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Reinforcing effects of polypropylene on energy absorption and fracturing of cement-based tailings backfill under impact loading

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International Journal of Minerals,Metallurgy and Materials 2024年第4期31卷 650-664页

作者： Jiajian Li Shuai Cao Erol Yilmaz School of Civil and Resources Engineering University of Science and Technology BeijingBeijing 100083China State Key Laboratory of High-Efficient Mining and Safety of Metal Mines of Ministry of Education University of Science and Technology BeijingBeijing 100083China Department of Civil Engineering Geotechnical DivisionRecep Tayyip Erdogan UniversityFenerRize TR53100Turkey

Polypropylene(PP)fiber-reinforced cement-based tailings backfill(FRCTB)is a green compound material with superior crack resistance and has good prospects for application in underground ***,FRCTB exhibits susceptibility to dynamic events,such as impact ground pressure and blast *** paper investigates the energy and crack distribution behavior of FRCTB under dynamic impact,considering the height/diameter(H/D)*** Hopkinson pressure bar,industrial computed tomography scan,and scanning electron microscopy(SEM)experiments were carried out on six types of *** outcomes confirmed fiber aggregation at the bottom of *** H/D was less than 0.8,the proportion of PP fibers distributed along theθangle direction of80°-90°*** the total energy,all samples presented similar energy absorption,reflectance,and ***,a rise in H/D may cause a rise in the energy absorption rate of FRCTB during the peak phase.A positive correlation existed between the average strain rate and absorbed energy per unit *** increase in H/D resulted in a decreased crack volume fraction of *** the H/D was greater than or equal to 0.7,the maximum crack volume fraction of FRCTB was observed close to the incidence *** cracks were present only in the FRCTB with an H/D ratio of *** with H/D ratios of 0.5 and 0.6 showed similar distributions of weakly and heavily damaged *** fibers can limit the emergence and expansion of cracks by influencing their *** observations revealed considerable differences in the bonding strengths between fibers and the *** that adhered particularly well to the substrate were attracted together with the hydration products adhering to *** results show that FRCTB is promising as a sustainable and green backfill for determining the design properties of mining with backfill.

关键词： cement-based tailings fiber-reinforced backfills fracture energy absorption impact loading

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Strong and tough chitin hydrogel constructed by dehydration and rehydration strategy

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Nano Research 2024年第9期17卷 8192-8199页

作者： Rui-Rui Liu Li-Bo Mao Shu-Hong Yu division of Nanomaterials and Chemistry Hefei National Research Center for Physical Sciences at the MicroscaleDepartment of ChemistryInstitute of Biomimetic Materials and ChemistryAnhui Engineering Laboratory of Biomimetic MaterialsUniversity of Science and Technology of ChinaHefei 230026China Institute of Innovative Materials Department of Materials Science and EngineeringDepartment of ChemistrySouthern University of Science and TechnologyShenzhen 518055China

As a renewable,biocompatible,biodegradable soft material,chitin hydrogels have better advantages in stability,antibacterial activity,antifouling,cost,immunogenicity,and so on than most polymer ***,compared with other widely used polymer hydrogels with high strength and toughness,the practical applications of chitin-based hydrogels have been limited by their weak mechanical properties,such as cartilage repair and meniscus ***,we present the design and fabrication of chitin hydrogels with excellent mechanical strength and toughness by a dehydration and rehydration *** sequential dehydration and rehydration processes,the crystalline domains in the chitin hydrogels can be properly *** optimized crystallinity,the elastic modulus of the chitin hydrogels exceeds all previously reported values,and the fracture toughness is even comparable to some synthetic polymer hydrogels,while maintaining a high-water-content of about 80 wt.%.At the same water content,the mechanical properties of the chitin hydrogels are positively correlated with the hydrogel crystallinity,which proves that the change of mechanical properties of hydrogels is not simply dependent on weight *** hydrogels can be further strengthened by incorporating other biopolymers that are intrinsically weak,which makes the hydrogels promising for applications in fields such as cartilage repair and meniscus ***,the hydrogels enable loading and release of water-soluble and poorly water-soluble *** highly extendable strengthening and toughening strategy of chitin and chitin-based biopolymer hydrogels paves the way for their widely applications.

关键词： chitin hydrogel crystallinity rehydration chemical transformation strong and tough

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Sea Keeping Analysis of Air Cushion Vehicle with Different Wave Angles under the Operation Resistance

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Journal of Shanghai Jiaotong university(Science) 2009年第4期14卷 471-475页

作者：周佳唐文勇张圣坤 State Key Laboratory of Ocean Engineering Shanghai Jiaotong University Offshore Engineering & Work Boat design division MARIC-Marine Design & Research Institute of China

The air cushion vehicle (ACV) sea keeping characteristic under different wave directions with the operation resistance is discussed with the couples of the heave, pitch roll motion and the pressure of the cushion. In previous researches, only wave and cross wave direction were discussed. Then a Matlab program is made to calculate the united frequency responses of heave, pitch and roll amplitude of the craft, under different wave frequencies and different wave directions. The results of the research depict some dangerous situations under which the sympathetic vibration happens in heave, pitch and roll motion and the amplitudes are extremely higher than those under the ordinary conditions. These results will be helpful in ACV design and operation.

关键词： air cushion vehicle (ACV) sea keeping characteristic three phase coupling

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VIBRATIONS OF STEPPED RECTANGULAR THIN PLATES ON WINKLER’S FOUNDATION

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Applied Mathematics and Mechanics(English Edition) 1999年第5期20卷 106-116页

作者：张英世 division 508 Department of Flight Vehicle Design and Applied Mechanics Beijing University of Aeronautics and Astronautics Beijing P R China

Differential equations of free/forc ed vibrations of stepped rectangular thin plates on Winkler's foundation are estab lished by using singular functions, and their general solutions are also solved for expression of vibration mode function and frequency equations on usual suppo rts derived with W operator, as well as forced responses of such plates unde r different_type loads disc ussed with Fourier expansion of generalized functions.

关键词： Winkler's foundation stepped rectan gular thin plate free vibration forced response

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VIBRATIONS OF STEPPED ONE-WAY THIN RECTANGULAR PLATES SUBJECTED TO IN-PLANE TENSILE/ COMPRESSIVE FORCE IN Y-DIRECTION ON WINKLER'S FOUNDATION

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Applied Mathematics and Mechanics(English Edition) 2000年第7期21卷 783-790页

作者：张英世 division 508 Department of Flight Vehicle Design and Applied Mechanics Beijing University of Aeronautics and Astronautics Beijing P R China

Differential equations of free/forced vibrations of n_step one_way thin rectangular plates subjected to in_plane tensile/compressive force in y_direction on Winkler's foundation are established by using singular functions, their general solutions solved for, expression of vibration mode function and frequency equation on usual supports derived with W operator. Influence functions for various cases deduced here may also be used to solve problems of static buckling or stability for beams and plates in relevant circumstances.

关键词： rectangular plate free vibration forced vibration response Winkler's foundation subjected to in_plane tensile/compressive force stepped

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Study on gust alleviation control and wind tunnel test

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Science China Technological Sciences 2013年第3期56卷 762-771页

作者： WU ZhiGang CHEN Lei YANG Chao School of Aeronautic Science and Engineering Beijing University of Aeronautics and Astronautics division of Structural Strength Shanghai Aircraft Design and Research Institute

Aircraft are inevitably affected by gust during flight,which disturbs the regular operations of pilots and worsens the ride *** more grievous cases,flight mission cannot be completed and the flight safety may be *** order to improve the ride quality and the fatigue life of the plane structure under the affect of gust,it is necessary to explore and validate the gust alleviation *** the low-speed wind tunnel test,the gust alleviation active control technology applied to elastic aircraft is *** a large-type passenger plane configuration with high aspect ratio wing,a test system was designed and three gust alleviation control schemes with PID controllers were *** the gust alleviation control low-speed wind tunnel test was carried out in the FD-09 wind *** results showed that at certain speed and gust frequency,all of the 3 control schemes can alleviate the acceleration at fuselage and wing-tip to a certain extent,as well as the bending moment of *** gust alleviation control scheme,which uses aileron,elevator and canard as control surfaces synthetically,gives the most satisfying gust alleviation effect.

关键词： aeroelasticity aeroservoelasticity gust response gust alleviation active control wind tunnel test

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Ski jump trajectory with consideration of air resistance

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Journal of Hydrodynamics 2015年第3期27卷 465-468页

作者：吴建华张晓艳马飞吴伟伟 College of Water Conservancy and Hydropower Engineering Hohai University Hydraulic Structure design division Hydrochina Huadong Engineering Corporation

In the case of the ski-jump type energy dissipation, the jet trajectory will be greatly affected by the air entrainment and the air resistance. It is necessary to consider those factors when estimating the trajectory of the jet flow. In this work, the effect of the air resistance on the jet trajectory is theoretically and experimentally investigated. A comprehensive resistance coefficient is proposed. To determine this coefficient, experiments of five models are conducted with the circular-shaped flip bucket placed at the point of the takeoff of ski jumps. It is shown that, this coefficient of the lower jet trajectory is only related to the approach flow Froude number, while that of the upper jet trajectory is dominated by both this Froude number and the deflection angle. Furthermore, the present methodology is validated by experimental data in this work and the maximum errors are not larger than 3.2% and 8.6% for the lower and upper jet trajectories, respectively.

关键词： trajectory jet flow comprehensive resistance coefficient hydropower project

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UNCOVERING BENEFITS AND RISKS OF INTEGRATED PRODUCT SERVICE OFFERINGS-USING A CASE OF TECHNOLOGY ENCAPSULATION

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Journal of Systems Science and Systems Engineering 2013年第4期22卷 421-439页

作者： Tomohiko SAKAO Anna HRWALL RNNBCK Gunilla LUNDH SANDSTRM division of Environmental Technology and Management Department of Management and Engineering division of Industrial Economics Department of Management and EngineeringLinkoping UniversitySweden Unit of Integrated Product Development Department of Machine DesignKTH Royal Institute of TechnologySweden

The objective of this article is to uncover benefits and risks of Integrated Product Service Offering （IPSO） in a systematic manner. To do so, it adopts an explorative longitudinal in-depth case study （development of an IPSO based on a new technology） and adds insights to the existing literature. The article first proposes a theoretical and generic framework termed the PCP （Provider - Customer - Product） triangle with associated information flow and uncertainty. Second, various types of benefits and risks are presented based on the framework. Among others, the benefit of keeping IPR （Intellectual Property Rights） with the provider and the risk of regulation change are new findings from the case study. In addition, the case study reveals that IPSO is regarded as a positive contributor to innovation. Applying the framework and classification of benefits and risks as norms to other cases has yet to be done for verification. However, the framework contributes scientifically to a better understanding of the benefits and risks of IPSO. In addition, this framework is advantageous with its easiness to understand, which contributes practically to the dissemination of IPS0 insight to industry.

关键词： Product/service system (PSS) new technology intellectual property right (IPR) time to market innovation uncertainty

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建筑全生命周期碳排放——内涵、计算和减量

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Engineering 2024年第4期35卷 115-139页

作者： Zujian Huang Hao Zhou Zhijian Miao Hao Tang Borong Lin Weimin Zhuang School of Architecture Tsinghua UniversityBeijing 100084China Key Laboratory of Eco Planning&Green Building Ministry of EducationTsinghua UniversityBeijing 100084China Institute for Urban Governance and Sustainable Development Tsinghua UniversityBeijing 100084China Architectural design and Research Institute of Tsinghua University Beijing 100084China

The life-cycle assessment method,which originates from general products and services,has gradually come to be applied to investigations of the life-cycle carbon emissions(LCCE)of buildings.A literature review was conducted to clarify LCCE implications,calculations,and reductions in the context of buildings.A total of 826 global building carbon emission calculation cases were obtained from 161 studies based on the framework of the building life-cycle stage division stipulated by ISO 21930 and the basic principles of the emission factor(EF)*** carbon emission calculation methods and results are discussed herein,based on the modules of production,construction,use,end-of-life,and supplementary *** to the hotspot distribution of a building’s carbon emissions,carbon reduction strategies are classified into six groups for technical content and benefits analysis,including reducing the activity data pertaining to building materials and energy,reducing the carbon EFs of the building materials and energy,and exploiting the advantages of supplementary *** research gaps and challenges in current building LCCE studies are summarized in terms of research goals and ideas,calculation methods,basic parameters,and carbon reduction strategies;development suggestions are also proposed.

关键词： Building carbon emissions Embodied carbon emissions Operational carbon emissions System boundary Activity data Carbon emission factor Life-cycle assessment Carbon reduction

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Experimental Study and System Identification of Hydrodynamic Force Acting on Heave Damping Plate

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China Ocean Engineering 2008年第1期22卷 141-149页

作者：纪亨腾范菊黄祥鹿 China Ship Development and design Center (Shanghai division) School of Naval Architect Ocean and Civil Engineering Shanghai Jiao Tong University

Although Morison equation is often applied for simulating hydrodynamic force of marine structure, it may give poor results when non-linear behavior is severe or random wave is encountered. This leads to some modifications of Morison equation or other methods for predicting hydrodynamic force. One of them is the system identification technique. In this paper, NARMAX model theory is firstly used to identify the hydrodynamic system of heave damping plates, which are commonly installed on spar platform. Both linear and non-linear models are obtained. The comparisons between the predieted results and measured data indicate that NARMAX model can predict hydrodynamic force of a heave damping plate very well. The measured data for identification originate from forced oscillation tests, which are random records with given spectrum. The forced oscillation forms in experiment also contain simple harmonic, multi-frequency ones.

关键词： heave damping plate Morison equation system identification NARMAX model

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