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数学底层思维即用数学的眼光观察世界、用数学的思维分析世界以及用数学的语言表达世界,是人们面对自然和社会中纷繁多样的现象和问题时,所展现的自发的、不依赖监督的、融汇数学学科核心素养的思维方式.作为国家高中新课程标准中数学六大核心素养之一的数学建模,是培养学生数学底层思维的良好载体,对人才培养和社会发展均起到良好的促进作用.本文主要阐述了数学建模对高中生构建数学底层思维的作用,并结合教学实例给出教学实施建议. 相似文献
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JPC – Journal of Planar Chromatography – Modern TLC - High-performance thin-layer chromatography, which is a quick qualitative and quantitative method, was used to determine 3 kinds of... 相似文献
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Ping Lv Xin Shen Zhiliyu Cui Bo Li Qiangqiang Xu Zhuo Yu Weijie Lu Haonan Shao Yan Ge Zhenhui Qi 《Journal of polymer science. Part A, Polymer chemistry》2021,59(23):3001-3008
Fiber-reinforced-concrete (FRC) mechanism refers short discrete fibers that are uniformly distributed and randomly oriented, which offers an effective way to improve the mechanical performance of concrete. In the design of supramolecular polymers, an analogous concept of FRC appears to have been considered very rarely-although fibrous structure has been frequently observed/generated during the supramolecular polymerization. In this work, we apply the alkane thermosets, octadecane (C18H38) and tetracosane (C24H50), taking the role of “concrete”, and the low-molecular-weight monomer with long alkyl chains as the essential “fiber” component, to fabricate the “fiber reinforced supramolecular polymer”. Very much like FRC mechanism in material science, the resulting fiber reinforced supramolecular polymer thus exhibit unusually high mechanical strength and stiffness, which is unprecedented in the conventional supramolecular strategy. 相似文献
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Long Cheng Haonan Yang Xingyu Chen Guozhen Liu Dr. Yanan Guo Prof. Gongping Liu Prof. Wanqin Jin 《化学:亚洲杂志》2021,16(20):3162-3169
Graphene oxide (GO) is a promising two-dimensional building block for fabricating high-performance gas separation membranes. Whereas the tortuous transport pathway may increase the transport distance and lead to a low gas permeation rate, introducing spacers into GO laminates is an effective strategy to enlarge the interlayer channel for enhanced gas permeance. Herein, we propose to intercalate CO2-philic MIL-101(Cr) metal-organic framework nanocrystals into the GO laminates to construct a 2D/3D hybrid structure for gas separation. The interlayer channels were partially opened up to accelerate gas permeation. Meanwhile, the intrinsic pores of MIL-101 provided additional transport pathways, and the affinity of MIL-101 to CO2 molecules resulted in higher H2/CO2 diffusion selectivity, leading to a simultaneous enhancement in gas permeance and separation selectivity. The MIL-101(Cr)/GO membrane with optimal structures exhibited outstanding and stable mixed-gas separation performance with H2 permeance of 67.5 GPU and H2/CO2 selectivity of 30.3 during the 120-h continuous test, demonstrating its potential in H2 purification application. 相似文献
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Yuan Jiang Haibao Shao Hangning Xu Jiahao Yang Yi Wang Haonan Xiong Pengyao Wang Xilin Wang 《Materials Today Chemistry》2021
The traditional aqueous route to synthesis CdTe/CdS Core/shell (c/s) quantum dots (QDs) via decomposition of Cd-thiol complexes is usually time consuming. Herein, an ultrafast and facile aqueous synthetic approach under atmospheric pressure for CdTe/CdS c/s QDs with emission from the green to the near-infrared window (535–820 nm) is reported. With purified CdTe core QDs diluted in solution of Cd-3-mercaptopropionic acid (MPA) complexes, CdTe/CdS c/s QDs with emission wavelengths at 700 and 800 nm can be obtained within 20- and 45-min refluxing under the optimized experimental conditions, respectively. This is the most rapid way to prepare CdTe/CdS c/s QDs in aqueous phase, and the obtained QDs were highly luminescent without postsynthesis treatment. The influences of various experimental factors, including Cd2+ concentration, MPA-to-Cd ratio, pH value, and dilution ratio on the growth rate and luminescent properties of the obtained CdTe/CdS c/s QDs, have been taken into consideration. The three processes “purification-dilution-addition” ensure the synthesis environment with high pH value and low core concentration and have a marked impact on the rapid synthesis rate and the resulting high fluorescence of CdTe/CdS c/s QDs. 相似文献
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Re‐Appearance of Cooperativity in Ultra‐Small Spin‐Crossover [Fe(pz){Ni(CN)4}] Nanoparticles 下载免费PDF全文
Haonan Peng Dr. Simon Tricard Gautier Félix Dr. Gábor Molnár Dr. William Nicolazzi Dr. Lionel Salmon Dr. Azzedine Bousseksou 《Angewandte Chemie (International ed. in English)》2014,53(41):10894-10898
A reverse nanoemulsion technique was used for the elaboration of [Fe(pz){Ni(CN)4}] nanoparticles. Low‐temperature micellar exchange made it possible to elaborate ultra‐small nanoparticles with sizes down to 2 nm. When decreasing the size of the particles from 110 to 12 nm the spin transition shifts to lower temperatures, becomes gradual, and the hysteresis shrinks. On the other hand, a re‐opening of the hysteresis was observed for smaller (2 nm) particles. A detailed 57Fe Mössbauer spectroscopy analysis was used to correlate this unusual phenomenon to the modification of the stiffness of the nanoparticles thanks to the determination of their Debye temperature. 相似文献
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Yue Zhang Wenhao Liu Jin Si Xiyu Zhu Chengping He Haonan Zhao Hai-Hu Wen 《中国科学:物理学 力学 天文学(英文版)》2018,(9)
Superconductivity is observed in a new nontoxic cuprate system Ga-Ba-Ca-Cu-O,with T_c=82 K for Ga Ba_2Ca_5Cu_6O_(14+δ)(Ga-1256)and T_c=116 K probably for Ga Ba_2Ca_3Cu_4O_(10+δ)(Ga-1234)or Ga Ba_2Ca_2Cu_3O_(8+δ)(Ga-1223),respectively.All compounds are fabricated by solid state reaction method under high pressure and high temperature.Samples are characterized by resistivity,magnetization and X-ray diffraction(XRD)measurements.The temperature dependence of magnetization measured in both zero-field-cooled and field-cooled processes on one sample(S1)shows two superconducting transitions at about 82 K and113 K.The estimated shielding fraction for the phase with T_cof 82 K is about 67%,while the fraction for another phase with T_(c )of 113 K is quite small.The XRD Rietveld refinement for S1 indicates two main phases existing in the sample,Ga-1256 with fraction of about 58%and non-superconducting Ca_(0.85)Cu O_2with fraction of about 42%respectively.Thus,we can conclude the superconducting phase with transition temperature of 82 K is due to Ga-1256.The resistivity measurement also confirms the superconductivity for S1,and the resistivity reaches zero at about 82 K.The temperature dependence of magnetization for another sample(S2)shows much higher superconducting shielding fraction for the phase with T_cof 116 K,which may be a promising prospective for the synthesis of Ga-1234 or Ga-1223 phase. 相似文献
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Frontispiece: Re‐Appearance of Cooperativity in Ultra‐Small Spin‐Crossover [Fe(pz){Ni(CN)4}] Nanoparticles 下载免费PDF全文