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排序方式: 共有967条查询结果,搜索用时 614 毫秒
961.
The COVID-19 pandemic has been the world's greatest challenge since World War II. As an unprecedented global public health crisis, crisis management teams (CMTs) in the infected countries need to rethink to cope with the similar uncertainty and urgency of the ongoing COVID-19 pandemic. The shared context of COVID-19 allows us to explore a cross-nation study of different constructs and CMT to communicate information about crises with the public effectively. Since the pandemic affected all countries, the comparison is warranted. Can CMTs mitigate the effects of COVID-19? Based on the analysis of China and the US cases, our study explores how shared and common knowledge cognition among crisis responders plays a pivotal role in effective CMTs' communication while technological failures and inadequate information disrupt the system, worsening pandemics like COVID-19. Furthermore, organizational dysfunction, such as institutional fragmentation, regulatory hurdles and bureaucratic arrogance, impede effective communication between CMTs. However, effective coordination and decisive leadership could improve coordination effectiveness and reduce crisis costs. 相似文献
962.
Mina Ravanbakhsh Maryam Ravanbakhsh Hamzeh Ali Jamali Mehdi Ranjbaran Saied Shahsavari Neamat Jaafarzadeh Haghighi Fard 《Water and Environment Journal》2023,37(2):206-217
The microplastic particles (MPs) and effects of storage time and direct sunlight on the MPs in bottled mineral waters were investigated by three experiments conditions. The mean MPs concentration was 63.9 ± 38.9 MPs/L. Pellet forms, white/yellow colour and sizes < 100 μm were predominant MPs, accounted for 35.3%, 51% and 60.2% of the total MPs, respectively. Storage of bottled water under darkness and sunlight caused an increase of 1.5% and 2.5% of MPs pollution, respectively. Also, the estimated daily intake (EDI) of MPs was 2.1, 6.4 and 9.6 MPs/kg BW.day for adults, children and infants, respectively. It is concluded that high storage time and direct sunlight may lead to a greater MPs pollution in mineral water and also high human intake through drinking bottled water. Therefore, it is suggested to reduce the expiry date of the bottled mineral water and avoid sunlight contact before consumption. 相似文献
963.
Jam Bahareh Jamshidi Shekari Farid Andalibi Babak Fotovat Reza Jafarian Vahab Najafi Javad Uberti Daniela Mastinu Andrea 《SILICON》2023,15(3):1235-1245
Silicon - Althought safflower is a tolerant crop against many environmental stresses, but its yield and performance reduce under stress. The aim of this experiment was to investigate the effect of... 相似文献
964.
The network structure, mechanical properties, and thermal gravimetric of epoxy resin filled with plasticized carbon black (CB) have been studied. The effect of CB concentration on composite morphology as well as cross linking density (n), volume fraction of resin (Vr), degree of crystallinity (Xc), mean gap among conductive particles (g), aspect ratio (F), and mechanical property such as modulus of elasticity (Ym), hardness (HA), and elongation at break (EB) have been examined and correlated to establish structure–property relationships. According to the thermal gravimetric analysis, the thermal decomposition of the composite took place at a slightly higher temperature than that of green epoxy. It proved that the inclusion of plasticized CB improves the quality of the network structure and enhances the mechanical properties of the composites. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers. 相似文献
965.
Hichem Boulechfar Farid Berrahil Aissa Boulmerka Abdelkader Filali Mahfoud Djezzar 《亚洲传热研究》2023,52(6):4199-4226
This paper presents a numerical study of buoyancy-driven double-diffusive convection within an elliptical annulus enclosure filled with a saturated porous medium. An in-house built FORTRAN code has been developed, and computations are carried out in a range of values of Darcy–Rayleigh number Ram (10 ≤ Ram ≤ 500), Lewis number Le (0.1 ≤ Le ≤ 10), and the ratio of buoyancy forces N (−5 ≤ N ≤ 5). In addition, three methods are used, namely the multi-variable polynomial regression, the group method of data handling (GMDH), and the artificial neural network (ANN) for the predictions of heat and mass transfer rates. First, results are successfully validated with existing numerical and experimental data. Then, the results indicated that temperature and concentration distributions are sensitive to the Lewis number and thermal and mass plumes are developing in proportion to the Lewis number. Two particular values of Lewis number Le = 2.735 and Le = 2.75 captured the flow's transition toward an asymmetric structure with a bifurcation of convective cells. The average Nusselt number tends to have an almost asymptotic value for Le » 5. For the case of aiding buoyancies N > 1, the average Nusselt Number decreased by 33% when the Lewis number increased to its maximum value. Then, it increased by 10% when the Lewis number increased to Le = 1 for the case of opposing buoyancies N < 1 and then decreased by 33% when the Lewis number increased to its maximum value., contrary to the behavior of the average Sherwood number that increased by 700% for both cases N > 1 and N < 1. New correlations of , and as a function of Ram, Le, and N are derived and compared with GMDH and ANN methods, and the ANN method showed higher performance for the prediction of and with R2 exceeding 0.99. 相似文献
966.
967.
Amjad Farid Chen Zhonghua Abdul Sammed Khan Muhammad Javid Ijaz Ahmad Khan Aqib Ali Khan Zeng Fan Lujun Pan 《Advanced functional materials》2023,33(33):2301727
High fabrication cost, chemical instability, and complex immobilization of enzyme molecules are critical issues of enzyme-based glucose sensors. Designing state-of-the-art, binder-free, and non-enzymatic glucose sensing probes plays an imperative role to cope with the aforementioned issues. 3D carbonaceous nanomaterials coated with transition metal vanadates (TMVs) are a favorable biomimetic platform for glucose quantification. Peculiar hierarchical structure, enhanced conductivity, synergistic interaction, multiple oxidation states, and high catalytic activity would make such composite a potential contender for non-enzymatic glucose sensing. Herein, 3D helical-shaped carbon nanocoils (CNCs) are grown on nickel foam (NF) via chemical vapor deposition method to prepare a robust CNCs/NF scaffold. Then, a hydrothermal route is followed to grow interconnected free-standing Ni3V2O8 nanosheets (NSs) on CNCs/NF scaffold. This novel and binder-free Ni3V2O8 NSs/CNCs/NF hierarchical composite possesses superior electrochemical active area (ECSA) and exceptional electrochemical efficacy. Amperometric analysis exhibits extremely prompt detection time (0.1 s), elevated sensitivity (5214 µA mM−1 cm−2), and low detection limit (0.04 µM). Developed sensor demonstrates appreciable recoveries (93.3 to 103.3%) regarding glucose concentration in human serum. The appealing analytical results show that deployment of a 3D helical-shaped hierarchical smart scaffold can be an effective strategy for developing efficient and advanced non-enzymatic glucose sensors. 相似文献