Study on Zr and Y co-doped BaCeO3 film enhencement of lightning-strike protection equipment

采用溶胶-凝胶法,在铁基底上制备了Zr和Y掺杂的BaCeO3体系涂层薄膜,利用X射线衍射（XRD）、扫描电镜（SEM）和TEM,表征了其晶体结构、表面和断面形貌。XRD分析结果表明,制备的膜层以BaCe0.8Zr0.1Y0.1O3-a相为主;膜层表面SEM表征结果表明,涂层均匀,没有大的裂纹、孔洞等缺陷;膜层与基底断面的TEM表征结果表明,界面处两者匹配较好。在干燥和湿润空气条件下测量膜层材料电导率,湿润空气中膜层材料电导率较高,且温度越高其电导率越高。这种膜层适合作为避雷线的保护层,并能起到增强避雷线性能的作用。     

Microglial Cell Activation Increases Saturated and Decreases Monounsaturated Fatty Acid Content,but Both Lipid Species are Proinflammatory

Neuroinflammation is a component of age-related neurodegenerative diseases and cognitive decline. Saturated (SFA) and monounsaturated (MUFA) fatty acids are bioactive molecules that may play different extrinsic and intrinsic roles in neuroinflammation, serving as exogenous ligands for cellular receptors, or endogenous components of cell structural, energetic and signaling pathways. We determined the fatty acyl profile of BV2 microglial cells before and after acute activation with lipopolysaccharide (LPS). We also investigated the effect of SFA and MUFA pretreatment on the production of an invasive, neurotoxic phenotype in BV2 cells. Acute activation of BV2 microglia resulted in an increase in the relative content of SFA (12:0, 16:0, 18:0, 20:0, 22:0, and 24:0 increased significantly), and a relative decrease in the content of MUFA (16:1n7, 18:1n7, 18:1n9, 20:1n9, 24:1n9 decreased significantly). In agreement, the major stearoyl-CoA desaturase (SCD) isoform in BV2 cells, SCD2, was significantly down-regulated by LPS. We next treated cells with SFA (16:0 or 18:0) or MUFA (16:1n7 or 18:1n9), and found that levels of secreted IL6 were increased, as was secreted MMP9-mediated proteolytic activity. To test the functional significance, we treated SH-SY5Y neuronal cells with conditioned medium from BV2 cells pretreated with fatty acids, and found a small but significant induction of cell death. Our findings suggest differential intrinsic roles for SFA and MUFA in activated microglial cells, but similar extrinsic roles for these fatty acid species in inducing activation. Expansion of SFA is important during microglial cell activation, but either supplemental SFA or MUFA may contribute to chronic low-grade neuroinflammation.     

Y型分子筛的有机酸脱铝改性

利用有机酸对Y型分子筛进行改性,采用XRD、XRF、XPS和IR等对其进行表征,结果表明,分子筛经过离子交换降低钠含量,水热焙烧后,采用有机络合剂进行处理,更有利于得到结晶度高和非骨架铝含量低的分子筛;在相同柠檬酸或草酸比例下,采用柠檬酸处理的样品,其硅铝物质的量比和结晶度均高于草酸处理样品;有机酸处理有利于分子筛非骨架铝的脱除,尤其分子筛外表面非骨架铝的脱除,提高分子筛结晶度和硅铝物质的量比。m(柠檬酸)∶m(分子筛)=a∶1~(a+0.10)∶1时,晶胞尺寸变化不大;m(柠檬酸)∶m(分子筛)=(a+0.15)∶1时,分子筛晶胞进一步收缩,结晶度降低;随着柠檬酸比例增加,脱铝处理分子筛的B/L降低。     

基于63Ni辐伏同位素电池原型封装可靠性研究

以加载有63Ni源片的GD3217Y型探测器为处理件，在完成对封装材料的配方选择、灌注工艺、流程的制定并得到具有较好工艺性的灌注条件的基础上，分别对原件、加载不锈钢圆片器件、加载电镀814×107Bq63Ni不锈钢圆片器件进行非放、放射灌注封装。在对灌件可靠性进行检测的基础上，着重考察了原件、无/加载不锈钢圆片灌件、加载电镀814×107Bq63Ni不锈钢圆片灌件封装前后、自然老化及人工加速老化后电学输出特性，即考察在63Ni源持续辐照下，灌料、63Ni源、不锈钢片、芯片以及其他部件构成的体系内部之间相互作用关系，即封装件特殊要求——屏蔽性、时效性。研究结果表明，对以上结构的GD3217Y型探测器组件采用该种封装方式后除改善探测器组件的环境适应性，特别是在保证放射源使用安全性的基础上具有较为稳定的电学输出性能，这为辐伏效应同位素电池封装提供了参考。     

Microstructural evolution in silicon alloyed γ-Ti–Al alloys after thermomechanical processing

Abstract

The microstructures of silicon alloyed γ-Ti–Al alloys containing silicide particles have been studied after thermomechanical treatments to investigate microstructural evolution. Important parameters including temperature, forging strain, and sequence of thermomechanical treatments were systematically studied. Isothermal forging below the eutectoid temperature resulted in inhomogeneous dynamic recrystallisation with fine equiaxed grains in recrystallised areas and residual α₂ + γ lamellae elsewhere. Eutectic silicides play an important role in destruction of the as cast structure by promoting dynamic recrystallisation during deformation and static recrystallisation on subsequent annealing. There is evidence that silicon, in solution, also enhances recrystallisation. The presence of fine silicides produced by precipitation in the solid state restricts the size of grains produced by both dynamic and static recrystallisation. Silicon also alters significantly the phase equilibrium between the α and γ phases.     

相变温度附近等温热处理对Mg97Zn1Y2合金组织演化的影响

研究了相变温度附近等温热处理温度和保温时间对含长周期结构Mg97Zn1Y2合金的组织的影响，并对演变机理进行了探讨。主要研究结论如下：500℃固溶处理时，随着时间的增加，长周期结构有增长的趋势。采用等温热处理可以将Mg97Zn1Y2合金中的枝晶组织转变为球状晶，当合金保温温度范围从540℃~600℃时，组织尺寸由大-小-大的顺序变化，即经过了粗化、分离及球化至最后粗化三个过程。在等温热处理温度为575℃的组织大致演变趋势为：枝晶态-不规则球形+块状-球形状，当保温时间15min，其组织为均匀、圆整的球状晶。     

Performance analysis of a k‐nearest neighbor searching technique

Abstract

A transfer admittance is treated as a two‐terminal network driven by cascaded dependent sources. By complex‐curve fitting, each of the four admittances of a conventional two‐port model can be approximated over a wideband with a rational function of frequency. A SPICE2‐acceptable R‐L‐C two‐port model can then be derived by applying continued fractions to the rational functions. Examples are included to demonstrate the applications of this method.     

Effects of Zn and Y on hot-tearing susceptibility of Mg–xZn–2xY alloys

The effect of Zn and Y on hot-tearing susceptibility (HTS) of Mg–xZn–2xY (x?=?1, 1.67, 2.67) alloys is investigated. It is found that the microstructure of the alloys is mainly composed of α-Mg, long-period stacking-ordered (LPSO) phase and W-phase. Both theoretical and experimental results illustrated that HTS of the investigated alloys is in the following order: Mg–1Zn–2Y > Mg–1.67Zn–3.34Y > Mg–2.67Zn–5.34Y. For Mg–2.67Zn–5.34Y alloy, LPSO phase content reaches at the maximum and its grain size reaches at minimum of 16.4 µm, and the pinning effect of the LPSO phase on grain boundaries is considered to be an important reason for reducing HTS of the alloy.     

金属正电子核素~(64)Cu,~(68)Ga,~(86)Y和~(89)Zr的PET标记药物研究进展

~(64)Cu,~(68)Ga,~(86)Y和~(89)Zr具备不同的半衰期和特殊生物体内性质,丰富了PET药物的多样性,为疾病的诊断和治疗提供了新的契机。近年来,金属正电子核素~(64)Cu,~(68)Ga,~(86)Y和~(89)Zr标记的药物在正电子发射计算机断层显像(PET)诊断中的应用越来越多,~(64)Cu在乏氧显像中发挥重要作用,~(68)Ga在靶向神经内分泌(NET)类肿瘤的诊断药物领域发展迅速,~(86)Y,~(89)Zr有望在免疫PET和放射免疫治疗领域发挥作用。本文主要综述金属正电子核素~(64)Cu,~(68)Ga,~(86)Y,~(89)Zr的生产与纯化,溶液配位化学以及应用方面的研究进展。