Activation cross-section measurement of a sort of nuclide produced with a target including two isotopes

Based on a formula used to calculate the activation cross-section sum of two reactions producing a sort of nuclide with a target including two isotopes, the related problems in some references have been analyzed and discussed. It is pointed out that the calculation methods of the cross-section sum of two reactions producing the same radioactive nuclide for two isotopes in some references are improper and usually it is impossible to obtain the correct cross-section sum of two reactions producing the same radioactive nuclide for two isotopes in the case of using natural samples. At the same time, the related concepts are clarified and the correct processing method and representation are given. The comparison with the experimental results show that the theoretical analysis results are right.     

空间调制傅里叶变换红外光谱仪干涉系统透射效率研究

光学系统表面的反射与材料的吸收会降低空间调制傅里叶变换红外光谱仪中光的透过率。通过对干涉系统透过率函数的计算和对采样干涉图与复原光谱的仿真,结果显示透过率函数作用下的干涉图像对比度下降,复原光谱中的谱线强度发生衰减。分析表明,干涉图像对比度的下降主要是由分束器对入射光的有效反射引起的,而谱线强度的衰减则是由与增透膜的光强反射率R₁、分束膜的光强反射率R₂和材料的吸收系数α有关的透射效率函数所决定。通过分析论证,对于本文所研究的光谱波段,可以不考虑材料的吸收,所以透射效率主要由R₁和R₂决定。由此,将透射效率作为设计指标,根据系统的设计需求,就可以得到增透膜与分束膜光强反射率的容限值。     

子孔径拼接中系统误差的修正方法

为了提高大口径光学元件子孔径拼接测量的检测精度,提出一种平面绝对测量技术,修正子孔径拼接过程中产生的系统误差。利用改进的三面互检法获得参考平面的面形数据,采用这些测量数据构建基于Zernike多项式的参考面面形误差修正波面,在拼接过程中运用误差修正波面对获得的子孔径测量数据进行实时修正,并与全口径直接测量结果进行对比,结果PV（peak value,PV,峰谷值）误差从0.072 1 减少到0.028 6 。结果表明该方法有效减少了参考平面系统误差对拼接测量精度的影响,提高了大口径光学元件的检测精度。     

NUMERICAL ANALYSIS OF THE STRESS CONCENTRATION IN REVERSE K-JOINTS

逆K 型管节点广泛应用于海洋平台,其强度是平台结构安全评估的重要课题. 基于ANSYS 软件,应用分区域网格划分法,建立含焊缝的逆K 型管节点有限元模型,分别计算了在轴向载荷、平面内弯矩和平面外弯矩作用下焊缝周围热点应力的分布情况. 通过对105 组逆K 型管节点模型进行分析,获得了其在3 种基本载荷作用下沿焊缝的应力集中系数（stress concentration fctor,SCF）,并对主管和支管的SCF 分别进行研究,得出了几何参数对主管和支管的SCF 及极值位置的影响规律.     

Effects of Bond Alternation on the Ground-State Phase Diagram of One-Dimensional XXZ Model

The ground-state properties and quantum phase transitions (QPTs) of the one-dimensional bond-alternative XXZ model are investigated by the infinite time-evolving block decimation (iTEBD) method. The bond-alternative effects on its ground-state phase diagram are discussed in detail. Once the bond alternation is taken into account, the antiferromagnetic phase (Δ > 1) will be destroyed at a given critical point and change into a disordered phase without nonlocal string order. The QPT is shown to be second-order, and the whole phase diagram is provided. For the ferromagnetic phase region (Δ < -1), the critical point r^c always equals 1 (independent of Δ), and the QPT for this case is shown to be first-order. The dimerized Heisenberg model is also discussed, and two disordered phases can be distinguished by with or without nonlocal string orders. Both the bipartite entanglement and the fidelity per site, as two kinds of model-independent measures, are capable of describing all the QPTs in such a quantum model.     

应用理性优化蚁群算法提高激光三维复制的重现度

三维复制人工耳和打印手枪把激光三维复制技术推向新的一页。激光三维扫描是激光应用中一个新兴的重要领域,在三维复制中扮演着无可替代的角色,其复制精度在目前所有复制技术中是最高的。而重现度标志着复制结果与复制对象几何形状上的一致程度,是激光三维复制最重要的指标。分析了激光三维复制的误差,得出激光扫描的点云数据处理是减小误差、提高重现度的关键所在的结论。主要创新点在于,在传统蚁群算法的基础上,将提出理性优化蚁群算法应用于激光三维复制中的数据处理。经计算对比发现,有效减小了复制的误差,提高了复制的重现度。     

基于云模型的自适应量子免疫克隆算法

利用云模型能够兼顾随机性和模糊性的品质,提出一种基于云模型的自适应量子免疫克隆算法.使用云算子代替通用的量子旋转门这一量子进化算法核心算子用于寻优变异操作;通过控制云算子间的协作,实现算法在进化过程中对搜索范围的动态调整,使算法具有较强的全局搜索能力;同时,补充针对性的优化方案,有效避免了算法陷入局部最优.对标准数值优化问题的仿真对比实验表明,该算法具有寻优能力强、搜索精度高、稳定度好等优点;对非线性系统的参数估计仿真实验,该算法也取得了对参数的高精度有效估计.     

砂岩岩石力学参数各向异性研究

对胜利油田不同深度的四口井的砂岩岩芯进行了三轴压缩试验和动态岩石力学参数试验。根据获得的垂直地层方向和平行地层方向的试验数据,计算了各岩石力学参数的各向异性系数。通过分析围压以及深度对各向异性系数的影响,给出了砂岩峰值强度各项异性系数、静泊松比各向异性系数、纵波波速各向异性系数、纵横波速比和动泊松比各向异性系数与深度的拟合公式。发现峰值强度、纵波波速和纵横波速比的各向异性系数都随着深度的增加而减小,而泊松比各向异性系数随着深度的增加而增大。动、静弹性模量各向异性系数与深度相关性都很差,动弹性模量各向异性较弱,静弹性模量相对较强。     

毫秒激光烧蚀镍靶高效率制备NiO纳米立方体

利用长脉宽毫秒激光烧蚀浸没在循环水中的金属镍靶制备了大量的氧化镍(NiO)纳米立方体, 通过透射电子显微镜(TEM)、 选区电子衍射(SAED)、 X射线衍射(XRD)和能量色散谱(EDS)等手段表征了产物的形貌和结构. 结果表明, 高功率密度激光产生的高温高压条件是形成NiO纳米立方体的最重要因素. 激光功率密度高于10⁴ W/cm²时可以生成NiO纳米立方体, 当功率高于该阈值时激光首先将镍靶烧蚀为金属液滴, 高温的金属液体加热周围液体, 并由于液体的限制效应使得压力进一步升高, 最后金属液滴与液体发生表面反应生成NiO纳米立方体.     

Synthesis and Photovoltaic Properties of Non-fullerene Solution Processable Small Molecule Acceptors

Two non-fullerene small molecules, BT-C6 and BT-C12, based on the vinylene-linked benzothiadiazole- thiophene(BT) moiety flanked with 2-(3,5,5-trimethylcyclohex-2-en-1-ylidene)malononitrile have been synthesized and characterized by solution/thin film UV-Vis absorption, photoluminescence(PL), and cyclic voltammetry(CV) measurements. The two molecules show intense absorption bands in a wide range from 300 nm to 700 nm and low optical bandgaps for BT-C6(1.60 eV) and for BT-C12(1.67 eV). The lowest unoccupied molecular orbital(LUMO) levels of both the molecules are relatively higher than that of [6,6]-phenyl C61 butyric acid methyl ester(PCBM), promising high open circuit voltage(V_oc) for photovoltaic application. Bulk heterojunction(BHJ) solar cells with poly(3-hexylthiophene) (P3HT) as the electron donor and the two molecules as the acceptors were fabricated. Under 100 mW/cm² AM 1.5 G illumination, the devices based on P3HT:BT-C6(1:1, mass ratio) show a power conversion efficiency(PCE) of 0.67%, a short-circuit current(J_sc) of 1.63 mA/cm², an open circuit voltage(V_oc) of 0.74 V, and a fill factor(FF) of 0.56.