检索结果-南通市图书馆

Natural forests exhibit higher organic carbon concentrations and recalcitrant carbon proportions in soil than plantations:a global data synthesis

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2024年第5期35卷 131-141页

作者： Xiuqing nie Hui Wang Jian Wang Shirong Liu Ecology and Nature Conservation Institute Chinese Academy of ForestryKey Laboratory of Forest Ecology and Environment of National Forestry and Grassland AdministrationNo.2 DongxiaofuHaidian DistrictBeijing 100091People’s Republic of China

Different chemical compositions of soil organic carbon(SOC)affect its persistence and whether it signifi-cantly differs between natural forests and plantations remains *** synthesizing 234 observations of SOC chemical compositions,we evaluated global patterns of concentra-tion,individual chemical composition(alkyl C,O-alkyl C,aromatic C,and carbonyl C),and their distribution *** results indicate a notably higher SOC,a markedly larger proportion of recalcitrant alkyl C,and lower easily decomposed carbonyl C proportion in natural ***-ever,SOC chemical compositions were appreciably more evenly distributed in *** on the assumed con-ceptual index of SOC chemical composition evenness,we deduced that,compared to natural forests,plantations may have higher possible resistance to SOC decomposition under *** tropical regions,SOC levels,recalcitrant SOC chemical composition,and their distributed evenness were significantly higher in natural forests,indicating that SOC has higher chemical stability and possible resistance to *** factors had minor effects on alkyl C in forests globally,while they notably affected SOC chemi-cal composition in tropical *** could contribute to the differences in chemical compositions and their distrib-uted evenness between plantations and natural stands.

关键词： Global data synthesis Natural forest Plantations Soil organic carbon Soil organic carbon chemical composition

Improving the underwater navigation performance of an IMU with acoustic long baseline calibration

在线全文

学校读者我要写书评

暂无评论

Satellite Navigation 2024年第1期5卷 224-239页

作者： Paipai Wu Wenfeng nie Yangfan Liu Tianhe Xu Shandong Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment Institute of Space SciencesShandong UniversityWeihai264209ShandongChina Research Group of Astronomy and Geomatics(gAGE) Universitat Politecnica de Catalunya(UPC)BarcelonaSpain

Underwater acoustic Long-Baseline System(LBL)is an important technique for submarine positioning and ***,the high cost of the seafloor equipment and complex construction of a seafloor network restrict the distribution of the LBL within a small area,making an underwater vehicle difficult for long-distance and high-precision acoustic-based or inertial-based *** therefore propose an acoustic LBL-based Inertial Measurement Unit(IMU)calibration *** the underwater vehicle can receive the acoustic signal from a seafloor beacon,the IMU is precisely calibrated to reduce the cumulative error of Strapdown Inertial Navigation System(SINS).In this way,the IMU is expected to maintain a certain degree of accuracy by relying solely on SINS when the vehicle reaches out the range of the LBL network and cannot receive the acoustic *** present the acoustic LBL-based IMU online calibration model and analyze the factors that affect the accuracy of IMU *** results fulfill the expectation that the gyroscope bias and accelerometer bias are the main error sources that affect the divergence of SINS position errors,and the track line of the underwater vehicle directly affects the accuracy of the calibration *** addition,we deduce that an optimal calibration trajectory needs to consider the effects of the three-dimensional observability and position dilution of *** the experiment,we compare the effects of seven calibration trajectories:straight and diamond-shaped with and without the change of depth,and three sets of curves with the change of depth:circular,S-shaped,and *** them,we find that the figure-eight is the optimal trajectory for acoustic LBL-based IMU online *** take the maintenance period during which the accumulated SINS Three Dimensional(3D)position errors are below 1 km to evaluate the calibration *** filed experimental results show that for the Micro-electromechanical System

关键词： Acoustic LBL Online IMU calibration SINS Relay reference network

Learning the optimal power flow:Environment design matters

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy and AI 2024年第3期17卷 432-443页

作者： Thomas Wolgast Astrid nieße Carl von Ossietzky Universität Oldenburg Department of Computing ScienceDigitalized Energy SystemsAmmerländer Heerstraße 114-118Oldenburg26129Germany

To solve the optimal power flow(OPF)problem,reinforcement learning(RL)emerges as a promising new ***,the RL-OPF literature is strongly divided regarding the exact formulation of the OPF problem as an RL *** this work,we collect and implement diverse environment design decisions from the literature regarding training data,observation space,episode definition,and reward function *** an experimental analysis,we show the significant impact of these environment design options on RL-OPF training ***,we derive some first recommendations regarding the choice of these design *** created environment framework is fully open-source and can serve as a benchmark for future research in the RL-OPF field.

关键词： Reinforcement learning Optimal power flow Environment design Economic Dispatch Voltage control Reactive power market

The Role of Childhood Circumstances in Healthy Aging Inequalities Among Older Adults—China,2011–2020

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China CDC weekly 2024年第11期6卷 208-212,I0004-I0007页

作者： Peng nie Xili Lin Lanlin Ding School of Economics and Finance Xi’an Jiaotong UniversityXi’an CityShaanxi ProvinceChina Global Health Institute Xi’an Jiaotong University Health Science CenterXi’an CityShaanxi ProvinceChina National School of Development Peking UniversityBeijingChina

What is already known about this topic?Addressing health disparities is a worldwide priority,with a well-established acknowledgment of the influence of childhood circumstances on these *** China,particularly among the elderly,health inequalities are a notable *** is added by this report?The inequality in healthy aging has increased from 2011 to 2020,both in general and concerning childhood ***,the impact of early-life healthcare access and parental health behaviors on healthy aging gaps has reduced among older adults in better health within the top segment of healthy *** are the implications for public health practice?Efforts towards reducing regional health disparities and improving healthcare access for children,along with promoting the health and well-being of parents,especially in economically disadvantaged households,are crucial policy considerations.

关键词： ledgment inequalities circumstances

Seed-assisted growth for high-performance perovskite solar cells:A review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第9期96卷 588-610页

作者： Zhimin Fang Ting nie Jianning Ding Shengzhong(Frank)Liu Institute of Technology for Carbon Neutralization Yangzhou UniversityYangzhou 225127JiangsuChina Dalian National Laboratory for Clean Energy iChEMDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina Key Laboratory of Applied Surface and Colloid Chemistry Ministry of EducationShaanxi Key Laboratory for Advanced Energy DevicesShaanxi Engineering Lab for Advanced Energy TechnologySchool of Materials Science and EngineeringShaanxi Normal UniversityXi’an 710119ShaanxiChina

The rapid increase in the power conversion efficiency(PCE)of perovskite solar cells(PSCs)is closely related to the development of deposition techinique for perovskite *** high-quality perovskite film enables efficient charge transportation and less trap states,which are eventually translated into enhanced device ***-assisted growth(SAG)is a potential technique for depositing highly-crystallized perovskite films with preferential crystal orientation among the numerous approaches related to crystallization *** this review,we summarize the recent advances in the SAG technique for both one-step and two-step processed perovskite ***,seeding at the buried interface and on the top surface are also *** present different seeds and their corresponding seeding mechanism in detail,such as inorganic nanomaterials,organic ammoniums,alkali metal halides,and perovskite ***,challenges and perspectives are proposed to investigate the potential expansion of seeding engineering in high-performance PSCs,particularly large-area devices.

关键词： Perovskite solar cell Seed Crystallization Efficiency

Convergence analysis for complementary-label learning with kernel ridge regression

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2024年第3期39卷 533-544页

作者： nie Wei-lin WANG Cheng XIE Zhong-hua School of Mathematics and Statistics Huizhou UniversityHuizhou 516007China School of Computer Science and Engineering Huizhou UniversityHuizhou 516007China

Complementary-label learning(CLL)aims at finding a classifier via samples with complementary *** data is considered to contain less information than ordinary-label *** transition matrix between the true label and the complementary label,and some loss functions have been developed to handle this *** this paper,we show that CLL can be transformed into ordinary classification under some mild conditions,which indicates that the complementary labels can supply enough information in most *** an example,an extensive misclassification error analysis was performed for the Kernel Ridge Regression(KRR)method applied to multiple complementary-label learning(MCLL),which demonstrates its superior performance compared to existing approaches.

关键词： multiple complementary-label learning partial label learning error analysis reproducing kernel Hilbert spaces

Polymer-encapsulated metal complex catalysts:An emerging and efficient platform for electrochemical CO_(2) reduction

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2024年第5期172卷 33-50页

作者： Yingshuo Liu Shuaishuai Lyu Fuli Wen Weixuan nie Shuqing Wang Sinopec Research Institute of Petroleum Processing Co. Ltd.Beijing 100083China School of Engineering Westlake UniversityHangzhou 310024China

Over the past decade,electrocatalytic reduction of CO_(2)has gained substantial ***,hardly any of the previous reviews have focused on the systematic discussion of polymer-molecular catalyst composites as an emerging system for the electrochemical transformation of CO_(2)to value-added *** this review,we first give a brief overview of the general features of solid-state and molecular catalysts,and then advance the discussion to polymer-catalyst composite systems,with particular emphasis on polymer-encapsulated molecular catalysts,where the coordination environment surrounding molecular catalysts can be modified via polymer encapsulation to promote the overall performance of CO_(2)*** elucidation of the possible reaction mechanisms of this emerging electrocat-alytic system along with proposed optimization strategies is also summarized and discussed based on recently published reports,followed by the challenges and prospects of their industrial applications at the end of this *** this review,we hope the audience can gain a comprehensive understanding of the electrocatalytic mechanism of the coordinating polymers and valuable insights into engineering the microenvironment surrounding the metal complexes for potential future research directions.

关键词： Polymer-molecular catalyst composite Polymer encapsulation Coordination environment CO_(2)electrocatalysis Electrocatalytic mechanism

Modified Sadowski formula-based model for the slope shape amplification effect under multistage slope blasting vibration

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2024年第5期34卷 631-641页

作者： Xiaogang Wu Mingyang Wang Hao Lu Yongjun Zhang Wen nie State Key Laboratory of Disaster Prevention&Mitigation of Explosion&Impact Army Engineering University of PLANanjing 210007China State Key Laboratory of Metal Mine Safety and Health Ma’anshan 243000China School of Civil Engineering Qingdao University of TechnologyQingdao 266520China

Blasting operations,which are crucial to open-pit mine production due to their simplicity and efficiency,require precise control through accurate vibration velocity *** conventional Sadowski formula mainly focuses on blast center distance but neglects the amplification effect of blasting vibration waves by terraced terrain,from which the calculated blasting vibration velocities are smaller than the actual values,affecting the safety of the *** address this issue,our model introduces the influences of slope and time into Sadowski formula to measure safety through blast vibration *** the northern section of the open-pit quartz mine in Jinchang City,Gansu Province,China,the data of a continuous blasting slope project are referred *** findings reveal a noticeable vibration amplification effect during blasting when a multi-stage slope platform undergoes a sudden cross-sectional change near the upper overhanging *** amplification vibration coefficient increases with height,while vibration waves within rocks decrease from bottom to ***,platforms without distinct crosssectional changes exhibit no pronounced amplification during *** addition,the vibration intensity decreases with distance as the rock height difference change *** results obtained by the proposed blast vibration displacement equation incorporating slope shape influence closely agree with real-world *** to Pearson correlation coefficient(PPMCC)analysis,the average accuracy rate of our model is 88.84%,which exceeds the conventional Sadowski formula(46.92%).

关键词： Multistage slope Slope shape influence factor Continuous blasting Sadowski formula Amplification effect

Cyclic Beam Direction of Arrival Estimation Method for Ship Propeller Noise

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2024年第4期23卷 883-896页

作者： ZHANG Xiaowei nie Weihang XU Ji YAN Yonghong The Key Laboratory of Speech Acoustics and Content Understanding Institute of AcousticsChinese Academy of SciencesBeijing 100190China The Key Laboratory of Speech Acoustics and Content Understanding Institute of AcousticsUniversity of Chinese Academy of SciencesBeijing 100049China The State Key Laboratory of Acoustics Institute of AcousticsChinese Academy of SciencesBeijing 100190China

In underwater acoustic applications,the conventional cyclic direction of arrival algorithm faces challenges,including a low signal-to-noise ratio and high bandwidth when compared with modulated *** response to these issues,this paper introduces a novel,robust,and broadband cyclic beamforming *** proposed method substitutes the conventional cyclic covariance matrix with the variance of the cyclic covariance matrix as its primary *** that the same frequency band shares a common steering vector,the new algorithm achieves superior detection performance for targets with specific modulation frequencies while suppressing interference signals and background *** results demonstrate a significant enhancement in the directibity index by 81%and 181%when compared with the traditional Capon beamforming algorithm and the traditional extended wideband spectral cyclic MUSIC(EWSCM)algorithm,***,the proposed algorithm substantially reduces computational complexity to 1/40th of that of the EWSCM algorithm,employing frequency band statistical averaging and covariance matrix variance.

关键词： cyclostationarity direction of arrival extended wideband spectral cyclic music cyclic covariance matrix