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Numerical Evaluation on the Thermal Performance of the Solar External Cylinder Receiver using Monte Carlo Ray-Tracing Algorithm

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Journal of Thermal Science 2023年第6期32卷 2065-2080页

作者： li yawei ZHOU Hao ZUO Yuhang State Key Laboratory of Clean Energy Utilization Institute for Thermal Power EngineeringZhejiang UniversityHangzhou310027China

The heat receiver is an essential part of the Concentrating Solar Power plant,directly affecting its operation and *** this paper,the Monte Carlo ray-tracing algorithm was introduced to evaluate a 50 MW(e)external cylindrical receiver’s thermal *** radiation heat flux concentrated from the heliostats field and the view factors between grids divided from the tubes were both calculated using Monte Carlo ray-tracing ***,an in-house code was developed and verified,including three modules of the view-factor calculation,thermal performance calculation,and thermal stress *** was also employed to investigate the 50 MW(e)receiver,and the detailed 3D profiles of temperature and thermal stress in the receiver were *** was found that the molten salt was heated from 298℃to 565℃and the tube at the 50 MW(e)receiver’s outlet had a high temperature,while the high thermal stress came out at the receiver’s ***,the over-temperature of the receiver was discussed,and an optimization algorithm was *** tube wall temperature and film temperature at the overheated area matched the safety criteria,and the outlet molten salt temperature still reached 563℃after the optimization process,with only 2℃dropped.

关键词： solar cylinder external receiver Monte Carlo ray tracing algorithm view factor thermal performance and thermal stress over-heating of the receiver

Performance-weighted-voting model:An ensemble machine learning method for cancer type classification using whole-exome sequencing mutation

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Quantitative Biology 2020年第4期8卷 347-358页

作者： yawei li Yuan Luo Department of Preventive Medicine Northwestern UniversityFeinberg School of MedicineChicagoIL 60611USA

Background:With improvements in next-generation DNA sequencing technology,lower cost is needed to collect genetic *** machine learning techniques can be used to help with cancer analysis and ***:We developed an ensemble machine learning system named performance-weighted-voting model for cancer type classification in 6,249 samples across 14 cancer *** ensemble system consists of five weak classifiers(logistic regression,SVM,random forest,XGBoost and neural networks).We first used cross-validation to get the predicted results for the five *** weights of the five weak classifiers can be obtained based on their predictive performance by solving linear regression *** final predicted probability of the performance-weighted-voting model for a cancer type can be determined by the summation of each classifier's weight multiplied by its predicted ***:Using the somatic mutation count of each gene as the input feature,the overall accuracy of the performance-weighted-voting model reached 71.46%,which was significantly higher than the five weak classifiers and two other ensemble models:the hard-voting model and the soft-voting *** addition,by analyzing the predictive pattern of the performance-weighted-voting model,we found that in most cancer types,higher tumor mutational burden can improve overall ***:This study has important clinical significance for identifying the origin of cancer,especially for those where the primary cannot be *** addition,our model presents a good strategy for using ensemble systems for cancer type classification.

关键词： cancer type classification ensemble method performance-weighted-voting model linear regression single-nucleotide polymorphism

Frequency domain based super-resolution method for mixed-resolution multi-view images

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Journal of Systems Engineering and Electronics 2016年第6期27卷 1303-1314页

作者： Zhizhong Fu yawei li Yuan li Lan Ding Keyu Long School of Communication and Information Engineering University of Electronic Science and Technology of ChinaChengdu 611731China The Second Research Institute of Civil Aviation Administration of China Chengdu 610041China

Super-resolution (SR) techniques, which are based on single or multi-frame low-resolution (LR) images, have been extensively investigated in the last two decades. Mixed-resolution multiview video format plays an important role in three-dimensional television (3DTV) coding scheme. Previous work considers multiview or multi-camera images and videos at the same resolution, which performs well under the planar model without or with little projection error among the videos captured by different cameras. In recent years, several researchers have discussed the SR problem in mixed-resolution multi-view video format, where the superresolved image is created using the up-sampled version of the LR image and the high frequency components extracted from the warped image in the adjacent high-resolution (HR) views. Unfortunately, the output HR images suffer from artifacts caused by depth error. To obtain the detailed texture and edge information from the HR image as much as possible, while preserving the structure of the LR image, a novel SR reconstruction algorithm is proposed. The algorithm is composed of three components: the structure term, the detail information term, and the regularization term. The first term preserves the structure similarity of the LR image; the second term extracts detailed information from the adjacent HR image; and the last term ensures the uniqueness of the solution. Experimental results show the effectiveness and robustness of the proposed algorithm, which achieves high performance both subjectively and objectively. © 2016 Beijing Institute of Aerospace Information.

关键词： Cameras Edge detection Frequency domain analysis Image reconstruction Optical resolving power

An image mosaic technique with non-overlapping regions based on microscopic vision in precision assembly

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Nanotechnology and Precision Engineering 2023年第4期6卷 66-74页

作者： yawei li Xiaodong Wang Tao Wang Yi Luo Key Laboratory for Micro/Nano Technology and System of liaoning Province Dalian University of TechnologyDalian 116024China Key Laboratory for Precision and Non-Traditional Machining of Ministry of Education Dalian University of TechnologyDalian 116024China

Microscopic vision has been widely applied in precision *** achieve sufficiently high resolution in measurements for precision assembly when the sizes of the parts involved exceed the field of view of the vision system,an image mosaic technique must be *** this paper,a method for constructing an image mosaic with non-overlapping areas with enhanced efficiency is ***,an image mosaic model for the part is created using a geometric model of the measurement system installed on a X-Y-Z precision stages with high repeatability,and a path for image acquisition is ***,images are captured along the same path for a specified calibration plate,and an entire image is formed based on the given *** measurement results obtained from the specified calibration plate are utilized to identify mosaic errors and apply compensation for the part requiring *** results show that the maximum error is less than 4μm for a camera with pixel equivalent 2.46μm,thereby demonstrating the accuracy of the proposed *** image mosaic technique with non-overlapping regions can simplify image acquisition and reduce the workload involved in constructing an image mosaic.

关键词： Image mosaic Microscopic vision Visual measurement Precision assembly

Microstructural Evolution and Oxidation Resistance of Multi-walled Carbon Nanotubes in the Presence of Silicon Powder at High Temperatures

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Journal of Materials Science & Technology 2012年第7期28卷 599-605页

作者： Ming LUO yawei li Shengli Jin Shaobai Sang Lei Zhao The Key State Laboratory Breeding Base of Refractories and Ceramics Wuhan University of Science and TechnologyWuhan 430081 China

The microstructural evolution and oxidation resistance of multi-walled carbon nanotubes （MWCNTs） by di- rectly heating silicon powder and MWCNTs in a coke bed from 1000 to 1500 ~C are investigated with the aid of X-ray diffraction （XRD）, scanning electron microscopy （SEM）, high resolution transmission electron microscopy （HRTEM） and thermogravimetry-differential scanning calorimetry （TG-DSC）. The results showed that the morphology and microstructure of MWCNTs did not change much after being treated from 1000 ~C to 1200 ~C. An obvious SiC coating was formed on the surface of MWCNTs from 1300 to 1400 ~C. Up to 1500 ~C, nearly all the MWCNTs transformed into SiC nanowires. The oxidation resistance of the treated MWCNTs was improved compared with as-received ones. Non-isothermal kinetics showed that the oxidation activation energy of the treated MWCNTs reached 208 kJ/mol, much higher than 264 k J/tool of as-received ones.

关键词： Multi-walled carbon nanotubes (MWCNTs) Coating SiC nanowires Oxidation resistance Oxidation activation energy

Machine Learning for Lung Cancer Diagnosis,Treatment,and Prognosis

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Genomics, Proteomics & Bioinformatics 2022年第5期20卷 850-866页

作者： yawei li Xin Wu Ping Yang Guoqian Jiang Yuan Luo Department of Preventive Medicine Feinberg School of MedicineNorthwestern UniversityChicagoIL 60611USA Department of Medicine University of Illinois at ChicagoChicagoIL 60612USA Department of Quantitative Health Sciences Mayo ClinicRochesterMN 55905/ScottsdaleAZ 85259USA Department of Artificial Intelligence and Informatics Mayo ClinicRochesterMN 55905USA

The recent development of imaging and sequencing technologies enables systematic advances in the clinical study of lung ***,the human mind is limited in effectively handling and fully utilizing the accumulation of such enormous amounts of *** learningbased approaches play a critical role in integrating and analyzing these large and complex datasets,which have extensively characterized lung cancer through the use of different perspectives from these accrued *** this review,we provide an overview of machine learning-based approaches that strengthen the varying aspects of lung cancer diagnosis and therapy,including early detection,auxiliary diagnosis,prognosis prediction,and immunotherapy ***,we highlight the challenges and opportunities for future applications of machine learning in lung cancer.

关键词： Omics dataset Imaging dataset Feature extraction Prediction Immunotherapy

Experimental Investigation and X-Ray Computed Microtomography Simulation on Thermal Physical Properties of Foundation Materials after Molten Salt Leakage in the Storage Tank

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Journal of Thermal Science 2024年第2期33卷 591-601页

作者： WANG Zhaowen ZHOU Hao LUO Jiawei li yawei FANG Hao liU Tianxiao State Key Laboratory of Clean Energy Utilization Institute for Thermal Power EngineeringZhejiang UniversityHangzhou310027China

This paper studied the thermal physical properties of foundation materials in the molten salt tank of thermal energy storage system after molten salt leakage by Transient plane source experiment and X-ray computed microtomography simulation *** microstructure,thermal properties and pressure resistance with different particle diameters were *** measured heat conductivities from Transient plane source experiment for three cases are 0.49 W/(m·K),0.48 W/(m·K),and 0.51 W/(m·K),and the porosity is 30.1%,30.7%,and 31.2% *** heat conductivity simulating results of three cases are 0.471 W/(m·K),0.482W/(m·K),and 0.513 W/(m·K).The ratio of difference between the results of simulation and Transient plane source measurement is as low as 1.2%,verifying the reliability of experimental and simulation results to a certain *** with the heat conductivity of 0.097-0.129 W/(m·K) and porosity of 71.6%-78.9% without leaking salt,the porosity is reduced by more than 50% while the heat conductivity increased by 4 to 5 times after molten salt *** significant increase in heat conductivity has a great impact on security operation,structure design,and modeling of the tank foundation for solar power plants.

关键词： heat conductivity X-ray computed microtomography foundation materials three-phase threshold algorithm molten salt leakage

Enhanced thermal shock and oxidation resistance of Si_2BC_3N ceramics through MWCNTs incorporation

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Journal of Advanced Ceramics 2018年第3期7卷 276-288页

作者： Ning liAO Dechang JIA Zhihua YANG Yu ZHOU yawei li Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of Technology Key Laboratory of Advanced Structure-Function Integrated Materials and Green Manufacturing Technology Ministry of Industry and Information Technology State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and Technology National–provincial Joint Engineering Research Center of High Temperature Materials and lining Technology

Multi-walled carbon nanotubes(MWCNTs)reinforced Si_2BC_3N ceramics were prepared through mechanical alloying(MA)and following spark plasma sintering(SPS).The thermal shock resistance of Si_2BC_3N ceramics was evaluated comparatively through ice water quenching test and theoretical ***,the oxidation resistance of MWCNTs incorporated Si_2BC_3N ceramics was evaluated under high *** results show that the calculated parameters such as the critical thermal shock temperature(R)and the thermal stresses resistance(R_(st)),as well as the toughness(R"")are improved with addition of 1 vol%*** addition,the crack propagation resistance of 1 vol%MWCNTs incorporated Si_2BC_3N ceramics is obviously improved through generating more tortuous crack propagation paths attributing to the"crack bridging","pull-out",and"crack deflection"mechanisms of ***,the residual strengths of 1 vol%MWCNTs containing specimens remained the highest after the thermal shock ***,the present work also reveals that the oxidation resistance is more sensitive to relative density than MWCNTs addition.

关键词： Si2BC3N ceramics MWCNTs thermal shock resistance oxidation resistance

Regulation of Pore Structure and Hightemperature Fracture Behavior of CACbonded Alumina-Spinel Castables Based on Hydration Design

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China's Refractories 2024年第3期33卷 22-29页

作者： Wenjing liU Ning liAO yawei li The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081China National-provincial Joint Engineering Research Center of High Temperature Materials and lining Technology Wuhan 430081China Joint International Research Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081China

The lamellar hydrates of CAC were designed with the introduction of nano CaCO_(3)or Mg-Al hydrotalcite(M-A-H),and the effects on the green strength,pore structures,and high-temperature fracture behavior of alumina-spinel castables were *** results show that nano CaCO_(3)or M-A-H stimulates rapidly the hydration of CAC and the formation of lamellar C_(4)AcH_(11)or coexistence of C_(2)AH_(8)and C_(4)AcH_(11)at 25℃.The formation of lamellar hydrates can contribute to a more complicated pore structure,especially in the range of 400-2000 ***,the incorporation of well-distributed CaO or MgO sources from nano CaCO_(3)or M-A-H also regulates the distribution of CA_(6)and spinel(pre-formed and in-situ).Consequently,the optimized microstructure and complicated pore structure can induce the deflection and bridging of cracks,thus facilitating the consumption of fracture energy and enhancing the resistance to thermal stress damage.

关键词： alumina-spinel castables lamellar hydrates pore structure high-temperature wedge splitting test fracture behavior