THE INFLUENCE OF THE DIFFERENT DISTRIBUTEDPHASE-RANDOMIZED ON THE EXPERIMENTAL DATA OBTAINEd IN DYNAMIC ANALYSIS

In this paper the influence of the differently distributed phase-randontized to the data obtained in dynamic analysis for critical value is studied.The calculation results validate that the sufficient phase-randomized of the different distributed random numbers are less influential on the critical value . This offers the theoretical foundation of the feasibility and practicality of the phase-randomized method.

Finite Element Simulation of Flexible Roll Forming with Supplemented Material Data and the Experimental Verification

Flexible roll forming is a promising manufacturing method for the production of variable cross section products. Considering the large plastic strain in this forming process which is much larger than that of uniform deformation phase of uniaxial tensile test, the widely adopted method of simulating the forming processes with non-supplemented material data from uniaxial tensile test will certainly lead to large error. To reduce this error, the material data is supplemented based on three constitutive models. Then a finite element model of a six passes flexible roll forming process is established based on the supplemented material data and the original material data from the uniaxial tensile test. The flexible roll forming experiment of a B pillar reinforcing plate is carried out to verify the proposed method. Final cross section shapes of the experimental and the simulated results are compared. It is shown that the simulation calculated with supplemented material data based on Swift model agrees well with the experimental results, while the simulation based on original material data could not predict the actual deformation accurately. The results indicate that this material supplement method is reliable and indispensible, and the simulation model can well reflect the real metal forming process. Detailed analysis of the distribution and history of plastic strain at different positions are performed. A new material data supplement method is proposed to tackle the problem which is ignored in other roll forming simulations, and thus the forming process simulation accuracy can be greatly improved.

Design of Experimental Data Publishing Software for Neutral Beam Injector on EAST

Neutral Beam Injection （NBI） is one of the most effective means for plasma heating. Experimental Data Publishing Software （EDPS） is developed to publish experimental data to get the NBI system under remote monitoring. In this paper, the architecture and implementation of EDPS including the design of the communication module and web page display module are presented. EDPS is developed based on the Browser/Server （B/S） model, and works under the Linux operating system. Using the data source and communication mechanism of the NBI Control System （NBICS）, EDPS publishes experimental data on the Internet.

RECONSTRUCTION OF PART OF AN ACTUAL BLAST-WAVE FLOW FIELD TO AGREE WITH EXPERIMENTAL DATA BY USING NUMERICAL METHOD WITH HIGH IDENTIFICATION

In this paper, on the basis of experimental data of two kinds of chemical explosions, the piston-pushing model of spherical blast-waves and the second-order Godunov-type scheme of finite difference methods with high identification to discontinuity are used to the numerical reconstruction of part of an actual hemispherical blast-wave flow field by properly adjusting the moving bounary conditions of a piston. This method is simple and reliable. It is suitable to the evaluation of effects of the blast-wave flow field away from the explosion center.

Research on the Application of Intelligence Teaching Mode of Superstar Platform in the Teaching of Experimental Design and Data Processing

Experimental Design and Data Processing is an important core professional basic course for food science majors.This course is theoretical and practical,and there are many formulas,abstract contents and difficult to understand,and there are some problems in the teaching process,such as students1 poor interest in learning,insufficient mastery of what they have learned,and inability to combine theory with practice organically.Through analyzing the existing problems,this paper puts forward some reform measures for the teaching mode of experimental design and data processing by using the intelligent teaching of Superstar platform.

A method for extracting the preseismic gravity anomalies over the Tibetan Plateau based on the maximum shear strain using GRACE data

The occurrence of earthquakes is closely related to the crustal geotectonic movement and the migration of mass,which consequently cause changes in gravity.The Gravity Recovery And Climate Experiment(GRACE)satellite data can be used to detect gravity changes associated with large earthquakes.However,previous GRACE satellite-based seismic gravity-change studies have focused more on coseismic gravity changes than on preseismic gravity changes.Moreover,the noise of the north–south stripe in GRACE data is difficult to eliminate,thereby resulting in the loss of some gravity information related to tectonic activities.To explore the preseismic gravity anomalies in a more refined way,we first propose a method of characterizing gravity variation based on the maximum shear strain of gravity,inspired by the concept of crustal strain.The offset index method is then adopted to describe the gravity anomalies,and the spatial and temporal characteristics of gravity anomalies before earthquakes are analyzed at the scales of the fault zone and plate,respectively.In this work,experiments are carried out on the Tibetan Plateau and its surrounding areas,and the following findings are obtained:First,from the observation scale of the fault zone,we detect the occurrence of large-area gravity anomalies near the epicenter,oftentimes about half a year before an earthquake,and these anomalies were distributed along the fault zone.Second,from the observation scale of the plate,we find that when an earthquake occurred on the Tibetan Plateau,a large number of gravity anomalies also occurred at the boundary of the Tibetan Plateau and the Indian Plate.Moreover,the aforementioned experiments confirm that the proposed method can successfully capture the preseismic gravity anomalies of large earthquakes with a magnitude of less than 8,which suggests a new idea for the application of gravity satellite data to earthquake research.

经济学专业数据分析类课程实验实践的融合发展研究

当前,高等学校经济学专业数据分析类课程实验教学与实践融合度较差,实践教学设计与当前企业人才需求不符。因此要通过搭建实践教学平台,将经济学专业课程、数据分析课程实验教学、实践教学、理论实践竞技等进行融合,培养学生数据分析思维,提升分析理论与方法的实践应用能力,培养复合型应用型经济人才。

Computer Management of Quantitative Analysis Chemistry Experiment

The application of computer in the quantitative analysis chemistry experiment is a chemistry experiment teaching applications software, developed by Visual Basic （6.0）, based on the content of quantitative analysis chemistry experiment of chemistry major in higher institute. This software has the function of the automatic processing the experimental data, the automatic generation of test report copies, and the automatic evaluation of students＇ experimental results, which solve the reliability, objectivity and accuracy problems of the students＇ experiment data processing and evaluation, and avoid interference with human factors. The software has the characteristic of the easy installation, the easy operation, the strong practicability, pertinence, the systematicness and the running stability, so it provides a platform in the quantitative analysis chemistry experiment for the students＇ assessment system of automatic processing, and it has a high popularization value. The project＇s technical route design is reasonable, the research method is correct, and the experimental data processing results are reliable, which has reached the leading domestic level in the quantitative analysis chemistry experiment teaching field of computer data processing. And this project has been through the achievements appraisal of Gansu Provincial Sci. ＆ Tech. Department.

Experimental Investigation and Semi-Active Control Design of A Magnetorheological Engine Mount

In this paper;the dynamic characteristics of a semi-active magnetorheological fluid(MRF)engine mount are studied.To do so,the performance of the MRF engine mount is experimentally examined in higher frequencies(50~170 Hz)and the various amplitudes(0.01~0.2 mm).In such an examination,an MRF engine mount along with its magnetically biased is fabricated and successfully measured.In addition,the natural frequencies of the system are obtained by standard hammer modal test.For modelling the behavior of the system,a mass-spring-damper model with tuned PID coefficients based on Pessen integral of absolute error method is used.The parameters of such a model including mass,damping ratio,and stiffness are identified with the help of experimental modal tests and the recursive least square method(RLS).It is shown that using PID controller leads to reducing the vibration transmissibility in the resonance frequency(=93.45 Hz)with respect to the typical passive engine mount by a factor of 58%.The average of the vibration transmissibility decreasing is also 43%within frequency bandwidth(50~170 Hz).

Evaluation of a Micro-scale Wind Model's Performance over Realistic Building Clusters Using Wind Tunnel Experiments

The simulation performance over complex building clusters of a wind simulation model（Wind Information Field Fast Analysis model, WIFFA） in a micro-scale air pollutant dispersion model system（Urban Microscale Air Pollution dispersion Simulation model, UMAPS） is evaluated using various wind tunnel experimental data including the CEDVAL（Compilation of Experimental Data for Validation of Micro-Scale Dispersion Models） wind tunnel experiment data and the NJU-FZ experiment data（Nanjing University-Fang Zhuang neighborhood wind tunnel experiment data）. The results show that the wind model can reproduce the vortexes triggered by urban buildings well, and the flow patterns in urban street canyons and building clusters can also be represented. Due to the complex shapes of buildings and their distributions, the simulation deviations/discrepancies from the measurements are usually caused by the simplification of the building shapes and the determination of the key zone sizes. The computational efficiencies of different cases are also discussed in this paper. The model has a high computational efficiency compared to traditional numerical models that solve the Navier–Stokes equations, and can produce very high-resolution（1–5 m） wind fields of a complex neighborhood scale urban building canopy（～ 1 km ×1km） in less than 3 min when run on a personal computer.

Numerical-experimental method for elastic parameters identification of a composite panel

A hybrid numerical-experimental approach to identify elastic modulus of a textile composite panel using vibration test data is proposed and investi- gated. Homogenization method is adopted to predict the initial values of elastic parameters of the composite, and parameter identification is transformed to an optimization problem in which the objective function is the minimization of the discrepancies between the experimental and numerical modal data. Case study is conducted employing a woven fabric reinforced composite panel. Three parameters （Ell, E22, G12） with higher sensitivities are selected to be identified. It is shown that the elastic parameters can be accurately identified from experimental modal data.

Evolution and analysis of gas sorption-induced coal fracture strain data

Although coal swelling/shrinking during coal seam gas extraction has been studied for decades,its impacts on the evolution of permeability are still not well understood.This has long been recognized,but no satisfactory solutions have been found.In previous studies,it is normally assumed that the matrix swelling/shrinking strain can be split between the fracture and the bulk coal and that the splitting coefficient remains unchanged during gas sorption.In this study,we defined the fracture strain as a function of permeability change ratio and back-calculated the fracture strains at different states.In the equilibrium state,the gas pressure is steady within the coal;in the non-equilibrium state,the gas pressure changes with time.For equilibrium states,the back-calculated fracture strains are extremely large and may be physically impossible in some case.For non-equilibrium states,two experiments were conducted:one for a natural coal sample and the other for a reconstructed one.For the fractured coal,the evolution of permeability is primarily controlled by the transition of coal fracture strain or permeability from local matrix swelling effect to global effect.For the reconstituted coal,the evolution of pore strain or permeability is primarily controlled by the global effect.

Water storage changes in North America retrieved from GRACE gravity and GPS data

As global warming continues,the monitoring of changes in terrestrial water storage becomes increasingly important since it plays a critical role in understanding global change and water resource management.In North America as elsewhere in the world,changes in water resources strongly impact agriculture and animal husbandry.From a combination of Gravity Recovery and Climate Experiment（GRACE） gravity and Global Positioning System（GPS） data,it is recently found that water storage from August,2002 to March,2011 recovered after the extreme Canadian Prairies drought between 1999 and 2005.In this paper,we use GRACE monthly gravity data of Release 5 to track the water storage change from August,2002 to June,2014.In Canadian Prairies and the Great Lakes areas,the total water storage is found to have increased during the last decade by a rate of 73.8 ± 14.5 Gt/a,which is larger than that found in the previous study due to the longer time span of GRACE observations used and the reduction of the leakage error.We also find a long term decrease of water storage at a rate of-12.0 ± 4.2 Gt/a in Ungava Peninsula,possibly due to permafrost degradation and less snow accumulation during the winter in the region.In addition,the effect of total mass gain in the surveyed area,on present-day sea level,amounts to-0.18 mm/a,and thus should be taken into account in studies of global sea level change.

数字经济对环境污染的影响及作用机制研究

环境污染是人类面临的重要威胁之一,数字经济有望成为抑制环境污染的新抓手。基于大数据试验区准自然实验,选取中国278个地级市2012—2021年面板数据,采用双重差分模型分析数字经济对环境污染的影响及作用机制。研究发现,数字经济能够显著抑制城市环境污染。该结论经过平行趋势检验、PSM-DID检验、安慰剂检验及排除同期相关政策影响后依然成立。作用机制检验发现,数字经济可通过加强环境规制和提升实质性技术创新两条传导路径抑制环境污染,而策略性技术创新传导路径未获数据支持。异质性分析表明,与基础设施统筹发展试验区相比,跨区域试验区和区域示范试验区所体现的数字经济环境污染抑制效应更强;沿海城市以及数字普惠金融水平较高的城市数字经济对环境污染的抑制效应更强。

Evaluation of Reanalysis Data Based on the Three-dimensional High-density Sounding Data of the Qinghai-Tibet Plateau

Based on the data of the third Qinghai-Tibet Plateau atmospheric science experiment from 2015 to 2017,the applicability of plateau weather systems and meteorological elements of two commonly used reanalysis data(NCEP/NCAR reanalysis data set,and ERA-Interim reanalysis data set)in the plateau was evaluated.Some conclusions are obtained as follows.Compared with EC reanalysis data,NCEP reanalysis data are more consistent with the scientific experimental data.The correlation of geopotential height is above 0.99,followed by temperature;The correlation of specific humidity is the worst.Seen from average deviation,geopotential height and temperature are both lower;for EC,the westerly and southerly winds are both weaker;for NCEP,westerly wind is weaker,while southerly wind is stronger;specific humidity is higher.From the perspective of monthly and seasonal distribution characteristics,the average deviation of geopotential height is larger in spring and summer,and that of temperature is slightly worse in late spring and early summer.In terms of wind field,EC deviation is more obvious in winter,while NCEP deviation is more obvious in late spring and early summer.Seen from spatial distribution,the deviations of geological height and temperature in the north of the plateau are smaller than those in the south of the plateau.For wind field,the westerly wind in the Qaidam Basin is weaker,and the southerly wind in the southern plateau is weaker.In vertical profile,the deviation of geopotential height at high levels is greater than that of low levels.The deviation of temperature and wind field is larger near the ground.The temperature at middle levels and the westerly wind at middle and high levels are smaller,and southerly wind is stronger for NCEP.The establishment of the three sounding stations(Gaize,Shenzha and Shiquanhe)is conducive to the discovery of plateau vortex and plateau shear line in the western plateau.The western plateau vortex and plateau shear line mostly appeared in the flood season.Most plateau weather systems were maintained within 24 h,and mainly appeared and disappeared in situ.The objective recognition rate of EC for plateau weather systems is higher than NCEP,so EC is more conducive to the diagnosis and analysis of evolution characteristics of plateau weather systems.

基于数智技术的新商科实验数据资产管理体系探索与实践

党的二十大首次提出“推进教育数字化”,并明确了教育数字化未来发展的行动纲领。推进高校实验教学数字化体系规划设计,将实验数据资产作为重要生产要素纳入新商科数据资产管理应用建设体系,是落实党的二十大精神、打造数字教育生态的重要举措。管理与经济实验教学中心联合数字经济与政策智能工业和信息化部重点实验室,积极探索基于数智技术的实验数据资产生态体系,围绕实验数据从数据发现、价值开发、价值实现、协同共享等4个环节开展新商科实验数据资产建设,推进实验数据资产管理、协同和共享,提升实验数据应用价值,探索实验数据治理,助力数字经济时代新商科数字化创新人才培养。

Vehicle Off-road Experimental System Development and Verification Based on the Labview

The problems in the vehicle off-road experiment, such as various kinds of expensive instruments and diffi- culty in matching the input and the output signals of the vehicle status which cause useless data acquired. On the basis of considering the test functions and experimental cost, this paper has developed a vehicle off-road experimental system basing on the Labview. This system can complete various kinds of signal acquisition in one experimental sys- tem and automatically restore the data by types. This solves the problem of real time matching between the input and the output signals, making sure that the data won＇t be confused as the experimental increase, so as to level the ex- perimental efficiency and data accuracy. This system has been used to the experiment of some armored vehicles. The analysis of the data has verified the reliability of the system.

戴维孙-革末电子衍射实验数据的一点启示

1927年戴维孙(C.Davisson)和革末(L.H.Germer)的电子衍射实验第一次可争辩地验证实物粒子的波动性。事实上,与德布罗意(de Broglie)假设的理论计算相比,戴维孙-革末的电子衍射实验数据存在着一种明显的系统性偏离。在近百年之后的今天,该偏离或许为当前电子的电磁质量的研究提供一个有价值的启示和实验依据。

压力波发生器的调制与控制方法研究

泥浆压力波发生器通过控制转阀产生压力波信号,是石油钻井和煤矿开采中的重要通信装置。针对压力波信号调制和转阀控制需求:首先提出下边带恒包络平滑相位调制方法,保证信号幅值恒定并降低驱动功率需求;然后,基于自抗扰控制算法设计控制系统,实现转阀位置精准控制,保证压力波信号质量;最后,开发具备力矩加载、参数调试和数据管理等功能的实验测试装置对所提方法进行验证。实验结果表明,所提方法有效实现了压力波信号平滑相位调制和转阀抗干扰控制。所提方法和实验装置具有多学科融合特性,有助于提高学生解决实际复杂工程问题的能力。

大数据综合试验区建设与产业链现代化——影响效应与作用机理

选取2000—2021年中国30个省级面板数据,利用多期DID方法(Time-varying DID),实证检验国家级大数据综合试验区设立对产业链现代化的影响效应、作用机理与重要条件。研究结果表明,国家级大数据综合试验区建设能够推动产业链现代化,从动态效应来看,随着年份推移,试点政策对产业链现代化的促进效果逐渐增强。该结论在经过PSM-DID检验、缩尾处理等一系列稳健性检验后依然成立。机制分析表明,技术进步、产业结构升级和人力资本积累是国家级大数据综合试验区建设赋能产业链现代化的有效路径。核心结论为实现数据要素与产业链现代化深度融合的政策愿景提供了经验证据和决策参考。