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1.
The reactions of K3[Cu(CN)4], R3SnCl (R = Me or ph) and 2,3-dimethyl quinoxaline (dmqox) in H2O/acetonitrile media at room temperature afford the 3D-supramolecular coordination polymers (SCP) 3 [ \textCu 2 ( \textCN ) 2 \textdmqox ] ^{ 3}_{\infty } \left[ {{\text{Cu}}_{ 2} \left( {\text{CN}} \right)_{ 2} {\text{dmqox}}} \right] , 1 and 3 [ \textCu 2 ( \textCN ) 4 ·( \textPh 3 \textSn ) 2 ·\textdmqox ] ^{ 3}_{\infty } \left[ {{\text{Cu}}_{ 2} \left( {\text{CN}} \right)_{ 4} \cdot \left( {{\text{Ph}}_{ 3} {\text{Sn}}} \right)_{ 2} \cdot {\text{dmqox}}} \right] , 2. The structure of the tin free 1 consists of parallel zigzag chains connected by dmqox to form 2D-sheets containing hexagonal 18-atom fused Cu6(CN)4(dmqox)2 rings. The interwoven sheets along the a axis are close packed by extensive H-bonds developing 3D-network structure. The structures of 1 and 2 are investigated by elemental analysis IR, NMR and mass spectra. The ESI+ and ESI mass spectra of 2 support its polymeric nature while the ESI+ mass spectrum confirms the expected M. W. suggested by elemental analysis. The 13C-NMR spectrum of 2 supports the fact that the network structure of 2 contains the rhombic [Cu23-CN)2] motif. The structure of 2 was compared with the structure of the reported prototype 3 [ \textCu 2 ( \textCN ) 4 ·( \textPh 3 \textSn ) 2 ·\textqox ] ^{ 3}_{\infty } \left[ {{\text{Cu}}_{ 2} \left( {\text{CN}} \right)_{ 4} \cdot \left( {{\text{Ph}}_{ 3} {\text{Sn}}} \right)_{ 2} \cdot {\text{qox}}} \right] as well as the other related structures.  相似文献   

2.
Mixed micellization behavior of dimeric cationic surfactants ethanediyl-1,2-bis(dimethyl alkyl ammonium bromide) (m-2-m where m = 10, 12) with conventional single chain cationic surfactants like cetyltrimethyl ammonium bromide (CTAB), cetylpyridinium chloride (CPC), tetradecyl dimethyl benzyl ammonium chloride (C14BCl) and cetyl dimethyl benzyl ammonium chloride (C16BCl) were studied in aqueous and aqueous polyethylene glycol (PEG) solutions at 298.15, 308.15 and 318.15 K respectively using conductometric and viscometric methods. In aqueous solutions, all the combinations (except 12-2-12 + CTAB) were found to behave nonideally with mutual synergism which decreases with increase in temperature. Various thermodynamic parameters of micellization like \UpdeltaG\textm\texto {{\Updelta}}G_{\text{m}}^{\text{o}} , \UpdeltaH\textm\texto {{\Updelta}}H_{\text{m}}^{\text{o}} and \UpdeltaS\textm\texto {{\Updelta}}S_{\text{m}}^{\text{o}} were evaluated and discussed. Similarly in presence of PEG, the thermodynamic properties like \UpdeltaG\textt\texto {{\Updelta}}G_{\text{t}}^{\text{o}} , \UpdeltaH\textt\texto {{\Updelta}}H_{\text{t}}^{\text{o}} and \UpdeltaS\textt\texto {{\Updelta}}S_{\text{t}}^{\text{o}} associated with the transfer of surfactant monomers from the medium consisting of polymer-free mixed micelles to polymer-bound mixed micelles at various temperatures were also calculated. The negative values of \UpdeltaH\textt\texto {{\Updelta}}H_{\text{t}}^{\text{o}} show that aggregation process is more exothermic than micellization whereas the negative values of \UpdeltaS\textt\texto {{\Updelta}}S_{\text{t}}^{\text{o}} indicate that the presence of polymer bound mixed micelles decreases the degree of randomness of the system. Viscosity studies show that in aqueous solutions all the combinations of 10-2-10/12-2-12 display negative departure in the relative viscosity (ηr) from additivity rule which decreases with increase in temperature. Similarly in the presence of 5% PEG solutions the magnitude of the negative departure decreases for all the combinations and becomes positive in the case of C14BCl and CPC combinations with the studied gemini surfactants at higher temperatures.  相似文献   

3.
Two new organic–inorganic hybrid compounds [\textCu\textI ( \texten ) 2 ( \textH 2 \textO )] 2 { ( \textSiW\textVI 1 1 \textW\textV 1\textO 40 ) 2 [ \textCu\textII ( \texten ) 2 ( \textH 2 \textO )] 2 [\textCu\textII ( \texten ) 2 ] 2 }·6 \textH 2 \textO [{\text{Cu}}^{\text{I}} \left( {\text{en}} \right)_{ 2} \left( {{\text{H}}_{ 2} {\text{O}}} \right)]_{ 2} \left\{ {\left( {{\text{SiW}}^{\text{VI}}_{ 1 1} {\text{W}}^{\text{V}}_{ 1}{\text{O}}_{ 40} } \right)_{ 2} \left[ {{\text{Cu}}^{\text{II}} \left( {\text{en}} \right)_{ 2} \left( {{\text{H}}_{ 2} {\text{O}}} \right)\left] {_{ 2} } \right[{\text{Cu}}^{\text{II}} \left( {\text{en}} \right)_{ 2} } \right]_{ 2} } \right\}{\cdot}6 {\text{H}}_{ 2} {\text{O}} (1) and (H2 L)2[SiW12O40]·H2O (2) [en = ethylenediamine, L = 1,4-bis(3-pyridinecarboxamido)benzene], have been hydrothermally synthesized and characterized by IR, elemental analyses, TG analysis, and single-crystal X-ray diffraction. Structural analyses indicate that compound 1 exhibits an interesting three-dimensional(3D) cross-like supramolecular network through arrangement of a 1D organic–inorganic hybrid chain { ( \textSiW\textVI 1 1 \textW\textV 1 \textO 40 ) 2 [ \textCu\textII ( \texten ) 2 ( \textH 2 \textO )] 2 [\textCu\textII ( \texten ) 2 ] 2 } 2- . \left\{ {\left( {{\text{SiW}}^{\text{VI}}_{ 1 1} {\text{W}}^{\text{V}}_{ 1} {\text{O}}_{ 40} } \right)_{ 2} \left[ {{\text{Cu}}^{\text{II}} \left( {\text{en}} \right)_{ 2} \left( {{\text{H}}_{ 2} {\text{O}}} \right)\left] {_{ 2} } \right[{\text{Cu}}^{\text{II}} \left( {\text{en}} \right)_{ 2} } \right]_{ 2} } \right\}^{ 2- } . The compound 2 consists of protonated L ligand and [SiW12O40]4− anion. The protonated L ligands have been extended into a 2D network via hydrogen-bonding interactions. The guest [SiW12O40]4− clusters have been incorporated into the square voids of the 2D host network as templates. The electrochemical behavior and electrocatalysis of compound 2 bulk-modified carbon paste electrode (2-CPE) have been studied.  相似文献   

4.
The primary objective of modifying cotton fabric was to impart bactericidal properties to attract various fields such as defence, space and textile industrial applications. Chemically initiated graft copolymerization of 4-vinyl pyridine (4-VP) and acrylonitrile (AN) onto cotton fabric was carried out using ceric ammonium nitrate as a redox initiator. Optimum conditions pertaining to maximum percentage of grafting were evaluated as a function of concentration of initiator [CAN], concentration of nitric acid, monomer concentration, water, temperature and reaction time. Maximum grafting of 4-VP (51.63%) and AN (69.23%) was obtained respectively at optimum [ \textCAN ] = 2.738 ×10 - 2 \left[ {\text{CAN}} \right] = 2.738 \times {10^{ - 2}} and 2.19 × 10−2 moles/L, [ 4 - \textVP ] = 47.55 ×10 - 22\textmoles/\textL \left[ {4 - {\text{VP}}} \right] = 47.55 \times {10^{ - 22}}{\text{moles}}/{\text{L}} , [ \textAN ] = 18.85 ×10 - 22\textmoles/\textL \left[ {\text{AN}} \right] = 18.85 \times {10^{ - 22}}{\text{moles}}/{\text{L}} , [ \textHN\textO3 ] = 11.9 ×10 - 2 \left[ {{\text{HN}}{{\text{O}}_3}} \right] = 11.9 \times {10^{ - 2}} and 89.5 × 10−22 moles/L in 20 and 25 ml of water at an optimum temperature 70 °C and 60 °C with in 180 and 120 min. Antibacterial properties were induced into the modified cotton fabric by treating the grafted fabric with benzyl chloride. The grafted and quaternized copolymer were characterized by FTIR and Thermogravimetrical analysis. The bactericidal action of cotton fabric was tested by filtration test and it was observed that fabric grafted with 4-VP was more effective and efficient antibacterial as compared to AN grafted cotton sample.  相似文献   

5.
12-Tungstophosphoric acid supported on montmorillonite K10 (PWA/mont-K10) catalysed Pechmann condensation reaction was reported. The catalyst was characterized by XRD, FTIR, UV–Vis DRS, surface area and pore size analysis, TGA and acidity by DRIFTS using pyridine. The morphology of the catalyst was studied by SEM. The activity of mont-K10, mont-KSF, \textSO 4 2 - \mathord
/ \vphantom \textSO 4 2 - \textZrO 2 \textZrO 2 {{{\text{SO}}_{ 4}^{{ 2 {-}}} } \mathord{\left/ {\vphantom {{{\text{SO}}_{ 4}^{{ 2 {-}}} } {{\text{ZrO}}_{ 2} }}} \right. \kern-\nulldelimiterspace} {{\text{ZrO}}_{ 2} }} , 12-tungstophosphoric acid, and PWA/mont-K10 was investigated by condensation reaction of resorcinol with ethyl acetoacetate in the absence of solvent. Effect of molar ratio, amount of catalyst, reaction temperature and time on the yield of 7-hydroxy-4-methylcoumarin had been investigated on PWA/mont-K10. PWA/mont-K10 catalysed condensation of ethyl acetoacetate with phenol and a few substituted phenols had also been carried out to yield corresponding coumarins. The recycled catalyst showed reduced activity after single use. 15 wt% PWA on mont-K10 was found to be effective for synthesis of coumarin derivatives without employing any solvent.  相似文献   

6.
The non-protein amino acid, L-3,4-dihydroxyphenylalanine (L-DOPA), is the main allelochemical released from the roots of velvetbean and affects seed germination and root growth of several plant species. In the work presented here, we evaluated, in soybean roots, the effects of L-DOPA on the following: polyphenol oxidase (PPO), superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities; superoxide anion ( \textO2·- ) \left( {{\text{O}}_2^{{\bullet - }}} \right) , hydrogen peroxide (H2O2), and melanin contents; and lipid peroxidation. To this end, 3-day-old seedlings were cultivated in half-strength Hoagland’s solution (pH 6.0), with or without 0.1 to 1.0 mM L-DOPA in a growth chamber (at 25°C, with a light/dark photoperiod of 12/12 hr and a photon flux density of 280 μmol m−2 s−1) for 24 hr. The results showed that L-DOPA increased the PPO activity and, further, the melanin content. The activities of SOD and POD increased, but CAT activity decreased after the chemical exposure. The contents of reactive oxygen species (ROS), such as \textO2·- {\text{O}}_2^{{\bullet - }} and H2O2, and the levels of lipid peroxidation significantly decreased under all concentrations of L-DOPA tested. These results suggest that L-DOPA was absorbed by the soybean roots and metabolized to melanin. It was concluded that the reduction in the \textO2·- {\text{O}}_2^{{\bullet - }} and H2O2 contents and lipid peroxidation in soybean roots was due to the enhanced SOD and POD activities and thus a possible antioxidant role of L-DOPA.  相似文献   

7.
Three fluorinated cationic surfactants were prepared by condensing N-methyl diethanol amine pentafluoro benzoate with stoichiometric amounts of octyl, dodecyl or hexadecyl bromide. The surface properties and parameters were investigated to find the relationship between the structures of the hydrophobic portion of such compounds. The properties studied include surface tension, critical micelle concentration (CMC), effectiveness (Πcmc), maximum surface excess (Γmax) and minimum surface area (Amin) were investigated with respect to different concentrations at 25 °C. Standard free energies of micellization and adsorption of the prepared surfactants in the aqueous solution were studied. The values of Γmax, standard free energies of micellization \Updelta \textG\textmic\texto \Updelta {\text{G}}_{\text{mic}}^{\text{o}} and adsorption \Updelta \textG\textads\texto \Updelta {\text{G}}_{\text{ads}}^{\text{o}} were found to increase with the chain length, while the cmc and minimum surface area occupied by one molecule Amin were found to decrease. The biocidal activity was determined through the inhibition zone diameter of prepared compounds which were measured against five strains of a representative group of microorganisms.  相似文献   

8.
Synthesis and Properties of Novel Alkyl Sulfonate Gemini Surfactants   总被引:2,自引:0,他引:2  
A series of novel dialkyl disulfonate gemini surfactants (2Cn-SCT where n is the carbon number of the hydrophobic chain) were synthesized from cyanuric chloride, aliphatic amine and taurine. The chemical structures of the prepared compounds were confirmed by 1H NMR, 13C NMR, IR spectra, and ESI–MS. Their critical micelle concentrations (CMC) in the aqueous solutions at 25 °C were determined by surface tension and electrical conductivity methods. With the increasing length of the carbon chain, the values of their CMC initially decreased, and then increased with an alkyl chain length of 14. The surface tension measurements of 2Cn-SCT (except for n = 14) determined that there is a low CMC, a great efficiency in lowering the surface tension, and a strong adsorption at the air–water interface. In addition, adsorption and micellization behavior of 2Cn-SCT were estimated from pC 20, the minimum average area per surfactant molecule (A min), and standard free energy micellization and adsorption ( \Updelta G\textmic°  \textand \Updelta G\textads° \Updelta G_{\text{mic}}^{^\circ } \,{\text{and}}\,\Updelta G_{\text{ads}}^{^\circ } ). These properties are significantly influenced by the chain length n, and the adsorption is promoted more than the micellization.  相似文献   

9.
The reactions of K3[Cu(CN)4], R3SnCl and bipodal ligands, where R = (n-Bu)3SnCl and L = quinoxaline (qox) and R = Me3SnCl and L = quinazoline (qaz) afford the red needle crystals of 3 [ \textCu2 ( \textCN )2 m\text-(qox) ]2 {}_{\infty }^{3} \left[ {{\text{Cu}}_{2} \left( {\text{CN}} \right)_{2} \mu {\text{-(qox)}}} \right]_{2} , 1 and the orange needle crystals of [Cu2(CN)2μ(qaz)]n, 2. 1 was subjected to single crystals X-ray study while 2 was investigated by IR, 1H NMR and mass spectra as well as TGA. The crystal structure of 1 exhibits puckered CuCN chains connected by qox molecules forming 2D-sheets. The 2D-sheets contain hexagonal nets stacked in A···A···A fashion. The paralleled sheets are close packed via extensive H-bonds, π–π stacking, strong Cu-Cu interaction and short Cu–C contacts which develop 3D-network. Unique rhombic [Cu23-CN)2] motifs result as consequence of interwoven of the 2D-sheets. The structure of 2 exhibits different XRPD pattern than that of 1 although, the two structures have the same Cu:CN:L stoichiometric ratio. The emission spectra of 1 and 2 display bands around 390, 420 and 475 nm corresponding to MC transition, 1(n,π*) → So and MLCT, respectively. Thus, 1 and 2 can be considered as examples of room-temperature luminescent Cu-containing polymers which can be used in applications as molecular sensing systems. Also, the oxidative degradation of Metanil Yellow (MY) dye has been investigated by hydrogen peroxide catalyzed by 1 or 2. The catalytic activity of 1 is more pronounced than that of 2.  相似文献   

10.
A new complex of the Keggin trilacunary polyoxomolybdate (PMo9) with Fe3+ ions, having the formula (PFe3Mo9), has been synthesized and characterized by chemical analysis, FT-IR, Raman, UV-VIS-NIR and EPR spectroscopy, as well as by magnetic susceptibility measurements. Cyclic voltammetry performed at different scan rates, pH and supporting electrolyte composition, was used to investigate the electrochemical behaviour of the PFe3Mo9 complex in acidic medium and its electrocatalytic effect on H2O2 reduction. The voltammetric waves were assigned, and the enhanced electrocatalytic efficiency of PFe3Mo9 relative to PMo9 was attributed to the presence of Fe atoms.  相似文献   

11.
A complex with the formula [CuL(H2O)2]{[CuL][Fe(CN)6]}2·2H2O, where L=3,10-bis(2-hydroxyethyl)-1,3,5,8,10,12-hexaazacyclotetradecane, has been synthesized and crystallographically characterized. The structure is composed of a one-dimensional zigzag chain of $\left\{ {[{\text{CuL}}][{\text{Fe(CN)}}_{\text{6}} ]} \right\}_2^{2 - } $ units, and [CuL(H2O)2]2+ units. The one-dimensional zigzag chain extents through ${\text{Cu}}{\kern 1pt} - {\kern 1pt} {\text{CN}} - {\kern 1pt} {\text{Fe}}{\kern 1pt} - {\kern 1pt} {\text{CN}} - {\kern 1pt} {\text{Cu}}$ linkages. The adjacent two polymer chains are linked by the ${\text{O}}{\kern 1pt} - {\kern 1pt} {\text{H}}{\kern 1pt} \cdot \cdot \cdot {\kern 1pt} {\text{N}}{\kern 1pt} \equiv {\kern 1pt} {\text{C}}{\kern 1pt} - $ hydrogen bonding between [CuL(H2O)2]2+ and [Fe(CN)6]3?, forming a 3D supramolecular structure with inner hydrophilic channels. Magnetic susceptibility measurements show no exchange interaction between the Cu(II) and Fe(III) ions due to the longer ${\text{Cu}}{\kern 1pt} - {\kern 1pt} {\text{N}}$ (axial) bond length.  相似文献   

12.
The electrical conductivity was investigated for a section of the molten ternary mixture Na3AlF6-Li3AlF6-AlF3 with molar ratio n(Li3AlF6):n(AlF3) = 1 : 2. The conductivity of this system can be described by the following equation: where (i) represent the mole fractions of the additions. The influence of additions of CaF2, MgF2 and/or Al2O3 on the electrical conductivity of the binary system Na3AlF6-Li3AlF6 and the ternary system Na3AlF6-Li3AlF6-AlF3 was also studied.  相似文献   

13.

Abstract  

The kinetics of ammonia oxidation with oxygen over a Rh(110) surface were studied in the pressure range 10−5–10−4 mbar. Nitrogen was found to be the preferred product at low partial pressures ratios \textp\texto 2 :\textp\textNH 3 {\text{p}}_{{{\text{o}}_{ 2} }} :{\text{p}}_{{{\text{NH}}_{ 3} }} , while the NO pathway was favored with oxygen rich gas mixtures and at high temperature. The reactive sticking coefficient of O2 reaches up to 0.05 under steady state conditions. Pronounced hysteresis effects in the reaction rates were found in T-cycling experiments. Sustained oscillations in the reaction rates occurred under isothermal conditions at T = 620 K at a total pressure of 4 × 10−5 mbar.  相似文献   

14.
Electrospinning technique was used to prepare $ {\text{PVP}}/\left[ {{\text{Y}}\left( {{\text{NO}}_{ 3} } \right)_{ 3} + {\text{Yb}}\left( {{\text{NO}}_{ 3} } \right)_{ 3} + {\text{Er}}\left( {{\text{NO}}_{ 3} } \right)_{ 3} + {\text{Al}}\left( {{\text{NO}}_{ 3} } \right)_{ 3} } \right] $ composite nanobelts and novel structures of Y3Al5O12:Er3+, Yb3+ (denoted as YAG:Er3+, Yb3+ for short) nanobelts have been successfully fabricated after calcination of the relevant composite nanobelts at 900 °C for 8 h. YAG:Er3+, Yb3+ nanobelts were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and fluorescence spectroscopy. XRD analysis indicated that YAG:Er3+, Yb3+ nanobelts were cubic in structure with space group Ia3d. SEM analysis and histograms revealed that the width of YAG:Er3+, Yb3+ nanobelts was ca. 1.8 ± 0.37 μm under the 95 % confidence level, and the thickness was ca. 81.8 nm. Up-conversion emission spectra analysis manifested that YAG:Er3+, Yb3+ nanobelts respectively emitted strong green and red emissions centering at 522, 554 and 648 nm under the excitation of a 980-nm diode laser. The green emissions were assigned to the energy levels transitions of $ ^{ 2} {\text{H}}_{ 1 1/ 2} ,^{ 4} {\text{S}}_{ 3/ 2} \to^{ 4} {\text{I}}_{ 1 5/ 2} $ of Er3+ ions, and the red emission originated from the energy levels transition of $ ^{ 4} {\text{F}}_{ 9/ 2} \to ^{ 4} {\text{I}}_{{{\text{l5}}/ 2}} $ of Er3+ ions. The up-conversion luminescence of YAG:Er3+, Yb3+ nanobelts doped with various concentrations of Yb3+ and Er3+ was studied and the optimum molar ratio of Yb3+ to Er3+ was found to be 15:1. CIE analysis demonstrated that color-tuned luminescence can be obtained by adjusting doping concentrations of Yb3+ and Er3+ ions, which could be applied in the fields of optical telecommunication and optoelectronic devices. The up-conversion luminescent mechanism and the formation mechanism of YAG:Er3+, Yb3+ nanobelts were also proposed.  相似文献   

15.
We investigated endogenous plant hormones and needle growth in Pinus tabulaeformis plants grown in open-top chambers and exposed to ambient or elevated concentrations of carbon dioxide (CO2) and/or ozone (O3). Exposure to elevated CO2 for 100 days significantly increased the change in fresh needle weight, indole-3-acetic acid (IAA), isopentenyl-adenosine (iPA), and dihydrozeatin riboside (DHZR) content. Abscisic acid (ABA) content decreased, and no effect was observed on zeatin riboside (ZR) content or changes in needle dry weight. The ratios of IAA/ABA and total cytokinins (CKs)/ABA ( \textZR + \textDHZR + \textiPA/\textABA ) \left( {{\text{ZR}} + {\text{DHZR}} + {\text{iPA}}/{\text{ABA}}} \right) were increased. Elevated O3 significantly decreased IAA and ZR, and decreased the ratios of IAA/ABA and CKs/ABA. Ozone treatment increased ABA content but did not change iPA or DHZR content or change fresh or dry needle weights. The combination treatment significantly increased ABA content and the IAA/ABA ratio but decreased the total CKs/ABA ratio and had no effect on CKs or IAA content or change in fresh and dry needle weights. The results indicate that elevated CO2 ameliorated the effects of elevated O3 on tree growth.  相似文献   

16.
A complex with the formula [CuL(H2O)2]{[CuL][Fe(CN)6]}2·2H2O, where L=3,10-bis(2-hydroxyethyl)-1,3,5,8,10,12-hexaazacyclotetradecane, has been synthesized and crystallographically characterized. The structure is composed of a one-dimensional zigzag chain of units, and [CuL(H2O)2]2+ units. The one-dimensional zigzag chain extents through linkages. The adjacent two polymer chains are linked by the hydrogen bonding between [CuL(H2O)2]2+ and [Fe(CN)6]3–, forming a 3D supramolecular structure with inner hydrophilic channels. Magnetic susceptibility measurements show no exchange interaction between the Cu(II) and Fe(III) ions due to the longer (axial) bond length.  相似文献   

17.
A new type analog memory cell with variable output voltage has been proposed and its performance examined. The cell construction is $$\begin{gathered} {\text{Ag|RbAg}}_{\text{4}} {\text{I}}_{\text{5}} {\text{|(Ag}}_{\text{2}} {\text{Se)}}_{{\text{0}} \cdot {\text{925}}} {\text{(Ag}}_{\text{3}} {\text{PO}}_{\text{4}} {\text{)}}_{{\text{0}} \cdot {\text{075}}} {\text{|RbAg}}_{\text{4}} {\text{I}}_{\text{5}} {\text{|Ag}} \hfill \\ {\text{ }} \uparrow \hfill \\ {\text{ Pt}} \hfill \\ \end{gathered} $$ in which (Ag2Se)0.925(Ag3PO4)0.075 is a mixed conductor exhibiting high ionic and electronic conductivity at room temperature. The potential difference between the silver electrode and the platinum electrode depends on the silver activity in the mixed conductor, and it is changed by passing the current between one silver electrode and the platinum electrode. The output voltage of the cell is changed in the range of 150 to 0 mV. At open circuit, the memorized cell voltage decreased by only 1% over several hours.  相似文献   

18.
Coupling winter small grain cover crops (CC) with manure (M) application may increase retention of manure nitrogen (N) in corn (Zea mays L.), -soybean [Glycine max (L.) Merr], cropping systems. The objective of this research was to quantify soil N changes after application of liquid swine M (Sus scrofa L.) at target N rates of 112, 224, and 336 kg N ha−1 with and without a CC. A winter rye (Secale cereale L.)-oat (Avena sativa L.) CC was established prior to fall M injection. Surface soil (0–20 cm) inorganic N concentrations were quantified every week for up to 6 weeks after M application in 2005 and 2006. Soil profile (0–120 cm in 5, 20-cm depth increments) inorganic N, total N, total organic carbon and bulk density were quantified for each depth increment in the fall before M application and before the CC was killed the following spring. Surface soil inorganic N on the day of application averaged 318 \textmg  \textN  \textkg - 1\textsoil 318\,{\text{mg}}\;{\text{N}}\;{\text{kg}}^{ - 1}{_{\text{soil}}} in 2005 and 186 \textmg  \textN  \textkg - 1\textsoil 186\,{\text{mg}}\;{\text{N}}\;{\text{kg}}^{ - 1}{_{\text{soil}} } in 2006 and stabilized at 150 \textmg  \textN  \textkg - 1\textsoil 150\,{\text{mg}}\;{\text{N}}\;{\text{kg}}^{ - 1}{_{\text{soil}}} in both years by mid-November. Surface soil NO3-N concentrations in the M band were more than 30 times higher in the fall of 2005 than in 2006. The CC reduced surface soil NO3-N concentrations after manure application by 32% and 67% in mid- November 2005 and 2006, respectively. Manure applied at 224 kg N ha−1 without a CC had significantly more soil profile inorganic-N (480 kg N ha−1) in the spring after M application than manured soils with a CC for the 112 (298 kg N ha−1) and 224 (281 kg N ha−1) N rates, and equivalent inorganic N to the 336 (433 kg N ha−1) N rate. These results quantify the potential for cover crops to enhance manure N retention and reduce N leaching potential in farming systems utilizing manure.  相似文献   

19.
The metal iodides reduce partially the host coordination polymer of the type $ ^{ 3}_{\infty } \left[ {\left( {{\text{Me}}_{ 3} {\text{Sn}}} \right)_{ 3} {\text{Fe}}\left( {\text{CN}} \right)_{ 6} } \right] $ , I, to give new host–guest supramolecular coordination polymers (SCP). The physical and chemical characteristics of the new products were studied by elemental analyses, X-ray powder diffraction, IR, UV/Vis, and solid state NMR spectra. The host–guest SCP are [Mx(Me3Sn)3Fe(1–x)IIIFe x II (CN)6]n M = Li+·2H2O, 1; Li+, 2; Na+, 3; K+, 4; Cu+, 5, [Li(Me3Sn)3FeII(CN)6]n, 6 and [(LiDEE)0.9(Me3Sn)3Fe o.1 III Fe o.9 II (CN)6]n, 7. The stoichiometry and nature of the guest depend on the type of the metal iodide and the reaction conditions. The polymeric nature of these SCP is due to the presence of trigonal bipyramidal configured structure which bridges between the single d-transition metal ions. The host–guest SCP containing the Li ions have been tested as electrodes to construct four different lithium-ion batteries.  相似文献   

20.
Spectral convertors are promising materials for solar cells as they engineered the band gap necessary for suppressing the losses. Existing spectral convertors have small stokes shift which exerts re-absorption losses due to the overlap of spectrum and limits light catching ability. Here we present large stoke shift chromium doped rhombohedral Al2O3: Cr3+ as a spectral convertor from UV–VIS to red region as single doped with maximum coverage of solar spectrum in UV region. The large stoke shifts in red region around 694 nm originate from 2Eg to 4A2g and broad absorption originates from \(^{{\text{4}}}{{\text{A}}_{{\text{2g}}}}{ \to ^{\text{4}}}{{\text{T}}_{{\text{1g}}}},{{\text{ }}^{\text{4}}}{{\text{A}}_{{\text{2g}}}}{ \to ^{\text{4}}}{{\text{T}}_{{\text{2g}}}}\). This broad absorption (300–600 nm) and large stokes shift emission at 694 nm suggest that the Cr3+ dopant rhombohedral Al2O3 is well suited as spectral convertors for enhancing the efficiency of the solar cell through better matching of spectral response with spectral distribution of light striking on the solar cell.  相似文献   

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