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1.
Hosseini M Ganjali MR Tavakoli M Norouzi P Faridbod F Goldooz H Badiei A 《Journal of fluorescence》2011,21(4):1509-1513
A novel and simple fluorescence enhancement method for selective pyrophosphate(PPi) sensing was proposed based on a 1:1 metal
complex formation between bis(8-hydroxy quinoline-5-solphonat) chloride aluminum(III) (Al(QS)2Cl), (L) and PPi in aqueous solution. The linear response range covers a concentration range of 1.6 × 10−7 to 1.0 × 10−5 mol/L of PPi and the detection limit of 2.3 × 10−8 mol/L. The association constant of L-PPi complex was calculated 2.6 × 105 L/mol. L was found to show selectively and sensitively fluorescence enhancement toward PPi over than I3-, NO3-, CN−, CO32−, Br−, Cl−, F−, H2PO4− and SO42−, which was attributed to higher stability of inorganic complex between pyrophosphate and L. 相似文献
2.
Different amounts of Li3PO4 were mixed to a fixed ratio of LiI:Li2WO4, ground and pelletised before subjected to sintering at 70°C for 7 days. XRD shows that the product formed after sintering
process is most likely Li6P4W8O32 due to peaks present at 10.6°, 22.4°, 24.0°, 24.4, 26.2°, 32.4° and 34.0°. Conductivity studies show that the sample with
25 wt.% Li3PO4 exhibits the highest room temperature conductivity of 3.42×10−3 Scm−1. Conductivity is expected to occur through channel-like structures which could have formed due to corner or edge sharing
of polyhedra. FTIR studies have shown the existence of WO4 tetrahedra and WO6 octahedral at 850 cm−1 and 952 cm−1, and phosphate tetrahedral at 564 cm−1, 700 cm−1, 890 cm−1 and 1030 cm−1. 相似文献
3.
Yaping Li Jie Shao Xudong Yu Xiufang Xu Hai Lin Zunsheng Cai Huakuan Lin 《Journal of fluorescence》2010,20(1):3-8
Two simple fluorescent anion receptors based on 1-phenyl-3-methylpyrozole-5-one-4-one phenylhydrazone (L1) and 1-phenyl-3-methylpyrozole-5-one-4-one
p-nitrophenylhydrazone (L2) were designed, synthesized and characterized with 1H NMR, COSY spectrum, 13C NMR, ESI-mass and elemental analyse. Interestingly, two receptors with similar configuration exhibited different anion binding
behaviors in DMSO solution. The results of Job plots and ESI-mass spectrum indicate that L1 bind anions such as F−, AcO−, H2PO4− to form 2:1 host-guest complexation, while L2 bind anions to form 1:1 host-guest complexation in the solution. 相似文献
4.
Mixtures of LiI–Li3PO4 were sintered at low temperature. It was observed that the conductivity improved up to 10−3 S cm−1 with the addition of LiI. Infrared technique (Fourier transform infrared spectroscopy [FTIR]) was employed to detect the
presence of polyhedral structures. From the FTIR spectra of the binary samples with various weight percents of LiI, the PO4
3− bands and the PO bending experienced small shifting which indicates that interaction has occurred. Alternating current conductivity
versus frequency shows a linear variation suggesting that the behavior follows Jonsher power law. The conduction mechanism
of LiI–Li3PO4 solid electrolyte follows the quantum mechanical tunneling model. 相似文献
5.
Xipu He Junli Huang Liya Zhou Qi Pang Fuzhong Gong 《Central European Journal of Physics》2012,10(2):514-518
A series of new red phosphors, MZr2(PO4)3:Eu3+; Bi3+ (M=Na; K), were synthesized using the solidstate reaction method, and their photoluminescence spectra were measured. The
MZr2(PO4)3:Eu3+; Bi3+ (M=Na; K) phosphors were efficiently excited by an ultraviolet (UV; 395 nm) source, and showed intense orange-red emission
at 595 nm. Further investigation of the concentration-dependent emission spectra indicated that the MZr2(PO4)3:Eu3+; Bi3+ (M=Na; K) phosphors exhibit the strongest luminescence intensity when y = 0.01 in NaZr2(0:95−y)(PO4)3:Eu0.103+, Bi2y
3+ and y = 0.09 in NaZr2(0.95−y)(PO4)3:Eu0.103+, Bi2y
3+, whereas the relative PL intensity decreases with increasing Bi3+ concentration due to concentration quenching. The addition of Bi3+ widens the excitation band of NaZr2(0.95−y)(PO4)3:Eu0.103+, Bi2y
3+ around 320 nm, which provides the useful idea of broadening the excitation band around 300–350 nm to fit the ultraviolet
chip. 相似文献
6.
A novel ultrasonic-assisted sol–gel method is proposed to prepare Li3V2(PO4)3/C cathode material. X-ray diffraction analyses show that both Li3V2(PO4)3/C(A) synthesized by the ultrasonic-assisted sol–gel method and Li3V2(PO4)3/C(B) synthesized by a traditional sol–gel method have monoclinic structure. Scanning electron microscopy images indicate
that the Li3V2(PO4)3/C(A) composite has a more uniform morphology than that of the Li3V2(PO4)3/C(B) composite. In the voltage range of 3.0–4.3 V (vs. Li/Li+), the initial specific discharge capacities of the Li3V2(PO4)3/C(A) and Li3V2(PO4)3/C(B) samples are 129.8 and 125.9 mAh g−1 at 1C rate (1C = 133 mA g−1), respectively. Furthermore, at 2-C charge/10-C discharge rate, the specific discharge capacity of the Li3V2(PO4)3/C(A) composite retains 113.2 mAh g−1 after 50 cycles, but the Li3V2(PO4)3/C(B) composite only presents a capacity of 94.8 mAh g−1. 相似文献
7.
A. S. Zubkov V. I. Artyukhov L. A. Chernozatonskii O. S. Nedelina 《Russian Journal of Physical Chemistry B, Focus on Physics》2011,5(5):748-764
Electron transfer is an elementary chemical event involved in many biochemical reactions. Experiments have shown that some
oxyacids participating in electron transport are capable of dissociative capture of low-energy electrons, a process indicative
of the formation of a metastable anion. The present work reports the results of quantum-chemical simulations of the dissociative
electron attachment to a number of oxyacids (H3PO4, H2SO4−, HPO42−, H2SO4, HSO4−, B(OH)4−, HCOOH) with formation of a hydrogen atom in vacuum and in the aqueous medium. Phosphate is one of the most important building
units of biological molecules, whereas formic acid can serve as a model of the −COOH group in amino acids, carboxylic acids,
functional sites of enzymes, etc. The electron affinity of these oxyacids in the aquatic environment is positive and exceeds
the energy of hydrogen atom abstraction. The proton of the OH group captures the electron, while the aquatic environment stabilizes
it in the trapped state due to its polarizability. The data obtained provide a fresh look at the phenomenon of proton-assisted
electron transfer and at the use of oxyacid buffers. 相似文献
8.
LiFePO4-C was prepared by the solid-state reaction using LiH2PO4, Fe2O3, and glucose as raw materials, which is a green and low-cost method. Thermogravimetry, differential scanning calorimetry,
X-ray diffraction, and element analyzer were used to study the phase and carbon content of the synthesized samples. The optimum
conditions for synthesizing LiFePO4 are identified. The discharge capacity of 120 mAh g−1 was achieved at a current density of 100 mA g−1 between 2.5 and 4.2 V during the first 50 cycles. 相似文献
9.
Water-soluble Mn2+-doped ZnS quantum dots (QDs) were prepared using mercaptoacetic acid as the stabilizer. The optical properties and structure
features were characterized by X-Ray, absorption spectrum, IR spectrum and fluorescence spectrum. In pH 7.8 Tris-HCl buffer,
the QDs emitted strong fluorescence peaked at 590 nm with excitation wavelength at 300 nm. The presence of sulfide anion resulted
in the quenching of fluorescence and the intensity decrease was proportional to the S2− concentration. The linear range was from 2.5 × 10−6 to 3.8 × 10−5 mol L−1 with detection limit as 1.5 × 10−7 mol L−1. Most anions such as F−, Cl−, Br−, I−, CH3CO2
−, ClO4
−, CO3
2−, NO2
−, NO3
−, S2O3
2−, SO3
2− and SO4
2− did not interfere with the determination. Thus a highly selective assay was proposed and applied to the determination of
S2− in discharged water with the recovery of ca. 103%. 相似文献
10.
Polyvinyl alcohol (PVA)-based proton conducting polymer electrolytes have been prepared by the solution cast technique. The
conductivity is observed to increase from 10−9 to 10−4 S cm−1 as a result of orthophosphoric acid (H3PO4) addition. The plot of conductivity vs temperature shows that a phase transition occurred at 343 K in the sample PVA-33 wt%
H3PO4. The β-relaxation peak is observed at 313 K. The glass transition temperature of PVA-33 wt% H3PO4 is 343 K. Orthophosphoric acid seems to play a dual role, i.e., as a proton source and as a plasticizer. The ac conductivity
σ
ac = Aω
s was also calculated in the temperature range from 303 to 353 K. The conduction mechanism was inferred by plotting the graph
of s vs T from which the conduction mechanism for sample PVA-17 wt% H3PO4 was inferred to occur by way of the overlapping large polaron tunneling (OLPT) model and the conduction mechanism for the
sample PVA-33 wt% H3PO4 by way of the correlated barrier height (CBH) model. 相似文献
11.
LiCo1−x
Mn
x
PO4/C cathode materials are selectively synthesized by a solvothermal method in ethylene glycol solvent using glucose, LiCl,
H3PO4, MnCl2·4H2O, and Co(NO3)2·6H2O as precursors. The obtained samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and
transmission electron microscopy (TEM) and the electrochemical performances are also evaluated using a LAND CT2001A battery
test system at room temperature. XRD result demonstrates the formation of LiCo1−x
Mn
x
PO4 solid solution and the enlarged channels are benefit for Li+ migration. SEM graph indicates that the particle size of LiCo0.5Mn0.5PO4/C is about several hundred nanometers and aggregates to large particles located in the range of 2–3 μm. TEM image illustrates
that the core/shell-structured LiCo0.5Mn0.5PO4/C solid solution is indeed obtained by this method. The high specific surface area (35 m2/g) of LiCo0.5Mn0.5PO4/C could make this solid solution contact with the electrolyte more sufficiently and benefit for Li+ transportation. The capacity, flat voltage, and cyclical stability of LiCo1−x
Mn
x
PO4/C are improved compared to LiMnPO4 and LiCoPO4 due to the improved electronic conductivity and lithium-ion conductivity which resulted from carbon coating and foreign element
incorporation. 相似文献
12.
Among the trivalent ion conductors reported, the highest ion conductivity was realized with the trivalent Al3+ ion conducting (AlxZr1−x)4/(4−x)Nb(PO4)3 solid electrolyte and the value enters into the region between yttria stabilized zirconia (YSZ) and calcia stabilized zirconia
(CSZ) that are well known to be high oxide anion conductors commercialized. The improvement of the ion conductivity and the
mechanical strength was simultaneously achieved by adding B2O3 during the sintering procedure. The Al3+ ion conducting (AlxZr1−x)4/(4−x)Nb(PO4)3 solid electrolyte with B2O3 treatment was combined with YSZ, and the 0.7La2O2SO4-0.3Li2SO4 solid was attached on the (AlxZr1−x)4/(4−x)Nb(PO4)3 solid surface as the auxiliary electrode for sulfur dioxide (SO2) gas sensing. The sensor response was rapid, reproducible and continuous with obeying the Nernst theoretical relationship.
Paper presented at the Patras Conference on Solid State Ionics — Transport Properties, Patras, Greece, Sept. 14 – 18, 2004. 相似文献
13.
Thin sodium superionic conductor (Nasicon) coatings are deposited on rotating substrates by co-sputtering in the reactive
mode of a Zr-Si and a Na3PO4 target. The influence of the discharge current and of the target-to-substrate distance is investigated owing to the targeted
Na3Zr2Si2PO12 stoichiometry. A thermo-structural analysis shows that the amorphous as-deposited coating of convenient composition crystallises
around 700 °C in the monoclinic structure. Electrical measurements performed at room temperature after various annealing treatments
indicate a ionic conductivity of about 2·10−3 S·cm−1, consistent with that of bulk Nasicon.
Paper presented at the Patras Conference on Solid State Ionics — Transport Properties, Patras, Greece, Sept. 14 – 18, 2004. 相似文献
14.
We studied the spectral-luminescent characteristics of the luminescence of mixed-ligand polypyridine-phosphine complexes of
ruthenium(II) cis-[Ru(bpy)2(PPh3)X](BF4)
n
with ligands 2,2′-bipyridyl (bpy) and triphenylphosphine (PPh3) and X = Cl−, Br−, CN−, NO2−, NH3, MeCN, pyridine (py), 4-aminopyridine (pyNH2), and 4,4′-bipyridyl (4,4′-bpy) in a 4: 1 EtOH-MeOH alcoholic mixture at 77 K. The radiative and nonradiative deactivation
rate constants of the lowest electronically excited state of the complexes are determined. We find that triphenylphosphine
has a greater effect on the photophysical characteristics of ruthenium(II) complexes compared to π-acceptor strong-field ligands,
such as MeCN, CN−, and NO2−. At the same time, the characteristics of complexes cis-[Ru(bpy)2(PPh3)X]
n+ considerably depend on the nature of the second monodentate ligand X, which is coordinated to ruthenium(II), and correlate
with its position in the spectrochemical series of ligands. 相似文献
15.
The optimisation of the morphology of WO3 thin films allowed a more efficient electrochromic colouring using Na+ ions than H+ ones. Therefore, sodium superionic conductor (Na3Zr2Si2PO12, NASICON) films may be used as electrolyte in inorganic electrochromic devices. In this paper, the structure, chemical composition,
morphology and electrochromic properties of WO3, ZnO:Al and Na3Zr2Si2PO12 thin films were studied to develop a novel type of electrochromic device. WO3, ZnO:Al and Na3Zr2Si2PO12 thin films were deposited using reactive magnetron sputtering of tungsten, zinc and aluminium and Zr–Si and Na3PO4 targets, respectively. For transparent conductive oxide coatings, a correlation was established between the deposition parametres
and the film’s structure, transmittance and electrical resistivity. Classical sputtering methods were not suitable for the
deposition of NASICON films on large surface with homogenous composition. On the other hand, the use of high-frequency pulsed
direct current generators allowed the deposition of amorphous films that crystallised after thermal annealing upon 700 °C
in the Na3Zr2Si2PO12 structure. Amorphous films exhibited ionic conductivity close to 2 × 10−3 S cm−1. Finally, preliminary results related to the electrochromic performance of NASICON, WO3 and indium tin oxide devices were given.
Paper presented at the 11th EuroConference on the Science and Technology of Ionics, Batz-sur-Mer, France, Sept. 9–15, 2007. 相似文献
16.
Apatite is a mineral with general formula M10(XO4)6Z2, where M are metallic elements such as Li+, Na+, K+, Ca2+, Sr2+, Ba2+, Ln3+ etc.; X=P, V, S, Si, Ge, Re, Cr etc; Z=F−, Cl−, I−, OH−, O2−, S2− etc. Some materials with apatite structure (S.G. P63/m) exhibit quite high cationic (Li+, H+ etc.) and/or anionic (F−, Cl− etc.) conduction. Recently, it was reported that some rare earth silicates, e.g., La10(SiO4)6O3, exhibit quite high oxide-ion conductivity. In this paper, we discuss chemical composition, structure, synthetic procedure
and ionic conduction of apatite-type materials. Recent improvements are briefly reviewed. High ionic conductivity has been
observed for both cation deficient, oxygen stoichiometric La9.33(SiO4)6O2 and cation stoichiometric, oxygen excess La10(SiO4)6O3 compositions. Grain boundary conductivity is usually low, which tends to dominate the impedance response. The resistance,
particularly the grain boundary resistance is also found to depend on pO2.
Paper presented at the 7th Euroconference on Ionics, Calcatoggio, Corsica, France, Oct. 1–7, 2000. 相似文献
17.
N. Imanaka 《Ionics》2003,9(1-2):36-40
New types of multivalent ion conducting solid electrolytes have been extensively developed and their applications for chemical
sensors were investigated. Among the trivalent ion conductors, the highest ion conductivity was realized with the (AlxZr1−x)4/(4−x)Nb(PO4)3 solid electrolyte and the value reaches the region between yttria stabilized zirconia (YSZ) and calcia stabilized zirconia
(CSZ) of the representative oxide anion conductors. The above described Al3+ ion conducting (AlxZr1−x)4/(4−x)Nb(PO4)3 solid electrolyte was combined with YSZ, with accompanying the Y2O3-KNO2 solid solution as an auxiliary electrode for nitrogen monoxide (NO) gas sensing. The sensor response was rapid and a reproducible
output was continuously observed obeying the Nernst theoretical relationship in a typical NO gas content region in exhaust
gases.
Paper presented at the 9th EuroConference on Ionics, Ixia, Rhodes, Greece, Sept. 15 – 21, 2002. 相似文献
18.
N. Nishida S. Okuma H. Miyatake S. Shiratake Y. Hidaka T. Murakami Y. Ueda K. Kosuge S. Kambe H. Yasuoka H. Takagi S. Uchida K. Nishiyama K. Nagamine Y. Kuno T. Yamazaki 《Hyperfine Interactions》1991,65(1-4):1027-1034
The negative muon spin rotation method (μ− SR) has been applied to studies of electronic states at oxygen sites of oxide superconductors YBa2Cu3O7, Nd2−x
Ce
x
CuO4−δ (x=0.15, oxygen reduced), LiTi2O4 and related oxide-insulators La2CuO4−δ, CuO, Cu2O. The paramagnetic shifts of μ− trapped at oxygen nuclei in these polycrystalline powder samples have been measured at 300 K. All the measured shifts are
positive. In copper-oxides the paramagnetic shifts are of the order 10−3, while in LiTi2O4 is very small (8.4±3.34×10−5). In YBa2Cu3O7, a fast μ− spin relaxation timeT
2
* (∼ 200 ns) has been observed; the reason for this is unknown and further studies are now in progress. 相似文献
19.
We investigate the vibrational spectra of crystals of ternary orthophosphates Me7Eu2UO2·(PO4)5 (Me–Na, Rb, Cs) obtained by solid-phase synthesis. We show that in these materials the effect of coordination distorts the
geometry of the PO
4
3−
tetrahedron and decreases its symmetry. We conclude that the PO
4
3−
tetrahedrons in Me7Eu2UO2(PO4)5 occupy two nonequivalent positions in the lattice. The character of manifestation and the number of oscillation frequencies
observed allow the assumption that they have the C3v- and C2-symmetry. This symmetry of two crystallographically nonequivalent groups of PO
4
3−
ensures a complete set of bands in the IR absorption spectra of the crystals investigated. We show that these crystals exhibit
chain structural motifs.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol, 64, No. 4, pp. 467–470, July–August, 1997. 相似文献
20.
In this communication the ion transport properties of polyvinyl alcohol complexed with orthophosphoric acid (H3PO4) have been investigated. The proton conduction is confirmed by hydrogen gas evolved at the cathode of the coulometer and
the transference number of H+ ion has been determined. The transient ionic current (TIC) technique has been used to detect the mobile ionic species and
their mobilities are evaluated. The ionic mobility was found to be of the order of 10−4 cm2.V−1.s−1 for H+ ions. It is observed that the bulk electrical conductivity increases with the temperature following the Arrhenius type behaviour.
Variation of charge carrier concentration with the molar ratio of H3PO4 in the sample reveals that the carrier concentration is largely affected by the amount of dopant in the complexes. 相似文献