Search

Coal fly ash (CFA) in some areas contains higher levels of rare earth elements (REEs), which can be seen as a potential substitute for rare earth resources. As an effective method of hydrometallurgy, alkali fusion has been widely used in the recovery of precious metals from secondary resources. In this study, taking a CFA sample and five REEs named Y, La, Ce, Pr, and Nd in the sample as objects, the mechanism of alkali fusion processes of CFA with different alkali fluxes (Na2CO3, NaCl, Na2O2, NaOH, KOH, and Ca(OH)2) was studied. The results showed that Na2CO3, Na2O2, NaOH, and KOH can destroy the structure of CFA to effectively improve the leaching efficiency of REEs from CFA. The total leaching efficiency of the five REEs can reach to 57.45%, 49.25%, 74.23%, and 64.93%, respectively, when these four alkalis were used as fluxs. In addition, with DSC analysis, the non-model fitting dynamics Kissinger method was used to calculate the kinetic parameters of alkali fusion reaction between CFA and Na2CO3. The calculated alkali fusion activation energy E was 895.52 kJ·mol−1, the pre-exponential factor A was 3.47 × 1041 min−1, and the reaction rate constant K was 1.68 min−1. [ABSTRACT FROM AUTHOR]

Soft carbons with porous structure have attracted increasing attention as attracting anode active materials for sodium-ion battery. However, the reported anode active materials are plagued by limited capacity and unsatisfying rate performance. Besides, the improvement of electrical conductivity is often performed by post treatment, which is time-consuming and high cost. Herein we report an one-pot fabrication of pitch-derived soft carbon using zinc acetate as hard templates. Zinc acetate can not only play a vital role in constructing hierarchical porous structure but also providing additional sp2 carbon during carbonization, resulting in significantly enhanced sodium-ion storage capacity and improved rate performance. As anode active materials for sodium-ion battery, the as-prepared soft carbon with hierarchical porous structure, rich sp2 carbon and doped N, O heteroatoms, exhibits an impressively high reversible capacity of 293 mAh g−1 at 0.05 A g−1 in sodium-ion half cells, good rate capability of 53 mAh g−1 at 5 A g−1, and high capacity retention of 92.2% after 1000 cycles at 1 A g−1. Our strategy affords a facile way to prepare high-quality soft carbon materials as anode active materials for sodium-ion batteries. [ABSTRACT FROM AUTHOR]

The concentrate ash content is the most effective evaluation index in the flotation process. However, the ash content obtained by the current technology has a serious hysteresis. In this study, a real-time prediction system based on image processing and BP neural network modeling was established to monitor the flotation process. It will be beneficial to predict the concentrate ash content thereby adjust the flotation conditions opportunely to improve the flotation index. The results show that the predicted values obtained from the BP neural network model established in this study agree well with the actual value. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to quantitatively measure the vulnerability level of the whole rural social-ecological system in Yunnan Province and to analyze the spatial differences of the vulnerability in different regions. Design/methodology/approach: Based on the "exposure-sensitivity-adaptability" vulnerability assessment framework, this paper establishes the index system of rural social-ecological system vulnerability to climate change. Combined with the questionnaire survey and meteorological data, the entropy method was used to measure and analyze the vulnerability level and influencing factors of the overall rural social-ecological system in Yunnan Province. At the same time, the vulnerability level of social-ecological system in Yunnan Province is divided into five levels, and the spatial differences of vulnerability level of 16 states (cities) in Yunnan Province are analyzed. Findings: The results show that: the social-ecological system has high exposure to climate change (0.809), strong sensitivity (0.729), moderate adaptability (0.297) and overall system vulnerability is at a medium level (0.373). Yunnan Province is divided into five levels of social-ecological system vulnerable areas. The areas of extreme, severe, moderate, mild and slight vulnerability account for 21.45%, 24.65%, 36.82%, 13.18% and 3.90% of the whole province, respectively. The geographical division and vulnerability division of Yunnan Province are basically consistent in space. Originality/value: Comprehensive evaluation of the vulnerability of the social-ecological system of Yunnan Province to climate change is the scientific basis for the country to formulate countermeasures against climate change, and it is also the need to improve the adaptability of the social and economic system of the fragile area, reduce the vulnerability and realize the sustainable development of national social economy. The research results can provide a basis for decision-making of climate adaptation in Yunnan and other regions and provide methods and indicators for the assessment of social-ecological system vulnerability under the background of climate change. [ABSTRACT FROM AUTHOR]

In order to study the application of differential privacy data release for the data platform of precise poverty alleviation (PPA), in this study, the data was protected by using differential privacy protection algorithm, and combined with artificial neural network to construct the algorithm model. And then based on MATLAB simulation experiment, the operation effect of the simulation model was verified through multiple angles. From the relationship between budget and coefficient, it can be concluded that compared with extraction procedure and noprivacy by statistical test, the algorithm proposed in this study was found to be more practical, and the result was close to the original data, and the effect was better; the error rate was also the lowest, not higher than 0.075. Comparing the accuracy of the algorithm with other algorithms, the result showed that other methods made the precision lower, but the function mechanism designed in this study did not; from the perspective of time, it is found that the time consumption of algorithm designed in this study was greatly reduced compared with other methods. Through the research in this paper, the model designed by combining artificial neural network and differential privacy achieved the expected effect. Although there are some shortcomings in the experimental process, in general, it can provide direction and guidance for the subsequent PPA work, and its social development has important guiding significance. [ABSTRACT FROM AUTHOR]

Background: To assess the impact of lymph node dissection (LND) extent on overall survival (OS) and cancer-specific survival (CSS) in patients with pN0M0 renal cell carcinoma (RCC) treated with radical nephrectomy (RN). Materials and methods: Data queried for this study include RCC (2010–2014) from the Surveillance, Epidemiology, and End Results (SEER) program. Kaplan–Meier analyses and multivariate Cox regression models tested the effect of number of removed lymph node (NRN) ≥ 50th percentile on OS and CSS. The associations were evaluated using propensity score (PS) matching adjustment. Results: A total of 5532 pN0M0 RCC patients were enrolled in our study. The median NRN was 2 (IQR 1–6), the 50th percentile defined patients with NRN ≥ 2. Following PS adjustment, there were no significant differences in clinicopathologic features between two groups of patients except for age. Multivariate model analysis showed that patients with NRN < 2 had worse OS than those with NRN ≥ 2 in pT3 group (HR 1.442; P = 0.032) but not in pT1 and pT2 groups (HR 0.859 and 1.393, P = 0.443 and P = 0.267, respectively). However, patients with NRN < 2 had better CCS than those with NRN ≥ 2 in pT1 group (HR 0.368; P = 0.016) but not in pT2 and pT3 groups (HR 1.674 and 1.325, P = 0.216 and P = 0.176, respectively). Conclusions: More extensive LND (NRN ≥ 2) at RN is associated with better OS in pT3N0M0 RCC patients while it exerts negative influence on CCS in pT1N0M0 group. Hence, more extensive LND has therapeutic value in pT3 individuals but not in pT1 group. [ABSTRACT FROM AUTHOR]