A free space frequency‐time‐domain technique for electromagnetic characterization of materials using reflection‐based measurement

In this report, a free space frequency‐time‐domain technique is presented for characterizing the electrical properties and thickness of the sample using multiple reflections and fabry‐perot resonance phenomenon. The retrieval of constitutive electromagnetic parameters of the sample has been carried out by comparing the measured reflection coefficient data from the sample at two different incident angles. The relative permittivity as well as relative permeability along with the thickness of different samples viz., beryllia, silicon, and plexiglass have been evaluated with high accuracy in the frequency range 1 to 15 GHz. The method is also experimentally validated by successfully reconstructing the unknown material properties of two different samples. The unique advantage of this method lies in non‐requirement of any prior knowledge of the sample's thickness for measuring the complex relative dielectric constant as well as relative permeability of the sample. To determine the electromagnetic properties of the sample, the sole knowledge of reflection coefficient data are needed. Moreover, the method does not involve any additional measurement for the reference calibration. The simple, cost‐effective proposed scheme is quite useful in many applications like accurate determination of signal strength in indoor wireless communication, through wall imaging, food industry, and so on.     

Self-assembly through hydrogen-bonding and C–Hπ interactions in metal complexes of N-functionalised glycine

The complex [Ni(L1)₂(py)₂]. toluene (L1 is N-phthaloylglycinato and py is pyridine) was prepared from solid state reaction whereas co-crystals having composition 2[Ni(L1)₂(py)₃(H₂O)] · [Ni(L1)₂(py)₂(H₂O)₂] · 2py · 2H₂O was obtained from solution state reaction.     

Investigation of Oxygen-Adsorbed Iron Pnictide Crystals

In this present study, we synthesized a new compound of YbFe₂As₂ crystals by using a melt growth technique. The YbFe₂As₂ crystals had been characterized by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX). The presence of oxygen was found by EDAX on the surfaces of grown YbFe₂As₂ crystals which had been kept in air ambience for few months. The measurement of magnetization (M) versus temperature (T) using a superconducting quantum interference device (SQUID) at constant magnetic field (H = 100 Oe) for oxygen-adsorbed YbFe₂As₂ (YbFe₂As₂:O₂) had revealed an occurrence of sharp slope change around 140 K. An additional slope change had been observed around 40 K. We had carried out magnetization and transport measurements for oxygen-adsorbed YbFe₂As₂ (YbFe₂As₂:O₂) and oxygen-adsorbed BaFe₂As₂ (BaFe₂As₂:O₂) for comparative study also. M versus T data at H = 10,000 Oe had exhibited a paramagnetic behavior for both YbFe₂As₂:O₂ and BaFe₂As₂:O₂. The result of M versus H measurements at 2 K had shown that the saturation had not been achieved for YbFe₂As₂:O₂ at H = 80,000 Oe. There was a slope change observed in transport measurement for YbFe₂As₂:O₂ at 15 K which was not noticed for BaFe₂As₂:O₂.     

Generative model based robotic grasp pose prediction with limited dataset

Applied Intelligence - In the present investigation, we propose an architecture which we name as Generative Inception Neural Network (GI-NNet), capable of predicting antipodal robotic grasps...     

A metasurface‐based broadband quasi nondispersive cross polarization converter for far infrared region

A broadband nondispersive cross polarization converter (CPC) structure using metasurface for far infrared region has been proposed in this article. The structure is transmittive in nature, which converts a linearly polarized incident wave to its mutually orthogonal linearly polarized wave over a band of frequency ranging from 10.25 to 22.7 THz maintaining a high polarization conversion ratio (PCR) of more than 0.95. The fractional bandwidth of 75.6% corresponding to the center frequency of PCR bandwidth having more than 0.9 PCR value has been realized. The structure is also studied for oblique incidences where it shows wide band polarization conversion up to 45° for both TE and TM polarized oblique incident waves. The electric field distributions at the top and bottom surfaces of the structure close to the center frequency of polarization conversion bandwidth indicate the orthogonal rotation of incident linearly polarized wave at the frequency of interest. For the given set of media interface a separate study on polarization conversion through Brewster angle concept has been carried out simultaneously. The structure exhibits high PCR by maintaining the compactness in thickness (~ λ/5) as well as periodicity (~ λ/3) compared to the existing reported ones.     

Damaged DNA Binding Protein 2 in Reactive Oxygen Species (ROS) Regulation and Premature Senescence

Premature senescence induced by DNA damage or oncogene is a critical mechanism of tumor suppression. Reactive oxygen species (ROS) have been implicated in the induction of premature senescence response. Several pathological disorders such as cancer, aging and age related neurological abnormalities have been linked to ROS deregulation. Here, we discuss how Damaged DNA binding Protein-2 (DDB2), a nucleotide excision repair protein, plays an important role in ROS regulation by epigenetically repressing the antioxidant genes MnSOD and Catalase. We further revisit a model in which DDB2 plays an instrumental role in DNA damage induced ROS accumulation, ROS induced premature senescence and inhibition of skin tumorigenesis.     

A Copper Silicide Nanofoam Current Collector for Directly Grown Si Nanowire Networks and their Application as Lithium‐Ion Anodes

Silicon nanowires (Si NWs) have been identified as an excellent candidate material for the replacement of graphite in anodes, allowing for a significant boost in the capacity of lithium‐ion batteries (LIBs). Herein, high‐density Si NWs are grown on a novel 3D interconnected network of binary‐phase Cu‐silicide nanofoam (3D Cu_xSi_y NF) substrate. The nanofoam facilitates the uniform distribution of well‐segregated and small‐sized catalyst seeds, leading to high‐density/single‐phase Si NW growth with an areal‐loading in excess of 1.0 mg cm^?2 and a stable areal capacity of ≈2.0 mAh cm^?2 after 550 cycles. The use of the 3D Cu_xSi_y NF as a substrate is further extended for Al, Bi, Cu, In, Mn, Ni, Sb, Sn, and Zn mediated Si NW growth, demonstrating the general applicability of the anode architecture.     

Stimuli-responsive Supra-biomolecular Nanoassemblies of Cucurbit[7]uril with Bovine Serum Albumin: Drug Delivery and Sensor Applications

Construction and characterization of stimuli-responsive supra-biomolecular nanoassembly between cucurbit[7]uril (CB7) and bovine serum albumin (BSA), uptake and release of doxorubicin (DOX) in live cells, the enhanced sensitivity of brilliant green (BG) and the metal ion-induced relocation of neutral red (NR) dye to BSA have been discussed in this review. The fluorescence intensity of DOX is largely quenched in the presence of nanoassembly which recovers with adamantylamine or by changing the pH of the solution, indicating the significant uptake and release of DOX. Whereas, the interaction of BG with CB7-BSA assembly leads to a huge fluorescence enhancement ∼350-fold through ternary complex formation. In another study, the supramolecular pK_a tuning of nanoassembly encapsulated NR dye with metal ion and the consequent relocation of NR from CB7 cavity to the hydrophobic pocket of BSA have been demonstrated. All these studies show promising applications in drug delivery and on-off sensor.     

Heisenberg-Like Critical Properties and Magnetocaloric Effect in Lead Doped NdMnO3 Single Crystal

Static magnetization for single crystals of Nd_0.7Pb_0.3MnO₃ has been studied around the ferromagnetic-to-paramagnetic transition temperature T _C . The results of measurements carried out in the critical range |(T?T _C )/T _C |≤0.1 are reported. The critical exponents β and γ for the thermal behavior of magnetization and susceptibility have been obtained both from the modified Arrott plots and the Kouvel–Fisher method. The exponent δ, independently obtained from the critical isotherm, was found to satisfy the Widom scaling relation δ=γ/β+1. The values of exponents are consistent with those expected for isotropic magnets belonging to the Heisenberg universality class with short-range exchange in three dimensions. The maximum magnetic entropy change is found at around T _C . We found a universal scaling behavior in the relative change of magnetic entropy (ΔS _M ). The rescaled curves of the magnetic entropy change for different applied fields are observed to collapse onto a single curve, which validates the second order nature of the phase transition in Nd_0.7Pb_0.3MnO₃.