In-situ control of different oxygen fugacity experimental study on the electrical conductivity of lherzolite at high temperature and high pressure

At pressure 1.0-4.0 GPa and temperature 1073-1423 K and under the control of oxygen fugacity (Mo+MoO₂, Fe+FeO and Ni+NiO), a YJ-3000t multi-anvil solid high-temperature and high-pressure apparatus and Solartron-1260 impedance/Gain-Phase analyzer were employed to analyze the electrical conductivity of lherzolite. The experimental results showed that: (1) within the range of the selected frequencies (10³-10⁶ Hz), either as viewed from the relationship between the real or imaginary part of complex impedance and the frequency, or from the relationship between modulus, phase angle and frequency, it can be seen clearly that the complex impedance has a strong dependence on frequency; (2) with the rise of temperature (T), the electrical conductivity (σ) increased, and Lg σ and 1/T follows the Arrhenius relationship; (3) with the rise of pressure, the electrical conductivity decreased, and activation enthalpy and temperature-independent pre-exponential factor decreased as well. And the activation energy and activation bulk volume of the main charge carrier in the lherzolite have been obtained for the first time, which are 1.68±0.02 eV and 0.04±0.01 cm³/mol, respectively; (4) under the given pressure and temperature, the electrical conductivity tends to increase with increasing oxygen fugacity, and under the given pressure, the activation enthalpy and pre-exponential factor tend to decrease with the rise of oxygen fugacity; (5) at 2.0 GPa and the control of the three solid buffers, Mo+MoO₂, Fe+FeO and Ni+NiO, the exponential factors of electrical conductivity variation range with oxygen fugacity are , and the theoretical model for the relationship between the electrical conductivity of lherzolite and the oxygen fugacity under high pressure has been established for the first time; (6) the electrical conduction mechanism of small polarons provides a reasonable explanation to the variation of conductivity of lherzolite with oxygen fugacity.     

Facile preparation,spectral property and application of Ag/ZnO nanocomposites

Research on Chemical Intermediates - In this paper, a one-pot and sustainable method for the preparation of Ag/ZnO nanocomposites in green polyethylene glycol-200 (PEG-200) was reported with silver...     

XANES/EPR Evidence of the Oxidation of Nickel(II) Quinolinylpropioamide and Its Application in Csp3−H Functionalization

An in situ generated oxidation species of nickel quinolinylpropioamide intermediate was produced. Characterization by X-ray absorption near edge structure (XANES) and EPR provides complementary insights into this oxidized nickel species. With aliphatic amides and isocyanides as substrates, a nickel-catalyzed facile synthesis of structurally diverse five-membered lactams could be achieved.     

Protein–Metal-Ion Networks: A Unique Approach toward Metal Sulfide Nanoparticles Embedded In Situ in Nanocomposites

Nanoscale metal sulfides are of tremendous potential in biomedicine. Generally, the properties and performances of metal sulfide nanoparticles (NPs) are highly related to their structures, sizes and morphologies. Recently, a strategy of using sulfur-containing protein–metal-ion networks for preparing metal sulfide embedded nanocomposites was proposed. Within the networks, proteins can play multiple roles to drive the transformation of these networks into protein-encapsulated metal sulfide NPs with ultrasmall size and defined structure (as both a template and a sulfur provider) or metal sulfide NP–protein hydrogels with injecting and self-healing properties (as a template, a sulfur provider, and a gelator) in a controlled manner. In this Concept, the synthesis strategy, the formation mechanism, and the biomedical applications of the gained nanocomposites are presented. Moreover, the challenges and opportunities of using protein–metal ion networks to construct functional materials for biomedical applications are analyzed.     

Quintic time-dependent-coefficient derivative nonlinear Schrödinger equation in hydrodynamics or fiber optics: bilinear forms and dark/anti-dark/gray solitons

Nonlinear Dynamics - Studies on the water waves contribute to the design of the related industries, such as the marine and offshore engineering, while the media with the negative refractive index...     

Size effect of lead-free halide double perovskite on luminescence property

Lead-free halide double perovskites have gathered wide scientific interest since they are environmentally friendly and stable.However,compared to the lead perovskites,their optoelectronic properties are compromised.Herein we report a series of bulk lead-free mixed Bi-In halide double perovskites:Cs_2AgBi_(1-x)In_xCl_6(0x1).The Cs_2AgBi_(0.125)In_(0.875)Cl_6breaks the parity-forbidden transition and retains direct band gap structure,having warm-white light emission,with photoluminescence quantum efficiency(PLQE)of 70.3%,much higher than the PLQE of reported lead perovskite materials.Its exciton self-trapping dynamics is investigated.Meanwhile,the Cs_2AgBi_(0.125)In_(0.875)Cl_6nanocrystals and Cs_2AgBi_(0.125)In_(0.875)Cl_6microcrystals can be synthesized by modified hot injection and rapid cooling crystallization,respectively.The size effect of Cs_2AgBi_(0.125)In_(0.875)Cl_6is studied on the photoluminescence(PL)property.Additionally,the bulk material exhibits excellent stability on exposure to light,humidity and air for more than 3 months.It is a promising candidate as highly efficient warm white-light emitting material for road lighting.     

Generation and Propagation of Optical Superoscillatory Vortex Arrays

Superoscillation is an intriguing wave phenomenon which enables subwavelength features propagating into far field and hence has potential applications in super‐resolution microscopy as well as particle trapping and manipulation. While previous demonstrations mostly concentrate on designing complicated nanostructures for generating uncontrollable superoscillatory functions, here a new technique which allows for creating polynomially shaped superoscillatory functions that contain phase singularity arrays is demonstrated both theoretically and experimentally. Such a technique is implemented in optical experiments for the first time and controllable superoscillatory lobes with feature much below the diffraction limit is achieved. More importantly, a general theoretical framework, which, to our knowledge, has not been reported before, is developed to show how the created superoscillations propagate to a distance of many Rayleigh ranges and eventually disappear when the distance is sufficiently larger. The validity of the model is confirmed by the experiments. The results may trigger further studies in light field shaping and manipulations in subwavelength scale.     

Redox-Active Two-Dimensional Covalent Organic Frameworks (COFs) for Selective Reductive Separation of Valence-Variable,Redox-Sensitive and Long-Lived Radionuclides

We report the first example of 2D covalent organic framework nanosheets (Redox-COF1) for the selective reduction and in situ loading of valence-variable, redox-sensitive and long-lived radionuclides (abbreviated as VRL nuclides). Compared with sorbents based on chemical adsorption and physical adsorption, the redox adsorption mechanism of Redox-COF1 can effectively reduce the impact of functional group protonation under the usual high-acidity conditions in chemisorption, and raise the adsorption efficiency from the monotonous capture by pores in physisorption. The adsorption selectivity for UO₂²⁺ reaches up to unprecedented ca. 97 % at pH 3, more than for any analogous adsorbing material.     

Acceptor-Doping Accelerated Charge Separation in Cu2O Photocathode for Photoelectrochemical Water Splitting: Theoretical and Experimental Studies

Cu₂O is a typical photoelectrocatalyst for sustainable hydrogen production, while the fast charge recombination hinders its further development. Herein, Ni²⁺ cations have been doped into a Cu₂O lattice (named as Ni-Cu₂O) by a simple hydrothermal method and act as electron traps. Theoretical results predict that the Ni dopants produce an acceptor impurity level and lower the energy barrier of hydrogen evolution. Photoelectrochemical (PEC) measurements demonstrate that Ni-Cu₂O exhibits a photocurrent density of 0.83 mA cm⁻², which is 1.34 times higher than that of Cu₂O. And the photostability has been enhanced by 7.81 times. Moreover, characterizations confirm the enhanced light-harvesting, facilitated charge separation and transfer, prolonged charge lifetime, and increased carrier concentration of Ni-Cu₂O. This work provides deep insight into how acceptor-doping modifies the electronic structure and optimizes the PEC process.     

Recent Advances in Iodine-Promoted C−S/N−S Bonds Formation

Sulfur-containing scaffold, as a ubiquitous structural motif, has been frequently used in natural products, bioactive chemicals and pharmaceuticals, particularly C−S/N−S bonds are indispensable in many biological important compounds and pharmaceuticals. Development of mild and general methods for C−S/N−S bonds formation has great significance in modern research. Iodine and its derivatives have been recognized as inexpensive, environmentally benign and easy-handled catalysts or reagents to promote the construction of C−S/N−S bonds under mild reaction conditions, with good regioselectivities and broad substrate scope. Especially based on this, several new strategies, such as oxidation relay strategy, have been greatly developed and accelerated the advancement of this field. This review focuses on recent advances in iodine and its derivatives promoted hybridized C−S/N−S bonds formation. The features and mechanisms of corresponding reactions are summarized and the results of some cases are compared with those of previous reports. In addition, the future of this domain is discussed.