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Morphology control of gold nanoparticles on glass surface realized by electric field assisted dissolution method

Zou Zhi-Yu,Liu Xiao-Fang,Zeng Min,Yang Bai,Yu Rong-Hai,Jiang He,Tang Rui-He,Wu Zhang-Ben,

物理学报 , 2012,
Abstract: Noble metal nanoparticles have potential applications in photonics, catalysis, and bio-labeling, owing to their much unique optical properties and surface activities. Monodisperse spherical Au nanoparticles with sizes in a range of about 60-80 nm are formed on the glass surfaces via ion sputtering and follow-up heat treatment. At an appropriate temperature, the electric field assisted dissolution process of Au nanoparticles is realized by the strong direct current electric field in step-like feature. In the different color areas of glass surface, it can be found that the original spherical Au nanoparticles are dissolved into the particles with the shape of a lunar eclipse. From surface plasmon resonance absorption properties and scattering electron microscopy images of Au nanoparticles in the different color areas, the influence of experimental condition on property of gold nanoparticle is demonstrated. From the current-voltage characteristics in electric field assisted dissolution experimental process, the physical process of Au nanoparticle dissolution under strong direct current electric field is analysed: the tunneling process of ejected electrons from Au particles to the anode starts, then followed by transfer process of Au cations to the glass matrix and the combination process of electrons from cathode with a positive charge Au particles. The physical mechanism of morphology control of Au nanoparticles realized by electric field assisted dissolution method is discussed in detail.
Comparison of the sealing ability of different types of glass ionomer cements in temporary restoration
Thiago Vitelli Vasco dos Santos,Cleber Keiti Nabeshima,Mariana Cavatoni,Maria Leticia Borges Britto
RSBO , 2012,
Abstract: Introduction: Glass ionomer cement has been used for temporary restoration; however, several formulations are available. Objective: The aim of this study was compare the linear leakage of different types of glass ionomer cement – R, F, N and C. Material and methods: Forty-four third molars were used and prepared with standardized class I cavity preparations. By using gutta-percha, the cavity height was standardized in 5 mm. The samples were divided into 4 experimental groups (R, N, F and C), and 2 control groups (positive – not restored, and negative – restored using resin). The teeth were waterproofed and immersed in 2% methylene blue. After 7 days, they were sectioned and the measurement of the dye leakage was performed by stereomicroscopy (40X) using a calibrated periodontal probe. Results: Data were analysed by Kruskal Wallis and Dunn tests. There was statistically significant differences (p = 0.002) between R and C, and R and N glass ionomer groups. C and N glass ionomer groups were similar. F glass ionomer group was similar to all other groups. Conclusion: It can be concluded that different types of glass ionomer formulations can influence the peripheral sealing of the restorative material. R glass ionomer was the most effective, while C and N glass ionomers were the least ones.
Evaluation of sealing ability of Glass Ionomer, white MTA, and Super EBA as coronal plug in intra coronal bleaching
M Zare Jahromi,M Feyzian Fard,MR Malekipour,M Kondori
Journal of Isfahan Dental School , 2007,
Abstract: Introduction: External resorption of cervical area is one of the worst side effects of bleaching in non vital teeth. One method for inhibition is placing a coronal plug into the canal's entrance. Therefore sealing ability of 3 materials including Super EBA, MTA and Glass Ionomer were examined in this research as coronal plug before bleaching procedure.Methods and Materials: Seventy single canal anterior teeth were chosen by simple randomization. After access cavity preparation, the canals were cleaned and shaped. Five teeth were used as positive control and five as negative control. Other sixty teeth were filled with gutta-percha and sealer using lateral condensation method. In the next step, 3mm of gutta percha was removed from the coronal part and a thickness of 2mm of one of the materials (GI, Super EBA, MTA) was placed as coronal plug. Then the teeth were bleached 3 times with an interval of 72h, using Sodium Perborate and 3% H2O2.Then the access cavities were completely cleaned and filled with 2% methylene blue for 24h. The sample teeth were washed, dried and sectioned and dye penetration was measured using magnifying glass and cullies. Data was analyzed by ANOVA and LSD tests.Results: The average dye penetration was 3.23mm in MTA, 5.42mm in Super EBA and 1.76mm in GI group (p value = 0.018).Conclusion: Based on the results obtained from this study, glass ionomer was the best material for secondary seal before bleaching. Sealing ability of MTA was lower than GI, and of Super EBA was the least.Key words: Coronal plug, Glass ionomer, Leakage, MTA, Super EBA
Prestress measurement during glass-metal sealing based on a fiber sensor

- , 2018, DOI: 10.16511/j.cnki.qhdxxb.2018.21.017
Abstract: 为实现对玻璃中预应力的测量,该文提出了一种基于光纤传感的玻璃封接预应力测量方法。将光纤Bragg光栅传感器植入封接玻璃预留孔中,加热使玻璃熔融,再冷却固化从而使光纤传感器、玻璃、金属同时烧结在一起。通过光纤传感信号的实时监测,实现了对封接温度的实时测量。通过光纤传感信号的变化,计算出了封接玻璃中测量路径的轴向压缩应变,结合有限元分析得到玻璃中的全局应力分布。实验结果表明:光纤传感器可实现对封接过程温度和应力的监测,以玻璃中预应力为指标可以实现对封接工艺的优化。
Abstract:An optical fiber sensing method was developed for prestress measurements of glass-metal seals. A fiber Bragg grating sensor was embedded in a hole in the sealing glass. The glass was then heated to melting, cooled and solidified so that the optical fiber sensor, the glass and the metal shell were sealed together. The fiber sensor gave real-time measurements of the sealing temperature during the sealing. The changes of the Bragg wavelength were used to measure the axial strain along the measurement path in the glass seal. The global stress distribution in the glass was then calculated by a finite element analysis. Tests show that the fiber sensor can monitor the temperature and stress during the sealing process and an optimized sealing process can be achieved by using prestress measurements in the glass as an indicator.
Present Status and Development Trends of Sealing Materials for Solid Oxide Fuel Cells

ZHU Qing-Shan,PENG Lian,HUANG Wen-Lai,XIE Zhao-Hui,

无机材料学报 , 2006,
Abstract: Sealing was identified as one of main technical barriers in the commercialization of advanced planar solid oxide fuel cells(SOFCs). Much attention has therefore been paid to SOFC sealing. In the present paper, current status of SOFC sealing, including the functions of sealing, sealing strategy, types of sealing, sealing materials (metal alloys, braze, mica, glass, glass ceramics, etc.), was reviewed. Future trends about SOFC sealing were discussed.
Mean Field Model of a Glass  [PDF]
Victor Dotsenko
Physics , 2002,
Abstract: In this paper we propose a simple mean-field "toy" model for the liquid-glass phase transition. This is the system of $N$ point-like particles confined in a finite volume of a $D$-dimensional space interacting via infinite-range oscillating potential. In the framework of the replica approach it is shown that such a system exhibits the phase transition between the high-temperature liquid phase and the low-temperature glass phase. This phase transition is described in terms of the standard one-step replica symmetry breaking scheme.
Microwave assisted synthesis using catalysts on controlled pore glass carriers  [PDF]
Janine Freitag,Monika Hermann,Matthias Nuchter,Bernd Ondruschka
Optica Applicata , 2005,
Abstract: Due to their beneficial features, TRISO -controlled pore glass carriers are very well suited for the preparation of catalysts for application in technically important reactions, e.g., C–C-coupling processes of the Suzuki-reaction type or highly selective hydrogenations. We describe here the development of first experiments with an effective and sustainable catalyst system in microwave-assisted syntheses. An essential advantage of porous catalysts prepared using microwave conditions is their reusability after reaction for further processes. The results are promising as regards the inception of a scalable reaction system for application in synthetic reactions using microwave energy.
Study on Effect of Ultrasonic Vibration on Grinding Force and Surface Quality in Ultrasonic Assisted Micro End Grinding of Silica Glass  [PDF]
Zhang Jianhua,Zhao Yan,Zhang Shuo,Tian Fuqiang,Guo Lanshen,Dai Ruizhen
Shock and Vibration , 2014, DOI: 10.1155/2014/418059
Abstract: Ultrasonic vibration assisted micro end grinding (UAMEG) is a promising processing method for micro parts made of hard and brittle materials. First, the influence of ultrasonic assistance on the mechanism of this processing technology is theoretically analyzed. Then, in order to reveal the effects of ultrasonic vibration and grinding parameters on grinding forces and surface quality, contrast grinding tests of silica glass with and without ultrasonic assistance using micro radial electroplated diamond wheel are conducted. The grinding forces are measured using a three-component dynamometer. The surface characteristics are detected using the scanning electron microscope. The experiment results demonstrate that grinding forces are significantly reduced by introducing ultrasonic vibration into conventional micro end grinding (CMEG) of silica glass; ultrasonic assistance causes inhibiting effect on variation percentages of tangential grinding force with grinding parameters; ductile machining is easier to be achieved and surface quality is obviously improved due to ultrasonic assistance in UAMEG. Therefore, larger grinding depth and feed rate adopted in UAMEG can lead to the improvement of removal rate and machining efficiency compared with CMEG. 1. Introduction Expanding requirements of microproducts with features and structures at microscale and nanoscale, such as micro optical system, micro robot, micro motor, and fuel injection nozzle, presents stimulation and challenges to micromachining technology [1, 2]. Machining of micro parts made from nonferrous metals and other materials, which are not difficult to machine, can be reliably achieved by microturning, micromilling, microdrilling, and so forth [2]. However, there are only limited methods existing for the process of 3D micro components of hard and brittle materials. Microgrinding is one of the most promising processing technologies in this field. Ramesh et al. [3] conducted high-table-reversal-speed microgrinding tests on different hard and brittle materials, in which fine slots with 0.1?mm width and high aspect ratio of 15 were produced. The lowest surface roughness obtained of WC, Al2O3, and BK7 are 0.16?μm, 0.32?μm, and 0.52?μm, respectively. The lowest average surface roughness of 12.97?nm was achieved in Rahman’s experiment [4], in which microgrinding of BK7 glass was carried out using micro-EDM-fabricated PCD tool. There are many challenges that lie in microgrinding. High grinding forces in microgrinding result in high heat generation and rapid microwheel wear [3, 5, 6]. In addition, according
Ising spin glass transition in magnetic field out of mean-field  [PDF]
L Leuzzi,G. Parisi,F. Ricci-Tersenghi,J. J. Ruiz-Lorenzo
Physics , 2008, DOI: 10.1103/PhysRevLett.103.267201
Abstract: The spin-glass transition in external magnetic field is studied both in and out of the limit of validity of mean-field theory on a diluted one dimensional chain of Ising spins where exchange bonds occur with a probability decaying as the inverse power of the distance. Varying the power in this long-range model corresponds, in a one-to-one relationship, to change the dimension in spin-glass short-range models. Evidence for a spin-glass transition in magnetic field is found also for systems whose equivalent dimension is below the upper critical dimension at zero magnetic field.
Melting transition of an Ising glass driven by magnetic field  [PDF]
L. Arrachea,D. Dalidovich,V. Dobrosavljevi?,M. J. Rozenberg
Physics , 2003, DOI: 10.1103/PhysRevB.69.064419
Abstract: The quantum critical behavior of the Ising glass in a magnetic field is investigated. We focus on the spin glass to paramagnet transition of the transverse degrees of freedom in the presence of finite longitudinal field. We use two complementary techniques, the Landau theory close to the T=0 transition and the exact diagonalization method for finite systems. This allows us to estimate the size of the critical region and characterize various crossover regimes. An unexpectedly small energy scale on the disordered side of the critical line is found, and its possible relevance to experiments on metallic glasses is briefly discussed.
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