电磁辐射,又称电磁波,是由同相振荡且互相垂直的电场与磁场在空间中以波的形式传递能量和动量,其传播方向垂直于电场与磁场构成的平面. 电磁辐射的载体为光子,不需要依靠介质传播,在真空中的传播速度为光速.电磁辐射可按照频率分类,从低频率到高频率,主要包括无线电波.微波.红外线.可见光.紫外线.X射线和伽马射线. 人眼可接收到的电磁辐射,波长大约在380至780nm之间,称为可见光.只要是本身温度大于绝对零度的物体,除了暗物质以外,都可以发射电磁辐射,而世界上并不存在温度等于或低于绝对零度的物体,因此,…

Radio Basics for RFID The following is excerpted from Chapter 3: Radio Basics for UHF RFID from the Book, The RF in RFID: Passive UHF RFID in Practice by Daniel M. Dobkin. Order a copy of The RF in RFID: Passive UHF RFID in Practice before December 3…

目录 一. 前言 1.1 本文动机 1.2 PBR知识体系 1.3 本文内容及特点 二. 初阶:PBR基本认知和应用 2.1 PBR的基本介绍 2.1.1 PBR概念 2.1.2 与物理渲染的差别 2.1.3 PBR的特征 2.2 PBR的衍变历史 2.2.1 Lambert(1760年) 2.2.2 Smith(1967年) 2.2.3 Phong(1973年) 2.2.4 Cook-Torrance(1982年) 2.2.5 Oren Nayarh(1994年) 2.2.6 Schlick(…

背景 信息物理系统CPS通过集成先进的感知.计算.通 信.控制等信息技术和自动控制技术,构建了物理空间与信息空间中人. 机.物.环境.信息等要素相互映射.适时交互.高效协同的复杂系统, 实现系统内资源配置和运行的按需响应.快速迭代.动态优化.我们把信息物理系统定位为支撑两化深度融合的一套综合技术体系,这套综合技术体系包含硬件.软件.网络.工业云等一系列信息通信和自动控制技术, 这些技术的有机组合与应用,构建起一个能够将物实体和环境精准映射到信息空间并进行实时反馈的智能系统,作用于生产制造全过程.…

链接. General Books on Electromagnetics When our department recently reviewed our junior-level text, we were struck by the large number of books now available from wh ich to teach introductory electromagnetics. Here, I mention only my two personal favo…

Alpha particles consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus. They are generally produced in the process of alpha decay, but may also be produced in other ways. Alpha particles are named after…

A technique is provided for generating stubs. A processing circuit receives a call to a called function. The processing circuit retrieves a called function property of the called function. The processing circuit generates a stub for the called functi…

http://en.wikipedia.org/wiki/J1708 J1708 SAE J1708 is a standard used for serial communications between ECUs on a heavy duty vehicle and also between a computer and the vehicle. With respect to Open System Interconnection model (OSI), J1708 defines t…

Obtaining an intuitive idea for why antennas radiate is helpful in understanding the fundamentals of antennas. On this page, I'll attempt to give a low-key explanation with no regard to mathematics on how and why antennas radiate electromagnetic fiel…

一.有线传输介质(Guided Transmission Media)  1.1 双绞线(Twisted Pair) 双绞线(twisted pair)是一种综合布线工程中最常用的有线传输介质(导向传输介质),是由两根具有绝缘保护层的铜导线组成的. 绞的作用:把两根绝缘的铜导线按一定密度互相绞在一起,每一根导线在传输中辐射出来的电波会被另一根线上发出的电波抵消,有效降低信号干扰的程度.双绞线在局域网有着广泛应用. 根据有无屏蔽层,双绞线分为屏蔽双绞线(Shielded Twisted Pair,…