ABSTRACT
The effect of applying a negative bias during deposition of a previously designed multilayer solar selective absorber coating was studied on two types of substrates (316L stainless steel and Inconel 625). The solar selective coating is composed of different chromium aluminum nitride layers deposited using a combination of radiofrequency (RF), direct current (DC), and high-power impulse magnetron sputtering (HiPIMS) technologies. The chemical composition is varied to generate an infrared reflective/absorber layer (with low Al addition and N vacancies) and two CrAlN intermediate layers with medium and high aluminum content (Al/Cr = 0.6 and 1.2). A top aluminum oxide layer (Al2O3) is deposited as an antireflective layer. In this work, a simultaneous DC-pulsed bias (-100 V, 250 kHz) was applied to the substrates in order to increase the film density. The optical performance, thermal stability, and oxidation resistance was evaluated and compared with the performance obtained with similar unbiased coating and a commercial Pyromark paint reference at 600, 700, and 800 °C. The coating remained stable after 200 h of annealing at 600 °C, with solar absorptance (α) values of 93% and 92% for samples deposited on stainless steel and Inconel, respectively, and a thermal emittance ε25°C of 18%. The introduction of additional ion bombardment during film growth through bias assistance resulted in increased durability, thermal stability, and working temperature limits compared with unbiased coatings. The solar-to-mechanical energy conversion efficiency at 800 °C was found to be up to 2 times higher than Pyromark at C = 100 and comparable at C = 1000.
ABSTRACT
We present a detailed study about the substrate-induced strain and thickness effects on the structure and magnetic properties of La0.5Sr0.5CoO3 films. The in-plane tensile or compressive strain imposed by four different substrates configures an in-plane or out-of-plane easy axis, respectively. The presence of a soft magnetic phase at the interface is also conditioned by the type of strain. The obtained results are discussed in terms of the different anisotropies that participate and control the final magnetic behavior. The relevance of these results lies in the feasibility of La0.5Sr0.5CoO3 in memory applications and spintronic devices.
ABSTRACT
BACKGROUND: The Cancer of the Prostate Risk Assessment Postsurgical (CAPRA-S) score is a tool to stratify patients into groups according to their risk for biochemical recurrence after radical prostatectomy. The aim of this study was to assess the accuracy of the CAPRA-S score for predicting biochemical progression at 5 and 10 years in our cohort of patients after radical prostatectomy. PATIENTS AND METHODS: Between June 2004 and December 2015, radical prostatectomy was performed as the main treatment option for patients with localized prostate cancer. Patients who had received adjuvant or neoadjuvant treatment were excluded from this study. Biochemical progression after radical prostatectomy was considered in patients by prostate-specific antigen (PSA) > 0.1 ng/mL after surgery (biochemical persistence) and by at least 2 determinations of PSA > 0.2 ng/mL in those patients with initial undetectable postoperative PSA any time during their follow-up (biochemical failure). Cox proportional hazard model and Kaplan-Meier analysis were used for the statistical analysis. RESULTS: Of 531 patients who underwent radical prostatectomy, 479 met the inclusion criteria. Mean follow-up was 85 months (min-max, 13-153 months). The rate of biochemical progression-free survival at 10 years was 84.2%, 55.1%, and 32.8%, respectively, for high-, intermediate-, and low-risk patients according to the CAPRA-S score. The concordance index for CAPRA-S predicting biochemical progression at 5 years was 0.71 and at 10 years was 0.70. CONCLUSION: The CAPRA-S score is a useful and easy-to-use tool in patients after radical prostatectomy to classify their risk for biochemical progression, thus helping decide if adjuvant treatment should be required.
