Cascaded H-bridge inverter(CHBI) with supercapacitors(SCs) and dc-dc stage shows significant promise for medium to high voltage energy storage applications. This paper investigates the voltage balance of capacitors wi...Cascaded H-bridge inverter(CHBI) with supercapacitors(SCs) and dc-dc stage shows significant promise for medium to high voltage energy storage applications. This paper investigates the voltage balance of capacitors within the CHBI, including both the dc-link capacitors and SCs. Balance control over the dc-link capacitor voltages is realized by the dcdc stage in each submodule(SM), while a hybrid modulation strategy(HMS) is implemented in the H-bridge to balance the SC voltages among the SMs. Meanwhile, the dc-link voltage fluctuations are analyzed under the HMS. A virtual voltage variable is introduced to coordinate the balancing of dc-link capacitor voltages and SC voltages. Compared to the balancing method that solely considers the SC voltages, the presented method reduces the dc-link voltage fluctuations without affecting the voltage balance of SCs. Finally, both simulation and experimental results verify the effectiveness of the presented method.展开更多
Ultrasensitive nanomechanical instruments,e.g.atomic force microscopy(AFM),can be used to perform delicate biomechanical measurements and reveal the complex mechanical environment of biological processes.However,these...Ultrasensitive nanomechanical instruments,e.g.atomic force microscopy(AFM),can be used to perform delicate biomechanical measurements and reveal the complex mechanical environment of biological processes.However,these instruments are limited because of their size and complex feedback system.In this study,we demonstrate a miniature fiber optical nanomechanical probe(FONP)that can be used to detect the mechanical properties of single cells and in vivo tissue measurements.A FONP that can operate in air and in liquids was developed by programming a microcantilever probe on the end face of a single-mode fiber using femtosecond laser two-photon polymerization nanolithography.To realize stiffness matching of the FONP and sample,a strategy of customizing the microcantilever’s spring constant according to the sample was proposed based on structure-correlated mechanics.As a proof-of concept,three FONPs with spring constants varying from 0.421 N m^(−1)to 52.6 N m^(−1)by more than two orders of magnitude were prepared.The highest microforce sensitivity was 54.5 nmμN^(−1)and the detection limit was 2.1 nN.The Young’s modulus of heterogeneous soft materials,such as polydimethylsiloxane,muscle tissue of living mice,onion cells,and MCF-7 cells,were successfully measured,which validating the broad applicability of this method.Our strategy provides a universal protocol for directly programming fiber-optic AFMs.Moreover,this method has no special requirements for the size and shape of living biological samples,which is infeasible when using commercial AFMs.FONP has made substantial progress in realizing basic biological discoveries,which may create new biomedical applications that cannot be realized by current AFMs.展开更多
Optical fiber technology has changed the world by enabling extraordinary growth in world-wide communications and sensing.The rapid development and wide deployment of optical fiber sensors are driven by their excellent...Optical fiber technology has changed the world by enabling extraordinary growth in world-wide communications and sensing.The rapid development and wide deployment of optical fiber sensors are driven by their excellent sensing performance with outstanding flexibility,functionality,and versatility.Notably,the research on specialty optical fibers is playing a critical role in enabling and proliferating the optical fiber sensing applications.This paper overviews recent developments in specialty optical fibers and their sensing applications.The specialty optical fibers are reviewed based on their innovations in special structures,special materials,and technologies to realize lab in/on a fiber.An overview of sensing applications in various fields is presented.The prospects and emerging research areas of specialty optical fibers are also discussed.展开更多
Optical fibers are typically used in telecommunications services for data transmission,where the use of fiber tags is essential to distinguish between the different transmission fibers or channels and thus ensure the ...Optical fibers are typically used in telecommunications services for data transmission,where the use of fiber tags is essential to distinguish between the different transmission fibers or channels and thus ensure the working functionality of the communication system.Traditional physical entity marking methods for fiber labeling are bulky,easily confused,and,most importantly,the label information can be accessed easily by all potential users.This work proposes an encrypted optical fiber tag based on an encoded fiber Bragg grating(FBG)array that is fabricated using a point-by-point femtosecond laser pulse chain inscription method.Gratings with different resonant wavelengths and reflectivities are realized by adjusting the grating period and the refractive index modulations.It is demonstrated that a binary data sequence carried by a fiber tag can be inscribed into the fiber core in the form of an FBG array,and the tag data can be encrypted through appropriate design of the spatial distributions of the FBGs with various reflection wavelengths and reflectivities.The proposed fiber tag technology can be used for applications in port identification,encrypted data storage,and transmission in fiber networks.展开更多
Status epilepticus was induced via intraperitoneal injection of lithium-pilocarpine.The inhibitory effects of propofol on status epilepticus in rats were judged based on observation of behavior,electroencephalography ...Status epilepticus was induced via intraperitoneal injection of lithium-pilocarpine.The inhibitory effects of propofol on status epilepticus in rats were judged based on observation of behavior,electroencephalography and 24-hour survival rate.Propofol(12.5-100 mg/kg) improved status epilepticus in a dose-dependent manner,and significantly reduced the number of deaths within 24 hours of lithium-pilocarpine injection.Western blot results showed that,24 hours after induction of status epilepticus,the levels of N-methyl-D-aspartate receptor 2A and 2B subunits were significantly increased in rat cerebral cortex and hippocampus.Propofol at 50 mg/kg significantly suppressed the increase in N-methyl-D-aspartate receptor 2B subunit levels,but not the increase in N-methyl-D-aspartate receptor 2A subunit levels.The results suggest that propofol can effectively inhibit status epilepticus induced by lithium-pilocarpine.This effect may be associated with downregulation of N-methyl-D-aspartate receptor 2B subunit expression after seizures.展开更多
The Dashuigou tellurium(Te) deposit in Shimian city, Sichuan Province is the only known independent Te ore deposit in China. Samples were collected by1/50,000 stream sediment survey and analyzed by inductively coupled...The Dashuigou tellurium(Te) deposit in Shimian city, Sichuan Province is the only known independent Te ore deposit in China. Samples were collected by1/50,000 stream sediment survey and analyzed by inductively coupled plasma–mass spectrometry, X-ray fluorescence spectrometry, emission spectrometry, and atomic absorption spectroscopy. An ore prospecting model for the Dashuigou Te deposit was then established. In the Dashuigou area, bismuth(Bi), Te, and gold(Au) concentrations in stream sediment samples displayed weak-positive anomalies, while silver(Ag) displayed a weaknegative anomaly. Bi, Te, Ag, and Au anomalies are regarded as indicators of Te deposits; the greater the ratio of Te+Bi/Au+Ag, the larger the possibility of an independent tellurobismuthite deposit. The ratio calculated from our samples is 7.288. Five locations were identified for prospecting for Te minerals by this model, including the northern part of the Dashuigou Te deposit, Majiagou,Tizigou, southeastern Miaoping, and northern Baishuihe.These five regions are within the Dashuigou dome anticline, the exposed strata of which are controlled by tracing the tensile shear fracture; the metallogenic geological conditions and geochemical characteristics are the same as those of the known Dashuigou Te deposit. Already, Te–Bi veins have been found in some of these areas.展开更多
A series of(Y_(1-y), Gdy)_(0.95-x)(P_y, V_(1-y))O_4 :0.05Eu^(3+), xBi^(3+)+phosphors have been successfully prepared by a subsection method. The crystal structure, surface morphology and luminescence properties were i...A series of(Y_(1-y), Gdy)_(0.95-x)(P_y, V_(1-y))O_4 :0.05Eu^(3+), xBi^(3+)+phosphors have been successfully prepared by a subsection method. The crystal structure, surface morphology and luminescence properties were investigated. It was found that the sintered samples crystallized in a tetragonal crystal system with space group I_(41)/amd(a = b = 0.7119 nm, c = 0.6290 nm). The products presented rod-like morphology with length of 100-150 nm and width of 50-100 nm. A maximum peak at 619 nm(~5D_0 →~7F_2) was observed in emission spectrum of the phosphors. It was also found that co-doping of Bi^(3+)+, P5+and Gd^(3+)ions into YVO_4:Eu^(3+)can not only made the right edge of the excitation band shift to the long-wavelength region, but also increased the emission intensity at 619 nm sharply and decreased the lifetime of fluorescence decay. These results may expand the application scope of the phosphors.展开更多
In this paper,a hybrid electronic noses’system(HENS)based on MOS-SAW detection units intended for lung cancer diagnosis is proposed.The MOS gas sensors are used to detect the VOC molecules with low molecular weight(L...In this paper,a hybrid electronic noses’system(HENS)based on MOS-SAW detection units intended for lung cancer diagnosis is proposed.The MOS gas sensors are used to detect the VOC molecules with low molecular weight(LMW),and the SAW sensors are adopted for the detection of VOC with high molecular weight(HMW).Thus,the novel combination of these two kinds of gas sensors provides higher sensitivities to more of VOC species in breath than that of using only a single kind of sensor.The signals from MOS-SAW detection units are then recognized by a multi-model diagnosis method.Applying four algorithms,six models were established for diagnosis and tested by leave-one-out cross-validation method.The model by artificial neural network(ANN)was selected as the best model to analyze breath samples.89 clinical samples were tested with MOS-SAW ANN diagnostic model,which takes the features derived from both the MOS and SAW sensors.It shows the highest sensitivity of 93.62%,and the highest selectivity of 83.37%.The study shows that,promisingly,our HENS is effective during screening of lung cancer patients,especially among the people of high risk.展开更多
A method of identifying positron/electron species from the cosmic rays was studied in the DArk Matter Particle Explorer(DAMPE)experiment.As there is no onboard magnet on the satellite,the different features imposed by...A method of identifying positron/electron species from the cosmic rays was studied in the DArk Matter Particle Explorer(DAMPE)experiment.As there is no onboard magnet on the satellite,the different features imposed by the geomagnetic field on these two species were exploited for the particle identification.Application of this method to the simulation of on-orbit electrons/positrons/protons and the real flight data proves that separately measuring the CR positrons/electrons with DAMPE is feasible,though limited by the field of view for the present observation data.Further analysis on the positron flux with this method can be expected in the future.展开更多
In order to explore a new mulch-free maize planting mode and the best seedling age for maize transplantation in Shanxi early mature area,a field experiment was carried out using completely randomized block design. Tak...In order to explore a new mulch-free maize planting mode and the best seedling age for maize transplantation in Shanxi early mature area,a field experiment was carried out using completely randomized block design. Taking mulch based direct sowing as the control group,effects of transplantation in different seedling age on maize growing process,plant height,yield and composition factors of maize were analyzed.Results indicate that growing process of maize seedlings transplanted in different seedling age is slightly slower than the control group. Transplantation has the effect of reducing plant height. Although the yield of transplanted maize in different seedling age is lower than the control group. Besides,with the growth of seedling age of transplantation,the gap is widening. However,it is expected to realize mulch-free maize planting by transplantation in Shanxi early mature area. The yield of maize transplanted in two-leaf seedling age is not significantly different from the control group,and the yield is only 9% lower than the mulch-based direct sowing( CK). In conclusion,two-leaf period is the best seedling transplantation age for maize in Shanxi early mature area in this experiment condition.展开更多
In order to explore a new mulch-free maize planting mode and the best seedling age for maize transplantation in Shanxi early mature area,a field experiment was carried out using completely randomized block design.Taki...In order to explore a new mulch-free maize planting mode and the best seedling age for maize transplantation in Shanxi early mature area,a field experiment was carried out using completely randomized block design.Taking mulch-based direct sowing as the control group,effects of transplantation in different stage on maize growing process,plant height,three-ear leaf area in mature period,and yield and composition factors of maize were studied.Results indicate that growing process of maize seedlings transplanted in every stage is slightly slower than the control group.Transplantation has effect of reducing plant height and three-ear leaf area in mature period.There was no significant difference between the yield of maize transplanted on May 1st and the control group,and the yield declined only by 7% compared with mulch-based direct sowing(CK).Damages to maize seedlings by the local late frost must be noticed when maize is planted by the method of mulch-free transplantation in early mature area.Transplanting the seedlings earlier after the late frost is deemed as an appropriate period in this area.展开更多
Hydrogel-based triboelectric nanoge nerator(TENG)has a promising applied prospect in wearable electronic devices.However,its low performance,poor stability,insufficient recyclability and inferior self-healing seriousl...Hydrogel-based triboelectric nanoge nerator(TENG)has a promising applied prospect in wearable electronic devices.However,its low performance,poor stability,insufficient recyclability and inferior self-healing seriously hinder its development.Herein,we report a robust route to a liquid metal(LM)/polyvinyl alcohol(PVA)hydrogel-based TENG(LP-TENG).Owing to the intrinsically liquid feature of conductive LM within the flexible PVA hydrogel,the as-prepared LP-TENG exhibited comprehensiye advantages of adaptability,biocompatibility,outstanding electrical performance,superior stability,recyclability and diverse applications,which were unattainable by traditional systems.Concretely,the LP-TENG delivered appealing open circuit voltage of 250 V,short circuit current of 4μA and transferred charge of 120 nC with high stability,outperforming most advanced TENG systems.The LP-TENG was successfully employed for versatile applications with multifunctionality,including human motion detection,handwriting recognition,energy collection,message transmission and human-machine interaction.This work presents significant prospects for crafting advanced materials and devices in the fields of wearable electronics,flexible skin and smart robots.展开更多
An enormous number of wireless sensing nodes(WSNs)are of great significance for the Internet of Things(IoT).It is tremendously prospective to realize the in-situ power supply of WSNs by harvesting unutilized mechanica...An enormous number of wireless sensing nodes(WSNs)are of great significance for the Internet of Things(IoT).It is tremendously prospective to realize the in-situ power supply of WSNs by harvesting unutilized mechanical vibration energy.A harmonic silicone rubber triboelectric nanogenerator(HSR-TENG)is developed focusing on ubiquitous constant working frequency machinery.The unique design of the strip serving as a flexible resonator realizes both soft contact and high and broadband output.The significant factors influencing the 1^(st)-order vibration mode of the strip are developed for realizing the harmonic frequency adaptation to external vibration.The surface treatment of the strip improves the output performance of HSR-TENG by 49.1%as well as eliminates the adhesion effect.The HSR-TENG is able to achieve a voltage output bandwidth of 19 Hz under a vibration strength of 3.0,showing its broadband capability.The peak power density of 153.9 W/m^(3)is achieved and 12×0.5 W light-emitting diodes(LEDs)are successfully illuminated by the HSR-TENG.It can continuously power a temperature sensor by harvesting the actual compressor vibration energy.In brief,the HSR-TENG provides a promising way for constant frequency vibration energy harvesting,so as to achieve in-situ power supply for the WSNs in the vicinity.展开更多
The most important optical component in an optical fiber endoscope is its objective lens.To achieve a high imaging performance level,the development of an ultra-compact objective lens is thus the key to an ultra-thin ...The most important optical component in an optical fiber endoscope is its objective lens.To achieve a high imaging performance level,the development of an ultra-compact objective lens is thus the key to an ultra-thin optical fiber endoscope.In this work,we use femtosecond laser 3D printing to develop a series of micro objective lenses with different optical designs.The imaging resolution and field-of-view performances of these printed micro objective lenses are investigated via both simulations and experiments.For the first time,multiple micro objective lenses with different fields of view are printed on the end face of a single imaging optical fiber,thus realizing the perfect integration of an optical fiber and objective lenses.This work demonstrates the considerable potential of femtosecond laser 3D printing in the fabrication of micro-optical systems and provides a reliable solution for the development of an ultrathin fiber endoscope.展开更多
基金supported in part by the CAS Project for Young Scientists in Basic Research under Grant No. YSBR-045the Youth Innovation Promotion Association CAS under Grant 2022137the Institute of Electrical Engineering CAS under Grant E155320101。
文摘Cascaded H-bridge inverter(CHBI) with supercapacitors(SCs) and dc-dc stage shows significant promise for medium to high voltage energy storage applications. This paper investigates the voltage balance of capacitors within the CHBI, including both the dc-link capacitors and SCs. Balance control over the dc-link capacitor voltages is realized by the dcdc stage in each submodule(SM), while a hybrid modulation strategy(HMS) is implemented in the H-bridge to balance the SC voltages among the SMs. Meanwhile, the dc-link voltage fluctuations are analyzed under the HMS. A virtual voltage variable is introduced to coordinate the balancing of dc-link capacitor voltages and SC voltages. Compared to the balancing method that solely considers the SC voltages, the presented method reduces the dc-link voltage fluctuations without affecting the voltage balance of SCs. Finally, both simulation and experimental results verify the effectiveness of the presented method.
基金supported by the National Natural Science Foundation of China(NSFC)(62122057,62075136,62175165)Natural Science Foundation of Guangdong Province(2022B1515120061,2019B1515120042)Science and Technology Innovation Commission of Shenzhen(RCYX20200714114524139,JCYJ20200109114001806).
文摘Ultrasensitive nanomechanical instruments,e.g.atomic force microscopy(AFM),can be used to perform delicate biomechanical measurements and reveal the complex mechanical environment of biological processes.However,these instruments are limited because of their size and complex feedback system.In this study,we demonstrate a miniature fiber optical nanomechanical probe(FONP)that can be used to detect the mechanical properties of single cells and in vivo tissue measurements.A FONP that can operate in air and in liquids was developed by programming a microcantilever probe on the end face of a single-mode fiber using femtosecond laser two-photon polymerization nanolithography.To realize stiffness matching of the FONP and sample,a strategy of customizing the microcantilever’s spring constant according to the sample was proposed based on structure-correlated mechanics.As a proof-of concept,three FONPs with spring constants varying from 0.421 N m^(−1)to 52.6 N m^(−1)by more than two orders of magnitude were prepared.The highest microforce sensitivity was 54.5 nmμN^(−1)and the detection limit was 2.1 nN.The Young’s modulus of heterogeneous soft materials,such as polydimethylsiloxane,muscle tissue of living mice,onion cells,and MCF-7 cells,were successfully measured,which validating the broad applicability of this method.Our strategy provides a universal protocol for directly programming fiber-optic AFMs.Moreover,this method has no special requirements for the size and shape of living biological samples,which is infeasible when using commercial AFMs.FONP has made substantial progress in realizing basic biological discoveries,which may create new biomedical applications that cannot be realized by current AFMs.
基金We are grateful for financial supports from Special Funds for the Major Fields of Colleges and Universities by the Department of Education of Guangdong Province(2021ZDZX1023)Natural Science Foundation of Guangdong Province(No.2022A1515011434)+4 种基金Stable Support Program for Higher Education Institutions from Shenzhen Science,Technology&Innovation Commission(20200925162216001)Guangdong Basic and Applied Basic Research Foundation(2021B1515120013)Open Fund of State Key Laboratory of Information Photonics and Optical Communications(Beijing University of Posts and Telecommunications,No.IPOC2020A002)The Open Projects Foundation of State Key Laboratory of Optical Fiber and Cable Manufacture Technology(No.SKLD2105)General Program of Shenzhen Science,Technology&Innovation Commission(JCYJ20220530113811026).
文摘Optical fiber technology has changed the world by enabling extraordinary growth in world-wide communications and sensing.The rapid development and wide deployment of optical fiber sensors are driven by their excellent sensing performance with outstanding flexibility,functionality,and versatility.Notably,the research on specialty optical fibers is playing a critical role in enabling and proliferating the optical fiber sensing applications.This paper overviews recent developments in specialty optical fibers and their sensing applications.The specialty optical fibers are reviewed based on their innovations in special structures,special materials,and technologies to realize lab in/on a fiber.An overview of sensing applications in various fields is presented.The prospects and emerging research areas of specialty optical fibers are also discussed.
基金supported by the National Natural Science Foundation of China(62122057,62075136,62105217,62205221,62205222)the Basic and Applied Basic Research Foundation of Guangdong Province(2022B1515120061)Shenzhen Science and Technology Program(Shenzhen Key Laboratory of Ultrafast Laser Micro/Nano Manufacturing ZDSYS20220606100405013,RCYX20200714114524139,JCYJ20200109114001806)。
文摘Optical fibers are typically used in telecommunications services for data transmission,where the use of fiber tags is essential to distinguish between the different transmission fibers or channels and thus ensure the working functionality of the communication system.Traditional physical entity marking methods for fiber labeling are bulky,easily confused,and,most importantly,the label information can be accessed easily by all potential users.This work proposes an encrypted optical fiber tag based on an encoded fiber Bragg grating(FBG)array that is fabricated using a point-by-point femtosecond laser pulse chain inscription method.Gratings with different resonant wavelengths and reflectivities are realized by adjusting the grating period and the refractive index modulations.It is demonstrated that a binary data sequence carried by a fiber tag can be inscribed into the fiber core in the form of an FBG array,and the tag data can be encrypted through appropriate design of the spatial distributions of the FBGs with various reflection wavelengths and reflectivities.The proposed fiber tag technology can be used for applications in port identification,encrypted data storage,and transmission in fiber networks.
基金supported by the One Hundred Talent Program of CASthe National Natural Science Foundation of China Petroleum & Chemical Corporation Joint Fund(U1662129)+1 种基金the National Natural Science Foundation of China(91434203)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(QYZDY-SSW-JSC011)~~
基金supported by National Natural Science Foundation of China,No. 30500482
文摘Status epilepticus was induced via intraperitoneal injection of lithium-pilocarpine.The inhibitory effects of propofol on status epilepticus in rats were judged based on observation of behavior,electroencephalography and 24-hour survival rate.Propofol(12.5-100 mg/kg) improved status epilepticus in a dose-dependent manner,and significantly reduced the number of deaths within 24 hours of lithium-pilocarpine injection.Western blot results showed that,24 hours after induction of status epilepticus,the levels of N-methyl-D-aspartate receptor 2A and 2B subunits were significantly increased in rat cerebral cortex and hippocampus.Propofol at 50 mg/kg significantly suppressed the increase in N-methyl-D-aspartate receptor 2B subunit levels,but not the increase in N-methyl-D-aspartate receptor 2A subunit levels.The results suggest that propofol can effectively inhibit status epilepticus induced by lithium-pilocarpine.This effect may be associated with downregulation of N-methyl-D-aspartate receptor 2B subunit expression after seizures.
基金supported by the Institute of Geochemistry, Chinese Academy of Sciences (03JY029-027-1)Sichuan Geological Survey (12120113051400)the State Key Laboratory of Ore Deposit Geochemistry, Chinese Academy of Sciences for its open program funding
文摘The Dashuigou tellurium(Te) deposit in Shimian city, Sichuan Province is the only known independent Te ore deposit in China. Samples were collected by1/50,000 stream sediment survey and analyzed by inductively coupled plasma–mass spectrometry, X-ray fluorescence spectrometry, emission spectrometry, and atomic absorption spectroscopy. An ore prospecting model for the Dashuigou Te deposit was then established. In the Dashuigou area, bismuth(Bi), Te, and gold(Au) concentrations in stream sediment samples displayed weak-positive anomalies, while silver(Ag) displayed a weaknegative anomaly. Bi, Te, Ag, and Au anomalies are regarded as indicators of Te deposits; the greater the ratio of Te+Bi/Au+Ag, the larger the possibility of an independent tellurobismuthite deposit. The ratio calculated from our samples is 7.288. Five locations were identified for prospecting for Te minerals by this model, including the northern part of the Dashuigou Te deposit, Majiagou,Tizigou, southeastern Miaoping, and northern Baishuihe.These five regions are within the Dashuigou dome anticline, the exposed strata of which are controlled by tracing the tensile shear fracture; the metallogenic geological conditions and geochemical characteristics are the same as those of the known Dashuigou Te deposit. Already, Te–Bi veins have been found in some of these areas.
基金supported by the Program for New Material Development & Application innovative Research Team of Higher Education in Chong Qing of China (Grant No. 201042)
文摘A series of(Y_(1-y), Gdy)_(0.95-x)(P_y, V_(1-y))O_4 :0.05Eu^(3+), xBi^(3+)+phosphors have been successfully prepared by a subsection method. The crystal structure, surface morphology and luminescence properties were investigated. It was found that the sintered samples crystallized in a tetragonal crystal system with space group I_(41)/amd(a = b = 0.7119 nm, c = 0.6290 nm). The products presented rod-like morphology with length of 100-150 nm and width of 50-100 nm. A maximum peak at 619 nm(~5D_0 →~7F_2) was observed in emission spectrum of the phosphors. It was also found that co-doping of Bi^(3+)+, P5+and Gd^(3+)ions into YVO_4:Eu^(3+)can not only made the right edge of the excitation band shift to the long-wavelength region, but also increased the emission intensity at 619 nm sharply and decreased the lifetime of fluorescence decay. These results may expand the application scope of the phosphors.
基金This work was supported by the National Natural Science Foundation of China(Grant No.81027003).
文摘In this paper,a hybrid electronic noses’system(HENS)based on MOS-SAW detection units intended for lung cancer diagnosis is proposed.The MOS gas sensors are used to detect the VOC molecules with low molecular weight(LMW),and the SAW sensors are adopted for the detection of VOC with high molecular weight(HMW).Thus,the novel combination of these two kinds of gas sensors provides higher sensitivities to more of VOC species in breath than that of using only a single kind of sensor.The signals from MOS-SAW detection units are then recognized by a multi-model diagnosis method.Applying four algorithms,six models were established for diagnosis and tested by leave-one-out cross-validation method.The model by artificial neural network(ANN)was selected as the best model to analyze breath samples.89 clinical samples were tested with MOS-SAW ANN diagnostic model,which takes the features derived from both the MOS and SAW sensors.It shows the highest sensitivity of 93.62%,and the highest selectivity of 83.37%.The study shows that,promisingly,our HENS is effective during screening of lung cancer patients,especially among the people of high risk.
基金supported by the Outstanding Youth Science Foundation of NSFC(Grant No.12022503)the Joint Funds of the National Natural Science Foundation of China(Grant Nos.U1738208,U1738139,U1738135 and U1738207)+2 种基金the National Natural Science Foundation of China(Grant Nos.11673021,11705197,11773085 and 11851302)the National Key Research and Development Program of China(Grant No.2016YFA0400200)Youth Innovation Promotion Association CAS(Grant No.2021450)。
文摘A method of identifying positron/electron species from the cosmic rays was studied in the DArk Matter Particle Explorer(DAMPE)experiment.As there is no onboard magnet on the satellite,the different features imposed by the geomagnetic field on these two species were exploited for the particle identification.Application of this method to the simulation of on-orbit electrons/positrons/protons and the real flight data proves that separately measuring the CR positrons/electrons with DAMPE is feasible,though limited by the field of view for the present observation data.Further analysis on the positron flux with this method can be expected in the future.
基金Supported by Doctorate research foundation of Shanxi Academy of Agricultural Sciences(YBSJJ1303)
文摘In order to explore a new mulch-free maize planting mode and the best seedling age for maize transplantation in Shanxi early mature area,a field experiment was carried out using completely randomized block design. Taking mulch based direct sowing as the control group,effects of transplantation in different seedling age on maize growing process,plant height,yield and composition factors of maize were analyzed.Results indicate that growing process of maize seedlings transplanted in different seedling age is slightly slower than the control group. Transplantation has the effect of reducing plant height. Although the yield of transplanted maize in different seedling age is lower than the control group. Besides,with the growth of seedling age of transplantation,the gap is widening. However,it is expected to realize mulch-free maize planting by transplantation in Shanxi early mature area. The yield of maize transplanted in two-leaf seedling age is not significantly different from the control group,and the yield is only 9% lower than the mulch-based direct sowing( CK). In conclusion,two-leaf period is the best seedling transplantation age for maize in Shanxi early mature area in this experiment condition.
基金Supported by Doctorate Research Foundation of Shanxi Academy of Agricultural Sciences(YBSJJ1303)
文摘In order to explore a new mulch-free maize planting mode and the best seedling age for maize transplantation in Shanxi early mature area,a field experiment was carried out using completely randomized block design.Taking mulch-based direct sowing as the control group,effects of transplantation in different stage on maize growing process,plant height,three-ear leaf area in mature period,and yield and composition factors of maize were studied.Results indicate that growing process of maize seedlings transplanted in every stage is slightly slower than the control group.Transplantation has effect of reducing plant height and three-ear leaf area in mature period.There was no significant difference between the yield of maize transplanted on May 1st and the control group,and the yield declined only by 7% compared with mulch-based direct sowing(CK).Damages to maize seedlings by the local late frost must be noticed when maize is planted by the method of mulch-free transplantation in early mature area.Transplanting the seedlings earlier after the late frost is deemed as an appropriate period in this area.
基金financially supported by the Natural Science Foundation of China(Nos.22109120,62104170 and 82202757)Zhejiang Provincial Natural Science Foundation of China(Nos.LQ21B030002 and LY23F040001)。
文摘Hydrogel-based triboelectric nanoge nerator(TENG)has a promising applied prospect in wearable electronic devices.However,its low performance,poor stability,insufficient recyclability and inferior self-healing seriously hinder its development.Herein,we report a robust route to a liquid metal(LM)/polyvinyl alcohol(PVA)hydrogel-based TENG(LP-TENG).Owing to the intrinsically liquid feature of conductive LM within the flexible PVA hydrogel,the as-prepared LP-TENG exhibited comprehensiye advantages of adaptability,biocompatibility,outstanding electrical performance,superior stability,recyclability and diverse applications,which were unattainable by traditional systems.Concretely,the LP-TENG delivered appealing open circuit voltage of 250 V,short circuit current of 4μA and transferred charge of 120 nC with high stability,outperforming most advanced TENG systems.The LP-TENG was successfully employed for versatile applications with multifunctionality,including human motion detection,handwriting recognition,energy collection,message transmission and human-machine interaction.This work presents significant prospects for crafting advanced materials and devices in the fields of wearable electronics,flexible skin and smart robots.
基金supported by the National Natural Science Foundation of China(Nos.52101345,52101400)the Scientific Research Fund of Liaoning Provincial Education Department(No.LJKZ0055)+1 种基金the Dalian Outstanding Young Scientific and Technological Talents Project(No.2021RJ11)the Open Fund of National Center for International Research of Subsea Engineering Technology and Equipment(No.3132023354).
文摘An enormous number of wireless sensing nodes(WSNs)are of great significance for the Internet of Things(IoT).It is tremendously prospective to realize the in-situ power supply of WSNs by harvesting unutilized mechanical vibration energy.A harmonic silicone rubber triboelectric nanogenerator(HSR-TENG)is developed focusing on ubiquitous constant working frequency machinery.The unique design of the strip serving as a flexible resonator realizes both soft contact and high and broadband output.The significant factors influencing the 1^(st)-order vibration mode of the strip are developed for realizing the harmonic frequency adaptation to external vibration.The surface treatment of the strip improves the output performance of HSR-TENG by 49.1%as well as eliminates the adhesion effect.The HSR-TENG is able to achieve a voltage output bandwidth of 19 Hz under a vibration strength of 3.0,showing its broadband capability.The peak power density of 153.9 W/m^(3)is achieved and 12×0.5 W light-emitting diodes(LEDs)are successfully illuminated by the HSR-TENG.It can continuously power a temperature sensor by harvesting the actual compressor vibration energy.In brief,the HSR-TENG provides a promising way for constant frequency vibration energy harvesting,so as to achieve in-situ power supply for the WSNs in the vicinity.
基金primary financial support from the Natural Science Foundation of Beijing (2222009)the National Key R&D Program of China (2022YFE0128700,2021YFA1200102,and 2021YFA1200101)the National Natural Science Foundation of China (22173050,21727806,22150013,and 21933001)。
基金This work was supported by Shenzhen Science and Technology Program(RCYX20200714114524139,Shenzhen Key Laboratory of Ultrafast Laser Micro/Nano Manufacturing ZDSYS20220606100405013)Natural Science Foundation of Guangdong Province(2022B1515120061)National Natural Science Foundation of China(62122057,62075136).
文摘The most important optical component in an optical fiber endoscope is its objective lens.To achieve a high imaging performance level,the development of an ultra-compact objective lens is thus the key to an ultra-thin optical fiber endoscope.In this work,we use femtosecond laser 3D printing to develop a series of micro objective lenses with different optical designs.The imaging resolution and field-of-view performances of these printed micro objective lenses are investigated via both simulations and experiments.For the first time,multiple micro objective lenses with different fields of view are printed on the end face of a single imaging optical fiber,thus realizing the perfect integration of an optical fiber and objective lenses.This work demonstrates the considerable potential of femtosecond laser 3D printing in the fabrication of micro-optical systems and provides a reliable solution for the development of an ultrathin fiber endoscope.