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We examined the high pressure behavior of stannous oxalate via Raman and X-ray absorption spectroscopy (XAS) inside a diamond anvil cell. Phase transitions were observed to occur near 2.6 and 15 GPa which were reversible upon decompression to ambient conditions. When further pressurized above 15 GPa, the colorless material sustains irreversible chemical alterations and becomes bright red colored – darkening at higher pressures. Another irreversible phase transition occurred above 20 GPa. Concomitant with color change of the sample, we observed a softening of the ν(C–C) modes of the C2O42− anion via Raman spectroscopy. We performed a separate XAS experiment which indicates that the Sn2+ cation undergoes a partial reduction of the 2+ oxidation state with pressure which persists when the sample was depressurized to ambient conditions. Thus, electron density within the C–C bond in the oxalate anion appears to migrate toward the tin cation with pressure. This observation suggests that pressure can offer a very controllable means to vary cation–anion and unit cell dimensions (and thus the electric interactions causing electron movement) and thus the pressure-induced synthesis of novel materials.

The carbazole moiety is a commonly identified structural motif in the high-molecular-weight components of petroleum, known as asphaltenes. Detailed characterization of carbazoles is important for understanding the structure of asphaltenes and addressing challenges in the areas of heavy oil recovery, transportation, upgrading, and oil spills, arising from asphaltene properties and composition. In this work we study carbazole and the four N-substituted carbazoles 9-methylcarbazole, 9-ethylcarbazole, 9-vinylcarbazole and 9-phenylcarbazole. Experimental far- and mid-infrared spectra of these five carbazoles are measured using transmission and photoacoustic techniques. The molecular structures of the monomers and the respective dimers, optimized at the ωB97X-D/6-311++G(d,p) level of the density functional theory (DFT), are subjected to harmonic vibrational frequency calculations. The effect of changing substituents on the N-H bond, π-π stacking distances, and angles between monomers within the dimers, in addition to intermolecular interactions, is investigated. Noncovalent interaction analysis is employed to highlight the areas of attractive and repulsive interactions in the dimers. Thermochemistry calculations show that the formation of dimers of all carbazoles is spontaneous at 298 K. Comparison of the calculated vibrational spectra of these compounds with experimental spectra indicates that the existence of both monomers and dimers must be invoked to account for the observed bands in the infrared spectra. Excellent correlations between the experimentally-determined and calculated harmonic vibrational energies are obtained, with an experimental-to-calculated scaling factor of 0.95-0.96. These findings highlight the coupled computational-experimental approach for the interpretation of vibrational spectra and are essential for improving the spectroscopic characterization of N-substituted carbazoles.

A discrepancy between theoretical and experimental values of the rotational barrier in benzaldehyde has been observed, which was attributed to inaccurate experimental results in part. Here, we report results on the -CHO torsion of benzaldehyde (C6H5CHO) based on a high resolution spectroscopic investigation in the far-infrared range in an effort to remove the experimental ambiguity. The rotationally-resolved vibrational spectra were measured with an unapodized resolution of 0.00064 cm-1 using synchrotron-based Fourier transform infrared (FTIR) spectroscopy at the Canadian Light Source. The torsional fundamental νt = 109.415429(20) cm-1 was unambiguously assigned via rovibrational analysis, followed by the tentative assignment of the first (2νt-νt) and second (3νt- 2νt) hot bands at 107.58 cm-1 and 105.61 cm-1, respectively, by comparison of the observed Q branch structures at high resolution with simulation based on a previous microwave study. This assignment is different from any previous low resolution infrared studies in which the intensity patterns were misleading. The key result of the assignment of the first three transitions allowed the determination of the barrier to internal rotation of (hc)1533.6 cm-1 (4.38 kcal mol-1). When compared with calculated results from vibrational second-order perturbation theory (VPT2) and the quasiadiabatic channel reaction path Hamiltonian (RPH) approach, the experimental value is still too low and this suggests that the discrepancy between theory and experiment remains despite the best experimental efforts.

In this work, we present the spectral analysis of 1 H- and 2 H-1,2,3-triazole vibrationally excited states alongside provisional and practical computational predictions of the excited-state quartic centrifugal distortion constants. The low-energy fundamental vibrational states of 1 H-1,2,3-triazole and five of its deuteriated isotopologues ([1-2H]-, [4-2H]-, [5-2H]-, [4,5-2H]-, and [1,4,5-2H]-1 H-1,2,3-triazole), as well as those of 2 H-1,2,3-triazole and five of its deuteriated isotopologues ([2-2H]-, [4-2H]-, [2,4-2H]-, [4,5-2H]-, and [2,4,5-2H]-2 H-1,2,3-triazole), are studied using millimeter-wave spectroscopy in the 130–375 GHz frequency region. The normal and [2-2H]-isotopologues of 2 H-1,2,3-triazole are also analyzed using high-resolution infrared spectroscopy, determining the precise energies of three of their low-energy fundamental states. The resulting spectroscopic constants for each of the vibrationally excited states are reported for the first time. Coupled-cluster vibration–rotation interaction constants are compared with each of their experimentally determined values, often showing agreement within 500 kHz. Newly available coupled-cluster predictions of the excited-state quartic centrifugal distortion constants based on fourth-order vibrational perturbation theory are benchmarked using a large number of the 1,2,3-triazole tautomer isotopologues and vibrationally excited states studied.

We examined the high pressure behavior of stannous oxalate via Raman and X-ray absorption spectroscopy (XAS) inside a diamond anvil cell. Phase transitions were observed to occur near 2.6 and 15 GPa which were reversible upon decompression to ambient conditions. When further pressurized above 15 GPa, the colorless material sustains irreversible chemical alterations and becomes bright red colored - darkening at higher pressures. Another irreversible phase transition occurred above 20 GPa. Concomitant with color change of the sample, we observed a softening of the ν(C-C) modes of the C2O42- anion via Raman spectroscopy. We performed a separate XAS experiment which indicates that the Sn2+ cation undergoes a partial reduction of the 2+ oxidation state with pressure which persists when the sample was depressurized to ambient conditions. Thus, electron density within the C-C bond in the oxalate anion appears to migrate toward the tin cation with pressure. This observation suggests that pressure can offer a very controllable means to vary cation-anion and unit cell dimensions (and thus the electric interactions causing electron movement) and thus the pressure-induced synthesis of novel materials.

With Covid-19 spreading, in order to respond to the Ministry of Education’s deployment of “suspended classes without suspension of learning”, Teachers in higher vocational colleges is also actively developing online teaching. In this paper, the Blended teaching mode of “online and offline integration” is optimized and adjusted and developed an effective online Flipped Blended mode based on SPOC. Taking the course of “digital video production” as an example, the Blended teaching mode of “Tencent classroom + vocational education cloud + QQ group” is usedto achieve real-time and efficient teaching results.

Propene infrared absorption cross-sections are important for quantitative analysis of atmospheric spectra. Propene has been observed in Titan's atmosphere and may be detected in the atmospheres of giant planets. Infrared absorption cross-sections of propene (C3H6) have been measured in the 2680–3220 cm−1 region by high-resolution Fourier transform spectroscopy. Samples of propene were held at 202, 232, 265, 295 K with helium and nitrogen broadening gas pressures of 10, 30, 100 Torr. The cross section files are available for download.

Correspondence bias (CB) refers to individuals' tendency to make trait inferences regarding the constrained behavior of others. To investigate the influences of the attitude diagnosticity of behavior and situational constraints on CB in a cross-cultural context, a sample of 357 Chinese undergraduates (140 males, 39.2%) aged 17-27 years old (

The rotational spectrum of thiazole (c-C3H3NS, Cs, μa = 1.3 D, μb = 0.97 D) from 130 to 375 GHz and high-resolution infrared spectrum from 300 to 1300 cm−1 were obtained and analyzed. Nearly 4700 new, pure-rotational transitions were measured for the ground vibrational state, as well as over 1400 transitions for each of its three lowest-energy vibrationally excited states (ν18, ν17, and ν13). A total of over 5500 rotationally resolved, infrared transitions were measured for fundamentals ν17 and ν13, which form a Coriolis-coupled dyad. Transitions for each of these vibrational states of thiazole were fit to a sextic, A-reduced Hamiltonian in the Ir representation. Computed CCSD(T) values of the spectroscopic constants of thiazole show remarkable agreement with the experimentally determined values. Deuterium enrichment of thiazole allowed for the observation of the ground state and first fundamental (ν18) for three isotopic thiazoles. The direct impact on ν18 by isotopic substitution at C2 and C5 is observed. The combined rotational and high-resolution IR data allowed for an excellent fit of the Coriolis-coupled dyad of ν17 and ν13, which includes more than 60 nominal interstate transitions. Some of the measured resonant transitions are displaced by more than 30 GHz. The least-squares fit yielded six Coriolis coupling terms ( G a , G a J , G a K , G b , G b J , and G b K ) and very accurate measurements of the ν17 and ν13 band origins, 603.8511589 (17) cm−1 and 611.2214645 (18) cm−1, respectively. Collectively, these data provide reliable spectroscopic constants that can be used to predict the rotational spectra of thiazole up to 360 GHz.

Glycolaldehyde (GA) has been observed toward several different sources, with a broad range of rotational temperatures (8–300 K). At the high end, the temperature is comparable to the energy of the lowest vibrational states of GA, making the vibrational contribution to the partition function significant. Here, we report an analysis of the high-resolution far-infrared spectrum of GA, which features a plethora of well-resolved lines from 170–430 cm−1 (13–5 THz). We focus on the three fundamental vibrational bands in this range, i.e., the symmetric ν 12 bend at 282 cm−1, and the asymmetric ν 17 and ν 18 torsions at 360 and 208 cm−1, respectively. We assigned 23,266 transitions to 13,999 lines within these bands, which, when combined with the previously reported microwave and millimeter-wave spectra, allowed for refinement of the vibrationally excited rotational constants, and accurate determination of their band origins. Additionally, the assignment of a number of lines in several hot bands that are significantly populated at 300 K allowed for determination of their band origins. The rotational constants reported here should be useful in searches of vibrationally excited GA toward warm sources, and the accurately determined band origins allow for refinement of the vibrational partition function, and therefore column density, for a given excitation temperature.

The valence electron topologies of Mg 2 Si thermoelectric materials multi-doped with Al, Zn and Sb have been determined by the Maximum Entropy Method (MEM) using synchrotron X-ray powder diffraction data. In spite of the very low concentrations, expansion was observed in the cubic unit cells of the doped samples. Using pure Mg 2 Si as a reference, charge density difference maps revealed qualitative features on the distributions of the electrons contributed by the doped atoms. The presence of excess electrons shows all doped samples are n -type semiconductors and they are shared among the atomic sites. We evaluated the reliability of the MEM calculated charge density by considering the effect of successively increasing the number of high angle Bragg reflections used in the analysis on the diffraction pattern of a single doped Al–Mg 2 Si sample.

The infrared absorption cross sections of ethane (C2H6) have been measured in the 3.3 µm region by high resolution Fourier transform spectroscopy. The ethane samples had temperatures of 203, 233, 263, 295 K with broadening gas pressures of 10 Torr, 30 Torr and 100 Torr of hydrogen or helium. These cross sections are useful for the interpretation of spectra of the giant planets.

Infrared absorption spectra of neopentane, 2,2-dimethylpropane, C(CH3)4, were recorded in the 2550-3350 cm-1 region by high resolution Fourier transform spectroscopy at the Canadian Light Source (CLS). Absorption cross sections were obtained for pure samples and with nitrogen as a broadening gas for 4 temperatures (202, 232, 265, 297 K).

High resolution infrared absorption cross sections of isobutane, (CH3)3CH, were measured in the 1050–1900 cm−1 spectral range by Fourier transform spectroscopy. Four sample temperatures (210, 234, 265 and 296 K) were used with three pressures (10, 30 and 100 Torr) of N2 and H2 broadening gas. Spectra of pure isobutane samples were also recorded. These cross sections are useful for the interpretation of infrared spectra of the Giant Planets and Titan. The isobutane cross sections give an upper limit of 3.91e-8 for its fractional abundance on Titan based on CIRS/Cassini infrared spectra. Using n-butane, CH3(CH2)2CH3, cross sections from the literature, we obtain an upper limit of 5.13e-7 for its abundance on Titan. The combined upper limit for both isomers of butane, C4H10, on Titan of 5.52e-7 is consistent with the lower limit of recent model predictions.

Near infrared absorption spectra of ethane (C2H6) were recorded in the 1800–6200 cm−1 region by high resolution Fourier transform spectroscopy (Bruker IFS 125 HR) at the Canadian Light Source (CLS). Absorption cross sections were obtained for pure samples and with nitrogen or hydrogen as broadening gases as appropriate for astronomical environments. Corrections to the cross sections were made using data from the Pacific Northwest National Laboratory (PNNL) infrared database.

This study developed a model of blended learning based on Bring Your Own Device (BYOD), focusing on effective support for different processes of instruction and learning based on BYOD. A case study was carried out, based on the course Two-Dimensional Animation. BYOD, in this study, refers to "the technology model where students bring a personally owned mobile device with various apps and embedded features to use anywhere, anytime for the purpose of learning". The BYOD-based blended learning model was designed specifically for this course and applied to guide instructional design, evaluate its effectiveness, and explore operational strategies in detail. The results indicated that the application of the model significantly improved students' learning efficiency and initiative, promoted their application of knowledge and improved outcomes, which is of guiding significance to practice.

We investigated the effect of germanium substitution for silicon in bismuth doped Mg 2 Si. This alloying reduces the thermal conductivity from above 7 W m −1 K −1 to 2.7 W m −1 K −1 at around 300 K in part due to the added mass contrast. High resolution transmission electron microscopy (HRTEM) revealed the presence of Ge-rich domains within the Mg 2 (Si,Ge,Bi) particles, contributing to decreasing thermal conductivity with increasing Ge content up to 0.3 Ge per formula unit. The electrical conductivity also decreases with Ge alloying because of the increasing amount of scattering centers, while the Seebeck coefficient increased only very slightly. In total, the positive effect of Ge substitution on the thermoelectric properties of Bi doped Mg 2 Si resulted in a figure of merit of 0.7 at 773 K for Mg 2 Si 0.677 Ge 0.3 Bi 0.023 sample. The optimum amount of Bi seems to be 0.023 per formula unit (0.77 at%), since lower Bi content resulted in electrical conductivity that is too low, and higher Bi content generated the Mg 3 Bi 2 intermetallic phase.

Enhanced thermoelectric and electrical transport properties of Mg2Si-based thermoelectric materials have been achieved by multi-doping with Sb, Al and Zn. Results on the investigation of the electrical transport and thermoelectric properties of multi-doped samples prepared using the spark plasma sintering technique are reported. Synchrotron radiation powder X-ray diffraction was used to characterize the structures of the doped samples. The electrical transport properties were determined from mid-infrared reflectivities, Hall effect and conventional quasi-four probe conductivity measurements. Using the electron concentrations (N) determined from the Hall coefficients, the effective masses (m*) were calculated from the frequency of the plasma edge (ωP) of the infrared reflectivities. The thermoelectric performance and thermoelectric figure of merits (ZT) in the temperature range of 300 K to 900 K of the doped Mg2Si compounds were calculated from the measured temperature dependent electrical conductivity (σ), Seebeck coefficient (S), and thermal conductivity (κ). A maximum ZT of 0.964 was found for Sb0.5%Zn0.5% doped Mg2Si at 880 K. This value is comparable to those of PbTe based thermoelectric materials.

The effect of multi wall carbon nanotubes (CNT) on the thermoelectric properties of Mg2Si0.877Ge0.1Bi0.023 was examined. While introducing CNTs increases the electrical conductivity from around 450 Ω−1 cm−1 to 500 Ω−1 cm−1 at 323 K, the increase is neutralized at higher temperature, with the conductivity resulting to be 440 Ω−1 cm−1–470 Ω−1 cm−1 at 773 K. The Seebeck coefficient of all nanocomposites is enhanced at 773 K due to energy filtering that stems from the introduction of CNTs–Mg2Si0.877Ge0.1Bi0.023 interfaces. The combined effect of CNTs on Seebeck coefficient and electrical conductivity leads to an approximately 20% power factor improvement, with the best sample reaching a maximum value of ∼19 μW cm−1 K−2 at 773 K. The lattice thermal conductivity of the nanocomposites is reduced due to the phonon scattering by nanodomains and grain boundaries, particularly at medium temperatures, resulting in a slight reduction in total thermal conductivity. According to high resolution transmission electron microscopy studies, bismuth is homogenously distributed within the grains, while germanium is accumulated at the grain boundaries. All in all, the enhanced thermoelectric figure of merit of 0.67 at 773 K for the sample containing 0.5 weight% MWCNT as compared to 0.55 for the pristine sample, demonstrates the promising effect of CNTs on the thermoelectric properties of Mg2Si0.877Ge0.1Bi0.023.

Due to increasing global energy concerns, alternative sustainable methods to create energy such as thermoelectric energy conversion have become increasingly important. Originally, research into thermoelectric materials was focused on tellurides of bismuth and lead because of the exemplary thermoelectric properties of Bi2Te3 and PbTe. These materials, however, contain toxic lead and tellurium, which is also scarce and thus expensive. A viable alternative material may exist in Mg2Si, which needs to be doped and alloyed in order to achieve reasonable thermoelectric efficiency. Doping is a major problem, as p-type doping has thus far not produced competitive efficiencies, and n-type doping is problematic because of the low solubility of the typical dopants Sb and Bi. This investigation shows experimentally that these dopants can indeed replace Si in the crystal lattice, and excess Sb and Bi atoms are present in the grain boundaries in the form of Mg3Sb2 and Mg3Bi2. As a consequence, the carrier concentration is lower than the formal Sb/Bi concentration suggests, and the thermal conductivity is significantly reduced. DFT calculations are in good agreement with the experimental data, including the band gap and the Seebeck coefficient. Overall, this results in competitive efficiencies despite the low carrier concentration. While ball-milling was previously shown to enhance the solubility of the dopants and thus the carrier concentration, this did not lead to enhanced thermoelectric properties.

The crystal structure and charge transport properties of the prototypal oxobenzene-bridged 1,2,3-bisdithiazolyl radical conductor 3a are strongly dependent on pressure. Compression of the as-crystallized α-phase, space group Fdd2, to 3-4 GPa leads to its conversion into a second or β-phase, in which F-centering is lost. The space group symmetry is lowered to Pbn2₁, and there is concomitant halving of the a and b axes. A third or γ-phase, also space group Pbn2₁, is generated by further compression to 8 GPa. The changes in packing that accompany both phase transitions are associated with an "ironing out" of the ruffled ribbon-like architecture of the α-phase, so that consecutive radicals along the ribbons are rendered more nearly coplanar. In the β-phase the planar ribbons are propagated along the b-glides, while in the γ-phase they follow the n-glides. At ambient pressure 3a is a Mott insulator, displaying high but activated conductivity, with σ(300 K) = 6 × 10(-3) S cm(-1) and E(act) = 0.16 eV. With compression beyond 4 GPa, its conductivity is increased by 3 orders of magnitude, and the thermal activation energy is reduced to zero, heralding the formation of a metallic state. High pressure infrared absorption and reflectivity measurements are consistent with closure of the Mott-Hubbard gap near 4-5 GPa. The results are discussed in the light of DFT calculations on the molecular and band electronic structure of 3a. The presence of a low-lying LUMO in 3a gives rise to high electron affinity which, in turn, creates an electronically much softer radical with a low onsite Coulomb potential U. In addition, considerable crystal orbital (SOMO/LUMO) mixing occurs upon pressurization, so that a metallic state is readily achieved at relatively low applied pressure.

Decomposition on the energy consumption change, which is brought about by economic structure, departmental energy intensity and departmental activity, is benefit for making energy and economic policies. China's end energy consumption from 1991 to 2005 is divided into five end departments in the research, including industry (the construction is included), agriculture, transportation (post and telecommunication is involved), commercial services and residents' consumption. The associated activity and the structure, the energy consumption and the share, the intensity of energy consumption are analyzed. According to the Chinese macro-economic development target and the policy of energy saving, the paper forecasts different energy demands in different end energy departments in 2010 from the perspective of activity effect, intensity effect and structure effect.

The reform of Chinapsilas coal sector has changed the traditional relationship of the coal producers and electric power generators, and now most of the coal the coal producers sell to the generators is transacted through electric coal bilateral contracts, whose price is negotiated in advance. However, long time and low efficiency always come along with the negotiation process, so in this paper, the agent-based negotiation environment was designed for the negotiators so as to reduce the negotiation time, and a Bayesian learning model is designed to enhance the negotiator agentpsilas adjust ability to the dynamic environment. The final example proved that the Bayesian learning model can help the agent obtain more accurate information about its opponent through the negotiation process and bid more efficiently, so the negotiation time is reduced and its efficiency is improved.

A recent study has shown the thermoelectric performance of Al-doped Mg2Si materials can be significantly enhanced at moderate pressure. To understand the cause of this phenomenon, we have performed in situ angle dispersive X-ray diffraction and infrared reflectivity measurements up to 17 GPa at room temperature. Contrary to previous experiment, using helium as a pressure transmission medium, no structural transformation was observed in pure Mg2Si. In contrast, a phase transition from cubic anti-fluorite (Fm-3m) to orthorhombic anti-cotunnite (Pnma) was observed in the Al-doped sample at 10 GPa. Infrared reflectivity measurements show the electrical conductivity increases with pressure and is further enhanced after the phase transition. The electron density of states at the Fermi level computed form density functional calculations predict a maximum thermoelectric power factor at 1.9 GPa, which is in good agreement with the experimental observation.

Following the development of high brilliance synchrotron x-ray sources, high density crystalline structures of elemental solids have been vastly studied at room temperature and elevated pressures. In the last decades, experimental and computational results have unveiled a vast diversity of crystalline structures adopted by many dense elements. Both complex modulated and exotic structures have been observed [1] and predicted [2]. In this communication, we report results of systematic searches for structural modifications taking place at very low temperature (T>10 K) and high pressure (P