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Ecological effect of the plantation of Sabina vulgaris in the Mu Us Sandy Land,China

Journal of Arid Land 2024年第1期16卷 14-28页

作者： NAN Weige DONG Zhibao zhou zhengchao LI Qiang CHEN Guoxiang School of Geography and Tourism Shaanxi Normal UniversityXi'an 710062China Shaanxi Key Laboratory of Ecological Restoration in Shaanbei Mining Area Yulin UniversityYulin 719000China College of Prataculture Gansu Agricultural UniversityLanzhou 730070China

Vegetation restoration through artificial plantation is an effective method to combat desertification,especially in arid and semi-arid areas.This study aimed to explore the ecological effect of the plantation of Sabina vulgaris on soil physical and chemical properties on the southeastern fringe of the Mu Us Sandy Land,China.We collected soil samples from five depth layers(0-20,20-40,40-60,60-80,and 80-100 cm)in the S.vulgaris plantation plots across four plantation ages(4,7,10,and 16 years)in November 2019,and assessed soil physical(soil bulk density,soil porosity,and soil particle size)and chemical(soil organic carbon(SOC),total nitrogen(TN),available nitrogen(AN),available phosphorus(AP),available potassium(AK),cation-exchange capacity(CEC),salinity,p H,and C/N ratio)properties.The results indicated that the soil predominantly consisted of sand particles(94.27%-99.67%),with the remainder being silt and clay.As plantation age increased,silt and very fine sand contents progressively rose.After 16 years of planting,there was a marked reduction in the mean soil particle size.The initial soil fertility was low and declined from 4 to 10 years of planting before witnessing an improvement.Significant positive correlations were observed for the clay,silt,and very fine sand(mean diameter of 0.000-0.100 mm)with SOC,AK,and p H.In contrast,fine sand and medium sand(mean diameter of 0.100-0.500 mm)showed significant negative correlations with these indicators.Our findings ascertain that the plantation of S.vulgaris requires 10 years to effectively act as a windbreak and contribute to sand fixation,and needs 16 years to improve soil physical and chemical properties.Importantly,these improvements were found to be highly beneficial for vegetation restoration in arid and semi-arid areas.This research can offer valuable insights for the protection and restoration of the vegetation ecosystem in the sandy lands in China.

关键词： Sabina vulgaris plantation age soil physical and chemical properties soil particle size soil fertility vegetation restoration Mu Us Sandy Land

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Quantitative assessment of the spatial distribution of^(239+240)Pu inventory derived from global fallout in soils from Asia and Europe

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Journal of Geographical Sciences 2022年第4期32卷 605-616页

作者： CAO Liguo zhou zhengchao WANG Ning XIAO Shun School of Geography and Tourism Shaanxi Normal UniversityXi'an 710119China

Due to the atmospheric nuclear weapon tests carried out,terrestrial environments have been extensively contaminated by global fallout of plutonium(Pu)worldwide.The^(239+240)Pu inventories in soil profiles from undisturbed and flat forest or grasslands(reference sites)mainly from Europe and Asia are considered as important background for evaluating soil erosion.Thus,we conducted a literature survey over an area extending from 2.6°W to 148.9°E and from 53.2°S to 76.6°N,with the purpose of analyzing the spatial distribution of^(239+240)Pu inventories and possible controlling factors.The aim of this work was to derive an empirical model of^(239+240)Pu inventory based on currently available^(239+240)Pu data,precipitation and latitude.The results show that,in general,the latitudinal distribution of^(239+240)Pu inventory was consistent with the UNSCEAR reports.However,the^(239+240)Pu inventories are higher than the UNSCEAR data,especially in the Northern Hemisphere.In addition,close relationships(at the 0.01 significance level)were identified between^(239+240)Pu inventories and annual precipitation and latitude.An empirical formula was therefore developed to estimate^(239+240)Pu inventories in soils based on latitude and precipitation data.However,future research may require more data of measured^(239+240)Pu inventories in soil profiles that can be used to compare,validate and improve upon the accuracy of the inferred empirical equation.

关键词： spatial distribution plutonium global fallout precipitation

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Characteristics and Cause Analysis of Variations in Light Precipitation Events in the Central and Eastern Tibetan Plateau,China,During 1961–2019

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Chinese Geographical Science 2022年第1期32卷 155-173页

作者： LI Kaifang CAO Liguo zhou zhengchao JIAO Lei WANG Ning LIU Ruohan School of Geography and Tourism Shaanxi Normal UniversityXi'an 710119China School of Urban and Rural Planning and Architectural Engineering Shangluo UniversityShangluo 726000China

The Tibetan Plateau(TP)is one of the most sensitive areas and is more susceptible to climate change than other regions in China.The TP also experiences extremely frequent light precipitation events compared to precipitation of other intensities.However,the definition,influencing factors,and characteristics of light precipitation in the TP have not been accurately explained.This study investigated the variation characteristics of light precipitation with intensities(Pre)of 0.1-10.0 mm/d based on climate data from 53 meteorological stations over the central and eastern TP from 1961 to 2019.For detailed analysis,light precipitation events were classified into five grades:G1[0.1-2.0 mm/d),G2[2.0-4.0 mm/d),G3[4.0-6.0 mm/d),G4[6.0-8.0 mm/d),and G5[8.0-10.0 mm/d).The results showed that both the amount of precipitation and number of precipitation days had increased significantly at rates of 4.0-6.0 mm/10 yr and 2.0-4.0 d/10 yr,respectively,and most precipitation events were of low intensity(0.1≤Pre<2.0 mm/d).Light precipitation events mainly occurred in the southeast of the study area,and it showed an increasing trend from the northwest to the southeast.Abrupt changes in light precipitation primarily occurred in the 1980 s.A comprehensive time series analysis using the Mann-Kendall test and Morlet wavelet was performed to characterize the abrupt changes and cycles of light precipitation.During the study period,the main periods of light precipitation corresponded to the 6 yr cycle,with obvious periodic oscillation characteristics,and this cycle coexisted with cycles of other scales.Significant correlations were observed between the amount of light precipitation and temperature over the study area.The findings will enhance our understanding of changes in light precipitation in the TP and provide Scientific basis for the definition of light precipitation in the future.

关键词： light precipitation events spatio-temporal variation period analysis Tibetan Plateau

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Changes in soil organic carbon and nitrogen after 26 years of farmland management on the Loess Plateau of China

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Journal of Arid Land 2015年第6期7卷 806-813页

作者： zhou zhengchao ZHANG Xiaoyan GAN Zhuoting Department of Tourism and Environmental Sciences Shaanxi Normal University Key Laboratory of Disaster Survey and Mechanism Simulation of Shaanxi Province Baoji University of Arts and Sciences

Soil carbon（C） and nitrogen（N） play a crucial role in determining the soil and environmental quality. In this study, we investigated the effects of 26 years（from 1984 to 2010） of farmland management on soil organic carbon（SOC） and soil N in abandoned, wheat（Triticum aestivum L.） non-fertilized, wheat fertilized（mineral fertilizer and organic manure） and alfalfa（Medicago Sativa L.） non-fertilized treatments in a semi-arid region of the Loess Plateau, China. Our results showed that SOC and soil total N contents in the 0–20 cm soil layer increased by 4.29（24.4%） and 1.39 Mg/hm2（100%）, respectively, after the conversion of farmland to alfalfa land. Compared to the wheat non-fertilized treatment, SOC and soil total N contents in the 0–20 cm soil layer increased by 4.64（26.4%） and 1.18 Mg/hm2（85.5%）, respectively, in the wheat fertilized treatment. In addition, we found that the extents of changes in SOC, soil total N and mineral N depended on soil depth were greater in the upper soil layer（0–30 cm） than in the deeper soil layer（30–100 cm） in the alfalfa land or fertilizer-applied wheat land. Fertilizer applied to winter wheat could increase the accumulation rates of SOC and soil total N. SOC concentration had a significant positive correlation with soil total N concentration. Therefore, this study suggested that farmland management, e.g. the conversion of farmland to alfalfa forage land and fertilizer application, could promote the sequestrations of C and N in soils in semi-arid regions.

关键词： soil organic carbon（SOC） soil N fertilizer land use change semi-arid area

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Different Responses of Vegetation to Frozen Ground Degradation in the Source Region of the Yellow River from 1980 to 2018

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Chinese Geographical Science 2020年第4期30卷 557-571页

作者： WANG Rui DONG Zhibao zhou zhengchao School of Geography and Tourism Shaanxi Normal UniversityXi'an 710119China

Frozen ground degradation under a warming climate profoundly influences the growth of alpine vegetation in the source region of the Qinghai-Tibet Plateau.This study investigated spatiotemporal variations in the frozen ground distribution,the active layer thickness(ALT)of permafrost(PF)soil and the soil freeze depth(SFD)in seasonally frozen soil from 1980 to 2018 using the temperature at the top of permafrost(TTOP)model and Stefan equation.We compared the effects of these variations on vegetation growth among different frozen ground types and vegetation types in the source region of the Yellow River(SRYR).The results showed that approximately half of the PF area(20.37%of the SRYR)was projected to degrade into seasonally frozen ground(SFG)during the past four decades;furthermore,the areal average ALT increased by 3.47 cm/yr,and the areal average SFD decreased by 0.93 cm/yr from 1980 to 2018.Accordingly,the growing season Normalized Difference Vegetation Index(NDVI)presented an increasing trend of 0.002/10 yr,and the increase rate and proportion of areas with NDVI increase were largest in the transition zone where PF degraded to SFG(the PF to SFG zone).A correlation analysis indicated that variations in ALT and SFD in the SRYR were significantly correlated with increases of NDVI in the growing season.However,a rapid decrease in SFD(<-1.4 cm/10 yr)could have reduced the soil moisture and,thus,decreased the NDVI.The NDVI for most vegetation types exhibited a significant positive correlation with ALT and a negative correlation with SFD.However,the steppe NDVI exhibited a significant negative correlation with the SFD in the PF to SFG zone but a positive correlation in the SFG zone,which was mainly limited by water condition because of different change rates of the SFD.

关键词： permafrost seasonally frozen ground vegetation dynamics climate change source region of the Yellow River

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Risk Assessment of Heavy Metal Pollution in Sediments of the Fenghe River by the Fuzzy Synthetic Evaluation Model and Multivariate Statistical Methods

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Pedosphere 2016年第3期26卷 326-334页

作者： YANG Yang zhou zhengchao BAI Yanying CAI Yimin CHEN Weiping State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of Sciences College of Environment and Tourism Shaanxi Normal University Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences

Concentrations of heavy metals in 74 sediment samples from the Fenghe River, which originates from the north of the Qinling Mountains and flows through Xi'an, Shaanxi Province, China, were characterized by employing geographic information system(GIS)mapping, fuzzy synthetic assessment, and multivariate statistical analysis to determine the enrichment characteristics of heavy metals as well as their potential risks of pollution to sediments. Al, Cd, and Co were the major pollutants, with a high enrichment factor(EF) value. Heavy metal concentrations from samples near the paper plant were maintained at a high level. Significant enrichment of Al, Ba, Cr, Ni, Pb, and Co was found in the midstream and downstream, while high concentration of Cu occurred in the headwater stream. Based on the cluster and principal component analyses, sediment metals mainly came from the paper plants, agronomic practices, natural sources, and tourism, with a contribution of 51.59%, 23.01%, 14.21%, and 9.88%, respectively. Sediment pollution assessment explored using fuzzy theory based on the entropy method and toxicity coefficient showed that 26, 32, and 11 sites fell into Class III(slightly polluted), Class IV(moderately polluted), and Class V(heavily polluted), respectively, and their scores of membership degree in the polluted level were on the rise, suggesting a relatively high degree of sediment metal pollution in the study area. Closely related to the excessive industrial and agricultural applications, metal pollution in sediment is necessary to be addressed in the Fenghe River.

关键词：模糊综合评价模型污染沉积物重金属污染风险评价多元统计方法重金属浓度地理信息系统多元统计分析

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钚同位素示踪技术在树木年轮中的应用研究进展

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地理科学 2024年第5期44卷 911-916页

作者：曹立国周正朝常晓娇曾小敏王宁陕西师范大学地理科学与旅游学院陕西西安710119 大连市现代农业生产发展服务中心辽宁大连116000

钚(Pu)核素具有极强的辐射毒性和生物毒性,对动植物和人类健康危害巨大,分析Pu同位素在树轮中的水平、迁移规律及其污染历史对于潜在的生态安全和植物毒性评价至关重要。在中国核电事业快速发展的背景下,建立不同区域树轮的Pu同位素背... 详细信息

钚(Pu)核素具有极强的辐射毒性和生物毒性,对动植物和人类健康危害巨大,分析Pu同位素在树轮中的水平、迁移规律及其污染历史对于潜在的生态安全和植物毒性评价至关重要。在中国核电事业快速发展的背景下,建立不同区域树轮的Pu同位素背景数据尤为迫切。为此,本文对目前现存的少量文献资料进行了总结和归纳,首先简要阐述了环境中Pu同位素来源与沉降模式;重点分析了Pu同位素进入树轮的潜在途径,以及Pu同位素在树轮中的径向分布特征及其指示意义;最后,本文强调了建立树轮Pu同位素化学分析测试方法的重要性,及其示踪应用的发展方向,对于促进和拓展树轮Pu同位素示踪研究具有重要现实意义。

关键词： ^(239+240)Pu ^(137)Cs 树木年轮核素示踪

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基于J_(2)摄动项的Runge-Kutta、Hermite数值轨道预报方法

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舰船电子工程 2024年第1期44卷 116-119页

作者：张政超朱峰郭伟锋周磊 63891部队洛阳471000

在给出卫星轨道参数的描述方法的基础上,分析了其坐标变换方法,并通过Matlab进行了编程实现和经过其它坐标变换软件的验证;简析了卫星轨道的预报方法,着重分析了数值法(基于J2项的Runge_Kutta方法、Hermite方法)等的预报,并以STK中HPOP... 详细信息

在给出卫星轨道参数的描述方法的基础上,分析了其坐标变换方法,并通过Matlab进行了编程实现和经过其它坐标变换软件的验证;简析了卫星轨道的预报方法,着重分析了数值法(基于J2项的Runge_Kutta方法、Hermite方法)等的预报,并以STK中HPOP预报结果为真值,对其预测性能进行了仿真分析。

关键词： J2摄动项卫星轨道预报性能仿真

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KT形钢管相贯节点受力性能试验研究

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建筑结构 2024年第12期54卷 28-34页

作者：陈元坤李宏胜熊政超王佳盟朱爱珠周伟伟中南建筑设计院股份有限公司武汉430071 武汉大学土木建筑工程学院武汉430072 华中科技大学土木与水利工程学院武汉430074

依托某户外剧场钢结构顶棚结构设计,首先对其管桁架关键KT形钢管相贯节点进行了足尺模型试验,测试分析了该节点相贯线、主管及支管应变分布规律。试验结果显示,在最大荷载作用下,相贯节点因支管相贯线附近部分屈服而不能继续承载,其余... 详细信息

依托某户外剧场钢结构顶棚结构设计,首先对其管桁架关键KT形钢管相贯节点进行了足尺模型试验,测试分析了该节点相贯线、主管及支管应变分布规律。试验结果显示,在最大荷载作用下,相贯节点因支管相贯线附近部分屈服而不能继续承载,其余位置未屈服,表明支管相贯线附近位置是该相贯节点最薄弱位置。然后运用ANSYS有限元软件建立KT形钢管相贯节点有限元模型,将试验结果与有限元分析结果作对比,验证了有限元模型的准确性。最后通过有限元模拟探讨了增大支管厚度以及增设加劲肋对节点受力性能的影响。有限元分析结果显示,增大支管厚度对其受力性能影响较小;增设加劲肋可以有效降低支管相贯线附近位置的最大应力水平,能有效延缓支管屈服,明显提高管桁架节点的承载力。

关键词：钢管相贯节点足尺模型试验受力性能有限元分析

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医院建筑屋顶停机坪的设计与施工技术研究

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中国医院建筑与装备 2024年第4期25卷 37-42页

作者：田兴周茜马迅熊正朝付鸣罗涵北京城建集团有限责任公司北京100088 北京城建八建设发展有限责任公司北京102218

从北京安贞医院通州院区项目停机坪的钢结构、场道、甲板、锁机栓、标识、安全网安装、通信、助航导航系统、电气设备安装、气象系统、消防设施安装等方面对停机坪的设计和施工技术进行介绍,并从救援效率、安全性、是否受地势影响及国... 详细信息

从北京安贞医院通州院区项目停机坪的钢结构、场道、甲板、锁机栓、标识、安全网安装、通信、助航导航系统、电气设备安装、气象系统、消防设施安装等方面对停机坪的设计和施工技术进行介绍,并从救援效率、安全性、是否受地势影响及国家政策层面对医用停机坪的发展前景进行了展望,侧面印证了对医院建筑屋顶停机坪的设计与施工技术进行研究的必要性。

关键词：医院建筑屋顶停机坪设计施工技术消防航空医疗救援

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