Highly oriented poly crystalline graphite (HOPG), boron-doped diamond (BDD), nanocrystalline diamond (NCD), ultra-nano-crystalline diamond (uNCD), fullerenes C60 and C70 and Diamond Like Carbon (DLC) surfaces are exposed to low pressure hydrogen plasma in a 13.56 MHz plasma reactor. Relative yields of surface produced Hions due to bombardment of positive ions from the plasma are measured by an energy analyzer cum quadrupole mass spectrometer. Irrespective of plasma conditions (0.2 and 2 Pa), HOPG surfaces show the highest yield at room temperature (RT), while at high temperature (HT), the highest yield (~ 5 times compared to HOPG surface at room temperature) is observed on BDD surfaces. The shapes of ion distribution functions (IDFs) are compared at RT and HT to demonstrate the mechanism of ion generation at the surface. Raman spectroscopy analyses of the plasma exposed samples reveal surface modifications influencing Hproduction yields, while further analyses strongly suggest that the hydrogen content of the material and the sp3/sp2 ratio are the key parameters in driving surface ionization efficiency of carbon materials under the chosen plasma conditions.
With the recent advances in the field of nanotechnology, measurement and manipulation requirements at the nanoscale have become more stringent than ever before. In atomic force microscopy, high-speed performance alone is not sufficient without considerations of other aspects of the measurement task, such as the feature aspect ratio, required range, or acceptable probe-sample interaction forces. In this paper, the authors discuss these requirements and the research directions that provide the highest potential in meeting them. The authors elaborate on the efforts toward the downsizing of self-sensed and self-actuated probes as well as on upscaling by active cantilever arrays. The authors present the fabrication process of active probes along with the tip customizations carried out targeting specific application fields. As promising application in scope of nanofabrication, field emission scanning probe lithography is introduced. The authors further discuss their control and design approach. Here, microactuators, e.g., multilayer microcantilevers, and macroactuators, e.g., flexure scanners, are combined in order to simultaneously meet both the range and speed requirements of a new generation of scanning probe microscopes.
Physiotherapy has recently become an essential part of enhanced recovery protocols after thoracic surgery. The evidence-based practice of physiotherapy is essential for the effective management of postoperative patients. Unfortunately, only a small body of literature has discussed the rationale of the physiotherapy interventions that are routinely implemented following thoracic surgery. Nonetheless, we can integrate the available knowledge into our practice until new evidence emerges. Therefore, in this review, the principles of physiotherapy after thoracic surgery are presented, along with a detailed description of physiotherapy interventions, with the goals of enhancing the knowledge and practical skills of physiotherapists in postoperative care units and helping them to re-evaluate and justify their traditional practices.
Single-electron devices operating at room temperature require sub-5 nm quantum dots having tunnel junctions of comparable dimensions. Further development in nanoelectronics depends on the capability to generate mesoscopic structures and interfacing these with complementary metal–oxide–semiconductor devices in a single system. The authors employ a combination of two novel methods of fabricating room temperature silicon single-electron transistors (SETs), Fowler–Nordheim scanning probe lithography (F-N SPL) with active cantilevers and cryogenic reactive ion etching followed by pattern-dependent oxidation. The F-N SPL employs a low energy electron exposure of 5–10 nm thick high-resolution molecular resist (Calixarene) resulting in single nanodigit lithographic performance [Rangelow et al., Proc. SPIE 7637, 76370V (2010)]. The followed step of pattern transfer into silicon becomes very challenging because of the extremely low resist thickness, which limits the etching depth. The authors developed a computer simulation code to simulate the reactive ion etching at cryogenic temperatures (−120 °C). In this article, the authors present the alliance of all these technologies used for the manufacturing of SETs capable to operate at room temperatures.
We report the synthesis of hybrid thin films based on Poly(MethylMethAcrylate) (PMMA) and Poly(VinylAlcohol) (PVA), doped with different concentrations of titanium dioxide nanoparticles (TiO2 NPs). As-prepared thin films of (PMMA-PVA) doped by TiO2 NPs (wt.% = 2%, 4%, 8%, and 16%) are deposited on glass substrate. Transmittance (T%), reflectance (R%), absorption coefficient (α), optical constants (n and k), and optical dielectric functions (ε1 and ε2) are deduced using the experimental transmittance and reflectance spectra. Furthermore, a combination of classical models such as Tauc, Urbach, Spitzer-Fan, and Drude models are applied to calculate the optical and optoelectronic parameters and the energy gaps of the prepared nanocomposite thin films. The optical bandgap energy of PMMA-PVA thin film is found to be 4.101 eV. Incorporation of TiO2 NPs into PMMA-PVA polymeric thin films leads to a decrease in the optical bandgap and thus bandgap engineering is possible. Fourier-transform infrared spectroscopy (FTIR) transmittance spectra of thin films are measured and interpreted to identify the vibrational modes. To elucidate the chemical stability, thermogravimetric (TGA) curves are measured. We found that (PMMA-PVA)/TiO2 NPs polymeric thin films are thermally stable below 110 °C enable them to be attractive for a wide range of optical and optoelectronic applications.
Articles you may be interested inMechanical properties of polymeric nanostructures fabricated through directed self-assembly of symmetric diblock and triblock copolymers J. Vac. Sci. Technol. B 30, 06F204 (2012); 10.1116/1.4766916 Development, analysis and control of a high-speed laser-free atomic force microscope Rev. Sci. Instrum. 81, 023707 (2010);Scanning probes have enabled modern nanoscience and are still the backbone of today's nanotechnology. Within the technological development of AFM systems, the cantilever evolved from a simple passive deflection element to a complex microelectromechanical system through integration of functional groups, such as piezoresistive detection sensors and bimaterial based actuators. Herein, the authors show actual trends and developments of miniaturization efforts of both types of cantilevers, passive and active. The results go toward the reduction of dimensions. For example, the authors have fabricated passive cantilever with a width of 4 lm, a length of 6 lm and thickness of 50-100 nm, showing one order of magnitude lower noise levels. By using active cantilevers, direct patterning on calixarene is demonstrated employing a direct, development-less phenomena triggered by tip emitted low energy (<50 eV) electrons. The scanning probes are not only applied for lithography, but also for imaging and probing of the surface before and immediately after scanning probe patterning. In summary, piezoresistive probes are comparable to passive probes using optical read-out. They are able to routinely obtain atomic step resolution at a low thermal noise floor. The active cantilever technology offers a compact, integrated system suited for integration into a table-top scanning probe nanolithography tool.
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