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电子元器件与实用电路基础(1)
本视频介绍了有关初级工的基础知识。基础知识主要包括电子元器件的种类、特点及基本功能,基本单元电路的信号知识与基础电路分析等内容。初学者看了就可以跟着学、跟着做,是理想的自学教材。
  1. 2009/11/11
  2. 人气(26169)
  3. 星级(10)
  4. 评论(5)
电子元器件与实用电路基础(2)
本视频介绍了有关初级工的基础知识。基础知识主要包括电子元器件的种类、特点及基本功能,基本单元电路的信号知识与基础电路分析等内容。初学者看了就可以跟着学、跟着做,是理想的自学教材。
  1. 2009/11/11
  2. 人气(19139)
  3. 星级(10)
  4. 评论(2)
气动手臂AirArm
通过分析龙虾和蝗虫的腿以及人类手指的形态得到了气动手臂的灵感。它是一个带有外部骨架的两节式桥臂,由气动肌腱驱动。智能控制技术使气动手臂能赶上水滴的速度。 气动手臂在技术上的意图是能够在指定半球状运行范围内延伸到尽可能多的区域。 选择一般技术实践的常规原理,使带气动肌腱的两节式伸缩系统同时反向运行。 AirArm is biologically inspired by analyses of lobsters’ and grasshoppers’ legs and by human pointing gestures. It is a two-segmented arm with an external skeleton powered by pneumatic muscles. Intelligent control technology enables AirArm to catch drops of water. The technical purpose of AirArm is to reach as many points as possible within a hemispherical operating range defined from a specified point in space. A two-segmented flexing system with muscles operating together in contrary motion was chosen as the general principle for technical realisation.
  1. 2009/11/9
  2. 人气(7267)
  3. 星级(10)
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空中水母AirJelly
空中水母的环境是空气。与水下水母不同,远程控制的水母——空中水母不是在水中游,而是在广阔的空中滑翔,因为它有一个中央电机装置和一个智能听候指令的体系。它能够这样是因为它有一个充满氦气的球形网。 空中水母仅有的动力来源就是连接中央电动驱动器的两个锂离子电池。中央驱动器把动力传输到一个锥齿轮上,然后再传给八个连续的直齿轮,直齿轮通过曲柄带动水母上的八个“触角”。每个“触角”都设计成鱼鳍鳍条结构。把蠕动当做这个球形网的动力到目前为止在空军史上还是空白。空中水母是第一个以蠕动为驱动力的室内飞行物体。这种新型的驱动理念基于反弹原理的助推力,让水母轻轻地在空中穿行。 AirJellys environment is the air. Unlike AquaJelly, the remote-controlled jellyfish AirJelly does not swim through water, but instead glides instead through a sea of air thanks to its central electric drive unit and an intelligent, adaptive mechanism. It is able to do so because it consists of a helium-filled ballonett. AirJellys sole source of power is two lithium-ion polymer batteries connected to the central electric drive unit. It transmits the force to a bevel gear and from there to a succession of eight spur gears, which move the eight tentacles of the jellyfish via cranks. Each tentacle is designed as a structure with Fin Ray Effect . Propulsion of a ballonett by means of peristaltic motion is hitherto unknown in the history of aviation. AirJelly is the first indoor flight object with peristaltic drive. This new drive concept, with propulsion based on the principle of recoil, moves the jellyfish gently through the air.
  1. 2009/11/6
  2. 人气(6327)
  3. 星级(10)
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立体鼹鼠机—吸引人的可编程机器人系统
立体鼹鼠机在不久的将来会在技术培训中发挥重要的作用。这些备有电脑芯片的立方体可以紧密接连接在一起。鼹鼠机之间可以相互沟通交流。能量和信号从一个立体鼹鼠机传递给下一个,这样也保证了能量的供应以及信号的传递。年轻人可以用这种机器给自己制造的机器人编程。Molecubes – an attractive programmable robotics system Molecubes could play a significant role in technical training in the near future. These cubes, fitted with computer chips, can be successively attached to each other. Each Molecube communicates with all the other cubes; the energy supply and transmission of signals from one Molecube to the next are thereby ensured. Young people can use the Molecubes to build and program their own robots.
  1. 2009/10/31
  2. 人气(6262)
  3. 星级(10)
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带有鳍形夹具的仿生三角架—多方位运动和自动抓取
仿生三角架利用了自然界中鱼鳍的结构,首次将三维空间应用到空中企鹅和水下企鹅项目中,以便实现高效和多方位的自动化。三个可扩展伸缩的金丝玻璃纤维杆降低了需要被替换的量,同时允许最大90度的运动。BionicTripod with FinGripper versatile movement and adaptive grasping The BionicTripod makes use of the bionic Fin Ray® structure, which was transferred to three-dimensional space for the first time in the AirPenguin and AquaPenguin projects for efficient, versatile automation. Three extendible and retractable filigree fibreglass rods reduce the mass to be displaced, while allowing a maximum scope of movement of up to 90 degrees.
  1. 2009/10/29
  2. 人气(5747)
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[第17讲]NAND flash 读写
NAND FLASH存储器件有非易失、容量大、功耗低、易擦除等特点,这里就涉及到FLASH的种类问题,NORFLASH和NANDFLASH区别在于:NOR的特点是芯片内执行,即应用程序可以直接在flash闪存内运行,不必再把代码读到系统RAM中。但是工艺复杂,价格比较贵。NAND结构能提供极高的单元密度,可以达到高存储密度,大存储容量,而且便宜。缺点,就是无法寻址直接运行程序,只能存储数据。另外NAND FLASH 非常容易出现坏区,所以需要有校验的算法。在NAND闪存中每个块的最大擦写次数是一百万次,而NOR的擦写次数是十万次。NAND存储器除了具有10比1的块擦除周期优势,典型的NAND块尺寸要比NOR器件小8倍。
  1. 2009/10/28
  2. 人气(3989)
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连续ARQ协议-计算机网络基础(9-10)
连续ARQ协议.自动重传请求(Automatic Repeat-reQuest,ARQ)是OSI模型中数据链路层的错误纠正协议之一。它包括停止等待ARQ协议和连续ARQ协议,錯誤偵測(Error Detection)、正面確認(Positive Acknowledgment)、逾時重傳(Retransmission after Timeout)與負面確認繼以重傳(Negative Acknowledgment and Retransmission)等機制。
  1. 2009/10/27
  2. 人气(6285)
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空中企鹅AirPenguin_Festo仿生技术
airPenguin –空中企鹅——自动飞翔的机器企鹅. 随着空中企鹅的问世, Festo公司的工程师们创造了人造企鹅,并教会他们“在空中自主飞行”。为此,控制和调节技术进一步发展成自我调节生物机电一体化系统,该系统可以在今后的生产适应性发挥作用。 一组3只自动飞行的企鹅自由盘旋在空中超声发射站监控下的固定区域。企鹅能够自由的在这个空间内移动,因为一个微控制器赋予了他们自由的意志来以开拓这片空间。 autonomously flying robotic penguins With the AirPenguins, the engineers from Festo have created artificial penguins and have taught them "autonomous flight in the sea of air". For this purpose, control and regulating technology had to be further developed into self-regulating biomechatronic systems, which could also play a future role in adaptive production. A group of three autonomously flying penguins hovers freely through a defined air space that is monitored by ultrasound transmission stations. The penguins are at liberty to move within this space; a microcontroller gives them free will in order to explore it.
  1. 2009/10/23
  2. 人气(5729)
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计算机网络体系结构-计算机网络基础(3-4)
OSI参考模型,OSI (Open System Interconnection) 参考模型 1983年ISO 的 OSI 模型正式成为国际标准。 Fig. 1-16, Fig. 1-17 1. 物理层(The Physical Layer) 在物理线路上传输原始的二进制数据位(基本网络硬件)。 2. 数据链路层(The Data Link Layer) 在有差错的物理线路上提供无差错的数据传输(Frame)。 3. 网络层(The Network Layer) 控制通信子网提供源点到目的点的数据传送(Packet)。 4. 运输层(The Transport Layer) 为用户提供端到端的数据传送服务。 5. 会话层(The Session Layer) 为用户提供会话控制服务(安全认证)。token management and synchronization (insert checkpoints into the data stream) 6. 表示层(The Presentation Layer) 为用户提供数据转换和表示服务。 7. 应用层(The Application Layer)
  1. 2009/10/23
  2. 人气(5012)
  3. 星级(10)
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总数:258 | 当前第24/26 首页 上一页 ... 17 18 19 20 21 22 23 24 25 26 下一页 尾页