By conformal mapping theory, a trigonometric interpolation method between odd and even sequences in rectangle boundary region was provided, and the conformal mapping function of rectangle-plate with arc radius between...By conformal mapping theory, a trigonometric interpolation method between odd and even sequences in rectangle boundary region was provided, and the conformal mapping function of rectangle-plate with arc radius between complicated region and unite dish region was carried out. Aiming at calculating the vibrating fundamental frequency of special-shaped, elastic simple-supported rectangle-plates, in the in-plane state of constant stress, the vibration function of this complicated plate was depicted by unit dish region. The coefficient of ftmdamental frequency was calculated. Whilst, taking simple-supported elastic rectangle-plates with arc radius as an example, the effects on fundamental frequency caused by the concentrated mass and position, the ratio of the length to width of rectangle, as well as the coefficient of constant in-plane stress were analyzed respectively.展开更多
Focusing on the stability of surrounding rock around the roadway driving along next goaf with a narrow coal pillar, a mechanics model of the triangle block structure of main roof above the roadway is established, and ...Focusing on the stability of surrounding rock around the roadway driving along next goaf with a narrow coal pillar, a mechanics model of the triangle block structure of main roof above the roadway is established, and the sliding stability coefficient K 1 and the rotation stability coefficient K 2 are proposed to describe the stability of the triangle block structure quantitatively. The structure can keep a self stability before and after the roadway excavation, at the stage of mining induced effect, the stability of the structure is lowered, and the structure may become instability with decreasing the coal strength, increasing the mining height of working face and the mining depth.展开更多
The venom apparatus in the large carpenter bees, Xylocopafenestrata （Fabricius） （Hymenoptera： Apidae） has been studied It consists of typical parts, i.e., the venom sac, free filament, Dufour gland, sting shaft a...The venom apparatus in the large carpenter bees, Xylocopafenestrata （Fabricius） （Hymenoptera： Apidae） has been studied It consists of typical parts, i.e., the venom sac, free filament, Dufour gland, sting shaft and accessory sclerites. It is highly sclerotized and concealed by the 7th abdominal tergite and sternite. The venom sac serves as a reservoir for the venom which synthesized by the convoluted gland present in it, which is remarkably uniform to that of ants. The median duct extends from lower portion of venom sac, which measures 2.5 ±0.17 mm （mean ＋ SD） （n = 20） in length. The Dufour gland is a tube-like structure which is inserted in the sting-bulb. The triangular plate is attached at terminal portion of rami, which is in turn attached with lancets. The gonostyli are paired long and tubular structure with 5.29 ± 0.23 mm （n = 20） in length. The sting length is 5.29 ±0.23 mm （n = 20）. The fulcral arm is well-developed with an inverse Y-shaped structure present beneath the sting-bulb. Barbs on the sting shaft are weakly developed in X fenestrata but well developed in ants. The venom apparatus ofX. fenestrata when compared is similar to the bees but differs from that of the wasps and ants.展开更多
Triangular silver nanoplates in aqueous solvent and on the surface of quartz substrate have been synthesized by seed-mediated growth approach in the presence of tannin.It was found that both the amount of tannin and t...Triangular silver nanoplates in aqueous solvent and on the surface of quartz substrate have been synthesized by seed-mediated growth approach in the presence of tannin.It was found that both the amount of tannin and the small triangular silver nanoplate seeds added to the growth solution are the key factors to modulation absorption band of triangular silver nanoplates.The optical in-plane dipole surface plasmon resonance (SPR) bands of these Ag nanoplates can be tuned from 608 nm to 980 nm via tannin deoxidization method.The formation mechanism of triangular silver nanoplates was proposed.The tannin deoxidization method realizes a convenient modulation of the absorption band of Ag nanostructures within the visible near-infrared (IR) region both in aqueous solvent and on substrates under mild conditions.展开更多
By utilizing the panel data of 26 cities in the Yangtze River Delta urban agglomeration of China from 2000 to 2018, this study constructs a panel threshold model to examine the nonlinear relationship between Tourism E...By utilizing the panel data of 26 cities in the Yangtze River Delta urban agglomeration of China from 2000 to 2018, this study constructs a panel threshold model to examine the nonlinear relationship between Tourism Environmental Carrying Capacity(TECC) and Tourism Industry Agglomeration(TIA). TECC is evaluated based on the Driver-Pressure-State-Impact-Response(DPSIR) model, and TIA is estimated by the location quotient index.The analysis reveals that TIA and TECC both show growth trends and significant regional differences among the 26cities, but the latter fluctuates at certain stages. Moreover, TIA has a significant double threshold effect on TECC,which shows that the positive impact of TIA is enhanced initially but then weakens afterwards. Theoretically, this study contributes to enriching the current literature on TECC from the perspective of TIA. Practically, it could help local governments effectively arrange agglomerations to promote the sustainable development of the tourism industry in China.展开更多
This paper presents a numerical analysis of laminar periodic flow and heat transfer in a rectangular constant temperature-surfaced channel with triangular wavy baffles (TWBs).The TWBs were mounted on the opposite wall...This paper presents a numerical analysis of laminar periodic flow and heat transfer in a rectangular constant temperature-surfaced channel with triangular wavy baffles (TWBs).The TWBs were mounted on the opposite walls of the rectangular channel with inline arrangements.The TWBs are placed on the upper and lower walls with attack angle 45?.The numerical is performed with three dif-ferent baffle height ratios (BR=b/H=0.05 0.3) at constant pitch ratio (PR) of 1.0 for the range 100 ≤ Re ≤ 1000.The computational results are shown in the topology of flow and heat transfer.It is found that the heat transfer in the channel with the TWB is more effective than that without baffle.The in-crease in the blockage ratio,BR leads to a considerable increase in the Nusselt number and friction factor.The results indicate that at low BR,a fluid flow is significantly disturbed resulting in inefficient heat transfer.As BR increases,both heat transfer rate in terms of Nusselt number and pressure drop in terms of friction factor increase.Over the range examined,the maximum Nu/Nu0 of 7.3 and f/f0 of 126 are both found with the use of the baffles with BR=0.30 at Re=1000.In addition,the flow structure and temperature field in the channel with TWBs are also reported.展开更多
文摘By conformal mapping theory, a trigonometric interpolation method between odd and even sequences in rectangle boundary region was provided, and the conformal mapping function of rectangle-plate with arc radius between complicated region and unite dish region was carried out. Aiming at calculating the vibrating fundamental frequency of special-shaped, elastic simple-supported rectangle-plates, in the in-plane state of constant stress, the vibration function of this complicated plate was depicted by unit dish region. The coefficient of ftmdamental frequency was calculated. Whilst, taking simple-supported elastic rectangle-plates with arc radius as an example, the effects on fundamental frequency caused by the concentrated mass and position, the ratio of the length to width of rectangle, as well as the coefficient of constant in-plane stress were analyzed respectively.
文摘Focusing on the stability of surrounding rock around the roadway driving along next goaf with a narrow coal pillar, a mechanics model of the triangle block structure of main roof above the roadway is established, and the sliding stability coefficient K 1 and the rotation stability coefficient K 2 are proposed to describe the stability of the triangle block structure quantitatively. The structure can keep a self stability before and after the roadway excavation, at the stage of mining induced effect, the stability of the structure is lowered, and the structure may become instability with decreasing the coal strength, increasing the mining height of working face and the mining depth.
文摘The venom apparatus in the large carpenter bees, Xylocopafenestrata （Fabricius） （Hymenoptera： Apidae） has been studied It consists of typical parts, i.e., the venom sac, free filament, Dufour gland, sting shaft and accessory sclerites. It is highly sclerotized and concealed by the 7th abdominal tergite and sternite. The venom sac serves as a reservoir for the venom which synthesized by the convoluted gland present in it, which is remarkably uniform to that of ants. The median duct extends from lower portion of venom sac, which measures 2.5 ±0.17 mm （mean ＋ SD） （n = 20） in length. The Dufour gland is a tube-like structure which is inserted in the sting-bulb. The triangular plate is attached at terminal portion of rami, which is in turn attached with lancets. The gonostyli are paired long and tubular structure with 5.29 ± 0.23 mm （n = 20） in length. The sting length is 5.29 ±0.23 mm （n = 20）. The fulcral arm is well-developed with an inverse Y-shaped structure present beneath the sting-bulb. Barbs on the sting shaft are weakly developed in X fenestrata but well developed in ants. The venom apparatus ofX. fenestrata when compared is similar to the bees but differs from that of the wasps and ants.
基金Project(10804101) supported by the National Natural Science Foundation of ChinaProject(2007CB815102) supported by the National Basic Research Program of ChinaProject(2007B08007) supported by the Science and Technology Development Foundation of Chinese Academy of Engineering Physics
文摘Triangular silver nanoplates in aqueous solvent and on the surface of quartz substrate have been synthesized by seed-mediated growth approach in the presence of tannin.It was found that both the amount of tannin and the small triangular silver nanoplate seeds added to the growth solution are the key factors to modulation absorption band of triangular silver nanoplates.The optical in-plane dipole surface plasmon resonance (SPR) bands of these Ag nanoplates can be tuned from 608 nm to 980 nm via tannin deoxidization method.The formation mechanism of triangular silver nanoplates was proposed.The tannin deoxidization method realizes a convenient modulation of the absorption band of Ag nanostructures within the visible near-infrared (IR) region both in aqueous solvent and on substrates under mild conditions.
基金The National Social Science Fund Project of China (21BGL02119BGL138)+1 种基金The Macro Decision-making Projects on Culture and Tourism of China Tourism Academy (2021HGJCG04)The Natural Science Planning Project in Shandong Province (ZR202102200015)。
文摘By utilizing the panel data of 26 cities in the Yangtze River Delta urban agglomeration of China from 2000 to 2018, this study constructs a panel threshold model to examine the nonlinear relationship between Tourism Environmental Carrying Capacity(TECC) and Tourism Industry Agglomeration(TIA). TECC is evaluated based on the Driver-Pressure-State-Impact-Response(DPSIR) model, and TIA is estimated by the location quotient index.The analysis reveals that TIA and TECC both show growth trends and significant regional differences among the 26cities, but the latter fluctuates at certain stages. Moreover, TIA has a significant double threshold effect on TECC,which shows that the positive impact of TIA is enhanced initially but then weakens afterwards. Theoretically, this study contributes to enriching the current literature on TECC from the perspective of TIA. Practically, it could help local governments effectively arrange agglomerations to promote the sustainable development of the tourism industry in China.
文摘This paper presents a numerical analysis of laminar periodic flow and heat transfer in a rectangular constant temperature-surfaced channel with triangular wavy baffles (TWBs).The TWBs were mounted on the opposite walls of the rectangular channel with inline arrangements.The TWBs are placed on the upper and lower walls with attack angle 45?.The numerical is performed with three dif-ferent baffle height ratios (BR=b/H=0.05 0.3) at constant pitch ratio (PR) of 1.0 for the range 100 ≤ Re ≤ 1000.The computational results are shown in the topology of flow and heat transfer.It is found that the heat transfer in the channel with the TWB is more effective than that without baffle.The in-crease in the blockage ratio,BR leads to a considerable increase in the Nusselt number and friction factor.The results indicate that at low BR,a fluid flow is significantly disturbed resulting in inefficient heat transfer.As BR increases,both heat transfer rate in terms of Nusselt number and pressure drop in terms of friction factor increase.Over the range examined,the maximum Nu/Nu0 of 7.3 and f/f0 of 126 are both found with the use of the baffles with BR=0.30 at Re=1000.In addition,the flow structure and temperature field in the channel with TWBs are also reported.
