Friday, 25 May 2018

Concentration analysis of breast tissue phantoms with terahertz spectroscopy

Image result for vince wallace terahertzTruong, Bao CQ, Anthony J. Fitzgerald, Shuting Fan, and Vincent P. Wallace. "Concentration analysis of breast tissue phantoms with terahertz spectroscopy." Biomedical optics express 9, no. 3 (2018): 1334-1349.


Terahertz imaging has been previously shown to be capable of distinguishing normal breast tissue from its cancerous form, indicating its applicability to breast conserving surgery. The heterogeneous composition of breast tissue is among the main challenges to progressing this potential research towards a practical application. In this paper, two concentration analysis methods are proposed for analyzing phantoms mimicking breast tissue. The dielectric properties and the double Debye parameters were used to determine the phantom composition. The first method is wholly based on the conventional effective medium theory while the second one combines this theoretical model with empirical polynomial models. Through assessing the accuracy of these methods, their potential for application to quantifying breast tissue pathology was confirmed.

The group used "All terahertz time-domain spectroscopy measurements were conducted in reflection mode using a TeraPulse4000 system (TeraView Ltd, Cambridge, UK). The system produces THz pulses with a spectral range from 0.06 to 4 THz."

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Tuesday, 22 May 2018

Low dielectric constant composites based on B2O3 and SiO2 rich glasses, cordierite and mullite

Szwagierczak, D., B. Synkiewicz, and J. Kulawik. "Low dielectric constant composites based on B 2 O 3 and SiO 2 rich glasses, cordierite and mullite." Ceramics International(2018).

The paper reports on sintering and dielectric properties of several glass-ceramic composites based on B2O3 and SiO2 rich glasses, cordierite and mullite. The dielectric constant values for the developed composites are low, in the range of 4.8–6.7 at 1 MHz. Some of the investigated materials exhibit low sintering temperature, suitable for LTCC (low temperature cofired ceramics) technology. A selected composite characterized by a low sintering temperature of 920 °C, low dielectric constant of 4.7 at 1 THz, thermal expansion coefficient well fitted to silicon and compatibility with commercial thick film conductive pastes was used for preparation of green tapes destined for LTCC microwave substrates.

Dielectric constant of this material was additionally determined in the range 0.15–3 THz using time domain spectroscopy (Teraview). 3. Results and discussion. Fig … 

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