长株潭传统产业集群的核心竞争力

以产业价值链为主线,结合长沙-株洲-湘潭三市传统产业的竞争优势及其变化趋势思考,探讨了全球生产体系下的国际分工格局及其变化趋势,认为产业竞争力并不必然决定于产业层次,而更主要决定于创造附加价值的能力.最后,提出提升传统产业竞争优势的思路.     

Validation of a High-Performance Liquid Chromatography with Photodiode Array Detection Method for the Separation and Quantification of Antioxidant and Skin Anti-Aging Flavonoids from Nelumbo nucifera Gaertn. Stamen Extract

Nelumbo nucifera Gaertn., or the so-called sacred lotus, is a useful aquatic plant in the Nelumbonaceae family that has long been used to prepare teas, traditional medicines as well as foods. Many studies reported on the phytochemicals and biological activities of its leaves and seeds. However, to date, only few studies were conducted on its stamen, which is the most important ingredient for herbal medicines, teas and other phytopharmaceutical products. Thus, this present study focuses on the following: (1) the application of high-performance liquid chromatography with photodiode array detection for a validated separation and quantification of flavonoids from stamen; (2) the Nelumbo nucifera stamen’s in vitro and in cellulo antioxidant activities; as well as (3) its potential regarding the inhibition of skin aging enzymes for cosmetic applications. The optimal separation of the main flavonoids from the stamen ethanolic extract was effectively achieved using a core-shell column. The results indicated that stamen ethanolic extract has higher concentration of in vitro and in cellulo antioxidant flavonoids than other floral components. Stamen ethanolic extract showed the highest protective effect against reactive oxygen/nitrogen species formation, as confirmed by cellular antioxidant assay using a yeast model. The evaluation of potential skin anti-aging action showed that the stamen extract has higher potential to inhibit tyrosinase and collagenase compared with its whole flower. These current findings are the first report to suggest the possibility to employ N. nucifera stamen ethanolic extract as a tyrosinase and collagenase inhibitor in cosmetic applications, as well as the utility of the current separation method.     

Fabrication of solenoid-type microinductor with different magnetic core schemes by MEMS technique

0 IntroductionThere has been a great demand on micro DC/DCconverter for the applications of the portable electronicproducts such as mobile communication product CDMA(Code Division Multiple Access) ,portable notebookcom-puter ,microprocessor ,digital camcorder andso on.Mag-netic components such as inductors and transformers arethe essential components in constructingthe power supplytransformer ,filter , oscillator , amplifier and micro DC/DCconverter ,andthe miniaturization of inductor an…     

Preparation of Highly Stable and Photoluminescent Cadmium-Free InP/GaP/ZnS Core/Shell Quantum Dots and Application to Quantitative Immunoassay

Indium phosphide (InP) quantum dots (QDs) are ideal substitutes for widely used cadmium-based QDs and have great application prospects in biological fields due to their environmentally benign properties and human safety. However, the synthesis of InP core/shell QDs with biocompatibility, high quantum yield (QY), uniform particle size, and high stability is still a challenging subject. Herein, high quality (QY up to 72%) thick shell InP/GaP/ZnS core/shell QDs (12.8 ± 1.4 nm) are synthesized using multiple injections of shell precursor and extension of shell growth time, with GaP serving as the intermediate layer and 1-octanethiol acting as the new S source. The thick shell InP/GaP/ZnS core/shell QDs still keep high QY and photostability after transfer into water. InP/GaP/ZnS core/shell QDs as fluorescence labels to establish QD-based fluorescence-linked immunosorbent assay (QD-FLISA) for quantitative detection of C-reactive protein (CRP), and a calibration curve is established between fluorescence intensity and CRP concentrations (range: 1–800 ng mL⁻¹, correlation coefficient: R² = 0.9992). The limit of detection is 2.9 ng mL⁻¹, which increases twofold compared to previously reported cadmium-free QD-based immunoassays. Thus, InP/GaP/ZnS core/shell QDs as a great promise fluorescence labeling material, provide a new route for cadmium-free sensitive and specific immunoassays in biomedical fields.     

二氧化钚分子的多体展式势能函数

从导出基态PuO2分子的电子状态X5Σ g正确地判断其离解极限出发,采用MP2方法,应用相对论有效原子实模型(RECP)优化出PuO2(X5Σ g)分子稳定构型为线性OPuO(D∞h),其平衡核间距Re=0.18004nm.同时也计算出振动频率,并优化出存在亚稳态的Pu-O-O(C∞v)构型.使用多体项展式理论方法,导出了基态PuO2分子的分析势能函数.该势能表面准确地再现了O-Pu-O(D∞h)平衡结构和亚稳态的Pu-O-O(C∞v)构型.然后根据势能函数等值图讨论了O(3Pg) PuO反应的势能面静态特征.     

近5年化学奥林匹克(初赛)试题的分析及建议

从化学核心素养出发，分析近5年化学奥林匹克（初赛）试题考查的学生知识水平、能力水平、素养水平，并针对培养中学生核心素养的教学实践提出建议。     

基于化学核心素养培养的高中有机实验教学

调查发现,当前对高中有机实验教学普遍重视不够,教师缺乏通过有机实验教学培养学生学科核心素养的意识。提出以下建议：深度解读课程标准,增强实验教学意识;发挥实验教学功能,设计课题式探究实验教学;把握有机教学特点,巧设问题探究性实验;培训教师实验技能,加强实验操作能力。     

基于“真实情境与实际问题”的化学试题命制——以“碳九泄漏事故”为例

以“11·4福建泉港碳九泄漏事故”为测试载体,在深入挖掘和甄选考点后,结合当前《普通高中化学课程标准（2017年版）》对考试评价的有关说明和试题命制基本理论及技术要求,命制了一道高中化学考试试题,并在文中对试题的测试目标,如认知操作、核心素养和达到的学业质量水平加以详细分析,对试题命制的技术性要求辅以论证,以期能给同行以核心素养为测试宗旨的命题提供一些参考。     

化学学科核心素养在高中教材习题中的表现—以人教版教材为例

教材习题是落实新课标倡导的基于化学学科核心素养进行评价的重要载体。以化学学科核心素养的水平划分和学业质量水平为依据,分析人教版高中必修化学教材课后习题考查的核心素养及其水平。结果表明,2007年版和2019年版教材均注重全面考查核心素养和对基础性的考查,突出考查宏观辨识与微观探析素养,突出化学本质;但2019年版教材习题在数量上有所减少,加强了科学思维和科学实践的考查,合理拓展了核心素养考查的广度和深度。最后,依据习题特征获得相应的教学启示,以促进学生核心素养的发展。     

提升化学学科核心素养的高中化学教学——以“金属的防护”为例

针对人教版选修1《化学反应原理》第4章第3节“金属的腐蚀与防护”课时2“金属的防护”进行教学实践探索,融合STEM教育理念促进知识与社会生活结合。选用任务情境“家用电热水器碳钢内胆防腐”,通过实验探究构建起电化学防护的认知模型,再将模型应用于实际生产生活问题的解决,进行热水器内胆的防腐设计。在真实情境问题的解决中,将知识、方法、应用等3者融合,培养学生的问题意识和创新思维,逐步内化并表现出化学学科核心素养。