摘要：To understand the dispersion behavior of metal oxides on composite oxide supports and with the expectation of developing more feasible catalysts for soot oxidation,CuO/La_(2)Sn_(2)O_(7)samples containing varied CuO loadings were fabricated and characterized by different techniques and density functional theory *** these catalysts,a spontaneous dispersion of CuO on the La_(2)Sn_(2)O_(7)pyrochlore support formed,having a monolayer dispersion capacity of 1.90 mmol CuO/100 m^(2) La_(2)Sn_(2)O_(7)*** loaded below this capacity,CuO exists in a sub-monolayer or monolayer state.X-ray photoelectron spectroscopy(XPS),Raman spectroscopy,and Bader charge and density of states analyses indicate that there are strong interactions between the sub-monolayer/monolayer CuO and the La_(2)Sn_(2)O_(7)support,mainly through the donation of electrons from Cu to Sn at the B-sites of the *** contrast,Cu has negligible interactions with La at the *** suggests that,in composite oxide supports containing multiple metals,the supported metal oxide interacts preferentially with one kind of metal cation in the *** Raman,in situ diffuse reflectance infrared Fourier transform spectroscopy,and XPS results confirmed the formation of both O2^(-)and O2^(2-)as the active sites on the surfaces of the CuO/La_(2)Sn_(2)O_(7)catalysts,and the concentration of these active species determines the soot combustion *** number of active oxygen anions increased with increase in CuO loading until the monolayer dispersion capacity was *** the monolayer dispersion capacity,microsized CuO crystallites formed,and these had a negative effect on the generation of active surface oxygen *** summary,a highly active catalyst can be prepared by covering the surface of the La_(2)Sn_(2)O_(7)support with a CuO monolayer.

摘要：A series of three‐dimensionally ordered macroporous(3DOM)SnO2‐based catalysts modified by the cations Ce4+,Mn3+,and Cu2+have been prepared by using a colloidal crystal templating method and tested for soot combustion under loose contact *** and STEM mapping results confirm that all the secondary metal cations have entered the lattice matrix of tetragonal rutile SnO2 to form non‐continuous solid solutions,thus impeding crystallization and improving the surface areas and pore volumes of the modified *** comparison with regular SnO2 nanoparticles,the 3DOM SnO2 displays evidently improved activity,testifying that the formation of the 3DOM structure can anchor the soot particulates in the macro‐pores,which ensures that the contact of the soot particles with the active sites on the 3DOM skeleton is more easily formed,thus benefiting the target *** the incorporation of the secondary metal cations,the activity of the catalyst can be further improved due to the formation of more abundant mobile oxygen *** summary,these effects are believed to be the major factors responsible for the activity of the catalyst.

摘要：With the objective to investigate the structure-reactivity relationship of CuO/SnO2 and eventually design more applicable catalysts for soot combustion,catalysts with different CuO loadings have been prepared by impregnation *** using X-ray diffraction and X-ray photoelectron spectroscopy extrapolation methods,it is disclosed that CuO disperses finely on the SnO2 support to form a monolayer with a capacity of 2.09 mmol 100 m^-2,which equals 4.8 wt%CuO *** the CuO loading is below the capacity,it is in a sub-monolayer ***,when the loading is above the capacity,CuO micro-crystallites will be formed that coexist with the CuO *** soot combustion activity of the catalyst increases with the CuO loading until it reaches the monolayer dispersion capacity.A further increase in the CuO loading has no evident influence on the *** results have testified that with the addition of CuO onto the SnO2 support,a surface-active oxygen species can be formed,the amount of which also increases significantly with the increase in the CuO loading until it reaches the monolayer dispersion *** the CuO loading further has no evident impact on the amount of surface ***,an apparent monolayer dispersion threshold effect is observed for soot combustion over CuO/SnO2 *** is concluded that the amount of surface-active oxygen sites is the major factor determining the activity of the catalyst.

摘要：精密极薄带因具备高精度、耐腐蚀、优异表面光洁度等性能,被广泛应用于微制造、微电子等高技术领域。二十辊轧机辊系的耦合振动对极薄带的生产有着重要的影响。考虑到轧制工艺和润滑状态等变化形成非线性轧制界面,建立了一种二十辊轧机辊系耦合动力学模型。应用多尺度法求解主共振和内共振的幅频特性方程,分析了不同参数对幅频特性曲线的影响。基于奇异性理论探究了不同参数与系统分岔的关系。同时,根据李雅普诺夫一次近似稳定性判据,结合系统动相平面相轨迹图,对系统稳定性进行判断分析。然后,基于Washout filter控制器原理设计了一种状态反馈控制器,通过对系统进行状态空间表达式变换,分析了控制增益对幅频特性的影响。利用时域图、相位图、频谱图以及Poincaré截面图进行仿真对比,验证了所设计控制器的可行性和有效性,为二十辊轧机振动及其控制的研究提供了一定的理论指导。

摘要：裂缝检测对保证隧道结构安全至关重要,及时发现隧道裂缝缺陷,有利于降低工程维修成本和保障行车安全。然而,传统卷积神经网络在隧道裂缝检测任务中主要侧重提高检测精度和算法复杂度,如何平衡裂缝检测的精度和实时性是当前研究的一个难点。针对这一问题,本文提出一种基于轻量级Transformer的裂缝分割方法 CrackViT。首先,采用卷积神经网络与Transformer混合的MobileViT网络构建裂缝特征提取网络,减少网络模型参数和计算量,并且有效提取裂缝图像全局信息和局部特征信息。然后,提出改进空洞空间金字塔池化解码器实现不同尺度的特征提取和信息融合,实现像素级概率分布。同时,裂缝图像存在细节信息缺失问题,引入高效通道注意力模块,增强对裂缝特征信息的提取能力。此外,针对裂缝与背景类别不平衡问题,设计了在线困难样本挖掘损失函数进行缓解。实验结果表明:在单个3050Ti GPU上,CrackViT算法最终在裂缝数据集上以63 FPS的速度获得了75.62%的IoU,模型参数量仅为2.43 M。CrackViT-L模型精度IoU为76.83%,模型参数量为3.56 M,模型推理速度达到61FPS。算法测试精度优于大多数主流模型,并且需要更少的模型参数。研究结果表明,CrackViT所预测的隧道裂缝分割图像边缘更加清晰和完整,保持推理速度的同时,能够有效检测裂缝,该算法有助于隧道裂缝检测实际应用。

摘要：结构化学是化学专业本科生的主干核心课程,对培养高水平人才具有重要作用。立足于学生兴趣和课程特点,本文提出在结构化学教学中增设量子化学计算实验课。紧扣教学大纲重难点,设计制作了4个基础实验,阐述了内容及实施细节。该改革让学生以计算机为仪器、应用结构化学知识来解决和理解化学问题,提升了学习兴趣和教学效果。

摘要：针对丘陵山地作物移栽的现有半自动和间歇井窖式成穴装备作业效率和质量较低、人工劳动强度较大等问题,为保证井窖穴体的大深度以及穴体轮廓直径一致的农艺要求,基于非圆齿轮平行四杆机构设计一种井窖式成穴机构,在阐述机构的组成结构和工作原理的基础上建立其运动学模型。依据运动学模型运用Matlab开发成穴机构的人机交互可视化辅助界面,利用该界面结合二次正交旋转中心组合试验方法建立成穴机构响应指标与试验因素的回归方程,并通过响应曲面得到其影响趋势和交互关系;以回归方程为基础,采用多目标函数优化获取成穴机构的优化参数组合。根据优化后的机构参数组合研制成穴机构样机及田间作业平台并进行田间试验,试验结果表明:穴体深度为181.7 mm、穴体直立角度为90.5°、穴体直径最大值为75.6 mm、穴体直径最小值为68.5 mm、穴体直径方差为7.5 mm^(2)、穴距为503.1 mm,优化后的成穴机构满足丘陵山地作物移栽井窖成穴的农艺要求。

摘要：本文提出在商务领域的言语交际是一种双维度的活动:一方面与商务活动相关,另一方面又同语言活动相关,因此,该领域的语言研究应该将商务活动与语言活动结合起来进行。本文提出作为商务语言的广告语篇就是这样的言语活动,它的建构存在语言和商务目的双方面的原则限制:1)在语言方面表现出很大程度的"事件依赖性;"2)在商业目的方面,表现出商务活动"移情"的三个方面。

摘要：本研究参照《化学药物制剂研究基本技术指导原则》,筛选A品牌运动营养食品配方,采用单因素法筛选配方以及对综合感官评价进行评分设计正交试验,优化最佳制备工艺,确定其最佳制备工艺并进行功效评价。试验得出,A品牌运动营养粉剂的配方组成合理,制备工艺切实可行,质量检查符合相应粉剂项下检查要求,可满足工业化生产的要求并经抗疲劳功效试验验证有一定程度的抗疲劳作用。

摘要：盆地热体制及深部温度估算对油气和区域地热能资源评估具有重要意义。南方上扬子区是海相油气勘探的重要区块,近年来更是我国页岩气勘探的主要选区。然而,由于数据不足及研究目标的分散,该区的盆地热体制特征还有待深化。结合前人已有地热数据,并整合新近开展的稳态测温数据,我们揭示了上扬子区现今地温梯度、大地热流分布特征,继而估算了1000~6000m埋深处的深部地层温度和2套主要古生界海相烃源岩底界面处的温度。结果表明,上扬子区具有中-低温的地热状态,其现今地温梯度和大地热流的范围(平均值)分别为10~74℃/km(24℃/km)和27~118mW/m^2(64mW/m^2),整体上从东北向西南方向递增,呈现出"东北低、西南高"的分布趋势。1000~6000m埋深处估算温度的分布格局与地温梯度及热流的分布趋势基本一致。东北部的鄂西-湘北地区为低温区,中部的四川盆地其大部分为中温区,西南的云南地区为高温区。上扬子区现今地热分布格局受区域差异构造和岩浆作用控制。结合储层温度估算并综合其他油气地质资料,提出川东的石柱-涪陵、川南的威远-自贡-泸州和宜宾-长宁等区的下志留统龙马溪组页岩层系是上扬子区油气勘探有利区带。