关键词：
binding affinity;intermediate state;kinesin;molecular dynamics simulation;one-head-bound state
摘要：
Kinesin dimer walks processively along a microtubule (MT) protofilament in a hand-over-hand manner, transiting alternately between one-head-bound (1HB) and two-heads-bound (2HB) states. In 1HB state, one head bound by adenosine diphosphate (ADP) is detached from MT and the other head is bound to MT. Here, using all-atom molecular dynamics simulations we determined the position and orientation of the detached ADP-head relative to the MT-bound head in 1HB state. We showed that in 1HB state when the MT-bound head is in ADP or nucleotide-free state, with its neck linker being undocked, the detached ADP-head and the MT-bound head have the high binding energy, and after adenosine triphosphate (ATP) binds to the MT-bound head, with its neck linker being docked, the binding energy between the two heads is reduced greatly. These results reveal how the kinesin dimer retains 1HB state before ATP binding and how the dimer transits from 1HB to 2HB state after ATP binding. Key residues involved in the head-head interaction in 1HB state were identified.
摘要：
We describe the synthesis of a series of novel nitrogen- and phosphorus-enriched biochar (activated carbon, AC) nanocomposites via the co-pyrolysis of Camellia oleifera shells (COSs) with different weight ratios of ammonium polyphosphate (APP) (w(APP): w(COSs)=1-3:1). The physicochemical characteristics of these nanocomposites (APP@ACs) were investigated via X-ray diffraction (XRD), Raman spectroscopy, N(2) adsorption/desorption analysis, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). The results revealed that the APP@ACs exhibited richer N- and P-containing functional groups than unmodified AC. In addition, the removal performance of APP@AC-3 with respect to Pb(II) (723.6mgg(-1)) was greatly improved relative to unmodified AC (264.2mgg(-1)). Kinetic and equilibrium data followed the pseudo-second-order kinetic model and Langmuir model, respectively. The removal mechanism could be attributed to partial physisorption and predominant chemisorption. The N(2) adsorption/desorption isotherms demonstrated that pore-volume properties could be an effective physical trap for Pb(II). Furthermore, the XPS and FTIR analysis revealed that the chemical removal mechanism of the APP@ACs is surface complexation via N-containing and P-containing functional groups. These findings indicate that the co-pyrolysis of COSs and APP leads to the formation of nitrogen- and phosphorus-containing functional groups that facilitate excellent activated carbon-based (biochar) adsorption performance.
期刊：
Nanoscience and Nanotechnology Letters,2019年11(10):1387-1394 ISSN：1941-4900
通讯作者：
Chen, Hong
作者机构：
[He, Haiying; Fan, Touwen; Chen, Hong; Wu, Zibin; Yang, Zhihao; Chen, Yu] Foshan Univ, Sch Mat Sci & Energy Engn, Foshan 528000, Guangdong, Peoples R China.;[Chen, Hong] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Hunan, Peoples R China.;[Yu, Minghuai] Hainan Univ, Sch Sci, Haikou 570228, Hainan, Peoples R China.
通讯机构：
[Chen, Hong] F;[Chen, Hong] C;Foshan Univ, Sch Mat Sci & Energy Engn, Foshan 528000, Guangdong, Peoples R China.;Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Hunan, Peoples R China.
关键词：
SnO2;First-Principles Calculation;Electronic Structure;Dielectric Function
摘要：
First-principles calculation based on density functional theory (DFT) were employed to theoretically study the influence of partially replacing Sn4+ by Mg2+ on the electronic structure and optical properties of SnO2. The calculation results revealed that the Femi level shifted into the valence band, thereby indicating a p-type conductivity character. The energy band gap for SnO2 was found to be narrowed due to Mg2+ doping. Considering that the energy level for Mg 3s orbitals is comparable to that of O 2p orbitals, the localization behavior in the SnO2 valence band was modified. The imaginary part of dielectric functions' spectrum shifted towards lower energy after doping SnO2 with Mg2+, accompanied by an obvious redshift of the absorption edge. Furthermore, the absorption intensity for the doped systems was larger than that of pure SnO2 matrix in the low-energy region.
摘要：
<jats:title>Abstract</jats:title><jats:p>Inorganic compounds, including graphite, transition metal oxides, and chalcogenides, are widely used as electrode materials in rechargeable lithium‐ion batteries (LIBs). However, environmentally friendly and cost‐effective alternatives are pursued by focusing on the molecular design of organic materials that could be potential electrode materials in next‐generation LIBs. Herein, we study the utilization of an organic compound, azobenzene 4,4‐dicarboxylate lithium (ADL), as a negative electrode in full‐cell LIBs. The full‐cell LIBs are assembled by using ADL as the negative electrode, LiCoO<jats:sub>2</jats:sub> (LCO/ADL) or LiFePO<jats:sub>4</jats:sub> (LFP/ADL) as the positive electrode, and 1 M LiPF<jats:sub>6</jats:sub> dissolved in ethylene carbonate/diethylene carbonate (EC : DEC=1 : 1 by volume) as the electrolyte. Then, ex situ X‐ray diffraction (XRD), ex situ X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were carried out to understand the charge storage mechanism and structural changes during the electrochemical reaction. From the charge/discharge measurements, LFP/ADL rendered a higher specific capacity retention (88.05 %) than LCO/ADL full‐cells (73.79 %) after 200 cycles at a current density of 100 mA g<jats:sup>−1</jats:sup>. The XPS analysis revealed that the deposition of metallic Li on the ADL anode in LCO/ADL full‐cells led to rapid capacity decay and inferior cyclic performance, whereas Li‐free metal deposition had been observed on the ADL anode in LFP/ADL full cells, which explained the higher cyclic stability and capacity retention rate in LFP/ADL full‐cells. The present study provides useful insights into the development and practical utilization of organic electrodes in next‐generation Li‐ion battery technology.</jats:p>
摘要：
Changes of affinity of kinesin head to microtubule regulated by changes in the nucleotide state are essential to processive movement of kinesin on microtubule. Here, using all-atom molecular dynamics simulations we show that besides the nucleotide state, large conformational changes of microtubule-tubulin heterodimers induced by strong interaction with the head in strongly binding state are also indispensable to regulate the affinity of the head to the tubulin. In strongly binding state the high affinity of the head to microtubule arises largely from mutual conformational changes of the microtubule and head induced by the specific interaction between them via an induced-fit mechanism. Moreover, the ADP-head has a much weaker affinity to the local microtubule-tubulin, whose conformation is largely altered by the interaction with the head in strongly binding state, than to other unperturbed tubulins. This indicates that upon Pi release the ADP-head temporarily has a much weaker affinity to the local tubulin than to other tubulins.
摘要：
LiFe1-x(Ni0.98Co0.01Mn0.01)(x)PO4/C (x = 0.01, 0.03, 0.05, 0.07) is prepared by using spent electroless nickel plating solution as a raw material. The mechanism of the reaction is investigated by the analyses of thermogravimetric and differential scanning calorimeter (TG/DSC) and X-ray diffraction (XRD). It is found that the formation of LiFe1-x(Ni0.98Co0.01Mn0.01)(x)PO4/C starts at 300 degrees C, and above 500 degrees C, the product can be ascribed to LiFe1-x(Ni0.98Co0.01Mn0.01)(x)PO4/C. The structure, morphology and electrochemical properties of the samples are characterized by XRD, scanning electron microscope (SEM), electrochemical impedance spectroscopy(EIS) and charge/discharge tests. The results show that the Ni, Co and Mn multi-doping does not destroy the olivine structure of LiFePO4 and is beneficial to the uniform distribution of particles, which improves the electrochemical properties of the samples. Especially, LiFe0.97(Ni0.98Co0.01Mn0.01)(0.03)PO4/C exhibits the best cycling stability and rate capability among all the samples. Its initial discharge capacity is 150.6 mAh g(-1) with the capacity retention of 98.8% after 100 cycles at 1 C. Even at 10 C, it still shows a high discharge capacity of 116.5 mAh g(-1). (C) 2015 Elsevier Ltd. All rights reserved.
期刊：
Journal of Pure and Applied Microbiology,2015年9(Special Edition 1):307-311 ISSN：0973-7510
通讯作者：
Peng, W.
作者机构：
[Lin Z.; Chen H.] School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, China;Laboratory of Biomaterials Science, Kyoto Prefectural University, Kyoto, Japan;[Wu J.] Xuzhou Feiya Wood Industry Co. Ltd, Xuzhou, China;[Peng W.] School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, China<&wdkj&>Laboratory of Biomaterials Science, Kyoto Prefectural University, Kyoto, Japan
通讯机构：
School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, China
关键词：
cellulose;formaldehyde;hemicellulose;lignin;Article;carbon nuclear magnetic resonance;etherification;Eucalyptus;high resolution melting analysis;infrared spectroscopy;nonhuman;oxidation;public health
作者机构：
[Wang, Li; He, Xiangming; Shang, Yuming; Cao, Jiang] Tsinghua Univ, Inst Nucl & New Energy Technol, Beijing 100084, Peoples R China.;[Chen, Hong; Cao, Jiang] Ctr South Univ, State Key Lab Powder Met, Changsha 410083, Hunan, Peoples R China.;[He, Xiangming] Tsinghua Univ, State Key Lab Automot Safety & Energy, Beijing 100084, Peoples R China.;[Deng, Lingfeng; Chen, Hong] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Wang, Li] T;Tsinghua Univ, Inst Nucl & New Energy Technol, Beijing 100084, Peoples R China.
摘要：
In this work, we report novel composite electrospun membranes for Li-ion batteries. A monodispersed nano-sized TiO2@Li+ single ionic conductor containing a P(AALi-MMA) polymer layer grafted on a nano-sized TiO2 surface was prepared and used as functional fillers in composite membranes. The obtained results show that our material, based on the incorporation of a nano-sized TiO2@Li+ single ionic conductor into a composite electrospun membrane is a new generation battery separator for application in lithium-ion batteries.
作者机构：
[Zhang, Jianxiong; Chen, Hongbin; Luo, Yongfeng; Li, Xi; Liao, Chunrong] Cent South Univ Forestry & Technol, Coll Sci, Changsha 410004, Hunan, Peoples R China.;[Li, Xianjun] Cent South Univ Forestry & Technol, Mat Sci & Engn Sch, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Luo, Yongfeng] C;Cent South Univ Forestry & Technol, Coll Sci, Changsha 410004, Hunan, Peoples R China.
关键词：
Energy efficiency;Microwave pretreatment;Rectangular resonant cavity;Temperature distribution;Wood
摘要：
Wood pretreated by high-intensity microwaves was theoretically studied based on the Maxwell electromagnetic field equations and the heat and mass transfer mechanism of wood. The effects of feeding modes on the temperature field uniformity and energy efficiency were studied using the finite element method, and optimized parameters of the rectangular microwave resonant cavity were achieved. The results show that the feeding modes had a great effect on the temperature field uniformity of the wood and the energy efficiency. Compared to the side single-port, the upper single-port, and the upper-under port feeding modes, the two-side ports feeding mode was the best for temperature field uniformity and energy efficiency.
摘要：
A facile sol–gel method has been developed to create a superhydrophobic surface on aluminum substrate with tetraethylorthosilicate (TEOS) and vinyltriethoxysilane (VTES) as co-precursor at room temperature. Firstly, nanometer sized silica particles were self assembled on the substrate through the hydrolysis of TEOS. Then, the silica particles were modified with vinylsiloxane through the hydrolysis and condensation polymerization of VTES. The emphasis was focused on investigating the influence of the molar ratio between NH3·H2O and ethanol on the surface morphology and wetting property. The surface morphology was observed by scanning electron microscopy (SEM), the chemical composition and bonding state of the surface were explored by energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectra (XPS), and the wetting property of the surface was investigated by water contact angle measurement (WCA). The modified silica-based surface possessed the greatest static contact angle of 154.9°, exhibiting excellent superhydrophobic property. A hierarchical microstructure with spherical microparticles of around 2 μm decorated with nanoparticles of around 450 nm was observed on the film surface. The surface was covered by hydrophobic vinyl groups via the decoration of silica microparticles with vinyl-terminated siloxane nanoparticles as evidenced by EDS, FTIR and XPS. The corrosion resistant performance and durability of the superhydrophobic silica-based surface formed on aluminum substrate in corrosive NaCl solution were estimated by electrochemical impedance spectroscopy (EIS) measurements. The appropriate equivalent circuit model was put forward to fit and analyze the EIS data. The electrochemical result revealed that the corrosion resistant performance of aluminum was improved greatly by the superhydrophobic treatment.
