Selective catalytic reduction of NO by C2H2 over Ce-Al2O3 catalyst with rate-determining step of NO oxidation

Ce-Al2O3 catalysts prepared by co-precipitation are investigated both in NO oxidation by O2 and in selective catalytic reduction of NO by C2H2(C 2 H 2-SCR).It is found that C2H2-SCR is initiated and controlled by NO oxidation to NO 2 over Al2O3.Ce loading on Al2O3 is almost inactive for NO oxidation below 350 C,since NO2 strongly adsorbs on cerium oxide,leading to the active sites being blocked,which was characterized by temperature-programmed desorption of NO and NO 2 and Fourier transform infrared spectroscopy after NO+O 2 coadsorption over the samples.However,in the case of C2H2-SCR,Ce loading on Al 2 O 3 significantly improves the reaction by accelerating the NO oxidation step in the temperature range of 250-450 C,since the nitrate species produced by NO 2 adsorption is an active intermediate required by C2H 2-SCR.     

车辆-轨道系统垂向随机振动的辛方法分析

将轨道视为无限长的周期结构,建立车辆轨道垂向耦合模型. 使用虚拟激励法将随机的轨道不平顺激励转化为确定性的简谐激励,再用辛数学方法求解轨道结构的频率响应特性和耦合系统的响应功率谱. 整个计算模型只有26个自由度,求解过程快速而精确.数值算例中,将该方法与常规有限元方法进行了比较,验证了方法的高效性和正确性,讨论了车辆速度对系统随机响应的影响.      

Simultaneous Determination of Seven Lipophilic and Hydrophilic Components in Salvia miltiorrhiza Bunge by LC-MS/MS Method and Its Application to a Transport Study in a Blood-Brain-Barrier Cell Model

Salvia miltiorrhiza Bunge (SM) has been extensively used in Alzheimer’s disease treatment, the permeability through the blood-brain barrier (BBB) determining its efficacy. However, the transport mechanism of SM components across the BBB remains to be clarified. A simple, precise, and sensitive method using LC-MS/MS was developed for simultaneous quantification of tanshinone I (TS I), dihydrotanshinone I (DTS I), tanshinone IIA (TS IIA), cryptotanshinone (CTS), protocatechuic aldehyde (PAL), protocatechuic acid (PCTA), and caffeic acid (CFA) in transport samples. The analytes were separated on a C18 column by gradient elution. Multiple reaction monitoring mode via electrospray ionization source was used to quantify the analytes in positive mode for TS I, DTS I, TS IIA, CTS, and negative mode for PAL, PCTA, and CFA. The linearity ranges were 0.1–8 ng/mL for TS I and DTS I, 0.2–8 ng/mL for TS IIA, 1–80 ng/mL for CTS, 20–800 ng/mL for PAL and CFA, and 10–4000 ng/mL for PCTA. The developed method was accurate and precise for the compounds. The relative matrix effect was less than 15%, and the analytes were stable for analysis. The established method was successfully applied for transport experiments on a BBB cell model to evaluate the apparent permeability of the seven components.     

Fixed-time SOSM controller design with output constraint

Nonlinear Dynamics - In this paper, a novel fixed-time second-order sliding mode (SOSM) controller has been developed for a class of nonlinear systems with output constraints. Based on the output...     

Na-K liquid alloy:A review on wettability enhancement and ionic carrier selection mechanism

The intrinsic liquid interface of Na-K alloy allays concerns about dendrite growth on metal anodes that are thermodynamically within the room temperature(20-22℃).Nevertheless,it hinders the formation of a stable electrode structure due to the inferior wettability induced by considerable liquid tension.In addition,the dominant ionic carrier in the Na-K alloy is subject to multiple factors,which is not conducive to customized battery design.This review,based on recently reported frontier achievements on Na-K liquid anodes,summarizes practical strategies for promoting the wettability by hightemperature induction,capillary effect,vacuum infiltration,and solid interface protection.Furthermo re,four selection mechanisms of the dominant ionic carrier are presented:(1) ion property dominated,(2)cathode dominated,(3) separator dominated,and(4) solid electrolyte interface dominated.Notably,initial electrolytes in energy storage systems have been unable to play a decisive role in ionic selection.Utilizing a superior wettability strategy and simultaneously identifying the dominant ionic carrier can facilitate the tailored application of dendrite-free Na-K liquid anodes.     

两种菁类染料复合敏化TiO_2纳米晶电极的光电化学研究

应用光电化学方法研究了两种菁类染料Cy3和Cy5复合敏化TiO2纳米晶电极的光电化学行为.结合两种染料的紫外-可见光谱和循环伏安曲线,确定了Cy3和Cy5的电子基态和激发态能级位置.结果表明两种染料的激发态能级位置能与TiO2纳米粒子导带边位置相匹配,复合敏化可以显著提高TiO2纳米晶的光电流,使TiO2纳米晶电极吸收波长由紫外光区红移至可见光区和近红外区.复合敏化降低了染料Cy3 在电极吸附时的聚集程度,使其单色光的转换效率(IPCE)提高了169%,复合敏化电极总的光电转换效率η为2.09%,分别是Cy3和Cy5单独敏化时光电转换效率的2.069 和1.229倍.     

Metal–Organic Framework Membrane Nanopores as Biomimetic Photoresponsive Ion Channels and Photodriven Ion Pumps

Biological ion channels and ion pumps with sub‐nanometer sizes modulate ion transport in response to external stimuli. Realizing such functions with sub‐nanometer solid‐state nanopores has been an important topic with wide practical applications. Herein, we demonstrate a biomimetic photoresponsive ion channel and photodriven ion pump using a porphyrin‐based metal–organic framework membrane with pore sizes comparable to hydrated ions. We show that the molecular‐size pores enable precise and robust optoelectronic ion transport modulation in a broad range of concentrations, unparalleled with conventional solid‐state nanopores. Upon decoration with platinum nanoparticles to form a Schottky barrier photodiode, photovoltage across the membrane is generated with “uphill” ion transport from low concentration to high concentration. These results may spark applications in energy conversion, ion sieving, and artificial photosynthesis.     

Effects of heat treatment and SOC on fire behaviors of lithium-ion batteries pack

Journal of Thermal Analysis and Calorimetry - Numerous lithium-ion battery fire accidents raise comprehensive safety concerns in modern society. In this paper, an experimental study was conducted...     

A High-Yield and Cost-Effective Synthesis of Spirotetramat

Russian Journal of Organic Chemistry - cis-8-Methoxy-1,3-diazaspiro[4.5]decane-2,4-dione, the key intermediate in the synthesis of spirotetramat, was synthesized by catalytic hydrogenation,...     

From β-Na2B6O10 to Na3AlB8O15 and Na3Al2B7O15: Structural Tuning of Anionic-Group Architectures by Substitution of [BO4] by [AlO4] Covalent Tetrahedra

Two new sodium aluminum borates, Na₃AlB₈O₁₅ and Na₃Al₂B₇O₁₅, have been successfully synthesized by the high-temperature solution method. They crystallize in the different space groups, P2₁/c and P2/c, respectively. The B−O configurations of β-Na₂B₆O₁₀, Na₃AlB₈O₁₅ and Na₃Al₂B₇O₁₅ are compared to feature complicated different dimensional open-framework structures caused by the substitution of [BO₄] by [AlO₄] covalent tetrahedra. Moreover, the experimental results indicate that Na₃AlB₈O₁₅ and Na₃Al₂B₇O₁₅ have short ultraviolet (UV) cutoff edges (<187 nm). The first-principles calculations show that Na₃AlB₈O₁₅ and Na₃Al₂B₇O₁₅ have moderate birefringence (0.075 and 0.041@1064 nm, respectively).