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Toxic effects vary depending on the specific PCB. In terms of their structure and toxicity, PCBs fall into two distinct categories, referred to as coplanar or non-ortho-substituted arene substitution patterns and noncoplanar or ortho-substituted congeners. Structures of the twelve dioxin-like PCBs Coplanar or non-ortho
Congener descriptors give a shorthand notation for geometry and substituent positions. The twelve congeners that display all four of the descriptors are referred to as being "dioxin-like", referring both to their toxicity and structural features which make them similar to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2378-TCDD). [1]
Example of component sizes, metric and imperial codes and comparison included Composite image of a 11×44 LED matrix lapel name tag display using 1608/0603-type SMD LEDs. Top: A little over half of the 21×86 mm display. Center: Close-up of LEDs in ambient light. Bottom: LEDs in their own red light.
Multi-chip modules come in a variety of forms depending on the complexity and development philosophies of their designers. These can range from using pre-packaged ICs on a small printed circuit board (PCB) meant to mimic the package footprint of an existing chip package to fully custom chip packages integrating many chip dies on a high density interconnection (HDI) substrate.
A via (Latin, 'path' or 'way') is an electrical connection between two or more metal layers of a printed circuit boards (PCB) or integrated circuit. Essentially a via is a small drilled hole that goes through two or more adjacent layers; the hole is plated with metal (often copper) that forms an electrical connection through the insulating layers.
Via fences are used to shield microstrip and stripline transmission lines, guard edges of printed circuit boards, shield functional circuit units from each other, and to form the walls of waveguides integrated into a planar format. Via fences are cheap and easy to implement, but use up board space and are not as effective as solid metal walls.
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Fig.1: Wineglass model for IMRaD structure. The above scheme shows how to line up the information in IMRaD writing. It has two characteristics: the first is its top-bottom symmetric shape; the second is its change of width, meaning the top is wide, and it narrows towards the middle, and then widens again as it goes down toward the bottom.