Improved estimation of PM2.5 brown carbon contributions to filter light attenuation

Multiwavelength light attenuation measurements have been acquired as part of thermal/optical carbon analysis in the U.S.Chemical Speciation Network(CSN)and the ...     

Copper(II)–lanthanide(III) 15-metallacrown-5 complexes based on pyrazinohydroxamic acid as new multiple-binding pentagonal platforms with Lewis amphoteric nature

Reaction of copper(II) acetate, lanthanium(III) or gadolinium(III) nitrate (1/5 equiv.) with pyrazinohydroxamic acid (H₂Pyzha) in DMF led to a series of new heterobimetallic 15-metallacrown-5 complexes. In a MeOH/H₂O solution the complexes exist as molecular unassociated metallacrowns. In solid state their structures are more complicated as it has been confirmed by X-ray analysis: discrete molecular metallacrowns [Gd(NO₃)₂{Cu(pyzha)}₅(DMF)₄(NO₃)] · 0.5C₆H₆ · H₂O (1), [Gd(NO₃)₂{Cu(pyzha)}₅(DMF)₅](NO₃) · 1.5DMF · 0.5H₂O (2), [La(NO₃)₂{Cu(pyzha)}₅(DMF)₅]NO₃ · 1.5DMF · 2C₆H₆ (3) are solvates, whereas compound [{La(NO₃)₂{Cu(pyzha)}₅(DMF)₅}₂(μ²-NO₃)](NO₃) · 3DMF (4) is a dimer, where μ-bridged nitrate links two copper centres of the adjacent metallamacrocycles. Complex [Gd(NO₃)₂{Cu(pyzha)}₅(DMF)₂(H₂O)(NO₃)] · CH₂Cl₂ · DMF (5) self-associates into a polymer chain by means of one pyrazine moiety and the copper ring atom. Reaction of the molecular metallacrowns with excess of inorganic salts CdBr₂ or Cu(OAc)₂ proceeds as anion methathesis process affording heteroanionic metallacrowns: molecular [Gd(NO₃)₂{Cu(pyzha)}₅(DMF)₅] [Gd(NO₃)₂{Cu(pyzha)}₅(DMF)₄(H₂O)][CdBr₄] · 1.5DMF (6), and 3D hydrogen bonded polymer [La(μ²-OAc)(H₂O)₃{Cu(pyzha)}₅ (H₂O)₄(NO₃)](NO₃) · 4H₂O (7).     

Er∶Yb∶YCOB晶体制备及其激光二极管抽运激光特性

研究了Er∶Yb∶YCa4O(BO3)3(简称Er∶Yb∶YCOB)的多晶制备和单晶生长,用提拉法生长出光学质量优良的Er∶Yb∶YCOB单晶,测量了其吸收光谱和荧光光谱,分析了其能级和泵浦原理,并进行了以激光二极管为抽运源的激光试验,实现了Er∶Yb∶YCOB晶体的在1.55μm附近110mW的激光输出,且斜效率达18.9;.     

Ultrasonic sensor to measure the density of a liquid or slurry during pipeline transport

This paper describes the design and testing of a computer-controlled sensor for the real-time measurement of the density of a liquid or slurry. It is to be deployed at the US Department of Energy's Hanford Site in Richland, WA, to monitor slurry properties during radioactive waste transfers. To demonstrate the sensor performance, tests were carried out using non-radioactive waste simulants and the results will be presented. The sensor is mounted flush with the pipeline wall in a nominal 5-cm (2-in.) pipe spool piece. The design pressure is 2.8 MPa (400 psi). The probe wedge in contact with the slurry was selected to operate up to pH 14, and the probe components were radiation tested at exposures of 1 x 10(6) R. The sensor is applicable for process control of all types of liquids or slurries in pipelines or in vessels.     

K-Theory for the Integer Heisenberg Groups

We give a closed formula for topological K-theory of the homogeneous space N/, where is the standard integer lattice in the simply connected Heisenberg Lie group N of dimension 2n+1, n . The main tools in our calculations are obtained by computing diagonal forms for certain incidence matrices that arise naturally in combinatorics.     

An O (n2) heuristic algorithm for the directed Steiner minimal tree problem

This paper describes the design of an O(N²) heuristic algorithm for the Directed Steiner Minimal Tree (DSMT) problem in the plane. The algorithm employs the Delaunay triangulation, a minimum spanning arborescence algorithm, and a triangulation of the arborescence to develop solutions to the DSMT problem. Example applications are also included.