Separate characteristic of the tangential ultrasonic vibration assisted grinding (TUAG) machining is analyzed based on TUAG process, and a critical speed formula is given to correctly set the machining parameters to i...Separate characteristic of the tangential ultrasonic vibration assisted grinding (TUAG) machining is analyzed based on TUAG process, and a critical speed formula is given to correctly set the machining parameters to insure the separate characteristics of TUAG process. The critical speed is not only related to the ultrasonic vibration amplitude and frequency, but also to the grinding wheel velocity and the cutting point space, and the grinding force can be decreased during the TUAG process with separability. Grinding force experiments are conducted, and the experimental results are in good agreement with the theoretical results.展开更多
The particles suspending in liquid suffer acoustical radiation force from ultrasonic field. The force may cause particles movement and has special advantage to separate particles from liquid in Micro Electro Mechanica...The particles suspending in liquid suffer acoustical radiation force from ultrasonic field. The force may cause particles movement and has special advantage to separate particles from liquid in Micro Electro Mechanical Systems （MEMS）. It is important to improve the energy stored in liquid layer so as to increase separation ability for decreasing drive demand in MEMS. Resonance may hugely increase the magnitude and generally be employed in micro separator. The summits of admittance spectrum show the resonance frequencies. It may come from resonance in one layer or multi layers in micro separator. This paper studies the difference of energy stored in layers at each rein frequency. It provides the way to select the most effect separation frequency other than admittance spectrum.展开更多
The ultrasonic, magnetic and transport properties of Nd0.5Ca0.5Mn1-xAlxO3 （x=0, 0.03） were studied from 15 to 300 K. The temperature dependencies of resistivity and magnetization show that Nd0.5Ca0.5MnO3 undergoes a...The ultrasonic, magnetic and transport properties of Nd0.5Ca0.5Mn1-xAlxO3 （x=0, 0.03） were studied from 15 to 300 K. The temperature dependencies of resistivity and magnetization show that Nd0.5Ca0.5MnO3 undergoes a charge ordering transition at TCO-257 K. An obvious softening of the longitudinal sound velocity above TCO and a dramatic stiffening below Too accompanied by an attenuation peak were observed. These features imply a strong electron phonom interaction via the Jahn-Teller effect iu the sample, Another broad attenuation peak was observed at around Tp-80 K. This anomaly is attributed to the phase separtion between the antiferromagnetic （AFM） and paramagnetic （PM） phases and gives a direct evidence for spin-phonon coupling in the compound. For the x=0.03 sample, both the minimum of sound velocity and attenuation peaks shift to a lower temperature. The results indicate that the charge ordering and CE-type AFM state in Nd0.5Ca0.5MnO3 are both partially suppressed by replacing Mn with A1.展开更多
The feasibility of using ultrasound to enhance the performance of de-sulphurization and de-ashing during slime flotation was investigated. The Setararn C80 calorimeter, the contact angle gauge DCAT21 and an electropho...The feasibility of using ultrasound to enhance the performance of de-sulphurization and de-ashing during slime flotation was investigated. The Setararn C80 calorimeter, the contact angle gauge DCAT21 and an electrophoresis apparatus were used to study the surface nature of coal, pyrite and refuse before and after ultrasonic conditioning. The yield, ash and sulfur contents of equally sized coal slimes were also measured before and after ultrasonic conditioning. The results show that ultrasonic conditioning can drive the separation of pyrite and refuse from coal. After ultrasonic conditioning the hydrophobicity of coal and hydrophilicity of pyrite and refuse increase. The perfect index of flotation, the perfect index of de-sulphurization and the percentage of de-sulphurization increase by 22.51%, 25.36% and 2.49%, respectively. This study shows that ultrasonic conditioning can enhance the performance of de-sulphurization and de-ashing of coal flotation methods.展开更多
In this paper, we report a high-perfornmnce P3HT/PCBM bulk-heterojunction solar cell with a power conversion efficiency of 4.85% fabricated by adjusting the polymer crystallinity and nanoscale phase separation using a...In this paper, we report a high-perfornmnce P3HT/PCBM bulk-heterojunction solar cell with a power conversion efficiency of 4.85% fabricated by adjusting the polymer crystallinity and nanoscale phase separation using an ultrasonic irradiation mixing approach for the polymer. The grazing incidence X-ray diffraction, UV/Vis spectroscopic, and atomic force microscopic measurement results for the P3HT/PCBM blend films reveal that the P3HT/PCBM film fabricated by ultrasonic irradiation mixing of the P3HT and PCBM solutions for 10 min has a higher degree of crystallinity, a higher absorption efficiency, and better phase separation, which together account for the higher charge transport properties and photovoltaic cell performance.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.50575127)
文摘Separate characteristic of the tangential ultrasonic vibration assisted grinding (TUAG) machining is analyzed based on TUAG process, and a critical speed formula is given to correctly set the machining parameters to insure the separate characteristics of TUAG process. The critical speed is not only related to the ultrasonic vibration amplitude and frequency, but also to the grinding wheel velocity and the cutting point space, and the grinding force can be decreased during the TUAG process with separability. Grinding force experiments are conducted, and the experimental results are in good agreement with the theoretical results.
文摘The particles suspending in liquid suffer acoustical radiation force from ultrasonic field. The force may cause particles movement and has special advantage to separate particles from liquid in Micro Electro Mechanical Systems （MEMS）. It is important to improve the energy stored in liquid layer so as to increase separation ability for decreasing drive demand in MEMS. Resonance may hugely increase the magnitude and generally be employed in micro separator. The summits of admittance spectrum show the resonance frequencies. It may come from resonance in one layer or multi layers in micro separator. This paper studies the difference of energy stored in layers at each rein frequency. It provides the way to select the most effect separation frequency other than admittance spectrum.
基金supported by the National Natural Science Foundation of China(No.10274075)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20030358056).
文摘The ultrasonic, magnetic and transport properties of Nd0.5Ca0.5Mn1-xAlxO3 （x=0, 0.03） were studied from 15 to 300 K. The temperature dependencies of resistivity and magnetization show that Nd0.5Ca0.5MnO3 undergoes a charge ordering transition at TCO-257 K. An obvious softening of the longitudinal sound velocity above TCO and a dramatic stiffening below Too accompanied by an attenuation peak were observed. These features imply a strong electron phonom interaction via the Jahn-Teller effect iu the sample, Another broad attenuation peak was observed at around Tp-80 K. This anomaly is attributed to the phase separtion between the antiferromagnetic （AFM） and paramagnetic （PM） phases and gives a direct evidence for spin-phonon coupling in the compound. For the x=0.03 sample, both the minimum of sound velocity and attenuation peaks shift to a lower temperature. The results indicate that the charge ordering and CE-type AFM state in Nd0.5Ca0.5MnO3 are both partially suppressed by replacing Mn with A1.
基金Projects 50274036 supported by the National Natural Science Foundation of China1055G039 by the Mainstay Teacher Originality Innovation Plan Foundation of the Education Department of Heilongjiang Province.
文摘The feasibility of using ultrasound to enhance the performance of de-sulphurization and de-ashing during slime flotation was investigated. The Setararn C80 calorimeter, the contact angle gauge DCAT21 and an electrophoresis apparatus were used to study the surface nature of coal, pyrite and refuse before and after ultrasonic conditioning. The yield, ash and sulfur contents of equally sized coal slimes were also measured before and after ultrasonic conditioning. The results show that ultrasonic conditioning can drive the separation of pyrite and refuse from coal. After ultrasonic conditioning the hydrophobicity of coal and hydrophilicity of pyrite and refuse increase. The perfect index of flotation, the perfect index of de-sulphurization and the percentage of de-sulphurization increase by 22.51%, 25.36% and 2.49%, respectively. This study shows that ultrasonic conditioning can enhance the performance of de-sulphurization and de-ashing of coal flotation methods.
基金Project supported by the National Natural Science Foundation of China (Grant No. 60871007)
文摘In this paper, we report a high-perfornmnce P3HT/PCBM bulk-heterojunction solar cell with a power conversion efficiency of 4.85% fabricated by adjusting the polymer crystallinity and nanoscale phase separation using an ultrasonic irradiation mixing approach for the polymer. The grazing incidence X-ray diffraction, UV/Vis spectroscopic, and atomic force microscopic measurement results for the P3HT/PCBM blend films reveal that the P3HT/PCBM film fabricated by ultrasonic irradiation mixing of the P3HT and PCBM solutions for 10 min has a higher degree of crystallinity, a higher absorption efficiency, and better phase separation, which together account for the higher charge transport properties and photovoltaic cell performance.
