In this paper, a modified Newton type iterative method is considered for ap- proximately solving ill-posed nonlinear operator equations involving m-accretive mappings in Banach space. Convergence rate of the method is...In this paper, a modified Newton type iterative method is considered for ap- proximately solving ill-posed nonlinear operator equations involving m-accretive mappings in Banach space. Convergence rate of the method is obtained based on an a priori choice of the regularization parameter. Our analysis is not based on the sequential continuity of the normalized duality mapping.展开更多
Matrix effect primarily impacts the accuracy and precision of zircon LA-ICP-MS U-Pb data.This paper describes three types of matrix effect in zircon LA-ICPMS U-Pb dating,i.e.,the element matrix effect,high Ddpa or ura...Matrix effect primarily impacts the accuracy and precision of zircon LA-ICP-MS U-Pb data.This paper describes three types of matrix effect in zircon LA-ICPMS U-Pb dating,i.e.,the element matrix effect,high Ddpa or uranium matrix effect and alpha dose matrix effect,and illustrates the correction of these three effects.In addition,we point out the limitation and possible problems of the existing correction methods.展开更多
Xanthomonas citri pv.citri(Xcc),a gram-negative bacterium,is the causal agent of citrus canker,one of the most devastating diseases threatening the citrus industry worldwide.Understanding the diversity and population ...Xanthomonas citri pv.citri(Xcc),a gram-negative bacterium,is the causal agent of citrus canker,one of the most devastating diseases threatening the citrus industry worldwide.Understanding the diversity and population structure of Xcc is a prerequisite for disease epidemiological monitoring and effective disease management.Recent characterization of the clustered regularly interspaced short palindromic repeats(CRISPR)/cas(CRISPR-associated proteins genes)system with a highly variable repeat number among species provides a new molecular typing method for bacterial genetic analysis.In this study,we performed systematic in silico analyses of 28 Xcc genomes and identified a credible CRISPR/cas in Xcc strains.Further analysis of CRISPR polymorphisms(repeat number and spacer types)in 129 Xcc A strains collected from six provinces in China identified 15 types of CRISPR arrays with 25 spacers.Phylogenetic analysis of Xcc strains based on the CRISPR locus produced a more reliable and accurate typing result compared to the commonly used loci.In addition,seven associated cas genes—cas1,cas2,cas3,cas4,cas5,cas7(csd2),and cas8(csd1)—were found located adjacent to the CRISPR array.BLAST results showed>99%similarity of seven cas genes among Xcc strains.Homology analysis of spacer sequences showed that six spacers had possible phage/prophage origin.The characterization of the CRISPR/cas system among Xcc strains provided an updated strain typing method for Xcc diversity analysis and yielded a panoramic view of CRISPR evolution for further studies of Xcc-phage interactions.展开更多
Oxygen reduction reaction(ORR)is the heart of many new energy conversions and storage devices,such as metal-air batteries and fuel cells.However,ORR is currently facing the dilemma of sluggish intrinsic kinetics and t...Oxygen reduction reaction(ORR)is the heart of many new energy conversions and storage devices,such as metal-air batteries and fuel cells.However,ORR is currently facing the dilemma of sluggish intrinsic kinetics and the noble electrocatalysts of high price and low reserves.In this work,isolated Co atoms anchored on defective nitrogen-doped carbon graphene single-atom catalyst(Co-SAC/NC)are synthesized via the proposed movable type printing method.The prepared Co-SAC/NC catalyst demonstrates admirable ORR performance,with a high half-wave potential of 0.884 V in alkaline electrolytes and outstanding durability.In addition,an assembled zinc–air battery with prepared Co-SAC/NC as air-cathode catalyst displays a high-peak power density of 179 mW cm^(-2)and a high-specific capacity(757 mAh g^(-1)).Density functional theory calculations confirm that the true active sites of the prepared catalyst are Co-N_(4)moieties,and further reveal a significantly electronic structure evolution of Co sites in the ORR process,in which the project density of states and local magnetic moment of Co atom varies during its whole reaction process.This work not only paves a new avenue for synthesizing SACs as robust electrocatalysts,but also provides an electronic-level insight into the evolution of the electronic structure of single-atom catalysts.展开更多
In order to provide abundant atomic data for fusion research in the stage of precision physics, a scenario, being a combination of indispensable theoretical calculations and bench-mark experimental measurements, is pr...In order to provide abundant atomic data for fusion research in the stage of precision physics, a scenario, being a combination of indispensable theoretical calculations and bench-mark experimental measurements, is proposed. Such abundant atomic data are compiled mainly by theoretical calculations. Accuracies of such abundant data (i.e., atomic energy levels and cor- responding cross sections) are ascertained only by a finite number of bench-mark experimental measurements based on analytical calculation of scattering matrices.展开更多
This paper studies the two-electron total energy and the energy of the electron-electron interaction by using a variational method of Pekar type on the condition of electric-LO-phonon strong coupling in a parabolic qu...This paper studies the two-electron total energy and the energy of the electron-electron interaction by using a variational method of Pekar type on the condition of electric-LO-phonon strong coupling in a parabolic quantum dot. It considers the following three cases: 1) two electrons are in the ground state; 2) one electron is in the ground state, the other is in the first-excited state; 3) two electrons are in the first-excited state. The relations of the two-electron total energy and the energy of the electron-electron interaction on the Coulomb binding parameter, the electron-LO-phonon coupling constant and the confinement length of the quantum dot are derived in the three cases.展开更多
To improve flood control efficiency and increase urban resilience to flooding,the impacts of forest type change on flood control in the upper reach of the Tingjiang River(URTR) were evaluated by a modified model based...To improve flood control efficiency and increase urban resilience to flooding,the impacts of forest type change on flood control in the upper reach of the Tingjiang River(URTR) were evaluated by a modified model based on the Soil Conservation Service curve number(SCS-CN) method. Parameters of the model were selected and determined according to the comprehensive analysis of model evaluation indexes. The first simulation of forest reconstruction scenario,namely a coniferous forest covering 59.35km^2 is replaced by a broad-leaved forest showed no significant impact on the flood reduction in the URTR. The second simulation was added with 61.75km^2 bamboo forest replaced by broad-leaved forest,the reduction of flood peak discharge and flood volume could be improved significantly. Specifically,flood peak discharge of 10-year return period event was reduced to 7-year event,and the reduction rate of small flood was 21%-28%. Moreover,the flood volume was reduced by 9%-14% and 18%-35% for moderate floods and small floods,respectively. The resultssuggest that the bamboo forest reconstruction is an effective control solution for small to moderate flood in the URTR,the effect of forest conversion on flood volume is increasingly reduced as the rainfall amount increases to more extreme magnitude. Using a hydrological model with scenarios analysis is an effective simulation approach in investigating the relationship between forest type change and flood control. This method would provide reliable support for flood control and disaster mitigation in mountainous cities.展开更多
The cracking behavior of lightweight aggregate concrete(LWAC) was investigated by mechanical analysis, SEM and cracking-resistant test where a shrinkage-restrained ring with a clapboard was used. The relationship betw...The cracking behavior of lightweight aggregate concrete(LWAC) was investigated by mechanical analysis, SEM and cracking-resistant test where a shrinkage-restrained ring with a clapboard was used. The relationship between the ceramsite type and the cracking resistance of LWAC was built up and compared with that of normal-weight coarse aggregate concrete(NWAC). A new method was proposed to evaluate the cracking resistance of concrete, where the concepts of cracking coefficient ζt(t) and the evaluation index Acr(t) were proposed, and the development of micro-cracks and damage accumulation were recognized. For the concrete with an ascending cracking coefficient curve, the larger Acr(t) is, the lower cracking resistance of concrete is. For the concrete with a descending cracking coefficient curve, the larger Acr(t) is, the stronger the cracking resistance of concrete is. The evaluation results show that in the case of that all the three types of coarse aggregates in concrete are pre-soaked for 24 h, NWAC has the lowest cracking resistance, followed by the LWAC with lower water absorption capacity ceramsite and the LWAC with higher water absorption capacity ceramsite has the strongest cracking resistance. The proposed method has obvious advantages over the cracking age method, because it can evaluate the cracking behavior of concrete even if the concrete has not an observable crack.展开更多
Objective: This study sought to investigate the content of the prescription rights and the prescription types of midwives under certain circumstances in China. Methods: The Delphi method was used to consult 18 nursi...Objective: This study sought to investigate the content of the prescription rights and the prescription types of midwives under certain circumstances in China. Methods: The Delphi method was used to consult 18 nursing experts and 14 medical experts, A total of 30 experts finished the consulting. The reliability of the expert opinions was analyzed to determine the specific situations in which midwives may write prescriptions, the content of the prescription rights and the prescription types. Results: In six specific circumstances (uterine contraction fatigue, uterine contractions that are too strong, postpartum hemorrhage, premature rupture of the membranes, normal delivery and neonatal asphyxia), midwives have the right to prescribe and administer medication, including 20 drugs and 13 auxiliary examinations. Of these drugs and examinations, 51.5% of the drugs and adjuvant examination prescriptions tend to be independent prescriptions, 30.3% tend to be protocol prescriptions, and 18.2% are similar to both types. Conclusions: The midwives should be granted some prescription rights to enhance their autonomy and the professionalism of midwifery.展开更多
An inverse problem for identification of the coefficient in heat-conduction equation is considered. After reducing the problem to a nonlinear ill-posed operator equation, Newton type iterative methods are considered. ...An inverse problem for identification of the coefficient in heat-conduction equation is considered. After reducing the problem to a nonlinear ill-posed operator equation, Newton type iterative methods are considered. The implicit iterative method is applied to the linearized Newton equation, and the key step in the process is that a new reasonable a posteriori stopping rule for the inner iteration is presented. Numerical experiments for the new method as well as for Tikhonov method and Bakushikskii method are given, and these results show the obvious advantages of the new method over the other ones.展开更多
-Considering both the seabed foundation and wave, an analytic model of 'J' type is proposed for offshore pipeline-laying. The governing differential equation is also obtained for the pipeline on the seabed and...-Considering both the seabed foundation and wave, an analytic model of 'J' type is proposed for offshore pipeline-laying. The governing differential equation is also obtained for the pipeline on the seabed and for the suspension sections. By utilizing weighted- residual method and dual iteration technique, an approximate solution is obtained, too. In the end, calculation examples are given for analyzing the changeable relationship among the major parameters.展开更多
OBJECTIVE: To describe a case of Ehlers-Danlos syndrome type IV and its pedigree in China. METHODS: Clinical materials of a case of Ehlers-Danlos syndrome type IV and a pedigree of 6 members within 4 generations were ...OBJECTIVE: To describe a case of Ehlers-Danlos syndrome type IV and its pedigree in China. METHODS: Clinical materials of a case of Ehlers-Danlos syndrome type IV and a pedigree of 6 members within 4 generations were analyzed. Dilated internal jugular vein in the proband was removed by operation. The diagnosis, surgical treatment, and postoperative complications were retrospectively reviewed. RESULTS: Vessels of the proband in the pedigree were crisp and easily lacinated during the procedure of removing his internal jugular vein. Repeating postoperative hematomas were found though complete stanching was achieved during the operation. The patient was successfully recovered by promptly debridgement and needle sucking. The other 5 members of the pedigree all had the triads of Ehlers-Danlos syndrome. CONCLUSIONS: Though it was of extremely low morbidity rate, the high mortality rate and complication of Ehlers-Danlos syndrome deserve great attention during surgical management, especially in patients with Ehlers-Danlos syndrome type IV. Surgeons should be aware of the ponderance of its complications and combined diseases to avoid fatal intraoperative vascular lascination and incontrollable hemorrhage.展开更多
It is difficult to compute far-field waves in a relative large area by using one wave generation model when a large calculation domain is needed because of large dimensions of the waterway and long distance of the req...It is difficult to compute far-field waves in a relative large area by using one wave generation model when a large calculation domain is needed because of large dimensions of the waterway and long distance of the required computing points. Variation of waterway bathymetry and nonlinearity in the far field cannot be included in a ship fixed process either. A coupled method combining a wave generation model and wave propagation model is then used in this paper to simulate the wash waves generated by the passing ship. A NURBS-based higher order panel method is adopted as the stationary wave generation model; a wave spectrum method and Boussinesq-type equation wave model are used as the wave propagation model for the constant water depth condition and variable water depth condition, respectively. The waves calculated by the NURBS-based higher order panel method in the near field are used as the input for the wave spectrum method and the Boussinesq-type equation wave model to obtain the far-field waves. With this approach it is possible to simulate the ship wash waves including the effects of water depth and waterway bathymetry. Parts of the calculated results are validated experimentally, and the agreement is demonstrated. The effects of ship wash waves on the moored ship are discussed by using a diffraction theory method. The results indicate that the prediction of the ship induced waves by coupling models is feasible.展开更多
Japan is facing a demographic challenge of a falling birthrate coupled with an aging society that is already adversely affecting the economy. The situation is only expected to worsen as the working-age population cont...Japan is facing a demographic challenge of a falling birthrate coupled with an aging society that is already adversely affecting the economy. The situation is only expected to worsen as the working-age population continues to decrease. Well aware of this situation, businesses and offices are seeking ways to enhance the intellectual productivity of their workers. This paper explores environmental elements of work spaces that might stimulate intellectual activity. Using a CAD (AutoCAD) miniature garden program, subjects were asked to design a project room that is optimized for creative work using a certain number of elements--11 types of walls, 14 types of floors, 4 types of scenery, 3 types of furniture and 3 types of plantings--but the subjects were free to position and arrange these elements any way they want. The subjects were then interviewed using the evaluation grid method. Based on the results, we created an evaluation structure diagram by analyzing key words and phrases emphasized by subjects in the interviews. The overall evaluation structure represents a summary overview of all 30 subjects who participated in the experiment. This approach captures all the key elements of the office environment that might be used to stimulate intellectual activity of employees.展开更多
This paper presents a class of methods with high order, good stability, and complete parallelism.This paper first puts the conception of free parameter with which we can choose some parameters in these methods to make...This paper presents a class of methods with high order, good stability, and complete parallelism.This paper first puts the conception of free parameter with which we can choose some parameters in these methods to make these methods more useable. For several cases, we give concrete formulas and obtain numerical results for several methods. Numerical experiments show that these methods are efficient in solving stiff ODEs with high dimension.展开更多
To study the influence of an anisotropic parabolic potential (APP) on the properties of a quantum dot (QD) qubit, we obtain the eigenenergies and eigenfunctions of the ground and first excited state of an electron...To study the influence of an anisotropic parabolic potential (APP) on the properties of a quantum dot (QD) qubit, we obtain the eigenenergies and eigenfunctions of the ground and first excited state of an electron, which is strongly coupled to the bulk longitudinal optical (LO) phonons, in a QD under the influence of an APP by the celebrated Lee-Low-Pines (LLP) unitary transformation and the Pekar type variational (PTV) methods. Then, this kind of two-level quantum system can be excogitated to constitute a single qubit. When the electron locates at the superposition state of its related eigenfunctions, we get the time evolution of the electron's probability density. Finally, the influence of an APP on the QD qubit is investigated. The numerical calculations indicate that the probability density will oscillate periodically and it is a decreasing function of the effective confinement lengths of the APP in different directions. Whereas its oscillatory period is an increasing one and will diminish with enhancing the electron-phonon (EP) coupling strength.展开更多
To solve the problem of inaccurate boundary identification and to eliminate the spurious pressure oscillation in the previously developed immersed smoothed point interpolation method(IS-PIM),a new sharp-interface IS-P...To solve the problem of inaccurate boundary identification and to eliminate the spurious pressure oscillation in the previously developed immersed smoothed point interpolation method(IS-PIM),a new sharp-interface IS-PIM combining mass conservation algorithm,called Sharp-ISPIM-Mass,is proposed in this work.Based on the so called sharp-interface method,the technique of quadratic local velocity reconstruction has been developed by combining with the mass conservation algorithm,which enables the present method improve the accuracy of the velocity field and satisfy the mass conservation condition near the boundary field.So the proposed method would not encounter the problem of spurious mass flux.In addition,a new form of FSI force evaluation considering pressure and viscous force to perform a whole function from the fluid domain to fictitious fluid domain is introduced,which makes the present method obtain more accurate results of FSI force than the original one.Through the numerical studies of a number of benchmark examples,the performance of the Sharp-ISPIM-Mass has been examined and illustrated.展开更多
Aimed at the problem of short life of mixing head in KR mechanical mixing method for desulfurization of hot metal,a new type of mixing stir was proposed.CFD theory was used to simulate the characteristics of the fluid...Aimed at the problem of short life of mixing head in KR mechanical mixing method for desulfurization of hot metal,a new type of mixing stir was proposed.CFD theory was used to simulate the characteristics of the fluid flow for the new type of stirring vessel of water model for KR mechanical desulfurization.Flow characteristics and structures of the flow field were investigated and compared with the traditional cross-flow type.The results show that the new type of impeller can not only improve the defects of the flow caused by stir structure of the traditional type,but also reduce the separation of mixing zone in the stirred tank and make the flow field more uniform to make the desulfurization more fully, thus shortening the mixing time,and improving the life of mixing head.Numerical simulation method has been proven to be sound by comparing with the experimental ones.展开更多
In this paper, a split step ABCD matrix method is suggested to investigate Gaussian beam propagation in a Kerr type metamaterial medium. This method is based on dividing the medium interval into subsequent steps.Meanw...In this paper, a split step ABCD matrix method is suggested to investigate Gaussian beam propagation in a Kerr type metamaterial medium. This method is based on dividing the medium interval into subsequent steps.Meanwhile, Gaussian beam profile in every step is obtained by finding the ABCD matrix of that particular step, and is used to find the ABCD matrix of the next step. Results of the suggested matrix method have been compared with the results of numerical split-step Fourier method for a Kerr medium, which indicates a good agreement. Then, we use the ABCD matrix to investigate Gaussian beams propagation in a Kerr type metamaterial, which is also in agreement with pervious results by other methods.展开更多
文摘In this paper, a modified Newton type iterative method is considered for ap- proximately solving ill-posed nonlinear operator equations involving m-accretive mappings in Banach space. Convergence rate of the method is obtained based on an a priori choice of the regularization parameter. Our analysis is not based on the sequential continuity of the normalized duality mapping.
文摘Matrix effect primarily impacts the accuracy and precision of zircon LA-ICP-MS U-Pb data.This paper describes three types of matrix effect in zircon LA-ICPMS U-Pb dating,i.e.,the element matrix effect,high Ddpa or uranium matrix effect and alpha dose matrix effect,and illustrates the correction of these three effects.In addition,we point out the limitation and possible problems of the existing correction methods.
基金supported by Chinese Modern Agricultural Technology Systems (Grant No.CARS-26)。
文摘Xanthomonas citri pv.citri(Xcc),a gram-negative bacterium,is the causal agent of citrus canker,one of the most devastating diseases threatening the citrus industry worldwide.Understanding the diversity and population structure of Xcc is a prerequisite for disease epidemiological monitoring and effective disease management.Recent characterization of the clustered regularly interspaced short palindromic repeats(CRISPR)/cas(CRISPR-associated proteins genes)system with a highly variable repeat number among species provides a new molecular typing method for bacterial genetic analysis.In this study,we performed systematic in silico analyses of 28 Xcc genomes and identified a credible CRISPR/cas in Xcc strains.Further analysis of CRISPR polymorphisms(repeat number and spacer types)in 129 Xcc A strains collected from six provinces in China identified 15 types of CRISPR arrays with 25 spacers.Phylogenetic analysis of Xcc strains based on the CRISPR locus produced a more reliable and accurate typing result compared to the commonly used loci.In addition,seven associated cas genes—cas1,cas2,cas3,cas4,cas5,cas7(csd2),and cas8(csd1)—were found located adjacent to the CRISPR array.BLAST results showed>99%similarity of seven cas genes among Xcc strains.Homology analysis of spacer sequences showed that six spacers had possible phage/prophage origin.The characterization of the CRISPR/cas system among Xcc strains provided an updated strain typing method for Xcc diversity analysis and yielded a panoramic view of CRISPR evolution for further studies of Xcc-phage interactions.
基金supported by the Hainan Province Science and Technology Special Fund(ZDYF2020037,2020207)the National Natural Science Foundation of China(21805104,22109034,22109035,52164028,62105083),the Postdoctoral Science Foundation of Hainan Province(RZ2100007123)the Start-up Research Foundation of Hainan University(KYQD(ZR)-20008,20082,20083,20084,21065,21124,21125).
文摘Oxygen reduction reaction(ORR)is the heart of many new energy conversions and storage devices,such as metal-air batteries and fuel cells.However,ORR is currently facing the dilemma of sluggish intrinsic kinetics and the noble electrocatalysts of high price and low reserves.In this work,isolated Co atoms anchored on defective nitrogen-doped carbon graphene single-atom catalyst(Co-SAC/NC)are synthesized via the proposed movable type printing method.The prepared Co-SAC/NC catalyst demonstrates admirable ORR performance,with a high half-wave potential of 0.884 V in alkaline electrolytes and outstanding durability.In addition,an assembled zinc–air battery with prepared Co-SAC/NC as air-cathode catalyst displays a high-peak power density of 179 mW cm^(-2)and a high-specific capacity(757 mAh g^(-1)).Density functional theory calculations confirm that the true active sites of the prepared catalyst are Co-N_(4)moieties,and further reveal a significantly electronic structure evolution of Co sites in the ORR process,in which the project density of states and local magnetic moment of Co atom varies during its whole reaction process.This work not only paves a new avenue for synthesizing SACs as robust electrocatalysts,but also provides an electronic-level insight into the evolution of the electronic structure of single-atom catalysts.
基金supported by Ministry of Science and Technology and Ministry of Education of Chinathe Key grant Project of Chinese Ministry of Education (No.306020)+2 种基金National Natural Science Foundation of China (Nos. 10734040, 10905040)the National High-Tech ICF Committee in China and the Yin-He Super-computer Center, Institute of Applied Physics and Mathematics, Beijing, ChinaNational Basic Research Program of China (No.2006CB921468)
文摘In order to provide abundant atomic data for fusion research in the stage of precision physics, a scenario, being a combination of indispensable theoretical calculations and bench-mark experimental measurements, is proposed. Such abundant atomic data are compiled mainly by theoretical calculations. Accuracies of such abundant data (i.e., atomic energy levels and cor- responding cross sections) are ascertained only by a finite number of bench-mark experimental measurements based on analytical calculation of scattering matrices.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10747002)Inner Mongolia Universities Science Research Project (Grant No. NJzc08158)
文摘This paper studies the two-electron total energy and the energy of the electron-electron interaction by using a variational method of Pekar type on the condition of electric-LO-phonon strong coupling in a parabolic quantum dot. It considers the following three cases: 1) two electrons are in the ground state; 2) one electron is in the ground state, the other is in the first-excited state; 3) two electrons are in the first-excited state. The relations of the two-electron total energy and the energy of the electron-electron interaction on the Coulomb binding parameter, the electron-LO-phonon coupling constant and the confinement length of the quantum dot are derived in the three cases.
基金funded by the National Natural Science Foundation of China (Grants No.51278239)
文摘To improve flood control efficiency and increase urban resilience to flooding,the impacts of forest type change on flood control in the upper reach of the Tingjiang River(URTR) were evaluated by a modified model based on the Soil Conservation Service curve number(SCS-CN) method. Parameters of the model were selected and determined according to the comprehensive analysis of model evaluation indexes. The first simulation of forest reconstruction scenario,namely a coniferous forest covering 59.35km^2 is replaced by a broad-leaved forest showed no significant impact on the flood reduction in the URTR. The second simulation was added with 61.75km^2 bamboo forest replaced by broad-leaved forest,the reduction of flood peak discharge and flood volume could be improved significantly. Specifically,flood peak discharge of 10-year return period event was reduced to 7-year event,and the reduction rate of small flood was 21%-28%. Moreover,the flood volume was reduced by 9%-14% and 18%-35% for moderate floods and small floods,respectively. The resultssuggest that the bamboo forest reconstruction is an effective control solution for small to moderate flood in the URTR,the effect of forest conversion on flood volume is increasingly reduced as the rainfall amount increases to more extreme magnitude. Using a hydrological model with scenarios analysis is an effective simulation approach in investigating the relationship between forest type change and flood control. This method would provide reliable support for flood control and disaster mitigation in mountainous cities.
基金Project(51078090)supported by the National Natural Science Foundation of China
文摘The cracking behavior of lightweight aggregate concrete(LWAC) was investigated by mechanical analysis, SEM and cracking-resistant test where a shrinkage-restrained ring with a clapboard was used. The relationship between the ceramsite type and the cracking resistance of LWAC was built up and compared with that of normal-weight coarse aggregate concrete(NWAC). A new method was proposed to evaluate the cracking resistance of concrete, where the concepts of cracking coefficient ζt(t) and the evaluation index Acr(t) were proposed, and the development of micro-cracks and damage accumulation were recognized. For the concrete with an ascending cracking coefficient curve, the larger Acr(t) is, the lower cracking resistance of concrete is. For the concrete with a descending cracking coefficient curve, the larger Acr(t) is, the stronger the cracking resistance of concrete is. The evaluation results show that in the case of that all the three types of coarse aggregates in concrete are pre-soaked for 24 h, NWAC has the lowest cracking resistance, followed by the LWAC with lower water absorption capacity ceramsite and the LWAC with higher water absorption capacity ceramsite has the strongest cracking resistance. The proposed method has obvious advantages over the cracking age method, because it can evaluate the cracking behavior of concrete even if the concrete has not an observable crack.
文摘Objective: This study sought to investigate the content of the prescription rights and the prescription types of midwives under certain circumstances in China. Methods: The Delphi method was used to consult 18 nursing experts and 14 medical experts, A total of 30 experts finished the consulting. The reliability of the expert opinions was analyzed to determine the specific situations in which midwives may write prescriptions, the content of the prescription rights and the prescription types. Results: In six specific circumstances (uterine contraction fatigue, uterine contractions that are too strong, postpartum hemorrhage, premature rupture of the membranes, normal delivery and neonatal asphyxia), midwives have the right to prescribe and administer medication, including 20 drugs and 13 auxiliary examinations. Of these drugs and examinations, 51.5% of the drugs and adjuvant examination prescriptions tend to be independent prescriptions, 30.3% tend to be protocol prescriptions, and 18.2% are similar to both types. Conclusions: The midwives should be granted some prescription rights to enhance their autonomy and the professionalism of midwifery.
文摘An inverse problem for identification of the coefficient in heat-conduction equation is considered. After reducing the problem to a nonlinear ill-posed operator equation, Newton type iterative methods are considered. The implicit iterative method is applied to the linearized Newton equation, and the key step in the process is that a new reasonable a posteriori stopping rule for the inner iteration is presented. Numerical experiments for the new method as well as for Tikhonov method and Bakushikskii method are given, and these results show the obvious advantages of the new method over the other ones.
文摘-Considering both the seabed foundation and wave, an analytic model of 'J' type is proposed for offshore pipeline-laying. The governing differential equation is also obtained for the pipeline on the seabed and for the suspension sections. By utilizing weighted- residual method and dual iteration technique, an approximate solution is obtained, too. In the end, calculation examples are given for analyzing the changeable relationship among the major parameters.
文摘OBJECTIVE: To describe a case of Ehlers-Danlos syndrome type IV and its pedigree in China. METHODS: Clinical materials of a case of Ehlers-Danlos syndrome type IV and a pedigree of 6 members within 4 generations were analyzed. Dilated internal jugular vein in the proband was removed by operation. The diagnosis, surgical treatment, and postoperative complications were retrospectively reviewed. RESULTS: Vessels of the proband in the pedigree were crisp and easily lacinated during the procedure of removing his internal jugular vein. Repeating postoperative hematomas were found though complete stanching was achieved during the operation. The patient was successfully recovered by promptly debridgement and needle sucking. The other 5 members of the pedigree all had the triads of Ehlers-Danlos syndrome. CONCLUSIONS: Though it was of extremely low morbidity rate, the high mortality rate and complication of Ehlers-Danlos syndrome deserve great attention during surgical management, especially in patients with Ehlers-Danlos syndrome type IV. Surgeons should be aware of the ponderance of its complications and combined diseases to avoid fatal intraoperative vascular lascination and incontrollable hemorrhage.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.50879066 and 51409201)the Research Fund for the Doctoral Program of Higher Education of China(Grant No.200804970009)
文摘It is difficult to compute far-field waves in a relative large area by using one wave generation model when a large calculation domain is needed because of large dimensions of the waterway and long distance of the required computing points. Variation of waterway bathymetry and nonlinearity in the far field cannot be included in a ship fixed process either. A coupled method combining a wave generation model and wave propagation model is then used in this paper to simulate the wash waves generated by the passing ship. A NURBS-based higher order panel method is adopted as the stationary wave generation model; a wave spectrum method and Boussinesq-type equation wave model are used as the wave propagation model for the constant water depth condition and variable water depth condition, respectively. The waves calculated by the NURBS-based higher order panel method in the near field are used as the input for the wave spectrum method and the Boussinesq-type equation wave model to obtain the far-field waves. With this approach it is possible to simulate the ship wash waves including the effects of water depth and waterway bathymetry. Parts of the calculated results are validated experimentally, and the agreement is demonstrated. The effects of ship wash waves on the moored ship are discussed by using a diffraction theory method. The results indicate that the prediction of the ship induced waves by coupling models is feasible.
文摘Japan is facing a demographic challenge of a falling birthrate coupled with an aging society that is already adversely affecting the economy. The situation is only expected to worsen as the working-age population continues to decrease. Well aware of this situation, businesses and offices are seeking ways to enhance the intellectual productivity of their workers. This paper explores environmental elements of work spaces that might stimulate intellectual activity. Using a CAD (AutoCAD) miniature garden program, subjects were asked to design a project room that is optimized for creative work using a certain number of elements--11 types of walls, 14 types of floors, 4 types of scenery, 3 types of furniture and 3 types of plantings--but the subjects were free to position and arrange these elements any way they want. The subjects were then interviewed using the evaluation grid method. Based on the results, we created an evaluation structure diagram by analyzing key words and phrases emphasized by subjects in the interviews. The overall evaluation structure represents a summary overview of all 30 subjects who participated in the experiment. This approach captures all the key elements of the office environment that might be used to stimulate intellectual activity of employees.
基金Supported by the National Natural Science Foundationof China(No.195 710 4 6 )
文摘This paper presents a class of methods with high order, good stability, and complete parallelism.This paper first puts the conception of free parameter with which we can choose some parameters in these methods to make these methods more useable. For several cases, we give concrete formulas and obtain numerical results for several methods. Numerical experiments show that these methods are efficient in solving stiff ODEs with high dimension.
基金supported by the National Natural Science Foundation of China(No.10964005)
文摘To study the influence of an anisotropic parabolic potential (APP) on the properties of a quantum dot (QD) qubit, we obtain the eigenenergies and eigenfunctions of the ground and first excited state of an electron, which is strongly coupled to the bulk longitudinal optical (LO) phonons, in a QD under the influence of an APP by the celebrated Lee-Low-Pines (LLP) unitary transformation and the Pekar type variational (PTV) methods. Then, this kind of two-level quantum system can be excogitated to constitute a single qubit. When the electron locates at the superposition state of its related eigenfunctions, we get the time evolution of the electron's probability density. Finally, the influence of an APP on the QD qubit is investigated. The numerical calculations indicate that the probability density will oscillate periodically and it is a decreasing function of the effective confinement lengths of the APP in different directions. Whereas its oscillatory period is an increasing one and will diminish with enhancing the electron-phonon (EP) coupling strength.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51639003,51809035)This work was supported by the High-technology ship research project of Ministry of Industry and Information Technology of China(Grant No.2017-614)+3 种基金the Joint Found for Equipment Pre Research and China Shipbuilding Industry Corporation(Grant No.614B042802-28)the Fundamental Research Funds for the Central Universities(Grant No.DUT2017TB05),the China Postdoctoral Science Foundation(Grant No.2018M641693)the Liaoning Revitalization Talents Program(Grant No.XLYC1908027)the Science Foundation of Hunan Province(Grant No.2019JJ50790)and the computation support of the Supercomputing Center of Dalian University of Technology.
文摘To solve the problem of inaccurate boundary identification and to eliminate the spurious pressure oscillation in the previously developed immersed smoothed point interpolation method(IS-PIM),a new sharp-interface IS-PIM combining mass conservation algorithm,called Sharp-ISPIM-Mass,is proposed in this work.Based on the so called sharp-interface method,the technique of quadratic local velocity reconstruction has been developed by combining with the mass conservation algorithm,which enables the present method improve the accuracy of the velocity field and satisfy the mass conservation condition near the boundary field.So the proposed method would not encounter the problem of spurious mass flux.In addition,a new form of FSI force evaluation considering pressure and viscous force to perform a whole function from the fluid domain to fictitious fluid domain is introduced,which makes the present method obtain more accurate results of FSI force than the original one.Through the numerical studies of a number of benchmark examples,the performance of the Sharp-ISPIM-Mass has been examined and illustrated.
基金Item Sponsored by Natural Science Foundation of Liaoning Province[No.20092002]the Program of Introducing Talents of Discipline to Universities[No.B07015]
文摘Aimed at the problem of short life of mixing head in KR mechanical mixing method for desulfurization of hot metal,a new type of mixing stir was proposed.CFD theory was used to simulate the characteristics of the fluid flow for the new type of stirring vessel of water model for KR mechanical desulfurization.Flow characteristics and structures of the flow field were investigated and compared with the traditional cross-flow type.The results show that the new type of impeller can not only improve the defects of the flow caused by stir structure of the traditional type,but also reduce the separation of mixing zone in the stirred tank and make the flow field more uniform to make the desulfurization more fully, thus shortening the mixing time,and improving the life of mixing head.Numerical simulation method has been proven to be sound by comparing with the experimental ones.
文摘In this paper, a split step ABCD matrix method is suggested to investigate Gaussian beam propagation in a Kerr type metamaterial medium. This method is based on dividing the medium interval into subsequent steps.Meanwhile, Gaussian beam profile in every step is obtained by finding the ABCD matrix of that particular step, and is used to find the ABCD matrix of the next step. Results of the suggested matrix method have been compared with the results of numerical split-step Fourier method for a Kerr medium, which indicates a good agreement. Then, we use the ABCD matrix to investigate Gaussian beams propagation in a Kerr type metamaterial, which is also in agreement with pervious results by other methods.