Predictions for isomer distributions of toxic dioxins and furans in selected industrial combustion processes

Three thermodynamic databases of polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) have been used to simulate the PCDD/F isomer distribution in industrial combustion processes. The three databases had been derived using the Group Additivity approach and two computational molecular modelling methods, Modified Neglect of Diatomic Overlap (MNDO) and Parametrized Model 3 (PM3), respectively. The predictions of the toxic PCDD/F isomer distributions using the three different databases have been compared with measured values from industrial processes. An excellent agreement between the predictions using the MNDO method and the measured data has been obtained. It is concluded that the PCDD/F isomer distributions within each group observed in these combustion processes may be thermodynamically controlled.     

三明化工厂开展班组危险预防分析活动几点经验

介绍了班组开展危险预防分析活动的几种方法与经验。     

企、事业单位专职安技员队伍建设探讨

本文对专职安技员及队伍现状进行了分析,根据专职安技员的职业生涯三阶段客观规律,偿试将个人和组织的需要进行合理匹配,探讨提高专职安技员业务素质和安技队伍专业水平的对策.     

Prediction models for the flash point of pure components

The flash point for a liquid is defined as the lowest temperature at which its vapor forms a spontaneously ignitable mixture when brought in contact with air. Having a good estimation of the flash point temperature at normal conditions is relevant because it is one of the main properties used to characterize fire and explosion hazards for liquids. Most of predictive correlations in the literature include a physical effect by including the normal boiling temperature in their formulation. To achieve combustion, sufficient evaporation is required and then a part of the liberated energy from the combustion is used to support the evaporation. Thus the evaporation energy and a chemical effect given by the heat of reaction are incorporated in this work. It is firstly verified that the relation between the flash point temperature and the normal boiling temperature tends to be a constant. Thus a heuristic approach based on 611 chemical species of diverse families indicates that this relation is around 0.75. The dispersion of the error has been reduced by using two proposed correlations where both physical and chemical properties are included in the model. In particular, the second equation is based on the group contributions method, which has been developed for alkanes. This method is in fact a combination of the group contributions method and the first model to overcome the difficulties in predicting isomeric differences.     

荷兰生态（有机）农业对上海农业发展的借鉴

安全高效、资源节约、环境友好型的生态农业生产技术,已成为国际农业领域研究和关注的热点;发展高效生态（有机）农业,以新的强度和效能为长三角和我国现代化农业发展作贡献,是上海社会主义新农村建设的重大战略,是上海现代农业发展的必由之路。荷兰生态（有机）农业发展提供了以下成功经验：以生态学原理指导农业生产,实现生产生态共荣;在农产品生产中应用HACCP理论,加强农业生产的过程控制和质量管理;通过制定良好农业技术规范（Eurep-GAP）,保障农业的可持续发展,保护生态环境。上海发展高效生态（有机）农业的对策建议：加强政策扶持,深化有机农业理论和技术研究,建立和规范与国际接轨的认证体系,以生态学的原理和原则指导农业生产和技术的发展。     

Costs of switching social groups for dominant and subordinate dark-eyed juncos (Junco hyemalis)

I quantified the costs of switching from a familiar to an unfamiliar flock for captive dark-eyed juncos (Junco h. hyemalis) by measuring several physiological and behavioral variables before and after flock switching. Birds that were initially dominant dropped in status in unfamiliar flocks, and experienced increased metabolic rates, while subordinate birds appeared to undergo less physiological change when switching flocks. This difference occurred despite a lack of any rank-related differences in the effects of joining a new flock on rates of aggression, weight change, access to food, or plasma corticosterone levels. These results suggest that for dominant, but not subordinate, individuals there is a measurable metabolic cost to joining a new social group, even in the absence of adverse factors such as food limitation. Dominant individuals may be less likely than subordinates to leave familiar flocks because of their higher metabolic costs when joining a new social group.     

长株潭城市群PM2.5中二次无机离子特征及生成机制

二次无机离子是大气PM_2.5的主要组分,其对城市霾污染的驱动作用愈发明显.目前长株潭城市群秋冬季PM_2.5污染形势依旧严峻,但该区域的二次转化对冬季霾污染过程以及秋冬季SNA差异特征的影响尚不明晰.2020年11月和2021年1月在长株潭城市群4个典型站点进行PM_2.5连续采样,并定量分析了SO₄^2-、 NO^-₃和NH⁺₄等组分.结果显示,秋季和冬季PM_2.5中ρ(SO₄^2-)、ρ(NO^-₃)、ρ(NH⁺₄)平均值(μg·m^-3)分别为(5.2±2.5)、(7.9±4.8)、(4.1±2.2)和(7.2±4.2)、(17.1±10.5)、(7.8±5.2).在冬季霾污染过程中,ρ(SO₄^...     

关中城市群生态足迹演变趋势及公平性评价

自然资本与人造资本的分配公平与配置效率是可持续共享区域生态资源的保证。论文在测算2005—2014年关中城市群生态足迹的基础上,以生态足迹、生态承载力、GDP分别表征区域内自然资本需求、自然资本收益、人造资本收益,采用基尼系数、时空分析指标、生态承载系数、经济贡献系数分析区域资源分配公平与配置效率的程度。结果显示,2005—2014年,关中城市群生态承载基尼系数、经济贡献基尼系数、综合基尼系数分别置于 [0.18, 0.20]、[0.24, 0.29]、[0.23, 0.28]区间。同时,结果表明,关中城市群GDP上升趋势显著快于生态足迹,生态要素匹配较好,其中,咸阳市、宝鸡市、铜川市属相对“高生态承载贡献、低经济贡献”城市,西安市、杨凌示范区属相对“高经济贡献、低生态承载贡献”城市。     

Swarm cognition in honey bees

We synthesize findings from neuroscience, psychology, and behavioral biology to show that some key features of cognition in the neuron-based brains of vertebrates are also present in the insect-based swarm of honey bees. We present our ideas in the context of the cognitive task of nest-site selection by honey bee swarms. After reviewing the mechanisms of distributed evidence gathering and processing that are the basis of decision making in bee swarms, we point out numerous similarities in the functional organization of vertebrate brains and honey bee swarms. These include the existence of interconnected subunits, parallel processing of information, a spatially distributed memory, layered processing of information, lateral inhibition, and mechanisms of focusing attention on critical stimuli. We also review the performance of simulated swarms in standard psychological tests of decision making: tests of discrimination ability and assessments of distractor effects.     

百脉泉泉群泉水氢氧稳定同位素时空变化特征

研究泉水氢氧稳定同位素时空变化特征,探究泉水的补给来源,对水资源管理及旅游业可持续发展具有重要指导意义。以百脉泉泉群为研究区,通过分析降水及泉水中的氢氧稳定同位素特征,获取了本地大气降水线、泉水同位素时空变化特征及蒸发线,并探究了百脉泉泉水的补给来源。结果表明：大气降水中δ²H的波动范围为-151.55‰δ¹⁸O—-4.28‰,δ¹⁸O的波动范围为-19.93‰δ¹⁸O—-0.52‰,δ²H和δ¹⁸O在时间上的分布规律相似,均呈现双峰状(“M”型),本地大气降水线(LMWL)为：δ²H=7.58×δ¹⁸O+4.17。百脉泉泉水的δ²H的波动范围为-65.23‰δ¹⁸O—-37.01‰,δ¹⁸O的波动范围为-8.99‰δ¹⁸O—-4.04‰。泉水δ²H—δ¹⁸O均落在本地大气降水线上或...