应用近红外光谱技术快速鉴别玉米杂交种纯度的研究

采用近红外光谱分析技术结合定性偏最小二乘法对农大108玉米杂交种的纯度进行了鉴别研究,实验采用农大108杂交种子与母本178种子各100粒进行单粒光谱扫描(建模集与检验集比例为3:1),结果表明:透射孔直径为3 mm 时,所建模型平均鉴别率为99.82%,显著高于透射孔直径为4.5 mm 时所建模型的鉴别率90.96%;采用胚乳面一次光谱、胚面两次平均光谱、胚乳面两次平均光谱和四次平均光谱进行建模,其平均鉴别率筹异不显著,检验集平均鉴别率均达到99%左右,略高于胚面一次光谱;选择透射孔径3.0 mm,4 000～8 000 cm1 光谱范围,种子胚乳面单次光谱所建立的农大108玉米杂交种的种子纯度鉴定模型的建模集和检验集的鉴别率均达到100%.     

Investigation of 515 nm green-light emission for full color emission LaAlO3 phosphor with varied valence Eu

Photoluminescence and lifetime decay properties of varied valence Eu were employed to investigate the luminescence mechanism of green-light emission positioned at ∼515 nm for full color emission LaAlO₃ phosphor co-doped with Eu²⁺ and Eu³⁺. The enhanced ⁵D₂→⁷F₃ transition emission of Eu³⁺ was assigned for this green emission. Energy transfer between Eu²⁺ and ⁵D₂ level of Eu³⁺ was proposed, which results in the enhancement of ⁵D₂→⁷F₃ transition emission. In addition, energy transfer relations between host-Eu and charge transfer state (CTS)-Eu were also discussed associated with the PLE spectra and band schemes.     

Multilayer dielectric cylindrical mirrors based on omnidirectional reflection from a one-dimensional photonic crystal

A multilayer dielectric cylindrical mirror (MDCM) based on the one-dimensional omnidirectional reflection of a photonic crystal is presented. In this case, the refractive indices of the two materials are 1.6 (polystyrene) and 4.6 (tellurium), and the corresponding optimized thicknesses are 0.75a and 0.25a. A very high reflectance over a wide frequency range is observed. In this case, a is the lattice constant of the photonic crystal. In this band, the MDCM has good reflection and focal properties. Therefore, it is feasible to use the MDCM for integrated waveguide devices. As an example, an etched diffraction grating demultiplexer based on the MDCM is also proposed. Both the operational principle and design of the device are introduced. This provides a method for designing compact integrated waveguide devices.     

Synthesis and physical properties of antiperovskite-type compound In0.95CNi3

The compound In_0.95CNi₃ has been synthesized and the basic properties have been investigated. It has the typical antiperovskite structure (space group Pm3m, lattice parameter 3.7836 Å). The electronic specific coefficient γ and Debye temperature Θ_D are found to be 14.1 mJ/mol K² and 372 K, respectively. It behaves as a ferromagnetic metal below the Curie temperature (577 K). The emergence of ferromagnetism is suggested to originate from the deviation of the Ni/In atomic ratio from the ideal stoichiometry. The possible mechanisms have been discussed in detail in terms of this deviation.     

Chern–Simons,Wess–Zumino and other cocycles from Kashiwara–Vergne and associators

Descent equations play an important role in the theory of characteristic classes and find applications in theoretical physics, e.g., in the Chern–Simons field theory and in the theory of anomalies. The second Chern class (the first Pontrjagin class) is defined as \(p= \langle F, F\rangle \) where F is the curvature 2-form and \(\langle \cdot , \cdot \rangle \) is an invariant scalar product on the corresponding Lie algebra \(\mathfrak g\). The descent for p gives rise to an element \(\omega =\omega _3+\omega _2+\omega _1+\omega _0\) of mixed degree. The 3-form part \(\omega _3\) is the Chern–Simons form. The 2-form part \(\omega _2\) is known as the Wess–Zumino action in physics. The 1-form component \(\omega _1\) is related to the canonical central extension of the loop group LG. In this paper, we give a new interpretation of the low degree components \(\omega _1\) and \(\omega _0\). Our main tool is the universal differential calculus on free Lie algebras due to Kontsevich. We establish a correspondence between solutions of the first Kashiwara–Vergne equation in Lie theory and universal solutions of the descent equation for the second Chern class p. In more detail, we define a 1-cocycle C which maps automorphisms of the free Lie algebra to one forms. A solution of the Kashiwara–Vergne equation F is mapped to \(\omega _1=C(F)\). Furthermore, the component \(\omega _0\) is related to the associator \(\Phi \) corresponding to F. It is surprising that while F and \(\Phi \) satisfy the highly nonlinear twist and pentagon equations, the elements \(\omega _1\) and \(\omega _0\) solve the linear descent equation.     

Experimental determination of counterflow ignition temperatures and laminar flame speeds of C2–C3 hydrocarbons at atmospheric and elevated pressures

Experimental data were acquired for: (1) the ignition temperatures of nitrogen–diluted ethylene and propylene by counterflowing heated air for various strain rates and system pressures up to 7 atm; (2) the laminar flame speeds of mixtures of air with acetylene, ethylene, ethane, propylene, and propane, deduced from an outwardly propagating spherical flame in a constant-pressure chamber, for extensive ranges of lean-to-rich equivalence ratio and system pressure up to 5 atm. These data, respectively, relevant for low- to intermediate-temperature ignition chemistry and high-temperature flame chemistry, were subsequently compared with calculated results using a literature C₁–C₃ mechanism and an ethylene mechanism. Noticeable differences were observed in the comparison for both mechanisms, and sensitivity analyses were conducted to identify the reactions of importance.     

Synthesis and magnetic properties of CoFe2O4 ferrite nanoparticles

CoFe₂O₄ ferrite nanoparticles were prepared by a modified chemical coprecipitation route. Structural and magnetic properties were systematically investigated. X-ray diffraction results showed that the sample was in single phase with the space group . The results of field-emission scanning electronic microscopy showed that the grains appeared spherical with diameters ranging from 20 to 30 nm. The composition determined by energy-dispersive spectroscopy was stoichiometry of CoFe₂O₄. The Curie temperature in the process of increasing temperature was slightly higher than that in the process of decreasing temperature. This can be understood by the fact that heating changed Co²⁺ ion redistribution in tetrahedral and in octahedral sites. The coercivity of the synthesized CoFe₂O₄ samples was lower than the theoretical values, which could be explained by the mono-domain structure and a transformation from ferrimagnetic to superparamagnetic state.     

A hierarchy of Hamiltonian lattice equations associated with the relativistic Toda type system

By considering a discrete iso-spectral problem, a hierarchy of bi-Hamiltonian relativistic Toda type lattice equations are revisited. After introducing a semi-direct sum Lie algebras of four by four matrices, integrable coupling system associated with the relativistic Toda type lattice are derived. It is shown that the resulting lattice soliton hierarchy possesses Hamiltonian structures and infinitely many common commuting symmetries as well infinitely many conserved functions. The Liouville integrability of the resulting system is then demonstrated.     

A result on the Gelfand-Kirillov dimension of representations of classical groups

Let be the reductive dual pair . We show that if is a representation of (respectively ) obtained from duality correspondence with some representation of (respectively ), then its Gelfand-Kirillov dimension is less than or equal to
(respectively ).