In this study, the three-dimensional non-premixed two-phase kerosene/air rotating detonation engines with different isolator configurations and throat area ratios are simulated by the Eulerian-Lagrangian method. The e...In this study, the three-dimensional non-premixed two-phase kerosene/air rotating detonation engines with different isolator configurations and throat area ratios are simulated by the Eulerian-Lagrangian method. The effects of the divergence, straight, and convergence isolators on the rotating detonation wave dynamics and the upstream oblique shock wave propagation mechanism are analyzed. The differences in the rotating detonation wave behaviors between ground and flight operations are clarified.The results indicate that the propagation regimes of the upstream oblique shock wave depend on the isolator configurations and operation conditions. With a divergence isolator, the airflow is accelerated throughout the isolator and divergence section, leading to a maximum Mach number(~1.8) before the normal shock. The total pressure loss reaches the largest, and the detonation pressure drops. The upstream oblique shock wave can be suppressed within the divergence section with the divergence isolator.However, for the straight and convergence isolators, the airflow in the isolator with a larger ψ_(1)(0.3 and0.4) can suffer from the disturbance of the upstream oblique shock wave. The critical incident angle is around 39° at ground operation conditions. The upstream oblique shock wave tends to be suppressed when the engine operates under flight operation conditions. The critical pressure ratio β_(cr0) is found to be able to help in distinguishing the propagation regimes of the upstream oblique shock wave. Slightly below or above the β_(cr0) can obtain different marginal propagation results. The high-speed airflow in the divergence section affects the fuel droplet penetration distance, which deteriorates the reactant mixing and the detonation area. Significant detonation velocity deficits are observed and the maximum velocity deficit reaches 26%. The results indicate the engine channel design should adopt different isolator configurations based on the purpose of total pressure loss or disturbance suppression. This study can provide useful guidance for the channel design of a more complete two-phase rotating detonation engine.展开更多
Vibration isolation is an effective method to mitigate unwanted disturbances arising from dynamic loading conditions. With smart materials as suitable substitutes, the conventional passive isolators have attained attr...Vibration isolation is an effective method to mitigate unwanted disturbances arising from dynamic loading conditions. With smart materials as suitable substitutes, the conventional passive isolators have attained attributes of semi-active as well as the active control system. In the present study, the non-homogenous field-dependent isolation capabilities of the magnetorheological elastomer are explored under torsional vibrations. Torsional natural frequency was measured using the serial arrangement of accelerometers. Novel methods are introduced to evaluate the torsional stiffness variations of the isolator for a semi-definite and a motor-coupled rotor system. For the semi-definite system, the isolation effect was studied using the frequency response functions from the modal analysis. The speed-dependent variations for motor-coupled rotor system were assessed using the shift in frequency amplitudes from torque transducers. Finite element method magnetics was used to study the variations in the non-homogenous magnetic field across the elastomer. The response functions for the semi-definite rotor system reveal a shift in the frequency in the effect of the magnetic field. Speed-dependent variations in the frequency domain indicate an increment of 9% in the resonant frequency of the system.展开更多
The differential cubature solution to the problem of a Mindlin plate lying on the Winkler foundation with two simply supported edges and two clamped edges was derived.Discrete numerical technology and shape functions ...The differential cubature solution to the problem of a Mindlin plate lying on the Winkler foundation with two simply supported edges and two clamped edges was derived.Discrete numerical technology and shape functions were used to ensure that the solution is suitable to irregular shaped plates.Then,the mechanical model and the solution were employed to model the protection layer that isolates the mining stopes from sea water in Sanshandao gold mine,which is the first subsea mine of China.Furthermore,thickness optimizations for the protection layers above each stope were conducted based on the maximum principle stress criterion,and the linear relations between the best protection layer thickness and the stope area under different safety factors were regressed to guide the isolation design.The method presented in this work provides a practical way to quickly design the isolation layer thickness in subsea mining.展开更多
According to physiological and biochemical characteristics of Leptospirillum ferriphilum, a strain of object bacteria was isolated successfully. Bacteria were enriched by selective liquid medium and plated on designed...According to physiological and biochemical characteristics of Leptospirillum ferriphilum, a strain of object bacteria was isolated successfully. Bacteria were enriched by selective liquid medium and plated on designed single-layered agar solid medium. Colony was cultured and bacteria were collected. The morphologies of the object bacteria were observed using crystal violet staining, scanning electron microscope（SEM） and transmission electron microscope （TEM）. The result of 16S rDNA identification shows that this bacterium belongs to Leptospirillum ferriphilum and it is named as Leptospirillum ferriphilum strain D1. These results indicate that this new single-layered agar solid medium is efficient and physiological-biochemical characteristics show that the optimum simple for isolation of Leptospirillum ferriphilum. Additionally, initial pH value and its growth temperature are 1.68 and 40℃.展开更多
The micromation and precision of the Micro-Electromechanical System demand that its manufacturing, measuring and assembling must work in a micro-manufacturing platform with good ability to isolate vibrations. This pap...The micromation and precision of the Micro-Electromechanical System demand that its manufacturing, measuring and assembling must work in a micro-manufacturing platform with good ability to isolate vibrations. This paper develops a vibration isolation system of micro-manufacturing platform. The brains of many kinds of birds can isolate vibrations well, such as woodpecker’s brain. When a woodpecker pecks the wood at the speed as 1.6 times as the velocity of sound, its brain will tolerate the wallop 1 500 times of the weight of itself without any damage. The isolation mechanics and organic texture of woodpecker’s brain that has good isolation characteristics were studied. A structure model of vibration isolation system for the micro-manufacturing platform is established based on the bionics of the bird’s brain vibration isolation mechanism. In order to isolate effectively the high frequency vibrations from the ground, a rubber layer is used to isolate vibrations passively between the micro-manufacturing platform’s pedestal and the ground. This layer corresponds to the cartilage and muscles in the outer meninges of the bird’s brain. The active vibration isolation technique is adopted to isolate vibrations between the micro-manufacturing platform and the pedestal. Air springs are used as elastic components, which correspond to the interspaces between the outer meninges and the encephala of the bird’s brain. Actuators are made of giant magnetostrictive material, and it corresponds to the nerves and neural muscles linking the meninges and the encephala. The actuators and air springs are arranged vertically in parallel to make use of the giant magnetostrictive actuators effectively. The air springs support almost all weight of the micro-manufacturing platform and the giant magnetostrictive actuators support almost no weight. In order to realize high performance to isolate complex micro-vibration, the control method using a three-layer neural network is presented. This vibration control system takes into account the floor disturbance and the direct disturbance acting on the micro-manufacturing platform. The absolute acceleration of the micro-manufacturing platform is used as the performance index of vibration control. The performance of the control system is tested by numerical simulation. Simulation results show that the active vibration isolation system has good isolation performance against the floor disturbance and the direct disturbance acting on the micro-manufacturing platform in all the frequency range.展开更多
Lonicera caerulea L.fruit is an excellent source of bioactive compounds.An efficient separation method of cyanins is important for the development of many value-added products and functional food ingredients.High-spee...Lonicera caerulea L.fruit is an excellent source of bioactive compounds.An efficient separation method of cyanins is important for the development of many value-added products and functional food ingredients.High-speed counter-current chromatography(HSCCC) was applied to isolate cyanins from Lonicera caerulea fruits with a biphasic solvent system composed of methyl tert-butyl ether/n-butanol/acetonitrile/water/trifluoroacetic acid(2:2:1:5:0.01,volume ratio).1.41 mg of cyanidin 3,5-O-diglucoside,1.08 mg of cyanidin 3-O-rutinoside and 6.38 mg of cyanidin 3-O-glucoside were obtained from 40 mg of crude extract.The purities of these compounds were 95.8%,92.4% and 97.6%,respectively,as identified by high-performance liquid chromatography–diode array detection(HPLC-DAD) and high-performance liquid chromatography-electrospray ionization mass spectrometryn(HPLC-ESI/MSn).In addition,the dominant anthocyanin,cyanidin 3-O-glucoside was demonstrated cytotoxic response of human hepatocarcinoma SMMC-7721 cells,inducing live cancer cell apoptotic by flow cytometric analysis.展开更多
The complex systems are often in the structure of multi-operating modes, and the components implementing system functions are different under different operation modes, which results in the problems that components of...The complex systems are often in the structure of multi-operating modes, and the components implementing system functions are different under different operation modes, which results in the problems that components often fail in different operating modes, faults can be only detected in specified operating modes, tests can be available in specified operating modes,and the cost and efficiency of detecting and isolating faults are different under different operating modes and isolation levels. Aiming at these problems, an optimal test selection method for fault detection and isolation in the multi-operating mode system is proposed by using the fault pair coding and rollout algorithm. Firstly,the faults in fault-test correlation matrices under different operating modes are combined to fault-pairs, which is used to construct the fault pair-test correlation matrices under different operating modes.Secondly, the final fault pair-test correlation matrix of the multioperating mode system is obtained by operating the fault pair-test correlation matrices under different operating modes. Based on the final fault pair-test correlation matrix, the necessary tests are selected by the rollout algorithm orderly. Finally, the effectiveness of the proposed method is verified by examples of the optimal test selection in the multi-operating mode system with faults isolated to different levels. The result shows that the proposed method can effectively mine the fault detection and isolation ability of tests and it is suitable for the optimal test selection of the multi-operating mode system with faults isolated to the replacement unit and specific fault.展开更多
An application of the multiobjective fault detection and isolation（FDI） approach to an air-breathing hypersonic vehicle（HSV） longitudinal dynamics subject to disturbances is presented.Maintaining sustainable and s...An application of the multiobjective fault detection and isolation（FDI） approach to an air-breathing hypersonic vehicle（HSV） longitudinal dynamics subject to disturbances is presented.Maintaining sustainable and safe flight of HSV is a challenging task due to its strong coupling effects,variable operating conditions and possible failures of system components.A common type of system faults for aircraft including HSV is the loss of effectiveness of its actuators and sensors.To detect and isolate multiple actuator/sensor failures,a faulty linear parameter-varying（LPV） model of HSV is derived by converting actuator/system component faults into equivalent sensor faults.Then a bank of LPV FDI observers is designed to track individual fault with minimum error and suppress the effects of disturbances and other fault signals.The simulation results based on the nonlinear flexible HSV model and a nominal LPV controller demonstrate the effectiveness of the fault estimation technique for HSV.展开更多
A heterotrophic acidothermophilic bacterial strain,YNTC-1,was isolated from an acidic hot spring in Tengchong,Yunan,China.YNTC-1 grows at pH value of 1.5-8.0 and temperature of 40-70℃,with optimal pH and temperature ...A heterotrophic acidothermophilic bacterial strain,YNTC-1,was isolated from an acidic hot spring in Tengchong,Yunan,China.YNTC-1 grows at pH value of 1.5-8.0 and temperature of 40-70℃,with optimal pH and temperature at 3.0 and 55℃,respectively.The cells of the strain are in shape of short rod,with 1.0-1.2μm in length and 0.7-0.8μm in diameter,and with distinct spores at both poles of each cell.The predominant fatty acids in cellular membrane of the strain are C18:1ω7c.16s rRNA gene analysis reveals that this strain is closely related to Alicyclobacillus sendaiensis,with over 99%sequence similarity.Based on phenotypic and genotypic analyses,YNTC-1 is identified as a member of A.sendaiensis.Considering some important morphological and biochemical differences between strain YNTC-1 and A.sendaiensis ATCC 27009T,YNTC-1 may be proposed to be a novel subspecies of A.sendaiensis.However,this viewpoint has to be confirmed by further studies.Co-bioleaching of pyrite and chalcopyrite with strain YN22,Sulfobacillus thermosulfidooxidans,shows that strain YNTC-1 has no evident influence on bioleaching rates of these two sulphide minerals.展开更多
The lifetime of metal rubber isolator and its characteristics during lifetime experiment were studied. The stepped-up test principle was adopted to study the lifetime of resonant frequency, the breakage form of metal ...The lifetime of metal rubber isolator and its characteristics during lifetime experiment were studied. The stepped-up test principle was adopted to study the lifetime of resonant frequency, the breakage form of metal rubber isolator was obtained, and the relation between the energy dissipation, resonant frequency and stiffness was obtained in (available) lifetime of the isolator. Furthermore, the reason for the changes of properties of metal rubber isolator was analyzed with contact model of metal rubber material. The results show that if the resonant amplitude is large, the stiffness of metal rubber isolator will be kept steadily for a long time, its resonant frequency will be stable and the effective working time in the protecting area will be long. The lifetime of metal rubber isolator is more than 1376 h in the experiment. The main failure forms of metal rubber isolator are accumulative wear and breaking of metal wires and spirals. In protecting area the metal rubber isolator can work effectively for a long time, and the effective working time depends on the concrete working condition.展开更多
The development and application of spermatogonial stem cell technology have an important significance in animal cloning, preservation of endangered species and spermatogenesis research. In this study, the seminiferous...The development and application of spermatogonial stem cell technology have an important significance in animal cloning, preservation of endangered species and spermatogenesis research. In this study, the seminiferous epithlium cells were isolated and purified, the ceils were cryopreserved after identification, and the effects of different purification and cyopreservation methods on bovine testicular cells were studied. The results showed that there were spermatogonial stem cells and sertoli cells in the neonatal bovine seminiferous tubules, differential adherent selection methods could effectively separate these two cell types. Spermatogonial stem cells were positive after AKP, C-kit, and OCT-4 identification; sertoli ceils were positive after oil red O and vimentin identification. Frozen stock solution supplemented with 10% DMSO had the best effect in spermatogonial stem cell cryopreservation, while fxozen stock solution supplemented with 10% of ethylene glycol and 0.1 mmol. L^-1 trehalose had the best effect in sertoli cells crvooreservation.展开更多
The displacement feedback with time delay considered is introduced in order to enhance the vibration isolation performance of a high-static-low-dynamic stiffness(HSLDS) vibration isolator. Such feedback is detailedly ...The displacement feedback with time delay considered is introduced in order to enhance the vibration isolation performance of a high-static-low-dynamic stiffness(HSLDS) vibration isolator. Such feedback is detailedly analyzed from the viewpoint of equivalent damping. Firstly, the primary resonance of the controlled HSLDS vibration isolator subjected to a harmonic force excitation is obtained based on the multiple scales method and further verified by numerical integration. The stability of the primary resonance is subsequently investigated. Then, the equivalent damping is defined to study the effects of feedback gain and time delay on primary resonance. The condition of jump avoidance is obtained with the purpose of eliminating the adverse effects induced by jumps. Finally, the force transmissibility of the controlled HSLDS vibration isolator is defined to evaluate its isolation performance. It is shown that an appropriate choice of feedback parameters can effectively suppress the force transmissibility in resonant region and reduce the resonance frequency. Furthermore, a wider vibration isolation frequency bandwidth can be achieved compared to the passive HSLDS vibration isolator.展开更多
Effects of five incubation temperatures (25℃ ,28℃ ,31℃ ,35℃ and 37℃ for 24hours) and four incubation time periods (0.4,16 and 24 hours at 35℃) on isolated microspore culture of Chinese cabbage were studied. The ...Effects of five incubation temperatures (25℃ ,28℃ ,31℃ ,35℃ and 37℃ for 24hours) and four incubation time periods (0.4,16 and 24 hours at 35℃) on isolated microspore culture of Chinese cabbage were studied. The results showed that cultured microspores of Chinese cabbage developed into embryos at all the incubation temperatues from 28℃ to 37℃ ,but the best response to high temperature occured at 35℃. Among the four kinds of time periods, the highest yield of embryos was obtained at the 24h treatment. Therefore, the isolated microspore culture of Chinese cabbege ran be efficiently carried out at 35℃ for 24 hours.展开更多
The bottleneck of strontium compounds preparing from celestite is the promotion of Sr/S isolation efficiency.Low energy consumption and zero release method for isolating Sr/S in preparing Sr(OH)2 process from celestit...The bottleneck of strontium compounds preparing from celestite is the promotion of Sr/S isolation efficiency.Low energy consumption and zero release method for isolating Sr/S in preparing Sr(OH)2 process from celestite in mild condition was described.Sr element remained in precipitation with formation of Sr(OH)2,while S element entered into leachate with formation of Na2SO4.The effects of initial concentration of NaOH,conversion temperature,liquid-to-solid(L/S)ratio and conversion time on Sr/S ratio of samples for celestite conversion were systematically investigated by experiments.The results demonstrated that the efficiency of Sr/S isolation increased with the initial concentration of NaOH,L/S ratio and conversion time,and decreased with conversion temperature.The maximum conversion ratio of Sr(OH)2 was 93.88%under the optimum condition,whose Sr/S ratio of sample could reach to 41.16.It illustrated that better isolation efficiency of celestite could be achieved in alkaline treatment.The results of SEM-EDS analyses demonstrated that the conversion reaction was a dissolution-precipitation process.展开更多
A model to describe the hysteresis damping characteristic of rubber material was presented.It consists of a parallel spring and damper,whose coefficients change with the vibration amplitude and frequency.In order to a...A model to describe the hysteresis damping characteristic of rubber material was presented.It consists of a parallel spring and damper,whose coefficients change with the vibration amplitude and frequency.In order to acquire these relations,force decomposition was carried out according to some sine vibration measurement data of nonlinear forces changing with the deformation of the rubber material.The nonlinear force is decomposed into a spring force and a damper force,which are represented by the amplitude-and frequency-dependent spring and damper coefficients,respectively.Repeating this step for different measurements gives different coefficients corresponding to different amplitudes and frequencies.Then,the application of a parameter identification method provides the requested approximation functions over amplitude and frequency.Using those formulae,as an example,the dynamic characteristic of a hollow shaft system supported by rubber rings was analyzed and the acceleration response curve in the centroid position was calculated.Comparisons with the sine vibration experiments of the real system show a maximal inaccuracy of 8.5%.Application of this model and procedure can simplify the modeling and analysis of mechanical systems including rubber materials.展开更多
By taking a rolling-spring isolation system as the study object, the effects of the non-uniform distribution of rolling friction coefficient on its isolation performance were analyzed by a compiled computer program. T...By taking a rolling-spring isolation system as the study object, the effects of the non-uniform distribution of rolling friction coefficient on its isolation performance were analyzed by a compiled computer program. The results show that the errors associated with the structural maximum relative displacement, acceleration and residual displacement due to ignoring the friction variability sequentially grow. This rule is weakened by the spring action, however, the unreasonable spring constant will cause sympathetic vibration. Under the condition of large friction variability, in the calculation of the structural maximum relative displacement and acceleration, the friction variability should be considered. When the structural residual displacement is concerned, the variability of rolling friction coefficient should be fully considered regardless of the friction variability.展开更多
A facultative heterotrophic strain （DS-0205） was isolated from a deep-sea sediment sample collected at a depth of 5.2 km in the eastern Pacific Ocean, China. Strain DS-0205 is motile helmet-like single cell or pairs...A facultative heterotrophic strain （DS-0205） was isolated from a deep-sea sediment sample collected at a depth of 5.2 km in the eastern Pacific Ocean, China. Strain DS-0205 is motile helmet-like single cell or pairs, forming hemisphere with the center sunken of variable size. It has a widespread carbon source and nitrogen source, including agarose, citric acid, salicin, D-glucitol nitrate, sodium nitrite and cthylamine, tt can grow in the following environment： temperature 4-37℃, pH 2.0-12.0, tolerance to NaCl≤15%. Two phylogenetic trees, one based on the ITS and 5.8S rRNA sequences and the other based on the 18S rRNA sequences, unite strain DS-0205（=JCM 0205） to the type strain of Rhodosporidium diobovatum JCM 3787 through a considerable evolutionary distance. These results suggest that strain DS-0205 is a new strain of the Rhodosporidium diobovatum.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 12202204)the Natural Science Foundation of Jiangsu Province (Grant No. BK20220953)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Science and Technology Association's Young Talent Nurturing Program of Jiangsu Province (Grant No. JSTJ-2024-004)
文摘In this study, the three-dimensional non-premixed two-phase kerosene/air rotating detonation engines with different isolator configurations and throat area ratios are simulated by the Eulerian-Lagrangian method. The effects of the divergence, straight, and convergence isolators on the rotating detonation wave dynamics and the upstream oblique shock wave propagation mechanism are analyzed. The differences in the rotating detonation wave behaviors between ground and flight operations are clarified.The results indicate that the propagation regimes of the upstream oblique shock wave depend on the isolator configurations and operation conditions. With a divergence isolator, the airflow is accelerated throughout the isolator and divergence section, leading to a maximum Mach number(~1.8) before the normal shock. The total pressure loss reaches the largest, and the detonation pressure drops. The upstream oblique shock wave can be suppressed within the divergence section with the divergence isolator.However, for the straight and convergence isolators, the airflow in the isolator with a larger ψ_(1)(0.3 and0.4) can suffer from the disturbance of the upstream oblique shock wave. The critical incident angle is around 39° at ground operation conditions. The upstream oblique shock wave tends to be suppressed when the engine operates under flight operation conditions. The critical pressure ratio β_(cr0) is found to be able to help in distinguishing the propagation regimes of the upstream oblique shock wave. Slightly below or above the β_(cr0) can obtain different marginal propagation results. The high-speed airflow in the divergence section affects the fuel droplet penetration distance, which deteriorates the reactant mixing and the detonation area. Significant detonation velocity deficits are observed and the maximum velocity deficit reaches 26%. The results indicate the engine channel design should adopt different isolator configurations based on the purpose of total pressure loss or disturbance suppression. This study can provide useful guidance for the channel design of a more complete two-phase rotating detonation engine.
基金the support from SOLVE: The Virtual Lab @ NITK (Grant number: No.F.16-35/2009-DL, Ministry of Human Resources Development)
文摘Vibration isolation is an effective method to mitigate unwanted disturbances arising from dynamic loading conditions. With smart materials as suitable substitutes, the conventional passive isolators have attained attributes of semi-active as well as the active control system. In the present study, the non-homogenous field-dependent isolation capabilities of the magnetorheological elastomer are explored under torsional vibrations. Torsional natural frequency was measured using the serial arrangement of accelerometers. Novel methods are introduced to evaluate the torsional stiffness variations of the isolator for a semi-definite and a motor-coupled rotor system. For the semi-definite system, the isolation effect was studied using the frequency response functions from the modal analysis. The speed-dependent variations for motor-coupled rotor system were assessed using the shift in frequency amplitudes from torque transducers. Finite element method magnetics was used to study the variations in the non-homogenous magnetic field across the elastomer. The response functions for the semi-definite rotor system reveal a shift in the frequency in the effect of the magnetic field. Speed-dependent variations in the frequency domain indicate an increment of 9% in the resonant frequency of the system.
基金Projects(51504044,51204100)supported by National Natural Science Foundation of ChinaProject(14KF05)supported by the Research Fund of The State Key Laboratory of Coal Resources and Mine Safety,CUMT,China+3 种基金Project(cstc2016jcyj A1861)supported by the Research Fund of Chongqing Basic Science and Cutting-Edge Technology Special Projects,ChinaProject(2015CDJXY)supported by the Fundamental Research Funds for the Central UniversitiesProject supported by the China Postdoctoral Science FoundationProject(2011DA105287-MS201503)supported by the Independent Subject of State Key Laboratory of Coal Mine Disaster Dynamics and Control,China
文摘The differential cubature solution to the problem of a Mindlin plate lying on the Winkler foundation with two simply supported edges and two clamped edges was derived.Discrete numerical technology and shape functions were used to ensure that the solution is suitable to irregular shaped plates.Then,the mechanical model and the solution were employed to model the protection layer that isolates the mining stopes from sea water in Sanshandao gold mine,which is the first subsea mine of China.Furthermore,thickness optimizations for the protection layers above each stope were conducted based on the maximum principle stress criterion,and the linear relations between the best protection layer thickness and the stope area under different safety factors were regressed to guide the isolation design.The method presented in this work provides a practical way to quickly design the isolation layer thickness in subsea mining.
基金Projects(50374075, 50321402) supported by the National Natural Science Foundation of ChinaProject(2004CB619204) supported by the National Basic Research and Development Program of China+1 种基金Project(200549) supported by the Specialized Research Fund of the NationalExcellent PhD Thesis
文摘According to physiological and biochemical characteristics of Leptospirillum ferriphilum, a strain of object bacteria was isolated successfully. Bacteria were enriched by selective liquid medium and plated on designed single-layered agar solid medium. Colony was cultured and bacteria were collected. The morphologies of the object bacteria were observed using crystal violet staining, scanning electron microscope（SEM） and transmission electron microscope （TEM）. The result of 16S rDNA identification shows that this bacterium belongs to Leptospirillum ferriphilum and it is named as Leptospirillum ferriphilum strain D1. These results indicate that this new single-layered agar solid medium is efficient and physiological-biochemical characteristics show that the optimum simple for isolation of Leptospirillum ferriphilum. Additionally, initial pH value and its growth temperature are 1.68 and 40℃.
文摘The micromation and precision of the Micro-Electromechanical System demand that its manufacturing, measuring and assembling must work in a micro-manufacturing platform with good ability to isolate vibrations. This paper develops a vibration isolation system of micro-manufacturing platform. The brains of many kinds of birds can isolate vibrations well, such as woodpecker’s brain. When a woodpecker pecks the wood at the speed as 1.6 times as the velocity of sound, its brain will tolerate the wallop 1 500 times of the weight of itself without any damage. The isolation mechanics and organic texture of woodpecker’s brain that has good isolation characteristics were studied. A structure model of vibration isolation system for the micro-manufacturing platform is established based on the bionics of the bird’s brain vibration isolation mechanism. In order to isolate effectively the high frequency vibrations from the ground, a rubber layer is used to isolate vibrations passively between the micro-manufacturing platform’s pedestal and the ground. This layer corresponds to the cartilage and muscles in the outer meninges of the bird’s brain. The active vibration isolation technique is adopted to isolate vibrations between the micro-manufacturing platform and the pedestal. Air springs are used as elastic components, which correspond to the interspaces between the outer meninges and the encephala of the bird’s brain. Actuators are made of giant magnetostrictive material, and it corresponds to the nerves and neural muscles linking the meninges and the encephala. The actuators and air springs are arranged vertically in parallel to make use of the giant magnetostrictive actuators effectively. The air springs support almost all weight of the micro-manufacturing platform and the giant magnetostrictive actuators support almost no weight. In order to realize high performance to isolate complex micro-vibration, the control method using a three-layer neural network is presented. This vibration control system takes into account the floor disturbance and the direct disturbance acting on the micro-manufacturing platform. The absolute acceleration of the micro-manufacturing platform is used as the performance index of vibration control. The performance of the control system is tested by numerical simulation. Simulation results show that the active vibration isolation system has good isolation performance against the floor disturbance and the direct disturbance acting on the micro-manufacturing platform in all the frequency range.
基金Project(KSCX2-YW-N-043)supported by the Knowledge Innovation Program of the Chinese Academy of Sciences,China
文摘Lonicera caerulea L.fruit is an excellent source of bioactive compounds.An efficient separation method of cyanins is important for the development of many value-added products and functional food ingredients.High-speed counter-current chromatography(HSCCC) was applied to isolate cyanins from Lonicera caerulea fruits with a biphasic solvent system composed of methyl tert-butyl ether/n-butanol/acetonitrile/water/trifluoroacetic acid(2:2:1:5:0.01,volume ratio).1.41 mg of cyanidin 3,5-O-diglucoside,1.08 mg of cyanidin 3-O-rutinoside and 6.38 mg of cyanidin 3-O-glucoside were obtained from 40 mg of crude extract.The purities of these compounds were 95.8%,92.4% and 97.6%,respectively,as identified by high-performance liquid chromatography–diode array detection(HPLC-DAD) and high-performance liquid chromatography-electrospray ionization mass spectrometryn(HPLC-ESI/MSn).In addition,the dominant anthocyanin,cyanidin 3-O-glucoside was demonstrated cytotoxic response of human hepatocarcinoma SMMC-7721 cells,inducing live cancer cell apoptotic by flow cytometric analysis.
基金supported by the Natural Science Foundation of Shannxi Province(2017JQ5016)the Joint Laboratory for Sea Measurement and Control of Aircraft(DOM2016OF011)
文摘The complex systems are often in the structure of multi-operating modes, and the components implementing system functions are different under different operation modes, which results in the problems that components often fail in different operating modes, faults can be only detected in specified operating modes, tests can be available in specified operating modes,and the cost and efficiency of detecting and isolating faults are different under different operating modes and isolation levels. Aiming at these problems, an optimal test selection method for fault detection and isolation in the multi-operating mode system is proposed by using the fault pair coding and rollout algorithm. Firstly,the faults in fault-test correlation matrices under different operating modes are combined to fault-pairs, which is used to construct the fault pair-test correlation matrices under different operating modes.Secondly, the final fault pair-test correlation matrix of the multioperating mode system is obtained by operating the fault pair-test correlation matrices under different operating modes. Based on the final fault pair-test correlation matrix, the necessary tests are selected by the rollout algorithm orderly. Finally, the effectiveness of the proposed method is verified by examples of the optimal test selection in the multi-operating mode system with faults isolated to different levels. The result shows that the proposed method can effectively mine the fault detection and isolation ability of tests and it is suitable for the optimal test selection of the multi-operating mode system with faults isolated to the replacement unit and specific fault.
文摘An application of the multiobjective fault detection and isolation（FDI） approach to an air-breathing hypersonic vehicle（HSV） longitudinal dynamics subject to disturbances is presented.Maintaining sustainable and safe flight of HSV is a challenging task due to its strong coupling effects,variable operating conditions and possible failures of system components.A common type of system faults for aircraft including HSV is the loss of effectiveness of its actuators and sensors.To detect and isolate multiple actuator/sensor failures,a faulty linear parameter-varying（LPV） model of HSV is derived by converting actuator/system component faults into equivalent sensor faults.Then a bank of LPV FDI observers is designed to track individual fault with minimum error and suppress the effects of disturbances and other fault signals.The simulation results based on the nonlinear flexible HSV model and a nominal LPV controller demonstrate the effectiveness of the fault estimation technique for HSV.
基金Project(50621063)supported by the Chinese National Natural Science Foundation for Innovative Research GroupsProject(2004CB619201)supported by the Major State Basic Research Development Program of China
文摘A heterotrophic acidothermophilic bacterial strain,YNTC-1,was isolated from an acidic hot spring in Tengchong,Yunan,China.YNTC-1 grows at pH value of 1.5-8.0 and temperature of 40-70℃,with optimal pH and temperature at 3.0 and 55℃,respectively.The cells of the strain are in shape of short rod,with 1.0-1.2μm in length and 0.7-0.8μm in diameter,and with distinct spores at both poles of each cell.The predominant fatty acids in cellular membrane of the strain are C18:1ω7c.16s rRNA gene analysis reveals that this strain is closely related to Alicyclobacillus sendaiensis,with over 99%sequence similarity.Based on phenotypic and genotypic analyses,YNTC-1 is identified as a member of A.sendaiensis.Considering some important morphological and biochemical differences between strain YNTC-1 and A.sendaiensis ATCC 27009T,YNTC-1 may be proposed to be a novel subspecies of A.sendaiensis.However,this viewpoint has to be confirmed by further studies.Co-bioleaching of pyrite and chalcopyrite with strain YN22,Sulfobacillus thermosulfidooxidans,shows that strain YNTC-1 has no evident influence on bioleaching rates of these two sulphide minerals.
基金Project(50075017) supported by the National Natural Sceince Foundation of China
文摘The lifetime of metal rubber isolator and its characteristics during lifetime experiment were studied. The stepped-up test principle was adopted to study the lifetime of resonant frequency, the breakage form of metal rubber isolator was obtained, and the relation between the energy dissipation, resonant frequency and stiffness was obtained in (available) lifetime of the isolator. Furthermore, the reason for the changes of properties of metal rubber isolator was analyzed with contact model of metal rubber material. The results show that if the resonant amplitude is large, the stiffness of metal rubber isolator will be kept steadily for a long time, its resonant frequency will be stable and the effective working time in the protecting area will be long. The lifetime of metal rubber isolator is more than 1376 h in the experiment. The main failure forms of metal rubber isolator are accumulative wear and breaking of metal wires and spirals. In protecting area the metal rubber isolator can work effectively for a long time, and the effective working time depends on the concrete working condition.
基金Supported by Scientific Research Foundation for Doctors of Northeast Agricultural University (2012RCB27)Postdoctoral Fund of Heilongjiang Provincial Academy of Agricultural Sciences (LRB04-185)
文摘The development and application of spermatogonial stem cell technology have an important significance in animal cloning, preservation of endangered species and spermatogenesis research. In this study, the seminiferous epithlium cells were isolated and purified, the ceils were cryopreserved after identification, and the effects of different purification and cyopreservation methods on bovine testicular cells were studied. The results showed that there were spermatogonial stem cells and sertoli cells in the neonatal bovine seminiferous tubules, differential adherent selection methods could effectively separate these two cell types. Spermatogonial stem cells were positive after AKP, C-kit, and OCT-4 identification; sertoli ceils were positive after oil red O and vimentin identification. Frozen stock solution supplemented with 10% DMSO had the best effect in spermatogonial stem cell cryopreservation, while fxozen stock solution supplemented with 10% of ethylene glycol and 0.1 mmol. L^-1 trehalose had the best effect in sertoli cells crvooreservation.
基金Project(KYLX15_0256)supported by the Funding of Jiangsu Innovation Program for Graduate Education,ChinaProject(SV2015-KF-01)supported by the Open Project of State Key Laboratory for Strength and Vibration of Mechanical Structures,ChinaProject(XZA15003)supported by the Fundamental Research Funds for the Central Universities,China
文摘The displacement feedback with time delay considered is introduced in order to enhance the vibration isolation performance of a high-static-low-dynamic stiffness(HSLDS) vibration isolator. Such feedback is detailedly analyzed from the viewpoint of equivalent damping. Firstly, the primary resonance of the controlled HSLDS vibration isolator subjected to a harmonic force excitation is obtained based on the multiple scales method and further verified by numerical integration. The stability of the primary resonance is subsequently investigated. Then, the equivalent damping is defined to study the effects of feedback gain and time delay on primary resonance. The condition of jump avoidance is obtained with the purpose of eliminating the adverse effects induced by jumps. Finally, the force transmissibility of the controlled HSLDS vibration isolator is defined to evaluate its isolation performance. It is shown that an appropriate choice of feedback parameters can effectively suppress the force transmissibility in resonant region and reduce the resonance frequency. Furthermore, a wider vibration isolation frequency bandwidth can be achieved compared to the passive HSLDS vibration isolator.
文摘Effects of five incubation temperatures (25℃ ,28℃ ,31℃ ,35℃ and 37℃ for 24hours) and four incubation time periods (0.4,16 and 24 hours at 35℃) on isolated microspore culture of Chinese cabbage were studied. The results showed that cultured microspores of Chinese cabbage developed into embryos at all the incubation temperatues from 28℃ to 37℃ ,but the best response to high temperature occured at 35℃. Among the four kinds of time periods, the highest yield of embryos was obtained at the 24h treatment. Therefore, the isolated microspore culture of Chinese cabbege ran be efficiently carried out at 35℃ for 24 hours.
基金Project(2015-GX-108A)supported by Qinghai Provincial Science and Technology Support Program,China
文摘The bottleneck of strontium compounds preparing from celestite is the promotion of Sr/S isolation efficiency.Low energy consumption and zero release method for isolating Sr/S in preparing Sr(OH)2 process from celestite in mild condition was described.Sr element remained in precipitation with formation of Sr(OH)2,while S element entered into leachate with formation of Na2SO4.The effects of initial concentration of NaOH,conversion temperature,liquid-to-solid(L/S)ratio and conversion time on Sr/S ratio of samples for celestite conversion were systematically investigated by experiments.The results demonstrated that the efficiency of Sr/S isolation increased with the initial concentration of NaOH,L/S ratio and conversion time,and decreased with conversion temperature.The maximum conversion ratio of Sr(OH)2 was 93.88%under the optimum condition,whose Sr/S ratio of sample could reach to 41.16.It illustrated that better isolation efficiency of celestite could be achieved in alkaline treatment.The results of SEM-EDS analyses demonstrated that the conversion reaction was a dissolution-precipitation process.
基金Project(50675042) supported by the National Natural Science Foundation of China
文摘A model to describe the hysteresis damping characteristic of rubber material was presented.It consists of a parallel spring and damper,whose coefficients change with the vibration amplitude and frequency.In order to acquire these relations,force decomposition was carried out according to some sine vibration measurement data of nonlinear forces changing with the deformation of the rubber material.The nonlinear force is decomposed into a spring force and a damper force,which are represented by the amplitude-and frequency-dependent spring and damper coefficients,respectively.Repeating this step for different measurements gives different coefficients corresponding to different amplitudes and frequencies.Then,the application of a parameter identification method provides the requested approximation functions over amplitude and frequency.Using those formulae,as an example,the dynamic characteristic of a hollow shaft system supported by rubber rings was analyzed and the acceleration response curve in the centroid position was calculated.Comparisons with the sine vibration experiments of the real system show a maximal inaccuracy of 8.5%.Application of this model and procedure can simplify the modeling and analysis of mechanical systems including rubber materials.
基金Projects(51308549,51378504,51478475) supported by the National Natural Science Foundation of ChinaProject(2015JJ3159) supported by the Natural Science Foundation of Hunan Province,ChinaProject(2015CX006) supported by the Innovation-driven Plan in Central South University,China
文摘By taking a rolling-spring isolation system as the study object, the effects of the non-uniform distribution of rolling friction coefficient on its isolation performance were analyzed by a compiled computer program. The results show that the errors associated with the structural maximum relative displacement, acceleration and residual displacement due to ignoring the friction variability sequentially grow. This rule is weakened by the spring action, however, the unreasonable spring constant will cause sympathetic vibration. Under the condition of large friction variability, in the calculation of the structural maximum relative displacement and acceleration, the friction variability should be considered. When the structural residual displacement is concerned, the variability of rolling friction coefficient should be fully considered regardless of the friction variability.
基金Projects(40776035, 40376036) supported by the National Natural Science Foundation of ChinaProject(DY105-02-04-05) supported by the China Ocean Mineral Resources Research and Development Association+2 种基金Project(07MX27) supported by the Mittal Student FoundationProject (2340-74236000003) supported by the Post-graduate Foundation of Hunan Province, ChinaProject (200805330053) supported by the Doctoral Foundation of Ministry of Education of China
文摘A facultative heterotrophic strain （DS-0205） was isolated from a deep-sea sediment sample collected at a depth of 5.2 km in the eastern Pacific Ocean, China. Strain DS-0205 is motile helmet-like single cell or pairs, forming hemisphere with the center sunken of variable size. It has a widespread carbon source and nitrogen source, including agarose, citric acid, salicin, D-glucitol nitrate, sodium nitrite and cthylamine, tt can grow in the following environment： temperature 4-37℃, pH 2.0-12.0, tolerance to NaCl≤15%. Two phylogenetic trees, one based on the ITS and 5.8S rRNA sequences and the other based on the 18S rRNA sequences, unite strain DS-0205（=JCM 0205） to the type strain of Rhodosporidium diobovatum JCM 3787 through a considerable evolutionary distance. These results suggest that strain DS-0205 is a new strain of the Rhodosporidium diobovatum.
