L-Fuzzy理想的新刻画

借助于水平截集给出 L -fuzzy子环 ,L -fuzzy理想和 L -fuzzy素理想的若干新刻画     

智能高铁铁路枢纽场景5G-R信道与传播特性分析

为构建现代综合交通运输体系,支撑我国高速铁路向智能化方向发展,基于第五代移动通信技术(5G)的铁路5G专用移动通信(5G-R)系统将成为铁路智能联接的首选。2.1 GHz频段有望承载5G-R系统,支持铁路产业不断涌现的新业务。高速铁路枢纽场景是列车行车指挥和客货调度的中枢,具有业务量大、业务类型复杂等特点,对铁路通信系统提出了更高的要求。本文以厦门北站铁路枢纽为研究场景,基于电子地图建立三维场景模型,采用射线跟踪方法,仿真并分析场景的信道与传播特性,并提出了通信系统设计的相关建议。本文的研究结果将有助于为铁路枢纽场景5G-R系统设计与优化提供参考,提高铁路枢纽场景无线覆盖质量。     

溶剂萃取过程动力学研究--Ⅳ.单液滴法研究HEH(EHP)萃取Co2(Ⅱ)的速率与机理

采用单液滴法考察了水相酸度、钴(Ⅱ)在水相和有机相的浓度、萃取剂浓度以及温度和介质等因素对萃取速率的影响。结果表明,萃取反应机理是两步界面连续反应。文中对介质的影响也作了讨论。     

Preparation and Characterization of New Type Ionic Liquids

A new type of ionic liquids containing cation of diacetone acrylamide [or N-(1,1-bismethyl-3-oxo-butyl)acrylamide]and anions such as CH3COO^-(Ac),CF3COO^-(TF),BF4^-(BF),PF6^-(PF),HSO4^-(SO) and Cl^-(Cl) were prepared by normal neutralization.The obtained ionic liquids were identified by FT-IR and ^1H NMR spectroscopy.However,their properties such as meliting point,conductivity,viscosity etc,were determined.     

过渡元素Dawson结构的钨钒磷四元杂多配合物的合成与表征

制备了两个系列１２种尚未见文献报道的过渡金属Ｄａｗｓｏｎ结构的钨钒磷四元杂多配合物。经元素分析和热重分析确定配合物通式为Ｋ９，１０［Ｐ２Ｍ（Ｈ２Ｏ）Ｗ１５Ｖ２Ｏ６１］．ｘＨ２Ｏ和Ｋ１０，，１１［Ｐ２Ｍ（Ｈ２Ｏ）Ｗ１４Ｖ３Ｏ６１］．ｘＨ２Ｏ）（Ｍ＝Ｆｅ＾３＾＋，Ｃｏ＾３＾＋，Ｎｉ＾２＾＋，Ｍｎ＾２＾＋，Ｃｕ＾２＾＋，Ｚｎ＾２＾＋＿），采用ＩＲ，ＵＶ，ＮＭＲ，ＥＳＲ和ＸＲＤ等方法进行了结构表征。     

碱性介质中二(高碘酸根)合铜(Ⅲ)酸根氧化乙二醇独丁醚的反应动力学及机理

在25℃～40℃区间用分光光度法在碱性介质中研究了二(高碘酸根)合铜(Ⅲ)酸根配离子(DPC)氧化乙二醇独丁醚(EGB)的反应动力学。结果表明:反应对DPC为一级,对EGB是1< n_ap< 2(n_ap代表表观反应级数);在保持准一级条件([EGB]₀ 》[Cu(Ⅲ)]₀)下,表观速率常数,k_obs,在弱碱性介质中,随[OH^-]增大而减小,在较强碱性介质中随[OH^-]增大而增大,随着[IO₄^-]增加而减小;无盐效应。提出了含有自由基过程的反应机理,由假设的两种同时进行的反应机理推出的速率方程能很好的解释全部实验现象,进一步求得速控步的速率常数和活化参数。     

土壤中稀土对有效氮形态分配和转化的影响

在土壤旱作和淹水培养两种方式下, 通过添加外源稀土研究了黄褐土中稀土对有效氮形态分配和转化的影响.结果表明, 在旱培条件下, 土壤中稀土含量的提高增加铵态氮和水解氮的含量, 减少硝态氮的含量, 两周内增加矿质态氮的含量, 八周以后则无显著影响; 有效氮的含量在稀土含量较低时升高, 高含量时则下降, 实验确定外源稀土对旱培土壤有效氮作用的无观察效应浓度(NOEC)为443.8 mg*kg-1. 在淹水培养条件下, 稀土含量较低时对土壤铵态氮和水解氮含量无显著影响, 含量较高时则降低铵态氮和水解氮含量, 外源稀土对淹水土壤铵态氮和水解氮含量影响的无观察效应浓度分别为 171.2, 256.9 mg*kg-1. 分析表明, 土壤中稀土含量的变化对氮素的影响在旱培条件下主要与稀土对土壤硝化过程作用有关, 淹水条件下与稀土对土壤氨化过程作用有关.     

MgCl2载体对Nd(OiPr)3-nCln-HAl(i-Bu)2催化剂性能的影响

对不含ｆ 电子的过渡金属 (Ｔｉ、Ｃｏ、Ｎｉ等 )的Ｚｉｅｇｌｅｒ Ｎａｔｔａ催化剂 ,载体化是提高催化活性的一种重要方法 ,并已经取得了成功[1,2 ] 。而对具有许多独特优点[3] 的稀土Ｚｉｅｇｌｅｒ Ｎａｔｔａ催化剂的载体化 ,虽然人们也做了一些研究[4 ,5] ,并在一定程度上提高了催化效率 (约 2～ 3倍 ) ,但与高效载体催化剂相比 ,其催化效率还是比较低 ,因此有必要进行进一步探索 ,以助于寻找提高催化活性和定向性的途径。1　实验部分1 1　催化剂的制备1 1 1　ＭｇＣｌ2 载体的制备[6] 　将 2 0 0ｇＭｇＣｌ2 ·6Ｈ2 Ｏ与 5 5ｇＮ…     

Solvent-switchable Acetalization by Yb（OTf）3-Catalyzed Procedures

O,O＇Diethyl acetals were prepared in high yields under mild conditions via the reaction of triethyl orthoformate with aldehydes and ketones in absolute ethanol in the presence of as low as 0.1 tool% of Yb（OTf）3. Using the same catalyst in THF-H2O, these O,O＇-diethyl acetals could be converted to the corresponding carbonyl compounds efficiently. This new protection-deprotection protocol presents the advantages of ease of execution, high efficiency and good chemoselectivity.     

Preparation of nanometer-sized In2O3 particles by a reverse microemulsion method

Nanometer-sized indium oxide (In(2)O(3)) particles have been prepared by chemical reaction of inorganic indium compounds and ammonia gas in a reverse microemulsion system consisting of water, Triton X-100 (surfactant), n-heptanol (co-surfactant), and n-octane (oil). Precursor hydroxides precipitated in the droplets of water-in-oil (W/O) microemulsion were calcined at different temperatures to form indium oxide powder. The factors affecting the particle size have been discussed; the calcination temperature is considered to be the important factor for controlling the size. In(2)O(3) calcined at 400 degrees C had a spherical form and a narrow size distribution. Calcination at 800 degrees C led to the formation of particles not only of irregular shape, but also of a wide size distribution. With the increase in calcination temperature from 400 to 800 degrees C, the average size of the particles grew from 7 to about 40 nm. The species of reactants used in the aqueous phase had a significant effect on the size of the particles. The average diameter of In(2)O(3) particles derived from reactant InCl(3) was 7 nm; that of particles derived from In(NO(3))(3) was 15 nm. The In(2)O(3) nanoparticles were characterized by transmission electron microscopy and X-ray diffraction. The phase behavior of the microemulsions is discussed.