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Chinese Chemical Letters 2015年第2期26卷 187-192页

作者： Hao Wang Yi-Ping Chen zhu-chai you Meng-Xi Zhou Ning Zhang Yan-Qiong Sun College of Chemistry Fuzhou University State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of Sciences

A Keggin-type polyoxomolybdate[H2biim]{Ni（biim）3（SiMO12O40）}[biim =1H,1＇H-[2,2＇]biimidazolyl]has been synthesized under hydrothermal condition and characterized by XRD,temperature-dependent IR,TG,temperature-induced and magnetism-induced 2D infrared correlation spectroscopy（2D-IR COS）and UV-vis DRS in order to explore the relationship between structure and *** 2D-IR COS spectroscopy indicates that the terminal Mo-Oμ/υbonds are more sensitive than the bridging Mo=Ot,bands to temperature variation,which is in agreement with the conclusion of temperature-dependent ***-dependent 2D-IR COS spectroscopy reveals the stretching vibration of the Mo=Ot,occurs prior to the stretching vibration of the Mo-Oμ/υ,which is due to the coordination environment and the valence of the Si *** stability of compound 1 is investigated via TG and temperature-dependent *** RhB degradation,compound 1 shows good photocatalytic abilities.

关键词： 2D infrared correlation spectroscopy Photocatalytic degradation of RhB Silicon molybdenum polyoxometalate

Combo Packet:An Encryption Traffic Classification Method Based on Contextual Information

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Computers, Materials & Continua 2024年第4期79卷 1223-1243页

作者： Yuancong chai Yuefei zhu Wei Lin Ding Li State Key Laboratory of Mathematical Engineering and Advanced Computing Information Engineering UniversityZhengzhou450001China

With the increasing proportion of encrypted traffic in cyberspace, the classification of encrypted traffic has becomea core key technology in network supervision. In recent years, many different solutions have emerged in this *** methods identify and classify traffic by extracting spatiotemporal characteristics of data flows or byte-levelfeatures of packets. However, due to changes in data transmission mediums, such as fiber optics and satellites,temporal features can exhibit significant variations due to changes in communication links and transmissionquality. Additionally, partial spatial features can change due to reasons like data reordering and *** with these challenges, identifying encrypted traffic solely based on packet byte-level features is significantlydifficult. To address this, we propose a universal packet-level encrypted traffic identification method, ComboPacket. This method utilizes convolutional neural networks to extract deep features of the current packet andits contextual information and employs spatial and channel attention mechanisms to select and locate effectivefeatures. Experimental data shows that Combo Packet can effectively distinguish between encrypted traffic servicecategories (e.g., File Transfer Protocol, FTP, and Peer-to-Peer, P2P) and encrypted traffic application categories (e.g.,BitTorrent and Skype). Validated on the ISCX VPN-non VPN dataset, it achieves classification accuracies of 97.0%and 97.1% for service and application categories, respectively. It also provides shorter training times and higherrecognition speeds. The performance and recognition capabilities of Combo Packet are significantly superior tothe existing classification methods mentioned.

关键词： Encrypted traffic classification packet-level convolutional neural network attention mechanisms

Characterizing extreme drought and wetness in Guangdong,China using global navigation satellite system and precipitation data

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Satellite Navigation 2024年第1期5卷 258-274页

作者： Hai zhu Kejie Chen Haishan chai Yuanbin Ye Wenjian Liu Department of Earth and Space Sciences Southern University of Science and TechnologyShenzhen518055China Lands and Resource Department of Guangdong Province Surveying and Mapping InstituteGuangzhou510500China

As global temperature rises,the frequency of extreme climate events,e.g.,severe droughts and floods,has increased significantly and caused severe damage over the past *** this regard,precipitation efficiency,a crucial meteorological parameter,could provide valuable insights for a better understanding of the patterns and characteristics of these extreme *** this study,taking Guangdong province as an exemplary region,we first obtained long-term and high-resolution historical records of precipitation efficiency by integrating the observations from a dense network of Global Navigation Satellite System(GNSS)stations with precipitation data,and then characterized the extreme drought and wetness through climate *** found a distinct seasonal trend in precipitation efficiency in Guangdong,with annual fluctuations ranging from 10 to 25%.Notably,precipitation efficiency is higher in proximity to the Pearl River Delta Plain and gradually decreases towards the east and *** occurrence of anomalous peaks and valleys in precipitation efficiency generally corresponds to dry and wet conditions,respectively.A total of 9 extreme wet events and 6 dry events occurred from January 2007 to May 2022,with durations from 3 to 6 *** results also demonstrated that both wet and dry frequencies exhibit an increasing trend with the expansion of the time scale,and the frequency of extreme events near the Pearl River Delta Plain surpasses that of other ***,the propagation time from meteorological anomalies to agricultural and hydrological anomalies is about 3 *** periodic characteristics of meteorological anomalies are identified as the primary driver for other anomalous periodic *** work unveils the long-term dynamic behavior of precipitation efficiency,as well as the characteristics of extreme drought and wetness events in the regions characterized by intricate land–atmosphere interactions.

关键词： GNSS Precipitation efficiency Extreme drought and wetness

Highly dispersed MgInCe-mixed metal oxides catalyzed direct carbonylation of glycerol and CO_(2)into glycerol carbonate

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Chinese Journal of Chemical Engineering 2024年第8期72卷 153-163页

作者： Xufang Chen Xin Shu Yanru zhu Jian Zhang Zhigang chai Hongyan Song Zhe An Jing He State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China Quzhou Institute for Innovation in Resource Chemical Engineering Quzhou 324000China

Glycerol carbonate,an important glycerol value-added product,has been widely used as an active intermediate and inert solvent in the synthesis of cosmetics,detergents,chemical intermediates,polymers,and so *** direct carbonylation from glycerol with CO_(2)is considered a promising route,but still tough work due to the thermodynamic stability and the kinetic inertness of CO_(2).In this work,highlyselective direct carbonylation of glycerol and CO_(2)into glycerol carbonate has been achieved over highly dispersed MgInCe-mixed metal oxides(MgInCe-MMO),which were prepared through the topological transformation derived from the MgInCe-layered double hydroxides(MgInCe-LDHs).By precisely modulating the surface basic-acidic properties and the oxygen vacancies,an efficient carbonylation of glycerol with CO_(2)has been achieved with a selectivity of up to>99%to glycerol *** investigation into the synergistic catalysis of base-acid sites and oxygen vacancies has been clarified.

关键词： Catalytic reaction engineering Glycerol carbonate Direct carbonylation from glycerol Carbon dioxide Mixed metal oxides Synergistic catalysis

A novel matrix topology-based analysis method of thermal circuits for reliability optimization of HSER

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Chinese Journal of Aeronautics 2024年第4期37卷 479-492页

作者： Huimin LIANG Bo LI Jiaxin you Shan JIANG Mengtong zhu Aobo WANG Department of Electrical Engineering Harbin Institute of TechnologyHarbin 150001China Nanjing Research Institute of Electronics Technology Nanjing 210008China

Hermetically Sealed Electromagnetic Relay(HSER), used in aviation and aerospace,demands high reliability due to its critical applications. Given its complex operating conditions, efficient thermal analysis is essential for optimizing reliability. The commonly used Finite Element Method(FEM) is often time-consuming and may not be efficient or adaptable for complex multi-dimensional system calculations and design processes. This paper introduces an analysis method for thermal networks based on matrix perspective technology, encompassing matrix transformation, backpropagation of the heat path model, temperature rise calculation, solution comparison, and product implementation. Using the similarity theory of heat circuits, a basic thermal unit is established. Based on the fundamental connection between key components, a thermal network for a typical HSER is designed. An experimental system is set up, and the thermal network model's accuracy is confirmed using test data. Employing the topology analysis method, the topology of the thermal network is analyzed under both coil-energized and de-energized states. Potential thermal paths are identified, leading to optimized solutions for the HSER. Utilizing these solutions, the thermal path matrix topology model is backpropagated to the thermal path for temperature rise calculations. When compared to prototype HSER test data, the efficiency and accuracy of this matrix topology-based analysis method are confirmed.

关键词： Thermal networks HSER(Hermetically Sealed Electromagnetic Relay) Heat-circuit topology model Heat-circuit matrix Optimization design

Understanding adversarial attacks on observations in deep reinforcement learning

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Science China(Information Sciences) 2024年第5期67卷 69-83页

作者： you QIAOBEN Chengyang YING Xinning ZHOU Hang SU Jun zhu Bo ZHANG Department of Computer Science and Technology Beijing National Research Center for Information Science and Technology Tsinghua-Bosch Joint Center for Machine Learning Institute for Artificial Intelligence Tsinghua University Peng Cheng Laboratory

Deep reinforcement learning models are vulnerable to adversarial attacks that can decrease the cumulative expected reward of a victim by manipulating its observations. Despite the efficiency of previous optimization-based methods for generating adversarial noise in supervised learning, such methods might not achieve the lowest cumulative reward since they do not generally explore the environmental ***, a framework is provided to better understand the existing methods by reformulating the problem of adversarial attacks on reinforcement learning in the function space. The reformulation approach adopted herein generates an optimal adversary in the function space of targeted attacks, repelling them via a generic two-stage framework. In the first stage, a deceptive policy is trained by hacking the environment and discovering a set of trajectories routing to the lowest reward or the worst-case performance. Next, the adversary misleads the victim to imitate the deceptive policy by perturbing the observations. Compared to existing approaches, it is theoretically shown that our adversary is strong under an appropriate noise level. Extensive experiments demonstrate the superiority of the proposed method in terms of efficiency and effectiveness, achieving state-of-the-art performance in both Atari and MuJoCo environments.

关键词： deep learning reinforcement learning adversarial robustness adversarial attack

Unraveling the role of formate in improving nitrogen removal via coupled partial denitrification-anammox

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Frontiers of Environmental Science & Engineering 2024年第9期18卷 79-90页

作者： Wanlu zhu Rui Xiao Min Xu Wenbo chai Wenlong Liu Zhengyu Jin David Ikumi Huijie Lu Key Laboratory of Environmental Remediation and Ecological Health(Ministry of Education) College of Environmental and Resource SciencesZhejiang UniversityHangzhou 310058China China National Nuclear Corporation Beijing Research Institute of Chemical Engineering and MetallurgyBeijing 100029China College of Environment Zhejiang University of TechnologyHangzhou 310014China Key Laboratory of Ecology and Environment in Minority Areas National Ethnic Affairs CommissionCollege of Life&Environmental SciencesMinzu University of ChinaBeijing 100081China Water Research Group Department of Civil EngineeringUniversity of Cape TownRondebosch 7700South Africa Key Laboratory of Water Pollution Control and Environmental Safety Hangzhou 310058China

The addition of traditional carbon sources(e.g.,acetate)could favor heterotrophic overgrowth in partial denitrification coupled with anammox(PD–A)systems,thus hindering the performance and stability of this novel wastewater nitrogen removal ***,it is necessary to develop an effective,environmentally friendly,and inexpensive *** study demonstrated the potential of formate to enhance the performance and community stability of PD–A under mainstream *** a laboratory-scale biofilm reactor,formate addition(COD/NO_(3)^(–)–N=1.75)improved nitrogen removal efficiency(from 72.1±3.5%to 81.7±2.7%),EPS content(from 106.3±8.1 to 163.0±15.5 mg/gVSS)and increased anammox bacteria growth(predominantly Candidatus Brocadia,from 29.5±0.7%to 34.5±5.4%)while maintaining stable heterotrophs dominated by methylotrophic ***–NanoSIMS revealed a formate uptake using *** and Desulfobacillus,with *** being the major contributor to partial nitrate reduction to *** can synthesize diverse hydrophobic amino acids and provide key nutrients for *** achieve comparable nitrogen removal,the cost of the formate-driven PD–A process should be 11.2%lower than that of *** results greatly enrich our understanding of C1 metabolism represented by formate in anammox communities and its application in the context of coupling partial denitrification–anammox toward enhanced nitrogen removal in global wastewater treatment systems.

关键词： Formate Mixotrophic growth Partial denitrification-anammox Metabolic interaction FISH-NanoSIMS

K doping stabilizes three-dimensional K0.2Na1.3Mn0.5O2-δ as high-performance cathode for sodium-ion batteries

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Rare Metals 2024年第10期43卷 5030-5038页

作者： Jia-Hao Xu you-Huan zhu Wei-Min Yang Hua Cheng Zhou-Guang Lu Industrial Training Center Shenzhen Polytechnic University Department of Materials Science and Engineering Southern University of Science and Technology School of Materials Science and Environmental Engineering Shenzhen Polytechnic University

It is a difficult challenge to simultaneously employ the cationic and anionic redox chemistry in cathode materials for sodium-ion batteries with high *** though layered oxides （classified as two-dimensional oxides） demonstrate excellent promise in the high discharge capacity,their poor oxygen transformation via redox reactions is limited by crystal ***,a doping strategy was conceived to tackle this issue and increase redox efficiency.K doping was applied to transform the two-dimensional Na1.3Mn0.7O2（NMO） to threedimensional K0.2Na1.3Mn0.5O2（KNMO）,preventing the irreversible phase shift and preserving the crystal structure’s stability while *** this modification treatment,KNMO features manganese and oxygen reactive sites,delivering a promising energy density of 190mAh·g-1at 5 mA·g-1in the 2.0–4.5 V voltage range (vs71.4 mAh·g-1for the pristine NMO).Moreover,it displays improved capacity retention of more than 83.5% after 50cycles at 50 mA·*** results demonstrated that doped intercalation oxides were promising for redox oxygen transformation in sodium-ion batteries.

关键词： High-performance cathode Metal ion dopings Sodium-ion batteries Three-dimensional structure

Graded Heterojunction Improves Wide-Bandgap Perovskite for Highly Efficient 4-Terminal Perovskite/Silicon Tandem Solar Cells

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Research 2024年第2期2023卷 181-190页

作者： Wenming chai Lindong Li Weidong zhu Dazheng Chen Long Zhou He Xi Jincheng Zhang Chunfu Zhang Yue Hao State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology&Shaanxi Joint Key Laboratory of Graphene School of MicroelectronicsXidian UniversityXi'anShaanxi 710071China Xi'an Baoxin Solar Technology Co. Ltd.Xi'an710071China

Wide-bandgap(WBG)perovskite solar cells(PSCs)are essential for highly efficient and stable silicon/perovskite tandem solar *** this study,we adopted a synthetic strategy with lead thiocyanate(Pb(SCN)_(2))additive and methylammonium chloride(MACl)posttreatment to enhance the crystallinity and improve the interface of WBG perovskite films with a bandgap of 1.68 *** excessive PbI_(2)was formed at grain boundaries and converted into MAPbI_(3-x)Cl_(x)perovskites,which are utilized to form the graded heterojunction(GHJ)and compressive *** is beneficial for passivating nonradiative recombination defects,suppressing halide phase segregation,and facilitating carrier ***,the device with GHJ delivered a champion efficiency of 20.30%and superior stability in ambient air and under 85℃.Finally,we achieved a recorded efficiency of 30.91%for 4-terminal WBG perovskite/TOPCon tandem silicon solar *** findings demonstrate a promising approach for fabricating efficient and stable WBG PSCs through the formation of GHJ.

关键词： perovskite Graded Highly

Accelerated Sequential Deposition Reaction via Crystal Orientation Engineering for Low-Temperature,High-Efficiency Carbon-Electrode CsPbBr_(3) Solar Cells

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Energy & Environmental Materials 2024年第1期7卷 168-175页

作者： Zeyang Zhang Weidong zhu Tianjiao Han Tianran Wang Wenming chai Jiaduo zhu He Xi Dazheng Chen Gang Lu Peng Dong Jincheng Zhang Chunfu Zhang Yue Hao State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology&Shaanxi Joint Key Laboratory of Graphene School of MicroelectronicsXidian UniversityXi'an 710071China Guangzhou Wide Bandgap Semiconductor Innovation Center Guangzhou institute of technologyXidian UniversityGuangzhou 510555China Qinghai Huanghe Hydropower Development CO. LTD.Xining810008China

Low-temperature,ambient processing of high-quality CsPbBr_(3)films is demanded for scalable production of efficient,low-cost carbon-electrode perovskite solar cells(PSCs).Herein,we demonstrate a crystal orientation engineering strategy of PbBr_(2)precursor film to accelerate its reaction with CsBr precursor during two-step sequential deposition of CsPbBr_(3)*** a novel strategy is proceeded by adding CsBr species into PbBr_(2)precursor,which can tailor the preferred crystal orientation of PbBr_(2)film from[020]into[031],with CsBr additive staying in the film as CsPb_(2)Br_(5)*** calculations show that the reaction energy barrier of(031)planes of PbBr_(2)with CsBr is lower about 2.28 eV than that of(O2O)***,CsPbBr_(3)films with full coverage,high purity,high crystallinity,micro-sized grains can be obtained at a low temperature of 150℃.Carbon-electrode PSCs with these desired CsPbBr_(3)films yield the record-high efficiency of 10.27%coupled with excellent operation ***,the 1 cm^(2)area one with the superior efficiency of 8.00%as well as the flexible one with the champion efficiency of 8.27%and excellent mechanical bending characteristics are also achieved.

关键词： carbon-electrode perovskite solar cells crystal orientation engineering CsPbBr_(3) low temperature two-step sequential deposition