Unoccupied electronic states of icosahedral Al-Pd-Mn quasicrystals: Evidence of image potential resonance and pseudogap

We study the unoccupied region of the electronic structure of the fivefold symmetric surface of an icosahedral (i) Al-Pd-Mn quasicrystal. A feature that exhibits parabolic dispersion with an effective mass of (1.15±0.1)me and tracks the change in the work function is assigned to an image potential resonance because our density functional calculation shows an absence of band gap in the respective energy region. We show that Sn grows pseudomorphically on i−Al−Pd−Mn as predicted by density functional theory calculations, and the energy of the image potential resonance tracks the change in the work function with Sn coverage. The image potential resonance appears much weaker in the spectrum from the related crystalline Al-Pd-Mn surface, demonstrating that its strength is related to the compatibility of the quasiperiodic wave functions in i−Al−Pd−Mn with the free-electron-like image potential states. Our investigation of the energy region immediately above EF provides unambiguous evidence for the presence of a pseudogap, in agreement with our density functional theory calculations

Unoccupied electronic states of icosahedral Al-Pd-Mn quasicrystals: Evidence of image potential resonance and pseudogap

We study the unoccupied region of the electronic structure of the fivefold symmetric surface of an icosahedral (i) Al-Pd-Mn quasicrystal. A feature that exhibits parabolic dispersion with an effective mass of (1.15±0.1)me and tracks the change in the work function is assigned to an image potential resonance because our density functional calculation shows an absence of band gap in the respective energy region. We show that Sn grows pseudomorphically on i−Al−Pd−Mn as predicted by density functional theory calculations, and the energy of the image potential resonance tracks the change in the work function with Sn coverage. The image potential resonance appears much weaker in the spectrum from the related crystalline Al-Pd-Mn surface, demonstrating that its strength is related to the compatibility of the quasiperiodic wave functions in i−Al−Pd−Mn with the free-electron-like image potential states. Our investigation of the energy region immediately above EF provides unambiguous evidence for the presence of a pseudogap, in agreement with our density functional theory calculations

A case study for the formation of stanene on a metal surface

The discovery and realization of graphene as an ideal two-dimensional (2D) material has triggered extensive efforts to create similar 2D materials with exciting spin-dependent properties. Here, we report on a novel Sn 2D superstructure on Au(111) that shows similarities and differences to the expected electronic features of ideal stanene. Using spin- and angle-resolved photoemission spectroscopy, we find that a particular Sn/Au superstructure reveals a linearly dispersing band centered at the Γ-point and below the Fermi level with antiparallel spin polarization and a Fermi velocity of vF ≈ 1×106 m/s, the same value as for graphene. We attribute the origin of the band structure to the hybridization between the Sn and the Au orbitals at the 2D Sn-Au interface. Considering that free-standing stanene simply cannot exist, our investigated structure is an important step towards the search of useful stanene-like overstructures for future technological applications

Optimization and characterization of green synthesized silver nanoparticles and its inhibitory activity against biofilm forming bacterial pathogens

In the present study, antibacterial activity of silver nanoparticles synthesized from entophytic fungi extracts were analysed against biofilm forming bacteria include the Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa isolated from clinical specimens. Therefore, we tried to establish a combination of medicinal and nanotechnology possibly with the field of medicine for the development of antibacterial agents against these strains. The nanoparticles were characterized by UV–visible spectroscopy, the presented and capped molecules of proteins with nanoparticles was confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD). UV–visible studies display an absorption band at 420 nm due to surface Plasmon resonance (SPR) of the silver nanoparticles. The intra cellular synthesized silver nanoparticles (Ag NPs) size 15-35 nm was determination of X-ray diffraction (XRD) crystal calculation, antimicrobial activity higher than the standard antibiotic. The nanoparticle treated with isolated bacteria as result macromolecule of proteins denatures and oozing out the cells and measure the Bradford method. The nanoparticle treated bacterial cells were compared to negative control more amount of protein released. The nano size establishing the silver nanoparticles directly bind with DNA of the pathogenic bacterial strains most important to higher antimicrobial activity

Nodemcu based smart home automation system using sinricpro technology

A smart home is a convenient house setting in which appliances and devices may be managed remotely using a mobile or other networked device from anywhere with an internet connection. A smart home's devices are connected via the internet, allowing the user to handle features such as home security, temperature, lighting, and a home theatre from afar. Now we'll focus on the most frequent question on whether this smart home automation is much more efficient compared to the traditional household activity. The answer is yes because Smart homes provide you more control over your energy consumption by automating things like temperature management and light switching and give you information on how you use energy, which can help you become more energy efficient and environmentally conscious. This also will be very beneficial for old and handicap people since they have difficulties in controlling home appliances where in the presences of automation system, they do to have to exert themselves. A smart home automation prototype has been proposed to carry out similar activities which will be able to ease our daily lives. The proposed project aims to control home appliances, monitor motion and temperature. As a microprocessor, the NodeMCU ESP8266 module will be used to gather information wirelessly. Prototyping techniques will also be used in the development of this project. The user will be asked to login into the system using SinricPro application and then will be able to see several switches and options on monitoring the stated factors. The real-time output will be displayed, and the values will be shown in the form of graph

Bulk electronic structure of Zn-Mg-Y and Zn-Mg-Dy icosahedral quasicrystals

We use bulk sensitive hard x-ray photoelectron spectroscopy to provide unambiguous evidence for a pseudogap in the density of states around the Fermi level in icosahedral Zn-Mg-Y and Zn-Mg-Dy quasicrystals, in agreement with our density functional theory calculations. The pseudogap in these Zn-based quasicrystals is less pronounced compared to the Al-based ones such as Al-Pd-Mn and Al-Cu-Fe [J. Nayak et al., Phys. Rev. Lett. 109, 216403 (2012)]. This observation is in agreement with transport studies that indicate a larger charge carrier concentration in the Zn-based quasicrystals. Compared to Zn-Mg-Dy, the pseudogap is somewhat deeper in Zn-Mg-Y. The larger width of the Mg 1s and Zn 2p core-level spectra in Zn-Mg-Y is explained by different configurations of the local atomic surrounding compared to Zn-Mg-Dy

Enhancing performance of Prosopis juliflora fiber reinforced epoxy composites with silane treatment and Syzygium cumini filler

The utilization of natural fibers and fillers in composite materials has gained significant attention for their potential to enhance mechanical, thermal, and tribological properties while promoting sustainability. In this study, Prosopis juliflora fiber (PJF) reinforced epoxy composites, treated with silane and incorporating Syzygium cumini filler (SCF), were investigated to assess their performance across various parameters. The composites were subjected to comprehensive mechanical, tribological, thermo-gravimetric, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), 3D profilometer, and morphology studies to elucidate the effects of silane treatment and SCF content on composite properties. The results of the mechanical characterization revealed significant improvements in tensile strength, impact strength, and microhardness in silane-treated composites with higher SCF content compared to untreated samples and those with lower SCF content. Specifically, the ST/SCF3 composite exhibited the highest values, with a tensile strength of 118.65 ± 4.63 MPa, impact strength of 27.83 ± 1.96 kJ/m2, and microhardness of 91.63 ± 2.84 HV. Tribological analysis indicated enhanced wear resistance and reduced coefficient of friction in silane-treated composites with higher SCF content, with the ST/SCF3 composite demonstrating the lowest wear loss (62 μm) and frictional force (5.2 N). Thermal characterization revealed improved thermal stability in silane-treated composites, particularly in the ST/SCF1 and ST/SCF3 formulations, suggesting increased resistance to temperature-induced degradation