Diffusion Length Measurements of Minority Carriers in Si-SiO2 Using the Photo-Grating Technique

2000 ◽  
Vol 638 ◽  
Author(s):  
Y. Posada ◽  
I. Balberg ◽  
L.F. Fonseca ◽  
O. Resto ◽  
S.Z. Weisz

AbstractWe have studied the microstructure, the transport and the phototransport properties of the Si crystallites network in Si-SiO2 composites. We have found that in our co-sputtered samples the average crystallite diameter, d, decreases from 40 to 5 nm as the content of the silicon, x, decreases from 80 to 40 volume%, and that the percolation of the network sets is at x ≈ 40 vol%. A simultaneous study of the photoluminescence (PL) shows the, quantum confinement, expected red shift of its peak with increasing d. On the other hand the very strong observed decrease of the PL intensity with x is interpreted here as due to a deconfinement effect that is dominated by the increase in the cluster size of connected Si crystallites. The results suggest that a closed random packing of the Si crystallites will be the preferred network for high intensity electroluminescence.

2018 ◽  
Vol 30 (24) ◽  
pp. 2163-2166 ◽  
Author(s):  
Vadivukkarasi Jeyaselvan ◽  
Shankar Kumar Selvaraja

2021 ◽  
Vol 10 (21) ◽  
pp. 4891
Author(s):  
Piotr Tkocz ◽  
Tomasz Matusz ◽  
Łukasz Kosowski ◽  
Karolina Walewicz ◽  
Łukasz Argier ◽  
...  

Calcaneal spur and plantar fasciitis are the most common causes of plantar heel pain. There are many effective physical modalities for treating this musculoskeletal disorder. So far, the are no clear recommendations confirming the clinical utility of high-intensity laser therapy (HILT) in the management of painful calcaneal spur with plantar fasciitis. This study aimed to evaluate the effectiveness of HILT in pain management in patients with calcaneal spur and plantar fasciitis. A group of 65 patients was assessed for eligibility based on the CONSORT guidelines. This study was prospectively registered in the Australian New Zealand Clinical Trial Registry platform (registration number ACTRN12618000744257, 3 May 2018). The main eligibility criteria were: cancer, pregnancy, electronic and metal implants, acute infections, impaired blood coagulation, cardiac arrhythmias, taking analgesic or anti-inflammatory medications, non-experience of heel pain, or presence of other painful foot conditions. Finally, 60 patients were randomly assigned into two groups: study group (n = 30, mean age 59.9 ± 10.1), treated with HILT (7 W, 149.9 J/cm2, 1064 nm, 4496 J, 12 min), and placebo-controlled group (n = 30, mean age 60.4 ± 11.9), treated with sham HILT therapy. Both groups received ultrasound treatments (0.8 W/cm2, 1 MHz frequency, 100% load factor, 5 min). Treatment procedures were performed once a day, five times per week for three weeks (total of 15 treatment sessions). Study outcomes focused on pain intensity and were assessed before (M1) and after (M2) the treatment as well as after 4 (M3) and 12 (M4) weeks using the Visual Analogue Scale (VAS) and the Laitinen Pain Scale (LPS). According to VAS, a statistically significant decrease in the study group was observed between M1 and M2 by 3.5 pts, M1 and M3 by 3.7 pts, and M1 and M4 by 3.2 pts (p < 0.001). On the other hand, the control group showed a statistically significant decrease (p < 0.001) between M1 and M2 by 3.0 pts, M1 and M3 by 3.4 pts, and M1 and M4 by 3.2 pts. According to LPS, a statistically significant decrease in the study group was observed between M1 and M2 by 3.9 pts, M1 and M3 by 4.2 pts, and M1 and M4 by 4.0 pts (p < 0.001). On the other hand, the control group showed a statistically significant decrease between M1 and M2 by 3.2 pts (p = 0.002), M1 and M3 by 4.0 pts (p < 0.001), and M1 and M4 by 3.9 pts (p < 0.001). However, there were no statistically significant differences between the groups in VAS and LPS (p > 0.05). In conclusion, the HILT does not appear to be more effective in pain management of patients with calcaneal spurs and plantar fasciitis than the conservative standard physiotherapeutic procedures.


1971 ◽  
Vol 4 (1) ◽  
pp. 249-255 ◽  
Author(s):  
S. Rakshit ◽  
S. N. Biswas ◽  
A. N. Chakravarti

1997 ◽  
Vol 71 (15) ◽  
pp. 2121-2123 ◽  
Author(s):  
A. A. Istratov ◽  
C. Flink ◽  
H. Hieslmair ◽  
T. Heiser ◽  
E. R. Weber

The diffusion length of thermal neutrons in water has been measured at various temperatures between 18 and 255 °C, the source being 124 Sb-Be (25 keV). Diffusion length measurements were also made in water with three boric acid concentrations and with water poisoned with a cadmium sulphate solution, the measurements being taken over a temperature range of 18 to 200 °C. The variation with temperature of the diffusion coefficient of water was determined from the experiments with poisoned water. A value 0.324 + 0.006 barn was obtained for the 2200 m/s microscopic absorption cross section of hydrogen. Close agreement was found between the experimental results and theoretical predictions based on the Nelkin model for slow neutron scattering.


Sign in / Sign up

Export Citation Format

Share Document