In order to study temperature field distribution in burnt surrounding rock and to determine ranges of burnt surrounding rock, coal-wall coking cycle and heat influence in the underground coal gasification(UCG) stope, ...In order to study temperature field distribution in burnt surrounding rock and to determine ranges of burnt surrounding rock, coal-wall coking cycle and heat influence in the underground coal gasification(UCG) stope, based on the Laplace transform and inversion formula, we studied the temperature analytical solution of one-dimensional unsteady heat conduction for multi-layer overlying strata under the first and the forth kinds of boundary conditions, and we also carried out a numerical simulation of twodimensional unsteady heat conduction by the COMSOL multiphysics. The results show that when the boundary temperature of surrounding rock has a linear decrease because of a directional movement of heat source in the UCG flame working face, the temperature in surrounding rock increases first and then decreases with time, the peak of temperature curve decreases gradually and its position moves inside surrounding rock from the boundary. In the surrounding rock of UCG stope, there is an envelope curve of temperature curve clusters. We analyzed the influence of thermophysical parameters on envelope curves and put forward to take envelope curve as the calculation basis for ranges of burnt surrounding rock, coal-wall coking cycle and heat influence. Finally, the concrete numerical values are given by determining those judgement standards and temperature thresholds, which basically tally with the field geophysical prospecting results.展开更多
In cryogenic wind tunnel tests,piezoelectric stacks are adopted to realize the vibration control of the cantilever sting.However,the free stroke and blocking force of the piezoelectric stack would decrease dramaticall...In cryogenic wind tunnel tests,piezoelectric stacks are adopted to realize the vibration control of the cantilever sting.However,the free stroke and blocking force of the piezoelectric stack would decrease dramatically as the temperature decreases.This paper proposes a convenient and effective warming structure for the piezoelectric stack,which could keep it working at operating temperatures when the ambient temperature drops.The piezoelectric stack actuator is wrapped with the heating film,and this resulting assembly is then wrapped with the aerogel material for thermal insulation.Both ends of the piezoelectric stack actuator make direct contact with the payload structure.Both one-dimensional and two-dimensional theoretical analyses of the heating conduction problem of the piezoelectric stack actuator are conducted.These analyses results are compared with those of the finite element simulation analysis.The finite element method results show a good consistency with the two-dimensional theoretical results,and a slight deviation of only 0.91 K is observed,indicating its potential for protecting piezoelectric stacks at low temperatures.展开更多
Two triterpenoid saponins （compound Ⅰ and Ⅱ） have been isolated from Gymnocladus chinensis Baill., and compound Ⅰ was determined as a new compound. The structure of compound Ⅰ was assigned as 2β,23-dihydroxy-ac...Two triterpenoid saponins （compound Ⅰ and Ⅱ） have been isolated from Gymnocladus chinensis Baill., and compound Ⅰ was determined as a new compound. The structure of compound Ⅰ was assigned as 2β,23-dihydroxy-acacic acid-3-O-α-L-arabinopyranosyl-21-O-{（6S）-2-E-2,6-dimethyl-6-O-[4-O-（6S）-2-E- 2,6 -dimethyl-6-O-β-D-glucopyranosyl-α-L-arabinopyranosyl-2,7-octadienoyl} -28-O-β-D-xylopyranosyl（ 1 →3 ）-β-D-xylopymnosyl （ 1→4）- α-L-rhamnopyranosyl（1→2）-[α-L-rhamnopyranosyl-（1→6）]-β-D-glucopyranoside by extensive MS and NMR studies.展开更多
The controlled synthesis of gold nanocrystals has been the subject of intensive studies for decades because the properties and functions of gold nanomaterials are highly dependent on their particle size, shape, and di...The controlled synthesis of gold nanocrystals has been the subject of intensive studies for decades because the properties and functions of gold nanomaterials are highly dependent on their particle size, shape, and dimensionality. Especially, anisotropic gold nanocrystals, such as nanowires, nanobelts, nanoplates and nanosheets, have attracted much attention due to their striking properties and promising applications in electronics, catalysis, photonics, sensing and biomedicine. In this review, we will summarize the recent developments of one- dimensional （1D） and two-dimensional （2D） gold nanostructures. Various kinds of synthetic methods for preparation of these 1D and 2D gold nanocrystals will be described. Moreover, we will also briefly introduce the properties and potential applications of these 1D and 2D gold nanocrystals.展开更多
In this paper, we reveal a direct relation between the generalized one-dimensional Carinena-Ranada- Santander （ORS） model and the radial part of two-dimensional generalized Higgs model. By this relation, we construc...In this paper, we reveal a direct relation between the generalized one-dimensional Carinena-Ranada- Santander （ORS） model and the radial part of two-dimensional generalized Higgs model. By this relation, we construct a series of quasi-exactly solutions for the two-dimensional Higgs model from a solved generalized CRS model.展开更多
基金supported by the State Key Laboratory of Coal Resources and Safe Mining (No. SKLCRSM10X04)the National Natural Science Foundation of China ((No. 21243006)+1 种基金the Foundation of Ministry of Education of China ((No. 02019)the Priority Academic Program Development of Jiangsu Higher Education Institutions (No.SZBF2011-6-B35)
文摘In order to study temperature field distribution in burnt surrounding rock and to determine ranges of burnt surrounding rock, coal-wall coking cycle and heat influence in the underground coal gasification(UCG) stope, based on the Laplace transform and inversion formula, we studied the temperature analytical solution of one-dimensional unsteady heat conduction for multi-layer overlying strata under the first and the forth kinds of boundary conditions, and we also carried out a numerical simulation of twodimensional unsteady heat conduction by the COMSOL multiphysics. The results show that when the boundary temperature of surrounding rock has a linear decrease because of a directional movement of heat source in the UCG flame working face, the temperature in surrounding rock increases first and then decreases with time, the peak of temperature curve decreases gradually and its position moves inside surrounding rock from the boundary. In the surrounding rock of UCG stope, there is an envelope curve of temperature curve clusters. We analyzed the influence of thermophysical parameters on envelope curves and put forward to take envelope curve as the calculation basis for ranges of burnt surrounding rock, coal-wall coking cycle and heat influence. Finally, the concrete numerical values are given by determining those judgement standards and temperature thresholds, which basically tally with the field geophysical prospecting results.
基金the National Natural Science Foundation of China(No.11872207)Aeronautical Science Foundation of China(No.20180952007)+2 种基金Foundation of National Key Laboratory on Ship Vibration and Noise(No.614220400307)Natural Science Foundation of Jiangsu Province(No.BK20200413)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘In cryogenic wind tunnel tests,piezoelectric stacks are adopted to realize the vibration control of the cantilever sting.However,the free stroke and blocking force of the piezoelectric stack would decrease dramatically as the temperature decreases.This paper proposes a convenient and effective warming structure for the piezoelectric stack,which could keep it working at operating temperatures when the ambient temperature drops.The piezoelectric stack actuator is wrapped with the heating film,and this resulting assembly is then wrapped with the aerogel material for thermal insulation.Both ends of the piezoelectric stack actuator make direct contact with the payload structure.Both one-dimensional and two-dimensional theoretical analyses of the heating conduction problem of the piezoelectric stack actuator are conducted.These analyses results are compared with those of the finite element simulation analysis.The finite element method results show a good consistency with the two-dimensional theoretical results,and a slight deviation of only 0.91 K is observed,indicating its potential for protecting piezoelectric stacks at low temperatures.
基金National Natural Science Foundation of China (GrantNo. 30772639)
文摘Two triterpenoid saponins （compound Ⅰ and Ⅱ） have been isolated from Gymnocladus chinensis Baill., and compound Ⅰ was determined as a new compound. The structure of compound Ⅰ was assigned as 2β,23-dihydroxy-acacic acid-3-O-α-L-arabinopyranosyl-21-O-{（6S）-2-E-2,6-dimethyl-6-O-[4-O-（6S）-2-E- 2,6 -dimethyl-6-O-β-D-glucopyranosyl-α-L-arabinopyranosyl-2,7-octadienoyl} -28-O-β-D-xylopyranosyl（ 1 →3 ）-β-D-xylopymnosyl （ 1→4）- α-L-rhamnopyranosyl（1→2）-[α-L-rhamnopyranosyl-（1→6）]-β-D-glucopyranoside by extensive MS and NMR studies.
文摘The controlled synthesis of gold nanocrystals has been the subject of intensive studies for decades because the properties and functions of gold nanomaterials are highly dependent on their particle size, shape, and dimensionality. Especially, anisotropic gold nanocrystals, such as nanowires, nanobelts, nanoplates and nanosheets, have attracted much attention due to their striking properties and promising applications in electronics, catalysis, photonics, sensing and biomedicine. In this review, we will summarize the recent developments of one- dimensional （1D） and two-dimensional （2D） gold nanostructures. Various kinds of synthetic methods for preparation of these 1D and 2D gold nanocrystals will be described. Moreover, we will also briefly introduce the properties and potential applications of these 1D and 2D gold nanocrystals.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11175089 and 11075077the National Basic Research Program of China under Grant No.2012CB921900
文摘In this paper, we reveal a direct relation between the generalized one-dimensional Carinena-Ranada- Santander （ORS） model and the radial part of two-dimensional generalized Higgs model. By this relation, we construct a series of quasi-exactly solutions for the two-dimensional Higgs model from a solved generalized CRS model.
