Facile filling of metal particles in small carbon nanotubes for catalysis

A versatile wet chemistry method is developed for filling of subnanometer sized metal particles in carbon nanotubes with a diameter smaller than 1.5 nm. As an example, we showed that a confined bi-component Pd-V catalyst exhibit a higher benzene hydroxylation activity compared with that within multi-walled carbon nanotubes.     

Enhanced cyclability of sulfur cathodes in lithium-sulfur batteries with Na-alginate as a binder

Na-alginate as a binder in an aqueous solvent has been applied in the preparation of sulfur cathodes for lithium-sulfur batteries.Their electrochemical performances have been investigated by a charge-discharge cycle test and electrochemical impedance spectroscopy (EIS).The EIS tests indicated that the alginate sulfur cathode had lower resistance and better kinetic characteristics than those of the poly (vinylidene fluoride) (PVDF) sulfur cathode using PVDF as a binder in a N-methy-2-pyrrolidone (NMP) solvent.The charge-discharge tests showed that the discharge capacity and the capacity retention rate of Na-alginate sulfur cathode were 508 mAh·g-1and 65.4% at the 50th cycle with a current density of 335 mA·g-1.Compared with PVDF sulfur cathode,the alginate sulfur cathode showed a remarkably better cycle performance.These results show that the alginate binder has promising potential for lithium-sulfur battery applications.     

Synthesis of Allyl-Type Selenides and α-Selenoesters in Aqueous Media Promoted by Cadmium

Promoted by metallic cadmium which was produced by reduction of CdCl₂ H₂O with samarium in situ, allyl bromide and α-bromocarboxylates react with diorgano diselenides in aqueous solutions to give allylic-type selenides and α-selenocarboxylates in moderate to good yields.     

Darboux integrability of the stretch-twist-fold flow

The stretch-twist-fold (STF) flow, as a special case of Stokes flows, arises naturally in dynamo theory. The paper studies the integrability of the STF flow. The paper provides a complete classification of the irreducible Darboux polynomials for the system with all values of the parameter alpha. When the parameter is zero, the STF flow is integrable. When the parameter is more than zero, it is proved not to be Darboux integrable. The paper also proves the system has neither exponential factors nor polynomial first integrals at the parameter alpha more than zero.     

The Linear Optical Unambiguous Discrimination of Hyperentangled Bell States Assisted by Time Bin

A linear optical unambiguous discrimination of hyperentangled Bell states is proposed for two‐photon systems entangled in both the polarization and momentum degrees of freedom (DOFs) assisted by time bin. This unambiguous discrimination scheme can completely identify 16 orthogonal hyperentangled Bell states using only linear optical elements, where the function of the auxiliary entangled Bell state is replaced by time bin. Moreover, the possibility of extending this scheme for distinguishing hyperentangled Bell states in n DOFs is discussed, and it shows that $2^{n+k+1}$ hyperentangled Bell states in n ( $n\ge 2$) DOFs can be distinguished with k ( $k<n$) auxiliary entangled states of additional DOFs by introducing a time delay, which decreases the auxiliary entanglement resource required for unambiguous discrimination of hyperentangled Bell state. Therefore, this scheme provides a new way for distinguishing hyperentangled states with current technology, which will extend the application of discrimination of hyperentangled states via linear optics to other quantum information protocols besides hyperdense coding schemes in the future.     

Photoinduced dynamics of a cyanine dye: parallel pathways of non-radiative deactivation involving multiple excited-state twisted transients

Cyanine dyes are broadly used for fluorescence imaging and other photonic applications. 3,3′-Diethylthiacyanine (THIA) is a cyanine dye composed of two identical aromatic heterocyclic moieties linked with a single methine, –CH. The torsional degrees of freedom around the methine bonds provide routes for non-radiative decay, responsible for the inherently low fluorescence quantum yields. Using transient absorption spectroscopy, we determined that upon photoexcitation, the excited state relaxes along two parallel pathways producing three excited-state transients that undergo internal conversion to the ground state. The media viscosity impedes the molecular modes of ring rotation and preferentially affects one of the pathways of non-radiative decay, exerting a dominant effect on the emission properties of THIA. Concurrently, the polarity affects the energy of the transients involved in the decay pathways and further modulates the kinetics of non-radiative deactivation.     

Triphenylphosphine-m-sulfonate/carbon tetrabromide as an easily recoverable catalyst system for the efficient synthesis of xanthene and xanthenone derivatives under solvent-free conditions

A solid complex,readily prepared from commercially available sodium triphenylphosphine-m-sulfonate（TPPMS） and carbon tetrabromide,can be used as an easily recoverable and reusable catalyst system for one-pot condensation of 2-naphthol with aldehydes to construct 14-aryl（alkyl）-14H-dibenzo[a j]-xanthene derivatives and one-pot condensation of 2-naphthol with aldehydes and cyclic 1 3-dicarbonyl compounds to construct 12-aryl（alkyl）-8 9 10 12-tetrahydrobenzo[a]xanthen-11-one derivatives.