With the development of ion confinement technology and laser cooling technology,the quantum frequency standard is developed from microwave band to optical band,and the uncertainty of ion optical frequency is raised to E-19 magnitude.The ion confinement system is one of the core systems for realizing ion optical frequency standard,which mainly applies the Paul trap to confine ions by the radio frequency field and electrostatic field.We introduce the principle of Paul trap and the equations of ion’s motion.Recent progresses on the ion trap structure in optical frequency standard have been presented,including ring-cap traps,end-cap traps,miniature segmented traps and blades traps.The development of ion traps can help promoting the stability and miniaturization of optical frequency standard.

High-resolution displacement measurement is crucial in lithography,precision machining,biomedical detection,and other fields.In this paper,we propose a novel displacement measurement scheme based on Michelson lasers.Different from the traditional laser interferometers using electronic subdivision interference fringe method,Michelson lasers trace displacement measurement to laser frequency measurement with high resolution.Furthermore,we present and demonstrate a Faraday-Michelson laser utilizing the narrowband Faraday anomalous dispersion atomic filter as the frequency selection device,enabling simultaneous oscillation output of two laser modes,and preliminarily test the displacement measurement resolution of the system.As frequency measurement has a resolution well over 12 digits,our scheme can theoretically reach a displacement measurement resolution in pm or even finer,paving the way for future advancements in high-resolution displacement measurement.

The application of deep learning in chemical metrology has been receiving increasing attention，particularly in the field of spectroscopy.Spectral analysis technology，as an important component of chemometrics，has long played a key role in molecular analysis，structural identification，and quantitative measurement.With the continuous development of deep learning algorithms and computational capabilities，the challenges faced by traditional spectral data analysis methods are gradually being effectively addressed.This research reviews the current applications，technological advantages，and future trends of deep learning in the four major spectroscopic techniques—Infrared spectroscopy (IR)，Ultraviolet spectrum (UV)，Nuclear Magnetic Resonance (NMR)，and Mass Spectrometry (MS).It analyzes how deep learning，through big data training，automated feature extraction，and nonlinear modeling，enhances the accuracy and efficiency of spectral analysis.With the improvement of computational power，further optimization of deep learning models，and the continuous accumulation of big data，the application of deep learning in chemical metrology，particularly in the field of spectral analysis，is advancing towards a more intelligent and automated direction.This is bringing about revolutionary changes in chemical analysis technology and providing strong support for scientific research and industrial applications.

This research presents a new calibration method for IQ channel amplitude and phase imbalance in a sideband separation receiver.In the new method，the equation set is established based on the rejection ratio difference and the information of gain imbalance between different curves in the separation rejection ratio curve cluster.Then，the solution process is derived，and the aim that calibrating the receivers only by adjusting the digital back-end calibration coefficient is accomplished.This study conducts MATLAB numerical simulation experiments based on the proposed calibration method.The simulation results demonstrate that the method achieves a separation rejection ratio exceeding 80 dB,thereby validating the feasibility and effectiveness of the calibration method.The new method solves the defect that the traditional calibration method of the sideband separation receiver needs to obtain both amplitude and phase information at the IF port in order to realize the calibration of the receiver.

In order to achieve better traceability results and improve the reliability of the time traceability system based on remote time transfer method,a fusing traceability method was studied.The multi-method time & frequency traceability comparison device was developed by disciplining rubidium clocks with reference to UTC(BIRM) and using GNSS common-view and two way optical fiber methods,and a remote time traceability comparison system was preliminarily constructed based on the device.Through experimental verification,the multi-method time & frequency traceability comparison device replicated high-performance real-time time scale synchronized with UTC(BIRM) at remote user station.The time deviation of real-time time scale by GNSS common-view is within ±4 ns,and the time deviation of real-time time scale by two way optical fiber is within ±2 ns.

OCXO（Oven Controlled Crystal Oscillator）is one of the key devices in electronic equipment,which is widely used in mobile communication,navigation radar and metrology measuring equipment.A large number of domestic frequency source stability tests adopt the test method of frequency comparison,which requires a high stability reference source as a reference for short-term frequency stability,but the high performance ultra-stable OCXO usually used for measurement is expensive and the procurement cycle is long,which limits the test application of many engineering projects.This paper presents a 10 MHz OCXO with excellent short-term stability.The product uses a TO packaging SC cut crystal resonator.The oscillating part is a Colpitts circuit and the temperature regulator part uses a modified proportional integrated temperature-controlled circuit with dual Operational amplifiers.The experiment results show that the OCXO’s short-term stability is 1.46E-13/1 s,1.52E-13/10 s;the phase noise is -120 dBc/Hz@1 Hz,-137 dBc/Hz@10 Hz and -147 dBc/Hz@100 Hz;the frequency-temperature stability is ±2.98E-10 at -40~70 ℃.

Aiming at the lack of domestic means of fixing and traceability of pulsed magnetic field，develops a high-accuracy pulsed magnetic field measurement device based on Faraday magnetotelluric effect.Taking a pulsed magnetic field generator as an example，the feasibility of using the magnetotelluric effect for the traceability of strong pulsed magnetic field is verified by examining the linearity between the magnetic field strength of the pulsed magnetic field generator and the deflection angle of the affected polarized light，and the results show that there is a significant sinusoidal fitting relationship between the pulsed magnetic field strength and the amplitude of the change of light intensity.The polarized light intensity is used as an intermediate medium to link the pulsed magnetic field and the standard constant magnetic field，and two methods of optical range ratio and optical intensity ratio are proposed to solve the traceability problem of the standard device for metrological examination of the strong pulsed magnetic field.

The article analyzes the definition and calculation methods of random error and measurement uncertainty,and determines that there is a similarity in nature between the two,while there are also differences between them.Random error is calculated from the standard deviation of the results of multiple repeated measurements,and uncertainty not only includes the results obtained by statistical methods,but also other factors that may have a random impact on the calibration results.By comparing and analyzing,it can effectively promote the reader’s understanding of uncertainty.Then,taking the uncertainty evaluation of precision pressure gauge as an example,the application of typical uncertainty evaluation report to quickly carry out the uncertainty evaluation of actual calibration data is discussed,and the suggestions for giving the actual uncertainty when reporting the calibration results are put forward.

The underwater acoustic channel is complicated，and the transmission of weak acoustic signals is often interfered by other signals.In order to obtain a higher signal-to-noise ratio，the acoustic signals received by hydrophones are usually filtered.Based on the FPGA hardware platform，using the FIR filtering algorithm and through the self-parsing algorithm of filter parameters to achieve precise control of the cut-off frequency and steep transition band，a broadband programmable filter for underwater acoustic metrology is designed.The cut-off frequency is adjustable from 1 Hz to 1.59 MHz，and it can be configured as high-pass，low-pass，band-pass，or band-stop.The out-of-band attenuation is greater than 48 dB/Octave.The parameters of the metrology-grade programmable filter can be configured via RS232，GPIB，or LAN.The results of design simulation and application test show that the programmable filter can be applied to various underwater metering scenarios with different filtering requirements.The parameters are flexible and changeable，and the real-time performance is strong，which can meet the needs of underwater acoustic metering.

To address the issue of low binding force of the Fréchet Inception Distance (FID) metric in cross-domain image generation evaluation,a domain difference calculation method based on the Multi-Level Feature Alignment Distance (MLFAD) is proposed.By introducing a multi-level feature extraction and feature alignment mechanism,a comprehensive measurement of the distribution differences of generated images and real images at different hierarchical feature scales is achieved,which more accurately reflects the detailed and global information of the images and significantly enhances the binding force on the generated images.The experimental results show that the performance of MLFAD is significantly better than that of the FID.In cross-domain image generation tasks such as image translation,style transfer,image restoration,and image enhancement,the domain difference has been reduced by 31.7%,26.8%,41.1%,and 34.6%,respectively.Therefore,MLFAD which has excellent accuracy and stability in the evaluation of cross-domain image generation tasks,significantly improves the clarity,detail restoration,and color accuracy of the generated images.

Environmental stray magnetic fields and those generated by circuit components can cause frequency shifts in the transition spectral lines of CPT（Coherent Population Trapping） atomic clocks,thus affect their long-term frequency stability.To reduce the interference magnetic fields introduced by traditional electric heating temperature control devices,a dual-layer heating z-type structure was adopted.Simulation was conducted using finite element analysis software to compare the distribution of axial magnetic fields generated by traditional and novel heating elements in an atomic cell.Results indicated that the interference magnetic field intensity of the dual-layer z-type heating structure could be reduced to 0.05% of that of traditional heating elements,and magnetic field uniformity improved by over 1 700 times.Further adjustments of the currents in each layer of the dual-layer heating elements could reduce the interference magnetic field to less than 15 nT,and the magnetic field fluctuation range due to temperature adjustments was just 0.33 nT.Tests in a magnetically shielded environment showed that the actual results were consistent with the simulations,significantly enhancing the long-term frequency stability of the CPT atomic clock.

This paper presents a mathematical model of the frequency closed-loop control system for an ion microwave clock,constructed using the Simulink platform based on the system architecture and operational principles of the clock.The model simulates the dynamic response of a typical closed-loop control process,with a detailed analysis of key parameters,including the Proportional,Integral,and Derivative (PID) control coefficients,closed-loop response time,ion number decay characteristics,and their impacts on system’s stability and accuracy.Through comprehensive optimization of these parameters,this study elucidates their roles in enhancing system performance and investigates the effects of different parameter configurations on frequency stability.The findings provide a practical simulation and theoretical framework for the design and optimization of ion microwave clocks,contributing to improved long-term stability and precision.The proposed methodology and conclusions are also applicable to other frequency-controlled high-precision time and frequency devices,offering valuable insights for engineering applications in related fields.

The link noise computing method of total noise weighted average has realized the 100% correction of link noises which have reciprocating fluctuation characteristics in theory.For link noises without such characteristics or those with extremely long fluctuation periods，the method cannot provide effective correction.Therefore，this method cannot be directly used to calculate the link noise of fiber optic time-frequency transfer link.But this method could be used for fiber optic time-frequency transfer link，if the initial phase difference，frequency difference，and frequency drift difference between the atomic clocks in different station had been calculated out by two-way satellite time-frequency transfer.Through simulation，reduce the calculation deviation of link noise to 0.1 ns，at least 6 atomic clocks are required.By increasing the number of atomic clocks involved in the calculation，this method can infinitely approach zero in calculation bias.

The atomic time scale is the reference for the master clock frequency sources in time keeping laboratories around the world.Since most time-keeping laboratories are equipped with only a single type of atomic clock，a single time-scale calculation method can achieve good results.With the development of multiple types of atomic clocks in our country，using a single time scale calculation method will not give full play to the performance advantages of different types of atomic clocks.In order to calculate the time scale more reasonably，we propose to choose different time scale algorithms for different clock ensemble configurations.The characteristics of hydrogen masers and cesium atomic clocks are analyzed，including long and short term fluctuation，frequency stability and frequency drift.Then，we propose an ALGOS-LIKE algorithm，based on the two types of atomic clocks，the ALGOS-LIKE and AT1 time scale algorithms are used to calculate,compare and analyze.The results show that i) under the configuration of the cesium atomic clock ensemble，the time scales generated by the AT1 algorithm are of the order of E-14 for hour and E-15 for 5 days，and the long-term and short-term frequency stability are better than the calculation output of the dynamic ALGOS-LIKE algorithm;ii)under the clock ensemble configuration of the hydrogen maser ensemble，the ALGOS-LIKE algorithm is better，and the long-term frequency stability is improved compared with the AT1 time scale algorithm.

Emission spectroscopy is an important non intrusive measurement method for measuring key parameters of plasma.Although conventional emission spectroscopy measurement methods can obtain information on key parameters such as electron temperature and electron density，traditional emission spectroscopy models actually include collision radiation processes of many atomic energy levels.Researchers mainly analyze the parameters involved in collision radiation processes based on cross-sectional approximation calculation methods or empirical formulas.The analysis model is relatively complex.In response to the above issues，this article conducted a simplified analysis of plasma emission spectroscopy，aiming to establish a more concise coronal model of emission spectra applied to the 750 nm and 751 nm characteristic wavelength spectral lines of Ar，and build an experimental system based on inductively coupled plasma source to achieve non intrusive measurement of plasma electron temperature and electron density.Through experimental verification of the model，it provides technical reference for the study of key parameters of plasma measured by emission spectroscopy.

With the advancement of laser absorption spectroscopy technology in applications under complex conditions and the demand for high-precision measurements,supercontinuum laser absorption spectroscopy measurement technology has begun to receive widespread attention.This study conducts research on temperature measurement technology based on supercontinuum laser absorption spectroscopy,developing a supercontinuum spectral feature matching method for simultaneously resolving parameters such as temperature and concentration.Simulation calculations and experimental validations were carried out.Through simulation calculations,absorbance data were obtained for temperature resolution in the range of 300 K to 2 600 K,verifying the feasibility of this method for accurate temperature measurement.A measurement system was also built,and experimental validation was conducted at eight temperature points from 473 K to 1 173 K using the spectral absorption of water molecules in the range of 7 433 cm^-1 to 7 446 cm^-1.By synchronously fitting the baseline correction parameters,time-frequency conversion parameters,and the parameters to be measured,experimental temperature measurements based on the supercontinuum spectral feature matching method were achieved,with a maximum relative error of -1.98% in temperature measurement.The experimental results demonstrate the accuracy of the supercontinuum spectral feature matching method in temperature measurement.

Angle measurement,a core task in physics,has advanced from geometric methods to highly precise technologies.It plays a critical role in scientific research,precision manufacturing,and satellite positioning.However,traditional angle measurement methods,including non-interference methods,interference methods,electromagnetic,and inertial method,face inherent limitations in resolution.To address this limitation,an angle-to-frequency conversion measurement technique has been proposed.Leveraging the high sensitivity of narrow-band interference filter external cavity diode lasers (ECDLs) to angular changes of the interference filter,the filter is fixed to the measured object,converting small angular variations into changes in the laser frequency.By using a stable reference frequency source and employing beat frequency comparison,the frequency shifts of the output laser are precisely detected,enabling ultra-high-precision angular measurements of the device.Compared with traditional angle measurement methods,this approach transforms angular measurement into frequency measurement,significantly enhancing the capability for precision measurements of small angles,aiming to achieve an angular resolution on the order of 0.000 1 arcseconds.