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【单选题】
Universal Product Code What are the zebra stripes (See the figure) on the Instant Mashed Patato Flakes package? They are special black and white vertical lines. These black and white stripes can be read by an optical scanner, or computer. The 'scanner', which reads the lines of code, is a small laser beam of light. When the light rays is broken by the black stripes, the computer 'reads' the information about the product. This code is called the Universal Product Code (UPC). It is designed to add speed and efficiency to stores by using computers. It can do this in several ways. First, it is not necessary for workers to put individual prices on items. By using UPC, the computer can print out the accurate price of the item. Errors in prices are eliminated, or done away with. Also, the time spent checking out is reduced UPC gives an itemized receipt to the customer with all the items, prices, and totals. The store clerk does not need to spend time checking the price on the item and punching it into the cash register. This UPC computerized system will probably save as much as 45 percent of the checkout clerk's time. What do the stripes mean? How does the computer interpret the stripes? The number printed below the vertical bars identifies the manufacturer and the manufacturer's item. As many as 10 trillion individual machine-readable numbers can be used with this system. In the example, the 0 on the left side means that it is a grocery item. The numbers 36800 indicate the manufacturer, in this case it is the Food Club Company. The last five digits, 51512, mean it is a pack of mashed patato flakes. The light rays from the light beam read these lines, and the message is sent directly to the computer. The computer then finds the information about this product (price, inventory data) and sends it instantly back to the terminal at the checkout counter. At the same time, it keeps an inventory for the store manager. Many products have labels with these stripes. The figures printed below the stripes are codes of the producer and the product.
A.
right
B.
wrong
C.
Doesn't say
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【单选题】(2000)昼夜体温波动的特点是
A.
昼夜间体温呈周期性波动
B.
午后4~6时体温最低
C.
上午8~10时体温最高
D.
昼夜间波动的幅度超过1℃
E.
体温波动与生物钟无关
【单选题】昼夜体温波动的特点是
A.
体温波动与生物钟无关
B.
午后4~6时体温最低
C.
上午8~10时体温最高
D.
昼夜间体温呈周期性波动
E.
昼夜间波动的幅度超过1°C
【单选题】利用外界因素对于光纤中光波相位的变化来探测各种物理量的传感器,称为( )。
A.
相位调制型传感器
B.
相位结合型传感器
C.
相位振动型传感器
D.
相位干涉型传感器
【单选题】昼夜体温波动的特点是
A.
昼夜间体温呈周期性波动;
B.
午后4-6时体温最低;
C.
上午8-10时体温最高;
D.
昼夜间波动幅度超过1℃;
E.
体温波动与生物钟无关;
【单选题】摄像机清晰度(分辨率)选型要点为______。
A.
如果监视目标照度不高,而对监视图像清晰度要求较高时,宜选用黑白摄像机;对有景物色彩及细部要求的监视场合,宜选用彩色摄像机
B.
表示摄像机分辨图像细节的能力,通常用电视线(TVL)来表示。视频监控系统使用的摄像机,水平清晰度要求彩色摄像机在270TVL以上,黑自摄像机在400TVL以上
C.
在镜头光圈大小一定的情况下,摄像机获取规定信号电平所需要的最低靶面照度,就称作该摄像机的灵敏度。如果被摄物体照度再低,监视器屏幕上将是一幅很难分辨层次的灰暗图像。一般所选摄像机的灵敏度为被摄物体表面照度的1/10
D.
摄像机的图像信号与噪声电压的比值。往往用S/N表示。摄像机信噪比的典型值在45~55dB之间。信噪比越高越好,视频监控系统中使用的摄像机,一般要求其信噪比高于40dB
【单选题】昼夜体温波动的特点是
A.
昼夜间体温呈周期性波动
B.
午后4、6时体温最低
C.
上午8、10时体温最高
D.
昼夜间波动的幅度超过1℃
E.
体温波动与生物钟无关
【单选题】在电极式锅炉水位控制系统中,在——情况下,给水泵电机保持断电,停止向锅炉供水。
A.
高水位电极水垢太多
B.
低水位电极水垢太多
C.
高水位电极漏电
D.
低水位电极漏电
【单选题】利用外界因素对于光纤中光波相位的变化来探测各种物理量的传感器,称为( )。
A.
相位干涉型传感器
B.
相位调制型传感器
C.
相位结合型传感器
D.
相位振动型传感器
【单选题】( )是商业银行最基本也是最能反应其经营活动特征的职能。
A.
支付中介职能
B.
信用创造职能
C.
信用中介职能
D.
金融服务职能
【单选题】昼夜体温波动的特点是
A.
昼夜间体温呈周期性波动
B.
午后4-6时体温最低
C.
上午8-10时体温最高
D.
昼夜间波动幅度超过1℃
E.
体温波动与生物钟无关
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