Papers by Keyword: Distribution

Abstract: In wireless sensor networks, clustering class routing protocol is an important protocol type. Different clustering methods, and cluster head selection method directly affects the energy consumption of the entire network communication. This paper studies the effect of different partition methods of the network energy consumption, and to study the partitioning methods under the conditions of uneven distribution of nodes. We believe that energy efficiency clustering method should adapt the distributed of sensor nodes in order to improve energy efficiency. And according to the partition method we propose a low-power adaptive clustering routing protocol based on node distribution to partition. The protocol can effectively extend the lifetime of a wireless sensor network. Simulation results show that the proposed protocol can effectively prolong the network lifetime.

Abstract: The SiC ceramic membrane supports by using four different processes were prepared by extrusion molding process. Shape and distribution of pores in SiC ceramic membrane supports were observed by SEM, Meanwhile the O-ring strength was measured. By analyzing the relationship between pores’ shape, distribution and O-rings strength, the optimal data of apparent porosity and the optimal pores’ shape and distribution was obtained. By means ofusing similar particle sizes, particles modification, controlling drying rate of the green body and controlling the contents of glass phase in neck part between SiC particles formed at the high temperature, the SiC ceramic membrane supports with the O-ring strength greater than 20 MPa were prepared.

Abstract: This article summarizes the main topics related to the issue of particle size analysis. It provides a discussion of the term ’particle’ and briefly describes the advantages and disadvantages of the most important particle size analysis methods.

Abstract: Charge trapping behavior in Al₂O₃/SiC MOS structures was investigated by C-V hysteresis measurements in combination with XPS analysis. According to the quadratic fit of C-V hysteresis vs. t_ox curves, the density of the injected charges in the bulk Al₂O₃ films are the same under different maximum electric field, while the density of sheet charges increase with the increase of maximum electric field. Thus, a simple sheet charge model has been used to evaluate the actual effect of the electron injection phenomenon. The charge trapping levels can be as high as 10¹³ cm^-2, indicating the importance of C-V hysteresis in Al₂O₃/SiC structures. All the trapping charges are found to be located at a distance ranging from 3 to 4 nm from the interface. Furthermore, no detectable interface oxide between Al₂O₃ and SiC has been found through our XPS measurements. We conclude that the origin of charge trapping sites in Al₂O₃/SiC structures is the native defects in ALD Al₂O₃ layer and predominantly the border traps in the Al₂O₃ near the oxide/semiconductor interface.

Abstract: With the rapid urbanization and economic growth in China especially near 2 decades, the vast amount of municipal solid waste (MSW) were produced annually. Landfills are the predominant disposal sites for MSW in China, receiving more than 75% of the collected MSW every year. While the volume concentration is usually less than 1%, NMOCs are generally considered as the main source of the odorous problem at MSW landfills, because they include many compounds with very low odor thresholds. What’s more, aromatics is vital part of NMOCs for its toxic effect, which contains Benzene. The main objective of this study was to understand the comprehensive behavior of aromatics of landfill gas. In this work we present an integrated evaluation of working surface concentration distribution and emission rate of a municipal solid waste landfill. And in order to understand the transportation of aromatic, a new parameter was introduced to analyze this process. Thus, result shows, the fugitive emission of aromatics in the operating surface may need pay more attention. The highest average concentration for aromatics was found in autumn. Aromatic’s emission rate in winter was larger than autumn, the highest emission rate of aromatics toluene, 0.011g/m²/h. The B:T ratio in winter was significant higher that of other seasons.

Abstract: The logistics distribution modes have always been the bottleneck factors that restrict the development of fresh agricultural products’ e-commerce. Based on the studying of traditional logistics distribution modes, this paper points out five problems of how to create the e-commerce logistics distribution system. This thesis analyses the e-commerce logistics distribution modes of fresh agricultural products and the business process; summarizes the advantages and problems of the e-commerce logistics distribution of fresh agricultural products; finally, puts forward reasonable suggestions for fresh agricultural products e-commerce logistics distribution mode.

Abstract: Research on the existing industrial architectural heritages in Songyuan,sums up its characteristics in Sonyuan city distribution, describes the basic features of Songyuan City industrial architectural heritage in terms of building types, features, impact, etc, and provide basis for the study of strategies for conservation and utilization of industrial heritage in Songyuan City.

Abstract: Nebkha plays a major role in the ecological and environmental stabilization by accumulating wind-blown sediments around shrubs. Grain-size characteristics of different positions on nebkha reflect the sorting effect of aeolian dynamics. Based on the collected sand grains of different positions on four types of nebkhas at the southern fringe of Taklimakan Desert, China, this paper provided detailed insight into variability of the grain size of surface sand on nebkhas. The results showed that: a) Grain-size distributions on shield-shaped Karelinia caspica Nebkhas under natural condition had the larger spatial variability in comparison with the others. b) Grain size on nebkhas regularly showed the spatial variation. Grain size was increasingly larger along the windward slope upward, and then became finer along the leeward slope downward. c) The grain-size sortings of different positions on shield-shaped Alhagi sparsifolia Nebkhas under new reclaimed land were the best.

Abstract: This paper analyzed the seasonal and vertical variations of cyanide in Jiaozhou Bay, and tried to reveal the transfer processes based on investigation data in different seasons in 1982. Results showed that cyanide contents in surface waters were showing obvious seasonal variations, and were in orders of spring < summer < autumn, due to the inputs of cyanide were mainly occurred in wet season. The vertical variations seem to be not regular, and the influences of cyanide contents in surface waters to bottom waters were not significant, because the degradation of cyanide were rapid in summer and early autumn, leading to most of the cyanide was degraded before or in the process of sedimentation.

Abstract: This paper analyzed the content, distribution and source of Cu in Jiaozhou Bay in 1982. Results showed that the Cu contents in surface waters were relatively low, and the pollution level of Cu in 1982 was very slight. The major Cu source in the southwest of the bay was overland runoff; while for the northeast ocean current was responsible. The input contents of overland runoff and ocean current ranged from 2.22-3.56 μg.L^-1 and 0.15-5.31μg.L^-1, respectively.