Wireless capsule endoscopy(WCE)has the potential to fully replace conventional wired counterparts for its low invasiveness.Recent studies have attempted to expand the functions of capsules toward this goal.However,lim...Wireless capsule endoscopy(WCE)has the potential to fully replace conventional wired counterparts for its low invasiveness.Recent studies have attempted to expand the functions of capsules toward this goal.However,limitations in space and energy supply have resulted in the inability to perform multiple diagnostic and treatment tasks using a single capsule.In this study,we developed a dual-functional capsule robot(DFCR)for drug delivery and tissue biopsy based on magnetic torsion spring technology.The delivery module was shown to rotate the push rod with a thrust of 894 mN to release approximately 0.3 mL of semisolid drug.The biopsy module used a built-in blade to cut tissue with a shear stress of 22.87 MPa,producing a sample of approximately 1.8 mm3.Additionally,a five-degree-of-freedom permanent magnet drive system was developed.By adjusting the strength of the unidirectional magnetic field generated by an external magnet,the capsule can be wirelessly controlled to sequentially trigger the two functions.Ex vivo tests on porcine stomachs confirmed the feasibility of the prototype capsule(12 mm in diameter and 45 mm in length)in active movement,medication,and tissue biopsy.The newly developed DFCR further expands the clinical application prospects of WCE robots in minimally invasive surgery.展开更多
Being di erent from avoidance of singularity of closed-loop linkages, this paper employs the kinematic singularity to construct compliant mechanisms with expected nonlinear sti ness characteristics to enrich the metho...Being di erent from avoidance of singularity of closed-loop linkages, this paper employs the kinematic singularity to construct compliant mechanisms with expected nonlinear sti ness characteristics to enrich the methods of compliant mechanisms synthesis. The theory for generating kinetostatic nonlinear sti ness characteristic by the kinematic limb-singularity of a crank-slider linkage is developed. Based on the principle of virtual work, the kinetostatic model of the crank-linkage with springs is established. The influences of spring sti ness on the toque-position angle relation are analyzed. It indicates that corresponding spring sti ness may generate one of four types of nonlinear sti ness characteristics including the bi-stable, local negative-sti ness, zero-sti ness or positive-sti ness when the mechanism works around the kinematic limb-singularity position. Thus the compliant mechanism with an expected sti ness characteristic can be constructed by employing the pseudo rigid-body model of the mechanism whose joints or links are replaced by corresponding flexures. Finally, a tri-symmetrical constant-torque compliant mechanism is fabricated,where the curve of torque-position angle is obtained by an experimental testing. The measurement indicates that the compliant mechanism can generate a nearly constant-torque zone.展开更多
Different from the traditional railway trains,the combined levitation and guidance EDS maglev train is more likely to rotate after being disturbed.Therefore,the rotational electromagnetic stiffnesses are significant o...Different from the traditional railway trains,the combined levitation and guidance EDS maglev train is more likely to rotate after being disturbed.Therefore,the rotational electromagnetic stiffnesses are significant operating parameters for the train.In this paper,the different effects of each translational offset generated in the rotational motion on the corresponding rotational electromagnetic stiffnesses in the EDS maglev train are analyzed and calculated.Firstly,a three-dimensional model of the maglev train is established.Then,based on the space harmonic method and the equivalent circuit of the levitation and guidance circuits,the formulas of rolling,pitching and yawing stiffness are presented.Finally,by comparing with the three-dimensional finite element simulation results,the key translational displacements in the rotational motion which has a great impact on the stiffness are obtained.Hence,the three-dimensional analytical formula can be simplified and the computation can be reduced.In addition,the accuracy of the calculation results is verified by comparing with the experimental data of Yamanashi test line.展开更多
Based on the traditional optimization methods about the pressure control spring of the relief valve and combined with the advantages of neural network, this paper put forward the optimization method with many paramete...Based on the traditional optimization methods about the pressure control spring of the relief valve and combined with the advantages of neural network, this paper put forward the optimization method with many parameters and a lot of constraints based on neural network. The object function of optimization is transformed into the energy function of the neural network and the mathematical model of neural network optimization about the pressure control spring of the relief valve is set up in this method which also puts for ward its own algorithm. An example of application shows that network convergence gets stable state of minimization object function E, and object function converges to the utmost minimum point with steady function, then best solution is gained, which makes the design plan better. The algorithm of solution for the problem is effective about the optimum design of the pressure control spring and improves the performance target.展开更多
This paper looks at the new media, communication, and political environment in both Tunisia and Egypt during and after the revolution. The new environment provided activists, politicians, civil society, and youth amon...This paper looks at the new media, communication, and political environment in both Tunisia and Egypt during and after the revolution. The new environment provided activists, politicians, civil society, and youth among others, who want to express their opinions and share their views, with various channels and means of corranunication to be part of the political action and to participate in the decision-making process. Social media played an important role in mobilizing youth to rally and protest. This is to say that a new model of communication has emerged with this new environment. The receiver has become the sender and the producer of the message. The process of communication, therefore, has been changed from one to many to from many to many, and everybody became sender and receiver at the same time. The main research question this paper aims to answer is： Are social networks enough to change the political and economic scene in the Arab World？ And is there a relationship between the new communication environment and Arab spring？ The year 2011 has been in the Arab world the year of social networks and radical changes in the political scene where a score of dictators were ousted. New political communication networks and mechanisms took place, and for the first time in Arab political communication, public opinion was a major political player. Social networks helped tremendously the formation of new public sphere where the public finds its way in the media and communication processes. At their best, new media can mobilize crowds and masses to rally and protest. They can give a social perspective to movements. However, they can＇t make change and implement democracy. After the collapse of the regimes in Tunisia and Egypt, things are not getting any better. There is no democratic transition, and both countries are experiencing complex economic, social, and political problems.展开更多
The experiment was mainly used to study the effect of insect-proof net mulching cultivation technology on the temperature and humidity of the greenhouse and the spring shoot growth of citrus Shatangju. The results sho...The experiment was mainly used to study the effect of insect-proof net mulching cultivation technology on the temperature and humidity of the greenhouse and the spring shoot growth of citrus Shatangju. The results showed that the 40-mesh translucent insect-proof net had a positive effect on the spring shoot growth of Shatangju in the spring from January to April. In the meantime,according to the change of the temperature and humidity inside and outside the insect-proof net and the change of quantity of Aleyrodidae,Tetranychidae and Phyllocnisidae,it was found that the role of insect-proof net in enhancing the spring shoot growth of Shatangju was possibly achieved by the regulation of citrus pests and the temperature and humidity inside the net.展开更多
The Duffing equation describes the oscillations of a damped nonlinear oscillator [1]. Its non-linearity is confined to a one coordinate-dependent cubic term. Its applications describing a mechanical system is limited ...The Duffing equation describes the oscillations of a damped nonlinear oscillator [1]. Its non-linearity is confined to a one coordinate-dependent cubic term. Its applications describing a mechanical system is limited e.g. oscillations of a theoretical weightless-spring. We propose generalizing the mathematical features of the Duffing equation by including in addition to the cubic term unlimited number of odd powers of coordinate-dependent terms. The proposed generalization describes a true mass-less magneto static-spring capable of performing highly non-linear oscillations. The equation describing the motion is a super non-linear ODE. Utilizing Mathematica [2] we solve the equation numerically displaying its time series. We investigate the impact of the proposed generalization on a handful of kinematic quantities. For a comprehensive understanding utilizing Mathematica animation we bring to life the non-linear oscillations.展开更多
Geophysical surveys utilising magnetic and electromagnetic techniques were carried out at the Siloam hot spring. The spring is in the Soutpansberg Basin in the northern part of South Africa. The research was to invest...Geophysical surveys utilising magnetic and electromagnetic techniques were carried out at the Siloam hot spring. The spring is in the Soutpansberg Basin in the northern part of South Africa. The research was to investigate groundwater bearing structures at the hot spring. Magnetic survey results showed that the spring occurs between two north dipping dykes. The two dykes could be faulted segments of a single dyke or sill. Magnetic susceptibility results highlighted the presence of metamorphic and volcanic rocks. Electromagnetic survey results showed that the hot spring was within a roughly east to west trending, zone with high electrical conductivity values. Based on the survey results, water is exploiting fractures in the dyke or sill.展开更多
Background: The silica leaching attribute of some of the mystifying bacteria present in the cluster of hot springs (temperatures range 35°C - 80°C) at Bakreshwar (West Bengal, India, 23°52'...Background: The silica leaching attribute of some of the mystifying bacteria present in the cluster of hot springs (temperatures range 35°C - 80°C) at Bakreshwar (West Bengal, India, 23°52'48"N;87°22'40") has provided some significant advancements in construction technology when incorporated to the concrete/mortar specimens. The present investigation was designed to isolate other novel bacterial strains from 65°C hot spring that could have similar or better performance in construction technology. Methods: Soil sample collected from the 65°C hot spring was inoculated to the culture vials (incubated at 65°C) containing a specific synthetic growth medium (pH 8.0) to grow the bacterial population anaerobically by degassing the medium with CO<sub>2</sub> gas. Subsequent serial dilution techniques were employed to isolate pure culture of a specific bacterial strain. 16S rRNA gene sequence and phylogenetic analysis was carried out to identify the novelty of the isolated bacterial strain. The isolated bacteria were incorporated to the cement sand mixture at various cell concentrations to evaluate the efficacy of the strain in construction technology. Results: The work revealed the presence of a novel bacterial strain (BKH3;GenBank Accession No.: KP 890928) within the same hot spring consortium whose 16S rRNA gene sequence data showed 96% identity with Citrobacter freundii bacterial species. The newly isolated bacteria when incorporated at different cell concentration to the cement/cement-sand mixture were found to possess the similar compressive strength increment property, the cracks repairing ability and the water ingression resistivity. It also reduced the permeability of sulphate ions to the cementitious matrix reflecting the increment of durability of the incorporated material. Conclusions: The enhancement of compressive strength and durability of the as prepared bio-concrete material by using the isolated bacterial strain (BKH3) was due to the silica leaching activity of the bioremediase like protein secreted by the bacterium. This may open up another vista of utilization of hot spring bacterium for beneficial purposes in construction technology.展开更多
The Qinba Mountains are climatically and ecologically recognized as the north-south transitional zone of China.Analysis of its phenology is critical for comprehending the response of vegetation to climatic change.We r...The Qinba Mountains are climatically and ecologically recognized as the north-south transitional zone of China.Analysis of its phenology is critical for comprehending the response of vegetation to climatic change.We retrieved the start of spring phenology(SOS)of eight forest communities from the MODIS products and adopted it as an indicator for spring phenology.Trend analysis,partial correlation analysis,and GeoDetector were employed to reveal the spatio-temporal patterns and climatic drivers of SOS.The results indicated that the SOS presented an advance trend from 2001 to 2020,with a mean rate of−0.473 d yr^(−1).The SOS of most forests correlated negatively with air temperature(TEMP)and positively with precipitation(PRE),suggesting that rising TEMP and increasing PRE in spring would forward and delay SOS,respectively.The dominant factors influencing the sensitivity of SOS to climatic variables were altitude,forest type,and latitude,while the effects of slope and aspect were relatively minor.The response of SOS to climatic factors varied significantly in space and among forest communities,partly due to the influence of altitude,slope,and aspect.展开更多
基金supported by the National Natural Science Foundation of China(No.52105072)Zhejiang Provincial Natural Science Foundation of China(No.LZ24E050004)+2 种基金Jiangsu Provincial Outstanding Youth Program(No.BK20230072)a grant from Suzhou Industrial Foresight and Key Core Technology Project(No.SYC2022044)grants from Jiangsu Qinglan Project and Jiangsu 333 High-level Talents.
文摘Wireless capsule endoscopy(WCE)has the potential to fully replace conventional wired counterparts for its low invasiveness.Recent studies have attempted to expand the functions of capsules toward this goal.However,limitations in space and energy supply have resulted in the inability to perform multiple diagnostic and treatment tasks using a single capsule.In this study,we developed a dual-functional capsule robot(DFCR)for drug delivery and tissue biopsy based on magnetic torsion spring technology.The delivery module was shown to rotate the push rod with a thrust of 894 mN to release approximately 0.3 mL of semisolid drug.The biopsy module used a built-in blade to cut tissue with a shear stress of 22.87 MPa,producing a sample of approximately 1.8 mm3.Additionally,a five-degree-of-freedom permanent magnet drive system was developed.By adjusting the strength of the unidirectional magnetic field generated by an external magnet,the capsule can be wirelessly controlled to sequentially trigger the two functions.Ex vivo tests on porcine stomachs confirmed the feasibility of the prototype capsule(12 mm in diameter and 45 mm in length)in active movement,medication,and tissue biopsy.The newly developed DFCR further expands the clinical application prospects of WCE robots in minimally invasive surgery.
基金Supported by National Natural Science Foundation of China(Grant No.51605006)Research Foundation of Key Laboratory of Manufacturing Systems and Advanced Technology of Guangxi Province,China(Grant No.17-259-05-013K)
文摘Being di erent from avoidance of singularity of closed-loop linkages, this paper employs the kinematic singularity to construct compliant mechanisms with expected nonlinear sti ness characteristics to enrich the methods of compliant mechanisms synthesis. The theory for generating kinetostatic nonlinear sti ness characteristic by the kinematic limb-singularity of a crank-slider linkage is developed. Based on the principle of virtual work, the kinetostatic model of the crank-linkage with springs is established. The influences of spring sti ness on the toque-position angle relation are analyzed. It indicates that corresponding spring sti ness may generate one of four types of nonlinear sti ness characteristics including the bi-stable, local negative-sti ness, zero-sti ness or positive-sti ness when the mechanism works around the kinematic limb-singularity position. Thus the compliant mechanism with an expected sti ness characteristic can be constructed by employing the pseudo rigid-body model of the mechanism whose joints or links are replaced by corresponding flexures. Finally, a tri-symmetrical constant-torque compliant mechanism is fabricated,where the curve of torque-position angle is obtained by an experimental testing. The measurement indicates that the compliant mechanism can generate a nearly constant-torque zone.
基金supported in part by the National Natural Science Foundation of China under Grant(52077003 and 51777009)。
文摘Different from the traditional railway trains,the combined levitation and guidance EDS maglev train is more likely to rotate after being disturbed.Therefore,the rotational electromagnetic stiffnesses are significant operating parameters for the train.In this paper,the different effects of each translational offset generated in the rotational motion on the corresponding rotational electromagnetic stiffnesses in the EDS maglev train are analyzed and calculated.Firstly,a three-dimensional model of the maglev train is established.Then,based on the space harmonic method and the equivalent circuit of the levitation and guidance circuits,the formulas of rolling,pitching and yawing stiffness are presented.Finally,by comparing with the three-dimensional finite element simulation results,the key translational displacements in the rotational motion which has a great impact on the stiffness are obtained.Hence,the three-dimensional analytical formula can be simplified and the computation can be reduced.In addition,the accuracy of the calculation results is verified by comparing with the experimental data of Yamanashi test line.
文摘Based on the traditional optimization methods about the pressure control spring of the relief valve and combined with the advantages of neural network, this paper put forward the optimization method with many parameters and a lot of constraints based on neural network. The object function of optimization is transformed into the energy function of the neural network and the mathematical model of neural network optimization about the pressure control spring of the relief valve is set up in this method which also puts for ward its own algorithm. An example of application shows that network convergence gets stable state of minimization object function E, and object function converges to the utmost minimum point with steady function, then best solution is gained, which makes the design plan better. The algorithm of solution for the problem is effective about the optimum design of the pressure control spring and improves the performance target.
文摘This paper looks at the new media, communication, and political environment in both Tunisia and Egypt during and after the revolution. The new environment provided activists, politicians, civil society, and youth among others, who want to express their opinions and share their views, with various channels and means of corranunication to be part of the political action and to participate in the decision-making process. Social media played an important role in mobilizing youth to rally and protest. This is to say that a new model of communication has emerged with this new environment. The receiver has become the sender and the producer of the message. The process of communication, therefore, has been changed from one to many to from many to many, and everybody became sender and receiver at the same time. The main research question this paper aims to answer is： Are social networks enough to change the political and economic scene in the Arab World？ And is there a relationship between the new communication environment and Arab spring？ The year 2011 has been in the Arab world the year of social networks and radical changes in the political scene where a score of dictators were ousted. New political communication networks and mechanisms took place, and for the first time in Arab political communication, public opinion was a major political player. Social networks helped tremendously the formation of new public sphere where the public finds its way in the media and communication processes. At their best, new media can mobilize crowds and masses to rally and protest. They can give a social perspective to movements. However, they can＇t make change and implement democracy. After the collapse of the regimes in Tunisia and Egypt, things are not getting any better. There is no democratic transition, and both countries are experiencing complex economic, social, and political problems.
基金Supported by Special Construction Project of Modern Agriculture(Citrus)Industry Technology System(cars-27)
文摘The experiment was mainly used to study the effect of insect-proof net mulching cultivation technology on the temperature and humidity of the greenhouse and the spring shoot growth of citrus Shatangju. The results showed that the 40-mesh translucent insect-proof net had a positive effect on the spring shoot growth of Shatangju in the spring from January to April. In the meantime,according to the change of the temperature and humidity inside and outside the insect-proof net and the change of quantity of Aleyrodidae,Tetranychidae and Phyllocnisidae,it was found that the role of insect-proof net in enhancing the spring shoot growth of Shatangju was possibly achieved by the regulation of citrus pests and the temperature and humidity inside the net.
文摘The Duffing equation describes the oscillations of a damped nonlinear oscillator [1]. Its non-linearity is confined to a one coordinate-dependent cubic term. Its applications describing a mechanical system is limited e.g. oscillations of a theoretical weightless-spring. We propose generalizing the mathematical features of the Duffing equation by including in addition to the cubic term unlimited number of odd powers of coordinate-dependent terms. The proposed generalization describes a true mass-less magneto static-spring capable of performing highly non-linear oscillations. The equation describing the motion is a super non-linear ODE. Utilizing Mathematica [2] we solve the equation numerically displaying its time series. We investigate the impact of the proposed generalization on a handful of kinematic quantities. For a comprehensive understanding utilizing Mathematica animation we bring to life the non-linear oscillations.
文摘Geophysical surveys utilising magnetic and electromagnetic techniques were carried out at the Siloam hot spring. The spring is in the Soutpansberg Basin in the northern part of South Africa. The research was to investigate groundwater bearing structures at the hot spring. Magnetic survey results showed that the spring occurs between two north dipping dykes. The two dykes could be faulted segments of a single dyke or sill. Magnetic susceptibility results highlighted the presence of metamorphic and volcanic rocks. Electromagnetic survey results showed that the hot spring was within a roughly east to west trending, zone with high electrical conductivity values. Based on the survey results, water is exploiting fractures in the dyke or sill.
文摘Background: The silica leaching attribute of some of the mystifying bacteria present in the cluster of hot springs (temperatures range 35°C - 80°C) at Bakreshwar (West Bengal, India, 23°52'48"N;87°22'40") has provided some significant advancements in construction technology when incorporated to the concrete/mortar specimens. The present investigation was designed to isolate other novel bacterial strains from 65°C hot spring that could have similar or better performance in construction technology. Methods: Soil sample collected from the 65°C hot spring was inoculated to the culture vials (incubated at 65°C) containing a specific synthetic growth medium (pH 8.0) to grow the bacterial population anaerobically by degassing the medium with CO<sub>2</sub> gas. Subsequent serial dilution techniques were employed to isolate pure culture of a specific bacterial strain. 16S rRNA gene sequence and phylogenetic analysis was carried out to identify the novelty of the isolated bacterial strain. The isolated bacteria were incorporated to the cement sand mixture at various cell concentrations to evaluate the efficacy of the strain in construction technology. Results: The work revealed the presence of a novel bacterial strain (BKH3;GenBank Accession No.: KP 890928) within the same hot spring consortium whose 16S rRNA gene sequence data showed 96% identity with Citrobacter freundii bacterial species. The newly isolated bacteria when incorporated at different cell concentration to the cement/cement-sand mixture were found to possess the similar compressive strength increment property, the cracks repairing ability and the water ingression resistivity. It also reduced the permeability of sulphate ions to the cementitious matrix reflecting the increment of durability of the incorporated material. Conclusions: The enhancement of compressive strength and durability of the as prepared bio-concrete material by using the isolated bacterial strain (BKH3) was due to the silica leaching activity of the bioremediase like protein secreted by the bacterium. This may open up another vista of utilization of hot spring bacterium for beneficial purposes in construction technology.
基金National Key Research and Development Program of China,No.2023YFE0208100,No.2021YFC3000201Natural Science Foundation of Henan Province,No.232300420165。
文摘The Qinba Mountains are climatically and ecologically recognized as the north-south transitional zone of China.Analysis of its phenology is critical for comprehending the response of vegetation to climatic change.We retrieved the start of spring phenology(SOS)of eight forest communities from the MODIS products and adopted it as an indicator for spring phenology.Trend analysis,partial correlation analysis,and GeoDetector were employed to reveal the spatio-temporal patterns and climatic drivers of SOS.The results indicated that the SOS presented an advance trend from 2001 to 2020,with a mean rate of−0.473 d yr^(−1).The SOS of most forests correlated negatively with air temperature(TEMP)and positively with precipitation(PRE),suggesting that rising TEMP and increasing PRE in spring would forward and delay SOS,respectively.The dominant factors influencing the sensitivity of SOS to climatic variables were altitude,forest type,and latitude,while the effects of slope and aspect were relatively minor.The response of SOS to climatic factors varied significantly in space and among forest communities,partly due to the influence of altitude,slope,and aspect.
