The relationship among heating rate, mechanical properties, microstructure and texture of Al-Mg-Si-Cu alloy during solution treatment was investigated through tensile test, scanning electron microscope, X-ray diffract...The relationship among heating rate, mechanical properties, microstructure and texture of Al-Mg-Si-Cu alloy during solution treatment was investigated through tensile test, scanning electron microscope, X-ray diffractometer and EBSD technology. The experimental results reveal that there is a non-monotonic relationship among solution heating rate, mechanical properties, microstructure and texture. As the solution heating rate increases, the strength variations are dependent on the tensile direction;work hardening exponent n decreases first, and then increases;plastic strain ratio r increases first, and then decreases, and finally increases. The final microstructure and texture are also affected by heating rate. As heating rate increases, the microstructure transforms from elongated grain structure to equiaxed grain structure, and the average grain size decreases first, and then increases, and decreases finally. Although the texture components including CubeND{001}<310> and P{011}<122> orientations almost have no change with the increase of heating rate, the texture intensity and volume fraction decrease first, and then increase, and finally decrease. Both microstructure and texture evolutions are weakly affected by heating rate. Improving heating rate is not always favorable for the development of fine equiaxed grain structure, weak texture and high average r value, which may be related to the recrystallization behavior.展开更多
Various cooling scenarios(water,oil,air and furnace)were employed to study the impacts of the solution cooling rate(SCR)on the microstructure and creep behavior of a novel single-crystal(SX)superalloy.The results show...Various cooling scenarios(water,oil,air and furnace)were employed to study the impacts of the solution cooling rate(SCR)on the microstructure and creep behavior of a novel single-crystal(SX)superalloy.The results showed that the cubic degree and size of theγphases were inversely proportional to the SCR.The creep life first increased and then dropped dramatically with a reduction in the SCR.The creep life of the sample cooled with air cooling(AC)was the highest,up to 144.90 h at 800℃/750 MPa and160.15 h at 1100℃/137 MPa.During creep at 800℃/750 MPa,the improved creep life of the AC sample was mainly attributed to the fine cubicγphases,which decreased the rate ofγ-phase coarsening and favoured plastic deformation by promoting the active movement of dislocations.The AC helped theγphases become rich in Al,Ti and Ta while depleted in Co and Cr,which enhanced its stacking fault energy,thus promoting the formation of dislocation locks.Meanwhile,the largest negative lattice misfit caused by AC induced denserγ/γinterface dislocation networks at 1100℃/137 MPa,which efficiently reduced the minimum creep rate.The calculated average dislocation spacing results indicated that the smallest density of excess dislocations corresponded to the AC sample,proving its greatest creep resistance.Interestingly,the size of the secondaryγphases first decreased and then increased sharply with decreasing SCR during creep at 1100℃/137 MPa,when fine secondaryγphases had a positive role in the blockage of dislocation movement in the matrix.Eventually,the comprehensive SCR effect was explored to provide more guidance in the design of Re-free SX superalloys.展开更多
The coupling effect of nutrient solution EC （electrical conductivity） levels and CR （circulation rate） on the morphology and quality, in hydroponically grown lettuce was assessed. Lettuce was grown at 5 treatments...The coupling effect of nutrient solution EC （electrical conductivity） levels and CR （circulation rate） on the morphology and quality, in hydroponically grown lettuce was assessed. Lettuce was grown at 5 treatments fi＇om High EC ＆ Low CR to Low EC ＆ High CR. The environmental parameters were controlled in a 20 m^2 plant factory during the hydroponic cultivation with the following values： irradiated by blue and red light-emitting diode lighting with PPFD （photosynthetic photon flux density） value of 150 mol·m^-2·s^-1 for 16 hours per day; Temperature was maintained at 22.0 ℃ during the photoperiod and 16.0 ℃ in dark cycle. The results demonstrate that growing lettuce can be adopted using nutrient solution with lower EC levels and higher CR. The results also indicate that the effect of bi-directional coupled EC and CR resulted in expansion of root length but reducing the root biomass. Nitrate content was significantly reduced.展开更多
To evaluate stress corrosion cracking（SCC） mechanism of low alloy ultra-high strength steel 30CrMnSiNi2 A in environment containing NaCl, SCC behavior of the steel in 3.5wt% NaCl solution is investigated by slow str...To evaluate stress corrosion cracking（SCC） mechanism of low alloy ultra-high strength steel 30CrMnSiNi2 A in environment containing NaCl, SCC behavior of the steel in 3.5wt% NaCl solution is investigated by slow strain rate technique（SSRT） with various strain rates and applied potentials, surface analysis technique, and electrochemical measurements. SCC susceptibility of the steel increases rapidly with strain rate decreasing from 1 · 10 5s 1to 5 · 10 7s 1, and becomes stable when strain rate is lower than 5 · 10 7s 1. SCC propagation of the steel in the solution at open circuit potential（OCP） needs sufficient hydrogen which is supplied at a certain strain rate.Fracture surface at OCP has similar characteristics with that at cathodic polarization 1000 mVSCE, which presents characteristic fractography of hydrogen induced cracking（HIC）.All of these indicate that SCC behavior of the steel in the solution at OCP is mainly controlled by HIC rather than anodic dissolution（AD）.展开更多
ZTE Corporation announced on 1 March that its innovative IPTVlowbitrate highdefinition transcoding solution has been nominated for the World＇s Best Component or Enabler Award by the IPTV World Forum. The ZTE solution...ZTE Corporation announced on 1 March that its innovative IPTVlowbitrate highdefinition transcoding solution has been nominated for the World＇s Best Component or Enabler Award by the IPTV World Forum. The ZTE solution is on display at the Mobile World Congress 2012 （MWC 2012） in Barcelona.展开更多
This paper presents anew regularization method for solving operator equations of the first kind; the convergence rate of the regularized solution is improved, as compared with the ordinary Tikhonov regularization.
Mg-8Li-3Al＋xCe alloys（x = 0.5wt%, 1.0wt%, and 1.5wt%） were prepared through a casting route in an electric resistance furnace under a controlled atmosphere. The cast alloys were characterized by X-ray diffraction, ...Mg-8Li-3Al＋xCe alloys（x = 0.5wt%, 1.0wt%, and 1.5wt%） were prepared through a casting route in an electric resistance furnace under a controlled atmosphere. The cast alloys were characterized by X-ray diffraction, optical microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The corrosion behavior of the as-cast Mg-8Li-3Al＋xCe alloys were studied under salt spray tests in 3.5wt% NaC l solution at 35°C, in accordance with standard ASTM B-117, in conjunction with potentiodynamic polarization（PDP） tests. The results show that the addition of Ce to Mg-8Li-3Al（LA83） alloy results in the formation of Al_2Ce intermetallic phase, refines both the α-Mg phase and the Mg_（17）Al_（12） intermetallic phase, and then increases the microhardness of the alloys. The results of PDP and salt spray tests reveal that an increase in Ce content to 1.5wt% decreases the corrosion rate. The best corrosion resistance is observed for the LA83 alloy sample with 1.0wt% Ce.展开更多
Finding alternative local sources of plant nutrients is a practical, low-cost, and long-term strategy. In this study, laboratory column experiments were conducted in a completely randomized design to evaluate the feas...Finding alternative local sources of plant nutrients is a practical, low-cost, and long-term strategy. In this study, laboratory column experiments were conducted in a completely randomized design to evaluate the feasibility of using phosphate rock and dolostone as fertilizers or acid-neutralizing agents for application in tropical acid soils. The dissolution rates of different particle-size fractions(0.063–0.25, 0.25–0.5, and 0.5–2 mm) of both rocks were studied by citric acid solution at p H 4 and 2 and water, with extraction times of 1, 3, 5, 7, 12, 24, 72, 144, 240, and 360 h. The results showed that the dissolution of both rocks depended on the particle size,leaching solution, and extraction time. The dissolution rate of rock-forming minerals increased as the specific surface area increased,corresponding to a decrease in particle size. In all cases, the release kinetics was characterized by two phases: 1) a first stage of rapid release that lasted 24 h and would ensure short-term nutrient release, and 2) a second stage of slow release after 24 h, representing the long-term nutrient release efficiency. Both rocks were suitable as slow-release fertilizers in strongly acid soils and would ensure the replenishment of P, Ca, and Mg. A combination of fine and medium particle-size fractions should be used to ensure high nutrient-release efficiency. Much work could remain to determine the overall impact of considerable amounts of fresh rocks in soils.展开更多
The temperature changes at the rim,1/2 radius,and bore of the turbine disk during the solution treatment were measured.Based on the measured temperature data,solution treatment experiments with different cooling rates...The temperature changes at the rim,1/2 radius,and bore of the turbine disk during the solution treatment were measured.Based on the measured temperature data,solution treatment experiments with different cooling rates(14,51,and 93℃/min)were performed,and the solution temperatures were 1120 and 1080℃.At all three cooling rates,the multimodal size distribution of γ' precipitates was detected,and the size of γ' precipitates is inversely related to the cooling rate.Only the secondary and tertiary γ' precipitates were found at a solution temperature of 1120℃,and the secondary γ' precipitates progressed from spherical(93 and 51℃/min)to flower-like(14℃/min)shape,with the flower-like γ' precipitates regulated by aggregation.At a solution temperature of 1080℃,the γ' precipitates evolve from cuboids(93 and 51℃/min)to irregular shapes(14℃/min).Irregular γ' precipitates are affected by the lattice mismatch between the matrix and the γ' precipitates.展开更多
The aim of this work is to investigate the dependence of Zn S thin films structural and optical properties with the solution flow rate during the deposition using an ultrasonic spray method. The solution flow rate ran...The aim of this work is to investigate the dependence of Zn S thin films structural and optical properties with the solution flow rate during the deposition using an ultrasonic spray method. The solution flow rate ranged from 10 to 50 m L/h and the substrate temperature was maintained at 450 °C. The effect of the solution flow rate on the properties of Zn S thin films was investigated by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, optical transmittance spectroscopy（UV–V） and the four-point method. The X-ray diffraction analysis showed that the deposited material was pure zinc sulphide, it has a cubic sphalerite structure with preferential orientation along the（111） direction. The grain size values were calculated and found to be between 38 to 82 nm.SEM analysis revealed that the deposited thin films have good adherence to the substrate surfaces, are homogeneous and have high density. The average transmission of all films is up more than 65% in the range wavelength from 200 to 1100 nm and their band gap energy values were found between 3.5–3.92 e V. The obtained film thickness varies from 390 to 1040 nm. Moreover, the electric resistivity of the deposited films increases with the increasing of the solution flow rate between 3.51 × 10^5 and 11 × 10^5 Ω·cm.展开更多
We report results of a large computational ＇alloy by design＇ study, in which the ＇chemical composition-mechanical strength＇ space is explored for austenitic, ferritic and martensitic creep resistant steels. The ap...We report results of a large computational ＇alloy by design＇ study, in which the ＇chemical composition-mechanical strength＇ space is explored for austenitic, ferritic and martensitic creep resistant steels. The approach used allows simultaneously optimization of alloy composition and processing parameters based on the integration of thermodynamic, thermo-kinetics and a genetic algorithm optimization route. The nature of the optimisation depends on both the intended matrix（ferritic, martensitic or austenitic） and the desired precipitation family. The models are validated by analysing reported strengths of existing steels. All newly designed alloys are predicted to outperform existing high end reference grades.展开更多
Understanding the ongoing speleogenic processes that produce sinkholes and control the vital drinking water supplies of Florida and much else of the world is necessary research. This article （and the associated poste...Understanding the ongoing speleogenic processes that produce sinkholes and control the vital drinking water supplies of Florida and much else of the world is necessary research. This article （and the associated poster presentation） discusses theoretical processes that may act in addition to mass dissolution kinetics in producing voids, conduits and caves in autogenic karst landforms. Possible theoretical factors that affect these speleogenic processes are： microscopic mixing corrosion （low constant flow, low constant flow against current, temperature-induced mixing corrosion, and pressure-induced mixing corrosion in karst matrix）, random dissolution models, simulation of gravity-induced microscopic breakdown, and storm surge effects. Finally, a theoretical model is discussed that unifies these various microscopic processes into a macro-scale process, called internal pressure sculpting. Computer models were designed to illustrate these theoretical processes： Non-calibrated computer models simulating each process discussed in this paper are presented for illustration, as well as the preliminary results of calibrated models depicting random dissolution, mechanical breakdown, and storm surge effects. The theoretical processes discussed and simulated may have major effects on cave morphology. Computer simulations appear to accurately portray the shape and form of some cave features with dissolutional morphologies. Theoretical discussion concludes with a general discussion of possible improvements to the presented models as well as the ability to generalize theoretical processes to hypogenic, halogenic, and autogenic speleogenesis.展开更多
In this paper, a simplified iterative regnlarization method was used to solve the operator equations of the first kind involving semi-positive definite operators, the convergence rates of regularized solutions were ob...In this paper, a simplified iterative regnlarization method was used to solve the operator equations of the first kind involving semi-positive definite operators, the convergence rates of regularized solutions were obtained and a posteriori parametr choice strategy was given.展开更多
基金The authors are grateful for the financial supports from the Science Challenge Project(TZ2018001)the State Key Laboratory of Advanced Metals and Materials University of Science and Technology Beijing,China(2019-Z02)+3 种基金the National Natural Science Foundation of China(52075272)the Key Laboratory of Impact and Safety Engineering,Ministry of Education,Ningbo University,China(CJ201912)the Ningbo Natural Science Foundation,China(2018A610174)the K.C.Wong Magna Fund from Ningbo University,China.
文摘The relationship among heating rate, mechanical properties, microstructure and texture of Al-Mg-Si-Cu alloy during solution treatment was investigated through tensile test, scanning electron microscope, X-ray diffractometer and EBSD technology. The experimental results reveal that there is a non-monotonic relationship among solution heating rate, mechanical properties, microstructure and texture. As the solution heating rate increases, the strength variations are dependent on the tensile direction;work hardening exponent n decreases first, and then increases;plastic strain ratio r increases first, and then decreases, and finally increases. The final microstructure and texture are also affected by heating rate. As heating rate increases, the microstructure transforms from elongated grain structure to equiaxed grain structure, and the average grain size decreases first, and then increases, and decreases finally. Although the texture components including CubeND{001}<310> and P{011}<122> orientations almost have no change with the increase of heating rate, the texture intensity and volume fraction decrease first, and then increase, and finally decrease. Both microstructure and texture evolutions are weakly affected by heating rate. Improving heating rate is not always favorable for the development of fine equiaxed grain structure, weak texture and high average r value, which may be related to the recrystallization behavior.
基金financially supported by the National Key R&D Program of China(No.2017YFA0700704)the National Science and Technology Major Project(No.2017-VI-0002-0072)the Youth Innovation Promotion Association,Chinese Academy of Sciences and Innovation Academy for Light-duty Gas Turbine,Chinese Academy of Sciences(No.CXYJJ20-MS-03)。
文摘Various cooling scenarios(water,oil,air and furnace)were employed to study the impacts of the solution cooling rate(SCR)on the microstructure and creep behavior of a novel single-crystal(SX)superalloy.The results showed that the cubic degree and size of theγphases were inversely proportional to the SCR.The creep life first increased and then dropped dramatically with a reduction in the SCR.The creep life of the sample cooled with air cooling(AC)was the highest,up to 144.90 h at 800℃/750 MPa and160.15 h at 1100℃/137 MPa.During creep at 800℃/750 MPa,the improved creep life of the AC sample was mainly attributed to the fine cubicγphases,which decreased the rate ofγ-phase coarsening and favoured plastic deformation by promoting the active movement of dislocations.The AC helped theγphases become rich in Al,Ti and Ta while depleted in Co and Cr,which enhanced its stacking fault energy,thus promoting the formation of dislocation locks.Meanwhile,the largest negative lattice misfit caused by AC induced denserγ/γinterface dislocation networks at 1100℃/137 MPa,which efficiently reduced the minimum creep rate.The calculated average dislocation spacing results indicated that the smallest density of excess dislocations corresponded to the AC sample,proving its greatest creep resistance.Interestingly,the size of the secondaryγphases first decreased and then increased sharply with decreasing SCR during creep at 1100℃/137 MPa,when fine secondaryγphases had a positive role in the blockage of dislocation movement in the matrix.Eventually,the comprehensive SCR effect was explored to provide more guidance in the design of Re-free SX superalloys.
文摘The coupling effect of nutrient solution EC （electrical conductivity） levels and CR （circulation rate） on the morphology and quality, in hydroponically grown lettuce was assessed. Lettuce was grown at 5 treatments fi＇om High EC ＆ Low CR to Low EC ＆ High CR. The environmental parameters were controlled in a 20 m^2 plant factory during the hydroponic cultivation with the following values： irradiated by blue and red light-emitting diode lighting with PPFD （photosynthetic photon flux density） value of 150 mol·m^-2·s^-1 for 16 hours per day; Temperature was maintained at 22.0 ℃ during the photoperiod and 16.0 ℃ in dark cycle. The results demonstrate that growing lettuce can be adopted using nutrient solution with lower EC levels and higher CR. The results also indicate that the effect of bi-directional coupled EC and CR resulted in expansion of root length but reducing the root biomass. Nitrate content was significantly reduced.
基金financial support from the National Natural Science Foundation of China (No. 51171011)
文摘To evaluate stress corrosion cracking（SCC） mechanism of low alloy ultra-high strength steel 30CrMnSiNi2 A in environment containing NaCl, SCC behavior of the steel in 3.5wt% NaCl solution is investigated by slow strain rate technique（SSRT） with various strain rates and applied potentials, surface analysis technique, and electrochemical measurements. SCC susceptibility of the steel increases rapidly with strain rate decreasing from 1 · 10 5s 1to 5 · 10 7s 1, and becomes stable when strain rate is lower than 5 · 10 7s 1. SCC propagation of the steel in the solution at open circuit potential（OCP） needs sufficient hydrogen which is supplied at a certain strain rate.Fracture surface at OCP has similar characteristics with that at cathodic polarization 1000 mVSCE, which presents characteristic fractography of hydrogen induced cracking（HIC）.All of these indicate that SCC behavior of the steel in the solution at OCP is mainly controlled by HIC rather than anodic dissolution（AD）.
文摘ZTE Corporation announced on 1 March that its innovative IPTVlowbitrate highdefinition transcoding solution has been nominated for the World＇s Best Component or Enabler Award by the IPTV World Forum. The ZTE solution is on display at the Mobile World Congress 2012 （MWC 2012） in Barcelona.
文摘This paper presents anew regularization method for solving operator equations of the first kind; the convergence rate of the regularized solution is improved, as compared with the ordinary Tikhonov regularization.
文摘Mg-8Li-3Al＋xCe alloys（x = 0.5wt%, 1.0wt%, and 1.5wt%） were prepared through a casting route in an electric resistance furnace under a controlled atmosphere. The cast alloys were characterized by X-ray diffraction, optical microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The corrosion behavior of the as-cast Mg-8Li-3Al＋xCe alloys were studied under salt spray tests in 3.5wt% NaC l solution at 35°C, in accordance with standard ASTM B-117, in conjunction with potentiodynamic polarization（PDP） tests. The results show that the addition of Ce to Mg-8Li-3Al（LA83） alloy results in the formation of Al_2Ce intermetallic phase, refines both the α-Mg phase and the Mg_（17）Al_（12） intermetallic phase, and then increases the microhardness of the alloys. The results of PDP and salt spray tests reveal that an increase in Ce content to 1.5wt% decreases the corrosion rate. The best corrosion resistance is observed for the LA83 alloy sample with 1.0wt% Ce.
基金supported by the "Applied Research and Multi-sectorial Program" (FIAM) (No. 5.2.1) granted by the Italian Cooperation and Development Agency (ICDA) to the Universidade Eduardo Mondlanethe Polytechnic University of Marche, Italy for the PhD scholarship provided to the first author as well as research funding for this work
文摘Finding alternative local sources of plant nutrients is a practical, low-cost, and long-term strategy. In this study, laboratory column experiments were conducted in a completely randomized design to evaluate the feasibility of using phosphate rock and dolostone as fertilizers or acid-neutralizing agents for application in tropical acid soils. The dissolution rates of different particle-size fractions(0.063–0.25, 0.25–0.5, and 0.5–2 mm) of both rocks were studied by citric acid solution at p H 4 and 2 and water, with extraction times of 1, 3, 5, 7, 12, 24, 72, 144, 240, and 360 h. The results showed that the dissolution of both rocks depended on the particle size,leaching solution, and extraction time. The dissolution rate of rock-forming minerals increased as the specific surface area increased,corresponding to a decrease in particle size. In all cases, the release kinetics was characterized by two phases: 1) a first stage of rapid release that lasted 24 h and would ensure short-term nutrient release, and 2) a second stage of slow release after 24 h, representing the long-term nutrient release efficiency. Both rocks were suitable as slow-release fertilizers in strongly acid soils and would ensure the replenishment of P, Ca, and Mg. A combination of fine and medium particle-size fractions should be used to ensure high nutrient-release efficiency. Much work could remain to determine the overall impact of considerable amounts of fresh rocks in soils.
基金supported by the National Science and Technology Major Project(2017-VI-0018-0090).
文摘The temperature changes at the rim,1/2 radius,and bore of the turbine disk during the solution treatment were measured.Based on the measured temperature data,solution treatment experiments with different cooling rates(14,51,and 93℃/min)were performed,and the solution temperatures were 1120 and 1080℃.At all three cooling rates,the multimodal size distribution of γ' precipitates was detected,and the size of γ' precipitates is inversely related to the cooling rate.Only the secondary and tertiary γ' precipitates were found at a solution temperature of 1120℃,and the secondary γ' precipitates progressed from spherical(93 and 51℃/min)to flower-like(14℃/min)shape,with the flower-like γ' precipitates regulated by aggregation.At a solution temperature of 1080℃,the γ' precipitates evolve from cuboids(93 and 51℃/min)to irregular shapes(14℃/min).Irregular γ' precipitates are affected by the lattice mismatch between the matrix and the γ' precipitates.
文摘The aim of this work is to investigate the dependence of Zn S thin films structural and optical properties with the solution flow rate during the deposition using an ultrasonic spray method. The solution flow rate ranged from 10 to 50 m L/h and the substrate temperature was maintained at 450 °C. The effect of the solution flow rate on the properties of Zn S thin films was investigated by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, optical transmittance spectroscopy（UV–V） and the four-point method. The X-ray diffraction analysis showed that the deposited material was pure zinc sulphide, it has a cubic sphalerite structure with preferential orientation along the（111） direction. The grain size values were calculated and found to be between 38 to 82 nm.SEM analysis revealed that the deposited thin films have good adherence to the substrate surfaces, are homogeneous and have high density. The average transmission of all films is up more than 65% in the range wavelength from 200 to 1100 nm and their band gap energy values were found between 3.5–3.92 e V. The obtained film thickness varies from 390 to 1040 nm. Moreover, the electric resistivity of the deposited films increases with the increasing of the solution flow rate between 3.51 × 10^5 and 11 × 10^5 Ω·cm.
基金financial support from the Chinese Scholarship Council(CSC)and internal funding of TU Delft
文摘We report results of a large computational ＇alloy by design＇ study, in which the ＇chemical composition-mechanical strength＇ space is explored for austenitic, ferritic and martensitic creep resistant steels. The approach used allows simultaneously optimization of alloy composition and processing parameters based on the integration of thermodynamic, thermo-kinetics and a genetic algorithm optimization route. The nature of the optimisation depends on both the intended matrix（ferritic, martensitic or austenitic） and the desired precipitation family. The models are validated by analysing reported strengths of existing steels. All newly designed alloys are predicted to outperform existing high end reference grades.
文摘Understanding the ongoing speleogenic processes that produce sinkholes and control the vital drinking water supplies of Florida and much else of the world is necessary research. This article （and the associated poster presentation） discusses theoretical processes that may act in addition to mass dissolution kinetics in producing voids, conduits and caves in autogenic karst landforms. Possible theoretical factors that affect these speleogenic processes are： microscopic mixing corrosion （low constant flow, low constant flow against current, temperature-induced mixing corrosion, and pressure-induced mixing corrosion in karst matrix）, random dissolution models, simulation of gravity-induced microscopic breakdown, and storm surge effects. Finally, a theoretical model is discussed that unifies these various microscopic processes into a macro-scale process, called internal pressure sculpting. Computer models were designed to illustrate these theoretical processes： Non-calibrated computer models simulating each process discussed in this paper are presented for illustration, as well as the preliminary results of calibrated models depicting random dissolution, mechanical breakdown, and storm surge effects. The theoretical processes discussed and simulated may have major effects on cave morphology. Computer simulations appear to accurately portray the shape and form of some cave features with dissolutional morphologies. Theoretical discussion concludes with a general discussion of possible improvements to the presented models as well as the ability to generalize theoretical processes to hypogenic, halogenic, and autogenic speleogenesis.
文摘In this paper, a simplified iterative regnlarization method was used to solve the operator equations of the first kind involving semi-positive definite operators, the convergence rates of regularized solutions were obtained and a posteriori parametr choice strategy was given.
