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61.
Nonionic surfactants are capable of forming nano‐range vesicles upon self‐assembling in an aqueous medium. These vesicles are highly stable, low in toxicity, and cost‐effective. Owing to their ability to solubilize both hydrophilic and hydrophobic substances, they are of great interest for drug solubilization and delivery. This study describes the synthesis and characterization of two new nonionic surfactants and their screening for biocompatibility and drug loading potentials in nano‐scale niosomal vesicles. They were characterized through mass spectroscopy, 1HNMR, and FT‐IR. Their critical micelle concentration (CMC) was investigated using UV–vis spectrophotometry. The biocompatibility study was carried out through blood hemolysis and in vitro cytotoxicity assays. The surfactants have very low CMC values, are highly hemo‐compatible, and were nontoxic when tested against a cell culture. They were able to form nano‐range niosomal vesicles with large variation in their size. Both new surfactants were able to encapsulate increased amounts of the drug, in this case clarithromycin. The chemical nature of the drug remained intact in the niosomal vesicles. The results suggest that these nonionic surfactants could be promising drug delivery vehicles.  相似文献   
62.
    
Epoxy/nanocrystalline diamond nanocomposites composites were prepared by dispersing ultrasonically, 0.4, 0.7, 1.0, and 4.0 wt% acid‐treated nanocrystalline diamond (NCD) powder in epoxy matrix. Fourier infrared spectroscopy was utilized to study the moieties attached to the nanodiamond particles. The trace elements present in NCD powder before and after acid treatment were analyzed by ion beam techniques. Thermomechanical properties of the nanocomposites showed that incorporation of low content (0.4 wt%) of nanodiamond powder into epoxy matrix enhanced the storage modulus, loss modulus, and hardness by ∼68, ∼55, and ∼86%, respectively, over neat epoxy. By increasing the concentration of modified NCD to 0.7 wt% resulted in lower values of hardness and thermomechanical properties but still remain higher than neat epoxy. An increasing trend in properties was again observed at 4 wt% concentration of modified nanofiller. The glass transition temperature was up shifted to ∼110°C over neat epoxy. The mechanisms responsible for enhanced properties of epoxy matrix are also discussed in detail. POLYM. COMPOS., 34:811–818, 2013. © 2013 Society of Plastics Engineers  相似文献   
63.
    
Two types of vinyl silicone oil (VSO), allyl‐capped hyperbranched polycarbosilane (HBP), and triethoxysilane (TES) were employed to synthesize macromolecular silane coupling agent (MMSCA) by hydrosilylation. VSOs, HBP, and the hydrosilylated products were used as crosslinker, respectively, to improve weak mechanical properties of silicone rubber (SR). Structures of the crosslinkers were studied by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR). Crosslinking density test and scanning electron microscope (SEM) observation showed an increased interaction between silicone rubber and fumed silica by the use of MMSCA. Mechanical properties of the resulted composites using MMSCAs were increased to varying degrees compared with those possessing crosslinkers without ethoxy group. MMSCAs were effective for further property enhancements of composites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43415.  相似文献   
64.
    
Surface treatment of cellulose fibers was performed with maleated high oleic sunflower oil (MSOHO). The MSOHO‐treated cellulose fibers and unmodified cellulose fibers were dispersed in styrene butadiene rubber (SBR) using a two roll mill. Vapor grown carbon nanofibers (VGCNF) were also incorporated at only one parts per hundred rubber (phr) in unmodified cellulose fibers/SBR composites. The curing characteristics, mechanical properties, and water absorption of the resulting composites were determined. MSOHO‐treated fibers completed curing at much slower rate and also decreased the cure density of composites, compared to unmodified fibers. In contrast, the combination of VGCNF and unmodified cellulose fibers accelerated the SBR curing process, but reduced the cure density. MSOHO treatment improved the dispersion of the fibers in the SBR, which resulted in improved mechanical properties of composites. The composite incorporating 1 phr VGCNF and 15 phr unmodified cellulose fibers showed the greatest increase in tensile strength as compared with neat SBR. POLYM. COMPOS. 37:1113–1121, 2016. © 2014 Society of Plastics Engineers  相似文献   
65.
66.
Semiconducting-ionic membranes (SIMs) have exhibited significant superiority to replace the conventional ionic electrolytes in solid oxide fuel cells (SOFCs). One interesting phenomenon is that the SIMs can successfully avoid the underlying short-circuiting issue and power losses while bringing significantly enhanced power output. It is crucial to understand the physics in such devices as they show distinct electrochemical processes with conventional fuel cells. We first presented experimental studies of a SIM fuel cell based on a composite of semiconductor LiCo0.8Fe0.2O2 (LCF) and ionic conductor Sm-doped CeO2 (SDC), which achieved a remarkable power density of 1150 mW cm?2 at 550 °C along with a high open circuit voltage (OCV) of 1.04 V. Then, for the first time we used a physical model via combining a semiconductor-ionic contact junction with a rectifying layer which blocks the electron leakage to describe such unique SIM device and excellent performance. Current and power are the most important characteristics for the device, by introducing the rectifying layer we described the SIM physical nature and new device process. This work presented a new view on advanced SIM SOFC science and technology from physics.  相似文献   
67.
The novel core–shell nanostructured SDC/Na2CO3 composite has been demonstrated as a promising electrolyte material for low-temperature SOFCs. However, as a nanostructured material, stability might be doubted under elevated temperature due to their high surface energy. So in order to study the thermal stability of SDC/Na2CO3 nanocomposite, XRD, BET, SEM and TGA characterizations were carried on after annealing samples at various temperatures. Crystallite sizes, BET surface areas, and SEM results indicated that the SDC/Na2CO3 nanocomposite possesses better thermal stability on nanostructure than pure SDC till 700 °C. TGA analysis verified that Na2CO3 phase exists steadily in the SDC/Na2CO3 composite. The performance and durability of SOFCs based on SDC/Na2CO3 electrolyte were also investigated. The cell delivered a maximum power density of 0.78 W cm−2 at 550 °C and a steady output of about 0.62 W cm−2 over 12 h operation. The high performances together with notable thermal stability make the SDC/Na2CO3 nanocomposite as a potential electrolyte material for long-term SOFCs that operate at 500–600 °C.  相似文献   
68.
The catalyst has a significant role in gas processing applications such as reforming technologies for H2 and syngas production. The stable catalyst is requisite for any industrial catalysis application to make it commercially viable. Several methods are employed to synthesize the catalysts. However, there is still a challenge to achieve a controlled morphology and pure catalyst which majorly influences the catalytic activity in reforming applications. The conventional methods are expansive, and the removal of the impurities are major challenges. Nevertheless, it is not straightforward to achieve the desired structure and stability. Therefore, significant interest has been developed on the advanced techniques to take control of the physicochemical properties of the catalyst through non-thermal plasma (NTP) techniques. In this review, the systematic evolution of the catalyst synthesis using NTP technique is elucidated. The emerging DBD plasma to synthesized and effective surface treatment is reviewed. DBD plasma synthesized catalyst performance in reforming application for H2 and syngas production is summarised. Furthermore, the status of DBD plasma for catalyst synthesis and proposed future avenues to design environmentally suitable and cost-effective synthesis techniques are discussed.  相似文献   
69.
    
Capacity of a radio relay channel has been extensively studied. Although general solution to the capacity problem is still elusive, solution for a physically degraded relay channel is available. This paper presents the original results for lower and upper bounds on the capacity of an optical wireless relay channel. Optical intensity communication uses signals that are inherently non‐negative and are governed by average and peak power constraints dictated by the considerations of battery life and safety of human eye. The component optical wireless links of the relay channel are assumed to be Gaussian, a valid assumption for intensity modulation direct detection model. The decode‐and‐forward inner bounds are developed through entropy power inequality. The concept of duality of capacity is employed for determining the min–max cut upper bound. Two sets of upper bounds have been worked out using a non‐zero mean Gaussian and a piecewise continuous measure comprising Gaussian and exponential components on the channel output. As maximum entropy measure for a peak and mean power‐constrained channel depends on mean‐to‐peak power ratio α, separate set of bounds have been computed for and . It is shown that high signal asymptotes of upper and lower bounds tend to converge. The maximum gap between the two asymptotic bounds is half a bit. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
70.
    
This research aims to study the effect of ammonium polyphosphate and expandable graphite on the intumescent coating formulations (ICF). The coating presented in this research article is based on carbon source expandable graphite (EG), blowing agent melamine, acid source ammonium polyphosphate (APP), epoxy resin as a binder with polyamide amine. The stability of the developed coating was verified at 950°C for 1-hour fire test. The results showed that the coating is stable and well bond with the steel substrate. The char was characterized by using FESEM, XRD, FTIR, DTA, TGA, XPS, Py-GCMS and Weathering Test. The morphology of the char was studied by SEM of the coating after furnace fire test. XRD and FTIR show the presence of graphite, borophosphate; boron oxide and sassolite in the residual char. TGA and DTG disclosed that EG improved the residual mass of coating. XPS analysis showed the char residue of IF5-APP-EG contains carbon and oxygen contents 47.50 and 40.70, respectively. Py-GCMS analysis described that the IF5-APP-EG released less gaseous compounds. The weathering test illustrated that's the char expansion of coatings samples was decreased due to the presence of a humid environment and UV light. The IF5-APP-EG showed the maximum char expansion, lower substrate temperature and high residual weight among the studied formulations.  相似文献   
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