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Let R be a Noetherian unique factorization domain such that 2 and 3 are units,and let A=R[α]be a quartic extension over R by adding a rootαof an irreducible quartic polynomial p(z)=z4+az2+bz+c over R.We will compute explicitly the integral closure of A in its fraction field,which is based on a proper factorization of the coefficients and the algebraic invariants of p(z).In fact,we get the factorization by resolving the singularities of a plane curve defined by z4+a(x)z2+b(x)z+c(x)=0.The integral closure is expressed as a syzygy module and the syzygy equations are given explicitly.We compute also the ramifications of the integral closure over R. 相似文献
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Computation is devoted to evaluating structural safety of a heat exchanger inside a reactor whose geometry can be simplified as outer and inner pipes as well as a chamber. This paper has numerically studied deflagration of hydrogen air mixture and pipe dynamic responses. The Navier-Stokes equations coupled with multi-species mass equation are solved by TVD scheme to get flow-field solution based on MPI and multi-block methods. Combustion is described by a 11-species and 23-step reaction model. The source te... 相似文献
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Clear effects criterion is one of the important rules for selecting optimal fractional factorial designs, and it has become
an active research issue in recent years. Tang et al. derived upper and lower bounds on the maximum number of clear two-factor
interactions (2fi’s) in 2
n−(n−k) fractional factorial designs of resolutions III and IV by constructing a 2
n−(n−k) design for given k, which are only restricted for the symmetrical case. This paper proposes and studies the clear effects problem for the asymmetrical
case. It improves the construction method of Tang et al. for 2
n−(n−k) designs with resolution III and derives the upper and lower bounds on the maximum number of clear two-factor interaction
components (2fic’s) in 4
m
2
n
designs with resolutions III and IV. The lower bounds are achieved by constructing specific designs. Comparisons show that
the number of clear 2fic’s in the resulting design attains its maximum number in many cases, which reveals that the construction
methods are satisfactory when they are used to construct 4
m
2
n
designs under the clear effects criterion.
This work was supported by the National Natural Science Foundation of China (Grant Nos. 10571093, 10671099 and 10771123),
the Research Foundation for Doctor Programme (Grant No. 20050055038) and the Natural Science Foundation of Shandong Province
of China (Grant No. Q2007A05). Zhang’s research was also supported by the Visiting Scholar Program at Chern Institute of Mathematics. 相似文献
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Thermal entanglement in a mixed-spin Heisenberg XXZ model under a nonuniform external magnetic field
The thermal entanglement in (1/2,1) mixed-spin Heisenberg XXZ model is investigated under an external nonuniform magnetic
field. In the uniform magnetic field system, the critical magnetic field B
c and critical temperature T
c are increased by increasing the anisotropic parameter k. The degree of magnetic field b plays an important role in improving the critical temperature and enlarging the region of entanglement in the nonuniform
magnetic field system. 相似文献
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HU RenTao Lü LiangFei RUAN BanFeng WANG Peng ZHANG MingLiang ZHOU HongPing LI ShengLi WU JieYing & TIAN YuPeng Department of Chemistry Chemical Engineering Key Laboratory of Functional Inorganic Materials Chemistry of Anhui Province Anhui University Hefei China 《中国科学B辑(英文版)》2009,52(8):1210-1215
Two carbazole-based polymerization initiators possessing blue fluorescence emission have been synthesized via Wittig reaction
in the solid phase at room temperature. Two-photon excited fluorescence (TPEF) spectra for them were investigated under 800
nm fs laser pulse and two-photon absorption cross sections were determined by the Z-scan technique. Then two-photon initiating
polymerization (TPIP) microfabrication experiments were successfully carried out. Three-dimensional lattice and artificial
defects were gained, indicating that they were viable candidates for the two-photon polymerization initiator in practical
application of microfabrication.
Supported by the National Natural Science Foundation of China (Grant Nos. 50532030, 20771001 & 50703001), and Team for Scientific
Innovation of Anhui Province (Grant No. 2006KJ007TD) 相似文献
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YANG Fan LIU YuWen OU LiHui WANG Xin & CHEN ShengLi Hubei Electrochemical Power Sources Key Laboratory 《中国科学:化学》2010,(2)
A density functional theory (DFT)-calculation scheme for constructing the modified embedded atom method (MEAM) potentials for face-centered cubic (fcc) metals is presented. The input quantities are carefully selected and a more reliable DFT approach for surface energy determination is introduced in the parameterization scheme, enabling MEAM to precisely predict the surface and nanoscale properties of metallic materials. Molecular dynamics simulations on Pt and Au crystals show that the parameterization empl... 相似文献
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SHAO ZhengZheng ZHANG XueAo WANG XiaoFeng & CHANG ShengLi Center of Materials Science College of Science National University of Defense Technology Changsha China 《中国科学:物理学 力学 天文学(英文版)》2010,(1)
The electrical characteristics of Pt-ZnO Schottky nano-contact have been studied. Well aligned ZnO nanorod arrays were synthesized by two-step wet-chemical method. A Pt-coated conducting probe of atomic force microscope was placed on the head face of the ZnO nanorod, thereby forming a Pt-ZnO nano-contact. The I-V characteristic curve shows that the Pt-ZnO nano-contact exhibits rectifying effect, like a Schottky diode with an ideality factor of 3.2 and a reverse-bias breakdown voltage more than -10 V. The st... 相似文献
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在水溶液中合成了5-氨基间苯二甲酸钠(1)和5-羟基间苯二甲酸钠(2)固态样品,元素分析和TG-DTG确定其组成符合C8H5O4NNa2·H2O(1)和C8H4O5Na2·H2O(2).用精密自动绝热热量计测定了它们在78~400K温区的低温热容,将实验值用最小二乘法拟合,得到热容随温度变化的多项式方程,用此方程进行数值积分,得到该温区内每隔5K的舒平热容值和各种热力学函数值.用RD496-2000型微热量计测定了样品在298.15K时的标准摩尔溶解焓分别为ΔsolHmθ(1,s)=-44.552±0.164kJmol-1和θΔsolHm(2,s)=-36.055±0.154kJmol-1,计算了其水合阴离子标准摩尔生成焓分别为θΔfHm(C8H5O4N2-,aq)=-684.56±1.67kJmol-1和ΔfHmθ(C8H4O52-,aq)=-1263.43±2.13kJmol-1.用RBC-II型精密转动弹热量计测定了样品的恒容燃烧热分别为ΔcU(1,s)=-13382.14±5.28Jg-1和ΔcU(2,s)=-10339.15±4.15Jg-1,计算了它们的标准摩尔燃烧焓和标准摩尔生成焓分别为ΔcHmθ(1,s)=-3252.90±1.28kJmol-1和θΔcHm(2,s)=-2522.64±1.01kJmol-1,ΔfHmθ(1,s)=-1406.46±1.66kJmol-1,θΔfHm(2,s)=-1993.79±1.46kJmol-1. 相似文献