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Theoretical study on bubble dynamics under hybrid-boundary and multi-bubble conditions using the unified equation

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Science China(Physics,Mechanics & Astronomy) 2023年第12期66卷 142-157页

作者： A-Man Zhang shi-min li Pu Cui Shuai li Yun-Long liu College of shipbuilding Engineering Harbin Engineering UniversityHarbin 150001China Nanhai Institute of Harbin Engineering University Sanya 572024China

This paper aims to use the unified bubble dynamics equation to investigate bubble behavior in complex scenarios involving hybrid free surface/wall boundaries and interactions between multiple *** effect of singularity movement on the unified equation’s form is analyzed after deriving the bubble pulsation equation using a moving point source and a dipole,followed by discussions on the effect of migration compressibility-related terms on the bubble *** addition,the present study accounts for the impact of hybrid boundaries,including crossed and parallel boundaries,by introducing a finite number of mirror bubbles for the former and an infinite number of mirror bubbles for the *** bubble experiments and numerical simulation are conducted to validate the present *** application of the unified equation in multi-bubble interactions is exemplified by computing a spherical bubble array containing more than 100 uniformly distributed cavitation bubbles under different boundary *** bubble cluster-induced pressure peak can reach nearly two times or even higher than that of an individual bubble,highlighting the damage potential caused by cavitation bubble clusters.

关键词： bubble dynamics multiphase flows cavitation

Theoretical analysis of the surface temperature regulation of an infrared false target subjected to periodical ambient conditions

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Defence Technology（防务技术） 2016年第5期12卷 360-366页

作者： shi-min li Hong YE Qi-zhao liN Department of Thermal Science and Energy Engineering University of Science and Technology of China

Infrared false target is an important mean to induce the infrared-guided weapons,and the key issue is how to keep the surface temperature of the infrared false target to be the same as that of the object to be ***-dimensional heat transfer models of a metal plate and imitative material were established to explore the influences of the thermophysical properties of imitative material on the surface temperature difference（STD） between the metal plate and imitative material which were subjected to periodical ambient *** is elucidated that the STD is determined by the imitative material’s dimensionless thickness（dim*,） and the thermal inertia(Pim).When dim* is above 1.0,the STD is invariable as long as Pim is a *** if the dimensionless thickness of metal plate（d,m*） is also larger than 1.0,the STD approaches to zero as long as Pimis the same as the thermal inertia of metal plate（Pm）.When dim* is between 0.08 and 1,the STD varies irregularly with Pim and dim*.However,if dm* is also in the range of 0.08-1,the STD approaches to zero on condition that Pim=Pm and dim*= dm*.If dim*,is below 0.08,the STD is unchanged when Pimdim* is a *** if dm* is also less than 0.08,the STD approaches to zero as long as Pimdim* = Pmdm*.Furthermore,an applicationoriented discussion indicates that the imitative material can be both light and thin via the application of the phase change material with a preset STD because of its high specific heat capacity during the phase transition process.

关键词： Infrared false target Surface temperature Periodical ambient conditions Thermal inertia Dimensionless thickness

A linear complementarity model for multibody systems with frictional unilateral and bilateral constraints

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Acta Mechanica Sinica 2011年第4期27卷 587-592页

作者： Hai-Ping Gao Qi Wang shi-min Wang li Fu Department of dynamics and control Beihang University 100191 Beijing China

The Lagrange-I equations and measure differential equations for multibody systems with unilateral and bilateral constraints are constructed. For bilateral constraints, frictional forces and their impulses contain the products of the filled-in relay function induced by Coulomb friction and the absolute values of normal constraint reactions. With the time-stepping impulse-velocity scheme, the measure differential equations are discretized. The equations of horizontal linear complementarity problems （HLCPs）, which are used to compute the impulses, are constructed by decomposing the absolute function and the filled-in relay function. These HLCP equations degenerate into equations of LCPs for frictional unilateral constraints, or HLCPs for frictional bilateral constraints. Finally, a numerical simulation for multibody systems with both unilateral and bilateral constraints is presented.

关键词： Coulomb friction Bilateral constraint Unilat-eral constraint - Horizontal linear complementarity problem(HLCP) Time-stepping impulse-velocity algorithm

Effect of a rigid structure on the dynamics of a bubble beneath the free surface

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Theoretical & Applied Mechanics Letters 2021年第6期11卷 355-361页

作者： shi-min li A-Man Zhang Nian-Nian liu College of shipbuilding Engineering Harbin Engineering UniversityHarbin 150001China

The coupling effect between a pulsating bubble and a free surface near a rigid structure is a complicated physical *** this study,the evolution of an underwater explosion bubble and the free surface near a rigid structure is modeled by the boundary integral *** approach of“double-node method”is used to maintain the stability of fluid-structure junction in the simulations,and meshes on the free surface and the structure are transformed to an open domain to ensure the calculation accuracy and *** are conducted against an underwater explosion experiment near a rigid *** a result,the simulations trace the jetting behavior of the bubble and the rise of the free ***,the bubble migration and the height of the free surface for different structure draughts are analyzed.

关键词： Underwater explosion Bubble dynamics Boundary integral method

Synthesis and Characterization of Layered Co_2(OH)_3(CH_3COO)·H_2O

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Chemical Research in Chinese Universities 2011年第6期27卷 910-914页

作者： ZHENG De-shan WANG Yan-zhong shi li-min SUN Si-xiu School of Materials and Chemical Engineering Xi＇an Technological University Xi＇an 710032 P. R. China School of Chemistry and Chemical Engineering Shandong University Jinan 250100 P. R. China

Layered hydroxide metal acetate Co2（OH）3（CH3COO）·H2O with an interlayer spacing of 1.282 nm has been synthesized by a novel method which is employed in ethanol-aqueous mixed solvents media. Experiment results show that the purity of the product by the modified method is higher compared with that by the previous methods. A complete characterization of the as-prepared samples was performed by means of X-ray powder diffraction, IR spectroscopy, scanning electron microscope, as well as magnetic measurement. The facile and effective approach for the preparation of this compound in this study is very interesting and important because it has wide application in the field of anionic exchange reaction for the synthesis of hybrid organic-inorganic compounds.

关键词： Anionic exchange reaction Hybrid organic-inorganic compound Layered hydroxide cobalt acetate Magnetic property

Interactions between a central bubble and a surrounding bubble cluster

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Theoretical & Applied Mechanics Letters 2023年第3期13卷 216-221页

The interaction of multiple bubbles is a complex physical problem.A simplified case of multiple bubbles is studied theoretically with a bubble located at the center of a circular bubble *** bubbles in the cluster are equally spaced and own the same initial conditions as the central *** unified theory for bubble dynamics[35]is applied to model the interaction between the central bubble and the circular bubble *** account for the effect of the propagation time of pressure waves,the emission source of the wave is obtained by interpolating the physical information on the time *** underwater explosion experiment with two bubbles of different scales is used to validate the theoretical *** effect of the bubble cluster with a variation in scale on the pulsation characteristics of the central bubble is studied.

关键词： Bubble dynamics Bubble cluster

Effect of Zr Content on Formation and Optical Properties of the Layered PbZrxTi1-xO3 Films

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Chinese Physics Letters 2020年第2期37卷 43-46页

作者： Yang-Yang Xu Yu Wang Ai-Yun liu Wang-Zhou shi Gu-Jin Hu shi-min li Hui-Yong Deng Ning Dai Department of Physics College of Mathematics and ScienceShanghai Normal UniversityShanghai 200234 National Laboratory for Infrared Physics Shanghai Institute of Technical PhysicsChinese Academy of SciencesShanghai 200083

PbZrxTi1-xO3(PZT)fims are fabricated on F-doped tin oxide(FTO)substrates using chemical solutions containing PVP polymer and rapid thermal annealing *** dependence of the layered PZT multilayer formation and their optical properties on the Zr content x are *** is found that all the PZT films are crystallized and exhibit 110-preferred *** x varies in the region of 0-0.8,the PZT films display lamellar structures,and a high reflection band occurs in each optical reflectance spectrum ***,those PZT fikms with Zr/Ti atomic ratio of 35/65-65/35 show clearly layered cross-sectional morphologies arranged alternatively by porous and dense PZT layers,and have a peak optical reflectivity of>70%and a band width of>45 *** obtain the optimal Bragg reflection performance of the PZT multilayers,the Zr content should be selected in the range of 0.35-0.65.

关键词： sectional reflectivity films

Local excision of ciliary body tumors： a long-term prospective cohort study in China

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Chinese Medical Journal 2008年第21期121卷 2152-2156页

作者： WEI Wen-bin YANG Wen-li HU shi-min li Bin Ophthalmology and Visual Science Key Laboratory Beijing Tongren Eye Center Beijing Tongren HospitaL Capital Medical University Beijing 100730 China

Background Ciliary body tumors are usually difficult to diagnose and treat in early stages. However, treatment of such tumors has trended toward ocular conservation instead of enucleation. Local excision of ciliary body tumors has become effective with the development of the modern vitrectomy, but long-term outcomes are still not clear. Therefore, we reported the outcome of locally excised ciliary body tumors after long-term follow-up. Methods Twenty-two patients （22 eyes）, who had been diagnosed with ciliary body tumors in Beijing Tongren Hospital from January 1996 to June 2001, were enrolled in this prospective cohort study. Localized lamellar sclera-ciliary excisions were performed. In some cases, vitrectomies, scleral graft transplantations, and further excisions of the anterior choroid were performed. Diagnoses were confirmed by histopathologic examination. Patients were followed from five to eleven years after surgery. Their visual acuity, intraocular pressure and local recurrence were recorded with descriptive percentages. Results After surgery, all patients maintained normal eyeball appearances. Six patients maintained circular pupils. The final best corrected visual acuities （BCVA） varied from 0.02-1.00, including 18 patients （81.82%） who had BCVA equal to or better than that before surgery. Fifteen patients （68.18%） had BCVA better than 0.3. Only two patients had intraocular pressure （lOP） of less than 10 mmHg and the other patients maintained normal lOP. Nine cases （40.91%） were given confirmed diagnosis of malignant melanoma, four （18.18%） of melanocytoma, six （27.27%） of nonpigmented ciliary epithelial adenoma, two （9.09%） of neurofibroma, and one （4.55%） of neurinoma. Twenty patients （90.91%） had no recurrence during the follow-up period. In one case melanocytoma recurred seven years after surgery and enucleation was performed. One patient, whose operation removed a malignant melanoma with a diameter of 16 mm, died of hepatic metastasis five years

关键词： ciliary body tumor local excision prospective cohort study

Joint Feature Encoding and Task Alignment Mechanism for Emotion-Cause Pair Extraction

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Computers, Materials & Continua 2025年第1期82卷 1069-1086页

作者： shi li Didi Sun College of Computer and Control Engineering Northeast Forestry UniversityHarbin150040China

With the rapid expansion of social media,analyzing emotions and their causes in texts has gained significant ***-cause pair extraction enables the identification of causal relationships between emotions and their triggers within a text,facilitating a deeper understanding of expressed sentiments and their underlying *** comprehension is crucial for making informed strategic decisions in various business and societal ***,recent research approaches employing multi-task learning frameworks for modeling often face challenges such as the inability to simultaneouslymodel extracted features and their interactions,or inconsistencies in label prediction between emotion-cause pair extraction and independent assistant tasks like emotion and cause *** address these issues,this study proposes an emotion-cause pair extraction methodology that incorporates joint feature encoding and task alignment *** model consists of two primary components:First,joint feature encoding simultaneously generates features for emotion-cause pairs and clauses,enhancing feature interactions between emotion clauses,cause clauses,and emotion-cause ***,the task alignment technique is applied to reduce the labeling distance between emotion-cause pair extraction and the two assistant tasks,capturing deep semantic information interactions among *** proposed method is evaluated on a Chinese benchmark corpus using 10-fold cross-validation,assessing key performance metrics such as precision,recall,and F1 *** results demonstrate that the model achieves an F1 score of 76.05%,surpassing the state-of-the-art by 1.03%.The proposed model exhibits significant improvements in emotion-cause pair extraction(ECPE)and cause extraction(CE)compared to existing methods,validating its *** research introduces a novel approach based on joint feature encoding and task alignment mechanisms,contributing to advancements in emotion-c

关键词： Emotion-cause pair extraction interactive information enhancement joint feature encoding label consistency task alignment mechanisms