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81.
An attempt has been made to apply Green’s function and partitioning technique to the case of XY2Z (ClO2F) pyramidal type molecule belonging toC, point group. The isotopic rules have been formulated. The force constants, rotation distortion constants and mean amplitude
of vibration have been computed and compared with other observed and calculated values whichever is available. 相似文献
82.
A new ion exchange membrane based on polyvinylidene fluoride (PVDF) and sulfonated poly(styrene-
divinylbenzene) was prepared by in-situ polymerization. The incorporation of sulfonic groups into the polyvinylidene fluoride composite membrane was confirmed by infrared spectroscopy (IR), ion exchange capacity (IEC) and energy dispersive X-ray analysis (EDAX). Area resistance, IEC and water uptake of the treated membrane were evaluated. When 20% of the crosslinked membrane was sulfonated at 80°C for 22 h, the PVDF ion exchange membrane can attain 0.8 Ω·cm2area resistance in NaCl aqueous solution at 25℃, IEC is as high as 2.43 millimoles per gram of the wet membrane. The
hydrophilicity of PVDF membrane is also significantly improved after treatment. When 60% of crosslinked membrane was sulfonated at 80 ℃ for 6 h, water uptake of the treated membrane can attain 64.7%. 相似文献
83.
A method is developed for determination of trace elements, including Ag, As, Cd, Co, Cr, Cu, Mn, Ni, Se, Tl and Zn, in fish otoliths by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS). Hydrofluoric acid was used to precipitate calcium resulting from acid dissolution of otolith calcium carbonate. Initial acidity of the sample solution influenced the precipitation efficiency of calcium fluoride. Up to 99.5% of Ca was precipitated in solutions that contained less than 2% (v/v) HNO3. Recoveries of the elements obtained from spiked artificial otolith solutions were between 90 and 103%. Stabilization of the elements within the ETV cell was achieved with 0.3 μg Pd/0.2 μg Rh chemical modifier that also afforded optimum sensitivity for multielement determination. The method was validated by the analysis of a fish otolith reference material (CRM) of emperor snapper, and then applied to the determination of the trace elements in otoliths of several fish species captured in Raritan Bay, New Jersey. Results indicated that fish physiology and biological processes could influence the levels of Cu, Mn, Se and Zn in the otoliths of fish inhabiting a similar aqueous environment. Otolith concentrations of Cr and Ni did not show any significant differences among different species. Concentrations for Ag, As, Cd, Co and Tl were also not significantly different, but were very low indicating low affinity of otolith calcium carbonate to these elements. 相似文献
84.
The mutual influence of the atoms on the composition of solid fluorine-containing antimony(iii) complexes formed in aqueous solutions in the (MF)
x
−(M′F)
n−x
−SbF3 (M, M′=Na, K, Rb, Cs, and NH4;n=1, 2;x=0 to 2), (KNO2)
n
−(KY)
n
−SbF3 (Y=F, Cl, SO4;n=0.5, 1), and K2SbF5−K2SbCl5 systems was investigated by elemental, X-ray, and thermogravimetric analyses and by IR and121,123Sb NQR spectroscopy. The isomorphism conditions for fluorine-containing antimony(iii) compounds resulting in the formation of complexes NaM′SbF5·1.5H2O (M′=K and Rb), K2SbF5·1.5H2O, NaCs3Sb4F16·H2O, KsbF3Cl, K2SbF2Cl3 with constant compositions, continuous M
x
M′2−x
SbF5 (0<x<2) and limited M
x
M′1−x
SbF4 (0.25<x<0.75; M, M′=K, Rb, Cs, and NH4) solid solutions or LiF+MSbF4 (M=Na, K, Rb, and Cs), M2SbF5+Cs2SbF5 (M=Na and K) and MSbF4+NaSbF4 (M=Rb and NH4) mechanical mixtures were determined.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 103–108, January, 1999. 相似文献
85.
Radio frequency plasma polymerization of vinylidene fluoride was used to modify the surface properties of nitrile rubber. The chemistry and frictional properties of the plasma films were characterized. FTIR transmission spectra and EDX analysis of plasma polymer films deposited on NaCl windows showed that the degree of fluorination of the plasma polymers increased as plasma power was increased from 25 to 50 W, and then decreased monotonically at higher powers. An estimation of the actual F/C ratio from EDX data indicated that the plasma polymer films contained approximately one fluorine atom for every 2–5 carbon atoms. Sliding friction tests on a Delrin countersurface showed that the coefficient of friction of the plasma treated rubbers was lower than untreated rubber, but slighly higher than rubber coated with silicone oil. Repetitive sliding friction testing showed that silicone oil treated samples had a longer lubricating lifetime than plasma treated samples. However, cyclic friction tests conducted with nitrile rubber o-rings yielded similar frictional behavior and lubricating lifetimes for silicone oil and plasma treatments. There was no correlation between chemical composition and the frictional and wear properties of the plasma films. Environmental scanning electron micrographs showed that the plasma films were brittle and tended to crack and flake off during wear testing. 相似文献
86.
Abraham F. Jalbout 《International journal of quantum chemistry》2007,107(6):1532-1539
This work presents the results of solvation of electrons on several hypothetical cyclooctane and cyclohexane molecular surfaces, using the hydrogen fluoride (HF) dimer. These complexes were constructed with extensive OH groups on one side of a hydrocarbon surface (i.e., cyclohexane sheets), which creates hydrogen‐bonded networks that can form, increasing the dipole moment of the system. Concurrently, the hydrogen atoms on the opposite side of the surface form a pocket of positive charge that can attract excess electrons. Two possible orientations for HF dimer solvation on eight molecular surfaces that have been demonstrated to be stable toward electron detachment are examined. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 相似文献
87.
Michael I. Bruce Michael Schulz Brian W. Skelton Allan H. White 《Journal of Cluster Science》2000,11(1):79-86
Addition of aqueous HCl to Ru5(
3-C=CH2)(-SMe)2(-PPh2)2(CO)10 afforded the structurally characterized carbyne complex Ru5(
3-SMe)(
3-CMe)(-Cl)(-SMe)(-PPh2)2(CO)9, formed by addition of H to the vinylidene ligand; a Cl atom bridges an Ru–Ru bond. 相似文献
88.
Deniz Sinirlioglu Ali Ekrem Muftuoglu Kurtulus Golcuk Ayhan Bozkurt 《Journal of polymer science. Part A, Polymer chemistry》2014,52(13):1885-1897
This work uses a simple “grafting through” approach in the preparation of anhydrous poly(vinylidene fluoride) (PVDF)‐g‐PVTri polymer electrolyte membranes (PEMs). Alkaline‐treated PVDF was used as a macromolecule in conjunction with vinyltriazole in the graft copolymerization. The obtained polymer was subsequently doped with triflic acid (TA) at different stoichiometric ratios with respect to triazole units and the anhydrous PEMs (PVDF‐g‐PVTri‐(TA)x) were prepared. All samples were characterized by FTIR and 1H NMR. The composition of PVDF‐g‐PVTri was determined by energy dispersive spectroscopy. Thermal properties of the membranes were examined by thermogravimetric analysis and differential scanning calorimetry. The surface roughness and morphology of the membranes were studied using atomic force microscopy, X‐ray diffraction, and scanning electron microscopy. PVDF‐g‐PVTri‐(TA)3 (C3‐TA3) with a degree of grafting of 47.22% showed a maximum proton conductivity of 0.09 S cm?1 at 150 °C and anhydrous conditions. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1885–1897 相似文献
89.
Ruthenium‐Catalyzed Cycloisomerization of 2,2′‐Diethynyl‐ biphenyls Involving Cleavage of a Carbon–Carbon Triple Bond 下载免费PDF全文
Prof. Dr. Takanori Matsuda Kotaro Kato Tsuyoshi Goya Shingo Shimada Prof. Dr. Masahiro Murakami 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(6):1941-1943
A ruthenium complex catalyzes a new cycloisomerization reaction of 2,2′‐diethynylbiphenyls to form 9‐ethynylphenanthrenes, thereby cleaving the carbon–carbon triple bond of the original ethynyl group. A metal–vinylidene complex is generated from one of the two ethynyl groups, and its carbon–carbon double bond undergoes a [2+2] cycloaddition with the other ethynyl group to form a cyclobutene. The phenanthrene skeleton is constructed by the subsequent electrocyclic ring opening of the cyclobutene moiety. 相似文献
90.
Bengi Yilmaz 《光谱学快报》2014,47(1):24-29
In this study, nano hydroxyapatite doped with yttrium (2.5, 5, and 7.5 mol%) and fluoride (2.5 mol%) ions were synthesized by precipitation method and sintered at 900°C, 1100°C, and 1300°C. Raman spectroscopy was applied to track the structural modifications in pure and doped hydroxyapatites. The results showed that the main characteristic band of pure hydroxyapatite at 963 cm?1 was not affected significantly by ion doping but exhibited higher intensity with increasing sintering temperature. Due to fluoride substitution, the 1048 and 1034 cm?1 bands of pure hydroxyapatites appeared with a wavenumber shift in the spectra of ion-doped hydroxyapatites. The 333 cm?1 band of pure hydroxyapatite disappeared and an additional calcium–fluor bond at 322 cm?1 was observable in ion-doped hydroxyapatites. Two fluorescence bands at 770 and 697 cm?1, which were also observed in the spectra of pure hydroxyapatites, shifted to higher wavenumbers in the spectra of ion-doped hydroxyapatites. This was considered to result from the perturbation in the hexagonal structure of hydroxyapatite due to yttrium and fluoride codoping. 相似文献