ISBT128码是血液采集、加工和输血方面全世界唯一通用的标识系统。

以下关于ISBT128码正确的描述是

A:在ISBT128条码为基础上，按医学标准增加了国际输血规定 B:适用于国际上许多国家在安全方面的输血要求 C:数据结构和条码符号与各种现行条码标准的一致性 D:这个标准将取代目前世界上已采用的许多血液条码国家标准，不允许与大多数国家标准同时存在 E:Codabar码数据流转变为ISBT128码数据流时不必用符号标识符

ISBT128码是血液采集、加工和输血方面全世界唯一通用的标识系统。

以下属于ISBT128码的特征是

A:可选择128个不同的字符来编码 B:有一个极高致密的混合编码字符集用于为长数据编码 C:每一个条码特征都有3个分开的自我校验机制 D:不允许ABCCodabar和ISBT128标签系统共存 E:对世界上任何一个采供血机构都分配有一个唯一的标识码，使用期限为100年

ISBT128码是血液采集、加工和输血方面全世界唯一通用的标识系统。

以下关于ISBT 128码错误的描述是

A:在ISBT 128条码为基础上，按医学标准增加了国际输血规定 B:适用于国际上许多国家在安全方面的输血要求 C:数据结构和条码符号与各种现行条码标准的一致性 D:这个标准将取代目前世界上已采用的许多血液条码国家标准，不允许与大多数国家标准同时存在 E:Coda bar码数据流转变为ISBT 128码数据流时不必用符号标识符

ISBT128码是血液采集、加工和输血方面全世界唯一通用的标识系统。

以下哪项不属于ISBT 128码的特征

A:可选择128个不同的字符来编码 B:有一个极高致密的混合编码字符集用于为长数据编码 C:每一个条码特征都有3个分开的自我校验机制 D:不允许ABC Coda bar和ISBT 128标签系统共存 E:对世界上任何一个采供血机构都分配有一个唯一的标识码，使用期限为100年

CDMA系统中的地址码和扩频码都包含（）

A:Walsh码 B:m序列码 C:Gold码

CDMA系统用到的三种码是（）。

A:PN短码 B:walsh码 C:PN长码 D:gold码

WCDMA系统中的扰码取自（）。

A:M序列 B:TURBO码 C:WALSH矩阵 D:GOLD序列

It is only a shiny, yellow metal, but it is one of the most valuable metals on earth. Since the beginning of time, men have looked for this extremely valuable item, gold.
Gold is soft and easy to form into different objects. If it gets wet, it does not rust like iron or other metals. Acids do not change it. One important reason that gold is so valuable is that it is scarce.
Due to its softness, gold must be combined with other metals to harden it and give it strength. By hardening gold, people can then make coins and jewelry with it. Metals commonly mixed with gold are nickel, platinum, and copper. Gold jewelry bears a number and the letter K. The K means karat(carat), which is a measure of the amount of pure gold in the jewelry. Pure gold is 24K. Therefore, a necklace which is 14K is fourteen parts gold and ten parts other metal.
Many countries utilize gold for certain coins, but this practice is not as common now as it once was. The United States, for instance, stopped making gold coins in 1933.

A:A Valuable Metal—Gold B:Looking for Gold C:Jewelry and Coins D:What is Karat

Gold used in jewelry is mixed with harder metals to add strength and durability. The metals added can also be used to change gold’s color, giving it a fashionable rose or white tint, or to lighten or darken the natural yellow tone of pure gold. Mixtures like these, of less costly metals with more valuable ones, are called alloys. Copper and silver are the most common metals mixed with gold to make yellow gold jewelry. White gold is usually made with an alloy of gold and nickel.
The measure of gold’s purity is called a karat. The higher the karat rating, the higher the amount of pure gold: 24 karat is pure gold, 18 karat is 75% pure gold, 14 karat is 58.5% pure gold, and 9 karat is 37.5% pure gold. All other things being equal, the higher the percentage of pure gold used in the alloy, the more valuable and expensive the jewelry will be.
Gold jewelry pieces are usually stamped with a marking to identify the karat amount. While gold that is 24K is too soft for jewelry, 18K, 14K and 9K gold are all appropriate for jewelry, and they all make pieces that look great and wear beautifully.

A:Although gold is very valuable, it is also very expensive. B:Gold jewelry is stamped with its karat weight. C:Gold jewelry is made using alloys. D:Colored gold is more valuable than white gold.

Why does the author mention the California gold rush?

A:To explain the need for an increased supply of gold B:To indicate the extent of United States mineral wealth C:To describe the mood when oil was first discovered D:To argue that gold was more valuable than oil