A synchronous electronic let-off and take-up device isdesigned.The device is controlled by a single-chipcomputer and driven by two step motors.It has somefunctions such as keeping the warp tension constant dur-ing the...A synchronous electronic let-off and take-up device isdesigned.The device is controlled by a single-chipcomputer and driven by two step motors.It has somefunctions such as keeping the warp tension constant dur-ing the weaving instant,releasing the warp tension whenloom is stopping and straining warp when loom is start-ing.By means of these functions,the stop mark of thewoven fabrics is eliminated.In addition,this device canapply to weaving variant-pick-density fabrics.展开更多
A new video-based measurement is proposed to collect and investigate traffic flow parameters. The output of the measurement is velocity-headway distance data pairs. Because density can be directly acquired by the reci...A new video-based measurement is proposed to collect and investigate traffic flow parameters. The output of the measurement is velocity-headway distance data pairs. Because density can be directly acquired by the reciprocal of headway distance, the data pairs have the advantage of better simultaneity than those from common detectors. By now, over 33 000 pairs of data have been collected from two road sections in the cities of Shanghai and Zhengzhou. Through analyzing the video files recording traffic movements on urban expressways, the following issues are studied：laws of vehicle velocity changing with headway distance, proportions of di0erent driving behaviors in the traffic system, and characteristics of traffic flow in snowy days. The results show that the real road traffic is very complex, and factors such as location and climate need to be taken into consideration in the formation of traffic flow models.展开更多
This paper analyzed the characteristics of welding solidification crack of stainless steels,and clearly re- vealed the the of the deformation in the molten - the pool and the solidification shrinkage on the stress -...This paper analyzed the characteristics of welding solidification crack of stainless steels,and clearly re- vealed the the of the deformation in the molten - the pool and the solidification shrinkage on the stress - strain fields in the trail of molten - weld pool.Moreover, rheologic properties of the alloys in solid - liquid zone were also obtained by measuring the hading and unloading deform curves of the steels.As a result, a numerical model for simulation of stress - strain distributions of welding solidifi- cation crack was developed. On the basis of the model,the thesis simulated the driving force of solidifi- cation crack of stainless steels, that is, stress - strain fields in the trail of molten-weld pool with fi- nite element method.展开更多
The existing plastic forming equipment are mostly driven by traditional AC motors with long trans- mission chains, low efficiency, large size, low precision and poor dynamic response are the common disadvantages. In o...The existing plastic forming equipment are mostly driven by traditional AC motors with long trans- mission chains, low efficiency, large size, low precision and poor dynamic response are the common disadvantages. In order to realize high performance forming processes, the driving device should be improved, especially for com- plicated processing motions. Based on electric servo direct drive technology, a novel AC servo rotating and linear composite driving device is proposed, which features implementing both spindle rotation and feed motion with- out transmission, so that compact structure and precise control can be achieved. Flux switching topology is employed in the rotating drive component for strong robustness, and fractional slot is employed in the linear direct drive component for large force capability. Then the mechanical structure for compositing rotation and linear motion is designed. A device prototype is manufactured, machining of each component and the whole assembly are presented respectively. Commercial servo amplifiers are utilized to construct the control system of the proposed device. To validate the effectiveness of the proposed composite driving device, experimental study on thedynamic test benches are conducted. The results indicate that the output torque can attain to 420 N-m and the dynamic tracking errors are less than about 0.3 rad in the rotating drive, the dynamic tracking errors are less than about 1.6 mm in the linear feed. The proposed research provides a method to construct high efficiency and accu- racy direct driving device in plastic forming equipment.展开更多
Using the ligand bis（3-（1H-imidazol-1-yl）-1-phenylpropan-1-one） L, two novel complexes [CuL2（ph））]·H2O 1 and [ZnL2（tp）] 2 （ph = phthalic acid, tp = terephthalic acid） have been synthesized and their cr...Using the ligand bis（3-（1H-imidazol-1-yl）-1-phenylpropan-1-one） L, two novel complexes [CuL2（ph））]·H2O 1 and [ZnL2（tp）] 2 （ph = phthalic acid, tp = terephthalic acid） have been synthesized and their crystal structures were determined by single-crystal X-ray diffraction analysis. Crystal data for 1： triclinic, space group P1^-, a = 9.4300（17）, b = 12.148（2）, c = 13.721（2） A, a = 109.620（2）,β = 94.351（2）, y = 94.830（2）°, C32H30N4O7Cu, Mr = 646.14, V= 1466.2（4） A^3, Z = 2, Dc = 1.464 g/cm3, It（MoKa） = 0.801 mm^-1, F（000） = 670, the final R = 0.0337 and wR = 0.0859 for 5122 observed reflections with I 〉 2σ（I）, And those for 2： monoclinic, space group P2/n, a = 7.1866（11）, b = 14.144（2）, c = 14.407（2）/k, β = 101.427（2）°, C32H28N4O6Zn, Mr = 629.95, V = 1435.4（4） A3, Z = 2, Dc = 1.457 g/cm3, μ（MoKa） = 0.908 mm^-1, F（000） = 652, the final R = 0.0438 and wR= 0.0821 for 2546 observed reflections with I〉 2σ（I）. In 1 and 2, ph or tp ligauds bridge the six-coordinated copper（Ⅱ） or four-coordinated zinc（Ⅱ） ions forming 1D zigzag chains while L ligands act as the terminal monodentate ligand. It is noted that weak non-classical C-H…O plays the important and dominating roles in the formation of 2D supramolecular architectures of 1, but in 2 non-classical C-H…O and aromatic π…π Stacking interactions are quite important and play dominant roles in the self-assembly of 2D supramolecular architectures.展开更多
A novel vertical actuator based on electrowetting on dielectric （EWOD） was designed, analyzed and simulated. Modeling results indicated that the vertical driving force of the actuator obeyed a second order polynomia...A novel vertical actuator based on electrowetting on dielectric （EWOD） was designed, analyzed and simulated. Modeling results indicated that the vertical driving force of the actuator obeyed a second order polynomial of applied voltage, which was verified by Covent_ware 2006. As a resuit, the vertical driving force of the EWOD actuator with a 1.1 nL droplet and a 1.75 μm thick polymer was about 0.5 μN under an applied voltage 100V which was comparable to that of the electrostatic actuators. Moreover, the noise from plane forces we analyzed and simulated was very low. Therefore, we made a conclusion that the EWOD actuator can be used in MEMS transducer.展开更多
文摘A synchronous electronic let-off and take-up device isdesigned.The device is controlled by a single-chipcomputer and driven by two step motors.It has somefunctions such as keeping the warp tension constant dur-ing the weaving instant,releasing the warp tension whenloom is stopping and straining warp when loom is start-ing.By means of these functions,the stop mark of thewoven fabrics is eliminated.In addition,this device canapply to weaving variant-pick-density fabrics.
基金supported by the National Natural Science Foundation of China (10772050)
文摘A new video-based measurement is proposed to collect and investigate traffic flow parameters. The output of the measurement is velocity-headway distance data pairs. Because density can be directly acquired by the reciprocal of headway distance, the data pairs have the advantage of better simultaneity than those from common detectors. By now, over 33 000 pairs of data have been collected from two road sections in the cities of Shanghai and Zhengzhou. Through analyzing the video files recording traffic movements on urban expressways, the following issues are studied：laws of vehicle velocity changing with headway distance, proportions of di0erent driving behaviors in the traffic system, and characteristics of traffic flow in snowy days. The results show that the real road traffic is very complex, and factors such as location and climate need to be taken into consideration in the formation of traffic flow models.
文摘This paper analyzed the characteristics of welding solidification crack of stainless steels,and clearly re- vealed the the of the deformation in the molten - the pool and the solidification shrinkage on the stress - strain fields in the trail of molten - weld pool.Moreover, rheologic properties of the alloys in solid - liquid zone were also obtained by measuring the hading and unloading deform curves of the steels.As a result, a numerical model for simulation of stress - strain distributions of welding solidifi- cation crack was developed. On the basis of the model,the thesis simulated the driving force of solidifi- cation crack of stainless steels, that is, stress - strain fields in the trail of molten-weld pool with fi- nite element method.
基金Supported by National Natural Science Foundation of China(Grant No.51335009)Major National Science and Technology Project of China(Grant No.2011ZX04001-011)
文摘The existing plastic forming equipment are mostly driven by traditional AC motors with long trans- mission chains, low efficiency, large size, low precision and poor dynamic response are the common disadvantages. In order to realize high performance forming processes, the driving device should be improved, especially for com- plicated processing motions. Based on electric servo direct drive technology, a novel AC servo rotating and linear composite driving device is proposed, which features implementing both spindle rotation and feed motion with- out transmission, so that compact structure and precise control can be achieved. Flux switching topology is employed in the rotating drive component for strong robustness, and fractional slot is employed in the linear direct drive component for large force capability. Then the mechanical structure for compositing rotation and linear motion is designed. A device prototype is manufactured, machining of each component and the whole assembly are presented respectively. Commercial servo amplifiers are utilized to construct the control system of the proposed device. To validate the effectiveness of the proposed composite driving device, experimental study on thedynamic test benches are conducted. The results indicate that the output torque can attain to 420 N-m and the dynamic tracking errors are less than about 0.3 rad in the rotating drive, the dynamic tracking errors are less than about 1.6 mm in the linear feed. The proposed research provides a method to construct high efficiency and accu- racy direct driving device in plastic forming equipment.
基金Fund for Central Universities (ZXH2009D011)Natural Science Foundation of Tianjin (09JCYBJC04200)+1 种基金National Natural Science Foundation of China Civil Aviation Administration of China (61079010) Scientific Research Foundation of Civil Aviation University of China (2011KYS05)
文摘Using the ligand bis（3-（1H-imidazol-1-yl）-1-phenylpropan-1-one） L, two novel complexes [CuL2（ph））]·H2O 1 and [ZnL2（tp）] 2 （ph = phthalic acid, tp = terephthalic acid） have been synthesized and their crystal structures were determined by single-crystal X-ray diffraction analysis. Crystal data for 1： triclinic, space group P1^-, a = 9.4300（17）, b = 12.148（2）, c = 13.721（2） A, a = 109.620（2）,β = 94.351（2）, y = 94.830（2）°, C32H30N4O7Cu, Mr = 646.14, V= 1466.2（4） A^3, Z = 2, Dc = 1.464 g/cm3, It（MoKa） = 0.801 mm^-1, F（000） = 670, the final R = 0.0337 and wR = 0.0859 for 5122 observed reflections with I 〉 2σ（I）, And those for 2： monoclinic, space group P2/n, a = 7.1866（11）, b = 14.144（2）, c = 14.407（2）/k, β = 101.427（2）°, C32H28N4O6Zn, Mr = 629.95, V = 1435.4（4） A3, Z = 2, Dc = 1.457 g/cm3, μ（MoKa） = 0.908 mm^-1, F（000） = 652, the final R = 0.0438 and wR= 0.0821 for 2546 observed reflections with I〉 2σ（I）. In 1 and 2, ph or tp ligauds bridge the six-coordinated copper（Ⅱ） or four-coordinated zinc（Ⅱ） ions forming 1D zigzag chains while L ligands act as the terminal monodentate ligand. It is noted that weak non-classical C-H…O plays the important and dominating roles in the formation of 2D supramolecular architectures of 1, but in 2 non-classical C-H…O and aromatic π…π Stacking interactions are quite important and play dominant roles in the self-assembly of 2D supramolecular architectures.
文摘A novel vertical actuator based on electrowetting on dielectric （EWOD） was designed, analyzed and simulated. Modeling results indicated that the vertical driving force of the actuator obeyed a second order polynomial of applied voltage, which was verified by Covent_ware 2006. As a resuit, the vertical driving force of the EWOD actuator with a 1.1 nL droplet and a 1.75 μm thick polymer was about 0.5 μN under an applied voltage 100V which was comparable to that of the electrostatic actuators. Moreover, the noise from plane forces we analyzed and simulated was very low. Therefore, we made a conclusion that the EWOD actuator can be used in MEMS transducer.
