低功率

The results show that the ponderomotive force of high-power microwave would affect the dispersion,make the distribution of microwave different from Bessel distribution,and drive the plasma to the region where the microwave field is lower.

结果表明高功率微波的有质动力将影响微波色散特性，使微波场强分布偏离Bessel分布，并对等离子体有排开作用，当场强足够大时可将波导中心处等离子体排空形成低密度通道。

The appearance of heterojunction high electron mobility devices has made the new vigor poured into the development of GaAs MMICs. Pseudomorphic high electron mobility transistors have outstanding high-frequency characteristics, power characteristics and low-noise characteristics. And these merits have made the PHEMTs one of the most promising devices.

异质结高电子迁移率器件的出现给GaAs MMIC的发展注入了新的活力，赝配高电子迁移率晶体管具有优异的高频特性、功率特性和低噪声特性，使其成为现今微波单片集成电路发展中最具应用前景的器件之一。

The phenomena of improved confinement has been observed with ECRH auxiliary heating under limiter discharge condition on the HL-2A tokamak, and electron line average density, plasma stored energy, radiated power within the separatrix, energy confinement time, H-alpha line emission etc, have been studied for the transition from L-mode to improved mode.

在HL-2A装置孔栏位形放电的等离子体实验中，电子回旋辅助加热期间观察到了等离子体约束改善的现象，并对等离子体从低约束模式向约束改善模式转换时的等离子体线平均电子密度、等离子体储能、分界面内辐射功率、能量约束时间、H辐射等进行了研究。

Although reducing the number of fins increases thermal resistance and the substract temperature, the measured data indicates that the thermal resistance of the road lamp is low enough to ensure sufficient cooling capability and safety chip temperature at the rated operating power.

减少散热鳍片的数量虽然会增加热阻与铝基板的温度，但是实验数据显示本灯具的散热路径热阻甚低，足以提供本灯具在额定功率的散热性能，确保晶片维持在安全的工作温度。

The device is able to handle an unclamped current during its normal operation, assuring self protection against voltage surges, PCB stray inductance, and allowing a snubberless operation for low output power.

该设备能够处理的非钳位电流在正常运行，保证对电压的自我保护，印刷电路板寄生电感，和允许低输出功率缓冲器运作。

With the support of a major research grant of Zhejiang Province (No. 001101027) and the Plan of Promoting Education of Excellence of Zhejiang University in the 21st Century, this dissertation is devoted to address the above problems and fabricate an L-band EDFA with low cost, high performance and technological innovation.First the mechanism of an erbium doped fiber amplifier is introduced. Various theoretical models based on classical rate propagation equations are summarized and compared for their applications. We use a modified numerical model based on the Giles model, which agrees with the experimental results well. This serves as the theoretical base for the whole thesis and will be used to optimize the characteristics of EDFAs. A novel method based on a map of noise figure and gain is proposed to analyze efficiently the dependence of the noise figure and gain for EDFAs on the EDF length and the pump power. The characteristics of various EDFAs are studied and compared.Secondly, some important parameters are introduced to describe the characteristics of EDFAs. The methods and the experimental setups for measuring the gain and noise figure of an EDFA are emphasized. We introduce how to measure the characteristics of each component of an EDFA, especially the gain and absorption coefficient of an erbium doped fiber.Thirdly, four types of simple and novel L-band EDFA structures with low noise, high gain and low gain ripple are proposed to satisfy the requirement of a DWDM system. They can be classified into two categories. In the first category, a single ASE pumping is served asa secondary pump. This category includes the following three types. Type: a new construction using a fiber Bragg grating in an unpumped EDF section at the input side. Type: a new structure of L-Band EDFA with two-stage pumps, which utilizes the forward ASE as a second pump.

本论文本着科技创新、服务于生产实践的精神，以设计价格低廉，性能优越、结构合理简单的L-band EDFA为目标，依托浙江省科技厅重大科学基金资助项目(001101027)和浙江大学振兴教育计划资助的全光网络的搭建—《光通信技术》课程实验建设项目，展开了如下工作：首先，介绍了掺铒光纤放大器的工作原理，归纳总结了基于速率方程基础的EDFA的各种理论模型，分析比较了各个模型的特点和适用场合，最终选择完善的Giles理论模型作为本论文分析设计EDFA的理论基础；针对实际实验条件提出了修正的EDFA模型的数值计算方法；创新地提出了增益—噪声系数全局分析法，直观有效地分析了EDFA的增益和噪声系数与掺铒光纤长度和泵浦功率的依赖关系，并对各种EDFA的性能作了全面的比较；第二，介绍了掺铒光纤放大器特性参数的定义与测量方法，重点介绍了噪声系数和增益系数的测量方法及实验装置；介绍了组成掺铒光纤放大器各组件的特性测量方法，重点介绍了测量掺铒光纤参数的方法和实验装置；第三，针对WDM系统对L-band EDFA谱平坦、低噪声、高增益的要求，我们创新地提出了四种不同的L-band EDFA结构，按设计思路可以分为两大类：一类是基于单抽运二级泵浦法，这一类包括在未泵浦掺铒光纤的输入端插入一根布拉格光纤光栅的两段L-band的EDFA的新结构；基于前向ASE光作为二级泵浦源推动下一级EDF工作的泵浦分配、两段级联L-band的EDFA的新结构；基于单根光纤光栅、泵浦分配、两段级联的EDFA；另一类则是基于同时应用前后向C-band ASE作二级泵浦源的双抽运法，如基于前后向ASE光作为二级泵浦源的三段级联L-band的EDFA的新结构。

It has big power,and multipe air exhaustor.and fixed,insideontside water circulation,can be with five tap for suction direct display at the same time,The pump has the advantages of unuse oil,non-pollution,big power,lower noise,easy movement, save waterelectricity one machine with multi-usage.

该泵是大功率多头抽气的一种新型不锈钢循环水式多用真空泵，本机设计内外循环水，可以五头同时抽气，具有不用油、无污染、功率大、噪音低、方便灵活，节水省电等优点，一机多用。

It has big power,and multipe air exhaustor.and fixed,inside and ontside water circulation,can be with five tap for suction direct display at the same time,The pump has the advantages of unuse oil,non-pollution,big power,lower noise,easy movement, save water and electricity one machine with multi-usage.

该泵是大功率多头抽气的一种新型不锈钢循环水式多用真空泵，本机设计内外循环水，可以五头同时抽气，具有不用油、无污染、功率大、噪音低、方便灵活，节水省电等优点，一机多用。

This pump is a new stainless stee multiusage vacuumpump with water circulation.it has big power,and multipe air exhaustor.and fixed,inside and ontside water circulation,can be with five tap for suction direct display at the same time,the pump has the advantages of unuse oil,non-pollution,big power,lower noise,easy movement, save water and electricity one machine with multi-usage.

该泵是大功率多头抽气的一种新型不锈钢循环水式多用真空泵，本机设计内外循环水，可以五头同时抽气，具有不用油、无污染、功率大、噪音低、方便灵活，节水省电等优点，一机多用。

It has big power,and multipe air exhaustor.and fixed,inside and ontside water circulation,can be with five tap for suction direct display at the same time,The pump has the advantages of unuse oil,non-pollution,big power,lower noise,easy movement, save water and electricity one machine with multi-usage.

油、无污染、功率大、噪音低、方便灵活，节水省电等优点，一机多用。

Plunder melds and run with this jewel!

掠夺melds和运行与此宝石！

My dream is to be a crazy growing tree and extend at the edge between the city and the forest.

此刻，也许正是在通往天国的路上，我体验着这白色的晕旋。