RESUMEN
Optical grade silicone has various properties that make it attractive for solar concentrators, such as excellent transmission across the solar spectrum and flexible moldability for freeform profiles. In this study, a glass-silicone lens structure is proposed to reduce the optothermal effect on the silicone lens. Experimental measurements and simulation modeling results demonstrate that the focal length sensitivity of the glass-silicone lens with respect to temperature can be reduced by a factor of 10 when compared to a silicone lens alone. This model has been extended to the simulation of a proposed two-stage silicone solar concentrator, consisting of an array of acylindrical lenslets and rows of waveguides that focus light onto microphotovoltaic cells. The optical efficiency of the solar concentration system showed a change of less than 10% compared to the efficiency at room temperature for temperature changes from -10∘C to 70°C.
RESUMEN
The use of silicone optical elements is demonstrated for a concentrated photovoltaic system. These components show over 96% transmission through most of the solar spectrum and excellent temperature stability. Unique moldability enables the use of complex freeform designs. A light, compact, and cost-effective concentrated photovoltaic system based on silicone optics is proposed. In this system, air-plasma treatment is utilized to overcome the mechanical properties of silicone and difficulties with coating to reduce Fresnel loss. Lens arrays and waveguides are fabricated by injection molding following freeform optical design by LightTools. First-order characterizations are also performed.
RESUMEN
OBJECTIVE: To investigate the association between high-sensitivity C-reactive protein and peripheral arterial disease. METHODS: The study population comprised 643 subjects aged at least 40 years in whom both CRP and ankle-brachial index were measured. The survey included information on demographic characteristics, clinical examinations and ankle-brachial index (ABI). Ankle-brachial index (ABI) < 0.9 was diagnostic of PAD. RESULTS: 64 subjects (10%) were diagnosed as PAD. The prevalence of current smoking, hypertension, diabetes, low HDL cholesterol and history of cardiovascular disease in the participants with PAD were higher than without (P < 0.05). The prevalence of hypertension, diabetes, and history of cardiovascular disease was higher in subjects with high CRP (P < 0.05). In logistic regression analyses, the moderate CRP group and high CRP group had a two-fold higher OR compared with the low CRP group. The P-trend across CRP groups was statistically significant (P = 0.036). High log-transformed hs-CRP level was significantly related to PAD after adjustment for the cardiovascular risk factors mentioned above (P = 0.007). CONCLUSION: hs-CRP is related to PAD and high level hs-CRP is an independent risk factor for PAD in Chinese adults aged 40 years and more.