Muhammad M. Rahman  Anand B. Puthirath  Aparna Adumbumkulath  Thierry Tsafack  Hossein Robatjazi  Morgan Barnes  Zixing Wang  Sampath Kommandur  Sandhya Susarla  Seyed Mohammad Sajadi  Devashish Salpekar  Fanshu Yuan  Ganguli Babu  Kazuki Nomoto  SM Islam  Rafael Verduzco  Shannon K. Yee  Huili G. Xing  Pulickel M. Ajayan 《Advanced functional materials》2019,29(28)

Polymer dielectrics find applications in modern electronic and electrical technologies due to their low density, durability, high dielectric breakdown strength, and design flexibility. However, they are not reliable at high temperatures due to their low mechanical integrity and thermal stability. Herein, a self‐assembled dielectric nanocomposite is reported, which integrates 1D polyaramid nanofibers and 2D boron nitride nanosheets through a vacuum‐assisted layer‐by‐layer infiltration process. The resulting nanocomposite exhibits hierarchical stacking between the 2D nanosheets and 1D nanofibers. Specifically, the 2D nanosheets provide a thermally conductive network while the 1D nanofibers provide mechanical flexibility and robustness through entangled nanofiber–nanosheet morphologies. Experiments and density functional theory show that the nanocomposites through thickness heat transfer processes are nearly identical to that of boron nitride due to synergistic stacking of polyaramid units onto boron nitride nanosheets through van der Waals interactions. The nanocomposite sheets outperform conventional dielectric polymers in terms of mechanical properties (about 4–20‐fold increase of stiffness), light weight (density ≈1.01 g cm^?3), dielectric stability over a broad range of temperature (25–200 °C) and frequencies (10³–10⁶ Hz), good dielectric breakdown strength (≈292 MV m^?1), and excellent thermal management capability (about 5–24 times higher thermal conductivity) such as fast heat dissipation.  相似文献   

    

Soroosh Sharifi‐Asl  Fernando A. Soto  Tara Foroozan  Mohammad Asadi  Yifei Yuan  Ramasubramonian Deivanayagam  Ramin Rojaee  Boao Song  Xuanxuan Bi  Khalil Amine  Jun Lu  Amin Salehi‐khojin  Perla B. Balbuena  Reza Shahbazian‐Yassar 《Advanced functional materials》2019,29(23)

LiCoO₂ is a prime example of widely used cathodes that suffer from the structural/thermal instability issues that lead to the release of their lattice oxygen under nonequilibrium conditions and safety concerns in Li‐ion batteries. Here, it is shown that an atomically thin layer of reduced graphene oxide can suppress oxygen release from Li_xCoO₂ particles and improve their structural stability. Electrochemical cycling, differential electrochemical mass spectroscopy, differential scanning calorimetry, and in situ heating transmission electron microscopy are performed to characterize the effectiveness of the graphene‐coating on the abusive tolerance of Li_xCoO₂. Electrochemical cycling mass spectroscopy results suggest that oxygen release is hindered at high cutoff voltage cycling when the cathode is coated with reduced graphene oxide. Thermal analysis, in situ heating transmission electron microscopy, and electron energy loss spectroscopy results show that the reduction of Co species from the graphene‐coated samples is delayed when compared with bare cathodes. Finally, density functional theory and ab initio molecular dynamics calculations show that the rGO layers could suppress O₂ formation more effectively due to the strong C? O_cathode bond formation at the interface of rGO/LCO where low coordination oxygens exist. This investigation uncovers a reliable approach for hindering the oxygen release reaction and improving the thermal stability of battery cathodes.  相似文献   

    

Rui Xia  Zhaofu Fei  Nikita Drigo  Felix D. Bobbink  Zhangjun Huang  Rokas Jasinas  Marius Franckevi ius  Vidmantas Gulbinas  Mounir Mensi  Xiaodong Fang  Cristina Roldn‐Carmona  Mohammad Khaja Nazeeruddin  Paul J. Dyson 《Advanced functional materials》2019,29(22)

Recent years have witnessed considerable progress in the development of solar cells based on lead halide perovskite materials. However, their intrinsic instability remains a limitation. In this context, the interplay between the thermal degradation and the hydrophobicity of perovskite materials is investigated. To this end, the salt 1‐(4‐ethenylbenzyl)‐3‐(3,3,4,4,5,5,6,6,7,7,8,8,8‐tridecafluorooctylimidazolium iodide (ETI), is employed as an additive in hybrid perovskites, endowing the photoactive materials with high thermal stability and hydrophobicity. The ETI additive inhibits methylammonium (MA) permeation in methylammonium lead triiodide (MAPbI₃) occurring due to intrinsic thermal degradation, by inhibiting out‐diffusion of the MA⁺ cation, preserving the pristine material and preventing decomposition. With this simple approach, high efficiency solar cells based on the unstable MAPbI₃ perovskite are markedly stabilized under maximum power point tracking, leading to greater than twice the preserved efficiency after 700 h of continuous light illumination and heating (60 °C). These results suggest a strategy to tackle the intrinsic thermal decomposition of MAI, an essential component in all state‐of‐the‐art perovskite compositions.  相似文献   

    

Shengxian Li  Xiangru Feng  Jixue Wang  Weiguo Xu  Mohammad Ariful Islam  Tianmeng Sun  Zhigang Xie  Chunxi Wang  Jianxun Ding  Xuesi Chen 《Advanced functional materials》2019,29(49)

Nanoparticle‐adjuvanted cancer vaccines are attracting increasing attention because they can induce an effective anticancer immune response. Single‐antigen vaccines are inefficient to inhibit cancer progression due to the heterogeneity of tumors and the antigenicity alteration of tumor‐associated antigens. Therefore, the efficient delivery of multiple antigens to antigen‐presenting cells is an excellent opportunity for strong anticancer immunity. In this study, three immunoadjuvant‐loaded multiantigenic nanoparticles MANPs/R837 with different diameters, i.e., 83, 103, and 122 nm, are prepared through coating of the cancer cell membrane as a source of multiple antigens onto the imiquimod R837‐loaded poly(lactic‐co‐glycolic acid) nanoparticles. The MANP/R837 with a diameter of 83 nm (MANP83/R837) shows the most efficient delivery of the payload to the draining lymph nodes and achieves the best antigen presentation to T lymphocytes. Compared with the other two nanovaccines, MANP83/R837 has a stronger inhibitory effect on tumor growth and metastasis. In the combination therapy with checkpoint blockade therapy using programmed cell death‐1 antibody, MANPs/R837 show effective inhibition against tumor progression, and MANP83/R837 achieves the most exciting effect. Therefore, MANPs/R837, as a promising therapeutic cancer vaccine, demonstrates great prospects in cancer immunotherapy.  相似文献   

    

Mohammad Ali Karambeigi  Narges Fallah  Manouchehr Nikazar  Riyaz Kharrat 《Petroleum Science and Technology》2019,37(20):2146-2149

Asphaltene deposition has a significant detrimental effect on oilfield production. The key to effective treatment of asphaltene deposition is recognition of the problem. Asphaltene and effective treatment can be identified and quantified using laboratory methods. The most commonly way to asphaltene precipitation reduction is applying an asphaltene inhibitor. Most researchers investigate the effect of asphaltene inhibitors on fluid and precipitation reduction in static tests. This study is a coherent approach to measure effect of asphaltene precipitation on reservoir permeability and survey effect of asphaltene inhibitors on damage permeability.  相似文献   

    

Alireza Baghban  Amin Piri  Mostafa Lakzaei  Mohammad Baghban 《Petroleum Science and Technology》2019,37(11):1231-1237

The increasing global energy demand and declination of oil reservoir in recent years cause the researchers attention focus on the enhancement of oil recovery approaches. One of the extensive applicable methods for enhancement of oil recovery, which has great efficiency and environmental benefits, is carbon dioxide injection. The CO₂ injection has various effects on the reservoir fluid, which causes enhancement of recovery. One of these effects is extraction of lighter components of crude oil, which straightly depends on solubility of hydrocarbons in carbon dioxide. In order to better understand of this parameter, in this study, Least squares support vector machine (LSSVM) algorithm was developed as a novel predictive tool to estimate solubility of alkane in CO₂ as function of carbon number of alkane, carbon dioxide density, pressure, and temperature. The predicting model outputs were compared with the extracted experimental solubility from literature statistically and graphically. The comparison showed the great ability and high accuracy of developed model in prediction of solubility.  相似文献   

    

Mohammad Ghashghaee  Samira Shirvani  Mehdi Ghambarian  Ali Eidi 《Petroleum Science and Technology》2019,37(16):1910-1916

A two-stage thermocatalytic upgrading process using a novel catalyst was investigated to produce light olefins and liquid fuels from fuel oil. The upgraded oil from the first thermal stage demonstrated lower viscosity and higher crackability compared to the virgin feedstock. In the next step, the vapor-phase catalytic cracking of the upgraded fraction was implemented over a novel nanoporous composite catalyst, characterized by the XRD, FTIR, NH₃- TPD, and N₂ physisorption techniques. In total, more than 55?wt% of light olefins, particularly propylene (25.5?wt%) together with 25.4?wt% and 32.5?wt% of gasoline and diesel fuel were obtained in this process.  相似文献   

    

Peyman Rostami  Mohammad Sharifi  Babak Aminshahidy  Jalal Fahimpour 《石油科学(英文版)》2019,16(4):859-873

The applications of nanotechnology in oilfields have attracted the attention of researchers to nanofluid injection as a novel approach for enhanced oil recovery. To better understand the prevailing mechanisms in such new displacement scenarios, micromodel experiments provide powerful tools to visually observe the way that nanoparticles may mobilize the trapped oil. In this work, the effect of silicon oxide nanoparticles on the alteration of wettability of glass micromodels was investigated in both experimental and numerical simulation approaches. The displacement experiments were performed on the original water-wet and imposed oil-wet (after aging in stearic acid/n-heptane solution) glass micromodels. The results of injection of nanofluids into the oil-saturated micromodels were then compared with those of the water injection scenarios. The flooding scenarios in the micromodels were also simulated numerically with the computational fluid dynamics (CFD) method. A good agreement between the experimental and simulation results was observed. An increase of 9% and 13% in the oil recovery was obtained by nanofluid flooding in experimental tests and CFD calculations, respectively.  相似文献   

    

Yousef Kazemzadeh  Behnam Dehdari  Zahra Etemadan  Masoud Riazi  Mohammad Sharifi 《石油科学(英文版)》2019,(3):578-590

Nanofluids because of their surface characteristics improve the oil production from reservoirs by enabling different enhanced recovery mechanisms such as wettability alteration, interfacial tension (IFT) reduction, oil viscosity reduction, formation and stabilization of colloidal systems and the decrease in the asphaltene precipitation. To the best of the authors’ knowledge, the synthesis of a new nanocomposite has been studied in this paper for the first time. It consists of nanoparticles of both SiO₂ and Fe₃O₄. Each nanoparticle has its individual surface property and has its distinct effect on the oil production of reservoirs. According to the previous studies, Fe₃O₄ has been used in the prevention or reduction of asphaltene precipitation and SiO₂ has been considered for wettability alteration and/or reducing IFTs in enhanced oil recovery. According to the experimental results, the novel synthesized nanoparticles have increased the oil recovery by the synergistic effects of the formed particles markedly by activating the various mechanisms relative to the use of each of the nanoparticles in the micromodel individually. According to the results obtained for the use of this nanocomposite, understanding reservoir conditions plays an important role in the ultimate goal of enhancing oil recovery and the formation of stable emulsions plays an important role in oil recovery using this method.  相似文献   

    

Rana Afkhami  Mohammad Goli  Javad Keramat 《Food Science & Nutrition》2019,7(7):2353-2360

The objective here is to enrich orange juice through encapsulated lime by‐product extract (LBE) through freeze‐drying, in order to increase lime by‐product consumption, in addition to increasing nutrition value of orange juice. The properties of both the LBE and microparticles are measured. The total polyphenolic compound (TPC) was measured to be 34.5 ± 0.5 (mg gallic acid/g LBE). The obtained value of encapsulation efficiency (EE) was within the 55%–70% range. The encapsulation method was satisfactory. The particle size is within 10–21 μm range, and differences between all treatments were statistically notable (p < 0.05). The lack of melting peaks in the thermal profiles by differential scanning calorimeter (DSC) of microparticles confirmed that hesperidin was well embedded in the polymeric cover. According to the sensory evaluations of orange juice which was enriched with LBE microparticles, the bitter taste was not perceived in some treatments.  相似文献