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基于优化随机森林回归模型的土壤盐渍化反演

地球信息科学学报 2021年第9期23卷 1662-1674页

作者：杨练兵陈春波郑宏伟罗格平尚白军 olaf hellwich 中国科学院新疆生态与地理研究所荒漠与绿洲生态国家重点实验室乌鲁木齐830011 新疆维吾尔自治区遥感与地理信息系统应用重点实验室乌鲁木齐830011 中国科学院大学北京100049 中国科学院中亚生态与环境研究中心乌鲁木齐830011 德国柏林工业大学计算机视觉和遥感研究所柏林10623

当前应用于土壤盐分含量(Soil Salinity Content,SSC)反演的随机森林回归(Random Forests Regression,RFR)较少关注对模型精度影响较大的反演参数子集和模型参数的同步优化。本研究选择渭-库绿洲和奇台绿洲为实验区,基于Landsat-5 TM、S... 详细信息

当前应用于土壤盐分含量(Soil Salinity Content,SSC)反演的随机森林回归(Random Forests Regression,RFR)较少关注对模型精度影响较大的反演参数子集和模型参数的同步优化。本研究选择渭-库绿洲和奇台绿洲为实验区,基于Landsat-5 TM、SRTM、MOD11A2.006遥感数据构建反演参数。首先,利用弹性网络(Elastic Net,EN)筛选出反演参数子集,然后利用遗传算法(Genetic Algorithm,GA)和贝叶斯优化算法(Bayesian Optimization Algorithm,BOA)分别优化随机森林回归(Random Forests Regression,RFR)参数,建立反演参数子集和模型参数分步优化的RFR模型(EN-GA-RFR、EN-BOA-RFR)。建立利用GA和BOA分别同步优化反演参数子集和模型参数的RFR模型(GA-RFR、BOA-RFR)。在每个实验区,对比EN-GARFR、EN-BOA-RFR、GA-RFR、BOA-RFR的预测精度。最后分析每个实验区各类盐渍土的空间分布,并对2个实验区的反演参数进行对比分析。结果表明:每个实验区模型预测精度由高到低的排序均为BOA-RFR>GA-RFR>EN-BOA-RFR=EN-GARFR,整体上BOA的优化性能均好于GA;渭-库绿洲和奇台绿洲面积占比最大的盐渍土类型分别为盐渍土和中度盐渍土;反演参数对SSC的表征能力存在空间分异性。

关键词：土壤盐分含量同步优化随机森林回归贝叶斯优化算法遗传算法弹性网络反演参数子集模型参数

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水管理对干旱区盐渍化与土地退化中和的影响

Science Bulletin 2023年第24期68卷 3240-3251,M0006页

作者：施海洋罗格平 Edwin H.Sutanudjaja olaf hellwich 陈曦丁建丽吴世新何秀凤陈春波 Friday U.Ochege 王渊刚凌青艾里西尔·库尔班 Philippe De Maeyer Tim Van de Voorde State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Research Centre for Ecology and Environment of Central Asia Chinese Academy of SciencesUrumqi 830011China Department of Geography Ghent UniversityGhent 9000Belgium College of Resources and Environment Sciences Xinjiang UniversityUrumqi 830046China Department of Physical Geography Utrecht UniversityUtrecht 3584Netherlands Department of Computer Vision&Remote Sensing Technical University of BerlinBerlin 10587Germany Sino-Belgian Joint Laboratory of Geo-Information Ghent 9000Belgium School of Earth Sciences and Engineering Hohai UniversityNanjing 211100China Department of Geography and Environmental Management University of Port HarcourtPort Harcourt 500004Nigeria

通过优化灌溉和水资源管理以减少耕地土壤盐渍化对实现土地退化中和至关重要.各种灌溉和水资源管理措施对流域尺度盐渍化的缓解作用的有效性和可持续性尚不明确.本研究利用遥感技术估算了1984-2021年干旱区耕地的表层土壤盐度.然后,利... 详细信息

通过优化灌溉和水资源管理以减少耕地土壤盐渍化对实现土地退化中和至关重要.各种灌溉和水资源管理措施对流域尺度盐渍化的缓解作用的有效性和可持续性尚不明确.本研究利用遥感技术估算了1984-2021年干旱区耕地的表层土壤盐度.然后,利用贝叶斯网络分析比较了十个大型干旱区流域(尼罗河、底格里斯-幼发拉底河、印度河、塔里木河、阿姆河、伊犁河、锡尔河、准格尔盆地、科罗拉多河和圣华金河流域)的土壤表层盐度对水资源管理(如各种灌溉和排水方式)的时空响应.在开发水平较高的流域,管理者采用滴灌和地下水灌溉,通过降低地下水水位有效地控制了土壤盐度.对于仍采用传统漫灌的流域,经济发展和政策支持对于建立“改善灌溉系统——降低盐度——增加农业收入”的良性循环至关重要.这也是实现土地退化中和目标的关键.

关键词： Soil salinization Land degradation neutralization Irrigation Water management Bayesian networks Drylands

Influence of rotating wakes on separation in turbine exhaust diffusers

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Journal of Thermal Science 2008年第1期17卷 42-49页

作者： olaf Sieker Joerg R.Seume Department of Turbomachinery and Fluid Dynamics Leibniz University HannoverAppelstr.9DE-30167 HannoverGermany Dipl.-Ing. Department of Turbomachinery and Fluid Dynamics Leibniz University HannoverAppelstr.9DE-30167 HannoverGermany

Highly efficient turbine exhaust diffuser cannot be designed without taking into account the unsteady interactions with the last rotating row of the turbine. Former investigations described in the literature show a very high potential compared to that of other parts of turbomachines for improving the diffuser. A scale model of a typical gas turbine exhaust diffuser is investigated experimentally. To investigate the influence of rotating wakes, measurements without a spoke wheel as well as measurements with a variable-speed rotating cylindrical spoke wheel with 2 mm- or 10 mm-spokes simulating turbine rotor wakes were made. Miniaturized 3-hole pneumatic probes as well as a 2D-Laser-Doppler-Velocimeter （LDV） were used to investigate velocity profiles. 122 static pressure tapings were used to measure several axial and circumferential static pressure distributions. Without a spoke-wheel the annular diffuser separates at the shroud for all swirl configurations. For the measurements with the 2 mm spoke wheel, the separating diffuser was unstable while keeping the test rig operating parameters constant. For a non-rotating 10 mm spoke wheel and at rotational speeds less than 1,000 rpm, the annular diffuser separated at the shroud. Increasing the rotational speed of the 10mm spoke wheel, flow did not separate at the shroud and much higher pressure recovery than without spoke wheel has achieved.

关键词： turbine exhaust diffuser rotating wakes separation LDV

Impacts of prenatal nutrition on animal production and performance： a focus on growth and metabolic and endocrine function in sheep

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Journal of Animal Science and Biotechnology 2018年第1期9卷 10-23页

作者： Prabhat Khanal Mette olaf Nielsen Department of Veterinary and Animal Sciences Faculty of Health and Medical SciencesUniversity of Copenhagen Gronnegardsvey 31st floorDK-1870 Frederiksberg CDenmark Department of Nutrition Faculty of MedicineTransgenic Animal and Lipid StorageNorwegian Transgenic Centre(NTS)University of OsloOsloNotway

The concept of foetal programming（FP） originated from human epidemiological studies, where foetal life nutrition was linked to health and disease status later in life. Since the proposal of this phenomenon, it has been evaluated in various animal models to gain further insights into the mechanisms underlying the foetal origins of health and disease in humans. In FP research, the sheep has been quite extensively used as a model for humans. In this paper we will review findings mainly from our Copenhagen sheep model, on the implications of late gestation malnutrition for growth, development, and metabolic and endocrine functions later in life, and discuss how these implications may depend on the diet fed to the animal in early postnatal life. Our results have indicated that negative implications of foetal malnutrition, both as a result of overnutrition and, particularly, late gestation undernutrition, can impair a wide range of endocrine functions regulating growth and presumably also reproductive traits. These implications are not readily observable early in postnatal life, but are increasingly manifested as the animal approaches adulthood. No intervention or cure is known that can reverse this programming in postnatal life. Our findings suggest that close to normal growth and slaughter results can be obtained at least until puberty in animals which have undergone adverse programming in foetal life, but manifestation of programming effects becomes increasingly evident in adult *** to the risk of transfer of the adverse programming effects to future generations, it is therefore recommended that animals that are suspected to have undergone adverse FP are not used for reproduction. Unfortunately, no reliable biomarkers have as yet been identified that allow accurate identification of adversely programmed offspring at birth,except for very low or high birth weights, and, in pigs, characteristic changes in head shape（dolphin head）. Future efforts should be therefo

关键词： Adipose tissue Endocrine function Foetal programming Metabolic function Sheep

Effect of Different Calcination Temperatures and Post Annealing on the Properties of Acetic Acid Based Sol-Gel (Na_(0.5)K_(0.5))NbO_3(NKN) Thin Films

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Journal of Materials Science & Technology 2013年第2期29卷 142-148页

作者： Sebastian Wiegand Stefan Flege olaf Baake Wolfgang Ensinger Materials Analysis Group Department of Materials and Geosciences Technische Universitt Darmstadt Petersenstrasse 23 64287 Darmstadt Germany

（Na0.5K0.5）NbO3 （NKN） lead free thin films were synthesized by means of an acetic acid based sol-gel process on Pt/Ti/SiO2/Si substrates. Na-acetate, K-acetate and Nb-pentaethoxide were used as metal precursors and acetic acid as the solvent. The effect of different calcination temperatures on the properties of the NKN films was investigated by X-ray diffraction, scanning electron microscopy, leakage current and hysteresis measurements. Low calcination temperatures led to low currents at high electric fields whereas high calcination temperatures led to low currents at low electric fields. Based on these findings calcination at low temperature was combined with a post annealing treatment. Low leakage currents of 4×10^-4 A/cm2 at 150 kV/cm and 2Pr and 2Ec values of 28 μC/cm2 and 150 kV/cm, respectively, could be obtained. All films were single phase NKN with random crystal orientations and no crack or pore formation was visible on the surface.

关键词： Sol-gel process (Na0.5K0.5)NbO3 Thin film Perovskite Lead-free Piezo material

Synthesis and Characterization of(Na_(0.5)K_(0.5))NbO_3(NKN) Thin Films Formed by a Diol-based Sol-gel Process

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Journal of Materials Science & Technology 2012年第6期28卷 500-505页

作者： Sebastian Wiegand Stefan Flege olaf Baake Wolfgang Ensinger Technische Universitt Darmstadt Department of Materials and GeosciencesMaterials Analysis GroupPetersenstrasse 2364287 DarmstadtGermany

Lead-free （***0.5）Nb03 （NKN） thin films were fabricated by spin coating on Pt/Ti/SiO2/Si substrates by a diol-based sol-gel process. Na-acetate, K-acetate, Nb-pentaethoxide and 1,3 propanediol were used to prepare the NKN precursor solution. Thermal analysis showed two characteristic temperatures of 360 and 600℃. Based on these temperatures, a heat treatment program with pyrolysis at 360℃ and calcination at 600℃ after every layer was used. To avoid inhomogeneities and secondary phases, an excess of sodium and potassium was necessary. To evaluate the proper excess amount of sodium and potassium secondary ion mass spectrometry （SIMS） lateral element maps and X-ray diffraction （XRD） patterns were recorded. An excess amount of 20% led to homogeneous distribution of the elements and to single phase perovskite NKN films with random crystal orientation. Scanning electron microscopy （SEMI images showed a pore free surface with 100 nm grains. The leakage current measurements showed a current of lx10-3 A/cm2 at 150 kV/cm.

关键词： Sol-gel process (Nao.sK0.5)NbO3 Thin film Perovskite Lead-free Piezo material

Fatalities caused by novel opioids:a review

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Forensic Sciences Research 2019年第2期4卷 95-110页

作者： olaf H.Drummer Department of Forensic Medicine School of Public Health and Preventive MedicineFaculty of MedicineNursing and Health SciencesMonash UniversitySouthbankVictoriaAustralia

Drugs related to morphine represent not only large range of important therapeutic applications for the relief of moderate to severe pain but also give rise to a relatively large series of novel opioids that mimic the action of this naturally occurring *** of these are based on fentanyl structures that are much more potent,and dangerous,than fentanyl *** publication reviews reports of fatalities attributed to 15 novel opioids with the view to assessing mortality associated with their misuse as well as reviewing published analytical procedures that would be able to detect these and other novel *** drugs include reports of deaths to acetylfentanyl,acrylfentanyl,butr(yl)fentanyl,carfentanil,2-and 4-fluorofentanyls,4-fluorobutyrfentanyl,4-fluoroisobutyrfentanyl,furanylfentanyl,a-and 3-methylfentanyls,4-methoxyfentanyl,ocfentanil,as well as AH-7921,U-47700 and *** of these cases reporting a drug-caused death involved other drugs in addition to the *** obvious minimum fatal concentration was discerned for any of the opioids for which details were provided,however,the more potent members required detection limits well under 1 ng/mL and often even well below 0.1 ng/mL requiring use of the most sensitive mass spectral detection procedures,particularly when screening specimens using a non-targeted *** other novel opioids have been reported in admissions to hospitals include 4-chloroisobutryfentanyl,cyclopentylfentanyl and tetrahydrofuranfentanyl,all of which are likely to have the potential to cause *** is also likely that other analogues will appear with time.

关键词： Forensic science forensic toxicology opioids poisoning illicit drugs novel psychoactive drugs fentanyl derivatives mass spectrometry

Numerical Investigation of the Temperature and Flow Fields in a Solar Chimney Power Plant

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Fluid Dynamics & Materials Processing 2023年第4期19卷 1055-1066页

作者： Roudouane Laouar olaf Wünsch Laboratory of Environment Larbi Tebessi UniversityTebessaAlgeria Department of Fluid Dynamics University of KasselKasselGermany

In this work,a parametric two-dimensional computational fluid dynamics(CFD)analysis of a solar chimney power plant(a prototype located in Manzanares,Spain)is presented to illustrate the effects of the solar radiation mode in the collector on the plant *** simulations rely on a mathematical model that includes solar radiation within the collector;energy storage;air flow and heat transfer,and a *** is based on the Navier-Stokes equation for turbulent flow formulated according to the standard k-ε***,the Boussinesq approach is used to account for the fluid density *** solar radiation modes in the collector are compared and *** obtained results are also compared with available experimental *** is shown that the radiation model is essential to avoid overestimation of the energy absorbed by the plant and that results based on a two-dimensional model can resemble closely those produced by three-dimensional models.

关键词： Solar radiation model two-dimensional axisymmetric model Boussinesq model greenhouse effect

Optical coatings:trends and challenges

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光学精密工程 2005年第4期13卷 389-396页

作者： Norbert Kaiser Torsten Feigl olaf Stenzel Ulrike Schulz Fraunhofer Institut für Angewandte Optik und Feinmechanik Albert-Einstein-Str. 7D-07745 Jena GermanyFraunhofer Institut für Angewandte Optik und Feinmechanik Albert-Einstein-Str. 7D-07745 Jena GermanyFraunhofer Institut für Angewandte Optik und Feinmechanik Albert-Einstein-Str. 7D-07745 Jena GermanyFraunhofer Institut für Angewandte Optik und Feinmechanik Albert-Einstein-Str. 7D-07745 Jena Germany

New applications in optoelectronics, photonics, telecommunication, displays, optical data processing, biomedicine, sensors, energy control, automobile, aerospace, and architecture stimulation are important developments in physics and technology of optical coatings. This paper will focus on the latest advances in the areas of new optical film systems and devices, new optical coating materials and film fabrication techniques, process control and monitoring, and different advanced applications. Particularly, focus is on optical films that combine optical design with microstructural features tailored on the nanometer and micrometer scales. Evaluation of film stability and integrity in harsh industrial environments and their compatibility with organic polymers are important as well.

关键词：光学涂覆技术光电子技术光学仪器光学材料