Antibiotics are crucial medications for preventing and treating bacterial infections.However,due to their inherent resistance to degradation,they are also a major component of water pollutants.Semiconductor photocatal...Antibiotics are crucial medications for preventing and treating bacterial infections.However,due to their inherent resistance to degradation,they are also a major component of water pollutants.Semiconductor photocatalysis is considered to be an important green technology for sewage treatment.In this study,BiVO_(4)/Cd S Z-type heterojunction was synthesized and applied in the photocatalytic degradation of tetracycline hydrochloride(TCH).The Z-type heterojunction not only facilitates the separation of photogenerated charges,but also preserves photogenerated electrons with strong reduction capability and photogenerated holes with high oxidation capability.Following visible light irradiation for 90 min,the efficiency of BiVO_(4)/Cd S photocatalytic degradation of TCH reached 93.1%.Moreover,BiVO_(4)/Cd S demonstrates notable degradation efficacy toward other quinolone antibiotics.Free radical trapping experiments and EPR test results suggest that superoxide radicals,hydroxyl radicals,photogenerated electrons,and holes serve as the primary active species in the photocatalytic degradation process of tetracycline hydrochloride.This study offers valuable insights into the development of Z-type heterojunction photocatalysts for the efficient degradation of tetracycline hydrochloride.展开更多
The Z-type ferrites of nominal composition Ba3Co2 Fe24O41+x wt% Bi2O3, where x=0.25, 0.5, 1.0, 1.5, 2.0, were prepared by conventional ceramic processes. The influence of Bi2O3 content on the bulk densities, microstru...The Z-type ferrites of nominal composition Ba3Co2 Fe24O41+x wt% Bi2O3, where x=0.25, 0.5, 1.0, 1.5, 2.0, were prepared by conventional ceramic processes. The influence of Bi2O3 content on the bulk densities, microstructures, magnetic and dielectric properties of Z-type ferrite samples were systematically examined so as to obtain materials with low magnetic and dielectric loss tangent over a frequency ranging from 600 to 800 MHz. The experimental results showed that addition of Bi2O3 lowered the sintering temperature(1 020 ℃) and then reduced the average grain size(<2 μm) and enhanced the resistivity(>2.68×10^8 Ω·cm) dramatically, which consequently decreased the magnetic and dielectric loss. Additionally, the low loss factors were observed at the Bi2O3 content x = 1.0, i e, tan δμ/μ’=0.013 and tan δε/ε’= 0.001 at 800 MHz, and such materials could be used for antennas miniaturization from 600 to 800 MHz.展开更多
To design and check the strength of the Z-type guide arm of interconnected air suspensions for semi-trailers rapidly and effectively,this paper proposes the analytical calculation methods of its deformation and stress...To design and check the strength of the Z-type guide arm of interconnected air suspensions for semi-trailers rapidly and effectively,this paper proposes the analytical calculation methods of its deformation and stress.First,based on the guide arm structure,it is marked as two parts by its mountpoint on the axle as the boundary.The part containing the eye was marked as Arm-1.The other part was marked as Arm-2.Then the analytical formulas of their stiffness and stress were derived,respectively.With a case study,the deformation and the stress were computed and simulated.The results show that the values computed are close to those simulated.The relative deviations are not more than 5.0%.The results show that the analytical formulas are acceptable.Moreover,it can be seen that for the superimposed Arm-1,when the other structural parameters are fixed,the position of the maximum stress is affected by the thickness ratio of the end thickness to the root thickness for each piece.Finally,a stiffness test was performed on the Z-type guide arm.The results show that the computed stiffness values are closed to those tested and the relative deviations are not more than 3.5%.This further verified the validity of the established model and methods.展开更多
In the present paper,an epidemic model with Z-type control mechanism has been pro- posed and analyzed to explore the disease control strategy on an infectious disease outbreak.The uncontrolled model can have a disease...In the present paper,an epidemic model with Z-type control mechanism has been pro- posed and analyzed to explore the disease control strategy on an infectious disease outbreak.The uncontrolled model can have a disease-free equilibrium and an endemic equilibrium.The expression of the basic reproduction number and the conditions for the stability of the equilibria are derived.It is also observed that the disease-free equilibrium is globally asymptotically stable if R0<1,whereas the endemic equilibrium is globally asymptotically stable if R0>1.The model is further improved by considering Z-control mechanism and investigated.Disease can be controlled by using Z-control while the basic reproduction of the uncontrolled system is greater than unity.The positivity conditions of the solutions are derived and the basin of attraction for successful implementation of Z-control mechanism is also investigated.To verify the analytical findings,extensive numerical simulations on the model are carried out.展开更多
In this study,the Z-type control method is applied to an intraguild crop-pest-natural enemy model,assuming that the natural enemy can predate on both crop and pest populations.For this purpose,the indirect Z-type cont...In this study,the Z-type control method is applied to an intraguild crop-pest-natural enemy model,assuming that the natural enemy can predate on both crop and pest populations.For this purpose,the indirect Z-type controller is considered in the natural enemy population.After providing the design function for the crop-pest-natural enemy model with Z-control,we find the analytical expression of the update parameter.The findings indicate that the uncontrolled system can produce chaos through perioddoubling bifurcation due to crop over-consumption by the pest population.We draw a Poincare map to confirm the occurrence of chaos and compute the maximum Lyapunov exponent.As the observations further indicate that the pest population can be controlled by using an indirect Z-control mechanism in the natural enemy population,we postulate that,if natural enemy abundance can be governed by the update parameter,any desired pest population abundance can be achieved through the proposed Z-type controller,thus controlling the pest.To verify these assertions,extensive numerical simulations are performed to explore the potential for practical application of the proposed Z-type controller.展开更多
In the present study,we extend the order-preserving(OP)criterion proposed in our latest studies to the WENO-Z-type schemes.Firstly,we innovatively present the concept of the generalized mapped WENO schemes by rewritin...In the present study,we extend the order-preserving(OP)criterion proposed in our latest studies to the WENO-Z-type schemes.Firstly,we innovatively present the concept of the generalized mapped WENO schemes by rewriting the Ztype weights in a uniform formula from the perspective of the mapping relation.Then,we naturally introduce the OP criterion to improve the WENO-Z-type schemes,and the resultant schemes are denoted as MOP-GMWENO-X,where the notation“X”is used to identify the version of the existing WENO-Z-type scheme in this paper.Finally,extensive numerical experiments have been conducted to demonstrate the benefits of these new schemes.We draw the conclusion that,the convergence properties of the proposed schemes are equivalent to the corresponding WENO-X schemes.The major benefit of the new schemes is that they have the capacity to achieve high resolutions and simultaneously remove spurious oscillations for long simulations.The new schemes have the additional benefit that they can greatly decrease the post-shock oscillations on solving 2D Euler problems with strong shock waves.展开更多
基金financially supported by the Natural Science Foundation of Shanxi Province(No.202203021221134)。
文摘Antibiotics are crucial medications for preventing and treating bacterial infections.However,due to their inherent resistance to degradation,they are also a major component of water pollutants.Semiconductor photocatalysis is considered to be an important green technology for sewage treatment.In this study,BiVO_(4)/Cd S Z-type heterojunction was synthesized and applied in the photocatalytic degradation of tetracycline hydrochloride(TCH).The Z-type heterojunction not only facilitates the separation of photogenerated charges,but also preserves photogenerated electrons with strong reduction capability and photogenerated holes with high oxidation capability.Following visible light irradiation for 90 min,the efficiency of BiVO_(4)/Cd S photocatalytic degradation of TCH reached 93.1%.Moreover,BiVO_(4)/Cd S demonstrates notable degradation efficacy toward other quinolone antibiotics.Free radical trapping experiments and EPR test results suggest that superoxide radicals,hydroxyl radicals,photogenerated electrons,and holes serve as the primary active species in the photocatalytic degradation process of tetracycline hydrochloride.This study offers valuable insights into the development of Z-type heterojunction photocatalysts for the efficient degradation of tetracycline hydrochloride.
基金Funded by the National Natural Science Foundation of China(No.U1435209)Wuhan Science and Technology Program(No.2014010101010018)Fundamental Research Funds for the Central Universities(No.2015ZZGH007)
文摘The Z-type ferrites of nominal composition Ba3Co2 Fe24O41+x wt% Bi2O3, where x=0.25, 0.5, 1.0, 1.5, 2.0, were prepared by conventional ceramic processes. The influence of Bi2O3 content on the bulk densities, microstructures, magnetic and dielectric properties of Z-type ferrite samples were systematically examined so as to obtain materials with low magnetic and dielectric loss tangent over a frequency ranging from 600 to 800 MHz. The experimental results showed that addition of Bi2O3 lowered the sintering temperature(1 020 ℃) and then reduced the average grain size(<2 μm) and enhanced the resistivity(>2.68×10^8 Ω·cm) dramatically, which consequently decreased the magnetic and dielectric loss. Additionally, the low loss factors were observed at the Bi2O3 content x = 1.0, i e, tan δμ/μ’=0.013 and tan δε/ε’= 0.001 at 800 MHz, and such materials could be used for antennas miniaturization from 600 to 800 MHz.
基金This work was supported by National Natural Science Foundation of China[Grant No.51575325].
文摘To design and check the strength of the Z-type guide arm of interconnected air suspensions for semi-trailers rapidly and effectively,this paper proposes the analytical calculation methods of its deformation and stress.First,based on the guide arm structure,it is marked as two parts by its mountpoint on the axle as the boundary.The part containing the eye was marked as Arm-1.The other part was marked as Arm-2.Then the analytical formulas of their stiffness and stress were derived,respectively.With a case study,the deformation and the stress were computed and simulated.The results show that the values computed are close to those simulated.The relative deviations are not more than 5.0%.The results show that the analytical formulas are acceptable.Moreover,it can be seen that for the superimposed Arm-1,when the other structural parameters are fixed,the position of the maximum stress is affected by the thickness ratio of the end thickness to the root thickness for each piece.Finally,a stiffness test was performed on the Z-type guide arm.The results show that the computed stiffness values are closed to those tested and the relative deviations are not more than 3.5%.This further verified the validity of the established model and methods.
文摘In the present paper,an epidemic model with Z-type control mechanism has been pro- posed and analyzed to explore the disease control strategy on an infectious disease outbreak.The uncontrolled model can have a disease-free equilibrium and an endemic equilibrium.The expression of the basic reproduction number and the conditions for the stability of the equilibria are derived.It is also observed that the disease-free equilibrium is globally asymptotically stable if R0<1,whereas the endemic equilibrium is globally asymptotically stable if R0>1.The model is further improved by considering Z-control mechanism and investigated.Disease can be controlled by using Z-control while the basic reproduction of the uncontrolled system is greater than unity.The positivity conditions of the solutions are derived and the basin of attraction for successful implementation of Z-control mechanism is also investigated.To verify the analytical findings,extensive numerical simulations on the model are carried out.
基金Dibyendu Sekhar Mandal thankfully acknowledges the University Grants Commission(Rajiv Gandhi National Fellowship for SC/ST Candidates)of India(Grant/Award Number:F1-17.1/2013-14/RGNF-2013-14-SC-WES-53863/(SA-III/Website)for the financial assistance in the form of Senior Research FellowshipA.Chekroun and M.Helal are supported by the DGRSDT,Algeria.
文摘In this study,the Z-type control method is applied to an intraguild crop-pest-natural enemy model,assuming that the natural enemy can predate on both crop and pest populations.For this purpose,the indirect Z-type controller is considered in the natural enemy population.After providing the design function for the crop-pest-natural enemy model with Z-control,we find the analytical expression of the update parameter.The findings indicate that the uncontrolled system can produce chaos through perioddoubling bifurcation due to crop over-consumption by the pest population.We draw a Poincare map to confirm the occurrence of chaos and compute the maximum Lyapunov exponent.As the observations further indicate that the pest population can be controlled by using an indirect Z-control mechanism in the natural enemy population,we postulate that,if natural enemy abundance can be governed by the update parameter,any desired pest population abundance can be achieved through the proposed Z-type controller,thus controlling the pest.To verify these assertions,extensive numerical simulations are performed to explore the potential for practical application of the proposed Z-type controller.
文摘In the present study,we extend the order-preserving(OP)criterion proposed in our latest studies to the WENO-Z-type schemes.Firstly,we innovatively present the concept of the generalized mapped WENO schemes by rewriting the Ztype weights in a uniform formula from the perspective of the mapping relation.Then,we naturally introduce the OP criterion to improve the WENO-Z-type schemes,and the resultant schemes are denoted as MOP-GMWENO-X,where the notation“X”is used to identify the version of the existing WENO-Z-type scheme in this paper.Finally,extensive numerical experiments have been conducted to demonstrate the benefits of these new schemes.We draw the conclusion that,the convergence properties of the proposed schemes are equivalent to the corresponding WENO-X schemes.The major benefit of the new schemes is that they have the capacity to achieve high resolutions and simultaneously remove spurious oscillations for long simulations.The new schemes have the additional benefit that they can greatly decrease the post-shock oscillations on solving 2D Euler problems with strong shock waves.
