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Effect of copper precursors on the catalytic performance of Cu-ZSM-5 catalysts in N2O decomposition

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Chinese Journal of Chemical Engineering 2018年第5期26卷 1051-1058页

作者： tao meng Nan Ren Zhen Ma School of Chemical and Environmental Engineering Shanghai Institute of Technology Shanghai 201418 China Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP^3) Department of Environmental Science and Engineering Fudan University Shanghai 200433 China Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Department of Chemistry Fudan University Shanghai 200433 China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092 China

Five Cu-ZSM-5 catalysts were obtained by treating Na-ZSM-5 （Si/Al ratio = 15） with aqueous solutions of differ- ent Cu precursors （CuCl2, Cu（NO3）2, CuSO4, Cu（CH3COO）2, and ammoniacal copper （II） complex ion）. After being pretreated in flowing He at 500 ℃ to form active Cu＋, these catalysts exhibited quite different activities in cata- lytic decomposition of N2O. CZM-AC（II）（prepared by ammoniacal copper （II） complex ion） with 9.4 wt% Cu con- tent was the most active among these Cu-ZSM-5 catalysts, achieving almost complete N2I conversion at 400 ℃. CZM-CA （prepared using Cu（ CH3COO）2 as the Cu precursor） with 2.8 wt% Cu content was the second most active catalyst among these Cu-ZSM-5 catalysts, achieving almost complete N2I conversion at 425 ℃. CZM-CC, CZM- CN, and CZM-CS prepared by using CuCl2, Cu（NO3）2, or CuSO4 as the Cu precursor with similar Cu contents （≈1.7 wt%） were the least active among these Cu-ZSM-5 catalysts, achieving ca. 90% N2O conversion at 500 ℃. XRD, ICP, SEM, TEM, EDX-mapping, and CO-IR experiments were conducted to characterize relevant samples. The superior activity of CZM-AC（II） can be attributed to the high contents of total Cu＋ and dimeric Cu＋ among these samples. The influence of co-fed O2 or H2O on the catalytic performance of typical samples was also studied.

关键词： Copper precursor Cu-ZSM-5 N2O decomposition Catalysis Catalyst Zeolite

3-restricted connectivity of graphs with given girth

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Applied Mathematics(A Journal of Chinese Universities) 2008年第3期23卷 351-358页

作者： GUO Li-tao meng Ji-xiang College of Math. and Sys. Sci. Xinjiang Univ. Xinjiang 830046 China

Let G = （V, E） be a connected graph. X belong to V（G） is a vertex set. X is a 3-restricted cut of G, if G- X is not connected and every component of G- X has at least three vertices. The 3-restricted connectivity κ3（G）（in short κ3） of G is the cardinality of a minimum 3-restricted cut of G. X is called κ3-cut, if ｜X｜ = κ3. A graph G is κ3-connected, if a 3-restricted cut exists. Let G be a graph girth g ≥ 4, κ3（G） is min{d（x）＋ d（y）＋ d（z） - 4 ： xyz is a 2-path of G}. It will be shown that κ3（G） = ξ3（G） under the condition of girth.

关键词： 3-restricted cut 3-restricted connectivity girth

Developing silicon-based photocathodes for CO_(2) conversion

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Science China Chemistry 2024年第6期67卷 1904-1921页

作者： Weijie Zhuang Miao Kan tao meng Jinlong Zhang Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering Feringa Nobel Prize Scientist Joint Research CenterSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai200237China Shanghai Engineering Research Center for Multimedia Environmental Catalysis and Resource Utilization East China University of Science and TechnologyShanghai200237China

Photoelectrochemical(PEC)conversion of CO_(2) presents a promising avenue for solar-driven chemical fuel production,with silicon emerging as a cost-effective and high-light-absorbing material pivotal to this *** at exploring opportunities for industrializing PEC CO_(2) reduction(PEC-CO_(2)R)by minimizing reaction energy consumption,enhancing reaction efficiency and selectivity,this review summarizes recent advancements in developing Si-based photocathodes for PEC-CO_(2)*** outlines the fundamental principles,advantages,and limitations of Si photocathodes with key performance *** on this understanding,the strategies to enhance the performance of the PEC-CO_(2)R system,including light absorption,charge separation,and catalytic reactions are categorized as the interfacial modification,active site decoration,and protective layer *** design ideas of this advantageous three-layer structure in promoting the efficiency,stability,and selectivity have been ***,this review scrutinizes the influence of the photocathodic chemical *** review consolidates the mechanism insights and notable breakthroughs of various fuel generation processes within Si-based PEC-CO_(2)R *** this wealth of information offers an up-to-date perspective on the dynamic developments in silicon-based PEC-CO_(2) conversion and underscores the promising pathways toward the sustainable fuel synthesis from pollutant CO_(2).

关键词： photoelectrochemistry solar fuels silicon photocathodes carbon dioxide reduction microenvironment

Attitude stabilization of a pico-satellite by momentum wheel and magnetic coils

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第11期10卷 1617-1623页

作者： tao meng Hao WANG Zhong-he JIN Ke HAN Department of lnformation Science & Electronic Engineering Zhejiang University Hangzhou 310027 China

The three-axis active attitude control method with a momentum wheel and magnetic coils for a pico-satellite is considered. The designed satellite is a 2.5 kg class satellite stabilized to nadir pointing. The momentum wheel performs a pitch-axis momentum bias, nominally spinning at a particular rate. Three magnetic coils are mounted perpendicularly along the body axis for precise attitude control through the switch control mechanism. Momentum wheel start up control, damping control and attitude acquisition control are considered. Simulation results show that the proposed combined control laws for the pico-satellite is reliable and has an appropriate accuracy under different separation conditions. The proposed strategy to start up the wheel after separation from the launch vehicle shows that its pitch momentum wheel can start up successfully to its nominal speed from rest, and the attitude convergence can be completed within several orbits, depending on separation conditions.

关键词： Pico-satellite Attitude control Magnetic coils Momentum wheel

Damage assessment of aircraft wing subjected to blast wave with finite element method and artificial neural network tool

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Defence Technology（防务技术） 2023年第7期25卷 203-219页

作者： meng-tao Zhang Yang Pei Xin Yao Yu-xue Ge School of Aeronautics Northwestern Polytechnical UniversityXi'an710072ShaanxiChina

Damage assessment of the wing under blast wave is essential to the vulnerability reduction design of aircraft. This paper introduces a critical relative distance prediction method of aircraft wing damage based on the back-propagation artificial neural network(BP-ANN), which is trained by finite element simulation results. Moreover, the finite element method(FEM) for wing blast damage simulation has been validated by ground explosion tests and further used for damage mode determination and damage characteristics analysis. The analysis results indicate that the wing is more likely to be damaged when the root is struck from vertical directions than others for a small charge. With the increase of TNT equivalent charge, the main damage mode of the wing gradually changes from the local skin tearing to overall structural deformation and the overpressure threshold of wing damage decreases rapidly. Compared to the FEM-based damage assessment, the BP-ANN-based method can predict the wing damage under a random blast wave with an average relative error of 4.78%. The proposed method and conclusions can be used as a reference for damage assessment under blast wave and low-vulnerability design of aircraft structures.

关键词： Vulnerability Wing structural damage Blast wave Battle damage assessment Back-propagation artificial neural network

Fractional Fourier domain analysis of decimation and interpolation

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Science in China(Series F) 2007年第4期50卷 521-538页

作者： meng XiangYi tao Ran WANG Yue Department of Electronic Engineering Beijing Institute of Technology Beijing 100081 China

The sampling rate conversion is always used in order to decrease computational amount and storage load in a system. The fractional Fourier transform （FRFT） is a powerful tool for the analysis of nonstationary signals, especially, chirp-like signal. Thus, it has become an active area in the signal processing community, with many applications of radar, communication, electronic warfare, and information security. Therefore, it is necessary for us to generalize the theorem for Fourier domain analysis of decimation and interpolation. Firstly, this paper defines the digital frequency in the fractional Fourier domain （FRFD） through the sampling theorems with FRFT. Secondly, FRFD analysis of decimation and interpolation is proposed in this paper with digital frequency in FRFD followed by the studies of interpolation filter and decimation filter in FRFD. Using these results, FRFD analysis of the sampling rate conversion by a rational factor is illustrated. The noble identities of decimation and interpolation in FRFD are then deduced using previous results and the fractional convolution theorem. The proposed theorems in this study are the bases for the generalizations of the multirate signal processing in FRFD, which can advance the filter banks theorems in FRFD. Finally, the theorems introduced in this paper are validated by simulations.

关键词： decimation interpolation fractional Fourier transform sampling rate conversion the digital frequency in the fractional Fourier domain

Distribution Patterns and Associations of Dominant Tree Species in a Mixed Coniferous-Broadleaf Forest in the Changbai Mountains

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Journal of Mountain Science 2015年第3期12卷 659-670页

作者： ZHANG meng-tao KANG Xin-gang meng Jing-hui ZHANG Li-xin Key Laboratory for Silviculture and Conservation Ministry of Education Beijing Forestry University Yunnan Forest Institute

In 2012 a plot was established with 1-ha area in a mixed coniferous-broadleaf forest in the Changbai Mountains, northeastern China for examining local forest processes, structure and succession. A method of O-ring statistics （pair- correlation function） was applied to analyze the spatial patterns and associations of the dominant species within different vertical layers. After the evaluation by their importance values, six tree species （or group）（i.e. Abies nephrolepis, Picea jezoensis, Pinus koraiensis, Tilia amurensis, and species group of Betula ssp. and species group of Acer ssp.） were determined as dominant trees species. It was found that some of these species exhibited closely clustered distributions at fine distances. As spatial distance increased, a random or even regular distribution gradually appeared with the exception of the upper layers of A. nephrolepis and P. koraiensis, and the lower layers of P. jezoensis, P. koraiensis and Betula ssp., which were substantially randomly distributed. Intra- and inter-species spatial associations varied in accordance with species, tree height and reciprocal distances. Positive associations were observed between the lower and upper height classes of trees of the same species （except for that of P. jezoensis） at fine distances. This may be owing to limited seed dispersal and geological heterogeneity. The aggregation intensity declines with increasing distances and this consistent with the predictions of self-thinning. Some coniferous trees （e.g. Pinus koraiensis） in the lower height class were positively associated with T. amurensis and group of Betula ssp. of the upper height class at some distances, suggesting that saplings of coniferous trees occupy a broader niche and can grow well under the canopy of the adult of broad-leaved trees. Negative associations were observed between upper coniferous trees and lower broad-leaved trees and between upper P. jezoensis and lower P. koraiensis, suggesting that a canopy of thes

关键词： Mixed coniferous-broadleaf forest O-ring statistics Spatial pattern Spatial association Null model

Predicting the Reflection Coefficient of a Viscoelastic Coating Containing a Cylindrical Cavity Based on an Artificial Neural Network Model

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Computer Modeling in Engineering & Sciences 2022年第2期130卷 1149-1170页

作者： Yiping Sun Qiang Bai Xuefeng Zhao meng tao School of Mechanical Engineering Guizhou UniversityGuiyang550025China Aviation Academy Guizhou Open UniversityGuiyang550003China

A cavity viscoelastic structure has a good sound absorption performance and is often used as a reflective baffle or sound absorption cover in underwater acoustic *** acoustic performance field has become a key research direction *** of the time-consuming shortcomings of the traditional numerical analysis method and the high cost of the experimental method for measuring the reflection coefficient to evaluate the acoustic performance of coatings,this innovative study predicted the reflection coefficient of a viscoelastic coating containing a cylindrical cavity based on an artificial neural network(ANN).First,themapping relationship between the input characteristics and reflection coefficient was *** the elastic modulus and loss factor value were smaller,the characteristics of the reflection coefficient curve were more *** key parameters affected the acoustic performance of the viscoelastic ***,a dataset of the acoustic performance of the viscoelastic coating containing a cylindrical cavity was generated based on the finite elementmethod(FEM),which avoided a large number of repeated *** minmax normalization method was used to preprocess the input characteristics of the viscoelastic coating,and the reflection coefficient was used as the dataset *** grid search method was used to fine-tune the ANNparameters,and the prediction error was studied based on a 10-fold ***,the error distributions were *** average root means square error(RMSE)and the mean absolute percentage error(MAPE)predicted by the improved ANN model were 0.298%and 1.711%,respectively,and the Pearson correlation coefficient(PCC)was 0.995,indicating that the improved ANN model accurately predicted the acoustic performance of the viscoelastic coating containing a cylindrical *** practical engineering applications,by expanding the database of the material range,cavity size and backing of the coating

关键词： Coating acoustic performance artificial neural network predicting

Twin pregnancy with sudden heart failure and pulmonary hypertension after atrial septal defect repair: A case report

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World Journal of Clinical Cases 2023年第35期11卷 8350-8356页

作者： Chun-Xiao Tong tao meng Department of Obstetrical First Affiliated Hospital of China Medical UniversityShenyang 110000Liaoning ProvinceChina

BACKGROUND Pulmonary arterial hypertension(PAH)in pregnancy is one of the major obstetric complications and is considered a contraindication to pregnancy as it is classified as a class IV risk in the revised risk classification of pregnancy by the World Health ***,with its adaptive and expectant mechanical and hormonal changes,negatively affects the cardiopulmonary circulation in pregnant *** patients with repaired simple congenital heart disease(CHD)develop other pulmonary and cardiac complications during pregnancy?Can pregnant women with sudden pulmonary hypertension be treated and managed in time?In this paper,we present a case of a 39-year-old woman who underwent cesarean section at 33 wk'gestation and developed PAH secondary to repaired simple *** research began by a PubMed search for"pulmonary hypertension"and"pregnancy"and"CHD"case *** cases were selected to review PAH in pregnancy after correction of CHD *** studies were reviewed,coupled with our own clinical *** SUMMARY Herein,a case involving a woman who underwent atrial septal defect repair at the age of 34,became pregnant five years later,and had a sudden onset of PAH and right heart failure secondary to symptoms of acute peripheral edema in the third trimester of her *** a result,the patient underwent a cesarean section and gave birth to healthy *** three days after cesarean delivery,her cardiac function deteriorated as the pulmonary artery pressure ***-tive postpartum management,including diuresis,significant oxygen uptake,vasodilators,capacity and anticoagulants management,led to improvements in cardiac function and *** patient was discharged from hospital with a stable recovery and transferred to local hospitals for further PAH *** This case served as a reminder to obstetricians of the importance of pregnancy after repair of *** is crucial for patients with CHD to receive early co

关键词： Congenital heart defects Pulmonary hypertension Right heart failure Twin pregnancy Perioperative management Case report