取"蓝牙"一词的意义是什么?"蓝牙"一词取自一位在公元10世纪统一了丹麦的国王,哈拉德二世（Harald）的绰号,有和含

Bluetooth technology's future
nowadays bluetooth technology is not strange to us,in our telephones and computers
it can be seen anywhere.
(nowadays bluetooth has gained more popurlarity as it can be seen everywhere such as in our telephones and computers这样感觉更连贯通顺)
A bluetooth connection is wireless and automatic,and it only connection（connect这需要动词） the
Next level by removing（这是什么意思?表达不清）.So what the future of Bluetooth technology?
（个人认为这里说未来怎么样不恰当,应该直接说他有怎么样的发展空间,比如说有三项值得改进的地方,比如说语音控制,更方便人们使用.Firstly,It brings people convenience as it's able to be easily controled by human voice.然后来举个例子old people and the disables could take good care of themselves,speaking to the machine.）
I think it would have three alter .Firstly,as the technology develop ,it would be remote control,
.secondly,it has cover our daily lives more aspect,not only on the telephones and computuers
,maybe it can be connect the television or radio.Thirdly,i think the bluetooth technology
Is common to everyone so that not only the children but also the older can use it.
The bluetooth technology have a very great develop space,if only we can enhance
The rate of technology,i believe it have a bright future is waiting us.
（第二第三点在说明观点 举例说明.这样文章更有条理 更清晰 更有说服力）
（你有连词的使用 倾向去使用复杂句,这都很好很有语言的感觉,然而还不够熟练,当然还需要你更多的努力,

Make a discussion on present blue tooth technology's present situation and the development and carry on the analysis to the blue tooth agreement system's baseband data transmission mechanism,narrated the blue tooth wireless link to seal the frequency,the baseband agreement,the reliable measure which the chain management agreement (LMP) used,as well as blue tooth technology,in the intelligence lived in system's application.

解题思路：（1）凸透镜成像的三种情况：
①U＞2f时，凸透镜成倒立缩小的实像，2f＞V＞f，应用于照相机和摄像头．
②2f＞U＞f时，凸透镜成倒立放大的实像，V＞2f，应用于投影仪和幻灯机．
③U＜f时，凸透镜成正立放大的虚像，应用于放大镜．
（2）凸透镜成实像时，物距减小，像距增大，像增大．
（3）“蓝牙”是一种短距离的无线通信技术，故是利用电磁波来传递信息的．

摄像头的镜头相当于凸透镜，U＞2f时，凸透镜成倒立缩小的实像；分析图甲和乙，汽车的像越来越大，即物距越来越小，所以汽车靠近摄像头．
“蓝牙”是一种短距离的无线通信技术，故是利用电磁波来传递信息的．
故答案为：凸透；近；大于二倍焦距；电磁波．

点评：
本题考点： 凸透镜成像的应用；红外线．

考点点评： （1）掌握凸透镜成实像时，物距减小，像距增大，像增大．
（2）利用三种成像情况解决生活中的问题
（3）知道手机蓝牙是利用电磁波 来传递信息的

一般蓝牙耳机支持语音,数传和立体声的功能,你的手机只有那3个选项的话,就可能不支持数传了.那语音包含蓝牙头戴式应用（Headset profile）,蓝牙免提应用（Hands-free profile）,也就是你说的BT headset 和BT hand-free .
BT stereo headset 是A2DP Profile,功能也就是用蓝牙听MP3,和普通耳机比,少了连接的线而已.
所以你要根据不同的作用,选择不同的选项.

对于蓝牙的CLASS这里也随便提一下,有些朋友以为CLASS是蓝牙有效连接距离的意思,其实这样的看法是不对的.其实按照蓝牙规范的规定,CLASS并不用来规定距离的,而是标明输出功率.通常Class 1为1mW (0dBm)～100mW (20dBm)；Class 2:是0.25mW (-6dBm)～2.5mW (4dBm),正常情况下1mW(0dBm).只要发射功率能超过0dBm就是属于Class 2的范围,但是如果超过4dBm的话 那就是Class 1；而BHX70支持的Class 3则为≤ 1mW (0dBm).而通常情况下Class 1可达100米左右 Class 3可达10米的连接.

This paper introduces a kind of TI MSP430F2132as the control core of intelligent anti-theft system.Is mainly composed of a control module,GSM module,a Bluetooth module and a power supply part.When in use,the system into valuables and the Bluetooth mobile phone Bluetooth pairing with the user,once the system leaving the user with a certain distance the user mobile phone will receive system messages or to fight the phone to achieve the anti-theft effect.This system has wide application,portable,low power consumption,strong practicability,security and good benefits.

1.霜落熊升树,林空鹿饮溪2.僵卧孤村不自哀,尚思为国戍轮台3.山下兰芽短浸溪,松间沙路净无泥.萧萧暮雨子规啼.

Wi-Fi是一种可以将个人电脑、手持设备（如PDA、手机）等终端以无线方式互相连接的技术.Wi-Fi是一个无线网路通信技术的品牌,由Wi-Fi联盟(Wi-Fi Alliance)所持有.目的是改善基于IEEE 802.11标准的无线网路产品之间的互通性.现时一般人会把Wi-Fi及IEEE 802.11混为一谈.甚至把Wi-Fi等同于无线网际网路.
C无线局域网
短距离通信的无线电技术.

The so-called Bluetooth (Bluetooth) technology,is actually a short-range radio technology,the use of "Bluetooth" technology,which can effectively simplify the palm-sized PCs,notebook computers and mobile phones and other mobile phones for communication between terminal equipment can also be successfully These simplify the equipment and Internet communications between the Internet,so that these modern communication equipment and data transmission between the Internet more quickly and efficiently,in order to expand the wireless communications path.Bluetooth to adopt decentralized network structure,as well as fast frequency hopping and short-packet technology to support point-to-point and point-to-multipoint communication,common in the global 2.4GHz ISM (ie industry,scientific,medical) band.The data rate of 1Mbps.Using time division duplex transmission scheme to achieve full-duplex transmission.
蓝牙的英文名称是bluetooth,是1998年5月由爱立信、IBM、英特尔、诺基亚和东芝等5家公司联合制定的短距离无线通信技术标准,其目的是实现最高数据传输速率1Mb/s(有效传输速率是721kb/s)、最大传输距离为10m的无线通信.Bluetooth原为欧洲中世纪的丹麦国王Harald Ⅱ的名字,他为统一四分五裂的瑞典、芬兰和丹麦立下了不朽的功劳,以此命名即将成为全球通用的无线技术,也许另有含义.
最早提出蓝牙概念的是瑞典的爱立信移动通信公司.它是在一次为移动电话及电话附件之间寻找一种低功耗、低成本的无线接口时萌发出这样一种创意的.作为无线接口,有如下要求：
•对其工作的频率范围、技术造价、容量和接口尺寸大小的预先规定,目的是保证该技术具有所有线缆连接所没有的优势.
•无线单元的尺寸和功耗必须足够小,目的是可安装进许多便携设备中.
•支持语音和数据通信
•具有全球通用性
Bluetooth is the English name of bluetooth,it is in May 1998 by Ericsson,IBM,Intel,Nokia and Toshiba jointly developed by five companies short-range wireless communication technology standards,the aim is to achieve the highest data transfer rate of 1Mb / s (effective transfer rate is 721kb / s),the maximum transmission distance of 10m of wireless communications.Bluetooth was the king of Denmark,the Middle Ages in Europe the name of Harald Ⅱ,his uniform torn Sweden,Finland and Denmark have made a monumental contribution,as will soon become a global name of the wireless technology,may have meaning.
The concept of the first Bluetooth is a Swedish company Ericsson Mobile Communications.It is the first time for mobile phones and telephone between the Annex to find a low-power,low-cost wireless interface when the germination of such a creative.As a wireless interface,the following requirements:
• the frequency range of its work,technology cost,capacity and interface of a predetermined size,the purpose is to ensure that the technology to connect all the cables do not have advantages.
• wireless cell size and power consumption must be small enough,the purpose is to be installed into many portable devices.
• Support for voice and data communications
• a global common
-------
希望可以符合您的要求哦----

Thanks to the help of Bluetooth,more and more people believe that it is no longer a problem to answer the phone when driving,because the Bluetooth liberates people from constraints of answering phones with their hands.
山风精灵技高一筹

摄像头的镜头相当于凸透镜，U＞2f时，凸透镜成倒立缩小的实像；分析图甲和乙，汽车的像越来越大，即物距越来越小，所以汽车靠近摄像头．
“蓝牙”是一种短距离的无线通信技术，故是利用电磁波来传递信息的．
故答案为：凸透；近；大于二倍焦距；电磁波．

摄像头的镜头相当于凸透镜，U＞2f时，凸透镜成倒立缩小的实像；分析图甲和乙，汽车的像越来越大，即物距越来越小，所以汽车靠近摄像头．
故答案为：凸透；近；大于二倍焦距．

从物理学角度上看,电磁波从波长最短开始,顺序如下：γ射线、紫外线、可见光、红外线、无线电波（无线电波又分为：微波、短波、中波、长波）.
而电磁波的本质不过是不断变化的电场和磁场.
而楼主所列举的各种名称中,应当都属于电磁波.只是对最近几年在计算机网络中所使用的技术标准,本人不是很擅长,所以不知道蓝牙、wi-fi、802.11n等的波长（或频率）,所以不知道这些电磁波所属的分类.
而其中射频是电磁波的另一种称呼,发射线,这个本人不清楚.

Infrared connection,attachment function,service,address book,alarmclock,treasure chest,shortcut,blue tooth function,electron.

dragnet investigation
你怎么谢我呢?

解题思路：（1）凸透镜成像的三种情况：
①U＞2f时，凸透镜成倒立缩小的实像，2f＞V＞f，应用于照相机和摄像头．
②2f＞U＞f时，凸透镜成倒立放大的实像，V＞2f，应用于投影仪和幻灯机．
③U＜f时，凸透镜成正立放大的虚像，应用于放大镜．
（2）凸透镜成实像时，物距减小，像距增大，像增大．
（3）“蓝牙”是一种短距离的无线通信技术，故是利用电磁波来传递信息的．

摄像头的镜头相当于凸透镜，U＞2f时，凸透镜成倒立缩小的实像；分析图甲和乙，汽车的像越来越大，即物距越来越小，所以汽车靠近摄像头．
“蓝牙”是一种短距离的无线通信技术，故是利用电磁波来传递信息的．
故答案为：凸透镜；近；电磁波．

点评：
本题考点： 凸透镜成像的应用；电磁波的传播．

考点点评： （1）掌握凸透镜成实像时，物距减小，像距增大，像增大．
（2）利用三种成像情况解决生活中的问题．
（3）知道手机蓝牙是利用电磁波来传递信息的．

解题思路：（1）电池工作时，将化学能转化为电能；
（2）根据铭牌可知音响的正常工作电压为3V；
（3）根据W=Pt求出正常工作时的消耗的电能；
（4）使用“蓝牙”是靠电磁波传递信息．

A、锂电池工作时，将化学能转化为电能，故A错误；
B、由铭牌可知音响的额定电压为3V，故B错误；
C、音响正常工作时每秒消耗电能W=Pt=3W×1s=3J，故C正确；
D、音响使用“蓝牙”是靠电磁波传递信息．
故选：C．

点评：
本题考点： 电功的计算；电磁波的传播．

考点点评： 此题考查学生关于用电器铭牌信息的理解和掌握．