检索结果-内蒙古大学图书馆

IEEE Advanced Information Management,Communicates,Electronic and Automation control Conference (IMCEC)

作者： Xuejing Li Shanghai Institute of Measurement And Testing Technology. Shanghai Key Laboratory of On-line Testing and Control Technology Shanghai China

ISBN: (纸本)9781665479691

Electromagnetic flowmeter(EMFM) is widely used in industrial field and single-phase flow measurement because of its excellent accuracy and stability. In the past decades, Multiphase flow measurement is widely used in petroleum, power, chemical, metallurgical and pharmaceutical fields. In recent years, The study of solid-liquid two-phase flow has become one of the hot topics. The traditional EMFM has many drawbacks in measuring multiphase flow. In terms of sensors, the weight function theory is extended. And aiming at the limitation that the traditional electromagnetic flow sensor needs symmetrical fluid distribution, a multi-electrode non-insulated tube wall electromagnetic flow sensor is designed. In terms of converters, The characteristics of the measured signal are analyzed comprehensively, and the compensation circuit is designed, and the signal amplification circuit is optimized. n the solid-liquid two-phase flow experiment, the theory of extended weight function is verified, and the accuracy and reliability of the designed electromagnetic flowmeter are verified. It provides a feasible way to solve the problem of asymmetric single-phase flow measurement widely existing in the industrial field.

关键词： Weight measurement Fluid flow measurement Power measurement Sensor phenomena and characterization Reliability theory Reconstruction algorithms Reliability engineering

来源：评论

学校读者我要写书评

暂无评论

Research on the Theoretical Steady-State Error of Direct Current Comparator 15

Research on the Theoretical Steady-State Error of Direct Cur...

引用

15th IEEE International Conference on Electronic Measurement and Instruments, ICEMI 2021

作者： Zhou, Liren Zhu, Li Geng, Ji Yi, Qin Yang, Pan Shanghai Institute of Measurement and Testing Technology Shanghai Key Laboratory of Online Testing and Control Technology Shanghai China

ISBN: (纸本)9781665444910

In virtue of modern control theory, combining with the analysis of structure and principle of direct current comparator (DCC), relative error formula of direct current ratio was derived to theoretically analyze the steady state value. Resolve each part of transfer function and then compound the closed-loop transfer function. Employ Nyquist stability criterion to judge the system stability;establish the closed-loop transfer characteristic simulation model;take unit ampere turn value as example and the simulation result was analyzed. The results showed that the secondary side fast tracked the primary side signal and output signal smoothly, without obvious transition appearance such as overshoot and oscillation, according with the principle of DCC. The steady-state error of direct current ratio is 2.5×10-8, consisting with the derived theoretical value, meeting the expected design requirements. © 2021 IEEE.

关键词： Errors

来源：评论

学校读者我要写书评

暂无评论

Calibration Study on Noise Figure Measurement with Precision Attenuator Method

Calibration Study on Noise Figure Measurement with Precision...

引用

International Conference on Integrated Circuits and Microsystems (ICICM)

作者： Wan YiBin Teng Yulong Hang Yuhui Shanghai Institute of Measurement and Testing Technology Shanghai Key Laboratory of On-line measurement and control technology ShangHai China

ISBN: (纸本)9781665460583

The new improved approach for noise Figure are introduced in terms of the signal analysis and two terminal theory. Compared with the traditional method, it is convenient to improve the mismatch problem and reflection effects of NF analyzer over a wide range of frequency. Firstly, it’s revealed that the precision attenuators have the significant advantage of low VSWR and wide bandwidth. Furthermore, the appropriate calibration method provides the suitable formulation for the measurement accuracy and the minimize mismatch uncertainty. Eventually, it’s shown that the evaluation of uncertainty measurement is proposed.

关键词： Microwave measurement Noise figure Attenuators Uncertainty Measurement uncertainty Microwave theory and techniques Reflection

来源：评论

学校读者我要写书评

暂无评论

Power Uncertainty Evaluation of Microwave Digestion System based on Monte-Carlo Method 5

Power Uncertainty Evaluation of Microwave Digestion System b...

引用

5th IEEE Advanced Information technology, Electronic and Automation control Conference, IAEAC 2021

作者： Xiao, Tianlei Wang, Shuhui Xiong, Zhichun Shanghai Institute of Measurement and Testing Technology Shanghai China Key Laboratory of Online Testing and Control Technology of Shanghai Shanghai China

ISBN: (纸本)9781728180281

The article implemented an uncertainty evaluation method for output power of microwave digestion system, based on the adaptive Monte Carlo method and the correlation of inputs. The result is compared with that obtained by GUM method. By using Kolmogorov-Smirnov and Normal probability method, the probability distribution of the output has deviated from normal distribution in a certain interval. The Result of GUM method is not validated, and MCM method is proved to be faster and more efficient in the case of complex models and correlative cases. © 2021 IEEE.

关键词： Monte Carlo methods

来源：评论

学校读者我要写书评

暂无评论

Risk assessment of Bacillus cereus in lettuce grown in open-feld and greenhouse farming systems in China:A comparative study

引用

Food Quality and Safety 2024年第2期8卷 268-277页

作者： Yang Qu ShenghaoYu Haotian Gu WenWang WenboWang Zhaoying He Hong Shan Min Gao Xin Zhao ChaoWei TingtingTao Guanghua Zhao Changyan Zhou Yujuan Suo Laboratory of Quality and Safety Risk Assessment for Agro-Products of Ministry of Agriculture and Rural Affairs Institute for Agro-Food Standards and Testing TechnologyShanghai Academy of Agricultural SciencesShanghaiChina Information Application Research Center of Shanghai Municipal Administration for Market Regulation ShanghaiChina Eco-environmental Protection Research Institute Shanghai Academy of Agricultural SciencesShanghaiChina MOA Laboratory of Quality&Safety Risk Assessment for Agro-products(Hangzhou) Institute of Agro-Product Safety and NutritionZhejiang Academy of Agricultural SciencesHangzhouChina Laboratory of Quality and Safety Risk Assessment for Agro-Products of Ministry of Agriculture and Rural Affairs Institute of Agricultural Standards and Testing Technology for Agri-ProductsShandong Academy of Agricultural SciencesJinanChina Institute of Quality Standard and Testing Technology Beijing Academy of Agriculture and Forestry SciencesBeijingChina Quality and Safety Institute of Agricultural Products Heilongjiang Academy of Agricultural SciencesHarbinChina Institute of Food Science and Technology Chinese Academy of Agricultural SciencesBeijingChina Institute of Germplasm Resources and Biotechnology Tianjin Academy of Agricultural SciencesTianjinChina Laboratory of Quality and Safety Risk Assessment for Agro-Products of Ministry of Agriculture and Rural Affairs Institute of Quality Standard and Testing Technology for Agro-Products of Sichuan Academy of Agricultural SciencesChengduChina Ministry of Science and Technology/Key Laboratory for Control Technology and Standard for Agro-product Safety and Quality Institute of Food Safety and NutritionJiangsu Academy of Agricultural SciencesNanjingChina Research Institute of Agricultural Quality Standards and Testing Techniques Henan Academy and Agricultural SciencesZhengzhouChina

Objectives:Bacillus cereus isolates from vegetables can cause diarrheal syndrome food ***,the most highly consumed readyto-eat vegetable,poses a signifcant risk of *** ***,*** monitoring and evaluation during cultivation are essential for preventing foodborne illnesses caused by this food-pathogen ***,the impact of different cultivation practices on *** contamination in lettuce currently remains ***,a validity indicator for the experimental models cannot be effectively validated under feld *** and Methods:Herein,we assessed the risk of *** exposure using lettuce grown under two different cultivation farming systems in China(open-feld versus greenhouse)using a quantitative microbial risk assessment ***’s mean comparison method and kernel density estimation frequency distribution statistics were used for model validation using environmental samples and ***:The mean concentration of *** in open-feld-grown lettuce was signifcantly higher than that in greenhouse-grown lettuce(P<0.05).No signifcant differences were observed between measured,formula-calculated,and risk assessment values in environmental samples or lettuce(P>0.05),verifying the accuracy of the risk ***:Soil solarization,complete manure treatment,usage of mulch flms,and irrigation water quality should be considered in agricultural practices to control *** concentrations in ***,we found that *** was more abundant in open-feld-grown lettuce,and we provide a risk evaluation framework that can guide farmers and policy-makers to control *** contamination in farm-to-fork lettuce chains in China.

关键词： Diarrheal syndrome food poisoning ready-to-eat vegetable greenhouse microbial risk assessment

来源：评论

学校读者我要写书评

暂无评论

Research on the Influence of Non-Conductor on the Weight Function of Electromagnetic Flowmeter

Research on the Influence of Non-Conductor on the Weight Fun...

引用

2021 Asia-Pacific Conference on Image Processing, Electronics and Computers, IPEC 2021

作者： Li, Xuejing Sun, Lijun Shanghai Institute of Measurement and Testing Technology Shanghai201203 China Shanghai Key Laboratory of On-line Testing and Control Technology Shanghai201203 China School of Electrical and Information Engineering Tianjin University Tianjin300072 China

The demand for multiphase flow measurement is widespread in petrochemical and other fields. Due to its small size, easy maintenance, and no moving parts, electromagnetic flowmeters are widely used in single fluid measurement. With the increasing application of traditional electromagnetic flowmeters in petrochemical and other fields, the problems of traditional electromagnetic flowmeters in multiphase flow measurement applications have been discovered. How to optimize the structure of the electromagnetic flowmeter and how to improve the measurement accuracy has become a new research focus. On the basis of a large number of literature studies, this research is based on the finite element method, and systematically studies the influence of multiphase flow on the weight function of electromagnetic flowmeters. Firstly, modeling the existence of non-conductive objects in the electromagnetic flowmeter. Secondly, analyze the weight function characteristics of the non-conductive objects on the electromagnetic flowmeter from two angles of different radii and different positions. The conclusions of this study can provide a certain reference basis for the electromagnetic flowmeter in the measurement of multiphase flow. © Published under licence by IOP Publishing Ltd.

关键词： Petrochemicals

来源：评论

学校读者我要写书评

暂无评论

Automatic measurement and calibration of DC current ratio error 8

Automatic measurement and calibration of DC current ratio er...

引用

8th International Symposium on Test Automation and Instrumentation, ISTAI 2020

作者： Zhou, Liren Pan, Yang Lai, Lei Feng, Jian Zhan, Guozhong Shanghai Key Laboratory of On-line Testing and Control Technology Shanghai Institute of Measurement and Testing Technology Shanghai China

ISBN: (纸本)9781839535635

DC current ratio error is an essential measurement performance of DC current ratio instrument, for example, DC current comparator, DC current transformer and DC current sensor. Error determination contributes to the instrument rational use. Based on the principle of secondary differential current measurement, self-calibration method, equal-ratio calibration method and stage-connection equal-ratio calibration method were put forward according to the characteristics of different calibrated instruments. Then, the actual value and error of DC current ratio were available. Meanwhile, circuit diagrams, calibration process and examples were provided;measurement uncertainty was evaluated. The result shows that the proposed methods meet the calibration requirements of DC current ratio instruments;the expanded uncertainty for the 1 A: 1 A~1000 A: 0.5 A ratio is 1.7×10-8~8.4×10-6. The automatic measurement program can effectively improve the work efficiency. © 2020 Institution of Engineering and technology. All rights reserved.

关键词： Calibration

来源：评论

学校读者我要写书评

暂无评论

Real-Time Checks for Radiated Emission Measurement System

Real-Time Checks for Radiated Emission Measurement System

引用

International Conference on Electronics technology (ICET)

作者： Jinlong Li Wenhui Zhao Shanyi Jin EMC Laboratory Fundamental Performance Test Center Shanghai Key Laboratory of Online Test and Control Technology Shanghai Institute of Measurement and Testing Technology Shanghai China

In radiation emission measurement, it is necessary to switch different types of measuring antennas or adjust the polarizations of the antennas. Therefore, there is a large risk of measurement data errors in the radiation emission measurement system. However, the current intermediate validation method used for the measurement system is time-consuming and not suitable for frequently checking the system compliance. In this paper, a real-time check method for radiated emission measurement system is proposed to achieve real-time validation of the measurement system during the measurement process. Meanwhile, the influences of the reference signals and electromagnetic wave reflections from the multi-frequency reference source device on measured data are avoided. The accuracy and reliability of the measured data can be ensured.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Carbendazim residue in plant-based foods in China:Consecutive surveys from 2011 to 2020

引用

Environmental Science and Ecotechnology 2024年第1期17卷 109-118页

作者： Dou Wang Guiling Yang Xiao Yun Ting Luo Hao Guo Liying Pan Wei Du Yanhua Wang Qiang Wang Pu Wang Qinghua Zhang Yun Li Nan Lin State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products Laboratory(Hangzhou)for Risk Assessment of Agricultural Products of Ministry of AgricultureInstitute of Agro-product Safety and NutritionZhejiang Academy of Agricultural SciencesHangzhou310021ZhejiangChina College of Urban and Environmental Sciences Peking UniversityBeijing100871China Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control Faculty of Environmental Science&EngineeringKunming University of Science&TechnologyKunming650500China Hubei Key Laboratory of Industrial Fume and Dust Pollution Control School of Environment and HealthJianghan UniversityWuhan430056China State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing100085China Key Laboratory of Agro-Product Quality and Safety of Ministry of Agriculture Institute of Quality Standards and Testing Technology for Agro-ProductsChinese Academy of Agricultural SciencesBeijing100081China Department of Environmental Health School of Public HealthShanghai Jiao Tong UniversityShanghai200025China

Carbendazim,a widely used fungicide in China,has been found to have reproductive toxicity and mutagenic ***,information on the spatial-temporal variations of carbendazim residues in food in China is ***,we investigated the presence of carbendazim in China's plant-based foods from 2011 to 2020,evaluated the spatial-temporal characteristics,and assessed the associated exposure risks in the Chinese *** results revealed a high detection frequency of carbendazim in fruits(26.4%)and high concentrations in vegetables(~110 mg kg^(-1)),indicating widespread misuse of the *** acute risks of consuming certain vegetables and cereals exceeded the recommended limits by up to 12 and 5 times,*** there has been a decline in carbendazim residue levels in food since the implementation of the Chinese government's action plan for zero growth of pesticide use in 2015,some provinces still exhibited high levels of carbendazim in multiple food categories,which were positively correlated with annual pesticide *** highlight that carbendazim contamination reflects the broader issue of pesticide use in *** emphasizes the need for committed and targeted national policies to reduce carbendazim residues in food and suggests that such measures could also regulate the use of other pesticides,given that pesticide abuse in China is not limited to specific *** call for the re-evaluation of maximum residue limits of carbendazim,particularly in highly consumed foods such as cereals.

关键词： Carbendazim Plant-based foods China Spatial-temporal variations Exposure and risk assessment

来源：评论

学校读者我要写书评

暂无评论

Large jitter amplitude calibration of SDH transmission analyzer by wide band FM method 8

Large jitter amplitude calibration of SDH transmission analy...

引用

8th International Symposium on Test Automation and Instrumentation, ISTAI 2020

作者： Zhan, Zhiqiang Yu, Lei Wang, Yunling Shanghai Institute of Measurement and Testing Technology Shanghai China Shanghai Key Laboratory of On-line Testing and Control Technology Shanghai China

ISBN: (纸本)9781839535635

Jitter is a very important parameter in wired digital communication. It is usually measured by SDH transmission analyzer. When the jitter of SDH transmission analyzer is calibrated, the Bessel function ratio method is used. However, the method is not suitable for large jitter amplitude output from SDH transmission analyzer such as 50UIpp above. This paper introduces the wide-band frequency modulation method to calibrate the jitter amplitude of SDH analyzer, and the uncertainty evaluation results are given at the end of this paper. © 2020 Institution of Engineering and technology. All rights reserved.

关键词： Calibration

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：