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The burning of fossil fuels leads to the emission of large amounts of CO2 into the air, and how to deal with the increasingly generated CO2 has been a great challenge. In an effort to convert the l...

Electrochemical CO

N-doped porous carbon nanospheres were fabricated directly by pyrolyzing chitin nanogels, which were facilely prepared by mechanical agitation induced sol–gel transition of chitin solution in NaOH/urea solvent. The resulting carbon nanospheres displayed ordered micropores (centered at ∼0.6 nm) and high BET surface area of up to 1363 m2 g−1, which is substantially larger than that of the carbons from raw chitin (600 m2 g−1). In addition, the carbon nanospheres retained a nitrogen content of 3.2% and excellent conductivity. Consequently, supercapacitor electrodes prepared from the carbon nanospheres pyrolyzed at 800 °C showed a specific capacitance as high as 192 F g−1 at a current density of 0.5 A g−1 and impressive rate capability (81% retention at 10 A g−1). When assembled in a symmetrical two-electrode cell, N-doped porous carbon nanospheres demonstrated excellent cycling stability both in aqueous and organic electrolytes (95% retention after 10 000 cycles at 10 A g−1), together with outstanding energy density of 5.1 W h kg−1 at the power density of 2364.9 W kg−1. This work introduces a novel and efficient method to prepared N-doped porous carbon nanospheres directly from chitin and demonstrates the great potential of utilization of abundant polymers from nature in power storage.

Fault diagnosis of satellite attitude control system is an important task to ensure the safe and reliable operation of on-orbit satellites. At present, most fault diagnosis methods are to diagnose independent identically distributed(i.i.d) task objects. However, even if the same device works under different working conditions, the distribution domain of the collected data almost always changes. At the same time, the training of fault diagnosis model under full working conditions can increase the model complexity and training time, and there may unknown working conditions. In view of the above situation, this paper proposed a domain adaptive adversarial deep neural network based fault diagnosis method. By combining the feature extractor, label classifier and domain classifier with the convolutional neural network and gradient inversion layer (GRL), the effective label classification can be achieved while the resolution of different domains can be reduced. We achieved feature extraction of the classification learning task in the source domain and transfer of the classification task between the two domains. The effectiveness of the diagnosis model is verified in the ground simulation data of a certain satellite under different conditions.

The greenhouse gas carbon dioxide (CO2) was converted to a novel CO2 conversion material (electrolytic carbon, EC) by molten salt electrochemical conversion, which served as the carbon source to prepare an iron–carbon composite (Fe–EC). The composite was used to activate persulfate (PS) and degrade 2,4-dichlorophenol (2,4-DCP) in an aqueous solution. The effects of several essential operating parameters such as PS dosage and pH on 2,4-DCP degradation were investigated. The removal efficiency of 2,4-DCP (20 mg L–1) was 97.8% in the presence of Fe–EC (50 mg L–1) and PS (1 mmol L–1). Moreover, the average % reaction stoichiometric efficiency (RSE) (calculated for all selected times 5–60 min) was maintained at 23.07%. Electron paramagnetic resonance (EPR), classical radical scavenging experiments, and density functional theory (DFT) calculations were integrated for a mechanistic study, which disclosed that the active species in the system were identified as SO4⦁–, •OH, and O 2 ⦁ − . Moreover, the iron–carbon micro-electrolysis/PS (ICE-PS) system had a high tolerance to a wide range of pH, which would provide theoretical guidance for the treatment of organic pollutants in practical industrial wastewater.

The electrolytic carbon (E-carbon) derived from greenhouse gas CO 2 in molten carbonates at mild temperature possesses high electrical conductivity and suitable specific surface area. In this work, its potential as catalyst is investigated towards oxygen reduction reaction (ORR). It is revealed that the pristine E-carbon has no electrocatalytic activity for the ORR due to its high surface content of carboxyl group. The carbon was then treated in a Li 2 SO 4 containing Li 2 CO 3 -Na 2 CO 3 -K 2 CO 3 molten salt at 550 °C. Sulfur modified E-carbon was obtained in the melt via a galvanic sulfidation reaction, in which Li 2 SO 4 served as a nontoxic sulfur source and an oxidant. The sulfur modified E-carbon showed a significantly improved electrocatalytic activity. Subsequently, a sulfur/cobalt dual modified carbon with much higher catalysis activity was successfully prepared by treating an E-carbon/CoSO 4 composite in the same melt. The dual modified E-carbon showed excellent catalytic performance with activity close to the commercial Pt/C catalyst but a high tolerance towards methanol.

We identify a method and its mechanism for producing nanostructured graphite via the electrochemical reduction of synthetic flue gas (a mixture of CO2 and SO2) in molten Li2CO3–Na2CO3–K2CO3–Li2SO4 at a relatively low temperature (775 °C), the lowest temperature reported for artificial graphite preparation without a metal or metal compound catalyst.

Liquid–liquid equilibria were determined at 305.15 K for aqueous two-phase systems (ATPSs) containing 1-butyl-4-methylpyridinium tetrafluoroborate + inorganic salts (NaH2PO4·2H2O, (NH4)2SO4, Na2SO4, and Na2HPO4·12H2O) + water. Four nonlinear equations were used to correlate the binodal data, and the binodal curves were used to describe and display the effect of different experimental salts on phase separation. Furthermore, a simple, two-parameter equation, along with the Othmer–Tobias and Bancroft equations, was used to correlate the tie-line data. All the results showed good agreement between the fitting equations and the experimental data. The effect of temperature on the binodal curves and tie-lines for 1-butyl-4-methylpyridinium tetrafluoroborate + Na2SO4 + water systems was studied at T = 298.15, 311.15 and 338.15 K. Additionally, the effect of Gibbs energy on the salting-out ability of the different inorganic salts was discussed. From this study, we concluded that these salting-out abilities decline in the following order: Na2HPO4 > Na2SO4 > (NH4)2SO4 > NaH2PO4. These data may be helpful for the further investigation of ATPSs based on the ionic liquid 1-butyl-4-methylpyridinium tetrafluoroborate. In summary, our study determined the basic extraction data for this aqueous two-phase system and developed a fundamental method for the further study of material separation.

In human-robots interfaces studies have shown that stress caused by these factors results in variations in speaker's pronunciation, making highly reliable speech recognition systems of interface difficult to achieve. In this paper, we focus on the glottal source of stress speech under workload condition. The glottal flow resulted from vibration of the vocal folds is mainly discussed and features derived from glottal source are investigated to separate stressed speech from neutral speech. Experimental results show the proposed features representing glottal source could be able to lead to improvements in classification for the stressed speech.

A new dielectric relaxation called /spl alpha//sub H/ was observed in nylon 11. A dielectric relaxation strength as high as 25300 can be achieved. It is found that the relaxation activation energy E/sub a/ is 21.3 kcal/mole and the relaxation time /spl tau/ is about 0.001 second near the melting point temperature of nylon 11. The Cole-Cole plots of /spl epsiv/' and /spl epsiv/" are approximately semi-circles. The dielectric spectra show that there is no ionic conduction contribution to the relaxation. This /spl alpha//sub H/ relaxation is designated as motion of free amide groups in nylon 11.