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This research investigates the reparative impact of photoelectrochemical (PEC) reactions on damage induced by inductively coupled plasma (ICP) etching in process of the Schottky barrier diodes (SBDs). After the PEC reaction repair, the reverse leakage current of the devices exhibited a significant reduction, typically ranging from 1 to 3 orders of magnitude. The ideality factor decreased from approximately 5 to 2, accompanied by a simultaneous decrease in series resistance. SBDs subjected to PEC processing displayed a notable decline in frequency dispersion. Quantitative analysis from capacitance-frequency measurements indicated that the PEC process effectively rectified the damage caused by dry etching on the GaN surface. The results of X-ray Photoelectron Spectroscopy (XPS) showed that the gallium oxide formed on a GaN surface by PEC treatment and the ratio of N/(Al + Ga) becomes larger, which indicates that fewer nitrogen vacancies (NV) after PEC repair process. The mechanism of the repair effects of PEC for the SBDs were discussed and analyzed. The observed improvements underscore the efficacy of PEC reactions in mitigating the adverse effects of etching, providing some inspirations for the enhancement of SBD performance in GaN-based devices. [ABSTRACT FROM AUTHOR]

Heusler-type ferromagnetic shape memory alloys possess attractive multifunctional properties, including magnetic field induced shape memory effect, magnetoresistance and magnetocaloric effect, owing to the unique concurrent magnetic and martensitic transformations. However, these intermetallics generally exhibit intrinsic high brittleness and low strength, which severely impede their workability for processing and applicability in real use. In this study, we demonstrate a new grain refining strategy by means of eutectic solidification to improve the mechanical properties in Ni–Mn–Sn–Fe alloys. In a fully eutectic microstructure, the average γ lamellae thickness was refined to ∼170 nm and the composite showed a compressive strength of 1950 MPa, ductility of 19.5%, Young's Modulus of 38 GPa, pseudoelasticity of 3.2% and high mechanical cyclic stability. The high mechanical performance is attributed to the effect of departmentalisation of the brittle Heusler alloy by the densely distributed γ phase fine lamellae in resisting crack propagation. The eutectic Heusler composite exhibited a metamagnetic phase transformation, with a magnetic entropy change of 10.2 J/kg·K and a refrigeration capacity of 181 J/kg in a field change of 5 T. Image, graphical abstract [ABSTRACT FROM AUTHOR]

The purpose of this study is to evaluate the treatment plan adequacy and delivery efficiency among volumetric-modulated arc therapy (VMAT) with one or two arcs and the conventional static-field dynamic multileaf collimator (dMLC) intensity-modulated radiation therapy (IMRT) in patients undergoing oropharyngeal carcinoma. Fifteen patient cases were included in this investigation. Each of the cases was planned using step-and-shoot IMRT, VMAT with a single arc (Arc1) and VMAT with double arcs (Arc2). A two-dose level prescription for planning target volumes (PTVs) was delivered with 70 Gy/56 Gy in 30 fractions. Comparisons were performed of the dose-volume histograms (DVH) for PTVs, the DVH for organs at risk (OARs), the monitor units per fraction (MU/fx), and delivery time. IMRT and Arc2 achieved similar target coverage, but superior to Arc1. Apart from the oral cavity, Arc1 showed no advantage in sparing of OARs compared with IMRT, while Arc2 obtained equivalent or better sparing of OARs among the three techniques. VMAT reduced MU/fx and shortened delivery time remarkably compared with IMRT. Our results demonstrated that for oropharyngeal cases, Arc2 can achieve superior target coverage and normal tissue sparing, as well as a significant reduction in treatment time. [ABSTRACT FROM AUTHOR]

Purpose: The purposes of this study were to quantify respiration-induced organ motions for pancreatic cancer patients and to explore strategies to account for these motions. Methods and Materials: Both 3-dimensional computed tomography (3DCT) and 4-dimensional computed tomography (4DCT) scans were acquired sequentially for 15 pancreatic cancer patients, including 10 randomly selected patients and 5 patients selected from a subgroup of patients with large tumor respiratory motions. 3DCTs were fused with 2 sets of 4DCT data at the end of exhale phase (50%) and the end of inhale phase (0%). The target was delineated on the 50% and 0% phase CT sets, and the organs at risk were drawn on the 3DCT. These contours were populated to the CT sets at other respiratory phases based on deformable image registration. Internal target volumes (ITV) were generated by tracing the target contours of all phases (ITV10), 3 phases of 0%, 20% and 50% (ITV3), and 2 phases of 0% and 50% (ITV2). ITVs generated from phase images were compared using percentage of volume overlap, Dice coefficient, geometric centers, and average surface distance. Results: Volume variations of pancreas, kidneys, and liver as a function of respiratory phases were small (<5%) during respiration. For the 10 randomly selected patients, peak-to-peak amplitudes of liver, left kidney, right kidney, and the target along the superior-inferior (SI) direction were 7.9 ± 3.2 mm, 7.1 ± 3.1 mm, 5.7 ± 3.2 mm, and 5.9 ± 2.8 mm, respectively. The percentage of volume overlap and Dice coefficient were 92% ± 1% and 96% ± 1% between ITV10 and ITV2 and 96% ± 1% and 98% ± 1% between ITV10 and ITV3, respectively. The percentage of volume overlap between ITV10 and ITV3 was 93.6 ± 1.1 for patients with tumor motion >8 mm. Conclusions: Appropriate motion management strategies are proposed for radiation treatment planning of pancreatic tumors based on magnitudes of tumor respiratory motions. [ABSTRACT FROM AUTHOR]

Abstract: Although wurtzite ZnO has a simple crystal structure, the mechanism of its photoluminescence is still controversial and this topic has attracted numerous research efforts. The polycrystalline ZnO thin films studied here were deposited on Si (100) substrate by sputtering in pure Ar atmosphere, and then thermally annealed in air at various temperatures ranging from 300°C to 1050°C. The photoluminescence spectra of the as-synthesized ZnO thin films exhibited some interesting results: two novel and remarkable blue-violet emission peaks around 415nm and 440nm were discovered, while the usual strong green emission peak at 450–550nm was absent. These two blue-violet peaks might originate from zinc interstitial and zinc vacancy point defects, which were introduced during sputtering in a non-oxygen atmosphere. Strong blue-violet emissions of ZnO are highly desirable and they have great potential in light emitting and biological fluorescence labeling applications. [Copyright &y& Elsevier]

Achieving concurrent good mechanical and magnetic properties is highly desirable for ferromagnetic shape memory alloys for meaningful applications, yet is challenging due to the difficulty to combine ideal microstructure and magnetism in one. This work demonstrates an alloy design strategy to overcome this challenge in a Ni 51.5 Mn 40-x Fe x Sn 8.5 (x = 5, 6, 7) alloy system via microstructure engineering and composition tuning for its eutectic dual-phase microstructure. The alloys achieved a high strength of ∼2000 MPa and a ductility of ∼21%. In the meantime, the martensitic transformation was controlled within a particular temperature window between the Curie transition temperatures of the austenite and the martensite. This gives rise to the largest possible difference in saturation magnetization across the transformation and thus the highest driving force for the magnetic field mediated functionalities. • Fe addition of 5–7 at% in Ni 51.5 Mn 40-x Sn 8.5 Fe x Heusler alloys all resulted in a Heusler-γ phase nanoeutectic microstructure. • Alloy Fe6 shows the highest strength of ∼2000 MPa and ductility of ∼21% with the finest eutectic lamellar morphology. • Alloy Fe6 complies with the T C M < M s < T C A condition and shows a transformation sequence of A(ferro) ⇄ M(para), with the concurrent best mechanical properties. [ABSTRACT FROM AUTHOR]

Abstract: In order to improve the stability and decrease the cytotoxicity of silver nanoparticle (AgNP), a polyethyleneimine-modified reduced graphene oxide (PEI-rGO) was used as the substrate of AgNPs, and a PEI-rGO–AgNP hybrid was prepared by anchoring the AgNPs on the reduced graphene oxide surface. Such a hybrid showed substantially higher antibacterial activity than polyvinyl pyrrolidone (PVP)-stabilized AgNP, and the AgNPs on PEI-rGO were more stable than the AgNPs on PVP, resulting in long-term antibacterial effects. The hybrid showed excellent water-solubility and lower cytotoxicity, suggesting the great potential application as a sprayable graphene-based antibacterial solution. [Copyright &y& Elsevier]