The process of attack identification of data-driven complex oil and gas production systems is often mixed with fault data, which leads to the failure of timely attack defense or fault relief, resulting in the occurrence of attacks and oil and gas production accidents. Most of the current attack detection focuses on the detection of external attacks, ignoring the impact of the possible fault data of the oil and gas system itself on the attack detection. To distinguish abnormal events such as system faults from information attacks in complex oil and gas production systems and improve the accuracy of information physical attack detection in complex oil and gas production systems, an SVM-based undirected graph joint detection method is proposed. Firstly, the key sensors in the complex system of oil and gas production are topologized to form an undirected graph. Secondly, SVM is used to detect the anomalies of the undirected graph sensor system. Finally, the receiving station low-pressure pump system is taken as an example to verify. The results show that the accuracy rate, precision rate, recall rate, and F1 of the proposed attack detection method are above 99
The determination of the critical sliding surface is a crucial aspect of slope stability analysis. In reality, the environment in which slopes are located is often very complex, and the sliding surfaces have different shapes. Therefore, a three-dimensional stability study is proposed, using irregular ellipsoidal shapes as the sliding surface. By constructing the equation of the irregular ellipsoid and applying spatial geometric transformations, an irregular ellipsoid controlled by six parameters, (semi-axis length (a), width (b), height (c), rotation angle (θ), and spatial displacements (tx and tz)), is obtained. The interpolation method is employed to apply the irregular ellipsoid to 3D slopes, thereby generating irregular ellipsoidal sliding surfaces. The slope stability coefficient is calculated by using the residual thrust method and genetic algorithm to determine the critical sliding surface. A comparative stability analysis is conducted between the standard ellipsoidal sliding surface and the irregular ellipsoidal sliding surface through a classic case study. The results show that the Type II irregular ellipsoidal sliding surface aligns well with the mining area. Finally, the research findings are applied to the 3D slope stability analysis of the Shengli West No.2 Open-Pit Coal Mine in China, validating the feasibility of the proposed method.
Auto-ignition temperature (AIT) is one of the crucial exponents in the design of fire and explosion safety measures. Therefore, in this study, quantitative structure-property relationship approach was used to predict the AIT of ternary hybrid liquids based on molecular structure information. The optimal molecular descriptors were calculated and filtered using Mordred software. Twelve mixing rules were proposed for calculating molecular descriptors of mixtures. A prediction model for the AIT value of binary liquid mixtures was developed, validated and evaluated using a back propagation neural network (BPNN) and a one-dimensional convolutional neural network (1DCNN). The relative contribution and positive and negative correlations between individual molecular descriptors and AIT in the model were interpreted using the shapley additive explanations method. The results show that BPNN and 1DCNN models using mixing rule 1 have the best fitting ability, stability and prediction ability. The determination coefficient of the BPNN and 1DCNN models in the training set were 0.996 and 0.992, the root mean square errors were 3.613 °C and 5.284 °C, the mean absolute errors were 2.483 °C and 4.144 °C, the nash efficiency coefficient was 0.996 and 0.992, respectively, the willmott index was 0.999 and 0.998. and the values of the top three molecular descriptors of relative contribution, SssCH2, SsOH and SsCH3, were negatively correlated with the AIT values. The BPNN and 1DCNN models provide an accurate and reliable method for predicting ternary mixing liquid AIT.
The occurrence of safety incidents for existing glass curtain walls (EGCWs) pronounced menace to the security of both lives and property. Undertaking safety assessment for EGCWs carries essential practical significance. However, current fuzzy evaluation methods overlook the uncertainty of indicator weights and the intricacies of rank attribution. In response, this paper proposes a novel approach to the safety assessment of EGCWs. This research establishes a framework of evaluation indicators for EGCWs and divides the safety ranks of each indicator into four tiers: Safe, Mild risk, Moderate risk, and High risk. Quantitative and qualitative indicators are quantified via the variable fuzzy cloud algorithm and cloud model. The information cloud combination weighting method is introduced to determine the weight clouds of indicators. Finally, a two-dimensional assessment result is derived using an improved fuzzy comprehensive evaluation method and fuzzy entropy. The exemplified outcomes demonstrate that this approach captures the safety status of evaluation subjects based on risk ranks, and fuzzy entropy addresses two issues: inconsistent level attribution and the comparison of identical risk ranks. The appraisal method further unveils the safety details of EGCWs, with findings that align consistently with the actual situation.
It is of great significance to study the influence of obstacles on the sound field distribution in the comprehensive mining face system and the noise accumulation law in the roadway, which is of great significance to the prevention and control of mine noise and to improving the occupational health protection level of miners. Based on the multi-physical field coupling analysis software COMSOL Multiphysics, the finite element method and ray acoustic method were used to establish the sound field simulation model of the comprehensive mining face system, which was combined with the field test of the measured weighted sound pressure level of the roadway noise for comparison, and the distribution characteristics of the sound field under the influence of different obstacle obstruction rates, obstacle shapes, quantities, spacings, etc. were further analyzed. The results show that: the simulated values of the sound field in the low and high frequency ranges are basically in agreement with the experimental values, which proves the validity of the simulation model; the overall level of the sound pressure level in the roadway is less affected by the shape, spacing, and number of obstacles, which can be disregarded for the simplification of the roadway model; the obstacle obstruction rate and the attenuation amount of the sound pressure level are positively correlated, and the attenuation amount is within 3 dB if the obstacle obstruction rate is less than 50%; When the obstruction rate is less than 50%, the sound pressure level attenuation is within 3 dB.
The ability of membranes to separate oil vapour is affected by their permeance and selectivity. This study modifies polyether block amide (PEBA) composite membranes with a microporous zeolite, Silicalite-1, or a mesoporous zeolite, MCM-41. The results show that when PEBA composite membranes are modified with these zeolites, the selective layer of the composite membrane is coated more thinly, resulting in a higher flux of organic gas. Silicalite-1 increases the hydrophobicity of the membrane, which facilitates the adsorption of organic vapour on the membrane surface, thus improving the membrane selectivity. In the separation of oil vapour, both modified membranes can effectively increase the gas permeabilities and selectivities. The main mechanism governing gas transport in the MCM-41-modified membrane is Knudsen diffusion, so the selectivity for small molecules is improved more significantly. By contrast, the dissolution-diffusion mechanism is dominant in the Silicalite-1-modified membranes, which considerably increases the selectivity for large molecules.
为了合理地优化元宝山露天煤矿内排土场填方体与英金河改选河道位置的安全距离,开展露天煤矿内排土场的沉降变形规律研究.采用定常伯格斯(Burgers)蠕变模型对排土场填方体细粒土质砂蠕变参数进行反演,应用有限差分软件FLAC3D对内排土场排水垫层砂砾石土蠕变参数进行反演,同时利用FLAC3D对内排土场填土过程进行数值模拟.结果表明:在整个排土过程中,排土场的沉降位移随着时间的延长而增加,在前0～2 a内,沉降位移增加速率较快,在2～4 a内,其增加速率出现减小,而在4 a以后趋于稳定;在细粒土质砂参数反演过程中,在蠕变过程的衰减蠕变阶段,数值计算与现场监测结果差距较大,而在稳态蠕变阶段,数值计算和现场监测值相一致;填土高度对排土场填方体的沉降量及其达到稳定的时间具有影响,填土高度越大,工后沉降量越大,所需达到稳定的时间越长;填方体推进位置对排土场的沉降位移具有较大的影响,合理地优化填方体与河道安全距离可以缩短排土时间.
The construction of a university emergency communication system organization network is very important for fire evacuation of high-rise university dormitory buildings. This paper aims to study the mechanism and law of emergency communication based on organizational communication in case of fire in high-rise university dormitory buildings, and fully consider the risk differences of various scenarios and periods in university dormitory buildings, to evaluate the fire evacuation period risk. Firstly, considering the fire occurrence probability, scenario probability, fire consequence severity, and periodic risk difference, a fire evacuation period risk assessment model for a high-rise university dormitory building is proposed. Then, by analyzing the structure and mechanism of the organizational network of the university emergency communication system, an emergency communication system model based on organizational communication is proposed. Coupling two models, taking a high-rise university dormitory building in Beijing as an example, this paper studies the optimization of an emergency communication scheme based on organizational communication, and evaluates the fire evacuation period risk in various periods with multiple scenarios. By analyzing the emergency communication system model based on organizational communication, it is found that the risk of system mode 1 in scenario 1 and scheme A0 is 4.3% lower than that of system mode 2. Three emergency communication optimization methods are also proposed, and 21 optimization schemes are formed. The optimization effects of efficiency B and efficiency C relative to efficiency A are 4.47% and 19.09%, respectively. And the existing system should choose optimization scheme A4. By evaluating the risk of high-rise university dormitory buildings in each year, month, week, date, hour and other periods, 21 relatively high-risk periods are determined. It is found that reducing the number of system links, improving the transmission efficiency of each link, selecting the appropriate notification sequence, strengthening the safety management of high-risk periods such as late break time, and reducing personnel density can effectively reduce the risk of the fire evacuation.
轻稀土氧化物La2O3和CeO2具有特殊催化性能,可用作生物促进剂.通过提升厌氧膨胀颗粒污泥床(EGSB)反应器的容积负荷,研究La2O3和CeO2对 EGSB反应器的处理效能、稳定性及对厌氧颗粒污泥理化特性的影响.结果表明,容积负荷为12.73 kg/(m3·d)时,添加La2O3和CeO2 后的反应器相较于对照反应器,平均化学需氧量(COD)去除率分别提高7％和11％,对照反应器(R Ⅰ)、添加La2O3反应器(RⅡ)、添加CeO2反应器(RⅢ)的COD平均去除率分别为86％、93％和97％.添加La2O3和CeO2降低了进水COD质量浓度对EGSB反应器出水pH值变化的灵敏度,增强了运行稳定性.经过126 d运行,RI的pH灵敏度比上升33％,而RⅡ和RⅢ分别下降了 69％和67％,添加La2O3和CeO2可降低反应器pH灵敏度比,维持反应器稳定性.添加La2O3和CeO2后,EGSB反应器内厌氧颗粒污泥的沉降速率升高,接种污泥、R Ⅰ、RⅡ和RⅢ的平均沉降速率分别为31.32 m/h、54.96 m/h、72.69 m/h 和 95.12 m/h,RⅢ和 RⅡ 较 R Ⅰ的沉降速率分别提高了 73％和32％.通过电镜观察厌氧颗粒污泥表面微观结构发现,La2O3和CeO2促进了胞外多聚物(EPS)分泌,可强化微生物细胞之间的黏附,进而增加了颗粒污泥的密度和粒径,增强厌氧颗粒污泥的沉降性能.
针对城市燃气管道风险评价时存在各因素相互作用会影响评价结果的问题,通过分析以往燃气事故发生原因、行业专家意见和相关规范标准,筛选整理出4项一级指标和19项二级指标,建立城市燃气管道风险评价指标体系.为保证城市燃气管道风险评价的准确性,引入灰色理论与决策试验法(Decision Making Trial and Evaluation Laboratory,DEMATEL).首先,基于此方法分析各因素之间的影响关系;然后,得出各指标因素在评价指标体系中的重要程度;最后,对中心度进行归一化处理得到各影响因素的权重,结合模糊综合评价的方法对燃气管道进行风险评价.结果表明:阴极保护失效、管道运行年限、管道保护装置和人为破坏是导致燃气管道失效最重要的4个因素,燃气管道的风险等级为中等;分析结果与实际工程相吻合,证明该方法能够有效评估燃气管道风险.
生物安全治理的任务是保障人民健康和生命安全.生物安全治理涉及传染病预防、食品安全、环境保护等诸多方面,任何一个环节出现问题都可能对人民健康和生命安全造成重大威胁,因此加强生物安全治理,提高预防和控制突发公共卫生事件的能力是现代社会治理的核心任务之一.生物安全治理与经济和社会发展密切相关,在生物技术、医疗健康等领域,生物安全治理水平的提高可以促进科技创新和产业升级,推动经济发展和社会进步.生物安全治理与国家安全和社会稳定密切相关,在生物安全领域,一些重大问题的解决需要政府、企业、科研机构、社会团体等各方面的协同合作,因此加强生物安全治理可以促进政府职能转变,推动社会治理体系和治理能力现代化,增强国家安全和社会稳定.
锂电池在生活中的使用越来越普及,但锂电池热失控造成的损失是不可估量的.使用红外热成像监测锂电池表面高温区域面积的扩散,从电池过充、内部隔膜刺穿和外部短路3个方面获取电池热成像的表面高温区域分布.通过MATLAB对电池升温过程中的热成像进行红外图像处理,使用最大类间方差法分割电池表面的高温区域.最后采用高斯逼近函数拟合高温区域面积的变化,分析出3种锂电池热失控的原因.
校园安全教育课程开发与实践能帮助师生了解各种安全知识,提高他们的安全意识,更好地保护自己和周围的人.学生可以通过校园安全教育课程学习各种自我保护的技巧和方法,提高自我保护能力,避免受到各种伤害.校园安全教育课程的开发与实践可促进校园安全文化的建设,并形成全员参与、全方位覆盖的校园安全管理体系.
为提高Cr(Ⅵ)污染土壤治理后的稳定性,采用化学还原剂联合乙酸钠生物刺激对高质量比Cr(Ⅵ)污染土壤进行治理和稳定化.通过测定Cr(Ⅵ)质量比、Cr形态及含量并结合XRD分析,同时对生物刺激过程中Cr(Ⅵ)污染土壤的细菌多样性变化进行监测,对比多硫化钙(Calcium polysulfide,CPS)、硫酸亚铁(FeSO4)、零价铁3种化学还原剂以及乙酸钠用量对高质量比Cr(Ⅵ)污染土壤的治理能力及稳定化效果.结果表明:质量分数为10％的FeSO4与质量比为7 g/kg的乙酸钠联用,在生物刺激50 d时对高质量比Cr(Ⅵ)的去除及稳定化效果最佳,还原率为93.58％,且能够将毒性较大的生物有效态铬全部转化为其他稳定形态的铬.XRD结果表明,两种方法联用后土壤中Cr主要以Cr(Ⅲ)的形式存在.生物刺激过程中土壤细菌群落物种分布变化明显,生物刺激50 d时,富集的细菌类群最多.
为解决繁忙终端区运行效率低下的问题,提出了一种基于点融合进场程序的终端区运行安全和效率评估方法.首先考虑空域结构、障碍物和下降梯度等限制条件,以成都终端区为研究对象,设计点融合进场程序并对其进行安全性评估.使用SIMMOD软件对传统区域导航(Remote Area Navigation,RNAV)进场程序和点融合系统(Point Merge System,PMS)进场程序进行模拟仿真,对比了两种运行模式下、不同交通流场景下的航班冲突次数和运行时间.结果表明:正常流量情况下,PMS程序较RNAV程序的冲突次数和总运行时间分别减少了 80.92％和6.79％;极限流量情况下,PMS程序较RNAV程序的冲突次数和总运行时间分别减少了 17.31％和1.21％.研究表明,点融合程序对于正常流量情况下终端区运行安全和效率提升效果较好,极限流量情况下效果不明显.
多氯联苯(PCBs)广泛存在于自然环境中,严重危害人类健康和生态环境.因此,对PCBs污染土壤治理技术的研究引起人们广泛关注.微生物降解方法由于具有绿色、经济、可持续、不会破坏土壤肥力等优点,成为当前研究热点.介绍了微生物降解PCBs的途径和机理,归纳了各途径常见的降解菌,并结合国内外近年来微生物法降解土壤中PCBs的研究进展,重点阐述了几种促进微生物降解PCBs的新方法:生物刺激与生物强化、污泥改性生物降解、生物电化学系统、生物复苏促进因子降解、原位相转化乳化和生物还原脱氯耦合.提出了微生物降解土壤中PCBs未来研究方向,以期为土壤治理技术应用及后续研究提供科学依据.
为探究偏压对土洞发育的影响机制,在极限平衡法和合理拱轴线的基础上,推导了砂土地层偏压地形下直筒型塌陷覆盖层临界厚度计算公式.通过开展以坡面倾角为主变量、结合填土高度和含水率变化的单因素试验,来论证公式的合理性以及揭示不同因素对倾斜地表下塌陷覆盖层临界厚度的影响机制.结果表明:偏压地形下砂土地层直筒型塌陷的覆盖层临界厚度与土体性质、坡度等参数有关;随坡度增大,覆盖层临界厚度减小,地表塌陷历时缩短;覆盖层临界厚度随含水率增大而减小;土体性质对砂性土覆盖层临界厚度的影响大于坡度等外部因素的影响.该研究成果可为解决平面应变条件下的砂土地层地形偏压工程问题提供试验依据.
收集整理了 2011-2020年全国较大及以上的煤矿事故,分析了我国煤矿较大及以上事故发生的起数、死亡人数、发生事故类型以及事故发生区域的相关规律,然后利用安全熵模型和安全度来分析统计的典型煤矿重大事故案例.结果表明:1)近10 a以来,我国煤矿安全形势有所好转,较大及其以上事故数量和死亡人数呈现出递减趋势;2)在事故类型方面,煤矿较大及以上事故的主要因素是瓦斯、水、顶板以及火;3)从地域方面来看,我国煤矿事故数量相对集中在云南省、贵州省、四川省、湖南省和北方一些煤炭大省;4)系统在生产过程中各个影响因素的安全度不断下降,熵值不断增加,引起系统混乱,导致煤炭事故发生.同时,从安全度的角度提出了有效的预防和治理措施.
银纳米粒子(AgNPs)会对水生生物产生不利影响,然而这些影响背后的抑制机制仍不清楚.通过测定藻细胞生物量、光合色素、氧化应激水平、细胞膜完整性及胞外聚合物含量等指标,研究了表面修饰不同涂层的AgNPs包括支链聚乙烯亚胺涂层带正电的纳米银(bPEI-AgNPs)和柠檬酸盐涂层带负电的纳米银(Cit-AgNPs)对淡水藻类中的代表性蓝藻铜绿微囊藻(Micracystis aeruginosa)的影响作用机制.数据表明,两种纳米颗粒均对铜绿微囊藻生长起到抑制作用,损害其光合作用,导致大量电子累积从而使藻细胞产生氧化胁迫,细胞分泌大量胞外聚合物来减缓损伤,且抑制程度随着颗粒投加量的增加而增大,特别是带负电荷的Cit-AgNPs对藻细胞的抑制效应更明显,其抑制程度是同质量浓度带正电荷的bPEI-AgNPs的4～5倍.总的来说,该研究结果为不同表面电特性纳米银与铜绿微囊藻的相互作用提供了新的见解,促进了对于纳米银在淡水藻类中的抑制机制的理解,同时有助于后续研究不同表面电性纳米银颗粒在水环境中的迁移转化规律.
煤矿井下综采工作面视频目标跟踪作为井下视频监控的重要一环,在保障井下作业人员安全、构建智慧煤矿等方面发挥着重要作用.煤矿井下场景复杂多变,现有的目标跟踪算法在煤尘、目标形变和矿灯动态光束等场景下难以取得良好的跟踪效果.因此,在ATOM(Accurate Tracking by Overlap Maximization)算法基础上建立双重调制网络和通道注意力机制,可克服复杂环境的影响.双重调制网络由通用交并比(Intersection over Union,IoU)调制和空间调制网络构成.其中,空间调制网络通过记忆查询的方式提取出第一帧与当前帧特征点间的关联程度,以对目标关键特征信息进行增强.通道注意力模块嵌入主干网络,通过建立残差通道注意力机制,学习表示通道重要程度的权重系数,提升主干网络对关键特征信息的提取能力.算法的有效性在工作面视频目标跟踪数据集上得到验证,成功率提升1.48％,精确率提升3.9％,Pnorm得分提升2.75％.改进后的模型效果提升显著,更加适应于煤矿场景下的目标跟踪.
