Arsenic uptake and transport of Pteris vittata L. as influenced by phosphate and inorganic arsenic species under sand cu｜ture

In order to understand the similarity or difference of inorganic As species uptake and transport related to phosphorus in As-hyperaccumulator, uptake and transport of arsenate (As(Ⅴ)) and arsenite (As(Ⅲ)) were studied using Pteris vittata L. under sand culture. Higher concentrations of phosphate were found to inhibit accumulation of arsenate and arsenite in the fronds of P. vittata. The reduction in As accumulation was greater in old fronds than in young fronds, and relatively weak in root and rhizome. Moderate increases, from 0.05 to 0.3 mmol/L, in phosphate reduced uptake of As(Ⅲ) more than As(Ⅴ), while the reverse was observed at high concentrations of phosphate (≥ 1.0 mmol/L). Phosphate apparently reduced As transport and the proportion of As accumulated in fronds of P. vittata when As was supplied as As(Ⅴ). It may in part be due to competition between phosphorus and As(Ⅴ) during transport. In contrast, phosphate had a much smaller effect on As transport when the As was supplied as As(Ⅲ). Therefore, the results from present experiments indicates that a higher concentration of phosphate suppressed As accumulation and transport in P. vittata, especially in the fronds, when exposure to As(Ⅴ); but the suppression of phosphate to As transport in the root or rhizome may be insignificant when P. vittata when exposure to As(Ⅲ) under sand culture conditions. The finding will help to understand the interaction of P and As during their uptake process in P. vittata.     

Study on the effect of explosion suppression equipment on hydrogen explosions

Hydrogen safety is a critical component of modern industrial safety production. In this study, a set of hydrogen explosion suppression equipment is designed independently. The suppression effects of the equipment on hydrogen explosions are studied at normal room temperature and pressure. The experimental results show that the actuation time of the equipment and the spraying mode of the suppressant are the main factors leading to the failure of the hydrogen explosion suppression equipment. The flame, with a hydrogen equivalence ratio of 0.7 and 1.0, spreads out of control when the suppressant touches the flame front. At this time, the addition of the suppressant enhances flame propagation and increases pressure. In addition, because the suppressant does not fully cover the developing flame, the hydrogen flame with the equivalence ratio of 0.5 eventually breaks through the suppressant cloud, and the explosion happens. However, when the initial flame is completely covered by the suppressant, the hydrogen explosion is suppressed by hydrogen explosion suppression equipment. This research provides a solid and reliable foundation for hydrogen explosion suppression equipment in industrial safety and production protection.     

微波处理沥青烟气的探讨研究

采用响应曲面分析法,对微波处理沥青尾气时,管式炉加热温度、沥青烟预热温度及流量对处理沥青烟的影响进行了分析。结果表明:微波高温加热处理沥青烟气的方法,大大提高了焚烧法处理沥青尾气的效率,并且具有成本降低、设备简单、易于操作、易于控制、系统阻力较小、污染小等特点,这一工艺的提出,也为沥青烟气的处理方法开拓了新的道路。     

一种改进的模拟水灭火过程对抗式交互模型

针对虚拟火灾和燃气真火模拟训练系统中的灭火过程交互模型,研究了改进型对抗式系统动力学特性模型,并完成符号求解。讨论并提出了消防员行为、火场外部特征等要素变化条件下的模型架构,给出了连续时间区间的模拟灭火交互模型序列构成形式。分析了交互过程控制参数特性、功能和物理意义,对灭火过程的简化模拟方法进行了完整描述。运用模型编制了消防水灭火典型过程的参数化交互控制时序规律,给出了灭火过程交互模型实际应用的基本方法和步骤。     

壳聚糖季铵盐的制备及其降尘性能研究

以壳聚糖为原料,对其季铵化改性制备了一种新型煤矿用环保降尘剂。主要包括单体3-氯-2-羟丙基三甲基氯化铵(CTA)的合成与壳聚糖季铵盐（HTCC）的制备。通过单因素试验研究了反应时间、反应温度、碱用量、单体配比等因素对HTCC降尘率的影响,并采用正交实验确定了最佳的工艺合成条件为:m(NaOH)/m(CTA)=1.2,m(CTA)/m(CTS)=3.5,60 ℃下反应10 h;用IR、XRD表征了HTCC。当HTCC投加量为0.4 g/L,pH=6、温度25 ℃时,煤尘去除率达到最大约为94.6%,在降尘领域中有着良好的应用前景。     

七氟丙烷对狭长受限空间油气爆炸抑制实验研究

为研究七氟丙烷对油气爆炸的抑制作用,研制了主动式油气爆炸抑制装置,搭建 了狭长受限空间油气爆炸抑制实验系统,进行了油气爆炸抑制实验,并与无抑爆介质条 件进行了对比,分析了爆炸超压值、火焰传播速度和火焰强度等特性参数变化情况。实 验结果表明:当以3、4和5 kg七氟丙烷作为抑爆介质时,最大超压值分别下降34.05%、 50.78%和55.87%,平均火焰传播速度分别下降72.15%、79.87%和89.23%,火焰持续时间 明显缩短,火焰强度减弱;随着七氟丙烷质量的增加,抑爆效果越显著。     

网状铝合金抑爆材料抑爆性能研究

为评价网状铝合金材料的阻隔防爆性能,基于多孔材料的阻隔防爆机理,采用抑爆材料抑爆性能测试装置和可燃气体爆炸箱及高速摄像机,研究材料在不同填充密度、不同留空率下对液化石油气的燃爆压力的影响,及液化石油气火焰在填充材料的爆炸箱中的传播过程。试验结果表明:填充密度为35 kg/m3、留空率为5%时,材料抑爆性能最好;当抑爆材料在容器内的填充密度一定时,其燃爆压力随留空率增加而增加;与未填充材料相比,填充材料后火焰衰减;此外,得到填充密度、留空率和燃爆压力间的数学拟合公式。降低留空率、增加填充密度能够更好地提高阻隔防爆性能。     

大空间建筑不同排烟系统作用下的烟气控制效果研究

利用FDS(Fire Dynamics Simulator)分别对自然排烟和机械排烟作用下的中庭火灾烟气控制效果进行了数值模拟研究,自然排烟口的面积分别为中庭地面面积的5.6%、11.3%和22.5%,机械排烟量分别为43182m3/h和102000m3/h,同时改变机械排烟口的位置。通过对比各工况下的竖向温度分布、中庭内温度场、烟气层界面高度来判断不同工况下的排烟效果,并计算得到了相应排烟效率来判断各排烟模式下的排烟有效性。结果显示,中庭内的温度和排烟效率都随排烟量的增大而减小,自然排烟的排烟效率最低,仅为17.9%~21.3%,机械排烟量43182m3/h时的排烟效率最高,可达45%左右。     

Identification of cadmium-induced genes in maize seedlings by suppression subtractive hybridization

A maize variety, Huatian-1, had an unusually low translocation rate of cadmium (Cd) (59.6 mg·kg^-1 in the roots and 0.093 mg·kg^-1 in the grain) compared to 24 other varieties while being grown in soils with 16.50 mg·kg^-1 Cd. This indicates that this particular species may have special mechanisms that affect the absorption and translocation pattern of Cd. In this paper, the technique of suppression subtractive hybridization (SSH) was used to isolate and identify Cd-induced genes from Huatian-1 hydroponically ?exposed? to? 0.1 mM ?CdCl₂ ?for? 1 h,? 12 h, 24 h, and 48 h. We found a total of 15 differentially expressed genes in the four groups; 2, 3, 4, and 6 genes were from the groups of 1 h, 12 h, 24 h, and 48 h treatment, respectively. Phospholipase PLDb1 mRNA, adenosine triphosphate (ATP) phosphoribosyl transferase 2, and Sp17 were turned on in the maize in response to Cd stress, and it might provide new clues to explain the mechanism of maize tolerance to Cd.     

彩虹粉引燃危险性实验研究

为了研究彩虹粉引燃危险性,应用固体燃烧速率试验仪初步甄别了彩虹粉传播燃烧能力,发现堆垛状彩虹粉固体火焰传播危险性较低;采用粉尘爆炸筛选装置,判定彩虹粉具有爆炸性;应用最小点火能测定装置测定彩虹粉粉尘云的最小点火能在24~60 mJ之间,最优爆炸浓度为1 167 g/m3;应用快速筛选量热仪测试,彩虹粉在227℃开始分解;固体自燃点测试仪显示彩虹粉在250℃附近会发生自燃。向彩虹粉内添加不同比例相近粒径分布的食用盐粉体进行抑爆研究,结果证明食用盐对彩虹粉具有明显的抑爆效果。