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Dynamic spillovers between the term structure of interest rates,bitcoin,and safe‑haven currencies 被引量:4
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作者 David Y.Aharon Zaghum Umar Xuan Vinh Vo 《Financial Innovation》 2021年第1期1334-1358,共25页
This study examines the connectedness between the US yield curve components(i.e.,level,slope,and curvature),exchange rates,and the historical volatility of the exchange rates of the main safe-haven fiat currencies(Can... This study examines the connectedness between the US yield curve components(i.e.,level,slope,and curvature),exchange rates,and the historical volatility of the exchange rates of the main safe-haven fiat currencies(Canada,Switzerland,EURO,Japan,and the UK)and the leading cryptocurrency,the Bitcoin.Results of the static analysis show that the level and slope of the yield curve are net transmitters of shocks to both the exchange rate and its volatility.The exchange rate of the Euro and the volatility of the Euro and the Canadian dollar exchange rate are net transmitters of shocks.Meanwhile,the curvature of the yield curve and the Japanese Yen,Swiss Franc,and British Pound act mainly as net receivers.Our static connectedness analysis shows that Bitcoin is mainly independent of shocks from the yield curve’s level,slope,and curvature,and from any main currency investigated.These findings hint that Bitcoin might provide hedging benefits.However,similar to the static analysis,our dynamic analysis shows that during different periods and particularly in stressful times,Bitcoin is far from being isolated from other currencies or the yield curve components.The dynamic analysis allows us to observe Bitcoin’s connectedness in times of stress.Evidence supporting this contention is the substantially increased connectedness due to policy shocks,political uncertainty,and systemic crisis,implying no empirical support for Bitcoin’s safe-haven property during stress times.The increased connectedness in the dynamic analysis compared with the static approach implies that in normal times and especially in stressful times,Bitcoin has the property of a diversifier.The results may have important implications for investors and policymakers regarding their risk monitoring and their assets allocation and investment strategies. 展开更多
关键词 Bitcoin term structure slope CURVATURE Diebold and Yilmaz Connectedness Cryptocurrency FOREX CURRENCIES Safe haven
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Volatility Structures of ForwardRates and the Dynamics of the TermStructure:a Multifactor Case
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作者 Wang Guilan(College of Mathematical Sciences, Wuhan University, Wuhan 430072, China) 《Wuhan University Journal of Natural Sciences》 CAS 1998年第4期397-402,共6页
For general volatility structures for forward rates, the evolution of interest rates may not be Markovian and the entire path may be necessary to capture the dynamics of the term structure. This article identifies con... For general volatility structures for forward rates, the evolution of interest rates may not be Markovian and the entire path may be necessary to capture the dynamics of the term structure. This article identifies conditions on the volatility structure of forward rates that permit the dynamics of the term structure to be represented by a finite-dimensional state variable Markov process. In the deterministic volatility case, we interpret then-factor model as a sum ofn unidimensional models. 展开更多
关键词 term structure dynamics volatility of forward rates HJM models Markovian models of the term structure
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Effects of Long-term Fertilization on Soil M icrobial Com m unity Structure,Labile Organic Carbon and Nitrogen and Enzym e Activity in Paddy Field and Upland 被引量:4
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作者 Wang Guiyue Su Ting +3 位作者 Han Hailiang Tan Heping Bao Fei Zhao Fucheng 《Meteorological and Environmental Research》 CAS 2019年第5期105-111,共7页
To investigate the effects of long-term fertilization systems on soil microbial community structure,labile organic carbon and nitrogen and enzyme activity in yellow sand paddy field and upland,a field experiment was c... To investigate the effects of long-term fertilization systems on soil microbial community structure,labile organic carbon and nitrogen and enzyme activity in yellow sand paddy field and upland,a field experiment was conducted at the experimental station of Dongyang Institute of Maize Research in Zhejiang Province,China in 2009.The experiment consisted of six treatments with three replicates,and they were arranged in a completely randomized design,including no fertilization in paddy field (PCK),conventional fertilization in paddy field (PCF),formulated fertilization by soil testing in paddy field (PSTF),formulated fertilization by soil testing with organic manure in paddy field (PSTF+OF),conventional fertilization on upland (DCF),and formulated fertilization by soil testing with organic manure on upland (DSTF+OF).Soil nutrients,enzyme activity,microbial biomass and community structure were determined in 2015.The results showed that compared with no fertilization in paddy field (PCK),fertilization increased soil phosphorus and potassium content,and decreased pH value.No fertilization in paddy field (PCK) had no significant effect on soil culturable microorganisms in paddy field and upland,but formulated fertilization by soil testing with organic manure on upland (DSTF+OF) significantly increased the number of fungi.Formula fertilization by soil testing with organic manure (PSTF+OF) also significantly increased soil microbial biomass carbon and nitrogen in paddy field and upland.Moreover,fertilization had no significant effect on soil cellulase activity,but formula fertilization by soil testing with organic manure (PSTF+OF) significantly increased soil dehydrogenase and catalase activity.Therefore,long-term application of chemical fertilizer with organic fertilizer can effectively improve soil fertility. 展开更多
关键词 Long-term fertilization Paddy field UPLAND Microbial community structure SOIL enzyme ACTIVITY
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Use of nonlinear variable structure control with equivalent term in design of coordinated controls for turbo generators
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作者 于浩 刘瑞叶 陈学允 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2000年第2期71-74,共4页
Presents the coordinated controls of nonlinear variable structure with an equivalent control term designed for turbo generators following the theory of nonlinear variable structure control, which integrates the valve ... Presents the coordinated controls of nonlinear variable structure with an equivalent control term designed for turbo generators following the theory of nonlinear variable structure control, which integrates the valve control with the excitation control and reduce the problem of high frequency shiver with conventional variable structure control in addition to a simplified design, and concludes from simulation results that the use of this control can improve the transient of the system. 展开更多
关键词 NONLINEAR variable structure CONTROL EQUIVALENT CONTROL term VALVE CONTROL excitation CONTROL
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Simulation Methods of Stochastic Volatility Interest Rate Term Structure
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作者 冉伦 周丽 陈倩 《Journal of Beijing Institute of Technology》 EI CAS 2010年第1期121-126,共6页
A term structure model bearing features of stochastic volatility and stochastic mean drift with jump (SVJ-SD model for short) is built in the paper to describe the stochastic behavior of interest rates.Based on samp... A term structure model bearing features of stochastic volatility and stochastic mean drift with jump (SVJ-SD model for short) is built in the paper to describe the stochastic behavior of interest rates.Based on sample data of an interest rate of national bond repurchase,maximum likelihood (ML),linear Kalman filter and efficient method of moments (EMM) are used to estimate the model.While ML works well for simple models,it may lead to considerable deviation in parameter estimation when dynamic risks of interest rates are considered in them.Linear Kalman filter is a tractable and reasonably accurate technique for estimation cases where ML was not feasible.Moreover,when compared with the first two approaches,using EMM can obtain better parameter estimates for complex models with non-affine structures. 展开更多
关键词 interest rate term structure stochastic volatility efficient method of moment maximum likelihood Kalman filter
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Term Structure of Interest Rates Based on Artificial Neural Network
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作者 姜德峰 杜子平 《Journal of Southwest Jiaotong University(English Edition)》 2007年第4期338-343,共6页
In light of the nonlinear approaching capability of artificial neural networks ( ANN), the term structure of interest rates is predicted using The generalized regression neural network (GRNN) and back propagation ... In light of the nonlinear approaching capability of artificial neural networks ( ANN), the term structure of interest rates is predicted using The generalized regression neural network (GRNN) and back propagation (BP) neural networks models. The prediction performance is measured with US interest rate data. Then, RBF and BP models are compared with Vasicek's model and Cox-Ingersoll-Ross (CIR) model. The comparison reveals that neural network models outperform Vasicek's model and CIR model, which are more precise and closer to the real market situation. 展开更多
关键词 Neural network Interest rate term structure Generalized regression neural network
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Empirical Estimation of Term Structure of Interbank Rates in China
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作者 闵晓平 《Journal of Southwest Jiaotong University(English Edition)》 2006年第3期285-290,共6页
Nelson-Siegel model ( NS model) and 2 extended NS models were compared by using daily interbank government bond data Based on the grouping of bonds according to the residual term to maturity, the empirical research ... Nelson-Siegel model ( NS model) and 2 extended NS models were compared by using daily interbank government bond data Based on the grouping of bonds according to the residual term to maturity, the empirical research proceeded with in-sample and outof-sample tests. The results show that the 3 models are almost equivalent in estimating interbank term structure of interest rates. Within the term to maturities between 0 and 7 years, the gap of the absolute errors of the 3 models between in-sample and out-of-sample is smRller than 0.2 Yuan, and the absolute values of the in-sample and out-of-sample errors are smaller than 0. 1 Yuan, so the estimation is credible. Within the term to maturities between 7 and 20 years, the gap of the absolute errors of the 3 models between in-sample and out-of-sample is larger than 0.4 Yuan, and the absolute values of the in-sample and out-of-sample errors are larger than 1.0 Yuan, so the estimation is incredible. 展开更多
关键词 Interbank bond market term structure of interest rate ESTIMATION
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Cultural Structure of Solar Terms and Traditional Festivals
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作者 Tao Siyan Wu Lingwei 《Contemporary Social Sciences》 2018年第5期131-140,共10页
Solar terms and festivals differ from and relate to each other in terms of application scope and cultural structure.The cultural association and application of the 24 Solar Terms are studied in the areas including phi... Solar terms and festivals differ from and relate to each other in terms of application scope and cultural structure.The cultural association and application of the 24 Solar Terms are studied in the areas including philosophy,farming and society,and are exhibited in the natural convergence of views on space and time,life and customs,as well as the facilitation of agricultural practice.The connotations of traditional Chinese festivals concern basic areas such as beliefs,rites,language,symbols,diets and art,which are exhibited in the co-existent "festival tokens," "festival events," "festival messages," "festival symbols," "festival food" and "festival art forms." Festivals feature fixed and periodic occurrence and multi-channel cultural inheritance. 展开更多
关键词 solar term traditional festival connotative space application area cultural structure
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Perturbation Analysis of Structured Least Squares Problems and Its Application in Calibration of Interest Rate Term Structure 被引量:1
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作者 Chen Zhao Weiguo Gao Jungong Xue 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 2007年第4期383-392,共10页
A structured perturbation analysis of the least squares problem is considered in this paper.The new error bound proves to be sharper than that for general perturbations. We apply the new error bound to study sensitivi... A structured perturbation analysis of the least squares problem is considered in this paper.The new error bound proves to be sharper than that for general perturbations. We apply the new error bound to study sensitivity of changing the knots for curve fitting of interest rate term structure by cubic spline.Numerical experiments are given to illustrate the sharpness of this bound. 展开更多
关键词 线性函数 最小平方问题 扰动分析 数学分析
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Modelling the Term Structure of Hong Kong Inter-Bank Offered Rates (HIBOR)
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作者 Sandy Chau Andy Tai Wilson Kwan 《Economics World》 2016年第1期7-16,共10页
关键词 世界经济 经济增长 政策 规划
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A Study on Hydroelastic Response of Box-Type Very Large Floating Structures
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作者 王志军 李润培 舒志 《China Ocean Engineering》 SCIE EI 2001年第3期345-354,共10页
The application of very large floating structure (VLFS) to the utilization of ocean space and exploitation of ocean resources has become one of the issues of great interest in international ocean engineering field. Ow... The application of very large floating structure (VLFS) to the utilization of ocean space and exploitation of ocean resources has become one of the issues of great interest in international ocean engineering field. Owing to the advantage of simplicity in structure and low cost of construction and maintenance, box-type VLFS can be used in the calm water area near the coast as the structure configuration of floating airport. In this paper, a 3D linear hydroelastic theory is used to study the dynamic response of box-type VLFS in sinusoidal regular waves. A beam model and a 3D FEM model are respectively employed to describe the dynamic characteristics of the box-type Structure in vacuum. A hydrodynamic model (3D potential theory of flexible body) is applied to investigate the effect of different dry models on the hydroelastic response of box-type structure. Based on the calculation of hydroelastic response in regular waves, the rigid body motion displacement, flexible deflection, and the short term and long term wave induced bending moments are also predicted. 展开更多
关键词 box-type VLFS hydroelastic response dry structure short term prediction long tern prediction
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Structured scene modeling using micro stereo vision system with large field of view
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作者 颜世莹 朱玉文 +1 位作者 刘佳音 贾云得 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2001年第3期296-299,共4页
This paper presents a method for structured scene modeling using micro stereo vision system with large field of view. The proposed algorithm includes edge detection with Canny detector, line fitting with principle axi... This paper presents a method for structured scene modeling using micro stereo vision system with large field of view. The proposed algorithm includes edge detection with Canny detector, line fitting with principle axis based approach, finding corresponding lines using feature based matching method, and 3D line depth computation. 展开更多
关键词 Index terms structured scene modeling stereo vision wide field of view mobile robot
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Extractive Summarization Using Structural Syntax, Term Expansion and Refinement
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作者 Mohamed Taybe Elhadi 《International Journal of Intelligence Science》 2017年第3期55-71,共17页
This paper investigates a procedure developed and reports on experiments performed to studying the utility of applying a combined structural property of a text’s sentences and term expansion using WordNet [1] and a l... This paper investigates a procedure developed and reports on experiments performed to studying the utility of applying a combined structural property of a text’s sentences and term expansion using WordNet [1] and a local thesaurus [2] in the selection of the most appropriate extractive text summarization for a particular document. Sentences were tagged and normalized then subjected to the Longest Common Subsequence (LCS) algorithm [3] [4] for the selection of the most similar subset of sentences. Calculated similarity was based on LCS of pairs of sentences that make up the document. A normalized score was calculated and used to rank sentences. A selected top subset of the most similar sentences was then tokenized to produce a set of important keywords or terms. The produced terms were further expanded into two subsets using 1) WorldNet;and 2) a local electronic dictionary/thesaurus. The three sets obtained (the original and the expanded two) were then re-cycled to further refine and expand the list of selected sentences from the original document. The process was repeated a number of times in order to find the best representative set of sentences. A final set of the top (best) sentences was selected as candidate sentences for summarization. In order to verify the utility of the procedure, a number of experiments were conducted using an email corpus. The results were compared to those produced by human annotators as well as to results produced using some basic sentences similarity calculation method. Produced results were very encouraging and compared well to those of human annotators and Jacquard sentences similarity. 展开更多
关键词 Data Extractive SUMMARIZATION Syntactical structures Sentence Similarity Longest Common SUBSEQUENCE term EXPANSION WORDNET Local THESAURUS
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Microbial community structure and functional metabolic diversity are associated with organic carbon availability in an agricultural soil 被引量:5
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作者 LI Juan LI Yan-ting +3 位作者 YANG Xiang-dong ZHANG Jian-jun LIN Zhi-an ZHAO Bing-qiang 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2015年第12期2500-2511,共12页
Exploration of soil environmental characteristics governing soil microbial community structure and activity may improve our understanding of biogeochemical processes and soil quality. The impact of soil environmental ... Exploration of soil environmental characteristics governing soil microbial community structure and activity may improve our understanding of biogeochemical processes and soil quality. The impact of soil environmental characteristics especially organic carbon availability after 15-yr different organic and inorganic fertilizer inputs on soil bacterial community structure and functional metabolic diversity of soil microbial communities were evaluated in a 15-yr fertilizer experiment in Changping County, Beijing, China. The experiment was a wheat-maize rotation system which was established in 1991 including four different fertilizer treatments. These treatments included: a non-amended control(CK), a commonly used application rate of inorganic fertilizer treatment(NPK); a commonly used application rate of inorganic fertilizer with swine manure incorporated treatment(NPKM), and a commonly used application rate of inorganic fertilizer with maize straw incorporated treatment(NPKS). Denaturing gradient gel electrophoresis(DGGE) of the 16 S r RNA gene was used to determine the bacterial community structure and single carbon source utilization profiles were determined to characterize the microbial community functional metabolic diversity of different fertilizer treatments using Biolog Eco plates. The results indicated that long-term fertilized treatments significantly increased soil bacterial community structure compared to CK. The use of inorganic fertilizer with organic amendments incorporated for long term(NPKM, NPKS) significantly promoted soil bacterial structure than the application of inorganic fertilizer only(NPK), and NPKM treatment was the most important driver for increases in the soil microbial community richness(S) and structural diversity(H). Overall utilization of carbon sources by soil microbial communities(average well color development, AWCD) and microbial substrate utilization diversity and evenness indices(H' and E) indicated that long-term inorganic fertilizer with organic amendments incorporated(NPKM, NPKS) could significantly stimulate soil microbial metabolic activity and functional diversity relative to CK, while no differences of them were found between NPKS and NPK treatments. Principal component analysis(PCA) based on carbon source utilization profiles also showed significant separation of soil microbial community under long-term fertilization regimes and NPKM treatment was significantly separated from the other three treatments primarily according to the higher microbial utilization of carbohydrates, carboxylic acids, polymers, phenolic compounds, and amino acid, while higher utilization of amines/amides differed soil microbial community in NPKS treatment from those in the other three treatments. Redundancy analysis(RDA) indicated that soil organic carbon(SOC) availability, especially soil microbial biomass carbon(Cmic) and Cmic/SOC ratio are the key factors of soil environmental characteristics contributing to the increase of both soil microbial community structure and functional metabolic diversity in the long-term fertilization trial. Our results showed that long-term inorganic fertilizer and swine manure application could significantly improve soil bacterial community structure and soil microbial metabolic activity through the increases in SOC availability, which could provide insights into the sustainable management of China's soil resource. 展开更多
关键词 long-term fertilization regimes organic amendment soil microbial community structure microbial functional metabolic activity carbon substrate utilization
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MICROSTRUCTURES AND THE STRUCTURE STABILITY OF INCONEL 725, A NEW AGE-HARDENABLE CORROSION RESISTANT SUPERALLOY
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作者 J.X.Dong M.C.Zhang S.K.Mannan 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2003年第2期145-150,共6页
INCONEL725 is a highly corrosion resistant nickel based alloy capable of being age-hardened to high strength levels. The micro structure observations and the phase identification after a standard heat treatment were i... INCONEL725 is a highly corrosion resistant nickel based alloy capable of being age-hardened to high strength levels. The micro structure observations and the phase identification after a standard heat treatment were investigated. The results show that the precipitation phases include the strengthening phasesγ', γ', and 8 phase, primary carbide phase TiC, as well as M6 C carbide and a little extent MC (mainly TiC) precipitates which nucleate mainly at grain boundaries. An isothermal aging study was carried out on this alloy for up to 10 000 hours at 593℃. This additional aging did not affect the tensile strength. However, micro structures show that the thermal exposure has a little additional effect. With increasing the exposure time, the size of γ' phase slightly increases, almost no change for γ' phase, while M6C carbides precipitated at grain boundaries have an increased and complex tendency on a few grain boundaries. The experimental results illustrate the excellent structure stability of the age-hardenable IN725 at 593℃. 展开更多
关键词 SUPERALLOY INCONEL725 micro structure long-term exposure
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Study on basement structures of the northeast Pamirs
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作者 段永红 张先康 杨卓欣 《Acta Seismologica Sinica(English Edition)》 CSCD 2002年第4期395-401,共7页
Basement structures and basement interfaces are obtained by finite-difference and time-term methods using Pg-wave data from two deep seismic sounding (DSS) profiles in the Artush-Jiashi strong earthquake area. The geo... Basement structures and basement interfaces are obtained by finite-difference and time-term methods using Pg-wave data from two deep seismic sounding (DSS) profiles in the Artush-Jiashi strong earthquake area. The geological units differ considerably in basement depth. The basement structures of contact zones between two geological units also vary obviously, which marks the existence of boundary faults. Finally, we make a remark upon the relationship between characteristics of basement structures and seismicity in the Artush meizoseismal area and the Jiashi earthquake swarm area. 展开更多
关键词 northeast Pamirs basement structure finite-difference tomography time-term method meizoseismal area
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大跨度斜拉桥模态参数长期追踪及其变异性分析 被引量:1
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作者 茅建校 桂桂 +1 位作者 王浩 杨朝勇 《振动工程学报》 EI CSCD 北大核心 2024年第1期52-59,共8页
为了丰富大跨度斜拉桥模态参数的实测数据库,依托苏通大桥结构健康监测系统采集的数据,采用所建立的模态自动识别和追踪方法,获取了2010年期间该桥的模态参数值,并据此分析了在温度和风速作用下桥梁模态参数的变异性。研究结果表明,大... 为了丰富大跨度斜拉桥模态参数的实测数据库,依托苏通大桥结构健康监测系统采集的数据,采用所建立的模态自动识别和追踪方法,获取了2010年期间该桥的模态参数值,并据此分析了在温度和风速作用下桥梁模态参数的变异性。研究结果表明,大桥主梁模态频率的变化受温度和风速共同影响,随着温度的升高而降低,随着风速的升高而增加。大桥主梁模态阻尼比的变异性显著大于模态频率,低风速下主梁一阶侧弯阻尼比在0.5%~15%之间波动,风速大于9 m/s时逐渐降低并稳定在2%左右。大桥主梁前四阶竖弯阻尼比受气动阻尼的影响较大,在风速较小时随着风速的增加略有增加。研究结果可为大桥的服役性能评估与运营管理提供参考。 展开更多
关键词 大跨度斜拉桥 模态参数 结构健康监测 长期追踪 变异性
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高质量发展视域下的中国人口均衡发展 被引量:1
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作者 宋健 《四川大学学报(哲学社会科学版)》 北大核心 2024年第2期55-62,210,共9页
在人口形势发生重要转折性变化之际,高质量发展要求更加重视人口素质,以“提质”替代“增量”,以“人才”替代“人力”,充分发挥凝结在人口自身的素质要素的作用,使更多民众更好地享受高质量发展的成果,享受高品质生活。长期均衡发展是... 在人口形势发生重要转折性变化之际,高质量发展要求更加重视人口素质,以“提质”替代“增量”,以“人才”替代“人力”,充分发挥凝结在人口自身的素质要素的作用,使更多民众更好地享受高质量发展的成果,享受高品质生活。长期均衡发展是人口发展的主要目标,也是人口高质量发展的内在要求。人口均衡发展不仅体现在人口系统内部要素间的依存制约以及人口系统与社会经济系统之间的协调适应,还体现在代际间的传承永续。年龄结构失衡是当前人口非均衡发展的突出表现,应聚焦结构失衡,弥补制约人口均衡发展的短板;同时充分发挥作为人口结构中坚力量的劳动年龄人口的作用,通过与经济高质量发展相协调以及推动人口均衡分布,促进人口均衡发展,助力实现人口高质量发展。 展开更多
关键词 人口高质量发展 人口长期均衡发展 结构均衡
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基于岩石CT扫描的冻融作用对花岗岩细观结构及力学强度影响研究
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作者 侯圣山 何箫 +6 位作者 孟宪森 陈亮 冯振 刘明学 李昂 郭长宝 吉锋 《地质力学学报》 CSCD 北大核心 2024年第3期462-472,共11页
近年来随着西部地区的基础工程建设数量及规模不断增加,西部高原地区的季节性冻融循环效应的影响也随之增强,开展冻融循环作用下岩石细观特性及强度劣化性质研究对指导西部寒区基础工程建设至关重要。首先在偏光显微镜下对岩石薄片进行... 近年来随着西部地区的基础工程建设数量及规模不断增加,西部高原地区的季节性冻融循环效应的影响也随之增强,开展冻融循环作用下岩石细观特性及强度劣化性质研究对指导西部寒区基础工程建设至关重要。首先在偏光显微镜下对岩石薄片进行观察,获取岩石的矿物成分和微结构;接着利用CT扫描技术,对冻融后的花岗岩进行扫描,对扫描图层利用阈值分割进行二值化处理,堆叠得到样品内外结构的高分辨3D数据及影像;结合分形理论计算图像计盒维数并由此对图像复杂度做出量化判断,由此对冻融循环对花岗岩内部结构演化分布特点进行分析;进而揭示其强度演化规律,探究结构演化与强度之间的关系。偏光显微镜下,岩石呈块状构造,具有似斑状粗粒不等粒花岗结构,局部见交代蠕虫结构。似斑晶矿物主要为碱性长石;其他矿物粒径0.25~4.0 mm为主,矿物成分主要为石英、斜长石、碱性长石,次要矿物为黑云母、绿帘石,副矿物有磷灰石、锆石、黄铁矿等,镜下鉴定为似斑状粗粒不等粒黑云二长花岗岩。CT扫描显示,冻融循环效应在影响花岗岩细观结构时,会导致花岗岩内部孔隙率的整体上升,但岩石渗透性变化不大,岩石渗透率仅上升0.003×10^(-3)μm^(2);内部孔隙发育不均匀,试样整体结构改变以萌生较多新的微孔隙为主。冻融循环后岩石内部结构复杂度有所下降,但岩石整体完整性仍然较好,分形维数仍保持在较高水平。分形研究显示,20次冻融循环并未导致花岗岩的结构复杂度发生较大变化,同时试样整体力学特性出现下降,黏性增加以及长期强度出现较大幅度的衰减,进入蠕变试验阶段的应变阈值提高。在评价此类原生结构较致密的岩石的安全性时,仅从结构上进行考量与实际情况往往会出现偏差,应结合必要的强度指标综合评估。岩石在经历冻融循环后,在强度更低的同时会发生更大的变形。该研究可为分形理论在岩石细观结构演化方面的应用及岩石细观结构与强度演化相关研究提供借鉴,并对高寒地区工程施工有指导意义。 展开更多
关键词 冻融循环 阈值分割 CT模型 分形维数 结构演化 长期强度
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教育供给侧结构性改革视角下高校创新创业教育的长效机制构建
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作者 王艺 原光 《青岛职业技术学院学报》 2024年第1期12-19,共8页
教育供给侧结构性改革是当前教育领域的关键议题,强调教育供给主体的协同、要素的优化配置和制度的保障,以促进供需衔接,推动“大众创新,万众创业”。高校以此理论为指导,积极建立“国家—高校—企业外循环”和“高校管理人员—教师—... 教育供给侧结构性改革是当前教育领域的关键议题,强调教育供给主体的协同、要素的优化配置和制度的保障,以促进供需衔接,推动“大众创新,万众创业”。高校以此理论为指导,积极建立“国家—高校—企业外循环”和“高校管理人员—教师—学生内循环”的协同机制,构建三维合一的长效发展模式,有助于解决高等教育中存在的协同碎片化、要素融合难、制度供给不足等问题,推动创新人才培养,促进学科、技术融合,培养大学生创新意识和创业精神,推动高校创新创业教育的可持续发展。 展开更多
关键词 教育供给侧结构性改革 供给侧结构性改革 高等教育 创新创业教育 长效机制
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