In this paper,we present a phase multiplication algorithm(PMA)to obtain scalable fringe precision in laser self-mixing interferometer under a weak feedback regime.Merely by applying the double angle formula on the sel...In this paper,we present a phase multiplication algorithm(PMA)to obtain scalable fringe precision in laser self-mixing interferometer under a weak feedback regime.Merely by applying the double angle formula on the self-mixing signal multiple times,the continuously improved fringe precision will be obtained.Theoretical analysis shows that the precision of the fringe could be improved toλ/2^(n+1).The validity of the proposed method is demonstrated by means of simulated SMI signals and confirmed by experiments under different amplitudes.A fringe precision ofλ/128 at a sampling rate of 500 k S/s has been achieved after doing 6 th the PMA.Finally,an amplitude of 50 nm has been proved to be measurable and the absolute error is 3.07 nm,which is within the theoretical error range.The proposed method for vibration measurement has the advantage of high accuracy and reliable without adding any additional optical elements in the optical path,thus it will play an important role in nanoscale measurement field.展开更多
To satisfy the multiple priority requests from buses that arrive at different phases within a small time window, a multi-phase bus signal priority (MPBSP) strategy is developed. The proximity principle is brought fo...To satisfy the multiple priority requests from buses that arrive at different phases within a small time window, a multi-phase bus signal priority (MPBSP) strategy is developed. The proximity principle is brought forward to settle the conflicts among multiple priority requests and arrange the optimal priority sequence. To avoid over saturation of the intersection, a conditional MPBSP algorithm that adopts early green and green extension strategies is developed to give priority to the bus with the highest priority level when green time that each phase runs makes its saturation degree not larger than 0. 95. Finally, the algorithm is tested in the VISSIM environment and compared with the normal signal timing algorithm. Sensitive analysis of the number of priority phases, bus demand, and volume to capacity ratios are conducted to quantify their impacts on the benefits of the MPBSP. Results show that the MPBSP strategy can effectively reduce bus delays, and with the increase in the number of priority phases, the reduction range of bus delays also increases.展开更多
A number of E-W trending subparallel mafic dikes of diabase composition occurred in Gyangze-Kangma area,eastern Tethyan Himalaya,southern Tibet.They intruded into the Tethyan Himalaya sedimentary sequence.Whether they...A number of E-W trending subparallel mafic dikes of diabase composition occurred in Gyangze-Kangma area,eastern Tethyan Himalaya,southern Tibet.They intruded into the Tethyan Himalaya sedimentary sequence.Whether they belong to the;32 Ma Comei LIP(Zhu et al.,2009)or展开更多
A new continuous multi-phase transformation field model was established for liquid-solid-eutectoid transformation. Taking Fe-C alloy as an example, the model was used to simulate the evolution of the micro-morphology ...A new continuous multi-phase transformation field model was established for liquid-solid-eutectoid transformation. Taking Fe-C alloy as an example, the model was used to simulate the evolution of the micro-morphology of the liquid-solid phase transition, and the effects of temperature, solute and free energy on the nucleation of pearlite after the liquid-solid phase transition were analyzed. The micro-morphology of pearlite was simulated. The simulation results show that the austenite structure has hereditary effect on the pearlite, the morphology of pearlite structure was similar to that of the parent austenite. The eutectoid structure at the front of pearlite grows toward the interior of austenite grains in a bifurcation manner and in the spherical coronal shape. In addition, the growth rate of pearlite was related to the shape of concave-convex interface at the nucleation site, and the growth rate at the convex interface was faster than that at the concave interface.展开更多
We study the synchronization dynamics in a system of multiple interacting populations of phase oscillators. Using the dimensionality-reduction technique of Ott and Antonsen, we explore different types of synchronizati...We study the synchronization dynamics in a system of multiple interacting populations of phase oscillators. Using the dimensionality-reduction technique of Ott and Antonsen, we explore different types of synchronization dynamics when the incoherent state becomes unstable. We find that the inter-population coupling is crucial to the synchronization. When the intra-population interaction is repulsive, the local synchronization can still be maintained through the inter-population coupling. For attractive inter-population coupling, the local order parameters in different populations are of in-phase while the local synchronization are of anti-phase for repulsive inter-population coupling.展开更多
Based on the vector diffraction theory, the effect of complex phase filters on intensity distribution of a radially polarized multi Gaussian beam in the focal region of high NA lens is theoretically investigated. It i...Based on the vector diffraction theory, the effect of complex phase filters on intensity distribution of a radially polarized multi Gaussian beam in the focal region of high NA lens is theoretically investigated. It is observed that a properly designed multi belt complex phase filter can generate subwavelength novel focal patterns including splitting of focal spots and generation of multiple focal spot segments such as eight, six and four focal spots along the optical axis are obtained. We expect that such an investigation is useful for optical manipulation and material processing, multiple high refractive index particle trapping technologies.展开更多
To address the relatively mediocre mechanical properties of single-phase multi-component carbide ceramics,a phase transition from a single phase to multiple phases was proposed to achieve superior mechanical propertie...To address the relatively mediocre mechanical properties of single-phase multi-component carbide ceramics,a phase transition from a single phase to multiple phases was proposed to achieve superior mechanical properties.A series of(TiZrV_(x)Nb)C_(0.8) ceramics with different V contents were fabricated by spark plasma sintering(SPS).The influence of the V content on the phase composition,microstructural evolution,and mechanical properties was investigated in detail.The transition behavior from a single phase to multiple phases is discovered and discussed.The formation of the Zr-rich phase and Zr-poor phase can be attributed to the increase in lattice distortion and mixed enthalpy caused by the addition of V.A nanometer lamellar structure with a semi-coherent interface obtained via in situ decomposition is reported for the first time in multi-component carbide ceramics.The semi-coherent interfaces with high dislocation density and strain concentration effectively improve the mechanical properties,grain refinement,and multi-phase formation.The optimal comprehensive mechanical properties of the Vickers hardness(26.3 GPa),flexural strength(369 MPa),and fracture toughness(3.1 MPa·m^(1/2))were achieved for the sample with 20 mol%V.展开更多
The Henry's Law constant (k) for phosphine in seawater was determined by multiple phase equilibration combined with headspace gas chromatography. The effects of pH, temperature, and salinity on k were studied. The ...The Henry's Law constant (k) for phosphine in seawater was determined by multiple phase equilibration combined with headspace gas chromatography. The effects of pH, temperature, and salinity on k were studied. The k value for phosphine in natural seawater was 6.415 at room temperature (approximately 23℃). This value increases with increases in temperature and salinity, but no obvious change was observed at different pH levels. At the same temperature, there was no significant difference between the k for phosphine in natural seawater and that in artificial seawater. This implies that temperature and salinity are major determining factors for k in marine environment. Double linear regression with Henry's Law constants for phosphine as a function of temperature and salinity confirmed our observations. These results provide a basis for the measurement of trace phosphine concentrations in seawater, and will be helpful for future research on the status of phosphine in the oceanic biogeochemical cycle of phosphorus.展开更多
The aim of this investigation is to research the initial ignition of the underwater-launching solid rocket motor.The MIXTURE multiple-phase model was set to simulate the initial ignition.The water vaporization was res...The aim of this investigation is to research the initial ignition of the underwater-launching solid rocket motor.The MIXTURE multiple-phase model was set to simulate the initial ignition.The water vaporization was researched and the energy transfer was added to the energy equations.The flow field and the vaporization were calculated coupled.The initial ignition process of the underwater solid rocket motor is obtained and the vaporization influence to the underwater launching is analyzed.The "neck","inverted jet" and "eruption" phenomenon of the bubble are observed.The bubble increases more rapidly because the steam mass added to the fuel.The temperature is lower considering the vaporization because the steam enthalpy is lower than the fuel enthalpy and the flow field of the initial ignition of the underwater-launching solid rocket motor is accordant well to the reference.展开更多
This article describes mathematical models for phase separated mixtures of materials that are in pressure and velocity equilibrium but not necessarily temperature equilibrium. General conditions for constitutive model...This article describes mathematical models for phase separated mixtures of materials that are in pressure and velocity equilibrium but not necessarily temperature equilibrium. General conditions for constitutive models for such mixtures that exhibit a single mixture sound speed are discussed and specific examples are described.展开更多
The traditional crack exploring method with echo (reflected wave) in metals is called the "single-wave detecting method" that uses a probe of single weight. This method is not able to detect directly the size and ...The traditional crack exploring method with echo (reflected wave) in metals is called the "single-wave detecting method" that uses a probe of single weight. This method is not able to detect directly the size and shape of the crack and the result can only be obtained by relative comparison, that is to compare the echo amplitudes of the unknown quantity (crack) with the known quantity (regular artificial crack) to determine the equivalent size and shape of a certain crack.展开更多
In this paper,the advantage of using numerical models with the strength reduction method(SRM) to evaluate entry stability in complex multiple-seam conditions is demonstrated.A coal mine under variable topography from ...In this paper,the advantage of using numerical models with the strength reduction method(SRM) to evaluate entry stability in complex multiple-seam conditions is demonstrated.A coal mine under variable topography from the Central Appalachian region is used as a case study.At this mine,unexpected roof conditions were encountered during development below previously mined panels.Stress mapping and observation of ground conditions were used to quantify the success of entry support systems in three room-and-pillar panels.Numerical model analyses were initially conducted to estimate the stresses induced by the multiple-seam mining at the locations of the affected entries.The SRM was used to quantify the stability factor of the supported roof of the entries at selected locations.The SRM-calculated stability factors were compared with observations made during the site visits,and the results demonstrate that the SRM adequately identifies the unexpected roof conditions in this complex case.It is concluded that the SRM can be used to effectively evaluate the likely success of roof supports and the stability condition of entries in coal mines.展开更多
The characterization of multiple iron-rich phases in high-pressure die-cast AlSi10MnMg alloy was studied.Attention was focused on the formation and fracture behavior of the primary iron-rich phase((P-IMC)_(I))formed i...The characterization of multiple iron-rich phases in high-pressure die-cast AlSi10MnMg alloy was studied.Attention was focused on the formation and fracture behavior of the primary iron-rich phase((P-IMC)_(I))formed in the shot sleeve and plate-shaped eutectic iron-rich phase in high-pressure die cast(HPDC)AlSi10MnMg alloy.Results show that multiple types of iron-rich phases with various morphologies,in-cluding primary iron-rich phases(polyhedral(P-IMC)_(I) and(P-IMC)_(II))and eutectic iron-rich phases(plate-shaped,net shape,and fish-bone shape),were found in HPDC AlSi10MnMg.Coarse(P-IMC)_(I) formed in the shot sleeve were distributed in the interface between primaryα-Al and binary Al-Si eutectic.Small size(P-IMC)_(II) and various eutectic iron-rich phases formed in the die cavity and they were distributed in Al-Si binary eutectic.The primary iron-rich phases belonged to a simple cubic crystal structure with a lattice constant a=1.265 nm and they exhibited a lateral growth characteristic with a termination of{110}surface.βphase was surrounded byδphase and they coexisted in a plate-shaped iron-rich phase.High-density stacking fault inβphase andδ/βinterface provided an excellent nucleation site forδphase.From mechanical behavior,the stress concentration caused by eutectic iron-rich phases was far less than(P-IMC)_(I) and it would not cause crack initiation along the eutectic cluster boundary.In addition,(P-IMC)_(I) showed the worst deformation coordination with primaryα-Al while the plate-shaped eutectic iron-rich phase exhibited similar deformation characteristics with silicon particles.展开更多
The impacts of ionospheric scintillation on geosynchronous synthetic aperture radar(GEO SAR)focusing is studied based on the multiple phase screen(MPS)theory.The power spectrum density of electron irregularities i...The impacts of ionospheric scintillation on geosynchronous synthetic aperture radar(GEO SAR)focusing is studied based on the multiple phase screen(MPS)theory.The power spectrum density of electron irregularities is first modified according to the ionospheric anisotropy.Then propagation wave equations in random medium are deduced in the case of oblique incidence in GEO SAR.The amplitude and phase errors induced by the random electron fluctuations are generated by the iterated MPS simulations and are superimposed into the GEO SAR signals.Through the following imaging and evaluation,the effects of the anisotropic ionospheric scintallition on GEO SAR are assessed.At last,the optimized integration time under different ionospheric scintillation conditions are recommended through Monte Carlo experiments.It is concluded that,greater ionospheric fluctuations and longer integration time will result in more severe deterioration,even no focus at all in the worst case.展开更多
This paper presents a semi-blind tracking algorithm used for Multiple Phase Shift Keying based Orthogonal Frequency Division Multiplexing(MPSK-OFDM) system. By using special pream-bles to assist the decision of a feed...This paper presents a semi-blind tracking algorithm used for Multiple Phase Shift Keying based Orthogonal Frequency Division Multiplexing(MPSK-OFDM) system. By using special pream-bles to assist the decision of a feedback loop and to solve the problem of phase ambiguity,the tracking performance of the algorithm has been improved greatly. Only a few preambles are needed in the al-gorithm since the preambles are not used to estimate the frequency offset but used to provide the variation information of the phase due to the presence of frequency offset. Simulations verify that the algorithm has low SNR bound for tracking as well as high tracking accuracy and the tracking range is expanded to 30% of one subcarrier spacing.展开更多
The research was done at Havana Biofabric, Mayabeque Province. The vitro plants of banana (Musa sp) used came from the clone Enano Guantanamero (viand type). They come from multiplication phase in a Murashige and ...The research was done at Havana Biofabric, Mayabeque Province. The vitro plants of banana (Musa sp) used came from the clone Enano Guantanamero (viand type). They come from multiplication phase in a Murashige and MS (Skoog medium). The objective of this work was to study the potentialities of HA (humic acids) for stimulation of rooting and cell division process, searching for completely synthetic hormone substitution due to its high cost. The multiplication medium contained thiamine (2 mg·L^-1), myo-inositol (100 mg·L^-1), sugar (30mg·L^-1). By the use of HA, five treatments were used with total substitution of auxin and cytokinin (TI: HA (10 mg.Ll); (T2: HA (20 mg·L^-1); (T3: HA (30mg·L^-1); (T4: HA (40 mg·L^-1); (T5: HA (50 mg·L^-1) and the control with 6BAP (benzil amino purine) (4 mg·L^-1) + IBA (indol butyric acid) (0.65 mg·L^-1), pH of the medium was adjust just before agar were add. The results showed that in the explants under HA treatments, elongation and cell multiplication were favored confirmed by explants great high, root number and length due to dry mass. The total protein content, reduced carbohydrate and peroxidases enzymatic activity were determine. The use of Vermicompost HA in the in vitro micropropagation of banana allow the elimination of rooting phase saving materials and be able to pass explants directly to Acclimatization phase.展开更多
We describe the point spectrum of the operator which corresponds to the M/M/1 queueing model with vacations and multiple phases of operation.Then by using this result we prove that the essential growth bound of the C0...We describe the point spectrum of the operator which corresponds to the M/M/1 queueing model with vacations and multiple phases of operation.Then by using this result we prove that the essential growth bound of the C0-semigroup generated by the operator is 0,the C0-semigroup is not compact,not eventually compact,even not quasi-compact.Moreover,we verify that it is impossible that the time-dependent solution of the M/M/1 queueing model with vacations and multiple phases of operation exponentially converges to its steady-state solution.In addition,we obtain the spectral radius and essential spectral radius of the C0-semigroup.Lastly,we discuss other spectrum of the operator and obtain a set which belongs to the union of its continuous spectrum and residual spectrum.展开更多
Phase separations have been studied for graded-indium content In_xGa_(1-x)N/GaN multiple quantum wells(MQWs) with different indium contents by means of photoluminescence(PL),cathodeluminescence(CL) and time-re...Phase separations have been studied for graded-indium content In_xGa_(1-x)N/GaN multiple quantum wells(MQWs) with different indium contents by means of photoluminescence(PL),cathodeluminescence(CL) and time-resolved PL(TRPL) techniques.Besides the main emission peaks,all samples show another 2 peaks at the high and low energy parts of the main peaks in PL when excited at 10 K.CL images show a clear contrast for 3 samples,which indicates an increasing phase separation with increasing indium content.TRPL spectra at 15 K of the main emissions show an increasing delay of rising time with indium content,which means a carrier transferring from low indium content structures to high indium content structures.展开更多
Objective: To investigate the level of acute phase proteins (APP)-synthesized in hepatocytes in pathogenic process of multiple organ dysfunction syndrome (MODS) and the effect of Dachengqi Decoction (DCQD) on it. Met...Objective: To investigate the level of acute phase proteins (APP)-synthesized in hepatocytes in pathogenic process of multiple organ dysfunction syndrome (MODS) and the effect of Dachengqi Decoction (DCQD) on it. Methods: The levels of C-reactive protein (CRP),α1-acid glycoprotein (AAG), α1-antitrypsin total (α1AT), α2-macroglobulin (α2-MG), ceruloplasmine (CP), hepatoglobin (HP) and transferrin (TF) synthesis were determined in 32 cases of MODS patients and rat models of MODS induced by acute infective peritonitis and mesenterial artery ischemia-reperfusion.Results: The serum APP level in MODS patients was increased and higher than that in the control group (P < 0. 01 ). After 3 days of DCQD treatment it reduced significantly (P <0. 05). Serum APP level in MODS model was also increased significantly, and after 3 days of DCQD treatment, it reduced significantly (P < 0. 05). The APP secreting level of rat hepatocytes cultured in vitro raised after stimulated and activated by lipopolysacchride, which was reduced after cultured with rabbits serum containing different concentration of effective ingredients of DCQD. The APP inhibiting effect of DCQD was dose dependent. Conclusion: Purgation therapy with DCQD could reduce the stimulation of pathogenic factors on hepatocytes, protect tissues and organs from damage caused by excessive inflammatory reaction.Original article on CJIM(Chin) 1998; 18(8): 453展开更多
Recently,the two-dimensional(2D)ruddlesden-popper(RPP)perovskite has been successfully attracting great attention owing to their excellent electronic property and superior ambient stability.But 2D perovskite solar cel...Recently,the two-dimensional(2D)ruddlesden-popper(RPP)perovskite has been successfully attracting great attention owing to their excellent electronic property and superior ambient stability.But 2D perovskite solar cells(PVSCs)with insulating large cations show a worse performance than three-dimensional(3D)PVSCs in general because of the worse charge transportation.In this work,dimethyl sulfoxide(DMSO)and KI were incorporated simultaneously to produce a synergistic effect on both film quality and orientation of 2D perovskite.With this strategy,a cavity-free 2D perovskite film was formed with vertically oriented crystal,and high quality film was obtained with decreased defects and increased crystallinity.Besides,profitable multiple phases were obtained for better spontaneous carrier separation and transportation.The 2D PVSCs based on(PEA)2(MA)n−1PbnI3n+1(n=5)delivered a higher power conversion efficiency(PCE)of 13.4%.In addition,the perovskite with KI and DMSO contained more stable low-dimension phase at the bottom of perovskite film,which could act as a barrier to prevent moisture from further eroding internal perovskites.The optimized 2D PVSCs remained 90%of the PCE after being exposed in air(50%–60%humidity,room temperature)with a continuous illumination for 300 h.展开更多
基金supported by the Natural Science Foundation of Fujian Province(No.2020J01705)the School Foundation of Jimei University(No.C150345)。
文摘In this paper,we present a phase multiplication algorithm(PMA)to obtain scalable fringe precision in laser self-mixing interferometer under a weak feedback regime.Merely by applying the double angle formula on the self-mixing signal multiple times,the continuously improved fringe precision will be obtained.Theoretical analysis shows that the precision of the fringe could be improved toλ/2^(n+1).The validity of the proposed method is demonstrated by means of simulated SMI signals and confirmed by experiments under different amplitudes.A fringe precision ofλ/128 at a sampling rate of 500 k S/s has been achieved after doing 6 th the PMA.Finally,an amplitude of 50 nm has been proved to be measurable and the absolute error is 3.07 nm,which is within the theoretical error range.The proposed method for vibration measurement has the advantage of high accuracy and reliable without adding any additional optical elements in the optical path,thus it will play an important role in nanoscale measurement field.
基金The National High Technology Research and Development Program of China(863 Program)(No.2011AA110304)the National Natural Science Foundation of China(No.50908100)Graduate Innovation Fund of Jilin University(No.20111044)
文摘To satisfy the multiple priority requests from buses that arrive at different phases within a small time window, a multi-phase bus signal priority (MPBSP) strategy is developed. The proximity principle is brought forward to settle the conflicts among multiple priority requests and arrange the optimal priority sequence. To avoid over saturation of the intersection, a conditional MPBSP algorithm that adopts early green and green extension strategies is developed to give priority to the bus with the highest priority level when green time that each phase runs makes its saturation degree not larger than 0. 95. Finally, the algorithm is tested in the VISSIM environment and compared with the normal signal timing algorithm. Sensitive analysis of the number of priority phases, bus demand, and volume to capacity ratios are conducted to quantify their impacts on the benefits of the MPBSP. Results show that the MPBSP strategy can effectively reduce bus delays, and with the increase in the number of priority phases, the reduction range of bus delays also increases.
基金supported by National Science Foundation of China (Grant No. 41425010 & 41503023)China Geological Survey (Grant No. 12120114022701 & 12120115027101)
文摘A number of E-W trending subparallel mafic dikes of diabase composition occurred in Gyangze-Kangma area,eastern Tethyan Himalaya,southern Tibet.They intruded into the Tethyan Himalaya sedimentary sequence.Whether they belong to the;32 Ma Comei LIP(Zhu et al.,2009)or
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.:11504149,51661020)thc Natural Scicnce Toundation of Gansu Province of China(Grant No:18JR3RA147).
文摘A new continuous multi-phase transformation field model was established for liquid-solid-eutectoid transformation. Taking Fe-C alloy as an example, the model was used to simulate the evolution of the micro-morphology of the liquid-solid phase transition, and the effects of temperature, solute and free energy on the nucleation of pearlite after the liquid-solid phase transition were analyzed. The micro-morphology of pearlite was simulated. The simulation results show that the austenite structure has hereditary effect on the pearlite, the morphology of pearlite structure was similar to that of the parent austenite. The eutectoid structure at the front of pearlite grows toward the interior of austenite grains in a bifurcation manner and in the spherical coronal shape. In addition, the growth rate of pearlite was related to the shape of concave-convex interface at the nucleation site, and the growth rate at the convex interface was faster than that at the concave interface.
文摘We study the synchronization dynamics in a system of multiple interacting populations of phase oscillators. Using the dimensionality-reduction technique of Ott and Antonsen, we explore different types of synchronization dynamics when the incoherent state becomes unstable. We find that the inter-population coupling is crucial to the synchronization. When the intra-population interaction is repulsive, the local synchronization can still be maintained through the inter-population coupling. For attractive inter-population coupling, the local order parameters in different populations are of in-phase while the local synchronization are of anti-phase for repulsive inter-population coupling.
文摘Based on the vector diffraction theory, the effect of complex phase filters on intensity distribution of a radially polarized multi Gaussian beam in the focal region of high NA lens is theoretically investigated. It is observed that a properly designed multi belt complex phase filter can generate subwavelength novel focal patterns including splitting of focal spots and generation of multiple focal spot segments such as eight, six and four focal spots along the optical axis are obtained. We expect that such an investigation is useful for optical manipulation and material processing, multiple high refractive index particle trapping technologies.
基金the National Natural Science Foundation of China (Nos. 52032002, 52372060, 51972081, and U22A20128)the National Safety Academic Foundation (No. U2130103)+4 种基金the National Key R&D Program of China (No. 2021YFB3701400)the China Postdoctoral Science Foundation (No. 2023M730839)the Heilongjiang Postdoctoral Fund (No. LBH-Z22025)the National Key Laboratory of Precision Hot Processing of Metals (No. 61429092300305)the Heilongjiang Touyan Team Program are gratefully acknowledged. The authors thank Professor Suk-Joong L. Kang (Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Republic of Korea) for his assistance in editing. The support of the thermodynamic calculations with FactSage software provided by Professor Yudong Fu (College of Material Science and Chemical Engineering, Harbin Engineering University, China) is also acknowledged.
文摘To address the relatively mediocre mechanical properties of single-phase multi-component carbide ceramics,a phase transition from a single phase to multiple phases was proposed to achieve superior mechanical properties.A series of(TiZrV_(x)Nb)C_(0.8) ceramics with different V contents were fabricated by spark plasma sintering(SPS).The influence of the V content on the phase composition,microstructural evolution,and mechanical properties was investigated in detail.The transition behavior from a single phase to multiple phases is discovered and discussed.The formation of the Zr-rich phase and Zr-poor phase can be attributed to the increase in lattice distortion and mixed enthalpy caused by the addition of V.A nanometer lamellar structure with a semi-coherent interface obtained via in situ decomposition is reported for the first time in multi-component carbide ceramics.The semi-coherent interfaces with high dislocation density and strain concentration effectively improve the mechanical properties,grain refinement,and multi-phase formation.The optimal comprehensive mechanical properties of the Vickers hardness(26.3 GPa),flexural strength(369 MPa),and fracture toughness(3.1 MPa·m^(1/2))were achieved for the sample with 20 mol%V.
基金Supported by the National Natural Science Foundation of China (Nos.30970522,40576058)the National Natural Science Foundation of China for Creative Research Groups (No.41121064)
文摘The Henry's Law constant (k) for phosphine in seawater was determined by multiple phase equilibration combined with headspace gas chromatography. The effects of pH, temperature, and salinity on k were studied. The k value for phosphine in natural seawater was 6.415 at room temperature (approximately 23℃). This value increases with increases in temperature and salinity, but no obvious change was observed at different pH levels. At the same temperature, there was no significant difference between the k for phosphine in natural seawater and that in artificial seawater. This implies that temperature and salinity are major determining factors for k in marine environment. Double linear regression with Henry's Law constants for phosphine as a function of temperature and salinity confirmed our observations. These results provide a basis for the measurement of trace phosphine concentrations in seawater, and will be helpful for future research on the status of phosphine in the oceanic biogeochemical cycle of phosphorus.
文摘The aim of this investigation is to research the initial ignition of the underwater-launching solid rocket motor.The MIXTURE multiple-phase model was set to simulate the initial ignition.The water vaporization was researched and the energy transfer was added to the energy equations.The flow field and the vaporization were calculated coupled.The initial ignition process of the underwater solid rocket motor is obtained and the vaporization influence to the underwater launching is analyzed.The "neck","inverted jet" and "eruption" phenomenon of the bubble are observed.The bubble increases more rapidly because the steam mass added to the fuel.The temperature is lower considering the vaporization because the steam enthalpy is lower than the fuel enthalpy and the flow field of the initial ignition of the underwater-launching solid rocket motor is accordant well to the reference.
基金supported by the Los Alamos National Laboratory,an affir mative action/equal opportunity employer,operated by Los Alamos National Security,LLC,for the National Nuclear Security Administration of the U.S.Department of Energy under contract DE-AC52-06NA25396
文摘This article describes mathematical models for phase separated mixtures of materials that are in pressure and velocity equilibrium but not necessarily temperature equilibrium. General conditions for constitutive models for such mixtures that exhibit a single mixture sound speed are discussed and specific examples are described.
基金National Natural Science Fundation of China (60172061).
文摘The traditional crack exploring method with echo (reflected wave) in metals is called the "single-wave detecting method" that uses a probe of single weight. This method is not able to detect directly the size and shape of the crack and the result can only be obtained by relative comparison, that is to compare the echo amplitudes of the unknown quantity (crack) with the known quantity (regular artificial crack) to determine the equivalent size and shape of a certain crack.
文摘In this paper,the advantage of using numerical models with the strength reduction method(SRM) to evaluate entry stability in complex multiple-seam conditions is demonstrated.A coal mine under variable topography from the Central Appalachian region is used as a case study.At this mine,unexpected roof conditions were encountered during development below previously mined panels.Stress mapping and observation of ground conditions were used to quantify the success of entry support systems in three room-and-pillar panels.Numerical model analyses were initially conducted to estimate the stresses induced by the multiple-seam mining at the locations of the affected entries.The SRM was used to quantify the stability factor of the supported roof of the entries at selected locations.The SRM-calculated stability factors were compared with observations made during the site visits,and the results demonstrate that the SRM adequately identifies the unexpected roof conditions in this complex case.It is concluded that the SRM can be used to effectively evaluate the likely success of roof supports and the stability condition of entries in coal mines.
基金supported by the Major Science and Technology Project of Changchun City,Jilin Province(No.20210301024GX)the National Natural Science Foundation of China(No.52175335)The authors also appreciate the help pro-vided by China FAW Foundry Co.,LTD and Germany ALUMINUM RHEINFELDEN Group.
文摘The characterization of multiple iron-rich phases in high-pressure die-cast AlSi10MnMg alloy was studied.Attention was focused on the formation and fracture behavior of the primary iron-rich phase((P-IMC)_(I))formed in the shot sleeve and plate-shaped eutectic iron-rich phase in high-pressure die cast(HPDC)AlSi10MnMg alloy.Results show that multiple types of iron-rich phases with various morphologies,in-cluding primary iron-rich phases(polyhedral(P-IMC)_(I) and(P-IMC)_(II))and eutectic iron-rich phases(plate-shaped,net shape,and fish-bone shape),were found in HPDC AlSi10MnMg.Coarse(P-IMC)_(I) formed in the shot sleeve were distributed in the interface between primaryα-Al and binary Al-Si eutectic.Small size(P-IMC)_(II) and various eutectic iron-rich phases formed in the die cavity and they were distributed in Al-Si binary eutectic.The primary iron-rich phases belonged to a simple cubic crystal structure with a lattice constant a=1.265 nm and they exhibited a lateral growth characteristic with a termination of{110}surface.βphase was surrounded byδphase and they coexisted in a plate-shaped iron-rich phase.High-density stacking fault inβphase andδ/βinterface provided an excellent nucleation site forδphase.From mechanical behavior,the stress concentration caused by eutectic iron-rich phases was far less than(P-IMC)_(I) and it would not cause crack initiation along the eutectic cluster boundary.In addition,(P-IMC)_(I) showed the worst deformation coordination with primaryα-Al while the plate-shaped eutectic iron-rich phase exhibited similar deformation characteristics with silicon particles.
基金Supported by the National Natural Science Foundation of China(61225005,61427802,61471038,61120106004)Chang Jiang Scholars Program(T2012122)+1 种基金111 project of China(B14010)Beijing Higher Education Young Elite Teacher Project(YETP1168)
文摘The impacts of ionospheric scintillation on geosynchronous synthetic aperture radar(GEO SAR)focusing is studied based on the multiple phase screen(MPS)theory.The power spectrum density of electron irregularities is first modified according to the ionospheric anisotropy.Then propagation wave equations in random medium are deduced in the case of oblique incidence in GEO SAR.The amplitude and phase errors induced by the random electron fluctuations are generated by the iterated MPS simulations and are superimposed into the GEO SAR signals.Through the following imaging and evaluation,the effects of the anisotropic ionospheric scintallition on GEO SAR are assessed.At last,the optimized integration time under different ionospheric scintillation conditions are recommended through Monte Carlo experiments.It is concluded that,greater ionospheric fluctuations and longer integration time will result in more severe deterioration,even no focus at all in the worst case.
基金the Natural Science Foundation of Jiangsu Province (BK2006701)the National Natural Science Foundation of China (No.60672079).
文摘This paper presents a semi-blind tracking algorithm used for Multiple Phase Shift Keying based Orthogonal Frequency Division Multiplexing(MPSK-OFDM) system. By using special pream-bles to assist the decision of a feedback loop and to solve the problem of phase ambiguity,the tracking performance of the algorithm has been improved greatly. Only a few preambles are needed in the al-gorithm since the preambles are not used to estimate the frequency offset but used to provide the variation information of the phase due to the presence of frequency offset. Simulations verify that the algorithm has low SNR bound for tracking as well as high tracking accuracy and the tracking range is expanded to 30% of one subcarrier spacing.
文摘The research was done at Havana Biofabric, Mayabeque Province. The vitro plants of banana (Musa sp) used came from the clone Enano Guantanamero (viand type). They come from multiplication phase in a Murashige and MS (Skoog medium). The objective of this work was to study the potentialities of HA (humic acids) for stimulation of rooting and cell division process, searching for completely synthetic hormone substitution due to its high cost. The multiplication medium contained thiamine (2 mg·L^-1), myo-inositol (100 mg·L^-1), sugar (30mg·L^-1). By the use of HA, five treatments were used with total substitution of auxin and cytokinin (TI: HA (10 mg.Ll); (T2: HA (20 mg·L^-1); (T3: HA (30mg·L^-1); (T4: HA (40 mg·L^-1); (T5: HA (50 mg·L^-1) and the control with 6BAP (benzil amino purine) (4 mg·L^-1) + IBA (indol butyric acid) (0.65 mg·L^-1), pH of the medium was adjust just before agar were add. The results showed that in the explants under HA treatments, elongation and cell multiplication were favored confirmed by explants great high, root number and length due to dry mass. The total protein content, reduced carbohydrate and peroxidases enzymatic activity were determine. The use of Vermicompost HA in the in vitro micropropagation of banana allow the elimination of rooting phase saving materials and be able to pass explants directly to Acclimatization phase.
基金the National Natural Science Foundation of China (Grant No. 11961062)。
文摘We describe the point spectrum of the operator which corresponds to the M/M/1 queueing model with vacations and multiple phases of operation.Then by using this result we prove that the essential growth bound of the C0-semigroup generated by the operator is 0,the C0-semigroup is not compact,not eventually compact,even not quasi-compact.Moreover,we verify that it is impossible that the time-dependent solution of the M/M/1 queueing model with vacations and multiple phases of operation exponentially converges to its steady-state solution.In addition,we obtain the spectral radius and essential spectral radius of the C0-semigroup.Lastly,we discuss other spectrum of the operator and obtain a set which belongs to the union of its continuous spectrum and residual spectrum.
基金Project supported by the National Natural Science Foundation of China(No.11174241)the Natural Science Foundation of Shandong Province,China(No.2009VRA06063)the Natural Science Foundation for Distinguished Young Scholars of Shandong Province, China(No.2008JQB01028)
文摘Phase separations have been studied for graded-indium content In_xGa_(1-x)N/GaN multiple quantum wells(MQWs) with different indium contents by means of photoluminescence(PL),cathodeluminescence(CL) and time-resolved PL(TRPL) techniques.Besides the main emission peaks,all samples show another 2 peaks at the high and low energy parts of the main peaks in PL when excited at 10 K.CL images show a clear contrast for 3 samples,which indicates an increasing phase separation with increasing indium content.TRPL spectra at 15 K of the main emissions show an increasing delay of rising time with indium content,which means a carrier transferring from low indium content structures to high indium content structures.
文摘Objective: To investigate the level of acute phase proteins (APP)-synthesized in hepatocytes in pathogenic process of multiple organ dysfunction syndrome (MODS) and the effect of Dachengqi Decoction (DCQD) on it. Methods: The levels of C-reactive protein (CRP),α1-acid glycoprotein (AAG), α1-antitrypsin total (α1AT), α2-macroglobulin (α2-MG), ceruloplasmine (CP), hepatoglobin (HP) and transferrin (TF) synthesis were determined in 32 cases of MODS patients and rat models of MODS induced by acute infective peritonitis and mesenterial artery ischemia-reperfusion.Results: The serum APP level in MODS patients was increased and higher than that in the control group (P < 0. 01 ). After 3 days of DCQD treatment it reduced significantly (P <0. 05). Serum APP level in MODS model was also increased significantly, and after 3 days of DCQD treatment, it reduced significantly (P < 0. 05). The APP secreting level of rat hepatocytes cultured in vitro raised after stimulated and activated by lipopolysacchride, which was reduced after cultured with rabbits serum containing different concentration of effective ingredients of DCQD. The APP inhibiting effect of DCQD was dose dependent. Conclusion: Purgation therapy with DCQD could reduce the stimulation of pathogenic factors on hepatocytes, protect tissues and organs from damage caused by excessive inflammatory reaction.Original article on CJIM(Chin) 1998; 18(8): 453
基金This work was supported by the National Natural Science Foundation of China(51803085,51963016,U1801256,51833004).
文摘Recently,the two-dimensional(2D)ruddlesden-popper(RPP)perovskite has been successfully attracting great attention owing to their excellent electronic property and superior ambient stability.But 2D perovskite solar cells(PVSCs)with insulating large cations show a worse performance than three-dimensional(3D)PVSCs in general because of the worse charge transportation.In this work,dimethyl sulfoxide(DMSO)and KI were incorporated simultaneously to produce a synergistic effect on both film quality and orientation of 2D perovskite.With this strategy,a cavity-free 2D perovskite film was formed with vertically oriented crystal,and high quality film was obtained with decreased defects and increased crystallinity.Besides,profitable multiple phases were obtained for better spontaneous carrier separation and transportation.The 2D PVSCs based on(PEA)2(MA)n−1PbnI3n+1(n=5)delivered a higher power conversion efficiency(PCE)of 13.4%.In addition,the perovskite with KI and DMSO contained more stable low-dimension phase at the bottom of perovskite film,which could act as a barrier to prevent moisture from further eroding internal perovskites.The optimized 2D PVSCs remained 90%of the PCE after being exposed in air(50%–60%humidity,room temperature)with a continuous illumination for 300 h.