A single freedom degree model of drilling bit-rock was established according to the vibration mechanism and its dynamic characteristics. Moreover, a novel identification method of rock and soil parameters for vibratio...A single freedom degree model of drilling bit-rock was established according to the vibration mechanism and its dynamic characteristics. Moreover, a novel identification method of rock and soil parameters for vibration drilling based on the fuzzy least squares(FLS)-support vector machine(SVM) was developed, in which the fuzzy membership function was set by using linear distance, and its parameters, such as penalty factor and kernel parameter, were optimized by using adaptive genetic algorithm. And FLS-SVM identification on rock and soil parameters for vibration drilling was made by changing the input/output data from single freedom degree model of drilling bit-rock. The results of identification simulation and resonance column experiment show that relative error of natural frequency for some hard sand from identification simulation and resonance column experiment is 1.1% and the identification precision based on the fuzzy least squares-support vector machine is high.展开更多
Diabetes has become the epidemic of the 21 st century, and with over 90% patients with diabetes becoming at a risk of developing retinopathy, diabetic retinopathy has emerged as a major public health concern. In spite...Diabetes has become the epidemic of the 21 st century, and with over 90% patients with diabetes becoming at a risk of developing retinopathy, diabetic retinopathy has emerged as a major public health concern. In spite of cutting edge research in the field, how retina and its vasculature are damaged by the diabetic milieu remains ambiguous. The environmental factors, life style or disease process can also bring in modifications in the DNA, and these epigenetic modifications either silence or activate a gene without altering the DNA sequence. Diabetic environment up- or downregulates a number of genes in the retina, and emerging research has shown that it also facilitates epigenetic modifications. In the pathogenesis of diabetic retinopathy, the genes associated with important enzymes(e.g., mitochondrial superoxide dismutase, matrix metalloproteinase-9 and thioredoxin interacting protein) and transcriptional factors are epigenetically modified, the enzymes responsible for these epigenetic modifications are either activated or inhibited, and the levels of micro RNAs are altered. With epigenetic modifications taking an important place in diabetic retinopathy, it is now becoming critical to evaluate these modifications, and understand their impact on this slow progressing blinding disease.展开更多
This paper reports an integrated study of in sire U-Pb geochronology and elemental geochemistry of zircons from the Xianglushan iron-polymetallic deposit in western Guizhou Province, Southwest China. Genetic relations...This paper reports an integrated study of in sire U-Pb geochronology and elemental geochemistry of zircons from the Xianglushan iron-polymetallic deposit in western Guizhou Province, Southwest China. Genetic relationship between this new type of deposit and unroofing of the Emeishan large igneous province （ELIP） is focused. Along with the zoning pattern in spatial distribution of diverse weathering-related deposits along the southern and southeastern margins of the ELIP, it is suggested that the genesis of the iron-polymetallic deposit was specialized by factors of coastal paleogeography in hot-humid climate, where iron-enriched laterites formed, and repetitive marine transgression-regression occurred during the Late Permian.展开更多
基金Project(2012BAK09B02-05) supported by the National Key Technology R&D Program of China during the Twelfth Five-year PeriodProject(51274250) supported by the National Natural Science Foundation of China
文摘A single freedom degree model of drilling bit-rock was established according to the vibration mechanism and its dynamic characteristics. Moreover, a novel identification method of rock and soil parameters for vibration drilling based on the fuzzy least squares(FLS)-support vector machine(SVM) was developed, in which the fuzzy membership function was set by using linear distance, and its parameters, such as penalty factor and kernel parameter, were optimized by using adaptive genetic algorithm. And FLS-SVM identification on rock and soil parameters for vibration drilling was made by changing the input/output data from single freedom degree model of drilling bit-rock. The results of identification simulation and resonance column experiment show that relative error of natural frequency for some hard sand from identification simulation and resonance column experiment is 1.1% and the identification precision based on the fuzzy least squares-support vector machine is high.
文摘Diabetes has become the epidemic of the 21 st century, and with over 90% patients with diabetes becoming at a risk of developing retinopathy, diabetic retinopathy has emerged as a major public health concern. In spite of cutting edge research in the field, how retina and its vasculature are damaged by the diabetic milieu remains ambiguous. The environmental factors, life style or disease process can also bring in modifications in the DNA, and these epigenetic modifications either silence or activate a gene without altering the DNA sequence. Diabetic environment up- or downregulates a number of genes in the retina, and emerging research has shown that it also facilitates epigenetic modifications. In the pathogenesis of diabetic retinopathy, the genes associated with important enzymes(e.g., mitochondrial superoxide dismutase, matrix metalloproteinase-9 and thioredoxin interacting protein) and transcriptional factors are epigenetically modified, the enzymes responsible for these epigenetic modifications are either activated or inhibited, and the levels of micro RNAs are altered. With epigenetic modifications taking an important place in diabetic retinopathy, it is now becoming critical to evaluate these modifications, and understand their impact on this slow progressing blinding disease.
基金supported by the National Natural Science Foundation of China(Grant Nos.41373037 and 41173048)Integrated Exploration Project of the Weining-Shuicheng Iron-Polymetallic Deposits,Guizhou Province
文摘This paper reports an integrated study of in sire U-Pb geochronology and elemental geochemistry of zircons from the Xianglushan iron-polymetallic deposit in western Guizhou Province, Southwest China. Genetic relationship between this new type of deposit and unroofing of the Emeishan large igneous province （ELIP） is focused. Along with the zoning pattern in spatial distribution of diverse weathering-related deposits along the southern and southeastern margins of the ELIP, it is suggested that the genesis of the iron-polymetallic deposit was specialized by factors of coastal paleogeography in hot-humid climate, where iron-enriched laterites formed, and repetitive marine transgression-regression occurred during the Late Permian.
