Pressure-induced magnetic phase and structural transition in SmSb_(2)

Motivated by the recent discovery of unconventional superconductivity around a magnetic quantum critical point in pressurized CeSb_(2),here we present a high-pressure study of an isostructural antiferromagnetic(AFM) SmSb_(2) through electrical transport and synchrotron x-ray diffraction measurements.At P_(C)~2.5 GPa,we found a pressure-induced magnetic phase transition accompanied by a Cmca→P4/nmm structural phase transition.In the pristine AFM phase below P_(C),the AFM transition temperature of SmSb_(2) is insensitive to pressure;in the emergent magnetic phase above P_(C),however,the magnetic critical temperature increases rapidly with increasing pressure.In addition,at ambient pressure,the magnetoresistivity(MR) of SmSb_(2) increases suddenly upon cooling below the AFM transition temperature and presents linear nonsaturating behavior under high field at 2 K.With increasing pressure above P_(C),the MR behavior remains similar to that observed at ambient pressure,both in terms of temperature-and field-dependent MR.This leads us to argue an AFM-like state for SmSb_(2) above P_(C).Within the investigated pressure of up to 45.3 GPa and the temperature of down to 1.8 K,we found no signature of superconductivity in SmSb_(2).

Preparation and characterization of porous TiO_2/ZnO composite nanofibers via electrospinning

Porous TiO2/ZnO composite nanofibers have been successfully prepared by electrospinning technique for the first time.It was generated by calcining TiO2/ZnCl2/PVP[PVP：polyvinyl pyrrolidone）]nanofibers,which were electrospun from a mixture solution of TiO2,ZnCl2 and PVP.Transmission electron microscopy（TEM） and X-ray diffraction（XRD） analyses were used to identify the morphology of the TiO2/ZnO nanofibers and a formation of inorganic TiO2/ZnO fibers.The porous structure of the TiO2/ZnO fibers was characterized by N2 adsoption/desorption isotherm.Surface photovoltage spectroscopy（SPS） and photocatalytic activity measurements revealed advance properties of the porous TiO2/ZnO composite nanofibers and the results were compared with pure TiO2 nanofibers,pure ZnO nanofibers and TiO2/ZnO nanoparticles.

Construction of a Set of Cadmium(Ⅱ) Coordination Polymers with Atza and 2,2′-Bipy or 1,10-Phen Ligands (Atza=5-Aminotetrazole-1-acetato Anion)

Reactions of CdX2（X=NO3-, ClO4-） with Hatza （atza=5-aminotetrazole-1-acetato anion） and 2,2′-bipyridine （2,2′-bipy） or 1,10-phenanthroline （1,10-phen） in a methanol/aqueous solution produced a set of new Cd（Ⅱ） coordination polymers, {[Cd（atza）（H2O）（2,2′-bipy）]ClO4}n （1）, {[Cd（atza）（H2O）（1,10-phen）]ClO4 }n （2）, {[Cd（atza）（H2O）（2,2′-bipy）]NO3}n （3） and {[Cd（atza）2 （1,10-phen）]·0.5H2O}n （4）. Single-crystal X-ray diffraction analysis reveals that each Cd（Ⅱ） ion has a distorted octahedral coordination geometry in 1-4, and the Cd（Ⅱ） ion centers are connected through the tridentate atza bridging ligands to form a 2D layer （1-3） or ID chain （4） structure. The fluorescent properties of 2 and 4 are also discussed.

Application of Mean-Field Jordan-Wigner Transformation to Antiferromagnet System

By using the mean-field Jordan-Wigner transformation analysis,this paper studies the one-dimensionalspin-1/2 XYZ antiferromagnetic chain in the transverse field with uniform long-range interactions among the z-components of the spins.The thermodynamic quantities,such as Helmholtz free energy,the internal energy,the specificheat,and the isothermal susceptibility,are obtained.Under degenerating condition,our results agree with numericalresults of the other literatures.

Entanglement Resonance of End Spins in Different Spin Chains

The entanglement resonance in anisotropic spin-1/2 Heisenberg chains of different couplings is investigated when the nearest neighbor coupling is periodically modulated with external magnetic held. When the modulation frequency equals twice of the magnetic held, the entanglement resonance is larger than that at other modulation frequencies and decreases as the number of spins in the chain increases. When the modulation frequency equals the magnetic held, the entanglement resonance can be reduced to a quite low value by varying the couph'ng along z axis.

Effects of Unequal Couplings on Fidelity of a Quantum Controlled-Controlled-Not Gate

由数字地解决一个 three-nuclear-spin 系统的 Schödinger 方程，效果不一致近邻居(NN ) 量 controlled-controlled-not (CCN ) 的忠实上的相互作用门为一个数字起始的状态和重叠被调查起始的状态分别地。它从我们的模拟被发现联合 δJ 到联合 J 的 NN 的 NN 的偏差的比率应该比 0.0005 小保证量 CCN 门的高保真度。

Exchange coupling and helical spin order in the triangular lattice antiferromagnet CuCrO_2 using first principles

The magnetic and electronic properties of the geometrically frustrated triangular antiferromagnet CuCrO2 are investigated by first principles through density functional theory calculations within the generalized gradient approxi- mations （GGA）＋U scheme. The spin exchange interactions up to the third nearest neighbours in the ab plane as well as the coupling between adjacent layers are calculated to examine the magnetism and spin frustration. It is found that CuCrO2 has a natural two-dimensional characteristic of the magnetic interaction. Using Monte Carlo simulation, we obtain the Neel temperature to be 29.9 K, which accords well with the experimental value of 24 K. Based on non- collinear magnetic structure calculations, we verify that the incommensurate spiral-spin structure with （110） spiral plane is believable for the magnetic ground state, which is consistent with the experimental observations. Due to intra-layer geometric spin frustration, parallel helical-spin chains arise along the a, b, or a＋ b directions, each with a screw-rotation angle of about I20°. Our calculations of the density of states show that the spin frustration plays an important role in the change of d-p hybridization, while the spin-orbit coupling has a very limited influence on the electronic structure.

Highly active cobalt-doped nickel sulfide porous nanocones for high-performance quasi-solid-state zinc-ion batteries

Flexible quasi-solid zinc-ion batteries(ZIBs)have large potential in power applications due to the low price,wearable nature,safety,and high capacity.However,the use of transition metal sulfide cathodes in ZIBs has not been studied extensively and the underlying mechanism and theoretical basis of this type of batteries are not well understood.Herein,a highly active cobalt-doped Ni_(3)S_(2) porous nanocone framework(C12NS)is designed and demonstrated as a zinc-ion battery electrode.First-principles calculation and experiments reveal that the cobalt dopant improves the battery properties greatly.The assembled flexible zinc-ion battery exhibits a high specific capacity of 453.3 mAh g^(−1)at a current density of 0.4 A g^(−1)in as well as excellent cycling stability as manifested by a capacity retention ratio of 89.5%at a current density of 4 A g^(−1)after 5000 cycles.The peak energy density of 553.9 Wh kg^(−1)is also superior to those of most recently reported NiCo-based zinc-ion batteries.More importantly,the flexible battery can be operated under severe mechanical bending and even continues to work after physical puncturing without showing leakage.These exciting results not only reveal a novel design of cathode materials for zinc-based batteries,but also suggest their immense commercial potential in portable and wearable electronics.

Multiferroic phase transitions in manganites RMnO_3:A two-orbital double exchange simulation

The semi-quantum two-orbital exchange model is used to investigate the effect of small rare-earth ion substitution on orthorhombic RMnO 3 with A-type antiferromagnetic order,using the Monte Carlo algorithm,exact diagonalization,and zero-temperature optimization approaches.It is revealed that the substitution results in a rich multiferroic phase diagram where the coexisting A-type antiferromagnetic phase and spiral spin phase,pure spiral spin phase,coexisting spiral spin phase,the E-type antiferromagnetic phase,and the pure E-type antiferromagnetic phase emerge in sequence.The multiferroic phase transitions modulate substantially the electric polarization,which is consistent qualitatively with recent experiments.

Multipartite Entanglement Transfer from Multi-Mode Coherent State to Spin Qubits

到旋转 qubits 的从连续可变系统的多国参加的纠纷转移被调查。我们选择多模式是的协调的地连续的可变的地。qubits 不能从多模式为结束的状态获得分成三部分的纠纷到 GHZ 状态，这被发现协调的地。而且， qubits 获得的能力为近到 W 状态的状态的分成三部分的纠纷和从连续可变系统的由两部组成的纠纷被取决于多模式的阶段协调的地。

Quantum Discord and Entanglement in Heisenberg XXZ Spin Chain after Quenches

Using the adaptive time-dependent density-matrix renormalization group method,the dynamics of entanglement and quantum discord of an one-dimensional spin-1/2 XXZ chain is studied when anisotropic interaction quenches are applied at different temperatures.The dynamics of the quantum discord and pairwise entanglement between the nearest qubits shows that the entanglement and quantum discord will first oscillate and then approach to a constant value.The quantum discord can be used to predict the quantum phase transition,while the entanglement cannot.

Insights into the Ti^(4+) doping in P2-type Na_(0.67)Ni_(0.33)Mn_(0.52)Ti_(0.15)O_(2) for enhanced performance of sodium-ion batteries

Due to the sodium abundance and availability,sodium-ion batteries(SIBs)have the potential to meet the worldwide growing demand of electrical energy storage.P2-type sodium transition-metal layer oxides with a high energy density are considered as the most promising cathode materials for SIBs.We present here a detailed study of the enhanced rate capability and cyclic stability of the Ti-doped Na_(0.67)Ni_(0.33)Mn_(0.67)O_(2)cathode material.The combined analysis of ex-situ X-ray absorption fine structure(XAFS)spectroscopy,aberration-corrected high resolution transmission electron microscopy(AB-HRTEM)and X-ray diffraction(XRD)show that the strong Ti–O bond in the transition metal layers stabilizes the local structure,destroy the Na+-vacancy ordering and arrest the irreversible multiphase transformation that occurs during the intercalation/deintercalation process.Actually,Na_(0.67)Ni_(0.33)Mn_(0.52)Ti_(0.15)O_(2)exhibits a reversible capacity of 89.6 mA h g^(-1)even at 5 C,an excellent cyclability with 88.78%capacity retention after 200 cycles at 0.5 C.This study provides a better understanding in optimization of the design of high-energy cathode materials based on titanium doped layered oxides for SIBs.

Optical constants of DUV/UV fluoride thin films

High-refractive-index materials LaF3, NdF3, and GdF3 and low-refractive-index materials MgF2, A1F3, and Na3A1F6 single thin films are deposited by a resistive-heating boat at different depositing rates and specific substrate temperatures on single crystal MgF2 substrates. Transmittances of all fluoride thin films are measured using commercial spectrometer in the ambient atmosphere and under vacuum using synchrotron radiation instrument in the wavelength region from 190 to 500 am. The optical constants of these materials are determined by envelope method and iterative algorithm on the basis of transmittance measurements.

Direct Electrochemistry of Hemoglobin Based on Fe3O4@SiO2 Nanoparticles Modified Electrode

A biosensor based on hemoglobin-Fe304@SiO2 nanoparticle bioconjunctions modified indium-tin-oxide （Hb/Fe3O4@SiOz/ITO） electrode was fabricated to determine the concentration of H202. UV-vis absorption spectra, fourier transform infrared （FT-IR） spectroscopy, cyclic voltammetry （CV） and high-resolution transmission electron microscopy （HRTEM） were used to characterize the bioconjunction of Fe3O4@SiO2 with Hb. Experimental results demonstrate that the immobilized Hb on the Fe3O4@SiO2 matrix retained its native structure well. In addition, Fe3O4@SiO2 nanoparticles （NPs） are very effective in facilitating electron transfer of the immobilized enzyme, which can be attributed to the unique nanostructure and larger surface area of the Fe304@SiO2 NPs. The biosensor displayed good performance for the detection of H2O2 with a wide linear range from 2.03×10^-6 to 4.05×10^3 mol/L and a detection limit of 0.32 μmol/L. The resulting biosensor exhibited fast amperometric response, good stability, reproducibility, and selectivity to H2O2.

Phase Diagram of the Spin-1/2 Heisenberg Alternating Chain in a Magnetic Field

By using the infinite time-evolving block decimation, we study quantum fidelity and entanglement entropy in the spin-1/2 Heisenberg alternating chain under an external magnetic field.The effects of the magnetic field on the fidelity are investigated, and its relation with the quantum phase transition(QPT) is analyzed.The phase diagram of the model is given accordingly, which supports the Haldane phase, the singlet-dimer phase, the Luttinger liquid phase and the paramagnetic phase.The scaling of entanglement entropy in the gapless Luttinger liquid phase is studied, and the central charge c = 1 is obtained.We also study the relationship between the quantum coherence, string order parameter and QPTs.Results obtained from these quantum information observations are consistent with the previous reports.

Synthesis and Structural Characterization of Two Lead（Ⅱ） Complexes of Bis（3,5-dimethylpyrazolyl）methane

Reactions of lead（Ⅱ） nitrate or perchlorate with bis（3,5-dimethylpyrazolyl）methane （dmpzm）, produced two new Pb（Ⅱ） chelated complexes [Pb（dmpzm）2X2] （X=NO3^- 1, ClO4^- 2）. Both compounds were structurally characterized by elemental analysis, IR spectroscopy, thermal analysis, and single crystal X-ray diffraction. Both compounds are mononuclear with a distorted square antiprismatic PbN4O4 coordination geometry incorporating a pair of O,O＇-bidentate anions and N,N＇-bidentate dmpzm ligands. In the crystals of 1 or 2, the methyl or methylene groups of dmpzm ligand interact with the oxygen atoms of nitrates or perchlorates to afford intra- and intermolecular hydrogen bonding, thereby forming a two-dimensional network 1 or a three-dimensional structure 2.

PxSy nanoparticles encapsulated in graphene as highly reversible cathode for sodium ion batteries

Herein,phosphorus-mediated sulfur nanoparticles encapsulated in reduced graphene oxide nanosheets(P-SrGO-T)were successfully synthesized as the cathode for sodium ion battery by a ball milling and the following thermal treatment.A series of covalent bonds,such as P–S,C–S–C,C–O–P and C–S–P,are formed in this process,which are in favor of fixing the sulfur and suppressing the parasitic shuttle effect of polysulfide.Benefiting from the graphene sheets and these covalent bonds,a high reversible capacity of 637.4 m Ah/g was achieved in P-SrGO-T after 100 cycles at the current density of 0.2 A/g.In addition,P-SrGO-T also delivers a high-rate capacity(330.7 m Ah/g at 5 A/g)attributing to low charge transfer resistance and faster ion diffusion kinetic.This work pushes the progress forward in developing phosphosulfide cathode for sodium ion batteries.

Dielectric study on membrane adsorption and release: Relaxation mechanism and diffusion dynamics

Dielectric monitoring of the adsorption or release process of salicylic acid (SA) by chitosan membrane shows that the dielectric spectra of the chitosan membrane/ SA solution systems change regularly in the adsorption or release process. By analyzing the regularity, a new mechanism for the relaxations is proposed. The concentration polarization layer (CPL) caused by SA adsorption or release is confirmed to be essential for the dielectric relaxations. The changes of the spectra with time are explained by account of the relationship between CPL properties and dielectric strength. Based on this relaxation mechanism, a theoretical method can be established to calculate dynamical parameters of inner structure of the adsorption or release systems from their dielectric spectra. Therefore, dielectric spec- troscopy is demonstrated to be a promising method for estimating interfacial distribution of ionic sub- stances and their binding to membrane in a non-invasive way.

Visible light-curable polymers for biomedical applications

Photocurable systems, which offer advantages such as microfabrication and in situ fabrication, have been widely used as dental restorative materials. Because the visible light-curable(VLC) system causes no biological damage, it is popular as a dental material and is being investigated by many researchers for other medical applications. Here, the principle of the VLC system is explained and recent progress in key components including photoinitiators, monomers, macromers, and prepolymers is discussed. Finally, biomedical applications for drug delivery and soft tissue engineering are reviewed. Considering the recent development of VLC systems, its importance in the field of medical applications is expected to continue to increase in the future.

Multiferroicity in Perovskite Manganite Superlattice

Multiferroic properties of short period perovskite type manganite superlattice((R_1MnO_3)n/(R_2MnO_3)n(n=1,2,3)) are considered within the framework of classical Heisenberg model using Monte Carlo simulation. Our result revealed the interesting behaviors in Mn spins structure in superlattice. Apart from simple plane spin cycloid structure which is shown in all manganites including bulk, film, and superlattice here in low temperature, a non-coplanar spiral spin structure is exhibited in a certain temperature range when n equals 1, 2 or 3. Specific heat, spin-helicity vector,spin correlation function, spin-helicity correlation function, and spin configuration are calculated to confirm this noncoplanar spiral spin structure. These results are associated with the competition among exchange interaction, magnetic anisotropy, and Dzyaloshinskii–Moriya interaction.