Xinli Wang, Wei Gao, K. R. Reddy, J. Slusser, Min Xu
Field experiments and laboratory tests have shown multiple effects of enhanced ultraviolet-B (UV-B) radiation on cotton growth, development, and yield. Adverse effects include development of chlorotic and necrotic patches on leaves, reductions in total leaf area, plant height, photosynthesis, and yield. However, little work has been carried out to incorporate these experimental results into a simulation model and to estimate the effects of UV-B radiation under field conditions with varied environments and management practices. This study incorporates experimental results of UV-B effects on cotton crop into a cotton simulation model, GOSSYM, which is being used widely in various applications. In this work, first modules were modified to incorporate the effects of UV-B radiation on canopy photosynthesis, leaf area expansion, and stem and branch elongation. Then, the modified model was used to test the validity of model assumptions and algorithms on independent experimental data sets. Finally, preliminary studies were performed to simulate the effects of UV-B radiation in the field conditions at Stoneville, Mississippi using 30-year (1964-1993) climate data. Simulation results agreed well with experimental measurements, proving the validation of the model. Our results suggest that cotton lint yield declined with increased UV-B radiation. The reductions were 20% when UV-B irradiance was 12 kJ m-2 under irrigated conditions. Similar reductions in yield were predicted at lower UV-B radiation (11 kJ m-2) under rain-fed conditions. The modified model will be useful to simulate the impacts of UV-B radiation on cotton growth and yield under current and future climatic conditions and to suggest management options to mitigate the adverse effects.
{"title":"Preliminary results of a UV-B effect incorporated GOSSYM model","authors":"Xinli Wang, Wei Gao, K. R. Reddy, J. Slusser, Min Xu","doi":"10.1117/12.681446","DOIUrl":"https://doi.org/10.1117/12.681446","url":null,"abstract":"Field experiments and laboratory tests have shown multiple effects of enhanced ultraviolet-B (UV-B) radiation on cotton growth, development, and yield. Adverse effects include development of chlorotic and necrotic patches on leaves, reductions in total leaf area, plant height, photosynthesis, and yield. However, little work has been carried out to incorporate these experimental results into a simulation model and to estimate the effects of UV-B radiation under field conditions with varied environments and management practices. This study incorporates experimental results of UV-B effects on cotton crop into a cotton simulation model, GOSSYM, which is being used widely in various applications. In this work, first modules were modified to incorporate the effects of UV-B radiation on canopy photosynthesis, leaf area expansion, and stem and branch elongation. Then, the modified model was used to test the validity of model assumptions and algorithms on independent experimental data sets. Finally, preliminary studies were performed to simulate the effects of UV-B radiation in the field conditions at Stoneville, Mississippi using 30-year (1964-1993) climate data. Simulation results agreed well with experimental measurements, proving the validation of the model. Our results suggest that cotton lint yield declined with increased UV-B radiation. The reductions were 20% when UV-B irradiance was 12 kJ m-2 under irrigated conditions. Similar reductions in yield were predicted at lower UV-B radiation (11 kJ m-2) under rain-fed conditions. The modified model will be useful to simulate the impacts of UV-B radiation on cotton growth and yield under current and future climatic conditions and to suggest management options to mitigate the adverse effects.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128548805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The potential of digital image processing for weed mapping in arable crops has widely been investigated in the last decades. In grassland farming these techniques are rarely applied so far. The project presented here focuses on the automatic identification of one of the most invasive and persistent grassland weed species, the broad-leaved dock (Rumex obtusifolius L.) in complex mixtures of grass and herbs. A total of 108 RGB-images were acquired in near range from a field experiment under constant illumination conditions using a commercial digital camera. The objects of interest were separated from the background by transforming the 24 bit RGB-images into 8 bit intensities and then calculating the local homogeneity images. These images were binarised by applying a dynamic grey value threshold. Finally, morphological opening was applied to the binary images. The remaining contiguous regions were considered to be objects. In order to classify these objects into 3 different weed species, a soil and a residue class, a total of 17 object-features related to shape, color and texture of the weeds were extracted. Using MANOVA, 12 of them were identified which contribute to classification. Maximum-likelihood classification was conducted to discriminate the weed species. The total classification rate across all classes ranged from 76 % to 83 %. The classification of Rumex obtusifolius achieved detection rates between 85 % and 93 % by misclassifications below 10 %. Further, Rumex obtusifolius distribution and the density maps were generated based on classification results and transformation of image coordinates into Gauss-Krueger system. These promising results show the high potential of image analysis for weed mapping in grassland and the implementation of site-specific herbicide spraying.
{"title":"Image classification approach for automatic identification of grassland weeds","authors":"S. Gebhardt, W. Kühbauch","doi":"10.1117/12.678752","DOIUrl":"https://doi.org/10.1117/12.678752","url":null,"abstract":"The potential of digital image processing for weed mapping in arable crops has widely been investigated in the last decades. In grassland farming these techniques are rarely applied so far. The project presented here focuses on the automatic identification of one of the most invasive and persistent grassland weed species, the broad-leaved dock (Rumex obtusifolius L.) in complex mixtures of grass and herbs. A total of 108 RGB-images were acquired in near range from a field experiment under constant illumination conditions using a commercial digital camera. The objects of interest were separated from the background by transforming the 24 bit RGB-images into 8 bit intensities and then calculating the local homogeneity images. These images were binarised by applying a dynamic grey value threshold. Finally, morphological opening was applied to the binary images. The remaining contiguous regions were considered to be objects. In order to classify these objects into 3 different weed species, a soil and a residue class, a total of 17 object-features related to shape, color and texture of the weeds were extracted. Using MANOVA, 12 of them were identified which contribute to classification. Maximum-likelihood classification was conducted to discriminate the weed species. The total classification rate across all classes ranged from 76 % to 83 %. The classification of Rumex obtusifolius achieved detection rates between 85 % and 93 % by misclassifications below 10 %. Further, Rumex obtusifolius distribution and the density maps were generated based on classification results and transformation of image coordinates into Gauss-Krueger system. These promising results show the high potential of image analysis for weed mapping in grassland and the implementation of site-specific herbicide spraying.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"80 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114003327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Richard K. Martin, A. Sharkawy, J. Humphrey, E. Kelmelis, D. Prather
There is a growing need for miniature low-cost chemical sensors for use in monitoring environmental conditions. Applications range from environmental pollution monitoring, industrial process control and homeland security threat detection to biomedical diagnostics. Integrated opto-chemical sensors can provide the required functionality by monitoring chemistry induced changes in the refractive, absorptive, or luminescent properties of materials. Mach-Zehnder (MZ) interferometers, using the phase induced from a chemically reactive film, have shown success for such applications but typically are limited to one chemical analysis per sensor. In this paper we present a MZ-like sensor using the dispersion properties of a photonic crystal lattice. Properly engineered dispersion guiding enables the creation of multiple parallel MZ-like sensors monitoring different chemical reactions in a device much smaller than a typical MZ sensor. The phase shift induced in one arm of the photonic crystal structure by the chemical reaction of a special film induces a change in the sensor output. The use of a dispersion guiding photonic crystal structure enables the use of lower refractive index materials because the creation of a bandgap is not necessary. This in turn increases coupling efficiency into the device. Other advantages of this type of structure include the ability to guide both TE and TM modes as well as reduced sensitivity to fabrication tolerances. Two-dimensional FDTD analysis is used to optimize and model the effectiveness of the structure.
{"title":"Integrated optical chemical sensor using a dispersion-guided photonic crystal structure","authors":"Richard K. Martin, A. Sharkawy, J. Humphrey, E. Kelmelis, D. Prather","doi":"10.1117/12.681136","DOIUrl":"https://doi.org/10.1117/12.681136","url":null,"abstract":"There is a growing need for miniature low-cost chemical sensors for use in monitoring environmental conditions. Applications range from environmental pollution monitoring, industrial process control and homeland security threat detection to biomedical diagnostics. Integrated opto-chemical sensors can provide the required functionality by monitoring chemistry induced changes in the refractive, absorptive, or luminescent properties of materials. Mach-Zehnder (MZ) interferometers, using the phase induced from a chemically reactive film, have shown success for such applications but typically are limited to one chemical analysis per sensor. In this paper we present a MZ-like sensor using the dispersion properties of a photonic crystal lattice. Properly engineered dispersion guiding enables the creation of multiple parallel MZ-like sensors monitoring different chemical reactions in a device much smaller than a typical MZ sensor. The phase shift induced in one arm of the photonic crystal structure by the chemical reaction of a special film induces a change in the sensor output. The use of a dispersion guiding photonic crystal structure enables the use of lower refractive index materials because the creation of a bandgap is not necessary. This in turn increases coupling efficiency into the device. Other advantages of this type of structure include the ability to guide both TE and TM modes as well as reduced sensitivity to fabrication tolerances. Two-dimensional FDTD analysis is used to optimize and model the effectiveness of the structure.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114560303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. O’Connor, D. Wagenaar, C. Hruska, S. Phillips, G. Caravaglia, D. Rhodes
In women with radiographically dense breasts, the sensitivity of mammography is less than 50%. With the increase in the percent of women with dense breasts, it is important to look at alternative screening techniques for this population. This article reviews the strengths and weaknesses of current imaging techniques and focuses on recent developments in semiconductor-based gamma camera systems that offer significant improvements in image quality over that achievable with single-crystal sodium iodide systems. We have developed a technique known as Molecular Breast Imaging (MBI) using small field of view Cadmium Zinc Telluride (CZT) gamma cameras that permits the breast to be imaged in a similar manner to mammography, using light pain-free compression. Computer simulations and experimental studies have shown that use of low-energy high sensitivity collimation coupled with the excellent energy resolution and intrinsic spatial resolution of CZT detectors provides optimum image quality for the detection of small breast lesions. Preliminary clinical studies with a prototype dual-detector system have demonstrated that Molecular Breast Imaging has a sensitivity of ~90% for the detection of breast tumors less than 10 mm in diameter. By comparison, conventional scintimammography only achieves a sensitivity of 50% in the detection of lesions < 10 mm. Because Molecular Breast Imaging is not affected by breast density, this technique may offer an important adjunct to mammography in the evaluation of women with dense breast parenchyma.
{"title":"Molecular breast imaging using a dedicated high-performance instrument","authors":"M. O’Connor, D. Wagenaar, C. Hruska, S. Phillips, G. Caravaglia, D. Rhodes","doi":"10.1117/12.687621","DOIUrl":"https://doi.org/10.1117/12.687621","url":null,"abstract":"In women with radiographically dense breasts, the sensitivity of mammography is less than 50%. With the increase in the percent of women with dense breasts, it is important to look at alternative screening techniques for this population. This article reviews the strengths and weaknesses of current imaging techniques and focuses on recent developments in semiconductor-based gamma camera systems that offer significant improvements in image quality over that achievable with single-crystal sodium iodide systems. We have developed a technique known as Molecular Breast Imaging (MBI) using small field of view Cadmium Zinc Telluride (CZT) gamma cameras that permits the breast to be imaged in a similar manner to mammography, using light pain-free compression. Computer simulations and experimental studies have shown that use of low-energy high sensitivity collimation coupled with the excellent energy resolution and intrinsic spatial resolution of CZT detectors provides optimum image quality for the detection of small breast lesions. Preliminary clinical studies with a prototype dual-detector system have demonstrated that Molecular Breast Imaging has a sensitivity of ~90% for the detection of breast tumors less than 10 mm in diameter. By comparison, conventional scintimammography only achieves a sensitivity of 50% in the detection of lesions < 10 mm. Because Molecular Breast Imaging is not affected by breast density, this technique may offer an important adjunct to mammography in the evaluation of women with dense breast parenchyma.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116656692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper we report on the simulation, design, and testing of high performance CdZnTe quasi-hemispherical CAPtureTM Plus radiation detectors. Quasi-hemispherical CdZnTe detectors offer a cost effective alternative to other single-polarity (electron-only) detector configurations such as co-planar grid, pixilated or Frish ring CdZnTe detectors with comparable energy resolution both in the high (>500 keV) and low energy range (<500 keV). We have used the device simulation package eVDSIM to design optimal electrode geometry together with the necessary material selection criteria for charge transport properties of the CdZnTe crystals. A test set of 10x10x5mm3 CAPtureTM Plus detectors has been built using state-of-the art fabrication technology. The measured spectral and efficiency performance of these detectors is compared to the theoretical predictions of simulation. Our results demonstrate that with careful selection of uniform material and high-quality fabrication, this design of CAPtureTM Plus detectors is capable of regularly achieving FWHM @ 81keV of 5%, FWHM @ 122keV of <3%, and FWHM @ 662keV of <2%.
{"title":"Design of high-performance CdZnTe quasi-hemispherical gamma-ray CAPture plus detectors","authors":"D. Bale, C. Szeles","doi":"10.1117/12.683702","DOIUrl":"https://doi.org/10.1117/12.683702","url":null,"abstract":"In this paper we report on the simulation, design, and testing of high performance CdZnTe quasi-hemispherical CAPtureTM Plus radiation detectors. Quasi-hemispherical CdZnTe detectors offer a cost effective alternative to other single-polarity (electron-only) detector configurations such as co-planar grid, pixilated or Frish ring CdZnTe detectors with comparable energy resolution both in the high (>500 keV) and low energy range (<500 keV). We have used the device simulation package eVDSIM to design optimal electrode geometry together with the necessary material selection criteria for charge transport properties of the CdZnTe crystals. A test set of 10x10x5mm3 CAPtureTM Plus detectors has been built using state-of-the art fabrication technology. The measured spectral and efficiency performance of these detectors is compared to the theoretical predictions of simulation. Our results demonstrate that with careful selection of uniform material and high-quality fabrication, this design of CAPtureTM Plus detectors is capable of regularly achieving FWHM @ 81keV of 5%, FWHM @ 122keV of <3%, and FWHM @ 662keV of <2%.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114503642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Zych, T. O'Neill, D. Bhattacharya, C. Trojanowski, S. Wijeratne, C. Teichegaeber, M. Mathews
The prototype TIGRE Tracking and Imaging Gamma-Ray Experiment is being prepared for a scientific balloon flight in fall, 2006. TIGRE is a Compton telescope for 0.5-10 MeV gamma rays and a pair telescope for 10-100 MeV gammas. It uses multiple layers of thin silicon strip detectors as both the Compton and pair converter and the charged particle tracker. The event coincidence requirement is completed with arrays of CsI(Tl)-photodiode detectors surrounding the converter/tracker and large Na(Tl)-PMT detectors below. The purpose of this flight is to demonstrate the background suppression capabilities of the TIGRE instrument with Compton recoil electron tracking and the improved angular resolution for pairs with silicon as the converter material. Details of the control and readout of the detectors will be described. Calibration results using laboratory radioisotopes will likewise be presented.
{"title":"TIGRE prototype gamma-ray balloon instrument","authors":"A. Zych, T. O'Neill, D. Bhattacharya, C. Trojanowski, S. Wijeratne, C. Teichegaeber, M. Mathews","doi":"10.1117/12.683838","DOIUrl":"https://doi.org/10.1117/12.683838","url":null,"abstract":"The prototype TIGRE Tracking and Imaging Gamma-Ray Experiment is being prepared for a scientific balloon flight in fall, 2006. TIGRE is a Compton telescope for 0.5-10 MeV gamma rays and a pair telescope for 10-100 MeV gammas. It uses multiple layers of thin silicon strip detectors as both the Compton and pair converter and the charged particle tracker. The event coincidence requirement is completed with arrays of CsI(Tl)-photodiode detectors surrounding the converter/tracker and large Na(Tl)-PMT detectors below. The purpose of this flight is to demonstrate the background suppression capabilities of the TIGRE instrument with Compton recoil electron tracking and the improved angular resolution for pairs with silicon as the converter material. Details of the control and readout of the detectors will be described. Calibration results using laboratory radioisotopes will likewise be presented.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130377269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We report a numerical analysis of the liquid crystal polarization grating (LCPG) as an electro-optically controlled, polarization independent light modulator. The 2D finite-difference time-domain (FDTD) modeling for periodic anisotropic structures has been developed as a numerical tool to study optical properties of anisotropic gratings. Both normal and oblique incidence cases are successfully implemented for wide-band analysis. Nematic director profiles of the LCPG are obtained from elastic free-energy calculations using a commercial software tool, called LC3D. A study of the essential diffraction characteristics of the LCPG is presented, which manifests pixel-level light modulation with a nearly 100% efficiency on unpolarized light. The effect of an off-axis input and the grating regime on the LCPG diffraction is investigated. Finally, we present a study of the electro-optical response of the LCPG when an electric field applied for both static and dynamic cases. The FDTD results show that a highly efficient, polarization-independent light modulation with capability of an electrical switching/tuning is possible by the LCPG.
{"title":"FDTD analysis of 100% efficient polarization-independent liquid crystal polarization grating","authors":"C. Oh, Ravi K. Komanduri, M. Escuti","doi":"10.1117/12.681357","DOIUrl":"https://doi.org/10.1117/12.681357","url":null,"abstract":"We report a numerical analysis of the liquid crystal polarization grating (LCPG) as an electro-optically controlled, polarization independent light modulator. The 2D finite-difference time-domain (FDTD) modeling for periodic anisotropic structures has been developed as a numerical tool to study optical properties of anisotropic gratings. Both normal and oblique incidence cases are successfully implemented for wide-band analysis. Nematic director profiles of the LCPG are obtained from elastic free-energy calculations using a commercial software tool, called LC3D. A study of the essential diffraction characteristics of the LCPG is presented, which manifests pixel-level light modulation with a nearly 100% efficiency on unpolarized light. The effect of an off-axis input and the grating regime on the LCPG diffraction is investigated. Finally, we present a study of the electro-optical response of the LCPG when an electric field applied for both static and dynamic cases. The FDTD results show that a highly efficient, polarization-independent light modulation with capability of an electrical switching/tuning is possible by the LCPG.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"512 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122902383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Schmidt, A. Petrov, J. Wülbern, M. Eich, U. Huebner, R. Boucher
We report on electrooptical modulation with a sub 1Volt sensititivity in a photonic crystal slab waveguide resonator which contains a nanostructured nonlinear optical polymer. This modulation effect is based on the electronic displacement polarization in a noncentrosymmetric medium (Pockels-effect) and is therefore inherently by more than three orders of magnitude faster than any other reported electrooptic modulation effect in nanophotonics. We also show concepts for extremely high and zero dispersion as well as for time delay in photonic crystal waveguides. Tuning can be achieved by hybrid combination of Si-based PCs and organic EO-materials.
{"title":"Modulation and dispersion control in photonic crystals","authors":"M. Schmidt, A. Petrov, J. Wülbern, M. Eich, U. Huebner, R. Boucher","doi":"10.1117/12.684095","DOIUrl":"https://doi.org/10.1117/12.684095","url":null,"abstract":"We report on electrooptical modulation with a sub 1Volt sensititivity in a photonic crystal slab waveguide resonator which contains a nanostructured nonlinear optical polymer. This modulation effect is based on the electronic displacement polarization in a noncentrosymmetric medium (Pockels-effect) and is therefore inherently by more than three orders of magnitude faster than any other reported electrooptic modulation effect in nanophotonics. We also show concepts for extremely high and zero dispersion as well as for time delay in photonic crystal waveguides. Tuning can be achieved by hybrid combination of Si-based PCs and organic EO-materials.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131937046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jihua Sun, B. Baker, D. Bachelet, C. Daly, Jian Ma, Jianyu Liu
Alpine meadows in the Hengduan Mountains of northwestern Yunnan, P.R. China are incredibly diverse. The regional climate is warming at a relatively rapid rate. In this paper, analyses of historical climate station data show that mean annual temperature over the last two decades has increased at a rate of 0.6°C/10 yr. In addition, analyses of historical remote sensing data show that the vegetation distribution in this region has changed evidently. We present simulation results from a general circulation model (HadCM3) and a dynamic vegetation model (MC1) showing how changes in future climate may alter alpine ecosystem of the Baima Nature Reserve in northwestern Yunnan.
{"title":"Impact of climate change in the Hengduan Mountains of northwestern Yunnan, P.R. China: vegetation distribution change in the foretime and future","authors":"Jihua Sun, B. Baker, D. Bachelet, C. Daly, Jian Ma, Jianyu Liu","doi":"10.1117/12.678964","DOIUrl":"https://doi.org/10.1117/12.678964","url":null,"abstract":"Alpine meadows in the Hengduan Mountains of northwestern Yunnan, P.R. China are incredibly diverse. The regional climate is warming at a relatively rapid rate. In this paper, analyses of historical climate station data show that mean annual temperature over the last two decades has increased at a rate of 0.6°C/10 yr. In addition, analyses of historical remote sensing data show that the vegetation distribution in this region has changed evidently. We present simulation results from a general circulation model (HadCM3) and a dynamic vegetation model (MC1) showing how changes in future climate may alter alpine ecosystem of the Baima Nature Reserve in northwestern Yunnan.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"6296 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130074909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Fischer, D. Neshev, W. Krolikowski, Y. Kivshar, D. Iturbe-Castillo, S. Chávez-Cerda, M. Meneghetti, D. P. Caetano, J. Hickmann
We report on the first experimental observation of a large spatial lateral shift in the interaction of obliquely oriented spatial-dark soliton stripes. We demonstrate by numerical simulations that this new effect can be attributed to the specific features of optical media with nonlocal nonlinear response.
{"title":"Observation of spatial phase shift in dark soliton crossing","authors":"R. Fischer, D. Neshev, W. Krolikowski, Y. Kivshar, D. Iturbe-Castillo, S. Chávez-Cerda, M. Meneghetti, D. P. Caetano, J. Hickmann","doi":"10.1117/12.681099","DOIUrl":"https://doi.org/10.1117/12.681099","url":null,"abstract":"We report on the first experimental observation of a large spatial lateral shift in the interaction of obliquely oriented spatial-dark soliton stripes. We demonstrate by numerical simulations that this new effect can be attributed to the specific features of optical media with nonlocal nonlinear response.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122092243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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