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1.
Sci Rep ; 13(1): 16360, 2023 09 29.
Artículo en Inglés | MEDLINE | ID: mdl-37773428

RESUMEN

As one of the key, long-term occupied sites in the Southern Levant, Jericho was one of the most important early Neolithic centres to witness social and economic changes associated with the domestication of plants and animals. This study applies strontium (87Sr/86Sr), oxygen (δ18O) and carbon (δ13C) isotope analyses to the enamel of 52 human teeth from Pre-Pottery Neolithic (PPN) layers of Jericho to directly study human diet and mobility and investigate the degree of consolidation and the flexibility of social organization of Jericho society in the PPN period. The results indicate only two non-local individuals out of the 44 sampled inhabitants identified by strontium isotope analysis and are consistent with the presence of a largely sedentary community at PPN Jericho with no evidence for large-scale migration. We also construct strontium spatial baselines (87Sr/86Sr map) with local 87Sr/86Sr signatures for the sites across the Southern Levant based on systematic compilation and analysis of available data. In addition, we apply proteomic analysis of sex-specific amelogenin peptides in tooth enamel for sex estimation of the sampled individuals (n = 44), the results of which showed a sex-biased ratio (more male than female detected in this sample pool) in Jericho society during the PPN period, which may be due to the limited sample size or selective ritual practices like particular burial zones used for specific groups. We also pretreated a batch of human bone samples recovered from PPNB Jericho for stable carbon and nitrogen isotope analyses for dietary investigations. However, the extracted collagen showed poor preservation and no valid δ13C or δ15N data were obtained.


Asunto(s)
Proteómica , Diente , Humanos , Masculino , Animales , Femenino , Diente/química , Isótopos de Estroncio/análisis , Entierro , Carbono
2.
Sci Total Environ ; 904: 166895, 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-37683856

RESUMEN

The smart membrane with under-liquid dual superlyophobicity, which can achieve on-demand separation of oil/water emulsions only by simple liquid pre-wetting, is of essential value for the treatment of complicated real oil/water systems. Here, we first fabricated a stable suspension of imine-linked covalent organic framework nanospheres (TPB-DMTP-COF), and subsequently fabricated COF functionalized smart membranes with under-liquid dual superlyophobicity by immersing polyacrylonitrile-based (PAN-based) membranes into TPB-DMTP-COF nanosphere suspension. Accordingly, effective switchable separation of both oil-in-water and water-in-oil emulsions by TPB-DMTP-COF/PAN membranes can be achieved by employing pre-wetting processes (both the oil contact angle under water and the water contact angle under oil are over 150°). Specifically, the separation flux and the separation efficiency are higher than 1200 L/m2‧h and 98.0 %, and 2100 L/m2‧h and 97.4 % for the surfactant-stabilized oil-in-water and water-in-oil emulsions, respectively. Furthermore, the ultralow adhesions in liquid contributed to the outstanding reusability and antifouling resistance of the prepared TPB-DMTP-COF/PAN membranes. This work provides a feasible approach for fabricating a smart membrane with under-liquid dual superlyophobicity for oily wastewater treatment.

3.
Sensors (Basel) ; 22(19)2022 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-36236205

RESUMEN

A partitionable adaptive multilayer diffractive optical neural network is constructed to address setup issues in multilayer diffractive optical neural network systems and the difficulty of flexibly changing the number of layers and input data size. When the diffractive devices are partitioned properly, a multilayer diffractive optical neural network can be constructed quickly and flexibly without readjusting the optical path, and the number of optical devices, which increases linearly with the number of network layers, can be avoided while preventing the energy loss during propagation where the beam energy decays exponentially with the number of layers. This architecture can be extended to construct distinct optical neural networks for different diffraction devices in various spectral bands. The accuracy values of 89.1% and 81.0% are experimentally evaluated for MNIST database and MNIST fashion database and show that the classification performance of the proposed optical neural network reaches state-of-the-art levels.


Asunto(s)
Algoritmos , Redes Neurales de la Computación , Bases de Datos Factuales
4.
RSC Adv ; 12(28): 17990-18003, 2022 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-35765334

RESUMEN

The widespread use of graphene as a next-generation material in various applications requires developing an environmentally friendly and efficient method for fabricating functionalized graphene. Chemically, graphene can be used as an electron donor or attractor. Here, graphite was successfully exfoliated, and an in situ Diels-Alder reaction (D-A) was carried out to fabricate functionalized graphene with sole functional groups via mechanochemical ball milling. The reactivities of graphene acting as a diene or a dienophile were investigated. Few-layer (≤2 layers) graphene specimens were obtained by wet ball milling, heating in a nitrogen atmosphere, and solvent ultrasonic treatment. The ball-milling method was more effective than heating in a nitrogen atmosphere, and the [2 + 4] D-A of graphene was more dominant than the [4 + 2] D-A in the ball-milling process. The surface tension of functionalized graphene decreased, which provided a theoretical basis for the dispersion and exfoliation of graphite in a suitable solvent. Functionalized graphene still had a high electrical conductivity, which has far-reaching significance for functionalized graphene to be applied in electronic semiconductors and related applications. Meanwhile, functionalized graphene was applied to polymer composite fibers, the tensile strength and the Young's modulus could reach 780 MPa and 19 GPa. The volume resistivity was two orders of magnitude lower than that of pure fiber. Thus, the use of ball milling to efficiently exfoliate and in situ functionalize graphite will help to develop a strategy that can be widely used to manufacture nanomaterials for various application fields.

5.
RSC Adv ; 12(20): 12507-12516, 2022 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-35480377

RESUMEN

Shear thickening fluid (STF) is investigated to strength soft armor; however, its impact resistance still does not meet practical needs. In this work, a small amount of hydroxylated fullerene (C60) was mixed with STF to improve the thickening ratio. First, furfuryl alcohol (FA) was grafted onto C60 through a Diels-Alder (D-A) reaction to improve the dispersity of C60 in the STF. Sheath-core composite fibers (polyketone (PK) as the sheath and STF as the core) were then fabricated by coaxial electrospinning. Finally, composite fibers containing STF and C60 were wrapped on the surface of aramid yarns to fabricate a core-spun yarn. Under impact, these core-spun yarns manifested the characteristics of aramid fibers and the thickening advantages of the STF, solving problems of the hygroscopicity, migration, and leakage of STF. In addition, the content of STF was also greatly increased. The spike punching resistance of the core-spun yarn fabric is about 2.8 times that of the aramid fabric (AF) under the same area density. Impact-resistant core-spun yarn fabrics could provide a new direction for the development of soft armor.

6.
Carbohydr Polym ; 273: 118629, 2021 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-34561020

RESUMEN

In this paper, chitosan-based polyurethane (c-PU) microencapsulated phase change materials (MicroPCMs) were prepared via the interfacial polymerization reaction of hexamethylene diisocyanate and chitosan accompanied by the charge attraction-assisted. The utilization of natural non-toxic chitosan in MicroPCMs expanded the application of chitosan and guided a new approach to preparing green shell. And the morphology of MicroPCMs with different reaction ration, surfactant and the pH value of reaction system were systematically investigated. The MicroPCMs with c-PU shell exhibited outstanding latent thermal performance (ΔHm = 106.3 J/g, ΔHc = -105.1 J/g), high energy storage efficiency (E = 71.4%), excellent thermal stability and cyclic durability. The c-PU MicroPCMs with reversible photochromic show promising application in the fields of anti-counterfeiting technology and flexible wearable UV protective clothing.

7.
ACS Appl Mater Interfaces ; 13(35): 41657-41668, 2021 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-34432426

RESUMEN

Triboelectric nanogenerators (TENGs) are newly developed energy-harvesting mechanisms, which can efficiently transmute irregular mechanical energy into scarce electrical energy. However, the electrical performance of TENGs shows a decreasing tendency with the increase in temperature, and the negative effect caused by friction heat and operating environmental thermal stresses for the output performance, durability, and reliability are still a bottleneck, restricting the practical application of TENG electronic devices. Especially for wearable TENG devices, the heat-induced temperature rise evokes extreme discomfort and even hazards to human health. To effectively suppress the thermal negative effect and maintain the high-temperature steady electrical performance of TENGs, a novel thermo-regulating TENG (Tr-TENG) based on phase change materials (PCMs) is designed. The results state clearly that the Tr-TENG can maintain steady output performance without deterioration by the introduction of PCMs, during continuous heating and natural cooling, while the output performance of conventional TENG is decayed by 18.33%. More importantly, the Tr-TENG possesses high-efficiency thermal management ability, resulting in its improved durability, reliability, and thermal comfort. This study creates new possibilities for the development of advanced multifunctional TENGs with attractive characteristics and desirable performances and promotes the application of TENG electronic devices in harsh environments.

8.
Langmuir ; 37(31): 9415-9428, 2021 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-34310152

RESUMEN

The elimination of dye pollutants from wastewater is a significant concern that has prompted extensive research into the development of highly efficient photocatalytic membranes. A novel method was proposed to prepare photocatalysis-enhanced poly(acrylonitrile-methyl acrylate) (PAN-based) membranes in this study. In detail, the blended membrane containing SiO2@TiO2 nanoparticles with a shell-core structure was first prepared via thermal-induced phase separation. The SiO2 nanoshells were dissolved, and the released TiO2 nanoparticles migrated to the membrane surface during a simple hydrolysis process, which prevents the TiO2 nanoparticles from directly contacting or interacting with the polymer matrix. The hydrogen bonds bind the exposed TiO2 with the PAN membrane surface, resulting in the formation of the TiO2@HPAN hybrid membrane. The photocatalytic efficiency of the TiO2@HPAN membrane doubled compared with that of nonhydrolyzed membranes. In the presence of UV light, the hybrid membrane can degrade 99.8% of methylene blue solution in less than 2 h, compared to only 86.1% for the blended membranes. Further, the TiO2@HPAN membrane showed excellent photocatalytic activity for cationic dyes due to electrostatic attraction. Moreover, the high-flux recovery rate and recycling stability of the TiO2@HPAN membrane lead to an excellent antifouling property. The facile preparation method proposed in this work shows extraordinary potential for the development of highly efficient selective photocatalytic materials for cationic dyes to be used in wastewater treatment applications.

9.
Toxicol Res (Camb) ; 10(1): 60-67, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33613973

RESUMEN

BACKGROUND: Nanoparticulate titanium dioxide (Nano-TiO2) has been widely used in food industry, and it has been demonstrated to have adverse effects on mice and human stomach, but its mechanism is rarely concerned. The aim of this study is to determine the effects of nano-TiO2 on the stomach and confirm the role of oxidative stress and apoptosis in the mice gastric damage caused by nano-TiO2, as well as its molecular mechanisms. METHODS: Mice were continuously exposed to nano-TiO2 with 1.25, 2.5 and 5 mg/kg bw by intragastric administration for 9 months in the present study. The ultrastructure, levels of reactive oxygen species (ROS) and peroxides, activities of antioxidant enzymes and mitochondria-related enzymes, ATP contents as well as apoptosis-related factors expression in mice stomach were examined. RESULTS: Oxidative stress, apoptosis and nano-TiO2 aggregation were found in gastric mucosal smooth muscle cells after nano-TiO2 exposure. Nano-TiO2 exposure also resulted in the over-production of ROS and peroxides, decrease of ATP production and activities of antioxidant enzymes and mitochondria-related ATPases, upregulation of apoptosis-related factors including γH2AX, Cyt c, caspase 3, and p-JNK expression, and down-regulation of Bcl-2 expression in mice stomach. CONCLUSIONS: The gastric toxicity of mice induced by chronic exposure to low dose nano-TiO2 may be associated with oxidative stress and mitochondria-mediated apoptosis in mice.

10.
Environ Toxicol ; 36(3): 408-416, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33098623

RESUMEN

China is the world's largest rare earth producer and exporter, previous studies have shown that rare earth elements can cause oxidative damage in animal testis. However, the molecular mechanisms underlying these observations have yet to be elucidated. In this paper, male mice were fed with different doses (10, 20, and 40 mg/kg BW) of LaCl3 for 90 consecutive days, regulatory role of nuclear factor erythroid-2 related factor 2 (Nrf-2)/antioxidant response element (ARE) pathway in testicular oxidative stress induced by LaCl3 were investigated. Analysis showed that LaCl3 exposure could lead to severe testicular pathological changes and apoptosis in spermatogenic cells, it up-regulated the peroxidation of lipids, proteins and DNA, and induced the excessive levels of reactive oxygen species (ROS) production in mouse testis, reduced the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and glutathione S epoxide transferase (GST) as well as the glutathione (GSH) content. Furthermore, exposure to LaCl3 also downregulated the expression of Nrf2 and its target gene products, including heme oxygenase 1 (HO-1), glutamate-cysteine ligase catalytic subunit (GCLC), NAD(P)H dehydrogenase [quinine] 1(NQO1), protein kinase C (PKC), and phosphatidylinositol 3-kinase (PI3K), but upregulated the expression of Kelch-like ECH-related protein 1 (Keap1) in damaged mouse testes. Collectively, our data imply that the oxidative damage induced by LaCl3 in testis was related to inhibition of the Nrf-2/AREs pathway activation.


Asunto(s)
Lantano/toxicidad , Estrés Oxidativo/fisiología , Animales , Elementos de Respuesta Antioxidante , Apoptosis , Glutatión/metabolismo , Glutatión Peroxidasa/metabolismo , Hemo-Oxigenasa 1/metabolismo , Proteína 1 Asociada A ECH Tipo Kelch/metabolismo , Masculino , Ratones , Factor 2 Relacionado con NF-E2/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Testículo/metabolismo
11.
Appl Opt ; 59(33): 10441-10450, 2020 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-33361977

RESUMEN

The real-time processing of synthetic aperture radar (SAR) data has a high requirement for the processor, which is a difficult problem in SAR real-time processing. With the rapid development of optoelectronic devices, traditional electrical SAR data processing can be converted into optoelectronic processing to improve the processing speed. In this paper, a new type of optical device is proposed to improve the processing speed of SAR data. With the help of a spatial light modulator (SLM), the initial SAR signal and matched filter function are loaded on the input plane and spectrum plane of the 4f system, respectively. Using an optical lens with the function of the Fourier transform, the Fourier transform and inverse Fourier transform of the SAR signal are carried out to realize the fast imaging of SAR. In theory, the processing speed of SAR data is the speed of light. Compared with traditional methods such as the range-Doppler (RD) algorithm, it is no longer necessary to carry out a one-dimensional Fourier transform but to carry out matching filtering for the azimuth and range of the spectrum plane of 4f system at the same time. In this way, it is not necessary to introduce a cylindrical lens, only a spherical lens is needed to realize the Fourier transform imaging of SAR. Finally, a two-dimensional SAR processing optical system is built to obtain the SAR image in real time.

12.
Sensors (Basel) ; 20(16)2020 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-32781628

RESUMEN

To address the miniaturization of the spectral imaging system required by a mounted platform and to overcome the low luminous flux caused by current spectroscopic technology, we propose a method for the multichannel measurement of spectra using a broadband filter in this work. The broadband filter is placed in front of a lens, and the spectral absorption characteristics of the broadband filter are used to achieve the modulation of the incident spectrum of the detection target and to establish a mathematical model for the detection of the target. The spectral and spatial information of the target can be obtained by acquiring data using a push-broom method and reconstructing the spectrum using the GCV-based Tikhonov regularization algorithm. In this work, we compare the accuracy of the reconstructed spectra using the least-squares method and the Tikhonov algorithm based on the L-curve. The effect of errors in the spectral modulation function on the accuracy of the reconstructed spectra is analyzed. We also analyze the effect of the number of overdetermined equations on the accuracy of the reconstructed spectra and consider the effect of detector noise on the spectral recovery. A comparison between the known data cubes and our simulation results shows that the spectral image quality based on broadband filter reduction is better, which validates the feasibility of the method. The proposed method of combining broadband filter-based spectroscopy with a panchromatic imaging process for measurement modulation rather than spectroscopic modulation provides a new approach to spectral imaging.

13.
Sensors (Basel) ; 20(11)2020 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-32486498

RESUMEN

How to perform imaging beyond the diffraction limit has always been an essential subject for the research of optical systems. One effective way to achieve this purpose is Fourier ptychography, which has been widely used in microscopic imaging. However, microscopic imaging measurement technology cannot be directly extended to imaging macro objects at long distances. In this paper, a reconstruction algorithm is proposed to solve the need for oversampling low-resolution images, and it is successfully applied to macroscopic imaging. Compared with the traditional FP technology, the proposed sub-sampling method can significantly reduce the number of iterations in reconstruction. Experiments prove that the proposed method can reconstruct low-resolution images captured by the camera and achieve high-resolution imaging of long-range macroscopic objects.

14.
RSC Adv ; 10(56): 33965-33971, 2020 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-35519064

RESUMEN

Light-weight, mechanically flexible, transparent thermoelectric devices are promising as portable, and easy-to-integrate energy sources. Poly(3,4-ethylenedioxythiophene) nanowires (PEDOT NWs) possessing high electrical conductivity were synthesized by a facile self-assembled micellar soft-template method. And then, Te nanowires (Te NWs) with high Seebeck coefficient were easily synthesized by the solution process and then added as an inorganic filler to form the PEDOT NW/Te NW nanocomposite films via a simple and convenient vacuum filtration method. The thermoelectric (TE) properties of the nanocomposites were characterized in this research. A maximum power factor of 58.03 µW m-1 K-2 is obtained from the film containing 90 wt% Te NWs at room temperature, which is dozens of times that of the pure PEDOT NW film. This work uses the as-prepared PEDOT NWs/Te NW (90 wt%) nanocomposite film to fabricate a flexible thermoelectric generator and an output voltage of 2.8 mV was generated at a temperature difference of 13.5 K between the environment and human body.

15.
J Nanosci Nanotechnol ; 20(3): 1685-1696, 2020 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-31492331

RESUMEN

The process in which the nanofiber membrane is used to remove heavy metal ions and separation of oil-water solution is analyzed. Herein, smooth structures are induced by rGO-g-PAO sheets, which could be attributed to the strong interaction between P(AN-MA) and rGO-g-PAO. It is rewarding to note that the P(AN-MA)/rGO-g-PAO nanofiber membrane would exhibit superhydrophilic traits in the air and ultra-low oil-adhesive traits underwater when the concentration of P(AN-MA) and PAO is 13 wt.% and 0.3 wt.%, respectively. The amidoxime (-C(NH2) NOH) groups on the membrane surface can efficiently adsorb copper (Cu(II)) (1.65 mmol/g) and chromium (Cr(VI)) (4.70 mmol/g) ions in the waste water. Meanwhile, the P(AN-MA)/rGO-g-PAO nanofiber membrane exhibits ultrahigh flux (~6150 LMH), satisfying rejection rate (~97%) and outstanding flux recovery ratio (~99%) in separating oil water emulsion.

16.
ACS Appl Mater Interfaces ; 12(2): 2926-2934, 2020 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-31750647

RESUMEN

Covalent organic frameworks (COFs) have been widely used in catalysis, energy storage, environmental protection, and separation. However, they require a long assembly period (∼3 days) and complex synthesis conditions; differences in water resistance have restricted their overall versatility. In this paper, the preparation of COF-DhaTab was optimized, and this process can be easily performed in air. Thus, it is feasible for the scale-up of COF-DhaTab in the near future. The superhydrophobic properties of COF-DhaTab (water contact angle, >150°) can be created by regulating the wettability of COF-DhaTab by grafting fluoride. When the grafting degree of fluoride increased to 4.32%, the water contact angle of COFs increased from 0° to more than 150°. The grafted COFs are termed COF-DhaTab fluoride (COF-DTF). The chemically modified COF-DhaTab maintains its original porosity and crystallinity. The superhydrophobic COF-DTF can be applied to various substrates, for example, foam, fabric, and glass. These all exhibit outstanding water repellency, self-healing, and excellent self-cleaning. Importantly, the coating maintains its original superhydrophobicity even under extremely acidic/basic conditions (pH = 1-14) and toward boiling water (100 °C). Furthermore, COF-DTF displays long-term stability and is easily scaled. It is a promising and practical candidate for hydrophobic modifications to various substrates.

17.
Langmuir ; 35(50): 16545-16554, 2019 12 17.
Artículo en Inglés | MEDLINE | ID: mdl-31755726

RESUMEN

Covalent organic frameworks (COFs) have attracted broad interest in a number of fields including gas access, catalysis, and ionic adsorption. However, owing to the low stability in water, the application of COFs in the field of oil/water separation is extensively impeded. In this paper, we synthesized COF-DhaTab/polyacrylonitrile (PAN) nanofibrous composite membranes with a bioinspired spindle-knotted structure via a facile blending electrospinning method. The COF-DhaTab/PAN composite membrane shows prewetting-induced superoleophobicity under water and superhydrophobicity under oil. It possesses outstanding rejection ratio (>99.9%), excellent antifouling performance, and ultrahigh oil/water mixture flux up to 4229.29 L/m2h even though driven only by gravity. Specifically, an extraordinary oil contact angle under water (152.3°) and a satisfied water contact angle under oil (153.7°) were offered by the composite membrane. These are mainly attributed to the spindle-knotted structures induced by COFs. To the best of our knowledge, the application of COF/PAN composite membrane in the field of oil/water separation has never been reported. It is an innovative approach for oily wastewater treatment and oil purification.

18.
ACS Appl Mater Interfaces ; 11(50): 46920-46929, 2019 Dec 18.
Artículo en Inglés | MEDLINE | ID: mdl-31756069

RESUMEN

Due to the complexity of harmful wastewater components, environmental and multifunctional materials are required for sewage purification. In this paper, a novel kidney-bean-skin-like hydrophilic porous polyacrylonitrile/reduced graphene oxide-g-poly(amidoxime)-loaded Ag+ (H-PPAN/rGO-g-PAO@Ag+/Ag) composite nanofiber membrane was fabricated by combining electrospinning and hydrolysis methods. The spinning solution was pumped at a rate of 0.4 mL/h with the voltage set at a constant value of 23 kV. Then, some of the -CN groups switched to hydrophilic -COOH groups via a hydrolysis method, which acts as a linker of GO-g-PAN, Ag+, and the polyacrylonitrile (PAN) matrix. A further step of chelation and thermal treatment were used for generating Schottky junctions between rGO-g-PAO@Ag+ and Ag. After five-cycle tests, it exhibited outstanding mechanical properties ensuring the filtration and purification performance of the H-PPAN/rGO-g-PAO@Ag+/Ag composite nanofiber membrane (i.e., the tensile strength was still 7.21 MPa, and the elongation was 61.53%) for simulated wastewater. The methods of thermal treatment and high-pressure Hg lamp irradiation promoted the reduction of GO to rGO and Ag+ to Ag particles, which endows the final product H-PPAN/rGO-g-PAO@Ag+/Ag with excellent photocatalytic and bactericidal properties. Its catalytic efficiency for dyes benzoic acid (BA), Rhodamine B (RhB), methylene blue (MB), and methyl orange (MO) was up to 99.8, 98, 95, and 91%. The antibacterial rate was 100% against Escherichia coli and 99% against Staphylococcus aureus. More importantly, the photocatalytic and antibacterial PAN-based nanofiber membrane can be simply scaled up, which provides the membrane with great potential in highly efficient wastewater treatment and augmenting water supply.

19.
ACS Appl Mater Interfaces ; 11(49): 45832-45843, 2019 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-31738041

RESUMEN

The applications of phase change materials (PCMs) in some practical circumstances are currently limited due to the constant strong rigidity, poor thermal conductivity, and low photoabsorption property. Therefore, the design of flexibility-enhanced, highly efficient PCMs is greatly desirable and challenging. In this work, novel PCM composites (CPmG-x) with stable forms and thermally induced flexibility were successfully prepared by grafting the comblike poly(hexadecyl acrylate) polymer (PA16, phase change working substance) onto a cellulose support by atom transfer radical polymerization (ATRP). Modified graphene (GN16) was incorporated into the synthesized material to enhance its enthalpy, thermal conductivity, and physical strength. The prepared CPmG-x composites exhibit excellent softness and flexibility after phase transition of PA16. The addition of GN16 increases the thermal conductivity and enthalpy of CPmG-x materials to 1.32 W m-1 K-1 (9 wt % GN16) and 103 J g-1 (5 wt % GN16), respectively. Assessments of the solar-to-thermal energy conversion and storage efficiencies indicate that CPmG-x composites possess great potential for use in thermal energy management applications and solar energy collection systems.

20.
Nanomaterials (Basel) ; 9(12)2019 Nov 21.
Artículo en Inglés | MEDLINE | ID: mdl-31766336

RESUMEN

In this paper, the sodium salt of styrene-maleic anhydride copolymer (SMA) was used as a stabilizer in the process of graphite exfoliation to few-layer graphene using the technique of microfluidization in water. This method is simple, scalable, and cost-effective, and it produces graphene at concentrations as high as 0.522 mg mL-1. The generated high-quality graphene consists of few-layer sheets with a uniform size of less than 1 µm. The obtained graphene was uniformly dispersed and tightly integrated into a polyamide 66 (PA66) matrix to create high-performance multifunctional polymer nanocomposites. The tensile strength and thermal conductivity of 0.3 and 0.5 wt% EG/PA66 composites were found to be ~32.6% and ~28.8% greater than the corresponding values calculated for pure PA66, respectively. This confirms that the new protocol of liquid phase exfoliation of graphite has excellent potential for use in the industrial-scale production of high-quality graphene for numerous applications.

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