2013 ◽  
Vol 397-400 ◽  
pp. 536-545
Author(s):  
Luo Gang Li ◽  
Wu Xing Jing ◽  
Chang Sheng Gao

Since the maneuverability of the tactical ballistic missile, the midcourse trajectory of interception missile needs design online. Firstly, this paper reasonably simplifies the models and explores the analytical expressions of their relative motion state to obtain a kind of rapid and high-precision computing method of zero effort miss. Secondly, it applies constant thrust for the interception missile, burns out shut-down solid engine, reflects on the index requirement of overloaded interception missile, and designs midcourse trajectory of the interception missile with Pontryagin maximal principle, in accordance with the analytical expressions of zero effort miss. Finally, with the simulating calculation, the prediction methods of zero effort miss and trajectory design method provided by this paper are applied to a situation simulation which is close to the fact as much as possible so as to verify the applicability in the interception of tactical ballistic missile.


2014 ◽  
Vol 556-562 ◽  
pp. 1959-1963
Author(s):  
Si Ming Wei ◽  
Yi Gong Zhang ◽  
Huan Liu ◽  
Zhi Qiang Dai ◽  
Xiao Du

It is great significance for development of MTDC (Multi-terminal HVDC) to build DC transmission and distribution grids. However, the relatively low impedance in DC grids makes the fault penetration much faster and deeper .Consequently, fast and reliable DC circuit breaker is needed to isolate faults. Breaking time and other parameters are important for a breaker to achieve its goals. This paper presents a DC circuit breaker with a current-limiting inductance and gets the rising and falling characteristics of fault current. Based on the characteristics, a design method of breaking time sequence will be given, as well as the calculation of current-limiting inductance and the selection principles of arresters. A 10kV DC distribution grid is modeled and simulated by PSCAD/EMTDC to verify that the method can meet the requirements of breaking fault current quickly and reliably.


2016 ◽  
Vol 64 (2) ◽  
pp. 301-306 ◽  
Author(s):  
B. Pankiewicz

Abstract In this paper the multiple output current amplifier basic cell is proposed. The triple output current mirror and current follower circuit are described in detail. The cell consists of a split nMOS differential pair and accompanying biasing current sources. It is suitable for low voltage operation and exhibits highly linear DC response. Through cell devices scaling, not only unity, but also any current gains are achievable. As examples, a current amplifier and bandpass biquad section designed in CMOS TSMC 90nm technology are presented. The current amplifier is powered from a 1.2V supply. MOS transistors scaling was chosen to obtain output gains equal to -2, 1 and 2. Simulated real gains are -1.941, 0.966 and 1.932 respectively. The 3dB passband obtained is above 20MHz, while current consumption is independent of input and output currents and is only 7.77μA. The bandpass biquad section utilises the previously presented amplifier, two capacitors and one resistor, and has a Q factor equal to 4 and pole frequency equal to 100 kHz.


2016 ◽  
Vol 848 ◽  
pp. 205-209 ◽  
Author(s):  
Bin Zhang ◽  
Benjamin Ducharne ◽  
Jun Gao

Energy harvesting from ambient environment vibration is a potential method to supply the low-power consumption devices. This paper demonstrates a new method to proceed energy harvesting using a piezoceramic. Both the mechanical and electrical excitations (hybrid stimulation) have been exerted on a piezoceramic. Current was measured though a current amplifier to calculate the induced polarization. By comparing the hybrid stimulation and the pure mechanical one, it can be found that the hybrid stimulation method enable to amplifier the harvested energy, which is promising to be used in energy harvesting and sensor applications.


2016 ◽  
Vol 67 (4) ◽  
pp. 261-266 ◽  
Author(s):  
Josef Polak ◽  
Jan Jerabek ◽  
Lukas Langhammer ◽  
Roman Sotner ◽  
Jan Dvorak ◽  
...  

Abstract This paper presents the simulations results in comparison with the measured results of the practical realization of the multifunctional second order frequency filter with a Digitally Adjustable Current Amplifier (DACA) and two Dual-Output Controllable Current Conveyors (CCCII +/−). This filter is designed for use in current mode. The filter was designed of the single input multiple outputs (SIMO) type, therefore it has only one input and three outputs with individual filtering functions. DACA element used in a newly proposed circuit is present in form of an integrated chip and the current conveyors are implemented using the Universal Current Conveyor (UCC) chip with designation UCC-N1B. Proposed frequency filter enables independent control of the pole frequency using parameters of two current conveyors and also independent control of the quality factor by change of a current gain of DACA.


2011 ◽  
Vol 1282 ◽  
Author(s):  
Joan E. Yater ◽  
Jonathan L. Shaw ◽  
Kevin L. Jensen ◽  
Tatyana Feygelson ◽  
Robert E. Myers ◽  
...  

ABSTRACTHigh-current-density cathodes are required for the development of high-power mm-wave and upper mm-wave devices, as well as for other electron beam applications. To address this need, a current amplifier stage is being developed that will multiply a primary electron-beam current (via the secondary-electron multiplication process) and then emit the amplified beam so as to achieve a current gain of 50-100. Diamond is a particularly promising current amplification source due to the negative electron affinity present at stable hydrogenated surfaces. As such, we are fabricating current amplifiers using single-crystal CVD diamond grown at NRL, with our growth effort focused on reducing the impurity concentration in the epitaxial diamond and on fabricating microns-thick freestanding films. The current amplification characteristics of the diamond films are examined using secondary-electron-emission measurements in both reflection and transmission configurations. In our initial study of an 8.3-µm-thick CVD diamond film, the single-crystal diamond is shown to have superior transport and emission properties compared to similar polycrystalline material. While transmission gains have been obtained under field-free conditions from the unbiased diamond film, we are striving to increase the gain by increasing the transport efficiency in a biased amplifier structure. Towards this end, recent efforts have focused on optimizing the bonding and metallization processes as needed to establish and control the internal electric field. In addition, Monte Carlo simulations are being used to predict the optimal material and device parameters needed to achieve high amplifier gain and low energy spread.


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