基于Landsat 8遥感数据的天津市地表温度反演

以Landsat 8遥感数据为数据源,进行天津市地表温度反演研究。首先采用单通道算法反演地表温度,并利用均值标准差法进行温度分级。然后建立不同温度等级面积比例的估算模型。再通过随机样点,从不同温度等级和土地覆盖类型2个角度,分别建立并比较不同类样点的地表温度与各指数的拟合模型。结果表明:次高温区域面积比例与人口密度、人均GDP都具有较高的决定系数;地表温度与NDVI、BAEM的二元线性回归决定系数高于地表温度与单一指数的决定系数;将样点分类后,低温点与MNDBI的决定系数高于其他温度等级样点,水域和植被样点与各种指数的决定系数高于其他地物类型样点。     

Estimating marine biogeochemical rates of the carbonate pH system—A Kalman filter tested

Oxygen (O₂), nitrate (NO₃), dissolved inorganic carbon (DIC) or pCO₂, and pH or total alkalinity (TA), are useful indices of marine chemical, physical and biological processes operating on varying time-scales. Although these properties are increasingly being monitored at high frequency, they have not been extensively used for studying ecosystem dynamics. We test whether we can estimate time-evolving biogeochemical rates (e.g. primary production, respiration, calcification and carbonate dissolution, and nitrification) from synthetic high frequency time-series of O₂, NO₃, DIC, pCO₂, TA or pH. More specifically, a Kalman filter has been implemented in a very simplified biogeochemical model describing the dynamics of O₂, NO₃, DIC and TA and linking the concentration data to biogeochemical fluxes. Different sets of concentration data are assimilated and biogeochemical rates are estimated. The frequency of assimilation required to get acceptable results is investigated and is compared with the frequency of sampling in the field or in controlled experimental settings.Smoothing of the data to remove data noise before assimilation improves the estimation of the biogeochemical rates. The best estimated rates are obtained when assimilating O₂, NO₃ and TA although the assimilation of DIC instead of TA also gives satisfactory results. In case pH or pCO₂ is assimilated rather than DIC or TA, the linearization of the (now nonlinear) observation equation introduces perturbations and the Kalman filter behaves suboptimal. We conclude that, given the resolution of data required, the tool has potential to estimate biogeochemical rates of the carbonate system under controlled settings.     

气体、粉尘爆炸灾害及其安全技术

对可燃性气体、蒸汽、粉尘的爆炸特性及其抑爆、隔爆安全技术进行了系统的研究 ,并对常见的可燃性气体、蒸汽和粉尘的各种爆炸特性参数和气体抑爆安全技术参数进行了实验测定。根据实验测定结果得到的结论对这种可燃性物质的安全应用具有重要的参考价值     

近断层强震速度脉冲效应及连续梁桥减隔震特性分析

应用非线性时程分析的方法 ,对于减、隔震连续桥梁在近场地震作用下的有效性和响应特性 ,作了深入的研究。通过有代表性的脉冲型近场强震记录时程分析 ,提出了用速度脉冲峰值及其周期之积来表示速度脉冲能量的方法 ,计算表明近场地震速度脉冲波能近似表征地震动破坏能力的大小 ,它和桥梁结构承受的地震响应大体成正比例关系。铅芯橡胶隔震支座在近场地震作用下仍然适用 ,但对于个别脉冲型强震记录效果不够明显 ,支座参数有必要进行优化。     

Strength and tightness evaluation method for pipe flange connections considering thermal effects

The pipe flange connection is widely applied in chemical, power plants, petrochemical, offshore oil and gas industries, and its strength and tightness are significant for the safe operation. However, there are still no practical and applicable strength and tightness evaluation methods for pipe flange connections working in dramatically varying temperatures. This paper proposed an approach to evaluate the pipeline's strength and sealing performance considering thermal effects in actual operating conditions by combining the experimental measurement and thermostructural analysis. The critical thermodynamic parameters are identified through measured temperature data in operating conditions, and then these parameters are used in the thermostructural analysis to obtain the actual temperature and stress fields. Then, the strength and tightness in complex temperature cases can be evaluated accurately. The pipe flange connection of a liquefied natural gas (LNG) fueling station is analyzed to verify the presented method's effectiveness. This method applies to evaluating the pipeline's strength and tightness and can predict the pipeline's performances under extreme temperatures using the tested data within the measurement range and the corresponding thermostructural analysis. Furthermore, the work in this paper also provides a reference for the design and analysis of pipe flange connections working in complex temperature conditions.     

基于裂区设计的大气能见度拟合及预测模型

通过收集分析广州能见度及影响因子数据的特征,使用R-project统计软件作为建模工具,采用多层裂区实验构建模型基本框架,选择影响显著的因子进行变量变形处理,对年、月、日、小时的数据特征进行层层分割设计,并在对应层次引入代表时间含义的虚拟变量以提高模型的表征水平,加入二次项、交叉项等提高模型的精度,得到拟合度高、适用性强的能见度拟合及预测模型。     

等效温度曲线的数值拟合

通风空调工程中,等效温度是衡量气候舒适程度的主要指标.传统的查图法求解等效温度不仅繁琐,而且不准确.本文以等效温度为基础,在等效温度图中取值,运用Matlab拟合数据,并进行坐标变换,求解出干球温度、湿球温度及风速之间的规律,推导出等效温度的数值求解方法.经实例计算和误差分析证明,此数值解法较为准确.     

太湖水质指标相关性与富营养化特征分析

为研究太湖第一阶段治理水质富营养化的特征，根据1999年10月采样数据，对总磷、总氮等与富营养化相关的水质指标进行了统计分析。发现透明度与叶绿素a之间并未表现出显著的相关性，而在聚类图中，悬浮物与总磷、总氮显示出密切关系。指出农村面源仍是太湖中营养物质的重要来源。     

电感耦合等离子体发射光谱法测定地下水中锰的不确定度评定

本文对电感耦合等离子体发射光谱法测定地下水中锰含量的不确定度进行了评定,标准曲线采用双误差拟合法,建立了不确定度评定模型,对测定地下水样品中锰含量的不确定度作了评估。     

完全均匀混合质量平衡水质模型在滇池中的应用

介绍了完全均匀混合假设下以质量平衡为基础的湖泊水质模型,运用滇池的实测数据对模型进行了参数率定、验证,给出了模型在滇池水质预测中的应用实测,最后讨论了模型的几个假设条件对滇池的适应性。实例研究表明,该模型可适用于滇池水质有机污染长期浓度预测。