重型柴油车实测排放因子和MOBILE6预测值的对比分析

利用车载尾气检测技术(PEMS)可以获得实时的机动车排放数据.笔者利用PEMS实测了重型柴油车的排放数据,在此基础上分析了CO、HC、NOx和PM的排放因子与速度、加速度的关系,同时使用MOBILE6模型,经过模型参数的校正,从而得到相应的预测排放因子,最终对排放因子的实测值、MOBILE6模型预测值以及欧Ⅱ的排放标准估测值进行了对比分析.     

基于静态特征和动态行为的火灾检测模型

为实时准确地检测视频监控的火灾信号,减少火灾误报,提出1种基于静态特征和动态行为的火灾检测方法.利用改进的Faster RCNN检测模型,根据可疑火灾区域的颜色特征和空间特征对其进行目标检测和特征降维,与传统的Faster RCNN相比平均检测精度提升5％;利用ILSTM对连续帧中的特征进行累加,对短期内是否发生过火灾...     

北京地区PM10与秸秆燃烧排放单颗粒对比分析

采用场发射带能谱扫描电镜(FESEM/EDS)法分析北京怀柔地区PM10与秸秆燃烧排放颗粒的形貌特征和成分差异.结果显示:秸秆燃烧后排放颗粒物多为大粒径颗粒,成分上都含S、Cl和K元素.含有生物质燃烧标志元素K的PM10颗粒物多为含Si、Al和Na元素的燃煤飞灰和矿物颗粒,与秸秆燃烧排放颗粒组成化学元素差异明显.据此推...     

Modeling the carbon dynamics of the La Grande hydroelectric complex in northern Quebec

A mechanistic semi-empirical carbon cycle model of the La Grande reservoir complex in northern Quebec, Canada was conceived in order to investigate the climate impact of such a large alteration of the continental water cycle. The model includes inputs from the drainage basin, organic matter release from flooded soils, CO₂ emissions across the water-atmosphere interface and sedimentation. Most input data stems from previous research by our group on those ecosystems. The model includes the seven reservoirs of the La Grande complex and was run for periods of 50 and 100 years. Terrigeneous dissolved, particulate and suspended soil carbon fluxes and concentrations were computed. Over 100 years, 31.3 × 10¹² g C are released from flooded soils, equivalent to 28-29% of inputs from the drainage basin. 40-74% of dissolved organic carbon is mineralized. CO₂ fluxes over 100 years are 50.5-79.8 × 10¹² g C, 46.4-67.9 × 10¹² g C more than in the absence of reservoirs. The increase in mineralization of organic matter and in CO₂ emissions is a result of the increase in cumulated water residence time due to the creation of the reservoirs. Changes in other carbon sinks and sources likely offset a part of this additional carbon flux to the atmosphere. In the first years following flooding of the reservoir, organic carbon release from flooded soils exceeds CO₂ emissions, implying the downstream export of large quantities of eroded soil organic carbon. After this initial period, CO₂ emissions are fuelled by organic carbon originating from the drainage basin.     

交通事故动态分析法在肇事逃逸案件侦查中的研究与实践

针对传统交通事故动态分析法在交通肇事逃逸案件侦查中投入高、效率低、精度差的缺点,笔者在信息主导警务理念的指导下,综合运用逻辑学、系统科学、社会学、心理学、情报科学相关原理,动态分析交通事故现场的痕迹、车辆行驶轨迹、道路交通环境、警情综合信息、驾驶人行为与逃逸心理,以及受害者损伤特征,准确掌握车辆或驾驶人局部特征,从而为侦破交通肇事逃逸案件提供精确的查缉信息,使警务行动实现精确用警、快速反应和精确打击的目标。笔者给出了利用动态分析法侦破交通肇事逃逸案件的流程和步骤;指出提高办案水平,迫切需要加强警务信息和社会信息的有效融合,研发专门系统,强化信息研判。     

采场通风方式与瓦斯运移规律研究

采场是煤矿生产的核心地带,而采场通风系统是确保采场作业安全,创造良好生产环境的重要环节。本文以采场风流流动及瓦斯运移理论为基础,通过现场试验、模型模拟试验及计算机模拟研究等方法,着重研究了中国常用的和有发展前途的走向长壁后退式U型通风方式、U+L型通曲方式、后退式Y型通风方式条件下采场风流流动及瓦斯运移规律。     

COMPARISON OF RESERVOIR LINEAR OPERATION RULES USING LINEAR AND DYNAMIC PROGRAMMING1

ABSTRACT: Mathematical optimization techniques are used to study the operation and design of a single, multi-purpose reservoir system. Optimal monthly release policies are derived for Hoover Reservoir, located in Central Ohio, using chance-constrained linear programming and dynamic programming-regression methodologies. Important characteristics of the former approach are derived, discussed, and graphically illustrated using Hoover Reservoir as a case example. Simulation procedures are used to examine and compare the overall performance of the optimal monthly reservoir release policies derived under the two approaches. Results indicate that, for the mean detention time and the corresponding safe yield target water supply release under existing design of Hoover Reservoir, the dynamic programming policies produce lower average annual losses (as defined by a two-sided quadratic loss function) while achieving at least as high reliability levels when compared to policies derived under the chance-constrained linear programming method. In making this comparison, the reservoir release policies, although not identical, are assumed to be linear. This restricted form of the release policy is necessary to make the chance-constrained programming method mathematically tractable.     

AAS与ICP－AES间接测定天然水中硫酸盐

本文以与过量形成ＢａＳＯ＿４沉淀反应为基础，较详细地讨论了反应条件、从而拟定了用ＡＡＳ和ＩＣＰ－ＡＥＳ间接测定天然水中的方法、确定了方法的精密度，ＡＡＳ法的ＲＳＤ％为１．５，ＩＣＰ－ＡＥＳ法为３．２．两种方法对比分析的结果接近，误差为１．０％（相对）。用于天然水中的测定，获得满意的结果。