A reasonable prediction of photofission observables plays a paramount role in understanding the photofission process and guiding various photofission-induced applications, such as short-lived isotope production, nuclear waste disposal, and nuclear safeguards. However, the available experimental data for photofission observables are limited, and the existing models and programs have mainly been developed for neutron-induced fission processes. In this study, a general framework is proposed for characterizing the photofission observables of actinides, including the mass yield distributions (MYD) and isobaric charge distributions (ICD) of fission fragments and the multiplicity and energy distributions of prompt neutrons (np) and prompt γ rays (γp). The framework encompasses various systematic neutron models and empirical models considering the Bohr hypothesis and does not rely on the experimental data as input. These models are then validated individually against experimental data at an average excitation energy below 30 MeV, which shows the reliability and robustness of the general framework. Finally, we employ this framework to predict the characteristics of photofission fragments and the emissions of prompt particles for typical actinides including 232Th, 235, 238U and 240Pu. It is found that the 238U(γ, f) reaction is more suitable for producing neutron-rich nuclei compared to the 232Th(γ, f) reaction. In addition, the average multiplicity number of both npand γp increases with the average excitation energy. 相似文献
The determination of nonlinearities near the band edge of organic and polymeric electro-optic(EO)materials is important from the viewpoint of molecular nonlinear optics(NLO)and photonic device applications.Based on transmission-mode Stark effect electromodulation(EM)spectroscopy,we study the electric-field-induced changes in optical absorption and refraction of newly developed EO polymers from the visible to near-infrared(NIR)wavelengths and report record-high near-band-edge complex EO effects from poled thin films.Values ofΔn andΔk up to 10-3 and 10-2 are found at an applied electric field of 2.0×105-3.0×105V/cm.The study of linear optical properties of poled films by spectroscopic ellipsometry shows large polinginduced birefringence and a nearly two-fold increase in the extinction coefficients at the extraordinary polarization.Through the Kramers-Kronig analysis,we obtained the real and imaginary second-order nonlinear coefficients up to~3,500 and~5,600 pm/V,respectively,which are believed to be the highest NLO coefficients of poled polymers through the resonance enhancement.Our approach goes beyond the previous works,applicable only to several discrete wavelengths,to a full-spectral analysis with independent verification of slab waveguide measurements.By considering both the electroabsorption and electrorefraction effects,our study overcomes the limitation of the classic qualitative two-level model and provides a quantitative understanding of near-resonance optical nonlinearities of organic EO materials.It can inspire the exploration of high-speed,absorptive,or phase-shifting light-modulators using EO polymers for on-chip applications. 相似文献
Natural enzymes have been praised highly as ideal catalysts, presumably owing to their remarkable advantages of high efficiency, high selectivity, and mild reaction conditions. The reports of chemical simulation and systematic synthesis of natural enzymes such as peroxidase (POD) are rare because of their complex biological structures. POD represents a large family of oxidoreductases and offers a wide range of applications in many fields of science. Recent advance in the fusion of nanomaterial, catalysis, and biochemistry has inspired the development of artificial enzymes implemented with desired catalytic features of natural enzymes. Herein, we review the redox chemistry of POD and compare its catalytic performance to graphene-based nanomaterials (G-NMs) as POD mimetic nanoenzymes bases on catalytic center, binding site, and carrier function. Based on the viewpoints of stereo chemistry and molecular kinetic and dynamics in heterogeneous system, we evaluate and compare the suitability of different NMs as artificial enzyme constituent. We propose that reevaluates design strategies of graphene-based peroxidase (G-POD) mimetic materials and emphasizes on their selectivity (role as catalytic center, binding site, or carrier) is of uttermost. 相似文献
A highly selective and efficient LC–MS/MS method was developed to determine the plasma concentration of magnolol, hesperidin, neohesperidin and geniposide following oral administration of Zhi‐Zi‐Hou‐Po decoction in normal and depressed rats. Plasma samples were pretreated by protein precipitation with methanol. Chromatographic separation was performed on an XTerra® MS C18 column using a gradient elution with a mobile phase composed of acetonitrile–0.1% aqueous formic acid. The proposed method was validated to be specific, accurate and precise for the analytes determination in plasma samples. The calibration curves displayed good linearity over definite concentration ranges for the analytes. The intra‐ and inter‐day precision of the proposed method at three different levels were all within <11.13% and the relative errors ranged from ?8.46 to 8.93%. The recovery of the four compounds ranged from 82.72 to 89.08% and no apparent matrix effect was observed during sample analysis. After full validation, the established method was successfully applied for comparing the pharmacokinetics of four components between normal and depressed rats. The results showed that the AUC and Cmax of four analytes in depressed rats were significantly different from those in normal rats and might provide helpful information to guide the clinical use of Zhi‐Zi‐Hou‐Po to treat depression. 相似文献
Two Ag(I)-based coordination polymers, namely [Ag2(3,3′-tmbpt)(o-Hbdc)2]·H2O (1) and [Ag8(3,3′-tmbpt)4(1,2,4-Hbtc)4(H2O)] (2) (3,3′-tmbpt?=?1-((1H-1,2,4-triazol-1-yl)methyl)-3,5-bis(3-pyridyl)-1,2,4-triazole, o-H2bdc?=?1,2-benzenedicarboxylic acid and 1,2,4-H3btc?=?1,2,4-benzenetricarboxylic acid), have been synthesized. Single-crystal X-ray diffraction analyses, elemental analyses, infrared spectra, powder X-ray diffraction analyses and thermogravimetric analyses have been carried out to characterize the structures of 1 and 2. Compound 1 shows a (3,4)-connected 2D layered structure with a Schläfli symbol of (42·6)(42·63·8). The intermolecular O–H···O hydrogen-bonding interactions extend the 2D layer into a 3D supramolecular architecture. Compound 2 exhibits a (3,3)-connected double-layered structure with a Schläfli symbol of (4·8·10)2(82·10)2. The intermolecular C–H···O hydrogen-bonding interactions link the double-layers to form a 3D supramolecular architecture. Moreover, there are intramolecular and intermolecular π–π interactions in 1 and 2, which stabilize the whole 3D supramolecular architectures. The band gaps of 1 and 2 are 3.19 and 3.09 eV, respectively, indicating the potential of 1 and 2 as semiconductive materials with wide band gaps. Moreover, 1 and 2 emit intense blue-green light, which may be potential photoactive materials.
Graphic Abstract
Two Ag(I)-based 3D supramolecular coordination polymers constructed from a multidentate N-donor ligand and two aromatic polycarboxylate anions via hydrogen-bonding and π–π interactions have been synthesized and characterized. The band gaps and photoluminescent properties of the compounds have been studied.
International Journal of Theoretical Physics - A new quantum watermark algorithm is presented by combining maximum pixel difference partitioning with the least significant bit substitution... 相似文献
In recent years, the fingerprint of high‐performance liquid chromatography has been extensively applied in the identification and quality control of traditional Chinese medicine. It can be a potential protocol for assessing the authenticity, stability and consistency of traditional Chinese medicine and guaranteeing the expected biological activity. In this paper, a method using high‐performance liquid chromatography to identify and control the quality of the extract of Taraxacum mongolicum Hand.‐Mazz. (TME) was established. With this method, the correlation coefficients of the similarity of 10 batches were ≥0.994. The TME displayed a steady proliferative effect in Lactobacillus plantarum. In brief, this study successfully built a reliable, simple and efficient method to control and confirm the quality and the stability of biological activity of the TME. 相似文献