岩溶区不同微地形芒果园土壤肥力综合评价

【目的】采用不同评价方法对不同微地形芒果园的土壤肥力特征进行评价,为岩溶区芒果园土壤肥力的精准评价提供参考。【方法】在广西百色市田阳区典型岩溶区芒果园设置洼地、过渡带、坡地、垭口4种微地形样地,筛选出10项土壤化学指标作为评价指标,应用主成分分析法、模糊数学法、改进的内梅罗指数法、基于粗糙集理论的土壤肥力评价法对不同微地形进行土壤肥力评价,分析不同肥力评价方法评价结果间的差异,对肥力评价指数与产量进行线性拟合,通过冗余分析探索微地形及环境因子对土壤综合肥力的影响。【结果】不同微地形主成分土壤肥力指数表现为坡地(0.87,肥力极高)>垭口(0.59,肥力中等)>过渡带(0.48,肥力中等)>洼地(0.39,肥力低);模糊数学土壤肥力指数表明不同微地形土壤肥力均在高水平以上(0.68~0.82);内梅罗土壤肥力指数表明不同微地形土壤肥力均在中等水平以下(0.26~0.46);粗糙集理论土壤肥力指数表现为坡地(0.67,肥力高)>垭口(0.50,肥力中等)>过渡带(0.37,肥力低)>洼地(0.35,肥力低),该评价结果相对准确且与产量线性拟合度最高。冗余分析结果表明,地形因子对土壤肥力的解释量为34.15%,环境因子解释量为23.30%。【结论】综合不同评价方法的评价结果,不同微地形芒果园的土壤肥力基本表现为坡地>垭口>过渡带>洼地;基于粗糙集理论将3种常规肥力评价方法进行综合评价的结果相对准确,对不同微地形肥力等级区分效果较好。不同微地形土壤肥力差异受地形因子及环境因子共同影响,其中地形因子影响较大。

异构多核运动控制器的设计

针对传统运动控制器稳定性差、控制效率低、软件构架不完善等特点,结合异构多核技术的优势,提出并开发一种异构多核处理器运动控制器。文章详细阐明该系统硬件设计和软件设计,硬件设计主要说明以异构多核处理器OMAPL138为核心,FPGA为扩展的系统构架;软件设计借助于不同指令集操作系统,利用Sys Link完成多系统平台通信。结合运动控制器的特性,提出异构多核任务调度策略。分析异构多核通信Sys Link的Notify和List MP组件特点,将任务调度策略各条规则,封装到List MP表头,通过查表法实现任务调度策略。通过实验表明,该运动控制器具有较好的实时性和稳定性。

漓江流域δD和δ^18O对蒸发的指示作用

以漓江流域为例查明不同水体之间氢氧稳定同位素组成特征,并探讨氢氧稳定同位素对漓江流域的蒸发过程指示作用.结果表明:流域内不同水体之间,氢氧稳定同位素表现出不同的组成特征,地表水和地下水,在丰水期δD值和δ^18O值要比枯水期更容易富集,地下水的δD值和δ18O值分布范围较地表水小;随着水温的升高,δ18O的变化趋势比d-excess明显.从漓江上游到下游高程逐渐下降,河水线的斜率和截距也在逐渐减小,其中漓江下游河水线的斜率和截距要低于当地大气降水线,表明下游受到蒸发作用较强烈;地下河水线、地表河水线在一定程度上偏离当地大气降水线,但偏离程度较小,表明三者之间有很好的水力联系.受温度和湿度的共同影响,漓江干流丰水期河水的蒸发量占最初水体总量的0.7%~9.1%,枯水期河水的蒸发量占最初水体总量的2.6%~9.7%,丰水期的蒸发比例低于枯水期,从上游到下游蒸发比例在逐渐上升.研究区蒸发量估算值为959.40mm,与多年实测值少43.11mm,相对误差4.70%.氢氧稳定同位素对研究区降水、地表水、地下水之间的转换规律具有重要的实际意义,在今后的漓江流域水文研究中有着更加广阔的空间.

The features of soil erosion and soil leakage in karst peak-cluster areas of Southwest China

Through utilizing water flow monitoring, rock scratching, soil wood piles and radionuclide ^(137)Cs tracing in the Longhe karst ecological experimental site(hereinafter referred to"Longhe site"), Pingguo County, Guangxi Province, the features and values of soil erosion and soil leakage in different geomorphologic locations and land uses in the karst peak-cluster depressions are showed clearly. There are four kinds of geomorphologic locations in the karst peak-cluster depression, namely peaks, strip, slopes and depression. The soil leakage modulus in the peaks and strips respectively occupy 92.43% and 96.24% of the total mean soil erosion modulus at experimental sites. On the slope, soil leakage accounted for about 75%. At the bottom of depression, surface water was the main factor of soil erosion, and at last most soil leaked into underground rivers from sinkholes. The total soil erosion modulus and the contribution rates of relative surface soil erosion in regard of peaks, slopes and depressions gradually increased. There are also five major types of land use in the karst peak-cluster depressions, farmland, Kudingcha tea plantations, young Lignum Sappan fields, shrub-grassland and pastures. The soil erosion modulus of slope farmland has the highest value with an increasing trend year by year. But soil erosion modulus of other four land use types decreased by year, which shows the "grain for green" will result in better soil protection. By handling with rocky desertification and ecological rehabilitation in Longhe site, the mean soil erosion modulus of the karst peak-cluster depression has decreased about 80% from 2003 to 2015.

Seasonal and spatial distribution of trace metals in alpine soils of Eastern Tibetan Plateau,China

The distribution of trace metals in remote alpine region is an effective way to understand the impacts of regional human activity and vegetation on the alpine ecosystem. In this study, the concentrations of cadmium(Cd), copper(Cu), lead(Pb), and zinc(Zn) in the soils of Gongga Mountain, Eastern Tibetan Plateau, were investigated to reveal their seasonal and spatial distribution and enrichment state, and to decipher the effects of atmospheric deposition and vegetation on their distributions among five vegetation zones. The results showed that the concentrations of Cd, Pb, and Zn were higher in the O horizon than in other horizons despite the seasonal changes, whereas Cu was enriched in the C horizon. The enrichment states of the metals studied in the soils decreased in the order of Cd > Pb > Zn > Cu. Cd and Pb were mainly sourced from atmospheric deposition; Zn was from both atmospheric deposition and parent materials, whereas Cu was mainly from parent materials.Seasonally, the trace metals were generally higher in May and December but lower in September, implying the impact of vegetation on the distribution of trace metals under the plant uptake and the litter decomposition. Spatially, the higher enrichment of Cu, Pb, and Zn in the soils existed in the mixed broadleafconiferous forests and coniferous forests(approximately 3000 m above sea level). The results suggested that atmospheric deposition and biological processes are main factors controlling the seasonal and spatial distribution of trace metals in the soils of the remote alpine ecosystem.

典型岩溶矿区地表水和地下水补给来源及水化学演化机制

为研究香花岭矿区岩溶地下水与地表水补给来源、水化学特征及演化过程,在矿区周边采集了32组岩溶地下水与地表水样品,基于多元统计分析、Piper三线图、Gibbs图和离子比例系数等方法,分析了香花岭矿区岩溶地下水与地表水水文地球化学特征,系统揭示了两者的补给来源、补给年代及水化学演化规律.结果表明,香花岭矿区岩溶地下水与地表水呈弱碱性,主要阴阳离子为HCO_(3)^(−)和Ca^(2+),水化学类型以HCO_(3)-Ca型、HCO_(3)-Ca·Mg型和HCO_(3)·SO_(4)^(-)Ca·Mg型为主.大气降水是岩溶地下水与地表水的主要补给来源,在径流过程中一定程度上受到了蒸发作用的影响,但岩溶地下水所受蒸发作用影响相对较小,与现代水水力联系较为密切,循环更替过程更加迅速.岩溶地下水与地表水的水化学演化特征主要受岩石风化作用、阳离子交替吸附作用、矿物溶解作用及人类活动(农业活动、矿业活动)的共同影响,Ca^(2+)、Mg^(2+)和HCO_(3)^(−)主要源于碳酸盐岩矿物的溶解,少部分源于硅酸盐岩矿物的风化溶解,Na^(+)与Cl^(−)主要源于岩盐的溶解,其中Cl^(−)、NO_(3)^(−)和SO_(4)^(2−)受到农业活动、生活污水排放与矿业活动的外源输入的影响较大.研究结果对香花岭矿区岩溶地下水与地表水循环演化过程、水资源保护利用有重要意义.

Inhibition of neovascularization and expression shift of pro-/anti-angiogenic vascular endothelial growth factor isoforms after intravitreal bevacizumab injection in oxygen-induced- retinopathy mouse model

Background Retinopathy of prematurity （ROP） has become one of the leading causes of visual loss in children. Vascular endothelial growth factor A （VEGF-A） is the principal stimulator of angiogenesis. VEGF was differentially spliced from exon 8 to exons 8a and 8b to form two families： the pro-angiogenic VEGFxxx family and the anti-angiogenic VEGFxxxb family. Previous research has shown variable effeteness of bevacizumab in inhibiting retinal neovascularization in ROP. This study aimed to investigate whether the effectiveness of this inhibition depends on the relative ratio of the two VEGF isoforms. Methods Intravitreal bevacizumab injection （IVB） was performed in the oxygen-induced-retinopathy （OIR） mice on postnatal day 12 （P12） （intravitreal phosphate buffered saline （PBS） injection as control）. The Evans blue perfused retina were used to test the retinal neovascularization-leakage （NVL） area and non-perfusion （NP） area. Results The retinal NVL and NP area in the IVB group were significantly smaller than the intravitreal PBS injection group （IVP group）. On P17, the protein level of total VEGF isoforms was significantly inhibited compared to IVP group （P 〈0.05） while VEGFls5b isoform was slight reduced （P 〉0.05）. The switch from pro-angiogenic isoforms to anti-angiogenic isoforms after IVB could be found. The relative protein expression of VEGF165b isoform was significantly higher in IVB group than in IVP group （P 〈0.05） on P17 which was correlated with the reduced ischemia-induced angiogenesis in OIR mice after IVB. Conclusions The anti-angiogenic effectiveness might depend on the relative high expression of VEGF165b after intravitreal bevacizumab injection. Anti-angiogenic therapy is a more effective therapy for ROP.