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Journal of Thermal Science 2024年第2期33卷 602-610页

作者： wang songbai WU Yadong CHEN Yong CAO Zhipeng School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai200240China AECC Sichuan Gas Turbine Establishment Chengdu610500China

The complex flow phenomenon of rotating instability(RI) and its induced non-synchronous vibration(NSV) have become a significant challenge as they continuously increase aerodynamic load.This study aims to provide an understanding of the non-synchronous blade vibration phenomenon caused by the rotating instability of a transonic axial compressor rotor.In this case,blade vibrations and non-synchronous excitation are captured by strain gauges and unsteady wall pressure transducer sensors.Unsteady numerical simulations for a full-annulus configuration are used to obtain the non-synchronous flow excitation.The results show that the first-stage rotor blade exhibits an NSV close to the first bending mode;NSV is accompanied by a sharp increase in pressure pulsation;amplitude can reach 20%,and unsteady aerodynamic frequency will lock in a structural mode frequency when the blade vibrates in a large-amplitude motion.The predicted NSV frequency aligns well with the experimental results.The dominant mode of circumferential instability flow structure is approximately 47% of the number blades,and the cell size occupies 2-3 pitches in the circumferential direction.The full-annulus unsteady simulations demonstrate that the streamwise oscillation of the shedding and reattachment vortex structure is the main cause of NSV owing to the strong interaction between the tip leakage and separation vortices near the suction surface.

关键词： non-synchronous vibration transonic axial compressor rotor blade rotating instabilities unsteady flow

基于流固耦合的压气机转子叶片非同步振动分析

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力学学报 2024年第3期56卷 635-643页

作者：汪松柏霍嘉欣赵星陈勇吴亚东张军上海交通大学机械与动力工程学院上海200240 中国航发四川燃气涡轮研究院成都610500

压气机转子叶片非同步振动是近年来发现的一类新气动弹性问题,表现为叶片振动频率与转频不同步且具有锁频现象,严重影响航空发动机的可靠性和运行安全,目前对其产生机理并不完全清楚.为了深入研究压气机内不稳定流动与叶片非同步振动之... 详细信息

压气机转子叶片非同步振动是近年来发现的一类新气动弹性问题,表现为叶片振动频率与转频不同步且具有锁频现象,严重影响航空发动机的可靠性和运行安全,目前对其产生机理并不完全清楚.为了深入研究压气机内不稳定流动与叶片非同步振动之间的耦合机制,基于时间推进的方法建立了多级压气机转子叶片全环的双向流固耦合模型,数值研究了刚性叶片与非同步振动柔性叶片的非定常流场、气流激励频率和结构响应特征,揭示了压气机转子叶片非同步振动的流固耦合机制.结果表明:近失速工况下,转子叶尖吸力面径向分离涡的周期性脱落及再附过程是导致叶尖压力剧烈波动的主要原因,其3倍谐波激励频率与转子一阶弯曲固有频率接近,提供了叶片非同步振动的初始气流激励源.叶片非同步振动发生时,位移响应表现为等幅值的极限环特征,振动以一阶弯曲模态主导,径向分离涡产生的非整数倍气流激励频率及其谐波频率最终锁定为叶片一阶弯曲固有频率,非同步振动的运动胁迫使得相邻通道叶尖流场周向趋于一致.研究成果及对叶片非同步振动流固耦合机制的认识可为压气机内部不稳定流动诱发的叶片振动失效分析提供有益参考.

关键词：压气机转子叶片非同步振动流固耦合极限环非定常流动

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航空发动机风扇转子叶片抗鸟撞改进设计

航空动力学报 2024年第2期39卷 86-94页

作者：汪松柏牛潇霍嘉欣张震相江柏均刘昭威中国航发四川燃气涡轮研究院成都610500

为提高航空发动机风扇转子叶片抗鸟撞能力,基于光滑粒子流体动力学(SPH)方法及LSDYNA显式动力学分析软件对风扇转子叶片的抗鸟撞能力进行评估,分析了不同关键设计参数对气动性能和叶片抗鸟撞性能的影响。结果表明:真实鸟体撞击风扇转子... 详细信息

为提高航空发动机风扇转子叶片抗鸟撞能力,基于光滑粒子流体动力学(SPH)方法及LSDYNA显式动力学分析软件对风扇转子叶片的抗鸟撞能力进行评估,分析了不同关键设计参数对气动性能和叶片抗鸟撞性能的影响。结果表明:真实鸟体撞击风扇转子叶片后,主要造成叶片前缘变形、卷边和撕裂。风扇气动性能随叶片前缘半径增大而降低,当前缘半径超过0.25 mm后,风扇的稳定裕度急剧下降;最大厚度位置后移对风扇气动性能有益,但风扇转子叶片抗鸟撞能力下降。在保证风扇气动性能的前提下,通过合理选取设计参数,对风扇转子叶片进行改进设计,改进后叶片的抗鸟撞能力由30 g提高到50 g,抗鸟撞能力得到明显提升。

关键词：风扇转子叶片光滑粒子流体动力学(SPH) 鸟撞改进设计气动性能

金纳米团簇检测食品中NO_(2)^(–)的综合实验设计

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实验技术与管理 2024年第2期41卷 127-134页

作者：王松柏董晓芮李文艳薛柳燕李英奇山西大学化学化工学院化学国家级实验教学示范中心山西太原030006

以金纳米团簇的合成、表征和应用为例,将纳米团簇科学前沿引入化学专业本科生综合实验教学。与国标(GB5009.33—2016)检测NO_(2)^(-)方法相比,该方法不需要对肉制品样品进行脱脂、脱蛋白等处理,检测效率显著提高,此外还对剩菜剩饭和多... 详细信息

以金纳米团簇的合成、表征和应用为例,将纳米团簇科学前沿引入化学专业本科生综合实验教学。与国标(GB5009.33—2016)检测NO_(2)^(-)方法相比,该方法不需要对肉制品样品进行脱脂、脱蛋白等处理,检测效率显著提高,此外还对剩菜剩饭和多次煮沸水中的NO_(2)^(-)含量进行了检测,为健康的饮食习惯提供依据。实验涉及蛋白质变性、氧化还原反应、软硬酸碱规则、荧光传感等相关理论知识,有助于学生了解交叉学科前沿,还可以通过多模块教学,从多维度、多视角培养学生的学习兴趣以及知识迁移和综合应用能力。

关键词：鸡蛋清四氯金酸金纳米团簇 NO_(2)^(–)检测综合实验

GENERALIZED ORLICZ-TYPE SLICE SPACES, EXTRAPOLATION AND APPLICATIONS

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Acta Mathematica Scientia 2022年第5期42卷 2001-2024页

作者：王松柏 School of Mathematics and Statistics Chongqing Three Gorges UniversityChongqing 404100China

We introduce a class of generalized Orlicz-type Auscher-Mourgoglou slice space,which is a special case of the Wiener amalgam.We prove versions of the Rubio de Francia extrapolation theorem in this space.As a consequence,we obtain the boundedness results for several classical operators,such as the Calderón-Zygmund operator,the Marcinkiewicz integrals,the Bochner-Riesz means and the Riesz potential,as well as variational inequalities for differential operators and singular integrals.As an application,we obtain global regularity estimates for solutions of non-divergence elliptic equations on generalized Orlicz-type slice spaces if the coefficient matrix is symmetric,uniformly elliptic and has a small(δ,R)-BMO norm for some positive numbers δ and R.

关键词： generalized Orlicz space extrapolation Hardy-Littlewood maximal operator Muckenhouptweight variation inequality

基于启动子和信号肽优化提高谷氨酰胺酶在枯草芽孢杆菌中的分泌表达

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微生物学通报 2024年第5期51卷 1536-1549页

作者：毛泽敬张祖政陈铭望松柏牛硕余华顺张彦郑贤良安琪酵母股份有限公司湖北宜昌443003 酵母功能湖北省重点实验室湖北宜昌443003 农业微生物挖掘与利用全国重点实验室湖北宜昌443003 三峡大学生物与制药学院湖北宜昌443002

【背景】谷氨酰胺酶(glutaminase)是一种能够催化L-谷氨酰胺水解生成L-谷氨酸和氨的酶,在食品、医药等领域有重要的应用价值。【目的】研究不同启动子和信号肽对谷氨酰胺酶分泌表达的影响、构建能高效分泌表达谷氨酰胺酶的枯草芽孢杆菌(... 详细信息

【背景】谷氨酰胺酶(glutaminase)是一种能够催化L-谷氨酰胺水解生成L-谷氨酸和氨的酶,在食品、医药等领域有重要的应用价值。【目的】研究不同启动子和信号肽对谷氨酰胺酶分泌表达的影响、构建能高效分泌表达谷氨酰胺酶的枯草芽孢杆菌(Bacillus subtilis)工程菌株,提高谷氨酰胺酶的产量。【方法】选用枯草芽孢杆菌SCK6作为表达宿主,构建带有不同启动子和信号肽的谷氨酰胺酶表达载体及重组菌株,分析不同基因元件对谷氨酰胺酶表达及分泌的影响,筛选最优启动子和信号肽,组合优化,构建高效分泌表达谷氨酰胺酶的工程菌株。【结果】实现了谷氨酰胺酶在枯草芽孢杆菌中的分泌表达,在以P_(HpaII)-P_(aprE)为启动子、YndA为信号肽的条件下,摇瓶发酵胞外最高酶活达到6.7U/mL。【结论】通过对启动子、信号肽关键基因元件进行筛选组合,构建了一株高效分泌表达谷氨酰胺酶的菌株,为酶的高效分泌表达提供了一种有效的方法。

关键词：枯草芽孢杆菌谷氨酰胺酶启动子信号肽分泌表达

Fatigue Crack Propagation Law of Corroded Steel Box Girders in Long Span Bridges

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 201-227页

作者： Ying wang Longxiao Chao Jun Chen songbai Jiang Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education School of Civil EngineeringSoutheast UniversityNanjing211189China Jiangsu Provincial Engineering Construction Standard Station Nanjing210036China

In order to investigate the fatigue performance of orthotropic anisotropic steel bridge decks,this study realizes the simulation of the welding process through elastic-plastic finite element theory,thermal-structural sequential coupling,and the birth-death element method.The simulated welding residual stresses are introduced into the multiscale finite element model of the bridge as the initial stress.Furthermore,the study explores the impact of residual stress on crack propagation in the fatigue-vulnerable components of the corroded steel box girder.The results indicate that fatigue cracks at the weld toe of the top deck,the weld root of the top deck,and the opening of the transverse diaphragm will not propagate under the action of a standard vehicle load.However,the inclusion of residual stress leads to the propagation of these cracks.When considering residual stress,the fatigue crack propagation paths at the weld toe of the transverse diaphragm and the U-rib weld toe align with those observed in actual bridges.In the absence of residual stress,the cracks at the toe of the transverse diaphragm with a 15%mass loss rate are categorized as type I cracks.Conversely,when residual stress is considered,these cracks become I-II composite cracks.Residual stress significantly alters the cumulative energy release rate of the three fracturemodes.Therefore,incorporating the influence of residual stress is essential when assessing the fatigue performance of corroded steel box girders in long-span bridges.

关键词： Residual stress crack propagation corroded steel box girder cumulative energy release rate

Threshold of climate extremes that impact vegetation productivity over the Tibetan Plateau

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Science China Earth Sciences 2024年第6期67卷 1967-1977页

作者： Zhenggang PIAO Xiangyi LI Hao XU Kai wang Shuchang TANG Fei KAN songbai HONG College of Urban and Environmental Sciences Peking UniversityBeijing 100871China

Vegetation growth is adversely impacted by multiple climate extremes related to the water and thermal stress over the Tibetan Plateau(TP).However,it remains unknown at which stress level these climate extremes can trigger the abrupt shifts of vegetation response to climate extremes and result in the maximum vegetation response across TP.To fill this knowledge gap,we combined the hydrometeorological data and the satellite-derived vegetation index to detect two critical thresholds that determine the response of vegetation productivity to droughts,high-temperature extremes,and low-temperature extremes,respectively,during 2001-2018.Our results show that the response of vegetation productivity to droughts rapidly increases once crossing -1.41±0.6 standard deviation(σ)below the normal conditions of soil moisture.When crossing-2.98σ±0.9σ,vegetation productivity is maximum damaged by droughts.High-temperature extremes,which have the two thresholds of 1.34σ±0.4σand 2.31σ±0.4σover TP,are suggested to trigger the strong response of vegetation productivity at a milder stress level than low-temperature extremes(two thresholds:-1.44σ±0.5σand-2.53σ±0.8σ).Moreover,we found the compounded effects of soil moisture deficit in reducing the threshold values of both high-and low-temperature extremes.Based on the derived thresholds of climate extremes that impact vegetation productivity,Earth System Models project that southwestern TP and part of the northeastern TP will become the hotspots with a high exposure risk to climate extremes by 2100.This study deciphers the high-impact extreme climates using two important thresholds across TP,which advances the understanding of the vegetation response to different climate extremes and provides a paradigm for assessing the impacts of climate extremes on regional ecosystems.

关键词： Tibetan Plateau Climate extremes Thresholds Vegetation productivity

Weak Hardy-type spaces associated with ball quasi-Banach function spaces I:Decompositions with applications to boundedness of Calderón-Zygmund operators

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Science China Mathematics 2021年第9期64卷 2007-2064页

作者： Yangyang Zhang Dachun Yang Wen Yuan songbai wang Laboratory of Mathematics and Complex Systems(Ministry of Education of China) School of Mathematical SciencesBeijing Normal UniversityBeijing100875China College of Mathematics and Statistics Hubei Normal UniversityHuangshi435002China

Let X be a ball quasi-Banach function space on R^(n).In this article,we introduce the weak Hardytype space WH_(X)(R^(n)),associated with X,via the radial maximal function.Assuming that the powered HardyLittlewood maximal operator satisfies some Fefferman-Stein vector-valued maximal inequality on X as well as it is bounded on both the weak ball quasi-Banach function space WX and the associated space,we then establish several real-variable characterizations of WH_(X)(R^(n)),respectively,in terms of various maximal functions,atoms and molecules.As an application,we obtain the boundedness of Calderón-Zygmund operators from the Hardy space H_(X)(R^(n))to WH_(X)(Rn),which includes the critical case.All these results are of wide applications.Particularly,when X:=M^(q)_(p)(R^(n))(the Morrey space),X:=L^(p)(R^(n))(the mixed-norm Lebesgue space)and X:=(EΦq)t(Rn)(the Orlicz-slice space),which are all ball quasi-Banach function spaces rather than quasiBanach function spaces,all these results are even new.Due to the generality,more applications of these results are predictable.

关键词： ball quasi-Banach function space weak Hardy space Orlicz-slice space maximal function atom molecule Calderón-Zygmund operator

Solderability and intermetallic compounds formation of Sn-9Zn-xAg lead-free solders wetted on Cu substrate

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Rare Metals 2009年第6期28卷 656-660页

作者： CHEN Wenxue XUE songbai wang Hui wang Jianxin HAN Zongjie College of Materials Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

The eutectic Sn-9Zn alloy was doped with Ag （0 wt.%-1 wt.%） to form Sn-9Zn-xAg lead-free solder alloys. The effect of the addition of Ag on the microstructure and solderability of this alloy was investigated and intermetallic compounds （IMCs） formed at the solder/Cu interface were also examined in this study. The results show that, due to the addition of Ag, the microstructure of the solder changes. When the quantity of Ag is lower than 0.3 wt.%, the needle-like Zn-rich phase decreases gradually. However, when the quantity of Ag is 0.5 wt.%-1 wt.%, Ag-Zn intermetallic compounds appear in the solder. In particular, adding 0.3 wt.% Ag improves the wetting behavior due to the better oxidation resistance of the Sn-9Zn solder. The addition of an excessive amount of Ag will deteriorate the wetting property because the gluti- nosity and fluidity of Sn-9Zn-（0.5, 1）Ag solder decrease. The results also indicate that the addition of Ag to the Sn-Zn solder leads to the precipitation of ε-AgZn3 from the liquid solder on preformed interracial intermetallics （CusZn8）. The peripheral AgZn3, nodular on the Cu5Zn8 IMCs layer, is likely to be generated by a peritectic reaction L ＋ γ-Ag5Zns→AgZn3 and the following crystallization of AgZn3.

关键词： soldering materials lead-free solder wettability intermetallic compounds