Combining Lattice Boltzmann method and genetic algorithm to optimize the layout of artificial floating islands in river network in China.

How to solve the pollution problem of water environment in river network is a hot issue in the world. Artificial floating island is an efficient way to deal with water pollution. Taking Jiashan, Zhejiang, China, as an example, Lattice Boltzmann method (LBM) is used to simulate the law of hydrodynamics and pollutant transport in river network. Lattice Boltzmann equations are established in both artificial floating island and non-artificial floating island sections, and the river network boundary is automatically identified. The simulation results have high accuracy and are more suitable for the establishment of complex boundaries. On this basis, combined with the genetic algorithm (GA) module, the location of the artificial floating island is optimized, and the retention ratio of the pollution in optimized layout of artificial floating island is between and 2.4 and 7.2%. The research results of this paper can provide theoretical reference for the selection and location of artificial floating island in practical engineering.

Synergistic effects of nano-structured WO3-Se heterojunction decorated by organic Nafion layer on improving photoelectrochemical performance.

Exploration of high-performance photoanodes is considered as an essential challenge in photoelectrochemical (PEC) water splitting due to the complex four-electron reaction in water oxidation. Herein, the nano-structured WO3-Se heterojunction decorated by organic Nafion layer is designed. The optimized WO3-Se200-0.05Nafion photoanode shows a remarkable photocurrent of 1.40 mA cm-2at 1.23 V versus reversible hydrogen electrode, which is 2.5-fold higher than that of pure WO3nanosheets (WO3NS) photoelectrode. Remarkably, the photocurrent increments of WO3-Se200-0.05Nafion is larger than the increment sum of WO3-Se200 and WO3-0.05Nafion, which affirming the synergistic effect of Se nanospheres and Nafion layer. The improved PEC performances are attributed to the quick charge separation and transfer, the increased electric conductivity, and the excellent kinetics of oxygen evolution, which is derived from the strong interaction among WO3, Se and Nafion. Meanwhile, the better visible-light harvesting from Se nanospheres as photosensitizer and the induction of transparent Nafion as a passivation layer can explain this synergy. It hopes this heterostructure design with organic Nafion decoration can inspire to exploit outstanding performance photoanodes for PEC water splitting.

Role of satellite and reanalysis precipitation products in streamflow and sediment modeling over a typical alpine and gorge region in Southwest China.

Satellite and reanalysis precipitation products, as new and complementary data sources, are attractive for hydro-meteorological applications, especially in data-sparse areas. This study evaluates the accuracy of two satellite precipitation products (TMPA 3B42V7 and PERSIANN-CDR) and one reanalysis precipitation product (NCEP-CFSR) against gauge precipitation observations with four statistical indices over the upstream of the Lancang River Basin (ULRB), Southwest China. The reliability and applicability of these precipitation products as inputs to a hydrological model (Soil and Water Assessment Tool, SWAT) for streamflow and sediment simulations are also assessed. Furthermore, we compare the spatial plots of extreme water yield (99 percentiles) and suspended sediment yield (99 percentiles) driven by the four precipitation sources, and investigate the spatial and temporal variability of water yield and suspended sediment yield over the ULRB. Results show that for direct comparisons with gauge precipitation observations, monthly TMPA 3B42V7 precipitation product performs the best at the basin scale with the smallest error and bias, and the highest correlation, followed by NCEP-CFSR, and PERSIANN-CDR. For modeling-based indirect inference, TMPA 3B42V7 presents great capability for streamflow and sediment simulations in the SWAT model on a monthly time step at the basin outlet, and PERSIANN-CDR also performs well. NCEP-CFSR shows acceptable skills in modeling sediment but unacceptable skills in modeling streamflow. Extreme water yield presents moderate spatial variability over the ULRB while extreme suspended sediment yield presents strong spatial variability. Water yield of this basin shows a decreasing trend during 1998-2008 while there is no obvious trend in suspended sediment yield in this period.

Measurement of contact angles at room temperature in high magnetic field.

The contact angle (CA) goniometer adaptable to a superconducting magnet was developed based on the sessile drop method. The goniometer mainly consisted of the sampling system, the supporting system, and the image acquisition system. Some improvements were taken to avoid the effects of the magnetic field (MF) on the CA measurement. As an example, the CAs of water on two substrates of silica and polymethyl methacrylate (PMMA) were measured using the goniometer. The results with and without a MF showed a good repeatability and reliability. Additionally, the MF was found to reduce the CA of water, which probably stemmed from the change of the surface tension in the MF. The CA goniometer will become an important tool which is used to study the wettability of liquids on a solid in the MF.

Alternating-magnetic-field induced enhancement of diffusivity in Ni-Cr alloys.

For applying an alternating magnetic field (AMF) in materials processing it is of high significance to understand the physical mechanisms behind the change in diffusivity in the AMF. In this work, the effect of the AMF on interdiffusion in a Ni-Cr alloy was investigated with a diffusion couple. The interdiffusion coefficient was found to increase with increasing AMF intensity. The faster diffusivity is a consequence of the enhancement of the dislocation density in the diffusion couples that was confirmed by the broadening of X-ray diffraction peaks. The higher dislocation density is attributed to the magnetoplastic effect (MPE). Theoretical considerations on the relation of MPE, dislocation density and diffusivity are in agreement with the experimental results.

A new furostanol saponin from Asparagus cochinchinensis.

A new furostanol saponin, (25S)-26-O-ß-D-glucopyranosyl-5ß-furost-20(22)-en-3ß, 15ß,26-triol-3-O-[α-L-rhamnopyranosyl-(1-4)]-ß-D: -glucopyranoside, namely, aspacochioside D (1) were isolated from Asparagus cochinchinensis (Lour.) Merr, along with three known saponins, aspacochioside C (2), (25S)-5ß-spirostan-3ß-yl-O-[O-α-L-rhamnopyranosyl-(1-4)]-ß-D-glucopyranoside (3), and pseudoprotoneodioscin (4). The structure of 1 was elucidated on the basis of chemical reactions and spectral analysis (IR, GC, ESI-MS, (1)H-NMR, (13)C-NMR, DEPT, HMBC, HMQC and NOESY). The antiproliferative effects of 1-4 were evaluated in a cytotoxicity assay against the human tumor cell line, A549. Compound 2 (Aspacochioside C) exhibited moderate cytotoxicity against A-549, with an IC(50) value of 3.87 µg/mL.

[Studies on the separation and purificaton of pumiloside from Nauclea officinalis by macroreticular resin].

OBJECTIVE: To investigate the technological parameters and the process for separation and purification of pumiloside (PML) from Nauclea officinalis Pierrc ex Pitard by macroreticular resin. METHODS: PML was extracted by hot water, and the content of PML was determinated by HPLC method. The static capacity absorption, static elution ratios of five types of resin were studied respectively, and were compared to evaluate their absorption and desorption effect to PML. And then the absorption capacity, elution solution and elution volume of the AB-8 resin were researched to set up the optimum separation process for PML. Finally, PML was recrysallized from MeOH and identified by spectra analysis. RESULTS: The AB-8 resin had the best absorptive and separative properties to PML. The dynamic absorption ratio was 2.44 mg/g. The applicable process was as follows: the water extracted solution of Nauclea officinalis flow through the resin column repeatedly, after being eluted with 6BV of distilled water, the resin column was eluted with 4BV 30% ethanol, the 30% ethanol fraction was combined and the solvent was recovered in vacuum. The precipitation was filtered and recrysallized from MeOH to give pure PML. The yield of PML was 75.1%, and the product purity was up to 99.5%. CONCLUSION: AB-8 resin shows better comprehensive absorption property. It can be used for separation and purification of PML from Nauclea officinalis successfully.

[A new indole alkaloid glycoside from stems of Nauclea officinalis].

AIM: To investigate the chemical constituents of water-soluble part of stem of Nauclea officinalis. METHODS: The compounds were isolated and purified by resins, silica gel, and Sephadex LH20 column chromatography repeatedly, and their structures were identified by spectral analysis. RESULTS: Seven compounds were isolated and identified as: naucleamide A-10-O-beta-D-glucopyranoside (I), 5-beta-carboxystrictosidin (II), sweroside (III), loganin (IV), 3,4-dimethoxyphenyl-beta-D-glucopyranoside (V), 3, 4, 5-trimethoxyphenyl-beta-D-glucopyranoside (VI), 2-phenethylrutinoside (VII). CONCLUSION: Compound I is a new indole alkaloid glucoside, compounds I-VII were isolated from this plant for the first time.

Lignans from Trachelospermum jasminoides.

Seven lignans having a diarylhydroxybutyrolactone skeleton were isolated from the leaves and stems of Trachelospermum jasminoides (Lindl.) Lem. Their structures were elucidated to be nortrachelogenin 8' -O-beta-D-glucopyranoside (1), nortrachelogenin 5'- C- beta-D-glucopyranoside (2), trachelogenin amide (3), nortracheloside, trachelogenin, tracheloside, and trachelogenin 4'- O- beta-gentiobioside, respectively, on the basis of spectroscopic analyses. Lignans 1 - 3 were structurally identified to be new compounds, and 2 was a rare C-glucosyl-lignan.

[Studies on chemical constituents of Ervatamia hainanensis].

OBJECTIVE: To study the chemical constituents of Ervatamia hainanensis. METHOD: The compounds were separated and purified by column chromatography with silica gel, and identified by IR, MS, NMR and 2D-NMR. RESULT: Five compounds were identified as I (isolariciresinol 9-O-beta-D-glucopyranoside), II (cycloartenol), III (beta-amyrin acetate), IV (beta-sitosterol), V (daucosterol), respectively. CONCLUSION: All the compounds were isolated from this plant for the first time.