Estimating soil moisture content using laboratory spectral data

Monitoring soil moisture is important for agriculture and forestry and plays an essential role in land surface processes as well as providing feedback among the earth’s surface ecosystems. Large-scale regional soil moisture spatial data can be obtained with a reliable and operational approach using remote sensing. In this paper, we provide an operational framework for retrieving soil moisture using laboratory spectral data. The inverted Gaussian function was used to fit soil spectral data, and its feature parameters, including absorption depth (AD) and absorption area (AA), were selected as variables for a soil moisture estimate model. There was a significant correlative relationship between soil moisture and AD, as well as AA near 1400 and 1900 nm. A one-variable linear regression model was established to estimate soil moisture. The model was evaluated using the determination coefficients (R2), root mean square error and average precision.Four models were established and evaluated in this study. The determination coefficients of the four models ranged from 0.794 to 0.845. The average accuracy for soil moisture estimates ranged from 90 to 92%. The results prove that it is feasible to estimate soil moisture using remote sensing technology.     

Effects of biochar and litter on carbon and nitrogen mineralization and soil microbial community structure in a China fir plantation

To investigate the effects of biochar addition(1 or 3%)to the soil of a China fir plantation with or without litter,we conducted a 90-day incubation experiment.We also studied the C and N dynamics and the microbial community structure of the soil.In soil without litter,the application of biochar at a rate of 3%significantly decreased CO2 emissions,while addition of 1%biochar had no effect.Biochar application did not affect the net N mineralization rate but significantly reduced the NH4?concentration after 90 days.In litter-enriched soil,biochar application had no significant effect on total CO2 emissions;however,application of 3%biochar significantly reduced the net N mineralization rate.Biochar application to soil with or without litter immediately reduced the dissolved organic carbon(DOC)concentration independent of the application rate,which was primarily due to sorption of DOC by the biochar.Phospholipid fatty acid analysis demonstrated that both concentrations of added biochar to soil(with or without litter)altered the soil microbial community structure at the end of incubation,although the effect of biochar was not as strong as the effect of time or litter application.The effect of biochar addition alone on microbial community structure was inconsistent over time.Litter added to soil significantly increased fungi and reduced Gram-positive bacteria.In the presence of litter,biochar applied at both 1%and 3%significantly increased(p<0.05)the proportion of actinomycete only at day 90.Our results indicate biochar as a potentially effective measure for C sequestration in the test soil of a China fir plantation,even in the presence of litter.     

伞裙追寄蝇滞育期间主要物质含量变化研究

为了明确伞裙追寄蝇滞育过程中主要抗寒物质及其含量的变化,对伞裙追寄蝇滞育期间主要物质总糖、蛋白质和脂类含量的变化进行了研究。结果表明,糖原含量在滞育期高于非滞育期的浓度,具有显著差异,且在蛹期达到最大值,分别为156.73μg/mg、68.32μg/mg,两者差异显著。在伞裙追寄蝇进入滞育之前,非滞育期蛋白质含量较高,在蛹期达到最大值为78.34μg/mg;滞育期则为72.95μg/mg,二者差异显著。滞育和非滞育成虫体内的甘油含量很低,在整个发育过程中,除蛹期外,其他各时期伞裙追寄蝇的甘油浓度在滞育期高于非滞育期,且差异均显著。比较各物质含量可知伞裙追寄蝇滞育时的主要抗寒物质是糖原。     

清代华中地区干旱灾害时间特征及成因分析

基于清代(1644-1911年)华中地区干旱灾害历史资料的搜集与整理,利用启发式分割算法和互补集合经验模态函数等方法,分析华中地区干旱灾害的时间分布特征。结果表明:1)清代华中地区旱灾发生频繁,共208年次,占总年数的77.6%,其变化总体上呈下降趋势。2)华中地区旱灾于1694年发生突变,突变后旱灾频率明显减少。3)华中地区旱灾存在显著的周期性,存在2.6a、9.7a、21.6a、29.4a和102.1a的周期,其中9.7a和21.6a的周期与太阳黑子周期相一致。4)交叉小波分析表明太阳黑子数与华中地区旱灾变化在不同时间段内具有不同程度的相关关系。     

Finite element simulation of duct grouting to standard prestressed concrete beam

For the duct grouting of prestressed beams,due to the narrow passageways grouting,the paste in the flow condition is very complex. In order to understand the grouting body in flow,the article establishes a three dimension finite element model of the grouting body,and uses the fluid mechanics software Fluent to analyze the grouting process of the standard prestressed beams through the finite element numerical method for the first time. The results show in the speed of cloud,the paste which is in a straight space and passes top space flows slow,may cause grouting defects. In the cloud of duct static pressure,the static pressure in the centre of the duct is greater than those on both ends. When paste is in hydration process,secrete water is forced to flow to the two ends,which causes grouting defects. The analysis results provide theoretical and actual testing data processing support for grouting nondestructive testing technology.     

Improve DaLaTe Energy-saving Analysis of Dry Coal Mill 5 Furnace of the Power Output

Coal-fired power plant is an energy energy-intense, coal consumption for the whole year is very huge, improve the utilization efficiency of coal-fired power plant of a device, as far as possible to reduce power generation cost, this article through the ac     

Optimization of hydrolysis conditions for the production of angiotensin-I converting enzyme-inhibitory peptides and isolation of a novel peptide from lizard fish (Saurida elongata) muscle protein hydrolysate

Lizard fish (Saurida elongata) muscle protein was hydrolyzed using neutral protease to produce protein hydrolysate (LFPH), and the hydrolysis conditions were investigated using response-surface methodology. The optimum conditions for producing peptides with the highest angiotensin-I converting enzyme (ACE)-inhibitory activity were the following: enzyme-to-substrate ratio of 10,000 U/g, temperature of 48 °C, pH 7.0, and hydrolysis time of 2 h. Under these conditions, the ACE-inhibitory activity of LFPH and the degree of hydrolysis were 84% and 24%, respectively. A novel ACE-inhibitory peptide was isolated from LFPH using ultrafiltration, Sephadex G-15, and high-performance liquid chromatography. The amino acid sequence of the ACE-inhibitory peptide was identified as Ser-Pro-Arg-Cys-Arg (SPRCR), and its IC₅₀ was 41 ± 1 µM.     

北京市科普惠农兴村计划效果评价

在分析北京市科普惠农兴村计划效果评价现状的基础上,运用层次分析法,建立效果评价指标体系并赋予权重。利用该评价指标体系,分析2013年度北京市科普惠农兴村计划的统计数据,得出北京市各郊区县实施该计划的效果。      

大学生安全教育现状及对策

大学校园安全文化是一种独具特点的文化现象,它以人为本,以文化为载体,通过文化的渗透提高人的安全价值观,规范人的安全行为,它是安全价值观和安全行为准则的总和。分析了大学生安全教育的现状,并提出了发展对策。      

旋转磁场对饲用植酸酶活性影响的试验研究

试验采用来自国内外不同企业生产的4种植酸酶试剂,常规条件下分别在旋转磁场中处理0、5、10、15、20、25min,用钒钼磷显色法检测酶活性,试验结果表明:其中3种酶活性受到旋转磁场影响不显著,而另一种酶活性却降低到原活性的50%左右,其原因可能是由于磁场改变了植酸酶的空间结构,从而影响其活性。