上海设施蔬菜主要品种污染物含量调查评估

通过对上海郊区单栋大棚、连栋大棚和现代化智能温室生产的叶菜类和茄果类设施蔬菜的主要品种污染物（农药和硝酸盐）含量抽样调查，并以附近大田蔬菜作为对照，分析结果发现，上海郊区设施蔬菜农药和硝酸盐的污染物含量普遍高于大地蔬菜，且超标状况比较严重。究其因，设施蔬菜生产较常规大田蔬菜生产农药与化肥使用水平高，而且在封闭环境条件下污染物降解速度慢，容易残留或积累超标。     

祁连山北坡自然恢复杨桦林地植物功能型组成及其影响因素

依据生活型(乔木、藤本、灌木、半灌木、多年生禾草、多年生杂类草和一二年生草本)和水分生态型(旱生、旱中生、中生和湿生)将祁连山北坡次生杨桦林28个调查样地中的81个物种划分为18种植物功能型(Plant functiontypes,PFTs),并通过典范对应分析(CCA)方法研究植物功能型与环境因子间的关系.结果表明:自然恢复杨桦林地植物功能型主要集中在中生多年生杂类草(PFTs16)、湿生多年生杂类草(PFTs23)、旱中生多年生杂类草(PFTs9)和中生灌木(PFTs18)4个植物功能型上;乔、灌、草三层冠层特征和中生植物的大量出现,反映了群落植物生活型趋于复杂化和结构化,生态型逐渐向中生化方向演替的特点;土壤容重、有机碳和全氮含量主要影响植物的生活型分异特征,土壤含水量和林冠郁闭度是植物的水分生态型分异的主要环境因子,而坡位、坡度控制着群落植物总体分布格局的形成.图1表3参31     

过氧化氢及次氯酸钠的同步电合成及其原位氨氮去除效果

利用电解法在离子隔膜电解槽反应器的阴阳极室以较高的电流效率分别合成了过氧化氢和次氯酸钠。对原位合成的次氯酸钠等含氯氧化剂的氨氮去除效果进行了考察,在初始ρ(NH_4~+-N)为1 000 mg/L和电极间距为5 mm的条件下,阴极合成过氧化氢的电流效率和TN去除率均高达100%。     

Associations of long-term ambient air pollution and traffic-related pollution with blood pressure and hypertension defined by the different guidelines worldwide: the CHCN-BTH study

Environmental Science and Pollution Research - The assessment of the generalization of the strict hypertension definition in the 2017 ACC/AHA Hypertension Guideline from environmental condition...     

Historical distribution of lynx (<Emphasis Type="Italic">Lynx lynx</Emphasis>) in Northeast China on the basis of historical records

Long-term dynamics of population decline can improve the conservation perspectives and strategies for endanger species. In China, new gazetteers having systematic compilation and wide geographical coverage can be considered as an important complementary for reconstruction historical distribution. For historical and cultural reasons, an endangered species–lynx (Lynx lynx) was recorded regularly in new gazetteers. Therefore, the aim of this paper was to evaluate the population distribution in Northeast China from the 1950s to 2014. The data show that Felis lynx was widely distributed in Northeast China in the 1950s, but the number of the occurrence records have been significantly reduced by 85.6% in the last 60 years. This research also enlightens us that the new gazetteers can contribute to data shortage and it would be helpful to conservation biology.     

当代大学生勤俭精神缺失的原因及对策

在当今社会,大学生群体对传统文化的摒弃愈发严重,在许多消极社会思潮的影响下,其价值判断标准发生了变化,勤俭精神在不同程度地缺失,这对于大学生的成长成才具有很大的负面影响.本文从需求层次的提升、社会环境的改变以及教育的缺位三个方面探讨了当代大学生勤俭精神缺失的深层次原因,并针对这些原因,提出了改变这种现象的相应对策.     

Transpiration rates of urban trees, Aesculus chinensis

Transpiration patterns of Aesculus chinensis in relation to explanatory variables in the microclimatic, air quality, and biological phenomena categories were measured in Beijing, China using the thermal dissipation method. The highest transpiration rate measured as the sap flux density of the trees took place from 10:00 am to 13:00 pm in the summer and the lowest was found during nighttime in the winter. To sort out co-linearity, principal component analysis and variation and hierarchical partitioning methods were employed in data analyses. The evaporative demand index (EDI) consisting of air temperature, soil temperature, total radiation, vapor pressure deficit, and atmospheric ozone (O₃), explained 68% and 80% of the hourly and daily variations of the tree transpiration, respectively. The independent and joint effects of EDI variables together with a three-variable joint effect exerted the greatest influences on the variance of transpiration rates. The independent effects of leaf area index and atmospheric O₃ and their combined effect exhibited minor yet significant influences on tree transpiration rates.     

The expansion process of a Stellera chamaejasme population in a degraded alpine meadow of Northwest China

Environmental Science and Pollution Research - The expansion of poisonous plants can change vegetation community structures and affect grassland ecosystem service values. Stellera chamaejasme is...     

LPG港口的定量风险分析

为更科学合理地对低温LPG港口、码头进行安全风险分析,对工程实例采用定量风险评估(QRA)、事故后果模拟方法,研究了低温LPG码头的风险,给出了低温LPG码头个人风险曲线。对比了低温LPG码头和常温LPG码头的事故后果影响范围。结果显示,码头低温LPG泄漏后的危害距离是常温LPG泄漏后危害距离的2.7倍以上,低温LPG码头的安全风险高于常温LPG码头的安全风险;低温LPG码头泄漏事故可能影响到邻近码头的安全。提出了降低风险的关键安全对策措施,可有效降低风险约1个数量级。定量风险分析工作是JTS 158—2019《油气化工码头设计防火规范》等标准规范的有益补充,可为LPG码头选址、总平面布置、工艺安全、泄漏事故应急预案提供参考。