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A Computational Study on Lateral Flight Stability of the Cranefly in Hover

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Computer Modeling in Engineering & Sciences 2021年第8期128卷 669-685页

作者： Na Xu Shuaizhi Zhou Chunchen Zhang xiaolei mou School of Electromechanical and Automotive Engineering Yantai UniversityYantai264005China School of Civil Engineering Yantai UniversityYantai264005China

The dynamic flight stability of hovering insects includes the longitudinal and lateral *** results have shown that for the majority of hovering insects the same longitudinal natural modes are identified and the hovering flight in longitudinal is ***,in lateral,the modal structure for hovering insects could be different and the stability property of lateral disturbance motion is not as robust as that of longitudinal *** cranefly possesses larger aspect ratio and lower Reynolds number,and such differences in morphology and kinematics may make the lateral dynamic stability *** this paper,the lateral flight stability of the cranefly in hover is investigated by numerical ***,the stability derivatives are acquired by solving the incompressible Navier–Stokes ***,the dynamic stability characteristics are checked by analyzing the eigenvalues and eigenvectors of the linearized *** results indicate that the lateral dynamic modal structure of cranefly is different from most other insects,consisting of three natural modes,and the weakly oscillatory mode illustrates the hovering lateral flight is nearly *** neutral stability is mainly caused by the negative derivative of roll-moment ***-velocity,which can be attributed to the weaker‘changingLEV-axial-velocity’*** results suggest that insects in nature may exhibit different dynamic stabilities with different morphological and kinematic parameters,which should be considered in the designs of flapping wing air vehicles.

关键词： Flapping flight cranefly lateral flight stability natural modes of motion computational fluid dynamics

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翅尖轨迹对食蚜蝇悬停时气动特性的影响

北京航空航天大学学报 2016年第12期42卷 2603-2609页

作者：牟晓蕾许娜烟台大学土木工程学院烟台264005 烟台大学机电汽车工程学院烟台264005

食蚜蝇悬停飞行时的抬升角相对较小,在上下拍起始和结束时刻要比拍动中部的大,这样就使得翅尖的拍动轨迹呈现出浅"U"形。为了分析该翅尖轨迹是否会对其气动特性产生影响,利用计算流体力学的方法分别计算了4只食蚜蝇在考虑抬升角和忽略... 详细信息

食蚜蝇悬停飞行时的抬升角相对较小,在上下拍起始和结束时刻要比拍动中部的大,这样就使得翅尖的拍动轨迹呈现出浅"U"形。为了分析该翅尖轨迹是否会对其气动特性产生影响,利用计算流体力学的方法分别计算了4只食蚜蝇在考虑抬升角和忽略抬升角2种情形下的气动力,分析对比了2种情形下的不同时刻绕翅膀的瞬时流线,并计算比较了2种情形下气动功率系数与平均举力系数的比值。研究结果表明:抬升角的存在会使其维持体重所需的举力增加10%左右;举力增大的同时能耗却比忽略抬升角情形下要低3%左右。

关键词：翅尖轨迹食蚜蝇悬停飞行气动力功率

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侧风对拍动翅气动力的影响

北京航空航天大学学报 2017年第11期43卷 2310-2315页

作者：牟晓蕾许娜烟台大学土木工程学院烟台264005 烟台大学机电汽车工程学院烟台264005

昆虫在自然界中飞行时多会受到侧风的干扰,因此了解侧风作用下昆虫拍动翅上气动力的变化对昆虫飞行机理的研究工作具有重要意义。应用计算流体力学(CFD)方法模拟了存在侧风时拍动翅上绕流,并与正常悬停情况进行对比,从侧风的方向和强度... 详细信息

昆虫在自然界中飞行时多会受到侧风的干扰,因此了解侧风作用下昆虫拍动翅上气动力的变化对昆虫飞行机理的研究工作具有重要意义。应用计算流体力学(CFD)方法模拟了存在侧风时拍动翅上绕流,并与正常悬停情况进行对比,从侧风的方向和强度2个方面考察了其对拍动翅气动特性的影响。结果表明:侧风对拍动翅气动特性的改变包含2个流动机制的贡献,即相对速度效应和前缘涡轴向速度效应,且从翅尖吹向翅根的侧风与从翅根吹向翅尖的侧风对气动力的影响有着显著的不同;而不同强度的同向侧风下,气动力的改变类似,仅存在数值上的差异。

关键词：侧风昆虫气动力悬停数值模拟

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抬升角对食蚜蝇飞行动稳定性的影响

北京航空航天大学学报 2021年第7期47卷 1372-1378页

作者：许娜周帅至牟晓蕾烟台大学机电汽车工程学院烟台264005 烟台大学土木工程学院烟台264005

抬升角的存在对昆虫飞行时的气动力会产生不同程度的影响,其对昆虫飞行动稳定性的影响也非常值得探索。首先,求解Navier-Stokes方程得到了有抬升角时食蚜蝇的纵向与横向稳定性导数;然后,用特征模态分析法研究其动稳定性。结果表明:有抬... 详细信息

抬升角的存在对昆虫飞行时的气动力会产生不同程度的影响,其对昆虫飞行动稳定性的影响也非常值得探索。首先,求解Navier-Stokes方程得到了有抬升角时食蚜蝇的纵向与横向稳定性导数;然后,用特征模态分析法研究其动稳定性。结果表明:有抬升角时,在侧向来流作用下食蚜蝇的滚转力矩对应的导数比无抬升角时明显减小,而其余导数无明显变化,导数减小是由于抬升角的存在使得有侧向来流时因左右翅举力不同产生的正向滚转力矩数值明显减小,而由侧向力产生的负向滚转力矩数值略有增大,从而使得其总的负向滚转力矩数值增大;但有侧向来流时滚转力矩所对应导数的减小并未引起食蚜蝇飞行动稳定性的改变,其纵向和横向的特征模态仍与无抬升角时相同。

关键词：抬升角食蚜蝇飞行动稳定性 Navier-Stokes方程运动模态

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褶皱位置对蜻蜓滑翔翼气动性能的影响

航空动力学报 2021年第7期36卷 1434-1442页

作者：许娜周帅至牟晓蕾烟台大学机电汽车工程学院山东烟台264005 烟台大学土木工程学院山东烟台264005

改变昆虫翅膀的褶皱结构可以优化翼型的气动性能,有利于微型飞行器的气动设计。以蜻蜓翼作为参考,采用计算流体力学(CFD)的方法计算了攻角范围为0°~20°,雷诺数范围为700~2300时褶皱位于前缘、尾缘和中部位置时三种翼型的滑翔气动性能... 详细信息

改变昆虫翅膀的褶皱结构可以优化翼型的气动性能,有利于微型飞行器的气动设计。以蜻蜓翼作为参考,采用计算流体力学(CFD)的方法计算了攻角范围为0°~20°,雷诺数范围为700~2300时褶皱位于前缘、尾缘和中部位置时三种翼型的滑翔气动性能。结果表明:在不同攻角和雷诺数下,褶皱位于尾缘的翼型具有最大的升力系数和升阻比,滑翔气动性能最优;当雷诺数为1500,攻角为10°时,褶皱位于尾缘的翼型时均升力系数分别比位于前缘和中部的翼型提高了58%和82%,升阻比分别提高了49%和33%;这是由于尾缘褶皱中的涡起到了延缓前缘涡脱落的作用,使前缘涡更为集中,更贴近壁面。

关键词：微型飞行器褶皱滑翔计算流体力学气动性能

The Minimal Affine Total Variation in Minkowski Spaces

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数学进展 2025年第1期54卷 164-176页

作者： mou Shuang School of Mathematics and Statistics Shaanxi Normal UniversityXi’anShaanxi710119P.R.China

In this paper,we use the solution of the even functional Minkowski problem to show that there is a minimizing affine Minkowski total variation of the function of bounded ***,for the Minkowski total variation,we use th... 详细信息

关键词： convex body minimal surface area Minkowski space bounded variation

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机制砂中不同因素对混凝土性能影响研究

国防交通工程与技术 2020年第4期18卷 47-49,70页

作者：牟晓磊中铁十八局集团第一工程有限公司河北涿州072750

为了揭示机制砂不同因素对混凝土性能的影响规律并提高机制砂在混凝土施工过程中的利用水平,立足于三因素三水平正交试验,同时结合宏观性能测试和耐久性研究,分析混凝土配合比设计时机制砂石粉含量、泥含量以及砂率对混凝土性能的影响... 详细信息

为了揭示机制砂不同因素对混凝土性能的影响规律并提高机制砂在混凝土施工过程中的利用水平,立足于三因素三水平正交试验,同时结合宏观性能测试和耐久性研究,分析混凝土配合比设计时机制砂石粉含量、泥含量以及砂率对混凝土性能的影响。结果表明:①混凝土中石粉含量对混凝土的强度影响最大,其次是砂率,再次是泥含量;②制备高强度混凝土的条件是石粉含量为12%、砂率为42%、泥含量为2.5%。冻融性研究表明:适量的石粉、泥含量、砂率可以优化硬化混凝土的孔结构和空隙率,有利于混凝土强度及抗冻性能的提高。

关键词：机制砂正交试验石粉含量泥含量砂率

Induced neural stem cells regulate microglial activation through Akt-mediated upregulation of CXCR4 and Crry in a mouse model of closed head injury

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Neural Regeneration Research 2025年第5期20卷 1416-1430页

作者： mou Gao Qin Dong Dan Zou Zhijun Yang Lili Guo Ruxiang Xu Department of Neurosurgery Sichuan Academy of Medical Sciences and Sichuan Provincial People’s HospitalSchool of MedicineUniversity of Electronic Science and Technology of ChinaChengduSichuan ProvinceChina Department of Neurosurgery Chinese PLA General HospitalBeijingChina Department of Neurology Fu Xing HospitalCapital Medical UniversityBeijingChina

Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and *** previously reported that induced neural stem cells can modulate the behavior of activated microglia via CXCL12/CXCR4 signaling,influencing their activation such that they can promote neurological ***,the mechanism of CXCR4 upregulation in induced neural stem cells remains *** this study,we found that nuclear factor-κB activation induced by closed head injury mouse serum in microglia promoted CXCL12 and tumor necrosis factor-αexpression but suppressed insulin-like growth factor-1 ***,recombinant complement receptor 2-conjugated Crry(CR2-Crry)reduced the effects of closed head injury mouse serum-induced nuclear factor-κB activation in microglia and the levels of activated microglia,CXCL12,and tumor necrosis factor-α.Additionally,we observed that,in response to stimulation(including stimulation by CXCL12 secreted by activated microglia),CXCR4 and Crry levels can be upregulated in induced neural stem cells via the interplay among CXCL12/CXCR4,Crry,and Akt signaling to modulate microglial *** agreement with these in vitro experimental results,we found that Akt activation enhanced the immunoregulatory effects of induced neural stem cell grafts on microglial activation,leading to the promotion of neurological recovery via insulin-like growth factor-1 secretion and the neuroprotective effects of induced neural stem cell grafts through CXCR4 and Crry upregulation in the injured cortices of closed head injury ***,these beneficial effects of Akt activation in induced neural stem cells were positively correlated with the therapeutic effects of induced neural stem cells on neuronal injury,cerebral edema,and neurological disorders post–closed head *** conclusion,our findings reveal that Akt activation may enhance the immunoregulatory effects of induced neura

关键词： Akt signaling cerebral edema closed head injury Crry CXCR4 induced neural stem cell microglia neuroinflammation

Concentration and retention of ascorbic acid,carotenoids,and sugars in fresh-cut lettuce in modified atmosphere packaging

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Horticultural Plant Journal 2025年第1期11卷 303-313页

作者： Jinita Sthapit Kandel Ivan Simko Ryan J.Hayes Beiquan mou U.S.Department of Agriculture Agricultural Research ServiceSam Farr United States Crop Improvement and Protection Research Center1636 E.Alisal StreetSalinasCA93905USA U.S.Department of Agriculture Agricultural Research ServiceForage Seed and Cereal Research Unit3450 SW Campus WayCorvallisOR97331USA U.S.Department of Agriculture Agricultural Research ServiceSunflower and Plant Biology Research1616 Albrecht Blvd NFargoND58102USA

Fresh-cut lettuce is widely used in ready-to-eat salads sold in modified atmosphere packages (MAP).Even in MAP,fresh-cut lettuce has short shelf life that results in loss of *** cultivars exhibit genetic variation for shelf life in MAP,but their variation for nutrient retention is not *** accessions were evaluated for initial content of ascorbic acid (AsA),carotenoids,and sugars and their retention in *** with high content and/or good retention of one or more nutrients were *** romaine accession ‘Floricos’ had high levels of all the three *** with relatively high retention of all the three nutrients were ‘Salinas 88’,‘Siskiyou’,‘Solar’,SM09A,‘Romance’,and ‘Green Towers’.Romaine cultivars,‘Balady Barrage’,‘Green Towers’,and ‘Darkland’ had relatively high initial levels of all tested nutrients and good rate of their *** was no clear correlation between initial AsA/carotene concentrations and their retention rates,suggesting that besides content,retention of nutrients should also be a breeding target in a lettuce nutritional improvement *** analyses with the Pearson's correlation coefficient determined a negative relationship between tissue deterioration(AUDePS) and retention of all tested nutrients[r of-0.52 (P<0.0001) for AsA,-0.27 (P<0.01) for total carotene,and-0.59 (P<0.0001) for total sugars],suggesting that an increase in tissue deterioration intensifies nutrient ***-sense heritability (H^(2)) across the experiments was0.15 for AsA,0.23 for total carotene,and 0.50 for total *** of germplasm with high nutrient content,extended shelf life and good nutrient retention provides valuable information for the lettuce industry and associated breeding programs.

关键词： Lettuce Shelf life Nutrient retention Ascorbic acid Carotene Sugars