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51.
Oxidative α-cyanation of tertiary amines is catalyzed by gold complexes with trimethylsilyl cyanide to afford the corresponding α-aminonitriles in the presence of tert-butyl hydroperoxide in good to excellent yields under acid-free conditions at room temperature.  相似文献   
52.
53.
完成了小型方波脉冲磁场装置的双线圈负载设计,在一定区域内获得了近似匀强磁场。采用阻抗2 的6级脉冲形成网络作为初级储能和脉冲形成单元,对匹配电阻放电产生了方波脉冲电流波形。研制了一种场畸变气体火花间隙作为主放电开关,有效减小了装置的动作时延和分散性。实验结果表明:负载中心峰值磁感应强度达到0.04 T,方波磁场平顶时间约3 s,平顶度小于5%,上升前沿(磁感应强度峰值10%~90%)小于0.5s,装置的动作时延抖动小于10 ns(标准偏差)。  相似文献   
54.
The intramolecular cyclization of o‐alkynylphenylphosphonamide and N‐(o‐alkynylphenyl)acetamide was monitored by electrospray ionization mass spectrometry (ESI‐MS) and its tandem version (ESI‐MS/MS). The proposed intermediates were successfully intercepted and characterized. In addition, the intermediates composed of the substrate coordinated to the palladium(II) center in the reaction of o‐alkynylphenylphosphonamide were unexpected before, and this interesting phenomenon of the substrate coordination seems associated with the unique structure of substrates.  相似文献   
55.
柯庆  高清维  卢一相 《色谱》2018,36(1):59-68
论文提出用积分渐进展开解析气相色谱重叠峰,该方法有3个主要步骤:首先将谷峰或肩峰分成两个积分区域,得到一个子区域的积分方程和一个重叠峰面积的代数方程;然后用数值积分求出这两个方程计算中所需要的峰面积,再用积分渐进公式将积分方程展开成代数方程;最后,将这两个方程与峰高约束方程联立后,得到一个非线性代数方程组,用Gauss-Seidel迭代可以快速求解方程组,方程收敛的最大迭代次数不超过20次。仿真和实验结果表明,解析的峰高和峰面积误差均很小,峰面积最大误差低于6.44%,峰高的最大误差约为6.80%。由于该算法精度高,效率高,所以这个方法可以用于气相色谱重叠峰和一般色谱峰的实时在线解析。  相似文献   
56.
As a typical multiphase fluid flow process, drainage in porous media is of fundamental interest both in nature and in industrial applications. During drainage processes in unsaturated soils and porous media in general, saturated regions, or clusters, in which a liquid phase fully occupies the pore space between solid grains, affect the relative permeability and effective stress of the system. Here, we experimentally study drainage processes in unsaturated granular media as a model porous system. The distribution of saturated clusters is analysed by optical imaging under different drainage conditions, with pore-scale information from Voronoi and Delaunay tessellation used to characterise the topology of saturated cluster distributions. By employing statistical analyses, we describe the observed spatial and temporal evolution of multiphase flow and fluid entrapment in granular media. Results indicate that the distributions of both the crystallised cell size and pore size are positively correlated to the spatial and temporal distribution of saturated cluster sizes. The saturated cluster size is found to follow a lognormal distribution, in which the generalised Bond number (\( Bo^{*} \)) correlates negatively to the scale parameter (μ) and positively to the shape parameter (σ). With further consideration of the total surface energy obtained based on liquid–air interfaces, we were able to include additional grain-scale information in the constitutive modelling of unsaturated soils using both the degree of saturation and generalised Bond number. These findings can be used to connect pore-scale behaviour with overall hydro-mechanical characteristics in granular systems.  相似文献   
57.
A novel system based on the indirect oxy-combustion of coal in a liquid Sb anode solid oxide fuel cell (SOFC) has been used to produce electricity for over 48?h. Pulverized anthracite was fed to the liquid-antimony-anode of the fuel cell, and a peak power density of 47?mW cm?2 was reached at 1023?K and 35?mW cm?2 at 973?K. The fuel cell was prepared using a porous stainless-steel tube as a support for an LSM cathode, antimony oxide (Sb2O3)/yittria stabilized zirconia (YSZ, Y0.08Z0.92O1.96) composite electrolyte (membrane), while liquid antimony acted as the anode. Liquid antimony/antimony oxide served as the intermediate medium for coal oxidation producing mainly carbon dioxide, which evolved as a separate gas stream. The fuel cell will facilitate carbon capture process, and simultaneously convert the chemical energy of coal directly to electricity. The experiment showed that while the fabricated electrolyte was porous, it became dense during the actual operation, preventing nitrogen leakage into the Sb/C side and producing reasonable open circuit voltage. Analysis of the experimental EIS data illustrates that the Ohmic resistance was the primary loss mechanism in the system. It further suggests approaches to improve the design. Continuous operation of this coal fueled oxy-combustion/fuel cell system achieved an overall efficiency of 28.2% despite of its tiny scale. Simple technologies can be employed to scale up this system at relatively low cost of fabrication and materials.  相似文献   
58.
建立了高效液相色谱法测定硫酸伏拉帕沙原料药中杂质的方法.采用ACE Excel C18(4.6 mmx 250 mm,5 pm)色谱柱;以pH 2.5的H3PO4溶液为流动相A,乙腈为流动相B,梯度洗脱;检测波长为260 nm;进样量为20 μL.结果表明,主成分与各杂质的分离度良好,各已知杂质在测定的范围内具有良好的...  相似文献   
59.
半格与Domain的表示   总被引:6,自引:0,他引:6  
陈仪香 《数学学报》1998,41(4):737-742
引入一种半格———D 半格,建立了D-半格的表示理论,利用它得到了L domain(即局部代数格)的表示理论;证明了L domain与稳定映射范畴对偶等价于稳定D 半格与D-半格同态范畴.  相似文献   
60.
ANoteofRegularityonCompletelyDistributiveLattices¥ChenYixiang(XuzhouTeachersCooege,221009)Abstract:Inthisnote,theauthorgivess...  相似文献   
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