Quantum well intermixing techniques modify the geometric shape of quantum wells to allow postgrowth adjustments.The tuning effect on the optical response property of a GaAs/AlGaAs quantum well infrared photodetector(Q...Quantum well intermixing techniques modify the geometric shape of quantum wells to allow postgrowth adjustments.The tuning effect on the optical response property of a GaAs/AlGaAs quantum well infrared photodetector(QWIP) induced by the interdifussion of Al atoms was studied theoretically.By assuming an improvement of the heterointerface quality and an enhanced Al interdiffusion caused by postgrowth intermixings,the photoluminescence spectrum shows a blue-shifted,narrower and enhanced photoluminescence peak.The infrared optical absorption spectrum also shows the expected redshift of the response wavelength.However,the variation in the absorption peak intensity depends on the boundary conditions of the photo generated carriers.For high-quality QWIP samples,the mean free path of photocarriers is long so that the photocarriers are largely coherent when they transport across quantum wells.In this case,the enhanced Al interdiffusion can significantly degrade the infrared absorption property of the QWIP.Special effects are therefore needed to maintain and/or improve the optical properties of the QWIP device during postgrowth treatments.展开更多
The manganite perovskite polycrystal samples of （La1-xDyx）2/3Sr1/3MnO3 （x = 0, 0.1, 0.2, 0.35, and 0.5） doped with Dy were prepared by solid state reaction in atmosphere to measure their X-ray diffraction （XRD） ...The manganite perovskite polycrystal samples of （La1-xDyx）2/3Sr1/3MnO3 （x = 0, 0.1, 0.2, 0.35, and 0.5） doped with Dy were prepared by solid state reaction in atmosphere to measure their X-ray diffraction （XRD） patterns, scanning electric microscope （SEM） images, infrared absorption spectra, and microwave electromagnetic properties. The displacement of the XRD peaks of the samples was found, and the 2θ increases from 0.05o to 0.5o. The grains of undoped La2/3Sr1/3MnO3 not only have the greatest size, but also the most regular shape. The size of the grains decreases as the Dy doping content increases from 0 to 0.5. The infrared absorption spectra of all samples were measured at room temperature. An absorption peak corresponding to the stretching vibration mode of Mn-O bonds appears within the range of 591-629 cm-1. The absorption peak shifts from a higher frequency to a lower one with the decrease of the average ionic radius of A-site. The frequency de- pendence of microwave-absorbing properties, imaginary components of the complex magnetic permeability μ＂ and dielectric permeability ε＂ for all samples was measured at room temperature from 8 to 13 GHz. The results show that the loss of microwave absorption can be attrib- uted to both the magnetic and electric losses. The increase of Dy content not only enhances the microwave absorption but also causes the displacement of the absorption peaks.展开更多
In the infrared spectrum absorbed type gas concentration sensor,voltage signal obtained from the two-channel thermopile infrared detector TPS2534 is very weak.In order to solve this problem,the authors have establishe...In the infrared spectrum absorbed type gas concentration sensor,voltage signal obtained from the two-channel thermopile infrared detector TPS2534 is very weak.In order to solve this problem,the authors have established the structure of the sensor and designed weak signal detecting circuit of the sensor based on infrared spectrum absorption principle,differential de-noising principle and weak signal detecting principle.The authors have made experiments using CH4 gas.The results show that the circuit can remove noise effectively and detect weak electrical signal obtained from the detector.展开更多
Infrared （IR） absorption spectra and X-ray powder diffraction （XRD） patterrns of sexpenfine cat＇s eye from Sichuan Province have been investigated, and infrared absorption bands of the serpentine have been assign...Infrared （IR） absorption spectra and X-ray powder diffraction （XRD） patterrns of sexpenfine cat＇s eye from Sichuan Province have been investigated, and infrared absorption bands of the serpentine have been assigned in this paper. The results indicate that the bands near 3 600 - 3 700 cm^-1 belong to the stretching absorption band VOH, the bands in 948 - 1 100 cm^-1 axe assigned to the stretching vibraling band Usvo, and the bands at 600 570 and 440 cm^-1 respectively belong to the bending vibration band VOH, δMg-O and δSi-O. The serpentine cat＇ s eye includes two types： chrysotile and antigorite. Chrysotile has a sharp and intensive band at 3 688 cm^-1 and a weak band at 3 643 cm^-1 , while antigorite has only one intensive band in the region. At vibration band VSi-O, chrysotile and antigorite have a similar feature at 1 071 cm^-1, but the band at 980 cm^-1 in anfigorite has been split into two bands in chrysotile - a strong one at 1 027 cm^-1 and a weak one at 949 cm^-1. In addition, antigorite has a characteristic bending vibrating band δMg-O at 570 cm^-1. Based on the analysis of the feature of crystal structure, their IR differences axe well explained.展开更多
The infrared(IR)absorption spectral data of 63 kinds of lubricating greases containing six different types of thickeners were obtained using the IR spectroscopy.The Kohonen neural network algorithm was used to identif...The infrared(IR)absorption spectral data of 63 kinds of lubricating greases containing six different types of thickeners were obtained using the IR spectroscopy.The Kohonen neural network algorithm was used to identify the type of the lubricating grease.The results show that this machine learning method can effectively eliminate the interference fringes in the IR spectrum,and complete the feature selection and dimensionality reduction of the high-dimensional spectral data.The 63 kinds of greases exhibit spatial clustering under certain IR spectrum recognition spectral bands,which are linked to characteristic peaks of lubricating greases and improve the recognition accuracy of these greases.The model achieved recognition accuracy of 100.00%,96.08%,94.87%,100.00%,and 87.50%for polyurea grease,calcium sulfonate composite grease,aluminum(Al)-based grease,bentonite grease,and lithium-based grease,respectively.Based on the different IR absorption spectrum bands produced by each kind of lubricating grease,the three-dimensional spatial distribution map of the lubricating grease drawn also verifies the accuracy of classification while recognizing the accuracy.This paper demonstrates fast recognition speed and high accuracy,proving that the Kohonen neural network algorithm has an efficient recognition ability for identifying the types of the lubricating grease.展开更多
AIM： To prepare a complex of hyaluronic acid （HA） and phospholipids （PL）, and study the improvement effect of PL on the oral absorption of HA. METHODS： The complex of HA-PL （named Haplex） was prepared by film ...AIM： To prepare a complex of hyaluronic acid （HA） and phospholipids （PL）, and study the improvement effect of PL on the oral absorption of HA. METHODS： The complex of HA-PL （named Haplex） was prepared by film dispersion and sonication method, its physico-chemical properties were identified by infrared spectra and differential scanning calorimetry （DSC）. The oral absorption of Haplex was studied. Thirty-two healthy rats were divided into 4 groups randomly： （1） a normal saline （NS） control group; （2） an HA group; （3） a mixture group and （4） a Haplex group. After intragastric administration, the concentration of HA in serum was determined. RESULTS： The physico-chemical properties of Haplex were different from HA or PL or their mixture. After Haplex was administered to rats orally, the serum concentration of HA was increased when compared with the mixture or HA control groups from 4 h to 10 h （P 〈 0.05）. The AAUCo-12, of Haplex was also greater than that of the other three groups （P 〈 0.05）. CONCLUSION： The method of film dispersion and sonication can prepare HA and PL complex, and PL can enhance the oral absorption of exogenous HA.展开更多
Infrared emissivity was studied in Zno.99Mo.olO （M is Mn, Fe or Ni） and Znl_xCoxO （x=0.01, 0.02, 0.03 and 0.04） powders synthesized by solid-state reaction at various temperatures. XRD patterns confirm the wurtzit...Infrared emissivity was studied in Zno.99Mo.olO （M is Mn, Fe or Ni） and Znl_xCoxO （x=0.01, 0.02, 0.03 and 0.04） powders synthesized by solid-state reaction at various temperatures. XRD patterns confirm the wurtzite structure of the prepared samples. No peaks of other phases arising from impurities are detected in Mn- and Co-doped ZnO, hut the peaks of ZnFe204 and NiO are observed in Zno.99Feo.010 and Zno.99Nio.o10. The SEM observations indicate that with larger grain sizes than those of Zn0.99Feo.010 and Zno.99Ni0.010, Co-doped ZnO exhibits smooth grain surfaces. The infrared absorption spectra show that infrared absorptions related to oxygen in Zn0.99M0.010 are much stronger than those in Co-doped ZnO. Co ions are dissolved into the ZnO lattice with Co2＋ state from XPS spectra analysis. The infrared emissivity results imply that the emissivity of Zno.99Ni0.010 is the highest （0.829） and that of Zno.99C00.010 is the lowest （0.784） at 1 200 ℃. The emissivity of Zno.99Co0.010 decreases to the minimum （0.752） at 1 150 ℃ and then increases with growing calcination temperature. As the Co doping content grows, the emissivity of Co-doped ZnO calcined at 1 200 ℃ falls to 0.758 in the molar fraction of 3% and then ascends.展开更多
This paper deals with the radiation effects of different kinds ofradiant carriers used in making far infrared textile materials.From two radiation experiments,methods of testing radiation ef-fects of carriers have bee...This paper deals with the radiation effects of different kinds ofradiant carriers used in making far infrared textile materials.From two radiation experiments,methods of testing radiation ef-fects of carriers have been found,results of the experiments arediscussed.Finally,some conclusions for choosing appropriateradiant carrier are drawn.展开更多
文摘Quantum well intermixing techniques modify the geometric shape of quantum wells to allow postgrowth adjustments.The tuning effect on the optical response property of a GaAs/AlGaAs quantum well infrared photodetector(QWIP) induced by the interdifussion of Al atoms was studied theoretically.By assuming an improvement of the heterointerface quality and an enhanced Al interdiffusion caused by postgrowth intermixings,the photoluminescence spectrum shows a blue-shifted,narrower and enhanced photoluminescence peak.The infrared optical absorption spectrum also shows the expected redshift of the response wavelength.However,the variation in the absorption peak intensity depends on the boundary conditions of the photo generated carriers.For high-quality QWIP samples,the mean free path of photocarriers is long so that the photocarriers are largely coherent when they transport across quantum wells.In this case,the enhanced Al interdiffusion can significantly degrade the infrared absorption property of the QWIP.Special effects are therefore needed to maintain and/or improve the optical properties of the QWIP device during postgrowth treatments.
基金supported by the National Natural Science Foundation of China (No. 60561001)the Natural Science Foundation of Inner Mongolia Autonomous Region, China (No. 200408020105)+1 种基金the Program for New Century Excellent Talents in Universities (No. NCET-05-0272)College Science and Technology Re-search Project of Inner Mongolia Autonomous Region, China (No. NJ04094)
文摘The manganite perovskite polycrystal samples of （La1-xDyx）2/3Sr1/3MnO3 （x = 0, 0.1, 0.2, 0.35, and 0.5） doped with Dy were prepared by solid state reaction in atmosphere to measure their X-ray diffraction （XRD） patterns, scanning electric microscope （SEM） images, infrared absorption spectra, and microwave electromagnetic properties. The displacement of the XRD peaks of the samples was found, and the 2θ increases from 0.05o to 0.5o. The grains of undoped La2/3Sr1/3MnO3 not only have the greatest size, but also the most regular shape. The size of the grains decreases as the Dy doping content increases from 0 to 0.5. The infrared absorption spectra of all samples were measured at room temperature. An absorption peak corresponding to the stretching vibration mode of Mn-O bonds appears within the range of 591-629 cm-1. The absorption peak shifts from a higher frequency to a lower one with the decrease of the average ionic radius of A-site. The frequency de- pendence of microwave-absorbing properties, imaginary components of the complex magnetic permeability μ＂ and dielectric permeability ε＂ for all samples was measured at room temperature from 8 to 13 GHz. The results show that the loss of microwave absorption can be attrib- uted to both the magnetic and electric losses. The increase of Dy content not only enhances the microwave absorption but also causes the displacement of the absorption peaks.
文摘In the infrared spectrum absorbed type gas concentration sensor,voltage signal obtained from the two-channel thermopile infrared detector TPS2534 is very weak.In order to solve this problem,the authors have established the structure of the sensor and designed weak signal detecting circuit of the sensor based on infrared spectrum absorption principle,differential de-noising principle and weak signal detecting principle.The authors have made experiments using CH4 gas.The results show that the circuit can remove noise effectively and detect weak electrical signal obtained from the detector.
文摘Infrared （IR） absorption spectra and X-ray powder diffraction （XRD） patterrns of sexpenfine cat＇s eye from Sichuan Province have been investigated, and infrared absorption bands of the serpentine have been assigned in this paper. The results indicate that the bands near 3 600 - 3 700 cm^-1 belong to the stretching absorption band VOH, the bands in 948 - 1 100 cm^-1 axe assigned to the stretching vibraling band Usvo, and the bands at 600 570 and 440 cm^-1 respectively belong to the bending vibration band VOH, δMg-O and δSi-O. The serpentine cat＇ s eye includes two types： chrysotile and antigorite. Chrysotile has a sharp and intensive band at 3 688 cm^-1 and a weak band at 3 643 cm^-1 , while antigorite has only one intensive band in the region. At vibration band VSi-O, chrysotile and antigorite have a similar feature at 1 071 cm^-1, but the band at 980 cm^-1 in anfigorite has been split into two bands in chrysotile - a strong one at 1 027 cm^-1 and a weak one at 949 cm^-1. In addition, antigorite has a characteristic bending vibrating band δMg-O at 570 cm^-1. Based on the analysis of the feature of crystal structure, their IR differences axe well explained.
基金the financial support extended for this academic work by the Beijing Natural Science Foundation(Grant No.2232066)the Open Project Foundation of State Key Laboratory of Solid Lubrication(Grant No.LSL-2212)。
文摘The infrared(IR)absorption spectral data of 63 kinds of lubricating greases containing six different types of thickeners were obtained using the IR spectroscopy.The Kohonen neural network algorithm was used to identify the type of the lubricating grease.The results show that this machine learning method can effectively eliminate the interference fringes in the IR spectrum,and complete the feature selection and dimensionality reduction of the high-dimensional spectral data.The 63 kinds of greases exhibit spatial clustering under certain IR spectrum recognition spectral bands,which are linked to characteristic peaks of lubricating greases and improve the recognition accuracy of these greases.The model achieved recognition accuracy of 100.00%,96.08%,94.87%,100.00%,and 87.50%for polyurea grease,calcium sulfonate composite grease,aluminum(Al)-based grease,bentonite grease,and lithium-based grease,respectively.Based on the different IR absorption spectrum bands produced by each kind of lubricating grease,the three-dimensional spatial distribution map of the lubricating grease drawn also verifies the accuracy of classification while recognizing the accuracy.This paper demonstrates fast recognition speed and high accuracy,proving that the Kohonen neural network algorithm has an efficient recognition ability for identifying the types of the lubricating grease.
基金the Natural Science Foundation of Shandong Province, China. No. Y2005C31
文摘AIM： To prepare a complex of hyaluronic acid （HA） and phospholipids （PL）, and study the improvement effect of PL on the oral absorption of HA. METHODS： The complex of HA-PL （named Haplex） was prepared by film dispersion and sonication method, its physico-chemical properties were identified by infrared spectra and differential scanning calorimetry （DSC）. The oral absorption of Haplex was studied. Thirty-two healthy rats were divided into 4 groups randomly： （1） a normal saline （NS） control group; （2） an HA group; （3） a mixture group and （4） a Haplex group. After intragastric administration, the concentration of HA in serum was determined. RESULTS： The physico-chemical properties of Haplex were different from HA or PL or their mixture. After Haplex was administered to rats orally, the serum concentration of HA was increased when compared with the mixture or HA control groups from 4 h to 10 h （P 〈 0.05）. The AAUCo-12, of Haplex was also greater than that of the other three groups （P 〈 0.05）. CONCLUSION： The method of film dispersion and sonication can prepare HA and PL complex, and PL can enhance the oral absorption of exogenous HA.
基金Project(2009K06_03) supported by the Scientific and Technological Program of Shaanxi Province,China
文摘Infrared emissivity was studied in Zno.99Mo.olO （M is Mn, Fe or Ni） and Znl_xCoxO （x=0.01, 0.02, 0.03 and 0.04） powders synthesized by solid-state reaction at various temperatures. XRD patterns confirm the wurtzite structure of the prepared samples. No peaks of other phases arising from impurities are detected in Mn- and Co-doped ZnO, hut the peaks of ZnFe204 and NiO are observed in Zno.99Feo.010 and Zno.99Nio.o10. The SEM observations indicate that with larger grain sizes than those of Zn0.99Feo.010 and Zno.99Ni0.010, Co-doped ZnO exhibits smooth grain surfaces. The infrared absorption spectra show that infrared absorptions related to oxygen in Zn0.99M0.010 are much stronger than those in Co-doped ZnO. Co ions are dissolved into the ZnO lattice with Co2＋ state from XPS spectra analysis. The infrared emissivity results imply that the emissivity of Zno.99Ni0.010 is the highest （0.829） and that of Zno.99C00.010 is the lowest （0.784） at 1 200 ℃. The emissivity of Zno.99Co0.010 decreases to the minimum （0.752） at 1 150 ℃ and then increases with growing calcination temperature. As the Co doping content grows, the emissivity of Co-doped ZnO calcined at 1 200 ℃ falls to 0.758 in the molar fraction of 3% and then ascends.
文摘This paper deals with the radiation effects of different kinds ofradiant carriers used in making far infrared textile materials.From two radiation experiments,methods of testing radiation ef-fects of carriers have been found,results of the experiments arediscussed.Finally,some conclusions for choosing appropriateradiant carrier are drawn.
