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。     

模具中雷管爆炸的冲击波防护距离研究

为了研究模具中雷管爆炸产生的冲击波超压对雷管生产线传输皮带周围操作人员的伤害范围,测量了模具中单发到50发雷管同时爆炸后不同距离的空气冲击波超压峰值,并拟合了超压衰减曲线;根据空气冲击波超压与人员伤害程度的最小压力关系,得到了避免传输皮带周围操作人员出现"轻微"、"中等"、"严重"、"极严重"伤害时的安全防护距离。利用空气冲击波峰值超压公式定量分析了模具对其中雷管爆炸产生冲击波的吸收,表明模具具有良好的冲击波吸收作用。     

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。     

障碍物对瓦斯爆炸冲击波影响研究

为研究障碍物对瓦斯爆炸冲击波传播规律的影响,利用水平管道式气体——粉尘爆炸实验装置,测试并分析障碍物数量、尺寸和壁面粗糙程度对瓦斯爆炸冲击波超压、冲击波传播规律的影响。结果表明:障碍物对瓦斯爆炸过程中冲击波传播规律具有重要影响。障碍物存在时,改变了爆炸冲击波的传播规律,提高了冲击波超压的最大峰值压力,且随着障碍物数量和尺寸的增加,这种激励作用越明显。随着壁面粗糙程度的增大,瓦斯爆炸冲击波超压明显增大。研究结果对井下巷道瓦斯爆炸冲击波的防治具有一定的指导意义。     

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。     

Will climate change overwhelm fire management capacity?

Using anomalies calculated from General Circulation Model (GCM) climate predictions we developed scenarios of future fire weather, fuel moisture and fire occurrence and used these as the inputs to a fire growth and suppression simulation model for the province of Ontario, Canada. The goal of this study was to combine GCM predictions with the fire growth and suppression model to examine potential changes in area burned in Ontario due to climate change, while accounting for the large fire suppression activities of the Ontario Ministry of Natural Resources (OMNR). Results indicate a doubling of area burned in the Intensive and Measured fire management zones of Ontario by the decade of 2040 and an eightfold increase in area burned by the end of the 21st century in the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (IPCC SRES) A2 scenario; smaller increases were found for the A1b and B1 scenarios. These changes are driven by increased fire weather conducive to large fire growth, and increases in the number of fires escaping initial attack: for the Canadian GCM's business-as-usual (A2) scenario, escaped fire frequency increased by 34% by 2040 and 92% by the end of the 21st century. Incorporating more detail on large fire growth than previous studies, our model predicts higher area burned under climate change than do these previous studies, as large numbers of high-intensity fires overwhelm suppression capacity.     

低压配电线路剩余电流断路器动作判据的研究

为了改善剩余电流断路器频繁误动作的问题,提出以偶次谐波变化率最小值阈值、工频变化量阈值、剩余电流动作整定值相结合的三重判据.首先,搭建活体触电试验平台,获取活体不同部位的多组触电试验数据,利用S变换提取触电波形谐波特征,并计算出触电时刻偶次谐波变比率最小值阈值和工频变化量阈值.其次,搭建人体触电仿真模型,发现存在相似的...     

电弧焊防触电技术探讨

从电焊机保护接地（或接零）的规则、电源线与焊钳的安全技术、控制电器的安全技术、电焊工作业中的安全保障措施等四个方面,探讨了电弧焊作业中如何防范触电事故的技术措施,实践证明,所述的安全要求和技术方法对于电弧焊作业的安全管理和安全生产具有很高的实用价值。     

覆盖法控制城市河涌底泥磷释放研究

建立了一套包含有城市河涌底泥、覆盖材料及上覆水的小试装置,采用粉煤灰、水泥、沸石、河砂、玻璃珠等不同物质作为覆盖材料,在厌氧条件下,覆盖材料对城市河涌底泥磷释放的控制效果进行了研究.结果表明,在培养温度为25℃,覆盖材料用量为6.0kg·m-2时,玻璃珠、河砂、沸石、粉煤灰、水泥对PO43-释放的抑制率分别为40.0%、46.7%、60.0%、75.6%、88 9%;覆盖材料对PO43-的抑制作用可归结为覆盖材料的覆盖效应、化学效应和吸附效应;覆盖材料对PO43-释放的抑制率均随着温度的升高而降低;覆盖材料用量对PO43-抑制率影响较大,对于水泥、粉煤灰、沸石、河砂,要达到约50%的PO43-释放抑制率,其用量分别为2.0、2.0、6.0、10.0 kg·m-2,选用粉煤灰作为覆盖材料较合适;从重金属毒理学方面讲,覆盖材料不会对底泥及区域土壤造成影响.