We have prepared the 2-（quinolin-8-yloxy）-acetic acid and characterized it by infrared and Raman spectroscopies in the solid phase. The Density Functional Theory （DFT） method, together with the 6-31G^＊ and 6-311...We have prepared the 2-（quinolin-8-yloxy）-acetic acid and characterized it by infrared and Raman spectroscopies in the solid phase. The Density Functional Theory （DFT） method, together with the 6-31G^＊ and 6-311＋＋ G^＊＊ basis sets, show that three stable molecules, for the anhydrous and monohydrated compounds were theoretically determined in the gas phase, and that probably the two more stable conformations are present in the solid phase of the monohydrated compound. The harmonic vibrational wavenumbers for the optimized geometries were calculated at B3LYP/6-31G^＊and B3LYP/6-311＋＋G^＊＊ levels. For a complete assignment of all the observed bands in the vibrational spectra the DFT calculations were combined with Pulay＇s scaled quantum mechanical force field （SQMFF） methodology in order to fit the theoretical Wavenumber values to the experimental ones. The characteristics of the electronic delocalization of all structures of both forms were performed by using natural bond orbital （NBO）, while the corresponding topological properties of electronic charge density are analysed by employing Bader＇s atoms in molecules theory （AIM）.展开更多
The flexible pipe bend can not only reduce the structural vibration and fluid noise in pipeline, but also realize the flexible connection of a horizontal line and a vertical line and compensate the displacement of thr...The flexible pipe bend can not only reduce the structural vibration and fluid noise in pipeline, but also realize the flexible connection of a horizontal line and a vertical line and compensate the displacement of three dimensions produced by the shock or vibration of pipeline in the special situations. Up to now, little attention has been paid to study the flexible pipe bend applied in the pipeline of medium or high pressure, because no appropriate framework materials can be used to reinforce it which must endure the burst pressure higher than 10 MPa. The investigation shows that it is possible to produce the flexible pipe bend of medium or high pressure if such fibers with high performance as Kevlar fibers are used to be its reinforced materials. However, its structural designing theory, manufacturing technology and measuring techniques aren't yet perfect and systematic, which leads to the instability of the performance of products. Furthermore, few references about its research can be seen. Therefore, it is necessary to systematically and thoroughly develop the structural designing theory, manufacture technology and measuring techniques of flexible pipe bend.展开更多
The micro-cantilever beam with a twin long period optic fiber grating sensitive to the strain and the vibration is designed to use as the sensor head.The micro-displacement of wavelength caused by strain or vibration ...The micro-cantilever beam with a twin long period optic fiber grating sensitive to the strain and the vibration is designed to use as the sensor head.The micro-displacement of wavelength caused by strain or vibration is amplified in the system.Special cladding material is used to eliminate the interference brougth about the temperature.The designing structure is enabled to detect the micro-information.展开更多
The ultrafast dynamics of benzaldehyde upon 260, 271, 284, and 287 nm excitations have been studied by femtosecond pinup-probe time-of-flight mass spectrometry. A bi-exponential decay component model was applied to fi...The ultrafast dynamics of benzaldehyde upon 260, 271, 284, and 287 nm excitations have been studied by femtosecond pinup-probe time-of-flight mass spectrometry. A bi-exponential decay component model was applied to fit the transient profiles of benzaldehyde ions and fragment ions. At the S2 origin, the first decay of the component was attributed to the internal conversion to the high vibrational levels of S1 state. Lifetimes of the first component decreased with increasing vibrational energy, due to the influence of high density of the vibrational levels. The second decay was assigned to the vibrational relaxation of the S1 whose lifetime was about 600 fs. Upon 287 nm excitation, the first decay became ultra-short （-56 fs） which was taken for the intersystem cross from S1 to T2, while the second decay component was attributed to the vibrational relaxation. The pump-probe transient of fragment was also studied with the different probe intensity at 284 nm pump.展开更多
Power ultrasound is finding widespread applications in assisting conventional processes yielding products of better quality at lower processing power and temperature. Transmission of ultrasound is known to be affected...Power ultrasound is finding widespread applications in assisting conventional processes yielding products of better quality at lower processing power and temperature. Transmission of ultrasound is known to be affected by the boundaries between layers of different materials or same material but in different states （solid or liquid or gas）. This paper investigates the effects of ultrasound （US） on the surface of the solidified weld which has been subjected to ultrasonic vibrations of 20 kHz frequency during laser welding. Vibrations due to ultrasound normally exert a very high force which is usually hundred or thousand times the gravity. The transverse waves will also cause movement of molten material in the weld. As the surface of the weld beads were of interest and not the mechanical properties and the microstructure, investigation of bead on plate welds were found to be sufficient. High carbon steel plate was held at one end by the ultrasonic horn through which ultrasound was injected. A bead on plate weld using a CO2 laser （1 kW） was then performed along the center of the plate using three different welding speeds namely, 400, 1200 and 2000 mm per minute. The ultrasonic powers selected were 3 W and 6 W respectively for each welding speed as higher acoustical power was causing ejection of molten metal from the pool during welding. 3D surface measurements and analysis were then made on a section of length 20 mm using a Talysurf machine. The results show that the surface of the weld was affected to different extent depending on the positions being considered in the weld. Some regions were similar to the reference weld whereas some specific regions were heavily disrupted with deep valleys followed by high peak/s. This shows that US vibration of weld pools, even at very small acoustical power, is a more complex problem than other similar processes such as casting because of the very small volume of molten metal involved.展开更多
An alternative scheme is proposed for one-step generation of multiparticle cluster state with trapped ionsin thermal motion.In this scheme,the ions are simultaneously illuminated by a standing-wave laser tuned to the ...An alternative scheme is proposed for one-step generation of multiparticle cluster state with trapped ionsin thermal motion.In this scheme,the ions are simultaneously illuminated by a standing-wave laser tuned to the carrier.During the operations,the vibrational mode is virtually excited,thus the quantum operations are insensitive to theheating.It is shown that the high fidelity multiparticle entanglement could be generated in just one step even includingthe small fluctuations of parameters.In addition,the ion does not need to be exactly positioned at the node of thestanding wave,which is also important from the viewpoint of experiment.展开更多
文摘We have prepared the 2-（quinolin-8-yloxy）-acetic acid and characterized it by infrared and Raman spectroscopies in the solid phase. The Density Functional Theory （DFT） method, together with the 6-31G^＊ and 6-311＋＋ G^＊＊ basis sets, show that three stable molecules, for the anhydrous and monohydrated compounds were theoretically determined in the gas phase, and that probably the two more stable conformations are present in the solid phase of the monohydrated compound. The harmonic vibrational wavenumbers for the optimized geometries were calculated at B3LYP/6-31G^＊and B3LYP/6-311＋＋G^＊＊ levels. For a complete assignment of all the observed bands in the vibrational spectra the DFT calculations were combined with Pulay＇s scaled quantum mechanical force field （SQMFF） methodology in order to fit the theoretical Wavenumber values to the experimental ones. The characteristics of the electronic delocalization of all structures of both forms were performed by using natural bond orbital （NBO）, while the corresponding topological properties of electronic charge density are analysed by employing Bader＇s atoms in molecules theory （AIM）.
文摘The flexible pipe bend can not only reduce the structural vibration and fluid noise in pipeline, but also realize the flexible connection of a horizontal line and a vertical line and compensate the displacement of three dimensions produced by the shock or vibration of pipeline in the special situations. Up to now, little attention has been paid to study the flexible pipe bend applied in the pipeline of medium or high pressure, because no appropriate framework materials can be used to reinforce it which must endure the burst pressure higher than 10 MPa. The investigation shows that it is possible to produce the flexible pipe bend of medium or high pressure if such fibers with high performance as Kevlar fibers are used to be its reinforced materials. However, its structural designing theory, manufacturing technology and measuring techniques aren't yet perfect and systematic, which leads to the instability of the performance of products. Furthermore, few references about its research can be seen. Therefore, it is necessary to systematically and thoroughly develop the structural designing theory, manufacture technology and measuring techniques of flexible pipe bend.
文摘The micro-cantilever beam with a twin long period optic fiber grating sensitive to the strain and the vibration is designed to use as the sensor head.The micro-displacement of wavelength caused by strain or vibration is amplified in the system.Special cladding material is used to eliminate the interference brougth about the temperature.The designing structure is enabled to detect the micro-information.
基金V. ACKNOWLEDGMENT This work was supported by the National Natural Science Foundation of China （No.20633070 and No.20473090）.
文摘The ultrafast dynamics of benzaldehyde upon 260, 271, 284, and 287 nm excitations have been studied by femtosecond pinup-probe time-of-flight mass spectrometry. A bi-exponential decay component model was applied to fit the transient profiles of benzaldehyde ions and fragment ions. At the S2 origin, the first decay of the component was attributed to the internal conversion to the high vibrational levels of S1 state. Lifetimes of the first component decreased with increasing vibrational energy, due to the influence of high density of the vibrational levels. The second decay was assigned to the vibrational relaxation of the S1 whose lifetime was about 600 fs. Upon 287 nm excitation, the first decay became ultra-short （-56 fs） which was taken for the intersystem cross from S1 to T2, while the second decay component was attributed to the vibrational relaxation. The pump-probe transient of fragment was also studied with the different probe intensity at 284 nm pump.
文摘Power ultrasound is finding widespread applications in assisting conventional processes yielding products of better quality at lower processing power and temperature. Transmission of ultrasound is known to be affected by the boundaries between layers of different materials or same material but in different states （solid or liquid or gas）. This paper investigates the effects of ultrasound （US） on the surface of the solidified weld which has been subjected to ultrasonic vibrations of 20 kHz frequency during laser welding. Vibrations due to ultrasound normally exert a very high force which is usually hundred or thousand times the gravity. The transverse waves will also cause movement of molten material in the weld. As the surface of the weld beads were of interest and not the mechanical properties and the microstructure, investigation of bead on plate welds were found to be sufficient. High carbon steel plate was held at one end by the ultrasonic horn through which ultrasound was injected. A bead on plate weld using a CO2 laser （1 kW） was then performed along the center of the plate using three different welding speeds namely, 400, 1200 and 2000 mm per minute. The ultrasonic powers selected were 3 W and 6 W respectively for each welding speed as higher acoustical power was causing ejection of molten metal from the pool during welding. 3D surface measurements and analysis were then made on a section of length 20 mm using a Talysurf machine. The results show that the surface of the weld was affected to different extent depending on the positions being considered in the weld. Some regions were similar to the reference weld whereas some specific regions were heavily disrupted with deep valleys followed by high peak/s. This shows that US vibration of weld pools, even at very small acoustical power, is a more complex problem than other similar processes such as casting because of the very small volume of molten metal involved.
基金Supported by the National Natural Science Foundation of China under Grant Nos. 10704017, 11074036National Fundamental Research Program of China under Grant No. 2007CB936300
文摘An alternative scheme is proposed for one-step generation of multiparticle cluster state with trapped ionsin thermal motion.In this scheme,the ions are simultaneously illuminated by a standing-wave laser tuned to the carrier.During the operations,the vibrational mode is virtually excited,thus the quantum operations are insensitive to theheating.It is shown that the high fidelity multiparticle entanglement could be generated in just one step even includingthe small fluctuations of parameters.In addition,the ion does not need to be exactly positioned at the node of thestanding wave,which is also important from the viewpoint of experiment.
