Use of pyrolysis/GC–MS combined with thermal analysis to monitor C and N changes in soil organic matter from a Mediterranean fire affected forest

In Mediterranean ecosystems, forest fires are a common phenomenon. They involve the transformation of vegetation and litter, leaving charred residues and so influencing the carbon cycle by changing (a) the amounts of soil organic matter and (b) the proportions within it of pools with differing stability. In addition to affecting C cycles, fires also affect the amounts of N within soil organic matter, and its availability.     

Speciation of Selected Minor and Major Elements in Oil Ash I. Operationally Defined Chemical Associations and Aqueous Speciation

This study is focused on the speciation of selected elements in oil ash. Our efforts were directed primarily to obtain information on the various forms of vanadium, chromium and nickel. One sample was characterized via its total composition and via its capacity for releasing various elements. The latter was estimated by hot water and nitric acid extractios. A rapid cold water extraction technique has been developed and utilized for sample preparation prior to aqueous speciation by high pressure ion chromatography (HPIC). Results of the HPIC measurements, in agreement with electron spin resonance (ESR) investigations performed on the solid sample, indicate that 38% of the vanadium is present as VOSO₄, 58% of the chromium is Cr₂(SO₄)₃ and 30% of the nickel is NiSO₄. The pH and the redox potential values of the cold water extract support the existence of these forms. Results of a generic study with successive fractionation extractions show the probable existence of oxides, associations with organic matter and aluminosilicate minerals.     

The preliminary study on juvenile-mature correlation ofPinus koraiensis

Through studying seven analytic trees from two stands ofPinus koraiensis artificial forests, the results show that the individual variation coefficient of tree heigh, dbh and volume decreases with age increasing after age of 25. Age of 25 is the age that difference of individual growth is from acute difference to comparatively stability. The optimum selection age is 25a forPinus koraiensis’s artificial forests according to the analysis of juvenile-mature correlation, and early selection efficiency. (Responsible Editor: Zhu Hong)     

Comparative study of two methods for extraction of aflatoxin from peanut meal and peanut butter

The difference between the CB and Best Foods methods in extracting aflatoxins from peanut products has been studied. The CB method yields 60, 121, 35, and 22% higher results for aflatoxins B1, B2, G1, and G2, respectively for 4 samples of peanut meal and 6 samples of peanut butter studied. Both reverse phase liquid chromatography and thin layer chromatography were used to quantitate the extracted aflatoxins.     

Mild Drought Stress‐Induced Changes in Yield,Physiological Processes and Chemical Composition in Festuca,Lolium and Festulolium

The impact of mild drought stress (3 weeks at 40 % field water capacity) on yield, physiological processes, accumulation of proline and phenolic compounds and forage quality parameters in forage grasses was evaluated in pot experiments. During four different growing periods, the effects of water deficit were assessed in nine varieties from five species (Lolium perenne, Lolium multiflorum, Festuca pratensis, Festuca arundinacea and Festulolium braunii). All measured parameters were affected by drought stress in the different cuts. Photosynthesis, transpiration rate, stomatal conductance and dry matter yield were significantly lower in drought stress than under well‐watered conditions in all varieties. Higher water‐use efficiency was only observed during the first and fourth drought period, while this was not the case in the second and third. Mild drought stress significantly increased the content of proline, phenolic acid, flavonoids, water‐soluble carbohydrates and protein. All tested grasses showed also an increase of organic matter digestibility and cell wall digestibility under drought stress conditions.     

安徽省淮北平原夏玉米主要生育时期旱涝指标与影响评估

为给淮北平原夏玉米高产稳产和防灾减灾以及保险理赔等工作提供参考依据。利用1961—2010年安徽省淮北平原夏玉米生育期间降水资料,采用积分回归分析方法确定了逐旬降水量对夏玉米的增产或减产效应及其影响的关键时段,同时采取降水概率≤20%与≥80%分位数法设计了夏玉米不同生育时段及其全生育期间旱与涝的气候指标,统计分析了夏玉米旱与涝灾的区域分布和灾损率及其风险分布特征。结果表明：淮北平原夏玉米生育期间逐旬降水量的负效应多于正效应,抽雄—乳熟期间降水对夏玉米产量影响显著,期间发生旱或涝灾的减产率分别为12.6%和16.3%。淮北平原夏玉米播种—出苗、苗期—拔节、拔节—抽雄、抽雄—成熟和全生育期旱灾与涝灾的气候指标分别是各自时段内的降水总量≤17.0、≤50.0、≤95.0、≤110.0、≤370.0 mm和≥95.0、≥235.0、≥265.0、≥280.0、≥740.0 mm。淮北平原夏玉米生育期间涝灾多于旱灾,且旱灾与涝灾风险分别呈经向和纬向分布,全生育期旱灾与涝灾的气象相对减产率分别为-22.4%和-28.9%,其他生育时段旱与涝灾的气象相对减产率在-8%~-16%之间。     

Establishment and analysis of dynamic mathematical model for coal gasifier

Based on the analysis of flowing combustion, gasification reaction, and lumped parameter, a three region model is established to predict the temperature and gas components of Texaco coal gasifier. Using mass balance and energy balance equations to each zone, the model takes account of gas solid two phase flow, coal pyrolysis, radiation heat transfer, and heterogeneous and homogeneous kinetic chemical reactions. Based on the model, a program is developed for dynamic and static simulation. After parameterization and simulation analysis, some important trends and conclusions are attained. Because the model can accurately predict the temperature and gas components in jet region, it has widespread engineering application value.     

Design of compatible processing and analyzing system for nuclear signals

To on line detect, store and process nuclear signals with multiple forms and multiple frequencies, a compatible processing and analyzing system for nuclear signals based on ultrahigh speed data acquisition card was constructed. When the source signal is at pulse form, the system records signal with the mode of time digital converting. When source signal is at continuous form, the system records signal with the mode of analog digital converting. The processing procedures and algorithms were designed for various signal forms. The results for nuclear random process such as correlation function and power spectrum were effectively obtained.