山地荒漠草原不同植物群落关系研究

在群落样方调查的基础上，计算群落物种重要值，确定群落类型。对群落物种重要值采用分割线段模型、对数级数分布、对数正态分布、几何级数分布等4个多度模型进行拟合。结果表明，新疆银穗草一细果苔草群落对数级数拟合结果更好，穗状寒生羊茅一细果苔草群落对数正态分布拟合更好，说明了2个群落结构是对2个样地环境特点与放牧干扰相互作用的响应。新疆银穗草一穗状寒生羊茅群落中新疆银穗草处于极优势地位，占据整个群落的大多数生态空间。拟合检验表明，该山地草地植被物种分布格局较符合随机生态位假说和生态位占领假说，严重的放牧干扰不仅降低了优势物种在群落中的优势程度，使次优势物种及其它物种也没能较好的发育，说明外部非生物环境对群落胁迫程度较大。     

基于加速度限控制策略的振动试验过载停机实验研究

西门子Simcenter Testlab振动控制采集分析系统在航天振动试验领域应用十分广泛,但是在实际工程应用中常常由于对软件工作机制理解不到位,参数设置不合理造成试验异常中断,这不仅给产品带来了巨大的安全隐患,而且也增加了试验时间和成本,严重影响研制进度。因此,本文针对某航天产品正弦振动试验的过载停机故障,从软件加速度限控制功能的角度分析了潜在原因,并且开展了实验验证。首先描述了振动试验过程和过载停机现象,排除了硬件原因,然后对可能的加速度限控制功能设置和通道量程过小等原因设计了三组实验进行分析验证,得出了此次试验过载停机①与加速度限控制(频域)设置无关,②而与通道量程(时域)设置有关,③通过忽略限幅通道过载设置可使试验正常进行的分析结论,最后针对Simcenter Testlab加速度限控制功能和通道量程设置提出了使用建议,为后续航天产品振动试验提供参考。     

冲击标准波形及容差问题

本文分析了IEC,MIL—STD—810C中冲击试验方法中冲击波形及容差,并提出了自己的看法。     

弹上火工品可靠性评估方法分析

准确评估弹上火工品可靠度,对掌握弹上火工品可靠性水平和全弹可靠性评估起着至关重要的作用。本文根据弹上火工品试验数据特点,将可靠性评估方法归纳为成败型和连续型。针对成败型数据特点,研究了基于大样本量的二项分布法和基于小子样的最大熵试验法。针对连续型数据的特点,研究了应力—强度干涉模型中单一参数服从正态分布且其他参数为定值的计量法,双参数服从正态分布的应力—强度干涉模型及基于基准设计许用值和可靠性的安全系数法。通过分析上述方法的特点,介绍了可靠性评估方法的应用范围。     

实测振动数据处理与振动加速试验

通过例举一组实测振动数据,并对其进行分析、处理和归纳。介绍了将实测振动数据处理成所需振动谱时的加速振动试验的技术要点和技术方法。     

某机载雷达多自由度振动试验控制方法比较

根据机载雷达实测振动数据,在三轴振动台上,采用不同振动控制方法,对机载雷达单元进行了多自由度振动试验。比较了雷达单元在不同振动控制方法下的安装点响应与参考谱的偏差。试验结果表明:相比于方阵控制,长方阵控制中的坐标变换控制(Input/Output控制)方法在进行多自由度振动试验时,可实现真正意义上的平均控制,振动的传递更为均匀。     

北京市区大气真菌粒度分布及降雨的影响

用ＡＮＤＥＲＳＥＮ生物粒子采样器在北京市西单观测了大气真菌粒子的粒度分布及降雨的影响，结果表明，北京市区大气真菌粒度呈对数正态分布，降雨可明显降低＞６．０μｍ的大气真菌粒子的粒数百分比。     

包装运输件振动试验的夹具设计要求与应用

振动试验是验证包装运输件产品环境适应性的关键环节,振动夹具的动特性直接影响振动试验结果的可靠性.本文阐述了两种不同类型的包装运输件振动试验对振动夹具设计的要求,研制了一种应用于包装运输件振动试验的固定夹具,解决了现有包装运输件夹持固定装置牢固性差、较高包装件易摇摆等问题.     

振动环境试验控制允差的剪裁应用

从工程应用的角度,本文分析讨论了GJB 150.16A对振动环境试验控制允差的要求。结果表明,GJB150.16A对控制允差的要求是灵活的,但是未规定RMS允差,容易造成过试验或欠试验,且对加速度谱密度的控制允差要求的表述存在着一定的模糊。文中给出了解决建议。     

某机载雷达多自由度振动参考谱制定研究

本文阐述了一种基于实测振动数据的机载雷达多自由度振动参考谱制定方法。采用坐标变换法,在时域内从结构的加速度响应中提取出结构的刚体自由度振动。通过对结构刚体自由度振动的信号分析,得到各自由度的自功率谱密度(PSD)和各自由度之间的相干函数γ2(f)和相位θ(f),形成多自由度振动试验参考谱矩阵。用此参考谱进行多轴振动环境试验,可真实地模拟机载雷达的实际振动环境。     

The Normative Limits of Consumer Citizenship

In political philosophy, citizenship is a key concept. Citizenship is tied to rights and duties, as well as to concepts of social justice. Recently, the debate on citizenship has developed a new direction in focusing on qualified notions of citizenship. In this contribution, I shall defend three claims. Firstly, consumer citizenship fits into the discussion of qualified notions of citizenship. Secondly, the debate on qualified notions of citizenship cannot be detached from the normative claims in the philosophy of citizenship more generally. In particular, duties and rights receive a distinct shape when debated in terms of “consumer citizenship”. Thirdly, I shall argue that further normative limits can be established by discussing qualified notions of citizenship as items of a list that need to cohere in normative terms. I shall pay particular attention to environmental citizenship.     

如何确定高加速寿命试验的应力极限

气锤驱动的高加速寿命试验,主要目的是确定试验样品的应力极限(包括工作极限和破坏极限),并通过改进试验所暴露的缺陷,按预期目标拓宽产品的应力极限。本文对一些应力极限的名词术语作了解释性说明,并具体论述了如何确定应力极限及快速温变循环试验的高低温温度极值。     

Limits of Insecticide Cockroach Control in Council Flats in France

The aim of our study was to analyse the results of controlled series of professional insecticide treatments on feral cockroach populations in council flats in three similar multi-family buildings, and to try to understand why control success could be so low. Cockroach abundance and six general environmental characteristics were recorded after each treatment for each flat treated. Cockroach abundance was divided into five levels. The environmental characteristics recorded for each flat were: nationality of residents, duration of occupation, number of residents/m², application of domestic pesticides, reactions of residents to the presence of cockroaches, and degree of cleanliness. This series of treatments, proposed every two months, did not improve the situation as greatly as expected. The presence or the absence of cockroaches in flats can be explained at least partly by some environmental factors like human density in the flat, building effect and cleanliness, but no single factor explains the size of the cockroach population. The usual reasons evoked to explain pest control failures, such as cockroach insecticide resistance, inefficiency of treatments due to formulation, proportion of constituent in compound, periodicity of application, etc., all influence the result of a treatment, of course, but our data show that the part played by the residents in a given dwelling has been greatly underestimated so far. When the results of treatments were analysed, the results depended largely on the residents» attitude.     

Recovery processes in lotic ecosystems: Limits of successional theory

The concept of succession has a distinguished history in general ecology and has been applied to stream ecosystems with some success. Succession in streams is largely secondary, follows initial floristics models, and occurs through a variety of mechanisms. The process is moderately predictable but is highly influenced by “climatic” factors, particularly nutrient chemistry. In desert streams, succession does not result in a climax state. While evidence is slim, succession may not be a significant process in streams of certain types or in certain regions. Successional theory is difficult to apply in spatially heterogeneous, hierarchically organized ecosystems. It also suffers in being only one component of a better integrated concept, that of ecosystem stability, which deals more directly with disturbance and ecosystem resistance in addition to resilience (which encompasses succession). Succession has so suffered from a half century of confusion that a strong case can be made for abandoning the term, at least as it applies in streams, in favor of the broader view provided by stability theory.     

二氧化硫公众短期接触限值探讨

针对二氧化硫接触限值,分析我国目前存在的接触种类和具体标准,并对比国外已颁布的接触标准,说明各标准对公众短期接触不适用的原因,探讨在各浓度下二氧化硫对人体的医学影响程度。文章试图在二氧化硫职业接触限值和环境空气质量标准之间架起桥梁,解决企业对于公众短期二氧化硫接触限值的需求,在结合我国国情并参考主要国家相关标准后得出公众二氧化硫短期接触限值为24h、1mg/m3,8h、2mg/m3的结论。     

Toward Active Community Environmental Policing: Potentials and Limits of a Catalytic Model

This paper offers a field tested community environmental policing model to address the pressing environmental management challenges of reducing e-waste burning in informal e-waste hubs, and enforcement against informal polluting industries more broadly. This is based on our intervention to reduce e-waste burning in a substantial informal e-waste hub in the West Bank, Palestine, a 45 km2 region in which an estimated 5–10 metric tonnes of cables are burnt daily, causing serious environmental and public health consequences. In analogous e-waste hubs in the global South, environmental management solutions have focused on economically attractive alternatives to replace cable burning or policies that integrate informal recyclers with formal e-waste management systems—achieving little success. Our paper describes a two-pronged intervention in Palestine’s e-waste hub, which reduced e-waste burning by 80% through a combination of economically competitive cable grinding services and an “active” community environmental policing initiative that lowered barriers to and successfully advocated for governmental policing of e-waste burning. Our discussion of this intervention addresses the community environmental policing literature, which has documented few successes stories of real improvements to the enforcement of environmental violations. We argue that existing strategies have relied on “passive” approaches comprised of monitoring and reporting environmental violations to advocate for change. Our strategy offers a template to improve outcomes through a more “active” approach, moving from monitoring environmental violations through understanding the rationale and dynamics of violators, identifying environmental policing barriers, and implementing a feasible and persuasive strategy to overcome them.     

Criminalization of “galamsey” and livelihoods in Ghana: Limits and consequences

The fact that the artisanal and small-scale mining (ASM) sector in Ghana is driven largely by poverty means that the sector is a major source of livelihood for people in mining communities across the country. However, given the various social and environmental problems associated with the ASM sector, there is now an emerging consensus that the formalization of the sector would not only allow for these associated problems to be addressed but also ensures that the sector contributes to sustainable development and safeguard the livelihood of local communities. While a large body of extant literature has examined the challenges and opportunities facing the process of formalization, the question of the criminalization of the sector and its consequences for local livelihood has received only limited attention. Drawing from primary data collected during fieldwork in Ghana, this study examined the livelihood implications of the ban on galamsey in the Tarkwa-Nsuaem Municipality in South-Western Ghana from the perspectives of local communities and other key stakeholders. The study reveals that the ban on galamsey has imposed significant socio-economic hardships on the people and appears to be entrenching poverty rather than sustainable development. The study considers the theoretical and practical implications of the findings for sustainable livelihood enhancement in developing countries.     

The biosphere and the threat of global industrialization: Limits of the biosphere

Summary Analysing the influences on the biosphere, this paper emphasises the increasing impact of Man and industrialization. A range of current man-biosphere reactions are described. It is suggested that the effective control and management of the manifestations which result rest, in most instances, with socio-political, socio-economic and socio-cultural factors.Professor M. Kassas is Emeritus Professor of Botany at the University of Cairo and an Advisory Board member toThe Environmentalist. This paper was presented to the Hanover Conference of the Club of Rome in June, 1989.     

Confronting the challenge of greenline parks: Limits of the traditional administrative approach

The National Park Service, like other natural resource management agencies, has adopted the traditional model of public administration, which emphasizes efficiency, effectiveness, economy, and dichotomy between politics and administration. This approach is particularly ineffective in greenline parks and increasingly inappropriate in traditional areas. In an era of ecological interdependence, relationships with other agencies and jurisdictions and with adjacent as well as noncontiguous landowners are as important as controlling visitors. Recreation managers need to develop more skill in negotiation, cooperation, coordination, and interpersonal communication if they are to preserve and protect park resources.