bluuebunny/crossref_metadata_2025 huggingface dataset:
The dust-jacket considered
Authors: Smith Margit J
Published: February 2019

This article addresses the  history of protective book coverings from earliest times to their current use;  their design as it mirrors changes in the graphic arts and materials over the past century; scholarly, commercial, and marketing use of dust-jackets, collections in institutions. Treatment in library settings and availability to students and users will also be discussed. Findings, suggestions and instructions for their preservation,  pros and cons of retention, importance in the rare book trade, and the production of fake and facsimile dust-jackets are also considered.
Les formations en Conservation-Restauration et le développement de la profession
Authors: Hoppenbrouwers René
Published: February 2019

Cet article retrace dans ses grandes lignes, l'évolution du métier de la conservation-restauration ainsi que le rôle joué par les organisations professionnelles dans la définition des formations de haut niveau (universitaires ou équivalentes). Soulignant l'importance de l'interdisciplinarité, de la multidisciplinarité et de la diffusion des savoirs -et notamment par l'édition scientifique en Open Access, l'auteur expose en particulier le rôle déterminant d'ENCORE dans le développement de l'enseignement de la discipline au niveau européen.
An evaluation of solid carbon dioxide (CO2) blasting as a cleaning method to remove soot from textiles after smouldering fire and fire, with the possibility to transfer the method to historical textiles within a museum context
Authors: Grønlund Mari
Published: February 2019

The main issue for the master dissertation was to evaluate if solid carbon dioxide (CO2) blasting as a cleaning method could be used to remove soot from textiles after smouldering fire, with the possibility to transfer the method to historical textiles. The experiments in the thesis were carried out with textile dummies. From the results, it was concluded the method in itself showed a potential, but the cleaning equipment was not appropriate.
Enhancing Education in Conservation through Research and Innovation Projects
Authors: Panagiaris George , Malea Ekaterini , Rapti Stavroula , Pournou Anastasia
Published: February 2019

Le laboratoire de la conservation des matériaux organiques (Département de la Conservation des antiquités et des œuvres d'art - TEI d'Athènes) cherche toujours à améliorer l'éducation en donnant aux étudiants des cycles supérieurs la possibilité de participer à des projets internationaux de recherche et d'innovation. Ce document analyse les objectifs éducatifs et les acquis d'apprentissage des mesures susmentionnées et présente les résultats d'une enquête réalisée par des questionnaires adressés aux étudiants.
Lost in Reintegration?
Authors: Grenda Magdalena
Published: February 2019

This article describes different approaches to the issue of image reintegration and filling in the areas of loss in photographs and photographic postcards. The approach varies depending on the context of the photographs’ usage, the owner’s expectations and the will of the photographer. The paper discusses treatments of various photographic artifacts and presents the complexity of conservation problems associated with photographic objects.  The diversity of solutions and decisions proves that there are numerous factors to consider and that there are no simple answers when it comes to decision making.
La foire aux valeurs
Authors: Brunel Georges
Published: February 2019

L'auteur examine l'usage contemporain du terme "valeur" en rapport avec le patrimoine, et revient sur l'emploi théorique et pratique qu'en fait Aloïs Riegl.
The role of educators in promoting collaborative research
Authors: Golfomitsou Stavroula , Katrakazis Theocharis , Heritage Alison
Published: February 2019

This paper examines some of the current science policy paradigms set at international level to promote open science and participatory research, and discusses how key factors necessary for successful collaboration can usefully contribute to the training of future conservation professionals through group work and research-based learning programmes.
Historique et variations de la restauration des œuvres de Nicolas Schöffer
Authors: Schöffer Éléonore de Lavandeyra
Published: February 2019

Ce texte reprend la transcription de l’intervention d’Éléonore de Lavandeyra Schöffer lors de la première journée d’étude, le 3 novembre 2016 à la Villa des Arts (Paris). Il est accompagné de la vidéo de la communication. Après avoir présenté les œuvres et l’atelier de Nicolas Schöffer au public, Éléonore Schöffer y présente ses expériences et réflexions liées aux restaurations des œuvres de son mari à travers le temps. Elle passe en revue les différentes catégories d’œuvres de l’artiste et quelques clés de compréhension sur leurs évolutions.
Entre authenticité et extrapolation : l’interprétation des œuvres de Nicolas Schöffer
Authors: D’haenens Manon
Published: February 2019

Cette communication propose une réflexion sur l’interprétation des œuvres de Nicolas Schöffer à partir de cas pratiques. Elle se base sur la définition de la conservation-restauration comme interprétation en tant que processus de décision en vue de la transmission des œuvres d’art. Les notions d’authenticité, intentionnalité et extrapolation sont remises en perspective à partir d’exemples caractéristiques de l’art contemporain.
Casing Shear Deformation Based on Micro Seismic Data
Authors: Zeng Yi Jin , Xi Yan , Ding Shi Dong , Li Jun , Hao Xin Yu , Li Fang Yuan , Wang Hai Tao
Published: February 2019

Casing shear deformation, which is caused by fault slipping, is the main morphology of casing deformation occurred during multistage fracturing. In order to determine the relationship between fault slipping and casing shear deformation, the micro seismic data collected from engineering field which can reflect the reality of the formations was analyzed. A new numerical model was developed, and the influential factors on casing shear deformation were studied, including the fault slip distance of lower and upper interface, fault dip angle, the thickness of cement sheath and casing. The results of research shows that: (1) Fault is easily activated by fracturing, which was the main reason of casing shear deformation; (2) The greater the fault dip angel, the slip distance, the greater the casing shear deformation; (3) Increasing the wall thickness of casing or cement sheath is beneficial to decrease the degree of the shear deformation; (4) Two ways can be used to avoid and control the casing shear deformation, one is keeping the designed horizontal segment of well trajectory keep away from fracture-developed area, or be parallel to natural fracture, the other is using stage cementing technology. Research results can provide important reference for design and control of casing integrity during multistage fracturing in shale gas wells.
Influence of Casing Pressure Test on Seal Integrity of Cementing First Interface
Authors: Jiang Ji Wei , Li Jun , Liu Gong Hui , Xi Yan , Li Wai
Published: February 2019

Casing pressure test is an important link of the oil and gas well cementing, but excessive casing pressure test may cause stress failure or plastically deformation of the cement sheath, and generate micro-annulus on the casing-cement sheath cemented surface, then lose seal integrity of the cement sheath. According to the basic theory of elastoplastic mechanics and considering the volume invariance of plastic strain and the influence of elastic strain on volume change, the Mohr-Coulomb criterion is used to establish the casing-cement sheath-surrounding rock combination model. The paper also derived the formula for calculating the micro-annulus of the casing pressure test, and analyzed the influence of the internal pressure of the casing during the pressure test and the elastic modulus of the cement sheath on the radial contact stress of the cement sheath cementation interface after the cementing operation is completed. Results show that: (1) The generation of micro-annulus of casing pressure test is determined by the pressure increase process and the pressure relief process. The pressure increase process may lead the cement sheath into plasticity, and the radial stress at the interface turns into tensile stress and the micro-annulus could appear at the first interface by the decrease of internal pressure during pressure relief process. (2) The varying internal pressure has a great influence on the fatigue failure of the cement sheath, so the continuous multiple casing pressure test should be avoided after the cementing is completed. (3) Under the condition of maintaining the integrity of the cement sheath, increasing the tensile strength of the cement stone and reducing the elastic modulus of the cement stone can improve the pressure bearing capacity of the first interface during the casing pressure test. The model can provide a theoretical basis for the mechanical parameter design of the cement sheath, and provide guidance for on-site construction to reduce or avoid the risk of failure of the first interface seal integrity for the casing pressure test.
Life Cycle Assessment of Lead Production in China
Authors: Sun Wan Yi , Gong Xian Zheng , Sun Bo Xue , Ding Qing
Published: February 2019

This study analyzed the environmental impacts due to lead production in China, which is the largest producer and consumer of lead in the world, by the method of life cycle assessment (LCA). Based on the Chinese refined lead smelting process, a process-based life cycle assessment model was established to assess the environmental load of lead production system which includes the processes of mining, beneficiation, smelting, electrorefining and transportation. The result shows that the cumulative consumption of electricity and the cumulative emission of green house gases for the production of 1t of refined lead are 1111.93kWh and 2.06E+03kg CO2 eq, respectively. Smelting process is the largest contributor to the environmental impact load, accounting for 51.16% of the total environmental impact. The environmental category of human toxicity potential(HTP), accounting for 35.26% of the total environmental impact, is the largest contributor between different environmental categories to the total environmental impact, followed by metal depletion potential(MDP) and fossil depletion potential(FDP), accounting for 27.94% and 11.80% of the total environmental impact, respectively. Improving the resource efficiencies of the processes of smelting and beneficiation, and using cleaner energy to generate electricity are the key approaches to reduce the overall environmental impact of lead production in China.
Effect of Chemical Composition on the Properties of Reconstructed Steel Slag
Authors: Xu Ying , Wang Qiao Ling , Hu Chen Guang , Yang Shan Shan
Published: February 2019

The steel slag is not widely or extensively used because of its poor volume stability and low cementitious activity. In this paper, the solid waste fly ash, quicklime and slag discharged from iron and steel enterprises are used as conditioning components in the experiment. In order to improve the cementitious activity and volume stability of steel slag, the high temperature reconstruction experiment of steel slag was completed. The effects of C/S (2.50~3.14), S/A (4.5~17. 81) on the cementitious activity and volume stability of reconstructed steel slag were investigated by means of the tests of compressive strength, scanning electron microscope, X-ray diffraction, lithofacies test, stability test and so on. The results showed that the cementitious activity and volume stability of the reconstructed steel slag were improved in the higher C/S or lower S/A. The cementitious activity and volume stability of the reconstructed steel slag were improved with the increase of CaF2 content. By analyzing the cementitious activity and volume stability of the reconstructed steel slag, the optimum technological parameters are obtained as follows: C/S is 2.70 , S/A is 5.78, the content of CaF2 is 4%.
Effect of the Cement Raw Meal Rate Value on SNCR deNOx Efficiency with NH3 as Reducing Agent
Authors: Wang Ya Li , Li Nan , Zhang Hong Zhan , Cui Su Ping , Zhang Yun Ning
Published: February 2019

Many complex factors can affect the process of SNCR in cement calciner, and the cement raw meal rate value is a relatively important one. In the present study the influence of the cement raw meal rate value on the SNCR denitration efficiency was investigated in a tubular reactor with a space velocity of 27000 ml/h in the temperature range of 700-1100 °C, and the oxygen concentration was 5% and both the inlet concentration of NO and NH3 was designed as 1000ppm. The results showed that the denitrification rate of SNCR decreased with the increase of the lime saturation factor (KH) of cement raw meal and increased with the increase of aluminum rate (IM) of cement raw meal at 700~900 °Crecommended that the cement raw meal with low KH, medium silica acid rate (SM) and high IM should be used. In the temperature range of 900~1100 °C the denitrification efficiency of SNCR increased with the KH and decreased with the increase of IM. Based on the experimenyal results it is suggested that the cement raw meal with high KH, high SM and low IM should be adopted.
Analysis of Mechanical Performance and Microstructure of Steel Slag Processed with Accelerated Carbonation
Authors: Wu Qi Sheng , Gu Hong Xia , Yang Tao , Zhang Chang Sen , Min Zhi An , Wu Yang
Published: February 2019

The accelerated carbonation with different pressure steaming conditions was used to process the steel slag, so the slag could turn into a primary cementitious product with carbonation activity. XRD, FTIR, TG, N2 absorption BET surface area analyzer and SEM were used to characterize the mineral and chemical compositions and microstructure of each sample before and after the carbonation. The results show that: the carbonation products with different morphologies are formed under different temperature conditions. The optimum temperature for the accelerated carbonation for processing the steel slag is selected to be 90 °C, which results in the compressive strength of 32.8 MPa. The BET specific surface area of the steel slag reduces after carbonation, the sample density increased after carbonation.
Influence of Different Surface Treatments on Fatigue Life of 7050 Al Alloy
Authors: Li Nan , Li Hai Tao , Zhou Jing Yi , Liu Hong Tao , Liu Chang Kui , Qu Shi Yu
Published: February 2019

The fatigue life of 7050 Al alloy samples after different surface treatments, i.e., as-machined, anodizing, shot peening, and shot peening followed by anodizing, had been tested. The shot peening treatment specimens presented the longest average fatigue life. The fatigue life of anodizing treatment specimens decreased by 69.3% and 78.8% at 215 MPa and 260 MPa stress levels than as-machined ones. Introducing the shot peening treatment before anodizing can increase the fatigue life by 220% / 296.9% at 215 MPa/260 Mpa than that only treated by anodizing. The effect of the surface treatments on the fatigue life were studied by performing surface morphology investigation, residual stress measurements and fracture surface analysis.
Interfacial Reaction of CoCrFeNi High Entropy Alloy in Molten Al
Authors: Hu Yao , He Jun Tao , Wu Yu Cai , Dong Yong , Zhang Zheng Rong
Published: February 2019

In this paper, we studied the element diffusion behaviors of the multi-principal CoCrFeNi high entropy alloy in molten Al at 700°C. Microstructure, structure and microhardness in the diffusion interfaces of CoCrFeNi and Al are studied by the X-ray diffraction, the scanning electron microscopy, the energy spectrometry, and the microhardness tester. The results showed that a complex chemical reaction occurred at the interface between the high-entropy alloy and the Al. A mixture of FCC + BCC solid solution layer was first formed. Then a bulk Al13Cr2 compound formed near the Al of the solid solution layer. With the increase of dipping time, the thickness of the solid solution layer remained unchanged, and the compounds gradually changed into spheres distributed in the Al matrix. The formation of BCC structure makes the hardness of the solid solution layer up to 450HV, and the existence of the compound also increases the hardness of the Al matrix significantly.
Effect of Primary Annealing Temperature on Primary and Secondary Recrystallization in Strip-Cast Grain-Oriented Silicon Steel
Authors: Lu Xiang , Lan Meng Fei , Fang Feng , Zhang Yuan Xiang , Wang Yang , Yuan Guo , Zhang Wei Na , Wang Guo Dong
Published: February 2019

Grain-oriented silicon steel was produced by strip casting route. The effect of different annealing temperature on primary annealing and secondary annealing was investigated. The result showed that the average grain diameter increased and the grain uniformity was gradually destroyed with the increasing annealing temperature. Regardless of annealing temperature, the primary texture consisted of strong γ-fiber and weak λ-fiber. With the increase of annealing temperature, the γ-fiber intensity increased. In addition, the Goss component was not shown at 780-880 °C but appeared at 980 °C. After secondary annealing, complete abnormal grain growth occurred in all samples and the average grain diameter increased with the primary annealing temperature. The Goss sharpness of secondary grains firstly increased and then decreased with a peak value obtained at 830 °C. This result was explained in terms of the combination of the inhibiting force, primary grain diameter and primary texture.
Microscopic Failure Mechanism of Zinc Layer in Galvanized Sheet during Sheet Forming Process
Authors: Huang Yao , Wang Lei Gang , Ma Xiang , Liu Lei
Published: February 2019

Sheet forming of galvanized metals presents a great challenge for automobile industry. This is partially caused by a significant induced plastic deformation and high contact friction during forming, which results in pulverization, flaking and failure seen in the zinc layer. Cupping tests is used to study the formability of the galvanized sheets, for a better understanding of microscopic failure mechanisms of the zinc layer. The results show that during the cupping of the galvanized sheet, the zinc layers of each deformed zone encounter varying degrees of failure behaviors. The regions next to the fillets of the punch and the blank holder ring are more serious. In these severe failure areas, the residual stresses in the zinc layer are shown as tensile in nature; and increase with the degree of deformation increasing. The galvanized layers rupture prematurely prior to any damage seen in the steel substrate; thus leading to chalking, flaking and final failure. The results provide a theoretical guidance for improving formability of galvanized sheets.
Effect of Hot Rolling Process Parameters on Microstructure Transformation and Microstructure of 45MnSiV Steel
Authors: Wang Yun Long , Chen Yin Li , Wei He , Zhao Yi Na , Liu Ze Sheng
Published: February 2019

The effects of final rolling temperature, cooling rate and deformation on phase transition point, the duration of the phase transition and the pearlite laminar layer of non-quenched and tempered steel 45MnSiV were studied by simulating the process of rolling and post-rolling cooling on Gleeble-3500 thermal simulator and thermal expansion tester. The results show that: the ferrite and pearlite transformation temperature ranges from 510 °C to 700 °C, and the bainite transformation temperature ranges from 400 °C to 500 °C when the steel is continuously cooled at a final rolling temperature of 950 °C, and the martensite transforming temperature is 300 °C under high cooling rate (> 10 °C/s); The pearlite laminar spacing decreases with the decrease of final rolling temperature. It can be seen that the rolling deformation increases the temperature at which the test steel undergoes a phase change at each cooling rate by comparing the results of deformation and no-deformation test at 950 °C. The effect of time advance on the phase transition zone of ferrite and pearlite is particularly obvious, but the effect on the phase transition temperature and time of the bainite and martensite phase transition is not obvious. When the final rolling temperature remains constant, the Rockwell hardness value of the test steel gradually increases, and the pearlite layer spacing decreases with the decrease of ferrite transformation temperature gradually and the increase of the cooling rate.
Titanium Nitride and Niobium Carbide in the Ferritic Stainless Steel and the Influence to Casting Macrostructure
Authors: Du Heng Ke , Xia Dian Xiu , Shang Cheng Jia , Chen Kun
Published: February 2019

Titanium and niobium were applied to stable the carbon or nitrogen which dissolved ferritic stainless steel for improving the anti-corrosion performance. The titanium nitride and niobium carbide had been formed during solidification processing. For understanding those precipitates how to influence the casting macrostructure, three steels that had different content of niobium and the fixed content of titanium had been designed. The result showed the casting macrostructure of ingot and the grain size of the centre-equiaxed crystal zones had different tendency. And the titanium nitride and niobium carbide had interacted.
Effect of Annealing Processes on Microstructures and Mechanical Properties of Medium Mn Steel
Authors: Dong Rui , Lv Ke , Guo Hui , Zhao Ai Min
Published: February 2019

Two annealing processes have been designed to process a medium Mn steel, namely, the traditional direct two-phase annealing process and the pre-quenching treatment before two-phase annealing process, called two stage annealing process. The experimental results indicated that different annealing processes resulted in completely different microstructures, and a significant difference in mechanical properties. The microstructures of the steel after direct two-phase annealing process were coarse tempered martensite matrix and retained austenite. In this case, the optimum mechanical properties with total elongation of 29.87 %, tensile strength of 932 MPa and UTS*TE of 27.84 GPa•% were achieved after annealing at 625 °C for 18 h. The annealing process with pre-quenching treatment could realize two kinds of retained austenite, including acicular austenite and blocky austenite. The process with pre-quenching treatment could improve mechanical properties as well as shorten the optimal annealing time. The steel with two stage annealing process achieved optimal mechanical properties after pre-quenching and annealing at 625 °C for 4 h with tensile strength of 1177 MPa, total elongation of 30.92 % and UTS*TE of 36.39 GPa•%.
Effect of Heat Treatment on the Precipitation Behavior and Hardness of the Second Phase of 0Cr21Mn17Mo3N0.8 High Nitrogen Alloys
Authors: Yang You , Xu Yun Xiu , Chen Zi Wei , Huang Yan
Published: February 2019

The effects of different heat treatment processes on the morphology, quantity and size of the precipitated nitrides phase of 0Cr21Mn17Mo3N0.8 high nitrogen alloy were studied. The microstructure of the alloy was observed and characterized by metallographic microscope, transmission electron microscope, etc. And the hardness of high nitrogen alloy under different treatment processes were tested. The results showed that sample alloy was cooling in the furnace after heat preservation of 1140°C for 8h. Lamellar nitride is precipitated from the alloy, its composition is Cr2N, its size is about 50-100nm, and the precipitation process mainly occurs 1-2mm below the surface layer. This can make the alloys to form surface-reinforced composites. Meanwhile, the hardness of the alloy has increased significantly from 29.3HRC to 61.3HRC, because of the precipitation of the second phase. The high nitrogen alloys after slow cooling treatment were treated with spheroidization at the temperature lower than that of the complete austenitizing, and the layered deposition began fusing at 950°C. Under the temperature of 1120°C heat preservation for 8h, then water quenching, slice layer deposition completely dissolved into granule, and the particle size is about 20nm to 50nm, the alloy of hardness after spheroidizing has decreased to 48.3HRC.
Study of Helium Bubble Induced Hardening in BCC-Fe by Molecular Dynamics Simulation
Authors: Jia Li Xia , He Xin Fu , Wu Shi , Wang Dong Jie , Cao Han , Dou Yan Kun , Yang Wen
Published: February 2019

The interaction between an moving edge dislocation and helium bubble was studied in BCC-Fe using Molecular dynamics（MD）simulation. Edge dislocation passed the bubble via cut mechanism. A step with a length of b is left on both sides of the bubble after dislocation left away. The influence of simulation temperature, defect size and He/V ratio in bubble on critical resolved shear stress (CRSS) for dislocation to shear bubble were investigated. The CRSS increases with increasing defect sizes, and decreases with increasing temperature. When He/V ratio is at the range of 0-1, CRSS depends weakly on the He/V ratio. The estimated obstacle strength of helium bubble based on MD simulations is acceptable and reasonable agreement with one deduced from the dispersion barrier-hardening model applied to experimental results.
Effects of Gas Film Hole on Mechanical Property and Oxidative Damage of Turbine Blades
Authors: Hu Chun Yan , Kong Zhi Qiang , Liu Xin Ling , Tao Chun Hu
Published: February 2019

With the development of aero-engine with high specific flux, high thrus-weight ratio, and high turbine inlet temperature, it is an effective way to improve the cooling efficiency by designing dense gas film holes on the blade surface of the turbine blades, especially at the intake side. However, the introduction of gas film holes destroys the geometrical integrity of the blade structure, resulting in a multiaxial high stress state of the blade material around the small holes, which seriously affects the strength and life of the cooling blades. In addition, the geometry design of the gas film holes also directly affects the temperature and the oxidation rate of the turbine rotor blades. In this paper, the researches on the mechanical properties and oxidative damage of the gas film holes at home and abroad in recent years have been systematically introduced. The effects of gas film holes on the durability and fatigue properties, the high temperature oxidation behavior of single crystal superalloys, and the thin-walled effect of oxidative damage of gas film holes have been systematically described.
Anti-Oxidation Performance on Graphite Prepared by Plasma Electrolysis Technology
Authors: Zhang Yong Fu , Chen Wei Wei , Bu Ai Ming , Xiang Yan , Cheng Huan Wu , Wang Lu
Published: February 2019

A new technology was introduced to prepare anti-oxidant coating on graphite. The whole procedure could be controlled easily when compared with the conventional technology. According to the preliminary experiment, the combining power between the substrate and the coating was good. The coating was uniform and well-distributed. Anti-oxidation test at 1300 oC showed that the coating could prevent substrate from being oxidized. So the new technology had a great advantage while applied in the industrial production and it would lay a solid foundation for the large scale industrialization.
Crystal Structure and Multiferroic Behaviors of Solid Solution (1-y)BiFe(1-x)MnxO3-yBaTiO3
Authors: Wu Mei Mei , He Lin Feng , Wei Guo Hai , Li Yu Qing
Published: February 2019

It is expected that BiFeO3-based materials will have both ferroelectricity and ferromagnetism. (1-y)BiFe(1-x)MnxO3-yBaTiO3 system was prepared using solid state reaction method. The goal of this study is to uncover the impacts of Mn doping and BaTiO3 content on the crystal structure, magnetism and ferroelectric properties. By forming a solid solution with BaTiO3, stable perovskite BiFeO3 was achieved. The rhombohedrally distorted (1-y)BiFe(1-x)MnxO3-yBaTiO3 showed weak ferromagnetism due to the composition of BaTiO3 and the doping of Mn ion. 0.8BiFe0.9Mn0.1O3-0.2BaTiO3 and 0.7BiFe0.9Mn0.1O3-0.3BaTiO3 ceramics exhibited typical P-E hysteresis loops.
Continuous Fabrication of Temperature-Responsive Hydrogel Fibers with Bilayer Structure by Microfluidic Spinning
Authors: Zhou Mei Ling , Hu Dan Mei , Shao Yu Jie , Ma Jing Hong , Gong Jing Hua
Published: February 2019

Temperature-responsive hydrogel fibers with bilayer structure were prepared by a microfluidic spinning device with a Y-shaped connector. The bilayer hydrogel fibers include two layer with different chemical composition. One layer is the ionic crosslinking hydrogel of calcium alginate (CA) and the other layer is temperature-responsive hydrogel which is semi-interpenetrating polymer networks (semi-IPN) of linear poly (N-isopropylacrylamide) (PNIPAM) and CA. The bilayer hydrogel fibers were evaluated by morphology observation, tensile stress measurement, temperature-responsive actuation test and equilibrium swelling ratio test. The results show that the prepared hydrogel fibers have obvious double layer structure with different porous structures. The bilayer hydrogel fibers can bend in water at 50 °C and the bending rate is influenced by the diameter of the fiber. Moreover, the diameter of the hydrogel fibers can be controlled by changing the flow rates of spinning fluids.
Deformation and Residual Stress Measurement of Alumina Ceramics after Dynamic Impacts
Authors: Gao Yuan Fei , Si Zhao Xia , Zhao Meng Yu , Yang Li Xue
Published: February 2019

Alumina ceramics sintered at 1350°C ~ 1550 °C with various mechanical properties were tested using a minitype compressed air gun with mini WC material bullets impacting at a fixed bullet speed of 100 m/s. The resistance behaviour and deformation were recorded by visual examination. Cr3+fluorescence was used to measure the induced residual stress and plastic deformation. The results show that the alumina with finest grains size and highest hardness is more effective in the bulletproof, the alumina sintered at 1450 °C experienced both the greatest extents of compressive residual stress (3.25 GPa) and plasticity (24 cm-1shift).
Laser-MIG Hybrid Keyhole Welded 6mm Steel/Aluminum Butt Joints
Authors: Lu Dong Qi , Cui Li , Chen Hong Xi , Chang Yao Qing , Peng Zhi Bo , He Ding Yong
Published: February 2019

At present, the connection of steel/aluminum joints has been widely used in industrial fields such as aerospace, marine and automotive.Although the joints with excellent performance can be obtained by the solid phase welding methods such as explosion welding and friction welding, the production process is complicated and the efficiency is low, and the practical application is limited.Laser welding has attracted a lot of attention from researchers because of its advantages of high energy density, small welding deformation and fast welding speed.However, in the single-beam laser welding process, there are problems such as high joint assembly precision, excessive energy density, and easy formation of depressions in the weld.The newly developed laser-MIG (Metal Inert Gas) hybrid welding not only retains the advantages of laser welding, but also fully exploits the advantages of MIG welding, improves weld formation, improves the stability of the welding process, and helps solve the single-beam laser welding problems.In this paper, the laser deep penetration welding process of 5.5 mm thick E36 steel and 6 mm thick 5083 aluminum alloy butt joint was studied by laser-MIG composite welding heat source. Compared with the single laser welding process, the influence of wire feed speed on the welded steel/aluminum joint, joint interface structure and joint mechanical properties was studied.The results show that the laser-MIG composite deep-melt welding can obtain good steel/aluminum butt joint performance. At a laser power of 3.25 kW, a wire feed speed of 1.5 m / min, a laser offset of 0.5 mm and a defocus of 0 mm, the tensile strength of the steel/aluminum butt joint is as high as 85.0 MPa.Laser-MIG hybrid welding can improve the dent defects of a single laser welded steel/aluminum butt joint. The amount of acicular Fe4Al13 phase in the intermetallic compound was significantly reduced, and the resistance of the steel/aluminum joint was increased from 8.6 kN to 12.7 kN.
Joints Properties of Aluminum Foams/Aluminum Plate by Transient Liquid Phase Bonding Process
Authors: Huang Ben Sheng , Wen Xiong , Zhao Xing , Li Guang Wen
Published: February 2019

Aluminum foams/aluminum plate was transient liquid phase diffusion bonded with Cu/Al/Cu composite interlayer, then the investigation on joint microstructure, element diffusion and joint strength was conducted at 565°C. The results showed that, there was a significant grain boundary penetration phenomenon near the interface and it was more seriously at the side of aluminum foams. The XRD results showed indicated that the main phases near the interface were α-Al, CuAl2, AlCu, Al4Cu9, Al2O3. By EDS line scanning, it indicated that the diffusion behavior of elements was different at three regions, compared with the edge region, the interface of the central region was better and the depth of element diffusion is larger, at the pore region, the liquefaction of interlayer was not successfully and the morphology was lamellar. Mechanical properties test showed that the largest shear strength of joint was 4.61 MPa when the duration was 40 min. Key words: Aluminum foams; transient liquid phase bonding; microstructure; element diffusion; shear strength
Effect of the Gamma-Ray Irradiation on the Properties of an Epoxy Encapsulant
Authors: Li Yue Fang , Hu Shou Liang , Zeng Zhi Bin , Liu Xin , Xiang Wei , Xiao Ming Zhu
Published: February 2019

The influence of 60Co gamma-ray irradiation on the chemical compositions and properties of an epoxy encapsulant was investigated. The total irradiation dose varied from 0.1 kGy to 100 kGy with a fixed dose rate of 500 Gy/h. Fourier transform infrared spectra, X-ray photoelectron spectroscopy analysis and discoloration proved the occurrence of oxidation caused by the irradiation. Tg and density remained unchanged owing to the competing effects of irradiation-induced degradation and crosslinking. The tensile strength, impact strength and electrical strength did not decrease distinctly until the irradiation dose reached above 11 kGy. Rubbery coefficient of linear thermal expansion (CTE), relative permittivity and dissipation factor, on the contrary, were more sensitive to the oxidation and increased sharply when the irradiation dose was only 0.1 kGy. Our results suggested that the evolution of CTEs and dielectric properties could affect the long-term application and reliability of the epoxy encapsulant in the irradiative environment.
Defect Engineering in Antimony Telluride Phase-Change Materials
Authors: Wang Yong , Ren Kun , Song San Nian , Song Zhi Tang
Published: February 2019

In the past 20 years, the phase-change memory technology has achieved rapid development, of which alloys along the GeTe-Sb2Te3 pseudobinary line are the most extensively researched materials. In recent years, Sb2Te3-based materials start to attract the attention of researchers. A recent study has shown that the Sb2Te3 (ST) material has a face-centered cubic (Fcc) phase which contains a high concentration of vacancies at low temperature. Due to the poor amorphous thermal stability of ST, the as-deposited film obtained by physical vapor deposition is crystalline (Fcc phase). Therefore, we proposed a vacancy control mechanism, using inert gas Ar to ion implantation of as-deposited ST films, redistributing vacancies in the as-deposited ST films. Through different doses of Ar ion implantation, we obtain amorphous ST materials with different resistivity. We find that after the injection dose reached 1 × 1016 cm-2, the effect of continued increase in the implantation dose on the resistivity of the thin film is negligible. After ion implantation, the transition temperature of the metastable Fcc phase to the hexagonal phase (Hex) is increased, which is beneficial to improve the power consumption and endurance of the device. The ST which is injected with a dose of 1 × 1016 cm−2 Ar ion based phase-change memory cell can perform erasing operation in 100 ns, showing low power consumption potential. Our work provides a new idea and method for the application of future defect control in phase-change memory research.
Characterization and Mechanism Analysis of Growth Bands in Chemical Vapor Deposited ZnS
Authors: Zhang Peng Fei , Li Hong Wei , Yang Hai , Wei Nai Guang , Li Jian Ming , Li Dong Xu
Published: February 2019

In the chemical vapor deposited zinc sulfide, it often appears obvious light and dark growth bands along the growth direction, which will affect the homogeneity of optical properties of CVD ZnS and the efficiency of subsequent heat treatment. X-ray diffraction, Metallographic microscope and SEM were used to detect the crystal structure, grain size and microstructure, and the concentration of Zn and S in different bands was tested by EDTA titration, XRF, ICP and HF-combustion IR absorption spectrometric method. Results: Compared to the normal band, the grain size in the bright band was significantly larger, and the concentration of hexagonal phase in the bright band was lower, while the concentration ratio of Zn and S in the CVD ZnS did not have the regularity in the different bands. Combining with relevant knowledge about characteristics of the deposition process and crystal growth theory, the paper analyzes the formation mechanism of growth bands in CVD ZnS, and find that the main factor is the mutation of the concentration of the reactants in the deposition surface, affect the crystal nucleation rate and growth rate, eventually lead to the different grain morphologies, and even showing up the macroscopic growth bands. Compared with the actual process parameters, we have confirmed it and found out the main causes of mutation of the reactant concentration, this will have important guiding significance to the improvement of product quality in the future.
Microstructure and Mechanical Properties of TiB2/ Al-Si Composites Fabricated by TIG Wire and Arc Additive Manufacturing
Authors: Yang Qing Feng , Xia Cun Juan , Deng Ya Qi
Published: February 2019

Bulky sample was made by using TIG wire and arc additive manufacturing (WAAM) technology, in which Ф1.6 mm filler wire of in-situ TiB2/Al-Si composites was selected as deposition metal, following by T6 heat treatment. The microstructure and mechanical properties of the bulky sample before and after heat treatment were analyzed. Experimental results showed that the texture of the original samples parallel to the weld direction and perpendicular to the weld direction was similar consisting of columnar dendrites and equiaxed crystals. After T6 heat treatment, the hardness of the sample was increased to 115.85 HV from 62.83 HV, the yield strength of the sample was 273.33 MPa, the average tensile strength was 347.33 MPa, and the average elongation after fracture was 7.96%. Although pore defects existed in the fracture, yet the fracture of the sample was ductile fracture.
Influence of Calcination Temperature on Structure and Electrochemical Behavior of LiNi0.83 Co0.11Mn0.06O2 Cathodes for Lithium-Ion Batteries
Authors: Wang Jing , Li Dan Hua , Wang Ran , Chen Shi , Su Yue Feng , Gao Ang , Ji Deng Yue , Wu Feng
Published: February 2019

Nickel-rich layered oxides (Ni ≥60%) are considered as the most promising cathode materials for lithium-ion batteries due to its high energy density and low cost. However, its cycling performance is seriously influenced by the synthesis condition, like the sintering temperature, time and atmosphere. Herein, we investigate different properties of LiNi0.83Co0.11Mn0.06O2 (LNCMO) sintered from 720 to780 °C, and the cathode calcined at 760 °C display the most perfect layered structure and the uniform distribution of primary particles size. Therefore, the LNCMO sintered at 760 °C exhibited the best rate capability of 118 mAh·g-1 at 10 C and the highest capacity retention of 95.44 % after 100 cycles at 1 C. Our results indicate that the cycling performance and rate capability of LNCMO are heavily depended on the sintering temperature.
Preparation of EVA Emulsion Self-Healing Capsules for Concrete and Evaluation of Healing Properties
Authors: Zhang Ying , Du Wei , Li Ying , Yu Jian Ying
Published: February 2019

The self-healing capsule was prepared with paraffin as wall and EVA (ethylene vinyl acetate) emulsion as core through melting condensation dispersion method. The morphology and chemical structure of capsules were characterized by optical microscope and Fourier transform infrared spectroscopy (FTIR). The influence of the stirring rate and emulsion to paraffin ratio on core content of the capsule was investigated. The flexural strength of mortar incorporated with capsules was tested to assess the effect of capsule on mechanical property. In addition, the compressive strength of the mortar was tested before and after self-healing to evaluate the healing efficiency of the capsule. The result showed that the highest core content of the capsule can reach up to 55% under the conditions that stirring rate was 400 rpm and emulsion to paraffin ratio was 1:1. FTIR and optical micrograph of the capsule indicated that the EVA emulsion was contained in paraffin successfully. The dosage of capsules had little effect on mechanical properties of mortar when it was less than 5 wt%. The healing efficiency of mortar for compressive strength was up to 99% at capsule content of 5 wt%, preload of 60% fmax and curing time of 7 days, which meant that the microcracks can be healed efficiently with the EVA emulsion capsule.
A Mathematical Model on Macro-Segregation Formation for Popular Bloom Continuous Casting Process
Authors: Sun Hai Bo , Li Zheng , Li Lie Jun , Nie Bao Hua
Published: February 2019

A segmented 3-D coupled electromagnetic-thermal solute transportation model, aimed to better understand the macro-segregation formation in the strand during a popular continuous casting (CC) process, has been developed. Based on the model validation by industrial tests, the effect of M-EMS and F-EMS running parameters on the segregation distribution were subsequently carried out. It is shown that the simulated solute segregation profile in the W-shape along the casting thickness direction is in a good agreement with the measured profile. In the initial solidification shell with thickness in 0.020 m, the solute segregation degree changes from a positive value to a negative with the increasing distance from strand surface because of the washing effect induced by the impact flow from the nozzle side port and M-EMS. Here, the minimum degree of carbon segregation decreases from 0.976 to 0.875 with the increasing stirring current from 100A to 550A. As the stirring current of F-EMS decreases from 630A to 200A, the minimum segregation degree locating at 0.109 m distance from strand surface increases from 0.805 to 0.967. The carbon segregation degree at the strand center first decreases from 1.10 to the minimum value of 1.06 at the case of 350 A/4 Hz because of the concentration equilibrium for the local decreasing negative segregation induced by F-EMS, and then increases to 1.16 due to the local poor stirring.
Effect of Preparation Process on Surface Quality and Microstructure of Titanium Sheet
Authors: Zhang Ze Yu , Yu Wei , Dong En Tao , Shi Jia Xin
Published: February 2019

At present, domestic cold-rolled titanium sheets have many surface defects, which are significantly different from foreign surface quality. This paper mainly studies the differences in the microstructure and performance of titanium plates GR1 and GR2 imported from Japan and domestic titanium plates TA1, and analyzes the causes of surface defects to solve the problem about TA1. The surface properties of different materials were observed. The mechanical properties of the materials were obtained by room temperature tensile test. The surface roughness of the three materials was tested. The microstructure and composition of the three materials were characterized by SEM, EDS and XRD. The results show that the surface of GR1 and GR2 is brighter and has no obvious chromatic aberration. The surface chromatic aberration of TA1 is larger. The mechanical properties of TA1 are the best. The tensile strength and yield strength of rolling are 325.19MPa and 271.17MPa, respectively, and the lateral direction is 329.19MPa and The roughness of 303.15MPa, GR1 and GR2 is slightly lower than that of TA1. The black area on the surface of TA1 is loose and the oxygen content is high. The pole figure of GR1, GR2 and TA1 are obtained. Keywords: Cold-rolled titanium sheets; Chromatic aberration; Mechanical properties; SEM; Texture
Tubing String Thread Sealing Surfaces Damage Evaluation Based on Acoustic Elasticity Theory
Authors: Wang Jian Jun , Sun Jian Hua , Yang Shang Yu , Feng Yao Rong , Lin Kai
Published: February 2019

During the processing of tubing premium threaded made up, the degree of the thread sealing surface intactness will directly affect the sealing performance of the string. Nevertheless, there are some difficulties to detect the damage of the engaged sealing surface effectively. In the present study the sealing surface damage was judged by the sealing surface contact stress’s relative changes according to the acoustic elasticity theory,. At the same time, the wear defects generated at the tubing sealing surface, during the tubing made up, contrasted with the wear and unworn surface roughness of coupling ultrasonic detected about the sealing surface. The results showed that with the acoustic amplitude evaluated the sealing contact stress was susceptible to the influence of surface roughness of coupling. But the reflection wave with the center frequency on the sealing surface characterization of the contact stress could avoid this problem effectively.
Effect of Lubrication Conditions on the Forming Limit of Deep Drawing of 6061 Aluminum Alloy Sheet
Authors: Wang Yan Qi , Cheng Yong Qi , Zhang Peng , Luo Gan , Li Peng Bin , Jiang Kui
Published: February 2019

With the development of lightweight vehicles, aluminum alloy sheets are increasingly used in the automotive field. However, the aluminum alloy sheet has poor forming performance at room temperature. Therefore, how to improve the sheet metal forming performance of aluminum alloy sheet has become one of the current research hotspots. In this paper, the effects of different lubricants on the deep drawing forming properties of 6061 aluminum alloy sheets were studied by cupping experiments. The effects of lubricants on the deep drawing of sheet metal forming and the wall thickness of cups after deep drawing were explored. The results show that under the condition of drawing speed of 3MPa and 200mm/min, the ultimate drawing ratio of the sheet under oil lubrication is 1.92, and the PTFE film is 2.16. Grease and graphite lubrication are respectively 2.12 and 2.03, using PTFE film lubrication can increase by about 10% contrast with the oil lubrication. The measurement of the wall thickness of the cup under the forming limit state shows that the position with the largest reduction rate appears in the rounded transition zone, and the wall portion of the cylindrical member increases with the height of the wall, and the thickness from the bottom of the cup to the bottom of the cup. The edges all show a trend of decreasing first and then increasing.