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Now showing items 33 - 48 of 56

  • Increased thermostability and phenol removal efficiency by chemical modified horseradish peroxidase

    Liu, Jian-Zhong   Song, Hai-Yan   Weng, Li-Ping   Ji, Liang-Nian  

    Horseradish peroxidase was modified by phthalic anhydride and glucosamine hydrochloride. The thermostabilities and removal efficiencies of phenolics by native and modified HRP were assayed. The chemical modification of horseradish peroxidase increased their thermostability (about 10- and 9-fold, respectively) and in turn also increased the removal efficiency of phenolics. The quantitative relationships between removal efficiency of phenol and reaction conditions were also investigated using modified enzyme. The optimum pH for phenol removal is 9.0 for both native and modified forms of the enzyme. Both modified enzyme could suffer from higher temperature than native enzyme in phenol removal reaction. The optimum molar ratio of hydrogen peroxide to phenol was 2.0. The phthalic anhydride modified enzyme required lower dose of enzyme than native horseradish peroxidase to obtain the same removal efficiency. Both modified horseradish peroxidase show greater affinity and specificity of phenol.
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  • Genomic and transcriptional changes in response to pinene tolerance and overproduction in evolved Escherichia coli

    Niu, Fu-Xing   Huang, Yuan-Bin   Ji, Liang-Nian   Liu, Jian-Zhong  

    alpha-Pinene is an important monoterpene, which is widely used as a flavoring agent and in fragrances, pharmaceuticals and biofuels. Although an evolved strain Escherichia coli YZFP, which had higher tolerance to pinene and titer, has been successfully used to produce high levels of pinene, the pinene titer is much lower than that of hemiterpene (isoprene) and sesquiterpenes (farnesene) to date. Moreover, the overall cellular physiological and metabolic changes caused by higher tolerance to pinene and overproduction of pinene remains unclear. To reveal the mechanism of Escherichia coli YZFP with the higher tolerance to pinene and titer, a comparative genomics and transcriptional level analyses combining with CRISPR activation (CRISPRa) and interference (CRISPRi) were carried out. The results show that the tolerance to pinene and the overproduction of pinene in E. coli may be associated with: 1) the mutations of the DXP pathway genes, the rpoA and some membrane protein genes, and their upregulations of transcription levels; and 2) the mutations of some genes and their down-regulation of transcriptional levels. These comparative omics analyses provided some genetic modification strategies to further improve pinene production. Overexpression of the mutated cbpA, tabA, pitA, rpoA, sufBCDS, mutS, ispH, oppF, dusB, dnaK, dxs, dxr and flgFGH genes further improved pinene production. This study also demonstrated that combining comparative omics analysis with CRISPRa and CRISPRi is an efficient technology to quickly find a new metabolic engineering strategy.
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  • Fatigue life prediction based on crack closure for 6156 Al-alloy laser welded joints under variable amplitude loading

    Liu, Hu   Shang, De-Guang   Liu, Jian-Zhong   Guo, Zhen-Kun  

    A fatigue prediction approach is proposed using fracture mechanics for laser beam welded Al-alloy joints under stationary variable amplitude loading. The proposed approach was based on the constant crack open stress intensity factor in each loading block for stationary variable amplitude loading. The influence of welding residual stress on fatigue life under stationary variable amplitude was taken into account by the change of crack open stress intensity factor in each loading block. The residual stress relaxation coefficient beta =3D 0.5 was proposed to consider the residual stress relaxation for the laser beam welded Al-alloy joints during the fatigue crack growth process. Fatigue life prediction results showed that a very good agreement between experimental and estimated results was obtained. (C) 2014 Elsevier Ltd. All rights reserved.
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  • Fluctuation Characteristics of Spray Velocity Field of Coaxial Convergent Nozzle by Particle-Image-Velocimetry Measurements

    Du, Cong   Liu, Jian-Zhong   Huang, Zhen-Yu   Liu, Lian-Sheng   Zhou, Jun-Hu   Cen, Ke-Fa  

    Coaxial elements and annular liquid jets are normally utilized in industrial applications to generate sprays. A particle image velocimetry investigation on the transient characteristics of the spray velocity field of a coaxial convergent nozzle is carried out in this paper. Based on the measurement results, spectrum analysis is performed to detect the process of atomization in the spray. Experimental results show that at large gas jet velocities, the process of generation of droplets is controlled mainly by the dynamics of liquid ligaments, and the power spectrum reveals that the velocity fluctuations are superimposed on the transient flow field by the effect of the shear layer instability. With the increase of gas velocity, the fluctuations of the spray velocity develop progressively to higher frequencies. [DOI: 10.1115/1.4006172]
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  • Structural insights into the N-terminal GIY-YIG endonuclease activity of Arabidopsis glutaredoxin AtGRXS16 in chloroplasts

    Liu, Xi   Liu, Shian   Feng, Yingang   Liu, Jian-Zhong   Chen, Yuling   Khanh Pham   Deng, Haiteng   Hirschi, Kendal D.   Wang, Xinquan   Cheng, Ninghui  

    Glutaredoxins (Grxs) have been identified across taxa as important mediators in various physiological functions. A chloroplastic monothiol glutaredoxin, AtGRXS16 from Arabidopsis thaliana, comprises two distinct functional domains, an N-terminal domain (NTD) with GlyIleTyr-TyrIleGly (GIY-YIG) endonuclease motif and a C-terminal Grx module, to coordinate redox regulation and DNA cleavage in chloroplasts. Structural determination of AtGRXS16-NTD showed that it possesses a GIY-YIG endonuclease fold, but the critical residues for the nuclease activity are different from typical GIY-YIG endonucleases. AtGRXS16-NTD was able to cleave lambda DNA and chloroplast genomic DNA, and the nuclease activity was significantly reduced in AtGRXS16. Functional analysis indicated that AtGRXS16-NTD could inhibit the ability of AtGRXS16 to suppress the sensitivity of yeast grx5 cells to oxidative stress; however, the C-terminal Grx domain itself and AtGRXS16 with a Cys123Ser mutation were active in these cells and able to functionally complement a Grx5 deficiency in yeast. Furthermore, the two functional domains were shown to be negatively regulated through the formation of an intramolecular disulfide bond. These findings unravel a manner of regulation for Grxs and provide insights into the mechanistic link between redox regulation and DNA metabolism in chloroplasts.
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  • Targeting BCRP/ABCG2 by RNA interference enhances the chemotherapy sensitivity of human colon cancer side population cells

    Hu, Jun   Li, Jian   Yue, Xin   Wang, Jia-cang   Wang, Jun-feng   Liu, Jian-zhong   Kong, Da-lu  

    Relapse and metastasis are frequent in colon cancer and may be linked to stem cell characteristics. This study isolated side population (SP) cells from a colon cancer cell line (Colo-320) and examined their self-renewal and differentiation abilities. Compared to non-SP (NSP) cells, SP colon cancer cells were more tumorigenic in vivo and exhibited more invasive characteristics and a greater ability to form colonies. Additionally, more cells were in G(0)/G(1) phase and more highly expressed the multidrug resistance protein BCRP/ABCG2. We achieved enhanced chemotherapy sensitivity by transfecting SP cells with a hairpin-like, small interfering RNA (siRNA) eukaryotic expression plasmid targeting BCRP/ABCG2.
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  • Synthesis, DNA-binding and photocleavage studies of ruthenium complexes [Ru(bpy)(2)(mitatp)](2+) and [Ru(bpy)(2)(nitatp)](2+)

    Yu, Hui-Juan   Huang, Shu-Mei   Li, Lv-Ying   Jia, Hai-Na   Mao, Zong-Wan   Liu, Jian-Zhong  

    Two new ruthenium complexes [Ru(bpy)(2)(mitatp)](ClO4)(2) 1 and [Ru(bpy)(2)(nitatp)](ClO4)(2) 2 (bpy = 2,2'-bipyridine, mitatp = 5-methoxy-isatino[1,2-b]-1,4,8,9-tetraazatriphenylene, nitatp = 5-nitro-isatino[1,2-b]-1,4,8,9-tetraazatriphenylene) have been synthesized and characterized by elemental analysis, H-1 NMR, mass spectrometry and cyclic voltammetry. Spectroscopic and viscosity measurements proved that the two Ru(II) complexes intercalate DNA with larger binding constants than that of [Ru(bpy)(2)(dppz)](2+) (dppz = dipyrido[3,2-a:2',3'-c]phenazine) and possess the excited lifetime of microsecond scale upon binding to DNA. Both complexes can efficiently photocleave pBR322 DNA in vitro under irradiation. Singlet oxygen (O-1(2)) was proved to contribute to the DNA photocleavage process, the O-1(2) quantum yields was determined to be 0.43 and 0.36 for 1 and 2, respectively. Moreover, a photoinduced electron transfer mechanism was also found to be involved in the DNA cleavage process. (C) 2009 Elsevier Inc. All rights reserved.
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  • Recent Advances in Metabolically Engineered Microorganisms for the Production of Aromatic Chemicals Derived From Aromatic Amino Acids

    Shen, Yu-Ping   Niu, Fu-Xing   Yan, Zhi-Bo   Fong, Lai San   Huang, Yuan-Bin   Liu, Jian-Zhong  

    Aromatic compounds derived from aromatic amino acids are an important class of diverse chemicals with a wide range of industrial and commercial applications. They are currently produced via petrochemical processes, which are not sustainable and eco-friendly. In the past decades, significant progress has been made in the construction of microbial cell factories capable of effectively converting renewable carbon sources into value-added aromatics. Here, we systematically and comprehensively review the recent advancements in metabolic engineering and synthetic biology in the microbial production of aromatic amino acid derivatives, stilbenes, and benzylisoquinoline alkaloids. The future outlook concerning the engineering of microbial cell factories for the production of aromatic compounds is also discussed.
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  • Production of shikimic acid from Escherichia coli through chemically inducible chromosomal evolution and cofactor metabolic engineering.

    Cui, Yan-Yan   Ling, Chen   Zhang, Yuan-Yuan   Huang, Jian   Liu, Jian-Zhong  

    BACKGROUND: Shikimic acid (SA) produced from the seeds of Chinese star anise (Illicium verum) is a key intermediate for the synthesis of neuraminidase inhibitors such as oseltamivir (Tamiflu), an anti-influenza drug. However, plants cannot deliver a stable supply of SA. To avoid the resulting shortages and price fluctuations, a stable source of affordable SA is required. Although recent achievements in metabolic engineering of Escherichia coli strains have significantly increased SA productivity, commonly-used plasmid-based expression systems are prone to genetic instability and require constant selective pressure to ensure plasmid maintenance. Cofactors also play an important role in the biosynthesis of different fermentation products. In this study, we first constructed an E. coli SA production strain that carries no plasmid or antibiotic marker. We then investigated the effect of endogenous NADPH availability on SA production.; RESULTS: The pps and csrB genes were first overexpressed by replacing their native promoter and integrating an additional copy of the genes in a double gene knockout (aroK and aroL) of E. coli. The aroG(fbr), aroB, aroE and tktA gene cluster was integrated into the above E. coli chromosome by direct transformation. The gene copy number was then evolved to the desired value by triclosan induction. The resulting strain, E. coli SA110, produced 8.9-fold more SA than did the parental strain E. coli (DeltaaroKDeltaaroL). Following qRT-PCR analysis, another copy of the tktA gene under the control of the 5P(tac) promoter was inserted into the chromosome of E. coli SA110 to obtain the more productive strain E. coli SA110. Next, the NADPH availability was increased by overexpressing the pntAB or nadK genes, which further enhanced SA production. The final strain, E. coli SA116, produced 3.12 g/L of SA with a yield on glucose substrate of 0.33 mol/mol.; CONCLUSION: An SA-producing E. coli strain that carries neither a plasmid nor an antibiotic marker was constructed by triclosan-induced chromosomal evolution. We present the first demonstration that increasing NADPH availability by overexpressing the pntAB or nadK genes significantly enhances SA production.=20
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  • Enhancing Production of Pinene in Escherichia coli by Using a Combination of Tolerance,Evolution,and Modular Co-culture Engineering

    Niu, Fu-Xing   He, Xin   Wu, Ya-Qin   Liu, Jian-Zhong  

    alpha-Pinene is a natural and active monoterpene, which is widely used as a flavoring agent and in fragrances, pharmaceuticals, and biofuels. Although it has been successfully produced by genetically engineered microorganisms, the production level of pinene is much lower than that of hemiterpene (isoprene) and sesquiterpenes (farnesene) to date. We first improved pinene tolerance to 2.0% and pinene production by adaptive laboratory evolution after atmospheric and room temperature plasma (ARTP) mutagenesis and overexpression of the efflux pump to obtain the pinene tolerant strain Escherichia coli YZFP, which is resistant to fosmidomycin. Through error-prone PCR and DNA shuffling, we isolated an Abies grandis geranyl pyrophosphate synthase variant that outperformed the wild-type enzyme. To balance the expression of multiple genes, a tunable intergenic region (TIGR) was inserted between A. grandis GPPS(D90G/L175P) and Pinus taeda Pt1(Q457L). In an effort to improve the production, an E. coli-E coil modular co-culture system was engineered to modularize the heterologous mevalonate (MEV) pathway and the TIGR-mediated gene cluster of A. grandis GPPS(D90G/L175P) and P. taeda Pt1(Q45)(7L). Specifically, the MEV pathway and the TIGR-mediated gene cluster were integrated into the chromosome of the pinene tolerance strain E. coli YZFP and then evolved to a higher gene copy number by chemically induced chromosomal evolution, respectively. The best E. coli-E coli co-culture system of fermentation was found to improve pinene production by 1.9-fold compared to the mono-culture approach. The E. coli-E coli modular co-culture system of whole-cell biocatalysis further improved pinene production to 166.5 mg/L.
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  • Silencing GmFLS2 enhances the susceptibility of soybean to bacterial pathogen through attenuating the activation of GmMAPK signaling pathway

    Tian, Sheng-Nan   Liu, Dan-Dan   Zhong, Chen-Li   Xu, Hui-Yang   Yang, Shuo   Fang, Yuan   Ran, Jie   Liu, Jian-Zhong  

    The plasma membrane (PM)-localized receptor-like kinases (RLKs) play important roles in pathogen defense. One of the first cloned RLKs is the Arabidopsis receptor kinase FLAGELLIN SENSING 2 (FLS2), which specifically recognizes'a conserved 22 amino acid N-terminal sequence of Pseudomonas syringae pv . tomato DC3000 (Pst) flagellin protein (flg22). Although extensively studied in Arabidopsis, the functions of RLKs in crop plants remain largely uninvestigated. To understand the roles of RLKs in soybean (Glycine max), GnsFLS2 was silenced via virus induced gene silencing (VIGS) mediated by Bean pod mottle virus (BPMV). No significant morphological differences were observed between GmFLS2-silenced plants and the vector control plants. However, silencing GmFLS2 significantly enhanced the susceptibility of the soybean plants to Pseudomonas syringae pv . glycinea (Psg). Kinase activity assay showed that silencing GmFLS2 significantly reduced the phosphorylation level of GmMPK6 in response to flg22 treatment. However, reduced phosphorylation level of both GmMPK3 and GmMPK6 in response to Psg infection was observed in GmFLS2-silenced plants, implying that defense response is likely transduced through activation of the downstream GrnMAPK signaling pathway upon recognition of bacterial pathogen by GmFLS2. The core peptides of flg22 from Pst and Psg were highly conserved and only 4 amino acid differences were seen at their N-termini. Interestingly, it appeared that the Psg-flg22 was more effective in activating soybean MAPKs than activating Arabidopsis MAPKs, and conversely, Pst-fig22 was more effective in activating Arabidopsis MAPKs than activating soybean MAPKs, suggesting that the cognate recognition is more potent than heterologous recognition in activating downstream signaling. Taken together, our results suggest that the function of FLS2 is conserved in immunity against bacteria pathogens across different plant species.
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  • High-Level Expression, Purification and Large-Scale Production of l-Methionine gamma-Lyase from Idiomarina as a Novel Anti-Leukemic Drug.

    Huang, Kui-Ying   Hu, Hai-Yan   Tang, Yan-Lai   Xia, Feng-Geng   Luo, Xue-Qun   Liu, Jian-Zhong  

    l-Methionine gamma-lyase (MGL), a pyridoxal 5'-phosphate-dependent enzyme, possesses anti-tumor activity. However, the low activity of MGL blocks the anti-tumor effect. This study describes an efficient production process for the recombinant MGL (rMGL) from Idiomarina constructed using the overexpression plasmid in Escherichia coli BL21 (DE3), purification, and large-scale production. The enzyme produced by the transformants accounted for 53% of the total proteins and accumulated at 1.95 mg/mL using a 500 L fermentor. The enzyme was purified to approximately 99% purity using a high-pressure mechanical homogenizer and nickel (Ni) Sepharose 6 Fast Flow (FF) chromatography. Then, the enzyme was polished by gel filtration, the endotoxins were removed using diethyl-aminoethanol (DEAE) Sepharose FF, and the final product was lyophilized with a vacuum freeze dryer at -35 =C2=B0C. The specific activity of rMGL in the lyophilized powder was up to 108 U/mg. Compared to the control, the enzyme significantly inhibited cellular proliferation in a concentration-dependent manner as tested using the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay and induced cellular apoptosis as analyzed by Annexin V-fluorescein isothiocyanate (FITC) with fluorescence-activated cell sorting (FACS) in leukemia cells. This paper demonstrated the cloning, overexpression, and large-scale production protocols for rMGL, which enabled rMGL to be used as a novel anti-leukemic drug. =20
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  • Overexpression of a soybean nuclear localized type-III DnaJ domain-containing HSP40 reveals its roles in cell death and disease resistance

    Liu, Jian-Zhong   Whitham, Steven A.  

    Heat-shock proteins such as HSP70 and HSP90 are important molecular chaperones that play critical roles in biotic and abiotic stress responses; however, the involvement of their co-chaperones in stress biology remains largely uninvestigated. In a screen for candidate genes stimulating cell death in Glycine max (soybean), we transiently overexpressed full-length cDNAs of soybean genes that are highly induced during soybean rust infection in Nicotiana benthamiana leaves. Overexpression of a type-III DnaJ domain-containing HSP40 (GmHSP40.1), a co-chaperone of HSP70, caused hypersensitive response (HR)-like cell death. The HR-like cell death was dependent on MAPKKK and WIPK, because silencing each of these genes suppressed the HR. Consistent with the presence of a nuclear localization signal (NLS) motif within the GmHSP40.1 coding sequence, GFP-GmHSP40.1 was exclusively present in nuclear bodies or speckles. Nuclear localization of GmHSP40.1 was necessary for its function, because deletion of the NLS or addition of a nuclear export signal abolished its HR-inducing ability. GmHSP40.1 co-localized with HcRed-SE, a protein involved in pri-miRNA processing, which has been shown to be co-localized with SR33-YFP, a protein involved in pre-mRNA splicing, suggesting a possible role for GmHSP40.1 in mRNA splicing or miRNA processing, and a link between these processes and cell death. Silencing GmHSP40.1 enhanced the susceptibility of soybean plants to Soybean mosaic virus, confirming its positive role in pathogen defense. Together, the results demonstrate a critical role of a nuclear-localized DnaJ domain-containing GmHSP40.1 in cell death and disease resistance in soybean.
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  • Drought tolerance of nitric oxide associated 1 mutant of Arabidopsis is mostly due to its reduced transpiration as a result of smaller stature

    Xu, Wei   Zhang, Shuangshuang   Wang, Da-Li   Liu, Jian-Zhong  

    Arabidopsis noa1 mutant has a small stature and is more resistant to water deficit than wild-type Col-0. To investigate whether the size of noa1 plays a role in drought tolerance, Col-0, noa1 as well as gsnor1-3 and a transgenic line over-expressing a DnaJ domain Hsp40 from soybean (GmHSP40ox), all of which have smaller statures than Col-0, were subjected to drought treatment. Our results showed that the genotypes with smaller statures survived longer than Col-0 under drought conditions when grown in separate containers, which is correlated with the reduced net water losses of plants and the higher water content in the soil during the drought stress treatment. However, when randomly grown in the same containers, the plants of the four genotypes dried out almost at the same time, indicating that the reduced transpirations due to the smaller sizes of the mutant plants might account for the prolonged surviving under drought in separate containers. In the same-container experiment, the accelerated water loss caused by the transpiration of Col-0 plants most likely contributed to the earlier dry-out of the three genotypes with smaller statures because a certain amount of the transpired water through Col-0 could have been used by noa1 gsnor1-3 or GmHSP40ox if grown in separate pots. Interestingly, noa1 had less stomata densities and the stomatal closures of both noa1 and gsnor1-3 were more sensitive to ABA. In addition, noa1 was more resistant to osmotic stress than both Col-0 and gsnor1-3. To our surprise, the water loss rates of detached leaves of both noa1 and gsnor1-3 were greater than that of Col-0, suggesting that the water loss rates of detached leaves may not represent that of in planta leaves. Together, our results suggest that (1) plant sizes of different genotypes must be taken into consideration in evaluating drought trait, and multiple approaches and criteria are needed to ensure the accurate evaluation of drought tolerance; (2) when investigated genotypes have big differences in statures, both the same-container and the separate-container experiments are necessary for screening the resistant or tolerant genotypes; when the investigated genotypes have comparable statures, the separate-container experiment is more relevant; (3) the increased drought tolerance of noa1 is resulted from combined effects of the smaller stature, the increased sensitivity of stomata closure to ABA and the enhanced resistance to osmotic stress; and (4) water loss rate of detached leaves is not a good indicator in evaluating drought tolerance.
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  • Phosphohexose mutase of Xanthomonas oryzae pv. oryzicola is negatively regulated by HrpG and HrpX, and required for the full virulence in rice

    Guo, Wei   Chu, Cong   Yang, Xiao-Xia   Fang, Yuan   Liu, Xia   Liu, Jian-Zhong  

    The genome of Xanthomonas oryzae pv. oryzicola annotates one uncharacterized gene, XOC_3841, only one ORF in this strain is annotated to encode Phosphohexose mutase (XanA), which reversibly converts glucose 1-phosphate to glucose 6-phosphate that implicates in the carbon metabolism pathways. However, it is unclear whether the XanA-coding gene is involved in the full virulence of X. oryzae pv. oryzicola. In this report, we showed that the mutagenesis in unique xanA, led the pathogen effectively to unable to utilize glucose and galactose for growth. The expression of xanA was strongly induced by glucose, sucrose, fructose, mannose or galactose at least 3 times higher than that by non-sugar NY medium. Intriguingly, xanA promoter region contains an imperfect PIP-box (plant-inducible promoter) (TTCGC-N16-TTCGA), and the expression of xanA was inducible in rice suspension cells rather than in a nutrient-rich (NB) medium and negatively regulated by a key hrp regulatory HrpG and HrpX cascade. More importantly, mutation in xanA resulted in impairment of bacterial growth and virulence in planta, and reduced bacterial cell motility and extracellular polysaccharides (EPS) production in media. In addition, the lost properties mentioned above in R Delta xanA were completely restored to the wild-type level by the presence of xanA in trans. All these results suggest that xanA is required for EPS production, cell motility and the full virulence of X. oryzae pv. oryzicola.
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  • Fractal characteristics of pore structures in 13 coal specimens:Relationship among fractal dimension,pore structure parameter,and slurry ability of coal

    Zhu, Jie-Feng   Liu, Jian-Zhong   Yang, Yu-Meng   Cheng, Jun   Zhou, Jun-Hu   Cen, Ke-Fa  

    The fractal characteristics of pore structures in 13 different coal specimens were investigated. Insights into the relationship among fractal dimension, pore structure parameter, and slurry ability of coal were provided. N-2 adsorption/desorption at 77 K was applied to analyze the pore structure of coal. Two fractal dimensions, D-1 and D-2, at relative pressures of 0 to 0.45 and 0.45 to 1, respectively, were calculated with the fractal Frenkel-Halsey-Hill model. Results reveal that the value of D-1 is mainly affected by the influence of meso- and macro-pores with an average pore size range of 10 nm to 220 nm on the specific surface area; therefore, Di can be utilized to quantitatively describe the surface roughness of these meso- and macro-pores in coal. Meanwhile, the value of D-2 is mainly related to the effects of fine mesopores with an average pore size range of 2 nm to 10 nm on the total pore volume; therefore, D-2 can be utilized to quantitatively describe the volumetric roughness of these mesopores in coal. Di has no apparent linear correlation with the pore structure parameters and maximum solid loading of coal, and D-2 has a positive linear correlation with the specific surface area and total pore volume of coal. The increase in specific surface area, total pore volume, and D-1 has negative effects on the slurry ability of coal. High-rank coals with high ash content and low volatile matter relatively have higher Di and lower D-2. Meanwhile, with increasing coal rank, D-2 has a decreased trend. The fine mesopores with an average pore size range of 2 nm to 10 nm in coal have direct effects on the pore structure parameters and D-2 of coal; thus, the slurry ability of coal may be improved if the number of these mesopores in coal is reduced by modification processes, such as microwave irradiation, hydrothermal treatment and so on. (C) 2016 Elsevier B.V. All rights reserved.
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