The contents of selenium in soil samples from Guizhou Province, which cover an area of 17.6×104 km2, have been determined. The arithmetic mean value of 947 samples is 0.39 mg/kg, the medium value is 0.30 mg/kg an...The contents of selenium in soil samples from Guizhou Province, which cover an area of 17.6×104 km2, have been determined. The arithmetic mean value of 947 samples is 0.39 mg/kg, the medium value is 0.30 mg/kg and the contents of selenium vary from 0.06 to 1.29 mg/kg in soils developed on the basement rocks, which are controlled by the basement rocks themselves.展开更多
Based on the observations of 36 gPhone gravimeters in 2015, the background noise levels in the seismic frequency band（200-600 s） and sub-seismic band（1-6 h） are calculated. The differences in the PSD（power spectr...Based on the observations of 36 gPhone gravimeters in 2015, the background noise levels in the seismic frequency band（200-600 s） and sub-seismic band（1-6 h） are calculated. The differences in the PSD（power spectrum density） of each band of gPhone gravimetric gauges in different surrounding environments were analyzed and compared with Peterson＇s NLNM（new low-noise model） which is derived from the envelope at the power spectrum density of 75 seismograph stations around the world. The results showed that： the influence of station type on the noise magnitude of gPhone gravimeter is very small; The seismic band noise magnitude（hereinafter referred to as SNM） and the sub-seismic band noise magnitude（hereinafter referred to as SSNM） in the coastal gPhone gravimeter are higher than those of inland stations. Although the local hydrological change has a great influence on the gravity observation, the rainfall is not directly relative to the noise magnitude of the instrument. Except 3 coastal stations, the eight stations which had the highest amplitudes in the SNM were located near the seismic belt. This indicates that the SNM of the gPhone Gravimeter may reflect some seismic information.Compared with the NLNM model, the PSD of the gPhone gravimeter is lower than the NLNM model in the long period band（〈3×10^（-5）Hz）, indicating that the gPhone gravimeter is more suitable for detecting long-period signals（〉10 h） than the seismometer.展开更多
This paper analyses and summarizes the natural radionuclide contents of soil and building materials, radon concentrations and the penetrating radiation levels in Hong Kong. From these, a thorough and objective assessm...This paper analyses and summarizes the natural radionuclide contents of soil and building materials, radon concentrations and the penetrating radiation levels in Hong Kong. From these, a thorough and objective assessment for the terrestrial background irradiation level of Hong Kong was made. Finally, the annual effective dose equivalent received by Hong Kong people due to the natural background irradiation was calculated to be 3.2 mSv.展开更多
Paleosalinity records of the Tianluoshan site are derived from measurations data of clay mineral, boron, strontium, barium, after field sampling in three profiles of the Tianluoshan site. The relative sea level change...Paleosalinity records of the Tianluoshan site are derived from measurations data of clay mineral, boron, strontium, barium, after field sampling in three profiles of the Tianluoshan site. The relative sea level changes are discussed according to the lab results. The record indicates that the region where the Tianluoshan site located has witnessed at least three times of relative sea level high-stand before, during and after the Hemudu period. Based on previous researches, this paper also focuses on discussing several environmental elements, the inter-relationships between environmental condition, human activities and development of the Hemudu culture comprehensively.展开更多
MGAC (Motion Geometric Active Contours), a new variational framework of geometric active contours to track multiple nonrigid moving objects in the clutter background in image sequences is presented. This framework, in...MGAC (Motion Geometric Active Contours), a new variational framework of geometric active contours to track multiple nonrigid moving objects in the clutter background in image sequences is presented. This framework, incorporating with the motion edge information, consists of motion detection and tracking stages. At the motion detection stage, the motion edge map provides an approximate edge map of the moving objects. Then, a tracking stage, merely using the static edge information, is considered to improve the motion detection result. Force field regularization method is used to extend the capture range of the edge attraction force field in both stages. Experiments demonstrate that the proposed framework is valid for tracking multiple nonrigid objects in the clutter background.展开更多
Reading,especially reading at text level,is a process of continuously repeating,consolidating and understanding words,phrases,and sentences.However,from the perspective of psycholinguistics,the compariosn and contrast...Reading,especially reading at text level,is a process of continuously repeating,consolidating and understanding words,phrases,and sentences.However,from the perspective of psycholinguistics,the compariosn and contrast of empirical data from experiments and researches would be evidences to support the idea that reading at text level is mainly influenced by readers' ability of identifying a text's cohesion and coherence,balancing the activation and suppression of background knowledge,as well as readers' utilization of working memory.Readers can make good use of these three aspects in order to advance their understanding of reading at text level.展开更多
<div style="text-align:justify;"> Background concentrations of Fe, Mn, Cu, Zn, Pb, Cd, and Ni were calculated for brown algae <em>Costaria costata</em> from the northwest Sea of Japan. Also...<div style="text-align:justify;"> Background concentrations of Fe, Mn, Cu, Zn, Pb, Cd, and Ni were calculated for brown algae <em>Costaria costata</em> from the northwest Sea of Japan. Also the paper contains refined data on heavy metal concentrations in the widespread distributed brown algae, such as <em>Stephanocystis crassipes, Sargassum pallidum</em> and <em>S. miyabei</em>. As the upper threshold levels of metal background concentrations, the median values plus double medians of absolute deviations from the medians were used (Me + 2MAD). The lower threshold level of the background concentration equal to the physiological need for an element is the median of 15% minimum values in the sampling minus the double median of absolute deviations from the median (Me<sub>15</sub> - 2MAD<sub>15</sub>). The calculated ranges of the background concentrations of metals in algae were compared with concentrations of elements in mac-rophytes collected from habitats with background concentrations of metals in water. </div>展开更多
文摘The contents of selenium in soil samples from Guizhou Province, which cover an area of 17.6×104 km2, have been determined. The arithmetic mean value of 947 samples is 0.39 mg/kg, the medium value is 0.30 mg/kg and the contents of selenium vary from 0.06 to 1.29 mg/kg in soils developed on the basement rocks, which are controlled by the basement rocks themselves.
基金supported by key task project in Sicence for earthquake resilience No.XH17053the National Key Scientific Instrument and Equipment Development Projects of China(Grant No.2012YQ10022506)
文摘Based on the observations of 36 gPhone gravimeters in 2015, the background noise levels in the seismic frequency band（200-600 s） and sub-seismic band（1-6 h） are calculated. The differences in the PSD（power spectrum density） of each band of gPhone gravimetric gauges in different surrounding environments were analyzed and compared with Peterson＇s NLNM（new low-noise model） which is derived from the envelope at the power spectrum density of 75 seismograph stations around the world. The results showed that： the influence of station type on the noise magnitude of gPhone gravimeter is very small; The seismic band noise magnitude（hereinafter referred to as SNM） and the sub-seismic band noise magnitude（hereinafter referred to as SSNM） in the coastal gPhone gravimeter are higher than those of inland stations. Although the local hydrological change has a great influence on the gravity observation, the rainfall is not directly relative to the noise magnitude of the instrument. Except 3 coastal stations, the eight stations which had the highest amplitudes in the SNM were located near the seismic belt. This indicates that the SNM of the gPhone Gravimeter may reflect some seismic information.Compared with the NLNM model, the PSD of the gPhone gravimeter is lower than the NLNM model in the long period band（〈3×10^（-5）Hz）, indicating that the gPhone gravimeter is more suitable for detecting long-period signals（〉10 h） than the seismometer.
文摘This paper analyses and summarizes the natural radionuclide contents of soil and building materials, radon concentrations and the penetrating radiation levels in Hong Kong. From these, a thorough and objective assessment for the terrestrial background irradiation level of Hong Kong was made. Finally, the annual effective dose equivalent received by Hong Kong people due to the natural background irradiation was calculated to be 3.2 mSv.
基金National Science and Technology Supporting Project, No.2006BAK21B02 National Natural Science Foundation of China, No.40671016+4 种基金 National Key and Basic Development Research Project of China, No.2003CB415201 Program of Archeological Research Center of Peking University Youth Science Foundation of NSFC, No： 40901012 ^14C ages were tested by Scientific and Technological Archaeology and Heritage Conservation Laboratory in School of Archeology and Museology, Peking University the percentage content of clay minerals was determined by Dr. Wang Hejin in School of Earth and Space Sciences, Peking University, who was helpful in extracting the clay minerals trace elements were determined by the Hebei Provincial Institute of Geological Survey.
文摘Paleosalinity records of the Tianluoshan site are derived from measurations data of clay mineral, boron, strontium, barium, after field sampling in three profiles of the Tianluoshan site. The relative sea level changes are discussed according to the lab results. The record indicates that the region where the Tianluoshan site located has witnessed at least three times of relative sea level high-stand before, during and after the Hemudu period. Based on previous researches, this paper also focuses on discussing several environmental elements, the inter-relationships between environmental condition, human activities and development of the Hemudu culture comprehensively.
文摘MGAC (Motion Geometric Active Contours), a new variational framework of geometric active contours to track multiple nonrigid moving objects in the clutter background in image sequences is presented. This framework, incorporating with the motion edge information, consists of motion detection and tracking stages. At the motion detection stage, the motion edge map provides an approximate edge map of the moving objects. Then, a tracking stage, merely using the static edge information, is considered to improve the motion detection result. Force field regularization method is used to extend the capture range of the edge attraction force field in both stages. Experiments demonstrate that the proposed framework is valid for tracking multiple nonrigid objects in the clutter background.
文摘Reading,especially reading at text level,is a process of continuously repeating,consolidating and understanding words,phrases,and sentences.However,from the perspective of psycholinguistics,the compariosn and contrast of empirical data from experiments and researches would be evidences to support the idea that reading at text level is mainly influenced by readers' ability of identifying a text's cohesion and coherence,balancing the activation and suppression of background knowledge,as well as readers' utilization of working memory.Readers can make good use of these three aspects in order to advance their understanding of reading at text level.
文摘<div style="text-align:justify;"> Background concentrations of Fe, Mn, Cu, Zn, Pb, Cd, and Ni were calculated for brown algae <em>Costaria costata</em> from the northwest Sea of Japan. Also the paper contains refined data on heavy metal concentrations in the widespread distributed brown algae, such as <em>Stephanocystis crassipes, Sargassum pallidum</em> and <em>S. miyabei</em>. As the upper threshold levels of metal background concentrations, the median values plus double medians of absolute deviations from the medians were used (Me + 2MAD). The lower threshold level of the background concentration equal to the physiological need for an element is the median of 15% minimum values in the sampling minus the double median of absolute deviations from the median (Me<sub>15</sub> - 2MAD<sub>15</sub>). The calculated ranges of the background concentrations of metals in algae were compared with concentrations of elements in mac-rophytes collected from habitats with background concentrations of metals in water. </div>
