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Study on viscosity mechanism of caffeine crystallization solutions Author links open overlay panel

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Particuology 2024年第8期91卷 341-350页

作者： Linjing Yu Min su School of Chemical Engineering Hebei University of TechnologyTianjin300130China

The solid-liquid viscous system formed by high viscosity crystallization solution impacts the flow and separation ***,it is very important to study the viscosity mechanism to improve viscosity and regulate crystallization,ensuring a seamless production ***,the viscosity of crystallization solution was taken as the measurement parameter of caffeine as a model *** investigated the viscosity mechanism of caffeine crystallization solutions by combining experiment and *** results indicated that the weak interactions between caffeine and water result in increased viscosity of the caffeine crystallization ***,caffeine crystals possess elongated needle-like shapes,featuring a substantial specific surface ***,there isπ-πstacking occurring between the(200)crystal face and(110)crystal face,effectively fostering coalescence of the crystals towards the radial side of the crystal along its elongated axis,resulting in a more viscous crystallization *** results contribute to comprehending the viscosity mechanism of crystal systems and provide theoretical foundation to enhance engineering efficiency in crystallization.

关键词： Crystallization Caffeine Viscosity mechanism Molecular simulation

Development of acoustic liner in aero engine: A review

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Science China(Technological Sciences) 2020年第12期63卷 2491-2504页

作者： MA XuQiang su ZhengTao Aviation Key Laboratory of Science and Technology on Materials and Application Research for Vibration and Noise Reduction AECC Beijing Institute of Aeronautical MaterialsBeijing 100095China

Noise reduction for aircraft engine has attracted great concern due to the strict noise control regulation nowadays. Conventional perforated sheet-over-honeycomb acoustic liners have been widely used to attenuate turbofan engine noise. To dampen the broadband noise and resist the harsh service conditions with high temperature and pressure in modern turbofan engine,new acoustic liner concepts are proposed and evaluated in the latest decade. In this review,available studies regarding the recent development of liners are gathered. The paper starts with the introduction of acoustic absorption mechanism of local-reacting and extended-reacting liners. The progress of novel passive liners(e.g.,mesh-cap liner,variable-depth liner,metal foam liner,hybrid liner,etc.) is summarized. Furthermore,adaptive liners with tunable geometry dimension or bias flow are illustrated in *** is also mentioned as a hot candidate in the next generation of acoustic liners. Finally,this review identifies benefits and some technical challenges with the goal of unveiling the potential of novel acoustic liner technologies in aero engine.

关键词： aero engine noise acoustic liner Helmholtz resonators composites

Distributed Optimal Control of Nonlinear Time-Delay System subject to Delayed Measurements and Communication Disruptions

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Journal of Systems Science & Complexity 2021年第4期34卷 1426-1437页

作者： su Baili DUAN Yuxing College of Engineering Qu/il Normal UniversityRizhao 276826China

This paper is focused on a distributed optimal control design for a class of nonlinear timedelay systems with delayed measurements and communication *** innovation lies in three *** distributed optimal control method which includes an optimal controller and a bounded controller is designed based on Lyapunov *** availability of data transmitted through the communication channel depends on a feasibility *** a sufficient condition to guarantee ultimate boundedness of the system is given based on appropriate *** significance of this paper is that this distributed optimal control method is applied to time-delay ***,a simulation example is given to verify the effectiveness of the proposed method.

关键词： Communication disruptions delayed measurements distributed optimal control nonlinear time-delay systems

Path A∞ algebras of positively graded quivers

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Frontiers of Mathematics in China 2018年第1期13卷 173-185页

作者： Hao su School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026 China

Let A be a path A∞-algebra over a positively graded quiver Q. We prove that the derived category of A is triangulated equivalent to the derived category of kQ, which is viewed as a DG algebra with trivial differentia... 详细信息

关键词： A∞-algebras Koszul dual DG-algebras

Numerical Simulation for the Optimization of Polygonal Pin Profiles in Friction Stir Welding of Aluminum

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Acta Metallurgica Sinica(English Letters) 2021年第8期34卷 1065-1078页

作者： Hao su Chuansong Wu MOE Key Lab for Liquid-Solid Structure Evolution and Materials Processing Institute of Materials JoiningShandong UniversityJinan 250061China

The tool with polygonal pin profile has been widely employed in friction stir welding(FSW) of aluminum, but there is hardly an effective optimization methodology existed as the thermomechanical characteristics affected by pins with various flats number have not been understood comprehensively. Therefore, the present work employs a 3-dimensional computational fluid dynamics(CFD) model to have an integrated observation of the FSW process with the effect of polygonal pin profiles. Both the heat generation modes due to contact friction at the tool–workpiece interface and volumetric viscous dissipation in the vicinity of the tool are considered. The model is utilized to give a quantitative analysis of the heat generation, temperature distribution, plastic material flow and welding loads during the FSW process for various tools with polygonal pin profiles, as well as a variety of shoulder diameters, welding speeds and tool rotation speeds. The calculated results of thermal cycles, tool torques and joint cross sections for some typical polygonal pins and welding parameters are all found to be compared well with the experimental ones, which demonstrates the feasibility and applicability of the present numerical model. Particularly, a methodology is developed for the optimization of the flats number by identifying the torque components in both parallel and vertical direction of the pin-side flat region. The results show that the optimized pin flats number increases with increasing tool rotation speed, while the influence of both welding speed and shoulder diameter can be supposed to be insignificant. Moreover, the dependability of the optimized results is also discussed by considering wear tendency and service life of the pin for multiple welding conditions.

关键词： Friction stir welding Polygonal pin Numerical simulation Optimization design Aluminum

Impact of tourism resource development based on low-carbon mode: a case study of Guizhou ethnic areas

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Ecological Processes 2019年第1期8卷 288-294页

作者： Jie su Guizhou University of Finance and Economics Huaxi University TownHuaxi DistrictGuiyang 550025GuizhouChina

Background:As environmental issues become increasingly prominent,the implementation of the low-carbon mode has become the trend of future economic *** implementation of a low-carbon mode in the tourism industry is conducive to the sustainable development of the industry,but at present the low-carbon development of China’s tourism industry still faces many problems,especially in ethnic areas where tourism is more ***:Taking Guizhou ethnic areas as an example,this study estimated the carbon emissions of the Guizhou tourism industry from 2011 to *** was found from the calculation of tourism consumption stripping coefficient that the total carbon emissions in 2011–2015 were 21.37,25.43,27.93,29.51,and 30.03 million tons,showing a rapid growth trend,in which the tourism accommodation catering industry accounted for a high ***:Guizhou’s carbon emissions are increasing year by year,and there are still many problems in realizing lowcarbon *** low-carbon tourism mode needs to be established from aspects of government,tourism enterprises,and *** rich tourism resources in minority areas should be fully utilized to realize the sustainable development of the tourism industry.

关键词： Low-carbon mode Tourism industry Guizhou

Fluctuations of deformed Nigner random matrices

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Frontiers of Mathematics in China 2013年第3期8卷 609-641页

作者： Zhonggen su Department of Mathematics Zhejiang University Hangzhou 310027 China

Let Xn be a standard real symmetric （complex Hermitian） Wigner matrix, Y1,Y2,...,Yn a sequence of independent real random variables independent of Xn. Consider the deformed Wigner matrix Hn,a = n^（-1/2）Xn ＋ n^（-a/2）diag（y1,...,yn）, where 0 〈 a 〈 1. It is well known that the average spectral distribution is the classical Wigner semicircle law, i.e., the Stieltjes transform mn,a（z） converges in probability to the corresponding Stieltjes transform rn（z）. In this paper, we shall give the asymptotic estimate for the expectation Emn,a （z） and variance Var（mn,a （z））, and establish the central limit theorem for linear statistics with sufficiently regular test function. A basic tool in the study is Stein＇s equation and its generalization which naturally leads to a certain recursive equation.

关键词： Asymptotic expansion deformed Wigner matrice Gaussianfluctuation linear statistics Stein's equation

Free energy fluctuations for a mixture of directed polymers

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Science China Mathematics 2017年第3期60卷 511-528页

作者： su ZhongGen Department of Mathematics Zhejiang University Hangzhou 310027 China

We study the free energy fluctuations for a mixture of directed polymers, which was first introduced by Borodin et al. （2015） to investigate the limiting distribution of a stationary Kaxdar-Parisi-Zhang （KPZ） equation. The main results consist of both the law of large numbers and the asymptotic fluctuation for the free energy as the model size tends to infinity. In particular, we find the explicit values （which may depend on model parameters） of normalizing constants in the fluctuation. This shows that such a mixture model is in the KPZ university class.

关键词： free energy KPZ universality class log-Gamma directed polymer O'Connell-Yor semi-discretedirected polymer Tracy-Widom law

Strategy of Development of Rare Earth Industry in China

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Journal of Rare Earths 2004年第z1期22卷 274-281页

作者： su Wenqing School of Management Xi'' an Jiaotong University Xi'' an 710049 China

This work introduced the current situation of the development of domestic and foreign rare earths (RE) industry, discussed the strategic position of RE industry in China, analyzed the problems existing in the course of RE industry development, made strategic thought about the transference from resource advantage to economic advantage, and put forward strategic suggestions about the development of RE industry in our country.

关键词： industrial development strategy rare earths