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In this study, the morphology and sorption behavior of polyethylene terephthalate (PET) microplastics during the aging process are investigated. To clarify the sorption mechanism of aged PET microplastics, the common sunblock 4-methylbenzylidene camphor (4-MBC) was chosen as the target contaminant, and UV irradiation was used for the laboratory aging simulation. The results show that oxygen-containing functional groups (carboxylic, carbonyl, ketone and hydroxyl groups) increase on the surface of aged PET microplastics. Based on density functional theory (DFT) simulations, the camphor part of 4-MBC acts as a hydrogen bond acceptor, whereas the carboxylic group on aged PET microplastics acts as a hydrogen bond donor. The formation of hydrogen bonding causes increased sorption of 4-MBC on aged PET microplastics. The sorption capacity increased from 5 to 11 μg g

This paper is the first research applying the new approach, panel smooth transition regression (PSTR) model, in the field of patent analysis. This study uses PSTR model to verify whether there is a single threshold effect of Herfindahl---Hirschman Index of patents (HHI of patents) on the relationship between patents and market value in the American pharmaceutical industry. The results demonstrate that HHI of patents moderates the relationship between market value and patent performance, patent counts/assets and patent citations/assets. When HHI of patents is less than or equal to the threshold value, 0.3220, the positive relationship between patent performance and market value is lower. Once HHI of patents is more than the threshold value, 0.3220, the positive relationship between patent performance and market value is higher. This study points out that the second regime is optimal because the extent of the positive relationship between patent performance and market value is higher.

This study uses the entropy-based patent measure to discuss the effects of related technological diversification (RTD) and unrelated technological diversification (UTD) on innovation performance and corporate growth. The results indicate that RTD has a monotonically positive influence on both of innovation performance and corporate growth and UTD has an inverse U-shaped influence on both of them. Furthermore, the results show that the extent of the positive effect of RTD on innovation performance and corporate growth is better than that of UTD on both of them. If Taiwan's semiconductor companies would like to undertake technological diversification, this study suggests that they should adopt RTD, rather than UTD. Besides, this study points out that innovation performance mediates the relationship between corporate growth and both of RTD and UTD. It demonstrates that RTD and UTD can directly affect corporate growth or indirectly influence it via innovation performance.

Since the relationship between patents and Tobin's q is confusing, this paper utilizes panel threshold regression model to re-examine the relationship between patent counts/sales and Tobin's q. This study finds out patent citations/sales has a single threshold effect on the relationship between patent counts/sales and Tobin's q in the US pharmaceutical industry. The single threshold value of patent citations/sales is 328.81, and it divides the value of patent citations/sales into two regimes: the first regime (patent citations/sale ? 328.81) and the second regime (patent citations/sale > 328.81). The results indicate that patent counts/sales positively affect Tobin's q in the two regimes. In addition, this study demonstrates that the extent of the positive effect of patent counts/sales on Tobin's q is different. This study verifies that patent citations/sales moderates the relationship between patent counts/sales and Tobin's q. Once patent citations/sales is below the threshold value, the extent of the positive relationship between patent counts/sales and Tobin's q is the most. Therefore, this study finds out that the first regime is optimal.

Diffusiophoresis in concentrated suspensions of spherical colloids with charge-regulated surface is investigated theoretically. The charge-regulated surface considered here is the generalization of conventional constant surface potential and constant surface charge density situations. Kuwabara's unit cell model is adopted to describe the system and a pseudospectral method based on Chebyshev polynomial is employed to solve the governing general electrokinetic equations. Excellent agreements with experimental data available in literature were obtained for the limiting case of constant surface potential and very dilute suspension. It is found, among other things, that in general the larger the number of dissociated functional groups on particle surface is, the higher the particle surface potential, hence the larger the magnitude of the particle mobility. The electric potential on particle surface depends on both the concentration of dissociated hydrogen ions and the concentration of electrolyte in the solution. The electric potential on particle surface turns out to be the dominant factor in the determination of the eventual particle diffusiophoretic mobility. Local maximum of diffusiophoretic mobility as a function of double layer thickness is observed. Its reason and influence is discussed. Corresponding behavior for the constant potential situation, however, may yield a monotonously increasing profile.

The fingerprint-based techniques are commonly used for indoor location estimation, in which a radio map is built by calibrating signal-strength values at several training locations in the offline phase. However, the signal-strength values change as the environment changes, and hence the radio map built may be out of date. Further, the recalibration of signal-strength values for each environment change is laborious and time consuming. Therefore, in this paper, an efficient radio map management method is proposed in response to the environment changes. We first demonstrate that different features of signal propagation are obtained in different regions of the indoor environment. According to the different features of signal propagation, the environment is divided into several regions and the signal-strength values collected at the training locations in different regions can be updated accurately and individually using proper propagation features. The experimental results show the usefulness of the proposed method and the accuracy of the localization can be improved.