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Wang L.,Tianjin Institute of Surveying and Mapping | Li D.C.,Hebei University of Technology
Materials Science Forum | Year: 2016

Solubilities of the quaternary system containing lithium, sodium, magnesium and chloride at 273.15 K were calculated using Pitzer ion-interaction model and its extended HW model. The values of the Pitzer single-salt parameters β(0), β(1), β(2) and Cϕ for LiCl, NaCl, and MgCl2, the mixed ion-interaction parameters θLi,Mg, θLi,Na, θNa,Mg, ψLi,Mg,Cl, ψLi,Na,Cl and ψNa,Mg,Cl, and the Debye–Hückel parameter Aϕ in the quaternary system at 273.15K were derived. Based on the Jänecke indexes, the phase diagram was plotted. This study affords the necessary parameters for solubility predictions of complicated systems and establishes a theoretical basis for the separation of these valuable minerals from salt lake brine. © 2016 Trans Tech Publications, Switzerland.

PubMed | China Earthquake Administration, Hohai University, Tianjin Institute of Surveying and Mapping, U.S. Center for Disease Control and Prevention and 2 more.
Type: Journal Article | Journal: International journal of environmental research and public health | Year: 2016

Hemorrhagic fever with renal syndrome (HFRS) is considered a globally distributed infectious disease which results in many deaths annually in Hubei Province, China. In order to conduct a better analysis and accurately predict HFRS incidence in Hubei Province, a new model named Seasonal Difference-Geographically and Temporally Weighted Regression (SD-GTWR) was constructed. The SD-GTWR model, which integrates the analysis and relationship of seasonal difference, spatial and temporal characteristics of HFRS (HFRS was characterized by spatiotemporal heterogeneity and it is seasonally distributed), was designed to illustrate the latent relationships between the spatio-temporal pattern of the HFRS epidemic and its influencing factors. Experiments from the study demonstrated that SD-GTWR model is superior to traditional models such as GWR- based models in terms of the efficiency and the ability of providing influencing factor analysis.

PubMed | China Earthquake Administration, Hohai University, Tianjin Institute of Surveying and Mapping, U.S. Center for Disease Control and Prevention and 2 more.
Type: Journal Article | Journal: PloS one | Year: 2016

Hemorrhagic Fever with Renal Syndrome (HFRS) is considered as a globally distributed infectious disease, which results in many deaths annually in Hubei Province, China. The outbreak of HFRS is usually characterized with spatio-temporal heterogeneity and is seasonally distributed. Further, it might also be impacted by the influencing factors such as socio-economic and geographical environment. To better understand and predict the outbreak of HFRS in the Hubei Province, the spatio-temporal pattern and influencing factors were investigated in this study. Morans I Index value was adopted in spatial global autocorrelation analysis to identify the overall spatio-temporal pattern of HFRS outbreak. Kulldorff scan statistical analysis was performed to further identify the changing trends of the clustering patterns of HFRS outbreak. Spearmans rank correlation analysis was used to explore the possible influencing factors on HFRS epidemics such as climate and geographic. The results demonstrated that HFRS outbreak in Hubei Province decreased from 2005 to 2012 in general while increasing slightly from 2012 to 2014. The spatial and temporal scan statistical analysis indicated that HFRS epidemic was temporally clustered in summer and autumn from 2005 to 2014 except 2008 and 2011. The seasonal epidemic pattern of HFRS in Hubei Province was characterized by a bimodal pattern (March to May and September to November) while peaks often occurring in the spring time. SEOV-type HFRS was presumed to influence more on the total number of HFRS incidence than HTNV-type HFRS do. The average humidity and human population density were the main influencing factors during these years. HFRS outbreaks were more in plains than in other areas of Hubei Province. We did not find that whether the terrain of the wetland (water system) plays a significant role in the outbreak of HFRS incidence. With a better understanding of rodent infection rate, socio-economic status and ecological environment characteristics, this study may help to reduce the outbreak of HFRS disease.

Wei E.,Wuhan University | Jin S.,Chinese Academy of Sciences | Zhang Q.,Wuhan University | Zhang Q.,Tianjin Institute of Surveying and Mapping | And 3 more authors.
Advances in Space Research | Year: 2013

Autonomous navigation of Mars probe is a main challenge due to the lack of dense ground tracking network measurements. In this paper, autonomous navigation of the Mars probe Orbits is investigated using the X-ray pulsars. A group of X-ray pulsars with high ranging accuracy are selected based on their properties and an adaptive extended Kalman filter is developed to incorporate the Mars probe dynamics and pulsar-based ranging measurements. Results of numerical experiment show that the three-dimensional positioning accuracy can achieve 750m in X-axis, 220m in Y-axis and 230m in Z-axis, which is much better than the positioning results by current Very Long Baseline Interferometry (VLBI) or Doppler observations with the accuracy of 150 km or several kilometers, respectively. © 2012 COSPAR. Published by Elsevier Ltd. All rights reserved.

PubMed | Tianjin Institute of Surveying and Mapping, Chinese Academy of Surveying and Mapping and Wuhan University
Type: Journal Article | Journal: Sensors (Basel, Switzerland) | Year: 2016

Synthetic Aperture Radar Interferometry (InSAR) techniques are increasingly applied for monitoring land subsidence. The advantages of InSAR include high accuracy and the ability to cover large areas; nevertheless, research validating the use of InSAR on building deformation is limited. In this paper, we test the monitoring capability of the InSAR in experiments using two landmark buildings; the Bohai Building and the China Theater, located in Tianjin, China. They were selected as real examples to compare InSAR and leveling approaches for building deformation. Ten TerraSAR-X images spanning half a year were used in Permanent Scatterer InSAR processing. These extracted InSAR results were processed considering the diversity in both direction and spatial distribution, and were compared with true leveling values in both Ordinary Least Squares (OLS) regression and measurement of error analyses. The detailed experimental results for the Bohai Building and the China Theater showed a high correlation between InSAR results and the leveling values. At the same time, the two Root Mean Square Error (RMSE) indexes had values of approximately 1 mm. These analyses show that a millimeter level of accuracy can be achieved by means of InSAR technique when measuring building deformation. We discuss the differences in accuracy between OLS regression and measurement of error analyses, and compare the accuracy index of leveling in order to propose InSAR accuracy levels appropriate for monitoring buildings deformation. After assessing the advantages and limitations of InSAR techniques in monitoring buildings, further applications are evaluated.

Luo Q.,Tianjin University | Perissin D.,Purdue University | Zhang Y.,CAS National Astronomical Observatories | Jia Y.,Tianjin Institute of Surveying and Mapping
Remote Sensing | Year: 2014

When synthetic aperture radar interferometry (InSAR) technology is applied in the monitoring of land subsidence, the sensor band plays an important role. An X-band SAR system as TerraSAR-X (TSX) provides high resolution and short revisit time, but it has no capability of global coverage. On the other side, an L-band sensor as Advanced Land Observing Satellite-Phased Array L-band Synthetic Aperture Radar (ALOS-PALSAR) has global coverage and it produces highly coherent interferograms, but it provides much less details in time and space. The characteristics of these two satellites from different bands can be regarded as complementary. In this paper, we firstly present a possible strategy for X-band optimized acquisition planning combining with L-band. More importantly, we also present the multi-temporal InSAR (MT-InSAR) analysis results from 23 ALOS-PALSAR images and 37 TSX data, which show the complementarity of L- and X-band allows measuring deformations both in urban and non-urban areas. Furthermore, the validation between MT-INSAR and leveling/GPS has been carried out. The combination analysis of L- and X-band MT-InSAR results effectively avoids the limitation of X-band, providing a way to define the shape and the borderline of subsiding center and helps us to understand the subsidence mechanism. Finally, the geological interpretation of the detected subsidence center is given. © 2014 by the authors.

Fan Y.,Tianjin Institute of Surveying and Mapping | Zhou Y.,Tianjin Institute of Surveying and Mapping
Journal of Geomatics | Year: 2014

As an important part of the city surveying, section surveying plays an important role in public engineering survey. Section drawing is an important achievement here. Generally speaking, section drawing has special request, the course of which is complex and hard. Embarking from the actual work, this paper designs and writes a program for improving the work efficiency.

Liu H.,Tianjin Institute of Surveying and Mapping | Mei L.,Tianjin Institute of Surveying and Mapping
Journal of Geomatics | Year: 2014

Data recording format characteristics of Trimble, Leica and South were analyzed. Accordingly, based on the C# programming language, the software system was developed with the functions of data format conversion and data adjustment processing. With the actual engineering data, commercial software calculation results were compared to verify the correctness of the software.

Hu Q.,Tianjin Institute of Surveying and Mapping | Min X.,Tianjin Institute of Surveying and Mapping
Journal of Geomatics | Year: 2014

In this paper, the significance of management and using pipeline information with WebGIS are expained. And the design of WebGIS for urban pipeline based on ArcGIS and Silverlight was offered. And then, using ArcGIS API for Silverlight and Silverlight SDK, a prototype, the managing system of urban pipeline information for Jinghai County, Tianjin City, is implemented.

Luo Q.,Chinese University of Hong Kong | Perissin D.,Chinese University of Hong Kong | Lin H.,Chinese University of Hong Kong | Zhang Y.,Chinese University of Hong Kong | Wang W.,Tianjin Institute of Surveying and Mapping
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2014

This paper illustrates the first wide area study over Tianjin suburbs of China using persistent scatterers interferometry (PSI) technique for ground subsidence monitoring via high-resolution TerraSAR-X (TSX) SAR data. The deformation rate and the displacement history of the subsiding areas from April 29, 2009 to November 11, 2011 have been reconstructed. The results demonstrate the capability of applying PSI technique to high-resolution SAR time series imageries for monitoring of the subsidence of multiple towns and large-scale man-made linear features (LMLFs) such as railways, highways, and power lines. The comprehensive uncertainties were analyzed between PSI results and ground-leveling data whose densities are very different in both spatial and temporal domains. The overall results show a good agreement with each other. We also found that the underground water extraction and lithological character are the two important potential explanations to the location and shape of the subsiding centers. © 2013 IEEE.

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