Chinese App User’s Needs Profile: From Questionnaire Measurement to Behavior Analysis

With the widespread use of mobile devices, the Apps people install and use could be closely linked to their needs. A precise profile of the needs of the user has become a vital foundation of the experience of the user. Previous studies mainly rely on self-reporting to understand the subjective attitudes of the App user toward a single App. This research combined questionnaire measurement and behavior analysis to profile the needs of the App user from a broader perspective. Based on the theoretical model of previous research studies, study 1 developed a novel needs questionnaire measurement of a Chinese App user, which showed good reliability and validity. In study 2, authorized App usage data were collected to construct the behavioral needs profile of a Chinese user. The results showed that the primary needs of the Chinese user remained a relatively high consistency between the questionnaire and the behavior data. The questionnaire-based and behavioral data-based needs profiles provide a reference for further personalized user experience design

CFD investigation of gas-solids flow in a new fluidized catalyst cooler

In our previous work, a new concept of annular catalyst cooler (ACC) was proposed and validated experimentally, which showed that an internal circulation of solids could be formed by using two gas distributors and both hydrodynamics and heat transfer could be largely improved. The current work simulated detailed hydrodynamics of gas-solids flow to advance our understanding of the ACC by using the two-fluid model. The influences of effective particle diameter dp⁎ and specularity coefficient φ were examined and compared with experimental data. Optimum values of dp⁎ = 170 μm and φ = 0.3 were determined and used in the simulations. Detailed hydrodynamics of gas-solids flow were then obtained, and the influential parameters were examined. The results showed that the proper selection of the ratio of gas velocities and the position of the heat transfer tube were needed to form a stable internal solids circulation in the ACC. The ACC had a combined hydrodynamic feature of up-flow and down-flow catalyst coolers with bigger solids volume fraction and smaller particle resident time, which are beneficial for improving the heat transfer between solids and wall

Identification of Potential Sources of Mercury (Hg) in Farmland Soil Using a Decision Tree Method in China

Identification of the sources of soil mercury (Hg) on the provincial scale is helpful for enacting effective policies to prevent further contamination and take reclamation measurements. The natural and anthropogenic sources and their contributions of Hg in Chinese farmland soil were identified based on a decision tree method. The results showed that the concentrations of Hg in parent materials were most strongly associated with the general spatial distribution pattern of Hg concentration on a provincial scale. The decision tree analysis gained an 89.70% total accuracy in simulating the influence of human activities on the additions of Hg in farmland soil. Human activities—for example, the production of coke, application of fertilizers, discharge of wastewater, discharge of solid waste, and the production of non-ferrous metals—were the main external sources of a large amount of Hg in the farmland soil

Spatial Distribution of Mercury (Hg) Concentration in Agricultural Soil and Its Risk Assessment on Food Safety in China

Soil mercury (Hg) pollution in some areas of China is a serious problem and has aroused a lot of attention on a local scale. However, there are few studies on Hg pollution on a national scale. This study collected 444 published papers during 2005–2015 on Hg concentrations in agricultural soil throughout China, under seven land uses, namely: dry land, paddy field, vegetable field, tea garden, orchard, traditional Chinese medicine field and tobacco field, to assess the spatial distribution of Hg concentration and evaluate its influence on food safety. The averaged Hg concentration (0.108 mg/kg) was higher than its background (0.065 mg/kg), but much lower than the guidelines (GB15618-1995 II) for crop production. The spatial distribution of Hg throughout China showed great variability, with some hotspots due to Hg related mining and smelting activities. According to the Environment Quality Standard for soil in China (GB15618-1995 II), 4.2% of agricultural soil should be abandoned due to Hg pollution, and 2.0% faced a high risk of Hg pollution

Multivalent Aptamer Approach: Designs, Strategies, and Applications

Aptamers are short and single-stranded DNA or RNA molecules with highly programmable structures that give them the ability to interact specifically with a large variety of targets, including proteins, cells, and small molecules. Multivalent aptamers refer to molecular constructs that combine two or more identical or different types of aptamers. Multivalency increases the avidity of aptamers, a particularly advantageous feature that allows for significantly increased binding affinities in comparison with aptamer monomers. Another advantage of multivalency is increased aptamer stabilities that confer improved performances under physiological conditions for various applications in clinical settings. The current study aims to review the most recent developments in multivalent aptamer research. The review will first discuss structures of multivalent aptamers. This is followed by detailed discussions on design strategies of multivalent aptamer approaches. Finally, recent developments of the multivalent aptamer approach in biosensing and biomedical applications are highlighted

Pollution and health risk assessment of heavy metals in urban soil in China

<p>The pollution and potential health risk due to lifetime exposure to heavy metals in urban soil of China were evaluated, based on the urban soil samples collected from published papers from 2005 to 2014. The contamination levels were in the order of Cd > Hg > Cu > Zn > Pb >As > Ni > Cr, and Hg and Cd fell into the category of “moderately contaminated” to “heavily contaminated.” The non-carcinogenic risk for different populations varied greatly, among which children faced high risk, and then the adult female and adult male followed. The hazard index (non-carcinogenic risk) higher than 1.00 occurred in Shanghai, Gansu, Qinghai, Hunan, and Anhui, whereas most of those in northern and western China had low risks. For the carcinogenic risk, Anhui and Ningxia provinces had urban soils exceeding the safe reference (1 × 10⁻⁶–1 × 10⁻⁴). Qinghai and Gansu had high carcinogenic risks since their risk indexes were much closer to the reference, and the others were in low risk.</p

Functional Polyselenoureas for Selective Gold Recovery Prepared from Catalyst-Free Multicomponent Polymerizations of Elemental Selenium

Selenium-containing polymers with fascinating functionalities are highly desired but are rarely developed due to their underexplored synthetic methods. Herein, through careful design of monomer structures and polymerization conditions, a series of catalyst-free multicomponent polymerizations (MCPs) of elemental selenium with aliphatic/aromatic diamines and diisocyanides were reported to directly convert elemental selenium to polyselenoureas with long-term stability, good solubility, well-characterized structures, and unique functionalities. The MCPs enjoy wide monomer scope and fast conversion in 1 min, delivering 18 polyselenoureas with high molecular weights (Mws up to 94 600 g/mol) in high yields (up to 99%). Furthermore, the polyselenoureas can be used for the extraction of Au3+ from mixed metal ion solutions in practical conditions with high selectivity, sensitivity ( 99.99%), and capacity (up to 665.60 mg·Au3+/g) within 1 min, and elemental gold can be further recovered after pyrolysis of the polymer complexes

Impact of Soil Heavy Metal Pollution on Food Safety in China

<div><p>Food safety is a major concern for the Chinese public. This study collected 465 published papers on heavy metal pollution rates (the ratio of the samples exceeding the Grade II limits for Chinese soils, the Soil Environmental Quality Standard-1995) in farmland soil throughout China. The results showed that Cd had the highest pollution rate of 7.75%, followed by Hg, Cu, Ni and Zn, Pb and Cr had the lowest pollution rates at lower than 1%. The total pollution rate in Chinese farmland soil was 10.18%, mainly from Cd, Hg, Cu, and Ni. The human activities of mining and smelting, industry, irrigation by sewage, urban development, and fertilizer application released certain amounts of heavy metals into soil, which resulted in the farmland soil being polluted. Considering the spatial variations of grain production, about 13.86% of grain production was affected due to the heavy metal pollution in farmland soil. These results many provide valuable information for agricultural soil management and protection in China.</p></div

Statistical information of the heavy metal pollution rate.

<p>* This data was cited from the Bulletin of National Soil Pollution Survey, 2014</p><p>** This data was cited from the published paper by Niu et al. (2013).</p><p>Statistical information of the heavy metal pollution rate.</p