进口废五金类加工利压定点企业管理研究

随着我国进口废物环境管理与政策的完善,进口废五金电器、废电线电缆、废电机定点加工利用企业管理逐步完善,但仍存在行业技术装备水平和管理规范性低等问题。本文详述了定点企业生产布局、生产设备、污染治理设施及管理制度的现状及存在问题,并提出相应的建议,为进1：2废五金类企业的发展提供指导依据。     

基于图像感兴趣区域融合特征的PM2.5浓度预测方法

通过图像预测PM_2.5浓度的准确性,在很大程度上取决于模型所选用的特征参数。为丰富特征参数的表达,设计了一种基于图像传统特征与深度特征充分融合的PM_2.5浓度预测方法。首先,根据不同PM_2.5浓度下的成像差异,选定图像感兴趣区域,解决图像尺寸过大导致的模型运算效率较低问题。然后,针对所选取的局部图像,利用传统图像处理方法手动设计并提取图像浅表视觉特征,同时利用卷积神经网络自动提取图像深层语义特征。最后,将两种特征融合,交由卷积神经网络的全连接层实现对PM_2.5浓度的回归预测。预测误差比对结果显示,相比使用单种特征,使用融合特征能够有效提高模型的预测性能。     

Equilibrium Prices in a Vertically Coordinated Fishery

Competition among processing firms is analyzed in a fishery that is managed under a total allowable catch constraint. Firms compete first in the ex-vessel market for round fish and then in the downstream consumer market. Nash equilibrium prices are characterized at each stage of the vertical market. When the number of processors is sufficiently large, equilibrium prices are approximately Walrasian. The ex-vessel price is close to the processor marginal valuation of the round fish and the consumer price clears the total quantity of processed fish. Implications for market structure, conduct and performance, and fisheries management policy are drawn.     

Using hidden Markov chains and empirical Bayes change-point estimation for transect data

Consider a lattice of locations in one dimension at which data are observed. We model the data as a random hierarchical process. The hidden process is assumed to have a (prior) distribution that is derived from a two-state Markov chain. The states correspond to the mean values (high and low) of the observed data. Conditional on the states, the observations are modelled, for example, as independent Gaussian random variables with identical variances. In this model, there are four free parameters: the Gaussian variance, the high and low mean values, and the transition probability in the Markov chain. A parametric empirical Bayes approach requires estimation of these four parameters from the marginal (unconditional) distribution of the data and we use the EM-algorithm to do this. From the posterior of the hidden process, we use simulated annealing to find the maximum a posteriori (MAP) estimate. Using a Gibbs sampler, we also obtain the maximum marginal posterior probability (MMPP) estimate of the hidden process. We use these methods to determine where change-points occur in spatial transects through grassland vegetation, a problem of considerable interest to plant ecologists.     

南安市石材加工业污染现状及对策

就南安市石材加工业的基本情况及对环境污染现状进行调查和综述，并提出防治对策。     

Phosphorus recovery from wastewater by struvite crystallization：Property of aggregates

Struvite crystallization is a promising method to remove and recover phosphorus from wastewater to ease both the scarcity of phosphorus rock resources and water eutrophication worldwide. To date, although various kinds of reactor systems have been developed, supporting methods are required to control the struvite fines flushing out of the reactors. As an intrinsic property, aggregation is normally disregarded in the struvite crystallization process, although it is the key factor in final particle size and therefore guarantees phosphorus recovery efficiency. The present study developed a method to analyze the characteristics of struvite aggregates using fractal geometry, and the influence of operational parameters on struvite aggregation was evaluated. Due to its typical orthorhombic molecular structure, struvite particles are prone to crystallize into needle or rod shapes, and aggregate at the corners or edges of crystals. The determined fractal dimension(Dpf) of struvite aggregates was 1.52–1.31, with the corresponding range of equivalent diameter(d0.5) at 295.9–85.4 μm. Aggregates formed in relatively low phosphorus concentrations(3.0–5.0 mmol/L) and mildly alkaline conditions(pH 9.0–9.5) displayed relatively compact structures, large aggregate sizes and high aggregation strength. Increasing pH values led to continuous decrease of aggregate sizes, while the variation of Dpfwas insignificant. As to the aggregate evolution, fast growth in a short time followed by a long steady stage was observed.     

某型飞机典型结构危险部位地面停放预腐蚀影响系数曲线的试验测定

目的评定飞机日历寿命,测定飞机典型结构件的地面停放系数随日历年限的变化规律(C-T曲线)。方法针对典型飞机结构连接件,首先在实验室条件下采用加速腐蚀的预腐蚀试验及预腐蚀后的疲劳试验,得到不同加速当量腐蚀年限下的疲劳寿命,然后对疲劳试验数据进行统计及处理。结果最后拟合得到飞机典型结构件的地面停放系数随日历年限的变化规律曲线。结论通过C-T曲线可为某型飞机的定寿提供基础。     

落差指数法的Matlab实现及其在大通水文站的应用

河流水位与流量的关系曲线常表现为单一或复式绳套,而对流量进行单值化处理后,则可获得与水位之间确定的函数关系,从而可以提高在受潮汐影响时推流精度,为实际工作中的水文资料整编带来可靠方法.在明确落差指数法数学原理的基础上,编写了相应的Matlab函数datong_Q.m.并且以大通水文站2008年-2012年实测的水位和流量为例,获得该段时期内的对应参数.与目前工作中采用的连时序法相比,单值化方法在结果精确的同时,还具有求解方便、计算快捷等特点,因而具有较强的实际应用价值.