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Electrosynthesis and catalytic properties of silver nano/microparticles with different morphologies

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Particuology 2011年第6期9卷 644-649页

作者： Gaoqing yuan Xiaoying Chang Guojun zhu School of Chemistry and Chemical Engineering South China University of Technology Guangzhou 510640 Guangdong China

Electrosynthesis of powdery silver particles can be effectively carried out with an H20-oleic acid or an H20-glycerol mix solvent （volume ratio 1：1） as the electrolytic medium and AgN03 as the supporting electrolyte. Experimental results indicate that the presence or absence of the surfactant sodium dodecyl sulfate （SDS） and the choice of electrolytic medium have a significant impact on the shape and size of the prepared Ag particles. With H20-glycerol as the electrolytic medium, spherical Ag nanoparticles can be obtained in the presence of SDS （0.6g/L）, while an Ag sample electrodeposited without SDS has a dendritic microcrystalline structure. For the reduction of methyl orange （MO） and methylene blue （MB） with NaBH4 as the reducing agent, the spherical Ag nanoparticles exhibit much better catalytic activity than the dendritic Ag microparticles. Further investigations show that surface modification by an oleic acid medium could greatly improve the catalytic activity of the electrodeposited Ag particles for the reduction of MO and MB.

关键词： Electrosynthesis Silver Nanoparticles Surface modification Oleic acid

Grain boundary segregation of minor arsenic and nitrogen at elevated temperatures in a microalloyed steel

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International Journal of Minerals,Metallurgy and Materials 2012年第5期19卷 399-403页

作者： yuan-zhi zhu Zhe zhu Jian-ping Xu The Key Laboratory of the Ministry of Education of China for Ferrous Metallurgy and Resources Utilization Wulaan University of Science and Technology Wuhan430081 China School of Materials and Metallurgy Wuhan University of Science and Technology Wuhan 430081 China

Auger electron spectroscopy （AES） was used to investigate the grain boundary segregation of arsenic and nitrogen in a kind of microalloyed steel produced by a compact strip production （CSP） technology at 950 to 1100℃, which are similar to the hot working temperature of the steel on a CSP production line. It was discovered that arsenic segregated on grain boundaries when the steel was annealed at 950℃ for 2 h. When the annealing temperature increased to 1100℃, arsenic was also found to have segregated on grain boundaries in the early annealing stage, for instance, within the first 5 min annealing time. However, if the holding time of the steel at this temperature increased to 2 h, arsenic diffused away from grain boundaries into the matrix again. Nitrogen was not found to have segregated on grain boundaries when the steel was annealed at a relatively low temperature, such as 950℃. But when the annealing temperature increased to 1100℃, nitrogen was detected to have segregated at grain boundaries in the steel.

关键词： alloy steel arsenic nitrogen segregation grain boundaries

Gradient microstructure and superior strength-ductility synergy of AZ61 magnesium alloy bars processed by radial forging with different deformation temperatures

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Journal of Materials Science & Technology 2024年第3期170卷 65-77页

作者： Jingfeng Zou Lifeng Ma Yanchun zhu Ling Qin yuan yuan School of Mechanical Engineering Taiyuan University of Science and TechnologyTaiyuan 030024China Heavy Machinery Engineering Research Center of the Ministry Education Taiyuan University of Science and TechnologyTaiyuan 030024China Department of Engineering University of HullCottingham RdHull HU67RXUK National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China

Gradient microstructure modification is a cost-efficient strategy for high strength without compromising ductility,which is urgently needed in the fundamental science of engineering *** this study,heterogeneous structures of AZ61 alloy bars with anisotropic gradients(with different grain size distributions from the surface to the center)were observed to exhibit strong strength-ductility synergies under different deformation tem *** results reveal that the grain refinement process under mediumlow temperature deformation conditions(≤350℃)consists of four transition stages along the radial direction,i.e.,twin activations and deformation band formations,dislocation cells and pile-ups,ultrafine sub-grains,and randomly orientated quasi-micron *** deformation temperatures have a great influence on twin activations and deformation band formations,and the high temperature can easily provoke the initiation of non-basal *** deformation bands were determined as a primary nucleation site due to their highly unstable dislocation hindrance *** in combination with the Radial forging(RF)deformation process,the differences of dynamic precipitates can be attributed to microstructural difference and solubility limit of Al at different tem *** summarizing the tensile test results,the sample forged at 350℃exhibited the best strength-ductility synergy,exhibiting the highest elongation(EL)of 23.2%with a 251 MPa yield strength(YS)and 394 MPa ultimate tensile strength(UTS)in center region,and combined with the highest strength value of 256 MPa YS and 420 MPa UTS in the center region,while the EL was slightly degraded to 19.8%.

关键词： Gradient microstructure Radial forging Strength-ductility synergy Magnesium alloy Strengthening mechanism

A method to study interface diffusion of arsenic into a Nb-Ti microalloyed low carbon steel

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International Journal of Minerals,Metallurgy and Materials 2012年第9期19卷 821-826页

作者： yuan-zhi zhu Jian-ping XU The Key Laboratory of the Ministry of Education of China for Ferrous Metallurgy and Resources Utilization Wuhan University of Science and Technology Wuhan 430081 China School of Materials and Metallurgy Wuhan University of Science and Technology Wuhan 430081 China

A novel diffusion couple method was used to investigate the interface diffusion of arsenic into a Nb-Ti microalloyed low carbon steel and its effects on phase transformation at the interface. It is discovered that the content of arsenic has great effect on grain growth and phase transformation at high temperature. When the arsenic content is no more than lwt%, there is no obvious grain growth and no obvious ferrite transitional region formed at the diffusion interface. However, when the arsenic content is no less than 5wt%, the grain grows very rapidly. In addition, the arsenic-enriched ferrite transitional layer forms at the diffusion interface in the hot-rolling process, which results from a slower diffusion rate of arsenic atoms than that of carbon in ferrite.

关键词： low carbon steel alloy steel arsenic diffusion bonding phase transformation grain growth

Multivariate time delay analysis based local KPCA fault prognosis approach for nonlinear processes

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Chinese Journal of Chemical Engineering 2016年第10期24卷 1413-1422页

作者： yuan Xu Ying Liu Qunxiong zhu College of Information Science and Technology Beijing University of Chemical Technology

Currently, some fault prognosis technology occasionally has relatively unsatisfied performance especially for in- cipient faults in nonlinear processes duo to their large time delay and complex internal connection. To overcome this deficiency, multivariate time delay analysis is incorporated into the high sensitive local kernel principal component analysis. In this approach, mutual information estimation and Bayesian information criterion （BIC） are separately used to acquire the correlation degree and time delay of the process variables. Moreover, in order to achieve prediction, time series prediction by back propagation （BP） network is applied whose input is multivar- iate correlated time series other than the original time series. Then the multivariate time delayed series and future values obtained by time series prediction are combined to construct the input of local kernel principal component analysis （LKPCA） model for incipient fault prognosis. The new method has been exemplified in a sim- ple nonlinear process and the complicated Tennessee Eastman （TE） benchmark process. The results indicate that the new method has suoerioritv in the fault prognosis sensitivity over other traditional fault prognosis methods.

关键词： Fault prognosis Time delay estimation Local kernel principal component analysis

Effects of mechanized deep placement of nitrogen fertilizer rate and type on rice yield and nitrogen use efficiency in Chuanxi Plain, China

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Journal of Integrative Agriculture 2021年第2期20卷 581-592页

作者： zhu Cong-hua OUYANG Yu-yuan DIAO you YU Jun-qi LUO Xi ZHENG Jia-guo LI Xu-yi Crop Research Institute Sichuan Academy of Agricultural SciencesChengdu 610066P.R.China Sichuan Province Key Laboratory of Crop Ecophysiology and Cultivation Chengdu 611130P.R.China

This paper investigates the yield and nitrogen use efficiency (NUE) of machine-transplanted rice cultivated using mechanized deep placement of N fertilizer in the rice–wheat rotation region of Chuanxi Plain,*** provides theoretical support for N-saving and improves quality and production efficiency of machine-transplanted *** a single-factor complete randomized block design in field experiments in 2018 and 2019,seven N-fertilization treatments were applied,with the fertilizer being surface broadcast and/or mechanically placed beside the seedlings at (5.5±0.5) cm soil depth when *** treatments were:N0,no N fertilizer;U1,180 kg N ha^(–1) as urea,surface broadcast manually before transplanting;U2,108 kg N ha^(–1) as urea,surface broadcast manually before transplanting,and 72 kg N ha^(–1) as urea surface broadcast manually on the 10th d after transplanting,which is not only the local common fertilization method,but also the reference treatment;UD,180 kg N ha^(–1) as urea,mechanically deep-placed when transplanting;M1,81.6 kg N ha^(–1) as urea and 38.4 kg N ha^(–1) as controlled-release urea (CRU),mechanically deep-placed when transplanting;M2,102 kg N ha^(–1) as urea and48 kg N ha^(–1) as CRU,mechanically deep-placed when transplanting;M3,122.4 kg N ha^(–1) as urea and 57.6 kg N ha^(–1) as CRU,mechanically deep-placed when *** effects of the N fertilizer treatments on rice yield and NUE were consistent in the 2 *** a N application rate of 180 kg ha^(–1),compared with U2,the N recovery efficiency (NRE),N agronomic use efficiency (NAE) and yield under the UD treatment were 20.6,3.5 and 1.1% higher in 2018,and 4.6,1.7 and 1.2% higher in 2019,*** with urea alone (U1,U2 or UD),the NRE,NAE and yield achieved by M3 (combined application of urea and controlled-release urea) were higher by 9.2–73.3%,18.6–61.5% and 6.5–16.5%(2018),and 22.2–65.2%,25.6–75.0% and 5.9–13.9%(2019),*** with M3,the lower-N t

关键词： rice N-fertilization rate controlled release urea side deep fertilization yield nitrogen use efficiency

Spatiotemporal estimation of hourly 2-km ground-level ozone over China based on Himawari-8 using a self-adaptive geospatially local model

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Geoscience Frontiers 2022年第1期13卷 204-216页

作者： yuan Wang Qiangqiang yuan Liye zhu Liangpei Zhang School of Geodesy and Geomatics Wuhan UniversityWuhanHubei 430079China School of Atmospheric Science Sun Yat-sen UniversityGuangzhouGuangdong 510275China The Key Laboratory of Geospace Environment and Geodesy Ministry of EducationWuhan UniversityWuhanHubei 430079China The State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhanHubei 430079China

Ground-level ozone(O_(3))is a primary air pollutant,which can greatly harm human health and *** present,data fusion frameworks only provided ground-level O_(3) concentrations at coarse spatial(e.g.,10 km)or temporal(e.g.,daily)*** photochemical pollution continues increasing over China in the last few years,a high-spatial–temporal-resolution product is required to enhance the comprehension of ground-level O_(3) formation *** address this issue,our study creatively explores a brand-new framework for estimating hourly 2-km ground-level O_(3) concentrations across China(except Xinjiang and Tibet)using the brightness temperature at multiple thermal infrared *** the spatial heterogeneity of ground-level O_(3),a novel Self-adaptive Geospatially Local scheme based on Categorical boosting(SGLboost)is developed to train the estimation *** results show that SGLboost performs well in the study area,with the R2 s/RMSEs of 0.85/19.041 lg/m^(3) and 0.72/25.112 lg/m^(3) for the space-based cross-validation(CV)(2017–2019)and historical space-based CV(2019),***,SGLboost achieves distinctly better metrics than those of some widely used machine learning methods,such as e Xtreme Gradient boosting and Random *** to recent related works over China,the performance of SGLboost is also more *** the spatial distribution,the estimated results present continuous spatial patterns without a significantly partitioned boundary *** addition,accurate hourly and seasonal variations of ground-level O_(3) concentrations can be observed in the estimated results over the study *** is believed that the hourly 2-km results estimated by SGLboost will help further understand the formation mechanisms of ground-level O_(3) in China.

关键词： Spatiotemporal estimation Air pollution Ground-level O_(3) SGLboost China

Method for detector description transformation to Unity and application in BESⅢ

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Nuclear Science and Techniques 2022年第11期33卷 79-88页

作者： Kai-Xuan Huang Zhi-Jun Li Zhen Qian Jiang zhu Hao-yuan Li Yu-Mei Zhang Sheng-Sen Sun Zheng-Yun you School of Physics Sun Yat-sen UniversityGuangzhou 510275China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China

Detector and event visualization are essential parts of the software used in high-energy physics(HEP)*** visualization techniques and multimedia production platforms such as Unity provide impressive display effects and professional extensions for visualization in HEP *** this study,a method for automatic detector description transformation is presented,which can convert the complicated HEP detector geometry from GDML in offline software to 3D modeling in *** method was successfully applied in the BESIII experiment and can be further developed into applications such as event displays,data monitoring,or virtual *** has great potential in detector design,offline software development,physics analysis,and outreach for next-generation HEP experiments as well as applications in nuclear techniques for the industry.

关键词： Detector description Visualization Unity GDML BESIII

Multilinear Calderón-Zygmund Operators and Their Commutators with BMO Functions in Herz-Morrey Spaces with Variable Smoothness and Integrability

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Communications in Mathematical Research 2017年第3期33卷 238-258页

作者： hu yuan-zhu xu jing-shi ji you-qing School of Mathematics and Statistics Hainan Normal University Haikou 571158 不详

In this paper, we obtain that multilinear Calderón-Zygmund operators and their commutators with BMO functions are bounded on products of Herz-Morrey spaces with variable smoothness and integrability. The vector-value... 详细信息

关键词： multilinear Calderón-Zygmund operator variable exponent Herz-Morrey space vector valued estimate