益生菌发酵胡萝卜汁活性成分与抗氧化活性研究

研究了鼠李糖乳杆菌（Lactobacillus rhamnus）发酵胡萝卜汁前后游离酚、结合酚、有机酸、游离氨基酸及抗氧化活性的变化。结果表明,鼠李糖乳杆菌发酵后胡萝卜汁中的游离态酚类物质含量明显增加（P＜0.05）,而结合态酚类物质的含量明显下降（P＜0.05）,其中槲皮素相较于发酵前提高了243.91%;发酵后乳酸含量最高,比发酵前提高了5.376 mg/mL;发酵后苏氨酸（0.13 mg/g）、丝氨酸（0.25 mg/g）、甘氨酸（0.34 mg/g）、蛋氨酸（0.05 mg/g）和赖氨酸（0.12 mg/g）含量均明显升高（P＜0.05）。抗氧化活性实验结果表示,发酵后的胡萝卜汁对DPPH和羟基自由基的清除率及总还原力分别为70.6%和26.45%及0.58±0.01,比发酵前分别提高了30.42%和21.45%及28.89%。     

糙米重组米的回生特性

采用差示扫描量热仪和质构仪研究了糙米重组米的Avrami方程及硬度,探讨了糙米重组米的回生特性。结果表明：糙米重组米的Avrami参数n值均小于1,以一次成核的方式结晶;糙米重组米淀粉中的直链淀粉含量对Avrami参数n有非常显著的影响,对支链淀粉的最大回生度没有显著的影响;参数n和结晶速率k之间成极显著负相关;最大回生度与结晶速率k成显著负相关;硬度可以有效地反映出糙米重组米的回生程度。     

基于改进配准测度的红外与可见光图像配准

异源图像配准中,由于图像的成像机理差异,图像像素强度关联和旋转畸变是不可避免的两大问题,针对图像像素强度关联问题,提出了基于辐射不变特征变换（radiation-variation insensitive feature transform,RIFT）的图像配准算法,对图像间像素关联差异小的图像对配准有良好的精度,但对旋转畸变图像会产生较多错误匹配。对于旋转畸变问题,传统的ORB（oriented fast and rotated brief）算法,对旋转图像的配准有一定的稳定性,但对于强度变化不明显的图像对,特征点检测质量较低,配准精度不理想。因此本文将相位一致性（phase consistency,PC）融合进ORB算法,利用相位信息代替传统的图像强度信息,再构造旋转不变性BRIEF特征描述子,对图像像素强度变化和旋转畸变均具有鲁棒性。用图像像素强度关联不明显的红外图像和可见光图像进行配准实验,本文算法针对不同旋转幅度的图像的配准精度较高,RMSE稳定在1.7~2.1,优于RIFT算法,在特征点检测数量、配准精度和效率等性能上均有良好性能。     

无机纤维棉生物膜载体反应器脱氮性能及优化

研究了一种生态多孔纤维棉(EPFC)的生物挂膜性能,并将其应用于脱氮反应器中,考察不同DO水平与装置设计(填充率、孔密度)对脱氮效果的影响.结果表明,EPFC是一种良好的生物挂膜材料.DO含量对反应器脱氮效果影响显著,在ρ(DO)=10～11 mg/L、HRT=5 d时NH4+-N去除率最高97.41％;TN去除率在ρ...     

A novel narrow band blue-emitting phosphor Rb2ZrSi3O9: Eu2+ with low thermal quenching and high quantum efficiency

Developing phosphors with narrow band emission and excellent performance is the main goal of current leading research. In this study, a novel narrow band blue-emitting phosphor Rb₂ZrSi₃O₉: Eu²⁺ was prepared that can be fully excited by near ultraviolet (NUV) light, emits a bright blue light peak at 470 nm, and has a full width at half maximum (FWHM) of 60 nm. The synthesized Rb₂ZrSi₃O₉: Eu²⁺ had excellent photoluminescence properties that were reflected in its good thermal stability (up to 82%) and high internal quantum efficiency (up to 75%). These remarkable luminescence properties were mainly ascribed to the highly symmetric and dense crystal structure composed of [Si₃O₉]^6- ring pairs. Multiple emission centers in the Rb₂ZrSi₃O₉: Eu²⁺ phosphor were confirmed through the photoluminescence (PL) spectra and time-resolved (PL) spectra. A bright warm WLED device with a low correlated color temperature (3386 K) and high color-rendering index (CRI~89.3) was produced by combining the blue phosphor with (Sr, Ba)₂SiO₄: Eu²⁺ and CaAlSiN₃: Eu²⁺ and NUV (380 nm). The results indicate that Rb₂ZrSi₃O₉: Eu²⁺ could be a promising phosphor for use in WLEDs.     

Glass-ceramic phosphors for solid state lighting: A review

Solid state lighting, including phosphor converted light-emitting diodes (LEDs) and laser diodes (LDs), have released high demand to develop thermally stable phosphors. For this purpose, inorganic glass-ceramics (GCs) embedded with phosphor particles can act as competitive candidates. They are superior to traditional phosphors or resin/silica composites through successfully overcoming thermal aging and color temperature drifting problems and simultaneously maintaining high luminescent efficiencies. Inorganic GC phosphors can be classified into devitrified glass-ceramics, PiG (Phosphor-in-Glass) and sintered glass-ceramics. This review summarized the recent progress on LED/LD GC phosphors from the aspects of design principles, synthesis methods, microstructure-property relationships and their application studies. In addition, some challenging issues (e.g., crystallization behavior of luminous phase in glass, corrosion behavior of phosphor by glass matrix) are also discussed in detail. Significant issues of glass-ceramics packed LED/LD, such as luminescence efficiency, chromaticity, correlated color temperature and color gamut, are sorted out as well. Potential research directions are further suggested for not only developing new glass-ceramic phosphors but feeding upon various practical application.     

最优单次重合跳频序列集设计

单次重合跳频序列可以最大限度地提高频率的使用率，降低频率相互之间的碰撞，被广泛用于多址通信中。文章基于中国剩余定理，构造了3类关于周期汉明相关理论界最优的单次重合跳频序列集, 并给出了单次重合跳频序列集汉明相关的性质。     

Structural origin of thermally induced refractive index changes in Yb3+/Al3+/P5+/F−-co-doped silica glass

In this work, the relationship among the thermal history, refractive index (RI), and structures of Yb³⁺/Al³⁺/P⁵⁺/F⁻-co-doped silica glass is studied. We reveal the structural origin of the thermally induced RI change in the Heraeus F300 and Yb³⁺/Al³⁺/P⁵⁺/F⁻-co-doped silica glasses with different states of thermal history by advanced solid-state nuclear magnetic resonance and Raman scattering techniques, and the effect of the thermal history on the beam quality of Yb³⁺-doped large-mode-area photonic crystal fiber (LMA PCF). The structural analysis demonstrates that the RI change in the glass is inextricably linked to the change in the AlPO₄ domains, coordination number of the Al and Si–O–Si rings. An intimate and direct connection of the thermally induced physical behaviors is developed with the structural pictures of glasses, and the beam quality of the LMA PCF is greatly improved by proper thermal annealing. The results provide a significant reference for the precise manipulation of the numerical aperture of Yb³⁺-doped active fiber.