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基于试验的单摆流固耦合作用分析

江苏科技大学学报（自然科学版） 2023年第1期37卷 98-102页

作者：马跃张安琪王山水刘平江苏科技大学土木工程与建筑学院镇江212100

为了研究结构振动时空气作用力的特征与规律,设计考虑空气作用的单摆试验.测量不同摆球半径、不同摆球质量及不同摆线长度共9种工况下的单摆位移时程曲线,通过分析单摆位移随时间的递减规律,从而计算出单摆所受空气阻力大小.对阻力值采... 详细信息

为了研究结构振动时空气作用力的特征与规律,设计考虑空气作用的单摆试验.测量不同摆球半径、不同摆球质量及不同摆线长度共9种工况下的单摆位移时程曲线,通过分析单摆位移随时间的递减规律,从而计算出单摆所受空气阻力大小.对阻力值采取两种理论计算方法-即线性阻尼(一次阻尼)与Bernoulli阻尼(二次阻尼).结合单摆的运动方程,给出了理论求解方法.通过与试验结果对比得出结论:两种阻尼方法预测与试验结果均比较接近,但是线性阻尼方法准确性更高;线性阻尼比大小与摆球面积成正比、与摆球质量成反比,而二次阻尼比大小与摆球面积成正比,与摆球质量规律不明显.

关键词：风阻力阻尼比非定常风荷载单摆试验

Improving lipid production by Rhodotorula glutinis for renewable fuel production based on machine learning

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Frontiers of Chemical Science and Engineering 2024年第5期18卷 23-35页

作者： Lihe zhang Changwei zhang Xi Zhao Changliu He Xu zhang National Energy R&D Center for Biorefinery Beijing University of Chemical TechnologyBeijing 100029China Collage of Life Science and Technology Beijing University of Chemical TechnologyBeijing 100029China Beijing Key Laboratory of Bioprocess Beijing University of Chemical TechnologyBeijing 10029China

Microbial lipid fermentation encompasses intricate complex cell growth processes and heavily relies on expert experience for optimal *** modeling of the fermentation process assists researchers in making intelligent decisions,employing logical reasoning and strategic planning to optimize lipid *** this study,the effects of medium components and concen-trations on lipid fermentation were investigated,*** then,leveraging the collated data,a variety of machine learning algorithms were used to model and optimize the lipid fermentation *** models,based on artificial neural networks and support vector machines,achieved R?values all higher than 0.93,ensuring accurate predictions of the fermentation *** linear regression was used to evaluate the respective target parameter,which were affected by the medium components of lipid ***,single and multi-objective optimiza-tion were conducted for lipid fermentation using the genetic *** results demonstrated the maximum biomass of 50.3 g·L^(-1) and maximum lipid concentration of 14.1 g:L^(-1) with the error between the experimental and predicted values less than 5%.The results of the multi-objective optimization reveal the synergistic and competitive relationship between biomass,lipid concentration,and conversion rate,which lay a basis for in-depth optimization and amplification.

关键词： microbial lipid machine learning artificial neural network support vector machine genetic algorithm

Optimising multi-vent module-based adaptive ventilation using a novel parameter for improved indoor air quality and health protection

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Building Simulation 2024年第1期17卷 113-130页

作者： Haotian zhang Xiaoxiao Ding Weirong zhang Weijia zhang Yingli Xuan Key Laboratory of Green Built Environment and Energy Efficient Technology Beijing University of TechnologyBeijing 100124China Department ofArchitecture TokyoPolytechnic UniversityTokyoJapan

As infectious respiratory diseases are highly transmissible through the air,researchers have improved traditional total volume air distribution systems to reduce infection ***-vent module-based adaptive ventilation(MAV)is a novel ventilation type that facilitates the switching of inlets and outlets to suit different indoor scenarios without changing ductwork ***,little research has evaluated MAV module sizing and air velocity selection,both related to MAV system efficiency in removing contaminants and the corresponding level of protection for occupants in the ventilated ***,the module-source offset ratio(MSOR)is proposed,based on the MAV module size and its distance from an infected occupant,to inform selection of optimal MAV module *** fluid dynamics simulations illustrated contaminant distribution in a two-person MAV equipped *** phase particles modelled respiratory contaminants from the infected occupant,and contaminant concentration distributions were compared under four MAV air distribution layouts,three air velocities,and three module sizes considered using the *** indicate that lower air velocities favour rising contaminant levels,provided the ventilation rate is *** contaminant discharge can be achieved when the line of outlets is located directly above the infected *** this parameter to guide MAV system design,85.7% of contaminants may be rendered harmless to the human body within 120 s using the default air vent layout.A more appropriate supply air velocity and air vent layout increases this value to 91.4%.These results are expected to inform the deployment of MAV systems to reduce airborne infection risk.

关键词： multi-vent module-based adaptive ventilation computational fluid dynamics indoor air quality infection control

Nanophononic metamaterials induced proximity effect in heat flux regulation

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Frontiers of physics 2024年第2期19卷 149-156页

作者： Jian zhang Haochun zhang Gang zhang School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China Institute of High Performance Computing Agency for ScienceTechnology and Research(A*STAR)Singapore 138632Singapore

Recent studies have shown that the construction of nanophononic metamaterials can reduce thermal conductivity without affecting electrical properties,making them promising in many fields of application,such as energy conversion and thermal ***,although extensive studies have been carried out on thermal conductivity reduction in nanophononic metamaterials,the local heat flux characteristic is still *** this work,we construct a heat flux regulator which includes a silicon nanofilm with silicon *** regulator has remarkable heat flux regulation ability,and various impacts on the regulation ability are ***,even in the region without nanopillars,the local heat current is still lower than that in pristine silicon nanofilms,reduced by the neighboring nanopillars through the thermal proximity *** combine the analysis of the phonon participation ratio with the intensity of localized phonon modes to provide a clear *** findings not only provide insights into the mechanisms of heat flux regulation by nanophononic metamaterials,but also will open up new research directions to control local heat flux for a broad range of applications,including heat management,thermoelectric energy conversion,thermal cloak,and thermal concentrator.

关键词： nanophononic metamaterials proximity effect

Laboratory Polysomnography Revealed the First-Night Effect in Patients with Insomnia Disorder

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Laboratory Polysomnography Revealed the First-Night Effect i...

Non-isothermal kinetics and characteristics of calcium carbide nitridation reaction with calcium-based additives

中国睡眠研究会第十四届全国学术年会

作者： Sifan Hu Jie Chen Guo Yupeng Yun Chen Sijia Lou anqi zhang Yuezhen Li Yan Shao Ping Yao Lin Lu Xiangdong Tang Hongqiang Sun Peking University Sixth Hospital Beijing Tian Tan Hospital Capital Medical University The Third Hospital of Inner Mongolia Autonomous Region West China Hospital Sichuan University

Background: Guidelines for single night versus consecutive recordings in a sleep laboratory have been disputed mainly due to being existed the first night effect. The first night effect remains a crucial issue in the studies on sleep or sleep disorders. However, these studies yielded heterogenous results. In the present study, we aimed to assess the first night effect on individuals with ***: Polysomnographic recordings in the sleep laboratory were performed for two consecutive nights among thirty-nine patients with Insomnia and age-and sex-matched to thirty-five healthy controls. Sleep variables and sleep architecture of both consecutive two nights were compared and analyzed. Sleep dairy and questionnaires focused on sleep, medical, psychological, and health history were ***: Insomnia and healthy controls demonstrated differentially poor sleep on laboratory adaptation after exposure to a new environment in the sleep lab, and found that these individuals with Insomnia was characterized by longer REM latency in the first night compared with second sleep laboratory night(p 0.05).Conclusions: The first night effect may be exhibited in Insomnia and healthy controls in a new environment, which seemed more pronounced in the healthy controls group. Patients with insomnia have relatively less change in sleep adaptation.

关键词： Insomnia disorder First-night effect REM latency Polysomnography

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Frontiers of Chemical Science and Engineering 2024年第4期18卷 49-61页

作者： Zhihan zhang Mengxiao Yu Xiaoyu zhang Jinli zhang You Han School of Chemical Engineering and Technology Tianjin UniversityTianjin 300350China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China

The nitridation reaction of calcium carbide and N_(2) at high temperatures is the key step in the production of ***,the challenges faced by this process,such as high energy consumption and poor product quality,are mainly attributed to the lack of profound understanding of the *** study aimed to improve this process by investigating the non-isothermal kinetics and reaction characteristics of calcium carbide nitridation reaction at different heating rates(10,15,20,and 30℃·min^(-1))using thermogravimetric *** kinetic equation for the nitridation reaction of additive-free calcium carbide sample was obtained by combining model-free methods and model-fitting *** effect of different calcium-based additives(CaCl_(2) and CaF_(2))on the reaction was also *** results showed that the calcium-based additives significantly reduced reaction temperature and activation energy E_(a) by about 40% with CaF_(2) and by 55%-60% with CaCl_(2).The reaction model f(α)was also changed from contracting volume(R3)to 3-D diffusion models with D3 for CaCl_(2) and D4 for CaF_(2).This study provides valuable information on the mechanism and kinetics of calcium carbide nitridation reaction and new insights into the improvement of the lime-nitrogen process using calcium-based additives.

关键词： lime-nitrogen calcium carbide calciumbased additive thermogravimetric analysis nonisothermal kinetics

Particle size spatial distribution in landslide dams

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Journal of Mountain Science 2024年第6期21卷 1886-1903页

作者： zhang Jingyi zhang Jianmin State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu 610064China

The particle composition and spatial distribution of landslide-induced dam bodies are critical geotechnical parameters for studying the hazards of dam-break ***,current research often neglects the influence of the initial particle composition and spatial distribution of the landslide on the particle composition and spatial distribution of the landslide *** study investigated the impact of initial particle size distribution,volume,and sliding length on the energy and velocity changes of characteristic particles during the sliding process and the spatial distribution of particle sizes in the landslide dam *** simulations and physical models were employed to examine the effects of sequential gradient arrangements(where particle sizes decrease from top to bottom)and four other different initial particle arrangements on the energy and velocity changes of particles and the spatial distribution of particle sizes in the dam *** study reveals the characteristics of translational and rotational energy of different particles and the laws of mechanical energy conversion,obtaining the spatial distribution patterns of particle sizes in landslide-induced *** results show that under the sequential gradient arrangement,the energy dissipation of the landslide movement is lower,with larger particles mainly distributed at the distal end and smaller particles at the proximal end of the landslide *** contrast,under the reverse gradient arrangement,the energy dissipation of the landslide movement is higher,and the distribution pattern of the dam particles is opposite to that of the sequential gradient *** the other arrangement modes,the spatial distribution of dam particles falls between the aforementioned *** is a positive correlation between particle size and translational kinetic energy within the particle flow during the landslide process,and rotational motion increases energy *** constant slope conditions,sliding

关键词： Particle size distribution Landslide Numerical simulation Discrete element method

基于“脾主为卫”探讨肠道黏膜免疫在痰湿体质调体干预中的作用机制及临床应用

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北京中医药大学学报 2023年第2期46卷 159-163页

作者：张安琪万瑾毅姚海强北京中医药大学北京100029

痰湿体质是由于水液停聚凝而成痰所致,以黏滞重浊为主要特征的体质状态,是多种代谢性疾病的共同“土壤”。“脾主为卫”是对脾脏防病祛邪功能的高度概括。“脾主为卫”的功能失调是痰湿体质者代谢紊乱的重要病理因素,然而其微观机制尚... 详细信息

痰湿体质是由于水液停聚凝而成痰所致,以黏滞重浊为主要特征的体质状态,是多种代谢性疾病的共同“土壤”。“脾主为卫”是对脾脏防病祛邪功能的高度概括。“脾主为卫”的功能失调是痰湿体质者代谢紊乱的重要病理因素,然而其微观机制尚不清晰。“脾主为卫”与肠道黏膜免疫有同质的学术内涵,从肠道黏膜免疫的角度出发,可以为中医“脾主为卫”理论作出新的科学解读。痰湿体质者存在低度慢性炎症状态,可进一步发展为胰岛素抵抗及代谢性疾病,而肠道黏膜免疫功能失调在其中发挥着重要作用。基于“脾主为卫”理论,采用中医益气健脾治法可有效调节肠道黏膜免疫,进而改善代谢紊乱,为痰湿体质的临床调体和相关疾病的治疗提供新的理论依据和治疗策略,有利于进一步指导临床应用。

关键词：中医体质痰湿体质脾主为卫肠道黏膜免疫代谢紊乱

Periodic Variation Studies of the Two Short Period W UMa-type Eclipsing Binaries: LX Lyn and V0853 Aur

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Research in Astronomy and Astrophysics 2024年第1期24卷 273-284页

作者： Xu zhang Bin zhang School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550001China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550025China

In this paper,new light curves(LCs) of contact eclipsing binary(CEB) systems LX Lyn and V0853 Aur are presented and analyzed by using the 2015 version of the Wilson-Devinney(W-D) *** order to explain their asymmetric LCs,cool starspots on the components were *** is suggested that their fill-out degrees are f=12.0%(LX Lyn) and f=26.3%(V0853 Aur).At the same time,we found that LX Lyn is a W-type eclipsing binary(EB) with an orbital inclination of i=84°.88 and a mass ratio of q=2.31.V0853 Aur is also a W-type CEB with a mass ratio of q=2.77 and an orbital inclination of i= 79°.*** on all available times of light minimum,their orbital period changes are studied by using the O-C *** O-C diagram of LX Lyn reveals a cyclic oscillation with a period of about 14.84 yr and an amplitude of 0.0019 days,which can be explained by the light-travel time effect(LTTE) due to the presence of a third body with a minimum mass of0.06M_⊙.For V0853 Aur,it is discovered that the O-C diagram of the system also shows a cyclic oscillation with a period of 9.64 yr and an amplitude of 0.03365 *** cyclic oscillation of V0853 Aur can be attributed to the LTTE by means of a third body with a mass no less than 3.77M_⊙.The third body may play an important role in the formation and evolution of these systems.

关键词： stars:activity (stars:)binaries(including multiple):close (stars:)binaries:eclipsing (stars:)brown dwarfs stars:evolution stars:formation