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Chinese Physics B 2020年第3期29卷 259-264页

作者： Gepu Guo Ya Gao Yuzhi Li Qingyu Ma Juan Tu Dong Zhang School of Physics and Technology Nanjing Normal UniversityNanjing 210023China Institute of Acoustics Nanjing UniversityNanjing 210093China

Due to the unique magnetic, mechanical and thermal properties, magnetic nanoparticles(MNPs) have comprehensive applications as the contrast and therapeutic agents in biomedical imaging and magnetic hyperthermia. The linear and nonlinear magnetoacoustic responses determined by the magnetic properties of MNPs have attracted more and more attention in biomedical engineering. By considering the relaxation time of MNPs, we derive the formulae of second harmonic magnetoacoustic responses(2H-MARs) for a cylindrical MNP solution model based on the mechanical oscillations of MNPs in magnetoacoustic tomography with magnetic induction(MAT-MI). It is proved that only the second harmonic magnetoacoustic oscillations can be generated by MNPs under an alternating magnetic excitation. The acoustic pressure of the 2H-MAR is proportional to the square of the magnetic field intensity and exhibits a linear increase with the concentration of MNPs. Numerical simulations of the 2H-MAR are confirmed by the experimental measurements for various magnetic field intensities and solution concentrations using a laser vibrometer. The favorable results demonstrate the feasibility of the harmonic measurements without the fundamental interference of the electromagnetic excitation, and suggest a new harmonic imaging strategy of MAT-MI for MNPs with enhanced spatial resolution and improved signal-to-noise ratio in biomedical applications.

关键词： magnetoacoustic tomography with magnetic induction second harmonic magnetoacoustic responses magnetic nanoparticles magnetic force mechanical oscillations

pH-sensitive and biodegradable charge-transfer nanocomplex for second near-infrared photoacoustic tumor imaging

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Nano Research 2019年第1期12卷 49-55页

作者： Zhimin Wang Paul Kumar Upputuri Xu Zhen Ruochong Zhang Yuyan Jiang Xiangzhao Ai Zhijun Zhang Ming Hu Zhenyu Meng Yunpeng Lu Yuanjing Zheng Kanyi Pu Manojit Pramanik Bengang Xing Division of Chemistry and Biological Chemistry School of Physical&Mathematical SciencesNanyang Technological UniversitySingapore 637371Singapore School of Chemical and Biomedical Engineering Nanyang Technological University70 Nanyang DriveSingapore 637459Singapore School of Electrical and Electronic Engineering Nanyang Technological University50 Nanyang AvenueSingapore 639798Singapore

The emerging technique of photoacoustic imaging,especially in the near infra-red(NIR)window,permits high resolution,deep-penetration,clinically reliable ***,few contrast agents are available that can specifically respond to intricate biological environments,and which are biodegradable and ***,we in troduce a new class of pH-sensitive orga nic photoacoustic con trast age nt that operates in the second NIR window(NIR-II,960-1,700 nm),which is derived from the self-assembled charge-transfer nanocomplex(CTN)by 3,3',5,5'-tetramethylbenzidine(TMB)and its dication structure(TMB++).The unique NIR-ll-responsive CTN can specifically respond to pH change in the physiological range and allows noninvasive and sensitive visualization of the tumor acidic microenvironment(*** pH5)in mice with higher signal-to-noise *** CTN is biodegradable under physiological conditions(*** 7.4),which alleviates the biosafety concern of nan oparticle accumulati on in *** results clearly show the pote ntial of the TMB/TMB++-based CTN as a promisi ng pH-activated and biodegradable molecular probe for specific tumor photoacoustic imaging in the NIR-II region.

关键词： charge-transfer nanocomplex second near-infrared window photoacoustic imaging pH-sensitive biodegradable tumor acidic microenvironment

second variation of harmonic maps between Finsler manifolds

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Science China Mathematics 2004年第1期47卷 39-51页

作者： SHEN Yibing ZHANG Yan Department of Mathematics Zhejiang University Hangzhou 310028 China Department of Mathematics Zhejiang University Hangzhou 310028 China

The first and second variation formulas of the energy functional for a nondegenerate map between Finsler manifolds is derived. As an application, some nonexistence theorems of nonconstant stable harmonic maps from a F... 详细信息

关键词： Finsler manifold, harmonic map, second variation.

The second Hopf bifurcation in lid-driven square cavity

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Chinese Physics B 2020年第3期29卷 119-125页

作者： Tao Wang Tiegang Liu Zheng Wang LIMB and School of Mathematical Science Beihang UniversityBeijing 100191China School of Mathematics and Information Science North Minzu UniversityYinchuan 750021China Wuhan Maritime Communication Research Institute Wuhan 430079China

To date, there are very few studies on the second Hopf bifurcation in a driven square cavity, although there are intensive investigations focused on the first Hopf bifurcation in literature, due to the difficulties of theoretical analyses and numerical simulations. In this paper, we study the characteristics of the second Hopf bifurcation in a driven square cavity by applying a consistent fourth-order compact finite difference scheme recently developed by us. We numerically identify the critical Reynolds number of the second Hopf bifurcation located in the interval of(11093.75, 11094.3604) by bisection. In addition, we find that there are two dominant frequencies in its spectral diagram when the flow is in the status of the second Hopf bifurcation, while only one dominant frequency is identified if the flow is in the first Hopf bifurcation via the Fourier analysis. More interestingly, the flow phase portrait of velocity components is found to make transition from a regular elliptical closed form for the first Hopf bifurcation to a non-elliptical closed form with self-intersection for the second Hopf bifurcation. Such characteristics disclose flow in a quasi-periodic state when the second Hopf bifurcation occurs.

关键词： unsteady lid-driven cavity flows second Hopf bifurcation critical Reynolds number numerical simulation

Diagnostics of Femtosecond Laser-Plasmas Using Fundamental and second Harmonic Emission

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Chinese Physics Letters 2000年第11期17卷 818-820页

作者： ZHAO Li-Zeng ZHANG Ping FENG Bao-Hua WEI Zhi-Yi ZHANG Jie Laboratory of Optical Physics Institute of PhysicsChinese Academy of SciencesBeijing 100080 Institute of High Energy Physics Chinese Academy of SciencesBeijing 100039

By observing the fundamental and second harmonic emission from a plasma produced by a 150fs,5mJ laser at 800nm,the electron temperature,the expansion speed and the scalelength of the plasma have been *** the polarization of the fundamental and second harmonic emission has been *** could be a useful diagnostic for modulation at the critical surface of the plasma.

关键词： polarization Femto second

second fundamental forms of holomorphic isometries of the Poincar disk into bounded symmetric domains and their boundary behavior along the unit circle

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Science China Mathematics 2009年第12期52卷 2628-2646页

作者： MOK Ngaiming NG Sui Chung Department of Mathematics The University of Hong Kong

Motivated by problems arising from Arithmetic Geometry,in an earlier article one of the authors studied germs of holomorphic isometries between bounded domains with respect to the Bergman *** the case of a germ of holomorphic isometry f:(Δ,λ ds 2Δ ;0) → (Ω,ds 2Ω ;0) of the Poincar disk Δ into a bounded symmetric domain Ω C N in its Harish-Chandra realization and equipped with the Bergman metric,f extends to a proper holomorphic isometric embedding F:(Δ,λ ds 2Δ) → (Ω,ds 2Ω) and Graph(f) extends to an affine-algebraic variety V  C × C *** of F which are not totally geodesic have been *** arise primarily from the p-th root map ρ p:H → H p and a non-standard holomorphic embedding G from the upper half-plane to the Siegel upper half-plane H 3 of genus *** the current article on the one hand we examine second fundamental forms σ of these known examples,by computing explicitly σ *** the other hand we study on the theoretical side asymptotic properties of σ for arbitrary holomorphic isometries of the Poincar disk into *** such mappings expressing via the inverse Cayley transform in terms of the Euclidean coordinate τ=s + it on the upper half-plane H,we have φ(τ)=t 2 u(τ),where u t=0 ≡ *** show that u must satisfy the first order differential equation u t | t=0 ≡ 0 on the real axis outside a finite number of points at which u is *** a by-product of our method of proof we show that any non-standard holomorphic isometric embedding of the Poincar disk into the polydisk must develop singularities along the boundary *** equation φuφt | t=0 ≡ 0 along the real axis for holomorphic isometries into polydisks distinguishes the latter maps from holomorphic isometries into Siegel upper half-planes arising from *** the end of the article we formulate characterization problems for holomorphic isometries suggested both by the theoretical and the computational results of the article.

关键词： holomorphic isometry Poincar disk Siegel upper half-plane second fundamental form asymptotics

Idealization second Quantization of Composite Particles

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Communications in Theoretical Physics 2001年第11期36卷 525-530页

作者： ZHOU Duan-Lu YU Si-Xia SUN Chang-Pu Institute of Theoretical Physics Academia SinicaBeijing 100080China Institute of Theoretical PhysicsAcademia SinicaBeijing 100080China Institute of Theoretical PhysicsAcademia SinicaBeijing 100080China

A practical method is developed to deal with the second quantization of the many-body system containing the composite *** our treatment,the modes associated with composite particles are regarded approximately as independent ones compared with those of unbound *** field operators of the composite particles thus arise naturally in the second quantization *** be emphasized,the second quantization Hamiltonian has the regular structures which correspond clearly to different physical processes.

关键词： second quantization,composite particles

A theranostic agent for cancer therapy and imaging in the second nearinfrared window

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Nano Research 2019年第2期12卷 273-279页

作者： Zhuoran Ma Hao Wan Weizhi Wang Xiaodong Zhang Takaaki Uno Qianglai Yang Jingying Yue Hongpeng Gao Yeteng Zhong Ye Tian Qinchao Sun Yongye Liang Hongjie Dai Department of Chemistry Stanford University Stanford CA 94305 USA CAS Key Laboratory of Standardization and Measurement for Nanotechnology CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety CAS Center for Excellence in Nanoscience National Center for Nanoscience and Technology of China Beijing 100190 China Department of Physics and Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology School of Sciences Tianjin University Tianjin 300350 China JSR Corporation Advanced Materials Research Laboratories 100 Kawajiri-Cho Yokkaichi Mie 5108552 Japan Department of Materials Science and Engineering South University of Science and Technology of China Shenzhen 518055 China

Thera no stic nano particles are integrated systems useful for simulta neous diag nosis and imaging guided delivery of therapeutic drugs, with wide ranging pote ntial applicati ons in the clinic. Here we developed a thera no stic nan oparticle (~24 nm size by dynamic light scatteri ng) p-FE-PTX-FA based on polymeric micelle encapsulating an organic dye (FE) fluorescing in the 1,000-1,700 nm second near-infrared (NIR-Ⅱ) window and an an ti-ca ncer drug paclitaxel. Folic acid (FA) was conjugated to the nan oparticles to afford specific binding to molecular folate receptors on muri ne breast can cer 4T1 tumor cells. In vivo, the nan oparticles accumulated in 4T1 tumor through both passive and active targeting effect. Under an 808 nm laser excitation, fluorescence detection above 1,300 nm afforded a large Stokes shift, allowing targeted molecular imaging tumor with high signal to background ratios, reaching a high tumor to normal tissue signal ratio (T/NT) of (20.0±2.3). Further, 4T1 tumors on mice were completed eradicated by paclitaxel released from p-FE-PTA-FA within 20 days of the first injection. Pharmacokinetics and histology studies indicated p-FE-PTX-FA had no obvious toxic side effects to major organs. This represented the first NIR-Ⅱ theranostic age nt developed.

关键词： theranostic nanoparticles second near-infrared window fluorescenee imaging cancer therapy

Characterization of domain distributions by second harmonic generation in ferroelectrics

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npj Computational Materials 2018年第1期4卷 339-345页

作者： Yuan Zhang Yi Zhang Quan Guo Xiangli Zhong Yinghao Chu Haidong Lu Gaokuo Zhong Jie Jiang Congbing Tan Min Liao Zhihui Lu Dongwen Zhang Jinbin Wang Jianmin Yuan Yichun Zhou School of Materials Science and Engineering Xiangtan University411105 HunanChina Department of Physics College of ScienceNational University of Defense Technology410073 HunanChina Department of Materials Science and Engineering National Chiao Tung University30010 HsinchuTaiwan Department of Physics and Astronomy University of Nebraska-LincolnLincoln 68588USA

Domain orientations and their volume ratios in ferroelectrics are recognized as a compelling topic recently for domain switching dynamics and domain stability in devices ***,an optimized second harmonic generation method has been explored for ferroelectric domain *** a unique theoretical model with azimuth-polarization-dependent second harmonic generation response,the complex domain components and their distributions can be rigidly determined in ferroelectric thin *** the proposed model,the domain structures of rhombohedral BiFeO_(3) films with 71°and 109°domain wall,and,tetragonal BiFeO_(3),Pb(Zr_(0.2)Ti_(0.8))O_(3),and BaTiO_(3) ferroelectric thin films are analyzed and the corresponding polarization variants are *** work could provide a powerful and all-optical method to track and evaluate the evolution of ferroelectric domains in the ferroelectric-based devices.

关键词： ferroelectric harmonic second

Is serine racemase(SRR) a second hit target for LRRK2-G2019S induced Parkinson's disease?

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Neural Regeneration Research 2021年第3期16卷 498-499页

作者： Sarah Louise Nickels Jens Christian Schwamborn Luxembourg Centre for Systems Biomedicine(LCSB) University of LuxembourgBelvauxLuxembourg Riken Institute for Medical Sciences(IMS) KanagawaJapan

To date,at least 7 million people are suffering from Parkinson's disease(PD)worldwide,which is the second most prevalent,age-associated,and progressive neurodegenerative disorder(Tysnes and Storstein,2017).Given the accelerated global pace of aging,it becomes of fundamental importance that we start understanding the origins of neurodegeneration in order to develop effective disease modifying *** PD patients suffer from a combination of motor and nonmotor disabilities.

关键词： second patients suffering