期刊文献+

二次检索

题名
关键词
文摘
作者
第一作者
机构
刊名
分类号
参考文献
作者简介
基金资助
栏目信息

机构

共找到5篇文章
< 1 >
每页显示 20 50 100
Optimization and Analysis of Magnesium Doping in MOCVD Grown p-GaN
1
作者 张晓敏 王彦杰 +7 位作者 杨子文 廖辉 陈伟华 李丁 李睿 杨志坚 张国义 胡晓东 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2008年第8期1475-1478,共4页
p-type conductivity and crystal quality of Mg-doped GaN grown by MOCVD have been improved through opti- mization of the magnesium flow rate. The hole concentration first increased and then decreased with the magnesium... p-type conductivity and crystal quality of Mg-doped GaN grown by MOCVD have been improved through opti- mization of the magnesium flow rate. The hole concentration first increased and then decreased with the magnesium flow rate while the mobility decreased monotonously. The optimum sample reached a hole concentration of 4. 1×10^17cm -3 and a resistivity of 1Ω·cm. Based on a self-compensation model involving the deep donor Mo, VN, we calculate the hole con- centration as a function of magnesium doping concentration NA ,which indicates that the self-compensation coefficient in- creases with NA;the hole concentration first increases with NA and reaches a maximum at NA≈4×10^19 ,then decreases rapidly as doping concentration increases. XRD also indicate that dislocation density decreased as magnesium flow rate decreased. 展开更多
关键词 P-GAN self-compensations magnesium doping MOCVD
下载PDF
High gain fiber-solid hybrid double-passing end-pumped Nd:YVO4 picosecond amplifier with high beam quality 被引量:1
2
作者 Xueyan Dong Pingxue Li +1 位作者 Shun Li Dongsheng Wang 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第5期273-281,共9页
We propose a fiber-solid hybrid system which consists of a semiconductor saturable absorber mirror(SESAM)modelocked fiber seed with a pulse width of 10.2 ps and a repetition rate of 18.9 MHz,a two-level fiber pre-ampl... We propose a fiber-solid hybrid system which consists of a semiconductor saturable absorber mirror(SESAM)modelocked fiber seed with a pulse width of 10.2 ps and a repetition rate of 18.9 MHz,a two-level fiber pre-amplifier and a double-passing end-pumped Nd:YVO4 amplifier.In the solid-state amplifier,to enhance the gain and the extraction efficiency,a specially designed structure in which the seed light passes through the gain medium four times and makes full use of population inversion is used as the double-passing amplifier.Besides,the beam filling factor(the ratio of the seed light diameter to the pump light diameter)and the thermal lens effect of the double-passing amplifier are considered and its optical-to-optical conversion efficiency is further improved.To preserve the beam quality of the double-passing amplifier,a new method of spherical-aberration self-compensation based on the principles of geometrical optics is used and discussed.Our system achieves a maximum average power of 9.5Wat the pump power of 28W,corresponding to an optical-to-optical efficiency of 27%.And the beam quality factor M^2 reaches 1.3 at the maximum output power. 展开更多
关键词 picosecond fiber-solid hybrid double-passing amplifier high beam quality spherical-aberration self-compensation
下载PDF
A New 1-V Second-Order Temperature-Compensated Current Reference
3
作者 易俊 张波 +1 位作者 方健 李肇基 《Journal of Electronic Science and Technology of China》 2004年第1期30-34,共5页
A new bipolar temperature-compensated current reference is proposed. The first-order temperature compensation is achieved by the idea of self temperature-compensation configuration exploiting the temperature coefficie... A new bipolar temperature-compensated current reference is proposed. The first-order temperature compensation is achieved by the idea of self temperature-compensation configuration exploiting the temperature coefficient of a combined resistor. The second-order compensation employs a VBE-tracking thermal-startup technique to obtain improved temperature performance. The proposed circuit can operate down to a 1-V supply. A temperature coefficient of 46.6×10?6/℃ [0, 100℃] at a 1-V supply and a supply regulation of 0.036%/V at 25℃ are achieved. Compared with present works, the proposed circuit shows better results of the temperature coefficient and supply regulation. The current matching issue frequently encountered in current references is also discussed in detail. 展开更多
关键词 1-V current reference self-compensATION second-order compensation current matching
下载PDF
One Novel Type of Miniaturization FBG Rotation Angle Sensor With High Measurement Precision and Temperature Self-Compensation 被引量:2
4
作者 Shanchao JIANG Jing WANG Qingmei SUI 《Photonic Sensors》 SCIE EI CAS CSCD 2018年第1期88-96,共9页
In order to achieve rotation angle measurement, one novel type of miniaturization fiber Bragg grating (FBG) rotation angle sensor with high measurement precision and temperature self-compensation is proposed and stu... In order to achieve rotation angle measurement, one novel type of miniaturization fiber Bragg grating (FBG) rotation angle sensor with high measurement precision and temperature self-compensation is proposed and studied in this paper. The FBG rotation angle sensor mainly contains two core sensitivity elements (FBG1 and FBG2), triangular cantilever beam, and rotation angle transfer element. In theory, the proposed sensor can achieve temperature self-compensation by complementation of the two core sensitivity elements (FBG1 and FBG2), and it has a boundless angel measurement range with 2π rad period duo to the function of the rotation angle transfer element. Based on introducing the joint working processes, the theory calculation model of the FBG rotation angel sensor is established, and the calibration experiment on one prototype is also carried out to obtain its measurement performance. After experimental data analyses, the measurement precision of the FBG rotation angle sensor prototype is 0.2° with excellent linearity, and the temperature sensitivities of FBG1 and FBG2 are 10 pro2℃ and 10.1 pm/℃, correspondingly. All these experimental results confirm that the FBG rotation angle sensor can achieve large-range angle measurement with high precision and temperature self-compensation. 展开更多
关键词 Rotation angle FBG temperature self-compensation
原文传递
Design and Investigation of a High-Sensitivity Tilt Sensor Based on FBG 被引量:2
5
作者 Jianjun PAN Liangying WANG +1 位作者 Wei HOU Hanyang Lv 《Photonic Sensors》 SCIE EI CSCD 2023年第2期45-55,共11页
In this paper,a high-sensitivity fiber Bragg grating(FBG)tilt sensor using a cantilever-based structure is introduced.Two FBGs are fixed on a specially designed elastomer.One end of the elastomer is connected to the m... In this paper,a high-sensitivity fiber Bragg grating(FBG)tilt sensor using a cantilever-based structure is introduced.Two FBGs are fixed on a specially designed elastomer.One end of the elastomer is connected to the mass block,and the other end is connected to the shell.The principle of the tilt sensor is introduced in detail,and the mathematical model is established.The performance of the sensor is studied.The results show that there is a good linear relationship between the central wavelength difference of the two FBGs and the tilt angle in the range of-5°to 5°.The repeatability of the sensor is good,and the tilt sensitivity can reach 231.7 pm/°.The influence of the silicone oil on the damping capacity of the sensor is studied.The results show that the damping capacity of the sensor has been improved by sealing the silicone oil inside the shell of the sensor.The field test is carried out on a pier of an elevated bridge,and the result is good,which verifies the practicability of the sensor. 展开更多
关键词 Tilt sensor FBG temperature self-compensation silicon oil vibration damping
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部