In this paper, we investigate a metamaterial formed by a planar array of a metallic L-shaped structure and a cut wire(CW), which behaves as an analogue of the electromagnetically induced transparency(EIT). The double ...In this paper, we investigate a metamaterial formed by a planar array of a metallic L-shaped structure and a cut wire(CW), which behaves as an analogue of the electromagnetically induced transparency(EIT). The double transmission peaks are formed by the destructive interference of two bright-modes and a quasi-dark mode. The two bright-modes are respectively excited by the L-shaped structure and CW. The unit structure itself performs a quasi-dark mode. The group refractive indexes are over 20 in the first transmission peak, and 117 in the second transmission peak, thus offering potential applications in slow light devices. Finally, all the above characteristics are achieved in just one simple unit cell.展开更多
It is the traditional belief that sound transmission from water to the air is very weak due to a large contrast between air and water impedances. Recently, the enhanced sound transmission and anomalous transparency of...It is the traditional belief that sound transmission from water to the air is very weak due to a large contrast between air and water impedances. Recently, the enhanced sound transmission and anomalous transparency of air-water interface have been introduced. Anomalous transparency of air-water interface states that the sound generated by a submerged shallow depth monopole point source localized at depths less than 1/10 sound wavelength, can be transmitted into the air with omni-directional pattern. The generated sound has 35 times higher power compared to the classical ray theory prediction. In this paper, sound transmission through air-water interface for a localized underwater shallow depth source is examined. To accomplish this, two-phase coupled Helmholtz wave equations in two-phase media of air-water are solved by the commercial finite element based COMSOL Multiphysics software. Ratios of pressure amplitudes of different sound sources in two different underwater and air coordinates are computed and analyzed against non-dimensional ratio of the source depth （D） to the sound wavelength （λ）. The obtained results are compared with the experimental data and good agreement is displayed.展开更多
The transmittance of the thin A1 film with sheet resistance less than 10Ω/□ is able to be over 50％ . In this paper the effects of A1 film thickness on its properties have been investigated.
In this manuscript,we proposed the concept of a terrestrial transparent energy receiving system for a Space Solar Power Station(SSPS),aiming at solving the problems of environmental destruction and the waste of land r...In this manuscript,we proposed the concept of a terrestrial transparent energy receiving system for a Space Solar Power Station(SSPS),aiming at solving the problems of environmental destruction and the waste of land resources caused by the construction of large area rectenna arrays at the traditional terrestrial receiving system.We also fabricated a demonstration model of the new system.The system’s energy receiving and converting device consists of many rectenna arrays that are flexible,transparent,and matching network eliminated to harvest the microwave energy averaging about 80 mW/m2 on the ground from the Solar Power Satellite(SPS).The rectenna unit of the system operates at 2.45 GHz,and the measured RF to DC conversion efficiency reaches 20%at−10 dBm and up to 64.65%at 6.8 dBm.As the rectenna array of the system has the advantages of both microwave energy harvesting and light transmittance,conventional solar panels can be placed underneath to collect sunlight and convert it into electricity.It is also feasible to build‘‘self-powered’’smart agricultural greenhouses for vegetable cultivation underneath so that the collected energy can be utilized locally to avoid the waste caused by long-distance transmission.The proposed system is of great significance to the research on environmental protection and efficient utilization of land resources at the terrestrial energy receiving system of the Space Solar Power Station.展开更多
Background Transparent dressings are commonly used to cover central venous catheter sites. However, it has been suggested that they might not allow adequate moisture vapor transmission, resulting in local moistness th...Background Transparent dressings are commonly used to cover central venous catheter sites. However, it has been suggested that they might not allow adequate moisture vapor transmission, resulting in local moistness that promotes bacterial growth. We compared the moisture vapor transmission rates （MVTRs） of different, currently used transparent and traditional gauze dressings. We aimed to determine the MVTRs at different temperatures and humidities. Methods The dressings were used to seal 50-ml plastic centrifuge tubes containing 20 ml deionized water： Tubes in group 1 were covered with 12 layers of ordinary gauze, group 2 with IV3000, group 3 with OPSITE FLEXlGRID, group 4 with 3M HP Tegaderm, and group 5 with 3M Tegaderm. The tubes were placed upright in an artificial climate cabinet, so that the dressings were not touching the water, in order to simulate the conditions of medical dressings in contact with the skin. The average MVTRs were determined under different conditions. MVTRs were also determined with tubes from groups 2-5 laid on their sides, allowing the dressings to touch the water, so simulating contact of the dressings with sweating skin, or wounded skin with exudates. We also calculated the dressings＇ self-reactive abilities by comparing their MVTRs in contact with the water surface with those when not in contact with the water surface. Results Group 1 demonstrated the highest MVTR, followed by groups 2, 4, 3 and 5 under conditions simulating contact of the dressings with normal skin at the following temperatures and humidities： 20℃/30%, 20℃/60%, 20℃/90%, 37℃/30%, 37℃/60% and 37℃/90%. When the relative humidity （RH） increased, the MVTRs decreased. The MVTRs differed significantly among different dressings and RHs： At high temperature （37℃） and high humidity （90%）, the MVTR of the transparent dressings in group 2 was higher than that of group 1 （P 〈0.01）. The reactive MVTR was highest in group 2 （10.2-16.3 times 〉MVTR） while that of group 4 was second highest （2.6-9.6 times 〉MVTR）. Conclusions RH and temperature had significant effects on the MVTRs of different dressings. The IV3000 transparent dressing used in group 2 was as effective as ordinary gauze. These results suggest that increased infection rates due to low MVTRs might not be a problem. The clinical implications of these observations for catheter-related infections need to be further investigated in multicenter studies.展开更多
The coupled resonator-induced transparency （CRIT） phenomenon, which is analogous to electromagnetically induced transparency in atomic systems, can occur in an original integrated optical resonator system due to the...The coupled resonator-induced transparency （CRIT） phenomenon, which is analogous to electromagnetically induced transparency in atomic systems, can occur in an original integrated optical resonator system due to the coherent interference of the coupled optical resonators. The system was composed of three ring resonators on silicon, each with the same cavity size, and the optical coupling to the input and output ports was achieved using grating with a power coupling efficiency of 36%. A CRIT resonance whose spectrum shows a narrow transparency peak with a low group velocity was demonstrated. The quality factor of the ring resonator can attain a value up to 6x 104, and the harmonic wavelength can be controlled by adjusting the temperature. The through and drop transmission spectra of the resonator are reconciled well with each other and also consistent well with the theoretical analysis.展开更多
A high-performance noncoherent transmission scheme is proposed in the broadcasting phase of a twoway relay transmission(TWRT),where multiple-symbol differential detection(MSDD)is performed because of its excellent det...A high-performance noncoherent transmission scheme is proposed in the broadcasting phase of a twoway relay transmission(TWRT),where multiple-symbol differential detection(MSDD)is performed because of its excellent detection performance with no channel estimation.Specifically,the generalized likelihood ratio test aided MSDD(GLRT-MSDD)is developed for the down-link.Furthermore,GLRT-MSDD is reformulated and a semidefinite relaxation aided MSDD(SDR-MSDD)is proposed.The reformulation of GLRT-MSDD to SDR-MSDD is desirable owing to its reduced complexity.Performance analysis and the simulations validate that the proposed SDR-MSDD provides the bit-error-rate performance close to that of GLRT-MSDD with reasonable complexity in TWRT.展开更多
基金supported by the Chinese Specialized Research Fund for the Doctoral Program of Higher Education,China(Grant No.20123218110017)the National Natural Science Foundation of China(Grant Nos.61307052 and 61471368)+1 种基金the Foundation of Aeronautical Science,China(Grant No.20121852030)the Fundamental Research Funds for the Central Universities(Grant No.kfjj20150407)
文摘In this paper, we investigate a metamaterial formed by a planar array of a metallic L-shaped structure and a cut wire(CW), which behaves as an analogue of the electromagnetically induced transparency(EIT). The double transmission peaks are formed by the destructive interference of two bright-modes and a quasi-dark mode. The two bright-modes are respectively excited by the L-shaped structure and CW. The unit structure itself performs a quasi-dark mode. The group refractive indexes are over 20 in the first transmission peak, and 117 in the second transmission peak, thus offering potential applications in slow light devices. Finally, all the above characteristics are achieved in just one simple unit cell.
文摘It is the traditional belief that sound transmission from water to the air is very weak due to a large contrast between air and water impedances. Recently, the enhanced sound transmission and anomalous transparency of air-water interface have been introduced. Anomalous transparency of air-water interface states that the sound generated by a submerged shallow depth monopole point source localized at depths less than 1/10 sound wavelength, can be transmitted into the air with omni-directional pattern. The generated sound has 35 times higher power compared to the classical ray theory prediction. In this paper, sound transmission through air-water interface for a localized underwater shallow depth source is examined. To accomplish this, two-phase coupled Helmholtz wave equations in two-phase media of air-water are solved by the commercial finite element based COMSOL Multiphysics software. Ratios of pressure amplitudes of different sound sources in two different underwater and air coordinates are computed and analyzed against non-dimensional ratio of the source depth （D） to the sound wavelength （λ）. The obtained results are compared with the experimental data and good agreement is displayed.
文摘The transmittance of the thin A1 film with sheet resistance less than 10Ω/□ is able to be over 50％ . In this paper the effects of A1 film thickness on its properties have been investigated.
基金supported in part by the NSFC U22A2015,62071316Sichuan Science and Technology Program under Grant 2024YFHZ0282.
文摘In this manuscript,we proposed the concept of a terrestrial transparent energy receiving system for a Space Solar Power Station(SSPS),aiming at solving the problems of environmental destruction and the waste of land resources caused by the construction of large area rectenna arrays at the traditional terrestrial receiving system.We also fabricated a demonstration model of the new system.The system’s energy receiving and converting device consists of many rectenna arrays that are flexible,transparent,and matching network eliminated to harvest the microwave energy averaging about 80 mW/m2 on the ground from the Solar Power Satellite(SPS).The rectenna unit of the system operates at 2.45 GHz,and the measured RF to DC conversion efficiency reaches 20%at−10 dBm and up to 64.65%at 6.8 dBm.As the rectenna array of the system has the advantages of both microwave energy harvesting and light transmittance,conventional solar panels can be placed underneath to collect sunlight and convert it into electricity.It is also feasible to build‘‘self-powered’’smart agricultural greenhouses for vegetable cultivation underneath so that the collected energy can be utilized locally to avoid the waste caused by long-distance transmission.The proposed system is of great significance to the research on environmental protection and efficient utilization of land resources at the terrestrial energy receiving system of the Space Solar Power Station.
文摘Background Transparent dressings are commonly used to cover central venous catheter sites. However, it has been suggested that they might not allow adequate moisture vapor transmission, resulting in local moistness that promotes bacterial growth. We compared the moisture vapor transmission rates （MVTRs） of different, currently used transparent and traditional gauze dressings. We aimed to determine the MVTRs at different temperatures and humidities. Methods The dressings were used to seal 50-ml plastic centrifuge tubes containing 20 ml deionized water： Tubes in group 1 were covered with 12 layers of ordinary gauze, group 2 with IV3000, group 3 with OPSITE FLEXlGRID, group 4 with 3M HP Tegaderm, and group 5 with 3M Tegaderm. The tubes were placed upright in an artificial climate cabinet, so that the dressings were not touching the water, in order to simulate the conditions of medical dressings in contact with the skin. The average MVTRs were determined under different conditions. MVTRs were also determined with tubes from groups 2-5 laid on their sides, allowing the dressings to touch the water, so simulating contact of the dressings with sweating skin, or wounded skin with exudates. We also calculated the dressings＇ self-reactive abilities by comparing their MVTRs in contact with the water surface with those when not in contact with the water surface. Results Group 1 demonstrated the highest MVTR, followed by groups 2, 4, 3 and 5 under conditions simulating contact of the dressings with normal skin at the following temperatures and humidities： 20℃/30%, 20℃/60%, 20℃/90%, 37℃/30%, 37℃/60% and 37℃/90%. When the relative humidity （RH） increased, the MVTRs decreased. The MVTRs differed significantly among different dressings and RHs： At high temperature （37℃） and high humidity （90%）, the MVTR of the transparent dressings in group 2 was higher than that of group 1 （P 〈0.01）. The reactive MVTR was highest in group 2 （10.2-16.3 times 〉MVTR） while that of group 4 was second highest （2.6-9.6 times 〉MVTR）. Conclusions RH and temperature had significant effects on the MVTRs of different dressings. The IV3000 transparent dressing used in group 2 was as effective as ordinary gauze. These results suggest that increased infection rates due to low MVTRs might not be a problem. The clinical implications of these observations for catheter-related infections need to be further investigated in multicenter studies.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61771434,91123036,61178058,61275166,and 61076111)the National Science Fund for Distinguished Young Scholars,China(Grant No.51225504)
文摘The coupled resonator-induced transparency （CRIT） phenomenon, which is analogous to electromagnetically induced transparency in atomic systems, can occur in an original integrated optical resonator system due to the coherent interference of the coupled optical resonators. The system was composed of three ring resonators on silicon, each with the same cavity size, and the optical coupling to the input and output ports was achieved using grating with a power coupling efficiency of 36%. A CRIT resonance whose spectrum shows a narrow transparency peak with a low group velocity was demonstrated. The quality factor of the ring resonator can attain a value up to 6x 104, and the harmonic wavelength can be controlled by adjusting the temperature. The through and drop transmission spectra of the resonator are reconciled well with each other and also consistent well with the theoretical analysis.
基金the Hongliu Excellent Youth Talent Support Program of Lanzhou University of Technology and the National Natural Science Foundation of China(Nos.61561031 and 61562058)。
文摘A high-performance noncoherent transmission scheme is proposed in the broadcasting phase of a twoway relay transmission(TWRT),where multiple-symbol differential detection(MSDD)is performed because of its excellent detection performance with no channel estimation.Specifically,the generalized likelihood ratio test aided MSDD(GLRT-MSDD)is developed for the down-link.Furthermore,GLRT-MSDD is reformulated and a semidefinite relaxation aided MSDD(SDR-MSDD)is proposed.The reformulation of GLRT-MSDD to SDR-MSDD is desirable owing to its reduced complexity.Performance analysis and the simulations validate that the proposed SDR-MSDD provides the bit-error-rate performance close to that of GLRT-MSDD with reasonable complexity in TWRT.
