Janak Sapkota  Julio Cesar Martinez Garcia  Marco Lattuada 《应用聚合物科学杂志》2017,134(35)

The mechanical reinforcement of nanocomposites containing nanorods‐like fillers such as cellulose nanocrystals (CNCs) is often interpreted by adapting the classical parallel–series model, assuming a simple hyperbolic dependence between the percolation threshold and aspect ratio. However, such assumptions are valid only for nanorods with high aspect ratio and often are misinterpreting the reinforcement obtained at low volume fraction of filler loading. To elucidate this intriguing scenario, we proposed a new approach and validated it by compiling and reinterpreting some of available literature that represent the experimental reinforcement with CNCs. Our approach showed better accuracy, specifically for the cases of CNC nanorods with lower aspect ratio. We conclude that this route permits a more realistic evaluation of the mechanical reinforcement, where a physical parameter accounting the polymer filler association is introduced. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45254.  相似文献   

    

Albert C. Aragonès  Ernesto Medina  Miriam Ferrer‐Huerta  Nuria Gimeno  Meritxell Teixidó  Julio L. Palma  Nongjian Tao  Jesus M. Ugalde  Ernest Giralt  Ismael Díez‐Pérez  Vladimiro Mujica 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(2)

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Javier Vioque  Julio Girón-Calle  Verenice Torres-Salas  Youssef Elamine  Manuel Alaiz 《Journal of Food Biochemistry》2020,44(7):e13271

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Pablo Ares  Hernán Santos  Snežana Lazić  Carlos Gibaja  Iñigo Torres  Sergio Pinilla  Julio Gómez-Herrero  Herko P. van der Meulen  Pablo García-González  Félix Zamora 《Advanced Electronic Materials》2021,7(7):2001177

Hexagonal boron nitride (hBN) has attracted a lot of attention in the past years, thanks to its many remarkable properties. These include the presence of single-photon emitters with superior optical properties, which make it an ideal candidate for a plethora of photonic technologies. However, despite the large number of experimental results and theoretical calculations, the structure of the defects responsible for the observed emission is still under debate. In this work, individual atomic-scale defects in hBN with atomic force microscopy under ambient conditions are visualized and multiple narrow emission lines from optically stable emitters are observed. This direct observation of the structure of the defects combined with density functional theory calculations of their band structures and electronic properties allows associating the existence of several single-photon transitions to the observed defects. The work sheds light on the origin of single-photon emission in hBN that is important for the understanding and tunability of high-quality emitters in optoelectronics and quantum technologies.  相似文献   

    

Julio B. Clempner  Alexander S. Poznyak 《国际计算机数学杂志》2018,95(11):2269-2286

This paper presents a novel method for computing the multi-objective problem in the case of a metric state space using the Manhattan distance. The problem is restricted to a class of ergodic controllable finite Markov chains. This optimization approach is developed for converging to an optimal solution that corresponds to a strong Pareto optimal point in the Pareto front. The method consists of a two-step iterated procedure: (a) the first step consists on an approximation to a strong Pareto optimal point and, (b) the second step is a refinement of the previous approximation. We formulate the problem adding the Tikhonov's regularization method to ensure the convergence of the cost-functions to a unique strong point into the Pareto front. We prove that there exists an optimal solution that is a strong Pareto optimal solution and it is the closest solution to the utopian point of the Pareto front. The proposed solution is validated theoretically and by a numerical example considering the vehicle routing planning problem.  相似文献   

    

Zhekai Deng  Paul B. Umbanhowar  Julio M. Ottino  Richard M. Lueptow 《American Institute of Chemical Engineers》2019,65(3):882-893

Predicting segregation and mixing of polydisperse granular materials in industrial processes remains a challenging problem. Here, we extend the application of a general predictive continuum model that captures the effects of segregation, diffusion, and advection in two ways. First, we consider polydisperse segregating flow in developing steady segregation and in developing unsteady segregation. In both cases, several terms in the model that were zero in the previously examined case of fully developed streamwise-periodic steady segregation in a chute are now non-zero, which makes application of the model substantially more challenging. Second, we apply the polydisperse approach to density polydisperse materials with the same particle size. Predictions of the model agree quantitatively with experimentally validated discrete element method (DEM) simulations of both size polydisperse and density polydisperse mixtures having uniform, triangular, and log-normal distributions. © 2018 American Institute of Chemical Engineers AIChE J, 65: 882–893, 2019  相似文献   

    

Hernán Valle  Raquel Palao-Suay  María Rosa Aguilar  Julio San Román  José Becerra  Bernabé Rivas  Ramalinga Viswanathan Mangalaraja 《应用聚合物科学杂志》2019,136(20):47545

In this article, an improved synthesis strategy of the potent anticancer compound 4,7-dichloro-2-quinolinemethanol (QM) and its acrylate ester 4,7-dichloro-2-quinolinemethylacrylate (AQM) are described. AQM is copolymerized using free-radical polymerization with N-vinyl-2-pyrrolidone (VP) and the copolymers obtained from different molar ratios of monomers are subjected to nanoprecipitation to produce suspensions of nanoparticles (NPs) in phosphate buffered saline (PBS). The smallest and stable NPs are prepared with the AQM-VP copolymers 45:55 and 40:60 (118.9 and 128.7 nm in diameter, respectively) at 1 mg mL⁻¹, and along with AQM and QM, are evaluated for their cytotoxic activity on MDA-MB-453 breast carcinoma cells using MTT bioassay. AQM and QM are highly cytotoxic (IC₅₀: 19 and 41 μM, respectively); however, the NPs are not cytotoxic in the range of the assayed concentrations. These results contribute to the search for new polymeric NPs with potential application as QM delivery systems for the treatment of cancer or other diseases treatable with QM. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47545.  相似文献   

    

Daniel Fernández-Quiroz  Jorge Loya-Duarte  Erika Silva-Campa  Waldo Argüelles-Monal  Andre-í Sarabia-Sainz  Armando Lucero-Acuña  Teresa del Castillo-Castro  Julio San Román  Jaime Lizardi-Mendoza  Alexel J. Burgara-Estrella  Beatriz Castaneda  Diego Soto-Puebla  Martín Pedroza-Montero 《应用聚合物科学杂志》2019,136(32):47831

This work describes the preparation of thermosensitive chitosan-graft-poly(N-vinylcaprolactam) nanoparticles by ionic gelation and their potential use as a controlled drug delivery system, using doxorubicin as a model drug. A systematic study of the effect of the main processing parameters on both the size and thermoresponsive behavior of nanoparticles was investigated. The size of the particles is strongly dependent on the length of the poly(N-vinylcaprolactam) grafted chains and the concentration of the copolymer and crosslinking agent solutions. The molecular structure of the copolymer plays an essential role in the phase transition temperature of the particles, which decreases with the length of PVCL grafted chain. The system displayed proper drug-association parameters, and the drug-loaded nanoparticles exhibited dose-dependent cytotoxicity. A significant increase in the doxorubicin delivery rate was observed above the phase transition temperature (40 °C). These features indicate that these nanoparticles are suitable for the development of a new thermally controlled anti-cancer drug delivery system. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47831.  相似文献   

    

Julio Sánchez  Lina Riffo  Paula Salazar  Bernabé L. Rivas 《应用聚合物科学杂志》2019,136(45):48184

In this investigation, the removal of Mo and V oxyanions was carried out using the polymer-assisted ultrafiltration technique with a poly(acrylamide-co-diallyldimethylammonium chloride) [P(AAm-DDACl)]. As a result, 100% of the Mo and 80% of the V were removed at pH 9 with a polymer:metal molar ratio of 10:1 and an optimal metal concentration of 60 mg L⁻¹. The presence of competitive ions such as phosphate, sulfate, and chloride affected the retention of Mo, decreasing its retention to 60% in all cases. For the V, all competitive ions behaved in a similar way, producing approximately 50% metal removal. The permeate flux was kept almost constant for all solutions (40 to 80 L hm⁻²), which indicates that the optimal retention conditions are stable over time. In addition, the characterization of the P(AAm-DDACl) was carried out using infrared spectroscopy analysis (FTIR), and the morphology of the membrane before and after use was analyzed using scanning electron microscopy, which showed significant changes in its morphology. The energy-dispersive X-ray spectroscopy analysis indicates the presence of Mo and P(AAm-DDACl) in the membrane after use. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48184.  相似文献   

    

Gloria Deicy Muoz‐Snchez  Natalia Hernndez‐Arango  Estefanía Buitrago‐Lopez  Julio Csar Luna  Alejandro Zamora  Fabiana Lora‐Suarez  Jorge Enrique Gmez‐Marín 《Journal of Food Safety》2019,39(6)

This work assessed the risk of protozoa in 10 school restaurants in Armenia (Quindío, Colombia) by analyzing the presence of Cryptosporidium spp, Giardia duodenalis, Blastocystis, and Cyclospora cayetanensis DNA in the food, water, and living and inert surfaces of school restaurants and in stools of children who ate at these restaurants. Of the 213 food, water, and surface samples, 6.6% were positive using PCR to test DNA for Blastocystis; 3.8% for Cryptosporidium spp; 0.9% for G. duodenalis; and 0% for C. cayetanensis. In 187 stool samples analyzed via microscopy from children who attended the restaurants, 40 (21.4%) were positive for Blastocystis and 21 (11.2%) were positive for Giardia spp. Via PCR, 20 (10.7%) were positive for Cryptosporidium and 0 (0%) for C. cayetanensis. A higher positivity in children's stools for Blastocystis spp was correlated with lower compliance in property conditions and for higher positivity of Giardia spp in children's stool was related to lower knowledge by food manipulators. Inspection scores can identify restaurants with higher risk for protozoa infection.  相似文献