Papers by Keyword: Evolution

Abstract: Alumina (Al₂O₃) and Al₂O₃-based ceramics are candidate wear-resistant materials for many applications. In the past decades, the friction and wear behaviors of Al₂O₃ and Al₂O₃-based ceramics in dry sliding and lubricated conditions have been extensively investigated. In dry sliding, surface modification of Al₂O₃ and Al₂O₃-based ceramics at tribo-interface can be observed. In other words, the original surfaces of Al₂O₃ and Al₂O₃-based ceramics can be modified by friction and friction-induced material interaction (fracture, mechanical mixing, tribo-sintering) at the tribo-interface, and hence give birth to a tribo-layer. The formation and evolution of the tribo-layer on the worn surfaces of Al₂O₃ and Al₂O₃-based ceramics are the keys to understand the friction and wear behaviors of Al₂O₃ and Al₂O₃-based ceramics. This is conducted by scanning electron microscopy (SEM) observation and classification of the morphology and composition of the worn surfaces of Al₂O₃ and Al₂O₃-based ceramics at different sliding stages. The typical characteristics of the tribo-layers on the worn surfaces of Al₂O₃ and Al₂O₃-based ceramics in sliding against Si₃N₄ in a reciprocating motion are smooth surface with many interlinked cracks in morphology, mechanical mixing in chemical composition. The condition allowing the formation of the tribo-layer is briefly discussed.

Abstract: In most regions of China, rural housing is in a state of spontaneous evolution under no architects’ guidance, to explore the development regularity and spontaneous problems is the foundation heading to the good orientation. Take local rural dwellers in Jinzhou for example, with scientific methods of the field surveying and mapping, residents interview, questionnaire survey and so many kinds of scientific methods etc., the authors summarize the types of rural housing in Jinzhou and their evolution first and then the authors analyze the laws of the evolution and influencing factors to local dwellers. The paper aims to provide some theoretical bases for guiding the construction and reconstruction of rural housing, at present and in the future.

Abstract: The Qijiang historical town is a typical town of the settlement in central Sichuan, It's also the capital site of the ancient Qi country during the Spring and Autumn period. After thousands of years of evolution, it's still maintained a complete ancient space environment pattern now. The spatial form of historical town is simple and obvious, but the street space organization is in an orderly manner, yard surrounded close is flexible and ingenious, carrying an extremely rich intangible traditional culture and the historical heritage. Through to the summarizing and analyzing of the pace evolution characteristics of Qijiang historical towns, we can explore the historical landscape characteristics of the town and help to further study of the dependency relationship between material culture and intangible cultural in space environment. Especially to studying the formation and development of space of historical town and Qi Kingdom country. It's also can provide reference in protection and restoration of the historic, ecological and sustainable spatial forms of historical town .

Abstract: With the rapid development of science and technology of concrete, the direction of research is changing from single high strength to high performance (strength and durability).Admixtures can improve concrete workability and improve resistance corrosion, especially it can inhibit alkali-aggregate reaction. Admixtures are paid attention to researchers in this field. In order to realize research and application of high performance concrete for the better, this paper systematically expounds the mineral admixtures and biomass admixtures. Mineral admixtures cost is higher, and it is limited available resources. Biomass admixtures have recycling, sustainable application and other characteristics, so it has the very good application prospects.

Abstract: Systems biology is a term used to describe a number of trends in bioscience research, and a movement which draws on those trends. Systems biology aims to understand the biology from the system level. The fundamental challenge of systems biology is to establish a complete, detailed description of the link between biological molecules and to study molecular interactions and the close association between the physiological responses. Systems biology methods in the system under the guidance will enable us to break the shackles of the old research model to study life from the grasp of the whole phenomenon. We must effectively grasp and follow the systems biology approach to guide our biological research practice.

Abstract: This article builds up nodes growth model based on weighted network and analyzes the evolution characteristics of railway hub logistics spatial network (LSN) under passenger dedicated line conditions. The results show that impelled by passenger dedicated line, the logistics amount of railway hub tends towards agglomeration and distributes more irregularly among stations; The network possesses convergence yet is unlikely forming a single center network because of the effect of the attractiveness of nodes and the weights of edges of railway hub LSN, but will split up into multi-center hierarchy network. It is also demonstrated by statistical data of logistics nodes of Guangzhou railway hub in one year pre-and-post-operation of Wuhan-Guangzhou passenger dedicated line.

Abstract: The capillary porous structures of the pre-cast concrete with different initial steam-curing duration were analyzed with MIP techniques. Then the hydration degree of cement, fly ash and slag in pre-cast concrete versus time were obtained respectively by combing the hydrochlorides and EDTA selecting dissolution methods, based on which the corresponding evolution of capillary porosity was determined. The comparison between calculated results and experimental capillary porosity showed that the proposed evolution model of capillary porosity could be adopted to reveal the developing trend of capillary porosity of pre-cast concrete with fly ash and slag under certain curing conditions

Abstract: This paper extracted green space distribution information from multi-temporal LANDSAT multi-spectral remote sensing images to analyze the evolution of Nanjing’s green space between 1988 and 2007. The findings suggest that the current distribution of green space is not balanced and that the total area of green space has decreased over time. The trend towards fragmentation is obvious in the disproportionately large decline in medium-sized green spaces. Mountain forest and other large green spaces, however, have been better protected. Before 1998, the fragmentation was most apparent in the green spaces of the city’s inner circle. After 1998, the green space in the city’s middle circle began to suffer from the effects of severe human interference. After 2003, the outer circle of green space began to fragment and diminish as a result of urbanization, and the original ecological corridor surrounding the city collapsed.

Abstract: With the progress of human, the society is progressing. All products involved in society also are constantly evolving. Actually, technological system has its own technological evolution like the biological evolution. Technology evolution is not accidental, but driven by some factors. And every kind of driving force is happened according to certain principles. This paper proposed nine driving force of products technological evolution as well as the evolution theory. At last, a case study of the mobile phone verified the proposed theory.

Abstract: Evolution characteristics of primary phase in A356 alloy at the different isothermal holding temperatures and time were investigated. The results showed that there were the effects of the isothermal holding temperature and time on the evolution of primary phase, and microstructure changed from dendritic-like to rosette-like, and then to particle- or globular-like with the decrease of holding temperature. The suitable technology in the test was obtained, in which when being held at 600°C for 5min, the roundness and size of primary became better.