带弦圈的最小2宽直径

设k为正整数,G是简单k连通图.图G的k宽直径,dk(G),是指最小的整数ι使得对任意两不同顶点x,y∈V(G),都存在k条长至多为ι的内部不交的连接x和y的路.用C(n,t)表示在圈Gn上增加t条边所得的图.定义h(n,t):min{d2(C(n,t))}.本文给出了h(n,2)=[n/2].而且,给出了当t较大时h(n,t)的界.     

A possible interpretation of the Higgs mass by the cosmological attractive relaxion

Recently, a novel idea [1] has been proposed to relax the electroweak hierarchy problem through the cosmological inflation and the axion periotic potential. Here, we further assume that only the attractive inflation is needed to explain the light mass of the Higgs boson, where we do not need a specified periodic potential of the axion field. Attractive inflation during the early universe drives the Higgs boson mass from the large value in the early universe to the small value at present, where the Higgs mass is an evolving parameter of the Universe. Thus, the small Higgs mass can technically originate from the cosmological evolution rather than dynamical symmetry or anthropics. Further, we study the possible collider signals or constraints at a future lepton collier and the possible constraints from the muon anomalous magnetic moment. A concrete attractive relaxion model is also discussed, which is consistent with the data of Planck 2015.     

Reservoir Pore Structure Classification Technology of Carbonate Rock Based on NMR T 2 Spectrum Decomposition

The carbonate reservoir has a number of properties such as multi-type pore space, strong heterogeneity, and complex pore structure, which make the classification of reservoir pore structure extremely difficult. According to nuclear magnetic resonance (NMR) T ₂ spectrum characteristics of carbonate rock, an automatic pore structure classification and discrimination method based on the T ₂ spectrum decomposition is proposed. The objective function is constructed based on the multi-variate Gaussian distribution properties of the NMR T ₂ spectrum. The particle swarm optimization algorithm was used to solve the objective function and get the initial values and then the generalized reduced gradient algorithm was proposed for solving the objective function, which ensured the stability and convergence of the solution. Based on the featured parameters of the Gaussian function such as normalized weights, spectrum peaks and standard deviations, the combinatory spectrum parameters (by multiplying peak value and normalized weight for every peak) are constructed. According to the principle of fuzzy clustering, the carbonate rock pore structure is classified automatically and the discrimination function of each pore structure type is obtained using Fisher discrimination analysis. The classification results were analyzed with the corresponding casting thin section and scanning electron microscopy. The study shows that the type of the pore structure based on the NMR T ₂ spectrum decomposition is strongly consistent with other methods, which provides a good basis for the quantitative characterization of the carbonate rock reservoir pore space and lays a foundation of the carbonate rock reservoir classification based on NMR logging.     

Luminescence and time-resolved spectroscopy properties of (Gd1−xEux)(BO2)3 multicrystals

(Gd_1?xEu_x)(BO₂)₃ (0≤x≤1) phosphors are synthesized by traditional high temperature solid state reaction. The photoluminescence (PL) properties of Gd(BO₂)₃ and Gd(BO₂)₃ activated with Eu³⁺ are investigated. The PL spectra exhibit the typical characteristic emission and excitation of Gd³⁺ and Eu³⁺ ions, and support the energy transfer taking place from Gd³⁺ to Eu³⁺ ions. The relationship between Eu³⁺ doping concentration and emission intensity is also studied. Even if all of the Gd³⁺ ions are substituted by Eu³⁺ ions, the concentration quenching between Eu³⁺ happens. However, the quenching is not complete. The luminescence decay curves are measured, and the lifetimes become short with the Eu³⁺ content increasing. The decreasing Gd³⁺ lifetimes also indicates that there exists efficient energy transfer between Gd³⁺ and Eu³⁺ ions.     

Thermodynamic and conformational investigation of the influence of CdTe QDs size on the toxic interaction with BSA

Water-soluble fluorescent colloidal quantum dots (QDs) have been widely used in some biological and biomedical fields, so the interaction of QDs with biomolecules recently attracts increasing attention. In this study, the fluorescence (FL) quenching method, circular dichroism (CD) technique, attenuated total reflection-Fourier transform infrared (ATR-FTIR) and UV-vis absorption spectra were used to investigate systematically the influence of CdTe QDs size on the toxic interaction with bovine serum albumin (BSA). Three size CdTe QDs with maximum emission of 543 nm (green-emitting QDs, GQDs), 579 nm (yellow-emitting QDs, YQDs) and 647 nm (red-emitting QDs, RQDs) were tested. The Stern-Volmer quenching constant (K_sv) at different temperatures, corresponding thermodynamic parameters (ΔH, ΔG and ΔS), and information of the structural features of BSA were gained. The FL results indicated that QDs can effectively quench the FL of BSA in a size-dependent manner, electrostatic interactions play a major role in the binding reaction, and the nature of quenching is static, resulting in forming QDs-BSA complexes. The CD and ATR-FTIR spectra showed that the secondary structure of BSA was changed by QDs, indicating the toxic on protein.     

Direct Synthesis of High-Quality Water-Soluble CdTe:Zn(2+) Quantum Dots

The synthesis of water-soluble and low-cytotoxicity quantum dots (QDs) in aqueous solution has received much attention recently. A one-step and convenient method has been developed for synthesis of water-soluble glutathione (GSH)-capped and Zn(2+)-doped CdTe QDs via a refluxing route. Because of the addition of Zn ions and the epitaxial growth of a CdS layer, the prepared QDs exhibit superior properties, including strong fluorescence, minimal cytotoxicity, and enhanced biocompatibility. The optical properties of QDs are characterized by UV-vis and fluorescence (FL) spectra. The structure of QDs was verified by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectrometry (XPS), energy dispersive spectroscopy (EDS), atomic absorption spectrometry (AAS), and Fourier transform infrared spectroscopy (FTIR). Furthermore, the low cytotoxicity of the prepared QDs was proved by the microcalorimetric technique and inductively coupled plasma-atomic emission spectrometry (ICP-AES).     

水下圆柱壳体固有频率的近似计算分析

水下发射导弹在出、入水以及水下运行过程中,由于流体、水动力以及运动速度的影响,产生附加质量和轴向荷载作用,影响结构振动频率.本文针对水下高速运动结构,给出了流体影响、轴向荷载分别作用以及二者同时作用下,结构频率的固有频率计算方法;并从理论分析、数值模拟和实验研究三个方面对水下的结构的固有频率进行了分析和研究.近似计算表明计算结果具有较好的一致性,而且由于流体和轴向荷载的影响,结构的固有频率有明显下降的趋势,而且对低阶频率影响较大.     

求解稳恒磁场的谐函数展开法

推导出稳恒磁场矢势的谐函数展开式,当稳恒电流的分布适宜于用直角坐标系表示时,可应用该展开式求解磁场,给出了应用该展开式求解稳恒磁场的例子。     

铝酸盐水泥矿物结构与性能的量子化学计算研究

用量子化学的电荷自洽离散变分Xα(SCC-DV-Xα)计算方法研究了CaO-Al₂O₃系统五种水泥矿物的结构、性能与化学键之间的关系及固溶的杂质离子Na⁺对矿物性能的影响。计算结果表明:Ca-O共价键强度的次序是C₃A < C₁₂A₇ < CA < CA₂ < CA₆,且各矿物的Ca-O键强度都小于它们的Al-O键强度,与相应的水泥矿物水化活性的实验结果一致。Na⁺固溶于C₃A结构后使其Al-O键增强,水化活化能变大,态密度减小,被认为是Na⁺降低C₃A水化活性的主要原因。     

CaWO4核/卤化银壳光敏微晶的制备及性能研究

用于感光材料的卤化银微晶合成技术近二十年来取得了很大进展,合成出了诸如T-颗粒、核壳乳剂和外延复合颗粒等,使感光材料的性能日趋优异。但由于感光化学反应(如化学增感、光谱增感、潜影形成及显影过程等)基本上都发生在微晶的表面,而微晶核内部的卤化银却未发生作用,而随定影过程被溶解成废液,这样便造成贵金属银的浪费。