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Synthesis of ZrAlN coatings with thermal stability at high temperature

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Science China(Technological Sciences) 2006年第5期49卷 576-581页

作者： li dejun College of Physics and Electronic Information Science Tianjin Normal University Tianjin 300074 China

Dry machining will result in elevated temperatures at the tool surface (800–1000°C). So, coating materials that can provide protection for cutting tools at these temperatures are of great technological interests. ZrAlN coating is proposed to possess high-temperature stable structural and mechanical properties due to the addition of the alloying element. ZrAlN coatings were grown using a dc reactive magnetron sputtering. The XRD and nano indenter were employed to investigate the effects of reaction gas partial pressure and substrate bias on structural and mechanical properties, as well as high-temperature stability. The ZrAlN coating, when deposited under optimum conditions (?37 V substrate bias and 2 × 10?5 Pa N2 partial pressure), showed smooth surface with thermal stable hardness. Its internal stress was relaxed from 2.2 to 0.7 GPa after annealing. Formation of Al2O3 and ZrO2 crystalline phases should be related to thermal stability of the coatings.

关键词： ZrAlN coating, magnetron sputtering, thermal stability.

SIMPliFIED MODEL AND ITS APPliCATION FOR WAVEMAKING INDUCED BY EXPLOSION

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Journal of Hydrodynamics 1995年第1期7卷 33-44页

作者： Shen, Guoguang li, dejun Tianjin Univ Tianjin China

This paper pays attention to the analysis of overall macroscopic process of wavemaking induced by explosion. Based on establishing the simplified model and MAC method, the numerical simulations for formulating crater induced by touching water surface explosion, the bubble jumping out of the water surface induced by underwater explosion as well as hollow column formation for large equivalent explosion etc were carried out. In order to predict the wave field, the scheme simulated by falling and evoluting of an ″equivalent cylinder″ were proposed. In addition to researching the wavemaking response in a harbour, two joining methods in time domain were presented. The results indicate that the model and numerical methods are feasible.

关键词： Bubbles (in fluids) Computer simulation Explosion testing Mathematical models Surface waves

Surface Modification of Hexamethylated Disiloxane Plasma Polymerized Medical Polyurethane

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Chinese Physics Letters 1994年第2期11卷 87-90页

作者： li dejun ZHAO Jie Department of Physics Tianjin Normal UniversityTianjin 300074

Surface biomedical properties of plasma polymerization on medical polyurethane were *** disiloxane(MI)plasma polymerization was performed at a power of 100 W with the polymerization-time ranging from 1 to *** results showed that hexamethylated disiloxane plasma polymerization resulted in an increase from 30.52 to 37.44s in the recalcification *** the same time,the anticoagulability of polymerized samples for the polymerization time of 2-5min was 2.5 times that of the *** of x-ray photoelectron spectroscopy,electron spin resonance analysis showed that plasma polymerization decomposed some of CN bonds to form new SiN bonds and to increase the amount of radicals in polyurethane,which were the main reasons for surface modification.

关键词： polymerization polyurethane bonds

NUMERICAL CALCULATION OF HYDRODYNAMIC COEFFICIENT FOR A FLOATING BODY IN WAVES

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China Ocean Engineering 1989年第3期4卷 307-319页

作者： li, dejun Shen, Guoguang Tianjin Univ China

A preliminary numerical model of the buoyant drum by wave action is presented, which is based on the Finite Boundary Element Method of the source distribution. A series formula of Green's function is used for the derivation of the model. In the paper the calculated results of the examples for a sphere and a buoyant drum are close to the data in some references. A subject of great interest to ocean engineers is the response a floating body suffers in ocean waves. In this paper, the oscillatory motion of a buoyant drum is analysed and a calculating method is presented. Applying this calculating method, the hydrodynamic coefficient for any kind of floating bodies can be obtained.

关键词： Cylinders Wave Effects Mathematical Models Oceanography

Synthesis of nanoscale multilayered ZrN/W coatings by ion beam assisted deposition

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Science China(Technological Sciences) 2007年第2期50卷 206-212页

作者： li dejun ZHANG JingJing WANG MingXia College of Physics and Electronic Information Science Tianjin Normal UniversityTianjin 300074China

ZrN/W multilayered coatings with different modulation periods at the nanoscale have been synthesized at different N+ beam bombarding energies using IBAD. Various characterization techniques such as XRD, AES, nano indenter and profiler were employed to investigate the influence of modulation period and bombarding energy on microstructure and mechanical properties of the coatings. The results showed that all superlattice coatings had better mechanical properties than the monolithic ZrN and W coatings. At an optimal condition with 300 eV N+ beam bombarding energy and 8―9 nm modulation period, XRD pattern possessed a sig- nificantly structural mixture of strong ZrN (111), W (110), as well as weak ZrN (220) textures in the multilayered coating. The optimal condition resulted in higher hardness (26 GPa), elastic modulus (310 GPa) and fracture resistance of the coat- ing than other conditions.

关键词： IBAD ZrN/W multilayered coating nanoscale

Spatially controlled lithium deposition on li_(x)Cu_(y)P_(z) arrays enabling highly stable lithium metal batteries

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Journal of Materials Science & Technology 2023年第21期152卷 212-219页

作者： Ying Zhou Xiangru Sun Peiran Tan Yueming Wang Hongyang Dong dejun li Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials College of Physics and Materials ScienceTianjin Normal UniversityTianjin 300387China

lithium(li)metal is a potential anode for high-energy-density batteries because of its low potential and ultrahigh ***,the li dendrites formation,the ununiform li deposition,and the growth of li dendrites hamper its application,especially under high deposition capacity/high ***,a spatially controlled li deposition mode with array-oriented morphology is achieved based on the novel mixed ion/electron-conducting li_(x)Cu_(y)P_(z) arrays constructed on Cu foil,which can be facile fabricated via an in-situ transformation of metal *** calculations indicate the excellent lithiophilicity and low li diffusion barrier of the arrays,especially for the li_(2)CuP phase,which are conducive to ho-mogenizing the li nucleation/deposition of ***,such mixed conducting arrays promote fast li+diffusion via the continuous li+pathways as well as modulate the li+flux/electric ***,the arrays with enlarged specific surface area and open spaces reduce the local current density and alle-viate the volume fluctuation of ***,a dendrite-free li anode is obtained under a high rate(20 mA cm^(–2))or a high deposition capacity(10 mAh cm^(–2)).In addition,even if the negative/positive ratio reduces to only 1.1,the full cells still perform outstanding stability for over 200 *** work empha-sizes the importance of the design of the framework in terms of the intrinsic properties and structure and reveals a pathway for developing li metal batteries.

关键词： li metal li dendrites Metal phosphates lithiophilic Mixed conductor Full cell

Influence of Ar/N_2 Flow Rate on Structure and Property for TaN/NbN Multilayered Coatings

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Journal of Materials Science & Technology 2007年第4期23卷 461-464页

作者： Xuehua ZHANG Yuanbin KANG Sipeng liU Qiang li Ying YANG Xiangyun DENG dejun li College of Physics and Electronic Information Science Tianjin Normal University Tianjin 300074 China

TaN/NbN multilayered coatings with nanoscale bilayer periods were synthesized at different Ar/N2 flow rates by RF （radio frequency） magnetron sputtering. XRD （X-ray diffraction） and Nano Indenter System were employed to investigate the influence of Ar/N2 flow rate （FAr：FN2） on microstructure and mechanical properties of the coatings. The low-angle XRD pattern indicated a well-defined composition modulation and layer structure of the multilayered coating. All multilayered coatings almost revealed higher hardness than the rule-of-mixtures value of monolithic TaN and NbN coatings. At FAr：FN2=10, the multilayered coating possessed desirable hardness, elastic modulus, internal stress, and fracture resistance, compared with ones synthesized at other Ar/N2 flow rates. The layered structure with strong mixture of TaN （110）, （111）, （200） and Nb2N （101）textures should be related to the enhanced mechanical properties.

关键词： RF magnetron sputtering TaN/NbN multilayered coatings Nanoscale mechnical properties

Effects of Co doping on electronic structure and electric/magnetic properties of La_(0.1)Bi_(0.9)FeO_3 ceramics

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Science China(Physics,Mechanics & Astronomy) 2013年第10期56卷 1861-1865页

作者： WANG ShouYu FENG Yu liU WeiFang YU DaShu li dejun College of Physics and Electronic Information Science Tianjin Normal University Department of Information Material Science and Engineering Guilin University of Electronic Technology Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology Faculty of Science Tianjin University

In this work,we report the influence of Co-doping on the electronic band structure,dielectric and magnetic properties of La0.1Bi0.9Fe1-xCoxO3 ceramics.X-ray photoelectron spectroscopy investigation shows that Co dopant can shift the valence band spectrum and core-level lines of constituent elements towards higher bind energy regions simultaneously increase the concentration of oxygen vacancies in *** effects of dopant are discussed with focus given to the Co-doping induced enhancement of electrical conductivity and resistive switching phenomena.

关键词： BiFeO3 Co doping electronic structure XPS

Topography modulates effects of nitrogen deposition on microbial resource limitation in a nitrogen-saturated subtropical forest

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Forest Ecosystems 2021年第4期8卷 914-922页

作者： Hao Chen Junjie Tang Xibin Sun Kayan Ma Huaihai Chen dejun li State Key Laboratory of Biocontrol School of EcologySun Yat-sen University510275 GuangzhouChina Key Laboratory of Agro-ecological Processes in Subtropical Region Institute of Subtropical AgricultureChinese Academy of Sciences410125 ChangshaHunanChina Huanjiang Observation and Research Station for Karst Ecosystems Institute of Subtropical AgricultureChinese Academy of Sciences547100 HuanjiangChina

Background:Nitrogen(N)saturation theory proposes that an ecosystem might switch from N limitation to carbon(C),phosphorus(P),or other nutrient limitations if it receives continuous N ***,after N limitation is removed,which nutrient is the most limited and whether topography modulates such change is rarely tested at a microbial ***,we conducted a two-year N addition experiment under two different topography positions(i.e.a slope and a valley)in a N-saturated subtropical *** enzyme activity was measured,and ecoenzymatic stoichiometry indexes were calculated as indicators of microbial resource ***:In the valley,two-year N addition changed the activity of all studied enzymes to various *** a result,microbial C limitation was aggravated in the valley,and consequently microbial decomposition of soil labile organic C increased,but microbial P limitation was alleviated due to the stoichiometry *** the slope,however,N addition did not significantly change the activity of the studied enzymes,and did not alter the status of microbial resource ***:These results indicate that C is a more limited element for microbial growth than P after removing N limitation,but we also highlight that topography can regulate the effect of N deposition on soil microbial resource limitation in subtropical *** findings provide useful supplements to the N saturation theory.

关键词： Nitrogen deposition Topography Nutrient limitation N saturation Enzyme activity Enzymatic stoichiometry