A review of recent advances in selective catalytic NOx reduction reactor technologies

Research on NOx treatment is extensive in recent years due to growing environmental awareness. Selec- tive catalytic reduction （SCR） of NOx, as a proven technology, offers higher NOx control efficiency than many other NOx treatment methods. The present work reviews the recent development of SCR reactor technologies. Firstly, catalysts and mechanism of different SCRs were briefly summarized. Different SCR reactors, e.g. structured reactor, fluidized bed reactor and moving bed reactor, were then discussed. As a more advanced technology, multifunctional reactors were also developed for SCR process and could be divided into two categories： decoupled adsorption-reaction process and combined SCR system. The mechanism and properties of these processes were discussed in detail. Some recommendations were given for the future work in SCR reactor design. SCR reactor technology for emerging energy processes was also addressed, such as oxyfuel combustion and biofuel conversion processes, which put forward new requirements for SCR technologies and also open new opportunities for advanced design of SCR reactors.     

Co/SBA-16:对柴油组分有高选择性的费托合成催化剂(英文)

使用浸渍法制备了一系列Co/SBA-16催化剂,并通过氮物理吸附、X射线衍射、氢程序升温还原、氢化学吸附和透射电镜技术对催化剂行了表征。研究表明,随着负载钴含量的增加,金属钴的分散度降低了,这是同Co3O4晶粒增长和比表面积降低相一致的。Co/SBA-16催化剂展示了高的一氧化碳转化率,低的C1选择性和高的C5+选择性,特别对柴油组分有高选择性。     

超导磁共振仪器设备国产化现状及挑战

磁共振在化学分析和医学影像等领域发挥着不可或缺的作用，而磁共振仪器设备是开展磁共振研究的必要前提.长期以来，国外仪器厂商在我国磁共振仪器市场居于垄断地位.近年来，随着我国在磁共振仪器研发和产业化方面不断取得进展，市场份额为外商垄断的局面已大为改观.本文调研综述了我国磁共振仪器设备研制的现状，以及面临的若干挑战.     

Ab initio investigation of possible lower-energy candidate structure for cationic water cluster (H2O) 12+ via particle swarm optimization method

Detecting the underlying performance of hydrated electrons and hydroxyl radicals in the cationic water cluster can greatly help to understand the inter reaction mechanism in the liquid water and aqueous solutions. Based on our previous (H₂O)₁₀⁺ research, we have paid attention to more problems of larger cationic clusters in this work, including the existence of hemibonded type, long-range correction functions, and hydrogen-bonded site analyses. The lower-energy structures of the cationic water cluster (H₂O)₁₂⁺ have been comprehensively explored, and more experienced functions are introduced to check the ground state and vibration spectrum. Unlike the configuration regularity of neutral (H₂O)₁₂ clusters and small cationic water clusters, those new-found structures for (H₂O)₁₂⁺ are inclined to adopt three dimension (3D) cage-like structures and the H₂O-OH₂ structure appears in the higher energy isomer. The calculation reveals that the lowest stable isomer is the 3D cage structure W14 predicted at MP2 level, which has not been reported yet. In the thermal simulation, structure transition from the cage-like to the ring-like occurs at T?>?≈256 K, and the two dimension (2D) ring-like structure occupies a dominant position at high temperature range. The infrared spectra explain that the difference of the spectra between the 2D net structures and 3D cage-structures is mainly caused by the weight fluctuation of single acceptor-single donor (AD), double acceptor-single donor (AAD), and single acceptor-double donor (ADD) sites in these isomers. This further gives a similarity relation between (H₂O)₁₂⁺ and H⁺(H₂O)₁₂ clusters in the shape of the network and spectral characteristics. By molecular orbitals and topological analysis, we find that the lone pair orbital on hydroxyl radical dominates the reactivity and stability of cationic system. The present research may be helpful for exploring the evolution law of the larger cationic water clusters in the future.

     

Synthesis,characterization, photophysical,and redox properties of three trinuclear Ru(II) polypyridyl complexes possessing 5-amino-1,10-phenanthroline ligands

Three ruthenium(II) polypyridyl complexes with 5-amino-1,10-phenanthroline ligands have been successfully designed and synthesized. They have been fully characterized by ESI-MS, ESI-HRMS, ¹H NMR, and elemental analyses. The photophysical and electrochemical properties of the three complexes have been investigated in organic solvent. The geometrical configuration and the electron density distribution in the frontier molecular orbitals of the three complexes have been studied. The three complexes show metal-to-ligand charge transfer (¹MLCT) absorption at 445 nm, and intense triplet metal-to-ligand (³MLCT) emission at around 619 nm in fluid solution at 298 K and 580 nm in low-temperature glass. Electrochemical studies of the three complexes are consistent with one Ru^III/II reversible couple at around 1.31 V accompanied by three ligand-centered reduction couples.

     

Catalyst-controlled diastereoselective ring-opening formal [3+2]-cycloadditions of arylvinyl oxirane 2,2-diesters with cyclic N-sulfonyl imines

A diastereoselectivity-controllable formal [3+2]-cycloaddition of arylvinyl oxirane 2,2-diesters with cyclic N-sulfonyl imines is developed, affording the corresponding tricyclic oxazolidine derivatives in moderate to excellent yields with excellent diastereoselectivities in the presence of palladium(0) or scandium(III) triflate. This protocol allows selective synthesis of diastereomers of tricyclic oxazolidine derivatives under switchable and mild conditions. Further transformations of the obtained products were conducted by removing ester groups and arylvinyl moieties.     

Side-on-End-on Coordination of Dinitrogen on a Polynuclear Vanadium Nitride Cluster Anion [V5N5]−

The side-on-end-on coordination of N₂ can be very important to activate and functionalize this very stable molecule. However, such coordination has rarely been reported. This study reports a gas-phase species (a polynuclear vanadium nitride cluster anion [V₅N₅]⁻) that can capture N₂ efficiently (12 %), and the quantum chemistry modelling suggests an unusual side-on-end-on coordination. The cluster anions were generated by laser ablation and the reaction with N₂ has been characterized by mass spectrometry, photoelectron imaging spectroscopy, and density functional theory calculations. The back-donation interactions between the localized d–d bonding orbitals on the low-coordinated dual metal (V) sites and the antibonding π* orbitals of N₂ are the driving forces to adsorb N₂ with a high binding energy (about 2.0 eV).     

无人机视角下的林木爆燃火特性研究

森林火灾“爆燃”现象的特征是突然发生的高强度、高蔓延速度的燃烧。目前为止，关于“爆燃火”的原因还没有达成共识。以无人机视角下对林木爆燃火特性研究，以四川木里特大森林火灾为研究对象，通过分析凉山州某森林扑火部队3月31日木里森林火灾当天KWT（科卫泰）无人机航拍火场画面，结合无人机实时影像及实地调研数据，分析了峡谷地形林火蔓延时空特征，探讨了峡谷中风向风速变化时空分布规律，研究了地形变化条件下，不同海拔高度风速特征，建立了无人机倾角测量风速模型（其中为风速m·s-1，为无人机倾角°）。结果表明，高山峻岭特殊地形环境下每天4:00—12:00时间段为静风期，为峡谷林火扑救最佳时期；午后15:00—17:00和晚上20:00—22:00为山谷地形风速活跃期；仿真软件数据显示山顶、谷底与山腰不同海拔位置的风速风向不统一，谷底会产生乱流现象，且风速与海拔不存在正相关关系，小气候在复杂地形中占主导影响地位；在谷口至山谷深处的中间位置会出现气流速度的波峰状态，并易形成乱流，为爆燃火发生提供了客观必要条件。该研究可为复杂地形环境下，森林草原火灾扑救安全提供数据和技术支撑。     

Synthesis,crystal structure,DNA/bovine serum albumin binding and antitumor activity of two transition metal complexes with 4‐acylpyrazolone derivative

Two new complexes, namely [Cu₆L₆] ( 1 ) and [Zn(HL)₂] ( 2 ) (H₂L = N‐(1‐phenyl‐3‐methyl‐4‐propenylidene‐5‐pyrazolone)‐2‐furancarboxylic acid hydrazide), have been synthesized and characterized. Single crystal X‐ray analysis indicates that complex 1 has a hexanuclear structure and complex 2 exhibits a mononuclear structure. The DNA/bovine serum albumin (BSA) binding properties of complexes 1 and 2 were investigated by absorption spectroscopy and fluorescence quenching. Both complexes could effectively intercalate to DNA with calculated quenching constants of 2.6 × 10⁵ and 1.25 × 10⁵ M^?1, respectively. The quenching mechanism of the intrinsic fluorescence of BSA by the complexes was found to be a static one. The cytotoxicities of 1 and 2 were investigated in two human tumor cell lines, human esophageal cancer cells (Eca‐109) and cervical cancer cells (HeLa). Complex 1 exhibits higher antitumor activity than 2 . Furthermore, 1 can inhibit HeLa cells by inducing apoptosis and G0/G1 phase cell cycle arrest. All results demonstrate that 1 and 2 both have DNA/BSA binding capacity and antitumor activity.