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Approximation Schemes for the 3-Partitioning Problems
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作者 Jianbo Li Honglin Ding 《Communications and Network》 2013年第1期90-95,共6页
The 3-partitioning problem is to decide whether a given multiset of nonnegative integers can be partitioned into triples that all have the same sum. It is considerably used to prove the strong NP-hardness of many sche... The 3-partitioning problem is to decide whether a given multiset of nonnegative integers can be partitioned into triples that all have the same sum. It is considerably used to prove the strong NP-hardness of many scheduling problems. In this paper, we consider four optimization versions of the 3-partitioning problem, and then present four polynomial time approximation schemes for these problems. 展开更多
关键词 3-partitioning problem APPROXIMATION SCHEME
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中高职“3+2”衔接教育及存在的问题、原因与对策
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作者 雷建龙 胡燕妮 +1 位作者 黄铂 冯雪姣 《武汉船舶职业技术学院学报》 2024年第2期41-46,共6页
通过对湖北省及全国部分地区中高职“3+2”衔接技能人才分段培养的调研,梳理人才培养过程中存在的问题及主要原因。一是高职阶段学生学习动力不足,学生管理难度大;原因有中职段管理不严,学习无压力,及教学设计存在问题;二是课程设置存... 通过对湖北省及全国部分地区中高职“3+2”衔接技能人才分段培养的调研,梳理人才培养过程中存在的问题及主要原因。一是高职阶段学生学习动力不足,学生管理难度大;原因有中职段管理不严,学习无压力,及教学设计存在问题;二是课程设置存在脱节与重叠现象;问题原因是标准未严格执行,并且中高职校缺乏沟通;三是存在衔接口径不匹配现象;原因在于缺乏专业设置标准及监督。针对问题提出了相应的对策建议。一是要建立统一的专业衔接标准、专业教学标准,加强标准执行情况的检查力度;二是要改革“3+2”转段考核的方式,加强中职学生平时成绩的要求与管理;三是加强中高职的沟通与交流;四是延伸中高职衔接为中高本衔接。 展开更多
关键词 中高职 3+2” 衔接教育 问题与原因 对策
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三孩政策下0—3岁婴幼儿托育服务存在的问题与对策
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作者 王婉纯 《黑龙江教师发展学院学报》 2024年第6期146-152,共7页
2021年三孩政策在全国范围内正式实施,使得托育服务成为民生刚性需求。随着托育服务事业的迅速发展,其面临的一系列困境值得关注。从托育服务的四大主体政府、社会、教师和家庭四方面分析当前0—3岁婴幼儿托育服务存在的问题。在此基础... 2021年三孩政策在全国范围内正式实施,使得托育服务成为民生刚性需求。随着托育服务事业的迅速发展,其面临的一系列困境值得关注。从托育服务的四大主体政府、社会、教师和家庭四方面分析当前0—3岁婴幼儿托育服务存在的问题。在此基础上,提出相应的优化对策,即完善政策体系与托育制度,持续加大政府扶持力度,重点发展普惠性托育服务,提高托育服务质量,加强托育人员队伍建设,发展特色早教课程,创新社区托育模式等,以期促进0—3岁婴幼儿健康成长。 展开更多
关键词 三孩政策 0—3岁婴幼儿 托育服务 问题 优化对策
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Why is the Danger Cylinder Dangerous in the P3P Problem? 被引量:5
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作者 ZHANG Cai-Xia HU Zhan-Yi 《自动化学报》 EI CSCD 北大核心 2006年第4期504-511,共8页
The PnP problem is a widely used technique for pose determination in computer vision community,and finding out geometric conditions of multiple solutions is the ultimate and most desirable goal of the multi-solution a... The PnP problem is a widely used technique for pose determination in computer vision community,and finding out geometric conditions of multiple solutions is the ultimate and most desirable goal of the multi-solution analysis,which is also a key research issue of the problem.In this paper,we prove that given 3 control points,if the camera's optical center lies on the so-called“danger cylinder”and is enough far from the supporting plane of control points,the corresponding P3P problem must have 3 positive solutions.This result can bring some new insights into a better understanding of the multi-solution problem.For example,it is shown in the literature that the solution of the P3P problem is instable if the optical center lies on this danger cylinder,we think such occurrence of triple-solution is the primary source of this instability. 展开更多
关键词 The P3P problem the danger cylinder instability of solution
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Key Problems of Cold Power Spinning of Ti-15-3 Alloy 被引量:1
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作者 Debin SHAN Yan LU and Ping LI School of Materials Science and Engineering, Harbin institute of Thchnology, Harbin 150001, China Yi XU Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110015, China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2001年第1期125-126,共2页
The key problems of cold power spinning of Ti-15-3 alloy are studied. Reasonable billet preparation methods are presented to improve crystal structure and avoid crack of billet. Influences of original wall thickness, ... The key problems of cold power spinning of Ti-15-3 alloy are studied. Reasonable billet preparation methods are presented to improve crystal structure and avoid crack of billet. Influences of original wall thickness, reduction rate and feed rate on expanding in diameter are analyzed and some methods to prevent expanding in diameter are given. 展开更多
关键词 TI Key problems of Cold Power Spinning of Ti-15-3 Alloy
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An adiabatic quantum optimization for exact cover 3 problem
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作者 张映玉 许丽莉 李俊青 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第3期139-141,共3页
A perturbation method is applied to study the structure of the ground state of the adiabatic quantum optimization for the exact cover 3 problem. It is found that the instantaneous ground state near the end of the evol... A perturbation method is applied to study the structure of the ground state of the adiabatic quantum optimization for the exact cover 3 problem. It is found that the instantaneous ground state near the end of the evolution is mainly composed of the eigenstates of the problem Hamiltonian, which are Hamming close to the solution state. And the instantaneous ground state immediately after the starting is mainly formed of low energy eigenstates of the problem Hamiltonian. These results are then applied to estimate the minimum gap for a special case. 展开更多
关键词 adiabatic quantum optimization exact cover 3 problem perturbation expansion
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On the Solution to the Separated Equation in the 3-Particle Calogero-Moser Problem
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作者 Natalia Inozemtseva Jaroslav Dittrich Vladimir Inozemtsev 《Advances in Pure Mathematics》 2018年第3期266-271,共6页
We propose the exact solution of the equation in separated variable which appears in the process of constructing solutions to the quantum Calogero-Moser three-particle problem with elliptic two-particle potential . Th... We propose the exact solution of the equation in separated variable which appears in the process of constructing solutions to the quantum Calogero-Moser three-particle problem with elliptic two-particle potential . This solution is found for special values of coupling constants . It can be used for solving three-particle Calogero-Moser problem under the appropriate boundary conditions. 展开更多
关键词 Calogero-Moser Model 3-Particle problem SEPARATION of VARIABLES
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SCORE SETS IN ORIENTED 3-PARTITE GRAPHS
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作者 S.Pirzada Merajuddin T.A.Naikoo 《Analysis in Theory and Applications》 2007年第4期363-374,共12页
Abstract. Let D (U, V, W) be an oriented 3-partite graph with | U | = p, |V| = q and |W | = r. For any vertex x in D(U,V,W), let dx^+ and dui^- be the outdegree and indegree ofx respectively. Define aui (o... Abstract. Let D (U, V, W) be an oriented 3-partite graph with | U | = p, |V| = q and |W | = r. For any vertex x in D(U,V,W), let dx^+ and dui^- be the outdegree and indegree ofx respectively. Define aui (or simply ai) = q + r + dui^+ - dui^-, bvj (or simply b j) = p + r + d^+vj - d^-vj and cwk (or simply ck) =p + q + dwk^+ -dwk^- as the scores of ui in U,vj in V and wk in W respectively. The set A of distinct scores of the vertices of D(U, V, W) is called its score set. In this paper, we prove that if a1 is a non-negative integer, ai(2 ≤ i ≤ n - 1) are even positive integers and an is any positive integer, then for n 〉 3, there exists an oriented 3-partite graph with the score set A ={a1,Σ2i=1 ai,…,Σni=1 ai}, except when A = {0, 2, 3}. Some more results for score sets in oriented 3-partite graphs are obtained. 展开更多
关键词 oriented graph oriented 3-partite graph tournament score set
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Structure Formation and Non Linear Electrodynamics with Attendant Changes in Gravitational Potential and Its Relationship to the 3 Body Problem
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作者 Andrew Walcott Beckwith 《Journal of High Energy Physics, Gravitation and Cosmology》 2018年第4期779-786,共8页
We find that having the scale factor close to zero due to a given magnetic field value, an early universe magnetic field affects how we would interpret Mukhanov’s chapter on “self reproduction of the universe”. We ... We find that having the scale factor close to zero due to a given magnetic field value, an early universe magnetic field affects how we would interpret Mukhanov’s chapter on “self reproduction of the universe”. We extend such arguments, and refer to the possibility of modified gravity. We hope that some of the issues raised by Kobayashi and Seto as to allowed inflation models may be addressed, once further refinement of these preliminary results commences. We close with statements as to the value of α in a gravitational potential proportional to r?α and how this adjustment affects the 3 body problem. 展开更多
关键词 INFLATION Modified GRAVITY 3 BODY problem
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The Analysis of Convergence for the 3<i>X</i>+ 1 Problem and Crandall Conjecture for the a<i>X</i>+ 1 Problem
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作者 Zuojun Hu 《Advances in Pure Mathematics》 2021年第5期400-407,共8页
The 3<em>X</em> + 1 problem (Collatz conjecture) has been proposed for many years, however no major breakthrough has been made so far. As we know, the Crandall conjecture is a well-known generalization of ... The 3<em>X</em> + 1 problem (Collatz conjecture) has been proposed for many years, however no major breakthrough has been made so far. As we know, the Crandall conjecture is a well-known generalization of the 3<em>X</em> + 1 problem. It is worth noting that, both conjectures are infamous for their simplicity in stating but intractability in solving. In this paper, I aim to provide a clear explanation about the reason why these two problems are difficult to handle and have very different characteristics on convergence of the series via creatively applying the probability theory and global expectancy value <em>E</em>(<em>n</em>) of energy contraction index. The corresponding convergence analysis explicitly shows that <em>a</em> = 3 leads to a difficult problem, while <em>a</em> > 3 leads to a divergent series. To the best of my knowledge, this is the first work to point out the difference between these cases. The corresponding results not only propose a new angle to analyze the 3<em>X</em> + 1 problem, but also shed some light on the future research. 展开更多
关键词 3X + 1 problem Crandall Conjecture Energy Method Expectancy Theory
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On the Change Rule of 3x + 1 Problem
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作者 Ke Li 《Journal of Applied Mathematics and Physics》 2022年第3期850-864,共15页
This article introduces a change rule of 3x + 1 problem (Collatz conjecture), it’s named LiKe’s Rule. It’s a map of 3x + 1 problem, and details the path of each step of the change: For any positive integer, change ... This article introduces a change rule of 3x + 1 problem (Collatz conjecture), it’s named LiKe’s Rule. It’s a map of 3x + 1 problem, and details the path of each step of the change: For any positive integer, change by the Collatz conjecture. 1) This positive integer will change to an odd number;2) The odd number must change to a number of LiKe’s second sequence {3<sup>n</sup> – 1| n ∈ Z<sup>+</sup>};3) Then this 3<sup>n</sup> - 1 will change to a smaller 3<sup>n </sup>– 1 and gradually decrease to 8 (that is 3<sup>2</sup> - 1) then back to 1 in the end. If we can determine each step, the Collatz conjecture will be true. This is certainly more valuable than 2<sup>n</sup> (it might even explain 2<sup>n</sup>). And to illustrate the importance of this rule, introduced some important funny corollaries related to it. 展开更多
关键词 3x +1 problem Collatz-problem Collatz Conjecture LiKe’s Rule Number Theory
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GENERALIZED UPWIND SCHEME WITH FRACTIONAL STEPS FOR 3-D PROBLEM OF CONVECTION DOMINATING GROUNDWATER TRANSPORT
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作者 姚磊华 《Journal of Coal Science & Engineering(China)》 1997年第2期68-72,共5页
A generalized upwind scheme with fractional steps for 3-D mathematical models of convection dominating groundwater quality is suggested. The mass transport equation is split into a convection equation and a dispersive... A generalized upwind scheme with fractional steps for 3-D mathematical models of convection dominating groundwater quality is suggested. The mass transport equation is split into a convection equation and a dispersive equation. The generalized upwind scheme is used to solve the convection equation and the finite element method is used to compute the dispersive equation.These procedures which not only overcome the phenomenon of the negative concentration and numerical dispersion appear frequently with normal FEM or FDM to solve models of convection dominating groundwater transport but also avoid the step for computing each node velocity give a more suitable method to calculate the concentrations of the well points. 展开更多
关键词 地下水 运移模型 水质模型 有限元分析
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The Simplest Possible Fully Correct Solution of the Clay Millennium Problem about P vs. NP. A Simple Proof That P ≠ NP = EXPTIME
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作者 Konstantinos E. Kyritsis 《Journal of Computer and Communications》 2023年第8期181-194,共14页
In the current paper, I present probably the simplest possible abstract formal proof that P ≠ NP, and NP = EXPTIME, in the context of the standard mathematical set theory of computational complexity and deterministic... In the current paper, I present probably the simplest possible abstract formal proof that P ≠ NP, and NP = EXPTIME, in the context of the standard mathematical set theory of computational complexity and deterministic Turing machines. My previous publications about the solution of the P vs. NP with the same result NP = EXPTIME, to be fully correct and understandable need the Lemma 4.1 and its proof of the current paper. The arguments of the current paper in order to prove NP = EXPTME are even simpler than in my previous publications. The strategy to solve the P vs. NP problem in the current paper (and in my previous publications) is by starting with an EXPTIME-complete language (problem) and proving that it has a re-formulation as an NP-class language, thus NP = EXPTIME. The main reason that the scientific community has missed so far such a simple proof, is because of two factors 1) It has been tried extensively but in vain to simplify the solutions of NP-complete problems from exponential time algorithms to polynomial time algorithms (which would be a good strategy only if P = NP) 2) It is believed that the complexity class NP is strictly a subclass to the complexity class EXPTIME (in spite the fact that any known solution to any of the NP-complete problems is not less than exponential). The simplicity of the current solution would have been missed if 2) was to be believed true. So far the majority of the relevant scientific community has considered this famous problem not yet solved. The present results definitely solve the 3rd Clay Millennium Problem about P versus NP in a simple, abstract and transparent way that the general scientific community, but also the experts of the area, can follow, understand and therefore become able to accept. 展开更多
关键词 3rd Clay Millennium problem EXPTIME-Complete problems NP-Complexity P-Complexity
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Enhancing Numeracy Skills of Grade 3 Students Through Authentic Performance Tasks
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作者 Glendell De Guzman Celemin 《Journal of Contemporary Educational Research》 2023年第9期59-66,共8页
Numeracy is the capacity to use mathematical ideas in all facets of life.It involves activities such as adding and subtracting numbers,counting,number recognition,solving number problems involving various operations,s... Numeracy is the capacity to use mathematical ideas in all facets of life.It involves activities such as adding and subtracting numbers,counting,number recognition,solving number problems involving various operations,sorting,observing,identifying,and establishing patterns.It is one of the fundamental skills that students should have mastered by the end of their primary schooling.With the notable importance of mastery of numeracy skills,low achievement and performance of the learners were observed in this aspect.This study aimed in enhancing the numeracy skills of Grade 3 learners through authentic performance tasks.The variable in numeracy skills includes the four fundamental operations and problem solving.The quasi-experimental design was utilized wherein purposive sampling or non-randomized sampling was used.In this study,33 Grade 3 learners of Rizal Elementary School were selected to participate in the tests.Pre-test and post-test crafted by the teacher were the main instrument in the study.The result revealed that in the pre-test the learners obtained a mean percentage score(MPS)of 38.20%in four fundamental operations,which implied a non-numerate level.While in terms of problem solving,the learners obtained a MPS of 20.60%which is also in the non-numerate level.It has a grand mean of 29.40%with an interpretation of non-numerate level.In the post-test,it was observed that four fundamental operations have a MPS of 81.10%which is in average numerate level,while problem solving has a MPS of 76.30%with a grand mean of 78.70%with an interpretation of average numerate level.This implied that there is a significant difference between the pre-test and post-test in the four fundamental operations and problem solving.Thus,it can be concluded that the application of authentic performance tasks was effective to bridge the gap on numeracy skills. 展开更多
关键词 Numeracy skills Authentic performance tasks Four fundamental operations problem solving Grade 3 learners
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遗传算法和3-opt结合求解带有能力约束的VRP 被引量:26
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作者 张涛 王梦光 《东北大学学报(自然科学版)》 EI CAS CSCD 北大核心 1999年第3期254-256,共3页
描述了带有能力约束的车辆路径问题(VRP),在预先不固定车辆数的情况下,把聚类和排序有机地结合起来,并用遗传算法和3opt算法相结合的混合算法对问题进行求解,实验结果表明算法获得的最好解、平均负荷率和计算成本都比较... 描述了带有能力约束的车辆路径问题(VRP),在预先不固定车辆数的情况下,把聚类和排序有机地结合起来,并用遗传算法和3opt算法相结合的混合算法对问题进行求解,实验结果表明算法获得的最好解、平均负荷率和计算成本都比较令人满意· 展开更多
关键词 车辆路径问题 遗传算法 3-opt算法 能力约束 VRP
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一种求解3-SAT问题的新方法 被引量:6
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作者 贺毅朝 王彦祺 寇应展 《计算机工程与应用》 CSCD 北大核心 2006年第16期70-72,共3页
可满足性问题(SatisfiabilityProblem,SAT)是计算科学的典型问题之一,目前有DP算法、SAT1.3算法和遗传算法等多种求解方法。文章根据Kennedy和Eberhart提出的二进制粒子群优化算法(BinaryParticleSwarmOptimizers),基于局部随机搜索策略... 可满足性问题(SatisfiabilityProblem,SAT)是计算科学的典型问题之一,目前有DP算法、SAT1.3算法和遗传算法等多种求解方法。文章根据Kennedy和Eberhart提出的二进制粒子群优化算法(BinaryParticleSwarmOptimizers),基于局部随机搜索策略,给出了一种求解3-SAT问题的新方法:基于局部随机搜索的改进二进制粒子群优化算法(ModifedBinaryParticleSwarmOptimizersBasedonlocalstochasticsearch,简称MBPSO)。数值实验表明,对于随机产生的3-SAT问题测试实例,该算法是一种高效实用的新方法。 展开更多
关键词 3-SAT问题 合取范式 PSO算法 局部搜索
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图3-着色问题的O(2^n)链数DNA计算机算法 被引量:2
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作者 李肯立 周旭 许进 《电子学报》 EI CAS CSCD 北大核心 2008年第11期2096-2101,共6页
随着DNA计算的不断发展,如何克服穷举算法带来的指数爆炸问题已成为DNA计算领域的重要研究目标之一.为减少图3-着色问题DNA计算机算法中的DNA链数,本文将Adleman-Lipton模型生物操作与粘贴模型解空间相结合的DNA计算模型进行扩展,通过... 随着DNA计算的不断发展,如何克服穷举算法带来的指数爆炸问题已成为DNA计算领域的重要研究目标之一.为减少图3-着色问题DNA计算机算法中的DNA链数,本文将Adleman-Lipton模型生物操作与粘贴模型解空间相结合的DNA计算模型进行扩展,通过设计顶点着色器、稀疏图/稠密图搜索器,提出一种用于求解图3-着色问题的DNA计算模型与算法.将本算法与同类算法对比分析表明:本算法在保持多项式操作时间的条件下,将求解n个顶点的图3-着色问题所需DNA分子链数从O(3n)减少至O(2n),改进了3-着色问题同类文献的研究结果. 展开更多
关键词 DNA超级计算 3-着色问题 剪枝策略 NP完全问题
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以母亲为中心促进儿童早期发展对2~3岁儿童行为的影响 被引量:4
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作者 黄东明 陈海燕 +5 位作者 杨孜 曾冠 李步梅 卓慕春 林迤逦 施玉麒 《中国儿童保健杂志》 CAS 2005年第6期484-486,共3页
[目的]探讨以母亲为中心促进儿童早期发展对2~3岁儿童行为方式和行为偏离的影响.[方法]选择中山市某社区内0~1岁儿童及其母亲为研究对象,实施为期至少1.5年、以母亲为中心的促进儿童早期发展干预活动.活动前后分别以现场询问的方式填... [目的]探讨以母亲为中心促进儿童早期发展对2~3岁儿童行为方式和行为偏离的影响.[方法]选择中山市某社区内0~1岁儿童及其母亲为研究对象,实施为期至少1.5年、以母亲为中心的促进儿童早期发展干预活动.活动前后分别以现场询问的方式填写<Aachenbach 2~3岁儿童行为调查表(家长问卷)>(CBCL),比较两组儿童CBCL的分析结果.[结果]对照组83名儿童的行为偏离发生率为68.7%(57/83);观察组91名儿童的行为偏离发生率为36.3%(33/91),两组比较差异有非常显著性(χ2=18.261,P<0.001).观察组各因子的得分均低于对照组,其中攻击、躯体陈述、忧郁和破坏4个因子的得分差异有显著性(P<0.05).[结论]建立'医生-母亲-儿童'的新型儿童保健模式,开展以母亲为中心促进儿童早期发展的活动可以明显减少2~3岁儿童行为偏离的发生. 展开更多
关键词 早期发展 行为偏离 2~3岁儿童
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植物种群-3/2幂自疏定律假设的点评 被引量:3
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作者 王仁忠 方林 +2 位作者 卢文祥 姜世成 王平 《东北师大学报(自然科学版)》 CAS CSCD 1998年第4期58-62,共5页
通过对国外大量研究报道的综合分析,详细阐述了-3/2幂自疏定律假设的概念、表达式、发展及存在的问题,旨在澄清对植物种群-3/2幂自疏定律假设的认识,推动我国植物种群密度制约机制研究的发展.
关键词 植物种群 自疏定律假设 种群动态 种群密度
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土壤中Al^(3+)对人参的为害 被引量:10
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作者 赵曰丰 李晓明 《特产研究》 1998年第3期38-42,共5页
论述了Al3+为土壤致酸阳离子,土壤白浆化过程可提供较多的Al3+、Fe2+;Al3+与人参红皮病、烧须、锈腐病发生及老参地的形成均有密切关系。
关键词 人参 AL^3+ 老参地 土壤 人参红皮病 烧须
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