甘油基混合培养物合成PHA及其与OUR的关系

聚β羟基烷酸盐(PHA)以其较好的生物相容性、可生物降解性和再生性成为最有前途的生物高分子材料.本文基于甘油作为基质在饱食-饥饿模式下富集合成PHA的混培物,以乙酸、丙酸、丁酸、乳酸和葡萄糖作为基质考察混培物合成PHA的基质广谱性,结果表明乳酸和乙酸作为基质时PHA的产率系数较高;使用不同比例乙酸/丙酸混合基质时,PHA产量随着乙酸含量的增加而增大,乙酸/丙酸为3∶1时PHA产量最高.通过活性污泥同时贮存与生长模型模拟与线性回归两种方法证实,在单一基质或乙酸/丙酸混合基质情况下,PHA合成速率与OUR存在线性关系,因此,基于在线OUR测量数据可以实时估计PHA合成量.     

1987-2006年厦门市土地利用变化检测分析

通过对厦门市五个时相的土地利用变化检测,分析了厦门市1987年-2006年间各分区的土地利用变化及各地类在各年间的变化情况,并分析其变化原因.     

油品装卸过程静电特性研究

为了研究油品装卸过程中的静电危险性,在两个城市的油库和加油站对油品的装油、卸油过程,以及装油的油罐车从油库向加油站行驶的过程中,油罐车内油品的油面电位进行了静电检测。通过对大量油罐车内油面电位的检测数据分析可以看出,在正常装卸油过程中,油罐车内油品的油面电位远远小于标准所规定安全油面电位,有缩短稳油时间的可能性。     

胞外聚合物磷酸盐形态对生物除磷过程的影响研究

以不同DO条件下污泥龄(SRT)分别为10 d和30 d的两组实验室A/O-SBR反应器活性污泥为研究对象,探讨了胞外聚合物(EPS)磷酸盐形态对生物除磷过程的影响.结果表明,污泥絮体中的磷主要分布于EPS中,PO3-4-P和聚磷酸盐(Poly-P,包括低分子量聚磷酸盐LMW PolyP和高分子量聚磷酸盐HMW Poly-P)是EPS磷的主要形态;EPS对生物除磷的影响明显大于细菌细胞,EPS磷的厌氧降低量和好氧升高量为胞内磷变化量的2.8~6.4倍.EPS中的LMW Poly-P和HMW Poly-P含量均表现厌氧降低和好氧升高的变化规律;对于相同SRT的污泥,中DO(2.5~3.5 mg·L-1)条件较低DO(0.7~1.0 mg·L-1)条件下EPS的LMW Poly-P和HMW Poly-P有更大的厌氧降低量和好氧升高量,对应着更明显的生物除磷过程,说明EPS不仅是生物除磷过程的中转站,而且参与了生物聚磷过程.     

体育馆出口疏散能力的实验研究

为研究出口单位流量与人流时间之间的关系,以某体育馆为例,进行对某一出口常态下的人流观测实验.通过理论计算和建立Cubic回归模型对采集数据进行了统计分析.发现:单位出口流量最大值为2人/(m·s),稳定值为0.8-1.2人/(m·s),最小值为0.2人/(m·s).出口单位流量是人流时间的三次函数.研究结果表明:出口单位流量是随着时间的变化而变化,不是一个定值,而且单位出口流量稳定值分布在初期.本文对性能化防火设计有一定的参考价值.     

A NEW LOOK AT FLOOD RISK DETERMINATION1

ABSTRACT: The probability distributions of annual peak flows used in flood risk analysis quantify the risk that a design flood will be exceeded. But the parameters of these distributions are themselves to a degree uncertain and this uncertainty increases the risk that the flood protection provided will in fact prove to be inadequate. The increase in flood risk due to parameter uncertainty is small when a fairly long record of data is available and the annual flood peaks are serially independent, which is the standard assumption in flood frequency analysis. But standard tests for serial independence are insensitive to the type of grouping of high and low values in a time series, which is measured by the Hurst coefficient. This grouping increases the parameter uncertainty considerably. A study of 49 annual peak flow series for Canadian rivers shows that many have a high Hurst coefficient. The corresponding increase in flood risk due to parameter uncertainty is shown to be substantial even for rivers with a long record, and therefore should not be neglected. The paper presents a method of rationally combining parameter uncertainty due to serial correlation, and the stochastic variability of peak flows in a single risk assessment. In addition, a relatively simple time series model that is capable of reproducing the observed serial correlation of flood peaks is presented.     

ANALYSIS AND MODELING OF LONG-TERM STREAM TEMPERATURES ON THE STEAMBOAT CREEK BASIN,OREGON: IMPLICATIONS FOR LAND USE AND FISH HABITAT1

ABSTRACT: Steamboat Creek basin is an important source of timber and provides crucial spawning and rearing habitat for anadromous steelhead trout (Oncorhynchus mykiss). Because stream temperatures are near the upper limit of tolerance for the survival of juvenile steelhead, the possible long-term effect of clear-cut logging on stream temperatures was assessed. Twenty-year (1969–1989) records of summer stream temperature and flow from four tributaries and two reaches of Steamboat Creek and Boulder Creek (a nearby unlogged watershed) were analyzed. Logging records for the Steamboat Creek basin and air temperature records also were used in the analysis. A time-series model of the components of stream temperature (seasonal cycle of solar radiation, air temperature, streamflow, an autoregressive term of order 1, and a linear trend variable) was fitted to the water-temperature data. The linear trend variable was significant in all the fitted models except Bend Creek (a tributary fed by cool ground-water discharge) and Boulder Creek. Because no trends in either climate (i.e., air temperature) or streamflow were found in the data, the trend variable was associated with the pre-1969 loss and subsequent regrowth of riparian vegetation and shading canopies.     

非时序加权灰色关联分析在环境质量综合评价中的应用

本文根据灰色关联分析的基本性质，提出一种环境质量综合评价的新方法。该方法用待评价样本各指标值组成参考数列，环境质量分级标准值组成被比较数列，通过计算参考数列与被比较数列的关联度，按最优关联识别原则综合评价环境质量等级。用４个实例与其它方法进行了对比，取得满意的效果。     

MFAM模型在河流水质污染模拟及预测中的应用

文中以时间序列分析为基础，介绍了均值生成函数这一崭新概念，并且经成份因子提取分析推导建立了模拟序列的数字模型（简记为MFAM），经对黄河下游花园口断面的1988-1989年实测水质污染指标溶解氧（DO），氨氧，化学耗氧量（COD），五日生化需氧量（BOD5）等序列模拟，结果表明MFAM模型能较好地模拟河流水质污染指标的变化趋势，拟合平均误差只有5.2-6.4%，MFAM模型应用于预测1990-1991年水质污染指标变化，结果表明预测精度达85%以上，文中最后得出结论：MFAM模型应用于河流污染模拟和预测，是完全可行且十分方便。     

BAYESIAN MODELS OF FORECASTED TIME SERIES1

Bayesian Processor of Forecasts (BPF) combines a prior distribution, which describes the natural uncertainty about the realization of a hydrologic process, with a likelihood function, which describes the uncertainty in categorical forecasts of that process, and outputs a posterior distribution of the process, conditional upon the forecasts. The posterior distribution provides a means of incorporating uncertain forecasts into optimal decision models. We present fundamentals of building BPF for time series. They include a general formulation, stochastic independence assumptions and their interpretation, computationally tractable models for forecasts of an independent process and a first-order Markov process, and parametric representations for normal-linear processes. An example is shown of an application to the annual time series of seasonal snowmelt runoff volume forecasts.