Bromination of 5‐Methoxyindane: Synthesis of New Benzoindenone Derivatives and Ready Access to 7H‐Benzo[c]fluoren‐7‐one Skeleton

The photobromination of 5‐methoxyindane and 5‐methoxyindanone was studied at both high and low temperatures. 1,2,3‐Tribromo‐6‐methoxyindene was easily synthesized by photolytic bromination of 5‐methoxyindane at low temperature. 1,1,2,3‐Tetrabromo‐6‐methoxyindene was obtained from the photobromination of 5‐methoxyindan at 77 °C, which could then be easily converted to the 2,3‐dibromo‐6‐methoxyindene by silver‐supported hydrolysis. Photochemical bromination of 5‐methoxy‐1‐indanone with N‐bromosuccinimide (NBS) gave 3‐bromo‐6‐methoxyindene, which upon thermolysis gave a benzo[c]fluorenone derivative.     

合成盐酸芬戈莫德的工艺改进

以溴苯为原料,经Wurtz偶联反应、Friedel-Crafts反应、烷基化反应等合成了免疫抑制剂盐酸芬戈莫德,总收率23.6%,其结构经1H NMR,IR和ESI-MS确证。     

Determination of the chemical composition and Raman characterization of barite samples from Denizli and Akdamadeni,Turkey, using Energy Dispersive X-ray fluorescence and Raman microscopy

Accurate analysis of samples is very important for scientists working in many fields. XRF device is used very frequently especially in mine analysis. However, researchers are trying to reach accurate results with many different analysis methods. In addition to the known analysis methods, alternative research methods also guide the studies. In this study, two barite ore samples, collected from two regions of different nature (Denizli and Akda?madeni) by following specified sampling methods, were analyzed using Confocal Raman Spectroscopy (CRS) and Polarized Energy Dispersive X-Ray Fluorescence (PEDXRF) spectrometer. The first sample was from a metamorphic basement, and the second was from an alkali syenite rock unit. The main objective of this paper is to compare the optical characteristics of these two different barite samples collected from different regions under a polarized microscope, using CRS and PEDXRF. The results of polarized microscopy analysis showed that the barite taken from Denizli is associated with calcite. On the other hand, the barite taken from Akda?madeni is associated with galena, celestite, and quartz. Two different colors were observed in the barite samples. CRS and PEDXRF results showed that the barites collected from two regions differed in mineral association, chemical composition, and physical properties. The accuracy of the chemical analysis technique was ensured by following USGS standards, GBW 7109, and GBW-7309 Sediment. Barite ores were analyzed using HR-800 (HORIBA-Jobin Yvon) CRS and a polarized microscope (Leica DMLP). Thanks to this study, it has been shown that mineral analyzes can be performed with an accuracy close to XRF with Confocal Raman spectroscopy. Confocal Raman spectroscopy will also guide researchers for mineral analysis.     

单原子铈对弱芬顿效应活性位点氧还原稳定性的提升

合成了同时具备弱芬顿效应活性位点(Ru-N _x )和自由基消除位点(Ce-N _x )的高稳定性电催化剂Ru, Ce-N-C. 电化学性能测试结果表明, 在酸性电解质中, Ru, Ce-N-C催化剂表现出良好的氧还原反应(ORR)活性(半波电位为0.78 V)和稳定性(30000次加速老化测试后, 半波电位仅下降8 mV), 优于Fe-N-C催化剂. 对反应机理的研究发现, Ru, Ce-N-C催化过程中电子转移数为3.98, 平均H₂O₂产率低于5%.     

降低直接甲醇燃料电池浓差极化的含磺化碳管阻水夹层的构建

采用直接接枝法, 将来自对氨基苯磺酸的苯磺酸官能团引入氧化多壁碳纳米管, 制得磺化多壁碳纳米管(SO₃-MCNT). 再以SO₃-MCNT为填料, 以Nafion离聚物为黏结剂, 利用超声喷涂在商业N212质子交换膜一侧构建了新的膜层, 获得了一种复合膜(SO₃-MCNT?N212). 使用SO₃-MCNT?N212制备燃料电池膜电极(MEA), 并用于直接甲醇燃料电池(DMFC)测试. 与使用普通N212膜的膜电极相比, 该膜电极的性能得到明显提升. 进一步分析表明, SO₃-MCNT膜层的引入降低了阳极向阴极的跨膜水迁移作用, 缓解了阴极的水淹, 从而降低了浓差极化, 提升了膜电极的性能.     

Reductive Elimination at Pb(II) Center of an (Amino)plumbylene-Substituted Phosphaketene: New Pathway for Phosphinidene Synthesis

A stable (amino)plumbylene-substituted phosphaketene 3 was synthesized by the successive reactions of PbCl₂ with two anionic reagents (lithium amidophosphine and NaPCO). Of particular interest, the thermal evolution of 3 , at 80 °C, leads to the transient formation of corresponding amino- and phosphanylidene-phosphaketenes ( 6 and 7 ), via a reductive elimination at the Pb^II center forming new N−P and P−P bonds. Further evolution of 6 gives a new cyclic (amino)phosphanylidene phosphorane 4 , which shows a unique reactivity as a phosphinidene. This result provides a new synthetic route to phosphinidenes, extending and facilitating further their access.     

Anode Catalytic Dependency Behavior on Ionomer Content in Direct CO Polymer Electrolyte Membrane Fuel Cell

In this work, the effect of Nafion ionomer content on the structure and catalytic performance of direct CO polymer electrolyte membrane fuel cell(CO-PEMFC) by using Rh-N-C single-atom catalyst as the anode catalyst layers was studied. The ionic plaque and roughness of the anode catalyst layers increase with the increase of Nafion ionomer content. Furthermore, the contact angle measurement results show that the hydrophilicity of the anode catalyst layers also increases with the increase of Nafion ionomer content. However, when the Nafion ionomer content is too low, the binding between microporous layers, catalyst layers and membrane cannot meet the requirement for either electric conductivity or mass transfer. While Nafion ionomer content increased above 30%, the content of water in anode is difficult to control. Therefore, it was found that AN 30(30% Nafion ionomer content of anode) is the best level to effectively extend the three-phase boundary and improve CO-PEMFCs performance.     

An effective approach for numerical solution of linear and nonlinear singular boundary value problems

In this study, an effective approach is presented to obtain a numerical solution of linear and nonlinear singular boundary value problems. The proposed method is constructed by combining reproducing kernel and Legendre polynomials. Legendre basis functions are used to get the kernel function, and then the approximate solution is obtained as a finite series sum. Comparison of numerical results is made with the results obtained by other methods available in the literature. Furthermore, efficiency and accuracy of the method are demonstrated in tabulated results and plotted graphs. The numerical outcomes demonstrate that our method is very effective, applicable, and convenient.     

Simulation of loss of uranium ions due to charge changing processes in the CSRm ring

Significant beam loss caused by the charge exchange processes and ion impact-induced outgassing may restrict the maximum number of accelerated heavy ions during the high intensity operation of an accelerator. In order to control beam loss due to charge exchange processes and confine the generated desorption gas, tracking of the beam loss distribution and installation of absorber blocks with low-desorption rate material at appropriate locations in the main Cooler Storage Ring (CSRm) at the Institute of Modern Physics, Lanzhou, will be performed. The loss simulation of uranium ions with electron-loss is presented in this report and the conclusion is that most charge changed particles are lost in the second dipole of the super-period structure. The calculation of the collimation efficiency of the CSRm ring will be continued in the future.