检索结果-南通市图书馆

Chinese Journal of Chemical Engineering 2024年第3期67卷 157-165页

作者： Shunda lin Yang Lu Lin Zheng Ling Long Xuguang Jiang Jianhua Yan State Key Laboratory of Clean Energy Utilization Institute for Thermal Power EngineeringZhejiang UniversityHangzhou 310027China Zhejiang University Qingshanhu Energy Research Center Hangzhou 310027China hangzhou Xiaoshan Jinjiang Green Energy Co. Ltd.XiaoshanHangzhou 310000China

High concentrations of copper ions(Cu(Ⅱ)) in water will pose health risks to humans and the ecological environment. Therefore, this study aims to utilize ultrasonic-cured modified municipal solid waste incineration(MSWI) fly ash for Cu(Ⅱ) adsorption to achieve the purpose of “treating waste by waste.” The effects of p H, adsorption time, initial concentration, and temperature on the modified MSWI fly ash’s adsorption efficiency were systematically studied in this article. The adsorption performance of the modified MSWI fly ash can be enhanced by the ultrasonic modification. At pH = 2, 3 and 4, the adsorption capacity of the modified MSWI fly ash for Cu(Ⅱ) increased by 2.7, 1.9 and 1.2 times, respectively. Furthermore, it was suggested that the adsorption process of the modified MSWI fly ash can be better simulated by the pseudo-second-order kinetic model, with a maximum adsorption capacity calculated by the Langmuir model of 24.196 mg.g-1. Additionally, the adsorption process is spontaneous,endothermic, and chemisorption-dominated from the thermodynamic studies(ΔH and ΔS > 0, ΔG < 0).Finally, the enhanced adsorption performance of the modified MSWI fly ash for Cu(Ⅱ) may be attributed to electrostatic interaction and chelation effects.

关键词： Ultrasound MSWI fly ash Cu(Ⅱ) Wastewater Adsorption

Compressed Data Separation viaℓ_(q)-Split Analysis withℓ_(∞)-Constraint

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2024年第7期40卷 1655-1673页

作者： Ming Yang Gu Song Li Jun Hong Lin School of Mathematical Science Zhejiang UniversityHangzhou310027P.R.China Center for Data Science Zhejiang UniversityHangzhou310027P.R.China

In this paper,we study compressed data separation(CDS)problem,i.e.,sparse data separation from a few linear random measurements.We propose the nonconvexℓ_(q)-split analysis withℓ_(∞)-constraint and 0 详细信息

关键词： Data separation ℓ_(q)-split analysis Dantzig selector frames restricted isometry property compressed sensing

Promoting effect of FeOx addition on the mechanochemically prepared vanadium-based catalyst for real PCDD/Fs removal and mechanism insight

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第3期137卷 478-487页

作者： Minghui Tang Ling Wang Hongxian Li Xinlei Huang Cuicui Du Shengyong Lu State Key Laboratory for Clean Energy Utilization Institute for Thermal Power EngineeringZhejiang UniversityHangzhou 310027China

Industrial-use VOx-based catalysts usually have a higher active temperature window (>250-300℃),which becomes a“bottleneck”for the practical application of PCDD/Fs catalytic degradation technology.In this work,VO_(x)-FeO_(x)/TiO_(2) catalyst prepared via mechanochemically method was investigated for the catalytic removal of PCDD/Fs.The removal efficiency of 1,2-DCBz,pure PCDD/Fs gas generated in the lab,PCDD/Fs from actual fue gas,long-term were studied,and the degradation mechanism was explored using FTIR and TOFMS.The degradation efficiency of 1,2-DCBz and PCDD/Fs on VO_(x)-FeO_(x)/TiO_(2) were higher than that of VO_(x)/TiO_(2)catalyst,and the optimal FeOx addition ratio was 3 wt.%.The characterization results show that the addition of FeOx can effectively improve the pore structure,surface acidity,and VOx dispersion of the catalyst,thus contributing to increasing the V^(5+)content and surface-active oxygen,which is conducive to the improvement of adsorption and redox performance of the catalyst.Under the actual MSWI (municipal solid waste incineration)fue gas,the PCDD/Fs removal efficiency over VTi-3Fe-MC maintained long-term stability,higher than 85%for 240 min.This result was not significantly reduced compared with the data obtained in the laboratory.According to the analysis results of intermediate products by FTIR and GC-TOFMS,it can be inferred that the epoxidation fracture of benzene ring is the rate-limiting step of dioxin catalytic degradation reaction.This work gives an in-depth view into the PCDD/Fs removal over VO_(x)-FeO_(x)/TiO_(2) catalysts and could provide guidelines for the rational design of reliable catalysts for industrial applications.

关键词： PCDD/F removal MSWI fue gas VO_(x)-FeO_(x)/TiO_(2) Mechanochemical GC-TOFMS

Improvement for creep strength of a second-generation single crystal superalloy by design of heat treatments

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第1期43卷 342-350页

作者： Wan-Shun Xia Xin-Bao Zhao Jia-Chen Xu Quan-Zhao Yue Qing-Qing Ding Huan-Chang Duan Yue-Feng Gu Hong-Bin Bei Ze Zhang Institute of Superalloys Science and Technology School of Materials Science and EngineeringZhejiang UniversityHangzhou 310027China State Key Laboratory of Silicon and Advanced Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou 310027China

Design of heat treatments is related to the key technology for development of nickel-based single crystal superalloys(Ni-SXs). Based on the full understanding of the solidification characteristics, this work applies optimization design of heat treatments for a second-generation Ni-SX. Microstructure evolution and creep properties are compared in the material under conventional/standard(Std.) and optimized(Opt.) treatments. For the Std. sample,strong dendritic segregations determine inconsistent microstructure evolution in the dendritic(D) and interdendritic region(ID), while the latter serves as weak area to have the prior microcrack initiation, damaging overall performance of the alloy. The Opt. treatment applies higher homogenization temperature, leading to overall reduced segregations, while not inducing incipient melting. A lower temperature of first-step ageing is used to lower the size ofγ'particles. These help to form the more uniform microstructure in dendritic and interdendritic region and relieve the inconsistent microstructure evolution. The balanced local strength makes ID no longer as the weak area,thus restricting microcrack initiation. Great improvement of high temperature and low stress property is obtained by this progress, leading to the pronounced increase of creep rupture life under 1100 °C/140 MPa.

关键词： Single crystal superalloy Heat treatment Segregation Solidification Creep property

NFXL1 functions as a transcriptional activator required for thermotolerance at reproductive stage in Arabidopsis

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2024年第1期66卷 54-65页

作者： Qiao‐Yun Zhu Lin‐Lin Zhang Jian‐Xiang Liu State Key Laboratory of Plant Environmental Resilience College of Life SciencesZhejiang UniversityHangzhou 310027China

Plants are highly susceptible to abiotic stresses,particularly heat stress during the reproductive stage.However,the specific molecular mechanisms underlying this sensitivity remain largely unknown.In the current study,we demonstrate that the Nuclear Transcription Factor,X-box Binding Protein 1-Like 1(NFXL1),directly regulates the expression of DEHYDRATION-RESPONSIVE ELEMENT-BINDING PROTEIN 2A(DREB2A),which is crucial for reproductive thermotolerance in Arabidopsis.NFXL1 is upregulated by heat stress,and its mutation leads to a reduction in silique length(seed number)under heat stress conditions.RNA-Seq analysis reveals that NFXL1 has a global impact on the expression of heat stress responsive genes,including DREB2A,Heat Shock Factor A3(HSFA3)and Heat Shock Protein 17.6(HSP17.6)in flower buds.Interestingly,NFXL1 is enriched in the promoter region of DREB2A,but not of either HSFA3 or HSP17.6.Further experiments using electrophoretic mobility shift assay have confirmed that NFXL1 directly binds to the DNA fragment derived from the DREB2A promoter.Moreover,effector-reporter assays have shown that NFXL1 activates the DREB2A promoter.The DREB2A mutants are also heat stress sensitive at the reproductive stage,and DEREB2A is epistatic to NFXL1 in regulating thermotolerance in flower buds.It is known that HSFA3,a direct target of DREB2A,regulates the expression of heat shock proteins genes under heat stress conditions.Thus,our findings establish NFXL1 as a critical upstream regulator of DREB2A in the transcriptional cassette responsible for heat stress responses required for reproductive thermotolerance in Arabidopsis.

关键词： Arabidopsis DREB2A heat stress NFXL1 reproductive thermotolerance

Towards understanding bogus traffic service in online social networks

在线全文

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2024年第3期25卷 415-431页

作者： Ping HE Xuhong ZHANG Changting LIN Ting WANG Shouling JI College of Computer Science and Technology Zhejiang UniversityHangzhou 310027China Binjiang Institute of Zhejiang University Hangzhou 310027China College of Information Sciences and Technology Pennsylvania State UniversityUniversity Park 17057-4846USA

Critical functionality and huge infuence of the hot trend/topic page(HTP)in microblogging sites have driven the creation of a new kind of underground service called the bogus traffic service(BTS).BTS provides a kind of illegal service which hijacks the HTP by pushing the controlled topics into it for malicious customers with the goal of guiding public opinions.To hijack HTP,the agents of BTS maintain an army of black-market accounts called bogus trafic accounts(BTAs)and control BTAs to generate a burst of fake trafic by massively retweeting the tweets containing the customer desired topic(hashtag).Although this service has been extensively exploited by malicious customers,little has been done to understand it.In this paper,we conduct a systematic measurement study of the BTS.We first investigate and collect 125 BTS agents from a variety of sources and set up a honey pot account to capture BTAs from these agents.We then build a BTA detector that detects 162218 BTAs from Weibo,the largest Chinese microblogging site,with a precision of 94.5%.We further use them as a bridge to uncover 296916 topics that might be involved in bogus trafic.Finally,we uncover the operating mechanism from the perspectives of the attack cycle and the attack entity.The highlights of our findings include the temporal attack patterns and intelligent evasion tactics of the BTAs.These findings bring BTS into the spotlight.Our work will help in understanding and ultimately eliminating this threat.

关键词： Online social networks Measurement Bogus traffic Black market

A learning-based control pipeline for generic motor skills for quadruped robots

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第6期25卷 443-454页

作者： Yecheng SHAO Yongbin JIN Zhilong HUANG Hongtao WANG Wei YANG Center for X-Mechanics Zhejiang UniversityHangzhou310027China ZJU-hangzhou Global Scientific and Technological Innovation Center Hangzhou311200China State Key Laboratory of Fluid Power&Mechatronic Systems Zhejiang UniversityHangzhou310058China Institute of Applied Mechanics Zhejiang UniversityHangzhou310027China

Performing diverse motor skills with a universal controller has been a longstanding challenge for legged robots.While motion imitation-based reinforcement learning(RL)has shown remarkable performance in reproducing designed motor skills,the trained controller is only suitable for one specific type of motion.Motion synthesis has been well developed to generate a variety of different motions for character animation,but those motions only contain kinematic information and cannot be used for control.In this study,we introduce a control pipeline combining motion synthesis and motion imitation-based RL for generic motor skills.We design an animation state machine to synthesize motion from various sources and feed the generated kinematic reference trajectory to the RL controller as part of the input.With the proposed method,we show that a single policy is able to learn various motor skills simultaneously.Further,we notice the ability of the policy to uncover the correlations lurking behind the reference motions to improve control performance.We analyze this ability based on the predictability of the reference trajectory and use the quantified measurements to optimize the design of the controller.To demonstrate the effectiveness of our method,we deploy the trained policy on hardware and,with a single control policy,the quadruped robot can perform various learned skills,including automatic gait transitions,high kick,and forward jump.

关键词： Quadruped robot Reinforcement learning(RL) Motion synthesis Control

In Situ Analysis of Tobacco Leaves Based on Microwave Plasma Torch Desorption Ionization Mass Spectrometry

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Analysis and Testing 2024年第1期8卷 9-15页

作者： He Tang Yonggang Zhang Zhiguang Reng Junchen Zhu Yue Xie Xiaobin Zhang Hongru Feng Kailong Yuan Yuanjiang Pan Department of Chemistry Zhejiang UniversityHangzhou 310027China Zhejiang China Tobacco Industrial Co. Ltd.Hangzhou310008China

Tobacco is an important economic crop worldwide.Tobacco leaves contain a large number of natural products.Therefore,the analysis of tobacco composition is crucial for the control of tobacco safety and quality assessment.Microwave plasma torch desorption ionization mass spectrometry(MPT-MS) is an emerging ambient mass spectrometry(AMS) technique that can be used for rapid real-time analysis of s amples without pretreatment.Our work focuses on the chemical composition analysis of tobacco using MPT-MS,and 14 compounds were detected in green flue-cured tobacco leaves,while 30 compounds were detected in cured flue-cured tobacco leaves,which confirms that curing can enhance the flavor of cigarettes.Furthermore,we successfully in situ identified characteristic fragment ions of α/β-CBD(α/β-cembranoids),an important aroma compound in tobacco by MPT-MS.The results demonstrate the capability of MPT-MS for in situ analysis of tobacco components and its potential for evaluating tobacco quality.

关键词： Microwave plasma torch Ambient mass spectrometry Tobacco α/β-Cembranoids

Combining reinforcement learning with mathematical programming:An approach for optimal design of heat exchanger networks

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2024年第5期69卷 63-71页

作者： Hui Tan Xiaodong Hong Zuwei Liao Jingyuan Sun Yao Yang Jingdai Wang Yongrong Yang State Key Laboratory of Chemical Engineering College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310027China ZJU-hangzhou Global Scientific and Technological Innovation Center Hangzhou 311215China

Heat integration is important for energy-saving in the process industry.It is linked to the persistently challenging task of optimal design of heat exchanger networks(HEN).Due to the inherent highly nonconvex nonlinear and combinatorial nature of the HEN problem,it is not easy to find solutions of high quality for large-scale problems.The reinforcement learning(RL)method,which learns strategies through ongoing exploration and exploitation,reveals advantages in such area.However,due to the complexity of the HEN design problem,the RL method for HEN should be dedicated and designed.A hybrid strategy combining RL with mathematical programming is proposed to take better advantage of both methods.An insightful state representation of the HEN structure as well as a customized reward function is introduced.A Q-learning algorithm is applied to update the HEN structure using theε-greedy strategy.Better results are obtained from three literature cases of different scales.

关键词： Heat exchanger network Reinforcement learning Mathematical programming Process design

GLOBAL EXISTENCE AND ASYMPTOTICS BEHAVIOR OF SOLUTIONS FOR A RESONANT KLEIN-GORDON SYSTEM IN TWO SPACE DIMENSIONS

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2005年第1期26卷 89-104页

作者： XUERUYING FANGDAOYUAN DepartmentofMathematics ZhejiangUniversityHangzhou310027China DepartmentofMathematics ZhejiangUniversityHangzhou310027China

The authors study a resonant Klein-Gordon system with convenient nonlinearities in two space dimensions, prove that such a system has global solutions for small, smooth,compactly supported Cauchy data, and find that t... 详细信息

关键词：克莱恩-戈登方程渐近性全局存在性非线性偏微分方程