检索结果-南通市图书馆

Journal of Oceanology and Limnology 2024年第2期42卷 421-438页

作者： yu’ang LIU Yifei JIANG Xiaojiang zhang zhiyuan wang yu CAO Huizan wang College of Meteorology and Oceanography National University of Defense TechnologyChangsha 410000China

The dynamic parameters for internal solitary waves(ISWs)derived from the extended Korteweg-de Vries(eKdV)equation play an important role in the understanding and prediction of *** spatiotemporal variations of the dynamic parameters of the ISWs in the northern South China Sea(SCS)were studied based on the reanalysis of long-term temperature and salinity *** results for spectrum analysis show that there are definite geographical differences for the periodic variation of the parameters:in shallow water,all parameters vary with a wave period of one year,while in deep water wave components of the parameters at other frequencies *** wavelet analysis,the wavelet power spectral densities in deep water exhibited an inter-annual variation *** example,the wave component of the dispersion coefficient with a wave period of about half a year reached its power peak once every two *** on previous work,this inter-annual variation pattern was deduced to be caused by dynamic *** further work on the regulatory mechanisms,empirical orthogonal function(EOF)decomposition was *** was found that the modes of the dispersion coefficient have different geographical distributions,explaining the reason why the wave components in different frequencies appeared in different *** numerical simulation results confirm that the variations in the parameters of the ISWs derived from the eKdV equation could affect the waveforms significantly because of changes in the polarity of the ***,the periodic variations of the dynamic parameters are related to the geographical location because of dynamic processes operating.

关键词： internal solitary waves(ISWs) dynamic parameters eKdV equation spatiotemporal variation polarity empirical orthogonal function(EOF)decomposition

Masting promotes transformation from predation to mutualism in an oak-weevil-rodent system

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2024年第7期67卷 1514-1524页

作者： hongmao zhang Hongyu Niu Michael ASteele Liqing Peng Huimin He Aoqiang Li Xianfeng Yi Hongjun Li zhibin zhang Institute of Evolution and Ecology School of Life SciencesCentral China Normal UniversityWuhan 430079China State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture Institute of ZoologyChinese Academy of SciencesBeijing 100101China Department of Biology Wilkes UniversityWilkes-Barre 18766USA School of Life Sciences Qufu Normal UniversityQufu 273165China

The significance of ecological non-monotonicity(a function whose first derivative changes signs)in shaping the structure and functions of the ecosystem has recently been recognized,but such studies involving high-order interactions are ***,we have proposed a threetrophic conceptual diagram on interactions among trees,rodents,and insects in mast and non-mast years and tested the hypothesis that oak(Quercus wutaishanica)masting could result in increased mutualism and less predation in an oak-weevil-rodent system in a warm temperate forest of *** 14-year dataset revealed that mast years coincided with a relatively low rodent abundance but a high weevil *** not only benefited seedling recruitment of oaks through increased dispersal by rodents but also a decrease in predation by rodents and weevils,as well as an increase in the overwintering survival of *** appeared to have increased weevil survival by reducing predation of infested acorns by *** results suggest that masting benefits all participants in the plant-insect-rodent system by increasing mutualism and reducing predation behavior(i.e.,a non-monotonic function).Our study highlights the significance of masting in maintaining the diversity and function of the forest ecosystem by facilitating the transformation from predation to mutualism among trophic species.

关键词： antagonism ecological non-monotonicity mutualism seed-weevil-rodent system seedling recruitment rodent overwintering survival weevil survival

Ignition processes and characteristics of charring conductive polymers with a cavity geometry in precombustion chamber for applications in micro/nano satellite hybrid rocket motors

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第2期32卷 55-66页

作者： zhiyuan zhang Hanyu Deng Wenhe Liao Bin yu Zai yu Nanjing University of Science and Technology Nanjing 210094China

The arc ignition system based on charring polymers has advantages of simple structure,low ignition power consumption and multiple ignitions,which bringing it broadly application prospect in hybrid propulsion system of micro/nano ***,charring polymers alone need a relatively high input voltage to achieve pyrolysis and ignition,which increases the burden and cost of the power system of micro/nano satellite in practical *** conductive substance into charring polymers can effectively decrease the conducting voltage which can realize low voltage and low power consumption repeated ignition of arc ignition *** this paper,a charring conductive polymer ignition grain with a cavity geometry in precombustion chamber,which is composed of PLA and multiwall carbon nanotubes(MWCNT)was *** detailed ignition processes were analyzed and two different ignition mechanisms in the cavity of charring conductive polymers were *** ignition characteristics of charring conductive polymers were also investigated at different input voltages,ignition grain structures,ignition locations and injection schemes in a visual ignition *** results demonstrated that the ignition delay and external energy required for ignition were inversely correlated with the voltages applied to ignition ***,the incremental depth of cavity shortened the ignition delay and external energy required for ignition while accelerated the propagation of *** the depth of cavity increased from 2 to 6 mm(at 50 V),the time of flame propagating out of ignition grain changed from 235.6 to 108 ms,and values of mean ignition delay time and mean external energy required for ignition decreased from 462.8 to 320 ms and 16.2 to 10.75 J,*** rear side of the cavity was the ideal ignition position which had a shorter ignition delay and a faster flame propagation speed in comparison to other ignition *** to direct injection scheme,swirlin

关键词： Micro/nano satellite hybrid propulsion Arc ignition Charring conductive polymer Ignition mechanism Ignition characteristic Repeated ignition

Soft,body conformable electronics for thermoregulation enabled by kirigami

在线全文

学校读者我要写书评

暂无评论

Bio-Design and Manufacturing 2024年第4期7卷 453-462页

作者： Lung Chow Guangyao Zhao Pengcheng wu Xingcan huang Jiyu Li Jian Li Wanying wang Guihuan Guo zhiyuan Li Jiachen wang Jingkun Zhou Yawen Yang yuyu Gao Binbin zhang Qiang zhang Dengfeng Li Ya huang Kuanming Yao Jian Lu Xinge yu Department of Biomedical Engineering City University of Hong KongHong Kong 999077China Hong Kong Centre for Cerebro-Cardiovascular Health Engineering Hong Kong 999077China Department of Biomedical Sciences City University of Hong KongHong Kong 999077China Department of Mechanical Engineering City University of Hong KongHong Kong 999077China

The application of thermoelectric devices(TEDs)for personalized thermoregulation is attractive for saving energy while balancing the quality of *** that directly attach to human skin remarkably minimized the energy wasted for cooling the entire ***,facing the extreme dynamic geometry change and strain of human skin,conventional TEDs cannot align with the contour of our bodies for the best thermoregulation ***,we designed a kirigami-based wearable TED with excellent water vapor permeability,flexibility,and *** analysis and experimental results reveal that our product can withstand various types of large mechanical deformation without circuit *** stated outcome and proposed facile approach not only reinforce the development of wearable TEDs but also offer an innovative opportunity for different electronics that require high conformability.

关键词： Thermoregulation Thermoelectric Kirigami Body conformable Wearable

Multi-blade rubbing characteristics of the shaft-disk-blade-casing system with large rotation

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 111-136页

作者： zhiyuan wu Linchuan ZHAO Han YAN Ge YAN Ao CHEN Wenming zhang State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Institute of Aerospace Systems Engineering Shanghai 201108China

Blade rubbing faults cause detrimental impact on the operation of aeroengines. Most of the existing studies on blade rubbing in the shaft-disk-blade-casing(SDBC) system have overlooked the elastic deformation of the blade, while some only consider the whirl of the rotor, neglecting its spin. To address these limitations, this paper proposes a dynamic model with large rotation for the SDBC system. The model incorporates the spin and whirl of the rotor, enabling the realistic reproduction of multiblade rubbing faults. To verify the accuracy of the SDBC model with large rotation and demonstrate its capability to effectively consider the rotational effects such as the centrifugal stiffening and gyroscopic effects, the natural characteristics and dynamic responses of the proposed model are compared with those obtained from reported research and experimental results. Furthermore, the effects of the rotating speed, contact stiffness,and blade number on the dynamic characteristics of the SDBC system with multi-blade rubbing are investigated. The results indicate that the phase angle between the rotor deflection and the unbalance excitation force increases with the increasing rotating speed,which significantly influences the rubbing penetration of each blade. The natural frequency of the SDBC system with rubbing constrain can be observed in the acceleration response of the casing and the torsional response of the shaft, and the frequency is related to the contact stiffness. Moreover, the vibration amplitude increases significantly with the product of the blade number under rubbing, and the rotating frequency approaches the natural frequency of the SDBC system. The proposed model can provide valuable insight for the fault diagnosis of rubbing in bladed rotating machinery.

关键词： shaft-disk-blade-casing(SDBC) large rotation spin and whirl multi-blade rubbing rotational effect

Antifertility effects of EP-1 (quinestrol and levonorgestrel) on Pacific rats (Rattus exulans)

在线全文

学校读者我要写书评

暂无评论

Integrative Zoology 2024年第1期19卷 127-142页

作者： Jing LIU Feiyun TU Ming LIU Jichao wang zhibin zhang Ministry of Education Key Laboratory for Ecology of Tropical Islands Key Laboratory of Tropical Animal and Plant Ecology of Hainan ProvinceCollege of Life SciencesHainan Normal UniversityHaikouHainanChina Secretariat Office International Society of Zoological Science and Society and Journal OfficeInstitute of ZoologyChinese Academy of SciencesBeijingChina State Key Laboratory of Integrated Management of Pest Insects and Rodents Institute of ZoologyChinese Academy of SciencesBeijingChina CAS Center for Excellence in Biotic Interactions University of Chinese Academy of SciencesBeijingChina

Pest rodents pose a serious threat to island *** control could be an alternative approach to control the impact of rodents on these *** this study,we examined the antifertility effects of EP-1 baits containing quinestrol(E)and levonorgestrel(P)using a dose of 50 ppm E and P at three different ratios(E:P ratio=1:2,1:1,and 2:1)on Pacific rats(Rattus exulans)in the Xisha Islands,Hainan,*** to the control group,all animals in EP-1 treatment groups showed significantly decreased food intake and body *** treated males,there were obvious abnormalities in testis structure and a significant decrease of relative seminal vesicle weight,but no significant effect on relative uterine and ovarian weights(g kg-1 body weight),or ovarian structure in *** 8%sucrose to the original 50-ppm baits(E:P ratio=1:1)significantly increased bait palatability for males and *** dose induced uterine edema and abnormalities of ovarian structure in females but had no significant negative effect on the relative testis,epididymis,and seminal vesicle weights(g kg-1 body weight)or sperm density in *** summary,50-ppm EP-1(1:1)baits have the potential to disrupt the fertility of females,and 8%sucrose addition to the EP-1 baits(E:P ratio=1:1)could improve bait *** dose disrupted the testis structure in *** studies are needed to improve bait acceptance and assess the antifertility effects of EP-1(1:1)on Pacific rats in captive breeding trials and underfield conditions.

关键词： EP-1 fertility control island biodiversity conservation levonorgestrel quinestrol Rattus exulans

Effect of expansion waves on cowl shock wave and boundary layer interaction in hypersonic inlet

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Propulsion and Power Research 2024年第1期13卷 80-97页

作者： Guangwei wu Ziao wang Teng Shi zhibin zhang Weiyu Jiang Fuxu Quan Juntao Chang Harbin Institute of Technology Harbin 150001China Xi’an Aerospace Propulsion Institute Xi’an 710100China Beijing Power Machinery Institute Beijing 100074China

The interaction of cowl shock wave and boundary layer has a crucial effect on the stability,operability and performance of hypersonic *** studies on inhibiting the sep-aration and managing the strength of the interaction of the shock wave and boundary layer with expansion corner have been ***,the expansion waves near the circular arc shoulder to effectively control the interaction and cowl shock arrangement is little ***,the interaction of the cowl shock wave and boundary layer under thefluence of the expansion waves is studied by inviscid and viscous numerical *** results reveal that the expansion waves have an important impact on the interaction between the cowl shock wave and boundary layer and the strength of shock wave,and that there are four types of inter-action processes with the change of the relative impingement positions of cowl shock *** expansion waves have a different influence on the shock wave and boundary layer inter-action at different incident *** the incident point of the cowl shock wave goes far downstream from the end of the circular arc shoulder,the influence of expansion waves is weakened,and the magnitude of separation zone ***,when the expansion waves are applied to the interaction of the cowl shock wave and boundary layer on the circular arc shoulder,the separation can be effectively *** particular,while the expansion waves interact with the shock wave and boundary layer in the back half of the circular arc shoulder,the separation is best *** with the upstream and downstream inci-dent points,the scale of separation area in the optimal control region is reduced by 65.3%at ***,the total pressure recovery coefﬁcientﬁrst increases and then decreases when the cowl moves from upstream to downstream,and the total pressure recovery coefﬁcient reaches the maximum value of 68.36%at the incident position of cowl shock wave d Z 8.09d0.

关键词： Boundary layer Expansion waves Cowl shock wave Separation Hypersonic inlet Circular arc shoulder Inviscid and viscous numerical simulations

A role for Retinoblastoma 1 in hindbrain morphogenesis by regulating GBX family

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Genetics and Genomics 2024年第9期51卷 900-910页

作者： Shuang Zhao Chen wanga Haiping Luo Feifei Li Qiang wang Jin Xu zhibin huang Wei Liu Wenqing zhang The Innovation Centre of Ministry of Education for Development and Diseases School of MedicineSouth China University of TechnologyGuangzhouGuangdong 510006China Greater Bay Biomedical Innocenter Shenzhen Bay LaboratoryShenzhenGuangdong 518055China

The hindbrain,which develops from the anterior end of the neural tube expansion,can differentiate into the metencephalon and myelencephalon,with varying sizes and *** midbrain–hindbrain boundary(MHB)and hindbrain myelencephalon/ventral midline(HMVM)are known to be the source of the progenitors for the anterior hindbrain and myelencephalon,***,the molecular networks regulating hindbrain morphogenesis in these structures remain *** this study,we show that retinoblastoma 1(rb1)is highly expressed at the MHB and HMVM in *** out rb1 in mice and zebrafish results in an enlarged hindbrain due to hindbrain neuronal *** study reveals that Rb1 controls the hindbrain morphogenesis by suppressing the expression of Gbx1/Gbx2,essential transcription factors for hindbrain development,through its binding to E2f3/Hdac1,***,we find that Gbx1 and Gbx2 are expressed in different types of hindbrain neurons,suggesting distinct roles in hindbrain *** summary,our study clarifies the specific role of RB1 in hindbrain neural cell proliferation and morphogenesis by regulating the E2f3–Gbx1 axis and the Hdac1–Gbx2 *** findings provide a research paradigm for exploring the differential proliferation of neurons in various brain regions.

关键词： Zebrafish Hindbrain Rb1 Gbx1/Gbx2 Proliferation

Numerical Analysis of the Influence of the Impinging Distance on the Scouring Efficiency of Submerged Jets

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Fluid Dynamics & Materials Processing 2024年第2期20卷 429-445页

作者： Hao Chen Xianbin Teng zhibin zhang Faxin Zhu Jie wang Zhaohao zhang School of Naval Architecture and Maritime Zhejiang Ocean UniversityZhoushan316022China School of Marine Engineering Guangzhou Maritime UniversityGuangzhou510725China

Water jet technology is widely used in submerged buried pipes as a non-traditional trenching process,often invol-ving a complex sediment *** important adjustable and inﬂuential engineering variable in this technol-ogy is represented by the impinging *** this study,the FLOW-3D software was used to simulate the jet scouring of sand beds in a submerged *** particular,four sets of experimental conditions were con-sidered to discern the relationship between the maximum scour depth and mass and the impinging *** shown by the results,a critical impinging distance h0 exists by which the static scour depth can be maximized;the scour mass ratio between dynamic and static conditions decreases as the impinging distance ***,the proﬁle contours are similar when the erosion parameter Ec is in the range 0.35

关键词： Submerged jet impinging distance numerical simulation scour depth scour proﬁle