水体氮浓度、形态对黑藻和狐尾藻光合特征的影响

利用黑藻和狐尾藻研究了水体氮浓度和形态对沉水植物光合特征的影响.结果表明,狐尾藻在TN≤3mg/L、黑藻在TN≤4mg/L范围内其净光合速率、最大净光合速率和暗呼吸速率均随水体总氮浓度的增加而增大,对光合作用有利,超过这个范围时,这两种供试植物的光合作用受到抑制,净光合速率和最大净光合速率降低,暗呼吸速率急剧上升;在本实验条件下,这两种供试植物的光合补偿点和光合饱和点随氮浓度的变化没有表现出规律性.在总氮一定的条件下黑藻和狐尾藻的净光合速率和最大净光合速率均随水中铵氮的增加而降低,暗呼吸速率和光合补偿点随铵氮增加而升高,说明水体铵氮的增加对黑藻和狐尾藻具有一定的毒害作用,抑制了光合作用;在本研究条件下光合饱和点对氮形态比例的变化没有明显的响应.结合我国湖泊N营养现状,可初步推断我国大部分湖泊氮浓度不会对黑藻和狐尾藻的光合作用产生直接的危害,但在水生生态系统的恢复过程中,要根据水生植物对不同氮形态的喜好特性和水质情况选择先锋物种.图2表3参27     

Comparative study of degradation of toluene and methyl isobutyl ketone (MIBK) in aqueous solution by pulsed corona discharge plasma

Effectiveness of pulsed power plasma for the degradation of two toxic volatile organic compounds (VOCs), toluene and methyl isobutyl ketone (MIBK), in aqueous solution was evaluated. The plasma degradation of MIBK has been studied for the first time. The influence of initial concentration of target compound, solution pH and scavengers on percentage degradation was evaluated. 100% removal of 200 mg/L of toluene and MIBK was achieved both in liquid and gaseous phases after 12 and 16 min of plasma treatment, respectively. The first order rate constant of toluene and MIBK degradation (for 200 mg/L each) was 0.421 and 0.319 min^?1 respectively when they were treated individually, and these values decreased slightly during degradation of their mixture. MIBK degradation was slower than toluene and it might be due to semi volatile and hydrophilic nature of MIBK. The effect of initial concentration of toluene and MIBK showed different degradation patterns. Highest degradation of both the compounds was obtained in neutral pH and in absence of scavengers. ?OH radical was the major reactive species involved in their degradation. Their degradation in real environmental matrices showed that removal reduced significantly in secondary effluent due to scavenging of reactive species by various ions and organic matter. The total number of degradation intermediates identified in case of toluene and MIBK was 11 and 14 respectively and formate was the one recalcitrant byproduct generated. The degradation pathway of toluene and MIBK involving reactions of reactive oxygen and nitrogen species and reductive species is proposed.     

Distinct effects of intrinsic motivation and extrinsic rewards on radical and incremental creativity: The moderating role of goal orientations

Previous studies have investigated the role of intrinsic motivation and extrinsic rewards in enhancing employee creativity. However, the possibility that these motivational factors affect the creativity of different types remains largely unexplored, particularly in the organizational settings. Moreover, the potential that personality traits may moderate the function of these motivational factors toward creativity is another underresearched area. By drawing on the person–situation interaction perspective, we propose that both intrinsic motivation and extrinsic rewards predict creativity but of different types. Thus, we diverge from the view that creativity is a uniform criterion domain by adopting the distinction between radical and incremental creativity. Our empirical analysis of 220 independent employee–supervisor dyads confirmed that intrinsic motivation and extrinsic rewards predict radical and incremental creativity, respectively. Moreover, the effects of intrinsic motivation on radical and incremental creativity are more positive for employees with higher learning goal orientation. By contrast, the effect of extrinsic rewards on incremental creativity is more positive for employees with higher performance goal orientation. This study offers elaborate and nuanced perspectives and insights into the role of different motivational processes in the development of different types of creativity.     

顺磁共振法测定气相中OH自由基的研究

采和电子顺磁共振（ＥＰＲ）法测定气相中ＯＨ自由基的研究表明,４＝ＰＯ敢相中ＯＨ交好自旋捕集剂,得到的４－ＰＯＢＮ－ＯＨ加合物稳定性媸,样品避光保存２ｄ后,测得ＥＰＲ谱的峰形和大小不变,测得ＯＨ加合物的ＥＰＲ谱中超精细偶合常数分别为αＮ＝１．４５ｍＴ和αＨβ＝０．２２ｍＴ,除去样品溶液中微量的Ｏ２,将改善ＥＰＲ谱的峰形。还报字用这种方法对上海地区大气中采样实测得到ＯＨ加合物的ＥＰＲ谱,它与实验室模拟     

单原子Co-C-N催化过一硫酸盐降解金橙Ⅱ

采用模板蚀刻法合成单原子Co-C-N催化剂并催化过一硫酸盐(PMS)降解偶氮染料金橙Ⅱ(AO7).考察了催化剂投加量、PMS浓度、pH值和染料废水中常见的Cl-对Co-C-N/PMS体系去除AO7的影响,探讨了体系的反应机理,分析了矿化能力和催化剂重复利用性能.结果表明,在Co-C-N/PMS体系中,反应随着催化剂投加...     

Effects of fulvic acid concentration and origin on photodegradation of polycyclic aromatic hydrocarbons in aqueous solution: Importance of active oxygen

With an Xe arc lamp house as simulated sunlight, the influences of fulvic acid (FA) concentration and origins on photodegradation of acenaphthene, fluorine, phenanthrene, fluoranthene and pyrene in aqueous solution have been studied. Similar effects of FAs, collected from five places around China, on polycyclic aromatic hydrocarbon (PAH) photodegradation have been observed. Active oxygen was of significance in PAH photodegradation with the presence of FAs. For systems with 1.25 mg L⁻¹ FAs, the contributions of OH to PAH photodegradation rates were from 33% to 69%. FAs had two opposite effects, i.e., stimulating the generation of active oxygen and advancing PAH photodegradation; competing with PAHs for energy and photons and restraining PAH photodegradation. Generally, photodegradation rates of the 5 PAHs decreased with the increase of FAs concentration; except fluoranthene and pyrene were advanced in solutions with low FA concentration. The influences of FA concentration on PAH photodegradation were more significant than FA origin.     

The spectroscopic studies of humic acid extracted from sediment collected at different seasons

Gocza?kowice Reservoir is the biggest water reservoir in the south of Poland. For our studies bottom sediments were collected from eight different places of the reservoir at various seasons of the year.EPR spectroscopy was applied to analyse both quantitatively and qualitatively the humic acids (HA) present in the samples. EPR spectra of the extracted HA exhibited broad lines from the paramagnetic metal ions and narrow lines from free radicals. The values of the free radical concentration obtained for HA amounted to 1.14-13.6 × 1016 spin g⁻¹ depending on the season and the place of sample collection. The values of the g factor obtained for HA were of the range 2.0027-2.0035.The EPR studies show that HA extracted from bottom sediment collected at various points of the Gocza?kowice Reservoir exhibit similar physical-chemical properties. It was also observed that the depth of the reservoir affects the content of the oxygen functional groups as well as the free radical concentration in HA.The identification of the functional groups was done by means of IR. UV/VIS spectroscopy was used to estimate the maturity of the HA.     

非自愿性移民生产安置中土地公平补偿研究——以湖南皂市水利枢纽工程为例

水利水电工程建设与移民安置会占用淹没区与安置区土地,根据补偿原理,淹没区与安置区理应获得补偿,从公平角度研究其土地补偿,对于增进移民与安置区居民福祉、实现社会公平正义具有积极意义。本文在界定和讨论淹没区与安置区土地公平补偿内涵与范围的基础上,分析了研究区域现行补偿标准的公平性,采用收益还原法和条件价值法分别测算了淹没区与安置区土地的市场价值与非市场价值,并由此测算土地公平补偿。结果表明:1淹没区与安置区土地公平补偿内涵是"损失什么,补偿什么",采取完全补偿原则,能体现"两区"之间的公平,公平补偿范围包括农地市场价值和非市场价值;2研究区域淹没区和安置区水田的市场价值分别是698 558.18元/hm2和573 272.73元/hm2,旱地为457 090.91元/hm2和465 818.18元/hm2;淹没区和安置区水田的非市场价值为50 006.40元/hm2和52 008.36元/hm2,旱地为47 045.65元/hm2和48 278.08元/hm2。3淹没区水田公平补偿测算结果为748 564.58元/hm2,旱地为504 136.56元/hm2;安置区水田公平补偿为625 281.09元/hm2,旱地为514 096.26元/hm2;4现行淹没区水田和旱地补偿标准仅为测算结果的53.77%和53.80%,安置区的补偿标准更是远低于该测算结果。研究结论:研究区域现行土地补偿标准仅能反映部分农地价值,是不完全补偿,同时,有关补偿制度未将淹没区与安置区土地补偿置于平等地位,现行土地补偿标准有失公平;本文基于农户的福利损失测算土地补偿,体现了公平补偿内涵;在土地补偿政策改进方面,应提高淹没区与安置区土地补偿标准,建立完善的社会保障制度,实施更加积极的就业政策等。     

蒽醌-2-磺酸钠有机体系光引发自由基降解染料

采用蒽醌-2-磺酸钠有机体系光引发自由基降解废水中的染料。分析了蒽醌-2-磺酸钠有机体系光引发自由基降解的机理,考察了曝气、光照强度和初始染料质量浓度等因素对降解效果的影响。实验结果表明：曝气有利于蒽醌-2-磺酸钠有机体系光引发自由基降解染料;在光照强度1 000 W、初始染料质量浓度50 mg/L的条件下,反应60 min后酸性蓝80溶液的脱色率可达100%;在酸性红249、酸性黄42、酸性蓝80、活性艳红KD-8B、活性黄K-6G和活性翠蓝K-NG 6种商用酸性和活性染料中,蒽醌-2-磺酸钠有机体系对活性黄K-6G和活性艳红KD-8B的脱色率最高,对酸性蓝80和活性翠蓝K-NG的脱色率最低。