A New Zircon U–Pb Age of 107.15 Ma for the Dongshan Formation,Boli Basin,Northeast China     

ZHANG Sheng  FANG Shi  SHAO Hongjun  WANG Silin  ZHAO Yun  PING Shuaifei 《《地质学报》英文版》2020,94(2):568-571

Many studies have focused on the Cretaceous evolution of NE China,including the 973 Scientific Exploration Well Work program,which completed two drill holes in this area.The Cretaceous Basin Group of eastern NE China is highly altered,so the evolution,controlling factors and interpretation of the Early Cretaceous Dasanjiang Basin are controversial,and fundamental aspects of the rocks are poorly understood.The Boli Basin is the largest Cretaceous basin within NE China,but the temporal and spatial extent of Mesozoic strata within this basin,especially the Dongshan Formation,arc not well-known.  相似文献   

Deep learning for P-wave arrival picking in earthquake early warning     

Wang Yanwei  Li Xiaojun  Wang Zifa  Shi Jianping  Bao Enhe 《地震工程与工程振动(英文版)》2021,20(2):391-402

Fast and accurate P-wave arrival picking significantly affects the performance of earthquake early warning(EEW)systems.Automated P-wave picking algorithms used in EEW have encountered problems of falsely picking up noise,missing P-waves and inaccurate P-wave arrival estimation.To address these issues,an automatic algorithm based on the convolution neural network(DPick)was developed,and trained with a moderate number of data sets of 17,717 accelerograms.Compared to the widely used approach of the short-term average/long-term average of signal characteristic function(STA/LTA),DPick is 1.6 times less likely to detect noise as a P-wave,and 76 times less likely to miss P-waves.In terms of estimating P-wave arrival time,when the detection task is completed within 1 s,DPick′s detection occurrence is 7.4 times that of STA/LTA in the 0.05 s error band,and 1.6 times when the error band is 0.10 s.This verified that the proposed method has the potential for wide applications in EEW.  相似文献   

我国邮政业综合技术效率评价及其影响因素——基于DEA和Tobit回归模型的分析     

山红梅  杨珂欣  胡海涛  柳朝红  JING Shi 《地域研究与开发》2019,38(1):11-16

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On the radial velocity calibrations in the LAMOST medium-resolution spectroscopic survey of nebulae     

Juan-Juan Ren  Hong Wu  Chao-Jian Wu  Wei Zhang  Jian-Jun Chen  Chih-Hao Hsia  Fan Yang  Chao Liu  Jian-Rong Shi  Yu-Zhong Wu  Hui Zhu  Bin Li  Zhong-Rui Bai  Hao Tian  Yong-Hui Hou 《天文和天体物理学研究(英文版)》2021,(3):1-14

Accurate radial velocity determinations of optical emission lines(i.e.,[NⅡ]λλ6548,6584,Hαand[SⅡ]λλ6717,6731)are very important for investigating the kinematic and dynamic properties of nebulae.The second stage survey program of Large sky Area Multi-Object fiber Spectroscopic Telescope(LAMOST)has started a sub-survey of nebulae(MRS-N)which will spectroscopically observe the optical emission lines of a large sample of nebulae near the Galactic plane.Until now,15 MRS-N plates have been observed from September 2017 to June 2019.Based on fitting the sky emission lines in the red band spectra of MRS-N,we investigate the precision of wavelength calibration and find there are systematic deviations of radial velocities(RVs)from~0.2 to 4 km s^-1 for different plates.Especially for the plates obtained in March 2018,the systematic deviations of RVs can be as large as~4 km s^-1,which then go down to~0.2-0.5 kms^-1 at the end of 2018 and January 2019.An RV calibration function is proposed for these MRS-N plates,which can simultaneously and successfully calibrate the systematic deviations and improve the precision of RVs.  相似文献   

Numerical study on residual current and its impact on mass transport in the Hangzhou Bay and the Changjiang Estuary I. A3-D joint model of the Hangzhou Bay and the Changjiang Estuary     

Zhu Shouxian    Shi Fengyan  Zhu Jianrong  Ding Pingxing .StateKeyLaboratoryofEstuarineandCoastalResearch  EastChinaNormalUniversity  Shanghai  China　　 .MeteorologyInstituteofthePLAScienceandEngineeringUniversity  Nanjing 《海洋学报(英文版)》2001,(1)

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Uptake and distribution of N, P and heavy metals in three dominant salt marsh macrophytes from Yangtze River estuary, China   总被引：4，自引：0，他引：4  

Quan WM  Han JD  Shen AL  Ping XY  Qian PL  Li CJ  Shi LY  Chen YQ 《Marine environmental research》2007,64(1):21-37

We examined the variation in aboveground biomass accumulation and tissue concentrations of nitrogen (N), phosphorus (P), copper (Cu), zinc (Zn) and lead (Pb) in Phragmites australis (common reed), Spartina alterniflora (salt cordgrass), and Scirpus mariqueter throughout the growing season (April-October 2005), in order to determine the differences in net element accumulation and distribution between the three salt marsh macrophytes in the Yangtze River estuary, China. The aboveground biomass was significantly greater in the plots of S. alterniflora than in the plots of P. australis and S. mariqueter throughout the growing season (P<0.05). In August, the peak aboveground biomass was 1246+/-89 gDW/m(2), 2759+/-250 gDW/m(2) and 548+/-54 gDW/m(2) for P. australis, S. alterniflora and S. mariqueter, respectively. The concentrations of nutrients and heavy metals in plant tissues showed similar seasonal patterns. There was a steady decline in element concentrations of the aboveground tissues from April to October. Relative element concentrations in aboveground tissues were at a peak during the spring sampling intervals with minimum levels during the fall. But the concentrations of total nitrogen and total phosphorus in the belowground tissues were relatively constant throughout growing season. Generally, trace metal concentrations in the aboveground tissues of S. mariqueter was the highest throughout the growing season, and the metal concentrations of S. alterniflora tissues (aboveground and belowground) were greater than those of P. australis. Furthermore, the aboveground pools of nutrients and metals were consistently greater for S. alterniflora than for P. australis and S. mariqueter, which suggested that the rapid replacement of native P. australis and S. mariqueter with invasive S. alterniflora would significantly improve the magnitude of nutrient cycling and bioavailability of trace metals in the salt marsh and maybe transport more toxic metals into the water column and the detrital food web in the estuary.  相似文献   

Validation and accuracy analysis of wind products from scatterometer onboard the HY-2B satellite     

Sheng Yang  Bo Mu  Haoqiang Shi  Chaofei Ma  Wu Zhou  Juhong Zou  Mingsen Lin 《海洋学报(英文版)》2023,42(2):74-82

The Chinese marine dynamic environment satellite HY-2B was launched in October 2018 and carries a Ku-band scatterometer. This paper focuses on the accuracies of HY-2B scatterometer wind data during the period from November 2018 to May 2021. The HY-2B wind data are validated against global moored buoys operated by the U.S. National Data Buoy Center and Tropical Atmosphere Ocean, numerical model data by the National Centers for Environmental Prediction, and the Advanced Scatterometer data issued b...  相似文献   

The 2009 Summer Low Temperature in Northeast China and Its Association with Prophase Changes of the Air-Sea System   总被引：1，自引：0，他引：1       下载免费PDF全文

SHEN Baizhu  LIU Shi  LIAN Yi  FENG Guolin  LI Shangfeng  GONG Zhiqiang 《Acta Meteorologica Sinica》2012,26(4):438-453

Under the background of global warming, summer (JJA) low temperature events in Northeast China had not occurred for about 15 yr since 1994, but one such event took place in 2009. By using the NCEP/NCAR reanalysis data, the 100-yr station temperature data at Harbin and Changchun, and the Hadley Center sea surface temperature (SST) data, this paper intends to reveal the cause, circulation background, and influencing factors of this event. Analysis of both horizontal and vertical circulations of a low-value system over Northeast China in summer 2009 during the low temperature event shows that anomalous activities of the Northeast China cold vortex (NECV) played the most direct role. A decadal cooling trend of-0.8 C (10 yr)-1 over 1999-2008 at Changchun and Harbin was found, which is obviously out-of-phase with the linear warming trend (0.2 C (10 yr)-1 ) over 1961-2000 for Northeast China in response to the global warming. The previous winter North Pacific polar vortex (NPPV) area index, significantly positively related to the observed summer temperatures of Harbin and Changchun, was also in a significantly declining tendency. These provide favorable decadal backgrounds for the 2009 low temperature event. Different from the average anomaly field of 500-hPa height for summer 1994-2008 in Northeast China, in the summer of 2009, the Arctic Oscillation (AO) showed a strong negative phase distribution, and significant negative height anomalies dominated Northeast Asia, Aleutian Islands, and North Atlantic. Furthermore, the negative phase of North Pacific Oscillation (NPO) in the winter of 2008 was obviously strong, and it maintained in the spring of 2009. Meanwhile, the SSTA in the equatorial eastern-central Pacific Ocean in the winter of 2008 showed a La Nina phase, but the strength of the La Nina weakened obviously in the spring of 2009. The abnormally strong activities of NECV in June and July of 2009 were related to the disturbances of stationary waves that replaced the original ultra-long waves over the North Pacific region in April and May 2009. The singular value decomposition (SVD) and harmonic analysis results suggest that the anomalous phase of NPO is an important precursor for summer temperature variations over Northeast China, and also a stable planetary-scale component that can be extracted from the atmospheric circulation in addition to the chaotic components on the synoptic scale.  相似文献   

Understanding the X-ray spectrum of anomalous X-ray pulsars and soft gamma-ray repeaters     

Yan-Jun Guo  Shi Dai  Zhao-Sheng Li  Yuan Liu  Hao Tong  Ren-Xin Xu 《天文和天体物理学研究(英文版)》2015,(4):525-536

Hard X-rays above 10 ke V are detected from several anomalous X-ray pulsars(AXPs)and soft gamma-ray repeaters(SGRs),and different models have been proposed to explain the physical origin within the frame of either a magnetar model or a fallback disk system.Using data from Suzaku and INTEGRAL,we study the soft and hard X-ray spectra of four AXPs/SGRs:1RXS J170849–400910,1E 1547.0–5408,SGR 1806–20 and SGR 0501+4516.It is found that the spectra could be well reproduced by the bulk-motion Comptonization(BMC)process as was first suggested by Tr¨umper et al.,showing that the accretion scenario could be compatible with Xray emission from AXPs/SGRs.Simulated results from the Hard X-ray Modulation Telescope using the BMC model show that the spectra would have discrepancies from the power-law,especially the cutoff at～200 ke V.Thus future observations will allow researchers to distinguish different models of the hard X-ray emission and will help us understand the nature of AXPs/SGRs.  相似文献   

http://www.sciencedirect.com/science/article/pii/S1674987111000168   总被引：1，自引：0，他引：1  

Changyi Shi  Mingcai Yan  Qinghua Chi 《地学前缘(英文版)》2011,2(2):261-275

Actual granitoid analytical data of 767 composited samples are presented here.The data source is 6080 samples collected mainly from 750 large- to middle-sized granitoid bodies across China. Data from the composited samples,which includes that of 70 elements,is analyzed according to geological age—Archeozoic(Ar),Proterozoic(Pt),Eopaleozoic(Pz_1),Neopaleozoic(Pz_2),Mesozoic(Mz), and Cenozoic(Cz)—and three major compositional varieties,e.g.alkali-feldspar granite,syenogranite and adamellite.Petrochemical pa...  相似文献