摘要： The bubble formation dynamics and size manipulation in the slurry of polystyrene microspheres in the microfluidic T-junction were visually investigated by a high-speed camera.Based on the evolution of the bubble neck with time,the formation process of bubbles is divided into three stages:filling,squeezing and pinch-off.The particle concentration has an obvious effect on the squeezing stage,while less impact on the filling and pinch-off stages.In the squeezing stage,the evolution of the dimensionless minimum neck width of bubbles with time could be described by a power-law relationship.The increase of the particle concentration or continuous phase flow rate could lead to the increase of body flow of the continuous phase and the enhancement of the squeezing force acted on the bubble neck,correspondingly,the power-law index a in the squeezing stage enlarges.Moreover,the bubble size increases with the increase of the gas phase flow rate and the decrease of the particle concentration and continuous phase flow rate.However,the effect of the particle concentration on the bubble size weakens with the increase of the continuous phase flow rate.In addition,a new prediction correlation of the bubble size for the slurry system in a T-shape microchannel was proposed with good prediction accuracy.

摘要： This article reviews Fuqing ZHANG’s contributions to mesoscale atmospheric science,from research to mentoring to academic service,over his 20-year career.His fundamental scientific contributions on predictability,data assimilation,and dynamics of high impact weather,especially gravity waves and tropical cyclones,are highlighted.His extremely generous efforts to efficiently transmit to the community new scientific knowledge and ideas through mentoring,interacting,workshop organizing,and reviewing are summarized.Special appreciation is given to his tremendous contributions to the development of mesoscale meteorology in China and the education of Chinese graduate students and young scientists.

摘要： Nucleation widely exists in nature,from cloud formation to haze generation.The classical nucleation theory(CNT)was created to describe the nucleation process,but it fails to predict many experimental phenomena due to the short consideration of nanoscale phenomena and macroscale dynamics.Although the attachment and detachment of monomers are considered in the developed model of nucleation,the diffusion of chemicals in the bulk is not valued as supersaturation in the nucleation process so far.Here we employ simulation and experimental approaches to investigate how the diffusion of ions affects the nucleation of calcium carbonate.The diffusion of ions is regulated by the viscosity of solvents and the sonication imposed on the solution.It is found that the nucleation rates increased exponentially with the diffusion coefficient of ions,which is beyond the prediction of CNT.This abnormal finding might be ascribed to the involvement of cluster aggregation in the nucleation of calcium carbonate.This study highlights the significance of chemical diffusion in the nucleation process,which may help to revise the nucleation theory and develop solutions for the rational synthesis of materials,as well as for the control of air pollution.

摘要： Dear editor,In this letter,we introduce a decentralized,nonlinear,discontinuous,and computationally simple control law for large scale multiagent navigation systems.The control is based on extending Gauss’s principle of least constraint with a dynamic incorporation of inequality constraints,actuator saturation,and actuator dynamics.With no individual path planner,each agent executes its motion and generates its control actions by reacting solely to the evolution of its constrained dynamics,which is equivalent to solving a linear matrix equation with a dimension up to around 20 without iteration at each time instant.Numerical experiments are conducted on hundreds of two-dimensional(2-D)double integrators subjected to path and collision constraints,demonstrating the promise of the proposed method.

摘要： Magnetized laser-produced plasmas are central to many studies in laboratory astrophysics,in inertial confinement fusion,and in industrial applications.Here,we present the results of large-scale three-dimensional magnetohydrodynamic simulations of the dynamics of a laser-produced plasma expanding into a transverse magnetic field with a strength of tens of teslas.The simulations show the plasma being confined by the strong magnetic field into a slender slab structured by the magnetized Rayleigh–Taylor instability that develops at the plasma–vacuum interface.We find that when the initial velocity of the plume is perturbed,the slab can develop kink-like motions that disrupt its propagation.

摘要： It is a difficult task to root the cause of the failure of a gas face seal because different causes may result in similar observations.In the work being presented,the discrimination of multiple types of abnormities in a spiral groove gas face seal is studied.A dynamic model is employed to analyze groups of cases in order to uncover the dynamic behaviors when the face contact is induced by different mixtures of abnormities,whose discriminative features when motion and contact are monitored are studied and uncovered.A circumferential-pattern-related oscillation phenomenon is discovered,which is extracted from contact information and implies the relative magnitude of the moment on stator and the rotor tilt.The experimental observation shows consistent results.It means that the grooves(or other circumferential patterns)generate useful informative features for monitoring.These results provide guidance for designing a monitored gas face seal system.

摘要： The structural evolution of laser-excited systems of gold has previously been measured through ultrafast MeV electron diffraction.However,there has been a long-standing inability of atomistic simulations to provide a consistent picture of the melting process,leading to large discrepancies between the predicted threshold energy density for complete melting,as well as the transition between heterogeneous and homogeneous melting.We make use of two-temperature classical molecular dynamics simulations utilizing three highly successful interatomic potentials and reproduce electron diffraction data presented by Mo et al.[Science 360,1451–1455(2018)].We recreate the experimental electron diffraction data,employing both a constant and temperature-dependent electron–ion equilibration rate.In all cases,we are able to match time-resolved electron diffraction data,and find consistency between atomistic simulations and experiments,only by allowing laser energy to be transported away from the interaction region.This additional energy-loss pathway,which scales strongly with laser fluence,we attribute to hot electrons leaving the target on a timescale commensurate with melting。

摘要： This paper presents characteristic features of the explosion of thin flat foils for currents and pulse risetimes ranging from 8 kA at 350 ns to1000 kA at ～100 ns. Foils made of aluminum, copper, nickel, and titanium with thicknesses of 1–100 μm are tested. Various diagnostics inthe optical, UV, and x-ray spectral ranges are used to image the exploding foils from initial breakdown to complete destruction or pinching.It is shown that foil explosion is a complex process that depends on many factors, but features common to all foils are found that do notdepend on the parameters of the generators or, accordingly, on the energy deposited in the foil: for example, the breakdown of flat foils underdifferent conditions occurs at the edges of the foil. For the first time, the formation of a precursor over the central part of the foil is shown,which significantly changes the dynamics of the foil explosion.

摘要： This report reviews the researches for the middle and upper atmosphere in 2020-2022 by Chinese scientists.The report consists of five parts introducing primarily the results from the aspects of the development of infrastructure,the structure and composition,the climate and modeling,the dynamics for the middle and upper atmosphere,and Coupling between Stratosphere and Troposphere,respectively.

摘要： The authors regret that the word“trim/trims”has been wrongly used in the overall text,and instead the correct word“edge/edges”should have been used.The authors would like to apologise for any inconvenience caused.

摘要： 應用一種改進的分水嶺算法對集裝箱檢測圖像進行分割,并針對其中的過分割問題,提出基于Dynamics的合并準則,邊分割邊合并.利用LCIS的實際圖像進行分割實驗,得到滿意的結果.

摘要： 應用一種改進的分水嶺算法對集裝箱檢測圖像進行分割,并針對其中的過分割問題,提出基于Dynamics的合并準則,邊分割邊合并.利用LCIS的實際圖像進行分割實驗,得到滿意的結果.

摘要： 應用一種改進的分水嶺算法對集裝箱檢測圖像進行分割,并針對其中的過分割問題,提出基于Dynamics的合并準則,邊分割邊合并.利用LCIS的實際圖像進行分割實驗,得到滿意的結果.

摘要： 應用一種改進的分水嶺算法對集裝箱檢測圖像進行分割,并針對其中的過分割問題,提出基于Dynamics的合并準則,邊分割邊合并.利用LCIS的實際圖像進行分割實驗,得到滿意的結果.

摘要： 應用一種改進的分水嶺算法對集裝箱檢測圖像進行分割,并針對其中的過分割問題,提出基于Dynamics的合并準則,邊分割邊合并.利用LCIS的實際圖像進行分割實驗,得到滿意的結果.

摘要： 應用一種改進的分水嶺算法對集裝箱檢測圖像進行分割,并針對其中的過分割問題,提出基于Dynamics的合并準則,邊分割邊合并.利用LCIS的實際圖像進行分割實驗,得到滿意的結果.

摘要： 本發(fā)明涉及一種制備包含鎳、鋁、氧和硫且具有通式Ni

摘要： 本實用新型涉及一種Dynamic螺釘，包括萬向釘，外座，以及中間體；其中所述球狀部連接在所述螺紋部的端部；所述中間體容納部形成在所述冠狀部的內部，所述冠狀部的端部設置有所述多個凸起部，所述多個凸起部分別設置有鉤部；兩個夾持部連接所述插入部，所述球狀部容納部形成在所述插入部內部；所述兩個夾持部形成夾持固定桿的夾持空間；所述中間體設置在所述外座的所述中間體容納部內；所述萬向釘?shù)那驙畈吭O置在所述插入部的球狀部容納部內；所述萬向釘?shù)那驙畈靠稍谒銮驙畈咳菁{部內轉動，從而調節(jié)所述萬向釘?shù)墓潭ń嵌龋槐緦嵱眯滦偷腄ynamic螺釘采用萬向釘調節(jié)固定角度，零扭矩，固定更簡潔，方便調節(jié)，更高效，更短的手術時間。