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Long-Term Performance and Microstructural Characterization of Dam Concrete in the Three Gorges Project
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作者 Chen Lyu Cheng Yu +3 位作者 Chao Lu Li Pan Wenwei Li Jiaping Liu 《Engineering》 SCIE EI CAS CSCD 2024年第2期237-262,共26页
This study investigates the long-term performance of laboratory dam concrete in different curing environments over ten years and the microstructure of 17-year-old laboratory concrete and actual concrete cores drilled ... This study investigates the long-term performance of laboratory dam concrete in different curing environments over ten years and the microstructure of 17-year-old laboratory concrete and actual concrete cores drilled from the Three Gorges Dam.The mechanical properties of the laboratory dam concrete,whether cured in natural or standard environments,continued to improve over time.Furthermore,the laboratory dam concrete exhibited good resistance to diffusion and a refined microstructure after 17 years.However,curing and long-term exposure to the local natural environment reduced the frost resistance.Microstructural analyses of the laboratory concrete samples demonstrated that moderate-heat cement and fine fly ash(FA)particles were almost fully hydrated to form compact micro structures consisting of large quantities of homogeneous calcium(alumino)silicate hydrate(C-(A)-S-H)gels and a few crystals.No obvious interfacial transition zones were observed in the microstructure owing to the longterm pozzolanic reaction.This dense and homogenous microstructure was the crucial reason for the excellent long-term performance of the dam concrete.A high FA volume also played a significant role in the microstructural densification and performance growth of dam concrete at a later age.The concrete drilled from the dam surface exhibited a loose microstructure with higher microporosity,indicating that concrete directly exposed to the actual service environment suffered degradation caused by water and wind attacks.In this study,both macro-performance and microstructural analyses revealed that the application of moderate-heat cement and FA resulted in a dense and homogenous microstructure,which ensured the excellent long-term performance of concrete from the Three Gorges Dam after 17 years.Long-term exposure to an actual service environment may lead to microstructural degradation of the concrete surface.Therefore,the retained long-term dam concrete samples need to be further researched to better understand its microstructural evolution and development of its properties. 展开更多
关键词 Three Gorges Dam long-term performance Microstructural analysis Moderate-heat cement Fly ash
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Long-term performance of recycled asphalt mixtures containing high RAP and RAS
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作者 Jiangmiao Yu Zengyao Lin +3 位作者 Guilian Zou Huayang Yu Zhen Leng Yuan Zhang 《Journal of Road Engineering》 2024年第1期36-53,共18页
The application of reclaimed asphalt pavement(RAP)and reclaimed asphalt shingles(RAS)on asphalt pavement can reduce the asphalt paving cost,conserve energy and protect the environment.However,the use of high contents ... The application of reclaimed asphalt pavement(RAP)and reclaimed asphalt shingles(RAS)on asphalt pavement can reduce the asphalt paving cost,conserve energy and protect the environment.However,the use of high contents of RAP and RAS in asphalt pavement may lead to durability issues,especially the fatigue cracking and thermal cracking.It is necessary to conduct a series of analyses on asphalt mixtures containing high RAP and RAS,and seek methods to enhance their long-term performance.This paper provides a comprehensive over-view of the long-term performance of recycled asphalt mixtures containing high contents of RAP and RAS.The findings in this research show that rutting resistance of high recycled asphalt mixtures is not a concern,whereas their resistance to fatigue and thermal cracking is not conclusive.Recycling agents can be used to improve the thermal cracking resistance of high recycled asphalt mixtures.An optimum decision on recycling agents will improve the durability properties of high recycled asphalt mixtures.It is recommended that to use a balanced mixture design approach with testing of the blended asphalt binders will provide better understanding of long-term performance of recycled asphalt mixtures containing high RAP and RAS. 展开更多
关键词 Recycled asphalt mixture Recycling agents long-term performance CRACKING
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Improving the sintering performance of blends containing Canadian specularite concentrate by modifying the binding medium 被引量:5
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作者 Feng Zhang De-qing Zhu +2 位作者 Jian Pan Ya-ping Mo Zheng-qi Guo 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2018年第6期598-608,共11页
Canadian specularite concentrate(CSC) possesses high total iron grade and low impurity content. However, due to the poor granulating performance and weak reactivity of CSC at high temperature, the proportion of CSC ... Canadian specularite concentrate(CSC) possesses high total iron grade and low impurity content. However, due to the poor granulating performance and weak reactivity of CSC at high temperature, the proportion of CSC used in sintering blends is restricted. In this research, the effects of fine limonite, slake lime, and bentonite particles on the granulation performance of blends containing a high ratio of CSC were studied through granulation test. Based on the test results, the effects of modification of the binding medium on the sintering performance of blends containing a high ratio of CSC were revealed by the sintering pot test. Both the granulation property and sintering performance of blends with a high proportion of CSC were improved by modifying the binding medium. 展开更多
关键词 iron ore binding medium specula^ite CONCENTRATE sintering performance
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Dimensionality regulation in tin halide perovskite solar cells: Toward high performance and stability
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作者 Huanhuan Yao Shurong Wang +2 位作者 Zhiwen Jin Liming Ding Feng Hao 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第2期144-156,I0005,共14页
Tin halide perovskites(THPs)have received extensive attention due to their low toxicity and excellent optoelectronic properties,and are considered to be the most promising alternatives to develop efficient lead-free p... Tin halide perovskites(THPs)have received extensive attention due to their low toxicity and excellent optoelectronic properties,and are considered to be the most promising alternatives to develop efficient lead-free perovskite solar cells.However,due to the unique and inherent characteristics of Sn^(2+)being easily oxidized to Sn^(4+)and fast crystallization,tin perovskite solar cells(TPSCs)show relatively poor performance and stability,compared to the lead counterparts.Recently,the introduction of bulky organic spacers into three-dimensional(3D)THPs for dimensional regulation can not only prevent the intrusion of water and oxygen,but also inhibit the self-doping effect and ion migration.In this review,we will detail how dimensional regulation enables TPSCs with high performance and superior stability.First,we summarize the intrinsic properties of THPs and analyze the root causes of their poor performance and instability.Next,we discuss the specific structure and types of the dimensional regulation strategy.Then,the mechanism of dimensional regulation is discussed in detail,mainly from inhibiting the Sn^(2+)oxidation,optimizing crystallization,passivating defects,and improving energy level alignment.Finally,future challenges and prospects for dimensional regulation are elaborated to help researchers develop more efficient and stable TPSCs. 展开更多
关键词 Organic spacers Dimensional regulation long-term stability performance Photovoltaics
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Energy and long-term hygrothermal performance of building enclosures based on dynamic environmental simulation test 被引量:1
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作者 Shi Xing 《Engineering Sciences》 EI 2010年第1期92-96,共5页
Dynamic environmental testing is an effective means to study the energy and long-term hygrothermal performance of building enclosures. Southeast University is designing and building a large-scale dynamic environment s... Dynamic environmental testing is an effective means to study the energy and long-term hygrothermal performance of building enclosures. Southeast University is designing and building a large-scale dynamic environment simulation testing facility. It can simuhaneously and dynamically simulate temperature, relative humidity, infrared solar radiation, UV radiation, and precipitation. A transformation is needed to predict the energy and long-term hygrothermal performance of building enclosures under real service conditions using data obtained from accelerated tests. 展开更多
关键词 environmental simulation hygrothermal performance long-term performance heat box environmental acceleration
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Technical development and long-term performance observations of long-life asphalt pavement: A case study of Shandong Province 被引量:4
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作者 Lin Wang Jincheng Wei +3 位作者 Wenjuan Wu Xiaomeng Zhang Xizhong Xu Xiangpeng Yan 《Journal of Road Engineering》 2022年第4期369-389,共21页
Based on the investigation of long-life asphalt pavement at home and abroad,the development of long-life asphalt pavement technology in Shandong Province,China is reviewed in this paper.The structural combination char... Based on the investigation of long-life asphalt pavement at home and abroad,the development of long-life asphalt pavement technology in Shandong Province,China is reviewed in this paper.The structural combination char-acteristics of typical long-life asphalt pavement in Shandong Province and their popularization and application are introduced.The application effect of combined base long-life asphalt pavement,which has been widely promoted,is evaluated.At the same time,taking the Binda perpetual pavement test road in Shandong Province as an example,the dynamic response and long-term performance evolution of long-life asphalt pavement are analyzed over a period of more than 17 years.Sections S1,S2,and S3 present information about full-depth asphalt pavement.Section S4 describes combined base asphalt pavement.The results show that the maximum strain of S1–S4 is within the endurance strain limit.S1,S2,S3 and S4 are all expected to be long-life asphalt pavements.In the current study,Sections S1–S4 were maintained in good condition during a service period of more than 17 years with no structural cracks and good deflection,rutting,and IRI indexes.The deflection index was stable without growth,and the IRI was also relatively stable following the opening to traffic.The rutting depth un-derwent a slight cumulative increase within 8 years of opening,and then stabilized.The average rutting depth over the 17-year period was less than 15 mm.Therefore,S1–S4 meet the design standards required for use as long-life pavements.From the perspectives of resource saving,energy saving,and emission reduction and service performance,full-depth asphalt pavement can be considered to represent a new generation of green and durable pavement structures with great future promotion potential. 展开更多
关键词 Long-life asphalt pavement Dynamic response STRAIN DEFLECTION long-term performance
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Long-term Performance of Moderate Heat Portland Cement with Double-expansive Sources
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作者 叶青 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2007年第1期35-39,共5页
The long-term performance of moderate heat Portland cement with double-expansive sources (DE cement) in the system of high MgO clinker and gypsum was studied by XRD, SEM/EDAX and test methods for strength and expans... The long-term performance of moderate heat Portland cement with double-expansive sources (DE cement) in the system of high MgO clinker and gypsum was studied by XRD, SEM/EDAX and test methods for strength and expansion of cement. Results indicate that the periclase particle, whose size was 5-7.5μm in DE cement clinker containing 4.8 % MgO, existed individually. The periclase hydration in hardened DE cement paste started at about 60 days and completed up to 2 000 days, and ettringite in the paste was stable from 3 days to 2 000 days. Under the conditions of 4.5%-5.0 % MgO in clinker and 2.8%-3.4 %SO3 in cement, ettringite expansion and brucite expansion in DE cement paste had a continuity, entirety and stability. At the ages of 90, 365,730 and 2 000 days the expansion of the paste reached 0.07%-0.11%, 0.16%-0.21%, 0.21%-0.27 %, and 0.29%-0.38%, respectively. The results suggest that by using this cement in mass concrete it may compensate its temperature shrinkage and autogenous shrinkage to some extent. 展开更多
关键词 BRUCITE ETTRINGITE EXPANSION long-term performance moderate heat Portland cement
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Curling of New Concrete Pavement and Long-Term Performance
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作者 Daba S. Gedafa M. Hossain +2 位作者 Z. Q. Siddique K. Fredrichs D. Meggers 《Journal of Civil Engineering and Architecture》 2012年第2期121-130,共10页
Curling results from the temperature differential across the concrete slab thickness and may induce undue stresses in newly placed slab. This study deals with the finite element (FE) analysis of curling, curling str... Curling results from the temperature differential across the concrete slab thickness and may induce undue stresses in newly placed slab. This study deals with the finite element (FE) analysis of curling, curling stresses, field measurement of curling on a newly built jointed plain concrete pavement, and comparison of its long-term performance using both Mechanistic-Empirical Pavement Design Guide (MEPDG) and HIPERPAVII software. The FE analysis was performed with a software program, ANSYS. The test section was modeled as a three-layer system with 300 mm concrete slab, 100 mm treated drainable base, and 150 mm lime-treated subgrade. All layers were assumed to be linear elastic. Temperature data was collected at five different depth locations across the concrete slab with digital data loggers. Curling was measured on five different days with a simple setup. The effect of temperature nonlinearities across the slab thickness was also examined. The results show that both upward and downward curling increase as the temperature differential increases. The maximum stress resulting from the combined effect of curling and traffic loading due to positive temperature differential is higher than that due to the negative temperature differential of the same magnitude. Since temperature differential has a significant influence on curling, both curling and curling stresses can be mitigated at an early age with temperature control, namely via enhanced curing. Both MEPDG and HIPERPAVII showed approximately the same performance for the PCC thickness ranging from 215 mm to 300 mm for this project. Performance prediction from HIPERPAVII is very sensitive to the change in PCC thickness less than 230 mm whereas MEPDG prediction is not as sensitive to the thickness change as with HIPERPAV 1I. 展开更多
关键词 CURLING HIPERPAVII long-term performance MEPDG.
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PERFORMANCE-DRIVEN BUSINESS PROCESS MANAGEMENT METHODOLOGY FOR SMALL AND MEDIUM SIZED-ENTERPRISES
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作者 TangHongtao TangRenzhong 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2004年第4期565-570,共6页
Based on the analysis of the common limitations of business processmanagement (BPM) methodologies and the requirements of small and medium sized-enterprises (SMEs),the importance of a 'performance construct' o... Based on the analysis of the common limitations of business processmanagement (BPM) methodologies and the requirements of small and medium sized-enterprises (SMEs),the importance of a 'performance construct' of BPM methodologies is identified, a six-phaseperformance-driven BPM methodology for the production and operation processes of Chinese SMEs isdeveloped. A case study on the process management of a medium-sized enterprise shows a successfulexample of running the methodology. 展开更多
关键词 Business process management Process management methodology Processperformance performance-driven Small and medium sized-enterprises
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Full-scale multi-functional test platform for investigating mechanical performance of track–subgrade systems of high-speed railways 被引量:2
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作者 Wanming Zhai Kaiyun Wang +3 位作者 Zhaowei Chen Shengyang Zhu Chengbiao Cai Gang Liu 《Railway Engineering Science》 2020年第3期213-231,共19页
Motivated by the huge practical engineering demand for the fundamental understanding of mechanical characteristics of high-speed railway infrastructure,a fullscale multi-functional test platform for high-speed railway... Motivated by the huge practical engineering demand for the fundamental understanding of mechanical characteristics of high-speed railway infrastructure,a fullscale multi-functional test platform for high-speed railway track–subgrade system is developed in this paper,and its main functions for investigating the mechanical performance of track–subgrade systems are elaborated with three typical experimental examples.Comprising the full-scale subgrade structure and all the five types of track structures adopted in Chinese high-speed railways,namely the CRTS I,the CRTS II and the CRTS III ballastless tracks,the double-block ballastless track and the ballasted track,the test platform is established strictly according to the construction standard of Chinese high-speed railways.Three kinds of effective loading methods are employed,including the real bogie loading,multi-point loading and the impact loading.Various types of sensors are adopted in different components of the five types of track–subgrade systems to measure the displacement,acceleration,pressure,structural strain and deformation,etc.Utilizing this test platform,both dynamic characteristics and long-term performance evolution of high-speed railway track–subgrade systems can be investigated,being able to satisfy the actual demand for large-scale operation of Chinese high-speed railways.As examples,three typical experimental studies are presented to elucidate the comprehensive functionalities of the full-scale multi-functional test platform for exploring the dynamic performance and its long-term evolution of ballastless track systems and for studying the long-term accumulative settlement of the ballasted track–subgrade system in high-speed railways.Some interesting phenomena and meaningful results are captured by the developed test platform,which provide a useful guidance for the scientific operation and maintenance of high-speed railway infrastructure. 展开更多
关键词 Full-scale test High-speed railway Track–subgrade system Ballastless track Ballasted track Mechanical performance long-term performance evolution Damage and degradation
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Mechanisms by which fibroblast growth factor 20 improves motor performance in a mouse model of Parkinson’s disease 被引量:1
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作者 Ai-Qin Wang Li-Na Kong +3 位作者 Ming-Zhu Meng Xiu-He Zhao Si Chen Xiao-Tang Wang 《Neural Regeneration Research》 SCIE CAS CSCD 2019年第8期1438-1444,共7页
Genome-wide studies have reported that Parkinson’s disease is associated with abnormal expression of various growth factors. In this study, male C57 BL/6 mice aged 10 weeks were used to establish Parkinson’s disease... Genome-wide studies have reported that Parkinson’s disease is associated with abnormal expression of various growth factors. In this study, male C57 BL/6 mice aged 10 weeks were used to establish Parkinson’s disease models using an intraperitoneal injection of 60 mg/kg 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. 28 days later, 10 or 100 ng fibroblast growth factor 20 was injected intracerebroventricularly. The electrophysiological changes in the mouse hippocampus were recorded using a full-cell patch clamp. Expression of Kv4.2 in the substantia nigra was analyzed using a western blot assay. Serum malondialdehyde levels were analyzed by enzyme-linked immunosorbent assay. The motor coordination of mice was evaluated using the rotarod test. The results showed that fibroblast growth factor 20 decreased A-type potassium current in neurons of the substantia nigra, increased long-term potentiation amplitude in the hippocampus, and downregulated Kv4.2 expression. A high dose of fibroblast growth factor 20 reduced serum malondialdehyde levels and enhanced the motor coordination of mice. These findings confirm that fibroblast growth factor 20 has a therapeutic effect on the toxicity induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, and its mechanism of action is associated with the inhibition of A-type K+ currents and Kv4.2 expression. All animal procedures were approved by the Animal Care and Use Committee of Qilu Hospital of Shandong University, China in 2017(approval No. KYLL-2017-0012). 展开更多
关键词 nerve regeneration Parkinson’s disease 1-methyl-4-phenyl-1 2 3 6-tetrahydropyridine fibroblast growth factor 20 A-type potassium current long-term potentiation KV4.2 oxidative stress MALONDIALDEHYDE motor performance neural regeneration
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High Performance Liquid Chromatography Separation and Simultaneous Fluorometric Detection of Trace Amount of Polyamines in Cell Culture Media
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作者 王淳本 雷景迈 +1 位作者 柴锡禄 何善述 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 1995年第2期125-128,共4页
A highly sensitive and precise method for the determination of the polyamines (including putrescine, spermidine and spermine) in cell culture media is described. The samples were concentrated by C18 column and the pol... A highly sensitive and precise method for the determination of the polyamines (including putrescine, spermidine and spermine) in cell culture media is described. The samples were concentrated by C18 column and the polyamines were converted to fluorometric derivatives with DNS-Cl. The polyamine derivatives were then completely separated by HPLC and determined by simultaneous fluorometric detection. The CV of intragroup and intergroup were 2. 49 %-4. 26% and 4. 29 %-5. 16 %, respectively. The rate of recovery was 103%- 99%. There was trace amount of polyamines detected by this method in the media of F12, 8900, RPMI1640, DMEM and M199 even without incubation with cells. So this method can be used for detecting the changes of polyamines in a medium before and after incubation with cells. It is helpful for the researches on the regulation of cell proliferation by polyamines. 展开更多
关键词 medium PUTRESCINE SPERMIDINE SPERMINE high performance liquid chromatography fluorospectrophotometry
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A numerical case study on the long-term seismic assessment of reinforced concrete tunnels in corrosive environments 被引量:1
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作者 Maria Antoniou Antonios Mantakas +1 位作者 Nikolaos Nikitas Raul Fuentes 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第3期551-572,共22页
The paper investigates the long-term seismic behaviour of an underground reinforced concrete(RC)metro tunnel in Santiago,Chile,considering the combined effects of chloride-induced corrosion and cumulative,low-amplitud... The paper investigates the long-term seismic behaviour of an underground reinforced concrete(RC)metro tunnel in Santiago,Chile,considering the combined effects of chloride-induced corrosion and cumulative,low-amplitude seismic shaking on the structure’s performance.The soil-tunnel response is evaluated with the aid of transient,nonlinear finite element analysis using a two-dimensional(2D)plane strain numerical model that adopts advanced nonlinear models for the simulation of soil and concrete plasticity and the dynamic stiffness behaviour.The effects of corrosion deterioration are demonstrated in terms of time-dependent loss of rebar area and cover concrete stiffness and strength.The study illustrates the influence of ageing and repeated seismic shaking on lining deformation,crack development,and the modal characteristics of the intact and degrading systems.The results indicate that multiple lowamplitude events drive the non-degrading RC tunnel beyond its elastic regime without significant structural response consequences.A noticeable impact of corrosion deterioration on the structure’s seismic performance is revealed,increasing with the number and intensity of earthquake events.Two different tunnel embedment depths are comparatively assessed.The analyses demonstrate larger coseismic section convergence in the case of the deeper tunnel,yet a less pronounced effect of ageing and successive seismic loading compared to the shallow section,which is evident in the RC lining cracks at the end of shaking. 展开更多
关键词 TUNNELS Reinforcement corrosion Ageing EARTHQUAKES Numerical modelling long-term performance Concrete cracking behaviour
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Experimental Study on Electrorheological Performance of a Composite Material
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作者 陈淑梅 魏宸官 《Journal of Beijing Institute of Technology》 EI CAS 2003年第1期68-71,共4页
By using SrTiO 3/PANI as a dispersed phase and silicone oil as a dispersion medium, the rheological characteristic of the dispersion medium under an electric field and the ERF performances of the mixture of SrTiO 3/... By using SrTiO 3/PANI as a dispersed phase and silicone oil as a dispersion medium, the rheological characteristic of the dispersion medium under an electric field and the ERF performances of the mixture of SrTiO 3/PANI composite particles and silicone oil under different dispersed phase consistencies and different medium viscosities have been investigated. The measurements of the rheological characteristic, that is the shear stress of ERF, under shearing flow were performed with a Couette-type rheometer manufactured by HAAKE. It is proved that the rheological characteristic of the dispersion medium follows Newtonian fluid viscosity law and the ERF rheological characteristic of the mixture of the dispersion medium and dispersed phase obeys Bingham fluid model under electric field. The experimental result shows that the effects of different phase consistencies and different dispersion medium viscosities on ERF performances are great. The testing expressions of shear stress vs. electric field under different conditions have been obtained by polynomial fit, which is the theory foundation of application in engineering. 展开更多
关键词 SrTiO 3/PANI composite particles dispersion medium ERF performances
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Government Intervention and Support on SMEs Firm Performance
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作者 Elohor Katherine Idolor Olufemi Olabode Olayemi +1 位作者 Patrick Sunday Okonji Frank Alaba Ogedengbe 《Journal of Economic Science Research》 2022年第2期1-12,共12页
The small and medium enterprise firms are renowned for improving the na­tion’s economy through the provision of job opportunities for its populace,improving the financial and investment status of the countries a... The small and medium enterprise firms are renowned for improving the na­tion’s economy through the provision of job opportunities for its populace,improving the financial and investment status of the countries and provi­sion of innovative products that meets the need of the people.SMEs are key players in the economy,through sustainable development goals(SDGs)enabling them to thrive in the open business environment and actively applying the digital transformation,promoting inclusive and sustainable in­dustrialization should be the core of any country government.This research is designed to explore the influence of government intervention and support on enterprise performance and growth in five business sectors-Hospitality,Education,Health care,Bottled Water Production and Transport and Logis­tics organizations.The research paper had a descriptive research design with a randomly selected sample size of one hundred and ninety-seven respondents.The research hypotheses were tested using(Factor Analysis and Ordinal Logistic Regression Analysis)with Statistical Packages for Social Science(SPSS)version 25.The results of the study reveal that gov­ernment intervention policies and intervention programmes when instituted will promote the growth of business firms in Nigeria.Also identified are relevant recommendations that serve as motivation for policy administra­tors,entrepreneurs,and business managers to ensure that relevant interven­tion programme is adopted to boost performance and growth of the SME sector in Nigeria. 展开更多
关键词 Financial and resource allocation Managerial competence Government intervention and support Small and medium enterprise firm performance and growth
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考虑材料时变性的服役中小跨径桥梁横向地震响应分析
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作者 吴刚 郑钰 +3 位作者 邹友泉 吴必涛 王艺钦 黄云 《震灾防御技术》 CSCD 北大核心 2024年第3期536-547,共12页
构件材料性能会随服役时间的增加而退化,并导致桥梁结构抗震性能存在时变性。为探讨不同服役期下中小跨径桥梁抗震性能变化规律,以3跨预应力混凝土连续桥梁为例,通过分析材料力学性能指标时变性,量化不同服役期构件力学分析模型参数,并... 构件材料性能会随服役时间的增加而退化,并导致桥梁结构抗震性能存在时变性。为探讨不同服役期下中小跨径桥梁抗震性能变化规律,以3跨预应力混凝土连续桥梁为例,通过分析材料力学性能指标时变性,量化不同服役期构件力学分析模型参数,并考虑桥墩、挡块及支座等构件力学性能退化,采用OpenSees软件建立桥梁有限元分析模型。基于非线性时程分析结果,揭示服役中小跨径桥梁横桥向地震响应时变性。研究结果表明,随着服役时间的增加,材料力学性能发生退化,使中小跨径桥梁各构件抗震能力下降;相同水平地震作用下,中小跨径桥梁主梁及挡块位移响应随服役时间的增加而降低,而桥墩损伤程度加剧,构件震害程度与不考虑构件力学性能时变性时相差较大,其中板式橡胶支座刚度及摩擦系数时变性是关键。因此,在服役中小跨径桥梁抗震分析中,有必要同时考虑桥墩、挡块及支座力学性能退化。 展开更多
关键词 中小跨径桥梁 时变性 抗震分析 性能退化 非线性时程分析
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中深层水平连通地热井取热特性研究
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作者 张杰 王贵洋 +1 位作者 王鹏涛 王姝媛 《西南石油大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第5期161-169,共9页
高效取热技术是实现地热效益化开发的关键,建立了水平连通地热井数值仿真模型,计算了连续开采和间歇开采工况下的出口流体温度和换热量,研究了注入温度、注入流量、水平段长度对系统换热性能和岩层温度恢复能力的影响。结果表明,随着注... 高效取热技术是实现地热效益化开发的关键,建立了水平连通地热井数值仿真模型,计算了连续开采和间歇开采工况下的出口流体温度和换热量,研究了注入温度、注入流量、水平段长度对系统换热性能和岩层温度恢复能力的影响。结果表明,随着注入流量增加,地热井出口水温下降,但整个系统换热量提高;当注入温度较高时,可有效提高出口水温,但系统换热量降低较大;随着水平段长度增加,出口水温和换热量逐渐上升,换热性能提高;岩层温度恢复能力随注入流量和注入温度的增加而提高。综合考虑钻井成本、水泵功耗等因素,适量增加注入流量、降低注入温度、增加水平段长度能有效提高水平连通换热井的换热性能;虽然高的注入温度可提升岩层温度恢复能力,但不利于提高系统换热性能。 展开更多
关键词 中深层地热 水平连通地热井 换热性能 取热量 地温恢复能力
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我国民营银行的发展现状、问题与对策建议
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作者 宋士云 李树凤 《聊城大学学报(社会科学版)》 2024年第2期56-67,共12页
进入新时代以来,基于解决我国金融业发展不平衡不充分问题与优化金融市场结构体系的现实需要,国家出台了一系列政策支持民营银行的发展,民营银行由试点阶段进入到常态化经营阶段,资产负债规模和盈利能力大幅提升,逐渐成为服务中小企业... 进入新时代以来,基于解决我国金融业发展不平衡不充分问题与优化金融市场结构体系的现实需要,国家出台了一系列政策支持民营银行的发展,民营银行由试点阶段进入到常态化经营阶段,资产负债规模和盈利能力大幅提升,逐渐成为服务中小企业的主力军。然而,由于战略定位不清晰、公司治理机制待完善、资本金支撑不足、抗风险能力较弱等问题,目前民营银行正面临严峻的挑战。因此,在未来的发展中,民营银行应坚定差异化经营,注重小微、民营、普惠等领域;完善公司治理机制,拓展资本金来源渠道;加强人才队伍建设,提高金融服务质量;借助金融科技,加快数字化转型,提升风险识别、防控和化解能力。同时,政府部门要强化政策引导,完善监管措施,助力民营银行更好地服务于实体经济。 展开更多
关键词 民营银行 中小企业融资 经营绩效
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可持续视角下预算绩效管理的现实要求与实践方向
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作者 马蔡琛 管艳茹 《山东财经大学学报》 2024年第4期5-13,共9页
面对财政收支矛盾突出的现实,提升预算可持续性成为现代财政制度建设的重要内容。从可持续视角出发,预算总量的可控性、绩效约束的有效性、中期框架下的绩效保证,体现了新时代预算绩效管理的新要求。具体而言,通过提升预算透明度与强化... 面对财政收支矛盾突出的现实,提升预算可持续性成为现代财政制度建设的重要内容。从可持续视角出发,预算总量的可控性、绩效约束的有效性、中期框架下的绩效保证,体现了新时代预算绩效管理的新要求。具体而言,通过提升预算透明度与强化隐性债务绩效管理,加快推进阳光财政建设、有效化解预算风险;结合零基预算与绩效导向,合理确定预算优先序、加强预算绩效信息的有效应用;加强中期财政规划对年度预算的约束,并促进其与绩效管理的有效结合,进而实现预算绩效管理从年度向中期的可持续拓展。 展开更多
关键词 预算绩效管理 现代预算制度 财政可持续 中期财政规划
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中小微企业领导韧性赋能团队创新的心源动力机制———基于愿景沟通与团队行为意向
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作者 曾雪云 黄铮 叶滨 《北京邮电大学学报(社会科学版)》 2024年第2期12-26,共15页
基于社会信息处理理论,建立“韧性领导的社会信息处理过程-团队互动过程”分析框架,揭示韧性领导赋能团队创新的作用机制。对643个中小微企业的团队领导调查研究发现,领导韧性直接正向影响团队的综合创新绩效,并且相较于结果性创新(产... 基于社会信息处理理论,建立“韧性领导的社会信息处理过程-团队互动过程”分析框架,揭示韧性领导赋能团队创新的作用机制。对643个中小微企业的团队领导调查研究发现,领导韧性直接正向影响团队的综合创新绩效,并且相较于结果性创新(产品创新及市场创新),更可能影响潜在创新绩效(战略创新、行为创新、过程创新)。机制检验发现,团队行为意向在领导韧性和综合创新绩效之间发挥中介作用,愿景沟通则在领导韧性和团队行为意向之间具有中介作用。就组织环境而言,信任逆境和目标一致性逆境加强了领导韧性与愿景沟通的联系。上述结论揭示了领导韧性作用于团队创新的社会信息处理过程和情感激发过程,这一心源动力机制对促进中小微企业的创新发展具有重要意义。 展开更多
关键词 领导韧性 中小微企业 创新绩效 愿景沟通 团队行为意向
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