共查询到20条相似文献，搜索用时 62 毫秒
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首先给出坐标本征态的Fock表象,然后推导出真空投影算符0〉〈0的正规乘积形式,最后利用IWOP技术导出了单模压缩算符S=∫∞-∞（dx/u（1/2）~2│x/μ〈x│=e-（a＋2/2）thλe（a＋a＋1/2）Insechλe（a2/2）thλ,并分析了其压缩特性。 相似文献
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研究了带有临界势型阻尼系数（1＋│x│）-1和非线性项│u│p-1u非线性波动方程的Cauchy问题.当初始函数具有紧支集时,利用乘子法建立恒等式ddtE（t）＋F（t）=0并巧妙地选取f（t）,g（t）,h（t）得出整体解的总能量衰减估计.利用类似方法研究带有临界势型阻尼系数（1＋│x│＋t）-1和非线性项│u│p-1u非线性波动方程的Cauchy问题,当初始函数具有紧支集时,得到相似的结果. 相似文献
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利用Sobolev-Hardy不等式、集中紧原理、山路几何给出关于Sobolev-Hardy指数的含奇性p-拉普拉斯方程：-div〔（｜▽u｜p-2▽u）/｜x｜β〕=（up＊-1）/｜x｜α＋λuq-1,inΩ;u=0,onΩ 相似文献
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研究Dirichlet问题-=λ（u~p＋u~q）,u（0）=u（1）=0,其中1〈p〈q〈＋∞,参数λ〉0,得到了在1〈p〈q〈p＋1条件下,存在λ＊〉0,当λ≤λ＊时,此方程无正解;当λ〉λ＊时,此方程恰好有一个正解. 相似文献
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考虑如下边值问题-u″=λ^2u＋αf（u）＋g（｜u＇｜） （1）u（0）=u（1）=0 （2）正解的存在性,其中λ＞0,α≥0为参数;f∈C（R,R＋）,g∈C（R＋,R＋）,满足g（s）＞0,s＞0;lims→0f（s）/s=0,lims→0g（s）/s=0,∫∞sds/α＋g（s）=∞,α＞0,∫ds/g（s）＜∞.在上述条件下,我们证明了,对任一0＜λ＜π,α≥0,边值问题（1）-（2）至少存在一个正解,对λ≥ττ边值问题（1）-（2）没有正解. 相似文献
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研究了如下的非线性椭圆方程正爆破解存在性：{△u＋g（x）u^a│△↓u│q=ρ（x）f（u）,x∈Ω;其中Ω R^N（N≥3）。其中QCR“（N≥3）是一个C^2类有界区域或者Ω=R^N,a≤0,q∈[0,2]。运用上下解定理和摄动方法,得到了若干正爆破解存在的充分性条件,并就解存在的必要性做了论证。 相似文献
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姚庆六 《周口师范学院学报》2011,28(5)
考察了非线性三阶三点特征值问题
{u^m（t）＋λf（t,u（t）,u′（t）,u″（t））=0,0〈t〈1,
u（0）=a,u′（η）=βu″（1）=γ,
其中非线性项f（t,u0,u1,u2）是一个强Caratheodory函数．证明了当a^2＋β^2＋γ^2〉0或者∫1 0｜f（t,0,0,0）｜dt〉0时存在λ^＊〉0使得对于任何0〈λ≤λ^＊,此问题至少有一个非平凡解。 相似文献
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饶若峰 《黄冈师范学院学报》2003,23(3):3-6
给出了半线性椭圆方程-△u=λ1u |u|^2^*-2u τ(x,u)的Dirichlet问题在对扰动项τ（x,u）增加适当条件后非平凡解的存在性定理，以及方程-△u=λu-|u 2^*-2u h(x),λ∈[λ1,λk]（这里λk是方程-△u=λu的第κ个互不相等的特征值）的非零解的存在性定理。 相似文献
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讨论了拟线性椭圆方程-u″＋u-k（u^2）″u=f（x,u）,x∈R（＊）,其中k〉0是常数,f（x,u）是一个关于“的超线性和次临界函数,且f（x,0）=0．在函数f（x,u）满足某些条件下,通过变分法证明了方程（＊）至少存在一个正解． 相似文献
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人教版高中数学（必修2）P120第4题如下：
已知直线l1：A1x＋B1y＋C1=0与l2：A2x＋B2y＋C2=0相交,证明议程：A1x＋B1y＋C1＋λ（A2x＋B2y＋C2）=0（λ∈R）（＊）,表示过l1与l2交点的直线. 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献