engineering materials and their properties
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 1 doc
... 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...
- 10
- 363
- 0
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 5 ppt
... 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,...
- 10
- 415
- 0
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 10 pps
... 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...
- 10
- 394
- 0
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 9 pps
... 19 Electroceramics Ceramics: • Traditionally admired for their stability • Mechanical • Chemical • Thermal • Exhibit other key functional properties • Electrical, Electrochemical, Electromechanical ... (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...
- 10
- 343
- 0
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 3 pot
... 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...
- 10
- 392
- 0
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 6 pps
... 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...
- 10
- 342
- 0
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 8 pdf
... 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
- 10
- 353
- 0
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 4 pps
... 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: ... 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...
- 10
- 292
- 0
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 11 potx
... 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...
- 6
- 347
- 0
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 2 pot
... Example: Conductivity Engineering • Scaling of Si CMOS includes conductivity engineering • One example: as devices shrink… – vertical field increases ... 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...
- 10
- 294
- 0
Materials Science and Engineering - Electronic and Mechanical Properties of Materials Part 7 pptx
... 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 = −...
- 10
- 277
- 0
classes of groups and their properties
... form(S) = D0 (S, 1) 92 Classes of groups and their properties If F and G are formations and F ∩ G = (1), then D0 (F ∪ G) = R0 (F ∪ G) Let ∅ = F be a formation and let S be a non-abelian simple group ... the first and third properties leading to the theory of saturated formations and Schunck classes and the associated projectors and the second property to the theory of Fitting classes and injectors ... X and an epimorphism from H onto G); Sn X = (G : G is subnormal in H for some H ∈ X); R0 X = G : there exist Ni G (i = 1, , r) r with G/Ni ∈ X and Ni = i=1 90 Classes of groups and their properties...
- 37
- 378
- 0
Báo cáo hóa học: " Hydrothermally Grown ZnO Micro/Nanotube Arrays and Their Properties" pptx
... micro/nanotubes show strong nearband-edge emission at 387 nm and weak defects-related emissions at 422 and 485 nm, respectively Contact angle result indicates they have good hydrophobic properties Field-effect ... nanowires has already been observed for several materials, such as ZnO and ZnS [13, 41] The crystal structure of the products was also investigated using XRD and the pattern is shown in Fig In this pattern, ... crystal planes and thus resulted in the formation of different structures To investigate the optical properties of these micro/ nanotubes, room-temperature photoluminescence was conducted and a typical...
- 6
- 262
- 0
Báo cáo hóa học: " Morphologies of Sol–Gel Derived Thin Films of ZnO Using Different Precursor Materials and their Nanostructures Harish Bahadur Æ A. K. Srivastava Æ R. K. Sharma Æ Sudhir Chandra" pdf
... that the films grown by zinc acetate and zinc nitrate as precursor materials show different morphological features Films grown by zinc nitrate show a rapid and random crystallization than the films ... random directions and thus give rise to dendrites or island type morphology of the film structure as shown in the set of micrographs in Fig The exact nature of morphology like dendrites or island, ... radians) and h is of course the Bragg angle The CuKa line has the ˚ average wavelength of 1.54178 A and consists of two lines ˚ CuKa1 and CuKa2 with CuKa1 at 1.5405 A with a shoulder ˚ band of...
- 7
- 397
- 0
COMPOSITES AND THEIR PROPERTIES ppt
... and scull hulls, sporting goods, sensor/actuator, catalysts and pollution processing materials, biomedical materials, and batteries, etc This book focuses on the fabrication, properties and their ... electronic and magnetic properties of Fe, Co and Ni adatoms adsorbed on a h-BC2 N sheet A hexagonal site at the interface between BN and graphene 14 12 Composites and Their Properties 3.5 Band Gap ... composites and hybrid materials Author details Mingchao Wang, Cheng Yan and Lin Ma School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University...
- 516
- 374
- 0
Engineering Materials and Processes phần 1 doc
... 978-1-84800-027-8 Engineering Materials and Processes ISSN 1619-0181 British Library Cataloguing in Publication Data Adams, Daniel Silver metallization : stability and reliability (Engineering materials and ... Microstructure of Steels and Cast Irons M Durand-Charre Phase Diagrams and Heterogeneous Equilibria B Predel, M Hoch and M Pool Computational Mechanics of Composite Materials M Kamiński Gallium ... Nitride Processing for Electronics, Sensors and Spintronics S.J Pearton, C.R Abernathy and F Ren Materials for Information Technology E Zschech, C Whelan and T Mikolajick Fuel Cell Technology N Sammes...
- 14
- 191
- 1
Engineering Materials and Processes phần 2 pptx
... San Jose, CA, 1994 J Li, J W Mayer, Y Shacham-Diamand, E G Colgan, Appl Phys Lett 60 2983(1992) D Adams, and T L Alford, Materials Science and Engineering: Reports 40, 207(2003) T Iijima, H Ono, ... Cu and due to the absence of any compound formation between Cu and Ta, and between Cu and N [5] Diffusion barriers are used to prevent degradation of devices as a result of poor adhesion and ... application in ICs because of their (a) high diffusivity and deep levels in silicon, (b) poor adhesion to SiO2 and polyimide, and (c) reactivity with the environment To make copper and silver metallization...
- 14
- 270
- 0
Engineering Materials and Processes phần 3 docx
... oxygen content and composition of the TaN films The 3.0 MeV and 3.7 MeV beam energies correspond to oxygen (O) and nitrogen (N) resonances, respectively, and were used to detect O and N The 3.0 ... Barriers 3.4.1 Introduction The properties of TaN films are extremely sensitive to film microstructure and morphology The chemical composition, microstructure, and properties of TaN films depend ... interconnect Ag metal and the underlying dielectric that will act as both an adhesion promoter and an effective diffusion barrier between interconnect metal and adjacent materials 3.4.2 Experimental...
- 14
- 322
- 0
Engineering Materials and Processes phần 4 pptx
... resistivity of materials depends on their purity and microstructure Impurities and structural imperfections such as grain boundaries, dislocations and vacancies contribute to electron scattering and hence ... leading edge of the silicon (Figure 3.12a and b), and the presence of Ta, Ag and Si at the surface The failure of the TaN barrier in contact with Ag and Si is driven predominantly by the large ... Abstracts Conf On Solid State Devices and Materials, Makuhari, 1993 D Adams, B A Julies, J W Mayer and T L Alford Thin Solid Films 332, 235(1998) A W Czandema, J Phys Chem 68, 2765(1964) T E...
- 14
- 432
- 0
Engineering Materials and Processes phần 5 pptx
... dielectric constant, the materials must have a good adhesion to silicon and to interconnect materials and thermal stability Thermal stability is important to device characteristics and reliability The ... resistivity interconnect materials, copper is being considered as a good candidate However, copper diffuses very fast in different materials Hence, the lower resistivity and relatively noble metal, ... silver, is considered here Gadre and Alford [7] investigated Parylenen (Pa-n) and silver for ultra large scale integrated circuits because of their favorable properties These include low dielectric...
- 14
- 245
- 0
Tìm thêm: xác định các mục tiêu của chương trình khảo sát chương trình đào tạo của các đơn vị đào tạo tại nhật bản xác định thời lượng học về mặt lí thuyết và thực tế điều tra đối với đối tượng giảng viên và đối tượng quản lí điều tra với đối tượng sinh viên học tiếng nhật không chuyên ngữ1 khảo sát thực tế giảng dạy tiếng nhật không chuyên ngữ tại việt nam khảo sát các chương trình đào tạo theo những bộ giáo trình tiêu biểu nội dung cụ thể cho từng kĩ năng ở từng cấp độ xác định mức độ đáp ứng về văn hoá và chuyên môn trong ct phát huy những thành tựu công nghệ mới nhất được áp dụng vào công tác dạy và học ngoại ngữ mở máy động cơ lồng sóc mở máy động cơ rôto dây quấn các đặc tính của động cơ điện không đồng bộ hệ số công suất cosp fi p2 đặc tuyến hiệu suất h fi p2 đặc tuyến tốc độ rôto n fi p2 đặc tuyến dòng điện stato i1 fi p2 động cơ điện không đồng bộ một pha sự cần thiết phải đầu tư xây dựng nhà máy chỉ tiêu chất lượng theo chất lượng phẩm chất sản phẩm khô từ gạo của bộ y tế năm 2008