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Electromagnet Fundamentals
Published in David A. Cardwell, David C. Larbalestier, Aleksander I. Braginski, Handbook of Superconductivity, 2022
The provenance of this equation can be found, for example, in Montgomery [4] and we will not dwell on it here except to say that for a winding of constant current density, a packing factor of 0.7 (low but water cooling channels have to be allowed for), a bore of radius 2.5 cm and using the most efficient value of G(α, β) = 0.179, We find that for a B0 of 10 tesla (T), we require 1.9 MW of power. This assumes a copper resistivity of 1.7 × 10−6 Ω cm at 20°C. In fact, it is more likely that the copper will be somewhat hotter, say, 70°C in which case ρ will be 2.05 × 10−6 Ω cm and the power requirement then will be 2.3 MW. Just to emphasise the point, 10 T, by no means a high field in absolute terms, requires the power that would satisfy the domestic requirements of some hundred houses—a typical village.
Simultaneously Evaporated Al-Doped Zn Films for Optoelectronic Applications
Published in Devrim Balköse, Ana Cristina Faria Ribeiro, A. K. Haghi, Suresh C. Ameta, Tanmoy Chakraborty, Chemical Science and Engineering Technology, 2019
Yasir Beeran Pottathara, Obey Koshy, M.A. Khadar
The dc resistance of 2AZO and 6AZO films was carried out in the temperature range from 300 to 450 K, as shown in Figure 8.7(a) and (b). The average thickness was found to be 1000 Å and 1200 Å for the 2AZO and 6AZO samples, respectively. Generally, various factors including concentration of dopants, oxygen vacancies, material composition, and grain boundaries are influencing the resistivity of a material.30 The decreased electrical resistivity with increased temperature indicates the semiconducting behavior of AZO films. It may be attributed that the increment of Al content may cause the substantial drop of carrier concentration and hall mobility.31 The increased electrical conductivity of 2AZO film sample was due to the better crystallinity and dense structure which can trap more free electrons compared with 6AZO film sample.32 Sometimes, the highest amount of doping can reduce the carrier mobility and thus increases the electrical resistivity.33
Copper Interconnects for Ceramic Substrates and Packages
Published in Fred D. Barlow, Aicha Elshabini, Ceramic Interconnect Technology Handbook, 2018
Of all the metals used for interconnections on electronic packages and substrates, copper has the second lowest electrical resistivity at 1.72 × 10−6 Ω⋅cm. Silver, with a resistivity of 1.59 × 10−6 Ω⋅cm [1], has the lowest resistivity but suffers from the potential problem of silver migration [2]. This low resistivity (or high conductivity) makes copper the second highest on a volume basis. For low-current applications where high interconnect density is required, this equates to a higher density of interconnections. Low electrical resistivity is a key parameter in determining efficiency and propagation delay. The electrical resistivity of a conductor also determines the amount of self-heating. Therefore, to minimize self-heating, the conductor’s resistivity needs to be minimized.
Physical and electrical properties’ evaluation of SnS:Cu thin films
Published in Surface Engineering, 2021
S. Sebastian, I. Kulandaisamy, S. Valanarasu, Mohd Shkir, V. Ganesh, I. S. Yahia, Hyun-Seok Kim, Dhanasekaran Vikraman
Hall Effect measurements were performed to evaluate electrical properties with respect to dopant concentration. Figure 5(a) shows resistivity with respect to dopant concentrations for SnS:Cu thin films, confirming p-type conductivity. Resistivity = 0.257 × 102 and 2.8 × 10−2 Ω.cm for 2 and 6 wt-% dopant concentration, respectively; whereas 8 wt-% concentration produced maximum resistivity = 0.436 × 102 Ω.cm. Figure 5(b,c) show carrier mobility and concentration variations, respectively. Similar to resistivity, carrier concentration and Hall mobility increased from 2.816 × 1016 to 1.141 × 1019 cm−3 and from 8.615 to 19.380 cm2.V−1s−1 for 2 and 6 wt-% dopant concentrations, respectively. This increase is attributed to Cu ion substitution into Sn ion sites, increasing carrier density in the valence band, hence increasing acceptor sites and leading to minimum resistance at room temperature.
Finishing performance of die-sinking EDM with ultrasonic vibration and powder addition through pulse train studies
Published in Machining Science and Technology, 2020
The die-sinking EDM is capable of machining complex and intricate shapes on hardened die steel. D3 die steel is taken as the work material in this work, since it is used for making molds as well as dies. The chemical composition of D3 die steel as determined using an optical emission spectrometer (SpectroLab M8, Germany) is listed in Table 1. Electrical resistivity of D3 die steel is 0.65(10−6) Ωm. The work material is cut in its annealed condition into cubes having a side of 20 mm. Since die-sinking is done in the hardened condition, heat treatment is carried out following the industrial practice. The samples are heated in steps of 100 °C to reach a temperature of 1000 °C after 10 h. The specimens are then quenched in a salt water bath for 14 h duration. The final hardness of samples achieved is in the range of 55–58 HRC. All the six faces of the samples are fine ground using a surface grinder. A cylindrical rod of 10 mm diameter made of electrolytic copper (99.9% pure) is used as a tool electrode. Its electrical resistivity is 1.72(10−8) Ωm. The Electronica ZNC EDM machine with DC pulse generator available in a die and mold manufacturing industry is used to conduct the experiments. The relevant specifications of the machine are listed in Table 2. The dielectric fluid is EDM oil supplied with the machine. It is a proprietary brand of oil from the machine manufacturer.
Micro electrical discharge milling of a monocrystalline silicon complex micro-cavity
Published in Materials and Manufacturing Processes, 2022
Sirui Gong, Han Wang, Chuan Tian, Zhenlong Wang, Yukui Wang
In this study, monocrystalline silicon was used as the workpiece material, and some physical and mechanical properties of silicon were shown in Table 1. The p-type silicon, doped boron element with 1015–1016 per cubic centimeter, was selected as the material. The resistivity is 1–10 Ω∙cm. Wafer thickness is 2 mm with a tolerance of 10 μm. The surface roughness is less than 0.2 nm. The silicon wafer was cut into pieces with the length of 15 mm, the width of 2 mm and the thickness of 2 mm by WEDM. The tool electrode for micro electrical discharge milling was made of a high-purity tungsten rod with the diameter of 0.5 mm, dressed the tool electrode by standard block electrode which is made of tungsten-copper alloy.