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Numerical investigation on the caving mechanism with different standard deviations of top coal block size in lTCC

International Journal of Mining Science and Technology 2020年第5期30卷 583-591页

作者： Jiachen Wang Weijie Wei Jinwang Zhang Brijes Mishra ang li State Key laboratory Coal Resources and Safe Mining China University of Mining and Technology-BeijingBeijing 100083China School of Energy and Mining Engineering China University of Mining and Technology-BeijingBeijing 100083China Coal Industry Engineering Research Center of Top-coal Caving Mining Beijing 100083China Department of Mining Engineering West Virginia UniversityMorgantownWV 26505USA

The size distribution of the broken top coal blocks is an important factor,affecting the recovery ratio and the efficiency of drawing top coal in longwall top coal caving(lTCC)mining *** standard deviation of top coal block size(dt)is one of the main parameters to reflect the size distribution of top *** find the effect of dt on the caving mechanism,this study simulates experiments with 9 different dt by using discrete element software *** dt is divided into two stages:uniform distribution stage(UDS)whose dt is less than 0.1(Schemes 1–5),and nonuniform distribution stage(NDS)whose dt is more than 0.1(Schemes 6–9).This research mainly investigates the variation of recovery ratio,drawing body shape,boundary of top coal,and contact force between particles in the two stages,*** results showed that with the increasing dt,the recovery ratio of the panel increases first and then decreases in *** is the largest in Scheme 3,which mainly increases the drawing volume at the side of starting drawing ***,the recovery ratio decreases first and then increases quickly in NDS,and it is the largest in Scheme 9,where the drawing volume at the side of finishing drawing end are relatively *** UDS,the major size of top coal is basically medium,while in NDS,the size varies from medium to small,and then to large,with a distinct difference in shape and volume of the drawing *** the major size of top coal is medium and small,the cross-section width of the initial boundary of top coal at each height is relatively ***,when the top coal size is large,the initial boundary of top coal has a larger opening range,the rotating angle of lower boundary is relatively small in the normal drawing stage,which is conducive to the development of drawing body and reduces the residual top coal,and the maximum particle velocity and the particles movement angle are both *** study lays a foundation for the prediction of recovery ratio,and sug

关键词： longwall top coal caving mining Standard deviation of top coal size Recovery ratio Drawing body Boundary of top coal Contact force

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Modeling and flapping vibration suppression of a novel tailless flapping wing micro air vehicle

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Chinese Journal of Aeronautics 2022年第3期35卷 309-328页

作者： Siqi Wang Bifeng SONG ang ChEN Qiang FU Jin CUI School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China Yangtze River Delta Research Institute of Northwestern Polytechnical University Taicang 215400China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518057China School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China

This paper establishes and analyzes a high-fidelity nonlinear time-periodic dynamic model and the corresponding state observer for flapping vibration suppression of a novel tailless Flapping Wing Micro Air Vehicle(FWMAV),named ***,a complete modeling of NPU-Tinybird is determined,including the aerodynamic model based on the quasi-steady method,the kinematic and dynamic model about the mechanism of flapping and attitude control,combined with the single rigid body dynamic *** on this,a linearized longitudinal pitch dynamic cycle-averaged model is obtained and analyzed through the methods of neural network fitting and system identification,preparing for the design of flapping vibration suppression *** vibration is an inherent property of the tailless FWMAV,which arises from the influence of time-periodic aerodynamic forces and *** can be captured by attitude and position sensors on the plane,which impairs the flight performance and efficiency of flight controller and *** deal with this problem,a novel state observer for flapping vibration suppression is designed.A robust optimal controller based on the linear quadratic theory is also designed to stabilize the closed-loop *** results are given to verify the performance of the observer,including the closed loop responses combined with robust optimal controller,the comparison of different parameters of observer and the comparison with several classic methods,such as Kalman filter,h-infinity filter and low-pass filter,which prove that the novel observer owns a fairly good suppression effect on flapping vibration and benefits for the improvement of flight performance and control efficiency.

关键词： Flapping vibration Flapping wing linear quadratic theory Robust control State observer

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Real-time mosaicking for infrared videos from an oblique sweeping camera

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Chinese Journal of Aeronautics 2021年第1期34卷 309-319页

作者： Jiazhen lU Fangde SUN Jing DONG Songlai hAN ang SU School of Aeronautics and Astronautics Central South UniversityChangsha 410083China Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China

Image mosaicking is widely used in Geographic Information Systems(GISs)for largescale ground surface ***,most existing mosaicking methods can only be used in offline processing due to the enormous amounts of *** this paper,we propose a novel and practical algorithm for real-time infrared video *** achieve this,a novel fast template matching algorithm based on Sum of Cosine Differences(SCD)is proposed to coarsely match the sequential *** high speed of the proposed template matching algorithm is obtained by computing correlation with Fast Fourier Transform(FFT).We also propose a novel fast least Squares Matching(lSM)algorithm for inter-frame fine registration,which can significantly reduce the computation without degrading the matching *** addition,the proposed fast lSM can effectively adapt for noise degradation and geometric *** on the proposed fast template matching algorithm and fine registration algorithm,we develop a practical real-time mosaicking approach which can produce seamless mosaic image highly *** on synthetic and real-world datasets demonstrate that the proposed algorithm is not just computationally efficient but also robust against various noise distortions.

关键词： Fast Fourier transform least squares matching Map fusion Mosaic Real-time Template matching

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Spatial Expression of Assembly Geometric Errors for Multi-axis Machine Tool Based on Kinematic Jacobian-Torsor Model

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Chinese Journal of Mechanical Engineering 2023年第2期36卷 234-248页

作者： ang Tian Shun liu Kun Chen Wei Mo Sun Jin State Key laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Shanghai Key laboratory of Digital Manufacture for Thin‑walled Structures School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Assembly geometric error as a part of the machine tool system errors has a significant influence on the machining accuracy of the multi-axis machine *** it cannot be eliminated due to the error propagation of components in the assembly process,which is generally non-uniformly distributed in the whole working space.A comprehensive expression model for assembly geometric error is greatly helpful for machining quality control of machine tools to meet the demand for machining accuracy in ***,the expression ranges based on the standard quasistatic expression model for assembly geometric errors are far less than those needed in the whole working space of the multi-axis machine *** address this issue,a modeling methodology based on the Jacobian-Torsor model is proposed to describe the spatially distributed geometric ***,an improved kinematic Jacobian-Torsor model is developed to describe the relative movements such as translation and rotation motion between assembly bodies,***,based on the proposed kinematic Jacobian-Torsor model,a spatial expression of geometric errors for the multi-axis machine tool is *** simulation and experimental verification are taken with the investigation of the spatial distribution of geometric errors on five four-axis machine *** results validate the effectiveness of the proposed kinematic Jacobian-Torsor model in dealing with the spatial expression of assembly geometric errors.

关键词： Geometric error Machine tool Jacobian-Torsor model Tolerance Spatial expression

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Recent Advances in In-Memory Computing:Exploring Memristor and Memtransistor Arrays with 2D Materials

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Nano-Micro letters 2024年第7期16卷 1-30页

作者： hangbo Zhou Sifan li Kah-Wee ang Yong-Wei Zhang Institute of high Performance Computing(IhPC) Agency for ScienceTechnology and Research(A*STAR)1 Fusionopolis Way#16-16 ConnexisSingapore 138632Republic of Singapore Department of Electrical and Computer Engineering National University of Singapore4 Engineering Drive 3Singapore 117583Republic of Singapore Institute of Materials Research and Engineering Agency for ScienceTechnology and Research(A*STAR)2 Fusionopolis WaySingapore 138634Republic of Singapore

The conventional computing architecture faces substantial chal-lenges,including high latency and energy consumption between memory and processing *** response,in-memory computing has emerged as a promising alternative architecture,enabling computing operations within memory arrays to overcome these *** devices have gained significant attention as key components for in-memory computing due to their high-density arrays,rapid response times,and ability to emulate biological *** these devices,two-dimensional(2D)material-based memristor and memtransistor arrays have emerged as particularly promising candidates for next-generation in-memory computing,thanks to their exceptional performance driven by the unique properties of 2D materials,such as layered structures,mechanical flexibility,and the capability to form *** review delves into the state-of-the-art research on 2D material-based memristive arrays,encompassing critical aspects such as material selection,device perfor-mance metrics,array structures,and potential ***,it provides a comprehensive overview of the current challenges and limitations associated with these arrays,along with potential *** primary objective of this review is to serve as a significant milestone in realizing next-generation in-memory computing utilizing 2D materials and bridge the gap from single-device characterization to array-level and system-level implementations of neuromorphic computing,leveraging the potential of 2D material-based memristive devices.

关键词： 2D materials Memristors Memtransistors Crossbar array In-memory computing

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Transparent,Ultra-Stretching,Tough,Adhesive Carboxyethyl Chitin/Polyacrylamide hydrogel Toward high-Performance Soft Electronics

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Nano-Micro letters 2023年第1期15卷 161-182页

作者： Jipeng Zhang Yang hu lina Zhang Jinping Zhou ang lu College of Chemistry and Molecular Sciences Wuhan UniversityWuhan 430072People’s Republic of China hubei Engineering Center of Natural Polymer-Based Medical Materials Wuhan UniversityWuhan 430072People’s Republic of China

To date,hydrogels have gained increasing attentions as a flexible conductive material in fabricating soft ***,it remains a big challenge to integrate multiple functions into one gel that can be used widely under various ***,a kind of multifunc-tional hydrogel with a combination of desirable characteristics,including remarkable transparency,high conductivity,ultra-stretchability,tough-ness,good fatigue resistance,and strong adhesive ability is presented,which was facilely fabricated through multiple noncovalent crosslinking *** resultant versatile sensors are able to detect both weak and large deformations,which owns a low detection limit of 0.1%strain,high stretchability up to 1586%,ultrahigh sensitivity with a gauge factor up to 18.54,as well as wide pressure sensing range(0-600 kPa).Meanwhile,the fabrication of conductive hydrogel-based sensors is demonstrated for various soft electronic devices,including a flexible human-machine interactive system,the soft tactile switch,an integrated electronic skin for unprecedented nonplanar visualized pressure sensing,and the stretchable triboelectric nanogenerators with excellent biomechanical energy harvesting *** work opens up a simple route for multifunctional hydrogel and promises the practical application of soft and self-powered wearable electronics in various complex scenes.

关键词： Conductive hydrogels Multifunctional sensors human-machine interaction Electronic skin Stretchable triboelectric nanogenerators

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From blood to brain:amoeboid microglial cell,a nascent macrophage and its functions in developing brain

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Acta Pharmacologica Sinica 2007年第8期28卷 1087-1096页

作者： Charanjit KAUR S Thameem DhEEN Eng-ang lING Department of Anatomy Yong loo lin School of Medicine National University of Singapore117597Singapore

Amoeboid microglial cells(AMC)in the developing brain are active *** macrophagic nature of these cells has been demonstrated by many methods,such as the localization of various hydrolytic enzymes and the presence of comple-ment type 3 surface receptors in *** importantly is the direct visualizationof these cells engaged in the phagocytosis of degenerating cells at the ultrastruc-tural *** evidence of them being active macrophages is the avid inter-nalization of tracers administered by the intravenous or intraperitoneal routes indeveloping *** potential involvement of AMC in immune functions is sup-ported by the induced expression of major histocompatibility complex class I andII antigens on them when challenged by lipopolysaccharide or interferon-γ.Im-munosuppressive drugs,such as glucocorticoids and immune function-enhanc-ing drugs like melatonin,affect the expression of surface receptors and antigensand the release of cytokines by *** studies in our laboratory haveshown the expression of insulin-like growth factors,endothelins,2',3'-cyclic nucle-otide 3'-phosphodiesterase,and N-methyl-D-asparate *** along withthe release of chemokines,such as stromal derived factor-la and monocytechemoattractant protein-1,suggests multiple functional roles of AMC in earlybrain development.

关键词： developing brain amoeboid microglial cells functions

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Targeting key signalling pathways in oesophageal adenocarcinoma:A reality for personalised medicine?

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World Journal of Gastroenterology 2011年第23期17卷 2781-2790页

作者： Richard R Keld Yeng S ang Department of Gastroenterology Royal Albert Edward InfirmaryWigan LaneWiganGreater ManchesterWN1 2NNUnited Kingdom School of Translational Medicine Faculty of Medical and Human SciencesThe University of ManchesterManchesterM13 9PLUnited Kingdom

Cancer treatments are rapidly *** treatment for oesophageal adenocarcinoma currently involves surgery and cytotoxic chemotherapy or *** for both regimes are generally poor as a result of tumor *** have reviewed the key signalling pathways associated with oesophageal adenocarcinomas and discussed the recent trials of novel agents that attempt to target these *** are many trials underway with the aim of improving survival in oesophageal ***,phase 2 and 3 trials are focused on MAP kinase inhibition,either through inhibition of growth factor receptors or signal transducer *** order to avoid tumor resistance,it appears to be clear that targeted therapy will be needed to combat the multiple signalling pathways that are in operation in oesophageal *** may be achievable in the future with the advent of gene signatures and a combinatorial approach.

关键词： Oesophageal adenocarcinoma Signallingpathways MAP and PI3 Kinase pathways Wnt signalling Transforming growth factor-13 pathway Nuclear factor-KBpathways Transcription factors Tyrosine kinase receptors

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Prognostic effect analysis of molecular subtype on young breast cancer patients

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Chinese Journal of Cancer Research 2015年第4期27卷 428-436页

作者： hong-liang Chen ang Ding Fu-Wen Wang Department of Breast Surgery Obstetrics and Gynecology Hospital of Fudan University

Objective： To make a prognostic effect analysis of molecular subtype on young breast cancer ***： Totally 187 cases of young breast cancer patients less than 40 years old treated in Obstetrics and Gynecology hospital of Fudan University between June 2005 and June 2011 were included in our study. We described their clinical-pathological characteristics, disease-free survival（DFS） rate, and overall survival（OS） rate after a median follow-up period of 61 months. The factors associated with prognosis were also evaluated by univariate and multivariate ***： All patients were premenopausal, with an average age of 35.36±3.88 years old. The mean tumor size was 2.43±1.53 cm. Eighty-one cases had lymph node metastasis（43.3%）, 126 cases had lymphovascular invasion（67.4%）, and 125 cases had histological grade III（66.8%） disease. Twenty-seven cases（14.4%） were luminal A subtype, 99 cases（52.9%） were luminal B subtype, 29 cases（15.5%） were human epidermal growth factor receptor 2（hER-2） overexpression subtype, while 32 cases（17.1%） were triple negative breast cancer（TNBC） subtype according to 2013 St Gallen expert consensus. One hundred and thirty-five cases underwent mastectomy whereas 52 cases had breast-conserving surgery. One hundred and seventy-eight cases underwent adjuvant or neoadjuvant chemotherapy. Recurrence or metastasis occurred in 29 cases, 13 of which died. The 5-year DFS and OS rates were 84% and 92%. Multivariate analysis showed that nodal status（P=0.041） and molecular subtype（P=0.037） were both independent prognostic factors of DFS, while nodal status（P=0.037） and TNBC subtype（P=0.048） were both independent prognostic factors of OS. Conclusions： Molecular subtype is an independent prognostic factor of young breast cancer patients. TNBC has a high risk of relapse and death.

关键词： Molecular subtype young breast cancer prognosis

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GAAF:Searching Activation Functions for Binary Neural Networks Through Genetic Algorithm

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Tsinghua Science and Technology 2023年第1期28卷 207-220页

作者： Yanfei li Tong Geng Samuel Stein ang li huimin Yu Department of Information Science and Electronic Engineering Zhejiang UniversityHangzhou 310027China h Pacific Northwest National laboratory RichlandWA 99354USA

Binary neural networks(BNNs)show promising utilization in cost and power-restricted domains such as edge devices and mobile *** is due to its significantly less computation and storage demand,but at the cost of degraded *** close the accuracy gap,in this paper we propose to add a complementary activation function(AF)ahead of the sign based binarization,and rely on the genetic algorithm(GA)to automatically search for the ideal *** AFs can help extract extra information from the input data in the forward pass,while allowing improved gradient approximation in the backward *** novel AFs are identified through our GA-based search,while most of them show improved performance(up to 2.54%on ImageNet)when testing on different datasets and network ***,periodic functions are identified as a key component for most of the discovered AFs,which rarely exist in human designed *** method offers a novel approach for designing general and application-specific BNN *** will be released on Github.

关键词： binary neural networks(BNNs) genetic algorithm activation function

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