The effect of particle breakage mechanisms during regrinding on the subsequent cleaner flotation

Stirred mills have been widely used for regrinding, and are acknowledged to be more energy efficient than tumbling mills. These two types of mills present different particle breakage mechanisms during grinding. In this study, the effect of regrinding by both mills on surface properties and subsequent mineral flotation was studied, using chalcocite as the mineral example. A rod mill and a stirred mill with the same stainless steel media were used to regrind rougher flotation concentrates. Different chalcocite flotation recovery was achieved in the cleaner stage after regrinding in tumbling and stirred mills. The factors contributing to the different recovery included particle size, the amount of created fresh surfaces, surface oxidation and the redistribution of collector carried from rougher flotation. All the factors were examined. It was determined that the predominating factor was the different distribution of collector resulting from different particle breakage mechanisms in the stirred and tumbling mills, in line with ToF-SIMS analysis. In the tumbling mill, the impact particle breakage mechanism predominates, causing the collector to remain on the surface of newly produced particles. In the stirred mill, the attrition breakage removes collector from the surface, and decreases particle floatability. Furthermore, the type of grinding media in the stirred mill also influences the subsequent flotation, again due to the change of particle breakage mechanisms. The results of this study demonstrate that the selection of regrinding mills and grinding media should not only depend on the required energy efficiency, but also on the properties of the surfaces produced for subsequent flotation.     

Linear friction welding of Ti–5Al–2Sn–2Zr–4Mo–4Cr alloy with dissimilar microstructure

Dissimilar linear friction welding of Ti–5Al–2Sn–2Zr–4Mo–4Cr with bimodal and lamellar microstructures was produced. The microstructure evolution of the joint was investigated via OM, SEM, XRD, TEM and microhardness analysis. The temperature field of joint was calculated by a numerical model. The typical microstructures of weld center were recrystallized β grains with some acicular α′′ martensites. In the case of thermo-mechanically affected zone, some partial re-crystallization grains formed in severely deformed microstructures, where a mass of dislocations were observed. However, dislocations were rarely found in the recrystallized β grains of weld center, the temperature field of weld joints calculated was consistent with the microstructural evolution.     

Long Non-Coding RNAs: Critical Players in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a complex disease with multiple underlying pathogenic mechanisms caused by a variety of etiologic factors. Emerging evidence showed that long non-coding RNAs (lncRNAs), with size larger than 200 nucleotides (nt), play important roles in various types of cancer development and progression. In recent years, some dysregulated lncRNAs in HCC have been revealed and roles for several of them in HCC have been characterized. All these findings point to the potential of lncRNAs as prospective novel therapeutic targets in HCC. In this review, we summarize known dysregulated lncRNAs in HCC, and review potential biological roles and underlying molecular mechanisms of lncRNAs in HCC. Additionally, we discussed prospects of lncRNAs as potential biomarker and therapeutic target for HCC. In conclusion, this paper will help us gain better understanding of molecular mechanisms by which lncRNAs perform their function in HCC and also provide general strategies and directions for future research.     

Synthesis of lanthanum ricinoleate and its effect on thermal stability and mechanical properties in PVC

The lanthanum ricinoleate（abbreviated as Lari3） of rare earth heat stabilizer was synthesized by the reaction of ricinoleic acid, lanthanum nitrate and sodium hydroxide. The IR and fluorescence spectra methods confirmed the structure of the product. The thermal stability of PVC in the presence of Lari3 was studied by the Congo method and using TG analysis. The results showed that Lari3 could be used as a thermal stabilizer for PVC. When the ratio of Lari3/pentaerythritol was 3：1, the complex exhibited better synergistic effect. Incorporation of Lari3 to PVC resulted in a marked increase of maximum and onset degradation temperature as well as elongation and impact strength of PVC. Lari3 might replace the labile chlorine atoms to interrupt the formation of conjugated double bonds in PVC chains and act as HCl scavenger to restrain the self-catalyticdehydrochlorination.     

堆垛机组导向装置的优化设计

堆垛机组导向装置的优化设计经导柱式导向装置、早期连杆式导向装置、新型连杆式导向装置三个过程，通过不断的技术改进，产品得到逐步完善。本文从优化设计角度，分析原有结构的不足，推出导向装置的新型结构形式并提高了堆垛机组导向装置的动力臂幅度，使机组动作更加灵活、可靠。     

河北省职业教育集团化办学整体发展现状及发展策略研究

通过对于河北省职教集团化发展的现状分析,发现了当前河北省职教集团化发展过程中存在的阻碍职教集团化进一步发展的典型问题,提出了具有较强可操作性、针对性强的河北省职教集团化发展策略,对于政府,教育研究人员,职业院校管理人员有较强的借鉴意义。     

地质水泥对U(Ⅵ)的吸附行为及其机理研究

针对具有放射性的含铀废液，本实验采用间歇法，选用养护28 d、粒径为200~220 μm的地质水泥颗粒作为吸附剂，通过改变水泥投加量、吸附时间、pH值、U(Ⅵ)浓度、溶液温度等环境因素，研究地质水泥对U(Ⅵ)的静态吸附规律，为评估含U(Ⅵ)地质水泥固化体的固有稳定性提供依据。结果表明，在较低固液比（0.5 g/L）和较短时间（1.5 d）内，地质水泥对不同浓度U(Ⅵ)的吸附率达99.9%以上，且吸附量受U(Ⅵ)浓度和环境因素（pH值、溶液温度）的影响较小，吸附条件温和。热力学行为更符合Langmuir等温吸附模型，意味着该过程是一个吸热、以单层吸附为主的吸附过程。吸附材料结构表征结果证实，该吸附过程同时存在物理（静电吸引）与化学（离子交换）两种吸附机制。     

核电厂内部水淹概率风险分析

福岛核事故后，外部灾害事件对核电厂安全的影响逐渐受到重视，而核电厂内部水淹是常见的一种重要灾害，可能导致核电厂发生严重事故，通常无法通过外部事件筛选分析筛除，需对此进行定量评估。本文在对核电厂水淹概率风险分析方法进行了大量研究的基础上，探讨了发生水淹对核电厂设计和运行的影响，提出了内部水淹风险的贡献项。结果表明：电气厂房和设备冷却水系统分别是对内部水淹导致的堆芯损坏频率贡献最大的厂房和水淹源，需在相关区域适当增加水淹防护措施并加强水淹探测及报警能力。