Under the background of the energy saving and emission reduction, more and more attention has been placed on investigating the energy efficiency of ships. The added resistance has been noted for being crucial in predi...Under the background of the energy saving and emission reduction, more and more attention has been placed on investigating the energy efficiency of ships. The added resistance has been noted for being crucial in predicting the decrease of speed on a ship operating at sea. Furthermore, it is also significant to investigate the added resistance for a ship functioning in short waves of large modern ships. The researcher presents an estimation formula for the calculation of an added resistance study in short waves derived from the reflection law. An improved method has been proposed to calculate the added resistance due to ship motions, which applies the radiated energy theory along with the strip method. This procedure is based on an extended integral equation （EIE） method, which was used for solving the hydrodynamic coefficients without effects of the irregular frequency. Next, a combined method was recommended for the estimation of added resistance for a ship in the whole wave length range. The comparison data with other experiments indicate the method presented in the paper provides satisfactory results for large blunt ship.展开更多
In order to understand the interaction between ethylene-induced esterase（EIE, EC 3.1.1.） from Citrus sinensis and α-naphthyl acetate, a3D model of EIE was generated based on the crystal structure of the tobacco sal...In order to understand the interaction between ethylene-induced esterase（EIE, EC 3.1.1.） from Citrus sinensis and α-naphthyl acetate, a3D model of EIE was generated based on the crystal structure of the tobacco salicylic acid binding protein 2（SABP2）. With the aid of the molecular mechanics and molecular dynamics methods, the final refined model was obtained and its reliability was further assessed. In this study, the docking results show that the main-chain amide of residue His85 and residue Vall8 can form hydrogen bonds to the carbonyl oxygen group of α-naphthyl acetate. MM-PBSA method was applied to calculating the binding free energy between EIE mutants and α-naphthyl acetate. Our calculated binding free energy of each of the two mutant complexes is increased compared with that of the one of the wild type, which is unfavorable to the reaction. It is well consistent with the experimental data. The above results clearly indicate that His85 and Vail8 in EIE function as the oxyanion role and take part in the catalytic reaction. The new structural insights obtained from this computational study are expected to stimulate further biochemical studies on the structures and mechanisms of EIE and other members of the plant α/β hydrolases.展开更多
淡水水生生物的分布模式一直是进化和生物地理学研究中的热点问题,特别是对具休眠体水生生物的研究,早在达尔文时代就开始探讨具休眠体淡水水生生物分布的原因。根据对文献的整理,可以将具休眠体淡水水生生物分布模式归纳为三种假说:随...淡水水生生物的分布模式一直是进化和生物地理学研究中的热点问题,特别是对具休眠体水生生物的研究,早在达尔文时代就开始探讨具休眠体淡水水生生物分布的原因。根据对文献的整理,可以将具休眠体淡水水生生物分布模式归纳为三种假说:随机分布(Everything is Everywhere,EIE)假说、独占(Monopolisation)假说和局域特有(Moderate Endemicity,ME)假说。通过对三种假说的定义,研究进展和形成不同模式的原因等进行分析,提出了在研究时需注意是否存在隐存种、季节变化引起基因型变化、研究区域是否覆盖了本物种的所有分布范围、地理环境及地质事件与分布模式之间的关系等问题,以便更准确的研究具休眠体淡水水生生物分布模式。展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.51079032 the Outstanding Youth Science Foundation of Heilongjiang Province,No.200908
文摘Under the background of the energy saving and emission reduction, more and more attention has been placed on investigating the energy efficiency of ships. The added resistance has been noted for being crucial in predicting the decrease of speed on a ship operating at sea. Furthermore, it is also significant to investigate the added resistance for a ship functioning in short waves of large modern ships. The researcher presents an estimation formula for the calculation of an added resistance study in short waves derived from the reflection law. An improved method has been proposed to calculate the added resistance due to ship motions, which applies the radiated energy theory along with the strip method. This procedure is based on an extended integral equation （EIE） method, which was used for solving the hydrodynamic coefficients without effects of the irregular frequency. Next, a combined method was recommended for the estimation of added resistance for a ship in the whole wave length range. The comparison data with other experiments indicate the method presented in the paper provides satisfactory results for large blunt ship.
基金Supported by the Basic Research Fund of Jilin University, China(No.200810019)
文摘In order to understand the interaction between ethylene-induced esterase（EIE, EC 3.1.1.） from Citrus sinensis and α-naphthyl acetate, a3D model of EIE was generated based on the crystal structure of the tobacco salicylic acid binding protein 2（SABP2）. With the aid of the molecular mechanics and molecular dynamics methods, the final refined model was obtained and its reliability was further assessed. In this study, the docking results show that the main-chain amide of residue His85 and residue Vall8 can form hydrogen bonds to the carbonyl oxygen group of α-naphthyl acetate. MM-PBSA method was applied to calculating the binding free energy between EIE mutants and α-naphthyl acetate. Our calculated binding free energy of each of the two mutant complexes is increased compared with that of the one of the wild type, which is unfavorable to the reaction. It is well consistent with the experimental data. The above results clearly indicate that His85 and Vail8 in EIE function as the oxyanion role and take part in the catalytic reaction. The new structural insights obtained from this computational study are expected to stimulate further biochemical studies on the structures and mechanisms of EIE and other members of the plant α/β hydrolases.
文摘淡水水生生物的分布模式一直是进化和生物地理学研究中的热点问题,特别是对具休眠体水生生物的研究,早在达尔文时代就开始探讨具休眠体淡水水生生物分布的原因。根据对文献的整理,可以将具休眠体淡水水生生物分布模式归纳为三种假说:随机分布(Everything is Everywhere,EIE)假说、独占(Monopolisation)假说和局域特有(Moderate Endemicity,ME)假说。通过对三种假说的定义,研究进展和形成不同模式的原因等进行分析,提出了在研究时需注意是否存在隐存种、季节变化引起基因型变化、研究区域是否覆盖了本物种的所有分布范围、地理环境及地质事件与分布模式之间的关系等问题,以便更准确的研究具休眠体淡水水生生物分布模式。
