In this study,α-TeO2：Ho3＋/Yb3＋,α-TeO2：Eu3＋ andα-TeO2：Ho3＋/Yb3＋/Eu3＋ nanoparticles were prepared via a simple hydrothermal process. The up- and down-conversion properties of the as-prepared nanoparticles we...In this study,α-TeO2：Ho3＋/Yb3＋,α-TeO2：Eu3＋ andα-TeO2：Ho3＋/Yb3＋/Eu3＋ nanoparticles were prepared via a simple hydrothermal process. The up- and down-conversion properties of the as-prepared nanoparticles were tested at room temperature un-der a near-infrared photo source （980 nm） and UV-vis photo source, respectively.The results indicated thatα-TeO2 NPs were a kind of outstanding host material for both up- and down-conversion luminescence. Theα-TeO2：Ho3＋/Yb3＋nanoparticles showed sharp up-conversion emission at 545 and 660 nm under 980 nm excitation, ascribed to the5S2→5I8 and5F5→5I8（Ho3＋） transitions, and weaker down-conversion emission at 545 nm under 455 nm excitation, ascribed to the5S2→5I8（Ho3＋） transitions. Theα-TeO2：Eu3＋nanoparticles showed strong down-conversion emission at 592 and 615 nm under 395 nm excitation, attributed to the5D0→7F1 and 5D0→7F2 （Eu3＋） transitions. Possessing the advantages of these two luminescent materials, the as-prepared tri-doped samples ofα-TeO2：0.5Ho3＋/10Yb3＋/3Eu3＋ （mol.%）nanoparticles could successfully emit visible light via both up- and down-conversion modes.展开更多
During the boreal summer,intraseasonal oscillations exhibit significant interannual variations in intensity over two key regions:the central-western equatorial Pacific(5°S-5°N,150°E-150°W)and the s...During the boreal summer,intraseasonal oscillations exhibit significant interannual variations in intensity over two key regions:the central-western equatorial Pacific(5°S-5°N,150°E-150°W)and the subtropical Northwestern Pacific(10°-20°N,130°E-175°W).The former is well-documented and considered to be influenced by the ENSO,while the latter has received comparatively less attention and is likely influenced by the Pacific Meridional Mode(PMM),as suggested by partial correlation analysis results.To elucidate the physical processes responsible for the enhanced(weakened)intraseasonal convection over the subtropical northwestern Pacific during warm(cold)PMM years,the authors employed a moisture budget analysis.The findings reveal that during warm PMM years,there is an increase in summer-mean moisture over the subtropical northwestern Pacific.This increase interacts with intensified vertical motion perturbations in the region,leading to greater vertical moisture advection in the lower troposphere and consequently resulting in convective instability.Such a process is pivotal in amplifying intraseasonal convection anomalies.The observational findings were further verified by model experiments forced by PMM-like sea surface temperature patterns.展开更多
Objective: To develop a best-evidence-based optimal nutrition management plan for patients with chronic heart failure, apply it in clinical practice, and evaluate its effectiveness. Methods: Use the KTA knowledge tran...Objective: To develop a best-evidence-based optimal nutrition management plan for patients with chronic heart failure, apply it in clinical practice, and evaluate its effectiveness. Methods: Use the KTA knowledge translation model to guide evidence-based practice in nutrition management, and compare the nutritional status, cardiac function status, quality of life, and quality review indicators of chronic heart failure patients before and after the application of evidence. Results: After the application of evidence, the nutritional status indicators (MNA-SF score, albumin, hemoglobin) of two groups of heart failure patients significantly increased compared to before the application of evidence, with statistically significant differences (p Conclusion: The KTA knowledge translation model provides methodological guidance for the implementation of evidence-based practice for heart failure patients. This evidence-based practice project is beneficial for improving the outcomes of malnutrition in chronic heart failure patients and is conducive to standardizing nursing pathways, thereby promoting the improvement of nursing quality.展开更多
In order to enhance the control performance of piezo-positioning system,the influence of hysteresis characteristics and its compensation method are studied.Hammerstein model is used to represent the dynamic hysteresis...In order to enhance the control performance of piezo-positioning system,the influence of hysteresis characteristics and its compensation method are studied.Hammerstein model is used to represent the dynamic hysteresis nonlinear characteristics of piezo-positioning actuator.The static nonlinear part and dynamic linear part of the Hammerstein model are represented by models obtained through the Prandtl-Ishlinskii(PI)model and Hankel matrix system identification method,respectively.This model demonstrates good generalization capability for typical input frequencies below 200 Hz.A sliding mode inverse compensation tracking control strategy based on P-I inverse model and integral augmentation is proposed.Experimental results show that compared with PID inverse compensation control and sliding mode control without inverse compensation,the sliding mode inverse compensation control has a more ideal step response and no overshoot,moreover,the settling time is only 6.2 ms.In the frequency domain,the system closed-loop tracking bandwidth reaches 119.9 Hz,and the disturbance rejection bandwidth reaches 86.2 Hz.The proposed control strategy can effectively compensate the hysteresis nonlinearity,and improve the tracking accuracy and antidisturbance capability of piezo-positioning system.展开更多
We apply the WKB approximation method,matrix method,and finite difference method to study the gravitational quasi-normal modes of charged spherically symmetric black holes surrounded by quintessence fluid in Rastall g...We apply the WKB approximation method,matrix method,and finite difference method to study the gravitational quasi-normal modes of charged spherically symmetric black holes surrounded by quintessence fluid in Rastall gravity.By comparing the spherically symmetric spacetime metric of charged black holes surrounded by quintessence fluid in Rastall gravity with that of general relativity,we can find that the modifications to general relativity in this modified gravity theory can be described by parameters such asλ,Q,and C_(a),etc.In four-dimensional spacetime,we investigate the impact of charge Q and parameter C_(a) on the gravitational quasi-normal modes of charged black holes surrounded by quintessence field in Rastall gravity.The aim is to search for observational evidence of such black holes in astrophysical observations and,consequently,test the validity of Rastall theory.In five-dimensional(5D)spacetime,we study the impact of the parameter C_(a) on the gravitational quasi-normal modes of Rastall black holes surrounded by quintessence field and summarize the corresponding variation patterns.展开更多
In the process of cultural and tourism project construction,intelligent construction technology has gradually shown strong advantages.The effective application of this technology not only greatly improves the construc...In the process of cultural and tourism project construction,intelligent construction technology has gradually shown strong advantages.The effective application of this technology not only greatly improves the construction efficiency and quality of cultural and tourism projects,but also effectively controls construction costs,laying a solid foundation for the green,low-carbon,and sustainable development of the cultural and tourism industry.The article analyzes the current situation of cultural and tourism project construction,proposes the advantages of intelligent construction and its application in the construction mode of cultural and tourism projects,aiming to provide reliable guidance for the sustainable development of cultural and tourism projects.展开更多
Objective:To investigate the delivery modes of women with repeat pregnancies involving uterine scars and their effects on both mothers and neonates.Methods:A study was conducted on 100 patients treated at Shenzhen Mat...Objective:To investigate the delivery modes of women with repeat pregnancies involving uterine scars and their effects on both mothers and neonates.Methods:A study was conducted on 100 patients treated at Shenzhen Maternity and Child Healthcare Hospital from July 2023 to July 2024.The participants were divided into a control group and an observation group,with 50 cases in each.The division was based on the indications for prior cesarean section,cervical maturity,postpartum complications,and thickness of the cesarean scar.The control group underwent cesarean delivery,while the observation group experienced vaginal delivery.The two groups were compared in terms of intrapartum blood loss,postpartum blood loss within 2 hours,length of hospital stay,Apgar scores at 1-minute post-birth,and incidences of neonatal fever and jaundice.Results:The observation group had significantly lower intrapartum blood loss,postpartum blood loss within 2 hours,and shorter hospital stays compared to the control group(P<0.05).Additionally,the Apgar scores at 1 minute post-birth were significantly higher in the observation group(P<0.05).The incidence of neonatal fever and jaundice was significantly lower in the observation group(P<0.05).These differences were statistically significant.Conclusion:Vaginal delivery has high clinical value for women with repeat pregnancies involving uterine scars.It reduces maternal intrapartum and postpartum blood loss,shortens hospital stays,improves neonatal Apgar scores,and decreases the incidences of neonatal fever and jaundice.This method is worthy of clinical application and promotion.展开更多
Higher-order modes of the neutron diffusion/transport equation can be used to study the temporal behavior of nuclear reactors and can be applied in modal analysis, transient analysis, and online monitoring of the reac...Higher-order modes of the neutron diffusion/transport equation can be used to study the temporal behavior of nuclear reactors and can be applied in modal analysis, transient analysis, and online monitoring of the reactor core. Both the deterministic method and the Monte Carlo(MC) method can be used to solve the higher-order modes. However, MC method, compared to the deterministic method, faces challenges in terms of computational efficiency and α mode calculation stability, whereas the deterministic method encounters issues arising from homogenization-related geometric and energy spectra adaptation.Based on the higher-order mode diffusion calculation code HARMONY, we developed a new higher-order mode calculation code, HARMONY2.0, which retains the functionality of computing λ and α higher-order modes from HARMONY1.0, but enhances the ability to treat complex geometries and arbitrary energy spectra using the MC-deterministic hybrid two-step strategy. In HARMONY2.0, the mesh homogenized multigroup constants were obtained using OpenMC in the first step,and higher-order modes were then calculated with the mesh homogenized core diffusion model using the implicitly restarted Arnoldi method(IRAM), which was also adopted in the HARMONY1.0 code. In addition, to improve the calculation efficiency, particularly in large higher-order modes, event-driven parallelization/domain decomposition methods are embedded in the HARMONY2.0 code to accelerate the inner iteration of λ∕α mode using OpenMP. Furthermore, the higher-order modes of complex geometric models, such as Hoogenboom and ATR reactors for λ mode and the MUSE-4 experiment facility for the prompt α mode, were computed using diffusion theory.展开更多
With the development of globalization,intercultural communicative competence has become one of the core qualities of modern college students.As an important platform to cultivate students’language skills and cultural...With the development of globalization,intercultural communicative competence has become one of the core qualities of modern college students.As an important platform to cultivate students’language skills and cultural literacy,the innovation of college English teaching mode is essential.Based on this,this paper mainly discusses methods to effectively cultivate students’intercultural communicative competence in college English teaching from the perspective of multimodal interactive teaching mode,hoping to provide references for improving the quality of college English teaching and students’comprehensive quality.展开更多
Due to scale effects,micromechanical resonators offer an excellent platform for investigating the intrinsic mechanisms of nonlinear dynamical phenomena and their potential applications.This review focuses on mode-coup...Due to scale effects,micromechanical resonators offer an excellent platform for investigating the intrinsic mechanisms of nonlinear dynamical phenomena and their potential applications.This review focuses on mode-coupled micromechanical resonators,highlighting the latest advancements in four key areas:internal resonance,synchronization,frequency combs,and mode localization.The origin,development,and potential applications of each of these dynamic phenomena within mode-coupled micromechanical systems are investigated,with the goal of inspiring new ideas and directions for researchers in this field.展开更多
[Objectives]To provide a reference for the promotion of appropriate row spacing configuration modes for cotton planting in the Bortala Mongol Autonomous Prefecture of Xinjiang.[Methods]Xinluzao 63 was employed as the ...[Objectives]To provide a reference for the promotion of appropriate row spacing configuration modes for cotton planting in the Bortala Mongol Autonomous Prefecture of Xinjiang.[Methods]Xinluzao 63 was employed as the research subject to examine the effects of three different configuration modes:three rows with one film,four rows with one film,and six rows with one film,on the growth and development of cotton,as well as on yield and the amount of residual film in the field.[Results]In comparison to the configuration modes of four rows with one film and six rows with one film,the development process in the row spacing configuration mode of three rows with one film was accelerated by 1-4 d.This configuration mode exhibited variability in several agronomic traits,particularly in plant height,the number of fruiting branches per plant,and the number of leaves per plant,with the observed trend indicating T3>T2>T1.Conversely,the height of the first fruiting branch node displayed an inverse trend.In terms of yield composition,no significant differences were observed in boll weight and yield among various configuration modes.However,T3 exhibited the highest boll weight at 5.68 g and a yield of 462.67 kg/667 m 2.Additionally,significant differences were noted in harvesting density and the number of bolls per plant.T3 demonstrated the lowest harvesting density at 1.11×104 plants/666.7 m 2,the highest number of bolls per plant at 8.63,and the highest boll opening rate at 97.48%.Furthermore,T3 also resulted in the least amount of agricultural film residue during the current season.[Conclusions]Among the three planting configuration modes examined,the low-density planting configuration mode consisting of three rows and one film demonstrated a significant advantage at the individual plant level.This approach yielded results comparable to those of the high density planting configuration mode while also reducing costs.Furthermore,low density planting positively influenced the cotton boll opening rate,leading to a decreased amount of residual film and promoting ecological health within the agricultural land.展开更多
A nonlinear saturation mechanism for reversed shear Alfvén eigenmode(RSAE)is proposed and analyzed,and is shown to be of relevance to typical reactor parameter region.The saturation is achieved through the genera...A nonlinear saturation mechanism for reversed shear Alfvén eigenmode(RSAE)is proposed and analyzed,and is shown to be of relevance to typical reactor parameter region.The saturation is achieved through the generation of high-frequency quasi-mode due to nonlinear coupling of two RSAEs,which is then damped due to coupling with the shear Alfvén continuum,and leads to the nonlinear saturation of the primary RSAEs.An estimation of the nonlinear damping rate is also provided.展开更多
We introduce a new kind of four-mode continuous variable entangled state in Fock space. The completeness relation and the partly nonorthonormal property of such a state are proven. The scheme to generate this state is...We introduce a new kind of four-mode continuous variable entangled state in Fock space. The completeness relation and the partly nonorthonormal property of such a state are proven. The scheme to generate this state is presented by combining a symmetrical beamsplitter, a parametric down-conversion and a polarizer. After making a single-mode quadrature amplitude measurement, the remaining three modes are kept in entanglement. And its applications are also discussed.展开更多
Near-infrared single photon sources in telecommunication bands, especially at 1550 nm, are required for long-distance quantum communication. Here a down-conversion quantum interface is implemented, where the single ph...Near-infrared single photon sources in telecommunication bands, especially at 1550 nm, are required for long-distance quantum communication. Here a down-conversion quantum interface is implemented, where the single photons emitted from single In As quantum dot at 864 nm is down converted to 1552 nm by using a fiber-coupled periodically poled lithium niobate（PPLN） waveguide and a 1.95 μmm pump laser, and the frequency conversion efficiency is ~40%. The singlephoton purity of quantum dot emission is preserved during the down-conversion process, i.e., g^（（2））（0）, only 0.22 at 1552 nm.This present technique advances the Ⅲ-Ⅴ semiconductor quantum dots as a promising platform for long-distance quantum communication.展开更多
We study the effect of waveguide thickness variations on the frequency spectrum of spontaneous parametric downconversion in the periodically-poled lithium niobate on insulator(LNOI)waveguide.We analyze several variati...We study the effect of waveguide thickness variations on the frequency spectrum of spontaneous parametric downconversion in the periodically-poled lithium niobate on insulator(LNOI)waveguide.We analyze several variation models and our simulation results show that thickness variations in several nanometers can induce distinct effects on the central peak of the spectrum,such as narrowing,broadening,and splitting.We also prove that the effects of positive and negative variations can be canceled and thus lead to a variation-robust feature and an ultra-broad bandwidth.Our study may promote the development of on-chip photon sources in the LNOI platform,as well as opens up a way to engineer photon frequency state.展开更多
By properly selecting the time-dependent unitary transformation for the linear combination of the number operators, we construct a time-dependent invariant and derive the corresponding auxiliary equations for the dege...By properly selecting the time-dependent unitary transformation for the linear combination of the number operators, we construct a time-dependent invariant and derive the corresponding auxiliary equations for the degenerate and non-degenerate coupled parametric down-conversion system with driving term. By means of this invariant and the Lewis-Riesenfeld quantum invariant theory, we obtain closed formulae of the quantum state and the evolution operator of the system. We show that the time evolution of the quantum system directly leads to production of various generalized one- and two-mode combination squeezed states, and the squeezed effect is independent of the driving term of the Hamiltonian. In some special cases, the current solution can reduce to the results of the previous works.展开更多
The decoy-state quantum key distribution protocol suggested by Adachi et al. （Phys. Rev. Lett 99 180503 （2007）） is proven to be secure and feasible with current techniques. It owns two attractive merits, i.e., its...The decoy-state quantum key distribution protocol suggested by Adachi et al. （Phys. Rev. Lett 99 180503 （2007）） is proven to be secure and feasible with current techniques. It owns two attractive merits, i.e., its longer secure transmission distance and more convenient operation design. In this paper, we first improve the protocol with the aid of local operation and two-way classical communication （2-LOCC）. After our modifications, the secure transmission distance is increased by about 20 km, which will make the protocol more practicable.展开更多
In recent years, much attention has been paid to software-defined radio （SDR） technologies for multimode wireless systems SDR can be defined as a radio communication system that uses software to modulate and demodul...In recent years, much attention has been paid to software-defined radio （SDR） technologies for multimode wireless systems SDR can be defined as a radio communication system that uses software to modulate and demodulate radio signals. This article describes concepts, theory, and design principles for SDR down-conversion and up-conversion. Design issues in SDR down-conversion are discussed, and two different architectures, super-heterodyne and direct-conversion, are proposed. Design issues in SDR up-conversion are also discussed, and trade-offs in the design of filters, mixers, NCO, DAC, and signal processing are highlighted.展开更多
基金supported by the National Natural Science Foundation of China(21075053)the"Challenge Cup"Undergraduate Extra-curriculum Academics,Science and Technology Works Competition and Student's Platform for Innovation and Entrepreneurship Training Program(201410559056)in Jinan University
文摘In this study,α-TeO2：Ho3＋/Yb3＋,α-TeO2：Eu3＋ andα-TeO2：Ho3＋/Yb3＋/Eu3＋ nanoparticles were prepared via a simple hydrothermal process. The up- and down-conversion properties of the as-prepared nanoparticles were tested at room temperature un-der a near-infrared photo source （980 nm） and UV-vis photo source, respectively.The results indicated thatα-TeO2 NPs were a kind of outstanding host material for both up- and down-conversion luminescence. Theα-TeO2：Ho3＋/Yb3＋nanoparticles showed sharp up-conversion emission at 545 and 660 nm under 980 nm excitation, ascribed to the5S2→5I8 and5F5→5I8（Ho3＋） transitions, and weaker down-conversion emission at 545 nm under 455 nm excitation, ascribed to the5S2→5I8（Ho3＋） transitions. Theα-TeO2：Eu3＋nanoparticles showed strong down-conversion emission at 592 and 615 nm under 395 nm excitation, attributed to the5D0→7F1 and 5D0→7F2 （Eu3＋） transitions. Possessing the advantages of these two luminescent materials, the as-prepared tri-doped samples ofα-TeO2：0.5Ho3＋/10Yb3＋/3Eu3＋ （mol.%）nanoparticles could successfully emit visible light via both up- and down-conversion modes.
基金supported by the National Natural Science Foundation of China [grant number 42088101]。
文摘During the boreal summer,intraseasonal oscillations exhibit significant interannual variations in intensity over two key regions:the central-western equatorial Pacific(5°S-5°N,150°E-150°W)and the subtropical Northwestern Pacific(10°-20°N,130°E-175°W).The former is well-documented and considered to be influenced by the ENSO,while the latter has received comparatively less attention and is likely influenced by the Pacific Meridional Mode(PMM),as suggested by partial correlation analysis results.To elucidate the physical processes responsible for the enhanced(weakened)intraseasonal convection over the subtropical northwestern Pacific during warm(cold)PMM years,the authors employed a moisture budget analysis.The findings reveal that during warm PMM years,there is an increase in summer-mean moisture over the subtropical northwestern Pacific.This increase interacts with intensified vertical motion perturbations in the region,leading to greater vertical moisture advection in the lower troposphere and consequently resulting in convective instability.Such a process is pivotal in amplifying intraseasonal convection anomalies.The observational findings were further verified by model experiments forced by PMM-like sea surface temperature patterns.
文摘Objective: To develop a best-evidence-based optimal nutrition management plan for patients with chronic heart failure, apply it in clinical practice, and evaluate its effectiveness. Methods: Use the KTA knowledge translation model to guide evidence-based practice in nutrition management, and compare the nutritional status, cardiac function status, quality of life, and quality review indicators of chronic heart failure patients before and after the application of evidence. Results: After the application of evidence, the nutritional status indicators (MNA-SF score, albumin, hemoglobin) of two groups of heart failure patients significantly increased compared to before the application of evidence, with statistically significant differences (p Conclusion: The KTA knowledge translation model provides methodological guidance for the implementation of evidence-based practice for heart failure patients. This evidence-based practice project is beneficial for improving the outcomes of malnutrition in chronic heart failure patients and is conducive to standardizing nursing pathways, thereby promoting the improvement of nursing quality.
文摘In order to enhance the control performance of piezo-positioning system,the influence of hysteresis characteristics and its compensation method are studied.Hammerstein model is used to represent the dynamic hysteresis nonlinear characteristics of piezo-positioning actuator.The static nonlinear part and dynamic linear part of the Hammerstein model are represented by models obtained through the Prandtl-Ishlinskii(PI)model and Hankel matrix system identification method,respectively.This model demonstrates good generalization capability for typical input frequencies below 200 Hz.A sliding mode inverse compensation tracking control strategy based on P-I inverse model and integral augmentation is proposed.Experimental results show that compared with PID inverse compensation control and sliding mode control without inverse compensation,the sliding mode inverse compensation control has a more ideal step response and no overshoot,moreover,the settling time is only 6.2 ms.In the frequency domain,the system closed-loop tracking bandwidth reaches 119.9 Hz,and the disturbance rejection bandwidth reaches 86.2 Hz.The proposed control strategy can effectively compensate the hysteresis nonlinearity,and improve the tracking accuracy and antidisturbance capability of piezo-positioning system.
基金Project supported by the National Natural Science Foundation of China(Grant No.42230207)the Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)(Grant No.G1323523064)。
文摘We apply the WKB approximation method,matrix method,and finite difference method to study the gravitational quasi-normal modes of charged spherically symmetric black holes surrounded by quintessence fluid in Rastall gravity.By comparing the spherically symmetric spacetime metric of charged black holes surrounded by quintessence fluid in Rastall gravity with that of general relativity,we can find that the modifications to general relativity in this modified gravity theory can be described by parameters such asλ,Q,and C_(a),etc.In four-dimensional spacetime,we investigate the impact of charge Q and parameter C_(a) on the gravitational quasi-normal modes of charged black holes surrounded by quintessence field in Rastall gravity.The aim is to search for observational evidence of such black holes in astrophysical observations and,consequently,test the validity of Rastall theory.In five-dimensional(5D)spacetime,we study the impact of the parameter C_(a) on the gravitational quasi-normal modes of Rastall black holes surrounded by quintessence field and summarize the corresponding variation patterns.
文摘In the process of cultural and tourism project construction,intelligent construction technology has gradually shown strong advantages.The effective application of this technology not only greatly improves the construction efficiency and quality of cultural and tourism projects,but also effectively controls construction costs,laying a solid foundation for the green,low-carbon,and sustainable development of the cultural and tourism industry.The article analyzes the current situation of cultural and tourism project construction,proposes the advantages of intelligent construction and its application in the construction mode of cultural and tourism projects,aiming to provide reliable guidance for the sustainable development of cultural and tourism projects.
文摘Objective:To investigate the delivery modes of women with repeat pregnancies involving uterine scars and their effects on both mothers and neonates.Methods:A study was conducted on 100 patients treated at Shenzhen Maternity and Child Healthcare Hospital from July 2023 to July 2024.The participants were divided into a control group and an observation group,with 50 cases in each.The division was based on the indications for prior cesarean section,cervical maturity,postpartum complications,and thickness of the cesarean scar.The control group underwent cesarean delivery,while the observation group experienced vaginal delivery.The two groups were compared in terms of intrapartum blood loss,postpartum blood loss within 2 hours,length of hospital stay,Apgar scores at 1-minute post-birth,and incidences of neonatal fever and jaundice.Results:The observation group had significantly lower intrapartum blood loss,postpartum blood loss within 2 hours,and shorter hospital stays compared to the control group(P<0.05).Additionally,the Apgar scores at 1 minute post-birth were significantly higher in the observation group(P<0.05).The incidence of neonatal fever and jaundice was significantly lower in the observation group(P<0.05).These differences were statistically significant.Conclusion:Vaginal delivery has high clinical value for women with repeat pregnancies involving uterine scars.It reduces maternal intrapartum and postpartum blood loss,shortens hospital stays,improves neonatal Apgar scores,and decreases the incidences of neonatal fever and jaundice.This method is worthy of clinical application and promotion.
基金supported by the National Natural Science Foundation of China(No.U2267207)Science and Technology on Reactor System Design Technology Laboratory(No.KFKT-05-FWHTWU-2023004).
文摘Higher-order modes of the neutron diffusion/transport equation can be used to study the temporal behavior of nuclear reactors and can be applied in modal analysis, transient analysis, and online monitoring of the reactor core. Both the deterministic method and the Monte Carlo(MC) method can be used to solve the higher-order modes. However, MC method, compared to the deterministic method, faces challenges in terms of computational efficiency and α mode calculation stability, whereas the deterministic method encounters issues arising from homogenization-related geometric and energy spectra adaptation.Based on the higher-order mode diffusion calculation code HARMONY, we developed a new higher-order mode calculation code, HARMONY2.0, which retains the functionality of computing λ and α higher-order modes from HARMONY1.0, but enhances the ability to treat complex geometries and arbitrary energy spectra using the MC-deterministic hybrid two-step strategy. In HARMONY2.0, the mesh homogenized multigroup constants were obtained using OpenMC in the first step,and higher-order modes were then calculated with the mesh homogenized core diffusion model using the implicitly restarted Arnoldi method(IRAM), which was also adopted in the HARMONY1.0 code. In addition, to improve the calculation efficiency, particularly in large higher-order modes, event-driven parallelization/domain decomposition methods are embedded in the HARMONY2.0 code to accelerate the inner iteration of λ∕α mode using OpenMP. Furthermore, the higher-order modes of complex geometric models, such as Hoogenboom and ATR reactors for λ mode and the MUSE-4 experiment facility for the prompt α mode, were computed using diffusion theory.
文摘With the development of globalization,intercultural communicative competence has become one of the core qualities of modern college students.As an important platform to cultivate students’language skills and cultural literacy,the innovation of college English teaching mode is essential.Based on this,this paper mainly discusses methods to effectively cultivate students’intercultural communicative competence in college English teaching from the perspective of multimodal interactive teaching mode,hoping to provide references for improving the quality of college English teaching and students’comprehensive quality.
基金supported by the National Key Research and Development Program of China(No.2022YFB3203600)the National Natural Science Foundation of China(Nos.12202355,12132013,and 12172323)the Zhejiang Provincial Natural Science Foundation of China(No.LZ22A020003)。
文摘Due to scale effects,micromechanical resonators offer an excellent platform for investigating the intrinsic mechanisms of nonlinear dynamical phenomena and their potential applications.This review focuses on mode-coupled micromechanical resonators,highlighting the latest advancements in four key areas:internal resonance,synchronization,frequency combs,and mode localization.The origin,development,and potential applications of each of these dynamic phenomena within mode-coupled micromechanical systems are investigated,with the goal of inspiring new ideas and directions for researchers in this field.
基金Supported by China Agriculture(Cotton)Research System(CARS-15-46)Intellectual Aid Xinjiang Innovation and Expansion Talent Program of Xinjiang Uygur Autonomous Region(2024500207).
文摘[Objectives]To provide a reference for the promotion of appropriate row spacing configuration modes for cotton planting in the Bortala Mongol Autonomous Prefecture of Xinjiang.[Methods]Xinluzao 63 was employed as the research subject to examine the effects of three different configuration modes:three rows with one film,four rows with one film,and six rows with one film,on the growth and development of cotton,as well as on yield and the amount of residual film in the field.[Results]In comparison to the configuration modes of four rows with one film and six rows with one film,the development process in the row spacing configuration mode of three rows with one film was accelerated by 1-4 d.This configuration mode exhibited variability in several agronomic traits,particularly in plant height,the number of fruiting branches per plant,and the number of leaves per plant,with the observed trend indicating T3>T2>T1.Conversely,the height of the first fruiting branch node displayed an inverse trend.In terms of yield composition,no significant differences were observed in boll weight and yield among various configuration modes.However,T3 exhibited the highest boll weight at 5.68 g and a yield of 462.67 kg/667 m 2.Additionally,significant differences were noted in harvesting density and the number of bolls per plant.T3 demonstrated the lowest harvesting density at 1.11×104 plants/666.7 m 2,the highest number of bolls per plant at 8.63,and the highest boll opening rate at 97.48%.Furthermore,T3 also resulted in the least amount of agricultural film residue during the current season.[Conclusions]Among the three planting configuration modes examined,the low-density planting configuration mode consisting of three rows and one film demonstrated a significant advantage at the individual plant level.This approach yielded results comparable to those of the high density planting configuration mode while also reducing costs.Furthermore,low density planting positively influenced the cotton boll opening rate,leading to a decreased amount of residual film and promoting ecological health within the agricultural land.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB0790000)the Collaborative Innovation Program of Hefei Science Center,CAS(No.2022HSC-CIP008)National Natural Science Foundation of China(Nos.12275236 and 12261131622)。
文摘A nonlinear saturation mechanism for reversed shear Alfvén eigenmode(RSAE)is proposed and analyzed,and is shown to be of relevance to typical reactor parameter region.The saturation is achieved through the generation of high-frequency quasi-mode due to nonlinear coupling of two RSAEs,which is then damped due to coupling with the shear Alfvén continuum,and leads to the nonlinear saturation of the primary RSAEs.An estimation of the nonlinear damping rate is also provided.
基金supported by the Natural Science Foundation of Jiangxi Province,China (Grant No 2007GZW0171)the Foundation of Education Department of Jiangxi Province,China (Grant No [2007] 136)
文摘We introduce a new kind of four-mode continuous variable entangled state in Fock space. The completeness relation and the partly nonorthonormal property of such a state are proven. The scheme to generate this state is presented by combining a symmetrical beamsplitter, a parametric down-conversion and a polarizer. After making a single-mode quadrature amplitude measurement, the remaining three modes are kept in entanglement. And its applications are also discussed.
基金Project supported by the National Key Technologies R&D Program of China(Grant No.2018YFA0306101)the Scientific Instrument Developing Project of Chinese Academy of Sciences(Grant No.YJKYYQ20170032)the National Natural Science Foundation of China(Grant No.61505196)
文摘Near-infrared single photon sources in telecommunication bands, especially at 1550 nm, are required for long-distance quantum communication. Here a down-conversion quantum interface is implemented, where the single photons emitted from single In As quantum dot at 864 nm is down converted to 1552 nm by using a fiber-coupled periodically poled lithium niobate（PPLN） waveguide and a 1.95 μmm pump laser, and the frequency conversion efficiency is ~40%. The singlephoton purity of quantum dot emission is preserved during the down-conversion process, i.e., g^（（2））（0）, only 0.22 at 1552 nm.This present technique advances the Ⅲ-Ⅴ semiconductor quantum dots as a promising platform for long-distance quantum communication.
基金Project supported by the National Key R&D Program of China(Grant No.2019YFA0705000)Leading-edge Technology Program of Jiangsu Natural Science Foundation,China(Grant No.BK20192001)the National Natural Science Foundation of China(Grant Nos.51890861,11690031,11974178,and 11627810).
文摘We study the effect of waveguide thickness variations on the frequency spectrum of spontaneous parametric downconversion in the periodically-poled lithium niobate on insulator(LNOI)waveguide.We analyze several variation models and our simulation results show that thickness variations in several nanometers can induce distinct effects on the central peak of the spectrum,such as narrowing,broadening,and splitting.We also prove that the effects of positive and negative variations can be canceled and thus lead to a variation-robust feature and an ultra-broad bandwidth.Our study may promote the development of on-chip photon sources in the LNOI platform,as well as opens up a way to engineer photon frequency state.
基金supported by the National Natural Science Foundation of China under Grant Nos.40674076 and 40474064the Hunan Natural Science Foundation of China under Grant No.07JJ3123the Scientific Research Fund of Hunan Provincial Education Department under Grant Nos.06C163,05B023,and 06B004
文摘By properly selecting the time-dependent unitary transformation for the linear combination of the number operators, we construct a time-dependent invariant and derive the corresponding auxiliary equations for the degenerate and non-degenerate coupled parametric down-conversion system with driving term. By means of this invariant and the Lewis-Riesenfeld quantum invariant theory, we obtain closed formulae of the quantum state and the evolution operator of the system. We show that the time evolution of the quantum system directly leads to production of various generalized one- and two-mode combination squeezed states, and the squeezed effect is independent of the driving term of the Hamiltonian. In some special cases, the current solution can reduce to the results of the previous works.
基金supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 10905028/A050104)the Natural Science Foundation of Henan Province,China (Grant No. 092300410188)+1 种基金the Science Foundation of Hennan Provincial Education Department (Grant No. 2010A140010)Youth Fund of Luoyang Normal College
文摘The decoy-state quantum key distribution protocol suggested by Adachi et al. （Phys. Rev. Lett 99 180503 （2007）） is proven to be secure and feasible with current techniques. It owns two attractive merits, i.e., its longer secure transmission distance and more convenient operation design. In this paper, we first improve the protocol with the aid of local operation and two-way classical communication （2-LOCC）. After our modifications, the secure transmission distance is increased by about 20 km, which will make the protocol more practicable.
文摘In recent years, much attention has been paid to software-defined radio （SDR） technologies for multimode wireless systems SDR can be defined as a radio communication system that uses software to modulate and demodulate radio signals. This article describes concepts, theory, and design principles for SDR down-conversion and up-conversion. Design issues in SDR down-conversion are discussed, and two different architectures, super-heterodyne and direct-conversion, are proposed. Design issues in SDR up-conversion are also discussed, and trade-offs in the design of filters, mixers, NCO, DAC, and signal processing are highlighted.
