洞庭湖镉迁移转化的马尔可夫模型评价

讨论了在现时泥沙、水体、鱼类、藻类的含镉状态下洞庭湖的输入输出通量；并以其为例，在简要介绍马尔可夫链数学方法的基础上，建立了湖泊生态系统中镉迁移转化的马尔可夫链数学模型，初步评价了当洞庭湖不断有镉加入、系统到达状态稳定时各种介质中的镉总量及镉的迁移转化趋势。     

Gibbs sampler by sampling-importance-resampling

Among the Markov chain Monte Carlo methods, the Gibbs sampler has the advantage that it samples from the conditional distributions for each unknown parameter, thus decomposing the sample space. In the case the conditional distributions are not tractable, the Gibbs sampler by means of sampling-importance-resampling is presented here. It uses the prior density function of a Bayesian analysis as the importance sampling distribution. This leads to a fast convergence of the Gibbs sampler as demonstrated by the smoothing with preserving the edges of 3D images of emission tomography.     

大型天然水体的环境效应研究

结合典型实例,论述大型天然水体－－堰塞湖从形成到消亡过程中产生的灾害链和环境效应链,包括堰塞湖的淹没、边岸再造、堰塞沉积物、次生洪水、永久性不良地质环境的灾害和环境效应对人民生命财产的威胁,以及对水利水电、航运、公路和铁路工程的不良影响。     

A tool for ROV-based seabed friction measurement

This paper describes a new device for measuring seabed sliding resistance in situ, and provides an associated interpretation procedure. The device is designed to use a work class ROV as a testing platform to allow measurements to be obtained without use of a specialized geotechnical survey platform. The measurements are to assist pipeline design or analysis of the sliding resistance of other on-bottom infrastructure such as anchor chains. The device has been trialled using three tools: a flat plate, a cylindrical pipe section and a length of chain. The tools are dragged axially along the seabed using the ROV thrusters or a separate hydraulic actuator. An interpretation technique has been developed to estimate the passive resistance mobilized by the faces of the tools to eliminate end effects and to account for shape effects such as wedging. Onshore-trial tests were performed in a bed of dry sand. The individual tools exhibited different overall coefficients of friction, but the back-analysis method yielded equal interface friction angles acting on all three devices, indicating internal consistency. The interface friction angle also matched shear box test results. These outcomes confirm the correct operation of the device in drained seabed conditions, and yield useful information on the sliding resistance of pipes and chains. In addition, the back-analysis method allows measurements from one shape of tool to be used to estimate the response of other objects.     

应用实时定量PCR技术检测秦皇岛近岸海域褐潮原因种——抑食金球藻(Aureococcus anophagefferens)

Aureococcus anophagefferens, a small pelagophyte algae, has caused brown tide blooms in coastal waters of Qinhuangdao in recent years, presenting significant negative impacts on the shellfish mariculture industry. Under standard light microscopy, it is visually indistinguishable from other small algae in field samples due to its extremely small size. In this study, quantitative polymerase chain reaction(q PCR) based on 18 S r DNA sequences was developed and used to detect and enumerate A. anophagefferens. A linear regression(R2 = 0.91) was generated based on cycle thresholds value(Ct) versus known concentrations of A. anophagefferens. Twenty-two field samples collected in coastal waters of Qinhuangdao were subjected to DNA extraction and then analyzed using q PCR. Results showed that A. anophagefferens had a wide distribution in coastal waters along Qinhuangdao. Elevated A. anophagefferens abundance, category 3 brown tide blooms(200 000 cells/m L) occurred at Dongshan Beach and Tiger-stone Beach in August in 2013. In shellfish mariculture areas along coastal waters of Qinhuangdao, 4 stations had category 3 blooms, and 6 stations had category 2 blooms(35 000–200 000 cells/m L) in August and all stations had category 1 blooms(0 to ≤35 000 cells/m L) in October. Quantitative PCR allows for detection of A. anophagefferens cells at low levels in filed samples, which is essential to effective management and prediction of brown tide blooms.     

Precious corals become more precious in the northwestern pacific: Urgent need for integrated policy

The limited precious coral (Coralliidae) resources in the Northwestern Pacific have been managed by Taiwan with a comprehensive management plan, by Japan with a strengthened set of management measures, and by China through the listing of such coral as a Category I national treasures. However, continuous increases in coral consumption and coral prices have stimulated overexploitation and poaching of the resource, and hence have undermined the effectiveness of these management schemes. This article discusses the current precious corals supply chain and suggests that the rise of China in purchasing substantial amounts of coral products was the underlying cause for overexploitation and poaching. Several gaps in the management schemes are also identified and discussed. The article finally concludes that there is an urgent need for establishing a cross-disciplinary integrated conservation policy and a regional management platform consisting of the three participating states to address all the relevant social and ecological issues.     

基于细观力学的混凝土劈拉破坏率相关特性研究

提出了一种高效的混凝土细观力学预处理方法,其中包括基于背景网格的骨料投放与细观三组分的识别;建立了颗粒离散元的混凝土细观力学模型。利用该模型对不同应变率下混凝土的劈拉试验进行了数值仿真,仿真结果显示出的混凝土动力强度提高的规律以及不同应变率下混凝土的破坏模式与试验结果吻合较好。研究表明,随着应变率的提高,混凝土破坏时产生更多弥散状分布的裂纹,同时有些裂纹穿过强度较高的骨料,导致混凝土在高应变率破坏过程中消耗更多的能量,是混凝土的动力强度提高的重要原因。此外,在高应变率下,力链产生更多的分叉,空间分布的不均匀性和随机性增加,因此,在高应变率下混凝土动力强度表现出更大的离散性。     

粤港澳大湾区港口供应链优化研究

为充分发挥粤港澳大湾区港口的竞争优势,促进港口经济的协调发展,文章基于粤港澳大湾区主要港口的实际情况,构建供应链博弈模型并进行数值仿真,研究相关因素对深圳港和香港港绩效的影响。研究结果表明:随着商品价格和库存成本的提高,货物从深圳港向香港港转移,但转移幅度逐渐趋缓;深圳港在中低端商品的货源收集方面具有明显的竞争优势,而香港港对高端商品的吸引力更强;货运结构逐渐向中高端商品过渡对于提高港口收益具有促进作用,其中深圳港应通过降低商品库存成本而降低经营风险;深中通道和港珠澳大桥通车有效缩短腹地运输时间,对于绝大部分商品价格和库存成本组合都将提高粤港澳大湾区港口的总收益。     

纽约时尚产业的空间组织演化及其动力机制

时尚产业作为后工业时代城市发展的新方向而备受瞩目。纽约是公认的全球时尚之都之一,在多方力量的共同推动下,从最初的"血汗工厂"发展至今,其中的经验值得借鉴和学习。产业的发展伴随其空间组织的演化,最终影响城市结构形态。本文对纽约时尚产业经历的四个发展阶段:成衣兴起阶段、产业集聚阶段、设计显露阶段、时尚进化阶段的产业形态和空间组织进行了归纳,并从政府、行业协会、企业和个人四个行为主体出发,探讨了这一过程的动力机制。最后还对中国城市的时尚产业发展提供了政策建议。     

利用温度链对南海内波振幅的观测

内波的实测资料一般为走航或者浮标布站观测得到的一个关于时间和空间的大面资料,将此资料进行滤波后,进行简单的数值处理,即可得到内波的振幅。但是这种资料较少,布控站位难度较大,成本也较高,是一种不易获取的资料。本文利用的温度链资料是一种获取简单,成本也较低的实测资料。利用温度链资料基于内波带动水质点上下波动的物理过程,进行内波振幅的计算,将会有较大的适用性。