SDS对烟煤润湿性能和机理的分子模拟研究

为探究十二烷基硫酸钠(SDS)对烟煤的润湿机理,首先通过实验分析SDS对烟煤润湿性能影响,然后利用分子模拟对SDS在烟煤表面的润湿过程进行研究。研究结果表明：SDS溶液改善烟煤的润湿性能,全尘、呼吸性粉尘降尘效率分别比纯水提高7.95%和10%;根据轨道能级差和静电势分析得出,SDS分子尾链吸附烟煤表面、头基朝向水中的吸附构型降低水和烟煤的液-固界面张力;SDS分子覆盖烟煤表面后,系统中烟煤与水分子的非键作用能、氢键数量、水分子的起始位点分别由-1 114.91 kcal/mol, 1 810个,1.59?变为-3 405.68 kcal/mol, 1 996个,1.57?,在SDS分子的作用下烟煤表面与水分子结合能力变强,大量水分子通过氢键作用凝聚在头基附近,水分子整体移向烟煤使烟煤表面得到充分的浸润和渗透。研究结果可为新型表面活性剂润湿煤尘性能检验提供参考。     

土地资源优化配置与土壤质量调控的系统动力学分析

土地资源优化配置及其环境效应已成为土地科学研究与保障国民经济持续健康发展的重要课题. 运用系统动力学方法,结合土壤质量调查评价,探讨江苏省无锡市区土地资源优化配置与土壤质量调控问题. 结果表明:经济社会发展目标与模式在很大程度上决定着土地资源配置格局,并进一步影响到区域生态环境条件和土壤质量;在经济发展优先模式下,无锡市区建设用地扩张迅速,环境负荷加重,粮食产量降低,2030年的综合土壤质量指数比2005年下降1.50;在生态保护优先模式下,无锡市区土地资源的人口承载压力趋缓,建设用地占用耕地现象得到有效控制,粮食产量较稳定,2030年的综合土壤质量指数仅比2005年下降0.57;未来土地资源配置格局应该以生态保护和提高土地资源配置的综合效益为调控重点.      

三江平原小叶章湿地系统硫的输入及输出动态

以三江平原小叶章(Calamagrostis angutifolia)湿地系统为研究对象,应用野外原位观测法研究了小叶章湿地系统硫的大气沉降输入及其输出规律.结果表明大气湿沉降中硫的月均含量变化明显,其原因主要与人类活动、降水强度及频次有关;硫沉降量具有明显的月变化特征,经估算三江平原小叶章湿地硫的年沉降总量(以S计)为113 mg·m-2·a·-1.小叶章湿地H2S、COS的排放通量均具有明显的季节和日变化规律.H2S和COS的平均释放通量(以S计)分别为O.34 μg·m-2·h-1和-0.29μg·m-2·h-1;小叶章湿地系统在生长季向大气排放H2S的量(以S计)为1.42 mg·m-2,从大气吸收COS的量(以S计)为1.83 mg·m-2.小叶章湿地系统硫的输入量远高于硫输出量,其差值为113.41 mg.m-2·a-1,这表明硫在小叶章湿地系统中处于累积状态,湿地存在潜在的酸化趋势.     

Sex pheromone communication of tentiform leaf-miners <Emphasis Type="Italic">Phyllonorycter insignitella</Emphasis> and <Emphasis Type="Italic">Ph. nigrescentella</Emphasis> from two related species groups

Summary.  Females of both species start their pheromone-releasing activity on the second day after emergence at the beginning of the photophase. During the present work, a peak of calling activity with close to 100% of active Ph. nigrescentella females was registered 1.5 hour after the light had been put on. The high pheromone release behaviour with 50% active females lasted for 3 hours. The calling activity of the group of females was about 6 h/day. The beginning of a photophase under laboratory conditions or an early morning in nature is a common period for sex pheromone release in the genus Phyllonorycter. (8Z,10E)-tetradecadien-1-yl acetate (8Z,10E-14:Ac), (8Z,10E)-tetradecadien-1-ol (8Z,10E-14:OH) and (8E,10Z)-tetradecadien-1-yl acetate (8E,10Z-14:Ac) in the ratio 96:4:traces as well as 8Z,10E-14:Ac and 8Z,10E-14:OH in the ratio 88:12 collected by Solid Phase Micro Extraction (SPME) were found to be specific for the calling periods of virgin Phyllonorycter insignitella and Ph. nigrescentella females respectively. Field trapping experiments demonstrated that all three compounds are important for the attraction of Ph. insignitella males while only 8Z,10E-14:Ac is the essential sex pheromone component for Ph. nigrescentella. The pheromone activity of all three compounds is reported for the first time. Addition of either 8Z,10E-14:OH or 8E,10Z-14:Ac to 8Z,10E-14:Ac did not have a significant effect on the attraction of Ph. nigrescentella males, while the efficiency of the three component blend was 5 times lower as compared to that of 8Z,10E-14:Ac. Our data demonstrate that 8Z,10E-14:OH and 8E,10Z-14:Ac play a dual function, they are minor sex pheromone components of Ph. insignitella essential for attraction of conspecific males and show an allelochemical, antagonistic effect on Ph. nigrescentella males and, thus, ensuring specificity of the mate location signal in two related Phyllonorycter species.     

铜绿微囊藻和斜生栅藻生长的氮营养动力学特征

利用批量培养试验比较研究了氮限制条件下铜绿微囊藻(Microcystis aerugiuosa)和斜生栅藻(Scendesmus obliquus)对氮的生长反应,并应用Monod方程计算了2种藻的营养动力学参数(μ_max和K_s). 结果表明,ρ(氮)为0～2.00 mg/L时铜绿微囊藻比增长率快速增长;ρ(氮)为0～4.00 mg/L时斜生栅藻比增长率快速增长. 铜绿微囊藻的最大比增长率(μ_max)为0.23 d-1,半饱和常数(K_s)为0.14 mg/L;斜生栅藻的μ_max为0.41 d-1,K_s为0.24 mg/L. 根据生长动力学参数可以预测,当氮缺乏时,铜绿微囊藻容易形成优势,当氮丰富时,斜生栅藻容易形成优势.      

Pollution perception: A challenge for intergenerational equity

In this article we extend the recent literature on overlapping generations and pollution by allowing generations to perceive the level of pollution differently than the actual level of pollution. We call this pollution perception. Pollution perception can visualize itself as either a concern for the flow of pollution only, or for the stock, or a combination of both. We derive this extension based on empirical evidence from recent advances in behavioural economics.Pollution perception has not only significant consequences for the steady state levels of pollution and capital, but we also find a qualitative change in the dynamics from similar models without pollution perception [A. John, R. Pecchenino, An overlapping generations model of growth and the environment, Econ. J. 104 (1994) 1393–1410]. Specifically, we derive optimal non-linear dynamics through complex eigenvalues and Hopf or Flip bifurcations for a large set of parameters. This leads to violations of two standard criteria of sustainability, suggesting that pollution perception can be another source of intergenerational inequity.     

Soil drying in a tropical forest: Three distinct environments controlled by gap size

Soil water and temperature regimes in the tropical moist forest on Barro Colorado Island, Panama, were simulated directly from meteorological data using the model SWEAT. Separate field observations from root-exclusion, litter-removal and control treatments in one small and one large forest gap were used for calibration and validation. After irrigating all treatments to field capacity, soil matric potential and temperature were measured over 17 days at four depths ≤50 mm using the filter-paper technique and bead thermistors. Understorey environments were also simulated under the same initial conditions. The results suggest that three distinct scenarios, controlled by gap size, describe how the above- and below-ground processes controlling soil drying are coupled: (1) in the large gap, root water extraction by surrounding trees is negligible so soil drying is dominated by evaporation from the soil surface. Soil temperature is dominated by direct solar heating and cooling due to evaporation. (2) In the small gap, root water extraction dominates soil drying with soil evaporation playing a minor role. Soil temperature is still dominated by direct sunlight with some cooling due to evaporation. (3) In the understorey, root water extraction dominates soil drying. Soil temperature is dominated by heat conduction from deep soil layers with some evaporation and sensible heat transfer. The contrasting soil drying regimes imposed by variation in canopy structure enhance micro-environmental heterogeneity and the scope for differential germination and seedling establishment in coexisting tropical tree species.     

A finite element method to solve a population dynamics stage-structured model of intertidal barnacles

Many marine organisms are fixed or highly sedentary as adults but the adult population may be strongly dependent on the oceanic transport of planktonic larvae. In order to assess interactions between oceanographic and biological processes that determine the population dynamics of marine organisms with a sessile adult phase restricted to the coastline and a planktonic larval phase, we present a stage-structured finite element model for the barnacle Balanus glandula that inhabits the rocky intertidal zone of central California, USA.     

Structure of the social network and its influence on transmission dynamics in a honeybee colony

Infectious processes in a social group are driven by a network of contacts that is generally structured by the organization arising from behavioral and spatial heterogeneities within the group. Although theoretical models of transmission dynamics have placed an overwhelming emphasis on the importance of understanding the network structure in a social group, empirical data regarding such contact structures are rare. In this paper, I analyze the network structure and the correlated transmission dynamics within a honeybee colony as determined by food transfer interactions and the changes produced in it by an experimental manipulation. The study demonstrates that widespread transmission in the colony is correlated to a lower clustering coefficient and higher robustness of the social network. I also show that the social network in the colony is determined by the spatial distribution of various age classes, and the resulting organizational structure provides some amount of immunity to the young individuals. The results of this study demonstrates how, using the honeybee colony as a model system, concepts in network theory can be combined with those in behavioral ecology to gain a better understanding of social transmission processes, especially those related to disease dynamics.     

H2O超声过程中H2O2生成动力学

采用50kHz超声清洗槽式声化学反应器,以纯水为空化液体,研究了超声过程中H2O2生成动力学．分别探讨了空化气体种类(Ar,O2)及组成与流量、空化液体体积与反应器形状对H2O2生成速率及产率的影响．结果表明,超声过程中H2O2的生成可采用零级反应动力学方程来进行描述．在此频率下和考察范围内,采用Ar作为空化气体比O2更有利于H2O2的生成．当混合气体组成为Ar:O2=70：30(V/V)时,H2O2的生成速率最快．随着空化气体流量的增加,H2O2产率增加,随后降低．增加空化液体的体积,H2O2的生成速率降低．与锥形瓶相比,圆底烧瓶中H2O2的产率明显降低．