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81.
Benzophenone analog 3 has been synthesized and characterized by the X-ray diffraction (XRD) method. The compound crystallizes in a monoclinic space group P21/c with cell parameters a = 7.701(8) Å, b = 7.151(5) Å, c= 28.323(3) Å, = 104.639(4)°, Z = 4. The structure exhibits intra- and intermolecular hydrogen bonding of the type N–HO, C–HO, and N–HN. The molecules are interlinked through hydrogen bonds forming an infinite chain. This polymeric-like structure may play an important role in biological activity.  相似文献   
82.
The performance of infrared (2.94 microm) and ultraviolet (337 nm) lasers were compared for analysis of purified spores of B. subtilis, B. cereus and B. globigii on a four-inch end-cap reflectron time-of-flight instrument. Infrared matrix-assisted laser desorption/ionization (IR-MALDI) mass spectra of these microorganisms displayed a larger number of biomarker peaks above m/z 4000, compared with UV-MALDI. Biomarker peaks were observed at higher m/z values with the IR laser.  相似文献   
83.
Prasad S  Zhang X  Ozkan CS  Ozkan M 《Electrophoresis》2004,25(21-22):3746-3760
We present a novel sensing scheme for detecting the effects of unburned fossil fuels by integrating microarray technology and dielectrophoresis to develop single-neuron arrays. These arrays have the capability to sense and identify the two fuels, at parts per billion (ppb) concentrations, as well to determine the associated physiological changes at the single-cell level. Identification is achieved through frequency domain analysis of the measured changes to the extracellular electrical activity due to the effect of the fossil fuels. This yields unique electrical identifiers known as "signature patterns". Simultaneous optical visualization to the physiological changes is obtained by specific fluorescent staining. The correlation between the signature patterns and the cellular biological behavior establishes the veracity of this identification technique.  相似文献   
84.
A quantitative, computer processed spectroscopic study, using photon counting, on the first excited triplet and singlet states of dilute isotopic mixed crystals of naphthalene at 2 K is presented for C10H8; 1-DC10H7; 2-DC10H7; 1,4-D2C10H6; 1,4,5-D3C10H5; 1,4,5,8-D4C10H4; 1,2,4,5,8-D5C10H3; a β-D4C10H4 and a β2-D6C10H2 as guests in C10D8 host crystals (and, for comparison, also for the same guests in a durene host crystal). The guest—host relative polarization Rashba formula has been verified quantitatively, and, as an added bonus, the elusive polarization ratio of the pure naphthalene crystal singlet Davydov components has been found to be 80 ± 20 (b/a), which is in poor agreement with the transition octupole—transition octupole model. The experimental guest energies and their concomitant quasiresonance shifts for bound singlet states (as well as the occurrences of unbound states) are in excellent quantitative agreement (about 1 cm?1) with those calculated using a Green's function formalism based on the ideal mixed crystal approximation and on a restricted Frenkel type dispersion relation derived from resonance pairs. The same Green's function also accounts quantitatively (within 10%) for the guest singlet state exciton localizations (guest excitation amplitudes). The triplet exciton state reveals an orientational site splitting (about 0.7 cm?1) for the 0—0 transition of the I-DC10H7 guest in C10D8 host. The order of the α and β substituted deuteronaphthalenes in the triplet state is reversed from that of the singlet state. The last two observations are related to the different nature of the lowest Π-Π* singlet and triplet states of naphthalene.  相似文献   
85.
Transparent glasses of various compositions in the system (100−x)Li2B4O7x(SrO-Bi2O3-Nb2O5) (where x=10, 20, 30, 40, 50 and 60, in molar ratio) were fabricated via splat quenching technique. The glassy nature of the as-quenched samples was established by differential thermal analyses. X-ray powder diffraction (XRD) and transmission electron microscopic studies confirmed the amorphous nature of the as-quenched and crystallinity in the heat-treated samples. Fluorite phase formation prior to the perovskite SrBi2Nb2O9 phase was analyzed by both the XRD and high-resolution transmission electron microscopy. Dielectric and the optical properties (transmission, optical band gap and Urbach energy) of these samples have been found to be compositional dependent. Refractive index was measured and compared with the values predicted by Wemple-Didomemenico and Gladstone-Dale relations. The glass nanocomposites comprising nanometer-sized crystallites of fluorite phase were found to be nonlinear optic active.  相似文献   
86.
IR spectra in the 'Finger Print' spectral range has great importance in qualitative and quantitative analysis of explosives like trinitrotoluene (TNT) and cyclotrimethyltrinitramine (RDX). Highly resolved IR bands of these compounds have been recorded in the 9.6 and 10.6 microm regions of CO2 laser. TNT and RDX are large molecules each having 21 atoms and it is very difficult to assign the modes of vibrations by comparison with those in other molecules making the vibrational assignments of observed bands a difficult task. The ab initio quantum chemical calculation is used for determining the molecular geometries and modes of vibration of these molecules with a view to assign their normal modes in the high resolution vibrational photoacoustic spectra. These assignments are very reliable in view of the good agreement between the observed and calculated frequencies of deuterated TNT.  相似文献   
87.
Synthesis and photochemistry of several title compounds 1-3 containing multiple chromophoric systems are described. The Diels-Alder reactions of 2,6,6-trimethylcyclohexa-2,4-dienone (5) with acetylenes 6a-d provided the adducts 7a-d, which upon hydrolysis furnished the desired bicyclo[2.2.2]octenediones 1a-d. Oximes 2a-d were prepared from diones 1a-d by treatment with hydroxylamine hydrochloride in pyridine. 5-Methylenebicyclo[2.2.2]oct-7-en-2-ones 3a-d were obtained via chemoselective Wittig reaction of the corresponding diones 1a-d. Bicyclo[2.2.2]octenediones 1a-c underwent chemoselective oxa-di-pi-methane rearrangement under sensitized conditions and suffered formal ketene extrusion upon direct irradiation. Direct irradiation of 1d afforded 11d via formal ketene extrusion but under sensitization it remained unchanged. Oximes 2a-d suffered ketene extrusion upon direct irradiation and E/Z isomerization under sensitized conditions. On the other hand, 5-methylenebicyclo[2.2.2]oct-7-en-2-ones 3a-d generally underwent 1,3-acyl shift. The plausible courses of all these photochemical processes are discussed.  相似文献   
88.
The title compound, [Fe2O(SO4)2(C10H8N2)4], crystallizes as two different hydrates, viz. 11H2O, (I), and 15H2O, (II). The complex is binuclear, in which the two FeIII atoms are coordinated in an octa­hedral geometry to four N atoms from the two bipyridine ligands, to one O atom from the sulfate ion and to an oxide ion on a twofold axis, which acts as a bridge between the symmetry‐related units. The Fe⋯Fe separation is 3.556 (4) Å and the Fe—O—Fe angle is 161.6 (2)° in (I); the corresponding values are 3.544 (1) Å and 165.8 (2)° in (II). In (II), one of the O atoms of the sulfate ion is disordered over two positions. In both compounds, the solvent water mol­ecules form slightly different one‐dimensional hydrogen‐bonded networks which pass along the c axis of the unit cell. In (I), three solvent water mol­ecules and, in (II), one solvent water mol­ecule, are situated on the twofold axis. In both (I) and (II), the central O atom of the metal complex lies on a twofold axis.  相似文献   
89.
The interaction between polyvinylpyrrolidone (PVP) and sodium dodecyl sulfate (SDS) after the procedure of addition of the surfactant to polymer and the reverse procedure of addition of polymer to SDS micelles has been studied by tensiometric, conductometric, and microcalorimetric methods. The results have been analyzed and correlated with reference to SDS interfacial adsorption, association, and binding to PVP. Two aggregation states of SDS in presence of PVP have been found. The enthalpies of formation of SDS aggregates/micelles and their binding to the polymer have been evaluated. The interaction of PVP with SDS at concentrations below its critical micellar concentration (CMC) and above have evidenced distinctions. The forward addition protocol (FAP, SDS addition to PVP) and reverse addition protocol (RAP, PVP addition to SDS) have shown similarities and differences. Electrokinetic measurements have evidenced the interacted (SDS–PVP) colloidal products to possess negative zeta potential in the range of −39 to −65 mV. The hydrodynamic diameters of the PVP–SDS dispersion obtained from DLS measurements have ranged between 60 and 160 nm. Both zeta potential and hydrodynamic diameter have depended on [SDS] showing a maximum for the former at twice the critical micellar concentration of SDS.  相似文献   
90.
The electrochemical and chemical polymerization of acrylamide (AA) has been studied. The electrolysis of the monomer in N,N-dimethylformamide (DMF) containing (C4H9)4NClO4 as the supporting electrolyte leads to polymer formation in both anode and cathode compartments. The cathodic polymer dissolves in the reaction mixture and the anodic polymer precipitates during the course of polymerization. A plausible mechanism for the anodic and cathodic initiation reaction has been given. The chemical polymerization of acrylamide that has been initiated by HClO4 is analogous to its anodic polymerization. The polymer yield increases with an increase in concentration of the monomer and HClO4. Raising the reaction temperature also enhances the polymerization rate. The overall apparent activation energy of the polymerization was determined to be ca. 19 kcal/mole. The copolymerization of acrylamide was carried out with methyl methacrylate (MMA) in a solution of HClO4 in DMF. The reactivity ratios are r1 (AA) = 0.25 and r2 = 2.50. The polymerization with HClO4 appears to be by a free radical mechanism. When the polymerization of acrylamide is carried out with HClO4 in H2O, a crosslinked water-insoluble gel formation takes place.  相似文献   
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