The diatom test is the most reliable approach that provides scientific support for diagnosis of drowning. However, there are limitations, which, made forensic scientists stop using the test, such as the fact that it is time-consuming and lack of domain knowledge of the diatom identification. This study aims to find different types of diatoms that are commonly present in water bodies in China for a possible application of an automatic forensic diatom test. In total, 119 different water samples were obtained from different locations of the Yellow River, the Yangtze River and the Pearl River (China) and were analysed. About 50ml of water of each sampling site was digested and then observed by a scanning electron microscopy. The diatom genera found in samples were recorded. Twenty-four diatom genera were found in all samples. Among them, Navicula, Nitzschia, Cyclotella, Synedra and Gomphonema were commonly presented (>70%) across the broad geographic regions. Navicula, Nitzschia, Cyclotella, Synedra and Gomphonema would be the main diatoms used in designing an automatic diatom identification system for forensic diatom test.
Selective catalytic hydrogenations are widely used in oil-cut purification and the generation of intermediates for polymer applications. Herein we report novel hybrid nano-structured catalysts Ni/@-CeO2/SBA-15 and Ni/@-CeO2/MCM-22. Ni nanoparticles were anchored on a nano-semiconductor film supported on a highly specific surface carrier, and catalyst activity was evaluated by hydrogenation of styrene, which served as a model reaction. Both catalysts exhibited excellent catalytic performance, approaching that of platinum, palladium and other precious metal catalysts, which was attributed to the synergistic catalysis of metal nanoparticles and the nano-semiconductor film layer. The reactants were completely converted with 100% selectivity over these catalysts under mild reaction conditions. Importantly, both catalysts can be reused many times with 100% selectivity but slightly reduced conversion. This work provides a promising approach for developing non-noble metal nano-structured catalysts.
China is generally considered a safe place: among the safest for foreigners to visit. For local (long-term) residents and for Chinese criminology scholars, China as a country and its individual cities might be safer compared to many of their foreign peers; however, they might not be as safe as some travel agents claim. To show why this is the case, we crawled and geovisualized the 2015-2016 crime records (n =3D 24,803) available to the public online. The geovisualization shows that the seven crimes (n =3D 12,516) that were most likely to be influenced by space in Beijing were aggravated assault, blackmail, cheating and bluffing, dangerous driving, picking quarrels and provoking trouble, robbery and theft. It also shows a Beijing that many might not have known before.
Montmorillonite (Mt) was used as the original material to prepare intercalation compounds with quaternary ammonium surfactant (QAS). The adsorption of zearalenone (ZEA) onto Mt and organomodified Mt was investigated in vitro. Effects of QAS in binding ZEA were studied. By the method of intercalation with dioctadecylmethylbenzylammonium chloride (DOMBAC), the sample exhibited the highest adsorption rate of ZEA (93.2%) which was much higher than that of Mt (10.5%). Several methods were adopted to characterize samples, including XRD, TG/DSC, N-2 adsorption/desorption, and FTIR. Adsorption isotherm parameters were obtained from Langmuir and Freundlich and the adsorption data fitted better to Langmuir. All results indicate that organomodified Mt has great potential to be a high-performance material to control ZEA contamination.
Many researchers have confirmed a correlation between the built environment and physical activity. However, most studies are based on the objective characteristics of the built environment, and seldom involve the residents' subjective perception. The purpose of this study is to explore the relationship between the subjective and objective characteristics of the built environment and physical activity at the community scale. Data consists of that collected from a social survey, Points of Interest (POI), the road network, and land use in Fuzhou, China. The duration of moderate-to-vigorous physical activity (MVPA) within a week is used to represent the general physical activity of residents. Security perception is introduced as an intermediary variable. SPSS software is used for factor analysis and Amos software for statistical analysis. Structural equations are set up to analyse the relationship between these variables. The final results show that: (1) The objective characteristics of the built environment have no direct impact on the development of leisure MVPA, but it can indirectly affect leisure MVPA through residents' subjective perception of the built environment; (2) The subjective perception of residents has a significant impact on the duration of MVPA, the subjective perception of humanized space has a direct impact on the duration of MVPA, and destination accessibility and urban environment maintenance has an indirect impact through community public security perception; and (3) The individuals' attributes such as gender and self-evaluated socioeconomic status have negative effects on the duration of leisure MVPA, and an individual's love of sports has a positive effect on MVPA.
Pd-based catalyst is one of the most widely used catalysts in the selective hydrogenation of phenol. Herein, a new strategy has been developed to fabricate a hybrid nano-structure Pd catalyst. By coating ZrO2 on the activated carbon(AC), then anchored Pd nanoparticles on the ZrO2/AC, a hybrid nano-structure Pd/@-ZrO2/AC catalyst with strong synergy can be obtained. The results show that the Pd/@-ZrO2/AC catalyst exhibited a synergistic effect and remarkable catalytic activity in the selective hydrogenation of phenol, outperforming both conventional Pd/ZrO2 and Pd/AC catalyst. Importantly, the catalytic activity was closely related to the calcination temperature of ZrO2/AC. The ZrO2/AC support was calcined at 500 degrees C with a minimum particle size, which enables Pd nanoparticles to support on it with high dispersion. Then the Pd/@-ZrO2/AC(500) exhibited stronger interaction of Pd nanoparticles with the ZrO2/AC surface as compared to other catalysts and shown the highest catalytic activity. Moreover, a series of this hybrid nano-structure Pd/@-MexOy/AC catalysts(MexOy: TiO2, CeO2, La2O3) have been synthesized and further confirmed the synergistic effect in the selective hydrogenation.
By means of on-site and network investigation, we collected data relevant to residents of communities, point of interest (POI) data, and land-use data of Fuzhou. We set traffic walking time and leisure walking time as an independent variable, built environment as dependent variable, and gender, age, education level and income level as control variables. Six linear regression models were established using Statistical Product and Service Solutions (SPSS). The results showed that in the 5D (i.e., Density, Diversity, Design, Destination and Distance) elements of the built environment, the density was negatively correlated with the traffic walking time, whereas other elements were positively correlated with the walking time, but the degree of influence was different.
Supported metal as a type of heterogeneous catalysts are the most widely used in industrial processes. High dispersion of the metal particles of supported catalyst is a key factor in determining the performance of such catalysts. Here we report a novel catalyst Pd/(F)-MeOx/AC with complex nanostructured, Pd nanoparticles supported on the platelike nano-semiconductor film/activated carbon, prepared by the photocatalytic reduction method, which exhibited high efficient catalytic performance for selective hydrogenation of phenol to cyclohexanone. Conversion of phenol achieved up to more than 99% with a lower mole ratio (0.5%) of active components Pd and phenol within 2 h at 70 degrees C. The synergistic effect of metal nanoparticles and nano-semiconductors support layer and the greatly increasing of contact interface of nano-metal-semiconductors may be responsible for the high efficiency. This work provides a clear demonstration that complex nanostructured catalysts with nanometal and nano-semiconductor film layer supported on high specific surface AC can yield enhanced catalytic activity and can afford promising approach for developing new supported catalyst.