Study on Interface mechanical behavior of steel tube reinforced concrete composite pile

Currently for the steel tube reinforced concrete composite pile research, although predecessors make a comprehensive research on the composite pile beating performance, design technology, but there are still many problems have not been solved, such as the steel tube reinforced concrete pile composite interracial force learn performance research is still in the initial stage. In this paper, we mainly discuss the research methods of several interface mechanical properties and propose the possibility of studying the mechanical properties of the steel tube reinforced concrete composite pile by using the principle of ultrasonic speckle.

Locating the cocktail and scaling-relation breaking effects of high-entropy alloy catalysts on the electrocatalytic volcano plot

High entropy alloys(HEAs)have been the star materials in electrocatalysis research in recent years.One of their key features is the greatly increased multiplicity of active sites compared to conventional catalytic materials.This increased multiplicity stimulates a cocktail effect and a scaling-relation breaking effect,and results in improved activity.However,the multiplicity of active sites in HEAs also poses new problems for mechanistic studies.One apparent problem is the inapplicability to HEA catalysts of the currently most popular mechanistic study method,which uses the electrocatalytic theoretical framework(ETF)based on the computational hydrogen electrode(CHE).The ETF uses a single adsorption energy to represent the catalyst,i.e.,a catalyst is represented by a'point'in the volcanic relationship.It naturally does not involve the multiplicity of active sites of a catalyst,and hence loses brevity in expressing the cocktail effect and scaling-relation breaking effect in HEA catalysis.This paper attempts to solve this inapplicability.Based on the fact that the adsorption energy distribution of HEAs is close to a normal distribution,the mean and variance of the adsorption energy distribution are introduced as descriptors of the ETF,replacing the original single adsorption energy.A quantitative relationship between the variance and the cocktail and scaling-relation braking effects is established.We believe the method described in this work will make the ETF more effective in mechanistic studies of HEA electrocatalysis.

Performance Evaluation of New Two Axes Tracking PV-Thermal Concentrator

The overall problem with PV （photovoltaic） systems is the high cost for the photovoltaic modules. This makes it interesting to concentrate irradiation on the PV-module, thereby reducing the PV area necessary for obtaining the same amount of output power. The tracking capability of two-axes tracking unit driving a new concentrating paraboloid for electric and heat production have been evaluated. The reflecting optics consisting of flat mirrors provides uniform illumination on the absorber which is a good indication for optimised electrical production due to series connection of solar cells. The calculated optical efficiency of the system indicates that about 80% of the incident beam radiation is transferred to the absorber. Simulations of generated electrical and thermal energy from the evaluated photovoltaic thermal （PV/T） collector show the potential of obtaining high total energy efficiency.

3D gel printing of VC reinforced high vanadium high-speed steel

Due to their high hardness and high strength,VC reinforced hard materials such as high vanadium high-speed steel(HVHSS)are not suitable for machining to obtain complex shape with low cost.Therefore,3D gel printing(3DGP)was employed to print HVHSS parts,using highly loaded slurry with 60%solid content as printing slurry.After printing parameters optimization,the printing sample had good surface quality,and obvious printing lines were observed.The extruded filament was in-situ cured,thus enough to maintain the designed shape.Uniform sintering shrinkage with a shrinkage rate of about 15%was obtained in the as-sintered sample with relative density of 99%.The surface roughness decreased from 6.5μm to 3.8μm.Fine carbides(<1μm)and dense microstructure were achieved.Besides,the as-sintered sample had comprehensive performance of HRC60 in hardness,3000 MPa in bend strength,and 20−26 J in impact energy.This study proposed one promising method to directly manufacture complex-shaped hard materials without subsequent machining.

基于无线传感器网络定位技术的图书馆智能管理创新

"互联网+"时代,信息技术的发展对图书馆的智能化管理工作提出了更高的要求。文章概述了无线传感器网络与定位技术,重点讨论了如何将WSN定位技术运用到图书智能管理,通过定位技术与大数据、云计算等信息技术的结合,推动图书馆智能系统建设和智能化发展。

Organic–inorganic nanohybrids for fluorescence, photoacoustic and Raman bioimaging

Organic-inorganic nanohybrid materials repre- sent a wide range of nanoscaled synthetic materials con- sisting of both organic and inorganic components that are linked together by covalent or non-covalent interactions, which have been widely employed in various fields such as optoelectronics, catalysis and biomedicine. As a result of this special combination, nanohybrid materials assemble numerous extraordinary features that provide great opportunities to improve their stability, multifunctions, biocom- patibility, eco-friendliness and other physical and mechanical properties. This review highlights recent re- search developments of functional organic-inorganic nanohybrid materials and their specific applications in bioimaging including fluorescent, Raman, photoacoustic and combined bioimaging. Future research directions and perspectives in this rapidly developing field are also discussed.

Self-healing materials enable free-standing seamless large-scale 3D printing

Three-dimensional(3 D)printing has had a large impact on various fields,with fused deposition modeling(FDM)being the most versatile and cost-effective 3 D printing technology.However,FDM often requires sacrificial support structures,which significantly complicates the processing and increases the cost.Furthermore,poor layer-to-layer adhesion greatly affects the mechanical stability of 3D-printed objects.Here,we present a new Print-Healing strategy to address the aforementioned challenges.A polymer ink(Cu-DOU-CPU)with synergetic triple dynamic bonds was developed to have excellent printability and room-temperature self-healing ability.Objects with various shapes were printed using a simple compact 3D printer,and readily assembled into large sophisticated architectures via self-healing.Triple dynamic bonds induce strong binding between layers.Additionally,damaged printed objects can spontaneously heal,which significantly elongates their service life.This work paves a simple and powerful way to solve the key bottlenecks in FDM 3D printing,and will have diverse applications.

Interface design enabled manufacture of giant metallic glasses

Developing materials with excellent properties has been the untiring pursuit of mankind.Metallic glasses(MGs)would be the ideal metallic materials if their size could be scaled up to be comparable to traditional metals.To address this challenge,a variety of approaches have been attempted over the past decades,including thermodynamicsbased alloy,3D printing and the recent artificial intelligenceguided optimal alloy.In this study,a facile and flexible route was demonstrated to manufacture giant MGs(GMGs)with diameters more than 100 mm through the thermo-joining process.The jointed GMG samples feature almost the same performance as the as-cast ones.The ability of manufacturing complex 3D components such as the Chinese Zodiacs was also demonstrated.Our approach might overcome the longstanding problem of glass forming ability(GFA)limitations in alloy systems and pave new concept and route to fabricate size unlimited MGs.

Numerical Investigation of Effect of Inlet Swirl and Total-pressure Distortion on Performance and Stability of an Axial Transonic Compressor

This paper represents numerical simulation of flow inside an axial transonic compressor subject to inlet flow distortion,to evaluate its effect on compressor performance and stability.Two types of inlet distortion,namely inlet swirl and total pressure distortion are investigated.To study the effect of combined distortion patterns,different combinations of inlet swirl and total pressure distortion are also studied.Results for cases with total pressure distortion indicate that hub radial distortion improves stability range of the compressor while tip radial distortion deteriorates it.An explanation for this observation is presented based on redistribution of flow parameters caused by distortion and the way it interacts with stall inception mechanisms in a transonic axial compressor.Results also show that while co-swirl patterns slightly improve stability range of the compressor,counter-swirl patterns diminish it.Study of combined distortion cases reveals that superimposition of effects of each individual pattern could predict the effect of a combined pattern on compressor's performance within an accuracy of 1%.However,it is unable to predict the associated effect on compressor's stability.

Improvements to the statistical theoretical model for wave breaking based on the ratio of breaking wave kinetic and potential energy

An improvement was proposed for the statistical theory of breaking erttrainment depth and surface whitecap coverage of real sea waves in this study. The ratio of the kinetic and potential energy was estimated on a theoretical level, and optimal constants were determined to improve the statistical theory model for wave breaking. We also performed a sensitivity test to the model constants. A comparison between the model and in situ observations indicated that the level of agreement was better than has been achieved in previous studies.

Development of impact resistant 3D printed multi-layer carbon fibre reinforced composites by structural design

In this study,a high impact resistant multi-layered composite consisting of continuous carbon fibre/nylon(CCF)and short carbon fibre/nylon(SCF)layers is developed via 3D printing technology.The effect of CCF/SCF layers configuration on the impact resistance is investigated by low-velocity impact test,and the impact failure mechanism of the 3D printed composites is explored by microscopic observations and finite element(FE)simulation analysis.The results show that the 3D printed multi-layered composite with SCF layers distributed in the middle(HFA)exhibits higher impact resistant performance than the specimens with alternating SCF/CCF layers(HFB)and CCF layers distributed in the middle(HFC).The effect of CCF/SCF layers proportion on the impact performance is also studied by FE simulation,and the results show that the specimen with a CCF/SCF proportion of 7.0 exhibits the highest impact strength.