为了解三峡水库蓄水后期香溪河库湾浮游甲壳动物群落结构及其时空变化,于2015年1月至2017年12月对香溪河库湾浮游甲壳动物进行了逐月采样分析.共鉴定出浮游甲壳动物23种,其中枝角类10种,桡足类13种.出现频率较高的物种均为长江流域常见种,生物量和密度峰值分别出现在5月和6月,在1月和2月则未能采集到标本,生物量和密度在年际间差异显著,但群落组成差异不显著,群落季节变化规律表现为春季-夏季以蚤状溞(Daphnia pulex)和僧帽溞(Daphnia cucullata)大型枝角类占优势,秋季以简弧象鼻溞(Bosmina coregoni)小型种占优势.库中生物多样性指数高于库首和库尾,库首和库尾生物多样性指数差异不明显,生物多样性在季节上同样具有一定差异.CCA分析表明水温、叶绿素浓度和水深是解释浮游甲壳动物群落变化重要因素.我们的研究结果表明尽管香溪河库湾营养盐、水温、浮游甲壳动物生物量和密度均未达到稳定状态,但群落组成在年际间无显著性差异,浮游甲壳动物物种丰富度也高于蓄水初期,生物多样性指数存在一定的时空差异,适当程度的干扰有利于维持浮游甲壳动物较高的生物多样性.

为了解三峡大坝蓄水完成之后香溪河库湾水体及沉积物中氮、磷的分布状况以及沉积物污染水平,2013年4月对三峡水库香溪河库湾进行调查采样,测定表层水及沉积物中氮磷含量和形态组成.结果表明,香溪河库湾表层水总磷(TP)含量范围为0.20～0.51 mg?L-1,总氮(TN)含量范围为0.54～2.25 mg?L-1,TP主要由磷酸盐(PO3-4)组成,TN主要由硝酸盐(NO-3)以及氨氮(NH+4)组成,TP在空间上呈现从河口向库尾逐渐升高的分布格局,TN分布从河口向库尾逐渐降低.香溪河库湾沉积物中TP含量变化范围为642～1189 mg?kg-1,TN含量变化范围为867～1718 mg?kg-1,沉积物TP含量分布呈现上游高下游低,沉积物TN分布趋势呈现中间高,两头低.沉积物中TP主要由无机磷(IP)组成,有机磷(OP)所占比例较小,其中IP由钙磷(Ca-P)、铁铝磷(Fe/Al-P)组成,三者含量:Ca-P>OP>Fe/Al-P,且沉积物TP含量空间变化受到三者影响(P<0.05).采用单一因子标准指数法对香溪河库湾沉积物中TN、TP污染水平进行评价,结果表明,表层沉积物中TN、TP最低级别污染指数平均值为2.0和1.6,表层沉积物中TN、TP污染指数均超过最低污染水平,且TP的严重级别污染指数达到0.5以上.三峡水库三期蓄水完成以后,香溪河库湾表层水体中氮磷含量较初期蓄水有所升高,各样点沉积物中氮磷含量表现出相同的趋势,沉积物中不稳定磷释放对水体富营养化具有影响,香溪河库湾的表层沉积物已经受到一定的污染,磷污染水平较高.

黄土高原陇东地区有着特殊的气候背景和下垫面,对这一地区陆气相互作用特征和影响因素的观测分析对改进和发展陆面过程模式以及气候变化研究有重要意义.利用陇东平凉陆面过程与灾害天气观测研究站连续一年的陆面过程观测资料,分析了雨养农田降水量、土壤含水量、辐射、反照率和能量通量的季节变化,以及降水、土壤含水量和农业生产活动对能量分配的影响.结果表明,陇东地区降水量季节分布不均,土壤含水量有明显季节差异,随降水有明显波动;辐射通量的季节变化较为规律,短波辐射的日均值受天气状况影响,波动较大;地表反照率呈明显的季节变化,全年正午反照率最大值为0.83,出现在降雪后,生长季随着作物的生长,反照率下降至0.2以下,农作物收割以后的裸土反照率随降水变化明显,反照率与土壤体积含水量呈明显的线性相关关系;湍流能量通量日循环和季节变化明显,地表能量分配在很大程度上受降水影响,同时农业生产活动也对其有较大影响,主导能量通量有较大的月际波动,潜热通量月平均日变化峰值最大为240.8W·m2,出现在5月,感热通量为192.5 W·m-2,出现在4月;在年尺度上,正午净辐射多被感热通量消耗,感热通量约占35％,潜热通量约占32％,低于灌溉农田;在冬小麦快速生长季(3-5月),潜热通量约占34％,远低于灌溉的冬小麦田,研究站点的蒸散发过程受到水分限制.

Understanding the land–atmosphere interactions over the semi-arid area of Loess Plateau is important due to its special climate and unique underlying surface. In this study, two years' micrometeorological and energy flux observations from the Pingliang Land Surface Process & Severe Weather Research Station, CAS were used to investigate the seasonal and interannual variations of radiation budget and energy fluxes over a rain-fed cropland in the semi-arid area of Loess Plateau, with an emphasis on the influence of rain, soil moisture and agricultural production activities (such as crop type and harvest time) on the energy partitioning as well as the surface energy balance. The results revealed large annual variations in the seasonal distribution of precipitation, which gave rise to significant seasonal and interannual variations in soil moisture. Soil moisture was the main factor affecting radiation budget and energy partitioning. There was a negatively linear relationship between the albedo and the soil moisture. The main consumer of available energy varied among months and years with an apparent water stress threshold value of ca. 0.12m3m−3, and the evapotranspiration was suppressed especially during the growing season. On an annual scale, the largest consumer of midday net radiation was sensible heat flux in 2010–2011, while it was latent heat flux in 2011–2012, which accounted for about 35% and 40% of the net radiation, respectively. The agricultural activity altered the sensitivity and variability of albedo to soil moisture, as well as energy partitioning patterns. The surface energy budget closures during Dec. 2010–Nov. 2011 and Dec. 2011–Nov. 2012 were 77.6% and 73.3%, respectively, after considering the soil heat storage. The closure was comparable to other sites in ChinaFLUX (49% to 81% of 8 sites). The patterns of energy partitioning and the water stress threshold found in the semi-arid cropland could be used to evaluate and improve land surface models.

Wind fields over the Loess Plateau are very complex due to the complex underlying surface.This paper investigated the effect of subgrid-scale terrain parameterization on near surface wind fields simulated by the WRF over the Loess Plateau.Results indicated that the subgrid-scale terrain standard deviation (σs o )was larger over complex terrain,and the elevation differences between obser-vation sites and the nearest model grids increased withσs o.In summer of 2012,wind speed in the designated region was small.When the influence of subgrid-scale terrain was ignored,the WRF over-estimated wind speed when the observation value was higher,but under-estimated wind speed when the observation value was smaller.The RMSE between the simulated and observed wind speed was small over relatively flat area,while it was larger over complex terrain area.Simulated wind speed was much closer to observations when subgrid-scale terrain parameterization scheme was included in the WRF.Statistics indicated obvious improvement in the accura-cy of simulated wind speed.Although simulated wind speed was higher than observations,the diurnal variations were well captured by all the simulations and the lowest bias was achieved when Jimenez’s parameterization scheme was used.Simulations with Jimenez’s parameterization scheme could precisely capture the spatial distribution feature of wind speed,but simulations with Mass’s parameter-ization scheme had medium improvements at all stations.

以氧化石墨烯(GO)和钛酸四丁酯(Ti(OBu)4)作为初始反应物,采用乙醇溶剂热法合成了石墨烯/纳米TiO2复合材料,并利用XRD、FE-SEM、TEM、RAMAN和XPS等手段对石墨烯/纳米TiO2复合材料的晶体结构、形貌及元素形态等性质进行了表征,同时将复合材料应用于光催化降解甲基橙溶液,进行光催化性能评价.结果表明:Ti(OBu)4在乙醇溶剂中通过化学静电引力吸附到GO表面,经过溶剂热反应,GO被还原成石墨烯的同时,石墨烯的表面负载生长锐钛矿TiO2颗粒.随着溶剂热反应时间的延长,GO表面的活性基团减少,还原更加彻底,同时TiO2晶粒有一定的增大趋势;与纯TiO2相比,石墨烯/纳米TiO2复合材料光催化活性明显提高,石墨烯含量对复合材料的光催化活性有直接的影响.

利用2010年6月平凉陆面过程与灾害天气观测研究站陆面过程观测资料,对比分析了温度积分法、温度预报校正法和谐波法三种土壤热通量计算方法以及这三种方法的计算结果对地表能量平衡的影响,并探讨了土壤水分运动对土壤热通量的影响.结果表明,研究区土壤垂直非均质性明显,由谐波法计算得到的0.05 ～0.l0m土壤热扩散系数κ是0.10 ～0.20 m土壤层的3倍左右.通过对比三种方法计算得到的0.05 m土壤热通量和热通量板的实测结果表明,温度积分法、温度预报校正法和谐波法计算的土壤热通量峰值都比实测值偏小,分别偏小约23.6％、25.0％和12.8％.与不考虑土壤热存储的情况相比,利用温度积分法和温度预报校正法将土壤热通量板的实测结果校正到地表,这样得到的陇东黄土高原雨后晴天农田地表能量闭合率分别提高了7.96％和4.54％;由谐波法计算的地表土壤热通量可使地表能量闭合率提高约5.65％.在夏季雨后晴天,发生在农田土壤中的水汽输送及相应的相变过程对土壤热通量有一定影响.

WRF is one of the most widely used numerical weather prediction models,for which reanalysis data provide initial and lateral boundary conditions. Different reanalysis products may affect WRF simulation results differently. Taking Loess Plateau as research area,two WRF experiments( NCEP /WRF and ERA /WRF),using surface observation data and sounding data,taking NCEP and ERA-Interim reanalysis as initial and boundary conditions,respectively,were conducted to evaluate the influence of different reanalysis products on WRF simulations. The results indicated that both experiments can accurately reproduce the diurnal variation of 2 m temperature,2 m relative humidity and surface temperature,with ERA /WRF giving better results than NCEP /WRF.Due to the complex terrain in the studied area,model performance for 10 m wind speed was poor. Both experiments cauld approximately simulate the diurnal variation of radiation components and ground heat fluxes. The deviation from observations mainly appeared at noon. Both experiments captured the variation of potential temperature and specific humidity in the atmospheric boundary layer well with correlation coefficient higher than 0. 8.However,the performance for wind speed was not as good,with correlation coefficients of 0. 63 and 0. 60,respectively,for NCEP /WRF and ERA /WRF experiments. NCEP /WRF performed better than ERA /WRF in the atmospheric boundary layer.

Ecological security is an important environmental indemnification and its assessment is a scientific foundation for the sustainable development of a region. A spatial pattern modelling of a regional ecological security had been developed by a few representative indices after considering the ecological security load and ecological security support system capacity in this paper. The paper proposes location coefficient,which is a new method to measure the regional differentiation in ecological environmental aspect. And GDP and population were used to describe the ecological security load produced by the regional human society system. Biomass of forest distribution,which is a new concept,is taken as the capacity of ecological security support system. Taking Changting County of Fujian Province as the example,the regional ecological security was assessed quantitatively for soil erosion. The results showed that the area of ecological security and comparison security in Changting County occupied 87.75% of the total land area. The impacts of regional ecological security by forest resources,regional differentiation and human activities were discussed in this paper,and human activities are the key aspects affecting the regional ecological security.

Well-aligned open-ended multi-walled carbon nanotube (MWCNT) arrays were prepared via chemical vapor deposition (CVD) method in porous anodic aluminum oxide (AAO) templates without depositing any transition metals as catalyst. Effects of the CVD temperature and heat treatment were studied in detail. Well-aligned open-ended MWCNT arrays were obtained at the CVD temperature above 600 C; when CVD temperature is reduced to around 550 C, CNTs, CNFs and other structures existed at the same time; no CNTs or carbon nanofibres (CNFs) could be found as the CVD temperature is below 500 C, and only amorphous carbon in the porous AAO template was found. Experimental results showed that the AAO template is catalytic during the CVD process, and it has the following two effects: to catalyze thermal decomposition of acetylene and to catalyze conversion of carbon decomposed from acetylene into CNTs or CNFs. Heat treatment could improve the graphitization degree, but it might also introduce new defects.

With the deepening of informanization development, the range of computer and internet / intranet application and the scale of the application systems are expending. A common problem that lies ahead of us is how to integrate with and share the information resources that have been built. Taking the project of the e-government information sharing platform of Fujian Provincial Digital Forestry as an example, based on protecting the investment in information, the overall solution scheme and realization methods of the information exchange and sharing are studied by means of MS.NET/ XML Web Services / MS BizTalk Server 2004 core technologies for the sharing information requirement of Fujian Provincial Digital Forestry application systems in forestry of the data distributed and heterogeneous environment.

The hardware and the software of a practical gas-sensor array testing is introduced.According to the characteristic of the semi-conductor gas-sensor,this system heats the gas-sensor array through multi-wave generating circuit,making it possible to detect some essential characteristics that the usual method can not do.The system has provided a good platform for testing the property of multi-sensor.

Introduces a kind of carbon monoxide alarm apparatus that combines together the design with MSP430F149 MCU and the electrochemistry sensor.Take advantage of the MCU′s ultra-low-power and high-integration,and also the electrochemistry sensor′s high-selectivity and the high-accuracy.The alarm apparatus can be used to the condition of battery supply and limited space or portable application.

Highly ordered SnO_2 nanowire arrays embedded in anodic alumina membranes(AAM) have been successfully fabricated by simple Sol-gel method,first SnO_2 colloidal suspensions being filled in the pores of AAM,then annealed at 600℃ for 10h.SEM and TEM images show that SnO_2 nanowires are dense,continuous,uniform diameter and arranged parallelly to another;XRD and SAED analysis together indicate SnO_2 nanowires crystallize with a polycrystalline tetragonal structure;then the growth mechanism of SnO_(2) nanowire arrays is discussed.In the end,nanodevice of a single SnO_2 nanowire between two pt leads is fabricated by focused ion beam deposition(FIB).

Ecological security is critical to sustainable development of human society in the 21st century, which has been paid great attention to by Chinese government since 2003. Firstly, introducing many different understandings on the concept of ecological security, this paper summarizes ecological security concept as follows: Ecological Security is an interdiscipline of natural sciences and social sciences. The concept of ecological security connotes (1) the health, integrity and sustainability of ecosystems and (2) the ecosystems services contributed to human welfare. Ecological security has the characteristics of globality, nonreversibility of ecological damage and chronicity of ecological recovery. Secondly, this paper reviews the research progress on ecological security and puts up a frame of ecological security that is the health, integrity and sustainability of ecosystems, the ecosystems services, and the analysis and assessment of ecological security. The main researches focus on the regional construction and management of ecological security. But the weak researches are on ecological security with globalization and climate change; especially, there is no generally recognized concept of ecological security now, and little new methods of analysis and assessment on ecological security are developed recently. Thirdly, 3 basic theories are concluded on ecological security developing in over 10 years: (1) Assessment of ecosystems health and environmental risk; (2) National interests in environmental /ecological security; and (3) Ecological right theory and legal practice. And several main research methods on ecological security are sum up too. Finally, the research proposal outline in the future is offered: a. to make and bound the concept of ecological security; b. to build the theory for ecological security subject; c. to develop the research methods; d. to build the assessment systems; and e. to make the decision-support model for the regional sustainable development.

Geography is one of the important disciplines for the development of human society In comparison with the available large number of research about geography's future, a little is known about interpreting the digital space of the earth Based on the human social developing issues sustainable development, economic globalization and human actions in information society, the future of geography was studied by means of geographic analysis spatial view, time view, scale view, dynamic view, synthesis, and expression The results showed that there are four changes in future geography: first, research object of geography changes from real geographic space to digital geo space mainly; second, space time view of geographers changes from three dimensional space to multidimensional space and from un reversible time to reversible time; third, research tools change to remote sensing, geographic information system, global positioning system, web and computers;and fourth, the research methods change to simulation, optimization, and control of decision making This article puts forward that the surface of the earth will be studied comprehensively by interpreting the digital space of the earth, which it brings the quantitative analysis of geography to mature