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Causal temporal graph attention network for fault diagnosis of chemical processes

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Chinese Journal of Chemical Engineering 2024年第6期70卷 20-32页

作者： jiaojiao Luo Zhehao jin Heping jin Qian Li xu ji Yiyang Dai School of Chemical Engineering Sichuan UniversityChengdu 610065China China Three Gorges Corporation Beijing 100038China

Fault detection and diagnosis(FDD)plays a significant role in ensuring the safety and stability of chemical *** the development of artificial intelligence(AI)and big data technologies,data-driven approaches with excellent performance are widely used for FDD in chemical ***,improved predictive accuracy has often been achieved through increased model complexity,which turns models into black-box methods and causes uncertainty regarding their *** this study,a causal temporal graph attention network(CTGAN)is proposed for fault diagnosis of chemical processes.A chemical causal graph is built by causal inference to represent the propagation path of *** attention mechanism and chemical causal graph were combined to help us notice the key variables relating to fault *** in the Tennessee Eastman(TE)process and the green ammonia(GA)process showed that CTGAN achieved high performance and good explainability.

关键词： Chemical processes Safety Fault diagnosis Causal discovery Attention mechanism Explainability

Laboratory evaluation of high-friction thin overlays for pavement preservation

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Frontiers of Structural and Civil Engineering 2024年第6期18卷 936-948页

作者： Ouming xu Rentao xu Lintong jin School of Highway Chang’an UniversityXi’an 710064China School of Materials Science and Engineering Chang’an UniversityXi’an 710061China

Traditional asphalt concrete(AC)and stone matrix asphalt(SMA),which are used as thin asphalt overlays,are common maintenance strategies to enhancing ride quality,skid resistance,and ***,several studies have used a novel asphalt mixture known as a high-friction thin overlay(HFTO)to improve surface ***,it remains uncertain whether the laboratory properties of HFTO differ significantly from those of conventional *** study aims to evaluate the laboratory properties of HFTO mixtures and compare them with those of AC and *** mixtures with nominal maximum size of 9.5 mm were produced in the laboratory,and performance tests were conducted,including wheel tracking test,low temperature flexural creep test,moisture susceptibility test,Cantabro Abrasion Test,Marshall Test,sand patch test,British pendulum test,and indoor tire-rollingdown *** results showed that the HFTO exhibited a lower tire/pavement noise than the AC and ***,HFTO had superior high-temperature stability,larger macro texture,and higher skid resistance in comparison to those of AC,but lower than those of ***,HFTO mixtures may be considered a suitable replacement for traditional AC mixtures in regions where skid resistance and noise reduction are concerns.

关键词： road engineering pavement maintenance high friction thin overlay performance skid resistance tire/pavement noise

Impact of smoking status and pathologic type on epidermal growth factor receptor mutations in lung cancer

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Chinese Medical Journal 2011年第16期124卷 2457-2460页

作者： HUANG Yi-sheng YANG jin-ji ZHANG xu-chao YANG xue-ning HUANG Yu-juan xu Chong-rui ZHOU Qing WANG Zhen SU jian WU Yi-long Guangdong Lung Cancer Institute Guangdong General Hospital &Guangdong Academy of Medical Sciences GuangzhouGuangdong 510080 China

Background Epidermal growth factor receptor （EGFR） responsive to the treatment with tyrosine kinase inhibitors. large series of lung carcinomas. mutations in lung carcinomas can make the disease more We aimed to evaluate the prevalence of EGFR mutations in a Methods We examined 1195 consecutive lung cancer patients for EGFR mutations in exons 18, 19, and 21 using direct sequencing of polymerase chain reaction products. A detailed smoking history was obtained. Patients were categorized as never smokers （〈100 lifetime cigarettes）, former smokers （quit 〉1 year ago）, or current smokers （quit 〈1 year ago）. Results There were EGFR mutations in 9 （4.5%） of 201 squamous carcinomas, in 1 （2%） of 50 large cell carcinomas, and in 1 （2.3%） of 44 small cell carcinomas that were investigated. Three hundred and twenty-seven mutations were found in the series of 858 adenocarcinomas （38.1%）. Among 858 lung adenocarcinomas, we detected EGFR mutations in 250 （48.6%） of 514 never smokers, 39 （33.9%） of 115 former smokers, and 38 （16.6%） of 229 current smokers. Significantly fewer EGFR mutations were found in people who smoked for more than 15 pack-years （P=-0.0002） or stopped smoking less than 15 years ago （P=0.033） compared with individuals who never smoked. Conclusions Adenocarcinoma is the most frequent EGFR mutation pathologic type in lung cancer. The likelihood of EGFR mutations in exons 18, 19 and 21 decreases as the number of pack-years increases. Mutations were less common in people who smoked for more than 15 pack-years or who stopped smoking cigarettes less than 15 years ago. These data can assist clinicians in assessing the likelihood of exons 18, 19, or 21 EGFR mutations in Chinese patients with lung cancer when mutational analysis is not feasible.

关键词： lung neoplasms smoking pathologic type receptor, epidermal growth factor mutation

Soft coarse-grained particle model for particle-fluid systems

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Particuology 2024年第1期84卷 178-193页

作者： Yanhao Ye ji xu Wei Ge State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing100049China Innovation Academy for Green Manufacture Chinese Academy of SciencesBeijing100190China

By modeling a group of neighboring real particles as a single coarse-grained particle(CGP),discrete particle method(DPM)is now capable of simulating industrial-scale particle-fluid ***,a systematic approach to determine the CGP properties and develop their interaction models is still lacking,which casts uncertainty on the predictivity of the *** this study,collisions between predefined particle groups are analyzed to construct kernel functions for modeling the CGPs and then the model parameters are determined by equating the statistical properties of the CGPs and the real particles in the physical process *** approach is implemented for homogeneous cooling of granular gas,then demonstrated effective in simulating experimental fluidized beds.

关键词： Coarse-grain(CG) Discrete particle method(DPM) Fluidized bed Multi-scale simulation

Gas–solid reactor optimization based on EMMS-DPM simulation and machine learning

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Particuology 2024年第6期89卷 131-143页

作者： Haolei Zhang Aiqi Zhu ji xu Wei Ge State Key Laboratory of Mesoscience and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China Innovation Academy for Green Manufacture Chinese Academy of SciencesBeijing 100190China

Design,scaling-up,and optimization of industrial reactors mainly depend on step-by-step experiments and engineering experience,which is usually time-consuming,high cost,and high *** numerical simulation can reproduce high resolution details of hydrodynamics,thermal transfer,and reaction process in reactors,it is still challenging for industrial reactors due to huge computational *** this study,by combining the numerical simulation and artificial intelligence(AI)technology of machine learning(ML),a method is proposed to efficiently predict and optimize the performance of industrial reactors.A gas–solid fluidization reactor for the methanol to olefins process is taken as an example.1500 cases under different conditions are simulated by the coarse-grain discrete particle method based on the Energy-Minimization Multi-Scale model,and thus,the reactor performance data set is *** develop an efficient reactor performance prediction model influenced by multiple factors,the ML method is established including the ensemble learning strategy and automatic hyperparameter optimization technique,which has better performance than the methods based on the artificial neural ***,the operating conditions for highest yield of ethylene and propylene or lowest pressure drop are searched with the particle swarm optimization algorithm due to its strength to solve non-linear optimization *** show that decreasing the methanol inflow rate and increasing the catalyst inventory can maximize the yield,while decreasing methanol the inflow rate and reducing the catalyst inventory can minimize the pressure *** two objectives are thus conflicting,and the practical operations need to be compromised under different circumstance.

关键词： Discrete particle method Artificial intelligence Machine learning Particle swarm optimization Industrial reactor optimization

3D coarse-grained DPM simulation of the MIP reaction-regeneration loop

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Particuology 2024年第6期89卷 57-66页

作者： Yanhao Ye Shuai Zhang ji xu Wei Ge State Key Laboratory of Mesoscience and Engineering(formerly State Key Laboratory of Multiphase Complex Systems) Institute of Process EngineeringChinese Academy of SciencesBeijing100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing100049China

The reactor-regenerator loop is the core facility of the maximizing iso-paraffin(MIP)*** the discrete particle method(DPM)simulation can provide detailed information at the particle scale,it has been unable to simulate such a complex loop system due to limitations of coarse-grained(CG)models,computing software,and *** this study,a newly proposed soft-shell CG-DPM model with a CG ratio of up to 800 is used to simulate a 3.5 Mt/a industrial-scale MIP reactor-regenerator *** solid fraction distribution obtained is found to agree well with in-situ *** properties including the distribution of solid fraction,gas and solid velocity,standard derivation of solid fraction with time,temporal distribution of the flow field,and particle residence time distribution are measured in the simulation,which are meaningful to better design and operate such systems in the future.

关键词： Discrete particle method Coarse-grain Maximizing iso-paraffins Full-loop Reaction-regeneration system

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

Modeling and Validation of Diamagnetic Rotor Levitated by Permanent Magnetics

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 224-235页

作者： Yuanping xu Yue Zhang jin Zhou Chaowu jin College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

As an innovative,low-power consuming,and low-stiffness suspension approach,the diamagnetic levitation technique has attracted considerable interest because of its potential applicability in miniaturized mechanical *** foundation of a diamagnetic levitation system is mathematical modeling,which is essential for operating performance optimization and stability ***,few studies on systematic mathematical modeling have been *** this study,a systematic mathematical model for a disc-shaped diamagnetically levitated rotor on a permanent magnet array is *** on the proposed model,the magnetic field distribution characteristics,diamagnetic levitation force characteristics(i.e.,levitation height and stiffness),and optimized theoretical conditions for realizing stable levitation are *** are conducted to verify the feasibility of the proposed mathematical *** predictions and experimental results indicate that increasing the levitation height enlarges the stable ***,with a further increase in the rotor radius,the stable regions of the rotor gradually diminish and even ***,when the levitation height is fixed,a moderate rotor radius permits stable *** study proposes a mathematical modeling method for a diamagnetic levitation system that has potential applications in miniaturized mechanical systems.

关键词： Diamagnetic levitation Magnetic levitation Rotor Modeling Validation Stability

Flexible capacitive pressure sensor based on interdigital electrodes with porous microneedle arrays for physiological signal monitoring

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Nanotechnology and Precision Engineering 2024年第1期7卷 18-31页

作者： jiahui xu Minghao Wang Minyi jin Siyan Shang Chuner Ni Yili Hu xun Sun Jun xu Bowen ji Le Li Yuhua Cheng Gaofeng Wang School of Electronics&Information MOE Engineering Research Center of Smart Microsensors and MicrosystemsHangzhou Dianzi UniversityHangzhou 310018China Wenzhou Institute of Hangzhou Dianzi University Wenzhou 310018China Key Laboratory of Intelligent Operation and Maintenance Technology&Equipment for Urban Rail Transit of Zhejiang Province College of EngineeringInstitute of Precision Machinery and Smart StructureZhejiang Normal UniversityJinhua 321004China Institute of Guizhou Aerospace Measuring and Testing Technology Guiyang 550009China Unmanned System Research Institute Northwestern Polytechnical UniversityXi’an 710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518057China

Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and ***,their relatively low sensitivity,linearity,and stability have hindered their large-scale commercial ***,aﬂexible capacitive pressure sensor based on an interdigital electrode structure with two porous microneedle arrays(MNAs)is *** porous substrate that constitutes the MNA is a mixed product of polydimethylsiloxane and *** to its porous and interdigital structure,the maximum sensitivity(0.07 kPa-1)of a porous MNA-based pressure sensor was found to be seven times higher than that of an imporous MNA pressure sensor,and it was much greater than that of aﬂat pressure sensor without a porous MNA ***-element analysis showed that the interdigital MNA structure can greatly increase the strain and improve the sensitivity of the *** addition,the porous MNA-based pressure sensor was found to have good stability over 1500 loading cycles as a result of its bilayer parylene-enhanced conductive electrode *** importantly,it was found that the sensor could accurately monitor the motion of aﬁnger,wrist joint,arm,face,abdomen,eye,and Adam’s ***,preliminary semantic recognition was achieved by monitoring the movement of the Adam’s ***,multiple pressure sensors were integrated into a 33 array to detect a spatial pressure distribu-×*** to the sensors reported in previous works,the interdigital electrode structure presented in this work improves sensitivity and stability by modifying the electrode layer rather than the dielectric layer.

关键词： Capacitive pressure sensor Microneedle array Porous PDMS Interdigital electrode