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The Dihedral Angle and Intersection Processes of a Conjugate Strike-Slip Fault System in the Tarim Basin, NW China 被引量:19
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作者 WU Guanghui YUAN Yajuan +4 位作者 HUANG Shaoying Thomas Matthew Vandyk XIAO Yang CAI Quan LUO Bingxu 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2018年第1期74-88,共15页
Recent studies, focused on dihedral angles and intersection processes, have increased understandings of conjugate fault mechanisms. We present new 3-D seismic data and microstructural core analysis in a case study of ... Recent studies, focused on dihedral angles and intersection processes, have increased understandings of conjugate fault mechanisms. We present new 3-D seismic data and microstructural core analysis in a case study of a large conjugate strike-slip fault system from the intracratonic Tarim Basin, NW China. Within our study area, "X" type NE and NW trending faults occur within Cambrian- Ordovician carbonates. The dihedral angles of these conjugate faults have narrow ranges, 19~ to 62~ in the Cambrian and 26~ to 51~ in the Ordovician, and their modes are 42~ and 44~ respectively. These data are significantly different from the ~60~ predicted by the Coulomb fracture criterion. It is concluded that: (1) The dihedral angles of the conjugate faults were not controlled by confining pressure, which was low and associated with shallow burial; (2) As dihedral angles were not controlled by pressure they can be used to determine the shortening direction during faulting; (3) Sequential slip may have played an important role in forming conjugate fault intersections; (4) The conjugate fault system of the Tarim basin initiated as rhombic joints; these subsequently developed into sequentially active "X" type conjugate faults; followed by preferential development of the NW-trending faults; then reactivation of the NE trending faults. This intact rhombic conjugate fault system presents new insights into mechanisms of dihedral angle development, with particular relevance to intracratonic basins. 展开更多
关键词 Conjugate fault STRIKE-SLIP dihedral angle fault intersection faulting process Carbonate
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T型尾翼颤振特性分析方法 被引量:13
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作者 吕斌 吴志刚 杨超 《工程力学》 EI CSCD 北大核心 2008年第2期230-234,共5页
由于T型尾翼特殊的结构和气动布局形式,其颤振特性的分析比较复杂,飞行状态和一些常规分析可以忽略的参数如上反角都会对颤振速度有很大影响。针对这些特殊问题,分析了T型尾翼的颤振特性受平尾上反角、平尾上的定常气动力和固有振动形... 由于T型尾翼特殊的结构和气动布局形式,其颤振特性的分析比较复杂,飞行状态和一些常规分析可以忽略的参数如上反角都会对颤振速度有很大影响。针对这些特殊问题,分析了T型尾翼的颤振特性受平尾上反角、平尾上的定常气动力和固有振动形式等因素的影响。重点研究了T型尾翼颤振计算中特殊的附加非定常气动力,建立了T型尾翼非定常气动力和颤振分析方法。在低速风洞中开展了T型尾翼缩比模型的颤振试验,验证了分析方法。结果表明T型尾翼特殊的气动效应主要影响垂尾的弯扭耦合颤振形式,颤振速度随平尾攻角增加而降低,在设计中采用一定的平尾下反角设计能够提高T型尾翼的颤振速度。通过对试验结果的理论分析,阐述了这种效应产生的机理,并对实际设计提出建议。 展开更多
关键词 气动弹性 T型尾翼 颤振 非定常气动力 上反角 定常升力
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One-regular Normal Cayley Graphs on Dihedral Groups of Valency 4 or 6 with Cyclic Vertex Stabilizer 被引量:5
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作者 JinHoKWAK JuMokOH 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2006年第5期1305-1320,共16页
A graph G is one-regular if its automorphism group Aut(G) acts transitively and semiregularly on the arc set. A Cayley graph Cay(Г, S) is normal if Г is a normal subgroup of the full automorphism group of Cay(... A graph G is one-regular if its automorphism group Aut(G) acts transitively and semiregularly on the arc set. A Cayley graph Cay(Г, S) is normal if Г is a normal subgroup of the full automorphism group of Cay(Г, S). Xu, M. Y., Xu, J. (Southeast Asian Bulletin of Math., 25, 355-363 (2001)) classified one-regular Cayley graphs of valency at most 4 on finite abelian groups. Marusic, D., Pisanski, T. (Croat. Chemica Acta, 73, 969-981 (2000)) classified cubic one-regular Cayley graphs on a dihedral group, and all of such graphs turn out to be normal. In this paper, we classify the 4-valent one-regular normal Cayley graphs G on a dihedral group whose vertex stabilizers in Aut(G) are cyclic. A classification of the same kind of graphs of valency 6 is also discussed. 展开更多
关键词 one-regular graph Cayley graph dihedral group half-transitive graph
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The Role of Elytra in Beetle Flight: Ⅰ.Generation of Quasi-Static Aerodynamic Forces 被引量:5
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作者 Patar Ebenezer Sitorus Hoon Cheol Park +2 位作者 Doyoung Byun Nam Seo Goo Cheol Heui Han 《Journal of Bionic Engineering》 SCIE EI CSCD 2010年第4期354-363,共10页
We conducted a comprehensive study to investigate the aerodynamic characteristics and force generation of the elytra of abeetle,Allomyrina dichotoma.Our analysis included wind tunnel experiments and three-dimensional ... We conducted a comprehensive study to investigate the aerodynamic characteristics and force generation of the elytra of abeetle,Allomyrina dichotoma.Our analysis included wind tunnel experiments and three-dimensional computational fluiddynamics simulations using ANSYS-CFX software.Our first approach was a quasi-static study that considered the effect ofinduced flapping flow due to the flapping motion of the fore-wings (elytra) at a frequency of around 30 Hz to 40 Hz.The dihedralangle was varied to represent flapping motion during the upstroke and downstroke.We found that an elytron producespositive lift at 0° geometric angle of attack,negative lift during the upstroke,and always produces drag during both the upstrokeand downstroke.We also found that the lift coefficient of an elytron does not drop even at a very high geometric angle of attack.For a beetle with a body weight of 5 g,based on the quasi-static method,the fore-wings (elytra) can produce lift of less than 1%of its body weight. 展开更多
关键词 ELYTRA angle of attack dihedral angle CFD wind tunnel test
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Dihedral influence on lateral–directional dynamic stability on large aspect ratio tailless flying wing aircraft 被引量:4
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作者 Song Lei Yang Hua +2 位作者 Zhang Yang Zhang Haoyu Huang Jun 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2014年第5期1149-1155,共7页
The influence of dihedral layout on lateral–directional dynamic stability of the tailless flying wing aircraft is discussed in this paper. A tailless flying wing aircraft with a large aspect ratio is selected as the ... The influence of dihedral layout on lateral–directional dynamic stability of the tailless flying wing aircraft is discussed in this paper. A tailless flying wing aircraft with a large aspect ratio is selected as the object of study, and the dihedral angle along the spanwise sections is divided into three segments. The influence of dihedral layouts is studied. Based on the stability derivatives calculated by the vortex lattice method code, the linearized small-disturbance equations of the lateral modes are used to determine the mode dynamic characteristics. By comparing 7056 configurations with different dihedral angle layouts, two groups of stability optimized dihedral layout concepts are created. Flight quality close to Level 2 requirements is achieved in these optimized concepts without any electric stability augmentation system. 展开更多
关键词 dihedral angle Flying wing Optimization Stability Tailless
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Augmentation quotients for complex representation rings of dihedral groups 被引量:3
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作者 Shan CHANG Hong CHEN Guoping TANG 《Frontiers of Mathematics in China》 SCIE CSCD 2012年第1期1-18,共18页
Denote by Dm the dihedral group of order 2m. Let R(Dm) be its complex representation ring, and let △(Dm) be its augmentation ideal. In this paper, we determine the isomorphism class of the n-th augmentation quoti... Denote by Dm the dihedral group of order 2m. Let R(Dm) be its complex representation ring, and let △(Dm) be its augmentation ideal. In this paper, we determine the isomorphism class of the n-th augmentation quotient △^n(Dm)/△^n+1(Dm) for each positive integer n. 展开更多
关键词 dihedral group REPRESENTATION augmentation quotient
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A fast and efficient mesh segmentation method based on improved region growing 被引量:3
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作者 YANG Fei ZHOU Fan +2 位作者 WANG Ruo-mei LIU Li LUO Xiao-nan 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2014年第4期468-480,共13页
Mesh segmentation is one of the important issues in digital geometry processing. Region growing method has been proven to be a efficient method for 3D mesh segmentation. However, in mesh segmentation, feature line ext... Mesh segmentation is one of the important issues in digital geometry processing. Region growing method has been proven to be a efficient method for 3D mesh segmentation. However, in mesh segmentation, feature line extraction algorithm is computationally costly, and the over-segmentation problem still exists during region merging processing. In order to tackle these problems, a fast and efficient mesh segmentation method based on improved region growing is proposed in this paper. Firstly, the dihedral angle of each non-boundary edge is defined and computed simply, then the sharp edges are detected and feature lines are extracted. After region growing process is finished, an improved region merging method will be performed in two steps by considering some geometric criteria. The experiment results show the feature line extraction algorithm can obtain the same geometric information fast with less computational costs and the improved region merging method can solve over-segmentation well. 展开更多
关键词 mesh segmentation feature line region growing dihedral angle.
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高负荷压气机叶栅的叶身/端壁融合研究 被引量:5
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作者 彭学敏 季路成 +1 位作者 伊卫林 刘艳明 《工程热物理学报》 EI CAS CSCD 北大核心 2014年第2期242-246,共5页
叶身/端壁融合(BBEW)是有潜力支撑风扇/压气机负荷最大化的原创技术.本文以大折转亚音叶栅和超音速叶栅两类趋向负荷极限叶栅为案例,在二面角原理指导下,采用数值方法对比研究了第一类(增大二面角型)和第二类(变曲率过渡曲面)BBEW改型... 叶身/端壁融合(BBEW)是有潜力支撑风扇/压气机负荷最大化的原创技术.本文以大折转亚音叶栅和超音速叶栅两类趋向负荷极限叶栅为案例,在二面角原理指导下,采用数值方法对比研究了第一类(增大二面角型)和第二类(变曲率过渡曲面)BBEW改型。结果表明,两类BBEW改型均能有效削弱或消除高负荷压气机叶栅角区分离,且具有良好的工况适应性。其中,第一类BBEW改型虽外形上类似叶片倾斜,但作用机理却截然不同,附面层交汇作用超过叶片力作用. 展开更多
关键词 叶身 端壁融合 角区分离 二面角 高负荷压气机 数值模拟
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Micro-Raman studies on the conformational behaviors of monosodium glutamate in dehydration process 被引量:2
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作者 Jing Jing Shou Guang Zeng Hao Zhang Yun Hong Zhang 《Chinese Chemical Letters》 SCIE CAS CSCD 2011年第7期855-858,共4页
The conformational behaviors of monosodium glutamate (MSG) in a dehydration process were studied by Micro-Raman spectroscopy in combination with Hartree-Fock calculations using 6-3 1+G^* method. The dehydration pr... The conformational behaviors of monosodium glutamate (MSG) in a dehydration process were studied by Micro-Raman spectroscopy in combination with Hartree-Fock calculations using 6-3 1+G^* method. The dehydration process of the MSG droplet was performed by decreasing the ambient relative humidity (RH). The intensity ratio of the 935 cm^-1 band to 884 cm^-1 band (I935/ 1884) kept decreasing when RH decreased. By optimizing the geometries with different fixed dihedral angles, the downtrend of (I935/I884) is found to be due to the reduction of MSG molecular volume. 展开更多
关键词 RAMAN MSG CALCULATION DEHYDRATION INTENSITY dihedral angle
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Enumeration of Cubic Cayley Graphs on Dihedral Groups 被引量:2
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作者 Xue Yi HUANG Qiong Xiang HUANG Lu LU 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2017年第7期996-1010,共15页
Let p be an odd prime, and D2p = (a,b I aP = b2 = l,bab= a 1) the dihedral group of order 2p. In this paper, we completely classify the cubic Cayley graphs on D2p up to isomorphism by means of spectral method. By th... Let p be an odd prime, and D2p = (a,b I aP = b2 = l,bab= a 1) the dihedral group of order 2p. In this paper, we completely classify the cubic Cayley graphs on D2p up to isomorphism by means of spectral method. By the way, we show that two cubic Cayley graphs on D2p are isomorphic if and only if they are cospectral. Moreover, we obtain the number of isomorphic classes of cubic Cayley graphs on D2 by using Gauss' celebrated law of quadratic reciprocity. 展开更多
关键词 Cayley graph dihedral group cospectral isomorphic classes quadratic reciprocity
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Nowhere-zero 3-flows in Cayley graphs on generalized dihedral group and generalized quaternion group 被引量:2
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作者 Liangchen LI Xiangwen LI 《Frontiers of Mathematics in China》 SCIE CSCD 2015年第2期293-302,共10页
Tutte conjectured that every 4-edge-connected graph admits a nowhere-zero 3-flow. In this paper, we show that this conjecture is true for Cayley graph on generalized dihedral groups and generalized quaternion groups, ... Tutte conjectured that every 4-edge-connected graph admits a nowhere-zero 3-flow. In this paper, we show that this conjecture is true for Cayley graph on generalized dihedral groups and generalized quaternion groups, which generalizes the result of F. Yang and X. Li [Inform. Process. Lett., 2011, 111: 416-419]. We also generalizes an early result of M. Nanasiova and M. Skoviera [J. Algebraic Combin., 2009, 30: 103-110]. 展开更多
关键词 Nowhere-zero 3-flow Cayley graph generalized dihedral group generalized quaternion group
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基于高阶边界散射变换的二面角快速成像算法
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作者 杨俊慧 诸葛晓栋 《电波科学学报》 CSCD 北大核心 2023年第6期950-959,共10页
基于二面角的单站圆周扫描模型,本文分析了不同张角二面角的奇次反射回波分布规律.通过建立正向散射模型并求解在各观测角度下对散射场贡献最大的出射点,证明了在二面角内的各种散射中,镜面反射起主导作用.基于此,本文只考虑镜面反射对... 基于二面角的单站圆周扫描模型,本文分析了不同张角二面角的奇次反射回波分布规律.通过建立正向散射模型并求解在各观测角度下对散射场贡献最大的出射点,证明了在二面角内的各种散射中,镜面反射起主导作用.基于此,本文只考虑镜面反射对散射场的贡献,建立了出射边驻定相位点与回波波前之间的一一对应关系,提出了一种高阶边界散射变换(high-order boundary scattering transform,HBST)算法,有效消除了由多次反射带来的成像伪影.相较传统的后向投影算法,本文提出的HBST算法在计算量和成像效率上都有显著的提升,仿真和实验结果验证了算法的有效性. 展开更多
关键词 二面角 边界散射变换(BST) 多次反射 驻定相位点 快速成像
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一种含Tröger碱单元的AIE分子的独特力致荧光增强行为
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作者 倪珏宸 臧启光 +2 位作者 张浩可 孙景志 唐本忠 《Science China Materials》 SCIE EI CAS CSCD 2023年第5期1959-1967,共9页
本文报道了一种性能独特的聚集诱导发光分子DTPE-TB,它由位于中间的一个Tröger碱和两端的两个四苯基乙烯(TPE)基团构成.当DTPE-TB分子固体受到机械力作用时,Tröger碱的A-型结构通过改变二面角发生形变承载外力,使分子内运动... 本文报道了一种性能独特的聚集诱导发光分子DTPE-TB,它由位于中间的一个Tröger碱和两端的两个四苯基乙烯(TPE)基团构成.当DTPE-TB分子固体受到机械力作用时,Tröger碱的A-型结构通过改变二面角发生形变承载外力,使分子内运动受限加重,固体荧光增强.而TPE基团受力很小,其排列方式基本不变,所以发光波长仅有微小移动.我们将这种特殊的力致发光变色效应命名为力致荧光增强. 展开更多
关键词 aggregation-induced emission mechano-induced emission enhancement dihedral angle Λ-shaped configuration Tröger’s base
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Isomorphisms of Cubic Cayley Graphs on Dihedral Groups and Sparse Circulant Matrices
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作者 Istvan KOVACS 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2023年第4期618-632,共15页
We show that,up to isomorphism,there is a unique non-CI connected cubic Cayley graph on the dihedral group of order 2n for each even number n≥4.This answers in the negative the question of Li whether all connected cu... We show that,up to isomorphism,there is a unique non-CI connected cubic Cayley graph on the dihedral group of order 2n for each even number n≥4.This answers in the negative the question of Li whether all connected cubic Cayley graphs are CI-graphs(Discrete Math.,256,301-334(2002)).As an application,a formula is derived for the number of isomorphism classes of connected cubic Cayley graphs on dihedral groups,which generalises the earlier formula of Huang et al.dealing with the particular case when n is a prime(Acta Math.Sin.,Engl.Ser.,33,996-1011(2017)).As another application,a short proof is also given for a result on sparse circulant matrices obtained by Wiedemann and Zieve(arXiv preprint,(2007)). 展开更多
关键词 Cayley graph graph isomorphism dihedral group circulant matrix
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The Power of Group Generators and Relations: An Examination of the Concept and Its Applications
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作者 Tiancheng Zhou 《Journal of Applied Mathematics and Physics》 2018年第11期2425-2444,共20页
This paper investigates the approach of presenting groups by generators and relations from an original angle. It starts by interpreting this familiar concept with the novel notion of “formal words” created by juxtap... This paper investigates the approach of presenting groups by generators and relations from an original angle. It starts by interpreting this familiar concept with the novel notion of “formal words” created by juxtaposing letters in a set. Taking that as basis, several fundamental results related to free groups, such as Dyck’s Theorem, are proven. Then, the paper highlights three creative applications of the concept in classifying finite groups of a fixed order, representing all dihedral groups geometrically, and analyzing knots topologically. All three applications are of considerable significance in their respective topic areas and serve to illustrate the advantages and certain limitations of the approach flexibly and comprehensively. 展开更多
关键词 Generators and RELATIONS Free GROUP Dyck’s Theorem dihedral GROUP Presentation Classification of Finite GROUPS (Application) Realizing dihedral GROUPS Geometrically (Application) KNOT GROUP (Application)
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Theoretical Studies on Structures, Stabilities, NMR Spectra and Designing Methods of Dihedral Fullerenes of C3 Series 被引量:1
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作者 LI Ping 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2014年第6期1032-1043,共12页
Using bowl shaped carbon intermediates to construct dihedral fullerenes is an advisable method. Assu- ming that cap shaped C21 extends the size through building pentagons and hexagons at the U and V clefts of the brim... Using bowl shaped carbon intermediates to construct dihedral fullerenes is an advisable method. Assu- ming that cap shaped C21 extends the size through building pentagons and hexagons at the U and V clefts of the brims, a series of homologous carbon intermediates was generated, in which most of the members have been unknown up to now. The joins between these homologous intermediates gave the C3 dihedral series under the restriction of C3 sym- metrical axis. The investigations point out that the stabilities of these fullerenes not only relate to the shapes of cages and the co-planarities of polygons, but also associate with the equalizations of bond lengths and the pentagonal dis- tributions. The stabilities reveal that the pentagonal distribution in cages is not negligible to the Jr delocalization, be- sides the co-planarities of hexagons and pentagons. Analyzing the possible Stone-Wales(SW) rearrangements in those fullerenes with dehydrogenated pyracyclene units(DPUs) can help us to find out the highly stable isomers. Based on the geometrical optimizations, the calculations provided the theoretical chemical shifts of unknown fullerenes and the data reconfirmed the existence of members C78 and C84. The symmetry adaptation analyses for the frontier orbitals support the formative mechanism of consecutive pentagonal and hexagonal fusions, but the simulated routes are more complicated than the pentagon road(PR) mechanism, which include not only C2 but also C3 additive reactions. 展开更多
关键词 dihedral fullerene Curvature Distortion Pentagon and hexagon Chemical shift Stone-Wales(SW) ar-rangement Density functional theory
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On Non-normal Arc-Transitive 4-Valent Dihedrants 被引量:1
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作者 István KOVCS Botjan KUZMAN Aleksander MALNI 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2010年第8期1485-1498,共14页
Let X be a connected non-normal 4-valent arc-transitive Cayley graph on a dihedral group Dn such that X is bipartite, with the two bipartition sets being the two orbits of the cyclic subgroup within Dn. It is shown th... Let X be a connected non-normal 4-valent arc-transitive Cayley graph on a dihedral group Dn such that X is bipartite, with the two bipartition sets being the two orbits of the cyclic subgroup within Dn. It is shown that X is isomorphic either to the lexicographic product Cn[2K1] with n 〉 4 even, or to one of the five sporadic graphs on 10, 14, 26, 28 and 30 vertices, respectively. 展开更多
关键词 Cayley graph arc transitivity dihedral group
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Crystal Structure of 3-(4-Methoxyphenyl)-2-(4-methylbenzoyl)-6,7-dihydro-5H-furo[3,2-g]chromene 被引量:1
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作者 李晗悦 韩宇 +4 位作者 金辄 王世辉 李新增 刘思宇 胡春 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2016年第4期545-549,共5页
The crystal structure of 3-(4-methoxyphenyl)-2-(4-methylbenzoyl)-6,7-dihydro-5H-furo[3,2-g]chromene was obtained by X-ray single-crystal diffraction. The molecule is in the triclinic crystal system, space group P1... The crystal structure of 3-(4-methoxyphenyl)-2-(4-methylbenzoyl)-6,7-dihydro-5H-furo[3,2-g]chromene was obtained by X-ray single-crystal diffraction. The molecule is in the triclinic crystal system, space group P1 with a = 11.0745(4), b = 13.0953(7), c = 15.8773(8) ?, α = 92.811(4), β = 104.815(4), γ = 111.797(4)o, Z = 4, the final R = 0.0567 and w R = 0.1540. X-ray crystal structure data revealed that one asymmetric structure unit of the title compound contained two molecules. The existence of methyl group changed the dihedral angle between furan ring and the phenyl ring at the C2 position of the furo[3,2-g]chromene scaffold as well as the conformation, and had a further influence on the bioactivity of the furo[3,2-g]chromene derivatives. 展开更多
关键词 furo[3 2-g]chromene crystal structure dihedral angle bioactivity
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RCS Evaluation of Dihedral corner Renector by Complex Ray Method 被引量:1
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作者 DuHuiping RuanYingzheng 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 1996年第1期31-36,共6页
With the techniques provided by the complex my method,like co,nplex ray expansion, complex mytracing,complex my paraxial approximation, etc.,the back scatter of dihedral corner reflectors is evaluated.Numerical result... With the techniques provided by the complex my method,like co,nplex ray expansion, complex mytracing,complex my paraxial approximation, etc.,the back scatter of dihedral corner reflectors is evaluated.Numerical results show that this method gives good and useful RCS prediction of the targets. 展开更多
关键词 s:radar cross section(RCS) dihedral corner reflector radar absorbing materials.complex ray method(CRM)
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Spherical f-Tilings by Scalene Triangles and Isosceles Trapezoids, Ⅱ 被引量:1
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作者 Catarina P. AVELINO Altino F.SANTOS 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2012年第5期1013-1032,共20页
The study of the dihedral f-tilings of the sphere S2 whose prototiles are a scalene triangle and an isosceles trapezoid was initiated in a previous work. In this paper we continue this classification presenting the st... The study of the dihedral f-tilings of the sphere S2 whose prototiles are a scalene triangle and an isosceles trapezoid was initiated in a previous work. In this paper we continue this classification presenting the study of all dihedral spherical f-tilings by scalene triangles and isosceles trapezoids in some cases of adjacency. 展开更多
关键词 dihedral f-tilings combinatorial properties spherical trigonometry
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