The tendril is a climbing organ in cucurbits and functions in physical support and to avoid shading by neighboring vegetation.However,how cucurbits produce tendrils to obtain climbing ability is largely unknown.In thi...The tendril is a climbing organ in cucurbits and functions in physical support and to avoid shading by neighboring vegetation.However,how cucurbits produce tendrils to obtain climbing ability is largely unknown.In this study,tendril phenotypes were investigated during different developmental stages.Our results revealed that tendril growth exhibited an age-dependent pattern in cucurbits.Tendril growth was inhibited,and the tendril was formed as a short tendril[nonfunctional tendril(nonF-tendril),approximately 0.1 cm]during the seedling stage.In contrast,enhanced cell proliferation and cell expansion led to rapid elongation of the tendril during the climbing stage,and the tendril formed as a functional tendril(F-tendril,approximately 30 cm)to obtain climbing ability.RT-qPCR detection showed that age-dependent tendril growth correlated negatively with the abundance of the conserved age regulator CsmiR156.Defoliation induced CsmiR156 to inhibit CsSPLs,and F-tendril formation and climbing ability were delayed in defoliated cucumbers,which confirmed the role of CsmiR156 in regulating tendril growth in vivo.Additionally,exogenous gibberellin(GA)treatment showed that GA positively regulated tendril growth,and RT-qPCR detection showed that the GA bio-synthetic genes and metabolic genes were affected by age pathway,suggesting that the age pathway depended on GA bio-synthetic and metabolic pathway to regulate cell expansion to determine tendril growth.In summary,our work reveals that change in tendril type is an important marker of phase transition in cucumber,and tendril growth is regulated by an intrinsic developmental age signal,ensuring that the cucumber obtains climbing ability at a suitable age.展开更多
The continuous decrease of low-slope cropland resources caused by construction land crowding poses huge threat to regional sustainable development and food security.Slope spectrum analysis of topographic and geomorphi...The continuous decrease of low-slope cropland resources caused by construction land crowding poses huge threat to regional sustainable development and food security.Slope spectrum analysis of topographic and geomorphic features is considered as a digital terrain analysis method which reflects the macro-topographic features by using micro-topographic factors.However,pieces of studies have extended the concept of slope spectrum in the field of geoscience to construction land to explore its expansion law,while research on the slope trend of cropland from that perspective remains rare.To address the gap,in virtue of spatial analysis and geographically weighted regression(GWR)model,the cropland use change in the Yangtze River Basin(YRB)from 2000 to 2020 was analyzed and the driving factors were explored from the perspective of slope spectrum.Results showed that the slope spectrum curves of cropland area-frequency in the YRB showed a first upward then a downward trend.The change curve of the slope spectrum of cropland in each province(municipality)exhibited various distribution patterns.Quantitative analysis of morphological parameters of cropland slope spectrum revealed that the further down the YRB,the stronger the flattening characteristics,the more obvious the concentration.The province experienced the greatest downhill cropland climbing(CLC)was Shannxi,while province experienced the highest uphill CLC was Zhejiang.The most common cropland use change type in the YRB was horizontal expansion type.The factors affecting average cropland climbing index(ACCI)were quite stable in different periods,while population density(POP)changed from negative to positive during the study period.This research is of practical significance for the rational utilization of cropland at the watershed scale.展开更多
I finally climbed the Great Wall, A dream of my childhood; my heart is filled with pleasure at the indescribable beauty of the Wall. China’s ancient civilization is best documented by the grandeur of the Wall.
Background:Cross-sectional evidence and small-scale trials suggest positive effects of stair climbing on cardiometabolic disease and glucose regulation.However,few studies have examined the long-term association betwe...Background:Cross-sectional evidence and small-scale trials suggest positive effects of stair climbing on cardiometabolic disease and glucose regulation.However,few studies have examined the long-term association between stair climbing and the incidence of type 2 diabetes(T2D).We aimed to prospectively evaluate the association of stair climbing with T2D and assess modifications by genetic predisposition to T2D.Methods:We included 451,699 adults(mean age=56.3±8.1 years,mean±SD;55.2%females)without T2D at baseline in the UK Biobank and followed up to March 31,2021.Stair climbing information was collected through the touchscreen questionnaire.Genetic risk score for T2D consisted of 424 single nucleotide polymorphisms.Results:During a median follow up of 12.1 years,14,896 T2D cases were documented.Compared with participants who reported no stair climbing,those who climbed stairs regularly had a lower risk of incident T2D(10-50 steps/day:hazard ratio(HR)=0.95,95%confidence interval(95%CI):0.89-1.00;60-100 steps/day:HR=0.92,95%CI:0.87-0.98;110-150 steps/day:HR=0.86,95%CI:0.80-0.91;>150 steps/day:HR=0.93,95%CI:0.87-0.99,p for trend=0.0007).We observed a significant interaction between stair climbing and genetic risk score on the subsequent T2D risk(p for interaction=0.0004),where the risk of T2D showed a downward trend in subjects with low genetic risk and those who reported stair climbing activity of 110-150 steps/day appeared to have the lowest overall T2D risk among those with intermediate to high genetic risk.Conclusion:A higher number of stairs climbed at home was associated with lower T2D incidence risk,especially among individuals with a low genetic predisposition to T2D.These findings highlight that stair climbing,as incidental physical activity,offers a simple and low-cost complement to public health interventions for T2D prevention.展开更多
Slickwater-based fracturing fluid has recently garnered significant attention as the major fluid for volumetric fracturing;however,lots of challenges and limitations such as low viscosity,poor salt tolerance,and possi...Slickwater-based fracturing fluid has recently garnered significant attention as the major fluid for volumetric fracturing;however,lots of challenges and limitations such as low viscosity,poor salt tolerance,and possible formation damage hinder the application of the conventional simple slickwater-based fracturing fluid.In addition,nanomaterials have proven to be potential solutions or improvements to a number of challenges associated with the slickwater.In this paper,molybdenum disulfide(MoS_(2))nanosheets were chemically synthesized by hydrothermal method and applied to improve the performance of conventional slickwater-based fracturing fluid.Firstly,the microstructure characteristics and crystal type of the MoS_(2)nanosheets were analyzed by SEM,EDS,TEM,XPS,and Raman spectroscopy techniques.Then,a series of evaluation experiments were carried out to compare the performance of MoS_(2)nanosheet-modified slickwater with the conventional slickwater,including rheology,drag reduction,and sand suspension.Finally,the enhanced imbibition capacity and potential mechanism of the nanosheet-modified slickwater were systematically investigated.The results showed that the self-synthesized MoS_(2)nanosheets displayed a distinct ultrathin flake-like morphology and a lateral size in the range of tens of nanometers.In the nano-composites,each MoS_(2)nanosheet plays the role of cross-linking point,so as to make the spatial structure of the entire system more compact.Moreover,nanosheet-modified slickwater demonstrates more excellent properties in rheology,drag reduction,and sand suspension.The nanosheet-modified slickwater has a higher apparent viscosity after shearing 120 min under 90℃ and 170 s^(−1).The maximum drag reduction rate achieved 76.3%at 20℃,and the sand settling time of proppants with different mesh in the nano-composites was prolonged.Spontaneous imbibition experiments showed that the gel-breaking fluid of nanosheet-modified slickwater exhibited excellent capability of oil-detaching,and increase the oil recovery to∼35.43%.By observing and analyzing the interfacial behavior of MoS_(2)nanosheets under stimulated reservoir conditions,it was found that the presence of an interfacial tension gradient and the formation of a climbing film may play an essential role in the spontaneous imbibition mechanism.This work innovatively uses two-dimensional MoS_(2)nanosheets to modify regular slickwater and confirms the feasibility of flake-like nanomaterials to improve the performance of slickwater.The study also reveals the underlying mechanism of enhanced imbibition efficiency of the nano-composites.展开更多
Wireless Sensor Networks are composed of autonomous sensing devices which are interconnected to form a closed network.This closed network is intended to share sensitive location-centric information from a source node ...Wireless Sensor Networks are composed of autonomous sensing devices which are interconnected to form a closed network.This closed network is intended to share sensitive location-centric information from a source node to the base station through efficient routing mechanisms.The efficiency of the sensor node is energy bounded,acts as a concentrated area for most researchers to offer a solution for the early draining power of sensors.Network management plays a significant role in wireless sensor networks,which was obsessed with the factors like the reliability of the network,resource management,energy-efficient routing,and scalability of services.The topology of the wireless sensor networks acts dri-ven factor for network efficiency which can be effectively maintained by perform-ing the clustering process effectively.More solutions and clustering algorithms have been offered by various researchers,but the concern of reduced efficiency in the routing process and network management still exists.This research paper offers a hybrid algorithm composed of a memetic algorithm which is an enhanced version of a genetic algorithm integrated with the adaptive hill-climbing algorithm for performing energy-efficient clustering process in the wireless sensor networks.The memetic algorithm employs a local searching methodology to mitigate the premature convergence,while the adaptive hill-climbing algorithm is a local search algorithm that persistently migrates towards the increased elevation to determine the peak of the mountain(i.e.,)best cluster head in the wireless sensor networks.The proposed hybrid algorithm is compared with the state of art clus-tering algorithm to prove that the proposed algorithm outperforms in terms of a network life-time,energy consumption,throughput,etc.展开更多
In this paper,a new tracked wall climbing robot with permanent magnetic units is designed,and the tension degree of robot’s tracks is found to have a significant impact on the robot’s adsorption performance.This tra...In this paper,a new tracked wall climbing robot with permanent magnetic units is designed,and the tension degree of robot’s tracks is found to have a significant impact on the robot’s adsorption performance.This tracked wall climbing robot is a remotely controlled robot.All the control devices can be installed on the robot body.All the permanent magnetic units are arranged on the light track.In order to illustrate the relationship between the tension degree and the adsorption performance,when absorbed on the vertical surface and 180⁃degree inverted surface,the static force analysis of the robot is presented.Finally,experiments were demonstrated to prove that higher tension degree of tracks can make adsorption performance better.展开更多
A Mobile Ad-hoc NETwork(MANET)contains numerous mobile nodes,and it forms a structure-less network associated with wireless links.But,the node movement is the key feature of MANETs;hence,the quick action of the nodes ...A Mobile Ad-hoc NETwork(MANET)contains numerous mobile nodes,and it forms a structure-less network associated with wireless links.But,the node movement is the key feature of MANETs;hence,the quick action of the nodes guides a link failure.This link failure creates more data packet drops that can cause a long time delay.As a result,measuring accurate link failure time is the key factor in the MANET.This paper presents a Fuzzy Linear Regression Method to measure Link Failure(FLRLF)and provide an optimal route in the MANET-Internet of Things(IoT).This work aims to predict link failure and improve routing efficiency in MANET.The Fuzzy Linear Regression Method(FLRM)measures the long lifespan link based on the link failure.The mobile node group is built by the Received Signal Strength(RSS).The Hill Climbing(HC)method selects the Group Leader(GL)based on node mobility,node degree and node energy.Additionally,it uses a Data Gathering node forward the infor-mation from GL to the sink node through multiple GL.The GL is identified by linking lifespan and energy using the Particle Swarm Optimization(PSO)algo-rithm.The simulation results demonstrate that the FLRLF approach increases the GL lifespan and minimizes the link failure time in the MANET.展开更多
The excellent climbing performance of the gecko is inspiring engineers and researchers for the design of artificial systems aimed at moving on vertical surfaces. Climbing robots could perform many useful tasks such as...The excellent climbing performance of the gecko is inspiring engineers and researchers for the design of artificial systems aimed at moving on vertical surfaces. Climbing robots could perform many useful tasks such as surveillance, inspection, repair, cleaning, and exploration. This paper presents and discusses the design, fabrication, and evaluation of two climbing robots which mimic the gait of the gecko. The first robot is designed considering macro-scale operations on Earth and in space. The second robot, whose motion is controlled using shape memory alloy actuators, is designed to be easily scaled down for micro-scale applications. Proposed bionic systems can climb up 65 degree slopes at a speed of 20 mm·s^-1.展开更多
Climbing robots are of potential use for surveillance, inspection and exploration in different environments. In particular, the use of climbing robots for space exploration can allow scientists to explore environments...Climbing robots are of potential use for surveillance, inspection and exploration in different environments. In particular, the use of climbing robots for space exploration can allow scientists to explore environments too challenging for traditional wheeled designs. To adhere to surfaces, biomimetic dry adhesives based on gecko feet have been proposed. These biomimetic dry adhesives work by using multi-scale compliant mechanisms to make intimate contact with different surfaces and adhere by using Van der Waals forces. Fabrication of these adhesives has frequently been challenging however, due to the difficulty in combining macro, micro and nanoscale compliance. We present an all polymer foot design for use with a hexapod climbing robot and a fabrication method to improve reliability and yield. A high strength, low-modulus silicone, TC-5005, is used to form the foot base and microscale fibres in one piece by using a two part mold. A macroscale foot design is produced using a 3D printer to produce a base mold, while lithographic definition of microscale fibres in a thick photoresist forms the 'hairs' of the polymer foot. The adhesion of the silicone fibres by themselves or attached to the macro foot is examined to determine best strategies for placement and removal of feet to maximize adhesion. Results demonstrate the successful integration of micro and macro compliant feet for use in climbing on a variety of surfaces.展开更多
The superplastic behavior has been found in Fe 3Al and FeAl alloys with grain sizes of 100~600 μm. The large grained Fe 3Al and FeAl alloys exhibit all deformation characteristics of conventional fine grain size sup...The superplastic behavior has been found in Fe 3Al and FeAl alloys with grain sizes of 100~600 μm. The large grained Fe 3Al and FeAl alloys exhibit all deformation characteristics of conventional fine grain size superplastic alloys. However, superplastic behavior was found in large grained iron aluminides without the usual prerequisites for the superplasticity of a fine grain size and grain boundary sliding. The metallographic examinations have shown that average grain size of large grained iron aluminides decreased during superplastic deformation. Transmission electron microscopy (TEM) observations have shown that there were a great number of subgrain boundaries which formed a network and among which the proportion of low and high angle boundaries increased with the increase of strain. The observed superplastic phenomenon is explained by continuous recovery and recrystallization. During superplastic deformation, an unstable subgrain network forms and these subboundaries absorb gliding dislocations and transform into low and high angle grain boundaries. A dislocation gliding and climb process accommodated by subboundary sliding, migration and rotation, allows the superplastic flow to proceed.展开更多
Drosophila melanogaster mutants with deficient kynurenine (KYN) formation from tryptophan (TRP) have longer life span than wild type flies. Administration of alpha-methyl-TRP and 5-methyl-TRY, the inhibitors of TRP-KY...Drosophila melanogaster mutants with deficient kynurenine (KYN) formation from tryptophan (TRP) have longer life span than wild type flies. Administration of alpha-methyl-TRP and 5-methyl-TRY, the inhibitors of TRP-KYN metabolism, prolonged life span in wild-type flies. Both inhibitors are not available for human use. Berberine, an isoquinoline alkaloid isolated from berberis aristata is known as the herb widely used in traditional Chinese and Indian medicine. Berberin is a strong inhibitor of the enzyme catalyzing TRP conversion into KYN. Considering this particular feature we investigated the effect of berberine on life-and health-span in wild-type Drosophila melanogaster. The results of our study showed that Berberine extended mean, median and maximum life span of female flies. Berberine did not affect the number of pupae of filial generation and decreased their lethality. Berberine increased locomotor activity (vertical climbing). The results of the study suggest that berberine prolongs life- and improves health-span of Drosophila melanogaster. Berberine might be a candidate drug for prevention and treatment of aging and aging-associated medical and psychiatric disorders.展开更多
In this study, a complex analysis of a man-weapon interaction based on experimental effort is presented.The attention is focused on how a shooter can influence on a rifle, opposite to generally considered in literatur...In this study, a complex analysis of a man-weapon interaction based on experimental effort is presented.The attention is focused on how a shooter can influence on a rifle, opposite to generally considered in literature rifle's impact on a shooter. It is shown, based on the kbk AKM weapon, that each support point of the rifle has an substantial impact on the system. It is said that identifying human reactions on weapon may let to describe gun movement and thus may be applied to weapon accuracy determination.展开更多
A new method called critical suction is used based on the wall climbing robot demands of miniature structure, moving smartly and low noise. It makes the robot achieve the homeostasis state in the suction cup, and in t...A new method called critical suction is used based on the wall climbing robot demands of miniature structure, moving smartly and low noise. It makes the robot achieve the homeostasis state in the suction cup, and in this condition the robot can stay on the wall reliably and move smartly. The fluid mechanics model and fluid network model are set up to analyze the robot suction system when the airflow is steady or changes suddenly. Furthermore, simulation results indicate the close relation between the key parameters of robot structure and the suction system. Finally the method of critical suction proves correct in theory.展开更多
Trial mountain climbing algorithm to solve the inverse kinematics problem of redundant manipulator is introduced, and a method of describing a numeral with a special numeration system is given to define the changed st...Trial mountain climbing algorithm to solve the inverse kinematics problem of redundant manipulator is introduced, and a method of describing a numeral with a special numeration system is given to define the changed step of the trail mountain climbing algorithm. The results show that a likelihood solution can be found quickly in the infinite groups of likelihood solutions within the limited search times, and need not calculate the anti trigonometric function and the inverse matrix. In addition, this algorithm has many good qualities such as concise algorithm, tiny computation, fast convergence velocity, good stability and extensive adaptability.展开更多
基金supported by the Natural Science Foundation of Zhejiang province(Grant Nos.LZ20C150001,LY21C150002)National Natural Science Foundation of China(Grant No.32202583).
文摘The tendril is a climbing organ in cucurbits and functions in physical support and to avoid shading by neighboring vegetation.However,how cucurbits produce tendrils to obtain climbing ability is largely unknown.In this study,tendril phenotypes were investigated during different developmental stages.Our results revealed that tendril growth exhibited an age-dependent pattern in cucurbits.Tendril growth was inhibited,and the tendril was formed as a short tendril[nonfunctional tendril(nonF-tendril),approximately 0.1 cm]during the seedling stage.In contrast,enhanced cell proliferation and cell expansion led to rapid elongation of the tendril during the climbing stage,and the tendril formed as a functional tendril(F-tendril,approximately 30 cm)to obtain climbing ability.RT-qPCR detection showed that age-dependent tendril growth correlated negatively with the abundance of the conserved age regulator CsmiR156.Defoliation induced CsmiR156 to inhibit CsSPLs,and F-tendril formation and climbing ability were delayed in defoliated cucumbers,which confirmed the role of CsmiR156 in regulating tendril growth in vivo.Additionally,exogenous gibberellin(GA)treatment showed that GA positively regulated tendril growth,and RT-qPCR detection showed that the GA bio-synthetic genes and metabolic genes were affected by age pathway,suggesting that the age pathway depended on GA bio-synthetic and metabolic pathway to regulate cell expansion to determine tendril growth.In summary,our work reveals that change in tendril type is an important marker of phase transition in cucumber,and tendril growth is regulated by an intrinsic developmental age signal,ensuring that the cucumber obtains climbing ability at a suitable age.
基金supported in part by the Key Laboratory of Natural Resources Monitoring and Supervision in Southern Hilly Region,Ministry of Natural Resources(NRMSSHR2023Y02)Yunnan Key Laboratory of Plateau Geographic Processes and Environmental Changes(PGPEC2304)+1 种基金Yunnan Normal University,China.This study was also sponsored by the Scientific Research Project of Education Department of Hubei Province(Grant No.B2022262)the Philosophy and Social Sciences Research Project of Education Department of Hubei Province(Grant No.22G024).
文摘The continuous decrease of low-slope cropland resources caused by construction land crowding poses huge threat to regional sustainable development and food security.Slope spectrum analysis of topographic and geomorphic features is considered as a digital terrain analysis method which reflects the macro-topographic features by using micro-topographic factors.However,pieces of studies have extended the concept of slope spectrum in the field of geoscience to construction land to explore its expansion law,while research on the slope trend of cropland from that perspective remains rare.To address the gap,in virtue of spatial analysis and geographically weighted regression(GWR)model,the cropland use change in the Yangtze River Basin(YRB)from 2000 to 2020 was analyzed and the driving factors were explored from the perspective of slope spectrum.Results showed that the slope spectrum curves of cropland area-frequency in the YRB showed a first upward then a downward trend.The change curve of the slope spectrum of cropland in each province(municipality)exhibited various distribution patterns.Quantitative analysis of morphological parameters of cropland slope spectrum revealed that the further down the YRB,the stronger the flattening characteristics,the more obvious the concentration.The province experienced the greatest downhill cropland climbing(CLC)was Shannxi,while province experienced the highest uphill CLC was Zhejiang.The most common cropland use change type in the YRB was horizontal expansion type.The factors affecting average cropland climbing index(ACCI)were quite stable in different periods,while population density(POP)changed from negative to positive during the study period.This research is of practical significance for the rational utilization of cropland at the watershed scale.
文摘I finally climbed the Great Wall, A dream of my childhood; my heart is filled with pleasure at the indescribable beauty of the Wall. China’s ancient civilization is best documented by the grandeur of the Wall.
基金supported by the National Key Research and Development Program of China(grant number 2020YFC2006300)the Young Scientists Fund of the National Natural Science Foundation of China(grant number 82103835)。
文摘Background:Cross-sectional evidence and small-scale trials suggest positive effects of stair climbing on cardiometabolic disease and glucose regulation.However,few studies have examined the long-term association between stair climbing and the incidence of type 2 diabetes(T2D).We aimed to prospectively evaluate the association of stair climbing with T2D and assess modifications by genetic predisposition to T2D.Methods:We included 451,699 adults(mean age=56.3±8.1 years,mean±SD;55.2%females)without T2D at baseline in the UK Biobank and followed up to March 31,2021.Stair climbing information was collected through the touchscreen questionnaire.Genetic risk score for T2D consisted of 424 single nucleotide polymorphisms.Results:During a median follow up of 12.1 years,14,896 T2D cases were documented.Compared with participants who reported no stair climbing,those who climbed stairs regularly had a lower risk of incident T2D(10-50 steps/day:hazard ratio(HR)=0.95,95%confidence interval(95%CI):0.89-1.00;60-100 steps/day:HR=0.92,95%CI:0.87-0.98;110-150 steps/day:HR=0.86,95%CI:0.80-0.91;>150 steps/day:HR=0.93,95%CI:0.87-0.99,p for trend=0.0007).We observed a significant interaction between stair climbing and genetic risk score on the subsequent T2D risk(p for interaction=0.0004),where the risk of T2D showed a downward trend in subjects with low genetic risk and those who reported stair climbing activity of 110-150 steps/day appeared to have the lowest overall T2D risk among those with intermediate to high genetic risk.Conclusion:A higher number of stairs climbed at home was associated with lower T2D incidence risk,especially among individuals with a low genetic predisposition to T2D.These findings highlight that stair climbing,as incidental physical activity,offers a simple and low-cost complement to public health interventions for T2D prevention.
基金This research was financially supported by the National Natural Science Foundation of China(Grant Nos.52004306 and 52174045)the Strategic Cooperation Technology Projects of CNPC and CUPB(Grant Nos.ZLZX2020-01 and ZLZX2020-02)the National Sciencea and Technology Major Projects of China(Grant Nos.2016ZX05030005and 2016ZX05051003).
文摘Slickwater-based fracturing fluid has recently garnered significant attention as the major fluid for volumetric fracturing;however,lots of challenges and limitations such as low viscosity,poor salt tolerance,and possible formation damage hinder the application of the conventional simple slickwater-based fracturing fluid.In addition,nanomaterials have proven to be potential solutions or improvements to a number of challenges associated with the slickwater.In this paper,molybdenum disulfide(MoS_(2))nanosheets were chemically synthesized by hydrothermal method and applied to improve the performance of conventional slickwater-based fracturing fluid.Firstly,the microstructure characteristics and crystal type of the MoS_(2)nanosheets were analyzed by SEM,EDS,TEM,XPS,and Raman spectroscopy techniques.Then,a series of evaluation experiments were carried out to compare the performance of MoS_(2)nanosheet-modified slickwater with the conventional slickwater,including rheology,drag reduction,and sand suspension.Finally,the enhanced imbibition capacity and potential mechanism of the nanosheet-modified slickwater were systematically investigated.The results showed that the self-synthesized MoS_(2)nanosheets displayed a distinct ultrathin flake-like morphology and a lateral size in the range of tens of nanometers.In the nano-composites,each MoS_(2)nanosheet plays the role of cross-linking point,so as to make the spatial structure of the entire system more compact.Moreover,nanosheet-modified slickwater demonstrates more excellent properties in rheology,drag reduction,and sand suspension.The nanosheet-modified slickwater has a higher apparent viscosity after shearing 120 min under 90℃ and 170 s^(−1).The maximum drag reduction rate achieved 76.3%at 20℃,and the sand settling time of proppants with different mesh in the nano-composites was prolonged.Spontaneous imbibition experiments showed that the gel-breaking fluid of nanosheet-modified slickwater exhibited excellent capability of oil-detaching,and increase the oil recovery to∼35.43%.By observing and analyzing the interfacial behavior of MoS_(2)nanosheets under stimulated reservoir conditions,it was found that the presence of an interfacial tension gradient and the formation of a climbing film may play an essential role in the spontaneous imbibition mechanism.This work innovatively uses two-dimensional MoS_(2)nanosheets to modify regular slickwater and confirms the feasibility of flake-like nanomaterials to improve the performance of slickwater.The study also reveals the underlying mechanism of enhanced imbibition efficiency of the nano-composites.
文摘Wireless Sensor Networks are composed of autonomous sensing devices which are interconnected to form a closed network.This closed network is intended to share sensitive location-centric information from a source node to the base station through efficient routing mechanisms.The efficiency of the sensor node is energy bounded,acts as a concentrated area for most researchers to offer a solution for the early draining power of sensors.Network management plays a significant role in wireless sensor networks,which was obsessed with the factors like the reliability of the network,resource management,energy-efficient routing,and scalability of services.The topology of the wireless sensor networks acts dri-ven factor for network efficiency which can be effectively maintained by perform-ing the clustering process effectively.More solutions and clustering algorithms have been offered by various researchers,but the concern of reduced efficiency in the routing process and network management still exists.This research paper offers a hybrid algorithm composed of a memetic algorithm which is an enhanced version of a genetic algorithm integrated with the adaptive hill-climbing algorithm for performing energy-efficient clustering process in the wireless sensor networks.The memetic algorithm employs a local searching methodology to mitigate the premature convergence,while the adaptive hill-climbing algorithm is a local search algorithm that persistently migrates towards the increased elevation to determine the peak of the mountain(i.e.,)best cluster head in the wireless sensor networks.The proposed hybrid algorithm is compared with the state of art clus-tering algorithm to prove that the proposed algorithm outperforms in terms of a network life-time,energy consumption,throughput,etc.
基金the Beijing Natural Science Foundation(Grant No.3194047)the Joint Program of Beijing Municipal Foundation and Education Commission(Grant No.KZ202010009015)the National Natural Science Foundation of China(Grant No.51775002).
文摘In this paper,a new tracked wall climbing robot with permanent magnetic units is designed,and the tension degree of robot’s tracks is found to have a significant impact on the robot’s adsorption performance.This tracked wall climbing robot is a remotely controlled robot.All the control devices can be installed on the robot body.All the permanent magnetic units are arranged on the light track.In order to illustrate the relationship between the tension degree and the adsorption performance,when absorbed on the vertical surface and 180⁃degree inverted surface,the static force analysis of the robot is presented.Finally,experiments were demonstrated to prove that higher tension degree of tracks can make adsorption performance better.
文摘A Mobile Ad-hoc NETwork(MANET)contains numerous mobile nodes,and it forms a structure-less network associated with wireless links.But,the node movement is the key feature of MANETs;hence,the quick action of the nodes guides a link failure.This link failure creates more data packet drops that can cause a long time delay.As a result,measuring accurate link failure time is the key factor in the MANET.This paper presents a Fuzzy Linear Regression Method to measure Link Failure(FLRLF)and provide an optimal route in the MANET-Internet of Things(IoT).This work aims to predict link failure and improve routing efficiency in MANET.The Fuzzy Linear Regression Method(FLRM)measures the long lifespan link based on the link failure.The mobile node group is built by the Received Signal Strength(RSS).The Hill Climbing(HC)method selects the Group Leader(GL)based on node mobility,node degree and node energy.Additionally,it uses a Data Gathering node forward the infor-mation from GL to the sink node through multiple GL.The GL is identified by linking lifespan and energy using the Particle Swarm Optimization(PSO)algo-rithm.The simulation results demonstrate that the FLRLF approach increases the GL lifespan and minimizes the link failure time in the MANET.
文摘The excellent climbing performance of the gecko is inspiring engineers and researchers for the design of artificial systems aimed at moving on vertical surfaces. Climbing robots could perform many useful tasks such as surveillance, inspection, repair, cleaning, and exploration. This paper presents and discusses the design, fabrication, and evaluation of two climbing robots which mimic the gait of the gecko. The first robot is designed considering macro-scale operations on Earth and in space. The second robot, whose motion is controlled using shape memory alloy actuators, is designed to be easily scaled down for micro-scale applications. Proposed bionic systems can climb up 65 degree slopes at a speed of 20 mm·s^-1.
文摘Climbing robots are of potential use for surveillance, inspection and exploration in different environments. In particular, the use of climbing robots for space exploration can allow scientists to explore environments too challenging for traditional wheeled designs. To adhere to surfaces, biomimetic dry adhesives based on gecko feet have been proposed. These biomimetic dry adhesives work by using multi-scale compliant mechanisms to make intimate contact with different surfaces and adhere by using Van der Waals forces. Fabrication of these adhesives has frequently been challenging however, due to the difficulty in combining macro, micro and nanoscale compliance. We present an all polymer foot design for use with a hexapod climbing robot and a fabrication method to improve reliability and yield. A high strength, low-modulus silicone, TC-5005, is used to form the foot base and microscale fibres in one piece by using a two part mold. A macroscale foot design is produced using a 3D printer to produce a base mold, while lithographic definition of microscale fibres in a thick photoresist forms the 'hairs' of the polymer foot. The adhesion of the silicone fibres by themselves or attached to the macro foot is examined to determine best strategies for placement and removal of feet to maximize adhesion. Results demonstrate the successful integration of micro and macro compliant feet for use in climbing on a variety of surfaces.
文摘The superplastic behavior has been found in Fe 3Al and FeAl alloys with grain sizes of 100~600 μm. The large grained Fe 3Al and FeAl alloys exhibit all deformation characteristics of conventional fine grain size superplastic alloys. However, superplastic behavior was found in large grained iron aluminides without the usual prerequisites for the superplasticity of a fine grain size and grain boundary sliding. The metallographic examinations have shown that average grain size of large grained iron aluminides decreased during superplastic deformation. Transmission electron microscopy (TEM) observations have shown that there were a great number of subgrain boundaries which formed a network and among which the proportion of low and high angle boundaries increased with the increase of strain. The observed superplastic phenomenon is explained by continuous recovery and recrystallization. During superplastic deformation, an unstable subgrain network forms and these subboundaries absorb gliding dislocations and transform into low and high angle grain boundaries. A dislocation gliding and climb process accommodated by subboundary sliding, migration and rotation, allows the superplastic flow to proceed.
文摘Drosophila melanogaster mutants with deficient kynurenine (KYN) formation from tryptophan (TRP) have longer life span than wild type flies. Administration of alpha-methyl-TRP and 5-methyl-TRY, the inhibitors of TRP-KYN metabolism, prolonged life span in wild-type flies. Both inhibitors are not available for human use. Berberine, an isoquinoline alkaloid isolated from berberis aristata is known as the herb widely used in traditional Chinese and Indian medicine. Berberin is a strong inhibitor of the enzyme catalyzing TRP conversion into KYN. Considering this particular feature we investigated the effect of berberine on life-and health-span in wild-type Drosophila melanogaster. The results of our study showed that Berberine extended mean, median and maximum life span of female flies. Berberine did not affect the number of pupae of filial generation and decreased their lethality. Berberine increased locomotor activity (vertical climbing). The results of the study suggest that berberine prolongs life- and improves health-span of Drosophila melanogaster. Berberine might be a candidate drug for prevention and treatment of aging and aging-associated medical and psychiatric disorders.
文摘In this study, a complex analysis of a man-weapon interaction based on experimental effort is presented.The attention is focused on how a shooter can influence on a rifle, opposite to generally considered in literature rifle's impact on a shooter. It is shown, based on the kbk AKM weapon, that each support point of the rifle has an substantial impact on the system. It is said that identifying human reactions on weapon may let to describe gun movement and thus may be applied to weapon accuracy determination.
基金Sponsored byt he Scientific Research Foundation for Returned Overseas Chinese Scholars ,State Education Ministry(20060232001)
文摘A new method called critical suction is used based on the wall climbing robot demands of miniature structure, moving smartly and low noise. It makes the robot achieve the homeostasis state in the suction cup, and in this condition the robot can stay on the wall reliably and move smartly. The fluid mechanics model and fluid network model are set up to analyze the robot suction system when the airflow is steady or changes suddenly. Furthermore, simulation results indicate the close relation between the key parameters of robot structure and the suction system. Finally the method of critical suction proves correct in theory.
文摘Trial mountain climbing algorithm to solve the inverse kinematics problem of redundant manipulator is introduced, and a method of describing a numeral with a special numeration system is given to define the changed step of the trail mountain climbing algorithm. The results show that a likelihood solution can be found quickly in the infinite groups of likelihood solutions within the limited search times, and need not calculate the anti trigonometric function and the inverse matrix. In addition, this algorithm has many good qualities such as concise algorithm, tiny computation, fast convergence velocity, good stability and extensive adaptability.