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水稻开颖机理的探讨——Ⅲ.浆片的结构及其在开颖过程中内含物的变化 被引量:44
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作者 王忠 顾蕴洁 高煜珠 《作物学报》 CAS CSCD 北大核心 1991年第2期96-101,共6页
着生在小穗轴上的一对浆片是由许多大型薄壁细胞和分布均匀的若干条与小穗轴维管束相连的小维管束组成。每一浆片中小维管束数目因品种不同而异,一般含有15—20条。每一小维管束中具有1—5列导管,2—4列筛管和10个左右的小型薄壁细胞。... 着生在小穗轴上的一对浆片是由许多大型薄壁细胞和分布均匀的若干条与小穗轴维管束相连的小维管束组成。每一浆片中小维管束数目因品种不同而异,一般含有15—20条。每一小维管束中具有1—5列导管,2—4列筛管和10个左右的小型薄壁细胞。小型薄壁细胞的细胞质浓,细胞器多,富含线粒体。不管是大型的还是小型的薄壁细胞之间的胞间连丝都很丰富。这些结构特点可为颖花在开闭过程中,浆片的快速吸水失水以及物质的迅速转运提供通道和能量。浆片中含有淀粉酶。开颖时浆片的干物重及可溶性糖含量均有所增加。可溶性糖除来自淀粉水解外,还可能来自小穗轴的输入。我们认为,水稻的开颖运动主要是由浆片的渗透压所调节的水势变化而引起的;而闭颖过程则受小穗轴控制。切除小穗轴的颖花因浆片内水分不能外运而影响闭颖。 展开更多
关键词 水稻 开花 浆片 外颖 小穗轴
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On Decomposition Theorem of normalized biholomorphic convex mappings in Reinhardt domains 被引量:30
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作者 张文俊 刘太顺 《Science China Mathematics》 SCIE 2003年第1期94-106,共13页
The construction of normalized biholomorphic convex mappings in the Reinhardt domain $D_p = \{ (z_1 ,z_2 , \cdots ,z_n ) \in \mathbb{C}^n :\left| {z_1 } \right|^{p_1 } + \left| {z_2 } \right|^{p_2 } + \cdots + \left| ... The construction of normalized biholomorphic convex mappings in the Reinhardt domain $D_p = \{ (z_1 ,z_2 , \cdots ,z_n ) \in \mathbb{C}^n :\left| {z_1 } \right|^{p_1 } + \left| {z_2 } \right|^{p_2 } + \cdots + \left| {z_n } \right|^{p_n } < 1\} $ , p j > 2, j = 1,2,?, n) of ? n is discussed. The authors set up a Decomposition Theorem for such mappings. As a special case, it is proved that, for each such mapping f, the first k-terms of the homogeneous expansion of its j-th component f j , j = 1, 2, ?, n, depends only on z j , where k is the number that satisfies k < min {p 1, p 2,?, p n ≤ k + 1. When p1,p2, ... ,pn → ∞ , this derives the Decomposition Theorem of normalized biholomorphic convex mappings in the polydisc which was gotten by T.J. Suffridge in 1970. 展开更多
关键词 Reinhardt domain biholomorphic convex mapping Schwarz lemma Schwarz lemma
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中国学习者英语口语词汇量及常用词汇研究——基于英语口语语料库的词目研究 被引量:24
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作者 甄凤超 《解放军外国语学院学报》 北大核心 2005年第5期38-42,共5页
本研究比较COLSEC、BNC(口语部分)和ICE(口语部分)三个口语语料库中词目覆盖率及常用词目,目的是分析中国学习者考试环境下会话词汇量及掌握常用词汇的情况。统计结果显示,中国学习者英语会话词目数量较少,词目覆盖率大,某些常用词目被... 本研究比较COLSEC、BNC(口语部分)和ICE(口语部分)三个口语语料库中词目覆盖率及常用词目,目的是分析中国学习者考试环境下会话词汇量及掌握常用词汇的情况。统计结果显示,中国学习者英语会话词目数量较少,词目覆盖率大,某些常用词目被高频使用。此外,学习者并没有完全掌握日常英语会话所需的常用词目,其会话缺乏足够的交互性。因此,我们应当在英语口语教学中继续加强常用词汇的教学。 展开更多
关键词 口语语料库 词目 覆盖率
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BEAK-SHAPED GRAIN 1/TRIANGULAR HULL 1,a DUF640 gene,is associated with grain shape,size and weight in rice 被引量:21
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作者 YAN DaWei ZHOU Ya +3 位作者 YE ShengHai ZENG LongJun ZHANG XiaoMing HE ZuHua 《Science China(Life Sciences)》 SCIE CAS 2013年第3期275-283,共9页
Grain shape and size both determine grain weight and therefore crop yield. However, the molecular mechanisms controlling grain shape and size are still largely unknown. Here, we isolated a rice mutant, beak-shaped gra... Grain shape and size both determine grain weight and therefore crop yield. However, the molecular mechanisms controlling grain shape and size are still largely unknown. Here, we isolated a rice mutant, beak-shaped grain1 (bsgl), which produced beak-shaped grains of decreased width, thickness and weight with a loosely interlocked lemma and palea that were unable to close tightly. Starch granules were also irregularly packaged in the bsgl grains. Consistent with the lemma and palea shapes, the outer parenchyma cell layers of these bsgl tissues developed fewer cells with decreased size. Map-based cloning revealed that BSG1 encoded a DUF640 domain protein, TRIANGULAR HULL 1, of unknown function. Quantitative PCR and GUS fusion reporter assays showed that BSG1 was expressed mainly in the young panicle and elongating stem. The BSG1 mutation affected the expression of genes potentially involved in the cell cycle and GW2, an important regulator of grain size in rice. Our results suggest that BSG1 determines grain shape and size probably by modifying cell division and expansion in the grain hull. 展开更多
关键词 cell division and expansion DUF640 protein gene expression grain size lemma and palea
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水稻颖花外稃表面双峰乳突扫描电镜观察 被引量:20
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作者 张文绪 《北京农业大学学报》 CSCD 北大核心 1995年第2期143-146,共4页
用扫描电镜对普通野稻和普通栽培稻的籼粳两亚种外稃表面双峰乳突的结构作了比较观察。根据双峰距、垭深度、峰角度等特征,把双峰乳突分为两种基本类型。籼稻为"锐型",粳稻为"钝型",普通野稻为中间型。
关键词 水稻 外稃 双峰乳突
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An Upper Bound for the Adjacent Vertex-Distinguishing Total Chromatic Number of a Graph 被引量:17
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作者 LIU Xin Sheng AN Ming Qiang GAO Yang 《Journal of Mathematical Research and Exposition》 CSCD 2009年第2期343-348,共6页
Let G = (V, E) be a simple connected graph, and |V(G)| ≥ 2. Let f be a mapping from V(G) ∪ E(G) to {1,2…, k}. If arbitary uv ∈ E(G),f(u) ≠ f(v),f(u) ≠ f(uv),f(v) ≠ f(uv); arbitary uv, uw... Let G = (V, E) be a simple connected graph, and |V(G)| ≥ 2. Let f be a mapping from V(G) ∪ E(G) to {1,2…, k}. If arbitary uv ∈ E(G),f(u) ≠ f(v),f(u) ≠ f(uv),f(v) ≠ f(uv); arbitary uv, uw ∈ E(G)(v ≠ w), f(uv) ≠ f(uw);arbitary uv ∈ E(G) and u ≠ v, C(u) ≠ C(v), whereC(u)={f(u)}∪{f(uv)|uv∈E(G)}.Then f is called a k-adjacent-vertex-distinguishing-proper-total coloring of the graph G(k-AVDTC of G for short). The number min{k|k-AVDTC of G} is called the adjacent vertex-distinguishing total chromatic number and denoted by χat(G). In this paper we prove that if △(G) is at least a particular constant and δ ≥32√△ln△, then χat(G) ≤ △(G) + 10^26 + 2√△ln△. 展开更多
关键词 total coloring adjacent vertex distinguishing total coloring adjacent vertex distinguishing total chromatic number Lovasz local lemma.
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An Upper Bound for the Adjacent Vertex Distinguishing Acyclic Edge Chromatic Number of a Graph 被引量:15
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作者 Xin-sheng Liu Ming-qiang An Yang Gao 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2009年第1期137-140,共4页
A proper k-edge coloring of a graph G is called adjacent vertex distinguishing acyclic edge coloring if there is no 2-colored cycle in G and the color set of edges incident to u is not equal to the color set of edges ... A proper k-edge coloring of a graph G is called adjacent vertex distinguishing acyclic edge coloring if there is no 2-colored cycle in G and the color set of edges incident to u is not equal to the color set of edges incident to v, where uv ∈E(G). The adjacent vertex distinguishing acyclic edge chromatic number of G, denoted by χ'αα(G), is the minimal number of colors in an adjacent vertex distinguishing acyclic edge coloring of G. In this paper we prove that if G(V, E) is a graph with no isolated edges, then χ'αα(G)≤32△. 展开更多
关键词 Adjacent strong edge coloring adjacent vertex distinguishing acyclic edge coloring adjacent vertexdistinguishing acyclic edge chromatic number the LovNsz local lemma
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The Existence and Uniqueness of the Solution for Neutral Stochastic Functional Differential Equations with Infinite Delay 被引量:15
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作者 WANG Lin HU Shi Geng 《Journal of Mathematical Research and Exposition》 CSCD 2009年第5期857-863,共7页
The main aim of this paper is to establish the existence-and-uniqueness theorem for neutral stochastic functional differential equations with infinite delay at phase space BC((-∞, 0]; R^n) An example is given for ... The main aim of this paper is to establish the existence-and-uniqueness theorem for neutral stochastic functional differential equations with infinite delay at phase space BC((-∞, 0]; R^n) An example is given for illustration. 展开更多
关键词 neutral stochastic functional differential equations infinite delay existence UNIQUENESS Burkholder-Davis-Gundy inequality Borel-Cantelli lemma.
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ON THE DISTRIBUTION OF VALUES OF RANDOM DIRICHLET SERIES(II) 被引量:15
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作者 孙道椿 余家荣 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 1990年第1期33-44,共12页
For certain Dirichlet series almost surely(a.s.)of order(R) ρ∈(0,∞)in the right-halfplane,a.s.every point of the imaginary axis is a Borel point of order ρ+1 and with no finiteexoeptional value.
关键词 BOREL imaginary DIRICHLET 明七 PROOF 丁通 lemma ALGEBRA 七户 叨任
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汉语名词短语产生中的量词一致性效应 被引量:12
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作者 王黎 郭佳 +1 位作者 毕彦超 舒华 《心理与行为研究》 2006年第1期34-38,共5页
目前,语言产生领域的多数研究都集中在口语词语产生方面,许多研究者针对不同的语言系统的特色,对功能词进行了大量跨语言的研究。汉语量词是汉藏语系独有的功能词,本研究采用词图干扰范式,以名词短语和简单名词两种不同的图片命名任务,... 目前,语言产生领域的多数研究都集中在口语词语产生方面,许多研究者针对不同的语言系统的特色,对功能词进行了大量跨语言的研究。汉语量词是汉藏语系独有的功能词,本研究采用词图干扰范式,以名词短语和简单名词两种不同的图片命名任务,探讨了汉语量词的产生过程。实验结果发现,在名词短语命名任务下,存在量词的一致性效应;在名词命名的任务下,则不存在这种一致性效应。研究还发现语义干扰效应在两种不同命名任务下出现了分离。语义干扰效应只在命名名词的任务下出现,在命名名词短语的任务下未被发现。 展开更多
关键词 语言产生 词汇通达 图片命名 lemma 量词一致性效应
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稻属20个种外稃乳突的扫描电镜观察 被引量:10
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作者 张文绪 汤圣祥 《作物学报》 CAS CSCD 北大核心 1997年第3期296-300,共5页
用扫描电镜对稻属植物20个种的外稃表面乳突性状作了观察。根据乳突的形态特征,将乳突分为s类,即双峰乳突,多峰乳突,瘤峰乳突,单峰乳突和凹痕乳突。根据峰角度和垭角度性状,将双峰乳突进一步分为锐型和钝型两种类型。并研讨了乳突特征... 用扫描电镜对稻属植物20个种的外稃表面乳突性状作了观察。根据乳突的形态特征,将乳突分为s类,即双峰乳突,多峰乳突,瘤峰乳突,单峰乳突和凹痕乳突。根据峰角度和垭角度性状,将双峰乳突进一步分为锐型和钝型两种类型。并研讨了乳突特征与稻种分类的关系问题。 展开更多
关键词 稻属 外稃乳突 乳突 扫描电镜
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THE MORSE INDEX OF A SADDLE POINT 被引量:7
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作者 刘嘉荃 《Systems Science and Mathematical Sciences》 SCIE EI CSCD 1989年第1期32-39,共8页
This paper is devoted to clarifying the relationship between the classical Morse theory andthe Mountain Pass Lemma via the local linking concept.It is shown that for a C^1-function f with alocal linking,the m-thcritic... This paper is devoted to clarifying the relationship between the classical Morse theory andthe Mountain Pass Lemma via the local linking concept.It is shown that for a C^1-function f with alocal linking,the m-thcritical group is nontrivial,where m is the Morse index.Combined with thebehavior of f at infinity,this result can be used to offer the existence of nontrivial critical points. 展开更多
关键词 SADDLE point MORSE theory MOUNTAIN PASS lemma local LINKING
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The Growth Theorem for Convex Maps on the Banach Space 被引量:7
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作者 张文俊 董道珍 汪远征 《Chinese Quarterly Journal of Mathematics》 CSCD 1992年第2期84-87,共4页
In this paper,the growth theorem for convex maps on the Banach space is given, this is: ‖f(x)‖≤‖x‖/(1-‖x‖),x∈B the estimate is best possible for Hilbert space.
关键词 holomorphic maps convex maps Schwartz lemma Growth theorem
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New versions of Barbalat's lemma with applications 被引量:6
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作者 Mingzhe HOU Guangren DUAN Mengshu GUO 《控制理论与应用(英文版)》 EI 2010年第4期545-547,共3页
This note presents a set of new versions of Barbalat's lemma combining with positive (negative) definite functions.Based on these results,a set of new formulations of Lyapunov-like lemma are established.A simple ex... This note presents a set of new versions of Barbalat's lemma combining with positive (negative) definite functions.Based on these results,a set of new formulations of Lyapunov-like lemma are established.A simple example shows the usefulness of our results. 展开更多
关键词 Barbalat's lemma Lyapunov-like lemma
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The high order Schwarz-Pick lemma on complex Hilbert balls 被引量:7
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作者 DAI ShaoYu1,2,CHEN HuaiHui1 & PAN YiFei3,4 1Department of Mathematics,Nanjing Normal University,Nanjing 210097,China 2Department of General Study Program,Jinling Institute of Technology,Nanjing 211169,China +1 位作者 3School of Mathematics and Informatics,Jiangxi Normal University,Nanchang 330022,China 4Department of Mathematical Sciences,Indiana University-Purdue University Fort Wayne,Fort Wayne,IN 46805-1499,USA 《Science China Mathematics》 SCIE 2010年第10期2649-2656,共8页
In this paper we prove a high order Schwarz-Pick lemma for holomorphic mappings between unit balls in complex Hilbert spaces.In addition,a Schwarz-Pick estimate for high order Fréchet derivatives of a holomorphic... In this paper we prove a high order Schwarz-Pick lemma for holomorphic mappings between unit balls in complex Hilbert spaces.In addition,a Schwarz-Pick estimate for high order Fréchet derivatives of a holomorphic function f of a Hilbert ball into the right half-plane is obtained. 展开更多
关键词 COMPLEX HILBERT BALL high order Schwarz-Pick lemma
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Static Output Feedback Control for Discrete-time Piecewise Linear Systems: an LMI Approach 被引量:7
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作者 DING Da-Wei YANG Guang-Hong 《自动化学报》 EI CSCD 北大核心 2009年第4期337-344,共8页
关键词 Piecewise linear systems piecewise quadratic Lyapunov function Finsler's lemma static output feedback (SOF) linear matrix inequality (LMI)
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MT-1象草及其近缘品种的外稃微形态特征 被引量:9
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作者 张向前 周峰 解新明 《草业学报》 CSCD 北大核心 2010年第4期159-165,共7页
采用电镜扫描技术对MT-1象草及其近缘品种的外稃进行了观察分析。结果表明,象草外稃的微形态具有丰富的多态性,5个象草品种(品系)间,其外稃共有7种表皮细胞形态,其中以十字形、哑铃形、念珠形硅细胞最为普遍;外稃毛被主要集中在中部,各... 采用电镜扫描技术对MT-1象草及其近缘品种的外稃进行了观察分析。结果表明,象草外稃的微形态具有丰富的多态性,5个象草品种(品系)间,其外稃共有7种表皮细胞形态,其中以十字形、哑铃形、念珠形硅细胞最为普遍;外稃毛被主要集中在中部,各品种类型各异,11种毛被类型中短基微毛和有尖刺毛为共有类型。依据乳突类型,可以将5个品种(品系)分为4类。根据外稃表皮微形态的差异,可以对MT-1象草及其近缘品种进行比较鉴定并加以区分。 展开更多
关键词 象草 外稃 微形态特征 扫描电镜
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The Schwarz-Pick lemma for planar harmonic mappings 被引量:9
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作者 CHEN HuaiHui 《Science China Mathematics》 SCIE 2011年第6期1101-1118,共18页
The classical Schwarz-Pick lemma for holomorphic mappings is generalized to planar harmonic mappings of the unit disk D completely. (I) For any 0 < r < 1 and 0 ρ < 1, the author constructs a closed convex do... The classical Schwarz-Pick lemma for holomorphic mappings is generalized to planar harmonic mappings of the unit disk D completely. (I) For any 0 < r < 1 and 0 ρ < 1, the author constructs a closed convex domain Er,ρ such that F((z,r)) eiαEr,ρ = {eiαz : z ∈ Er,ρ} holds for every z ∈ D, w = ρeiα and harmonic mapping F with F(D)D and F(z) = w, where △(z,r) is the pseudo-disk of center z and pseudo-radius r; conversely, for every z ∈ D, w = ρeiα and w ∈ eiαEr,ρ, there exists a harmonic mapping F such that F(D) D, F(z) = w and F(z ) = w for some z ∈ △(z,r). (II) The author establishes a Finsler metric Hz(u) on the unit disk D such that HF(z)(eiθFz(z) + e-iθFz(z)) ≤1 /(1- |z|2)holds for any z ∈ D, 0 θ 2π and harmonic mapping F with F(D)D; furthermore, this result is precise and the equality may be attained for any values of z, θ, F(z) and arg(eiθFz(z) + e-iθFz(z)). 展开更多
关键词 harmonic mappings Schwarz-Pick lemma Finsler metric
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论明清俗语辞书的收词特点——兼论辞书编纂中的“语词分立”观与“语词兼收”观 被引量:9
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作者 曾昭聪 《暨南学报(哲学社会科学版)》 CSSCI 北大核心 2012年第6期139-146,164,共8页
词目是辞书中被解释的对象,明清俗语辞书收录词目的特点一是"字"、"词"、"语"兼收,二是"词""语"为主,"词"占重头。从明清俗语辞书"语""词"兼收的实... 词目是辞书中被解释的对象,明清俗语辞书收录词目的特点一是"字"、"词"、"语"兼收,二是"词""语"为主,"词"占重头。从明清俗语辞书"语""词"兼收的实际情况出发可以认为辞书编纂中"语""词"兼收与"语词分立"是可以并存的,明清俗语辞书的"语""词"兼收现象不能简单地判为不足。 展开更多
关键词 明清俗语辞书 词目 特点 语词分立 语词兼收
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Identities on q-Harmonic Numbers
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作者 Mengxiao Zhou Haitao Jin Huanhuan Zheng 《Journal of Applied Mathematics and Physics》 2024年第5期1796-1803,共8页
With the help of the classical Abel’s lemma on summation by parts and algorithm of q-hypergeometric summations, we deal with the summation, which can be written as multiplication of a q-hypergeometric term and q-harm... With the help of the classical Abel’s lemma on summation by parts and algorithm of q-hypergeometric summations, we deal with the summation, which can be written as multiplication of a q-hypergeometric term and q-harmonic numbers. This enables us to construct and prove identities on q-harmonic numbers. Several examples are also given. 展开更多
关键词 Harmonic Numbers q-Zeilberger Algorithm Abel’s lemma
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