quantum genetic algorithm. Results show that the improved algorithm has better optimizing ability, and it is proved that the improved quantum genetic algorithm is effective and feasible.

The propagation properties of 1+1 dimension Hermite-Gauss beam in nonlocal nonlinear lossy media are investigated by using the variational method. The laws of beam parameters followed when propagating in medium and the critical power required by forming the lossy solitons are obtained. When the initial power is close to the critical power, the beam width expands periodically and obeys the quasi-sine or quasi-cosine law. By comparison, the analytical and numerical solutions using the variational method are in good agreement with a longer distance in beam propagation.

In order to realize the real-time monitoring of the spatial and temporal variation of atmospheric aerosol, a data acquisition and remote monitoring system for Mie scattering atmospheric lidar based on B/S architecture is designed. Real time acquisition of atmospheric echo signal is realized by embedded system built with ARM-Linux platform. The echo signal is processed by using Fernald method. The extinction coefficient curve and time-height -indicator (THI) chart are displayed in real time. The proposed design is based on remote monitoring system with B/S architecture. It has characteristics of monitoring platform-independent and location-independent, and the spatial and temporal variation of atmospheric aerosol obtained by Mie scattering lidar all day can be understand more intuitively. Experiments show that the designed system can display extinction coefficient profile and THI figure in real-time, and has good remote control ability.

A novel fiber-optic current sensor based on a nested fiber grating is proposed. Long period grating fabricated by two-exposure method and Bragg grating are nested to form fiber grating, and it’s used as sensing element. Surface of the nested fiber grating is sputtered with a layer of high resistance Ni-Fe alloy, which is used as heating electrode layer. When the current passes through, the grating region is heated, which leads to center wavelength of grating spectrum shifting. High sensitivity current measurement is realized. Experimental results show that the current response sensitivity of the designed optical fiber current sensor reaches 7.2×10-2 nm/mA. It has the advantages of simple structure, small size, and has wide application value in the field of high sensitivity optical fiber current detection.

A compact dual-parameter fiber sensor based on Fabry-Perot interference(FPI) and fiber Bragg grating (FBG) is proposed, and simultaneous measurement of temperature and strain is realized. A section of end-face-etched multimode fiber (MMF) and a small section of photosensitive fiber (PSF) are fused to form FPI. The flat end face of PSF acts as a reflector of FPI, and FBG is written in PSF. The measured strain sensitivities of FPI and FBG are 8.63 pm/με and 1.11 pm/με, and the temperature sensitivities of them are -1.60 pm/°C and 9.75 pm/°C, respectively. As FBG and FPI have different sensitivities to strain and temperature, they can be utilized together for simultaneous measurement of dual parameters. Experiment results show that the maximal errors are respectively 6.72 με and 0.98 °C for strain and temperature when they are measured simultaneous.

In order to investigate influence of sintering time on hydroxyapatite target, the hydroxyapatite powder with 99% purity is pressed into disc-shaped targets, and the targets are sintered for 12, 16, 20 and 24 h at 800°C in a argon ambience, respectively. Hydroxyapatite targets with different sintering time are detected with X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS). Results show that sintering time has no obvious influence on the crystallinity and composition of hydroxyapatite targets, but it has significant influence on the ratio of Ca to P. The ratio of Ca to P increases when the sintering time increases from 12 h to 20 h, but the ratio decreases when the sintering time increases from 20 h to 24 h. The hydroxyapatite target sintered for 20 h at 800°C has better biocompatibility and stability.

In order to obtain continuous tunable high-frequency microwave signals, a high precision thermoelectric cooler (TEC) temperature control system is designed based on microcontroller. MSP430F149 is used as the control chip of the system. TMP112, a digital temperature sensor, is used to collect temperature information, and the temperature can be controlled by TEC chip driven by the pulse width modulation (PWM) signal from driven circuit. The steady error is about 0.06 °C. The optical fiber temperature is controlled by the temperature controller, and the high-frequency microwave signal from 10.872 GHz to 10.905 GHz is obtained by adjusting the temperature. The signal frequency shift magnitude slope is about 1.1 MHz/°C. A wider range of microwave signals can be obtained by increasing temperature tunig range of the control system.

In order to effectively solve serious network congestion, low data success transmission rate, high data redundancy rate and poor overall network performance in remote geographical area communications network, a new delay/disruption tolerant network (DTN) congestion control routing optimization algorithm is designed based on ant colony optimization mechanism considering the feature of sport regional about network node. Combined the algorithm with pheromone of ant colony optimization mechanism, multiple data transmission between the source and destination nodes is carried out. In the data information transmission direction, average transit hops of network nodes are obtained, and the transit values of network nodes are assessed. Inspired values of ant colony optimization mechanism are referenced. Inspired values of network nodes and the remaining storage capacity of network nodes are associated. Network nodes are combined as evaluation parameters of transit nodes, and the transmission task is completed by selecting network nodes with the largest evaluation parameters. Experiments show that the network congestion is effectively controlled by the algorithm, data success transmission rate is improved, and data redundancy rate is also reduced effectively. The overall network performances are further optimized.

The spin-dependent electron transport properties of quantum waveguide systems with attached stubs in the presence of Rashba spin-orbit coupling (SOC) by recursive Green function (RGF) method are theoretically studied. In the single-stub Rashba SOC quantum waveguide system, the dip-like structure and valley-like structure emerge in the charge conductance spectra due to the stub-induced potential well and SOC-induced potential well. In addition, the peaks of the dip-like and valley-like structure can be controlled by changing the strength of Rashba SOC. At the same time, a series of resonant peaks and dips occur in the charge conductance and spin conductance, at the energies that correspond to the quasi-bound states in the stubs. Moreover, due to the presence of multiple modes and the mode-mixing effect as the number of stubs increases, there are some mini-bands exist in the charge conductance and spin polarization. However, the quantization plateau is gradually recovered, a set of resonances occurs in the charge conductance and spin conductance at the threshold of every transmitted mode when the system is in the presence of an electromagnetic field.

The mean number of phonons of strong-coupled polaron in a parabolic quantum well is investigated by using the variational method combing the linear combination operator and unitary transformation. The relationships among the mean number of phonons of strong-coupled polaron in a parabolic quantum well, confinement strength of quantum well and electron-longitudinal optical phonons coupling strength are derived. Results show that the mean number of phonons of the strong-coupled polaron increases with increasing of quantum well confinement strength and electron-longitudinal optical phonons coupling strength. The mean number of phonons tends to be result of the crystalline material wit decreasing of the quantum well confinement strength. The interaction of the electron and phonons is enhanced with increasing of the confined strength and coupling strength of parabolic quantum well.