Effect of lattice strain on the oxygen vacancy formation and hydrogen adsorption at CeO2(111) surface

Using first-principles calculation, the effect of lattice strain on the oxygen vacancy formation at CeO₂(111) surface has been investigated. The tensile strain facilitates the oxygen vacancy formation at the surface and the compressive strain hinders the process. This is in part due to the strengthening or weakening of the surface Ce–O bond under the lattice strain. On the other hand, a more open surface with a larger lattice constant can better accommodate the larger Ce³⁺ and thus facilitate the structural relaxation of the reduced surface. The studies on the strain effect on the atomic hydrogen adsorption at the defect-free CeO₂(111) surface show that the adsorption strength monotonously increases with the increase of the lattice strain, further confirming the tunable surface chemical activity by lattice strain.     

Ultrastructure of the female reproductive apparatus of the egg parasitoid Gryon pennsylvanicum (Ashmead) (Hymenoptera,Platygastridae)

The growing interest in Leptoglossus occidentalis, the conifer seed bug pest accidentally introduced into Europe in the 1990s, led us to investigate the female reproductive structures of the hymenopteran platygastrid Gryon pennsylvanicum, which is its candidate antagonist for biological control programmes. Our study revealed a genital apparatus with some characteristic features, such as an unusual length of the oviduct (divided into a long proximal and a short distal tract), the absence of accessory glands and the presence of a spermatheca provided with a small spermathecal gland. The ultrastructural investigation revealed that the shorter part of the common oviduct is involved in ion uptake whereas the longer part has two cell types with secretory function: the former with dense bodies and the latter with granular particles. The secretory contents of both are released into the oviduct lumen. The granular particles are formed in a complex of modified endoplasmic reticulum and appear as virus-like particles.     

碳纳米管/聚对甲基吡啶修饰电极测定硝基苯甲酸

采用滴涂法和循环伏安法在玻碳电极上电沉积一层稳定的单壁碳纳米管/聚对甲基吡啶纳米薄膜(SWNTs/POMP)。研究了邻、对硝基苯甲酸在此修饰电极上的电化学行为,建立了电化学同时测定邻、对硝基苯甲酸的新方法。实验结果表明:在0.1 mol/L HClO4溶液中,邻、对硝基苯甲酸在SWNTs/POMP电极上发生不可逆的还原反应,由于碳纳米管和聚合物薄膜的协同效应,SWNTs/POMP电极对邻、对硝基苯甲酸有很好的的电催化作用,并对其响应进行了定量分析。     

稳健偏最小二乘类模型及其在清真香肠红外质量控制中的应用

针对在实际多元质量控制中经常遇到的奇异样品问题,本研究提出了一种稳健偏最小二乘类模型.本方法基于Stahel-Donoho奇异度和样品重加权策略,用稳健的类中心和模型误差构造稳健的决策区间.将本方法用于清真香肠的红外分析,建立了稳健的质量控制方法.在香肠样品的不同部位进行取样,充分研磨后制备溴化钾压片,以空气为背景,测量4000～400 cm-1范围的红外透射光谱.基于73个清真香肠样品和78个非清真样品的光谱数据,研究了新提出的稳健类模型的统计效率和稳健性.在有奇异样品存在的情况下,本方法能有效检出奇异样品,为新样品的预测提供稳健的决策区间.排除奇异样品后,基于原始光谱的模型灵敏性为0.846,特异性为0.936;基于标准正态变量法的模型灵敏性为0.923,特异性为0.974.     

Consensus of second-order and high-order discrete-time multi-agent systems with random networks

This paper studies the convergence and convergence speed for the second-order and the high-order discrete-time multi-agent systems with random networks and arbitrary weights. Random networks mean that the existence of any edge is probabilistic and independent of any other edge. By introducing the agreement set, velocity control gain and high-order state control gain, some consensus protocols are provided for the discrete-time random networks. Moreover, the per-step and asymptotic convergence factors are proposed to measure the convergence and convergence speed. Some examples and simulation results are given to illustrate the effectiveness of the obtained theoretical results.     

Algebraic renormalization of twisted N=2 supersymmetry with Z=2 central extension

We study the renormalizability of (massive) topological QCD based on the algebraic BRST technique by adopting a noncovariant Landau type gauge and making use of the full topological superalgebra. The most general local counter terms are determined and it is shown that in the presence of central charges the BRST cohomology remains trivial. By imposing an additional set of stability constraints it is proven that the matter action of topological QCD is perturbatively finite.     

迁移管的电场强度对真空紫外电离-离子迁移谱仪性能的影响

离子迁移管是离子迁移谱仪的核心部分,它用来产生均匀的电场,以使不同迁移率的离子进行分离。本研究以丙酮为例,详细研究了本课题组所研制的真空紫外电离源-离子迁移谱仪中迁移管的电场参数对离子的灵敏度和分辨率的影响,发现电压的增大灵敏度增大,但是分辨率存在一个最佳的电压,这些结果可用于迁移谱的优化设计。     

A Simple Route to Produce Highly Efficient Porous Carbons Recycled from Tea Waste for High-Performance Symmetric Supercapacitor Electrodes

High-performance porous carbons derived from tea waste were prepared by hydrothermal treatment, combined together with KOH activation. The heat-treatment-processed materials possess an abundant hierarchical structure, with a large specific surface of 2235 m² g⁻¹ and wetting-complemental hydrophilicity for electrolytes. In a two-electrode system, the porous carbon electrodes’ built-in supercapacitor exhibited a high specific capacitance of 256 F g⁻¹ at 0.05 A g⁻¹, an excellent capacitance retention of 95.4% after 10,000 cycles, and a low leakage current of 0.014 mA. In our work, the collective results present that the precursor crafted from the tea waste can be a promising strategy to prepare valuable electrodes for high-performance supercapacitors, which offers a practical strategy to recycle biowastes into manufactured materials in energy storage applications.     

大型偏心结构吊装欠约束问题研究

吊装施工过程中被吊模块的水平度是作业要求的重要指标,通常需要增加配重调平。传统有限元方法需要补充约束以消除单元刚体位移,且需要重复计算平衡方程来求解调平载荷,效率不高。将模块的运动分解为随动坐标系的整体运动以及相对该坐标系的弹性变形,可将欠约束问题化为多体系统的静平衡问题。基于虚功率原理推导了吊装平顺时刻的节点力平衡方程以及相应的切线刚度矩阵,并将配重表示为基础配重与载荷系数相乘的形式。通过对节点力平衡方程求导,得到一组以载荷系数为自变量的微分方程,通过求解微分方程并结合水平度判据,可快速搜寻满足水平度要求的载荷系数。数值算例表明,该方法在解决偏心模块吊装欠约束问题方面具有明显的优势,在确定配重载荷方面具有较快的速度和合理的精度。