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Experimental study of dynamic mechanical properties of reactive powder concrete under high-strain-rate impacts

Science China(technological Sciences) 2010年第9期53卷 2435-2449页

作者： JU Yang1,2.LIU HongBin1,SHEnG GuoHua1,3 & WAnG HuiJie1 1 State Key Laboratory of Coal Resources and Safe Mining,Beijing Key Laboratory of Fracture and Damage Mechanics of Rocks and Concrete,China university of Mining and technology,Beijing 100083,China 2.department of Mechanical and {2. engineering,university of calgary,2.00 university drive,ab t2. 1n4,canada 3 School of Resources and Civil engineering,northeastern university,Shenyang 110004,China 1. State Key Laboratory of Coal Resources and Safe Mining Beijing Key Laboratory of Fracture and Damage Mechanics of Rocks and Concrete China University of Mining and Technology Beijing 100083 China2. Department of Mechanical and Manufacturing Engineering University of Calgary 2500 University Drive AB T2N 1N4 Calgary Canada3. School of Resources and Civil Engineering Northeastern University Shenyang 110004 China

the dynamic mechanical properties of reactive powder concrete subjected to compressive impacts with high strain rates ranging from 10 to 1.1×102.s-1 were investigated by means of SHPB (split-Hopkinson-pressure-bar) tests of the cylindrical specimens with five different steel fiber volumetric *** properties of wave stress transmission,failure,strength,and energy consumption of RPC with varied fiber volumes and impact strain rates were *** influences of impact strain rates and fiber volumes on those properties were characterized as *** general forms of the dynamic stress-strain relationships of RPC were modeled based on the experimental *** investigations indicate that for the plain RPC the stress response is greater than the strain response,showing strong brittle *** RPC with a certain volume of fibers sustains higher strain rate impact and exhibits better deformability as compared with the plain *** a constant fiber fraction,the peak compressive strength,corresponding peak strain and the residual strain of the fiber-reinforced RPC rise by varying amounts when the impact strain rate increases,with the residual strain demonstrating the greatest *** the fiber content makes trivial contribution to improving the residual deformability of RPC when the impact strain rate is *** tests also show that the fiber content affects the peak compressive strength and the peak deformability of RPC in a different *** a constant impact strain rate and the fiber fraction less than 1.75%,the peak compressive strength rises with an increasing fiber *** peak compressive strength tends to decrease as the fiber volume exceeds 1.75%.the corresponding peak strain,however,incessantly rises with the increasing fiber *** total energy Edisp that RPC consumed during the period from the beginning of impacts to the time of residual strains elevates with the fiber volume increment as long as the fiber fraction

关键词： impact reactive powder concrete (RPC) high strain rate dynamic strength energy consumption dynamic stress-strain response

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Rolling Element Bearing Diagnostics by Combination of Envelope Analysis and Wavelet transform

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Journal of university of Science and technology Beijing 2001年第1期8卷 69-74页

作者： Ying tang, Qiao Sun Mechanical engineering School, university of Science and technology Beijing, Beijing 100083, China {2. of Mechanical engineering, university of calgary calgary Alberta t2. 1n4, canada Univ Sci & technol Beijing Sch Mech Engn Beijing 100083 Peoples R China Univ calgary Dept Mech Engn Calgary AB T2N 1N4 Canada

Rolling element-bearing diagnostics has been studied over the last thirty years, and envelope analysis is widely recognized as being the best approach for detection and diagnosis of rolling element bearing incipient failure. But one of the on-going difficulties with envelope technique is to determine the best frequency band to envelop. Here, wavelet transform technique is introduced into envelope analysis to solve the problem by capturing bearing defects-sensory scales (i.e. frequency bands). A modulated Gaussian function is chosen to be the analytical wavelet because it coincides well with bearing defect-induced vibration signal patterns. Vibration signals measured from railway bearing tests were studied by the proposed method. Cases of bearings with single and multiple defects on inner and outer race under different testing conditions are presented. Experimental results showed that the proposed method allowed a more accurate local description and separation of transient signal part, which were caused by impacts between defects and the mating surfaces in the bearing. the combination method provides an effective signal detection technique for rolling element-bearing diagnostics.

关键词： continuous wavelet transform envelope analysis rolling element bearing diagnostics

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numerical simulation of mechanisms of deformation,failure and energy dissipation in porous rock media subjected to wave stresses

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Science China(technological Sciences) 2010年第4期53卷 1098-1113页

作者： JU Yang1,2.WAnG HuiJie1,YAnG YongMing1,HU QinAng3 & PEnG RuiDong1 1 State Key Laboratory of Coal Resources and Safe Mining,Beijing Key Laboratory of Fracture and Damage Mechanics of Rock and Concrete,China university of Mining and technology,Beijing 100083,China 2.department of Mechanical and {2. engineering,university of calgary,calgary,Alberta,t2. 1n4,canada 3 School of Environment and Civil engineering,College of engineering,Oklahoma State university,Stillwater,OK 74078,USA 1. State Key Laboratory of Coal Resources and Safe Mining Beijing Key Laboratory of Fracture and Damage Mechanics of Rock and Concrete China University of Mining and Technology Beijing 100083 China2. Department of Mechanical and Manufacturing Engineering University of Calgary Calgary Alberta T2N 1N4 Canada3. School of Environment and Civil Engineering College of Engineering Oklahoma State University Stillwater OK 74078 USA

the pore characteristics,mineral compositions,physical and mechanical properties of the subarkose sandstones were acquired by means of Ct scan,X-ray diffraction and physical tests.A few physical models possessing the same pore characteristics and matrix properties but different porosities compared to the natural sandstones were *** 3D finite element models of the rock media with varied porosities were established based on the Ct image processing of the physical models and the MIMICS software *** failure processes of the porous rock media loaded by the split Hopkinson pressure bar(SHPB) were simulated by satisfying the elastic wave propagation *** dynamic responses,stress transition,deformation and failure mechanisms of the porous rock media subjected to the wave stresses were *** is shown that an explicit and quantitative analysis of the stress,strain and deformation and failure mechanisms of porous rocks under the wave stresses can be achieved by using the developed 3D finite element *** applied wave stresses of certain amplitude and velocity,no evident pore deformation was observed for the rock media with a porosity less than 15%.the deformation is dominantly the combination of microplasticity(shear strain),cracking(tensile strain) of matrix and coalescence of the cracked regions around *** stresses lead to microplasticity,while tensile stresses result in cracking of the *** and coalescence of the matrix elements in the neighborhood of pores resulted from the high transverse tensile stress or tensile strain which exceeded the threshold *** simulation results of stress wave propagation,deformation and failure mechanisms and energy dissipation in porous rock media were in good agreement with the physical *** present study provides a reference for analyzing the intrinsic mechanisms of the complex dynamic response,stress transit mode,deformation and failure mechanisms and the disaster mechanism

关键词： porous media three-dimensional finite element model rock media stress wave failure mechanism energy dissipation

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nAnOStRUCtURES OF FUnCtIOnAL BLOCK COPOLYMERS

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Chinese Journal of Polymer Science 2000年第3期18卷 255-262页

作者： Guojun Liu department of Chemistry, university of calgary, {2. university Dr., nW, calgary, Alberta, canada t2. In4 Univ calgary Dept Chem Calgary AB T2N 1N4 Canada

nanostructure fabrication from block copolymers in my group normally involves polymer design, synthesis, self-assembly, selective domain crosslinking, and sometimes selective domain removal. Preparation of thin films withnanochannels was used to illustrate the strategy we took. In this particular case, a linear triblock copolymer polyisoprenc-block-poly(2.cinnamoylethyl methacrylate)-block-poly(t-butyl acrylate), PI-b-PCEMA-b-PtBA, was used. Films, 2. to50 μm thick, were prepared from casting on glass slides a toluene solution of PI-b-PCEMA-b-PtBA and PtBA homopolymer,hPtBA, where hPtBA is shorter than the PtBA block. At the hPtBA mass faction of 2.% relative to the triblock or the totalPtBA (hPtBA and PtBA block) volume fraction of 0.44, hPtBA and PtBA formed a seemingly continuous phase in the matrixof PCEMA and Pl. Such a block segregation pattern was locked in by photocrosslinking the PCEMA domain. nanochannelswere formed by extracting out hPtBA with solvent. Alternatively. larger channels were obtained from extracting out hPtBAand hydrolyzing the t-butyl groups of the PtBA block. Such membranes were not liquid permeable but had gas permeabilityconstants ～6 orders of magnitude higher than that of low-density polyethylene films.

关键词： nanostructures Block copolymers nanochannel generation Self-Assembly Polyisoprene-b-poly(2.cinnanoylethyl methacrylate)-b-poly(t-butyl acrylate)

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the relaxing ori-ter balance of Mycoplasma genomes

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Science China(Life Sciences) 2008年第2期51卷 182-189页

作者： ZHEnG Xin1 & LIU ShuLin1,2.1 department of Microbiology, Peking university Health Science Center, Beijing 100083, China {2. of Microbiology and Infectious Diseases, university of calgary, calgary, t2. 4n1, canada 1. department of Microbiology Peking University Health Science Center Beijing 100083 China 2. department of Microbiology and Infectious Diseases University of Calgary Calgary T2N 4N1 Canada

Mycoplasma are wall-less bacteria with small genomes, which are thought to have resulted from massive genome reductive processes, during which the ori-ter balance may be disrupted. For technical difficulties, ori and ter have been located only in a few Mycoplasma strains. Using the Z curve method, we were able to locate turning points on the Mycoplasma genomes, with the minimum and maximum points co-locating with ori or ter in the reference genomes. Assuming Z curve correctly located ori and ter, we calculated the distances from ori to ter in both directions on the circular genome and calculated the ori-ter balance status. the Mycoplasma genomes were not balanced, possibly as a result of close association of Mycoplasma with hosts, where there would be no other microbes for Mycoplasma to compete with for nutrients, so fastest possible growth related to balanced genomes might not be needed by Mycoplasma, leading to a relaxing ori-ter balance.

关键词： Z curve Mycoplasma genome balance ori and ter evolution

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Biodegradation and origin of oil sands in the Western canada Sedimentary Basin

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Petroleum Science 2008年第2期5卷 87-94页

作者： Zhou Shuqing Huang Haiping Liu Yuming School of Energy Resource China University of Geosciences Beijing 100083 China department of Geology and Geophysics University of Calgary T2N 1N4 Calgary Canada

the oil sands deposits in the Western canada Sedimentary Basin （WCSB） comprise of at least 85% of the total immobile bitumen in place in the world and are so concentrated as to be virtually the only such deposits that are economically recoverable for conversion to oil. the major deposits are in three geographic and geologic regions of Alberta： Athabasca, Cold Lake and Peace River. the bitumen reserves have oil gravities ranging from 8 to 12. API, and are hosted in the reservoirs of varying age, ranging from Devonian （Grosmont Formation） to Early Cretaceous （Mannville Group）. they were derived from light oils in the southern Alberta and migrated to the north and east for over 100 km during the Laramide Orogeny, which was responsible for the uplift of the Rocky Mountains. Biodegradation is the only process that transforms light oil into bitumen in such a dramatic way that overshadowed other alterations with minor contributions. the levels of biodegradation in the basin increasing from west （non-biodegraded） to east （extremely biodegraded） can be attributed to decreasing reservoir temperature, which played the primary role in controlling the biodegradation regime. Once the reservoir was heated to approximately 80℃, it was pasteurized and no biodegradation would further occur. However, reservoir temperature could not alone predict the variations of the oil composition and physical properties. Compositional gradients and a wide range ofbiodegradation degree at single reservoir column indicate that the water-leg size or the volume ratio of oil to water is one of the critical local controls for the vertical variations ofbiodegradation degree and oil physical properties. Late charging and mixing of the fresh and degraded oils ultimately dictate the final distribution of compositions and physical properties found in the heavy oil and oil sand fields. Oil geochemistry can reveal precisely the processes and levels that control these variations in a given field, which opens the

关键词： Western canada Sedimentary Basin (WCSB) oil sands biodegradation mixing

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High-accuracy topographical information extraction based on fusion of AStER stereo-data and ICESat/GLAS data in Antarctica

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Science China Earth Sciences 2009年第5期52卷 714-722页

作者： E DongChen1,3,SHEn Qiang2.XU Ying1,3 & CHEn Gang4 1 Chinese Antarctic Center of Surveying and Mapping,Wuhan university,Wuhan 430079,China 2.Institute of Seismology China Earthquake Administration,Wuhan 430071,China 3 Key Laboratory of Polar Surveying and Mapping,State Bureau of Surveying and Mapping,Wuhan university,Wuhan 430079,China 4 {2. of Geography,university of calgary,calgary,Alberta t2. 1n4,canada Chinese Antarctic Center of Surveying and Mapping Wuhan University Wuhan 430079 China Institute of Seismology China Earthquake Administration Wuhan 430071 China Key Laboratory of Polar Surveying and Mapping State Bureau of Surveying an

In order to better support Antarctic inland ice sheet expedition from Zhongshan Station to Dome A,the topographic data are *** present,although the entire Antarctic DEM provided by RAMP(Ra-darsat Antarctic Mapping Project) was estimated at the highest horizontal(spatial) resolution of about 2.0 m,the real horizontal resolution of the DEM varies from place to place depending on the density and scale of the original source *** ice shelves and the inland ice sheet,the horizontal resolution is about 5 km;the vertical accuracy is estimated to be ±50 m in interior East Antarctic ice sheet and away from the mountain ***,more accurate topographic data are unavailable in *** order to meet the requirements of high-accuracy topographic information for further researches,this paper mainly addresses a fusion study of AStER stereo pairs and ICESat/GLAS altimetry data for extraction of high-accuracy DEM in East Antarctica,based on the high horizontal resolution(15 m) of AStER and vertical accuracy(13.8 cm) of ICESat/***,some altimetry data were selected as vertical control points to reduce errors of image correlation matching during the extraction of AStER-based ***,ice sheet altimetry data derived from ICESat were used to generate DEM ranging from 75° to 81°S because existing AStER data do not cover this area and high density of the coverage of ICESat altimetry ***,the DEM in coverage of the expedition route was *** analysis of result reveals that the DEM accuracy is improved *** absolute vertical accuracy of DEM is higher than 15 m in some cases and higher than 30 m for all the areas along the expedition route except from the 009-001 scene;the interior accuracy is higher than 15 m and higher than 7 m in some *** can meet the requirements of topographic map at 1:50000 scale,which is an economic and advantageous method to produce the topographic products.

关键词： DEM Antarctica Zhongshan Station Dome A AStER ICESat GLAS

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A StREAMLInE-BASED PREDICtIVE MODEL FOR EnHAnCED-OIL-RECOVERY POtEntIALItY

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Journal of Hydrodynamics 2008年第3期20卷 314-322页

作者： HOU Jian ZHAnG Shun-kang DU Qing-jun LI Yu-bin College of Petroleum engineering China University of Petroleum （East China） Dongying 257061 China Chemical and Petroleum department University of Calgary Calgary T2N 1N4 Canada

A pseudo-three-dimensional model of potentiality prediction is proposed for enhanced oil recovery, based on the streamline method described in this article. the potential distribution of the flow through a porous medium under a complicated boundary condition is solved with the boundary element method. Furthermore, the method for tracing streamlines between injection wells and producing wells is presented. Based on the results, a numerical solution can be obtained by solving the seepage problem of the stream-tube with consideration of different methods of Enhanced Oil Recovery（EOR）. the advantage of the method given in this article is that it can obtain dynamic calculation with different well patterns of any shape by easily considering different physicochemical phenomena having less calculation time and good stability. Based on the uniform theory basis-streamline method, different models, including CO2.miscible flooding, polymer flooding, alkaline/surfactant/polymer flooding and microbial flooding, are established in this article.

关键词： boundary element method streamline method Enhanced Oil Recovery(EOR) CO2.miscible flooding chemical flooding microbial flooding

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MICROMACHInInG WItH FEMtOSECOnD LASER

MICROMACHINING WITH FEMTOSECOND LASER

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第七届海内外青年设计与制造科学会议

作者： Yiliu tu and Ming Xia department of Mechanical and manufacturing {2. university of calgary calgary ab canada t2. 1n4

＜正＞Femtosecond laser micromachining is a new approach emerging in MEMS area in recent years. Although some applications have been reported, this technology is still not matured and not understood very well. Femtosecond lasers currently show much promise as potential effective tools in micromachining or micro-system applications, which include industrial material processing, biomedicine, photonics, and semiconductors. this paper reviewed femtosecond laser technology with emphasis on mode-locked technology and chirped pulsed amplification （CPA）. We described the most important difference between femtosecond laser and traditional lasers, which is multiphoton absorption during laser material interaction. We introduced the configuration and principle of our femtosecond laser micromachining workstation and the status of micromachining with femtosecond laser pulses in the literature. Some advantages and applications such as processing different materials including transparent materials and creating very fine features （on the order of tens of nm） are presented. Finally, we suggested several future efforts that are parameter selection and optimization of micromachining processing, development of process and tolerance control algorithms, development of sensors and measurement methods, and development of the theory and methods of design for the femtosecond laser micromachining application. to achieve these targets effectively we proposed a "free force" 3D micromachining concept using lasers including femtosecond laser to create micro and nanostructures.

关键词： Laser Micromachining Femtosecond Laser Ultrafast Laser Laser ablation

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A REIntERPREtAtIOn OF tHE OLDESt HIMALAYAn FORELAnD BASIn SEDIMEntS: A REVISED AGE FOR tHE BALAKOt FORMAtIOn, PAKIStAn

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地学前缘 2000年第S1期7卷 310-312页

作者： Yani najman 1, Malcolm Pringle 2. Laurent Godin 3, Grahame Oliver 4[Wt5,5”BX](1 Foothills Research Project, department of Geology & Geophysics, university of calgary, {2. nW, calgary, Alberta t2. 1n4, canada,E\|mail: y.najman

the Balakot Formation foreland basin sediments, located in the Hazara\|Kashmir syntaxis, Pakistan, consist of a >8km thick succession of clastic red beds and calcrete, interpreted as deposited in a tidal environment. Within this sequence are intercalated four distinct grey fossiliferous marl and silt units, 2.～60m thick, dated at Late Palaeocene to Mid Eocene (Bossart & Ottiger 1989). thus the Balakot Formation has been interpreted as the oldest continental foreland basin deposits and has been used to determine the timing of India\|Eurasia collision (Rowley 1996) which has implications for the degree of diachroneity of collision (Burbank et al. 1996; Uddin and Lundberg 1998) and rapidity of metamorphism (treloar 1997), to interpret the palaeotectonics and palaeogeography of the mountain belt (Critelli and Garzanti 1994; Pivnik and Wells 1996), understand the relationship between mountain belt evolution and exhumation processes (treloar et al. 1991) and construct models of foreland basin evolution and geometry (DeCelles et al. 1998; Burbank et al 1996).

关键词： Balakot Formation foreland basin muscovite, Ar\|Ar isotopic dating Pakistan Himalaya exhumation

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