Synthesis of nanocomposites from cationic polyacrylamide and modified carbon black: Application as flocculants for oily sludge suspension

Carbon black was modified using various liquid‐phase oxidation methods (modified carbon black = m‐CB, m = (1, 2, 3): 1, sulfuric acid/potassium permanganate method; 2, nitric acid method; 3, hydrogen peroxide method). With acetone–ethylene glycol as initiator, dimethyldiallylammonium chloride (DMDAAC) and acrylamide (AM) as monomer, cationic polyacrylamide (CPAM) was prepared by UV excitation of the monomer. The m‐CB/CPAM nanocomposites were synthesized using a hydrothermal method. The factors that affected the molecular weight of CPAM were investigated, including the total monomer concentration, the dosage of the complex initiator, the mass ratio of m_AM:m_DMDAAC and the UV irradiation time. The chemical structures and morphologies of the samples were characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental composition, X‐ray diffraction and scanning electron microscopy. 1‐CB/CPAM was utilized to flocculate oil sludge suspension, and the effects of 1‐CB quality, 1‐CB/CPAM dosage, temperature and pH value on the flocculation performance of 1‐CB/CPAM were investigated. The flocculation mechanism of 1‐CB/CPAM was also analyzed. The results show that 1‐CB/CPAM has an outstanding flocculation effect, and it flocculates oil sludge particles by adsorption bridging and charge neutralization in acidic and alkaline conditions.     

Toward deformation densities for intramolecular interactions without radical reference states using the fragment,atom, localized,delocalized, and interatomic (FALDI) charge density decomposition scheme

A novel approach for calculating deformation densities is presented, which enables to calculate the deformation density resulting from a change between two chemical states, typically conformers, without the need for radical fragments. The Fragment, Atom, Localized, Delocalized, and Interatomic (FALDI) charge density decomposition scheme is introduced, which is applicable to static electron densities (FALDI‐ED), conformational deformation densities (FALDI‐DD) as well as orthodox fragment‐based deformation densities. The formation of an intramolecular NH⋅⋅⋅N interaction in protonated ethylene diamine is used as a case study where the FALDI‐based conformational deformation densities (with atomic or fragment resolution) are compared with an orthodox EDA‐based approach. Atomic and fragment deformation densities revealed in real‐space details that (i) pointed at the origin of density changes associated with the intramolecular H‐bond formation and (ii) fully support the IUPAC H‐bond representation. The FALDI scheme is equally applicable to intra‐ and intermolecular interactions. © 2017 Wiley Periodicals, Inc.     

In beam Mößbauer spectroscopy: 57Fe in semiconductors

Abstract

An overview of results on microscopic properties, implantation features and dynamics of Fe ions implanted into Si, Ge and ZnS as investigated with in beam Mößbauer spectroscopy(IBMS) is given. Potential and limitations of the method are discussed.     

One Way Traffic: Base-to-Backbone Hole Transfer in Nucleoside Phosphorodithioate

The directionality of the hole-transfer processes between DNA backbone and base was investigated by using phosphorodithioate [P(S⁻)=S] components. ESR spectroscopy in homogeneous frozen aqueous solutions and pulse radiolysis in aqueous solution at ambient temperature confirmed initial formation of G^.+-P(S⁻)=S. The ionization potential of G-P(S⁻)=S was calculated to be slightly lower than that of guanine in 5′-dGMP. Subsequent thermally activated hole transfer from G^.+ to P(S⁻)=S led to dithiyl radical (P-2S^.) formation on the μs timescale. In parallel, ESR spectroscopy, pulse radiolysis, and density functional theory (DFT) calculations confirmed P-2S^. formation in an abasic phosphorodithioate model compound. ESR investigations at low temperatures and higher G-P(S⁻)=S concentrations showed a bimolecular conversion of P-2S^. to the σ²-σ*¹-bonded dimer anion radical [-P-2S 2S-P-]⁻ [ΔG (150 K, DFT)=−7.2 kcal mol⁻¹]. However, [-P-2S 2S-P-]⁻ formation was not observed by pulse radiolysis [ΔG° (298 K, DFT)=−1.4 kcal mol⁻¹]. Neither P-2S^. nor [-P-2S 2S-P-]⁻ oxidized guanine base; only base-to-backbone hole transfer occurs in phosphorodithioate.     

Hole/Electron Transporting Materials for Nonfullerene Organic Solar Cells

Nonfullerene acceptor based organic solar cells (NF-OSCs) have witnessed rapid progress over the past few years owing to the intensive research efforts on novel electron donor and nonfullerene acceptor (NFA) materials, interfacial engineering, and device processing techniques. Interfacial layers including electron transporting layers (ETL) and hole transporting layers (HTLs) are crucially important in the OSCs for facilitating electron and hole extraction from the photoactive blend to the respective electrodes. In this review, the lates progress in both ETLs and HTLs for the currently prevailing NF-OSCs are discussed, in which the ETLs are summarized from the categories of metal oxides, metal chelates, non-conjugated electrolytes and conjugated electrolytes, and the HTLs are summarized from the categories of inorganic and organic materials. In addition, some bifunctional interlayer materials served as both ETLs and HTLs are also introduced. Finally, the prospects of ETL/HTL materials for NF-OSCs are provided.     

On tunneling through the black hole horizon

It is shown here that there is no way for particle creation to occur by quantum tunneling through an infinitesimal neighborhood of the black hole horizon. This result is a trivial consequence of the regularity of the horizon, the equivalence principle and the general covariance of the relativistic theory of gravity. Moreover, we also confirm the less trivial statement that no particle creation by quantum tunneling through the black hole horizon is possible independent of the size of the presupposed tunneling domain.     

一步法合成的FeOOH/黑磷纳米复合材料协同实现体系优异的析氧性能

通过水热法，在黑磷(BP)纳米片表面生长FeOOH纳米材料，制备出FeOOH/BP纳米复合材料。作为电化学析氧反应(OER)催化剂，该复合材料在20 mA·cm^-2时的过电位仅为191 mV，Tafel斜率为49.9 mV dec^-1；在循环1 000圈后，过电位仅仅增加了3 mV，且循环过程中元素价态不变，表现出优秀的稳定性。纳米FeOOH负载于BP表面，客观上能隔断氧气对BP的氧化，保护BP的载流子传导性能。同时，生长的FeOOH颗粒尺度小，结晶性弱，这有利于丰富其活性位点，增大活性面积。     

Stencil lithography of gold-black IR absorption coatings

Gold black coatings are deposited through a stencil shadow mask to produce infrared-absorbing patterns with sub-mm lateral dimensions. Such dimensions match the characteristic pitch of Long Wave Infrared (LWIR) array bolometers. Infrared spectral imaging with sub-micron spatial resolution reveals the spatial distribution of absorption across the pattern.     

Quasi-normal modes of extremal black holes from hidden conformal symmetry

In this Letter, we construct the quasi-normal modes of three-dimensional extremal black holes in an algebraic way. We show that the infinite towers of the quasi-normal modes of scalar, vector and tensor could be constructed as the descendents of the highest weight modes. Our investigation shows that the hidden conformal symmetry suggested in Chen et al. (2010) [5] is an intrinsic property of the extremal black hole. Moreover, we notice that we need to fix the freedom in defining the local vector fields and find the right hidden conformal symmetry to obtain the physical quasi-normal modes.