检索结果-南通市图书馆

同方期刊数据库

Lanthanide mechanoluminescence

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2018年第1期36卷 1-41页

作者： Jean-Claude G.bünzli ka-Leung Wong Institute of Chemical Sciences and Engineering Swiss Federal Institute of Technology Lausanne (EPFL) CH-1015 Lausanne Switzerland Department of Chemistry Hong Kong Baptist University Kowloon Tong Hong Kong China

Mechanoluminescence （ML） is the emission of light consecutive to a mechanical force or stress imposed to a crystalline material. Many inorganic and organic compounds present this phenomenon that is known for over 400 years. Lanthanide and uranyl salts were among the first substances investigated for this property. Mechanoluminescence, also referred to as triboluminescence, is often considered as being a badly understood phenomenon. In fact it is because of two main reasons. Firstly, a variety of different mechanical stresses, from simple rubbing, to applied pressure, crushing, impact of a weight, ultrasound, laser-generated shock wave, crystallization, dissolution of crystals, or even wind can trigger it. Secondly, ML is very sensitive to the purity and morphology of the sample： in inorganic compounds, generation of traps by doping ＂impurities＂（e.g. lanthanide ions） is responsible for light emission so that the exact composition of the sample has to be known to a very detailed level; for chelates, the crystallization conditions are crucial since they often generate extended networks of weak interactions that are instrumental in triggering ML when they are broken. In fact mechanisms of ML are relatively well known and theories and models often reproduce very well the experiments. Additionally, practical applications are at hand, for example stress, crack, and impact sensors based on SrAI204：Eu11 or Et3NH[Eu（dbm）4] are used to test structures and materials as diverse as road bridges, reinforced concrete elements, pressur- ized containers or airplane wings and to image the propagation of cracks or stress distribution. Military and security applications involve detecting the passage of vehicle or soldiers and producing counter- feiting inks while more joyful applications are luminous balls, wrapping papers and adhesive tapes. Not only bulk materials, but micro- and nanoparticles feature mechanoluminescent properties and single particle manipulation under an AFM allows

关键词： MechanoluminescenceRare earthsStress sensorsPressure sensorsImpact sensors

Tribonacci Partition Formulas Modulo m

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2010年第3期26卷 465-476页

作者： Ji■í KLA■ka Institute of Mathematics Brno University of Technology

Each Tribonacci sequence starting with an arbitrary triple of integers is periodic modulo m for any modulus m 〉 1. For a given m, the mapping between the set S of all m^3 triples of initial values and the set of their coresponding periods define a partition of the set S. In this paper we shall investigate some basic questions related to these partitions from the point of view of enumerative combinatorics.

关键词： Tribonacci sequence modular periodicity partition formulas

Computational design of structured chemical products

在线全文

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2021年第5期15卷 1033-1049页

作者： Faheem Mushtaq Xiang Zhang ka Y.Fung ka M.Ng Department of Chemical and biological Engineering The Hong Kong University of Science and TechnologyHong KongChina

In chemical product design,the aim is to formulate a product with desired *** and internal product structure are two key drivers of product performance with direct impact on the mechanical,electrical,and thermal ***,there is a keen interest in elucidating the dependence of product performance on ingredients,structure,and the manufacturing process to form the *** of product structure,particularly microstructure,is an intrinsically complex problem that involves different phases of different physicochemical properties,mass fraction,morphology,size distribution,and ***,computational methods have emerged that assist systematic microstructure quantification and *** objective of this paper is to review these computational methods and to show how these methods as well as other developments in product design can work seamlessly in a proposed performance,ingredients,structure,and manufacturing process framework for the design of structured chemical *** begins with the desired target properties and key *** is followed by computation for microstructure and then selection of processing steps to realize this *** framework is illustrated with the design of nanodielectric and die attach adhesive products.

关键词： product design performance ingredients structure manufacturing process framework structured chemical products microstructure design

All-parameters Rayleigh wave inversion

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2021年第2期20卷 517-534页

作者： Xiao-Hui Yang ka-Veng Yuen State Key Laboratory of Internet of Things for Smart City and Department of Civil and Environmental Engineering University of MacaoMacao 999078China

Since S-wave velocity of the subsurface is an important parameter in near surface applications,many studies have been conducted for its *** the various methods that use surface waves or body waves,Rayleigh wave inversion is the most *** practice,the densities and P-wave velocities of different layers are usually assumed to be known to avoid ill-posed problems,as they have less influence on the dispersion ***,improper assignment of these two groups of parameters leads to inaccurate estimation of the S-wave velocity *** order to address this problem,the all-parameters Rayleigh wave inversion strategy is proposed in which the S-wave velocities,layer thicknesses,densities and P-wave velocities of different layers are included as the unknown parameters for ***,the transitional Markov Chain Monte Carlo(TMCMC)algorithm is applied for the implementation of all-parameters Rayleigh wave *** simulated example and two real-test applications are demonstrated to verify the capability of the proposed method in the estimation of the S-wave velocity profile,the densities and the P-wave ***,it is verified that the proposed method achieved more accurate S-wave velocity profile estimation than the traditional approach.

关键词： all-parameters Rayleigh wave inversion bayesian S-wave velocity profile TMCMC algorithm uncertainty quantification

The Most General Corrdinate Transformation between the Hydrogen Atom and Harmonic Oscillator in Arbitrary Dimensions

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1997年第10期14卷 721-723页

作者： SU ka-lin Department of Physics Yueyang Normal CollegeYueyang 414000

In this paper,we find out the most general coordinate transformation between a d-dimensional hydrogen atom and a D-dimensional harmonic oscillator by means of the SU(1,l)*** other words,the generalized Kustaanheimo-St... 详细信息

关键词： algebra Transformation coordinate

bayesian Rayleigh wave inversion with an unknown number of layers

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2020年第4期19卷 875-886页

作者： ka-Veng Yuen Xiao-Hui Yang State Key Laboratory of Internet of Things for Smart City and Department of Civil and Environmental Engineering University of Macao999078MacaoChina

Surface wave methods have received much attention due to their efficient, flexible and convenient characteristics. However, there are still critical issues regarding a key step in surface wave inversion. In most existing methods, the number of layers is assumed to be known prior to the process of inversion. However, improper assignment of this parameter leads to erroneous inversion results. A bayesian nonparametric method for Rayleigh wave inversion is proposed herein to address this problem. In this method, each model class represents a particular number of layers with unknown S-wave velocity and thickness of each layer. As a result, determination of the number of layers is equivalent to selection of the most applicable model class. Regarding each model class, the optimization search of S-wave velocity and thickness of each layer is implemented by using a genetic algorithm. Then, each model class is assessed in view of its efficiency under the bayesian framework and the most efficient class is selected. Simulated and actual examples verify that the proposed bayesian nonparametric approach is reliable and efficient for Rayleigh wave inversion, especially for its capability to determine the number of layers.

关键词： bayesian model class selection generalized r/t coefficients algorithm genetic algorithm inversion of Rayleigh wave number of layers

Modeling of environmental influence in structural health assessment for reinforced concrete buildings

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2010年第2期9卷 295-306页

作者： ka-Veng Yuen Sin-Chi Kuok Department of Civil and Environmental Engineering Univeristy of Macao

One branch of structural health monitoring (SHM) utilizes dynamic response measurements to assess the structural integrity of civil infrastructures. In particular,modal frequency is a widely adopted indicator for structural damage since its square is proportional to structural stiffness. However,it has been demonstrated in various SHM projects that this indicator is substantially affected by fluctuating environmental conditions. In order to provide reliable and consistent information on the health status of the monitored structures,it is necessary to develop a method to filter this interference. This study attempts to model and quantify the environmental influence on the modal frequencies of reinforced concrete buildings. Daily structural response measurements of a twenty-two story reinforced concrete building were collected and analyzed over a one-year period. The bayesian spectral density approach was utilized to identify the modal frequencies of this building and it was clearly seen that the temperature and humidity fluctuation induced notable variations. A mathematical model was developed to quantify the environmental effects and model complexity was taken into consideration. based on a Timoshenko beam model,the full model class was constructed and other reduced-order model class candidates were obtained. Then,the bayesian modal class selection approach was employed to select the one with the most suitable complexity. The proposed model successfully characterizes the environmental influence on the modal frequencies. Furthermore,the estimated uncertainty of the model parameters allows for assessment of the reliability of the prediction. This study not only improves the understanding about the monitored structure,but also establishes a systematic approach for reliable health assessment of reinforced concrete buildings.

关键词： bayesian inference model selection reinforced concrete building structural health monitoring temperature and humidity effects Timoshenko beam

Optimal Design of Splitters Attached to Turbo blower Impeller by RSM

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2012年第3期21卷 215-222页

作者： Choon-Man Jang ka-Ram Choi Environmental Engineering Research Division Korea Institute of Construction Technology

This paper describes the optimization of the impeller having splitters for a turbo *** design variables,chord of splitter and pitch of splitter,are introduced to enhance the blower *** pressure and ef-ficiency are selected as an object function,and the optimization of the blower impeller is performed by a response surface method (RSM).Three-dimensional Navier-Stokes equations are introduced to analyze the internal flow of the blower and to find the value of the object function for each *** the shape optimization of the splitters attached to the impeller in the turbo blower,pressure and efficiency at the design flow condition are suc-cessively increased by 5.9 percent and 17.9 percent respectively based on the reference *** higher blower efficiency obtained by optimization of impeller having splitters is mainly caused by reducing the number of im-peller blades and optimal design of splitters in the blade passage while pressure increase keeps almost the same with the reference *** the object function of pressure,pressure increase is obtained at the design and off-design conditions while efficiency keeps higher compared to the reference *** enhancement of blow-er performance is due to the reduction of reverse and circulation flows in the blade passage.

关键词： Turbo blower Splitter Numerical Simulation Optimal Design Pressure Response Surface Method

On predicting mantle mushroom plumes

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2011年第2期2卷 223-235,235+233-234页

作者： ka-Kheng Tan Rex b. Thorpe Zhidan Zhao Global Environment Centre HELP University College BZ-2 Pusat Bandar Damansara 50490 Kuala Lumpur Malaysia Department of Chemical and Process Engineering University of Surrey Guildford GU2 7XH U School of Earth Sciences and Resources China University of Geosciences Beijing 100083 China

This study investigates the mechanism of formation of convection plumes of mushroom shape in sub-solidus mantle and their prediction. The seismic-tomographic images of columnar structures of several hundreds kilometers in diameter have been reported by several researchers, while the much cherished mushroom-shaped plume heads could only be found in computational geodynamics （CGD） models and simple small-scale laboratory analogue simulations. Our theory of transient instability shows that the formation of convection plumes is preceded by the onset of convection caused by unsteady-state heat conduction at the boundaries, from which filamentous plumes first appear. The plumes generated at the Core Mantle boundary （CMb） and lithosphere rising and falling through the mantle have been pre- dicted simply with our theory for various heat fluxes and viscosities, which still remain uncertain amongst geoscientists. The sizes of mushroom plumes in the sub-solidus mantle caused by heat fluxes of 20 and 120 mW/m2 at the CMb are found to be 1842 km and 1173 km with critical times over 825 Myr and 334 Myr respectively. They are comparable to some large continental flood basalt provinces, and they number between 17 and 41. The thickness of the thermal boundary layers at the CMb from which convection plumes evolved are found to be 652 km and 415 km for 20 and 120 mW/m^2 respectively. Top cooling may produce plunging plumes of diameter of 585 km and at least 195 Myr old. The number of cold plumes is estimated to be 569, which has not been observed by seismic tomograpby

关键词： Mantle mushroom plumesSizes Critical times Transient Reynoldsnumber