科研成果

Hollow microsphere structure cobalt hydroxide (h-Co(OH)2) was synthesized via an optimized solvothermal-hydrothermal process and applied to activate peroxymonosulfate (PMS) for degradation of a typical pharmaceutically active compound, ibuprofen (IBP). The material characterizations confirmed the presence of the microscale hollow spheres with thin nanosheets shell in h-Co(OH)2, and the crystalline phase was assigned to α-Co(OH)2. h-Co(OH)2 could efficiently activate PMS for radicals production, and 98.6% of IBP was degraded at 10 min. The activation of PMS by h-Co(OH)2 was a pH-independent process, and pH 7 was the optimum condition for the activation-degradation system. Scavenger quenching test indicated that the sulfate radical (SO4• −) was the primary reactive oxygen species for IBP degradation, which contributed to 75.7%. Fukui index (f −) based on density functional theory (DFT) calculation predicted the active sites of IBP molecule for SO4• − attack, and then IBP degradation pathway was proposed by means of intermediates identification and theoretical calculation. The developed hollow Co(OH)2 used to efficiently activate PMS is promising and innovative alternative for organic contaminants removal from water and wastewater.

High-efficiency organic-inorganic hybrid perovskite solar cells have experienced rapid development and attracted significant attention in recent years. However, instability to an ambient environment such as moisture is a facile challenge for the application of perovskite solar cells. Herein, 1,8-octanediammonium iodide (ODAI) is employed to construct a two-dimensional modified interface by in situ combined with residual PbI2 on the formamidinium lead iodide (FAPbI(3)) perovskite surface. The ODA(2+ )ion seems to lie horizontally on the surface of a three-dimensional perovskite due to its substitution for two FA(+) ions, which could protect the bulk perovskite more effectively. The unencapsulated perovskite solar cells showed notably improved stability, which remained 92% of its initial efficiency after storing in an ambient environment for 120 days. In addition, a higher open-circuit voltage of 1.13 V compared to that of the control device (1.04 V) was obtained due to the interface energy level modification and defect passivation. A champion power conversion efficiency of 21.18% was therefore obtained with a stabilized power output of 20.64% at the maximum power point for planar perovskite solar cells.

Effective removal of dyes has been widely investigated by the adsorption of powder activated carbon and photodegradation by titanate nanotubes (TNTs). In this study, a facile one-step alkaline-hydrothermal method was applied to synthesize powder activated charcoal–supported TNTs (TNTs@PAC). Adsorption of three representative dyes, i.e., cationic methylene blue (MB), cationic rhodamine B (RhB), and anionic methyl orange (MO), onto TNTs@PAC was evaluated by the adsorption kinetic experiments and adsorption isotherms. The first 30 min is the main time phase of adsorption, and MB, RhB, and MO obtained the experimental equilibrium uptake of 173.30, 115.06, and 106.85 mg/g, respectively, indicating their final removal efficiencies of 100%, 69.36%, and 64.11%, respectively. The increase of pH value reduced adsorption capacity of MO (from 149.35 mg/g at pH of 2 to 96.99 mg/g at pH of 10), but facilitated MB adsorption, which was attributed to the charge distribution on the surface of TNTs@PAC and the charge of dyes at different pH. Furthermore, good capacity recoveries of MB by TNTs@PAC (>þinspace}99%) were observed after UV irradiation treatment, indicating the used TNTs@PAC can be easily recycled for the adsorption of MB by UV irradiation. Overall, TNTs@PAC is an effective process for remediation of dye-contaminated water because of its adsorption performance for all selected dyes and good regeneration capacity for MB.

The traditional eigen beam based localization algorithms are usually not employed on the non-spherical microphone array, for which the eigen beam is hard to be obtained. In this paper, the transfer functions are introduced to calculated the eigen beam on the non-spherical microphone array. Based on it, three localization algorithms including the eigen beam based intensity vector, eigen beam based beamforming, eigen beam based MUSIC, are employed and their performance on localization are evaluated.

Personalized recommendation has important implications in raising online shopping efficiency and increasing product sales. There has been wide interest in finding ways to provide more efficient personalized recommendations. Most existing studies focus on how to improve the accuracy of the recommendation algorithms, or are more concerned on ways to increase consumer satisfaction. Unlike these studies, our study focuses on the process of decision-making, using long tail theory as a basis, to reveal the mechanisms involved in consumers' adoption of recommendations. This paper analyzes the effect of personalized recommendations from two angles: product sales and ratings, and tries to point out differences in consumer preferences between mainstream products and niche products, high rating products and low rating products, search products and experience products. The study verifies that consumers demand diversity in the recommended content, and also provides suggestions on how to better plan and operate a personalized recommendation system. © 2019 IEEE Computer Society. All rights reserved.

Scholars commonly regard the Comintern as having played a critical role in the emergence of the communist movement in late-colonial Malaya. When discussing the Comintern’s early influence, existing scholarships often use the arrest of Joseph Ducroux — alias Serge Lefranc, a French agent of the Comintern — in Singapore in June 1931 to illustrate the Comintern-China-Malaya connection. Additionally, historians have attached special meanings to the Ducroux Case, primarily because of the more significant repercussions it caused internationally. Laurent Metzger has conducted detailed research on Ducroux’s arrest in and eventual exile from Singapore between 1931 and 1932. While such an account is useful in demonstrating the incident’s international significance, little is known as to what immediate impression it created in the cosmopolitan port city. Moreover, it is also unclear how Singapore’s general public perceived communism when communist organizations had yet firmly established themselves in the British colony. This article seeks to make sense of such issues by investigating how the Singapore press reported on the Ducroux Case.