Numerical Solution for a Variable-Order Fractional Nonlinear Cable Equation via Chebyshev Cardinal Functions

In this paper, a variable-order fractional derivative nonlinear cable equation is considered. It is commonly accepted that fractional differential equations play an important role in the explanation of many physical phenomena. For this reason we need a reliable and efficient technique for the solution of fractional differential equations. This paper deals with the numerical solution of class of fractional partial differential equation with variable coefficient of fractional differential equation in various continues functions of spatial and time orders. Our main aim is to generalize the Chebyshev cardinal operational matrix to the fractional calculus. Finally, illustrative examples are included to demonstrate the validity and applicability of the presented technique.     

A selective optical sensor for antimony based on hexagonal mesoporous structures

Mesostructured materials show promise in fabricating ordered sensing systems in a reproducible manner. Here, the fabrication of optically selective and sensitive sensors up to subnanomolar concentrations of Sb(III) ions was reported via simple and reproducible techniques in which the hexagonal mesoporous silicas in powder and monolith forms were used as probe carriers. Evidence of successful fabrication of the optical sensors was investigated by extensive characterizations using powder X-ray diffraction, nitrogen adsorption/desorption isotherms, 29Si NMR spectroscopy, and transmission electron microscopy. The mesostructured features allowed high adsorption capacity and accessibility of probe molecules and efficient transport of toxic species via much more direct and easier diffusion to the network sites without significant alteration of their physical characteristics, leading to excellent sensing systems in terms of stability and sensitivity with rapid response time of detection. In addition, the high performance of the hexagonal sensors was dependent on key factors such as the number of support-based sensors, the reaction temperature, and the pH value that led to possible naked-eye detection of Sb(III) ion concentration with a detection limit as low as 3x10(-9) mol/dm3 and a wide detection range of 1 ppb-2 ppm. Of particular interest was that our mesostructured sensor design provided control over the retention of the potential functionality of the naked-eye sensing system of Sb(III) ions upon the storage and even after several regeneration and reuse cycles, indicating large-scale reversibility of sensing systems.     

B12N12纳米笼：潜在的二氧化氮检测传感器

利用密度泛函理论通过计算吸附能量、HOMO/LUMO能隙变化、电荷转移、结构扭曲等研究二氧化氮分子在B12N12纳米笼的吸附．此外,通过计算B₁₂N₁₂的电子结合能、Gibbs自由能、态密度和分子表面的静电势研究其稳定性和其它特性．B₁₂N₁₂纳米笼吸附二氧化氮显示三种构型．B₁₂N₁₂团簇的HOMO/LUMO能隙变化对二氧化氮分子的存在非常敏感,从自由团簇的6.84 eV降为NO₂/团簇稳定团簇的3.23 eV．团簇的导电性被极大地提高,表明B₁₂N₁₂纳米簇可能是潜在的二氧化氮气体分子检测传感器.     

Synthesis of Nanoporous Ni‐Co Mixed Oxides by Thermal Decomposition of Metal‐Cyanide Coordination Polymers

A straightforward strategy to prepare nanoporous metal oxides with well‐defined shapes is highly desirable. Through thermal treatment and a proper selection of metal‐cyanide coordination polymers, nanoporous nickel‐cobalt mixed oxides with different shapes (i.e., flakes and cubes) can be easily prepared. Our nanoporous materials demonstrate high electrocatalytic activity for oxygen evolution reaction.     

Simultaneous determination of ofloxacin,tetrahydrozoline hydrochloride,and prednisolone acetate by high-performance liquid chromatography

A simple, specific, and precise high-performance liquid chromatographic method has been developed for the simultaneous determination of ofloxacin (OFX), tetrahydrozoline hydrochloride (THC), and prednisolone acetate (PAC) in ophthalmic suspension using propylparaben (POP) as the internal standard. The mobile phase consists of 0.05 M phosphate buffer-acetonitrile (65:35, v/v), and the pH is adjusted to 2.7 with orthophosphoric acid. A column containing octadecyl silane chemically bonded to porous silica particles (Waters Spherisorb, 5 microm ODS 1, 4.6 x 150 mm) is used as the stationary phase. The detection is carried out using a variable wavelength UV-vis detector set at 210 nm for OFX and THC and 254 nm for POP (internal standard) and PAC. The solutions are chromatographed at a constant flow rate of 1.2 mL/min. Retention times for OFX, THC, POP, and PAC are approximately 2.5, 4.5, 7.8, and 9.5 min, respectively. The relative retention times are approximately 0.14 min for OFX, 0.35 min for THC, 1.00 min for POP, and 1.22 min for PAC. The linearity range and percent recoveries for OFX, THC, and PAC are 24-120, 4-16, and 16-80 microg/mL and 100.48%, 100.34%, and 100.21%, respectively.     

Synthesis of Novel Modified Guanidines: Reaction of Dicyandiamide with Amino Acids,Amides, and Amines in Aqueous Medium

Reaction of dicyandiamide with series of amino acids afforded guanidinyl pyrazolones 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , respectively. Although reaction of dicyandiamide with urea, acetamide, bezamide, allantion, p‐aminobenzoic acid, sulphanilic acid, and adenine gave biguanides 20 , 21 , 22 , 23 , 24 , 25 , 26 , respectively. All compounds have been characterized on the basis of IR and ¹H‐NMR.     

Selective and mild oxidation of sulfides to sulfoxides by H_2O_2 using DBUH-Br_3 as catalyst

<正>DBUH-Br_3 catalyzed selective conversion of sulfides to sulfoxides in the presence of H_2O_2 as oxidizing agent is described.The reaction was performed selectively at room temperature and relatively short reaction times.     

Selective and efficient oxidation of sulfides to sulfoxides using ammonium cerium (IV) nitrate in the presence of a catalytic amount of KBr or NaBr

A wide range of aliphatic or aromatic sulfides are selectively oxidized to the corresponding sulfoxides using ammonium cerium (IV) nitrate (CAN) and a catalytic amount of KBr or NaBr in the presence of wet SiO₂ in CH₂Cl₂ under heterogeneous conditions in moderate to high yields. Correspondence: Mohammad Ali Zolfigol, Faculty of Chemistry, Bu-Ali Sina University, P.O. Box 6517838683, Hamadan, Iran; Kamal Amani, Department of Chemistry, Faculty of Science, University of Kurdistan, P.O. Box 6617715175, Sanandaj, Iran.     

A new binucleating macrocycle incorporating exocyclic oxime groups and its polynuclear complexes

A new binucleating macrocycle incorporating four exocyclic oxime groups, 6,6′-methylene-bis[1,12–di(hydroximino)-2,3;9,10–dibenzo-1,11–diaza-4,8–dithiacyclotridecane] (LH4) has been synthesized, its mononuclear CoIII and hetropolynuclear CoIII-PdII complexes have been prepared. LH4 and its metal complexes have been characterized by elemental analysis, 1H- and 13C-n.m.r., i.r. and mass spectral studies. The elemental analysis, stoichiometry and the spectroscopic data of the mononuclear CoIII complex indicate that the CoIII ions are coordinated by the oxime nitrogen atoms (C=N); PdII ions in the latter complex are coordinated through diaza-dithia moiety on the macrocycle. The mononuclear CoIII complex of LH4 has a 1:1 metal:ligand ratio. All spectral data support the proposed structure of LH4 and its complexes. This revised version was published online in June 2006 with corrections to the Cover Date.     

Triazine herbicide imprinted monolithic column for capillary electrochromatography

Trietazine was selectively separated from aqueous solution containing the competitor molecule cyanazine, which is similar in size and shape to the template molecule. Structural features of the molecularly imprinted column were figured out by SEM. The influence of the mobile‐phase composition, applied electrical field, and pH of the mobile phase on the recognition of trietazine by the imprinted monolithic polymer has been evaluated, and the imprint effect in the trietazine‐imprinted monolithic polymer was demonstrated by an imprinting factor. The optimized monolithic column resulted in separation of trietazine from a structurally related competitor molecule, cyanazine. In addition, fast separation was obtained within 6 min by applying higher electrical field, with the electrophoretic mobility of 2.97 × 10^?8 m²V^?1s^?1 at pH 11.0.