Pillar is closely related to the stability and reliability of underground spaces in closed/abandoned mines.The present research introduced a new technique to strengthen square cement mortar columns via fiber-reinforce...Pillar is closely related to the stability and reliability of underground spaces in closed/abandoned mines.The present research introduced a new technique to strengthen square cement mortar columns via fiber-reinforced polymer(FRP)strips to verify the strengthening effect of FRP on pillars.Compared to a fully wrapped FRP jacket,the advantages of FRP strip are cost-effective and easy-to-construct.A series of compression tests as well as theoretical analysis were carried out to explore the mechanical behavior of square cement mortar specimens partially strengthened with FRP strips.The results verified the effectiveness of FRP strips in enhancing the stress and strain of cement mortar.Different from unconfined cement mortar specimens,these FRP-strengthened cement mortar specimens are featured with the double-peaked behaviors,mainly attributed to the stress state transformation from a one-dimensional to a three-dimensional stress state.It also indicated that the enhancement of stress increased with the FRP strip width.Moreover,the brittle-ductile transition ductile failure characteristics were also observed in FRP-confined cement mortar specimens.The ultimate ductility of the cement mortar specimen decreases gradually with the growth of the FRP strip width.The main contribution of this research is to enrich the strengthening techniques for residual pillars.展开更多
The dynamic changes in the distribution of lignin and hemicelluloses (xylans and xyloglucans) in cell walls during the differentiation of secondary xylem in Eucommia ulmoides Oliv. were studied by means of ultraviolet...The dynamic changes in the distribution of lignin and hemicelluloses (xylans and xyloglucans) in cell walls during the differentiation of secondary xylem in Eucommia ulmoides Oliv. were studied by means of ultraviolet light microscopy and transmission electron microscopy combined with immunogold labelling. In the cambial zone and cell expansion zone, xyloglucans were localized both in the tangential and radial walls, but no xylans or lignin were found in these regions. With the formation of secondary wall S-1 layer, lignin occurred in the cell corners and middle lamella, while xylans appeared in S-1 layer, and xyloglucans were localized in the primary walls and middle lamella. In pace with the formation of secondary wall S-2 and S-3 layer, lignification extended to S-1, S-2 and S-3 layer in sequence, showing a patchy style of lignin deposition. Concurrently, xylans distributed in the whole secondary walls and xyloglucans, on the other hand, still localized in the primary walls and middle lamella. The results indicated that along with the formation and lignification of the secondary wall, great changes had taken place in the cell walls. Different parts of cell walls, such as cell corners, middle lamella, primary walls and various layers of secondary walls, had different kinds of hemicelluloses, which formed various cell wall architecture combined with lignin and other cell wall components.展开更多
In order to study the correlations among quality indexes of tobacco leaf and contents of cellulose and lignin in upper leaves of flue-cured tobacco, 48 B2F flue-cured tobacco samples in seven counties of Wulin mountai...In order to study the correlations among quality indexes of tobacco leaf and contents of cellulose and lignin in upper leaves of flue-cured tobacco, 48 B2F flue-cured tobacco samples in seven counties of Wulin mountain area in 2011 and 2012 were used as test materials to measure the contents of cellulose and lignin in tobacco leaves and analyze the differences among varieties and between years. Meanwhile, correlations among contents of cellulose and lignin and appearance quality, physical characteristics, general chemical components and indexes of senso- ry quality were studied. The results showed that the contents of cellulose and lignin had no significant difference among years and varieties. Cellulose content was sig- nificantly correlated with some indexes of appearance qualities, physical indexes, general chemical compositions and sensory qualities. Lignin content was significantly correlated with grayness and oil content but not other quality indexes of tobacco leaf. It could be seen that the differences of cellulose and lignin contents between different years and among varieties were not significant. Cellulose content was closely correlated with quality indexes of tobacco leaf while lignin content had a small effect on tobacco leaf quality.展开更多
Atrial fibrillation （AF） is the most frequent arrhythmia. Due to population aging, AF is a growing epidemic and its importance will continue to increase in the next decades. Although the prevalence of AF is high in ...Atrial fibrillation （AF） is the most frequent arrhythmia. Due to population aging, AF is a growing epidemic and its importance will continue to increase in the next decades. Although the prevalence of AF is high in advanced age, the number of subjects with predisposing factors for AF is even higher. Most of these factors increase the risk of atrial fibro- sis, an important component of atrial arrhythmia mecha- nisms. In fact, the new techniques to detect atrial fibrosis are showing the strong association between atrial fibrosis and AF risk. Regarding predisposing factors for AF, interatrial block （LAB） seems to be a key factor.展开更多
Atrial fibrosis is common in atrial fibrillation （AF）. Experimental studies have provided convincing evidence that fibrotic transformation of atrial myocardium results in deterioration of atrial conduction, increasi...Atrial fibrosis is common in atrial fibrillation （AF）. Experimental studies have provided convincing evidence that fibrotic transformation of atrial myocardium results in deterioration of atrial conduction, increasing anisotropy of impulse propagation and building of boundaries that promote re-entry in the atrial walls that maybe directly relevant for the mechanisms responsible for maintaining AF. Whether or not fibrosis is a result of structural remodelling caused by persistent AF or a manifestation of occult myocardial process that leads to development of arrhythmia is less clear. Human data indicate the presence of association between persistency of AF and the extent of structural changes in atrial myocardium. The role atrial fibrosis plays in the mechanisms of AF, however, may differ between patients with structurally normal hearts, such as lone AF, and those with advanced cardiovascular comorbidities.展开更多
Advances in clinical and fimdamental research, which have been promoted over last decades have led to a well- established understanding of atrial fibrillation （AF） as an epiphenomenon that despite similar manifestat...Advances in clinical and fimdamental research, which have been promoted over last decades have led to a well- established understanding of atrial fibrillation （AF） as an epiphenomenon that despite similar manifestations may have different underlying mechanisms and thus require in- dividualized treatments. With rare exceptions of AF caused by mutations in genes coding ion channels in pa- tients with structurally normal atria, fibrotic replacement of atrial myocardium remains the comer stone of atrial pa- thology in patients with AF.展开更多
Using the mutually coherent function, the self-trapping of the circle partially coherent optical beam in the total internal reflective photonic crystal fiber(TIRPCF) under Compton scattering is studied. The study show...Using the mutually coherent function, the self-trapping of the circle partially coherent optical beam in the total internal reflective photonic crystal fiber(TIRPCF) under Compton scattering is studied. The study shows that the composition of the non-coherent optical beam in the optical spectrum and the diffraction effect are decreased by Compton scattering, and the probability of forming the soliton is greatly increased. The vibration peak value in the propagation, compressed degree, changed cycle, and radius of the soliton are all smaller than those before the scattering, but its coherent radius is larger than that before the scattering. In this propagation, the self-focusing plays a key role.展开更多
基金Project(51925402)supported by the National Science Fund for Distinguished Young Scholars,ChinaProject supported by the New Cornerstone Science Foundation through the XPLORER PRIZE,China+2 种基金Project(202103021222008)supported by the Outstanding Youth Cultivation Project in Shanxi Province,ChinaProject(2022SX-TD010)supported by Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering,ChinaProject(20201102004)supported by Shanxi Science and Technology Major Project,China。
文摘Pillar is closely related to the stability and reliability of underground spaces in closed/abandoned mines.The present research introduced a new technique to strengthen square cement mortar columns via fiber-reinforced polymer(FRP)strips to verify the strengthening effect of FRP on pillars.Compared to a fully wrapped FRP jacket,the advantages of FRP strip are cost-effective and easy-to-construct.A series of compression tests as well as theoretical analysis were carried out to explore the mechanical behavior of square cement mortar specimens partially strengthened with FRP strips.The results verified the effectiveness of FRP strips in enhancing the stress and strain of cement mortar.Different from unconfined cement mortar specimens,these FRP-strengthened cement mortar specimens are featured with the double-peaked behaviors,mainly attributed to the stress state transformation from a one-dimensional to a three-dimensional stress state.It also indicated that the enhancement of stress increased with the FRP strip width.Moreover,the brittle-ductile transition ductile failure characteristics were also observed in FRP-confined cement mortar specimens.The ultimate ductility of the cement mortar specimen decreases gradually with the growth of the FRP strip width.The main contribution of this research is to enrich the strengthening techniques for residual pillars.
文摘The dynamic changes in the distribution of lignin and hemicelluloses (xylans and xyloglucans) in cell walls during the differentiation of secondary xylem in Eucommia ulmoides Oliv. were studied by means of ultraviolet light microscopy and transmission electron microscopy combined with immunogold labelling. In the cambial zone and cell expansion zone, xyloglucans were localized both in the tangential and radial walls, but no xylans or lignin were found in these regions. With the formation of secondary wall S-1 layer, lignin occurred in the cell corners and middle lamella, while xylans appeared in S-1 layer, and xyloglucans were localized in the primary walls and middle lamella. In pace with the formation of secondary wall S-2 and S-3 layer, lignification extended to S-1, S-2 and S-3 layer in sequence, showing a patchy style of lignin deposition. Concurrently, xylans distributed in the whole secondary walls and xyloglucans, on the other hand, still localized in the primary walls and middle lamella. The results indicated that along with the formation and lignification of the secondary wall, great changes had taken place in the cell walls. Different parts of cell walls, such as cell corners, middle lamella, primary walls and various layers of secondary walls, had different kinds of hemicelluloses, which formed various cell wall architecture combined with lignin and other cell wall components.
基金Supported by"Ecological Basic Research of Good Quality Tobacco Leaf with Middle Odor Type"of Major Special Project of China Tobacco Corporation for Tobacco Leaf with Good Quality(TS-02-20110012)~~
文摘In order to study the correlations among quality indexes of tobacco leaf and contents of cellulose and lignin in upper leaves of flue-cured tobacco, 48 B2F flue-cured tobacco samples in seven counties of Wulin mountain area in 2011 and 2012 were used as test materials to measure the contents of cellulose and lignin in tobacco leaves and analyze the differences among varieties and between years. Meanwhile, correlations among contents of cellulose and lignin and appearance quality, physical characteristics, general chemical components and indexes of senso- ry quality were studied. The results showed that the contents of cellulose and lignin had no significant difference among years and varieties. Cellulose content was sig- nificantly correlated with some indexes of appearance qualities, physical indexes, general chemical compositions and sensory qualities. Lignin content was significantly correlated with grayness and oil content but not other quality indexes of tobacco leaf. It could be seen that the differences of cellulose and lignin contents between different years and among varieties were not significant. Cellulose content was closely correlated with quality indexes of tobacco leaf while lignin content had a small effect on tobacco leaf quality.
文摘Atrial fibrillation （AF） is the most frequent arrhythmia. Due to population aging, AF is a growing epidemic and its importance will continue to increase in the next decades. Although the prevalence of AF is high in advanced age, the number of subjects with predisposing factors for AF is even higher. Most of these factors increase the risk of atrial fibro- sis, an important component of atrial arrhythmia mecha- nisms. In fact, the new techniques to detect atrial fibrosis are showing the strong association between atrial fibrosis and AF risk. Regarding predisposing factors for AF, interatrial block （LAB） seems to be a key factor.
文摘Atrial fibrosis is common in atrial fibrillation （AF）. Experimental studies have provided convincing evidence that fibrotic transformation of atrial myocardium results in deterioration of atrial conduction, increasing anisotropy of impulse propagation and building of boundaries that promote re-entry in the atrial walls that maybe directly relevant for the mechanisms responsible for maintaining AF. Whether or not fibrosis is a result of structural remodelling caused by persistent AF or a manifestation of occult myocardial process that leads to development of arrhythmia is less clear. Human data indicate the presence of association between persistency of AF and the extent of structural changes in atrial myocardium. The role atrial fibrosis plays in the mechanisms of AF, however, may differ between patients with structurally normal hearts, such as lone AF, and those with advanced cardiovascular comorbidities.
文摘Advances in clinical and fimdamental research, which have been promoted over last decades have led to a well- established understanding of atrial fibrillation （AF） as an epiphenomenon that despite similar manifestations may have different underlying mechanisms and thus require in- dividualized treatments. With rare exceptions of AF caused by mutations in genes coding ion channels in pa- tients with structurally normal atria, fibrotic replacement of atrial myocardium remains the comer stone of atrial pa- thology in patients with AF.
基金Natural Science Basic Research Project for Education Depart ment of Henan Province Natural ScienceFoundation of Zhumadian City(058001)
文摘Using the mutually coherent function, the self-trapping of the circle partially coherent optical beam in the total internal reflective photonic crystal fiber(TIRPCF) under Compton scattering is studied. The study shows that the composition of the non-coherent optical beam in the optical spectrum and the diffraction effect are decreased by Compton scattering, and the probability of forming the soliton is greatly increased. The vibration peak value in the propagation, compressed degree, changed cycle, and radius of the soliton are all smaller than those before the scattering, but its coherent radius is larger than that before the scattering. In this propagation, the self-focusing plays a key role.
