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991.
Danillo Valverde Adalberto V. S. de Araújo Antonio Carlos Borin 《Molecules (Basel, Switzerland)》2021,26(17)
The photophysical relaxation mechanisms of 1-cyclohexyluracil, in vacuum and water, were investigated by employing the Multi-State CASPT2 (MS-CASPT2, Multi-State Complete Active-Space Second-Order Perturbation Theory) quantum chemical method and Dunning’s cc-pVDZ basis sets. In both environments, our results suggest that the primary photophysical event is the population of the bright state. Afterwards, two likely deactivation pathways can take place, which is sustained by linear interpolation in internal coordinates defined via Z-Matrix scans connecting the most important characteristic points. The first one (Route 1) is the same relaxation mechanism observed for uracil, its canonical analogue, i.e., internal conversion to the ground state through an ethylenic-like conical intersection. The other route (Route 2) is the direct population transfer from the bright state to the triplet state via an intersystem crossing process involving the (/) singlet-triplet crossing point. As the spin-orbit coupling is not too large in either environment, we propose that most of the electronic population initially on the state returns to the ground following the same ultrafast deactivation mechanism observed in uracil (Route 1), while a smaller percentage goes to the triplet manifold. The presence of a minimum on the potential energy hypersurface in water can help to understand why experimentally it is noticed suppression of the triplet states population in polar protic solvent. 相似文献
992.
为了探索运用数码照片中光谱(红、绿、蓝)的像素计算得到的冠层覆盖度(canopy cover, CC)对玉米长势及氮素营养状态进行非破坏性监测的技术。通过获取玉米冠层的数码照片图像,定量化数码照片色彩参数与作物叶面积指数(leaf area index, LAI)、冠层干重(shoot dry matter weight, DM)、叶片氮素含量(leaf nitrogen content percentage, N%)之间的关系。试验于2012年和2013年在中国农业科学院试验田进行,运用基于Visual Basic Version 6.0研发的玉米冠层图像分析系统,分析了玉米品种中单909在3个氮素水平条件下分别于9叶展时期、抽雄期和灌浆期的CC、11种色彩指数与植株LAI,DM,N%及产量之间的相关性,并对相关性显著的指标进行了拟合与建模。结果表明,CC与LAI(r=0.93, p<0.01),DM(r=0.94, p<0.01),N%(r=0.82, p<0.01)之间均达到了极显著水平;用CC估算LAI,DM和N%的模型均为幂函数,方程式分别是y=3.281 2x0.763 9,y=283.658 1x0.553 6,y=3.064 5x0.932 9;用与建模相独立的数据对模型验证,结果表明,CC估算LAI模型的实测值与模拟值基于1∶1直线的R2,RMSE和RE分别是0.996,0.035和1.46%;CC估算DM模型的R2,RMSE和RE分别是0.978,5.408 g和2.43%;CC估算N%模型的R2,RMSE和RE分别是0.990,0.054和2.62%。综上所述,模型能够较准确的通过CC估算不同氮肥水平条件下玉米9叶展时期、抽雄期和灌浆期的LAI,DM与N%,表明应用数码相机的光谱信息可实现对玉米生长过程中的生长状况及氮素营养状态进行实时无损快速监测与预测。 相似文献
993.
Fedor Skuban Svetlana R. Lukić Dragoslav M. Petrović Imre O. Gúth 《Journal of Non》2009,355(37-42):2059-2062
The bulk chalcogenide glasses in the pseudo-binary system (As2Se3)100?x(SbSI)x (with x = 20, 30, 50, 70 and 80 at.%) were prepared from high-purity elemental components by melt-quenching technique. It is a system with the variable ratio of classical amorphous compound As2Se3 and the molecule of antimony-sulphoiodide, SbSI, which in the monocrystal form is characterized as a ferroelectric. The refractive-index behaviour (magnitude and spectral dispersion) of investigated glasses was determined by the prism method and analyzed. To calculate and discuss the parameters of dispersion in the band gap region three different approaches were used (Cauchy, Sellmeier and Wemple–DiDomenico single-oscillator model). The comparison of the results shows good agreement between all applied models. It was found that the value of the refractive-index shows normal dispersion behaviour and increases with the increase of Sb (or SbSI) content in the investigated system, whereas the optical gap of these glasses Eg slightly decreases. 相似文献
994.
M. L. G. Monteiro E. T. Mársico C. A. Lázaro C. A. Conte-Júnior 《Journal of Analytical Chemistry》2016,71(5):459-470
The chromatography techniques are partially characterized by presence of two phases (stationary and mobile), which allows identification, semi-quantification or quantification of important compounds in different matrices. Among chromatography methods, the thin-layer chromatography (TLC) must be considered for using in routine laboratories due to a number of advantages such as practicality, fast results and effectiveness, low cost, and simultaneous determination of analytes. This review describes the application of this technique to foods of animal origin, as well as compares TLC with other chromatographic methods. TLC has a strong potential as a surrogate chromatographic model for qualitative and quantitative analysis. Therefore, several modifications have been carried out to the conventional TLC system. Nevertheless, further studies should be performed in order to contribute with the scientific community and propagate the TLC method, which has performance and economic advantages compared to other chromatographic techniques. 相似文献
995.
Urzúa J. Carbajo J. Yáñez C. Marco J. F. Squella J. A. 《Journal of Solid State Electrochemistry》2016,20(4):1131-1137
Journal of Solid State Electrochemistry - We report that glassy carbon electrodes (GCE) modified with multi-walled carbon nanotubes (MWCNTs) can be derivatized with 2,7-dinitro-9-fluorenone... 相似文献
996.
Román?OrúsEmail author 《The European Physical Journal B - Condensed Matter and Complex Systems》2014,87(11):280
This is a short review on selected theory developments on tensor network (TN) states for strongly correlated systems. Specifically, we briefly review the effect of symmetries in TN states, fermionic TNs, the calculation of entanglement Hamiltonians from projected entangled pair states (PEPS), and the relation between the multi-scale entanglement renormalization ansatz (MERA) and the AdS/CFT or gauge/gravity duality. We stress the role played by entanglement in the emergence of several physical properties and objects through the TN language. Some recent results along these lines are also discussed. 相似文献
997.
Young-Joo Eo Wonha Lee Kyunhwan Kim SeJin Ahn Ara Cho Jihye Gwak Kyunghoon Yoon Se Youn Moon Hyo Rim Jung Jin Hyeok Kim Jae Ho Yun 《Current Applied Physics》2014,14(10):1349-1355
Carbon-free CuInSe2 (CIS) thin film with a dense microstructure has been prepared using a novel non-vacuum based fabrication route. CuxSy and In2Se3 binary nanoparticles, approximately 10 nm in size, were synthesized by a low temperature colloidal process. The precursor film was deposited using the coating ink formulated with the binary nanoparticles and pyridine, and then annealed in the rapid thermal annealing (RTA) chamber at 540 °C for 15 min under selenium (Se) atmosphere. Scanning electron micrographs, X-ray diffraction patterns and Raman spectra showed a phase pure carbon-free and dense CIS thin film was prepared in this method. A solar cell device fabricated using this CIS thin film showed the following photovoltaic characteristics: VOC = 350 mV, JSC = 24.72 mA cm−2, FF = 38.73% and η = 3.36% under standard AM 1.5 condition. 相似文献
998.
The problem of pattern formation by adsorbates undergoing attractive lateral interactions, is described by a parabolic integrodifferential equation having the scaled inverse temperature ? and the scaled pressure α of the vapor phase as parameters. A coexistence region of high- and low-coverage stable homogeneous states has been reported in the (?, α) plane. In the small interaction-range limit an effective diffusion coefficient can be defined, which becomes however negative for a coverage range in between the stable homogeneous ones. A novel free-energy-like Lyapunov functional is found here for this problem. When evaluated on the homogeneous states, it leads to a Maxwell-like construction which selects essentially the same value α(?) as the originally posited zero front-velocity condition. Moreover, its value on static fronts at this particular α(?) coincides with those of the homogeneous states. This article is dedicated to Prof. Helmut Brand with occasion of his 60th birthday. 相似文献
999.
N. Araújo M. Mendoza Jiménez F. Wittel 《The European physical journal. Special topics》2014,223(11):2063-2064
More than 30 years of scientific endeavor have brought us from programming simple models to impressive simulations of dynamic systems. Lattice models like Potts, percolation, fuse, fiber bundle, and growth models, just to name a few, are the prototypes or godfathers of statistical mechanics. With the availability of more powerful tools it became possible to develop these models and apply them on complex topologies, finding important practical applications in socio-technological systems (e.g., opinion dynamics, traffic, communication networks) and to engineering problems (e.g., fracture phenomena, mass transport). In parallel, particle models evolved from a hand full of interacting discs to three dimensional multibillion particle simulations that successfully describe interesting fracture phenomena, granular flow, and even fluid flow for engineering applications. Prof. Dr. Hans Jürgen Herrmann has dedicated his professional life to this journey. 相似文献
1000.
Raúl Machado 《Frontiers of Physics》2014,9(4):490-510
The influence of the use of the generalized Hermite polynomial on the Hermite-based lattice Bofiz- mann (LB) construction approach, lattice sets, the thermal weights, moments and the equilibrium distribution function (EDF) are addressed. A new moment system is proposed. The theoretical possibility to obtain a unique high-order Hermite-based singel relaxation time LB model capable to exactly inatch some first hydrodynamic inoments thermally i) on-Cartesian lattice, ii) with thermal weights in the EDF, iii) whilst the highest possible hydrodynamic moments that are exactly reatched are obtained with the shortest on-Cartesian lattiee sets with some fixed real-valued temperatures, is also analyzed. 相似文献