7 MeV注入剥离膜系统设计

设计了一台注入能量为7 MeV的快循环同步加速器剥离膜装置,介绍了主体结构设计及高精度换膜运动结构,实现膜片精确定位及在线换膜功能。针对注入参数对膜片开展分析计算,分析了7 MeV的负氢离子束注入时相应的碳膜材料的反应截面及不同厚度的剥离效率,给出了膜片厚度的参数选择。对所设计膜片的温升和寿命进行分析,膜片的温升最高点达到755 K,远小于同类的加速器的剥离膜温度,具有更高的寿命和可靠性。     

Multi-way chemometric methodologies and applications: A central summary of our research work

Multi-way data analysis and tensorial calibration are gaining widespread acceptance with the rapid development of modern analytical instruments. In recent years, our group working in State Key Laboratory of Chemo/Biosensing and Chemometrics in Hunan University has carried out exhaustive scientific research work in this area, such as building more canonical symbol systems, seeking the inner mathematical cyclic symmetry property for trilinear or multilinear decomposition, suggesting a series of multi-way calibration algorithms, exploring the rank estimation of three-way trilinear data array and analyzing different application systems. In this present paper, an overview from second-order data to third-order data covering about theories and applications in analytical chemistry has been presented.     

Finite-Time Stochastic Stability Analysis of Permanent Magnet Synchronous Motors with Noise Perturbation

In this paper, we study the finite-time stability of permanent magnet synchronous motors (PMSMs) with noise perturbation. To eliminate the chaos in a PMSM and allow it to reach a steady state more quickly within a finite time, we propose a novel adaptive controller based on finite-time control theory. Finite-time stability implies optimal convergence time and better robustness. Finally, numerical simulations are performed to demonstrate the effectiveness and feasibility of our new results.     

改进最小费用流相位解包裹算法

在不同解包裹算法中,最小费用流(MCF)解包裹法可以限制残差点误差远程扩散,并将误差优先限制在低相干区域,有利于保证高相干区域解包裹结果不受干扰,精度较高,但残差点数量较多时计算效率很低.为缩短解包裹时间,提出一种残差点预处理方法.该方法将残差点视作正负电荷,通过电场力,引导距离较近的异号残差点互相抵消,大幅减少残差点...     

2024铝合金激光多次冲击诱导残余应力状态分布规律

采用高功率激光器多次冲击2024铝合金,用X射线衍射技术分析了冲击区域的残余应力,研究了冲击残余应力状态分布规律,并用其评价激光冲击强化效果。研究表明,随着冲击次数增加,塑变量及塑性应变梯度逐渐减小,测点是双向压应力状态,而4次冲击时,塑性应变梯度增大,光斑中心是单向压应力状态,其他点是双向压应力状态。当激光功率密度为2.8 GW/cm2时,3次冲击强化效果最佳,材料是二向压应力状态,残余最大主应力及应力强度的均值最大,方差最小,分布基本均匀,塑性应变梯度较小。     

高灵敏度表面光学非线性测量法

提出了一种测量非透明材料表面光学非线性的新方法：挡板反射4F测量法。该方法在反射4F相位相干成像系统的基础上,在4F系统的像平面放置一个与系统入射面光阑相匹配的不透明挡板,通过测量不同情况下的反射率,实现对材料光学非线性的测量。详细介绍了该方法的基本原理,并通过数值模拟计算了入射角对测量灵敏度的影响。该方法具有单脉冲测量,可同时得到材料的非线性吸收与折射系数等特点。结果表明,在相同条件下挡板反射4F测量法的灵敏度比反射Z扫描方法高2个数量级。     

异面带状线馈电的宽带双极化蝶形天线

针对通信与雷达系统对双极化与宽带天线的要求,提出了一种基于带状线馈电的双极化蝶形天线。通过两对互相正交的蝶形阵子实现了天线的双极化,并采用一种新型的微带线转异面带状线的巴伦给两对正交蝶形阵子平衡馈电。异面带状线为平衡传输线,满足了蝶形阵子对于平衡馈电的要求。在馈电点处由同轴线对微带线馈电,经渐变微带线转化为异面带状线,最后由两组异面带状线给两对正交蝶形阵子馈电。测得该天线实现了69.23%的阻抗带宽,在6.8～14 GHz频带内电压驻波比(VSWR)小于2。为使天线单向辐射且改善天线增益,将天线放置于反射吸收腔内。测得天线在6.8～18 GHz的频宽内VSWR基本小于3,天线增益在8～12 GHz频带内大于0.11 dB,天线前后瓣比大于15 dB。因此,所提出的双极化蝶形天线可用于宽带通信系统中。     

求解双曲守恒律方程的WENO型熵相容格式

通过在单元交界面处进行高阶WENO重构,得到了一种求解双曲型守恒律方程的WENO型熵相容格式。用该格式对一维Burgers方程和Euler方程进行数值模拟,结果表明,该格式具有高精度、基本无振荡性等特点。

     

双微环谐振腔耦合的双波长半导体激光器（英）

提出一种新颖的单片集成双微环耦合的双波长半导体激光器结构。集成于激光腔内的2个微环谐振腔作为模式选择滤波器,通过游标效应选择谐振模式,同时还可作为等效的反射镜面以形成行波腔。这种无需解理的行波激光腔代替了需要解理面的法布里-珀罗驻波腔。理论仿真表明,跟驻波腔结构相比,行波腔双微环激光器结构简单,可获得约34 mA的较低的阈值电流和大于31 dB的边模抑制比。合理地控制有源区的增益峰值和谐振模式分布,该激光器能提供一致性和稳定性较好的双波长激光输出。     

Highly Dispersed Vanadia Anchored on Protonated g-C3N4 as an Efficient and Selective Catalyst for the Hydroxylation of Benzene into Phenol

The direct hydroxylation of benzene is a green and economical-efficient alternative to the existing cumene process for phenol production. However, the undesired phenol selectivity at high benzene conversion hinders its wide application. Here, we develop a one-pot synthesis of protonated g-C₃N₄ supporting vanadia catalysts (V-pg-C₃N₄) for the efficient and selective hydroxylation of benzene. Characterizations suggest that protonating g-C₃N₄ in diluted HCl can boost the generation of amino groups (NH/NH₂) without changing the bulk structure. The content of surface amino groups, which determines the dispersion of vanadia, can be easily regulated by the amount of HCl added in the preparation. Increasing the content of surface amino groups benefits the dispersion of vanadia, which eventually leads to improved H₂O₂ activation and benzene hydroxylation. The optimal catalyst, V-pg-C₃N₄-0.46, achieves 60% benzene conversion and 99.7% phenol selectivity at 60 ^oC with H₂O₂ as the oxidant.