Nanomaterials最新文献

Discovering stable polymeric nitrogen phases and exploring their properties are crucial for energy storage and conversion, garnering significant attention. In this study, we investigate the formation possibility of a stable compound between Ar and N₂ through ab initio calculations under low-pressure conditions (0-100 GPa). The novel super nitride, Imm2 ArN_10, is designed to demonstrate robust thermodynamic stability under high pressures (91 GPa) and showcase the unique host-guest structure, in which guest atoms (Ar) are trapped inside the host polymeric N₁₀. Significantly, given the weak interaction between Ar and N atoms and a channel parallel to the c-crystallographic axis in ArN₁₀, we propose a novel method to stabilize the previously unknown polymeric nitrogen structure, Imm2-N₁₀, by removing the guest argon atoms from the natural channels of ArN₁₀. Imm2 ArN₁₀ and N₁₀ are thermodynamically and dynamically stable, with energy densities of 9.1 kJ g^-1 and 12.3 kJ g^-1, respectively-more than twice that of TNT. Additionally, ArN₁₀ and N₁₀ stand out as leading green energetic materials, boasting a superior explosion velocity of 17.56 km s^-1 and a detonation pressure of 1712 kbar, surpassing that of TNT. These findings significantly impact on the creation of pure nitrogen frameworks through chemical reactions involving inert elements under high pressure.

The main aim of this study is probabilistic computer simulation of the effective physical parameters of fluids containing nanoparticles. A deterministic model following the rule of mixtures and some semi-empirical formulas are employed to calculate effective density, heat conductivity, heat capacity, as well as viscosity for the given nanofluid. This models is randomized here using the Monte-Carlo simulation apparatus for estimation of the Shannon entropy of all these physical parameters, which is the crucial novelty of this study. The volume fraction of the nanoparticles is assumed for this purpose as the Gaussian uncertainty source with the given first two moments. The basic probabilistic characteristics of the nanofluids' homogenized parameters have also been determined here for some validation of Shannon entropy variations in addition to the statistical disorder of the nanoparticle fraction. These research findings contribute to advancing nanofluidic and microfluidic research, offering robust tools for uncertainty analysis and enhancing the reliability of physical parameter predictions in applications requiring high numerical and/or experimental precision.

The growing demand for high-performance oxide transistors in advanced integrated circuits (ICs) underscores the need for innovative device structures, with heterojunctions emerging as a promising approach. This study presents high-performance ITO/ZnO transistors, which outperform individual ITO or ZnO transistors by achieving an on-state current of 19.2 μA/μm at a drain voltage of 1 V and exhibiting a minimal threshold voltage shift of -0.16 V under negative bias illumination stress. Band structure analysis reveals that the differences in the conduction band minimum and Fermi level between the ZnO and ITO films lead to the formation of a potential well at the ITO/ZnO interface. Furthermore, the increase in the on-state current is attributed to electron confinement at the ITO/ZnO interface, while the enhanced NBIS stability is ascribed to both the band structure and ZnO passivation. These findings make significant contributions to both optimizing the performance and analyzing the mechanisms of oxide devices, highlighting the potential of high-performance ITO/ZnO transistors in 3D integrated circuits, advanced memory devices, and back-end-of-line (BEOL) processes.

Near-infrared persistent luminescence (PersL) nanoparticles (NPs) have great potential in biomedical applications due to their ability to continuously emit tissue-penetrating light. Despite numerous reports on the distribution, biological safety and other consequences of PersL NPs in vitro and in vivo, there has been a lack of studies on the optical properties of these NPs in the physiological environment. In light of this, we investigated the effects of short-term immersion of the prominent Cr³⁺-doped ZnGa₂O₄ (CZGO) NPs in a simulated physiological environment for up to 48 h. This paper reports the changes in the structural and optical properties of CZGO NPs after their immersion in a phosphate-buffered saline (PBS) solution for pre-determined time intervals. Interestingly, the luminescence intensity and lifetime noticeably improved upon exposure to the PBS media, which is unusual among existing nanomaterials explored as bioimaging probes. After 48 h of immersion in the PBS solution, the CZGO NPs were approximately twice as bright as the non-immersed sample. X-ray spectroscopic techniques revealed the formation of ZnO, which results in an improvement in observed luminescence.

The booming expansion of nanotechnology poses the problem of environmental pollution by nanoparticles (NPs). The available methods for sensing and removing NPs from the environment are typically lengthy and instrumentally demanding. The recent introduction of NP-imprinted polymers (NPIPs), either as films or bulk materials, is an important step toward the simple and fast sensing and removal of NPs from water and air. Similarly to the well-established molecularly imprinted polymers, in NPIPs, an organic or inorganic polymeric material is first obtained with embedded NPs. Then, the NPs are chemically or physically removed by acting as a template, i.e., leaving a polymeric matrix with cavities of the same shape and dimensions. After the first examples were published in 2014, the literature has so far reported an increasing number of NPIPs that are capable of reuptaking NPs from water (or, more rarely, air), with remarkable size and shape selectivity. By laying an NPIP layer on a reporter (typically an electrode), devices are obtained that are capable of sensing NPs. On the other hand, bulk NPIPs can reuptake massive amounts of NPs and have been used for the quantitative removal of NPs from water. This review begins with an overview of NP-imprinted hollow capsules, which can be considered the ancestors of NPIPs, both as conception and as preparative methods. Then, the literature on NPIPs is reviewed. Finally, the possible evolutions of NPIPs are highlighted from the perspective of stepping toward their real-life, field use.

Acute myocardial infarction is an ischemic injury of the myocardium caused by an imbalance in the blood supply to myocardial tissues, which poses a serious threat to human life and health. Oxidative stress has been recognized as a significant contributor to acute myocardial infarction. Salvia miltiorrhiza Carbonisata (SMC) is among the most frequently employed herbal remedies for the treatment of acute myocardial infarction; however, the exact identity of its principal active constituents is not well defined. Research indicates that carbon dots (CDs) exhibit significant biological properties. Consequently, we initially synthesized carbon dots (CDs) from Salvia miltiorrhiza Carbonisata, with the objective of exploring how SMC-CDs mitigate isoproterenol (ISO)-induced myocardial infarction (MI) in rats. The results showed that the pretreatment with SMC-CDs markedly enhanced compromised cardiac function, mitigated myocardial fibrosis and the infiltration of inflammatory cells, decreased the size of the infarct, and suppressed cardiomyocyte apoptosis. Furthermore, the antioxidant properties of myocardial tissue were enhanced, and oxidative stress caused by free radicals was effectively mitigated by SMC-CDs, which succeeded in reducing levels of myocardial enzymes and elevating the activity of relevant ATPases. This implies that SMC-CDs could be a potential candidate for novel nanomedicine strategies designed to address cardiovascular ailments.

Energy issues, including energy generation, conversion, transmission and detection, are fundamental factors in all systems. In micro- and nanosystems, dealing with these energy issues requires novel nanostructures and precise technology. However, both concept and setup are not well established yet in the microsystems, especially for those at the nanometer scale. Here, we demonstrate electromagnetic nanocoils with 100 nm diameters based on uniform and periodic InGaN nanoring arrays grown on patterned GaN surfaces using nanoscale selective area epitaxy (NSAE). We observed stronger photoluminescence from the periodic InGaN nanoring arrays compared to the non-uniform InGaN nanorings, which indicates good crystal quality of the InGaN nanostructure with the NSAE. Based on this kind of nanostructure, electromagnetic induction from the nanorings is detected through the rebound movement of high-energy electron diffraction patterns that are influenced by a modulated external magnetic field. Our results clearly show the generation of an inductive current and internal magnetic field in the nanorings. We anticipate this kind of nanostructure to be a potential key element for energy conversion, transfer and detection in nanosystems. For example, it could be used to fabricate microtransformers and micro- and nanosensors for electromagnetic signals.

The half-Heusler semiconductors ZrNiPb and ZrPdPb have attracted considerable attention due to their excellent thermoelectric performance, owing largely to their appropriate energy bandgap. However, the bandgap is sensitive to pressure, which may influence their thermoelectric behavior. In this study, the effects of pressure on the elastic, electronic, and thermodynamic properties of the half-Heusler semiconductors ZrNiPb and ZrPdPb are investigated based on first-principles calculations combined with the quasi-harmonic Debye model. After verifying their structural, dynamic, and mechanical stability, we found a small indirect bandgap of 0.36 eV for ZrNiPb and 0.49 eV for ZrPdPb, and they increase with increasing pressure. According to the obtained elastic modulus, ZrNiPb and ZrPdPb become more and more ductile as the pressure increases. In addition, the thermodynamic properties of ZrNiPb and ZrPdPb are investigated using the quasi-harmonic Debye model, as implemented in the Gibbs program, which will provide a reference for the experiment.

Rapid thermal annealing (RTA) has been widely used in semiconductor device processing. However, the rise time of RTA, limited to the millisecond (ms) range, is unsuitable for advanced nanometer-scale electronic devices. Using sub-energy bandgap (E_G) 532 nm ultra-fast 15 nanosecond (ns) pulsed laser annealing, a record-high dielectric constant (high-κ) of 67.8 and a capacitance density of 75 fF/μm² at -0.2 V were achieved in Ni/ZrO₂/TiN capacitors. According to heat source and diffusion equations, the surface temperature of TiN can reach as high as 870 °C at a laser energy density of 16.2 J/cm², effectively annealing the ZrO₂ material. These record-breaking results are enabled by a novel annealing method-the surface plasma effect generated on the TiN metal. This is because the 2.3 eV (532 nm) pulsed laser energy is significantly lower than the 5.0-5.8 eV energy bandgap (E_G) of ZrO₂, making it unabsorbable by the ZrO₂ dielectric. X-ray diffraction analysis reveals that the large κ value and capacitance density are attributed to the enhanced crystallinity of the cubic-phase ZrO₂, which is improved through laser annealing. This advancement is critical for monolithic three-dimensional device integration in the backend of advanced integrated circuits.

In this paper, we investigate the effect of singular viscosity on the stability of a thin film of Oldroyd-B viscoelastic fluid flowing along a porous inclined surface under the influence of a normal electric field. First, we derive the governing equations and boundary conditions for the flow of the film and assume that the film satisfies the Beavers-Joseph sliding boundary condition when it flows on a porous inclined surface. Second, through the long-wave approximation, we derive the nonlinear interfacial evolution equation. Then, linear and nonlinear stability analyses are performed for the interfacial evolution equation. The stability analyses show that the singular viscosity has a stabilizing effect on the flow of the film, while the strain delay time of the Oldroyd-B fluid, the electric field, and the parameters of the porous medium all have an unsteady effect on the flow of the film. Interestingly, in the linear stability analysis, the parameters of the porous medium have an unsteady effect on the flow of the film after a certain value is reached and a stabilizing effect before that value is reached. In order to verify these results, we performed numerical simulations of the nonlinear evolution equations using the Fourier spectral method, and the conclusions obtained are in agreement with the results of the linear stability analysis, i.e., the amplitude of the free surface decreases progressively with time in the stable region, whereas it increases progressively with time in the unstable region.