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Magnetic Flux alignment Studies on Entrapped Ferrofuid Nanoparticles in Poly Vinyl Alcohol Matrix

Journal of Materials Science & Technology 2013年第10期29卷 903-908页

作者： K.Jeyasubramanian N.Selvakumar J.Ilakkiya P.Santhoshkumar Nikil Satish Sumanta Kumar Sahoo Nano Science and Technology Lab Department of Mechanical EngineeringMepco Schlenk Engineering College Department of ECE Jay Shriram Group of Institutions Department of ECE Adhiyamaan College of Engineering Department of Metallurgical and Materials Engineering National Institute of Technology

Highly surface active super paramagnetic colloidal suspensions of nano crystalline ferrofluid have been synthesized through wet-chemical route. Entrapment of magnetic domains presented in the nano ferrofluid in a polymer matrix like poly vinyl alcohol film was accomplished by developing polymer composite film in between two magnetic poles by solvent casting method. Similarly poly vinyl alcohol-ferrofluid composite films were also developed in the absence of magnetic field. Atomic force microscopy image of nano-composite film makes it clear that the film developed in the absence of magnetic field possesses randomly oriented domains, whereas film developed with magnetic field shows well aligned flux lines. The characteristics and nature of forces acting between magnetic domains along the magnetic flux lines were explored from magnetic force microscopy imaging. The number of flux lines developed in the polymer matrix was observed to be directly proportional to applied external magnetic field. Approximate number of magnetic lines passing through unit area of composite film was evaluated from line profile data analysis of atomic force microscopy image. The particle sizes of the nanoparticles encapsulated in the polymer matrix were found to be in the range of 10- 20 nm. Scanning electron microscopy micrographs confirm aggregation of ferrofluid particles of ribbon like morphology along the magnetic flux lines. Magnetic properties of the entrapped nanoparticles in polymer matrix film were analyzed using vibrating sample magnetometer at room temperature. The super paramagnetic nature and other magnetic properties were evaluated from the hysteresis loop.

关键词： Ferrofiuid Magnetic field fines alignment Super paramagnetic

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Initial alignment of compass based on genetic algorithm-particle swarm optimization

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Defence Technology（防务技术） 2020年第1期16卷 257-262页

作者： Yi-feng Liang Peng-fei Jiang Jiang-ning Xu Wen An Miao Wu College of Electrical Engineering Naval Univ.of EngineeringWuhan 430033China

The rapidity and accuracy of the initial alignment influence the performance of the strapdown inertial navigation system(SINS),compass alignment is one of the most important methods for initial *** selection of the parameters of the compass alignment loop directly affects the result of ***,the optimal parameters of the compass loop of different SINS are also different Traditionally,the alignment parameters are determined by experience and trial-and-error,thus it cannot ensure that the parameters are *** this paper,the Genetic Algorithm-Particle Swarm Optimization(GA-PSO) algorithm is proposed to optimize the compass alignment parameters so as to improve the performance of the initial alignment of strapdown *** experiment results showed that the GA-PSO algorithm can find out the optimal parameters of the compass alignment circuit quickly and accurately and proved the effectiveness of the proposed method.

关键词： Inertial alignment Genetic algorithm SINS Compass alignment

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Unscented Kalman filter for SINS alignment

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Journal of Systems Engineering and Electronics 2007年第2期18卷 327-333页

作者： Zhou Zhanxin Gao Yanan Chen Jiabin Dept. of Automatic Controls Beijing Inst. of Technology Beijing 100081 P. R. China

In order to improve the filter accuracy for the nonlinear error model of strapdown inertial navigation system （SINS） alignment, Unscented Kalman Filter （UKF） is presented for simulation with stationary base and moving base of SINS alignment. Simulation results show the superior performance of this approach when compared with classical suboptimal techniques such as extended Kalman filter in cases of large initial misalignment. The UKF has good performance in case of small initial misalignment.

关键词： Unscented Kalman filter Strapdown inertial navigation alignment Extended Kalman filter.

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Incremental alignment Manifold Learning

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Journal of Computer Science & Technology 2011年第1期26卷 153-165页

作者：韩志孟德宇徐宗本古楠楠 Institute for Information and System Sciences Xi'an Jiaotong University

A new manifold learning method, called incremental alignment method （IAM）, is proposed for nonlinear dimensionality reduction of high dimensional data with intrinsic low dimensionality. The main idea is to incrementally align low-dimensional coordinates of input data patch-by-patch to iteratively generate the representation of the entire ***. The method consists of two major steps, the incremental step and the alignment step. The incremental step incrementally searches neighborhood patch to be aligned in the next step, and the alignment step iteratively aligns the low-dimensional coordinates of the neighborhood patch searched to generate the embeddings of the entire dataset. Compared with the existing manifold learning methods, the proposed method dominates in several aspects： high efficiency, easy out-of-sample extension, well metric-preserving, and averting of the local minima issue. All these properties are supported by a series of experiments performed on the synthetic and real-life datasets. In addition, the computational complexity of the proposed method is analyzed, and its efficiency is theoretically argued and experimentally demonstrated.

关键词： alignment incremental learning manifold learning nonlinear dimensionality reduction out-of-sample issue

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New measuring method of fiber alignment in precision torsion pendulum experiments

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Chinese Physics B 2020年第8期29卷 162-167页

作者： Bing-Jie Wang Li Xu Wei-You Zeng Qing-Lan Wang College of Science Hubei University of Automotive and TechnologyShiyan 442002China

Testing the extreme weak gravitational forces between torsion pendulum and surrounding objects will indicate new physics which attracts many *** these measurements,the fiber alignment plays a crucial role in fulfilling high precision placement measurement,especially in measuring the deviation between the fiber and source mass or other *** traditional way of the fiber alignment requires to measure the component of the pendulum body and then transfer to the torsion fiber by some complicated calculations.A new method is reported here by using a CCD camera to get the projection image of the torsion fiber,which is a direct and no-contact ***,the relative position change of the torsion fiber can also be monitored during the *** our experiment,the alignment between the fiber and the center of the turntable has been operated as an *** result reaches the accuracy of several micrometers which is higher than the previous method.

关键词： torsion pendulum alignment CCD camera

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Imaging alignment of rotational state-selected CH_3I molecule

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Chinese Physics B 2019年第2期28卷 167-172页

作者： Le-Le Song Yan-Hui Wang Xiao-Chun Wang Hong-Tao Sun Lan-Hai He Si-Zuo Luo Wen-Hui Hu Dong-Xu Li Wen-Hui Zhu Ya-Nan Sun Da-Jun Ding Fu-Chun Liu Institute of Atomic and Molecular Physics Jilin University Jilin Institute of Chemical Technology Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy Jilin University College of Electronic Science and Engineering State Key Laboratory on Integrated OptoelectronicsJilin University General Hospital of FAW

We experimentally and numerically investigate CH_3I molecular alignment by using a femtosecond laser and a hexapole. The hexapole provides the single |111〉rotational state condition at 4.5-kV hexapole rod voltage. Based on this single rotational state, an enhanced alignment degree of 0.73 is achieved. Our experimental results are in agreement with the simulation results. We experimentally obtain the ion velocity map images and show the influence of the initial rotational-state population. With the I+ion images and angular distributions at different pump-probe delay time, the alignment and anti-alignment phenomena are further demonstrated. The molecules will be under field-free conditions when the laser effect disappears completely at the full revival time. Our work shows that the quantum control and spatial control on CH_3I molecules can be realized and molecular coordinate frame can be obtained for further molecular experiment.

关键词： hexapole state selection velocity map imaging alignment

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Curvature-controlled band alignment transition in 1D van der Waals heterostructures

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npj Computational Materials 2023年第1期9卷 1411-1419页

作者： Shu Zhao Chunxia Yang Ziye Zhu Xiaoping Yao Wenbin Li School of Materials Science and Engineering Zhejiang University310027 HangzhouChina Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province School of EngineeringWestlake University310030 HangzhouChina Institute of Advanced Technology Westlake Institute for Advanced Study310024 HangzhouChina

The effect of curvature on the band alignment of one-dimensional (1D) van der Waals (vdW) transition metal dichalcogenide(TMDC) heterostructures is studied by comprehensive first-principles calculations. We find that, as the diameter of a TMDCnanotube decreases, the combined effect of curvature-induced flexoelectricity and circumferential tensile strain causes a rapidlowering of the conduction band minimum, whereas the valence band maximum exhibits an initial lowering before rising. Asindividual TMDC nanotubes form coaxial heterostructures, the concerted effect of diameter-dependent band-edge levels andintertube coupling via flexovoltage can result in a transition of intertube band alignment from Type II to Type I in multipleheterostructural systems, including large-diameter MoSe_(2)@WS_(2), MoTe_(2)@MoSe_(2), and MoTe_(2)@WS_(2) heterostructures. These results laydown a foundation for the rational design of 1D vdW heterostructures.

关键词： alignment curvature band

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alignment of Multi-walled Carbon Nanotubes in Polyacrylonitrile Fibers by Mechanical Drawing

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Journal of Donghua University(English Edition) 2010年第3期27卷 330-334页

作者：王彪文志伟彭锟王华平 State Key Laboratory for Modification of Chemical Fiber and Polymers College of Material Science and EngineeringDonghua University

Polyacrylonitrile(PAN)/multi-walled carbon nanotubes(MWNTs)nanocomposites were prepared by an in-situ polymerization method and the fibers from these composites were obtained by a wet-spinning *** orientation behavior of MWNTs in the PAN fibers was investigated by X-ray diffraction and sound velocity *** dispersion and the alignment of the nanotubes were also studied by scanning electron microscopy.

关键词： alignment mechanical drawing in-situ polymerization polyacrylonitrile carbon nanotubes

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Facet-dependent Cu2O nanocrystals in manipulating alignment of liquid crystals and photomechanical behaviors

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Nano Research 2016年第9期9卷 2581-2589页

作者： Qian Wang Yang Shang Li Yu Cheng Zou Wenhuan Yao Dongyu Zhao Ping Song Huai Yang Lin Guo Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology Ministry of EducationSchool of Chemistry and EnvironmentBeihang UniversityBeijing 100191China Key Laboratory of Micro-Nano Measurement-Manipulation and Physics Ministry of EducationSchool of Physics and Nuclear Energy EngineeringBeihang UniversityBeijing 100191China Department of Advanced Materials & Nanotechnology College of EngineeringPeking UniversityBeijing 100871China

Manipulating the alignment of liquid crystals (LCs) is a hot and fundamental issue for their applications in block copolymers, photonics, actuators, biosensors, and liquid-crystal displays. Here, the surface characteristic of Cu2O nanocrystals was well controlled to manipulate the orientation of the LCs. The mechanism of the orientation of the LCs induced by Cu2O nanocrystals was elucidated based on the interaction between the LCs and Cu2O nanocrystals. To comprehensively prove our assumption, different types of LCs (nematic, cholesteric, and smectic) as well as the same type of LCs with different polarities were selected in our system. Moreover, the photomechanical behaviors of the LC polymer composites demonstrated that the alignment of LCs can be effectively manipulated using Cu2O nanocrystals. [Figure not available: see fulltext.] © 2016, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

关键词： facet-dependent Cu2O nanocrystals alignment liquid crystals photoactuators

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Insight into band alignment of Zn(O,S)/CZTSe solar cell by simulation

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Chinese Physics B 2019年第4期28卷 408-414页

作者： Zhen-Wu Jiang Shou-Shuai Gao Si-Yu Wang Dong-Xiao Wang Peng Gao Qiang Sun Zhi-Qiang Zhou Wei Liu Yun Sun Yi Zhang Institute of Photoelectronic Thin Film Devices and Technology Tianjin Key Laboratory of Photoelectronic Thin Film Devices and Technology Tianjin Institute of Power Source

Cd-free kesterite structured solar cells are currently attracting attention because they are environmentally friendly. It is reported that Zn(O,S) can be used as a buffer layer in these solar cells. However, the band alignment is not clear and the carrier concentration of Zn(O,S) layer is low. In this study, the band alignment of the Zn(O,S)/Cu_2 ZnSnSe_4 p–n junction solar cell and the effect of In_2 S_3/Zn(O,S) double buffer layer are studied by numerically simulation with wxAMPS *** optimizing the band gap structure between Zn(O,S) buffer layer and Cu_2 ZnSnSe_4 absorber layer and enhancing the carrier concentration of Zn(O,S) layer, the device efficiency can be improved greatly. The value of CBO is in a range of 0 eV–0.4 eV for S/(S + O)= 0.6–0.8 in Zn(O,S). The In_2 S_3 is mainly used to increase the carrier concentration when it is used as a buffer layer together with Zn(O,S).

关键词： CZTSe band alignment double buffer layer simulation

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