Fe-Co-Ni合金纳米线有序阵列的模板合成与磁性

以二次阳极氧化的氧化铝膜为模板，用电化学沉积的方法成功地合成了Fe-Co-Ni三组份有序纳米线阵列.扫描电子显微镜（SEM）和透射电子显微镜(TEM)观察表明纳米线表面光滑、有序、高长径比；磁性测量表明,其矫顽力较同组份的膜材料有较大的提高.将样品在惰性气体氛围中不同温度下退火，随着退火温度增加，其纵向矫顽力有一个极值，而对应的横向矫顽力没有类似的变化，关于这一现象的机理,本文进行了初步的讨论. 图5参15     

Ion Association and Hydration in Aqueous Solutions of Nickel(II) and Cobalt(II) Sulfate

Aqueous solutions of nickel(II) and cobalt(II) sulfate have been investigated at 25 ^∘C by dielectric relaxation spectroscopy (DRS) over a wide range of frequencies (0.2 ≤ ν (GHz) ≤ 89) and salt concentrations (0.025 ≤ c(mol-L⁻¹) ≤ 1.4). The spectra indicate, as for MgSO₄(aq) studied previously, the simultaneous presence of double solvent-separated, solvent-shared and contact ion pairs in both NiSO₄(aq) and CoSO₄(aq). The stepwise formation constants for each ion-pair type and the overall association constant, obtained from the data are in good agreement with ultrasonic relaxation and other estimates. The DR spectra at higher concentrations (c ≥ 0.5 mol-L⁻¹) suggest the existence of a nonlinear triple ion M₂SO₄²⁺(aq). Consistent with the very strong hydration of the salts, which have ‘effective’ hydration numbers approaching 27 at infinite dilution, there are no significant differences in any of the relaxation or thermodynamic parameters for NiSO₄(aq) and CoSO₄(aq), except that the triple ion appears to be somewhat more stable for the latter.     

C_(59)F_(2n)HN(n=1,2)异构体的结构与稳定性的理论研究

分别用MNDO和AM1两种半经验方法,对C59F2nHN (n = 1, 2) 的异构体进行几何构型全优化,结合频率分析及HF/6-31G单点能计算,确定了各异构体的基态结构及其相对稳定性。计算结果表明,C59HN的F加成物的立体选择性规律与C60的不同,最稳定异构体不是1-2加成物。C59F2HN的最稳定异构体是1-4加成的6, 18-或12, 15-异构体; C59F4HN的最稳定异构体是1-4,1-4加成的6, 18; 12, 15-异构体,其能量远小于其它各异构体的能量。N原子取代碳笼骨架C原子后,改变了碳笼F加成物的立体选择性规律。     

添加非金属元素Si对固体超强酸SO_4~(2-)/TiO_2的改性研究

采用共沉淀法引入Ｓｉ对ＳＯ２－４／ＴｉＯ２进行改性，制得了ＳＯ２－４／Ｔｉ－Ｓｉ－Ｏ系列固体超强酸，试样经ＩＲ、ＳＥＭ、ＸＲＤ表征和低温正戊烷异构化活性测试，发现超强酸中心是硫酸根离子与金属原子Ｔｉ结合形成的双配位螯合结构，在超强酸性的样品中ＴｉＯ２均呈锐钛矿晶型。引入Ｓｉ仅迟滞ＴｉＯ２晶化过程，控制Ｓｉ在ＳＯ２－４／Ｔｉ－Ｓｉ－Ｏ体系中的含量可以有效调节固体超强酸的酸性，并提高正戊烷异构化反应的选择性。     

煤炭码头船货匹配下泊位动态分配多目标优化模型及算法

本文针对输出型煤炭码头船货匹配下泊位动态分配问题,构建了堆场-取装线-泊位-船舶联合分配优化数学模型,并设计了采用仿真推演策略解码的遗传算法求解。首先,综合考虑船舶、泊位、堆场、取装线、煤种、航道开放时间和装船作业规则等要素,以船舶在港时间最短和作业效率最大为目标建立了相应的多约束多目标优化模型。然后,综合多目标优化、遗传算法以及仿真推演技术,设计了相应的遗传算法求解,包括:组合式编码、采用仿真推演策略的解码方法,追加了具有合法性检查的染色体生成算法,设计了采用多种策略的遗传操作等。最后实例表明,本算法的执行效率高而且优化效果好。     

Kurdyka–Łojasiewicz Exponent via Inf-projection

Foundations of Computational Mathematics - Kurdyka–Łojasiewicz (KL) exponent plays an important role in estimating the convergence rate of many contemporary first-order methods. In...     

Regiospecifically controlled formation of tetrasubstituted tributyltin ketone enolates catalyzed by a palladium complex

The palladium-catalyzed hydrostannolysis of α-disubstituted allyl β-keto esters yields the corresponding tributyltin β-keto carboxylates which loose carbon dioxide at very moderate temperature, thus leading to the regiospecific formation of tributyltin tetrasubstituted enolates.