We report a new design of microwave source for X-band electron paramagnetic resonance spectrometer. The microwave source is equipped with a digital automatic frequency control circuit. The parameters of the digital automatic frequency control circuit can be flexibly configured for different experimental conditions, such as the input powers or the quality factors of the resonator. The configurability makes the microwave source universally compatible and greatly extends its application. To demonstrate the ability of adapting to various experimental conditions, the microwave source is tested by varying the input powers and the quality factors of the resonator. A satisfactory phase noise as low as -135 dBc/Hz at 100-kHz offset from the center frequency is achieved, due to the use of a phase-locked dielectric resonator oscillator and a direct digital synthesizer. Continuous-wave electron paramagnetic resonance experiments are conducted to examine the performance of the microwave source. The outstanding performance shows a prospect of wide applications of the microwave source in numerous fields of science.

We report a new design of resonant cavity for a W-band electron paramagnetic resonance(EPR)spectrometer.An im-proved coupling-adjusting mechanism,which is robust,compact,and suits with both solenoid-type and split-pair magnets,is utilized on the cavity,and thus enables both continuous-wave(CW)and pulsed EPR experiments.It is achieved by a tiny metal cylinder in the iris.The coupling coefficient can be varied from 0.2 to 17.9.Furthermore,two pistons at each end of the cavity allow for adjustment of the resonant frequency.A horizontal TE011 geometry also makes the cavity compatible with the two frequently used types of magnets.The coupling-varying ability has been demonstrated by reflection coefficient(S11)measurement.CW and pulsed EPR experiments have been conducted.The performance data indicates a prospect of wide applications of the cavity in fields of physics,chemistry and biology.

A new multifunction X-band electron paramagnetic resonance (EPR) spectrometer is designed and produced, which is equipped with a new operation system based on the EPR control and readout system (CRS). The new continuous-wave (cw) dual-mode resonator and the dielectric resonators for respectively the pulsed EPR and transient EPR (trEPR) are designed purposely. The adoption of CRS system improves significantly the integration and expandability. The spectrometer is equipped with cryogen-free EPR variable temperature system with a range of 6~300 K. Thereafter, three typical samples are used to demonstrate the elegant design of the spectrometer by the cw dual-mode EPR, pulsed EPR and trEPR experiments. Perspectively, this design herein will be a criterion or option of the new generation of EPR spectrometer.

We report a new design of resonant cavity for W-band EPR spectrometer. It suits with both solenoid-type and split-pair magnets. The cavity operates on the TE_011 mode, where the microwave magnetic field is along the cylindrical axis. Its cylindrical axis is horizontal, so the magnetic field of the microwave is always perpendicular to the vertical external magnetic field provided by a solenoid-type magnet. By rotating the cavity, the microwave magnetic field can also be perpendicular to a horizontal external field when a split-pair magnet is used. Furthermore, a tiny metal cylinder allows for the adjustment of coupling. This enables both continuous-wave (CW) and pulsed EPR experiments. The coupling-varying ability has been demonstrated by reflection coefficient (S11) measurement, and CW and pulsed EPR experiments have been conducted. The performance data indicates a prospect of wide applications of the cavity in the fields of physics, chemistry and biology.

In order to analysis the consistency control capability and control strategy of UAVs (unmanned aerial vehicles, UAVs) group after which being released from the carrier, the consistency analysis model are brought out based on the Vicsek model which can deal with the consistency of multi-agent. And the improved Vicsek with variable rate, local FOV and leadership has been given considering that the UAVs is variable rate, the sensor vision field is limited and the formation has leader in practical application. At the last, the simulation and analysis of the given example are done. The simulations results show that the given models can effectively measure the consistency of UAVs group and the consistency can be controlled by adjust the parameters of the control model.

军用直升机的主动防御技术是未来提高军用直升机战场生存力的创新性前沿技术.针对军用直升机特别是运输类、战勤保障类直升机在现代作战环境中缺乏主动防御手段,易受攻击且毁伤代价大的弱点,首先提出军用直升机加装主动防御系统的原理和应用需求,然后分析国内外现有军用直升机主动防御技术和装备,最后根据作战应用原理详细分析了主动防御系统应该解决的主要关键技术.可为未来军用直升机的主动防御技术研究提供借鉴.

Molecular qubits are promising as they can benefit from tailoring and versatile design of chemistry. It is essential to reduce the decoherence of molecular qubits caused by their interactions with the environment. Herein the dynamical decoupling (DD) technique is utilized to combat such decoherence. The coherence time for a transition-metal complex (PPh 4 ) 2 [Cu(mnt) 2 ] is prolonged from 6.8 μs to 1.4 ms. The ratio of the coherence time and the length of π /2 pulse, defined as the single qubit figure of merit ( Q M ), reaches 1.4 × 10 5 , which is 40 times greater than what previously reported for this molecule. Our results show that molecular qubits, with milliseconds coherence time, are promising candidates for quantum information processing.

Dynamical phase transitions (DPTs), characterized by nonanalytic behaviors in time domain, extend the equilibrium phase transitions to far-from-equilibrium situations. It has been predicted that DPTs can be precisely identified by the discontinuities of the Pancharatnam geometric phase (PGP) during the time evolution. However, PGP always mixes with dynamical phase and the experimental observation of DPTs by PGP is still absent. Here, we theoretically present a novel scheme for eliminating the dynamical phase by taking advantage of chiral symmetry in the Su-Schrieffer-Heeger (SSH) model and experimentally observe DPTs by directly measuring PGP in a quenched topological nanomechanical lattice. Time-dependent topological structures of the SSH model are configured by eight strong-coupled high-quality-factor nanomechanical oscillators. By measuring the vibration phase and the normalized amplitude of the edge oscillator, we show a direct classical analog of DPTs. Furthermore, we experimentally demonstrate the robustness of DPTs against weak structure disorders, and numerically explore the relation between DPTs and the equilibrium phase boundary. This work not only establishes the quantitative method to identify DPTs, but also opens the door for studying nonequilibrium topological dynamics with a well-controlled nanomechanical system.

We report a broadband electron paramagnetic resonance (EPR) spectrometer that operates continuously in the frequency range from 1 to 15 GHz. A broadband metallic coplanar waveguide is utilized as the probe. The system is capable of performing EPR measurements in both continuous wave and pulsed modes. Its performance has been tested with a sample, named 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl powder, at room temperature. In the continuous wave mode, the sensitivity of the spectrometer is estimated to be 3.3×1012 spins/gaussHz at 13 GHz. In the pulsed mode, inversion recovery experiments were carried out to obtain the spin-lattice relaxation time of the sample.

Airborne store management system is an important subsystem of aerial integrated avionic system, which plays an important role in the combat capability of combat aircraft. The development process of airborne store management technology is introduced, the function and composition of airborne store management system are analyzed in detail. The key technology and development require of the next generation airborne store management system are presented. This can provide the direction and thinking for the research of airborne store management system.

Berry phase, the geometric phase accumulated in cyclic adiabatic evolution, has been commonly used to define topological invariants for equilibrium states. Pancharatnam geometric phase, a purely geometric phase accumulated in generic time-evolution, extends the Berry phase to non-adiabatic and non-cyclic dynamics. Theoretically, the Pancharatnam geometric phase can perfectly identify dynamical phase transitions in quenched systems, which are analog to equilibrium phase transitions in the Ginzburg-Landau paradigm. However, due to the great challenge in eliminating the dynamical phase during a non-cyclic evolution, it is hard to observe the Pancharatnam geometric phase in dynamical phase transitions. Here, we directly observe the Pancharatnam geometric phase after sudden quenches from a topological edge state in the Su-Schrieffer-Heeger model, which is realized by a reconfigurable array of nanomechanical oscillators. Due to the chiral symmetry in our system, the initial edge state equally populates all symmetrical pairs of final eigenstates and so that the dynamical phase is naturally eliminated. We found that, the Pancharatnam geometric phase jumps $pi$ at each critical time when dynamical phase transition takes place, otherwise the Pancharatnam geometric phase keeps unchanged. This work not only provides a quantitative method to identify dynamical phase transitions, but also paves the way to reveal the bulk-edge correspondence for dynamical phase transitions in topological systems.

We report an X-band pulsed electron paramagnetic resonance (EPR) spectrometer using a Field-Programmable-Gate-Array (FPGA) based pulse generator. The microwave (MW) pulse length and pulse-pulse interval can be adjusted with 50 ps time resolution. A FPGA based pulse generator is utilized to achieve such time resolution. There are eight pulse channels integrated in the pulse generator. Each channel outputs rectangular pulses with 50 ps time resolution. The spectrometer includes a pulse forming unit, where four high-speed PIN diode switches are controlled by the pulse generator to generate MW pulses. A commercial digital storage oscilloscope is used to record the EPR signal. A customized software is developed to control the components of the spectrometer and to perform data processing task. The usefulness of high time resolution is demonstrated by the results of Rabi oscillation.

We report on coplanar waveguides (CPWs) designed for optically detected magnetic resonance of nitrogen-vacancy (NV) centers in diamonds. A broad band up to 15.8 GHz has been realized, which ensures that the electron spins can be manipulated under external magnetic fields up to 5000 G. The conversion factor of CPW has been measured by Rabi nutation experiments, which ranges from 6.64 G W−1/2 to 10.60 G W−1/2 in the frequency band from 0.76 GHz to 17.3 GHz. Broadband CPWs also provide high quality control pulses due to the minimization of the distortion. These characteristics will find potential applications in NV-based quantum information processing and single spin magnetometry.

A highly integrated, high performance, and re-configurable device, which is designed for the Nitrogen-Vacancy (N-V) center based quantum applications, is reported. The digital compartment of the device is fully implemented in a Field-Programmable-Gate-Array (FPGA). The digital compartment is designed to manage the multi-function digital waveform generation and the time-to-digital convertors. The device provides two arbitrary-waveform-generator channels which operate at a 1 Gsps sampling rate with a maximum bandwidth of 500 MHz. There are twelve pulse channels integrated in the device with a 50 ps time resolution in both duration and delay. The pulse channels operate with the 3.3 V transistor-transistor logic. The FPGA-based time-to-digital convertor provides a 23-ps time measurement precision. A data accumulation module, which can record the input count rate and the distributions of the time measurement, is also available. A digital-to-analog convertor board is implemented as the analog compartment, which converts the digital waveforms to analog signals with 500 MHz lowpass filters. All the input and output channels of the device are equipped with 50 Ω SubMiniature version A termination. The hardware design is modularized thus it can be easily upgraded with compatible components. The device is suitable to be applied in the quantum technologies based on the N-V centers, as well as in other quantum solid state systems, such as quantum dots, phosphorus doped in silicon, and defect spins in silicon carbide.

Accurately intercept the supersonic moving target which speed is not less than 3Mach within 300m is the basic requirement of the super close-in antimissile system. So the fire control system must can brought out the accurately shoot parameter in limit time. The accurate tracking filter and predictive the future flying position within 1.5s quickly for the air arriving target are the core of the super close-in antimissile system to improve the shoot precision. Therefore, The moving method of near and high speed target is built firstly, afterward the target tracking and prediction algorithms based on adaptive Kalman filter are brought out. Lastly, the feasibility and validity of the algorithm are validated via by the factual flying data. The results show that the method and algorithm can preferably meet the requirement of tracking and prediction for the super close-in antimissile system.

The periodic skip-glide trajectory models for hypersonic vehicle in near space were brought out and simulated in this paper. Firstly, the basic concepts of hypersonic vehicle and different trajectory modes were introduced in detail. Then, the three degrees of freedom model of hypersonic vehicle was given. Lastly, the model was simulated and analyzed using MATLAB. The difference changing trend of periodic trajectory, velocity, effective range, trajectory obliquity and dynamic pressure are given. How the main factors such as trajectory obliquity, launch orientation affect the periodicity was also studied. The primary simulations show that the periodic trajectory of hypersonic vehicle helpful in studying new space vehicle.

Intelligent assistant decision-making system is more and more important in modern war along with high-tech of weapon, complexity of battlefield and quicken of combat rhythm. For the requirement of intelligent and independence of unmanned aerial vehicle, based on the merits and advantage of probability graphical models on uncertainty inference, the tactics. decision-making modeling of UAV with probability graphical models was brought forward. The modeling flow and inference algorithm of UAV based on Bayesian inference algorithm has been given out. The method has been tested with a given conditions. The simulation results have showed that the tactics decision-making models could improve the decision-making accuracy and intelligent and the algorithm is simple, perspicuity and apt realization.

Aim at the target characters information of aerial optical-electronic sensors system,the fuzzy Bayesian network model was brought out for threat assessment to assist the decision maker.Firstly,the method studies on the target characters and the influence on threat degree of aerial optical-electronic sensors' information in detail.Secondly,the appropriate characters are selected and the crisp variables are fuzzed by fuzzy theory.Then the fuzzy Bayesian network model of target threat assessment is established accordingly.Lastly,these are fed into fuzzy Bayesian networks that perform inference via belief propagation for threat assessment.The inference results can provide decision-maker with technique foundation.A simulation example of the whole threat assessment process demonstrates the validity of the model and the reliability of the inference results.

The research aims at cooperative path planning of multiple aircrafts, the path planning problem and path planning constraint condition are representation. By using hierarchical decomposition, the cooperative path planning is divided into different hiberarchies, which are path planning, cooperative manager and trajectory smoother. Considering threaten cost of each aircraft, the length of route and the demand for time, with bringing in restrict condition of flight capability, the cooperative path planning of multi-aircrafts aimed on single target and multi-targets is realized. Simulation result shows that the time arriving at object of each aircraft is in good cooperation.

Aim at the information of aerial optical-electronic sensors, the multi-phase information fusion model was built for situation estimation. The method first builds a data association of target flight path with fuzzy cluster based on aerial optical-electronic sensors' information. The data fusion of target information is done next via maximum likelihood estimation on cluster attribute. Then the uniform expression for target feature was gained. These are then fed into fuzzy Bayesian networks that perform inference via belief propagation for situation estimation. The inference result can provide decision-maker with technique foundation. A simulation example of the whole situation estimation process demonstrates the validity of the model and the reliability of the inference results.