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A hybrid brain-computer interface control strategy in a virtual environment

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第5期12卷 351-361页

作者： yu su Qiushi Academy.for Advanced Studies Zhejiang University Hangzhou 310022 China School of Computer Science and Technology Zhejiang University Hangzhou 310027 China Department of Biomedical Engineering Zhejiang University Hangzhou 310027 China Key Laboratory of Biomedical Engineering of the Ministry of Education. Hangzhou 310027.China

This paper presents a hybrid brain-computer interface (BCI) control strategy,the goal of which is to expand control functions of a conventional motor imagery or a P300 potential based BCI in a virtual *** hybrid control strategy utilizes P300 potential to control virtual devices and motor imagery related sensorimotor rhythms to navigate in the virtual *** two electroencephalography (EEG) patterns serve as source signals for different control functions in their corresponding system states,and state switch is achieved in a sequential *** the current system,imagination of left/right hand movement was translated into turning left/right in the virtual apartment continuously,while P300 potentials were mapped to discrete virtual device control commands using a five-oddball *** combination of motor imagery and P300 patterns in one BCI system for virtual environment control was tested and the results were compared with those of a single motor imagery or P300-based *** obtained similar performances in the hybrid and single control tasks,which indicates the hybrid control strategy works well in the virtual environment.

关键词： Hybrid brain-computer interface (BCI) control strategy P300 potential Sensorimotor rhythms Virtual environment

Warm white emission of LaSr_(2)F_(7):Dy^(3+)/Eu^(3+)NPs with excellent thermal stability for indoor illumination

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Journal of Materials Science & Technology 2020年第19期54卷 230-239页

作者： Yongbin Hua Jae su yu Department of Electronic Engineering Institute for Wearable Convergence ElectronicsKyung Hee UniversityYongin-siGyeonggi-do 17104Republic of Korea

The novel single Dy^(3+)-activated and Dy^(3+)/Eu^(3+)co-activated LaSr_(2)F_(7) NPs-based phosphors were successfully synthesized via a simple precipitation reaction method at room *** phase formations and cell parameters of single Dy^(3+)-activated and Dy^(3+)/Eu^(3+)co-activated LaSr_(2)F_(7) NPs were verified in detail by the Rietveld refinement technique based on the recorded X-ray diffraction *** doping concentration of single Dy^(3+)-activated LaSr_(2)F_(7) NPs was optimized to be 0.1 mol with the concentration quenching dominated by the electric dipole-dipole ***,a variety of Eu^(3+)-activated La_(0.9)Sr_(2)F_(7):0.1Dy^(3+)NPs exhibited tunable luminescent properties and emitted warm white light in close to standard warm white light under 363 nm *** valid energy transfer(ET)efficiency from Dy^(3+) to Eu^(3+) ions was estimated to be about 86.02%based on the emission intensity while the electric dipole-quadrupole interaction dominated the concentration quenching mechanism in ET ***,the thermal quenching of the obtained samples was studied,showing the excellent thermal *** the results manifest that Eu^(3+)-activated LaSr_(2)F_(7):Dy^(3+)NPs could emit warm white light with excellent thermal stability for indoor illumination.

关键词： Warm white light Energy transfer Thermal stability Chromaticity coordinates

On the behavior of the product of independent random variables

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Science China Mathematics 2006年第3期49卷 342-359页

作者： su Chun CHEN yu Department of Statistics and Finance University of Science and Technology of China Hefei 230026 China Department of Statistics and Finance University of Science and Technology of China Hefei 230026 China

For two independent non-negative random variables X and Y, we treat X as the initial variable of major importance and Y as a modifier (such as the interest rate of a portfolio).Stability in the tail behaviors of the product compared with that of the original variable X is of practical interests. In this paper, we study the tail behaviors of the product XY when the distribution of X belongs to the classes L and S, respectively. Under appropriate conditions, we show that the distribution of the product XY is in the same class as X when X belongs to class L or S, in other words, classes L and S are stable under some mild conditions on the distribution of Y. We also show that if the distribution of X is in class L(γ) (γ＞ 0) and continuous, then the product XY is in L if and only if Y is unbounded.

关键词： independent product, stability, tails of a distribution, heavy-tailed.

Error model identification of inertial navigation platform based on errors-in-variables model

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Journal of Systems Engineering and Electronics 2009年第2期20卷 388-393页

作者： Liu Ming Liu yu su Baoku Space Control and Inertial Technology Research Center Harbin Inst. of Technology Harbin 150001 P. R. China

Because the real input acceleration cannot be obtained during the error model identification of inertial navigation platform, both the input and output data contain noises. In this case, the conventional regression model and the least squares （LS） method will result in bias. Based on the models of inertial navigation platform error and observation error, the errors-in-variables （EV） model and the total least squares （TLS） method axe proposed to identify the error model of the inertial navigation platform. The estimation precision is improved and the result is better than the conventional regression model based LS method. The simulation results illustrate the effectiveness of the proposed method.

关键词： errors-in-variables model total least squares method inertial navigation platform error model identification

Through-Thickness Texture Gradient in Hot-Rolled 25Mn-2.5Si-2Al TWIP Steel

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Journal of Iron and Steel Research International 2013年第4期20卷 46-53页

作者： su yu LI Lin FU Ren-yu Department of Materials Science and Engineering Shanghai University

Texture is one of the important factors affecting sheet metal forming *** through-thickness texture gradient during the hot-rolling process of twinning induced plasticity（TWIP）steel sheet was investigated using electron backscatter diffraction and X-ray *** increasing reduction of the TWIP steel,the fraction of∑1 decreased,whereas the fractions of∑3,∑9,and∑*** 53%reduction,a similar trend could be found from its surface to the *** gradients of intensities of the fibers decreased with increasing hot-rolling *** intensities of face-centered cubic（fcc）shear textures E and Y were higher in the center than that at the surface for both *** 20% reduction,the intensity of fcc plain strain texture S orientation increased from the center to the surface.

关键词： twinning induced plasticity steel texture grain boundary character twinning

The frequency-dependent polarization switching in nanograined BaTiO_(3) films under high-strength electric field

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International Journal of Smart and Nano Materials 2023年第2期14卷 155-169页

作者： Ming-Ran Zhang yu su Department of Mechanics School of Aerospace EngineeringBeijing Institute of TechnologyBeijingP.R.China Department of Mechanical Engineering Quzhou UniversityQuzhouP.R.China

The polarization reorientation in ferroelectric nanomaterials under high-strength AC electric fields is intrinsically a frequency-dependent ***,the related study is not widely *** report a phase-field investigation regarding the dynamics of polarization switching and the electromechanical characteristics of a polycrystalline BaTiO_(3) nanofilm under applied frequency from 0.1 to 80 *** grain boundaries and the in-plane strains are considered in the *** obtained hysteresis and butterfly loops exhibit a remarkable variety of shapes with the changing *** underlying mechanism for the observed frequency-dependent physical properties was discussed via domain structure-based *** addition,we examined the influence of the kinetic coefficient in the Ginzburg-Landau equation as well as the influence of the electric-field amplitude to the frequency *** was found that a higher value of kinetic coefficient or field amplitude tends to enhance the mobility of polarization switching and to transform high-frequency characteristics to low-frequency ones.

关键词： Ferroelectric nanograin grain boundary phase field frequency dependence

Rare-earth and transition metal ion single-/co-doped double-perovskite tantalate phosphors: Validation of suitability for versatile applications

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Journal of Advanced Ceramics 2023年第5期12卷 954-971页

作者： Yongbin Hua Jae su yu Li Li Department of Electronics and Information Convergence Engineering Institute for Wearable Convergence ElectronicsKyung Hee UniversityYongin-si 17104Republic of Korea School of Science Chongqing University of Posts and TelecommunicationsChongqing 400065China

Novel rare-earth (RE;e.g., europium (Eu^(3+)), samarium (Sm^(3+)), and praseodymium (Pr^(3+))) and transition metal (TM^(4+);e.g., manganese (Mn^(4+))) ion single-/co-doped double-perovskite Ca2InTaO6 (CITO) phosphors were prepared and investigated with respect to their crystal structure and photoluminescence (PL) properties. Among them, the CITO:Eu^(3+) phosphors were found to exhibit an ultra-high internal PL quantum yield (89.1%) and good thermal stability (78.7% at 423 K relative to the initial value at 303 K). As such, the corresponding packaged white light-emitting diode (LED) was able to display a remarkable color rendering index (CRI;= 91.51@10 mA). Besides, the potential in applications of anti-counterfeiting fields and a novel LED structure based on flexible phosphor-converted films was also studied. Moreover, due to their different thermal quenching, trivalent lanthanide (Ln^(3+))/Mn^(4+) co-doped CITO phosphors were designed for optical thermometry based on the luminescence intensity ratio (LIR) between different 4f transitions of various Ln^(3+) ions and ^(2)Eg → ^(4)A_(2g) (Mn^(4+)) transition. Particularly, the LIR between the ^(4)G_(5/2) → ^(6)H_(9/2) and ^(2)Eg → ^(4)A_(2g) peaks of the CITO activated with 5 mol% Sm^(3+) and 0.3 mol% Mn^(4+) exhibited the most excellent relative sensitivity (Sr;= 3.80 %·K^(−1)) with beneficial temperature uncertainty of 0.0648 K. Overall, these results are of significance to offer valuable databases for constructing multifunctional high-performance optical platforms using single-/co-doped double-perovskite tantalates.

关键词： phosphors quantum yields(QYs) light-emitting diodes(LEDs) thermometry anti-counterfeiting

Evaluation on the interface characteristics,thermal conductivity,and annealing effect of a hot-forged Cu-Ti/diamond composite

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Journal of Materials Science & Technology 2020年第14期47卷 7-14页

作者： Lei Lei yu su Leandro Bolzoni Fei Yang Waikato Centre for Advanced Materials and Manufacturing School of EngineeringUniversity of WaikatoHamilton3240New Zealand

A Cu-1.5 wt.%Ti/Diamond(55 vol.%)composite was fabricated by hot forging from powder mixture of copper,titanium and diamond powders at 1050?C.A nano-thick TiC interfacial layer was formed between the diamond particle and copper matrix during forging,and it has an orientation relationship of(111)TiC//(002)Cu&[110]TiC//[110]Cuwith the copper *** analysis suggests that TiC is semicoherently bond with copper matrix,which helps reduce phonon scattering at the TiC/Cu interface and facilitates the heat transfer,further leading to the hot-forged copper/diamond composite(referred as to Cu-Ti/Dia-0)has a thermal conductivity of 410 W/m K,and this is about 74%of theoretical thermal conductivity of hot-forged copper/composite(552 W/m K).However,the formation of thin amorphous carbon layer in diamond particle(next to the interfacial TiC layer)and deformed structure in the copper matrix have adverse effect on the thermal conductivity of Cu-Ti/Dia-0 composite.800℃-annealing eliminates the discrepancy in TiC interface morphology between the diamond-{100}and-{111}facets of Cu-Ti/Dia-0 composite,but causes TiC particles coarsening and agglomerating for the Cu-Ti/Dia-2 composite and interfacial layer cracking and spallation for the Cu-Ti/Dia-1 *** addition,a large amount of graphite was formed by titanium-induced diamond graphitization in the Cu-Ti/Dia-2 *** these factors deteriorate the heat transfer behavior for the annealed Cu-Ti/Dia *** heat treatment needs to be continually investigated to improve the thermal conductivity of hot-forged CuTi/Dia composite by eliminating deformed structure in the copper matrix with limit/without impacts on the formed TiC interfacial layer.

关键词： Copper/diamond composite Hot forging Interface characteristics Thermal conductivity Heat treatment

A newly bio-inspired path planning algorithm for autonomous obstacle avoidance of UAV

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Chinese Journal of Aeronautics 2021年第9期34卷 199-209页

作者： Yaoming ZHOU yu su Anhuan XIE Lingyu KONG School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China Intelligent Robot Research Center ZHEJIANG LABZhejiang 311121China

In this paper,a bio-inspired path planning algorithm in 3 D space is *** algorithm imitates the basic mechanisms of plant growth,including phototropism,negative geotropism and *** algorithm proposed in this paper solves the dynamic obstacle avoidance path planning problem of Unmanned Aerial Vehicle(UAV)in the case of unknown environment *** with other path planning algorithms,the algorithm has the advantages of fast path planning speed and fewer route points,and can achieve the effect of low delay real-time path *** feasibility of the algorithm is verified in the Gazebo simulator based on the Robot Operating System(ROS)***,an actual UAV autonomous obstacle avoidance path planning experimental platform is built,and a UAV obstacle avoidance path planning flight test is carried out based on this actual environment.

关键词： Obstacle avoidance Path planning Plant growth ROS UAV