To improve the navigation accuracy of an autonomous underwater vehicle （AUV）, a novel terrain passive integrated navigation system （TPINS） is presented. According to the characteristics of the underwater environme...To improve the navigation accuracy of an autonomous underwater vehicle （AUV）, a novel terrain passive integrated navigation system （TPINS） is presented. According to the characteristics of the underwater environment and AUV navigation requirements of low cost and high accuracy, a novel TPINS is designed with a configuration of the strapdown inertial navigation system （SINS）, the terrain reference navigation system （TRNS）, the Doppler velocity sonar （DVS）, the magnetic compass and the navigation computer utilizing the unscented Kalman filter （UKF） to fuse the navigation information from various navigation sensors. Linear filter equations for the extended Kalman filter （EKF）, nonlinear filter equations for the UKF and measurement equations of navigation sensors are addressed. It is indicated from the comparable simulation experiments of the EKF and the UKF that AUV navigation precision is improved substantially with the proposed sensors and the UKF when compared to the EKF. The TPINS designed with the proposed sensors and the UKF is effective in reducing AUV navigation position errors and improving the stability and precision of the AUV underwater integrated navigation.展开更多
In this review,the advanced microwave devices based on the integrated passive device(IPD)technology are expounded and discussed in detail,involving the performance breakthroughs and circuit innovations.Then,the develo...In this review,the advanced microwave devices based on the integrated passive device(IPD)technology are expounded and discussed in detail,involving the performance breakthroughs and circuit innovations.Then,the development trend of IPD-based multifunctional microwave circuits is predicted further by analyzing the current research hot spots.This paper discusses a distinctive research area for microwave circuits and mobile-terminal radio-frequency integrated chips.展开更多
Two hundred and forty-three juvenile rainbow trout <span style="font-size:12px;font-family:Verdana;">Oncorhynchus mykiss<span style="font-size:12px;font-family:Verdana;"> ranging from 7...Two hundred and forty-three juvenile rainbow trout <span style="font-size:12px;font-family:Verdana;">Oncorhynchus mykiss<span style="font-size:12px;font-family:Verdana;"> ranging from 73 to 119 mm <span style="font-size:12px;font-family:Verdana;">were <span style="font-size:12px;font-family:Verdana;">implanted with 8, 9, or 10 mm Passive Integrated Transponder (PIT) tags, with tag retention and fish survival observed for 343 days. Similarly, 173 brown trout <span style="font-size:12px;font-family:Verdana;">Salmo trutta<span style="font-size:12px;font-family:Verdana;"> ranging from 71 to 86 mm were implanted with 8 or 10 mm PIT tags and observed for 293 days. Over the entire duration of the study, rainbow trout ejected only six tags, while no tags were ejected from the brown trout. All of the rainbow trout tag ejections occurred before 50 days post-tagging. There was no significant difference in the length or weight of fish that ejected tags compared to those that retained tags. No fish died during the trials. These results indicate that rainbow trout and brown trout at the sizes used in this study can be safely implanted with, and subsequently retain, up to 10 mm PIT tags for durations of nearly one year.展开更多
This paper proposes the modem passive integrated energy-saving technology of the residential buildings under green building background. The essence of green building is to build a healthy and general environmentally f...This paper proposes the modem passive integrated energy-saving technology of the residential buildings under green building background. The essence of green building is to build a healthy and general environmentally friendly living environment under the premise of reducing the consumption of resources and improving the efficiency of resource utilization in the whole life cycle of construction activities. Green building bearing function is further diversified, integrated, and has a self-initiative. The development of the green building, local isolated from the original single building greening, greening, landscaping site platform, gradually developed for construction area and the surrounding green ecological system of comprehensive, three-dimensional stratified construction and network connection. Its model gradually shows the micro area of the construction of the ecological system and architectural space integration. This paper integrates the passive integrated energysaving technology to construct the novel construction paradigm.展开更多
In order to utilize integrated passive technology in printed circuit boards （PCBs）, manufacturing processing for integrated resistors by lamination method was investigated. Integrated resistors fabricated from Ohmeg...In order to utilize integrated passive technology in printed circuit boards （PCBs）, manufacturing processing for integrated resistors by lamination method was investigated. Integrated resistors fabricated from Ohmega technologies in the experiment were 1 408 pieces per panel with four different patterns A, B, C and D and four resistance values of 25, 50, 75 and 100 fL Six panel per batch and four batches were performed totally. The testing was done for 960 pieces of integrated resistors randomly selected with the same size. The value distribution ranges and the relative standard deviation （RSD） show that the scatter degree of the resistance decreases with the resistor size increasing and/or with the resistance increasing. Patterns D with resistance of 75 and 100% for four patterns have the resistance value variances less than 10%. Patterns C and D with resistance of 100 Ω have the manufacturing tolerance less than 10%. The process capabilities are from about 0.6 to 1.6 for the designed testing patterns, which shows that the integrated resistors fabricated have the potential to be used in multilayer PCBs in the future.展开更多
Due to the small size,variety,and high degree of mixing of herbaceous vegetation,remote sensing-based identification of grassland types primarily focuses on extracting major grassland categories,lacking detailed depic...Due to the small size,variety,and high degree of mixing of herbaceous vegetation,remote sensing-based identification of grassland types primarily focuses on extracting major grassland categories,lacking detailed depiction.This limitation significantly hampers the development of effective evaluation and fine supervision for the rational utilization of grassland resources.To address this issue,this study concentrates on the representative grassland of Zhenglan Banner in Inner Mongolia as the study area.It integrates the strengths of Sentinel-1 and Sentinel-2 active-passive synergistic observations and introduces innovative object-oriented techniques for grassland type classification,thereby enhancing the accuracy and refinement of grassland classification.The results demonstrate the following:(1)To meet the supervision requirements of grassland resources,we propose a grassland type classification system based on remote sensing and the vegetation-habitat classification method,specifically applicable to natural grasslands in northern China.(2)By utilizing the high-spatial-resolution Normalized Difference Vegetation Index(NDVI)synthesized through the Spatial and Temporal Non-Local Filter-based Fusion Model(STNLFFM),we are able to capture the NDVI time profiles of grassland types,accurately extract vegetation phenological information within the year,and further enhance the temporal resolution.(3)The integration of multi-seasonal spectral,polarization,and phenological characteristics significantly improves the classification accuracy of grassland types.The overall accuracy reaches 82.61%,with a kappa coefficient of 0.79.Compared to using only multi-seasonal spectral features,the accuracy and kappa coefficient have improved by 15.94%and 0.19,respectively.Notably,the accuracy improvement of the gently sloping steppe is the highest,exceeding 38%.(4)Sandy grassland is the most widespread in the study area,and the growth season of grassland vegetation mainly occurs from May to September.The sandy meadow exhibits a longer growing season compared with typical grassland and meadow,and the distinct differences in phenological characteristics contribute to the accurate identification of various grassland types.展开更多
With the development of 3D integration technology, microsystems with vertical interconnects are attracting attention from researchers and industry applications. Basic elements of integrated passive devices （IPDs）, i...With the development of 3D integration technology, microsystems with vertical interconnects are attracting attention from researchers and industry applications. Basic elements of integrated passive devices （IPDs）, including inductors, capacitors, and resistors, could dramatically save the tbotprint of the system, optimize the form factor, and improve the performance of radio frequency （RF） systems. In this paper, IPDs using thin film built-up technology are introduced, and the design and characterization of coplanar waveguides （CPWs）, inductors, and capacitors are presented.展开更多
Phase is an intrinsic property of light,and thus a crucial parameter across numerous applications in modern optics.Various methods exist for measuring the phase of light,each presenting challenges and limitationsfrom ...Phase is an intrinsic property of light,and thus a crucial parameter across numerous applications in modern optics.Various methods exist for measuring the phase of light,each presenting challenges and limitationsfrom the mechanical stability requirements of free-space interferometers to the computational complexity usually associated with methods based on spatial light modulators.Here,we utilize a passive photonic integrated circuit to spatially probe phase and intensity distributions of free-space light beams.Phase information is encoded into intensity through a set of passive on-chip interferometers,allowing conventional detectors to retrieve the phase profile of light through single-shot intensity measurements.Furthermore,we use silicon nitride as a material platform for the waveguide architecture,facilitating multi-spectral utilization in the visible spectral range.Our approach for fast,multi-spectral,and spatially resolved measurement of intensity and phase enables a wide variety of potential applications,ranging from microscopy to free-space optical communication.展开更多
In this paper,the methods to detect dust based on passive and active measurements from satellites have been summarized.These include the visible and infrared（VIR） method,thermal infrared（TIR） method,microwave pola...In this paper,the methods to detect dust based on passive and active measurements from satellites have been summarized.These include the visible and infrared（VIR） method,thermal infrared（TIR） method,microwave polarized index（MPI） method,active lidar-based method,and combined lidar and infrared measurement（CLIM） method.The VIR method can identify dust during daytime.Using measurements at wavelengths of 8.5,11.0,and 12.0 fan,the TIR method can distinguish dust from other types of aerosols and cloud,and identify the occurrence of dust over bright surfaces and during night.Since neither the VIR nor the TIR method can penetrate ice clouds,they cannot detect dust beneath ice clouds.The MPI method,however,can identify about 85%of the dust beneath ice clouds.Meanwhile,the active lidar-based method,which uses the Cloud-Aerosol Lidar with Orthogonal Polarization（CALIOP） data and five-dimensional probability distribution functions,can provide very high-resolution vertical profiles of dust aerosols.Nonetheless,as the signals from dense dust and thin clouds are similar in the CALIOP measurements,the lidar-based method may fail to distinguish between them,especially over dust source regions.To address this issue,the CLIM method was developed,which takes the advantages of both TIR measurements（to discriminate between ice cloud and dense dust layers） and lidar measurements（to detect thin dust and water cloud layers）.The results obtained by using the new CLIM method show that the ratio of dust misclassification has been significantly reduced.Finally,a concept module for an integrated multi-satellites dust detection system was proposed to overcome some of the weaknesses inherent in the single-sensor dust detection.展开更多
A broadband monolithic linear single pole, eight throw （SP8T） switch has been fabricated in 180 nm thin film silicon-on-insulator （SOI） CMOS technology with a quad-band GSM harmonic filter in integrated passive de...A broadband monolithic linear single pole, eight throw （SP8T） switch has been fabricated in 180 nm thin film silicon-on-insulator （SOI） CMOS technology with a quad-band GSM harmonic filter in integrated passive devices （IPD） technology, which is developed for cellular applications. The antenna switch module （ASM） features 1.2 dB insertion loss with filter on 2G bands and 0.4 dB insertion loss in 3G bands, less than -45 dB isolation and maximum -103 dB intermodulation distortion for mobile front ends by applying distributed architecture and adaptive supply voltage generator.展开更多
Fish passage facilities are constructed worldwide to enable fish to pass anthropogenic obstacles (i.e., dams) and re-establish river connectivity. The construction of these facilities involves sophisticated engineerin...Fish passage facilities are constructed worldwide to enable fish to pass anthropogenic obstacles (i.e., dams) and re-establish river connectivity. The construction of these facilities involves sophisticated engineering designed to attract fish and enable passage. The behavior of fish encountering these structures, particularly in long vertical slot fishways, has been poorly studied. This study was conducted on the Daduhe River in Southwest China to quantify the upstream passage efficiency and performance of tagged Schizothorax davidi in different sections of a long vertical slot fishway spanning 1228.3 m. The overall passage efficiency was 13% although the passage efficiency in seven sections (A0-A1, A1-A2, A2-A3, A3-A4, A4-A5, A5-A6, A6-A7) ranged from 43% to 100% reflecting differences in slope among sections. The highest passage efficiency was documented in rest pool sections with a slope of 0 (A3–A4, 100% and A6–A7, 100%) and during passage through the dam itself (A5–A6, 90.0%). The lowest passage efficiency was section A2–A3, where a garbage interception facility affected passage efficiency. Average transit time from A0 to A7 was 85.2 h and ranged from 8.8 to 237.6 h. Transit speed varied over various sections. The first section (i.e., A0–A1) had slow transit speeds which presumably was influenced by acclimation and recovery from tag implantation. After this, the transit speed had a slight increase but decreased again. Additionally, more than half (5 out of 9 fish) of the fish fell back after reaching the most upstream section and reascended the fishway which tripled the total passage time for those individuals. No significant diel activity rhythms were observed, but a strong bimodal distribution was noted in fish transit time when passing the first monitoring site. Cox-proportional hazards model showed that transit time was negatively correlated with body size but positively correlated with water level and water temperature. Our study provides valuable insights into activity when passing through a long fishway, which can inform design of fishway structures and operational patterns to improve upstream passage efficiency. Specifically, we recommend increasing the number of resting pools and maintaining appropriate water levels to reduce transit time and fallback frequency in long fishways.展开更多
The GaAs-based TF-IPD fabrication process and equivalent lumped element circuit are utilized to re- duce the circuit size for double-section Wilkinson power divider. Ultimately the dimension of the proposed S-band pow...The GaAs-based TF-IPD fabrication process and equivalent lumped element circuit are utilized to re- duce the circuit size for double-section Wilkinson power divider. Ultimately the dimension of the proposed S-band power divider is reduced to 1.03 × 0.98 mm2. Its measured results show an operating fractional bandwidth of 54%, and return losses and isolation of greater than 20 dB. In addition the excess insertion loss is less than 1.1 dB. More- over the good features contain amplitude and phase equilibrium with the values of better than 0.03 dB and 1.5° separately. This miniaturized power divider could be widely used in RF/microwave circuit systems.展开更多
An ultra-small integrated photonic circuit has been proposed,which incorporates a high-quality-factor passive micro-ring resonator（MR） linked to a vertical grating coupler on a standard silicon-on-insulator（SOI） s...An ultra-small integrated photonic circuit has been proposed,which incorporates a high-quality-factor passive micro-ring resonator（MR） linked to a vertical grating coupler on a standard silicon-on-insulator（SOI） substrate.The experimental results demonstrate that the MR propagation loss is 0.532 dB/cm with a 10μm radius ring resonator,the intrinsic quality factor is as high as 202.000,the waveguide grating wavelength response curve is a 1 dB bandwidth of 40 nm at 1540 nm telecommunication wavelengths,and the measured fiber-to-fiber coupling loss is 10 dB.Furthermore,the resonator wavelength temperature dependence of the 450 nm wide micro-ring resonator is 54.1 pm/℃.Such vertical grating coupler and low loss MR-integrated components greatly promote a key element in biosensors and high-speed interconnect communication applications.展开更多
基金Pre-Research Program of General Armament Department during the11th Five-Year Plan Period (No51309020503)the National Defense Basic Research Program of China (973Program)(No973-61334)+1 种基金the National Natural Science Foundation of China(No50575042)Specialized Research Fund for the Doctoral Program of Higher Education (No20050286026)
文摘To improve the navigation accuracy of an autonomous underwater vehicle （AUV）, a novel terrain passive integrated navigation system （TPINS） is presented. According to the characteristics of the underwater environment and AUV navigation requirements of low cost and high accuracy, a novel TPINS is designed with a configuration of the strapdown inertial navigation system （SINS）, the terrain reference navigation system （TRNS）, the Doppler velocity sonar （DVS）, the magnetic compass and the navigation computer utilizing the unscented Kalman filter （UKF） to fuse the navigation information from various navigation sensors. Linear filter equations for the extended Kalman filter （EKF）, nonlinear filter equations for the UKF and measurement equations of navigation sensors are addressed. It is indicated from the comparable simulation experiments of the EKF and the UKF that AUV navigation precision is improved substantially with the proposed sensors and the UKF when compared to the EKF. The TPINS designed with the proposed sensors and the UKF is effective in reducing AUV navigation position errors and improving the stability and precision of the AUV underwater integrated navigation.
基金Beijing Natural Science Foundation(No.JQ19018)National Natural Science Foundations of China(No.U20A20203 and No.61971052)National Special Support Program for High-Level Personnel Recruitment(No.2018RA2131)。
文摘In this review,the advanced microwave devices based on the integrated passive device(IPD)technology are expounded and discussed in detail,involving the performance breakthroughs and circuit innovations.Then,the development trend of IPD-based multifunctional microwave circuits is predicted further by analyzing the current research hot spots.This paper discusses a distinctive research area for microwave circuits and mobile-terminal radio-frequency integrated chips.
文摘Two hundred and forty-three juvenile rainbow trout <span style="font-size:12px;font-family:Verdana;">Oncorhynchus mykiss<span style="font-size:12px;font-family:Verdana;"> ranging from 73 to 119 mm <span style="font-size:12px;font-family:Verdana;">were <span style="font-size:12px;font-family:Verdana;">implanted with 8, 9, or 10 mm Passive Integrated Transponder (PIT) tags, with tag retention and fish survival observed for 343 days. Similarly, 173 brown trout <span style="font-size:12px;font-family:Verdana;">Salmo trutta<span style="font-size:12px;font-family:Verdana;"> ranging from 71 to 86 mm were implanted with 8 or 10 mm PIT tags and observed for 293 days. Over the entire duration of the study, rainbow trout ejected only six tags, while no tags were ejected from the brown trout. All of the rainbow trout tag ejections occurred before 50 days post-tagging. There was no significant difference in the length or weight of fish that ejected tags compared to those that retained tags. No fish died during the trials. These results indicate that rainbow trout and brown trout at the sizes used in this study can be safely implanted with, and subsequently retain, up to 10 mm PIT tags for durations of nearly one year.
文摘This paper proposes the modem passive integrated energy-saving technology of the residential buildings under green building background. The essence of green building is to build a healthy and general environmentally friendly living environment under the premise of reducing the consumption of resources and improving the efficiency of resource utilization in the whole life cycle of construction activities. Green building bearing function is further diversified, integrated, and has a self-initiative. The development of the green building, local isolated from the original single building greening, greening, landscaping site platform, gradually developed for construction area and the surrounding green ecological system of comprehensive, three-dimensional stratified construction and network connection. Its model gradually shows the micro area of the construction of the ecological system and architectural space integration. This paper integrates the passive integrated energysaving technology to construct the novel construction paradigm.
基金Project(041010) supported by Start-Up Foundation of Northwest University,ChinaProject(UIT/39) supported by University-Industry Collaboration Program from the Innovation and Technology Fund of Hong Kong,China
文摘In order to utilize integrated passive technology in printed circuit boards （PCBs）, manufacturing processing for integrated resistors by lamination method was investigated. Integrated resistors fabricated from Ohmega technologies in the experiment were 1 408 pieces per panel with four different patterns A, B, C and D and four resistance values of 25, 50, 75 and 100 fL Six panel per batch and four batches were performed totally. The testing was done for 960 pieces of integrated resistors randomly selected with the same size. The value distribution ranges and the relative standard deviation （RSD） show that the scatter degree of the resistance decreases with the resistor size increasing and/or with the resistance increasing. Patterns D with resistance of 75 and 100% for four patterns have the resistance value variances less than 10%. Patterns C and D with resistance of 100 Ω have the manufacturing tolerance less than 10%. The process capabilities are from about 0.6 to 1.6 for the designed testing patterns, which shows that the integrated resistors fabricated have the potential to be used in multilayer PCBs in the future.
基金supported by the National Natural Science Foundation of China[grant number 42001386,42271407]within the ESA-MOST China Dragon 5 Cooperation(ID:59313).
文摘Due to the small size,variety,and high degree of mixing of herbaceous vegetation,remote sensing-based identification of grassland types primarily focuses on extracting major grassland categories,lacking detailed depiction.This limitation significantly hampers the development of effective evaluation and fine supervision for the rational utilization of grassland resources.To address this issue,this study concentrates on the representative grassland of Zhenglan Banner in Inner Mongolia as the study area.It integrates the strengths of Sentinel-1 and Sentinel-2 active-passive synergistic observations and introduces innovative object-oriented techniques for grassland type classification,thereby enhancing the accuracy and refinement of grassland classification.The results demonstrate the following:(1)To meet the supervision requirements of grassland resources,we propose a grassland type classification system based on remote sensing and the vegetation-habitat classification method,specifically applicable to natural grasslands in northern China.(2)By utilizing the high-spatial-resolution Normalized Difference Vegetation Index(NDVI)synthesized through the Spatial and Temporal Non-Local Filter-based Fusion Model(STNLFFM),we are able to capture the NDVI time profiles of grassland types,accurately extract vegetation phenological information within the year,and further enhance the temporal resolution.(3)The integration of multi-seasonal spectral,polarization,and phenological characteristics significantly improves the classification accuracy of grassland types.The overall accuracy reaches 82.61%,with a kappa coefficient of 0.79.Compared to using only multi-seasonal spectral features,the accuracy and kappa coefficient have improved by 15.94%and 0.19,respectively.Notably,the accuracy improvement of the gently sloping steppe is the highest,exceeding 38%.(4)Sandy grassland is the most widespread in the study area,and the growth season of grassland vegetation mainly occurs from May to September.The sandy meadow exhibits a longer growing season compared with typical grassland and meadow,and the distinct differences in phenological characteristics contribute to the accurate identification of various grassland types.
基金Project (No. 2009ZX02038) supported by the National Science and Technology Major Project of China
文摘With the development of 3D integration technology, microsystems with vertical interconnects are attracting attention from researchers and industry applications. Basic elements of integrated passive devices （IPDs）, including inductors, capacitors, and resistors, could dramatically save the tbotprint of the system, optimize the form factor, and improve the performance of radio frequency （RF） systems. In this paper, IPDs using thin film built-up technology are introduced, and the design and characterization of coplanar waveguides （CPWs）, inductors, and capacitors are presented.
基金Bundesministerium fur Arbeit und Wirtschaft(CDL-SMBS)Osterreichische Nationalstiftung fir Forschung,Technologie und Entwicklung(CDL-SMBS)Christian Doppler Forschungsgesellschaft(CDL-SMBS).
文摘Phase is an intrinsic property of light,and thus a crucial parameter across numerous applications in modern optics.Various methods exist for measuring the phase of light,each presenting challenges and limitationsfrom the mechanical stability requirements of free-space interferometers to the computational complexity usually associated with methods based on spatial light modulators.Here,we utilize a passive photonic integrated circuit to spatially probe phase and intensity distributions of free-space light beams.Phase information is encoded into intensity through a set of passive on-chip interferometers,allowing conventional detectors to retrieve the phase profile of light through single-shot intensity measurements.Furthermore,we use silicon nitride as a material platform for the waveguide architecture,facilitating multi-spectral utilization in the visible spectral range.Our approach for fast,multi-spectral,and spatially resolved measurement of intensity and phase enables a wide variety of potential applications,ranging from microscopy to free-space optical communication.
基金Supported by the National Basic Research and Development (973) Program of China(2012CB955301)National Natural Science Foundation of China(41305026,41075021,41305027)Fundamental Research Fund for the Central Universities of China(LZUJBKY-2013-104)
文摘In this paper,the methods to detect dust based on passive and active measurements from satellites have been summarized.These include the visible and infrared（VIR） method,thermal infrared（TIR） method,microwave polarized index（MPI） method,active lidar-based method,and combined lidar and infrared measurement（CLIM） method.The VIR method can identify dust during daytime.Using measurements at wavelengths of 8.5,11.0,and 12.0 fan,the TIR method can distinguish dust from other types of aerosols and cloud,and identify the occurrence of dust over bright surfaces and during night.Since neither the VIR nor the TIR method can penetrate ice clouds,they cannot detect dust beneath ice clouds.The MPI method,however,can identify about 85%of the dust beneath ice clouds.Meanwhile,the active lidar-based method,which uses the Cloud-Aerosol Lidar with Orthogonal Polarization（CALIOP） data and five-dimensional probability distribution functions,can provide very high-resolution vertical profiles of dust aerosols.Nonetheless,as the signals from dense dust and thin clouds are similar in the CALIOP measurements,the lidar-based method may fail to distinguish between them,especially over dust source regions.To address this issue,the CLIM method was developed,which takes the advantages of both TIR measurements（to discriminate between ice cloud and dense dust layers） and lidar measurements（to detect thin dust and water cloud layers）.The results obtained by using the new CLIM method show that the ratio of dust misclassification has been significantly reduced.Finally,a concept module for an integrated multi-satellites dust detection system was proposed to overcome some of the weaknesses inherent in the single-sensor dust detection.
文摘A broadband monolithic linear single pole, eight throw （SP8T） switch has been fabricated in 180 nm thin film silicon-on-insulator （SOI） CMOS technology with a quad-band GSM harmonic filter in integrated passive devices （IPD） technology, which is developed for cellular applications. The antenna switch module （ASM） features 1.2 dB insertion loss with filter on 2G bands and 0.4 dB insertion loss in 3G bands, less than -45 dB isolation and maximum -103 dB intermodulation distortion for mobile front ends by applying distributed architecture and adaptive supply voltage generator.
基金supported by the National Key R & D Program of China (No.2022YFB3206900)National Natural Science Foundation of China (No.32202914+4 种基金No.32172955)the Open Innovation Fund of Changjiang Survey Planning Design and Research Co., Ltd (No. CX2021K03)the Scientific Instrument Developing Project of the Chinese Academy of Sciences (No.YJKYYQ20190055)the Special Program for the Institute of National Parks of the Chinese Academy Sciences (No.KFJ-STS-ZDTP-2021-003)the CAS President’s International Fellowship Initiative (PIFI) (No.2023DC0002).
文摘Fish passage facilities are constructed worldwide to enable fish to pass anthropogenic obstacles (i.e., dams) and re-establish river connectivity. The construction of these facilities involves sophisticated engineering designed to attract fish and enable passage. The behavior of fish encountering these structures, particularly in long vertical slot fishways, has been poorly studied. This study was conducted on the Daduhe River in Southwest China to quantify the upstream passage efficiency and performance of tagged Schizothorax davidi in different sections of a long vertical slot fishway spanning 1228.3 m. The overall passage efficiency was 13% although the passage efficiency in seven sections (A0-A1, A1-A2, A2-A3, A3-A4, A4-A5, A5-A6, A6-A7) ranged from 43% to 100% reflecting differences in slope among sections. The highest passage efficiency was documented in rest pool sections with a slope of 0 (A3–A4, 100% and A6–A7, 100%) and during passage through the dam itself (A5–A6, 90.0%). The lowest passage efficiency was section A2–A3, where a garbage interception facility affected passage efficiency. Average transit time from A0 to A7 was 85.2 h and ranged from 8.8 to 237.6 h. Transit speed varied over various sections. The first section (i.e., A0–A1) had slow transit speeds which presumably was influenced by acclimation and recovery from tag implantation. After this, the transit speed had a slight increase but decreased again. Additionally, more than half (5 out of 9 fish) of the fish fell back after reaching the most upstream section and reascended the fishway which tripled the total passage time for those individuals. No significant diel activity rhythms were observed, but a strong bimodal distribution was noted in fish transit time when passing the first monitoring site. Cox-proportional hazards model showed that transit time was negatively correlated with body size but positively correlated with water level and water temperature. Our study provides valuable insights into activity when passing through a long fishway, which can inform design of fishway structures and operational patterns to improve upstream passage efficiency. Specifically, we recommend increasing the number of resting pools and maintaining appropriate water levels to reduce transit time and fallback frequency in long fishways.
基金supported by the National Key Basic Research Program of China(No.2014CB339901)
文摘The GaAs-based TF-IPD fabrication process and equivalent lumped element circuit are utilized to re- duce the circuit size for double-section Wilkinson power divider. Ultimately the dimension of the proposed S-band power divider is reduced to 1.03 × 0.98 mm2. Its measured results show an operating fractional bandwidth of 54%, and return losses and isolation of greater than 20 dB. In addition the excess insertion loss is less than 1.1 dB. More- over the good features contain amplitude and phase equilibrium with the values of better than 0.03 dB and 1.5° separately. This miniaturized power divider could be widely used in RF/microwave circuit systems.
基金supported by the National Basic Research Program of China(No.2009CB326206)the National Natural Science Foundation of China(Nos.61076111,50975266)+2 种基金the Key Laboratory Fund of China(No.9140C1204040909)the Graduate Innovation Project of China (No.20103083)the Fund for Top Young Academic Leaders of Higher Learning Institutions of Shanxi(TYAL),China
文摘An ultra-small integrated photonic circuit has been proposed,which incorporates a high-quality-factor passive micro-ring resonator（MR） linked to a vertical grating coupler on a standard silicon-on-insulator（SOI） substrate.The experimental results demonstrate that the MR propagation loss is 0.532 dB/cm with a 10μm radius ring resonator,the intrinsic quality factor is as high as 202.000,the waveguide grating wavelength response curve is a 1 dB bandwidth of 40 nm at 1540 nm telecommunication wavelengths,and the measured fiber-to-fiber coupling loss is 10 dB.Furthermore,the resonator wavelength temperature dependence of the 450 nm wide micro-ring resonator is 54.1 pm/℃.Such vertical grating coupler and low loss MR-integrated components greatly promote a key element in biosensors and high-speed interconnect communication applications.
