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Now showing items 49 - 62 of 62

  • Vapor-liquid equilibria of CH4, CO2 and their binary system CH4 + CO2: A comparison between the molecular simulation and equation of state

    Yang Zhi   Gong MaoQiong   Zhou Yuan   Dong XueQiang   Li XiaoDong   Li HuiYa   Wu JianFeng  

    An accurate knowledge about phase behaviors of CH4, CO2 and their binary mixture is crucial in fields of natural gas liquefaction and refrigeration applications. In this work, two all-atom force fields of TraPPE-EH and EMP2 were used for the components CH4 and CO2, respectively. Then the vapor-liquid equilibria (VLE) of CH4, CO2 and their binary system were calculated via the NVT- and NpT Gibbs Ensemble Monte Carlo Simulations. Meanwhile the traditional method using Equation of State (EoS) to correlate the VLE properties was also investigated. The EoSs considered in this work were three classic cubic RK, SRK, PR and another advanced molecular-based PC-SAFT equations. For pure components, both molecular simulations and the PC-SAFT EoS could obtain satisfactory predictions for all the saturated properties. However, the saturated liquid densities calculated by the cubic EoSs were not so good. It was also observed that the TraPPE-EH force field had a good representation for CH4 molecule, while the EMP2 force field was not enough accurate to represent CO2 molecules. For the mixture CH4 + CO2, SRK and PR showed the best predictions for the saturated pressure-component property, while good results were also obtained via molecular simulations and PC-SAFT EoS. It was suggested that special combining rules or binary interaction parameters were important to obtain enough accurate prediction of the mixed phase behavior. Compared with the cubic EoS, the PC-SAFT and molecular simulation method showed better adaptabilities for both the pure and mixture systems. Besides, the accurate molecular parameters used in the PC-SAFT and molecular simulations could bring about direct and deep understanding about the molecular characteristics.
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  • Comment on "Assessing water quality of five typical reservoirs in lower reaches of Yellow River,China:Using a water quality index method" by Wei Hou,Shaohua Sun,Mingquan Wang,Xiang Li,Nuo Zhang,Xiaodong Xin,Li Sun,Wei Li,and Ruibao Jia (2016) [Ecological Indicators,61,309-316]

    Azarnivand, Ali  

    Hou et al. (2016) recently developed a water quality index (WQI) for assessing water quality of five typical reservoirs. Despite all the merits of the practical WQI, it suffers from lack of uncertainty consideration; a fact that motivated the present discussion focusing on mitigation of uncertainty in water quality assessment. In this regard, superiority of employing fuzzy WQI (FWQI) rather than crisp WQI is emphasized. Due to robustness of FWQI in handling uncertainties surrounding data acquisition, employment of fuzzy concept can improve water quality assessment and monitoring to generate results which are more consistent with real world conditions. (C) 2016 Elsevier Ltd. All rights reserved.
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  • Sesquiterpenes and acetogenins from the marine red alga Laurencia okamurai.

    Li XiaoDong   Miao FengPing   Li Ke   Ji NaiYun  

    Three new halogenated sesquiterpenes, 10-bromo-7alpha,8alpha-expoxychamigr-1-en-3-ol (1), 10-bromo-beta-chamigren-8-ol (2), and 10-bromo-3-chlorocupar-5-en-2-ol (3), one new C 12-acetogenin, desepilaurallene (7), one new naturally occurring sesquiterpene, 7-hydroxylaurene acetate (4), two known sesquiterpenes, allolaurinterol acetate (5) and laurene (6), and one known C 15-acetogenin, epilaurallene (8), were isolated from the marine red alga Laurencia okamurai collected from the coast of Rongcheng, China. The structures of these compounds were unambiguously established by 1D, 2D NMR and mass spectroscopic techniques. The bioassay results showed that 4, 5 exhibited potent antibacterial activity, and 1, 4, 5 were toxic to brine shrimp.
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  • Sichuan-Tibet Highway Brings Prosperity to Tibetans


    SIXTY-EIGHT years ago, the Song of the Erlang Mountain was a smash hit all over China. It is an ode to the heroic builders of the highway between Sichuan and Tibet, which cuts through towering mountains and spans billowy rivers.
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  • Study on Defects in Fe-Doped SrTiO3 by Positron Annihilation Lifetime Spectroscopy

    JIN Yuanyuan   LI Xiaodong   HAO Yao   LI Jingjing   WANG Zhu  

    SrTi1-xFexO3-δ ceramics were prepared using a traditional solid-state reaction method. From X-ray diffraction(XRD) result, we found that the doped Fe^3+ dissolved in the lattice, and no secondary phase was observed. Cation vacancies in perovskite oxides were identified via positron annihilation lifetime spectroscopy(PALS) measurements. Undoped and Fe-doped SrTiO3 ceramics and single-crystal SrTiO3 were measured by PALS at room temperature. The results show that the main defects in undoped SrTiO3 ceramics are Ti-related defects, and the isolated Ti vacancy lifetime is about 183.4 ps. With the increase of Fe^3+, the concentration of the Ti vacancies decreases accompanied by the appearance of the V^nSr-nV^**O(defect association of Sr vacancies and multiple O vacancies) vacancy defect complexes.
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  • Relation of martensite-retained austenite and its effect on microstructure and mechanical properties of the quenched and partitioned steels

    Wang CunYu   Chang Ying   Li XiaoDong   Zhao KunMin   Dong Han  

    A two-step quenching and partitioning (Q&P) treatment was applied to low-carbon alloy steels. The relation of initial martensite - retained austenite - fresh martensite and its effect on microstructure and mechanical properties were investigated by experiments. The results reveal that the volume fraction of retained austenite can reach the peak value of 17%, and the corresponding volume fractions of initial martensite and fresh martensite are 40% and 43%, respectively, when the tested steel is treated by initial quenching at 330 degrees C, partitioning at 500 degrees C for 60s and final quenching to room temperature. Moreover, the micromorphologies of austenite and martensite become finer with the increasing of initial martensite fraction. The elongation is the highest when the volume fractions of initial martensite and retained austenite are 70% and 11%, respectively, meanwhile, the yield strength increases and tensile strength decreases gradually with the increase of initial martensite fraction, which proves that the mechanical properties including elongation, yield strength and tensile strength are based on the comprehensive effect of the retained austenite fraction, the finer microstructure and austenite stability.
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  • Lie symmetry analysis and some new exact solutions for rotating flow of a second-order fluid on a porous plate

    Fakhar, K.   Yi, Cheng   Ji Xiaoda   Li Xiaodong  

    The Lie symmetry analysis and the basic similarity reductions are performed for the rotating flow of a second-order fluid on a porous plate. The porous character of the plate and non-Newtonian effect of the fluid increase the order of the governing partial differential equations up to order third. Two new exact solutions generated from the similarity transformation to these equations, are provided. A discussion on physical aspects of these solutions is also presented. (c) 2006 Elsevier Ltd. All rights reserved.
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  • Dark energy, by Miao Li, Xiao-Dong Li, Shuang Wang and Yi Wang

    Vogel, Manuel  

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  • Amphiphilic Seven-arm Star Triblock Copolymers with Diverse Morphologies in Aqueous Solution Induced by Crystallization and pH

    Sun Rui   Wang Ying   Gou Pengfei   Zuo Min   Li Xiaodong   Zhu Weipu   Shen Zhiquan  

    Well-defined amphiphilic seven-arm star triblock copolymers containing hydrophobic crystalline poly(epsilon-caprolactone)(PCL) blocks, hydrophobic non-crystalline poly(tert-butyl acrylate)(PtBA) blocks and hydrophilic poly(ethylene glycol)(PEG) blocks were precisely synthesized by a combination of ring-opening polymerization(ROP), atom transfer radical polymerization(ATRP) and "click" reaction. Such star copolymers could self-assemble into "core-shell-corona" micelles and "multi-layer" vesicles depending on the fraction of each block. Meanwhile, the selective hydrolysis of middle PtBA blocks into the poly(acrylic acid)(PAA) blocks allowed the star block copolymers to further change their morphologies of aqueous aggregates in response to pH values.
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  • Abnormal expressed long non-coding RNA IRAIN inhibits tumor progression in human renal cell carcinoma cells

    Wang Zhiqiang   Liu Qian   Li Tieqiang   Li Xiaodong   Zhang Guangwei   Li Yang   Zi Hao  

    Objectives: The long non-coding RNA (lncRNA) IRAIN has been verified to have key roles in tumor biology. The aim of this study was to explore its expression and biological functions in human renal cell carcinoma (RCC) cells. Methods: Quantitative RT-PCR was applied to detect the RNA expression of IRAIN in RCC tissues and cell lines when compared with respective controls. MTT and flow cytometry methods were respectively used to monitor the cell proliferation and apoptosis of 786-O cells after IRAIN was overexpressed. Altered expression of cyclin D1 and Bax was determined by immunoblotting. Xenograft models were finally carried out to confirm the roles of IRAIN in RCC in vivo. Results: IRAIN expression was found to be remarkably decreased in RCC tissues and cell lines. Its overexpression in 786-O cells significantly inhibited cell proliferation and promoted apoptosis. We further demonstrated that cyclin D1 was reduced while apoptosis promoting protein Bax was elevated in IRAIN-overexpressed 786-O cells. Importantly, we found that IRAIN overexpression could suppress in vivo tumorigenesis of RCC, reflected by tumor volume and tumor weight measurement. Conclusion: IRAIN might serve as a novel tumor suppressing lncRNA and a potential therapeutic target in RCC treatment.
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  • Preparation of transparent Y2O3 ceramic by slip casting and vacuum sintering

    Huo Di   Zheng Yanchun   Sun Xudong   Li Xiaodong   Liu Shaohong  

    In the present work transparent Y2O3 ceramics were made by slip casting and vacuum sintering of nanopowders with sodium polyacrylic acid (PAA-Na) as dispersant. The rheological properties of Y2O3 nanopowder slurry were investigated using different amounts of dispersant and solid contents. The microstructures and transmittance of the sintered ceramics were also studied by means of scanning electron microscopy (SEM) and ultra-violet visible spectrometry. The results showed that rheological behaviors of the Y2O3 nanopowder slurry were effectively promoted by sodium polyacrylic acid. Highly dispersive and stable slurries were obtained as the dispersant was added over 1.0 dwb% under the fixed conditions of pH 11 and 45 wt.% solid content. All the slip cast green bodies were sintered into highly dense ceramics after sintering at 1700 degrees C for 5 h in vacuum, wherein the sample added with 1.1% sodium polyacrylic acid exhibited the highest relative density of 99.36% and transmission of 30% at 800 nm wavelength.
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  • A novel compatible fingerprint algorithm based on multi-region alignment

    Yu Peng   Li Guang   Li Xiaodong  

    Most minutiae-based matching algorithms consist of two phases, local match and global match. In the local phase, some corresponding pairs are obtained by comparing the affine-invariable features of minutiae. And then two images are aligned based on the candidate pairs. However, some spurious candidate pairs and the large nonlinear deformation in images lead to the failure in global match. In this paper, we proposed a novel minutiae-based matching scheme which insert a filtering step after the local match to discard the incompatible pairs and renovate the global match by dividing the whole image into small areas according to the location of the candidate pairs. Results on databases of FVC2004 validate our algorithm.
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  • Investigating the possibility of a turning point in the dark energy equation of state

    Hu YaZhou   Li Miao   Li XiaoDong   Zhang ZhenHui  

    We investigate a second order parabolic parametrization, w(a) = W-t + w(a)(a(t) - a)(2), which is a direct characterization of a possible turning in w. The cosmological consequence of this parametrization is explored by using the observational data of the SNLS3 type Ia supernovae sample, the CMB measurements from WMAP9 and Planck, the Hubble parameter measurement from HST, and the baryon acoustic oscillation (BAO) measurements from 6dFGS, BOSS DR11 and improved WiggleZ. We found the existence of a turning point in w at a similar to 0.7 is favored at l sigma CL. In the epoch 0.55 < a < 0.9, w < -1 is favored at 1 sigma CL, and this significance increases near a = 0.8, reaching a 2 sigma CL. The parabolic parametrization achieve equivalent performance to the ACDM and Chevallier-Polarski-Linder (CPL) models when the Akailce information criterion was used to assess them. Our analysis shows the value of considering high order parametrizations when studying the cosmological constraints on w.
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  • The Power of Thinking—The Origins of China’s Re-rise

    LI Xiaodong  

    100 years ago,China was such a plagued country that the West thought it the world’s problem.A century later,China seems to be the Middle Kingdom when it once was one of the most powerful in the world.China’s great transformation origins from its new political and economic thinking,which will also rejuvenate its culture.Politically,China turned to sinicization,after its failed efforts of westernization.In economy,China has still a long road to run for catching up with the West’s modernization,but China has aimed to rejuvenate itself as a rich and powerful state but rather copied the western capitalism like most developing states,or later the eastern European and Soviet communist states.In the end,China turned away from the western democracy while hungering for science,which implied the clash of civilization for some westerners but the harmony for the Chinese.Chinese has been thinking about China and the world’s future in the western way,but in the coming days,China may play its roles as one eastern center of the world’s diversifying civilizations.
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