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Selection of regression models for predicting strength and deformability properties of rocks using GA

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International Journal of Mining Science and technology 2013年第4期23卷 492-498页

作者： Manouchehrian Amin Sharifzadeh Mostafa Hamidzadeh Moghadam Rasoul Nouri Tohid Mining engineering Department Sahand University of Technology Department of Mining and Metallurgical engineering Amirkabir University of Technology Department of Mining engineering Western Australian School of minesCurtin University

Recently,many regression models have been presented for prediction of mechanical parameters of rocks regarding to rock index *** statistical analysis is a common method for developing regression models,but still selection of suitable transformation of the independent variables in a regression model is *** this paper,a genetic algorithm(GA)has been employed as a heuristic search method for selection of best transformation of the independent variables(some index properties of rocks)in regression models for prediction of uniaxial compressive strength(UCS)and modulus of elasticity(E).Firstly,multiple linear regression(MLR)analysis was performed on a data set to establish predictive ***,two GA models were developed in which root mean squared error(RMSE)was defned as ftness *** have shown that GA models are more precise than MLR models and are able to explain the relation between the intrinsic strength/elasticity properties and index properties of rocks by simple formulation and accepted accuracy.

关键词： Regression models Genetic algorithms Heuristics Uniaxial compressive strength Modulus of elasticity Rock index property

Correlation between precipitates evolution and mechanical properties of Al-Sc-Zr alloy with Er additions

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Journal of Materials Science & technology 2022年第4期99卷 61-72页

作者： Li Liu Jian-Tang Jiang Xiang-Yuan Cui Bo Zhang Liang Zhen Simon P.Ringer School of Materials Science and engineering Harbin Institute of TechnologyHarbin 150001China China-Ukraine Institute of Welding Guangdong Academy of SciencesGuangzhou 510651China School of Aerospace Mechanical and Mechatronic Engineeringand Australian Centre for Microscopy and MicroanalysisThe University of SydneyNew South Wales 2006Australia School of Materials Science and engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China

Correlation between precipitates evolution and mechanical properties of Al-Sc-Zr alloy with Er additions during isothermal ageing were investigated by microhardness measurements,transmission electron microscopy,atom probe tomography and density functional theory-based *** results demonstrate that the Er additions significantly improve the hardness during elevated temperature ageing,especially at 400℃.This is mainly because Er additions increase the nucleation rate of the Al_(3)(Er,Sc,Zr)precipitates,resulting in a higher density of fine and uniform dispersion of L1_(2)structured ***-principles calculations demonstrate that the second nearest neighboring solute-solute interactions for the species Sc,Zr and Er are energetically favored–a key feature to rationalize the observed precipitate structure and the underlying formation *** sequential formation of the core/shell precipitates in the Er-free alloy and core/double-shell precipitates in the Er-containing alloy arises due to the different solute-solute and solute-vacancy interaction energies,and the relative diffusivities of the Er,Sc and Zr species in *** results shed light on the beneficial effects of Er additions on the agehardening behavior of Al-Sc-Zr alloy and provide guidance for designing the ageing treatments for the Al-Sc-Zr(-Er)alloys.

关键词： Al alloys Isothermal ageing Microhardness Transmission electron microscopy Atom probe tomography First-principles calculations

Nitrogen cold plasma treatment stabilizes Cu^(0)/Cu^(+) electrocatalysts to enhance CO_(2) to C2 conversion

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Journal of Energy Chemistry 2023年第9期84卷 321-328页

作者： Qiang Zhang Jianlin Wang Fang Guo Ge He Xiaohui Yang Wei Li Junqiang Xu Zongyou Yin School of Chemistry&Chemical engineering Chongqing University of TechnologyChongqing 400054China College of Biomass Science and engineering Sichuan UniversityChengdu 610065SichuanChina Chongqing Institute of Green and Intelligent technology Chinese Academy of SciencesChongqing 400714China Research School of Chemistry Australian National UniversityCanberraACT 2601Australia

Cu-based materials are ideal catalysts for CO_(2) electrocatalytic reduction reaction(CO_(2)RR) into multicarbon ***,such reactions require stringent conditions on local environments of catalyst surfaces,which currently are the global pressing ***,a stabilized activation of Cu^(0)/Cu^(+)-onAg interface by N_(2) cold plasma treatment was developed for improving Faradaic efficiency(FE) of CO_(2)RR into C2 *** resultant Ag@Cu-CuN_x exhibits a C2 FE of 72% with a partial current density of-14.9 mA cm^(-2) at-1.0 V ***(reversible hydrogen electrode).Combining density functional theory(DFT) and experimental investigations,we unveiled that Cu^(0)/Cu^(+) species can be co ntrollably tu ned by the incorporation of nitrogen to form CuN_x on Ag surface,i.e.,Ag@Cu-CuN_*** strategy enhances ^(*)CO intermediates generation and accelerates C-C coupling both thermodynamically and *** intermediates O^(*)C^(*)CO,^(*)COOH,and ^(*)CO were detected by in-situ attenuated total internal reflection surface enhanced infrared absorption spectroscopy(ATR-SEIRAS).The uncovered CO_(2)RR-into-C2 products were carried out along CO_(2)→^(*)COOH→^(*)CO→O^(*)C^(*)CO→^(*)C_(2)H_(3)O→^(*)C_(2)H_(4)O→ C_(2)H_(5)OH(or ^(*)C_(2)H_(3)O→^(*)O+C_(2)H_(4)) paths over Ag@Cu-CuN_x *** work provides a new approach to design Cu-based electrocatalysts with high-efficiency,mild condition,and stable CO_(2)RR to C2 products.

关键词： Nitrogen cold plasma Cu-based metal nitride Carbon dioxide electroreduction C2 products Stabilizes

Failure-tolerant control for small agile satellites using single-gimbal control moment gyros and magnetic torquers

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Acta Mechanica Sinica 2012年第2期28卷 551-558页

作者： Tao Meng Saburo Matunaga School of aeronautics and astronautics Zhejiang University310027 HangzhouChina Dept.of Mechanical and Aerospace engineering Tokyo Institute of TechnologyJapan.Fellow-AIAA.

This paper focuses on the attitude control prob- lem of small agile satellites using single-gimbal control mo- ment gyros （CMG） and magnetic torquers （MTQ）. CMGs are regarded as effective torque generators for agile satel- lites because of their torque amplification capability. How- ever, they are vulnerable to failure due to their complex inner mechanism. In this paper, different failure cases of CMGs are analyzed. A flexible failure-tolerant control strategy is developed by automatically redistributing the required con- trol torque among the operating CMGs and MTQs, with a variable limiter to accommodate the actuator dynamics changes introduced by CMG failures. The performances of maneuvers about different directions under different failure cases are also discussed and examined. Numerical simula- tions demonstrate that the proposed strategy maintains cer- tain agility in the cases of one or two CMGs failing. More- over, a survival strategy with only one CMG left is also ver- ified. Both sun-pointing stabilization and earth-pointing sta- bilization can be achieved in this case, which fulfill some basic mission requirements.

关键词： Attitude control Failure-tolerant. Mixed steer- ing logic CMG. MTQ

Fabrication and Characterization of Well-Aligned Zn1-xMnxO Nanorods

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Chinese Physics Letters 2006年第3期23卷 716-719页

作者：常永勤张洪洲龙毅叶荣昌 School of Materials Science and engineering University of Science and Technology Beijing Beijing 100083 Department of Electronics and Material engineering Research School of Physical Science and Engineering Australian National University Australia

Well-Migned Zn1-xMnxO nanorods have been synthesized successfully on bare silicon substrates by a simple evaporation method without using any catalyst. X-ray diffraction and electron microscopy studies demonstrate that the as-grown nanorods are of single wurtzite phase with a preferential growth direction along their c- axes, Quantitative energy-dispersive spectrum analysis reveals that the concentration of manganese is around 4 at,%, Magnetic measurements show the single-phase Zn1-xMnxO nanorod arrays exhibiting the paramagnetic behaviour. Photolumlnescence spectra demonstrate that the Zn1-xMnxO nanorods preserve ultraviolet emission at room temperature.

关键词： DILUTED MAGNETIC SEMICONDUCTORS DOPED ZNO FILMS THIN-FILMS ROOM-TEMPERATURE QUANTUM WIRES ZINC OXIDE FERROMAGNETISM SPECTRA AMBIENT GROWTH

New SAR Imaging Algorithm via the Optimal Time-Frequency Transform Domain

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Computers, Materials & Continua 2020年第12期65卷 2351-2363页

作者： Zhenli Wang Qun Wang Jiayin Liu Zheng Liang Jingsong Xu Department of Computer Information and Network Security Jiangsu Police InstituteNanjingChina Research fellow Faculty of engineering and Information technology University of Technology SydneyNew South WalesAustralia

To address the low-resolution imaging problem in relation to traditional Range Doppler(RD)algorithm,this paper intends to propose a new algorithm based on Fractional Fourier Transform(FrFT),which proves highly advantageous in the acquisition of high-resolution Synthetic Aperture Radar(SAR)*** expression of the optimal order of SAR range signals using FrFT is deduced in detail,and the corresponding expression of the azimuth signal is also *** analysis shows that,the optimal order in range(azimuth)direction,which turns out to be very unique,depends on the known imaging parameters of SAR,therefore the engineering practicability of FrFT-RD algorithm can be greatly improved without the need of order *** FrFT-RD algorithm is established after an analysis of the optimal time-frequency *** results demonstrate that,compared with traditional RD algorithm,the main-lobe width of the peak-point target of FrFT-RD algorithm is narrow in both range and azimuth *** the peak amplitude of the first side-lobe is reduced significantly,those of other side-lobes also drop in various *** this way,the imaging resolution of range and azimuth can be increased considerably.

关键词： Fourier transform fractional Fourier transform synthetic aperture radar range doppler algorithm

Bolt-grouting combined support technology in deep soft rock roadway

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International Journal of Mining Science and technology 2016年第5期26卷 777-785页

作者： Chen Yanlong Meng Qingbin Xu Guang Wu Haoshuai Zhang Guimin State Key Laboratory for Geomechanics and Deep Underground engineering China University of Mining & Technology Department of Mining engineering & Metallurgical engineering Western Australian School of Mines Curtin University School of Mechanics and Civil engineering China University of Mining & Technology

Analyzing the mineral composition, mechanical properties and ground stress testing in surrounding rock,the study investigated the failure mechanism of deep soft rock roadway with high stress. The boltgrouting combined support system was proposed to prevent such failures. By means of FLAC3D numerical simulation and similar material simulation, the feasibility of the support design and the effectiveness of support parameters were discussed. According to the monitoring the surface and deep displacement in surrounding rock as well as bolt axial load, this paper analyzed the deformation of surrounding rock and the stress condition of the support structure. The monitor results were used to optimize the proposed support scheme. The results of field monitors demonstrate that the bolt-grouting combined support technology could improve the surround rock strength and bearing capacity of support structure, which controlled the great deformation failure and rheological property effectively in deep soft rock roadway with high stress. As a result, the long term stability and safety are guaranteed.

关键词： Deep soft rock roadway Bolt-grouting support Numerical simulation Similar material simulation High stress

Reducing the vacancies associated with ferroelectric polarization to promote photocatalytic overall water splitting

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Science China Chemistry 2024年第10期67卷 3258-3264页

作者： Haozhi Qi Yuyang Kang Jian-An Liu Lichang Yin Wenyu Zhang Shangyi Ma Jianhang Qiu Lingli Li Weijin Hu Lianzhou Wang Gang Liu Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and engineering University of Science and Technology of ChinaShenyang 110016China Nanomaterials Centre School of Chemical Engineering and Australian Institute for Bioengineering and NanotechnologyThe University of QueenslandSt LuciaBrisbane QLD 4072Australia

Ferroelectric materials hold great promise in photocatalytic water splitting because their built-in electric field induced by the depolarization field can fulfill the separation of photogenerated ***,a number of intrinsic charged vacancy defects are simultaneously generated to screen the depolarized field for stabilizing the crystal structure,always resulting in severe recombination of photogenerated carriers and thus poor overall water splitting ***,we proposed a strategy to promote the separation and transport of photogenerated carriers of ferroelectric photocatalysts by adjusting the ferroelectric polarization and altering the coordination environment of elements to reduce the defect ***,we prepared a series of Ta-doped PbTiO_(3)with low Pb(V_(Pb))and O(V_(O))vacancy concentrations by reducing the polarization intensity and strengthening the Pb–O *** Ta-doped PbTiO_(3)shows efficient charge separation and greatly enhanced photocatalytic overall water splitting activity with the assistance of *** work highlights the importance of regulating ferroelectric polarization and vacancy defect concentration by the doping strategy in charge separation for photocatalytic water splitting.

关键词： PbTiO_(3) ferroelectric polarization vacancy defect element doping photocatalytic overall water splitting

VBMq： pursuit baremetal performance by embracing block I/O parallelism in virtualization

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Frontiers of Computer Science 2018年第5期12卷 873-886页

作者： Diming ZHANG Fei XUE Hao HUANG Shaodi YOU Faculty of Computer Science and technology Nanjing University Nanjing 210023 China College of Computer Science and engineering Jiangsu University of Science and Technology Zhenjiang 212003 China College of engineering and Computer Science Australian National University Canberra 2600 Australia Data61-CSIRO Australian National University Canberra 2600 Australia

Barely acceptable block I/O performance prevents virtualization from being widely used in the HighPerformance Computing field. Although the virtio paravirtual framework brings great I/O performance improvement, there is a sharp performance degradation when accessing high-performance NAND-flash-based devices in the virtual machine due to their data parallel design. The primary cause of this fact is the deficiency of block I/O parallelism in hypervisor, such as KVM and Xen. In this paper, we propose a novel design of block I/O layer for virtualization, named VBMq. VBMq is based on virtio paravirtual I/O model, aiming to solve the block I/O parallelism issue in virtualization. It uses multiple dedicated I/O threads to handle I/O requests in parallel. In the meanwhile, we use polling mechanism to alleviate overheads caused by the frequent context switches of the VM＇s notification to and from its hypervisor. Each dedicated I/O thread is assigned to a non-ovedapping core to improve performance by avoiding unnecessary scheduling. In addition, we configure CPU affinity to optimize I/O completion for each request. The CPU affinity setting is very helpful to reduce CPU cache miss rate and increase CPU efficiency. The prototype system is based on Linux 4.1 kernel and QEMU 2.3.1. Our measurements show that the proposed method scales graciously in the multi-core environment, and provides performance which is 39.6x better than the baseline at most, and approaches bare-metal performance.

关键词： high-performance parallelism paravirtual I/O