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Two new antimony sulfate chlorides named (NH4)2SbCl(SO4)2and (NH4)SbCl2(SO4) were successfully synthesized through solvent-free synthesis method. (NH4)2SbCl(SO4)2exhibits a three-dimensional framework constructed of [SbCl(SO4)2]2–chains and NH4+ions. And the NH4+cations play the role of charge balance and provide the hydrogen bond constructed with oxygen atoms. (NH4)SbCl2(SO4) shows a two-dimensional layer structure that is composed of the regularly stacked [SbCl2(SO4)]−chains via hydrogen-bonding interactions. Both of the titled compounds possess the same chemical composition and the similar Sb–Cl–SO4chains, while hydrogen-bonding interactions and lone-pair cations play the synergistic effect on the framework structures and macroscopic centricities resulting in that the (NH4)2SbCl(SO4)2is centrosymmetric and the (NH4)SbCl2(SO4) is non-centrosymmetric (NCS). Powder second harmonic generation (SHG) measurements indicated that the NCS compound (NH4)SbCl2(SO4) is type I phase-matchable and exhibits SHG responses of ∼1.7 times that of KH2PO4.

NiFe2O4 powders were synthesized by a facile hydrothermal method at 180°C followed by a thermal treatment at 300°C. The phase composition and morphology were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results showed that the NiFe2O4 powders were well-crystallized, and they possessed a particle size in the range of 50-100 nm. The electrochemical property was characterized via cyclic voltammetry (CV) and constant current charge-discharge method. Encouragingly, the NiFe2O4 powders had an excellent electrochemical property, whose specific capacitance reached 266.84 F/g at the electric current density of 1 A/g due to the small particle size. Compared with other Fe-based metal compound oxides, NiFe2O4 has a better electrochemical performance, which can be widely used in the supercapacitor electrode materials.

Fe2O3 nanoparticle was prepared by a hydrothermal method, and the influence of rare earth elements (Y3+, Nd3+ and La3+) on the electrochemical performance was studied. The crystal structure and microstructure of the synthesized lithium zinc ferrite were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM). The results show that the powder is well crystallized and the particles are mostly irregular.The electrochemical property was characterized via cyclic voltammetry (CV) and constant current charge-discharge method. The capacitance of the Fe2O3 nanoparticle is 258.3 F/g, 342.7 F/g after doping Y3+ ,337.1 F/g after doping Nd3+and 331.2 F/g after doping La3 +. The results show that the rare earth elements (Y3+, Nd3+ and La3+) after the specific capacitance has increased, more suitable for super capacitor materials.

A method to synthesize boron nitride (BN) coating on the surface of graphene has been developed. BN coating was synthesized by the direct reaction of sodium borohydride and ammonium chloride at a relatively low temperature of 600 °C. Synthesized sample was characterized by RAM, XRD, FESEM, TEM and XPS. It is revealed that the BN coating combines with graphene through van der Waals interactions, and the elements B and N distribute homogeneously on the surface of graphene. Thermogravimetric analysis showed that the oxidation resistance of the graphene was improved after being coated with BN.

Due to the remarkable physical and mechanical properties of graphene, it is considered to be one of the most promising reinforcements for structural ceramics. In this paper, the composite material is compacted by hot pressing and the effects of mechanical stirring and ultrasonic on dispersion of graphene in alumina matrix were investigated, which was believed to have a great influence on the mechanical properties of the hot-pressed composites. It is found that from Scanning electron microscopy (SEM) observation. Compared with ultrasonic, the composite, in which graphene was dispersed by mechanical stirring, showed higher bending strength (555.1MPaVS432.3MPa) and fracture toughness (4.4MPa·m1/2 VS 4.1MPa·m1/2). The result is much more promising to be employed in the designing and processing of graphene composites.

Developing efficient catalytic materials for electrochemical water splitting is important. Herein, uniformly dispersed and size-controllable iridium (Ir) nanoparticles (NPs) were prepared using a nitrogen-functionalized carbon as the support (Ir/CN). We found that nitrogen functionalization can simultaneously modulate the size of Ir NPs to substantially enhance the catalytically active sites and adjust the electronic structure of Ir, thereby promoting electrocatalytic activity for water splitting. Consequently, the as-synthesized Ir/CN shows excellent electrocatalytic performance with overpotentials of 12 and 265 mV for hydrogen and oxygen evolution reactions in basic medium, respectively. These findings may pave the way for designing and synthesizing other similar materials as efficient catalysts for electrochemical water splitting.

Three new formic-borates Na(COOH)[B(OH)3](H2O)2(1), K3(COOH)3[B(OH)3]2(2), and (HCOOH)3[B(OH)3]2·3H2O (3), containing two types of planar π-conjugated BO3and HCOO groups, have been synthesized via systematic investigations in A–HCOO–BO3(A = alkali metal) systems using hydrothermal methods. Compounds 1and 2crystallize in the centrosymmetric space groups Pnmaand C2/c, and compound 3crystallizes in the non-centrosymmetric space groups Pn, respectively. All the three titled compounds exhibited three-dimensional (3-D) frameworks with a parallel arrangement of B(OH)3and HCOO planar π-conjugated units through hydrogen bonding assisted construction. Particularly, compounds 2and 3showed a graphite-like layer structure. In compound 1, the Na(COOH)[B(OH)3] chains are connected with water molecules by hydrogen bonding to form the 3-D framework. In 2, graphite-like {(COOH)3[B(OH)3]2}3–layers composed of HCOO and B(OH)3groups construct the 3-D framework through the bridging of charge-balance cations K+located at the interlayer space. Compound 3exhibits a 3-D framework through the lattice water molecules and graphite-like (HCOOH)3[B(OH)3]2layers interconnecting with each other via hydrogen bonding. By further comparison, the size of Na+, K+cations and water molecules brought the discrepancy and affected the framework structure and centricity of the three titled compounds. Second harmonic generation (SHG) studies indicated that compound 3has moderate SHG responses of approximately 0.7 times that of KH2PO4(KDP). The UV–vis diffuse reflectance spectroscopy of the powder samples indicated that the short-wavelength absorption edges of all three compounds were below 200 nm, and they are potential deep-UV optical materials.

In signal detection theory (SDT), the well-known Green’s area theorem establishes an equivalence between the area under the receiver operating characteristic (ROC) curve with the hit probability ( H ) and the false-alarm probability ( F ) in the yes–no paradigm and the proportion of correct responses ( P c ) of an unbiased observer in the two-alternative forced-choice (2AFC) paradigm. This theoretical note extends Green’s area theorem from the 2AFC to the specified ‘ M + N ’, which is a generalization of many sensory discrimination forced-choice methods including the 2AFC as its special case. It is demonstrated that the area under the ROC curve with the hit probability h ( H ,N) and the false-alarm probability f ( F ,M) equals the P c of an unbiased observer in the specified ‘ M + N ’. An analytical expression of a general psychometric function for the specified ‘ M + N ’ is derived. A logistic variant of the general psychometric function is also provided. [ABSTRACT FROM AUTHOR]