An optimized transducer prototype with a sandwich structure vibrated longitudinally is proposed for a transmitter in acoustic logging, especially in acoustic logging while drilling, 5y taking account of drilling envir...An optimized transducer prototype with a sandwich structure vibrated longitudinally is proposed for a transmitter in acoustic logging, especially in acoustic logging while drilling, 5y taking account of drilling environments with high temperature and pressure, as well as strong collar drilling vibration during the drilling process. Aimed to improve the transmitting performance, numerical and experimental studies for the transducer optimization are conducted. The impact of location and length of the piezoelectric stack on resonance characteristics arid effective electromeehanical coupling coefficient is calculated and analyzed. Admittance and transmitting performance of the proposed transducer are measured in laboratory experiments, and the results are compared with simulated ones. It is shown that the newly proposed transducer has higher transmitting performance with lower resonance frequencies. This work provides theoretical and experimental bases for transducer designing and acoustic wave measurements in acoustic logging, especially in acoustic logging while drilling.展开更多
In the present paper, the effects of moxibustion on the immune organs, on the multiplication reactivity of the splenic lymphocyte and the reactivity to the IL - 2, and on the transmitters in brain tissues of the mice ...In the present paper, the effects of moxibustion on the immune organs, on the multiplication reactivity of the splenic lymphocyte and the reactivity to the IL - 2, and on the transmitters in brain tissues of the mice with "yang deficiency" were studied. 30 mice were randomly divided into three groups: the normal group, the peng deficiency control group and the moxibustion treated group. Our study found out that in the mice of yang deficienly, the atrophy of the immunt organs was prevented, the reactivity of the splenocyte and the reactivity to IL - 2 were heightened, the amounts of the DA, NE and E in brain were increased significantly after moxibustion on the Point Shengshu. It can be held that moxibustion may protect the immune organs and regulate the immunity of the mouse with yang deficienly, and the effects may be contributed to the increase of the nervous transmitters in the brain.展开更多
An Ion Cyclotron Range of Frequency （ICRF） system with a radio frequency （RF） power of 4×1.5 MW was developed for the Experimental Advanced Superconducting Tokamak （EAST）. High RF power transmitters were de...An Ion Cyclotron Range of Frequency （ICRF） system with a radio frequency （RF） power of 4×1.5 MW was developed for the Experimental Advanced Superconducting Tokamak （EAST）. High RF power transmitters were designed as a part of the research and development （R^D） for an ICRF system with long pulse operation at megawatt levels in a frequency range of 25 MHz to 70 MHz. Studies presented in this paper cover the following parts of the high power transmitter： the three staged high power amplifier, which is composed of a 5 kW wide- band solid state amplifier, a 100 kW tetrode drive stage amplifier and a 1.5 MW tetrode final stage amplifier, and the DC high voltage power supply （HVPS）. Based on engineering design and static examinations, the RF transmitters were tested using a matched dummy load where an RF output power of 1.5 MW was achieved. The transmitters provide 6 MW RF power in primary phase and will reach a level up to 12 MW after a later upgrade. The transmitters performed successfully in stable operations in EAST and HT-7 devices. Up to 1.8 MW of RF power was injected into plasmas in EAST ICRF heating experiments during the 2010 autumn campaign and plasma performance was greatly improved.展开更多
A novel sutureless surgical technique has been successfully used to implant acoustic transmitters in relatively large rainbow trout Oncorhynchus mykiss with a tag-to-body-ratio of 0.88%. This study examined the same t...A novel sutureless surgical technique has been successfully used to implant acoustic transmitters in relatively large rainbow trout Oncorhynchus mykiss with a tag-to-body-ratio of 0.88%. This study examined the same technique in smaller rainbow trout in two, 12-week trials comparing both sutured and sutureless surgical techniques. In the first trial using a tag-to-body-ratio of 1.9% ± 0.04%, tag retention was only 16.6% in fish without sutures, which was significantly lower than the 83.3% retention with sutured incisions. Similarly, in the second trial with a tag-to-body-ratio of 3.2% ± 0.03%, tag retention was 55.5% without sutures, which was significantly lower than the 90.0% retention using sutures. Mortality was not significantly different between treatments in either trial. The results of this study indicate that sutures must be used during surgeries to implant acoustic transmitters in relatively smaller fish with tag-to-body-ratios at or above 1.9%.展开更多
With the rapid development of science and technology, radio and television are becoming more and more popular. In addition, the continuous improvement of people's spiritual and cultural enthusiasm puts forward hig...With the rapid development of science and technology, radio and television are becoming more and more popular. In addition, the continuous improvement of people's spiritual and cultural enthusiasm puts forward higher requirements for radio and television. In order to ensure signal coverage, most radio and television stations choose high mountains. There are some problems and shortcomings when starting the mountain station. The integrity, integrity and reliability of radio station facilities and equipment depend on the security of transmissions and broadcasts. In order to ensure the safety and high-quality transmission of broadcast signals, the daily safety management of equipment in the computer room is very important.展开更多
Modern optical communications rely heavily on dense wavelength-division multiplexing(DWDM)technology because of its capability of significantly increasing transmission channels.Here,we demonstrate,for the first time t...Modern optical communications rely heavily on dense wavelength-division multiplexing(DWDM)technology because of its capability of significantly increasing transmission channels.Here,we demonstrate,for the first time to the best of our knowledge,a compact photonic chip for DWDM transmitters on lithiumniobate-on-insulator(LNOI)by introducing the array of 2×2 Fabry–Perot(FP)cavity electro-optic(EO)modulators.A four-channel LNOI photonic chip for DWDM is designed and realized with a channel spacing of 1.6 nm(which is the narrowest one reported until now for LNOI optical transmitters),exhibiting a total excess loss of 1.3 dB and high 3-dB EO bandwidths of>67 GHz for all channels.Specifically,these four 2×2 FP cavities are designed with broadened LNOI photonic waveguides in the cavity sections,and they are placed very closely on the chip so that their resonance wavelengths are aligned precisely with the desired channelspacing of∼1.6 nm.Finally,the generation of 4×80-Gbps on–off keying and 4×100-Gbps PAM4 signals is demonstrated successfully with four channels,and the power consumption is as low as∼5.1 fJ∕bit.The present photonic chip has a compact footprint of about 0.78 mm×0.58 mm,showing great potential to work with more than four channels and to be very useful for future large-capacity optical links.展开更多
The migratory nature of avian species is well known not only to researchers but also to the general public,becoming engrained in cultural traditions and even children's fairy tales.However,our understanding of the...The migratory nature of avian species is well known not only to researchers but also to the general public,becoming engrained in cultural traditions and even children's fairy tales.However,our understanding of these charismatic behaviors made great strides in the 1990s with the advent of small,light-weighted satellite transmitters capable of longterm tracking(Argos,2016).The emergence of this new technology made it possible to track a broader range of species at higher resolution than ever before.In turn,this data enabled detailed understanding of individual avian behavior and habitats,including transboundary migration routes.展开更多
Wave-particle interactions play a fundamental role in the dynamic variability of Earth’s donut-shaped radiation belts that are highly populated by magnetically trapped energetic particles and characteristically separ...Wave-particle interactions play a fundamental role in the dynamic variability of Earth’s donut-shaped radiation belts that are highly populated by magnetically trapped energetic particles and characteristically separated by the slot devoid of high energetic electrons.Owing to the continuous accumulation of high-quality wave and particle measurements from multiple satellites in geospace,the important contribution of ground-based very-low-frequency(VLF)transmitter waves to the electron dynamics in the near-Earth space has been unprecedently advanced,in addition to those established findings of the significant effects of a variety of naturally occurring magnetospheric waves.This paper focuses on the artificial modification of Earth’s inner radiation belt and slot by artificial VLF transmitter emissions.We review the global distributions of VLF transmitter waves in geospace,their scattering effects on radiation belt electrons in terms of both theoretical and observational analyses,and diffusion simulation results of wave-particle interactions along with data-model comparisons.We start with a brief review of the radiation belt electron dynamics and an introduction of anthropogenic VLF transmitter waves.Subsequently,we review the global morphology of in situ VLF transmitter waves corresponding to different transmitter locations,including their day-night asymmetry,geographic distributions,seasonal and geomagnetic activity dependence,and wave propagation features.Existed theoretical and observational analyses of electron scattering effects by VLF transmitter waves are then reviewed to approach the underlying physics that can modulate the spatio-temporal variations of the electron radiation belts.Further Fokker-Planck electron diffusion simulations and their comparisons with realistic satellite observations clearly indicate that VLF transmitter emissions can effectively remove energetic electrons to produce a radially bifurcated electron belt,thereby quantitatively confirming the direct link between operations of VLF transmitters at ground and changes of the energetic electron environment in space.We finally discuss the unsolved problems and possible future research in this area,which has important implications for potential mitigation of the natural particle radiation environment with active means.展开更多
Dense cropping increases crop yield but intensifies resource competition,which reduces single plant yield and limits potential yield growth.Optimizing canopy spacing could enhance resource utilization,support crop mor...Dense cropping increases crop yield but intensifies resource competition,which reduces single plant yield and limits potential yield growth.Optimizing canopy spacing could enhance resource utilization,support crop morphological development and increase yield.Here,a three-year study was performed to verify the feasibility of adjusting row spacing to further enhance yield in densely planted soybeans.Of three row-spacing configurations(40-40,20-40,and 20-60 cm)and two planting densities(normal 180,000 plants ha 1 and high 270,000 plants ha 1).The differences in canopy structure,plant morphological development,photosynthetic capacity and their impact on yield were analyzed.Row spacing configurations have a significant effect on canopy transmittance(CT).The 20-60 cm row spacing configuration increased CT and creates a favorable canopy light environment,in which plant height is reduced,while branching is promoted.This approach reduces plant competition,optimizes the developments of leaf area per plant,specific leaf area,leaf area development rate,leaf area duration and photosynthetic physiological indices(F_(v)/F_(m),ETR,P_(n)).The significant increase of 11.9%-34.2%in canopy apparent photosynthesis(CAP)is attributed to the significant optimization of plant growth and photosynthetic physiology through CT,an important contributing factor to yield increases.The yield in the 20-60 cm treatment is 4.0%higher than in equidistant planting under normal planting density,but 5.9%under high density,primarily driven by CAP and pod number.These findings suggest that suitable row spacing configurations optimize the light environment for plants,promote source-sink transformation in soybeans,and further improve yield.In practice,a 20-60 cm row spacing configuration could be employed for high-density soybean planting to achieve a more substantial yield gain.展开更多
The microwave wireless power transmission technologies for space solar power station are a crucial field in the international space sector,where various countries are competing in its development.This paper surveys th...The microwave wireless power transmission technologies for space solar power station are a crucial field in the international space sector,where various countries are competing in its development.This paper surveys the research experiments and development efforts related to space solar power stations and microwave wireless power transmission technologies worldwide.The objective is to assess the progress and current state of this technological foundation,determine the necessary focus for developing high-power microwave wireless power transmission technology,and provide clarity on the direction of future technology development in these areas.Finally,a distributed space solar power station plan that is immediately feasible is proposed.展开更多
A kind of novel architecture of unslotted photonic packet switching wavelength division multiplexing （WDM） ring network with tunable transmitters and fixed receivers was proposed. In the network the wavelength was u...A kind of novel architecture of unslotted photonic packet switching wavelength division multiplexing （WDM） ring network with tunable transmitters and fixed receivers was proposed. In the network the wavelength was used as optical packet label and node media access controller （MAC） address. Optical packets transmitter was made up of tunable laser that was modulated at 10, 40 Gb/s or higher. Optical packet receiver was made up of Bragg grating, circulator, and fixed receiver. Used as metropolitan access network, it is shown through simulation how a multi-token MAC protocol can be implemented to avoid packet collision and achieve efficient bandwidth utilization. Packet delay, throughput, and packet dropping probability results are presented under uniform and none uniform Possion traffic.展开更多
An on-line electric vehicle(OLEV)uses a wireless charging phenomenon,in which power transmitters are installed beneath the road and the OLEV’s battery is charged remotely.This paper deals with the optimization of two...An on-line electric vehicle(OLEV)uses a wireless charging phenomenon,in which power transmitters are installed beneath the road and the OLEV’s battery is charged remotely.This paper deals with the optimization of two key economic and design parameters,i.e.,the size of the battery and the power transmitters allocation.A complete model configuration of the OLEV system,including the vehicle design and power transmitter,is implemented using MATLAB/Simulink.The battery’s state of charge(SOC)rises and drops according to the vehicle’s velocity and power collection and consumption.The mixed integer programming(MIP)model is used for cost calculation.Therefore,with the help of the SOC graph and MIP model,the battery size and the number of power transmitters,along with their placements,are optimized.The proposed model is applicable to both closed and open environments as it accepts both regulated and deregulated velocities.Two test cases are performed for this purpose.The first test case deals with regulated velocity for which we have applied the KAIST campus OLEV’s velocity along with its 13 kWh battery size and 4 power transmitters,and then applied the suggested solution with the same velocity and route i.e.,8 power transmitters with shorter lengths and reduced battery size(3.25 kWh;one-fourth of the first case).SOC is found within limits at the end of the route,saving$1600 and validating the proposed model in this paper.For the second test case,we use deregulated velocity and optimize both parameters,using the same approach.展开更多
Real-time water-medium endoscopic images can assist doctors in performing operations such as tissue cleaning and nucleus pulpous removal.During medical operating procedures,it is inevitable that tissue particles,debri...Real-time water-medium endoscopic images can assist doctors in performing operations such as tissue cleaning and nucleus pulpous removal.During medical operating procedures,it is inevitable that tissue particles,debris and other contaminants will be suspended within the viewing area,resulting in blurred images and the loss of surface details in biological tissues.Currently,few studies have focused on enhancing such endoscopic images.This paper proposes a water-medium endoscopic image processing method based on dual transmittance in accordance with the imaging characteristics of spinal endoscopy.By establishing an underwater imaging model for spinal endoscopy,we estimate the transmittance of the endoscopic images based on the boundary constraints and local image contrast.The two transmittances are then fused and combined with transmittance maps and ambient light estimations to restore the images before attenuation,ultimately enhancing the details and texture of the images.Experiments comparing classical image enhancement algorithms demonstrate that the proposed algorithm could effectively improve the quality of spinal endoscopic images.展开更多
Metasurfaces offer exceptional capabilities for controlling electromagnetic waves,enabling the realization of unique electromagnetic properties.As communication technology continues to evolve,metasurfaces present prom...Metasurfaces offer exceptional capabilities for controlling electromagnetic waves,enabling the realization of unique electromagnetic properties.As communication technology continues to evolve,metasurfaces present promising applications in wireless communications.This paper reviews the latest advancements in metasurface research within the communication sector,explores metasurface-based wireless relay technologies,and summarizes various wireless communication methods employing different types of metasurfaces across diverse modulation schemes.This paper provides a detailed discussion on the design of wireless communication systems based on coding metasurfaces to simplify transmitter architecture,as well as the development of intelligent coding metasurfaces in the communication field.It also elaborates on the application of vector vortex light fields in metasurface communication.Finally,it offers a forward-looking perspective on wireless communication systems that incorporate coded metasurfaces.This review aims to furnish researchers with a thorough understanding of the current state and future directions of coded metasurface applications in communications.展开更多
We synthesized tungsten-doped vanadium dioxide(W-VO_(2))particles via a one-step hydrothermal method,followed by their integration with antimony-doped tin oxide(ATO)nanoparticles to formulate a composite coating.Subse...We synthesized tungsten-doped vanadium dioxide(W-VO_(2))particles via a one-step hydrothermal method,followed by their integration with antimony-doped tin oxide(ATO)nanoparticles to formulate a composite coating.Subsequently,the VO_(2)/ATO composite coating was fabricated through a spin-coating process.The impact of varying W-VO_(2) content and coating thickness on the performance of the composite coatings was systematically investigated by employing X-ray diffraction,particle size distribution analysis,spectrometry,and other pertinent test methodologies.Our findings revealed that an escalation in both W-VO_(2) content and coating thickness retained high transmittance in the near-infrared band at lower temperatures.However,as the temperature increased,a notable reduction in transmittance in the near-infrared band was observed,alongside a slight decrease in transmittance within the visible band.Remarkably,when the W-VO_(2) content reached 5%and the coating thickness was 1253 nm,the transmittance of the composite coating surpassed 80%.Furthermore,the heat insulation effect achieved a remarkable 10.0℃increase.Consequently,the synthesized composite coating demonstrates significant potential for smart glass applications,particularly in the realm of heat-insulating glass.展开更多
This paper presents a 4-level pulse amplitude modulation(PAM-4)distributed feedback(DFB)laser driver.The driver adopts a digital slicing architecture to achieve high linearity by adjusting the weights of three thermom...This paper presents a 4-level pulse amplitude modulation(PAM-4)distributed feedback(DFB)laser driver.The driver adopts a digital slicing architecture to achieve high linearity by adjusting the weights of three thermometer-coded main paths.An efficient-biased output stage structure is proposed to reduce power consumption while avoiding the degradation of out-put node bandwidth typically induced by parasitic capacitance in high-current bias path.A two-tap linear and nonlinear feed-for-ward equalizer(FFE)is implemented in the digital domain to extend bandwidth limitations and compensate for the dynamic nonlinearity of the DFB laser.The nonlinear FFE is realized at the cost of lower power consumption and smaller area by utiliz-ing the simultaneity of low-speed parallel data.The chip is fabricated in 28 nm CMOS process.Measurement results indicate that,with a laser bias current of 40 mA,a modulation current of 20 mApp,and an operating rate of 32 Gb/s PAM-4,the overall power consumption of the chip is 372 mW,corresponding to an energy efficiency of 11.6 pJ/b.展开更多
In general, the low-frequency capability of noise reduction of conventional anti-noise transmitters and receivers is not encouraging, but more and more sound energy of the modern high-intensity noise environments conc...In general, the low-frequency capability of noise reduction of conventional anti-noise transmitters and receivers is not encouraging, but more and more sound energy of the modern high-intensity noise environments concentrates in that frequency range. Active anti-noise transmitters and receivers, which are developed from active ear defenders, supply the devices not only the benefit of advanced low-frequency anti-noise capability, but also a selectivity in sound reduction. The latter virtue ensures a high intelligibility of speech when the low-frequency noise is highly attenuated. On the basis of ref. [1], a thorough discussion on the principles, structures and experimental results of active anti-noise transmitters and receivers are given in this paper.展开更多
Recently,high-performance thin-film lithium niobate optical modulators have emerged that,together with advanced multiplexing technologies,are highly expected to satisfy the ever-growing demand for high-capacity optica...Recently,high-performance thin-film lithium niobate optical modulators have emerged that,together with advanced multiplexing technologies,are highly expected to satisfy the ever-growing demand for high-capacity optical interconnects utilizing multiple channels.Accordingly,in this study,a compact lithium-niobate-on-insulator(LNOI)photonic chip was adopted to establish four-channel wavelength-division-multiplexing(WDM)transmitters,comprising four optical modulators based on ultracompact 2×2 Fabry-Perot cavities and a four-channel WDM filter based on multimode waveguide gratings.The fabricated chip with four wavelength channels has a total footprint as compact as 0.3×2.8 mm^(2),and exhibits an excess loss of~0.8 dB as well as low inter-channel crosstalk of<–22 dB.Using this LNOI photonic chip,high-capacity data transmissions of 320 Gbps(4×80 Gbps)on-off-keying signals and 400 Gbps(4×100 Gbps)four-level pulse amplitude signals were successfully realized with the ultra-low power consumption of 11.9 fJ/bit.展开更多
This paper describes a low-pass reconfigurable baseband filter for GSM, TD-SCDMA and WCDMA multi-mode transmitters. To comply with 3GPP emission mask and limit TX leakage at the RX band, the out- of-band noise perform...This paper describes a low-pass reconfigurable baseband filter for GSM, TD-SCDMA and WCDMA multi-mode transmitters. To comply with 3GPP emission mask and limit TX leakage at the RX band, the out- of-band noise performance is optimized. Due to the distortion caused by the subthreshold leakage current of the switches used in capacitor array, a capacitor bypass technique is proposed to improve the filter＇s linearity. An automatic frequency tuning circuit is adopted to compensate the cut-off frequency variation. Simulation results show that the filter achieves an in-band input-referred third-order intercept point （IIP3） of 47 dBm at 1.2-V power supply and the out-of-band noise can meet TX SAW-less requirement for WCDMA ＆ TD-SCDMA. The baseband filter incorporates -40 to 0 dB programmable gain control that is accurately variable in 0.5 dB steps. The filter＇s cut-off frequency can be reconfigured for GSM/TD-SCDMA/WCDMA multi-mode transmitter. The implemented baseband filter draws 3.6 mA from a 1.2-V supply in a 0.13 μm CMOS process.展开更多
In recent years,propelled by the rapid iterative advancements in digital imaging technology and the semiconductor industry,encompassing microelectronic design,manufacturing,packaging,and testing,time-of-flight(ToF)-ba...In recent years,propelled by the rapid iterative advancements in digital imaging technology and the semiconductor industry,encompassing microelectronic design,manufacturing,packaging,and testing,time-of-flight(ToF)-based imaging systems for acquiring depth information have garnered considerable attention from both academia and industry.This technology has emerged as a focal point of research within the realm of 3D imaging.Owing to its relatively straightforward principles and exceptional performance,ToF technology finds extensive applications across various domains including human−computer interaction,autonomous driving,industrial inspection,medical and healthcare,augmented reality,smart homes,and 3D reconstruction,among others.Notably,the increasing maturity of ToF-based LiDAR systems is evident in current developments.This paper comprehensively reviews the fundamental principles of ToF technology and LiDAR systems,alongside recent research advancements.It elucidates the innovative aspects and technical challenges encountered in both transmitter(TX)and receiver(RX),providing detailed discussions on corresponding solutions.Furthermore,the paper explores prospective avenues for future research,offering valuable insights for subsequent investigations.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 41474160 and 11304347
文摘An optimized transducer prototype with a sandwich structure vibrated longitudinally is proposed for a transmitter in acoustic logging, especially in acoustic logging while drilling, 5y taking account of drilling environments with high temperature and pressure, as well as strong collar drilling vibration during the drilling process. Aimed to improve the transmitting performance, numerical and experimental studies for the transducer optimization are conducted. The impact of location and length of the piezoelectric stack on resonance characteristics arid effective electromeehanical coupling coefficient is calculated and analyzed. Admittance and transmitting performance of the proposed transducer are measured in laboratory experiments, and the results are compared with simulated ones. It is shown that the newly proposed transducer has higher transmitting performance with lower resonance frequencies. This work provides theoretical and experimental bases for transducer designing and acoustic wave measurements in acoustic logging, especially in acoustic logging while drilling.
文摘In the present paper, the effects of moxibustion on the immune organs, on the multiplication reactivity of the splenic lymphocyte and the reactivity to the IL - 2, and on the transmitters in brain tissues of the mice with "yang deficiency" were studied. 30 mice were randomly divided into three groups: the normal group, the peng deficiency control group and the moxibustion treated group. Our study found out that in the mice of yang deficienly, the atrophy of the immunt organs was prevented, the reactivity of the splenocyte and the reactivity to IL - 2 were heightened, the amounts of the DA, NE and E in brain were increased significantly after moxibustion on the Point Shengshu. It can be held that moxibustion may protect the immune organs and regulate the immunity of the mouse with yang deficienly, and the effects may be contributed to the increase of the nervous transmitters in the brain.
基金supported by National Magnetic Confinement Fusion Science Program of China (No.2010GB110000)partly by Knowledge Innovation Program of the Chinese Academy of Sciences (No.Y05FCQ1126)partly supported by the Japan Society for the Promotion of Science-Chinese Academy of Sciences (JSPS-CAS) Core University Program on Plasma Physics and Nuclear Fusion
文摘An Ion Cyclotron Range of Frequency （ICRF） system with a radio frequency （RF） power of 4×1.5 MW was developed for the Experimental Advanced Superconducting Tokamak （EAST）. High RF power transmitters were designed as a part of the research and development （R^D） for an ICRF system with long pulse operation at megawatt levels in a frequency range of 25 MHz to 70 MHz. Studies presented in this paper cover the following parts of the high power transmitter： the three staged high power amplifier, which is composed of a 5 kW wide- band solid state amplifier, a 100 kW tetrode drive stage amplifier and a 1.5 MW tetrode final stage amplifier, and the DC high voltage power supply （HVPS）. Based on engineering design and static examinations, the RF transmitters were tested using a matched dummy load where an RF output power of 1.5 MW was achieved. The transmitters provide 6 MW RF power in primary phase and will reach a level up to 12 MW after a later upgrade. The transmitters performed successfully in stable operations in EAST and HT-7 devices. Up to 1.8 MW of RF power was injected into plasmas in EAST ICRF heating experiments during the 2010 autumn campaign and plasma performance was greatly improved.
文摘A novel sutureless surgical technique has been successfully used to implant acoustic transmitters in relatively large rainbow trout Oncorhynchus mykiss with a tag-to-body-ratio of 0.88%. This study examined the same technique in smaller rainbow trout in two, 12-week trials comparing both sutured and sutureless surgical techniques. In the first trial using a tag-to-body-ratio of 1.9% ± 0.04%, tag retention was only 16.6% in fish without sutures, which was significantly lower than the 83.3% retention with sutured incisions. Similarly, in the second trial with a tag-to-body-ratio of 3.2% ± 0.03%, tag retention was 55.5% without sutures, which was significantly lower than the 90.0% retention using sutures. Mortality was not significantly different between treatments in either trial. The results of this study indicate that sutures must be used during surgeries to implant acoustic transmitters in relatively smaller fish with tag-to-body-ratios at or above 1.9%.
文摘With the rapid development of science and technology, radio and television are becoming more and more popular. In addition, the continuous improvement of people's spiritual and cultural enthusiasm puts forward higher requirements for radio and television. In order to ensure signal coverage, most radio and television stations choose high mountains. There are some problems and shortcomings when starting the mountain station. The integrity, integrity and reliability of radio station facilities and equipment depend on the security of transmissions and broadcasts. In order to ensure the safety and high-quality transmission of broadcast signals, the daily safety management of equipment in the computer room is very important.
基金supported by the National Key Research and Development Program of China(Grant Nos.2018YFB2200200 and 2018YFB2200201)the National Natural Science Foundation of China(NSFC)(Grant Nos.92150302,62135012,U23B2047,and 62321166651)+2 种基金the Zhejiang Provincial Natural Science Foundation(Grant No.LDT23F04012F05)the Zhejiang Provincial Key Research and Development Program(Grant No.2021C01199)the Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(Grant No.2021R01001).
文摘Modern optical communications rely heavily on dense wavelength-division multiplexing(DWDM)technology because of its capability of significantly increasing transmission channels.Here,we demonstrate,for the first time to the best of our knowledge,a compact photonic chip for DWDM transmitters on lithiumniobate-on-insulator(LNOI)by introducing the array of 2×2 Fabry–Perot(FP)cavity electro-optic(EO)modulators.A four-channel LNOI photonic chip for DWDM is designed and realized with a channel spacing of 1.6 nm(which is the narrowest one reported until now for LNOI optical transmitters),exhibiting a total excess loss of 1.3 dB and high 3-dB EO bandwidths of>67 GHz for all channels.Specifically,these four 2×2 FP cavities are designed with broadened LNOI photonic waveguides in the cavity sections,and they are placed very closely on the chip so that their resonance wavelengths are aligned precisely with the desired channelspacing of∼1.6 nm.Finally,the generation of 4×80-Gbps on–off keying and 4×100-Gbps PAM4 signals is demonstrated successfully with four channels,and the power consumption is as low as∼5.1 fJ∕bit.The present photonic chip has a compact footprint of about 0.78 mm×0.58 mm,showing great potential to work with more than four channels and to be very useful for future large-capacity optical links.
文摘The migratory nature of avian species is well known not only to researchers but also to the general public,becoming engrained in cultural traditions and even children's fairy tales.However,our understanding of these charismatic behaviors made great strides in the 1990s with the advent of small,light-weighted satellite transmitters capable of longterm tracking(Argos,2016).The emergence of this new technology made it possible to track a broader range of species at higher resolution than ever before.In turn,this data enabled detailed understanding of individual avian behavior and habitats,including transboundary migration routes.
基金supported by the National Natural Science Foundation of China(Grant Nos.42025404,42188101,41904144,41704162)the Fundamental Research Funds for the Central Universities(Grant Nos.2042021kf1045,2042021kf1056)+1 种基金the B-type Strategic Priority Program of the Chinese Academy of Sciences(Grant No.XDB41000000)the Pre-research projects on Civil Aerospace Technologies(Grant Nos.D020308,D020104&D020303).
文摘Wave-particle interactions play a fundamental role in the dynamic variability of Earth’s donut-shaped radiation belts that are highly populated by magnetically trapped energetic particles and characteristically separated by the slot devoid of high energetic electrons.Owing to the continuous accumulation of high-quality wave and particle measurements from multiple satellites in geospace,the important contribution of ground-based very-low-frequency(VLF)transmitter waves to the electron dynamics in the near-Earth space has been unprecedently advanced,in addition to those established findings of the significant effects of a variety of naturally occurring magnetospheric waves.This paper focuses on the artificial modification of Earth’s inner radiation belt and slot by artificial VLF transmitter emissions.We review the global distributions of VLF transmitter waves in geospace,their scattering effects on radiation belt electrons in terms of both theoretical and observational analyses,and diffusion simulation results of wave-particle interactions along with data-model comparisons.We start with a brief review of the radiation belt electron dynamics and an introduction of anthropogenic VLF transmitter waves.Subsequently,we review the global morphology of in situ VLF transmitter waves corresponding to different transmitter locations,including their day-night asymmetry,geographic distributions,seasonal and geomagnetic activity dependence,and wave propagation features.Existed theoretical and observational analyses of electron scattering effects by VLF transmitter waves are then reviewed to approach the underlying physics that can modulate the spatio-temporal variations of the electron radiation belts.Further Fokker-Planck electron diffusion simulations and their comparisons with realistic satellite observations clearly indicate that VLF transmitter emissions can effectively remove energetic electrons to produce a radially bifurcated electron belt,thereby quantitatively confirming the direct link between operations of VLF transmitters at ground and changes of the energetic electron environment in space.We finally discuss the unsolved problems and possible future research in this area,which has important implications for potential mitigation of the natural particle radiation environment with active means.
基金supported by the Biological Breeding-National Science and Technology Major Project(2023ZD0403305)National Natural Science Foundation of China(32101845)+1 种基金the National Key Research and Development Program of China(2023YFE0105000)the China Agriculture Research System(CARS-04).
文摘Dense cropping increases crop yield but intensifies resource competition,which reduces single plant yield and limits potential yield growth.Optimizing canopy spacing could enhance resource utilization,support crop morphological development and increase yield.Here,a three-year study was performed to verify the feasibility of adjusting row spacing to further enhance yield in densely planted soybeans.Of three row-spacing configurations(40-40,20-40,and 20-60 cm)and two planting densities(normal 180,000 plants ha 1 and high 270,000 plants ha 1).The differences in canopy structure,plant morphological development,photosynthetic capacity and their impact on yield were analyzed.Row spacing configurations have a significant effect on canopy transmittance(CT).The 20-60 cm row spacing configuration increased CT and creates a favorable canopy light environment,in which plant height is reduced,while branching is promoted.This approach reduces plant competition,optimizes the developments of leaf area per plant,specific leaf area,leaf area development rate,leaf area duration and photosynthetic physiological indices(F_(v)/F_(m),ETR,P_(n)).The significant increase of 11.9%-34.2%in canopy apparent photosynthesis(CAP)is attributed to the significant optimization of plant growth and photosynthetic physiology through CT,an important contributing factor to yield increases.The yield in the 20-60 cm treatment is 4.0%higher than in equidistant planting under normal planting density,but 5.9%under high density,primarily driven by CAP and pod number.These findings suggest that suitable row spacing configurations optimize the light environment for plants,promote source-sink transformation in soybeans,and further improve yield.In practice,a 20-60 cm row spacing configuration could be employed for high-density soybean planting to achieve a more substantial yield gain.
基金Entrusted Fund of National Institute of Information and Communications Technology(NICT),Japan(JPJ012368C02401)。
文摘The microwave wireless power transmission technologies for space solar power station are a crucial field in the international space sector,where various countries are competing in its development.This paper surveys the research experiments and development efforts related to space solar power stations and microwave wireless power transmission technologies worldwide.The objective is to assess the progress and current state of this technological foundation,determine the necessary focus for developing high-power microwave wireless power transmission technology,and provide clarity on the direction of future technology development in these areas.Finally,a distributed space solar power station plan that is immediately feasible is proposed.
基金This work was supported by the National Natural Science Foundation of China under Grant No. 90104003.
文摘A kind of novel architecture of unslotted photonic packet switching wavelength division multiplexing （WDM） ring network with tunable transmitters and fixed receivers was proposed. In the network the wavelength was used as optical packet label and node media access controller （MAC） address. Optical packets transmitter was made up of tunable laser that was modulated at 10, 40 Gb/s or higher. Optical packet receiver was made up of Bragg grating, circulator, and fixed receiver. Used as metropolitan access network, it is shown through simulation how a multi-token MAC protocol can be implemented to avoid packet collision and achieve efficient bandwidth utilization. Packet delay, throughput, and packet dropping probability results are presented under uniform and none uniform Possion traffic.
文摘An on-line electric vehicle(OLEV)uses a wireless charging phenomenon,in which power transmitters are installed beneath the road and the OLEV’s battery is charged remotely.This paper deals with the optimization of two key economic and design parameters,i.e.,the size of the battery and the power transmitters allocation.A complete model configuration of the OLEV system,including the vehicle design and power transmitter,is implemented using MATLAB/Simulink.The battery’s state of charge(SOC)rises and drops according to the vehicle’s velocity and power collection and consumption.The mixed integer programming(MIP)model is used for cost calculation.Therefore,with the help of the SOC graph and MIP model,the battery size and the number of power transmitters,along with their placements,are optimized.The proposed model is applicable to both closed and open environments as it accepts both regulated and deregulated velocities.Two test cases are performed for this purpose.The first test case deals with regulated velocity for which we have applied the KAIST campus OLEV’s velocity along with its 13 kWh battery size and 4 power transmitters,and then applied the suggested solution with the same velocity and route i.e.,8 power transmitters with shorter lengths and reduced battery size(3.25 kWh;one-fourth of the first case).SOC is found within limits at the end of the route,saving$1600 and validating the proposed model in this paper.For the second test case,we use deregulated velocity and optimize both parameters,using the same approach.
文摘Real-time water-medium endoscopic images can assist doctors in performing operations such as tissue cleaning and nucleus pulpous removal.During medical operating procedures,it is inevitable that tissue particles,debris and other contaminants will be suspended within the viewing area,resulting in blurred images and the loss of surface details in biological tissues.Currently,few studies have focused on enhancing such endoscopic images.This paper proposes a water-medium endoscopic image processing method based on dual transmittance in accordance with the imaging characteristics of spinal endoscopy.By establishing an underwater imaging model for spinal endoscopy,we estimate the transmittance of the endoscopic images based on the boundary constraints and local image contrast.The two transmittances are then fused and combined with transmittance maps and ambient light estimations to restore the images before attenuation,ultimately enhancing the details and texture of the images.Experiments comparing classical image enhancement algorithms demonstrate that the proposed algorithm could effectively improve the quality of spinal endoscopic images.
基金supported in part by National Natural Science Foundation of China(U24A20307 and 62175224)in part by the science and technology innovation leading talent project of special support plan for high-level talents in Zhejiang Province(2021R52032)+2 种基金in part by the China Jiliang University Basic Research ExpensesZhejiang University Students Science and Technology Innovation Activity Plan-New Talent Plan(2024R409C054)in part by the Natural Science Foundation of Zhejiang Province under Grant(ZCLZ25F0502).
文摘Metasurfaces offer exceptional capabilities for controlling electromagnetic waves,enabling the realization of unique electromagnetic properties.As communication technology continues to evolve,metasurfaces present promising applications in wireless communications.This paper reviews the latest advancements in metasurface research within the communication sector,explores metasurface-based wireless relay technologies,and summarizes various wireless communication methods employing different types of metasurfaces across diverse modulation schemes.This paper provides a detailed discussion on the design of wireless communication systems based on coding metasurfaces to simplify transmitter architecture,as well as the development of intelligent coding metasurfaces in the communication field.It also elaborates on the application of vector vortex light fields in metasurface communication.Finally,it offers a forward-looking perspective on wireless communication systems that incorporate coded metasurfaces.This review aims to furnish researchers with a thorough understanding of the current state and future directions of coded metasurface applications in communications.
基金Funded by Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park(No.Z221100006722022)。
文摘We synthesized tungsten-doped vanadium dioxide(W-VO_(2))particles via a one-step hydrothermal method,followed by their integration with antimony-doped tin oxide(ATO)nanoparticles to formulate a composite coating.Subsequently,the VO_(2)/ATO composite coating was fabricated through a spin-coating process.The impact of varying W-VO_(2) content and coating thickness on the performance of the composite coatings was systematically investigated by employing X-ray diffraction,particle size distribution analysis,spectrometry,and other pertinent test methodologies.Our findings revealed that an escalation in both W-VO_(2) content and coating thickness retained high transmittance in the near-infrared band at lower temperatures.However,as the temperature increased,a notable reduction in transmittance in the near-infrared band was observed,alongside a slight decrease in transmittance within the visible band.Remarkably,when the W-VO_(2) content reached 5%and the coating thickness was 1253 nm,the transmittance of the composite coating surpassed 80%.Furthermore,the heat insulation effect achieved a remarkable 10.0℃increase.Consequently,the synthesized composite coating demonstrates significant potential for smart glass applications,particularly in the realm of heat-insulating glass.
基金supported in part by Beijing Natural Science Foundation(Grant No.L247013)in part by the National Natural Science Foundation of China(Grant No.92373209)+1 种基金in part by Grant from the Chinese Academy of Sciences(Grant No.ZDBS-LY-JSC008)in part by Xiamen major science and technology project(Grant No.3502Z20221003).
文摘This paper presents a 4-level pulse amplitude modulation(PAM-4)distributed feedback(DFB)laser driver.The driver adopts a digital slicing architecture to achieve high linearity by adjusting the weights of three thermometer-coded main paths.An efficient-biased output stage structure is proposed to reduce power consumption while avoiding the degradation of out-put node bandwidth typically induced by parasitic capacitance in high-current bias path.A two-tap linear and nonlinear feed-for-ward equalizer(FFE)is implemented in the digital domain to extend bandwidth limitations and compensate for the dynamic nonlinearity of the DFB laser.The nonlinear FFE is realized at the cost of lower power consumption and smaller area by utiliz-ing the simultaneity of low-speed parallel data.The chip is fabricated in 28 nm CMOS process.Measurement results indicate that,with a laser bias current of 40 mA,a modulation current of 20 mApp,and an operating rate of 32 Gb/s PAM-4,the overall power consumption of the chip is 372 mW,corresponding to an energy efficiency of 11.6 pJ/b.
基金The project is supported financially by the Ministry of Mechano-electronic Industry and the Science Committee of Jiangsu Province.
文摘In general, the low-frequency capability of noise reduction of conventional anti-noise transmitters and receivers is not encouraging, but more and more sound energy of the modern high-intensity noise environments concentrates in that frequency range. Active anti-noise transmitters and receivers, which are developed from active ear defenders, supply the devices not only the benefit of advanced low-frequency anti-noise capability, but also a selectivity in sound reduction. The latter virtue ensures a high intelligibility of speech when the low-frequency noise is highly attenuated. On the basis of ref. [1], a thorough discussion on the principles, structures and experimental results of active anti-noise transmitters and receivers are given in this paper.
基金the National Major Research and Development Program(No.2018YFB2200200/2018YFB2200201)National Science Fund for Distinguished Young Scholars(61725503)+4 种基金National Natural Science Foundation of China(NSFC)(91950205,61961146003,92150302,62105283,62205286)Zhejiang Provincial Natural Science Foundation(LD19F050001)Zhejiang Provincial Major Research and Development Program(No.2021C01199)Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(2021R01001)the Fundamental Research Funds for the Central Universities.The authors thank the Westlake Center for Micro/Nano Fabrication for the partial facility support。
文摘Recently,high-performance thin-film lithium niobate optical modulators have emerged that,together with advanced multiplexing technologies,are highly expected to satisfy the ever-growing demand for high-capacity optical interconnects utilizing multiple channels.Accordingly,in this study,a compact lithium-niobate-on-insulator(LNOI)photonic chip was adopted to establish four-channel wavelength-division-multiplexing(WDM)transmitters,comprising four optical modulators based on ultracompact 2×2 Fabry-Perot cavities and a four-channel WDM filter based on multimode waveguide gratings.The fabricated chip with four wavelength channels has a total footprint as compact as 0.3×2.8 mm^(2),and exhibits an excess loss of~0.8 dB as well as low inter-channel crosstalk of<–22 dB.Using this LNOI photonic chip,high-capacity data transmissions of 320 Gbps(4×80 Gbps)on-off-keying signals and 400 Gbps(4×100 Gbps)four-level pulse amplitude signals were successfully realized with the ultra-low power consumption of 11.9 fJ/bit.
基金Project supported by the Important National Science & Technology Specific Projects(No.2009ZX01031-003-002)the National High Technology Research and Development Program of China(No.2009AA011605)
文摘This paper describes a low-pass reconfigurable baseband filter for GSM, TD-SCDMA and WCDMA multi-mode transmitters. To comply with 3GPP emission mask and limit TX leakage at the RX band, the out- of-band noise performance is optimized. Due to the distortion caused by the subthreshold leakage current of the switches used in capacitor array, a capacitor bypass technique is proposed to improve the filter＇s linearity. An automatic frequency tuning circuit is adopted to compensate the cut-off frequency variation. Simulation results show that the filter achieves an in-band input-referred third-order intercept point （IIP3） of 47 dBm at 1.2-V power supply and the out-of-band noise can meet TX SAW-less requirement for WCDMA ＆ TD-SCDMA. The baseband filter incorporates -40 to 0 dB programmable gain control that is accurately variable in 0.5 dB steps. The filter＇s cut-off frequency can be reconfigured for GSM/TD-SCDMA/WCDMA multi-mode transmitter. The implemented baseband filter draws 3.6 mA from a 1.2-V supply in a 0.13 μm CMOS process.
文摘In recent years,propelled by the rapid iterative advancements in digital imaging technology and the semiconductor industry,encompassing microelectronic design,manufacturing,packaging,and testing,time-of-flight(ToF)-based imaging systems for acquiring depth information have garnered considerable attention from both academia and industry.This technology has emerged as a focal point of research within the realm of 3D imaging.Owing to its relatively straightforward principles and exceptional performance,ToF technology finds extensive applications across various domains including human−computer interaction,autonomous driving,industrial inspection,medical and healthcare,augmented reality,smart homes,and 3D reconstruction,among others.Notably,the increasing maturity of ToF-based LiDAR systems is evident in current developments.This paper comprehensively reviews the fundamental principles of ToF technology and LiDAR systems,alongside recent research advancements.It elucidates the innovative aspects and technical challenges encountered in both transmitter(TX)and receiver(RX),providing detailed discussions on corresponding solutions.Furthermore,the paper explores prospective avenues for future research,offering valuable insights for subsequent investigations.
