properties of selected engineering materials
Báo cáo lâm nghiệp: " A contribution to the properties of combined plywood materials" ppsx
Ngày tải lên :
07/08/2014, 04:20
... instead of spruce veneers in the whole construction of plywoods The density of plywoods significantly affects the capacity of the material to dampen noise To achieve good sound-proof properties materials ... Determination of sound-proof properties will be the subject of next research The quality of gluing was satisfactory, the disturbance of test specimens occurred always in the layer of cork because ... Werkstoff, 54: 377–382 Hrázský J., Král P., 2004 Analysis of properties of boards for concrete formwork Journal of Forest Science, 50: 382–398 Hrázský J., Král P., 2005 Effects of the thickness of...
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Báo cáo lâm nghiệp: "End-use related physical and mechanical properties of selected fast-growing poplar hybrids (Populus trichocarpa × P. deltoides)" potx
Ngày tải lên :
07/08/2014, 16:21
... related properties of poplar wood 627 Table VI Density (kg/m3 ), modulus of elasticity and modulus of rupture (N/mm2 ) for a 7-layer plywood for each of the selected clones Beaupré Density of the ... knot-free specimens were loaded at the centre at a rate of mm per in order to reach a duration of the test of 300 ± 120 s Of each stem, two logs of 2.6 m were peeled using industrial equipment to ... surface proportion of an individual zone of 6.25% The distribution of ‘Beaupré’ indicates that this clone has a bigger amount of smaller individual tension wood areas (85% of the tension wood...
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Structure, magnetic and transport properties of magnetic oxide materials and exploration of magnetic oxides semiconductor (zno) heterostructures
Ngày tải lên :
09/09/2015, 10:15
... supervisor Prof Ding Jun in Materials Science and Engineering Department (MSE) of National University of Singapore (NUS) for his guidance, inspiration, and encouragement throughout the course of my ... dependent transport properties of magnetic oxide materials with a high degree of spin polarization A research into the unique properties of magnetic oxides is one of the most important issues for ... of peak (311); 80 Figure XRD spectra of the CoFe2O4 films with a thickness of 100nm deposited at different temperature on glass substrates 84 Figure XRD spectra of the CoFe2O4...
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Electrical, magnetic and magnetocaloric properties of selected b site substituted manganites
Ngày tải lên :
09/09/2015, 17:53
... MAGNETOCALORIC PROPERTIES OF SELECTED B-SITE SUBSTITUTED MANGANITES SURESH KUMAR VANDRANGI (M Phil., University of Hyderabad, Hyderabad, India) A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY ... electrical and structural properties of Pr0.6Ca0.4Mn0.96B0.04O3 -56 3.7 Magnetocaloric properties of Pr0.6Ca0.4Mn0.96B0.04O3 60 3.8 DC magnetic properties of Pr0.6(Ca, Sr)0.4Mn1-xCrxO3 ... DC electrical properties of Pr0.6(Ca, Sr)0.4Mn1-xCrxO3 -75 3.10 Magnetocaloric properties of Pr0.6(Ca, Sr)0.4Mn1-xCrxO3 77 3.11 DC magnetic properties of Pr0.5Ca0.5Mn1-xRuxO3...
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Electrical, magnetic and thermal properties of selected perovskite oxides
Ngày tải lên :
10/09/2015, 09:11
... development of new materials for the improvement of GMI properties [58, 59, 60] 21 Introduction Figure 1.12: (a)The definition of the impedance of a current carrying conductor (b) Schematic diagram of ... figure -of- merit PF Power factor xxiii Introduction Chapter Introduction Transition metal oxides form an amazing class of materials with a wide range of properties They exhibit a variety of phenomena ... between the sets of energy states is called the crystal field energy which is of the order of eV [1] The ratio of dopant atoms Introduction at the site determines the valency of the Mn (Mn3+/Mn4+)...
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Electrical, dielectric and magnetocaloric properties of selected a and b site substituted manganites
Ngày tải lên :
10/09/2015, 15:52
... MAGNETOCALORIC PROPERTIES OF SELECTED A- and B-SITE SUBSTITUTED MANGANITES SUJIT KUMAR BARIK (M Tech., Indian Institute of Technology, Kharagpur, India) A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY ... 3.3.5 Discussions of dc electrical and magnetic properties 77 3.3.6 Magnetocaloric Properties of x ≤ 0.4 -81 3.3.7 AC Magnetoimpedance properties of x = 0.1 and 0.2 ... 127 4.3.4 Magnetocaloric properties of x ≤ 0.2 129 4.3.5 Magnetoimpedance properties of x ≤ 0.15 -130 4.3.6 Dielectric properties of x ≥ 0.3 ...
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Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 1 doc
Ngày tải lên :
11/08/2014, 14:20
... Conductivity of Metals? • Drude model: Sea of electrons – all electrons are bound to ion atom cores except valence electrons – ignore cores – electron gas Schematic model of a crystal of sodium ... Chemoresistor Photoconductor Magnetoresistor © H.L Tuller-2001 Origin of Conduction Range of Resistivity Why? 3.225 © E.A Fitzgerald-1999 Response of Material to Applied Potential I I V V=f(I) Rectification, ... from electric force on electron! 3.225 © E.A Fitzgerald-1999 Equation of Motion - Impact of Collisions Assume: • probability of collision in time dt = dt/τ • time varying field F(t) v(t+dt) = (1-...
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Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 5 ppt
Ngày tải lên :
11/08/2014, 14:20
... Fermi level is approximately in the middle of the band gap • The law of mass action describes the electron and hole populations, since the total number of electron states is fixed in the system ... oscillator, get: Ψ Ψdx * hω k x2 = E = e hω kT −1 Average energy of harmonic oscillator 3.225 © E Fitzgerald-1999 22 11 Estimate of T dependence of conductivity k x = E = hω hω e kT − hω = kθ kθ E = θ ... the barrier NCNV is the density of the reactants, and n and p are the products N C NV → e′ + h • Eg − Eg n np =ekT = i N C NV N C NV b • • • Thus, a method of changing the electron or hole...
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Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 10 pps
Ngày tải lên :
11/08/2014, 14:20
... Electrode ∆f Resonator Electrode 3.225 © H.L Tuller-2001 23 Choice of Piezoelectric Materials • Temperature limitations of piezoelectric materials Material Max Operating Limitations o Temperature ( ... Features: • materials versatility e.g Si, SiC, Ge, GaAs, GaN, etc • precise dimensional control down to 0.1 mm through the use of highly selective p-n junction etch-stops • fabrication of structures ... 3.225 © H.L Tuller-2001 Schematic Cross Section of Mounted Sensor 3.225 © H.L Tuller-2001 10 Resistance Response to Gas Environment Schematic of Gas Sensor Structure ZnO(Ar:O2=7:3) M 9710746...
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Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 9 pps
Ngày tải lên :
11/08/2014, 14:20
... Measurement of Gas Sensor Performance • Gas sensing materials: Sputtered ZnO film (150 nm (Massachusetts Institute of Technology) Sputtered SnO2 film (60 nm) (Fraunhofer Institute of Physical ... stability … 3.225 23 Sensor Materials Chemical Environmental Stimulus Gas Sensor Electrical Signal compatible with Microprocessor System Requirements of Gas Sensor Materials • • • • • • • • 3.225 ... semiconducting oxide Exhaust pO2 U I Electrode 3.225 © H.L Tuller-2001 Influence of Dopants on Electrical Conductivity of SrTiO3 log(σ / (Ωcm)-1 ) λ 0.995 1,005 T = 800 °C no -1 ac -2 ce pto -3 rd...
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Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 3 pot
Ngày tải lên :
11/08/2014, 14:20
... ψψ *dV = probability of finding particle in volume dV Average or expectation value of variable α = ∫ ψ *α op ψ dV v 3.225 © H.L Tuller-2001 19 Time and Spatial Dependence of ψ Assume ψ (x,y,z,t) ... L π h k πh N= g(E)=density of states=number of electron states per energy per length n= • • N 2k F 2mEF nπ = = or k F = π hπ L n, the electron density, the number of electrons per unit length ... velocity of the highest occupied electron state at T=0 3.225 © E Fitzgerald-1999 Representation of E,k for 2-D Material E= h (k x2 + k y ) E(kx,ky) 2m ky kx 3.225 © E Fitzgerald-1999 Representation of...
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Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 6 pps
Ngày tải lên :
11/08/2014, 14:20
... achieved where diffusive flux of the carriers is balanced by the drift flux 3.225 © E Fitzgerald-1999 12 Joining p and n p n Ec EF Ev Carriers flow under driving force of diffusion until EF is flat ... eVbi k bT n p = nn e − eVbi k bT © E Fitzgerald-1999 Qualitative Effect of Bias • • • Applying a potential to the ends of a diode does NOT increase current through drift The applied voltage upsets ... voltage upsets the steady-state balance between drift and diffusion, which can unleash the flow of diffusion current “Minority carrier device” np eVbi nn pp eVbi pn n p = nn e − e (Vbi −Va ) k...
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Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 8 pdf
Ngày tải lên :
11/08/2014, 14:20
... the ground state of a chromium atom (A) and a trivalent chromium ion (B) 3.225 © H.L Tuller, 2001 10 Octahedral Environment of Transition Metal Ion Interaction of the d orbitals of a central ion ... of positive and negative ions 3.225 © E Fitzgerald-1999 © H.L Tuller, 2001 Ferroelectrics Applications • Capacitors • Non-volatile memories • Photorefractive materials 3.225 Characteristics of ... has ∆λ parts of pulse with different l propagate at different speeds Black wave arrives later than red wave y n1 Solution: grade index n2 n 3.225 © E Fitzgerald-1999 Characteristics of Optical...
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Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 4 pps
Ngày tải lên :
11/08/2014, 14:20
... R hybridization © E Fitzgerald-1999 18 Properties of non-free electrons • Electrons near the diffraction condition are not approximated as free • Their properties can still be viewed as free ... band minimum at k=0: Direct Band Gap 3.225 © E Fitzgerald-1999 15 Review of H atom ψ = R(r )Θ(θ )Φ (φ ) Hψ = Eψ Do separation of variables; each variable gives a separation constant φ separation ... the periodicity of the lattice Ψ (r ) = e ik ⋅r u (r ) u (r ) = u (r + R ) Note the probability density spatial info is in u(r): Ψ *Ψ = Ψo u * (r ) ⋅ u (r ) An equivalent way of writing the Bloch...
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Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 11 potx
Ngày tải lên :
11/08/2014, 14:20
... induction, “softer” Magentic anisotropy hardness of loop dependent on crystal direction comes from spin interacting with bonding 3.225 © E Fitzgerald-1999 Domains in Ferromagnetic Materials B ... Fe, Ni, Co -> J positive! Other elements J is negative Rule of Thumb: interatomic distance r ≡ > 2ra 2(atomic radius) J is a function of distance! 3.225 © E Fitzgerald-1999 Ferromagnetism M M (T ... +10-5-10-4 Diamagnetic -10-8-10-5 Ferromagnetic +105 3.225 © E Fitzgerald-1999 Microscopic Source of Magnetization • No monopoles • magnetic dipole comes from moving or spinning electrons Orbital...
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Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 2 pot
Ngày tải lên :
11/08/2014, 14:20
... Example: Conductivity Engineering • Scaling of Si CMOS includes conductivity engineering • One example: as devices shrink… – vertical field increases ... p0 = p0 − eE τ ω>>1/τ, p out of phase with E eE0 p0 = iω − τ eE0 iω ω → ∞, p → ω1/τ) p p (ω
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Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 7 pptx
Ngày tải lên :
11/08/2014, 14:20
... susceptibility All detail of material response is in εr and therefore P 3.225 © E Fitzgerald-1999 Origin of Polarization • • • We are interested in the true dipoles creating polarization in materials (not ... So polarization slows down the velocity of the wave in the material © E Fitzgerald-1999 Compare Optical (index of refraction) and Electrical Measurements of ε Material Optical, n2 Electrical, ε ... Frequency Response of Materials • Bound charge can create dipole through charge displacement • Hydrodynamic equation (Newtonian representation) will now have a restoring force • Review of dipole physics:...
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Static properties of granular materials Philippe Claudin
Ngày tải lên :
01/11/2013, 08:20
... a series of captors), and are thus much noisier 250 Static properties of granular materials F r p h z Fig 14.13 Sketch of the experimental set-up of Reydellet et al for the measure of the pressure ... contact with 246 Static properties of granular materials typically hundreds of grains We start with a review of such experiments performed in different situations (geometry of the pile, the silo ... probably one of the issues that has been at the origin of the interest of many physicists for granular materials [359] The last point of this subsection will be dedicated to the study of the stress...
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Tài liệu Mechanical Properties of Engineered Materials P2 pptx
Ngày tải lên :
23/12/2013, 00:15
... and 2.8(f) These may be thought of as the absence of a plane of atoms (intrinsic stacking faults) or the insertion of rows of atoms that disturb the arrangement of atoms (extrinsic stacking faults) ... will be followed by a simple description of phase nucleation and grain growth The kinetics of phase nucleation and growth and growth in selected systems of engineering significance will be illustrated ... time-dependent flow of materials at temperatures greater than $0.3–0.5 of the melting temperature in degrees Kelvin Also, the activation energy, Q, in Eq (2.10) is indicative of the actual mechanism of diffusion,...
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Tài liệu Mechanical Properties of Engineered Materials P1 pptx
Ngày tải lên :
23/12/2013, 00:15
... mechanical properties of materials It is not intended to be a comprehensive review of all the different aspects of mechanical properties; such a task would be beyond the capabilities of any single ... classes of materials Following a brief introduction to materials science and basic strength of materials, the fundamentals of elasticity and plasticity are presented, prior to a discussion of strengthening ... extended to Prof Tom Eager and Prof Nam Suh of MIT for inviting me to spend a sabbatical year as Visiting Martin Luther King Professor in the departments of Materials Science and Engineering and...
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