nanoscale materials definition and properties

... Andreas Öchsner Lucas F M da Silva Holm Altenbach • Editors Mechanics and Properties of Composed Materials and Structures 123 Editors Andreas Öchsner Department of ... increment and n is the time step; unþ1 _ _ and unþ1 are assumed, unþ1 and unþ1 are corrected values of displacement and velocity; b and c are parameters that determine the stability and accuracy ... Mechanics and Properties of Composed Materials and Structures, Advanced Structured Materials 31, DOI: 10.1007/978-3-642-31497-1_2, Ó Springer-Verlag Berlin Heidelberg 2012 35 36 M M Kheirikhah and...

Ngày tải lên: 16/03/2014, 22:20

... How Do We Arrive at Properties That We Want? • Crystal Structure: • diamond vs graphite • Composition • silicon vs germanium ... electrons crossing plane in time dt = n(dxA) = n(vddtA) • # charges crossing plane per unit time and area = j ( ) j = n v d dtA (− e ) dtA = − nevd = (ne 2τ m )E • Ohm’s Law: j = σ E ⇒ σ = (ne ... Tuller-2001 13 Predicting Conductivity using Drude ntheory from the periodic table (# valence e- and the crystal structure) ntheory=AVZρm/A, where AV is 6.023x1023 atoms/mole ρm is the density...

Ngày tải lên: 11/08/2014, 14:20

... E F =  m*   * + kbT ln h   me  Eg Since me* and mh* are close and in the ln term, the Fermi level sits about in the center of the band gap ( ) − Eg  k T 2 * * p or n = ni = 2 b  me ... are generated, the 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 ... similar to a chemical reaction, where Eg is 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,...

Ngày tải lên: 11/08/2014, 14:20

... sensing a change in environment and responding without need for a microprocessor A device has both gas sensing and actuating function by integration of semiconducting oxide and piezoelectric thin films ... Chemically inert • Abrasion resistant Wide band gap semiconductor/insulator 3.225 © H.L Tuller-2001 17 Photo Electro-chemical Etching - PEC Features: • materials versatility e.g Si, SiC, Ge, GaAs, ... film Gas flow / sccm • ZnO film (150 nm) 80 time / h Temp:360C, H2, CO, NH3 (10, 50 and 100 ppm), NO2 (0.2, 0.4, and ppm) [ Pfad: \ alpha missy Messungen messplatz_1 ] 3.225 M Jägle / 27.02.2001...

Ngày tải lên: 11/08/2014, 14:20

... (Pb0.98La0.02(Zr0.7Hf0.3)1-xTixO3 AFE­ FE System (C Heremans and H.L Tuller, J Euro Ceram Soc., 19, 1139 (1999).) Atmosphere dependent conductivity (I Kosacki and H.L Tuller, Sensors & Actuators B 24-25, 370 ... stability … 3.225 23 Sensor Materials Chemical Environmental Stimulus Gas Sensor Electrical Signal compatible with Microprocessor System Requirements of Gas Sensor Materials • • • • • • • • 3.225 ... microprobe Probes 15µm thick 2-4mm long (Najafi and Hetke, IEEE Trans Biomed Eng 37, 474 (1990).) 3.225 28 14 Measurement of Gas Sensor Performance • Gas sensing materials: Sputtered ZnO film (150 nm (Massachusetts...

Ngày tải lên: 11/08/2014, 14:20

... absorb energy and contribute to properties TF~104K (Troom~102K), EF~100Eclass, vF2~100vclass2 3.225 © E Fitzgerald-1999 Effect of Temperature (T>0): Coupled electronic-thermal properties in conductors ... 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) separable into ψ(x,y,z) and φ(t) Applying separation of variables: − h ∇ 2ψ h ∂φ +V ... Model Traveling wave picture L Standing wave picture Ψ ( x) = Ψ ( x + L) L e ikx = e ik ( x + L ) e ikx = 2πn k= L Just having a boundary condition means that k and E are quasi-continuous, i.e...

Ngày tải lên: 11/08/2014, 14:20

... Means to Create Internal Potentials: Heterojunctions • Different semiconductor materials have different band gaps and electron affinity/work functions Internal fields from doping p-n must be superimposed ... Joining p and n p n Ec EF Ev Carriers flow under driving force of diffusion until EF is flat - - + + + + Holes diffuse Electrons diffuse 3.225 © E Fitzgerald-1999 13 Space Charge, Electric Field and ... increases depletion region, and no current flows ideally Forward Bias Reverse Bias np np eVbi-e|Va| nn nn eVbi-e|Va| pp Solve minority carrier diffusion equations on each side and determine J at depletion...

Ngày tải lên: 11/08/2014, 14:20

... Fiber 3.225 Colors Produced by Chromium Above: alexandrite, emerald, and ruby Center: carbonate, chloride, oxide Below: potassium chromate and ammonium dichromate 3.225 © H.L Tuller, 2001 Chromium ... five 3d orbitals in a tetrahedral and an octahedral ligand field Note: When the element is a mid-gap dopant, transitions within this element lead to absorption and/ or emission via luminescence ... electronic and orientational polarizability ε r = + χe + χo = n2 + N α DC 3ε o (1 − iωτ ) ωτ

Ngày tải lên: 11/08/2014, 14:20

... promoted from the valence band to the conduction band E Ec near band gap E=hν k Creates a ‘hole’ in the valence band Ev near band gap 3.225 © E Fitzgerald-1999 Holes and Electrons • • Instead ... 1,000,000 Remember that: 3.225 µ= eτ m* and 1 ∂2E = m * h ∂k 2 Metals and Insulators • EF in mid-band area: free e-, metallic • EF near band edge – EF in or near kT of band edge: semimetal – EF in gap: ... ionic, MP and Eg increase while ao tends to decrease 3.225 © H.L Tuller-2001 Trends in III-V and II-VI Compounds Larger atoms, weaker bonds, smaller U, smaller Eg, higher µ, more costly! Band Gap...

Ngày tải lên: 11/08/2014, 14:20

... MKS: B = µ0(H+M) = µ0nI + µ0M µr = B/ µ0H = + (M/H) = + χm 3.225 © E Fitzgerald-1999 Maxwell and Magnetic Materials • Ampere’s law ∫ H ⋅ dl = I = • For a permanent magnet, there is no real current ... I A L e- What is µ? For θ=0, E = − µH ≈ −Φ B I since energy ~ LI and for loop L = ΦB I Φ B = ∫ ∫ H ⋅ dS ~ HA ∴ µH = Φ B I = HAI and ∴ µ = IA e ω A = πr c 2π e µ = − ωr 2c I =− 3.225 © E Fitzgerald-1999 ... Magnetic Materials • The inductor Φ B = LI (Q = CV) ∂B (CGS) c ∂t ∂ ∂Φ ∫ ∫ ∇ × EdS = − c ∂t ∫ ∫ BdS = − c...

Ngày tải lên: 11/08/2014, 14:20

... Hall Results on Metals • Valence=1 metals look like free-electron Drude metals • Valence=2 and 3, magnitude and sign suggest problems 3.225 © E.A Fitzgerald-1999 25 13 Response of Free e- to AC Electric ... Fitzgerald-1999 Complex Representation of Waves sin(kx-ωt), cos(kx-ωt), and e-i(kx-ωt) are all waves e -i(kx-ωt) is the complex one and is the most general imaginary A θ Acosθ iAsinθ real e iθ=cosθ+isinθ ... (ω>>1/τ) p p (ω

Ngày tải lên: 11/08/2014, 14:20

... 80.4 Electronic, ionic, and molecular polarisation Polarization that is active depends on material and frequency 3.225 © E Fitzgerald-1999 Microscopic Frequency Response of Materials • Bound charge ... polarization (E-field may distort ion positions and temporarily create dipoles) – electronic polarization (bound electrons around ion cores could distort and lead to polarization) • • Except for the ... E-M waves travel in insulating materials: What is the response of the material (εr) to these waves? 3.225 © E Fitzgerald-1999 Wave Eqn with Insulating Material and Polarization r r ∂B ∇xE = −...

Ngày tải lên: 11/08/2014, 14:20

... the new properties list, the value for the key from the defaults set will be returned 64 Using Properties public Properties( ) public Properties( Properties defaults) Instances of the Properties ... VARIABLE/METHOD NAME Properties( ) getProperty() VERSION 1.0 1.0 DESCRIPTION Constructs a properties list Retrieves a value for a key in the properties list list() 1.0 Lists all the properties and their ... primary tasks of working with properties are setting and getting You can also load them from an input stream or save them to an output stream Setting and Getting Elements The Properties class has a...

Ngày tải lên: 05/10/2013, 12:20

... stained urethral discharge The image shows many polymorphonuclear leukocytes (PMNs) and gram-negative extra- and intra-cellular diplococci (1,000X oil) Pneumococci in sputum Other important bacteria ... components 1: (endo)spores usually Bacillus spp and Clostridium e.g Clostridium tetani (tetanus) spore is a resting cell, highly resistant to desiccation, heat and chemical agents produced in response ... Flagella Flagellum can be removed but is rapidly replaced  Involved in motility and impart spinning movement and usually requires proton motive force  Chemotaxis: flagella move bacteria towards...

Ngày tải lên: 12/12/2013, 17:15

Ngày tải lên: 18/02/2014, 11:20

... for the first time, purification and properties of a tungsten-containing NAD-dependent FDH from the aerobic bacterium, M extorquens AM1 Materials and methods Organism and growth conditions M extorquens ... enzymes (FDH1, FDH2 and FDH3) FDHH from E coli was studied in detail biochemically and crystal structures of the enzyme are known [34] The enzyme contains selenocysteine, molybdenum and two molybdopterin ... Haloferax volcanii and Methanothermobacter thermautotrophicus, and a function was suggested for these genes in the specific uptake of Fig Emission fluorescence spectra of purified FDH1 and milk xanthine...

Ngày tải lên: 20/02/2014, 23:20

... amyloliquefaciens and primers V1, V2, and V3 (Table 2) for regions MKKRFWFLA, VFIDYKVEG, and IVGVISDAE of the B subtilis SipV protein were chosen and found to generate PCR fragments of about 0.5 and 0.4 ... amyloliquefaciens, and to evaluate differences in functions after genetic complementation in an E coli LepBts mutant and after construction of B amyloliquefaciens sip(ba) gene disruption mutants MATERIALS AND ... genomic DNA of B amyloliquefaciens and the degenerative primers V1/V3 and V2/V3 or W1 and W2, led to the isolation of core DNA fragments of about 0.5 kb (lane b) and 0.4 kb (lane c), or 0.2 kb,...

Ngày tải lên: 21/02/2014, 03:20

... metals and alloys, ceramics and glasses, and polymeric materials (Chapter 3) • Failure mechanisms in cellular-sandwich materials due to blast (Chapter 3) • Current capabilities for modeling and ... shoot -and- look mode is much more common In addition, the materials research and development community and the modeling and simulation community are not particularly well connected materials and ... Understanding of Mechanisms of Deformation and Failure Due to Ballistic and Blast Threats, 102 Element 2—Advanced Computational and Experimental Methods, 102 Element 3—Development of New Materials and...

Ngày tải lên: 05/03/2014, 12:20

... and 12 b strands (b112) as secondary structural elements; it also has a Greek key motif with seven anti-parallel b strands (Figs and 2A), which is also found in DvMF FMN-binding protein [7] and ... bonds and salt bridge that encompass the ribitol moiety and the phosphate group of FeR and M acetivorans avoredoxin are moderately and completely conserved in DvMF avoredoxin (Fig 3A,B and Fig ... different in both FeR and M acetivorans avoredoxin These cysteine residues are replaced by threonine and leucine in FeR and asparagine and valine in M acetivorans avoredoxin (Figs and 3D; Fig S4C)...

Ngày tải lên: 07/03/2014, 02:20

... this work was to purify and characterize tetrathionate hydrolase from A caldus The products of the enzymatic reaction were also determined Materials and methods Bacteria and growth conditions A ... Vibra Cell (Sonics & Materials Inc., Danbury, CT, USA) and cell debris was 274 Z Bugaytsova and E B Lindstrom (Eur J Biochem 271) ¨ removed by centrifugation at 10 000 g for 10 and the activity of ... concentrated by Centriprep Centrifugal Filter YM-3, and resolved by SDS/PAGE One major band with a molecular mass of 54 kDa and a few faint bands with molecular mass < 40 kDa were also detected...

Ngày tải lên: 07/03/2014, 14:20