Characterization of a Robust CoII Fluorescent Complex Deposited Intact On HOPG

The new diimine fluorescent ligand ACRI‐1 based on a central acridine yellow core is reported along with its coordination complex [Co₂( ACRI‐1 )₂] ( 1 ), a fluorescent weak ferromagnet. Due to the strong fluorescence of the acridine yellow fluorophore, it is not completely quenched when the ligand is coordinated to Co^II. The magnetic properties of bulk complex 1 and its stability in solution have been studied. Complex 1 has been deposited on highly ordered pyrolitic graphite (HOGP) from solution. The thin films prepared have been characterized by AFM, time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS), grazing incidence X‐ray diffraction (GIXRD), X‐ray absorption spectroscopy (XAS), X‐ray magnetic circular dichroism (XMCD) and theoretical calculations. The data show that the complex is robust and remains intact on the surface of graphite.     

A review on sources,toxicity and remediation technologies for removing arsenic from drinking water

Arsenic is a natural element found in the environment in organic and inorganic forms. The inorganic form is much more toxic and is found in ground water, surface water and many foods. This form is responsible for many adverse health effects like cancer (skin, lung, liver, kidney and bladder mainly), and cardiovascular and neurological effects. The estimated number of people in Bangladesh in 1998 exposed to arsenic concentrations above 0.05 mg/l is 28–35 million, and the number of those exposed to more than 0.01 mg/l is 46–57 million. The estimated number of people in West Bengal, India (the border province to Bangladesh), in 1997 actually using arsenic-rich water is more than 1 million for concentrations above 0.05 mg/l and is 1.3 million for concentrations above 0.01 mg/l. The United States Environmental Protection Agency (USEPA) has estimated that 13 million of the US population are exposed to arsenic in drinking water at 0.01 mg/l. The situation has prevailed for more than 10 years and is more severe now. The USEPA lowered the maximum contaminant level (MCL) for drinking water arsenic from 50 to 10 μg/l in 2001 based on international data analysis and research. This recommendation is now on hold. The level of 10 ppb become standard in the European Union (EU) in 2001. Arsenic may be found in water flowing through arsenic-rich rocks. The source is diverse. These include the earth's crust, introduced into water through the dissociation of minerals and ores, industrial effluents to water, combustion of fossil fuels and seafoods. Arsenic-removal methods are coagulation (ferric sulfate, ferrous sulfate, ferric chloride, aluminum sulfate, copper sulfate, and calcium hydroxide as coagulants), adsorption (activated carbon, activated alumina, activated bauxite) ion exchange, bio-sorption, etc.     

Shannon entropy as a predictor of avoided crossing in confined atoms

Avoided crossing is one of the unique spectroscopic features of a confined atomic system. Shannon information entropy of the ground state and some of the excited states of confined H atom as a predictor of avoided crossing is studied in this work. This is accomplished by varying the strength of the confinement and examining structure properties like ionization energy and Shannon information entropy. Along with the energy level repulsion at the avoided crossing, Shannon information entropy is also exchanged between the involved states. This work also addresses a question: In addition to that regarding localization, what other property of the system can be extracted from Shannon entropy? Insightful connection is discovered between Shannon entropy and the average value of confinement potential, Coulomb potential, and kinetic energy.     

Heterometallic Triply‐Bridging Bis‐Borylene Complexes

Triply‐bridging bis‐{hydrido(borylene)} and bis‐borylene species of groups 6, 8 and 9 transition metals are reported. Mild thermolysis of [Fe₂(CO)₉] with an in situ produced intermediate, generated from the low‐temperature reaction of [Cp*WCl₄] (Cp*=η⁵‐C₅Me₅) and [LiBH₄?THF] afforded triply‐bridging bis‐{hydrido(borylene)}, [(μ₃‐BH)₂H₂{Cp*W(CO)₂}₂{Fe(CO)₂}] ( 1 ) and bis‐borylene, [(μ₃‐BH)₂{Cp*W(CO)₂}₂{Fe(CO)₃}] ( 2 ). The chemical bonding analyses of 1 show that the B?H interactions in bis‐{hydrido (borylene)} species is stronger as compared to the M?H ones. Frontier molecular orbital analysis shows a significantly larger energy gap between the HOMO‐LUMO for 2 as compared to 1 . In an attempt to synthesize the ruthenium analogue of 1 , a similar reaction has been performed with [Ru₃(CO)₁₂]. Although we failed to get the bis‐{hydrido(borylene)} species, the reaction afforded triply‐bridging bis‐borylene species [(μ₃‐BH)₂{WCp*(CO)₂}₂{Ru(CO)₃}] ( 2′ ), an analogue of 2 . In search for the isolation of bridging bis‐borylene species of Rh, we have treated [Co₂(CO)₈] with nido‐[(RhCp*)₂(B₃H₇)], which afforded triply‐bridging bis‐borylene species [(μ₃‐BH)₂(RhCp*)₂Co₂(CO)₄(μ‐CO)] ( 3 ). All the compounds have been characterized by means of single‐crystal X‐ray diffraction study; ¹H, ¹¹B, ¹³C NMR spectroscopy; IR spectroscopy and mass spectrometry.     

Unusual Surface Latent Heat Flux Variations and Their Critical Dynamics Revealed before Strong Earthquakes

We focus on the possible thermal channel of the well-known Lithosphere–Atmosphere–Ionosphere Coupling (LAIC) mechanism to identify the behavior of thermal anomalies during and prior to strong seismic events. For this, we investigate the variation of Surface Latent Heat Flux (SLHF) as resulting from satellite observables. We demonstrate a spatio-temporal variation in the SLHF before and after a set of strong seismic events occurred in Kathmandu, Nepal, and Kumamoto, Japan, having magnitudes of 7.8, 7.3, and 7.0, respectively. Before the studied earthquake cases, significant enhancements in the SLHF were identified near the epicenters. Additionally, in order to check whether critical dynamics, as the signature of a complex phenomenon such as earthquake preparation, are reflected in the SLHF data, we performed a criticality analysis using the natural time analysis method. The approach to criticality was detected within one week before each mainshock.     

Superperiodicity,chaos and coexisting orbits of ion-acoustic waves in a four-component nonextensive plasma

Superperiodicity, chaos and coexisting orbits of ion-acoustic waves (IAWs) are studied in a multi-component plasma consisting of fluid ions, q -nonextensive cold and hot electrons and Maxwellian hot positrons. The significant impacts of the system parameters on superperiodic and nonlinear periodic IAWs are presented. Considering an external periodic perturbation various types of quasiperiodic and chaotic features for IAWs are studied in different parametric ranges through time series’ plots, phase spaces and Lyapunov exponents. It has been observed that there exist some coexisting orbits for IAWs. Coexisting orbits for IAWs in a classical electron–positron–ion plasma system are reported.     

Advantage of Quantum Theory over Nonclassical Models of Communication

Quantum correlations provide dramatic advantage over the corresponding classical resources in several communication tasks. However, a broad class of probabilistic theories exists that attributes greater success than quantum theory in many of these tasks by allowing supra-quantum correlations in “space-like” and/or “time-like” paradigms. In this letter, a communication task involving three spatially separated parties is proposed where one party (verifier) aims to verify whether the bit strings possessed by the other two parties (terminals) are equal or not. This task is called authentication with limited communication, the restrictions on communication being: i) the terminals cannot communicate with each other, but (ii) each of them can communicate with the verifier through single use of channels with limited capacity. Manifestly, classical resources are not sufficient for perfect success of this task. Moreover, it is also not possible to perform this task with certainty in several nonclassical theories although they might possess stronger “space-like” and/or “time-like” correlations. Surprisingly, quantum resources can achieve the perfect winning strategy. The proposed task thus stands apart from all previously known communication tasks as it exhibits quantum advantage over other nonclassical strategies.     

A terahertz polarization insensitive dual band metamaterial absorber

Metamaterial absorbers have attracted considerable attention for applications in the terahertz range. In this Letter, we report the design, fabrication, and characterization of a terahertz dual band metamaterial absorber that shows two distinct absorption peaks with high absorption. By manipulating the periodic patterned structures as well as the dielectric layer thickness of the metal-dielectric-metal structure, significantly high absorption can be obtained at specific resonance frequencies. Finite-difference time-domain modeling is used to design the structure of the absorber. The fabricated devices have been characterized using a Fourier transform IR spectrometer. The experimental results show two distinct absorption peaks at 2.7 and 5.2?THz, which are in good agreement with the simulation. The absorption magnitudes at 2.7 and 5.2?THz are 0.68 and 0.74, respectively.