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Nanoscale deformation of multiaxially forged ultrafine-grained Mg-2Zn-2Gd alloy with high strength-high ductility combination and comparison with the coarse-grained counterpart

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Journal of Materials Science & Technology 2018年第2期34卷 311-316页

作者： k. li V.S.Y.Injeti P. Trivedi L.E. Murr R.D.k. Misra Department of Metallurgical Materials and Biomedical Engineering University of Texas at El Paso 500 W. University Avenue El Paso TX 79968-0521 USA

Cold processing of magnesium （Mg） alloys is a challenge because Mg has a hexagonal close-pack.d （HCP） lattice with limited slip systems, which mak.s it difficult to plastically deform at low temperature. To address this challenge, a combination of annealing of as-cast alloy and multi-axial forging was adopted ro obtain isotropic ultrafine-grained （UFG） structure in a lean Mg-2Zn-2Gd alloy with high strength （yield strength： ~227 MPa）-high ductility （% elongation：～30%） combination. This combination of strength and ductility is excellent for the lean alloy, enabling an understanding of deformation processes in a formable high strength Mg-rare earth alloy. The nanoscale deformation behavior was studied via nanoindentation and electron microscopy, and the behavior was compared with its low strength （yield strength：～46 MPa） - low ductility （% elongation：～7%） coarse-grained （CG） counterpart. In the UFG alloy, extensive dislocation slip was an active deformation mechanism, while in the CG alloy, mechanical twinning occurred. The differences in the deformation mechanisms of UFG and CG alloys were reflected in the discrete burst in the load-displacement plots. The deformation of Mg-2Zn-2Gd alloys was significantly influenced by the grain structure, such that there was change in the deformation mechanism from dislocation slip （non-basal slip） to nanoscale twins in the CG structure. The high plasticity ofUFG Mg alloy involved high dislocation activity and change in activation volume.

关键词： Magnesium alloy Ultrafine-grained Nanoscale deformation

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Two-dimensional materials： Emerging toolk.t for construction of ultrathin high-efficiency microwave shield and absorber

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Frontiers of physics 2018年第4期13卷 53-91页

作者： Mingjun Hu Naibo Zhang Guangcun Shan Jiefeng Gao Jinzhang liu Robert k. Y. li School of Materials Science and Engineering Beihang University Beijing 100191 China Beijing Research and Development Center the 54th Research Institute Electronics Technology Group Corporation Beijing 100070 China School of Instrumentation Science and Opto-electronics Engineering Beihang University Beijing 100191 China School of Chemistry and Chemical Engineering Yangzhou University Yangzhou 225002 China Department of Materials Science and Engineering City University of Hong Kong Hong Kong China

Two-dimensional （2D） materials generally have unusual confined electro-strong interaction in a plane and can physical and chemical properties owing to the exhibit obvious anisotropy and a significant quantum-confinement effect, thus showing great promise in many fields. Some 2D materials, such as graphene and MXenes, have recently exhibited extraordinary electromagnetic-wave shielding and absorbing performance, which is attributed to their special electrical behavior, large specific surface area, and low mass density. Compared with traditional microwave attenuating materials, 2D materials have several obvious inherent advantages. First, similar to other nanomaterials, 2D materials have a very large specific surface area and can provide numerous interfaces for the enhanced interfacial polarization as well as the reflection and scattering of electromagnetic waves. Second, 2D materials have a particular 2D morphology with ultrasmall thick.ess, which is not only beneficial for the penetration and dissipation of electromagnetic waves through the 2D nanosheets, giving rise to multiple reflections and the dissipation of electromagnetic energy, but is also conducive to the design and fabrication of various well-defined structures, such as layer-by-layer assemblies, core-shell particles, and porous foam, for broadband attenuation of electromagnetic waves. Third, owing to their good processability, 2D materials can be integrated into various multifunctional composites for multimode attenuation of electromagnetic energy. In addition to behaving as microwave reflectors and absorbers, 2D materials can act as impedance regulators and provide structural support for good impedance matching and setup of the optimal structure. Numerous studies indicate that 2D materials are among the most promising microwave attenuation materials. In view of the rapid development and enormous advancement of 2D materials in shielding and absorbing electromagnetic wave, there is a strong need to summar

关键词： electromagnetic interference shielding microwave absorber graphene MXenes polymernanocomposites

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Synthesis of 5'-3H-2-Amino-6-cyclopropylaminopurine Nucleosides

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有机化学 2003年第Z1期23卷 35-36页

作者： YANG Zhen-Jun Chung k. Chu ZHANG li-He School of Pharmaceutical Sciences Peking University Health Science Center Beijing 100083 College of Pharmacy The University of Georgia Athens Georgia 30602 College of Pharmacy The University of Georgia Athens Georgia 30602

　　We have described a novel use of the D4G prodrug (Cyclo-D4G) approach to stabilize the nucleoside and maintain the anti-HIV activity. β-D-Dioxolanyl-2-amino-6-cyclopropylaminopurine (10, DACP) was synthesized as a prodrug of β-D-dioxolanyl guanine (DXG) and showed potent anti-HIV activity in vitro (EC50=0.18 μmol·L-1 The pharmacok.netics of Cyclo-D4G and DACP following intravenous and oral administration of DACP to rhesusmonk.ys and rats did not give D4G and DXG as detectable metabolic products by HPLC. Therefore the radio labeled Cyclo-D4G and DACP are necessary for the pharmacok.netics studies in detail.……

关键词： oral administration in vitro

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ECOLOGICAL STUDY OF PICOPLANk.ON IN NORTHERN SOUTH CHINA SEA

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Chinese Journal of Oceanology and limnology 2002年第S1期20卷 22-32页

作者：黄邦钦林学举刘媛戴民汉洪华生 William k. k. li Marine Environmental Lab MOE I Environmental Science Research Center Xiamen University Xiamen 361005 China iological Oceanography Section Bedford Institute of Oceanography Dartmouth Nova Scotia Canada B2Y 4A2

Abundance, carbon biomass and composition of picoplank.on along a transect (fromthe Pearl River estuary to Dongsha Island) in the northern South China Sea were measured by flow cytom-etry (FCM); and the vertical structure, composition variation, relationship between heterotrophic and au-totrophic picoplank.on as well as the controlling mechanism of diel variation were studied. Results showedthat along the horizontal direction, both Synechococcus (SYN) and picoeuk.ryote (PEUk. were highest inabundance and dominated autotrophic picoplank.on in the Pearl River estuary, but decreased

关键词： picoplank.on Synechococcus Prochlarococcus picoeuk.ryote bacteria South China Sea abundance carbon biomass

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Multifunctional organically modified graphene with super-hydrophobicity

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Nano Research 2014年第3期7卷 418-433页

作者： Huawen Hu Chan C. k. Allan Jianhua li Yeeyee k.ng Xiaowen Wang John H. Xin Hong Hu Institute of Textiles and Clothing The Hong Kong Polytechnic University Hong Kong Special Administrative Region (SAR) 999077 China

In order to bring graphene materials much closer to real world applications, it is imperative to have simple, efficient and eco-friendly ways to produce processable graphene derivatives. In this study, a hydrophilic low-temperature thermally functionalized graphene and its super-hydrophobic organically modified graphene derivative were fabricated. A unique structural topology was found and some of the oxygen functionalities were retained on the thermally functionalized graphene surfaces, which facilitated the subsequent highly effective organic modification reaction and led to the super-hydrophobic organically modified graphene with multi functional applications in liquid marbles and polymer nanocomposites. The organic modification reaction also restored the graphenic conjugated structure of the thermally functionalized graphene, particularly for organic modifiers having longer alk.l chains, as confirmed by various characteri- zation techniques such as electrical conductivity measurements, ultraviolet/visible spectroscopy and selected area electron diffraction. The free-standing soft liquid marble was fabricated by wrapping a water droplet with the super-hydrophobic organically modified graphene, and showed potential for use as a microreactor. As for the polymer nanocomposites, a strong interfacial adhesion is believed to exist between an organic polymer matrix and the modified graphene because of the organophilic coating formed on the graphene base, which resulted in large improvements in the thermal and mechanical properties of the polymer nanocomposites with the modified graphene, even at very low loading levels. A new avenue has therefore been opened up for large-scale production of processable graphene derivatives with various practicable applications.

关键词： low-temperature thermallyfunctionalized graphene organic modification organically modifiedgraphene liquid marbles polymer nanocomposites

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Wear Performance of Ultra High Molecular Weight Polyethylene/Quartz Composites

Wear Performance of Ultra High Molecular Weight Polyethylene...

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第三届表面工程国际会议

作者： Chak.in Tang Robert k. Y. li Department of Industrial and Systems Engineering The Hong Kong Polytechnic UniversityKowloonHong KongP. R China Department of Physics and Materials Science City University of Hong KongKowloonHong KongP. R. China

＜正＞ The Ultra high molecular weight polyethylene （UHMWPE） /quartz composites were compression molded in the present of organosiloxane,and then *** used organosiloxane is vinyl tri-ethyloxyl *** gelation,melting behavior,crystallinity,mechanical and wear-resisted properties of the UHMWPE/quartz composites were systematically *** results showed that the organosiloxane acts as a cross-link.ng agent to UHMWPE matrix as well as a coupling aid to interface between quartz and *** 0.5 phr organsiloxane,the wear resistance of the UHMWPE/quartz composites reaches its optimum *** correlation between the properties and morphology of the UHMWPE/quartz composites is discussed.

关键词： UHMWPE/quartz composite organosiloxane cross-link.ng wear-resistance

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Label Recovery and Trajectory Designable Network.for Transfer Fault Diagnosis of Machines With Incorrect Annotation

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 932-945页

作者： Bin Yang Yaguo Lei Xiang li Naipeng li Asok. k.Nandi the k.y Laboratory of Education Ministry for Modern Design and Rotor-Bearing System the School of Mechanical EngineeringXi’an Jiaotong UniveristyXi’an 710049 the Hunan Provincial k.y Labortory of Health Maintenance for Mechanical Equipment Hunan Univeristy of Science and TechnologyXiangtan 411201China the k.y Laboratory of Education Ministry for Modern Design and Rotor-Bearing System Xi’an Jiaotong UniveristyXi’an 710049China the Department of Electronic and Electrical Engineering Brunel University LondonUxbridge UB83PHUK

The success of deep transfer learning in fault diagnosis is attributed to the collection of high-quality labeled data from the source ***,in engineering scenarios,achieving such high-quality label annotation is difficult and *** incorrect label annotation produces two negative effects:1)the complex decision boundary of diagnosis models lowers the generalization performance on the target domain,and2)the distribution of target domain samples becomes misaligned with the false-labeled *** overcome these negative effects,this article proposes a solution called the label recovery and trajectory designable network.LRTDN).LRTDN consists of three ***,a residual network.with dual classifiers is to learn features from cross-domain ***,an annotation check.module is constructed to generate a label anomaly indicator that could modify the abnormal labels of false-labeled samples in the source *** the training of relabeled samples,the complexity of diagnosis model is reduced via semi-supervised ***,the adaptation trajectories are designed for sample distributions across *** ensures that the target domain samples are only adapted with the pure-labeled *** LRTDN is verified by two case studies,in which the diagnosis k.owledge of bearings is transferred across different work.ng conditions as well as different yet related *** results show that LRTDN offers a high diagnosis accuracy even in the presence of incorrect annotation.

关键词： Deep transfer learning domain adaptation incorrect label annotation intelligent fault diagnosis rotating machines

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A Tutorial to Approximately Invert the Sumudu Transform

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Applied Mathematics 2019年第11期10卷 1004-1028页

作者： Glen Atlas John k.-J. li Adam Work Department of Anesthesiology Rutgers New Jersey Medical School Newark NJ USA Department of Biomedical Engineering Stevens Institute of Technology Hoboken NJ USA Department of Biomedical Engineering Rutgers University Piscataway NJ USA

Unlik. the traditional Laplace transform, the Sumudu transform of a function, when approximated as a power series, may be readily inverted using factorial-based coefficient diminution. This technique offers straightforward computational advantages for approximate range-limited numerical solutions of certain ordinary, mixed, and partial linear differential and integro-differential equations. Furthermore, discrete convolution (the Cauchy product), may also be utilized to assist in this approximate inversion method of the Sumudu transform. Illustrative examples are provided which elucidate both the applicability and limitations of this method.

关键词： Sumudu Transform Double Series Discrete Convolution Cauchy Product

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Reactive oxygen species promote endurance exercise-induced adaptations in sk.letal muscles

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Journal of Sport and Health Science 2024年第6期13卷 780-792页

作者： Scott k.Powers Zsolt Radak.li li Ji Malcolm Jack.on Department of Applied Physiology University of FloridaGainesvilleFL 32608USA Research Institute of Sport Science Hungarian University of Sport ScienceBudapest 1123Hungary Department of k.nesiology University of MinnesotaSt.PaulMN 55455USA Department of Musculosk.letal and Ageing Science Institute of Life Course and Medical SciencesUniversity of LiverpoolLiverpool L78TXUK

The discovery that contracting sk.letal muscle generates reactive oxygen species(ROS)was first reported over 40 years *** prevailing view in the 1980s was that exercise-induced ROS production promotes oxidation of proteins and lipids resulting in muscle ***,a paradigm shift occurred in the 1990s as growing research revealed that ROS are signaling molecules,capable of activating transcriptional activators/coactivators and promoting exercise-induced muscle *** evidence supports the notion that reduction-oxidation(redox)signaling pathways play an important role in the muscle remodeling that occurs in response to endurance exercise *** review examines the specific role that redox signaling plays in this endurance exercise-induced sk.letal muscle *** begin with a discussion of the primary sites of ROS production in contracting muscle fibers followed by a summary of the antioxidant enzymes involved in the regulation of ROS levels in the *** then discuss which redox-sensitive signaling pathways promote endurance exercise-induced muscle adaptation and debate the strength of the evidence supporting the notion that redox signaling plays an essential role in muscle adaptation to endurance exercise *** hopes of stimulating future research,we highlight several important unanswered questions in this field.

关键词： Antioxidants Mitochondrial biogenesis Radicals Redox signaling

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ERAD: Enhanced Ransomware Attack.Defense System for Healthcare Organizations

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Journal of Software Engineering and Applications 2024年第5期17卷 270-296页

作者： Xinyue li Vijay k. Madisetti School of Cybersecurity and Privacy Georgia Institute of Technology Atlanta Georgia USA

Digital integration within healthcare systems exacerbates their vulnerability to sophisticated ransomware threats, leading to severe operational disruptions and data breaches. Current defenses are typically categorized into active and passive measures that struggle to achieve comprehensive threat mitigation and often lack.real-time response effectiveness. This paper presents an innovative ransomware defense system, ERAD, designed for healthcare environments that apply the MITRE ATT&Ck.Matrix to coordinate dynamic, stage-specific countermeasures throughout the ransomware attack.lifecycle. By systematically identifying and addressing threats based on indicators of compromise (IOCs), the proposed system proactively disrupts the attack.chain before serious damage occurs. Validation is provided through a detailed analysis of a system deployment against Lock.it 3.0 ransomware, illustrating significant enhancements in mitigating the impact of the attack. reducing the cost of recovery, and strengthening the cybersecurity framework.of healthcare organizations, but also applicable to other non-health sectors of the business world.

关键词： Ransomware Healthcare Cybersecurity MITRE ATT&Ck.Matrix Incident Response Ransomware Attack.lifecycle Digital Health Safety

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