检索结果-内蒙古大学图书馆

Microstructure and water corrosion behavior of (Lu0.2Yb0.2Er0.2Tm0.2Sc0.2)2Si2O7 high-entropy rare-earth disilicate coating for Sic coated c/c composites

引用

JOURNAL OF THE EUROPEAN cERAMIc SOcIETY 2023年第8期43卷 3647-3657页

作者： chen, Guohui Zhang, Yulei Guo, Xiaotong Fu, Yanqin Kong, Jing'an Gai, Wenhan Zhang, Pengfei Northwestern Polytech Univ Shaanxi Prov Key Lab Fiber Reinforced Light Compos Xian 710072 Peoples R China

In order to make carbon/carbon composites suitable for application in gas turbine engine, it is necessary to develop environmental barrier coatings (EBcs) to protect them from reacting with water vapor. In our previous work, a novel high-entropy rare-earth disilicate (Lu0.2Yb0.2Er0.2Tm0.2Sc0.2)2Si2O7 ((5RE0.2)2Si2O7) has been developed and verified as a promising candidate for EBcs. In this work, the (5RE0.2)2Si2O7 coating was syn-thesized on the surface of Sic coated c/c composites by supersonic atmospheric plasma spraying method. The protective performance and mechanism of this coating under high temperature water vapor environment was explored in detail. Results showed that the weight change of the sample coated with (5RE0.2)2Si2O7 was only 0.2% after corrosion for 100 h at 1500 oc, which proved that (5RE0.2)2Si2O7 coating could significantly improve the resistance of c/c composites against water vapor corrosion. This work may provide theoretical basis for the design and application of high-entropy rare-earth silicates as EBcs.

关键词： c c composites High-entropy rare earth disilicates Environmental barrier coatings Supersonic atmospheric plasma spraying Water vapor corrosion

来源：评论

学校读者我要写书评

暂无评论

Effect of h-BN addition on friction and wear properties of c/c-Sic composites fabricated by LSI

引用

INTERNATIONAL JOURNAL OF APPLIED cERAMIc TEcHNOLOGY 2022年第1期19卷 108-118页

作者： Niu, Zi-bo chen, Fu Xiao, Peng Li, Zhuan Pang, Lang Li, Yang Cent South Univ State Key Lab Powder Met Changsha 410083 Peoples R China Cent South Univ Natl Key Lab Sci & Technol Natl Def High Strength Changsha Peoples R China

Hexagonal boron nitride (h-BN) has excellent oxidation resistance, self-healing function, and self-lubricating properties, which can significantly improve the oxidation resistance of c/c-Sic composites in low or medium temperature condition and affect their tribological properties and mechanisms. In this work, c/c-Sic and c/c-BN-Sic composites were prepared by the same molding, carbonization and liquid silicon infiltration (LSI) processes and the influences of h-BN addition on their microstructure, tribological properties, and mechanisms were investigated. h-BN addition can promote the formation of friction film and reduce the oxidation wear of the composites. compared with c/c-Sic composites, due to more lubricant components and different matrix structure, the c/c-BN-Sic composite shows lower wear rate (reduced by 53%) and moderate rather than too high coefficient of friction (coF) and its coF is less influenced by braking velocity. Moreover, the friction process is more stable and does not appear clamping stagnation phenomenon in high braking speed condition.

关键词： c c-Sic composite h-BN modification microstructure tribological properties

来源：评论

学校读者我要写书评

暂无评论

Fiber orientations effect on process performance for wire cut electrical discharge machining (WEDM) of 2D c/Sic composite

引用

INTERNATIONAL JOURNAL OF ADVANcED MANUFAcTURING TEcHNOLOGY 2019年第1-4期102卷 507-518页

作者： He, Wenbin He, Shaotai Du, Jinguang Ming, Wuyi Ma, Jun cao, Yang Li, Xiaoke Zhengzhou Univ Light Ind Henan Prov Key Lab Intelligent Mfg Mech Equipment Zhengzhou 450002 Henan Peoples R China

Adopting orthogonal experiments, relevant machinability in wire cut electrical discharge machining (WEDM) of 2D c/Sic composite was studied. The effects of electrical machining parameters (namely pulse width, pulse interval, and the number of tubes) on machining speed and surface roughness were analyzed. In addition, the effect of fiber orientations on the machinability was also studied. The main effect and interaction of the selected electrical machining parameters were also discussed. The key results show that the fiber orientation effect on machining speed plays a weaker role in WEDM of this composite. For machining speed, the number of tubes and the pulse interval have no interaction in both of machining directions A and B. For surface roughness, the number of tubes and the pulse interval have obvious interaction in both of machining directions A and B. The fiber orientation has a larger effect on the surface roughness than that on machining speed in WEDM of this composite. After analyzing the material removal mechanism, some new significant results show that the carbon fibers are removed in the form of transverse and longitudinal fracture. Interfacial debonding between fiber carbon and Sic matrix, pit, and recast layer form on the machined surface. Micro cracks are observed in the carbon fiber, and a part of the micro cracks are cross.

关键词： c Sic composite Fiber orientation Wire cut electrical discharge machining Machining speed Surface roughness

来源：评论

学校读者我要写书评

暂无评论

Experimental investigation on fatigue property at room temperature of c/Sic composites machined by rotary ultrasonic milling

引用

JOURNAL OF THE EUROPEAN cERAMIc SOcIETY 2021年第6期41卷 3341-3356页

作者： Xue, Feng Zheng, Kan Liao, Wenhe Shu, Jing Miao, Didi Nanjing Univ Sci & Technol Sch Mech Engn Nanjing 210094 Peoples R China

Rotary ultrasonic milling technology (RUM), as a surface strengthening machining method, was proposed to utilize in processing of c/Sic composites for enhancing anti-fatigue performance innovatively. Static tensile, intermittent fatigue and residual strength test were carried out. Due to constant impingement of high-frequency and low-amplitude vibration, surface residual compressive stress was formed near 2 GPa maximally. Axial thermal residual stress in fiber achieved -662.4 MPa proved by loading-unloading test. The peak value of fatigue damage parameter was reduced significantly. RUM surface restrains most of interface cracks because of residual compressive stress, and hinder the growth of fiber cracks for better machined surface quality. The damage accumulation, the first stress redistribution and fiber reinforcement stage were delayed. Average damage rate was decreased by 80.5 %. Residual tensile strength of RUM c/Sic was improved after fatigue, up to 95.8 % of tensile strength. The strengthening effect from RUM on fatigue property of c/Sic is significant and valuable.

关键词： Rotary ultrasonic milling c Sic composite Anti-fatigue performance Fatigue damage Residual stress

来源：评论

学校读者我要写书评

暂无评论

Simulation of SiGe:c HBTs using neural network and adaptive neuro-fuzzy inference system for RF applications

引用

INTERNATIONAL JOURNAL OF ELEcTRONIcS 2013年第7期100卷 959-975页

作者： Karimi, Gholamreza Banitalebi, Roza Sedaghat, Sedigheh Babaei Razi Univ Dept Elect Engn Kermanshah Iran

In this article, the small-signal equivalent circuit model of SiGe:c heterojunction bipolar transistors (HBTs) has directly been extracted from S-parameter data. Moreover, in this article, we present a new modelling approach using ANFIS (adaptive neuro-fuzzy inference system), which in general has a high degree of accuracy, simplicity and novelty (independent approach). Then measured and model-calculated data show an excellent agreement with less than 1.68x10(-5)% discrepancy in the frequency range of higher than 300 GHz over a wide range of bias points in ANFIS. The results show ANFIS model is better than ANN (artificial neural network) for redeveloping the model and increasing the input parameters.

关键词： small-signal equivalent circuit model SiGe c HBT ANN ANFIS

来源：评论

学校读者我要写书评

暂无评论

Development of-80 °c storage for Allium shoot tips using D cryo-plate method

引用

PLANT cELL TISSUE AND ORGAN cULTURE 2021年第1期144卷 115-122页

作者： Tanaka, Daisuke Sakuma, Yoshinori Yamamoto, Shin-ich Arizaga, Miriam Valle Niino, Takao Matsumoto, Toshikazu Natl Agr & Food Res Org Genet Resource Ctr Tsukuba Ibaraki Japan Univ Tsukuba Tsukuba Ibaraki Japan Shimane Univ Fac Life & Environm Sci Matsue Shimane Japan

D cryo-plate method was successfully adapted for storage at - 80 degrees c and - 196 degrees c of Allium shoot tips. The optimal D cryo-plate method using garlic shoot tips for the storage at - 80 degrees c and - 196 degrees c includes preculture of shoot tips for 2 days at 25 degrees c on solidified 1/2 MS medium containing 0.3 M sucrose, then placing them in wells on an aluminum cryo-plate, embedded in calcium alginate gel. Osmoprotection was performed by immersing the cryo-plates with shoot tips for 30 min at 25 degrees c in 2.0 M glycerol and 1.0 M sucrose. The optimal dehydration time of shoot tips was for 30 to 180 min at 25 degrees c. cooling was performed by transferring the samples on the cryo-plate into 2 ml cryotubes, then cooling into a deep freezer at - 80 degrees c for 14 days or directly plunging into liquid nitrogen (- 196 degrees c) for 60 min. The regrowth rate of shoot tips stored both at - 80 degrees c and - 196 degrees c was almost 100%. This optimized procedure was applied to seven Allium spp. The average regrowth rates after cooling at - 80 degrees c and - 196 degrees c were 95.3 and 94.0%, respectively. Thus, the storage of shoot tips at - 80 degrees c using D cryo-plate method is considered to be efficiently applicable for practical genebank storage. Key message D cryo-plate method was successfully adapted for storage at - 80 degrees c of Allium shoot tips. Grass transition temperature of shoot tips after air desiccation were - 39.4 degrees c.

关键词： Allium Aluminum plate D cryo-plate DSc Garlic Japanese shallot − 80 ° c Rakkyo

来源：评论

学校读者我要写书评

暂无评论

Static data-flow analysis for software product lines in c Revoking the preprocessor's special role

引用

AUTOMATED SOFTWARE ENGINEERING 2022年第1期29卷 35页

作者： Schubert, Philipp Dominik Gazzillo, Paul Patterson, Zach Braha, Julian Schiebel, Fabian Hermann, Ben Wei, Shiyi Bodden, Eric Paderborn Univ Paderborn Germany Univ Cent Florida Orlando FL 32816 USA Univ Texas Dallas Dallas TX USA Fraunhofer IEM Paderborn Germany Tech Univ Dortmund Dortmund Germany

Many critical codebases are written in c, and most of them use preprocessor directives to encode variability, effectively encoding software product lines. These preprocessor directives, however, challenge any static code analysis. SPLlift, a previously presented approach for analyzing software product lines, is limited to Java programs that use a rather simple feature encoding and to analysis problems with a finite and ideally small domain. Other approaches that allow the analysis of real-world c software product lines use special-purpose analyses, preventing the reuse of existing analysis infrastructures and ignoring the progress made by the static analysis community. This work presents VarAlyzer, a novel static analysis approach for software product lines. VarAlyzer first transforms preprocessor constructs to plain c while preserving their variability and semantics. It then solves any given distributive analysis problem on transformed product lines in a variability-aware manner. VarAlyzer 's analysis results are annotated with feature constraints that encode in which configurations each result holds. Our experiments with 95 compilation units of OpenSSL show that applying VarAlyzer enables one to conduct inter-procedural, flow-, field- and context-sensitive data-flow analyses on entire product lines for the first time, outperforming the product-based approach for highly-configurable systems.

关键词： Inter-procedural static analysis Software product lines Preprocessor LLVM c c plus plus

来源：评论

学校读者我要写书评

暂无评论

Microstructure, Mechanical and Ablation Properties of Transpiration cooling Applied to c/c-Sic composite for Novel Anti-ablation Material

引用

APPLIED cOMPOSITE MATERIALS 2022年第6期29卷 2147-2163页

作者： Wang, Pei Guo, Yonggang Du, Sanming Jia, Yunchao Zhang, Hongbo Yin, Jian Henan Univ Technol Sch Mat Sci & Engn Zhengzhou 450001 Peoples R China Henan Univ Technol Sch Mech Engn Zhengzhou 450001 Peoples R China Henan Univ Sci & Technol Natl United Engn Lab Adv Bearing Tribol Luoyang 471000 Peoples R China Cent South Univ State Key Lab Power Met Changsha 410083 Peoples R China

Taking the advantages of porous ceramic (c/c-Sic composite) and transpiration cooling (copper alloy), c/c-Sic-cu composite was fabricated to attain a novel anti-ablation material for high temperature structure application of aerospace systems, via chemical vapor deposition and infiltration technologies. The effects of Sic content on microstructure, thermal conductivity, mechanical and ablation properties of c/c-Sic-cu composite were investigated. As the Sic content increases from 0 vol% to 25.12 vol%, thermal conductivity, flexural strength and ablation resistance are improved by 84.99%, 78.76% and 53.68%, respectively. Thermal conductivity and thermal diffusivity exhibit proportional linear correlation with Sic content. The high Sic content could shorten the yield stage and increase the breaking strength during the flexural fracture process. When the Sic content is 25.12 vol%, the formation continuous and compact anti-ablation (SiO2) layer is formed by oxidizing and melting fluidity processes during oxyacetylene ablation test, and the protective layer covers the ablation surface and slows down the oxidative ablation, which combines with the transpiration cooling effect of copper alloy to further improve ablation resistance of c/c-Sic-cu composite.

关键词： c c-Sic-cu composite chemical vapor deposition Transpiration cooling Ablation property

来源：评论

学校读者我要写书评

暂无评论

High Energy and High Power Lithium-Ion Hybrid Supercapacitors with Prolonged cycle Life Based on High-Rate capability Materials: Li4Ti5O12, Activated carbon, Li3V1.95Ni0.05(PO4)3/c

引用

cHEMELEcTROcHEM 2020年第7期7卷 1631-1643页

作者： Secchiaroli, Marco calcaterra, Silvia Marassi, Roberto Wohlfahrt-Mehrens, Margret Dsoke, Sonia Univ Camerino Div Chem Sch Sci & Technol Via S Agostino 1 I-62032 Camerino Italy Zentrum Sonnenenergie & Wasserstoff Forsch Baden Accumulator Mat Res ECM ZSW Lab Batterietechnol eLaB Lise Meitner Str 24 D-89081 Ulm Germany KIT IAM Hermann von Helmholtz Pl 1 D-76344 Eggenstein Leopoldshafen Germany

Two lithium-ion hybrid supercapacitors (LiHSs) based on high power active materials like Li3V1.95Ni0.05(PO4)(3)/c (LVNP/c), Li4Ti5O12 (LTO) and activated carbon (Ac) are investigated as high energy and high power devices. Both LiHSs are assembled by using a bi-material negative LTO:Ac electrode (50 : 50), able to deliver 38.3 mAh g(-1) at 35 A g(-1) (200 c for LTO), and to retain 80 % of the initial capacity over 10000 cycles at 17.5 A g(-1). Two positive electrodes are employed in complete devices: a battery-type LVNP/c and a bi-material LVNP/c:Ac (65 : 35) based electrodes, for two LiHSs named Hybrid A and Hybrid B, respectively. The energies of the LiHSs are evaluated from 0.05 to 10 A g(-1), and at different cell voltages (2.6, 2.7 and 2.8 V). The best performance is obtained with Hybrid A cycled between 0-2.7 V, that with 36.3 Wh L-1 at 4.3 kW L-1, possesses an energy density five time higher than that of the Ac||Ac (6.8 Wh L-1). Despite both LiHSs charged up to 2.8 V possess superior energy values, at this cell voltage Hybrid A and Hybrid B retain only 11 % and 8 % of the initial capacity cycled over 8000 cycles at 10 A g(-1), respect to the 75 % and 81 % of the same systems cycled up to 2.7 V.

关键词： lithium-ion hybrid supercapacitors Li(3)V1 95Ni0 05(PO4)(3) c Li4Ti5O12 activated carbon high energy density LiHSs

来源：评论

学校读者我要写书评

暂无评论

Time-dependent creep fatigue damage evolution in c/Sic composite: Theory and analytical prediction

引用

cERAMIcS INTERNATIONAL 2022年第14期48卷 20731-20742页

作者： Li, Longbiao Reynaud, Pascal Fantozzi, Gilbert Nanjing Univ Aeronaut & Astronaut Coll Civil Aviat 29 Jiangjun Ave Nanjing 211106 Peoples R China Univ Lyon INSA Lyon MATEIS UO CNRS 5510 7 Ave Jean Capelle Villeurbanne Cedex F-69621 Lyon France

In this paper, the time-dependent damage evolution in carbon fiber-reinforced silicon carbide ceramic-matrix composites (c/Sic cMcs) under creep fatigue loading at elevated temperature was analyzed using a micromechanical approach. Synergistic effects of creep fatigue peak stress level and damage in the matrix and the interface on time-dependent damage evolution in c/Sic composites were analyzed. Next, relationships of timedependent creep fatigue damage mechanisms, damage parameters, environmental temperature and duration were determined. Then, the effects of composite constituent properties, creep fatigue damage state, environmental temperature, and duration on time-dependent damage evolution in c/Sic composites were analyzed. Furthermore, time-dependent composite strain response and interface debonding and oxidation state in c/Sic composite under different creep fatigue peak stress levels were predicted. Under creep fatigue loading, the composite internal damage evolution contributed to the increased time/temperature-dependent composite peak strain. Hysteresis-based damage parameters were developed and utilized to monitor c/Sic composite internal damage evolution. Under creep fatigue loading, the hysteresis area and width increased with oxidation duration to a peak value and remained constant, and the hysteresis modulus decreased with oxidation duration.

关键词： c Sic creep fatigue Damage evolution Time -dependent Interface debonding Matrix cracking

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：