军用飞机自保护系统

本文介绍了飞机自保护系统的组成、发展及应用,指出了飞机自保护系统的发展趋势。

自保护相依多部件系统的预防维修建模及策略优化

自保护技术作为自愈技术的一种,能够使系统在环境或工况条件变化的干扰下以较高可靠性运行。本文构建了一个新的具有相依主要部件和辅助部件的系统可靠性模型,其中主要部件的退化速率与工作中的辅助部件的数量有关。此外,基于定期检测和预防维修策略,本文利用半再生过程技术求解了系统的长期运行平均成本,并以长期运行平均成本最小化为目标给出了系统的最优预防维修策略。最后,以镗刀系统为例,利用所提方法给出了预防更换阈值和检测周期的最优值,以期望为实际维修行为决策提供理论参考。

Effects of Crude Oil Contamination on Soil Physical and Chemical Properties in Momoge Wetland of China

Large oilfields are often coincidentally located in major river deltas and wetlands,and potentially damage the structure,function and ecosystem service values of wetlands during oil exploration.In the present study,the effects of crude oil contamination during oil exploration on soil physical and chemical properties were investigated in marshes of the Momoge National Nature Reserve in Jilin Province,China.The concentrations of total petroleum hydrocarbons in the marsh soil near the oil wells are significantly higher than those in the adjacent control marsh.Soil water contents in oil-contaminated marshes are negatively correlated with soil temperature and are significantly lower than those in the control area,especially in fall.Crude oil contamination significantly increases the soil pH up to8.0,and reduces available phosphorus concentrations in the soil.The concentrations of total organic carbon are significantly different among sampling sites.Therefore,crude oil contamination could potentially alkalinize marsh soils,adversely affect soil fertility and physical properties,and cause deterioration of the marshes in the Momoge National Nature Reserve.Phyto-remediation by planting Calamagrostis angustifolia has the potential to simultaneously restore and remediate the petroleum hydrocarbon-contaminated wetlands.Crude oil contamination affects the soil physical and chemical properties,so developing an effective restoration program in the Momoge wetland is neccesary.

Mapping and Assessing Typhoon-induced Forest Disturbance in Changbai Mountain National Nature Reserve Using Time Series Landsat Imagery

Monitoring forest disturbances is important for understanding changes in ecosystems. The 1986 Typhoon Vera was a serious disturbance that severely impacted the forest ecosystems of Changbai Mountain National Nature Reserve. Although the typhoon disturbance occurred more than two decades ago, the effects of the typhoon still remain within the study area. Few studies have focused on mapping and assessing disturbances across broad spatial and temporal scales. For this study, we first generated a map of forest composition prior to the typhoon disturbance, which served as a baseline data for the extraction of disturbed area. Then, the Disturbance Index(DI) method was tested for mapping the extent and magnitude of disturbance in the study area by applying a Tasseled Cap transformation to the Landsat imagery. The Landsatbased DI method estimated that an area of 13,764.78 ha of forest was disturbed by the typhoon. Based on visual assessments, these results correspond closely with the reference map derived from ground surveys. These results also revealed the influence of local topographic features on the distribution of windthrow areas. Windthrow areas were more pronounced inareas with elevations ranging from 1,000 to 2,000 m, slopes of less than 10 degrees, and southwestern to northwestern aspects. In addition, the relatively long(25 years) post-typhoon recovery period assessed by this study provided a more comprehensive analysis of the dynamics of forest recovery processes over time. Windthrow areas did not recover immediately after the typhoon, likely due to forest management practices enacted at the time. So far, forest recovery has proceeded more rapidly at elevations below 1,400 m, particularly on western slopes within the study area. Finally, a time series of DI values within the study period suggests a secondary disturbance may have occurred between 2000 and 2001.

Practice and Research Progress on Ecosystem Conservation in Transboundary Areas

Many ecosystems extend across national or political boundaries. The consistent and effective protection of these ecosystems in transboundary areas(ETAs) is an important global research focus. Previous research on the protection of such areas can be categorized into seven themes: 1) ecological conservation of a single ETA; 2) investigation of the effects of a single conservation measure on a specific ETA; 3) determination of species-level effects due to ETA conservation; 4) comparison of the same protection measures between different ETAs; 5) introduction of a single conservation measure to a specific ETA; 6) understanding the relationship between conservation and sustainable development; and 7) generalization across multiple ETA conservation cases. The protection of ETAs involves various considerations, including funding support, demand and will for collaboration, community and public participation, historical and cultural factors, political backgrounds, uniqueness of biological resources, formulation of laws and regulations, founding of specialized administrative departments, non-governmental organizations, and fairness. Here, we briefly explain the research themes and considerations related to ETA conservation. The most important finding is that most major research themes do not focus on the challenges of ETA conservation. We use two nature reserves located between China and North Korea as examples to identify specific ways to improve ETA conservation on Changbai Mountains. The efficiency of ETA administration still remains low. The study of ETA conservation should focus on concrete regional information and aim to improve existing measures through the accumulation of experience.

Using the endocannabinoid system as a neuroprotective strategy in perinatal hypoxic-ischemic brain injury

One of the most important causes of brain injury in the neonatal period is a perinatal hypoxicischemic event.This devastating condition can lead to long-term neurological deficits or even death.After hypoxic-ischemic brain injury,a variety of specific cellular mechanisms are set in motion,triggering cell damage and finally producing cell death.Effective therapeutic treatments against this phenomenon are still unavailable because of complex molecular mechanisms underlying hypoxic-ischemic brain injury.After a thorough understanding of the mechanism underlying neural plasticity following hypoxic-ischemic brain injury,various neuroprotective therapies have been developed for alleviating brain injury and improving long-term outcomes.Among them,the endocannabinoid system emerges as a natural system of neuroprotection.The endocannabinoid system modulates a wide range of physiological processes in mammals and has demonstrated neuroprotective effects in different paradigms of acute brain injury,acting as a natural neuroprotectant.The aim of this review is to study the use of different therapies to induce long-term therapeutic effects after hypoxic-ischemic brain injury,and analyze the important role of the endocannabinoid system as a new neuroprotective strategy against perinatal hypoxic-ischemic brain injury.

The Development of a Geographic Information System(GIS) Database for Jiuzhaigou National Nature Reserve and Its Application

The objective of this paper is to develop a GIS(Geographic Information System) database for Jiuzhaigou National Nature Reserve(Jiuzhaigou,hereafter) in China and demonstrate its application as a research tool.A cost-effective procedure was developed to compile a variety of geographical and biological data of the study area in terms of popular GIS format such as shape files.These files were further calibrated and validated using field surveys data.The developed GIS database was used to quantify the distributions of the wildlife(amphibians,mammals,and birds) using the distances of the wildlife to the centerline of the bus-tour routes.The Pearson correlation coefficient was used to quantify the correlation in space between pairs of different wildlife using the number of habitats for given space contexts.An ArcObject-based macro was developed to perform the analysis.The results showed the majority of the habitats of wildlife are located in the proximity of the tour-bus routes with an average distance ranging from 564 to 894 m depending on types of wildlife.This indicates a possibility of the disturbance to the wildlife by human activities.The correlation coefficient of the wildlife ranged from 0.36 to 0.64 depending on pairs of wildlife,indicating some correlations in space.However,due to the limited sample size,the statistical significances need to be further investigated.This paper has successfully demonstrated the use of the GIS-based database as a research tool for environmental study.

Protected Areas, Subsistence Farming Systems and Nature Conservation

The preservation of the traditional subsistence farming systems and the conservation of natural values （habitats, fauna and flora）, in articulation with local development, was the key issues in this paper. The farmers have been able to manage the systems so as to cope with adverse conditions, but their future is quite uncertain. The methodology included： （1） field observation visits and cartographic information analysis of land use; （2） structured interviews with animal production and agro-forestry specialists; and （3） meetings with the participation of stakeholders. The paper concludes that depopulation is responsible for the increasing decline of agriculture and livestock. The decrease in agricultural activity in general and the consequent practices and traditional systems of agriculture causes changes in the landscape and has negative effects on nature conservation and biodiversity. Thus, we believe that the preservation and development of traditional economic activities linked to agriculture, agro-forestry and food processing are essential to maintain the typical landscape and to preserve natural values of Montemuro Site. The paper shows that in mountain areas, particularly those classified as nature network sites, farming, economic development and nature conservation are not antagonistic objectives.

Heat resistance and water protection effectiveness for large single-pane fireproof glass

The effects and heat transfer mode of water film and sprinkler system on the heat-resistant property associated with the insulation of a fireproof glass were investigated. In the experiments, fireproof glass with a size of 3 300 mm （height）×2 200 mm （width） ×12 mm （thickness） was exposed to an oil pool fire with a power of approximately 1.4 MW. The experimental results show that the application of the water film or sprinkler system on the glass can effectively resist the intensive heat from the fire in the test due to the absorption of latent heat. The permitted period of integrity and insulation with a water film and a sprinkler system could be extended to 60 min. It should be noted that the temperature of the glass surface Can be kept under 60℃in a 60 min test. The experimental results suggest that it is feasible to substitute fireproof glass with water film for a fireproof door as long as the water film or sprinkler system can work stably and water can cover the whole surface of the frreproof glass.

Predicting Potential Distribution of Gaur （Bos gaurus） in Tadoba-Andhari Tiger Reserve, Central India

The rapid pace of development of GIS （geographical information system） has assisted in identification of conservation priority sites by delineating species distribution using models on habitat suitability. Gaur, Bos gaurus, is categorized as ＂Vulnerable＂ in the IUCN Red List of Threatened Species, 2009. The study has used ENFA （ecological niche factor analysis） to understand the distribution status of Gaur in TATR （Tadoba-Andhari Tiger Reserve）, Central India. TATR was sampled using stratified random sampling strategy. A total of 21 continuous variables were used, categorised under 4 environmental descriptors categories viz. habitat, anthropogenic, topographic and hydrological variables. All the variables were tested for the correlation and one of the variable among strongly correlated （r 〉 0.7） variables was discarded to avoid redundancy. A total of 14 variables were retained. The model resulted in marginality of 0.56 and specialization of 2.608. Presence of Gaur showed the positive association with canopy density classes （〈 30% ＆ 40-60%） and open forest. However, it was negatively associated with elevation, non-forest, riparian forest, scrub and teak forest. The study has delineated the areas where appropriate habitat conditions exist to sustain Gaur populations vital for planning strategies for conservation of this megaherbivore species in tropical forests.

Emergy Evaluation of a Village Ecosystem in Wolong Nature Reserve in China

Due to historic reasons, there are several human settlements in nature reserves and national parks, which may constitute a threat to biodiversity. Establishment of nature reserves may however generate constraints for development of local communities residing in these reserves. The village ecosystem of Zhuanjinglou Village in Wolong Nature Reserve includes population, farming and livestock (domestic and alpine) and forest ecosystem. An emergy analysis of agro-ecosystem (including the farming and livestock ecosystem) and energy consumption in Zhuanjinglou Village indicates that livestock ecosystem plays an important role in village ecosystem, which may be the source of great pressure on the state of the local environment. The increasing ratio of electricity in energy consumption may play a positive role for environmental conservation. Despite some successful experiences, there are some remaining issues that need to be addressed in the ecological rehabilitation of the village ecosystem.

Climate Change Adaptation for People and Nature:A Case Study from the U.S.Southwest

In the U.S.Southwest,global climate change,acting in concert with extant stressors such as urbanization and over-allocation of water resources,is changing ecosystems in measureable and sometimes dramatic ways.Twenty-first century projections indicate accelerating climate change and cascading ecological consequences.Effects observed to date include large-scale forest dieback,large and severe wildfires,and changes in the flow regimes of rivers and streams with attendant changes to riparian and aquatic ecosystems.Rising temperatures and changing precipitation patterns are pushing ecosystems across physiological and ecological thresholds,causing widespread mortality and,in some cases,major changes in composition,structure and function.These changes have prompted action by the conservation community to reduce the adverse effects of climate change.The Southwest Climate Change Initiative(SWCCI),a project led by The Nature Conservancy,works with local stakeholders in affected landscapes,reduces adverse impacts on ecological and social systems using scientific knowledge and practical tools.The Initiative has learned through practical experience that: 1) managers must embrace change and manage for resilience rather than resistance;2) strong local science-management partnerships are critical to effective adaptation planning and implementation;3) planners and managers must broaden the scope and accelerate the pace of conservation activities if ecosystem services are to be sustained;4) adaptation often does not require radically new or different management practices,rather,conservationists already have many of the tools they need;and 5) rapid documentation and widespread communication of methods and findings can build rapidly regional capacity for climate change adaptation.Our experience suggests that adaptation efforts can be effective if they are focused at the local scale;employ learning networks;and engage in ecosystem-based adaptation:the sustainable management,conservation and restoration of ecosystems so that they continue to provide the services that allow people to thrive in changing environments.

Ecology, Biology and Biometry of an Endemic Fabaceae： Genista Saharae Cosson and Durieu

Genista saharae Cosson and Durieu, endemic Saharan Africa, is a spontaneous fabaceae dunes south of M＇sila （Algeria）. Perfectly adapted to arid and sandy soils, this species is a remarkable plant for dune fixation and thus fights against desertification. The objective of this study is to provide local species to various development programs of steppe ecological systems in nature and therefore ensure the rehabilitation of these species while considering the conservation of biodiversity and sustainable management of biological resources steppe. After a field survey and stratified sampling, the methodological approach has taken into account three types of analysis： a biometric analysis of a population of 100 individuals of this species, the second analysis on its biology at last an analysis of an ecological factor dealing with the accuracy governing the distribution of this species in Maiter Oued in the south of M＇sila. The results have clarified the ecology of this species to better understand its biology and to develop statistically a diagnosis on the phenology and morphology of various organs （pods, seeds, leaves） of Genista saharae Cosson and Durieu.

New Framework for Evaluating Ecosystem Quality in Nature Reserves based on Ideal References and Key Indicators

With increasing numbers and types of nature reserves(NRs),objective evaluation and comparison of the effects of different nature NRs on conservation efforts are of great importance for protecting species diversity,ensuring reasonable national economic input,and adjusting government management schemes.Developing a method for the combined assessment of flagship or umbrella species and ecosystem quality will improve the evaluation of NRs.However,it is also important to establish a new framework for rapid evaluation of ecosystem quality,supported by the advantages of scientific,economic,and regular principles.Here,we proposed a new framework that incorporates the novel concept of ideal references into evaluation systems,which will facilitate the comparison of results from different periods and regions.Furthermore,from the perspective of making the framework as objective,rapid,and economical as possible,we recommended some key ecological indicators,such as net primary productivity,soil organic matter,plant diversity,for use in the new evaluation framework.The new framework,referred to as“ideal reference and key indicators”(IRKI),can sufficiently meet the requirements for the rapid evaluation of ecosystem quality both regionally and nationally.Furthermore,IRKI can identify the restoration potential and restoration periods of NRs,thus facilitating the rational distribution of resources and enhancing the protective effect.There are many types of NRs in China,and it is necessary to partially alter the assessment methods or parameters for different types of NRs.Overall,IRKI provides a simple,clear,and comparable framework that will strongly enhance the conservation of protected areas(PAs)and facilitate the standardization of management practices.