The latest advancements in computer vision and deep learning(DL)techniques pave the way to design novel tools for the detection and monitoring of forestfires.In this view,this paper presents an intelligent wild forestfi...The latest advancements in computer vision and deep learning(DL)techniques pave the way to design novel tools for the detection and monitoring of forestfires.In this view,this paper presents an intelligent wild forestfire detec-tion and alarming system using deep learning(IWFFDA-DL)model.The pro-posed IWFFDA-DL technique aims to identify forestfires at earlier stages through integrated sensors.The proposed IWFFDA-DL system includes an Inte-grated sensor system(ISS)combining an array of sensors that acts as the major input source that helps to forecast thefire.Then,the attention based convolution neural network with bidirectional long short term memory(ACNN-BLSTM)model is applied to examine and identify the existence of danger.For hyperpara-meter tuning of the ACNN-BLSTM model,the bacterial foraging optimization(BFO)algorithm is employed and thereby enhances the detection performance.Finally,when thefire is detected,the Global System for Mobiles(GSM)modem transmits messages to the authorities to take required actions.An extensive set of simulations were performed and the results are investigated interms of several aspects.The obtained results highlight the betterment of the IWFFDA-DL techni-que interms of various measures.展开更多
The novel integrated circuit (IC) temperature sensor presented in this paper works similarly as a two terminal Zener, has breakdown voltage directly proportional to Kelvin temperature at 10 mV/℃, with typical error ...The novel integrated circuit (IC) temperature sensor presented in this paper works similarly as a two terminal Zener, has breakdown voltage directly proportional to Kelvin temperature at 10 mV/℃, with typical error of less than ±1.0℃ over a temperature range from -50℃ to +125℃. In addition to all the features that conventional IC temperature sensors have, the new device also has very low static power dissipation ( 0.5 mW ) , low output impedance ( less than 1Ω), excellent stability, high reproducibility, and high precision. The sensor's circuit design and layout are discussed in detail. Applications of the sensor include almost any type of temperature sensing over the range of -50℃-+125℃. The low impedance and linear output of the device make interfacing the readout or control circuitry especially easy. Due to the excellent performance and low cost of this sensor, more applications of the sensor over wide temperature range are expected.展开更多
Pure inertial navigation system(INS) has divergent localization errors after a long time. In order to compensate the disadvantage, wireless sensor network(WSN) associated with the INS was applied to estimate the mobil...Pure inertial navigation system(INS) has divergent localization errors after a long time. In order to compensate the disadvantage, wireless sensor network(WSN) associated with the INS was applied to estimate the mobile target positioning. Taking traditional Kalman filter(KF) as the framework, the system equation of KF was established by the INS and the observation equation of position errors was built by the WSN. Meanwhile, the observation equation of velocity errors was established by the velocity difference between the INS and WSN, then the covariance matrix of Kalman filter measurement noise was adjusted with fuzzy inference system(FIS), and the fuzzy adaptive Kalman filter(FAKF) based on the INS/WSN was proposed. The simulation results show that the FAKF method has better accuracy and robustness than KF and EKF methods and shows good adaptive capacity with time-varying system noise. Finally, experimental results further prove that FAKF has the fast convergence error, in comparison with KF and EKF methods.展开更多
The origin of the piezoelectric effect of GaAs is discussed in some detail.TheGa atoms are negatively charged and As atoms positively charged.The piezoelectric con-stant tensors for arbitrarily oriented GaAs have been...The origin of the piezoelectric effect of GaAs is discussed in some detail.TheGa atoms are negatively charged and As atoms positively charged.The piezoelectric con-stant tensors for arbitrarily oriented GaAs have been obtained.It is verified that for nor-mal stress when the GaAs samples are oriented in the 〈111〉 direction the maximumpiezoelectric effect occurs.As far as the piezoelectric properties and fabrication technologyare concerned,〈100〉 oriented GaAs substratcs are fit for the force sensors.展开更多
This paper reports on the fabrication and sensing characteristics of Polyimide-based humidity sensor,based on that,a new integrated circuit of humidity measurement has been designed.It is a novel capacitive-type syste...This paper reports on the fabrication and sensing characteristics of Polyimide-based humidity sensor,based on that,a new integrated circuit of humidity measurement has been designed.It is a novel capacitive-type systems on a chip structure using the MEMS process.The results show that the new sensor presents sensing characteristics over a humidity range from 10%~70% RH at 20℃,and the sensor is able to fabricated together with ICs technology.The result shows that integration of humidity sensor with integrated circuit of humidity measurement is considerably easier when they are built in sensing groove.The appeal of a new structure like this brings the possibility of applications that would require the flexibility of simple screen printing.展开更多
taking the bucket of multi function earth drill as an example, combining with the conception of multi sensor integration and data fusion, adopting the terrene column chart and digging torque formula as control depende...taking the bucket of multi function earth drill as an example, combining with the conception of multi sensor integration and data fusion, adopting the terrene column chart and digging torque formula as control dependence, the detecting method of the earth drill’s working state is introduced. Multi sensor data fusion is done with the aid of BP neural network in Matlab. The data to be interfused are pre processed and the program of simulation and “point checking” is given.展开更多
We describe and experimentally demonstrate a measuring technique for Mach–Zehnder interferometer(MZI)based integrated photonic biochemical sensors. Our technique is based on the direct measurement of phase changes be...We describe and experimentally demonstrate a measuring technique for Mach–Zehnder interferometer(MZI)based integrated photonic biochemical sensors. Our technique is based on the direct measurement of phase changes between the arms of the MZI, achieved by signal modulation on one of the arms of the interferometer together with pseudoheterodyne detection, and it allows us to avoid the use of costly equipment such as tunable light sources or spectrum analyzers. The obtained output signal is intrinsically independent of wavelength, power variations, and global thermal variations, making it extremely robust and adequate for use in real conditions. Using a silicon-on-insulator MZI, we demonstrate the real-time monitoring of refractive index variations and achieve a detection limit of 4.1 × 10^(-6)refractive index units(RIU).展开更多
Optical simulations of GaAs/AlGaAs thin-film waveguides were performed for investigating the dependence of the modal behavior on waveguide geometry and the resulting analytical sensitivity. Simulations were performed ...Optical simulations of GaAs/AlGaAs thin-film waveguides were performed for investigating the dependence of the modal behavior on waveguide geometry and the resulting analytical sensitivity. Simulations were performed for two distinct mid-infrared wavelengths, thereby demonstrating the necessity of individually designed waveguide structures for each spectral regime of interest. Hence, the modal behavior, sensitivity, and intensity of the evanescent field were investigated via modeling studies at 1600 and 1000 cm^(-1), thereby confirming the utility of such simulations for designing mid-infrared sensors based on thin-film waveguide technology.展开更多
Integrated sensor combines multiple sensor functions into a single unit,which has the advantages of miniaturization and better application potential.However,limited by the sensing platforms of the sensor and the selec...Integrated sensor combines multiple sensor functions into a single unit,which has the advantages of miniaturization and better application potential.However,limited by the sensing platforms of the sensor and the selectivity of the sensitive film,there are still challenges to realize multi-component gas detection in one unit.Herein,a principle integration method is proposed to achieve the multi-component gas detection based on the acoustics-electricity-mechanics coupling effect.The electrical and mechanical properties of the Bi_(2)S_(3)nanobelts materials in different atmospheres indicate the possibility of realizing the principle integration.At the same time,the surface acoustic wave(SAW)sensor as a multivariable physical transducer can sense both electrical and mechanical properties.Upon exposure to 10 ppm NO_(2),NH_(3),and their mixtures,the integrated SAW gas sensor shows a 4.5 kHz positive frequency shift(acoustoelectric effect),an 11 kHz negative frequency shift(mechanics effects),and a reduced 4 kHz negative frequency shift(acoustics-electricity-mechanics coupling effect),respectively.Moreover,we realize wireless passive detection of NO_(2)and NH_(3)based on the SAW sensor.Our work provides valuable insights that can serve as a guide to the design and fabrication of single sensors offering multi-component gas detection via different gas sensing mechanisms.展开更多
Third generation DNA sequencing relies on monitoring the ionic current blockage during the DNA molecule’s threading through a nanoscale pore.It is still really tough to attain the single base discrimination on a DNA ...Third generation DNA sequencing relies on monitoring the ionic current blockage during the DNA molecule’s threading through a nanoscale pore.It is still really tough to attain the single base discrimination on a DNA strand by merely analyzing the ionic current due to speedy DNA translocation and low spatial resolution.More integrated configurations are pursued to present versatile comparative dissimilarities of the four bases by enhancing the spatial resolution within a DNA molecule translocation event,such as transverse tunneling current,local potential change,and capacitance oriented voltage resonance.In this mini review,the insight is provided into the status quo on several functionalized techniques and methodologies for DNA sequencing and furthermore concluding remark and outlook are presented.展开更多
Infrared and visible light image fusion technology is a hot spot in the research of multi-sensor fusion technology in recent years. Existing infrared and visible light fusion technologies need to register before fusio...Infrared and visible light image fusion technology is a hot spot in the research of multi-sensor fusion technology in recent years. Existing infrared and visible light fusion technologies need to register before fusion because of using two cameras. However, the application effect of the registration technology has yet to be improved. Hence, a novel integrative multi-spectral sensor device is proposed for infrared and visible light fusion, and by using the beam splitter prism, the coaxial light incident from the same lens is projected to the infrared charge coupled device (CCD) and visible light CCD, respectively. In this paper, the imaging mechanism of the proposed sensor device is studied with the process of the signals acquisition and fusion. The simulation experiment, which involves the entire process of the optic system, signal acquisition, and signal fusion, is constructed based on imaging effect model. Additionally, the quality evaluation index is adopted to analyze the simulation result. The experimental results demonstrate that the proposed sensor device is effective and feasible.展开更多
A newΣΔmodulator architecture for thermal vacuum sensor ASICs is proposed.The micro-hotplate thermal vacuum sensor fabricated by surface-micrornachining technology can detect the gas pressure from 1 to 10;Pa. The am...A newΣΔmodulator architecture for thermal vacuum sensor ASICs is proposed.The micro-hotplate thermal vacuum sensor fabricated by surface-micrornachining technology can detect the gas pressure from 1 to 10;Pa. The amplified differential output voltage signal of the sensor feeds to theΣΔmodulator to be converted into digital domain.The presentedΣΔmodulator makes use of a feed-forward path to suppress the harmonic distortions and attain high linearity.Compared with other feed-forward architectures presented before,the circuit complexity,chip area and power dissipation of the proposed architecture are significantly decreased.The correlated double sampling technique is introduced in the 1st integrator to reduce the flicker noise.The measurement results demonstrate that the modulator achieves an SNDR of 79.7 dB and a DR of 80 dB over a bandwidth of 7.8 kHz at a sampling rate of 4 MHz.The circuit has been fabricated in a 0.5μm 2P3M standard CMOS technology.It occupies an area of 5 mm;and dissipates 9 mW from a single 3 V power supply.The performance of the modulator meets the requirements of the considered application.展开更多
We report experimental realization of Raman spectra enhancement of copper phthalocyanine, using an on-chip metallic planar waveguide of the sub-millimeter scale. The oscillating ultrahigh order modes excited by the di...We report experimental realization of Raman spectra enhancement of copper phthalocyanine, using an on-chip metallic planar waveguide of the sub-millimeter scale. The oscillating ultrahigh order modes excited by the direct coupling method yield high optical intensity at resonance, which is different from the conventional strategy to create localized "hot spots." The observed excitation efficiency of the Raman signal is significantly enhanced,owing to the high Q factor of the resonant cavity. Furthermore, effective modulation of the Raman intensity is available by adjusting the polymethyl methacrylate(PMMA) thickness in the guiding layer, i.e., by tuning the light–matter interaction length. A large modulation depth is verified through the fact that 10 times variation in the enhancement factor is observed in the experiment as the PMMA thickness varies from 7 to 23 μm.展开更多
Indoor airborne bioaerosols of outdoor origin play an important role in determining the exposure of humans to bioaerosols because people spend most of their time indoors. However, there are few studies focusing on ind...Indoor airborne bioaerosols of outdoor origin play an important role in determining the exposure of humans to bioaerosols because people spend most of their time indoors. However, there are few studies focusing on indoor bioaerosols originating from outdoors. In this study, indoor versus outdoor size-resolved concentrations and particle asymmetry factors of airborne fluorescent bioaerosols in an office room were measured continuously for 6 days (144 h) using a fluorescent bioaerosol detector. The windows and door of this room were closed to ensure that there was only air infiltration; moreover, any human activities were ceased during sampling to inhibit effects of indoor sources. We focused on fine particles, since few coarse particles enter indoor environments, when windows and doors are closed. Both indoor and outdoor fluorescent bioaerosol size distributions were fit with two-mode lognormal distributions (indoor R2 = 0.935, outdoor R2 = 0.938). Asymmetry factor distributions were also fit with lognormal distributions (indoor R2 = 0.992, outdoor R2 = 0.992). Correlations between indoor and outdoor fluorescent bioaerosol concentrations show significant concentration-attenuation and a time lag during the study period. A two-parameter, semi-empirical model was used to predict concentrations of indoor fluorescent bioaerosols of outdoor origin. The measured and predicted concentrations had a linear relationship for the studied size fractions, with an R2 for all size fractions of larger than 0.83.展开更多
A heterogeneous wireless sensor network comprises a number of inexpensive energy constrained wireless sensor nodes which collect data from the sensing environment and transmit them toward the improved cluster head in ...A heterogeneous wireless sensor network comprises a number of inexpensive energy constrained wireless sensor nodes which collect data from the sensing environment and transmit them toward the improved cluster head in a coordinated way. Employing clustering techniques in such networks can achieve balanced energy consumption of member nodes and prolong the network lifetimes.In classical clustering techniques, clustering and in-cluster data routes are usually separated into independent operations. Although separate considerations of these two issues simplify the system design, it is often the non-optimal lifetime expectancy for wireless sensor networks. This paper proposes an integral framework that integrates these two correlated items in an interactive entirety. For that,we develop the clustering problems using nonlinear programming. Evolution process of clustering is provided in simulations. Results show that our joint-design proposal reaches the near optimal match between member nodes and cluster heads.展开更多
A digital still camera image processing system on a chip, different from the video camera system, is pre- sented for mobile phone to reduce the power consumption and size. A new color interpolation algorithm is propos...A digital still camera image processing system on a chip, different from the video camera system, is pre- sented for mobile phone to reduce the power consumption and size. A new color interpolation algorithm is proposed to enhance the image quality. The system can also process fixed patten noise (FPN) reduction, color correction, gamma correction, RGB/YUV space transfer, etc. The chip is controlled by sensor regis- ters by inter-integrated circuit (I2C) interface. The voltage for both the front-end analog and the pad cir- cuits is 2.8 V, and the volatge for the image signal processing is 1.8 V. The chip running under the external 13.5-MHz clock has a video data rate of 30 frames/s and the measured power dissipation is about 75 roW.展开更多
文摘The latest advancements in computer vision and deep learning(DL)techniques pave the way to design novel tools for the detection and monitoring of forestfires.In this view,this paper presents an intelligent wild forestfire detec-tion and alarming system using deep learning(IWFFDA-DL)model.The pro-posed IWFFDA-DL technique aims to identify forestfires at earlier stages through integrated sensors.The proposed IWFFDA-DL system includes an Inte-grated sensor system(ISS)combining an array of sensors that acts as the major input source that helps to forecast thefire.Then,the attention based convolution neural network with bidirectional long short term memory(ACNN-BLSTM)model is applied to examine and identify the existence of danger.For hyperpara-meter tuning of the ACNN-BLSTM model,the bacterial foraging optimization(BFO)algorithm is employed and thereby enhances the detection performance.Finally,when thefire is detected,the Global System for Mobiles(GSM)modem transmits messages to the authorities to take required actions.An extensive set of simulations were performed and the results are investigated interms of several aspects.The obtained results highlight the betterment of the IWFFDA-DL techni-que interms of various measures.
文摘The novel integrated circuit (IC) temperature sensor presented in this paper works similarly as a two terminal Zener, has breakdown voltage directly proportional to Kelvin temperature at 10 mV/℃, with typical error of less than ±1.0℃ over a temperature range from -50℃ to +125℃. In addition to all the features that conventional IC temperature sensors have, the new device also has very low static power dissipation ( 0.5 mW ) , low output impedance ( less than 1Ω), excellent stability, high reproducibility, and high precision. The sensor's circuit design and layout are discussed in detail. Applications of the sensor include almost any type of temperature sensing over the range of -50℃-+125℃. The low impedance and linear output of the device make interfacing the readout or control circuitry especially easy. Due to the excellent performance and low cost of this sensor, more applications of the sensor over wide temperature range are expected.
基金Project(2013AA06A411)supported by the National High Technology Research and Development Program of ChinaProject(CXZZ14_1374)supported by the Graduate Education Innovation Program of Jiangsu Province,ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘Pure inertial navigation system(INS) has divergent localization errors after a long time. In order to compensate the disadvantage, wireless sensor network(WSN) associated with the INS was applied to estimate the mobile target positioning. Taking traditional Kalman filter(KF) as the framework, the system equation of KF was established by the INS and the observation equation of position errors was built by the WSN. Meanwhile, the observation equation of velocity errors was established by the velocity difference between the INS and WSN, then the covariance matrix of Kalman filter measurement noise was adjusted with fuzzy inference system(FIS), and the fuzzy adaptive Kalman filter(FAKF) based on the INS/WSN was proposed. The simulation results show that the FAKF method has better accuracy and robustness than KF and EKF methods and shows good adaptive capacity with time-varying system noise. Finally, experimental results further prove that FAKF has the fast convergence error, in comparison with KF and EKF methods.
文摘The origin of the piezoelectric effect of GaAs is discussed in some detail.TheGa atoms are negatively charged and As atoms positively charged.The piezoelectric con-stant tensors for arbitrarily oriented GaAs have been obtained.It is verified that for nor-mal stress when the GaAs samples are oriented in the 〈111〉 direction the maximumpiezoelectric effect occurs.As far as the piezoelectric properties and fabrication technologyare concerned,〈100〉 oriented GaAs substratcs are fit for the force sensors.
基金This work was supported by National Natural Science Foundation of China, Under Grant No.(60676044)
文摘This paper reports on the fabrication and sensing characteristics of Polyimide-based humidity sensor,based on that,a new integrated circuit of humidity measurement has been designed.It is a novel capacitive-type systems on a chip structure using the MEMS process.The results show that the new sensor presents sensing characteristics over a humidity range from 10%~70% RH at 20℃,and the sensor is able to fabricated together with ICs technology.The result shows that integration of humidity sensor with integrated circuit of humidity measurement is considerably easier when they are built in sensing groove.The appeal of a new structure like this brings the possibility of applications that would require the flexibility of simple screen printing.
文摘taking the bucket of multi function earth drill as an example, combining with the conception of multi sensor integration and data fusion, adopting the terrene column chart and digging torque formula as control dependence, the detecting method of the earth drill’s working state is introduced. Multi sensor data fusion is done with the aid of BP neural network in Matlab. The data to be interfused are pre processed and the program of simulation and “point checking” is given.
文摘We describe and experimentally demonstrate a measuring technique for Mach–Zehnder interferometer(MZI)based integrated photonic biochemical sensors. Our technique is based on the direct measurement of phase changes between the arms of the MZI, achieved by signal modulation on one of the arms of the interferometer together with pseudoheterodyne detection, and it allows us to avoid the use of costly equipment such as tunable light sources or spectrum analyzers. The obtained output signal is intrinsically independent of wavelength, power variations, and global thermal variations, making it extremely robust and adequate for use in real conditions. Using a silicon-on-insulator MZI, we demonstrate the real-time monitoring of refractive index variations and achieve a detection limit of 4.1 × 10^(-6)refractive index units(RIU).
基金funding from the European Union’s Seventh Framework Programme managed by REA Research Executive Agency http://ec.europa.eu/rea (FP7/2007-2013) under grant agreement no.314018 FP7-SME-2012-SMEsupport of this study by the Kompetenznetz Funktionelle Nanostrukturen Baden Wuerttemberg,Germany
文摘Optical simulations of GaAs/AlGaAs thin-film waveguides were performed for investigating the dependence of the modal behavior on waveguide geometry and the resulting analytical sensitivity. Simulations were performed for two distinct mid-infrared wavelengths, thereby demonstrating the necessity of individually designed waveguide structures for each spectral regime of interest. Hence, the modal behavior, sensitivity, and intensity of the evanescent field were investigated via modeling studies at 1600 and 1000 cm^(-1), thereby confirming the utility of such simulations for designing mid-infrared sensors based on thin-film waveguide technology.
基金supported by the National Natural Science Foundation of China(No.61922032)We thank the Program for the Academic Frontier Youth Team of Huazhong University of Science and Technology(HUST)(No.2018QYTD06)the Innovation Fund of Wuhan National Laboratory for Optoelectronics.
文摘Integrated sensor combines multiple sensor functions into a single unit,which has the advantages of miniaturization and better application potential.However,limited by the sensing platforms of the sensor and the selectivity of the sensitive film,there are still challenges to realize multi-component gas detection in one unit.Herein,a principle integration method is proposed to achieve the multi-component gas detection based on the acoustics-electricity-mechanics coupling effect.The electrical and mechanical properties of the Bi_(2)S_(3)nanobelts materials in different atmospheres indicate the possibility of realizing the principle integration.At the same time,the surface acoustic wave(SAW)sensor as a multivariable physical transducer can sense both electrical and mechanical properties.Upon exposure to 10 ppm NO_(2),NH_(3),and their mixtures,the integrated SAW gas sensor shows a 4.5 kHz positive frequency shift(acoustoelectric effect),an 11 kHz negative frequency shift(mechanics effects),and a reduced 4 kHz negative frequency shift(acoustics-electricity-mechanics coupling effect),respectively.Moreover,we realize wireless passive detection of NO_(2)and NH_(3)based on the SAW sensor.Our work provides valuable insights that can serve as a guide to the design and fabrication of single sensors offering multi-component gas detection via different gas sensing mechanisms.
基金supported by the National Basic Research Program of China(Grant No.2011CB707605)National Natural Science Foundation of China(Grant Nos.50925519 and 51375092)G.S.Wu was supported by the Scientific Research Foundation of Graduate School of Southeast University
文摘Third generation DNA sequencing relies on monitoring the ionic current blockage during the DNA molecule’s threading through a nanoscale pore.It is still really tough to attain the single base discrimination on a DNA strand by merely analyzing the ionic current due to speedy DNA translocation and low spatial resolution.More integrated configurations are pursued to present versatile comparative dissimilarities of the four bases by enhancing the spatial resolution within a DNA molecule translocation event,such as transverse tunneling current,local potential change,and capacitance oriented voltage resonance.In this mini review,the insight is provided into the status quo on several functionalized techniques and methodologies for DNA sequencing and furthermore concluding remark and outlook are presented.
基金This study is supported by the Natural Science Foundation of China (Grant No. 51274150) and Shanxi Province Natural Science Foundation of China (Grant No. 201601 D011059).
文摘Infrared and visible light image fusion technology is a hot spot in the research of multi-sensor fusion technology in recent years. Existing infrared and visible light fusion technologies need to register before fusion because of using two cameras. However, the application effect of the registration technology has yet to be improved. Hence, a novel integrative multi-spectral sensor device is proposed for infrared and visible light fusion, and by using the beam splitter prism, the coaxial light incident from the same lens is projected to the infrared charge coupled device (CCD) and visible light CCD, respectively. In this paper, the imaging mechanism of the proposed sensor device is studied with the process of the signals acquisition and fusion. The simulation experiment, which involves the entire process of the optic system, signal acquisition, and signal fusion, is constructed based on imaging effect model. Additionally, the quality evaluation index is adopted to analyze the simulation result. The experimental results demonstrate that the proposed sensor device is effective and feasible.
基金Project supported by the National Natural Science Foundation of China(No.90607003).
文摘A newΣΔmodulator architecture for thermal vacuum sensor ASICs is proposed.The micro-hotplate thermal vacuum sensor fabricated by surface-micrornachining technology can detect the gas pressure from 1 to 10;Pa. The amplified differential output voltage signal of the sensor feeds to theΣΔmodulator to be converted into digital domain.The presentedΣΔmodulator makes use of a feed-forward path to suppress the harmonic distortions and attain high linearity.Compared with other feed-forward architectures presented before,the circuit complexity,chip area and power dissipation of the proposed architecture are significantly decreased.The correlated double sampling technique is introduced in the 1st integrator to reduce the flicker noise.The measurement results demonstrate that the modulator achieves an SNDR of 79.7 dB and a DR of 80 dB over a bandwidth of 7.8 kHz at a sampling rate of 4 MHz.The circuit has been fabricated in a 0.5μm 2P3M standard CMOS technology.It occupies an area of 5 mm;and dissipates 9 mW from a single 3 V power supply.The performance of the modulator meets the requirements of the considered application.
基金supported by the Natural Science Foundation of Jiangsu Province(Nos.BK20140246 and BK20160417)the National Natural Science Foundation of China(No.61371057,61601251,11404092,and61701261)+1 种基金the China Postdoctoral Science Foundation Funded Project(No.2016M601586)the Fundamental Research Funds for the Central Universities(No.2017B14914)
文摘We report experimental realization of Raman spectra enhancement of copper phthalocyanine, using an on-chip metallic planar waveguide of the sub-millimeter scale. The oscillating ultrahigh order modes excited by the direct coupling method yield high optical intensity at resonance, which is different from the conventional strategy to create localized "hot spots." The observed excitation efficiency of the Raman signal is significantly enhanced,owing to the high Q factor of the resonant cavity. Furthermore, effective modulation of the Raman intensity is available by adjusting the polymethyl methacrylate(PMMA) thickness in the guiding layer, i.e., by tuning the light–matter interaction length. A large modulation depth is verified through the fact that 10 times variation in the enhancement factor is observed in the experiment as the PMMA thickness varies from 7 to 23 μm.
基金This work was supported by the National Key Research and Development Plan from the Ministry of Science and Technology of China through Grant No. 2016YFC0700500, as well as funding from Innovative Research Groups of the National Natural Science Foundation of China (No. 51521005), and the National Natural Science Foundation of China (No. 51678328 & 21221004 & 41227805 & 21190054).
文摘Indoor airborne bioaerosols of outdoor origin play an important role in determining the exposure of humans to bioaerosols because people spend most of their time indoors. However, there are few studies focusing on indoor bioaerosols originating from outdoors. In this study, indoor versus outdoor size-resolved concentrations and particle asymmetry factors of airborne fluorescent bioaerosols in an office room were measured continuously for 6 days (144 h) using a fluorescent bioaerosol detector. The windows and door of this room were closed to ensure that there was only air infiltration; moreover, any human activities were ceased during sampling to inhibit effects of indoor sources. We focused on fine particles, since few coarse particles enter indoor environments, when windows and doors are closed. Both indoor and outdoor fluorescent bioaerosol size distributions were fit with two-mode lognormal distributions (indoor R2 = 0.935, outdoor R2 = 0.938). Asymmetry factor distributions were also fit with lognormal distributions (indoor R2 = 0.992, outdoor R2 = 0.992). Correlations between indoor and outdoor fluorescent bioaerosol concentrations show significant concentration-attenuation and a time lag during the study period. A two-parameter, semi-empirical model was used to predict concentrations of indoor fluorescent bioaerosols of outdoor origin. The measured and predicted concentrations had a linear relationship for the studied size fractions, with an R2 for all size fractions of larger than 0.83.
基金supported by National Natural Science Foundation of China(Nos.61304131 and 61402147)Grant of China Scholarship Council(No.201608130174)+2 种基金Natural Science Foundation of Hebei Province(Nos.F2016402054 and F2014402075)the Scientific Research Plan Projects of Hebei Education Department(Nos.BJ2014019,ZD2015087 and QN2015046)the Research Program of Talent Cultivation Project in Hebei Province(No.A2016002023)
文摘A heterogeneous wireless sensor network comprises a number of inexpensive energy constrained wireless sensor nodes which collect data from the sensing environment and transmit them toward the improved cluster head in a coordinated way. Employing clustering techniques in such networks can achieve balanced energy consumption of member nodes and prolong the network lifetimes.In classical clustering techniques, clustering and in-cluster data routes are usually separated into independent operations. Although separate considerations of these two issues simplify the system design, it is often the non-optimal lifetime expectancy for wireless sensor networks. This paper proposes an integral framework that integrates these two correlated items in an interactive entirety. For that,we develop the clustering problems using nonlinear programming. Evolution process of clustering is provided in simulations. Results show that our joint-design proposal reaches the near optimal match between member nodes and cluster heads.
基金supported by the National"863"Program of China under Grant No.2008AA01Z130
文摘A digital still camera image processing system on a chip, different from the video camera system, is pre- sented for mobile phone to reduce the power consumption and size. A new color interpolation algorithm is proposed to enhance the image quality. The system can also process fixed patten noise (FPN) reduction, color correction, gamma correction, RGB/YUV space transfer, etc. The chip is controlled by sensor regis- ters by inter-integrated circuit (I2C) interface. The voltage for both the front-end analog and the pad cir- cuits is 2.8 V, and the volatge for the image signal processing is 1.8 V. The chip running under the external 13.5-MHz clock has a video data rate of 30 frames/s and the measured power dissipation is about 75 roW.