超长寿命小型自然循环铅铋快堆堆芯概念设计研究

以提高铅铋快堆的经济性与固有安全性为目标，开展100 MWt超长寿命小型自然循环铅铋快堆SPALLER-100概念设计，在选用PuN-ThN燃料和²⁰⁸Pb-Bi冷却剂的基础上，提出了一种添加固体慢化剂BeO的燃料组件设计方案，开展了堆芯布置研究和控制棒系统设计，分析了堆芯物理特性与稳态自然循环特性。结果表明：在低燃料装载量和小堆芯体积条件下，SPALLER-100堆芯换料周期达32 a，平均卸料燃耗高达210.38 MW·d/kg(HM)，整个寿期内的反应性系数均为负值。稳态运行工况下燃料包壳、芯块最大温度均小于安全限值，反应堆具备一回路自然循环能力和一定流量自动分配能力。     

Analyzing dissipation effects on the non-classicality witnessing by a qubit via the entangled state representation

ABSTRACT

In this paper, we study detection of the state non-classicality for a quantum harmonic oscillator by a qubit in the presence of dissipation effects. We show that dissipation can enhance the effectiveness of the method in case of using the corrected form of the related nonclassicality witness. Such an improvement is attributed to the fact that dissipation leads to probing a surface, instead of a curve, of the complex plane for non-classicality condition on normally-ordered characteristic function.     

环氧树脂涂层表面亲水性对微藻黏附性能的影响

在固体材料表面黏附成膜是微藻细胞的一种生理特性。近些年基于微藻生物膜的生物过程，如生物膜贴壁培养和防附着技术受到了很多关注。微藻在固体材料表面的黏附受藻细胞与材料表面之间的相互作用的影响，建立黏附强度与材料表面性质参数间的关系对于通过材料选择来强化或控制微藻生物膜具有非常重要的意义。本工作的目的是揭示和明确材料亲疏水性对微藻黏附的影响，提出了一种双酚A环氧(EP)树脂表面亲疏水改性的方法。通过将亲水性的二乙醇胺(DEA)或疏水性的聚甲基聚硅氧烷(PMHS)加入到EP树脂中反应，EP树脂表面水接触角在36.80?~98.34?范围内可通过加入不同量的DEA或PMHS实现任意可调，材料的表面水接触角与DEA或PMHS加入量之间有线性关系。重要的是这种改性方法获得的材料，其形貌、结构、表面粗糙度等表面性质几乎没有变化，从而在研究和关联微藻黏附量与材料表面亲疏水性(表面水接触角)之间的关系时可以排除亲疏水性之外的其他表面性质的影响；其次，考察了小球藻和栅藻在不同亲疏水性材料表面的黏附行为，结果表明小球藻和栅藻在亲水性和疏水性材料表面均能黏附成膜，但在亲水性材料表面黏附更多更快；建立了微藻最大黏附容量与材料表面接触角之间关联关系，表明微藻最大黏附容量随材料表面水接触角的增大而线性降低，栅藻的表面黏附容量比小球藻大。     

基于气动性能与刚度特性的风力机翼型优化设计

结合翼型泛函集成理论与叶片截面刚度矩阵数学计算模型,提出了风力机中等厚度翼型气动性能与结构刚度特性的一体化设计方法,实现了翼型气动性能与叶片截面刚度特性的同时提高。对考虑叶片截面铺层参数变化设计的WQ-B300翼型与DU97-W-300翼型进行了气动性能与结构刚度特性对比分析,结果表明:相比于DU97-W-300翼型,WQ-B300翼型的气动性能与叶片截面刚度性能均有显著提高,其挥舞刚度和摆振刚度分别提高了6.2%和8.4%,验证了该设计方法的可行性,给风力机中等厚度及大厚度翼型设计提供了一种思路。     

Evaluating autostereoscopic 3D baseball games using signal detection theory and receiver operating characteristic space

This study investigates the effects of display technique (2D, autostereoscopic 3D), ball speed (138, 140 km/h), and operation time (5, 10, 15 min) on the four outcomes of signal detection theory (SDT) (i.e., hit, miss, false alarm, correct rejection), β, d’, receiver operating characteristic (ROC) space, Simulator Sickness Questionnaire (SSQ), and the iGroup Presence Questionnaire (IPQ). The results indicated that the display technique was significant on the hit rate, SSQ, and IPQ, where a higher hit rate, visual fatigue, and IPQ were found in the 3D technique. The results also showed that the ball speed was significant on the miss rate and d’, where a low miss rate and high d’ were found in the higher speed of 138 km/h. The results further demonstrated that the operation time was significant on the false alarm rate, correct rejection rate, d’, SSQ, and IPQ, with a long operation time being associated with a better performance for every variable, except the SSQ.Relevance to industryFrom the results obtained regarding the ROC space, this study found that the possibility of participants’ misjudgements was low, and the accuracy of this research is considered reliable. The results of this study could serve as a reference for N3DS and game manufacturers in designing future products.     

Experimental study of the combustion characteristics of methanol‐gasoline blends pool fires in a full‐scale tunnel

The combustion characteristics of methanol‐gasoline blends pool fires were studied in a series of full‐scale tunnel experiments conducted with different methanol and gasoline blends. The parameters were measured including the mass loss rate, the pool surface temperature, the fire plume centerline temperature, the ceiling temperature, the smoke layer temperature profile, the flame height, and the smoke layer interface height. The gasoline components were analyzed by GC‐MS. The effects of azeotropism on the combustion characteristics of the different blends were discussed. On the basis of the results of the fire plume centerline temperature, the ceiling temperature, and the flame height, it shows that the tunnel fire regime gradually switches from fuel controlled to ventilation controlled with increasing gasoline fractions in the blends. The fire plume can be divided into 3 regions by the fire plume centerline temperature for the different blends. The N‐percentage rule to determine the smoke layer interface height is found to be applicable for tunnel fires with different blends for N = 26.     

The thermodynamic characteristics of a Stirling/pulse tube hybrid cryocooler

A Stirling/pulse tube hybrid cryocooler (SPC), comprised of a Stirling cryocooler as the first stage and a pulse tube cryocooler as the second stage, features the ability of shifting cooling capacity between stages by adjusting the movement of the displacer in the first stage. Such an ability allows an SPC to accommodate itself to time-varying heat loads at different temperatures, which makes it a competitive candidate in space applications. However, due to the gas coupling, there exists a significant mutual effect between stages which endows an SPC with special thermodynamic characteristics and has a significant effect on the SPC’s capability of shifting cooling capacity between stages. With the phasor analysis and the thermodynamic analysis, this paper establishes an idealized model of an SPC. The model is then used to study the effect of the second stage on the first stage and reveal the condition that an SPC is able to shift cooling capacity between stages. Also, the model is compared with a Sage numerical model and the two models are consistent on the overall trend. Though it is unable to reflect reality precisely, the idealized model can interpret the mechanism and highlight some of the essential nature of an SPC, which will eventually benefit the appropriate design of an SPC.     

Research on the hot surface ignition of hydrogen‐air mixture under different influencing factors

To further reveal the pre‐ignition characteristics of hydrogen internal combustion engine, the effect of hot surface characteristic parameters on the ignition characteristics of hydrogen‐air mixture was investigated in this research. Based on the prototype of the constant volume combustion bomb with an overhead glow plug, the duration from the heating of the hot surface to the combustion of hydrogen‐air mixture, the so‐called heating duration, was firstly researched under different fuel‐air equivalence ratio, initial temperature, initial pressure, hot surface temperature, and hot surface area, and the influence of each factor on the heating duration was analyzed. The results show that the order of the effect of each factor on the hot surface ignition is as follows: hot surface temperature > initial pressure of hydrogen‐air mixture > equivalent ratio > initial temperature of hydrogen‐air mixture > hot surface area. The influence of the hot surface characteristic parameters on the heating duration was further analyzed in detail. On this basis, the relationship among the critical ignition temperature, the heating duration and the hot surface area was researched and established. The results show that the heating duration is the only major factor affecting the critical ignition temperature. Finally, the research results were applied to analysis the pre‐ignition in hydrogen internal combustion engine.     

考虑速度滑移的多孔质静压气体轴承静特性

对于多孔质材料内的气体流动,基于Darcy定律建立其理论模型,并建立气膜间隙流场的雷诺方程,考虑速度滑移修正方程;将上述2个区域的压力分布方程进行耦合,通过有限元方法对耦合后的压力分布方程进行离散化,用超松弛迭代求解出气膜内各节点的压力分布,分析速度滑移对多孔质静压气体轴承静特性的影响。结果表明,考虑速度滑移所计算的气膜压力分布变化平稳过渡,没有较大的突变。计算轴承的承载力及刚度,结果显示在气密间隙小于15μm时,随着气膜厚度的增大偏心导致的压差增大使承载力不断增大;且当速度滑移系数小于0.1时,速度滑移对轴承承载力及刚度有较大的影响。     

屏边苗式建筑风格及建设初探

考察屏边建筑特色风貌,总结了屏边在打造特色风貌县城建设方面的成功经验,对县城风貌建设提出合理化建议。