有限域上二次型序列与几何序列的互相关性

§1Introduction Letpbeaprimenumber,q=pm,andFqdenotethefinitefieldwithqelements.Fo anyn≥1,Trmnm(·)isthetracefunctionfromFqntoFq.LetαbeaprimitiveelementofFq and{α1,α2,...,αn}beabasisofFqnoverFq.Definition1.ForanonlinearfunctionffromFqtoFp,thesequenceS={Si}qn-1i=1withit termdefinedby Si=f(Trmnm(αi))(1iscalledageometricsequence.SuchageometricsequenceShasperioddividingqn-1.Geometricsequences includingm-sequence[1],GMWsequence[2,3],cascadedGMWsequence[4,5]andman others[6],mayhavelar…     

Copper‐mediated simple and direct aerobic oxidative esterification of arylacetonitriles with alcohols/phenols

A simple and direct aerobic oxidative esterification reaction of arylacetonitriles with alcohols/phenols is achieved in the presence of a copper salt and molecular oxygen, which produces a broad range of aryl carboxylic acid esters in good to high yields. Copper salt plays multiple roles in the transformation, which allows the oxygenation of C? H bond, cleavage of inert C? C bond, and formation of C? O bond in one pot without the assistance of any of the acids, bases, ligands, and so on. The reaction provides a simple, direct, and efficient protocol towards functionalized esters, especially aryl benzoates, from readily available starting materials.     

花岗岩残积土浅层地基承载力评价方法探讨

花岗岩残积土是一种特殊性土体, 是混粒土的一种特殊类型, 从而导致浅层地基承载力也具有特殊性。作者首先分析了现行实验评价方法的利弊关系, 以大量的野外实验和室内实验资料为依据, 确定了其它测试方法评价该类土体浅层地基承载力的可行性, 并提出了利用标准贯入试验击数确定浅层地基承载力的修改方案。并探讨了土体含水量和浅层地基承载力和这些影响因素之间的相互关系。     

金川矿区深部高应力矿床开采关键技术研究与发展

金川矿区是我国唯一一座大型有色矿产资源生产基地。该矿体埋藏深、地应力高和围岩破碎所固有的不利条件,使得矿床在开采过程中面临极大困难。随着开采的延深,开采面积扩大,采场地压显现日趋剧烈,揭示和研究深埋、大面积采场的地压显现规律以及控制技术,是该类难采矿床安全、高效开采的关键。金川矿区自建矿30多年来,开展了大量的地压规律与控制技术的研究,积累了丰富的工程经验,解决了生产中的难题,使得矿山一期工程得以顺利实施。然而,随着二期工程的进展,尤其多中段开采水平矿柱日趋变薄的开采条件下,采场地压活动极为剧烈,巷道变形难以控制,并潜在着采场突变失稳的风险。本文在总结国内外难采矿床采场地压规律和控制技术研究的基础上,深入论述了金川1#矿体开采存在的问题、潜在的风险以及需要解决的关键技术难题。并明确了数值分析、现场监测与工程经验集于一体的动态反馈系统工程方法,是解决复杂采矿工程的必由之路。     

近紫外光激发的新型蓝色荧光粉YVxP1-xO4:Ta5+的合成与发光性能

采用高温固相法成功合成了Y(V,P)O4:Ta荧光粉,并利用XRD,激发光谱和发射光谱对所合成粉体的物相结构及发光性能进行了表征。实验结果表明:粉体的结构属于锆英石结构;粉体在310 nm波长的激发下,发射光谱的主峰位于450 nm,属于Ta5+的3p63d10→3p53d104d1跃迁,当n(V)/n(P)为0.3/0.7和Ta5+的摩尔掺杂浓度为0.01时,粉体的发光性能最佳;用不同浓度NH4NO3做助熔剂制备YV0.3P0.7O4:Ta50.+01荧光粉,发现NH4NO3的摩尔浓度为5%时,粉体的发光强度最强。     

Facile regio- and stereoselective hydrometalation of alkynes with a combination of carboxylic acids and group 10 transition metal complexes: selective hydrogenation of alkynes with formic acid

A facile, highly stereo- and regioselective hydrometalation of alkynes generating alkenylmetal complex is disclosed for the first time from a reaction of alkyne, carboxylic acid, and a zerovalent group 10 transition metal complex M(PEt(3))(4) (M = Ni, Pd, Pt). A mechanistic study showed that the hydrometalation does not proceed via the reaction of alkyne with a hydridometal generated by the protonation of a carboxylic acid with Pt(PEt(3))(4), but proceeds via a reaction of an alkyne coordinate metal complex with the acid. This finding clarifies the long proposed reaction mechanism that operates via the generation of an alkenylpalladium intermediate and subsequent transformation of this complex in a variety of reactions catalyzed by a combination of Br?nsted acid and Pd(0) complex. This finding also leads to the disclosure of an unprecedented reduction of alkynes with formic acid that can selectively produce cis-, trans-alkenes and alkanes by slightly tuning the conditions.     

Study on the temperature-induced sol–gel transition of cellulose/silk fibroin blends in 1-butyl-3-methylimidazolium chloride via rheological behavior

Temperature-induced sol–gel transition of cellulose/silk fibroin/1-butyl-3-methylimidazolium chloride ([BMIM]Cl) was studied from the viscosity and dynamic modulus of the mixtures. The shear thinning behavior of the mixture solution was very obvious with a decrease in temperature. The curves of storage modulus G′ and loss modulus G″ were parallel when the temperature was below 20 °C, indicating that a gel structure exists in the system. The sol–gel transition process was described according to Winter and Chambon’s theory. The gel structure of the mixture system was loosened with the increase of silk fibroin concentration.     

Rheological behavior of cellulose/silk fibroin blend solutions with ionic liquid as solvent

The rheological behavior of cellulose and silk fibroin blend in 1-butyl-3-methylimidazolium chloride was studied. The data from the rheological results was analyzed to understand the microstructure of the blend solutions. The viscosity and dynamic modulus of the blend solution decreased with increasing ratio of silk fibroin. While comparing the experimental results with the calculated data from the log-additivity rule, it is revealed that zero-shear viscosity, dynamic modulus show positive–negative deviations and a typical continuous–discrete type of morphology could be imaged. At lower shear rate, the change of phase morphology took place at the ratio of about 0.5 volume fraction of cellulose. However, the blend solution showed positive deviations for all cellulose/silk fibroin blend ratios at high shear rate, which indicates that the dispersion of cellulose and silk fibroin was improved under shear stress. The properties of cellulose/silk fibroin blends observed by Fourier transform infrared spectroscopy and scanning electron microcopy agreed with the result from rheology.