自发发射

The phenomenon was first reported in 1896 by Henri Becquerel for a uranium salt, and it was soon found that all uranium compounds are radioactive due to the uranium's radioactivity.

放射性：某些类的物质自发发射辐射的特性。1896年贝克勒耳第一个报告在铀盐中发现了这一现象，不久发现由于铀有放射性，所以所有的铀化合物都是放射性的。

"Radioactivity: Property exhibited by certain types of matter of emit ting radiation spontaneously. The phenomenon was first reported in 1896 by Henri Becquerel for a uranium salt, and it was soon found that all uranium compounds are radioactive due to the uranium's radioactivity."

放射性：某些类的物质自发发射辐射的特性。1896年贝克勒耳第一个报告在铀盐中发现了这一现象，不久发现由于铀有放射性，所以所有的铀化合物都是放射性的。

Any of three processes of radioactive disintegration in which a beta particle is spontaneously emitted by an unstable atomic nucleus in order to dissipate excess energy.

某些不稳定原子核为耗散其过剩能量而自发发射一个β粒子的三种放射性衰变过程的统称。

Any of three processes of radioactive disintegration in which a beta particle is spontaneously emit ted by an unstable atomic nucleus in order to dissipate excess energy.

某些不稳定原子核为耗散其过剩能量而自发发射一个β粒子的三种放射性衰变过程的统称。

According to the experiment, the characteristics of the spontaneous emission spectra are analyzed.

结合实验，对激光器的自发发射谱的特性进行了研究。

It contributes to the noise figure of the EDFA which causes loss of signal-to-noise ratio.

放大的自发发射可以对引起信噪比损耗的EDFA噪声指数产生影响。

Spontaneous emission can be modified through controlling the Rabi frequency of the driving field.

通过改变驱动场的拉比频率可以达到控制原子自发发射的目的。

We have studied the properties of spontaneous emission from a three level atom embedded in a photonic crystal.

研究了三维光子晶体中三能级原子自发发射的性质。

The spontaneous emission of a four-level atom embedded in a one-dimensional photonic crystal is investigated.

本文研究了处于各向同性的一维光子晶体中的单个四能级原子的自发发射性质。

In this dissertation, InGaAs/InGaAsP/InP MQW microdisk laser and its characterization were presented. Some conclusions are as following: the characteristics of lasing threshold was discussed by using rate equation. The dependent relations between threshold and cavity volume, spontaneous emission coupling efficiency β were investigated. The whispering gallery mode and spontaneous emission in a microdisk geometry were then studied. Almost all spontaneous emission was coupled into the lowest order TE mode when the normalized thickness of photonics well was between 0.15 and 0.5. The design principle and device process of InGaAs/InGaAsP/InP MQW microdisk laser were presented. The microdisk lasers with the diameter of 8μm, 4. 5μm and 2μm were succesfully fabricated by using etching techniques. The pulse lasing thresholds for the microdisk with the diameter of 8μm and 4. 5μm were 170μW and 15μW, a record results compared with the published in the literature. The cw lasing threshold for a 2-μm-diameter microdisk was only a few μW. We haven't found similar report up to now. To solve the problem of directional output in a microdisk laser, the power coupling efficiency in a double disk geometry was investigated with the theory of waveguide mode couple. A new structure of electrically pumped microdisk laser with output waveguide was designed, making a foundation for the practical use of microdisk laser.

本文主要研究InGaAs/InGaAsP/InP多量子阱半导体碟型激光器的研制和特性表征，并取得如下结果：利用速率方程理论讨论了激光器激射阈值的特性，分析了阈值与腔体积和自发发射耦合系数β之间的关系；讨论了微碟光子阱结构中的自发发射特性和微碟中WGM模式特性；光子阱结构在其归一化厚度在0.15-0.5之间时，几乎全部自发发射进入到最低阶TE模式中；研究了InGaAs/InGaAsP/InP多量子阱微碟激光器的结构设计原理和器件的制备工艺；利用刻蚀方法成功制备出直径分别为8μm、4.5μm、2μm的碟型微腔激光器；直径8μm和4.5μm的微碟脉冲光泵浦激射阈值分别为170μW、15μW，是目前所见文献报导中比较低的；直径2μm的微碟连续光泵浦激射阈值仅几μW，目前尚未见到达到类似结果的研究报导；为解决微碟激光器激射光定向引出的问题，通过波导耦合模理论分析了双层碟之间功率耦合效率；据此设计了新型带耦合输出波导的电泵浦微腔激光器，为进一步研制可实用的电泵浦微腔激光器打下基础。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。