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A methodology for laser tool setters calibration and its precise mathematical model

Chinese Journal of Aeronautics 2024年第7期37卷 564-581页

作者： Tao fang Zixi fang Ze Zhong CHEN Zhiyong CHANG School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China Gina Cody School of Engineering and Computer Science Concordia UniversityMontrealQuebec H3G 1M8Canada Changsha Optimum CNC Corporation Changsha 410221China Institute for Aero-engine Smart Assembly of Shaanxi Province Xi’an 710072China

On-machine tool setting is a pivotal approach in achieving intelligent manufacturing,and laser tool setters have become a crucial component of smart machine *** tool setters play a crucial role in precisely measuring the dimensions of cutting tools during the part machining process,focusing on tool length and *** a measuring instrument,the positions of the laser axis of the laser tool setter need to be accurately calibrated before ***,in actual calibration scenarios,traditional calibration methods face challenges due to installation errors in the tool setter and geometric errors in the measuring *** address this issue,this study proposes a novel calibration ***,the calibration mechanism of the laser beam axis is *** on the accurate mathematical model of the laser beam and the measuring rod,and using the polygon clipping algorithm,the mathematical mechanism of the laser tool setter’s work is ***,a novel method is introduced to calculate the compensation distance between the laser beam reference point and the rod bottom center point at each moment during ***,by utilizing the kinematic chain of the tool setter calibration system,a new calibration method is developed to accurately calibrate the position of the laser beam axis in the machine tool coordinate ***,the accuracy of the calibration method is verified through simulation experiments and calibration *** method improves the calibration accuracy of the tool setter,and the mathematical model of the laser tool setter can be extended to the measurement of tools,thereby improving the precision of tool *** research significantly improves the efficient production performance of smart machine tools.

关键词： On-machine tool setting Smart machine tools Mathematical model Calibration method Laser tool sette

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Dietary intake and serum levels of copper and zinc and risk of hepatocellular carcinoma:A matched case-control study

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Chinese Medical Journal 2024年第5期137卷 596-603页

作者： Xiaozhan Liu Yaojun Zhang Dinuerguli Yishake Yan Luo Zhaoyan Liu yuming Chen Huilian Zhu Aiping fang Guangdong Provincial Key Laboratory of Food Nutrition and HealthSchool of Public HealthSun Yat-sen UniversityGuangzhouGuangdong 510080China State Key Laboratory of Oncology in South China Sun Yat-sen University Cancer CenterGuangzhouGuangdong 510060China

Background:Copper and zinc are involved in the development of multiple malignancies;yet,epidemiological evidence on hepatocellular carcinoma(HCC)is *** study aimed to investigate the association between dietary intake and serum levels of copper and zinc with the risk of ***:A total of 434 case-control pairs matched for sex and age(±1 year)were included in this *** with newly diagnosed HCC were from the Guangdong Liver Cancer Cohort(GLCC)study,and healthy controls were from the Guangzhou Nutrition and Health Study(GNHS).A semi-quantitative 79-item food frequency questionnaire(FFQ)was used to assess habitual dietary intakes of copper and *** levels of copper and zinc were measured by using inductively coupled plasma mass *** copper(Cu)/zinc(Zn)ratio was computed by dividing copper levels by zinc *** logistic regression models were performed to calculate the odds ratio(OR)and 95%confidence intervals(CI)for per 1 standard deviation increase(per-SD increase)in copper and zinc ***:Higher dietary intake(OR_(per-SD increase)=0.65,95%CI:0.44,0.96,P_(trend)=0.029)and serum levels of zinc(OR_(per-SD increase)=0.11,95%CI:0.04,0.30,P_(trend)<0.001)were both associated with a lower risk of *** analyses showed that the inverse association was only pronounced in men but not in women(P_(interaction)=0.041 for dietary zinc intake and 0.010 for serum zinc levels).Serum copper levels(OR_(per-SD increase)=2.05,95%CI:1.39,3.03,P_(trend)=0.020)and serum Cu/Zn ratio(OR_(per-SD increase)=6.53,95%CI:2.52,16.92,P_(trend)<0.001)were positively associated with HCC risk,while dietary copper intake and dietary Cu/Zn ratio were not associated with HCC ***:Zinc may be a protective factor for HCC,especially among men,but the effects of copper on HCC risk are not clear.

关键词： Copper Zinc Hepatocellular carcinoma risk Case-control studies Dietary intake Serum

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Triangle-free Graphs with Three Positive Eigenvalues

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Algebra Colloquium 2024年第3期31卷 525-540页

作者： fang Duan School of Mathematical Sciences Xinjiang Normal UniversityUrumqi 830017China

A graph G is called triangle-free if G does not contain any triangle as its induced *** G_(n)be the set of triangle-free graphs of order n each of which has three positive *** this paper,we find 20 specific graphs in G_(n),each of which has nullity no more than 2,and we show that in terms of three graph transformations all the other graphs of G_(n)can be constructed from these 20 specific ***,we completely characterize the triangle-free graphs with exactly three positive eigenvalues.

关键词： positive(negative)inertia index nullity triangle-free graph

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Superior compound coatings prepared by low-temperature vanadium-nitrocarburizing duplex treatment

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Rare Metals 2024年第4期43卷 1828-1835页

作者： Gen Jin fang-fang Xu Xun-Xun Hu Yue Xu School of Chemistry Beihang UniversityBeijing100191China Guobiao(Beijing)Testing and Certification Co. LtdBeijing100088China School of Materials Science and Engineering Beihang UniversityBeijing100191China

Superior compound coatings were prepared on CK45 steel surface by vanadium-nitrocarburizing duplex treatment in low-temperature salt *** this study,the microhardness,the phase constitution and the compositional distribution in the coatings prepared under different conditions were systematically *** results indicated that the reactions among activated vanadium,carbon and nitrogen atoms occurred on the steel surface,leading to the formation of compound coatings composed of outermost and compound *** mechanism for the formation of compound layer as well as the growth kinetics of the layer was also *** the duplex treatment,the wear and corrosion resistances of steel surface were significantly *** was found that the growth kinetics of compound layer obeyed the parabolic law,with the activation energy of 122.82 kJ·moL^(-1).

关键词： Vanadium-nitrocarburizing duplex treatment Compound coatings Microstructure Formation mechanism Growth kinetics

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图像质量评价研究综述——从失真的角度

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中国图象图形学报 2022年第5期27卷 1430-1466页

作者：鄢杰斌方玉明刘学林江西财经大学信息管理学院南昌330032

随着多媒体技术的快速发展及广泛应用,图像质量评价因其在多媒体处理中的重要作用得到越来越多的关注,其作用包括图像数据筛选、算法参数选择与优化等。根据图像质量评价应用时是否需要参考信息,它可分为全参考图像质量评价、半参考图... 详细信息

随着多媒体技术的快速发展及广泛应用,图像质量评价因其在多媒体处理中的重要作用得到越来越多的关注,其作用包括图像数据筛选、算法参数选择与优化等。根据图像质量评价应用时是否需要参考信息,它可分为全参考图像质量评价、半参考图像质量评价和无参考图像质量评价,前两类分别需要全部参考信息和部分参考信息,而第3类不需要参考信息。无论是全参考、半参考还是无参考图像质量评价,图像失真对图像质量评价的影响均较大,主要体现在图像质量评价数据库构建和图像质量评价模型设计两方面。本文从图像失真的角度,主要概述2011—2021年国内外公开发表的图像质量评价模型,涵盖全参考、半参考和无参考模型。根据图像的失真类型,将图像质量评价模型分为针对合成失真的图像质量评价模型、针对真实失真的图像质量评价模型和针对算法相关失真的图像质量评价模型。其中,合成失真是指人工添加噪声,如高斯噪声和模糊失真,通常呈现均匀分布;真实失真是指在图像的获取中,由于环境、拍摄设备或拍摄操作不当等因素所引入的失真类型。相对合成失真,真实失真更为复杂,可能包括一种或多种失真,数据收集难度更大;算法相关失真是指图像处理算法或计算机视觉算法在处理图像时,由于算法本身的缺陷或性能不足等原因而出现在结果图像中的降质,相对合成失真和真实失真,算法相关失真的显著特点是该类型失真呈现非均匀分布。本文介绍现有的图像质量评价数据库,包括图像数据来源和数据库构建细节等;然后重点介绍图像质量评价模型的设计思想。最后总结了介绍的图像质量评价模型,并指出未来可能的发展方向。

关键词：图像质量评价(IQA) 图像处理视觉感知计算机视觉机器学习深度学习

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深度学习时代图像融合技术进展

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中国图象图形学报 2023年第1期28卷 102-117页

作者：左一帆方玉明马柯德江西财经大学信息管理学院南昌330013 香港城市大学计算机学院中国香港999077

为提升真实场景视觉信号的采集质量,往往需要通过多种融合方式获取相应的图像,例如,多聚焦、多曝光、多光谱和多模态等。针对视觉信号采集的以上特性,图像融合技术旨在利用同一场景不同视觉信号的优势,生成单图像信息描述,提升视觉低、... 详细信息

为提升真实场景视觉信号的采集质量,往往需要通过多种融合方式获取相应的图像,例如,多聚焦、多曝光、多光谱和多模态等。针对视觉信号采集的以上特性,图像融合技术旨在利用同一场景不同视觉信号的优势,生成单图像信息描述,提升视觉低、中、高级任务的性能。目前,依托端对端学习强大的特征提取、表征及重构能力,深度学习已成为图像融合研究的主流技术。与传统图像融合技术相比,基于深度学习的图像融合模型性能显著提高。随着深度学习研究的深入,一些新颖的理论和方法也促进了图像融合技术的发展,如生成对抗网络、注意力机制、视觉Transformer和感知损失函数等。为厘清基于深度学习技术的图像融合研究进展,本文首先介绍了图像融合问题建模,并从传统方法视角逐渐向深度学习视角过渡。具体地,从数据集生成、神经网络构造、损失函数设计、模型优化和性能评估等方面总结了基于深度学习的图像融合研究现状。此外,还讨论了选择性图像融合这类衍生问题建模(如基于高分辨率纹理图融合的深度图增强),回顾了一些基于图像融合实现其他视觉任务的代表性工作。最后,根据现有技术的缺陷,提出目前图像融合技术存在的挑战,并对未来发展趋势给出了展望。

关键词：图像融合深度神经网络随机梯度优化(SGD) 图像质量评价深度学习

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Control of Virtual Synchronous Generator for Frequency Regulation Using a Coordinated Self-adaptive Method

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 175-184页

作者： Hongwei fang Zhiwei Yu School of Electrical and Information Engineering and Key Laboratory of Tianjin Electric Power System Simulation and Control Tianjin UniversityTianjin 300072China

Power inverter adopting virtual synchronous generator(VSG)control can provide inertia support for distributed generation ***,it cannot take into account the dynamic regulation characteristics of ***,when the system encounters a sudden change in load or disturbance,the dynamic process of frequency regulation will be greatly *** view of this issue,an improved VSG control strategy based on a coordinated self-adaptive(CSA)method is *** time domain analysis method is used to study the influences of virtual inertia and damping parameter perturbation on the system steady and dynamic ***,in order to make the control strategy suitable for large load changes and suppress frequency variations beyond the limit,the secondary frequency modulation is introduced into the control *** the coordinated adaptive control of virtual inertia,virtual damping and frequency modulation,the dynamic performance of vSG frequency regulation can be obviously *** and experiment results have verified the effectiveness of the proposed CSA control strategy.

关键词： Coordinated self-adaptive method frequency regulation time domain analysis virtual synchronous generator

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《高层建筑岩土工程勘察标准》(JGJ/T72-2017)部分条文探析

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土工基础 2019年第3期33卷 313-319页

作者：方雨明深圳市龙岗地质勘查局广东深圳518172

《高层建筑岩土工程勘察标准》(JGJ/T72-2017)自2018年2月1日起实施,部分条文可能有'错误'或者可能引起误解。为正确理解条文,从以下几个方面对其进行了探究:标准定义的术语是否合理;条文中采用的专业术语的意义是否明确并在同一专业范... 详细信息

《高层建筑岩土工程勘察标准》(JGJ/T72-2017)自2018年2月1日起实施,部分条文可能有'错误'或者可能引起误解。为正确理解条文,从以下几个方面对其进行了探究:标准定义的术语是否合理;条文中采用的专业术语的意义是否明确并在同一专业范围内具有唯一性;条文的内容是否合理;标准的条文是否条理清楚、措辞是否严谨;标准不同的条文对同一事物的规定是否一致;标准与其引用的标准对同一事物的规定是否一致。在此基础上,对这部分的条文重新进行了表述或提出了'修改意见',将有助于标准使用者正确地理解和执行新版标准。

关键词：高层建筑岩土工程勘察标准条文探析

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Microbe-induced gene silencing explores interspecies RNAi and opens up possibilities of crop protection

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Science China(Life Sciences) 2024年第3期67卷 626-628页

作者： Rongxiang fang State Key Laboratory of Plant Genomics Institute of MicrobiologyChinese Academy of Sciencesand National Plant Gene Research CenterBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

In most eukaryotes, small RNA(sRNA)-mediated RNA silencing(or RNA interference, RNAi) is an evolutionarily conserved mechanism that regulates gene expression in a sequence-specific ***, s RNAs are produced by the RNase III enzymes Dicers and then incorporated into Argonaute(AGO) proteins to regulate gene expression by mRNA degradation.

关键词： protection conserved manner

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Electrically tunable liquid crystal coplanar waveguide

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Frontiers of Information Technology & Electronic Engineering 2021年第9期22卷 1270-1276页

作者： Xingye FAN Ruozhou LI Jing YAN yuming fang Ying YU College of Electronic and Optical Engineering&College ofMicroelectronics Nanjing University of Posts andTelecommunicationsNanjing 210023China National and LocalJoint Engineering Laboratory of RF Integration and Micro-AssemblyTechnology Nanjing University of Posts and TelecommunicationsNanjing210023China

A tunable stepped-impedance resonator using liquid crystal is *** resonant frequencies at 3.367 and 7.198 GHz are realized and can be continuously tuned by external applied *** tunable ranges of 52 and 210 MHz have been achieved at a particularly low driving voltage of 14 V,which shows good agreement with the simulation *** voltage-induced hysteresis phenomenon is also *** device also has a low insertion loss of-2.9 and-4 dB for the two resonant frequencies and the return losses are less than-21.5 *** work provides a new protocol to realize a tunable frequency for communication systems.

关键词： Tunable stepped-impedance resonator(SIR) Uquid crystal Coplanar waveguide(CPW)

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