Extraction of metals from complex sulfide nickel concentrates by low-temperature chlorination roasting and water leaching

The recovery of valuable metals from complex sulfide concentrates was investigated via chlorination roasting followed by water leaching. A reaction process is proposed on the basis of previous studies and the results of our preliminary experiments. During the process, various process parameters were studied, including the roasting temperature, the addition of NH₄Cl, the roasting time, the leaching time, and the liquid-to-solid ratio. The roasted products and leach residues were characterized by X-ray diffraction and vibrational spectroscopy. Under the optimum condition, 95% of Ni, 98% of Cu, and 88% of Co were recovered. In addition, the removal of iron was studied in the water leaching stage. The results demonstrate that this process provides an effective approach for extracting multiple metals from complex concentrates or ores.     

氧化石墨烯-铁基复合材料的制备及热稳定性能研究

采用改进的hummers法制备氧化石墨,通过超声震荡剥离成单层的氧化石墨烯.以制备的氧化石墨烯作为原料,水热法合成四氧化三铁/氧化石墨烯复合材料.利用SEM,XRD,Raman对此复合材料物相结构及形貌进行表征,并对样品进行热重-差热分析,获得较优的热稳定性能,从而更好地应用于阻燃领域.     

Cadherin 22 participates in the self-renewal of mouse female germ line stem cells via interaction with JAK2 and β-catenin

The self-renewal capacity of the stem cell pool determines tissue function and health. Cadherin-22 (Cdh22), a member of the cadherin superfamily, has two splicing patterns in rats, and the short type that lacks a catenin binding domain is closely related to spermatogonial stem cell self-renewal. Previously, we reported that CDH22 was highly expressed in mouse ovary germ cells, especially in female germ line stem cells (FGSCs). However, its underlying function in FGSCs is still not clear. Here, we found that Cdh22 encodes only one type of protein product in mice and demonstrated that CDH22 was required for FGSC self-renewal. In addition, JAK2 and β-catenin were found to interact with CDH22 and be involved in CDH22 signaling in mouse FGSCs. Moreover, extrinsic CDH22 was identified as a potential molecule that participates in FGSC adhesion and is pivotal for FGSC maintenance and self-renewal. These results reveal that CDH22 functions as an essential molecule in FGSC maintenance and self-renewal via different mechanisms, including interaction with the JAK-STAT signaling pathway and β-catenin.     

农科类专业实践教学模式探索

实践教学对学生综合素质的提高、创新精神和实践能力的培养具有特殊作用,是提高人才培养质量的有效途径。生产实习是农科类专业实践教学体系中最重要的一环,通过深化对实践教学的认识,修订人才培养方案和制定科学合理的实践教学计划,加大实践教学基地建设力度以及加强生产实习管理,湖北工程学院农学院逐步探索出生产实习与毕业论文、学生就业相结合的实践教学模式。湖北工程学院农学、园艺专业十多年的实践证明,该模式实施效果良好。     

白居易诗中之数字与佛禅思想

唐人在诗中频繁使用数字,成为其时诗文创作的重要表现形式.白居易诗中所出现的数字却常用以记叙现实状况.分析白居易以数字入诗的特点,可以认识白居易的“中人”意识,以及白居易以数字入诗背后所隐含的佛禅思想.     

Typical Construction Program of 600 MV Unit Supercritical Boiler Boiler

文章介绍了国产600 MW机组超临界直流锅炉的施工方案,重点论述了主要施工机械和布置、施工方案简介,前后炉膛的吊装顺序.     

黏土中倾斜螺旋桩的水平承载性能数值模拟及理论研究

为研究黏土中螺旋桩倾斜单桩的水平承载性能,基于非线性有限元软件ABAQUS建立有限元分析模型.通过数值模拟结果与已有螺旋桩软土地基抗拔试验及砂土地基水平承载试验的对比分析,验证了该数值模型的准确性与可行性.探讨了不同倾斜角度下叶片数量和首层叶片埋深对螺旋桩水平承载性能的影响规律.结果 表明:叶片数量对倾斜螺旋桩的水平承载性能影响不大;倾斜角度增大,首层叶片埋深影响逐渐变小,但总体上首层叶片埋深越深,倾斜螺旋桩的水平承载性能越差,当埋深达到4倍叶片直径的深度后,水平承载性能基本不再变化.基于数值模拟结果提出了不同倾斜角度下螺旋桩水平极限承载力计算中锚片所承担部分的计算公式.随着倾斜角度增加,叶片在螺旋桩中的抗倾覆作用逐渐向抗拔作用转变,所提出的水平极限承载力计算公式较为可靠.     

Business Environment and Resource Allocation Based on the Perspective of the National Value Chain

China is actively upgrading its industrial structure through industries transferring between developed and undeveloped areas; however, the overall level of the national value chain is still not high, and the asymmetric competition pattern between the upstream and the downstream has not been broken. Therefore, this paper establishes a competitive equilibrium model for the production of manufacturing enterprises, with factor price distortion, under the condition of constant returns to scale.The au...     

Nano-mechanical and tribological properties of copper matrix composites reinforced by graphene nanosheets

The impacts of graphene nanosheets content on microstructure, nano-mechanical and tribological properties of the copper matrix composites were investigated. The graphene nanosheets randomly distributed in copper matrix, which obviously hindered its grain growth. The elastic modulus and nano-hardness of the copper matrix composite with 0.2 wt% graphene nanosheets were enhanced 47.5% and 54.7% compared to these of pure copper, respectively. The average creep degree(5.1%) was lower than that(11.8%) of pure copper in holding stage. The creep rate(ca. 0.016 nm/s) decreased 10 times as that(ca. 0.16 nm/s) of pure copper in steady-state creep. The tribological performances were improved dramatically with increase of graphene nanosheets content.     

中国海洋鱼类单殖吸虫研究XXIV. 斧形虫科一新记录种

本文记述了采自海南三亚杜氏下鱵Hyporhamphus dussumieri鳃上的1种单殖吸虫低鱵斧形虫Axine depauperati Yamaguti, 1968。所获标本与Yamaguti（1968）的原始描述基本一致，但在吸铗形状、端钩数量、生殖腔刺和阴茎刺数量上略有差异。低鱵斧形虫为中国新记录，杜氏下鱵为宿主新记录。