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Search Results: 1 - 10 of 36180 matches for " Yi Qian "
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Yangtzedonta and the early evolution of shelled molluscs
Qian Yi
Chinese Science Bulletin , 2001, DOI: 10.1007/BF02901142
Abstract: The holotype ofYangtzedonta Yu, 1985 and its type species,Y. primitiva Yu, 1985, is an incomplete specimen ofXianfengella prima He et Yang, 1982. Therefore, based on the principle of priority, the namesYangtzedonta and Y.primitiva Yu (1985) should be abandoned. The fact that ven-tral valve ofXianfengella is bilaterally symmetrical indicates that they are not the left valve of a bivalved mollusc, as originally proposed by Yu. At present, the oldest certain bi-valve isXianfengoconcha elliptica Zhang, which occurs in the Early Cambrian Qiongzhusi Stage in China. The oldest known rostroconch isHeraultipegma yunnanensis He et Yang, which first occurs in the third small shelly fossil assemblage zone of the Early Cambrian Meishucunian Stage. The oldest known monoplacophoran,Maikhanella pristinis (Jiang), first occurs in the first small shelly fossil assemblage zone (Me-ishucunian Stage). Evidence derived from analyses of shell morphology, mode of growth, histology, and stratigraphic occurrence suggests that bivalves evolved from a branch of rostroconchs, and that rostroconchs in turn evolved from a branch of monoplacophorans. The hypothesis that these three groups originated simultaneously and independently at the beginning of the Cambrian and subsequently evolved in parallel, probably is incorrect.
HS3 of the mouse β-LCR
Yi Tang,Ruolan Qian
Chinese Science Bulletin , 1997, DOI: 10.1007/BF02882954
Universal Ideal Behavior and Macroscopic Work Relation of Linear Irreversible Stochastic Thermodynamics
Yi-An Ma,Hong Qian
Physics , 2015, DOI: 10.1088/1367-2630/17/6/065013
Abstract: We revisit the Ornstein-Uhlenbeck (OU) process as the fundamental mathematical description of linear irreversible phenomena, with fluctuations, near an equilibrium. By identifying the underlying circulating dynamics in a stationary process as the natural generalization of classical conservative mechanics, a bridge between a family of OU processes with equilibrium fluctuations and thermodynamics is established through the celebrated Helmholtz theorem. The Helmholtz theorem provides an emergent macroscopic "equation of state" of the entire system, which exhibits a universal ideal thermodynamic behavior. Fluctuating macroscopic quantities are studied from the stochastic thermodynamic point of view and a non-equilibrium work relation is obtained in the macroscopic picture, which may facilitate experimental study and application of the equalities due to Jarzynski, Crooks, and Hatano and Sasa.
A Thermodynamic Theory of Ecology: Helmholtz Theorem for Lotka-Volterra Equation, Extended Conservation Law, and Stochastic Predator-Prey Dynamics
Yi-An Ma,Hong Qian
Mathematics , 2014, DOI: 10.1098/rspa.2015.0456
Abstract: We carry out mathematical analyses, {\em \`{a} la} Helmholtz's and Boltzmann's 1884 studies of monocyclic Newtonian dynamics, for the Lotka-Volterra (LV) equation exhibiting predator-prey oscillations. In doing so a novel "thermodynamic theory" of ecology is introduced. An important feature, absent in the classical mechanics, of ecological systems is a natural stochastic population dynamic formulation of which the deterministic equation (e.g., the LV equation studied) is the infinite population limit. Invariant density for the stochastic dynamics plays a central role in the deterministic LV dynamics. We show how the conservation law along a single trajectory extends to incorporate both variations in a model parameter $\alpha$ and in initial conditions: Helmholtz's theorem establishes a broadly valid conservation law in a class of ecological dynamics. We analyze the relationships among mean ecological activeness $\theta$, quantities characterizing dynamic ranges of populations $\mathcal{A}$ and $\alpha$, and the ecological force $F_{\alpha}$. The analyses identify an entire orbit as a stationary ecology, and establish the notion of "equation of ecological states". Studies of the stochastic dynamics with finite populations show the LV equation as the robust, fast cyclic underlying behavior. The mathematical narrative provides a novel way of capturing long-term dynamical behaviors with an emergent {\em conservative ecology}.
Tan Zheng-De,Hai Qian-Qian,Yi Bing
Acta Crystallographica Section E , 2010, DOI: 10.1107/s1600536810011979
Abstract: In the title complex, [Mn(C9H4N2O4)(H2O)2]n, the MnII atom is in a distorted octahedral coordination completed by one N atom from one 1H-benzimidazole-5,6-dicarboxylate ligand, two O atoms from two different 1H-benzimidazole-5,6-dicarboxylate ligands, and three O atoms from three water molecules. Two bridging water molecules and two bridging carboxylate groups from a 1H-benzimidazole-5,6-dicarboxylate ligand connect two MnII ions into a dimeric structure. In the crystal, extensive intermolecular O—H...O, N—H...O and C—H...O hydrogen bonding forms a three-dimensional network.
Chemical Composition and Energy Density in Coreius heterodon
WANG Qian-qian,LUO Yi-ping
Journal of Chongqing Normal University , 2010,
Abstract: 31 specimens of Coreius heterodon with body length(L) and body weight(W) rangingrespectively 9.2-32.0 cm and 11.3-504.0 g were collected from Mudong, Yangtze River in September,2007. The fish were divided into 4 groups according to the body length. Chemical compositions were measured and energy density was estimated. The results showed that the contents of ash(ASH), protein(PRO), liid(FAT) and water (WAT), represented by percentages of them in fresh body weight of fish, ranged 2.35%-5.20%,13.79-19.69%, 1.24%-19.32% and 61.63-80.69% respectively. The energy density(E) ranged 4.02-11.39 kj·g-1.The relationship between FAT or E and W could be described as :*and *. The relationship between FAT or E and WAT could be described as:FAT=80.03-1.01WAT (R2=0.926,P<0.01)and E=37.6-0.43 WAT (R2=0.963,P<0.01).The results suggest that the content of lipid and energy density of Coreius heterodon can be estimated bybody weight or the water content.The high lipid content in the larger fish is supposed to be correlated with its breeding activity.(* Indicates a formula, please see the full text)
The influence of spin-phonon coupling on antiferromagnetic spin fluctuations in FeSe under pressure: the First-principles calculations with van der Waals corrections
Qian-Qian Ye,Kai Liu,Zhong-Yi Lu
Physics , 2013, DOI: 10.1103/PhysRevB.88.205130
Abstract: The electronic structures, lattice dynamics, and magnetic properties of crystal {\beta}-FeSe under hydrostatic pressure have been studied by using the first-principles electronic structure calculations with van der Waals (vdW) corrections. With applied pressures, the energy bands around the Fermi energy level consisting mainly of Fe-3d orbitals show obvious energy shifts and occupation variations, and meanwhile the frequencies of all optical phonon modes increase. Among these phonon modes, the A1g mode, which relates to the Se height from the Fe-Fe plane, shows a clear frequency jump in the range between 5 and 6 GPa. This is also the pressure range within which the highest superconducting transition temperature Tc of FeSe is reached in experiments. In comparison with the other phonon modes, the zero-point vibration of the A1g mode induces the strongest fluctuation of local magnetic moment on Fe under a pressure from 0 to 9 GPa, and the induced fluctuation reaches the maximum around 5 GPa. These results suggest that the effect of phonon via spin-phonon coupling need to be considered when exploring the superconducting mechanism in iron-based superconductors.
Facile Synthesis and Thermal Stability of Nanocrystalline Molybdenum Carbide  [PDF]
Youjian Chen, Hong Zhang, Jinfeng Zhang, Jianhua Ma, Hongnan Ye, Gaojin Qian, Yi Ye, Shuang Zhong
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.29178
Abstract: Nanocrystalline molybdenum carbide (Mo2C) was prepared via one simple route by the reaction of metallic magnesium powders with molybdenum trioxide and potassium acetate in an autoclave at the condition of 600℃ and 4 h. X-ray powder diffraction (XRD) pattern indicated that the product was hexagonal α-Mo2C, and the cell constant was a = 3.0091 Å, c = 4.7368 Å. Scanning electron microscopy (SEM) image showed that the sample consisted of particles with an average size of about 100 nm in diameter. The product was also studied by the thermogravimetric analysis (TGA). It had good thermal stability and oxidation resistance below 450℃ in air.
An Advanced Electron Spin Resonance (ESR) Spin-Trapping and LC/(ESR)/MS Technique for the Study of Lipid Peroxidation
Yi Xu,Yan Gu,Steven Y. Qian
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms131114648
Abstract: There are two types of nutritionally important polyunsaturated fatty acids (PUFAs), namely ω-6s and ω-3s. PUFAs and their metabolites generated from lipid peroxidation via cyclooxygenase (COX) and lipoxygenase (LOX) are believed to be involved in a variety of physiological and pathological processes in the human body. Both COX- and LOX-catalyzed PUFA peroxidation are complex events that generate a series of radicals, which may then bind proteins, target DNA/RNA, and lead to a number of biological changes. However, due to the lack of an appropriate method, it was not possible until recently to identify the short-lived PUFA-derived radicals in COX-/LOX-catalyzed peroxidation. Failure to characterize free radicals during peroxidation has greatly restricted our knowledge about COX/LOX biology in human health. Here we review the development and refinement of combined ESR spin trapping and LC/ESR/MS to characterize PUFA-derived radicals formed from in vitro (cell-free) peroxidation. We also present the most recent approach for studying peroxidation in cells which allows us to directly assess the potential bioactivity of PUFA-derived free radicals. This advanced technique has resulted in a major breakthrough in radical structural characterization, as well as assessment of free radical-associated cell growth response, thereby greatly improving our knowledge of PUFAs, COX-/LOX-catalyzed lipid peroxidation, and their related biological consequences.
Amplifying stationary quantum discord and entanglement between a superconducting qubit and a data bus by time-dependent electromagnetic field
Yi Qian,YeQi Zhang,JingBo Xu
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-012-5112-4
Abstract: We study the dynamics of quantum discord and entanglement between a superconducting qubit and a data bus, which is driven by a controllable time-dependent electromagnetic field, in the presence of phase decoherence and find that the quantum discord and entanglement remain at a stationary non-zero value for long time evolution. It is shown that the amount of stationary quantum discord and entanglement can be enhanced by applying the time-dependent electromagnetic field.
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