The galaxy luminosity function in the LAMOST Complete Spectroscopic Survey of Pointing Area at the Southern Galactic Cap     

Pin-Song Zhao  Hong Wu  Cong Kevin Xu  Ming Yang  Fan Yang  Yi-Nan Zhu  Man I Lam  Jun-Jie Jin  Hai-Long Yuan  Hao-Tong Zhang  Shi-Yin Shen  Jian-Rong Shi  A-Li Luo  Xue-Bing Wu  Yong-Heng Zhao  Yi-Peng Jing 《天文和天体物理学研究(英文版)》2019,(8)

We present optical luminosity functions(LFs) of galaxies in the~(0.1) g,~(0.1) r,~(0.1) i bands, calculated using data in~40 deg~2 sky area of the LAMOST Complete Spectroscopic Survey of Pointing Area(LaCoSSPAr) in the Southern Galactic Cap. Redshifts for galaxies brighter than r = 18.1 were obtained mainly with LAMOST. In each band, LFs derived using both parametric and non-parametric maximum likelihood methods agree well with each other. In the0.1 r band, our fitting parameters of the Schechter function are φ_*=(1.65 ± 0.36) × 10~(-2) h~3 Mpc~(-3), M_*=-20.69 ± 0.06 mag and α =-1.12 ± 0.08,which agree with previous studies. Separate LFs are also derived for emission line galaxies and absorption line galaxies. The LFs of absorption line galaxies show a dip at~(0.1) r ~18.5 and can be fitted well by a double-Gaussian function, suggesting a bimodality in passive galaxies.  相似文献   

Characteristics of the Seismic Waves from a New Active Source Based on Methane Gaseous Detonation   总被引：1，自引：0，他引：1  

WANG Weitao  WANG Xiang  MENG Chuanmin  DONG Shi  WANG Zhigang  XIE Junju  WANG Baoshan  YANG Wei  XU Shanhui  WANG Tao 《中国地震研究》2019,33(2):354-366

Active seismic sources are critical for obtaining high resolution images of the subsurface. For active imaging in urban areas, environment friendly and green seismic sources are required. In present work, we introduce a new type of green active source based on the gaseous detonation of methane and oxygen. When fired in a closed container, the chemical reaction, i.e. gaseous detonation, will produce high pressure air over 150MPa. Seismic waves are produced when high pressure air is quickly released to impact the surroundings. The first field experiment of this active source was carried out in December, 2017 in Jingdezhen, Jiangxi Province, where a series of active sources were excited to explore their potential in mine exploration. In current work, we analyzed the seismic waves recorded by near-field accelerators and a dense short-period seismic array and compared them with those from a mobile airgun source, another kind of active source by releasing high pressure air into water. The results demonstrate that it can be used for high resolution near surface imaging. Firstly, the gaseous detonation productions are harmless CO₂ and water, making it a green explosive source. Secondly, the dominant seismic frequencies are 10-80Hz and a single shot can be recorded up to 15km, making it suitable for local structure investigations. Thirdly, it can be excited in vertical wells, similar to traditional powder explosive sources. It can also act as an additional on-land active source to airgun sources, which requires a suitable water body as intermediate media to generate repeating signals. Moreover, the short duration and high frequency signature of the source signals make it safe with no damage to nearby buildings. These make it convenient to excite in urban areas. As a new explosive source, the excitation equipment and conditions, such as gas ratio, sink depth and air-releasing directions, need further investigation to improve seismic wave generation efficiency.  相似文献   

Dynamic metabolite alterations of Portunus trituberculatus during larval development     

Shi  Ce  Zeng  Tinglan  Li  Ronghua  Wang  Chunlin  Ye  Yangfang  Mu  Changkao 《中国海洋湖沼学报》2019,37(1):361-372

Journal of Oceanology and Limnology - A mass mortality often occurs from molting to the megalopa stage during the larval development of the swimming crab Portunus trituberculatus. Larvae with...  相似文献   

乌加河地震台地电阻率干扰形态识别     

刘伟  柴宁娇  张国清  石伟  王树忠 《地震地磁观测与研究》2019,40(3):64-69

选取乌加河地震台2015-2018年地电阻率观测资料，分析数据异常变化，结合观测环境及实地调查，发现存在降雨、雷电、金属管线、农田灌溉、设备漏电等影响因素，对比分析并总结各类干扰曲线形态、变化幅度、影响时间、干扰频次等特征，以便正确认识并排除地电阻率干扰，为地震异常信息识别提供帮助。  相似文献   

南海沉积物细菌胞外蛋白酶在家族水平上的多样性   总被引：2，自引：0，他引：2  

杨金玉  冯阳阳  陈秀兰  解彬彬  张玉忠  石梅  张熙颖 《海洋学报(英文版)》2019,38(12):73-83

海洋产蛋白酶细菌及其分泌的胞外蛋白酶在降解有机氮以推动海洋氮循环进行方面发挥着重要作用，但目前对这二者多样性的认识非常有限。本研究自南海沉积物中筛选得到90株产蛋白酶细菌，并通过N-端氨基酸序列，分析了其胞外蛋白酶在家族水平上的多样性。16S rRNA基因序列分析的结果表明，筛选的产蛋白酶细菌均属于Gammaproteobacteria纲，且大多数属于Alteromonadales目和Vibrionales目的不同属。对其中14株菌株的14个胞外蛋白酶的N-端氨基酸序列分析表明，所有这些蛋白酶属于金属蛋白酶的M4家族或丝氨酸蛋白酶的S8家族。本研究提供了海洋沉积物产蛋白酶细菌在类群及其胞外蛋白酶在类型上的新细节，这将有助于全面了解微生物酶促降解海洋沉积物有机氮的过程和机理。  相似文献   

福建省复杂地形下旬平均气温分布式模拟     

李威鹏  邱新法  曾燕  施国萍  徐金勤  王丹丹 《热带地理》2019,39(2):229-236

为建立高时空分辨率的福建省复杂地形下气温栅格数据集，利用福建省及其周边33个常规气象站观测资料，基于数字高程模型（DEM）数据，综合考虑海拔、太阳总辐射、地表长波有效辐射对旬平均气温的影响，模拟了福建省复杂地形下旬均温的空间分布。结果表明：1）常规站验证结果显示：各旬气温绝对误差平均值（MAE）最小为0.46℃，最大为2.3℃，全年平均为0.87℃；加密站验证结果显示，MAE最大为2.3℃，最小0.5℃，全年平均为0.96℃。2）模拟结果能反映旬均温的宏观分布规律与局地细节特征。宏观范围内，旬均温受纬度影响较大，由北至南气温逐渐升高，沿海地区旬均温整体高于内陆，山区旬均温明显较低；局地范围内，各坡向上气温差异显著，海拔越高、坡度越大，差异越明显；地形因子对旬平均温的影响具有季节差异，具体表现为冬季时地形因子对旬均温的影响最大，秋季次之，春夏季节中地形因子对旬均温的影响最弱。  相似文献   

Characteristics of Vegetation Carbon,Nitrogen, and C/N Ratio in a Tamarix chinensis Coastal Wetland of China     

Linping Xie  Baodong Wang  Ming Xin  Min Wang  Xiuping He  Qinsheng Wei  Xiaoyong Shi  Xia Sun 《洁净——土壤、空气、水》2019,47(9)

Variations in carbon (C) and nitrogen (N) of the vegetation in a Tamarix chinensis coastal wetland located in Laizhou Bay, China, are analyzed. It is found that T. chinensis accumulates more C and N than the surrounding herbs, and it allocates more C and N in the aboveground parts but less in the roots. Branches store more C, whereas leaves and flowers accumulate more N than other tissues. The C and N contents in the aboveground parts of T. chinensis are mainly influenced by pH, electrical conductivity (EC), water content, and clay content in the top 100 cm of soil as well as the distance from the sea. For the herbs, their C contents vary little in the supratidal zone, but they are higher than those in the intertidal zone. However, N contents in the herbs are higher in the aboveground parts and varied among different communities. The contents of C and N in the herbs are affected by EC, water content as well as the contents of organic C and total nitrogen (TN) in the top 10 cm of soil. The findings confirm that increasing the biomass of T. chinensis is an effective way to increase C sequestration in temperate coastal wetland.  相似文献   

基于主成分分析法和监测数据的阿尔泰山采金废弃矿区人工恢复措施效益分析          下载免费PDF全文

艾沙江·艾力  徐海量  苑塏烨 《干旱区地理》2019,42(2):288-294

本文以阿尔泰山两河源保护区采金废弃矿区为研究区，从地形、土壤、水分和地表植被4个方面出发，结合矿区现有条件，设置11种恢复措施，选取丰富度指数、优势度指数、多样性指数、均匀度指数、生物量、植被盖度、物种数及土石比等7个评价指标，采用主成分分析法，得出不同恢复措施的主成分得分及生态效益排名。结果表明，单一恢复措施，如推平、羊群驻扎、泥浆等基本上是从某一个方面来考虑生态恢复的，存在一定的缺陷，恢复效益排名比较靠后；多种措施相结合，不仅能改善土壤环境，也会引起植物群落多样性格局的变化，生态恢复效益很好；同一种恢复措施，施行年限越长恢复效果越好。  相似文献   

中国人海经济系统环境适应性演化及预警     

李博  史钊源  田闯  苏飞  彭飞 《地理科学》2019,39(4):533-540

基于敏感性-稳定性-响应3维要素构建指标体系,运用熵值法和ARIMA-BP组合预测模型研究中国人海经济系统环境适应性的演化及预警。结果表明：① 2001~2016年中国人海经济系统环境适应性呈稳定上升态势,总体集中于中警状态,期间经历了“人海环境系统比较优势阶段→耦合协调阶段→人海经济系统比较优势阶段”的双螺旋适应过程,预计2017~2020年再次进入相互契合的轻警状态;② 16 a间中国人海经济系统环境适应性波动存在上升期短-衰退期长现象,预计未来4 a人海经济系统环境适应性在经济下行和生态约束背景下的速率不容乐观;③ 权衡人海经济系统和人海环境系统的关系,追求总体效益最大化,延长适应性周期波动中扩张期活动,差别化和灵活性的适应行为是未来主要排警对策。  相似文献   

基于U形卷积神经网络的震相识别与到时拾取方法研究   总被引：8，自引：0，他引：8       下载免费PDF全文

赵明  陈石  房立华  David A Yuen 《地球物理学报》2019,62(8):3034-3042

精确获取震相到时是地震定位和地震走时成像等研究的重要基础.近年来，随着地震台站的不断加密，地震台网监测到的地震数量成倍增长，发展快速、准确、适用性强的震相到时自动拾取算法是地震行业的迫切需求.本文在前人工作基础上，发展了Pg、Sg震相自动识别与到时拾取的U网络算法（Unet_cea），使用汶川余震和首都圈地震台网记录的89344个不同震级、不同信噪比的样本进行训练和测试.研究表明，U网络能够较好地识别Pg、Sg震相类型和拾取到时，Pg、Sg震相的正确识别率分别为81%和79.1%，与人工标注到时的均方根误差分别为0.41 s和0.54 s.U网络在命中率、均方根误差等性能指标上均明显优于STA/LTA和峰度分析自动拾取方法.研究获得的最优模型可以为区域地震台网的自动处理提供辅助.  相似文献