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Search Results: 1 - 10 of 14082 matches for " Jichao Jia "
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Characteristics and Spatial Variability of Saline-Alkaline Soil Degradation in the Typical Yellow River Delta Area of Kenli County, China  [PDF]
Zhuoran Wang, Gengxing Zhao, Mingxiu Gao, Chunyan Chang, Jichao Jia, Jin Li
Journal of Environmental Protection (JEP) , 2014, DOI: 10.4236/jep.2014.512104
Abstract: As an important area of reserve land resources, the Yellow River Delta is faced with the problem of soil salinization. Grasping the characteristics of soil salinity as well as its spatial variation patterns is an important foundation of prevention, control and utilization of saline soil. This study selected Kenli County of the Yellow River Delta, obtained soil salinity data through field survey and lab experiment, and used statistical, GIS interpolation and buffer analysis methods to analyze the characteristics of soil salinity and its spatial variation patterns. Our results showed that the general soil salinity in the study area was mainly moderate and there was a significant positive correlation between different soil layers of 0 - 15 cm, 15 - 30 cm and 30 - 45 cm and soil salinity increased with the increase of soil depth. The areas with high soil salinity in each soil layer mainly distributed in the east near the Bo Sea in the county, while the areas with lower soil salinity mainly distributed in the southwest, centre and the two sides of the Yellow River in the northeast. Soil salinity showed a trend of decrease with the increase in distance to the Bo Sea, while stretching from the Yellow River, it showed increase tendency with the increase in distance to the Yellow River. The order from high soil salinity to low of different vegetation types was naked land → suaeda glauca → tamarix → vervain → reed → couch grass → paddy → cotton → winter wheat → maize; the order for different geomorphic types was depression → slightly sloping ground → slow hillock → high flood land. This study preliminary delineated the characteristics of soil salinity as well as its spatial variation patterns in the study area, and provided scientific basis for soil resource sustainable utilization in the Yellow River Delta.
Information Extraction Method of Soil Salinity in Typical Areas of the Yellow River Delta Based on Landsat Imagery  [PDF]
Tongrui Zhang, Gengxing Zhao, Chunyan Chang, Zhuoran Wang, Ping Li, Deyu An, Jichao Jia
Agricultural Sciences (AS) , 2015, DOI: 10.4236/as.2015.61006
Abstract: In order to get RS method to extract soil salinity of the Yellow River Delta, we set Kenli County as typical Yellow River Delta to be research area and get data of soil salinity through field investigation. By using RS image of Landsat-8 of March 14, 2014 and analyzing information features of each band and surface spectral features of research areas, we select out sensitive bands and build Soil Salinity Information Extraction (SSIE) model and vegetation index NDVI model for comparison. And then, we accordingly classify grades of soil salinity and get soil salinity information by decision tree approach based on expert knowledge. The results show that overall accuracy of SSIE model is 93.04% and coefficient of Kappa is 0.7869, while overall accuracy of NDVI model is 83.67% and coefficient of Kappa is 0.7017 respectively. By comparing with measured proportions of each class, we see that results from SSIE model is more accurate, which indicates significant advantage for soil salinity information extraction. This research provides scientific basis to get and monitoring soil salinity of the Yellow River Delta region quickly and accurately.
Data Dependencies in Database with Incomplete Information
Zhang Yan,He Jichao
计算机科学技术学报 , 1988,
Abstract: To get more meaning of incomplete information,a predicate way is proposed torepresent the nulls.The concepts of functional and multivalued dependencies areextended in the environment which allows nulls in a database relation.The inferencerules which can be applied to the extended dependencies are investigated.Finally it isshown that the rules are complete for the family of extended functional and multivalueddependencies.
Integrin Beta 1 Suppresses Multilayering of a Simple Epithelium
Jichao Chen, Mark A. Krasnow
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0052886
Abstract: Epithelia are classified as either simple, a single cell layer thick, or stratified (multilayered). Stratified epithelia arise from simple epithelia during development, and transcription factor p63 functions as a key positive regulator of epidermal stratification. Here we show that deletion of integrin beta 1 (Itgb1) in the developing mouse airway epithelium abrogates airway branching and converts this monolayer epithelium into a multilayer epithelium with more than 10 extra layers. Mutant lung epithelial cells change mitotic spindle orientation to seed outer layers, and cells in different layers become molecularly and functionally distinct, hallmarks of normal stratification. However, mutant lung epithelial cells do not activate p63 and do not switch to the stratified keratin profile of epidermal cells. These data, together with previous data implicating Itgb1 in regulation of epidermal stratification, suggest that the simple-versus-stratified developmental decision may involve not only stratification inducers like p63 but suppressors like Itgb1 that prevent simple epithelia from inappropriately activating key steps in the stratification program.
Oscillation Criteria for a Class of Second-Order Nonlinear Differential Equations with Damping Term
Zigen Ouyang,Jichao Zhong,Shuliang Zou
Abstract and Applied Analysis , 2009, DOI: 10.1155/2009/897058
Abstract: A class of second-order nonlinear differential equations with damping term(()|()|?1())
Crack spacing of unsaturated soils in the critical state
JiChao Sun,GuangQian Wang,QiCheng Sun
Chinese Science Bulletin , 2009, DOI: 10.1007/s11434-009-0319-8
Abstract: The cracking mechanism of unsaturated soils due to evaporation is poorly understood, and the magnitude of crack spacing is usually hard to estimate. In this work, cracks were postulated to occur succedently rather than simultaneously, that is, secondary cracks appear after primary cracks as evaporation continues. Formulae of the secondary crack spacing and secondary trend crack spacing were then derived after stress analysis. The calculated spacing values were consistent with the published experimental data. Meanwhile, the effect of the Poisson ratio on the crack spacing was analyzed, which showed that the magnitude of crack spacing was proportional to the Poisson ratio in the range of [0.30, 0.35].
Crack spacing of unsaturated soils in the critical state

JiChao Sun,GuangQian Wang,QiCheng Sun,

科学通报(英文版) , 2009,
Abstract: The cracking mechanism of unsaturated soils due to evaporation is poorly understood, and the magnitude of crack spacing is usually hard to estimate. In this work, cracks were postulated to occur succedently rather than simultaneously, that is, secondary cracks appear after primary cracks as evaporation continues. Formulae of the secondary crack spacing and secondary trend crack spacing were then derived after stress analysis. The calculated spacing values were consistent with the published experimental data. Meanwhile, the effect of the Poisson ratio on the crack spacing was analyzed, which showed that the magnitude of crack spacing was proportional to the Poisson ratio in the range of 0.30, 0.35]. Supported by the National Natural Science Foundation of China (Grant No. 50709015), China Postdoctoral Science Special Foundation (Grant No. 200801081), China Postdoctoral Science Foundation (Grant No. 20070410531) and National Basic Research Program of China (Grant No. 2007CB714100)
A New Analytical Model for High Heat Flux in Pool Boiling
Guoping Jiang,Boqi Xiao,Jichao Liu
Research Journal of Applied Sciences, Engineering and Technology , 2012,
Abstract: In this study, first the empirical correlations and primary models of Critical Heat Flux (CHF) are introduced, then a new fractal model for critical heat flux is proposed. Algebraic expressions for the fractal dimension of nucleation sites are derived based on the fractal distribution of nucleation sites, which are shown to be a strong function of wall superheat. The new fractal model for critical heat flux is found to be a function of wall superheat. The contact angel of the fluid and the physical properties of the fluid and empirical constant have an important effect on critical heat flux. It turns out that the present model well explains the mechanism on how parameter such as surface wettability influences CHF. The present model shows the surface wettability plays no significant role. The expressions of active nucleation site are applies to CHF which are predicted in the proposed model quantitatively. The predicted critical heat flux from a boiling surface based on the proposed fractal model is compared with existing experimental data. An excellent agreement between the new model predictions and experimental data is found. The validity of the new fractal model is thus verified.
Dimensional Analysis Used For Concrete Damaged Under Impact Loading
Guoping Jiang,WeiJun Tao,Jichao Liu
Research Journal of Applied Sciences, Engineering and Technology , 2012,
Abstract: The dynamic response is analyzed. The numerical simulation method has been used to projectile penetrating concrete for many years. However, most previous research study has concentrated on the cuboids concrete model. Very few studies have been conducted to investigate the penetration process of complex concrete model. In this study, numerical simulations of laboratory tests are conducted to show the penetration process of wedge concrete model. A double scalar damage model based on the concept of continuum damage mechanics is applied to modeling the failure of concrete. In the numerical model of wedge concrete, the wedges with different angles are modeled. By the numerical simulation, the relationship of projectile penetrating into the wedges concrete with different angles are demonstrated.
Female-Biased Symbionts and Tomato Yellow Leaf Curl Virus Infections in Bemisia tabaci
Huifang Guo, Yufeng Qu, Xiangdong Liu, Wanfang Zhong, Jichao Fang
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0084538
Abstract: The female-biased infection of facultative symbionts has been found in Bemisia tabaci; however, whether there are any differences in tomato yellow leaf curl virus (TYLCV) and obligate symbiont infection rates between females and males is unknown. Determining whether such differences exist would be very important for understanding the spread of the plant virus and of the symbionts. We compared both symbiont infection types, including obligate and facultative symbionts, and the rates of TYLCV infection in both sexes in five field populations from Jiangsu Province, China. The obligate symbiont Portiera aleyrodidarum was not found in every whitefly tested. In all tested populations, more females than males were found to harbor P. aleyrodidarum; and more females than males also harbored Hamiltonella defense, the most common facultative symbiont as well as Cardinium. In addition to female-biased symbiont infections, there were also female-biased TYLCV infections, and the infection frequencies of this plant virus in females were higher than those in males. Taken together, these results suggested that both the female-biased symbiont infections and female-biased TYLCV infections promoted the rapid spread of TYLCV in China.
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