毗邻沙漠地区微分博弈模型与宏观环境治理策略研究

工业化发展导致了脆弱的土地进一步沙漠化,沙漠地区政府应综合考虑经济发展与土地沙漠化导致的生态质量降低。通过构建两个沙漠化地区微分博弈模型,研究了两个地区的沙漠治理问题。研究结果表明,提高工业生产排放技术或沙漠治理技术均能够提高均衡经济产出水平,在工业生产收益系数较高的情况下也能够提高沙漠治理投入水平,并且两种技术提高存在交互效应;只有对生产排放技术水平和沙漠治理技术水平较高的地区,延长地方政府领导任期有利于沙漠治理;实现沙漠完全治理情况下控制土地再沙化的治理投入低于控制沙漠稳定在一定规模的治理投入。     

青藏铁路纳赤台地区荒漠典型植物四种常量元素特征

分析了青藏铁路纳赤台段荒漠地区的土壤及10种典型植物的常量元素中的K、Ca、Mg、P四种元素的含量。结果表明,（1）K、ca、Mg、P四种元素在区内各种植物中的变异系数分别为0．033、0．418、0．143、0．403,Ca和Mg元素在各种植物中的含量呈正相关;（2）区内所采集到的各种植物之问K、Mg两种元素含量变化不大;（3）随着土壤深度的增加,土壤内四种矿质元素含量呈递减趋势。     

Characteristics and source of black carbon aerosol over Taklimakan Desert

Black carbon(BC) and PM10 in the center of the Taklimakan Desert were online monitored in the whole year of 2007.In addi-tion,TSP samples were also synchronously daily collected by medium-volume samplers with Whatman41 filters in the spring of 2007.BC in the dust aerosol was up to 1.14%of the total mass of PM10.A remarkable seasonal variation of BC in the aerosol was observed in the order of winter>spring>autumn>summer.The peak value of BC appeared at midnight while the lowest one in the evening each day,w...     

新疆荒漠林下土壤的模糊聚类分析

本文收集了10个新疆荒漠林下土壤样品,每个样品选择6个变量,原始数据经标准化处理后,进行了模糊聚类分析.计算结果,将原分类的林灌草甸土和盐土两个类型,聚类为荒漠灌木林土、棕漠林土、棕漠林盐土、荒漠灌木林盐土四类.结果表明,在测量数据正确、选用土壤样品适当的情况下,模糊聚类分析是研究新疆荒漠林下土壤分类的一种有效方法.     

Humulene derivatives from Saharian Asteriscus graveolens

Three new sesquiterpene-humulenes, (?)- asteriscunolides I (1), J (2) and (?)-(2Z,6E,9Z)-8-oxo-1α-acetoxy-2,6,9-humulatrien-12-oic acid (3) were isolated from the leaves-flowers of the Saharan medicinal plant Asteriscus graveolens along with six known compounds. The structures of the compounds were determined on the basis of spectroscopic mono and bidimensional NMR, mass spectrometry and by single-crystal X-ray diffraction. Compounds 1–3 were evaluated for cytotoxic assay, no significant activity was detected.     

仿生定向液体输送的功能材料表面设计与应用

无外界能量输入及设备辅助的情况下,在基底表面上控制液体自发输送在微流控和流体低能耗运输中具有重要意义。然而,液体的自发输送会被接触角滞后效应及摩擦阻力所阻碍。自然界中的生物(如蝴蝶翅膀、仙人掌、猪笼草、蜘蛛丝和沙漠甲虫)特殊的表面形貌结构能够将收集到的水分自发输送。受此启发,通过表面调控等方法人工合成材料的仿生表界面也可以自发运输液体。近十余年,仿生表面的液体定向输送得到了广泛关注和深入研究,预期在定向集水、宏观液体输送、油水分离、微流控系统等领域具有广泛的应用前景。本综述系统地介绍了定向运输液体功能材料的原理、合成方法及其应用,深入解析了制约其应用的主要因素,并总结和展望了定向运输液体的功能材料在未来发展中所面对的机遇与挑战。     

Assessment technique for evaluating military vehicular impacts to vegetation in the Mojave desert

A new plant-damage assessment technique was developed. The technique consists of linear transects the width of a military vehicle’s tracks located in existing tracks in the soil (usually during a prior training rotation period of 30 days or since the last rain or wind storm). Measurements of vegetation within the tracks are used to determine the area of plant parts impacted. The percent of the plant parts damaged and the percent expected to recover are estimated. The technique documents prior-damage classes based on estimates of damage that plants have apparently experienced previously (as assessed from field indicators of damage such as plant shape and height). The technique was used to evaluate different vehicle types (rubber-tire wheels vs. metal tracks) in six areas at the NTC with different soils and training intensity levels. The technique provides tabular data that can be sorted and queried to show a variety of trends related to military vehicular impacts. It also is suitable for assessing other non-military off-road traffic impacts. The study reports: (1) differences in plant sensitivity to different vehicle track types, (2) plant cover and density by species and training area after prolonged impact, (3) the degree to which rubber tire wheels have less impact than metal tracks, and (4) mean percent survival was inversely proportional to the degree of prior damage received by the vegetation (i.e., plants previously impacted have lower survival than plants not previously impacted).     

Non-destructive estimation of canopy gap fractions and shrub canopy volume of dominant shrub species in the Mojave desert

Variability of desert shrub canopy volume or above ground biomass can provide a useful metric for assessment of the response of desert shrubs to vehicular impacts, and can be used to determine the recovery and resiliency of different desert plant communities to such impacts. Traditional methods for measuring desert shrub canopy volume are inefficient and require destructive sampling. Field sampling methods that eliminate the need for destructive sampling are required to measure the vertical structure of desert shrubs for the purpose of measuring shrub volumes. Plant canopy analyzers and hemispheric photographs have been analyzed for the purpose of estimating canopy characteristics in forested and agricultural environments, but the utility of such instruments for measuring vertical structure of desert shrubs has not been fully explored. In this research, plant canopy gap fractions were estimated for 96 shrubs in the Mojave Desert using both a Li-Cor LAI 2000 Plant Canopy Analyzer and skyward looking hemispheric photographs collected with a digital camera with a fisheye lens attached. Gap fraction estimates from both estimates were comparable and no significant difference was found between estimates collected with both instruments. The LAI was identified as the preferred method for measuring gap fractions due to superior efficiency in data collection and processing. Using gap fractions recorded with the LAI, a model was developed to estimate the volume of desert shrub canopies that utilizes a combination of non-destructive, in situ measurements of plant canopy height and width and estimates of canopy area derived from remotely sensed imagery.     

Soil depth profile of 137Cs, 210Pb and 40K in Algeria

ABSTRACT

Three soil depth profiles of ²¹⁰Pb, ¹³⁷Cs and ⁴⁰K at different areas of Algeria were studied. The soil sampling areas are near the location where the French nuclear tests took place at 1960–1966. The two depth soil profiles were collected at Ghardaia region and the third one at Reggane region. The vertical distributions of radionuclides at the two soil depth profiles from Ghardaia region are different, probably due to the different soil composition. The soil depth profile from sandy soil show uniformity in the distribution of radionuclides without a clear maximum (peak). The soil depth profile that characterised by silty sand show a clear peak at 20–50?cm depth for all studied radioactive nuclides, while the observed activities are two times higher than the corresponding values in sandy soil samples. More specifically in Ghardaia region the ²¹⁰Pb, ¹³⁷Cs, ⁴⁰K activity concentrations ranged between 27 and 50?Bq?kg^?1, 0.2 and 3?Bq?kg^?1 and 75 and 90?Bq?kg^?1 respectively in sandy soil type and between 37 and 75?Bq?kg^?1, 4 and 6?Bq?kg^?1 and 140 and 180?Bq?kg^?1 respectively in silty sand soil type. Finally, the third depth soil profile collected from Reggane site presents a completely different distribution of the studied radionuclides. The activity concentrations of ²¹⁰Pb, ¹³⁷Cs, ⁴⁰K ranged between 37 and 51?Bq?kg^?1, 0.16 and 0.39?Bq?kg^?1 and 120 and 309?Bq?kg^?1 respectively. Three peaks in the ¹³⁷Cs distribution revealed, were most probably, Chernobyl related ¹³⁷Cs accounts for the surface peak, while the deeper peaks are connected to the weapons fallout.     

First field-based observations of δ2H and δ18O values of event-based precipitation,rivers and other water bodies in the Dzungarian Gobi,SW Mongolia

For certain remote areas like Mongolia, field-based precipitation, surface and ground water isotopic data are scarce. So far no such data exist for the Mongolian Gobi desert, which hinders the understanding of isotopic fractionation processes in this extreme, arid region. We collected 26 event-based precipitation samples, 39 Bij river samples, and 75 samples from other water bodies in the Dzungarian Gobi in SW Mongolia over a period of 16 months for hydrogen and oxygen stable isotope analysis. δ²H and δ¹⁸O values in precipitation show high seasonal variation and cover an extreme range: 175?‰ for δ²H and 24?‰ for δ¹⁸O values. The calculated local meteoric water line (LMWL) shows the isotopic characteristics of precipitation in an arid region. Individual water samples fall into one of three groups: within, above or below the 95?% confidence interval of LMWL. Data presented provide a basis for future studies in this region.