| 1. |
- Duan, Zheng, et al.
(författare)
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Optical characterization of Chinese hybrid rice using laser-induced fluorescence techniques—laboratory and remote-sensing measurements
- 2018
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Ingår i: Applied Optics. - 1559-128X. ; 57:13, s. 3481-3487
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Tidskriftsartikel (refereegranskat)abstract
- Chinese hybrid rice of different varieties, growing in paddies in the Pingqiao district, north of Xinyang city, Henan province, China, was studied in detailed spectroscopic characteristics using laser-induced fluorescence. The base for the studies was the new South China Normal University mobile lidar laboratory, which was dispatched on site, providing facilities both for laboratory studies using a 405 nm excitation source as well as remote sensing measurements at ranges from around 40 m–120 m, mostly employing the 532 nm output from a Nd:YAG laser. We, in particular, studied the spectral influence of the species varieties as well as the level of nitrogen fertilization supplied. Specially developed contrast functions as well as multivariate techniques with principal components and Fisher’s discriminate analyses were applied, and useful characterization of the rice could be achieved. The chlorophyll content mapping of the 30 zones was obtained with the remote sensing measurements.
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| 2. |
- Brydegaard, Mikkel, et al.
(författare)
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The Scheimpflug lidar method
- 2017
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Ingår i: Lidar Remote Sensing for Environmental Monitoring 2017. - : SPIE. - 9781510612693 ; 10406
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Konferensbidrag (refereegranskat)abstract
- The recent several years we developed the Scheimpflug lidar method. We combined an invention from the 19th century with modern optoelectronics such as diode lasers and CMOS array from the 21st century. The approach exceeds expectations of background suppression, sensitivity and resolution beyond known from time-of-flight lidars. We accomplished multiband elastic atmospheric lidars for resolving single particles and aerosol plumes from 405 nm to 1550 nm. We pursued hyperspectral differential absorption lidar for molecular species. We demonstrated a simple method of inelastic hyperspectral lidar for profiling aquatic environments and vegetation structure. Not least, we have developed polarimetric Scheimpflug lidar with multi-kHz sampling rates for remote modulation spectroscopy and classification of aerofauna. All these advances are thanks to the Scheimpflug principle. Here we give a review of how far we have come and shed light on the limitations and opportunities for future directions. In particular, we show how the biosphere can be resolved with unsurpassed resolution in space and time, and share our expectation on how this can revolutionize ecological analysis and management in relation to agricultural pests, disease vectors and pollinator problematics.
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| 3. |
- Duan, Zheng, et al.
(författare)
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Aquatic environment monitoring using a drone-based fluorosensor
- 2019
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Ingår i: Applied Physics B: Lasers and Optics. - : Springer Science and Business Media LLC. - 0946-2171. ; 125
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Tidskriftsartikel (refereegranskat)abstract
- A drone-based system for monitoring of laser-induced fluorescence from the aquatic environment was constructed. Fixed-range remote-sensing demonstration measurements were performed, and field recordings of natural river water fluorescence, oil-slicks as well as dye-marked natural water volumes were taken at drone flying heights of about 10 m. Our fluorosensor, weighing only 1.5 kg, and carried by a commercial drone, illustrates how airborne remote sensing based on fluorescence can be made cost-effective and readily applicable, while presently only in ambient low-light-level conditions.
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| 4. |
- Duan, Zheng, et al.
(författare)
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Atmospheric mercury pollution in the xi’an area, china, studied by differential absorption lidar
- 2021
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Ingår i: Atmosphere. - : MDPI AG. - 2073-4433. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of the atmospheric concentration of polluting atomic mercury were performed using the differential absorption lidar (DIAL) technique in the Lintong district, about 35 km northeast of Xi’an, the capital of the Shaanxi province, China. Concentrations ranging from 2 to 13 ng/m3 were observed. As uniquely enabled by the lidar technique, representative average concentrations, integrated over a considerable volume, were recorded and put in relation to weather conditions, and vertical concentration profiles were measured. Considerable local non-uniformities were also observed, which may indicate the presence of localized hot-spots in the area, possibly related to ancient tombs.
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| 5. |
- Duan, Zheng, et al.
(författare)
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Remote LIBS Measurements on Metals Using a Mobile Lidar System
- 2018
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Ingår i: 2018 Asia Communications and Photonics Conference, ACP 2018. - 9781538661581 ; 2018-October
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Konferensbidrag (refereegranskat)abstract
- The preliminary remote laser-induced breakdown spectroscopy measurement of metals is performed on a mobile lidar system. The Nd:YAG laser synchronized with an ICCD spectrometer, the detection range can be achieved up to 45 m.
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| 6. |
- Hu, Lingna, et al.
(författare)
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Optical detection of otitis media using modified spectroscopic otoscope
- 2018
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Ingår i: 2018 Asia Communications and Photonics Conference, ACP 2018. - 9781538661581 ; 2018-October
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Konferensbidrag (refereegranskat)abstract
- Otitis media is a common infectious disease in early childhood. We use an optical diagnostic system combining otoscopy and spectroscopy to improve the accuracy of diagnosis of otitis media.
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| 7. |
- Hudson, Thomas J., et al.
(författare)
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International network of cancer genome projects
- 2010
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 464:7291, s. 993-998
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Tidskriftsartikel (refereegranskat)abstract
- The International Cancer Genome Consortium (ICGC) was launched to coordinate large-scale cancer genome studies in tumours from 50 different cancer types and/or subtypes that are of clinical and societal importance across the globe. Systematic studies of more than 25,000 cancer genomes at the genomic, epigenomic and transcriptomic levels will reveal the repertoire of oncogenic mutations, uncover traces of the mutagenic influences, define clinically relevant subtypes for prognosis and therapeutic management, and enable the development of new cancer therapies.
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| 8. |
- Lian, Ming, et al.
(författare)
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Lidar mapping of atmospheric atomic mercury in the Wanshan area, China
- 2018
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Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491. ; 240, s. 353-358
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Tidskriftsartikel (refereegranskat)abstract
- A novel mobile laser radar system was used for mapping gaseous atomic mercury (Hg0) atmospheric pollution in the Wanshan district, south of Tongren City, Guizhou Province, China. This area is heavily impacted by legacy mercury from now abandoned mining activities. Differential absorption lidar measurements were supplemented by localized point monitoring using a Lumex RA-915M Zeeman modulation mercury analyzer. Range-resolved concentration measurements in different directions were performed. Concentrations in the lower atmospheric layers often exceeded levels of 100 ng/m3 for March conditions with temperature ranging from 5 °C to 20 °C. A flux measurement of Hg0 over a vertical cross section of 0.12 km2 resulted in about 29 g/h. Vertical lidar sounding at night revealed quickly falling Hg0 concentrations with height. This is the first lidar mapping demonstration in a heavily mercury-polluted area in China, illustrating the lidar potential in complementing point monitors.
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| 9. |
- Lin, Xiaobo, et al.
(författare)
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Ripening of avocado fruits studied by spectroscopic techniques
- 2020
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Ingår i: Journal of Biophotonics. - : Wiley. - 1864-063X .- 1864-0648. ; 13:8
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Tidskriftsartikel (refereegranskat)abstract
- Avocados are considered very healthy due to the high content mono-unsaturated lipid, essential vitamins and minerals, minimal sugar and no cholesterol and are therefore sometimes referred to as “the perfect fruits”. Avocados, mainly grown in Latin-America, are harvested unripe and sent overseas. However, the ripening process is very difficult to assess visually and tactilely. A tool for precise noninvasive judgment of the status would be valuable as the fruit is too expensive to be cut open unripe or overdue. A white-light source and a light-emitting diode unit with four excitation wavelengths (365, 385, 395, and 405 nm) were used for reflectance and fluorescence spectroscopy in a fiber-coupled set-up for noninvasive monitoring. Twelve non-ripe avocados, with approximately the same size and appearance, were studied and divided into three groups and kept at three different storage conditions; at room temperature, in a refrigerator and a combination of the two. We showed that fluorescence was useful for following the ripening process. A method, which compensates for the spatial variations in spectral properties around a fruit, is described. Remote fluorescence monitoring, intended for orchard use, was also demonstrated. A low-cost device based on fluorescence for avocado ripeness assessment is proposed.
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| 10. |
- Lu, Junchen, et al.
(författare)
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Monitoring of flying insects using a dual-wavelength CW lidar system
- 2019
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Ingår i: 2019 Asia Communications and Photonics Conference, ACP 2019 - Proceedings. - 2162-108X. - 9781943580705 ; 2019-November
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Konferensbidrag (refereegranskat)abstract
- A dual-wavelength continuous-wave lidar based on the Scheimpflug principle was employed to study the diurnal insect activity above a lake in South China. Insect numbers, wingbeat frequencies and reflectance sensitivity to different wavelengths were investigated.
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