Measurements of keV-neutron capture cross sections and capture gamma-ray spectra of 105Pd

The neutron capture cross sections and capture gamma-ray spectra of ¹⁰⁵Pd were measured in the region from 15 to 100 keV and at 585 keV. A neutron time-of-flight method was utilised with an anti-Compton NaI(Tl) spectrometer and a 1.5-ns pulsed neutron source by the ⁷Li(p,n)⁷Be reaction. The capture yields were obtained by applying a pulse-height weighting technique to the observed net capture gamma-ray pulse-height spectra. The capture cross sections of ¹⁰⁵Pd were derived with errors less than 5%, using the standard capture cross sections of ¹⁹⁷Au. The evaluated capture cross sections of JENDL-4.0 and ENDF/B-VII.1 were compared with the present results. The evaluations of JENDL-4.0 and ENDF/B-VII.1 were larger than the present results by 3%–15% in the region from 15 to 100 keV and at 585 keV. The capture gamma-ray spectra of ¹⁰⁵Pd were also derived by unfolding the observed net capture gamma-ray pulse-height spectra. The multiplicities of capture gamma rays of ¹⁰⁵Pd were obtained from the capture gamma-ray spectra.     

核电厂运行现场高能γ射线的剂量调查

在核电厂正常运行期间,反应堆冷却剂系统内存在能够发射高能γ射线的¹⁶N等放射性核素。为了初步掌握核电厂运行期间不同区域内高能γ射线的辐射水平,利用NaI(Tl)谱仪在国内某核电站测量了反应堆厂房内的γ能谱,并根据γ测量谱和测量系统的响应函数计算了能量大于3 MeV的γ射线的场所剂量率。结果显示:在15个测量位置中,6个位置的γ测量谱中存在明显的高能成分,其对应的剂量率在1.02～30.14 μSv/h范围内。     

直读光谱仪在能力验证中的应用

低合金钢中五大元素的测定是实验室的常规检测项目,通常采用经典的化学分析方法,本文通过对直读光谱仪参加实验室低合金钢中常规检测项目的测试能力验证,结果令人满意。     

An integrated assembly method of sandwich structured ceramic matrix composites

Sandwich structured composites have been widely studied and applied at ambient temperature in aeronautical, automobile and naval applications. For high temperature applications, an integrated ceramic sandwich structure could take advantage of multiple functions such as skin stiffness and core insulation. For thermo-structural applications, skins must be made of ceramic matrix composites (CMC) because of their strength, their resistance to high temperatures (beyond 1000 °C), and their low densities. Concerning foam cores, some carbides (e.g. SiC) are, for their outstanding thermo-mechanical properties, the most appropriate. These foams can withstand long oxidative exposing conditions with low material degradation. This paper presents an assembly method of SiC based sandwich structured CMC. It is performed during sandwich manufacturing in an integrated fashion and allows the production of complex shapes at low costs. Produced flat sandwich panels, characterized by three point bending tests, showed a marked toughening behaviour.     

粉状化妆品中石棉的检测方法

采用x射线衍射（XRD）、偏光显微镜（PLM）和扫描电镜一能谱（SEM—EDS）系统多种分析手段来检测粉状化妆品中的石棉。该方法可以有效避免滑石粉中掺杂其它矿石成分的干扰,能够克服单独使用某一种检测手段的不足及片面性,以实现更快速、更准确的鉴定粉类化妆品中微量石棉及种类。     

Enhanced lithium storage performance of silicon anode via fabricating into sandwich electrode

Silicon electrode with sandwich structure as anode of lithium ion batteries is fabricated by adding a carbon layer between current collector and active coating. The prepared silicon electrode with the sandwich structure can exhibit high reversible capacity of 2500 mAh g⁻¹ for 30 cycles, which is much higher than that of bare silicon electrode with normal structure. The electrochemical impedance spectroscopy and electrode morphologies characterizations show that the improved performance of sandwich electrode is attributed to the carbon layer, which not only enhances the electric conductivity at the current collector/active coating interface but also releases the rigid stress caused by volume change of silicon. The results demonstrate that such sandwich structure is a potential facile method for performance improvement of silicon-based anode compared with the previous reports.     

Elemental composition analysis of superconducting Hg_(0.67)Pb_(0.34)Ba_2Ca_2Cu_3O_(8+δ)

The analysis of superconducting sample by using a sputtered neutral particle mass spectrometer demonstrates that Ca and Ba elements are oxidative, Cu is non-oxidative, Hg is mainly in metallic form near the surface and becomes oxidative far from the surface, and Pb is concentrated on the surface. The analysis also reveals that the highly concentrative hydrocarbon and water impurities are mixed into the sample during the preparation and conservation.     

Improving room-temperature electrochemical performance of solid-state lithium battery by using electrospun La2Zr2O7 fibers-filled composite solid electrolyte

Low ionic conductivity at room temperature and poor interfacial compatibility are the main obstacles to restrain the practical application of polymer solid electrolytes. In this work, lanthanum zirconate (LZO) fibers were prepared by electrospinning method and used for the first time as fillers in sandwich polypropylene carbonate (PPC)-based solid electrolyte. Meanwhile, a graphite coating was applied on one surface of the composite solid electrolyte (CSE) membrane. The results show that the LZO fibers significantly increases the room-temperature electrochemical performance of the CSE, and the graphite coating enhances the interfacial compatibility between electrolyte and lithium anode. Furthermore, an ultra-thin PPC-LZO CSE with a total thickness of 22 μm was prepared and used in NCM622/CSE/Li solid-state cell, which shows an initial discharge capacity of 165.6 mAh/g at the current density of 0.5C and a remaining capacity of 113.0 mAh/g after 250 cycles at room temperature. Rise to 1C, the cell shows an initial discharge capacity of 154.2 mAh/g with a remaining capacity of 95.6 mAh/g after 250 cycles. This ultra-thin CSE is expected to be widely applied in high energy-density solid-state battery with excellent room-temperature electrochemical performances.     

GCr15钢中碳元素含量分析方法探讨

利用红外光谱分析法和光电直读光谱分析法,对10个不同厂家生产的轴承进行碳元素含量的测定进行对比,并根据两种分析方法的原理,结合轴承钢标准中规定的碳含量定义,得出在测定GCr15钢中碳元素含量时,应采用红外光谱分析法测定值。     

夹芯共注成型技术在卫浴行业的应用

卫浴制品生产行业需消耗大量优质塑料原料,而多层制品结构固有的缺点并不适合于卫浴制品.通过对央芯共注成形原理及特性的分析,在马桶盖产品的设计及制造中使用央芯共注成型技术,夹芯共注成型产品中二次料质量约占总质量的40％,节约大量优质塑料.文中指出卫浴等其它优质塑料消耗量大的行业,采用央芯共注成型技术,可大量利用生产过程中产生二次料和回收塑料,降低产品制造成本.