Thin, rectangular C60 nanorods in face‐centered cubic structure are synthesized by using m‐xylene as a shape controller. These unusual nanorods (see figure) can easily grow on various substrates. The smallest nanorods have widths smaller than 30 nm. The nanorods are highly crystalline in single phase. A significant expansion of the lattice constant is also found in the C60 nanorods when their widths decrease below about 80 nm.

Single-crystalline C 60 ‚1m-xylene nanorods with a hexagonal structure were successfully synthesized by evaporating a C 60 solution in m-xylene at room temperature. The ratio of the length to the diameter of the nanorods can be controlled in the range of ≈10 to over 1000 for different applications. The photoluminescence (PL) intensity of the nanorods is about 2 orders of magnitude higher than that for pristine C 60 crystals in air. Both UV and Raman results indicate that there is no charge transfer between C 60 and m-xylene. It was found that the interaction between C 60 and m-xylene molecules is of the van der Waals type. This interaction reduces the icosahedral symmetry of C 60 molecule and induces strong PL from the solvate nanorods.

Abstract:Observed rainfall and flow data from the Dongjiang River basin in humid southern China were used to investigate runoff changes during low-flow and flooding periods and in annual flows over the past 45 years. We first applied the non-parametric Mann-Kendall rank statistic method to analyze the change trend in precipitation, surface runoff and pan evaporation in those three periods. Findings showed that only the surface runoff in the low-flow period increased significantly, which was due to a combination of increased precipitation and decreased pan evaporation. The Pettitt-Mann-Whitney statistical test results showed that 1973 and 1978 were the change points for the low-flow period runoff in the Boluo sub-catchment and in the Qilinzui sub-catchment, respectively. Most importantly, we have developed a framework to separate the effects of climate change and human activities on the changes in surface runoff based on the back-propagation artificial neural network (BP-ANN) method from this research. Analyses from this study indicated that climate variabilities such as changes in precipitation and evaporation, and human activities such as reservoir operations, each accounted for about 50% of the runoff change in the low-flow period in the study basin.

High-pressure Raman studies have been carried out on single crystalline C(60)(Fc)(2) nanosheets up to 25.4 GPa. Our results show that the charge transfer between Fc (ferrocene) and C(60) increases in the low-pressure range. Above 5 GPa, C(60) molecules start to form a chainlike polymer structure, and this polymerization is reversible upon decompression, in contrast to that of pristine C(60). The special layered structure of C(60)(Fc)(2) restricts the polymerization of C(60) molecules in some directions and explains the formation of the linear chainlike polymeric structure of the C(60) lattice under pressure. We suggest that the reversible polymerization is related to the increased charge transfer and the overridden steric repulsion of counterions.

The most popular practice for analysing nonstationarity of flood series is to use a fixed single-type probability distribution incorporated with the time-varying moments. However, the type of probability distribution could be both complex because of distinct flood populations and time-varying under changing environments. To allow the investigation of this complex nature, the time-varying two-component mixture distributions (TTMD) method is proposed in this study by considering the time variations of not only the moments of its component distributions but also the weighting coefficients. Having identified the existence of mixed flood populations based on circular statistics, the proposed TTMD was applied to model the annual maximum flood series of two stations in the Weihe River basin, with the model parameters calibrated by the meta-heuristic maximum likelihood method. The performance of TTMD was evaluated by different diagnostic plots and indexes and compared with stationary single-type distributions, stationary mixture distributions and time-varying single-type distributions. The results highlighted the advantages of TTMD with physically-based covariates for both stations. Besides, the optimal TTMD models were considered to be capable of settling the issue of nonstationarity and capturing the mixed flood populations satisfactorily. The most optimal model with time or physically-based covariates is highlighted in bold. Stationarity in the last column means the situation where distribution parameters do not vary with explanatory variables. 78 L. YAN ET AL.