检索结果-南通市图书馆

Coupling Coordination Analysis of Cropland Intensification and Agroecosystem Services:Evidence from Loess Plateau in Shaanxi Province,China

引用

Chinese Geographical Science 2024年第3期34卷 401-419页

作者： fu Shaowu fu Mengyu QIU Menglong Center for Land Resource Research in Northwest China Shaanxi Normal UniversityXi’an 710119China

One of the greatest challenges in the agroecosystem is to improve cropland intensification while preserving agroecosystem *** many studies have investigated the effect of cropland intensification on agroecosystem service,the interactive coupling and coordination among these factors remain largely *** view of this,this study performed a case study of the Loess Plateau in Shaanxi Province,China and constructed comprehensive evaluation models to quantify the cropland intensification and agroecosystem service in this *** analysis and the coupling coordination degree model were used to evaluate the interactive relationship between cropland intensification and agroecosystem service,and statistical analysis and spatial autocorrelation were used to analyze the spatial characteristics and potential mechanism of the coupling *** show that both the cropland intensification and agroecosystem service in the study area were relatively low yet gradually increased from 2000 to *** service lag was identified as the dominant unbalanced development *** the supply capacity of agroecosystem services plays a key role in the balanced development of cropland in the Loess *** coupling coordination degree between cropland intensification and agroecosystem service ranges from basic coordination to serious ***,cropland intensification practices in the area should be optimized to enhance this coordination *** upward trend was also observed in the coupling coordination degree from2000 to *** withdrawal of marginal cropland in the Grain for Green program is one of the most important reasons for this trend,especially for the northern *** 83.6%of the high-high clusters are concentrated in the southern region of the Loess Plateau,whereas 70.5%of the low-low clusters are distributed in the northern *** clustering characteristics are mainly attributed to the environmental

关键词： cropland intensification agroecosystem services balance analysis coupling coordination degree Loess Plateau,China

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Preparation of Al_(72)Ni_8Ti_8Zr_6Nb_3Y_3 amorphous powders and bulk materials

引用

International Journal of Minerals,Metallurgy and Materials 2016年第10期23卷 1187-1195页

作者： Yu Wu Xin-fu Wang fu-sheng Han Key Laboratory of Materials Physics Institute of Solid State Physics Chinese Academy of Sciences

Amorphous Al_（72）Ni_8Ti_8Zr_6Nb_3Y_3 powders were successfully fabricated by mechanical alloying. The microstructure, glass-forming ability, and crystallization behavior of amorphous Al_（72）Ni_8Ti_8Zr_6Nb_3Y_3 powders were investigated by X-ray diffraction（XRD）, transmission electron microscopy（TEM）, and differential scanning calorimetry（DSC）. The isothermal crystallization kinetics was analyzed by the Johnson-Mehl-Avrami equation. In the results, the supercooled liquid region of the amorphous alloy is as high as 81 K, as determined by-non-isothermal DSC curves. The activation energy for crystallization is as high as 312.6 kJ ·mol1 obtained by Kissinger and Ozawa analyses. The values of Avrami exponent（n） imply that the crystallization is dominated by interface-controlled three-dimensional growth in the early stage and the end stage and by diffusion-controlled two- or three-dimensional growth in the middle stage. In addition, the amorphous Al_（72）Ni_8Ti_8Zr_6Nb_3Y_3 powders were sintered under 2 GPa at temperatures of 673 K and 723 K. The results show that the Vickers hardness of the compacted powders is as high as Hv 1215.

关键词： amorphous alloys mechanical alloying thermal stability pressing Vickers hardness

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Constrained minimum power combination for broadband beamformer design in the STFT domain

引用

Frontiers of Computer Science 2017年第3期11卷 408-418页

作者： Zhong-Hua fu School of Computer Science Northwestern Polytechnical University Xi'an 710072 China

Beamforming using sensor array is widely used in spatial signal processing since it offers better spatial focusing capability than single sensor. However, in practical appli- cations for broadband signal, there always exists a trade-off issue between the directivity capability of an array and its robustness on system errors. In this paper, in order to combine merits of different beamformers instead of trade-off their per- formances, we propose a constrained minimum-power com- bination method. We firstly analyze two optimal beamform- ers that maximize Directivity Factor （DF） and White Noise Gain （WNG） respectively. Then we propose a non-linear combination method, which automatically selects the best beamformer that has the minimum output power, so as to control the unwanted white noise amplification and keep the maximum DF if possible. Two solutions to the proposed com- bination strategy are given. They do not need to determine the correct trade-off factor used in linear combination method, and avoid challenge ~stimations on noise and target statistics required in adaptive beamforming. The performance of the proposed beamformer is evaluated in ideal noise fields and complicated noise fields respectively. It is shown that the proposed beamformer integrates merits of different beamform- ers. It always achieves the best speech quality and biggest noise reduction compared to other popular beamformers.

关键词： robust beamforming directivity index white noise gain broadband STFT domain speech enhancement

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

醒脑开窍针刺法合并补肾化痰活血方治疗急性脑梗死风痰瘀阻证的临床研究

引用

中医药学报 2025年第1期53卷 83-87页

作者：付飞樊飞北京中医药大学孙思邈医院脑病科陕西铜川727000

目的:探究醒脑开窍针刺法合并补肾化痰活血方治疗急性脑梗死风痰瘀阻证的临床效果。方法:选择北京中医药大学孙思邈医院2021年1月-2023年12月收治的急性脑梗死风痰瘀阻证患者106例,采用随机数字表法分为针刺组和联合组,每组53例。两组... 详细信息

目的:探究醒脑开窍针刺法合并补肾化痰活血方治疗急性脑梗死风痰瘀阻证的临床效果。方法:选择北京中医药大学孙思邈医院2021年1月-2023年12月收治的急性脑梗死风痰瘀阻证患者106例,采用随机数字表法分为针刺组和联合组,每组53例。两组均给予抗凝、改善微循环、控制血压、神经保护、吸氧、心脏监测等常规西医治疗,针刺组给予醒脑开窍针刺法治疗,联合组在针刺组基础上给予补肾化痰活血方口服治疗。观察两组患者的中医证候积分、神经功能指标、血流动力学指标、神经功能与运动功能及日常生活能力评分、临床疗效、不良反应发生情况。结果:治疗后,两组中医证候积分、美国国立卫生研究院卒中量表(NIHSS)评分、神经胶质纤维酸性蛋白(GFAP)、神经元特异性烯醇化酶(NSE)、中枢神经特异蛋白(S100β)、血流峰值时间(TTP)与阻力指数(RI)水平均较治疗前降低(Pfugl-Meyer评分(FMA)与Barthel指数(BI)评分均较治疗前升高(P0.05)。结论:醒脑开窍针刺法合并补肾化痰活血方治疗急性脑梗死风痰瘀阻证可降低中医证候积分,缓解临床症状,增加脑血流量,改善神经功能,提高临床疗效,且安全性较高。

关键词：醒脑开窍针刺法补肾化痰活血方急性脑梗死风痰瘀阻证

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Local holographic transformations:tractability and hardness

引用

Frontiers of Computer Science 2023年第2期17卷 167-177页

作者： Peng YANG Zhiguo fu School of Information Science and Technology&KLAS Northeast Normal UniversityChangchun 130117China

Local holographic transformations were introduced by Cai et al.,and local affine functions,an extra tractable class,were derived by it in#CSP^(2).In the present paper,we not only generalize local affine functions to#CSP^(d)for general d,but also give new tractable classes by combining local holographic transformations with global holographic ***,we show how to use local holographic transformations to prove *** is of independent interests in the complexity classification of counting problems.

关键词： #CSP^(d) Holant problems local holographic transformations

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Convergence Rate Analysis of Gaussian Belief Propagation for Markov Networks

引用

IEEE/CAA Journal of Automatica Sinica 2020年第3期7卷 668-673页

作者： Zhaorong Zhang Minyue fu School of Electrical Engineering and Computer Science The University of Newcastle.University DriveNSW 2308Australia IEEE School of Automation Guangdong University of Technologyand Guangdong Key Laboratory of Intelligent Decision and Cooperative ControlGuangzhou 510006China

Gaussian belief propagation algorithm(GaBP) is one of the most important distributed algorithms in signal processing and statistical learning involving Markov networks. It is well known that the algorithm correctly computes marginal density functions from a high dimensional joint density function over a Markov network in a finite number of iterations when the underlying Gaussian graph is acyclic. It is also known more recently that the algorithm produces correct marginal means asymptotically for cyclic Gaussian graphs under the condition of walk summability(or generalised diagonal dominance). This paper extends this convergence result further by showing that the convergence is exponential under the generalised diagonal dominance condition,and provides a simple bound for the convergence rate. Our results are derived by combining the known walk summability approach for asymptotic convergence analysis with the control systems approach for stability analysis.

关键词： Belief propagation distributed algorithm distributed estimation Gaussian belief propagation Markov networks

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A cooperative detection game:UAV swarm *** fast intruder

引用

Journal of Systems Engineering and Electronics 2023年第6期34卷 1565-1575页

作者： XIAO Zhiwen fu Xiaowei School of Electronics and Information Northwestern Polytechnical UniversityXi’an 710129China

This paper studies a special defense game using unmanned aerial vehicle(UAV)swarm against a fast *** fast intruder applies an offensive strategy based on the artificial potential field method and Apollonius circle to scout a certain *** defenders,the UAVs are arranged into three layers:the forward layer,the midfield layer and the back *** co-defense mechanism,including the role derivation method of UAV swarm and a guidance law based on the co-defense front point,is introduced for UAV swarm to co-detect the ***,five formations are designed for comparative analysis when ten UAVs are *** Monte Carlo experiments and ablation experiment,the effectiveness of the proposed co-defense method has been verified.

关键词： cooperative detection game unmanned aerial vehicle(UAV)swarm fast intruder defensive strategy co-defense mechanism.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Incorporating Variation and Quality of the Underlying Effects in Meta-Analysis

引用

Journal of Systems Science & Complexity 2022年第6期35卷 2381-2397页

作者： fu Jinyu LIN Jinguan School of Mathematics Southeast UniversityNanjing 210096China School of Statistics and Data Science Nanjing Audit UniversityNanjing 211815China

This paper proposes a model to further explore the effects of the quality information and variation of the underlying effects on the summary effect measure in meta-analysis.A shape parameter is used in this model to quantify the asymmetry of the effect sizes of studies that are *** of the proposed model parameters is carried out by the Bayesian MCMC *** of the resultant estimates are examined in the simulations and empirical case with data obtained from a total of 22 meta-analyses taken from three different designs.A conclusion would be drawn that it is advisable to take the proposed model,when quality information becomes available,in particular with a situation where the underlying effects approximately follow a normal ***,however,the quality information is absent,the skew-normal distribution for random effect model should be adopted.

关键词： Bayesian estimation heterogeneity overall effect size quality score skew-normal distribution

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Component reallocation and system replacement maintenance based on availability and cost in series systems

引用

Journal of Systems Engineering and Electronics 2022年第6期33卷 1342-1353页

作者： fu Yuqiang MA Xiaoyang School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083China School of Information Management Beijing Information Science&Technology UniversityBeijing 100192China

Component reallocation(CR)is receiving increasing attention in many engineering systems with functionally interchangeable and unbalanced degradation *** paper studies a CR and system replacement maintenance policy of series repairable systems,which undergoes minimal repairs for each emergency failure of components,and considers constant downtime and cost of minimal repair,CR and system *** binary mixed integer nonlinear programming models are respectively established to determine the assignment of CR,and the uptime right before CR and system replacement with the objective of minimizing the system average maintenance cost and maximizing the system ***,we derive the optimal uptime right before system replacement with maximization of the system availability,and then give the relationship between the system availability and the component failure ***,numerical examples show that the CR and system replacement maintenance policy can effectively reduce the system average maintenance cost and improve the system availability,and further give the sensitivity analysis and insights of the CR and system replacement maintenance policy.

关键词： component reallocation(CR) system replacement maintenance cost availability binary mixed integer nonlinear programming minimal repair

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Hydrodynamic Performance of A Dual-Floater Integrated System Com-bining Hybrid WECs and Floating Breakwaters

引用

China Ocean Engineering 2022年第6期36卷 969-979页

作者： fu Lei CHENG Yong School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China

The high investment and low return of wave energy converters(WECs)seriously hamper their large-scale commercial *** integration of WECs and floating breakwaters is conducive to enhance the competitiveness of wave energy *** objective of this paper is to investigate the hydrodynamic performance of a WEC-breakwater integrated system combining an upstream oscillating water column(OWC)and a downstream oscillating buoy(OB)via numerical simulations and physical experiments.A nonlinear numerical wave flume using Star-CCM+software is employed to obtain calculated results,where a tiny transverse gap is set between the flume wall and the block surface to simulate a similar two-dimensional(2D)*** corresponding physical experiments are also carried out in a practical wave flume to verified the numerical *** comparison of the isolated and hybrid system shows that the hybrid design leads to the decreased conversion efficiency of each WEC,but improves the transmission performance of the hybrid *** wave resonance between two devices causes the abrupt reduction of OWC efficiency and a positive correlation exists with the OB *** total efficiency of the hybrid system is raised by an optimal opening ratio,a shallow OWC draft and a short spacing *** for the OWC draft,other design parameters have weak effect on the wave attenuation of the hybrid *** paper can help understand hydrodynamics of the hybrid WECs integrated with breakwaters and improve their performances.

关键词： wave energy converters floating breakwater oscillating buoy oscillating water column numerical wave flume physical experiment

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：