Lu-Eu共掺杂Ga2O3的光电性质的第一性原理计算

宽禁带半导体β-Ga₂O₃因为具有优良的物理化学性能而成为研究热点.本文基于DFT(Density Functional Theory)的第一性原理方法,先采用PBE(Perdew-Burke-Ernzerhof)中的GGA(Generalized Gradient Approximation)和GGA+U(Generalized Gradient Approximation-Hubbard U)的方法计算了本征β-Ga₂O₃,Lu掺杂浓度为12.5%的β-Ga₂O₃及Lu-Eu共掺杂浓度为25%的β-Ga₂O₃结构的晶格常数、能带结构和体系总能量.发现采用GGA+U的方法计算的带隙值更接近实验值,于是采用GGA+U的方法计算了本征β-Ga₂O₃,Lu掺杂的β-Ga₂O₃以及Lu-Eu共掺杂的β-Ga₂O...     

一种基于萘酰亚胺的检测细胞内pH值的荧光探针及其生物成像应用

细胞内溶酶体的pH值对细胞自噬、吞噬、酶加工等各项生命活动有着重要影响.细胞核是真核细胞中最大的细胞器,控制着生物体内的遗传和代谢过程,参与代谢过程的酶对pH值的变化很敏感.因此,研究细胞体内的pH值变化至关重要.我们设计并以简单的两步反应合成了一种新型荧光探针NpH-1.该探针以萘酰亚胺作为荧光团,以吗啉基团作为对p...     

Optimization of Ultrasound-Assisted Cellulase Extraction from Nymphaea hybrid Flower and Biological Activities: Antioxidant Activity,Protective Effect against ROS Oxidative Damage in HaCaT Cells and Inhibition of Melanin Production in B16 Cells

In this study, ultrasonic-assisted cellulase extraction (UCE) was applied to extract flavonoids and polyphenols from the Nymphaea hybrid flower. The extraction conditions were optimized using the response surface method (RSM) coupled with a Box-Behnken design. The crude extract of Nymphaea hybrid (NHE) was further purified using AB-8 macroporous resins, and the purified extract (NHEP) was characterized by FTIR and HPLC. In vitro activity determination by chemical method showed that NHEP displayed strong free radical scavenging abilities against the DPPH and ABTS radicals, good reduction power, and hyaluronidase inhibition. The cell viability by CCK-8 assays showed that NHEP had no significant cytotoxicity for B16 and HaCaT cells when the concentration was below 100 μg/mL and 120 μg/mL, respectively. NHEP with a concentration of 20–160 μg/mL can more effectively reduce the ROS level in H₂O₂ damaged HaCaT cells compared with 10 μg/mL of VC. The 40 μg/mL of NHEP had similar activity against intracellular melanin production in the B16 melanoma cells compared with 20 μg/mL Kojic acid. Good activities of antioxidation, whitening and protective effect against H₂O₂-induced oxidative damage promote the potential for NHEP as a functional raw material in the field of cosmetics and medicine.     

Investigating thermal dimerization of N-methyl-flindersine. Syntheses and characterizations of paraensidimerines

Thermal dimerization of N-methyl-flindersine is reported here. This work commenced with the intent to access new Diels-Alder-type dimeric bis-pyranylquinoline alkaloids melicodenines but uncovered and characterized naturally occurring paraensidimerine F, F′and C′, as well as two new bis-quinolone derivatives.     

Characterizing regions of attraction for piecewise affine systems by continuity of discrete transition functions

Nonlinear Dynamics - Based on an analysis of the continuity of discrete transition functions, this paper presents a new approach for characterizing piecewise affine (PWA) systems’ regions of...     

Regioselective TfOH-mediated hydroamidation of ynamides with nitriles

A new TfOH-mediated reaction of ynamides with nitriles as nucleophiles has been developed. The reaction works efficiently under mild reaction conditions to afford a new class of α-acylaminoenamides readily via the intermediacy of keteniminium ion. The reaction displays generality and a broad substrates scope. Additionally, the α-acylaminoenamides could be transformed to highly substituted pyridine, 4-aminopyrimidine or isoquinoline cores.     

Synthesis of Rod-Like Co3O4 Catalyst Derived from Co-MOFs with Rich Active Sites for Catalytic Combustion of Toluene

Catalysis Surveys from Asia - Co3O4 catalyst derived from Co-MOFs demonstrated rich active sites in the catalytic reaction. In this paper, we prepared the rod-like Co3O4 catalysts by calcining...     

Synthesis and mesomorphic properties of four-ring liquid crystals containing 2,3-difluorophenyl and 1,3-dioxane units

Two series of novel liquid crystalline materials were synthesized: 2-(2,3-difluoro-4-alkoxyphenyl)-5-[4-(4-alkylcyclohexyl)phenyl]-1,3-dioxanes (A _m-n and 2-(2,3-difluoro-4-alkylphenyl)-5-[4-(4-alkylcyclohexyl)phenyl]-1,3-dioxanes (B _m-n ). Their mesmorphic properties were characterized by polarizing optical microscopy and differential scanning calorimetry. All these compounds exhibit broad mesomorphic phases, and most of them show wide smectic C phases and the phase sequence Cr-SmC-SmA-N-I. The relationship between properties and chemical structures is discussed in detail.