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| 1 | Attenuation of arsenic in a karst subterranean stream and correlation with geochemical factors: A case study at Lihu,South China显示文摘Arsenic(As) pollutants generated by human activities in karst areas flow into subterranean streams and contaminate groundwater easily because of the unique hydrogeological characteristics of karst areas. To elucidate the reaction mechanisms of arsenic in karst subterranean streams, physical–chemical analysis was conducted by an inductively coupled plasma mass spectrometer and an X-ray fluorescence spectrometer. The results show that inorganic species account for most of the total arsenic, whereas organic arsenic is not detected or occurs in infinitesimal amounts. As(III) accounts for 51.0% ± 9.9% of the total inorganic arsenic. Arsenic attenuation occurs and the attenuation rates of total As,As(III) and As(V) in the Lihu subterranean stream are 51%, 36% and 59%, respectively. To fully explain the main geochemical factors influencing arsenic attenuation, SPSS 13.0 and CANOCO 4.5 bundled with Cano Draw for Windows were used for simple statistical analysis and redundancy analysis(RDA). Eight main factors, i.e., sediment iron(SFe), sediment aluminum(SAl), sediment calcium(SCa), sediment organic matter(SOM), sediment manganese(SMn), water calcium(WCa2+), water magnesium(WMg2+), and water bicarbonate ion(WHCO3-) were extracted from thirteen indicators. Their impacts on arsenic content rank as: SFe > SCa > WCa2+> SAl > WHCO3-> SMn > SOM > WMg2+. Of these factors, SFe, SAl, SCa, SOM, SMn, WMg2+and WCa2+promote arsenic attenuation, whereas WHCO3-inhibits it. Further investigation revealed that the redox potential(Eh) and p H are adverse to arsenic removal. The dramatic distinction between karst and non-karst terrain is that calcium and bicarbonate are the primary factors influencing arsenic migration in karst areas due to the high calcium concentration and alkalinity of karst water. | Liankai Zhang Hui Yang Jiansheng Tang Xiaoqun Qin Au Yik Yu | 2014 | Journal of Environmental Sciences2014，26，11： | 5 |
| 2 | A Novel Orthogonal LoRa Multiple Access Algorithm for Satellite Internet of Things显示文摘In recent years,LoRa has been extensively researched in the satellite Internet of Things(IoT).However,the multiple access technology of LoRa is still one of the bottlenecks of satellite IoT.To improve the multiple access performance of LoRa satellite IoT,based on the orthogonality of LoRa symbols in the fractional domain,this paper proposes a low complexity Orthogonal LoRa Multiple Access(OLMA)algorithm for multiple LoRa users occupying the same frequency bandwidth.The algorithm introduces the address code to divide the fractional bandwidth into multiple parts,and the OLMA users with different address codes occupy different parts to transmit the information code,thus avoiding mutual interference caused by collisions in the same frequency bandwidth.The multiple access capability of OLMA can be flexibly configured only by simply adjusting the length of the address code according to the actual application requirements of data transmission.Theoretical analysis and simulation results show that the OLMA algorithm can greatly improve the multiple access capability and the total transmission bit rate of LoRa IoT without changing the existing LoRa modulation parameters and process. | Chengwen Zhang Liankai Wang Libin Jiao Shipeng Wang Jun Shi Jia Yue | 2022 | China Communications2022，19，3： | 4 |
| 3 | Comparative study of carbonic anhydrase activity in waters among different geological eco-environments of Yangtze River basin and its ecological significance显示文摘This study provides the presence of carbonic anhydrase(CA) activity in waters of the Yangtze River basin, China, as well as the correlation of CA activity with HCO-3 concentration and CO_2 sink flux. Different degrees of CA activity could be detected in almost all of the water samples from different geological eco-environments in all four seasons. The CA activity of water samples from karst areas was significantly higher than from non-karst areas(PP3-concentration(r = 0.672, P2 sink flux(r = 0.602, P = 0.076) in karst areas. This suggests that CA in waters might have a promoting effect on carbon sinks for atmospheric CO_2 in karst river basins. In conditions of similar geological type, higher CA activity was generally detected in water samples taken from areas that exhibited better eco-environments, implying that the CA activity index of waters could be used as an indicator for monitoring ecological environments and protection of river basins. These findings suggest that the role of CA in waters in the karst carbon sink potential of river basins is worthy of further in-depth studies. | Sila Onesmus Nzung'a Weizhi Pan Taiming Shen Wei Li Xiaoqun Qin Chenwei Wang Liankai Zhang Longjiang Yu | 2018 | Journal of Environmental Sciences2018，30，4： | 3 |
| 4 | Metal-organic Chemical Vapor Deposition of GaSb/GaAs Quantum Dots: the Dependence of the Morphology on Growth Temperature and Vapour V/Ⅲ Ratio显示文摘 | YANG Haoyu LIU Renjun LU You WANG Liankai LI Tiantian LI Guoxing ZHANG Yuantao ZHANG Baolin | 2014 | Chemical Research in Chinese Universities2014，30，1： | 2 |
| 5 | Pool Sizes and Turnover of Soil Organic Carbon of Farmland Soil in Karst Area of Guilin显示文摘The three-pool and first-order model separates the mineralizable organic carbon into active,slow,and passive carbon pools.This paper used the model and decomposition curves of the soil organic carbon to fit the active pool and its decomposition rate,slow pool and its decomposition rate.The results showed that the size of the active pool from different profiles accounted for 2.09%-3.08% of the total soil organic carbon and the mean residue time was 3.57-17.21 days.And the size of the slow pool accounted for 3.19%-43.55% and the mean residue time was 1.12-4.94 years.Acid hydrolysis(6M HCl) was used to fractionate the passive organic carbon,which accounted for 50.83%-94.44% of the total soil organic carbon. | YANG Hui CAO Jianhua ZHANG Liankai HOU Yanlin MAO Lifeng | 2011 | Journal of Northeast Agricultural University(English Edition)2011，18，1： | 2 |
| 6 | Paleogene geological framework and tectonic evolution of the central anticlinal zone in Lufeng 13 sag,Pearl River Mouth Basin显示文摘The Paleogene geological framework and evolution process in the central anticline zone in the Lufeng 13 sag in Pearl River Mouth Basin is well analyzed through seismic data and drilling data,and control of tectonic evolution on hydrocarbon accumulation is also discussed.The results show that the central anticline zone in the Lufeng 13 sag develops the upper deformation layer and lower deformation layer.The“arched graben system”is developed in the upper deformation layer,and the magmatic diapir structure and flowing deformation of plastic strata is developed in the lower deformation layer.The evolution process of the central anticline zone can be divided into four stages,i.e.fault block uplifting stage,prototype stage,strengthening stage and finalization stage.The geological framework and tectonic evolution of the central anticline zone control Paleogene hydrocarbon accumulation.The Paleogene twolayer geological framework is favorable for development of structural traps and composite traps;the paleostructure highs are the direction of hydrocarbon migration,and the gravitational gliding faults are the main carrier bed for vertical hydrocarbon migration;the tectonic uplift is a key factor for reservoir diagenesis improvement and preservation of primary pores,and also controls distribution of high-quality reservoirs. | Xudong Wang Xiangtao Zhang Heming Lin Xiaoming Que Yong He Liankai Jia Zhangbo Xiao Min Li | 2019 | Petroleum Research2019，4，3： | 2 |
| 7 | THREE DIMENSIONAL MULTIPHASE COMPUTATIONAL FLUID DYNAMICS ANALYSIS OF VENTILATED SUPERCAVITATION显示文摘For some vehicles travelling through water,it is advantageous to cover the vehicle in a supercavity for the sake of reducing the drag acting on it. The method of artificial ventilation is most effective for generating and dominating the supercavity. This paper focuses on the numerical simulation of flow field around three dimensional body. The method is based on the multiphase computational fluid dynamics (CFD) model combined with the turbulence model and the full cavity model. The flow field of cavity is simulated by solving the compressible Navier-Stokes equations. The fundamental similarity parameters of ventilated supercavitaty flows that include cavitation number,Froude number,ventilation rate and drag coefficient are all investigated numerically in the case of steady flow and gravity field. We discuss the following simulations results in section 3: The variations of the cavitation number and the supercavity's relative diameter with ventilation rate (subtopic 3.1); The drag coefficient versus the cavitation number (subtopic 3.2); Deformation of supercavity axis caused by gravitational effect for three different fixed Froude numbers-2.8,3.4,4.2 (subtopic 3.3). In subtopic 3.2,we give the comparison results of the drag reduction ratio among numerical simulation and experiment conducted in hydrodynamic tunnel and towing tank respectively. In subtopic 3.3,we summarize our discussion of gravitational effect on the axis deformation of supercavity as follows: In the case of smaller Froude number,the inclination of the cavity axis increases monotonously with increasing horizontal length,and reaches its maximal value at the end of supercavity; This deformation can be almost completely negligible when the Froude number Fr>7. The comparisons with the experimental data in the hydrodynamic tunnel and the towing tank indicate that the present method is effective for predicting the flows around ventilated supercavity; that the numerical results is in good agreement with the experimental ones and that the maximal value of the drag reduction ratio can reach 88% compared with that the condition of fully-wetted. | YANG Wugang ZHANG Yuwen YANG Jie ZUO Liankai | 2008 | Chinese Journal of Mechanical Engineering2008，21，1： | 1 |
| 8 | Effeeted of Different Land Use Types On Soil Organic Carbon and Carbon Management Index in Karst Area显示文摘 | YANG Hui ZHANG liankai CAO Jianhua | 2010 | Agricultural Science & Technology2010，11，910： | 1 |
| 9 | Spatio-temporal variation of soil CO_(2) concentration in Loess Area of northwestern Shanxi Province,China显示文摘CO_(2) released by soil serves as an important link between terrestrial ecosystems and atmospheric CO_(2), whose small chang‐es may significantly affect the global carbon cycle. In order to reveal the spatio-temporal variations of CO_(2) concentrations in deep loess, this paper takes Qingliangsi Gully watershed in northwestern Shanxi Province, China as an example to sys‐tematically study soil CO_(2)concentration and its spatio-temporal variations and carbon sink significance under different watershed locations and different land use types. Results show that: (1) The release potential of the loess soil is larger in the depth range of 2 m, which is much more likely to be the CO_(2) release area. (2) Grassland and forest are more advanta‐geous in terms of soil microbial activity and soil carbon reserve compared with farmland. In addition, the change of land use type from farmland to grassland can increase soil organic carbon reserve, which is of far-reaching significance to the global carbon cycle. This is especially true in an area like the Loess Plateau with densely covered hills, gullies, and serious soil erosion in an area of 64×104 km2. (3) In the study area, the diurnal concentration of soil CO_(2) at different depths shows a weak 'high-low-high-low' trend from 08:00 to 07:00 next day;and in deep soil it has a lag time compared with the daily change of temperature, generally about 4−12 h, which may be caused largely by the more compact loess structure. It is worth pointing out that the Loess Plateau in China, with a thickness of the loess of tens to hundreds of meters, has the most abundant soil resources in the world, and also stores a large amount of terrestrial soil carbon, which carries the hope of promoting the research of global carbon cycle. | TianJie Shao ZhiPing Xu LianKai Zhang RuoJin Wang JunJie Niu MingYu Shao | 2022 | Research in Cold and Arid Regions2022，14，3： | 0 |
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