No abstract

Metal ion affinity chromatography is widely used to purify peptides on the basis of the dissimilarities of their amino acids. However, researchers are interested in the separation differences between different metal ions in this method. In our study, four kinds of commonly used metal ions are compared by the amount of immobilized metal ion on iminodiacetic acid-Sepharose and binding amount of soybean peptide to immobilized iminodiacetic acid-Mn(+) adsorbents and evaluated by high-performance liquid chromatography (HPLC) profiles. The results show that due to the different adsorption behaviors of metal ions, the binding ability order of soybean protein peptide on the column should be Fe(3+) > Cu(2+) > Zn(2+) > Ca(2+). The HPLC profiles show that peptides adsorbed by four kinds of metal ions display similar strong hydrophobic characteristics.

No abstract

Fast and deep debromination of polybrominated diphenyl ethers (PBDEs) under mild conditions is a challenge in the field of pollution control. A strategy was developed to achieve it by exploiting Cu/TiO composites as a noble-metal-free catalyst. Toward the debromination of 2,2',4,4'-tetrabromodiphenyl ether (BDE47) as a typical PBDE, the use of Cu/TiO as a catalyst and hydrazine hydrate (NH·HO) as a reducing agent yielded a degradation removal of 100% and a debromination efficiency of 87.7% in 3 s. A complete debromination of BDE47 at 1500 mg L was possible by successively adding NH·HO. A debromination pathway involving active H atom species was proposed for the catalytic transfer hydrogenation (CTH) of PBDEs according to the identified degradation intermediates. A mechanism was further clarified by density functional theory calculations: electrons are delivered from NH·HO to the metallic Cu atom via a coordination of N in NH·HO with Cu atoms. The electron-trapped Cu atom interacts with adsorbed BDE47 to form a transition complex, and then the debromination of this complex occurs on the surface of Cu nanoparticles due to the hydrogen donation of NH·HO through the CTH process. The new method provides a highly efficient method to remove brominated pollutants.

For the purpose of researching the displacement control system of heave compensation for offshore drilling platform, a set of crane type active and passive combined heave compensation device are designed on the basis of the similarity principle. As it known that platform heaving will be caused by the wind, sea wave and ocean current when conducting the drilling operations on the offshore drilling platform, which then will disturb the drilling operation. Therefore, the compensation device must be adopted to keep the vertical relative motion between the drill string system and the drilling platform to zero during the operation. Meanwhile, to improve the real-time performance of the heave compensation, the control system is optimized by establishing the simulation model of the active-passive combined crane, and LS-SVM(Least Squares Support Vector Machine) is improved by the artificial immune algorithm to predict the motion trend of offshore platforms. Eventually, in order to acquire the best control scheme, the Proportion Integration Differentiation (PID), fuzzy PID, BP neural network PID control method are utilized to carry out the simulation analysis, and the BP neural network PID control is found to be the optimum. Experiments showed that after using the BP neural network PID control algorithm, the displacement compensation rate of hook for active-passive combined crane device is more than 90%, the performance of the heave compensation is better, and the control is in time. INDEX TERMS Heave compensation, least squares support vector machine, BP neural network, PID control. FIGURE 1. Schematic diagram of crane type active-passive combined heave compensation device.