Research on glass ceramics with negative coefficient of thermal expansion used as fiber Bragg grating substrate

2004 ◽  
Author(s):  
Lijun Kang ◽  
Tong Liu ◽  
Zhimei Su ◽  
Yu'e Kong
2013 ◽  
Vol 189 ◽  
pp. 195-203 ◽  
Author(s):  
Marco Esposito ◽  
Salvatore Buontempo ◽  
Angelo Petriccione ◽  
Mauro Zarrelli ◽  
Giovanni Breglio ◽  
...  

Author(s):  
Ruiqi Ma ◽  
Guoqing Feng ◽  
Huilong Ren ◽  
Peng Fu ◽  
Shuang Wu ◽  
...  

Hull monitoring system with Fiber Bragg Grating (FBG) sensors increasingly receives people’s attentions. However, for the ship hull monitoring, the deformation of hull girder changes a lot as is subjected to a huge temperature variation. Therefore, the compensation method with only FBG temperature self-correction is not suitable for the hull monitoring sensors because no material thermal expansion effects are reasonably included. In this paper, the new compensation method of hull monitoring FBG sensor based on the sensor theory with both FBG temperature self-correction and steel thermal expansion effects correction is studied. The coupled compensation method suitable for hull monitoring sensor is obtained by theoretical derivation. As the comparison, the coupled compensation experiment was carried out. The results show that the relative error under the temperature compensation method is large in the case of drastic strain and temperature changes, and the correction results of the tested method will be closer to the true level.


2016 ◽  
Vol 45 (11) ◽  
pp. 4888-4895 ◽  
Author(s):  
Christian Thieme ◽  
Christian Rüssel

The compound BaZn2Si2O7 shows a highly positive coefficient of thermal expansion, while replacement of more than 10% of Ba2+ by Sr2+ results in a negative coefficient of thermal expansion.


2010 ◽  
Vol 160-162 ◽  
pp. 1270-1275
Author(s):  
Sheng Ching Wang ◽  
Hsi Hsun Tsai

A stabilized laser is essential for optical fiber communication network. One of the passive technique for stabilization of central wavelength of laser is based on the application of fiber Bragg gratings. Due to the positive coefficient of thermal expansion of optical fiber, the Bragg gratings within the fiber written by excimer laser gives about 0.01nm/oC shift on the central wavelength respect to the ambient temperature which leads serious problem in the communication network. Since both the temperature and tension force are linearly proportional to the central wavelength of fiber Bragg gratings. A feasible approach to derive the wavelength stabilization is to decrease the tension force of fiber Bragg gratings respect to the increase of ambient temperature. In this paper, a Kovar substrate with negative coefficient of thermal expansion is used to decrease the tension force while the environmental temperature increases. The experimental results show that the coefficient of thermal expansion of the Kovar substrate is negative and linearly proportional to the temperature. Thus, this Kovar substrate differing from the constant negative coefficient of thermal expansion ceramic substrate induces about 0.0085nm/C on the fiber Bragg gratings, which shows the well application of this Kovar for athermalization of the fiber Bragg gratings in optical communication system.


2015 ◽  
Vol 9 (2) ◽  
pp. 117-123 ◽  
Author(s):  
Gamal Khater ◽  
Safiah Abu ◽  
Esmat Hamzawy

Dark brown glasses were prepared from residues of basalt quarries and wastes of ceramic factories. Addition of CaF2, Cr2O3 and their mixture CaF2-Cr2O3 were used as nucleation catalysts. Generally, structures with augite and anorthite as major phases and small amount of magnetite and olivine phases were developed through the crystallization process. In the samples heat treated at 900?C the dominant phase is augite, whereas the content of anorthite usually overcomes the augite at higher temperature (1100?C). Fine to medium homogenous microstructures were detected in the prepared glass-ceramic samples. The coefficient of thermal expansion and microhardnessmeasurements of the glass-ceramic samples were from 6.16?10-6 to 8.96?10-6?C-1 (in the 20-500?C) and 5.58 to 7.16GP, respectively.


Author(s):  
Chunyan Wang ◽  
Dahu Chang ◽  
Junfei Wang ◽  
Qilong Gao ◽  
Yinuo Zhang ◽  
...  

New membrane vibration and surface symmetry breaking effects determine the negative coefficient of thermal expansion at the nanoscale.


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