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A new iterative algorithm for geolocating a known altitude target using TDOA and FDOA measurements in the presence of satellite location uncertainty

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Chinese Journal of Aeronautics 2015年第5期28卷 1510-1518页

作者： Cao Yalu Peng li li jinzhou Yang Le Guo Fucheng School of Internet of Things (Io T) Engineering Jiangnan University College of Electronic Science and Engineering National University of Defense Technology Synergetic Innovation Center of Food Safety and Nutrition

This paper considers the problem of geolocating a target on the Earth surface whose altitude is known previously using the target signal time difference of arrival （TDOA） and frequency difference of arrival （FDOA） measurements obtained at satellites. The number of satellites available for the geolocation task is more than sufficient and their locations are subject to random errors. This paper derives the constrained Cramor-Rao lower bound （CCRLB） of the target position, and on the basis of the CCRLB analysis, an approximately efficient constrained maximum likelihood estimator （CMLE） for geolocating the target is established. A new iterative algorithm for solving the CMLE is then proposed, where the updated target position estimate is shown to be the globally optimal solution to a generalized trust region sub-problem （GTRS） which can be found via a simple bisection search. First-order mean square error （MSE） analysis is conducted to quantify the performance degradation when the known target altitude is assumed to be precise but indeed has an unknown but deterministic error. Computer simulations are used to compare the performance of the proposed iterative geolocation technique with those of two benchmark algorithms. They verify the approximate efficiency of the proposed algorithm and the validity of the MSE analysis.

关键词： Constrained Cram6r-Raolower bound (CCRLB):Frequency difference ofarrival (FDOA) Generalized trust regionsub-problem (GTRS):Performance analysis:Time difference of arrival(TDOA)

Source localization and calibration using TDOA and FDOA measurements in the presence of sensor location uncertainty

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Science China(Information Sciences) 2014年第4期57卷 156-167页

作者： li jinzhou GUO FuCheng JIANG Wenli School of Electronics Science and Engineering National University of Defense Technology

Source localization accuracy is very sensitive to sensor location *** paper performs analysis and develops a solution for locating a moving source using time difference of arrival(TDOA)and frequency difference of arrival(FDOA)measurements with the use of a calibration *** a Gaussian random signal model,we first derive the Cram′er-Rao lower bound(CRLB)for source location estimate in this *** we analyze the differential calibration technique which is commonly used in Global Positioning *** is indicated that the differential calibration cannot attain the CRLB accuracy in most cases.A closed-form solution is then proposed which takes a calibration emitter into account to reduce sensor location *** is shown analytically that under some mild approximations,our approach is able to reach the CRLB *** simulations are included to corroborate the theoretical developments.

关键词： source localization calibration time difference of arrival(TDOA) frequency difference of arrival(FDOA) sensor location uncertainty Cram′er-Rao lower bound(CRLB)

Constructing heterostructures of ZIF-67 derived C,N doped Co_(2)P and Ti_(2)VC_(2)T_(x)MXene for enhanced OER

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Journal of Materials Science & Technology 2023年第14期145卷 74-82页

作者： jinzhou li Chao Chen Zepeng Lv Wansen Ma Meng Wang Qian li Jie Dang College of Materials Science and Engineering Chongqing UniversityChongqing 400044China College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China State Key Laboratory of Advanced Special Steels&Shanghai Key Laboratory of Advanced Ferrometallurgy School of Materials Science and EngineeringShanghai UniversityShanghai 200444China

Oxygen evolution reaction(OER)is central to technologies such as electrochemical water splitting,and developing efficient and low-cost non-precious metal electrocatalysts for OER is of great significance to reducing cell voltage and developing hydrogen production by electrochemical water ***,we prepared a carbon,nitrogen co-doped porous Co_(2)P derived from the metal-organic framework(ZIF-67),which is anchored on bimetallic MXene nanosheets(named MX@MOF-Co_(2)P).It was used as the OER catalyst and exhibited great electrocatalytic performance with very small overpotentials(246 mV at 10 mA^(-2)and 407 mV at 200 mA cm^(-2))as well as ultralow Tafel slope(28.18 mV dec^(-1)).Combining charac-terizations and theoretical calculations,it was found that the remarkable performance was from follows:the obtained MX@MOF-Co_(2)P inherited the porous structure of the pristine MOF with a large number of open active sites;carbon and nitrogen doping also modulated the electronic structure of the active center;the synergistic effect between cobalt phosphide and MXenes booted the electronic *** work represents a promising strategy for the development of non-precious metal catalysts derived from metal-organic frameworks to achieve efficient energy conversion.

关键词： Mxene mof doping cobalt phosphide electrocatalysts

Interfacial electronic coupling of V-doped Co_(2)P with high-entropy MXene reduces kinetic energy barrier for efficient overall water splitting

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Journal of Energy Chemistry 2023年第10期85卷 301-309,I0009页

作者： Wansen Ma Zeming Qiu jinzhou li liwen Hu Qian li Xuewei Lv Jie Dang College of Materials Science and Engineering Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New MaterialsChongqing UniversityChongqing 400044China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China State Key Laboratory of Advanced Special Steels&Shanghai Key Laboratory of Advanced Ferrometallurgy School of Materials Science and EngineeringShanghai UniversityShanghai 200444China

Developing efficient,low-cost non-noble metal-based bifunctional catalysts to achieve excellent hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)kinetics in alkaline media is challenging but very ***,improving the electronic structure of the catalyst to optimize the adsorption of intermediates and reduce the reaction energy barrier is the key to improve the reaction ***,a V-doped Co_(2)P coupled with high-entropy MXene heterostructure catalyst(V-Co_(2)P@HE)was prepared by a two-step electrodeposition and controlled phosphorization *** analyses of X-ray absorption spectroscopy,X-ray photoelectron spectroscopy and theoretical calculations jointly show that the introduction of V and the strong electron coupling between the two components optimize the adsorption energy of water molecules and reaction *** from the abundant active sites and optimizing intermediate adsorption energy and heterogeneous interface electronic structure,V-Co_(2)P@HE has excellent HER and OER activity and long-term stability under alkaline *** particular,when assembled as cathode and anode,the bifunctional V-Co_(2)P@HE catalyst can drive a current density of 10 mA cm^(-2)with only 1.53 *** work provides new strategies for the application of highentropy MXene and the design of novel non-noble metal-based bifunctional electrolytic water catalysts.

关键词： Transition metal phosphides High-entropy MXene HER OER

Effects of synthesis methods on the performance of Pt + Rh/Ce_(0.6)Zr_(0.4)O_2 three-way catalysts

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Journal of Environmental Sciences 2014年第3期26卷 683-693页

作者： Zongcheng Zhan liyun Song Xiaojun liu Jiao Jiao jinzhou li Hong He Laboratory of Catalysis Chemistry and Nano-Science Department of Chemistry and Chemical Engineering College of Environmental and Energy Engineering Beijing University of Technology

The 0.7 wt% Pt ＋ 0.3 wt% Rh/Ce0.6Zr0.4O2 catalysts were fabricated via different methods, including ultrasonic-assisted membrane reduction （UAMR） co-precipitation, UAMR separation precipitation, co-impregnation, and sequential impregnation. The catalysts were physico-chemically characterized by N2 adsorption, XRD, TEM, and Hz-TPR techniques, and evaluated for three-way catalytic activities with simulated automobile exhaust. UAMR co-precipitation- and UAMR separation precipitation- prepared catalysts exhibited a high surface area and metal dispersion, wide λ window and excellent conversion for NOx reduction under lean conditions. Both fresh and aged catalysts from UAMR- precipitation showed the high surface areas of ca. 60-67 m^2/g and 18-22 m^2/g, respectively, high metal dispersion of 41%-55%, and small active particle diameters of 2.1-2.7 nm. When these catalysts were aged, the catalysts prepared by the UAMR method exhibited a wider working window （△λ = 0.284--0.287） than impregnated ones （△λ = 0.065-0.115） as well as excellent three-way catalytic performance, and showed lower/so （169℃） and T90 （195℃） for NO reduction than the aged catalysts from impregnation processes, which were at 265 and 309℃, respectively. This implied that the UAMR-separation precipitation has important potential for industrial applications to improve catalytic performance and thermal stability. The fresh and aged 0.7 wt% Pt ＋ 0.3 wt% Rh/Ce0.6Zr0.4O2 catalysts prepared by the UAMR-separation precipitation method exhibited better catalytic performance than the corresponding catalysts prepared by conventional impregnation routes.

关键词： UAMRthree way catalyst Pt and Rh nanoparticles precipitation thermal stability

Water‑immersion softening mechanism of coal rock mass based on split Hopkinson pressure bar experiment

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International Journal of Coal Science & Technology 2022年第4期9卷 122-134页

作者： Zhiyuan liu Gang Wang jinzhou li Huaixing li Haifeng Zhao Hongwei Shi Jianli Lan School of Petroleum Engineering China University of PetroleumBeijingBeijing 102249China Mine Disaster Prevention and Control-Ministry of State Key Laboratory Breeding Base Shandong University of Science and TechnologyQingdao 266590China College of Safety and Environmental Engineering Shandong University of Science and TechnologyQingdao 266590China

The coal mining process is afected by various water sources such as groundwater and coal seam water *** the dynamic mechanical parameters of water-immersed coal is helpful for coalmine safe *** impact compression tests were performed on coal with diferent moisture contents by using theϕ50 mm Split Hopkinson Pressure Bar(SHPB)experimental system,and the dynamic characteristics and energy loss laws of water-immersed coal with diferent compositions and water contents were *** analysis and discussion,it is found that:(1)When the moisture content of the coal sample is 0%,30%,60%,the stress,strain rate and energy frst increase and then decrease with time.(2)When the moisture content of the coal sample increases from 30%to 60%,the stress“plateau”of the coal sample becomes more obvious,resulting in an increase in the compressive stress stage and a decrease in the expansion stress stage.(3)The increase of moisture content of the coal sample will afect its impact deformation and failure *** the moisture content is 60%,the incident rod end and the transmission rod end of the coal sample will have obvious compression failure,and the middle part of the coal sample will also experience expansion and deformation.(4)The coal composition ratio suitable for the coal immersion softening impact experiment is optimized.

关键词： Coal immersion softening Dynamic compressive response Split Hopkinson pressure bar Softening mechanism model

TiO_(2)@NH_(2)-MIL-125(Ti) composite derived from a partial-etching strategy with enhanced carriers' transfer for the rapid photocatalytic Cr(Ⅵ) reduction

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International Journal of Minerals,Metallurgy and Materials 2023年第4期30卷 630-641页

作者： Fang Xu Wanning Cao jinzhou li Songsong Zhi Zhiyong Gao Yuqin Jiang Wei li Kai Jiang Dapeng Wu Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals Key Laboratory of Green Chemical Media and ReactionsMinistry of EducationSchool of Chemistry and Chemical EngineeringHenan Normal UniversityXinxiang 453007China School of Environment Henan Normal UniversityXinxiang 453007China

Metal-organic frameworks (MOFs)-based composites have been widely applied as photocatalysts because of their synergistic effect between the two individual ***,TiO_(2)@NH_(2)-MIL-125(Ti) nanocomposites which possess unsaturated titanium–oxo clusters,mesoporous structure,and intimate interface were successfully constructed via an in-situ distilled water-etched *** X-ray photoelectron spectroscopy (XPS) measurements indicated strong electronic interaction between TiO_(2)and NH_(2)-MIL-125(Ti),confirming the formation of TiO 2@NH_(2)-MIL-125(Ti) *** and thermodynamics measurements showed that TiO_(2)@NH_(2)-MIL-125(Ti)nanocomposites have improved charge separation efficient and decreased transfer resistance of the carriers within the heterojunction interfaces,which facilitates the photoexcited electrons transfer and reduction of the Cr(VI) ***,the optimal TiO_(2)@NH_(2)-MIL-125(Ti)nanocomposite demonstrated superior performance compared to NH_(2)-MIL-125(Ti) and NH_(2)-MIL-125(Ti) derived TiO_(2).Based on the free radical trapping experiment and electron paramagnetic resonance (EPR) measurements,a possible type-II scheme was proposed for the enhanced photocatalytic activity over the TiO_(2)@NH_(2)-MIL-125(Ti) nanocomposite.

关键词： NH_(2)-MIL-125 titanium dioxide distilled water-etched route photocatalysis hexavalent chromium reduction

Novel synthetic approaches and TWC catalytic performance of flower-like Pt/CeO2

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Frontiers of Environmental Science & Engineering 2014年第4期8卷 483-495页

作者： Zongcheng ZHAN Xiaojun liU Dongzhu MA liyun SONG jinzhou li Hong HE Hongxing DAI Department of Chemistry and Chemical Engineering College of Environmental and Energy Engineering Beijing University of Technology Beijing 100124 China

A novel Ultrasonic Assisted Membrane Reduction （UAMR）-hydrothermal method was used to prepare flower-like Pt/CeO2 catalysts. The texture, physical/chemical properties, and reducibility of the flower-like Pt/CeO2 catalysts were characterized by X-Ray Diffraction （XRD）, Scanning Electron Microscope （SEM）, Transmission Electron Microscope （TEM）, N2 adsorption, and hydrogen temperature programmed reduction （HE-TPR） techniques. The catalytic performance of the catalysts for treating automobile emission was studied relative to samples prepared by the conventional wetness impregnation method. The Pt/CeO2 catalysts fabricated by this novel method showed high specific surface area and metal dispersion, excellent three-way catalytic activity, and good thermal stability. The strong interaction between the Pt nanoparticles and CeO2 improved the thermal stability. The Ce4＋ ions were incorporated into the surfactant chains and the Pt nanoparticles were stabilized through an exchange reaction of the surface hydroxyl groups. The SEM results demonstrated that the Pt/CeO2 catalysts had a typical three-dimensional （3D） hierarchical porous struc- ture, which was favorable for surface reaction and enhanced the exposure degree of the Pt nanoparticles. In brief, the flower-like Pt/CeO2 catalysts prepared by UAMR-hydrothermal method exhibited a higher Pt metal dispersion, smaller particle size, better three-way catalytic activity, and improved thermal stability versus conven- tional materials.

关键词： Ultrasonic Assisted Membrane Reduction (UAMR) Pt nanoparticles three-way catalyst flower-like

传感器位置误差条件下仅用到达频率差的无源定位性能分析

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航空学报 2011年第8期32卷 1497-1505页

作者：李金洲郭福成国防科学技术大学电子科学与工程学院湖南长沙410073

传感器自身的位置误差对辐射源的无源定位精度可能有较大影响,详细分析并推导了在存在传感器位置误差条件下,仅使用到达频率差(FDOA)参数对辐射源定位时,定位精度的克拉美罗下限(CRLB)和均方误差(MSE)。在传感器位置误差条件下,提出仅用... 详细信息

传感器自身的位置误差对辐射源的无源定位精度可能有较大影响,详细分析并推导了在存在传感器位置误差条件下,仅使用到达频率差(FDOA)参数对辐射源定位时,定位精度的克拉美罗下限(CRLB)和均方误差(MSE)。在传感器位置误差条件下,提出仅用FDOA来同时估计辐射源和传感器位置的泰勒级数方法,并证明该定位方法理论上的MSE和CRLB一致。实验中在给定较好初始解的情况下,泰勒级数方法的估计精度基本上达到了CRLB,同时也验证了定位误差CRLB和MSE性能理论分析的正确性。

关键词：无源定位到达频率差泰勒级数克拉美罗下限均方误差