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Multi-objective global optimization approach predicted quasi-layered ternary TiOS crystals with promising photocatalytic properties

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chinese Physics B 2024年第8期33卷 447-454页

作者：向依婕高思妍王春雷方海平段香梅郑益峰张越宇 Shanghai Institute of Applied Physics Chinese Academy of Sciences university of chinese Academy of sciences School of Materials science and Engineering East China University of Science and Technology College of science Shanghai University School of Physics East China University of Science and Technology School of Physical science and technology Ningbo University Wenzhou Institute University of Chinese Academy of Sciences (UCAS)

Titanium dioxide（TiO2） has attracted considerable research attentions for its promising applications in solar cells and photocatalytic ***,the intrinsic challenge lies in the relatively low energy conversion efficiency of TiO2,primarily attributed to the substantial band gaps（exceeding 3.0 eV） associated with its rutile and anatase *** multi-objective global optimization,we have identified two quasi-layered ternary Ti-O-S crystals,composed of titanium,oxygen,and *** calculations of formation energy,phonon dispersions,and thermal stability confirm the chemical,dynamical and thermal stability of these newly discovered *** the state-of-art hybrid density functional approach and many-body perturbation theory（quasiparticle GW approach and Bethe-Salpeter equation）,we calculate the optical properties of both the TiOS ***,both phases show favorable photocatalytic characteristics,featuring band gaps suitable for visible optical absorption and appropriate band alignments with water for effective charge carrier ***,ternary compound TiOS holds the potential for achieving high-efficiency photochemical conversion,showing our multi-objective global optimization provides a new approach for novel environmental and energy materials design with multicomponent compounds.

关键词： first principles calculations multi-objective global optimization photocatalysis

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Li-promoted C3N4 catalyst for efficient isomerization of glucose into fructose at 50℃ in water

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Green Energy & Environment 2024年第9期9卷 1419-1426页

作者： Wang Liu Yanfei Zhang Mengya Sun Xinpeng Zhao Shenggang Li Xinqing Chen Liangshu Zhong Lingzhao Kong CAS Key Laboratory of Low-Carbon Conversion science and Engineering Shanghai Advanced Research Institute Chinese Academy of Sciences university of chinese Academy of sciences School of Physical science and technology Shanghai Tech University School of Environmental science and Engineering Suzhou University of Science and Technology

Efficient and selective glucose-to-fructose isomerization is a crucial step for production of oxygenated chemicals derived from sugars,which is usually catalyzed by base or Lewis acid heterogeneous ***,high yield and selectivity of fructose cannot be simultaneously obtained under mild conditions which hamper the scale of application compared with enzymatic ***,a Li-promoted C3N4catalyst was exploited which afforded an excellent fructose yield （40.3 wt%） and selectivity （99.5%） from glucose in water at 50~oC,attributed to the formation of stable Li–N bond to strengthen the basic sites of ***,the so-formed N6–Li–H2O active site on Li–C3N4catalyst in aqueous phase changes the local electronic structure and strengthens the deprotonation process during glucose isomerization into *** superior catalytic performance which is comparable to biological pathway suggests promising applications of lithium containing heterogeneous catalyst in biomass refinery.

关键词： Glucose Fructose Isomerization Li–C 3 N 4 Density functional theory calculations

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Identifying malicious traffic under concept drift based on intraclass consistency enhanced variational autoencoder

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science China(Information sciences) 2024年第8期67卷 238-252页

作者： Xiang LUO Chang LIU Gaopeng GOU Gang XIONG Zhen LI Binxing FANG Institute of Information Engineering Chinese Academy of Sciences School of Cyber Security University of Chinese Academy of Sciences School of Computer science and technology Harbin Institute of Technology (Shenzhen)

Accurate identification of malicious traffic is crucial for implementing effective defense countermeasures and has led to extensive research efforts. However, the continuously evolving techniques employed by adversaries have introduced the issues of concept drift, which significantly affects the performance of existing methods. To tackle this challenge, some researchers have focused on improving the separability of malicious traffic representation and designing drift detectors to reduce the number of false ***, these methods often overlook the importance of enhancing the generalization and intraclass consistency in the representation. Additionally, the detectors are not sufficiently sensitive to the variations among different malicious traffic classes, which results in poor performance and limited robustness. In this paper, we propose intraclass consistency enhanced variational autoencoder with Class-Perception detector(ICE-CP) to identify malicious traffic under concept drift. It comprises two key modules during training:intraclass consistency enhanced(ICE) representation learning and Class-Perception(CP) detector construction. In the first module, we employ a variational autoencoder(VAE) in conjunction with Kullback-Leibler(KL)-divergence and cross-entropy loss to model the distribution of each input malicious traffic flow. This approach simultaneously enhances the generalization, interclass consistency, and intraclass differences in the learned representation. Consequently, we obtain a compact representation and a trained classifier for nondrifting malicious traffic. In the second module, we design the CP detector, which generates a centroid and threshold for each malicious traffic class separately based on the learned representation, depicting the boundaries between drifting and non-drifting malicious traffic. During testing, we utilize the trained classifier to predict malicious traffic classes for the testing samples. Then, we use the CP det

关键词： concept drift malicious traffic identification variational autoencoder intrusion detection cyberspace security

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Reliability of DC-link capacitor in pulsed power supply for accelerator magnet

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Nuclear science and Techniques 2024年第9期35卷 28-40页

作者： Jie Wang Da-Qing Gao Wan-Zeng Shen Hong-Bin Yan Li-Jun Mao Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear science and technology Lanzhou UniversityLanzhou 730000China School of Nuclear science and technology University of Chinese Academy of SciencesBeijing 100049China

Capacitors are widely used in pulsed magnet power supplies to reduce ripple voltage,store energy,and decrease power *** this study,DC-link capacitors in pulsed power supplies were *** deriving an analytical method for the capacitor current on the H-bridge topology side,the root-mean-square value of the capacitor current was calculated,which helps in selecting the DC-link *** proposed method solves this problem quickly and with high *** current reconstruction of the DC-link capacitor is proposed to avoid structural damage in the capacitor’s current measurement,and the capacitor’s hotspot temperature and temperature rise are calculated using the FFT *** test results showed that the error between the calculated and measured temperature increases was within 1.5℃.Finally,the lifetime of DC-link capacitors was predicted based on Monte Carlo *** proposed method can evaluate the reliability of DC-link capacitors in a non-isolated switching pulsed power supply for accelerators and is also applicable to film capacitors.

关键词： Aluminum electrolytic capacitor DC-link current DC–DC power converter Hotspot temperature

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Quantum search with prior knowledge

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science China(Information sciences) 2024年第9期67卷 321-329页

作者： Xiaoyu HE Xiaoming SUN Jialing ZHANG State Key Lab of Processors Institute of Computing Technology Chinese Academy of Sciences School of Computer science and technology University of Chinese Academy of Sciences

The combination of contextual side information and search is a powerful paradigm in the scope of artificial intelligence. The prior knowledge enables the identification of possible solutions but may be imperfect. Contextual information can arise naturally, for example in game AI where prior knowledge is used to bias move decisions. In this work we investigate the problem of taking quantum advantage of contextual information, especially searching with prior knowledge. We propose a new generalization of Grover's search algorithm that achieves the optimal expected success probability of finding the solution if the number of queries is fixed. Experiments on small-scale quantum circuits verify the advantage of our algorithm. Since contextual information exists widely, our method has wide applications. We take game tree search as an example.

关键词： quantum computing quantum search quantum query algorithm prior knowledge

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Studies of an event-building algorithm of the readout system for the twin TPCs in HFRS

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Nuclear science and Techniques 2024年第4期35卷 82-95页

作者： Jing Tian Zhi-Peng Sun Song-Bo Chang Yi Qian Hong-Yun Zhao Zheng-Guo Hu Xi-Meng Chen Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear science and technology University of LanzhouLanzhou 730000China School of Nuclear science and technology University of Chinese Academy of SciencesBeijing 100049China Advanced Energy science and technology Guangdong LaboratoryHuizhou 516000China

The High-energy Fragment Separator(HFRS),which is currently under construction,is a leading international radioactive beam *** sets of position-sensitive twin time projection chamber(TPC)detectors are distributed on HFRS for particle identification and beam *** twin TPCs'readout electronics system operates in a trigger-less mode due to its high counting rate,leading to a challenge of handling large amounts of *** address this problem,we introduced an event-building *** algorithm employs a hierarchical processing strategy to compress data during transmission and *** addition,it reconstructs twin TPCs'events online and stores only the reconstructed particle information,which significantly reduces the burden on data transmission and storage *** studies demonstrated that the algorithm accurately matches twin TPCs'events and reduces more than 98%of the data volume at a counting rate of 500 kHz/channel.

关键词： High counting rate Twin TPCs Trigger-less Readout electronics Event building Hierarchical data processing

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Tailoring Ni based catalysts by indium for the dehydrogenative coupling of ethanol into ethyl acetate

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Green Energy & Environment 2024年第8期9卷 1321-1331页

作者： Ming Yin Jifeng Pang Jin Guo Xianquan Li Yujia Zhao Pengfei Wu Mingyuan Zheng CAS Key Laboratory of science and technology on Applied Catalysis Dalian Institute of Chemical PhysicsChinese Academy of Sciences university of chinese Academy of sciences School of Materials science and Engineering Dalian Jiaotong University

Exploring stable and robust catalysts to replace the current toxic CuCr based catalysts for dehydrogenative coupling of ethanol to ethyl acetate is a challenging but promising ***,novel NiIn based catalysts were developed by tailoring Ni catalysts with Indium （In） for this *** the optimal Ni0.1Zn0.7Al0.3InOx catalyst,the ethyl acetate selectivity reached 90.1%at 46.2%ethanol conversion under the conditions of 548 K and a weight hourly space velocity of 1.9 h-1in the 370 h time on ***,the ethyl acetate productivity surpassed1.1 gethyl acetateg-1catalysth-1,one of the best performance in current *** to catalyst characterizations and conditional experiments,the active sites for dehydrogenative coupling of ethanol to ethyl acetate were proved to be Ni4In *** presence of In tailored the chemical properties of Ni,and subsequently inhibited the C±C cracking and/or condensation reactions during ethanol *** Ni4In alloy sites,ethanol was dehydrogenated into acetaldehyde,and then transformed into acetyl species with the removal of H ***,the coupling between acetyl species and surface-abundant ethoxyde species into ethyl acetate was achieved,affording a high ethyl acetate selectivity and catalyst stability.

关键词： Dehydrogenative coupling Ethanol Ethyl acetate Nickel and indium alloys

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Experimental investigation of dynamic characteristics of leaching tubing for solution mining of salt cavern carbon and energy storage

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Petroleum science 2024年第4期21卷 2703-2722页

作者： Yin-Ping Li Xin-Bo Ge Xi-Lin Shi Hong-Ling Ma State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences university of chinese Academy of sciences College of Energy and Mining Engineering Shandong University of Science and Technology State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of science and technology Shandong University of Science and Technology

Salt caverns are extensively utilized for storing various substances such as fossil energy, hydrogen,compressed air, nuclear waste, and industrial solid waste. In China, when the salt cavern is leached through single-well water solution mining with oil as a cushion, engineering challenges arise with the leaching tubing, leading to issues like damage and instability. These problems significantly hinder the progress of cavern construction and the control of cavern shape. The primary cause of this is the flowinduced vibration instability of leaching tubing within a confined space, which results in severe bending or damage to the tubing. This study presents a model experimental investigation on the dynamic characteristics of leaching tubing using a self-developed liquid-solid coupling physical model experiment apparatus. The experiment utilizes a silicone-rubber pipe(SRP) and a polycarbonate pipe(PCP) to examine the effects of various factors on the dynamic stability of cantilevered pipes conveying fluid. These factors include external space constraint, flexural rigidity, medium outside the pipe, overhanging length, and end conditions. The experiments reveal four dynamic response phenomena: water hammer, static buckling, chaotic motion, and flutter instability. The study further demonstrates that the length of the external space constraint has a direct impact on the flutter critical flow velocity of the cantilevered pipe conveying fluid. Additionally, the flutter critical flow velocity is influenced by the end conditions and different external media.

关键词： Salt cavern storage Solution mining Leaching tubing Experimental investigation Flutter instability

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The Exchange Attack and the Mixture Differential Attack Revisited: From the Perspective of Automatic Evaluation

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chinese Journal of Electronics 2024年第1期33卷 19-29页

作者： Kexin QIAO Zhiyu ZHANG Zhongfeng NIU Liehuang ZHU School of Cyberspace science and technology Beijing Institute of Technology State Key Laboratory of Cryptology Institute of Information Engineering Chinese Academy of Sciences School of Cryptography University of Chinese Academy of Sciences

Recent results show that the differential properties within quadruples boom as a new inspiration in cryptanalysis of Advanced Encryption Standard(AES)-like constructions. These methods include the exchange attack proposed in Asiacrypt’19, the mixture differential attack proposed in To SC’18, etc., where the essential properties are obtained by manually scrutinizing the structures of the AES-like constructions. This paper presents a novel framework and an automatic tool based on mixed integer linear programming to search for mixture differential distinguishers for general constructions. This framework considers what equality patterns among quadruples can make a distinguisher and traces how the patterns propagate through cipher components with accurate probability *** this tool, a 5-round AES distinguishing attack with lower complexity and more 6-round distinguishing attacks in the chosen plaintext scenarios are deduced. We prove that no exchange-type or mixture differential distinguisher exists for 7 and above rounds AES if the details of the Sbox and Mix Columns matrix are not taken into account.

关键词： Ciphers Estimation Encryption Mixed integer linear programming Complexity theory Standards

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Online Nonstop Task Management for Storm-Based Distributed Stream Processing Engines

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Journal of Computer science & technology 2024年第1期39卷 116-138页

作者：张洲金培权谢希科王晓亮刘睿诚万寿红 School of Computer science and technology University of Science and Technology of ChinaHefei 230026China Key Laboratory of Electromagnetic Space Information Chinese Academy of SciencesHefei 230026China

Most distributed stream processing engines(DSPEs)do not support online task management and cannot adapt to time-varying data ***,some studies have proposed online task deployment algorithms to solve this ***,these approaches do not guarantee the Quality of Service(QoS)when the task deployment changes at runtime,because the task migrations caused by the change of task deployments will impose an exorbitant *** study one of the most popular DSPEs,Apache Storm,and find out that when a task needs to be migrated,Storm has to stop the resource(implemented as a process of Worker in Storm)where the task is *** will lead to the stop and restart of all tasks in the resource,resulting in the poor performance of task *** to solve this problem,in this pa-per,we propose N-Storm(Nonstop Storm),which is a task-resource decoupling DSPE.N-Storm allows tasks allocated to resources to be changed at runtime,which is implemented by a thread-level scheme for task ***,we add a local shared key/value store on each node to make resources aware of the changes in the allocation ***,each resource can manage its tasks at *** on N-Storm,we further propose Online Task Deployment(OTD).Differ-ing from traditional task deployment algorithms that deploy all tasks at once without considering the cost of task migra-tions caused by a task re-deployment,OTD can gradually adjust the current task deployment to an optimized one based on the communication cost and the runtime states of *** demonstrate that OTD can adapt to different kinds of applications including computation-and communication-intensive *** experimental results on a real DSPE cluster show that N-Storm can avoid the system stop and save up to 87%of the performance degradation time,compared with Apache Storm and other state-of-the-art *** addition,OTD can increase the average CPU usage by 51%for computation-intensive application

关键词： distributed stream processing engine(DSPE) Apache Storm online task migration online task deployment

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