High-performance thin-layer chromatographic analysis of three components in Arnebia guttata Bunge

JPC – Journal of Planar Chromatography – Modern TLC - High-performance thin-layer chromatography (HPTLC) was used for the qualitative and quantitative analysis of...     

The Chemical Compositions,and Antibacterial and Antioxidant Activities of Four Types of Citrus Essential Oils

Nanfeng mandarins (Citrus reticulata Blanco cv. Kinokuni), Xunwu mandarins (Citrus reticulata Blanco), Yangshuo kumquats (Citrus japonica Thunb) and physiologically dropped navel oranges (Citrus sinensis Osbeck cv. Newhall) were used as materials to extract peel essential oils (EOs) via hydrodistillation. The chemical composition, and antibacterial and antioxidant activities of the EOs were investigated. GC-MS analysis showed that monoterpene hydrocarbons were the major components and limonene was the predominate compound for all citrus EOs. The antibacterial testing of EOs against five different bacteria (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium) was carried out using the filter paper method and the broth microdilution method. Kumquat EO had the best inhibitory effect on B. subtilis, E. coli and S. typhimurium with MIC (minimum inhibitory concentration) values of 1.56, 1.56 and 6.25 µL/mL, respectively. All citrus EOs showed the antioxidant activity of scavenging DPPH and ABTS free radicals in a dose-dependent manner. Nanfeng mandarin EO presented the best antioxidant activity, with IC₅₀ values of 15.20 mg/mL for the DPPH assay and 0.80 mg/mL for the ABTS assay. The results also showed that the antibacterial activities of EOs might not be related to their antioxidant activities.     

Persistence of Lower Dimensional Tori for a Class of Nearly Integrable Reversible Systems

In this paper we consider the persistence of lower dimensional invariant tori for a class of reversible systems, and prove that if the average of the linear terms has full rank, then the invariant torus with Diophantine frequencies persists under small perturbations.     

Degenerate lower dimensional tori in reversible systems

In this paper we prove the persistence of lower dimensional invariant tori with prescribed frequencies and singular normal matrices in reversible systems. The normal variable is two-dimensional and the unperturbed nonlinear terms in the differential equation for this variable have a special structure.     

OEA-1电视自准直仪的研制及应用

目前在光学车间普遍使用的光学比较测角仪视场大，测量精度低，而常用的测微自准直仪则测量精度高、视场小。这两种仪器均是通过目镜瞄准、读数，长时间工作，操作者容易疲劳。ＯＥＡ－１电视自准直仪是在比较测角仪和测微自准直仪的基础上，采用ＣＣＤ光电转换和视频信号技术研制成功的新一代自准直仪。它不仅视场大，而且测量精度高。同时，还能够根据对被测对象的要求在电视屏幕上任意地设定和显示公差带，实现对被测对象快速、准确的检测或判断。由于采用电视显示代替目镜观察，极大地减轻了操作者的劳动强度，提高了工作效率。     

强激光武器系统光学总体考虑

本文从强激光武器系统的构成出发，探讨包括强弱激光的各种光束输和控制原理，分析影响入射目标上辐射率的各种因素，描述各种分支光学系统的性能，最后就材料选择，耐强光的膜怪镀制自动聚焦等关键性技术问题作了介绍，并列表给出武器系统中各个光学组件的斯持列尔比和光效率的初步要求。     

On the reducibility of a class of nonlinear quasi-periodic system with small perturbation parameter near zero equilibrium point

This work focuses on the reducibility of the following real nonlinear analytical quasiperiodic system:

where A is a real 2×2 constant matrix, and f(t,0,)=O() and ∂_xf(t,0,)=O() as →0. With some non-resonant conditions of the frequencies with the eigenvalues of A and without any nondegeneracy condition with respect to , by an affine analytic quasiperiodic transformation we change the system to a suitable norm form at the zero equilibrium for most of the sufficiently small perturbation parameter .     

0.35 μm分步重复投影光刻物镜设计

介绍０．３５μｍ分步重复投影光刻物镜的设计要点，包括数值孔径、结构形式的确定、材料的选择。介绍了光刻物镜设计的难点、创新点及设计结果。     

Perylene diimide‐modified magnetic γ‐Fe2O3/CeO2 nanoparticles as peroxidase mimics for highly sensitive colorimetric detection of Vitamin C

Perylene diimide‐modified magnetic γ‐Fe₂O₃/CeO₂ nanoparticles (γ‐Fe₂O₃/CeO₂‐PDI) were prepared and exhibited excellent peroxidase‐like activity. The samples were characterized by HR‐TEM, XRD, Raman, N₂ adsorption, magnetic strength and XPS. The obtained γ‐Fe₂O₃/CeO₂‐PDI had size of 10~20 nm with high specific surface area of 77 m²/g, and could be easily separated from the aqueous solution by using a magnet, which are in favor of its practical application. Due to the decoration of PDI, the γ‐Fe₂O₃/CeO₂‐PDI possessed more surface defects (Ce³⁺) and active oxygen species than that of γ‐Fe₂O₃/CeO₂, resulting in the outstanding catalytic performance. And the composite catalyst also showed highly sensitive and selectivity toward VC with a limit of detection of 0.45 μM. Based on the fluorescent results, a possible hydroxyl radical (?OH) catalytic mechanism was proposed. It is believed that the as‐prepared γ‐Fe₂O₃/CeO₂‐PDI nanoparticles are promising biosensors applied for biomedical and food analysis.