关于Sz\''{a}sz算子的强逆不等式

本文应用新的$K$-泛函$K_{\lambda}^{\alpha}(f,t^2)=\inf_{g\in C_{\lambda}^2}\{\|f-g\|_0+t^2\|g\|_2\}, ~~0\leq \lambda\leq 1, 0<\alpha<2,$得到了Sz\'{a}sz算子关于$K$-泛函的强逆不等式,其中$\|\cdot\|_{0}, \|\cdot\|_2, C_\lambda^2 $定义在文中给出. 作为其应用, 我们推广了以前的结果.     

On Generalized Nonlinear Burgers＇ Equation

In this work, we study the similarity analysis of the generalized nonlinear Burgers＇ equation having diffusivity and viscosity as a general functions of the particle velocity. We perform the symmetry analysis and exhibit exact solutions for various forms of the diffusivity and viscosity.     

乙酰化聚苯乙烯型载体红外定量分析

通过Friedel-Crafts酰基化反应得到乙酰化聚苯乙烯型载体,采用红外光谱对反应前后物质表征,由产物特征峰吸光值换算对聚苯乙烯微球取代度进行定量,与传统增重率得出结论误差最小为0.12%,具有很好定量效果且简易可行.     

FAAS法测定千年不烂心中硒的含量

探讨了湖北恩施产千年不烂心中硒含量的测定方法,采用APDC-MIBK体系络合萃取,分离富集后,以火焰原子吸收光度法进行测定.本法克服了硒原子化效率低以及稳定剂铜对测定的干扰.方法的相对标准偏差为4.90%,回收率为96.O%-98.5%.     

图$P_m\times P_n, P_m\times C_n$ 和C_m\times C_n$}的邻点可区别全色数的注记

设 $G$ 是一个简单图. 设$f$是从$V(G) \cup E(G)$到 $\{1, 2,\ldots, k\}$的一个映射.对任意的 $v\in V(G)$, 设$C_f(v)=\{f(v)\}\cup \{f (vw)|w\in V(G),vw\in E(G)\}$ . 如果 $f$ 是一个 $k$-正常全染色, 且对 $u, v\in V(G),uv\in E(G)$, 有 $C_f(u)\neq C_f(v)$, 那么称 $f$ 为$k$-邻点可区别全染色 (简记为$k$-$AVDTC$). 设     

离散型最小和最大次序统计量相关性研究

本文研究离散型随机变量之间的相关性度量, 讨论了最小次序统计量和最大次序统计量的渐近独立性, 给出了计算最小次序统计量和最大次序统计量的Kendall和Spearman秩相关系数的公式.     

4-溴邻苯二胺的合成

采用两条路线合成４溴邻苯二胺,并对路线（Ⅱ）中水解一步作了探讨这两条路线是：１．用漆原镍催化氢化 ４溴２硝基苯胺;２．邻苯二胺溴化后,碱水解中间体 Ｎ, Ｎ（４溴１,２苯基）双乙酰胺     

Total Synthesis of (±)-Nimbonone and (±)-12-Ethyl-13-methoxy- 8,11,13-podocarpatriene

Most diterpenoids exhibit significant bioactivities, such as antidermatophytic, antibact- erial, and antioxidant. Although a large number of aromatic tricyclic diterpenoids have been isolated, there are a few of them having ethyl substituent. The synthesis of this type diterpenoids has been seldom reported. In order to further study the relationship between the structure and bioactivities of the diterpenoid, we extended the diterpene synthesis1,2,3. It is desirable to report herein the syn…     

The Electronic Structures and Chemical Bonding of Some Dinuclear and Trinuclear Low－valence Molybdenum Complexes Containing Thiolate Bridges

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MULTIPLE MELTING BEHAVIOR OF β-CRYSTALLINE PHASE POLYPROPYLENE

Differential scanning calorimetry and X-ray diffraction experiments on β-nucleated polypropylene were made on the samples crystallized at different temperatures and processed by injection molding. The crystal perfection was shown to vary with crystallization temperature. The observed multiple peaks could be related to a ill-phase with defective inclination of the chains, a recrystallized or original β_2-phase of more perfect inclination, and the α-phase. Injection molded samples could be analyzed from the established DSC interpretation.