High effects of smoke suppression and char formation of Ni?Mo/Mg(OH)2 for polypropylene

The Ni? Mo/Mg(OH)₂ (NMM) hybrid as an efficient flame retardancy and smoke suppression composite for polypropylene (PP) was synthesized through Ni? Mo co‐precipitation on the surface of Mg(OH)₂ (MH) hexagonal nanosheets. Compared to PP/MH, PP/NMM exhibited excellent smoke suppressing and flame retardancy on the heat release rate, total heat release, smoke production rate, total smoke production, CO production rate and total CO production with the same loading. The reduced hazard of PP/NMM was mainly attributed to the high physical barrier effect of compact char residues on heat, smoke and combustible gas. The mechanism study indicated that multiwalled carbon nanotubes (MWCNTs) generated from the catalytic carbonization of PP by the Ni? Mo compound could play the role of “rebar” to strengthen the char residues, avoid the generation of cracks and form highly compact char layer. Furthermore, MgO could facilitate the production of MWCNTs through changing the pyrolysis process of PP and increasing the reaction time between pyrolysis gas and Ni? Mo compound. Hence, the new Ni? Mo/MH catalyst hybrid may explore the potential for solving the tough problem of the flammability and heavy smoke of the polyolefins system.     

Transferring entangled states of photonic cat-state qubits in circuit QED

We propose a method for transferring quantum entangled states of two photonic cat-state qubits(cqubits)from two microwave cavities to the other two microwave cavities.This proposal is realized by using four microwave cavities coupled to a superconducting flux qutrit.Because of using four cavities with different frequencies,the inter-cavity crosstalk is significantly reduced.Since only one coupler qutrit is used,the circuit resource is minimized.The entanglement transfer is completed with a singlestep operation only,thus this proposal is quite simple.The third energy level of the coupler qutrit is not populated during the state transfer,therefore decoherence from the higher energy level is greatly suppressed.Our numerical simulations show that high-fidelity transfer of two-cqubit entangled states from two transmission line resonators to the other two transmission line resonators is feasible with current circuit QED technology.This proposal is universal and can be applied to accomplish the same task in a wide range of physical systems,such as four microwave or optical cavities,which are coupled to a natural or artificial three-level atom.     

La掺杂和空位对ZnS磁性和光学性能影响的第一性原理研究

利用密度泛函理论框架下的平面波超软赝势法,通过第一性原理对La掺杂与Zn空位(V_(Zn))及La掺杂与S空位(V_S)共存的ZnS体系的电子结构、磁性机理、形成能及吸收光谱进行了研究.结果表明, La掺杂与空位(V_(Zn)或V_S)的空间位置最近时,掺杂体系的形成能最低,体系最稳定.另外,La掺杂与Zn空位共存时,体系具有磁性,且体系的净磁矩与La原子与Zn空位的相对位置有关;La掺杂与S空位共存时,掺杂体系无磁性,但此时体系的禁带宽度最窄且吸收光谱红移最显著.     

An improved evaluation of the neutron background in the PandaX-Ⅱ experiment

In dark matter direct detection experiments,neutron is a serious source of background,which can mimic the dark matter-nucleus scattering signals.In this paper,we present an improved evaluation of the neutron background in the PandaX-II dark matter experiment by a novel approach.Instead of fully relying on the Monte Carlo simulation,the overall neutron background is determined from the neutron-induced high energy signals in the data.In addition,the probability of producing a dark-matter-like background per neutron is evaluated with a complete Monte Carlo generator,where the correlated emission of neutron(s)andγ(s)in the(α,n)reactions and spontaneous fissions is taken into consideration.With this method,the neutron backgrounds in the Run 9(26-ton-day)and Run 10(28-ton-day)data sets of PandaX-II are estimated to be(0.66±0.24)and(0.47±0.25)events,respectively.     

Multi-guasiparticle excitations of ~(91)Ru

The level structure in neutron-deficient nucleus 91Ru was investigated via the 58Ni(36Ar,2 plnγ)Ru reaction at a beam energy of 111 MeV.Charged particles,neutrons,and y-rays were emitted in this reaction and detected by the DIAMANT CsI ball,Neutron Wall,and the EXOGAM Ge clover array,respectively.In addition to the previously reported levels in 91Ru,new low-to-medium spin states were observed.Angular correlation and linear polarization measurements were performed to unambiguously determine spins and parities of the excited states in 91 Ru.The low-spin states of 91 Ru exhibit a scheme of multi-quasiparticle excitations,which is very similar to that of the neighboring N=47 isotone.These excitations have been interpreted in terms of the shell model.The calculations performed in the configuration space(p3/2,f5/2,p1/2,g9/2)reproduce the experimental excitation energies reasonably well,supporting the interpretation of the newly assigned positive-parity states in terms of the three quasiparticle configurationsπ(g9/2)^-2v(g9/2^-1 and v(g9/2)^-3.     

Freezing the kinase signaling of breast cancer with transformable peptide nanoparticles

正Protein kinases have been recognized as dominant regulators of all aspects of tumor progression, including tumorigenesis,proliferation, invasion, and metastasis [1]. During the activation of protein kinases, the binding of ligands (e.g., epidermal growth factor, transforming growth factor-α, and amphiregulin) can cause dimerization, which promotes the     

FRET-based ratiometric fluorescent detection of arginine in mitochondrion with a hybrid nanoprobe

A ratiometric fluorescent hybrid nanoprobe CDs-1 for arginine(Arg),exhibiting high sensitivity(the limit of detection,LOD,being 6.5×10^-8 mol/L) and excellent selectivity and anti-interference ability,was fabricated through fluorescence resonance energy transfer(FRET) and the electrostatic attraction between positively-charged hemicyanine molecules and negatively-charged carbon dots(CDs).Arg can be quantitatively detected in the concentration range from 6.0×10^-5 mol/L to 2.7×10^-4 mol/L.Further,due to its ability to target mitochondrion and low cytotoxicity,intracellular Arg was succes s fully tracked through ratiometric fluorescence imaging.     

Highly [010]-oriented,gradient Co-doped LiMnPO4 with enhanced cycling stability as cathode for Li-ion batteries

Journal of Solid State Electrochemistry - LiMnPO4 has been attracting attention for high energy density (701 Wh kg−1) and excellent safety. However, LiMnPO4 suffers from the...     

无处不在的化学——化学动力学

Starting from an example of how to extinguish a fire, this article illustrates how chemical dynamics plays a role in our life. It also introduces what is chemical dynamics and the contribution of Dutch chemist Jacobus H. van't Hoff to chemical dynamics. The horse racing analogy is used to illustrate how the amount of reactants, energy, catalysts and other factors affect the chemical reaction rate.     

Separation,Quantification and Structural Study of (+)‐Catechin and (–)‐Epicatechin by Ion Mobility Mass Spectrometry Combined with Theoretical Algorithms

Two catechin epimers and their non‐covalent complexes with γ‐cyclodextrin were studied by using ion mobility coupled with mass spectrometry (IM‐MS). Rapid separation of complexes was achieved with the peak‐to‐peak resolution reaching 0.86 after optimization of IM condition. Collision cross section (CCS) was measured to explore the structural difference of complexes. A gap of 11.75 Ų between two complexes was found. Molecular modeling and theoretical CCS calculation were adopted to explain the measurement results. Two binding ways of both complexes were found and the calculated CCS corresponds accurately to the measured CCS. Quantification of catechins in mixtures was performed and the relative error was less than 15%, indicating the effectiveness of quantification by IM‐MS.