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Blast waveform tailoring using controlled venting in blast simulators and shock tubes

Defence Technology（防务技术） 2024年第7期37卷 14-26页

作者： Edward chern Jinn Gan Alex Remennikov David Ritzel Faculty of Engineering and Information sciences University of WollongongWollongongNSW2522Australia Dyn-FX Consulting Ltd 19 Laird Ave NorthAmherstburgONN9V 2T5Canada

A critical challenge of any blast simulation facility is in producing the widest possible pressure-impulse range for matching against equivalent high-explosive *** tubes and blast simulators are often constrained with the lack of effective ways to control blast wave profiles and as a result have a limited performance *** wave shaping techniques employed in some facilities are reviewed but often necessitate extensive geometric modifications,inadvertently cause flow anomalies,and/or are only applicable under very specific *** paper investigates controlled venting as an expedient way for waveforms to be tuned without requiring extensive modifications to the driver or existing geometry and could be widely applied by existing and future blast simulation and shock tube *** use of controlled venting is demonstrated experimentally using the Advanced Blast simulator(shock tube)at the Australian National Facility of Physical Blast simulation and via numerical flow simulations with Computational Fluid *** venting is determined as an effective method for mitigating the impact of re-reflected waves within the blast *** control method also allows for the adjustment of parameters such as tuning the peak overpressure,the positive phase duration,and modifying the magnitude of the negative phase and the secondary shock of the blast *** paper is concluded with an illustration of the potential expanded performance range of the Australian blast simulation facility when controlled venting for blast waveform tailoring as presented in this paper is applied.

关键词： Advanced blast simulator shock wave propagation Far-field explosion Blast loads Blast waves Computational fluid dynamics

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Data-Driven Learning Control Algorithms for Unachievable Tracking Problems

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IEEE/CAA Journal of Automatica sinica 2024年第1期11卷 205-218页

作者： Zeyi Zhang Hao Jiang Dong shen samer s.saab the school of Mathematics Renmin University of ChinaBeijing 100872China IEEE the school of Engineering Lebanese American UniversityByblos 2038Lebanon

For unachievable tracking problems, where the system output cannot precisely track a given reference, achieving the best possible approximation for the reference trajectory becomes the objective. This study aims to investigate solutions using the Ptype learning control scheme. Initially, we demonstrate the necessity of gradient information for achieving the best ***, we propose an input-output-driven learning gain design to handle the imprecise gradients of a class of uncertain systems. However, it is discovered that the desired performance may not be attainable when faced with incomplete *** address this issue, an extended iterative learning control scheme is introduced. In this scheme, the tracking errors are modified through output data sampling, which incorporates lowmemory footprints and offers flexibility in learning gain *** input sequence is shown to converge towards the desired input, resulting in an output that is closest to the given reference in the least square sense. Numerical simulations are provided to validate the theoretical findings.

关键词： Data-driven algorithms incomplete information iterative learning control gradient information unachievable problems

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Large reversible magnetocaloric effect in antiferromagnetic Er_(3)si_(2)C_(2) compound

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Journal of Rare Earths 2024年第8期42卷 1555-1559,I0005页

作者： Hao sun Lu Tian Xinqiang Gao Zhaojun Mo Jun shen Baogen shen school of Rare Earths University of Science and Technology of ChinaHefei230026China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou341000China Department of Energy and Power Engineering School of Mechanical EngineeringBeijing Institute of TechnologyBeijing100081China

The magnetic properties,magnetic phase transition and magnetocaloric effects(MCE) of Er_(3)si_(2)C_(2) compound were investigated based on theoretical calculations and experimental *** on the first principles calculations,the antiferromagnetic(AFM) ground state type in Er_(3)si_(2)C_(2) compound was predicted and its electronic structure was *** experimental results show that Ei_(3)si_(2)C_(2) compound is an AFM compound with the Neel temperature(T_(N) of 7 K and undergoes a field-induced firstorder magnetic phase transition from AFM to ferromagnetic(FM) under magnetic fields exceeding 0.6 T at 2 *** magnetic transition process of Er_(3)si_(2)C_(2) compound was investigated and *** values of the maximum magnetic entropy change(-Δs_(M)^(max)) and the refrigeration capacity(RC) are 17 J/(kg·K)and 193 J/kg under changing magnetic fields of 0-5 T,*** a potential cryogenic magnetic refrigerant,the Er_(3)si_(2)C_(2) compound also provides an interesting research medium to study the magnetic phase transition process.

关键词： Magnetic materials Magnetocaloric Metamagnetic transitions Magnetic phase transition Rare earths

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on the half-quantized Hall conductance of massive surface electrons in magnetic topological insulator films

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science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 127-136页

作者： Rui Chen shun-Qing shen Department of Physics The University of Hong KongHong Kong 999077China Department of Physics Hubei UniversityWuhan 430062China

In topological insulators,massive surface states resulting from local symmetry breaking were thought to exhibit a half-quantized Hall conductance,obtained from the low-energy effective model in an infinite Brillouin *** a lattice model,the surface band is composed of a combination of surface states and bulk *** massive surface states alone may not be enough to support an exact one-half quantized surface Hall conductance in a finite Brillouin zone and the whole surface band always gives an integer quantized Hall conductance as enforced by the TKNN *** explore this,we investigate the band structures of a lattice model describing the magnetic topological insulator film that supports the axion insulator,chern insulator,and semi-magnetic topological insulator *** reveal that the gapped and gapless surface bands in the three phases are characterized by an integer-quantized Hall conductance and a half-quantized Hall conductance,*** propose an effective model to describe the three phases and show that the low-energy dispersion of the surface bands inherits from the surface Dirac *** gapped surface band manifests a nearly half-quantized Hall conductance at low energy near the center of Brillouin zone,but is compensated by another nearly half-quantized Hall conductance at high energy near the boundary of Brillouin zone because a single band can only have an integer-quantized Hall *** gapless band hosts a zero Hall conductance at low energy but is compensated by another half-quantized Hall conductance at high energy,and thus the half-quantized Hall conductance can only originate from the gapless ***,we calculate the layer-resolved Hall conductance of the *** conclusion suggests that the individual gapped surface band alone does not support the half-quantized surface Hall effect in a lattice model.

关键词： magnetic topological insulator Dirac equation half-quantized Hall conductance

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Comprehensive strategic Planning and Enhancement of China CDC Contributes to High-Quality Development of the National Disease Control and Prevention system

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China CDC weekly 2024年第4期6卷 61-63页

作者： Hongbing shen Director-General of China CDC Academician of the Chinese Academy of EngineeringBeijingChina

The Chinese government has always attached great importance to disease control and prevention ***,the general office of China’s state Council issued the“Guidelines for High-Quality Development of Disease Prevention and Control”(hereinafter referred to as the“Guidelines”)(1).The Guidelines focus on promoting high-quality development of disease control and prevention and the strategic goal of“Healthy China,”providing specific implementation pathways for the development of national disease control and prevention in the new era,including overall planning,restructuring of governance,enhancing core capabilities,strengthening talent development,and improving organizational support.

关键词： prevention attached Quality

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Wireless multisite sensing systems for continuous physiological monitoring

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science China Materials 2024年第6期67卷 2045-2047页

作者： Ruilai Wei Qilin Hua Guozhen shen school of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijing 100081China Institute of Flexible Electronics Beijing Institute of TechnologyBeijing 102488China

Respiratory diseases rank as the third leading cause of adult mortality[1],while cardiopulmonary and gastrointestinal issues are the primary cause of death within the first five years of a child’s life[2].The monitoring of cardiac,respiratory,and gastrointestinal sounds plays a vital role in routine care,as alterations or absence of these body sounds can serve as indicators of underlying diseases.

关键词： routine continuous monitoring

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A systematic Analysis of Early Life Exposure to the Chinese Famine(1959-1961)and the Health of older Adults-China,2008-2023

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China CDC weekly 2024年第11期6卷 203-207,I0001-I0003页

作者： Chi shen Xi Chen school of Public Policy and Administration Xi’an Jiaotong UniversityXi’an CityShaanxi ProvinceChina Department of Health Policy and Management Yale School of Public HealthNew HavenCTU.S Department of Economics Yale UniversityNew HavenCTU.S

What is already known about this topic?There is mounting evidence indicating that the aging process initiates during early life stages,with in utero the individual’s environment playing a significant ***,it is crucial to comprehend the enduring effects of early life circumstances on health in old *** is added by this report?In this study,we conducted a meta-analysis to examine the effects of the Chinese Famine(1959–1961)on the health of older *** also explored potential mechanisms underlying these *** are the implications for public health practice?The complex interplay between early life circumstances,multiple health-related sectors,and healthy aging necessitates a comprehensive life-course approach and strategic interventions to enhance public health in an aging society.

关键词： life aging mount

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Novel Adaptive Memory Event-Triggered-Based Fuzzy Robust Control for Nonlinear Networked systems via the Differential Evolution Algorithm

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IEEE/CAA Journal of Automatica sinica 2024年第8期11卷 1836-1848页

作者： Wei Qian Yanmin Wu Bo shen school of Electrical Engineering and Automation Henan Polytechnic UniversityJiaozuo 454000China College of Information science and Technology Donghua UniversityShanghai 201620China

This article mainly investigates the fuzzy optimization robust control issue for nonlinear networked systems characterized by the interval type-2(IT2)fuzzy technique under a differential evolution *** provide a more reasonable utilization of the constrained communication channel,a novel adaptive memory event-triggered(AMET)mechanism is developed,where two event-triggered thresholds can be dynamically adjusted in the light of the current system information and the transmitted historical *** conditions with less conservative design of the fuzzy imperfect premise matching(IPM)controller are presented by introducing the Wirtinger-based integral inequality,the information of membership functions(MFs)and slack ***,under the IPM policy,a new MFs intelligent optimization technique that takes advantage of the differential evolution algorithm is first provided for IT2 Takagisugeno(T-s)fuzzy systems to update the fuzzy controller MFs in real-time and achieve a better system control ***,simulation results demonstrate that the proposed control scheme can obtain better system performance in the case of using fewer communication resources.

关键词： Adaptive memory event-triggered(AMET) differential evolution algorithm fuzzy optimization robust control interval type-2(IT2)fuzzy technique.

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Theory and classification of mass extinction causation

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National science Review 2024年第1期11卷 16-36页

作者： Thomas J.Algeo Jun shen state Key Laboratory of Biogeology and Environmental Geology China University of Geosciences—Wuhan state Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences—Wuhan Department of Geosciences University of Cincinnati

Theory regarding the causation of mass extinctions is in need of systematization, which is the focus of this contribution. Every mass extinction has both an ultimate cause, i.e. the trigger that leads to various climato-environmental changes, and one or more proximate cause(s), i.e. the specific climato-environmental changes that result in elevated biotic mortality. With regard to ultimate causes, strong cases can be made that bolide(i.e. meteor) impacts, large igneous province(LIP) eruptions and bioevolutionary events have each triggered one or more of the Phanerozoic Big Five mass extinctions, and that tectono-oceanic changes have triggered some second-order extinction events. Apart from bolide impacts, other astronomical triggers(*** flares, gamma bursts and supernova explosions) remain entirely in the realm of speculation. With regard to proximate mechanisms, most extinctions are related to either carbon-release or carbon-burial processes, the former being associated with climatic warming, ocean acidification, reduced marine productivity and lower carbonate δ13C values, and the latter with climatic cooling, increased marine productivity and higher carbonate δ13C values. Environmental parameters such as marine redox conditions and terrestrial weathering intensity do not show consistent relationships with carbon-cycle *** this context, mass extinction causation can be usefully classified using a matrix of ultimate and proximate factors. Among the Big Five mass extinctions, the end-Cretaceous biocrisis is an example of a bolide-triggered carbon-release event, the end-Permian and end-Triassic biocrises are examples of LIP-triggered carbon-release events, and the Late ordovician and Late Devonian biocrises are examples of bioevolution-triggered carbon-burial events. Whereas the bolide-impact and LIP-eruption mechanisms appear to invariably cause carbon release, bioevolutionary triggers can result in variable carbon-cycle changes, e.g. carbon burial durin

关键词： biocrisis ultimate cause proximate cause bolide large igneous province bioevolutionary event

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Impact of High sodium Diet on Neovascularization and osseointegration around Titanium Implant:An in Vivo and in Vitro study

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Biomedical and Environmental sciences 2024年第7期37卷 739-753页

作者： Keyuan Xu Xiaoting Tang Yun Xiang Yiding shen Zhennan Deng Pingping Ma Xinkun shen Department of orthopaedics The Third Affiliated Hospital of Wenzhou Medical University(Ruian People’s Hospital)Wenzhou 325016ZhejiangChina school and Hospital of stomatology Wenzhou Medical UniversityWenzhou 325027ZhejiangChina

objective A high sodium(Hs)diet is believed to affect bone metabolism *** its impact on osseointegration of titanium(Ti)implants holds significant implications for postoperative dietary management of implanted *** This investigation probed the impact of sodium ions(Na^(+))on neovascularization and osteogenesis around Ti implants in vivo,utilizing micro-computed tomography,hematoxylin and eosin staining,and immunohistochemical ***,in vitro experiments assessed the effects of varied Na^(+)concentrations and exposure durations on human umbilical vein endothelial cells(HUVECs)and MC3T3-E1 *** In vivo,increased dietary sodium(0.8%-6.0%)led to a substantial decline in CD34 positive HUVECs and new bone formation around Ti implants,alongside an increase in inflammatory *** vitro,an increase in Na^(+)concentration(140-150 mmol/L)adversely affected the proliferation,angiogenesis,and migration of HUVECs,especially with prolonged *** MC3T3-E1 cells initially exhibited less susceptibility to high Na^(+)concentrations compared to HUVECs during short-term exposure,prolonged exposure to a Hs environment progressively diminished their proliferation,differentiation,and osteogenic *** These findings suggest that Hs diet had a negative effect on the early osseointegration of Ti implants by interfering with the process of postoperative vascularized bone regeneration.

关键词： High-sodium Implants Vascularization osseointegration

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