A comprehensive review of wheat phytochemicals: From farm to fork and beyond

The health benefits of whole wheat consumption can be partially attributed to wheat's phytochemicals, including phenolic acids, flavonoids, alkylresorcinols, carotenoids, phytosterols, tocopherols, and tocotrienols. It is of increasing interest to produce whole wheat products that are rich in bioactive phytochemicals. This review provides the fundamentals of the chemistry, extraction, and occurrence of wheat phytochemicals and includes critical discussion of several long-lasting issues: (1) the commonly used nomenclature on distribution of wheat phenolic acids, namely, soluble-free, soluble-conjugated, and insoluble-bound phenolic acids; (2) different extraction protocols for wheat phytochemicals; and (3) the chemistry and application of in vitro antioxidant assays. This review further discusses recent advances on the effects of genotypes, environments, field management, and processing techniques including ultrafine grinding, germination, fermentation, enzymatic treatments, thermal treatments, and food processing. These results need to be interpreted with care due to varied sample preparation protocols and limitations of in vitro assays. The bioaccessibility, bioavailability, metabolism, and potential health benefits of wheat phytochemicals are also reviewed. This comprehensive and critical review will benefit scientific researchers in the field of bioactive compounds of cereal grains and also those in the cereal food industry to produce high-quality functional foods.     

Preparation and properties of Eu and Dy co-doped strontium aluminate long afterglow nanomaterials

The long afterglow nanomaterials of strontium aluminate co-doped by Eu and Dy have been synthesized by co-precipitation combined hydrothermal method. The effects of hydrothermal time, calcination time, pH value, the amount of aluminum nitrate, activator, co-activator and flux H₃BO₃ on the fluorescence properties of the product were investigated by means of single factor optimization experiment. Then the orthogonal experiment was employed to obtain the optimal synthesis conditions that are as follows: n_Dy/n_Eu = 2.5, t_c = 2.5?h, n_Eu/n_Sr = 0.02, t_h = 8?h. Subsequently, the optimal synthesis conditions were verified by three repeated experiments, and the obtained products were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and fluorescence spectrometer. The results showed that the synthesized target products all were the mixed crystal phase of SrAl₂O₄ and Sr₄Al_l4O₂₅. The particles presented regular spherical-like with size ~ 100?nm. The dopants Eu and Dy were confirmed existed in the SrAl₂O₄ powders. The fluorescence and afterglow data of the target products were better than that in the orthogonal experiment scheme. The primary emission spectra band was in the range of 400–600?nm with characteristic peak located at ~ 460?nm corresponding to the transitions of Eu²⁺ ions from 4f⁶5d→4f⁷, and the blue light can be observed by naked eyes. The similar fast-decaying and slow-decaying processes were displayed in all the afterglow curves, and the initial afterglow brightness of the target product is apparently higher than that of products synthesized by the orthogonal experiment. The synthesized target products, which show excellent long afterglow performance, present a great application prospects in the aspects of ceramics, plastics, arts and crafts, ink and coating.     

采煤工作面煤层注水工艺优化与应用

针对目前煤层注水存在的施工钻孔效率低、钻孔深度达不到要求、注水钻孔封孔不严、封孔器回收困难等问题，研究注水工艺的改进优化，对钻机、钻具及封孔器进行重新设计选型，形成了一整套的注水装备。该装备的应用提高了施工效率，为降低工作面粉尘危害、抑制工作面瓦斯涌出、防治煤炭自然发火等危害探索出了更加高效的途径和方法。现场应用表明，煤层注水有效地改善了工作面作业环境，为工作面实现高产高效奠定了基础。     

边界润滑条件下表面微细织构减摩特性的研究

表面织构(Surface texture)已被证明是一种提高表面承载力和改善表面摩擦学特性的有效方法。然而在边界润滑条件下,织构对表面摩擦性能的影响机制仍未明确。利用纳米压痕仪在碳钢表面制作了具有不同密度和深度(125~500nm)的划痕的点阵,并通过改进的四球试验机对其在边界润滑下的摩擦性能进行了评价。试验载荷为100~300N,相对滑动速度为0.19~1.33m/s。研究发现:在边界润滑条件下,深度为125nm的低密度"划痕"点阵具有良好的减摩效果。     

Iterative hybrid precoder and combiner design for mmWave MIMO-OFDM systems

Wireless Networks - This paper investigates the problem of hybrid precoder and combiner design for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems...     

金属/介质膜脉宽压缩光栅研究进展

超短超高能量脉冲激光作为研究光和物质相互作用的有力手段得到了广泛研究。啁啾脉冲放大系统是产生这种激光的关键部分,其中脉宽压缩光栅作为啁啾脉冲放大系统的核心组成器件,具有至关重要的作用。金属/介质膜光栅具有高衍射效率、宽工作带宽、高激光损伤阈值等优良特性,受到了广泛关注。详细综述了金属/介质膜脉宽压缩光栅的发展概况,重点分析了金属/介质膜光栅的设计原理和制作工艺,展望了金属/介质膜光栅的发展前景,旨在增进对金属/介质膜脉宽压缩光栅的了解。     

室温辐射探测器用碲锌镉晶体的退火改性研究进展

碲锌镉(CdZnTe)作为一种重要的Ⅱ-Ⅵ族化合物半导体,因其具备优异的光电性能,成为制备室温辐射探测器的理想材料。但生长态的CdZnTe晶体中不可避免地会引入Cd空位、沉淀/夹杂相、杂质和位错等缺陷,严重影响了所制备器件的质量和光电性能。因此,需对生长态晶体进行退火改性处理以提高晶体的质量。本文分析了CdZnTe材料中存在的主要缺陷,重点综述了退火改性工艺如退火温度、退火时间、退火气氛以及退火方式对CdZnTe晶体质量及探测器性能的影响。     

Polarimetric imaging method for target enhancement in haze based on polarimetric retrieval

Polarimetric imaging has been proven to be an effective way in detecting the targets of interest in complicated surroundings by analyzing the polarization property, instead of the intensity, of the light emanating from the objects. Unfortunately, polarimetric imaging encounters difficulty when the surroundings are very scattered, where on the one hand the polarization property of the object light usually becomes very faint after a strong depolarized scattering process; on the other hand, the object light will be blended with the atmospheric light scattered by haze particles (airlight). In this paper, we propose a polarimetric imaging retrieval method that can be used for such challenging conditions. Firstly, the airlight radiance is estimated precisely. Then, the airlight is removed from the hazy images. Finally, the residual polarization property of the object light is regained, which ensures the validity of the polarimetric imaging method in these conditions. The experiments confirm that the proposed method is useful in enhancing polarimetric imaging detection in haze.     

Balancing Intermolecular Interactions between Acceptors and Donor/Acceptor for Efficient Organic Photovoltaics

Promoted by uninterrupted materials and device innovation, organic solar cells have achieved impressive development. However, the complicated intermolecular interactions inside active layers are less understood. Herein, the intermolecular interactions are studied from the dual perspectives of acceptor/acceptor (A/A) and donor/acceptor (D/A), and how these interactions synergistically control the final efficiencies. Three small molecular acceptors (SMAs) are designed with different end-caps, which manipulate the crystallinity and electrostatic potential (ESP) distributions of acceptors, and accordingly, the A/A and D/A intermolecular interactions. The results show that SMA LA17 with low A/A interactions exhibits inferior performance around 12%, owing to its strong D/A interaction with donor PM6, which shapes too miscible morphology and increases charge recombination. Instead, LA16 with strong A/A interactions and moderate D/A interactions delivers improved bulk-heterojunction (BHJ) networks, and therefore, enhances charge transport and diminishes geminate or trap-assisted charge recombination. Consequently, PM6:LA16 records the competitive efficiency of up to 13.74% among the three systems. Therefore, this study deepens the synergistic or balancing effect of the D/A and A/A interactions on BHJ blends for efficient organic solar cells.