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Torsional Vibrations of a Cantilever with Lateral Friction in a Resonance Friction Microscope

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Chinese Physics Letters 2012年第1期29卷 53-55页

作者： CHEN Jian-Song GE Yun ZHANG Hui school of Mechanical Engineering Southeast UniversityNanjing 211189 school of Electronics Science and Engineering Nanjing UniversityNanjing 210093 Laboratory of Modern Acoustics Institute of AcousticsNanjing UniversityNanjing 210093

A model of fundamental torsional vibration of a cantilever with lateral friction is presented by using the harmonic balance *** model demonstrates that the torsional vibration has close relations with the lateral friction threshold,the lateral contact stiffness and the torsional vibration amplitude of the *** the threshold is larger than a product of the stiffness and the vibration amplitude,the lateral friction is a linear force with the *** the lateral friction threshold is less than the product,the motions of the tip on the sample can be stick-slip or slip *** results are useful to optimize and to manipulate the fundamental flexural vibration of the piezo-cantilever,and give an insight into the tribological characterization of the interface in a resonance friction microscope.

关键词： friction torsional cantilever

Electronic Data Preservation and Storage of Evidence by Blockchain

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Journal of Forensic Science and Medicine 2020年第1期6卷 27-36页

作者： Hua Shang Hui Qiang school of Humanities and law North China University of TechnologyBeijingChina Institute for Chinese Legal Modernization Studies School of LawNanjing Normal UniversityNanjingJiangsuChina

In the face of the era of big data,how to ensure the authenticity of electronic data has become an important practical *** preservation methods based on hash operation,time stamp,and blockchain technology can effectively guarantee the authenticity and security of electronic *** are inherently traceable,de‑centralized,and difficult to tamper with,which can be enough served as the basic technology of electronic data *** by blockchain mainly includes the following links:platform registration and identity authentication,generation and transmission of electronic data,and storage of electronic *** by blockchain has higher security than centralized online security because of distributed ***,it should be acknowledged that the preservation by blockchain is not without *** court should adhere to the principle of individual review of each case and review the electronic data from its generation,transmission,reception,storage,and collection.

关键词： Electronic data online evidence preservation preservation by blockchain

Sulfur-driven methylmercury production in paddies continues following soil oxidation

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Journal of Environmental Sciences 2022年第9期34卷 166-174页

作者： Wenli Tang Chao Tang Pei Lei school of the Environment State Key Laboratory of Pollution Control and Resource ReuseNanjing UniversityNanjing 210023China school of Environment Nanjing Normal UniversityNanjing 210023China

Methylmercury(MeHg) production in paddy soils and its accumulation in rice raise global concerns since rice consumption has been identified as an important pathway of human exposure to MeHg. Sulfur(S) amendment via fertilization has been reported to facilitate Hg methylation in paddy soils under anaerobic conditions, while the dynamic of S-amendment induced MeHg production in soils with increasing redox potential remains unclear. This critical gap hinders a comprehensive understanding of Hg biogeochemistry in rice paddy system which is characterized by the fluctuation of redox potential. Here, we conducted soil incubation experiments to explore MeHg production in slow-oxidizing paddy soils amended with different species of S and doses of sulfate. Results show that the elevated redox potential(1) increased MeHg concentrations by 10.9%-35.2%, which were mainly attributed to the re-oxidation of other S species to sulfate and thus the elevated abundance of sulfatereducing bacteria, and(2) increased MeHg phytoavailability by up to 75% due to the reductions in acid volatile sulfide(AVS) that strongly binds MeHg in soils. Results obtained from this study call for attention to the increased MeHg production and phytoavailability in paddy soils under elevated redox potentials due to water management, which might aggravate the MeHg production induced by S fertilization and thus enhance MeHg accumulation in rice.

关键词： Mercury Sulfur Availability Mercury methylation Rice

Thickness-dependent magnetic properties in Pt/[Co/Ni]_(n) multilayers with perpendicular magnetic anisotropy

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Chinese Physics B 2023年第1期32卷 503-508页

作者：晏春杰陈丽娜周恺元杨留鹏付清为王文强岳文诚梁力克陶醉杜军王永磊刘荣华 National Laboratory of Solid State Microstructures School of Physics and Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China school of Science Nanjing University of Posts and TelecommunicationsNanjing 210023China school of Electronics Science and Engineering Nanjing UniversityNanjing 210093China

We systematically investigated the Ni and Co thickness-dependent perpendicular magnetic anisotropy(PMA)coefficient,magnetic domain structures,and magnetization dynamics of Pt(5 nm)/[Co(t_(Co))/Ni(t_(Ni))]_(5)/Pt(1 nm)multilayers by combining the four standard magnetic characterization *** magnetic-related hysteresis loops obtained from the field-dependent magnetization M and anomalous Hall resistivity(AHR)ρxy showed that the two serial multilayers with t_(Co)=0.2 nm and 0.3 nm have the optimum PMA coefficient K_(U) as well as the highest coercivity H_(C) at the Ni thickness t_(Ni)=0.6 ***,the magnetic domain structures obtained by magneto-optic Kerr effect(MOKE)microscopy also significantly depend on the thickness and K_(U) of the ***,the thickness-dependent linewidth of ferromagnetic resonance is inversely proportional to K_(U) and H_(C),indicating that inhomogeneous magnetic properties dominate the ***,the intrinsic Gilbert damping constant determined by a linear fitting of the frequency-dependent linewidth does not depend on the Ni thickness and K_(U).Our results could help promote the PMA[Co/Ni]multilayer applications in various spintronic and spin-orbitronic devices.

关键词： perpendicular magnetic anisotropy magnetic domain damping multiayers

Narrow-disperse Highly Cross-linked “Living” Polymer Microspheres by Two-stage Precipitation Polymerization

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Chinese Journal of Polymer Science 2015年第3期33卷 422-432页

作者： Ying Liu Di Wu Kun Zhang Xiao-shuang Yin 杨文忠 school of Science Nanjing University of Technology

Narrow-disperse, surface-functionalized ＂living＂ polymer microspheres with uniformly cross-linked structures were prepared by two-stage precipitation copolymerization of styrene and divinylbenzene. The two-stage precipitation polymerization is composed of an initial conventional precipitation polymerization for the nucleation followed by a reverse atom transfer radical polymerization （reverse ATRP） for the controlled polymerization process. The polymerization parameters （including reaction time for the first stage, AIBN amount and monomer loading） have been studied to show significant influences on the morphologies. Moreover, narrower size distribution and an ATRP initiator-functional surface of resulting particles can be obtained by applying reverse ATRP to conventional precipitation polymerization in the second stage. Furthermore, the ＂livingness＂ of the resulting polymer microspheres was testified by their surface modification of poly[2-（dimethylamino） ethyl methacrylate] （PDMAEMA） brushes via surface-initiated ATRP （SI-ATRP）.

关键词： ATRP Precipitation polymerization Particle nucleation Surface-initiated Two-stage.

Microporous polythiophene(MPT)-guest complex derived magnetic metal sulfides/carbon nanocomposites for broadband electromagnetic wave absorption

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Journal of Materials Science & Technology 2022年第5期100卷 206-215页

作者： Yingzhi Jiao Siyao Cheng Fan Wu Jiaoyan Shi Aming Xie Xufei Zhu Wei Dong school of Chemical Engineering Nanjing University of Science&TechnologyNanjing 210094China school of Mechanical Engineering Nanjing University of Science&TechnologyNanjing 210094China

Electrical and magnetic properties are two crucial factors for the designing of broadband electromagnetic wave absorption(EWA)*** this work,we synthesized various magnetic metal sulfides/carbon(M_(x)S_(y)/C)nanocomposites from the precursor complex of metal in microporous polythiophene(MPT),and systematically investigated their EWA properties and *** characterization results indicate that M_(x)S_(y) were determined to be Fe_(7)S_(8)/C,Co_(9)S_(8)/C and Ni_(4)S_(3)/C,*** is observed that M_(x)S_(y)/C nanocomposites exhibit remarkable EWA performances,where the maximal absorption gets to-51.3 dB,and efficient absorption can be realized in 10.32-18 GHz(7.68 GHz),which is superior to most reported magnetic carbonaceous EWA ***,the efficient absorption can be tuned to cover Ku band X band,demonstrating their great potential in practical *** conductance loss,obvious polarization relaxation,and apparent eddy current loss are deemed to make the predominant contributions to the high-performance *** research opens up the exploration of novel nanocomposite coupling dielectric loss and magnetic loss using MPT-metal complex precursor for EWA applications.

关键词： Microporous polythiophene Metal sulfide Carbon composite Conjugated microporous polymer Electromagnetic wave absorption

Self-corrected unsupervised domain adaptation

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Frontiers of Computer Science 2022年第5期16卷 35-43页

作者： Yunyun WANG Chao WANG Hui XUE Songcan CHEN school of Computer Science and Engineering Nanjing University of Posts&TelecommunicationsNanjing 210046China school of Computer Science and Engineering Southeast UniversityNanjing 210096China school of Computer Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210023China

Unsupervised domain adaptation(UDA),which aims to use knowledge from a label-rich source domain to help learn unlabeled target domain,has recently attracted much *** methods mainly concentrate on source classification and distribution alignment between domains to expect the correct target *** in this paper,we attempt to learn the target prediction end to end directly,and develop a Self-corrected unsupervised domain adaptation(SCUDA)method with probabilistic label *** adopts a probabilistic label corrector to learn and correct the target labels ***,besides model parameters,those target pseudo-labels are also updated in learning and corrected by the anchor-variable,which preserves the class candidates for *** on real datasets show the competitiveness of SCUDA.

关键词： unsupervised domain adaptation adversarial Learning deep neural network pseudo-labels label corrector

Feature-Grounded Single-Stage Text-to-Image Generation

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Tsinghua Science and Technology 2024年第2期29卷 469-480页

作者： Yuan Zhou Peng Wang Lei Xiang Haofeng Zhang school of Artificial Intelligence Nanjing University of Information Science and TechnologyNanjing 210044China school of Computer Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China

Recently,Generative Adversarial Networks(GANs)have become the mainstream text-to-image(T2I)***,a standard normal distribution noise of inputs cannot provide sufficient information to synthesize an image that approaches the ground-truth image ***,the multistage generation strategy results in complex T2I ***,this study proposes a novel feature-grounded single-stage T2I model,which considers the“real”distribution learned from training images as one input and introduces a worst-case-optimized similarity measure into the loss function to enhance the model's generation *** results on two benchmark datasets demonstrate the competitive performance of the proposed model in terms of the Frechet inception distance and inception score compared to those of some classical and state-of-the-art models,showing the improved similarities among the generated image,text,and ground truth.

关键词： text-to-image(T2I) feature-grounded single-stage generation Generative Adversarial Network(GAN)

Degradation of Azo dye direct black BN based on adsorption and microwave-induced catalytic reaction

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Frontiers of Environmental Science & Engineering 2018年第1期12卷 71-83页

作者： Shanshan Ding Wen Huang Shaogui Yang Danjun Mao Julong Yuan Yuxuan Dai Jijie Kong Cheng Sun Huan He Shiyin Li Limin Zhang State Key Laboratory of Pollution Control and Resource Reuse School of the Environment Nanjing University Nanjing 210023 China school of Environment Nanjing Normal University Nanjing 210023 China

The novel microwave catalyst MgFe204-SiC was synthesized via sol-gel method, to remove azo dye Direct Black BN （DB BN） through adsorption and microwave-induced catalytic reaction. Microwave- induced catalytic degradation of DB BN, including adsorption behavior and its influencing Factors of DB BN on MgFc204-SiC were investigated. According to the obtained results, il indicated thai the pseudo-second-order kinetics model was suitable fbr the adsorption of DB BN onto MgFc204-SiC. Besides, the consequence of adsorption isotherm depicted that the adsorption of DB BN was in accordance with the Langmuir isotherm, which verified that the singer layer adsorption of MgF%O4- SiC was dominant than the multi-layer one. The excellent adsorption capacities of MgFe204-SiC were kept in the range of initial pH from 3 to 7. In addition, it could be concluded that the degradation rate of DB BN decreased over ten percent after the adsorption equilibrium had been attained, and thc results from the result of comparative experiments manitbsted that the adsorption process was not conducive to the process of microwave-induced catalytic degradation. The degradation intermediates and products of DB BN were identified and determined by GC-MS and LC-MS. Furthermore, combined with the catalytic mechanism of MgFe204-SiC, the proposed degradation pathways of DB BN were the involution of microwave-induced OH and holes in this catalytic system the breakage of azo bond, hydroxyl substitution, hydroxyl addition, nitration reaction, dcamination reaction, dcsorbate reaction, dehydroxy group and ring-opening reaction.

关键词： AdsorptionMicrowave-induced catalytic degradationDirect black BNDegradation pathway