Effect of Long-Term Forest Fertilization on Scots Pine Xylem Quality and Wood Borer Performance

We tested whether changes in long-term nutrient availability would affect the xylem quality and characteristics of Scots pine trees as a food source for the larvae of the xylophagous wood borer Hylotrupes bajulus L. (Cerambycidae). We looked for an effect of host plant growth and xylem structural traits on H. bajulus larval performance, and looked for delayed effects of long-term forest fertilization on xylem chemical quality. In general, larval performance was dependent on larval developmental stage. However, the growth of larvae also varied with host plant quality (increases in the concentration of nitrogen and carbon-based secondary compounds of xylem were correlated with a decrease in the larval growth rate). The greater annual growth of trees reduced tracheid length and correlated positively with second-instar H. bajulus growth rate. This is consistent with the hypothesis that intrinsic growth patterns of host plants influence the development of the xylophagous wood borer H. bajulus.     

DGJW40钢结硬质合金淬火与回火的研究

DGJW40是一种新型的钢结硬质合金,对其进行了淬火与回火试验。结果表明：淬火加热时,该合金的过热敏感性小,硬度随淬火温度的升高而提高;回火稳定性较好,在450℃附近出现“二次硬化峰”,未出现明显的“回火脆性”。     

The effect of the interlayer anions on the electrochemical performance of layered double hydroxide electrode materials

Both high energy density and high power density are vitally required for new applications such as electric vehicles. Here we present a comparison of two well-crystallised layered double hydroxides, [Ni₄Al(OH)₁₀]OH and [Ni₄Al(OH)₁₀]NO₃, which shows that the former can maintain a better discharge capacity, 294-299 mAh g⁻¹, than the latter, 233-287 mAh g⁻¹ at a current density of 2000 mA g⁻¹ within about 300 cycles, although both electrodes deliver a similar capacity of 326 mAh g⁻¹ at 200 mA g⁻¹ initially. It is believed that both the more watery interlayer space in [Ni₄Al(OH)₁₀]OH than in [Ni₄Al(OH)₁₀]NO₃ and the morphologic changes induced by anion exchange of NO₃⁻ by OH⁻ during electrochemical cycles play key roles in their behaviour.     

High-Temperature Plasticity Enhanced by Multiple Secondary Phases in a High-Si Austenitic Stainless Steel

An austenitic stainless steel with 6 wt% Si and multiple secondary phases was produced with the aim to achieve enhanced plasticity during hot deformation. The microstructure of the steel after fracture was characterized via electron back-scattered diffraction, transmission Kikuchi diffraction and scanning transmission electron microscopy. From the tail of the gage to the necking region, the microstructure of the material evolved from low-angle grain boundaries (LAGBs) to mixtures of LAGBs and high-angle grain boundaries (HAGBs), and fine equiaxed recrystallized grains. The elongation to failure in the tensile test exceeds 167%. During the hot deformation, continuous dynamic recrystallization of the austenitic matrix was promoted by the multiple secondary phases. The dislocations introduced by the secondary phases were rearranged and continuously transformed into HAGBs. The initially coarse grains (30.5 μm) were refined into ultra-fine equiaxed grains (1 μm), which contributed significantly the enhanced plasticity during hot deformation of the steel. In the necking area of the sample, twins were nucleated in the stress concentration regions and accommodated the local strain by discontinuous dynamic recrystallization, which was also beneficial to improving the plasticity.     

长岭气田登娄库组成岩作用特征及次生孔隙发育研究

长岭气田位于松辽盆地南部,登娄库组砂岩储层是其主要含气层位。储层的埋深大,成岩作用强,对孔隙发育及孔隙结构影响显著,次生孔隙的发育是登娄库组储层天然气聚集的主要控制因素。研究主要利用薄片鉴定等分析化验数据对登娄库组砂岩储层的成岩作用特征和孔隙结构特征进行研究,并指出登娄库组砂岩储层的次生孔隙发育位置,为气田开发指明了方向。     

脉冲离子束辐照致TiD_2膜力学性能的变化

金属氢化物(MH_x)应用于反应堆中子慢化剂、激光离子源片材料、中子发生器用靶时,会经历极端非平衡束流的辐照。本工作提出利用TEMP-6型强流脉冲离子束装置产生的强流脉冲离子束(high intensity pulsed ion beam,HIPIB)辐照Ti D_2膜,评估极端束流对膜力学性能的影响因素和影响程度。采用涂层附着力自动划痕仪、维氏显微硬度计对原始和辐照后的Ti D_2膜进行测试分析。研究结果发现:多次HIPIB的辐照效应导致膜面重熔再结晶,使其内部结构趋于更加致密化和平整化,能降低材料的摩擦系数并在一定程度上提高其初始临界载荷;D的释放有助于膜面韧性、显微硬度的提高,从而减轻了其塑性形变程度。     

基于PS球的银微米结构制备及二次电子发射性能

金属材料的二次电子发射是空间微波部件发生微放电效应的重要机制,微放电效应是航天器有效载荷射频功率增大的限制因素。本实验通过在金属银表面构造大尺度聚苯乙烯(PS)微球阵列制备微米尺度的银膜陷阱结构,实现对二次电子发射的抑制。重点研究了PS微球自组装方法对自组装效果的影响及镀银方式对银膜陷阱结构形貌的影响,并对利用PS微球构造的银膜陷阱结构的二次电子发射性能进行研究。结果表明:蒸发沉积法中的单基片法可有效实现PS微球的自组装,电化学沉积法镀银可获得银膜陷阱结构,且该银膜陷阱结构的二次电子发射系数最大值从2.2降低至1.6。     

定模推件带活镶块的压铸模

针对铸件矩形深腔底部成型困难和深腔对定模主型芯包紧力大的特点,采用带活镶块定模推件的模具结构.在铸件深腔底部离浇口最远处设置活镶块,其上开有溢流槽,有利于铸件深腔底部成形.推件时活镶块和工件一起推出,取下活镶块.模具设两个分型面,设有可靠的顺序定距分型机构.定模型腔板兼作定模推件板,第1次分型时定模推件板推动铸件先消除对定模主型芯的包紧力,以保证第2次分型时铸件留在动模上.     

方坯连铸机二冷水控制模型与应用

采用拉速、过热度、钢坯温度调节法控制方坯连铸二冷区水量,控制模型避开铸坯表面温度的直接测量,应用方坯凝固传热数学模型进行计算。以生产厂小方坯连铸机为研究对象,比较了采用不同的二冷水控制方法时控制效果的差异。结果表明,当浇注条件稳定时,采用拉速-水量控制方法可获得较稳定的铸坯表面温度分布,在拉速出现波动时,采用钢坯温度进一步调节水量的动态控制法比拉速、过热度-水量控制法有更好的控制效果。     

PLLA/CPC复合支架增强结构设计及制备

为制备用于负重部位骨缺损修复的人工植入体,提出了一种复合增强结构人工骨设计及制备方案,该方案采用聚左旋乳酸支架(PLLA)为增强结构,以自凝固磷酸钙骨水泥(CPC)为复合填充材料,制备了复合增强结构人工骨。研究了PLLA的棒材力学性能、支架设计和制作及其不同增强结构形式对人工骨力学性能的影响。力学试验结果表明,所制作的人工骨有效提高了承载能力,并且该复合结构能有效弥补金属骨无法降解的缺陷。