地球模拟器中热地球温度分析

提出了地球光阑与热地球分别放置在不同机械支撑结构上的新型低轨道地球模拟器,该地球模拟器省去了地球光阑的制冷装置,简化了地球模拟器的结构。本文对这种地球模拟器的主要部件--热地球的辐射与温度的关系进行了理论分析,确定了热地球辐射面板需要达到的温度范围及辐射表面的均匀度范围,同时设计了热地球的具体结构。     

Microstructure, solderability, and growth of intermetallic compounds of Sn-Ag-Cu-RE lead-free solder alloys

The near-eutectic Sn-3.5 wt.% Ag-0.7 wt.% Cu (Sn-3.5Ag-0.7Cu) alloy was doped with rare earth (RE) elements of primarily Ce and La of 0.05–0.25 wt.% to form Sn-3.5Ag-0.7Cu-xRE solder alloys. The aim of this research was to investigate the effect of the addition of RE elements on the microstructure and solderability of this alloy. Sn-3.5Ag-0.7Cu-xRE solders were soldered on copper coupons. The thickness of the intermetallic layer (IML) formed between the solder and Cu substrate just after soldering, as well as after thermal aging at 170°C up to 1000 h, was investigated. It was found that, due to the addition of the RE elements, the size of the Sn grains was reduced. In particular, the addition of 0.1wt.%RE to the Sn-3.5Ag-0.7Cu solder improved the wetting behavior. Besides, the IML growth during thermal aging was inhibited.     

纳米非晶态Ni(OH)_2电极材料的稀土掺杂改性研究

为了提高镍基二次电池正极材料的电化学性能,采用微乳液快速冷冻沉淀法制备出稀土Ce掺杂纳米级非晶态氢氧化镍粉体材料.采用Raman,XRD,SEM和TEM对其结构形态进行了表征分析,采用交流阻抗谱(EIS)和充放电性能对其电化学性能进行了测试.结果发现,掺入适量的Ce可以进一步增强纳米非晶态氢氧化镍的无序性并且使颗粒细化,进而使其电化学反应的电荷转移电阻降低,电化学活性明显增强.样品作为MH-Ni电池正极材料以0.2 C充放电,终止电压为1.0 V,当掺杂Ce的质量分数为4%时,其放电比容量达到336.7 mAh/g,这明显高于晶态β-氢氧化镍电极材料289 mAh/g的理论容量,说明纳米非晶态氢氧化镍作为高活性电极材料具有很好的应用前景.     

Simultaneous Activation of Short‐Wave Infrared (SWIR) Light and Paramagnetism by a Functionalized Shell for High Penetration and Spatial Resolution Theranostics

Nanoparticle emitting short‐wave infrared (SWIR) light has received increased attention in the molecular imaging field due to its deeper tissue penetration, fast imaging, high sensitivity, and resolution. The simultaneously activated SWIR excited directly by an 808 nm laser and T₁‐weighted magnetic resonance imaging (MRI) signal are found in one single‐shell nanoparticle NaErF₄@NaGdF₄ (Er@Gd), which is used as a dual‐modality imaging contrast agent in vivo to accurately determine the position of tumors. The conjugated cypate is then aggregated on the surface of Er@Gd@SiO₂‐Cy/bovine serum albumin. With the guidance of dual modality imaging, photothermal therapy is effectively used to ablate tumors in a mouse model. The design of single‐shell nanomaterial activation of SWIR imaging and MRI signals is expected to provide a new strategy for high penetration and spatial resolution cancer theranostics.     

Yb3+/Er3+共掺ZnF2粉末上转换发光特性研究

为了研究ZnF₂作为基质材料、稀土离子Yb3+和Er3+共掺摩尔分数不同时的发光性能,采用高温固相法,在820℃时制备稀土掺杂ZnF₂样品,并对各个样品进行上转换发射光谱测试。将激发功率与上转换发射功率进行曲线拟合,确定Yb3+和Er3+光子吸收过程。结果表明,在980nm半导体激光器激发下,样品在可见光区域内存在533nm,555nm和655nm 3个上转换发射峰,发射的红光强度大于绿光强度,吸收光子数目依次为1.73,1.75,1.88,确定3个发射峰均对应于双光子吸收。此研究说明稀土离子掺杂ZnF₂材料将在上转换红色荧光粉领域有重要的应用前景。     

龙潭水电站抛物线双曲拱坝体形设计

龙潭水电站大坝采用砼新型抛物线双曲拱坝，文章对坝体体形设计作了详细论述在坝体设计中，坝体结构得到优化，拱坝结构的特点得以充分发挥     

三峡泄洪2￣#坝段位移场的确定性时空分布模型

应用线弹性、粘弹性有限元数值计算方法，以空间多个测点的观测资料为依据，引入测点坐标建立三峡泄洪２＃坝段空间位移场的确定性模型。该模型可以动态监测泄洪２＃坝段在任一组荷载下的位移场，以此分析和评价大坝变形性态。     

双材料 V 形切口应力强度因子计算及其在重力坝中的应用

本文用复势理论导出双材料Ｖ形切口的特征方程及切口顶端附近的应力和位移场，首次利用数值分析方法计算出了混凝土坝坝踵区的应力强度因子．典型算例表明，本文计算结果具有较高的计算精度．     

考虑分级开挖的深基坑支护计算

 提出了考虑深基坑变形的一种新的支护结构计算方法——弯杆计算法，在弯杆法的有限元计算中， 通过变换座标的方式考虑上一级开挖的变形，从而达到考虑分级开挖的工况。实例验算表明，该程序能够计算出支护结构变形的变化趋势，并给出了简要的自编计算程序框图。     

土石坝中测斜管接头处预留沉降量的探讨

预留沉降量的确定是土石坝中安装测斜管常见的问题，国内目前尚无定量的技术标准。文章结合小浪底土石坝中测斜管接头处安装预留沉降量的确认过程，提出了具有一定参考意义的量化指标。