Activated carbon materials have been playing a significant role in addressing the challenges posed with the ever-increasing demand for alternative clean and sustainable energy technologies. In the ...present study, a facile strategy is proposed for generating porosity in porous carbons by using carton box as the precursor and eutectic NaOH–KOH melt as the activating agent. The prepared carbon materials have a very high specific surface area up to 2731 m2 g−1 with large pore volume of 1.68 cm3 g−1, which is greater than that of only KOH was used at the same mass ratio. Electrochemical studies based on symmetric supercapacitor devices demonstrating that the NaOH–KOH melt activated porous carbon exhibits significantly improved rate capability in the range of 0.5–75 A g−1 despite of the similar specific capacitance with respect to KOH activated carbon at a low current density of 0.5 A g−1. The remarkable deviations in capacitive behavior at high current density for the NaOH–KOH melt activated porous carbon and KOH activated samples highlighting the specific surface area is not the only parameter that determines the capacitive performance especially at high charge–discharge rate.
•Activated carbons were prepared using carton box as the precursor.•Eutectic NaOH–KOH melt activated carbon shows better graphitization.•Both large specific capacitance and excellent rate capability were achieved.•The high surface area and mesoporosity is beneficial for ion adsorption and diffusion.
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•A ZnO-coated cotton fibers with superhydrophobicity were fabricated.•The coated fibers can continuously separating a large amount of oils from water.•The coated fibers exhibited good ...separation property for the emulsified oil droplets.
In this study, superhydrophobic and superoleophilic cotton fibers are fabricated by simple one-step hydrothermal route followed by modification with silane. The obtained fibers show selective sorption ability to the oils from water, high sorption capacities, excellent recyclability, and quick sorption rate. The fibers also exhibit outstanding superhydrophobic stability under a variety of corrosive solutions and hot water, which enables it application for the separation of the oils from harsh water environments. Moreover, the superhydrophobic fibers in conjunction with a tube (valid tube area: 0.5cm2) that connected to a vacuum system (vacuum pressure: 0.03MPa) is capable of collecting up to 200 times its self-weight in gasoline within 20s. The coated fibers can also selectively harvest oils from oil/water mixtures under extreme turbulent condition. More importantly, the coated fibers can separate micron-sized oil droplets from oil-in-water emulsions with a high separation efficiency (transparency for solvent oils: >91%) that is beyond what can be obtained by most traditional separation methods. All these performances make the as-prepared cotton fibers ideally suited for the oil-spill cleanups and water purification.
Mg–RE alloys are high-strength magnesium alloys with great application potential. The solidification pathways and microstructure formation of most Mg–RE alloys are still under discussion. In the ...present research, phase constitution and solidification characteristics of Mg–5Gd–2Y–
x
Nd–Zr (
x
= 0, 2, 4, 6) alloys were investigated using a Computer-Aided Cooling Curve Analysis (CA-CCA) system, together with microstructure observation and phase identification methods including SEM, EDS, and XRD. The results show that the solidification microstructure of Mg–5Gd–2Y–Zr alloy was composed of
α
-Mg and Mg
24
RE
5
phase. And the addition of Nd leads to the formation of
β
phase through a eutectic reaction, L → Mg
24
RE
5
+
α
-Mg +
β
. Combining the CA-CCA and microstructure observation results, the non-equilibrium solidification route and solid fraction–time relationship of Mg–5Gd–2Y–
x
Nd–Zr (
x
= 0, 2, 4, 6) alloys was summarized. Besides, hot tearing susceptibility of the investigated alloys was evaluated according to their solid fraction–time relationship using Clyne–Davies’ criterion.
Energy-related CO2 emissions are mainly concentrated in urban areas. Quantitative research on the relationship between CO2 emissions and economic growth at city and sub-city level is of great ...importance. Based on the Tapio’s decoupling model, this paper analyzes the decoupling status of CO2 emissions from economic growth in the 16 districts of Beijing during the period of 2006–2017. The decoupling state of the 16 districts showed obvious phased improvement characteristics. In 2017, 93.75% districts achieved decoupling state, including strong decoupling and weak decoupling, of CO2 emissions from economic growth and 37.50% districts achieve strong decoupling, the most desirable decoupling state. The effect of urban functional zoning and industrial structure transition on the total CO2 emissions and the direct influences of the national environmental protection policies and big public event on the decoupling of CO2 emissions from economic growth were observed. This study will enrich the body of decoupling research at the district level and will provide scientific support to the achievement of the “double carbon” target in Beijing and other Chinese cities.
•Uncover the decoupling status of CO2 emission from economic growth at district level.•Observe the big public events’ effects on carbon decoupling in Beijing.•Reveal the spatiotemporal characteristics of CO2 emissions by functional zone.
High-entropy alloys (HEAs), which were introduced as a pioneering concept in 2004, have captured the keen interest of numerous researchers. Entropy, in this context, can be perceived as representing ...disorder and randomness. By contrast, elemental compositions within alloy systems occupy specific structural sites in space, a concept referred to as structure. In accordance with Shannon entropy, structure is analogous to information. Generally, the arrangement of atoms within a material, termed its structure, plays a pivotal role in dictating its properties. In addition to expanding the array of options for alloy composites, HEAs afford ample opportunities for diverse structural designs. The profound influence of distinct structural features on the exceptional behaviors of alloys is underscored by numerous examples. These features include remarkably high fracture strength with excellent ductility, antiballistic capability, exceptional radiation resistance, and corrosion resistance. In this paper, we delve into various unique material structures and properties while elucidating the intricate relationship between structure and performance.
Purpose
Solving the two major dilemmas of stress shielding and secondary surgery faced by permanent biomedical metal implants.
Methods
We discuss a study on Ca53+xMg20Zn27-x (x=0,2,4,6,8,10) alloys, ...focusing on changes in Zn content near eutectic points and their impact on microstructure and biological corrosion behavior. A copper mold spray casting method has been developed to prepare amorphous bar alloys and amorphous crystalline composite bar alloys with a diameter of 3 mm, which has been verified by electrochemical treatment and other tests.
Results
The Ca63Mg20Zn17 alloy showed the best glass-forming ability, while the Ca59Mg20Zn21 alloy exhibited superior corrosion resistance. Additionally, the study suggests that the corrosion resistance of Ca-based amorphous crystalline composite alloys increases when the Zn content decreases.
Conclusions
At constant Mg, the GFA of Ca53+xMg20Zn27-x (x=6, 8, and 10) increased with the decrease of Zn content, indicating an increase in Ca content. In simulated body fluid (SBF) at 37 ℃, the corrosion resistance of Ca53+xMg20Zn27-x (x=0, 2, and 4) composite alloy bars increase with the decrease of Zn content, while the corrosion resistance of Ca53+xMg20Zn27-x (x=6, 8, and 10) BMGs bars decrease with the decrease of Zn content. The corrosion performance of Ca57Mg20Zn23 composite bar is better than that of the completely amorphous Ca59Mg20Zn21 amorphous bar, because a small amount of crystal phase in the amorphous bar acts as anode, protecting the amorphous matrix and improving the corrosion resistance of the system. The cytotoxicity test shows that Ca-Mg-Zn alloy has good biocompatibility and can be utilized as a biomedical material.
In this study, pulse currents with different peak densities were applied on hypermonotectic Cu-40 wt.% Pb alloy during the cooling process. The microstructures of the alloy before and after the ...application of pulse currents were compared to explore the influences of pulse currents on solidification microstructures of the alloy. The comparison results indicated that pulse currents could decrease the activity of clusters inside the alloy melt, enhance the solvent effect, and reduce the volume fraction of the second phase, thus inhibiting liquid phase separation and achieving the control of the solidification structure of the alloy.
The solidification behavior and solidification structure evolution of Cu-37.4wt%Pb undercooled melt under different undercoolings were studied by the combination of molten glass purification and ...cyclic superheating. With the increase in the undercooling, the solidification microstructure undergoes the coarse-fine-coarse-layered transition process and the distribution of Pb particles in the solidified structure is changed accordingly. With the distribution function of the second phase droplet under the combined action of nucleation, growth and deposition, the range for the critical undercooling of undercooled melt required for realizing the homogeneous solidification is obtained by solving and simplifying the function and then experimentally verified.
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•Breast cancer cases and deaths in the WPR are expected to continue to increase between 2020 and 2044.•Among behavioral and metabolic factors, the main risk factors for BC mortality ...in middle-income countries were high body-mass index, whereas in Japan, the main risk factor was alcohol use.•Age is a key factor in the development of BC, with 40 years being the critical point.•Incidence trends of BC coincide with the course of economic development.•The majority of the breast cancer burden in the WPR comes from middle-income countries.
Breast cancer (BC) is a malignant disease that occurs worldwide and poses serious health burden.
To assess the prevalence of BC burden in the Western Pacific region (WPR) from 1990 to 2019, and to predict trends from 2020 to 2044. To analyze the driving factors and put forward the region-oriented improvement.
Based on the Global Burden of Disease Study 2019, BC cases, deaths, disability-adjusted life years (DALYs) cases, age-standardized incidence rate (ASIR), age-standardized death rate (ASDR), and age-standardized DALYs rate in WPR from 1990 to 2019 was obtained and analysed. Age-period-cohort (APC) model was used to analyze age, period, and cohort effects in BC, and Bayesian APC (BAPC) was used to predict trends over the next 25 years.
In conclusion, BC incidence and deaths in the WPR have increased rapidly over the past 30 years and are expected to continue to increase between 2020 and 2044. Among behavioral and metabolic factors, high body-mass index was the main risk factor for BC mortality in middle-income countries, whereas alcohol use was the main risk factor in Japan. Age is a key factor in the development of BC, with 40 years being the critical point. Incidence trends coincide with the course of economic development.
The BC burden remains an essential public health issue in the WPR and will increase substantially in the future. More efforts should be made in middle-income countries to prompt the health behavior and minimize the burden of BC because these nations accounts for the majority of BC burden in the WPR.
Naked Co68.25Fe4.5Si12.25B15 metal fibers with diameter from 25 µm to 100 µm are produced by melt extraction method. Significant diameter dependence of magnetic properties is studied. Their ...microstructure and magnetic properties of hysteresis loops and giant magneto impedance (GMI) effect at frequencies from 0.1MHz to13MHz are investigated. The results show that the coercivity increases with the diameter of fibers and the GMI effect is best in fiber with a diameter of 35µm. It is found that the cooling rate of solidification decreases with the increase of fiber diameter. And fibers are amorphous with the diameter of 50µm and there are nanocrystallines in fibers with a diameter of 85µm. The grain boundary blocks the magnetization process which makes lower circular permeability, larger coercivity and lower field sensitivity of GMI effect. The original microstructure of Co-based fibers decides their magnetic properties. Therefore, material design is important to improve the GMI effect in magnetic field sensor making.
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