Cofeeding of Methane and Ethane to Produce Syngas over a LiLaNiO/γ-Al_2O_3 Catalyst

There are abundant supplies of mixture gases containing CH, and C,H, from natural gas,FCC (Fluidized Catalytic Cracking) dry gas, refinery gas, elc. Commonly, the amount ofC,H, is relatively lower than that of CH,. With regard to the utilization of methane,partial oxidation of methane to syngas over nickel based catalysts has received intensiveallention l'2. For mixture gases containing CH# and C,H,, their conversion to syngas isalso of significance (but has not gained adequate attentio…     

Synthesis and catalytic activity of neutral salicylaldiminato nickel(II) complexes bearing a single N-heterocyclic carbene ligand

Neutral salicylaldiminato Ni(II) complexes bearing a single N-heterocyclic carbene (NHC) ligand [3,5-^tBu₂-2-(O)C₆H₂CHNAr]Ni(C{RNCHCHNⁱPr})Ph [Ar = 2,6-ⁱPr₂C₆H₃, R = Bn (1); Ar = 2,6-ⁱPr₂C₆H₃, R = ⁱPr (2)], have been synthesized via a one-pot procedure in high yield. The X-ray structure analysis reveals that both of 1 and 2 adopt distorted square-planar coordination geometry and NHC carbon (C_carbene) is trans to the ketimine nitrogen. Preliminary study indicates that complex 1 is inert toward the insertion of ethylene, however, it can catalyze the dimerization of ethylene in the presence of modified methylaluminoxane (MMAO) with a moderate activity of 3.05 × 10⁴ g(mol Ni)⁻¹ h ⁻¹ atm⁻¹ in a highly selective fashion.     

Separation of electrical and optical energy gaps for constructing bipolar organic wide bandgap materials

An electrical and optical energy gaps separation strategy is put forward for the design of organic wide bandgap semiconductors. This new principle could achieve optimization of wide bandgap (both high singlet and triplet energies) and favorable carrier injection energy levels simultaneously.     

Iodate Sensing Electrodes Based on Phosphotungstate‐ Doped‐Glutaraldehyde‐Cross‐Linked Poly‐L‐lysine Coatings

Glassy carbon electrode modified with phosphotungstate‐doped‐glutaraldehyde‐cross‐linked poly‐L ‐lysine (PLL‐GA‐PW) film was employed for iodate determination. The PLL‐GA‐PW film electrode shows excellent electrocatalytic activity towards iodate reduction with significant reduction of overpotential. Under optimized experimental conditions, a linear range from 5×10^?8 to 2.27×10^?2 M with a sensitivity of 61.75 μA mM^?1 was obtained. Possible interfering species, in iodate determination, were evaluated and the applicability of proposed sensor for iodate estimation in table salt was also demonstrated. The PLL‐GA‐PW film electrode shows fast response, wider linear range, and good selectivity and stability.     

斜角入射沉积法制备渐变折射率薄膜的折射率分析

斜角入射沉积法是一种制备薄膜的新颖方法,它可以用来制备渐变折射率薄膜.本文首先探讨了膜料的沉积入射角为α,薄膜柱状生长倾斜角为β时的薄膜的填充系数;之后利用drude理论,分析研究了斜角入射沉积法制备渐变折射率薄膜的折射率与薄膜的入射角和生长方向的关系. 关键词： 斜角入射沉积 渐变折射率 填充系数     

引信用激光与加速度传感器复合定高技术

比较了不同类型的弹载定高体制,提出了脉冲激光与重力加速度传感器复合定高的定距原理,并对测距误差进行深入分析,得出其定高精度。对设计出的原理样机进行了实验测试,平台倾斜角度检测实验的结果表明,静态条件下最大角度误差小于0.3;0~500 m定高测试实验的结果表明,测量平均值与实际值最大误差为2.5 m,并且与目标距离无关。     

多相移DFB激光器的单模稳定性分析

本文分析了多相移激光器的稳态特性.在我们的分析中,考虑了空间烧孔(SHB)及非线性增益的因素.在通用的传输矩阵法(TMM)的基础上,我们对TMM模型的输入进行向量处理(而不是用牛顿 拉斐森法(NR))来求阈值及高于阈值条件下的主模及次模,进而求出单模稳定性.这个方法也可用于其它DFB结构的模分析.     

Cationic Pd(II)-catalyzed enantioselective cyclization of aroylmethyl 2-alkynoates initiated by carbopalladation of alkynes with arylboronic acids

A cationic palladium(II)-catalyzed enantioselective intramolecular addition of vinylpalladium species to ketones initiated by the carbopalladation of alkynoates under mild conditions without a Pd(II)/Pd(0) redox system was developed with high yield and enantioselectivity. This cascade reaction provides an efficient method for the construction of optically active hydroxylactones.     

新时代背景下大学物理基础课程教学的讨论

本文讨论的是＂以怎样的理念实施大学物理基础课程教学,才能使学生的学习训练获得最大收益＂.文章首先回顾近30年来教学思想随时代发展的变化,然后提出新时代背景下大学物理基础课程教学＂以学生为中心,使广大学生在知识、能力、素质上获得全面提高＂的新理念.     

Multi-wavelength mode-locked Er/Yb Co-doped fiber laser with square nano-second pulse output

We report a multi-wavelength mode-locked Er/Yb codoped fiber laser with square nano-second pulse output, which is constructed with a “figure-of-eight” cavity structure. A section of polarization-maintaining Er/Yb co-doped double clad fiber was used as the gain medium and pumped by a fiber pigtailed multimode laser diode working at 975 nm via a multimode fiber combiner. Several megahertz repetition rate output pulses with peak power up to 9.2 W and pulse duration around several nanoseconds were obtained.