期刊文献+
共找到1,571篇文章
< 1 2 79 >
每页显示 20 50 100
Plant Hardiness Zones of China 被引量:1
1
作者 Chen YouminDepartment of Landscape Architecture. Beijing Forestry University 《北京林业大学学报》 CAS CSCD 北大核心 1992年第S2期90-92,共3页
China has been divided into eleven plant hardiness zones based on average annunal minimum temperatures.
关键词 hardiness ZONE minimum TEMPERATURE ISOHYET
下载PDF
Short-day treatment during the growing period limits shoot growth and increases frost hardiness of hybrid aspen plants in the nursery
2
作者 Zhang Gang Jaana Luoranen Heikki Smolander 《Forestry Studies in China》 CAS 2007年第4期262-266,共5页
In Finland, under nursery conditions hybrid aspen may continue their shoot growth until early September. Thus, frost hardening is usually delayed. To solve this problem, we used a three-week period of short-day (SD)... In Finland, under nursery conditions hybrid aspen may continue their shoot growth until early September. Thus, frost hardening is usually delayed. To solve this problem, we used a three-week period of short-day (SD) treatment between late July and mid-August. During autumn after frost exposure, frost hardiness (FH) was assessed three times with a stem-browning test. The resuits showed that after SD treatment shoot growth ceased and FH increased when compared to untreated hybrid aspen. Furthermore, the height of SD-treated hybrid aspen varied much less than that of the control plants. We conclude that SD treatment in the nursery during the growing period can be used as a supplementary method for producing well-hardened and uniform hybrid aspen plants. 展开更多
关键词 frost hardiness nursery performance POPULUS shoot elongation short-day treatment
下载PDF
基于傅里叶变换的不确定性原理
3
作者 于海燕 郑神州 《大学物理》 2024年第1期1-4,共4页
以波函数的规范化模平方积分作为概率密度函数,我们给出了在L 2意义下的位移函数与速度函数的方差乘积有正下界的海森伯不等式;并用傅里叶变换的微分性质、Plancherel等式以及Cauchy-Schwarz不等式作了证明.另外,Hardy不确定性原理表明... 以波函数的规范化模平方积分作为概率密度函数,我们给出了在L 2意义下的位移函数与速度函数的方差乘积有正下界的海森伯不等式;并用傅里叶变换的微分性质、Plancherel等式以及Cauchy-Schwarz不等式作了证明.另外,Hardy不确定性原理表明可积函数和它的傅里叶变换不能同时迅速衰减,其最优的衰减方式是取高斯函数形式达到等式;基于Phragmen-Lindelof定理(无界区域上的最大模原理),给出了Hardy不确定性的复分析方法证明;最后我们给出了推广的Morgan不等式和Beurling不确定性. 展开更多
关键词 傅里叶变换 海森伯不确定性 Hardy不确定性 Morgan不等式 Beurling不确定性
下载PDF
Assessing frost hardiness of Pinus bungeana shoots and needles by electrical impedance spectroscopy with and without freezing tests 被引量:12
4
作者 Gang Zhang Ya-qing Li Sheng-hao 《Journal of Plant Ecology》 SCIE 2010年第4期285-293,共9页
Aims Nursery and forest operations require that frost hardiness results be produced faster than can be provided by controlled freezing tests.There is a great challenge to develop a rapid method for predicting frost ha... Aims Nursery and forest operations require that frost hardiness results be produced faster than can be provided by controlled freezing tests.There is a great challenge to develop a rapid method for predicting frost hardiness that might not necessitate controlled freezing tests.The aim of this study was to examine the assessment of the frost hardiness of shoots and needles of Pinus bungeana by electrical impedance spectroscopy(EIS)with and without controlled exposure to freezing.Methods The frost hardiness of current-year shoots and needles of P.bungeana in an 8-year-old provenance field trial was measured at Shisanlin Nursery in Beijing,China,from September 2006 to January 2007 by means of EIS and conventional electrolyte leakage(EL).In the same plants,but without controlled freezing test,were monitored the EIS parameters in current-year shoots and needles.Important Findings The results showed that(i)after controlled freezing tests,the frost hardiness estimated by EIS parameters(extracellular resistance,re,and membrane time constant,sm)was significantly correlated with the frost hardiness assessed by EL method(r=0.95)and(ii)for the samples not exposed to controlled freezing treatment,the relaxation time s1 for shoots and b for needles had greater correlations with the frost hardiness estimated by EL after controlled freezing tests relative to the other parameters(r=0.90 for shoots and r=0.84 for needles,respectively).The parameters re of shoots and needles and sm of needles might be applied for measuring frost hardiness of samples after exposed to controlled freezing tests.The frost hardiness results can be obtained within 48 h.The parameters s1 of shoots and b of needles could be used for estimating the frost hardiness of samples without using a controlled freezing test.The frost hardiness results can be obtained within 24 h. 展开更多
关键词 cold hardiness electrical impedance spectroscopy electrolyte leakage Pinus bungeana
原文传递
Seasonal and geographical variation in diapause and cold hardiness of the Asian corn borer, Ostrinia furnacalis 被引量:3
5
作者 Hai-Cui Xie Dun-Song Li +5 位作者 Hong-Gang Zhang Charles E. Mason Zhen-Ying Wang Xin Lu Wan-Zhi Cai Kang-Lai He 《Insect Science》 SCIE CAS CSCD 2015年第4期578-586,共9页
Asian corn borer, Ostrinia furnacalis (Guenee), is a key corn pest in the Asian-Western Pacific countries. It overwinters as flail-grown larvae in plant stalks or in a spun-silk covering located in the plant debris ... Asian corn borer, Ostrinia furnacalis (Guenee), is a key corn pest in the Asian-Western Pacific countries. It overwinters as flail-grown larvae in plant stalks or in a spun-silk covering located in the plant debris in the temperate regions of China. Supercooling point (SCP) and survival rate after low sub-zero temperature treatment were assessed for field-collected populations in the laboratory using a cool bath with a 1 ℃/min cooling rate until -40℃. Mean SCPs were varied among geographical populations, with a significant decline from -22.7℃ of Haikou, the multivoltine tropical population in the south, to -28.5℃ of Gongzhuling, the univoltine temperate population in the northeast of China. In addition, there was more than 1℃ difference in SCP between Gongzhuling univoltine and bivoltine populations that were from the same geographic origin. Mean SCPs of the Guangzhou population fluctuated over the year, with significantly lower SCPs in winter than in other seasons, which correlated with a significantly higher proportion of diapausing larvae in winter than in other seasons. Over 41% of overwintering larvae from the northeast population could withstand to be supercooled for a few minutes to the low sub-zero temperature of-40℃, but only 6.7% of their southern counterparts did so. The findings from this study suggest that O. furnacalis mostly takes advantage of freeze avoidance as diapausing larvae for overwintering in the southern region, whereas it exhibits freeze tolerance in diapause in the northeastern region. 展开更多
关键词 cold hardiness DIAPAUSE geographical population Ostriniafurnacalis OVERWINTERING SEASONALITY
原文传递
一类带Hardy项和Sobolev临界指数的椭圆型方程正解的存在性
6
作者 李卫 王炜 +2 位作者 李泽俊 赵秀娟 万优艳 《理论数学》 2024年第10期14-18,共5页
本文研究了一类带Hardy项和Sobolev临界指数的椭圆型方程。通过变分法,我们得到了方程的能量泛函在零点附近存在局部极小值点,且该极小值点为方程的正解。此外,当方程的扰动项趋于零时,该正解也趋于零。The elliptical equation with Ha... 本文研究了一类带Hardy项和Sobolev临界指数的椭圆型方程。通过变分法,我们得到了方程的能量泛函在零点附近存在局部极小值点,且该极小值点为方程的正解。此外,当方程的扰动项趋于零时,该正解也趋于零。The elliptical equation with Hardy terms and Sobolev critical exponents is studied. By the variational methods, we have obtained that there exists a local minimum point of the energy functional related to the equation which is near zero, and the local minimum point is a positive solution of this equation. Moreover, this positive solution tends to zero when the perturbed term goes to zero. 展开更多
关键词 变分方法 Hardy项 SOBOLEV临界指数 正解 扰动项
下载PDF
BIG HANKEL OPERATORS ON HARDY SPACES OF STRONGLY PSEUDOCONVEX DOMAINS
7
作者 陈伯勇 江良英 《Acta Mathematica Scientia》 SCIE CSCD 2024年第3期789-809,共21页
In this article,we investigate the(big) Hankel operator H_(f) on the Hardy spaces of bounded strongly pseudoconvex domains Ω in C^(n).We observe that H_(f ) is bounded on H~p(Ω)(1 <p <∞) if f belongs to BMO a... In this article,we investigate the(big) Hankel operator H_(f) on the Hardy spaces of bounded strongly pseudoconvex domains Ω in C^(n).We observe that H_(f ) is bounded on H~p(Ω)(1 <p <∞) if f belongs to BMO and we obtain some characterizations for Hf on H^(2)(Ω) of other pseudoconvex domains.In these arguments,Amar's L^(p)-estimations and Berndtsson's L^(2)-estimations for solutions of the ■_(b)-equation play a crucial role.In addition,we solve Gleason's problem for Hardy spaces H^(p)(Ω)(1 ≤p≤∞) of bounded strongly pseudoconvex domains. 展开更多
关键词 Hankel operator Hardy space Bergman space pseudoconvex domain
下载PDF
高维Hardy算子及其交换子的双权不等式
8
作者 王瑶瑶 吕玫钏 李文明 《数学物理学报(A辑)》 CSCD 北大核心 2024年第3期539-546,共8页
设P为Rn上的Hardy算子,Q为P的对偶算子.该文得出了P,Q以及与CMO函数构成的交换子的双权不等式.
关键词 HARDY算子 交换子 CMO 双权不等式
下载PDF
Weighted multilinear p-adic Hardy operators and commutators on p-adic Herz-type spaces
9
作者 MA Teng ZHOU Jiang 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2024年第3期554-570,共17页
In this paper,we introduce the weighted multilinear p-adic Hardy operator and weighted multilinear p-adic Ces`aro operator,we also obtain the boundedness of these two operators on the product of p-adic Herz spaces and... In this paper,we introduce the weighted multilinear p-adic Hardy operator and weighted multilinear p-adic Ces`aro operator,we also obtain the boundedness of these two operators on the product of p-adic Herz spaces and p-adic Morrey-Herz spaces,the corresponding operator norms are also established in each case.Moreover,the boundedness of commutators of these two operators with symbols in central bounded mean oscillation spaces and Lipschitz spaces on p-adic Morrey-Herz spaces are also given. 展开更多
关键词 Morrey-Herz spaces weighted multilinear p-adic Hardy operator COMMUTATORS operator norms
下载PDF
THE BOUNDEDNESS OF OPERATORS ON WEIGHTED MULTI-PARAMETER LOCAL HARDY SPACES
10
作者 丁卫 汤彦 朱月萍 《Acta Mathematica Scientia》 SCIE CSCD 2024年第1期386-404,共19页
Though atomic decomposition is a very useful tool for studying the boundedness on Hardy spaces for some sublinear operators,untill now,the boundedness of operators on weighted Hardy spaces in a multi-parameter setting... Though atomic decomposition is a very useful tool for studying the boundedness on Hardy spaces for some sublinear operators,untill now,the boundedness of operators on weighted Hardy spaces in a multi-parameter setting has been established only by almost orthogonality estimates.In this paper,we mainly establish the boundedness on weighted multi-parameter local Hardy spaces via atomic decomposition. 展开更多
关键词 weighted multi-parameter local Hardy spaces atomic decomposition BOUNDEDNESS inhomogeneous Journéclass
下载PDF
MAXIMAL FUNCTION CHARACTERIZATIONS OF HARDY SPACES ASSOCIATED WITH BOTH NON-NEGATIVE SELF-ADJOINT OPERATORS SATISFYING GAUSSIAN ESTIMATES AND BALL QUASI-BANACH FUNCTION SPACES
11
作者 林孝盛 杨大春 +1 位作者 杨四辈 袁文 《Acta Mathematica Scientia》 SCIE CSCD 2024年第2期484-514,共31页
Assume that L is a non-negative self-adjoint operator on L^(2)(ℝ^(n))with its heat kernels satisfying the so-called Gaussian upper bound estimate and that X is a ball quasi-Banach function space onℝ^(n) satisfying som... Assume that L is a non-negative self-adjoint operator on L^(2)(ℝ^(n))with its heat kernels satisfying the so-called Gaussian upper bound estimate and that X is a ball quasi-Banach function space onℝ^(n) satisfying some mild assumptions.Let HX,L(ℝ^(n))be the Hardy space associated with both X and L,which is defined by the Lusin area function related to the semigroup generated by L.In this article,the authors establish various maximal function characterizations of the Hardy space HX,L(ℝ^(n))and then apply these characterizations to obtain the solvability of the related Cauchy problem.These results have a wide range of generality and,in particular,the specific spaces X to which these results can be applied include the weighted space,the variable space,the mixed-norm space,the Orlicz space,the Orlicz-slice space,and the Morrey space.Moreover,the obtained maximal function characterizations of the mixed-norm Hardy space,the Orlicz-slice Hardy space,and the Morrey-Hardy space associated with L are completely new. 展开更多
关键词 Hardy space ball quasi-Banach function space Gaussian upper bound estimate non-negative self-adjoint operator maximal function
下载PDF
Toeplitz算子在Hardy空间上的复对称性
12
作者 富佳 李然 《石河子大学学报(自然科学版)》 CAS 北大核心 2024年第2期238-245,共8页
复对称算子是由复对称矩阵的概念抽象出来的,本文借助矩阵研究如何刻画经典Hardy空间上的一类复对称Toeplitz算子。首先在Hardy空间上定义两类新的共轭算子,它们分别为n倒置的共轭算子和n二次倒置的共轭算子。其次分奇偶情况去完整刻画... 复对称算子是由复对称矩阵的概念抽象出来的,本文借助矩阵研究如何刻画经典Hardy空间上的一类复对称Toeplitz算子。首先在Hardy空间上定义两类新的共轭算子,它们分别为n倒置的共轭算子和n二次倒置的共轭算子。其次分奇偶情况去完整刻画在这类共轭算子下Toeplitz算子是复对称的结构,利用在Hardy空间上经典正规正交基下Toeplitz算子的矩阵表示,给出了Toeplitz算子分别相对于一类共轭算子是复对称的充分必要条件。最后对本文进行总结及展望,提出能否继续刻画Toeplitz算子相对于这类共轭算子是m-复对称的问题。 展开更多
关键词 HARDY空间 TOEPLITZ算子 共轭算子 复对称算子 矩阵表示
下载PDF
一类带有Hardy项的椭圆型方程正解的存在性
13
作者 杨林 樊永红 王琳琳 《曲阜师范大学学报(自然科学版)》 CAS 2024年第3期23-28,33,共7页
研究了一类带有Hardy项的椭圆型方程在诺伊曼边界条件下正解的存在性.在反应项和边界处均呈指数增长时,利用近似方法和Brouwer不动点定理证明了该方程至少存在一个正解.
关键词 半线性椭圆型方程 Hardy项 Brouwer定理
下载PDF
Hardy空间单连通域上的Carleson测度
14
作者 王贤兴 刘梅 《理论数学》 2024年第4期45-52,共8页
Carleson测度在经典的解析函数空间之中已经有了许多漂亮的结果,那么一个很自然的问题就是:Carleson测度在一般单连通域上的解析空间中具有哪些刻画?本文继María之后,我们应用拟共形映射的相关性质将经典的Hardy空间延拓到一般单... Carleson测度在经典的解析函数空间之中已经有了许多漂亮的结果,那么一个很自然的问题就是:Carleson测度在一般单连通域上的解析空间中具有哪些刻画?本文继María之后,我们应用拟共形映射的相关性质将经典的Hardy空间延拓到一般单连通域上,并继续研究与在一般单连通域上定义的Hardy空间相关的Carleson测度的等价刻画。我们还研究了小Carleson测度的类比陈述。 展开更多
关键词 CARLESON测度 HARDY空间 小Carleson测度
下载PDF
一类 H¨ormander 型条件的奇异积分算子交换子的估计
15
作者 陈佳美 《理论数学》 2024年第1期104-113,共10页
本文讨论了一类变形的 H¨ormander 型条件的奇异积分算子与 BMO 函数生成的交换子在 Herz型 Hardy 空间的估计。
关键词 一类变 H¨ormander 型条件 BMO 函数 交换子 Herz Hardy 空间
下载PDF
一类带Hardy项的p-Laplace方程正解的先验估计
16
作者 闫慧敏 谢君辉 《延边大学学报(自然科学版)》 CAS 2024年第1期23-30,共8页
研究了一类带Hardy项椭圆型p-Laplace方-Δ_(p)u=u^(q)|x|^(a)+h(x,u,■u)解的先验估计,其中3<p<N,p-1<q<(N-α)(p-1)N-p,0<a<2.在假设h(s,u,Vu)满足一定的条件下,首先运用Doubling引理证明了解的一个衰减估计,然后运... 研究了一类带Hardy项椭圆型p-Laplace方-Δ_(p)u=u^(q)|x|^(a)+h(x,u,■u)解的先验估计,其中3<p<N,p-1<q<(N-α)(p-1)N-p,0<a<2.在假设h(s,u,Vu)满足一定的条件下,首先运用Doubling引理证明了解的一个衰减估计,然后运用blowup技巧并结合Liouville定理证明了非负解的先验估计。 展开更多
关键词 P-LAPLACE方程 Hardy项 先验估计 Doubling引理 LIOUVILLE定理
下载PDF
三圆盘Hardy空间上的Toeplitz算子与小Hankel算子的交换性
17
作者 钟意 许安见 《兰州工业学院学报》 2024年第2期91-96,共6页
Toeplitz算子的交换性问题是算子理论中的一个研究热点,在不同的函数空间下有不同的体现。在H^(2)(D^(3))空间上,对等式T^(*)_(f)H_(g)=H_(g)T_(f*)进行了研究,给出了f与g为一般函数和特殊函数时,T^(*)_(f)H_(g)=H_(g)T_(f*)成立的充要... Toeplitz算子的交换性问题是算子理论中的一个研究热点,在不同的函数空间下有不同的体现。在H^(2)(D^(3))空间上,对等式T^(*)_(f)H_(g)=H_(g)T_(f*)进行了研究,给出了f与g为一般函数和特殊函数时,T^(*)_(f)H_(g)=H_(g)T_(f*)成立的充要条件,再针对Toeplitz算子与小Hankel算子在三圆盘上的交换性问题,利用函数的多重Fourier分解,取三圆盘的一组正规正交基,通过算子作用在正规正交基上,得到Toeplitz算子与小Hankel算子可交换的充要条件。在H^(2)(D^(n))上也有类似的结论成立。 展开更多
关键词 TOEPLITZ算子 小Hankel算子 HARDY空间
下载PDF
拟共形映射的Hardy和Bergman空间
18
作者 王贤兴 唐树安 《贵州工程应用技术学院学报》 2024年第3期30-34,共5页
利用拟共形映射理论,给出了实R^(n)空间中拟共形映射的Hardy和Bergman空间的一些分析和几何刻画。
关键词 拟共形映射 HARDY空间 BERGMAN空间
下载PDF
调和Hardy空间上的Toeplitz算子的酉等价性
19
作者 丁宣浩 黄雨浩 李永宁 《数学物理学报(A辑)》 CSCD 北大核心 2023年第1期27-34,共8页
记H_(2)是单位圆盘D={ξ∈C:|ξ|<1}上的经典Hardy空间.设u和v是内函数且至少其中一个是非常值的,调和Hardy空间H_(u,v)^(2)定义为H_(u,v)^(2)=uH_(2)⊕v(H_(2))丄=uH_(2)⊕vzH_(2).对任意的x∈H_(u,v)^(2),定义H_(u,v)^(2)上的调和T... 记H_(2)是单位圆盘D={ξ∈C:|ξ|<1}上的经典Hardy空间.设u和v是内函数且至少其中一个是非常值的,调和Hardy空间H_(u,v)^(2)定义为H_(u,v)^(2)=uH_(2)⊕v(H_(2))丄=uH_(2)⊕vzH_(2).对任意的x∈H_(u,v)^(2),定义H_(u,v)^(2)上的调和Toeplitz算子Tφx=Qu,v(φx),其中,Qu,v:L_(2)→H_(u,v)^(2)为正交投影.该文刻画了调和Toeplitz算子和对偶截断Toeplitz算子的酉等价性,并给出了两个调和Toeplitz算子可交换的充要条件,调和Toeplitz代数的性质以及Tz的换位子的刻画.最后,该文还得到了有限多个连续符号的调和Toeplitz算子乘积的本质谱. 展开更多
关键词 调和Hardy空间 调和Toeplitz算子 酉等价 对偶截断Toeplitz算子 本质谱
下载PDF
Hardy空间上的Volterra-复合算子
20
作者 丁宣浩 邵长慧 李永宁 《西南师范大学学报(自然科学版)》 CAS 2023年第2期40-45,共6页
Hardy空间是一类在单位圆盘上的很重要的解析函数空间,其上的Volterra算子经过广泛的研究,已经获得了很显著的理论成果.复合算子理论也建立起了算子理论研究与函数论中经典问题研究之间的桥梁.记H^(2)为单位圆盘D上的Hardy空间.通过对H^... Hardy空间是一类在单位圆盘上的很重要的解析函数空间,其上的Volterra算子经过广泛的研究,已经获得了很显著的理论成果.复合算子理论也建立起了算子理论研究与函数论中经典问题研究之间的桥梁.记H^(2)为单位圆盘D上的Hardy空间.通过对H^(2)上的Volterra算子V以及复合算子Cφ的研究,本文引入了Hardy空间上的Volterra-复合算子Vφ,给出了Vφ的有界性、紧性、核的刻画,同时还研究了Vφ的特征值及其奇异值. 展开更多
关键词 HARDY空间 Volterra-复合算子 有界性 紧性 特征值 奇异值
下载PDF
上一页 1 2 79 下一页 到第
使用帮助 返回顶部