Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 47
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Adv Healthc Mater ; : e2304573, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38558375

RESUMO

In clinical treatments, reliable flow rate measurements ensure accurate drug delivery during infusions, precise gas delivery during artificial ventilations, etc., thereby reducing patient morbidity and mortality. However, precise flow rate sensors are costly, so medical devices with limited budgets choose cheaper but unsatisfactory flow rate measurement approaches, leading to increased medical risks. Here, a photoelectric flow rate sensor based on a flexible planar curved beam structure (FPCBS) is proposed. The FPCBS ensures low out-of-plane stiffness of the sensitive sheet and allows large deformation in the elastic range, enabling the flow rate sensor to measure the flow rate with high sensitivity over a wide range. Meanwhile, the flow rate sensor can be mass-produced using mature materials and manufacturing technology at less than $5 each. The flow rate sensors are integrated into a commercial infusion pump to measure drug infusion and a home ventilator to monitor respiration. The results are comparable to those measured by a commercial flow rate sensor, demonstrating the applicability of the sensor. Considering its proven outstanding performance at low cost, the flow rate sensor shows great potential in clinical treatment, medical diagnosis, and other medical fields.

2.
Micromachines (Basel) ; 15(3)2024 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-38542618

RESUMO

In recent years, global attention towards new energy has surged due to increasing energy demand and environmental concerns. Researchers have intensified their focus on new energy, leading to advancements in technologies like triboelectrification, which harnesses energy from the environment. The invention of the triboelectric nanogenerator (TENG) has led to new possibilities, with the rotary sliding TENG standing out for its superior performance. However, understanding its mechanical behavior remains a challenge, potentially leading to structural issues. This paper introduces a novel analytical mechanics model to analyze the mechanical performance of the stator of the rotary sliding TENG, offering a new analytical solution. The solution also presents an innovative approach to solving axisymmetric problems in elasticity theory since it challenges a traditional assumption that the stress function depends solely on the radial coordinate, proposing a new stress function to derive a more general solution, supplementing the classical approach in the theory of elasticity. Through the obtained solutions, the mechanical characteristics of the rotary sliding TENG during operation are analyzed. A clearer relationship between mechanical characteristics and electrical output is expected to provide a theoretical basis for the design of the rotary sliding TENG.

3.
Environ Pollut ; 341: 123012, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38008254

RESUMO

Microplastics (MPs) refer to plastic particles with a size less than 5 mm, which attracted widespread attention as an emerging pollutant. The monitoring of atmospheric microplastics (AMPs) in a megacity was carried out to study the characteristics and spatiotemporal distribution of AMPs, explore the sources and estimate the deposition flux. The results showed that the annual average abundance of AMPs in Wuhan was 82.85 ± 57.66 n·m-2·day-1. The spatiotemporal distribution characteristics of AMPs show that spring was the highest season, followed by autumn, winter, and summer; the city center was higher than the suburbs. Fiber was the main type of AMPs in Wuhan, followed by fragment, film and pellet. The proportion of AMPs were mainly small (<0.5 mm) and medium (0.5-1.0 mm). Transparent and white were the main colors of AMPs, followed by red, brown. A total of 10 types polymers were detected, polyethylene terephthalate (PET) was dominant. There are positive correlations between AMPs and SO2, NO2 in the atmosphere, indicating that they might be influenced by intense human activity. The polycyclic aromatic hydrocarbons (PAHs) and AMPs in spring showed an extremely significant positive correlation (p < 0.05). AMPs might mainly originate from the wear and tear shedding of textiles, the aging of agricultural films and plastic waste based on their polymer types and main uses. The potential geographical sources of AMPs were mainly the surrounding cities. The annual deposition flux of AMPs was about 308 tons if there were no remove processes, which highlighted the importance of atmospheric transport and deposition of MPs. The analysis of the abundance, morphological characteristics and sources of AMPs can provide data support and reference for mega-cities with high global population activities, or cities in global mid-latitude regions.


Assuntos
Poluentes Atmosféricos , Poluentes Químicos da Água , Humanos , Microplásticos/análise , Plásticos , Cidades , Monitoramento Ambiental/métodos , Poluentes Atmosféricos/análise , Poluentes Químicos da Água/análise
4.
Environ Res ; 239(Pt 1): 117380, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37832771

RESUMO

Deciphering the temporal patterns of polycyclic aromatic hydrocarbons (PAHs) in sediment cores, and the effect mechanism of sedimentary organic matter (OM) and regional development model on PAHs are crucial for pollution control and environmental management. Herein, sediment core was collected from Chenhu international wetland in Wuhan, central China. Meanwhile, historical trend and source of PAHs and sedimentary OM were presented, respectively. Result demonstrated that the most significant growth of PAHs (increased by 158.8%) was attributed to the significant enhancement of traffic emission (5.57 times), coal combustion (4.59 times), and biomass burning (8.09 times). Similarly, the percentage of phytoplankton (stage Ⅲ: 37.9%; stage Ⅳ: 31.2%) and terrestrial C3 plants (stage Ⅲ: 24.6%; stage Ⅳ: 29.2%) to sedimentary OM hold the dominant position after the stage Ⅱ. The obvious shifts of historical trend and sources in PAHs were highly related to economic development models (r = 0.72, p < 0.001) and sedimentary OM (r = 0.82, p < 0.001). It demonstrated that eutrophication of lake accelerated the burial of PAHs. Redundancy analysis results suggested that TOC was dominating driver of sedimentary PAHs (16.56%) and phytoplankton occupied 9.58%. To further confirm the significant role of economic development models, three different historical trends of PAHs in different regions of China were presented. The result of this study provides the new insight into the geochemistry mechanism of lake sedimentary OM and PAHs. Meanwhile, the relationship of regional development model and sedimentary PAHs was highlighted in this study. Significantly, the main environmental implications of this study are as follows: (1) lake eutrophication of phytoplankton OM accelerated the burial of PAHs in lake sediment; (2) economic development models and energy structure significantly influence the sedimentary PAHs. This study highlights the coupling relationship between OM burial and PAHs sedimentation, and the importance of accelerating the transformation of economic energy structure.


Assuntos
Lagos , Hidrocarbonetos Policíclicos Aromáticos , Biomassa , China , Carvão Mineral , Fitoplâncton
5.
Nanomaterials (Basel) ; 13(18)2023 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-37764571

RESUMO

The design of non-buckling interconnects with thick sections has gained important applications in stretchable inorganic electronics due to their simultaneous achievement of high stretchability, low resistance, and low heat generation. However, at the same time, such a design sharply increased the tensile stiffness, which is detrimental to the conformal fit and skin comfort. Introducing the fractal design into the non-buckling interconnects is a promising approach to greatly reduce the tensile stiffness while maintaining other excellent performances. Here, a hierarchical theory is proposed for the tensile stiffness of the non-buckling fractal-inspired interconnects with an arbitrary shape at each order, which is verified by the finite element analysis. The results show that the tensile stiffness of the non-buckling fractal-inspired interconnects decreases with the increase in either the height/span ratio or the number of fractal orders but is not highly correlated with the ratio of the two adjacent dimensions. When the ratio of the two adjacent dimensions and height/span ratio are fixed, the tensile stiffness of the serpentine fractal-inspired interconnect is smaller than that of sinusoidal and zigzag fractal-inspired interconnects. These findings are of great significance for the design of non-buckling fractal-inspired interconnects of stretchable inorganic electronics.

6.
Adv Mater ; 35(28): e2300340, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37022130

RESUMO

Achieving or enhancing the elastic stretchability of inorganic stretchable electronics is critically significant. However, only two types of fundamental strategies-using the prestrained elastic substrate and designing the geometric layouts-are exploited thus far. This study proposes a third strategy, an overstretch strategy, applied beyond the designed elastic range of stretchable structures after transfer printing and bonding to a soft substrate. The theoretical, numerical, and experimental results collectively prove that the overstretch strategy can double the designed elastic stretchability of fabricated stretchable electronics and is valid for various geometrical interconnects with both thick and thin cross-sections. The underlying mechanism is that the elastic range of the critical part of the stretchable structure is doubled, owing to the evolution of the elastoplastic constitutive relation during overstretching. The overstretch strategy can be easily executed and combined with the other two strategies to enhance elastic stretchability, which has profound implications for the design, fabrication, and applications of inorganic stretchable electronics.


Assuntos
Eletrônica , Impressão
7.
Environ Pollut ; 307: 119500, 2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-35667519

RESUMO

Microplastics (MPs) pollution in Tangxun Lake, the largest urban lake in China, was investigated. The average MPs pollution in sediment (1.81 ± 1.75 × 104 items kg-1) is at a high level, while the MPs in lakeshore water (917.77 ± 742.17 items m-3) is in the middle to low level compared with existing studies, which is related to the government's protection. Fragments and fibers are the most common shapes in sediment and water, respectively. MPs size <1 mm dominates in the sediment, while the MPs in water has a larger size. The distribution of MPs in the inner lake shows that pellets tend to "hidden" in sediments. Suspected MPs are randomly selected for polymer detection by Micro-Raman microscopy. Polypropylene (PP), polyethylene (PE) and polyethylene terephthalate (PET) are the most common polymer types in water, sediment and atmospheric deposition MPs samples. The input of wastewater, fishery and surrounding human activities are the main sources of MPs in sediment. Atmospheric deposition has a great impact on the distribution of MPs, while the contribution of surface runoff to lake MPs is not remarkable. In addition, MPs in sediments have exceeded the environmental carrying capacity. More attention should be focused on the sediment, where huge amounts of MPs are "hidden".


Assuntos
Microplásticos , Poluentes Químicos da Água , China , Monitoramento Ambiental , Sedimentos Geológicos , Humanos , Lagos/análise , Plásticos , Águas Residuárias , Água , Poluentes Químicos da Água/análise
8.
ACS Nano ; 16(4): 5961-5974, 2022 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-35363481

RESUMO

We introduce a stretchable electronic facial mask (SEFM) as a platform for facial healthcare, which can integrate with various sensors and actuators. As a demonstration, an SEFM for sonophoresis enabling the promotion of the delivery effect of a drug mask is developed. To overcome the technique challenges, several approaches including the design of the joined silicone layer by two planar half-face portions and the single-side soft pressing (SSSP) technique for encapsulation are exploited in this work, which could be extended to the design and fabrication of other stretchable electronics. The mechanical, thermal, electrical, and ultrasonic characteristics of the SEFM are all verified by the finite element analysis and experiments. Finally, we prove the effect of the SEFM on accelerating the delivery of hyaluronic acid (HA) through animal experiments and confirm that the SEFM can enhance the skin moisture content by 20% via human facial experiments.


Assuntos
Dispositivos Eletrônicos Vestíveis , Animais , Humanos , Máscaras , Eletrônica , Pele
9.
Environ Pollut ; 303: 119173, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35306093

RESUMO

The global pollution of microplastics (MPs) has attracted widespread attention, and the atmosphere was an indispensable media for the global transmission of MPs. With the growing awareness of MPs, atmospheric microplastics (AMPs) have been proposed as a new topic in recent years. Compared with the extensive studies on MPs in Marine and terrestrial environments, the studies of AMPs remain limited. In this study, sampling and analysis methods, occurrence, source analysis and health risk of AMPs were summarized and discussed. According to the different sampling methods, AMPs can be divided into suspension microplastics (SAMPs) and deposition microplastics (DAMPs). Previous studies have shown that SAMPs and DAMPs differ in composition and abundance, with SAMPs generally having a higher fraction of fragments. The mechanism of the migration of AMPs between different media was not clear yet. We further collated global data on the composition characteristics of MPs in soil and fresh water, which showed that the fragment MPs in soil and fresh water was higher than that in the atmosphere. Polymers in soil and fresh water were mainly PP and PE, while AMPs in the atmosphere were mainly PET. The shape composition of the MPs in both atmospheric and freshwater systems suggests that there may be the same dominant factor. The transport of AMPs and source apportionment were the important issues of current research, but both of them were at the initial stage. Therefore, AMPs needs to be further studied, especially for the source and fate, which would be conducive to understand the global distribution of AMPs. Furthermore, a standardized manual on sampling and processing of AMPs was also necessary to facilitate the comparative analysis of data between different studies and the construction of global models.


Assuntos
Microplásticos , Poluentes Químicos da Água , Meios de Cultura , Monitoramento Ambiental , Plásticos , Solo , Poluentes Químicos da Água/análise
10.
Huan Jing Ke Xue ; 43(2): 619-628, 2022 Feb 08.
Artigo em Chinês | MEDLINE | ID: mdl-35075836

RESUMO

In order to investigate the pollution characteristics and sources of water-soluble ions in atmospheric PM2.5 in different regions of central China during summer, Wuhan, Suizhou, and Pingdingshan were selected as urban, suburban, and rural monitoring stations, respectively, to collect PM2.5 samples, and the mass concentration of PM2.5 in the atmosphere and the contents of eight water-soluble ions were analyzed. The results showed that ρ(water-soluble ions) at the three sites showed obvious spatial distribution characteristics, with Pingdingshan[(36.29±9.82) µg·m-3] > Wuhan[(32.55±10.05) µg·m-3] > Suizhou[(26.10±6.23) µg·m-3], accounting for 52.47%, 51.32%, and 48.61% of the PM2.5 mass concentration, respectively. In the Pingdingshan station, the proportion of water-soluble ions was the largest due to biomass combustion in the rural area. Additionally, SNA (SO42-, NO3-, and NH4+) were the main ionic components, accounting for 95.65%, 96.12%, and 97.33% of the total water-soluble ions, respectively. The mean values of SOR of the Wuhan (0.64) and Suizhou (0.63) stations were higher than that of the Pingdingshan station (0.50), whereas the NOR values of the Wuhan (0.18) and Pingdingshan (0.19) stations were higher than that of the Suizhou station (0.15). The difference in SOR and NOR among stations was affected by the secondary conversion mechanism, the ammonia-rich environment, and the surrounding traffic sources, respectively. The PM2.5 at the Wuhan and Pingdingshan stations was in general alkaline, whereas at the Suizhou station it was neutral or weakly acidic, which was mainly caused by differences in NH4+. NH4+ mainly existed in the form of (NH4)2SO4 and NH4NO3 at the Wuhan and Pingdingshan stations, whereas at the Suizhou station it mainly existed in the form of (NH4)2SO4 or (NH4)HSO4. PCA-MLR analysis revealed that the Wuhan (89.27%) and Suizhou (67.38%) stations were the most affected by secondary conversion sources, whereas the Wuhan station was also affected by industrial sources (8.54%) and coal sources (2.27%). The pollution sources of the Suizhou station also included biomass combustion (24.42%) and dust sources (8.25%). The Pingdingshan station was most affected by biomass combustion (58.37%), followed by dust and combustion sources (38.05%) and traffic sources (3.58%). The analysis of potential sources of SNA (PSCF) showed that the main potential source areas of Wuhan were the boundary of Hubei, Henan, and Anhui and the southwest area of Anhui. Suizhou and Pingdingshan were affected by long-distance transport, and the main potential source regions were distributed in Shanghai, Jiangsu, and Anhui provinces from the east coast to the west.


Assuntos
Poluentes Atmosféricos , Material Particulado , Aerossóis/análise , Poluentes Atmosféricos/análise , China , Monitoramento Ambiental , Tamanho da Partícula , Material Particulado/análise , Estações do Ano , Água
11.
Huan Jing Ke Xue ; 43(2): 859-866, 2022 Feb 08.
Artigo em Chinês | MEDLINE | ID: mdl-35075859

RESUMO

In order to understand the pollution characteristics, spatial distribution, potential sources, and ecological risk of heavy metals in the sediments of Tangxun Lake, the contents of heavy metals (As, Hg, Cd, Cr, Cu, Pb, Zn, and Ni) in the surface sediments of Tangxun Lake were analyzed, and the pollution status and potential ecological risk degree of heavy metals in the sediments were evaluated using the geo-accumulation index and potential ecological risk index. The potential sources of heavy metal pollutants were analyzed by correlation and principal component analysis. The results showed that except for Cr, the contents of other heavy metals were higher than their background values. The contents of Hg, Cd, Zn, and Cu were higher in the southwest and northeast corners of the lake, which may come from the combined pollution of sewage discharge, fisheries, and surrounding industrial and agricultural activities. The geo-accumulation index and potential ecological risk showed that Hg and Cd were in moderate pollution; Cu, Pb, and Zn were in non-light pollution; and As, Cr, and Ni were in non-pollution. Except for Hg and Cd, there were serious and serious potential ecological risks, and the other elements were at a low risk level. The heavy metals in the surface sediments of Tangxun Lake showed a high ecological risk level.


Assuntos
Metais Pesados , Poluentes Químicos da Água , China , Monitoramento Ambiental , Sedimentos Geológicos , Lagos , Metais Pesados/análise , Medição de Risco , Poluentes Químicos da Água/análise
12.
ACS Nano ; 16(1): 541-553, 2022 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-34919398

RESUMO

Most of the existing stretchable strain sensors are based on the contact-resistance mechanism, where the stretchability and resistance variation depend on the change of the contact relationship of the conductive microstructures. These sensors usually exhibit large sensing ranges and gauge factors but unsatisfactory repeatability and linearity of the electrical responses because the contact is unstable. Here, we report a completely different design for stretchable strain sensors based on a contact-resistance-free structure, i.e., the off-axis serpentine sandwich structure (OASSS), with the mechanism of the stretch-bending-stretch transformation (SBST). Neither unstable contact resistance nor nonlinear constitutive and geometric behaviors occur for the OASSS while the sensor undergoes a large applied strain (50%), which guarantees high repeatability (repeatability error = 1.58%) and linearity (goodness-of-fit >0.999). Owing to such performances, the present sensors are not only applied to monitoring human activities and medical surgery but also to the ground tests of Tianwen-1, China's first Mars exploration mission.


Assuntos
Dispositivos Eletrônicos Vestíveis , Humanos , Condutividade Elétrica
13.
Nat Commun ; 12(1): 7038, 2021 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-34857751

RESUMO

Organic semiconducting polymers have opened a new paradigm for soft electronics due to their intrinsic flexibility and solution processibility. However, the contradiction between the mechanical stretchability and electronic performances restricts the implementation of high-mobility polymers with rigid molecular backbone in deformable devices. Here, we report the realization of high mobility and stretchability on curvilinear polymer microstructures fabricated by capillary-gradient assembly method. Curvilinear polymer microstructure arrays are fabricated with highly ordered molecular packing, controllable pattern, and wafer-scale homogeneity, leading to hole mobilities of 4.3 and 2.6 cm2 V-1 s-1 under zero and 100% strain, respectively. Fully stretchable field-effect transistors and logic circuits can be integrated in solution process. Long-range homogeneity is demonstrated with the narrow distribution of height, width, mobility, on-off ratio and threshold voltage across a four-inch wafer. This solution-assembly method provides a platform for wafer-scale and reproducible integration of high-performance soft electronic devices and circuits based on organic semiconductors.

14.
Huan Jing Ke Xue ; 42(11): 5122-5130, 2021 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-34708951

RESUMO

In recent years, frequent haze episodes have resulted in the deterioration of air quality of the Fenwei Plain during winter and holidays. Besides coal combustion and industrial emissions, the topography and climate of the Fenwei Plain were also the main causes of the haze. The samples were collected in Linfen of Fenwei Plain during the Spring Festival from February 2 to February 13, 2019. The 13 elements(Li, Be, Ti, Rb, Sc, Y, La, Ce, Zr, V, Tl, U, and Sn) in PM2.5 were determined by inductively coupled plasma mass spectrometry(ICP-MS). Combined with the meteorological data, the spatial and temporal distribution of pollutants and potential source analysis were evaluated by cluster analysis and backward trajectory. The average concentration of SO2 was 58.39 µg·m-3 during the sampling period, which exceeded the 24 h average mass concentration limit(50.00 µg·m-3) of national ambient air quality standard(GB 3095-2012). The average concentrations of O3, NO2, and CO was 52.15 µg·m-3, 29.02 µg·m-3, and 2.29 mg·m-3, respectively. The results showed that SO2 was the dominated pollutant. NO2 and CO were mainly affected by diffusion from urban areas. The backward trajectory analysis indicated that the basin topography of the Fenwei Plain may be the main cause of the haze. The analysis of potential source contribution function(PSCF) of soil sources showed that the potential dominated areas included Northern Shaanxi, southern Gansu and Southern Ningxia., which were mainly affected by the monsoon climate.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Atmosféricos/análise , Poluição do Ar/análise , China , Monitoramento Ambiental , Férias e Feriados , Material Particulado/análise , Estações do Ano
15.
Environ Pollut ; 291: 118173, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34537600

RESUMO

The sedimentary history of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) over the past 140 years in a lake sediment core from Huixian karst wetland was reconstructed. The total PAHs and OCPs concentrations ranged from 40.0 to 210 ng g-1 and 0.98 to 31.4 ng g-1, respectively. The vertical distribution of PAHs and OCPs in different stages was great consistent with the history of regional socio-economic development and the usage of OCPs. As the indicators of socio-economic development, gross domestic product (GDP), population, energy consumption, highway mileage, and private vehicles correlated with the PAHs concentrations, indicating the impact of human activities on PAHs levels. The PAHs and OCPs concentrations were also affected by environmental changes in the wetland, as reconstructed by total organic carbon (TOC), sand, silt, clay, quartz, and calcite in sediments. Redundancy analysis (RDA) results showed TOC was the dominant factor to explain the concentrations of PAHs and OCPs with the explanation of 86.7% and 43.5%, respectively. In addition, TOC content had significantly positive correlation with PAHs (0.96, p < 0.01) and OCPs (0.78, p < 0.01). In particular, the significantly positive correlation (p < 0.05) between calcite and PAHs and OCPs inferred that karstification might play an important role in the migration of PAHs and OCPs in the karst area. Therefore, the lake in Huixian wetland tended to be a sink more than a source of PAHs and OCPs influenced by the increasing TOC content and karstification under climate warming.


Assuntos
Hidrocarbonetos Clorados , Praguicidas , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , China , Monitoramento Ambiental , Sedimentos Geológicos , Atividades Humanas , Humanos , Hidrocarbonetos Clorados/análise , Lagos , Praguicidas/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise , Áreas Alagadas
16.
Huan Jing Ke Xue ; 42(10): 4593-4601, 2021 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-34581101

RESUMO

To explore the pollution characteristics and potential health risks of heavy metals in PM2.5 on haze days in Central China, PM2.5 samples were collected from the Huanggang monitoring station, a regional observation point in Central China, between January 13 and 24, 2018. The contents of Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Sn, and Pb in PM2.5 were analyzed by inductively coupled plasma mass spectrometry(ICP-MS), and the enrichment factor method was used to determine the potential risk based on the exposure model recommended by the Environmental Protection Administration(EPA). The results showed that during the observation period, the concentrations of Zn in PM2.5 were highest, and the concentrations of the carcinogens As and Cd were higher than the secondary standard limits of China's ambient air quality standard(GB 3095-2012), with 70% of these elemental concentrations accounting for the largest proportion in the middle haze period. The enrichment factor analysis showed that Cd, Sn, Co, Pb, and Zn were the most abundant elements, especially during the middle haze period, and were mostly derived from transportation and coal combustion. The results of the human health risk assessment showed that exposure via hand-mouth feeding was the main non-carcinogenic risk, and the exposure and non-carcinogenic risks of children were significantly higher than those of adults. Pb poses a non-carcinogenic risk to children, while heavy metals in PM2.5 pose no non-carcinogenic risks to adults and carcinogenic heavy metals pose no carcinogenic risks.


Assuntos
Metais Pesados , Material Particulado , Adulto , Criança , China , Monitoramento Ambiental , Humanos , Metais Pesados/análise , Material Particulado/análise , Medição de Risco
17.
Environ Sci Pollut Res Int ; 28(40): 56234-56246, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34046838

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) are a kind of organic pollutants with carcinogenic, teratogenic, and mutagenic effects. This study aims to assess the effects of changes in China's socio-economic indicators represented by energy consumption and number of motor vehicles, on PAHs and black carbon (BC) deposition. For this, a 50-cm peat core from Dajiuhu peatland, Central China, was collected and divided into 50 subsamples to establish a sedimentary record of about 200 years with radioactive 210Pb. The Σ16PAH concentration ranged from 212.67 to 830.10 ng·g-1, mainly composed of 2- and 3-ring PAHs, and BC ranged from 7.89 to 36.48%. The deposition characteristics of BC first increased and then decreased from the core bottom to the top. The predominant of the carcinogenic PAHs (C-PAHs) was Dibenzo[a,h]anthracene (DBA) before 1949, and then changed to Benzo[b]fluoranthene (BbF). Ratio of Fla/Pyr, (3+4)-ring/(5+6)-ring PAHs, and BaA/(BaA+Chr), IcdP/(IcdP+BghiP) suggested that long-range atmospheric transmission (LRAT) and pyrogenic were the main PAHs sources, but that local PAH emission contribution gradually increased since 1990, and mixed (petroleum and combustion) sources were the dominant since 2000. The high concentration of Phenanthrene (Phe) and Naphthalene (Nap) were likely from plant product. Furthermore, increased concentrations of 4-, 5-, and 6-ring PAHs showed significant correlations with increased coal and petroleum consumption and the number of motor vehicles, respectively, and this influence has strengthened after 2000. These were caused by rapid urbanization and industrialization following the implementation of the reform and opening up policy in 1978, and a new round of urbanization after 2000.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Carbono , Monitoramento Ambiental , Atividades Humanas , Humanos , Hidrocarbonetos Policíclicos Aromáticos/análise , Solo
18.
ACS Nano ; 14(3): 3442-3450, 2020 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-32149493

RESUMO

Wearable and stretchable electronics including various conductors and sensors are featured with their lightweight, high flexibility, and easy integration into functional devices or textiles. However, most flexible electronic materials are still unsatisfactory due to their poor recoverability under large strain. Herein, we fabricated a carbon nanotubes (CNTs) and polyurethane (PU) nanofibers composite helical yarn with electrical conductivity, ultrastretchability, and high stretch sensitivity. The synergy of elastic PU molecules and spring-like microgeometry enable the helical yarn excellent stretchability, while CNTs are stably winding-locked into the yarn through a simple twisting strategy, making good conductivity. By virtue of the interlaced conductive network of CNTs in microlevel and the helical structure in macrolevel, the CNTs/PU helical yarn achieves good recoverability within 900% and maximum tensile elongation up to 1700%. With these features, it can be used as a superelastic and highly stable conductive wire. Moreover, it also can monitor the human motion as a rapid-response strain sensor by adjusting the content of the CNTs simply. This general and low-cost strategy is of great promise for ultrastretchable wearable electronics and multifunctional devices.

19.
Nat Commun ; 10(1): 3912, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31477721

RESUMO

Fabricating ultrathin organic semiconductor nanostructures attracts wide attention towards integrated electronic and optoelectronic applications. However, the fabrication of ultrathin organic nanostructures with precise alignment, tunable morphology and high crystallinity for device integration remains challenging. Herein, an assembly technique for fabricating ultrathin organic single-crystal arrays with different sizes and shapes is achieved by confining the crystallization process in a sub-hundred nanometer space. The confined crystallization is realized by controlling the deformation of the elastic topographical templates with tunable applied pressures, which produces organic nanostructures with ordered crystallographic orientation and controllable thickness from less than 10 nm to ca. 1 µm. The generality is verified for patterning various typical solution-processable materials with long-range order and pure orientation, including organic small molecules, polymers, metal-halide perovskites and nanoparticles. It is anticipated that this technique with controlling the crystallization kinetics by the governable confined space could facilitate the electronic integration of organic semiconductors.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...