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All‐Carbon Nanoarchitectures as High‐Performance Separation Membranes with Superior Stability
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Kunli Goh Wenchao Jiang Huseyin Enis Karahan Shengli Zhai Li Wei Dingshan Yu Anthony G. Fane Rong Wang Yuan Chen 《Advanced functional materials》2015,25(47):7348-7359
The application of graphene‐based membranes is hindered by their poor stability under practical hydrodynamic conditions. Here, nanocarbon architectures are designed by intercalating surface‐functionalized, small‐diameter, multi‐walled carbon nanotubes (MWCNTs) into reduced graphene oxide (rGO) sheets to create highly stable membranes with improved water permeability and enhanced membrane selectivity. With the intercalation of 10 nm diameter MWCNTs, the water permeability reaches 52.7 L m?2 h?1 bar?1, which is 4.8 times that of pristine rGO membrane and five to ten times higher than most commercial nanofiltration membranes. The membrane also attains almost 100% rejection for three organic dyes of different charges. More importantly, the membrane can endure a turbulent hydrodynamic flow with cross‐flow rates up to 2000 mL min?1 and a Reynolds number of 4667. Physicochemical characterization reveals that the inner graphitic walls of the MWCNTs can serve as spacers, while nanoscale rGO foliates on the outer walls interconnect with the assimilated rGO sheets to instill superior membrane stability. In contrast, intercalating with single‐walled nanotubes fails to reproduce such stability. Overall, this nanoarchitectured design is highly versatile in creating both graphene‐rich and CNT‐rich all‐carbon membranes with engineered nanochannels, and is regarded as a general approach in obtaining stable membranes for realizing practical applications of graphene‐based membranes. 相似文献
114.
Keewah Chan Zarina AspanutBoontong Goh Muhamad Rasat MuhamadSaadah A. Rahman 《Thin solid films》2011,519(15):4952-4957
Nanostructured materials fabricated by dispersing metal particles on the dielectric surface have potential application in the field of nanotechnology. Interfacial metal particles/dielectric matrix interaction is important in manipulating the structural and optical properties of metal/dielectric films. In this work, a thin layer of gold (Au) was sputtered onto the surface of silicon oxide, SiOx (0.38 < x < 0.68) films which was deposited at different N2O/SiH4 flow rate ratios of 5 to 40 using plasma enhanced chemical vapor deposition (PECVD) technique prior to the annealing process at 800 °C. FTIR spectra demonstrate the intensity and full-width at half-maximum (FWHM) of Si-O-Si stretching peaks are significantly dependent on the N2O/SiH4 flow-rate ratio, η. The films deposited at low and high N2O/SiH4 flow rate ratios are dominated by the oxygen and silicon contents respectively. The size and concentration of Au particles distributed on the surface of SiOx films are dependent on the N2O/SiH4 flow-rate ratio. High concentrations of Au nanoparticles are distributed evenly on the surface of the film deposited at N2O/SiH4 flow-rate ratio of 30. Crystallinity and crystallite sizes of Au are enhanced after the thermal annealing process. Appearance of surface plasma resonance (SPR) absorption peaks at 524 nm for all samples are observed as a result of the formation of Au particles. The annealing process has improved SPR peaks for all the as-deposited films. The energy gap of the as-deposited Au/SiOx films are in the range of 3.58 to 4.38 eV. This energy gap increases after the thermal annealing process except for the film deposited at η = 5. 相似文献
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Thirty-two male goats were randomly assigned to four dietary treatments namely, basal diet 70% concentrate and 30% oil palm fronds (control, CN), CN + 400 mg/kg vitamin E (VE), 0.5% turmeric (TU) or 0.5% Anderographis paniculata (AP). After 100 days of feeding, the goats were slaughtered and longissimus dorsi (LD) muscle was sampled. The muscle was vacuum-packaged and conditioned for 0, 7 and 14 days in a chiller (4 °C). The drip loss of the LD muscle increased (P < 0.05) with aging time. Meat tenderness was improved (p < 0.05) at 14 days aging. All antioxidant supplements improved (P < 0.05) colour of the meat. The TBARS value increased (P < 0.05) at 7 days of aging while the fatty acid composition was not affected by the dietary supplements. It is concluded that TU and AP are potential dietary antioxidant supplements, for the purpose of improving the quality of chevon. 相似文献
116.
Published field experimental data [11, 15, 19] were used to compare measured NH3(g) losses following applications of urine or aqueous urea to pasture soils with values predicted by a simplified ammonia volatilization model [16]. Total measured losses were generally in close agreement with predictions. For example, predicted losses following applications of urine to a ryegrass-white clover pasture in Canterbury, New Zealand were 20.7% in summer and 22.4% in autumn and were highly correlated with measured losses of 21.5% and 24.4% respectively (r = 0.998).The model was also tested for instantaneous rate of ammonia gas loss at 33 discrete sampling times for the summer experiment. Correlations were again highly significant (r = 0.951 for urine and r = 0.885 for urea).The interception of urine solution by herbage and litter on the pasture surface is discussed and was shown to account for some of the discrepancies between measurements and predictions. Soil surface pH was confirmed as an important factor in determining the extent of ammonia gas loss, and the practicalities of measuring this parameter under field conditions are presented. It was concluded that the model offers the potential for predicting ammonia volatilization losses following urine or aqueous urea applications to short pasture in non-leaching, non-nitrifying environments. 相似文献
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OBJECTIVE: To compare depression and conduct disorder symptoms between North American Native and non-Native children as rated by teacher, parent, and self-reports. METHOD: The sample included 1,251 Native children in grades 2 and 4 in four different settings across North America and comparison samples of 457 non-Native children. Parents, teachers, and children rated children's mental health using culturally sensitive measures of depression and conduct disorder symptoms. RESULTS: According to parent ratings and child self-reports, there were no Native/non-Native differences in levels of conduct disorder symptoms. However, non-Native teachers rated higher levels of conduct disorder symptoms among Native children compared with non-Native students. Children reported higher levels of depression than the adults rating them. CONCLUSIONS: Results challenge assertions about high levels of psychopathology among Native youngsters. Cultural distance may introduce a negative bias in teacher evaluations of Native children's mental health. 相似文献
118.
The Software Engineering Initiative, process-improvement program undertaken by the Software Systems Laboratory in Raytheon's equipment division in mid-1988 is reviewed. The three phases of the program are the process-stabilization phase, in which the emphasis is on distilling the elements of the process actually being used and progressively institutionalizing it across all projects, the process-control phase, in which emphasis shifts to instrumenting projects to gather significant data and analyze the data to understand how to control the process, and the process-change phase, in which the emphasis is on determining how to adjust the process as a result of measurement analysis and how to diffuse the new methods among practitioners. It is shown that the process-improvement initiative has improved the equipment division's bottom line, increased productivity, and changed the corporate culture. Much of the savings came from reducing rework 相似文献
119.
Thomas Von Raumer Jean Michel Dion Luc Dugard 《International Journal of Adaptive Control and Signal Processing》1993,7(5):435-455
In this paper we present two adaptive non-linear speed control algorithms for induction motors. They employ input-output linearization techniques for the motor model in the stator fixed reference frame. The first control algorithm directly tracks speed and rotor flux. The second is designed using torque and rotor flux tracking and is extended for speed control. A key point is that this algorithm ensures exact current limitation in the known parameter case. The adaptation based on Lyapunov design can cope with rotor and stator resistance variations. Significant simulations using sampled controllers are presented emphasizing adaptation and current limitation effects. 相似文献
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