Two-dimensional Sb net generated nontrivial topological states in SmAgSb_(2) probed by quantum oscillations

The REAgSb_(2)(RE = rare earth and Y) family has drawn considerable research interest because the two-dimensional Sb net in their crystal structures hosts topological fermions and hence rich topological properties. We report herein the magnetization and magnetotransport measurements of SmAgSb_(2) single crystal, which unveil very large magnetoresistance and high carrier mobility up to 6.2 × 10^(3)% and 5.58 × 10^(3)cm^(2)·V^(-1)·s^(-1), respectively. The analysis of both Shubnikov–de Haas and de Haas–van Alphen quantum oscillations indicates nontrivial Berry phases in the paramagnetic state while trivial Berry curvature in the antiferromagnetic state, indicating a topological phase transition induced by the antiferromagnetic order. It is also supported by the first-principles calculations. The results not only provide a new interesting topological material but also offer valuable insights into the correlation between magnetism and nontrivial topological states.

INVARIANT SUBSPACES AND GENERALIZED FUNCTIONAL SEPARABLE SOLUTIONS TO THE TWO-COMPONENT b-FAMILY SYSTEM

Invariant subspace method is exploited to obtain exact solutions of the two- component b-family system. It is shown that the two-component b-family system admits the generalized functional separable solutions. Furthermore, blow up and behavior of those exact solutions are also investigated.

Synthesis, Crystal Structure, Luminescent Property and DNA-Binding of a Cadmium Complex with 2,4-Bis-oxyacetate-benzoic Acid

A complex [Cd2Na2（BOABA）2（H2O）8]·H2O（1） was synthesized by using 2,4-bisoxyacetate-benzoic acid（H3BOABA） and Cd（OH）2. It was characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. Complex 1 shows a two-dimensional 3-connected rigid plane. The interactions between the ligand and its complex with DNA were studied by Et Br fluorescence probe. Photoluminescent studies indicate that the complex may be excellent candidates for potential photoactive materials.

Two Fluorescent Complexes Assembled by Schiff Base 2-Methoxy-6-(phenyliminiomethyl) Phenolate Ligand

Two d10 metal complexes Zn（NCS）2（C14HI3NO2）2 （1） and [Cd（NO3）2（CI4HI3NO2）2]. 4H20 （2） assembled by 2-methoxy-6-（phenyliminiomethyl） phenolate ligand （C14H13NO2, HL） have been synthesized and characterized by elemental analysis, IR and TG The single-crystal X-ray diffraction studies demonstrated that complex 1 crystallizes in monoclinic, P21/c space group with a = 17.321（7）, b = 11.781（0）, c = 15.593（2） A, fl = 110.273（6）°, V = 2984.95 A3, Z = 4, C30H26N404SzZn, Mr = 636.04, F（000） = 1312, Dc = 1.415 g/cm3,μ（MoKa） = 1.004 mm＂1, the final R = 0.0403 and wR = 0.0900 for 21441 observed reflections with I 〉 20（/）. Complex 2 is of monoclinic system, space group C2/c with a = 16.7767（2）, b = 10.8989（2）, c = 17.4928（2） A, fl = 90.614（9）°, V= 3198.37 A3, Z = 4, C28H34N4O14Cd, Mr= 731.25, F（000） = 1528, Dc = 1.568 g＇cm^-3, μ（MoKa） = 0.757 mm-1, the final R = 0.0361 and wR = 0.0857 for 19811 observed reflections with I 〉 2σ（I）. The two complexes were formed by Schiff base 2-methoxy-6-（phenyliminiomethyl） phenolate ligand and formed a 3D supramolecular architecture by π-πstacking interactions. Moreover, the complexes are luminescent in the solid state. These observations indicate that the complexes are promising system for the development of potential photoactive materials.

Synthesis, Crystal Structure and DNA-binding Property of Bismuth(Ⅲ) Complex with p-Hydroxy-phenylacetic Acid

A bismuth（Ⅲ） complex 1 （H2-4,4＇-bipy）[Bi（HPPA）5]（H2PPA）.4H2O （H2PPA = p- hydroxy- phenylacetic acid, 4,4＇-bipy = 4,4＂-bipyridyl） was hydrothermally synthesized from p-hydroxy-phenylacetic acid （H2PPA）, Bi（NO3）3＂6H20 and 4,4＇-bipyridyl, and characterized by elemental analysis, IR, molar conductivity and TG. The single-crystal X-ray diffraction studies demonstrated that the complex is of monoclinic system, space group P21 with a = 10.928（7）, b = 22.558（7）, c = 11.313（7） A, β = 91.864（4）°, V = 2787.7（4） A3, Z = 2, C58H61BiN2O22, Mr = 1347.07, F（000） = 1364, Dc= 1.605 g/cm-3, p（MoKa） = 3.247 mm-1, the final R = 0.0269 and wR = 0.0540 for 9776 observed reflections with I 〉 2or（I）. The bismuth（I/I） is seven-coordinated with O atoms, forming a monocapped octahedral geometry. Complex 1 further forms a 3D supramolecular architecture by hydrogen bonds and π-π stacking interactions. Moreover, the interaction between the complex and DNA was studied by EtBr fluoescent probe.

Optimal control of a quality supervision profit model for the electronic intermediary

Online customers execute transactions without inspecting products could expect to encounter risks of receiving products with unsatisfactory qualities,especially in food trans-actions.Thus quality supervision plays a key role in the establishment of trust as well as in the management of risk between online customers and sellers.Most papers in this field are in qualitative nature.In this paper,a quality supervision profit(QSP)model is formulated as a discrete-time optimal control problem.It is a quantitative approach,and it broadens the scope.of current research in the area.The quality efort level of online sellers(QELa)and the quality supervision level of the electronic intermediary(QSLm)are considered together with their cor-responding profit in the proposed model.The aim is to optimize an overall profit.A case study arising from Suichang's food traceability system(FTS)of farm produce online transaction is carried out in details.The results reveal that QELs,QSLm and the profit distribution coeffi-cient have a strong influence upon the profits of both sides.Finally,some concluding remarks,including potential further research topics,are given.

Upper bounds on vertex distinguishing chromatic index of some Halin graphs

A vertex distinguishing edge coloring of a graph G is a proper edge coloring of G such that any pair of vertices has the distinct sets of colors. The minimum number of colors required for a vertex distinguishing edge coloring of a graph C is denoted by Xs＇8（G）. In this paper, we obtained upper bounds on the vertex distinguishing chromatic index of 3-regular Halin graphs and Halin graphs with △（G） ≥ 4, respectively.

Is It the Obligation of People with Hiv/Aids to Inform Spouses and Sexual Partners

The Minhang District Court of Shanghai announced the first case of revocation of marital relationship by applying the new provisions of the Civil Code at the beginning of 2021.The defendant was used for failure to disclose to the plaintiff the fact that he was diagnosed with HIV before marriage.In addition,the Minhang Court decided to revoke the marriage relationship of the defendant according to Article 1053 of the Civil Code.As a result,the case aroused widespread concern and discussion at the societal level.The obligation of people with HIV/AIDS to inform their spouses and sexual partners thus entered the level of legal consequences.However,the new provisions of the Civil Code do not simply refer to the problem of HIV/AIDS and do not involve individuals with marital relationships.However,scholars found that many people with HIV/AIDS are unwilling to fulfill the obligation to disclose in practice[1].This scenario motivates the current study to examine the obligation of patients with HIV/AIDS to inform their spouses.

The acyclic chromatic index of planar graphs without 4-,6-cycles and intersecting triangles

A proper edge k-coloring is a mappingΦ:E(G)-→{1,2,...,k}such that any two adjacent edges receive different colors.A proper edge k-coloringΦof G is called acyclic if there are no bichromatic cycles in G.The acyclic chromatic index of G,denoted by Xa(G),is the smallest integer k such that G is acyclically edge k-colorable.In this paper,we show that if G is a plane graph without 4-,6-cycles and intersecting 3-cycles,△(G)≥9,then Xa(G)≤△(G)+1.

Design and synthesis of Fe-Ce-O@C with efficient photocatalytic activity

Fe-Ce-OH@AR14 was obtained via the adsorption of acid red 14(AR14) on Fe-Ce-OH prepared by the codeposition of cerium nitrate hexahydrate,ferric nitrate nonahydrate,and ammonia,and then Fe-Ce-O@C with high photocatalyic efficiency was synthesized by the calcination of Fe-Ce-OH@AR14 in N_(2).For comparison,Fe-Ce-O was also prepared by the calcination of Fe-Ce-OH in N_(2).The obtained materials were characte rized by X-ray diffraction(XRD),Raman,X-ray photoelectron spectroscopy(XPS),Fourier transform infrared spectroscopy(FT-IR),scanning electron miscroscopy(SEM),photoluminescence(PL),ultraviolet-visible diffuse reflectance spectroscopy(UV-vis) techniques and the results show that the band gap of CeO_(2) can be greatly reduced by doping of Fe^(3+),and that loading carbon from the decomposition of AR14 can prolong carrier life,improve the intensity of visible light absorption,and enhance the concentration of oxygen vacancies.The photocatalytic results using AR14 as probe molecule illustrate that using 1% ferric nitrate nonahydrate(the mass percentage of ferric nitrate nonahydrate to cerium nitrate hexahydrate) as dopant and 25 mL of 0.01 mmol/L AR14 as loading carbon resource is helpful for the photocatalytic efficiency of CeO_(2).

Optimal constants for a class of Hausdorff operators on Lebesgue spaces

As the extension of classical Hardy operator and Cesaro operator,Hausdorff operator plays an important role in the harmonic analysis,so it is significant to discuss the boundedness of this kind of operator on various function spaces.The article explores the boundedness of a kind of Hausdorff operators on Lebesgue spaces and calculates the optimal constants for the operators to be bounded on such spaces.In addition,the paper also obtains the necessary and sufficient for a kind of multilinear Hausdorff operators to be bounded on Lebesgue spaces and their optimal constants.

A series of novel Zn(Ⅱ) and Mn(Ⅱ) metal-organic frameworks constructed by 2,4-bis-oxyacetate-benzoic acid: syntheses, structures and photoluminescence

A new carboxylic acid ligand, 2,4-bis-oxyacetate-benzoic acid(H3BOABA), was designed and introduced to construct novel metal-organic framework materials. [Zn Na(BOABA)(phen)(H2O)]·H2O(1), Zn Na(BOABA)(2), Mn3(BOABA)2(phen)2(3), [Mn2(BOABA)(OH)]·(H2O)2(4)(CCDC: 885138, 885137, 894225, 883094) were hydrothermally synthesized and characterized by elemental analysis, IR spectra and thermal gravimetric analyses. Crystal structures of the complexes were determined by single crystal X-ray diffraction method. Complex 1 is a one dimensional double edges non-interpenetrated framework decorated by the phen ligands on the surface. Complex 2 is an unique three dimensional open framework, consisting of Zn(II) and Na(I). Complex 3 is an unique double edges one dimensional MOF containing a [Mn3(BOABA)2(phen)2]n non-interpenetrated structure. Complex 4 is a two dimensional plane structure containing two Mn atoms in the same coordination environment. The interaction between four complexes and DNA were studied by Et Br fluorescence probe. Meanwhile, photoluminescence studies revealed that these four complexes display strong fluorescent emission bands in the solid state at room temperature.

Antimicrobial, anticancer and DNA binding studies of transition metal(Ⅱ)complexes containing 2-phenyl-4-selenazole carboxylic acid

Three novel transition metal complexes [ML2（phen）]＇H20 （M= Mn, Co, Zn; HL= C10H702NSe, 2-phenyl-4-selenazole carboxylic acid, phen= 1,10-phenanthroline） 1-3 were synthesized and characterized by elemental analysis, IR spectra. Their crystal structures were deterimined by single-crystal X-ray diffraction method. The antibacterial activities of the complexes against five species of bacteria, Escherichia coli （E. coli）, Staphylococcus epidermidis （S. epidermidis）, Staphylococcus aureus （S. au- reus）, Acinetobacter baumanii （A. baumanii） and Streptococcus viridans （S. viridans）, were tested respectively. The anticancer activities of the complexes against human pancreatic cancer line PANC-28 and human hepatocarcinoma line HuH7 were also studied. The interactions between the complexes and DNA were studied by ethidium bromide （EB） fluorescent probe.

Backbone Coloring for Triangle-free Planar Graphs

Let G be a graph and H a subgraph of G. A backbone-k-coloring of （G, H） is a mapping f： V（G） → {1,2,…,k} such that If（u）- f（v）｜ ≥ 2 if uv ∈ E（H） and ｜f（u）- f（v） ｜ ≥ 1 if uv ∈ E（G）／E（H）. The backbone chromatic number of （G, H） denoted by Xb（G, H） is the smallest integer k such that （G, H） has a backbone-k-coloring. In this paper, we prove that if G is either a connected triangle-free planar graph or a connected graph with mad（G） 〈 3, then there exists a spanning tree T of G such that Xb（G, T） ≤ 4.

Low-molecular-weight photoresponsive supramulecular hydrogel based on a dicationic azobenzene-bridged pyridinium hydrogelator

Low-molecular-weight supramolecular hydrogels are of significant attractive soft materials as particular functions can be facilely introduced by the straightforward fabrication of such self-assembled systems. In this study, an azobenzene-bridged dicationic pyridinium salt was synthesized, from which photoresponsive supramolecular hydrogel could be fabricated through the π-π stacking and hydrophobic interactions in the aqueous solution. By taking advantages of the UV-vis light induced E/Z photoisomerization behaviors of the incorporated azobenzene photochromophore, reversible gel-sol transformation of such supramolecular hydrogel could be achieved under the alternating UV-vis irradiation conditions. We believed that this photoresponsive supramolecular hydrogel will be a good supplementary in the creation of intelligent soft material.

Nonlocal Symmetries and Conservation Laws of Nonlocal Camassa-Holm Type Equations

The two-component μ-Camassa-Holm equation, the μ-Camassa-Holm equation and the modified μ- Camassa-Holm equation are three nonlocal integrable models. In this paper, it is shown that the two-component μ-Camassa-Holm equation and the μ-Camassa-Holm equation with a linear dispersion admit a kind of nonlocal symmetries, and the modified μ-Camassa-Holm equation does not have such kind of nonlocal symmetry. An number of conservation laws to the modified μ-Camassa-Holm equation and μ-Camassa-Holm equation are obtained.

Research and application of the virtual simulation system teaching method in NC machining course

Virtual simulation technology has become one of the most popular technologies in the field of engineering education after the multimedia information technology in recent years.This paper,based on the comprehensive integrated simulation and verification module of UG NX software,describes and discusses a novel virtual simulation system teaching(VSST)for numerically controlled machining to support the student engineering training to achieve the theoretical knowledge and practical techniques in numerically controlled machining.The findings of a study designed to evaluate the impact of VSST for the development of numerically controlled machining course are presented here.In addition,analysis of the follow-up surveys indicates that the VSST method enables to provide the concrete experience of interaction between the students and the simulation environment and to further stimulate students’interest in learning,so that the students who used VSST achieve significantly higher results than their co-workers.

Injective coloring of planar graphs with girth 5

A coloring of a graph G is injective if its restriction to the neighbour of any vertex is injective.The injective chromatic number x_(i)(G)of a graph G is the least k such that there is an injective k-coloring.In this paper,we prove that for each planar graph with g≥5 and Δ(G)≥20,xi(G)≤Δ(G)+3.

Oscillatory hyper-Hilbert transform along curves on modulation spaces

We consider the boundedness of the n-dimension oscillatory hyper- Hilbert transform along homogeneous curves on the α-modulation spaces, including the inhomogeneous Besov spaces and the classical modulation spaces. The main theorems significantly improve some known results.