Novel Cyanine Dyes: Synthesis,Characterization and Photosensitization‐Structure Correlation

Novel furo, thieno and pyrrolo[2,3‐b]pyrazole cyanine dyes were synthesized. The structure‐photosensitization properties correlation of the dyes were examined in 95% ethanol solution by absorption spectroscopy. The chemical structure of the starting biheterocyclic compounds and their derived cyanine dyes were confirmed by elemental analysis, IR and ¹H NMR spectroscopy.     

Azocalixarenes: Synthesis, Characterization, Complexation, Extraction, Absorption Properties and Thermal Behaviours

Azocalixarenes, which have a conjugated chromophore azo (–N=N–) group in p-positions, are synthesized in “one-pot” procedures in satisfactory yields. Their structures in the solid and solution are elucidated by UV–vis, FT-IR, ¹H and ¹³C NMR spectroscopic methods as well as elemental analysis techniques. Some of them are complexed with metal ions (alkali, alkaline-earth and transition metal ions) under neutral conditions. A wide variety of applications is expected by the functionalization of the side arms. The selective liquid–liquid extraction of various alkali, alkaline-earth and transition metal cations from the aqueous phase to the organic phase is carried out by using azocalixarenes. Furthermore, the synthesized azocalixarenes are utilized for selective extraction of Fe³⁺ cations from the aqueous phase to the organic phase. The effects of varying pH and solvent upon the absorption ability of azocalixarenes substituted with electron-donating and electron-withdrawing groups at their o-, m-, p-positions are examined. The thermal behaviours of azocalixarenes containing upper rim functionalized groups are investigated by means of thermogravimetry (TG), differential thermal analysis (DTA) and differential thermogravimetry (DTG).     

室温下制备以{211}晶面为主的Ti1-xVxO2薄膜及其可见光催化性能

以金属Ti和V作为靶材,采用直流反应共溅射技术在室温下制备了以{211}晶面为主的锐钛矿相Ti_1-xV_xO₂薄膜,研究了不同V靶功率对Ti_1-xV_xO₂薄膜的薄膜成分、晶相结构和可见光催化性能的影响。研究表明,Ti_1-xV_xO₂薄膜的晶相结构为锐钛矿相,择优取向为(211),而结晶度受V靶功率的影响。随着V靶功率的增加,薄膜中V元素含量逐渐增加,同时,晶粒和沉积速率也逐渐增加。另外,当V靶功率为150 W时,薄膜的表面粗糙度值有一个最大值。V的掺杂导致薄膜的能带间隙变窄,对光的吸收向可见光区偏移,从而有效地改善了薄膜的可见光催化能力。当V靶功率为150 W时,Ti_1-xV_xO₂薄膜的能带间隙值为 2.82 eV,其在2 h的可见光照射下分解了80%的RhB染料。这被归结于能带间隙窄,高能晶面{211}和结晶度高的共同作用。     

氧化锆增韧莫来石复相陶瓷的摩擦磨损行为与磨损机制

研究了氧化锆增韧莫来石得相陶瓷（ＺＴＭ）与氧化铝陶瓷摩擦副在室温至４００℃干摩擦下的摩擦磨损行为与机制。研究表明：ＺＴＭ陶瓷的磨损率随温度的升高而逐渐降低;室温下ＺＴＭ陶瓷的磨损机制以微观切削和微观断裂为主;随着温度的升高,ＺＴＭ陶瓷中的玻璃相具有微观润滑作用,其磨损机制转变为微观断裂和晶粒剥落为主;偶件氧化铝的磨损机制主要是脆性断裂及晶粒剥落。     

Soliton excitations and chaotic patterns for the (2+1)-dimensional Boiti-Leon-Pempinelli system

By improved projective equation approach and a linear variable separation approach, a new family of exact solutions of the (2+1)-dimensional Boiti-Leon-Pempinelli (BLP) system is derived. Based on the derived solitary wave solution, some dromion and solitoff excitations and chaotic behaviours are investigated.     

Some analytical results for congestion in subscriber line modules

In modern telephone exchanges, subscriber lines are usually connected to the so-called subscriber line modules. These modules serve both incoming and outgoing traffic. An important difference between these two types of calls lies in the fact that in the case of blocking due to all channels busy in the module, outgoing calls can be queued whereas incoming calls get busy signal and must be re-initiated in order to establish the required connection. The corresponding queueing model was discussed recently by Lederman, but only the model with losses has been studied analytically. In the present contribution, we study the model which takes into account subscriber retrials and investigate some of its properties such as existence of stationary regime, derive explicit formulas for the system characteristics, limit theorems for systems under high repetition intensity of blocked calls and limit theorems for systems under heavy traffic.     

An investigation of paddle wheel Cu2(μ2-O2CCH3)4 for gas molecule adsorptions

Metal organic frameworks (MOFs) have been well-known and extensively researched due to the high storage /good selectivity for gas molecules. Herein, the structures and electron paramagnetic resonance (EPR) spectra for dicopper paddle wheel MOF compound (Cu₂(µ₂-O₂CCH₃)₄ with various gas molecule are theoretically investigated by density functional theory (DFT) calculations. The adsorption energies and isotherms (including pure gas molecules and the mixed ones) are calculated for the gas molecules interacting with the unsaturated Cu₂(µ₂-O₂CCH₃)₄. Both quantities exhibit the roughly consistent orders (e.g. H₂S?>?NH₃?>?CO₂?>?CO?>?H₂O?>?N₂?>?NO?>?H₂ for isotherms and H₂S?>?NH₃?>?N₂?>?CO₂?>?NO?>?H₂O?>?H₂?>?CO for adsorption energies), possibly suggesting that this material may act as a potential adsorbent of these gas molecules. The catalytic property of Cu₂(µ₂-O₂CCH₃)₄ for oxidation of CO and NO into non-toxic molecules and splitting of H₂O into H₂ and O₂ in the solvent condition are uniformly discussed. Simulation of Grand Canonical Monte Carlo (GCMC) in MS 8.0 and calculations in Langmuir model reveal that Cu₂(µ₂-O₂CCH₃)₄ has good selectivity for CH₄ in natural gas (CH₄/CO₂/N₂) and SO₂ in fog (SO₂/NO/NO₂/H₂O/O₂), which would exhibit potential environmentally friendly applications.     

Theory prediction of the electronic structure,mechanical and thermodynamic properties of Ca5Pd6Ge6 under pressure

The electronic structures, mechanical and thermodynamic properties of Ca₅Pd₆Ge₆ under pressure have been investigated via the first-principles calculations. The optimised lattice constant was in good agreement with the experimental data. Resulting from the Ca-3d, Ge-4p and Pd-4d states contribution, at the Fermi level, the Ca₅Pd₆Ge₆ exhibits metallic behaviour. The elastic constants were calculated, and the result implies that Ca₅Pd₆Ge₆ was mechanically stable below 50?GPa. The polycrystalline modulus increases almost linearly with pressure. The B/G ratio indicated that Ca₅Pd₆Ge₆ was brittle, and the brittle to ductile transition occurs at 2.5?GPa. Furthermore, the Debye temperature θ_D, the minimum thermal conductivity K was obtained. Finally, the isochoric heat capacity C_v and entropy S were evaluated by the quasi-harmonic Debye model in consideration for the temperature effect.     

Terpolymerization of maleic anhydride, trans-stilbene and acrylic monomers

The results of radical terpolymerization of maleic anhydride (MA), trans-stilbene (Stb) and acrylic monomers (n-butyl methacrylate (BMA) and acrylonitrile (AN)) as acceptor-donor-acceptor monomer systems are discussed. The structure and composition of terpolymers are determined by chemical (acid number for MA units) and elemental (content of N for AN units and O for BMA units) analyses, as well as by FTIR spectroscopy through recorded analytical absorption bands for MA (1770 and 1845 cm⁻¹), Stb (864 cm⁻¹) and BMA (1730 cm⁻¹) units, respectively. The considerable change in the terpolymer compositions is observed when a strong acceptor MA is substituted with BMA (or AN), having comparatively low acceptor character in the system studied. Copolymerization constants for the MA ? Stb complex and acrylic comonomers pairs are determined according to the modified Kelen-Tüdös equation. Obtained results show that at the chosen ratios of comonomers, radical terpolymerization proceeded mainly by a true “complex” mechanism in the stage of near binary copolymerization of MA ? Stb complexed monomers with free BMA (or AN). The kinetics of terpolymerization and terpolymer compositions are studied in the low and high conversion stages. It is shown that for the MA-Stb-BMA system the dependence of R_p on the concentration of individual comonomers has extreme character, while for BMA-Stb-AN this dependence does not have similar character. This fact indicated that terpolymerization in the BMA-Stb-AN system proceeds according to a classical statistical copolymerization mechanism. The terpolymer composition-thermal behaviour relationships are also studied by differential scanning calorimetry and thermogravimetric analysis methods.     

Chemical behaviours of 3-[1''''-chloro-3''''-(2"-phenyl-1",3"-oxazol-5"-one-4"-ylidene)propen-l''''-yl]coumarin towards some nucleophilic reagents

The chemical behaviours of 3-[1'-chloro-3'-(2"-phenyl-1",3"-oxazol-5"-one-4"-ylidene)-propen-1'-yl]coumarin towards nucleophilic reagents (such as hydrolysis,aminolysis,hydroxyl-aminolysis,methanolysis and hydrazinolysis) were described.