Simulation algorithm for spiral case structure in hydropower station

In this study, the damage-plasticity model for concrete that was verified by the model experiment was used to calculate the damage to a spiral case structure based on the damage mechanics theory. The concrete structure surrounding the spiral case was simulated with a three-dimensional finite element model. Then, the distribution and evolution of the structural damage were studied. Based on investigation of the change of gap openings between the steel liner and concrete structure, the impact of the non-uniform variation of gaps on the load-beating ratio between the steel liner and concrete structure was analyzed. The comparison of calculated results of the simplified and simulation algorithms shows that the simulation algorithm is a feasible option for the calculation of spiral case structures. In addition, the shell-spring model was introduced for optimization analysis, and the results were reasonable.

COMPUTER SIMULATION OF STRUCTURE OF La-LaCl_3-KCl MELT

The structure of the La-LaCl_3-KCl molten system at 1223K has been investigated by computer simulation using Monte Carlo method.The partial radial distribution functions of some ion pair as well as the potential and internal energy of the system at 1223K have been calculated.The results implies that about 50% of La(Ⅲ)is six coordinated and LaCl_4^(2-) tetrahedron is the predominant configuration for La(Ⅱ). It is also concluded that the distribution of free space in the molten system is not uniform.There exist many fissures and empty holes in the molten salt.

Computer Simulation of the Structure and Propertiesof Nanocrystals

This paper provides a computer modeling method for the study of nanocrystals. Structural features,such as the boundary component proportion, the reduced density proportion, the excess lattice parameter, and the radial distribution function, have been atomistically simulated. The energy and elastic properties also have been investigated. Simulation results indicate that the structure of grain boundaries in nanocrystals is different from those of the amorphous and the gas, or rather, it is a special structure with some degree of short-range order. Moreover, the structure of crystallites is not entirely the same as that in the perfect crystal lattice. The present simulation method may become one of the foundations of the theoretical study of nanocrystals.

A New Simulation of Track Structure of Low-Energy Electrons in Liquid Water:Considering the Condensed-Phase Effect on Electron Elastic Scattering

A new Monte Carlo simulation of the track structure of low-energy electrons （〈10keV） in liquid water is presented. The feature of the simulation is taken into consideration of the condensed-phase effect of liquid water on electron elastic scattering with the use of the Champion model, while the dielectric response formalism incorporating the optical-data model developed by Emfietzoglou et al. is applied for calculating the electron inelastic scattering. The spatial distributions of energy deposition and inelastic scattering events of low-energy electrons with different primary energies in liquid water are calculated and compared with other theoretical evaluations. The present work shows that the condensed-phase effect of liquid water on electron elastic scattering may be of the influence on the fraction of absorbed energy and distribution of inelastic scattering events at lower primary energies, which also indicate potential effects on the DNA damage induced by low-energy electrons.

Wind tunnel simulation of wind loading on a solid structure of revolution

The wind tunnel simulations of wind loading on a solid structure of revolution with one smooth and five rough surfaces were conducted using wind tunnel tests. Timemean and fluctuating pressure distributions on the surface were obtained, and the relationships between the roughness Reynolds number and pressure distributions were analyzed and discussed. The results show that increasing the surface roughness can significantly affect the pressure distribution, and the roughness Reynolds numbers play an important role in the change of flow patterns. The three flow patterns of subcritical, critical and supercritical flows can be classified based on the changing patterns of both the mean and the fluctuating pressure distributions. The present study suggests that the wind tunnel results obtained in the supercritical pattern reflect more closely those of full-scale solid structure of revolution at the designed wind speed.

Numerical simulation of vortex-induced drag of elastic swimmer models

We present numerical simulations of simplified models for swimming organisms or robots, using chordwise flexible elastic plates. We focus on the tip vortices originating from three-dimensional effects due to the finite span of the plate. These effects play an important role when predicting the swimmer＇s cruising velocity, since they contribute significantly to the drag force. First we simulate swimmers with rectangular plates of different aspect ratios and compare the results with a recent experimental study. Then we consider plates with expanding and contracting shapes. We find the cruising velocity of the contracting swimmer to be higher than the rectangular one, which in turn is higher than the expanding one. We provide some evidence that this result is due to the tip vortices interacting differently with the swimmer.

An ultrasound simulation method for carotid arteries with a wall structure of three membranes

Ultrasound simulation for carotid arteries is helpful to the performance assessments of vessel wall detection and signal processing methods by using ultrasound techniques. An ul- trasound simulation method of carotid artery wall with a three-membrane structure is proposed in present study. According to the ultrasound speckle distributions varying with the shapes and densities of scatterer distributions, as well as the statistic results of the clinical images, the parameters of distributions, densities and intensities of scatterers for different kinds of tissues in the carotid artery phantoms are determined. Each region is acoustically characterized using FIELD II software to produce the radio frequency echo signals, from which ultrasound images are derived. The results based on 30 simulations show that the echo distributions of the intimae, mediae, adventitias and blood are consistent with the clinical ones. Moreover, compared with the results from the central frequency of 8 MHz, the mean measurements for thicknesses of the intima, media and adventitia membranes, as well as the lumen diameter from the simulation images based on 12 MHz are the same as the preset ones, and the maximum relative errors are the 4.01%, 1.25%, 0.04% and 0.15%, respectively. The simulation under this condition is more realistic.

Design of MEMS C-Band Microstrip Antenna Array Based on High-Resistance Silicon for Intelligent Ammunition

In recent years, microstrip antennas have been more widely applied in satellite communications, mobile phones, unmanned aerial vehicle （UAV）, and weapons. A micro-electro-mechanical systems-based （MEMS-based） high-resistance silicon C-band microstrip antenna array has been designed for the intelligent ammunition. The center frequency is 4.5 GHz. A cavity has been designed in substrate to reduce the dielectric constant of silicon and high-resistance silicon has been used as the material of substrate to improve the gain of antenna. It is very easy to be manufactured by using MEMS technology because of the improved structure of the antenna. The results show that the gain of the antenna is 8 dB and voltage standing wave ratio （VSWR） is less than 2 by the analysis and simulation in high freauencv structure simulator （HFSS）.

Reduced technique for modeling electromagnetic immunity on braid shielding cable bundles

In this paper, an efficient multi-conductor simplification technique is proposed to model the electromagnetic immunity on cable bundles within a braid shielding structure over a large frequency range. By grouping together the conductors based on the knowledge of Z-Smith chart, the required computation time is markedly reduced and the complexity of modeling the completely shielding cable bundles is significantly simplified with a good accuracy. After a brief description of the immunity problems in shielding structure, a six-phase procedure is detailed to generate the geometrical characteristics of the reduced cable bundles. Numerical simulation is carried out by using a commercial software CST to validate the efficiency and advantages of the proposed approach. The research addressed in this paper is considered as a simplified modeling technique for the electromagnetic immunity within a shielding structure.

Ecological security pattern-based simulation for land use structure change:a case study in Ezhou City,China

The ecological environment quality is an important constraint and an optimization objective for land resource allocation.Integrating ecological service value(ESV)accounting and ecological security pattern(ESP)delineation,and combining with the land use structure of 2004/2010/2016 in Ezhou City,this research laid out the urban ESP based on ESV with Net Primary Productivity(NPP),and made it as the main influence factor to simulate land use structure in 2022.The results indicated that:1)The water body has the biggest contribution to ESV,while the construction land has the minimum;2)91 ecological corridors are extracted,of which 28 were important ecological corridors;there were 36 ecological nodes extracted,including 17 important nodes;3)According to ESV,Ezhou City was divided into four security zones.The area of ecological restoration zone was the largest,and human activity core zone area was the smallest;4)In the no ESP protection scenarios and ESP protection scenarios separately,the net increase area of construction land is from 868.5 hm^(2) to 52.74 hm^(2) in the ecological core protection area;the construction land in the human activity core area has been increased by 2342.31 hm^(2) in protected scene,766.23 hm^(2) more than that of the unprotected scene.The results show that the division of security zones promoted the relocation of construction land from ecological protection core zone to human activity core zone,which can protect the ecological environment effectively,and the ESP-based simulation can provide the decision-making reference to coordinate the relationship of regional land resource allocation and the ecological environment protection.

Thermal analysis and optimization of the EAST ICRH antenna

The ion cyclotron resonance of frequency heating（ICRH） plays an important role in plasma heating.Two ICRH antennas were designed and applied on the EAST tokamak.In order to meet the requirement imposed by high-power and long-pulse operation of EAST in the future,an active cooling system is mandatory to be designed to remove the heat load deposited on the components.Thermal analyses for high heat-load components have been carried out,which presented clear temperature distribution on each component and provided the reference data to do the optimization.Meanwhile,heat pipes were designed to satisfy the high requirement imposed by a Faraday shield and lateral limiter.

Effects of Internal Relaxation under Inplane Strain on the Structural,Electronic and Optical Properties of Perovskite BaZrO3

We present the specific ab-initio calculations that detail the variations of perovskite BaZrO3 caused by in-plane strain. Specifically, the internal relaxation, which was not captured in the widely used biaxial strain model, was included in a complementary manner to lattice relaxation. Density functional theory as well as a hybrid functional method based on a plane wave basis set was employed to calculate the lattice structure, elastic constants, electronic properties and optical properties of perovskite BaZrO3. The lattice parameter c exhibited a clear linear dependence on the imposed in-plane strain, but the Poisson＇s ratio caused by internal relaxation was smaller than the elastic deformation, indicating an ＂inelastic＂ or ＂plastic＂ relaxation manner caused by the introduction of internal relaxation. As a result, the related electronic and optical properties of perovskite BaZrO3 were also strongly affected by the in-plane strain, which revealed an effective way to adjust the properties of perovskite BaZrO3 via internal relaxation.

A DWT Power Spectrum Analysis of PSCz Galaxies

The power spectrum estimator based on the Discrete Wavelet Transfor- mation (DWT) is applied to detect the clustering power in the IRAS Point Source Catalog Redshift Survey (PSCz). Comparison with mock samples extracted from N-body simulation shows that the DWT power spectrum estimator could provide a robust measurement of banded fluctuation power over a range of wavenumbers 0.1 ~ 2.0hMpc-1. We have fitted three typical CDM models (SCDM, τCDM and CDM) using the Peacock-Dodds formula including non-linear evolution and redshift distortion. We find that, our results are in good agreement with other statistical measurements of the PSCz.

Vertical Profile Comparison of Aerosol and Cloud Optical Properties in Dominated Dust and Smoke Regions over Africa Based on Space-Based Lidar

This study evaluates the vertical profiles of aerosol and cloud optical properties in 40 dominated dust and smoke regions in Western-Northern Africa (WNA) and Central-Southern Africa (CSA), respectively, from the surface to 10km and from 2008 to 2011 based on LIVAS (LIdar climatology of Vertical Aerosol Structure for space-based lidar simulation studies). Aerosol extinction (AE), aerosol backscatter (AB), and aerosol depolarization (AD) generally increase from the surface to 1.2 km and decrease from 1.2 km to the upper layers in both WNA and CSA. AE and AB in CSA (maximum of 0.13 km-1, 0.14 km-1, 0.0021 km-1‧sr-1, 0.0033 km-1‧sr-1) are higher than in WNA (maximum of 0.07 km-1, 0.08 km-1, 0.0017 km-1‧sr-1, 0.0015 km-1‧sr-1) at 532 and 1064 nm respectively. AD in WNA (maximum of 0.25) is significantly higher than in CSA (maximum of 0.05). There is a smooth change with the height of cloud extinction and backscatter in WNA and CSA, while there is a remarkable increase of cloud depolarization with height, whereby it is high in CSA and low in WNA due to high and low fraction of cirrus respectively. Altocumulus has the highest extinction in NA (0.0139 km-1), CA (0.058 km-1), WA (0.013 km-1), while low overcast transparent (0.76 km-1) below 1 km in SA. The major findings of this study may contribute to the improvement of our understanding of aerosol-cloud interaction studies in dominated dust and smoke aerosol regions.

基于TRIZ创新方法的微带天线阵列设计

发明问题解决的理论(teoriya resheniya izobreatatelskikh zadatch,TRIZ)作为一种理论工具和创新的现代技术,是一种科学创新方法,它提供了一套完整的创新工具,从不同角度分析问题并寻找的解决方案。本论文将TRIZ创新方法和天线设计相结合,通过运用TRIZ中最佳理想解定义和系统功能分析两种方法,导出天线设计中关键的需要优化参量;以此作为设计的出发点,基于高频天线结构仿真(high frequence structure simulator,HFSS)平台设计出一款工作于5.8 GHz的嵌入式微带单元天线阵列,经过仿真、实物制作、测试和优化,回波损耗(S11)达到-15 dB以下,并且具有较好的方向性及较窄的带宽。本论文为TRIZ运用于专业实践设计提供了一定的方法参考。

Integration of structural simulations into a real-time capable Overall System Simulation for complex mechatronic systems

To meet the rising demand of performing complex tasks in a highly technologized world,the development of mechatronic systems faces two major challenges:First,the system is integrated in a fast changing environment and has to cope with dynamically modified tasks and circumstances.At the same time,the development of new methods has to be fast,cost-effective and efficient.By taking care of both aspects simultaneously,simulations have become an acknowledged tool to cost-effectively and rapidly test and optimize new solutions for complex mechatronic systems,as they are common in,e.g.,robotics.Mostly,simulation methods are specialized for one purpose and thus used as a stand-alone tool to analyze the behavior of single components or certain aspects of the whole system.But with size and complexity of the system,the susceptibility to errors rises when the interaction between components fails.If a component shows minimal deviations to its nominal behavior,huge interdependencies between components of complex systems might cause system failure.The structural behavior of a single component is therefore as crucial to the functionality of the whole system as the interplay of all components.Both aspects have to be analyzed in parallel,which is nowadays barely considered.Consequently,this work presents the integration of structural simulations into the overall picture.The developed approach consists of a concept,an implementation and the validation for an automated bidirectional interaction to integrate results from Finite Element Analysis(FEA)into an existing,real-time capable Overall System Simulation for mechatronic systems in general and robotics in particular.

Gas-kinetic unified algorithm for computable modeling of Boltzmann equation and application to aerothermodynamics for falling disintegration of uncontrolled Tiangong-No.1 spacecraft

How to solve the hypersonic aerothermodynamics around large-scale uncontrolled spacecraft during falling disintegrated process from outer space to earth,is the key to resolve the problems of the uncontrolled Tiangong-No.1 spacecraft reentry crash.To study aerodynamics of spacecraft reentry covering various flow regimes,a Gas-Kinetic Unified Algorithm(GKUA)has been presented by computable modeling of the collision integral of the Boltzmann equation over tens of years.On this basis,the rotational and vibrational energy modes are considered as the independent variables of the gas molecular velocity distribution function,a kind of Boltzmann model equation involving in internal energy excitation is presented by decomposing the collision term of the Boltzmann equation into elastic and inelastic collision terms.Then,the gas-kinetic numerical scheme is constructed to capture the time evolution of the discretized velocity distribution functions by developing the discrete velocity ordinate method and numerical quadrature technique.The unified algorithm of the Boltzmann model equation involving thermodynamics non-equilibrium effect is presented for the whole range of flow regimes.The gas-kinetic massive parallel computing strategy is developed to solve the hypersonic aerothermodynamics with the processor cores 500~45,000 at least 80%parallel efficiency.To validate the accuracy of the GKUA,the hypersonic flows are simulated including the reentry Tiangong-1 spacecraft shape with the wide range of Knudsen numbers of 220~0.00005 by the comparison of the related results from the DSMC and N-S coupled methods,and the low-density tunnel experiment etc.For uncontrolling spacecraft falling problem,the finite-element algorithm for dynamic thermalforce coupling response is presented,and the unified simulation of the thermal structural response and the hypersonic flow field is tested on the Tiangong-1 shape under reentry aerodynamic environment.Then,the forecasting analysis platform of end-of-life largescale spacecraft flying track is established on the basis of ballistic computation combined with reentry aerothermodynamics and deformation failure/disintegration.

Amorphization of Ni_(61)Nb_(39) Alloy by Laser Surface Treatment

The surface of Ni_（61）Nb_（39） crystalline ingot was treated by laser surface melting with different processing parameters.A fully amorphous layer with a thickness of approximately 10μm could be produced on the top surface under optimal parameters.An amorphous-crystalline composite layer with the depth from 10 to 50μm,consisting of amorphous matrix and intermetallic phases of Ni_3 Nb and Ni_6Nb_7,could be formed.The micro-hardness（about 831HV）of the treated surface was remarkably improved by nearly 100% compared with the value of the crystalline substrate caused by the formation of the fully amorphous structure.A finite volume simulation was adopted to evaluate the temperature distribution in the laser-affected zone of Ni_（61）Nb_（39） alloys and to reveal the mechanism of glass formation in the laser-affected zone.

The research of traffic density extraction method under vehicular ad hoc network environment

Purpose–Traffic density is one of the most important parameters to consider in the traffic operationfield.Owing to limited data sources,traditional methods cannot extract traffic density directly.In the vehicular ad hoc network(VANET)environment,the vehicle-to-vehicle(V2V)and vehicle-to-infrastructure(V2I)interaction technologies create better conditions for collecting the whole time-space and refined traffic data,which provides a new approach to solving this problem.Design/methodology/approach–On that basis,a real-time traffic density extraction method has been proposed,including lane density,segment density and network density.Meanwhile,using SUMO and OMNet11 as traffic simulator and network simulator,respectively,the Veins framework as middleware and the two-way coupling VANET simulation platform was constructed.Findings–Based on the simulation platform,a simulated intersection in Shanghai was developed to investigate the adaptability of the model.Originality/value–Most research studies use separate simulation methods,importing trace data obtained by using from the simulation software to the communication simulation software.In this paper,the tight coupling simulation method is applied.Using real-time data and history data,the research focuses on the establishment and validation of the traffic density extraction model.

Adapting Nanotech Research as Nano-Micro Hybrids Approach Biological Complexity,A Review

Today＇s emergence of nano-micro hybrid structures with almost biological complexity is of fundamental interest. Our ability to adapt intelligently to the challenges has ramifications all the way from fundamentally changing research itself, over applications critical to future survival, to posing globally existential dangers. Touching on specific issues such as how complexity relates to the catalytic prowess of multi-metal compounds, we discuss the increasingly urgent issues in nanotechnology also very generally and guided by the motto ＇Bio Is Nature＇s Nanotech＇. Technology belongs to macro-evolution; for example integration with artificial intelligence （AI） is inevitable. Darwinian adaptation manifests as integration of complexity, and awareness of this helps in developing adaptable research methods that can find use across a wide range of research. The second half of this work reviews a diverse range of projects which all benefited from ＇playful＇ programming aimed at dealing with complexity. The main purpose of reviewing them is to show how such projects benefit from and fit in with the general, philosophical approach, proving the relevance of the ＇big picture＇ where it is usually disregarded.