生物炭早期植物毒性评估培养方法研究

为更加科学地评估生物炭潜在植物毒性,采用生物炭(B)、生物炭+土壤(B+S)、生物炭水浸提液+土壤(AE+S)、生物炭+石英砂(B+Q)、生物炭水浸提液+石英砂(AE+Q)5种不同的培养方法进行早期植物毒性效应实验。比较分析不同培养方法中西红柿种子发芽率、根长、芽长对生物炭的响应。结果表明:在5种培养方法中,随生物炭剂量增加,西红柿种子发芽率、根长、芽长呈现先增后降的变化趋势。虽在低剂量生物炭处理下(10.0 g·kg~(-1)),种子萌发表现出促进作用。但随剂量增加,除B+S和AE+S外,均表现出一定的抑制作用,且当剂量为160.0 g·kg~(-1)时,抑制作用达到最大。对比有土和无土培养方法中种子萌发情况发现,在高剂量下,无土培养方法中种子发芽率,根、芽生长所受抑制作用显著高于有土培养方法。无土方法中,尤其AE+Q方法中,高剂量生物炭对种子发芽率、根长、芽长表现出最大的抑制作用,其中发芽率抑制率为91.1%,根长抑制率为77.7%,芽长抑制率为93.7%。综合比较分析,生物炭水浸提液+石英砂(AE+Q)的培养方法干扰因子少,可提高毒性响应灵敏度。因此,在生物炭早期植物毒性效应评估中,该法可作为推荐的培养方法。     

Cr(Ⅵ)对脊尾白虾(Exopalaemon carinicauda)幼虾暴露和恢复期肝胰脏的SOD活性、MDA及MTs含量的影响

为了探索水体中Cr(Ⅵ)对脊尾白虾(Exopalaemon carinicauda)的毒性效应,通过Cr(Ⅵ)的暴露(15 d)和清水恢复实验(15d),研究了Cr(Ⅵ)对脊尾白虾肝胰脏的SOD活性、MDA及MTs含量的影响.结果表明,通过15 d的暴露,5 mg·L-1(高浓度)、0.5 mg· L-1(低浓度)实验组肝胰脏的SOD均显著高于对照组水平(p＜0.05),15 d的清水恢复后,两个浓度实验组均能够恢复到对照组水平(p＞0.05).MDA在暴露阶段呈现持续上升的趋势,且在15 d后两个浓度实验组MDA的含量均显著高于对照组水平(p＜0.05),15 d的清水恢复后,5mg·L-1实验组的MDA含量依然显著高于对照组水平(p＜0.05),0.5mg·L-1实验组的MDA含量基本恢复到对照组水平(p＞0.05).通过15 d的暴露,两个浓度实验组MTs的含量均显著高于对照组水平(p＜0.05),15 d的清水恢复后,两个浓度实验组MTs的含量均能够恢复到对照组水平(p＞0.05).     

Low blood lead levels and hemoglobin concentrations in preschool children in China

It is well known that lead (Pb) produces reduced haemoglobin (Hb) levels and risk of anemia when blood lead levels (BPb) are greater than 20?µg?dL^?1. Two recent studies reported an increased risk of anemia in children with BPb between 10–20?µg?dL^?1, but few studies examined the association between Hb levels or risk of anemia and BPb under 10?µg?dL^?1. In the present study this association was examined using data of 140 preschool children from a larger prospective cohort study in China. Data showed that compared to children with BPb <5?µg?dL^?1, children with BPb between 7.5–10?µg?dL^?1 had significantly lower Hb levels, but there were no marked differences for other groups. A linear regression model showed a negative relationship between BPb and Hb levels after controlling for age, gender, height, weight, and iron (Fe) deficiency. This finding, although limited by a small sample size, suggests it may be important to examine Pb-induced hemosynthesis effect at concentrations less than 10?µg?dL^?1.     

Dissipation of polycyclic aromatic hydrocarbons and microbial activity in a field soil planted with perennial ryegrass

Dissipation and plant uptake of polycyclic aromatic hydrocarbons (PAHs) in contaminated agricultural soil planted with perennial ryegrass were investigated in a field experiment. After two seasons of grass cultivation the mean concentration of 12 PAHs in soil decreased by 23.4% compared with the initial soil. The 3-, 4-, 5-, and 6-ring PAHs were dissipated by 30.9%, 25.5%, 21.2%, and 16.3% from the soil, respectively. Ryegrass shoots accumulated about 280 μg·kg^-1, shoot dry matter biomass reached 2.48 × 10⁴ kg·ha^-1, and plant uptake accounted for about 0.99% of the decrease in PAHs in the soil. Significantly higher soil enzyme activities and microbial community functional diversity were observed in planted soil than that in the unplanted control. The results suggest that planting ryegrass may promote the dissipation of PAHs in long-term contaminated agricultural soil, and plant-promoted microbial degradation may be a main mechanism of phytoremediation.     

助剂强化罐底油泥的压滤脱水性能

采用实验室压滤装置对胜利油田某联合站罐底清罐油泥进行压滤脱水研究,采用单独添加助滤剂G、絮凝剂PAM或PAC均可改善过滤效果,提高滤速,降低过滤比阻。但仅使用助滤剂G时滤速的提高尚不够理想,单独使用絮凝剂PAM或PAC时,滤饼含水率偏高,滤饼不易从滤布上剥离;絮凝剂PAM 0.1%与助滤剂G 3.0%复配,滤饼比阻由空白样的18.7×1012 m/kg降低到0.05×1012 m/kg,3 min即可使滤饼含水率降到74.16%,滤液澄清,滤饼成形性好,较仅添加絮凝剂PAM时,更容易从滤布上剥离。     

Effects of particle characteristics on flame propagation behavior during organic dust explosions in a half-closed chamber

To reveal the effects of particle characteristics on the mechanisms of flame propagation during organic dust explosions clearly, three long chain monobasic alcohols which are solids at room temperature and have similar physical–chemical properties were chosen to carry out experiments in a half-closed small chamber. A high-speed video camera was used to record the flame propagation process and to obtain the direct light emission photographs. Flame temperature was detected by a fine thermocouple. Based on the experimental results above, analysis was conducted on flame propagation characteristics and temperature profiles of organic particle cloud. As a result, it was found that the particle materials, especially volatility, strongly affected the flame propagation behavior. Particle concentration also affects the combustion zone propagation process significantly. With increasing the particle concentration, the maximum temperature of the combustion zone increases at the lower concentration, reaches a maximum value, and then decreases at the higher concentration. The propagation velocity of the combustion zone has a linear relationship with the maximum temperature, which implies conductive heat transfer is dominant in the flame propagation process of the three different volatile dusts.     

Preparation and characterization of surface modified powder of calcium hydroxide used as chlorine scavenger

In order to avoid existing shortcomings of chlorine leakage treatment, we developed a new chlorine scavenger. The main composition of the chlorine scavenger was calcium hydroxide. The chlorine scavenger was prepared by wet process with water as solvent through adding surface active agent and silicone oil, etc. The influence of surfactant on modified powder was investigated, which included the sodium dodecyl benzene sulfonate, the sodium stearate, the water-soluble silicone oil, the emulsifying silicon oil and the amino silicone oil, and the effect of modification of judgment were illustrated, which mainly involved the sifting rate, the bulk density, the contact angle, on this basis, also the author analyzed the powder of modification by using SEM analysis and size distribution, The modified powder had the following characteristics: high absorptivity, anti-caking, good air permeability and so on. The results showed that overall performance of modified powder was better than the performance of unmodified powder. The adding amount of sodium stearate was preferably 2% while the optimum amount of emulsifying silicon oil and amino silicone oil was 3%. The comprehensive performance of powder modified with compound modifiers was better than the performance of the powder modified with a single modifier. The property of powder modified with sodium stearate and amino silicone oil had a good performance analyzed from the uniformity of particle size distribution of the powder and anti-caking. The powder modified with sodium stearate and emulsifying silicon oil had a good absorption rate of chlorine.     

放电降解苯酚的能量计算及火花放电的控制

实验观察了脉冲电晕放电等离子体降解水中有机污染物苯酚过程中的电压波形图及参数,并对其进行了分析研究,讨论了降解过程中的能量计算问题,分析了放电过程中产生火花放电的原因,并提出了控制火花放电的方法。在其它放电参数相同的情况下。比较了有无泄放电路对苯酚降解率的影响。     

模糊综合评价在建筑机械管理中的应用

应用模糊综合评价方法对建筑机械管理进行定量的综合评判,以期能够定量地预警。     

高压脉冲等离子体降解水中苯酚的实验研究

对高压脉冲放电等离子体技术降解水中有机污染物苯酚进行了实验研究,观察了脉冲成形电容、脉冲峰值电压、脉冲频率、放电电极直径、放电距离、苯酚的人口质量浓度等因素对苯酚降解率的影响;实验结果表明脉冲成形电容有一最佳值;降解率随脉冲峰值电压、脉冲频率增大而升高,随放电电极直径和放电距离的减小而增大,随苯酚人口质量浓度增大而增大。