MOCVD Growth of ZnO Nanowires Through Colloidal and Sputtered Au Seed Via Zn[TMHD]2 Precursor

AbstractZinc oxide (ZnO) nanowire (NW) arrays were grown on Si (100) substrate by metal-organic chemical vapor deposition (MOCVD) via Zn[TMHD]2 as precursor. Here we adopted two different procedures to grow ZnO NWs namely, colloid and sputtered Au pre-deposition on Si (100) substrate. Comparative studies based on the morphology and growth behavior of ZnO NWs were performed. The grown ZnO NWs were characterized by field-emission scanning electron microscopy (FE-SEM), Atomic Force Microscopy (AFM), Co-focal laser scanning microscopy (CLSM), and Raman spectroscopy

Kerr nonlinearities and nonclassical states with superconducting qubits and nanomechanical resonators

We propose the use of a superconducting charge qubit capacitively coupled to two resonant nanomechanical resonators to generate Yurke-Stoler states, i.e. quantum superpositions of pairs of distinguishable coherent states 180$^\circ$ out of phase with each other. This is achieved by effectively implementing Kerr nonlinearities induced through application of a strong external driving field in one of the resonators. A simple study of the effect of dissipation on our scheme is also presented, and lower bounds of fidelity and purity of the generated state are calculated. Our procedure to implement a Kerr nonlinearity in this system may be used for high precision measurements in nanomechanical resonators.Comment: 5 pages, 2 figures, fixed typo

Luminescence Dynamics of Silica-Encapsulated Quantum Dots During Optical Trapping

"This document is the Accepted Manuscript version of a Published Work that appeared in final form in The Journal of Physical Chemistry C, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.jpcc.6b11867."[EN] The trade-off between photobrightening and photobleaching controls the emission stability of colloidal quantum dots. This balance is critical in optical trapping configurations, where irradiances that confine and simultaneously excite the nanocrystals in the focal region cannot be indefinitely lowered. In this work, we studied the photobrightening and bleaching behaviors of two types of silica-encapsulated quantum dots excited upon two-photon absorption in an optical trap. The first type consists of alloyed CdSeZnS quantum dots covered with a silica shell. We found that the dynamics of these as-prepared architectures are similar to those previously reported for bare surface-deposited quantum dots, where thousands of times smaller irradiances were used. We then analyzed the same quantum dot systems treated with an extra intermediate sulfur passivating shell for the better understanding of the surface traps influence in the temporal evolution of their emission in the optical trap. We found that these latter systems exhibit better homogeneity in their photodynamic behavior compared to the untreated ones. These features strengthen the value of quantum dot preparations in optical manipulation as well as for applications where both long and maximal emission stability in physiological and other polar media are required.The authors thank A. Blanco and D. Granados for fruitful discussion and S. de Lorenzo for technical help. H.R-R. is supported by an FPI-UAM fellowship and M. A. by a contract from Fundacion IMDEA Nanociencia. The research leading to these results has received funding from the Spanish Ministry of Economy and Competitiveness (grant numbers MAT2015-71806-R and FIS2015-67367-C2-1-P), from Comunidad de Madrid (S2013/MIT-2740) and from UAM-Banco Santander (CEAL-AL/2015-15).Rodríguez-Rodríguez, H.; Acebrón, M.; Juárez, B.; Arias-Gonzalez, JR. (2017). Luminescence Dynamics of Silica-Encapsulated Quantum Dots During Optical Trapping. The Journal of Physical Chemistry C. 121(18):10124-10130. https://doi.org/10.1021/acs.jpcc.6b11867S10124101301211

Epicuticular lipids induce aggregation in Chagas disease vectors

<p>Abstract</p> <p>Background</p> <p>The triatomine bugs are vectors of the protozoan parasite <it>Trypanosoma cruzi</it>, the causative agent of Chagas disease. Aggregation behavior plays an important role in their survival by facilitating the location of refuges and cohesion of aggregates, helping to keep them safely assembled into shelters during daylight time, when they are vulnerable to predators. There are evidences that aggregation is mediated by thigmotaxis, by volatile cues from their faeces, and by hexane-extractable contact chemoreceptive signals from their cuticle surface. The epicuticular lipids of <it>Triatoma infestans </it>include a complex mixture of hydrocarbons, free and esterified fatty acids, alcohols, and sterols.</p> <p>Results</p> <p>We analyzed the response of <it>T. infestans </it>fifth instar nymphs after exposure to different amounts either of total epicuticular lipid extracts or individual lipid fractions. Assays were performed in a circular arena, employing a binary choice test with filter papers acting as aggregation attractive sites; papers were either impregnated with a hexane-extract of the total lipids, or lipid fraction; or with the solvent. Insects were significantly aggregated around papers impregnated with the epicuticular lipid extracts. Among the lipid fractions separately tested, only the free fatty acid fraction promoted significant bug aggregation. We also investigated the response to different amounts of selected fatty acid components of this fraction; receptiveness varied with the fatty acid chain length. No response was elicited by hexadecanoic acid (C16:0), the major fatty acid component. Octadecanoic acid (C18:0) showed a significant assembling effect in the concentration range tested (0.1 to 2 insect equivalents). The very long chain hexacosanoic acid (C26:0) was significantly attractant at low doses (≤ 1 equivalent), although a repellent effect was observed at higher doses.</p> <p>Conclusion</p> <p>The detection of contact aggregation pheromones has practical application in Chagas disease vector control. These data may be used to help design new tools against triatomine bugs.</p

Validation of the Use of SEBS Blends as a Substitute for Liquid Silicone Rubber in Injection Processes

Liquid silicone rubber is an interesting material at an industrial level, but there are great difficulties in the design and machining of molds, and in addition, it cannot be processed using conventional equipment. Therefore, new lines of research have focused on the search for new materials capable of providing final properties similar to liquid silicone rubber, that can also be engineered using simple, conventional processes and machinery. In this investigation, a range of compatible blends, based on two commercial grades of styrene-b-ethyleneco- butylene-b-styrene (SEBS) thermoplastic elastomer, was studied in order to obtain a range of different Shore A hardness blends for industrial applications where liquid silicone rubber (different hardness) is currently used. The two blended elastomers used had widely differing Shore A hardness values (5 and 90). Once the blended materials had been characterized, the Cross and Williams et al. [20] (Cross-WLF) mathematical model was applied in order to obtain theoretical performance curves for the viscosity of each of the blends. After this, a model was developed using the Computer Aided Engineering (CAE) software package Autodesk Moldflow 2012TM. This computer modeling validated the results obtained from the mathematical models, thus making available to process engineers the full range of hardnesses necessary for industrial products (where liquid silicone rubber is used), while still providing the advantages of thermoplastic injection molding.The authors wish to thank "Ministerio de Ciencia e Innovacion" IPT-310000-2010-37 and Universidad Politecnica de Valencia PAID 10012 for their financial support.Juárez Varón, D.; R. Balart; T. Boronat; Reig Pérez, MJ.; Ferrándiz Bou, S. (2013). Validation of the Use of SEBS Blends as a Substitute for Liquid Silicone Rubber in Injection Processes. Materials and Manufacturing Processes. 28(11):1215-1221. doi:10.1080/10426914.2013.811732S121512212811Zhang, B., Wong, J. S.-P., Shi, D., Yam, R. C.-M., & Li, R. K.-Y. (2010). Investigation on the mechanical performances of ternary nylon 6/SEBS elastomer/nano-SiO2hybrid composites with controlled morphology. Journal of Applied Polymer Science, 115(1), 469-479. doi:10.1002/app.30185Su, F.-H., & Huang, H.-X. (2009). Mechanical and rheological properties of PP/SEBS/OMMT ternary composites. Journal of Applied Polymer Science, 112(5), 3016-3023. doi:10.1002/app.29875Sugimoto, M., Sakai, K., Aoki, Y., Taniguchi, T., Koyama, K., & Ueda, T. (2009). Rheology and morphology change with temperature of SEBS/hydrocarbon oil blends. Journal of Polymer Science Part B: Polymer Physics, 47(10), 955-965. doi:10.1002/polb.21699Jose, A. J., Alagar, M., & P. Thomas, S. (2012). Preparation and Characterization of Organoclay Filled Polysulfone Nanocomposites. Materials and Manufacturing Processes, 27(3), 247-254. doi:10.1080/10426914.2011.585490Ivanović, N., Marjanović, N., Grbović Novaković, J., Manasijević, M., Rakočević, Z., Andrić, V., & Hadžić, B. (2009). Experimental and Theoretical Investigations of Cured and Uncured Disiloxane Bisbenzocyclobutene Thin Films. Materials and Manufacturing Processes, 24(10-11), 1180-1184. doi:10.1080/10426910902978811Perisić, M., Radojević, V., Uskoković, P. S., Stojanović, D., Jokić, B., & Aleksić, R. (2009). Wood–Thermoplastic Composites Based on Industrial Waste and Virgin High-Density Polyethylene (HDPE). Materials and Manufacturing Processes, 24(10-11), 1207-1213. doi:10.1080/10426910903032212Iqbal, H., Sheikh, A. K., Al-Yousef, A., & Younas, M. (2012). Mold Design Optimization for Sand Casting of Complex Geometries Using Advance Simulation Tools. Materials and Manufacturing Processes, 27(7), 775-785. doi:10.1080/10426914.2011.648250Özek, C., & Çelık, Y. H. (2011). Calculating Molding Parameters in Plastic Injection Molds with ANN and Developing Software. Materials and Manufacturing Processes, 27(2), 160-168. doi:10.1080/10426914.2011.560224Hirschmanner, M., Mörwald, K., & Fröhlich, C. (2011). Next Generation Mold Level Control: Development of LevCon 2.0. Materials and Manufacturing Processes, 26(1), 169-174. doi:10.1080/10426910903206691Selvakumar, P., & Bhatnagar, N. (2009). Studies on Polypropylene/Carbon Fiber Composite Foams by Nozzle-Based Microcellular Injection Molding System. Materials and Manufacturing Processes, 24(5), 533-540. doi:10.1080/10426910902742738Gramegna, N., Corte, E. D., & Poles, S. (2011). Manufacturing Process Simulation for Product Design Chain Optimization. Materials and Manufacturing Processes, 26(3), 527-533. doi:10.1080/10426914.2011.564248Marković, G., Radovanović, B., Marinović-Cincović, M., & Budinski-Simendić, J. (2009). The Effect of Accelerators on Curing Characteristics and Properties of Natural Rubber/Chlorosulphonated Polyethylene Rubber Blend. Materials and Manufacturing Processes, 24(10-11), 1224-1228. doi:10.1080/10426910902967087Mehat, N. M., & Kamaruddin, S. (2011). Investigating the Effects of Injection Molding Parameters on the Mechanical Properties of Recycled Plastic Parts Using the Taguchi Method. Materials and Manufacturing Processes, 26(2), 202-209. doi:10.1080/10426914.2010.529587Chen, C.-C., Su, P.-L., Chiou, C.-B., & Chiang, K.-T. (2011). Experimental Investigation of Designed Parameters on Dimension Shrinkage of Injection Molded Thin-Wall Part by Integrated Response Surface Methodology and Genetic Algorithm: A Case Study. Materials and Manufacturing Processes, 26(3), 534-540. doi:10.1080/10426914.2010.530331Martinez, A., Castany, J., & Aisa, J. (2011). Characterization of In-Mold Decoration Process and Influence of the Fabric Characteristics in This Process. Materials and Manufacturing Processes, 26(9), 1164-1172. doi:10.1080/10426914.2010.536934Primo Benitez-Rangel, J., Trejo-Hernández, M., Alberto Morales-Hernández, L., & Domínguez-González, A. (2010). Improvement of the Injection Mold Process by Using Vibration Through a Mold Accessory. Materials and Manufacturing Processes, 25(7), 577-580. doi:10.1080/10426910903124902Chen, C.-C. (2011). Design of Effective Parameters on the Wick-Debinding Process for Powder Injection Molded Green Compact. Materials and Manufacturing Processes, 26(10), 1261-1268. doi:10.1080/10426914.2010.544826Boronat, T., Segui, V. J., Peydro, M. A., & Reig, M. J. (2009). Influence of temperature and shear rate on the rheology and processability of reprocessed ABS in injection molding process. Journal of Materials Processing Technology, 209(5), 2735-2745. doi:10.1016/j.jmatprotec.2008.06.013Cross, M. M. (1965). Rheology of non-Newtonian fluids: A new flow equation for pseudoplastic systems. Journal of Colloid Science, 20(5), 417-437. doi:10.1016/0095-8522(65)90022-xReig, M. J., Segui, V. J., & Zamanillo, J. D. (2005). Rheological Behavior Modeling of Recycled ABS/PC Blends Applied to Injection Molding Process. Journal of Polymer Engineering, 25(5). doi:10.1515/polyeng.2005.25.5.43