Artykuły w czasopismach na temat „Nanostructures”
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Gerbreders, V., M. Krasovska, I. Mihailova, E. Sledevskis, A. Ogurcovs, E. Tamanis, V. Auksmuksts, A. Bulanovs i V. Mizers. "Morphology Influence on Wettability and Wetting Dynamics of ZnO Nanostructure Arrays". Latvian Journal of Physics and Technical Sciences 59, nr 1 (1.02.2022): 30–43. http://dx.doi.org/10.2478/lpts-2022-0004.
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Abstract Changes in nanostructure morphology and size may result in very different surface wettability. In this research, the impact of different morphological parameters on the wetting dynamics of ZnO nanostructured layers is studied. Six different morphologies are chosen to determine the specific wetting processes of ZnO nanostructures: nanoneedles, small diameter rods, large diameter rods, nanotubes, nanoplates, and plain thin films. Wetting dynamics is investigated using conventional sessile drop technique and a novel approach based on electrochemical impedance spectroscopy. The results show that the surface of nanostructured ZnO thin films exhibits both hydrophilic and hydrophobic wetting behaviour, depending on nanostructure form, size, and orientation. ZnO nanostructure arrays are a promising platform for electrochemical and optical sensing in aqueous solutions. The full and effective use of the sensor working surface can be ensured only under the condition of complete wetting of the nanostructured layer. Therefore, it is important to take into account the peculiarities of the wetting process of a specific morphology of nanostructures.
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Hamza, Mohammed Salab, Suaad Salim Shaker i Khitam Salim Shaker. "Preparation and Study of morphological properties of ZnO nano Powder". Journal of Engineering 22, nr 4 (1.04.2016): 116–26. http://dx.doi.org/10.31026/j.eng.2016.04.08.
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In this work, ZnO nanostructures for powder ZnO were synthesized by Hydrothermal Method. Size and shape of ZnO nanostructureas can be controlled by change ammonia concentration. In the preparation of ZnO nanostructure, zinc nitrate hexahydrate [Zn(NO3)2·6H2O] was used as a precursor. The structure and morphology of ZnO nanostructure have been characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD). The synthesized ZnO nanostructures have a hexagonal wurtzite structure. Also using Zeta potential and Particle Size Analyzers and size distribution of the ZnO powder
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Yang, Ming, Xiaohua Chen, Zidong Wang, Yuzhi Zhu, Shiwei Pan, Kaixuan Chen, Yanlin Wang i Jiaqi Zheng. "Zero→Two-Dimensional Metal Nanostructures: An Overview on Methods of Preparation, Characterization, Properties, and Applications". Nanomaterials 11, nr 8 (23.07.2021): 1895. http://dx.doi.org/10.3390/nano11081895.
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Metal nanostructured materials, with many excellent and unique physical and mechanical properties compared to macroscopic bulk materials, have been widely used in the fields of electronics, bioimaging, sensing, photonics, biomimetic biology, information, and energy storage. It is worthy of noting that most of these applications require the use of nanostructured metals with specific controlled properties, which are significantly dependent on a series of physical parameters of its characteristic size, geometry, composition, and structure. Therefore, research on low-cost preparation of metal nanostructures and controlling of their characteristic sizes and geometric shapes are the keys to their development in different application fields. The preparation methods, physical and chemical properties, and application progress of metallic nanostructures are reviewed, and the methods for characterizing metal nanostructures are summarized. Finally, the future development of metallic nanostructure materials is explored.
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Zhang, Shiying, Huizhao Zhuang, Chengshan Xue i Baoli Li. "Effect of Annealing on Morphology and Photoluminescence of β-Ga2O3 Nanostructures". Journal of Nanoscience and Nanotechnology 8, nr 7 (1.07.2008): 3454–57. http://dx.doi.org/10.1166/jnn.2008.138.
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A novel method was applied to prepare one-dimensional β-Ga2O3 nanostructure films. In this method, β-Ga2O3 nanostructures have been successfully synthesized on Si(111) substrates through annealing sputtered Ga2O3/Mo films for differernt time under flowing ammonia. The as-synthesized β-Ga2O3 nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectrum. The results show that the formed nanostructures are single-crystalline Ga2O3 with monoclinic structure. The annealing time of the samples has an evident influence on the morphology and optical property of the nanostructured β-Ga2O3 synthesized. The representative photoluminescence spectrum at room temperature exhibits a strong and broad emission band centered at 411.5 nm and a relatively weak emission peak located at 437.6 nm. The growth mechanism of the β-Ga2O3 nanostructured materials is also discussed briefly.
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Wang, Ying, i Guo Zhong Cao. "Synthesis and Electrochemical Properties of V2O5 Nanostructures". Key Engineering Materials 336-338 (kwiecień 2007): 2134–37. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.2134.
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In this seminar, I will present our recent work on the growth and electrochemical properties of single crystalline vanadium pentoxide (V2O5) nanorod and Ni-V2O5·nH2O nanocable arrays. These nanostructures were prepared by solution synthesis and template-based electrodeposition. Processing, morphology, structure and electrochemical properties of these nanostructures will be discussed. These nanostructured electrodes of vanadium pentoxide demonstrate significantly enhanced intercalation capcity and charge/discharge rate compared to the plain film electrodes, due to the high surface area and short diffusion distance offered by nanostructure.
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Maciulis, Vincentas, Almira Ramanaviciene i Ieva Plikusiene. "Recent Advances in Synthesis and Application of Metal Oxide Nanostructures in Chemical Sensors and Biosensors". Nanomaterials 12, nr 24 (10.12.2022): 4413. http://dx.doi.org/10.3390/nano12244413.
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Nanostructured materials formed from metal oxides offer a number of advantages, such as large surface area, improved mechanical and other physical properties, as well as adjustable electronic properties that are important in the development and application of chemical sensors and biosensor design. Nanostructures are classified using the dimensions of the nanostructure itself and their components. In this review, various types of nanostructures classified as 0D, 1D, 2D, and 3D that were successfully applied in chemical sensors and biosensors, and formed from metal oxides using different synthesis methods, are discussed. In particular, significant attention is paid to detailed analysis and future prospects of the synthesis methods of metal oxide nanostructures and their integration in chemical sensors and biosensor design.
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Nocua, José E., Fabrice Piazza, Brad R. Weiner i Gerardo Morell. "High-Yield Synthesis of Stoichiometric Boron Nitride Nanostructures". Journal of Nanomaterials 2009 (2009): 1–6. http://dx.doi.org/10.1155/2009/429360.
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Boron nitride (BN) nanostructures are structural analogues of carbon nanostructures but have completely different bonding character and structural defects. They are chemically inert, electrically insulating, and potentially important in mechanical applications that include the strengthening of light structural materials. These applications require the reliable production of bulk amounts of pure BN nanostructures in order to be able to reinforce large quantities of structural materials, hence the need for the development of high-yield synthesis methods of pure BN nanostructures. Using borazine (B3N3H6) as chemical precursor and the hot-filament chemical vapor deposition (HFCVD) technique, pure BN nanostructures with cross-sectional sizes ranging between 20 and 50 nm were obtained, including nanoparticles and nanofibers. Their crystalline structure was characterized by (XRD), their morphology and nanostructure was examined by (SEM) and (TEM), while their chemical composition was studied by (EDS), (FTIR), (EELS), and (XPS). Taken altogether, the results indicate that all the material obtained is stoichiometric nanostructured BN with hexagonal and rhombohedral crystalline structure.
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Moon, Seung Kyun, Jae Sung Kwon, Seong Wan Baik, Gye Rok Jeon, Jung Hoon Ro, Tae Gwan Eom i Kyoung Nam Kim. "Surface Characteristics of Nanostructure Formed on Sand Blasted with Large Grit and Acid Etched Dental Implant". Advanced Materials Research 647 (styczeń 2013): 80–87. http://dx.doi.org/10.4028/www.scientific.net/amr.647.80.
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The purpose of this study was to apply nanotechnology to dental implant for improved osseointegration. Titania nanostructures were fabricated on the sand blasted with large grit and acid etched (SA) titanium (ASTM grade 4) implants (TSIII SA®, Osstem, 3.5 x 5 mm) using potentiostatic anodic oxidation in HF. The nanostructures were uniformly formed on the SA surface. The mean pore size of nanostructure was about 30 nm. In the result of torque test, the nanostructure formed on SA surface was preserved from the torque, even after the loading of 40Ncm. An amorphous titania nanostructure was annealed at 400 °C. Through heat treatment, the amorphous titania nanostructure was turned into anatase phase. Hydrofluoric acid was used as the electrolyte to form nanostructure. In the result of ion release test, however, fluoride ions were not detected at the heat treated group. Therefore, such nanostructured SA implant (Nano-SA) will be suitable for dental implant.
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Cho, Seong J., Se Yeong Seok, Jin Young Kim, Geunbae Lim i Hoon Lim. "One-Step Fabrication of Hierarchically Structured Silicon Surfaces and Modification of Their Morphologies Using Sacrificial Layers". Journal of Nanomaterials 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/289256.
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Fabrication of one-dimensional nanostructures is a key issue for optical devices, fluidic devices, and solar cells because of their unique functionalities such as antireflection and superhydrophobicity. Here, we report a novel one-step process to fabricate patternable hierarchical structures consisting of microstructures and one-dimensional nanostructures using a sacrificial layer. The layer plays a role as not only a micromask for producing microstructures but also as a nanomask for nanostructures according to the etching time. Using this method, we fabricated patterned hierarchical structures, with the ability to control the shape and density of the nanostructure. The various architectures provided unique functionalities. For example, our sacrificial-layer etching method allowed nanostructures denser than what would be attainable with conventional processes to form. The dense nanostructure resulted in a very low reflectance of the silicon surface (less than 1%). The nanostructured surface and hierarchically structured surface also exhibited excellent antiwetting properties, with a high contact angle (>165°) and low sliding angle (<1°). We believe that our fabrication approach will provide new insight into functional surfaces, such as those used for antiwetting and antireflection surface applications.
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Reddy, G. S., Mallikarjuna N. Nadagouda i Jainagesh A. Sekhar. "Nanostructured Surfaces that Show Antimicrobial, Anticorrosive, and Antibiofilm Properties". Key Engineering Materials 521 (sierpień 2012): 1–33. http://dx.doi.org/10.4028/www.scientific.net/kem.521.1.
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Provided in this article are the quantitative and qualitative morphological results describing the action of several nanostructured surfaces for bactericidal and bacteriostatic action. Results are also provided to illustrate microbial corrosion and its impact. Biofilm formation is correlated to colony formation. Nanostructured surfaces, i.e. surfaces with welded nanoparticles are noted to display biocidal activity with varying efficacies. Porous nanostructures, on stainless steel and copper substrates, made of high purity Ag, Ti, Al, Cu, MoSi2, and carbon nanotubes, are tested for their efficacy against bacterial colony formation for both gram-negative, and gram-positive bacteria. Silver and Molybdenum disilicide (MoSi2) nanostructures are found to be the most effective bactericidal agents with MoSi2 being particularly effective in both low and high humidity conditions. Bacteriostatic activity is also noted. The nanostructured surfaces are tested by controlled exposures to several microbial species including (Gram+ve) bacteria such as Bacillus Cereus and (Gram-ve) bacteria such as Enterobacter Aerogenes. The resistance to simultaneous exposure from diverse bacterial species including Arthrobacter Globiformis, Bacillus Megaterium, and Cupriavidus Necator is also studied. The nanostructured surfaces were found to eliminates or delay bacterial colony formation, even with short exposure times, and even after simulated surface abrasion. The virgin 316 stainless steel and copper substrates, i.e. without the nanostructure, always displayed rapid bacterial colony evolution indicating the lack of antimicrobial action. The efficacy of the nanostructured surface against colony formation (bacterial recovery) for E-Coli (two strains) and virus Phi 6 Bacteriophage with a host Pseudomonas Syringae was also studied. Preliminary results are presented that also show possible anti-fungal properties by the nanostructured MoSi2. When comparing antimicrobial efficacy of flat polished surfaces (no curvature or nanostructure) with nanostructure containing surfaces (high curvature) of the same chemistry, shows that bacterial action results from both the nanostructure size and chemistry.
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Wu, Xin, Xianrui Zou, Donghui Wang, Mingjun Li, Bo Zhao, Yi Xia, Hongshui Wang i Chunyong Liang. "Revealing the Mechanical Impact of Biomimetic Nanostructures on Bacterial Behavior". Coatings 14, nr 7 (9.07.2024): 860. http://dx.doi.org/10.3390/coatings14070860.
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Naturally inspired nanostructured surfaces, by mechanically inhibiting bacterial adhesion or killing bacteria, effectively prevent the emergence of antibiotic resistance, making them a promising strategy against healthcare-associated infections. However, the current mechanical antibacterial mechanism of nanostructures is not clear, thus limiting their potential application in medical devices. This work mainly investigates the mechanical influence mechanism of biomimetic nanostructure parameters on bacterial adhesion and growth status. The results of 12 h bacterial culture showed that compared to flat surfaces, nanostructures reduced the adhesion of both E. coli and S. aureus bacteria by 49%~82%. The bactericidal efficiency against E. coli increased by 5.5%~31%, depending on the shape of the nanostructures. Nanostructures with smaller tip diameters exhibited the best anti-bacterial adhesion effects. Nanostructures with sharp tips and larger interspaces showed greater bactericidal effects against E. coli. Surfaces with larger tip diameters had the poorest antibacterial effects. Subsequently, a finite element model was established to quantitatively analyze the mechanical interactions between bacteria and nanostructures. It was found that different nanostructures affect bacterial adhesion and growth by altering the contact area with bacteria and inducing stress and deformation on the cell wall. Nanostructures with smaller tip diameters reduced the attachment area to bacteria, thereby reducing bacterial adhesion strength. Nanostructures with larger interspaces induced greater stress and deformation on the cell wall, thereby enhancing bactericidal efficiency. Finally, experimental verification with L929 cells confirmed that nanostructures do not cause mechanical damage to the cells. These studies deepen our understanding of the antibacterial mechanism of biomimetic nanostructures and provide new insights for the design of optimal nanostructures.
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Subki, A. Shamsul Rahimi A., Mohamad Hafiz Mamat, Musa Mohamed Zahidi, Mohd Hanapiah Abdullah, I. B. Shameem Banu, Nagamalai Vasimalai, Mohd Khairul Ahmad i in. "Optimization of Aluminum Dopant Amalgamation Immersion Time on Structural, Electrical, and Humidity-Sensing Attributes of Pristine ZnO for Flexible Humidity Sensor Application". Chemosensors 10, nr 11 (17.11.2022): 489. http://dx.doi.org/10.3390/chemosensors10110489.
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This study synthesized pristine and aluminum (Al)-doped zinc oxide (Al:ZnO) nanostructures through a simplistic low-temperature ultrasonicated solution immersion method. Al:ZnO nanostructures were synthesized as a sensing material using different immersion times varying from two to five hours. The Al:ZnO nanostructured-based flexible humidity sensor was fabricated by employing cellulose filter paper as a substrate and transparent paper glue as a binder through a simplistic brush printing technique. XRD, FESEM, HRTEM, EDS, XPS, a two-probe I–V measurement system, and a humidity measurement system were employed to investigate the structural, morphological, chemical, electrical, and humidity-sensing properties of the pristine ZnO and Al:ZnO nanostructures. The structural and morphological analysis confirmed that Al cations successfully occupied the Zn lattice or integrated into interstitial sites of the ZnO lattice matrix. Humidity-sensing performance analysis indicated that the resistance of the Al:ZnO nanostructure samples decreased almost linearly as the humidity level increased, leading to better sensitivity and sensing response. The Al:ZnO-4 h nanostructured-based flexible humidity sensor had a maximum sensing response and demonstrated the highest sensitivity towards humidity changes, which was noticeably superior to the other tested samples. Finally, this study explained the Al:ZnO nanostructures-based flexible humidity sensor sensing mechanism in terms of chemical adsorption, physical adsorption, and capillary condensation mechanisms.
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Sen, Dipanjan, i Markus J. Buehler. "Shock Loading of Bone-Inspired Metallic Nanocomposites". Solid State Phenomena 139 (kwiecień 2008): 11–22. http://dx.doi.org/10.4028/www.scientific.net/ssp.139.11.
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Nanostructured composites inspired by structural biomaterials such as bone and nacre form intriguing design templates for biomimetic materials. Here we use large scale molecular dynamics to study the shock response of nanocomposites with similar nanoscopic structural features as bone, to determine whether bioinspired nanostructures provide an improved shock mitigating performance. The utilization of these nanostructures is motivated by the toughness of bone under tensile load, which is far greater than its constituent phases and greater than most synthetic materials. To facilitate the computational experiments, we develop a modified version of an Embedded Atom Method (EAM) alloy multi-body interatomic potential to model the mechanical and physical properties of dissimilar phases of the biomimetic bone nanostructure. We find that the geometric arrangement and the specific length scales of design elements at nanoscale does not have a significant effect on shock dissipation, in contrast to the case of tensile loading where the nanostructural length scales strongly influence the mechanical properties. We find that interfacial sliding between the composite’s constituents is a major source of plasticity under shock loading. Based on this finding, we conclude that controlling the interfacial strength can be used to design a material with larger shock absorption. These observations provide valuable insight towards improving the design of nanostructures in shock-absorbing applications, and suggest that by tuning the interfacial properties in the nanocomposite may provide a path to design materials with enhanced shock absorbing capability.
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Erb, Denise J., Kai Schlage i Ralf Röhlsberger. "Uniform metal nanostructures with long-range order via three-step hierarchical self-assembly". Science Advances 1, nr 10 (listopad 2015): e1500751. http://dx.doi.org/10.1126/sciadv.1500751.
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Large-scale nanopatterning is a major issue in nanoscience and nanotechnology, but conventional top-down approaches are challenging because of instrumentation and process complexity while often lacking the desired spatial resolution. We present a hierarchical bottom-up nanopatterning routine using exclusively self-assembly processes: By combining crystal surface reconstruction, microphase separation of copolymers, and selective metal diffusion, we produce monodisperse metal nanostructures in highly regular arrays covering areas of square centimeters. In situ grazing incidence small-angle x-ray scattering during Fe nanostructure formation evidences an outstanding structural order in the self-assembling system and hints at the possibility of sculpting nanostructures using external process parameters. Thus, we demonstrate that bottom-up nanopatterning is a competitive alternative to top-down routines, achieving comparable pattern regularity, feature size, and patterned areas with considerably reduced effort. Intriguing assets of the proposed fabrication approach include the option for in situ investigations during pattern formation, the possibility of customizing the nanostructure morphology, the capacity to pattern arbitrarily large areas with ultrahigh structure densities unachievable by top-down approaches, and the potential to address the nanostructures individually. Numerous applications of self-assembled nanostructure patterns can be envisioned, for example, in high-density magnetic data storage, in functional nanostructured materials for photonics or catalysis, or in surface plasmon resonance–based sensing.
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Mezinskis, Gundars, Darja Larionova, Arturs Pludons i Liga Grase. "Influence of Substrate Preparation Method on the Morphologies of TiO2 Sol-Gel Derived Coatings". Advanced Materials Research 1117 (lipiec 2015): 143–46. http://dx.doi.org/10.4028/www.scientific.net/amr.1117.143.
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Most studies devoted to the development of nanostructured TiO2 coatings focus mainly on the nanostructures obtained and bulk properties of material. Nanostructured TiO2 sol-gel films were prepared on a mechanic-chemical and ultrasound cleaned glass substrates. Atomic force and field emission scanning electron microscopy results confirmed fast contamination of cleaned substrates. The analysis of obtained results indicated that soda-lime silicate glass substrate cleaning method could be used to tailor the formation of TiO2 sol-gel coatings nanostructure.
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Gnawali, Guna Nidha, Shankar P. Shrestha, Khem N. Poudyal, Indra B. Karki i Ishwar Koirala. "Study on the effect of growth-time and seed-layers of Zinc Oxide nanostructured thin film prepared by the hydrothermal method for liquefied petroleum gas sensor application". BIBECHANA 16 (22.11.2018): 145–53. http://dx.doi.org/10.3126/bibechana.v16i0.21557.
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Gas sensors are devices that can convert the concentration of an analytic gas into an electronic signal. Zinc oxide (ZnO) is an important n-type metal oxide semiconductor which has been utilized as gas sensor for several decades. In this work, ZnO nanostructured films were synthesized by a hydrothermal route from ZnO seeds and used as a liquefied petroleum gas (LPG) sensor. At first ZnO seed layers were deposited on glass substrates by using spin coating method, then ZnO nanostructured were grown on these substrates by using hydrothermal growth method for different time duration. The effect of growth time and seed layers of ZnO nanostructured on its structural, optical, and electrical properties was studied. These nanostructures were characterized by X-ray diffraction, scanning electron microscopy, optical spectroscopy, and four probes sheet resistance measurement unit. The sensing performances of the synthetic ZnO nanostructures were investigated for LPG.XRD showed that all the ZnO nanostructures were hexagonal crystal structure with preferential orientation. SEM reviled that the size of nanostructure increased with increase in growth time. Band gap and sheet resistance for ZnO nanostructured thin film decreased with increase in growth time. ZnO nanostructured thin film showed high sensitivity towards LPG gas. The sensitivity of the film is observed to increase with increase in no of seed layers as well as growth time. The dependence of the LPG sensing properties on the different growth time of ZnO nanostructured was investigated. The sensing performances of the film were investigated by measured change in sheet resistance under expose to LPG gas. BIBECHANA 16 (2019) 145-153
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Lee, Jinho, Donghwi Cho, Haomin Chen, Young-Seok Shim, Junyong Park i Seokwoo Jeon. "Proximity-field nanopatterning for high-performance chemical and mechanical sensor applications based on 3D nanostructures". Applied Physics Reviews 9, nr 1 (marzec 2022): 011322. http://dx.doi.org/10.1063/5.0081197.
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In this era of the Internet of Things, the development of innovative sensors has rapidly accelerated with that of nanotechnology to accommodate various demands for smart applications. The practical use of three-dimensional (3D) nanostructured materials breaks several limitations of conventional sensors, including the large surface-to-volume ratio, precisely tunable pore size and porosity, and efficient signal transduction of 3D geometries. This review provides an in-depth discussion on recent advances in chemical and mechanical sensors based on 3D nanostructures, which are rationally designed and manufactured by advanced 3D nanofabrication techniques that consider structural factors (e.g., porosity, periodicity, and connectivity). In particular, we focus on a proximity-field nanopatterning technique that specializes in the production of periodic porous 3D nanostructures that satisfy the structural properties universally required to improve the performance of various sensor systems. State-of-the-art demonstrations of high-performance sensor devices such as supersensitive gas sensors and wearable strain sensors realized through designed 3D nanostructures are summarized. Finally, challenges and outlooks related to nanostructures and nanofabrication for the practical application of 3D nanostructure-based sensor systems are proposed.
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Rani, B. Jansi, M. Praveenkumar, S. Ravichandran, G. Ravi, Ramesh K. Guduru i R. Yuvakkumar. "BiVO4 Nanostructures for Photoelectrochemical (PEC) Solar Water Splitting Applications". Journal of Nanoscience and Nanotechnology 19, nr 11 (1.11.2019): 7427–35. http://dx.doi.org/10.1166/jnn.2019.16642.
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We reported a simple and economical SDS (sodium dodecyl sulfate) assisted BiVO4 solvothermal synthesis of BiVO4 nanostructures. The implementation of pristine and SDS assisted BiVO4 nanostructure as photoanode in photoelectrochemical (PEC) water splitting was investigated. The good crystalline nature, defects present in the material, recombination nature and vibrational properties of the synthesized BiVO4 nanostructures have been analyzed and confirmed by XRD, Raman, PL and FTIR studies. The constructed nanoflower oriented morphology combined with nanorods for SDS assisted BiVO4 have been examined by SEM studies. The optical band gap differences were observed as 2.35 and 2.31 eV for pristine and SDS assisted BiVO4 nanostructures respectively. The higher photocurrent density of 5.8 μA/cm2 at 0.5 V versus RHE with lower flat band potential of -0.75 V revealed for SDS assisted BiVO4 nanostructured photoanodes. Good conductivity, higher charge separation efficiency and 52% photocurrent retention under illumination was reported over 7200 s for the same efficient photoanode. These results suggested the substantial possibility of BiVO4 nanostructures synthesized by using SDS surfactant could be utilized as efficient photoanodes for PEC water splitting applications.
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Neustock, Lars Thorben, Sabrina Jahns, Jost Adam i Martina Gerken. "Optical Waveguides with Compound Multiperiodic Grating Nanostructures for Refractive Index Sensing". Journal of Sensors 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/6174527.
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The spectral characteristics and refractive index sensitivity of compound multiperiodic grating waveguides are investigated in theory and experiment. Compound gratings are formed by superposition of two or more monoperiodic gratings. Compared to monoperiodic photonic crystal waveguides, compound grating waveguides offer more degrees of design freedom by choice of component grating periods and duty cycles. Refractive index sensing is achieved by evaluating the wavelength or intensity of guided mode resonances in the reflection spectrum. We designed, fabricated, and characterized 24 different compound multiperiodic nanostructured waveguides for refractive index sensing. Simulations are carried out with the Rigorous Coupled Wave Algorithm (RCWA). The resulting spectra, resonance sensitivities, and quality factors are compared to monoperiodic as well as to three selected aperiodic nanostructures (Rudin-Shapiro, Fibonacci, and Thue-Morse). The refractive index sensitivity of the TE resonances is similar for all types of investigated nanostructures. For the TM resonances the compound multiperiodic nanostructures exhibit higher sensitivity values compared to the monoperiodic nanostructure and similar values as the aperiodic nanostructures. No significant influence of the compound grating duty cycles on the sensitivity is observed.
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Mendes, Rafael, Paweł Wróbel, Alicja Bachmatiuk, Jingyu Sun, Thomas Gemming, Zhongfan Liu i Mark Rümmeli. "Carbon Nanostructures as a Multi-Functional Platform for Sensing Applications". Chemosensors 6, nr 4 (5.12.2018): 60. http://dx.doi.org/10.3390/chemosensors6040060.
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The various forms of carbon nanostructures are providing extraordinary new opportunities that can revolutionize the way gas sensors, electrochemical sensors and biosensors are engineered. The great potential of carbon nanostructures as a sensing platform is exciting due to their unique electrical and chemical properties, highly scalable, biocompatible and particularly interesting due to the almost infinite possibility of functionalization with a wide variety of inorganic nanostructured materials and biomolecules. This opens a whole new pallet of specificity into sensors that can be extremely sensitive, durable and that can be incorporated into the ongoing new generation of wearable technology. Within this context, carbon-based nanostructures are amongst the most promising structures to be incorporated in a multi-functional platform for sensing. The present review discusses the various 1D, 2D and 3D carbon nanostructure forms incorporated into different sensor types as well as the novel functionalization approaches that allow such multi-functionality.
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Chen, Yusi, Yangsen Kang, Jieyang Jia, Yijie Huo, Muyu Xue, Zheng Lyu, Dong Liang, Li Zhao i James S. Harris. "Nanostructured Dielectric Layer for Ultrathin Crystalline Silicon Solar Cells". International Journal of Photoenergy 2017 (2017): 1–6. http://dx.doi.org/10.1155/2017/7153640.
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Nanostructures have been widely used in solar cells due to their extraordinary photon management properties. However, due to poor pn junction quality and high surface recombination velocity, typical nanostructured solar cells are not efficient compared with the traditional commercial solar cells. Here, we demonstrate a new approach to design, simulate, and fabricate whole-wafer nanostructures on dielectric layer on thin c-Si for solar cell light trapping. The optical simulation results show that the periodic nanostructure arrays on dielectric materials could suppress the reflection loss over a wide spectral range. In addition, by applying the nanostructured dielectric layer on 40 μm thin c-Si, the reflection loss is suppressed to below 5% over a wide spectra and angular range. Moreover, a c-Si solar cell with 2.9 μm ultrathin absorber layer demonstrates 32% improvement in short circuit current and 44% relative improvement in energy conversion efficiency. Our results suggest that nanostructured dielectric layer has the potential to significantly improve solar cell performance and avoid typical problems of defects and surface recombination for nanostructured solar cells, thus providing a new pathway towards realizing high-efficiency and low-cost c-Si solar cells.
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Aseev, Aleksander Leonidovich, Alexander Vasilevich Latyshev i Anatoliy Vasilevich Dvurechenskii. "Semiconductor Nanostructures for Modern Electronics". Solid State Phenomena 310 (wrzesień 2020): 65–80. http://dx.doi.org/10.4028/www.scientific.net/ssp.310.65.
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Modern electronics is based on semiconductor nanostructures in practically all main parts: from microprocessor circuits and memory elements to high frequency and light-emitting devices, sensors and photovoltaic cells. Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) with ultimately low gate length in the order of tens of nanometers and less is nowadays one of the basic elements of microprocessors and modern electron memory chips. Principally new physical peculiarities of semiconductor nanostructures are related to quantum effects like tunneling of charge carriers, controlled changing of energy band structure, quantization of energy spectrum of a charge carrier and a pronounced spin-related phenomena. Superposition of quantum states and formation of entangled states of photons offers new opportunities for the realization of quantum bits, development of nanoscale systems for quantum cryptography and quantum computing. Advanced growth techniques such as molecular beam epitaxy and chemical vapour epitaxy, atomic layer deposition as well as optical, electron and probe nanolithography for nanostructure fabrication have been widely used. Nanostructure characterization is performed using nanometer resolution tools including high-resolution, reflection and scanning electron microscopy as well as scanning tunneling and atomic force microscopy. Quantum properties of semiconductor nanostructures have been evaluated from precise electrical and optical measurements. Modern concepts of various semiconductor devices in electronics and photonics including single-photon emitters, memory elements, photodetectors and highly sensitive biosensors are developed very intensively. The perspectives of nanostructured materials for the creation of a new generation of universal memory and neuromorphic computing elements are under lively discussion. This paper is devoted to a brief description of current achievements in the investigation and modeling of single-electron and single-photon phenomena in semiconductor nanostructures, as well as in the fabrication of a new generation of elements for micro-, nano, optoelectronics and quantum devices.
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Chen, Huige, Run Shi i Tierui Zhang. "Nanostructured Photothermal Materials for Environmental and Catalytic Applications". Molecules 26, nr 24 (13.12.2021): 7552. http://dx.doi.org/10.3390/molecules26247552.
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Solar energy is a green and sustainable clean energy source. Its rational use can alleviate the energy crisis and environmental pollution. Directly converting solar energy into heat energy is the most efficient method among all solar conversion strategies. Recently, various environmental and energy applications based on nanostructured photothermal materials stimulated the re-examination of the interfacial solar energy conversion process. The design of photothermal nanomaterials is demonstrated to be critical to promote the solar-to-heat energy conversion and the following physical and chemical processes. This review introduces the latest photothermal nanomaterials and their nanostructure modulation strategies for environmental (seawater evaporation) and catalytic (C1 conversion) applications. We present the research progress of photothermal seawater evaporation based on two-dimensional and three-dimensional porous materials. Then, we describe the progress of photothermal catalysis based on layered double hydroxide derived nanostructures, hydroxylated indium oxide nanostructures, and metal plasmonic nanostructures. Finally, we present our insights concerning the future development of this field.
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Shen, Shaohua, i Samuel S. Mao. "Nanostructure designs for effective solar-to-hydrogen conversion". Nanophotonics 1, nr 1 (1.07.2012): 31–50. http://dx.doi.org/10.1515/nanoph-2012-0010.
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AbstractConversion of energy from photons in sunlight to hydrogen through solar splitting of water is an important technology. The rising significance of producing hydrogen from solar light via water splitting has motivated a surge of developing semiconductor solar-active nanostructures as photocatalysts and photoelectrodes. Traditional strategies have been developed to enhance solar light absorption (e.g., ion doping, solid solution, narrow-band-gap semiconductor or dye sensitization) and improve charge separation/transport to prompt surface reaction kinetics (e.g., semiconductor combination, co-catalyst loading, nanostructure design) for better utilizing solar energy. However, the solar-to-hydrogen efficiency is still limited. This article provides an overview of recently demonstrated novel concepts of nanostructure designs for efficient solar hydrogen conversion, which include surface engineering, novel nanostructured heterojunctions, and photonic crystals. Those first results outlined in the main text encouragingly point out the prominence and promise of these new concepts principled for designing high-efficiency electronic and photonic nanostructures that could serve for sustainable solar hydrogen production.
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Hu, Zeyi, Wenliang Liu i Caihe Fan. "Micro-Nanostructure Formation Mechanism of High-Mg Al Alloy". Nanoscience and Nanotechnology Letters 11, nr 10 (1.10.2019): 1338–48. http://dx.doi.org/10.1166/nnl.2019.3016.
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Micro-nanostructured materials have superior mechanical properties compared with coarse-grained materials. Severe plastic deformation (SPD) can effectively refine grains, resulting in the formation of typical micro-nanostructures. Fine grains improve alloy strength and toughness. This review summarizes the application of several typical SPD methods for high-Mg Al alloy. The effects of different SPD methods on the microstructure evolution, micro-nanostructure formation mechanism, and mechanical properties of the high-Mg Al alloy are analyzed in sequence. Finally, the development and future of the high-Mg Al alloy micro/nanostructure regulation are described.
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Salvat-Pujol, Francesc, Harald O. Jeschke i Roser Valentí. "Simulation of electron transport during electron-beam-induced deposition of nanostructures". Beilstein Journal of Nanotechnology 4 (22.11.2013): 781–92. http://dx.doi.org/10.3762/bjnano.4.89.
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We present a numerical investigation of energy and charge distributions during electron-beam-induced growth of tungsten nanostructures on SiO2 substrates by using a Monte Carlo simulation of the electron transport. This study gives a quantitative insight into the deposition of energy and charge in the substrate and in the already existing metallic nanostructures in the presence of the electron beam. We analyze electron trajectories, inelastic mean free paths, and the distribution of backscattered electrons in different compositions and at different depths of the deposit. We find that, while in the early stages of the nanostructure growth a significant fraction of electron trajectories still interacts with the substrate, when the nanostructure becomes thicker the transport takes place almost exclusively in the nanostructure. In particular, a larger deposit density leads to enhanced electron backscattering. This work shows how mesoscopic radiation-transport techniques can contribute to a model that addresses the multi-scale nature of the electron-beam-induced deposition (EBID) process. Furthermore, similar simulations can help to understand the role that is played by backscattered electrons and emitted secondary electrons in the change of structural properties of nanostructured materials during post-growth electron-beam treatments.
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Hariharalakshmanan, Ranjitha K., Fumiya Watanabe i Tansel Karabacak. "In Situ Growth and UV Photocatalytic Effect of ZnO Nanostructures on a Zn Plate Immersed in Methylene Blue". Catalysts 12, nr 12 (16.12.2022): 1657. http://dx.doi.org/10.3390/catal12121657.
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Nanostructures of zinc oxide (ZnO) are considered promising photocatalysts for the degradation of organic pollutants in water. This work discusses an in situ growth and UV photocatalytic effect of ZnO nanostructures on a Zn plate immersed in methylene blue (MB) at room temperature. First, the Zn surfaces were pretreated via sandblasting to introduce a micro-scale roughness. Then, the Zn plates were immersed in MB and exposed to UV light, to observe ZnO nanostructure growth and photocatalytic degradation of MB. Scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectroscopy were used to characterize the Zn surfaces. We observed the growth of stoichiometric and crystalline ZnO with a nano-leaf morphology and an estimated bandgap of 3.08 eV. The photocatalytic degradation of MB was also observed in the presence of the ZnO nanostructures and UV light. The average percentage degradation was 76% in 4 h, and the degradation rate constant was 0.3535 h−1. The experimental results suggest that room temperature growth of ZnO nanostructures (on Zn surfaces) in organic dye solutions is possible. Furthermore, the nanostructured surface can be used simultaneously for the photocatalytic degradation of the organic dye.
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Chen, Hongjun, i Lianzhou Wang. "Nanostructure sensitization of transition metal oxides for visible-light photocatalysis". Beilstein Journal of Nanotechnology 5 (23.05.2014): 696–710. http://dx.doi.org/10.3762/bjnano.5.82.
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To better utilize the sunlight for efficient solar energy conversion, the research on visible-light active photocatalysts has recently attracted a lot of interest. The photosensitization of transition metal oxides is a promising approach for achieving effective visible-light photocatalysis. This review article primarily discusses the recent progress in the realm of a variety of nanostructured photosensitizers such as quantum dots, plasmonic metal nanostructures, and carbon nanostructures for coupling with wide-bandgap transition metal oxides to design better visible-light active photocatalysts. The underlying mechanisms of the composite photocatalysts, e.g., the light-induced charge separation and the subsequent visible-light photocatalytic reaction processes in environmental remediation and solar fuel generation fields, are also introduced. A brief outlook on the nanostructure photosensitization is also given.
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Lowe, Terry C. "Enhancing Fatigue Properties of Nanostructured Metals and Alloys". Advanced Materials Research 29-30 (listopad 2007): 117–22. http://dx.doi.org/10.4028/www.scientific.net/amr.29-30.117.
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Recent research on the fatigue properties of nanostructured metals and alloys has shown that they generally possess superior high cycle fatigue performance due largely to improved resistance to crack initiation. However, this advantage is not consistent for all nanostructured metals, nor does it extend to low cycle fatigue. Since nanostructures are designed and controlled at the approximately the same size scale as the defects that influence crack initiation attention to preexisting nanoscale defects is critical for enhancing fatigue life. This paper builds on the state of knowledge of fatigue in nanostructured metals and proposes an approach to understand and improve fatigue life using existing experimental and computational methods for nanostructure design.
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Широкий, Ю. В. "ВИЗНАЧЕННЯ ВПЛИВУ ВНУТРІШНІХ ЕНЕРГІЙ КРИСТАЛІЧНОЇ РЕШІТКИ НА ОТРИМАННЯ НАНОСТРУКТУР У ПОВЕРХНЕВИХ ШАРАХ АЛЮМІНІЄВИХ СПЛАВІВ". Open Information and Computer Integrated Technologies, nr 99 (24.06.2024): 32–43. http://dx.doi.org/10.32620/oikit.2023.99.03.
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The paper presents the results of calculating the crystallization energy and examines its influence on the size of the nanostructured grain during ion-plasma treatment of aluminum (VD17) with oxygen and nitrogen ions. To address this task, we employ a previously proposed model, which considers the impact of individual ions on thermal conductivity and thermoelasticity in the affected area, taking into account their energy, charge, and type. Initially, we estimate the potential number of particles in the nanostructure. Then, we compute the energy required for atomizing the grain from atoms and chemical compounds. By determining the total atomization energy of the grain (Eas), we establish the necessary energy for its formation (Es = 1.1Eas). This energy enables the determination of all characteristics in the ion's action area, such as temperature, temperature rise rate, thermal stresses, strain rate, grain size, volume, and depth of the nanostructure, as well as the actual number of particles in the nanostructure. The calculations demonstrate that the crystallization energy increases the ion energy required to obtain nanostructures. At energies close to 3∙102 eV, it ranges from 0.1 to 7 eV, which can be disregarded, while at energies close to 1.6∙104 eV, crystallization energy ranges from 2.1∙102 to 1.2∙104 eV, with higher values for oxygen ions. Additionally, the calculations show that ion charge significantly affects crystallization energy; for large ion charges, it increases. All of this underscores the necessity of considering crystallization energy only at energies of 2∙103 – 2∙104 eV, allowing refinement of the technological parameters of ion-plasma treatment of aluminum alloys to increase the likelihood of obtaining nanostructures. Furthermore, the ability to determine the sizes of nanostructures allows predicting the physical and mechanical characteristics of surface layers of processed materials. These studies may be of interest to specialists involved in surface strengthening of aluminum alloy surfaces and further research into nanostructures
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Schuller, Ivan K. "Unusual Phenomena in Exchange-Biased Nanostructures". MRS Bulletin 29, nr 9 (wrzesień 2004): 642–46. http://dx.doi.org/10.1557/mrs2004.184.
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AbstractThe following article is an edited transcript based on the MRS Medalist presentation given by Ivan K.Schuller of the University of California, San Diego, on December 3, 2003, at the Materials Research Society Fall Meeting in Boston.Schuller received the MRS Medal for “his innovative studies of exchange bias in magnetic heterostructures and nanostructures.” Magnetic nanostructures have received increasing attention in recent years, motivated by the interesting phenomena that are apparent when physical size becomes comparable with relevant magnetic length scales.In addition, a number of important potential applications in the sensors and storage industries have emerged. When magnetic nanostructures are in contact with dissimilar magnetic materials, and because their magnetic fields extend considerably outside the physical structure, they are very susceptible to interaction with the surrounding environment.A particularly interesting situation is a ferromagnetic nanostructure in contact with an anti-ferromagnetic substrate.In this “exchange-biased” configuration, a variety of unusual phenomena arise:The reversal mode of the ferromagnet changes considerably, the superparamagnetic transition temperature is affected, and there is a noticeable change in the microscopic spin configuration.A series of experiments will be described involving these phenomena in nanostructured ferromagnets prepared by electron-beam lithography and self-assembly.
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Spontak, R. J., H. Jinnai, M. B. Braunfeld i D. A. Agard. "Quantitative Transmission Electron Microtomography of Complex Bicontinuous Polymer Nanostructures". Microscopy and Microanalysis 6, S2 (sierpień 2000): 1128–29. http://dx.doi.org/10.1017/s1431927600038137.
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Nanostructured polymers constitute an increasingly important class of materials. Investigations into the formation of nanostructural elements in microphase-ordered block copolymers have elucidated universal mechanisms of self-organization in soft-condensed matter, since topologically comparable nanostructures develop in biological and surfactant systems. Emerging applications of such polymers include nanotemplates for inorganic materials, optical switches and nanoreactors. Despite all the efforts that have focused on these materials in previous years, basic questions regarding the characteristics of these nanostructures, especially those exhibiting bicontinuity, persist. While most attempts to address these questions have relied on small-angle scattering, a real-space approach to this problem compares slices of simulated nanostructures to 2-D transmission electron microscopy (TEM) images. An alternate strategy is transmission electron microtomography (TEMT), which utilizes 3-D images (reconstructed from a series of 2-D images collected at sequential tilt angles) for detailed structural analysis. Using this method, we have, for instance, recently confirmed that packing frustration,
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Guo, Wenting, Liangcai Zeng i Zhuoyuan Liu. "Mechanism of Surface Wettability of Nanostructure Morphology Enhancing Boiling Heat Transfer: Molecular Dynamics Simulation". Processes 11, nr 3 (13.03.2023): 857. http://dx.doi.org/10.3390/pr11030857.
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In this paper, the interaction mechanism between the solid–liquid–gas interface phenomenon caused by nanostructure and surface wettability and boiling heat transfer is described, and the heat transfer theory of single wettable nanostructure surface and mixed wettable nanostructure surface is proposed. Through molecular dynamics simulation, the thermodynamic model of the wettable surface of nanostructures is established. The nanostructures are set as four rectangular lattice structures with a height of 18 Å. The solid atoms are platinum atoms, and the liquid atoms are argon atoms. The simulation results show that with the increase of surface hydrophilicity of nanostructures, the fluid temperature increases significantly, and the heat transfer at the interface is enhanced. With the increase in surface hydrophobicity of nanostructures, the atoms staying on the surface of nanostructures are affected by the hydrophobicity, showing a phenomenon of exclusion, and the evaporation rate in the evaporation area of nanostructures is significantly increased. In addition, the mixed wettable surface is influenced by the atomic potential energy and kinetic energy of the solid surface, and when compared with the pure wettable surface under the nanostructure, it changes the diffusion behavior of argon atoms on the nanostructure surface, enhances the heat transfer phenomenon compared with the pure hydrophobic surface, and enhances the evaporation phenomenon compared with the pure hydrophilic surface. This study provides insights into the relationship between the vapor film and the heating surface with mixed wettability and nanostructures.
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Rajbongshi, Himanshu, i Dipjyoti Kalita. "Morphology-Dependent Photocatalytic Degradation of Organic Pollutant and Antibacterial Activity with CdS Nanostructures". Journal of Nanoscience and Nanotechnology 20, nr 9 (1.09.2020): 5885–95. http://dx.doi.org/10.1166/jnn.2020.18552.
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Efficient removal of organic pollutants from waste water by nanostructured photocatalysts has become an emerging research due to its importance in environmental remediation. Herein, CdS nanostructures with different morphologies i.e., spherical, nanopetal and rose-like have been synthesized by wet chemical method using TEA as a structure directing agent. The morphology, crystal structure, composition, surface area and optical properties of the nanostructures are investigated by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), Brunauer-Emment-Teller (BET) analyser, Ultraviolet-Visible (UV-Vis) absorption spectroscopy and Photoluminescence (PL) spectroscopy. XRD patterns indicate the existence of hexagonal phase of CdS in all the three morphologies. The SEM images confirm the morphological transformation of spherical CdS nanoparticles (NPs) to nanopetal and rose-like morphology with the increase in concentration of TEA in the synthesis process. UV-visible absorption spectra show that rose-like CdS nanostructure exhibits red-shift of absorption wavelength compared to spherical and nanopetal CdS nanostructures. The increase in intensity of PL peak of rose-like CdS at 576.6 nm compared to that of spherical and nanopetal CdS, confirms the presence of more S vacancies or defect states. The BET specific surface areas of spherical, nanopetal and rose-like CdS nanostructures are determined to be 4.18, 6.64 and 8.93 m2/g, respectively. The EIS Nyquist plot confirms the higher electron transfer efficiency of rose-like CdS than that of spherical and nanopetal CdS. The photocatalytic activity of these three nanostructures are evaluated for the degradation of methylene blue (MB) dye in water solution under sunlight irradiation. Among the three structures, rose-like CdS nanostructure shows highest photocatalytic efficiency (96.5%) under sunlight irradiation within 120 min of sunlight irradiation. Antibacterial activity of the synthesized CdS nanostructures is performed against two Gram-positive and Gram-negative bacteria and rose-like CdS shows more activity against both types of bacteria than that of spherical and nanopetal CdS.
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Liu, Kai, Zhun Qiao i Chuanbo Gao. "Preventing the Galvanic Replacement Reaction toward Unconventional Bimetallic Core–Shell Nanostructures". Molecules 28, nr 15 (28.07.2023): 5720. http://dx.doi.org/10.3390/molecules28155720.
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A bimetallic core–shell nanostructure is a versatile platform for achieving intriguing optical and catalytic properties. For a long time, this core–shell nanostructure has been limited to ones with noble metal cores. Otherwise, a galvanic replacement reaction easily occurs, leading to hollow nanostructures or completely disintegrated ones. In the past few years, great efforts have been devoted to preventing the galvanic replacement reaction, thus creating an unconventional class of core–shell nanostructures, each containing a less-stable-metal core and a noble metal shell. These new nanostructures have been demonstrated to show unique optical and catalytic properties. In this work, we first briefly summarize the strategies for synthesizing this type of unconventional core–shell nanostructures, such as the delicately designed thermodynamic control and kinetic control methods. Then, we discuss the effects of the core–shell nanostructure on the stabilization of the core nanocrystals and the emerging optical and catalytic properties. The use of the nanostructure for creating hollow/porous nanostructures is also discussed. At the end of this review, we discuss the remaining challenges associated with this unique core–shell nanostructure and provide our perspectives on the future development of the field.
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Dinh Lam, Nguyen, Youngjo Kim, Kangho Kim i Jaejin Lee. "Influences of InGaP Conical Frustum Nanostructures on the Characteristics of GaAs Solar Cells". Journal of Nanomaterials 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/785359.
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Conical frustums with quasihexagonal nanostructures are fabricated on an InGaP window layer of single junction GaAs solar cells using a polystyrene nanosphere lithography technique followed by anisotropic etching processes. The optical and photovoltaic characteristics of the conical frustum nanostructured solar cells are investigated. Reflectance of the conical frustum nanostructured solar cells is significantly reduced in a wide range of wavelengths compared to that of the planar sample. The measured reflectance reduction is attributed to the gradual change in the refractive index of the InGaP conical frustum window layer. An increase of 15.2% in the power conversion efficiency has been achieved in the fabricated cell with an optimized conical frustum nanostructure compared to that of the planar cell.
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Richardson, David, i Fernando M. F. Rhen. "Magnetic Properties of Co-B Nanostructures Prepared via Electroless Deposition". Solid State Phenomena 233-234 (lipiec 2015): 648–52. http://dx.doi.org/10.4028/www.scientific.net/ssp.233-234.648.
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We have investigated the magnetic properties of nanostructured Co-B alloys, that were prepared via electroless deposition. The deposition process results in the formation of a nanostructure consisting of nanotubes connected to thin films at both ends. Depending on the deposition time end-open or end-closed nanotubes can be formed. The overall nanostructure of Co-B deposit has a specific magnetization of 65.6 ± 8 JT-1Kg-1 (0.75 ± 0.09 μB per Co atom). We also investigated the anisotropy of the nanostructure by carrying out magnetic measurements with and without the top and base films. We only observed magnetic anisotropy in nanostructures with thin films, which had minimum coercivities of 557 A/m (7 Oe) and 4536 A/m (57 Oe) measured parallel and perpendicular to the nanotube axis. The nanotubes do not show any significant anisotropy with coercivities of 8753 A/m (110 Oe) and 7161 A/m (90 Oe) parallel and perpendicular to the nanotube axis.
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Saranathan, Vinodkumar, Jason D. Forster, Heeso Noh, Seng-Fatt Liew, Simon G. J. Mochrie, Hui Cao, Eric R. Dufresne i Richard O. Prum. "Structure and optical function of amorphous photonic nanostructures from avian feather barbs: a comparative small angle X-ray scattering (SAXS) analysis of 230 bird species". Journal of The Royal Society Interface 9, nr 75 (9.05.2012): 2563–80. http://dx.doi.org/10.1098/rsif.2012.0191.
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Non-iridescent structural colours of feathers are a diverse and an important part of the phenotype of many birds. These colours are generally produced by three-dimensional, amorphous (or quasi-ordered) spongy β-keratin and air nanostructures found in the medullary cells of feather barbs. Two main classes of three-dimensional barb nanostructures are known, characterized by a tortuous network of air channels or a close packing of spheroidal air cavities. Using synchrotron small angle X-ray scattering (SAXS) and optical spectrophotometry, we characterized the nanostructure and optical function of 297 distinctly coloured feathers from 230 species belonging to 163 genera in 51 avian families. The SAXS data provided quantitative diagnoses of the channel- and sphere-type nanostructures, and confirmed the presence of a predominant, isotropic length scale of variation in refractive index that produces strong reinforcement of a narrow band of scattered wavelengths. The SAXS structural data identified a new class of rudimentary or weakly nanostructured feathers responsible for slate-grey, and blue-grey structural colours . SAXS structural data provided good predictions of the single-scattering peak of the optical reflectance of the feathers. The SAXS structural measurements of channel- and sphere-type nanostructures are also similar to experimental scattering data from synthetic soft matter systems that self-assemble by phase separation. These results further support the hypothesis that colour-producing protein and air nanostructures in feather barbs are probably self-assembled by arrested phase separation of polymerizing β-keratin from the cytoplasm of medullary cells. Such avian amorphous photonic nanostructures with isotropic optical properties may provide biomimetic inspiration for photonic technology.
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Silvestre, Clara. "Coordination Action: NMP3-CA-2008-218331-NaPolyNet Setting up Research-Intensive Clusters across the EU on Characterization of Polymer Nanostructures". Solid State Phenomena 151 (kwiecień 2009): 101–7. http://dx.doi.org/10.4028/www.scientific.net/ssp.151.101.
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NaPolyNet is a 36 month project involving 15 partners from 10 European countries. The objectives are: 1) to network at regional, national and international level with experts on the characterization of polymer nanostructured materials in the field of packaging, textiles and membranes, bridging the gap between scientific and engineering approaches for the improved understanding of the structure-performance correlation in polymer devices; 2) to facilitate transnational access to important and unique equipment and to train young scientists and SMEs technologists; 3) to harmonize the work necessary for new standards in the field of characterization of polymer nanostructures for packaging, textiles and membranes. NaPolyNet will also focus on latest findings for managing the safety implications of polymer nanostructure along the life-cycle of those products. The activities are grouped into 7 work-packages (WP). After setting up the procedures for managing the project, the team will map the competences in the different field of characterization of polymer nanostructures and will set up an European Open Laboratory (EOL) open to outside the consortium partners incorporating the best and novel characterization methodologies and expertises. The EOL will allow average trained users of equipment for thermal, structural, morphological, mechanical characterization to produce reliable data on nanostructured materials and correctly interpret them. An international Workshop is planned on processing-structure-dynamics-and-properties of polymer nanostructures in order to further support development and design of intrinsically safe nanomaterials. The last part of the project will be dedicated to harmonize the work for preparation of new standards for polymeric nanomaterials characterization and to overcome barriers to the industrial application of polymer nanostructured materials especially in SMEs.
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Ramadan, Rehab, i Raúl J. Martín-Palma. "The Impact of Nanostructured Silicon and Hybrid Materials on the Thermoelectric Performance of Thermoelectric Devices: Review". Energies 15, nr 15 (24.07.2022): 5363. http://dx.doi.org/10.3390/en15155363.
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Nanostructured materials remarkably improve the overall properties of thermoelectric devices, mainly due to the increase in the surface-to-volume ratio. This behavior is attributed to an increased number of scattered phonons at the interfaces and boundaries of the nanostructures. Among many other materials, nanostructured Si was used to expand the power generation compared to bulk crystalline Si, which leads to a reduction in thermal conductivity. However, the use of nanostructured Si leads to a reduction in the electrical conductivity due to the formation of low dimensional features in the heavily doped Si regions. Accordingly, the fabrication of hybrid nanostructures based on nanostructured Si and other different nanostructured materials constitutes another strategy to combine a reduction in the thermal conductivity while keeping the good electrical conduction properties. This review deals with the properties of Si-based thermoelectric devices modified by different nanostructures and hybrid nanostructured materials.
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Li, Hongdong, Shaoheng Cheng, Jia Li i Jie Song. "A Review on the Low-Dimensional and Hybridized Nanostructured Diamond Films". Journal of Nanomaterials 2015 (2015): 1–15. http://dx.doi.org/10.1155/2015/692562.
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In the last decade, besides the breakthrough of high-rate growth of chemical vapor deposited single-crystal diamonds, numerous nanostructured diamond films have been rapidly developed in the research fields of the diamond-based sciences and industrial applications. The low-dimensional diamonds of two-dimensional atomic-thick nanofilms and nanostructural diamond on the surface of bulk diamond films have been theoretically and experimentally investigated. In addition, the diamond-related hybrid nanostructures of n-type oxide/p-type diamond and n-type nitride/p-type diamond, having high performance physical and chemical properties, are proposed for further applications. In this review, we first briefly introduce the three categories of diamond nanostructures and then outline the current advances in these topics, including their design, fabrication, characterization, and properties. Finally, we address the remaining challenges in the research field and the future activities.
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Jang, Jae Min, Sung Hak Yi, Seung Kyu Choi, Jeong A. Kim i Woo Gwang Jung. "Synthesis of ZnO Flower-Like Nanostructures on GaN Epitaxial Layer by Hydrothermal Process". Solid State Phenomena 124-126 (czerwiec 2007): 555–58. http://dx.doi.org/10.4028/www.scientific.net/ssp.124-126.555.
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3D type flower-like ZnO nanostructure is fabricated on GaN epitaxial layer by hydrothermal synthesis. The formation of ZnO nanostructures is controlled dominantly by pH of the aqueous solution. The microstructure of flower-like ZnO nanostructure was examined by FE-SEM, XRD and FE-TEM. It is found that the shape of ZnO nanostructures are likely flower and chestnut bur shapes. FE-TEM and XRD analysis shows that ZnO nanostructures are single crystalline. Some discussion is made on the mechanism of ZnO growth in solutions with different pH.
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Afshar, Elham N., Georgi Xosrovashvili, Rasoul Rouhi i Nima E. Gorji. "Review on the application of nanostructure materials in solar cells". Modern Physics Letters B 29, nr 21 (10.08.2015): 1550118. http://dx.doi.org/10.1142/s0217984915501183.
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In recent years, nanostructure materials have opened a promising route to future of the renewable sources, especially in the solar cells. This paper considers the advantages of nanostructure materials in improving the performance and stability of the solar cell structures. These structures have been employed for various performance/energy conversion enhancement strategies. Here, we have investigated four types of nanostructures applied in solar cells, where all of them are named as quantum solar cells. We have also discussed recent development of quantum dot nanoparticles and carbon nanotubes enabling quantum solar cells to be competitive with the conventional solar cells. Furthermore, the advantages, disadvantages and industrializing challenges of nanostructured solar cells have been investigated.
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Verma, Sneha, i B. M. A. Rahman. "Computational Investigation of Advanced Refractive Index Sensor Using 3-Dimensional Metamaterial Based Nanoantenna Array". Sensors 23, nr 3 (23.01.2023): 1290. http://dx.doi.org/10.3390/s23031290.
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Photonic researchers are increasingly exploiting nanotechnology due to the development of numerous prevalent nanosized manufacturing technologies, which has enabled novel shape-optimized nanostructures to be manufactured and investigated. Hybrid nanostructures that integrate dielectric resonators with plasmonic nanostructures are also offering new opportunities. In this work, we have explored a hybrid coupled nano-structured antenna with stacked multilayer lithium tantalate (LiTaO3) and Aluminum oxide (Al2O3), operating at wavelength ranging from 400 nm to 2000 nm. Here, the sensitivity response has been explored of these nano-structured hybrid arrays. It shows a strong electromagnetic confinement in the separation gap (g) of the dimers due to strong surface plasmon resonance (SPR). The influences of the structural dimensions have been investigated to optimize the sensitivity. The designed hybrid coupled nanostructure with the combination of 10 layers of gold (Au) and Lithium tantalate (LiTaO3) or Aluminum oxide (Al2O3) (five layers each) having height, h1 = h2 = 10 nm exhibits 730 and 660 nm/RIU sensitivity, respectively. The sensitivity of the proposed hybrid nanostructure has been compared with a single metallic (only gold) elliptical paired nanostructure. Depending on these findings, we demonstrated that a roughly two-fold increase in the sensitivity (S) can be obtained by utilizing a hybrid coupled nanostructure compared to an identical nanostructure, which competes with traditional sensors of the same height, (h). Our innovative novel plasmonic hybrid nanostructures provide a framework for developing plasmonic nanostructures for use in various sensing applications.
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Razzaq, Abdul, i Su-Il In. "TiO2 Based Nanostructures for Photocatalytic CO2 Conversion to Valuable Chemicals". Micromachines 10, nr 5 (15.05.2019): 326. http://dx.doi.org/10.3390/mi10050326.
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Photocatalytic conversion of CO2 to useful products is an alluring approach for acquiring the two-fold benefits of normalizing excess atmospheric CO2 levels and the production of solar chemicals/fuels. Therefore, photocatalytic materials are continuously being developed with enhanced performance in accordance with their respective domains. In recent years, nanostructured photocatalysts such as one dimensional (1-D), two dimensional (2-D) and three dimensional (3-D)/hierarchical have been a subject of great importance because of their explicit advantages over 0-D photocatalysts, including high surface areas, effective charge separation, directional charge transport, and light trapping/scattering effects. Furthermore, the strategy of doping (metals and non-metals), as well as coupling with a secondary material (noble metals, another semiconductor material, graphene, etc.), of nanostructured photocatalysts has resulted in an amplified photocatalytic performance. In the present review article, various titanium dioxide (TiO2)-based nanostructured photocatalysts are briefly overviewed with respect to their application in photocatalytic CO2 conversion to value-added chemicals. This review primarily focuses on the latest developments in TiO2-based nanostructures, specifically 1-D (TiO2 nanotubes, nanorods, nanowires, nanobelts etc.) and 2-D (TiO2 nanosheets, nanolayers), and the reaction conditions and analysis of key parameters and their role in the up-grading and augmentation of photocatalytic performance. Moreover, TiO2-based 3-D and/or hierarchical nanostructures for CO2 conversions are also briefly scrutinized, as they exhibit excellent performance based on the special nanostructure framework, and can be an exemplary photocatalyst architecture demonstrating an admirable performance in the near future.
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Tahmasian, Arineh, Ali Morsali i Sang Woo Joo. "Sonochemical Syntheses of a One-Dimensional Mg(II) Metal-Organic Framework: A New Precursor for Preparation of MgO One-Dimensional Nanostructure". Journal of Nanomaterials 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/313456.
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Nanostructure of aMgIImetal-organic framework (MOF), {[Mg(HIDC)(H2O)2]·1.5H2O}n(1) (H3IDC = 4,5-imidazoledicarboxylic acid), was synthesized by a sonochemical method and characterized by scanning electron microscopy, X-ray powder diffraction, IR spectroscopy, and elemental analyses. The effect of concentration of starting reagents on size and morphology of nanostructured compound1has been studied. Calcination of the bulk powder and nanosized compound1at 650°C under air atmosphere yields MgO nanostructures. Results show that the size and morphology of the MgO nanoparticles are dependent upon the particles size of compound1.
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Bae, Eun Jeong, Dong-Hyun Baek i Young Wook Park. "Characteristics of Self-Nanostructured Growth of 4,6-Bis(3,5-di(pyridin-3-yl)phenyl)-2-Methylpyrimidine (B3PyMPM)". Journal of Nanoscience and Nanotechnology 21, nr 8 (1.08.2021): 4212–15. http://dx.doi.org/10.1166/jnn.2021.19385.
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In this study, we report the self-nanostructured growth of 4,6-bis(3,5-di(pyridin-3-yl)phenyl)-2-methylpyrimidine (B3PyMPM), which is widely used as an electron transport layer for organic light-emitting diodes (OLEDs). B3PyMPM nanostructures were formed on the surface of a substrate using vacuum thermal evaporation, and parameters such as substrate rotation speed and evaporation angle were altered to study their effect on the growth of nanostructures. Moreover, it was proven that the growth of nanostructures was dependent on the underneath materials. This self-nanostructured growth of B3PyMPM would affect the outcoupling and the efficiency improvement of OLEDs.
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Yang, Jin, Can Weng, Jun Lai, Tao Ding i Hao Wang. "Molecular Dynamics Simulation on the Influences of Nanostructure Shape, Interfacial Adhesion Energy, and Mold Insert Material on the Demolding Process of Micro-Injection Molding". Polymers 11, nr 10 (27.09.2019): 1573. http://dx.doi.org/10.3390/polym11101573.
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In micro-injection molding, the interaction between the polymer and the mold insert has an important effect on demolding quality of nanostructure. An all-atom molecular dynamics simulation method was performed to study the effect of nanostructure shape, interfacial adhesion energy, and mold insert material on demolding quality of nanostructures. The deformation behaviors of nanostructures were analyzed by calculating the non-bonded interaction energies, the density distributions, the radii of gyration, the potential energies, and the snapshots of the demolding stage. The nanostructure shape had a direct impact on demolding quality. When the contact areas were the same, the nanostructure shape did not affect the non-bonded interaction energy at PP-Ni interface. During the demolding process, the radii of gyration of molecular chains were greatly increased, and the overall density was decreased significantly. After assuming that the mold insert surface was coated with an anti-stick coating, the surface burrs, the necking, and the stretching of nanostructures were significantly reduced after demolding. The deformation of nanostructures in the Ni and Cu mold inserts were more serious than that of the Al2O3 and Si mold inserts. In general, this study would provide theoretical guidance for the design of nanostructure shape and the selection of mold insert material.
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Vikal, Sagar, Yogendra K. Gautam, Anit K. Ambedkar, Durvesh Gautam, Jyoti Singh, Dharmendra Pratap, Ashwani Kumar, Sanjay Kumar, Meenal Gupta i Beer Pal Singh. "Structural, optical and antimicrobial properties of pure and Ag-doped ZnO nanostructures". Journal of Semiconductors 43, nr 3 (1.03.2022): 032802. http://dx.doi.org/10.1088/1674-4926/43/3/032802.
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Abstract In the present work, zinc oxide (ZnO) and silver (Ag) doped ZnO nanostructures are synthesized using a hydrothermal method. Structural quality of the products is attested using X-ray diffraction, which confirms the hexagonal wurtzite structure of pure ZnO and Ag-doped ZnO nanostructures. XRD further confirms the crystallite orientation along the c-axis, (101) plane. The field emission scanning electron microscope study reveals the change in shape of the synthesized ZnO particles from hexagonal nanoparticles to needle-shaped nanostructures for 3 wt% Ag-doped ZnO. The optical band gaps and lattice strain of nanostructures is increased significantly with the increase of doping concentration of Ag in ZnO nanostructure. The antimicrobial activity of synthesized nanostructures has been evaluated against the gram-positive human pathogenic bacteria, Staphylococcus aureus via an agarose gel diffusion test. The maximum value of zone of inhibition (22 mm) is achieved for 3 wt% Ag-doped ZnO nanostructure and it clearly demonstrates the remarkable antibacterial activity.
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Singh, A., S. Bhatia i V. Rana. "Inhalable Nanostructures for Lung Cancer Treatment: Progress and Challenges". Current Nanomedicine 9, nr 1 (15.03.2019): 4–29. http://dx.doi.org/10.2174/2468187308666180307152049.
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Background: Worldwide, lung cancer is the major cause of deaths due to cancer. Most of the lung cancer cases are categorized as 85% cases of non-small cell lung cancer, while remainder 15% cases are known as small cell lung cancer. The long survival time as well as the improved quality of life for patients undergoing lung cancer using conventional chemotherapy is still not satisfactory. Therefore, robust research undergoes development of drug delivery system which increased drug at target side with reduced systemic side effect. Method: Bibliography database reviewed various inhalable nanostructured drug delivery strategies for effective delivery of anticancer drugs to lung cancer which are designed to improve the therapeutic index of anticancer drugs throughout improvement of their stability as well as bioavailability. Results: It has been reported that nanostructure based inhalation chemotherapy is more successful targeting system and also offers reduced side effects than conventional chemotherapy. Conclusion: Thus, the review highlights the critical issues, strategies for delivery and provides detail on various inhalable nanostructures for anticancer drug delivery along with toxicity concerns as well as rationale behind development of inhalable nanostructures.