In order to delay or eliminate the occurrence and expansion of the reflective cracking in the asphalt concrete overlay on old cement concrete pavement, an epoxy asphalt geogrid stress-absorbing layer( EAGSAL) was de...In order to delay or eliminate the occurrence and expansion of the reflective cracking in the asphalt concrete overlay on old cement concrete pavement, an epoxy asphalt geogrid stress-absorbing layer( EAGSAL) was designed. The EAGSAL consists of epoxy asphalt and fiberglass geogrid. The pull-out test, skewshearing test, bending beam test and fatigue test were conducted to evaluate the performance of the EAGSAL and a traditional stress-absorbing layer( TSAL). The results showthat the adhesive performance, shear performance, bending strength and fatigue performance of the EAGSAL with an optimal spraying volume of epoxy asphalt are better than those of optimally designed TSAL, and the maximum bending strain of the EAGSAL is very close to that of the TSAL. The EAGSAL has superior performance in reflective cracking resistance.Moreover, the EAGSAL with the optimal spraying volume of approximately 2. 0 L m^2 is thinner and lighter than the TSAL,which can decrease the thickness and improve the bearing ability of the whole pavement structure.展开更多
A crossed molecular beams, state-to-state scattering study was carried out on the F+H2→HF+H reaction at the collision energy of 5.02 kJ/mol, using the highly sensitive H atom Rydberg tagging time-of-flight method. ...A crossed molecular beams, state-to-state scattering study was carried out on the F+H2→HF+H reaction at the collision energy of 5.02 kJ/mol, using the highly sensitive H atom Rydberg tagging time-of-flight method. All the peaks in the TOF spectra can be clearly assigned to the ro-vibrational structures of the HF product. The forward scattering of the HF product at v′=3 has been observed. The small forward scattering of the HF product at v′=2 has also been detected. Detailed theoretical analysis is required in order to fully understand the dynamical origin of these forward scattering products at this high collision energy.展开更多
Taking into consideration the disadvantage of Balanced Scorecard(BSC)not being able to reflect time delay,nonlinear problems of causal relationship and being lack of effective simulation,we combined it with the charac...Taking into consideration the disadvantage of Balanced Scorecard(BSC)not being able to reflect time delay,nonlinear problems of causal relationship and being lack of effective simulation,we combined it with the characteristics of the System Dynamics(SD).Basing on the background of manufacturing enterprises,through SD integrating with the BSC we established a new performance evaluation method-SD-BSC method to overcome the disadvantage of BSC.A performance evaluation model of SD-BSC is provided and the simulation results are analyzed which show different production policies will lead to different customer's satisfaction degrees.The SD-BSC dynamic performance evaluation method can reflect dynamic,complex causal feedback relationship and time delay,so it compensates for the disadvantage of traditional financial performance evaluation method,and at the same time makes the BSC perfect.展开更多
According to concrete age, the dynamic stress intensity factors of bond interface crack of concrete-rock was calculated. Result shows that the propagation of concreteinterface crack is mainly caused by tensile stress ...According to concrete age, the dynamic stress intensity factors of bond interface crack of concrete-rock was calculated. Result shows that the propagation of concreteinterface crack is mainly caused by tensile stress and shear stress for stress wave reflection. With the growth of concrete age, interface crack fracture toughness increases, and itscapacity of resisting blasting load strengthens. Therefore, blasting vibration should bestrictly controlled for fresh concrete.展开更多
Two time-domain reflectometry (TDR) systems and a new impedance measuring instrument, Thetaprobe,which are based on determination of soil dielectric constant, were used to measure water content of clayeyred soil to er...Two time-domain reflectometry (TDR) systems and a new impedance measuring instrument, Thetaprobe,which are based on determination of soil dielectric constant, were used to measure water content of clayeyred soil to eraluate the accuracy of these instruments. The results indicated that these instruments shouldbe carefUlly re-calibrated before being applied in clayey red soil. With a new calibration curve fed into one ofthe TDR systems tested, nase system, the measured data compared well with tho8e by standard oven-dryingmethod.展开更多
The wide application of pre-stressed bolting technology in coal mine tunnels has made the nondestructive stress wave reflection method of determining bolting quality an important one. The effect of the support plate o...The wide application of pre-stressed bolting technology in coal mine tunnels has made the nondestructive stress wave reflection method of determining bolting quality an important one. The effect of the support plate on the dynamic response of the pre-stressed anchor is of particular interest. A theoretical analysis and numerical simulations are used to identify the factors affecting the contact stress between the support plate and the rock wall. A formula allowing the calculation of contact stress is presented. Stress wave propagation through the nut, support plate, and rock wall are predicted. The dynamic response signals were measured in the field using prestressed anchors pre-tightened to different torques. The effects from the support plate on the dynamic response were recorded and the results compared to the predictions of pre-stressed anchor. This work provides a theoretical reference for the signal processing of dynamic reflected wave signals in anchor bolts.展开更多
The shapes and geometrical parameters of nozzles are key factors for fluidics. The relationship among the reaction thrust, flow rate pressure, diameter do and length L of a cylinder nozzle is analyzed theoretically. T...The shapes and geometrical parameters of nozzles are key factors for fluidics. The relationship among the reaction thrust, flow rate pressure, diameter do and length L of a cylinder nozzle is analyzed theoretically. The simulation of the flow field characteristics was conducted via the FLUENT computational fluid dynamics package. Effects of the inlet conditions and the nozzle dimensions on the reaction thrust of a water jet were addressed particularly. The reaction thrust experiments were performed on a custom-designed test apparatus. The experimental results reveal that a) the nozzle diameter and the inlet conditions exert great influence on the water jet reaction thrust; and b) for L≤4d0, where the nozzle is treated as a thin plate-orifice, the reaction thrust is independent of nozzle length; for L〉4d0, where the nozzle is treated as a long orifice, the reaction thrust can reach maximum under the condition of a certain flow rate. These findings lay a theoretical foundation for the design of nozzles and have significant value, especially for the future development of high-oressure water-let orooulsion technology.展开更多
Objective: The present study was designed to investigate the effect of microinfusion angiotensin Ⅱ(Ang Ⅱ),Ang Ⅱ type 1(AT_1)receptor antagonist losartan into the rostral ventrolateral medulla(RVLM)on the barorecept...Objective: The present study was designed to investigate the effect of microinfusion angiotensin Ⅱ(Ang Ⅱ),Ang Ⅱ type 1(AT_1)receptor antagonist losartan into the rostral ventrolateral medulla(RVLM)on the baroreceptor reflex sensitivity(BRS)in urethane-anesthetized rats. Methods: Reflex changes in heart rate(HR)were elicited by bolus intravenous injection of phenylephrine before and during RVLM microinfusion of saline(0.5 μl/h),Ang Ⅱ (1.5 nmol/h),losartan(250 nmol/h),and Ang Ⅱ(1.5 nmol/h)pretreated with microinjection of losartan (50 nmol/0.51 μl)into the RVLM.The average ratio between changes in HR in beats per minute(beats·min -1)and changes in mean arterial pressure [MAP,mmHg(1 mmHg=0.133 kPa)] was used as an index of BRS. Results: Ang Ⅱ resulted in a significant decrease in the BRS for reflex bradycardia compared with control(-2.1±0.1 vs-3.9±0.4 beats·min -1·mmHg -1).Microinfusion of losartan had no significant effect on BRS for reflex bradycardia.The effect of Ang Ⅱ was almost completely abolished by pretreatment with microinjection of losartan. Conclusion:These results showed that the exogenous Ang Ⅱ in the RVLM produces inhibitory modulation of BRS,which is mediated by AT_1 receptor.However,AT_1 receptor in the RVLM is not involved in the tonic control of BRS.展开更多
We studied the dynamic fracture mechanical behavior of rock under different impact rates. The fracture experiment was a three-point bending beam subjected to different impact loads monitored using the reflected causti...We studied the dynamic fracture mechanical behavior of rock under different impact rates. The fracture experiment was a three-point bending beam subjected to different impact loads monitored using the reflected caustics method. The mechanical parameters for fracture of the three-poim bending beam specimen under impact load are analyzed. The mechanism of crack propagation is discussed. Experimental results show that the dynamic stress intensity factor increases before crack initiation. When the dynamic stress intensity factor reaches its maximum value the crack starts to develop. After crack initiation the dynamic stress intensity factor decreases rapidly and oscillates. As the impact rate increases the cracks initiate earlier, the maximum value of crack growth velocity becomes smaller and the values of dynamic stress intensity factor also vary less during crack propagation. The results provide a theoretical basis for the study of rock dynamic fracture.展开更多
The hysteresis of saturation-capillary pressure (S-p) relations was investigated in a fine sandy medium under consecutive drainage-imbibition cycles, which resulted from scheduled water level fluctuations. A drainag...The hysteresis of saturation-capillary pressure (S-p) relations was investigated in a fine sandy medium under consecutive drainage-imbibition cycles, which resulted from scheduled water level fluctuations. A drainage-imbibition cycle starts with a drainage process and ends with an imbibition process in sequence. The saturation and capillary pressure were measured online with time domain reflectometry (TDR) probes and T5 tensiometers, respectively. Results show that the relation between the degree of hysteresis and the number of the drainage-imbibition cycles is not obvious. However, the degree decreases with the increase of the initial water saturation of the imbibition processes in these drainage-imbibition cycles. The air-entry pressure of a sandy medium is also found to be constant, which is independent of the drainage-imbibition cycles and the initial water saturation of the drainage process. In all the imbibition processes, parameter a of the van Genuchten (VG) model decreases with the increase of the initial water saturation, which corresponds positively to the magnitude of the hysteresis.展开更多
The electromagnetic emission(EME) induced from the rock containing piezoelectric materials was investigated under both static stress and exploding stress wave in the view of piezoelectric effect. The results show that...The electromagnetic emission(EME) induced from the rock containing piezoelectric materials was investigated under both static stress and exploding stress wave in the view of piezoelectric effect. The results show that the intensity of the EME induced from the rock under static stress increases with increasing stress level and loading rate; the relationship between the amplitude of the EME from the rock under different modes of stress wave and elastic parameters and propagation distance was presented. The intensity of the EME relates not only to the strength and elastic moduli of rock masses,but also to the initial damage of the rock. The intensity of EME induced by stress wave reaches the highest at the explosion-center and attenuates with the propagation distance. The intensity of EME increases with increasing the elastic modulus and decreases with increasing initial damage. The results are in good agreement with the experimental results.展开更多
We report a newly constructed laser ablation crossed molecular beam apparatus, equipped with time-sliced velocity map imaging technique, to study state-to-state metal atom reaction dynamics. Supersonic metal atomic be...We report a newly constructed laser ablation crossed molecular beam apparatus, equipped with time-sliced velocity map imaging technique, to study state-to-state metal atom reaction dynamics. Supersonic metal atomic beam is generated by laser vaporization of metal rod, and free expansion design without gas flow channel has been employed to obtain a good quality of metal atomic beam. We have chosen the crossed-beam reaction Al+O2 to test the performance of the new apparatus. Two-rotational-states selected AIO(X^2∑+, v=0, N and N+I4) products can be imaged via P(N) and R(N+14) branches of the Av=l band at the same wavelength, during (1+1) resonance-enhanced multi-photon ionization through the AIO(D2E+) intermediate state. In our experiment at 244.145 nm for simultaneous transitions of P(15) and R(29) branch, two rings in slice image were clearly distinguishable, corresponding to the AiO(v=0, N=IS) and AIO(v=0, N=29) states respectively. The energy difference between the two rotational levels is 403 cm^-1. The success of two states resolved in our apparatus suggests a better collisional energy resolution compared with the recent research study [J. Chem. Phys. 140, 214304 (2014)].展开更多
Fully A-doublet resolved differential cross sections and collision-induced rotational alignment moments have been measured for the NO(X)-Xe collision system at a collision energy of 519 cm^-1.The experiments combine i...Fully A-doublet resolved differential cross sections and collision-induced rotational alignment moments have been measured for the NO(X)-Xe collision system at a collision energy of 519 cm^-1.The experiments combine initial quantum state selection,employing a hexapole inhomogeneous electric field,with quantum state resolved detection,using(1+1')resonantly enhanced multiphoton ionization and velocity map ion imaging.The differential cross sections and polarization dependent differential cross sections are shown to agree well with quantum mechanical scattering calculations performed on ab initio potential energy surfaces[J.Klos et al.J.Chem.Phys.137,014312(2012)].By comparison with quasi-classical trajectory calculations,quantum mechanical scattering calculations on a hard-shell potential,and kinematic apse model calculations,the effects of the attractive part of the potential on the measured differential cross sections and collision-induced rotational alignment moments are assessed.展开更多
We describe the earlier unknown, when applied to global tectonics, centrifugal inertial mechanism of lithosphere plate moving under the effect of forces appearing as a result of Earth’s planetary rotation. The mechan...We describe the earlier unknown, when applied to global tectonics, centrifugal inertial mechanism of lithosphere plate moving under the effect of forces appearing as a result of Earth’s planetary rotation. The mechanism stated gives an insight into global tectonics of plates with the indirect participation of emanation streams which, in their turn, are the derivatives of centrifugal and inertial forces of planetary motion. The application of this mechanism provides a logical explanation for the regularities of global tectogenesis including the formation of mountain ridges mainly of submeridional and sublatitudinal strike, and also the drift of continental plates from the east to the west and from the south to the north. The mechanism clarifies the significance of the Arctic and the Antarctic Circles as geodynamic barriers.展开更多
To research techniques for removing the water blocking effect caused by hydraulic applications in coal seams,the use of surfactants is proposed,based on the mechanics of the water blocking effect.Centrifugal experimen...To research techniques for removing the water blocking effect caused by hydraulic applications in coal seams,the use of surfactants is proposed,based on the mechanics of the water blocking effect.Centrifugal experiments were used to validate the effects of using surfactants;the results show that after dealing with vacuum saturation with water,the volume of micropores decreases,which results in a larger average pore size,and the volume of transitional pores,mesopores,macropores and total pores increases.Based on the distribution of pore size,the operation mode of ‘‘water infusion after gas extraction,then continuing gas extraction" is recommended to improve the volume of coal mine gas drainage.When the reflectance of vitrinite in coal samples is less than 1,using the surfactants Fast T,1631,APG,BS can mitigate the damage caused by the water blocking effect.But when the reflectance of vitrinite is larger than 1.4,the damage caused by the water blocking effect can be increased.When the surfactant CMC is used in hydraulic applications,the capillary forces of coal samples are almost negative,which means the capillary force is in the same direction as the gas extraction.The direction of capillary forces benefits the gas flow.So,using CMC can play an active role in removing the water blocking effect.Centrifugal experiments confirm that using CMC can effectively remove the water blocking effect,which has a beneficial effect on improving the gas drainage volume.展开更多
基金The National Natural Science Foundation of China(No.51178114,51378122)
文摘In order to delay or eliminate the occurrence and expansion of the reflective cracking in the asphalt concrete overlay on old cement concrete pavement, an epoxy asphalt geogrid stress-absorbing layer( EAGSAL) was designed. The EAGSAL consists of epoxy asphalt and fiberglass geogrid. The pull-out test, skewshearing test, bending beam test and fatigue test were conducted to evaluate the performance of the EAGSAL and a traditional stress-absorbing layer( TSAL). The results showthat the adhesive performance, shear performance, bending strength and fatigue performance of the EAGSAL with an optimal spraying volume of epoxy asphalt are better than those of optimally designed TSAL, and the maximum bending strain of the EAGSAL is very close to that of the TSAL. The EAGSAL has superior performance in reflective cracking resistance.Moreover, the EAGSAL with the optimal spraying volume of approximately 2. 0 L m^2 is thinner and lighter than the TSAL,which can decrease the thickness and improve the bearing ability of the whole pavement structure.
基金This work was supported by the Chinese Academy of Sciences, the Ministry of Science and Technology and the National Natural Science Foundation of China.ACKN0WLEDGMENT This work was supported by the Chinese Academy of Sciences, the Ministry of Science and Technology and the National Natural Science Foundation of China.
文摘A crossed molecular beams, state-to-state scattering study was carried out on the F+H2→HF+H reaction at the collision energy of 5.02 kJ/mol, using the highly sensitive H atom Rydberg tagging time-of-flight method. All the peaks in the TOF spectra can be clearly assigned to the ro-vibrational structures of the HF product. The forward scattering of the HF product at v′=3 has been observed. The small forward scattering of the HF product at v′=2 has also been detected. Detailed theoretical analysis is required in order to fully understand the dynamical origin of these forward scattering products at this high collision energy.
基金Sponsored by the Key Science Research Project of Abroad Scholars of Heilongjiang Province(Grant No.1055HZ029).
文摘Taking into consideration the disadvantage of Balanced Scorecard(BSC)not being able to reflect time delay,nonlinear problems of causal relationship and being lack of effective simulation,we combined it with the characteristics of the System Dynamics(SD).Basing on the background of manufacturing enterprises,through SD integrating with the BSC we established a new performance evaluation method-SD-BSC method to overcome the disadvantage of BSC.A performance evaluation model of SD-BSC is provided and the simulation results are analyzed which show different production policies will lead to different customer's satisfaction degrees.The SD-BSC dynamic performance evaluation method can reflect dynamic,complex causal feedback relationship and time delay,so it compensates for the disadvantage of traditional financial performance evaluation method,and at the same time makes the BSC perfect.
基金Supported by the National Natural Science Foundation of China(50774056,50779050)Scientific Research Fund of Wuhan University of Science and Technology(080068,2008XY19)
文摘According to concrete age, the dynamic stress intensity factors of bond interface crack of concrete-rock was calculated. Result shows that the propagation of concreteinterface crack is mainly caused by tensile stress and shear stress for stress wave reflection. With the growth of concrete age, interface crack fracture toughness increases, and itscapacity of resisting blasting load strengthens. Therefore, blasting vibration should bestrictly controlled for fresh concrete.
文摘Two time-domain reflectometry (TDR) systems and a new impedance measuring instrument, Thetaprobe,which are based on determination of soil dielectric constant, were used to measure water content of clayeyred soil to eraluate the accuracy of these instruments. The results indicated that these instruments shouldbe carefUlly re-calibrated before being applied in clayey red soil. With a new calibration curve fed into one ofthe TDR systems tested, nase system, the measured data compared well with tho8e by standard oven-dryingmethod.
基金Financial support for this work, provided by the National Natural Science Foundation of China (No.50874104)
文摘The wide application of pre-stressed bolting technology in coal mine tunnels has made the nondestructive stress wave reflection method of determining bolting quality an important one. The effect of the support plate on the dynamic response of the pre-stressed anchor is of particular interest. A theoretical analysis and numerical simulations are used to identify the factors affecting the contact stress between the support plate and the rock wall. A formula allowing the calculation of contact stress is presented. Stress wave propagation through the nut, support plate, and rock wall are predicted. The dynamic response signals were measured in the field using prestressed anchors pre-tightened to different torques. The effects from the support plate on the dynamic response were recorded and the results compared to the predictions of pre-stressed anchor. This work provides a theoretical reference for the signal processing of dynamic reflected wave signals in anchor bolts.
基金Funded by the Natural Science Foundation of China (No. 50775081)the National High-tech R&D (863) Program No. 2006AA09Z238)the NCET-07-0330, State Education Ministry.
文摘The shapes and geometrical parameters of nozzles are key factors for fluidics. The relationship among the reaction thrust, flow rate pressure, diameter do and length L of a cylinder nozzle is analyzed theoretically. The simulation of the flow field characteristics was conducted via the FLUENT computational fluid dynamics package. Effects of the inlet conditions and the nozzle dimensions on the reaction thrust of a water jet were addressed particularly. The reaction thrust experiments were performed on a custom-designed test apparatus. The experimental results reveal that a) the nozzle diameter and the inlet conditions exert great influence on the water jet reaction thrust; and b) for L≤4d0, where the nozzle is treated as a thin plate-orifice, the reaction thrust is independent of nozzle length; for L〉4d0, where the nozzle is treated as a long orifice, the reaction thrust can reach maximum under the condition of a certain flow rate. These findings lay a theoretical foundation for the design of nozzles and have significant value, especially for the future development of high-oressure water-let orooulsion technology.
文摘Objective: The present study was designed to investigate the effect of microinfusion angiotensin Ⅱ(Ang Ⅱ),Ang Ⅱ type 1(AT_1)receptor antagonist losartan into the rostral ventrolateral medulla(RVLM)on the baroreceptor reflex sensitivity(BRS)in urethane-anesthetized rats. Methods: Reflex changes in heart rate(HR)were elicited by bolus intravenous injection of phenylephrine before and during RVLM microinfusion of saline(0.5 μl/h),Ang Ⅱ (1.5 nmol/h),losartan(250 nmol/h),and Ang Ⅱ(1.5 nmol/h)pretreated with microinjection of losartan (50 nmol/0.51 μl)into the RVLM.The average ratio between changes in HR in beats per minute(beats·min -1)and changes in mean arterial pressure [MAP,mmHg(1 mmHg=0.133 kPa)] was used as an index of BRS. Results: Ang Ⅱ resulted in a significant decrease in the BRS for reflex bradycardia compared with control(-2.1±0.1 vs-3.9±0.4 beats·min -1·mmHg -1).Microinfusion of losartan had no significant effect on BRS for reflex bradycardia.The effect of Ang Ⅱ was almost completely abolished by pretreatment with microinjection of losartan. Conclusion:These results showed that the exogenous Ang Ⅱ in the RVLM produces inhibitory modulation of BRS,which is mediated by AT_1 receptor.However,AT_1 receptor in the RVLM is not involved in the tonic control of BRS.
基金the support of the National Natural Science Foundation of China (Grant No.50774086 and 50874109)
文摘We studied the dynamic fracture mechanical behavior of rock under different impact rates. The fracture experiment was a three-point bending beam subjected to different impact loads monitored using the reflected caustics method. The mechanical parameters for fracture of the three-poim bending beam specimen under impact load are analyzed. The mechanism of crack propagation is discussed. Experimental results show that the dynamic stress intensity factor increases before crack initiation. When the dynamic stress intensity factor reaches its maximum value the crack starts to develop. After crack initiation the dynamic stress intensity factor decreases rapidly and oscillates. As the impact rate increases the cracks initiate earlier, the maximum value of crack growth velocity becomes smaller and the values of dynamic stress intensity factor also vary less during crack propagation. The results provide a theoretical basis for the study of rock dynamic fracture.
基金Project(41072182) supported by the National Natural Science Foundation of ChinaProject(2010Z1-E101) supported by the Science and Technology Program of Guangzhou City,China+1 种基金Project(200809095) supported by the Special Funds for Environmental Nonprofit Research,ChinaProject(8151027501000008) supported by the Natural Science Foundation of Guangdong Province,China
文摘The hysteresis of saturation-capillary pressure (S-p) relations was investigated in a fine sandy medium under consecutive drainage-imbibition cycles, which resulted from scheduled water level fluctuations. A drainage-imbibition cycle starts with a drainage process and ends with an imbibition process in sequence. The saturation and capillary pressure were measured online with time domain reflectometry (TDR) probes and T5 tensiometers, respectively. Results show that the relation between the degree of hysteresis and the number of the drainage-imbibition cycles is not obvious. However, the degree decreases with the increase of the initial water saturation of the imbibition processes in these drainage-imbibition cycles. The air-entry pressure of a sandy medium is also found to be constant, which is independent of the drainage-imbibition cycles and the initial water saturation of the drainage process. In all the imbibition processes, parameter a of the van Genuchten (VG) model decreases with the increase of the initial water saturation, which corresponds positively to the magnitude of the hysteresis.
基金Project(50490274) supported by National Natural Science Foundation of China
文摘The electromagnetic emission(EME) induced from the rock containing piezoelectric materials was investigated under both static stress and exploding stress wave in the view of piezoelectric effect. The results show that the intensity of the EME induced from the rock under static stress increases with increasing stress level and loading rate; the relationship between the amplitude of the EME from the rock under different modes of stress wave and elastic parameters and propagation distance was presented. The intensity of the EME relates not only to the strength and elastic moduli of rock masses,but also to the initial damage of the rock. The intensity of EME induced by stress wave reaches the highest at the explosion-center and attenuates with the propagation distance. The intensity of EME increases with increasing the elastic modulus and decreases with increasing initial damage. The results are in good agreement with the experimental results.
基金We are indebted to Prof. Kopin Liu (IAMS, Taipei) for stimulating discussions on going experiments, to Prof. Ming-fei Zhou and Assoc. Prof. Guan-jun Wang (Fudan University, Shanghai) for assistance in building machine, to Prof. Uzi. Even (Tel Aviv University, Tel Aviv) for discussions oil E1 valve employnmnt in laser ablation, and to Prof. Xue-ming Yang's group (DICP, Dalian) for new Iaser system. This work was supported by the National Natural Science Foundation of China (No.21322309) and the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning.
文摘We report a newly constructed laser ablation crossed molecular beam apparatus, equipped with time-sliced velocity map imaging technique, to study state-to-state metal atom reaction dynamics. Supersonic metal atomic beam is generated by laser vaporization of metal rod, and free expansion design without gas flow channel has been employed to obtain a good quality of metal atomic beam. We have chosen the crossed-beam reaction Al+O2 to test the performance of the new apparatus. Two-rotational-states selected AIO(X^2∑+, v=0, N and N+I4) products can be imaged via P(N) and R(N+14) branches of the Av=l band at the same wavelength, during (1+1) resonance-enhanced multi-photon ionization through the AIO(D2E+) intermediate state. In our experiment at 244.145 nm for simultaneous transitions of P(15) and R(29) branch, two rings in slice image were clearly distinguishable, corresponding to the AiO(v=0, N=IS) and AIO(v=0, N=29) states respectively. The energy difference between the two rotational levels is 403 cm^-1. The success of two states resolved in our apparatus suggests a better collisional energy resolution compared with the recent research study [J. Chem. Phys. 140, 214304 (2014)].
基金The support of the UK EPSRC to Mark Brouard via Programme Grant EP/L005913/1the Spanish Ministry of Science and Innovation(Grant PGC2018-096444-B-I00 MINECO/FEDER)to F.Javier Aoiz are gratefully acknowledged+2 种基金funding by Fundación Salamanca City of Culture and Knowledge(Programme for attracting Scientific Talent to Salamanca)support through U.S.National Science Foundation under Grant No.CHE-1565872 to Millard H.Alexander.
文摘Fully A-doublet resolved differential cross sections and collision-induced rotational alignment moments have been measured for the NO(X)-Xe collision system at a collision energy of 519 cm^-1.The experiments combine initial quantum state selection,employing a hexapole inhomogeneous electric field,with quantum state resolved detection,using(1+1')resonantly enhanced multiphoton ionization and velocity map ion imaging.The differential cross sections and polarization dependent differential cross sections are shown to agree well with quantum mechanical scattering calculations performed on ab initio potential energy surfaces[J.Klos et al.J.Chem.Phys.137,014312(2012)].By comparison with quasi-classical trajectory calculations,quantum mechanical scattering calculations on a hard-shell potential,and kinematic apse model calculations,the effects of the attractive part of the potential on the measured differential cross sections and collision-induced rotational alignment moments are assessed.
文摘We describe the earlier unknown, when applied to global tectonics, centrifugal inertial mechanism of lithosphere plate moving under the effect of forces appearing as a result of Earth’s planetary rotation. The mechanism stated gives an insight into global tectonics of plates with the indirect participation of emanation streams which, in their turn, are the derivatives of centrifugal and inertial forces of planetary motion. The application of this mechanism provides a logical explanation for the regularities of global tectogenesis including the formation of mountain ridges mainly of submeridional and sublatitudinal strike, and also the drift of continental plates from the east to the west and from the south to the north. The mechanism clarifies the significance of the Arctic and the Antarctic Circles as geodynamic barriers.
基金financially supported by the National Natural Science Foundation of China (No.51504084)the Education Department of Fujian Province (No.JA15493)
文摘To research techniques for removing the water blocking effect caused by hydraulic applications in coal seams,the use of surfactants is proposed,based on the mechanics of the water blocking effect.Centrifugal experiments were used to validate the effects of using surfactants;the results show that after dealing with vacuum saturation with water,the volume of micropores decreases,which results in a larger average pore size,and the volume of transitional pores,mesopores,macropores and total pores increases.Based on the distribution of pore size,the operation mode of ‘‘water infusion after gas extraction,then continuing gas extraction" is recommended to improve the volume of coal mine gas drainage.When the reflectance of vitrinite in coal samples is less than 1,using the surfactants Fast T,1631,APG,BS can mitigate the damage caused by the water blocking effect.But when the reflectance of vitrinite is larger than 1.4,the damage caused by the water blocking effect can be increased.When the surfactant CMC is used in hydraulic applications,the capillary forces of coal samples are almost negative,which means the capillary force is in the same direction as the gas extraction.The direction of capillary forces benefits the gas flow.So,using CMC can play an active role in removing the water blocking effect.Centrifugal experiments confirm that using CMC can effectively remove the water blocking effect,which has a beneficial effect on improving the gas drainage volume.