bluuebunny/crossref_metadata_2025 huggingface dataset:
Le département de l’Eure sous le Directoire
Authors: André Goudeau
Published: August 2018

Après la Terreur, Incroyables et Merveilleuses tenaient le haut du pavé à Paris, formant une société frivole, dominée par une minorité de parvenus enrichis trop vite. Mais qu’en était-il en province et particulièrement en Normandie entre 1794 et 1800 ?

Proche de Paris, le département de l’Eure allait-il se reconnaître dans le régime institué par la Constitution de l'an III ? Héritier des sociétés populaires, le jacobinisme, appuyé par les deux frères Lindet, conventionnels montagnards originaires de Bernay, était-il en mesure de peser sur la vie politique locale ?

L’Eure, se trouvant aussi, par les cantons bocagers du pays d’Ouche, en limite de l’Ouest rebelle et chouan de la Normandie orientale, fut affecté par la chouannerie normande, relayée par le brigandage des « chauffeurs » de la bande à Robillard. L’administration du département et le commissaire Crochon durent faire face à cette « malveillance ». Tâche rendue d’autant plus difficile qu’entre l’an IV et l'an VIII, leur « républicanisme » était contesté par les néo-jacobins qui se réunissaient au sein des cercles constitutionnels et s’exprimaient dans le Bulletin de l’Eure du journaliste Touquet.

Parallèlement à leurs constants efforts pour assurer le maintien de l’ordre, les administrateurs départementaux, s’appuyant sur les municipalités de canton, cherchèrent à développer une culture républicaine, soutenant notamment les efforts de Rever pour faire de l’école centrale d’Évreux un établissement scolaire innovant sur le plan pédagogique. Il fallait également organiser de fréquentes fêtes civiques et encourager les cultes révolutionnaires pour concurrencer un catholicisme en crise, dans un diocèse où le clergé constitutionnel, désemparé par l’abdication de l’évêque Lindet, tentait néanmoins de se réorganiser.

Cet ouvrage présente les mutations intervenues dans le département entre Thermidor et Brumaire. À travers l’exemple de l’Eure, il s’agit de montrer que le Directoire, ce régime mal-aimé, a toutefois présenté certaines innovations, contribuant à préparer les futures expériences républicaines de la France du xixe siècle.
Les Précurseurs de l’oralité scolaire en Europe
Authors: Langlois Roberte
Published: August 2018

« Quand on sait, on se tait ! » : cette injonction paradoxale, que l'on peut aujourd'hui encore entendre dans une salle de classe, montre le rapport ambigu qu'entretient le couple parole et savoir au sein du système éducatif français. Cet ouvrage éclaire la question de l'oralité scolaire, point aveugle de la recherche en éducation, à travers l'histoire des idées éducatives.

En soulevant la question de l'héritage républicain et plus largement, en mettant à jour un réseau de précurseurs européens de l'éducation dont l'idéal est centré sur le concept de parole vivante, cet ouvrage propose, à l'échelle européenne, une réflexion sur les enjeux et la dimension anthropologique de l'oralité scolaire.
Histoire des institutions de la vie politique et de la société françaises de 1789 à 1945
Authors: Bouveresse Jacques
Published: August 2018

Ce manuel d'histoire des institutions présente deux particularités :

Il prétend d'abord effacer la frontière classique entre les matières relevant du droit public (organisation de l'État et de l'administration) et celles qui tiennent au droit privé (famille, travail, propriété). Séparation dont la critique est passée en lieu commun, mais qui, dans les ouvrages rédigés à l'usage des étudiants en droit, est encore et toujours strictement maintenue.

La formule du mémento a été délibérément écartée. Pas question pour nous d'accabler la mémoire du lecteur, de l'égarer dans la broussaille des détails, de multiplier les énumérations sans substance et sans interprétation. Les faits, les événements, les institutions, les dates viennent simplement à l'appui d'une démonstration : celle qui consiste à mettre en évidence la poussée au cours de ces deux siècles (1750-1945) d'une démocratie à la fois raisonnable et exigeante, opposée à l'hydre constamment renaissante de l'oligarchie, lutte éternelle qui est de l'essence même de la politique.
L'Intendant de Rouen
Authors: Pigeon Jérôme
Published: August 2018

Les intendants rouennais n'ont guère, jusqu'à présent, retenu l'attention. Il en est de même du contentieux fiscal dévolu aux commissaires départis dans les généralités situées en pays d'élections. À ce double titre, l'activité de l'intendant de Rouen, juge du contentieux fiscal au xviiie siècle offrait un terrain propice à un vaste champ d'étude.

Entouré d'un personnel peu nombreux mais de qualité, l'intendant de Rouen vide avec application et modération le contentieux des impôts directs et indirects qui lui est soumis. Il se révèle être un véritable juriste, le plus souvent respectueux de la règle de droit.

Contrôlés scrupuleusement par le Conseil du roi, juge d'appel de ses ordonnances, l'intendant de Rouen entre parfois en conflit avec le pouvoir royal en raison de son attitude conciliante envers les contribuables.

On est loin en somme de l'arbitraire et des despotes fustigés par les cours souveraines au xviiie siècle et par les cahiers de doléances en 1789.
L’évidence du Dieu caché. Introduction à la lecture des Pensées de Pascal
Authors: Frigo Alberto
Published: August 2018

Dans les Pensées, Pascal met toutes les ressources de l'éloquence au service d'une argumentation qui traque inlassablement le vrai. Le raisonneur implacable ne se distingue pas de l'écrivain au sommet de la maîtrise de son art. L'idée apparaît intimement liée à la forme qui l'exprime, le tout aboutissant à un équilibre qui n'a guère d'égal dans l'histoire de la pensée européenne. D'où la force des Pensées, qui ne cessent de charmer et qu'on ne se lasse jamais de citer et d'admirer. Mais aussi la difficulté d'un texte dont la parfaite clarté risque souvent de masquer l'extraordinaire richesse et complexité qu'une masse prodigieuse de commentaires et d'éditions s'évertue à éclaircir depuis presque quatre siècles.

Cette introduction s'efforce d'offrir au lecteur une présentation exhaustive et détaillée des Pensées qui, au fil d'une analyse serrée du texte (presque un véritable commentaire suivi) explicite les enjeux théologiques et philosophiques de l'argumentation orchestrée par Pascal et définit les éléments marquants du style de son écriture.
La Cour de justice précise les conditions de bénéfice de la protection renforcée contre l’éloignement
Authors: Rouy Mathieu
Published: August 2018

L’arrêt rendu par la Grande Chambre de la CJUE le 17 avril 2018 laisse son lecteur perplexe. La Cour de justice était amenée à préciser les conditions de bénéfice de la protection renforcée contre l’éloignement prévue à l’article 28, paragraphe 3, de la directive 2004/38. Si la Cour estime que le droit de séjour permanent est un préalable indispensable à une telle protection, elle estime, toutefois, que l’emprisonnement ne prive pas automatiquement le citoyen du bénéfice de celle-ci.
Preparation and Characterization of Carbon Nanotubes/Al2O3 Inorganic Hybrid Material - A Bio-Inspired Poly(Dopamine) Approach
Authors: Zhao Wen , Wang Wen Cai , Lu Yong Lai , Zhang Li Qun
Published: August 2018

Carbon nanotubes/alumina (CNTs/Al2O3) nanocomposites were prepared by the poly (dopamine) assisted chemical liquid phase deposition (CLPD). The poly (dopamine) layers were firstly coated on the CNTs surface uniformly by the self-oxidative polymerization of dopamine in mild aqueous solution and then the Al2O3 nanoparticles formed on the poly (dopamine) coated CNTs surface by the CLPD. The hydrophilic poly (dopamine) layers on the CNTs surface can improve the dispersion of CNTs in aqueous solution. Moreover, it can be used as a key linker between the CNTs and Al2O3 because of the nitrogen-containing group in poly (dopamine) could coordinate with Al3+ ions. The as-prepared poly (dopamine) coated CNTs and CNTs/Al2O3 nanohybrids were characterized by X-ray photoelectron spectroscopy (XPS), X-radial diffractometer (XRD) and high resolution transmission electron microscopy (HRTEM). These results showed that the poly (dopamine) layers were coated on the surface of CNTs uniformly, and the Al2O3 nanoparticles embellished with the poly (dopamine) coated CNTs surface. Compared with pristine NR composites, the thermal conductivity of the as-prepared NR/CNTs@Al2O3 composites increased 17%.
Microstructures and Reaction Properties of Ti/Ni, Ti/Al and Ni/Al Multilayer Films
Authors: Ma Ying , Li Hong , Yang Lin Pai , Hu An Ming
Published: August 2018

Reactive multilayer thin films are well-defined heterogeneous nanostructured energetic materials which can release chemical energy through a self-sustainable reaction. They have attracted intense interests due to potential applications in diverse fields such as joining, igniters, and high energy density power sources. In this paper, Ti/Ni, Ti/Al and Ni/Al multilayer films were prepared by magnetron sputtering. The reaction kinetics, microstructure and phase variation of these free-standing films are comparatively investigated. During slow heat reaction, the reaction products of reactive multilayer Ti/Ni nanofoils change from B2-TiNi austenite phase into TiNi3, illustrating an evolution of the phase transformation during reaction. These intermediate phases are also identified by slow heating and quenching. The fast speed imaging exhibits that the front speed is 0.47m/s, 0.8m/s and 3m/s respectively for as-deposited Ti/Ni, Ti/Al, and Ni/Al films. Differential thermal analysis yields that the corresponding releasing heat is 551.44 J/g, 434.18 J/g, and 562.5 J/g for these three composites. The theoretical minimum multilayer thickness for melting a tin solder layer has been calculated on the base of these characterizations, which proved the application potential of joining using the as-deposited film.
Crack Reduction in Tabbing and Stringing Processes for Solar Cells
Authors: Kongwiriyaphaisan Atcharapha , Tangwarodomnukun Viboon
Published: August 2018

Wafer cracking is considered to be an important loss in solar cell manufacturing as it crucially affects the production yield as well as the efficiency of solar cells fabricated. There is a certain chance of cracking in wafer when the substrate undergoes some thermal and/or mechanical loads during its fabrication. This research therefore aims to decrease the solar cells cracking in tabbing and stringing processes as the two processes are responsible for a great number of cracks in the substrate. A set of experiments was performed in this study, where soldering temperature and time were tested and the amount of cracks in solar cells was quantified. The findings showed that the use of 185°C soldering temperature with the soldering time of 1,200 ms can reduce the number of cracks in the tabbing and stringing of silicon solar cells. With this setup, the adhesion force between tabbing ribbons and substrate surface can also be promoted, thus preventing the delamination problem in the cell panels.
Metakaolin Based Geopolymer from Thailand as an Adsorbent for Adsorption of Multi- and Mono- Cations from Aqueous Solution
Authors: Onutai Sujitra , Kobayashi Takaomi , Thavorniti Parjaree , Jiemsirilers Sirithan
Published: August 2018

Waste management and water quality are two main problems nowadays. Geopolymer material has efficiency for adsorbing the ions from wastewater. In this research, the metakaolin based geopolymer was studied and used as an adsorbent to remove heavy metal ions. Moreover, the factors which affect adsorption process of heavy metals on geopolymer materials were investigated. The kaolin as used in this research was from Thailand. The metakaolin geopolymer was synthesized by mixed raw materials with an alkaline solution. The metakaolin geopolymer was washed and sieved through 100 mesh. The produced metakaolin geopolymer powder was used as an adsorbent. The XRD results showed a highly amorphous structure in obtained metakaolin geopolymer. Moreover, the BET surface area of metakaolin and geopolymer particles were 9.83 m2/g and 20.36 m2/g, respectively. The parameters of adsorbent amount, initial pH, time of shaking, temperature and initial metal ions concentration on the removal potential of geopolymer were studied. In addition, the multi-and mono-cations solution were demonstrated to compare the efficiency of each heavy metal ions. The results showed that the amount of Pb2+, Cu2+, Cd2+, and Ni2+ions adsorbed onto metakaolin geopolymer increased with an increasing contact time, pH, temperature and amount of geopolymer. It is concluded that Pb2+, Cu2+, Cd2+, and Ni2+ions in aqueous solution are efficiently removed by metakaolin geopolymer which could be applied as a low cost and good alternative for wastewater treatment.
Lead (II) Removal from Contaminated Soils by Electrokinetic Remediation Coupled with Modified Eggshell Waste
Authors: Ribeiro André , Mota André , Soares Margarida , Castro Carlos , Araújo Jorge , Carvalho Joana
Published: August 2018

Electrokinetic remediation deserves particular attention in soil treatment due to its peculiar advantages, including the capability of treating fine and low permeability materials, and achieving consolidation, dewatering and removal of salts and inorganic contaminants like heavy metals in a single stage. In this study, the remediation of artificially lead (II) contaminated soil by electrokinetic process, coupled with Eggshell Inorganic Fraction Powder (EGGIF) permeable reactive barrier (PRB), was investigated. An electric field of 2 V cm-1was applied and was used an EGGIF/soil ratio of 30 g kg-1 of contaminated soil for the preparation of the permeable reactive barrier (PRB) in each test. It was obtained high removal rates of lead in both experiments, especially near the cathode. In the normalized distance to cathode of 0.2 it was achieved a maximum removal rate of lead (II) of 68, 78 and 83% in initial lead (II) concentration of 500 mg-1, 200 mg-1 and 100 mg-1, respectively. EGGIF (Eggshell Inorganic Fraction) proved that can be used as permeable reactive barrier (PRB) since in all the performed tests were achieved adsorptions yields higher than 90%.
Study on Densification Behaviour under Cold Forging of Sintered High Carbon Alloy Steels
Authors: Rajeshkannan Ananthanarayanan , Shanmugam Subramaniam
Published: August 2018

Densification behaviour of sintered Fe-0.8%C-1%Si-0.8%Cu powder metallurgy steel under the influence of two different aspect ratios subject to cold forging is studied in the present investigation. The critical evaluation of cold deformation exercise revealed that induced strains are linearly contributing to enhance densification till the specimen fracture; however overall resistance to deformation of material is exhibiting in three different responses with respect to improvement in densification. That is at initially, high resistance to deformation followed by high kinetics of deformation and finally exhibiting little resistance against overall deformation. Although, the aforementioned criteria is common for both the aspect ratios, the applied deformation is little homogeneous when aspect ratio is less that directly contributes to enhance the rate of attainment of densification as little faster in the later stage of densification on the other hand the higher aspect ratio preform is bit non-linear in nature and retards stress in the later stage.
Precipitate Phases in Normalized Ferritic/Martensitic Steel P92
Authors: Xu Zhi Qiang , Shen Yin Zhong , Zhu Peng Cheng , Liu Wen Wen
Published: August 2018

Precipitate phases in the P92 F/M steel after normalization at 1323 K (1050 °C) for 30 min followed by air cooling to room temperature have been investigated by transmission electron microscopy (TEM). Three types of phases consisting of M3C, MX and M2C have been identified. Needle-like Fe-rich M3C carbide, (Fe0.87Cr0.13)3C, has a simple orthorhombic lattice, and a size of 7-18 nm in short axis and 73-190 nm in long axis. Sphere-shaped Nb-rich MC carbide with a f.c.c. crystal structure has a chemical formula of about (Nb0.69V0.15Fe0.1Mo0.06)C and a size of 12 to 88 nm in diameter. Large-sized Fe-rich M2C phase exhibits a block-like shape, and has a hexagonal crystal structure. TEM examination indicated that the number density of both the Fe-rich M3C carbide and Nb-rich MX phase is higher than Fe-rich M2C carbide phase.
Rolling Contact Fatigue Life of 13Cr-2Ni-2Mo Stainless Steels which are Surface Treated by Induction Heating (IH) and Wide Peening Cleaning (WPC)
Authors: Yamada Takuto , Mizobe Koshiro , Kida Katsuyuki
Published: August 2018

A new surface treatment, wide peening cleaning (WPC), was developed to improve fatigue strength of steels using shot peening and sandblast technologies. The combination of induction heating (IH) and WPC is expected to introduce higher compressive stress on the steels than single IH or single WPC. We investigated effect of IH and WPC on rolling contact fatigue life of 13Cr-2Ni-2Mo stainless steel. Vickers hardness and residual stress measurements, and RCF life evaluation using the Weibull distribution were carried out. It was found that the residual stress was introduced by WPC near the surface to improve life fatigue
Research on Constitutive Relation of Metals under High Strain Rate
Authors: Guo Jian , Yang Lian Fa , Ma Jian Ping
Published: August 2018

The deformation behavior of materials under high strain rate environment is often accompanied by complex physical conditions such as high temperature, high pressure and shock waves. In order to describe the deformation behavior of materials accurately, the external extreme conditions and internal micro-deformation mechanisms of the material must be considered fully. The constitutive relationship of materials is related to the relationship between stress and strain, strain rate, temperature, deformation history, etc. Different constitutive models are based on different conditions and assumptions. This paper summarizes the microscopic deformation mechanisms, constitutive models and physical test methods of the deformation behavior of metals under high strain rate. These three aspects are interrelated and inseparable to explain the deformation behavior of metals under high strain rate.
Determination of Material Property for Non-Pneumatic Tire Spokes by Inverse Method
Authors: Rugsaj Ravivat , Suvanjumrat Chakrit
Published: August 2018

The radial spokes of non-pneumatic tire have been developed to absorb impacts. In order to obtain its property for the further developments, it had to cut into the curve beam specimens. The 3-point bending was selected to test referring to ASTM D790. Subsequently, the finite element method was employed to simulate the 3-point bending test of specimens. The inverse method was used to determine the modulus of elasticity for specimen material. The gradient based on optimization scheme was used to optimize the modulus of elasticity by the input and output condition which was the vertical deflection and force, respectively. The optimized process was terminated at the desirable force tolerance of 0.00071 N. The elastic modulus of spoke was implemented in the finite element model of the 3-point bending test. There was found that the simulation result of vertical displacement obtained an average error of 4.87% by comparing with physical experiment.
Improvement Filler-Rubber Interaction and Mechanical Properties of Silica/NR Vulcanizates by Using Masterbatch Processing
Authors: Buakhlee Waraphorn , Suwanna Pimsiree , Keawwattana Wirunya
Published: August 2018

Due to the dispersion of silica and reducing filler-filler interaction, the improvement of filler-rubber interaction was enhanced the physical properties of silica/NR compounds. This research was then focused on the production of silica masterbatches with surface treatment by surfactant to enhance the silica dispersion. The silica dispersion examined by scanning electron microscopy (SEM)c and the mechanical properties of vulcanizates prepared from the masterbatches were compared with those prepared by a conventional direct mixing method. The mechanical properties of silica/NR masterbatches exhibited greater modulus, tensile strength and hardness compared to the corresponding conventional mixes. A better silica/NR interaction of silica/NR masterbatch was achieved confirming by higher the bound rubber content and lower Payne effect, leading to the greater mechanical properties.
Failure Observation of 3D-Printed Thrust Bearing Specimens at Cross Section Observations in Dry Conditions
Authors: Mizobe Koshiro , Inagaki Masahiro , Kida Katsuyuki
Published: August 2018

3D printing methods are developing and they have become popular recently. 3D printing can easily make complex and seamless parts, however, there are questions about their strength. In particular, the strength of the places where the lamination layer joins is important. We performed rolling contact fatigue (RCF) tests in dry conditions using 3D-printed bearing race and observed the fracture behavior and cracks. We found that the main crack is related to the stress moving direction.
Application of GTN Model in Tensile Fracture of Pipeline Steel
Authors: Lian Ye Da , Wu Ren Qiang , Zhang Bing , Feng Tao
Published: August 2018

In this paper, the macroscopic mechanical behavior of tensile fracture of X70 pipeline steel is combined with the evolution of mesoscopic pores. The ABAQUS finite element software was used to analyze the variation of pore volume fraction in the tensile failure process of unilateral notched specimens with Gurson-Tvergaard-Needleman (GTN) mesoscopic damage model. Combined with the unilateral notched tensile test and the numerical simulation results, the damage mechanics model of pipeline steel based on void volume fraction is established. The results show that the volume fraction of pores is a mesomechanical parameter based on the damage of the micro-holes in the metallic plastic material, which is a bridge between the mesoscopic damage characteristics and the macro-mechanical parameters. Establishing the damage mechanics model of high strength pipeline steel with hole volume fraction as damage variable can truly reflect the macro-meso-mechanics behavior of X70 pipeline steel during unilateral notching.
Vibration and Floor Impact Sound Isolation Performance in Bubble Deck Slab
Authors: Kim Kyoung Woo , Shin Hye Kyung , Park Jong-Young , Chung Jin Yun
Published: August 2018

The bubble deck slab has been applied to various buildings due to many advantages including the slab load alleviation and structural stability. The bubble deck slab should not only ensure structural stability but also satisfy the performance standards of floor impact sound required legally to be applied to apartments. This study investigated the characteristics of reduction in vibration and floor impact sound in apartments where the bubble deck slab was applied. The measurement results of vibration characteristics showed that the bubble deck slab had a similar natural frequency with that of the solid slab from a frequency (each of 16.7 Hz and 11.1 Hz) where the first mode was formed but the vibration level of the bubble deck slab at the low frequency band (80 Hz or lower), which was affected by the heavy-weight impact sound, was relatively smaller than that of the solid slab. The bubble deck slab showed a comparable or better performance in the insulation of the floor impact sound compared to that of the solid slab.
Bending Behavior of Simply-Supported Sandwich Beams Subjected to Large Deflection
Authors: Xie Zhong You
Published: August 2018

Due to thin skins and soft core, it is apt to local indentation inducing the concurrence of geometrical and material nonlinearity in sandwich structures. In the paper, finite element simulation is used to investigate the bending behavior of lightweight sandwich beams under large deflection. A modified formulation for the moment at mid-span section of sandwich beams under large deflection is presented, and energy absorption performance is assessed based on energy absorption efficiency. In addition, it is found that no local indentation arises initially, while later that increases gradually with loading displacement increasing. The height of the mid-span section as well as load-carrying capacity decreases significantly with local indentation depth increasing.
Degree of Conversion of Three Light-Cured Orthodontic Adhesives
Authors: Wichai Wassana , Nimcharoensuk Kanin , Anuwongnukroh Niwat , Dechkunakorn Surachai , Roongrujimek Pitchaya
Published: August 2018

Introduction: The aim of this in-vitro study was to analyze the polymerization ability of 3 light-cured orthodontic adhesives by determining the degree of conversion (DC). Materials and Methods: Fourier transform infrared spectroscopy (FTIR) was used to evaluate the DC after polymerization immediately, 1 day, 7 days, and 30 days. The adhesives investigated were Transbond XT (3M Unitek, USA), Grengloo (Ormco Corp., USA), and Green Glue (Hangzhou Biomaterials, China). Twelve stainless steel brackets (n=4) were used and the adhesives were cured with Bluephase G2 (Ivoclar Vivadent, Liechtenstein). The data were analyzed by Kruskal-Wallis test for comparing materials and Friedman test for comparing the time periods. Results: The DC values were significantly different among the materials and among the time periods. The highest DC in each period was obtained for Grengloo and the lowest DC was observed for Transbond XT. Thus, there were significant differences between the DC values of Grengloo and Transbond XT in each period. Among the time periods, DC% at T1 (Immediately) and T3 of the material were significantly different. The DC values of all adhesives increased extremely from immediately following curing to 1 day and then slightly increased from 1 day to 7 days. Conclusions: Grengloo showed the highest levels of DC at all tested periods. The percentage values of DC largely increased from immediately following curing to 1 day. This concluded that monomers in orthodontic adhesives kept converting even after completion of photoactivation.
Cytotoxicity of Three Light-Cured Orthodontic Adhesives
Authors: Pudpong Natthasit , Anuwongnukroh Niwat , Dechkunakorn Surachai , Wichai Wassana , Tua-Ngam Peerapong
Published: August 2018

Objective: The aim of this study was to evaluate the cytotoxic effects of three commercial light-cured orthodontic adhesives.Materials and methods: The potential cytotoxic effects of three types of orthodontic adhesives, Grengloo, Green Glue, and Transbond XT, were tested on L929 cell culture. The cell line was grown in 96-well tissue culture plates (1x105cells/mm3). Thin resin discs weighing 0.4, 0.6, 0.8, 0.8, and 0.8 gram of each material were prepared and aged for 1, 3, 6, 8, and 10 days, respectively, in Minimum Essential Medium (MEM) at 37°C with 5% CO2at 100% humidity. Cell viability was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay according to ISO 10993-5: 2009 (E). The differences among the groups was statically analyzed by independent paired t-test (α = 0.05).Results: After 1 day of storage, all adhesive systems showed cytotoxic effects. However, ageing tended to considerably reduce the cytotoxicity of Green Glue. Grengloo was essentially non-cytotoxic day 3 onwards, while Green Glue and Transbond XT exhibited potential cytotoxicity at all times of the experiment. Conclusion: All tested light-cured orthodontic adhesives had cytotoxic potential during the first day. Grengloo had the highest cell viability, whereas, Green Glue had the lowest.
Preparation and Properties of YAG Porous Ceramics via the Casting Method
Authors: Liu Yue , Yang Yan , Chen Wang , Song Jie Guang , He Long , Li Jin Shi , Chen Lin , Guo Song Lin , Qin Yue Ning
Published: August 2018

YAG has many excellent features and therefore has a wide range of applications. Preparation and properties of YAG porous ceramics via the casting method is investigated. Through analysis and discussion, the following conclusions can be obtained. With the increase of the content of foaming agent, in the foaming process of the slurry, bubbles generated by the foaming agent and water are gradually increased, the more pores are left in the body after casting, and when the blowing agent is too much, excessive bubbles are generated, which can lead to a very low strength of the green body and can not be formed and operated later. As the ratio of water to material increases, the porosity of the porous material increases. This is because when the blowing agent is constant, the amount of water required for foaming is constant, and the amount of foam generated is also constant. When the content of foaming agent and the ratio of water to material is both 1, the porosity and compressive strength is better.
Light Burning Condition of Preparing Dolomite Clinker Using Natural Dolomite
Authors: Zhang Wang Nian , Wang Xi Tang , Wang Zhou Fu
Published: August 2018

The influence of the light burning temperature on the sintering property of nature dolomite has been investigated by two-step sintering process in the temperature range 1500 °C to 1600 °C. The resulting bulk densities and apparent porosities of the sintered dolomite samples were examined, and analyzing the sintered dolomite by scanning electron microscopy and X-ray diffraction were performed. The results showed light burned at 850 °C for 3 h, the main phases of the dolomite with 3-5 grain size were MgO, CaO and little CaCO3, and then fired at 1600 °C,the density of sintering dolomite reached to 3.38 g/cm3, the apparent property was 1.2 %, the size of MgO grain up to 3.75 μm . However when dolomite light burned at 1050 °C for 3 h, the main phases were MgO and CaO, and then fired at 1600 °C,the density of sintering dolomite only was 3.30 g/cm3, the apparent property was 2.3 %, the size of MgO only was 3.05 μm .
Effect of SiCp Addition on Microstructure and Mechanical Properties of ZTA Ceramics by Microwave Sintering
Authors: Chen Yong Qiang , Li Sai , Li Wei , Su Ting Ting , Fan Bing Bing , Li Hong Xia , Zhang Rui
Published: August 2018

The effects of SiCp addition on the microstructure and mechanical properties of ZTA ceramics was investigated by microwave sintering. Partially stabilized zirconia（3Y-ZrO2）nanopowder containing SiCp was prepared by microwave pyrolysing precursor which was was achieved by co-precipitation method. The powders of alumina, yttria partially stabilized zirconia containing SiCp were mixed to prepare ZTA ceramics green body by die pressing and cold isostatic pressing and subsequently sintered at the range of 1350°C-1550°C for 30min by microwave. XRD revealed that 3Y-ZrO2/SiC powder contained more tetragonal phase than 3Y-ZrO2 powder which was also confirmed by SEM and particle size distribution. The phenomenon was because of SiCp forming the microwave heating spot that promoted pyrolysis progress when 3Y-ZrO2/SiC powder was prepared by microwave heating. Microstructure showed that the grain of ZTA ceramics had directional growth by microwave sintering. SiCp firstly absorbed microwave that made more uniform sintering of ZTA ceramics and caused local oriented growth of zirconia and alumina. Thus, the bending strength of ZTA ceramics was higher than ZTA without SiCp. The ladder type heating mode of microwave sintering ZTA ceramics reduced relatively sintering time by 20min due to the addition of SiCp.Introduction
Fabrication of Porous Mullite Ceramics with Different Phase of Alumina for Insulation Materials
Authors: Luo Han , Li Yuan Bing , Li Shu Jing , Chen Ruo Yu , Xiang Ruo Fei , Xu Na Na , Wang Qing Heng , Si Ou Yang
Published: August 2018

This paper reports the effects of γ-Al2O3 and α-Al2O3 on the properties of lightweight insulation materials. The phase compositions, microstructure and mechanical properties of lightweight insulation materials are separately investigated by XRD, SEM and tabulate thermal conductivity apparatus methods. The results indicate that the increasing of the amount of γ-Al2O3 is beneficial to improving the bulk density, compressive strength and acid resistance of the fired specimens. The fact negatively impacts on the increasing of the apparent porosity; however, it has no significant effect on the thermal conductivity of specimens. Meanwhile, the studies highlight that when the content of γ-Al2O3 increases, the nucleation and growth of mullite is accelerated at high calcination temperature, which has positive effect on improving the physicochemical properties of lightweight insulation materials. And the γ-Al2O3-free SiO2 glass phase system is guided by theoretical analysis of reaction conditions for non-catalytic system with Factsage modelling.
Mechanical and Thermal Properties of MgAl2O4-Y3Al5O12 Ceramic Composites
Authors: Liu Jiang Bo , Wang Zhou Fu , Liu Hao , Wang Xi Tang , Ma Yan
Published: August 2018

MgAl2O4-Y3Al5O12 ceramic composites were prepared using fused spinel and a Y2O3 micropowder as the raw materials. The microstructure and thermal properties of the composites were characterized by X-ray diffraction, scanning electron microscopy, laser flash diffusivity measurements. The mechanical properties were also determined. MgAl2O4-Y3Al5O12 ceramic composites are composed of spinel and garnet structures. The thermal expansion coefficients of MgAl2O4 and MgAl2O4-Y3Al5O12 ceramics are similar. The measured thermal diffusivity decreases gradually with increasing temperature. Thermal conductivity of the composites is in the range of 3.3-5.8 W∙m-1∙K-1 from 400°C to 900°C.
Fabrication and Characterization of Li4SiO4 Ceramic Pebbles Doped with Y2O3 and Nb2O5
Authors: Wang Man , Xiang Mao Qiao , Zhang Ying Chun
Published: August 2018

Tritium breeder blanket has been considered as one of the most important components of thermonuclear fusion reactor. Recently, Li4SiO4has been regarded as one of the favored ceramics breeders as it exhibits excellent tritium release properties. In order to further improve the comprehensive properties of Li4SiO4pebbles, the grain size and crush load of Li4SiO4pebbles doped with Y2O3and Nb2O5were systematically studied in this work. The results showed that the relative density of Li4SiO4pebbles was increased to 87.2% and the crush load was increased from 43N to 48N when Y2O3doping was used. In view of inhibiting grain growth and increasing the crush load and relative density of Li4SiO4pebbles, the effect of Nb2O5doping was better than that of Y2O3doping.
Modification of the Fiber-Matrix Interface in the Carbon Fiber Reinforced ZrB2- Based Ultra-High Temperature Ceramic Composites
Authors: Zu Yu Fei , Li Jian , Dai Ji Xiang , Sha Jian Jun
Published: August 2018

Carbon fiber reinforced ultra-high temperature ceramic composite (Cf/UHTC) is a typical structural material currently used for aero-engine parts, hot gas valve parts, and thermal protection systems. However, for Cf/UHTC, one of the key issues is that the carbon fibers may be prone to react with the matrix of UHTC during the high-temperature sintering process. This paper mainly focused on restraining the serious fiber-matrix interfacial reaction. The carbon fiber reinforced ZrB2-based composite (Cf/ZrB2-based composite) was selected as the research material in the current work. Some processing methods were adopted to restrain the fiber-matrix interfacial reaction. Microstructure analysis, element distribution, and phase composition were characterized by using scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD), respectively. The results indicated that the matrix/fiber interfacial reaction in the Cf/ZrB2-based composite was closely related to the processing methods.
Spark Plasma Sintering and Characterization of Mixed h-BN Powders with Different Grain Sizes
Authors: Zhai Feng Rui , Lu Min , Shan Ke , Yi Zhong Zhou , Xie Zhi Peng
Published: August 2018

Mixtures of two grades of hexagonal boron nitride (h-BN) powder differing in their grain size and crystallinity were spark plasma sintering in a vacuum. The influences of the mixing ratio of h-BN powders on the densification, microstructure and mechanical properties were investigated in detail. The results show that the smaller grain size, the lower crystallization degree and the higher density and mechanical properties. While the orientation degree of flake h-BN grains can be greatly enhanced by using h-BN powder with larger particle size. As the increasing of nanometer h-BN powder adding amount, the relative density has the same “V” shape changing trends with mechanical properties. In addition, the orientation of boron nitride grains varied widely, and a nearly isotropic material was prepared from a mixture containing 90wt.% nanometer powder.
The Preparation of Cf/ SiC-ZrC Composite Material by Adding SiC and ZrC Powders in Organic Precursors
Authors: Yang Lu Ping , Wang Yang , Jiang Kai , Yang Fang Hong , Wang Yan Yan , Zhou Chang Ling , Liu Fu Tian
Published: August 2018

In this paper, we added inert filler SiC and ZrC powders in an organic precursor solution to prepare Cf/SiC-ZrC composites. The experiments of three different contents of slurry in the process of impregnation and pyrolysis for Cf/SiC-ZrC composites were studied. The microstructure and composition of Cf/SiC-ZrC composites were analyzed by scanning electron microscope (SEM) equipped with EDS. This study shows that the addition of inorganic powders in an organic precursor solution can shorten the period of preparation of the composite material and improve its strength. When the mass fraction of the inert filler is 15% in an organic precursor solution, the density of the composite material can be increased to 1.9 g·cm-3 rapidly in 8 periods of preparation. Meanwhile, the internal structure of the prepared composite material becomes more compact, and its mechanical properties are excellent.
Preparation and Properties of NZP Family Ceramics
Authors: Li Han , Xu Hong Zhao , Wang Yan Yan , Zhou Chang Ling , Liu Rui Xiang , Yang Lu Ping
Published: August 2018

The matrix of NZP family ceramics is natrium phosphate zirconium (for short, NZP) . NZP family ceramics have the designabolity of thermal expansion coefficient, and the average thermal expansion coefficient can be changed from negative value to positive value by means of composition adjustment, thus obtaining zero thermal expansion ceramics with good thermal shock resistance. With NZP family ceramics the thermal stress can be effectively reduced and the thermal properties of materials can be enhanced.Therefore, NZP family ceramics have become a hot topic in materials science community in recent years.The calcium phosphate zirconium powder was prepared by coprecipitation method, and NZP family ceramics were prepared after pressing molding and pressureless sintering. The results show that the compressive strength of the prepared NZP family ceramics is 199 MPa and the thermal expansion coefficient is-0.5×10-6/°C at sintering temperature of 1100°C.
Ablation Behaviors of ZrC-20vol.%MoSi2 Composite Coating under Different Heat Fluxes
Authors: Liu Tao , Niu Ya Ran , Li Chong , Huang Li Ping , Zheng Xue Bin , Ding Chuan Xian
Published: August 2018

ZrC-20vol.%MoSi2 (ZM) composite coating was fabricated by vacuum plasma spray and the ablation resistance was assessed using plasma flame under low (1.94 MW/m2) and high (3.01 MW/m2) heat fluxes, respectively. Results showed that the ultimate surface temperatures of ZM coating were about 2100 °C and 2400 °C, respectively. ZM coating exhibited good ablation resistance at low heat flux, which benefited from the low evaporation of SiO2 and the diffusion of Si derived from MoSi2 decomposition. However, bubble-burst event took place under high heat flux. The different ablation behaviors of ZrC-MoSi2 coating were analyzed, which might contribute to the application of ultra-high temperature ceramic coatings.
Enhanced Bioactivity of Chemically Oxidization-Modified Titanium Alloys
Authors: Wang Ya Ming , Song Yong Fa , Deng Shun Lan , Akiyoshi Osaka , Wang Guang Xin , Yan Yan Fu
Published: August 2018

Anatase-type titanium dioxide oxide layer was formed on the surface of titanium alloy by chemical oxidation. 0.9 um thick anatase was obtained by soaking in a mixed solution of a certain proportion of hydrogen peroxide and hydrochloric acid and then heat treatment. The surface morphology, phase structures and composition of oxide layers were characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). Thickness of titania coating was measured by the ball pit gauge. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) was used to detect the change of Ca ion and P ion concentration in solution. The results showed that anatase layers deposited apatite within 4 days accompanying the decrease of pH when soaked in simulated human body fluid (SBF). Ion exchange between the negative ions and calcium ions in SBF is proposed as the mechanism operative to favor the deposition on apatite.
Structural Evolution and Microwave Dielectric Properties of Ba(Co1/3(Nb1-xW5x/6)2/3)O3 Ceramics
Authors: Wang Zhe Fei , Zhai Chen Yao , Wang Xu Hong
Published: August 2018

Ba(Co1/3(Nb1-xW5x/6)2/3)O3 (0<x≤0.05) (BCWN) microwave dielectric ceramics have been prepared by solid-state reaction method. The microstructure and microwave dielectric properties of BCWN ceramics were investigated systematically in this paper. The results show that the sintering temperature decreases with the substitution of W6+. The Ba(Co1/3(Nb1-xW5x/6)2/3)O3 solid solution is formed with the small substitution of W6+ (x≤0.01). With the increase of x, the impurity phase BaWO4 occurrs and the grains become less homogeneous. Combined with the analysis of X-Ray Diffraction, the cation ordering degree on B-site increases in the sample of x=0.01, which leads to the decrease of the dielectric loss. However, the second phase BaWO4 inhibits the formation of the ordered structure with the reduction of sinterability. Due to the formation of BaWO4, the values of εr and τf of all samples decrease subsequently. The optimized microwave dielectric properties of Ba(Co1/3(Nb1-xW5x/6)2/3)O3 ceramics were obtained in the samples of x=0.01: εr=33.8, Q×f =110761 GHz, τf = -17 ppm/°C.
Effect of L-Cysteine on Photoluminescence of Zns:F Quantum Dots
Authors: Wang Xiao Xuan , Wang Shu Zhen , Duo Shu Wang , Jiang Xing Yu , Li Wen Li , Wu Hao Shuang , Min Wei , Yuan Xue Yan , Chen Zhong
Published: August 2018

ZnS:F quantum dots (QDs) capping with and without L-cys were synthesized by a solid-state method at low temperature, and the influence of L-cys on the properties of ZnS:F QDs were investigated. The crystal structure, surface morphology and luminescent properties of the samples were analyzed by X-ray diffractometer (XRD), transmission electron microscope (TEM), fourier transform infrared (FTIR), photoluminescence spectrometer (PL) and ultraviolet-visible spectrometer (UV-Vis). The results showed that all samples had a zinc blende structure with particle size in the range of 2-6 nm. The emission intensity was significantly enhanced after capping with L-cys, and the strongest luminescence was obtained when the ratio of L-cys/ZnS:F was 0.8:1, and was about 2.5 times of that of ZnS:F QDs. The capping of L-cys increased the grain size of ZnS:F QDs and their water solubility.
Effect of pH on the Properties of BiVO4 by Hydrothermal Synthesis Method
Authors: Liu Xin , Li Jia Ke
Published: August 2018

Bismuth vanadate (BiVO4 ) powders were synthesized using Bi (NO3)3.5H2O and NH4VO3 as raw materials, NaOH and HNO3 for pH adjustment. The samples were characterized by X-ray diffraction ( XRD ), scanning electron microscopy (SEM ) and UV-vis diffuse reflectance spectra techniques. The results show that the pH of precursor solution has great effect on the composition and morphology of products. Synthetic product was BiVO4 with two kinds of crystal shape ( monoclinic and tetragonal ) with pH of 3; synthetic product was pure monoclinic phase BiVO4 when the pH is between 5-9. Whereas, V2O5 and Bi2O3 appeared when the pH was 11; synthetic product was a mixture of V2O5 and Bi2O3 with pH of 13, and BiVO4 don’t exist. The photocatalytic activity was evaluated by the degradation of methylene blue solution. It is shown that the synthetic sample has the best photocatalytic ability with pH of 5. The degradation of methylene blue reaches 84.7% when irradiated for 240 min by high pressure mercury lamp, and the sample synthesized at 13 for pH has strong adsorption capacity and poor photocatalytic ability.
Enhanced Photocatalytic Activity of Cu1.8Se/CuAgSe for Organic Pollutants under Visible and Near-Infrared Light
Authors: Qiao Li Na , Tang Ming Rui , Gang Yong Yun , Xu Hao Min , Lin Yuan Hua
Published: August 2018

The Cu1.8Se/CuAgSe nanostructure was synthesized by a simple two-step process. Starting with the template of cubic Cu1.8Se nanoplate by precipitation method, Cu1.8Se/CuAgSe nanostructure and ternary CuAgSe were prepared through a rapid ion exchange reaction using various amount of AgNO3 at room temperature. The as-prepared samples were analyzed by XRD, SEM and DRS. It was found that Cu1.8Se/CuAgSe heterostructure and the pure CuAgSe phase were formed without changing the morphology, and these samples had efficient light absorption from UV light to near-infrared light region. Photocatalytic properties of these samples were evaluated by the degradation of Congo red under visible and near-infrared light. The Cu1.8Se/CuAgSe nanostructure showed enhanced photocatalytic activity due to the lower recombination of charge-carrier in the photodegradation process.
The Synthesis and Application of the Hollow Mesoporous SiO2/ Dense SiO2/Fe3O4 Composite Particles
Authors: Ma Zi Jun , Li Qun Yan , Ma Kai Rui , Sun Shi Bing , Wei Qi , Cui Su Ping
Published: August 2018

The hollow mesoporous SiO2/dense SiO2/Fe3O4composite particles with different pore sizes were prepared by a multistep coating technique. TEOS as a silicon source, and P123 were combinated with co-surfactant CTAB as template to coat mesoporous on the dense SiO2/Fe3O4composite particles. The influence of the pore diameter in the composite particles on the laccase immobilization amount in the composite particles and the catalytic efficiency of 2,4-dichlorophenol on hollow composite particles were researched in detail. When the pore diameter of the hollow composite particles was 4.30 nm, the laccase immobilization amount reached the maximum (234 mg/g). The pH was within 3 ~ 8 range, and the activity of immobilized laccase was obviously higher than that of free laccase molecule. And the relative activity of immobilized lactase was highest when pH was 4. When the temperature was within 303K ~ 353K, the immobilized laccase had higher relative activity than free laccase and the activity of immobilized laccase still remained 28%. The removal rate of 2,4-dichlorophenol of immobilized laccase in the composite particles was about 80%.
Hydrothermal Method Preparation of Flower-Like Ce-Doped ZnO as an Efficient Photocatalyst
Authors: Ai Jian Ping , Liao Wei Xiu , Luo Shan Shan , Zhou Tao , Cheng Li Hong , Chen Zhi Qin , Chen Yan , Yang Yan Ling , Li Wen Kui
Published: August 2018

Well-crystalline flower-like Ce-doped ZnO were synthesized by facile and low-cost hydrothermal method. The prepared samples were characterized by a variety of characterization techniques such as X-ray diffraction (XRD), Fourier Transform Infrared Spectrometer (FT-IR), UV-visible spectroscopy, scanning electron microscopy (SEM) combined with energy dispersive X-ray diffraction (EDX), to study the crystal structure, optical properties, surface morphology and chemical composition. It was observed from XRD and FT-IR results that synthesized powder had hexagonal wurtzite structure. The photocatalytic activities of the prepared samples were evaluated by photocatalytic degradation of methyl orange (MO) and Rhodamine B (RhB) under UV light irradiation. The results showed that the Ce-doped ZnO photocatalyst with 0.5% cerium exhibited highest photocatalytic activity compared to other samples. The enhanced photocatalytic activity could be attributed to inhibition of the electron-hole pair’s recombination.