检索结果-南通市图书馆

Quasi-periodic variations of low energy cosmic rays

在线全文

学校读者我要写书评

暂无评论

Science China(Technological sciences) 2016年第4期59卷 547-557页

作者： KUDELA Karel SABBAH Ismail IEP SAS Kosice Slovakia Department of natural sciences College of Health Sciencesthe Public Authority for Applied Education and TrainingKuwait

Cosmic rays(CR)play an important role in space weather-related *** temporal variability,both of a quasi-periodic character as well as an irregular one,has been studied from ground-based direct measurements,as well as from cosmogenic nuclides,over a long *** attempt to describe the current knowledge of selected quasi-periodicities in CR flux in the energy range above the atmospheric threshold,from direct *** power spectrum density(PSD)of the CR time series as measured by neutron monitors(NMs)and by muon detectors has a rather complicated *** with the shape(slope)of the PSD,knowledge of the contribution of quasi-periodic variations(q-per)to the CR signal is of importance for the modulation,as well as for checking the links of CR to space weather,and/or to space climate *** rotation of the Earth and solar rotation cause two types of mechanisms behind the certain q-per observed in secondary CR on the Earth’s *** activity and solar magnetic field cyclicities contribute to the q-per signals in CR if studied over a longer *** complexity of the spatial structure of the interplanetary magnetic field(IMF)and its evolution within the heliosphere,in addition to the changes in the geomagnetic field,cause variability in contributions of the q-per in *** spectra are useful tools for checking the fine structure of q-per and their temporal *** a long time NMs and muon telescopes provide information about q-per in CR.

关键词： cosmic rays periodicities neutron monitors muon detectors

Influence of introducing Zr,Ti,Nb and Ce elements on externally solidified crystals and mechanical properties of high-pressure die-casting Al–Si alloy

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 147-153页

作者： Junjie Li Wenbo Yu Zhenyu Sun Weichen Zheng Liangwei Zhang Yanling Xue Wenning Liu Shoumei Xiong Center of Materials Science and Engineering School of Mechanical and Electronic Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Traffic&Transportation Engineering Central South UniversityChangsha 410075China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China school of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile *** can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress arouses the deformation of large integrated ***,the development of non-heat treatment Al alloys is becoming the hot *** addition,HPDC contains externally solidified crystals(ESCs),which are detrimental to the mechanical properties of *** achieve high strength and toughness of non-heat treatment die-casting Al-Si alloy,we used AlSi9Mn alloy as matrix with the introduction of Zr,Ti,Nb,and *** influences on ESCs and mechanical properties were systematically investigated through three-dimensional reconstruction and thermodynamic *** results reveal that the addition of Ti increased ESCs'size and porosity,while the introduction of Nb refined ESCs and decreased ***,large-sized Al_3(Zr,Ti)phases formed and degraded the mechanical *** introduction of Ce resulted in the poisoning effect and reduced mechanical properties.

关键词： aluminium alloy high-pressure die-casting externally solidified crystals non-heat treatment

The effect of pyrazine odor on avoidance learning and memory in wild robins Erithacus rubecula

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2011年第2期57卷 208-214页

作者： Emma C. SIDDALL Nicola M. MARPLES school of natural sciences Trinity College Dublin Dublin 2 Ireland

Toxic insects advertise their defended state to potential predators using warning displays. Frequently these displays use cues through more than one sensory modality, and combine color, smell and sound to produce a multimodal warning display. Signalling through more than one sensory pathway may enhance the rate of avoidance learning, and the memorability of the learned avoidance. A common insect warning odor, pyrazine, has previously been shown to increase the rate of learned avoidance of unpalatable yellow prey by domestic chicks （GaUus gallus domesticus）, and the odor also improved memory of this learned avoidance. However, to date no research has examined this response to pyrazine odor using wild birds under natural conditions. This study used wild robins （Erithacus rubecula） to investigate whether wild birds avoided yellow baits that smelled of pyrazine more strongly than those presented with no odor. The results provide some evidence that pyrazine odor does increase the level of protection an aposematic insect gains from a wild avian predator, but that the effect of pyrazine on learned avoidance was much weaker than was found with domestic chicks .

关键词： Aposematism Learned avoidance Memory Multimodal warning display Pyrazine Robins

Distribution and Transport of Residual Lead and Copper Along Soil Pro?les in a Mining Region of North China

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Pedosphere 2016年第6期26卷 848-860页

作者： LU Cong WU Yaoguo HU Sihai ZHANG Xiaoyan FU Yilin school of natural and applied Science Northwestern Polytechnical UniversityXi'an 710129China

Residual heavy metals are commonly considered to be immobile in soils,leading to an underestimation of their environmental *** study investigated the distribution and transport of residual heavy metals along soil pro?les,using the Xiaoqinling gold mining region in North China as a case *** samples were collected at three depths from three locations near the tailing *** speciation of copper(Cu) and lead(Pb)(exchangeable,carbonate-bound,Fe-Mn oxide-bound,organic matter-bound,and residual fractions) was determined using a sequential extraction *** residual fraction's morphology was observed using scanning electron microscopy(SEM).Results showed that metal fraction distributions along the soil pro?les were in?uenced by each fraction's *** fraction with high chemical stability can not be transformed from or into other *** led to the conclusion that the high concentration of residual metals in soils mainly resulted from residual fraction *** SEM analysis showed that ?ne particles(submicrons) were mainly attached to large particles and were likely released and transported by water?*** more sorptive fractions(non-residual fractions) were mainly retained in the top soil,and the more mobile fractions(residual fraction) were mainly leached to the deep *** and Pb concentrations in the residual fraction decreased slightly and those in the non-residual fractions decreased signi?cantly with soil *** suggest a relatively higher residual metal mobility along the soil pro?***,residual metals can be transported in soils and their environmental risk can not be ignored in assessing soil contamination.

关键词： heavy metal speciation metal concentration mobility sequential extraction soil contamination

Hear no evil： The effect of auditory warning signals on avian innate avoidance, learned avoidance and memory

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2011年第2期57卷 197-207页

作者： Emma C. SIDDALL Nicola M. MARPLES school of natural sciences Trinity College Dublin Dublin 2 Ireland

Many aposematic insect species advertise their toxicity to potential predators using olfactory and auditory signals, in addition to visual signals, to produce a multimodal warning display. The olfactory signals in these displays may have interesting effects, such as eliciting innate avoidance against novel colored prey, or improving learning and memory of defended prey. However, little is known about the effects of such ancillary signals when they are auditory rather than olfactory. The few studies that have investigated this question have provided conflicting results. The current study sought to clarify and extend understanding of the effects of prey auditory signals on avian predator responses. The domestic chick Gallus gallus domesticus was used as a model avian predator to examine how the defensive buzzing sound of a bumblebee Bombus terrestris affected the chick＇s innate avoidance behavior, and the learning and memory of prey avoidance. The results demonstrate that the buzzing sound had no effect on the predator＇s responses to unpalatable aposematically colored crumbs, suggesting that the agitated buzzing of B. terrestris may provide no additional protection from avian predators .

关键词： Aposematism Auditory signals Dietary conservatism Avoidance learning Memorability Multimodal signaling

Super-resolution morphological dissemination of intercalating dye in single DNA molecules via binding activated localization microscopy

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2018年第3期29卷 505-508页

作者： Guenyoung Park Suresh Kumar Chakkarapani Soyeong Ju Sujin Ahn Seong Ho Kang Department of Chemistry Graduate School Kyung Hee University Department of applied Chemistry and Institute of natural sciences Kyung Hee University

Fluorescent dye （YOYO-I） intercalated with single DNA molecules were investigated via bindingactivated localization microscopy （BALM） at sub-diffraction limit resolutions. Various dye-to-DNA base pair （bp） ratios were imaged using the blinking property of YOYO-1 dye under optimum BALM switching buffer conditions. Individual DNA molecules exhibited regular/irregular intercalating phenomena with respect to dye-to-DNA bp ratio. The acquired images were reconstructed into super-resolution images by applying a Gaussian fit to the centroid of the point spread function. The YOYO-1 intercalated with λ-DNA possessed a non-homogeneous region due to the different binding modes of YOYO-1 with λ-DNA. Each binding mode was imaged at the sub-diffraction limit super-resolution. The distance between homogenously localized intercalating dyes within the DNA molecules was measured to be 34nm （n= 10; dye：DNAbp= 1：100） without photocleavage in 50mmol/L β-mercaptoethylamine buffer. The results were similar to those of the theoretical values without photocleavage in the base pairs of single DNA molecules below the diffraction limit. The results paved the way for an in-depth microscopic analysis of molecular variation with single λ-DNA molecules. With this method, it should be possible to analyze the exact base pair breakdown during various stages of cell apoptosis.

关键词： λ-DNA Intercalating dye Morphological dissemination Sub-diffraction limit resolution Binding-activated localization microscopy

Dielectric-ion-conductive ZnNb2O6 layer enabling rapid desolvation and diffusion for dendrite-free Zn metal batteries

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2025年第1期100卷 693-701页

作者： Haifeng Yang Jian Wang Panpan Zhang Xiaomin Cheng Qinghua Guan Jing Dong Bixian Chen Lujie Jia Jing Zhang Yongzheng Zhang Yunjian Liu Hongzhen Lin school of Materials Science and Engineering Jiangsu University i-Lab & CAS Key Laboratory of Nanophotonic Materials and Devices Suzhou Institute of Nano-Tech and Nano-Bionics Chinese Academy of Sciences Helmholtz Institute Ulm (HIU) Karlsruhe Institute of Technology (KIT) school of Materials Science and Engineering Xi'an University of Technology State Key Laboratory of Chemical Engineering East China University of Science and Technology

Rechargeable aqueous zinc-metal batteries （AZMBs） are promising candidates for large-scale energy storage systems due to their low cost and high ***,their performance and sustainability are significantly hindered by the sluggish desolvation kinetics at the electrode/electrolyte interface and the corresponding hydrogen evolution reaction where active water molecules tightly participate in the Zn（H2O）62+solvation ***,learnt from self-generated solid electrolyte interphase （SEI） in anodes,the dielectric but ion-conductive zinc niobate nanoparticles artificial layer is constructed on metallic Zn surface （ZNB@Zn）,acting as a rapid desolvation *** zincophilic and dielectric-conductive properties of ZNB layer accelerate interfacial desolvation/diffusion and suppress surface corrosion or dendrite formation,achieving uniform Zn plating/stripping behavior,as confirmed by electronic/optical microscopies and interface spectroscopical measurements together with theoretical ***,the as-prepared ZNB@Zn electrode exhibits excellent cycling stability of over 2000 h and robust reversibility （99.54%） even under high current density and depth of discharge ***,the assembled ZNB@Zn-based full cell displays high capacity-retention rate of 80.21%after 3000 cycles at 5 A g-1and outstanding rate performance up to 10 A *** large-areal pouch cell is stabilized for hundreds of cycles,highlighting the bright prospects of the dielectric but ion-conductive layer in further application of AZMBs.

关键词： Zn metal battery Dielectric artificial layer Rapid ion diffusion Zincophilic diffusion Active water inhibition

Zircon Trace Element Constraints on the Evolution of the Paleoproterozoic Birimian Granitoids of the West African Craton(Ghana)

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Earth Science 2018年第1期29卷 43-56页

作者： Patrick Asamoah Sakyi Benxun Su Daniel Kwayisi Chen Chen Yang Bai Melesse Alemayehu Department of Earth Science School of Physical and Mathematical Sciences University of Ghana Key Laboratory of Mineral Resources Institute of Geology and Geophysics Chinese Academy of Sciences school of Earth Science University of Chinese Academy of Sciences school of applied natural Science Applied Geology Department Adama Science and Technology University

The Paleoproterozoie Birimian granitoids of the West African Craton （WAC） in the northwestern part of Ghana, have been studied for their zircon trace elements concentrations to infer the source characteristics, origin, and magmatic evolution. The zircons in the granitoids have Th/U ratios ranging from 0.03 to 1.55, and display depleted light rare earth elements 0LREE） and enriched heavy rare earth elements （HREE） contents, characterized by pronounced positive to negative anomalies of Eu （Eu/Eu＊=0.14-0.98 and 1.01-6.06, respectively） and Ce （Ce/Ce＊=0.08-0.98 and 1.02-116, respectively）, which may imply that they were derived from both magmatic and hydrothermal sources. The geochemical plots of U/Yb vs. Y and Hf, the positive correlation between Hf and the other high field strength elements 0tFSE） and high rare earth elements （REE） contents, with enrichment in Ce and depletion in Eu, indicate that the granitoids possibly formed from partial melting of the crust. The trace elements characteristics （i.e., wide range of Hf, Ce/Ce＊, Th/U and Zr/Hf values） of the zircons suggest that crystallization of the magma occurred under variable oxidation states, which spanned over a longer period, implying that our data corroborate interpretations from studies of whole-rock geochemistry and geochronology on the granitoids of northwestern Ghana. This further indicates that the evolution of the Birimian granitoids in this part of the WAC occurred earlier than what had been reported in the literature.

关键词： West African Craton granitoids zircon trace elements magmatic evolution hydro-thermal alteration.

Photodimerization and photooxygenation of 9-vinylcarbazole catalyzed by titanium dioxide and magnesium perchlorate

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2010年第3期21卷 365-368页

作者： Hajime Maeda Mio Yamamoto Hideyuki Nakagawa Kazuhiko Mizuno Division of Material sciences Graduate School of Natural Science and TechnologyKanazawa University Department of applied Chemistry Graduate School of EngineeringOsaka Prefecture University

Photoreaction of 9-vinylcarbazole in acetonitrile in the presence of titanium dioxide and a catalytic amount of magnesium perchlorate gave 3,6-di(9-carbazolyl)-1,2-dioxane as a photooxygenated product via photodimerization of *** photoreaction proceeds via an electron transfer mechanism,where magnesium perchlorate accelerated formation of the photo-oxygenated product.

关键词： Titanium dioxide Magnesium perchlorate 9-Vinylcarbazole Photooxygenation Photodimerization