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Transition from Superparamagnetism to Ferromagnetic Single-Domain in a Heisenberg Model for Nano-cluster Magnetic System

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Chinese Physics Letters 2000年第5期17卷 367-369页

作者： shao yuan-zhi HE Zhen-Hui Department of Physics Zhongshan UniversityGuangzhou 510275

By considering a magnetic system of an ensemble of nanometer clusters without any external magnetic field,the Monte Carlo simulation of the Heisenberg model is used to investigate the transition from a superparamagnetism to a ferromagnetic single-domain state,which is caused by the growth of the *** studied the variation of the dynamic growth exponent P and the transition critical size of the cluster N_(c) against the reduced temperature t and the uniaxial anisotropy constant *** found that the growth exponent maximized at a certain temperature,other than being taken as a universal constant as some researchers suggested previously.

关键词： Heisenberg cluster exponent

The chemical treatments combined with antagonistic yeast control anthracnose and maintain the quality of postharvest mango fruit

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Journal of Integrative Agriculture 2019年第5期18卷 1159-1169页

作者： shao yuan-zhi ZENG Jiao-ke TANG Hong ZHOU Yi LI Wen College of Food Science Hainan University College of Horticulture Hainan University

During the storage and transportation of the mango fruit, the major source of disease is anthracnose, caused by the fungus Colletotrichum gloeosporioides. The objective of this study is to find an appropriate method that not only reduces mango decay but also maintains its postharvest quality. The effects of chemicals, the use of the yeast species Metschnikowia pulcherrima and their combination on storage quality, focusing on the enzyme activity related to disease of Tainong mangos was studied. By immersing the mangoes in M. pulcherrima suspension(1.0×10~8 cfu mL^(–1)), salicylic acid(SA) solution(50 mg L^(–1)) or calcium chloride(CaCl_2) solution(1.0 g L^(–1)), the lesion expansion and decay of the mango fruit caused by C. gloeosporioides could be significantly delayed. These treatments also delayed the changes in quality traits(a~* value, firmness, contents of total soluble solids(TSS) and vitamin C(Vc), while the activities of anti-disease enzymes such as polyphenol oxidase(PPO), phenylalanine ammonia lyase(PAL), chitinase(CHT) and β-1,3-glucanase(GUN) were enhanced as compared to the control treatment. Furthermore, the combination of SA solution, CaCl_2 solution and M. pulcherrima suspension presented an additive effect, increasing the efficacy in controlling the disease and maintaining the storage quality of mango fruits. Taken together, our data suggest that the integration of chemical treatments combined with M. pulcherrima could be an alternative to the use of fungicides in postharvest treatment of the mango fruit, specifically for improving storage quality as well as the control of the anthracnose.

关键词： mango fruit Metschnikowia pulcherrima Colletotrichum gloeosporioides storage quality enzyme activity

Synchronization in a Mutualism Ecosystem Induced by Noise Correlation

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Communications in Theoretical Physics 2008年第9期50卷 793-796页

作者： ZHONG Wei-Rong shao yuan-zhi BIE Meng-Jie HE Zhen-Hui School of Physics ＆ Engineering Sun Yat-sen University Guangzhou 510275 China Centre for Nonlinear Studies Hong Kong Baptist University Kowloon Tong Hong Kong China

Understanding the cause of the synchronization of population evolution is an important issue for *** we present a Lotka-Volterra-type model driven by two correlated environmental noises and show,via theoretical analysis and direct simulation,that noise correlation can induce a synchronization of the *** series of mutual species exhibit a chaotic-like fluctuation,which is independent of the noise correlation,however,the chaotic fluctuation of mutual species ratio decreases with the noise correlation.A quantitative parameter defined forcharacterizing chaotic fluctuation provides a good approach to measure when the complete synchronization happens.

关键词： environmental noise correlation synchronous fluctuation chaos population dynamics mutualism

Single-Step Fabrication of Gd_(2)O_(3)@SiO_(2) Nanoparticles for use as MRI Contrast Agents by Pulsed Laser Ablation in Liquid

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Chinese Physics Letters 2013年第3期30卷 183-185页

作者： LUO Ning-Qi HUANG Zhan-Yun LI Li shao yuan-zhi CHEN Di-Hu State Key Laboratory of Optoelectronic Materials and Technologies Sun Yat-sen UniversityGuangzhou 510275 State Key Laboratory of Oncology in Southern China Sun Yat-sen UniversityGuangzhou 510080

Gd_(2)O_(3)@SiO_(2) nanoparticles with a core-shell structure are synthesized by pulsed laser ablation in liquid(PLAL)in single steps.A Gd_(2)O_(3) target immersed in tetraethyl orthosilicate(TEOS)is ablated by a microsecond Nd:YAG laser,which induces the generation of a Gd_(2)O_(3) plasma plume and pyrolysis of the *** propose that the moment Gd_(2)O_(3) nanoparticles are formed they will be coated immediately by SiO_(2) and directly synthesized Gd_(2)O_(3)@SiO_(2) core-shell *** particles obtain high r1 relaxivity of 5.26 s^(-1)mM^(-1) and are used as T_(1)-weighted magnetic resonance imaging contrast *** is shown that the PLAL technique is promising for fabricating core-shell structure nanomaterial with potential medical applications.

关键词： Nd:YAG structure pyrolysis

Asymmetric alkenylation reaction of benzoxazinones with diarylethylenes catalyzed by B(C_(6)F_(5))_(3)/chiral phosphoric acid

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Chinese Chemical Letters 2024年第5期35卷 135-140页

作者： Zhen Liu zhi-yuan Ren Chen Yang Xiangyi shao Li Chen Xin Li State Key Laboratory of Elemento-Organic Chemistry Frontiers Science Center for New Organic MatterCollege of ChemistryNankai UniversityTianjin 300071China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China Zhenhai High School of Zhejiang Ningbo 315299China

Catalytic enantioselective alkenylation is an efficient method to construct chiral alkene molecules,but the asymmetric alkenylation of simple alkenes catalyzed by metal-free catalysts remains an elusive ***,we reported an asymmetric alkenylation of benzoxazinones with diarylethylenes by utilizing a B(C_(6)F_(5))_(3)/chiral phosphoric acid catalyst.A broad of benzoxazinones and diarylethylenes with electron-withdrawing and electron-donating groups were tolerated(up to 95%yield and 97.5:2.5 e.r.)in the methodology under mild reaction ***,the synthetic utility was confirmed by the scaled-up reaction and transformations of the *** mechanism was preliminarily explored by control reactions,nonlinear effect experiment and DFT calculations.

关键词： Asymmetric alkenylation Simple alkenes Benzoxazinones B(C_(6)F_(5))_(3)/chiral phosphoric acid Theoretical calculations

Synergic action of linear dispersion, second-order nonlinearity, and third-order nonlinearity in shaping the spectral profile of a femtosecond pulse transporting in a lithium niobate crystal

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Photonics Research 2024年第4期12卷 774-783页

作者： LIHONG HONG yuanyuan LIU zhi-yuan LI State Key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China

We present a detailed theoretical and numerical analysis on the temporal-spectral-spatial evolution of a highpeak-power femtosecond laser pulse in two sets of systems:a pure lithium niobate(LN)plate and a periodically poled lithium niobate(PPLN)*** develop a modified unidimensional pulse propagation model that considers all the prominent linear and nonlinear processes and carried out the simulation process based on an improved split-step Fourier transformation *** theoretically analyze the synergic action of the linear dispersion effect,the second-order nonlinearity(2nd-NL)second-harmonic generation(SHG)effect,and the third-order nonlinearity(3rd-NL)self-phase modulation(SPM)effect,and clarify the physical mechanism underlying the peculiar and diverse spectral broadening patterns previously reported in LN and PPLN thin plate *** analysis and discussion provides a deeper insight into the synergetic contribution of these linear and nonlinear effects brought about by the interaction of a femtosecond laser pulse with the LN nonlinear crystal and helps to draw a picture to fully understand these fruitful optical physical processes,phenomena,and laws.

关键词： pulse nonlinearity lithium

Integrated Clustering and Routing Design and Triangle Path Optimization for UAV-Assisted Wireless Sensor Networks

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China Communications 2024年第4期21卷 178-192页

作者： shao Liwei Qian Liping Wu Mengru Wu yuan College of Information Engineering Zhejiang University of TechnologyHangzhou 310014China State Key Laboratory of Internet of Things for Smart City University of MacaoMacaoChina Department of Computer and Information Science University of MacaoMacaoChina

With the development of the Internet of Things(IoT),it requires better performance from wireless sensor networks(WSNs),such as larger coverage,longer lifetime,and lower ***,a large amount of data generated from monitoring and long-distance transmission places a heavy burden on sensor nodes with the limited battery *** this,we investigate an unmanned aerial vehicles assisted mobile wireless sensor network(UAV-assisted WSN)to prolong the network lifetime in this ***,we use UAVs to assist the WSN in collecting *** the current UAV-assisted WSN,the clustering and routing schemes are determined ***,such a separate consideration might not maximize the lifetime of the whole WSN due to the mutual coupling of clustering and *** efficiently prolong the lifetime of the WSN,we propose an integrated clustering and routing scheme that jointly optimizes the clustering and routing *** the whole network space,it is intractable to efficiently obtain the optimal integrated clustering and routing ***,we propose the Monte-Las search strategy based on Monte Carlo and Las Vegas ideas,which can generate the chain matrix to guide the algorithm to find the solution *** point-to-point collection leads to long collection paths,so a triangle optimization strategy is then proposed that finds a compromise path to shorten the collection path based on the geometric distribution and energy of sensor *** avoid the coverage hole caused by the death of sensor nodes,the deployment of mobile sensor nodes and the preventive mechanism design are *** emergency data transmission mechanism is further proposed to reduce the latency of collecting the latency-sensitive data due to the absence of *** with the existing schemes,the proposed scheme can prolong the lifetime of the UAVassisted WSN at least by 360%,and shorten the collection path of UAVs by 56.24%.

关键词： Monte-Las search strategy triangle path optimization unmanned aerial vehicles wireless sensor networks

Dynamic event-triggered fault-tolerant cooperative resilient tracking control with prescribed performance for UAVs

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Science China(Information Sciences) 2024年第8期67卷 67-84页

作者： Rong yuan Zhengcai AN Shuyi shao Mou CHEN Mihai LUNGU College of Automation Engineering Nanjing University of Aeronautics and Astronautics Science and Technology on Electro-optic Control Laboratory Faculty of Electrical Engineering University of Craiova Aerospace Engineering Doctoral School University Politehnica of Bucharest

In this paper, a resilient tracking control scheme with cooperative collision avoidance performance is studied for the fixed-wing unmanned aerial vehicle(UAV) leader-follower formation in the presence of actuator failures and external disturbances. Firstly, based on the control objectives of UAV formation tracking and collision avoidance, the transformation tracking errors are obtained using the prescribed performance control technique. Next, a fault detection mechanism is introduced to determine if there is the actuator fault. Subsequently, the event-triggered resilient fault observers are designed based on a dynamic eventtriggered mechanism to estimate actuator faults. Furthermore, the prescribed performance functions and the H∞ performance index are employed to ensure the UAV formation collision-free and mitigate the impact of disturbances. Moreover, the resilient controller is designed to minimize the effect of the perturbations for the control gain and the fault observer gain on the system. The stability of the system is also proven through the Lyapunov stability analysis, and the controller gains are calculated by solving the linear matrix ***, the validity of the proposed control strategy is demonstrated by the simulation analysis.

关键词： cooperative collision avoidance event-triggered fault observer prescribed performance resilient control UAV formation

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Spin asymmetry and dipole moments inτ-pair production with ultraperipheral heavy ion collisions

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Science China(Physics,Mechanics & Astronomy) 2024年第8期67卷 15-21页

作者： Dingyu shao Bin Yan Shu-Run yuan Cheng Zhang Department of Physics Center for Field Theory and Particle PhysicsFudan UniversityShanghai 200433China Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Fudan UniversityShanghai 200433China Shanghai Research Center for Theoretical Nuclear Physics National Natural Science Foundation of China(NSFC)and Fudan UniversityShanghai 200438China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China School of Physics Peking UniversityBeijing 100871China

The anomalous magnetic(MDM)and electric(EDM)dipole moments of theτlepton serve as crucial indicators of new physics beyond the standard *** azimuthal angular asymmetry as a novel tool in ultraperipheral collisions(UPCs),we attain unparalleled precision in the study of these key *** by the highly linear polarization of coherent photons,this method uniquely enables both the MDM and EDM to contribute to the cos 2φangular distribution in similar ***,our approach substantially narrows the parameter space,excluding more than half of it compared to expected UPC-based measurements reliant solely on the total *** method not only provides improved constraints but also minimizes the need for additional theoretical assumptions,and offers a novel avenue to probe the EDM effects.

关键词： ultraperipheral collisions magnetic and electric dipole moments spin asymmetry

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