Fabrication of Al2O3 coated 2D TiO2 nanoparticle photonic crystal layers by reverse nano-imprint lithography and plasma enhanced atomic layer deposition.

This paper reports simple process to enhance the extraction efficiency of photoluminescence (PL) from Eu-doped yttrium oxide (Y2O3:Eu3+) thin-film phosphor (TFP). Two-dimensional (2D) photonic crystal layer (PCL) was fabricated on Y2O3:Eu3+ phosphor films by reverse nano-imprint method using TiO2 nanoparticle solution as a nano-imprint resin and a 2D hole-patterned PDMS stamp. Atomic scale controlled Al2O3 deposition was performed onto this 2D nanoparticle PCL for the optimization of the photonic crystal pattern size and stabilization of TiO2 nanoparticle column structure. As a result, the light extraction efficiency of the Y2O3:Eu3+ phosphor film was improved by 2.0 times compared to the conventional Y2O3:Eu3+ phosphor film.

Characteristics of CVD graphene nanoribbon formed by a ZnO nanowire hardmask.

A graphene nanoribbon (GNR) is an important basic structure to open a bandgap in graphene. The GNR processes reported in the literature are complex, time-consuming, and expensive; moreover, the device yield is relatively low. In this paper, a simple new process to fabricate a long and straight graphene nanoribbon with a high yield has been proposed. This process utilizes CVD graphene substrate and a ZnO nanowire as the hardmask for patterning. 8 µm long and 50-100 nm wide GNRs were successfully demonstrated in high density without any trimming, and ∼ 10% device yield was realized with a top-down patterning process. After passivating the surfaces of the GNRs using a low temperature atomic layer deposition (ALD) of Al(2)O(3), high performance GNR MOSFETs with symmetric drain-current-gate-voltage (I(d)-V(g)) curves were demonstrated and a field effect mobility up to ∼ 1200 cm(2) V(-1) s(-1) was achieved at V(d) = 10 mV.

The variation of the enhanced photoluminescence efficiency of Y2O3:Eu3+ films with the thickness to the photonic crystal layer.

This study examined the effects of the thickness of Y(2)O(3):Eu(3+) phosphor films on quartz substrates coated with two-dimensional (2D) SiO(2) square-lattice nanorod photonic crystal layers (PCL) at identical heights on their extraction and absorption efficiency. The photoluminescence (PL) efficiency enhancement ratio decreased exponentially with increasing Y(2)O(3):Eu(3+) film thickness. The 2D PCL-assisted Y(2)O(3):Eu(3+) film with a thickness (t) = 400 nm showed enhancement in the upward and downward PL emission by factors of 6.2 and 8.6, respectively, with respect to those of a conventional flat film. This observation was attributed to diffraction scattering of the excitation and emission light.

Midterm outcomes of open surgical repair compared with thoracic endovascular repair for isolated descending thoracic aortic disease.

OBJECTIVE: This study aimed to assess the surgical morbidity and mortality of thoracic endovascular repair (TEVAR) as compared with open surgical repair (OSR) for isolated descending thoracic aortic disease. MATERIALS AND METHODS: From January 1, 2006 through May 31, 2010, a total of 68 patients with isolated descending thoracic aortic disease were retrospectively reviewed for the presence of perioperative complication, 30-day mortality, and clinical success. The patients were divided into two groups (group 1, OSR, n = 40 vs. group 2, TEVAR, n = 28) and these groups were compared for major variables and late outcomes. RESULTS: The mean age was 58 years (group I = 54 vs. group II = 63 years, p = 0.011). Significant perioperative complications occurred in 12 patients: 8 (20%) in group I and 4 (13%) in group II (p = 0.3). There were five 30 day mortalities of which 4 occurred in group I and 1 in group II (p = 0.23). Clinical success (effective aortic remodeling and complete false lumen obliteration or thrombosis) was achieved in 20 patients (71%). Mean Kaplan-Meier survival rate at 1 year was similar for both groups (group 1 = 87% vs. group 2 = 80%, p = 0.65). CONCLUSION: Thoracic endovascular repair for isolated thoracic aortic disease shows comparable results to OSR. However, the potential for endoleak or rupture remains a challenge that needs to be addressed in the future. Therefore, close follow-up study is needed for the evaluation of satisfactory long-term outcomes.