Xuzhou Institute of Technology

About: Xuzhou Institute of Technology is a education organization based out in Xuzhou, China. It is known for research contribution in the topics: Catalysis & Computer science. The organization has 1696 authors who have published 1521 publications receiving 13541 citations.

QM/MM studies on the calcium‐assisted β‐elimination mechanism of pectate lyase from bacillus subtilis

Abstract: Pectate lyase utilizes the anti-β-elimination chemistry to catalyze the cleavage of α-1,4 glycosidic bond between D -galacturonate regions during the degradation of plant polysaccharide pectin. We report here detailed mechanistic studies of the Bacillus subtilis pectate lyase (BsPel) using QM/MM calculations. It was found that the residue Arg279 serves as the catalytic base to abstract the α-proton from C52 atom of substrate Ada2 subsite, forming an unstable carbanion intermediate. The glycosidic bond of this intermediate is scissile to generate the 4,5-unsaturated digalacturonate product and a negatively charged β-leaving group. Two active site residues (Lys247 and Arg279) and two Ca2+ ions (Ca2 and Ca3) form hydrogen-bonding and coordination interactions with C52 COO- of Ada2, respectively, which facilitate the proton abstraction and stabilize the generated carbanion intermediates. Arg284 is not the potential proton donor to saturate the leaving group. Actually, the proton source of leaving group is the solvent water molecule rather than any active site acidic residues. In addition, the calculation results suggest that careful selections of QM- and Active-regions are essential to accurately explore the enzymatic reactions. Proteins 2016; 84:1606-1615. © 2016 Wiley Periodicals, Inc.

Effect of Ferrite Grain Size on the Yield-Strength Ratio of Low-Carbon Alloy Steel

Abstract: Using thermo-mechanical controlled process, the experiment on the yield-strength ratio of low-carbon alloy steel was carried out and the effect of ferrite grain size on the yield-strength ratio of steel was discussed. Theory analysis and the experimental results indicate that the smaller ferrite grain size is, the higher the yield-strength ratio is. In addition, the regression formulas on yield and tensile strength are also obtained.

Improved efficiency of single-component active layer photovoltaics by optimizing conjugated diblock copolymers

Abstract: The synthesis of single-component, all-conjugated D–A diblock copolymers that exhibit high photovoltaic activity remains a significant challenge. To date, the synthesis of all-conjugated block copolymers typically produces a mixture of donor and acceptor homopolymers, diblock copolymers, ternary block copolymers or multi-block copolymers. In this work, we report the use of an A–B type monomer to synthesise a diblock copolymer. Importantly, by avoiding AA + BB polymerization, we have eliminated the production of ternary block and multi-block copolymers. In addition, the donor and acceptor blocks had orthogonal solubility in order to increase the purity of the block copolymer and give significant nanoscale phase separation. Two single-component diblock copolymers (P3HT-b-TBTF8 and P3HT-b-F8TBT) were synthesized, of which different molecular weights were obtained using Soxhlet extraction and preparative GPC. Both copolymers exhibited good thermal stability and effective self-aggregation. Thermal annealing was found to reduce the self-aggregation time and enhance the crystallization of the P3HT block, which effectively reduced the self-aggregation of the polymers. The power conversion efficiency of a single component active layer based P3HT-b-F8TBT photovoltaic device reached 1.22%. The higher efficiency of this device was thought to be caused by the linkage between the donor and acceptor blocks, whose P3HT and PF8TBT chains are separated by the wider bandgap F8 unit. Moreover, the unique molecular structure and self-assembly properties of these diblock copolymers will allow them to be used as model materials for further studies on charge and energy transfer in photovoltaic devices.

Optimization of plasma sprayed tungsten coating on copper with the heterogeneous compliant layer for fusion application

Abstract: Structure of 1-mm tungsten (W) coating on copper (Cu) with the different compliant layers was designed and optimized by means of ANSYS code Three materials of titanium, nickel-chromium-aluminum alloys, and W/Cu mixtures with a thickness of 05 mm were selected as the compliant layers to evaluate their effects on the interface stress between W and Cu, strain, and the surface temperature under the heat load of 5 MW/m2 Application of the compliant layers can obviously alleviate the interface stress concentration compared to the sharp interface The maximum stress reduction of about 25% was obtained from the W/Cu-compliant layer; however, the surface temperature was increased only by 12 °C Further investigation on the W/Cu-compliant layer revealed that 01-02-mm 20-35 vol% W was the optimum structure for 1-mm W coating, which resulted in the smallest peak stress of 299 MPa and the equivalent plastic strain of 001%

Enzymatic Extraction of Inulin from Burdock (Arctium lappa L.) Root

Abstract: Inulin was extracted by using enzyme hydrolysis method from burdock (Arctium lappa L.) root. The optimum extraction conditions were as follows: neutral protease content 13.5 g/100 mL, pH 7, solid/liquid ratio 1:15, hydrolysis time 6 h, temperature 50 ℃. The yield of inulin under the optimum conditions was 14.57%. A 2.5 g/100 mL solution of chitosan in 1% aqueous acetic acid was prepared which contained 7.5 mg/ml of neutral protease, and then it was poured, dropwise, into a suspension medium consisting of 40% formaldehyde and 2 mol/L of NaOH at the volume ratio of 2:3 at 60℃ and pH 7.5. The immobilization time was 8 h. And the recovery of enzyme activity was 39.13%. The optimum extraction conditions using immobilized enzyme were as follows: pH 7, solid/liquid ratio 1:15, hydrolysis temperature 60 ℃, immobilized enzyme 13.5 g/100 mL. Under such conditions ,the yield of inulin was 12.89%. After 10 times continuous reaction, the yield of inulin decreased to 9.42%, which indicated that the stability of the immobilized enzyme was significantly improved.