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Characterization of structural and electrical properties of ZnO tetrapods 被引量:1
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作者 Yu-dong Gu Wen-jie Mai Peng Jiang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2011年第6期686-690,共5页
ZnO tetrapods were synthesized by a typical thermal vapor-solid deposition method in a horizontal tube furnace.Structural characterization was carried out by transmission electron microscopy (TEM) and select-area el... ZnO tetrapods were synthesized by a typical thermal vapor-solid deposition method in a horizontal tube furnace.Structural characterization was carried out by transmission electron microscopy (TEM) and select-area electron diffraction (SAED),which shows the presence of zinc blende nucleus in the center of tetrapods while the four branches taking hexagonal wurtzite structure.The electrical transport property of ZnO tetrapods was investigated through an in-situ nanoprobe system.The three branches of a tetrapod serve as source,drain,and "gate",respectively;while the fourth branch pointing upward works as the force trigger by vertically applying external force downward.The conductivity of each branch of ZnO-tetrapods increases 3-4 times under pressure.In such situation,the electrical current through the branches of ZnO tetrapods can be tuned by external force,and therefore a simple force sensor based on ZnO tetrapods has been demonstrated for the first time. 展开更多
关键词 zine oxide tetrapods electrical property piezoelectric materials semiconductors nanostructures
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New Evidence on the Common Ancestry of Tetrapods and Lungfish
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作者 (Zhao Baohua) 《Bulletin of the Chinese Academy of Sciences》 2002年第3期133-134,共2页
  As reported in a recent issue of Nature (Aug. 15, 2002),two Chinese scientists pinpoint their newly discovered fossil fish as the most direct piece of evi dence on the common ancestry shared by tetrapods (all land...   As reported in a recent issue of Nature (Aug. 15, 2002),two Chinese scientists pinpoint their newly discovered fossil fish as the most direct piece of evi dence on the common ancestry shared by tetrapods (all land verte brates including human beings) and lungfish. This latest advance in studying the origin and evolution of early fishes was jointly made by Professor Zhu Min from the CAS Institute of Vertebrate Paleontology & Paleoanthropology and his colleague Yu Xiaobo, now a Professor at the Biology Department of Kean University (New Jersey, USA).…… 展开更多
关键词 New Evidence on the Common Ancestry of tetrapods and Lungfish
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The morphology and histology of a juvenile Sinokannemeyeria from the Middle Triassic Ermaying Formation of Shanxi, North China
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作者 Li-juan Xie Jian Yi +3 位作者 Jian-ru Shi Zhi-shuai Kang Shi-chao Xu Run-fu Wang 《China Geology》 CAS CSCD 2023年第4期685-694,共10页
Kannemeyeriiformes were dominated tetrapods in the Middle Triassic terrestrial faunae of China.Although abundant materials of Sinokannemeyeria have been collected, their postcranial morphology information is not well ... Kannemeyeriiformes were dominated tetrapods in the Middle Triassic terrestrial faunae of China.Although abundant materials of Sinokannemeyeria have been collected, their postcranial morphology information is not well studied, especially the juveniles. This paper presents a description of an articulated Sinokannemeyeria skeleton from the Middle Triassic Ermaying Formation and reports the histological microstructure of its femur. This specimen represents a late-stage juvenile based on the histological information. For the first time, this specimen offers insights into the postcrania information of juvenile Sinokannemeyeria. 展开更多
关键词 tetrapods Sinokannemeyeria HISTOLOGY Bone microstructure Middle Triassic Geological survey engineering
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PREPARATION OF NANOMETER ZINC OXIDE BY EVAPORATION METHOD 被引量:3
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作者 A.A.A. Saleh, X.J. Zhai, Y.C. Zhai and Y. FuSchool of Materials and Metallurgy, Northeastern University, Shenyang 110004, China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2002年第6期499-504,共6页
Nanometer ZnO particles were synthesized by evaporating of zinc powders of averageparticle size of 370μm studied by XRD, TEM and electron diffraction. The particleswere formed by the oxidation of evaporated zinc vapo... Nanometer ZnO particles were synthesized by evaporating of zinc powders of averageparticle size of 370μm studied by XRD, TEM and electron diffraction. The particleswere formed by the oxidation of evaporated zinc vapor in the air. It was found that the particles range from 70 to 100nm in average particle size. The effect of experimental parameters was investigated, the increase of the air flow-rates reduced the average particle size, while increasing the evaporation temperature and the amount of metal charged increased the average particle size. TEM of the particles collected showed that the crystal habits of particles have a tetrapod-like of wurtzite structure consists of four needle crystals. It was found by electron diffraction that all particles were single crystal. 展开更多
关键词 evaporation method nanometer ZnO needle or tetrapod
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Intercalation Assembly, Characterization and Luminescent Properties of Novel Supramolecular Composite Materials, Tb(Ⅲ) Complex with Tetrapodal Ligand-Montmorillonite 被引量:3
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作者 Jiang Wei Tang Yu +2 位作者 Xu Li Liu Weisheng Tan Minyu 《Journal of Rare Earths》 SCIE EI CAS CSCD 2006年第5期537-537,共1页
Two kinds of Tb( Ⅲ ) complexes with tetrapodal ligand, [TbL(NO3)]^3+ and [TbL]^3+ (L: 1,1, 1', 1'-tera ( 2-pyridinecarboxylester )-di ( trimethylpropane)) were intercalated into the interlayer space of... Two kinds of Tb( Ⅲ ) complexes with tetrapodal ligand, [TbL(NO3)]^3+ and [TbL]^3+ (L: 1,1, 1', 1'-tera ( 2-pyridinecarboxylester )-di ( trimethylpropane)) were intercalated into the interlayer space of montmorillonite (MT) by ion exchange and coordination reaction of L with the Tb^3+ ion existing in the interlayer space of Tb-MT respectively. The obtained luminescent supramolecular composite materials, [ TbL (NO3) ]^2+-MT and [TbL]^3+-MT were characterized by elemental analysis, XRD, FT-IR, UV-vis and thermal analysis. At the same time, the luminescent properties of the materials were also studied. The results show that the intercalated materials with regular layered structure, good thermal stability and the interlayer spacing (d001) approximates to the size of the complex ions which are located in the interlayer space of MT in the form of a monolayer. 展开更多
关键词 Tb(Ⅲ) complexes with tetrapodal ligand MONTMORILLONITE supramolecular composite materials intercalation assembly luminescent properties rare earths
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Synthesis of Eu(Ⅲ) and Tb(Ⅲ) Complexes with New Aryl Amide Type Tetrapodal Ligand and Their Luminescence Properties 被引量:3
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作者 蔡正洪 谭民裕 《Journal of Rare Earths》 SCIE EI CAS CSCD 2002年第5期382-384,共3页
A new aryl amide type tetrapodal ligand L (1, 1, 1, 1 tetrakis-{[(2 benzylaminoformyl) phenoxyl]methyl}methane) and its europium and terbium nitrate complexes were synthesized. The luminescence properties of these c... A new aryl amide type tetrapodal ligand L (1, 1, 1, 1 tetrakis-{[(2 benzylaminoformyl) phenoxyl]methyl}methane) and its europium and terbium nitrate complexes were synthesized. The luminescence properties of these complexes were also studied. 展开更多
关键词 rare earths aryl amide tetrapodal ligand Eu(Ⅲ) and Tb(Ⅲ) complexes luminescence property
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Comparison of the Effect of Tetrapod Block and Armor X block on Reducing Wave Overtopping in Breakwaters 被引量:2
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作者 Omid Nourani Mehdi Behdarvandi Askar 《Open Journal of Marine Science》 2017年第4期472-484,共13页
As the Armor shape has a significant effect on the reduction of wave overtopping, this study compares the performance of various shapes of concrete armored blocks of X block and Tetrapod as the most suitable armors. I... As the Armor shape has a significant effect on the reduction of wave overtopping, this study compares the performance of various shapes of concrete armored blocks of X block and Tetrapod as the most suitable armors. In this study, a three-dimensional numerical model was used for simulation of the effects of waves on the armors of Tetrapod and X Block breakwaters. In this regard, in order to calibrate the numerical model, a sample of conventional stone armor has been selected and using available experimental data on the design of armor such as wave overtopping, wave height, period of waves and energy density of the required spectral range of wave verification was conducted on a numerical model. In this regard, it is necessary to calibrate all the conditions of the model including boundary conditions, numerical modeling, initial conditions, numerical solvers and other parameters in the numerical model and simulation error rate is determined. The maximum error of the numerical model for the relative height values of the impact waves on the structure of breakwater is 7.87% for different conditions. Accordingly, the maximum error of the numerical model in determining overtopping values is 7.81%. The average fluctuation value of overtopping in the X block armor has dropped by about 31% compared to the tetrapod armor. 展开更多
关键词 WAVE OVERTOPPING Numerical Model TETRAPOD X BLOCK Flow3D 10.1 WAVE Collision
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Experimental Study on Influencing Factors of Motion Responses for Air-Floating Tetrapod Bucket Foundation 被引量:1
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作者 LIU Xian-qing LE Cong-huan +4 位作者 ZHAO Ming-jie DING Hong-yan ZHANG Pu-yang LV Nan LUO Sheng 《China Ocean Engineering》 SCIE EI CSCD 2022年第2期258-267,共10页
Air floating transport is one of the key construction technologies of bucket foundation.The influences of draft,water depth and bucket spacing on the motion response characteristics of tetrapod bucket foundation(TBF)d... Air floating transport is one of the key construction technologies of bucket foundation.The influences of draft,water depth and bucket spacing on the motion response characteristics of tetrapod bucket foundation(TBF)during air-floating transportation were studied by models tests.The results showed that with the increase of draft,the natural periods of heave motion increased,while the maximum amplitudes of oscillating motion decreased.The maximum amplitudes of heave motion decreased while pitch motion increased with the increasing of water depth;further,the period range of oscillating amplitude close to the maximum amplitude was expanded due to shallow water effect.With increasing bucket spacing,the maximum amplitudes of heave motion first increase and then decreased,whereas the maximum amplitudes of pitch motion decreased.Therefore,the favorable air-floating transportation performance can be achieved by choosing a larger bucket spacing under the condition of meeting the design requirements and reducing the draft under shallower water. 展开更多
关键词 tetrapod bucket foundation response amplitude operator(RAO) draft water depth SPACING air-floating
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The Absorption Behavior of Tetrapod Shaped ZnO Whiskers 被引量:1
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作者 邓海 周祚万 《Journal of Modern Transportation》 1999年第2期203-208,共6页
The infrared absorption spectrum of zinc oxide whiskers with tetrapod shape was recorded and compared with ZnO powder. The absorptions of microwave and sound were investigated with a result showing that the ZnO whisk... The infrared absorption spectrum of zinc oxide whiskers with tetrapod shape was recorded and compared with ZnO powder. The absorptions of microwave and sound were investigated with a result showing that the ZnO whiskers are of excellence as absorbents of microwave and soundproofing. The results of vibration damping tests of polyvinyl chloride indicate that the material containing the tetrapod shaped ZnO whiskers appears superior damping characteristics. 展开更多
关键词 tetrapod shaped ZnO whiskers microwave absorption soundproofing vibration damping
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Placement Effect on the Stability of Tetrapod Armor Unit on Breakwaters in Irregular Waves
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作者 Yesim CELIKOGLU Demet ENGIN 《China Ocean Engineering》 SCIE EI CSCD 2017年第6期747-753,共7页
Tetrapod, one of the well-known artificial concrete units, is frequently used as an armor unit on breakwaters. Two layers of tetrapod units are normmaly placed on the breakwaters with different placement methods. In t... Tetrapod, one of the well-known artificial concrete units, is frequently used as an armor unit on breakwaters. Two layers of tetrapod units are normmaly placed on the breakwaters with different placement methods. In this study, the stability of tetrapod units with two different regularly placement methods are investigated experimentally in irregular waves. Stability coefficients of tetrapod units for both placement methods are obtained. The important characteristic wave parameters of irregular waves causing the same damage ratio as those of the regular waves are also determined. It reveals that the average of one-tenth highest wave heights within the wave train (H1/lo) causes the similar damage as regular waves. 展开更多
关键词 BREAKWATERS tetrapod unit stability placement methods irregular waves
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ZnO Planar-Tetrapod Synthesized by Cethyltrimethylamonium Hydroxide-Assisted Hydrothermal Method at Low Temperature
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作者 Sebastián López-Romero Manuel García-Hipólito +1 位作者 Mayte Saraí Valverde Labastida María de Jesús Quiroz Jiménez 《World Journal of Condensed Matter Physics》 2015年第4期339-345,共7页
Planar tetrapods ZnO (PTP-ZnO) or cross shaped tetrapod nanostructures were synthesized by a cethyltrimethylamonium hydroxide (CTAOH)-assisted hydrothermal method at low temperature (120°C). The XRD diffractogram... Planar tetrapods ZnO (PTP-ZnO) or cross shaped tetrapod nanostructures were synthesized by a cethyltrimethylamonium hydroxide (CTAOH)-assisted hydrothermal method at low temperature (120°C). The XRD diffractogram showed that the PTP-ZnO nanostructures showed a hexagonal wurtzite phase. The studies with high resolution transmission electron microscopy (HRTEM) and select area specific diffraction (SAED) revealed that the ZnO pods were single crystals and preferentially grew up along [002] direction. The growth mechanism of the CTAOH assisted-hydrothermal synthesized PTP-ZnO nanostructures is explained using the final shape guiding of materials nanostructured and surfactant-action theories. 展开更多
关键词 ZNO CTAOH SURFACTANT Assisted-Hydrothermal Technique Cross Shaped TETRAPOD
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End-Triassic nonmarine biotic events 被引量:3
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作者 Spencer G.Lucas Lawrence H.Tanner 《Journal of Palaeogeography》 SCIE CSCD 2015年第4期331-348,共18页
The Late Triassic was a prolonged interval of elevated extinction rates and low origination rates that manifested themselves in a series of extinctions during Carnian, Norian and Rhaetian time. Most of these extinctio... The Late Triassic was a prolonged interval of elevated extinction rates and low origination rates that manifested themselves in a series of extinctions during Carnian, Norian and Rhaetian time. Most of these extinctions took place in the marine realm, particularly affecting radiolarians, conodonts, bivalves, ammonoids and reef-building organisms. On land, the case for a Late Triassic mass extinction is much more tenuous and has largely focused on tetrapod vertebrates(amphibians and reptiles), though some workers advocate a sudden endTriassic(TJB) extinction of land plants. Nevertheless, an extensive literature does not identify a major extinction of land plants at the TJB, and a comprehensive review of palynological records concluded that TJB vegetation changes were non-uniform(different changes in different places), not synchronous and not indicative of a mass extinction of land plants. Claims of a substantial perturbation of plant ecology and diversity at the TJB in East Greenland are indicative of a local change in the paleoflora largely driven by lithofacies changes resulting in changing taphonomic filters. Plant extinctions at the TJB were palaeogeographically localized events, not global in extent. With new and more detailed stratigraphic data, the perceived TJB tetrapod extinction is mostly an artifact of coarse temporal resolution, the compiled correlation effect. The amphibian, archosaur and synapsid extinctions of the Late Triassic are not concentrated at the TJB, but instead occur stepwise, beginning in the Norian and extending into the Hettangian. There was a disruption of the terrestrial ecosystem across the TJB, but it was more modest than generally claimed. The ecological severity of the end-Triassic nonmarine biotic events are relatively low on the global scale. Biotic turnover at the end of the Triassic was likely driven by the CAMP(Central Atlantic Magmatic Province) eruptions, which caused significant environmental perturbations(cooling, warming, acidification) through outgassing, but the effects on the nonmarine biota appear to have been localized, transient and not catastrophic. Long-term changes in the terrestrial biota across the TJB are complex,diachronous and likely climate driven evolutionary changes in the context of fluctuating background extinction rates, not a single, sudden or mass extinction. 展开更多
关键词 Triassic-Jurassic boundary mass extinction land plants East Greenland tetrapods Newark Supergroup CAMP volcanism
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Luminescence properties of tetrapod ZnO nanostructures
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作者 王福学 蔡小龙 +2 位作者 闫大为 朱兆旻 顾晓峰 《Journal of Semiconductors》 EI CAS CSCD 2014年第6期14-18,共5页
The tetrapod ZnO nanostructures are synthesized on the Si (100) substrates using the chemical va- por deposition (CVD) method at 1000 ℃. Each nanostructure has four arms which are about 3-10 μm in length and 0.2... The tetrapod ZnO nanostructures are synthesized on the Si (100) substrates using the chemical va- por deposition (CVD) method at 1000 ℃. Each nanostructure has four arms which are about 3-10 μm in length and 0.2-1.5 μm in diameter. Further analyses on structure demonstrate that the tetrapod ZnO nanostructures have single crystalline wurtzite hexagonal structure preferentially oriented in c-axis. The photoluminescence (PL) mea- surements of the tetrapod ZnO nanostructures revealed a UV peak at 382 nm corresponding to the free exciton emission, and a green peak at 523 nm arising from deep level emission. For comparative analysis, cathodolumines- cence (CL) spectra obtained from different regions of an individual tetrapod are investigated. Moreover, a possible growth mechanism of the tetrapod ZnO nanostructures is also discussed based on the experimental results. 展开更多
关键词 ZnO TETRAPOD NANOSTRUCTURES CATHODOLUMINESCENCE PHOTOLUMINESCENCE optical properties
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Olfactory receptor gene evolution is unusually rapid across Tetrapoda and outpaces chemosensory phenotypic change
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作者 Laurel R.Yohe Matteo Fabbri +1 位作者 Michael Hanson Bhart-Anjan S.Bhullar 《Current Zoology》 SCIE CAS CSCD 2020年第5期505-514,共10页
Chemosensation is the most ubiquitous sense in animals,enacted by the products of complex gene families that detect environmental chemical cues and larger-scale sensory structures that process these cues.While there i... Chemosensation is the most ubiquitous sense in animals,enacted by the products of complex gene families that detect environmental chemical cues and larger-scale sensory structures that process these cues.While there is a general conception that olfactory receptor(OR)genes evolve rapidly,the universality of this phenomenon across vertebrates,and its magnitude,are unclear.The supposed correlation between molecular rates of chemosensory evolution and phenotypic diversity of chemosensory systems is largely untested.We combine comparative genomics and sensory morphology to test whether OR genes and olfactory phenotypic traits evolve at faster rates than other genes or traits.Using published genomes,we identified ORs in 21 tetrapods,including amphibia ns,reptiles,birds,and mammals and compared their rates of evolution to those of orthologous non-OR protein-coding genes.We found that,for all clades investigated,most OR genes evolve nearly an order of magnitude faster than other protein-coding genes,with many OR genes showing signatures of diversifying selection across nearly all taxa in this study.This rapid rate of evolution suggests that chemoreceptor genes are in "evolutionary overdrive,"perhaps evolving in response to the ever-changing chemical space of the environment.To obtain complementary morphological data,we stained whole fixed specimens with iodine,μCT-scanned the specimens,and digitally segmented chemosensory and nonchemosensory brain regions.We then estimated phenotypic variation within traits and among tetrapods.While we found considerable variation in chemosensory structures,they were no more diverse than nonchemosensory regions.We suggest chemoreceptor genes evolve quickly in reflection of an ever-changing chemical space,whereas chemosensory phe no types and processing regions are more conserved because they use a standardized or constrained architecture to receive and process a range of chemical cues. 展开更多
关键词 CHEMOSENSATION diversifying selection OLFACTION olfactory bulb olfactory receptor TETRAPOD
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