期刊文献+
共找到35,720篇文章
< 1 2 250 >
每页显示 20 50 100
Projecting Wintertime Newly Formed Arctic Sea Ice through Weighting CMIP6 Model Performance and Independence 被引量:1
1
作者 Jiazhen ZHAO Shengping HE +2 位作者 Ke FAN Huijun WANG Fei LI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第8期1465-1482,共18页
Precipitous Arctic sea-ice decline and the corresponding increase in Arctic open-water areas in summer months give more space for sea-ice growth in the subsequent cold seasons. Compared to the decline of the entire Ar... Precipitous Arctic sea-ice decline and the corresponding increase in Arctic open-water areas in summer months give more space for sea-ice growth in the subsequent cold seasons. Compared to the decline of the entire Arctic multiyear sea ice,changes in newly formed sea ice indicate more thermodynamic and dynamic information on Arctic atmosphere–ocean–ice interaction and northern mid–high latitude atmospheric teleconnections. Here, we use a large multimodel ensemble from phase 6 of the Coupled Model Intercomparison Project(CMIP6) to investigate future changes in wintertime newly formed Arctic sea ice. The commonly used model-democracy approach that gives equal weight to each model essentially assumes that all models are independent and equally plausible, which contradicts with the fact that there are large interdependencies in the ensemble and discrepancies in models' performances in reproducing observations. Therefore, instead of using the arithmetic mean of well-performing models or all available models for projections like in previous studies, we employ a newly developed model weighting scheme that weights all models in the ensemble with consideration of their performance and independence to provide more reliable projections. Model democracy leads to evident bias and large intermodel spread in CMIP6 projections of newly formed Arctic sea ice. However, we show that both the bias and the intermodel spread can be effectively reduced by the weighting scheme. Projections from the weighted models indicate that wintertime newly formed Arctic sea ice is likely to increase dramatically until the middle of this century regardless of the emissions scenario.Thereafter, it may decrease(or remain stable) if the Arctic warming crosses a threshold(or is extensively constrained). 展开更多
关键词 wintertime newly formed Arctic sea ice model democracy model weighting scheme model performance model independence
下载PDF
The Path to Growth and Maturity for Young Students: Embracing Independence and Self- Reliance
2
作者 Ruimin Chang Qin Zhao 《Journal of Contemporary Educational Research》 2024年第8期290-295,共6页
Young students are the future of our country and the hope of our nation.The healthy growth of young students must rely on independence and self-reliance.From the perspectives of family,society,and school,this article ... Young students are the future of our country and the hope of our nation.The healthy growth of young students must rely on independence and self-reliance.From the perspectives of family,society,and school,this article explores the cultivation of young students’spirit of independence and self-reliance,which should be grasped from three aspects:recognizing the situation,identifying the reasons,and taking effective measures. 展开更多
关键词 Young students SELF-RELIANCE independence PATH
下载PDF
Cosmology-Independent Photon Mass Limits from Localized Fast Radio Bursts by Using Artificial Neural Networks
3
作者 冉景遇 王宝 魏俊杰 《Chinese Physics Letters》 SCIE EI CAS CSCD 2024年第5期177-183,共7页
A hypothetical photon mass m_(γ) can produce a frequency-dependent vacuum dispersion of light, which leads to an additional time delay between photons with different frequencies when they propagate through a fixed di... A hypothetical photon mass m_(γ) can produce a frequency-dependent vacuum dispersion of light, which leads to an additional time delay between photons with different frequencies when they propagate through a fixed distance. The dispersion measure and redshift measurements of fast radio bursts(FRBs) have been widely used to constrain the rest mass of the photon. However, all current studies analyzed the effect of the frequency-dependent dispersion for massive photons in the standard ΛCDM cosmological context. In order to alleviate the circularity problem induced by the presumption of a specific cosmological model based on the fundamental postulate of the masslessness of photons, here we employ a new model-independent smoothing technique, artificial neural network(ANN), to reconstruct the Hubble parameter H(z) function from 34 cosmic-chronometer measurements.By combining observations of 32 well-localized FRBs and the H(z) function reconstructed by ANN, we obtain an upper limit of m_(γ) ≤ 3.5 × 10^(-51)kg, or equivalently m_(γ) ≤ 2.0 × 10^(-15)eV/c^(2)(m_(γ) ≤ 6.5 × 10^(-51)kg, or equivalently m_(γ) ≤ 3.6 × 10^(-15)eV/c_(2)) at the 1σ(2σ) confidence level. This is the first cosmology-independent photon mass limit derived from extragalactic sources. 展开更多
关键词 DISPERSION LIMIT independENT
下载PDF
A Constrained Local Neighborhood Approach for Efficient Markov Blanket Discovery in Undirected Independent Graphs
4
作者 Kun Liu Peiran Li +4 位作者 Yu Zhang JiaRen Ming Li Xianyu Wang Cong Li 《Computers, Materials & Continua》 SCIE EI 2024年第8期2535-2555,共21页
When learning the structure of a Bayesian network,the search space expands significantly as the network size and the number of nodes increase,leading to a noticeable decrease in algorithm efficiency.Traditional constr... When learning the structure of a Bayesian network,the search space expands significantly as the network size and the number of nodes increase,leading to a noticeable decrease in algorithm efficiency.Traditional constraint-based methods typically rely on the results of conditional independence tests.However,excessive reliance on these test results can lead to a series of problems,including increased computational complexity and inaccurate results,especially when dealing with large-scale networks where performance bottlenecks are particularly evident.To overcome these challenges,we propose a Markov blanket discovery algorithm based on constrained local neighborhoods for constructing undirected independence graphs.This method uses the Markov blanket discovery algorithm to refine the constraints in the initial search space,sets an appropriate constraint radius,thereby reducing the initial computational cost of the algorithm and effectively narrowing the initial solution range.Specifically,the method first determines the local neighborhood space to limit the search range,thereby reducing the number of possible graph structures that need to be considered.This process not only improves the accuracy of the search space constraints but also significantly reduces the number of conditional independence tests.By performing conditional independence tests within the local neighborhood of each node,the method avoids comprehensive tests across the entire network,greatly reducing computational complexity.At the same time,the setting of the constraint radius further improves computational efficiency while ensuring accuracy.Compared to other algorithms,this method can quickly and efficiently construct undirected independence graphs while maintaining high accuracy.Experimental simulation results show that,this method has significant advantages in obtaining the structure of undirected independence graphs,not only maintaining an accuracy of over 96%but also reducing the number of conditional independence tests by at least 50%.This significant performance improvement is due to the effective constraint on the search space and the fine control of computational costs. 展开更多
关键词 Bayesian network structure learning Markov blanket conditional independence
下载PDF
Origin of the Dashuigou independent tellurium deposit at Qinghai–Xizang Plateau: constraints from the light stable isotopes C, O, and H
5
作者 Jianzhao Yin Yuhong Chao +2 位作者 Haoyu Yin Hongyun Shi Shoupu Xiang 《Acta Geochimica》 EI CAS CSCD 2024年第2期385-398,共14页
By studying the light isotopic compositions of carbon,oxygen,and hydrogen,combined with previous research results on the ore-forming source of the deposit,the authors try to uncover its metallogenic origin.The δ^(18)... By studying the light isotopic compositions of carbon,oxygen,and hydrogen,combined with previous research results on the ore-forming source of the deposit,the authors try to uncover its metallogenic origin.The δ^(18)O and δ^(13)C isotope signatures of dolomite samples vary between 10.2 and 13.0‰,and between−7.2 and−5.2‰,respectively,implying that the carbon derives from the upper mantle.δD and δ^(18) O of quartz,biotite,and muscovite from diff erent ore veins of the deposit vary between−82 and−59‰,and between 11.6 and 12.4‰,respectively,implying that the metallogenic solutions are mainly magmatic.According to the relevant research results of many isotope geologists,the fractionation degree of hydrogen isotopes increases as the depth to the Earth’s core increases,and the more diff erentiated the hydrogen isotopes are,the lower their values will be.In other words,mantle-derived solutions can have extremely low hydrogen isotope values.This means that the δD‰ value−134 of the pyrrhotite sample numbered SD-34 in this article may indicate mantle-derived oreforming fl uid of the deposit.The formation of the Dashuigou tellurium deposit occurred between 91.71 and 80.19 Ma. 展开更多
关键词 Carbon oxygen and hydrogen isotopes ORIGIN independent tellurium deposit The Qinghai–Xizang Plateau
下载PDF
Are cities greener because of innovation?Independent innovation policy and green economic efficiency
6
作者 Zhuoji Zheng Xueqin Li +3 位作者 Mengjie Yu Yuan Li Xianfeng Han Yuping Yin 《Chinese Journal of Population,Resources and Environment》 2024年第2期118-126,共9页
The national independent innovation demonstration zone(NIIDZ)is an independent innovation policy that plays a crucial role in implementing strategies.Given the importance of the NIIDZ,this study uses panel data of 278... The national independent innovation demonstration zone(NIIDZ)is an independent innovation policy that plays a crucial role in implementing strategies.Given the importance of the NIIDZ,this study uses panel data of 278 prefecture-level cities in China from 2006 to 2020 and empirically examines the effect and internal mechanism of the NIIDZ on green economic efficiency(GEE)using the difference-in-difference model(DID).The results show that the NIIDZ effectively enhances the growth of GEE,and the results remain valid through several robustness tests,such as year-by-year propensity score matching.The transmission mechanism suggests that the NIIDZ indirectly drives GEE by accelerating scientific and technological investment,promoting talent concentration,and optimizing the industrial structure.Moreover,heterogeneity analysis reveals that the promotion effect of the NIIDZ on GEE is more prominent in the eastern region and high green development level areas.The study’s findings can serve as a reference for China to further utilize the policy effectiveness of the NIIDZ and accelerate the high-quality development of the green economy in the future. 展开更多
关键词 National innovation independent demonstration Zone(NIIDZ) Green economy efficiency(GEE) Difference-in-difference model(DID)
下载PDF
Study on Independent Supervision Function of Design Assurance System
7
作者 SUI Lijun MA Congyao WANG Jianyuan 《International Journal of Plant Engineering and Management》 2024年第3期185-192,共8页
The effective operation of a design assurance system cannot be achieved without the effective performance of the independent supervision function.As one of the core functions of the design assurance system,the purpose... The effective operation of a design assurance system cannot be achieved without the effective performance of the independent supervision function.As one of the core functions of the design assurance system,the purpose of the independent supervision function is to ensure that the system operates within the scope of procedures and manuals.At present,the function of independent supervision is a difficult and confusing issue for various original equipment manufacturers as well as suppliers,and there is an urgent requirement to put forward relevant requirements and form relevant methods.Based on the above mentioned objective,the basic requirements of the independent supervision function of design assurance system were studied,the problems and deficiencies in the organization,staffing,and methods existing in the current independent supervision function were analyzed,the improvement suggestions and measures for the performance of the independent supervision function from the aspects of the organization,staffing,procedures,and suppliers were put forward.The present work and conclusions provide guidance and direction for the effective operation of the design assurance system. 展开更多
关键词 design of assurance systems independent supervision functions system operation internal audits SUPPLIERS
下载PDF
Analysis of the Role of Problem-Based Independent Learning Model in Teaching Cerebral Ischemic Stroke First Aid in Emergency Medicine
8
作者 Hua Liu 《Journal of Contemporary Educational Research》 2024年第6期16-21,共6页
Objective:To analyze the effect of using a problem-based(PBL)independent learning model in teaching cerebral ischemic stroke(CIS)first aid in emergency medicine.Methods:90 interns in the emergency department of our ho... Objective:To analyze the effect of using a problem-based(PBL)independent learning model in teaching cerebral ischemic stroke(CIS)first aid in emergency medicine.Methods:90 interns in the emergency department of our hospital from May 2022 to May 2023 were selected for the study.They were divided into Group A(45,conventional teaching method)and Group B(45 cases,PBL independent learning model)by randomized numerical table method to compare the effects of the two groups.Results:The teaching effect indicators and student satisfaction scores in Group B were higher than those in Group A(P<0.05).Conclusion:The use of the PBL independent learning model in the teaching of CIS first aid can significantly improve the teaching effect and student satisfaction. 展开更多
关键词 Problem-based independent learning model Emergency medicine Ischemic stroke First aid teaching SATISFACTION
下载PDF
Quasi-χ~2 Distribution and the Independence of Wishart Distribution
9
作者 朱道元 赵胜利 《Journal of Southeast University(English Edition)》 EI CAS 2002年第2期173-176,共4页
In this paper, the authors generalize the definition of χ 2 distribution and introduce a quasi χ 2 distribution, and then prove several properties of it, find the necessary and sufficient conditions of i... In this paper, the authors generalize the definition of χ 2 distribution and introduce a quasi χ 2 distribution, and then prove several properties of it, find the necessary and sufficient conditions of independence about multivariate normal distributions, matrix normal distributions and two parts of the Wishart distribution. 展开更多
关键词 quasi χ 2 Wishart distribution independence
下载PDF
Independence Test of Wheat Head Blight Infection
10
作者 夏海峰 《Plant Diseases and Pests》 CAS 2010年第5期38-39,53,共3页
The relationship between wheat varieties and occurrence of head blight was discussed, the independence test was carried out by using contingency table.
关键词 Hypothesis testing SAMPLE independENT
下载PDF
The Use of Field Dependence/Independence in Language Acquisition
11
作者 操龙升 《海外英语》 2012年第20期114-115,共2页
Field dependence/independence in Language Acquisition are discussed by many language learners.In this article,we will mainly focus on talking about the cognitive style,including the concept of Field-dependence/indepen... Field dependence/independence in Language Acquisition are discussed by many language learners.In this article,we will mainly focus on talking about the cognitive style,including the concept of Field-dependence/independence,their character istics and differences and functions in language acquisition. 展开更多
关键词 FIELD dependence/independence LANGUAGE ACQUISITION
下载PDF
NONNULL DISTRIBUTION OF THE LIKELIHOOD RATIO CRITERION FOR TESTING THE EQUALITY OF DIAGONAL BLOCKS WITH BLOCKWISE INDEPENDENCE 被引量:5
12
作者 A. K. Gupta C. C. Chao(Bowling Green State University Bowling Green, OH 43403-0221 C. C. ChaoJacksonville State Univesity Jacksonville, AL 36265) 《Acta Mathematica Scientia》 SCIE CSCD 1994年第2期195-203,共9页
In this paper, the nonnull moments and the distributions of the likelihood ratio criterion for testing the equality of diagonal blocks with blockwise independence under certain alternatives have derived.
关键词 RATIO BLOCKWISE CRITERION DIAGONAL DISTRIBUTION EQUALITY FOR independence LIKELIHOOD NONNULL
下载PDF
Sub-independence-spaces 被引量:2
13
作者 MAO Huat WANG Gang 《Chinese Quarterly Journal of Mathematics》 CSCD 2010年第2期293-299,共7页
Cleverly using the relation of independence spaces and B-matroids, this paper firstly deals with the properties of the closure operator of an independence space, followed by presenting the definitions and solving some... Cleverly using the relation of independence spaces and B-matroids, this paper firstly deals with the properties of the closure operator of an independence space, followed by presenting the definitions and solving some relative properties for the sub-independence spaces of an independence space with the help of circuits. 展开更多
关键词 CIRCUIT sub-independence-space independence space closure operator
下载PDF
CONSISTENCY BETWEEN INDEPENDENCE THEOREMS AND GENERALIZED SELF-CONSISTENT METHOD 被引量:1
14
作者 杜丹旭 郑泉水 高蕴昕 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 1997年第4期355-365,共11页
Recently Zheng & Hwang established a series of independence theorems concerning with planar effective elastic properties. It is manifested that the estimation of the effective elastic properties of microcracked so... Recently Zheng & Hwang established a series of independence theorems concerning with planar effective elastic properties. It is manifested that the estimation of the effective elastic properties of microcracked solids through the generalized self-consistent method (GSCM) contradicts with these independence theorems. In this paper it is shown that such contradiction is actually caused by the approximate algorithm adopted, while the exact solution of GSCM is consistent with these rigorously established independence theorems. Since only an approximate algorithm in GCSM is available in dealing with problems involving non-circular inclusions or holes, an intrinsic GSCM is proposed, which can be performed based on an approximate algorithm and the corresponding estimations are consistent with the independence theorems. 展开更多
关键词 intrinsic Generalised Self-Consistent Method independence energy equivalence effective properties
下载PDF
On the connotation, challenge and significance of China’s “energy independence” strategy 被引量:7
15
作者 ZOU Caineng PAN Songqi ZHAO Qun 《Petroleum Exploration and Development》 2020年第2期449-462,共14页
The world’s energy is in the "third major transformation period" from fossil energy to new energy, and all countries in the world have formulated energy development strategies. Through advanced deployment, ... The world’s energy is in the "third major transformation period" from fossil energy to new energy, and all countries in the world have formulated energy development strategies. Through advanced deployment, the United States is about to achieve "energy independence" relying on "unconventional oil and gas revolution". China’s energy development is faced with four challenges:(1) The population base and economic development scale determine the "totally huge amount" of energy consumption;(2) the "coal rich but oil and gas insufficient" resource structure determines the "unclean" energy consuming structure;(3) the increasing dependence on imported oil and gas determines the "unsafe" energy supply;and(4) the unconventional oil and gas endowment makes it impossible to achieve energy independence by copying the American model. From the perspective of the world energy trend and the unique situation of China’s energy, we put forward a "three-step" strategy for China to achieve "energy independence": From 2020 to 2035, "energy supply security" will be addressed by "cleaning coal, stabilizing oil and gas production and vigorously developing new alternative energy";from 2035 to 2050, the vision of "production independence" will be realized by relying on "domestic production and overseas oil and gas mining rights";from 2050 to 2100, "intelligent energy and new energy" will help China realize "energy independence". The two important signs of China’s "energy independence" are that domestic production accounts for more than 90% of the domestic consumption and clean energy production accounts for more than 70%, and energy security realizes "independence and self-control" and "long-term security". The strategic significance of "energy independence" is to ensure national energy security, drive the development of relevant major industries, achieve energy management reform, and implement the environmental protection goal of zero carbon emissions. The "energy independence" of China is a strategic mission, it might be fulfilled in the future with the growth of the state’s power, even when the domestic energy production does not catch up with the domestic consumption. Perhaps the world’s new technological revolution will exceed expectations, and China’s "energy independence" dream will eventually come true. 展开更多
关键词 energy independence energy revolution intelligent energy COAL unconventional oil and gas new energy energy long march
下载PDF
A View on Independence of Grammar——Extracts from Syntactic Structures
16
作者 马昱 《英语广场(学术研究)》 2012年第6期37-38,共2页
According to Chomsky,the grammar of Language is a device that generates all of the grammatical sequences of Language and none of the ungrammatical ones.However,as the foundation of Universal Grammar,independence of gr... According to Chomsky,the grammar of Language is a device that generates all of the grammatical sequences of Language and none of the ungrammatical ones.However,as the foundation of Universal Grammar,independence of grammar is strongly criticized by many other linguists.This paper aims at reviewing the literature and illustrating different ideas towards Universal Grammar. 展开更多
关键词 Universal Grammar independence of grammar CHOMSKY
下载PDF
The Criterion of weighting the independence of non-executive directors
17
作者 师怡 《商情》 2008年第7期47-,54,共2页
Non-executive directors are now very well established in Chinese business. The uniform and final criterion of weighting the independence of non-executive directors is not available. It will be valuable to draw an anal... Non-executive directors are now very well established in Chinese business. The uniform and final criterion of weighting the independence of non-executive directors is not available. It will be valuable to draw an analogy with the criterion of weighting the independence of non-executive directors in the UK, where over a dozen different criterions are applied. 展开更多
关键词 non-executive directors the independence of non-executive directors CRITERION of weighting the independence
下载PDF
Upholding Peace, Development, Independence and Inclusiveness and Renewing the Firm Commitment to Open Regionalism 被引量:1
18
作者 Wang Yi 《China International Studies》 2022年第4期5-14,共10页
Over the past 10 years, China-ASEAN relations have entered the fast lane and made accelerating progress, as countries in the region adhere to open regionalism, respect and appreciate the diversities among members, and... Over the past 10 years, China-ASEAN relations have entered the fast lane and made accelerating progress, as countries in the region adhere to open regionalism, respect and appreciate the diversities among members, and uphold and practice the principle of voluntarism. China is ready to join hands with ASEAN members and other regional countries to adhere to the vision of peace, development, independence and inclusiveness, firmly uphold open regionalism, and constantly add new dimensions to open regionalism. 展开更多
关键词 independence PEACE dimensions
下载PDF
LINEAR INDEPENDENCE OF THE INTEGER TRANS-LATES OF COMPACTLY SUPPORTED DISTRIBU-TIONS AND REFINABLE VECTORS
19
作者 Sun QiyuDept. of Math.,National University of Singapore,10 Kent Ridge Crescent,Singapore 119260,Singapore. 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2001年第4期381-396,共16页
In this paper,the global and local linear independence of any compactly supported distributions by using time domain spaces,and of refinable vectors by invariant linear spaces are investigated.
关键词 Global linear independence local linear independence refinable vector invariant space.
下载PDF
The Researches on Path Independence Problem
20
作者 Luo Yunfeng Xiao Renbin & Zhu Mingfu(Institute of Systems Engineering, Huazhong University of Science and Technology,Wuhan 430074, P. R. China) 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1998年第2期19-22,共4页
Rationality condition is imposed in Arrow's General Possibility Theorem in order for social choice to be independent of the path of choice. In this Paper, emphasis is laid on the analysis of the relevance of path ... Rationality condition is imposed in Arrow's General Possibility Theorem in order for social choice to be independent of the path of choice. In this Paper, emphasis is laid on the analysis of the relevance of path independence and rationality condition. Two kinds of Path independence, i.e., Plott's path independence and Bandyopadhyay's sequential path independence, are shown, and their meanings with respect to the problem are investigated. 展开更多
关键词 Social choice Rationality condition Path independence Sequential path independence
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部