基于多孔介质模型的土壤风蚀风洞湍流涡发生器设计的数值模拟

该文针对土壤风蚀风洞中设计湍流涡发生器模拟大气边界层的需要,利用计算流体动力学（CFD）软件Fluent对NK-1可移动式风蚀风洞中典型农田风蚀地表风速廓线进行数值模拟,提出引入多孔介质模型的方法将原非规则几何结构的棒栅进行替代计算,最终得到棒栅加粗糙元的最优分布,并通过室内风洞试验进行验证。结果显示,风洞试验实测与模拟所得廓线的相关系数为0.974,模拟效果较理想。该方法使得计算网格数量减少,网格质量提高,节约了模拟成本,提高了计算的精确度和可信度,并且验证了用棒栅-粗糙元组合作为湍流涡发生器来模拟复现大气边界层是可行的,以期为风洞湍流涡发生装置的设计模拟提供一种新的思路和方法。     

Choosing the survivors? A GIS-based triage support tool for micro-endemics: Application to data for Mexican amphibians

Given the current speed of land use change, we cannot expect to save all species from extinction, and so must decide how to focus limited resources to prevent the greatest number of extinctions. This paper proposes a simple conservation triage method that: evaluates the threat status for 145 micro-endemic Mexican amphibian species; assesses current potential threat abatement responses derived from existing policy instruments and social initiatives; and combines both indicators to provide broad-scale conservation strategies that would best suit amphibian micro-endemic buffered areas (AMBAs) in Mexico. To prioritize the AMBAs we used existing and newly compiled spatial databases of territorial conservation instruments, threats, and amphibian range distributions for Mexico. We identify 50% of Mexican micro-endemic amphibians as requiring urgent actions. Based on the location of the AMBAs and using existing conservation instruments, we develop a conservation strategy for the majority of these species. However, almost 25% urgently need field-base verification to confirm their persistence due to the small percentage of remnant natural vegetation within the AMBAs, before we may sensibly recommend such a strategy.     

Hazard,risk and agrarian adaptations in a hyperarid watershed: El Niño floods,streambank erosion,and the cultural bounds of vulnerability in the Andean Middle Horizon

Peru's Osmore drainage, also known as the Moquegua Valley, is one of the driest regions on Earth, yet agricultural development has supported complex societies in the basin for almost 4000 yrs because of canal construction and irrigation. We compare the distinct agrarian and settlement systems of three coeval archaeological cultures in this arid region, Huaracane, Wari and Tiwanaku, and how each adapted—or failed to adapt—to geomorphic and climatic hazards. Systematic settlement pattern survey and radiocarbon dating along with geomorphological analysis of flood history and riverine processes permit detailed discussion of agrarian strategies during the Formative (1800 BC–AD 500) and Middle Horizon (AD 500–1000) periods, with distinct settlement “niches” in terms of agricultural practices and longitudinal position in the drainage, and lateral location relative to the floodplain. These adaptive strategies each manifest distinct “bounds of adaptability” to natural hazard, climate events and social stressors, and thus varying risk profiles. Besides the continual risk associated with sustained droughts, the Atacama and Peruvian Coastal Desert and culturally connected highland Altiplano are also vulnerable to the vagaries of the El Niño-Southern Oscillation (ENSO) leading to catastrophic floods in the mid-valley during warm phase ENSOs, in tandem with simultaneous hazards in other regions inhabited by these transregional cultures. By comparing the archaeological record of Wari, Huaracane, and Tiwanaku culture settlements with geomorphic signatures of catastrophic El Niños, we show that the viability of each cultural sequence depended on specific relationships to floodplain streambank erosion, construction and reworking over multiple time scales.     

耕地征用价格构成的理论分析

以耕地功能价值为依据,运用社会成本和私人成本理论,揭示现行耕地征用补偿偏低及其引发的问题,在此基础上提出以耕地功能价值为确定征用价格的理论依据,并给出耕地总价值的量化标准.     

瑞利面波频散曲线的理论计算研究

通过定义一种新的位移应力矢量和势矢量，导出了一种新的传递矩阵，其形式简单明了，而且所有的矩阵元素均为实数值且为无量纲量，这种独到的优点使得本文的方法在数值稳定性上得到了很好的改善，在此基础上本文还对表面位移及短波、长波近似进行了研究，数值计算结果验证了本文方法的有效性，且表明了本文的方法完全适用于平面瑞利面波频散曲线的理论计算，扩宽了本文方法的应用范围。     

Towards a theory of values-based labeling

An outline of a theory ofvalues-based labeling as a social movementargues that it is motivated by the need tore-embed the agro-food economy in the largersocial economy. A review of some basic premisesof embeddedness theories derived from the workof Karl Polanyi reveals their connection toparticular values-based labeling efforts. Fromthis perspective, values-based labelingpresents itself as primarily an ethical andmoral effort to counter unsustainable trendswithin presently existing capitalism. Theselabels distinguish themselves from ordinarycommercial labels by a focus on processand on quality. Evaluating thetransformative potential and progressive natureof values-based labeling poses a key challenge.One avenue for gauging this potential isconventions theory. This approach can beadapted to consider the decision makingprocesses that go on within values-basedlabeling groups, as well as consumer decisionmaking based on such labels, as instances ofwhat is termed a politics of ethical judgment.The conclusion emphasizes the need for moreresearch in this area and suggests how it couldbe furthered.     

不同培养基质和栽培方式对金针菇产量的影响

为了解不同培养基和栽培方式对金针菇产量的影响规律，用木屑，棉子皮为主料，适当搭配甘蔗兴旺等辅料，以生料，煮产和灭菌料，袋栽，夺块栽方式栽培金针菇。结果表明，以配方７８％棉子壳，１０％精米糠，１０％甘蔗渣，１％过磷酸下和１％石膏栽培的菌丝生长速度快，长势好，产量高，品质好，生物效率高达１２８％；在栽培方式上，以灭菌袋栽最好。     

安徽省林业重点工程效益评价

综合运用国内外各种森林效益评价的理论和方法 ,对安徽省林业重点工程项目实施后的森林生态效益、经济效益、社会效益进行了总体评价。结果表明 :重点工程实施后 ,三大效益显著提高 ,其中森林的生态效益和社会效益起主导作用 ,综合效益达到了 70 .97亿元 /年。     

传媒烛照下的人性光芒

本文通过对法兰克福学派和文化研究学派的不同立场分析“人”这一主体看在文化与传媒研究中的历史地位;并尝试提炼现代传媒文化体系在处理人群与传媒关系上的运转模式,解证“传媒学即人学”的基本观点;同时,求证“人”作为文化传媒核心的合理性并寻求其精神文化的归宿。     

防洪系统与社会经济系统和谐预警模型研究

对社会经济系统、防洪系统以及二者之间的相互联系进行了定量研究,构建了防洪系统与社会经济系统和谐预警的系统动力学模型,给出了此模型的一般表达式和预警信号设置,并以抚顺地区为例作实证分析.