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Search Results: 1 - 10 of 32582 matches for " Zhiyao Huang "
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A New Method for Flow Rate Measurement in Millimeter-Scale Pipes
Haifeng Ji,Xuemin Gao,Baoliang Wang,Zhiyao Huang,Haiqing Li
Sensors , 2013, DOI: 10.3390/s130201563
Abstract: Combining the Capacitively Coupled Contactless Conductivity Detection (C 4D) technique and the principle of cross correlation flow measurement, a new method for flow rate measurement in millimeter-scale pipes was proposed. The research work included two parts. First, a new five-electrode C 4D sensor was developed. Second, with two conductivity signals obtained by the developed sensor, the flow rate measurement was implemented by using the principle of cross correlation flow measurement. The experimental results showed that the proposed flow rate measurement method was effective, the developed five-electrode C 4D sensor was successful, and the measurement accuracy was satisfactory. In five millimeter-scale pipes with different inner diameters of 0.5, 0.8, 1.8, 3.0 and 3.9 mm respectively, the maximum relative difference of the flow rate measurement between the reference flow rate and the measured flow rate was less than 5%.
Key Technologies for an Urban Overland Flow Simulation System to Support What-If Analysis  [PDF]
Guoqiang Peng, Fuqiang Lu, Zhiyao Song, Zhuo Zhang
Journal of Water Resource and Protection (JWARP) , 2018, DOI: 10.4236/jwarp.2018.107040
Abstract: Urban flooding poses serious threats to human life. In China, many cities have recently experienced flooding during every rainy season. Several years ago, policies, scientific methods, and engineering measures were applied to address this systematic problem. However, flooding disasters remain frequent in urban areas in China. Therefore, this article discusses the human-earth relationship from a philosophical perspective to analyse the causes of urban water problems. This article mainly illustrates the value of the what-if analysis concept and how to use this concept to address urban flooding issues and improve the management of urban overland flow. However, the existing simulation models and software do not effectively support what-if analyses. In particular, most existing urban hydrological simulation models and software do not sufficiently consider the heterogeneity of geographical objects on urban surfaces and lack interactions to support what-if analyses. These limitations hinder effective implementation of what-if analysis. This article introduces three key technologies that allow an urban overland flow simulation system to effectively support what-if analyses: 1) urban spatial automatic discretization and topo-adjacency, which reflect the heterogeneity of an urban area; 2) hydrological models for the simulation of the hydrologicalprocesses of the main geographical objects in the urban area; and 3) key strategies for a visual analytic platform to support what-if analyses in well-perceived way. The experiment was conducted using a community in Chongqing as a case study. The results demonstrate that the designed key technologies and functions of the proposed system can support what-if analysis and that what-if analysis is an important and useful concept for urban water management.
Effectiveness of Protected Areas in Maintaining Plant Production
Zhiyao Tang,Jingyun Fang,Jinyu Sun,Kevin J. Gaston
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0019116
Abstract: Given the central importance of protected area systems in local, regional and global conservation strategies, it is vital that there is a good understanding of their effectiveness in maintaining ecological functioning. Here, we provide, to our knowledge, the first such global analysis, focusing on plant production, a “supporting” ecosystem function necessary for multiple other ecosystem services. We use data on the normalized difference vegetation index (NDVI) as a measure of variation in plant production in the core, boundary and surroundings of more than 1000 large protected areas over a 25 year period. Forested protected areas were higher (or similar), and those non-forested were lower (or similar), in NDVI than their surrounding areas, and these differences have been sustained. The differences from surrounding areas have increased for evergreen broadleaf forests and barren grounds, decreased for grasslands, and remained similar for deciduous forests, woodlands, and shrublands, reflecting different pressures on those surroundings. These results are consistent with protected areas being effective both in the representation and maintenance of plant production. However, widespread overall increases in NDVI during the study period suggest that plant production within the core of non-forested protected areas has become higher than it was in the surroundings of those areas in 1982, highlighting that whilst the distinctiveness of protected areas from their surroundings has persisted the nature of that difference has changed.
The Changes in China's Forests: An Analysis Using the Forest Identity
Lei Shi,Shuqing Zhao,Zhiyao Tang,Jingyun Fang
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0020778
Abstract: Changes in forest carbon stocks are a determinant of the regional carbon budget. In the past several decades, China has experienced a pronounced increase in forest area and density. However, few comprehensive analyses have been conducted. In this study, we employed the Forest Identity concept to evaluate the changing status of China's forests over the past three decades, using national forest inventory data of five periods (1977–1981, 1984–1988, 1989–1993, 1994–1998, and 1999–2003). The results showed that forest area and growing stock density increased by 0.51% and 0.44% annually over the past three decades, while the conversion ratio of forest biomass to growing stock declined by 0.10% annually. These developments resulted in a net annual increase of 0.85% in forest carbon sequestration, which is equivalent to a net biomass carbon uptake of 43.8 Tg per year (1 Tg = 1012 g). This increase can be attributed to the national reforestation/afforestation programs, environmentally enhanced forest growth and economic development as indicated by the average gross domestic product.
An H2O flare in GGD25
Ye Xu,Xingwu Zheng,Dongrong Jiang,Fujun Zhang,Zhiyao Yu
Chinese Science Bulletin , 2001, DOI: 10.1007/BF03183204
Abstract: We report the observing results of a short time scale monitoring of the 22 GHz water maser emission in GGD25. A rapid water maser outburst with the time scales of 4 d has been detected, and the variations are accompanied by some changes in the line width. The time variations were probably caused by a collision pump which led to changes in the pump input.
Modelling the Molecular Transportation of Subcutaneously Injected Salubrinal
Andy Chen, Ping Zhang, Zhiyao Duan, Guofeng Wang and Hiroki Yokota
Biomedical Engineering and Computational Biology , 2012, DOI: 10.4137/BECB.S7050
Abstract: For the subcutaneous administration of a chemical agent (salubrinal), we constructed a mathematical model of molecule transportation and subsequently evaluated the kinetics of diffusion, convection, and molecular turnover. Salubrinal is a potential therapeutic agent that can reduce cellular damage and death. The understanding of its temporal profiles in local tissue as well as in a whole body is important to develop a proper strategy for its administration. Here, the diffusion and convection kinetics was formulated using partial and ordinary differential equations in one- and three-dimensional (semi-spherical) coordinates. Several key parameters including an injection velocity, a diffusion coefficient, thickness of subcutaneous tissue, and a permeability factor at the tissue-blood boundary were estimated from experimental data in rats. With reference to analytical solutions in a simplified model without convection, numerical solutions revealed that the diffusion coefficient and thickness of subcutaneous tissue determined the timing of the peak concentration in the plasma, and its magnitude was dictated by the permeability factor. Furthermore, the initial velocity, induced by needle injection, elevated an immediate transport of salubrinal at t < 1 h. The described analysis with a combination of partial and ordinary differential equations contributes to the prediction of local and systemic effects and the understanding of the transportation mechanism of salubrinal and other agents.
A Management Decision Support System for Forest Resources

Zhang Zhiyao,Chen Lijun,

系统工程理论与实践 , 1998,
Abstract: Based on the system of situation analysis and forecast assessment for forest resources, this paper puts forward the basic idea and construction suited to build management decision support system for forest resources. Meanwhile, it lists the system of basic parameter indexes and models of simulation control.
Parameter Identification of Diameter Distribution of Forest Trees

Zhang Zhiyao,Chen Lijun,

系统工程理论与实践 , 1998,
Abstract: This paper analyzes a discrete model based on continuous transferring equation of diameter distribution structure of forest trees, discusses parametric properties and the identification method. This method has significant value in prediction of the growing state of forest trees and optimal control of forest resources.

Chen Zhiyao,Li Shude,

大地测量与地球动力学 , 2008,
Abstract: It was the first time to take the maximum permissible error as the major specifications of the crustal deformation observation instrument in compiling the seismological industry standard.The specification is named the Technical requirements of instruments in network for earthquake monitoring-The instrument for crustal deformation observation.The maximum permissible error is the unique basis to judge the qualification of tilt instrument.According to the expression set from the Guide to the Expression of Uncertainty in Measurement,the judgment and the expression of the maximum permissible error of the tilt meter and strain meter have been determined.Finally,the expression of the uncertainty of measurement and the qualified judgment calculation are introduced.

Xie Kunqing,Li Zhiyao,

第四纪研究 , 2000,
Abstract: The primary objective of this paper is to probe an effective way of acquiring thetree-ring view singular value with a plate scanner and of applying the image analysisand digital process to dendrochronological research. Through the stahstical analysis oftree-ring image distribution charateristics and noise variation, a new algorithm ofimage segmentation and feature extraction is designed, and then a correspondingsoftware package of personal computer tree-ring image process system is developedaccording to the dendrochronological research character. As a result of the realprocess and the analysis combined with other methods of dendrochronological research,it is demonstrated that the approach of scanning image process is not only feasiblebut also more effective and accurate. Therefore, it will be possible to make thedendrochronological research and applicahon in environmenta change more widespreadand profound. The contents and achievements of the research are mainly reflected inthe following six aspects:(1) Establishing an effechve method by using the personal computer devices(including tLhe plate scanner) to acquire the tree-ring view singular value, whichimproves the measuring tree-ring way. Compared with other specialized devices, thismethod reduces the processing cost and makes the processing more efflciency andmore accuracy.(2) Making a systematic study and analysis in the tree-ring and its errordistribution with the image theory and the mathematics method, and proving theresearch way to be feasible through the theory and the practice.(3) Making full use of the two-dimension information of digital image to studythe variation in the tree-ring growth area and then to raise the reliability of statisticalanalysis.(4) Thviding a ring into earlywood and latewood areas by the image segmentprocess so that the time-scale analysis precision will be improved anddendrochronological research will be more profound.(5) Designing a quantitative index of the difference between earlywood mean grayvalue and latewood mean gray value as the indicator of tree-ring growth. The indexcan effectively restrain the influence of image noise on the statistic analysis oftree-ring gray value, and have a good response to climate changes, which can be used as a subshtute for maximum density of tree-ring in dendrochronological research.(6) Developing a software package to be applied to dendrochronological analysisand research based on the personal computer using Microsoft Visual C+ + language.
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