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Real-time transition dynamics and stability of chipscale dispersion-managed frequency microcombs

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Light(Science & Applications) 2020年第1期9卷 1520-1529页

作者： Yongnan Li Shu-Wei Huang Bowen Li Hao Liu Jinghui Yang Abhinav Kumar Vinod Ke Wang Mingbin Yu dim-lee kwong Hui-Tian Wang Kenneth Kin-Yip Wong Chee Wei Wong Fang Lu Mesoscopic Optics and Quantum Electronics Laboratory University of CaliforniaLos AngelesCA 90095USA School of Physics and The MOE Key Laboratory of Weak Light Nonlinear Photonics Nankai UniversityTianjinChina Department of Electrical Computer and Energy EngineeringUniversity of Colorado BoulderBoulderCO 80309USA Department of Electrical and Electronic Engineering The University of Hong KongHong KongChina Institute of Microelectronics A*STARSingapore 117865Singapore

Femtosecond mode-locked laser frequency combs have served as the cornerstone in precision spectroscopy,alloptical atomic clocks,and measurements of ultrafast *** frequency microcombs based on nonlinear microresonators have been examined,exhibiting remarkable precision approaching that of laser frequency combs,on a solid-state chip-scale platform and from a fundamentally different physical *** recent successes,to date,the real-time dynamical origins and high-power stabilities of such frequency microcombs have not been fully ***,we unravel the transitional dynamics of frequency microcombs from chaotic background routes to femtosecond mode-locking in real time,enabled by our ultrafast temporal magnifier metrology and improved stability of dispersion-managed dissipative *** our dispersion-managed oscillator,we further report a stability zone that is more than an order-of-magnitude larger than its prior static homogeneous counterparts,providing a novel platform for understanding ultrafast dissipative dynamics and offering a new path towards high-power frequency microcombs.

关键词： dispersion stability dynamics

Stimulated generation of deterministic platicon frequency microcombs

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Photonics Research 2022年第8期10卷 1877-1885页

作者： HAO LIU SHU-WEI HUANG WENTING WANG JINGHUI YANG MINGBIN YU dim-lee kwong PIERRE COLMAN CHEE WEI WONG Fang Lu Mesoscopic Optics and Quantum Electronics Laboratory University of California Los AngelesLos AngelesCalifornia 90095USA Department of Electrical Computerand Energy EngineeringUniversity of Colorado BoulderBoulderColorado 80309USA Institute of Microelectronics SingaporeSingapore Universitéde Bourgogne Franche-Comté ICBUMR CNRS 6303DijonFrance

Dissipative Kerr soliton generation in chip-scale nonlinear resonators has recently observed remarkable advances,spanning from massively parallel communications, to self-referenced oscillators, and to dual-comb *** working in the anomalous dispersion regime, unique driving protocols and dispersion in these nonlinear resonators have been examined to achieve the soliton and soliton-like temporal pulse shapes and coherent frequency comb generation. The normal dispersion regime provides a complementary approach to bridge the nonlinear dynamical studies, including the possibility of square pulse formation with flattop plateaus, or *** we report observations of square pulse formation in chip-scale frequency combs through stimulated pumping at one free spectral range and in silicon nitride rings with +55 fs~2∕mm normal group velocity *** of the platicon frequency comb via a varied sideband modulation frequency is examined in both spectral and temporal measurements. Determined by second-harmonic autocorrelation and cross correlation, we observe bright square platicon pulse of 17 ps pulse width on a 19 GHz flat frequency comb. With auxiliary-laser-assisted thermal stabilization, we surpass the thermal bistable dragging and extend the mode-locking access to narrower 2 ps platicon pulse states, supported by nonlinear dynamical modeling and boundary limit discussions.

关键词： pumping soliton dispersion

Real-time dynamics and cross-correlation gating spectroscopy of free-carrier Drude slow-light solitons

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Light(Science & Applications) 2017年第1期6卷 729-736页

作者： Heng Zhou Shu-Wei Huang Xiujian Li James F McMillan Chi Zhang Kenneth Kin-Yip Wong Mingbin Yu Guo-Qiang Lo dim-lee kwong Kun Qiu Chee Wei Wong Key Lab of Optical Fiber Sensing and Communication Networks University of Electronic Science and Technology of ChinaChengdu 611731China Optical Nanostructures Laboratory Columbia UniversityNew YorkNY 10027USA Mesoscopic Optics and Quantum Electronics Laboratory University of CaliforniaLos AngelesCA 90095USA College of Science National University of Defense TechnologyChangshaHunan 410073China Department of Electrical and Electronic Engineering The University of Hong KongHong KongChina Institute of Microelectronics Agency for ScienceTechnology and ResearchScience ParkⅡSingapore 117685Singapore

Optical solitons—stable waves balancing delicately between nonlinearities and dispersive effects—have advanced the field of ultrafast optics and dynamics,with contributions spanning from supercontinuum generation to soliton fission,optical event horizons,Hawking radiation and optical rogue waves,among ***,we investigate picojoule soliton dynamics in silicon slow-light,photonic-bandgap waveguides under the influence of Drude-modeled,free-carrier-induced nonlinear *** real-time and single-shot amplified dispersive Fourier transform spectroscopy simultaneously with high-fidelity cross-correlation frequency resolved optical gating at femtojoule sensitivity and femtosecond resolution,we examine the soliton stability limits,the soliton dynamics including free-carrier quartic slow-light scaling and acceleration,and the Drude electron–hole plasma-induced perturbations in the Cherenkov radiation and modulation *** real-time single-shot and time-averaged cross-correlation measurements are matched with our detailed theoretical modeling,examining the reduced group velocity free-carrier kinetics on solitons at the picojoule scale.

关键词： nonlinear kinetics optical solitons photonic bandgap materials

Effect of pipe installation and external load on buried steel pipe responses:Experimental and numerical investigations

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Underground Space 2024年第2期15卷 44-58页

作者： Yadong Zhang Ron Chik-kwong Wong Jianfeng Chen Wei Su Department of Civil Engineering Schulich School of EngineeringUniversity of CalgaryCalgaryAB T2N 1N4Canada Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China

During pipe installation,compacting soil at pipe sides causes an initial pipe deformation which is known as the"peaking"***,in conventional pipe design codes,only pipe deformation caused by vertical overburden is considered while the"peaking"effect is *** this study,a full-scale test was conducted on a Grade X52 steel pipe with a diameter of 600 mm to investigate the impacts of both soil compaction and vertical overburden on pipe *** compaction and external load were found to elongate and shorten the vertical pipe diameter,***"peaking"effect was observed during the installation procedure accompanied by the highest pipe stress measured at the pipe ***,a two-dimensional finite element model was created and validated based on the calculated pipe stresses from the experimental study.A parametric study was performed thereafter to numerically study the impacts of soil water content,pipe wall thickness,compaction pressure,and lift thickness on pipe responses due to soil compaction and external *** increase in the"peaking"effect is observed with increasing soil water content and compaction pressure,while an increase in pipe wall thickness or lift thickness would cause a decrease in the"peaking"effect.

关键词： X52 steel Soil compaction External load Peaking effect Pipe deflection Soil arching

Effect of non-uniform swelling on coal multiphysics during gas injection: The triangle approach

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1362-1372页

作者： Yifan Huang Jishan Liu Yaoyao Zhao Derek Elsworth Yee-kwong Leong Department of Chemical Engineering School of EngineeringThe University of Western Australia35 Stirling HighwayWA 6009Australia State Key Laboratory of Coal Resources & Safe Mining China University of Mining& TechnologyBeijing100803China Department of Energy and Mineral Engineering G3 Centre and Energy InstituteThe Pennsylvania State UniversityUniversity ParkPA16802USA

In current dual porosity/permeability models,there exists a fundamental assumption that the adsorption-induced swelling is distributed uniformly within the representative elementary volume (REV),irrespective of its internal structures and transient ***,both internal structures and transient processes can lead to the non-uniform *** this study,we hypothesize that the non-uniform swelling is responsible for why coal permeability in experimental measurements is not only controlled by the effective stress but also is affected by the adsorption-induced *** propose a concept of the swelling triangle composed of swelling paths to characterize the evolution of the non-uniform swelling and serve as a core link in coupled multiphysics.A swelling path is determined by a dimensionless volumetric ratio and a dimensionless swelling *** swelling paths have the same start and end point,and each swelling path represents a unique swelling *** swelling path as the diagonal of the triangle represents the case of the uniform swelling while that as the two perpendicular boundaries represents the case of the localized *** paths of all intermediate cases populate inside the *** corresponding relations between the swelling path and the response of coal multiphysics are established by a non-uniform swelling *** define this method as the triangle approach and corresponding models as swelling path-based *** proposed concept and models are verified against a long-term experimental measurement of permeability and strains under constant effective *** results demonstrate that during gas injection,coal multiphysics responses have a close dependence on the swelling path,and that in both future experiments and field predictions,this dependence must be considered.

关键词： Transient process Heterogeneity Swelling triangle Swelling path Non-uniform swelling coefficient

Oxidative spirolactonisation for modular access of γ-spirolactones via a radical tandem annulation pathway

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Chinese Chemical Letters 2024年第10期35卷 249-252页

作者： Jindian Duan Xiaojuan Ding Pui Ying Choy Binyan Xu Luchao Li Hong Qin Zheng Fang Fuk Yee kwong Kai Guo College of Biotechnology and Pharmaceutical Engineering State Key Laboratory of Materials-Oriented Chemical EngineeringNanjing Tech UniversityNanjing 211816China Department of Chemistry and State Key Laboratory of Synthetic Chemistry The Chinese University of Hong KongHong KongChina

An oxidative annulation of 2-arylidene-1,3-indanediones with Meldrum's acid has been developed for the divergent syntheses of spirolactones with a spirocenter located at theγ-position with respect to the carbonyl *** heteroannulation protocol tolerates various functional groups and delivers moderate-to-good product ***,the reaction outcomes are exclusively controlled by the reaction oxidant/*** annulation strategy can also be executed in the flow system with decent product *** experiments revealed that the reaction proceeds via a radical tandem annulation pathway.

关键词： Spirolactonisation y-Spirolactones 2-Arylidene-1,3-indanediones Meldrum's acid Divergentsynthesis

On Product-Cordial Index Sets and Friendly Index Sets of 2-Regular Graphs and Generalized Wheels

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Acta Mathematica Sinica,English Series 2012年第4期28卷 661-674页

作者： Harris kwong Sin Min lee Ho Kuen NG Department of Mathematical Science SUNY Fredonia Department of Computer Science San Jose State University Department of Mathematics San Jose State University

A vertex labeling f ： V →Z2 of a simple graph G = （V, E） induces two edge labelings The friendly index set and the product-cordial index set of G are defined as the setsf is friendly}. In this paper we study and determine the connection between the friendly index sets and product-cordial index sets of 2-regular graphs and generalized wheel graphs.

关键词： Friendly index set product cordial index set 2-regular graphs generalized wheels

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进化双层自适应局部特征选择

计算机应用 2024年第5期44卷 1408-1414页

作者：高麟周宇邝得互深圳大学计算机与软件学院广东深圳518060 岭南大学电脑及决策科学系中国香港999077

局部特征选择(LFS)方法将样本空间划分为多个局部区域,并为每个区域选择最优特征子集以反映局部异质信息。然而,现有的LFS方法以每个样本为中心划分局部区域并找到最优特征子集,导致优化效率低下且适用场景受限。为了解决这个问题,提出... 详细信息

局部特征选择(LFS)方法将样本空间划分为多个局部区域,并为每个区域选择最优特征子集以反映局部异质信息。然而,现有的LFS方法以每个样本为中心划分局部区域并找到最优特征子集,导致优化效率低下且适用场景受限。为了解决这个问题,提出一种进化双层自适应局部特征选择(BiLFS)算法。LFS问题被建模为双层优化问题,特征子集和待优化局部区域是该问题的两个决策变量。在问题的上层,使用非支配排序遗传算法-Ⅱ求解被选择的局部区域的最优特征子集,区域纯度和被选择特征比率是目标函数;在问题的下层,根据上层求解的最优特征子集,首先使用局部区域聚类分析得到区域内的中心样本,然后通过局部区域融合消除非必要区域并更新必要区域的种群。在11个UCI数据集上的测试结果表明,相较于基于进化算法的非自适应LFS方法,BiLFS的平均分类准确率达到前者的98.48%,而平均所需计算用时仅为前者的9.51%,运算效率得到大幅提升,且达到基于线性规划的LFS方法的水准。对迭代过程中BiLFS算法选择的用于优化的局部区域进行可视化分析,结果表明,BiLFS选择必要局部区域具有稳定性和可靠性。

关键词：特征选择双层优化遗传算法多目标优化聚类

钯催化的碳(sp^(3))-硅键转化实现碳(sp^(3))-碳(sp^(2))偶联制备三氟丙基(杂)芳烃

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有机化学 2024年第4期44卷 1319-1326页

作者：刘君君卢涛涛马平赵庆阳邝福儿中山大学·深圳药学院(深圳) 广东深圳518107 香港中文大学化学系中国香港

使用商业可得的三烷氧基三氟丙基硅试剂,通过钯催化的碳(sp^(3))-硅键转化实现了C(sp^(3))—C(sp^(2))偶联反应.该偶联反应方法具有良好的官能团兼容性,可以有效制备一系列含多种官能团的三氟丙基(杂)芳烃.氟离子添加剂和双膦配体的脂... 详细信息

使用商业可得的三烷氧基三氟丙基硅试剂,通过钯催化的碳(sp^(3))-硅键转化实现了C(sp^(3))—C(sp^(2))偶联反应.该偶联反应方法具有良好的官能团兼容性,可以有效制备一系列含多种官能团的三氟丙基(杂)芳烃.氟离子添加剂和双膦配体的脂肪链的调节对于提高反应效率有重要的作用.

关键词：钯催化桧山偶联反应氟烷基化有机硅试剂