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As an ambitious strategy of national interest in China and with an aim at achieving the ‘one-hour economic circle’ among Greater Bay Area cities by 2035, the Guangdong-Hong Kong-Macao Greater Bay Area has been transformed into a world-class bay economic belt in South China. Consequently, the large-scale construction of transportation infrastructure inevitably resulted in the consumption of a lot of resources and significant environmental impact. Such a scenario could produce conflicts with Greater Bay Area’s commitment on the sustainable development goal, such as China’ carbon intensity reduction. In this study, the environmental impacts caused by highway pavement in Greater Bay Area at urban agglomeration level were quantified through life cycle assessment method, measured by greenhouse gas emissions (CO2eq). Our results show that the total emissions resulted from the use of materials during the construction of highway pavement, its maintenance, and rehabilitation phases in Greater Bay Area reached 4.4 (± 0.25) million tonnes CO2eq in 2018, of which material phase (material production and transportation to the construction site) accounted for more than 70% of the total impact. The construction phase of asphalt pavement is larger than the maintenance and rehabilitation phase, while the maintenance and rehabilitation phase of cement concrete pavement is larger than the construction phase. Moreover, a scenario-based analysis implies that the continuing growth of highway mileage in Greater Bay Area will accelerate the environmental impact till 2035. These findings can help understand the impacts of highway pavement in Greater Bay Area and provide useful support for policy-makers. In addition, the methods are useful for the quantification of greenhouse gas emissions of highway construction on city level in China and beyond.

In this article, the phase compositions, microstructures, and magnetic properties of PrNd-free Ce-Fe-B-based sintered magnets with the nominal composition of (Ce0.78Y0.17La0.05)16.28Febal.B7.44M1.94 (at.%: M = Co, Al, Cu, and Nb) have been investigated. It shows that a lamellar crystalline structure is formed in the Ce-Fe-B-based strip casting (SC) alloy. The Y-substituted Ce-Fe-B-based SC alloy is mainly composed of R2Fe14B and RFe2 phases. It suggests that Y substitution is helpful for depressing the $\alpha $ -Fe phase generated in the SC alloy. The island-like intermediate phases exist in the RFe2 region, which are probably caused by the incomplete peritectic reaction during alloy solidification. The Curie temperature $T_{\mathrm {c}}$ of the Y-substituted Ce-Fe-B-based alloy is about 463 K, which is higher than that of the Ce2Fe14B compound ( $T_{\mathrm {c}} =424$ K). For the experimental Ce-Fe-B-based sintered magnet without PrNd addition, the remanence $B_{\mathrm {r}}$ of 8.31 kG, the coercivity $H_{\mathrm {cj}}$ of 0.92 kOe, and the maximum energy product (BH)max of 5.30 MGOe have been obtained. A good combination of coercivity $H_{\mathrm {cj}}$ (= 5.57 kOe) and maximum energy product (BH)max (= 20.17 MGOe) has been achieved in the Ce-Fe-B-based blended magnet with PrNd/ $\sum $ RE = 25% prepared using a binary main phase (BMP) method. The heterogeneous elemental distributions and microstructure characteristics of the BMP magnet are also analyzed.

Human activities during each phase of coal mine life cycle greatly affect groundwater environment. The groundwater environment destruction is not just only the destruction of underground structure but also the social problems caused by available groundwater resources reduction, as well as the environmental problems affecting ecosystem and human health. Moreover, the groundwater environmental risk of coal mining is complex, dynamic, and long-term. Therefore, a framework and quantitative method for groundwater environmental risk analysis at different phases of the mine life cycle was presented, which is composed of the groundwater system destruction risk (GSDR) and social-economic-ecological vulnerability (SEEV) assessment. The framework was applied in Hongshan abandoned coal mine, North China. Based on the aquifer structure destruction, groundwater flow field evolution, contamination, and social-economic influence analysis, 12 main controlling factors for the GSDR and 7 factors for the SEEV were determined and quantified separately. The results showed that the groundwater contamination of the Hongshan mine mainly occurred after closure, caused by the cross-strata pollution of mine water, which significantly reduced the groundwater available resources, which greatly affected local social-economy sustainable development and residents’ health. The Hongshan mine closure increased groundwater environmental risk, with the GSDR high-risk zone being 12.51 km2 larger than that during the mining phase and the SEEV was calculated at a high level. This framework promotes systematic integration of the groundwater environmental risk assessment in mine life cycle.

Life cycle assessment can support decisions for improving the environmental performance of construction products. However, the amount of data required for developing life cycle inventories limits the adoption of LCA. This work associates the interpretation of the impact results of construction products at the unit process level with a quantitative definition for the foreground and background system, for guiding primary data collection towards foreground processes that can be affected by decision-makers in the construction sector. A set of construction products commonly used in Brazil is selected, and their cradle-to-gate life cycle inventories are modeled using the ecoinvent database (version 2). Life cycle impact assessment is performed using the ReCiPe Midpoint Hierarchist method. The contribution of each process during the life cycle of construction products for each impact category is quantified. These processes are associated with economic sectors, which are classified as belonging to the foreground or background system from the perspective of the construction industry. Foreground sectors are those controlled or influenced by the construction sector and are defined based on the production share consumed by the construction value chain. The elementary flows defining each impact category are also identified. Foreground processes show significant contributions to most impact results of construction products. Global warming, fine particulate matter formation, ozone formation, acidification, human carcinogenic toxicity, and terrestrial ecotoxicity are mainly caused by direct emissions and fossil fuel combustion in manufacturing processes. Land occupation for production activities contributes to land use change, while the consumption of fuels, raw materials, and water causes fossil and mineral resource scarcity and water consumption respectively. Freshwater and marine ecotoxicities and human non-carcinogenic toxicity have foreground contributions only for steel and copper products due to emissions from the landfilling of mining tails. Ionizing radiation and stratospheric ozone depletion are mostly driven by background processes. A reduced group of elementary flows covers a big share of the environmental impacts of most construction products. The results indicate priorities for life cycle inventory primary data collection of construction products, by focusing on foreground processes and the corresponding elementary flows that cause many of the potential embodied impacts of construction. Increasing the availability of primary data for these processes improves the reliability of LCA-based decisions in the construction sector, especially in countries which still lack local LCI databases.

The interactions between groundwater and its environment was investigated in prairie mining area in this study, through the groundwater system evolutions in mining area before and after the mining actions (from 1973 to 2016) of Yimin coal mine. The results showed that (1) the mining activities of the open-pit coal changed the original reduction environment into the oxidizing environment in the mining area. The pyrite and sulfur-bearing coal in the stratum oxidized, produced acid and triggered a series of subsequent reactions, resulting in the decrease in the pH value of the groundwater in the mining area. The concentration of SO42-, Fe2+, Fe3+, Ca2+ and Mg2+ and the total hardness increased. The regional hydrochemical type evolved from HCO3-Na·Ca·Mg type before mining to the type of HCO3·SO4-Na·Ca·Mg after mining. (2) Coal mining strongly draining underground water accelerated the regional groundwater circulation, and then made the groundwater desalination. The concentrations of TDS, COD and Na++K+ in the mining area all showed a decreasing trend. (3) The coal mining activities made the calcite and dolomite in saturated state under the natural condition of underground water to be unsaturated again. The hydro-geochemical action evolves from double control (water-rock interaction and evaporation-concentration) to water-rock interaction control.

Groundwater plays an important role in water supply and economic development for Yantai city, China. However, the groundwater quality has degraded due to the increase and expansion of agricultural and industrial development. It is urgent to acquire groundwater characteristics and distinguish impacts of natural factors and anthropogenic activities on the groundwater quality. Forty-six groundwater samples collected from different wells showed a great variation of chemical components across the study area. Most wells with higher total dissolved solids, total hardness, K+, Na+, Ca2+, Mg2+, Cl− and SO42− concentrations were located relatively close to the coastal zone. The factor analysis (FA) and hierarchical cluster analysis results displayed that seawater intrusion was the primary mechanism controlling the groundwater quality in the coastal areas. A three-factor model was proposed based on the FA and explained over 85% of the total groundwater quality variation: Factor 1, the seawater intrusion; Factor 2, the water–rock interaction and Factor 3 (NO3−), the human activities. Furthermore, the geographical maps of the factor scores clearly described the spatial distributions of wells affected by natural processes or human activities. The study indicated that both natural processes and human activities are the major factors affecting the chemical compositions of groundwater.

In this paper, dependence of magnetic properties on microstructure and composition of Ce-Fe-B sintered magnets with Cu-doped Ce-rich alloy addition was investigated. It shows that the maximum energy product (BH)max and coercivity Hcj of Ce-Fe-B sintered magnet are improved from 6.76 to 9.13 MGOe by 35.1%, and from 1.44 to 1.67 kOe by 16.0%, respectively, via adding 5 wt% liquid phase alloy of Ce35.58Fe57.47Cu6B0.95 (at%). Compared with the magnet without Ce-rich alloy addition, the volume fraction of the grain-boundary phase with low melting point increases in the magnet with Ce-rich alloy addition, which is beneficial to improving the microstructure and promoting the coercivity enhancement of the magnet. In the Ce-Fe-B magnet with Ce-rich alloy addition, Cu and Ce enrich in the grain boundaries of the magnet after annealing, therefore the as-annealed magnet has a higher coercivity than the as-sintered magnet. A distinct Fe-rich layer with the average thickness of 60 nm is found in the grain boundaries in the magnet without Ce-rich alloy addition, but it seems that Fe-rich phase disappears in the magnet with Ce-rich alloy addition. The present work suggests that the further improvement of coercivity in the Ce-Fe-B sintered magnets is expectable by designing the composition and structure of added liquid phase alloys.

Ce-based magnets have attracted extensive attention in both academia and industry due to their excellent property–price ratio and distinctive phase structures. Characteristically, Ce-based sintered magnets have widely tunable magnetic properties with changing Ce contents. Therefore, they can be used to meet many different application requirements from packaging market to driving motors, etc. The intrinsic magnetic properties, phase composition, and microstructures of the Ce-based sintered magnets with different Ce contents have been summarized. The service performances such as temperature stability, corrosion resistance, mechanical properties and thermal expansion of commercial Ce-based sintered magnets are introduced. The research and development trends of the Ce-based magnets in the future are pointed out.

In this article, the phase constitution, microstructures and melting points of Ce35.58Fe63.47-xAlxB0.95 alloys (at.%; x = 0, 3, 5, 10) have been investigated. It indicated that the Ce-rich alloy with x = 0 was mainly composed of CeFe2, Ce2Fe17 and γ-Ce phases. The AlCe3 phase was found in the alloy with x = 3. The microstructures and phase distribution characteristics of the alloys have obviously changed with increasing Al content (x = 5,10). The volume fractions of CeFe2 and Ce2Fe17 decreased. Some dispersed Ce-Al eutectic structures with low melting point were found in the alloy with x = 10. It is showed that the melting points of Ce-rich alloys have a decreasing tendency with increasing Al content, the melting points reduced from 942 °C at x = 0–856 °C at x = 10. Furthermore, the influences of the Ce35.58Fe53.47Al10B0.95 alloy addition on the microstructures and magnetic properties of sintered Ce-Fe-B magnets, were also discussed. The remanence Br slightly decreased, while the intrinsic coercivity Hcj, maximum energy product (BH)m and squareness Hk/Hcj (the ratio of knee coercivity to intrinsic coercivity) of the magnets had significant improvements, and these indexes increased by 8%, 22%, 24%, respectively.

We optimized the hot water extraction of polysaccharides from the root of Henry wood betony (RHWPs) using a uniform test and explored their anti-tumor activities in vitro and in vivo. The optimal extraction conditions were as follows: 40 min extraction time, liquid/solid ratio 30 mL/g, 100 min soaking time, two extraction cycles, 100% ethanol concentration, and extraction temperature of 80 °C. The molecular weight distribution of RHWPs with MWs was 228,600 g/mol and 5001 g/mol. The IR spectrum further indicated that RHWPs are acidic polysaccharides containing pyranose and furan rings. The main monosaccharides found in RHWPs were mannose, ribose, l-rhamnose monohydrate, glucuronic acid, galacturonic acid, glucose, galactose, xylose, arabinose, and fucose. RHWPs inhibited the proliferation of S180 tumor cells and induced apoptosis in vitro. Oral administration of RHWPs to tumor-bearing mice significantly inhibited the growth of the S180 xenografts, accelerated apoptosis in tumor cells, and expanded the necrotic regions. Furthermore, RHWPs also markedly increased the levels of TNF-α, IFN-γ, and IL-2 in the sera of tumor-bearing mice, and activated immune cells such as lymphocytes, NK cells, and macrophages, thereby inducing tumor cell apoptosis. Taken together, RHWPs are a promising anti-tumor agent that ought to be explored further.

Coal mining activities have caused severe disturbances to the regional ecosystem and soil properties. Studying the relationship of vegetation and its below-ground habitat (RVBGH) is of great significance to the coal mine land ecological restoration. To identify the optimal thickness of the soil layer for mine land ecosystem recovery and characterize the changes of the reclaimed soil-vegetation ecosystem, we studied natural and reclaimed grassland at the coal mine of Baorixile, located in Hulunbuir Steppe, Northeastern China. The vegetation and its below-ground habitat (BGH), including “root mass” and soil properties in the soil profile (0–100 cm), were surveyed in the natural and different year-reclaimed grassland. The “root mass” is the part of root system that has the most amounts of root hairs, which is the functional zone for plant growth. The RVBGH was identified by the “root mass” and plant water extraction depth, measured through the isotope δD and δ18O method. Firstly, the BGH of natural grassland was identified as a “double layer” vertical structure, with the “root mass” of 37.11 ± 2.57% fine roots at 0–20 cm range and 30.44 ± 2.67% at 20–40 cm range. The annual and perennial plant “root mass” was found at 0–20 cm and 20–40 cm depth, respectively. Secondly, an optimal thickness of the soil covering of 30–40 cm was proposed for grassland reclamation. Thirdly, along the reclamation chronosequence, the values of the reclaimed vegetation properties (height, density, coverage and diversity) increased and a deep root system was established. The “root mass” increased from one layer to double layer and the amount of total fine roots increased from 1621 ± 231.9 to 4459 ± 456.0. Moreover, the reclaimed soil properties of organic matter, cation exchange capacity, available N and P also increased. The study proposed that vegetation restoration was significantly correlated with its BGH, suggesting that vegetation BGH recovery is crucial in ecological restoration.

Nitrous acid (HONO) is an important precursor of hydroxyl radical (OH) in the atmosphere. It is also toxic to human health. In this work, HONO concentrations were measured in Shijiazhuang using a Monitor for AeRosols and Gases in ambient Air (MARGA) from December 15, 2019 to March 15, 2020, which covered the heavy air pollution season, the Chinese New Year (CNY) vocation and the Corona Virus Disease-19 (COVID-19) lockdown period. During & after CNY overlapping COVID-19 lockdown, the air quality was significantly improved because of both the emission reduction and the increase in diffusion ability of air masses. The mean HONO concentration was 2.43 ± 1.08 ppbv before CNY, while it decreased to 1.53 ± 1.16 ppbv during CNY and 0.97 ± 0.76 ppbv after CNY. The lockdown during & after CNY reduced ~31% of ambient HONO along with ~62% of NO and ~36% of NO2 compared with those before CNY after the improvement of diffusion ability had been taken into consideration. Heterogeneous reaction of NO2 on ground surface dominated the nocturnal HONO sources, followed by heterogeneous reaction on aerosol surface, vehicle emission, reaction between NO and OH and emission from soil on pollution days throughout the observation. Except for elevated soil emission, other nighttime HONO sources and sinks decreased significantly during & after CNY. The relative importance of heterogeneous reaction of NO2 on surfaces further increased because of both the decrease in vehicle emission and the increase in the heterogeneous conversion kinetics from NO2 to HONO during & after CNY., Graphical abstract Unlabelled Image, Highlights • High concentration of HONO was observed from 0.08 to 12.67 ppbv in Shijiazhuang. • Heterogeneous conversion of NO2 to HONO dominated the nighttime HONO source. • The lockdown during & after CNY reduced ~31% of ambient HONO. • Heterogeneous conversion kinetics from NO2 to HONO increased during & after CNY. • The T and aerosol properties promoted conversion of NO2 to HONO during & after CNY.

Critical high-tech minerals (CHTMs) are raw materials that are essential for a future clean-energy transition and the manufacture of high-end products. Cellphones, one of the fastest growing electronic products, contain various CHTMs. Since 2019, India has surpassed the United States to become the second largest smartphone market in the world. An increasing and alarming number of excessive waste cellphones will be generated in India in the near future. In this study, the dynamic material flow analysis approach and the Weibull distribution are adopted to analyze the volumes of accumulated waste cellphones and the contained CHTMs based on the differentiation between smartphones and feature phones in India. Moreover, a market supply model is adopted to predict the future trends of CHTMs in waste cellphones. The results show a general upward tendency of waste cellphone volume in India, which indicates that various CHTMs contained in cellphone waste can be properly reused or recycled. Future implications based on the analysis results are provided for efficient cellphone management in India.

The ecological environment of the ecotone of agriculture–animal husbandry in North China is fragile and the groundwater resources are in short supply, in particular, nitrogen contamination is serious. So, the nitrogen source, distribution and transformation in groundwater need to be investigated. A case study was conducted in Tuoketuo County, Inner Mongolia. Hydro-geological, hydro-geochemical, and quality monitoring of groundwater were investigated in the study area. Altogether, 66 groundwater samples were taken with an equal number from both the unconfined and confined aquifers in the study area. The results show that the ammonium compound (NH4+) was the most prevalent species of nitrogen contamination. Both the irrigations of farmland with contaminated surface water and the excessive usage of chemical fertilizers were probably two major non-point sources of nitrogen contamination. The large-scale dairy farm effluents also play an important role in nitrogen contamination in local areas of an unconfined aquifer. The nitrogen contamination in the confined aquifer was mainly due to the leakage recharge of the contaminated unconfined water. The mean concentrations of NO3−, NO2− and NH4+ in confined aquifer were significantly lower and the areas exceeding the water quality standard were similar but smaller than those in an unconfined aquifer. The spatial distributions, migration and transformation of ammonium (NH4+), nitrate (NO3−) and nitrite (NO2−) in the investigation area were closely related to the characteristics of the groundwater flow system and the hydro-geochemical environment. In the groundwater recharge area, nitrification plays a leading role, with NO3− as the major contaminant. Along the groundwater discharge zone, the denitrification, anammox and dissimilatory nitrate reduction to ammonium (NDRA) processes may occur, causing NH4+ to become the main contaminant. The Cl– contamination was also severe both in unconfined and confined aquifers. High concentrations of NO3− and NH4+ were mainly observed in the groundwater of Ca·Mg–Cl and Na–Cl types. The background type of water for unconfined and confined aquifers was mainly Ca–HCO3. This study will provide helpful information to identify the most contaminated locations in the study area for environmental management in future and provides a reference for preserving the environment of ecologically fragile areas.

Design of highly efficient electromagnetic wave (EMW) absorbing materials with continuous dual-absorption peaks is a hot topic but a challenge in anti-electromagnetic interference and pollution fields. Herein, we developed an interfacial modulation strategy to achieve this goal in dielectric nanocomposite and clarified the interface function and relevant mechanism. Experimentally, CuS/Ag 2 S composite with tunable heterointerface was fabricated by decorating Ag 2 S nanoparticles on CuS flakes via cation-exchange reaction. By changing the Ag 2 S loading, the heterointerface between Ag 2 S and CuS induced strong dielectric resonant peak and improved impedance matching, which resulted in the significant enhancement of EMW absorption and the appearance of continuous dual-absorption peaks in CuS/Ag 2 S composite. With a rather low filler loading of 20 wt% and a thin layer thickness of 2.89 mm, the optimized CuS/Ag 2 S composite exhibited continuous dual-absorption peaks with reflection losses of −47.2 and −20.6 dB, respectively. The proposed interfacial modulation strategy may potentially be used to fabricate other highly efficient dual-absorption absorbers.

The (R,Ce)–Fe–B magnets have been successfully industrialized in recent years. The mechanical property of sintered permanent magnets is one important aspect of their comprehensive performances, which directly influences the service reliability and the production cost. In this paper, the bending strength, fracture toughness, Vickers hardness, and brittleness index of commercial (R1– x Ce x )30.5–31.5Febal.B1M1 magnets with different cerium contents have been investigated. The micro-fractures of the magnets were observed by a scanning electron microscopy equipped with energy dispersive X-ray analysis system. It shows that the bending strength and the fracture toughness of (R,Ce)–Fe–B magnets have a downward tendency with increasing Ce content x, while the Vickers hardness of the magnets varies irregularly with Ce contents in this paper. The optimum mechanical properties have been obtained in the (R1– x Ce x )30.5–31.5Febal.B1M1 magnet with $x = 0.15$ ; the bending strength, fracture toughness and brittleness index of the magnet with $x =0.15$ are obviously superior to those of the ordinary sintered Nd–Fe–B magnets. Some flocculent oxide phases have been discovered in the (R,Ce)–Fe–B magnet with $x = 0.15$ . The flocculent phases may absorb the crack propagating energy, and reduce the stress concentration at a crack tip, which is beneficial to strengthening and toughening of (R,Ce)–Fe–B magnets. However, the mechanical properties are obviously worse for the magnet with $x = 0.45$ (Ce/ $\sum $ RE = 45%). That is probably because the microstructures of the magnet with $x = 0.45$ become deteriorated, in which abnormally large grains have been observed.

Waste Nd–Fe–B sintered magnets (grade 33H) were recycled to manufacture anisotropic sintered magnets by adding Ce-rich alloys. The influences of additive amounts of Ce-rich alloys on the microstructure and magnetic properties of the recycled sintered magnets were investigated. It showed that the recycled sintered Nd–Fe–B magnet without Ce-rich alloy addition has rather lower density; the density of the magnet is slightly raised with increased sintering temperature, but the recycled magnet is prone to oxidation, even cracking. For recycled sintered magnets with Ce-rich alloy addition, the densities of the magnets are upgraded with increasing amounts of Ce-rich alloy, and the magnetic properties are obviously improved. This suggests that Ce-rich alloy plays the important role of sintering-aid in the densification of the recycled magnet. However, the coercivity ( $H_{{\text {cj}}}$ ) of the recycled magnets is decreased, when the additive amounts of Ce-rich alloy are over 8 wt.%. This is probably because excessive Ce-rich alloy addition can cause RE-rich phase aggregation at the triple grain boundary junctions, and deteriorate the microstructure of the recycled magnets. The recycled magnet with 5 wt.% Ce-rich alloy, sintered at 1080 °C, exhibits the following optimal magnetic properties: $B_{r}$ of 11.67 kGs; $H_{{\text {cj}}}$ of 18.94 kOe; and maximum energy product $[(BH)_{\max }]$ of 33.1 MGOe. The magnetic properties of the recycled magnets are comparative to those of the waste magnets. Recycled magnets have a higher coercivity and perfect squareness of demagnetization curve ( $H_{k}/H_{{\text {cj}}} =0.972$ ).

The authors report on a low temperature method for large-scale fabrication of cuprous oxide nanocubes deposited on nitrogen-doped reduced graphene oxide (Cu2O/N-RGO). The material was deposited in a glassy carbon electrode (GCE) where it is found to display enhanced electrocatalytic activity for oxidation of diethylstilbestrol (DES). The morphology and composition of Cu2O/N-RGO were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and energy-dispersive spectroscopy. The results demonstrate that the RGO is doped with 3.5% of nitrogen (atomic ratio), and that nanostructured Cu2O particles with controlled cubical morphology and an average size of about 450 nm have been homogeneously deposited on the surface of N-RGO sheets. The oxidation peak of DES was recorded at 0.315 V (vs. saturated calomel electrode) using differential pulse voltammetry. Under the optimal conditions, the modified GCE displays a linear response in the 0.3 to 150 μM DES concentration range, and the limit of detection is 10 nM. The method was applied to the determination of DES in spiked milk, meat and urine samples and gave excellent selectivity, stability and reproducibility.

Nanoporous carbon decorated with Fe nanoparticles (Fe/C) was prepared via in situ carbonization of Fe precursor-encapsulated Zn-based metal organic framework (ZIF8). In the synthetic process, iron precursor (ferrous salt) was mechanically mixed with pre-synthesized ZIF8 taking advantage of the porous characteristic of ZIF8, and then converted to Fe nanoparticles (NPs) at high temperature. The Fe NPs with low content and small size were uniformly embedded in porous graphitic carbon matrix. When the filler loading of Fe/C composite is as low as 15 wt% in paraffin matrix, the absorber exhibited a minimum reflection loss of −29.5 dB at a thickness of 2.5 mm. The strong absorbing capability together with the lightweight feature is closely associated with the well-designed constituent and structure of the composite, which result in good impedance matching and strong electromagnetic energy loss due to the dual-loss mechanism and the synergistic effect between Fe NPs and carbon matrix. This study not only provides a lightweight electromagnetic wave absorbing material, but also offers a general way to prepare metal NPs-nanoporous carbon composite absorber.

A novel visible-light-responding InVO4-Cu2O-TiO2 ternary nanoheterostructure was designed on the basis of the strategy of energy gap engineering and prepared through ordinary wet chemistry methods. The as-prepared nanoheterostructure was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and diffuse reflectance ultraviolet-visible spectroscopy (UV-vis/DRS). The TEM and HRTEM images of 10%InVO4-40%Cu2O-50%TiO2 confirm the formation of nanoheterostructures resulting from contact of the nanosized TiO2, Cu2O and InVO4 in the size of 5–20 nm in diameter. The InVO4-Cu2O-TiO2 nanoheterostructure, when compared with TiO2, Cu2O, InVO4, InVO4-TiO2 and Cu2O-TiO2, shows significant enhancement in the photocatalytic performance for the degradation of methyl orange (MO) under visible-light irradiation. With a 9 W energy-saving fluorescent lamp as the visible-light source, the MO degradation rate of 10%InVO4-40%Cu2O-50%TiO2 reaches close to 90% during 5 h, and the photocatalytic efficiency is maintained at over 90% after six cycles. This may be mainly ascribed to the matched bandgap configurations of TiO2, Cu2O and InVO4, and the formations of two p-n junctions by the p-type semiconductor Cu2O with the n-type semiconductors TiO2 and InVO4, all of which favor spatial photogenerated charge carrier separation. The X-ray photoelectron spectroscopy (XPS) characterization for the used 10%InVO4-40%Cu2O-50%TiO2 reveals that only a small shakeup satellite peak appears for Cu(II) species, implying bearable photocorrosion of Cu2O. This work could provide new insight into the design and preparation of novel visible-light-responding semiconductor composites.

In this article, evaluations of the microstructure and HRE distribution of grain boundary diffused (GBD) Nd-Fe-B sintered magnets with diffusion time (t) and diffusion depth (d) were investigated. The coercivity (Hcj) first increases and then decreases with increasing t; while the remanence (Br) and the maximun energy product ((BH)m) of GBD magnets have an opposite changing trend. A large amount of Tb diffused into the inner of grains, and formed extensive Tb-rich areas in the surface layer at the beginning of GBD process. This suggests that Tb diffuses not only along grain boundaries, but also via grains in the surface layer because of high concentration gradient of Tb. As the concentration gradient of Tb is reduced, Tb diffuses mainly along grain boundaries. The grain boundary acts as the GBD path, but not as a Tb enriched area. There are two coexisting processes, namely, one process is diffusing from the surface to the inside of the magnet, the other is diffusing from the grain boundaries to the shell, then to the inner of grains. The two diffusion processes cause the changes of microstructure and Tb distribution, thus, the magnetic properties of the GBD samples vary correspondingly.

With the rapid development of urbanization worldwide, there is a large volume of neighborhoods that need to be renewed with various problems such as poor building performance, few public facilities, congested road traffic, unequal living standards, disappearing community culture, and deprived environments. Performance evaluations are considered to be useful tools for ensuring the outcomes of sustainable renewal. Although many research works have assessed the performances of urban renewal projects, evaluations, especially for neighborhood renewal projects, are often overlooked. Besides, it is also hard to find a general standard that is suitable for evaluating the performance of any neighborhood renewal project with a lack of related regulations or codes. Thus, this paper intends to build a framework to assess the relative performances of multiple neighborhood renewal projects through a hybrid AHP-TOPSIS method. A case study in Nanjing, China, is used to show how this framework could be applied to decision-making in order to pursue sustainable neighborhood renewal. The results are expected to provide references for sustainable renewal in each neighborhood. Suggestions related to the findings are proposed to further improve the performances of neighborhood renewal projects, such as establishing a multiple principle&ndash, agent framework, providing a sustainable funding system from both the public and private sector, and implementing multiprogram management measures.

The effects of the fractal characteristics on the dynamic characteristics of the oblique impact system are studied via considering the normal contact stiffness with fractal dimension parameter of the microstructure of the interface in this paper. The normal distribution is used to describe the trend of contact line length. The effects of the position parameters and the scale parameters are analyzed. The simulation results show that the increasing of the interface roughness can make the system response more stable. The system response eventually evolves into chaos as the fractal dimension increases. The system response changes between quasiperiod and chaos affected by the contact line length with a normal random distribution.

In this work, a simple, low-cost and eco-friendly strategy for fabricating the three-dimensional porous nitrogen-doped graphene (3D-N-GN) is demonstrated by combining the hydrothermal assembly and freeze-drying process without using any framework support. The desired features for 3D-N-GN, such as rich macroporosity, nitrogen-doping structure and high active surface area have been confirmed by scanning electron microscopy, X-ray photoelectron spectroscopy and electrochemical techniques, respectively. In comparison with two-dimensional graphene (2D-GN) and nitrogen-doped graphene (2D-N-GN), 3D-N-GN makes a more negative shift in the oxidation peak potential of adenine together with a remarkable increase in the oxidation peak current, highlighting the importance of the nitrogen-doping and 3D construction of the graphene-based support for improving the electrocatalytic performance. It also indicates that 3D-N-GN can be used as an efficient electrocatalyst for adenine sensing. Furthermore, the sensing conditions are optimized and the resulting sensor displays excellent analytical performance in the detection of adenine at low concentrations ranging from 0.02 to 1.20 μM, with a detection limit of 8 nM. Finally, this proposed method not only exhibits preferable reproducibility, stability and adequate sensitivity, but also demonstrates good efficiency in the detection of adenine in biological fluids.

Green roofs are well-known as a sustainable construction practice. Economical benefits of green roofs have been widely discussed by many researchers. This chapter starts with an extensive literature review on the benefits and costs of green roofs. The quantitative estimates of individual and public benefits of green roofs were conducted, and lifecycle costs of green roofs from cradle to grave were analyzed. The net present values per unit area of a green roof were accessed by considering the individual benefits, public benefits, and lifecycle costs. A comparable assessment was performed to evaluate the payback period of green roofs in different markets. The analysis demonstrated that the lifecycle cost of green roofs can be paid back by individual benefits in a mature market. If the public benefits are added into the assessment, the lifecycle cost of green roofs can be retrieved in most of the markets.

Smart city is originally aimed at dealing with various urban problems due to rapid urbanization, like energy shortage, congestion, and environmental pollution. The Chinese government has been devoting to the promotion of smart cities for many years. However, it is unconfirmed whether the city is more resilient with all the modern technologies provided when unexpected predicaments like climate changes or disasters occur. Therefore, it is urgent to consider resilience in the smart city. This paper provides a MCDM approach to assess and rank the resilience of 187 smart cities in China. The results demonstrate that the overall resilience of smart cities is at a relatively low level. There is also a significant unbalance of resilience between smart cities due to different infrastructural, economic, social, institutional, and environmental conditions. The potential links between urban smartness and resilience were also explored, and the results showed significant positive relationship between the smartness of a city and its resilience. Evidence also proved that developing smartness is more or less useful for improving urban resilience. Suggestions such as strengthening the development of infrastructure and economy, and enhancing the multi-stakeholders’ cooperation are proposed to further promote the smart and resilient development in China.

Phosphorylated Radix Cyathulae officinalis Kuan polysaccharides (pRCPS) was prepared according to three-factors, ratio of STMP (%) and STPP (%), reaction time and reaction temperature, and three level L9(34) orthogonal design. The antiviral activity of nine pRCPS (pRCPS1-9) was systematically evaluated by three methods pre-adding mode, mixed mode, and post-adding mode. Cellular activity was tested by the CCK-8 assay. The results showed that the optimal modification conditions were the ratio of STMP (%) and STPP (%) 1:4, reaction time 2h and reaction temperature 65°C. Six pRCPS (pRCPS1-4, pRCPS7, pRCPS9) exhibited significant anti-viral activity in pre-adding mode (P

In this work, the metallic silver and non-metallic nitrogen co-doped reduced graphene oxide (Ag-N-RGO) was first synthesized by a simple and cost-effective strategy, and then a molecularly imprinted polymer (MIP) was formed in situ at the surface of the prepared composite via electropolymerization of o-phenylenediamine in the presence of salbutamol as the template molecule. The electrochemical characterizations demonstrate that the bifunctional graphene-based composite shows improved catalytic performance than that of pristine graphene doped with one-component or none. The MIP sensor based on Ag-N-RGO owns high porous surface structure, resulting in the increased current response and enhanced recognition capacity than that of non-imprinted sensor. The outstanding performance of the developed sensor derives from the combined advantages of Ag-N-RGO with effective catalytic property and MIP with excellent selectivity. Under the optimal conditions, the electrochemical response of the developed sensor is linearly proportional to the concentration of salbutamol in the range of 0.03-20.00µmolL-1 with a low detection limit of 7 nmol L-1. The designed sensor has exhibited the multiple advantages such as low cost, simple manufacture, convenient use, excellent selectivity and good reproducibility. Finally, the proposed method has been extended for the determinations of salbutamol in human urine and pork samples, and the satisfactory recoveries between 98.9-105.3% are achieved.