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排序方式: 共有543条查询结果,搜索用时 15 毫秒
61.
In this paper, a novel high-frequency/high-power field-effect-transistor structure is presented to reduce gain degradation caused by common-source inductance. In this structure, the reduction in common-source inductance is achieved without the need for using very thin substrates or very complicated fabrication technology, such as vias under each source finger. Using detailed transmission-line modeling, it is shown that a significant reduction in common-source inductance and improvement in RF performance can be achieved even for moderately high values of source grounding via inductance. The new structure allows simpler fabrication technology and is expected to be particularly useful to reduce the cost and improve the performance of high-power microwave and millimeter-wave devices and circuits 相似文献
62.
63.
V. Sriram 《国际自然能源杂志》2018,39(1):51-53
Energy is the key driver of the economy but energy crisis is a problem for the present-day source of energy. The concentrated solar power systems make use of different reflector configurations to convert the solar energy into high-temperature heat energy. Parabolic dish system is considered as the best suitable system for achieving high temperature and so it is opted for the study. Here, a solar dish is designed with an open diameter of 1.8?m (which is 2.5?m2 in area), and reflective film is being used to reflect the solar irradiance and concentrated it in the focal point. A receiver of 1?mm thickness and 10?cm diameter is used at the receiver end to measure the temperature of the focal point. The setup has made to attain a maximum temperature of 940°C and average temperature of 850°C in the focal point at clear sky in a sunny day. 相似文献
64.
In the present work, the shell and tube heat exchanger (STHX) is designed based on The Tubular Exchanger Manufacturers Association standards with hot fluid (water) flowing on the shell side and cold fluid on the tube side. A comparison is made between the Nusselt number and friction factor obtained from numerical and experimental results of segmental baffles (SBs) and helical baffles (HB) with different baffle inclinations. The results show that SB provided a higher Colburn factor (js) when compared with HBs STHXs (20°, 30°, 40°, and 50°), but shell side pressure drop is lower for 40° HBs STHXs for the same shell side fluid flow rates. 相似文献
65.
66.
Sriram Devanathan Derrick K. Rollins Stephen B. Vardeman 《Computers & Chemical Engineering》2000,24(12):460-2764
This work presents a technique that can completely and accurately identify measurement bias in cases where it is not possible to use the method of Rollins and Davis (1992, 1993) and where the method of Narasimhan and Mah (1987) fail to perform accurately. This technique makes use of information contained in the relationship between individual measurements and the corresponding nodal imbalance. The performance of this method is demonstrated on a problem from the literature that has been difficult for other methods to handle. In addition, this article discusses how the new technique can be used as a visual monitoring tool for identifying biased measured variables. 相似文献
67.
T.N. Sriram 《Sequential Analysis》2013,32(3-4):247-252
Sequential bootstrapping for branching processes with immigration is proposed. The asymptotic validity of a sequential bootstrap estimator of the offspring mean in is estabilished for all values of m ? (0, 1]. This result is to be constrasted with the standard (non-sequential)bootstrapping where the bootstrap estimator estimator has been shown to asymptotically invalid (see, Sriram (1992)). 相似文献
68.
Wireless networks play a very important role in today’s modern world, convincingly surpassing the wired infrastructure in
terms of popularity. Hence, it is important to ensure that services which access wired networks should also be accessible
using a wireless network without any performance degradation. One of the most common variants in wireless communications is
the Wireless Mesh Network (WMNs). WMNs exploit multi-hop wireless communications between wireless access points. Hence, the
effective bandwidth decreases as the number of hops increases in a WMN, thus increasing latency and resulting in reduced performance.
This may be due to spatial contention, multipath fading, interference or inefficient queuing mechanisms etc. Here we take
queuing mechanisms into consideration and study the QMMN algorithm (Queue Management for Multi-hop Networks) which tends to
improve throughput, fairness and reduce global synchronization problems. Based on our study, we implement a modified version
of the QMMN algorithm, otherwise called the Enhanced QMMN (EQMMN) algorithm. EQMMN can be considered an effective algorithm
which solves the problem of fairness between flows (either responsive or unresponsive) and eventually improves TCP throughput
at wireless access points. Our experimental results prove that EQMMN algorithms have better performance characteristics such
as throughput (TCP) and fairness index compared to QMMN algorithms. 相似文献
69.
The stator winding current commutation timing is the central subject of switched reluctance motor control. The direct use of coil inductance information for current commutation is introduced in this paper. The drawbacks of position-based commutation, in the presence of drifting electrical parameters, are overcome by using the instantaneous coil inductance information. Algorithms to optimize torque using this approach are also presented in this paper 相似文献
70.
Ehsani M. Husain I. Ramani K.R. Galloway J.H. 《Power Electronics, IEEE Transactions on》1993,8(2):224-230
A modified converter topology for star-connected switched reluctance motors suitable for low-voltage applications is proposed. A dual-time-constant freewheeling circuit has been designed to improve the drive performance and efficiency over a wide range of speeds. The different modes of operation of the converter are discussed, and a comparison is made with other converter configurations 相似文献