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11.
Forest cover change and illegal logging in the Ukrainian Carpathians in the transition period from 1988 to 2007 总被引:2,自引:0,他引:2
Tobias Kuemmerle Oleh Chaskovskyy Volker C. Radeloff William S. Keeton 《Remote sensing of environment》2009,113(6):1194-3809
Illegal logging is a major environmental and economic problem, and exceeds in some countries the amounts of legally harvested timber. In Eastern Europe and the former Soviet Union, illegal logging increased and reforestation on abandoned farmland was widespread after the breakdown of socialism, and the region's forest cover trends remain overall largely unclear. Our goal here was to map forest cover change and to assess the extent of illegal logging and reforestation in the Ukrainian Carpathians. We used Landsat TM/ETM+ images and Support Vector Machines (SVM) to derive forest change trajectories between 1988 and 2007 for the entire Ukrainian Carpathians. We calculated logging and reforestation rates, and compared Landsat-based forest trends to official statistics and inventory maps. Our classification resulted in reliable forest/non-forest maps (overall accuracies between 97.1%-98.01%) and high clear cut detection rates (on average 89.4%). Forest cover change was widespread in the Ukrainian Carpathians between 1988 and 2007. We found forest cover increase in peripheral areas, forest loss in the interior Carpathians, and increased logging in remote areas. Overall, our results suggest that unsustainable forest use from socialist times likely persisted in the post-socialist period, resulting in a continued loss of older forests and forest fragmentation. Landsat-based forest trends differed substantially from official forest resource statistics. Illegal logging appears to have been at least as extensive as documented logging during the early 1990s and so-called sanitary clear-cuts represent a major loophole for overharvesting and logging in restricted areas. Reforestation and illegal logging are frequently not accounted for in forest resource statistics, highlighting limitations of these data. Combating illegal logging and transitioning towards sustainable forestry requires better monitoring and up-to-date accounting of forest resources, in the Carpathians and elsewhere in Eastern Europe, and remote sensing can be a key technology to achieve these goals. 相似文献
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Vitalii Serdiuk Oleh Shevchuk Natalya Bukartyk Tetiana Kovalenko Anatolii Borysiuk Viktor Tokarev 《应用聚合物科学杂志》2021,138(36):50928
Magnetite nanoparticles (Fe3O4 NPs) with peroxide-containing polymer shell have been synthesized using the method of coprecipitation from the mixture solutions of Fe (II) and Fe (III) salts in the presence of peroxide-containing copolymer (PCC). Polymer shell presence has been proved by elemental and complex thermal analysis. Synthesized Fe3O4 NPs possess superparamagnetic properties. Their specific saturation magnetization decreases gradually from 65 to 54 A·m2·kg−1 with increasing PCC concentration owing to the surface spin pinning effect caused by a polymer shell. The average sizes of Fe3O4 NPs estimated from the data of XRD analysis and magnetic measurements are in the range of 9–12 nm. The NP sizes determined by the DLS method lie in the range of 150–270 nm; this result is significantly larger than the sizes estimated by the two aforementioned methods evidencing a tendency for Fe3O4 NPs toward self-association. Cross-linked composite films based on polyvinyl alcohol have been obtained via radical curing initiated by the PCC shell of nanoparticles. The resulting composite films are magnetically sensitive films with rather high physico-mechanical properties (tensile strength reaches 48–67 MPa and relative elongation – 4%–21% depending on cross-linking degree), a priori non-toxic and biocompatible, which makes them promising materials for various applications. 相似文献
13.
In the chemical-process industries, dilute streams containing valuable ingredients are generated in several unit operations. Mechanical vapor-recompression is the best available technology for vaporization that may be used for concentrating such dilute solutions. Energy consumption for vaporization by compression and membrane technology is 350 and 90 kJ/kg, respectively. In order to save additional energy by recycling water, this study explored the use of membranes for processing a hot feed (70–80°C) containing small amounts of food ingredients. Pilot tests report the effects of experimental parameters on membrane performance. The impact of pretreatment of the feed and membrane-cleaning procedures to maintain performance will also be discussed. Initial results indicate that the use of a membrane to pre-concentrate, prior to the final concentration with mechanical vapor recompression, has the potential to save significant amounts of energy. Furthermore, the use of membranes would increase plant capacity by reducing the load on the vapor-compression unit. In this study, it was estimated that a plant processing 15 metric tonnes of feed every day and using membrane technology for concentrating to twice the concentraiton would save about 2 GJ of energy. 相似文献
14.
Integrated temperature-humidity-sensitive thick-film structures based on spinel-type semiconducting ceramics of different chemical compositions and magnesium aluminate ceramics were prepared and studied. It is shown that temperature-sensitive thick-film structures possess good electrophysical characteristics in the region from 298 to 358 K. The change of electrical resistance in integrated thick-film structures is 1 order, but these elements are stable in time and can be successfully used for sensor applications. 相似文献
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Christian Behm Michael Nemec Fabian Weissinger Marco Aoqi Rausch Oleh Andrukhov Erwin Jonke 《International journal of molecular sciences》2021,22(13)
Background: During orthodontic tooth movement (OTM), applied orthodontic forces cause an extensive remodeling of the extracellular matrix (ECM) in the periodontal ligament (PDL). This is mainly orchestrated by different types of matrix metalloproteinases (MMPs) and their tissue inhibitors of matrix metalloproteinases (TIMPs), which are both secreted by periodontal ligament (PDL) fibroblasts. Multiple in vitro and in vivo studies already investigated the influence of applied orthodontic forces on the expression of MMPs and TIMPs. The aim of this systematic review was to explore the expression levels of MMPs and TIMPs during OTM and the influence of specific orthodontic force-related parameters. Methods: Electronic article search was performed on PubMed and Web of Science until 31 January 2021. Screenings of titles, abstracts and full texts were performed according to PRISMA, whereas eligibility criteria were defined for in vitro and in vivo studies, respectively, according to the PICO schema. Risk of bias assessment for in vitro studies was verified by specific methodological and reporting criteria. For in vivo studies, risk of bias assessment was adapted from the Joanna Briggs Institute Critical Appraisal Checklist for analytical cross-sectional study. Results: Electronic article search identified 3266 records, from which 28 in vitro and 12 in vivo studies were included. The studies showed that orthodontic forces mainly caused increased MMPs and TIMPs expression levels, whereas the exact effect may depend on various intervention and sample parameters and subject characteristics. Conclusion: This systematic review revealed that orthodontic forces induce a significant effect on MMPs and TIMPs in the PDL. This connection may contribute to the controlled depletion and formation of the PDLs’ ECM at the compression and tension site, respectively, and finally to the highly regulated OTM. 相似文献
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Yulia V. Yermolayeva Alexander V. TolmachevMaria V. Dobrotvorskaya Oleh M. Vovk 《Journal of Alloys and Compounds》2011,509(17):5320-5325
Monodisperse non-agglomerated Lu2O3:Eu3+ submicrometer spheres were obtained by the homogeneous precipitation technique with subsequent annealing for spheres crystallization. The morphological and structural parameters of the Lu2O3:Eu3+ crystalline spheres prepared were investigated by the electron microscopy methods, thermal analysis (TG-DTA), X-ray diffractometry (XRD), X-ray photoelectron (XPS) and FT-IR spectroscopy. The influence of the annealing temperature on the morphology and sphericity was shown. Eu3+-doped lutetium oxide spheres were characterized by effective luminescence under X-ray excitation in the λ = 575-725 nm range corresponding to 5D0 → 7FJ transitions (J = 0-4) of Eu3+ ions. It was shown that the X-ray luminescence efficiency of the Lu2O3:Eu3+ spherical phosphors prepared strongly depend on annealing temperature and dopant concentration. 相似文献
18.
Nigel R. Farrar David C. Brandt Igor V. Fomenkov Alex I. Ershov Norbert R. Bowering William N. Partlo David W. Myers Alexander N. Bykanov Georgiy O. Vaschenko Oleh V. Khodykin Jerzy R. Hoffman Christopher P. Chrobak 《Microelectronic Engineering》2009,86(4-6):509-512
This paper describes the development of a LPP EUV source using a CO2 laser with tin droplet targets. Burst power of 100 W and average power of 25 W has been achieved. Collector mirrors have been fabricated with >50% reflectivity and show stable EUV images. Multiple debris mitigation techniques preserve mirror reflectivity. Manufacturing of the first production systems is in progress. 相似文献
19.
Gefen S Tretiak O Bertrand L Rosen GD Nissanov J 《IEEE transactions on bio-medical engineering》2004,51(7):1230-1241
An algorithm for nonlinear registration of an elastic body is developed. Surfaces (outlines) of known anatomic structures are used to align all other (internal) points. The deformation field is represented with a multiresolution wavelet expansion and is modeled by the partial differential equations of linear elasticity. A hierarchical approach that reduces algorithm complexity is adopted. The performance of the algorithm is evaluated by two-dimensional alignment of sections from mouse brains located in the olfactory bulbs. The registration algorithm was guided by manually delineated contours of a subset of brain structures and validated based on another subset of brain structures. The wavelet alignment algorithm produced a twofold to fivefold improvement in accuracy over an affine (linear) alignment algorithm. 相似文献
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Ti-6Al-4V alloys consisting of α-Ti grains and intergranular β-Ti islands were nitrided at 850°C for 1 to 12 h under a nitrogen pressure of 1 Pa. With increasing nitriding time, the Ti-N compound layer became thicker, and the α-Ti diffusion zone containing dissolved nitrogen became wider. In the Ti-N compound layer, the initially formed Ti2N became TiN as the nitriding progressed. The nitride layers were oxidized to rutile-TiO2 after oxidation at 700°C for 10 h in air. 相似文献