Venusian coronae are large(60-2600 km diameter)tectono-magmatic features characterized by quasi-circular graben-fissure systems and topographic features such as a central dome,central depression,circular rim or circular
BACKGROUND: No retrievable and repositionable second generation transcatheter aortic valve is available in China. Here, we report the first-in-man implantation of the retrievable and repositionable VenusA-Plus valve. ...BACKGROUND: No retrievable and repositionable second generation transcatheter aortic valve is available in China. Here, we report the first-in-man implantation of the retrievable and repositionable VenusA-Plus valve. METHODS: A 76-year-old patient with symptomatic severe aortic stenosis and high surgical risk(STS 13.8%) was recommended for transcatheter aortic valve replacement(TAVR) by heart valve team. Type 0 bicuspid aortic valve with asymmetric calcification was identified by dual source computed tomography, and the unfavorable anatomies increased the possibility of malposition and paravalvular leakage during TAVR. Therefore, we used the retrievable and repositionable Venus APlus valve for the patient.RESULTS: Transfemoral TAVR was performed under local anesthesia with sedation, and a 26-mm VenusA-Plus valve was successfully implanted. No transvalvular pressure gradient and trace paravalvular leakage were found. CONCLUSION: The successful first-in-man implantation indicates the retrievable and repositionable Venus A-Plus valve is feasible in complicated TAVR cases such as bicuspid aortic valve.展开更多
Aquaculture in saline-alkaline water has a major problem： microalgal blooming causes the pH of water to increase dramatically, thereby causing damage to the reared organisms. To solve this problem, we set out to find...Aquaculture in saline-alkaline water has a major problem： microalgal blooming causes the pH of water to increase dramatically, thereby causing damage to the reared organisms. To solve this problem, we set out to find a candidate filter-feeding bivalve species suitable for saline-alkaline water to graze on microalgae and to control the pH. In the current study, we investigated the effect of carbonate alkalinity （CA, 2.5, 10.0, and 20.0 meq/L） and pH （8.0, 8.5, and 9.0） on the grazing capacity （GC） of the clam Cyclina sinensis. Additionally, the effect of clam size （small, medium, and large） and microalgae species （Nannochloropsis oculata, Chaetoceros miielleri, and lsochrysis galbana）, and the effect of bottom sediment characteristic （mud, sandy mud, and muddy sand） and thickness （3 and 6 cm） were analyzed as well. The results show that the GC on L galbana was the highest and small size had the maximum GC/W （W： wet weight including body and shells）. No significant differences were observed between sediment type and thickness. Regarding CA and pH, a significant decrease in GC by the pH or by their interaction was found. The GC ofC. sinensis was not greatly reduced in the treatments ofpH≤8.5 and CA≤20.0, and also not affected by bottom sediment type, indicating that this clam is capable to manage microalgal concentrations and might be a candidate species for pH reduction in saline-alkaline water ponds.展开更多
In recent years,more and more creatures in nature have become the source of inspiration for people to study bionic soft robots.Many such robots appear in the public’s vision.In this paper,a Venus flytrap robot simila...In recent years,more and more creatures in nature have become the source of inspiration for people to study bionic soft robots.Many such robots appear in the public’s vision.In this paper,a Venus flytrap robot similar to the biological Venus flytrap in appearance was designed and prepared.It was mainly cast by Polydimethylsiloxane(PDMs)and driven by the flexible material of Ionic Polymer Metal Composites(IPMCs).Combining with ANSYS and related experiments,the appropriate voltage and the size of IPMC were determined.The results showed that the performance of the Venus flytrap robot was the closest to the biological Venus flytrap when the size of IPMC length,width and driving voltage reach to 3 cm,1 cm and 5.5 V,respectively.Moreover,the closing speed and angle reached 8.22°/s and 37°,respectively.Finally,the fly traps also could be opened and closed repeatedly and captured a small ball with a mass of 0.3 g firmly in its middle and tip.展开更多
With Venus Express magnetic field measurements at 32 Hz from 2006 to 2012, we investigate statistically the magnetic fluctuations in the near-Venusian space. The global spatial distribution of their spectral scaling f...With Venus Express magnetic field measurements at 32 Hz from 2006 to 2012, we investigate statistically the magnetic fluctuations in the near-Venusian space. The global spatial distribution of their spectral scaling features is presented in MHD and kinetic regimes. It can be observed that turbulence is a common phenomenon in the solar wind in both regimes. The solar wind MHD turbulence is modified at the Venusian bow shock;MHD turbulence is absent in the Venusian magnetosheath but present at the magnetosheath boundary layer. Pre-existing kinetic turbulence from the far upstream solar wind is modified in the near solar wind region, while kinetic turbulence can be extensively observed throughout the Venusian magnetosheath and in some regions of the induced magnetosphere. Our results reveal that, in the near-Venusian space, energy cascade can be developed at the boundary between magnetosheath and wake, and the turbulence-related dissipation of magnetic energy occurs extensively in the magnetosheath and the induced magnetosphere.展开更多
The Pre-Raphaelite painter Edward Burne-Jones(1833-1898)conceived the subject of The Mirror of Venus between 1865 and 1867.He painted two versions:a small version in gouache and oil and a larger version in oil on canv...The Pre-Raphaelite painter Edward Burne-Jones(1833-1898)conceived the subject of The Mirror of Venus between 1865 and 1867.He painted two versions:a small version in gouache and oil and a larger version in oil on canvas.In composing this subject Burne-Jones was inspired by the poetic and chromatic description of a lyrical stanza on“The Hill of Venus”in the long epic poem Earthly Paradise,written by his close friend and collaborator William Morris.1 This study comprises three parts:Burne-Jones’s history of the paintings,his iconographical sources,and an iconological interpretation of The Mirror of Venus.展开更多
The Venusian dayside ionosphere, similar to other planetary ionospheres, is produced primarily by ionization of its neutral upper atmosphere due to solar extreme ultraviolet (EUV) radiation. It has become clear that t...The Venusian dayside ionosphere, similar to other planetary ionospheres, is produced primarily by ionization of its neutral upper atmosphere due to solar extreme ultraviolet (EUV) radiation. It has become clear that the expansion of the ionosphere may be strongly controlled by the EUV level, as exhibited in data collected by the Pioneer Venus Orbiter (PVO) during one solar cycle (1978 1992). However, the EUV-dependence of the Venusian dayside ionopause altitude, which defines the outer boundary of the ionosphere, remains obscure because the PVO crossed the dayside ionopause only during the solar maximum;its periapsis lifted too high during the solar minimum. Recently, during the period 2006 2014, which included the longest and quietest solar minimum of the past several decades, Venus Express (VEX) provided measurements of the photoelectron boundary (PEB) over the northern high-latitude region. Since the photoelectron boundary is closely related to the ionopause, we have an opportunity to analyze the EUV effect on the dayside ionopause by combining PVO and VEX observations. We have evaluated and then reduced the orbit bias effect in data from both PVO and VEX, and then used the results to derive a relationship between solar EUV level and the dayside ionopause altitude. We find that the dayside ionopause altitude increases as the solar EUV level increases, which is consistent with theoretical expectations.展开更多
This paper is devoted to the development and testing of the optimal procedures for retrieving biophysical crop variables by exploiting the spectral information of current multispectral optical satellite Sentinel-2 and...This paper is devoted to the development and testing of the optimal procedures for retrieving biophysical crop variables by exploiting the spectral information of current multispectral optical satellite Sentinel-2 and Venus and in view of the advent of the new Sino-EU hyperspectral satellite(e.g.,PRISMA,EnMAP,and GF-5).Two different methodologies devoted to the estimation of biophysical crop variables Leaf area index(LAI)and Leaf chlorophyll content(Cab)were evaluated:non-kernel-based and kernel-based Machine Learning Regression Algorithms(MLRA);Sentinel-2 and Venus data comparison for the analysis of the durum wheat-growing season.Results show that for Sentinel-2 data,Gaussian Process Regression(GPR)was the best performing algorithm for both LAI(R 2=0.89 and RMSE=0.59)and Cab(R 2=0.70 and RMSE=8.31).Whereas,for PRISMA simulated data the Kernel Ridge Regression(KRR)was the best performing algorithm among all the other MLRA(R 2=0.91 and RMSE=0.51)for LAI and(R 2=0.83 and RMSE=6.09)for Cab,respectively.Results of Sentinel-2 and Venus data for durum wheat-growing season were consistent with ground truth data and confirm also that SWIR bands,which are used as tie-points in the PROSAIL inversion,are extremely useful for an accurate retrieving of crop biophysical parameters.展开更多
Venus flytrap can sense the very small insects that touch its tactile receptors,known as trigger hairs,and thus capture prey to maintain its nutrient demand.However,there are few studies on the trigger hair and its mo...Venus flytrap can sense the very small insects that touch its tactile receptors,known as trigger hairs,and thus capture prey to maintain its nutrient demand.However,there are few studies on the trigger hair and its morphological structure and material properties are not fully understood.In this study,the trigger hair is systematically characterized with the help of diff erent instruments.Results show that trigger hair is a special cantilever beam structure and it has a large longitudinal diameter ratio.Besides,it is composed of a hair lever and a basal podium,and there is a notch near the hair base.The crosssection of the trigger hair is approximately a honeycomb structure,which is composed of many holes.Methods to measure mechanical properties of trigger hair are introduced in this paper.Based on the mechanical tests,trigger hair proved to be a variable stiff ness structure and shows a high sensitivity to the external force.These features can provide supports for the understanding of the high-sensitivity sensing mechanism of trigger hairs from the perspective of structure and material,and off er inspirations for the development of high-performance tactile sensors.展开更多
Stagnant lid planets are characterized by a globe-encircling,conducting lid that is thick and strong,which leads to reduced global surface heat flows.Consequently,the mantles of such planets can have warmer interiors ...Stagnant lid planets are characterized by a globe-encircling,conducting lid that is thick and strong,which leads to reduced global surface heat flows.Consequently,the mantles of such planets can have warmer interiors than Earth,and interestingly,a pyrolitic mantle composition under warmer conditions is predicted to have a distinctly different mantle transition zone compared to the present-day Earth(Hirose,2002;Stixrude and Lithgow-Bertelloni,2011;Ichikawa et al.,2014;Dannberg et al,2022).Instead of olivine primarily transforming into its higher-pressure polymorphs such as wadsleyite and then ringwoodite,at pressures corresponding to 410 km and 520 km depth in Earth,respectively,it instead transforms into a mineral assemblage of wadsleyite,majorite,and ferropericlase(WMF),and then to majorite+ferropericlase(MF),before finally transforming into bridgmanite at pressures corresponding to 660 km depth in Earth(Stixrude and Lithgow-Bertelloni,2011;Ichikawa et al.,2014).Convective motions in stagnant lid planets are dominated by small-scale instabilities(cold drips)forming within the mobile rheological sublayer under the rigid lid.Using ASPECT and a thermodynamic model of a pyrolitic mantle composition generated by HeFESTo,we show that under certain conditions,the small drips can pond atop the WMF-MF mineral phase transition.The barrier to convective flow arises from the WMF mineral phase assemblage having an effective negative thermal expansivity(Stixrude and Lithgow-Bertelloni,2022).Although large-scale downwellings that typically occur within mobile lid planets are able to pass through the WMF zone without difficulty(Dannberg et al.,2022;Li RP et al.,2024),the smaller and less negatively buoyant nature of downwelling drips in stagnant lid planets are more susceptible to these effects,which leads to an ephemeral layering of the mantle.Our numerical models show that in stagnant lid planets with mantle potential temperatures that exceed 1900 K,the smaller,cold drips from the lid continue to pile up until enough of them have coalesced that they collectively avalanche as a larger instability into the deeper interior.展开更多
The Beta-Atla-Themis(BAT)region on Venus is characterized by large volcanic rises,major rift zones(chasmata),radiating,linear,and circumferential grabenfissure systems,and coronae.Its most prominent features
Pits are circular to elliptical,steep-sided,flat-bottomed depressions interpreted to form from collapse into a cavity.They occur on Earth,Venus and Mars and range in diameter from;00 m to several kilometres(e.g.
This study aims to visualize Giorgio Vasari＇s statement in discussing Jacopo Tintoretto＇s Female Concert of 1576-86, now at the Gemaldegalerie Alte Meister in Dresden （see Figure 1）. Two conceits （concetti） are ...This study aims to visualize Giorgio Vasari＇s statement in discussing Jacopo Tintoretto＇s Female Concert of 1576-86, now at the Gemaldegalerie Alte Meister in Dresden （see Figure 1）. Two conceits （concetti） are considered in analyzing Tintoretto＇s female imagery： （1） a fanciful invention of musica extravaganza; and （2） a Venetian allegory of bellezza. The first part of the essay discusses the provenance of the painting and the second part presents an iconographical interpretation of the imagery. This essay also focuses on the iconography of the painting based on viewing the subject and does not postulate on its iconography based on disappeared paintings or on a speculative decorative cycle on the theme of Hercules. Relying on well-documented research on music in Venice, on Mannerist practices, and on art theories during Tintoretto＇s life, some intriguing observations are made about the painting.展开更多
On March 1 and 5, 1982, experiments in television photography instrumented by the landers VENERA-13 and 14 returned panoramas of the Venus surface at the landing site. Over the past 31 years, no similar missions have ...On March 1 and 5, 1982, experiments in television photography instrumented by the landers VENERA-13 and 14 returned panoramas of the Venus surface at the landing site. Over the past 31 years, no similar missions have been sent to Venus. In connection with the renewed interest in what was occurring during the experiment and to the discovery of manifestations of possible life revealed on some of the pictures, the panoramas were re-examined.?Analysis of treated once again VENERA-14 panoramic images revealed a?“snake”?object about 40 cm in size possessing apparent terramorphic features. The snake’s body stands out with its honeycomb, spotty surface against the stone plates close by. The “snake”?can be included into the list of the most significant findings of the hypothetical Venusian fauna. Apart from that, of interest is a?“dove”?object, although details of its structure cannot be discerned. The snake’s body show slow movements, which is another evidence of the Venusian fauna’s very slow style of activity, which appears to be associated with its energy constraints, and that is more likely, with the properties of its internal medium. The terramorphic features of the fauna, if they are confirmed, may point out outstandingly important and yet undiscovered general laws of the animated nature.展开更多
It is possible, the question on the existence of extraterrestrial life will be answered not as a result of its search for in other worlds removed by distances of dozens of parsecs but on the surface of Venus, i.e., of...It is possible, the question on the existence of extraterrestrial life will be answered not as a result of its search for in other worlds removed by distances of dozens of parsecs but on the surface of Venus, i.e., of the nearest planet of the Solar system. The search for “habitable zones” in extrasolar planetary systems is based on the postulate on “normal” physical conditions, i.e., the pressure, temperature, and maybe atmospheric composition similar to those on Earth. But could not such an approach be a kind of “terrestrial chauvinism”? Considering the conditions on Venus as a possible analogue of physical conditions on low-orbiting exoplanets of the “super-Earths” type, a new analysis of Venusian surface panoramas’ details has been made. These images were produced by the VENERA landers in 1975 and 1982. A few relatively large objects were found with size ranging from a decimeter to half meter and with unusual morphology. The objects were observed in some images, but were absent in the other or altered their shape. The article presents the obtained results and analyzes the evidence of reality of these objects.展开更多
文摘Venusian coronae are large(60-2600 km diameter)tectono-magmatic features characterized by quasi-circular graben-fissure systems and topographic features such as a central dome,central depression,circular rim or circular
基金supported by Advanced Technique Research of Valvular Heart Disease Treatment Project(2015C03028)
文摘BACKGROUND: No retrievable and repositionable second generation transcatheter aortic valve is available in China. Here, we report the first-in-man implantation of the retrievable and repositionable VenusA-Plus valve. METHODS: A 76-year-old patient with symptomatic severe aortic stenosis and high surgical risk(STS 13.8%) was recommended for transcatheter aortic valve replacement(TAVR) by heart valve team. Type 0 bicuspid aortic valve with asymmetric calcification was identified by dual source computed tomography, and the unfavorable anatomies increased the possibility of malposition and paravalvular leakage during TAVR. Therefore, we used the retrievable and repositionable Venus APlus valve for the patient.RESULTS: Transfemoral TAVR was performed under local anesthesia with sedation, and a 26-mm VenusA-Plus valve was successfully implanted. No transvalvular pressure gradient and trace paravalvular leakage were found. CONCLUSION: The successful first-in-man implantation indicates the retrievable and repositionable Venus A-Plus valve is feasible in complicated TAVR cases such as bicuspid aortic valve.
基金Supported by the Special Fund of Chinese Central Government for Basic Scientific Research Operations in Commonweal Research Institutes titled“Eff ect of p H on the Larva Development and Carbon Sequestration of Several Intertidal Zone Bivalves in the East China Sea(Chinese Academy of Fishery Sciences)(No.2014A01YY02)the Returned Central Royalties for Using Sea Areas titled“Demonstration for Ecological Restoration and Environmental Improvement in Fengxian Sea Area Located in the Northern Seacoast of Hangzhou Bay”
文摘Aquaculture in saline-alkaline water has a major problem： microalgal blooming causes the pH of water to increase dramatically, thereby causing damage to the reared organisms. To solve this problem, we set out to find a candidate filter-feeding bivalve species suitable for saline-alkaline water to graze on microalgae and to control the pH. In the current study, we investigated the effect of carbonate alkalinity （CA, 2.5, 10.0, and 20.0 meq/L） and pH （8.0, 8.5, and 9.0） on the grazing capacity （GC） of the clam Cyclina sinensis. Additionally, the effect of clam size （small, medium, and large） and microalgae species （Nannochloropsis oculata, Chaetoceros miielleri, and lsochrysis galbana）, and the effect of bottom sediment characteristic （mud, sandy mud, and muddy sand） and thickness （3 and 6 cm） were analyzed as well. The results show that the GC on L galbana was the highest and small size had the maximum GC/W （W： wet weight including body and shells）. No significant differences were observed between sediment type and thickness. Regarding CA and pH, a significant decrease in GC by the pH or by their interaction was found. The GC ofC. sinensis was not greatly reduced in the treatments ofpH≤8.5 and CA≤20.0, and also not affected by bottom sediment type, indicating that this clam is capable to manage microalgal concentrations and might be a candidate species for pH reduction in saline-alkaline water ponds.
基金financial assistance from the Key Laboratory Project of Expressway Construction Machinery of Shaanxi Province,China(300102259510)the Key Research and Development Program of Shaanxi Province,China(2018ZDXM-GY-088)+1 种基金Analysis and compensation friction error of inclined installation feed system for NC machine tools,China(17JK0509)Study on mechanism and suppression strategy of friction error for CNC machine tools,China(2017JM5042).
文摘In recent years,more and more creatures in nature have become the source of inspiration for people to study bionic soft robots.Many such robots appear in the public’s vision.In this paper,a Venus flytrap robot similar to the biological Venus flytrap in appearance was designed and prepared.It was mainly cast by Polydimethylsiloxane(PDMs)and driven by the flexible material of Ionic Polymer Metal Composites(IPMCs).Combining with ANSYS and related experiments,the appropriate voltage and the size of IPMC were determined.The results showed that the performance of the Venus flytrap robot was the closest to the biological Venus flytrap when the size of IPMC length,width and driving voltage reach to 3 cm,1 cm and 5.5 V,respectively.Moreover,the closing speed and angle reached 8.22°/s and 37°,respectively.Finally,the fly traps also could be opened and closed repeatedly and captured a small ball with a mass of 0.3 g firmly in its middle and tip.
基金supported by NSFC grants 41904156, 41974205, 41774171, 41574173, 41774167 and 41804157the Science and Technology Development Fund of Macao SAR (008/2016/A1 and 039/2013/A2)+3 种基金the China Postdoctoral Science Foundation (2019M651271)the financial support of the Shenzhen Science and Technology Research Program (JCYJ20170811154933612 and JCYJ20180306171918617)the 111 Project (B18017)supported by CAS Center for Excellence in Comparative Planetology
文摘With Venus Express magnetic field measurements at 32 Hz from 2006 to 2012, we investigate statistically the magnetic fluctuations in the near-Venusian space. The global spatial distribution of their spectral scaling features is presented in MHD and kinetic regimes. It can be observed that turbulence is a common phenomenon in the solar wind in both regimes. The solar wind MHD turbulence is modified at the Venusian bow shock;MHD turbulence is absent in the Venusian magnetosheath but present at the magnetosheath boundary layer. Pre-existing kinetic turbulence from the far upstream solar wind is modified in the near solar wind region, while kinetic turbulence can be extensively observed throughout the Venusian magnetosheath and in some regions of the induced magnetosphere. Our results reveal that, in the near-Venusian space, energy cascade can be developed at the boundary between magnetosheath and wake, and the turbulence-related dissipation of magnetic energy occurs extensively in the magnetosheath and the induced magnetosphere.
基金I want to express my gratitude to the auction houses,libraries,museums,photographic collections(Wikipedia,Wiki Commons Images),and private collections here cited for their assistance in granting me permission to photograph or reproduce the images in this essay.
文摘The Pre-Raphaelite painter Edward Burne-Jones(1833-1898)conceived the subject of The Mirror of Venus between 1865 and 1867.He painted two versions:a small version in gouache and oil and a larger version in oil on canvas.In composing this subject Burne-Jones was inspired by the poetic and chromatic description of a lyrical stanza on“The Hill of Venus”in the long epic poem Earthly Paradise,written by his close friend and collaborator William Morris.1 This study comprises three parts:Burne-Jones’s history of the paintings,his iconographical sources,and an iconological interpretation of The Mirror of Venus.
基金supported by the National Natural Science Foundation of China (41525016, 41525015, 41661164034, 41621063)the National Important Basic Research Project (2011CB811405)supported by the Thousand Young Talents Program of China
文摘The Venusian dayside ionosphere, similar to other planetary ionospheres, is produced primarily by ionization of its neutral upper atmosphere due to solar extreme ultraviolet (EUV) radiation. It has become clear that the expansion of the ionosphere may be strongly controlled by the EUV level, as exhibited in data collected by the Pioneer Venus Orbiter (PVO) during one solar cycle (1978 1992). However, the EUV-dependence of the Venusian dayside ionopause altitude, which defines the outer boundary of the ionosphere, remains obscure because the PVO crossed the dayside ionopause only during the solar maximum;its periapsis lifted too high during the solar minimum. Recently, during the period 2006 2014, which included the longest and quietest solar minimum of the past several decades, Venus Express (VEX) provided measurements of the photoelectron boundary (PEB) over the northern high-latitude region. Since the photoelectron boundary is closely related to the ionopause, we have an opportunity to analyze the EUV effect on the dayside ionopause by combining PVO and VEX observations. We have evaluated and then reduced the orbit bias effect in data from both PVO and VEX, and then used the results to derive a relationship between solar EUV level and the dayside ionopause altitude. We find that the dayside ionopause altitude increases as the solar EUV level increases, which is consistent with theoretical expectations.
基金This paper was supported by European Space Agency(ESA)contract 4000121195-Ministry of Science and Technology(MOST),Dragon 4 cooperation(ID:32275).Specifically,Subproject1-Topic1“Algorithm Development Exploiting Multitemporal and Multi Sensor Satellite Data for Improving Crop Classification,Biophysical and Agronomic Variables Retrieval and Yield Prediction”and by the Italian Space Agency(ASI)project PRISCAV(PRISMA Calibration/Validation).
文摘This paper is devoted to the development and testing of the optimal procedures for retrieving biophysical crop variables by exploiting the spectral information of current multispectral optical satellite Sentinel-2 and Venus and in view of the advent of the new Sino-EU hyperspectral satellite(e.g.,PRISMA,EnMAP,and GF-5).Two different methodologies devoted to the estimation of biophysical crop variables Leaf area index(LAI)and Leaf chlorophyll content(Cab)were evaluated:non-kernel-based and kernel-based Machine Learning Regression Algorithms(MLRA);Sentinel-2 and Venus data comparison for the analysis of the durum wheat-growing season.Results show that for Sentinel-2 data,Gaussian Process Regression(GPR)was the best performing algorithm for both LAI(R 2=0.89 and RMSE=0.59)and Cab(R 2=0.70 and RMSE=8.31).Whereas,for PRISMA simulated data the Kernel Ridge Regression(KRR)was the best performing algorithm among all the other MLRA(R 2=0.91 and RMSE=0.51)for LAI and(R 2=0.83 and RMSE=6.09)for Cab,respectively.Results of Sentinel-2 and Venus data for durum wheat-growing season were consistent with ground truth data and confirm also that SWIR bands,which are used as tie-points in the PROSAIL inversion,are extremely useful for an accurate retrieving of crop biophysical parameters.
基金supported by the National Natural Science Foundation of China[Grant no.52005355]Postdoctoral Science Foundation of China[Grant no.2020M671575]+2 种基金Opening Project of the Key Laboratory of Bionic Engineering(Ministry of Education),Jilin University[Grant no.KF20200004]Opening Project of the Key Laboratory of Advanced Robotics of Jiangsu Provience[Grant no.JAR201901]Natural Natural Science Research Project of Higher Education of Jiangsu Province[Grant no.20KJB460007].
文摘Venus flytrap can sense the very small insects that touch its tactile receptors,known as trigger hairs,and thus capture prey to maintain its nutrient demand.However,there are few studies on the trigger hair and its morphological structure and material properties are not fully understood.In this study,the trigger hair is systematically characterized with the help of diff erent instruments.Results show that trigger hair is a special cantilever beam structure and it has a large longitudinal diameter ratio.Besides,it is composed of a hair lever and a basal podium,and there is a notch near the hair base.The crosssection of the trigger hair is approximately a honeycomb structure,which is composed of many holes.Methods to measure mechanical properties of trigger hair are introduced in this paper.Based on the mechanical tests,trigger hair proved to be a variable stiff ness structure and shows a high sensitivity to the external force.These features can provide supports for the understanding of the high-sensitivity sensing mechanism of trigger hairs from the perspective of structure and material,and off er inspirations for the development of high-performance tactile sensors.
基金The authors are thankful for support from NASA Award 80NSSC22K0100U.S.Department of Energy Computational Science Graduate Fellowship under Award Number DESC0022158+1 种基金Computational resources were provided by Extreme Science and Engineering Discovery Environment(XSEDE),which is supported by National Science Foundation grant number ACI-1053575This research used resources of the National Energy Research Scientific Computing Center(NERSC),a Department of Energy Office of Science User Facility using NERSC award ASCRERCAP0026889.
文摘Stagnant lid planets are characterized by a globe-encircling,conducting lid that is thick and strong,which leads to reduced global surface heat flows.Consequently,the mantles of such planets can have warmer interiors than Earth,and interestingly,a pyrolitic mantle composition under warmer conditions is predicted to have a distinctly different mantle transition zone compared to the present-day Earth(Hirose,2002;Stixrude and Lithgow-Bertelloni,2011;Ichikawa et al.,2014;Dannberg et al,2022).Instead of olivine primarily transforming into its higher-pressure polymorphs such as wadsleyite and then ringwoodite,at pressures corresponding to 410 km and 520 km depth in Earth,respectively,it instead transforms into a mineral assemblage of wadsleyite,majorite,and ferropericlase(WMF),and then to majorite+ferropericlase(MF),before finally transforming into bridgmanite at pressures corresponding to 660 km depth in Earth(Stixrude and Lithgow-Bertelloni,2011;Ichikawa et al.,2014).Convective motions in stagnant lid planets are dominated by small-scale instabilities(cold drips)forming within the mobile rheological sublayer under the rigid lid.Using ASPECT and a thermodynamic model of a pyrolitic mantle composition generated by HeFESTo,we show that under certain conditions,the small drips can pond atop the WMF-MF mineral phase transition.The barrier to convective flow arises from the WMF mineral phase assemblage having an effective negative thermal expansivity(Stixrude and Lithgow-Bertelloni,2022).Although large-scale downwellings that typically occur within mobile lid planets are able to pass through the WMF zone without difficulty(Dannberg et al.,2022;Li RP et al.,2024),the smaller and less negatively buoyant nature of downwelling drips in stagnant lid planets are more susceptible to these effects,which leads to an ephemeral layering of the mantle.Our numerical models show that in stagnant lid planets with mantle potential temperatures that exceed 1900 K,the smaller,cold drips from the lid continue to pile up until enough of them have coalesced that they collectively avalanche as a larger instability into the deeper interior.
文摘The Beta-Atla-Themis(BAT)region on Venus is characterized by large volcanic rises,major rift zones(chasmata),radiating,linear,and circumferential grabenfissure systems,and coronae.Its most prominent features
文摘Pits are circular to elliptical,steep-sided,flat-bottomed depressions interpreted to form from collapse into a cavity.They occur on Earth,Venus and Mars and range in diameter from;00 m to several kilometres(e.g.
文摘This study aims to visualize Giorgio Vasari＇s statement in discussing Jacopo Tintoretto＇s Female Concert of 1576-86, now at the Gemaldegalerie Alte Meister in Dresden （see Figure 1）. Two conceits （concetti） are considered in analyzing Tintoretto＇s female imagery： （1） a fanciful invention of musica extravaganza; and （2） a Venetian allegory of bellezza. The first part of the essay discusses the provenance of the painting and the second part presents an iconographical interpretation of the imagery. This essay also focuses on the iconography of the painting based on viewing the subject and does not postulate on its iconography based on disappeared paintings or on a speculative decorative cycle on the theme of Hercules. Relying on well-documented research on music in Venice, on Mannerist practices, and on art theories during Tintoretto＇s life, some intriguing observations are made about the painting.
文摘On March 1 and 5, 1982, experiments in television photography instrumented by the landers VENERA-13 and 14 returned panoramas of the Venus surface at the landing site. Over the past 31 years, no similar missions have been sent to Venus. In connection with the renewed interest in what was occurring during the experiment and to the discovery of manifestations of possible life revealed on some of the pictures, the panoramas were re-examined.?Analysis of treated once again VENERA-14 panoramic images revealed a?“snake”?object about 40 cm in size possessing apparent terramorphic features. The snake’s body stands out with its honeycomb, spotty surface against the stone plates close by. The “snake”?can be included into the list of the most significant findings of the hypothetical Venusian fauna. Apart from that, of interest is a?“dove”?object, although details of its structure cannot be discerned. The snake’s body show slow movements, which is another evidence of the Venusian fauna’s very slow style of activity, which appears to be associated with its energy constraints, and that is more likely, with the properties of its internal medium. The terramorphic features of the fauna, if they are confirmed, may point out outstandingly important and yet undiscovered general laws of the animated nature.
文摘It is possible, the question on the existence of extraterrestrial life will be answered not as a result of its search for in other worlds removed by distances of dozens of parsecs but on the surface of Venus, i.e., of the nearest planet of the Solar system. The search for “habitable zones” in extrasolar planetary systems is based on the postulate on “normal” physical conditions, i.e., the pressure, temperature, and maybe atmospheric composition similar to those on Earth. But could not such an approach be a kind of “terrestrial chauvinism”? Considering the conditions on Venus as a possible analogue of physical conditions on low-orbiting exoplanets of the “super-Earths” type, a new analysis of Venusian surface panoramas’ details has been made. These images were produced by the VENERA landers in 1975 and 1982. A few relatively large objects were found with size ranging from a decimeter to half meter and with unusual morphology. The objects were observed in some images, but were absent in the other or altered their shape. The article presents the obtained results and analyzes the evidence of reality of these objects.
