Properties of a class of groups on <Emphasis Type="Italic">Z</Emphasis><Subscript><Emphasis Type="Italic">m</Emphasis></Subscript>

In this paper, we obtain the factorization of direct production and order of group GL(n, Z _m ) in a simple method. Then we generalize some properties of GL(2, Z _p ) proposed by Huppert, and prove that the group \(GL\left( {2,{Z_{{z^\lambda }}}} \right)\) is solvable. We also prove that group GL(n, Z _p ) is solvable if and only if GL(n, Z _p ) is solvable, and list the generators of groups GL(n, Z _p ) and SL(n, Z _p ). At last, we prove that PSL(2, Z _p )(p > 3) and PSL(n, Z _p )(n > 3) are simple.     

Electrical conductivity optimization of the Na3AlF6-Al2O3-Sm2O3 molten salts system for Al-Sm intermediate binary alloy production

Metal Sm has been widely used in making Al-Sm magnet alloy materials. Conventional distillation technology to produce Sm has the disadvantages of low productivity, high costs, and pollution generation. The objective of this study was to develop a molten salt electrolyte system to produce Al-Sm alloy directly, with focus on the electrical conductivity and optimal operating conditions to minimize the energy consumption. The continuously varying cell constant (CVCC) technique was used to measure the conductivity for the Na₃AlF₆-AlF₃-LiF-MgF₂-Al₂O₃-Sm₂O₃ electrolysis medium in the temperature range from 905 to 1055℃. The temperature (t) and the addition of Al₂O₃ (W(Al₂O₃)), Sm₂O₃ (W(Sm₂O₃)), and a combination of Al₂O₃ and Sm₂O₃ into the basic fluoride system were examined with respect to their effects on the conductivity (κ) and activation energy. The experimental results showed that the molten electrolyte conductivity increases with increasing temperature (t) and decreases with the addition of Al₂O₃ or Sm₂O₃ or both. We concluded that the optimal operation conditions for Al-Sm intermediate alloy production in the Na₃AlF₆-AlF₃-LiF-MgF₂-Al₂O₃-Sm₂O₃ system are W(Al₂O₃) + W(Sm₂O₃)=3wt%, W(Al₂O₃):W(Sm₂O₃)=7:3, and a temperature of 965 to 995℃, which results in satisfactory conductivity, low fluoride evaporation losses, and low energy consumption.     

Glass-forming ability,microhardness, corrosion resistance,and dealloying treatment of Mg60-xCu40Ndx alloy ribbons

The influence of Nd addition on the glass-forming ability (GFA), microhardness, and corrosion resistance of Mg_60-xCu₄₀Nd_x (x=5, 10, 15, 20, and 25, at%) alloys were investigated by differential scanning calorimetry, Vickers-type hardness tests, and electrochemical methods. The results suggest that the GFA and microhardness of the amorphous alloys increase until the Nd content reaches 20at%. The corrosion potential and corrosion current density obtained from the Tafel curves indicate that the Mg₃₅Cu₄₀Nd₂₅ ternary alloy exhibits the best corrosion resistance among the investigated alloys. Notably, nanoporous copper (NPC) was synthesized through a single-step dealloying of Mg_60-xCu₄₀Nd_x (x=5, 10, 15, 20, and 25) ternary alloys in 0.04 mol·L-1 H₂SO₄ solution under free corrosion conditions. The influence of dealloying process parameters, such as dealloying time and temperature, on the microstructure of the ribbons was also studied using the surface diffusivity theory. The formation mechanism of dealloyed samples with a multilayered structure was also discussed.     

Activity coefficients of NiO and CoO in CaO-Al2O3-SiO2 slag and their application to the recycling of Ni-Co-Fe-based end-of-life superalloys via remelting

To design optimal pyrometallurgical processes for nickel and cobalt recycling, and more particularly for the end-of-life process of Ni-Co-Fe-based end-of-life (EoL) superalloys, knowledge of their activity coefficients in slags is essential. In this study, the activity coefficients of NiO and CoO in CaO-Al₂O₃-SiO₂ slag, a candidate slag used for the EoL superalloy remelting process, were measured using gas/slag/metal equilibrium experiments. These activity coefficients were then used to consider the recycling efficiency of nickel and cobalt by remelting EoL superalloys using CaO-Al₂O₃-SiO₂ slag. The activity coefficients of NiO and CoO in CaO-Al₂O₃-SiO₂ slag both show a positive deviation from Raoult's law, with values that vary from 1 to 5 depending on the change in basicity. The activity coefficients of NiO and CoO peak in the slag with a composition near B=(%CaO)/(%SiO₂)=1, where B is the basicity. We observed that controlling the slag composition at approximately B=1 effectively reduces the cobalt and nickel oxidation losses and promotes the oxidation removal of iron during the remelting process of EoL superalloys.     

Parameter-Dependent Third-Order Susceptibility of InxGa1-xN/GaN Parabolic Quantum Dots

The electron states confined in wurtzite InxGa1-xN/GaN strained quantum dots （QDs） have been investigated in the effective -mass approximation by solving the Schrtdinger equation, in which parabolic confined potential and strong built-in electric field effect （due to the piezoelectricity and spontaneous polarization） have been taken into account. The real part Rex^（3）（0,0,ω） and the imaginary part Imx^（3）（0,0,ω） of the third-order susceptibil- ity describe quadratic electro-optic effects and electro-absorption process of the QDs respectively. And both of them have been calculated in directions parallel and vertical to z axis. Furthermore, the study shows Rex^（3）（0,0,ω） and Imx^（3）（0,0,ω） increase under resonant conditions with the QDs＇ radius and height increase, and the same results occur when the content increase. In addition, the resonant position shift to the lower energy region when the parabolic frequencies increase.     

Preparation of Al<Subscript>72</Subscript>Ni<Subscript>8</Subscript>Ti<Subscript>8</Subscript>Zr<Subscript>6</Subscript>Nb<Subscript>3</Subscript>Y<Subscript>3</Subscript> amorphous powders and bulk materials

Amorphous Al₇₂Ni₈Ti₈Zr₆Nb₃Y₃ powders were successfully fabricated by mechanical alloying. The microstructure, glass-forming ability, and crystallization behavior of amorphous Al₇₂Ni₈Ti₈Zr₆Nb₃Y₃ powders were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). The isothermal crystallization kinetics was analyzed by the Johnson–Mehl–Avrami equation. In the results, the supercooled liquid region of the amorphous alloy is as high as 81 K, as determined by non-isothermal DSC curves. The activation energy for crystallization is as high as 312.6 kJ·mol?1 obtained by Kissinger and Ozawa analyses. The values of Avrami exponent (n) imply that the crystallization is dominated by interface-controlled three-dimensional growth in the early stage and the end stage and by diffusion-controlled two- or three-dimensional growth in the middle stage. In addition, the amorphous Al₇₂Ni₈Ti₈Zr₆Nb₃Y₃ powders were sintered under 2 GPa at temperatures of 673 K and 723 K. The results show that the Vickers hardness of the compacted powders is as high as Hv 1215.     

Temperature effect on the corrosion and passivation characterization of Ni<Subscript>82.3</Subscript>Cr<Subscript>7</Subscript>Fe<Subscript>3</Subscript>Si<Subscript>4.5</Subscript>B<Subscript>3.2</Subscript> alloy in acidic media

The effects of temperature on corrosion and the electrochemical behavior of Ni_82.3Cr₇Fe₃Si_4.5B_3.2 glassy alloy in HCl, H₂SO₄, and H₃PO₄ acids were studied using AC and DC techniques. Impedance data reveal that the susceptibility to localized corrosion increases with increasing temperature. Potentiodynamic polarization curves reveal that the bulk glassy alloy is spontaneously passivated at all the investigated temperature in H₂SO₄ and H₃PO₄ solutions. A localized corrosion effect in HCl solution is clearly observed. The apparent activation energies in the regions of Tafel, active, and passive, as well as the enthalpies and entropies of the dissolution process were determined and discussed. The high apparent activation energy (E_a) value for H₃PO₄ solution in Tafel region is explained by the low aggressivity of PO₄3- ions.     

On the Dual <Emphasis Type="Italic">p</Emphasis>-Measures of Asymmetry for Star Bodies

Recently, the connection between p-measures of asymmetry and the L_p -mixed volumes for convex bodies was found soon after the p-measure of asymmetry was proposed, and the Orlicz-measures of asymmetry was proposed inspired by such a kind of connection. In this paper, by a similar way the dual p -measures of asymmetry for star bodies (naturally for convex bodies) is introduced first. Then the connection between dual p -measures of asymmetry and L_p -dual mixed volumes is established. Finally, the best lower and upper bounds of dual p-measures and the corresponding extremal bodies are discussed.     

Preparation of In<Subscript>2</Subscript>S<Subscript>3</Subscript> and Cu-Doped In<Subscript>2</Subscript>S<Subscript>3</Subscript> 2D Ultrathin Nanoflakes with Tunable Absorption and Intense Photocurrent Response

We reported an effective method to synthesize In₂S₃ and Cu-doped In₂S₃ two-dimensional ultrathin nanoflakes by the hydrothermal method through tuning the Cu/In molar ratio. The transmission electron microscope images showed that the products had ultrathin flake-like shape with wrinkling and rolling. The X-ray diffraction patterns indicated the crystal phase of nanoflakes was varied from β-In₂S₃ to tetragonal-CuInS₂ as the Cu/In molar ratio was increased. The In₂S₃ nanoflakes exhibited absorption band at 450 nm, while new absorption peaks in turn appeared at 550 nm and 670 nm as the Cu/In molar ratio was increased. In addition, the two-dimensional ultrathin nanoflakes exhibited intense photocurrent response.     

Multi-index analysis of the melting process of laterite metallized pellet

Herein, a multi-index analysis of the nickel content of an alloy, output rate of the alloy, nickel recovery rate, and iron recovery rate during the melting of laterite metallized pellets was performed. The thermodynamic reduction behavior of oxides such as NiO, FeO, Fe₃O₄, and Cr₂O₃ was studied using the FactSage software, which revealed that SiO₂ is not conducive to the reduction of iron oxides, whereas the addition of basic oxides such as CaO and MgO is beneficial for the reduction of iron oxides. On the basis of a comprehensive analysis to achieve greater nickel recovery and lower iron recovery rates, the optimum experimental parameters in the orthogonal experiment were A3B1C3 (t=30 min, C/O=0.4, R=1.2); the indicators w_Ni, φ_alloy, η_Ni, and η_Fe had values of 15.0wt%, 12.1%, 44.9%, and 96.4%, respectively. In single-factor experiments, increasing basicity (R) substantially improved the separation effect in the low-basicity range 0.5 ≤ R ≤ 0.8 but not in the high-basicity range 0.8 ≤ R ≤ 1.2. Similar results were obtained for the effect of the C/O ratio. Moreover, the recovery rate of nickel increased with increasing recovery rate of iron.     

Enantioselective Chlorocyclization of Olefinic Amides with 1,3-Dichloro- 5, 5-Dimethylhydantoin (DCDMH) Catalyzed by (DHQD)<Subscript>2</Subscript>PHAL

An efficient catalytic asymmetric chlorocyclization of olefinic amides with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) using hydroquinidine 1,4-phthalazinediyl diether ((DHQD)₂PHAL) as organocatalyst has been developed. Series of chiral chloro substituted isobenzofuran-1(3H)-imine derivatives were obtained in good yields (up to 85%) and enantioselectivities (up to 70% ee).     

An algorithm for the spectral immunity of binary sequence with period 2<Superscript><Emphasis Type="Italic">n</Emphasis></Superscript>

To resist the fast algebraic attack and fast selective discrete Fourier transform attacks, spectral immunity of a sequence or a Boolean function was proposed. At the same time, an algorithm to compute the spectral immunity of the binary sequence with odd period N was presented, here N is a factor of 2 ⁿ ? 1, where n is an integer. The case is more complicated when the period is even. In this paper, we compute linear complexity of every orthogonal sequence of a given sequence using Chan-Games algorithm and k - error linear complexity algorithm. Then, an algorithm for spectral immunity of binary sequence with period N = 2 ⁿ is obtained. Furthermore, the time complexity of this algorithm is proved to be O(n).     

Analysis of type II toxin-antitoxin genes <Emphasis Type="Italic">all</Emphasis> 3211-<Emphasis Type="Italic">asl</Emphasis> 3212 in <Emphasis Type="Italic">Anabaena</Emphasis> PCC 7120

The type II toxin-antitoxin genes are responsible for the phenotypic switch to a quasi-dormant state that enables cell survival under stresses, a similar function to heterocyst of cyanobacteria. In this paper, we particularly study the role of gene pair all3211-asl3212 under Spectinomycin stress to reveal how the type II toxin-antitoxin involved in environmental stress responses. Bioinformatics prediction shows that toxin protein gene All3211 is homologous to MazF, a member of mazEF family that encoding nucleases. We clone gene all3211-asl3212 into expression vectors to identify its molecular characteristics. Deletion mutant strains of all3211-asl3212 are selected in a tri-parental mating screen. Phenotype comparisons of mutant and wild type reveals no difference of single-deletion-mutants in pigment integrity, the sensitivity to antibiotics, and heterocyst formation. The results show that deletion mutation of single TAS gene pair all3211-asl3212 results in limited effects on the cellular growth of PCC 7120. Thus, we suggest that dosage compensating might be provided from redundant genes or bypass pathways to offset obvious phenotypic differences.     

<Emphasis Type="Italic">L</Emphasis><Subscript>2</Subscript> decay estimate of BCL equation

This paper considers linearized BCL system with viscosity which is firstly derived by J. L. Bona, T. Colin and D. Lannes for the study of motion of water waves. L ₂ decay estimate is got by means of Fourier analysis and frequency decomposition. This result plays key role in studying the global well-posedness of corresponding nonlinear system.     

Vertex disjoint cycles in intersection graphs of bases of matroids

The intersection graph of bases of a matroid M=(E, B) is a graph G=G~I(M) with vertex set V(G) and edge set E(G) such that V(G)=B(M) and E(G)={BB′:|B∩B′|≠0, B, B′∈B(M), where the same notation is used for the vertices of G and the bases of M. Suppose that|V(G~I(M))| =n and k_1+k_2+…+k_p=n, where k_i is an integer, i=1, 2,…, p. In this paper, we prove that there is a partition of V(G~I(M)) into p parts V_1 , V_2,…, V_p such that |V_i| =k_i and the subgraph H_i induced by V_i contains a k_i-cycle when k_i ≥3, H_i is isomorphic to K_2 when k_i =2 and H_i is a single point when k_i =1.     

Molecular phylogenetics of <Emphasis Type="Italic">Gymnocypris</Emphasis> (Teleostei: Cyprinidae) in Lake Qinghai and adjacent drainages

149 complete mitochondrial DNA (mtDNA) cytochrome b (Cyt b) genes (1140 bp) of Gymnocypris przewalskii, Gymnocypris eckloni and Gymnocypris scolistomus from the Lake Qinghai, Yellow River and Qaidam Basin were sequenced and analyzed. Consistent dendrogram indicated that the samples collected from the same species do not constitute a separate monophyletic group and all the samples were grouped into three highly divergent lineages (A, B and C). Among them, Lineage A contained all samples of G. przewalskii from the Lake Qinghai and partial samples of the G. eckloni from the Yellow River. Lineage B contained the remaining samples of G. eckloni from the Yellow River. Lineage C was composed of a monophyletic group by G. eckloni from the Qaidam Basin. Analysis of molecular variance (AMOVA) indicated that most of genetic variations were detected within these three mtDNA lineages (93.12%), suggesting that there are three different lineages of Gymnocypris in this region. Our Cyt b sequence data showed that G. przewalskii was not a polytypic species, and G. scolistomus was neither an independent species nor a subspecies of G. eckloni. The divergent mtDNA lineages of G. eckloni from the Yellow River suggested that gene flow between the different populations was restricted to a certain extent by several gorges on the upper reach of the Yellow River. Lineage B of G. eckloni might be the genetic effect from the ancestor which was incorporated with the endemic schizothoracine fishes when the headward erosion of the Yellow River reached to its current headwaters of late. The G. eckloni from Basin Qaidam was a monophyletic group (lineage C) and F_st values within G. eckloni from the Yellow River were higher than 0.98, suggesting that the gene flow has been interrupted for a long time and the G. eckloni from Basin Qaidam might have been evolved into different species by ecology segregation. The correlation between the rakers number of Gymnocypris and population genetic variation was not significant. All Gymnocypris populations exhibited a low nucleotide diversity (π = 0.00096–0.00485). Therefore the Gymnocypris populations from Basin Qaidam could have experienced severe bottleneck effect in history. Our result suggested Gymnocypris populations of Basin Qaidam should give a high priority in conservation programs.     

Effect of SrCO<Subscript>3</Subscript> addition on the dynamic compressive strength of ZTA

Ceramic parts usually experience dynamic load in armor applications. Therefore, studying the dynamic behaviors of ceramics is important. Limited data are available on the dynamic behaviors of ceramics; thus, it is helpful to predict the dynamic strength of ceramics on the basis of their mechanical properties. In this paper, the addition of SrCO₃ into zirconia-toughened alumina (ZTA) was demonstrated to improve the fracture toughness of ZTA due to the formation of the SrAl₁₂O₁₉ (SA6) phase. The porosity of ZTA was found to be increased by the addition of SrCO₃. These newly formed pores served as the nucleation sites of cracks under dynamic load; these cracks eventually coalesced to form damaged zones in the samples. Although the K IC values of the samples were improved, the dynamic strength was not enhanced because of the increase in porosity; in fact, the dynamic strength of ZTA ceramics decreased with the addition of SrCO₃.     

Enhanced antioxidant capacities <Emphasis Type="Italic">in vivo</Emphasis> caused by the change in key constituent of <Emphasis Type="Italic">Terminalia chebula</Emphasis> Retz. treated with Tibet traditional process

In order to investigate the chemical-biological relationship caused by the special processing technology, the constituent’s content and antioxidant capacity in vivo of Euphorbia fischeriana Steud processing Terminalia chebula Retz. have been tested. Taking T. chebula Retz. as control, the content of gallic acid is analyzed with high performance liquid chromatography (HPLC) method. The results show that the increase of gallic acid concentration from 4.54% to 7.46% leads to enhancement of the antioxidant capacities in vivo of the E. fischeriana Steud processing T. chebula Retz. The significant antioxidant capacity in vivo (p<0.05) of the processed product possesses is better than the unprocessed herb. Its superoxide dismutase (SOD) and malondia-ldehyde (MDA) contents in serum, the MDA content in liver can match the effects of vitamine E when administered at high dosage.     

Fabrication and properties of aluminum silicate fibrous materials with <Emphasis Type="Italic">in situ</Emphasis> synthesized K<Subscript>2</Subscript>Ti<Subscript>6</Subscript>O<Subscript>13</Subscript> whiskers

To improve their mechanical and thermal insulation properties, aluminum silicate fibrous materials with in situ synthesized K₂Ti₆O₁₃ whiskers were prepared by firing a mixture of short aluminum silicate fibers and gel powders obtained from a sol-gel process. During the preparation process, the fiber surface was coated with K₂Ti₆O₁₃ whiskers after the fibers were subjected to a heat treatment carried out at various temperatures. The effects of process parameters on the microstructure, compressive strength, and thermal conductivity were analyzed systematically. The results show that higher treatment temperatures and longer treatment durations promoted the development of K₂Ti₆O₁₃ whiskers on the surface of aluminum silicate fibers; in addition, the intersection structure between whiskers modulated the morphology and volume of the multi-aperture structure among fibers, substantially increasing the fibers' compressive strength and reducing their heat conduction and convective heat transfer at high temperatures.     

<Emphasis Type="Italic">Lp</Emphasis>-dual mixed geominimal surface area

In this paper, a new Lp-dual mixed geominimal surface area is defined by Lp-dual mixed quermassintegrals, which extends the definition of Lp-dual geominimal surface area and generalizes some related inequalities established by Wan and Wang.