Even the sulfur cathode in lithium-sulfur(Li-S)battery has the advantages of high theoretical energy density,wide source of raw materials,no pollution to the environment,and so on.It still suffers the sore points of e...Even the sulfur cathode in lithium-sulfur(Li-S)battery has the advantages of high theoretical energy density,wide source of raw materials,no pollution to the environment,and so on.It still suffers the sore points of easy electrode collapse due to large volume expansion during charge and discharge and low active materials utilization caused by the severe shuttle effect of lithium polysulfides(LiPSs).Therefore,in this work,ramie gum(RG)was extracted from ramie fiber degumming liquid and used as the functional binder to address the above problems and improve the Li-S battery’s performance for the first time.Surprisingly,the sulfur cathode using RG binder illustrates a high initial capacity of 1152.2 mAh/g,and a reversible capacity of 644.6 mAh/g after 500 cycles at 0.5 C,far better than the sulfur cathode using polyvinylidene fluoride(PVDF)and sodium carboxymethyl cellulose(CMC)binder.More importantly,even if the active materials loading increased to as high as 4.30 mg/cm^(2),the area capacity is still around 3.1 mAh/cm^(2)after 200 cycles.Such excellent performances could be attributed to the abundant oxygen-and nitrogen-containing functional groups of RG that can effectively inhibit the shuttle effect of LiPSs,as well as the excellent viscosity and mechanical properties that can maintain electrode integrity during long-term charging/discharging.This work verifies the feasibility of RG as an eco-friendly and high-performance Li-S battery binder and provides a new idea for the utilization of agricultural biomass resources.展开更多
From a very early period,the Chinese already vaguely sensed that the cultivation of crops required an intricate system.The third century BCE work Master Lü’s Spring and Autumn Annals(Lüshi chunqiu吕氏春秋)s...From a very early period,the Chinese already vaguely sensed that the cultivation of crops required an intricate system.The third century BCE work Master Lü’s Spring and Autumn Annals(Lüshi chunqiu吕氏春秋)states that crops were fed by heaven and raised by earth,and that harvests depended on the farmers who worked the land.Therefore,these three elements,that is,heaven,earth,and farmers,together with crops,jointly constituted a complex community.According to the ancient Chinese,moving a crop away from its native place could bring huge benefits to the new area to which the crop was moved.When writing and compiling Fundamentals of Agriculture and Sericulture(Nongsang jiyao农桑辑要),the officials of the Agricultural Extension Bureau司农司in the Yuan dynasty(1271–1368)excitedly noted the changes brought about by non-native crops to the agriculture of the Central Plains of China中原:“Ramie(Boehmeria nivea)is a crop native to southern China,while cotton(Gossypium herbaceum)comes from the Western Regions西域.In recent years,nevertheless,ramie has been introduced to Henan,while cotton has started to be planted in Shaanxi.The two crops thrive and show no difference from local crops.Farmers in the two regions benefit a lot therefrom”(Agricultural Extension Bureau 1888,juan 2:21).展开更多
[Objective] The aim was to study on in-situ elimination effect on heavy metals in soil of the mining area by ramie （Boehmeria nivea （L.） Gaud.）. [Methods] Based on Xiangzhu No.3 and Zhongzhu No.1, we conducted res...[Objective] The aim was to study on in-situ elimination effect on heavy metals in soil of the mining area by ramie （Boehmeria nivea （L.） Gaud.）. [Methods] Based on Xiangzhu No.3 and Zhongzhu No.1, we conducted research on heavy metals contents of plants growing in soil of Qibao Mountain orefield in Liuyang, Hunan Province, and on characteristics of enrichment and transfer of heavy metals （Cu, Pb, Cd, Zn） under influence of the two ramie species. [Result] It was concluded that trend of Cu content in different parts of ramie was as follows： rootskinleafbone; trend of Pb was rootleafskinbone; trend of Cd was rootskinboneleaf; the trend of Zn was rootskinboneleaf. In farmland A （with low content of heavy metal）, for per square meter of plough horizon, effect of Zhong 1 on heavy metals transferring volume and the period for restoration of the soil into national standard one （Category Ⅲ of Environmental Quality Standard for Soil） have been concluded. Specifically, for Cu, the corresponding values were 3 404.44 mg and 8.59 y, respectively; for Pb, the values were 3 638.5 mg and 13.52 y; for Cd, the values were 720.48 mg and 1.49 y; for Zn, the values were 37 324.8 mg and 0.67 y. [Conclusion] Soil contaminated by Cu, Pb, Cd, and Zn in orefield can be rapidly restored by growing ramie.展开更多
[Objective] This study was to investigate the climatic factors affecting the regional eco-adaptability of ramie.[Method] Five experimental sites of different eco-types in ramie growing regions in Yangtze Valley were s...[Objective] This study was to investigate the climatic factors affecting the regional eco-adaptability of ramie.[Method] Five experimental sites of different eco-types in ramie growing regions in Yangtze Valley were set up to investigate the yield of Zhongzhu No.2,based on which we assessed the adaptability of Zhongzhu No.2 to various eco-regions and further analyzed the climatic factors causing the difference in eco-adaptability.[Result] Ramie yield varied largely among various experimental sites and the yield difference appeared to be well repeatable,with a differential value between the maximum and the minimum reaching 2.3 kg/20 m2.Analysis of the yield data,together with climatic factors in various ecological regions showed that yield of Zhongzhu No.2 was significantly correlated with rainfall,sunshine hours,relative humidity during its growing period.Of the climatic factors,sunshine hours and rainfall can positively promote yield increase,while relative humidity negatively regulate ramie yield.[Conclusion] The climatic indices,including rainfall,sunshine duration and relative humidity are a key factor causing yield difference in ramie among different regions of Yangtze Valley.展开更多
Haptic feedback is typically missing during telemanipulation of surgical robots in minimally invasive surgeries,i.e.,surgeons cannot feel the interaction forces between the instruments and tissues.Instead,surgeons hav...Haptic feedback is typically missing during telemanipulation of surgical robots in minimally invasive surgeries,i.e.,surgeons cannot feel the interaction forces between the instruments and tissues.Instead,surgeons have to solely rely on visual feedback,which increases complexity of guiding the instruments and poses the safety threat of unperceivable contacts outside the field of view.We propose a novel series elastic actuation design for articulated robotic endoscopes to overcome these limitations and evaluate an according device with one joint.Similar to the actuation of human fingers,the joint is driven by antagonistic tendons.Springs are integrated in the transmission between the tendons and the motors outside of the endoscope shaft.We estimated the joint angle and thereby the endoscope shape,measured spring deflection,estimated tendon forces from that deflection,and implemented force control for the endoscope joint.Zero torque control and impedance control were evaluated under application of both a continuous force and an impact force to the endoscope tip.The springs reduced impact forces at the tip of the endoscope through their inherent compliance.At the same time,feeding back the estimated force resulted in a stable tendon force control and a tunable endoscope joint control:Zero torque control effectively reduced the external forces,while the endoscope joint showed the expected stiffness in impedance control.These results show that antagonistic series elastic actuation is a promising concept for endoscope joint actuation and that it can lead towards safer robot–tissue interactions in surgical robotics.展开更多
The protective role of exogenously supplied selenium （Se^6＋） on Bechmeria nivea （L.） Gaud （Ramie） subjected to cadmium （Cd） stress was studied in vitro, and the mechanism was discussed by investigating plant ...The protective role of exogenously supplied selenium （Se^6＋） on Bechmeria nivea （L.） Gaud （Ramie） subjected to cadmium （Cd） stress was studied in vitro, and the mechanism was discussed by investigating plant growth, malondialdehyde （MDA）, activity of antioxidative enzymes and DNA methylation pattern. Plants grown in hydroponic culture were supplied with spraying Se （selenate, 1.2μmol/L） and cadmium （Cd（NO3）2, 0, 3, 6 and 9 mg/L）, individually or simultaneously. At low Se spraying levels, SOD activity was increased by 35.34%, 43.18%, 3.63%under 3, 6 or 9 mg/L cadmium contents, POD was increased by 12.45%, 14.14%, 3.27%, and the level of DNA methylation was decreased by 10.70%, 18.18%and 15.59%, respectively. The results confirmed that spraying low Se on ramie leaves could enhance the activity of SOD and POD, and regulate DNA methylation in ramie leaves.展开更多
The objective of this article is to reveal the variations of ramie inbred lines in DNA level and discuss their molecular background to provide a theoretical basis for ramie cross breeding. In the present study, the ge...The objective of this article is to reveal the variations of ramie inbred lines in DNA level and discuss their molecular background to provide a theoretical basis for ramie cross breeding. In the present study, the genetic relationships among 33 inbred line accessions and two wild types that originated from China and Brazil were estimated using sequence-related amplified polymorphism （SRAP） markers. The results showed that 33 out of 81 primer combinations turned out to be polymorphic and 332 polymorphism bands were obtained. On the basis of the appearance of the markers, the genetic relationships were analyzed using unweighted pair-group method of arithmetic average cluster analysis （UPGMA）, and the genetic Jaccard similarity coefficients were calculated. The inbred-lines originating from China and Brazil formed a cluster suggesting a possibility that the Brazilian cultivars could have developed from cultivars introduced from China. Within ramie inbred-lines, the groupings also indicated that the greatest genetic relationship among cultivars was correlated to the region of origin of cultivars. The results provided the evidence that SRAP was an efficient approach, suitable for taxonomic analysis of ramie inbred lines, To the authors＇ knowledge, this is the first application of SRAP marker on the systematics of ramie inbred lines.展开更多
To enhance the bonding properties between ramie fiber and epoxy resin,the ramie fiber was modified using nano-silica grafting.Hydrophilic nano-silica treated with water-soluble sodium dodecyl sulfate(SDS)and organic s...To enhance the bonding properties between ramie fiber and epoxy resin,the ramie fiber was modified using nano-silica grafting.Hydrophilic nano-silica treated with water-soluble sodium dodecyl sulfate(SDS)and organic silane coupling agents was grafted onto the surface of ramie fiber.The surface roughness of the fibers was considerably increased after grafting.The nano-silica particles on the fiber surface enhanced the mechanical and thermal properties of the fiber-epoxy composite plates.Based on an analysis of contact angle measurements and a water absorption study,it was determined that the hydrophilicity of the treated fiber was weakened.展开更多
In order to verify the possible use of ramie as feed for ruminants, a study was undertaken on the chemical and nutritional evaluation of different parts of this plant. Four stocks of samples picked up in two different...In order to verify the possible use of ramie as feed for ruminants, a study was undertaken on the chemical and nutritional evaluation of different parts of this plant. Four stocks of samples picked up in two different periods （summer and autumn） were analyzed. The standard chemical composition was determined on the whole plant and on its parts, the study was particularly focused on leaves and tops, not used in fibre production and available as livestock feed. Organic matter enzymic digestibility （OMD） was determined on all the samples by a double step method based on cellnlolytic andproteolytic enzymes. The chemical analysis showed good crude proteins content in leaves, tops and whole plant： 17.00 ~ 1.52%, 15.25 ~ 0.77% and 11.79 ~ 3.32% on dry matter （DM） basis respectively and good acid （ADF） and neutral （NDF） detergent fibre fractions. Lignin and ash resulted high in all plant parts and organic matter （OM） was consequently low, ash analysis showed high calcium concentration, especially in leaves, with values exceeding 4% of din, whereas the other micro （except the lead） and macroelements were in a normal range. OMD and energy values resulted poor in leaves, tops and in the whole plant and lower than the other forages commonly used as feed for runninants, thus the utilisation of ramie plant and its by-products requests further investigations.展开更多
As the most important cultural practices for ramie （Boehmeria nivea） production, the single effects of plant density and nitrogen （N）, phosphorus （P）, potassium （K） fertilization on yield are well documented. ...As the most important cultural practices for ramie （Boehmeria nivea） production, the single effects of plant density and nitrogen （N）, phosphorus （P）, potassium （K） fertilization on yield are well documented. To achieve the high yield and quality of ramie fiber, it is principal to quantify the fertilizer dosage for ramie sustainable production. A central composite design （CCD） was adopted with three replications, for a two-year field experiment （2008-2009） in the Yangtze River Valley of China. The aim was to evaluate both the individual and combined effects of plant density and N, P, and K fertilization on yield and fiber quality. The effects of the four factors on yield and quality of ramie cultivar Huazhu 4 were tested. Then mathematical models of the relationship among the four factors affecting ramie production and quality were established and analyzed to optimize the four factors, and used to establish optimum cultivation methods for the elite cultivar suitable to this area of the Yangtze River Valley. Supplements of N （X2）, P 0（3） and K 0（4）, and the density （X0 with N （X2） interaction significantly influenced strength in tests of mature ramie. The influence on fiber yield in the two year tests by the four factors ranked as follows： X3〉X4〉X~〉X2. We established the optimization technique attaining yield of 2 600 kg ha-~ in the tests as following： density of 28 350-31 650 plants ha-1, and supplements of N, P and K of 363-387, 98.58-105.48 and 280.20- 319.8 kg ha-1, respectively. It was concluded that nitrogen mostly improved plant growth and fiber yield while potassium had discernible effects on fiber quality.展开更多
The natural fiber/poly(lactic acid) (PLA) composites were prepared with ramie and jute short fiber as reinforcement and PLA as matrix. The mechanical and thermal properties of the composites were investigated. The res...The natural fiber/poly(lactic acid) (PLA) composites were prepared with ramie and jute short fiber as reinforcement and PLA as matrix. The mechanical and thermal properties of the composites were investigated. The results show that the properties of the composites are better than those of plain PLA. When the content of the fiber is 30%, the composites can get the best mechanical properties. The dynamic mechanical analysis results show that the storage moduli of the PLA/ramie and PLA/jute composites increase with respect to the plain PLA. The Vicat softening temperature of the composites is greatly higher than that of PLA. The results of thermogravimetric analysis show that adding fiber to the PLA matrix can improve the degradation temperature of PLA.展开更多
With the increasing awareness of environmental protection and rational utilization of resources,natural fiber reinforced composites have shown broad development prospects.Apocynum fiber,known as the“king of wild fibe...With the increasing awareness of environmental protection and rational utilization of resources,natural fiber reinforced composites have shown broad development prospects.Apocynum fiber,known as the“king of wild fiber”,not only has moisture absorption,air permeability,and good mechanical properties but also has many health-related advantages such as antibacterial properties.In this study,four types of needle-punched Apocynum fiber and ramie fiber mat reinforced polylactic acid(PLA)composites were fabricated.Mechanical and thermal properties of the composites were tested and analyzed.The results showed that compared with those of the ramie fiber finish needle-punched mat reinforced composites,the tensile strength and the tensile modulus of Apocynum fiber finish needle-punched mat reinforced composites had increased by 15.3%and 60.1%,respectively.In comparison,the bending strength and the bending modulus were decreased by 21.8%and 7.6%,respectively.Moreover,compared with the Apocynum fiber finish needled-punched mat reinforced composites and the ramie fiber finish needle-punched mat reinforced composites,the Apocynum 50/ramie 50 finish needle-punched mat reinforced composites had the best tensile and bending properties.The after-fracture morphology was detected by a scanning electron microscope(SEM).The thermal properties of the composites were also characterized.It was found that the thermal properties of the four types of composites showed very similar behaviors.展开更多
To explore the role of ethylene in sexual determination in ramie, the ethylene release rates in ramie stem apex of different sex, bud of the same node in female and hermaphrodite ramie in the second crop, and single i...To explore the role of ethylene in sexual determination in ramie, the ethylene release rates in ramie stem apex of different sex, bud of the same node in female and hermaphrodite ramie in the second crop, and single inflorescence of different sex in hermaphrodite ramie were measured by gas chromatography. Effects of two ethylene inhibitors on sex expression in ramie were investigated. The ethylene release rate of stem apex was higher in the second crop or female ramie than that in the third crop or hermaphrodite ramie during growth. Although ethylene release rates between lower nodes and higher nodes were little different, it was lower in the middle nodes in hermaphrodite ramie. The ethylene release rates were higher in the higher nodes of female ramie at the second crop. At the third crop, the ethylene release rates were higher in lower nodes, lower in middle nodes and then highest in higher nodes in female ramie. However, an opposite ethylene release pattern was observed in hermaphrodite ramie. The ethylene release rate was higher in female flower than male flower and mixed inflorescence in hermaphrodite ramie. The male flower could be distinctly induced by AVG （aminooethoxyvinylglycine）. The node of the first male flower, percentage of female flowers and ratio of female flowers to male in ramie were evidently depressed by AVG in contrast to water. The percentage of mixed male and female flowers was also increased and the percentage of female flower decreased by spraying AgNO3. There was a close relationship between sexual differentiation and ethylene release rate in ramie. The female ramie could be induced by high ethylene release rate. The female flower could be inhibited by AVG and AgNO3. AVG at a concentration of 300 mg L^-1 was most effective.展开更多
Ramie (Boehmeria nivea L.) is one of the most important fiber crops and biomass materials. However, previous studies showed that ramie presented a very low nitrogen agronomy efficiency (NAE, 23.2%~27.8%) in traditiona...Ramie (Boehmeria nivea L.) is one of the most important fiber crops and biomass materials. However, previous studies showed that ramie presented a very low nitrogen agronomy efficiency (NAE, 23.2%~27.8%) in traditional farming, and the nitrogen fertilizer was applied excessively in ramie field. Plant osmotic adjustment (OA) responses to environmental stresses positively and exhibits improvements in plant tolerance. Whereas results varied due to the complexity of plant-environment interactions and lack of insights of specific species. In order to improve ramie production through osmoregulation, our current study investigated the role of nitrogen application and osmotic adjustment in improving the growth and yield in two varieties of ramie (H2000-03 and Ceheng Jiama) with contrasting nitrogen use efficiency (NUE) grown at 5 different N rates including N0, N6, N9, N12 and N15;0, 6, 9, 12 and 15 mmol/L N, respectively. The results showed that ramie adapted to different nitrogen rates through OA and significant differences of osmolyte content between varieties only presented at the particular growth stage. Obvious inflexion of yield, osmolyte content involving proline, soluble protein (SP), soluble sugar (SS) and malonaldehyde (MDA);nitrogen sensitive index (NSI) and comprehensive evaluation (D) in both varieties were observed. Our results recommended that the overall lifting of OA at a lower N level and at the proper growth stage would be a reasonable approach for improving ramie NUE.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51902036,52071295,52002352)Natural Science Foundation of Chongqing Science&Technology Commission(Nos.cstc2019jcyj-msxm1407 and CSTB2022NSCQ-MSX0828)+2 种基金the Venture&Innovation Support Program for Chongqing Overseas Returnees(No.CX2021046)the Science and Technology Research Program of Chongqing Municipal Education Commission(No.KJZDK202300802)Research Project of Innovative Talent Training Engineering Program of Chongqing Primary and Secondary School(No.CY230801).
文摘Even the sulfur cathode in lithium-sulfur(Li-S)battery has the advantages of high theoretical energy density,wide source of raw materials,no pollution to the environment,and so on.It still suffers the sore points of easy electrode collapse due to large volume expansion during charge and discharge and low active materials utilization caused by the severe shuttle effect of lithium polysulfides(LiPSs).Therefore,in this work,ramie gum(RG)was extracted from ramie fiber degumming liquid and used as the functional binder to address the above problems and improve the Li-S battery’s performance for the first time.Surprisingly,the sulfur cathode using RG binder illustrates a high initial capacity of 1152.2 mAh/g,and a reversible capacity of 644.6 mAh/g after 500 cycles at 0.5 C,far better than the sulfur cathode using polyvinylidene fluoride(PVDF)and sodium carboxymethyl cellulose(CMC)binder.More importantly,even if the active materials loading increased to as high as 4.30 mg/cm^(2),the area capacity is still around 3.1 mAh/cm^(2)after 200 cycles.Such excellent performances could be attributed to the abundant oxygen-and nitrogen-containing functional groups of RG that can effectively inhibit the shuttle effect of LiPSs,as well as the excellent viscosity and mechanical properties that can maintain electrode integrity during long-term charging/discharging.This work verifies the feasibility of RG as an eco-friendly and high-performance Li-S battery binder and provides a new idea for the utilization of agricultural biomass resources.
文摘From a very early period,the Chinese already vaguely sensed that the cultivation of crops required an intricate system.The third century BCE work Master Lü’s Spring and Autumn Annals(Lüshi chunqiu吕氏春秋)states that crops were fed by heaven and raised by earth,and that harvests depended on the farmers who worked the land.Therefore,these three elements,that is,heaven,earth,and farmers,together with crops,jointly constituted a complex community.According to the ancient Chinese,moving a crop away from its native place could bring huge benefits to the new area to which the crop was moved.When writing and compiling Fundamentals of Agriculture and Sericulture(Nongsang jiyao农桑辑要),the officials of the Agricultural Extension Bureau司农司in the Yuan dynasty(1271–1368)excitedly noted the changes brought about by non-native crops to the agriculture of the Central Plains of China中原:“Ramie(Boehmeria nivea)is a crop native to southern China,while cotton(Gossypium herbaceum)comes from the Western Regions西域.In recent years,nevertheless,ramie has been introduced to Henan,while cotton has started to be planted in Shaanxi.The two crops thrive and show no difference from local crops.Farmers in the two regions benefit a lot therefrom”(Agricultural Extension Bureau 1888,juan 2:21).
基金Supported by National Programs for High Technology Research and Development of China(2007AA061001)Talent Introduction Project Supported by Hunan Agricultural University Project(07YT03)~~
文摘[Objective] The aim was to study on in-situ elimination effect on heavy metals in soil of the mining area by ramie （Boehmeria nivea （L.） Gaud.）. [Methods] Based on Xiangzhu No.3 and Zhongzhu No.1, we conducted research on heavy metals contents of plants growing in soil of Qibao Mountain orefield in Liuyang, Hunan Province, and on characteristics of enrichment and transfer of heavy metals （Cu, Pb, Cd, Zn） under influence of the two ramie species. [Result] It was concluded that trend of Cu content in different parts of ramie was as follows： rootskinleafbone; trend of Pb was rootleafskinbone; trend of Cd was rootskinboneleaf; the trend of Zn was rootskinboneleaf. In farmland A （with low content of heavy metal）, for per square meter of plough horizon, effect of Zhong 1 on heavy metals transferring volume and the period for restoration of the soil into national standard one （Category Ⅲ of Environmental Quality Standard for Soil） have been concluded. Specifically, for Cu, the corresponding values were 3 404.44 mg and 8.59 y, respectively; for Pb, the values were 3 638.5 mg and 13.52 y; for Cd, the values were 720.48 mg and 1.49 y; for Zn, the values were 37 324.8 mg and 0.67 y. [Conclusion] Soil contaminated by Cu, Pb, Cd, and Zn in orefield can be rapidly restored by growing ramie.
基金Supported by Modern Agricultural Industry Technology System(nycytx-19-E16)Natural Science Foundation of Hunan Province(10JJ3063)~~
文摘[Objective] This study was to investigate the climatic factors affecting the regional eco-adaptability of ramie.[Method] Five experimental sites of different eco-types in ramie growing regions in Yangtze Valley were set up to investigate the yield of Zhongzhu No.2,based on which we assessed the adaptability of Zhongzhu No.2 to various eco-regions and further analyzed the climatic factors causing the difference in eco-adaptability.[Result] Ramie yield varied largely among various experimental sites and the yield difference appeared to be well repeatable,with a differential value between the maximum and the minimum reaching 2.3 kg/20 m2.Analysis of the yield data,together with climatic factors in various ecological regions showed that yield of Zhongzhu No.2 was significantly correlated with rainfall,sunshine hours,relative humidity during its growing period.Of the climatic factors,sunshine hours and rainfall can positively promote yield increase,while relative humidity negatively regulate ramie yield.[Conclusion] The climatic indices,including rainfall,sunshine duration and relative humidity are a key factor causing yield difference in ramie among different regions of Yangtze Valley.
基金the generous funding by the Werner Siemens Foundation.
文摘Haptic feedback is typically missing during telemanipulation of surgical robots in minimally invasive surgeries,i.e.,surgeons cannot feel the interaction forces between the instruments and tissues.Instead,surgeons have to solely rely on visual feedback,which increases complexity of guiding the instruments and poses the safety threat of unperceivable contacts outside the field of view.We propose a novel series elastic actuation design for articulated robotic endoscopes to overcome these limitations and evaluate an according device with one joint.Similar to the actuation of human fingers,the joint is driven by antagonistic tendons.Springs are integrated in the transmission between the tendons and the motors outside of the endoscope shaft.We estimated the joint angle and thereby the endoscope shape,measured spring deflection,estimated tendon forces from that deflection,and implemented force control for the endoscope joint.Zero torque control and impedance control were evaluated under application of both a continuous force and an impact force to the endoscope tip.The springs reduced impact forces at the tip of the endoscope through their inherent compliance.At the same time,feeding back the estimated force resulted in a stable tendon force control and a tunable endoscope joint control:Zero torque control effectively reduced the external forces,while the endoscope joint showed the expected stiffness in impedance control.These results show that antagonistic series elastic actuation is a promising concept for endoscope joint actuation and that it can lead towards safer robot–tissue interactions in surgical robotics.
基金Project(41271332)supported by the National Natural Science Foundation of ChinaProject(11JJ2031)supported by the Natural Science Foundation of Hunan Province,China
文摘The protective role of exogenously supplied selenium （Se^6＋） on Bechmeria nivea （L.） Gaud （Ramie） subjected to cadmium （Cd） stress was studied in vitro, and the mechanism was discussed by investigating plant growth, malondialdehyde （MDA）, activity of antioxidative enzymes and DNA methylation pattern. Plants grown in hydroponic culture were supplied with spraying Se （selenate, 1.2μmol/L） and cadmium （Cd（NO3）2, 0, 3, 6 and 9 mg/L）, individually or simultaneously. At low Se spraying levels, SOD activity was increased by 35.34%, 43.18%, 3.63%under 3, 6 or 9 mg/L cadmium contents, POD was increased by 12.45%, 14.14%, 3.27%, and the level of DNA methylation was decreased by 10.70%, 18.18%and 15.59%, respectively. The results confirmed that spraying low Se on ramie leaves could enhance the activity of SOD and POD, and regulate DNA methylation in ramie leaves.
基金the National High Technology Research and Development Program of China(2001AA241121)948 Project of the Ministry of Agriculture of China(2006-G18(03))the Key Technology R&D Program of Hubei Province,China(2007AA201C49)
文摘The objective of this article is to reveal the variations of ramie inbred lines in DNA level and discuss their molecular background to provide a theoretical basis for ramie cross breeding. In the present study, the genetic relationships among 33 inbred line accessions and two wild types that originated from China and Brazil were estimated using sequence-related amplified polymorphism （SRAP） markers. The results showed that 33 out of 81 primer combinations turned out to be polymorphic and 332 polymorphism bands were obtained. On the basis of the appearance of the markers, the genetic relationships were analyzed using unweighted pair-group method of arithmetic average cluster analysis （UPGMA）, and the genetic Jaccard similarity coefficients were calculated. The inbred-lines originating from China and Brazil formed a cluster suggesting a possibility that the Brazilian cultivars could have developed from cultivars introduced from China. Within ramie inbred-lines, the groupings also indicated that the greatest genetic relationship among cultivars was correlated to the region of origin of cultivars. The results provided the evidence that SRAP was an efficient approach, suitable for taxonomic analysis of ramie inbred lines, To the authors＇ knowledge, this is the first application of SRAP marker on the systematics of ramie inbred lines.
基金supported by the Chinese MIIT Special Research Plan on Civil Aircraft(No.MJ-2015-H-G-103)the National Natural Science Foundation of China(No.51878223)
文摘To enhance the bonding properties between ramie fiber and epoxy resin,the ramie fiber was modified using nano-silica grafting.Hydrophilic nano-silica treated with water-soluble sodium dodecyl sulfate(SDS)and organic silane coupling agents was grafted onto the surface of ramie fiber.The surface roughness of the fibers was considerably increased after grafting.The nano-silica particles on the fiber surface enhanced the mechanical and thermal properties of the fiber-epoxy composite plates.Based on an analysis of contact angle measurements and a water absorption study,it was determined that the hydrophilicity of the treated fiber was weakened.
文摘In order to verify the possible use of ramie as feed for ruminants, a study was undertaken on the chemical and nutritional evaluation of different parts of this plant. Four stocks of samples picked up in two different periods （summer and autumn） were analyzed. The standard chemical composition was determined on the whole plant and on its parts, the study was particularly focused on leaves and tops, not used in fibre production and available as livestock feed. Organic matter enzymic digestibility （OMD） was determined on all the samples by a double step method based on cellnlolytic andproteolytic enzymes. The chemical analysis showed good crude proteins content in leaves, tops and whole plant： 17.00 ~ 1.52%, 15.25 ~ 0.77% and 11.79 ~ 3.32% on dry matter （DM） basis respectively and good acid （ADF） and neutral （NDF） detergent fibre fractions. Lignin and ash resulted high in all plant parts and organic matter （OM） was consequently low, ash analysis showed high calcium concentration, especially in leaves, with values exceeding 4% of din, whereas the other micro （except the lead） and macroelements were in a normal range. OMD and energy values resulted poor in leaves, tops and in the whole plant and lower than the other forages commonly used as feed for runninants, thus the utilisation of ramie plant and its by-products requests further investigations.
基金the National Natural Science Foundation of China (31000731)China Agriculture Research System (CARS-19-E12)
文摘As the most important cultural practices for ramie （Boehmeria nivea） production, the single effects of plant density and nitrogen （N）, phosphorus （P）, potassium （K） fertilization on yield are well documented. To achieve the high yield and quality of ramie fiber, it is principal to quantify the fertilizer dosage for ramie sustainable production. A central composite design （CCD） was adopted with three replications, for a two-year field experiment （2008-2009） in the Yangtze River Valley of China. The aim was to evaluate both the individual and combined effects of plant density and N, P, and K fertilization on yield and fiber quality. The effects of the four factors on yield and quality of ramie cultivar Huazhu 4 were tested. Then mathematical models of the relationship among the four factors affecting ramie production and quality were established and analyzed to optimize the four factors, and used to establish optimum cultivation methods for the elite cultivar suitable to this area of the Yangtze River Valley. Supplements of N （X2）, P 0（3） and K 0（4）, and the density （X0 with N （X2） interaction significantly influenced strength in tests of mature ramie. The influence on fiber yield in the two year tests by the four factors ranked as follows： X3〉X4〉X~〉X2. We established the optimization technique attaining yield of 2 600 kg ha-~ in the tests as following： density of 28 350-31 650 plants ha-1, and supplements of N, P and K of 363-387, 98.58-105.48 and 280.20- 319.8 kg ha-1, respectively. It was concluded that nitrogen mostly improved plant growth and fiber yield while potassium had discernible effects on fiber quality.
基金Project(07XD14029) supported by the Program of Shanghai Subject Chief ScientistProject(075207046) supported by the Fund of Shanghai International Co-operation of Science and Technology+1 种基金Project(075211015) supported by the Key Science and Technologies Research and Development Program of Shanghai, ChinaProject(NCET-07-0620) supported by the Program for New Century Excellent Talents in University, China
文摘The natural fiber/poly(lactic acid) (PLA) composites were prepared with ramie and jute short fiber as reinforcement and PLA as matrix. The mechanical and thermal properties of the composites were investigated. The results show that the properties of the composites are better than those of plain PLA. When the content of the fiber is 30%, the composites can get the best mechanical properties. The dynamic mechanical analysis results show that the storage moduli of the PLA/ramie and PLA/jute composites increase with respect to the plain PLA. The Vicat softening temperature of the composites is greatly higher than that of PLA. The results of thermogravimetric analysis show that adding fiber to the PLA matrix can improve the degradation temperature of PLA.
基金National Natural Science Foundation of China(No.50803010)Natural Science Foundation of Shanghai,China(No.14ZR1400100)。
文摘With the increasing awareness of environmental protection and rational utilization of resources,natural fiber reinforced composites have shown broad development prospects.Apocynum fiber,known as the“king of wild fiber”,not only has moisture absorption,air permeability,and good mechanical properties but also has many health-related advantages such as antibacterial properties.In this study,four types of needle-punched Apocynum fiber and ramie fiber mat reinforced polylactic acid(PLA)composites were fabricated.Mechanical and thermal properties of the composites were tested and analyzed.The results showed that compared with those of the ramie fiber finish needle-punched mat reinforced composites,the tensile strength and the tensile modulus of Apocynum fiber finish needle-punched mat reinforced composites had increased by 15.3%and 60.1%,respectively.In comparison,the bending strength and the bending modulus were decreased by 21.8%and 7.6%,respectively.Moreover,compared with the Apocynum fiber finish needled-punched mat reinforced composites and the ramie fiber finish needle-punched mat reinforced composites,the Apocynum 50/ramie 50 finish needle-punched mat reinforced composites had the best tensile and bending properties.The after-fracture morphology was detected by a scanning electron microscope(SEM).The thermal properties of the composites were also characterized.It was found that the thermal properties of the four types of composites showed very similar behaviors.
基金supported by the National Natural Science Foundation of China (30270849)
文摘To explore the role of ethylene in sexual determination in ramie, the ethylene release rates in ramie stem apex of different sex, bud of the same node in female and hermaphrodite ramie in the second crop, and single inflorescence of different sex in hermaphrodite ramie were measured by gas chromatography. Effects of two ethylene inhibitors on sex expression in ramie were investigated. The ethylene release rate of stem apex was higher in the second crop or female ramie than that in the third crop or hermaphrodite ramie during growth. Although ethylene release rates between lower nodes and higher nodes were little different, it was lower in the middle nodes in hermaphrodite ramie. The ethylene release rates were higher in the higher nodes of female ramie at the second crop. At the third crop, the ethylene release rates were higher in lower nodes, lower in middle nodes and then highest in higher nodes in female ramie. However, an opposite ethylene release pattern was observed in hermaphrodite ramie. The ethylene release rate was higher in female flower than male flower and mixed inflorescence in hermaphrodite ramie. The male flower could be distinctly induced by AVG （aminooethoxyvinylglycine）. The node of the first male flower, percentage of female flowers and ratio of female flowers to male in ramie were evidently depressed by AVG in contrast to water. The percentage of mixed male and female flowers was also increased and the percentage of female flower decreased by spraying AgNO3. There was a close relationship between sexual differentiation and ethylene release rate in ramie. The female ramie could be induced by high ethylene release rate. The female flower could be inhibited by AVG and AgNO3. AVG at a concentration of 300 mg L^-1 was most effective.
文摘Ramie (Boehmeria nivea L.) is one of the most important fiber crops and biomass materials. However, previous studies showed that ramie presented a very low nitrogen agronomy efficiency (NAE, 23.2%~27.8%) in traditional farming, and the nitrogen fertilizer was applied excessively in ramie field. Plant osmotic adjustment (OA) responses to environmental stresses positively and exhibits improvements in plant tolerance. Whereas results varied due to the complexity of plant-environment interactions and lack of insights of specific species. In order to improve ramie production through osmoregulation, our current study investigated the role of nitrogen application and osmotic adjustment in improving the growth and yield in two varieties of ramie (H2000-03 and Ceheng Jiama) with contrasting nitrogen use efficiency (NUE) grown at 5 different N rates including N0, N6, N9, N12 and N15;0, 6, 9, 12 and 15 mmol/L N, respectively. The results showed that ramie adapted to different nitrogen rates through OA and significant differences of osmolyte content between varieties only presented at the particular growth stage. Obvious inflexion of yield, osmolyte content involving proline, soluble protein (SP), soluble sugar (SS) and malonaldehyde (MDA);nitrogen sensitive index (NSI) and comprehensive evaluation (D) in both varieties were observed. Our results recommended that the overall lifting of OA at a lower N level and at the proper growth stage would be a reasonable approach for improving ramie NUE.
