This contribution introduces a versatile method to prepare a new class of polydiacetylene(PDA)-based material. ZnO nanoparticle is used as a nano-substrate for spontaneous assembling of diacetylene monomer, 10,12-pentacosadiynoic acid, on its surface. An irradiation of the organized assemblies by UV light results in PDA/ZnO nanocomposites with deep blue color. Strong ionic interaction and hydrogen bonding at the ZnO surface restrict the dynamics of alkyl side chains and promote the PDA ordering, which in turn drastically affects its thermochromic behaviors. We have found that the PDA/ZnO nanocomposite exhibits two-steps color transition upon increasing temperature. The first transition of the nanocomposite in aqueous suspension, causing the color change from blue to purple, occurs reversibly at ∼90°C. The transition temperature shifts to ∼100°C when the nanocomposite is embedded in polyvinyl alcohol matrix. Further increasing temperature to 145°C induces the second transition, which causes irreversible color change from purple to red.
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http://dx.doi.org/10.1016/j.jcis.2011.01.028 | DOI Listing |
Ying Yong Sheng Tai Xue Bao
October 2024
School of Resources and Environmental Engineering, Ludong University, Yantai 264025, Shandong, China.
Accurately capturing the spatiotemporal dynamics of regional forest cover and its response to climate change is of great significance for forest resource management and ecological environment protection. We used statistical methods such us linear regression and correlation analysis, as well as remote sensing change monitoring to investigate the spatiotemporal dynamics of forest cover and its response to climate change from 2000 to 2022 in Shandong Province based on MODIS VCF products and meteorological data. The results showed that the forest co-verage and forest area in Shandong Province increased from 43.
View Article and Find Full Text PDFYing Yong Sheng Tai Xue Bao
October 2024
College of Plant Protection, Shandong Agricultural University, Tai'an 271018, Shandong, China.
We investigated the effects of exogenous abscisic acid (ABA) on grain filling, starch accumulation, and endogenous hormones in maize (both the heat-tolerant maize variety Zhengdan 958 (ZD958) and the heat-sensitive variety Xianyu 335 (XY335)) under early post-anthesis high temperature stress by simulating high temperature stress for a period of 6 to 12 days post-anthesis in 2022 and 2023. There were three treatments: spraying water at ambient temperature as the control, spraying water at high temperature, and spraying ABA at high temperature. The results showed that early post-anthesis high temperature stress resulted in a significant reduction in grain weight and yield in maize, with XY335 showing a greater reduction than ZD958.
View Article and Find Full Text PDFGlob Chang Biol
December 2024
Faculdade de Ciências, Instituto Dom Luiz, Universidade de Lisboa, Lisbon, Portugal.
In fire-prone regions such as the Mediterranean biome, fire seasons are becoming longer, and fires are becoming more frequent and severe. Post-fire recovery dynamics is a key component of ecosystem resilience and stability. Even though Mediterranean ecosystems can tolerate high exposure to extreme temperatures and recover from fire, changes in climate conditions and fire intensity or frequency might contribute to loss of ecosystem resilience and increase the potential for irreversible changes in vegetation communities.
View Article and Find Full Text PDFConserv Physiol
December 2024
U.S. Bureau of Reclamation Bay-Delta Office, 801 I St., Suite 140, Sacramento, CA 95814, USA.
Freshwater fishes are increasingly facing extinction. Some species will require conservation intervention such as habitat restoration and/or population supplementation through mass-release of hatchery fish. In California, USA, a number of conservation strategies are underway to increase abundance of the endangered Delta Smelt (); however, it is unclear how different estuarine conditions influence hatchery fish.
View Article and Find Full Text PDFJ Biomed Phys Eng
December 2024
Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Background: T thermometry is considered a straight method for the safety monitoring of patients with deep brain stimulation (DBS) electrodes against radiofrequency-induced heating during Magnetic Resonance Imaging (MRI), requiring different sequences and methods.
Objective: This study aimed to compare two T thermometry methods and two low specific absorption rate (SAR) imaging sequences in terms of the output image quality.
Material And Methods: In this experimental study, a gel phantom was prepared, resembling the brain tissue properties with a copper wire inside.
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