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2. Concentric ring optical traps for orbital rotation of particles

Author

Li Xing, Dan Dan, Yu Xianghua, Zhou Yuan, Zhang Yanan, Gao Wenyu, Li Manman, Xu Xiaohao, Yan Shaohui, and Yao Baoli

Subjects
optical tweezers, perfect optical vortices, computer generated hologram, complex amplitude modulation, Physics, QC1-999
Abstract

Optical vortices (OVs), as eigenmodes of optical orbital angular momentum, have been widely used in particle micro-manipulation. Recently, perfect optical vortices (POVs), a subclass of OVs, are gaining increasing interest and becoming an indispensable tool in optical trapping due to their unique property of topological charge-independent vortex radius. Here, we expand the concept of POVs by proposing concentric ring optical traps (CROTs) and apply them to trapping and rotating particles. A CROT consists of a series of concentric rings, each being a vortex whose radius and topological charge can be controlled independently with respect to the other rings. Quantitative results show that the generated CROTs have weak sidelobes, good uniformity, and relatively high diffraction efficiency. In experiments, CROTs are observed to trap multiple dielectric particles simultaneously on different rings and rotate these particles with the direction and speed of rotation depending on the topological charge sign and value of each individual ring. In addition, gold particles are observed to be trapped and rotate in the dark region between two bright rings. As a novel tool, CROTs may find potential applications in fields like optical manipulation and microfluidic viscosity measurements.

Published
2023
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5. The impact of uncertain financial risk on the operation efficiency of banks

Author

Li Huizhi and Yu Xianghua

Subjects
New dynamic network, DEA, Malmquist index, Total factor productivity, Bank operating efficiency, Science (General), Q1-390, Social sciences (General), H1-99
Abstract

This paper introduces the latest research on the application of the new dynamic network DEA method in the measurement of the operating efficiency of the banking industry, and measures the operating efficiency of 15 listed banks in China by using the directional distance function (DDF) and the new dynamic network DEA model combined with the Malmquist index. To effectively evaluate the impact of uncertain financial risks on the operating efficiency of banks, we respectively selected the measurement indicators of total assets, number of employees, deposits, and net profit to calculate the operating efficiency of banks in the process of medium and long-term investment. According to the actual situation of bank operation, the process of bank operation is divided into the input stage of capital and manpower, the profit stage of capital operation, and operation stage, and a two-stage DEA network model is constructed. By measuring the overall operating efficiency of China's 15 banks from 2017 to 2022, the results show that the new dynamic network DEA model can better distinguish the efficiency of China's banks from the single-stage DEA model. In the new dynamic network model, the total factor productivity of most banks in China is reduced to varying degrees, which is greatly affected by pure technical efficiency.

Published
2023
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19. One-Step UV-Induced Synthesis of Polypyrrole/Ag Nanocomposites at the Water/Ionic Liquid Interface

Author

Yang Xiaoming, Wei Yuyan, Li Liang, Pan Guoliang, Yan Guoping, and Yu Xianghua

Subjects
Polypyrrole, Ag, Ionic liquid, Nanocomposites, Materials of engineering and construction. Mechanics of materials, TA401-492
Abstract

Abstract Polpyrrole (PPy)/Ag nanocomposites were successfully synthesized at the interface of water and ionic liquid by one-step UV-induced polymerization. Highly dispersed PPy/Ag nanoparticles were obtained by controlling the experimental conditions. The results of Fourier-transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy revealed that the UV-induced interface polymerization leaded to the formation of PPy incorporating silver nanoparticles. It was also found that the electrical conductivity of PPy/Ag nanocomposite was about 100 times higher than that of pure PPy.

Published
2009
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22. Plasma hemoglobin and the risk of death in HIV/AIDS patients treated with antiretroviral therapy

Author

Wang, Dayong, primary, Hou, Xiangqing, additional, Yu, Xianghua, additional, Wang, Tao, additional, Ye, Zhenmiao, additional, Li, Jushuang, additional, Su, Feifei, additional, Guo, Chengnan, additional, Peng, Fang, additional, Zhao, Shuzhen, additional, Li, Huihui, additional, Zuo, Jingjing, additional, Su, Dehua, additional, Zhao, Lina, additional, Zhang, Hemei, additional, Chen, Xiangyang, additional, Wang, Ruoqiu, additional, Xie, Qipeng, additional, Zheng, Chao, additional, and Mao, Guangyun, additional

Published
2021
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24. Synthesis and characterization of tantalum(V) metallaheterocycle [([Me.sub.2]N).sub.3]TaN(Si[Me.sub.3])Si[Me.sub.2]C[H.sub.2] and chloro-mixed-amide [([Me.sub.2]N).sub.3]Ta(Cl)[[N(Si[Me.sub.3]).sub.2]]

Author

Cai, Hu, Yu, Xianghua, Chen, Tianniu, Chen, Xue-Tai, You, Xiao-Zeng, and Xue, Ziling

Subjects
Amides -- Chemical properties, Carbon -- Chemical properties, Chemical bonds -- Properties, Chemical compounds -- Composition, Chemical compounds -- Properties, Chemical compounds -- Structure, Chemical reactions -- Analysis, Chemical research -- Analysis, Cyclic compounds -- Chemical properties, Cyclic compounds -- Composition, Hydrogen -- Chemical properties, Coordination compounds -- Chemical properties, Coordination compounds -- Composition, Coordination compounds -- Structure, Tantalum -- Chemical properties
Abstract

A new mixed-amido complex (Me2N)3Ta(C1)[N[(Si[Me.sub.3]).sub.2]] (1) was prepared from the reaction of [([Me.sub.2]N).sub.3]Ta[Cl.sub.2] with 1 equiv, of LiN[(Si[Me.sub.3]).sub.2]. The reactions of 1 with 1 equiv, of LiN[(Si[Me.sub.3]).sub.2] or [([Me.sub.2]N).sub.3]Ta [Cl.sub.2] with 2 equiv, of LiN[(Si[Me.sub.3]).sub.2] gave [([Me.sub.2]N).sub.3]TaN(Si[Me.sub.3])Si[Me.sub.2]C[H.sub.2] (2) with a four-membered metallaheterocyclic ring through [gamma]-hydrogen abstraction. In the solid state, 1 adopts a distorted trigonal bipyramidal geometry with the -N[(Si[Me.sub.3]).sub.2] and -C1 ligands in the equatorial and axial positions, respectively. The X-ray structure of 2 reveals that it is in a distorted trigonal bipyramidal geometry with a planar metallaheterocyclic ring. Key words: tantalum, [gamma]-hydrogen abstraction, C-H activation, amido complexes, metallacycle.

Published
2003

32. Rapid Image Reconstruction of Structured Illumination Microscopy Directly in the Spatial Domain.

Author

Dan, Dan, Wang, Zhaojun, Zhou, Xing, Lei, Ming, Zhao, Tianyu, Qian, Jia, Yu, Xianghua, Yan, Shaohui, Min, Junwei, Bianco, Piero R., and Yao, Baoli

Abstract

Super-resolution structured illumination microscopy (SIM) routinely performs image reconstruction in the frequency domain using an approach termed frequency-domain reconstruction (FDR). Due to multiple Fourier transforms between the spatial and frequency domains, SIM suffers from low reconstruction speed, constraining its applications in real-time, dynamic imaging. To overcome this limitation, we developed a new method for SIM image reconstruction, termed spatial domain reconstruction (SDR). SDR is intrinsically simpler than FDR, does not require Fourier transforms and the theory predicts it to be a rapid image reconstruction method. Results show that SDR reconstructs a super-resolution image 7-fold faster than FDR, producing images that are equal to either FDR or the widely-used FairSIM. We provide a proof-of-principle using mobile fluorescent beads to demonstrate the utility of SDR in imaging moving objects. Consequently, replacement of the FDR approach with SDR significantly enhances SIM as the desired method for live-cell, instant super-resolution imaging. This means that SDR-SIM is a “What You See Is What You Get” approach to super-resolution imaging. [ABSTRACT FROM AUTHOR]

Published
2021
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39. Prevalence of Borrelia burgdorferi Sensu Lato in Ticks from Eastern China

Author

Hou, Juan, primary, Ling, Feng, additional, Chai, Chengliang, additional, Lu, Ye, additional, Yu, Xianghua, additional, Lin, Junfen, additional, Sun, Jimin, additional, Chang, Yue, additional, Ye, Xiaodong, additional, Gu, Shiping, additional, Pang, Weilong, additional, Wang, Chengwei, additional, Zheng, Xiaohua, additional, Jiang, Jianmin, additional, Chen, Zhiping, additional, and Gong, Zhenyu, additional

Published
2015
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42. Unexpected formation of (dimethylaminomethylene)methylamide complexes from the reactions between metal chlorides and lithium dimethylamide

Author

Zhang, Xin-Hao, Chen, Shu-Jian, Cai, Hu, Im, Hee-Jung, Chen, Tianniu, Yu, Xianghua, Chen, Xuetai, Lin, Zhenyang, Wu, Yun-Dong, Xue, Zi-Ling, Zhang, Xin-Hao, Chen, Shu-Jian, Cai, Hu, Im, Hee-Jung, Chen, Tianniu, Yu, Xianghua, Chen, Xuetai, Lin, Zhenyang, Wu, Yun-Dong, and Xue, Zi-Ling

Abstract

Reactions of MCl5 (M = Nb, Ta) with LiNMe2 have been found to yield M(NMe2)(4)(eta(2)-MeNCH2NMe2) (M = Nb, 2a; Ta, 2b) containing a chelating ligand (dimethylaminomethylene)methylamide, as confirmed by NMR spectroscopy, DFT calculations, and their reactivity studies.

Published
2008

44. Reaction of Ta(NMe2)5 with O2: Formation of Aminoxy and Unusual (Aminomethyl)amide Oxo Complexes and Theoretical Studies of the Mechanistic Pathways

Author

Chen, Shu-Jian, Zhang, Xin-Hao, Yu, Xianghua, Qiu, He, Yap, Glenn P.A., Guzei, Ilia A., Lin, Zhenyang, Wu, Yun-Dong, Xue, Zi-Ling, Chen, Shu-Jian, Zhang, Xin-Hao, Yu, Xianghua, Qiu, He, Yap, Glenn P.A., Guzei, Ilia A., Lin, Zhenyang, Wu, Yun-Dong, and Xue, Zi-Ling

Abstract

Reaction of d(0) Ta(NMe2)(5) (1) with O-2 yields two aminoxy complexes (Me2N)(n)Ta(eta(2)-ONMe2)(5-n) (n = 4, 2; 3, 3) as well as (Me2N)(4)Ta-2[eta(2)-N(Me)CH2NMe2](2)(mu-O)(2) (4) and (Me2N)(6)Ta-3[eta(2)-N(Me)CH2NMe2](2)-(eta(2)-ONMe2)(mu-O)(3) (5) containing novel chelating (aminomethyl)amide-N(Me)CH2NMe2 ligands. The crystal structures of 2-5 have been determined by X-ray crystallography. (Me2N)(4)Ta(eta(2)-ONMe2) (2) converts to (Me2N)(3)Ta(eta(2)-ONMe2)(2) (3) in its reaction with O-2. In addition, the reaction of Ta(NMe2)(5) with 3 gives 2 only at elevated temperatures. Density functional theory (DIFT) calculations have been used to investigate the mechanistic pathways in the reactions of Ta(NMe2)(5) (1) with triplet O-2-Monomeric reaction pathways in the formation of 2-5 are proposed. A key step is the oxygen insertion into a Ta-N bond in 1 through an intersystem conversion from triplet to singlet energy surface to give an active peroxide complex (Me2N)(4)-Ta(eta(2)-O-O-NMe2) (A4). The DFT studies indicate that the peroxide ligand plays an important role, including oxidizing an amide to an imine ligand through the abstraction of a hydride. Insertion of Me-N=CH2 into a Ta-amide bond yields the unusual -N(Me)CH2NMe2 ligands.

Published
2007

45. Rotating of low-refractive-index microparticles with a quasi-perfect optical vortex

Author

Liang, Yansheng, Lei, Ming, Yan, Shaohui, Li, Manman, Cai, Yanan, Wang, Zhaojun, Yu, Xianghua, and Yao, Baoli

Abstract

Low-refractive-index microparticles, such as hollow microspheres, have shown great significance in some applications, such as biomedical sensing and targeted drug delivery. However, optical trapping and manipulation of low-refractive-index microparticles are challenging, owing to the repelling force exerted by typical optical traps. In this paper, we demonstrated optical trapping and rotating of large-sized low-refractive-index microparticles by using quasi-perfect optical vortex (quasi-POV) beams, which were generated by Fourier transform of high-order quasi-Bessel beams. Numerical simulation was carried out to characterize the focusing property of the quasi-POV beams. The dynamics of low-refractive-index microparticles in the quasi-POV with various topological charges was investigated in detail. To improve the trapping and rotating performances of the vortex, a point trap was introduced at the center of the ring. Experimental results showed that the quasi-POV was preferable for manipulation of large-sized low-refractive-index microparticles, with its control of the particles’ rotating velocity dependent only on the topological charge due to the unchanged orbital radius.

Published
2018

46. Zirconium, hafnium, and tantalum amide silyl complexes: Their preparation and conversion to metallaheterocyclic complexes via gamma-hydrogen abstraction by silyl ligands

Author

Yu, Xianghua, Bi, Siwei, Guzei, Ilia A., Lin, Zhenyang, Xue, Zi Ling, Yu, Xianghua, Bi, Siwei, Guzei, Ilia A., Lin, Zhenyang, and Xue, Zi Ling

Abstract

New transition metal silyl amide complexes (Me2N)(3)Ta[N(SiMe3)(2)](SiPh2But) (1) and (Me2N)M[N(SiMe3)(2)](2)(SiPh2But) (M = Zr, 2a, and Hf, 2b) were found to undergo gamma-H abstraction by the silyl ligands to give metallaheterocyclic complexes (Me2N)(3)Ta(NSiMe3SiMe2CH2) (3) and {(Me2N)[(Me3Si)(2)N]M(NSiMe3SiMe2CH2)}(2) (M = Zr, 4a, and Hf, 4b), respectively. The conversion of 1 to 3 follows first-order kinetics with DeltaH(double dagger) = 23,6(1.6) kcal/mol and DeltaS(double dagger) = 3(5) eu between 288 and 313 K. The formation of 4a from (Me2N)Zr[N(SiMe3)(2)](2)Cl (5a) and Li(THF)(2)SiPh2Bu1 (6) involves the formation of the intermediate 2a, followed by gamma-H abstraction. Kinetic studies of these consecutive reactions, a second-order reaction to give 2a and then a first-order y-H abstraction to give 4a, were conducted by an analytical method and a numerical method. At 278 K, the rate constants k(1) and k(2) for the two consecufive reactions are 2.17(0.03) x 10(-3) M-1 s(-1) and 5.80(0.15) x 10(-5) s(-1) by the analytical method. The current work is a rare kinetic study of the A + B --> C --> D (+ E) consecutive reactions. Kinetic studies of the formation of a metal laheterocyclic moiety M(NSiMe3SiMe2CH2) have, to our knowledge, not been reported. In addition, gamma-H abstraction by a silyl ligand to give such a metallaheterocyclic moiety is new. Theoretical investigations of the gamma-H abstraction by silyl ligands have been conducted by density functional theory calculations at the Becke3LYP (B3LYP) level, and they revealed that the formation of the metallacyclic complexes through gamma-H abstraction is entropically driven. X-ray crystal structures of (Me2N)(3)Ta[N(SiMe3)(2)](SiPh2But) (1), (Me2N)Zr[N(SiMe3)(2)](2)Cl (5a), and {(Me2N)[(Me3Si)(2)N]M(NSiMe3SiMe2CH2)}(2) (M = Zr, 4a, and Hf, 4b) are also reported.

Published
2004

47. Synthesis, characterization, and theoretical studies of group 4 amido hydrotris(pyrazolyl)borate complexes

Author

Cai, Hu, Lam, Waihan, Yu, Xianghua, Liu, Xiaozhan, Wu, Zhongzhi, Chen, Tianniu, Lin, Zhenyang, Chen, Xuetai, You, Xiaozeng, Xue, Ziling, Cai, Hu, Lam, Waihan, Yu, Xianghua, Liu, Xiaozhan, Wu, Zhongzhi, Chen, Tianniu, Lin, Zhenyang, Chen, Xuetai, You, Xiaozeng, and Xue, Ziling

Abstract

Titanium and zirconium amido complexes containing a hydrotris(pyrazolyl)borate (Tp) or hydrotris(3,5-dimethylpyrazolyl)borate (Tp{*}) ligand TpM(NMe2)(3) (M = Ti, 1; M = Zr, 2) and Tp{*}M(NMe2)(3) (M = Ti, 3; M = Zr, 4) were prepared by the reactions of M(NMe2)(3)Cl (M = Ti, Zr) with sodium hydridotris(pyrazol-1-yl)borate and potassium hydridotris(3,5-dimethylpyrazol-1-yl)borate, respectively. The structures of 1, 2, and 4.CH2Cl2 were determined by X-ray diffraction and show octahedral coordination geometry around the metal centers. Density functional theory calculations at the B3PW91 level were performed to understand the orientations and the rotational behavior of amido ligands in these metal complexes.

Published
2003

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