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Spatial cage solitons——taming light bullets

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Photonics Research 2022年第1期10卷 148-154页

作者： CHAO MEI IHAR BABUSHKIN TAMAS NAGY GüNTER STEINMEYER Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy 12489 BerlinGermany School of Computer and Communication Engineering University of Science and Technology Beijing(USTB)Beijing 100083China Institute of Quantum Optics Leibniz University Hannover30167 HannoverGermany Institut für Physik Humboldt Universitat zu Berlin12489 BerlinGermany

Multimode nonlinear optics is used to overcome a long-standing limitation of fiber optics,tightly phase locking several spatial modes and enabling the coherent transport of a wave packet through a multimode fiber.A similar problem is encountered in the temporal compression of multimillijoule pulses to few-cycle duration in hollow gas-filled *** the fiber length to up to 6 m,hollow fibers have recently reached 1 TW of peak *** the remarkable utility of the hollow fiber compressor and its widespread application,however,no analytical model exists to enable insight into the scaling behavior of maximum compressibility and peak *** we extend a recently introduced formalism for describing mode locking to the analog scenario of locking spatial fiber modes *** formalism unveils the coexistence of two soliton branches for anomalous modal dispersion and indicates the formation of stable spatiotemporal light bullets that would be unstable in free space,similar to the temporal cage solitons in mode-locking *** model enables deeper understanding of the physical processes behind the formation of such light bullets and predicts the existence of multimode solitons in a much wider range of fiber types than previously considered possible.

关键词： locking solitons optics

Dynamics of InAs/GaAs quantum dot lasers epitaxially grown on Ge or Si substrate

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Journal of Semiconductors 2019年第10期40卷 74-84页

作者： Cheng Wang Yueguang Zhou School of Information Science and Technology ShanghaiTech UniversityShanghai 201210China Shanghai Institute of Microsystem and Information Technology Chinese Academy of SciencesShanghai 200050China University of Chinese Academy of Sciences Beijing 100049China

Growing semiconductor laser sources on silicon is a crucial but challenging technology for developing photonic integrated circuits(PICs).InAs/GaAs quantum dot(Qdot)lasers have successfully circumvented the mismatch problem betweenⅢ–Ⅴmaterials and Ge or Si,and have demonstrated efficient laser *** this paper,we review dynamical characteristics of Qdot lasers epitaxially grown on Ge or Si,in comparison with those of Qdot lasers on native GaAs *** discuss properties of linewidth broadening factor,laser noise and its sensitivity to optical feedback,intensity modulation,as well as mode locking *** investigation of these dynamical characteristics is beneficial for guiding the design of PICs in optical communications and optical computations.

关键词： quantum dot laser laser noise modulation dynamics mode locking photonic integrated circuits

Finite Element Analysis Study of Prototype of a Novel Intramedullary Injectable Bioresorbable Polymer Fixator versus a Volar Plate for Surgical Treatment of Distal Radius Fractures

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World Journal of Engineering and Technology 2017年第4期5卷 648-667页

作者： Adam Zysk Gladius Lewis Department of Mechanical Engineering The University of Memphis Memphis USA

Complications and shortcomings of volar plating, which is very widely used for surgical treatment of distal radius fractures, are well known. Thus, there is scope for alternative innovative surgical methods. In the present work, we used the finite element analysis method to compare the biomechanical performance of a model of a construct comprising a simulated distal radius fracture considered fixated using a notional intramedullary injectable bioresorbable polymer-bioresorbable balloon osteosynthesis system (“fixator”) versus using a commercially-available volar locking plate (VP). The biomechanical parameters determined were longitudinal stiffness and factor of safety under each of the applied loads.?For the fixator model, 1) each of the biomechanical parameters was markedly influenced by fracture gap fill ratio (FGFR) (defined as the proportion of the volume of the fracture gap that is considered occupied by the expanded polymer-filled balloon)?but not by modulus of elasticity assigned to the polymer;2) with FGFR = 100%, stiffness was comparable to that of the Ti-6Al-4V alloy VP construct model;and 3) stiffness was within the range of literature values for stiffness of constructs comprising simulated fractures in fresh cadaveric distal radii fixated using metal volar locking plate. These results suggest that the fixator may be an alternative modality to metal volar plating and, as such, deserves further evaluation.

关键词： Distal Radius Fracture Volar locking Plate Intramedullary Fixation Finite Element Analysis

Risk Assessment of Retrograde Intramedullary Nailing for Proximal Humeral Fracture

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Journal of Biomedical Science and Engineering 2019年第5期12卷 277-284页

作者： Rina Sakai Uchino Masataka Kazuhiro Yoshida Masanobu Ujihira Department of Biomedical Engineering and Technology School of Allied Health Sciences Kitasato University Sagamihara Japan Department of Orthopedic Surgery Hakujikai Memorial General Hospital Tokyo Japan

In proximal humeral fracture except AO classification 11A1, fixations with a locking plate and nails are recommended. We performed mechanical tests to investigate whether retrograde intramedullary nailing has fixation stability comparable to those of anterograde intramedullary nailing and locking plate which achieve clinically favorable outcomes. In retrograde intramedullary nailing, a nail entry point is made in the diaphysis, for which reduction of stiffness of the humerus is of concern. Thus, we investigated the influence of a nail entry point made in the diaphysis on humeral strength. Retrograde intramedullary nailing had fixation stability against bending and a force loaded in the rotation direction comparable to those of anterograde intramedullary nail and locking plate. Displacement by the main external force loaded on the humerus, compressive load, was less than half in the bone fixed by retrograde intramedullary nailing compared with that in the bone fixed with a locking plate, showing favorable fixation stability. It was clarified that stiffness of the humerus against rotation and a load in the compression direction is not reduced by a nail entry point made by retrograde intramedullary nailing.

关键词： Proximal Humeral Fracture Retrograde Intramedullary Nailing Anterograde Intramedullary Nailing locking Plate Internal Fixation

A Novel Nanotube-Based Fiber Laser for Ultrashort Pulse Generation and Fast Measurements

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Modern Instrumentation 2018年第2期7卷 24-34页

作者： Jie Zhan Jun Qin Siwei Tan Shugang Liu Renlong Zhou Ying Chen College of Physics and Electronic Science Hunan University of Science and Technology Xiangtan China Department of Electrical and Computer Engineering Southern Illinois University Carbondale IL USA

We propose a nanotube-based erbium-doped fiber laser that can deliver conventional soliton (CS) and stretched pulse (SP) based on D-shaped fiber saturable absorber (DF-SA) where evanescent-field interaction works. The novel Nanotube-based Fiber Laser can generate SP or CS by tuning pump power and polarization controller (PC) properly. The net cavity dispersion of laser is slightly negative. In our experiment, by optimizing the PC in the cavity, CS and SP can be obtained at the central wavelengths of 1530.6 nm and 1530.3 nm due to on carbon nanotubes and the spectral filtering effect induced by nonlinear polarization rotation. Although the acquired CS and SP nearly have the same central wavelengths, they show distinct optical spectra, 3-dB bandwidths. The proposed fiber laser with switchable CS and SP is attractive for ultrashort pulse generation and fast measurements in practical applications.

关键词： Ultrashort Pulse Generation Fiber Laser Mode locking Solitons

Compression Test and Finite Element Analysis for Failure Criterion of the Tibial Post of a Posterior-Stabilized Knee Prosthesis

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Journal of Biomedical Science and Engineering 2019年第5期12卷 285-292页

作者： Rina Sakai Urabe Ken Kazuhiro Yoshida Kiyoshi Mabuchi Masanobu Ujihira Department of Biomedical Engineering and Technology School of Allied Health Sciences Kitasato University Sagamihara Japan Department of Orthopedic Surgery Kitasato University Medical Center Kitamoto Japan

Post cam mechanism of Posterior Stabilized (PS) knee prostheses is useful to realize intrinsic stability for cases with severe degeneration. However, some retrieval studies report severe failure of the polyethylene tibial post. We thought that severe failures were caused by high loads during daily activities. In the current study, we performed a compression test and a finite element analysis of the mechanical forces produced in the tibial post in posterior-stabilized knee prostheses in order to develop a specification for the tibial posts found in the polyethylene inserts of PS knee prostheses. Anterior tibial post impingement and posterior tibial post impingement were simulated. The surface pressure values detected in the compression test were consistent with those obtained in the FE analysis. Of the three designs, the lowest von Mises stress values were generated inside the round tibial post;therefore, tibial posts should be round. The risk of tibial post failure was low when 500 or 1000 N was loaded onto the knee joint. It was suggested that tibial post failure occurs when the shear strain at the base of the tibial post exceeds 0.1.

关键词： Proximal Humeral Fracture Retrograde Intramedullary Nailing Anterograde Intramedullary Nailing locking Plate Internal Fixation

Long-term stabilization of the optical fiber phase control using dual PID

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Instrumentation 2015年第4期2卷 40-46页

作者： WU Yue CHEN Guozhu SHEN Yong ZOU Hongxin Department of Physics The National University of Defense Technology Hypervelocity Aerodynamics Institute of CARDC

We propose an approach of long-term stabilization of optical fiber phase by controlling a piezo-based phase modulator and a Peltier component attached to the fiber via a phase-locked loop( PLL) circuit w ith dual proportional-integral- derivative( PID) adjustment. With this approach,we can suppress the fast disturbance and slow drifting of optical fiber to satisfy the requirements of optical phase long-term locking. In theory,a mathematical model of an optical fiber phase control system is established. The disturbance term induced by environment influence is considered into the PLL model. The monotonous and continuous changing environment disturbance w ill cause a steady-state error in this theory model. The experimental results accords w ell w ith the theory. The steady-state performance,adjusting time,and overshoot can be improved by using the dual PID control. As a result,the long-term,highly stable and low noise fiber phase locking is realized experimentally.

关键词： Long-term stabilization dual PID phase locking fiber phase control.

QUALITATIVE ANALYSIS OF THE PHASE LOCKED LOOP OF THE THIRD ORDER WITH TANGENT DISCRIMINATOR CHARACTERISTIC

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Chinese Science Bulletin 1984年第1期29卷 6-9页

作者：王联王慕秋陆志奇 Institute of Mathematics Academia Sinica Beijing Xinxiang Teachers College Henan

As pointed out in [1], the technique of phase locking as a branch of newly developed technology has been widely applied in recent years to many fields such as radio communication, radar, aerospace sciences. A lot of practical and theoretical workers have engaged in the design and theoretical analysis of the second order phase locked loops. Up to the present, for the study of the third order loop, little is found

关键词： engaged aerospace pointed locking branch locked globally satisfying qualitative nowadays

Trilinear Hexahedra with Integral-Averaged Volumes for Nearly Incompressible Nonlinear Deformation

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Engineering（科研） 2015年第11期7卷 765-788页

作者： Craig D. Foster Talisa Mohammad Nejad University of Illinois at Chicago Civil and Materials Engineering Chicago IL USA

Many materials such as biological tissues, polymers, and metals in plasticity can undergo large deformations with very little change in volume. Low-order finite elements are also preferred for certain applications, but are well known to behave poorly for such nearly incompressible materials. Of the several methods to relieve this volumetric locking, the method remains popular as no extra variables or nodes need to be added, making the implementation relatively straightforward and efficient. In the large deformation regime, the incompressibility is often treated by using a reduced order or averaged value of the volumetric part of the deformation gradient, and hence this technique is often termed an approach. However, there is little in the literature detailing the relationship between the choice of and the resulting and stiffness matrices. In this article, we develop a framework for relating the choice of to the resulting and stiffness matrices. We examine two volume-averaged choices for , one in the reference and one in the current configuration. Volume-averaged formulation has the advantage that no integration points are added. Therefore, there is a modest savings in memory and no integration point quantities needed to be interpolated between different sets of points. Numerical results show that the two formulations developed give similar results to existing methods.

关键词： Incompressibility Volumetric locking Strain Projection B-Bar F-Bar Finite Element