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Comparison of estimators of variance for forest inventories with systematic sampling-results from artificial populations

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Forest Ecosystems 2020年第2期7卷 215-233页

作者： steen Magnussen Ronald EMcRoberts Johannes Breidenbach Thomas Nord-Larsen göran ståhl Lutz Fehrmann Sebastian Schnell 506 West Burnside Road VictoriaBC V8Z 1M5Canada Raspberry Ridge Analytics 15111 Elmcrest Avenue NorthHugoMN 55038USA Norwegian Institute of Bioeconomy Research Høgskolevegen 81431ÅsNorway Department of geosciences and Natural Resource Management University of CopenhagenRolighedsvej 23DK-1958 Frederiksberg CDenmark Department of Forest Resource Management Swedish University of Agricultural SciencesUmeåSweden Forest Inventory and Remote Sensing Faculty of Forest SciencesUniversity of GöttingenBüsgenweg 5D37077GöttingenGermany Alfred-Möller-straße 1 Haus 41-4216225 EberswaldeGermany.

Background:Large area forest inventories often use regular grids(with a single random start)of sample locations to ensure a uniform sampling intensity across the space of the surveyed populations.A design-unbiased estimator of variance does not exist for this ***,a quasi-default estimator applicable to simple random sampling(SRS)is used,even if it carries with it the likely risk of overestimating the variance by a practically important *** better exploit the precision of systematic sampling we assess the performance of five estimators of variance,including the quasi *** this study,simulated systematic sampling was applied to artificial populations with contrasting covariance structures and with or without linear *** compared the results obtained with the SRS,Matern’s,successive difference replication,Ripley’s,and D’Orazio’s variance ***:The variances obtained with the four alternatives to the SRS estimator of variance were strongly correlated,and in all study settings consistently closer to the target design variance than the estimator for *** latter always produced the greatest *** populations with a near zero spatial autocorrelation,all estimators,performed equally,and delivered estimates close to the actual design ***:Without a linear trend,the SDR and DOR estimators were best with variance estimates more narrowly distributed around the benchmark;yet in terms of the least average absolute deviation,Matern’s estimator held a narrow *** a strong or moderate linear trend,Matern’s estimator is *** large populations,and a low sampling intensity,the performance of the investigated estimators becomes more similar.

关键词： Spatial autocorrelation Linear trend Model based Design biased Matern variance Successive difference replication variance geary contiguity coefficient random site effects

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Cross-classes domain inference with network sampling for natural resource inventory

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Forest Ecosystems 2022年第3期9卷 311-322页

作者： Zhengyang Hou Ronald E.McRoberts Chunyu Zhang göran ståhl Xiuhai Zhao Xuejun Wang Bo Li Qing Xu The Key Laboratory for Silviculture and Conservation of Ministry of Education Beijing Forestry UniversityBeijingChina Department of Forest Resources University of MinnesotaSaint PaulMNUnited States Department of Forest Resource Management Swedish University of Agricultural SciencesUmeåSweden Office of the National Forestry and grassland Administrations Forest Resources Supervision Commissioner in Beijing BeijingChina Department of statistics University of Illinois at Urbana-ChampaignChampaignILUnited States Key Laboratory on the Science and Technology of Bamboo and Rattan International Centre for Bamboo and RattanBeijingChina

There are two distinct types of domains,design-and cross-classes domains,with the former extensively studied under the topic of small-area *** natural resource inventory,however,most classes listed in the condition tables of national inventory programs are characterized as cross-classes domains,such as vegetation type,productivity class,and age *** date,challenges remain active for inventorying cross-classes domains because these domains are usually of unknown sampling frame and spatial distribution with the result that inference relies on population-level as opposed to domain-level *** challenges are noteworthy:(1)efficient sampling strategies are difficult to develop because of little priori information about the target domain;(2)domain inference relies on a sample designed for the population,so within-domain sample sizes could be too small to support a precise estimation;and(3)increasing sample size for the population does not ensure an increase to the domain,so actual sample size for a target domain remains highly uncertain,particularly for small *** this paper,we introduce a design-based generalized systematic adaptive cluster sampling(gSACS)for inventorying cross-classes ***-unbiased Hansen-Hurwitz and Horvitz-Thompson estimators are derived for domain totals and compared within gSACS and with systematic sampling(SYS).Comprehensive Monte Carlo simulations show that(1)gSACS Hansen-Hurwitz and Horvitz-Thompson estimators are unbiased and equally efficient,whereas thelatter outperforms the former for supporting a sample of size one;(2)SYS is a special case of gSACS while the latter outperforms the former in terms of increased efficiency and reduced intensity;(3)gSACS Horvitz-Thompson variance estimator is design-unbiased for a single SYS sample;and(4)rules-ofthumb summarized with respect to sampling design and spatial effect improve *** inventorying a mini domain is analogous to inventorying a rare vari

关键词： Cross-classes domain estimation Design-based inference Network sampling generalized systematic adaptive cluster sampling Forest inventory

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Mapping aboveground biomass and its prediction uncertainty using LiDAR and field data, accounting for tree-level allometric and LiDAR model errors

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Forest Ecosystems 2020年第3期7卷 562-578页

作者： Svetlana Saarela AndréWästlund Emma Holmström Alex Appiah Mensah Sören Holm Mats Nilsson Jonas Fridman göran ståhl Faculty of Forest Sciences Swedish University of Agricultural SciencesSLU Skogsmarksgränd 17UmeåSE-90183Sweden

Background: The increasing availability of remotely sensed data has recently challenged the traditional way of performing forest inventories, and induced an interest in model-based inference. Like traditional design-based inference, model-based inference allows for regional estimates of totals and means, but in addition for wall-to-wall mapping of forest characteristics. Recently Light Detection and ranging(LiDAR)-based maps of forest attributes have been developed in many countries and been well received by users due to their accurate spatial representation of forest resources. However, the correspondence between such mapping and model-based inference is seldom appreciated. In this study we applied hierarchical model-based inference to produce aboveground biomass maps as well as maps of the corresponding prediction uncertainties with the same spatial resolution. Further, an estimator of mean biomass at regional level, and its uncertainty, was developed to demonstrate how mapping and regional level assessment can be combined within the framework of model-based ***: Through a new version of hierarchical model-based estimation, allowing models to be nonlinear, we accounted for uncertainties in both the individual tree-level biomass models and the models linking plot level biomass predictions with LiDAR metrics. In a 5005 km2 large study area in south-central Sweden the predicted aboveground biomass at the level of 18 m×18 m map units was found to range between 9 and 447 Mg·ha^-1. The corresponding root mean square errors ranged between 10 and 162 Mg·ha^-1. For the entire study region, the mean aboveground biomass was 55 Mg·ha^-1 and the corresponding relative root mean square error 8%. At this level 75%of the mean square error was due to the uncertainty associated with tree-level ***: Through the proposed method it is possible to link mapping and estimation within the framework of model-based inference. Uncertainties in both tree-level bio

关键词： Aboveground biomass assessment Forest mapping gauss-Newton Regression Hierarchical Model-Based inference LiDAR maps National Forest Inventory Uncertainty estimation Uncertainty map

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Why ecosystem characteristics predicted from remotely sensed data are unbiased and biased at the same time-and how this affects applications

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Forest Ecosystems 2024年第1期11卷 24-31页

作者： goran ståhl Terje gobakken Svetlana Saarela Henrik J.Persson Magnus Ekstrom Sean P.Healey Zhiqiang Yang Johan Holmgren Eva Lindberg Kenneth Nystrom Emanuele Papucci Patrik Ulvdal Hans OleØrka Erik Næsset Zhengyang Hou Håkan Olsson Ronald E.McRoberts Department of Forest Resource Management Swedish University of Agricultural Sciences90183UmeåSweden Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life SciencesÅsNorway USDA Forest Service Rocky Mountain Research StationOgdenUTUSA The Key Laboratory for Silviculture and Conservation of Ministry of Education Beijing Forestry UniversityBeijing100083China Department of Forest Resources University of MinnesotaSt.PaulMNUSA

Remotely sensed data are frequently used for predicting and mapping ecosystem characteristics,and spatially explicit wall-to-wall information is sometimes proposed as the best possible source of information for ***,wall-to-wall information typically relies on model-based prediction,and several features of model-based prediction should be understood before extensively relying on this type of *** such feature is that model-based predictors can be considered both unbiased and biased at the same time,which has important implications in several areas of *** this discussion paper,we first describe the conventional model-unbiasedness paradigm that underpins most prediction techniques using remotely sensed(or other)auxiliary *** this point of view,model-based predictors are typically ***,we show that for specific domains,identified based on their true values,the same model-based predictors can be considered biased,and sometimes severely *** suggest distinguishing between conventional model-bias,defined in the statistical literature as the difference between the expected value of a predictor and the expected value of the quantity being predicted,and design-bias of model-based estimators,defined as the difference between the expected value of a model-based estimator and the true value of the quantity being *** show that model-based estimators(or predictors)are typically design-biased,and that there is a trend in the design-bias from overestimating small true values to underestimating large true ***,we give examples of applications where this is important to acknowledge and to potentially make adjustments to correct for the design-bias *** argue that relying entirely on conventional model-unbiasedness may lead to mistakes in several areas of application that use predictions from remotely sensed data.

关键词： Bias Model-based inference Design-based inference

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Design strategies and insights of flexible infrared optoelectronic sensors

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Journal of Semiconductors 2025年第1期46卷 21-56页

作者： Yegang Liang Wenhao ran Dan Kuang Zhuoran Wang School of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijing 100081China

Infrared optoelectronic sensing is the core of many critical applications such as night vision,health and medication,military,space exploration,*** including mechanical flexibility as a new dimension enables novel features of adaptability and conformability,promising for developing next-generation optoelectronic sensory applications toward reduced size,weight,price,power consumption,and enhanced performance(SWaP^(3)).However,in this emerging research frontier,challenges persist in simultaneously achieving high infrared response and good mechanical deformability in devices and integrated ***,we perform a comprehensive review of the design strategies and insights of flexible infrared optoelectronic sensors,including the fundamentals of infrared photodetectors,selection of materials and device architectures,fabrication techniques and design strategies,and the discussion of architectural and functional integration towards applications in wearable optoelectronics and advanced image ***,this article offers insights into future directions to practically realize the ultra-high performance and smart sensors enabled by infrared-sensitive materials,covering challenges in materials development and device micro-/*** for scaling these techniques across fabrication,performance,and integration are presented,alongside perspectives on potential applications in medication and health,biomimetic vision,and neuromorphic sensory systems,etc.

关键词： flexible infrared sensor infrared-sensitive materials device architectures fabrication techniques design strategies

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Micro-strain regulation strategy to stabilize perovskite lattice based on the categories and impact of strain on perovskite solar cells

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Journal of Energy Chemistry 2025年第1期100卷 578-604页

作者： Caixia Li Wenwu Liu Shiji Da Lingbin Kong Fen ran state Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou 730050GansuChina School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050GansuChina

Photovoltaic metal halide perovskite solar cells(PSCs) convert light to electricity more efficiently than crystalline silicon cells, and the cost of materials used to make them is lower than that of silicon *** efficiency is not a core issue affecting the application of perovskite solar cells in special *** present, stability is the major technical encounters that hinders its further commercial development. Microstrain in PSCs is currently a significant factor responsible for the device's instability. strain-induced ion migration is widely believed to accelerate perovskite degradation even when external stimuli are ***, it is imperative to study strain to enhance the stability of PSCs. This paper reviews recent developments to understand strain's origin and effect mechanisms on performance of PSCs, including ion migration,failure behavior, defect formation, and its effect on photoelectric properties, stability, and ***, several well-known strain management strategies are systematically introduced based on the strain effect mechanism and strain engineering on the film, providing more clues for further preparation with increased stability. The manipulation of external physical strain applied from films to entire devices has been extensively studied. Furthermore, recommendations for future research directions and chemical approaches have been provided. It is emphasized that strain engineering plays a crucial role in improving the efficiency and longevity of PSCs. Tensile strain causes rapid degradation, while moderate compressive strain and external strain control could improve properties and stability. Efforts should focus on controlling compressive strain to mitigate residual tensile strain and introducing it in a controlled manner. Future research endeavors may focus on exploring these pathways to improve the efficiency and lifespan of PSCs.

关键词： Halide perovskite solar cells strain origins strain effects strain management

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Systematic experimental investigation on pressure build-up characteristics of water-jet injection into a molten LBE pool

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Nuclear Science and Techniques 2025年第1期36卷 161-174页

作者： Hao-ran Huang Zi-Jian Deng Song-Bai Cheng Jia-Yue Chen Sino‑French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China College of Nuclear Science and Technology Harbin Engineering UniversityHarbin 150001China

In the scenario of a steam generator tube rupture accident in a lead-cooled fast reactor,secondary circuit subcooled water under high pressure is injected into an ordinary-pressure primary vessel,where a molten lead-based alloy(typically pure lead or lead-bismuth eutectic(LBE))is used as the *** clarify the pressure build-up characteristics under water-jet injection,this study conducted several experiments by injecting pressurized water into a molten LBE pool at Sun Yat-sen *** obtain a further understanding,several new experimental parameters were adopted,including the melt temperature,water subcooling,injection pressure,injection duration,and nozzle *** detailed analyses,it was found that the pressure and temperature during the water-melt interaction exhibited a consistent variation trend with our previous water-droplet injection mode LBE ***,the existence of a steam explosion was confirmed,which typically results in a much stronger pressure *** the non-explosion cases,increasing the injection pressure,melt-pool temperature,nozzle diameter,and water subcooling promoted pressure build-up in the melt ***,a limited enhancement effect was observed when increasing the injection duration,which may be owing to the continually rising pressure in the interaction vessel or the isolation effect of the generated steam *** of whether a steam explosion occurred,the calculated mechanical and kinetic energy conversion efficiencies of the melt were relatively small(not exceeding 4.1%and 0.7%,respectively).Moreover,the range of the conversion efficiency was similar to that of previous water-droplet experiments,although the upper limit of the jet mode was slightly lower.

关键词： Lead-cooled fast reactor steam generator tube rupture accident Pressure build-up characteristics Experimental study Pressure water-jet injection

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High-temperature oxidation behavior and degradation mechanism of chromium-coated zirconium alloy cladding: a review

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Tungsten 2025年第1期7卷 50-70页

作者： Yi Li Bei-Qi Wang Xin-Yin Zhang Shi-Jie Wang Cong-Yi Li Hui-Long Yang ran-ran Su Tong Liu School of Mechanical Engineering Shanghai Jiao Tong University College and graduate School of Arts and Sciences University of Virginia global Institute of Future Technology Shanghai Jiao Tong University

Accident-tolerant fuels(ATF) have been extensively studied to reduce the production rate and total amount of heat and hydrogen generated from high-temperature steam oxidation during severe ***-coated zirconium alloy cladding has become one of the most promising candidates for ATF because of its excellent corrosion and oxidation *** paper provides a comprehensive overview of the research progress on oxidation behaviors and degradation mechanisms in chromium-coated zirconium alloy cladding under high-temperature *** techniques to strengthen the oxidation resistance are highlighted and ***,challenges and opportunities for various future directions are addressed.

关键词： Accident-tolerant fuel Chromium coating Degradation mechanism High-temperature oxidation behavior Zirconium alloy cladding

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strong resistance toβ-cyfluthrin in a strain of the beetle Alphitobius diaperinus:a de novo transcriptome analysis

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Insect Science 2025年第1期32卷 209-226页

作者： gwenola gouesbet David Renault stéphane APDerocles HervéColinet CNRS ECOBIO(EcosystèmesBiodiversitéÉvolution)—UMR 6553University of RennesRennesFrance Institut Universitaire de France 1 rue DescartesCEDEX 05ParisFrance

The lesser mealworm,Alphitobius diaperinus,is an invasive tenebrionid beetle and a vector of *** to the emergence of insecticide resistance and consequent outbreaks that generate significant phytosanitary and energy costs for poultry farmers,it has become a major insect pest *** better understand the molecular mechanisms behind this resistance,we studied a strain of *** from a poultry house in Brittany that was found to be highly resistant to theβ-*** strain survivedβ-cyfluthrin exposures corresponding to more than 100 times the recommended *** used a comparative de novo RNA-Seq approach to explore genes expression in resistant versus sensitive *** de novo transcriptomic analyses showed that responses toβ-cyfluthrin likely involved a whole set of resistance *** related to detoxification,metabolic resistance,cuticular hydrocarbon biosynthesis and proteolysis were found to be constitutively overexpressed in the resistant compared to the sensitive ***-up enzymatic assays confirmed that the resistant strain exhibited high basal activities for detoxification enzymes such as cytochrome P450 monooxygenase and *** in-depth analysis of differentially expressed genes suggests the involvement of complex regulation of signaling *** knowledge of these resistance mechanisms is essential for the establishment of effective pest control.

关键词： Alphitobius diaperinus de novo transcriptome insecticide resistance P450 xenobiotic metabolism

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structural designs and mechanism insights into electrocatalytic oxidation of 5-hydroxymethylfurfural

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Journal of Energy Chemistry 2025年第1期100卷 792-814页

作者： Jing Lei Huijie Zhang Jian Yang Jia ran Jiqiang Ning Haiyan Wang Yong Hu Key Laboratory of the Ministry of Education for Advanced Catalysis Materials Department of ChemistryZhejiang Normal UniversityJinhua 321004ZhejiangChina Jinhua Advanced Research Institute Jinhua 321019ZhejiangChina Department of Optical Science and Engineering Fudan UniversityShanghai 200438China College of Chemistry and Materials Engineering Zhejiang A&F UniversityHangzhou 311300ZhejiangChina

Biomass conversion offers an efficient approach to alleviate the energy and environmental *** oxidation of 5-hydroxymethylfurfural(HMF)has attracted tremendous attention in the latest few years for the mild synthesis conditions and high conversion efficiency to obtain 2,5-furan dicarboxylic acid(FDCA),but there still remain problems such as limited yield,short cycle life,and ambiguous reaction *** many reviews highlighting a variety of electrocatalysts for electrochemical oxidation of HMF,a detailed discussion of the structural modulation of catalyst and the underlying catalytic mechanism is still *** herein provide a comprehensive summary of the recent development of electrochemical oxidation of HMF to FDCA,particularly focusing on the mechanism studies as well as the advanced strategies developed to regulate the structure and optimize the performance of the electrocatalysts,including heterointerface construction,defect engineering,single-atom engineering,and in situ *** characterization techniques and theoretical calculation methods for mechanism and active site studies are elaborated,and challenges and future directions of electrochemical oxidation of HMF are also *** review will provide guidance for designing advanced catalysts and deepening the understanding of the reaction mechanism beneath electrochemical oxidation of HMF to FDCA.

关键词： Electrochemical oxidation of 5- hydroxymethylfurfural 2,5-Furan dicarboxylic acid structural design Mechanism Electrocatalysts

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