废气和废渣协同作用脱钠反应特性及机制研究

以氧化铝冶炼过程中排出的碱性固体废渣赤泥为研究对象,利用烟气中CO2对其进行了脱钠工艺的实验分析.研究了在不同pH、反应时间和温度下废气中CO2与废渣赤泥协同作用脱钠反应特性及机制,结果表明,赤泥脱钠反应过程是赤泥中钠基固体物质与CO2-H2O和OH--CO2系统协同作用的结果,脱钠过程与pH值、温度和反应时间有一定的反应规律.采用XRD和SEM方法对赤泥脱钠前后物料特性进行表征分析,结果表明赤泥中的碱性物质与CO2发生反应,赤泥脱钠后固相中的钠含量明显降低.通过合理的设计和适当的操作,可使赤泥脱钠率达70%以上,为低成本赤泥脱钠提供了一种有效的途径.     

Why do house-hunting ants recruit in both directions?

To perform tasks, organisms often use multiple procedures. Explaining the breadth of such behavioural repertoires is not always straightforward. During house hunting, colonies of Temnothorax albipennis ants use a range of behaviours to organise their emigrations. In particular, the ants use tandem running to recruit naïve ants to potential nest sites. Initially, they use forward tandem runs (FTRs) in which one leader takes a single follower along the route from the old nest to the new one. Later, they use reverse tandem runs (RTRs) in the opposite direction. Tandem runs are used to teach active ants the route between the nests, so that they can be involved quickly in nest evaluation and subsequent recruitment. When a quorum of decision-makers at the new nest is reached, they switch to carrying nestmates. This is three times faster than tandem running. As a rule, having more FTRs early should thus mean faster emigrations, thereby reducing the colony’s vulnerability. So why do ants use RTRs, which are both slow and late? It would seem quicker and simpler for the ants to use more FTRs (and higher quorums) to have enough knowledgeable ants to do all the carrying. In this study, we present the first testable theoretical explanation for the role of RTRs. We set out to find the theoretically fastest emigration strategy for a set of emigration conditions. We conclude that RTRs can have a positive effect on emigration speed if FTRs are limited. In these cases, low quorums together with lots of reverse tandem running give the fastest emigration.     

Formaldehyde degradation by UV/TiO2/O3process using continuous flow mode

The degradation of formaldehyde gas was studied using UV/TiO2/O3 process under the condition of continuous flow mode. The effects of humidity, initial formaldehyde concentration, residence time and ozone adding amount on degradation of formaldehyde gas were investigated. The experimental results indicated that the combination of ozonation with photocatalytic oxidation on the degradation of formaldehyde showed a synergetic action, e.g,, it could considerably increase decomposing of formaldehyde. The degradation efficiency of formaldehyde was between 73.6% and 79.4% while the initial concentration in the range of 1.84--24 mg/m^3 by O3/TiO2flJV process. The optimal humidity was about 50% in UV/TiO2/O3 processs and degradation of formaldehyde increases from 39.0% to 94.1% when the ozone content increased from 0 to 141 mg/m^3. Furthermore, the kinetics of formaldehyde degradation reaction could be described by Langmuir-Hinshelwood model. The rate constant k of 46.72 mg/（m^3.min） and Langmuir adsorption coefficient K of 0.0268 m^3/mg were obtained.     

纳米银材料的生物安全性研究进展

纳米银材料被广泛应用到医疗、化工、生物等许多领域,增加了与人类接触的可能性,因此关注其生物安全性是很有必要的。本文对近年来纳米银的抗菌性和生物安全性研究进行了综述。首先分析了纳米银的皮肤毒性、呼吸系统毒性、消化系统毒性和其他组织毒性,其次分析了体外细胞毒性和细胞内纳米银与生物大分子相互作用,最后对纳米银材料的人群暴露生物安全性及纳米银与银离子毒性关系进行了探讨。本文旨在为纳米银的毒性作用机制研究提供参考,为建立标准的纳米银安全性评价体系提供依据。     

Degradation kinetics of tebufenozide in model aquatic systems under controlled laboratory conditions

Abstract

The hydrolysis of the insecticide tebufenozide was studied in the dark at 20 to 40°C in buffered (pH 4 to 10) distilled water, and at 20°C in unbuffered, sterilized and unsterilized stream water. Tebufenozide was very stable in acidic and neutral buffers at 20°C and the corresponding pseudo‐first‐order rate constants (k_obsd) and half‐lives (T_1/2) were 5.946 × 10^‐4 and 13.10 × 10^‐4 d^‐1, and 1166 and 529 d, respectively. The hydrolytic degradation was dependent on pH and temperature. At pH 10 and at 20,30 and 40°C, the k_obsd (10^‐4 d^‐1) and T_1/2 (d) values were 34.22, 66.72 and 130.0; and 203, 104 and 53.3, respectively. The energy of activation (E_a) values for the hydrolysis of tebufenozide at pH 4, 7 and 10, calculated from the Arrhenius plots, were 83.50, 66.71 and 50.87 kJ/mol, respectively. Tebufenozide was stable in sterilized stream water in the dark (T_1/2 = 734 d) but it degraded fairly rapidly in unsterilized stream water (T_1/2 = 181 d). Sunlight photodegradation of the chemical was slower (T_1/2 = 83.0 h) than the photolysis by ultraviolet radiations (T_1/2 values at 254 and 365 nm were 9.92 and 27.6 h, respectively); nevertheless, it was still appreciable during the summer months at 46°31’ N latitude. The differences in degradation rates between the unsterilized and sterilized stream water and the degradation of the chemical in the sterile, distilled water in sunlight, suggests that microbial processes and photolysis are the two main degradative routes for tebufenozide in natural aquatic systems.     

铁路编组站劳动安全联防联控可靠性模型及应用研究

从个人和群体的可靠性出发，建立了铁路编组站劳动安全联防联控的可靠性模型，论证了联防联控的可行性，提出了实施重点及对策。     

试析环境监测工作的基础

要搞好环境监测工作 ,必须解放和发展环境监测生产力 ,履行“政府行为” ,贯彻“稳住一片 ,放开一头”的政策。环境监测工作具有政府行为组成的三种必备要素和五个特点 ;“稳住一片 ,放开一头”是因为环境监测所具有的本质属性、社会属性和法律属性     

Development of plans to restore degraded areas in the Great Lakes

The International Joint Commission's Water Quality Board has identified 42 Areas of Concern in the Great Lakes ecosystem where Great Lakes Water Quality Agreement objectives or jurisdictional standards, criteria or guidelines, established to protect uses, have been exceeded and remedial actions are necessary to restore beneficial uses. As a result of the 1985 report of the Water Quality Board, the eight Great Lakes states and the Province of Ontario committed themselves to developing a remedial action plan (RAP) to restore all uses in each Area of Concern within their political boundaries. Each RAP must identify the specific measures necessary to control existing sources of pollution, abate existing contamination (e.g., contaminated sediments), and restore all beneficial uses. Points which must be explicitly addressed in each RAP include: geographic extent of problem, beneficial uses impaired, causes of problems, remedial measures and a schedule for implementation, responsible agencies, and surveillance and monitoring activities that will be used to track effectiveness of remedial actions. The jurisdictions are responsible for developing RAPs, and the International Joint Commission is responsible for evaluating the adequacy of each RAP and tracking progress in restoring beneficial uses.     

消费端食物浪费：影响与行动

食物浪费已经成为全球性问题,引发社会各界广泛关注。消费端是造成食物浪费的重要环节,且呈日趋严重的趋势。消费端的食物浪费主要分为家庭食物浪费和在外食物浪费;消费端的食物浪费对国家粮食安全、资源环境、社会经济发展等方面均产生不同的影响;影响消费端食物浪费的重要因素包括社会经济发展水平、文化因素、人口特征、消费者的行为与意识等。目前对消费端食物浪费的研究多采用称重（或估算）和计量模型等方法,仍需要通过发展更合理的量化方法、建立更完整的理论模型、提出更完善的研究方法进行深入探究。此外,减少消费端食物浪费需要从政府、社会、个人等多角度出发,促使多方利益相关者形成合力应对消费端食物浪费问题。     

基于居民行为的三生空间识别与优化分析框架

“三生空间”是人类经济、社会活动的基本载体,也是人类精神和文化需求的空间反映。识别“三生空间”范围、了解居民“三生”需求、调整“三生空间”供给、统筹“三生空间”功能是国土空间规划内容的核心,也是当前实现治理能力现代化和新时代高质量发展的重要前提。从当前国土空间规划编制的需求出发,依据行为科学和行为地理学等理论方法,探讨了“三生行为”与“三生空间”的理论关联,进而遵循“需求分析与空间识别—问题诊断与目标确定—作用机理与耦合关系—空间优化与政策建议”分析思路,构建基于居民行为的“三生空间”优化分析框架。将居民行为研究与空间供需结合起来,可为国土空间规划工作提供“人本化”的理论框架与新思路。