9 research outputs found
First principles study of electronic and nonlinear optical properties of AâDâÏâA and DâAâDâÏâA configured compounds containing novel quinolineâcarbazole derivatives
Materials with nonlinear optical (NLO) properties have significant applications in different fields, including nuclear science, biophysics, medicine, chemical dynamics, solid physics, materials science and surface interface applications. Quinoline and carbazole, owing to their electron-deficient and electron-rich character respectively, play a role in charge transfer applications in optoelectronics. Therefore, an attempt has been made herein to explore quinolineâcarbazole based novel materials with highly nonlinear optical properties. Structural tailoring has been made at the donor and acceptor units of two recently synthesized quinolineâcarbazole molecules (Q1, Q2) and acceptorâdonorâÏâacceptor (AâDâÏâA) and donorâacceptorâdonorâÏâacceptor (DâAâDâÏâA) type novel molecules Q1D1âQ1D3 and Q2D2âQ2D3 have been quantum chemically designed, respectively. Density functional theory (DFT) and time-dependent density functional theory (TDDFT) computations are performed to process the impact of acceptor and donor units on photophysical, electronic and NLO properties of selected molecules. The λ(max) values (321 and 319 nm) for Q1 and Q2 in DSMO were in good agreement with the experimental values (326 and 323 nm). The largest shift in absorption maximum is displayed by Q1D2 (436 nm). The designed compounds (Q1D3âQ2D3) express absorption spectra with an increased border and with a reduced band gap compared to the parent compounds (Q1 and Q2). Natural bond orbital (NBO) investigations showed that the extended hyper conjugation and strong intramolecular interaction play significant roles in stabilising these systems. All molecules expressed significant NLO responses. A large value of ÎČ(tot) was elevated in Q1D2 (23â885.90 a.u.). This theoretical framework reveals the NLO response properties of novel quinolineâcarbazole derivatives that can be significant for their use in advanced applications
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Teaching beyond the walls: A mixed method study of prospective elementary teacher's belief systems about science instruction
This mixed method study investigated K-6 teacher candidates' beliefs about informal science instruction prior to and after their experiences in a 15-week science methods course and in comparison to a non-intervention group. The study is predicated by the literature that supports the extent to which teachers' beliefs influence their instructional practices. The intervention integrated the six strands of learning science in informal science education (NRC, 2009) and exposed candidates to out-of-school-time environments (NRC, 2010). Participants included 17 candidates in the intervention and 75 in the comparison group. All were undergraduate K-6 teacher candidates at one university enrolled in different sections of a required science methods course. All the participants completed the Beliefs about Science Teaching (BAT) survey. Reflective journals, drawings, interviews, and microteaching protocols were collected from participants in the intervention. There was no statistically significant difference in pre or post BAT scores of the two groups; However, there was a statistically significant interaction effect for the intervention group over time. Analysis of the qualitative data revealed that the intervention candidates displayed awareness of each of the six strands of learning science in informal environments and commitment to out-of-school-time learning of science. This study supports current reform efforts favoring integration of informal science instructional strategies in science methods courses of elementary teacher education programs
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New Frontiers in Digital Humanities and the Sciences
Video recording of a presentation session at the 2014 Digital Frontiers Annual Conference. In this session, presenters discuss new frontiers in digital humanities and the sciences
Recent progress in flexible Znâion hybrid supercapacitors: Fundamentals, fabrication designs, and applications
Abstract One of the most exciting new developments in energy storage technology is flexible Znâion hybrid supercapacitors (fâZIHSCs), which combine the high energy of Znâion batteries with highâpower supercapacitors to satisfy the needs of portable flexible electronics. However, the development of fâZHSCs is still in its infancy, and there are numerous barriers to overcome before they can be widely implemented for practical applications. This review gives an upâtoâdate description of recent achievements and underlying concepts in energy storage mechanisms of fâZIHSCs and emphasizes the critical role of cathode, anode, and electrolyte materials systems in speeding the prosperity of fâZIHSCs. The innovative nanostructuredâbased cathode materials for fâZIHSCs include carbon (e.g., porous carbon, heteroatomâdoped carbon, biomassâderived porous carbon, graphene, etc.), metalâoxides, MXenes, and metal/covalentâorganic frameworks, and other materials (e.g., activated carbon, phosphorene, etc.) are mainly focused. Afterward, the latest developments in flexible anode and electrolyte frameworks and impacts of electrolyte compositions on the electrochemical properties of fâZIHSC are elaborated. Subsequently, the advancements based on fabrication designs, including quasiâsolidâstate, micro, fiberâshaped, and all climateâchanged fâZIHSCs, are discussed in detail. Lastly, a summary of current challenges and recommendations for the future progress of advanced fâZIHSC are addressed. This review article is anticipated to further understand the viable strategies and achievable approaches for assembling highâperformance fâZIHSCs and boost the technical revolutions on cathode, anode, and electrolytes for fâZIHSC devices