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101.
The rotational spectrum of DC5N has been investigated in the millimeter-wave region for 16 vibrationally excited states which approximately lie below 760 cm−1, namely (v6 v7 v8 v9 v10 v11)=(000001), (000002), (000003), (000005), (000010), (000020), (000100) (001000), (010000), (100000), (000011), (000101), (001001), (010001), (001010), and (010010). Gas-phase copyrolysis of fully deuterated pyridine and phosphorus trichloride was used to produce the semi-stable DC5N molecule. In addition to the usual l-type resonances, several vibrational interactions have been taken into account to fit properly the measured transition frequencies. The most important perturbations are caused by the cubic anharmonic interactions which mix the v6 stretching state with the 2v10 overtone and the v8+v11 and v7+v11 bending combination states. The analysis of the spectra was facilitated by theoretical predictions from CCSD(T) calculations with the cc-pVQZ basis. 相似文献
102.
《Polyhedron》2005,24(16-17):2405-2408
A 3He refrigerator mountable to a commercial SQUID magnetometer has been developed, which enables us to measure static magnetizations of a sample at temperatures below 2 K conveniently. The design and usage of the system are outlined. We have applied this to study static magnetic properties of an organic ferromagnet, β-p-NPNN, and have confirmed that the saturation magnetization is 1 μB per molecule. No hysteretic behavior has been detected, when the field was applied along the easy axis. This indicates that β-p-NPNN is a very soft magnet, as expected for an isotropic Heisenberg magnet based on organic radicals. 相似文献
103.
《中国化学快报》2020,31(4):922-930
MXenes have emerged as versatile 2D materials that are already gaining paramount attention in the areas of energy,catalyst,electromagnetic shielding,and sensors.The unique surface chemistry,graphene-like mo rphology,high hydrophilicity,metal-like conductivity with redox capability identifies MXenes,as an ideal material for surface-related applications.This short review summarizes the most recent reports that discuss the potential application of MXenes and their hybrids as a transducer material for advanced sensors.Based on the nature of transducing signals,the discussion is categorized into three sections,which include electrochemical(bio) sensors,gas sensors,and finally,electro-chemiluminescence fluorescent sensors.The review provides a concise summary of all the analytical merits obtained subsequent to the use of MXenes,followed by endeavors that have been made to accentuate the future perspective of MXenes in sensor devices. 相似文献
104.
Dehui Sun Hongjie Zhang Jilin Zhang Jiangbo Yu 《Journal of solid state chemistry》2007,180(1):393-399
A novel supramolecular compound 1,6-hexanediamine trimolybdate ((C6H18N2)[Mo3O10], denoted as HDAMo) has been synthesized by a hydrothermal method and its structure has been characterized by elemental analyses, Fourier transform infrared (FT-IR) spectra, single-crystal X-ray diffraction (XRD) technique. This single crystal compound consists of protonated 1,6-hexanediamine (HDA) cations and polyoxometalate [Mo3O10]2− anions. Its crystal structure belongs to monoclinic system (space group P21/n) with a=7.7508(14), b=11.467(2), c=16.167(3) Å, β=92.689(3)°, V=1435.3(5) Å3, Z=4 and Dcalc=2.619 g cm−3. The final statistics based on F2 are GOF=0.980, R1=0.0261 and wR2=0.0506 for I>2σ(I). XRD analysis revealed that in the crystal structure of HDAMo, novel infinite [Mo3O10]2− chains parallel to a axis are made up of distorted MoO6 octahedra connected by corners and edges. The protonated HDA cations occupy channels formed by [Mo3O10]2− chains and exhibit strong hydrogen bond interactions to terminal and bridging oxo groups of the chains. The [Mo3O10]2− chains linked through protonated HAD cations formed a one-dimensional network. The HDAMo compound shows novel photochromic properties, i.e., its color changes from white to reddish brown gradually under UV irradiation. XRD, FT-IR, ESR spectra and XPS are used to investigate the photochromic behavior of the compound. 相似文献
105.
A white substance was got by directly heating TiSi powder on Ti foil, under Ar+O
2 atmosphere. ED, EDX, SEM and HRTEM studies reveal that the white substance consists of amorphous SiO
2 nanowires of smooth surface and uniform diameter (40-90 nm). X-ray-induced luminescent emission experiment shows that two
broad peaks are at 430 and 570 nm. A one-dimensional growth mechanism, on the basis of the one-dimensional thermal flow during
nanowire formation, is discussed. 相似文献
106.
Richardson RA Cotton JW Mark Ormerod R 《Dalton transactions (Cambridge, England : 2003)》2004,(19):3110-3115
La(0.6)Sr(0.4)Co(0.2)Fe(0.8)O(3-delta)(LSCF) perovskite powders have been synthesised by solid-state reaction, co-precipitation, drip pyrolysis and citrate gel routes, and characterised using XRF, XRD, SEM and BET. Co-precipitation using oxalic acid or aqueous ammonia as precipitant failed to achieve the correct chemical composition. Perovskite structures were achieved in all other cases. Surface areas ranging from 0.6 to 17.4 m(2) g(-1) were obtained, which was reflected in the different microstructures observed. The citrate gel product exhibited a convoluted network morphology resulting in its large surface area. Thin-walled (approximately 200 microm) tubular membranes have been manufactured from the LSCF powders using viscous plastic processing. The tubes have been characterised using a custom-built gas analysis rig with on-line mass spectrometry. Porosity levels of the membranes were found to be very low (<0.1%). The spontaneous oxygen flux across the tubular membranes was determined as a function of temperature. Oxygen permeation rates ranged from 0.1 to 0.3 micromol cm(-2) s(-1) at 1273 K. The catalytic behaviour of the LSCF tubes towards methane oxidation has been studied using temperature programmed reaction and conventional catalytic measurements. The tubes favoured combustion reactions, with smaller amounts of partial oxidation and oxidative coupling products observed. Powder coatings have been incorporated to establish the effect of increasing surface area. 相似文献
107.
Sm, Pr掺杂CeO2和CeMoO15基固体电解质的结构与性能 总被引:1,自引:0,他引:1
采用溶胶凝胶法制备了Sm和Pr掺杂的CeO2和CeMoO15基固体电解质, 通过X射线衍射(XRD)、拉曼光谱(Raman)、场发射扫描电镜(FE-SEM)等手段对氧化物结构进行了分析, 用交流阻抗谱测试了其电性能, 并比较了不同基体及其掺杂体系的结构与电性能. 结果表明, Ce6MoO15基掺杂体系的导电性能高于CeO2基掺杂体系; 元素Mo的加入使Ce6MoO15基材料的晶粒尺寸增大, 晶界相成分减少, 材料的晶界电导率增加, 600 ℃以下材料导电性能明显提高; Pr的掺入减小了材料的晶粒尺寸, 提高了材料的晶界电导率. 相似文献
108.
《Chemical physics letters》2006,417(1-3):185-189
The effect of various reaction schemes used to convert total reaction enthalpies obtained via ab initio methods into enthalpies of formation has been studied employing a new optimization technique. The reaction schemes, conventional, isostoichiometric, and isodesmic have been defined and generated for 47 species for which highly accurate experimental enthalpies of formation in addition to total reaction enthalpies at 298 K at G2 and G3 levels of theory are known. The main finding is that the effect of reaction schemes in ab initio-based thermochemistry predictions is small, especially, for enthalpy predictions involving high-level ab initio methods. 相似文献
109.
A new catalytic kinetic spectrophotometric method has been developed for the determination of trace amount of manganese (II) in nonionic microemulsion medium. The method is based on the catalytic effect of manganese (II) on the oxidation of dahlia violet by potassium periodate with nitrilotriacetic acid as an activitor in the presence of nonionic microemulsion. Under the optimum conditions, the calibration graph is linear in the range of 0.0004-0.0056 μg ml−1 of manganese (II) at 580 nm. The detection limit achieved is 3.75×10−5 μg ml−1. Manganese (II) in foodstuff samples was determined with satisfactory results. 相似文献
110.
《Spectrochimica Acta Part B: Atomic Spectroscopy》2006,61(1):50-57
Four inductively coupled plasma mass spectrometric methods: nebulization sample introduction with external calibration; hydride generation with external calibration; isotope dilution with nebulization; and isotope dilution with hydride generation, have been tested and compared. Multimode Sample Introduction System (MSIS™) was employed in either nebulization or hydride generation mode. Best limits of detection (below 0.1 μg L− 1) and accuracy were obtained for isotope dilution techniques in hydride generation and sample nebulization mode. A mixture of HNO3 and H2O2 served both for microwave-assisted digestion as well as a medium for subsequent plumbane generation. Optimal reagent concentrations for hydride generation stage were 0.1 mol L− 1 HNO3, 0.28 mol L− 1 H2O2 and 1.5% m/v NaBH4. Critical effects of acidity, blanks and concomitants have been discussed. Analytical methods were validated by use of plant and water certified reference materials and spiked high-salt solutions (seawater and 20% m/v NaCl) at lead levels in nanograms per gram to micrograms per gram range. 相似文献