基于图像法的粮食物料悬浮速度研究

图像法是一种基于图像处理技术的非接触式测试手段.随着计算机技术与图像处理技术的发展,图像法被广泛应用于各个领域的测试工作中.通过对图像法测试技术的研究和对粮食物料在垂直管道中流动状态的观察、分析,提出一种利用图像法测量粮食物料悬浮速度的新方法.用该方法测定了几种常见粮食颗粒的悬浮速度,并分析了各种因素对颗粒悬浮速度的影响,可为粮食气力输送机械的设计、优化提供参考依据.     

集成改进AHP与XGBoost算法的食品安全风险预测模型:以大米为例

近年来,我国在食品质量安全管控方面已有较大提升,但伴随着食品产业规模的增大,检验需求量的增多,食品安全检测数据出现高维、复杂且非线性等特征,这些特征会导致定量分析数据利用率低,从而直接影响以数据为载体的风险预测模型的准确性.为提高风险预测模型的准确性,以食品安全检测数据为基础,提出了一种集成层次分析法与极端梯度提升树算...     

基于OD矩阵的电动出租车充电负荷时空特性预测分析

电动出租车规模化发展带来的充电负荷是城市电网中的新型负荷。电动出租车充电负荷与其商业运营特点紧密相关。融合出租交通的OD矩阵信息和出租商业运营时间窗,分析乘客出行需求特征以及出租车行驶状态转换特征,采用蒙特卡洛法,建立出租交通充电需求模拟仿真流程。计及出租车载客和寻客状态行驶速度,以及出行路线和快、慢充电能补给方式决策上的差异性,量化仿真出租车运营随机性、分散性对充电需求时空分布的影响。以某城市电动出租车未来规模化推广为算例,预测电动出租充电需求时空分布,为该地区电动出租车充电网络及配电网规划提供支撑。     

基于可信区块链和可信标识的粮油质量安全溯源研究

粮油质量安全关乎国家的稳定发展,但目前还存在诸多粮油质量安全问题,特别是异构系统间数据的可信互联、高效互通得不到保障。因此,本研究首先在对粮油质量安全全链条信息流转特性进行分析的基础上,构建粮油质量安全全链条架构,并对典型环节进行关键信息分类。然后基于可信区块链和可信标识构建粮油质量安全可信溯源模型,对区块数据结构、标识体系编码规则、存储方式等进行定义和重构,并提出链网连接器的概念及具体架构方案。最后,以典型粮油品种小麦为例,基于超级账本Fabric开源框架设计并研发了小麦质量安全可信溯源系统,对模型进行了系统实现验证和案例分析。结果表明,研究的模型及系统实现了粮油质量安全全链条信息互联互通,并且保证了跨链信息交互的安全与全流程可追溯性。     

基于蒙特卡罗仿真的湖库水质预测及富营养化风险评估方法

已有的水质预测研究通常是单值预测,并以此为依据分析富营养化状态,具有一定的偶然性和不确定性。结合水质动力学模型,提出了一种基于蒙特卡罗仿真的湖库水质预测及富营养化风险评估方法。在已知水质动力学模型水质指标和模型参数的先验分布基础上,利用蒙特卡罗仿真预测水质指标的演化过程,获得未来时刻水质指标取值的概率分布,实现水质预测。进一步,构造综合营养状态指数,结合水质指标预测结果,计算综合营养状态指数的概率分布和处于不同营养程度的概率,实现富营养化风险评估。仿真结果表明,该方法能够有效实现水质预测和富营养化分析,且考虑更加全面、准确,克服了单值预测结果带来的偶然性。     

Rational Design of Multifunctional Fe@γ‐Fe2O3@H‐TiO2 Nanocomposites with Enhanced Magnetic and Photoconversion Effects for Wide Applications: From Photocatalysis to Imaging‐Guided Photothermal Cancer Therapy

Titanium dioxide (TiO₂) has been widely investigated and used in many areas due to its high refractive index and ultraviolet light absorption, but the lack of absorption in the visible–near infrared (Vis–NIR) region limits its application. Herein, multifunctional Fe@γ‐Fe₂O₃@H‐TiO₂ nanocomposites (NCs) with multilayer‐structure are synthesized by one‐step hydrogen reduction, which show remarkably improved magnetic and photoconversion effects as a promising generalists for photocatalysis, bioimaging, and photothermal therapy (PTT). Hydrogenation is used to turn white TiO₂ in to hydrogenated TiO₂ (H‐TiO₂), thus improving the absorption in the Vis–NIR region. Based on the excellent solar‐driven photocatalytic activities of the H‐TiO₂ shell, the Fe@γ‐Fe₂O₃ magnetic core is introduced to make it convenient for separating and recovering the catalytic agents. More importantly, Fe@γ‐Fe₂O₃@H‐TiO₂ NCs show enhanced photothermal conversion efficiency due to more circuit loops for electron transitions between H‐TiO₂ and γ‐Fe₂O₃, and the electronic structures of Fe@γ‐Fe₂O₃@H‐TiO₂ NCs are calculated using the Vienna ab initio simulation package based on the density functional theory to account for the results. The reported core–shell NCs can serve as an NIR‐responsive photothermal agent for magnetic‐targeted photothermal therapy and as a multimodal imaging probe for cancer including infrared photothermal imaging, magnetic resonance imaging, and photoacoustic imaging.     

基于经验模态分解和BP神经网络的油气两相流流型辨识

基于经验模态分解（empidcal mode decomposition，EMD）BP神经网络，提出了油气两相流流型辨识的新方法。应用EMD将差压信号分解成不同频率尺度上的单组分之和，并提取组分的归一化能量作为流型辨识特征量。BP神经网络以这些能量特征量为输入对油气两相流不同流型（包括泡状流、塞状流、层状流、弹状流和环状流）进行分类。实验结果表明，本文提出的流型辨识方法是有效的，其中泡状流、塞状流、层状流、弹状流和环状流的辨识精度分别为100％、89．4％,93．3％、96.3％和96.9％。     

Enhancing the Stability of Perovskite Quantum Dots by Encapsulation in Crosslinked Polystyrene Beads via a Swelling–Shrinking Strategy toward Superior Water Resistance

Organic/inorganic hybrid lead halide perovskites are promising optoelectronic materials due to their unique structure, excellent properties, and fascinating potential applications in lighting, photovoltaic, etc. However, perovskite materials are very sensitive to moisture and polar solvent, which greatly hinders their practical applications. Here, highly luminescent perovskite–polystyrene composite beads with uniform morphology are prepared via a simple swelling–shrinking strategy. This process is carried out only in nonpolar toluene and hexane without the addition of any polar reagents. As a result, the as‐prepared composite beads not only retain high luminescence but also exhibit superior water‐resistant property. The composites emit strong luminescence after being immersed into water over nine months. Moreover, even in some harsh environments such as acid/alkali aqueous solution, phosphate buffer solution, and Dulbecco's modified eagle medium biological buffers, they still preserve high luminescence. The applications in light‐emitting diodes and cellular labeling agents are also carried out to demonstrate their ultrastability.     

城市与建筑的象征意义仿生研究

象征意义仿生作为边缘的叛逆设计思潮,对现代建筑的发展起着重要的推动作用.运用比较方法,考察了东西方在城市规划和建筑领域中运用象征意义仿生的历史,阐述了象征意义仿生这种认识方法在城市规划与建筑中发展演变的过程,试图解读城市和建筑仿生所表达的象征意义,从而提炼出其对当前城市和建筑设计的借鉴意义.     

泥岩底辟成因及对油气成藏的影响——以尼日尔Termit盆地底辟区为例

底辟多为受断层影响的次生底辟,而尼日尔Termit盆地早期断层不发育,同生底辟现象明显。通过实验模拟证实研究区泥岩底辟形成机理为：区域应力场压性分量为主动力,挤压塑性层上拱,再辅以不均匀负荷两侧挤压造成。根据受力类型及所处构造位置,将研究区底辟分为坡折—挤压型、低凸—引张差异负荷型和凹陷—差异负荷型。泥岩底辟对油气成藏的影响主要为：①欠压实高压泥岩具有生烃潜力,在达到生烃门限后,可以生烃;②底辟上拱改善了油气垂向运移能力,产生的微裂缝利于高压流体排出;③泥岩底辟形成的圈闭主要为辟顶背斜和辟边岩性遮挡圈闭;④坡折带的中斜坡临近生烃凹陷,砂体条件优越,该部位底辟形成的圈闭为油气的有利聚集区。勘探实例表明：在底辟活动程度最强的东部坡折带,靠近Moul凹陷一侧的下组合探井,试油均获成功。