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Learning Sequential and Structural Dependencies Between Nucleotides for RNA N6-Methyladenosine Site Identification
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作者 Guodong Li Bowei Zhao +4 位作者 Xiaorui Su Dongxu Li Yue Yang Zhi Zeng Lun Hu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第10期2123-2134,共12页
N6-methyladenosine(m6A)is an important RNA methylation modification involved in regulating diverse biological processes across multiple species.Hence,the identification of m6A modification sites provides valuable insi... N6-methyladenosine(m6A)is an important RNA methylation modification involved in regulating diverse biological processes across multiple species.Hence,the identification of m6A modification sites provides valuable insight into the biological mechanisms of complex diseases at the post-transcriptional level.Although a variety of identification algorithms have been proposed recently,most of them capture the features of m6A modification sites by focusing on the sequential dependencies of nucleotides at different positions in RNA sequences,while ignoring the structural dependencies of nucleotides in their threedimensional structures.To overcome this issue,we propose a cross-species end-to-end deep learning model,namely CR-NSSD,which conduct a cross-domain representation learning process integrating nucleotide structural and sequential dependencies for RNA m6A site identification.Specifically,CR-NSSD first obtains the pre-coded representations of RNA sequences by incorporating the position information into single-nucleotide states with chaos game representation theory.It then constructs a crossdomain reconstruction encoder to learn the sequential and structural dependencies between nucleotides.By minimizing the reconstruction and binary cross-entropy losses,CR-NSSD is trained to complete the task of m6A site identification.Extensive experiments have demonstrated the promising performance of CR-NSSD by comparing it with several state-of-the-art m6A identification algorithms.Moreover,the results of cross-species prediction indicate that the integration of sequential and structural dependencies allows CR-NSSD to capture general features of m6A modification sites among different species,thus improving the accuracy of cross-species identification. 展开更多
关键词 Cross-domain reconstruction cross-species prediction N6-methyladenosine(m6A)modification site RNA sequence sequential and structural dependencies
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Effects of Salt Stress on Anatomical Structure of Leaves of Malus sieversii and Malus robusta 被引量:2
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作者 马兰 吴玉霞 何天明 《Agricultural Science & Technology》 CAS 2016年第8期1777-1779,1785,共4页
[Objective] This study was conducted to compare leaf anatomical structure of Malus sieversii and M. robusta under different salt concentration levels to determine their tolerance to salt and thus to provide rootstock ... [Objective] This study was conducted to compare leaf anatomical structure of Malus sieversii and M. robusta under different salt concentration levels to determine their tolerance to salt and thus to provide rootstock materials for apple production in salinized soil in Southern Xinjiang. [Method] The experiment was conducted with M. sieversii and M. robusta as test materials. Salt stress was simulated using 8 g/L of NaCI solution, and Hoagland nutrient solution was used instead of NaCI solution as control group (CK). Samples were collected on the 20^th d of treatment, sliced through paraffin processing. The prepared paraffin sections of M. sieversii and M. robusta were then observed under a light microscope for anatomical structures of leaf, upper epidermis, lower epidermis, palisade tissue and spongy tissue. [Result] Compared with the control, the leaf, upper epidermis, lower epidermis and spongy tissue of M. sieversii and M. robusta under salt stress were thickened at different degrees, while the thickness of the palisade tissue was decreased. Moreover, high salt concentration caused severer damage to the cell structure of M. sieversii than to that of M. robusta, as M. robusta cells maintained better structural integrity. [Conclusion] M. robusta has higher adaptability to salt stress than M. sieversii. 展开更多
关键词 NaCl stress m. sieversii m. robusta Leaf anatomical structure
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An Overview of the Multi-Band and the Generalized BCS Equations-Based Approaches to Deal with Hetero-Structured Superconductors
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作者 G. P. Malik 《Open Journal of Microphysics》 2018年第2期7-13,共7页
We trace the conceptual basis of the Multi-Band Approach (MBA) and recall the reasons for its wide following for composite superconductors (SCs). Attention is then drawn to a feature that MBA ignores: the possibility ... We trace the conceptual basis of the Multi-Band Approach (MBA) and recall the reasons for its wide following for composite superconductors (SCs). Attention is then drawn to a feature that MBA ignores: the possibility that electrons in such an SC may also be bound via simultaneous exchanges of quanta with more than one ion-species—a lacuna which is addressed by the Generalized BCS Equations (GBCSEs). Based on several papers, we give a concise account of how this approach: 1) despite employing a single band, meets the criteria satisfied by MBA because a) GBCSEs are derived from a temperature-incorporated Bethe-Salpeter Equation the kernel of which is taken to be a “superpropagator” for a composite SC-each ion-species of which is distinguished by its own Debye temperature and interaction parameter and b) the band overlapping the Fermi surface is allowed to be of variable width. GBCSEs so-obtained reduce to the usual equations for the Tc and Δ of an elemental SC in the limit superpropagator → 1-phonon propagator;2) accommodates moving Cooper pairs and thereby extends the scope of the original BCS theory which restricts the Hamiltonian at the outset to terms that correspond to pairs having zero centre-of-mass momentum. One can now derive an equation for the critical current density (j0) of a composite SC at T = 0 in terms of the Debye temperatures of its ions and their interaction parameters— parameters that also determine its Tc and Δs;3) transforms the problem of optimizing j0 of a composite SC, and hence its Tc, into a problem of chemical engineering;4) provides a common canopy for most composite SCs, including those that are usually regarded as outside the purview of the BCS theory and have therefore been called “exceptional”, e.g., the heavy-fermion SCs;5) incorporates s±-wave superconductivity as an in-built feature and can therefore deal with the iron-based SCs, and 6) leads to presumably verifiable predictions for the values of some relevant parameters, e.g., the effective mass of electrons, for the SCs for which it has been employed. 展开更多
关键词 Hetero-structured SUPERCONDUCTORS mULTI-BAND and Generalized bcS Equations-Based APPROACHES Unified Treatment of Cuprates and Fe-Based SUPERCONDUCTORS Quest for Clues about Raising Tc
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基于双端Mach-Zehnder的电缆舞动监测系统设计
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作者 衣文索 寇汉鹏 +3 位作者 聂大禹 冯振华 陈学峰 王普莫 《吉林大学学报(理学版)》 CAS 北大核心 2024年第5期1248-1253,共6页
针对传统电缆舞动检测器在面对电磁干扰和持续供电时灵敏度低、信噪比差、安装复杂和需额外供电等问题,提出一种新型双端Mach-Zehnder(M-Z)电缆扰动监测系统.该系统采用双端光纤M-Z光路结构,可实现长距离、大尺度、多维度的在线监测和... 针对传统电缆舞动检测器在面对电磁干扰和持续供电时灵敏度低、信噪比差、安装复杂和需额外供电等问题,提出一种新型双端Mach-Zehnder(M-Z)电缆扰动监测系统.该系统采用双端光纤M-Z光路结构,可实现长距离、大尺度、多维度的在线监测和结构安全预警,从而实时定位舞动位置.该系统的检波器力学单元采用硅胶弹性体和黄铜质量块推挽式结构,经ANSYS软件进行参数化建模和有限元分析后,得出其固有频率为106.77 Hz,与实验所测数据的相对误差仅为1.65%.实验结果表明,该检测器在0~140 Hz内的相对灵敏度为41.25~66.78 dB (rad/Pa),对舞动信号具有较高灵敏度的检测能力. 展开更多
关键词 m-Z干涉仪 光纤传感 推挽式结构 有限元分析
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Disbond detection with piezoelectric wafer active sensors in RC structures strengthened with FRP composite overlays 被引量:2
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作者 Victor Giurgiutiu Kent Harries +2 位作者 Michael Petrou Joel Bost Josh B.Quattlebaum 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2003年第2期213-223,共11页
The capability of embedded piezoelectric wafer active sensors(PWAS)to perform in-situ nondestructive evaluation(NDE)for structural health monitoring(SHM)of reinforced concrete(RC)structures strengthened with fiber rei... The capability of embedded piezoelectric wafer active sensors(PWAS)to perform in-situ nondestructive evaluation(NDE)for structural health monitoring(SHM)of reinforced concrete(RC)structures strengthened with fiber reinforced polymer(FRP)composite overlays is explored.First,the disbond detection method were developed on coupon specimens consisting of concrete blocks covered with an FRP composite layer.It was found that the presence of a disbond crack drastically changes the electromecfianical(E/M)impedance spectrum lneasurcd at the PWAS terlninals.The spectral changes depend on the distance between the PWAS and the crack tip.Second,large scale experiments were conducted on a RC beam strengthened with carbon fiber reinforced polymer(CFRP)composite overlay.The beam was subject to an accelerated fatigue load regime in a three-point bending configuration up to a total of 807,415 cycles.During these fatigue tests,the CFRP overlay experienced disbonding beginning at about 500,000 cycles.The PWAS were able to detect the disbonding before it could be reliably seen by visual inspection.Good correlation between the PWAS readings and the position and extent of disbond damage was observed.These preliminary results demonstrate the potential of PWAS technology for SHM of RC structures strengthened with FRP composite overlays. 展开更多
关键词 FRP composite overlays composite strengthening and rehabilitation structural health monitoring piezoelectric wafer active sensors E/m impedance aging infrastructure disbond damage PWAS
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Edge Structure of Reynolds Stress and Poloidal Flow on the HL-1M Tokamak 被引量:6
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作者 洪文玉 王恩耀 +2 位作者 曹建勇 李强 刘达致 《Plasma Science and Technology》 SCIE EI CAS CSCD 2001年第3期791-796,共6页
The measurement on radial profile of electrostatic Reynolds stress, plasma poloidal rotations, radial and poloidal electric field have been performed in the plasma boundary region of the HL-IM Tokamak using a multi-ar... The measurement on radial profile of electrostatic Reynolds stress, plasma poloidal rotations, radial and poloidal electric field have been performed in the plasma boundary region of the HL-IM Tokamak using a multi-array of Mach/Langmuir probes. In the experiments of Lower Hybrid Current Drive (LHCD), Supersonic Molecular Beam injection (SMBI), Multi-shot Pellet Injection (MPI) and Neutral Beam injection (NBI), the correlation between the Reynolds stress and poloidal flow in the edge plasma is presented. The results indicate that a sheared poloidal flow can be generated in Tokamak plasma due to radially varying Reynolds stress. 展开更多
关键词 LHCD Edge structure of Reynolds Stress and Poloidal Flow on the HL-1m Tokamak HL
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一种Deoxys-BC算法的中间相遇攻击方法
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作者 李征 李曼曼 陈少真 《计算机科学》 CSCD 北大核心 2024年第2期378-386,共9页
Deoxys-BC密码算法是在2014年亚密会上发布的一种轻量级可调分组密码算法,该算法的设计采用SPN结构和TWEAK框架。通过研究Deoxys-BC密码算法的内部特征与密钥扩展的特点,利用控制调柄差分的方法,并结合差分枚举技术和轮密钥调柄差分叠... Deoxys-BC密码算法是在2014年亚密会上发布的一种轻量级可调分组密码算法,该算法的设计采用SPN结构和TWEAK框架。通过研究Deoxys-BC密码算法的内部特征与密钥扩展的特点,利用控制调柄差分的方法,并结合差分枚举技术和轮密钥调柄差分叠加消除特性,构造6轮Deoxys-BC-256和7轮Deoxys-BC-384的中间相遇区分器。利用此区分器,通过减少猜测的字节量,来达到降低复杂度的效果,改进了9轮Deoxys-BC-256和11轮Deoxys-BC-384中间相遇攻击的结果。相比Deoxys-BC系列密码算法现有的中间相遇攻击结果,该攻击的时间复杂度和存储复杂度均大幅下降。 展开更多
关键词 分组密码 Deoxys-bc SPN结构 中间相遇攻击 差分枚举
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Structure and Redox Properties of VCe_(0.95)M_(0.05) (M=Cu, Co, Mn, Fe and Cr) Mixed Oxides 被引量:1
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作者 钟依均 罗孟飞 《Journal of Rare Earths》 SCIE EI CAS CSCD 2002年第4期325-328,共4页
The mixed oxides, VCe and VCe 0.95M 0.05 (M=Cu, Co, Mn, Fe and Cr), were prepared by sol-gel method. The structure and redox properties of these mixed oxides were characterized by XRD, Raman, XPS and TPR techniq... The mixed oxides, VCe and VCe 0.95M 0.05 (M=Cu, Co, Mn, Fe and Cr), were prepared by sol-gel method. The structure and redox properties of these mixed oxides were characterized by XRD, Raman, XPS and TPR techniques. The main phase is tetragonal VCeO 4 phase in all samples. The substitution of Fe, Mn, Cu or Co for Ce results in the formation of CeO 2 or monoclinic VCeO 4 phase. The XPS result indicates that valence of V is +5+δ(δ<1) in VCe 0.95Co 0.05, VCe 0.95Mn 0.05, VCe 0.95Cr 0.05 and VCe 0.95Fe 0.05 samples compared with VCe , on the contrary, valence of V is +5-δ (δ<1) in VCe 0.95Cu 0.05 sample. The Fe, Co, Cr and Mn enhance the reduction of V 5+ in VCeO 4, whereas Cu inhibits this reduction. 展开更多
关键词 rare earths VCe 0.95m 0.05 redox structure
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硅溶胶包覆制备核壳结构VO_(2)(M)@SiO_(2)研究
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作者 雷心瑜 孙恒辉 +3 位作者 袁新强 张伟 蒋鹏 张立斋 《无机盐工业》 CAS CSCD 北大核心 2024年第6期46-54,共9页
通过SiO_(2)包覆VO_(2)(M)材料形成核壳结构,可以显著提高其可见光透过率(T_(lum)),有效减缓VO_(2)(M)的氧化过程,对于增强智能窗的应用价值具有重要意义。Stöber法是制备核壳结构VO_(2)(M)@SiO_(2)的传统方法,采用硅溶胶凝胶法来... 通过SiO_(2)包覆VO_(2)(M)材料形成核壳结构,可以显著提高其可见光透过率(T_(lum)),有效减缓VO_(2)(M)的氧化过程,对于增强智能窗的应用价值具有重要意义。Stöber法是制备核壳结构VO_(2)(M)@SiO_(2)的传统方法,采用硅溶胶凝胶法来简化制备工序、降低生产成本并减少工艺调控要素。通过对硅溶胶凝胶实验的初步研究,探讨硅溶胶凝胶包覆VO_(2)(M)的工艺参数,并通过实验验证硅溶胶凝胶包覆VO_(2)(M)的可行性。研究结果表明,当pH为5~6、固含量为15%~20%(质量分数)时,硅溶胶的凝胶化能力最佳。此外,随着凝胶温度升高,凝胶时间缩短,焙烧后得到的SiO_(2)粉体结晶性和热稳定性增加。根据优化后的硅溶胶凝胶工艺参数成功制备了致密稳定的核壳结构VO_(2)(M)@SiO_(2)材料,其包覆程度达到93.3%,薄膜的光学透过率提升至65%,且其相变温度降低和热滞后回线宽度变窄。因此,硅溶胶凝胶法为制备高性能的核壳结构VO_(2)(M)@SiO_(2)材料提供了一种简化工艺和降低成本的方法,对于智能窗等应用具有重要潜力。 展开更多
关键词 硅溶胶凝胶法 包覆 核壳结构 VO_(2)(m)@SiO_(2)材料
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基于M估计强混合重尾序列结构变点的鲁棒检验
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作者 朱玲 金浩 乔宝明 《统计与决策》 CSSCI 北大核心 2024年第8期34-40,共7页
针对强混合重尾序列结构变点的检测问题,为避免因序列重尾性导致最小二乘估计产生偏差,文章提出了基于M估计的比值型检验统计量,用于检测重尾序列位置结构变点。在一般约束条件下证明了原假设下统计量的极限分布是布朗运动的泛函,并得... 针对强混合重尾序列结构变点的检测问题,为避免因序列重尾性导致最小二乘估计产生偏差,文章提出了基于M估计的比值型检验统计量,用于检测重尾序列位置结构变点。在一般约束条件下证明了原假设下统计量的极限分布是布朗运动的泛函,并得到备择假设下的一致性。针对因序列相依性导致的经验水平扭曲现象,采用Block Bootstrap抽样方法获得了更为准确的临界值,有效提高了检验功效。数值模拟结果显示,在Block Bootstrap抽样方法下基于M估计的比值型检验在强混合重尾序列结构变点检测中能较好地控制经验水平,经验势也较合理。最后,通过一组汇率数据验证了所提检验方法的可行性。 展开更多
关键词 结构变点 比值型检验 重尾 Block Bootstrap m估计
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Crystal Structure and Properties of Europium m-Chlorobenzoate Complex with 1,10-Phenanthroline 被引量:3
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作者 王瑞芬 王淑萍 张建军 《Journal of Rare Earths》 SCIE EI CAS CSCD 2004年第6期816-820,共5页
A europium m-chlorobenzoate complex with 1,10-phenanthroline [Eu(m-ClBA)_3(phen)]_2 single crystal, where m-ClBA=m-chlorobenzoate and phen=1,10- phenanthroline,was prepared and structurally characterized by X-ray diff... A europium m-chlorobenzoate complex with 1,10-phenanthroline [Eu(m-ClBA)_3(phen)]_2 single crystal, where m-ClBA=m-chlorobenzoate and phen=1,10- phenanthroline,was prepared and structurally characterized by X-ray diffraction. It crystallizes in triclinic, space group P1- with a=1.10138(8)nm, b=(1.18606(9) nm,) c=1.32516(10) nm, α=112.5390(10)°, β=92.1700(10)°, γ=101.6220(10)°,(C_(66))H_(40)N_4O_(12)Cl_6Eu_2, M_r=1597.64, V=1.5533(2) nm^3, Z=1, D_c=1.708 g·cm^(-3), μ(Mo Kα)=2.325 mm^(-1), (F(000))= 788, the final R=0.0424 and wR=0.0899 for 6856 independent reflections with R_(int)=(0.0776.)The crystal consists of binuclear molecules of the title compound. Each Eu^(3+) ion is nine-coordinated to one 1,10-phenanthroline molecule, one bidentate carboxylate group and four bridging carboxylate groups. The carboxylate groups are bonded to the europium ion in three modes: the chelating bidentate, the bridging bidentate and bridging-chelating thridentate. Excitation and luminescence data observed at room temperature show that the title complex (emits) very intensive red fluorescence under ultraviolet light. The results of thermal analysis indicate that the complex [Eu(m-ClBA)_3(phen)]_2 is quite stable to heat. 展开更多
关键词 EUROPIUm m-chlorobenzoic acid 1 10-PHENANTHROLINE crystal structure luminescence thermal decomposition rare earths
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Absence of BCS–BEC crossover in FeSe_(0.45)Te_(0.55) superconductor
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作者 贾俊杰 谷亚东 +21 位作者 殷超辉 束英杰 陈逸雯 史聚民 张杏 陈浩 苗泰民 任晓琳 梁波 朱文培 蔡能 张丰丰 张申金 杨峰 王志敏 彭钦军 许祖彦 毛寒青 刘国东 任治安 赵林 周兴江 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第7期79-85,共7页
In iron-based superconductor Fe(Se,Te), a flat band-like feature near the Fermi level was observed around the Brillouin zone center in the superconducting state. It is under debate whether this is the evidence on the ... In iron-based superconductor Fe(Se,Te), a flat band-like feature near the Fermi level was observed around the Brillouin zone center in the superconducting state. It is under debate whether this is the evidence on the presence of the BCS–BEC[Bardeen–Cooper–Schrieffer(BCS), Bose–Einstein condensation(BEC)] crossover in the superconductor. High-resolution laser-based angle-resolved photoemission measurements are carried out on high quality single crystals of FeSe_(0.45)Te_(0.55) superconductor to address the issue. By employing different polarization geometries, we have resolved and isolated the dyz band and the topological surface band, making it possible to study their superconducting behaviors separately. The dyz band alone does not form a flat band-like feature in the superconducting state and the measured dispersion can be well described by the BCS picture. We find that the flat band-like feature is formed from the combination of the dyz band and the topological surface state band in the superconducting state. These results reveal the origin of the flat band-like feature and rule out the presence of BCS-BEC crossover in Fe(Se,Te) superconductor. 展开更多
关键词 FeSe_(0.45)Te_(0.55) ARPES electronic structure superconducting gap bcS–BEC crossover
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Construction for M-arrays and application in structured light 被引量:1
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作者 贾小军 张之江 喻擎苍 《Journal of Shanghai University(English Edition)》 CAS 2011年第1期63-68,共6页
M-arrays are random arrays in which an appropriate sub-window appears only once in the whole array. Coded structured light based on M-arrays is one=shot technique to rapidly acquire 3D information of unknown surfaces ... M-arrays are random arrays in which an appropriate sub-window appears only once in the whole array. Coded structured light based on M-arrays is one=shot technique to rapidly acquire 3D information of unknown surfaces by projecting suitable patterns onto a measuring surface. This paper presents a method to construct large size M-arrays based on the piece growing algorithm in which an array is constructed by many pieces through splicing each other. Reconstructing 3D shapes by utilizing the designed pattern based on constructed M-arrays for two objects are given. 展开更多
关键词 m-arrays structured light piece growing 3D reconstruction
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Principal axes of M-DOF structures Part I:Static loading 被引量:1
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作者 Zack Liang George C.Lee 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2002年第2期293-302,共10页
This paper is the first in a two-part series that discusses the principal axes of M-DOF structures subjected to static and dynamic loads. The primary purpose of this series is to understand the magnitude of the dynami... This paper is the first in a two-part series that discusses the principal axes of M-DOF structures subjected to static and dynamic loads. The primary purpose of this series is to understand the magnitude of the dynamic response of structures to enable better design of structures and control modification devices/systems. Under idealized design conditions, the structural responses are obtained by using single direction input ground motions in the direction of the intended control devices/systems, and by assuming that the responses of the structure is decoupleable in three mutually perpendicular directions. This standard practice has been applied to both new and retrofitted structures using various seismic protective systems. Very limited information is available on the effects of neglecting the impact of directional couplings (cross effects - of which torsion is a component) of the dynamic response of structures. In order to quantify such effects, it is necessary to examine the principal axes of structures under both static and dynamic loading. This first paper deals with quantitative definitions of principal axes and “cross effects” of three-dimensional structures under static load by using linear algebra. It shows theoretically that, for three-dimensional structures, such principal axes rarely exist. Under static loading conditions, the cross effect is typically small and negligible from the viewpoint of engineering applications. However, it provides the theoretical base for subsequent quantification of the response couplings under dynamic loads, which is reported in part II of this series. 展开更多
关键词 principal axes of m-DOF structures structural response couplings cross effect theoretical base
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Crystal Structure and Luminescence Spectra of Novel Coordination Layer of {[Eu(m-BDC)(NO_3)(Phen)(H_2O)]_2·2CH_3CH_2OH}_n 被引量:1
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作者 王明召 夏江滨 +1 位作者 蔡冠梁 吕少哲 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第2期138-142,共5页
The crystal structure of a novel Eu^(3+) coordination polymer, {[Eu(m-BDC)(NO_3)(Phen)(H_2O)]_2·2CH_3CH_2OH}_n (m-BDC=1,3-benzenedicarboxylate, Phen=1, 10-phenanthroline), was obtained and its high-resolution lum... The crystal structure of a novel Eu^(3+) coordination polymer, {[Eu(m-BDC)(NO_3)(Phen)(H_2O)]_2·2CH_3CH_2OH}_n (m-BDC=1,3-benzenedicarboxylate, Phen=1, 10-phenanthroline), was obtained and its high-resolution luminescence spectra at 77K were measured. The μ_2-carboxylate of m-BDC constructs the binuclear building block in which each Eu^(3+) ion is coordinated by four oxygen atoms of m-BDC anions, one oxygen atom from water molecule, two oxygen atoms of nitrate and two nitrogen atoms of Phen, respectively. The μ_1-carboxylate of m-BDC conjugates the binuclear units one-dimensional chain or a ribbon, while the hydrogen bonds between ribbons assemble the structure two-dimensional layer with a thickness equaling to the width of the ribbon. The luminescence spectra reveal that the two Eu^(3+) ion sites in the binuclear building blocks have slight environmental difference. The C_1 local symmetry of Eu^(3+) ion is concluded from both crystal structure measurement and luminescence spectra. 展开更多
关键词 europium m-benzenedicarboxylate coordination layer crystal structure luminescence rare earths
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Surge Response of a Compliant Offshore Structure by Time Domain Simulation 被引量:2
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作者 王迎光 薛雷平 谭家华 《Journal of Shanghai Jiaotong university(Science)》 EI 2007年第6期838-844,共7页
A single-degree-of-freedom equation of motion was used for modeling a compliant offshore structure exposed to viscous hydrodynamic loads. The equation of motion contains nonlinearities in the forms of both Duffing sti... A single-degree-of-freedom equation of motion was used for modeling a compliant offshore structure exposed to viscous hydrodynamic loads. The equation of motion contains nonlinearities in the forms of both Duffing stiffness and Morison drag force with current. The water particle velocity and acceleration for calculating the Morison inertia and drag forces are modeled as Gaussian processes based on a Pierson-Moskowitz (P-M) elevation spectrum. The single-degree-of-freedom equation of motion containing different ocean current values are then numerically integrated via a fourth-order Runge-Kutta scheme. Time trajectories of the surge response displacements of the offshore structure and the response probability density curves are obtained. Furthermore, the ocean current influences on the response central moments up to the fourth order are studied. A literature review reveals that this is the first treatment of such a pair of nonlinearities in time domain. The simulation results are analyzed, and some conclusions valuable for engineering design are pointed out. 展开更多
关键词 compliant OFFSHORE structure SURGE RESPONSE morison drag FORCE P-m SPECTRUm mONTE Carlo simulation
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Seismic intensity investigation of the 2001 M=6.0 Yajiang-Kangding earthquake and discussion on its background of seismogenic structures
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作者 何玉林 张勤 黄伟 《Acta Seismologica Sinica(English Edition)》 CSCD 2002年第1期63-73,共11页
An M=6.0 earthquake occurred on February 23, 2001 in the western Sichuan Province, China. The macro seismic epicenter situated in the high mountain-narrow valley region between Yajiang and Kangding counties. According... An M=6.0 earthquake occurred on February 23, 2001 in the western Sichuan Province, China. The macro seismic epicenter situated in the high mountain-narrow valley region between Yajiang and Kangding counties. According to field investigation in the region, the intensity of epicentral area reached VIII and the areas with intensity VIII, VII and VI are 180 km2, 1 472 km2 and 3 998 km2, respectively. The isoseismals are generally in elliptic shape with major axis trending near N-S direction. The earthquake destroyed many buildings and produced some phenomena of ground failure and mountainous disasters in the area with intensity VIII. This event may be resulted from long-term activities of the Litang fault and Yunongxi fault, two main faults in the western Sichuan. The movements between the main faults made the crust stress adjusted and concentrated, and finally the earthquake on a secondary fault in the block released a quite large energy. 展开更多
关键词 seismic intensity isoseismal ground failure seismogenic structure Yajiang-Kangding m=6.0 earthquake
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The geometry structures and electronic properties of Li_mB_n(m+n=12) clusters
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作者 阮文 谢安东 +2 位作者 伍冬兰 罗文浪 余晓光 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第3期206-211,共6页
The geometric structures, electronic properties, total and binding energies, harmonic frequencies, the highest occupied molecular orbital to the lowest unoccupied molecular orbital energy gaps, and the vertical ioniza... The geometric structures, electronic properties, total and binding energies, harmonic frequencies, the highest occupied molecular orbital to the lowest unoccupied molecular orbital energy gaps, and the vertical ionization potential energies of small LimBn (m+ n = 12) clusters were investigated by the density functional theory B3LYP with a 6-31 I+G (2d, 2p) basis set. All the calculations were performed using the Gaussian09 program. For the study of the LimBn clusters, the global minimum of the B 12 cluster was chosen as the starting point and the boron atoms were gradually replaced by Li atoms. The results showed that as the number of Li atoms increased, the stability of the LimBn cluster decreased and the physical and chemical properties became more active. In addition, on average there was a large charge transfer from the Li atoms to the B atoms. 展开更多
关键词 LimBn m n = 12) clusters density functional theory geometry structures electronic properties
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Proposal for Offshore Wind Farm with Triangle-Coupled Movable Parallelogram Buoyancy Structure for the High Seas 被引量:1
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作者 Tatsuhiko Nagata 《Journal of Energy and Power Engineering》 2022年第3期126-145,共20页
We are responsible for providing energy and food resources for our next generation.After more than 20 years of research,the author has confirmed that the VAWT with flip-up mechanism can maintain rotation without the b... We are responsible for providing energy and food resources for our next generation.After more than 20 years of research,the author has confirmed that the VAWT with flip-up mechanism can maintain rotation without the brake,even in strong winds.Experiments have shown that the triangularly coupled movable parallelogram buoyancy structure makes it easy to maintain the verticality of the wind turbine tower even under large waves.Furthermore,as a result of studying the connection between the HAWT(horizontal axis wind turbine)and the movable parallelogram buoyancy structure of the triangular connection,the feasibility was confirmed.The only way for all people in the world to secure energy and food fairly is to look for the remaining areas such as the high seas.The author would like to propose the use of the high seas to combat global hunger,which is likely to be a global problem in the future. 展开更多
关键词 Energy and food resources for our grandchildren and following generations deeper than 200 m offshore triangle-coupled movable parallelogram buoyancy structure VAWT with flip-up mechanism HAWT high seas.
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Crystal Structure and Chemical Composition of Ludwigite from Vranovac Ore Deposit (Boranja Mountain,Serbia) 被引量:1
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作者 Pavle TANCIC Radovan DIMITRIJEVIC +2 位作者 Maja POZNANOVIC Aleksandar PACEVSKI Slobodanka SUDAR 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2012年第6期1524-1538,共15页
The crystal structure of ludwigite from Vranovac ore deposit (Boranja Mt., Serbia) was refined using the X-ray powder diffraction (XRPD) Rietveld method in the space group Pbam to a final RB=7.45% and RF=5.26%. It... The crystal structure of ludwigite from Vranovac ore deposit (Boranja Mt., Serbia) was refined using the X-ray powder diffraction (XRPD) Rietveld method in the space group Pbam to a final RB=7.45% and RF=5.26%. It has the unit cell dimensions of: a=9.2515(2) A; b=12.3109(2) A; c=3.03712 (7) A; and V=345.91(1) A3. The calculated distances and angles are mostly in good agreement with the Mg2+-Fe2+ substitutions across the M(1) and M(3) sites, as well as with the Fe3+-AI3+ replacement in the M(4) site. However, the mean observed M(2)-O distance is considerably shorter than prescribed, due to a slight increase of the Fe3+ content in the M(2) site. Such replacement was compensated by slight increase of the Fe2+ content in the M(4) site, resulting in the (Mg1.4sFe2+o.46Fe3+o.osMno.o2)2.o1 (Fe3+o.94Fe2+0.04Al0.02)1.00B1.00Os composition. The formation temperature was estimated to be about 500- 600C. The influences of the various chemical compositions to the crystallographic parameters, M-O distances, M(3) and M(4) sites shift, distortion parameters and estimated valences, were also studied and compared with other reference samples. 展开更多
关键词 LUDWIGITE crystal structure chemical composition m-O distances distortion parameters ions valences comparison formation temperature
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