Cultural Studies of Science Education
·
2021
·Vol. 16
·期 1
·47-69
·
IF 1.167
Rivera Seema,Oliveira Alandeom
The present study examines the pedagogical use of reading aloud of science trade books as an effective tool for teaching nature of science (NOS) to elementary students. To this end, we explore elementary teachers’ and students’ dialogic negotiation of NOS during interactive science read-alouds, as well as potential interactions between their sense-making patterns, NOS views, and trade-book representations of NOS. It was found that, when a book had explicit NOS aspects in it, a teacher with more informed NOS views was able to facilitate a more extended, open-ended, and inclusive discussion about NOS. Conversely, when the trade book had very explicit connections, a teacher with naïve NOS views was able to only superficially address these NOS aspects without going beyond or elaborating on the information available in the book. Furthermore, the latter discussion was characteristically close-ended, exclusive of students, and limited in sense-making. These findings underscore the need for further investigation of how particular NOS aspects are narrativized in science trade-books, and how elementary teachers can effectively guide students while facilitating explicit negotiation of particular types of trade book representations of NOS during interactive science read-alouds. It is argued that improving elementary science instruction requires a more sophisticated, theory-based understanding of how NOS instruction is mediated by stories and storytelling.
研究领域:
科学教育
·
小学教育
✓ 已验证
DOI
高影响因子
CARBON
·
2018
·
IF 7.082
Hetao Chu,Qianshan Xia,Zhichun Zhang,Yanju Liu,Jinsong Leng
Aircrafts are increasingly fabricated by carbon fiber reinforced polymer (CFRP) composites, because of the excellent specific stiffness and strength . However, lower electrical conductivity , leads to the drawback of the aircraft to lightning strike protection (LSP) changing from conductive metals to insulate composites. Herein, a sesame-cookie topography silver nanoparticle modified carbon nanotube paper (SMCNP) protective layer was developed to enhance LSP efficiency on the CFRP . The integrated material, SMCNP, could be molded directly on the surface layout of CFRP without any insulating adhesives. By contrast, carbon nanotube paper (CNP) and SMCNP were systematically studied on the influence of LSP and the possible protection mechanisms were discussed. Sesame-cookie silver nanoparticle not only enhances the electric conductivity, from 323 S/cm to 3600 S/cm in 14.14 wt%, but also provides a melted silver skeleton for extending current conduction along protection layer illustrated from the XPS and Raman analysis. SMCNP-CFRP maintains 92.1% residual mechanical property after simulated LS interaction which is much higher than that unprotected CFRP of 65.9%.
研究领域:
材料科学
·
航空工程
✓ 已验证
产品关联
DOI
高影响因子
Chemosensors
·
2023
·Vol. 11
·期 10
·531
·
IF 4.2
Mingzhu Wu,Jianhang Lin,Da Zheng,Yirui Yang,Zhihao Li,Zhengdong Zhu,Yonghui Shen,Gang Ni,Maofeng Zhang
Micro/nanoplastics are widespread in the environment and may cause severe damage to creatures and human beings. Micro/nanoplastic pollution has become a global focus issue; hence, the rapid and accurate detection of micro/nanoplastics is an essential step to ensure health. Herein, we report a surface-enhanced Raman scattering (SERS) technique to sensitively and quantitatively identify micro/nanoplastics in environmental water samples. A three-dimensional hierarchical Au@Ag nanostar (NSs) was synthesized and employed as an efficient SERS substrate. The “lightning rod effect” generated by tip branches of the nanostars and the coupling effect of the neighboring branches of the nanostar array enabled the ultra-trace detection of crystal violet (CV) down to 10−9M, even with a portable Raman device. Moreover, the hydrophobic property of the SERS substrate endowed it with a desirable enrichment effect, which meant an increase in the concentration or quantity of the micro/nanoplastic particles. And thereafter, the SERS sensor achieved a highly sensitive detection of polystyrene (PS) particle standard solution at a low concentration of 25 μg/mL or 2.5 μg/mL. Importantly, the detected concentration and the SERS intensity followed a nearly linear relationship, indicating the capability of quantitative analysis of micro/nanoplastics. In addition, the SERS sensor was successfully extended to detect PS particles in environmental water samples, including tap water, sea water, and soil water, and the detection concentration was determined to be 25 μg/mL, 2.5 μg/mL, and 25 μg/mL, respectively. The present Au@AgNSs array substrate with a two-order magnitude signal amplification further exhibited significant advantages in the label-free analysis of micro/nanoplastics in real water samples.Keywords:surface-enhanced Raman spectroscopy (SERS);Au@Ag nanostar;lightning rod effect;micro/nanoplastics;quantitative detection
研究领域:
环境科学
·
纳米技术
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
FOOD CHEMISTRY
·
2024
·
IF 8.5
Yu-ning Liu,Jian-jun Li,Guo-jun Weng,Jian Zhu,Jun-wu Zhao
Morphology regulation of heterodimer nanoparticles and the use of their asymmetric features for further practical applications are crucial because of the rich optical properties and various combinations of heterodimers. This work used silicon to asymmetrically wrap half of a gold sphere and grew gold branches on the bare gold surface to form heterogeneous nano pineapples (NPPs) which can effectively improve Surface-enhanced Raman scattering (SERS) properties through chemical enhancement and lightning-rod effect respectively. The asymmetric structures of NPPs enabled them to self-assemble into the monolayer membrane with consistent branch orientation. The prepared substrate had high homogeneity and better SERS ability than disorganized substrates, and achieved reliable detection of malachite green (MG) in clams with a detection limit of 7.8 × 10 −11 M. This work provided a guide to further revise the morphology of heterodimers and a new idea for the use of asymmetric dimers for practically photochemical and biomedical sensing.
研究领域:
分析化学
·
纳米材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）