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April 15,2017
Volume 10,Issue 7
Pages -
Subject Area:Catalytic Reaction Engineering,Coordination Chemistry,Electromagnetism,Condensed Matter Physics,Algebra,Computational Mathematics

Title: Clean synthesis of methylene diphenyl diisocyanate

Authors: FENG Lei, XU Yuanyuan, ZHANG Hongqi, LIU Ran, ZHANG Dongsheng, WANG Yanji
PP: 810-817
Abstract: Methylene diphenyl diisocyanate (MDI) is an important chemical, which plays a key role in the production of rigid polyurethane. In this paper, clean synthesis process of MDI was studied by using dimethyl carbonate (DMC) and 4,4’-methylenebis(2-ethylbenzenamine) (MDA) as raw materials, through thermal decomposition of methylene diphenyl dimethylcarbamate (MDC) to produce MDI. We found that 92.23% yield of MDC and 89.60% yield of MDI were obtained under optimized reaction conditions. Based on the above results, a new catalytic route would be developed for simultaneous synthesis of MDC and ZnO materials, using the obtained ZnO materials as catalyst in the reaction of MDC decomposition to clean synthesis of MDI.
Keywords: catalytic reaction engineering; methylene diphenyl dimethylcarbamate; methylene diphenyl diisocyanate; clean synthesis

Title: Synthesis of a two-dimensional cobalt coordination polymer and its catalytic properties for ethylene selective oligomerization

Authors: FENG Guangliang, CHENG Achao, HAN Yang, HU Yanping, ZHANG Ying
PP: 803-809
Abstract: A two-dimensional cobalt metal organic coordination polymer (CoBTC) was synthesized using a solvothermal method and evacuated under different temperatures to generate a series of CoBTC catalysts for ethylene selective oligomerization. The physicochemical properties of the CoBTC material were characterized by several techniques including thermogravimetric (TG), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). The effects of oligomerization reaction parameters, including n(Al)/n(Co), pressure and cocatalysts, on the catalytic activities and oligomers distribution were investigated. Results demonstrated that the CoBTC catalytsts exhibited the optimal ethylene oligomerization activity of 3.73×105 g•mol-1(Co) •h-1 with C8 selectivity of 98.68%.
Keywords: petroleum chemical engineering; metal organic coordination polymer; ethylene oligomerization; C8 selectivity

Title: Color tuning and mechanism for symmetric/asymmetric Ir(III) phosphorescent complexes bearing aldehyde group

Authors: TIAN Zhuanzhuan, GUO Haoran, YANG Xiaolong, ZHOU Guijiang
PP: 794-802
Abstract: Employing two different 2-phenylpyridine-type ligands with aldehyde group, four symmetric/asymmetric Ir(III) phosphorescent complexes have been developed. Both changing the substitution position of the aldehyde group and asymmetric structure can tune the phosphorescence color of the Ir(III) phosphorescent complexes. Critically, changing the substitution position of the aldehyde group are much more effective in meeting the purpose, since the phosphorescent emission maxima can be shifted ca. 100 nm. Theoretical results indicate that the electron-accepting ability of the aldehyde group can be affected greatly by electronic features of its substitution position. When substituted on electron-deficient position, aldehyde group can change the orientation of the charge-transfer process to form more stabilized metal to ligand charge transfer (MLCT) states, which induce the red-shift effect in phosphorescence wavelength of the Ir(III) complexes. In addition, the phosphorescence wavelength for the asymmetric complexes exhibits red-shift effect compared with that of the symmetric analogs.
Keywords: coordination chemistry; phosphorescent complex; emission color-tuning; aldehyde group; asymmetric; substitution position

Title: Molecular dynamics simulations of cytochrome c and single-walled carbon nanotube interactions

Authors: LIU Haili, TAN Pengli, LI Rongchen, ZHANG Liling, LI Youyong
PP: 785-793
Abstract: In this study, we used molecular dynamics (MD) to investigate the effect of pH value on the structure of cytochrome c and the effect of single-walled carbon nanotube on the structure of cytochrome c under different pH values. We found that the structure of cytochrome c was greatly influenced by acidic condition, and it was more stable in alkaline condition. In alkaline condition, the cavity of cytochrome c is larger, which benefits the formation of electron transfer channel and the contact of heme group and carbon nanotube. Thereby, its redox activity is changed. Adding of single-walled carbon nanotube significantly changed the structure of cytochrome c, which increased the distance between cavity residues and resulted in the instability of the structure of cytochrome c. In the secondary structure, the content of α helix decreased and the 310 helix lost under acidic condition, this conformational change would cause the heme group exposed in the solvent and change the redox activity of cytochrome c. In addition, heme group exposing in the solvent means that single-walled carbon nanotube has potential biological toxicity in acidic condition. This research provided useful reference to the application for single-walled carbon nanotube on mitochondrial disease.
Keywords: polymeric chemistry; structure change; molecular dynamics; cytochrome c; single-walled carbon nanotube

Title: New method for the synthesis of secondary sulfone derivatives and asymmetric synthesis studies

Authors: YU Lei
PP: 777-784
Abstract: An effective approach to synthesis of secondary sulfone derivatives via Michael addition reaction was reported. In this reaction, using α,β-unsaturated ketones as conjugated system and arylsulfinic acid as nucleophile system. This method has advantages of mild reaction condition, high yield, and the product can be obtained after filtration and recrystallization and a gram-scale reaction was successfully performed. Exploration on asymmetric synthesis of secondary sulfones catalyzed by chiral cation-binding polyether catalyst was conducted. The chemical structures of the synthesized compounds were characterized by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy.
Keywords: organic chemistry; sulfone derivatives; asymmetric synthesis; Michael addition reaction; α,β-unsaturated ketones

Title: Living radical polymerization utilizing the direct photolysis of dithiocarbamate

Authors: LI Jiajia, DING Chunlai, LI Na, ZHANG Zhengbiao, ZHU Jian, ZHU Xiulin
PP: 769-776
Abstract: Photo-induced reversible deactivation radial polymerization of methacrylates was performed using 2-(2-cyanopropyl) dithiobenzoate (CPDB) as the initiation-regulation dual functional agent. The polymerization was carried out under mild conditions, such as the irradiation of blue LED light and ambient temperature. Well-controlled polymers with high degree of chain end fidelity and narrow molecular weight distribution were obtained. This polymierzation system also showed well controlled ability for functional methacrylates, such as glycidyl methacrylate (GMA), polyethylene glycol methacrylate (PEGMA), N,N-2-(dimethyl amino)ethyl methacrylate (DMAEMA) and hydroxyethyl methacrylate (HEMA) due to the use of CPDB. The structure of the obtained polymers were characterized by nuclear magnetic resonance (NMR) and matrix assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The possible mechnism was proposed for the current polymerization.
Keywords: polymer chemistry; living radical polymerization; photolysis; dithiocarbamate; ambient temperature

Title: Study on the vibration property of lattice conical shell

Authors: CHEN Liming, DU Bing, YANG Yang
PP: 764-768
Abstract: In this paper, the effect of skin on the vibration property of Kagome lattice conical shell was numerically investigated. Finite element (FE) model of lattice sandwich cylindrical shell was established in ABAQUS and the FE simulation was validated by comparing with the existing experimental results. FE simulation of lattice conical shell was also implemented to get the vibration mode and frequency. Comparison between lattice sandwich conical shell, lattice stiffened conical shell and lattice conical shell were conducted. It is shown that covering with skin can enhance the fundamental frequency of lattice conical shell in the same boundary conditions. Notably, the fundamental frequency of lattice sandwich conical shell is almost triple as high as that of lattice conical shell.
Keywords: solid mechanics; lattice conical shell; sandwich; stiffened; free vibration; fundamental frequency

Title: Analysis on electrostatic force of dielectric and conductor

Authors: LIU Jing
PP: 759-763
Abstract: In this paper, we discussed the electrostatic force of the dielectrics in capacitor both when it is connected with the power supply and when it is isolated, as well as the electrostatic force solving model on the point charge placed by the near charged isolated conductor sphere, in detail. Formulas for these electrostatic forces are given by the virtual displacement method and the method of images, respectively. Through these calculations, the physical essence is revealed. That is the dielectric polarization and the electrostatic induction, caused the attractive force on dielectrics and conductors, respectively, by the electrostatic field. This gives a demonstration for guiding undergraduates to pay attention to the connection and comparison between models explore the physical ideas and to pursue the physical essences in the practice of research-based teaching for Electrodynamics.
Keywords: electromagnetism; electrostatic force; electrodynamics; research-based teaching

Title: Dual-color fiber optic SPR imaging biosensor

Authors: LIU Qiang, LIU Yun, PENG Wei
PP: 755-758
Abstract: In this paper, based on the traditional single color surface plasmon resonance (SPR) imaging sensor, we proposed to use the color selectivity inside the digital camera to extract the Red plane and Green plane gray image data, and the real-time response of the sensor is analyzed from the two color planes. Dual-color SPR imaging sensor is realized. This results increased sensitivity while reducing instrument costs. Based on LabVIEW, real-time image processing system is designed, realizing image processing of region of interest and saving the current picture data during detection process. Experimental results show that the relationship between the relative intensity and refractive index is a linear relation in a range from 1.330 RIU to 1.354 RIU, and the sensitivity is calculated to be -1 033.2%/RIU.
Keywords: optics; fiber optic sensing; dual-color SPR imaging; color selectivity; real-time detection

Title: Investigation of photoelectric conversion efficiency of DSSCs doped with ferroelectric barium titanate nanoparticles

Authors: FENG Keyuan, XIAO Peng
PP: 748-754
Abstract: Dye-sensitized solar cells (DSSCs) are novel solar cells that mimic photosynthesis, the research of which has been a hotspot. In this paper, ferroelectric barium titanate nanoparticles were doped into the photoanode and its effect on the performance of DSSCs were studied. Field emission scanning electron microscope (FESEM) and atomic force microscope (AFM) results showed that the photoanode film had the thickness of about 12 μm and the fluctuation of about 80 nm. J-V data showed that photoelectric conversion efficiency and filling factor reached at 5.39% and 0.71 respectively, when the mixture content of barium titanate was 1% (mass fraction). The parameters increased by 11% and 6% respectively, compared with pure P25 film. In addition, the effect of different proportions of ethyl cellulose on the performance of the cell was studied. It was found that the optimum ratio of ethyl cellulose was 9% by J-V data and dye adsorption amount.
Keywords: condensed matter physics; dye-sensitized solar cells; ferroelectric properties; barium titanate; ethyl cellulose

Title: An optimized algorithm for customized bus site settings and line planning based on immune optimization algorithm and hybrid par-ticle swarm optimization algorithm: a case study of customized public transport in Wuhan city

Authors: TAN Zijian, ZHOU Jingjing, ZHANG Suhua, ZHAO Dongfang
PP: 737-747
Abstract: A hybrid immune optimization algorithm and a hybrid particle swarm optimization algorithm were formed based on immune optimization algorithm and particle swarm optimization algorithm, combined with the advantages of genetic algorithm. Taking customized public transport in Wuhan city as a case study, we researched the customized bus station settings, line planning and other aspects in order to give the scientific and practical guidance to the development of customized public transport, which can be used to provide mathematical basis for further research both in theory and in practice.
Keywords: operational research; customized public transport; genetic algorithm; immune optimization algorithm; hybrid particle swarm optimization algorithm

Title: Structrue of the class of idempotent semiring with involution

Authors: FENG Junqing, LIANG Guohong
PP: 733-736
Abstract: In this paper, a class of idempotent semirings with involution which satisfy the identity is discussed by using the Green-relation in idempotent semirings. The structure of these idempotent semirings are obtained through the involutorial monobisemilattice of semirings. Finally, we show that idempotent semirings with involution satisfy the identity if and only if they are the involutorial monobisemilattice of semirings which additive reduct is rectangular band.
Keywords: algebra; idempotent semiring; idempotent semiring with involution; variety; monobisemilattice

Title: Parallel computation method by alternating three points group explicit difference for nonlinear Leland equation

Authors: FU Yuming, YANG Xiaozhong
PP: 718-732
Abstract: Nonlinear Leland equation is one of Black-Scholes (B-S) option pricing model with transaction costs. The study of the numerical method is of important theoretical significance and practical value. In view of Leland model, we constructed a kind of difference numerical method with intrinsic parallelism: alternating three points group explicit (AGE-3) method. Theoretical analysis demonstrates that AGE-3 difference method of the model is unconditionally stable. The stability of the AGE-3 scheme and the error estimate of the solution are given. The numerical experiment shows that AGE-3 scheme can improve the calculation speed rapidly in contrast with implicit scheme and alternating segment Crank Nicolson (ASC-N) scheme, where 99% time was saved, thus the AGE-3 method can be used to solve the nonlinear Leland equation effectively.
Keywords: financial mathematics; nonlinear Leland equation; alternating three poiats explicit method; parallel computing; numerical experiments

Title: A posteriori error estimate of finite volume elements method with upwind scheme for convection-diffusion-reaction problem

Authors: LIU Xiao, BI Chunjia
PP: 709-717
Abstract: The finite volume element structure is simple, and it keeps the local conservativeness of the numerical flow. The main purpose of this paper is to give posteriori H1 error estimate for Crouzeix-Raviart nonconforming finite volume element method with upwind scheme for convection-diffusion-reaction problem. The main reference is the calculation method of the upwind scheme based on the conforming finite element and the scheme without upwind based on Crouzeix-Raviart nonconforming finite volume element. Using the upwind scheme to treat the convection term, finally, we get the global upper bound of the posteriori error estimator in the H1 norm.
Keywords: computational mathematics; convection-diffusion-reaction equations; finite volume element method; Crouzeix-Raviart nonconforming element; posteriori error estimate

Title: Numerical simulation of two-dimensional Riemann problems with the two-stage fourth-order GRP scheme

Authors: DU Zhifang, LI Jiequan
PP: 696-708
Abstract: In this paper, we have proposed a newly developed two-stage fourth-order time discretization for the hyperbolic conservation laws. In addition, a two-stage fourth-order generalized Riemann problem (GRP) scheme was constructed based on it. The newly developed scheme is easy to implement and requires less computational cost compared with other high-order schemes. It shows excellent resolution in the numerical computations. Two-dimensional Riemann problems of the Euler equations are fundamental in the study of the ﬂuid dynamics. Their solutions reveal a lot of ﬂuid phenomena such as Mach reﬂections, spiral formations, interface instabilities and so on. In this paper, we will firstly review the construction of the two-stage fourth-order GRP scheme in detail. Then we will show the performance of the new scheme to resolve the two-dimensional compressible flow by taking it to the simulation of the several classical two-dimensional Riemann problems and compare it with the classical second-order GRP scheme. Results indicate that the new two-stage fourth-order scheme can provide an excellent resolution for the basic structure of the solution. Compared with the second-order scheme, it can also have a great advantage to capture many small-scaled structures along the slip lines.
Keywords: computational mathematics; two-dimensional Riemann problem; two-stage fourth-order scheme; generalized Riemann problem solver; Lax-Wendroff method

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