The Comparative Study of Reaction Mechanisms and Catalytic Performances of Cu–SSZ-13 and Fe–SSZ-13 for the NH3-SCR Reaction

Catalysis Surveys from Asia - The catalytic performances and mechanism differences of model catalysts Cu–SSZ-13 and Fe–SSZ-13 with similar metal content and Si/Al ratio were compared....     

超声波海水淡化装置的设计研究

针对我军海防士兵淡水补给困难的问题,以超声雾化为基础,结合半导体冷凝技术,提出了一种超声波海水淡化装置的设计思路.并利用Multisim和Matlab仿真软件研究了超声波发射器振荡频率与雾化水雾中盐度之间的关系,为相关设备的后续研制提供了可靠的理论依据.     

Residues and risk assessment of bifenthrin and chlorfenapyr in eggplant and soil under open ecosystem conditions

Dissipation and residue levels of bifenthrin and chlorfenapyr in eggplant and soil under field conditions were investigated using gas chromatography coupled with an electron capture detector (GC-ECD). The mean recoveries of bifenthrin and chlorfenapyr were 85.2–104.9%, with relative standard deviations (RSDs) of 0.5–9.1%. The limit of quantification (LOQ) was 0.01 mg kg^?1. Bifenthrin exhibited half-lives of 3.3 to 4.1 days in eggplant and 17.8 to 25.7 days in soil; the half-lives of chlorfenapyr were 3.5 to 3.8 days in eggplant and 21.7 to 27.7 days in soil. During harvest, the terminal residues of bifenthrin and chlorfenapyr were below 0.031 and 0.083 mg kg^?1, respectively. Risk assessment for different groups of people in China was evaluated. The risk quotients (RQs) of bifenthrin and chlorfenapyr were ranged from 0.0068 to 0.0148 and from 0.0033 to 0.0072, respectively. These results may provide guidance on reasonable use of pesticides and serve as a basis for establishing maximum residue limits (MRLs) in China.     

改进人工蜂群算法优化ELM分类模型

针对极限学习机(Extreme Learning Machine,ELM)参数优化问题,提出改进人工蜂群算法(Improvement Artificial bee colony, IABC)优化ELM分类模型。算法采用解更新策略池代替固定不变的更新策略,将邻域搜索自适应化;优化侦察蜂搜索方式,利用Kent映射产生均匀性更优的初始随机数序列。在分类数据集中,将IABC-ELM分类模型同ELM、PSO-ELM分类模型进行对比实验。实验中,IABC-ELM模型取得了最佳的分类结果,得到了最低的输出权重范数。结果表明,IABC-ELM模型分类效果显著优于对比模型,证实了IABC算法优化ELM分类模型的有效性和优越性。     

滑块碰撞动力学与圆周率的关联

滑块碰撞与圆周率π看似不相关的两个事物却具有某种联系,本文研究了滑块碰撞动力学,利用计算工具MATLAB,发现在理想情况下,滑块的碰撞次数与π有一定的关联,并在理论上证明了计算结果。     

自均衡线性相位高温超导滤波器的设计

针对第三代移动通信CDMA 2000标准用超导滤波器的技术要求,设计了一种自均衡线性相位高温超导滤波器,给出了14阶三个交叉耦合的CQ结构滤波器理论计算结果、等效电路、耦合矩阵,设计的滤波器中心频率为830MHz,65%带宽内的群时延波动优于±10ns,滤波器模拟仿真结果与理论计算很好得吻合。     

Simultaneous determination of five strobilurin fungicides and the metabolite BF-500-3 in cereals,fruits and vegetables

A rapid and sensitive method for the simultaneous determination of five strobilurin fungicides and the metabolite BF-500-3 in cereals (maize and wheat), fruits (grape and apple) and vegetables (cucumber and tomato) was developed by a Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method using high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS). The five strobilurin fungicides (kresoxim-methyl, picoxystrobin, pyraclostrobin, azoxystrobin and trifloxystrobin) and the metabolite BF-500-3 were extracted from six matrices using acetonitrile and subsequently cleaned up by dispersive solid phase extraction (d-SPE) using octadecylsilane (C₁₈) as sorbent prior to HPLC-MS/MS analysis. The determination of the six compounds was achieved in less than 6.0 min using an electrospray ionisation source in positive mode (ESI+). This method showed the linearity with the coefficients of determination (R²) higher than 0.9929. The limits of quantification (LOQs), defined as the lowest spiking level, were 5 μg/kg for all the fungicides in all matrices. Recovery studies were performed at three fortification levels (5, 10 and 100 μg/kg) and the overall average recoveries ranged from 76.9% to 114.2% with the relative standard deviation (RSD) less than 13.6% for all the analytes. The method is demonstrated to be convenient and reliable for the routine monitoring of five strobilurin fungicides and the metabolite BF-500-3 in cereals, fruits and vegetables.     

Near common-path optical fiber interferometer for potentially fast on-line microscale-nanoscale surface measurement

We introduce a new surface measurement method for potential online application. Compared with our previous research, the new design is a significant improvement. It also features high stability because it uses a near common-path configuration. The method should be of great benefit to advanced manufacturing, especially for quality and process control in ultraprecision manufacturing and on the production line. Proof-of-concept experiments have been successfully conducted by measuring the system repeatability and the displacements of a mirror surface.     

Facet Engineering on WO3 Mono-Particle-Layer Electrode for Photoelectrochemical Water Splitting

Photoelectrochemical (PEC) performance of WO₃ photoanodes for water splitting is heavily influenced by the orientation of crystal facets. In this work, mono-particle-layer electrodes, assembled by particulate WO₃ square plates with highly uniform alignment along the (002) facet, improved PEC water oxidation kinetics and stability. Photo-deposition of Au along the cracks formed on the surface of the plates, which are the edges of {110} facets, was found to further enhance electron collection efficiency. Combination of these two strategies allowed the facet-engineered WO₃ electrode to produce significantly higher efficiencies in charge separation and transfer than the electrode prepared without facet orientation. This work has provided a facile route for fabricating a structurally designed WO₃ photoelectrode, which is also applicable to other regularly shaped semiconductor photocatalysts with anisotropic charge migration.