烯胺酮α-官能团化反应的研究进展

烯胺酮是一类非常重要的有机合成砌块,具有易获得、储存方便、反应多样性等优点.更重要的是,烯胺酮是许多杂环化合物的重要前体.最近,通过C—H活化对烯胺酮进行过渡金属催化或无过渡金属的α-官能团化反应已成为构建官能化烯胺酮或杂环化合物的一种更为原子和步骤经济的策略,并引起了许多有机化学家的关注.根据成键类型,该综述分为五个部分:C—C键的形成、C—O键的形成、C—N键的形成和C—X键的形成以及C—S/C—Se键的形成.主要对烯胺酮α位官能团化反应进行了综述,从反应机理、反应体系、底物范围等角度系统地综述了烯胺酮α位官能团化反应的进展.     

煤催化气化条件下不同煤种煤灰烧结行为研究

选取9类典型煤种,利用压差法测定烧结温度的实验装置,结合灰渣的XRD分析结果,考察了添加K基碱金属催化剂、不同煤种灰成分对烧结温度的影响。结果表明,碳酸钾催化剂的添加,明显降低高铁钙含量的WJT煤的灰熔点及烧结温度,碱金属K化合物极易同煤中Fe、Ca的矿物质反应生成低温共融物进而加剧煤灰的熔融结渣。不同煤种烧结温度的差异与煤灰中硅、铝、铁、钙含量密切相关。铝、硅含量高的煤灰烧结温度较高,而铁、钙含量高的煤灰烧结温度相对较低。碱金属K催化剂的添加加剧了煤灰的烧结结渣,而钙、铁的存在会加速硅铝酸盐间的反应生成低温共融物进而加速灰熔融。各煤种烧结温度的变化与其灰成分在CaO-SiO₂-Al₂O₃、FeO-SiO₂-Al₂O₃三元相图上的位置相吻合。     

UTSA-280的氨改性以及C2H4/C2H6分离性能研究

炼厂干气中回收乙烯是扩宽C₂H₄来源的有效途径,但C₂H₄和C₂H₆物理性质和分子尺寸非常接近,分离困难.金属有机骨架材料（MOFs）近年来在低碳烃分离领域展现出广阔的前景.本工作采用氨吸附改性调节UTSA-280的结构,通过一维直孔道大小的调节实现C₂H₄/C₂H₆的高效分离.改性后的UTSA-280具有独特的超微孔结构能提升C₂H₄的吸附,而完全不吸附稍大的C₂H₆,实现理想的C₂H₄/C₂H₆吸附选择性（>1000）.结果表明,改性后的UTSA-280的C₂H₄吸附量可提高至2.83 mmol/g,与未改性的材料相比增加29%,并且能阻挡C₂H₆的吸附,最终达到>1200的C₂H₄/C₂H₆选择性.蒙特卡罗分子模拟（GCMC）计算C₂H₄/C₂H₆混合气体（1：1）的吸附得出,改性后UTSA-280孔内的C₂H₄吸附相比于C₂H₆具有更多的吸附分布.通过C₂H₄/C₂H₆混合气体穿透实验测试,改性后的UTSA-280材料能展现出48 min以上的分离时间,相比于未改性的材料,分离性能提升近1倍.     

Effect of noncircular orifice plates on the near flow field of turbulent free jets

In this paper, we experimentally investigate the near-field flow characteristics of turbulent free jets respectively issued from circular, triangular, diamond, rectangular, and notched-rectangular orifice plates into air surroundings. All the orifice plates have identical opening areas or equivalent diameters（De） and their aspect ratios（AR） range from 1 to 6.5. Planar particle image velocimetry（PIV） is used to measure the velocity field at the same Reynolds number of Re = 5 × 10^4,where Re = Ue De/ν with Ue being the exit bulk velocity and ν the kinematic viscosity of fluid. The mean and turbulent velocity fields of all the five jets are compared in detail. Results show that the noncircular jets can enhance the entrainment rate, reflected by the higher acceleration rates of mean velocity decay and spread, shorten the length of the unmixed core,expedite the increase of turbulent intensity compared with the circular counterpart shortened unmixed core, and increase turbulent intensity comparing to the circular counterpart. Among the five jets, the rectangular jet（AR = 6.5） produces the greatest decay rate of the near-field mean velocity, postpones the position at which the 鈥榓xis-switching鈥檖henomenon occurs. This supports that axis switching phenomenon strongly depends on jet initial conditions. In addition, the hump in the centerline variation of the turbulence intensity is observed in the rectangular and triangular jets, but not in the circular jet, nor in diamond jet nor in notched-rectangular jet.     

Solutions of novel soliton molecules and their interactions of (2 + 1)-dimensional potential Boiti-Leon-Manna-Pempinelli equation

The method of variable separation has always been regarded as a crucial method for solving nonlinear evolution equations. In this paper, we use a new form of variable separation to study novel soliton molecules and their interactions in (2+1)-dimensional potential Boiti-Leon-Manna-Pempinelli equation. Dromion molecules, ring molecules, lump molecules, multi-instantaneous molecules, and their interactions are obtained. Then we draw corresponding images with maple software to study their dynamic behavior.     

连续氢化物发生端视ICP-AES法测定水中痕量硒和汞

报道了用自制的在线氢化物连续发生装置,应用端视ICP-AES法测定水中痕量硒和汞。不需要专用氢化物发生装置,分析成本低。在完成非氢化法测定或氢化法测定时不需拆卸或安装。方法简便、快速。测定水中硒和汞的测定,其检出限分别为2×10-4和1×10-4mg·L-1。     

两相流有限穿越可视图演化动力学研究

针对小管径两相流流动特性, 全新优化设计弧形对壁式电导传感器. 通过动态实验在获取传感器测量信号的基础上, 采用有限穿越可视图理论构建对应于不同流型的两相流复杂网络. 通过分析发现, 有限穿越可视图网络异速生长指数和网络平均度值的联合分布可实现对小管径两相流的流型辨识; 有限穿越可视图度分布曲线峰值可有效刻画与泡径大小分布相关的流动物理结构细节特征; 网络平均度值可表征流动结构的宏观特性; 网络异速生长指数对流体动力学复杂性十分敏感, 可揭示不同流型演化过程中的细节演化动力学特性. 两相流测量信号的有限穿越可视图分析为揭示两相流流型的形成及演化动力学机理提供了新途径. 关键词： 两相流 复杂网络 有限穿越可视图 网络异速生长指数     

Hexagonal Standing-Wave Patterns in Periodically Forced Reaction-Diffusion Systems

The periodically forced spatially extended Brusselator is investigated in the oscillating regime. The temporal response and pattern formation within the 2：1 frequency-locking band where the system oscillates at one half of the forcing frequency are examined. An hexagonal standing-wave pattern and other resonant patterns are observed. The detailed phase diagram of resonance structure in the forcing frequency and forcing amplitude parameter space is calculated. The transitions between the resonant standing-wave patterns are of hysteresis when control parameters are varied, and the presence of multiplicity is demonstrated. Analysis in the framework of amplitude equation reveals that the spatial patterns of the standing waves come out as a result of Turing bifurcation in the amplitude equation.     

三维热传导型半导体器件瞬态模拟问题的Crank—Nicolson差分—流线扩散有限元法及其数值分析

本文研究三维热传导型半导体器件瞬态模拟问题的数值方法。针对数学模型中各方程不同的特点，分别提出不同的有限元格式。特别针对浓度方程组是对流为主扩散问题的特点，使用Crank-Nicolson差分-流线扩散计算格式，提高了数值解的稳定性。得到的L^2误差估计关于空间剖分步长是拟最优的，关于时间步长具有二阶精度。     

CVG-ICP-AES法测定饮用天然矿泉水中痕量铅和汞

自制化学蒸气发生器并建立了KBrO3KBr K3Fe(CN)6HCl KBH4的CVG ICP AES同时直接测定饮用天然矿泉水中痕量铅和汞的方法,该方法提高了灵敏度,改善了检出限。方法的检出限分别为0.7μg·L-1(Pb220.353nm),0.1μg·L-1(Hg184.950nm),相对标准偏差分别为0.8%～7.8%(Pb)和0.5%～6.2%(Hg);回收率分别为90.0%～100.0%(Pb)和92.8%～108.0%(Hg)。方法完全能满足饮用天然矿泉水中痕量铅和汞的分析。