The use of agricultural straw for algal bloom control has been studied for more than 30 years.In this article,we have reviewed the promising potentials of using agricultural straw as source of anti-algal agents,includ...The use of agricultural straw for algal bloom control has been studied for more than 30 years.In this article,we have reviewed the promising potentials of using agricultural straw as source of anti-algal agents,including the effectiveness of each major straw type so far used in this regard,and the investigated algal species.Various pre-treatment methods have also been widely reviewed.Significant progress has been made in natural product chemistry and molecular biology with regards to agricultural straw,especially in relation to the extraction of antialgal allelochemicals,degradation processes of agricultural straws and the mechanisms through which these inhibitions occur.The development of biotechnologies using agricultural straw to successfully inhibit growth of bloom forming algae has been generally accepted as environmentally friendly.The current research status and that of the future should include isolation and discovery of antialgal allelochemicals,development of models that would illustrate the sequence of physiologic events that match the species-specific inhibitor phenomenon,and products fit in the field applications.展开更多
Linear switch reluctance machine(LSRM)has been tried to act as an alternative generator for direct drive linear wave energy converter(WEC).Many researchers have proposed new topologies of LSRM to improve the power den...Linear switch reluctance machine(LSRM)has been tried to act as an alternative generator for direct drive linear wave energy converter(WEC).Many researchers have proposed new topologies of LSRM to improve the power density,efficiency and reliability.However,the control methods for LSRM applied in direct drive WEC have been paid little attention,especially control methods considering the wave energy generator operating characteristics.In this paper,according to the generator control requirements of the direct drive WEC,force control algorithm for LSRM operating in four quadrants without a speed closed loop is put forward.The force ripple of LSRM is suppressed using force sharing function method.The four-quadrant control is easy to realize requiring only phase currents information.Simulation results validate the proposed method and indicate that LSRM is able to be used as the generator for direct drive WEC.展开更多
Silicon photonics has attracted a great deal of interest for integrated photonics systems due to its large-scale electronics-photonics integration on a chip by leveraging the fabrication process of the complementary-m...Silicon photonics has attracted a great deal of interest for integrated photonics systems due to its large-scale electronics-photonics integration on a chip by leveraging the fabrication process of the complementary-metal-oxide semiconductor(CMOS)foundries[1−5].Germanium-on-silicon(Ge-on-Si)waveguide photodetector(PD)is an indispensable building block of silicon photonics technology which requires high sensitivity.展开更多
Parity‐time(PT)symmetry breaking offers mode selection capability for facilitating single‐mode oscillation in the optoelectronic oscillator(OEO)loop.However,most OEO implementations depend on discrete devices,which ...Parity‐time(PT)symmetry breaking offers mode selection capability for facilitating single‐mode oscillation in the optoelectronic oscillator(OEO)loop.However,most OEO implementations depend on discrete devices,which impedes proliferation due to size,weight,power consumption,and cost.In this work,we propose and experimentally demonstrate an on-chip tunable PT‐symmetric OEO.A tunable microwave photonic filter,a PT‐symmetric mode‐selective architecture,and two photodetectors are integrated on a silicon‐on‐insulator chip.By exploiting an on‐chip Mach–Zehnder interferometer to match the gain and loss of two mutually coupled optoelectronic loops,single‐mode oscillation can be obtained.In the experiment,the oscillation frequency of the on-chip tunable PT‐symmetric OEO can be tuned from 0 to 20 GHz.To emulate the integrated case,the OEO loop length is minimized,and no extra-long fiber is used in the experiment.When the oscillation frequency is 13.67 GHz,the single‐sideband phase noise at 10-kHz offset frequency is−80.96 dBc∕Hz and the side mode suppression ratio is 46 dB.The proposed on-chip tunable PT‐symmetric OEO significantly reduces the footprint of the system and enhances mode selection.展开更多
As the refiner or modifier, the master alloys containing high concentration phosphor are widely used in preparing eutectic or hypereutectic Al-Si alloys. To study the effect of phosphor addition on the eutectic solidi...As the refiner or modifier, the master alloys containing high concentration phosphor are widely used in preparing eutectic or hypereutectic Al-Si alloys. To study the effect of phosphor addition on the eutectic solidification and microstructure of the Al-13%Si alloy, an investigation has been undertaken by means of thermal analysis and micro/macro-structure observation. Results indicate that addition of phosphor in near eutectic Al-Si alloy promotes the nucleation of eutectic but has little refinement impact on primary Si particles as expected. Conversely, both primary Si particles and eutectic Si flakes become slightly coarser in P-rich alloys. The coarsening of eutectic Si flakes ties closely to the increased eutectic growth temperature with phosphor addition. The eutectic solidification of the alloy proceeds from the near mold zone towards the center, and it is also found that a few independent nucleation regions emerge in liquid at the solidification front due to the addition of phosphor.展开更多
Under cooling rates of 2 ℃/s and 10℃/s, the influences of B content on the microstructure of near eutectic Al-13.0wt%Si alloy have been investigated. Results showed that the addition of boron resulted in refinement ...Under cooling rates of 2 ℃/s and 10℃/s, the influences of B content on the microstructure of near eutectic Al-13.0wt%Si alloy have been investigated. Results showed that the addition of boron resulted in refinement of eutectic grains, and to some extent, had an inhibiting effect on precipitation of the primary phases, and the refining and inhibiting effects are much more obvious at higher cooling rate. When B was not added, higher cooling rate promoted the α-Al dendrites formation. At lower cooling rate, the addition of B did not cause the so called ＂columnar to equiaxed transition （CET）＂, however, at higher cooling rate, this transition was obvious. After the addition of B, the nucleation temperature TN ascended and nucleation mode changed from nucleation mode of from wall towards centre （without B addition） to a nucleation mode that the eutectic nucleated evenly throughout whole sample （with B added）. It can be concluded that the addition of B offers a large amount of nuclei for eutectic solidification, as a result, the eutectic grains was refined. Higher cooling rate will lead to more nuclei, so the effects on the refinement of eutectic grains and on suppression of primary phases are increased.展开更多
CURRENTLY,new technologies and applications are presenting both new challenges and new opportunities to the field of electric machines and motors.The continual dedicated effort of researchers is required to achieve th...CURRENTLY,new technologies and applications are presenting both new challenges and new opportunities to the field of electric machines and motors.The continual dedicated effort of researchers is required to achieve the high-performance and high-reliability of electric machines while ensuring their cost-effectiveness.In motor design,with the advancements of optimization theory and technology,increasingly effective methods have been developed for the design of motors.展开更多
基金financially supported by the Major Science and Technology Program forWater Pollution Control and Treatment(2018ZX07208-009)the National Natural Science Foundation of China(21677122 and 21876148)+4 种基金the open fund of the Key Laboratory of Marine Eco-monitoring and Remediation Technology,Ministry of Natural Resources(MATHAB201809)the open fund of the Key Laboratory of Marine Ecosystem Dynamics,Second Institute of Oceanography,Ministry of Natural Resources(LMEB201709)Key Projects of Philosophy and Social Sciences Research,Ministry of Education(18JZD059)Fundamental Research Funds for the Central Universities(2019QNA4051)the China Scholarship Council(201806325035).
文摘The use of agricultural straw for algal bloom control has been studied for more than 30 years.In this article,we have reviewed the promising potentials of using agricultural straw as source of anti-algal agents,including the effectiveness of each major straw type so far used in this regard,and the investigated algal species.Various pre-treatment methods have also been widely reviewed.Significant progress has been made in natural product chemistry and molecular biology with regards to agricultural straw,especially in relation to the extraction of antialgal allelochemicals,degradation processes of agricultural straws and the mechanisms through which these inhibitions occur.The development of biotechnologies using agricultural straw to successfully inhibit growth of bloom forming algae has been generally accepted as environmentally friendly.The current research status and that of the future should include isolation and discovery of antialgal allelochemicals,development of models that would illustrate the sequence of physiologic events that match the species-specific inhibitor phenomenon,and products fit in the field applications.
基金This work was supported in part by the National Natural Science Foundation of China under Grant U1806224,61733010in part by the Guangdong Key Research and Development Program under Grant 2019B090917001.
文摘Linear switch reluctance machine(LSRM)has been tried to act as an alternative generator for direct drive linear wave energy converter(WEC).Many researchers have proposed new topologies of LSRM to improve the power density,efficiency and reliability.However,the control methods for LSRM applied in direct drive WEC have been paid little attention,especially control methods considering the wave energy generator operating characteristics.In this paper,according to the generator control requirements of the direct drive WEC,force control algorithm for LSRM operating in four quadrants without a speed closed loop is put forward.The force ripple of LSRM is suppressed using force sharing function method.The four-quadrant control is easy to realize requiring only phase currents information.Simulation results validate the proposed method and indicate that LSRM is able to be used as the generator for direct drive WEC.
基金This work was supported by National Key Research and Development Program of China(2019YFB2205201,2019YFB2205203)Hubei Technological Innovation Project(2019AAA054).
文摘Silicon photonics has attracted a great deal of interest for integrated photonics systems due to its large-scale electronics-photonics integration on a chip by leveraging the fabrication process of the complementary-metal-oxide semiconductor(CMOS)foundries[1−5].Germanium-on-silicon(Ge-on-Si)waveguide photodetector(PD)is an indispensable building block of silicon photonics technology which requires high sensitivity.
基金supported by the National Key Research and Development Program of China(Grant No.2018YFA0704403)the National Natural Science Foundation of China(Grant No.61975249)the Program for HUST Academic Frontier Youth Team(Grant No.2018QYTD08).
文摘Parity‐time(PT)symmetry breaking offers mode selection capability for facilitating single‐mode oscillation in the optoelectronic oscillator(OEO)loop.However,most OEO implementations depend on discrete devices,which impedes proliferation due to size,weight,power consumption,and cost.In this work,we propose and experimentally demonstrate an on-chip tunable PT‐symmetric OEO.A tunable microwave photonic filter,a PT‐symmetric mode‐selective architecture,and two photodetectors are integrated on a silicon‐on‐insulator chip.By exploiting an on‐chip Mach–Zehnder interferometer to match the gain and loss of two mutually coupled optoelectronic loops,single‐mode oscillation can be obtained.In the experiment,the oscillation frequency of the on-chip tunable PT‐symmetric OEO can be tuned from 0 to 20 GHz.To emulate the integrated case,the OEO loop length is minimized,and no extra-long fiber is used in the experiment.When the oscillation frequency is 13.67 GHz,the single‐sideband phase noise at 10-kHz offset frequency is−80.96 dBc∕Hz and the side mode suppression ratio is 46 dB.The proposed on-chip tunable PT‐symmetric OEO significantly reduces the footprint of the system and enhances mode selection.
基金financially supported by the National Natural Science Foundation of China under grant No. 50771031
文摘As the refiner or modifier, the master alloys containing high concentration phosphor are widely used in preparing eutectic or hypereutectic Al-Si alloys. To study the effect of phosphor addition on the eutectic solidification and microstructure of the Al-13%Si alloy, an investigation has been undertaken by means of thermal analysis and micro/macro-structure observation. Results indicate that addition of phosphor in near eutectic Al-Si alloy promotes the nucleation of eutectic but has little refinement impact on primary Si particles as expected. Conversely, both primary Si particles and eutectic Si flakes become slightly coarser in P-rich alloys. The coarsening of eutectic Si flakes ties closely to the increased eutectic growth temperature with phosphor addition. The eutectic solidification of the alloy proceeds from the near mold zone towards the center, and it is also found that a few independent nucleation regions emerge in liquid at the solidification front due to the addition of phosphor.
基金the natural science fund of Jiangsu province (BK2004069)beforehand research fund of Southeast University (XJ0612238) .
文摘Under cooling rates of 2 ℃/s and 10℃/s, the influences of B content on the microstructure of near eutectic Al-13.0wt%Si alloy have been investigated. Results showed that the addition of boron resulted in refinement of eutectic grains, and to some extent, had an inhibiting effect on precipitation of the primary phases, and the refining and inhibiting effects are much more obvious at higher cooling rate. When B was not added, higher cooling rate promoted the α-Al dendrites formation. At lower cooling rate, the addition of B did not cause the so called ＂columnar to equiaxed transition （CET）＂, however, at higher cooling rate, this transition was obvious. After the addition of B, the nucleation temperature TN ascended and nucleation mode changed from nucleation mode of from wall towards centre （without B addition） to a nucleation mode that the eutectic nucleated evenly throughout whole sample （with B added）. It can be concluded that the addition of B offers a large amount of nuclei for eutectic solidification, as a result, the eutectic grains was refined. Higher cooling rate will lead to more nuclei, so the effects on the refinement of eutectic grains and on suppression of primary phases are increased.
文摘CURRENTLY,new technologies and applications are presenting both new challenges and new opportunities to the field of electric machines and motors.The continual dedicated effort of researchers is required to achieve the high-performance and high-reliability of electric machines while ensuring their cost-effectiveness.In motor design,with the advancements of optimization theory and technology,increasingly effective methods have been developed for the design of motors.
