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Leaching is the continuous separation of elements from the mineral surface which is composed of coordination polyhedrons of atoms. The interaction between surface elements and the leaching agent is the prerequisite for separation. Density functional theory calculations are used to reveal the interaction between leaching agent ions (H+), activator agent ions (Mn4+), and the vanadium-containing biotite surface. According to the calculation results, the oxidative activation acid-leaching process is simulated. In the oxidative activation acid-leaching process, the surface oxygen atoms first absorb hydrogen ions to complete the hydroxylation process and then combines hydrogen ions again to form water molecules. And when the surface tetrahedron has oxygen defects, the oxidant ions can further corrode the tetrahedral structure with oxygen defects. This corrosion can destroy tetrahedral structures. When the tetrahedral structure is destroyed, cations are released from the mineral surface into the solution. In this study, the corrosion behavior of the oxidant ion and its effect on the leaching rate is found. The separation of atoms from the surface under oxidative activation leaching environments is simulated at the atomic level, and the mechanism of the activated leaching process is revealed by electron probe, scanning electron microscopy, infrared, and other methods.

Myelodysplastic syndromes (MDS) are a class of myeloid neoplasms featuring inefficient maturation and differentiation of hematopoietic cells, blood cytopenia, and a high risk of leukemia onset. The diagnosis of MDS remains a challenging task owing to its complexity, heterogeneity, and the lack of specific characteristics.To look for an easy and inexpensive diagnostic method for MDS, we tried to establish an FCM scoring systems (FCSS) with a combination of antibodies for diagnosis and prognostic stratification of MDS. This FCSS adopted four parameters; i.e., the frequency of myeloblasts in nucleated cells, the ratio between pro-B cells and CD117+ cells, the ratio of CD45 mean fluorescence intensity between lymphocytes and myeloblasts, and the ratio of SSC peak values between mature granulocytes and lymphocytes.We tested the correlation between the total FCSS score with conventional IPSS-R. Additionally, the correlation between the score of each FCSS parameter and IPSS-R was also evaluated. We found that total FCSS score had a positive correlation with IPSS-R, while FCSS parameter 1 and 4 were also correlated with IPSS-R. Furthermore, this FCSS had a sound sensitivity and specificity in the diagnosis of MDS.The FCSS represents a convenient and affordable approach for the diagnosis and prognostic stratification of MDS.

The development of phase change material (PCM) for battery thermal management poses key limitations on its reliability caused by leakage and shape deformation under high temperature. In this work, ...

Controllable nitrogen doping is an effective way to regulate the electronic properties of graphene and further to facilitate its wider application. However, the synthesis of high-quality nitrogen-doped graphene (NG) with a controllable nitrogen configuration still faces considerable challenges. In this work, we present for the first time a simple method for the one-step synthesis of NG with ionic liquids (ILs) as precursors, which avoids the defects introduced by secondary doping and simplifies the process. Using 1-Ethyl-3-methylimidazolium dicyanamide (EMIM-dca) as the precursor, we obtained a high-quality NG with few defects (I

Based on the online travel notes released by tourists, using social network analysis, this article analyses the spatial structure characteristics of tourist flow network under the county-level administrative units in Guangxi. The results show that:(1) The density of tourist flow network in Guangxi is sparse, and the tourist flow is dominated by landscape sightseeing tours and coastal holiday tours. (2) Nanning, Guilin, Beihai and Yangshuo are the core nodes of tourism system in Guangxi, which not only have great tourism attraction, but also have strong resource control capabilities. (3) Guangxi tourism presents a significant clustering phenomenon. The tourist flow is extremely uneven. The popularity of scenic spots has an important impact on the node flows. The level of the regional transportation network determines the central position of the node in the network to a large extent.

According to the characteristics of clay vanadium ore, a novel process of no-grinding and no-roasting direct activated acid leaching under atmospheric pressure, was proposed. And in order to improve the leaching efficiency of vanadium, new activator MF was added into the acid leaching process. The effects of main factors on acid leaching of vanadium were investigated. The results showed that the leaching efficiency of vanadium reached 96.14 % under the conditions as follows: mass ratio of manganese oxide to fluoride is 25 %: 75 %, activator dosage of 3 %, H2SO4 dosage of 25 %, leaching temperature of 90 ℃, and leaching time of 5 h. The leaching kinetics was studied by using the unreacted shrinking core model. It was found that under the optimum conditions, the control step of direct activated acid leaching of vanadium from clay vanadium ore is changed from hybrid control to diffusion control, the apparent activation energy is reduced from 36.30 kJ‧mol−1 to 12.54 kJ∙mol−1, and the reaction order of sulfuric acid is reduced from 2.9033 to 1.8114.

Flexible composite phase change materials (CPCMs) can minimize the thermal contact resistance in battery thermal management. However, these “thermally-induced” flexible CPCMs only present well-flexibility above the phase change temperature, which is unfavorable to the flexible assembly of the cells and battery modules with variable specifications. Herein, a kind of flexible CPCM with well-retained flexibility in a wide temperature range is prepared by carefully selecting a copolyester thermoplastic elastomer with polyether soft segment (TPC-et) to replace the conventional olefin block copolymer (OBC) skeleton. The internal rotation resistance of the ether bond in TPC-et is much lower than that of the C–C bond in OBC, thus giving rise to a better flexibility in room and low temperatures from 20 to −5 ℃. Combining the room-temperature-flexibility with the high thermal conductivity of 1.64 W m−1 K−1, enough latent heat of 102 J g−1 and suitable phase change region of 40–50 ℃, the obtained TPC-et based flexible CPCM shows outstanding applicability and cooling performance to various cells and battery modules through facile installations. The maximum temperature of the cylindrical, prismatic and pouch battery modules with TPC-et based CPCM is 51.5, 42.1 and 50.0 ℃, respectively, 4.0, 3.9 and 5.4 ℃ lower than the modules using rigid CPCM, respectively.

In this study, density functional theory (DFT) was used to investigate the separation mechanism of sphalerite and pyrite in the presence of sodium dithionite. The results showed that S atoms were preferred over Zn atoms on the ZnS (1 1 0) surface, but, the S atom was less reactive than the Fe atom on the FeS2 (1 0 0) surface. The S atom played a key role in interactions with atoms on the mineral surface. No orbital hybridization occurred between the S 3p and O 2p orbitals of S2O42–, and the Zn 3d orbitals on the ZnS (1 1 0) surface. Strong chemical interactions occurred between S, O, and Fe, via the hybridization of the S 3s, 3p, and O 2p orbitals of S2O42– and the Fe 3p, 3d, and 4s orbitals on the FeS2 (1 0 0) surface. In the presence of S2O42– prevented the collector from being effectively adsorbed by active particles on the surface of pyrite, which changed the hydrophobicity of pyrite. In the flotation experiments, the S2O42– ion was used as an inhibitor for pyrite to separate zinc and sulfur.

In order to gain a deeper understanding of the decoupling change trajectory of the industrial environment pollution and industrial economic growth in Guangxi Beibu Gulf Economic Zone, and to better solve the problem of sustainable economic development under the concept of low-carbon economy, based on the decoupling theory, six major indicators such as COD, ammonia nitrogen, SO2, NOx, PM and industrial added value were selected to conduct the empirical analysis of the decoupling relationship between industrial environmental pollution and industrial economic growth in Guangxi Beibu Gulf Economic Zone from 2009 to 2016. The results showed that they were basically in an unstable state of incomplete decoupling, most of which were manifested as strong decoupling, accompanied by other types of decoupling, and no obvious evolutionary law. In terms of time, the decoupling reached its best in 2013 and 2016. In terms of space, the decoupling in Nanning was the best.

China is facing serious heavy metal pollution in farmland soil, which is a major pressing concern for food safety and human health. This research delivers an integrated methodology for pollution source apportionment and a soil-rice-human model to predict heavy metal transfer in the farmland soil, rice grain and human blood chain. The source identification integrated positive matrix factorization (PMF), cluster analysis (CA) and the life cycle assessment (LCA) survey of agricultural and industrial production and consumption. Based on the case analysis of Shaoxing, this method showed very good performance through the illustration of the source contributions by PMF and LCA at county level and the identification of the pollution sources using CA and LCA at field scale. According to the overall evaluation, the integrated method was superior for the farmland metals pollution source identification comparing to existing source apportionment methods. To predict metal transformation in soil-rice-human chain, a set of models of metals (As, Pb, Cd, Hg, Cr) accumulation ability in rice grain and human blood has been established by literature review and monitoring data. The models showed adequate predictability for the metal content of rice grains at both the field and regional scale, and plausible simulation of the metal concentration in human blood throughout the whole study region. Therefore, this study provides valuable tools for farmland soil heavy metal pollution source identification and for the prediction of heavy metal transformation in soil-rice-human chain; and it can highlight the need to take mitigating action to reduce farmland metal pollution risks in specific regions.

This paper presents a framework for decentralized control of self-organizing swarm systems based on the artificial potential functions (APFs). In this scheme, multiple agents in a swarm self-organize to flock and achieve formation control through attractive and repulsive forces among themselves using APFs. In particular, this paper presents a set of analytical guidelines for designing potential functions to avoiding local minima for a number of representative scenarios. Specifically the following cases are addressed: 1) a case that the potential of the goal is overwhelmed by the potential of an obstacle, 2) a case that the potential of the obstacle is overwhelmed by the potential of the goal, 3) a case that the potential of the obstacle is overwhelmed by potential of other robots in a group formation and 4) a case that the potential of the robot in a formation is overwhelmed by potential of the goal.

This paper presents a general framework for the coordinated motion control of autonomous swarms in the presence of obstacles. The proposed framework judiciously combines concepts and techniques from potential flows, artificial potentials and dynamic connectivity to realize complex swarm behaviors. To begin with, existing concepts from potential flows in fluid mechanics are used to solve the single-agent navigation problem. As an extension, an analytical solution to the stagnation point problem is provided. The potential flow based framework is then modified significantly to facilitate the coordinated control of swarms navigating through multiple obstacles. Artificial potentials are employed for swarming as well as enhanced obstacle avoidance. A novel concept of dynamic connectivity is utilized to improve the performance of obstacle avoidance (Line of Sight Connectivity) and to organize diverse swarm behaviors (Probabilistic Connectivity). Simulation results with a set of developed algorithms are included to illustrate the viability of the proposed framework.

In this paper, we present a framework for managing group behaviors in multi-agent swarm systems. The framework explores the benefits by integrating stream function based path planning methods with novel artificial potential based flocking methods to realize complex swarming behaviors. A key development is the introduction of a set of flocking by dynamic association (DA) algorithms that effectively deal with a host of swarming issues such as flexible and agile formation, obstacle avoidance and inter-agent collision. In particular, the DA algorithms employ a so-called singular association (SA) rule for inter-agent interaction, i.e., each agent associates itself with only one other judiciously chosen agent. The resulting algorithms enjoy two important interrelated benefits. First, the SA rule greatly simplifies the interactions in swarm systems thus it is more readily to pursue rigorous analysis of such systems, some of which are included in this paper. Secondly, the simplicity of the SA rule is advantageous for practical implementations. Extensive simulation as well as preliminary experimental results are presented to illustrate the viability of the proposed framework.