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Impacts of multi-foulings on salinity gradient energy conversion process in negatively charged conical nanochannels

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science china(Technological sciences) 2024年第6期67卷 1714-1726页

作者： MAO RuiJie CHEN Xi ZHOU RuHong LONG Rui LIU ZhiChun LIU Wei school of Energy and Power Engineering Huazhong University of Science and TechnologyWuhan430074China china-EU Institute for Clean and Renewable Energy Huazhong University of Science and TechnologyWuhan430074China school of Mechanical science and Engineering Huazhong University of Science and TechnologyWuhan430074China

Membrane fouling inevitably occurs during nanofluidic reverse ***,the impact of multi-fouling on the energy conversion performance of negatively charged conical nanochannels under asymmetrical configurations is systematically *** results reveal that in Configuration I,where a high-concentration solution is applied at the tip side,at small concentration ratios,multiple foulings reduce the electric *** Configuration II,where a low-concentration solution is applied at the tip side,multiple foulings near the base side contribute to the electric *** fouling that formed near the lowconcentration entrance diminished the electric power and energy conversion ***-fouling lowered the electrical power consumption by 69.27%and 99.94%in Configurations I and II,*** Configuration I,the electric power first increased with increasing fouling surface charge density,reached its maximum value,and thereafter *** Configuration II,the electric power first decreased with increasing fouling surface charge density,reached its minimum value,and thereafter *** negative or positive charge densities of fouling contribute to the electric power and energy conversion efficiency.

关键词： conical nanochannel fouling nanofluidic reverse electrodialysis salinity gradient energy

Robust video question answering via contrastive cross-modality representation learning

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science china(Information sciences) 2024年第10期67卷 211-226页

作者： Xun YANG Jianming ZENG Dan GUO Shanshan WANG Jianfeng DONG Meng WANG school of Information science and technology University of Science and Technology of China Institute of Artificial Intelligence Hefei Comprehensive National Science Center school of Computer science and Information Engineering Hefei University of Technology Institutes of Physical science and Information technology Anhui University school of Computer science and technology Zhejiang Gongshang University

Video question answering(VideoQA) is a challenging yet important task that requires a joint understanding of low-level video content and high-level textual semantics. Despite the promising progress of existing efforts, recent studies revealed that current VideoQA models mostly tend to over-rely on the superficial correlations rooted in the dataset bias while overlooking the key video content, thus leading to unreliable results. Effectively understanding and modeling the temporal and semantic characteristics of a given video for robust VideoQA is crucial but, to our knowledge, has not been well investigated. To fill the research gap, we propose a robust VideoQA framework that can effectively model the cross-modality fusion and enforce the model to focus on the temporal and global content of videos when making a QA decision instead of exploiting the shortcuts in datasets. Specifically, we design a self-supervised contrastive learning objective to contrast the positive and negative pairs of multimodal input, where the fused representation of the original multimodal input is enforced to be closer to that of the intervened input based on video perturbation. We expect the fused representation to focus more on the global context of videos rather than some static keyframes. Moreover, we introduce an effective temporal order regularization to enforce the inherent sequential structure of videos for video representation. We also design a Kullback-Leibler divergence-based perturbation invariance regularization of the predicted answer distribution to improve the robustness of the model against temporal content perturbation of videos. Our method is model-agnostic and can be easily compatible with various VideoQA backbones. Extensive experimental results and analyses on several public datasets show the advantage of our method over the state-of-the-art methods in terms of both accuracy and robustness.

关键词： video question answering cross-modality fusion contrastive learning cross-media reasoning

The role of strain in oxygen evolution reaction

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Journal of Energy Chemistry 2024年第6期93卷 322-344,I0009页

作者： Zihang Feng Chuanlin Dai Zhe Zhang Xuefei Lei Wenning Mu Rui Guo Xuanwen Liu Junhua You school of Materials science and Engineering Northeastern UniversityShenyang 110819LiaoningChina school of Materials science and technology Shenyang University of TechnologyShenyang 110870LiaoningChina

The oxygen evolution reaction(OER)is a crucial step in metal-air batteries and water splitting technologies,playing a significant role in the efficiency and achievable heights of these two ***,the OER is a four-step,four-electron reaction,and its slow kinetics result in high overpotentials,posing a *** address this issue,numerous strategies involving modified catalysts have been proposed and proven to be highly *** these strategies,the introduction of strain has been widely reported because it is generally believed to effectively regulate the electronic structure of metal sites and alter the adsorption energy of catalyst surfaces with reaction ***,strain has many other effects that are not well known,making it an important yet unexplored *** on this,this review provides a detailed introduction to the various roles of strain in *** better explain these roles,the review also presents the definition of strain and elucidates the potential mechanisms of strain in OER based on the d-band center theory and adsorption volcano ***,the review showcases various ways of introducing strain in OER through examples reported in the latest literature,aiming to provide a comprehensive perspective for the development of strain ***,the review analyzes the appropriate proportion of strain introduction,compares compressive and tensile strain,and examines the impact of strain on *** the review offers prospects for future research directions in this emerging field.

关键词： Oxygen evolution reaction Strain generation Tensile strain Compressive strain Strain mechanism Strain effects

Cocrystals of carbamazepine:Structure,mechanical properties,fluorescence properties,solubility,and dissolution rate

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Particuology 2024年第7期90卷 20-30页

作者： Jinbo Ouyang Lishan Liu Yin Li Mingyang Chen Limin Zhou Zhirong Liu Li Xu Hamza Shehzad school of Chemistry and Materials science East China University of TechnologyNanchang 330013China school of Physics and Materials science Nanchang UniversityNanchang 330013China school of Chemical Engineering and technology Tianjin UniversityTianjin 300072China

Carbamazepine(CBZ)is an anticonvulsant with very low water solubility,presenting as a white crystalline powder with poor mechanical properties and is hard to *** enhance CBZ's physicochemical properties,such as water solubility and mechanical properties,we selected six cocrystal coformers(CCFs):nicotinamide(NIC),benzamide(BZM),salicylic acid(SCA),fumaric acid(FMA),trimesic acid(TMA),and hesperetin(HPE).Six CBZ cocrystals were successfully prepared using the solution *** transform infrared spectroscopy(FT-IR),powder X-ray diffraction(PXRD),differential scanning calorimetry(DSC),and single crystal X-ray diffraction(SCXRD)were used to characterize the crystal structures and gain comprehensive insights into the six *** mechanical,fluorescence,and solubility properties of the six cocrystals were *** results reveal that most of the prepared cocrystals exhibit improved water solubility and mechanical properties when compared to *** them,the dissolution rate of cocrystals excluded from CBZ-HPE has increased by an average of 3 or 4 times compared to CBZ,while CBZ-HPE exhibits superior mechanical ***,all six cocrystals possess better fluorescence performance than *** thoroughly evaluated the mechanical properties of the cocrystals through both experimental and theoretical *** work provides a new direction for studying drug cocrystals to improve the physicochemical properties of drugs.

关键词： Carbamazepine Cocrystal Mechanical properties Fluorescence performance Dissolution rate

Adverse effect of niobium and boron on hot deformation behavior of sulfur-containing steel

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Journal of Iron and Steel Research International 2024年第1期31卷 252-263页

作者： Guo-ning He Shi-qi Wan Bo Jiang Chao-lei Zhang Ya-zheng Liu Chun-jing Wu school of Materials science and Engineering University of Science and Technology BeijingBeijing100083China Institute for Advanced Materials and technology University of Science and Technology BeijingBeijing100083China

The hot deformation behaviors of sulfur-containing gear steel 20MnCr5 containing three different contents of Nb and B(0,0.021%Nb,and 0.024%Nb-0.0022%B)were *** compression and tenssion tests were carried out by Gleeble3800 at the austenite region from 850 to 1150℃and the adverse effects of Nb and B were analyzed by the fracture,microstructure and precipitate *** compression tests showed that the proportions of instable area in hot processing maps of 0.021%Nb and Nb-B steels were higher and the deformability of Nb free steel was *** tensile deformation experiments showed that the reduction areas of Nb free,0.021%Nb and Nb-B steels were 92%-99%,84%-98%and 67%-97%,*** addition of Nb or Nb and B inhibited the dynamic recrystallization during hot deformation,and consequently,more deformed grains were then formed in 0.021%Nb and Nb-B steels thus to obtain the microstructure with worse uniformity and then deteriorate the *** addition,the interaction between inclusions and microalloyed elements was also *** particles of 0.021%Nb and Nb-B steels dynamically precipitated during deformation and precipitated together with MnS thus to worsen the deformability,resulting in the decrease of reduction area.

关键词： Hot deformation Gear steel Processing map Dynamic recrystallization Microalloying

Nonreciprocal thermal metamaterials:Methods and applications

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1678-1693页

作者： Zhengjiao Xu Chuanbao Liu Xueqian Wang Yongliang Li Yang Bai Institute for Advanced Material and technology University of Science and Technology BeijingBeijing 100083China school of Materials science and Engineering University of Science and Technology BeijingBeijing 100083China

Nonreciprocity of thermal metamaterials has significant application prospects in isolation protection,unidirectional transmission,and energy ***,due to the inherent isotropic diffusion law of heat flow,it is extremely difficult to achieve nonreciprocity of heat *** review presents the recent developments in thermal nonreciprocity and explores the fundamental theories,which underpin the design of nonreciprocal thermal metamaterials,i.e.,the Onsager reciprocity ***,three methods for achieving nonreciprocal metamaterials in the thermal field are elucidated,namely,nonlinearity,spatiotemporal modulation,and angular momentum bias,and the applications of nonreciprocal thermal metamaterials are *** also discuss nonreciprocal thermal ***,the potential applications of nonreciprocity to other Laplacian physical fields are ***,the prospects for advancing nonreciprocal thermal metamaterials are highlighted,including developments in device design and manufacturing techniques and machine learning-assisted material design.

关键词： thermal metamaterials nonreciprocity nonlinearity spatiotemporal modulation

Hybrid concurrency control protocol for data sharing among heterogeneous blockchains

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Frontiers of Computer science 2024年第3期18卷 1-12页

作者： Tiezheng GUO Zhiwei ZHANG Ye YUAN Xiaochun YANG Guoren WANG school of Computer science and technology Beijing Institute of TechnologyBeijing 100029China school of Computer science and Engineering Northeastern UniversityShenyang 110167China

With the development of information technology and cloud computing,data sharing has become an important part of scientific *** traditional data sharing,data is stored on a third-party storage platform,which causes the owner to lose control of the *** a result,there are issues of intentional data leakage and tampering by third parties,and the private information contained in the data may lead to more significant ***,data is frequently maintained on multiple storage platforms,posing significant hurdles in terms of enlisting multiple parties to engage in data sharing while maintaining *** this work,we propose a new architecture for applying blockchains to data sharing and achieve efficient and reliable data sharing among heterogeneous *** design a new data sharing transaction mechanism based on the system architecture to protect the security of the raw data and the processing *** also design and implement a hybrid concurrency control protocol to overcome issues caused by the large differences in blockchain performance in our system and to improve the success rate of data sharing *** took Ethereum and Hyperledger Fabric as examples to conduct crossblockchain data sharing *** results show that our system achieves data sharing across heterogeneous blockchains with reasonable performance and has high scalability.

关键词： data sharing blockchain concurrency control protocol crosschain

Electron kinetic effects in back-stimulated Raman scattering bursts driven by broadband laser pulses

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Matter and Radiation at Extremes 2024年第4期9卷 54-67页

作者： Q.K.Liu L.Deng Q.Wang X.Zhang F.Q.Meng Y.P.Wang Y.Q.Gao H.B.Cai S.P.Zhu graduate school China Academy of Engineering PhysicsBeijing 100088China Institute of Applied Physics and Computational Mathematics Beijing 100094China school of Nuclear science and technology University of Science and Technology of ChinaHefei 230026China Shanghai Institute of Laser Plasma Shanghai 201800China HEDPS Center for Applied Physics and TechnologyPeking UniversityBeijing 100871China school of Physics Zhejiang UniversityHangzhou 310027China

We examine electron kinetic effects in broadband-laser-driven back-stimulated Raman scattering(BSRS)bursts using particle-in-cell *** bursts occur during the nonlinear stage,causing reflectivity spikes and generating large numbers of hot ***-duration simulations are performed to observe burst events,and a simplified model is developed to eliminate the interference of the broadband laser’s random intensity *** the simplified model,we isolate and characterize the spectrum of electron plasma *** spectrum changes from a sideband structure to a turbulence-like structure during the burst.A significant asymmetry in the spectrum is *** asymmetry is amplified and transferred to electron phase space by high-intensity broadband laser pulses,leading to violent vortex-merging and generation of hot *** proportion of hot electrons increases from 6.76%to 14.7%during a single violent burst *** demonstrate that kinetic effects profoundly influence the BSRS evolution driven by broadband lasers.

关键词： scattering kinetic simplified

Grain boundary engineering for enhancing intergranular damage resistance of ferritic/martensitic steel P92

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Nuclear science and Techniques 2024年第5期35卷 186-199页

作者： Lei Peng Shang-Ming Chen Jing-Yi Shi Yong-Jie Sun Yi-Fei Liu Yin-Zhong Shen Hong-Ya He Hui-Juan Wang Jie Tian State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China school of Nuclear science and technology University of Science and Technology of ChinaHefei 230027China school of Materials Engineering Shanghai University of Engineering Science333 Long Teng RoadShanghai 201620China Experimental Center of Engineering and Material science University of Science and Technology of ChinaHefei 230026China

Ferritic/martensitic(F/M)steel is widely used as a structural material in thermal and nuclear power ***,it is susceptible to intergranular damage,which is a critical issue,under service *** this study,to improve the resistance to intergranular damage of F/M steel,a thermomechanical process(TMP)was employed to achieve a grain boundary engineering(GBE)microstructure in F/M steel *** TMP,including cold-rolling thickness reduction of 6%,9%,and 12%,followed by austenitization at 1323 K for 40 min and tempering at 1053 K for 45 min,was applied to the as-received(AR)P92 *** prior austenite grain(PAG)size,prior austenite grain boundary character distribution(GBCD),and connectivity of prior austenite grain boundaries(PAGBs)were *** to the AR specimen,the PAG size did not change *** fraction of coincident site lattice boundaries(CSLBs,3≤Σ≤29)and Σ3^(n) boundaries along PAGBs decreased with increasing reduction ratio because the recrystallization fraction increased with increasing reduction *** PAGB connectivity of the 6%deformed specimen slightly deteriorated compared with that of the AR ***,potentiodynamic polarization studies revealed that the intergranular damage resistance of the studied steel could be improved by increasing the fraction of CSLBs along the PAGBs,indicating that the TMP,which involves low deformation,could enhance the intergranular damage resistance.

关键词： Grain boundary engineering Ferritic/martensitic steel Prior austenite grain boundary character distribution Grain boundary connectivity Intergranular damage resistance