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91.
A method is suggested to determine experimentally whether the state of a spin system is oriented or non-oriented by measuring
the angular distribution,I and the circular polarization asymmetry,A
c of the photons emitted by the system. These also provide enough data to determine the density matrix completely. 相似文献
92.
Yao Hailou 《数学季刊》1998,(3)
§1. IntroductionLetAbeanartinalgebra,modAbethecategoryoffinitelygeneratedrightA-modules,ΓAbeitsAuslander-Reitenquiver,thenthereisanonzeromapbetweenanytwonon-isomorphicmodulesinmodAifandonlyifthereisapathbetweenthetwoverticescorrespondingtothesetwomod… 相似文献
93.
T. H. Marshall 《Journal of Graph Theory》2006,52(3):200-210
We prove that every oriented planar graph admits a homomorphism to the Paley tournament P271 and hence that every oriented planar graph has an antisymmetric flow number and a strong oriented chromatic number of at most 271. © 2006 Wiley Periodicals, Inc. J Graph Theory 52: 200–210, 2006 相似文献
94.
Jeffrey D. Miller 《Journal of statistical physics》1991,63(1-2):89-113
We calculate the direction-direction correlations between the tangent vectors of an oriented self-avoiding walk (SAW). LetJ
(x) andJ
v
(0) be components of unit-length tangent vectors of an oriented SAW, at the spatial pointsx and 0, respectively. Then for distances |x| much less than the average distance between the endpoints of the walk, the correlation function ofJ
(x) withJ
v
(0) has, ind dimensions, the form
. The dimensionless amplitudek(d) is universal, and can be calculated exactly in two dimensions by using Coulomb gas techniques, where it is found to bek(2)=12/25
2. In three dimensions, the -expansion to second order in together with the exact value ofk(2)in two dimensions allows the estimatek(3)=0.0178±0.0005. In dimensionsd4, the universal amplitudek(d) of the direction-direction correlation functions of an oriented SAW is the same as the universal amplitude of the direction-direction correlation functions of an oriented random walk, and is given byk(d)=
2(d/2)/(d–2)
d
. 相似文献
95.
Richard Durrett Roberto H. Schonmann Nelson I. Tanaka 《Journal of statistical physics》1989,55(5-6):965-979
Oriented percolation has two correlation lengths, one in the space and one in the time direction. In this paper we define these quantities for the two-dimensional model in terms of the exponential decay of suitably chosen quantities, and study the relationship between the various definitions. The definitions are used in a companion paper to prove inequalities between critical exponents. 相似文献
96.
97.
尝试在"高分子材料合成创新实验"课程中将理论课的知识点巧妙地融入到实验教学中,有目的地设置实验环节,通过对实验现象的分析,帮助学生巩固理论课知识点。为了充分利用实验的等待时间,在有目的地组织学生对实验进行预习的基础上,还尝试"激励学生参与"实验课的教学,鼓励学生以实验小组的形式讲解与实验相关联的理论知识,进一步巩固相关知识点,并扩充知识面。2年的实验教学反馈表明,这些尝试既有效巩固了理论课堂的知识点,做到了活学活用,又激发了学生的学习兴趣,提高了分析问题的能力。 相似文献
98.
99.
100.
Xintu Lin Yincai Wu Lingna Cui Xi Chen Shuhong Fan Yuejun Liu Xiaochao Liu Wei Zheng 《先进技术聚合物》2022,33(1):137-145
Biaxially oriented polyamide-6 (BOPA) film has been widely used in many packaging applications. However, the BOPA film with excellent toughness is still required when utilizing in the field of soft-packaged lithium - ion batteries, pharmaceutical blister packaging, or frozen food packaging especially for vacuum packaging of irregular-shaped food products. The purpose of this study was to improve the toughness of BOPA films by toughening with poly(ether block amide) (PEBA) (BOPA/PEBA films) based on the simultaneous biaxial stretching technology. The crystal structure, morphology, optical properties, barrier, and mechanical properties of BOPA/PEBA films were investigated. The results showed that the incorporation of PEBA into BOPA films slightly decreased the melting temperature and crystallinity of PA6, and the BOPA/PEBA films exhibited only α-form crystals and no preferential orientation in the machine direction (MD) and transition direction (TD). The morphological observation showed that higher addition of PEBA led to the formation of microvoids due to the poor compatibility between PA6 and PEBA. As a result, the transmittance and oxygen barrier properties of the BOPA/PEBA films decreased. In addition, mechanical analysis suggested that the addition of PEBA could effectively improve the toughness of BOPA film. 相似文献