Sub-micron color sensors are developed, using carbon nanotubes (CNTs). The color sensor consists of an array of two photodiodes with different spectral responses, fabricated using controlled electric peeling-off and...Sub-micron color sensors are developed, using carbon nanotubes (CNTs). The color sensor consists of an array of two photodiodes with different spectral responses, fabricated using controlled electric peeling-off and doping-free techniques on a single semiconducting double-wall CNT. The CNT photodiodes exhibit intrinsic broad spectral responses from 640 to 2,100 nm, large linear dynamic ranges of over 60 dB, and sub-micron pixel size. This method explores the unique properties of multi-wall CNTs, and may be readily used for large-scale fabrication of high performance color sensor arrays, when arrays of parallel multi-wall CNTs become available.展开更多
Changes of the average brightness and non-uniformity of dark output images,and quality of pictures captured under natural lighting for the color CMOS digital image sensorsirradiated at different electron doses have be...Changes of the average brightness and non-uniformity of dark output images,and quality of pictures captured under natural lighting for the color CMOS digital image sensorsirradiated at different electron doses have been studied in comparison to those from theγ-irradiated sensors. For the electron-irradiated sensors, the non-uniformity increases obviouslyand a small bright region on the dark image appears at the dose of 0.4 kGy. The average brightnessincreases at 0.4 kGy, increases sharply at 0.5 kGy. The picture is very blurry only at 0.6 kGy,showing the sensor undergoes severe performance degradation. Electron radiation damage is much moresevere than γ radiation damage for the CMOS image sensors. A possible explanation is presented inthis paper.展开更多
We investigated the steady state gamma-ray radiation response of pure-silica-core photonic crystal fibers(PSC-PCFs)under an accumulated dose of 500 Gy and a dose rate of 2.38 Gy/min. The radiation-induced attenuatio...We investigated the steady state gamma-ray radiation response of pure-silica-core photonic crystal fibers(PSC-PCFs)under an accumulated dose of 500 Gy and a dose rate of 2.38 Gy/min. The radiation-induced attenuation(RIA) spectra in the near-infrared region from 800 nm to 1700 nm were obtained. We find that the RIA at 1550 nm is related with hydroxyl(OH^-) absorption defects in addition to the identified self-trapped hole(STH) defects. Moreover, it is proposed and demonstrated that reduced OH^-absorption defects can decrease the RIA at 1550 nm. The RIA at 1550 nm has effectively declined from 27.7 d B/km to 3.0 dB/km through fabrication improvement. Preliminary explanations based on the unique fabrication processes were given to interpret the RIA characteristics of PSC-PCFs. The results show that the PSC-PCFs,which offer great advantages over conventional fibers, are promising and applicable to fiber sensors in harsh environments.展开更多
An animal's pelage,feather,or skin color can serve a variety of functions,so it is important to have multiple standardized methods for measuring color.One of the most common and reliable methods for measuring anim...An animal's pelage,feather,or skin color can serve a variety of functions,so it is important to have multiple standardized methods for measuring color.One of the most common and reliable methods for measuring animal coloration is the use of standardized digital photographs of animals.New tech no logy in the form of a commercially available handheld digital color sensor could provide an alter native to photography-based animal color measurements.To determine whether a digital color sensor could be used to measure animal coloration,we tested the ability of a digital color sensor to measure coloration of mammalian,avian,and lepidopteran museums specimens.We compared results from the sensor to measurements taken using traditional photography methods.Our study yielded significant differences between photography-based and digital color sensor measurements of brightness(light to dark)and colors along the green to red spectrum.There was no difference between photographs and the digital color sensor measurements for colors along the blue to yellow spectrum.The average difference in recorded color(AE)by the 2 methods was above the threshold at which humans can perceive a difference.There were sign讦icant correlations between the sensor and photographs for all measurements indicating that the sensor is an effective animal coloration measuring tool.However,the sensor's small aperture and narrow light spectrum range designed for human-vision limit its value for ecological research.We discuss the conditions in which a digital color sensor can be an effective tool for measuring animal coloration in both laboratory settings and in the field.展开更多
Working principles of silicon double P-N junction color sensor are introduced and a color measurement system to distinguish tooth color difference is designed in this paper.This system consists of silicon double P-N j...Working principles of silicon double P-N junction color sensor are introduced and a color measurement system to distinguish tooth color difference is designed in this paper.This system consists of silicon double P-N junction,a small optical fiber probe,signal process circuit and an MSP430FG439 single-chip system.Small in size,this system can measure different parts of the tooth in a fast and convenient way with high-accuracy.Thus,this system will be very promising in building prosthodontics and tooth fabrication.展开更多
This paper investigates the selective liquid response for Morpho didius butterfly wing scales and propose an optical model to explain the effect of different components on the liquid response. It is found out that the...This paper investigates the selective liquid response for Morpho didius butterfly wing scales and propose an optical model to explain the effect of different components on the liquid response. It is found out that the reason of the selective response is that the liquid media forms nanometre-thick films between ridge-lamellae nanostructures and changes the constructive interference wavelength. There is linear relation between the structural color of ridge-lamellae structure and index of liquid background media. The reason of vapor's responses is that the nanometre-thick liquid fi lms on ridge-lamellae nanostructures change the constructive interference wavelength. These liquid films are formed due to vapor adsorption. Therefore,the selective linear liquid response can be applied to design nano-engineered photonic liquid and vapor sensors.展开更多
In clinical practice,examination of the hemorrhagic spot (HS) remains difficult.In this paper,we describe a remote controlled capsule (RCC) micro-system with an automated,color-based sensor to identify and localize th...In clinical practice,examination of the hemorrhagic spot (HS) remains difficult.In this paper,we describe a remote controlled capsule (RCC) micro-system with an automated,color-based sensor to identify and localize the HS of the gastrointestinal (GI) tract.In vitro testing of the detecting sensor demonstrated that it was capable of discriminating mimetic intestinal fluid (MIF) with and without the hemoglobin (Hb) when the concentration of Hb in MIF was above 0.05 g/ml.Therefore,this RCC system is able to detect the relatively accurate location of the HS in the GI tract.展开更多
基金Acknowledgements This work was supported by the National Natural Science Foundation of China (Nos. 61321001, 61427901-002, 61390504 and 61271051), and Beijing Municipal Science and Technology Commission (No. Z151100003315009).
文摘Sub-micron color sensors are developed, using carbon nanotubes (CNTs). The color sensor consists of an array of two photodiodes with different spectral responses, fabricated using controlled electric peeling-off and doping-free techniques on a single semiconducting double-wall CNT. The CNT photodiodes exhibit intrinsic broad spectral responses from 640 to 2,100 nm, large linear dynamic ranges of over 60 dB, and sub-micron pixel size. This method explores the unique properties of multi-wall CNTs, and may be readily used for large-scale fabrication of high performance color sensor arrays, when arrays of parallel multi-wall CNTs become available.
基金This project is financially supported by the Narional Natural Science Foundation of China(Nos 10375034 and 10075029) and the Basic Research Foundation of Tsinghua University (No. JC2002058).
文摘Changes of the average brightness and non-uniformity of dark output images,and quality of pictures captured under natural lighting for the color CMOS digital image sensorsirradiated at different electron doses have been studied in comparison to those from theγ-irradiated sensors. For the electron-irradiated sensors, the non-uniformity increases obviouslyand a small bright region on the dark image appears at the dose of 0.4 kGy. The average brightnessincreases at 0.4 kGy, increases sharply at 0.5 kGy. The picture is very blurry only at 0.6 kGy,showing the sensor undergoes severe performance degradation. Electron radiation damage is much moresevere than γ radiation damage for the CMOS image sensors. A possible explanation is presented inthis paper.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61575012 and 61575013)the National Key Scientific Instrument and Equipment Development Project,China(Grant No.2013YQ040877)
文摘We investigated the steady state gamma-ray radiation response of pure-silica-core photonic crystal fibers(PSC-PCFs)under an accumulated dose of 500 Gy and a dose rate of 2.38 Gy/min. The radiation-induced attenuation(RIA) spectra in the near-infrared region from 800 nm to 1700 nm were obtained. We find that the RIA at 1550 nm is related with hydroxyl(OH^-) absorption defects in addition to the identified self-trapped hole(STH) defects. Moreover, it is proposed and demonstrated that reduced OH^-absorption defects can decrease the RIA at 1550 nm. The RIA at 1550 nm has effectively declined from 27.7 d B/km to 3.0 dB/km through fabrication improvement. Preliminary explanations based on the unique fabrication processes were given to interpret the RIA characteristics of PSC-PCFs. The results show that the PSC-PCFs,which offer great advantages over conventional fibers, are promising and applicable to fiber sensors in harsh environments.
基金Funding for this study was provided by Florida's State Wildlife Grant through Florida's Wildlife Legacy Initiative.
文摘An animal's pelage,feather,or skin color can serve a variety of functions,so it is important to have multiple standardized methods for measuring color.One of the most common and reliable methods for measuring animal coloration is the use of standardized digital photographs of animals.New tech no logy in the form of a commercially available handheld digital color sensor could provide an alter native to photography-based animal color measurements.To determine whether a digital color sensor could be used to measure animal coloration,we tested the ability of a digital color sensor to measure coloration of mammalian,avian,and lepidopteran museums specimens.We compared results from the sensor to measurements taken using traditional photography methods.Our study yielded significant differences between photography-based and digital color sensor measurements of brightness(light to dark)and colors along the green to red spectrum.There was no difference between photographs and the digital color sensor measurements for colors along the blue to yellow spectrum.The average difference in recorded color(AE)by the 2 methods was above the threshold at which humans can perceive a difference.There were sign讦icant correlations between the sensor and photographs for all measurements indicating that the sensor is an effective animal coloration measuring tool.However,the sensor's small aperture and narrow light spectrum range designed for human-vision limit its value for ecological research.We discuss the conditions in which a digital color sensor can be an effective tool for measuring animal coloration in both laboratory settings and in the field.
基金supported by the Innovation Fund for Small Technology-based Firms of China (No.06C26222200838).
文摘Working principles of silicon double P-N junction color sensor are introduced and a color measurement system to distinguish tooth color difference is designed in this paper.This system consists of silicon double P-N junction,a small optical fiber probe,signal process circuit and an MSP430FG439 single-chip system.Small in size,this system can measure different parts of the tooth in a fast and convenient way with high-accuracy.Thus,this system will be very promising in building prosthodontics and tooth fabrication.
基金Supported by the National Natural Science Foundation of China(51305129)the Natural Science Foundation of Hubei Province(Q20151411)
文摘This paper investigates the selective liquid response for Morpho didius butterfly wing scales and propose an optical model to explain the effect of different components on the liquid response. It is found out that the reason of the selective response is that the liquid media forms nanometre-thick films between ridge-lamellae nanostructures and changes the constructive interference wavelength. There is linear relation between the structural color of ridge-lamellae structure and index of liquid background media. The reason of vapor's responses is that the nanometre-thick liquid fi lms on ridge-lamellae nanostructures change the constructive interference wavelength. These liquid films are formed due to vapor adsorption. Therefore,the selective linear liquid response can be applied to design nano-engineered photonic liquid and vapor sensors.
基金Project supported by the National Natural Science Foundation of China (Nos. 30700160 and 30970883)the Postdoctoral Science Foundation of China (Nos. 20070420718 and 200801225)+1 种基金Chongqing University Postgraduates’ Science and Innovation Fund (No. 2008 01A1B0250284)the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20070611045), China
文摘In clinical practice,examination of the hemorrhagic spot (HS) remains difficult.In this paper,we describe a remote controlled capsule (RCC) micro-system with an automated,color-based sensor to identify and localize the HS of the gastrointestinal (GI) tract.In vitro testing of the detecting sensor demonstrated that it was capable of discriminating mimetic intestinal fluid (MIF) with and without the hemoglobin (Hb) when the concentration of Hb in MIF was above 0.05 g/ml.Therefore,this RCC system is able to detect the relatively accurate location of the HS in the GI tract.