Dynamic behavior of new cutting subgrade structure of expensive soil under train loads coupling with service environment

Expansive soil is sensitive to dry and wet environment change. And the volume deformation and inflation pressure of expansive soil may induce to cause the deformation failure of roadbed or many other adverse effects. Aimed at a high-speed railway engineering practice in the newly built Yun-Gui high-speed railway expansive soil section in China, indoor vibration test on a full-scaled new cutting subgrade model is carried out. Based on the established track-subgrade-foundation of expansive soil system dynamic model test platform, dynamic behavior of new cutting subgrade structure under train loads coupling with extreme service environment(dry, raining, and groundwater level rising) is analyzed comparatively. The results show that the subgrade dynamic response is significantly influenced by service conditions and the dynamic response of subgrade gradually becomes stable with the increasing vibration times under various service environment conditions. The vertical dynamic soil stress is related with the depth in an approximate exponential function, and the curves of vertical dynamic soil stress present a "Z" shape distribution along transverse distance. The peak value of dynamic soil stress appears below the rail, and it increases more obviously near the roadbed surface. However, the peak value of dynamic soil stress is little affected outside 5.0 m of center line. The vibration velocity and acceleration are in a quadratic curve with an increase in depth, and the raining and groundwater level rising increase both the vibration velocity and the acceleration. The vertical deformations at different depths are differently affected by service environment in roadbed. The deformation of roadbed increases sharply when the water gets in the foundation of expansive soil, and more than 60% of the total deformation of roadbed occurs in expansive soil foundation. The laid waterproofing and drainage structure layer, which weakens the dynamic stress and improves the track regularity, presents a positive effect on the control deformation of roadbed surface. An improved empirical formula is then proposed to predict the dynamic stress of ballasted tracks subgrade of expansive soil.

Low-dimensional perovskite modified 3D structures for higher-performance solar cells

For solution prepared perovskite solar cells,metal halide perovskite materials with low-dimensional(LD)are flexibly employed in 3D perovskite solar cells to promote efficiency and long-term stability.In this review,the various structures,properties,and applications of LD perovskites are firstly summarized and discussed.To take advantage of LD materials,LD perovskites are introduced in the 3D bulk and/or the interface between the perovskite thin film and the carrier transporting layer to passivate the gain boundary defects while providing the stability advantage of LD materials.Therefore,the preparation methods and crystallization control of the LD perovskite layers are discussed in depth.Then,the combined devices using both LD and 3D components are reviewed on the basis of device design,cell structure,interface charge transfer,energy lever alignment,and synergistic improvement of both efficiency and stability.Finally,the challenges and expectations are speculated for further development of perovskite solar cells.

Reliability-based service life prediction of existing concrete structures under marine environment

Chloride-induced corrosion of the reinforcement is considered as one of the major mechanisms resulting in the reduction of structural resistance of reinforced concrete structural elements located in marine and other aggressive environments. A study of reinforced concrete structures located at the Fangcheng dock in the Beibu Gulf port, China, was present. The result from field survey indicates that the concrete cover depth and chloride diffusion coefficient fit best normal distribution and lognormal distribution, respectively. The service life of structure is about 55 a, while initiation time is 45 a. Sensitivity analysis indicates that the most influential factor of the structure service life prediction is concrete cover, followed by diffusion coefficient, diffusion decay index, critical chloride concentration, surface chloride concentration, current density and localized pitting corrosion. Finally, the effects of diffusion decay index and critical chloride concentration on structure service life prediction are discussed.

Validating the Classification of Smallholder Dairy Farming Systems Based on Herd Genetic Structure and Access to Breeding Services

Smallholder dairy farming in Africa is classified into rural, peri-urban and urban systems. The major classification criterion is demographic. Dairy systems are extensively characterized, but not based on rigorous statistical analyses. We validated this classification based on herd genetic structure and identify determinants of within-system variations, taking Ethiopia as a case study. Discriminant function analysis correctly classified 38% - 50.6% of the 360 sampled farms into the three systems. Multinomial logistic regression analysis showed that rural and peri-urban farmers were 1.26 (P < 0.1) to 1.45 (P < 0.001) times more likely to keep local and low grade crossbreds and fewer high grade crosses (P < 0.05;odds ratio = 2.35) than the urban farmers. In the rural system, proportion of high grade crosses declined and low grades increased over generations, whereas in urban system the reverse was observed. Access to breeding services and land resources significantly determined the adoption of crossbred dairy herd within systems. In conclusion, considering farms within systems as a uniform unit to target development interventions may not be appropriate and thus farm topologies and system specific determinants of farmers’ breeding strategies need to be considered to design and introduce appropriate breeding interventions.

Study on Construction of Forestry Socialized Service Systems Based on Barnard's Organizational Structure Theory

Construction of forestry socialized service systems is the important content for reform of collective forestry tenure systems.Based on the necessity,possibility and problem of construction of forestry socialized service system,according to Barnard's Organizational Structure theory,the path and countermeasure of forestry socialized service system in China are discussed.

An Empirical Research of Producer Services＇ Cluster Development To Regional Industrial Structure Optimization And Upgrading --Based on the Research of 16 central cities＇ Panel Data in Yangtze River Delta

Based on the 16 central cities＇ Panel Data in Yangtze River Delta, location quotient index is used in this paper to measure and analyze the current cluster situation of producer services in Yangtze River Delta, fixed effects model of Panel Data model is also used in this paper, and the industrial structure is taken as the dependent variable, while the core explanatory variables is the degree of producer services＇ cluster development, which is calculated by location quotient, moreover, three control variables introduced in this paper and they are technology advantage, education level and R＆D spending, and the mentioned above is to empirically study the impacts of producer services＇ cluster development to the regional industrial structure. As a result, producer services＇ cluster development has a significant positive role in promoting the regional industrial structure optimization and upgrading, though the extent is not yet a big push and is still to be further strengthened. In this paper, it has provided a strong evidence that under China＇ s new normal economy, producer services is badly needed to promote regional industrial structure, and finally it makes specific suggestions based on the current cluster situation of producer services in Yangtze River Delta.

Optimization of Land Use Structure Based on Ecological GREEN Equivalent

Optimization of land use structure consists of economic and social and ecological optimization.Applying the minds of system engineering and principles of ecology,this paper presents such thoughts:the optimal forest_coverage rate calculated according to the reality of a district is set as main standard of ecological rationality in the district;through considering the value of ecosystem services of the land with GREEN equivalent (mainly cultivated land and grassland)and based on the rule,GREEN equivalent,this paper introduces the area conversion between woodland and cultivated land,also between woodland and grassland;this paper establishes a multi_dimension controlling model of optimization of land use structure.In addition,a multi_objective linear programming model for optimization of land use structure is designed.In the end,this paper tests and verifies this theory of ecological optimization,taking Qionghai city in Hainan Province as an example.

Strengthening Steel Joint of Architectural Structure under Loading Condition

Through the comparative analysis of steel plate reinforced, ceramics reinforced and non- reinforced joints under loading condition, the feasibility of strengthening steel joint of architectural structure was studied. By using element birth and death technology simulation of the finite element software ANSYS, it is found that when the reinforced structure is 10 mm in thickness and using steel structure to reinforce the concemed areas, the equivalent stress in concerned regionals reduces by 31.1% compared with that when the structure is not reinforced. When reinforced with ceramics, the equivalent stress in concerned regionals reduces by 24.1% compared with that reinforced with steels; when the reinforced structure is 20 mm in thickness using steels to reinforce the concerned area, the equivalent stress in concerned regionals reduces by 39.4% compared with that when the structure is not reinforced. When using ceramics to reinforce the concerned areas, the eauivalent stress only decreases by 3.7% compared with that reinforced with steels.

Problems of durability and reinforcement measures for underground structures in China

In this paper, the bolt- and cable-supported structures mainly refer to anchored cables, anchored bolts, soil nails and other commonly used reinforcing and supporting structures in geotechnical engineering, as well as reinforced soil structures in permanent works. They are often used in combination, or formed into composite bolt-and cable-supported structures, with other traditional construction methods and relevant measures. Distinct characteristics of such structures are that they are most often invisible, exposed to more severe underground corrosive environments and with strict durability requirements. A number of serious durability problems of underground structures are discussed and major achievements and advances in China and abroad in terms of durability and reinforcement measures for underground structures are reviewed, followed by comprehensive analyses. Some suggestions for those problems are put forward.

An Analysis of Public Service Structural Imbalances in Rural China

Rectifying the structural imbalance between the provision of and demand for rural public services can effectively boost the efficiency of public funds utilization and the level of public service provision. Based on the findings of a field survey, this article presents a summary of the structural imbalance between the provision of and demand for rural public services. This paper holds that the structural imbalance is primarily reflected in the dislocation between provision and demand, the unsuitable mode of provision, the monolithic provision mechanism, the excessive focus on construction at the expense of governance and the overemphasis of counties and townships at the cost of villages. Such structural imbalance is principally because of the limited financial strength of government at the grass-roots level due to treasury centralization and the over-dependence of public services on special funds allocated by government at or above provincial level.

Application of Structural Equation Modeling to Evaluate Service Quality of Sportswear Retailing

Structural Equation Modeling （SEM） used widely in sociology, economics and psychology is adopted. Based on data obtained from marketing research, and using statistical analysis software SPSSll. 0 and LISRELS. 7, Theory of Five Dimensions of service quality is proved to be suitable in sportswear retailing in China. It analyzes the relationship among five dimensions and puts them in order of importance as to service quality in sportswear retailing. Advices are given for sportswear retail companies to improve their .Service quality and enhance customer loyalty.

Structural Dimensions Analysis of Service Employees' Innovation Behavior Based on Structural Equation Model

In order to know about the essence of service employees' innovation behavior, the service employees' innovation behavior scale based on their unique characteristics is designed. Data were collected from high-star hospitalities. Through the issuance and the collection of questionnaires, the scale is verified to have good reliability and validity by SPSS software analysis. Meanwhile,the structural equation model( SEM) is suited for testing structural dimensions of service employees' innovation behavior. The results showed that service employees' innovation behavior could be decomposed into a four-dimensional structure,namely innovation orientation, ideas generation, innovation implementation and innovation practice. In addition,there are significant differences in service employees' innovation behavior about subjects' gender,position,education background and years of working.

Research on the Socialization of Grassroots Meteorological Services in Agricultural Supply-side Structural Reform

In 2017, the No. 1 Document of the Central Committee proposed that "it is necessary to further promote agricultural supply-side structural reform, accelerate the cultivation of new kinetic energy for agricultural and rural development, and create a new situation in the construction of agricultural modernization". Under the new normal, Zhejiang s agricultural development shows new characteristics and new trends of speed change, structural optimization, and power conversion, and meteorological services for agriculture have stronger demands, higher requirements, and heavier tasks. The socialization of meteorological services is a new type of system arrangement for the provision of meteorological services, and aims to provide high-quality and efficient meteorological service products for the public and promote the equalization of basic meteorological services in urban and rural areas. In this study, through research on the socialization of grassroots meteorological services in a new situation, a new way of the government to provide public weather services is proposed, and a mechanism of the government to purchase public meteorological services is established;social resources and forces are organized and guided to develop the innovation system and mechanism of public weather services, and social resources are fully mobilized to meet the demand for meteorological services in the process of agricultural supply-side structural reform.

Exploring tree diversity and stand structure of savanna woodlands in southeastern Sudan

Savanna woodlands in Sudan host great biodiversity, provide a plethora of ecosystem goods and services to local communities, and sustain numerous ecological functions. Although the importance of the Acacia trees in these areas is well known, up-to-date information about these woodlands' diversity is limited and changes in their woody vegetation composition, density, diversity and relative frequency are not monitored over time. This study explored tree diversity and stand stage structure in Nuara Reserved Forest, a typical savanna woodland ecosystem in southeastern Sudan. A total of 638 circular sample plots(1000 m^2 for each) were established using a systematic sampling grid method. The distance between plots was 200 m. In each plot, all living trees with diameter at breast height(DBH) ≥5.00 cm were identified and counted, and their DBH values were recorded. From these data, tree composition, diversity, density and stage structure were assessed. There were 12,259 individual trees representing four species(Acacia seyal, Balanites aegyptiaca, Acacia Senegal and Acacia mellifera) that belong to two families. The dominant species was Acacia seyal. Average tree density was 191 trees/hm^2 and the Shannon-Weiner index for trees diversity was 0.204. Overall, young trees comprised 86.30% of the forest. The state of tree richness and density in the study area was low compared to other similar environments in the region and around the world. We recommended adoption of a proper management system that includes monitoring of woody vegetation diversity in this forest, and management actions to enhance tree diversity and sustain ecosystem services to local communities. In addition to care for the dominant Acacia seyal stands, more attention and conservation should be devoted to reestablishing Acacia senegal and Acacia mellifera trees because of their high ecological and economic values for local communities.

Optimal Hybrid Precoding Based QoE for Partially Structured Massive MIMO System

Precoding is a beamforming technique that supports multi-streamtransmission in which the RF chain plays a significant role as a digital precoding at the receiver for wireless communication. The traditional precodingcontains only digital signal processing and each antenna connects to each RFchain, which provides high transmission efficiency but high cost and hardwarecomplexity. Hybrid precoding is one of the most popular massive multipleinput multiple output (MIMO) techniques that can save costs and avoid usingcomplex hardware. At present, network services are currently in focus with awide range of traffic volumes. In terms of the Quality of Service (QoS), it iscritical that service providers pay a lot of attention to this parameter and itsrelationship to Quality of Experience (QoE) which is the measurement of theoverall level of user satisfaction. Therefore, this paper proposes hybrid precoding of a partially structured system to improve transmission efficiency andallocate resources to provide network services to users for increasing the usersatisfaction under power constraints that optimize the quality of basebandprecoding and radio frequency (RF) precoding by minimizing alternatingalgorithms. We focus on the web browsing, video, and Voice over IP (VOIP)services. Also, a Mean Opinion Score (MOS) is employed to measure thelevel of user satisfaction. The results show that the partially structured systemprovides a good user satisfaction with the network’s services. The partiallystructured system provides high energy efficiency up to 85%. Considering webservice, the partially structured system for 10 users provides MOS at 3.21 whichis higher than 1.75 of fully structured system.

Application of Structural Equation Model to Evaluate the Perception of Service Quality of Medical Staffs of infectious Disease Department in Chinese Hospitals

Objective To enhance the quality of medical service for Chinese patients through research of service quality from Chinese medical personnel. Methods Serv Qual scale was used for infection medical staffs randomly by sampling questionnaire in Beijing, Shanghai, Chengdu, Chongqing, Guangzhou and Nanning. The data collected were entered and analyzed using SPSS 20.0. Statistical methods included frequency, factor analysis, reliability analysis, correlation analysis, independent samples t test, one-way analyses of variance, simultaneous regression analysis and structural equation model analysis. Results The Kaiser-Meyer-Olkin value for the factor analysis of the scale was 0.970. The Cronbach's α for the reliability analysis was 0.975. The Pearson correlation coefficients were 0.624-0.874 and statistically significant. Undergraduates felt good, Ph D students felt bad; the doctors felt bad; managers felt good. Standard 5 dimensions of the regression coefficients were positive, including empathy(β = 0.288), reliability(β = 0.241) impacting on perceived service quality mostly. The control ability and stability of the standard error of perceived service quality directly effected value were 0.646 and 0.382, respectively. Conclusions Medical staffs of infectious disease department have poor perception of service quality. Hospitals should improve awareness and of clinicians and deepen the reform of the medical care system.

Dynamic Crowd Loading Test on Tibetan Ancient Structures

The field test of a typical Tibetan ancient structure instrumented with displacement and acceleration transducers was conducted to measure time histories due to crowd walking and running. The test case is introduced firstly. The displacement time histories are then used to analyze the dynamic property such as fundamental frequency of vertical vibration and damping ratio of the test structure, and the acceleration time histories are applied to evaluate the floor vibration serviceability. The floor interaction and comparison of human walking and running are also discussed. Some valuable conclusions are given.

Evaluation of restoration success in arid rangelands of Iran based on the variation of ecosystem services

The plantation of non-native species is one of the most expensive ecological restoration measures in arid and semi-arid areas,while its impacts on local communities are largely ignored.This study assessed the rate of change and the dynamic degree of the economic values of ecosystem services related to local conservation(water yield,stocking rate and aesthetic value)and preserving the future(carbon sequestration,soil protection,soil stability and habitat provision)to determine the restoration success of the plantation of non-native species Haloxylon ammodendron(C.A.Mey.)Bunge ex Fenzl(15-and 30-year-old)in parts of arid rangelands of Bardsir region,Kerman Province,Iran.We investigated the impacts of the two plantations on the seven ecosystem services and ecosystem structures(horizontal and vertical structures,vegetation composition and species diversity)based on field sampling and measurements at four sampling sites(i.e.,control,degraded,and 15-and 30-year-old plantation sites)in spring and summer of 2022.The restoration success of the plantation of non-native species was then examined by assessing the rate of change and the dynamic degree of the total economic value of all ecosystem services as well as the rate of change and the dynamic degree of the economic values of ecosystem services for the two groups(local conservation and preserving the future).Although the plantation of non-native species H.ammodendron enormously improved the vertical and horizontal structures of ecosystems,it failed to increase species diversity and richness fully.Further,despite the plantation of non-native species H.ammodendron had significantly increased the economic values of all ecosystem services,it was only quite successful in restoring carbon sequestration.Path analysis showed that plantation age had a significant impact on restoration success directly and indirectly(through changing ecosystem structures and services).The dynamic degree of the economic values of ecosystem services related to local conservation and preserving the future at the 15-and 30-year-old plantation sites indicated that the two plantations successfully restored the ecosystem services related to preserving the future.The presented method can help managers select the best restoration practices and predict their ecological-social success,especially for the plantation of high-risk non-native species in arid and semi-arid areas.

A full-section asphalt concrete waterproof sealing structure for the high-speed railway subgrade

Purpose–This study aims to investigate the service performances of a new full-section asphalt concrete waterproof sealing structure(FSACWSS)for the high-speed railway subgrade through on-site tracking,monitoring and post-construction investigation.Design/methodology/approach–Based on the working state of the waterproof sealing structure,the main functional characteristics were analyzed,and a kind of roller-compacted high elastic modulus asphalt concrete(HEMAC)was designed and evaluated by several groups of laboratory tests.It is applied to an engineering test section,and the long-term performance monitoring and subgrade dynamic performance testing system were installed to track and monitor working performances of the test section and the adjacent contrast section with fiber-reinforced concrete.Findings–Results show that both the dynamic performance of the track structure and the subgrade in the test section meet the requirements of the specification limits.The water content in the subgrade of the test section is maintained at 8–18%,which is less affected by the weather.However,the water content in the subgrade bed of the contrast section is 10–35%,which fluctuates significantly with the weather.The heat absorption effect of asphalt concrete in the test section makes the temperature of the subgrade at the shoulder larger than that in the contrastive section.The monitoring value of the subgrade vertical deformation in the test section is slightly larger than that in the contrastive section,but all of them meet the limit requirements.The asphalt concrete in the test section is in good contact with the base,and there are no diseases such as looseness or spalling.Only a number of cracks are found at the joints of the base plates.However,there are more longitudinal and lateral cracks in the contrastive section,which seriously affects the waterproof and sealing effects.Besides,the asphalt concrete is easier to repair,featuring good maintainability.Originality/value–This research can provide a basis for popularization and application of the asphalt concrete waterproof sealing structure in high-speed railways.

数字经济能够促进中国服务业发展吗?

基于2011-2020年省级面板数据,通过构建固定效应模型,验证数字经济对服务业、生产性服务业和生活性服务业发展的影响并提出相关对策建议。研究表明:一、数字经济对服务业和生产性服务业的发展具有显著的促进作用,但对生活性服务业的促进作用不显著。二、数字经济对东部地区的生产性服务业有显著促进作用,但在中西部地区这种作用不明显;2015年前,数字经济对服务业和生产性服务业的促进作用明显高于2015年后的促进作用。三、数字经济的发展有助于推动服务业结构的优化,提高整体服务业发展质量;数字经济的发展依赖于技术创新和产业集聚。在研究结论的基础上,本文从加快服务业的数字化转型,促进不同地区间的数字红利共享;加大对中西部地区服务业转型的扶持力度,弥合区域间的“数字鸿沟”;促进数字资源在现代服务业的产业链中的互联互通等提出对策建议。