Snowflake-Shaped ZnO Nanostructures-Based Gas Sensor for Sensitive Detection of Volatile Organic Compounds

Volatile organic compounds (VOCs) have been considered severe risks to human health. Gas sensors for the sensitive detection of VOCs are highly required. However, the preparation of gas-sensing materials with a high gas diffusion performance remains a great challenge. Here, through a simple hydrothermal method accompanied with a subsequent thermal treatment, a special porous snowflake-shaped ZnO nanostructure was presented for sensitive detection of VOCs including diethyl ether, methylbenzene, and ethanol. The fabricated gas sensors exhibit a good sensing performance including high responses to VOCs and a short response/recovery time. The responses of the ZnO-based gas sensor to 100 ppm ethanol, methylbenzene, and diethyl ether are about 27, 21, and 11, respectively, while the response times to diethyl ether and methylbenzene are less than 10 seconds. The gas adsorption-desorption kinetics is also investigated, which shows that the gas-sensing behaviors to different target gases are remarkably different, making it possible for target recognition in practical applications

The Sihailongwan Maar Lake, northeastern China as a candidate Global Boundary Stratotype Section and Point for the Anthropocene Series

Sihailongwan Maar Lake, located in Northeast China, is a candidate Global boundary Stratotype Section and Point (GSSP) for demarcation of the Anthropocene. The lake’s varved sediments are formed by alternating allogenic atmospheric inputs and authigenic lake processes and store a record of environmental and human impacts at a continental-global scale. Varve counting and radiometric dating provided a precise annual-resolution sediment chronology for the site. Time series records of radioactive (239,240Pu, 129I and soot 14C), chemical (spheroidal carbonaceous particles, polycyclic aromatic hydrocarbons, soot, heavy metals, δ13C, etc), physical (magnetic susceptibility and grayscale) and biological (environmental DNA) indicators all show rapid changes in the mid-20th century, coincident with clear lithological changes of the sediments. Statistical analyses of these proxies show a tipping point in 1954 CE. 239,240Pu activities follow a typical unimodal globally-distributed profile, and are proposed as the primary marker for the Anthropocene. A rapid increase in 239,240Pu activities at 88 mm depth in core SHLW21-Fr-13 (1953 CE) is synchronous with rapid changes of other anthropogenic proxies and the Great Acceleration, marking the onset of the Anthropocene. The results indicate that Sihailongwan Maar Lake is an ideal site for the Anthropocene GSSP

Chinese Women’s Concept of Childbirth Based on the Social Media Topic “What Does Childbirth Mean to a Woman”: Content and Thematic Analysis

BackgroundIn recent years, women’s fertility desire has attracted increasing attention in China. ObjectiveThis study aims to detect attitudes toward giving birth among young female users on Douban, a very popular Chinese social media platform. MethodsA total of 2634 valid posts from 2489 users discussing the topic “What does childbirth mean to a woman” on Douban were crawled and retained for analysis. We utilized content and thematic analysis methods to capture users’ concepts of childbirth. ResultsThe findings reveal that a significant majority of users conveyed generally neutral (1060/2634, 40.24%) or negative (1051/2634, 39.90%) attitudes toward childbirth, while only about one-fifth of users expressed positive (523/2634, 19.86%) sentiments. Notably, posts with negative attitudes garnered more replies and likes, and the proportion of posts expressing negativity exhibited fluctuations over time. Health risk (339/2634, 12.87%) emerged as the most frequently cited aspect of childbirth cost, with subjective happiness and the fulfillment of mental needs identified as primary benefits. Surprisingly, only a minimal number of posts (10/2634, 0.38%) touched upon the traditional objective benefits of raising children for old-age care. Thematic analysis results suggest that discussions about fertility on social media platforms might contribute to an exaggerated perception of health risks among women. Additionally, a lack of knowledge about childbirth was observed, partially attributable to longstanding neglect and avoidance of communication on these matters, likely influenced by traditional cultural biases. Moreover, there is a prevailing assumption that women should naturally sacrifice themselves for childbirth and childcare, influenced by the idealization of the female figure. Consequently, women may harbor hesitations about having a baby, fearing the potential loss of their own identity in the process. ConclusionsThe results indicate a shift in the perception of childbirth among modern Chinese women over time, influenced by their increasing social status and the pursuit of self-realization. Implementing strategies such as public education on the health risks associated with pregnancy and delivery, safeguarding women’s rights, and creating a supportive environment for mothers may enhance women’s willingness to undergo childbirth. International Registered Report Identifier (IRRID)RR2-10.2196/preprints.5046

Environmentally Friendly and Cost-Effective Synthesis of Carbonaceous Particles for Preparing Hollow SnO2 Nanospheres and their Bifunctional Li-Storage and Gas-Sensing Properties

The templated preparation of hollow nanomaterials has received broad attention. However, many templates are expansive, environmentally-harmful, along with involving a complicated preparation process. Herein, we present a cost-effective, environmentally friendly and simple approach for making carbonaceous particles which have been demonstrated as efficient templates for preparing hollow nanospheres. Natural biomass, such as wheat or corn, is used as the source only, and thus other chemicals are not needed. The carbonaceous particles possess abundant hydroxyl and carboxyl groups, enabling them to efficiently adsorb metal ions in solution. The prepared SnO2 hollow spheres were used in a lithium-ion (Li-ion) battery anode, and as the sensing layer of a gas sensor, respectively. After charge–discharge for 200 times at a rate of 1 C, the anodes exhibit a stable capacity of 500 mAh g−1, and a Coulombic efficiency as high as 99%. In addition, the gas sensor based on the SnO2 hollow spheres shows a high sensing performance towards ethanol gas. It is expected that the presented natural biomass-derived particles and their green preparation method will find more applications for broad research fields, including energy-storage and sensors

A lamellar V2O3@C composite for aluminium-ion batteries displaying long cycle life and low-temperature tolerance

Rechargeable aluminum-ion (Al-ion) batteries have important potential for fast charging and safe energy-storage systems. Here, we develop a composite composed of lamellar V2O3@C nanosheets, which displays high electrochemical properties as an Al-ion battery cathode. The unique structure is conducive to the rapid insertion and release of Al3+ ions, electrolyte infiltration, and improved conductivity. After cycling 500 times, the capacity exceeds 242.5 mA h g(-1). Under a low temperature of -10 degrees C, the capacity remains 150.8 mA h g(-1), and the Coulombic efficiency is higher than 98.8%. The V2O3@C also exhibits a good reversibility verified by using ex situ X-ray powder diffraction patterns, while the constant current intermittent titration technology shows a low reaction barrier, which indicates that the lamellar composite presented here could find significant applications for engineering many high-performance energy-storage systems

Co-coating ZnCo2O4 and carbon on a biomimetic sea anemone-shaped SnO2 mesostructure for high-performance lithium-ion batteries and semi-solid lithium slurry batteries

Biomimetic materials are receiving increasing attention as potential candidates for secondary battery systems owing to unique structures and properties. Here, we develop a biomimetic composite composing of sea anemone-shaped hollow SnO2 in-situ co-coating with ZnCo2O4 nanoparticles encapsulated by a carbon shell. The bio-mimetic SnO2@ZnCo2O4@C-based Li-ion battery anode shows a stable capacity of 700 mAh g(-1) after 350 cycles, a Coulombic efficiency exceeding 99% and a repeatable rate-performance. Low reaction barriers and rapid diffusion kinetics of Li ions are verified by using galvanostatic intermittent titration technique analysis. More -over, a full cell composing of a SnO2@ZnCo2O4@C anode and a LiCoO2 cathode exhibits 520 mAh g(-1); while working as a slurry battery anode, the sea anemone-shaped SnO2@ZnCo2O4@C also displays high capacity and Coulombic efficiency after 100 cycles. The high performances of the biomimetic composite when working at different battery systems enable it to be applicable broadly

Co-coating ZnCo2O4 and carbon on a biomimetic sea anemone-shaped SnO2 mesostructure for high-performance lithium-ion batteries and semi-solid lithium slurry batteries

Biomimetic materials are receiving increasing attention as potential candidates for secondary battery systems owing to unique structures and properties. Here, we develop a biomimetic composite composing of sea anemone-shaped hollow SnO2 in-situ co-coating with ZnCo2O4 nanoparticles encapsulated by a carbon shell. The bio-mimetic SnO2@ZnCo2O4@C-based Li-ion battery anode shows a stable capacity of 700 mAh g(-1) after 350 cycles, a Coulombic efficiency exceeding 99% and a repeatable rate-performance. Low reaction barriers and rapid diffusion kinetics of Li ions are verified by using galvanostatic intermittent titration technique analysis. More -over, a full cell composing of a SnO2@ZnCo2O4@C anode and a LiCoO2 cathode exhibits 520 mAh g(-1); while working as a slurry battery anode, the sea anemone-shaped SnO2@ZnCo2O4@C also displays high capacity and Coulombic efficiency after 100 cycles. The high performances of the biomimetic composite when working at different battery systems enable it to be applicable broadly

A lamellar V2O3@C composite for aluminium-ion batteries displaying long cycle life and low-temperature tolerance

Rechargeable aluminum-ion (Al-ion) batteries have important potential for fast charging and safe energy-storage systems. Here, we develop a composite composed of lamellar V2O3@C nanosheets, which displays high electrochemical properties as an Al-ion battery cathode. The unique structure is conducive to the rapid insertion and release of Al3+ ions, electrolyte infiltration, and improved conductivity. After cycling 500 times, the capacity exceeds 242.5 mA h g(-1). Under a low temperature of -10 degrees C, the capacity remains 150.8 mA h g(-1), and the Coulombic efficiency is higher than 98.8%. The V2O3@C also exhibits a good reversibility verified by using ex situ X-ray powder diffraction patterns, while the constant current intermittent titration technology shows a low reaction barrier, which indicates that the lamellar composite presented here could find significant applications for engineering many high-performance energy-storage systems