This paper conducts the analysis on the dissemination mechanism and guiding tactics of public opinion in catastrophic event network. Opinion evolution mechanism can be roughly divided into two classes. One is the beli...This paper conducts the analysis on the dissemination mechanism and guiding tactics of public opinion in catastrophic event network. Opinion evolution mechanism can be roughly divided into two classes. One is the belief of people based on their neighbors, on the basis of the public opinion is in the social network of acquaintances. Such networks are mostly using cellular automata model for data simulation, the results of numerical simulation are speci? c to stabilize near the critical value show that the system will reach a critical stable state. The network information collection is the source of network public opinion monitoring its breadth and depth determine the monitoring results for the clear theme of public opinion information collection. Under this basis, this paper proposes the novel idea of making the dissemination mechanism easier. The proposed idea is novel and necessary, the effectiveness is proved via the theoretical analysis.展开更多
The vortex flame design process was investigated. Combine qualitative and CAE (computer-aided engineering) simulation proposed to fulfill the functional requirement. Guidance channel can produce an ornamental flame ...The vortex flame design process was investigated. Combine qualitative and CAE (computer-aided engineering) simulation proposed to fulfill the functional requirement. Guidance channel can produce an ornamental flame with acceptable height. The lift mechanism comprises a supporting member and bearing and allows moving to the predetermined height. It allows a user to add fuel and cleaning base parts safely. Rigid body linkage and flow field simulated enables fine tune of geometric parameters. Functional test and measurement are carried out to confirm the product features. The measured average temperature of the metal chassis is 37.25℃, and that of glass is 141℃.展开更多
Several argillaceous platforms lie along the Yellow River(YR) of the eastern Guide Basin, northeastern Tibetan Plateau, and their compositions, formation processes, and geomorphic evolution remain debated. Using fie...Several argillaceous platforms lie along the Yellow River(YR) of the eastern Guide Basin, northeastern Tibetan Plateau, and their compositions, formation processes, and geomorphic evolution remain debated. Using field survey data, sample testing, and high-resolution remote sensing images, the evolution of the Erlian mudflow fans are analyzed. The data show significant differences between fans on either side of the YR. On the right bank, fans are dilute debris flows consisting of sand and gravel. On the left bank, fans are viscosity mudflows consisting of red clay. The composition and formation processes of the left bank platforms indicate a rainfall-induced pluvial landscape. Fan evolution can be divided into two stages: early-stage fans pre-date 16 ka B.P., and formed during the last deglaciation; late-stage fans post-date 8 ka B.P.. Both stages were induced by climate change. The data indicate that during the Last Glacial Maximum, the northeastern Tibetan Plateau experienced a cold and humid climate characterized by high rainfall. From 16–8 ka, the YR cut through the Erlian early mudflow fan, resulting in extensive erosion. Since 8 ka, the river channel has migrated south by at least 1.25 km, and late stage mudflow fan formation has occurred.展开更多
Performance analysis and kinematic design of the 3-PUU pure translational parallel mechanism with vertical guide-ways are investigated. Two novel performance indices, the critical slider stroke and the main section ar...Performance analysis and kinematic design of the 3-PUU pure translational parallel mechanism with vertical guide-ways are investigated. Two novel performance indices, the critical slider stroke and the main section area of workspace, are defined; The expressions of two other indices, i.e. the global dexterity and global force transfer ratio are revised based on the main section of workspace. Using these indices, performance changes versus the varieties of dimensional parameters of mechanism are investigated in detail and the graphic descriptions of change tendencies of the performance indices are illustrated. By means of these obtained graphic descriptions, kinematic parameters for the 3-PUU pure translational parallel mechanism with better characteristics can be directly acquired.展开更多
A new thread guide mechanism of a rubbed roving frame is developed, which consists mainly of a plate cam, a linkage and an air bag spring. Characteristics and design parameters of the air spring are explored in this s...A new thread guide mechanism of a rubbed roving frame is developed, which consists mainly of a plate cam, a linkage and an air bag spring. Characteristics and design parameters of the air spring are explored in this study. Based on analyses of winding technology for this kind of package, the kinetic laws of the thread guide is put forward. General design equations of the cam profile are derived, and common kinetic laws of II linkage group which is used for such mechanism design is proposed. It proves theoretically that it is practicable. The experimental results indicate that it can meet the needs of technological demands, and the new thread guide mechanism has been used successfully on textile machines.展开更多
The non perturbative guiding center transformation is extended to the relativistic regime and takes into account electromagnetic fluctuations. The main solutions are obtained in covariant form: the gyrating particle a...The non perturbative guiding center transformation is extended to the relativistic regime and takes into account electromagnetic fluctuations. The main solutions are obtained in covariant form: the gyrating particle and the guiding particle solutions, both in gyro-kinetic as in MHD orderings. Moreover, the presence of a gravitational field is also considered. The way to introduce the gravitational field is original and based on the Einstein conjecture on the feasibility to extend the general relativity theory to include electromagnetism by geometry, if applied to the extended phase space. In gyro-kinetic theory, some interesting novelties appear in a natural way, such as the exactness of the conservation of a magnetic moment, or the fact that the gyro-phase is treated as the non observable fifth dimension of the Kaluza-Klein model. Electrodynamics becomes non local, without the inconsistency of self-energy. Finally, the gyrocenter transformation is considered in the presence of stochastic e.m. fluctuations for explaining quantum behaviors via Nelson’s approach. The gyrocenter law of motion is the Schrödinger equation.展开更多
Compliant mechanisms transfer an input force or displacement to another point through elastic body deformation. The field of compliant mechanisms is expected to continue to grow as materials with superior properties a...Compliant mechanisms transfer an input force or displacement to another point through elastic body deformation. The field of compliant mechanisms is expected to continue to grow as materials with superior properties are developed. The paper takes into consideration some typical spring guiding systems, being able to realize translating planar displacement of the link. Some types of compound spring guiding systems, such as S-shaped guiding spring system, U-shaped guiding spring system and four spring guiding system with additional rigid-body link have been considered and analyzed as compliant structures. The mobility as well as guiding accuracy of the developed compliant mechanisms, that is, their capability to realize translating planar displacement of the link, have been researched, and the optimal dimensions of the mechanism have been determined in order to provide minimal guiding inaccuracy.展开更多
By studying the e ects of geometric precision on kinematic accuracy, an error mapping model has been established, based on the hypothesis that a motion pair and its installation surface are rigid. However, when using ...By studying the e ects of geometric precision on kinematic accuracy, an error mapping model has been established, based on the hypothesis that a motion pair and its installation surface are rigid. However, when using this assumption,there is a significant error induced in high-precision computer numerical control(CNC) machine tools as compared with reality. One of the most important reasons for this error is failing to consider the error averaging e ect of motion pair elements. Therefore, this work examines a high-precision horizontal machining center as its research object, and analyzes the error averaging mechanism of a rolling guide pair under a deformation of the rolling elements. The carriage bearing forces caused by guideway straightness errors are obtained by constructing a geometric error model of a single carriage. The relationship between guideway straightness errors and carriage bearing forces is described by a transfer function in the spatial frequency domain, and its characteristics are analyzed. It quantifies the so-called error averaging e ect of the rolling guide system and, on this basis, a static model for four carriages is established to reflect the error averaging e ect of the rolling guide pair on the position and orientation errors of the motion pair. In addition, it is found that the wavelengths and phase di erences of guideway errors a ect this error averaging mechanism, but the amplitude and preload have little influence thereon. The experiment result shows that the kinematic straightness errors in the x-and y-directions were approximately 1/3 to 1/2 of the guideway straightness errors in the corresponding directions. The results can be used to guide the precision design and assembly of machine tools.展开更多
Nerve conduits enhance nerve regeneration in the repair of long-distance peripheral nerve defects. To help optimize the effectiveness of nerve conduits for nerve repair, we developed a multi-step electrospinning proce...Nerve conduits enhance nerve regeneration in the repair of long-distance peripheral nerve defects. To help optimize the effectiveness of nerve conduits for nerve repair, we developed a multi-step electrospinning process for constructing nerve guide conduits with aligned nanofibers. The alignment of the nerve guide conduits was characterized by scanning electron microscopy and fast Fourier transform. The mechanical performance of the nerve guide conduits was assessed by testing for tensile strength and compression resistance. The biological performance of the aligned fibers was examined using Schwann cells, PC12 cells and dorsal root ganglia in vitro. Immunohistochemistry was performed for the Schwann cell marker S100 and for the neurofilament protein NF200 in PC12 cells and dorsal root ganglia. In the in vivo experiment, a 1.5-cm defect model of the right sciatic nerve in adult female Sprague-Dawley rats was produced and bridged with an aligned nerve guide conduit. Hematoxylin-eosin staining and immunohistochemistry were used to observe the expression of ATF3 and cleaved caspase-3 in the regenerating matrix. The recovery of motor function was evaluated using the static sciatic nerve index. The number of myelinated fibers, axon diameter, fiber diameter, and myelin thickness in the distal nerve were observed by electron microscopy. Gastrocnemius muscle mass ratio was also determined. The analyses revealed that aligned nanofiber nerve guide conduits have good mechanical properties and can induce Schwann cells, PC12 cells and dorsal root ganglia to aggregate along the length of the nanofibers, and promote the growth of longer axons in the latter two(neuronal) cell types. The aligned fiber nerve conduits increased the expression of ATF3 and cleaved caspase-3 at the middle of the regenerative matrix and at the distal nerve segment, improved sciatic nerve function, increased muscle mass of the gastrocnemius muscle, and enhanced recovery of distal nerve ultrastructure. Collectively, the results show that highly aligned nanofibers improve the performance of the nerve conduit bridge, and enhance its effectiveness in repairing peripheral nerve defects.展开更多
A model of guided circumferential waves propagating in double-walled carbon nanotubes is built by the theory of wave propagation in continuum mechanics, while the van der Waals force between the inner and outer nanotu...A model of guided circumferential waves propagating in double-walled carbon nanotubes is built by the theory of wave propagation in continuum mechanics, while the van der Waals force between the inner and outer nanotube has been taken into account in the model. The dispersion curves of the guided circumferential wave propagation are studied, and some dispersion characteristics are illustrated by comparing with those of single-walled carbon nanotubes. It is found that in double-walled carbon nanotubes, the guided circumferential waves will propagate in more dispersive ways. More interactions between neighboring wave modes may take place. In particular, it has been found that a couple of wave modes may disappear at a certain frequency and that, while a couple of wave modes disappear, another new couple of wave modes are excited at the same wave number.展开更多
This study explores the potentials of employing an Organic Rankine Cycle (ORC) system with variable inlet guide vanes (VIV) turbine geometry designed on a GT-Suite platform for effective exhaust heat recovery (EHR) ap...This study explores the potentials of employing an Organic Rankine Cycle (ORC) system with variable inlet guide vanes (VIV) turbine geometry designed on a GT-Suite platform for effective exhaust heat recovery (EHR) application onboard passenger vehicles. The ORC model simulation was based on vehicle speed mode using R245fa as working fluid to assess the thermal performance of the ORC system when utilizing modified turbine geometry. Interestingly, the model achieved a very improved performance in contrast to the model without a modified turbine configuration. The results revealed the average 2.32 kW ORC net output, 4.93% thermal efficiency, 6.1% mechanical efficiency, and 5.0% improved brake specific fuel consumption (BSFC) for the developed model. As determined by the performance indicators, these promising results from the model study show the prospect of EHR technology application in the transportation sector for reduction in exhaust emissions and fuel savings.展开更多
A comparison between intensity noise spectra and also the line shapes of gain-guided, weakly-index-guided, and strongly-index-guided semiconductor lasers are made using numerical solution of Maxwell-Bloch equations in...A comparison between intensity noise spectra and also the line shapes of gain-guided, weakly-index-guided, and strongly-index-guided semiconductor lasers are made using numerical solution of Maxwell-Bloch equations including spontaneous emission noise.展开更多
文摘This paper conducts the analysis on the dissemination mechanism and guiding tactics of public opinion in catastrophic event network. Opinion evolution mechanism can be roughly divided into two classes. One is the belief of people based on their neighbors, on the basis of the public opinion is in the social network of acquaintances. Such networks are mostly using cellular automata model for data simulation, the results of numerical simulation are speci? c to stabilize near the critical value show that the system will reach a critical stable state. The network information collection is the source of network public opinion monitoring its breadth and depth determine the monitoring results for the clear theme of public opinion information collection. Under this basis, this paper proposes the novel idea of making the dissemination mechanism easier. The proposed idea is novel and necessary, the effectiveness is proved via the theoretical analysis.
文摘The vortex flame design process was investigated. Combine qualitative and CAE (computer-aided engineering) simulation proposed to fulfill the functional requirement. Guidance channel can produce an ornamental flame with acceptable height. The lift mechanism comprises a supporting member and bearing and allows moving to the predetermined height. It allows a user to add fuel and cleaning base parts safely. Rigid body linkage and flow field simulated enables fine tune of geometric parameters. Functional test and measurement are carried out to confirm the product features. The measured average temperature of the metal chassis is 37.25℃, and that of glass is 141℃.
基金financially supported by the National Nature Science Foundation of China under Grant No.41372333,41172158China Geological Survey(grant No.1212011220123)
文摘Several argillaceous platforms lie along the Yellow River(YR) of the eastern Guide Basin, northeastern Tibetan Plateau, and their compositions, formation processes, and geomorphic evolution remain debated. Using field survey data, sample testing, and high-resolution remote sensing images, the evolution of the Erlian mudflow fans are analyzed. The data show significant differences between fans on either side of the YR. On the right bank, fans are dilute debris flows consisting of sand and gravel. On the left bank, fans are viscosity mudflows consisting of red clay. The composition and formation processes of the left bank platforms indicate a rainfall-induced pluvial landscape. Fan evolution can be divided into two stages: early-stage fans pre-date 16 ka B.P., and formed during the last deglaciation; late-stage fans post-date 8 ka B.P.. Both stages were induced by climate change. The data indicate that during the Last Glacial Maximum, the northeastern Tibetan Plateau experienced a cold and humid climate characterized by high rainfall. From 16–8 ka, the YR cut through the Erlian early mudflow fan, resulting in extensive erosion. Since 8 ka, the river channel has migrated south by at least 1.25 km, and late stage mudflow fan formation has occurred.
基金This project is supported by National Natural Science Foundation of China (No.60275031)Municipal Key Lab Open Fund of Beijing, China (No.KP01-072200384).
文摘Performance analysis and kinematic design of the 3-PUU pure translational parallel mechanism with vertical guide-ways are investigated. Two novel performance indices, the critical slider stroke and the main section area of workspace, are defined; The expressions of two other indices, i.e. the global dexterity and global force transfer ratio are revised based on the main section of workspace. Using these indices, performance changes versus the varieties of dimensional parameters of mechanism are investigated in detail and the graphic descriptions of change tendencies of the performance indices are illustrated. By means of these obtained graphic descriptions, kinematic parameters for the 3-PUU pure translational parallel mechanism with better characteristics can be directly acquired.
文摘A new thread guide mechanism of a rubbed roving frame is developed, which consists mainly of a plate cam, a linkage and an air bag spring. Characteristics and design parameters of the air spring are explored in this study. Based on analyses of winding technology for this kind of package, the kinetic laws of the thread guide is put forward. General design equations of the cam profile are derived, and common kinetic laws of II linkage group which is used for such mechanism design is proposed. It proves theoretically that it is practicable. The experimental results indicate that it can meet the needs of technological demands, and the new thread guide mechanism has been used successfully on textile machines.
基金This work has been carried out within the framework of the Nonlinear Energetic Particle Dy-namics(NLED)European Enabling Research Project,WP 15-ER-01/ENEA-03,within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 633053.
文摘The non perturbative guiding center transformation is extended to the relativistic regime and takes into account electromagnetic fluctuations. The main solutions are obtained in covariant form: the gyrating particle and the guiding particle solutions, both in gyro-kinetic as in MHD orderings. Moreover, the presence of a gravitational field is also considered. The way to introduce the gravitational field is original and based on the Einstein conjecture on the feasibility to extend the general relativity theory to include electromagnetism by geometry, if applied to the extended phase space. In gyro-kinetic theory, some interesting novelties appear in a natural way, such as the exactness of the conservation of a magnetic moment, or the fact that the gyro-phase is treated as the non observable fifth dimension of the Kaluza-Klein model. Electrodynamics becomes non local, without the inconsistency of self-energy. Finally, the gyrocenter transformation is considered in the presence of stochastic e.m. fluctuations for explaining quantum behaviors via Nelson’s approach. The gyrocenter law of motion is the Schrödinger equation.
文摘Compliant mechanisms transfer an input force or displacement to another point through elastic body deformation. The field of compliant mechanisms is expected to continue to grow as materials with superior properties are developed. The paper takes into consideration some typical spring guiding systems, being able to realize translating planar displacement of the link. Some types of compound spring guiding systems, such as S-shaped guiding spring system, U-shaped guiding spring system and four spring guiding system with additional rigid-body link have been considered and analyzed as compliant structures. The mobility as well as guiding accuracy of the developed compliant mechanisms, that is, their capability to realize translating planar displacement of the link, have been researched, and the optimal dimensions of the mechanism have been determined in order to provide minimal guiding inaccuracy.
基金Supported by National Science and Technology Major Project of China(Grant No.2015ZX04005001)Tianjin Provincial Nature Science Foundation of China(Grant No.16JCZDJC38400)
文摘By studying the e ects of geometric precision on kinematic accuracy, an error mapping model has been established, based on the hypothesis that a motion pair and its installation surface are rigid. However, when using this assumption,there is a significant error induced in high-precision computer numerical control(CNC) machine tools as compared with reality. One of the most important reasons for this error is failing to consider the error averaging e ect of motion pair elements. Therefore, this work examines a high-precision horizontal machining center as its research object, and analyzes the error averaging mechanism of a rolling guide pair under a deformation of the rolling elements. The carriage bearing forces caused by guideway straightness errors are obtained by constructing a geometric error model of a single carriage. The relationship between guideway straightness errors and carriage bearing forces is described by a transfer function in the spatial frequency domain, and its characteristics are analyzed. It quantifies the so-called error averaging e ect of the rolling guide system and, on this basis, a static model for four carriages is established to reflect the error averaging e ect of the rolling guide pair on the position and orientation errors of the motion pair. In addition, it is found that the wavelengths and phase di erences of guideway errors a ect this error averaging mechanism, but the amplitude and preload have little influence thereon. The experiment result shows that the kinematic straightness errors in the x-and y-directions were approximately 1/3 to 1/2 of the guideway straightness errors in the corresponding directions. The results can be used to guide the precision design and assembly of machine tools.
基金supported by the National Natural Science Foundation of China,No.31771052(to YW)the National Basic Research Program of China(973 Program),No.2014CB542201(to JP)+4 种基金the National Key Research and Development Program of China,No.2016YFC1101601(to QZ),2017YFA0104702(to YW)the PLA General Hospital Translational Medicine Project of China,No.2016TM-030(to QZ)the Beijing Municipal Natural Science Foundation of China,No.7172202(to YW)the PLA Youth Training Project for Medical Science,China,No.16QNP144(to YW)the Beijing Municipal Science and Technology Project,China,No.Z161100005016059(to YW)
文摘Nerve conduits enhance nerve regeneration in the repair of long-distance peripheral nerve defects. To help optimize the effectiveness of nerve conduits for nerve repair, we developed a multi-step electrospinning process for constructing nerve guide conduits with aligned nanofibers. The alignment of the nerve guide conduits was characterized by scanning electron microscopy and fast Fourier transform. The mechanical performance of the nerve guide conduits was assessed by testing for tensile strength and compression resistance. The biological performance of the aligned fibers was examined using Schwann cells, PC12 cells and dorsal root ganglia in vitro. Immunohistochemistry was performed for the Schwann cell marker S100 and for the neurofilament protein NF200 in PC12 cells and dorsal root ganglia. In the in vivo experiment, a 1.5-cm defect model of the right sciatic nerve in adult female Sprague-Dawley rats was produced and bridged with an aligned nerve guide conduit. Hematoxylin-eosin staining and immunohistochemistry were used to observe the expression of ATF3 and cleaved caspase-3 in the regenerating matrix. The recovery of motor function was evaluated using the static sciatic nerve index. The number of myelinated fibers, axon diameter, fiber diameter, and myelin thickness in the distal nerve were observed by electron microscopy. Gastrocnemius muscle mass ratio was also determined. The analyses revealed that aligned nanofiber nerve guide conduits have good mechanical properties and can induce Schwann cells, PC12 cells and dorsal root ganglia to aggregate along the length of the nanofibers, and promote the growth of longer axons in the latter two(neuronal) cell types. The aligned fiber nerve conduits increased the expression of ATF3 and cleaved caspase-3 at the middle of the regenerative matrix and at the distal nerve segment, improved sciatic nerve function, increased muscle mass of the gastrocnemius muscle, and enhanced recovery of distal nerve ultrastructure. Collectively, the results show that highly aligned nanofibers improve the performance of the nerve conduit bridge, and enhance its effectiveness in repairing peripheral nerve defects.
文摘A model of guided circumferential waves propagating in double-walled carbon nanotubes is built by the theory of wave propagation in continuum mechanics, while the van der Waals force between the inner and outer nanotube has been taken into account in the model. The dispersion curves of the guided circumferential wave propagation are studied, and some dispersion characteristics are illustrated by comparing with those of single-walled carbon nanotubes. It is found that in double-walled carbon nanotubes, the guided circumferential waves will propagate in more dispersive ways. More interactions between neighboring wave modes may take place. In particular, it has been found that a couple of wave modes may disappear at a certain frequency and that, while a couple of wave modes disappear, another new couple of wave modes are excited at the same wave number.
文摘This study explores the potentials of employing an Organic Rankine Cycle (ORC) system with variable inlet guide vanes (VIV) turbine geometry designed on a GT-Suite platform for effective exhaust heat recovery (EHR) application onboard passenger vehicles. The ORC model simulation was based on vehicle speed mode using R245fa as working fluid to assess the thermal performance of the ORC system when utilizing modified turbine geometry. Interestingly, the model achieved a very improved performance in contrast to the model without a modified turbine configuration. The results revealed the average 2.32 kW ORC net output, 4.93% thermal efficiency, 6.1% mechanical efficiency, and 5.0% improved brake specific fuel consumption (BSFC) for the developed model. As determined by the performance indicators, these promising results from the model study show the prospect of EHR technology application in the transportation sector for reduction in exhaust emissions and fuel savings.
文摘A comparison between intensity noise spectra and also the line shapes of gain-guided, weakly-index-guided, and strongly-index-guided semiconductor lasers are made using numerical solution of Maxwell-Bloch equations including spontaneous emission noise.