Isotopic Composition of Dissolved Carbonates Meromictic Soda Lake Doroninskoe(Eastern Transbaikalia,Russia)   总被引：1，自引：0，他引：1  

Leonid V. ZAMANA  Svetlana V. BORZENKO 《《地质学报》英文版》2014,88(Z1):395-397

正1 Introduction Meromictic soda Lake Doroninskoe localized in the intermountain area,filled with continental sediments of the Mesozoic,in the upper basin of the river Amur.Coordinates of its location are N51°14'42"E112°14'40",  相似文献   

新型旋转减冲装置对桩基局部冲刷防护试验研究     

张竞  程永舟  程海洋  郑余伟  吕行 《海洋通报》2024,(2)

为减轻海上风电单桩基础周围局部冲刷对其结构安全的影响,提出了一种新型旋转减冲装置。在波流水槽中开展物理模型试验,改变波流条件、装置安装高度、安装距离,记录桩周冲刷发展历时,运用激光地形仪扫描冲刷坑形态,分析各工况下冲刷坑形态差异,验证装置不同安装距离、安装高度下的冲刷防护效果,提出了不同安装位置下的防护效率公式。结果表明：新型旋转减冲装置具有较好的冲刷防护效果,本试验工况下,桩周最大冲刷深度可减小44%左右。装置安装距离对冲刷防护效果影响较小,波流作用下的冲刷防护效果受装置安装高度影响显著,冲刷防护效果随装置安装高度的增加而减弱。  相似文献   

京津冀地区光伏开发空间适宜性及减排效益评估     

刘立程  孙中孝  吴锋  张雪靓  张倩 《地理学报》2022,77(3):665-678

京津冀地区作为中国重要的能源消费基地,近年在产业转型与发展中对清洁能源的需求不断增加。光伏发电是中国“十四五”期间加速能源结构转型,早日实现碳中和目标的关键举措与重要抓手。本文以京津冀为研究区,通过构建“地形—气象—成本”光伏开发适宜性综合评价指标体系,计算了光伏开发适宜性指数,刻画出京津冀地区2018年光伏开发适宜性的空间格局特征,进而定量评估不同开发适宜性情景下光伏发电潜力与减排效益。研究表明：① 京津冀地区光伏开发适宜区占到区域总面积的22%,一般适宜区面积最广,“燕山—太行山”一线是适宜区与不适宜区的主要分界线,各类适宜区主要分布在承德、张家口和保定市3个市。 ② 京津冀地区光伏发电发展潜力巨大,开发非常适宜区和较适宜区的年发电潜力是2018年京津冀地区电力消耗的3倍。③ 光伏发电节能减排效果显著。在将非常适宜区和较适宜区全部开发情景下碳减排量为京津冀2018年排放量的47%。④ 土地利用限制、大型输电网络和储能系统是制约光伏发展的主要因素。总体来看,虽然大规模光伏开发仍存在一定的限制条件与技术瓶颈,但在全球气候变化加剧和社会经济发展进入“低碳脱碳”新常态的背景下,京津冀地区的大规模光伏开发仍是助力区域早日实现碳中和目标、优化能源结构和提升人民福祉的重要途径。  相似文献   

中国旅游业碳减排潜力的空间关联网络结构及其影响因素     

王凯  余芳芳  胡奕  甘畅 《地理科学》2022,42(6):1034-1043

基于2000—2018年中国省际面板数据,利用“自下而上”法和Super-SBM模型测度30个省（区、市）的旅游业碳减排潜力,借助修正的引力模型和社会网络分析方法探究其空间关联网络特征及影响因素。结果表明：①中国旅游业碳减排潜力的空间关联日趋紧密,网络密度和网络关联数呈增长态势,网络效率和网络等级度呈下降态势;②东部区域在空间关联网络中居于核心位置,对降低旅游业碳减排潜力所需要素的掌控与支配能力较强;西部区域在网络中居于边缘位置,难以影响和控制其他省（区、市）;③北京、天津、江苏和上海属于“净受益”板块,广东、浙江和福建属于“经纪人”板块,吉林、内蒙古等23省（区、市）属于“净溢出”板块;④空间邻接关系、经济发展水平差异、产业结构差异、技术创新水平差异和旅游业人数规模差异共同驱动着中国旅游业碳减排潜力空间关联网络结构的形成与演化。  相似文献   

短期增温和降水减少对沙质草地土壤微生物量碳氮和酶活性的影响     

王怀海  黄文达  何远政  牛亚毅  朱远忠 《中国沙漠》2022,42(3):274-281

通过模拟气候变化,探究短期增温和降水减少对沙质草地土壤微生物量碳氮及酶活性的影响,揭示沙质草地土壤微生物量碳氮和酶活性对短期气候变化的响应规律。结果表明：（1）短期增温和降水减少对土壤微生物量碳氮和酶活性均产生显著影响。（2）在自然温度下,与自然降水相比,降水减少40%时土壤微生物量碳（MBC）和微生物氮（MBN）含量最高,增幅分别为87.9%和98.8%;降水减少60%时土壤碱性蛋白酶（S-ALPT）活性最低,降幅达32.8%。（3）在增温条件下,与自然降水相比,降水减少40%时土壤MBC和MBN含量最低,降幅分别为25.67%和48.16%,土壤脲酶（S-UE）活性最高,增幅20.42%。（4）土壤pH与3种土壤酶活性正相关,与土壤微生物量碳氮负相关。土壤微生物量碳氮与土壤纤维素酶（S-CL）活性负相关,与S-UE、S-ALPT活性正相关。  相似文献   

Cultural characteristics of chromium resistant unicellular cyanobacteria isolated from local environment in Pakistan     

Abdul Hameed Shahida Hasnain 《中国海洋湖沼学报》2005,23(4):433-441

Many unicellular cyanobacteria were isolated from different places： fields, ponds, polluted water, and soils from Muredkey and Kasur tannery areas, near Lahore, Pakistan. Different media like BG 11 medium, Bold Basal medium, Chu＇s # 10 medium and Gotham＇s medium, in standard forms and with slight variations of ingredients, and different pH, temperature and light regimes were checked for the optimum growth of the isolates. The isolation pro- cedure was repeated with different concentrations of chromium to select the resistant strains. These selected strains grew on chromium of the range 100-200 μg/ml in BG 11 medium. Cyanobacteria were maintained in solid and liquid media with/without shaking. Cyanobacterial strains were collected from natural habitats that were accompanied by a diversified group of organisms including bacteria, protozoan, and rotifers etc. In order to eliminate these agents termed as contaminants, we used several methods including phenol treatment, use of antibiotic and careful manual picking of unicellular cyanobacteria. Resistance of these strains against different heavy metals （ZnSO4, MnSO4, NiSO4, COCl2, Pb（NO3）3, CuSO4, HgCl2, AgNO3 and CdCl2） and antibiotics （erythromycin, streptomycin, kanamycin, chloramphenicol, neomycin） was evaluated. Optimum temperature was 30℃ with variable pH for the reduction of Cr^6＋ in to Cr^3＋ in majority of strains.  相似文献   

Hydrologic processes at the urban residential scale     

Q. Xiao  E. G. McPherson  J. R. Simpson  S. L. Ustin 《水文研究》2007,21(16):2174-2188

In the face of increasing urbanization, there is growing interest in application of microscale hydrologic solutions to minimize storm runoff and conserve water at the source. In this study, a physically based numerical model was developed to understand hydrologic processes better at the urban residential scale and the interaction of these processes among different best management practices (BMPs). This model simulates hydrologic processes using an hourly interval for over a full year or for specific storm events. The model was applied to treatment and control single‐family residential parcels in Los Angeles, California. Data collected from the control and treatment sites over 2 years were used to calibrate and validate the model. Annual storm runoff to the street was eliminated by 97% with installation of rain gutters, a driveway interceptor, and lawn retention basin. Evaluated individually, the driveway interceptor was the most effective BMP for storm runoff reduction (65%), followed by the rain gutter installation (28%), and lawn converted to retention basin (12%). An 11 m³ cistern did not substantially reduce runoff, but provided 9% of annual landscape irrigation demand. Simulated landscape irrigation water use was reduced 53% by increasing irrigation system efficiency, and adjusting application rates monthly based on plant water demand. The model showed that infiltration and surface runoff processes were particularly sensitive to the soil's physical properties and its effective depth. Replacing the existing loam soil with clay soil increased annual runoff discharge to the street by 63% when climate and landscape features remained unchanged. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Point pattern analysis of north polar crescentic dunes, Mars: A geography of dune self-organization     

Mark A. Bishop 《Icarus》2007,191(1):151-157

The geographic signature of dune distribution and self-organization as measured by the R-statistic offers a viewpoint on the geography of crescentic eolian systems and proposes an index from which to determine the degree of self-organization across a variety of spatial scales. Fields of simple dunes (dome, barchan, barchan-seif) are comparatively less regular in distribution than are those fields, or part thereof, that consist of compound (barchanoid) morphologies whose patterns are more highly regular.  相似文献   

快速Hartley变换及其在图象复原中的应用     

曾文庆  李秋莎 《天文研究与技术》1993,(3)

本文把快速Hartley变换引入到天文数据处理中,提出了计算Cells坐标的公式,编制了FHT算法程序。FHT与Cooley—Tukey的FFT相似,但FHT是实变换,不存在复运算,因此比FFT快得多。利用DHT与离散Fourier变换(DFT)的关系,DFT可以由FHT求出。FHT将广泛地用于谱分析,信号处理,图像处理等领域。  相似文献   

植被分布对小流域产流影响的数值实验          下载免费PDF全文

李妍敏  安翼  刘青泉 《水科学进展》2015,26(2):187-195

基于二维运动波模型,建立了一个适用于小流域场次降雨产汇流过程的动力学模型。通过对典型小流域内不同区域(坡顶、坡中及坡底区域及距离流域出口的远近)种植植被时产流过程的数值模拟,分析了小流域内植被分布对产流过程的影响。结果表明:植被分布及其特性对小流域场次降雨产流有较明显的影响;下游区域种植植被的减水效果和延滞洪峰作用优于上游区域,陡坡区域减水效果优于缓坡区域,且郁闭度越大,这种差别越明显;在该研究条件下,下游区的减水效果可达到上游区的3倍;30%郁闭度条件下减水效果可达10%和20%郁闭度条件下的3倍和1.4倍。  相似文献