小波分析在PM10浓度时间序列分析中的应用

以西安市PM10日平均浓度时间序列为例,根据小波分析的基本原理,应用小波分解和重构对PM10浓度时间序列的变化进行了分析,得到PM10的年变化趋势和突变特征。研究结果表明,用小波分析应用于大气污染物浓度时间序列的分析是可行的。     

总磷测试消解方法的改进

用过氧化氢-沸水浴消解法测定水样中的总磷,结果表明,新消解方法具有操作简单,消解完全的特点,与传统方法具有良好的可比性,精密度和准确度均令人满意。     

Effect of cerium on photosynthetic characteristics of soybean seedling exposed to supplementary ultraviolet-B radiation

Effects of cerium （Ce^3＋） on photosynthetic characteristics were investigated by hydroponics under laboratory conditions when soybean seedlings were exposed to two levels of supplementary UV-B radiation. UV-B radiation badly inhibited the photosynthesis in soybean seedling, leading to a reduction in net photosynthetic rate （Pn）, Hill reaction activity, light saturated photosynthetic rate （Ps） and apparent quanta yield （AQY）, as well as the CO2 and light saturated photosynthetic rate （Pro） and carboxulation efficiency （CE）. On the contrary, Ce obviously promoted the photosynthesis of plants by increasing Hill reaction activity, accelerating electron transport and photophosphorylation, and enhancing carboxylation efficiency. For Ce＋UV-B treatments, the values of photosynthetic parameters were still lower than those of the control, but obviously higher than those of UV-B treatment. The results indicated that Ce alleviated the inhibition of UV-B radiation on the photosynthesis in soybean seedling to a certain extent. In correlating of Pn with Hill activity, AQY and CE, we found that the changes of photosynthetic rate were mainly influenced by the regulating effect of Ce on Hill activity and AQY at low level （0.15 W/m^2） of UV-B radiation, but were dominated by the regulating effect of Ce on CE at high level （0.45 W/m^2）. Thus, Ce could regulate many aspects in photosynthesis of soybean seedling under UV-B stress. The regulating mechanism was close related with the dosage of UV-B radiation.     

Spatial and temporal relationships between precipitation and ANPP of four types of grasslands in northern China

Precipitation is considered to be the primary resource limiting terrestrial biological activity in water-limited regions. Its overriding effect on the production of grassland is complex. In this paper, field data of 48 sites （including temperate meadow steppe, temperate steppe, temperate desert steppe and alpine meadow） were gathered from 31 published papers and monographs to analyze the relationship between above-ground net primary productivity （ANPP） and precipitation by the method of regression analysis. The results indicated that there was a great difference between spatial pattern and temporal pattern by which precipitation influenced grassland ANPP. Mean annual precipitation （MAP） was the main factor determining spatial distribution of grassland ANPP （r^2 = 0.61, P 〈 0.01）; while temporally, no significant relationship was found between the variance of AN PP and inter-annual precipitation for the four types of grassland. However, after dividing annual preeipitation into monthly value and taking time lag effect into account, the study found significant relationships between ANPP and precipitation. For the temperate meadow steppe, the key variable determining inter-annual change of ANPP was last August-May precipitation （r^2 = 0.47, P = 0.01）; for the temperate steppe, the key variable was July precipitation （r^2 = 0.36, P = 0.02）; for the temperate desert steppe, the key variable was April-June precipitation （r^2 = 0.51, P 〈 0.01）; for the alpine meadow, the key variable was last September-May precipitation （r^2 = 0.29, P 〈 0.05）. In comparison with analogous research, the study demonstrated that the key factor determining inter-annual changes of grassland ANPP was the cumulative precipitation in certain periods of that year or the previous year.     

煤岩电磁辐射信号时间序列混沌特性分析

采用华丰矿1409工作面电磁辐射观测数据,应用相空间重构法计算了5次矿震前后系统混沌吸引子的关联维数D2。研究结果表明:电磁辐射时间序列具有混沌特征,混沌系统的自由度在2~26之间。矿震发生前,混沌吸引子的关联维数D2先升后降,矿震过程中系统有降维现象。研究结果对认识矿震过程中煤岩体产生的电磁辐射信号的非线性特征和进行矿震预报具有一定的参考价值。     

民居内燃气泄漏爆炸特性及其数值仿真研究进展

为研究民居内可燃气体爆炸规律及特点,预防燃气泄漏爆炸案/事件发生,提高案/事件现场勘验与侦破效率,综述受限空间内燃气爆炸的形成机理和传播特性、现场结构和障碍物对爆炸的影响规律以及爆炸后现场勘验和重建技术方法,阐述数值仿真技术在气体爆炸案件现场勘验和重建中发挥的作用。研究结果表明：民居内燃气爆炸现场特征明显异于传统爆炸类案件现场,尤其是炸点特征存在差异;数值仿真可有效揭示燃气泄漏爆炸的形成、传播和作用机理;目前,燃气爆炸实验研究方法和体系需进一步统一,以提高研究结论普适性。研究结果可为民居内燃气爆炸现场勘验和重建提供技术支持。     

Bioavailability of Metals in Fly Ash and Their Bioaccumulation in Naturally Occurring Vegetation: A Pilot Scale Study

A pilot scale study was conducted to find out the different forms of metals if fly ash (FA) and bioaccumulation of these metals in the naturally growing vegetation on FA dumps. The total, acid extractable, bioavailable and water soluble fraction of metals of Fe, Cu, Mn, Zn, Ni, Co and Pb, and their bioaccumulation coefficients (BAC) on naturally growing vegetation were determined. FA samples had a neutral pH, low electrical conductivity, low organic C and trace amounts of N and P. The relative abundance of total metals in FA were found in the order Fe ≤ ≤ Zn ≤ Ni ≤ Co ≤ Cu. The concentration of bioavailable (DTPA) metals depend on the type and nature of coal used in thermal power stations. In the water the extract solution, only Fe and Zn were found above detection limits. After one year only four species of naturally occurring herbaceous vegetation were found growing and Cynodon dactylon (grass) covered almost entire surface of the FA. Iron accumulated to the greatest extent in vegetation followed by Mn, Zn, Cu, Pb, Ni and Co. The sequence of BAC for different metals were Fe (202) ≤ Mn (90) ≤ Zn (63) ≤ Pb (49) ≤ Ni (41) ≤ Cu (24). The experimental study revealed that Cynodon grass could be used for remediation of fly ash without any amendments, as this grass species act as metal excluder type.     

对新疆某铀伴生煤矿辐射环境影响分析及污染防治探讨

通过对新疆某煤矿辐射环境影响问题的调查与分析,阐明铀伴生煤矿对周围环境存在着不同程度的放射性影响,并在调查与分析的基础上,针对调查煤矿日前存在的问题提出了一些污染防治的对策和措施,以期为今后伴生放射性煤矿的环境管理决策提供有力依据。     

某铁路站区供热系统节能技术改造效果评估

针对某车站供暖成本升高和污染物排放等问题,从热源改造和建筑维护结构改造2个方面提出节能技术改造方案,通过对机组运行情况和围护结构改造情况的现场测试,得到节能技术改造效果良好的结论,并从节能效益、经济效益和环保效益3个方面对站区节能技术改造方案效果进行分析.     

环境影响评价在矿区生态重建中的应用

根据我国矿业生产现状,提出了矿区环境影响评价的概念,给出了适合矿区环境评价的方法,并指出矿区环境影响评价在我国矿区生态重建的重要作用.