The Experts below are selected from a list of 23268 Experts worldwide ranked by ideXlab platform
Chi Chiu Chan - One of the best experts on this subject based on the ideXlab platform.
-
carbon nanotube Polyvinyl Alcohol coated thin core fiber sensor for humidity measurement
Sensors and Actuators B-chemical, 2018Co-Authors: Kai Ni, Xinyong Dong, Yan Ru Wang, Meng Hui Zhou, Chi Chiu ChanAbstract:Abstract A Carbon-nanotube (CNT)/Polyvinyl Alcohol (PVA) composite film-coated thin core fiber (TCF) optics sensor is proposed for monitoring relative humidity (RH). The unique Michelson type fiber interferometer sensor consists a short segment of TCF, the tip of which is melted into a convex shape and coated with a hydroscopic CNT/PVA film. The proposed sensor is linearly responsive to relative humidity (RH) beyond the humidity range 70%RH, with maximum sensitivity of −0.4573 dB/%RH. The advantages of this sensor are its compact size, excellent stability and facile fabrication process.
-
Polyvinyl Alcohol coated photonic crystal optical fiber sensor for humidity measurement
Sensors and Actuators B-chemical, 2012Co-Authors: Wei Chang Wong, Chi Chiu Chan, Li Han Chen, Tao Li, Kam Chew LeongAbstract:Abstract A Polyvinyl Alcohol (PVA) coated photonic crystal optical fiber (PCF) sensor has been proposed as a relative humidity (RH) sensor. It was fabricated by collapsing the holes of PCF at both ends to form a Michelson interferometer with cladding mode excitation. PVA was dip coated onto the sensor and the interference shift was measured when the sensor was exposed to varying RH. The sensor with 9% (w/w) coating showed a high sensitivity of 0.60 nm/%RH, displayed little hysteresis, high repeatability, low cross-sensitivity to temperature and ammonia gas and stability over 7 days of testing. A rise/fall time of 300/500 ms was achieved respectively.
-
Polyvinyl Alcohol coated hybrid fiber grating for relative humidity sensing
Journal of Biomedical Optics, 2011Co-Authors: Chunliu Zhao, Xinyong Dong, Tao Li, Yi Li, Chi Chiu ChanAbstract:A relative humidity (RH) sensor based on a hybrid fiber grating coated with Polyvinyl Alcohol is proposed and demonstrated experimentally. The hybrid fiber grating is formed by superimposing a normal fiber Bragg grating (FBG) and a tilted-FBG around the same position of a single-mode fiber so that it can work in the reflection mode. Optical power of the reflected signal changes with the refractive index of the moisture sensitive Polyvinyl Alcohol, and humidity measurement can be realized. Experimental results show that the measurement range is 30 to 95% with the maximum sensitivity of 0.737 nW/% RH. The average response time is ∼2 s and the measurement is nearly insensitive to temperature. Compared with the wavelength detection method used in normal FBG-based relative humidity sensors, the intensity demodulation method in this report is simpler and more cost-efficient.
-
Polyvinyl Alcohol coated hybrid fiber grating for relative humidity sensing
Journal of Biomedical Optics, 2011Co-Authors: Chunliu Zhao, Xinyong Dong, Yang Liu, Chi Chiu ChanAbstract:A relative humidity (RH) sensor based on a hybrid fiber grating coated with Polyvinyl Alcohol is proposed and demonstrated experimentally. The hybrid fiber grating is formed by superimposing a normal fiber Bragg grating (FBG) and a tilted-FBG around the same position of a single-mode fiber so that it can work in the reflection mode. Optical power of the reflected signal changes with the refractive index of the moisture sensitive Polyvinyl Alcohol, and humidity measurement can be realized. Experimental results show that the measurement range is 30 to 95% with the maximum sensitivity of 0.737 nW/% RH. The average response time is ∼2 s and the measurement is nearly insensitive to temperature. Compared with the wavelength detection method used in normal FBG-based relative humidity sensors, the intensity demodulation method in this report is simpler and more cost-efficient.
Xinyong Dong - One of the best experts on this subject based on the ideXlab platform.
-
carbon nanotube Polyvinyl Alcohol coated thin core fiber sensor for humidity measurement
Sensors and Actuators B-chemical, 2018Co-Authors: Kai Ni, Xinyong Dong, Yan Ru Wang, Meng Hui Zhou, Chi Chiu ChanAbstract:Abstract A Carbon-nanotube (CNT)/Polyvinyl Alcohol (PVA) composite film-coated thin core fiber (TCF) optics sensor is proposed for monitoring relative humidity (RH). The unique Michelson type fiber interferometer sensor consists a short segment of TCF, the tip of which is melted into a convex shape and coated with a hydroscopic CNT/PVA film. The proposed sensor is linearly responsive to relative humidity (RH) beyond the humidity range 70%RH, with maximum sensitivity of −0.4573 dB/%RH. The advantages of this sensor are its compact size, excellent stability and facile fabrication process.
-
Polyvinyl Alcohol coated hybrid fiber grating for relative humidity sensing
Journal of Biomedical Optics, 2011Co-Authors: Chunliu Zhao, Xinyong Dong, Tao Li, Yi Li, Chi Chiu ChanAbstract:A relative humidity (RH) sensor based on a hybrid fiber grating coated with Polyvinyl Alcohol is proposed and demonstrated experimentally. The hybrid fiber grating is formed by superimposing a normal fiber Bragg grating (FBG) and a tilted-FBG around the same position of a single-mode fiber so that it can work in the reflection mode. Optical power of the reflected signal changes with the refractive index of the moisture sensitive Polyvinyl Alcohol, and humidity measurement can be realized. Experimental results show that the measurement range is 30 to 95% with the maximum sensitivity of 0.737 nW/% RH. The average response time is ∼2 s and the measurement is nearly insensitive to temperature. Compared with the wavelength detection method used in normal FBG-based relative humidity sensors, the intensity demodulation method in this report is simpler and more cost-efficient.
-
Polyvinyl Alcohol coated hybrid fiber grating for relative humidity sensing
Journal of Biomedical Optics, 2011Co-Authors: Chunliu Zhao, Xinyong Dong, Yang Liu, Chi Chiu ChanAbstract:A relative humidity (RH) sensor based on a hybrid fiber grating coated with Polyvinyl Alcohol is proposed and demonstrated experimentally. The hybrid fiber grating is formed by superimposing a normal fiber Bragg grating (FBG) and a tilted-FBG around the same position of a single-mode fiber so that it can work in the reflection mode. Optical power of the reflected signal changes with the refractive index of the moisture sensitive Polyvinyl Alcohol, and humidity measurement can be realized. Experimental results show that the measurement range is 30 to 95% with the maximum sensitivity of 0.737 nW/% RH. The average response time is ∼2 s and the measurement is nearly insensitive to temperature. Compared with the wavelength detection method used in normal FBG-based relative humidity sensors, the intensity demodulation method in this report is simpler and more cost-efficient.
Chunliu Zhao - One of the best experts on this subject based on the ideXlab platform.
-
Polyvinyl Alcohol coated hybrid fiber grating for relative humidity sensing
Journal of Biomedical Optics, 2011Co-Authors: Chunliu Zhao, Xinyong Dong, Tao Li, Yi Li, Chi Chiu ChanAbstract:A relative humidity (RH) sensor based on a hybrid fiber grating coated with Polyvinyl Alcohol is proposed and demonstrated experimentally. The hybrid fiber grating is formed by superimposing a normal fiber Bragg grating (FBG) and a tilted-FBG around the same position of a single-mode fiber so that it can work in the reflection mode. Optical power of the reflected signal changes with the refractive index of the moisture sensitive Polyvinyl Alcohol, and humidity measurement can be realized. Experimental results show that the measurement range is 30 to 95% with the maximum sensitivity of 0.737 nW/% RH. The average response time is ∼2 s and the measurement is nearly insensitive to temperature. Compared with the wavelength detection method used in normal FBG-based relative humidity sensors, the intensity demodulation method in this report is simpler and more cost-efficient.
-
Polyvinyl Alcohol coated hybrid fiber grating for relative humidity sensing
Journal of Biomedical Optics, 2011Co-Authors: Chunliu Zhao, Xinyong Dong, Yang Liu, Chi Chiu ChanAbstract:A relative humidity (RH) sensor based on a hybrid fiber grating coated with Polyvinyl Alcohol is proposed and demonstrated experimentally. The hybrid fiber grating is formed by superimposing a normal fiber Bragg grating (FBG) and a tilted-FBG around the same position of a single-mode fiber so that it can work in the reflection mode. Optical power of the reflected signal changes with the refractive index of the moisture sensitive Polyvinyl Alcohol, and humidity measurement can be realized. Experimental results show that the measurement range is 30 to 95% with the maximum sensitivity of 0.737 nW/% RH. The average response time is ∼2 s and the measurement is nearly insensitive to temperature. Compared with the wavelength detection method used in normal FBG-based relative humidity sensors, the intensity demodulation method in this report is simpler and more cost-efficient.
I. Kelman Cohen - One of the best experts on this subject based on the ideXlab platform.
-
The wound healing process in surgical patients evaluated by the expanded polytetrafluoroethylene and the Polyvinyl Alcohol sponge: a comparison with special reference to intrapatient variability.
Wound Repair and Regeneration, 1995Co-Authors: Lars N. Jorgensen, Finn Kallehave, Tonny Karlsmark, Robert F. Diegelmann, I. Kelman Cohen, Lars Olsen, Finn GottrupAbstract:The aim of this study was to compare two wound healing models in surgical patients with special reference to the intrapatient variability. Two pieces of expanded polytetrafluoroethylene tubing and one perforated silicone tube containing two Polyvinyl Alcohol sponges were subcutaneously inserted into 28 patients and were removed after 10 (9 to 11) days. The amount of hydroxy-l-proline in two segments of the same piece of expanded polytetrafluoroethylene tubing correlated significantly with each other. Similar results were found for proline. Proline content in each Polyvinyl Alcohol sponge correlated weakly with each other, whereas no correlation was found between hydroxy-l-proline content in the two Polyvinyl Alcohol sponges from the same patient. In addition, no correlation was found between leucine in the two adjacent Polyvinyl Alcohol sponges or between the hydroxy-l-proline/leucine ratio in these same sponges. No concordance could be detected between the averages of hydroxy-l-proline content in the two segments of expanded polytetrafluoroethylene tubing and the hydroxy-l-proline content in the two Polyvinyl Alcohol sponges from the same person, although an association between the averages of proline in the two pieces of expanded polytetrafluoroethylene tubing and proline content in the two Polyvinyl Alcohol sponges from the same individual was observed. The measurement error was greater for the Polyvinyl Alcohol sponges than for the expanded polytetrafluoroethylene tubing implants during the first 10 days after wounding. The expanded polytetrafluoroethylene tubing accumulated 2.5 times more hydroxy-l-proline per length unit than the Polyvinyl Alcohol sponge. We concluded that the expanded polytetrafluoroethylene implant rather than the Polyvinyl Alcohol implant is preferred for quantitation of subcutaneous collagen deposition in surgical patients because it accumulates more new tissue and has a lower variability.
-
Comparison of the Polyvinyl Alcohol sponge and expanded polytetrafluoroethylene subcutaneous implants as models to evaluate wound healing potential in human beings.
Wound Repair and Regeneration, 1995Co-Authors: Samuel M. Alaish, David A. Bettinger, Oluyinka O. Olutoye, Lisa J. Gould, Dorne R. Yager, Anthony Davis, Mary C. Crossland, Robert F. Diegelmann, I. Kelman CohenAbstract:Our current understanding of the complex processes involved in wound healing is based mainly on studies of animal models. Although this information has been useful, it may not totally reflect the response found in human beings. For example, human beings have a tendency to either "overheal," as seen in keloids and hypertrophic scar formation, or have deficient healing, as seen in chronic ulcer formation. No animal models are available to analyze these human clinical pathologic conditions. Therefore the objective of this study was to analyze the wound healing response in a large population (n = 40) of normal healthy human beings as a first step to begin studies of abnormal human wound healing. Simultaneously, a comparison was made between the Polyvinyl Alcohol implant and the expanded polytetrafluoroethylene implant model. Under sterile conditions with the use of local anesthesia, two preweighed Polyvinyl Alcohol implants and two standard 6 cm expanded polytetrafluoroethylene implants were placed subcutaneously in the upper arm of each subject. High-performance liquid chromatography was used to quantitate isoleucine and hydroxy-l-proline in acid hydrolysates of each implant. Isoleucine was used as an indicator of protein content in the tissue sample, whereas hydroxyproline reflected collagen content. No infectious or hemorrhagic complications were found in the 40 volunteers included in the study. No significant difference was found in isoleucine or hydroxy-l-proline content between postoperative day 7 Polyvinyl Alcohol implants and day 14 Polyvinyl Alcohol implants. In contrast, both isoleucine and hydroxy-l-proline content were significantly increased in day 14 expanded polytetrafluoroethylene implants compared with day 7 implants (p < 0.005 and p < 0.001, respectively). In addition, the ratio of hydroxy-l-proline to isoleucine was significantly increased in day 14 expanded polytetrafluoroethylene implants compared with day 7 expanded polytetrafluoroethylene and both day 7 and day 14 Polyvinyl Alcohol implants (p < 0.001). This observation suggests that by 14 days implantation of expanded polytetrafluoroethylene stimulated an increased deposition of collagen. No significant differences were found in the hydroxy-l-proline to isoleucine ratios among day 7 expanded polytetrafluoroethylene, day 7 Polyvinyl Alcohol, and day 14 Polyvinyl Alcohol implants. Histologic analyses correlated with the biochemical findings. These results suggest that expanded polytetrafluoroethylene may be the preferred implant for studies designed to examine pathologic processes associated with retarded wound healing. In contrast, the Polyvinyl Alcohol implant may be better suited for studies where a low background response is required. Moreover, the extreme variability in normal healthy volunteers seen in this study correlates clinically with the finding that, among the normal adult human population, there is a heterogeneous wound healing response.
Robert F. Diegelmann - One of the best experts on this subject based on the ideXlab platform.
-
The wound healing process in surgical patients evaluated by the expanded polytetrafluoroethylene and the Polyvinyl Alcohol sponge: a comparison with special reference to intrapatient variability.
Wound Repair and Regeneration, 1995Co-Authors: Lars N. Jorgensen, Finn Kallehave, Tonny Karlsmark, Robert F. Diegelmann, I. Kelman Cohen, Lars Olsen, Finn GottrupAbstract:The aim of this study was to compare two wound healing models in surgical patients with special reference to the intrapatient variability. Two pieces of expanded polytetrafluoroethylene tubing and one perforated silicone tube containing two Polyvinyl Alcohol sponges were subcutaneously inserted into 28 patients and were removed after 10 (9 to 11) days. The amount of hydroxy-l-proline in two segments of the same piece of expanded polytetrafluoroethylene tubing correlated significantly with each other. Similar results were found for proline. Proline content in each Polyvinyl Alcohol sponge correlated weakly with each other, whereas no correlation was found between hydroxy-l-proline content in the two Polyvinyl Alcohol sponges from the same patient. In addition, no correlation was found between leucine in the two adjacent Polyvinyl Alcohol sponges or between the hydroxy-l-proline/leucine ratio in these same sponges. No concordance could be detected between the averages of hydroxy-l-proline content in the two segments of expanded polytetrafluoroethylene tubing and the hydroxy-l-proline content in the two Polyvinyl Alcohol sponges from the same person, although an association between the averages of proline in the two pieces of expanded polytetrafluoroethylene tubing and proline content in the two Polyvinyl Alcohol sponges from the same individual was observed. The measurement error was greater for the Polyvinyl Alcohol sponges than for the expanded polytetrafluoroethylene tubing implants during the first 10 days after wounding. The expanded polytetrafluoroethylene tubing accumulated 2.5 times more hydroxy-l-proline per length unit than the Polyvinyl Alcohol sponge. We concluded that the expanded polytetrafluoroethylene implant rather than the Polyvinyl Alcohol implant is preferred for quantitation of subcutaneous collagen deposition in surgical patients because it accumulates more new tissue and has a lower variability.
-
Comparison of the Polyvinyl Alcohol sponge and expanded polytetrafluoroethylene subcutaneous implants as models to evaluate wound healing potential in human beings.
Wound Repair and Regeneration, 1995Co-Authors: Samuel M. Alaish, David A. Bettinger, Oluyinka O. Olutoye, Lisa J. Gould, Dorne R. Yager, Anthony Davis, Mary C. Crossland, Robert F. Diegelmann, I. Kelman CohenAbstract:Our current understanding of the complex processes involved in wound healing is based mainly on studies of animal models. Although this information has been useful, it may not totally reflect the response found in human beings. For example, human beings have a tendency to either "overheal," as seen in keloids and hypertrophic scar formation, or have deficient healing, as seen in chronic ulcer formation. No animal models are available to analyze these human clinical pathologic conditions. Therefore the objective of this study was to analyze the wound healing response in a large population (n = 40) of normal healthy human beings as a first step to begin studies of abnormal human wound healing. Simultaneously, a comparison was made between the Polyvinyl Alcohol implant and the expanded polytetrafluoroethylene implant model. Under sterile conditions with the use of local anesthesia, two preweighed Polyvinyl Alcohol implants and two standard 6 cm expanded polytetrafluoroethylene implants were placed subcutaneously in the upper arm of each subject. High-performance liquid chromatography was used to quantitate isoleucine and hydroxy-l-proline in acid hydrolysates of each implant. Isoleucine was used as an indicator of protein content in the tissue sample, whereas hydroxyproline reflected collagen content. No infectious or hemorrhagic complications were found in the 40 volunteers included in the study. No significant difference was found in isoleucine or hydroxy-l-proline content between postoperative day 7 Polyvinyl Alcohol implants and day 14 Polyvinyl Alcohol implants. In contrast, both isoleucine and hydroxy-l-proline content were significantly increased in day 14 expanded polytetrafluoroethylene implants compared with day 7 implants (p < 0.005 and p < 0.001, respectively). In addition, the ratio of hydroxy-l-proline to isoleucine was significantly increased in day 14 expanded polytetrafluoroethylene implants compared with day 7 expanded polytetrafluoroethylene and both day 7 and day 14 Polyvinyl Alcohol implants (p < 0.001). This observation suggests that by 14 days implantation of expanded polytetrafluoroethylene stimulated an increased deposition of collagen. No significant differences were found in the hydroxy-l-proline to isoleucine ratios among day 7 expanded polytetrafluoroethylene, day 7 Polyvinyl Alcohol, and day 14 Polyvinyl Alcohol implants. Histologic analyses correlated with the biochemical findings. These results suggest that expanded polytetrafluoroethylene may be the preferred implant for studies designed to examine pathologic processes associated with retarded wound healing. In contrast, the Polyvinyl Alcohol implant may be better suited for studies where a low background response is required. Moreover, the extreme variability in normal healthy volunteers seen in this study correlates clinically with the finding that, among the normal adult human population, there is a heterogeneous wound healing response.
