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| 1 | An experimental study of salt expansion in sodium saline soils under transient conditions显示文摘Salt expansion in sulfate saline soils that are widely distributed in northwestern China causes serious infrastructural damages under low-temperature conditions. However, the mechanism of salt expansion under low temperatures is not clear. In this study, we conducted a series of cooling experiments combined with salt crystallization to study this mechanism, and employed an ionic model to calculate the supersaturation ratio of the solution. During the experiments, the strength and the process of salt expansion were examined under different cooling rates and various crystal morphologies. The relationship between temperature and supersaturation ratio under transient conditions was also considered. Results indicate that the initial supersaturation ratio of a sodium sulfate solution is closely related to environmental conditions, and that this ratio decreases with slowing the cooling rates and stabilizing the crystal forms. Higher initial supersaturation ratios lead to an increased non-steady-state zone, resulting in less salt expansion. On the other hand, chloride ion content has a distinct influence on the crystallization supersaturation ratio of the sodium sulfate solution, and higher chloride ion content can inhibit salt expansion in sodium saline soils. These findings help explain salt expansion mechanisms in complex conditions such as seasonally frozen soils, and thus help search for improved methods of preventing salt expansion in sulfate saline soils. | WAN Xusheng YOU Zhemin WEN Haiyan William CROSSLEY | 2017 | Journal of Arid Land2017，9，6： | 9 |
| 2 | Periodical characteristics of baseflow in the source region of the Yangtze River显示文摘Baseflow,which represents the drainage of groundwater aquifers,is an essential component of runoff in hydrological basins.In the source region of the Yangtze River,the change of baseflow typically reflects the interactions between groundwater system and climatic factors in cold and arid areas.With modified Kalinen separation method,annual baseflow between 1957 and 2009 in this region was estimated and calculated.In comparison with the inner-annual variations of total streamflow,baseflow showed a weaker fluctuation.Before the 1980s,it was in a steady state;and after then,it demonstrated dramatic variations and large amplitudes.Based on the calculation results of baseflow,the real Morlet wavelet method was applied to reveal the periodical characteristics of baseflow as well as the precipitation and air temperature in the study area.It was found that annual baseflow has a 43-year trend as well as a 21-year period and a 7-year period.The 21-year period is most significant,with its wavelet coefficient having the largest fluctuation and amplitude.Summation of wavelet coefficients on these periods exhibits a similar change pattern with respect to that of annual baseflow.The summation curve takes a'W'shape,which means that the baseflow follows a four-stage sequence of descending–ascending–descending–ascending.As analyzed,the relationship among baseflow,precipitation and temperature is implied in the correlation between their normalized wavelet coefficients at different temporal scales.By the significant positive linear correlations both between precipitation and baseflow(correlation coefficient is 0.98)and between temperature and baseflow(correlation coefficient is 0.90)for the 43-year wavelet coefficients,it is suggested that the long-term increasing trends of precipitation and air temperature will lead to an increasing trend of baseflow.For wavelet coefficients of 21-year and 7-year periods,the positive linear correlation between precipitation and baseflow is significant.However,the correlation between air temperature and baseflow is not so evident,especially for the 21-year period.As a conclusion, correlation analysis with normalized wavelet coefficients showed that the change of annual baseflow was contributed mostly by the change of precipitation and secondly by the change of temperature. | KaiZhu QIAN Li WAN XuSheng WANG JingJing LV SiHai LIANG | 2012 | Journal of Arid Land2012，4，2： | 7 |
| 3 | Groundwater contributions in water-salt balances of the lakes in the Badain Jaran Desert,China显示文摘Groundwater-fed lakes are essential for the ecology in arid and semiarid regions.As a typical arid region,the Badain Jaran Desert (BJD) is famous in the world for the presence of a large number of groundwater-fed saline lakes among the mega dunes.Based on the up to date geological surveys and observations,this study analyzed the groundwater contributions in water-salt balances of the lakes in the desert.We found different types of springs,including the sublacustrine springs that indicate an upward flow of groundwater under the lakebed.A simplified water balance model was developed to analyze the seasonal variations of water level in the Sumu Barun Jaran Lake,which revealed an approximately steady groundwater discharge in the lake and explained why the amplitude of seasonal changes in lake level is less than 0.5 m.In addition,a salt balance model was developed to evaluate the salt accumulations in the groundwater-fed lakes.The relative salt accumulation time is 800–7,000 years in typical saline lakes,which were estimated from the concentration of Cl-,indicating a long history evolution for the lakes in the BJD.Further researches are recommended to provide comprehensive investigations on the interactions between the lakes and groundwater in the BJD. | GONG Yanping WANG Xusheng HU B Xiao ZHOU Yangxiao HAO Chunbo WAN Li | 2016 | Journal of Arid Land2016，8，5： | 7 |
| 4 | Permeability Heterogeneity in a Fractured Sandstone-Mudstone Rock Mass in Xiaolangdi Dam Site,Central China显示文摘Heterogeneity of permeability in fractured media is a hot research topic in hydrogeology. Numerous approaches have been proposed to characterize heterogeneity in the last several decades. However,little attention has been paid to correlate permeability heterogeneity with geological information.In the present study,several causes of permeability heterogeneity,that is,lithology, tectonism,and depth,are identified.The unit absorption values(denoted asω),which are results obtained from the packer test,are employed to represent permeability.The variability of permeability in sandstone-mudstone is so significant that the value of unit absorptions span 3-4 orders of magnitude at any depth with several test sections.By declustering,it has been found that under a similar tectonic history,the means of permeability differ greatly at different formations as a result of different mudrock contents.It has also been found that in the same formation,permeability can be significantly increased as a result of faulting.The well-known phenomenon,the decrease in permeability with depth,is found to be caused by the fractures in the rock mass,and the relationship between permeability and depth can be established in the form of logω-logd.After subtracting the trend ofωwith absolute depth,the mean of the residual value at each relative depth can be well correlated with the distribution of mudstone. The methods proposed in this paper can be utilized to research in similar study areas. | JIANG Xiaowei WAN Li WANG Xusheng KANG Aibin HUANG Jun HUANG Guoxing | 2009 | Acta Geologica Sinica(English Edition)2009，83，5： | 4 |
| 5 | Steady-State Discharge into Tunnels in Formations with Random Variability and Depth-Decaying Trend of Hydraulic Conductivity 显示文摘 | JIANG Xiaowen WAN Li YEH Tian-Chyi Jim WANG Xusheng XU Liang | 2010 | Journal of Hydrology2010，，387： | 1 |
| 6 | Seismic Liquefaction Resistance Based on Strain Energy Concept Considering Fine Content Value Effect and Performance Parametric Sensitivity Analysis显示文摘Liquefaction is one of the most destructive phenomena caused by earthquakes,which has been studied in the issues of potential,triggering and hazard analysis.The strain energy approach is a common method to investigate liquefaction potential.In this study,two Artificial Neural Network(ANN)models were developed to estimate the liquefaction resistance of sandy soil based on the capacity strain energy concept(W)by using laboratory test data.A large database was collected from the literature.One group of the dataset was utilized for validating the process in order to prevent overtraining the presented model.To investigate the complex influence of fine content(FC)on liquefaction resistance,according to previous studies,the second database was arranged by samples with FC of less than 28%and was used to train the second ANN model.Then,two presented ANN models in this study,in addition to four extra available models,were applied to an additional 20 new samples for comparing their results to show the capability and accuracy of the presented models herein.Furthermore,a parametric sensitivity analysis was performed through Monte Carlo Simulation(MCS)to evaluate the effects of parameters and their uncertainties on the liquefaction resistance of soils.According to the results,the developed models provide a higher accuracy prediction performance than the previously publishedmodels.The sensitivity analysis illustrated that the uncertainties of grading parameters significantly affect the liquefaction resistance of soils. | Nima Pirhadi Xusheng Wan Jianguo Lu Jilei Hu Mahmood Ahmad Farzaneh Tahmoorian | 2023 | Computer Modeling in Engineering & Sciences2023，，4： | 1 |
| 7 | Monodisperse micro-spherical Sr_(2-z)Mg_(1+y)Y_(z)Al_(22-x)O_(36):xMn^(4+)red phosphors显示文摘With narrow red photoluminescence (PL) bands, tetravalent Mn^(4+) doped phosphors show promising prospect in commercial application to effectively expand color gamut of phosphor converted LED displays. Here, we report a type of Sr_(2-z)Mg_(1+y)Y_(z)Al_(22-x)O_(36):xMn^(4+) phosphors with regular cage-like micro-spherical morphologies. The micron size spherical precursors were synthesized with a propylene oxide (PO) driven fast sol–gel method. The cage -like spherical morphology is beneficial to efficiently trapping much incident light to enhance the PL of the phosphors. Being calcined at 1300 ℃, Sr_(2)MgAl_(21.978)O_(36):0.022Mn^(4+) only exhibits the internal quantum efficiency (IQE) of 24.91%. With the Mg^(2+)-Mn^(4+) codoping and Y^(3+)/Sr^(2+) substituting strategies, to fulfill charge balance and produce John-Teller distortion, IQE of Sr_(2-z)Mg_(1+y)Y_(z)Al_(22-x)O_(36):xMn^(4+) can be further improved up to 36.45%. The CIE color coordinates of Sr_(2-z)Mg_(1+y)Y_(z)Al_(22-x)O_(36):xMn^(4+) under near ultraviolet excitation can be stably fixed to (0.723, 0.227) at deep red region. It thus finds a potential application as pc-LED display with much broader color gamut than that of the NTSC standard. Therefore, Sr_(2-z)Mg_(1+y)Y_(z)Al_(22-x)O_(36):xMn^(4+) micron size spheres can be employed as promising red phosphors for high performance LED displays. | Jiannan Jia Mengting He Jun Wan Yuting Zhang Hai Guo Xianping Fan Xusheng Qiao Shiguo Chen | 2022 | Journal of Rare Earths2022，40，4： | 1 |
| 8 | Geological Causes of Permeability Heterogeneity in a Fractured Sandstone-Mudstone Rock Mass in the Xiaolangdi Dam Site,Central China显示文摘Heterogeneity of permeability in fractured media is a hot research topic in hydrogeology and numerous approaches had been proposed to characterize heterogeneity in the past several decades.However。 | Xiaowei Jiang~1,Wan Li~1,Xusheng Wang~1,Aibin Kang~1,Jun Huang~(2,3),Guoxing Huang~1 1.School of Water Resources & Environment,China University of Geosciences(Beijing),Beijing 100083,China. 2.Research Center of Tunneling and Underground Engineering,Beijing Jiaotong University,Beijing 100044,China 3.China Highway Planning and Design Institute(HPDI) Consultants,INC,Beijing 100010,China | 2009 | 地学前缘2009，16，S1： | 0 |
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