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Dynamic State Estimation of Medium-voltage DC Integrated Power System with Pulse Load

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Journal of Modern Power Systems and Clean Energy 2020年第4期8卷 689-698页

作者： Runlong Xiao Gang Wang xiaoliang Hao Renji Huang Youxing Xiong National Key Laboratory of Science and Technology on Vessel Integrated Power System Naval University of EngineeringWuhan 430033China

The dynamic characteristic evaluation is an important prerequisite for safe and reliable operation of the mediumvoltage DC integrated power system(MIPS),and the dynamic state estimation is an essential technical approach to the *** the electromechanical transient process in a traditional power system,periodic change in pulse load of the MIPS is an electromagnetic transient *** the system state suddenly changes in the range of a smaller time constant,it is difficult to estimate the dynamic state due to periodic *** paper presents a dynamic mathematical model of the MIPS according to the network structure and control strategy,thereby overcoming the restrictions of algebraic variables on the estimation and developing a dynamic state estimation method based on the extended Kalman *** the method of adding fictitious process noise,it is possible to solve the problem that the linearized algorithm of the MIPS model is less reliable when an abrupt change occurs in the pulse ***,the accuracy of the dynamic state estimation and the stability of the filter can be improved under the periodic disturbance of pulse *** simulation and experimental results confirm that the proposed model and method are feasible and effective.

关键词： Medium-voltage DC integrated power system pulse load dynamic state estimation extended Kalman filter fictitious process noise

MC-LRF based pose measurement system for shipborne aircraft automatic landing

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Chinese Journal of Aeronautics 2023年第8期36卷 298-312页

作者： Zhuo ZHANG Qiufu WANG Daoming BI xiaoliang SUN Qifeng YU College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China AVIC Shenyang Aircraft Design&Research Institute Shenyang 110850China

Due to the portability and anti-interference ability,vision-based shipborne aircraft automatic landing systems have attracted the attention of *** this paper,a Monocular Camera and Laser Range Finder(MC-LRF)-based pose measurement system is designed for shipborne aircraft automatic ***,the system represents the target ship using a set of sparse landmarks,and a two-stage model is adopted to detect landmarks on the target *** rough 6D pose is measured by solving a Perspective-n-Point ***,once the rough pose is measured,a region-based pose refinement is used to continuously track the 6D pose in the subsequent image *** address the low accuracy of monocular pose measurement in the depth direction,the designed system adopts a laser range finder to obtain an accurate range *** measured rough pose is iteratively optimized using the accurate range *** results on synthetic and real images show that the system achieves robust and precise pose measurement of the target ship during automatic *** measurement means error is within 0.4in rotation,and 0.2%in translation,meeting the requirements for automatic fixed-wing aircraft landing.

关键词： Automatic landing Dataprocessingand image processing Laser range finder Monocular camera Pose measurement

A New Coupled Complex BoundaryMethod for Bioluminescence Tomography

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Communications in Computational Physics 2016年第1期19卷 226-250页

作者： Rongfang Gong xiaoliang Cheng Weimin Han Department of Mathematics Nanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Mathematics Zhejiang UniversityHangzhou 310027China Department of Mathematics University of IowaIowa CityIA 52242USA School of Mathematics and Statistics Xi’an Jiaotong UniversityXi’an 710049China

In this paper,we introduce and study a new method for solving inverse source problems,through aworkingmodel that arises in bioluminescence tomography(BLT).In the BLT problem,one constructs quantitatively the bioluminescence source distribution inside a small animal from optical signals detected on the animal’s body *** BLT problem possesses strong ill-posedness and often the Tikhonov regularization is used to obtain stable approximate *** conventional Tikhonov regularization,it is crucial to choose a proper regularization parameter for trade off between the accuracy and stability of approximate *** new method is based on a combination of the boundary condition and the boundary measurement in a parameter-dependent single complex Robin boundary condition,followed by the Tikhonov *** properly adjusting the parameter in the Robin boundary condition,we achieve two important properties for our new method:first,the regularized solutions are uniformly stable with respect to the regularization parameter so that the regularization parameter can be chosen based solely on the consideration of the solution accuracy;second,the convergence order of the regularized solutions reaches one with respect to the noise ***,the finite element method is used to compute numerical solutions and a newfinite element error estimate is derived for discrete *** results improve related results found in the existing *** numerical examples are provided to illustrate the theoretical results.

关键词： Bioluminescence tomography Tikhonov regularization convergence rate finite element methods error estimate

On the Residual Finiteness of a Class of Infinite Soluble Groups

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Algebra Colloquium 2023年第1期30卷 155-164页

作者： Jun Liao Heguo Liu xiaoliang Luo Xingzhong Xu School of Mathematics and Statistics Hubei UniversityWuhan 430062China Department of Mathematics Hainan UniversityHaikou 570228China Department of Mathematics Taiyuan Normal University JinzhongShanxi 031609China

Let A be a completely decomposable homogeneous torsion-free abelian group of rank n(n≥2).Let m(n)=A×(a)be the split extension of A by an automorphismαwhich is a cyclic permutation of the direct components twisted b... 详细信息

关键词： residual finiteness infinite soluble group nilpotent group polycyclic group

Achieving Energy-Saving,Continuous Redox Flow Desalination with Iron Chelate Redoxmers

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Energy Material Advances 2023年第1期4卷 25-33页

作者： Rongxuan Xie Diqing Yue Zhenmeng Peng xiaoliang Wei Department of Chemical BiomolecularCorrosion EngineeringThe University of AkronAkronOH 44325USA Indiana University-Purdue University Indianapolis 723 West Michigan StreetIndianapolisIN 46202USA Purdue University 585 Purdue MallWest LafayetteIN 47907USA

Desalination of saline water is becoming an increasingly critical strategy to overcome the global challenge of drinkable water shortage,but current desalination methods are often plagued with major drawbacks of high energy consumption,high capital cost,or low desalination *** address these drawbacks,we have developed a unique continuous-mode redox flow desalination approach capitalizing on the characteristics of redox flow *** operation is based on shuttled redox cycles of very dilute Fe^(2+)/Fe^(3+)chelate redoxmers with ultralow cell *** air instability of Fe^(2+)chelate is naturally compensated for by its in situ electrochemical generation,making the desalination system capable of operations with electrolytes at any specified state of *** unoptimized conditions,fast desalination rates up to 404.4 mmol·m^(−2)·h^(−1) and specific energy consumptions as low as 7.9 Wh·molNaCl^(−1) have been successfully ***,this desalination method has offered an opportunity of sustainable,distributed drinkable water supplies through direct integration with renewable energy sources such as solar ***,our redox flow desalination design has demonstrated competitive desalination performance,promising to provide an energy-saving,high-capacity,robust,cost-effective desalination solution.

关键词： solution. chelate dilute

Molecular dynamics simulation of effects of nanoparticles on frictional heating and tribological properties at various temperatures

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Friction 2020年第3期8卷 531-541页

作者： Chengzhi HU Jizu LV Minli BAI xiaoliang ZHANG Dawei TANG Laboratory of Ocean Energy Utilization of Ministry of Education School of Energy and Power EngineeringDalian University of TechnologyDalian 116024China

The temperature of a friction pair exerts considerable influence on the tribological behavior of a *** two cases,one with and the other without Cu(copper)nanoparticles,the temperature increase in friction pairs caused by frictional heating and its tribological properties at various temperatures are studied by using the molecular dynamics *** results show that temperature distribution and surface abrasion are significantly improved by the presence of Cu *** is one of the reasons for the improvements in tribological properties achieved in the presence of *** temperature and range of influence of frictional heating for the model without nanoparticles are significantly increased with the increase in the sliding velocity;however,in the model with nanoparticles,the temperature gradient is confined to the area near the Cu *** an increase in the temperature of the friction pair,the improvement in anti-wear properties associated with the presence of Cu nanoparticles becomes more significant.

关键词： nanoparticles molecular dynamics temperature tribological properties

Optimized Relinearization Algorithm of the Multikey Homomorphic Encryption Scheme

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Tsinghua Science and Technology 2022年第3期27卷 642-652页

作者： Xiaoyuan Yang Shangwen Zheng Tanping Zhou Yao Liu xiaoliang Che College of Cryptographic Engineering Engineering University of PAPXi’an 710086China

Multikey homomorphic encryption(MKHE) supports arbitrary homomorphic evaluation on the ciphertext of different users and thus can be applied to scenarios involving multiusers(e.g., cloud computing and artificial intelligence) to protect user privacy. CDKS19 is the current most efficient MKHE scheme, and its relinearization process consumes most of the time of homomorphic evaluation. In this study, an optimized relinearization algorithm of CDKS19 is proposed. This algorithm reorganizes the evaluation key during the key generation process, decreases the complexity of relinearization, and reduces the error growth rate during homomorphic evaluation. First, we reduce the scale of the evaluation key by increasing its modulus instead of using a gadget vector to decompose the user’s public key and extend the ciphertext of homomorphic multiplication. Second, we use rescaling technology to optimize the relinearization algorithm;thus, the error bound of the ciphertext is reduced, and the homomorphic operation efficiency is improved. Lastly, the average-case error estimation on the variances of polynomial coefficients and the upper bound of the canonical embedding map are provided. Results show that our scheme reduces the scale of the evaluation key, the error variance, and the computational cost of the relinearization process. Our scheme can effectively perform the homomorphic multiplication of ciphertexts.

关键词： multikey homomorphic encryption relinearization evaluation key rescaling

Design and application of an air-cooled probe for total pressure measurement at combustor outlet

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航空动力学报 2019年第1期34卷 34-44页

作者： LIU Xupeng SUN Qi WANG xiaoliang XUE Xiusheng YIN Dong Shenyang Engine Research Institute Aero Engine Corporation of China

An air-cooled probe was designed for measurement of total pressure at combustor outlet;its cooling scheme combined the film cooling and convection *** the aid of CFD technique,cooling effectiveness of the coolant jets at various blow ratios was compared;suitable blow ratios and configuration of film holes were chosen *** overall cooling performance of the probe was evaluated via CFD technique,the design was improved according to the simulation result,and the cooling effect of the leading edge was obviously strengthened by increasing the local coolant mass flow *** results of wind tunnel test indicated that,between Mach numbers 0.2 and 0.4,the probe achieved a high accuracy at various attack *** probe was utilized in an annular combustor rig test,the highest temperature reached 1 760 Kand total pressure reaches 1 036 *** result of rig test demonstrates that the coolant film distribution consistent appropriately with the CFD results.

关键词： high temperature measurement total pressure probe film cooling CFD combustor outlet

Enhancement of the efficiency of PEI/liposome transfection by magnetofectins formed via electrostatic self-assembly

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Chinese Science Bulletin 2012年第31期57卷 4005-4011页

作者： MA YongJie WANG xiaoliang GU HongChen Nano Biomedical Research Center School of Biomedical EngineeringShanghai Jiao Tong UniversityShanghai 200030China

One of the major challenges for successful gene therapy is improving the transfection efficiency of non-viral vectors. Magnetic nanoparticles (MNPs) have been developed as enhancers of non-viral vehicles. We prepared MNPs and modified them with polyethyleneimine (PEI), citric acid (CA) or carboxylmethyl-dextran (CMD). Both positively charged MNPs (MNPs@PEI) and negatively charged MNPs (MNPs@CA, MNPs@CMD) could spontaneously form transfection complexes (magnetofectins) with plasmid DNA and PEI/liposome via electrostatic self-assembly. Our results showed as-prepared magnetofectins apparently enhanced PEI/liposome transfection efficiency and/or gene expression level into COS-7 cells with reduced transfection time from 4 h to 15 min under a magnetic field in vitro. Meanwhile, the effect of magnetofection was cell line-dependant. These results suggest that charged MNPs could improve transfection efficiency for non-viral vectors by simply mixing with them and by exerting a magnetic force. Thus such MNPs provide a convenient platform for further applications of gene delivery.

关键词：脂质体转染静电自组装 PEI 效率增强 COS-7细胞非病毒载体转染效率磁性纳米粒子