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    Do you often use a cell phone? Do you take the subway(地铁)to school every day? These items(项目) make our modern life easier. But do you know how we should behave properly while using them? The following suggestions might be helpful.

    For cell phone users

    ◆Keep your voice down when you make a phone call in public. Shouting on the phone may make others feel uncomfortable. And you'd better not use it during an appointment(约会).

    ◆Stop sending messages or playing games with your cellphone at a dinner or a party. It's a good time to communicate with your family and friends.

    ◆Don't make or answer a call while driving. It is very dangerous for both you and your passengers.

   


For subway passengers

    ◆You are supposed to wait in line while buying tickets and getting on the subway.

    ◆You're not allowed to eat, drink or smoke on the subway train. The smell and noise may trouble others. It's our duty to keep the train clean and tidy. Besides, smoking is bad for health.

    ◆ You can't take pets on the train. As we all know, animals may spread diseases (疾病),  get the train dirty and make much noise.

    ◆ You'd better not lie across the subway seats even if the train isn't crowded. Offering your seat to someone who needs it is regarded as good manners.


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同类题5

阅读《超声波指纹识别技术》,回答问题.

超声波指纹识别技术

自从iPhone5s带着指纹识别Touch ID火了以后,这门技术已经成为iOS和Android旗舰手机上的标配了.虽然虹膜识别等生物识别技术也偶尔向Touch ID发起挑战,但仍无法撼动其地位.不过,这种情况可能要改变了,因为手机芯片厂商高通来了一发黑科技﹣﹣超声波指纹识别技术(亦称超声波Sense ID).

原有的指纹识别的原理是电容式信号感测,核心是电信号.手指(人体)的微电场与电容传感器之间形成微电流,指纹嵴与峪(波峰与波谷)间会有高低电容差,这也是描绘指纹图象的基础.

超声波指纹识别如其名,是利用的是超声波去做检测.利用超声波具有穿透材料的能力,且随材料的不同产生大小不同的回波(超声波到达不同材质表面时,被吸收、穿透与反射的程度不同).因此,利用皮肤与空气对于声波阻抗的差异,就可以区分指纹嵴与峪所在的位置.超声波技术所使用的超声波的能量被控制在对人体无损的程度.

超声波指纹识别的优势在于可以识别指纹的3D纹路,采集更精细的指纹数据,而电容式的识别是2D图象.另外一点优势是可以置于塑料、玻璃等多种材料之下,不对机身外观造成影响,不受汗水、油污的影响.

请根据上述材料和你学过的物理知识,回答下列问题: