The single-station microtremor method is one of the fastest,most reliable,and cheapest methods used to identify dynamic soil properties.This study utilizes 49 single-station microtremor measurements to identify the dy...The single-station microtremor method is one of the fastest,most reliable,and cheapest methods used to identify dynamic soil properties.This study utilizes 49 single-station microtremor measurements to identify the dynamic soil properties of the Hilalkent quarter of the Yakutiye district in Erzurum.Soil dominant frequency and the amplification factor were calculated by using the Nakamura horizontal/vertical spectral ratio(H/V)method.While the soil dominant frequency values varied between 0.4 Hz and 10 Hz,the soil amplification factor changed between 1 and 10.Higher H/V values were acquired with lower frequency values.The vulnerability index(K_(g))and shear strain parameters that are utilized to estimate the damage that may be caused by an earthquake were mapped.Especially in the west side of the study area,higher K_(g) values were observed.The shear strain map was created with 0.25 g,0.50 g and 0.75 g bedrock accelerations,and soil types that lost elasticity during an earthquake were identified.The average shear wave velocity for the first 30 m(V_(s30))was calculated.Finally,it was observed that the western part of the study area,which resulted in a higher period and higher H/V,higher K_(g) and lower V_(s30) values,presents a higher risk of damage during an earthquake.展开更多
We demonstrate here seven pure cyclic samples, which belongs to two series of oligoesters, cyclic oligo（trimethylene terephthalate）s （COTTs） and cyclic oligo（butylene terephthalate）s （COBTs）, showing odd-even ...We demonstrate here seven pure cyclic samples, which belongs to two series of oligoesters, cyclic oligo（trimethylene terephthalate）s （COTTs） and cyclic oligo（butylene terephthalate）s （COBTs）, showing odd-even effect of degree of oligomerization （repeating units number） on properties. The pentamer of COTT and trimer of COBT show much lower melting temperature, and the trimer of COTT and trimer of COBT show significant lower refractive index, which can be ascribed to the low packing density of cyclic oligoesters with odd number of degree of oligomerization. Our results reveal the discrete property change as a function of cyclic size of oligomers, which can be used to design materials with special properties.展开更多
Carbon preference index (CPI) of long-chain n-alkanes preserved in surface soil increases gradually from southeastern China to the north margin of Loess Plateau.Along this latitudinal transect,the CPI value correlates...Carbon preference index (CPI) of long-chain n-alkanes preserved in surface soil increases gradually from southeastern China to the north margin of Loess Plateau.Along this latitudinal transect,the CPI value correlates to relative humidity,precipitation,and temperature with a negative linear relationship,respectively,whereas the correlation of CPI to temperature is relatively weak.In the Wuyi,Shennongjia,and Tianshan Mountains,CPI values do not change systemically with altitude increasing (or temperature decreasing).However,mean value of CPI for the individual mountain increases in turn from the humid mountain to the arid.These results jointly suggest that aridity (or humidity) is a dominate climate factor in altering soil CPI value.High CPI values of geological records therefore indicate the arid paleoclimate.Though long-chain n-alkanes in soil are derived mainly from leaf wax of terrestrial vascular plants,the regular latitudinal variations of soil CPI might not be caused by the change of vegetation.We speculate that increased long-chain n-alkanes from microbes and/or enhanced biodegradation in the humid climate lead to the decrease of soil CPI.展开更多
文摘The single-station microtremor method is one of the fastest,most reliable,and cheapest methods used to identify dynamic soil properties.This study utilizes 49 single-station microtremor measurements to identify the dynamic soil properties of the Hilalkent quarter of the Yakutiye district in Erzurum.Soil dominant frequency and the amplification factor were calculated by using the Nakamura horizontal/vertical spectral ratio(H/V)method.While the soil dominant frequency values varied between 0.4 Hz and 10 Hz,the soil amplification factor changed between 1 and 10.Higher H/V values were acquired with lower frequency values.The vulnerability index(K_(g))and shear strain parameters that are utilized to estimate the damage that may be caused by an earthquake were mapped.Especially in the west side of the study area,higher K_(g) values were observed.The shear strain map was created with 0.25 g,0.50 g and 0.75 g bedrock accelerations,and soil types that lost elasticity during an earthquake were identified.The average shear wave velocity for the first 30 m(V_(s30))was calculated.Finally,it was observed that the western part of the study area,which resulted in a higher period and higher H/V,higher K_(g) and lower V_(s30) values,presents a higher risk of damage during an earthquake.
基金financially supported by the National"973"Project(No.2011CB606004)the National Natural Science Foundation of China(Nos.21274099,21234005 and 21474067)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘We demonstrate here seven pure cyclic samples, which belongs to two series of oligoesters, cyclic oligo（trimethylene terephthalate）s （COTTs） and cyclic oligo（butylene terephthalate）s （COBTs）, showing odd-even effect of degree of oligomerization （repeating units number） on properties. The pentamer of COTT and trimer of COBT show much lower melting temperature, and the trimer of COTT and trimer of COBT show significant lower refractive index, which can be ascribed to the low packing density of cyclic oligoesters with odd number of degree of oligomerization. Our results reveal the discrete property change as a function of cyclic size of oligomers, which can be used to design materials with special properties.
基金supported jointly by National Natural Science Foundation of China (Grant No. 41103001)Knowledge Innovation Program of Chinese Academy of Sciences (Grant Nos. KZCX2-YW-Q1-15,KZCX2-YW-Q1-03)
文摘Carbon preference index (CPI) of long-chain n-alkanes preserved in surface soil increases gradually from southeastern China to the north margin of Loess Plateau.Along this latitudinal transect,the CPI value correlates to relative humidity,precipitation,and temperature with a negative linear relationship,respectively,whereas the correlation of CPI to temperature is relatively weak.In the Wuyi,Shennongjia,and Tianshan Mountains,CPI values do not change systemically with altitude increasing (or temperature decreasing).However,mean value of CPI for the individual mountain increases in turn from the humid mountain to the arid.These results jointly suggest that aridity (or humidity) is a dominate climate factor in altering soil CPI value.High CPI values of geological records therefore indicate the arid paleoclimate.Though long-chain n-alkanes in soil are derived mainly from leaf wax of terrestrial vascular plants,the regular latitudinal variations of soil CPI might not be caused by the change of vegetation.We speculate that increased long-chain n-alkanes from microbes and/or enhanced biodegradation in the humid climate lead to the decrease of soil CPI.
