基于微分动态逻辑的数字化反应堆控制系统建模与验证方法

核电数字化仪系统既涉及反应堆随时间变化的物理动态演化过程,又涉及计算机的离散控制过程,属于典型的实时混成系统。微分动态逻辑是近年在混成系统验证领域的新方法。提出以微分动态逻辑为基础的构建反应堆控制系统安全验证模型方法,验证反应堆控制系统中离散化的逻辑控制与反应堆连续性的物理连续变化过程之间的相互作用能否保证反应堆安全需求,从而提高数字化反应堆控制系统设计的安全性。     

列车运行控制系统安全保障与认证方法研究

为了保证轨道交通系统的运行安全性,系统必须在其投入运行之前进行安全认证,只有取得相应的安全授权才能投入运行。结合CENELEC国际标准和我国应用实践,提出以安全验证和确认为基础的安全保障与认证方法,将安全验证和确认的方法贯穿于系统研制开发生命周期内的每一个阶段,监控系统研制开发的每一个活动,评审系统研制开发的每一个文档,保证相关文档之间的追溯性,针对系统的所有需求进行完备性和充分性测试,才能够确保列车运行控制系统能安全、可靠地投入使用。列车运行控制系统是轨道交通系统的重要组成部分,关系其运行安全和效率2,010年底采用安全验证和确认的方法成功地将LCF-300型列车运行控制系统应用于北京轨道交通亦庄线和昌平线,并顺利通过英国劳氏公司的第三方安全认证。     

军工材料环境适应性工程化验证和研究发展战略探讨

通过对国内外发展现状分析,讨论了环境适应性工程化验证和研究在军工材料开发、应用及其在武器装备发展中的地位和作用。提出了军工材料环境适应性工程化验证的技术内涵、试验与研究的模式和军工材料开发到武器装备应用各个阶段的任务和目标。在此基础上。探讨了发展军工关键材料环境适应性工程化验证试验与研究的总体战略和目标。结合国情。提出了军工关键材料环境适应性工程化验证与研究和关键材料体系环境适应性数据完善．军工关键材料环境适应性工程化验证自主保障能力建设．军工关键材料环境适应性工程化验证技术的提升等3方面重点发展和研究内容的构想与建议。     

江苏省化工行业LDAR逸散量占比核定方法研究

以江苏省为例,针对化工企业装置泄漏检测与修复(LDAR)逸散量和挥发性有机物(VOCs)排放总量定量分析,提出了一种核定典型化工行业LDAR逸散量占比的方法。结果表明:以间歇性生产为特点的有机化工类企业和以连续化生产为特点的石化类企业LDAR逸散量和VOCs排放总量均呈下降趋势;石化类企业LDAR逸散量占比呈下降趋势,有机化工类企业LDAR逸散量占比呈上升趋势;石化类企业LDAR逸散量占比远大于有机化工类企业,是无组织排放管控的重点;有机化工类企业LDAR逸散量占比虽然低,但对VOCs排放的贡献逐渐提高。     

复合填料一维冻胀量数值模拟分析

复合填料是以废铸砂、粉煤灰、聚苯乙烯颗粒(EPS)、水泥和水为原料,拌合后形成的一种轻质填筑材料。其中,EPS颗粒含量适当时,能减少或消除复合填料的冻胀和融沉,可作为季节性冻土区的路基填料。假设复合填料中除EPS颗粒外的骨料颗粒、孔隙冰为刚性介质,同时考虑EPS颗粒变形和填料孔隙变形对复合填料冻结过程的影响,在已有的冻土水热耦合分离冰模型的基础上,得到考虑EPS颗粒变形影响的饱和填料一维冻结水热耦合控制方程,进而预测填料的冻胀量。与室内模型试验结果对比表明,本文模型可用于该种具有弹性颗粒复合填料的冻胀量模拟,为工程中冻胀量预测提供依据。     

原子吸收分光光度计的期间核查实例

期间核查是指采用简单实用并具相当可信度的方法,对可能造成质量不合格的测量设备或参考标准、基准、传递标准或者工作标准以及标准物质（参考物质）的某些参数,在两次相邻的定期检定／校准之间的时间间隔内进行检查,以判定设备是否保持着校准或检定时的准确度,以确保检测和校准结果的质量,并及时发现和纠正仪器设备因漂移、老化、破损、样品污染及其他未知原因造成的失准,确保仪器在使用期间一直保持良好的状态,维持检测结果的可信度。笔者在参阅资料和文献的基础上,对本单位的原子吸收分光光度计进行了一次期间核查,结果是各项指标均符合标准。     

Exploring Persistence in Streamflow Forecasting

In this study, the authors explore three persistence approaches in streamflow forecasting motivated by the need for forecasting model skill evaluation. The authors use streamflow observations with 15 min resolution from the year 2008 to 2017 at 140 United States Geological Survey streamflow gauges monitoring the streams and rivers over the State of Iowa. The spatial scale of the basins ranges from about 7 to 37,000 km². The study explores three approaches: simple persistence, gradient persistence, and anomaly persistence. The study shows that persistence forecasts skill has strong dependence on basin scales and weaker but non‐negligible dependence on geometric properties of the river network for a given basin. Among the three approaches explored, anomaly persistence shows highest skill especially for small basins, under about 500 km². The anomaly persistence can serve as a benchmark for model evaluations considering the effect of basin scales and geometric properties of river network of the basin. This study further reiterates that persistence forecasts are hard‐to‐beat methods for larger basin scales at short to medium forecast range.     

Global radioxenon emission inventory based on nuclear power reactor reports

Atmospheric radioactivity is monitored for the verification of the Comprehensive Nuclear-Test-Ban Treaty, with xenon isotopes ^131mXe, ¹³³Xe, ^133mXe and ¹³⁵Xe serving as important indicators of nuclear explosions. The treaty-relevant interpretation of atmospheric concentrations of radioxenon is enhanced by quantifying radioxenon emissions released from civilian facilities. This paper presents the first global radioxenon emission inventory for nuclear power plants, based on North American and European emission reports for the years 1995–2005. Estimations were made for all power plant sites for which emission data were unavailable. According to this inventory, a total of 1.3 PBq of radioxenon isotopes are released by nuclear power plants as continuous or pulsed emissions in a generic year.     

Establishing a measurement,reporting, and verification system for climate finance in post-Paris agreement period

The measurement, reporting, and verification (MRV) of climate finance was originated from discussions under the United Nations Framework Convention on Climate Change (UNFCCC). It has been one of the key issues of global climate negotiations since 2009 and will continue to be of significant importance in addressing climate change and strengthening international trust. This paper analyses the concept, the objective, and the progress of the MRV of climate finance based on reviews of the latest literature and think-tank reports regarding climate finance regime and MRV. Following the analysis, challenges faced with the MRV of climate finance are illustrated. This paper presents that the comparability of climate finance data needs to be improved due to the variety of methodologies used for disaggregating climate finance. In addition, the integrality of the MRV system of climate finance has been impaired by the lack of feedback mechanism from the recipients to the contributors in reporting system. Furthermore, although accounting system of climate finance has been developing and improving, it remains incapacity in providing accurate data on disbursed climate finance. Responding to the above challenges, this paper proposes the key tasks in establishing a comprehensive MRV system for climate finance at international level. The tasks involve developing a measurement system with consistent data basis and accounting basis, a reporting system with more detailed guidance and standardized formats, as well as a verification mechanism balancing top-down and bottom-up review processes. In the last section, this paper concludes that the establishment of an improved MRV of climate finance requires concerted cooperation and negotiations between developed and developing country Parties under the UNFCCC. As one of the few developing country donors to the Global Environmental Facility (GEF), China is suggested to clarify its propositions as a developing country in aspects such as concept, coverage, and architecture of climate finance and MRV system, and gain bargaining power in improving operating and technical rules of international climate finance regime.     

Inter-laboratory comparison study on measuring semi-volatile organic chemicals in standards and air samples

Measurements of semi-volatile organic chemicals (SVOCs) were compared among 21 laboratories from 7 countries through the analysis of standards, a blind sample, an air extract, and an atmospheric dust sample. Measurement accuracy strongly depended on analytes, laboratories, and types of standards and samples. Intra-laboratory precision was generally good with relative standard deviations (RSDs) of triplicate injections <10% and with median differences of duplicate samples between 2.1 and 22%. Inter-laboratory variability, measured by RSDs of all measurements, was in the range of 2.8-58% in analyzing standards, and 6.9-190% in analyzing blind sample and air extract. Inter-laboratory precision was poorer when samples were subject to cleanup processes, or when SVOCs were quantified at low concentrations. In general, inter-laboratory differences up to a factor of 2 can be expected to analyze atmospheric SVOCs. When comparing air measurements from different laboratories, caution should be exercised if the data variability is less than the inter-laboratory differences.