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关键词： 流体包裹体   氢氧同位素   钼矿床   华北地台北缘中段   张家口   朱家洼  

摘要： 张家口朱家洼钼矿床是近年来华北地台北缘中段继内蒙古曹四夭特大型钼矿床之后发现的又一个规模可达大型的钼矿床。钼矿床主要呈半隐伏-隐伏状围绕分布于骆驼山岩体周边。本次对矿区2个钻孔中采集的11件富含辉钼矿的石英矿物,进行了包裹体岩相学、显微测温、包裹体气、液相成分及氢氧分析。结果显示:该矿床流体包裹体可分为4种类型:富液相包裹体、富气相包裹体、含子晶包裹体和富CO2三相包裹体。其中,富CO2三相包裹体分布较少,其余3种类型包裹体常见。含子矿物的包裹体均一温度、盐度分别在400℃和45%NaCl eqv左右;富液相包裹体均一温度平均值为277.43℃,盐度20%NaCl eqv左右;富气包裹体和富CO2包裹体均一温度分别为380℃和30℃;盐度较低,分别为6%NaCl eqv和2.04%NaCl eqv左右。气液相成分分析显示流体体系成分以H2O、Cl^-、F^-、Na^+、K^+离子为主,Ca^2+,SO4^2-含量较低,特征离子比值暗示流体来源于岩浆流体。成矿流体总体上属于H2O-NaCl体系。氢氧同位素组成显示,成矿流体主要来源于岩浆水。沸腾作用是辉钼矿沉淀的主要机制。

关键词： 混合溶液   表面张力系数   泡泡半径   气体参数  

摘要： 本文测量了将食盐和白糖加入市售泡泡液中配成的不同浓度液体的表面张力系数,及其液体吹出来的泡泡半径,并由其比值计算获得泡泡液内外压强差的数值约为0.318Pa或0.029Pa,即肥皂泡内外压强差是一个很小的值域,0.1~0.01Pa.理论分析泡泡内外压强差,理想气体模型数值为21.669kPa,范德瓦耳斯气体模型数值为0.0133Pa,在实验数值的范围内.可以认为在张掖这个海拨高度,用范德瓦耳斯气体模型来处理实际气体,是合理和可行的.

关键词： 多态系统   成功流法   共有信号   通用发生函数   可靠性  

摘要： 针对成功流(GO)法可靠性分析过程复杂问题,将通用发生函数(UGF)与GO法结合,提出适用于复杂系统可靠性分析的UGF-GO算法。该算法通过分析GO图中各操作符结构关系,建立相应的系统结构UGF计算公式分析系统可靠性,不仅降低了GO图的计算复杂度,而且还简化了GO图共有信号修正过程。通过对比概率公式算法与UGF-GO算法的可靠性分析结果,验证了UGF-GO算法应用于复杂多态系统可靠性分析的有效性与简便性。UGF-GO算法应用于某型飞机供电系统,结果表明从失效机理到退化建模,UGF-GO算法能完整地分析具有性能退化行为的系统可靠性。

关键词： 减量增效   农药喷洒   雾滴飘移   数值模拟   药液性质   喷施优化   黏度   表面张力  

摘要： 研究农药雾滴的空间运行规律及其影响因素,对减少飘移、保护环境及助剂开发都有重要意义。选取2%甲氨基阿维菌素苯甲酸盐(简称甲维盐)乳油,采用Euler-Lagrange离散相模型对雾滴空间运行过程进行数值模拟,分析了农药雾滴的空间运行轨迹。结果表明:黏度和表面张力对雾滴空间运行规律的影响主要作用于喷头出口处的雾化过程,雾化过程的结果决定了后续雾滴空间运行的轨迹和飘移率。药液黏度和表面张力越大,出口处大粒径雾滴所占的比例越高,雾滴的平均粒径和空间运行速率相应增大,在空间运行过程中停留时间缩短,飘移率降低。确定了标准条件下黏度和表面张力调控的适宜范围:黏度在0.001~0.01 Pa·s之间,飘移率为18.77%~12.67%;表面张力在0.042~0.060 N/m之间,飘移率为38.93%~24.40%。针对实际场景,提出了调控药液物理性质的具体方案:通过将2%甲维盐乳油的黏度和表面张力分别增大至0.01 Pa·s和0.060 N/m,可以分别将4 m/s和5 m/s风速条件下的飘移率降低18%和43%,从而有效降低了农药雾滴的飘移损失。

关键词： 蒸汽流量计   差压式流量计   皮托管  

摘要： 该文分析了影响蒸汽流量准确计量的主要因素,介绍了传统的蒸汽流量计如孔板流量计和涡街流量计的使用局限性,详细介绍了一种基于皮托管原理的新式差压式流量计的设计原理、结构特点及其标定方法,通过实例给出了典型蒸汽工况下选择流量计的考虑因素,以及应用这种新式差压式流量计的选型和计算过程。

关键词： 华庆地区   核磁共振   微观孔喉结构   可动流体   主控因素  

摘要： 致密砂岩储层的微观孔喉结构特征复杂,流体的赋存特征和渗流特征差异性明显,是目前致密砂岩储层开发的关键问题所在。本文以鄂尔多斯盆地华庆地区长63致密砂岩储层为例,采用核磁共振、恒速压汞、高压压汞、扫描电镜、铸体薄片等多种微观实验方法相结合对比分析,对储层可动流体进行定量评价,并探讨影响储层可动流体变化差异性成因的主控因素。研究结果表明致密砂岩储层T2谱形态分布复杂,主要表现为双峰结构形态,且左右峰幅度高低不等,同时具有一定的多峰和单峰形态。微观孔喉结构特征的非均质性是导致可动流体赋存特征差异的主要控制因素,同时黏土矿物的成分、含量、分布形式以及充填孔喉程度也是影响可动流体赋存特征的重要因素。

关键词： Truck flow   Estimation   Data fusion   Nonlinear optimization  

摘要： Knowledge of spatial distributions of weight-categorized truck flows in a region is critical to the understanding of movements of empty or partially-loaded trucks and devising appropriate strategies to reduce empty or partially-loaded truck flows and improve truck utilization efficiency in the region. However, such disaggregated information cannot be directly obtained from existing data sources and models. In this paper, we propose a compact model for estimating weight-categorized truck origin-destination (OD) flows and link-level truck counts by fusing several freight datasets. The proposed model minimizes the squared errors between the estimated and observed truck OD flows and link volumes considering the flow conservation of trucks and commodity weights. To illustrate a real-world application of this model, a case study is conducted to estimate the spatial distribution of empty or partially-loaded truck flows into, within, and out of the State of Florida. With the case study results, high production- and attraction-zones of empty or partially-loaded truck trips are also identified. Such results can potentially inform freight planning and policy decisions to learn spatial patterns of empty or partially-loaded backhauling truck flows and devise countermeasures to reduce such flows and improve freight transportation efficiency. This is particularly relevant to a terminal state such as Florida that has large volumes of back-hauling truck flow.

关键词： Shoe manufacturing waste   Combustion   Circulating fluidized bed   Gas emissions   PCDD   PCDF  

摘要： Shoe manufacturing waste (SMW) was combusted in a 2.5 MWth pilot-scale circulating fluidized bed combustor (CFBC) to demonstrate the feasibility of energy recovery and provide useful information for a fluidized bed combustor design specifically for this waste. The experimental results confirmed that the stable combustion could be achieved in this CFBC with a constant feed flow rate of 400 kg/h, a primary air flow rate of about 1650 Nm(3)/h and a second air flow rate of about 1800 Nm(3)/h. The pollutants in the flue gas (ITFG) were measured with the average values of CO2 at 9.9%, CO at 2145.04 ppm, NOx at 81.67 ppm, SO2 at 32.62 ppm, HCl at 3.12 ppm, HF at 0.57 ppm, Pb at 0.0029 mg/m(3), Cd < 0.001 mg/m(3), Hg at 20.938 ng/Nm(3), and PCDD/ PCDF at 1.17E(-03) ng TEQ/m(3), respectively. CO and SO2 emissions exceeded the legal limits in China, while the combustion efficiency was relatively low. Therefore, in order to meet the CO emission limit, some useful suggestions were put forward for the future CFBC design to burn SMW. A flue gas desulfurization system is essential to reduce the SO2 emission. Very low Cu content, high level of residual carbon in the fly ash and high SO2 concentration ITFG resulted in low PCDD/PCDF emission.

关键词： PM2.5   dust collectors   morphology characteristic   element composition   industrial fluidized bed boilers  

摘要： This study presented new field measurement data on the particle size distributions, morphological characteristics, and elemental composition of particulate matter (PM)(2.5) (particle diameter less than 2.5 mm) from 12 industrial boilers, including eight circulating fluidized bed boilers (CFB) and four bubbling fluidized bed boilers (BFB). Measurement in situ was taken with an electrical low-pressure impactor equipped with a two-stage dilution sampling system. Morphological characteristics were determinded by electron microscope (SEM), and elemental compositions of the samples were determinded by X-ray fluorescence (XRF) and inductively coupled plasma (ICP). The results show that before and after the dust removal, the number concentration distributions of PM2.5 display bimodal distributions, one peak is between 0.07 and 0.12 mu m, and the other peak is between 0.32 and 0.48 mu m. And the particle concentrations of PM2.5 depended mainly on submicron particles (less than 1 mu m in diameter), formed by gasification-condensation mechanisms. The mass concentration distributions of PM2.5 showing no peak distribution and increase with the particle size. Compared to electrostatic precipitators (ESPs) and fabric filters (FFs) , the ESPs has a lower removal efficiency of PM2.5. The morphological characteristics of PM2.5 before and after dust removal contain irregular particles and spherical particles. The mass percentages of Na, K, and Fe in PM2.5 after the dust removal are nearly the same as those before the dust removal, but Si, Ca, and Al in PM2.5 decreased after dust removal and S in PM2.5 increased after dust removal. Although the hazardous elements Cr, V, Mn, and Ni in PM2.5 after dust removal did not change significantly, the Pb, Cd, As, Se, and Hg increased after dust removal. These data clearly show that the composition of PM2.5 changes as dust are removed by air pollution control devices.

关键词： Software-defined networking   SDN   DDoS   New-flow   OpenFlow   SDN security   DDoS detection and, mitigation  

摘要： Software-defined Networking (SDN) is an emerging technology that revolves around the fundamental notion of setting up a network with a decoupled control plane and data plane. It brings numerous benefits such as improved network manageability, flexibility, and programmability to measure up to the enormous demands of future networking. However, it also comes with security concerns that are intrinsically present in SDN's architecture. In classic SDN, a switch acts as a forwarding device that has to forward a packet towards the centralized controller for every new flow that comes into the network. Out of this design philosophy, a new-flow based distributed denial-of-service (DDoS) attack is born, which presents this internal flow-based policy as a critical security vulnerability to confiscate the scarce resources of the control plane and data plane in an SDN network. In this paper, we propose a classification of such security vulnerabilities exposed by SDN architecture and leveraged by a new-flow based DDoS attack. We also provide an analysis of the latest developments made in recent years on DDoS detection and mitigation research works to overcome these security vulnerabilities. Finally, we discuss SDN security-related research challenges that can be valuable for the research community and academics for carrying out further research and investigation.