Topochemical Path in High Lithiation of MoS2

Lithiation of MoS₂/RGO (reduced graphite oxide) electrodes repeatedly reached experimental capacities larger than 1000 mA · g^–1, corresponding to at least 6 lithium equivalents per gram of MoS₂. At our best knowledge, a convincing explanation is still missing in literature. In most cases, phase separation into Li₂S and elemental Mo was assumed to occur. However, this can only explain capacities up to 669 mA · g^–1, corresponding to an exchange of four Li. Formation of LiMo alloys could resolve the problem but the Li/Mo system does not contain any binary phases. If signs for Li₂S formation were found, indeed experimental capacities were below 700 mAh · g^–1. Here we present a topochemical mechanism, which sustains multiple charge/discharge cycles at 1000 mAh · g^–1, corresponding to an exchange of at least 6 Li per formula unit MoS₂. This topochemical reaction route prevents decomposition into binary phases and thus avoids segregation of the components of MoS₂. Throughout the whole lithiation/delithiation process, distinct layers of Mo are preserved but extended or shrunk by slight movements and reshuffling of sulfur and lithium atoms. On addition of 6 Li per formula unit to MoS₂, all central sulfur atoms are hosted in mutual Mo–S layers such that formal S^2– and Mo^2– anions appear coordinated by lithium cations. Indeed, similar structures are known in the field of Zintl phases. Our first‐principles crystal structure prediction study describes this topological path through conversion reactions during the lithiation/delithiation processes. All optimized phases along the topological path exhibit a distinct Mo layering giving rise to a series of dominant scattering into pseudo 001 reflections perpendicular to these Mo planes. The mechanism we present here explains why such high capacities can be reached reversibly for MoS₂/RGO nano composites     

Novel coordination compounds: Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) cations with acesulfame/N,N-diethylnicotinamide ligands

Abstract

Five coordination complexes with Mn²⁺ (1), Co²⁺ (2), Ni²⁺ (3), Cu²⁺ (4), and Zn²⁺ (5) containing acesulfame (ace) and N,N-diethylnicotinamide (dena) ligands were synthesized and structural binding properties investigated. Four compounds (1, 2, 4, and 5) were examined with single crystal X-ray diffraction methods. The structures containing Mn(II), Co(II), and Zn(II) were iso-structural. Six-coordination of metal cations were completed with two moles dena and four aqua ligands. The dena ligands were coordinated via pyridine nitrogen as neutral-monodentate. Charge stabilities of the complexes are complemented by two moles monoanionic ace ligands, located outside of the coordination unit. In the Cu(II) complex, the coordination is completed by acidic nitrogen and carbonyl oxygen atoms of two ace ligands and pyridine nitrogen of two moles dena ligands. The coordination to Cu(II) for ace ligands was monoanionic-bidentate. All metal cations in the structure are distorted octahedral. Thermal decomposition of complexes begins with removal of the aqua molecules from the structures and is completed by combustion of organic ligands. The final decomposition products of all structures have been identified as corresponding metal oxides. Some biological applications (anti-fungal/anti-bacterial) were studied using 1–5.     

Measurement of relative L X-ray intensity ratio following radioactive decay and photoionization

The measurements of the L   X-ray intensity ratio I(Lα)/I(Lβ)$I(L\alpha )/I(L\beta )$, I(Lα)/I(Lγ)$I(L\alpha )/I(L\gamma )$, I(Lα)/I(Lι)$I(L\alpha )/I(L\iota )$, I(Lβ)/I(Lγ)$I(L\beta )/I(L\gamma )$ and I(Lι)/I(Lγ)$I(L\iota )/I(L\gamma )$ for elements Dy, Ho, Yb, W, Hg, Tl and Pb were experimentally determined both by photon excitation, in which 59.5 keV γ-rays from a filtered radioisotope ²⁴¹Am was used, and by the radioactive decay of ¹⁶⁰Tb, ¹⁶⁰Er, ¹⁷³Lu, ¹⁸²Re, ²⁰¹Tl, ²⁰³Pb and ²⁰⁷Bi. L   X-rays emitted by samples were counted by a Si(Li) detector with resolution 160 eV at 5.9 keV. Obtained values were compared with the calculated theoretical values. Theoretical values of the I(Lα/Lβ)$I(L\alpha /L\beta )$, I(Lα/Lγ)$I(L\alpha /L\gamma )$, I(Lα/Lι)$I(L\alpha /L\iota )$, I(Lβ/Lγ)$I(L\beta /L\gamma )$ and I(Lι/Lγ)$I(L\iota /L\gamma )$ intensity ratios were calculated using theoretically tabulated values of subshell photoionization cross-section, fluorescence yield, fractional X-ray emission rates, Coster–Kronig transition probabilities. It was observed that present values agree with previous theoretical and other available experimental results.     

Chaotic inflation,radiative corrections and precision cosmology

We employ chaotic (?²${?}^2$ and ?⁴${?}^4$) inflation to illustrate the important role radiative corrections can play during the inflationary phase. Yukawa interactions of ?  , in particular, lead to corrections of the form −κ?⁴ln(?/μ)$-\kappa {?}^4\ln (?/\mu )$, where κ>0$\kappa >0$ and μ   is a renormalization scale. For instance, ?⁴${?}^4$ chaotic inflation with radiative corrections looks compatible with the most recent WMAP (5 year) analysis, in sharp contrast to the tree level case. We obtain the 95% confidence limits 2.4×¹⁰⁻¹⁴?κ?5.7×¹⁰⁻¹⁴$2.4\times {10}^{\mathrm{-14}}?\kappa ?5.7\times {10}^{\mathrm{-14}}$, 0.931?ns?0.958$0.931?n_s?0.958$ and 0.038?r?0.205$0.038?r?0.205$, where ns$n_s$ and r   respectively denote the scalar spectral index and scalar to tensor ratio. The limits for ?²${?}^2$ inflation are κ?7.7×¹⁰⁻¹⁵$\kappa ?7.7\times {10}^{\mathrm{-15}}$, 0.929?ns?0.966$0.929?n_s?0.966$ and 0.023?r?0.135$0.023?r?0.135$. The next round of precision experiments should provide a more stringent test of realistic chaotic ?²${?}^2$ and ?⁴${?}^4$ inflation.     

Ink‐Jet Printing of Electron Donor/Acceptor Blends: Towards Bulk Heterojunction Solar Cells

Summary: We illustrate the ink‐jet printing of a thin‐film library of donor/acceptor systems useful in bulk heterojunction solar cells and their characterization utilizing a UV‐vis/fluorescence plate reader and an optical profilometer. In addition, the morphology of the films has been examined by atomic force microscopy (AFM). The ink‐jet processing technology allows printing of arrays of different donor/acceptor compositions on one substrate as well as the subsequent fast optical screening of the electron transfer processes. The investigated films consist of blends of a poly(methyl methacrylate) polypyridyl ruthenium(II ) copolymer (RuPMMA) as electron donor material (p‐type) and C₆₀ fullerene (PC₆₀BM) as well as heptyl viologen (C₇‐V) derivatives as electron acceptor materials (n‐type).

Ink‐jet printing process and investigated donor/acceptor pair (RuPMMA‐PC₆₀BM).     

4-(2-Methoxy-4-(prop-1-enyl)phenoxy)phthalonitrile; synthesis,characterization, Hirshfeld surface analysis and chemical activity studies

This work deals with experimental and theoretical study of the 4-(2-methoxy-4-(prop-1-enyl)phenoxy)phthalonitrile (MPPP). The MPPP was synthesized and characterized by FT-IR and NMR, and X-ray single-crystal determination. Hirshfeld surface analysis revealed the nature of intermolecular contacts, the fingerprint plots and molecular surface contours provided the information about the percentage contribution and bond interactions. The structural data of the molecule in the ground state was calculated using the DFT employing B3LYP/6-311++G(d,p) basis set. The energetic behavior of the organic dye sensitizer MPPP in solvent media was examined. In addition, chemical activity, NLO, net charges by MPA & NPA, MEP and Fukui function analysis were investigated. Based on vibrational analysis, the thermodynamic properties were calculated at different temperatures and corresponding relations between the properties and temperature were obtained.     

Stability,elasticity and electronic structures of Co-Zr binary intermetallic compounds

ABSTRACT

The structural properties, enthalpies of formation and entropic temperatures of five stable Co-Zr intermetallics were systematically investigated by first-principles calculations. The calculated enthalpy of formation was used to measure the phase stability of the Co-Zr intermetallic compounds, and the results reveal that CoZr has the highest phase stability among these Co-Zr compounds. Considering the change of temperature, the entropic temperature T_S was used to illustrate the high-temperature stability of the Co-Zr intermetallic compounds. Additionally, the elastic constants, anisotropy indexes and Debye temperatures have been calculated. According to the calculated anisotropy indexes, CoZr₂ has the highest elastic anisotropy among the Co-Zr binary compounds. Furthermore, the bonding characteristics of these compounds have also been investigated by calculating the electronic structures.     

Computational Aspects of Irreducible Polynomials

Computational Mathematics and Mathematical Physics - We present results on testing the computation of bounds for polynomial divisors and give estimates for their heights. There are also given...     

A Simple Determination of Trinitrotoluene (TNT) Based on Fluorescence Quenching of Rhodamine 110 with FRET Mechanism

Journal of Fluorescence - Sensitive and selective detection of nitroaromatic explosives is an important issue in regard to human health, environment, public security and military issues. In this...     

The Role of Genetic Polymorphism and Other Factors on Clopidogrel Resistance (CR) in an Asian Population with Coronary Heart Disease (CHD)

Clopidogrel is a widely-used antiplatelet drug. It is important for the treatment and prevention of coronary heart disease. Clopidogrel can effectively reduce platelet activity and therefore reduce stent thrombosis. However, some patients still have ischemic events despite taking the clopidogrel due to the alteration in clopidogrel metabolism attributable to various genetic and non-genetic factors. This review aims to summarise the mechanisms and causes of clopidogrel resistance (CR) and potential strategies to overcome it. This review summarised the possible effects of genetic polymorphism on CR among the Asian population, especially CYP2C19 *2 / *3 / *17, where the prevalence rate among Asians was 23.00%, 4.61%, 15.18%, respectively. The review also studied the effects of other factors and appropriate strategies used to overcome CR. Generally, CR among the Asian population was estimated at 17.2–81.6%. Therefore, our overview provides valuable insight into the causes of RC. In conclusion, understanding the prevalence of drug metabolism-related genetic polymorphism, especially CYP2C19 alleles, will enhance clinical understanding of racial differences in drug reactions, contributing to the development of personalised medicine in Asia.