美国科学教育研究资助体系分析及其启示

加强科学教育是推进教育、科技、人才“三位一体”的统筹部署和实现科技创新自立自强的基础性工程。虽然科学教育已经在政策和实践层面备受关注,且已取得明显进展,我国科学教育依然面临着诸多的挑战与不足,其关键原因之一是支撑科学教育高质量发展的科学教育研究资助体系的缺乏。鉴于美国在科学教育研究领域的引领地位及其形成的完善的研究资助格局,本文全面介绍了美国科学教育研究资助体系的概况,深入分析了以美国国家科学基金会为代表的联邦政府机构对于科学教育的资助布局及其对K-12教育阶段的资助计划,形成了对于建立我国科学教育研究资助体系的建议。

基于大数据的城市规划决策支持系统研究

城市化发展速度迅猛提升,科技革新步伐不停,依靠大数据支持的城市规划决策辅助系统受到广泛关注。大数据技术的运用给城市规划抉择呈现了崭新观察角度与手段,通过搜集、整合和剖析众多城市信息,系统性地阐释城市成长模式与动向,赋予规划者科学的决策辅助。论文以大数据的定义和特征为起点,探讨了如何利用大数据分析来建立都市规划决策支持系统,包括数据的采集、处理和决策框架的构建等关键环节,目的是为城市规划决策提供全新的思路和方法,助力城市规划向科学化、智能化转型。

A Filtering Approach Based on MMAE for a SINS/CNS Integrated Navigation System

This paper explores multiple model adaptive estimation(MMAE) method, and with it, proposes a novel filtering algorithm. The proposed algorithm is an improved Kalman filter— multiple model adaptive estimation unscented Kalman filter(MMAE-UKF) rather than conventional Kalman filter methods,like the extended Kalman filter(EKF) and the unscented Kalman filter(UKF). UKF is used as a subfilter to obtain the system state estimate in the MMAE method. Single model filter has poor adaptability with uncertain or unknown system parameters,which the improved filtering method can overcome. Meanwhile,this algorithm is used for integrated navigation system of strapdown inertial navigation system(SINS) and celestial navigation system(CNS) by a ballistic missile's motion. The simulation results indicate that the proposed filtering algorithm has better navigation precision, can achieve optimal estimation of system state, and can be more flexible at the cost of increased computational burden.

Facile synthesis of colloidal nitrogen-doped titanium carbide sheets with enhanced electrochemical performance

Heteroatom nitrogen doping in two-dimensional transition metal carbides,known as MXenes,has been considered as a promising strategy for modulating their electronic structure and electrochemical reactivity.While hightemperature annealing in the presence of a nitrogen source has been one popular method to introduce nitrogen,annealing exfoliated multilayered MXenes typically brings about incomplete delamination and the treatment of delaminated monolayer MXenes often leads to irreversible restacking.Here,starting from the typical carbide precursor,we developed an aqueous colloid containing monolayered nitrogen-doped titanium carbide sheets with excellent dispersity and stability.This achievement is critically dependent on the retaining of the hydrophilic surface of host layers during annealing treatment.The successful realization of nitrogen doping into individual MXene monolayers resulted in enhanced electrical conductivity and redox reactivity,for which the sample exhibited excellent capacitive electrochemical performance(586 F/g at a scan rate of 5mV/s)and cycling stability(capacitance retention of 96.2%after 104 cycles at 5 A/g).This paper presents a feasible and simple strategy for designing nitrogen-doped MXenes colloid,the realization of which promises its facile uses in liquid phase engineering techniques toward versatile applications.

基于三位一体教学模式的学前教育专业教法课创新实践研究——以《学前儿童科学教育活动》课程为例

当今学前教育师资的培养越来越重视实践能力的培养和专业技能的提升,高校作为培养学前教育专业学生的主要机构,在课程组织实施方面进行了一系列改革,试图转变传统重理论学习轻实践练习的局面。在这种形势下,“理论讲解+案例分析+实践练习”结合的三位一体教学模式成为学前教育专业教法课程教学模式改革的一大趋势。科学教育作为五大领域教法课程的一部分,对学生科学素养,科学技能,科学活动的设计与组织的提高至关重要,是学生必备的专业技能。科学教育领域三位一体教学模式的实施在具体内容的学习中通过课堂中及课堂后的三位一体创新教学实践来实现。实践证明,三位一体教学模式在科学教育的学习中成效显著,可以广泛应用于其他教法课的组织。

Profiling the m^(6)A-regulated RNA expression patterns and alternative splicing features in esophageal carcinoma

The m^(6)A modification involves almost all aspects of RNA biology,including the alternative splicing of mRNA precursors,mRNA transport and stability,and miRNA processing and regulation of target genes.1,2 Alternative splicing controlling the information storage and RNA translation involves the regulation of various biological processes.3,4,5 Here,we integrated the genomic information of 161 esophageal cancer(EC)samples to comprehensively evaluate the m^(6)A modification patterns and correlated the m^(6)A modification pattern with the prognosis of EC patients,where two distinct m^(6)A modification patterns were proposed.The combined effects of high m^(6)Ascore and low TMB correlated with a better prognosis of EC patients.In addition,we found an inherent correlation between m^(6)A modification and the occurrence of alternative splicing events in EC patients.Altogether,we established a scoring system to quantify the m^(6)A modification pattern with RNA alternative splicing events in individual EC patients(Fig.S1).

Ultrasound-assisted co-precipitation synthesis of mesoporous Co_(3)O_(4)–CeO_(2)composite oxides for highly selective catalytic oxidation of cyclohexane

The one-step highly selective oxidation of cyclohexane into cyclohexanone and cyclohexanol as the essential intermediates of nylon-6 and nylon-66 is considerably challenging.Therefore,an efficient and low-cost catalyst must be urgently developed to improve the efficiency of this process.In this study,a Co_(3)O_(4)–CeO2 composite oxide catalyst was successfully prepared through ultrasound-assisted co-precipitation.This catalyst exhibited a higher selectivity to KA-oil,which was benefited from the synergistic effects between Co^(3+))/Co^(2+))and Ce^(4+)/Ce^(3+)redox pairs,than bulk CeO2 and/or Co_(3)O_(4).Under the optimum reaction conditions,89.6%selectivity to KA-oil with a cyclohexane conversion of 5.8%was achieved over Co_(3)O_(4)–CeO2.Its catalytic performance remained unchanged after five runs.Using the synergistic effects between the redox pairs of different transition metals,this study provides a feasible strategy to design high-performance catalysts for the selective oxidation of alkanes.

Fruit size control by a zinc finger protein regulating pericarp cell size in tomato

Fruit size is largely defined by the number and size of cells in the fruit.Endoreduplication–a specialized cell cycle–is highly associated with cell expansion during tomato fruit growth.However,how endoreduplication coupled with cell size is regulated remains poorly understood.In this study,we identified a zinc finger gene SlPZF1(Solanum lycopersicum PERICARP-ASSOCIATED ZINC FINGER PROTEIN 1)that was highly expressed in the pericarp of developing fruits.Plants with altered SlPZF1 expression produced smaller fruits due to the reduction in cell size associated with weakened endoreduplication.Overexpressing SlPZF1 delayed cell division phase by enhancing early expression of several key cell cycle regulators including SlCYCD3;1 and two plant specific mitotic cyclin-dependent protein kinase(SlCDKB1 and SlCDKB2)in the pericarp tissue.Furthermore,we identified 14 putative SlPZF1 interacting proteins(PZFIs)via yeast two hybrid screening.Several PZFIs,including Pre-mRNA-splicing factor(SlSMP1/PZFI4),PAPA-1-like conserved region family protein(PZFI6),Fanconi anemia complex components(PZFI3 and PZFI10)and bHLH transcription factor LONESOME HIGHWAY(SILHW/PZFI14),are putatively involved in cell cycle regulation.Our results demonstrate that fruit growth in tomato requires balanced expression of the novel cell size regulator SlPZF1.

Mesoporous silicon sulfonic acid as a highly efficient and stable catalyst for the selective hydroamination of cyclohexene with cyclohexylamine to dicyclohexylamine in the vapor phase

In this work,a new mesoporous silicon sulfonic acid catalyst derived from silicic acid has been successfully prepared by the chemical bonding method.The physicochemical properties of mesoporous silicon sulfonic acid catalysts have been systematically characterized using various techniques.The results demonstrate that sulfonic acid groups have been grafted on silicic acid by forming a new chemical bond(Si-O-S).The mesoporous silicon sulfonic acid exhibits excellent catalytic performance and stability in the vapor phase hydroamination reaction of cyclohexene with cyclohexylamine.Cyclohexene conversion of 61% and 97% selectivity to dicyclohexylamine was maintained after running the reaction for over 350 h at 280℃.The developed mesoporous silicon sulfonic acid catalyst shows advantages of low cost,superior acid site accessibility,and long term reactivity stability.Moreover,a possible catalytic hydroamination reaction mechanism over silicon sulfonic acid was suggested.It has been demonstrated that the sulfonic acid groups of the catalyst play an important role in the hydroamination.The present work provides a simple,efficient,and environmentally friendly method for the hydroamination of cyclohexene to valuable dicyclohexylamine,which also shows important industrial application prospects.

One-step synthesis of c-caprolactam via the liquid phase catalytic nitrosation of cyclohexane in the presence of concentrated sulfuric acid

A simple and efficient approach for the synthesis of e-caprolactam via the liquid phase nitrosation of cyclohexane and nitrosyl sulfuric acid in the presence of concentrated sulfuric acid has been developed. A series of novel A1VPO composites were prepared by an impregnation method and the composites were then employed to catalyze the nitrosation reaction of cyclohexane and nitrosyl sulfuric acid. Compared to the reaction using fuming sulfuric acid, the selectivity for the desired product was significantly improved using this one-step catalytic process. This method affords a shortcut to prepare ecaprolactam and its analogs from cyclohexane.