双偏振极化干涉技术实时研究三磷酸腺苷与其适配体相互作用

利用双偏振极化干涉(Dual polarization interferometry,DPI)测量技术实时研究了三磷酸腺苷(ATP)与其适配体(ATP-binding aptamer, ABA)间的相互作用.将单链ABA固定在DPI氮化硅芯片上,采用DPI技术实时监测ATP与固定的ABA的相互作用过程中敏感层的质量、厚度、密度的变化.通过详细分析敏感层质量变化,得到ATP与ABA间的结合速率常数 (ka=4.66 × 10.3 L/(mol·s)、解离速率常数(kd =1.70 × 10.-2·s.-1)、结合常数 (KA=2.7 × 10.5 L/mol)和解离常数(KD =3.7 × 10.-6 mol/L).通过测定敏感层质量、厚度和密度随ATP浓度的变化,分别建立了测定ATP的方法,检出限(LOD, 3σ)分别为0.22 μmol/L(质量变化)、0.14 μmol/L(厚度变化)、0.32 μmol/L(密度变化).本研究利用DPI技术揭示了ABA与ATP相互作用中结构变化的实时信息,构建了新型ATP传感器,用于实际血清样品中ATP的检测,结果令人满意.     

Analysis on high-temperature oxidation and growth stress of iron-based alloy using phase field method

High-temperature oxidation is an important property to evaluate thermal protection materials. However, since oxidation is a complex process involving microstructure evolution, its quantitative analysis has always been a challenge. In this work, a phase field method (PFM) based on the thermodynamics theory is developed to simulate the oxidation behavior and oxidation induced growth stress. It involves microstructure evolution and solves the problem of quantitatively computational analysis for the oxidation behavior and growth stress. Employing this method, the diffusion process, oxidation performance, and stress evolution are predicted for Fe-Cr-Al-Y alloys. The numerical results agree well with the experimental data. The linear relationship between the maximum growth stress and the environment oxygen concentration is found. PFM provides a powerful tool to investigate high-temperature oxidation in complex environments.     

多光谱测量材料冲击辐射特性的温度反演算法

材料的冲击辐射温度是高温-高压作用下状态方程研究的重要物理参量,对武器研制、科学研究和工业制造意义重大。针对冲击辐射温度具有瞬时非接触、测量环境噪声复杂、温度反演发射率不可测等特点,设计了一种新的温度反演方法,以提高温度获取精度。根据约束优化理论,将乘子罚函数法与粒子群算法相结合,实现两种模型的串联,并改进粒子群-乘子罚函数算法。结果表明该混合模型求解方法充分结合了两种单一算法的优势,提高了冲击辐射测试数据的温度反演精度与运算效率,为研究材料冲击辐射的真实温度提供了保障。     

界面增强多晶点阵结构的耐撞吸能性能

3D打印技术有力促进了金属点阵材料的发展,而碰撞吸能是点阵材料的重要应用领域之一,为此综述了课题组近期在界面增强点阵吸能方面的研究。受金属材料微观变形机理中晶界强化机制的启发,通过在点阵结构中引入晶界和孪晶界等宏观界面构型,构造了含多个界面的多晶点阵结构,研究其耐撞吸能性能。具体而言,构造了胞元构型为简单立方、面心立方和三斜晶系的不同多晶点阵结构试件,通过一系列参数化有限元模拟,并结合增材制造技术开展验证性实验,研究了晶粒尺寸(晶界密度)、界面两侧晶向差、界面取向角度等参数对结构压溃变形模式和吸能性能的影响,发现对称性强的界面(如孪晶界)可以增强点阵结构的吸能性能。进一步研究发现,描述材料微观强化机理的Hall-Petch关系仍然适用于所提宏观多晶点阵结构。该研究可为发展新型轻质点阵吸能结构提供一定的参考。     

Orientation and ellipticity dependence of high-order harmonic generation in nanowires

It has been predicted that high-order harmonic generation (HHG) in nanowires has the potential to scale up photon energy and harmonic yield. However, studies on HHG in nanowires are still theoretical and no relevant experimental results have been reported as yet. Our experimental observation of the high-order harmonic in cadmium sulfide nanowires (CdS NWs) excited by a mid-infrared laser is, to our knowledge, the first of such study, and it verifies some of the theoretical results. Our experimental results show that the observed harmonics are strongest when a pump laser is parallel to the nanowires. Therefore, the theoretical prediction that harmonics are strongest under the nanowires parallel to the laser field is confirmed experimentally, and this can be used to determine the orientation of the nanowire. In addition, harmonics are sensitive to the variation of pump light ellipticities. This orientation dependence opens new opportunities to access the ultrafast and strong-field physics of nanowires.     

具不同官能团钌(Ⅱ)邻菲啰啉配合物氧淬灭性能的比较研究

设计并制备具不同官能团的钌(Ⅱ)邻菲啰啉配合物——[Ru(bpy)2(phen-NO2)](PF6)2(1),[Ru(bpy)2(phen-Br)](PF6)2(2),[Ru(bpy)2(phen-NH2)](PF6)2(3),[Ru(bpy)2(bphen)](PF6)2(4),其中,bpy为2,2’-联吡啶,phen-NO2为5-硝基-邻菲啰啉,phen-Br为5-溴-1,10-菲啰啉,phen-NH2为5-氨基-邻菲啰啉,bphen为4,7-二苯基-邻菲啰啉.借助核磁共振(NMR)、红外光谱(FTIR)、元素分析、紫外可见光谱(UV-vis)和荧光光谱法对其进行了分析与表征.结果表明:配合物2～4在蓝-紫色可见光区域有较强吸收、可发射出明亮的橙红色荧光、具荧光量子效率(Φ)高、激发态寿命(τ)长、Stocks位移值较大(147～180 nm)和优良的氧致荧光淬灭性能(Ksv≥3.5,(I0/I)max≥4.0)等光物理性质.其中,具接枝型官能团氨基的配合物3的量子效率(Φ)=10%,τ=381.8 ns,Ksv=3.49,(I0/I)max=4.33;而溴修饰的配合物2以高达18%的荧光量子效率、634.7 ns的激发态寿命、180 nm的Stocks位移和Ksv=4.59,氧淬灭参数(I0/I)max=5.29,使之最有希望成为接枝型、较高性能的光学氧传感器的候选氧敏指示剂.     

互相关及高阶谱核材料富集度识别方法

针对基于传统核材料识别系统中特征值易受系统噪声影响且精确度不够的问题,将高阶统计特征概念引入252Cf源驱动核系统特征提取和识别之中,提出了一种基于互相关函数与高阶统计特征的252Cf源驱动核材料富集度识别方法。通过互相关运算及高阶统计分析,得到核系统信息的三维特征图像,并在此基础上开展了待测核材料(235U)的富集度实验研究与分析识别工作。实验研究结果表明,该识别方法能够较好地降低背景辐射噪声与电子学系统噪声。与传统识别方法相比,对于核部件富集度变化,该算法的敏感性与鲁棒性均有大幅提高。     

H2/n-C4H10/Air预混气在Swiss-Roll燃烧器中的催化燃烧特性

在微尺度催化燃烧中,由于燃料和氧气对于催化剂表面活性位的竞争,导致了可燃下限为富燃的情况。为了提高燃料利用率,拓宽可燃范围,本文在正丁烷/空气的混合气中加入一定量的氢气,在Swiss-roll燃烧器内研究了氢气/正丁烷/空气预混气的燃烧特性。结果表明,氢气能够有效拓宽正丁烷的可燃范围,可燃下限能够低于1,以贫燃的条件实现高燃料利用率。对于稳定燃烧温度的实验结果表明,燃烧器最高温度出现在富燃料一侧。     

Numerical simulation and experimental validation of a direct current air corona discharge under atmospheric pressure

Air corona discharge is one of the critical problems associated with high-voltage equipment. Investigating the corona mechanism plays a key role in enhancing the electrical insulation performance. An improved self-consistent multi-component two-dimensional plasma hybrid model is presented for the simulation of a direct current atmospheric pressure corona discharge in air. The model is based on plasma hydrodynamic and chemical models, and includes 12 species and 26 reactions. In addition, the photoionization effect is introduced into the model. The simulation on a bar-plate electrode configuration with an inter-electrode gap of 5.0 mm is carried out. The discharge voltage-current characteristics and the current density distribution predicted by the hybrid model agree with the experimental measurements. In addition, the dynamics of volume charged species generation, discharge current waveform, current density distribution at an electrode, charge density, electron temperature, and electric field variations are investigated in detail based on the model. The results indicate that the model can contribute valuable insights into the physics of an air plasma discharge.     

利用节点效率评估复杂网络功能鲁棒性

为了克服现有复杂网络鲁棒性研究模型只考虑节点失效的局部影响性和网络拓扑鲁棒性的缺陷, 提出了一种利用节点效率来评估复杂网络功能鲁棒性的方法. 该方法综合考虑节点失效的全局影响性, 利用网络中节点的效率来定义各节点的负载、极限负载和失效模型, 通过打击后网络中最终失效节点的比例来衡量网络的功能鲁棒性, 并给出了其评估优化算法. 实验分析表明该方法对考虑节点负载的复杂网络功能鲁棒性的评定可行有效, 对于大型复杂网络可以获得理想的计算能力.