Correlation between dielectric loss, microstructures and phase structures in a novel Mg n+1 Ti n O 3n+1 microwave ceramic system

2017 ◽  
Vol 198 ◽  
pp. 35-41 ◽  
Author(s):  
Fei Liu ◽  
Jingjing Qu ◽  
Changlai Yuan ◽  
Xianpei Huang ◽  
Guohua Chen ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
Ceramic System ◽  
Phase Structures ◽  
Microwave Ceramic

Microwave Sintering of Large Products

1996 ◽  
Vol 430 ◽  
Author(s):  
Tasaburo Saji
Keyword(s):  
Dielectric Loss ◽  
Wave Energy ◽  
Microwave Sintering ◽  
Processing System ◽  
Uniform Electric Field ◽  
Sintering Process ◽  
Gyrotron Oscillator ◽  
Microwave Ceramic ◽  
Fine Crystalline Structure ◽  
Ceramic Sintering

AbstractA practical microwave ceramic sintering technology has been developed. To achieve the highest merit from microwave sintering, susceptors were not used. In this paper, the ceramic sintering process using the 28GHz mm-wave energy generated by a Gyrotron oscillator is described. Large sized (Φ 200 × 200 ) and complex shaped material of Si3N4, A12O3, and ZrO2 were successfully and reproducibly sintered. The sintered bodies exhibited high density and fine crystalline structure. The processed materials were found to have exceptional strength and toughness.The critical processing technology developed dealt with the means by which uniform and defect free sintered bodies are obtained. The processing stressed the importance of achieving a uniform electric field within the applicator and to decrease the sintering dependence on the materials’ temperature based dielectric loss properties. With the use of innovative support and thermal insulation structures, the processing system allowed for very precise temperature controls.

Sn-doped BaO–TiO2–ZnO Microwave Ceramics

2002 ◽  
Vol 17 (6) ◽  
pp. 1550-1552 ◽  
Author(s):  
Wu Shunhua ◽  
Wang Guoqing ◽  
Zhao Yushuang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Temperature Coefficient ◽  
Sintering Temperature ◽  
Volume Resistivity ◽  
Ceramic Materials ◽  
Microwave Ceramics ◽  
Microwave Ceramic ◽  
Tan Δ

Sn-doped BaO–TiO2–ZnO (BTZ) microwave ceramic materials were investigated as a function of SnO2 content. Addition of a small amount of SnO2 (0.01–0.06 wt%) lowered the sintering temperature of the system to 1160 °C and also greatly reduced the dielectric loss (tan δ), which is closely related to the insulation resistivity. The Sn-doped BTZ materials were found to have excellent dielectric properties at 1 GHz with dielectric constant Ε ≈tangent tan δ ≤ 1 × 10−4, temperature coefficient of dielectric constant, αΕ = 0 ± 30 ppm/°C, and volume resistivity ρv ≥ 1013 ω cm.

Effects of Co2O3 on the Dielectric Properties of Mg2TiO4- Mg2SiO4 Microwave Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 13-14
Author(s):  
Ling Xia Li ◽  
Xiao Dong Sun ◽  
Xia Wan Wu
Keyword(s):  
Dielectric Properties ◽  
Dielectric Loss ◽  
Ceramic Material ◽  
Sintering Temperature ◽  
Q Value ◽  
Microwave Ceramics ◽  
High Q ◽  
Microwave Ceramic ◽  
Quality Factor Q ◽  
Low Permittivity

Effect of Co2O3 on microstructure and dielectric properties of Mg2TiO4-Mg2SiO4 microwave ceramic with low permittivity and high Q value was studied. Co2O3 acts and results in decreasing of the sintering temperature and densification of the ceramic material. As a result, the dielectric loss decreases and quality factor Q increases. Mg2+ is replaced partially with Co2+ in Mg2TiO4 to form (Mg,Co)2TiO4. It is demonstrated that the system with 2.4 wt% Co2O3 possesses better dielectric properties.

Study on phase structures and compositions, microstructures, and dielectric characteristics of (1-x)NdGaO3-xBi0.5Na0.5TiO3 microwave ceramic systems

2020 ◽  
Vol 46 (10) ◽  
pp. 16185-16195
Author(s):  
Fei Liu ◽  
Jing-Jing Qu ◽  
Hong-Ge Yan ◽  
Chang-Lai Yuan ◽  
Ting-Ting Wei ◽  
...  
Keyword(s):  
Dielectric Characteristics ◽  
Phase Structures ◽  
Microwave Ceramic

Some Applications of the U. S. Steel MVEM

1973 ◽  
Vol 31 ◽  
pp. 4-5
Author(s):  
J. S. Lally ◽  
L. E. Thomas ◽  
R. M. Fisher
Keyword(s):  
Electron Diffraction ◽  
Debye Temperature ◽  
Metals And Alloys ◽  
Critical Voltage ◽  
Dynamical Diffraction ◽  
Phase Structures ◽  
Structure Factors ◽  
Local Bonding ◽  
Diffraction Phenomenon ◽  
Multi Phase

A variety of materials containing many different microstructures have been examined with the USS MVEM. Three topics have been selected to illustrate some of the more recent studies of diffraction phenomena and defect, grain and multi-phase structures of metals and minerals.(1) Critical Voltage Effects in Metals and Alloys - This many-beam dynamical diffraction phenomenon, in which some Bragg resonances vanish at certain accelerating voltages, Vc, depends sensitively on the spacing of diffracting planes, Debye temperature θD and structure factors. Vc values can be measured to ± 0.5% in the HVEM ana used to obtain improved extinction distances and θD values appropriate to electron diffraction, as well as to probe local bonding effects and composition variations in alloys.

MECHANICAL AND DIELECTRIC LOSS SPECTRA OF AMBERS

1985 ◽  
Vol 46 (C10) ◽  
pp. C10-565-C10-568
Author(s):  
M. WELLER ◽  
C. A. WERT ◽  
D. SCHLEE
Keyword(s):  
Dielectric Loss

Solid-phase structures of cerebrospinal fluid in diagnosis of early asymptomatic neurosyphilis

2018 ◽  
pp. 56-61
Author(s):  
С.Н. Шатохина ◽  
Н.А. Кузнецова ◽  
В.Н. Шабалин
Keyword(s):  
Cerebrospinal Fluid ◽  
Visual Analysis ◽  
Solid Phase ◽  
Biological Fluids ◽  
Laboratory Methods ◽  
Phase Structures ◽  
Morphological Picture ◽  
Diagnostic Technology

Цель проведённого исследования состояла в оценке эффективности визуального анализа твёрдофазных структур спинномозговой жидкости для диагностики ранних форм нейросифилиса. Методы. Использован метод краевой дегидратации биологических жидкостей, входящий в состав авторской диагностической технологии «Литос-система». Диагностика раннего асимптомного нейросифилиса заключается в выявлении деструктивных образований в форме овалов в морфологической картине твёрдой фазы спинномозговой жидкости. Результаты. Проведён сравнительный анализ результатов исследования спинномозговой жидкости у 19 больных с подтверждённым диагнозом «ранний асимптомный нейросифилис», полученных традиционными лабораторными методами и методом краевой дегидратации. Выявлено, что локализация овалов внутри сферолитов указывает на длительность заболевания нейросифилисом менее трёх лет, а вне сферолитов - от трех до пяти лет. Заключение. Метод краевой дегидратации позволяет диагностировать ранний асимптомный нейросифилис по наличию деструктивных образований в форме овалов в морфологической картине твёрдой фазы спинномозговой жидкости. The aim of this study was to evaluate effectiveness of visual analysis of solid-phase structures in cerebrospinal fluid to diagnose early forms of neurosyphilis. Methods. We used a method of marginal dehydration of biological fluids as a part of the author’s diagnostic technology, Litos-System. Early asymptomatic neurosyphilis is diagnosed based on detection of destructive, oval-shaped formations in the morphological picture of cerebrospinal fluid solid phase. Results. Data from analyses of cerebrospinal fluid performed with traditional laboratory methods and the method of marginal dehydration were compared for 19 patients with documented diagnosis of early asymptomatic neurosyphilis. A localization of ovals within spherulites indicated a less than a three-year duration of neurosyphilis while a localization outside spherulites indicated a duration of three to five years. Conclusion. The method of marginal dehydration allows detecting early asymptomatic neurosyphilis based on the presence of destructive, oval-shaped formations in the morphological picture of cerebrospinal fluid solid phase.

Sparse Representation Based Dielectric Loss Angle Measurement

2015 ◽  
Vol 9 (1) ◽  
pp. 566-570
Author(s):  
Zhang Ji ◽  
Jianfeng Zheng
Keyword(s):  
Dielectric Loss ◽  
Power Systems ◽  
Sparse Representation ◽  
Precise Measurement ◽  
Angle Measurement ◽  
Measuring Error ◽  
Loss Angle ◽  
Analysis Method ◽  
Electric Capacity ◽  
Dielectric Loss Angle

Precise measurement of dielectric loss angle is very important for electric capacity equipment in recent power systems. When signal-to-noise is low and fundamental frequency is fluctuating, aiming at the measuring error of dielectric loss angle based on some recent Fourier transform and wavelet transform harmonics analysis method, we propose a novel algorithm based on sparse representation, and improved it to be more flexible for signal sampling. Comparison experiments describe the advantages of our method.

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