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  • 1
    Electronic Resource
    Electronic Resource
    Electrical resistivity and Hall effect of TiSi2 thin films in the temperature range of 2–300 K (1989)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 5416-5421 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The electrical resistivity and Hall effect of TiSi2 thin films were measured systematically in the temperature range of 2–300 K. The results were compared with theory and other work. The TiSi2 films were formed by Ti/Si solid-state interaction on crystalline silicon or polysilicon substrates. The temperature dependence of the electrical resistivity of TiSi2 was approximated by the Bloch–Gruneisen theory. The Hall-effect data show a multicarrier conduction mechanism in TiSi2. At low temperatures the Hall coefficient is positive for both substrates, but is negative at room temperature. The temperature at which the change of sign occurs is approximately 180 K for the crystalline-Si substrate, and approximately 90 K for the polysilicon substrate. This is discussed briefly in terms of scattering mechansims for a simple model of the electronic structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.343689
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  • 2
    Electronic Resource
    Electronic Resource
    Perceptions of positive and negative factors influencing the attractiveness of PPP/PFI procurement for construction projects in the UK: Findings from a questionnaire survey (2005)
    Oxford : Emerald
    Engineering, construction and architectural management 12 (2005), S. 125-148 
    Details
    ISSN: 1365-232X
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Purpose - The paper aims to report the findings of research into perceptions of what makes the Private Finance Initiative (PFI) attractive or unattractive as a procurement system for projects in the UK. Design/methodology/approach - The research uses a postal survey questionnaire technique for primary data collection. Literature review is used to identify relevant factors, which are then incorporated into the design of the survey instrument. Survey response data is subjected to descriptive statistical analysis and subsequently to rotated factor analysis. Findings - Public/private partnerships (PPP)/PFI project procurement is perceived as most attractive in terms of positive factors relating to better project technology and economy, greater public benefit, public sector avoidance of regulatory and financial constraints, and public sector saving in transaction costs. Negative aspects, relating to factors such as the inexperience of the participants, the over-commercialisation of projects, and high participation cost and time, make PPP/PFI procurement less attractive. Originality/value - The procurement of public facilities and services under arrangements involving partnerships between the public and private sectors is claimed to provide a wide variety of net benefits to the public sector and to the private sector participants. In the project development process, the parties have to make decisions based on suitable evaluation criteria. At the early stage of preparing a business case, a clear and common understanding of the positive and negative factors surrounding PPP/PFI procurement will provide a more informed basis for decision making.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/09699980510584485
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  • 3
    Electronic Resource
    Electronic Resource
    Stiffness Analysis for a Novel Parallel-Robot Based High-Precision Flexible Assembly Fixture (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 364-366 (Dec. 2007), p. 327-332 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In this paper, a novel parallel mechanism (3-RRRS/UPR) used in flexible fixture withconfiguration composed of two parallel robots (2-RR and 3-RRRS/ UPR) is presented. First, systemmodeling including the mobility study is conducted. Then a novel methodology is proposed thatmakes use of screw theory to analyze the deformation and stiffness of the mechanism: firstly weidentified the existence of the deformation of the subchain, in terms of the relationship between theeffective screw and deformation screw; then we took the deformation as an infinitesimal motion ofthe mechanism, and the stiffness matrix corresponding to the deformation can be deduced. Finallythe global stiffness matrix of the whole mechanism is modeled by assembling different stiffnesscharacters based on the presented methodology
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/56/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.364-366.327.pdf
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  • 4
    Electronic Resource
    Electronic Resource
    Post-Processing Development of a New PTS-X Hybrid Kinematics Machine (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 375-376 (Mar. 2008), p. 719-723 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A new 5-degrees-of-freedom hybrid kinematic machine(HKM) consisting of a4-degrees-of-freedom PTS-based parallel kinematics platform with center constraint branch and aserial X axis is developed. The will-be-machined workpiece is mounted on the platform and thespindle movement is driven by the X axis. This new HKM is very different from a conventionalserial-type machine. Therefore, a special algorithm that can transfer the cutter location data(CL-data) into machine specific NC commands is essential for the applications of the PTS-X basedHKM in real machining of the workpiece with the complicated surface. The workpiece’s locationapproach on the platform and the orientation transformation of the moving platform relative to themachine coordination system are investigated
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/57/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.375-376.719.pdf
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  • 5
    Electronic Resource
    Electronic Resource
    Study on the Composite Measuring Method for Small Module Gears (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 381-382 (June 2008), p. 83-86 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The detection technique of small module gears has a very important research andapplication value. In this paper, a composite measuring method is presented based on combiningtraditional mechanical contact measurement with optical image non-contact measurement. First ofall, this paper analyzes the basic principle of composite probe composed of optical fiber stylus andCCD imaging system. The tail-end of the stylus is shaped into a micro-sphere, where a smallrefection mirror is designed. When the laser is transmitted through the fiber, a round facula can beseen from the CCD camera. The micro-sphere is kept contact with the surface of the measured gearat the time of measuring and the error of the measured gear will be reflected by the offset of thefacula center. Meanwhile, the sub-pixel extraction algorithm for the center of facula image ispresented. Then the calibration principle and method of probe system is analyzed in detail. Finally,the data processing principle of the presented method is discussed for gear measurement
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/57/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.381-382.83.pdf
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  • 6
    Electronic Resource
    Electronic Resource
    Kinematics Calibration of Parallel Kinematic Machine Using a Developed Double-Ball Bar Gauge (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 364-366 (Dec. 2007), p. 243-248 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In this paper a novel constraint calibration technique for Stewart platform based ParallelKinematics Machine(PKM) is presented. A commercial trigger probe and a developed double-ballbar gauge are employed to aid the calibration. In the measuring process the characterized errors canbe obtained by comparing the nominal characterized size calculated by the function using themeasuring data with the real size of the double-ball gauge. An optimization approach is used tocalculate the PKM structural errors, and these errors can be finally compensated into the controlmodel. The error transferring matrix with regard to the structural error of PKM can be formulated.The calibration efficiency can be improved by the automatic calibration operation with the doubleballbar gauge. The developed calibration system has been applied in the industry where the PKM isused for machining the turbine vane, and the machining quality can meet the requirements of thespecifications. The presented calibration scheme is generic to be applied for the wide range ofPKMs
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/56/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.364-366.243.pdf
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  • 7
    Electronic Resource
    Electronic Resource
    An Empirical Approach for Identification of Sources of Machining Errors in Ultra-Precision Raster Milling (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 364-366 (Dec. 2007), p. 986-991 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Ultra-precision raster milling is one of the most significant techniques for the fabricationof high precision components with the surface roughness less than 10nm and form errors less than0.2 um, without the need for any subsequent polishing. However, no matter how well a machinemay be designed, there is a limit to the accuracy that can be achieved. This paper studies themachining errors caused by the diamond tool and the axis motions using Freeform 705G. With anempirical approach, the error sources are separated based on their effects on the surface finish. Themain source leading to poor surface finish is identified. This establishes a basis for subsequent errorcompensation and equipment maintenance
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/56/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.364-366.986.pdf
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  • 8
    Electronic Resource
    Electronic Resource
    Prediction of the Properties of an Alumina Green Body Using an Artificial Neural Network by a New PSO-Gain Backpropagation Algorithm (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 368-372 (Feb. 2008), p. 1642-1644 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Artificial neural networks have been successfully used in classification, formulation optimization,defect diagnosis and performance prediction in ceramic industry. However, an artificial neuralnetwork based on the traditional backpropagation (BP) algorithm showed some disadvantages in mappingthe nonlinear relationship between the composition and contents of the ceramic materials and theirproperties. In this paper, a new PSO-Grain (Particle Swarm Optimization Gain) BP algorithm wasintroduced, and an improved artificial neural network model was employed to predict the properties of analumina green body. The training performance of the neural network using the PSO-Gain BP algorithmwas analyzed and it was indicated the POS-Gain BP based neural network could reduce convergence tolocal minima and was more efficient than the traditional BP based network. The prediction accuracy ofthe properties such as linear shrinkage and bending strength using the PSO-Gain BP based neural networkwas higher than that of the BP based neural network
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/56/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.368-372.1642.pdf
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  • 9
    Electronic Resource
    Electronic Resource
    Study on the Phase Unwrapping Method with Colored Encoded Grating Pattern in 3-Dimension Profile Measurement (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 381-382 (June 2008), p. 275-278 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The phase-shifting method is widely used in 3-D profile measurement with optoelectronictechnology and phase unwrapping is an important link where in. The traditional methods are toocomplex and have low efficiency. A novel method of evaluating absolute phase is presented in thispaper. The technique combined the grey code fringe with phase shifting technique and coloredencoded grating pattern. The order of the projecting fringes ) , ( y x n can be obtained from only onedistortional colored image. The procedure is relatively simple in experimental setup and algorithm. Inaddition, the speed of measurement is faster than current phase unwrapping algorithm. Theexperimental results have proved the validity of this method
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/57/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.381-382.275.pdf
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  • 10
    Electronic Resource
    Electronic Resource
    Numerical Solution of Elas-Plastic Impact Load of Tube Column (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 33-37 (Mar. 2008), p. 363-368 
    Details
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The explicit numerical method is used to trace the impact procedure of the tube columnsimpacted by a rigid body. The bar and rectangle tube models are both used to simulate the tubecolumn. The elastic and elas-plastic impact load with different mass ratio and impact speed areobtained. The calculation results show that: for elastic models, the bigger the mass ratio and thehigher the rigid body speed, the bigger the peak value of elastic impact load; at the same time, themore obvious the reduction effect of local buckling of rectangle tube on the peak value of impact loadand the longer the contact time of tube model; so the peak value of impact load of the rectangle tube isnot proportional to the rigid body speed. The stress wave in the tube causes a little difference betweenthe load curves of tube model and bar model. For elas-plastic models, the higher the rigid body speedand the smaller the mass ratio, the bigger the peak value of impact load and the longer the contacttime. The higher the rigid body speed, the bigger the difference between elastic and elas-plasticimpact load peak value due to the expanding of plasticity. Because of the effect of local buckling, thepeak value of elas-plastic impact load of rectangle tube is always lower than that of bar
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/40/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.33-37.363.pdf
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