High speed, low noise ultraviolet photodetectors based on GaN p-i-n and AlGaN(p)-GaN(i)-GaN(n)structures

1997 ◽  
Vol 71 (15) ◽  
pp. 2154-2156 ◽  
Author(s):  
G. Y. Xu ◽  
A. Salvador ◽  
W. Kim ◽  
Z. Fan ◽  
C. Lu ◽  
...  
1999 ◽  
Vol 74 (5) ◽  
pp. 762-764 ◽  
Author(s):  
D. Walker ◽  
E. Monroy ◽  
P. Kung ◽  
J. Wu ◽  
M. Hamilton ◽  
...  

1998 ◽  
Vol 264-268 ◽  
pp. 1441-1444 ◽  
Author(s):  
G. Xu ◽  
A. Salvador ◽  
A.E. Botchkarev ◽  
W. Kim ◽  
C. Lu ◽  
...  

Machines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Jing Wang ◽  
Zhihua Wan ◽  
Zhurong Dong ◽  
Zhengguo Li

The harmonic reducer, with its advantages of high precision, low noise, light weight, and high speed ratio, has been widely used in aerospace solar wing deployment mechanisms, antenna pointing mechanisms, robot joints, and other precision transmission fields. Accurately predicting the performance of the harmonic reducer under various application conditions is of great significance to the high reliability and long life of the harmonic reducer. In this paper, a set of automatic harmonic reducer performance test systems is designed. By using the CANOpen bus interface to control the servo motor as the drive motor, through accurately controlling the motor speed and rotation angle, collecting the angle, torque, and current in real time, the life cycle test of space harmonic reducer was carried out in high vacuum and low temperature environment on the ground. Then, the collected data were automatically analyzed and calculated. The test data of the transmission accuracy, backlash, and transmission efficiency of the space harmonic reducer were obtained. It is proven by experiments that the performance data of the harmonic reducer in space work can be more accurately obtained by using the test system mentioned in this paper, which is convenient for further research on related lubricating materials.


Author(s):  
Vladimir Kondratjev ◽  
Vasily Litvinsky ◽  
Serhii Pohuliai ◽  
Stanislavs Lozkins

The results of engineering an intelligent preamplifier for HPGe gamma-detectors are presented. An intelligent preamplifier is a low-noise, high-speed resistive feedback charge-sensitive preamplifier with a built-in microcontroller and additional units that enable control of preamplifier and detector parameters. It also allows to manage performance of the internal testing pulser, sensor of liquid nitrogen level in Dewar, humidity, pressure and temperature sensors in a sealed preamplifier section. Intelligent preamplifier operation, setup and parameter measurements are controlled by a software.


2014 ◽  
Vol 49 (6) ◽  
pp. 1437-1447 ◽  
Author(s):  
Dan Li ◽  
Gabriele Minoia ◽  
Matteo Repossi ◽  
Daniele Baldi ◽  
Enrico Temporiti ◽  
...  

2005 ◽  
Vol 17 (8) ◽  
pp. 1719-1721 ◽  
Author(s):  
Ning Duan ◽  
Shuling Wang ◽  
Feng Ma ◽  
Ning Li ◽  
J.C. Campbell ◽  
...  

2021 ◽  
Vol 263 (5) ◽  
pp. 1574-1585
Author(s):  
Sebastian Sepp ◽  
Joshua Goetz ◽  
Karsten Stahl

The progressing electrification of vehicle drive systems focuses more and more on efficient high-speed concepts. Increasing the motor speed leads to a higher power density of the electrified power train and thereby to an increased range for battery electric vehicles. The high rotational speeds cause new challenges in designing gearboxes regarding the efficiency and the acoustical behavior. Most present gearings in conventional vehicles are designed with high tooth depths to ensure low noise excitation behavior combined with the best possible efficiency. By changing the gear geometry to smaller tooth depths with higher pressure angles, it is possible to further decrease gear losses. However, the loss-optimized gear geometry must not jeopardize the beneficial acoustical behavior. In theoretical studies, the acoustical behavior of loss-optimized gears are investigated and compared to gearings designed according to the state of the art. Design calculations of the excitations of all ideal gears without deviations are on similar levels. However, application of such gear geometries faces severe challenges because the sensitivity to manufacturing deviations may be high. In this paper, simulation results and test results between low-NVH gears and loss-optimized gears are documented and analyzed.


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