Electrochemical reduction of carbon dioxide with lead cathode and zinc anode in dry acetonitrile solution

The electrochemical reduction of carbon dioxide (CO₂) is investigated in acetonitrile with tetrabutylammonium perchlorate as an electrolyte using a lead cathode and a sacrificial zinc anode, and the product under such a setup is insoluble zinc oxalate at potentials between ?2.2 and ?2.8 V vs. Ag rod electrode. Preelectrolysis is an effective method to remove the water in the electrolyte, which makes a distinct reduction peak of CO₂ appear at ?2.6 V vs. Ag on cyclic voltammogram. Even trace amounts of water in the electrolyte can interfere with the faradaic efficiency of reduction of CO₂ to oxalate, and the product could be β-ZnC₂O₄ (in anhydrous solution) or ZnC₂O₄?·?2H₂O (if water exists). The faradaic efficiency for oxalate production also depends on the cathode potential and the temperature, and the maximum is 96.8 % at ?2.6 V vs. Ag and 5 °C. This is the highest value of CO₂ electrochemical reduction found in the literature under ambient pressure.     

Asymmetric Aziridination by Reaction of Chiral Sulfinimine Derived From (+)-Camphor with Dimethyloxosulfonium Methylide

Addition of dimethyloxosulfonium methylide to chiral nonracemic pure (+)-camphor-derived sulfinimine I affords N-sulfinyl aziridine. which are easily separated The N-(+)-camphor-based-sulfinyl auxiliary was removed without ring opening by treatment with MeLi.     

Point-based integration for 3D object reconstruction from Ladar range images

A method of point-based integration from multiple registered laser radar (Ladar) range images for 3D object reconstruction is presented in this literature. Our method operates surface point data directly and provides a direct way for overlapping data removal. The overlapping areas were detected using a single distance threshold. In order to set the distance threshold, a local point density approach is introduced to solve it. Compared with the mesh-based, volumetric and other points-based integration approaches, our method is simple and fast, and need less storage memory. The approach is performed on various objects with different geometric shapes. The experimental results demonstrate the efficiency and feasibility of our method.     

Suppressed molecular orientation in nylon 6/clay nanocomposite at large strain: Role of microvoiding

A micro‐FTIR measurement has been conducted to explore the molecular orientation of amorphous phase in the nylon 6/clay nanocomposite at large strain. Our results indicate that the molecular orientation in such a nanocomposite during stretching is lower than that observed for the pure nylon 6 counterpart, which is further evidenced by the true stress‐strain dependence. The relaxation of the molecular network, resulted from the destruction of γ‐crystals in part and mostly from microvoding (demonstrated by volume dilatation and 2D‐SAXS measurements), should be responsible for the suppressed molecular orientation in the nylon 6/clay nanocomposite. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 514–519, 2010     

惯性辅助超短基线GPS航姿解算

ＧＰＳ航姿系统是利用ＧＰＳ 载波相位相对测量来确定载体的航向和姿态。对于只有２ ～３ 个载波波长的超短基线，载波相位初始模糊度的确定将变得容易，而且这样的超短基线有利于周跳的检测，但超短基线使航姿解算精度较低。为了提高航姿解算的精度和可靠性，本文提出了ＧＰＳ航姿和低精度陀螺的组合系统，并进行了仿真研究。     

Pyridine-keggin heteropoly compounds as catalyst for hydroxylation of phenol using hydrogen peroxide as oxidant

The pyridine-heteropoly compounds are very active catalysts for phenol hydroxylation to dihydroxybenzenes with hydrogen peroxide as oxidant in aqueous solutions. The conversion of phenol reaches 77.8%, and the selectivity for dihydroxybenzenes reaches 99%.     

Elemental distributions in rat olfactory bulbs after exposure to MnCl<Subscript>2</Subscript> measured by synchrotron radiation X-ray fluorescence

In this work, elemental distributions in the rat olfactory bulbs (OB) were measured by synchrotron radiation X-ray fluorescence (SRXRF) 9 hours after unilateral intranaris application of MnCl₂ solution. The effects of deposition of exogenous Mn in the OB on the distributions of other elements, particularly calcium, were also investigated. The results show that the application of MnCl₂ solution in the nasal cavity resulted in inhomogeneous deposition of Mn in the OB, with the highest Mn content found in the ipsilateral glomerular layer (GL). Locations in the ipsilateral hemisphere of the OB with higher Mn content were found to be associated with significantly higher calcium and zinc contents, suggesting the presence of excess exogenous Mn may affect the homeostasis of other trace elements such as calcium and zinc.     

Dynamic mechanical behavior of oriented semicrystalline polyethylene terephthalate

The dynamic mechanical behavior of molecularly oriented semicrystalline polyethylene terephthalate (PET) induced via the equal‐channel angular extrusion (ECAE) process was investigated. Dynamic mechanical analyses in both torsional mode and bending mode were utilized. The results indicate that the ECAE‐oriented PET has a higher dynamic storage modulus above the glass‐transition temperature than that of the reference (control sample). The combined effect of molecular orientation and crystallinity is responsible for the changes in the primary and secondary relaxations of PET. Further analyses show that the shifting and broadening of the primary and secondary peak positions in oriented PET are mainly due to the amorphous‐phase orientation because the crystallinity of PET decreases upon the ECAE processing. A good correlation was found between the structural anisotropy and the dynamic mechanical properties. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1394–1403, 2001