Binary Nonlinearization of Lax pairs of Kaup-Newell Soliton Hierarchy

Kaup-Newell soliton hierarchy is derived from a kind of Lax pairs different from the original ones. Binary nonlinearization procedure corresponding to the Bargmann symmetry constraint is carried out for those Lax pairs. The proposed Lax pairs together with adjoint Lax pairs are constrained as a hierarchy of commutative, finite dimensional integrable Hamiltonian systems in the Liouville sense, which also provides us with new examples of finite dimensional integrable Hamiltonian systems. A sort of involutive solutions to the Kaup-Newell hierarchy are exhibited through the obtained finite dimensional integrable systems and the general involutive system engendered by binary nonlinearization is reduced to a specific involutive system generated by mono-nonlinearization.Comment: 15 pages, plain+ams tex, to be published in Il Nuovo Cimento

A Coupled AKNS-Kaup-Newell Soliton Hierarchy

A coupled AKNS-Kaup-Newell hierarchy of systems of soliton equations is proposed in terms of hereditary symmetry operators resulted from Hamiltonian pairs. Zero curvature representations and tri-Hamiltonian structures are established for all coupled AKNS-Kaup-Newell systems in the hierarchy. Therefore all systems have infinitely many commuting symmetries and conservation laws. Two reductions of the systems lead to the AKNS hierarchy and the Kaup-Newell hierarchy, and thus those two soliton hierarchies also possess tri-Hamiltonian structures.Comment: 15 pages, late

Shear behaviour of inorganic polymer concrete beams reinforced with basalt FRP bars and stirrups

Inorganic polymer concrete (IPC) reinforced with basalt fibre reinforced polymer (BFRP) was proposed as a promising substitute of conventional reinforced concrete for structures to enhance their sustainability and durability. This paper, for the first time, presents a systematic study, experimental, theoretical and numerical, of shear behaviour of IPC beams reinforced with BFRP bars and stirrups considering the effects of stirrup spacing (S = 80, 100 and 150 mm) and shear span-to-depth ratio (λ = 1.5, 2.0 and 2.5). Result indicates that all BFRP-IPC beams fail in shear as a result of BFRP stirrup rupture and shear-compression failure. Compared to S, λ has a more pronounced influence on shear performance of BFRP reinforced IPC beams, with a maximum reduction of ultimate shear load by 29.4%. The simulation results show good agreement with experimental data, while the theoretical predictions according to existing design provisions for FRP reinforced concrete have a discrepancy of more than 30% with experiments due to lack of consideration of λ. Modified equations taking into account the effect of λ were then derived and used to predict the shear capacity of BFRP reinforced IPC beams, which agrees well with experimental data with an average discrepancy of only around 5%

Observation of an in-plane magnetic-field-driven phase transition in a quantum Hall system with SU(4) symmetry

In condensed matter physics, the study of electronic states with SU(N) symmetry has attracted considerable and growing attention in recent years, as systems with such a symmetry can often have a spontaneous symmetry-breaking effect giving rise to a novel ground state. For example, pseudospin quantum Hall ferromagnet of broken SU(2) symmetry has been realized by bringing two Landau levels close to degeneracy in a bilayer quantum Hall system. In the past several years, the exploration of collective states in other multi-component quantum Hall systems has emerged. Here we show the conventional pseudospin quantum Hall ferromagnetic states with broken SU(2) symmetry collapsed rapidly into an unexpected state with broken SU(4) symmetry, by in-plane magnetic field in a two-subband GaAs/AlGaAs two-dimensional electron system at filling factor around $\nu=4$. Within a narrow tilting range angle of 0.5 degrees, the activation energy increases as much as 12 K. While the origin of this puzzling observation remains to be exploited, we discuss the possibility of a long-sought pairing state of electrons with a four-fold degeneracy.Comment: 13 pages, 4 figure

Time-Dependent Symmetries of Variable-Coefficient Evolution Equations and Graded Lie Algebras

Polynomial-in-time dependent symmetries are analysed for polynomial-in-time dependent evolution equations. Graded Lie algebras, especially Virasoro algebras, are used to construct nonlinear variable-coefficient evolution equations, both in 1+1 dimensions and in 2+1 dimensions, which possess higher-degree polynomial-in-time dependent symmetries. The theory also provides a kind of new realisation of graded Lie algebras. Some illustrative examples are given.Comment: 11 pages, latex, to appear in J. Phys. A: Math. Ge

Realization of Valley and Spin Pumps by Scattering at Nonmagnetic Disorders

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Behaviour of recycled tyre polymer fibre reinforced concrete at elevated temperatures

This paper presents a systematic study on the feasibility of using recycled tyre polymer (RTP) fibres for mitigating the damage of concrete induced by elevated temperatures. A series of tests were conducted to investigate the effect of RTP fibres on mechanical and thermal behaviour, pore pressure build-up and microstructural evolution of concrete exposed to elevated temperatures (20, 105, 250, 400 and 600 °C), based on which the mechanism of RTP fibres in mitigating damage of concrete was explored. Results indicate that the addition of RTP fibres effectively prevented pore pressure accumulation and significantly mitigated damage of concrete at high temperatures as the melting of RTP fibres and thermal incompatibility between RTP fibres and concrete promoted the formation of interconnected pore-microcrack network of concrete. RTP fibre was proved as a promising sustainable alternative to manufactured polymer fibres for enhancing high temperature and fire resistance of concrete. The optimal RTP fibre content was 1.2 kg/m3 considering the damage mitigation efficiency and strength loss

Internal curing of alkali-activated fly ash-slag pastes using superabsorbent polymer

To mitigate autogenous shrinkage that may cause early-age cracking of alkali-activated fly ash-slag (AAFS) concrete, internal curing using superabsorbent polymers (SAP) is employed in this study. AAFS pastes with different SAP dosages (0–0.5%) and slag replacement ratios to fly ash (15–30%) are investigated. Experimental results indicate that with the addition of SAP workability of fresh paste is improved while compressive strength is comparatively reduced. As SAP dosage increases from 0.2% to 0.5%, chemical shrinkage and autogenous shrinkage of AAFS pastes are reduced by around 18% to 45% and 76% to 85%, respectively. Internal curing of SAP is found to lower the heat peak and shift the peak to the right. This indicates the slower hydration rate corresponding to the lower chemo-mechanical deformation (chemical shrinkage), which contributes to the mitigation of autogenous shrinkage. Therefore, internal curing by means of SAP is an efficient method for mitigating autogenous shrinkage in AAFS pastes

Antiviral treatment alters the frequency of activating and inhibitory receptor-expressing natural killer cells in chronic Hepatitis B virus infected patients

Natural killer (NK) cells play a critical role in innate antiviral immunity, but little is known about the impact of antiviral therapy on the frequency of NK cell subsets. To this aim, we performed this longitudinal study to examine the dynamic changes of the frequency of different subsets of NK cells in CHB patients after initiation of tenofovir or adefovir therapy. We found that NK cell numbers and subset distribution differ between CHB patients and normal subjects; furthermore, the association was found between ALT level and CD158b+ NK cell in HBV patients. In tenofovir group, the frequency of NK cells increased during the treatment accompanied by downregulated expression of NKG2A and KIR2DL3. In adefovir group, NK cell numbers did not differ during the treatment, but also accompanied by downregulated expression of NKG2A and KIR2DL3. Our results demonstrate that treatment with tenofovir leads to viral load reduction, and correlated with NK cell frequencies in peripheral blood of chronic hepatitis B virus infection. In addition, treatments with both tenofovir and adefovir in chronic HBV infected patients induce a decrease of the frequency of inhibitory receptor+ NK cells, which may account for the partial restoration of the function of NK cells in peripheral blood following treatment

Optimization of enantioselective production of chiral epichlorohydrin catalyzed by a novel epoxide hydrolase from domestic duck liver by response surface methodology

Enantiopure epichlorohydrin is a valuable epoxide intermediate for preparing optically active pharmaceuticals. In the present study, a novel epoxide hydrolase prepared from domestic duck liver was used as biocatalyst for producing (S)-epichlorohydrin which preparation process was optimized by response surface methodology. Response surface methodology was performed to evaluate the effects of reaction temperature, pH and reaction time on production of (S)-epichlorohydrin by the novel epoxide hydrolase. (S)-epichlorohydrin production was optimized by Box-Behnken. Three reaction parameters were optimized as follows: pH value 7.10, reaction temperature 32.44°C and reaction time11.06 h. The adequately high R2 value 0.9599 and F score 13.29 indicated the statistical significance of the model. The enantioselective excess of (S)-epichlorohydrin after optimization was 86.14% while thepredicted value was 85.55%. In conclusion, enantioselective hydrolysis conditions optimization to enhance optical purity of (S)-epichlorohydrin could be easily and effectively done by response surfacemethodology; the developed production process indicated the novel epoxide hydrolase from domestic duck liver was high efficient biocatalyst for preparing enantiopure epichlorohydrin