期刊文献+
共找到1,942篇文章
< 1 2 98 >
每页显示 20 50 100
Nonlinear Time History Analysis for the Different Column Orientations under Seismic Wave Synthetic Approach
1
作者 Mo Shi Peng Wang +1 位作者 Xiaoyan Xu Yeol Choi 《World Journal of Engineering and Technology》 2024年第3期587-616,共30页
The significant impact of earthquakes on human lives and the built environment underscores the extensive human and economic losses caused by structural collapses. Over the years, researchers have focused on improving ... The significant impact of earthquakes on human lives and the built environment underscores the extensive human and economic losses caused by structural collapses. Over the years, researchers have focused on improving seismic design to mitigate earthquake-induced damages and enhance structural performance. In this study, a specific reinforced concrete (RC) frame structure at Kyungpook National University, designed for educational purposes, is analyzed as a representative case. Utilizing SAP 2000, the research conducts a nonlinear time history analysis to assess the structural performance under seismic conditions. The primary objective is to evaluate the influence of different column section designs, while maintaining identical column section areas, on structural behavior. The study employs two distinct seismic waves from Abeno (ABN) and Takatori (TKT) for the analysis, comparing the structural performance under varying seismic conditions. Key aspects examined include displacement, base shear force, base moment, joint radians, and layer displacement angle. This research is anticipated to serve as a valuable reference for seismic restraint reinforcement work on RC buildings, enriching the methods used for evaluating structures through nonlinear time history analysis based on the synthetic seismic wave approach. 展开更多
关键词 Nonlinear Time History Analysis Nonlinear Dynamic Analysis Seismic Wave Synthetic Seismic Restraint RC Frame Structure Column Orientation
下载PDF
A non-contact measurement method for rock mass discontinuity orientations by smartphone
2
作者 Kejing Chen Qinghui Jiang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第11期2892-2900,共9页
Smartphones are usually packed with a large number of features.An increasing number of researchers are paying attention to the technological capabilities of smartphones,which is a new topic and research interest.This ... Smartphones are usually packed with a large number of features.An increasing number of researchers are paying attention to the technological capabilities of smartphones,which is a new topic and research interest.This paper proposes a method using smartphones and digital photogrammetry to measure the discontinuity orientation of a rock mass.Smartphone photos satisfying a certain overlap rate provide an efficient method for generating point cloud models of rock outcrops based on image matching.Using the target and the generated point cloud model allows for determining actual geographic coordinates and the measurement of discontinuity orientations.The method proposed has been applied to two different study areas.The discontinuity orientations measured by the proposed method are compared with those measured by the manual method in two cases.The results show a good agreement,verifying the reliability and accuracy of the proposed method.The main contribution of this paper is to use knowledge of coordinate rotation to determine the actual geographic location of the model through a square target.The equipment used in this study is simple,and photogrammetric field surveys are easy to carry out. 展开更多
关键词 PHOTOGRAMMETRY Discontinuity orientation SMARTPHONE Square target Three-dimensional cloud points model
下载PDF
Evaluation of elastic-viscoplastic self-consistent models for a rolled AZ31B magnesium alloy under monotonic loading along five different material orientations and free-end torsion
3
作者 Xianyun Zhu Yuqian Wang +2 位作者 Luiz Carneiro Huamiao Wang Yanyao Jiang 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第4期1264-1275,共12页
Comprehensive experiments including monotonic tension and monotonic compression of specimens taken from a rolled AZ31B Mg thick plate along five different material orientations with respect to the rolled direction(RD)... Comprehensive experiments including monotonic tension and monotonic compression of specimens taken from a rolled AZ31B Mg thick plate along five different material orientations with respect to the rolled direction(RD),and free-end torsion of a tubular specimen machined along the thickness direction(ND)were conducted.The experimental results were used to evaluate an elastic-viscoplastic self-consistent model with the consideration of twinning and detwinning(EVPSC-TDT)on magnesium(Mg)alloys.The EVPSC-TDT model provides stress-strain curves and the hardening rates in close agreement with the experimental results of all the 11 loading cases.The model adequately predicts the textures after fracture of all the 11 loading cases and the evolutions of tension twins with increasing strains for tension in the ND,compression in the RD,and torsion along the ND.The Swift effect was observed in the experiment and was properly simulated by the model. 展开更多
关键词 Magnesium alloy Crystal plasticity TWINNING Material orientation
下载PDF
Thermal expansion behavior of sintered Nd–Fe–B magnets with different Co contents and orientations
4
作者 孟睿阳 徐吉元 +4 位作者 张家滕 刘静 方以坤 董生智 李卫 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第5期573-579,共7页
The thermal expansion behavior of sintered Nd–Fe–B magnets is a crucial parameter for production and application.However, this aspect has not been thoroughly investigated. In this study, three different sintered Nd... The thermal expansion behavior of sintered Nd–Fe–B magnets is a crucial parameter for production and application.However, this aspect has not been thoroughly investigated. In this study, three different sintered Nd–Fe–B magnets with varying Co content(Co = 0, 6, 12 wt%) were prepared using the conventional powder metallurgy method, and four magnets oriented under different magnetic fields were prepared to compare. The thermal expansion behavior for the magnets was investigated using a linear thermal dilatometry in the temperature range of 20℃–500℃. It was found that, the coefficient of thermal expansion(CTE) increases with the increase of Co contents, while the anisotropy of thermal expansion decreases.The introduction of Co leads to continuous changes from negative to positive thermal expansion in the vertically oriented direction, which is important for the development of zero thermal expansion magnets. The thermal expansion of nonoriented magnets was found to be isotropic. Additionally, the anisotropy of thermal expansion increases with the increase of orientation degree. These results have important implications for the development of sintered Nd–Fe–B with controllable CTE. 展开更多
关键词 thermal expansion sintered Nd–Fe–B magnets ORIENTATION Co content
下载PDF
A Comparative Study of the Value Orientations of Foreign Language Education Policies in China and the United States in the 21st Century
5
作者 曹迪 《海外英语》 2021年第12期278-280,共3页
Since the 21 st century, both Chinese Mainland and the United States have formulated foreign language education policiesbased on their national needs. This paper makes a comparative study of the value orientations of ... Since the 21 st century, both Chinese Mainland and the United States have formulated foreign language education policiesbased on their national needs. This paper makes a comparative study of the value orientations of foreign language education poli-cies in Chinese Mainland and the United States in the 21 st century and finds that both China and the United States have regardedtheir national interests as the essential value orientation of their foreign language education policies. To be specific,the core valueorientation of foreign language education policies in China is to enhance its cultural soft power.In contrast,the core value orienta-tion of foreign language education policies in the United States is to safeguard its national security. Through the comparison of thedifferent value orientations of foreign language education policies of the two countries, the paper provides some reference for the for-eign language education policy-making in Chinese Mainland. 展开更多
关键词 Foreign language education policies in China's Mainland Foreign language education policies in the United States Value orientations
下载PDF
A Correlation Study between Motivation Orientations and Metacognitive Strategies in English Listening
6
作者 余婷 《海外英语》 2016年第10期230-232,236,共4页
Based on learning motivation theory and metacognitive theory, the present study reports questionnaire surveys on correlation between motivation orientations and listening metacognitive strategies among 117 English maj... Based on learning motivation theory and metacognitive theory, the present study reports questionnaire surveys on correlation between motivation orientations and listening metacognitive strategies among 117 English majors. Findings suggest that: 1) English majors are mainly stimulated by instrumental motivation and show bias towards planning and evaluation strategy in listening comprehension; 2) there is a significant positive correlation between instrumental motivation and strategy of planning and evaluation; 3) significant difference between high motive group and low motive group only exists in planning and evaluation strategy. Therefore, teachers are encouraged to help students strengthen the training of listening metacognitive strategies form long-lasting motivation and promote listening proficiency as well as self-learning ability. 展开更多
关键词 MOTIVATION orientations metacognitive STRATEGIES ENGLISH LISTENING ENGLISH majors
下载PDF
Dependence of stresses on grain orientations in BCC polycrystalline films on substrates
7
作者 张建民 张研 徐可为 《Chinese Physics B》 SCIE EI CAS CSCD 2005年第9期1862-1865,共4页
Most thin films have different thermal expansion coefficients from their substrates, thus thermal stresses will be introduced into the films when the temperature is changed during annealing and service. Calculations o... Most thin films have different thermal expansion coefficients from their substrates, thus thermal stresses will be introduced into the films when the temperature is changed during annealing and service. Calculations of these stresses for grains in various crystallographic orientations have been made for seven BCC transition metals Cr, Fe, Mo, Nb, Ta, V and W. Neglecting W, which is isotropic and the stresses are equiaxial and without grain orientation (hkl) dependence, the BCC metals may be grouped into two classes. In the first class (Cr, Mo, Nb and V), the (100)-oriented grains have the largest stresses, while the stresses σ1 and σ2 in other (hkl)-oriented grains decrease linearly with the increase of the angle between (hkl) and (100), and with σ1 〈 σ2 except in (100)- and (lll)-oriented grains. In the second class (Fe and Ta), on the contrary, the (100)-oriented grains have the lowest stresses, and the stresses σ1 and σ2 in other (hkl)-oriented grains increase linearly with the increase of the angle between (hkl) and (100), and with σ1 〉 σ2 except in (100)- and (111)-oriented grains. 展开更多
关键词 BCC metals stresses grain orientations CALCULATION
下载PDF
Preferable Orientations of Interacting C_(60) Molecules inside Single Wall Boron Nitride Nanotubes
8
作者 姚震 吕佳音 +2 位作者 刘春见 吕航 刘冰冰 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第5期75-79,共5页
This work focuses on the preferable orientation analysis of the hybrid system where the C60 molecules are encap- sulated inside the boron nitride nanotubes by using the two-molecule model. The low-energy state can be ... This work focuses on the preferable orientation analysis of the hybrid system where the C60 molecules are encap- sulated inside the boron nitride nanotubes by using the two-molecule model. The low-energy state can be acquired in the contour map, which provides the visual information of the systematical van der Waals interaction potential for the C60 molecules adopting different orientations. Our results show that the C60 molecules exhibit the pre- ferred pentagon and hexagon orientations with the tube's diameter smaller and larger than 13.55A, respectively. The preferred two-bond orientation obtained in the single-molecule model is absent in this study, indicating that the intermolecular interaction of adjacent C60 molecules plays an important role in the orientational behaviors of this peapod structure. 展开更多
关键词 of on in Preferable orientations of Interacting C Molecules inside Single Wall Boron Nitride Nanotubes
下载PDF
Tartaric acid additive to enhance perovskite multiple preferential orientations for high-performance solar cells
9
作者 Zhen Wang Shuai You +5 位作者 Guanhaojie Zheng Zengguang Tang Liujiang Zhang Junhan Zhang Xiong Li Xingyu Gao 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第6期406-413,I0011,共9页
Perovskite film quality is a decisive factor governing the performance and long-term stability of perovskite solar cells(PSCs). To passivate defects for high-quality perovskite films, various additives have been explo... Perovskite film quality is a decisive factor governing the performance and long-term stability of perovskite solar cells(PSCs). To passivate defects for high-quality perovskite films, various additives have been explored in perovskite precursor with notable achievements in the development of highperformance PSCs. Herein, tartaric acid(TA) was applied as additive in perovskite precursor solution to modulate the crystal growth leading to high quality thin films with enhanced multiple preferential orientations favoring efficient charge transport along multiple directions. It is also noticed that TA can improve the energy level alignment in PSCs, which effectively accelerates both carrier extraction and transportation with non-radiative recombination suppressed at the perovskite interfaces. Based on the present perovskite films, the fabricated PSCs achieved an excellent champion power conversion efficiency(PCE) of 21.82% from that of 19.70% for the control device without TA additive. In addition, a PSC with TA additive was shown to exhibit impressive operational stability by retaining 92% of its initial PCE after~1200 h of aging at room temperature in ambient air with a relative humidity of about 10%–25%. In summary, the present work demonstrates a facile and versatile approach by using TA as additive in perovskite precursor to fabricate high quality perovskite films with enhanced multiple preferential orientations for high-efficiency stable PSCs. 展开更多
关键词 Perovskite solar cell Multiple preferential orientations Energy level alignment Tartaric acid
下载PDF
Effect of crystallographic orientations on transport properties of methylthiol-terminated permethyloligosilane molecular junction
10
作者 Ming-Lang Wang Bo-Han Zhang +3 位作者 Wen-Fei Zhang Xin-Yue Tian Guang-Ping Zhang Chuan-Kui Wang 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第7期516-523,共8页
The understanding of the influence of electrode characteristics on charge transport is essential in the field of molecular electronics.In this work,we investigate the electronic transport properties of molecular junct... The understanding of the influence of electrode characteristics on charge transport is essential in the field of molecular electronics.In this work,we investigate the electronic transport properties of molecular junctions comprising methylthiolterminated permethyloligosilanes and face-centered crystal Au/Ag electrodes with crystallographic orientations of(111)and(100),based on the ab initio quantum transport simulations.The calculations reveal that the molecular junction conductance is dominated by the electronic coupling between two interfacial metal–S bonding states,which can be tuned by varying the molecular length,metal material of the electrodes,and crystallographic orientation.As the permethyloligosilane backbone elongates,although theσconjugation increases,the decreasing of coupling induced by the increasing number of central Si atoms reduces the junction conductance.The molecular junction conductance of methylthiol-terminated permethyloligosilanes with Au electrodes is higher than that with Ag electrodes with a crystallographic orientation of(111).However,the conductance trend is reversed when the electrode crystallographic orientation varies from(111)to(100),which can be ascribed to the reversal of interfacial coupling between two metal–S interfacial states.These findings are conducive to elucidating the mechanism of molecular junctions and improving the transport properties of molecular devices by adjusting the electrode characteristics. 展开更多
关键词 molecular electronics crystallographic orientations non-equilibrium Green's function
下载PDF
Relative Molecular Orientations in Organic Optoelectronic Films Probed via Polarization-Selected UV/IR Mixed Frequency Ultrafast Spectroscopy
11
作者 Chengzhen Shen Jie Peng +4 位作者 Jianxin Guan Chuangqing Hao Zhihao Yu Hong Jiang Junrong Zheng 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2022年第1期95-103,I0013,I0014,I0063,共12页
Molecular packing patterns are crucial factors determining electron/energy transfer processes that are critical for the optoelectronic properties of organic thin film devices.Herein,the polarization-selective ultravio... Molecular packing patterns are crucial factors determining electron/energy transfer processes that are critical for the optoelectronic properties of organic thin film devices.Herein,the polarization-selective ultraviolet/infrared(UV/IR)mixed frequency ultrafast spectroscopy is applied to investigate the relative molecular orientations in two organic thin films of 7-(diethylamino)coumarin-3-carboxylic acid(DEAC)and perylene.The signal anisotropy changes caused by intermolecular energy/electron transfers are utilized to calculate the cross angles between the electronic transition dipole moment of the donor and the vibrational transition dipole moments of the acceptor,yielding the relative orientation between two adjacent molecules.Using this method,the relative orientation angle in DEAC film is determined to be 53.4°,close to 60°of its single crystalline structure,and that of the perylene film is determined to be 6.2°,also close to-0.2°of its single crystalline structure.Besides experimental uncertainties,the small difference between the angles determined by this method and those of single crystals also results from the fact that the thin film samples are polycrystalline where some of the molecules are amorphous. 展开更多
关键词 OPTOELECTRONICS Relative molecular orientations Organic films
下载PDF
Studying the Orientations of Luxor Ancient Egyptian Temples Using QuickBird Images
12
作者 Mosalam Shaitout 《Journal of Earth Science and Engineering》 2014年第4期210-226,共17页
Ancient Egyptians change the orientation of their temples from True East (during the old kingdom) to the Winter Solstice (during the new kingdom), because of the cultic change from a rather pure solar to a mixed s... Ancient Egyptians change the orientation of their temples from True East (during the old kingdom) to the Winter Solstice (during the new kingdom), because of the cultic change from a rather pure solar to a mixed solar religion (R^a to Amfin-R^a). The traditional methods for measuring the orientations and alignment, the axis of ancient Egyptian constructions like field survey are usually time consuming and costly. Remote sensing techniques are becoming powerful tools for archaeologists in their discovery and exploration ancient sites. Many researchers have considered very high resolution sensors, especially IKONOS with 1.0 m resolution, QuickBird with 0.61 m resolution and Geoeye-1 with 0.50 m resolutions as possible substitutes of the classical aerial photos used for multi purposes such as cartographic at large scales. Research objectives is to establish a practical methodology for calculation the orientation of the main axis of the ancient Egyptian temple based on very high resolution QuickBird images as alternative for traditional methods. Five sites have been selected to perform our research lies in Luxor city, Egypt: Luxor, Karnak, Hatshepsut, Ramesseum temples and Madinat Habu. Analysis of the obtained results has been done to explain the type of orientation of Luxor temples. Previous archaeologist's studies classified the orientation of ancient Egyptians constructions into astronomical orientation (solar, moon and stars) or topographical orientation (Nile direction and hills) or both. A comparative study has been done between the results obtained from traditional methods (field survey and Google Earth images) and from very high resolution QuickBird satellite images. From the obtained results, error in the main axis azimuth of Luxor, Karnak, Madinat Habu, Hatshepsut and Ramesseum temples range about minutes of are. One can concluded that using VHR (Very High Resolution) QuickBird satellite images in calculation the azimuth of ancient sites is the accurate method. 展开更多
关键词 orientations ancient sites QuickBird images ARCHAEOLOGY VHR satellite images.
下载PDF
Laser Polarization Orientations in(e,2e)Reactions in Atoms
13
作者 Ajana I. Makhoute A. Khalil D. 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第8期62-65,共4页
Second-order Born calculations are performed to investigate the triple differential cross sections of coplanar asymmetric laser-assisted (e, 2e) collisions for hydrogen and helium targets. The incident electron is c... Second-order Born calculations are performed to investigate the triple differential cross sections of coplanar asymmetric laser-assisted (e, 2e) collisions for hydrogen and helium targets. The incident electron is considered to be dressed by the laser field in a nonperturbative manner by choosing the Volkov solutions in both the initial and final channels. Detailed calculations of the scattering amplitudes are performed using the Sturmian basis expansion. The state of the ejected electron is described by a Coulomb-Volkov wave function. Two geometries are investigated in which the laser polarization vector is either parallel to the incident momentum of the projectile or parallel to the momentum transfer. Our numerical results show that, in the low energy range, these two laser polarization orientations give the same shape and the same order of magnitude of laser-assisted ionization cross sections of helium and hydrogen targets. 展开更多
关键词 Laser Polarization orientations in e 2e)Reactions in Atoms
下载PDF
Integrative and Instrumental Motivational Orientations of English Language Learning
14
作者 杨忱翯 《海外英语》 2019年第8期98-99,共2页
As a key predictor of learners’language achievement,motivation has long been an active research area in second language acquisition.Among assorted theories,Gardner’s perspective is one of the foundations of L2 motiv... As a key predictor of learners’language achievement,motivation has long been an active research area in second language acquisition.Among assorted theories,Gardner’s perspective is one of the foundations of L2 motivation research and thus has dominated this field for a long time.Do?rnye later put forward the L2 Motivational Self System to reconceptualise Gardner’s notions.The current essay attempts to reflect on the concepts of integrative and instrumental motivational orientations discussed in both Gardner’s and Do?rnyei’s theoretical frameworks in order to gain a subtler understanding of the role of these two notions in L2 motivation. 展开更多
关键词 motivational orientations ENGLISH learning SECOND LANGUAGE ACQUISITION
下载PDF
Coverage-dependent Orientations of Dy@C82 Molecules on Au(111) Surface
15
作者 陈凤云 胡振芃 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2012年第4期423-428,I0003,共7页
The adsorption and molecular orientation of Dy@Cs2 isomer I on Au(111) has been investigated using ultrahigh-vacuum scanning tunneling microscopy at 80 K. At low coverages, the Dy@Cs2 molecules tend to grow along th... The adsorption and molecular orientation of Dy@Cs2 isomer I on Au(111) has been investigated using ultrahigh-vacuum scanning tunneling microscopy at 80 K. At low coverages, the Dy@Cs2 molecules tend to grow along the step edges of Au(111), forming small clusters and molecular chains. Adsorption of Dy@Cs2 on the edges is dominated by the fullerene-substrate interaction and presents various molecular orientations. At higher coverages, the Dy@Cs2 is found to form ordered islands consisting of small domains of equally oriented molecules. The Dy@Cs2 molecules in the islands prefer the adsorption configurations with the major C2 axis being approximately parallel to the surface of the substrate. Three preferable orientations of the Dy@Cs2 molecules are found in a two-dimensional hexagonal close packed overlayer. These observations are attributed to the interplay of the fullerene-substrate interaction and dipole-dipole interaction between the metallofullerenes. 展开更多
关键词 Endohedral metallofullerene Scanning tunneling microscopy Molecular orientation MONOLAYER
下载PDF
Effect of varying spatial orientations on build time requirements for FDM process: A case study 被引量:1
16
作者 Sandeep Rathee Manu Srivastava +1 位作者 Sachin Maheshwari Arshad Noor Siddiquee 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2017年第2期92-100,共9页
In this research, effect of varying spatial orientations on the build time requirements for fused deposition modelling process is studied. Constructive solid geometry cylindrical primitive is taken as work piece and m... In this research, effect of varying spatial orientations on the build time requirements for fused deposition modelling process is studied. Constructive solid geometry cylindrical primitive is taken as work piece and modeling is accomplished for it. Response surface methodology is used to design the experiments and obtain statistical models for build time requirements corresponding to different orientations of the given primitive in modeller build volume. Contour width, air gap, slice height, raster width, raster angle and angle of orientation are treated as process parameters. Percentage contribution of individual process parameter is found to change for build time corresponding to different spatial orientations. Also, the average of build time requirement changes with spatial orientation. This paper attempts to clearly discuss and describe the observations with an aim to develop a clear understanding of effect of spatial variations on the build time for Fused Deposition Modelling process. This work is an integral part of process layout optimization and these results can effectively aid designers specially while tackling nesting issues. 展开更多
关键词 FUSED deposition modeling Spatial orientation PROCESS parameters Response Surface Methodology BUILD TIME
下载PDF
Effect of crystal orientations and precipitates on corrosion behavior of Al-Cu-Li single crystals 被引量:1
17
作者 Feng WEN Ji-qiang CHEN +5 位作者 Shuang HAN Zi-xiang ZHOU Shi-biao ZHONG Ying-hui ZHANG Wei-rong LI Ren-guo GUAN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第12期3887-3900,共14页
The effect of the crystal orientations and precipitates on the corrosion behavior of Al-Cu-Li single crystals was studied by scanning electron microscopy, transmission electron microscopy, optical microscopy, immersio... The effect of the crystal orientations and precipitates on the corrosion behavior of Al-Cu-Li single crystals was studied by scanning electron microscopy, transmission electron microscopy, optical microscopy, immersion testing in exfoliation corrosion solution, and electrochemical testing. The results show that the corrosion rates of different orientations of the aged Al-Cu-Li alloy increase in the order of (001) 1 phase deteriorated the corrosion resistance of the Al-Cu-Li alloy, and the degree of deterioration differed in different crystal plane orientations. The severe localized corrosion of the aged alloy propagates along the crystallography and extends along the {111}Alplane in the form of corrosion bands. 展开更多
关键词 aluminum alloys single crystal corrosion crystal orientation PRECIPITATES
下载PDF
Preferred orientations of encapsulated C_(60) molecules inside single wall carbon nanotubes
18
作者 姚震 刘然 +5 位作者 马凤仙 路双臣 田夫波 段德芳 崔田 刘冰冰 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第7期369-376,共8页
A systematical study of the orientational behavior of C60 molecules in single wall carbon nanotubes (SWCNTs) with different chirality and diameter has been performed by using a model of an infinite long nanotube fil... A systematical study of the orientational behavior of C60 molecules in single wall carbon nanotubes (SWCNTs) with different chirality and diameter has been performed by using a model of an infinite long nanotube filled with two C60 (denoted as C60-1 and C60-2) molecules. We studied the preferred orientation of the C60-1 molecule when the neighboring C60-2 molecule was fixed at the pentagon, double-bond, and hexagon orientations respectively. Our results showed that the C60-1 molecule prefers the pentagon (hexagon) orientation when the tube diameter is smaller (larger) than 1.31nm (1.36nm). For the tube diameter in between, the preferred molecular orientation of C60-1 changes from pentagon to hexagon with the increasing tube diameter when the neighboring C60-2 molecule is fixed at the pentagon or double-bond orientation. A novel vertex orientation for the C60-1 molecule has been found when the C60-2 molecule is fixed at the hexagon orientation. 展开更多
关键词 peapod C60 NANOTUBE orientation
下载PDF
Orientations of Rare-earth-containing Heteropolyoxometalates with Different Sizes in the Interlayer of Synthetic Multibilayer Films
19
作者 Yong Hui WANG Xin Long WANG +1 位作者 Chang Wen HU En Bo WANG 《Chinese Chemical Letters》 SCIE CAS CSCD 2002年第9期887-890,共4页
Three rare-earth-containing heteropolyoxometalates with different sizes, Na9[Eu(W5 O18)2], K13[Eu(SiW11O39)2], and K17[Eu(P2W17O61)2], have been incorporated by self-assembly into the interlayer of synthetic multibila... Three rare-earth-containing heteropolyoxometalates with different sizes, Na9[Eu(W5 O18)2], K13[Eu(SiW11O39)2], and K17[Eu(P2W17O61)2], have been incorporated by self-assembly into the interlayer of synthetic multibilayer films of dimethyldioctadecylammonium chloride and exhibited different orientations. 展开更多
关键词 Rare-earth-containing heteropolyoxometalate synthetic multibilayer film DODA orientation.
下载PDF
Behaviours in Attachment-Detachment Cycles of Geckos in Response to Inclines and Locomotion Orientations
20
作者 Weijia ZONG Zhouyi WANG +3 位作者 Bingcheng WANG Zhourong ZHANG Chang YIN Zhendong DAI 《Asian Herpetological Research》 SCIE CSCD 2022年第2期125-136,共12页
Geckos can move quickly in various environments by efficiently controlling their complex adhesive toe pads.The locomotion behaviours observed in the attachment-detachment(A-D)cycle of their toe pads in response to cha... Geckos can move quickly in various environments by efficiently controlling their complex adhesive toe pads.The locomotion behaviours observed in the attachment-detachment(A-D)cycle of their toe pads in response to changes in their environment should be studied to understand the adaptive behavioural characteristics of such toe pads.The lack of systematic research on the entire A-D cycle,including the release,swing,contact,and adhesion stages,limits the comprehension of the adhesive locomotion mechanism.The A-D cycle of Gekko gecko that facilitates the foot locomotion on inclined and vertical surfaces was investigated to clarify the locomotion behaviours in different stages.Results show that the change trends of foot locomotor angles(yaw and pitch)during the entire A-D cycle remain unchanged in response to various substrates.The bending angles(fore 41°;hind 51°)and contact time percentages(fore 7.42%;hind 7.44%)in the contact stage as well as the forefoot angle ranges(yaw:163.09°;pitch:308.68°)in the A-D cycle also remain constant across all substrates.These invariant foot locomotion behaviours during the swing and contact stages suggest that the foot behaviours are weakly related to the forces acting on the foot,which change according to the environment.Furthermore,the forefoot and hindfoot have different anatomical structure and functional demands,thus,the angle range of forefoot locomotion is larger than that of hindfoot locomotion,and the pitch angle change trend of the forefoot is opposite to that of the hindfoot.The diverse and complex locomotion control of the adhesive toe pads for various environments is reduced by the consistent behaviours in the gecko’s A-D cycle,such as the constant postures in the swing and contact stages.This study provides insight into the adhesive locomotion mechanism of geckos and can facilitate further research on the effective design and control of adhesion robots. 展开更多
关键词 attachment-detachment cycle Gekko gecko inclines locomotion behaviours locomotion orientation
下载PDF
上一页 1 2 98 下一页 到第
使用帮助 返回顶部