检索结果-南通市图书馆

A multipath mitigation algorithm for GNSS signals based on the steepest descent approach

在线全文

学校读者我要写书评

暂无评论

Satellite Navigation 2022年第3期3卷 80-90,I0003页

作者： Wenqi Qiu qinghua zeng Rui Xu Jianye Liu Jinheng Shi Qian Meng Navigation Research Center College of Automation EngineeringNanjing University of Aeronautics and AstronauticsNanjing211106China Key Laboratory of the MIIT Advanced Aircraft Navigation Control and Health ManagementNanjing211106China Jiangsu University Collaborative Innovation Center for Satellite Communication and Navigation Nanjing211106China School of Instrument Science and Engineering Southeast UniversityNanjing211106China

Multipath interference seriously degrades the performance of Global Navigation Satellite System(GNSS)positioning in an urban canyon.Most current multipath mitigation algorithms suffer from heavy computational load or need external assistance.We propose a multipath mitigation algorithm based on the steepest descent approach,which has the merits of less computational load and no need for external aid.A new ranging code tracking loop is designed based on the steepest descent method,which can save an early branch or a late branch compared with the narrow-spacing correlation method.The power of the Non-Line-of-Sight(NLOS)signal is weaker than that of the Line-of-Sight(LOS)signal when the LOS signal is not obstructed and with a relatively high Carrier Noise Ratio(CNR).The peak position in the X-axis of the ranging code autocorrelation function does not move with the NLOS interference.Meanwhile,the cost function is designed according to this phenomenon.The results demonstrate that the proposed algorithm outperforms the narrow-spacing correlation and the Multipath Estimated Delay Locked Loop(MEDLL)in terms of the code multipath mitigation and computation time.The Standard Deviation(STD)of the tracking error with the proposed algorithm is less than 0.016 chips.Moreover,the computation time of the proposed algorithm in a software defined receiver is shortened by 24.21%compared with the narrow-spacing correlation.

关键词： Code multipath mitigation Steepest descent GNSS Narrow-spacing correlation BDS

Estrogen deficiency exacerbates learning and memory deficits associated with glucose metabolism disorder in APP/PS1 double transgenic female mice

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Genes & Diseases 2022年第5期9卷 1315-1331页

作者： Min Luo qinghua zeng Kai Jiang Yueyang Zhao Zhimin Long Yexiang Du Kejian Wang Guiqiong He Chongqing Key Laboratory of Neurobiology Chongqing Medical UniversityChongqing 400016PR China Department of Pathology Suining Municipal Hospital of TCMSuiningSichuan 629000PR China Department of Anatomy Chongqing Medical UniversityChongqing 400016PR China Department of Gastroenterology Suining Central HospitalSuiningSichuan 629000PR China

Alterations in glucose metabolism occur in the brain in the early stage of Alzheimer's disease(AD),and menopausal women have more severe metabolic dysfunction and are more prone to dementia than men.Although estrogen deficiency-induced changes in glucose metabolism have been previously studied in animal models,their molecular mechanisms in AD remain elusive.To investigate this issue,double transgenic(APP/PS1)female mice were subjected to bilateral ovariectomy at 3 months of age and were sacrificed 1 week,1 month and 3 months after surgery to simulate early,middle and late postmenopause,respectively.Our analysis demonstrated that estrogen deficiency exacerbates learning and memory deficits in this mouse model of postmenopause.Estrogen deficiency impairs the function of mitochondria in glucose metabolism.It is possible that the occurrence of AD is associated with the aberrant mitochondrial ERβ-mediated IGF-1/IGF-1R/GSK-3βsignaling pathway.In this study,we established a potential mechanism for the increased risk of AD in postmenopausal women and proposed a therapeutic target for AD due to postmenopause.

关键词： Alzheimer’s disease Estrogen deficiency Glucose metabolism disorder GSK-3b IGF-1 Mitochondria

Obese Ningxiang pig-derived microbiota rewires carnitine metabolism to promote muscle fatty acid deposition in lean DLY pigs

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The Innovation 2023年第5期4卷 69-77页

作者： Jie Yin Yunxia Li Yu Tian Feng Zhou Jie Ma Siting Xia Tong Yang Libao Ma qinghua zeng Gang Liu Yulong Yin Xingguo Huang College of Animal Science and Technology Hunan Agriculture UniversityChangsha 410128China College of Animal Sciences and Technology Huazhong Agricultural UniversityWuhan 430070China Hunan Chuweixiang Agriculture and Animal Husbandry Co LtdNingxiang 410600China Instiute of Subtropical Agriculture Chinese Academy of SciencesChangsha 410125China

The gut microbiota consistently shows strong correlations with lipid metabolism in humans and animals,and whether the gut microbiota contributes to muscle fatty acid(FA)deposition and meat traits in farm animals has not been fully resolved.In this study,we aimed to unveil the microbial mechanisms underlying muscle FA deposition in pigs.First,we systematically revealed the correlation between the gut microbiome and muscle FA levels in 43 obese Ningxiang pigs and 50 lean Duroc Landrace Yorkshire(DLY)pigs.Mutual fecal microbial transplantation showed that the obese Ningxiang pig-derived microbiota increased the muscle FA content and improved meat quality by reshaping the gut microbial composition in lean DLY pigs.Lactobacillus reuteri has been identified as a potential microbial biomarker in obese Ningxiang pig-derived microbiota-challenged DLY pigs.A gavage experiment using lean DLY pigs confirmed that L.reuteri XL0930 isolated from obese Ningxiang pigs was the causal species that increased the muscle FA content.Mechanistically,SLC22A5,a carnitine transporter,was downregulated in L.reuteri XL0930-fed DLY pigs,resulting in reduced muscle carnitine levels.Muscle and intestinal L-carnitine levels,which correlated with the muscle FA content,impeded fat synthesis and FA accumulation in in vitro and in vivo models.In conclusion,we uncovered an unexpected and important role of the obese Ningxiang pig-derived microbiota in regulating muscle FA metabolism via the SLC22A5-mediated carnitine system.

关键词： DLY Ningxia fir

Efficient Semi‑Transparent Wide‑Bandgap Perovskite Solar Cells Enabled by Pure‑Chloride 2D‑Perovskite Passivation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano-Micro Letters 2023年第8期15卷 35-48页

作者： Liu Yang Yongbin Jin Zheng Fang Jinyan Zhang Ziang Nan Lingfang Zheng Huihu Zhuang qinghua zeng Kaikai Liu Bingru Deng Huiping Feng Yujie Luo Chengbo Tian Changcai Cui Liqiang Xie Xipeng Xu Zhanhua Wei Xiamen Key Laboratory of Optoelectronic Materials and Advanced Manufacturing Institute of Luminescent Materials and Information DisplaysCollege of Materials Science and EngineeringHuaqiao UniversityXiamen 361021People’s Republic of China MOE Engineering Research Center for Brittle Materials Machining Institute of Manufacturing EngineeringCollege of Mechanical Engineering and AutomationHuaqiao UniversityXiamen 361021People’s Republic of China Gold Stone(Fujian)Energy Company Limited Quanzhou 362005People’s Republic of China Collaborative Innovation Center of Chemistry for Energy Materials Department of ChemistryCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005People’s Republic of China

Wide-bandgap(WBG)perovskite solar cells suffer from severe non-radiative recombination and exhibit relatively large opencircuit voltage(V_(OC))deficits,limiting their photovoltaic performance.Here,we address these issues by in-situ forming a well-defined 2D perovskite(PMA)_(2)PbCl_(4)(phenmethylammonium is referred to as PMA)passivation layer on top of the WBG active layer.The 2D layer with highly pure dimensionality and halide components is realized by intentionally tailoring the side-chain substituent at the aryl ring of the post-treatment reagent.First-principle calculation and single-crystal X-ray diffraction results reveal that weak intermolecular interactions between bulky PMA cations and relatively low cation-halide hydrogen bonding strength are crucial in forming the well-defined 2D phase.The(PMA)_(2)PbCl_(4)forms improved type-I energy level alignment with the WBG perovskite,reducing the electron recombination at the perovskite/hole-transport-layer interface.Applying this strategy in fabricating semi-transparent WBG perovskite solar cells(indium tin oxide as the back electrode),the V_(OC)deficits can be reduced to 0.49 V,comparable with the reported state-of-the-art WBG perovskite solar cells using metal electrodes.Consequently,we obtain hysteresis-free 18.60%-efficient WBG perovskite solar cells with a high V_(OC)of 1.23 V.

关键词： Wide-bandgap perovskite solar cells Transparent back electrodes Defect passivation Bulky cations

Impact of one satellite outage on ARAIM depleted constellation configurations

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2019年第4期32卷 967-977页

作者： Qian MENG Jianye LIU qinghua zeng Shaojun FENG Rui XU Navigation Research Center Nanjing University of Aeronautics and Astronautics Centre for Transport Studies Imperial College London

Advanced Receiver Autonomous Integrity Monitoring(ARAIM) is a new technology that will provide worldwide coverage of vertical guidance in aviation navigation. The ARAIM performance and improvement under depleted constellations is a practical problem that needs to be faced and researched further. It is a shortcut that improves the availability in position domain whose key idea is to replace the conventional least squares process with a non-least-squares estimator to lower the integrity risk in exchange for a slight increase in nominal position error. The contributions given in this paper include two parts: First, the impacts of one satellite outage on different constellations are analyzed and compared. The conclusion is that GPS is more sensitive and vulnerable to one satellite outage. Second, a constellation weighted ARAIM(CW-ARAIM)position estimator is proposed. The position solution is replaced by a constellation weighted average solution to eliminate the constellation difference. The new solution will move close to the constellation solutions with respect to the accuracy requirement. The simulation results under baseline GPS and Galileo dual-constellation show that the one GPS satellite outage will knock the availability from 91% to only 50%. The performance remains stable with one Galileo satellite outage. With the assistance of the CW-ARAIM method, the availability can increase from 50% to more than80% under depleted GPS configurations. Even without any satellite outage, the proposed method can effectively improve the availability from 91.29% to 98.75%. The test results under optimistic constellations further verify that a balanced constellation is more important than more satellites on orbit and the superiority of CW-ARAIM method is still effective.

关键词： Advanced receiver autonomous integrity monitoring Depleted constellation One satellite outage Position estimator Weighted solution

Molecular dynamics simulation of aluminum inhibited leaching during ion-adsorbed type rare earth ore leaching process

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2019年第12期37卷 1334-1340页

作者： Dongmei Zhu Tingsheng Qiu Jianfeng Zhong qinghua zeng Xihui Fang School of Resource and Environmental Engineering Jiangxi University of Science and TechnologyGanzhou 341000China School of Computing Engineering and MathematicsUniversity of Western SydneyPenrith NSW 2751Australia

Molecular dynamics simulation was adopted to study the interaction between sulfosalicylic acid and aluminum,lanthanum and yttrium,and adsorption on kaolinite surfaces.A complexation reaction occurs between sulfosalicylic acid and aluminum,with an interaction energy of-10472.05 kJ/mol.O—Al covalent bonds are formed with a peak value of 7.93,while there is only weak adsorption between sulfosalicylic acid and rare earth ions.A hydrogen bonding reaction with 13605.82 kJ/mol energy occurs between sulfosalicylic acid and the surface of kaolinite(100).Thus,sulfosalicylic acid can form a complex with free aluminum ions,and can also be adsorbed on kaolinite by hydrogen bonding with aluminum in kaolinite(100)surfaces.Leaching of ion-adsorbed type rare earth ore was performed with aluminum inhibited,results show that when sulfosalicylic acid dosage increases from 0 to 0.15 wt%,aluminum ion concentration in the leaching solution decreases from 273.23 to 47.19 mg/L.And the effect of leaching pH value on the effect of sulfosalicylic acid on aluminum inhibition was studied,the result shows that,when the leaching pH value is 4.0—5.0,the rare earth leaching rate and the aluminum ion concentration basically remain unchanged.The molecular dynamics simulation results were verified by detection and analysis of XPS and SEM.

关键词： Ion-adsorbed type rare earth ore Molecular dynamics simulation Sulfosalicylic acid Aluminum ions Aluminum inhibited leaching

基于交互式多模型因子图的自适应组合导航算法

在线全文

学校读者我要写书评

暂无评论

中国惯性技术学报 2024年第4期32卷 346-353页

作者：曾庆化王守一李方东邵晨南京航空航天大学自动化学院南京210016

针对复杂城市环境下因外部干扰或传感器故障而引起的传统车载导航系统定位精度下降的问题,提出了一种基于因子图的交互式多模型车载导航算法。基于因子图优化算法建立了IMU/GNSS/LIDAR组合导航系统模型,引入了交互式多模型对子系统传感... 详细信息

针对复杂城市环境下因外部干扰或传感器故障而引起的传统车载导航系统定位精度下降的问题,提出了一种基于因子图的交互式多模型车载导航算法。基于因子图优化算法建立了IMU/GNSS/LIDAR组合导航系统模型,引入了交互式多模型对子系统传感器量测进行建模并构建变量节点,利用模型概率更新来优化传感器权重,并依据因子图非线性优化和增量平滑理论实现车载导航系统的解算与更新。实验结果表明:相比于自适应因子图算法,所提算法在复杂城市环境下的定位精度提高了26.2%。

关键词：因子图交互式多模型车载导航复杂场景

A high dynamics algorithm based on steepest ascent method for GNSS receiver

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2021年第12期34卷 177-186页

作者： qinghua zeng Wenqi QIU Jianye LIU Rui XU Jinheng SHI Yongrong SUN Navigation Research Center Nanjing University of Aeronautics&AstronauticsNanjing 211106China Key Laboratory of the MI IT Advanced Aircraft Navigation Control ami Health ManagementNanjing 211106China Jiangsu University Collaborative Innovation Center for Satellite Communication and Navigation Nanjing 211106China

High dynamic conditions impose critical challenges on Global Navigation Satellite System(GNSS)receivers,leading to large tracking errors or even loss of tracking.Current methods that intend to improve receivers’adaptability for high dynamics require either complicated structures or prior statistical information of noises.This paper proposes a high dynamics algorithm based on steepest ascent method that can circumvent the deficiencies of existing methods.First,the relationship between the error of carrier tracking and the maximum of Fast Fourier Transform(FFT)outputs is established,and a performance function based on the steepest ascent method is designed.It can keep stable in high dynamics.Second,a new carrier-tracking loop is constructed by deploying the performance function.When the variation of GPS receiver acceleration ranges from 10 g to 100 g,compared with the PLL that either loses lock or keeps tracking accuracy less than 33.89 Hz,the experimental results show that the proposed method can not only keep tracking,but also achieve tracking accuracy more than 2.77 Hz.

关键词： Carrier tracking loops Fast Fourier Transform(FFT) Global Navigation Satellite System(GNSS) High dynamics Steepest ascent

在线全文

学校读者我要写书评

暂无评论

考虑传函零点的光电稳定平台抗扰控制设计

红外与激光工程 2024年第5期53卷 133-142页

作者：翟方超曾庆化张越杰王合龙李杰南京航空航天大学自动化学院江苏南京2100162 中国航空工业集团公司洛阳电光设备研究所河南洛阳471000

针对当前光电稳定平台伺服系统中自抗扰控制设计方法未考虑系统零点的问题,文中提出一种考虑传函零点的光电稳定平台抗扰控制设计方法。该方法通过扰动设计的方法将有零点的传函转换为无零点传函,使用扰动分离状态观测设计技术对设计的... 详细信息

针对当前光电稳定平台伺服系统中自抗扰控制设计方法未考虑系统零点的问题,文中提出一种考虑传函零点的光电稳定平台抗扰控制设计方法。该方法通过扰动设计的方法将有零点的传函转换为无零点传函,使用扰动分离状态观测设计技术对设计的扰动进行补偿。仿真实验结果表明:在控制器相同、扰动条件相同的情况下,相比模型辅助的自抗扰算法,文中提出的算法阶跃响应调节时间减少80.72%,超调量减少61.97%;在1V2Hz等效扰动下,系统稳态精度提高36.69%,系统性能提升效果明显。在实物验证实验中,对于1V2Hz等效扰动下,文中提出的算法系统稳态精度提高了27.41%,对于不同频率的等效扰动,稳态精度能够提升20%以上,有效的提高了光电稳定平台的稳态精度。

关键词：光电稳定平台传函零点自抗扰控制