chief major main三个词有什么区别

一、词义辨析不一样

1、chief指人时，表同类中职位最高，权力最大；指物时，表同类中最重要，价值最高。

2、major指同其他人或其它物、问题等相比较，显得更加重要和突出。

3、main通常只用于物。指在一定范围内，某物的重要性、体积或力量等超过其它物。

二、词义广泛性不一样

1、chief

英 [tʃiːf]  美 [tʃif]

n. 首领；酋长；族长

adj. 为首的；主要的，首要的

2、major

英 [ˈmeɪdʒə]  美 [ˈmeɪdʒər]

n. 成年人；陆军少校；主修科目；主修…的学生；大调

v. 主修科目，专业

adj. 较大的，较多的；主要的；主修的；大调的

3、main

英 [meɪn]  美 [meɪn]

n. 总管道，总线；干线，电力网，电源；体力

adj. 主要的；全力的，尽力的

三、变形词不一样

1、chief

只有复数： chiefs

2、major

第三人称单数： majors 复数： majors 现在分词： majoring 过去式： majored

3、main

只有复数： mains

main与major的区别主要有以下几点：

一、二者读音不同

1、main

英 [meɪn]   美 [meɪn] 　 　

2、major

英 ['meɪdʒə(r)]    美 ['meɪdʒər] 　 　

二、二者含义不同

1、main

adj. 主要的；最重要的

n. 干线；总管道；[pl](水、煤、电)供应系统；<古>大海

2、major

adj. 较多的；主要的；严重的；(音乐)大调的

n. 成年人；主修（科目）；陆军少校；举足轻重者

v. 主修

三、二者用法上的区别

1、main

通常只用于物。指在一定范围内，某物的重要性、体积或力量等超过其它物。

例证：The speech was most disappointing,it skirted round all the main questions.

这篇演讲非常令人失望,它回避了所有主要的问题。

2、major

指同其他人或其它物、问题等相比较，显得更加重要和突出。

例证：Majors should take more responsibilities and be more intelligent in handling personal relations.

成年人要承担更多的责任,在处理人际关系中也要变得更急灵活。

Power semiconductor devices and power electronics

World's first semiconductor rectifier and the transistor is, when no power semiconductor or microelectronics semiconductor division. In 1958, China began the first research topic Thyristor (originally known as PNPN device). In similar time, the study of integrated circuits began gradually. From semiconductor devices to the two direction. The former became the basis for power electronics, while the latter led to the development and micro-electronics and information electronics.

According to the system, power system devices are classified to the machinery, integrated circuits, electronic systems are included. As the semiconductor leader in the electronic systems, coupled with the semiconductor integrated circuits is the main body, which after a long-term evolution of integrated circuits in a number of occasions, has become almost synonymous with semiconductor devices only.

At the end of the sixties and early seventies, the country has set off a "SCR" hot. The boom continued a long time, great influence, and therefore still believe that the domestic power of semiconductors is the main SCR. The late seventies, the development of a thyristor family. And called the name of a standardized "thyristor." As the technology to regulate the power switch, so the wear and tear on a small device, so as the energy trump card. Its application is to cover all fields. China was first mooted in 1979, the establishment of Power Electronics Society, IEEE slightly earlier than the establishment of the United States Institute of Power Electronics (Power Electronics Society). Power Electronics Society of China was founded, as a result of the importance of professional development is very rapid. However, because the focal point was the relationship, it does not like the United States become an independent professional institutes, and was subsequently set up part of the China Electrotechnical Society.

The translation and definition of Power Electronics for Power Electronics (the original idea was also known as the Power Electronics), and the popularity of power electronics played a role. Mechanical, electrical, electronic and other departments are very concerned about its development. Related to the power semiconductor devices has also been known as the power electronic devices. However, this name is very difficult to find abroad, but the corresponding terms. "Electricity" in reference to electronic access to universal, but also left a number of sequels. People mistakenly believe that only high-power direction is the "power" of the main electronic devices, and the difficulty of the rapid development of the MOSFET as a "power electronics" of the other main. From that point, I would like to use power semiconductor devices as the subject of this article, and power electronic devices can be used to express a broader sense to include other non-semiconductor, including a variety of power electronic devices.

The development of power semiconductor devices in three stages

The development of power semiconductor devices can be divided into three stages. The first stage is 60 to the seventies, when the various types of thyristors and power transistors Darlington significant development, or what might be called the era of bipolar. Its clients are mainly for industrial applications, including power systems, such as locomotive traction. The second stage is 80 to the nineties, due to the rise of the power MOSFET to power electronics into a new area. Modern 4C booming industry: the Communication, Computer, Consumer, Car (communication, computer, consumer electronics, automobiles) to provide a new vitality. Before and after the twenty-first century, the development of power semiconductor devices have entered the third phase, that is, and integrated circuit combined with a growing stage, Figure 1 and Figure II made to the above description of a simple sum. Of course, first of all need to focus on that here is this: when the continuous development of power semiconductor devices, the previous stage has not been the dominant product from the stage of history. For example, SCR is still an important product. China has in recent years the introduction of ultra-high-power thyristor, thyristor-controlled technology, such as China's major power transmission project, providing a key device. Recently, in considering the introduction of IGCT technology. In this regard it should be said that has gradually moved towards the world. This is our country going on the many major infrastructure. Although the view from the United States, the production of high-power thyristors have been less and less on the economic development of the two countries are not identical. I draw in Figure 2 in power semiconductor devices in both directions in the development. The left side of the bipolar nature of the direction toward the integration of ultra-high-power and direction. The right direction is unipolar, it is more established and integrated circuits of the inseparable relationship between closely.

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