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Evaluation of zirconia–porcelain interface using X-ray diffraction

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International Journal of Oral Science 2015年第3期7卷 187-195页

作者： Tariq F Alghazzawi Gregg M Janowski Department of Materials Science and Engineering School of Engineering The University of Alabama at Birmingham Department of Prosthetic Dental Sciences College of Dentistry Taibah University

The aim of this study was to determine if accelerated aging of porcelain veneering had an effect on the surface properties specific to a tetragonal-to-monoclinic transformation（TMT） of zirconia restorations. Thirty-six zirconia samples were milled and sintered to simulate core fabrication followed by exposure to various combinations of surface treatments including as-received（control）,hydrofluoric acid（HF）, application of liner plus firings, application of porcelain by manual layering and pressing with firing, plus accelerated aging. The quantity of transformed tetragonal to monoclinic phases was analyzed utilized an X-ray diffractometer and one-way analysis of variance was used to analyze data. The control samples as provided from the dental laboratory after milling and sintering process had no TMT（X m5 0）. There was an effect on zirconia samples of HF application with TMT（X m5 0.8%） and liner plus HF application with TMT（X m5 8.7%）. There was an effect of aging on zirconia samples（no veneering） with significant TMT（X m5 70.25%）. Both manual and pressing techniques of porcelain applications reduced the TMT（manual, X m5 4.41%, pressing,X m5 11.57%）, although there was no statistical difference between them. It can be concluded that simulated applications of porcelain demonstrated the ability to protect zirconia from TMT after aging with no effect of a liner between different porcelain applications.The HF treatment also caused TMT.

关键词： aging hydrofluoric acid monoclinic pressing tetragonal X-ray diffraction

Refractive index sensor based on tapered PCF in-line interferometer

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Chinese Optics Letters 2012年第9期10卷 13-16页

作者：刘奇王琴 Department of Materials Science and Engineering Nanjing University Nanjing University High-Tech Institute at Suzhou

A simple and compact refractive index sensor is demonstrated by tapering a photonic crystal fiber （PCF） in-line interferometer. The PCF is spliced between two single-mode fibers and tapered via hydrofluoric acid etching. Its sensitivity in liquid is more than an order of magnitude larger than the untapered one. By optimizing the etching process, we can fabricate more uniformly and thinly tapered PCF interferometers with higher sensitivity in the future.

关键词： Etching hydrofluoric acid Interferometers Photonic crystal fibers Refractometers Single mode fibers

Fabrication of grating structures on silicon carbide by femtosecond laser irradiation and wet etching

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Chinese Optics Letters 2016年第2期14卷 59-62页

作者：高博陈涛 Vanthanh Khuat 司金海侯洵 Key Laboratory for Physical Electronics and Devices of the Ministry of Education Shaanxi Key Lab of Information Photonic TechniqueSchool of Electronics & Information EngineeringXi’an Jiaotong University

A method for fabricating deep grating structures on a silicon carbide （SIC） surface by a femtosecond laser and chemical-selective etching is developed. Periodic lines corresponding to laser-induced structure change （LISC） are formed by femtosecond laser irradiation, and then the SiC material in the LISC zone is removed by a mixed solution of hydrofluoric acid and nitric acid to form grating grooves. Grating grooves with a high-aspect ratio of approximately 25 are obtained. To obtain a small grating period, femtosecond laser exposure through a phase mask was used to fabricate grating structures with a 1.07 μm period on the surface of the SiC.

关键词： Aspect ratio Diffraction gratings hydrofluoric acid Irradiation Ultrashort pulses

Bragg grating chemical sensor with hydrogel as sensitive element

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Chinese Optics Letters 2004年第12期2卷 683-685页

作者：刘小梅郑史烈章献民丛军陈抗生徐坚 Department of Information and Electronic Engineering Institute of Chemistry

A novel fiber Bragg grating (FBG) based chemical sensor using hydrogel, a swellable polymer, as sensitive element is demonstrated. The sensing mechanism relies on the shift of Bragg wavelength due to the stress resulted from volume change of sensitive swellable hydrogel responding to the change of external environment. A polyacrylamide hydrogel fiber grating chemical sensor is made, and the experiments on its sensitivity to the salinity are performed. The sensitivity is low due to the less stress from the shrinking or swelling of hdrogels. Reducing the cross diameter of the grating through etching with hydrofluoric acid can greatly improve the sensitivity of the sensor.

关键词： Fiber Bragg gratings hydrofluoric acid Hydrogels Salinity measurement