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61.
Association between smartphone use and head-down tilt posture has not yet been quantitatively evaluated in natural settings. This study aimed to objectively assess the angle and duration of head-down tilt posture of smartphone users during a typical working day via naturalistic data collection. Thirty-one college students conducted their typical school activities while their head posture and smartphone-app usage records were collected simultaneously for 8?hours. Participants spent 125.9?minutes (median usage duration) on their smartphones with significantly larger head-down tilt (p?<?.05) than when they were not using the phone. Head tilt angle greater than 30° was found to be more common when using the phone, while head tilt less than 20° was more common when they were not using the phone. Study findings provide empirical evidence that supports an association between the duration of smartphone use and the intensity of head-down tilt posture.
Practitioner Summary: Head postures of young smartphone users were quantified for 8?hours continuously during a typical workday using a wearable sensor. Participants spent more time in larger head-down tilt postures (greater than 30°) when they were using their smartphones as compared to when they were not using them. 相似文献
62.
Photonic Network Communications - A low complexity carrier phase estimation (CPE) algorithm for M-ary quadrature amplitude modulation (m-QAM) optical communication systems is investigated in this... 相似文献
63.
Baosen Zhang Qiangsheng Dong Naishu Zhu Zhixin Ba Yujun Han Zhangzhong Wang 《摩擦学汇刊》2019,62(2):274-282
A novel FeCrNiMoCBSi amorphous/nanocrystalline coating was fabricated using a plasma spraying process. The coating was dense with a low porosity of approximately 0.99%. The coating consisted of a 67.8 vol% amorphous phase coupled with many nanocrystalline grains that were approximately 5?nm in diameter. The mechanical properties of the as-sprayed coating were determined by nanoindentation measurement, and the tribological behaviors were systematically investigated in a reciprocating sliding contact. The results show that FeCrNiMoCBSi coatings possess superior wear resistance compared to other typically similar Fe-based amorphous coatings. The tribological behaviors evolve with the combination of normal load and sliding velocity. Herein, the dominant wear mechanisms are delamination wear and oxidation wear. With an increase in normal load and sliding velocity, the abrasive wear is gradually weakened, the formation of oxide films on the worn surfaces is facilitated, and wear debris is ground to powder. The oxide films suffer from fatigue wear with induced cracks undergoing reciprocating sliding effects. 相似文献
64.
Han Ho-Sik Yun Hong-Seok Hwang Cheol-Hong 《Journal of Mechanical Science and Technology》2019,33(7):3563-3569
Journal of Mechanical Science and Technology - An experimental study was conducted on the calibration method and measurement error for a plate thermometer (PT) that can replace the heat flux gauge... 相似文献
65.
66.
Min Ye Feng Hu Deshuang Yu Silin Han Linlin Li Shengjie Peng 《Ceramics International》2021,47(13):18424-18432
In high demand is developing trifunctional electrocatalysts to simultaneously drive hydrogen evolution reaction (HER) and oxygen evolution/reduction reaction (OER/ORR) for metal-air batteries and water splitting. Here we develop the carbon nanotubes (CNTs)-grafted FeC/MnO2 nanocomposite catalyst by carbonizing FeMn metal-organic frameworks. The synergistic effect between FeC and MnO2 dominantly contributes the ORR, OER, and HER. The transition metal-mediated growth of CNTs by an in-situ catalysis mechanism enables high electrical conductivity, abundant active sites, as well as efficient reaction pathways. The optimized chemical composite and unique hierarchical structure endow the FeC/MnO2 with low overpotentials for multiply electrochemical reactions. Consequently, the composite catalyst successfully serves as the bifunctional electrode for water splitting with a voltage of 1.66 V at 10 mA cm?2 as well as the cathode for all-solid-state metal-air battery with Pt/C-comparable performance. The advanced transition metal composite presented in this work provides the guidance for rationally developing trifunctional electrocatalysts for efficient integrated energy conversion systems. 相似文献
67.
Machine Learning - Recently, some statistical topic modeling approaches have been widely applied in the field of supervised document classification. However, there are few researches on these... 相似文献
68.
Microbiologically influenced corrosion induced by bacteria has been studied for many years. Corrosion is known to be sensitive to the presence of microalgae, such as Phaeodactylum tricornutum. However, the life activity of P. tricornutum that influences the general and localized corrosion of carbon steel is not fully understood. The current study uses a combination of immersion tests and electrochemical experiments with a detailed surface characterization to reveal the naturally formed corrosion products with/without the presence of P. tricornutum. The results show that samples suffer from pitting corrosion and the averaged pit depths are approximately 15 μm under a light–dark cycle condition or a 24-h constant light condition. Meanwhile, the corrosion products are mainly comprised of γ-FeOOH and Fe3O4 in a constant light condition. However, γ-FeOOH, Fe3O4, and FeCO3 are found in a light–dark cycle. This study proposes the fundamental mechanisms of the effect of P. tricornutum life activities on the corrosion performance of Q235 carbon steel, to fulfill the knowledge gaps of the presence of microalgae inducing the general and pitting corrosion of carbon steel. 相似文献
69.
本文使用Prophet人工智能算法研究与预测移动通信网络“潮汐效应”现象,探索网络“潮汐效应”在优化网络资源配置实现网络降本增效的作用。Prophet人工智能算法是一种简单、有效,且易于实现的人工智能算法。通过facebook的人工智能开源框架fbprophet,研究4G网络PRB利用率等网络资源指标的“潮汐效应”,并预测这些网络资源指标在未来的变化趋势,用来指导当前4G网络减容、扩容和4/5G节电节能等,实现优化网络资源配置达到降本增效的目的。 相似文献
70.
Wenjie Liu Jianmin Liu Shu Xing Xiaobin Li Liwen Han Kechun Liu Tao Wei Mingyang Zhou 《European Journal of Lipid Science and Technology》2021,123(6):2000276
In this study, the anti-atherosclerotic properties of three marine phospholipids (MPLs) extracts from fishery by-products including codfish roe, squid gonad, and shrimp head are verified. Their effects on key factors involved in atherosclerosis are examined and compared to explore whether the differences in their constitutions lead to the differences in the function. All three MPLs dampen oxidation of low- density lipoproteins (LDL) in vitro. Treating RAW264.7 macrophages and HUVECs endothelial cells with each MPLs ranging 10–100 µg mL−1 does not decrease cell viability, yet ox-LDL caused cytotoxicity of both cells are alleviated by 50 or 100 µg mL−1 MPLs treatment. In addition, the three MPLs reduce ox-LDL induced macrophage foam-like transition, mainly through inhibition of lipid uptake. Of the three MPLs, the one from squid gonad exhibits the best effect. On the other hand, all three MPLs modulate inflammatory responses, equally, by inhibiting the adhesion of monocytes to endothelial cells, and decreasing secretion of pro-inflammatory cytokines IL-6 and MCP-1. Using a high-cholesterol diet induced zebrafish model, it is found that all three MPLs, especially the one from squid gonad, alleviates cholesterol accumulation in early plaques, and decreases total cholesterol as well as lipid peroxide in vivo. Practical Applications: As a way of making the best of the increasingly scarce marine resources, valuable lipid components can be recovered from by-products and wastes from the fishery industry. Here, we tested the anti-atherosclerotic effects and the mechanisms of three MPLs extracted from codfish roe, squid gonad, and shrimp head. Our study provides further evidence that marine phospholipids extracted from fishery by-products could protect against atherosclerosis, and helps to elucidate the structure-function relationship of MPLs. 相似文献