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Thermal expansion anomaly and spontaneous magnetostriction of Tb_2Fe_(15)Cr_2 compound

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Rare Metals 2006年第2期25卷 156-160页

作者： HAO Yanming ZHOU Yan zhao miao Department of Physics Tianjin Normal University Tianjin 300074 China

The structural and magnetic properties of Tb2Fe15CF2 compound were investigated by means of X-ray diffraction and magnetization measurements. Tb2Fe15Cr2 compound has a hexagonal Th2Ni17-type structure. Negative thermal expansion was found in Tb2Fe15Cr2 compound from 372 to 452 K by X-ray dilatometry. The coefficient of the average thermal expansion is α^- =-3.14×10^-5 K^-1. The magnetostrictive deformations from 292 to 450 K were calculated. The result showed that the spontaneous volume magnetostrictive deformation ms remains nearly constant with increasing temperature up to 360 K, but decreases with the further increase of temperature. The spontaneous linear magnetostrictive deformation λc along the c axis decreases with increasing temperature. The spontaneous linear magnetostrictive deformation, λa, in the basal-plane increases with increasing temperature up to 360 K, but decreases with further increasing temperature.

关键词： condensed matter physics spontaneous magnetostriction X-ray diffraction Tb2Fe15Cr2 compound negative thermal expansion

Spontaneous volume magnetostriction of Dy_2AlFe_(12)Mn_4 compound

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Rare Metals 2006年第1期25卷 43-46页

作者： HAO Yanming ZHOU Yan zhao miao Department of Physics Tianjin Normal University Tianjin 300074 China

The structure and magnetic properties of Dy2AlFe12Mn4 compound have been investigated by means of X-ray diffraction and magnetization measurements. The Dy2AlFe12Mn4 compound has a hexagonal Th2Ni17-type structure. Negative thermal expansion was found in Dy2AlFe12Mn4 compound from 229 to 280 K by X-ray dilatometry. The coefficient of the average thermal expansion is α^- =-3.8×10^-5 K^-1. The magnetostrictive deformations from 105 to 270 K have been calculated by means of the differences between the experimental values of the lattice parameters and the corresponding values extrapolated from the paramagnetic range. The result shows that the spontaneous volume magnetostrictive deformation ωs decreases from 6.2 × 10^-3 to near zero with the temperature increasing from 105 to 270 K, the spontaneous linear magnetostrictive deformation λc along the c axis is much larger than the spontaneous linear magnetostrictive deformation λa in basal-plane at the same temperature except close to 249 K.

关键词： condensed matter physics spontaneous volume magnetostriction X-ray diffraction, Dy2AlFe12Mn4 compound negative thermal expansion

Optomechanical properties of a degenera te nonperiodic cavity chain

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Frontiers of physics 2019年第2期14卷 31-38页

作者： miao-miao zhao Zhuo Qian Bang-Pin Hou Yong Liu Yong-Hong zhao College of Physics and Electronic Engineering Center for Computational SciencesSichuan Normal UniversityChengdu 610068China State Key Laboratory of Metastable Materials Science and Technology & Key Laboratory for Microstructural Material Physics of Hebei Province School of ScienceYanshan UniversityQinhuangdao 066004China

The absorption of single-cav计y and double-cavity optomechanical systems and periodic optomechanical lattices has previously been investigated extensively. In this paper, we present the absorption of a nonperiodic cavity chain. where the absorption value on the resonance point shows switchable dips or peaks, according to whether the optomechanical interaction is at an odd or even-numbered position in the chain. Meanwhile, the value of absorption due to the optomechanical interaction varies with the number of the bare cavities. The calculated results may have some novel applications, such as detecting the position of the movable mirror in a long cavity chain, which would be useful in quantum information processing based on optomechanical systems.

关键词： optomechanics optomechanically induced transparency (OMIT)

Effects of geometric configuration on droplet generation in Y-junctions and anti-Y-junctions microchannels

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Acta Mechanica Sinica 2015年第5期31卷 741-749页

作者： zhao-miao Liu Li-Kun Liu Feng Shen College of Mechanical Engineering and Applied Electronics Technology Beijing University of Technology

Droplets generation in Y-junctions and anti-Yjunctions microchannels are experimentally studied using a high speed digital microscopic system and numerical *** configuration of a microchannel,such as Y-angle（90°,135°,-90° and-135°）,channel depth and other factors have been taken into *** is found that droplets generated in anti-Y-junctions have a smaller size and a shorter generation cycle compared with those in Yjunctions under the same experimental *** observing the internal velocity field,the vortex appearing in continuous phase in anti-Y-junctions is one of the key factors for the difference of droplet size and generation *** is found that droplet size is bigger and generation cycle is longer when the absolute angle value of the intersection between the continuous and the dispersed phases（i.e.,the angle between the main channel and the continuous phase or the dispersed phase channel） *** droplet＇s size is influenced by the Y-angle,which varies with the channel depth in *** Y-angle has a positive effect on the droplet generation cycle,but a smaller height-width ratio will enhance the impact of a continuous and dispersed phase＇s intersection angle on the droplet generation cycle in Y-junctions microchannels.

关键词： Microfluidics Y-junctions and anti-Yjunctions microchannels Y-angle Height-width ratio in cross section

Heavy metals in sediments of Yellow Sea and East China Sea: Chemical speciation,distribution,influence factor,and contamination

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Journal of Oceanology and Limnology 2021年第4期39卷 1277-1292页

作者： miao zhao Shenghui ZHANG Haitao HAN Dawei PAN Key Laboratory of Coastal Environmental Processes and Ecological Remediation Yantai Institute of Coastal Zone Research(YIC)Chinese Academy of Sciences(CAS)Coastal Environmental ProcessesResearch Center for Coastal Environment Engineering Technology of Shandong ProvinceYICCASYantai 264003China University of Chinese Academy of Sciences Beijing 100049China

Metal species and the degree of environmental pollution are related to the hydrogen sulfide(H_(2)S),an important product of early diagenesis that can react with metals to form stable *** investigate the eff ects of H_(2)S to metals and evaluate metal environment eff ect in the sediments of the East China Sea(ECS)and Yellow Sea(YS),geochemical characteristic and spatial distribution of nine heavy metals and H_(2)S profile were *** H_(2)S content and lower metal content was observed in the sediments 10 cm in depth in the North Yellow Sea and the west coast of South *** pollution load index(I_(pl))indicates that the southern coast of Shandong Peninsula underwent moderate pollution(I_(pl)=1)of heavy metals and no heavy metal pollution appeared in other areas(I_(pl)<1).To some extents,the ecological risk of Cd and As enrichment was moderately severe in all *** chance of heavy metal combination to be toxic in ECS and YS during summer was 21%.In addition,correlation between H_(2)S content and metals in both solid and porewater phases was obvious,corroborating important eff ect of H_(2)S on metal ***,H_(2)S could aff ect the spatial distributions of heavy metals in porewater directly and be indicative of potential biological eff ects of combined toxicant groups in the study region.

关键词： hydrogen sulfide heavy metal East China Sea and Yellow Sea sediment porewater risk assessment

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A study on carbon emission calculation in operation stage of residential buildings based on micro electricity usage behavior:Three case studies in China

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Building Simulation 2024年第1期17卷 147-164页

作者： Menghan Niu Ying Ji miao zhao Jiefan Gu Aonan Li Beijing Key Laboratory of Green Built Environment and Energy Efficient Technology Beijing University of TechnologyBeijing 100124China College of Architecture and Urban Planning Tongji UniversityShanghai 201804China The Bartlett School of Architecture University College LondonWC1E 6BTUK

Along with the improvement of social productivity and living standard,residential buildings generate a growing portion of carbon emissions,especially during the operation ***,energy use behaviors are usually ignored in carbon emission *** study focuses on calculating carbon emissions during the operation stage for residential buildings based on the characteristics of energy use behaviors in different ***,we investigated energy use behaviors in dwellings across three cities in China:Xi'an,Shanghai and ***,we established calibrated carbon emission models and optimization models with different green building measures for residential *** results of this research reveal a significant disparity between the energy usage habits of residents in different climate *** carbon emissions of residential electricity bills in Xi'an,Shanghai and Fuzhou are 13.6 kgCO_(2)/(m^(2)·a)(excluding central heating),29.3 kgCO_(2)/(m^(2)·a)and 17.2 kgCO_(2)/(m^(2)·a),*** carbon emissions account for 32.2%-64.1% of the *** comparison to the model based on internal standard setting,the accuracy of the models using actual internal has improved by 25.9%-37.4%.The three-star green building methods have the highest carbon reduction rate among different star buildings,the emission reduction rates are around 30%.This study's findings are useful for carbon emission calculation and green building design of residential buildings in the future.

关键词： residential building energy usage behavior energy simulation carbon emissions

Dynamic temperature prediction of electronic equipment under high altitude long endurance conditions

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Chinese Journal of Aeronautics 2018年第6期31卷 1189-1197页

作者： Liping PANG miao zhao Kun LUO Yongli YIN Zhou YUE School of Aeronautic Science and Engineering Beihang University Beijing 100083 China National Key Laboratory of Human Factors Engineering China Astronaut Research and Training Center Beijing 100094 China Aviation Key Laboratory of Science and Technology on Aero Electromechanical System Integration. Nanjing 211102 China

Unmanned Aerial Vehicle（UAV） is developing towards the direction of High Altitude Long Endurance（HALE）. This will have an important influence on the stability of its airborne electronic equipment using passive thermal management. In this paper, a multi-node transient thermal model for airborne electronic equipment is set up based on the thermal network method to predict their dynamic temperature responses under high altitude and long flight time conditions. Some relevant factors are considered into this temperature prediction model including flight environment,radiation, convection, heat conduction, etc. An experimental chamber simulating a high altitude flight environment was set up to survey the dynamic thermal responses of airborne electronic equipment in a UAV. According to the experimental measurement results, the multi-node transient thermal model is verified without consideration of the effects of flight speed. Then, a modified way about outside flight speed is added into the model to improve the temperature prediction performance. Finally, the corresponding simulation code is developed based on the proposed model. It can realize the dynamic temperature prediction of airborne electronic equipment under HALE conditions.

关键词： Airborne electronic equipment High altitude long endurance Multi-node transient thermal model Node thermal network Temperature prediction

Protective effects of (-)-epigallocatechin-3-gallate on D-galactose-induced neuronal apoptosis in mice

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Neural Regeneration Research 2009年第12期4卷 1024-1029页

作者： miao He Lin zhao Weifan Yao Haishan zhao Fujun Chen Minjie Wei Department of Pharmacology Pharmaceutical College of China Medical University Shenyang 110001 Liaoning Province China

BACKGROUND： The neuroprotective effects of （-）-epigallocatechin-3-gallate （EGCG）, the main polyphenolic constituent of green tea, have been widely reported. However, the action mechanisms, in particular in D-galactose-induced aging mice, remain poorly understood. OBJECTIVE： The present study investigated the protective effects of EGCG on D-galactose-induced hippocampus neuronal apoptosis in aging mice, as well as the relationship with expression of p751CD, JNK2, and p53 proteins. DESIGN, TIME AND SETTING： A randomized, controlled, molecular biological, animal experiment was performed at the Laboratory of Pharmacology, Pharmaceutical College of China Medical University, China, from September 2006 to July 2008. MATERIALS： D-galactose and EGCG （Sigma, USA）, as well as terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling （TUNEL） In Situ Cell Apoptosis Detection Kit （Promega, USA）, were used in this study. METHODS： A total of 64 mice were equally and randomly divided into D-galactose model, low-dose EGCG, high-dose EGCG, and control groups. Mice in the D-galactose model, low-dose EGCG, and high-dose EGCG groups were subcutaneously injected with 3% D-galactose （150 mg/kg）, daily for 6 weeks, to establish a mouse model of aging. Mice in the control group were treated with saline （5 mL/kg）. At 3 weeks following injection, mice in the low-dose EGCG and high-dose EGCG groups were orally administered EGCG at a dose of 2 mg/kg and 6 mg/kg, respectively, once a day, for 4 consecutive days. Mice in the control and D-galactose model groups received distilled water （5 mL/kg）. MAIN OUTCOME MEASURES： Memory function was evaluated using a step-through passive avoidance test. Neuronal apoptosis in the mouse hippocampus was detected using TUNEL staining. Expression levels of the intracellular domain of the p75 neurotrophin receptor （p75NTR）-p751CD, JNK2, and p53 proteins in the hippocampus were determined using Western blot analysis. RESULTS： The aging mouse mode

关键词： (-)-epigallocatechin-3-gallate D-galactose neuronal apoptosis aging

Enhanced energy-absorbing and sound-absorbing capability of functionally graded and helicoidal lattice structures with triply periodic minimal surfaces

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International Journal of Minerals,Metallurgy and Materials 2023年第10期30卷 1973-1985页

作者： miao zhao Zhendong Li Jun Wei Chua Chong Heng Lim Xinwei Li Department of Mechanical Engineering National University of SingaporeSingapore 117411Singapore Chongqing Key Laboratory of Metal Additive Manufacturing(3D Printing) Chongqing UniversityChongqing 400044China Department of Mechanical Engineering Newcastle UniversitySingapore 567739Singapore

Lattice structures have drawn much attention in engineering applications due to their lightweight and multi-functional *** this work,a mathematical design approach for functionally graded(FG)and helicoidal lattice structures with triply periodic minimal surfaces is *** types of lattice structures including uniform,helicoidal,FG,and combined FG and helicoidal are fabricated by the additive manufacturing *** deformation behaviors,mechanical properties,energy absorption,and acoustic properties of lattice samples are thoroughly *** load-bearing capability of helicoidal lattice samples is gradually improved in the plateau stage,leading to the plateau stress and total energy absorption improved by over 26.9%and 21.2%compared to the uniform sample,*** phenomenon was attributed to the helicoidal design reduces the gap in unit cells and enhances fracture *** acoustic properties,the design of helicoidal reduces the resonance frequency and improves the peak of absorption coefficient,while the FG design mainly influences the peak of absorption *** broad range of frequency from 1000 to 6300 Hz,the maximum value of absorption coefficient is improved by18.6%-30%,and the number of points higher than 0.6 increased by 55.2%-61.7%by combining the FG and helicoidal *** study provides a novel strategy to simultaneously improve energy absorption and sound absorption properties by controlling the internal architecture of lattice structures.

关键词： additive manufacturing lattice structure triply periodic minimal surface energy absorption sound absorption