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china Foundry 2024年第5期21卷 397-408页

作者： Qi-gui Wang Andy Wang jason coryell Advanced Materials technology&Virtualization GM Global Technical CenterWarrenMI USA

Ultra-large aluminum shape castings have been increasingly used in automotive vehicles,particularly in electric vehicles for light-weighting and vehicle manufacturing cost *** most of them are structural components subject to both quasi-static,dynamic and cyclic loading,the quality and quantifiable performance of the ultra-large aluminum shape castings is critical to their success in both design and *** paper briefly reviews some application examples of ultra-large aluminum castings in automotive industry and outlines their advantages and *** affecting quality,microstructure and mechanical properties of ultra-large aluminum castings are evaluated and discussed as aluminum shape casting processing is very complex and often involves many competing mechanisms,multi-physics phenomena,and potentially large uncertainties that significantly influence the casting quality and *** analysis and mechanical property assessment of an ultra-large aluminum shape casting are *** are highlighted and suggestions are made for robust design and manufacturing of ultra-large aluminum castings.

关键词： ultra-large castings aluminum light-weighting quality microstructure materials properties

Elevated brain temperature under severe heat exposure impairs cortical motor activity and executive function

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Journal of Sport and Health Science 2024年第2期13卷 233-244页

作者： Xiang Ren tan Mary c.Stephenson Sharifah Badriyah Alhadad Kelvin W.Z.Loh tuck Wah Soong jason K.W.Lee Ivan c.c.Low Health and Social Sciences Singapore Institute of TechnologySingapore 138683Singapore Human Potential translational Research Programme Yong Loo Lin School of MedicineNational University of SingaporeSingapore 117597Singapore centre for translational Magnetic Resonance Research Yong Loo Lin School of MedicineNational University of SingaporeSingapore 117549Singapore Department of Physiology Yong Loo Lin School of MedicineNational University of SingaporeSingapore 117593Singapore Heat Resilience and Performance centre Yong Loo Lin School of MedicineNational University of SingaporeSingapore 117510Singapore N.1 Institute for Health National University of SingaporeSingapore 117456Singapore campus for Research Excellence and technological Enterprise(cREAtE) Singapore 138602Singapore

Background:Excessive heat exposure can lead to hyperthermia in humans,which impairs physical performance and disrupts cognitive *** heat is a known physiological stressor,it is unclear how severe heat stress affects brain physiology and ***:Eleven healthy participants were subjected to heat stress from prolonged exercise or warm water immersion until their rectal temperatures(t_(re))attained 39.5℃,inducing exertional or passive hyperthermia,*** a separate trial,blended ice was ingested before and during exercise as a cooling *** were compared to a control condition with seated rest(normothermic).Brain temperature(t_(br)),cerebral perfusion,and task-based brain activity were assessed using magnetic resonance imaging ***:t_(br)in motor cortex was found to be tightly regulated at rest(37.3℃±0.4℃(mean±SD))despite fluctuations in t_(re).With the development of hyperthermia,t_(br)increases and dovetails with the rising t_(re).Bilateral motor cortical activity was suppressed during high-intensity plantarflexion tasks,implying a reduced central motor drive in hyperthermic participants(t_(re)=38.5℃±0.1℃).Global gray matter perfusion and regional perfusion in sensorimotor cortex were reduced with passive *** function was poorer under a passive hyperthermic state,and this could relate to compromised visual processing as indicated by the reduced activation of left lateral-occipital ***,ingestion of blended ice before and during exercise alleviated the rise in both t_(re)and t_(bc)and mitigated heat-related neural ***:Severe heat exposure elevates t_(br),disrupts motor cortical activity and executive function,and this can lead to impairment of physical and cognitive performance.

关键词： Brain functional activity cognition Heat stress Hyperthermia Motor function

Piezoelectric resonant ice protection systems–Part1/2:Prediction of power requirement for de-icing a NAcA 0024 leading edge

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chinese Journal of Aeronautics 2024年第3期37卷 92-103页

作者： Valerian PALANQUE jason POtHIN Vale′rie POMMIER-BUDINGER Marc BUDINGER Institut clement Ader University of ToulouseINSAISAE-SUPAEROMINES ALBIUPSCNRSToulouse 31055France ISAE-SUPAERO University of Toulouse10 Avenue Edouard BelinToulouse 31055France

this paper proposes a numerical method to analyze the ice protection capability and predict the power requirements of a piezoelectric resonant de-icing *** method is based on a coupled electro-mechanical finite element analysis which enables the fast computation of the modes of resonance of interest to de-ice curved surfaces and the estimation of the input voltage and current required for a given configuration(defined by its mode,actuator location,ice deposit,etc.).Eventually,the electric power to be supplied can be also *** method is applied to a NAcA 0024 leading edge equipped with piezoelectric ***,two extension modes are analyzed and compared with respect to their efficiency and power ***,tests are carried out in an icing tunnel to verify the effectiveness of the piezoelectric ice protection system and the predictions of the maximal required *** system allows de-icing the leading edge in less than 2 s for a glaze ice deposit.

关键词： Ice protection system Piezoelectric Resonance mode Ice fracture Leading edge de-icing

Degradation and resynthesis of chlorophyll during increased oxidative stress and prolonged darkness differ between annual and perennial flax(Linum L.)

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Oil crop Science 2024年第2期9卷 121-130页

作者： Kenyon J. Nisbett Abida Alokozai Su Hyun Elizabeth Ko G. Adam Mott jason c.L. Browna Department of Biological Sciences University of Toronto ScarboroughTorontoONCanada Department of cell&Systems Biology University of TorontoTorontoONCanada centre for the Analysis of Genome Evolution&Function University of TorontoTorontoONCanada

Among plants,there is considerable variation in lifespan:annuals live less than one year,whereas perennials live for several years,with the longest-living perennial having survived 43,600 *** proposed by the Disposable Soma theory,this lifespan variation among plants likely reflects differential investment of limited energy and nutrient resources,with perennials investing more energy and nutrients into biomolecular maintenance compared to annuals in order to ensure persistence over multiple *** differential investment may be particularly important during periods of exogenous stress,which are known to accelerate biomolecular *** present study evaluated this hypothesis using annual and perennial flax(Linum L.)subjected to two exogenous stressors—increased oxidative stress(i.e.,foliar H2O2spraying)and complete prolonged *** chlorophyll has been shown to exhibit degradation in response to changes in environmental conditions,we utilized changes in chlorophyll levels during and after periods of exogenous stress to evaluate our *** predicted that i)perennials would exhibit a slower rate of chlorophyll degradation during exposure to exogenous stressors compared to annuals,and ii)perennials would exhibit a faster rate of chlorophyll resynthesis following such exposure compared to *** levels before,during,and after exposure to both exogenous stressors were measured in two separate trails,once using image colour analysis and once using *** chlorophyll degradation rates in response to oxidative stress did not differ between annuals and perennials,contrary to our predictions,chlorophyll resynthesis rates following such exposure were significantly higher in perennials,as *** plants were subjected to complete prolonged darkness,chlorophyll degradation rates were significantly lower in perennials than annuals,as predicted;however,when plants were subsequently reintroduced to natural photoperiod,ch

关键词： Ageing Life history Maximum lifespan Oxidative stress Somatic maintenance

Astrocytic calcium waves:unveiling their roles in sleep and arousal modulation

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Neural Regeneration Research 2024年第5期19卷 984-987页

作者： Erxi Wu Dan Qi Damir Nizamutdinov jason H.Huang Department of Neurosurgery and Neuroscience Institute Baylor Scott&White HealthTempleTXUSA texas A&M University School of Medicine TempleTXUSA texas A&M University School of Pharmacy College StationTXUSA LIVEStRONG cancer Institutes and Department of Oncology Dell Medical Schoolthe University of Texas at AustinAustinTXUSA Department of Neurosurgery Baylor College of MedicineTempleTXUSA

Neuron-astrocyte interactions are vital for the brain’s *** astrocyte activities is crucial for comprehending the complex neural network,particularly the population-level functions of neurons in different cortical states and associated behaviors in *** on animal sleep and wakefulness have revealed distinct cortical synchrony patterns between ***,outnumbering neurons by nearly fivefold,support and regulate neuronal and synaptic *** research on astrocyte activation during cortical state transitions has emphasized the influence of norepinephrine as a neurotransmitter and calcium waves as key components of ion channel *** summary focuses on a few recent studies investigating astrocyte-neuron interactions in mouse models during sleep,wakefulness,and arousal levels,exploring the involvement of noradrenaline signaling,ion channels,and glutamatergic signaling in different cortical *** findings highlight the significant impact of astrocytes on large-scale neuronal networks,influencing brain activity and *** astrocytic signaling pathways shows promise for treating sleep disorders and arousal *** research is needed to understand astrocytic calcium signaling in different brain regions and its implications for dysregulated brain states,requiring future human studies to comprehensively investigate neuron-astrocyte interactions and pave the way for therapeutic interventions in sleep-and arousal-related disorders.

关键词： arousal astrocyte calcium waves locus coeruleus neuron-astrocyte interaction norepinephrine sleep wakefulness

Modeling displacement flow inside a full-length casing string for well cementing

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Petroleum Research 2024年第1期9卷 1-16页

作者： Hu Dai Ali Eslami jason Schneider Gefei Liu Fred Schwering Pegasus Vertex Inc.USA Laval University Canada Sanjel Energy Services Canada Athabasca Oil corporation Canada

While computer modeling of annular displacement efficiency is widely applied in cementing engineering,modeling the displacement flow inside a casing or drill string for cementing operations has received less *** predicting displacement efficiency inside a full-length pipe is desired by cementing engineers,the attempt of developing a model with both efficiency and accuracy faces *** to computer simulators for this purpose is *** with annular flow,the displacement flow inside pipe,although within a simpler geometry and without eccentricity effect,is not simpler in physics,modelling strategy and predictability,because a variety of flow patterns and flow instabilities can develop to create complicated fluid *** this paper,we present an integrated numerical model developed to simulate displacement flows inside a full-length pipe,which connects an existing annulus model to enable complete displacement simulations of cementing *** model uses three-dimensional grid to solve fluid concentrations with degrees of mixing,and incorporates flow instability detection and flow regime *** in cementing,the model accounts for effects of pumping rate,well inclination,pipe rotation,fluid densities,rheological parameters and *** computationally efficient model does not rely on high-resolution mesh as often required by conventional computational Fluid Dynamics models,thus it is suitable to be implemented in a cementing software for daily use by well cementing *** methodology of the model is discussed in detail in this *** validate the model,we examine simulation results against experimental results obtained in our laboratory tests and cFD simulations;acceptable agreement is found under different testing *** also presented two case studies of real cementing jobs with cement evaluation logs compared to simulation results,showing that the model can predict consistent displacement efficie

关键词： Inside pipe displacement Displacement efficiency Numerical model Primary cementing Displacement flow

H_(2)mediated mixed culture microbial electrosynthesis for high titer acetate production from cO_(2)

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Environmental Science and Ecotechnology 2024年第3期19卷 125-131页

作者： Yanhong Bian Aaron Leininger Harold D.May Zhiyong jason Ren Department of civil and Environmental Engineering Princeton University86 Olden StPrincetonNJ08544United States Andlinger center for Energy and the Environment Princeton University86 Olden St.PrincetonNJ08544United States

Microbial electrosynthesis(MES)converts cO_(2)into value-added products such as volatile fatty acids(VFAs)with minimal energy use,but low production titer has limited scale-up and *** electron transfer via H_(2)on the MES cathode has shown a higher conversion rate than the direct biofilm-based approach,as it is tunable via cathode potential control and accelerates electrosynthesis from cO_(2).Here we report high acetate titers can be achieved via improved in situ H_(2)supply by nickel foam decorated carbon felt cathode in mixed community MES *** concentration of 12.5 g L^(-1)was observed in 14 days with nickel-carbon cathode at a poised potential of-0.89 V(*** hydrogen electrode,SHE),which was much higher than cathodes using stainless steel(5.2 g L^(-1))or carbon felt alone(1.7 g L^(-1))with the same projected surface area.A higher acetate concentration of 16.0 g L^(-1)in the cathode was achieved over long-term operation for 32 days,but crossover was observed in batch operation,as additional acetate(5.8 g L^(-1))was also found in the abiotic anode *** observed the low Faradaic efficiencies in acetate production,attributed to partial H_(2)utilization for *** selective acetate production with high titer demonstrated in this study shows the H_(2)-mediated electron transfer with common cathode materials carries good promise in MES development.

关键词： Microbial electrosynthesis Indirect electron transfer cO_(2)electrolysis VFAs production

Effects of length alteration of OPE-containing mono- and dinuclear alkynylplatinum(II) terpyridine complexes on photophysical, structural and morphological properties

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Nano Research 2024年第10期17卷 8893-8903页

作者： jason Koon-Lam Poon Sammual Yu-Lut Leung Eric Ka-Ho Wong Vivian Wing-Wah Yam Institute of Molecular Functional Materials State Key Laboratory of Synthetic Chemistry and Department of ChemistryThe University of Hong KongHong Kong 999077China

A series of mononuclear complexes and unsymmetric dinuclear alkynylplatinum(II)terpyridine complexes with oligo(paraphenylene ethynylene)(OPE)-derived backbone with a variation of the lengths of alkoxy chains and OPE backbones was *** morphological properties,packing lattice and gelation behaviors of the mononuclear complexes were systematically studied,and the thermodynamic parameters and packing lattices of the dinuclear complexes were also investigated,providing further insights into the roles of the non-covalent interactions and their delicate balance in constructing sophisticated supramolecular *** and nanotube formation have been observed upon a delicate control of the intermolecular interactions by altering the lengths and structural dimensions of the complexes.

关键词： supramolecular chemistry self-assembled nanostructures platinum(II)complexes metallogel

基于tROPOMI NO_(2)、cO及HcHO重构数据的近地面O_(3)浓度估算研究

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遥感学报 2024年第9期28卷 2348-2361页

作者：陈小娟秦凯 cohen jason 何秦中国矿业大学环境与测绘学院徐州221116

以tROPOMI大气成分产品为代表的卫星遥感数据在近地面臭氧(O_(3))浓度估算中表现出很好的潜力。由于云及反演算法局限性等原因,tROPOMI的大气成分产品存在一定的数据缺失,使得基于此的近地面O_(3)浓度估算数据覆盖度较低。为此,本文采... 详细信息

以tROPOMI大气成分产品为代表的卫星遥感数据在近地面臭氧(O_(3))浓度估算中表现出很好的潜力。由于云及反演算法局限性等原因,tROPOMI的大气成分产品存在一定的数据缺失,使得基于此的近地面O_(3)浓度估算数据覆盖度较低。为此,本文采用经验正交函数分解插值法(DINEOF)对tROPOMI NO_(2)、cO、HcHO原始数据产品进行缺失像元重构,并基于重构数据产品采用极限梯度提升算法(XGBoost)估算了中国大陆地区2019年—2021年高覆盖度的日最大8 h平均O_(3)浓度(MDA8 O_(3))。对比研究了DINEOF方法对tROPOMI NO_(2)、cO、HcHO原始数据产品的缺失像元进行重构后再建模估算O_(3)的方法(方案1),使用tROPOMI NO_(2)、cO、HcHO原始数据产品并对其缺失像元赋空值并输入其他特征变量来建模估算O_(3)的方法(方案2),有tROPOMI NO_(2)、cO、HcHO原始数据产品的建模结果和无tROPOMI NO_(2)、cO、HcHO原始数据产品,只有其他特征变量的建模结果相结合的方法(方案3),均可提升O_(3)模型估算结果的覆盖度。实验表明:方案1的结果最好,其十折交叉验证R^(2)=0.86,RMSE=15.86μg/m^(3),模型精度和方案2基本一致且高于方案3,在重构区域的模型精度最高(训练集R^(2)=0.82,RMSE=15.57μg/m^(3)),且当重构区域出现O_(3)重污染时(浓度大于160μg/m^(3)),能明显改善模型高值低估现象,结果的空间分布更合理。方案1估算的2019年—2021年近地面MDA8 O_(3)的平均覆盖度从33.6%提升到97.2%,使用tROPOMI NO_(2)、cO、HcHO重构数据产品建模估算O_(3)可提升模型性能和模型结果的覆盖度。

关键词：遥感近地面O_(3) tROPOMI DINEOF XGBoost 数据重构