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21.
马建华 《中国环境管理干部学院学报》2005,15(1):38-41
采用顶空气相色谱法测定食品中甜蜜素含量,探讨了气液相平衡条件及色谱条件的选择,实验结果表明甜蜜素的标准溶液在0.1-0.4μg/l范围内具有良好的线性关系,回收率为87.5%-101.8%,相对标准偏差为2.6%. 相似文献
22.
On July 31, 2014, at around 23:57, several huge explosions occurred that lasted for 2 h in Kaohsiung City, Taiwan. As a result of a gas leak from a ruptured underground pipeline, the catastrophic incident destroyed more than 6 km of roads, killed 32 people, injured 321 people, and damaged 3259 buildings. Pipeline explosions have been reported as a repeatedly occurring problem, indicating that (1) complex systems are difficult to manage and control, and (2) humans are unable to effectively learn from experiences of accidents. Initial analyses results reveal that root causes of this incident were a combination of a series of complex chain reactions, which eventually led to propylene leakage and explosion. This is a systematic problem, which can hardly be investigated or analyzed by traditional research approaches. Based on the investigation reports and “systems thinking” method, this study develops causal loop diagrams for the Kaohsiung gas explosion to explore the root causes of the disaster. The research results indicate that (1) this pipeline explosion incident was the result of the chain reactions and was the output of a complex system; (2) the mental model of “production first” and “experience gap” were the root causes of the disaster; and (3) to achieve a higher safety standard, continuous education to improve the mental model of “safety first and safety over production” are essential. The findings of this study may contribute toward the improvement of the standard operating procedure for disaster management and preventing similar incidents in the future. 相似文献
23.
In this study, in order to research the synergistic inhibition effect of nitrogen and ultrafine water mist on gas explosion in a vented duct, a semi-confined transparent chamber was designed with the size of 120 × 120 × 840 mm, and the experiments were carried out with stoichiometric methane/air premixed mixture (fraction of methane: 9.5%), adding different fractions of nitrogen and ultrafine water mist. The experimental results showed the following: The combination of nitrogen and ultrafine water mist had a synergistic inhibiting effect on methane/air explosion, which was preferable to the single use of any kind. With the increase of spraying time of water mist and fraction of nitrogen, the initial shape of the explosion flame became snakelike, and at the same time the peak flame propagation speed and peak overpressure decreased significantly. When the nitrogen fraction was increased to 10% and the mist spraying time was increased to 2min, synergistic inhibiting effect on overpressure was high efficient. However, with the increase of spraying time of water mist and fraction of nitrogen going on, the amount of increase of explosion inhibition efficiency was gradually reduced. 相似文献
24.
To study the mechanism of the suppressing effect of Expanded Aluminium (EA) on the premixed gas explosion, premixed methane-air and propane-air gases were undergone explosion reaction in the presence of EA in a self-designed closed pipeline with the overpressures and the compositions, rates and sensitivities of products analyzed. The results showed that the 9.5% methane-air and 5% propane-air explosions produced peak pressures decreased by 79.3% and 65.6%, and residual methane and propane contents increased by 270% and 560% respectively than without EA. In addition, the results revealed that the explosions of propane in the presence of EA produced less methane and carbon oxides contents, but more ethylene and propylene contents. The simulation showed that H, O, and OH are the key factors affecting the rate of products. The product compositions, together with other parameters, suggested that EA decreased temperature, inhibited chain initiation and propagation reaction, but facilitated chain termination reaction by advancing and accelerating the gas phase and wall destruction reaction of radicals, especially collisions and concentration of key free radicals. This new research method based on the analysis of explosion products can be used for in-depth research into gas explosion features and shed light on the suppressing mechanism of EA in flammable gas explosion. 相似文献
25.
Jiangsu Wen Changchang M Pengwei Huo Xinlin Liu Maobin Wei Yang Liu Xin Yao Zhongfei M Yongsheng Yan 《环境科学学报(英文版)》2017,29(10):98-107
Visible-light-driven photocatalysis as a green technology has attracted a lot of attention due to its potential applications in environmental remediation. Vesicle Cd Se nano-semiconductor photocatalyst are successfully prepared by a gas template method and characterized by a variety of methods. The vesicle Cd Se nano-semiconductors display enhanced photocatalytic performance for the degradation of tetracycline hydrochloride, the photodegradation rate of78.824% was achieved by vesicle Cd Se, which exhibited an increase of 31.779% compared to granular Cd Se. Such an exceptional photocatalytic capability can be attributed to the unique structure of the vesicle Cd Se nano-semiconductor with enhanced light absorption ability and excellent carrier transport capability. Meanwhile, the large surface area of the vesicle Cd Se nano-semiconductor can increase the contact probability between catalyst and target and provide more surface-active centers. The photocatalytic mechanisms are analyzed by active species quenching. It indicates that h+and UO_2~-are the main active species which play a major role in catalyzing environmental toxic pollutants. Simultaneously, the vesicle Cd Se nano-semiconductor had high efficiency and stability. 相似文献
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针对某居住区附近氯气储罐连续泄漏,通过求解三维不可压缩Navier-Stokes方程、K-ε湍流模型和物质浓度方程,模拟毒气在建筑物扰动条件下的扩散过程以及浓度时空分布特征,以毒气负载为基础给出近地面毒气危害区域,探讨毒气扩散对周边居民的影响。 相似文献
28.
采用气袋直接进样法测定环境和污染源空气中的丙烯腈。结果表明:丙烯腈在0.4~99.5 mg/m3浓度范围内具有良好的线性关系,相关系数为0.999 8。在低、中、高3个添加水平回收率为88.9%~100%,相对标准偏差为0.6%~4.7%,均能较好地满足实验室分析要求。 相似文献
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30.
本文将低浓度瓦斯与脉动燃烧结合,主要研究了脉动频率对低浓度瓦斯燃烧的影响。实验结果发现:频率为99Hz至120Hz之间的脉动燃烧不仅可以降低贫燃极限.实现瓦斯在5%浓度下稳定而充分的燃烧,而且在相同温度下提高了瓦斯燃烧效率,污染物的排放也得到了改善。 相似文献