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We introduce a sub-cell WENO reconstruction method to evaluate spatial derivatives in the high-order ADER scheme. The basic idea in our reconstruction is to use only r stencils to reconstruct the point-wise values of solutions and spatial derivatives for the 2r-1 th order
ADER scheme in one dimension, while in two dimensions, the dimension-by-dimension sub-cell reconstruction approach for spatial derivatives is employed. compared with the original ADER scheme of Toro and Titarev (2002) [2] that uses the direct derivatives of reconstructed polynomials for solutions to evaluate spatial derivatives, our method not only reduces greatly the computational costs of the ADER scheme on a given mesh,
but also avoids possible numerical oscillations near discontinuities, as demonstrated by a number of one- and two-dimensional numerical tests. All these tests show that the 5th-order ADER scheme based on our sub-cell reconstruction method achieves the desired accuracy, and is essentially non-oscillatory and computationally cheaper for problems with discontinuities.
標簽：
高精度格式
上傳時間：
2016-01-13
上傳用戶：ccsdcczd
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We consider the problem of target localization by a
network of passive sensors. When an unknown target emits an
acoustic or a radio signal, its position can be localized with multiple
sensors using the time difference of arrival (TDOA) information.
In this paper, we consider the maximum likelihood formulation
of this target localization problem and provide efficient convex
relaxations for this nonconvex optimization problem.We also propose
a formulation for robust target localization in the presence of
sensor location errors. Two Cramer-Rao bounds are derived corresponding
to situations with and without sensor node location errors.
Simulation results confirm the efficiency and superior performance
of the convex relaxation approach as compared to the
existing least squares based approach when large sensor node location
errors are present.
標簽：
傳感器網(wǎng)絡
上傳時間：
2016-11-27
上傳用戶：xxmluo
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Multiple-Input Multiple-Output (MIMO) systems have recently been the
subject of intensive consideration in modem wireless communications as they
offer the potential of providing high capacity, thus unleashing a wide range of
applications in the wireless domain. The main feature of MIMO systems is the
use of space-time processing and Space-Time Codes (STCs). Among a variety
of STCs, orthogonal Space-Time Block Codes (STBCs) have a much simpler
decoding method, compared to other STCs
標簽：
Orthogonal
Space-Time
Processing
Complex
上傳時間：
2020-05-26
上傳用戶：shancjb
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The solid high-polymer-film-type fuel cell (PEM-FC) system is used as the power
supply equipment for transportation and replaces an internal combustion engine. A
reduction of the environmental load is expected through the cogeneration system’s
(CGS) use of the PEM-FC system as a distributed power supply to individual
houses, apartments, and so forth [1–3]. The growing use of distributed power
systems, such as fuel cells, the reduction of power-transmission losses, and an
increase of waste heat recovery are expected. Therefore, the reduction of carbon-
dioxide emission is also expected as compared to conventional energy supply
methods using commercial electric power.
標簽：
Micro-grids
Fuel
Cell
上傳時間：
2020-06-07
上傳用戶：shancjb
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GaN is an already well implanted semiconductor
technology, widely diffused in the LED optoelectronics
industry. For about 10 years, GaN devices have also been
developed for RF wireless applications where they can
replace Silicon transistors in some selected systems. That
incursion in the RF field has open the door to the power
switching capability in the lower frequency range and
thus to the power electronic applications.
compared to Silicon, GaN exhibits largely better figures
for most of the key specifications: Electric field, energy
gap, electron mobility and melting point. Intrinsically,
GaN could offer better performance than Silicon in
terms of: breakdown voltage, switching frequency and
Overall systems efficiency.
標簽：
GaN-on-Si
Displace
and
SiC
Si
上傳時間：
2020-06-07
上傳用戶：shancjb
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Battery systems for energy storage are among the most relevant technologies of the
21 st century. They – in particular modern lithium-ion batteries (LIB) – are enablers
for the market success of electric vehicles (EV) as well as for stationary energy
storage solutions for balancing fluctuations in electricity grids resulting from the
integrationofrenewableenergysourceswithvolatilesupply 1 .BothEVandstationary
storage solutions are important because they foster the transition from the usage
of fossil energy carriers towards cleaner renewable energy sources. Furthermore,
EV cause less local air pollution and noise emissions compared to conventional
combustion engine vehicles resulting in better air quality especially in urban areas.
Unfortunately, to this day, various technological and economic challenges impede a
broad application of batteries for EV as well as for large scale energy storage and
load leveling in electricity grids.
標簽：
Multiscale
Simulation
Approach
上傳時間：
2020-06-07
上傳用戶：shancjb
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溫度控制如今已成為當代社會研究的熱點之一,而溫度檢測在現(xiàn)代設備參數(shù)檢測中也是一項極其重要的技術,應用十分廣泛。與傳統(tǒng)的測溫方法相比,紅外測溫方法具有時間短、精度高、使用簡單方便等優(yōu)點。本文以環(huán)境溫度為被測對象,設計了以STC89C52單片機為控制中心的紅外測溫裝置,能夠實現(xiàn)對目標溫度的實時采集、處理、顯示和報警等功能。本設計主要是由STC89C52單片機、紅外測溫傳感器、LCD1602液晶顯示器、按鍵和蜂鳴器等部分組成,采用非接觸的方式對目標溫度進行實時檢測。Temperature control has become one of the hotspots in contemporary social research,and temperature detection is an extremely important technology in modern equipment parameter detection.compared with traditional method,the infrared temperature measuring method has advantages of short time,high precision and convenient operation,etc.This paper consider environment temperature as research objects and designs an infrared temperature measuring device which employs the STC89C52singlechipas-control center,and it can realize timely collection,processing,display and alarm function of the target temperature.The design is mainly composed of STC89C52 singlechip,infrared temperature sensor,LCD1602monitor,keys and buzzer,etc.This design detects the target temperature by non-contact method.
標簽：
單片機
紅外測溫
上傳時間：
2022-03-27
上傳用戶：jiabin
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通過采用無橋PFC和半橋LLC諧振變換器作為數(shù)字開關電源的主變換拓撲,基于STM32系列微控制器的全數(shù)字控制PFC和DC-DC變換器,首先對數(shù)字化開關電源方案進行對比,然后闡述了200W數(shù)字開關電源整體方案,并對數(shù)字開關電源的無橋PFC和半橋LLC變換器進行系統(tǒng)研究。By using a bridgeless PFC and a half-bridge LLC resonant converter as the main conversion topology of the digital switching power supply,the all-digital control PFC and DC-DC converter based on the STM32 series of microcontrollers,firstly the digital switching power supply scheme is compared,and then the overall scheme of 200 W digital switching power supply is expounded, and the bridgeless PFC and half-bridge LLC converter of digital switching power supply are systematically studied.
標簽：
數(shù)字開關電源
上傳時間：
2022-04-02
上傳用戶：qingfengchizhu
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針對目前MSP430單片機實驗裝置較少、實驗內容少,而且無MSP430高端產品的實驗裝置,研制了基于MSP430F5529單片機的綜合實驗裝置,主要包括MSP430 Launch Pad和母板兩部分。較傳統(tǒng)的單片機實驗裝置增加了模擬電路的設置,設計的實驗能夠利用單片機的所有外設,可進行模塊基礎實驗和綜合實驗兩大類實驗,非常適合自動化和電氣信息類大學生學習使用。Concerning with the lack of experimental equipment and content based on MSP430,and especially,the experimental equipment of MSP430 senior products,an experimental equipment based on MSP430F5529 microcontroller is developed. It mainly consists of two parts： MSP430 Launch Pad and main board. compared with traditional microcontroller experiment equipment,a few analog circuits were added. The experiment we set up takes advantage of all microcontroller peripherals. Students can do two kinds of experiments： module experiment and complex experiment.Therefore it fits university students in automation and electrical major very well.
標簽：
msp430f5529
單片機
上傳時間：
2022-04-13
上傳用戶：
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為適應雙向DC/DC功率變換的電流采樣需求,一種高精度高邊電流采樣電路被提出。其基本思想是在功率電路的高邊串入采樣電阻,借助電流鏡原理并引入偏置電流電路,將雙向電流均轉換為正向電壓輸出。通過理論分析與仿真結合的方法對電流鏡采樣原理及4種不同的偏置電流電路方案進行對比,最后通過實驗數(shù)據(jù)驗證了高精度高邊電流采樣電路的有效性。實驗數(shù)據(jù)表明,該采樣電路可在-25~75℃的溫度工作范圍內,針對-10~＋10 A范圍內的電流采樣實現(xiàn)優(yōu)于5%的采樣精度。Current sensing plays an important role in controlling,monitoring or protection functions of power systems.To meet the current sensing requirement of bidirectional DC/DC converters,a high-accuracy bidirectional current sensing circuit is proposed.The proposed current sensing circuit inserts a resistor in the path of the current to be sensed,while the current mirror and biased current circuit are introduced.Therefore,the bidirectional current can be expressed by positive voltage.By theoretical analysis and simulation,the sampling theory is analyzed and four biased current circuits are compared.At last,experimental results verified the proposed method.It is demonstrated that the proposed current sensing circuit can achi...
標簽：
雙向DC電源
電流采樣
上傳時間：
2022-04-22
上傳用戶：
