Large-scale fabrication of Ag nanoparticles in PVP nanofibres and net-like silver nanofibre films by electrospinning

Heat treatment of various compositions of AgNO(3)-doped polyvinylpyrrolidone (PVP) composite nanofibres fabricated by electrospinning produced two kinds of silver species: (i) Ag nanoparticles dispersed in PVP nanofibres, when the loading of AgNO(3) was 5?wt%, and (ii)?a net-like silver nanofibre film when the loading of AgNO(3) was five times greater than that of PVP in the composite nanofibres. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-visible absorption spectroscopy, FT-IR spectra, powder x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) were used to characterize the silver nanoparticles and nanofibres. The formation mechanisms are discussed based on the redox reaction between AgNO(3) and PVP during heat treatment; essentially, the weight ratios of AgNO(3) to PVP determined the types of morphologies, from Ag nanoparticles to silver nanofibre film. The present results may find some potential application in the design of new composite materials in the dielectric and electronics areas.     

中国2019年黄金物质流分析

党的“十九大”提出中国经济正由高速增长阶段转向高质量发展阶段,这标志着我国黄金行业也必须从过去只重视规模速度的粗放型发展方式向注重质量效益的集约型发展方式转变。为了更好地了解中国黄金行业的发展现状,探究黄金在社会经济系统中的代谢过程,本文运用物质流分析方法,依据文献调研和统计数据,通过搭建黄金物质流框架,以2019年为例探讨我国黄金物质流的实现路径,对物质流中生产、加工制造、使用、废弃物管理4个阶段展开具体分析。研究结果表明：1）生产阶段向加工制造阶段流入精炼金1 015 t,金矿尾渣排放损耗黄金900 t。在此阶段,金矿资源的严重消耗与环境污染加剧问题对我国黄金产业的可持续发展产生了不利影响。2）加工制造阶段的进口纯金量为781 t,向使用阶段流入精炼金1 706 t,黄金损耗为90 t。2019年我国黄金供给对外依存度达到52.5%,显示出整体偏高的态势。3）在使用阶段,2019年我国黄金需求总量为1 641 t,其中黄金消费量为1 003 t,黄金消费以金饰为主,占该年黄金消费量的67.4%。4）在废弃物管理阶段,2019年我国回收黄金量为465 t,占该年黄金供应量的27%。研究结论：1）我国黄金生产以矿产金为主、有色冶炼副产金为辅,其中有色副产金占黄金总产量的比例从2000年的9%增长到2019年的16%,表明我国黄金产业的集约化程度正在逐步提高。2）我国对黄金资源需求量巨大,黄金资源对外依存度较高。近些年我国工业领域的黄金消费量增长很快,未来随着电子产业的快速发展还会不断扩大对黄金资源的需求。3）回收黄金是我国黄金资源供应的重要组成部分,其中黄金饰品的回收收益比工业回收高出很多,工业黄金回收工艺还有待进一步提高,产业链还有待进一步完善。     

微电网黑启动研究综述

随着分布式电源技术的不断提升,微电网得到了快速的发展。为保证微电网的持续稳定运行,同时为大电网的恢复提供黑启动电源,微电网在孤岛运行状态下应具备快速黑启动能力。从微电网黑启动电源的选择和控制方法、微电网黑启动策略和微电网黑启动过程中存在的主要问题及相关措施等方面介绍了国内外在微电网黑启动方面的研究,为今后的微电网黑启动研究及其应用提供参考。     

大锻件喷淬节能控制系统的设计及应用

针对目前很多大型铸锻件淬火冷却设备采用恒流量喷水工艺,水、电消耗量大的实际情况,采用水量递减喷淬优化工艺,设计出大锻件喷淬节能控制系统。经过试验验证,该大锻件喷淬节能控制系统运行稳定,节水32.4%,节电53.3%。     

渝东南下寒武统页岩储层特征及测井评价——以渝科1井和酉科1井为例

为了正确认识渝东南地区下寒武统牛蹄塘组黑色页岩储层特征与主控因素,对采自渝科1井和酉科1井的岩心样品,进行了系统的黏土矿物及全岩X-射线衍射分析、岩石常规物性分析、比表面和孔径分析、岩石有机碳分析、镜质体反射率（R_o）及显微组分测试。测试分析结果表明：牛蹄塘组页岩储层碎屑矿物含量平均为51.34%,黏土矿物含量平均为32.74%,有效孔隙度平均为1.2%,渗透率平均为8.0×10^-3mD,属于特低孔、特低渗储层。孔隙以中孔为主,约占总孔体积的73% 。BET（Brunauer、Emmett和Teller）比表面积平均为7.75 m²/g,平均孔直径为5.3 nm。总有机碳含量（TOC）平均为2.29%,R_o平均为3.12%,属于过成熟阶段。进一步统计分析表明：TOC与微孔体积呈正相关,黏土矿物总量与之呈负相关;TOC、黏土矿物总量、碳酸盐矿物含量均与中孔体积呈正相关;TOC、碳酸盐矿物含量均与宏孔体积呈正相关,碎屑矿物含量与之呈弱的正相关,黏土矿物总量与之呈负相关。用常规测井方法对牛蹄塘组页岩的孔隙度和TOC进行了计算,发现利用中子曲线计算的孔隙度与岩心分析结果在两口井中均吻合较好,但浅层不含油气情况下,自然伽马曲线（GR）与岩心分析TOC之间无明显相关关系。     

基于经验模态分解和支持向量机的水电机组振动故障诊断

水电机组的振动信号为典型的非平稳、非线性信号。为了通过振动信号正确判断水电机组的运行状态,本文提出运用经验模态分解处理原始信号,并对获得的基本模式分量计算其复杂度特征,最后运用最小二乘支持向量机进行故障诊断。选取径向基函数作为核函数,并通过网格搜索和交叉验证确定相关参数。结果表明,经验模态分解复杂度特征和支持向量机结合,能够准确地实现故障诊断,确定故障类型,为机组运行维护人员提供参考依据。     

Ferroptosis Mechanisms Involved in Hippocampal-Related Diseases

Ferroptosis is a newly recognized type of cell death that is different from traditional forms of cell death, such as apoptosis, autophagy, and necrosis. It is caused by the accumulation of intracellular iron, promoting lipid peroxidation and leading to cell death. Iron is essential as a redox metal in several physiological functions. The brain is one of the organs known to be affected by iron homeostatic balance disruption. An increased concentration of iron in the central nervous system has been associated with oxidative stress, lipid peroxidation of proteins, and cell death. The hippocampus is an important brain region for learning, memory, and emotional responses, and is also a sensitive part of the brain to the dysfunctional homeostasis of transition metals. Damage of hippocampal structure and function are intimately involved in the pathogenic mechanisms underlying neurodegenerative diseases. Currently, ferroptosis is playing an increasingly important role in treatment areas of central nervous system diseases. Thus, we provide an overview of ferroptosis regulatory mechanisms, such as lipid metabolism, glutathione metabolism, and iron metabolism in this review. We also highlight the role of ferroptosis in hippocampal-related diseases and investigate a theoretical basis for further research on the role of ferroptosis in nervous system disease treatment.     

两室气体互通对光合微生物燃料电池性能的影响

以斜生栅藻生长产生氧为电子受体的光合微生物燃料电池(PMFC)和外加CO2光合微生物燃料电池(AC-PMFC)联合构建成微生物碳捕获电池(MCC)。研究MCC在不同运行条件下的产电性能及影响因素。测量MCC, PMFC和AC-PMFC三种系统中的电压、溶解氧和pH。结果表明,产电压趋势与所有系统中的藻类阴极的氧浓度相关,电解液pH也能影响MFC电压的产生。三种类型的MFC中,MCC产电性能最佳,其电压和功率密度分别可达492 mV和102.3 mW/m2,最大功率密度分别比PMFC和AC-PMFC高42.33%, 54.08%。AC-PMFC由于添加了相对高浓度的CO2,抑制了微藻的生物活性和光合作用,产生的电压和功率密度最低。用SEM观察长期运行后的MCC的阴极表面藻类的形貌特征,藻生物膜与电极板表面能够生成一层高浓度的原位氧膜。电化学分析表明斜生栅藻–生物膜本身不能直接接收来自极板上的电子,无生物催化活性。但这层膜可促进O2的还原速率且可有效降低电池内阻。PCR和16S rRNA基因检测技术分析结果表明,MFC中的Chao1指数为170,而PMFC为152,MCC为145,阴极中的过饱和氧可通过管道输送到阳极并影响阳极的微生物群落。本研究结果为进一步改善藻类微生物碳捕获电池性能提供基础。     

AMPS/HEMA/AA三元共聚物的合成及其阻垢性能

以2-丙烯酰胺-2-甲基丙磺酸（AMPS）、甲基丙烯酸羟乙酯（HEMA）和丙烯酸（AA）为单体, 过硫酸铵为引发剂,采用水溶液聚合法合成AMPS/HEMA/AA三元共聚物。通过单因素实验,选取静态阻垢 方法测定阻垢率,探讨了合成的三元共聚物投加量、溶液的pH值、硬度（Ca2+质量浓度）、碱度等因素 对共聚物阻垢性能的影响。同时对其适用的水质进行研究,当AMPS/HEMA/AA共聚物质量浓度5 mg/L、 Ca2+质量浓度200 mg/L、HCO3-质量浓度500 mg/L、温度70℃、pH值6、时间10 h时,对CaCO3的阻垢率 达到最高;当AMPS/HEMA/AA 共聚物质量浓度3 mg/L、Ca2+质量浓度2000 mg/L、SO42-质量浓度5000 mg/L、温度45℃、pH值9、时间5 h时,对CaSO4的阻垢率达到最高。通过扫描电镜初步探索了 AMPS/HEMA/AA三元共聚物阻垢作用的机理。本课题的创新点在于合成的AMPS/HEMA/AA共聚物的单体无磷 、无氮,可避免三废排放,是一种性能优异的绿色阻垢剂。     

Grain Size Associated Genes and the Molecular Regulatory Mechanism in Rice

Grain size is a quantitative trait that is controlled by multiple genes. It is not only a yield trait, but also an important appearance quality of rice. In addition, grain size is easy to be selected in evolution, which is also a significant trait for studying rice evolution. In recent years, many quantitative trait loci (QTL)/genes for rice grain size were isolated by map-based cloning or genome-wide association studies, which revealed the genetic and molecular mechanism of grain size regulation in part. Here, we summarized the QTL/genes cloned for grain size and the regulation mechanism with a view to provide the theoretical basis for improving rice yield and breeding superior varieties.