In this paper,we consider the indefinite least squares problem with quadratic constraint and its condition numbers.The conditions under which the problem has the unique solution are first presented.Then,the normwise,m...In this paper,we consider the indefinite least squares problem with quadratic constraint and its condition numbers.The conditions under which the problem has the unique solution are first presented.Then,the normwise,mixed,and componentwise condition numbers for solution and residual of this problem are derived.Numerical example is also provided to illustrate these results.展开更多
Two rice genotypes Huanghuazhan(HHZ, heat-resistant) and IR36(heat-susceptible) were subjected to high-temperature(HT, 40℃) and normal-temperature(NT, 32℃) treatments at the spikelet differentiation stage. HT treatm...Two rice genotypes Huanghuazhan(HHZ, heat-resistant) and IR36(heat-susceptible) were subjected to high-temperature(HT, 40℃) and normal-temperature(NT, 32℃) treatments at the spikelet differentiation stage. HT treatment inhibited spikelet differentiation, aggravated spikelet degeneration, reduced spikelet size, and disordered carbohydrate allocation. Meanwhile, HT treatment increased nonstructural carbohydrate content in leaves, but decreased that in stems and young panicles, and the same tendencies of sucrose and starch contents were observed in leaves and stem. However, HT treatment significantly increased the sucrose content and sharply decreased the glucose and fructose contents in young panicles. Lower activity levels of soluble acid invertase(EC3.2.1.26) and sucrose synthase(EC2.4.1.13) were observed under HT treatment. Moreover, HT treatment reduced the activities of key enzymes associated with glycolysis and the tricarboxylic acid cycle, which indicated sucrose consumption was inhibited in young panicles under HT treatment. Exogenous glucose and fructose applied under HT treatment increased the spikelet number more than exogenous sucrose. In conclusion, the results demonstrated that the reduction of spikelet number under high temperature was more affected by the decrease in sugar consumption than the blocking of sucrose transport. The impairment of sucrose hydrolysis was the main reason for the inhibition of sugar utilization.展开更多
Recently, Sun defined a new kind of refined Eulerian polynomials, namely,An(p,q)=∑π∈■np^odes(π)q^edes(π) for n ≥ 1, where Sn is the set of all permutations on {1, 2,..., n}, odes(π) and edes(π) enumerate the ...Recently, Sun defined a new kind of refined Eulerian polynomials, namely,An(p,q)=∑π∈■np^odes(π)q^edes(π) for n ≥ 1, where Sn is the set of all permutations on {1, 2,..., n}, odes(π) and edes(π) enumerate the number of descents of permutation π in odd and even positions, respectively. In this paper,we obtain an exponential generating function for An(p, q) and give an explicit formula for An(p, q)in terms of Eulerian polynomials An(q) and C(q), the generating function for Catalan numbers.In certain cases, we establish a connection between An(p, q) and An(p, 0) or An(0, q), and express the coefficients of An(0, q) by Eulerian numbers An,k. Consequently, this connection discovers a new relation between Euler numbers En and Eulerian numbers An,k.展开更多
Underground non-Darcy fluid flow has been observed and investigated for decades in the petroleum industry. It is deduced by analogy that the fluid flow in enhanced geothermal system (EGS) heat reservoirs may also be i...Underground non-Darcy fluid flow has been observed and investigated for decades in the petroleum industry. It is deduced by analogy that the fluid flow in enhanced geothermal system (EGS) heat reservoirs may also be in the non-Darcy regime under some conditions. In this paper, a transient 3D model was presented, taking into consideration the non-Darcy fluid flow in EGS heat reservoirs, to simulate the EGS long-term heat extraction process. Then, the non-Darcy flow behavior in water- and supercritical CO2 (SCCO2)-based EGSs was simulated and discussed. It is found that non-Darcy effects decrease the mass flow rate of the fluid injected and reduce the heat extraction rate of EGS as a flow resistance in addition to the Darcy resistance which is imposed to the seepage flow in EGS heat reservoirs. Compared with the water-EGS, the SCCO2-EGS are more prone to experiencing much stronger non-Darcy flow due to the much larger mobility of the SCCO2. The non-Darcy flow in SCCO2- EGSs may thus greatly reduce their heat extraction performance. Further, a criterion was analyzed and proposed to judge the onset of the non-Darcy flow in EGS heat reservoirs. The fluid flow rate and the initial thermal state of the reservoir were taken and the characteristic Forchheimer number of an EGS was calculated. If the calculated Forchheimer number is larger than 0.2, the fluid flow in EGS heat reservoirs experiences non-negligible non-Darcy flow characteristic.展开更多
In this paper, we present an approach that can handle Z-numbers in the context of multi-criteria decision-making problems. The concept of Z-number as an ordered pair Z=(A, B) of fuzzy numbers A and B is used, where A ...In this paper, we present an approach that can handle Z-numbers in the context of multi-criteria decision-making problems. The concept of Z-number as an ordered pair Z=(A, B) of fuzzy numbers A and B is used, where A is a linguistic value of a variable of interest and B is a linguistic value of the probability measure of A. As human beings, we communicate with each other by means of natural language using sentences like 'the journey from home to university most likely takes about half an hour.' The Z-numbers are converted to fuzzy numbers. Then the Z-TODIM and Z-TOPSIS are presented as a direct extension of the fuzzy TODIM and fuzzy TOPSIS, respectively. The proposed methods are applied to two case studies and compared with the standard approach using crisp values. The results obtained show the feasibility of the approach.展开更多
Natural convection in a square cavity is studied numerically with vertical hot walls and a cold partition located at the bottom or top walls. The effect of orientation of partition on isotherms, flow patterns, and hea...Natural convection in a square cavity is studied numerically with vertical hot walls and a cold partition located at the bottom or top walls. The effect of orientation of partition on isotherms, flow patterns, and heat transfer is analyzed for different fluids and Rayleigh numbers. The placement of partition is found to considerably influence the isotherms, flow patterns, and heat transfer. Heat transfer rate is observed always to increase when the partition is moved from bottom to top wall.展开更多
For any fixed Alfvén number, the local well-posedness is proved for the equations of threedimensional ideal incompressible magneto-hydrodynamics in a domain with boundaries. Under appropriate conditions, a smooth...For any fixed Alfvén number, the local well-posedness is proved for the equations of threedimensional ideal incompressible magneto-hydrodynamics in a domain with boundaries. Under appropriate conditions, a smooth solution is shown to exist in a time interval independent of the Alfvén number, and the solutions of the original system tend to the solutions of a two-dimensional Euler flow coupled with a linear transport equation as the Alfvén number goes to zero.展开更多
Effects of the orientation and apex angle on the settling velocity of conical particles in Bingham plas-tic fluids are numerically investigated over a Reynolds number range of 1 ≤Re ≤100, Bingham number range of 0 ...Effects of the orientation and apex angle on the settling velocity of conical particles in Bingham plas-tic fluids are numerically investigated over a Reynolds number range of 1 ≤Re ≤100, Bingham number range of 0 ≤ Bn ≤ 100, and cone angle range of 20 ≤α≤ 150°. Governing equations (of continuity and momentum) are solved numerically using the finite element method to obtain velocity and pressure fields that are postprocessed to obtain values of the drag coefficien.Futthermore, the effect of cone ori-entation on the flow field is visualized and explored in terms of streamline contours and the morphology of yielded/uny ielded regions. Finally, the obtai ned values of drag are correlated via a simple predictive expression in terms of the modified Reynolds number. The effect of the cone angle on drag is found to be moderate because the drag force acting on the lateral surface is a small fraction of the overall drag.展开更多
In the design of a hypersonic airliner that can considerably shorten the flight time,how to accurately predict the vehicle’s aerodynamic heating loads is of great significance.In this study,a new shock-stable flux sc...In the design of a hypersonic airliner that can considerably shorten the flight time,how to accurately predict the vehicle’s aerodynamic heating loads is of great significance.In this study,a new shock-stable flux scheme called the simple low dissipation advection upwind splitting method(SLAU)-M1 is proposed for the prediction of hypersonic aerodynamic heating load.Based on the construction of the SLAU scheme for low-speed simulations,SLAU-M1 improves the robustness of the mass flux against shock instability.After validating the code employed,several numerical test cases are conducted.The onedimensional(1D) sod shock tube case and the two-dimensional(2D) inviscid NACA0012 airfoil case show that SLAU-M1 features a high level of accuracy at both low and high speeds.To simulate the hypersonic viscous flow over a blunt cone,we adopt different aspect ratios(ARs) of cells near the shock.The results suggest that SLAU-M1 is much less sensitive to the AR of cells near the shock in predicting hypersonic aerodynamic heating loads.Moreover,the findings show that the theoretical value is considerably better than that of the other schemes.The hypersonic viscous flow over a 2D double ellipsoid case and that over the Hypersonic Flight Experiment vehicle case also indicate that SLAU-M1 exhibits a considerably high level of accuracy in hypersonic heating predictions.These properties suggest that SLAU-M1 promises to be widely used in the accurate prediction of the aerodynamic heating loads of hypersonic airliners.展开更多
In Kenya, rhinos are a nati onal treasure. Owing to massive poaching, the number of all five species of this mammal has dropped drastically across Africa. Among them, northern white rhinos are the most endangered. Las...In Kenya, rhinos are a nati onal treasure. Owing to massive poaching, the number of all five species of this mammal has dropped drastically across Africa. Among them, northern white rhinos are the most endangered. Last yeai;Sudan, the last male member of this species, died in Kenya.展开更多
The mass energy absorption coefficient (len=q), effective atomic number (ZPEAeff ), and electron density (NPEAeff ) of some biomolecules with potential application in radiation dosimetry were calculated for their phot...The mass energy absorption coefficient (len=q), effective atomic number (ZPEAeff ), and electron density (NPEAeff ) of some biomolecules with potential application in radiation dosimetry were calculated for their photon energy absorption (PEA) in the energy region of 1–20 MeV. It was noticed that the values of len=q, ZPEAeff , and NPEAeff vary with the energy and composition of the biomolecules. The results for ZPEAeff were compared with effective atomic numbers (ZPIeff ) owing to the photon interaction (PI). Significant differences were noted between ZPEAeff and ZPIeff in the energy region of 10–150 keV for all of the biomolecules involved. A maximum difference of 45.36% was observed at 50 keV for creatinine hydrochloride. Moreover, the studied attenuation parameters were found to be sharply affected at the K-absorption edge of relatively high-Z elements present in the biomolecules.展开更多
For the unsorted database quantum search with the unknown fraction λ of target items, there are mainly two kinds of methods, i.e., fixed-point and trail-and-error.(i) In terms of the fixed-point method, Yoder et al. ...For the unsorted database quantum search with the unknown fraction λ of target items, there are mainly two kinds of methods, i.e., fixed-point and trail-and-error.(i) In terms of the fixed-point method, Yoder et al. [Phys. Rev. Lett.113 210501(2014)] claimed that the quadratic speedup over classical algorithms has been achieved. However, in this paper, we point out that this is not the case, because the query complexity of Yoder’s algorithm is actually in O(1/λ01/2)rather than O(1/λ1/2), where λ0 is a known lower bound of λ.(ii) In terms of the trail-and-error method, currently the algorithm without randomness has to take more than 1 times queries or iterations than the algorithm with randomly selected parameters. For the above problems, we provide the first hybrid quantum search algorithm based on the fixed-point and trail-and-error methods, where the matched multiphase Grover operations are trialed multiple times and the number of iterations increases exponentially along with the number of trials. The upper bound of expected queries as well as the optimal parameters are derived. Compared with Yoder’s algorithm, the query complexity of our algorithm indeed achieves the optimal scaling in λ for quantum search, which reconfirms the practicality of the fixed-point method. In addition, our algorithm also does not contain randomness, and compared with the existing deterministic algorithm, the query complexity can be reduced by about 1/3. Our work provides a new idea for the research on fixed-point and trial-and-error quantum search.展开更多
Yusuf Mohamed, a 45-year-old resident of Nairobi, has been a consumer of Chinese products and services for more than a decade. Chinese electronics, food and beer are all favorites in Mohamed s life. He is just one of ...Yusuf Mohamed, a 45-year-old resident of Nairobi, has been a consumer of Chinese products and services for more than a decade. Chinese electronics, food and beer are all favorites in Mohamed s life. He is just one of a growing number of Kenyans who rely on Chinese goods and services.展开更多
Ionic liquids (ILs) have received a great deal of attention because they are less-volatile, less-flammable, have low toxicity and unique solubility for many organic and inorganic materials, and these properties allow ...Ionic liquids (ILs) have received a great deal of attention because they are less-volatile, less-flammable, have low toxicity and unique solubility for many organic and inorganic materials, and these properties allow them to be used in various fields of sustainable sciences. Remarkable progress in the science of ILs has been accomplished during the past two decades;the number of publications of ILs reached more than 90,000 since 1999 to be present [1]. ILs are nowwell recognized as essential players in the fields of environmental benign synthesis, catalysts, extraction, electrochemistry, and biotechnology, and they also attract much attention as a key technology to promote the spread of renewable energy.展开更多
A robust topology optimization design framework is developed to solve lightweight structural design problems under uncertain conditions. To enhance the calculation accuracy and flexibility of the statistical moments o...A robust topology optimization design framework is developed to solve lightweight structural design problems under uncertain conditions. To enhance the calculation accuracy and flexibility of the statistical moments of robust analysis, number theory integral method is applied to sample point selection and weight assignment. Both the structure topology optimization and number theory integral methods are combined to form a new robust topology optimization method. A suspension control arm problem is provided as a demonstration of robust topology optimization methods under loading uncertainties. Based on the results of deterministic and robust topology optimization, it is demonstrated that the proposed robust topology optimization method can produce a more robust design than that obtained by deterministic topology optimization. It is also found that this new approach is easy to apply in the existing commercial topology optimization software and thus feasible in practical engineering problems.展开更多
The adaptive simpler block GMRES method was investigated by Zhong et al.(J Comput Appl Math 282:139-156, 2015) where the condition number of the adaptively chosen basis for the Krylov subspace was evaluated. In this p...The adaptive simpler block GMRES method was investigated by Zhong et al.(J Comput Appl Math 282:139-156, 2015) where the condition number of the adaptively chosen basis for the Krylov subspace was evaluated. In this paper, the new upper bound for the condition number is investigated. Numerical tests show that the new upper bound is tighter.展开更多
基金National Natural Science Foundation of China(Grant No.11671060)the Fundamental Research Funds for the Central Universities(Grant No.106112015CDJXY100003).
文摘In this paper,we consider the indefinite least squares problem with quadratic constraint and its condition numbers.The conditions under which the problem has the unique solution are first presented.Then,the normwise,mixed,and componentwise condition numbers for solution and residual of this problem are derived.Numerical example is also provided to illustrate these results.
基金funded by the National Key Research and Development Program of China(Grant No.2017YFD0300409)the Special Fund for China Agricultural Research System(Grant No.CARS-01-07B)+2 种基金Agricultural Sciences and Technologies Innovation Program of Chinese Academy of Agricultural Sciences,National Natural Science Foundation(Grant No.31701374)Zhejiang Provincial Natural Science Foundation(Grant No.LY16C130006)Basic Research Foundation of National Commonweal Research Institute(Grant No.2017RG004-4)in China。
文摘Two rice genotypes Huanghuazhan(HHZ, heat-resistant) and IR36(heat-susceptible) were subjected to high-temperature(HT, 40℃) and normal-temperature(NT, 32℃) treatments at the spikelet differentiation stage. HT treatment inhibited spikelet differentiation, aggravated spikelet degeneration, reduced spikelet size, and disordered carbohydrate allocation. Meanwhile, HT treatment increased nonstructural carbohydrate content in leaves, but decreased that in stems and young panicles, and the same tendencies of sucrose and starch contents were observed in leaves and stem. However, HT treatment significantly increased the sucrose content and sharply decreased the glucose and fructose contents in young panicles. Lower activity levels of soluble acid invertase(EC3.2.1.26) and sucrose synthase(EC2.4.1.13) were observed under HT treatment. Moreover, HT treatment reduced the activities of key enzymes associated with glycolysis and the tricarboxylic acid cycle, which indicated sucrose consumption was inhibited in young panicles under HT treatment. Exogenous glucose and fructose applied under HT treatment increased the spikelet number more than exogenous sucrose. In conclusion, the results demonstrated that the reduction of spikelet number under high temperature was more affected by the decrease in sugar consumption than the blocking of sucrose transport. The impairment of sucrose hydrolysis was the main reason for the inhibition of sugar utilization.
基金Supported by"Liaoning BaiQianWan Talents Program"and by the Fundamental Research Funds for the Central Universities(Grant No.3132019323).
文摘Recently, Sun defined a new kind of refined Eulerian polynomials, namely,An(p,q)=∑π∈■np^odes(π)q^edes(π) for n ≥ 1, where Sn is the set of all permutations on {1, 2,..., n}, odes(π) and edes(π) enumerate the number of descents of permutation π in odd and even positions, respectively. In this paper,we obtain an exponential generating function for An(p, q) and give an explicit formula for An(p, q)in terms of Eulerian polynomials An(q) and C(q), the generating function for Catalan numbers.In certain cases, we establish a connection between An(p, q) and An(p, 0) or An(0, q), and express the coefficients of An(0, q) by Eulerian numbers An,k. Consequently, this connection discovers a new relation between Euler numbers En and Eulerian numbers An,k.
基金This work was supported by the National Key R&D Program of China (2018YFB1501804)the Strategic Priority Research Program of Chinese Academy of Sciences (XDA21060700)+1 种基金the National Natural Science Foundation of China (Grant No. 41702256)the Natural Science Foundation of Guangdong Province (2017A030310328).
文摘Underground non-Darcy fluid flow has been observed and investigated for decades in the petroleum industry. It is deduced by analogy that the fluid flow in enhanced geothermal system (EGS) heat reservoirs may also be in the non-Darcy regime under some conditions. In this paper, a transient 3D model was presented, taking into consideration the non-Darcy fluid flow in EGS heat reservoirs, to simulate the EGS long-term heat extraction process. Then, the non-Darcy flow behavior in water- and supercritical CO2 (SCCO2)-based EGSs was simulated and discussed. It is found that non-Darcy effects decrease the mass flow rate of the fluid injected and reduce the heat extraction rate of EGS as a flow resistance in addition to the Darcy resistance which is imposed to the seepage flow in EGS heat reservoirs. Compared with the water-EGS, the SCCO2-EGS are more prone to experiencing much stronger non-Darcy flow due to the much larger mobility of the SCCO2. The non-Darcy flow in SCCO2- EGSs may thus greatly reduce their heat extraction performance. Further, a criterion was analyzed and proposed to judge the onset of the non-Darcy flow in EGS heat reservoirs. The fluid flow rate and the initial thermal state of the reservoir were taken and the characteristic Forchheimer number of an EGS was calculated. If the calculated Forchheimer number is larger than 0.2, the fluid flow in EGS heat reservoirs experiences non-negligible non-Darcy flow characteristic.
基金the Brazilian Agency CNPq(No.309161/2015-0)the Local Agency of the State of Espirito Santo FAPES(No.039/2016).
文摘In this paper, we present an approach that can handle Z-numbers in the context of multi-criteria decision-making problems. The concept of Z-number as an ordered pair Z=(A, B) of fuzzy numbers A and B is used, where A is a linguistic value of a variable of interest and B is a linguistic value of the probability measure of A. As human beings, we communicate with each other by means of natural language using sentences like 'the journey from home to university most likely takes about half an hour.' The Z-numbers are converted to fuzzy numbers. Then the Z-TODIM and Z-TOPSIS are presented as a direct extension of the fuzzy TODIM and fuzzy TOPSIS, respectively. The proposed methods are applied to two case studies and compared with the standard approach using crisp values. The results obtained show the feasibility of the approach.
文摘Natural convection in a square cavity is studied numerically with vertical hot walls and a cold partition located at the bottom or top walls. The effect of orientation of partition on isotherms, flow patterns, and heat transfer is analyzed for different fluids and Rayleigh numbers. The placement of partition is found to considerably influence the isotherms, flow patterns, and heat transfer. Heat transfer rate is observed always to increase when the partition is moved from bottom to top wall.
基金supported by the Israel Science Foundation-National Natural Science Foundation of China Joint Research Program (Grant No. 11761141008)supported by the National Basic Research Program of China (Grant No. 2014CB745002)+2 种基金National Natural Science Foundation of China (Grant No. 11631008)supported by National Natural Science Foundation of China (Grant Nos. 11571046, 11471028 and 11671225)Beijing Natural Science Foundation (Grant No. 1182004).
文摘For any fixed Alfvén number, the local well-posedness is proved for the equations of threedimensional ideal incompressible magneto-hydrodynamics in a domain with boundaries. Under appropriate conditions, a smooth solution is shown to exist in a time interval independent of the Alfvén number, and the solutions of the original system tend to the solutions of a two-dimensional Euler flow coupled with a linear transport equation as the Alfvén number goes to zero.
文摘Effects of the orientation and apex angle on the settling velocity of conical particles in Bingham plas-tic fluids are numerically investigated over a Reynolds number range of 1 ≤Re ≤100, Bingham number range of 0 ≤ Bn ≤ 100, and cone angle range of 20 ≤α≤ 150°. Governing equations (of continuity and momentum) are solved numerically using the finite element method to obtain velocity and pressure fields that are postprocessed to obtain values of the drag coefficien.Futthermore, the effect of cone ori-entation on the flow field is visualized and explored in terms of streamline contours and the morphology of yielded/uny ielded regions. Finally, the obtai ned values of drag are correlated via a simple predictive expression in terms of the modified Reynolds number. The effect of the cone angle on drag is found to be moderate because the drag force acting on the lateral surface is a small fraction of the overall drag.
基金the National Natural Science Foundation of China (Grant No.11802245).
文摘In the design of a hypersonic airliner that can considerably shorten the flight time,how to accurately predict the vehicle’s aerodynamic heating loads is of great significance.In this study,a new shock-stable flux scheme called the simple low dissipation advection upwind splitting method(SLAU)-M1 is proposed for the prediction of hypersonic aerodynamic heating load.Based on the construction of the SLAU scheme for low-speed simulations,SLAU-M1 improves the robustness of the mass flux against shock instability.After validating the code employed,several numerical test cases are conducted.The onedimensional(1D) sod shock tube case and the two-dimensional(2D) inviscid NACA0012 airfoil case show that SLAU-M1 features a high level of accuracy at both low and high speeds.To simulate the hypersonic viscous flow over a blunt cone,we adopt different aspect ratios(ARs) of cells near the shock.The results suggest that SLAU-M1 is much less sensitive to the AR of cells near the shock in predicting hypersonic aerodynamic heating loads.Moreover,the findings show that the theoretical value is considerably better than that of the other schemes.The hypersonic viscous flow over a 2D double ellipsoid case and that over the Hypersonic Flight Experiment vehicle case also indicate that SLAU-M1 exhibits a considerably high level of accuracy in hypersonic heating predictions.These properties suggest that SLAU-M1 promises to be widely used in the accurate prediction of the aerodynamic heating loads of hypersonic airliners.
文摘In Kenya, rhinos are a nati onal treasure. Owing to massive poaching, the number of all five species of this mammal has dropped drastically across Africa. Among them, northern white rhinos are the most endangered. Last yeai;Sudan, the last male member of this species, died in Kenya.
文摘The mass energy absorption coefficient (len=q), effective atomic number (ZPEAeff ), and electron density (NPEAeff ) of some biomolecules with potential application in radiation dosimetry were calculated for their photon energy absorption (PEA) in the energy region of 1–20 MeV. It was noticed that the values of len=q, ZPEAeff , and NPEAeff vary with the energy and composition of the biomolecules. The results for ZPEAeff were compared with effective atomic numbers (ZPIeff ) owing to the photon interaction (PI). Significant differences were noted between ZPEAeff and ZPIeff in the energy region of 10–150 keV for all of the biomolecules involved. A maximum difference of 45.36% was observed at 50 keV for creatinine hydrochloride. Moreover, the studied attenuation parameters were found to be sharply affected at the K-absorption edge of relatively high-Z elements present in the biomolecules.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11504430 and 61502526)the National Basic Research Program of China(Grant No.2013CB338002)。
文摘For the unsorted database quantum search with the unknown fraction λ of target items, there are mainly two kinds of methods, i.e., fixed-point and trail-and-error.(i) In terms of the fixed-point method, Yoder et al. [Phys. Rev. Lett.113 210501(2014)] claimed that the quadratic speedup over classical algorithms has been achieved. However, in this paper, we point out that this is not the case, because the query complexity of Yoder’s algorithm is actually in O(1/λ01/2)rather than O(1/λ1/2), where λ0 is a known lower bound of λ.(ii) In terms of the trail-and-error method, currently the algorithm without randomness has to take more than 1 times queries or iterations than the algorithm with randomly selected parameters. For the above problems, we provide the first hybrid quantum search algorithm based on the fixed-point and trail-and-error methods, where the matched multiphase Grover operations are trialed multiple times and the number of iterations increases exponentially along with the number of trials. The upper bound of expected queries as well as the optimal parameters are derived. Compared with Yoder’s algorithm, the query complexity of our algorithm indeed achieves the optimal scaling in λ for quantum search, which reconfirms the practicality of the fixed-point method. In addition, our algorithm also does not contain randomness, and compared with the existing deterministic algorithm, the query complexity can be reduced by about 1/3. Our work provides a new idea for the research on fixed-point and trial-and-error quantum search.
文摘Yusuf Mohamed, a 45-year-old resident of Nairobi, has been a consumer of Chinese products and services for more than a decade. Chinese electronics, food and beer are all favorites in Mohamed s life. He is just one of a growing number of Kenyans who rely on Chinese goods and services.
文摘Ionic liquids (ILs) have received a great deal of attention because they are less-volatile, less-flammable, have low toxicity and unique solubility for many organic and inorganic materials, and these properties allow them to be used in various fields of sustainable sciences. Remarkable progress in the science of ILs has been accomplished during the past two decades;the number of publications of ILs reached more than 90,000 since 1999 to be present [1]. ILs are nowwell recognized as essential players in the fields of environmental benign synthesis, catalysts, extraction, electrochemistry, and biotechnology, and they also attract much attention as a key technology to promote the spread of renewable energy.
基金Supported by the National Key Research and Development Program of China (2017YFB0103704)the National Natural Science Foundation of China (51675044).
文摘A robust topology optimization design framework is developed to solve lightweight structural design problems under uncertain conditions. To enhance the calculation accuracy and flexibility of the statistical moments of robust analysis, number theory integral method is applied to sample point selection and weight assignment. Both the structure topology optimization and number theory integral methods are combined to form a new robust topology optimization method. A suspension control arm problem is provided as a demonstration of robust topology optimization methods under loading uncertainties. Based on the results of deterministic and robust topology optimization, it is demonstrated that the proposed robust topology optimization method can produce a more robust design than that obtained by deterministic topology optimization. It is also found that this new approach is easy to apply in the existing commercial topology optimization software and thus feasible in practical engineering problems.
基金This work was supported by the National Natural Science Foundation of China(11701320)the Shandong Provincial Natural Science Foundation of China(ZR2016AM04).
文摘The adaptive simpler block GMRES method was investigated by Zhong et al.(J Comput Appl Math 282:139-156, 2015) where the condition number of the adaptively chosen basis for the Krylov subspace was evaluated. In this paper, the new upper bound for the condition number is investigated. Numerical tests show that the new upper bound is tighter.