Integrated On-line Instrumentation System of Magnetic Properties Measurement

A portable microcomputer-controlled inspection system has been developed for detection of magnetic properties of soft magnetic materials. It incorporates custom designed software for control of the magnetic field during operation such as demagnetization, field sweeping, and for data logging and analysis. Results are recorded using a 12-bit analog to digital converter and are then stored on disk. The magnetic hysteresis loop and Barkhausen noise data can be converted into important magnetic parameters: coecivity, remanence, and hysteresis loss, Barkhausen amplitude, and Barkhausen noise energy. This system incorporated with the magnetostriction, and magnetoacoustic emission, is then related with the nondestructive detection of material degradation.

Magnetic field regression using artificial neural networks for cold atom experiments

Accurately measuring magnetic fields is essential for magnetic-field sensitive experiments in areas like atomic,molecular,and optical physics,condensed matter experiments,and other areas.However,since many experiments are often conducted in an isolated environment that is inaccessible to experimentalists,it can be challenging to accurately determine the magnetic field at the target location.Here,we propose an efficient method for detecting magnetic fields with the assistance of an artificial neural network(NN).Instead of measuring the magnetic field directly at the desired location,we detect fields at several surrounding positions,and a trained NN can accurately predict the magnetic field at the target location.After training,we achieve a below 0.3%relative prediction error of magnetic field magnitude at the center of the vacuum chamber,and successfully apply this method to our erbium quantum gas apparatus for accurate calibration of magnetic field and long-term monitoring of environmental stray magnetic field.The demonstrated approach significantly simplifies the process of determining magnetic fields in isolated environments and can be applied to various research fields across a wide range of magnetic field magnitudes.

Nuclear Magnetic Resonance Measurements of Original Water Saturation and Mobile Water Saturation in Low Permeability Sandstone Gas

We use nuclear magnetic resonance （NMR） and centrifugation to measure the original water saturation and mobile water saturation of cores from the Xujiahe low permeability sandstone gas reservoir, and compare the NMR results with the corresponding field data. It is shown that the NMR water saturation after 300psi centrifugation effectively represents the original water saturation measured by weighing fresh cores. There is a good correlation between mobile water saturation and the water production performance of the corresponding gas wells. The critical mobile water saturation whether reservoir produces water of the Xujiahe low permeability sandstone gas is 6%. The higher the mobile water saturation, the greater the water production rate of gas well. This indicates that well＇s water production performance can be forecasted by mobile water saturation of cores.

Measurement of Electron-Drift Velocity in Ar＋CH4 Mixtures Using Double-Grid Method

Based on analyzing the induced signals from the double-grids of an ionization chamber, the electron-drift time between the two grids is determined and the electron-drift velocity is derived. A waveform digitizer is employed to record pulses from the two grids of the ionization chamber. The electron-drift velocity is measured as a function of the reduced electric field E/p for eight different ratios of Ar＋CH4 mixtures. By analyzing the experimental data of this study, self-consistency of experimental data is achieved, and formulae for calculating electron-drift velocity in any ratio of Ar＋CH4 mixtures are obtained.

Velocity Measurement Based on Laser Doppler Effect

A novel method for velocity measurement is presented. In this scheme, a parallel-linear-polarization dual- frequency laser is incident on the target and senses the target velocity with both the frequencies, which can increase the maximum measurable velocity significantly. The theoretical analysis and verification experiment of the novel method are presented, which show that high-velocity measurement can be achieved with high precision using this method.

Progress in AMS Measurement of 182Hf at CIAE

Accelerator mass spectrometry （AMS） is one of the most promising methods to detect minute amounts of 182Hf. However, the sensitivity of 5×10^-11 for ^182Hf/180Hf obtained previously by the AMS method at China Institute of Atomic Energy （CIAE） cannot meet the requirement of some applications. We present some new improvements of measurement method for AMS measurement of 182Hf at the CIAE HI？13 tandem accelerator system. As a result, a sensitivity of 1.0×10^-11 for 182Hf/180Hf is achieved.

Time-Resolved Measurement of Radiatively Heated Iron 2p-3d Transmission Spectra

An experimental measurement of radiatively heated iron plasma transmission spectra was performed on Shenguang II laser facility. In the measurement, the self？emission spectrum, the backlighting spectrum, and the absorption spectrum were imaged with a flat filed grating and recorded on a gated micro channel plate detector to obtain the time-resolved transmission spectra in the range 10-20 ？ （approximately 0.6-1.3 keV）. Experimental results are compared with the calculation results of an unsolved transition array （UTA） code. The time-dependent relative shift in the positions of the 2p-3d transmission array is interpreted in terms of the plasma temperature variations.

Analysis of The Current Cituation of Solar Radiation Measurement

This paper mainly discusses the development status of solar radiation measurement technology,it expounds the relevant content of the current world radiation measurement datum and its standardization. Article the direct radiation from the sun,the main measuring principle of total radiation and scattering radiation,this paper discusses the different types of radiation survey measuring elements,measuring range,emphasis and the current widespread use of measurement instruments. The development trend of future solar radiation measurement is put forward,and it is emphasized that nanotechnology and spectrum technology will become the focus of solar radiation instrument research and development.

生产率损失测量工具的比较研究

目的 比较可用于卫生技术评估中的生产率损失测量工具,厘清可用于卫生技术评估中的生产率损失测量工具的应用条件,以期为相关研究者在选择生产率损失的测量工具时提供参考。方法 检索PubMed、Web of Science、中国知网、万方、维普等中外数据库,检索时间从数据库建库至2021年11月,由2名研究者按照纳入与排除标准独立筛选文献、识别生产率损失测量工具、提取资料。结果 共识别出5种可用于卫生技术评估领域中的生产率损失测量工具,包括工作能力和活动受损量表(work productivity activity and impairment,WPAI)、工作能力局限调查问卷(work limitations questionnaire,WLQ)、健康与工作绩效问卷(Health and Work Performance Questionnaire,HPQ)、损失产能的估值(Valuation of Lost Productivity Questionnaire,VOLP)和医疗技术评估研究院(Institute for Medical Technology Assessment,IMTA)的生产力成本问卷(IMTA Productivity Questionnaire,IPCQ)。其中WPAI和WLQ是测量属性证据最为充足的工具;VOLP是成本涵盖最全的工具;WLQ是数据敏感性最强的工具;IPCQ是货币转化方法最多的工具;WPAI是获取使用最方便的工具。结论 对于卫生技术评估中的生产率损失测量的标准工具尚未存在统一共识,研究者可根据自身研究选取生产率损失测量工具。

Methodological quality(risk of bias) assessment tools for primary and secondary medical studies: What are they and which is better?

Methodological quality(risk of bias)assessment is an important step before study initiation usage.Therefore,accurately judging study type is the first priority,and the choosing proper tool is also important.In this review,we introduced methodological quality assessment tools for randomized controlled trial(including individual and cluster),animal study,non-randomized interventional studies(including follow-up study,controlled before-and-after study,before-after/pre-post study,uncontrolled longitudinal study,interrupted time series study),cohort study,case-control study,cross-sectional study(including analytical and descriptive),observational case series and case reports,comparative effectiveness research,diagnostic study,health economic evaluation,prediction study(including predictor finding study,prediction model impact study,prognostic prediction model study),qualitative study,outcome measurement instruments(including patient-reported outcome measure development,content validity,structural validity,internal consistency,cross-cultural validity/measurement invariance,reliability,measurement error,criterion validity,hypotheses testing for construct validity,and responsiveness),systematic review and meta-analysis,and clinical practice guideline.The readers of our review can distinguish the types of medical studies and choose appropriate tools.In one word,comprehensively mastering relevant knowledge and implementing more practices are basic requirements for correctly assessing the methodological quality.

INTELLIGENT VIRTUAL CONTROL:MEASURING INSTRUMENT FROM WHOLE TO PART

A new concept called intelligent virtual control (IVC), which can be drivenby measuring functions, is put forward. This small 'intelligent measurement instrument unit (IMIU)',carrying with functions of instrument, consists of different types of intelligent virtualinstrument (IVI) through individual components together as building blocks and can be displayeddirectly on the computer screen. This is a new concept of measuring instrument, and also animportant breakthrough after virtual instrument (VI). Virtual control makes instrument resourcesobtain further exploitation. It brings about a fundamental change to the design and manufacturingmode. The instrument therefore, can not only be produced directly inside a PC, but the product isinvolved in the 'green product' system. So far, all the present digital instruments will grow to bereplaced by intelligent control with green characteristics.

Self-heating Probe Instrument and Method for Measuring High Temperature Melting Volume Change Rate of Material

The castings defects are affected by the melting volume change rate of material. The change rate has an important effect on running safety of the high temperature thermal storage chamber, too. But the characteristics of existing measuring installations are complex structure, troublesome operation and low precision. In order to measure the melting volume change rate of material accurately and conveniently, a self-designed measuring instrument, self-heating probe instrument, and measuring method are described. Temperature in heating cavity is controlled by PID temperature controller; melting volume change rate υ and molten density are calculated based on the melt volume which is measured by the instrument. Positive and negative υ represent expansion and shrinkage of the sample volume after melting, respectively. Taking eutectic LiF＋CaF2 for example, its melting volume change rate and melting density at 1 123 K are -20.6% and 2 651 kg/m–3 measured by this instrument, which is only 0.71% smaller than literature value. Density and melting volume change rate of industry pure aluminum at 973 K and analysis pure NaCl at 1 123 K are detected by the instrument too. The measure results are agreed with report values. Measuring error sources are analyzed and several improving measures are proposed. In theory, the measuring errors of the change rate and molten density which are measured by the self-designed instrument is nearly 1/20-1/50 of that measured by the refitted mandril thermal expansion instrument. The self-designed instrument and method have the advantages of simple structure, being easy to operate, extensive applicability for material, relatively high accuracy, and most importantly, temperature and sample vapor pressure have little effect on the measurement accuracy. The presented instrument and method solve the problems of complicated structure and procedures, and large measuring errors for the samples with high vapor pressure by existing installations.

Accurate Phase Shift Extraction for Generalized Phase-Shifting Interferometry

An accurate phase shift extraction method for generalized phase-shifting interferometry is suggested. Based on the nearly random phase distribution of the diffraction field of the object, a singular formula is derived to calculate the unknown phase shift without the requirements of an iteration process or the selection of the correct value from two or more possible phase shift solutions as needed before. This method can be used in the cases of two or more frames with both smooth and diffusing object surfaces. Computer simulations and optical experiments have satisfactorily verified the efficiency and accuracy of this method.

Automatic Recognition Method for Optical Measuring Instruments Based on Machine Vision

Based on a comprehensive study of various algorithms, the automatic recognition of traditional ocular optical measuring instruments is realized. Taking a universal tools microscope(UTM) lens view image as an example, a 2-layer automatic recognition model for data reading is established after adopting a series of pre-processing algorithms. This model is an optimal combination of the correlation-based template matching method and a concurrent back propagation(BP) neural network. Multiple complementary feature extraction is used in generating the eigenvectors of the concurrent network. In order to improve fault-tolerance capacity, rotation invariant features based on Zernike moments are extracted from digit characters and a 4-dimensional group of the outline features is also obtained. Moreover, the operating time and reading accuracy can be adjusted dy-namically by setting the threshold value. The experimental result indicates that the newly developed algorithm has optimal recognition precision and working speed. The average reading ratio can achieve 97.23%. The recognition method can automatically obtain the results of optical measuring instruments rapidly and stably without modifying their original structure, which meets the application requirements.

Effect of Vortex Stirring on the Dilution of Copper Slag

In order to solve the problem that the vulcanizing agent utilization rate is low and the dilution effect of copper slag is poor,the vortex stirring dilution method was used to improve the conditions of the dilution kinetics and copper recovery.The water model was used to simulate the effect of copper slag dilution.Under the premise of keeping the Reynolds number consistent,silicone oil and glass beads were used instead of copper slag and vulcanizing agent.Based on the relationship between voltage and concentration,the PC6D dual-channel particle concentration measuring instrument was used to study the stirring speed and the insertion depth of the stirring paddle in model experiments,and the suitable conditions were speed 250 rpm and insertion depth 70 mm.The fire dilution of copper slag was done under the conditions.After stirring and sedimentation,the Fe_(3)O_(4) in slag decreased from 22.58% to 4.65%,and the copper content of the slag decreased from 2.94% to 0.34%.The copper recovery was 88.44%.

Theoretical Investigation of Femtosecond-Resolved Photoelectron Spectra of the Li2 Molecule

The time-dependent quantum wave packet method is used to investigate the dynamics for the Li2 molecule, and the time-resolved photoelectron spectra （TRPES） of the Li2 molecule are calculated. At the short delay time, the particular phenomenon of TRPES with four peaks is qualitatively interpreted in a dressed state picture by analyzing wave packet motion on light-induced potential （LIP）. The significant difference in the electronic structure of E1∑g^＋ between the inner and outer turning points has an impact on the TRPES. The control for the first excited state A1∑u^＋ of the initial wave packet is discussed.

Higher Harmonics Generation in Tapping Mode Atomic Force Microscope

The contribution of higher harmonics to the movement of a micro rectangular cantilever in tapping mode AFM is investigated. The dependence between the phase lag of the higher harmonic components and tip-sample separation are found to be an order of magnitude higher than the base one, reflecting an increasing sensitivity to local variations of surface properties compared to the normal phase signal The strong correlation between the higher harmonic amplitude and average sample deformation implies that the higher harmonic amplitude can be taken to monitor the tapping force or as feedback variable to fulfill a constant repulsive force mode.

An Adaptive Fast Multipole Higher Order Boundary Element Method for Power Frequency Electric Field of Substation

An adaptive fast multipole higher order boundary element method combining fast multipole （FM） with a higher order boundary element method is studied to solve the power frequency electric field （PFEF） of substations. In this new technique, the iterative equation solver GMRES is used in the FM, where matrix-vector multiplications are calculated using fast multipole expansions. The coefficients in the preconditioner for GMRES are stored and are used repeatedly in the direct evaluations of the near-field contributions. Then a 500kV outdoor substation is modeled and the PFEF of the substation is analyzed by the novel algorithm and other conventional methods. The results show that, in computational cost and the storages capability aspects, the algorithm proposed in this study has obvious advantages. It is suitable for the calculation of the large-scale PFEF in complex substations and the design of electromagnetic compatibility.

Analysis of Detectors and Transmission Curve Correction of Mobile Rayleigh Doppler Wind Lidar

A mobile molecular Doppler wind lidar （DWL） based on double-edge technique is presented for wind measurement at altitudes from 10 km to 40 km. A triple Fabry-Perot etalon is employed as a frequency discriminator to determine the Doppler shift proportional to the wind velocity. The lidar operates at 355 nm with a 45-cm aperture telescope and a matching azimuth-over-elevation scanner that can provide full hemispherical pointing. In order to guarantee the wind accuracy, different forms of calibration function of detectors in different count rates response range would be especially valuable. The accuracy of wind velocity iteration is improved greatly because of application of the calibration function of linearity at the ultra low light intensity especially at altitudes from 10 km to 40 km. The calibration functions of nonlinearity make the transmission of edge channel 1 and edge channel 2 increase 38.9% and 27.7% at about 1 M count rates, respectively. The dynamic range of wind field measurement may also be extended because of consideration of the response function of detectors in their all possible operating range.