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Compressed Least Squares Algorithm of Continuous-Time Linear Stochastic regression Model Using Sampling Data

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Journal of Systems Science & Complexity 2024年第4期37卷 1488-1506页

作者： XIe Siyu ZHANG Shujun WANG Ziming GAN die School of Aeronautics and Astronautics University of Electronic Science and Technology of ChinaChengdu 611731China China Academy of Aerospace Science and Innovation Beijing 100176China Zhongguancun Laboratory Beijing 100094China

In this paper,the authors consider a sparse parameter estimation problem in continuoustime linear stochastic regression models using sampling *** on the compressed sensing(CS)method,the authors propose a compressed least squares(LS) algorithm to deal with the challenges of parameter *** each sampling time instant,the proposed compressed LS algorithm first compresses the original high-dimensional regressor using a sensing matrix and obtains a low-dimensional LS estimate for the compressed unknown ***,the original high-dimensional sparse unknown parameter is recovered by a reconstruction *** introducing a compressed excitation assumption and employing stochastic Lyapunov function and martingale estimate methods,the authors establish the performance analysis of the compressed LS algorithm under the condition on the sampling time interval without using independence or stationarity conditions on the system *** last,a simulation example is provided to verify the theoretical results by comparing the standard and the compressed LS algorithms for estimating a high-dimensional sparse unknown parameter.

关键词： Compressed excitation condition compressed sensing continuous-time model least squares linear stochastic regression parameter identification sampling data

Stability and performance analysis of the compressed Kalman filter algorithm for sparse stochastic systems

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Science China(Technological Sciences) 2024年第2期67卷 380-394页

作者： LI rongJiang GAN die XIe SiYu LüJinHu Key Laboratory of Systems and Control Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China Zhongguancun Laboratory Beijing 100049China School of Aeronautics and Astronautics University of Electronic Science and Technology of ChinaChengdu 611731China School of Automation Science and electrical engineering Beihang UniversityBeijing 100191China

This paper considers the problem of estimating unknown sparse time-varying signals for stochastic dynamic *** deal with the challenges of extensive sparsity,we resort to the compressed sensing method and propose a compressed Kalman filter(KF)*** algorithm first compresses the original high-dimensional sparse regression vector via the sensing matrix and then obtains a KF estimate in the compressed low-dimensional ***,the original high-dimensional sparse signals can be well recovered by a reconstruction *** ensure stability and establish upper bounds on the estimation errors,we introduce a compressed excitation condition without imposing independence or stationarity on the system signal,and therefore suitable for feedback *** further present the performance of the compressed KF ***,we show that the mean square compressed tracking error matrix can be approximately calculated by a linear deterministic difference matrix equation,which can be readily evaluated,analyzed,and ***,a numerical example demonstrates that our algorithm outperforms the standard uncompressed KF algorithm and other compressed algorithms for estimating high-dimensional sparse signals.

关键词： sparse signal compressed sensing Kalman filter algorithm compressed excitation condition stochastic stability tracking performance

How mutual funds respond to asymmetric feedback tradingin China’s stock market

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Journal of Management Science and engineering 2024年第2期9卷 143-160页

作者： die Wan Li Yang Xiaoguang Yang School of Finance Zhejiang Gongshang UniversityHangzhou310018China Business School University of New South WalesSydneyAustralia Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijingChina

Previous studies show that individual investors play a dominant role in China's stock *** behavior of chasing-rise being stronger than killing-fall leads to asymmetry of feedback *** article investigates how mutual funds react to this market *** China's stock and fund data from 2003 to 2019,we find that mutual funds tend to hold fewer shares when asymmetric feedback trading of the relevant stock gets more *** negative relationship is robust after controlling past returns,turnover rates,and firm risk factors,moreover,it attenuates when the market sentiment is bullish or when stocks are allowed *** results show that mutual funds'selling towards asymmetric feedback trading does not make excess return but leads to significant risk *** findings may be related to uncertainty associated with asymmetric feedback trading,and thus support the limit market participation theory from the second largest stock market.

关键词： Asymmetric feedback trading Mutual fund shareholdings Uncertainty Market sentiment Short selling

Formation behaviors of rod-like reactive shaped charge penetrator and their effects on damage capability

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Defence Technology（防务技术） 2024年第2期32卷 242-253页

作者： Tao Sun Haifu Wang Shipeng Wang Chao Ge die Hu Pengwan Chen Yuanfeng Zheng Beijing Institute of Technology State Key Laboratory of Explosion Science and TechnologyBeijing100081China Xi'an Institute of electromechanical Information Technology Xi'an710065China

Formation behaviors of rod-like reactive shaped charge penetrator(rrSCP)and their effects on damage capability are investigated by experiments and numerical *** pulsed X-ray technology and a spaced aluminum/steel plate with the thicknesses of 5 mm/100 mm are *** types of sphericalsegment aluminum-polytetrafluoroethylene-copper(Al-PTFe-Cu)reactive liners with Cu contents of 0%,46.6%,and 66%are fabricated and *** experimental results show that the reactive liners can form excellent rod-shaped penetrators with tail skirts under the shaped charge effect,but the tail skirts disappear over ***,rupturing damage to the aluminum plate and penetration to the steel plate are caused by the rrSCP *** simulation analysis,the rrSCP is formed by a mechanically and chemically coupled response with the reactive liner activated by shock in its outer walls and bottom and then backward overturning,forming a leading reactive penetrator and a following chemical energy *** unique formation structure determines the damage modes of the aluminum plate and the steel *** analysis indicates that the formation behaviors and damage capability of Al-PTFe-Cu rrSCP strongly depend on Cu *** increasing Cu content,the velocity,activation extent,and reaction extent of Al-PTFe-Cu rrSCP decrease,which contribute to elongation and alleviate the negative effects of chemical reactions on elongation,significantly increasing the length-diameter ratio and thus enhancing the capability of steel plate ***,the lower activation extent and energetic density will weaken the rrSCP's capability of causing rupturing damage to the aluminum plate.

关键词： reactive materials Al-PTFe composites reactive liner X-ray Penetration

Cucurbit[8]uril-regulated face-to-face dimerization assembly enhanced photosensitization and photocatalysis

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Science China Chemistry 2024年第5期67卷 1605-1612页

作者： Haigen Nie die Hu Zhiyao Zeng Yan Fan Yaxin Zhai Xin-Long Ni Key Laboratory of Chemical Biology and Traditional Chinese Medicine Ministry of Educational of ChinaKey Laboratory of the Assembly and Application of Organic Functional Molecules of Hunan ProvinceCollege of Chemistry and Chemical EngineeringHunan Normal UniversityChangsha 410081China Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of education Department of PhysicsHunan Normal UniversityChangsha 410081China

In water, N,N′-diarylpyridinium thiazolo[5,4-d]thiazole guests(G1–G3) were encapsulated by cucurbit[8]uril(Q[8]) to construct Q[8]_(3)/G_(2) complexes, in which the encapsulated G molecules exist as an exact face-to-face dimer. These complexation behaviors have been indicated by proton nuclear magnetic resonance(~1H NMr) spectroscopy and isothermal titration calorimetry(ITC),and have been confirmed by X-ray single crystal structural analysis of Q[8]_(3)/G2_(2). While free guests G1–G3 have no ability to sensitize singlet oxygen, they all become effective singlet oxygen sensitizers when complexed with Q[8]. By irradiation of white light, Q[8]_(3)/G_(2) complexes induced selective oxidation of aryl sulfide to aryl sulfoxide in good yields and selective oxidation of dimethyl sulfide(DMS) to dimethyl sulfoxide(DMSO) in excellent yields without over-oxidation to dimethyl sulfone(DMSO_(2))even for elongated irradiation. High-yield photo-oxidation of DMS to DMSO_(2) was only achieved by irradiation of blue light in the presence of Q[8]_(3)/G1_(2), which was also effective in photobleaching of rhodamine B in water. The higher photo-oxidation power of Q[8]_(3)/G1_(2) has been ascribed to an additional generation of reactive oxygen species besides singlet oxygen.

关键词： host-guest interaction dimerization macrocycles photosensitization

Nanoparticle delivery for central nervous system diseases and its clinical application

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Nano research 2024年第7期17卷 6305-6322页

作者： Lin Tang rui Zhang Yusi Wang Mohan Liu die Hu Yuanda Wang Li Yang Department of Biotherapy Cancer Center and State Key Laboratory of BiotherapyWest China HospitalSichuan UniversityChengdu 610041China

In the treatment of central nervous system(CNS)diseases such as glioma,Alzheimer's disease(AD)and Parkinson's disease(PD),drugs are expected to reach specific areas of the brain to achieve the desired *** a growing number of therapeutic targets have been identified in preclinical studies,the ones that can ultimately be used in the clinic are ***,the research process and clinical application of drugs for treating CNS diseases are still large *** barriers such as the blood‒brain barrier(BBB)act as selective permeable membranes,allowing only certain molecules to enter the brain;this barrier is the major obstacle restricting the arrival of most drugs to brain ***,nanoparticles,including lipid-based,cell-derived biomimetic,polymeric and inorganic nanoparticles,have gained increasing attention because of their ability to cross physiological barriers,and could play an important role as delivery carriers and ***,clinical applications of nanoparticles in CNS diseases are *** review focuses on the progress of current research on the use of nanoparticles for the treatment of CNS diseases to provide additional insight into the treatment of CNS diseases.

关键词： nanoparticles central nervous system(CNS)diseases clinical applications delivery carriers immunomodulators

Magnetic Co-doped 1D/2D structuredγ-Fe_(2)O_(3)/MoS_(2) effectively activated peroxymonosulfate for efficient abatement of bisphenol A via both radical and non-radical pathways

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Frontiers of environmental Science & engineering 2024年第3期18卷 143-159页

作者： Junge Xu Dong Wang die Hu Ziwei Zhang Junhong Chen Yingmu Wang Yifeng Zhang College of Civil engineering Fuzhou UniversityFuzhou 350116China China Nuclear Power engineering Co. Ltd.Shenzhen 518120China Department of environmental&resource engineering Technical University of DenmarkLyngby DK-2800Denmark

Iron-based catalysts have been widely used to treat refractory organic pollutants in *** this paper,magnetic Co-γ-Fe_(2)O_(3)was synthesized by a facile tartaric acid-assisted hydrothermal method,and Co-γ-Fe_(2)O_(3)/MoS_(2) nanocomposite catalyst was obtained via in situ growth of MoS_(2) nanosheets on Co-γ-Fe_(2)O_(3)*** nanocomposite catalysts were used to decompose bisphenol A(BPA)by activating peroxymonosulfate(PMS).It was shown that only 0.15 g/L catalyst and 0.5 mmol/L PMS degraded 10 mg/L of BPA(99.3%within 10 min)in the pH range of 3–*** was activated due to redox cycling among the pairs Co(III)/Co(II),Fe(III)/Fe(II),and Mo(VI)/Mo(IV).Quenching experiments and electron paramagnetic resonance spectroscopy demonstrated that both radical and non-radical pathways were involved in BPA degradation,in which active radical sulfate radical and non-radical singlet oxygen were the main reactive oxygen *** intermediates were identified by liquid chromatography-coupled mass spectrometry,and three possible BPA degradation pathways were *** toxicity of several degradation intermediates was lower,and Co-γ-Fe_(2)O_(3)/MoS_(2) exhibited excellent reusability and could be magnetically recovered.

关键词： Magnetic Co-γ-Fe_(2)O_(3) /MoS_(2) Hydrothermal method Bisphenol A Degradation pathways Toxicity analysis

Prediction of solar activities:Sunspot numbers and solar magnetic synoptic maps

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Science China earth Sciences 2024年第8期67卷 2460-2477页

作者： rui ZHUO Jiansen He die DUAN rong LIN Ziqi WU Limei YAN Yong WeI School of earth and Space Sciences Peking UniversityBeijing 100091China College of Advanced Interdisciplinary Studies National University of Defense TechnologyChangsha 410073China Centre for Mathematical Plasma Astrophysics Department of MathematicsKU LeuvenLeuven 3001Belgium Key Laboratory of earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

The evolution of solar magnetic fields is significant for understanding and predicting solar *** our knowledge of solar magnetic fields largely depends on the photospheric magnetic *** this paper,based on the spherical harmonic expansion of the photospheric magnetic field observed by Wilcox Solar Observatory,we analyze the time series of spherical harmonic coefficients and predict Sunspot Number as well as synoptic maps for Solar Cycle *** find that solar maximum years have complex short-period disturbances,and the time series of coefficient g_(7)~0 is nearly in-phase with Sunspot Number,which may be related to solar meridional *** Long Short-Term Memory networks(LSTM),our prediction suggests that the maximum of Solar Cycle 25 is likely to occur in June 2024 with an error of 8 months,the peak sunspot number may be 166.9±22.6,and the next solar minimum may occur around January *** incorporating empirical Mode Decomposition,we enhance our forecast of synoptic maps truncated to Order 5,validating their relative *** prediction not only addresses a gap in forecasting the global distribution of the solar magnetic field but also holds potential reference value for forthcoming solar observation plans.

关键词： Solar activity prediction Solar magnetic field Spherical harmonic expansion Long-Short Term Memory(LSTM) empirical Mode Decomposition(eMD)

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response of soil nutrients to terracing and environmental factors in the Loess Plateau of China

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Geography and Sustainability 2024年第2期5卷 230-240页

作者： die Chen Wei Wei Liding Chen Bojun Ma Hao Li Department of Soil and Water Conservation Changjiang River Scientific Research InstituteWuhan 430010China State Key Laboratory of Urban and regional ecology Research Center for Eco-environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China research Center on Mountain Torrent&Geologic Disaster Prevention of Ministry of Water resources Wuhan 430010China

Terracing is a widely adopted agricultural practice in mountainous regions around the world that aims to conserve soil and water *** nutrients play a crucial role in determining soil quality,particularly in landscapes prone to *** are influenced by factors such as land-use type,slope aspect,and *** this study,we sought to examine the impact of terracing on soil nutrients(soil organic content(SOC),total nitrogen(TN),nitrate-nitrogen(NO3–-N),ammonium nitrogen(NH4+-N),total phosphorus(TP),available phosphorus(AP),total potassium(TK),and available potassium(AK))and how they vary with environmental factors in the Chinese Loess *** the growing season,we collected 540 soil samples from the 0 to 100 cm soil layer across five major land-use types,different slope aspects,and varying ***,a meta-analysis of literature data further corroborated the effective accumulation of soil nutrients through terracing in the Loess *** findings are as follows:(1)Terraced fields,regardless of land-use type,showed a significant improvement in SOC and TN content.(2)Soil nutrient contents within terraced fields were predominantly higher on sunny slopes.(3)Terraces at lower altitudes are characterized by elevated SOC concentrations.(4)A meta-analysis of literature data pertaining to terracing and soil nutrients in this region confirmed the effective accumulation of soil nutri-ents through *** elucidated outcomes of this study offer a profound theoretical underpinning for the accurate planning and management of terraces,the scientific utilization of land resources,and the enhancement of land productivity.

关键词： Terrace Soil nutrients Land-use Slope aspect Altitude Loess Plateau