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The Printed Wiring Board (PWB) in Electronics Manufacturing
Published in Jack Arabian, Computer Integrated Electronics Manufacturing and Testing, 2020
As described earlier, the most common, general-purpose dielectric substrate is known as G10 (“G” for glass), which is a woven fiberglass fabric impregnated with epoxy and subsequently cured. G10 came out of a military application because “outgassing” (shedding of molecules of gas previously trapped internally in crevices and pockets) of fire retarding agents in the substrate was not acceptable. If fire retardancy is required, a material known as FR4 is preferred (FR = fire retardant). A harder and stronger, but more brittle, material which has the attribute of higher operating temperature specifications is the material known as FR5 (see Reference 1-03). The additives to the epoxy system which provide the fire retardant characteristics have a tendency to outgas, which further restricts their use in specific design applications, as noted above for G10.
Principles and Technology of SQUIDs
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
If the experiment involves measurements interior to the dewar (cf. Figure 5.10), then a metallic dewar is preferable. Metallic dewars offer significant shielding from environmental noise at frequencies above 10–100 Hz. If the system is to measure magnetic fields exterior to the dewar, the dewar must be magnetically transparent and metallic construction is not appropriate. Dewars for external field measurements (e.g., geophysical or biomagnetic) are normally constructed of nonmetallic, low-susceptibility materials to minimize their magnetic interactions with the SQUID sensors and detection coils. Materials used are typically glass-fiber–epoxy composites such as G-10.
Design of the HL-2M Support System
Published in Fusion Science and Technology, 2023
Deqaun Liu, Tao Lin, Tao Qiao, Lijun Cai, Chengzhi Cao, Yinglong Yuan, Qiang Li
The following solutions to the above issues are considered in the support structure design: Type 304 stainless steel was chosen as the structure material. The control for magnetic permeability is fully fulfilled during the process of welding, heat treatment, cutting, etc.Adjustable structure design and compensation means are considered for the coil position adjustment.Insulated breaks especially in the toroidal closed circuit must be provided. The insulating material G10 is chosen because of its good performance of insulation and strength.The VV is supported by five trunnions located in the equatorial plane to absorb thermal displacement at the baking operation. The VV support is integrated into the PFC support structure.Auxiliary holes or flanges are designed to provide convenient access for welding, assembly, and maintenance, etc.
Experimental Investigation of Thermal Properties of Materials Used to Develop Cryopump
Published in Fusion Science and Technology, 2021
R. Gangradey, J. Mishra, S. Mukherjee, P. Nayak, P. Panchal, J. Agarwal, V. Gupta
Vespel Sp12, which is a high-performance polymer, finds application in the aerospace, semiconductor, and cryogenic fields and is commercially available in various grades. In a cryopump, it finds application as supports and O-ring material. G-10 is a composite material, a kind of fiberglass laminate, which is a type of composite material. This also used as supports in the cryogenic field to avoid heat loads due to solid conduction. Figure 4 shows the thermal properties of G10 and Vespel. The Vespel has a thermal conductivity of 0.58 W/m‧K, and G10 has a thermal conductivity of 0.8 W/m‧K.