Organometallic Chemistry of Diphosphazanes. 11. Reactions of fac-[Mo(CO)3(MeCN){.eta.2-Ph2PN(Pri)PPh(DMP)}] (DMP = 3,5-Dimethyl-1-Pyrazolyl) with Diphosphazanes and Diphosphinoalkanes and Oxidative Addition with Iodine

The use of fac-[Mo(CO)(3)(MeCN)(eta(2)-L(1))] (1a) {L(1) = Ph(2)PN(Pr-i)PPh(DMP)}(2) as a precursor to metalloligands and bimetallic, heterotrimetallic, and heptacoordinated complexes is reported. The reaction of 1a with diphosphazane, dppa, or a diphosphinoalkane such as dppm or dppe yields the fac-eta(1)-diphosphine substituted metalloligands, fac-[Mo(CO)(3)(eta(2)-L(1))(eta(1)-PXP)] {PXP = dppa (2), dppm (3), and dppe (4)}. These undergo isomerization to yield the corresponding mer-diphosphine complexes (5-7). Oxidation of the uncoordinated phosphorus atom of the mer-eta(1)-dppm-substituted complex eventually provides mer-[Mo(CO)(3)-(eta(2)-L(1)){eta(1)-Ph(2)PCH(2)P(O)Ph(2)}](8). The structure of the latter complex has been confirmed by single crystal X-ray diffraction {triclinic system, P ($) over bar 1; a = 11.994(3), b = 14.807(2), c = 15.855(3) Angstrom; alpha = 114.24(1), beta = 91.35(2), and gamma = 98.95(1)degrees; Z = 2, 4014 data (F-0 > 5 sigma(F-0)), R = 0.066, R(W) = 0.069}. Treatment of the dppe metalloligand 7 with [PtCl2(COD)] yields the heterotrimetallic complex cis-[PtCl2{mer-[Mo(CO)(3)(eta(2)-L(1))(eta(1)-dppe]}(2)] (9). Attempts to prepare a related trimetallic complex with the dppm-containing metalloligand were unsuccessful; only the tetracarbonyl complex cis-[Mo(CO)(4)(eta(2)-L(1))] (1b) and cis-[PtCl2(eta(2)-dppm)] were obtained. Reaction of la with dppe in the ratio 2:1 yields the mer-mer dinuclear complex [{mer-[Mo(CO)(3)(eta(2)-L(1))]}(2)(mu-dppe)] (10) bridged by dppe. Oxidation of 1a with iodine yields the Mo(II) heptacoordinated complex [MoI2(CO)(2)(eta(3)-L(1))] (11) with tridentate PPN coordination. The same Mo(II) complex 11 is also obtained by the direct oxidation of the tetracarbonyl complex cis-[Mo(CO)(4)(eta(2)-L(1))] (1b) with iodine. The structure of 11 has been confirmed by X-ray diffraction studies {monoclinic system, Cc; a = 10.471(2), b = 19.305(3), c = 17.325(3) Angstrom; beta = 95.47(2)degrees; Z = 4, 3153 data (F-0 > 5 sigma(F-0)), R = 0.049, R(W) = 0.051}. This complex exhibits an unusual capped-trigonal prismatic geometry around the metal. A similar heptacoordinated complex 12 with a chiral diphosphazane ligand {L(3) = (S,R)-P(h)2PN-(*CHMePh)*PPh(DMP)} has also been synthesized.

Proceedings of the 1998 Science Board Symposium on The Impacts of the 1997/98 El Niño Event on the North Pacific Ocean and Its Marginal Seas

Preface [pdf, 0.01 Mb] James J. O'Brien The big picture - The ENSO of 1997-98 [pdf, 0.01 Mb] James E. Overland, Nicholas A. Bond & Jennifer Miletta Adams Atmospheric anomalies in 1997: Links to ENSO? [pdf, 0.54 Mb] Vladimir I. Ponomarev, Olga Trusenkova, Serge Trousenkov, Dmitry Kaplunenko, Elena Ustinova & Antonina Polyakova The ENSO signal in the northwest Pacific [pdf, 0.47 Mb] Robert L. Smith, A. Huyer, P.M. Kosro & J.A. Barth Observations of El Niño off Oregon: July 1997 to present (October 1998) [pdf, 1.31 Mb] Patrica A. Wheeler & Jon Hill Biological effects of the 1997-1998 El Niño event off Oregon: Nutrient and chlorophyll distributions [pdf, 1.13 Mb] William T. Peterson Hydrography and zooplankton off the central Oregon coast during the 1997-1998 El Niño event [pdf, 0.26 Mb] William Crawford, Josef Cherniawsky, Michael Foreman & Peter Chandler El Niño sea level signal along the west coast of Canada [pdf, 1.25 Mb] Howard J. Freeland & Rick Thomson The El Niño signal along the west coast of Canada - temperature, salinity and velocity [pdf, 0.49 Mb] Frank A. Whitney, David L. Mackas, David W. Welch & Marie Robert Impact of the 1990s El Niños on nutrient supply and productivity of Gulf of Alaska waters [pdf, 0.06 Mb] Craig McNeil, David Farmer & Mark Trevorrow Dissolved gas measurements at Stn. P4 during the 97-98 El Niño [pdf, 0.13 Mb] Kristen L.D. Milligan, Colin D. Levings & Robert E. DeWreede Data compilation and preliminary time series analysis of abundance of a dominant intertidal kelp species in relation to the 1997/1998 El Niño event [pdf, 0.05 Mb] S.M. McKinnell, C.C. Wood, M. Lapointe, J.C. Woodey, K.E. Kostow, J. Nelson & K.D. Hyatt Reviewing the evidence that adult sockeye salmon strayed from the Fraser River and spawned in other rivers in 1997 [pdf,0.03 Mb] G.A. McFarlane & R.J. Beamish Sardines return to British Columbia waters [pdf, 0.34 Mb] Ken H. Morgan Impact of the 1997/98 El Niño on seabirds of the northeast Pacific [pdf, 0.06 Mb] Thomas C. Royer & Thomas Weingartner Coastal hydrographic responses in the northern Gulf of Alaska to the 1997-98 ENSO event [pdf, 0.76 Mb] John F. Piatt, Gary Drew, Thomas Van Pelt, Alisa Abookire, April Nielsen, Mike Shultz & Alexander Kitaysky Biological effects of the 1997/98 ENSO in Cook Inlet, Alaska [pdf, 0.22 Mb] H.J. Niebauer The 1997-98 El Niño in the Bering Sea as compared with previous ENSO events and the "regime shift" of the late 1970s [pdf, 0.10 Mb] A.S. Krovnin, G.P. Nanyushin, M.Yu. Kruzhalov, G.V. Khen, M.A. Bogdanov, E.I. Ustinova, V.V. Maslennikov, A.M. Orlov, B.N. Kotenev, V.V. Bulanov & G.P. Muriy The state of the Far East seas during the 1997/98 El Niño event [pdf, 0.15 Mb] Stacy Smith & Susan Henrichs Phytoplankton collected by a time-series sediment trap deployed in the southeast Bering Sea during 1997 [pdf, 0.21 Mb] Cynthia T. Tynan Redistributions of cetaceans in the southeast Bering Sea relative to anomalous oceanographic conditions during the 1997 El Niño [pdf, 0.02 Mb] Akihiko Yatsu, Junta Mori, Hiroyuki Tanaka, Tomowo Watanabe, Kazuya Nagasawa, Yikimasa Ishida, Toshimi Meguro, Yoshihiko Kamei & Yasunori Sakurai Stock abundance and size compositions of the neon flying squid in the central North Pacific Ocean during 1979-1998 [pdf, 0.11 Mb] O.B. Feschenko A new point of view concerning the El Niño mechanism [pdf, 0.01 Mb] Nathan Mantua 97/98 Ocean climate variability in the northeast Pacific: How much blame does El Niño deserve? [pdf, 0.01 Mb] Vadim P. Pavlychev Sharp changes of hydrometeorological conditions in the northwestern Pacific during the 1997/1998 El Niño event [pdf, 0.01 Mb] Jingyi Wang Predictability and forecast verification of El Niño events [pdf, 0.01 Mb] (Document contains 110 pages)

Some observations on the behaviour of plankton in waters discharged by the lakes [Translation from: Ost.bot.Zeit 103(1), 98-109, 1955]

This information is based on the limnological observations of the very interesting and remarkable discharge of the Lunzer Obersee, (1117m). On journeying towards the Mittersee, the Lunzer Obersee discharge takes on all the characteristics of spring-water; it was found to be of interest to take note of the change of the composition of the water on those stretches of the course where it flows shows the ground. For this purpose it was necessary to take temperature-recordings, chemical examination of the water and a quantitative determination of the plankton. Samples were taken in 1954 of zooplankton at different times of the year at the discharge of the lake and analysed. The significant loss of organisms in the way of discharge is discussed.

静压下ZnS（0.02）Te（0.98）混晶的共振喇螺散射研究

于2010-11-23批量导入

Multi-electron processes in C-13(6+) ions with neon collisions in energy region 4.15-11.08 keV/u

The cross-section ratios of double-, triple-, quadruple-, and the total multi-electron processes to the single electron capture process sigma(DE)/sigma(SC), sigma(TE)/sigma(SC), sigma(QE)/sigma(SC) and sigma(ME)/sigma(SC)) as well as the relative ratios among reaction channels in double-electron active, triple-electron active and quadruple- electron active are measured in C-13(6+) -Ne collision in the energy region of 4.15-11.08 keV/u by employing position-sensitive and time-of-flight coincident techniques. It is determined that the cross-section ratios sigma(DE)/sigma(SC), sigma(TE)/sigma(SC), sigma(QE)/sigma(SC) and sigma(ME)/sigma(SC) are approximately the constants of 0.20 +/- 0.03, 0.16 +/- 0.04, 0.06 +/- 0.02 and 0.42 +/- 0.05. These values are obviously smaller than the predictions of the molecular Coulomb over-the-barrier model (MCBM) [J. Phys. B 23 (1990) 4293], the extended classical over-the-barrier model (ECBM) [J. Phys. B 19 (1986) 2925] and the semiempirical scaling laws (SL) [Phys. Rev. A 54 (1996) 4127]. However, the relative ratios among partial processes of DE, TE and QE are found to depend on collision energy, which suggests that the collision dynamics depends on the collision velocity. The limitation of velocity-independent character of ECBM, MCBM and SL is undoubtedly shown.

Thermal-shock resistance of LnMgAl(11)O(19) (Ln = La, Nd, Sm, Gd) with magnetoplumbite structure

Lanthanide hexaaluminates including LaMgAl11O19, NdMgAl11O19, SmMgAl11O19 and GdMgAl11O19 were synthesized via Sol-Gel method. Due to the anisotropic crystal growth, these oxides crystallize in the form of platelets and the platelet thickness increases with the decrease of rare-earth ionic radius. It was observed that the thermal-shock resistances of LaMgAl11O19, NdMgAl11O19 and SmMgAl11O19 oxides were superior to 8YSZ as proved by water quenching tests. In addition, the thinner the platelet. the more interstices are retained in the sintered specimen, and the better thermal-shock resistance the oxide has. Based on SEM images, it can be seen that the SmMgAl11O19 sample exhibits a mixture of the intergranular and transgranular fracture after thermal cycling failure.

Electrochemistry of Microperoxidase-11 (MP-11) on Glassy Carbon Electrode Modified with Chitosan

In this paper, microperoxidase-11 (MP-11) was immobilized on glassy carbon electrode surface modified with chitosan by physical adsorption. The direct electrochemistry and the electrocatalytic behaviours to O-2 and the H2O2 of MP-11 on glassy carbon electrode modified with chitosan were characterized by cyclic voltammetry. The results indicate that MP-11 on modified electrode displays a quasi-reversible electrochemical process coupled with proton transfer in the phosphate buffer solutions(pH = 7.12). Direct electrochemical reaction of MP-11 on modified electrode has been realized. MP-11 on modified electrode can catalyze reduction for O-2 and H2O2. Both of the catalytic reductions are surface-controlled electrochemical process.

Resonance Raman and surface-enhanced Raman spectroscopic study of microperoxidase-11

The electron transfer and structure of microperoxidase-11(MP-11) in solution and at electrode/solution interface were studied by electrochemical, resonance Raman and surface-enhanced Raman spectroscopic techniques. Results show that the central iron in heme group was six-coordinated in solution, whereas it was converted to five-coordinated state as MP-11 was adsorbed on the surface of a roughened silver electrode, due to the reorientation of MP-11 molecules. The electrochemical properties of MP-11 were directly affected by the coordination state of heme iron.

Influence of annealing on structure of Nylon 11

Differential scanning calorimeter (DSC), wide-angle X-ray diffraction (WAXD), small-angle X-ray scattering (SAXS), and density techniques have been used to investigate the structural parameters of the solid state of Nylon 11 annealed at different temperatures. The equilibrium heat of fusion Delta H-m(0) and equilibrium melting temperature T-m(0) were estimated to be 189.05 J g(-1) and 202.85 degrees C respectively by using the Hoffman-Weeks approach. The degree of crystallinity (W-c,W-x) ranged approximately 24-42% was calculated by WAXD and compared with those by calorimetry (W-c,W-h) and density (W-c,W-d) measurements. The radius of gyration R-g, crystalline thickness L-c, noncrystalline thickness L-a, long period L, semiaxes of the particles (a, b), electron-density difference between the crystalline and noncrystalline regions eta(c) - eta(a), and the invariant Q increased with increasing annealing temperature. The analysis of the SAXS data was based upon the particle characteristic function and the one-dimensional electron-density correlation function. An interphase region existed between the crystalline and noncrystalline region with a clear dimension of about 2 nm for semicrystalline Nylon 11. Instead of the traditional two-phase model, a three-phase model has been proposed to explain these results by means of SAXS.

Electrocatalytic reduction of O-2 and H2O2 at the glass carbon electrode modified with microperoxidase-11

Electrocatalytic reduction of O-2 and H2O2 at the glass carbon electrode modified with microperoxidase-11 immobilized with Nafion film has been studied by means of cyclic voltammetry and rotating disk electrode techniques. The modified electrode shows high catalytic activity toward the reduction of both O-2 and H2O2. The rate constants of Oz and H2O2 reduction at the modified electrode have been measured and compared. It is found that O-2 undergoes a four-electron reduction at the modified electrode and the catalytic activity for the reduction of O-2 is dependent on the pH of the solutions.

Crystal transformation of Nylon 11 using in situ WAXD

alpha Form Nylon 11 films were found to exist a non-linear transformation at 70 degrees C during the heating process using in situ WAXD. The alpha Form disappeared but delta Form appeared when the temperature was higher 70 degrees C.

Electrochemistry and spectroscopy study on the interaction of microperoxidase-11 with lipid membrane

The interaction of microperoxidase-11 (MP11) with cationic lipid vesicles of didodecyldimethylammonium bromide (DDAB) induces an alpha -helical conformation from random coil conformations in solution and this change then makes heme macrocycle more distorted. DDAB-induced MP11 conformations were investigated by cyclic votammetry (CV), circular dichroism (CD) and UV-vis spectrometry. All results indicate that the binding of MP11 in solution to DDAB vesicles and the ordered structure formation are driven by mostly electrostatic interaction between negatively charged residues in the undecapeptide and positively charged lipid headgroups on the membrane surface. Upon binding to DDAB, its half-peak potential was also changed. The mechanism of the interaction between MP11 and DDAB was also discussed. (C) 2001 Elsevier Science B.V. All rights reserved.

Morphology of conductive blend fibers of polyaniline and polyamide-11

Polyaniline (PANI), a member of the intrinsically conducting polymer (ICPs) family, was blended with polyamide-11 (polyco-aminoundecanoyle) in concentrated sulfuric acid. The above solution was used to spin conductive PANI/polyamide-11 fibers by wet-spinning technology. Scanning electron microscope (SEM) and transmission electron microscope (TEM) were employed to study the two-phase morphology of the conductive PANI/polyamide-11 fibers. The micrographs of the cross-section, the axial section and the surface of the monofilament demonstrated that the two blend components were incompatible. The morphology of PANI in the fibers was of fibrillar form, which was valuable for producing conducting channels. The electrical conductivity of the fibers was from 10(-6) to 10(-1) S/cm with the different PANI fraction and the percolation threshold was about 5 wt.%. By comparing the two blend systems of PANI/Polyamide-11 fibers and carbon black filled poly(ethylene terephthalate) (PET) fibers, it was shown that the morphology of the conductive component had an influence on electrical conductivity, The former had higher conductivity and lower percolation threshold than the latter. (C) 2001 Elsevier Science B.V. All rights reserved.

Crystal transitions of Nylon 11 under drawing and annealing

The crystal transitions of Nylon 11 annealed and drawn at different temperatures (T-d) with different drawing ratios (n) were investigated by wide-angle X-ray diffraction (WAXD). The alpha -form of Nylon Il could be transformed from the delta'-form by annealing at high temperature, The results showed that the crystal transitions of Nylon 11 strongly depended on the thermal history and the conditions of drawing. The delta'-form Nylon Il could he gradually transformed into the alpha -form when it was drawn at high temperature and the alpha -form was only partly transformed into the delta'-form when it was drawn at low temperature. This should be due to the effect of the competition between thermal inducement and drawing inducement. The thermal inducement was favorable to producing the alpha -form, while the drawing inducement was favorable to producing the delta'-form. (C) 2001 Elsevier Science Ltd. All rights reserved.