Low-frequency carbody swaying phenomenon often occurs to railway vehicles due to hunting instability,which seriously deteriorates the ride comfort of passengers.This paper investigates low-frequency carbody swaying th...Low-frequency carbody swaying phenomenon often occurs to railway vehicles due to hunting instability,which seriously deteriorates the ride comfort of passengers.This paper investigates low-frequency carbody swaying through experimental analysis and numerical simulation.In the tests,the carbody acceleration,the wheel-rail profiles,and the dynamic characteristics of dampers were measured to understand the characteristics of the abnormal carbody vibration and to find out its primary contributor.Linear and nonlinear numerical simulations on the mechanism and optimization measures were carried out to solve this carbody swaying issue.The results showed that the carbody swaying is the manifest of carbody hunting instability.The low equivalent conicity and the decrease of dynamic damping of the yaw damper are probably the cause of this phenomenon.The optimization measures to increase the equivalent conicity and dynamic damping of the yaw damper were put forward and verified by on-track tests.The results of this study could enrich the knowledge of carbody hunting and provide a reference for solving abnormal carbody vibrations.展开更多
By analyzing the deficiencies of the method, a measurement system with the technologies of photoelectricity, laser and digital image processing to synthetically measure these two parameters has been developed. A tradi...By analyzing the deficiencies of the method, a measurement system with the technologies of photoelectricity, laser and digital image processing to synthetically measure these two parameters has been developed. A traditional method to measure the swaying quantity and multi-barrel parallelism of rocket launcher is introduced. Meanwhile, the principle, executive plan and the accuracy analysis are also presented. The photoelectric measurement system has been applied in the swaying quantity and multi-barrel parallelism measurement for Φ122 mm and Φ302 mm rocket launcher. The metrical errors are both 16^th.展开更多
Introduced is a traditional method for measuring the swaying and multi-barrel parallelism, and deficiencies are analyzed too. Based on that, expatiated is a new method of using a set of equipments to measure the two p...Introduced is a traditional method for measuring the swaying and multi-barrel parallelism, and deficiencies are analyzed too. Based on that, expatiated is a new method of using a set of equipments to measure the two parameters synthetically, adopting integrative photoelectric inspecting technique, laser technique and computer picture processing technique.展开更多
Objective To compare the difference in the effect of modified green dragon swaying its tail needling manipulation and common needling manipulations on the overall rating of pain of patients with knee osteoarthritis, a...Objective To compare the difference in the effect of modified green dragon swaying its tail needling manipulation and common needling manipulations on the overall rating of pain of patients with knee osteoarthritis, and to evaluate the advantages of modified green dragon swaying its tail needling manipulation for. Methods Ninety-five patients with knee osteoarthritis were divided into 2 groups according to the random number table method with 48 patients in the modified green dragon swaying its tail group(group special manipulation, SM group for short) and 47 patients in the common acupuncture group(group convention needling, CN group for short), and different acupuncture manipulations were applied in the two groups. Internationally recognized Simplified Mc Gill Pain Questionnaire(SF-MPQ) scale used for description and measurement of pain was applied to evaluate the pain degree, including pain rating index(PRI), visnal analogue scale(VAS)and present pain intensity(PPI). The index of severity for osteoarthritis(ISOA) was adopted for evaluation of clinical efficacy. Results(1) In SM group, the scores of PRI, VAS and PPI were 6.63±4.67, 2.23±1.45 and 0.65±1.32, respectively, after treatment, and in CN group, the scores of PRI, VAS and PPI were 13.32±7.96, 4.34±1.79 and 2.28±1.21, respectively, the scores decreased in the two groups after treatment(all P〈0.05), and the improvement in SM group was superior to that in CN group(all P〈0.01).(2) The clinical cure rate in SM group was 52.08%, and the total effective rate was 97.92%, the clinical cure rate in CN group was 25.53%, and the total effective rate was 85.10%. The comparison of clinical cure rate in the two groups showed that P〈0.01. Conclusion The SM group is obviously superior to CN group in the improvement of overall rating of pain of patients. It is indicated that modified green dragon swaying its tail acupuncture therapy can effectively relieve the pain of patients with knee osteoarthritis, which was worthy of popularization and application with definite clinical efficacy展开更多
Conventional Bāliáo(八髎) was used to treat constipation,green dragon swaying its tail and white tiger shaking its head manipulation was applied and sound effect was found.
A liquid launch vehicle is an important carrier in aviation,and its regular operation is essential to maintain space security.In the safety assessment of fluid launch vehicle body structure,it is necessary to ensure t...A liquid launch vehicle is an important carrier in aviation,and its regular operation is essential to maintain space security.In the safety assessment of fluid launch vehicle body structure,it is necessary to ensure that the assessmentmodel can learn self-response rules from various uncertain data and not differently to provide a traceable and interpretable assessment process.Therefore,a belief rule base with interpretability(BRB-i)assessment method of liquid launch vehicle structure safety status combines data and knowledge.Moreover,an innovative whale optimization algorithm with interpretable constraints is proposed.The experiments are carried out based on the liquid launch vehicle safety experiment platform,and the information on the safety status of the liquid launch vehicle is obtained by monitoring the detection indicators under the simulation platform.The MSEs of the proposed model are 3.8000e-03,1.3000e-03,2.1000e-03,and 1.8936e-04 for 25%,45%,65%,and 84%of the training samples,respectively.It can be seen that the proposed model also shows a better ability to handle small sample data.Meanwhile,the belief distribution of the BRB-i model output has a high fitting trend with the belief distribution of the expert knowledge settings,which indicates the interpretability of the BRB-i model.Experimental results show that,compared with other methods,the BRB-i model guarantees the model’s interpretability and the high precision of experimental results.展开更多
Arc spraying with the cored wires was applied to deposit FeMnCr/Cr3C2 coatings on low carbon steel substrates, namely FM1, FM2 and FM3. Thermal shock resistances of the coatings were investigated to assess the influen...Arc spraying with the cored wires was applied to deposit FeMnCr/Cr3C2 coatings on low carbon steel substrates, namely FM1, FM2 and FM3. Thermal shock resistances of the coatings were investigated to assess the influence of Cr3C2 content on thermal shock resistance. Characteristics of the coatings under thermal cycling test were studied by optical microscopy, field emission scanning electron microscope (FE-SEM) and energy dispersion spectrum (EDS), X-ray diffraction (XRD). The experimental results show that hardness of the coatings increases, bonding strength decreases slightly with increase of the Cr3C2 content of the coatings. As a result, FM2 coating possesses the best thermal shock resistance, attributing to its better thermal expansion matches and wettability than those of FM3 coating, less oxide rate than that of FM1 coating restraining from cracks formation and propagation in coatings.展开更多
In this paper, the influence depths of all levels of wind power produced waves are reckoned according to the measured swaying degree when a submarine meets with a force 11 strong tropical storm and has to submerge; Th...In this paper, the influence depths of all levels of wind power produced waves are reckoned according to the measured swaying degree when a submarine meets with a force 11 strong tropical storm and has to submerge; Then the minimum submergence depth is given when a submarine is faced with weather systems with force ≥ 6 wind and the swaying degree of less than 12 degree is assured as reference for a submarine working and sailing in big strong winds and waves.展开更多
The second order effect is the interaction between the vertical load and the deformation in a vertically forced element. In order to deduce a more brief but practical method, which has considered the second order effe...The second order effect is the interaction between the vertical load and the deformation in a vertically forced element. In order to deduce a more brief but practical method, which has considered the second order effect in a sway frame, some factors which affect the second order deformation in a sway frame should be generalized based on a more accurate method. Nonlinear finite element is adopted in this paper, and according to this theory, a program, which can calculate the inner force and the deformation of the sway frame considering the second order effects is coded.展开更多
In this paper, the transportation mode of tube during the immersed tunnel engineering in Yangtze River incorporated, mathematical models of the combination of the tube and four barges are established when it is towed ...In this paper, the transportation mode of tube during the immersed tunnel engineering in Yangtze River incorporated, mathematical models of the combination of the tube and four barges are established when it is towed by a tugboat through an elastic rope and pushed by two pushers. Based on evaluating the hydrodynamic derivatives by regressive formula, the simulations and analysis of the whole maneuvering motion course are accomplished. They include sway and yaw motion simulation of the combination and prediction of maneuvering motion such as turning circles of different rudder angle under the condition of being pushed by two pushers. The coincidence of the prediction with the results of model test is good.展开更多
The passive anti-rolling tank is one of important ship stabilizers widely used today. But at present, research of the tank is most aimed at its rolling movement. In this paper, the influence of sway motion on the pass...The passive anti-rolling tank is one of important ship stabilizers widely used today. But at present, research of the tank is most aimed at its rolling movement. In this paper, the influence of sway motion on the passive anti-rolling tank is considered, the mathematical model of "ship-passive antl-rolling tank" system coupled with sway motion is developed basing on the U-shaped passive anti-rolling tank theory. Both simulation results and experimental data indicate that it is necessary to consider the influence of sway motion on the anti-rolling tank, which is more agreeable to the actual circumstance.展开更多
AIM: To examine whether the sedative effects assessed by psychomotor tests would depend on the cytochrome P450 (CYP ) 2C19 genotypes after an infusion regimen of diazepam commonly used forgastrointestinal endoscopy in...AIM: To examine whether the sedative effects assessed by psychomotor tests would depend on the cytochrome P450 (CYP ) 2C19 genotypes after an infusion regimen of diazepam commonly used forgastrointestinal endoscopy in Japan. METHODS: Fifteen healthy Japanese volunteers consisting of three different CYP2C19 genotype groups underwent a critical ? icker fusion test, an eye movement analysis and a postural sway test as a test for physical sedative effects, and a visual analog scale (VAS) symptom assessment method as a test for mental sedative effects during the 336 h period after the intravenous infusion of diazepam (5 mg). RESULTS: The physical sedative effects assessed by the critical flicker test continued for 1 h (t values of 5 min, 30 min and 60 min later: 4.35, 5.00 and 3.19, respectively) and those by the moving radial area of a postural sway test continued for 3 h (t values of 5 h, 30 h, 60 min and 3 h later: -4.05, -3.42, -2.17 and -2.58, respectively), which changed significantly compared with the baseline level before infusion (P < 0.05). On the other hand, the mental sedative effects by the VAS method improved within 1 h. The CYP2C19 genotype-dependent differences in the postinfusion sedative effects were not observed in any of the four psychomotor function tests. CONCLUSION: With the psychomotor tests, the objective sedative effects of diazepam continued for 1 h to 3 h irrespective of CYP2C19 genotype status and the subjective sedative symptoms improved within 1 h. Up to 3 h of clinical care appears to be required after the infusion of diazepam, although patients feel subjectively improved.展开更多
The sloshing flows in a LNG cargo tank model (1/50 scale) of a ship are measured by an embedded pano- ramicPIV system. The measurement system consists of a Nd-Yag laser(120mJ, 15Hz), two cameras(lk x lk) and a h...The sloshing flows in a LNG cargo tank model (1/50 scale) of a ship are measured by an embedded pano- ramicPIV system. The measurement system consists of a Nd-Yag laser(120mJ, 15Hz), two cameras(lk x lk) and a host computer. Four experimental cases were tested for the tank model, in which swaying motions are made by a 6 DOF-motion platform. The amplitudes of swaying are 9.76mm and 29.29mm, and the swaying frequencies are 0.633Hz and 0.828Hz. The measurement regions are the vertical plane 50ram away from the front wall of the tank where a pump tower is installed. It was verified that the flow patterns of the sloshing are similar to each other when the swaying amplitudes are similar.展开更多
An improved meshing method based on Fluent is used to update the computational meshes in solving the Navier-Stokes (N-S) equations for viscous and incompressible free surface flows with the volume of fluid (VOF) m...An improved meshing method based on Fluent is used to update the computational meshes in solving the Navier-Stokes (N-S) equations for viscous and incompressible free surface flows with the volume of fluid (VOF) method. To maintain the mesh quality when updating meshes for a moving structure, the computational domain is separated into several parts and each part corre- sponds to a specific type of body motion. The numerical results of the interaction between the floating body and the regular waves agree well with the experimental data. A total of eight typical motion types are simulated separately to understand the correlation between the motion types and the wave transmission as well as the forces acting on the floating body. Numerical experiments show that the wave transmission increases in the case of sway and heave motions and decreases in the case of pitch motion as compared with the stationary case. It is also found that the sway motion reduces the horizontal wave force acting on the floating body, while the heave motion enhances the vertical wave force.展开更多
基金supported by the National Key R&D Program of China under grant number 2018YFB1201701.
文摘Low-frequency carbody swaying phenomenon often occurs to railway vehicles due to hunting instability,which seriously deteriorates the ride comfort of passengers.This paper investigates low-frequency carbody swaying through experimental analysis and numerical simulation.In the tests,the carbody acceleration,the wheel-rail profiles,and the dynamic characteristics of dampers were measured to understand the characteristics of the abnormal carbody vibration and to find out its primary contributor.Linear and nonlinear numerical simulations on the mechanism and optimization measures were carried out to solve this carbody swaying issue.The results showed that the carbody swaying is the manifest of carbody hunting instability.The low equivalent conicity and the decrease of dynamic damping of the yaw damper are probably the cause of this phenomenon.The optimization measures to increase the equivalent conicity and dynamic damping of the yaw damper were put forward and verified by on-track tests.The results of this study could enrich the knowledge of carbody hunting and provide a reference for solving abnormal carbody vibrations.
文摘By analyzing the deficiencies of the method, a measurement system with the technologies of photoelectricity, laser and digital image processing to synthetically measure these two parameters has been developed. A traditional method to measure the swaying quantity and multi-barrel parallelism of rocket launcher is introduced. Meanwhile, the principle, executive plan and the accuracy analysis are also presented. The photoelectric measurement system has been applied in the swaying quantity and multi-barrel parallelism measurement for Φ122 mm and Φ302 mm rocket launcher. The metrical errors are both 16^th.
文摘Introduced is a traditional method for measuring the swaying and multi-barrel parallelism, and deficiencies are analyzed too. Based on that, expatiated is a new method of using a set of equipments to measure the two parameters synthetically, adopting integrative photoelectric inspecting technique, laser technique and computer picture processing technique.
基金Supported by Scientific research project of traditional Chinese medicine of Hubei Province in 2014,research project at the academy level of Hubei Provincial Hospital of TCM:JDZX2014Y06
文摘Objective To compare the difference in the effect of modified green dragon swaying its tail needling manipulation and common needling manipulations on the overall rating of pain of patients with knee osteoarthritis, and to evaluate the advantages of modified green dragon swaying its tail needling manipulation for. Methods Ninety-five patients with knee osteoarthritis were divided into 2 groups according to the random number table method with 48 patients in the modified green dragon swaying its tail group(group special manipulation, SM group for short) and 47 patients in the common acupuncture group(group convention needling, CN group for short), and different acupuncture manipulations were applied in the two groups. Internationally recognized Simplified Mc Gill Pain Questionnaire(SF-MPQ) scale used for description and measurement of pain was applied to evaluate the pain degree, including pain rating index(PRI), visnal analogue scale(VAS)and present pain intensity(PPI). The index of severity for osteoarthritis(ISOA) was adopted for evaluation of clinical efficacy. Results(1) In SM group, the scores of PRI, VAS and PPI were 6.63±4.67, 2.23±1.45 and 0.65±1.32, respectively, after treatment, and in CN group, the scores of PRI, VAS and PPI were 13.32±7.96, 4.34±1.79 and 2.28±1.21, respectively, the scores decreased in the two groups after treatment(all P〈0.05), and the improvement in SM group was superior to that in CN group(all P〈0.01).(2) The clinical cure rate in SM group was 52.08%, and the total effective rate was 97.92%, the clinical cure rate in CN group was 25.53%, and the total effective rate was 85.10%. The comparison of clinical cure rate in the two groups showed that P〈0.01. Conclusion The SM group is obviously superior to CN group in the improvement of overall rating of pain of patients. It is indicated that modified green dragon swaying its tail acupuncture therapy can effectively relieve the pain of patients with knee osteoarthritis, which was worthy of popularization and application with definite clinical efficacy
文摘Conventional Bāliáo(八髎) was used to treat constipation,green dragon swaying its tail and white tiger shaking its head manipulation was applied and sound effect was found.
基金This work was supported in part by the Natural Science Foundation of China under Grant 62203461 and Grant 62203365in part by the Postdoctoral Science Foundation of China under Grant No.2020M683736,in part by the Teaching Reform Project of Higher Education in Heilongjiang Province under Grant Nos.SJGY20210456 and SJGY20210457in part by the Natural Science Foundation of Heilongjiang Province of China under Grant No.LH2021F038,and in part by the Graduate Academic Innovation Project of Harbin Normal University under Grant Nos.HSDSSCX2022-17,HSDSSCX2022-18 and HSDSSCX2022-19。
文摘A liquid launch vehicle is an important carrier in aviation,and its regular operation is essential to maintain space security.In the safety assessment of fluid launch vehicle body structure,it is necessary to ensure that the assessmentmodel can learn self-response rules from various uncertain data and not differently to provide a traceable and interpretable assessment process.Therefore,a belief rule base with interpretability(BRB-i)assessment method of liquid launch vehicle structure safety status combines data and knowledge.Moreover,an innovative whale optimization algorithm with interpretable constraints is proposed.The experiments are carried out based on the liquid launch vehicle safety experiment platform,and the information on the safety status of the liquid launch vehicle is obtained by monitoring the detection indicators under the simulation platform.The MSEs of the proposed model are 3.8000e-03,1.3000e-03,2.1000e-03,and 1.8936e-04 for 25%,45%,65%,and 84%of the training samples,respectively.It can be seen that the proposed model also shows a better ability to handle small sample data.Meanwhile,the belief distribution of the BRB-i model output has a high fitting trend with the belief distribution of the expert knowledge settings,which indicates the interpretability of the BRB-i model.Experimental results show that,compared with other methods,the BRB-i model guarantees the model’s interpretability and the high precision of experimental results.
文摘Arc spraying with the cored wires was applied to deposit FeMnCr/Cr3C2 coatings on low carbon steel substrates, namely FM1, FM2 and FM3. Thermal shock resistances of the coatings were investigated to assess the influence of Cr3C2 content on thermal shock resistance. Characteristics of the coatings under thermal cycling test were studied by optical microscopy, field emission scanning electron microscope (FE-SEM) and energy dispersion spectrum (EDS), X-ray diffraction (XRD). The experimental results show that hardness of the coatings increases, bonding strength decreases slightly with increase of the Cr3C2 content of the coatings. As a result, FM2 coating possesses the best thermal shock resistance, attributing to its better thermal expansion matches and wettability than those of FM3 coating, less oxide rate than that of FM1 coating restraining from cracks formation and propagation in coatings.
文摘In this paper, the influence depths of all levels of wind power produced waves are reckoned according to the measured swaying degree when a submarine meets with a force 11 strong tropical storm and has to submerge; Then the minimum submergence depth is given when a submarine is faced with weather systems with force ≥ 6 wind and the swaying degree of less than 12 degree is assured as reference for a submarine working and sailing in big strong winds and waves.
文摘The second order effect is the interaction between the vertical load and the deformation in a vertically forced element. In order to deduce a more brief but practical method, which has considered the second order effect in a sway frame, some factors which affect the second order deformation in a sway frame should be generalized based on a more accurate method. Nonlinear finite element is adopted in this paper, and according to this theory, a program, which can calculate the inner force and the deformation of the sway frame considering the second order effects is coded.
文摘In this paper, the transportation mode of tube during the immersed tunnel engineering in Yangtze River incorporated, mathematical models of the combination of the tube and four barges are established when it is towed by a tugboat through an elastic rope and pushed by two pushers. Based on evaluating the hydrodynamic derivatives by regressive formula, the simulations and analysis of the whole maneuvering motion course are accomplished. They include sway and yaw motion simulation of the combination and prediction of maneuvering motion such as turning circles of different rudder angle under the condition of being pushed by two pushers. The coincidence of the prediction with the results of model test is good.
文摘The passive anti-rolling tank is one of important ship stabilizers widely used today. But at present, research of the tank is most aimed at its rolling movement. In this paper, the influence of sway motion on the passive anti-rolling tank is considered, the mathematical model of "ship-passive antl-rolling tank" system coupled with sway motion is developed basing on the U-shaped passive anti-rolling tank theory. Both simulation results and experimental data indicate that it is necessary to consider the influence of sway motion on the anti-rolling tank, which is more agreeable to the actual circumstance.
基金Grants-in-Aid for Scientific Research from YOKOYAMA Foundation for Clinical Pharmacologya Grant-in-Aid from the Center of Excellence (COE) from the Ministry of Education, Culture, Sports, Science and Technology of JapanGrant-in-Aid from the Ministry of Education, Culture, Sports, Science and Technology of Japan No. 17590470
文摘AIM: To examine whether the sedative effects assessed by psychomotor tests would depend on the cytochrome P450 (CYP ) 2C19 genotypes after an infusion regimen of diazepam commonly used forgastrointestinal endoscopy in Japan. METHODS: Fifteen healthy Japanese volunteers consisting of three different CYP2C19 genotype groups underwent a critical ? icker fusion test, an eye movement analysis and a postural sway test as a test for physical sedative effects, and a visual analog scale (VAS) symptom assessment method as a test for mental sedative effects during the 336 h period after the intravenous infusion of diazepam (5 mg). RESULTS: The physical sedative effects assessed by the critical flicker test continued for 1 h (t values of 5 min, 30 min and 60 min later: 4.35, 5.00 and 3.19, respectively) and those by the moving radial area of a postural sway test continued for 3 h (t values of 5 h, 30 h, 60 min and 3 h later: -4.05, -3.42, -2.17 and -2.58, respectively), which changed significantly compared with the baseline level before infusion (P < 0.05). On the other hand, the mental sedative effects by the VAS method improved within 1 h. The CYP2C19 genotype-dependent differences in the postinfusion sedative effects were not observed in any of the four psychomotor function tests. CONCLUSION: With the psychomotor tests, the objective sedative effects of diazepam continued for 1 h to 3 h irrespective of CYP2C19 genotype status and the subjective sedative symptoms improved within 1 h. Up to 3 h of clinical care appears to be required after the infusion of diazepam, although patients feel subjectively improved.
基金supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MEST) (No. 2008-0060153)
文摘The sloshing flows in a LNG cargo tank model (1/50 scale) of a ship are measured by an embedded pano- ramicPIV system. The measurement system consists of a Nd-Yag laser(120mJ, 15Hz), two cameras(lk x lk) and a host computer. Four experimental cases were tested for the tank model, in which swaying motions are made by a 6 DOF-motion platform. The amplitudes of swaying are 9.76mm and 29.29mm, and the swaying frequencies are 0.633Hz and 0.828Hz. The measurement regions are the vertical plane 50ram away from the front wall of the tank where a pump tower is installed. It was verified that the flow patterns of the sloshing are similar to each other when the swaying amplitudes are similar.
基金Project supported by the National Marine Public Welfare Research Project of China(Grant No.201005002)
文摘An improved meshing method based on Fluent is used to update the computational meshes in solving the Navier-Stokes (N-S) equations for viscous and incompressible free surface flows with the volume of fluid (VOF) method. To maintain the mesh quality when updating meshes for a moving structure, the computational domain is separated into several parts and each part corre- sponds to a specific type of body motion. The numerical results of the interaction between the floating body and the regular waves agree well with the experimental data. A total of eight typical motion types are simulated separately to understand the correlation between the motion types and the wave transmission as well as the forces acting on the floating body. Numerical experiments show that the wave transmission increases in the case of sway and heave motions and decreases in the case of pitch motion as compared with the stationary case. It is also found that the sway motion reduces the horizontal wave force acting on the floating body, while the heave motion enhances the vertical wave force.