屏蔽示教装置

在讲四极管、五极管等課題时,需要了解电場屏蔽原理。电場屏蔽原理比較抽象难懂,是教学中的难点,現使用屏蔽示教装置配合讲課,学員反映具体生动,印象深刻,教学效果有較明显的提高。     

SOLUTIONS FOR A NONHOMOGENEOUS ELLIPTIC PROBLEM INVOLVING CRITICAL SOBOLEV-HARDY EXPONENT IN R^N

For the following elliptic problem where 2-(s)=2(N-s)/N-2 is the critical Sobolev-Hardy exponent, h(x)∈(D1,2(RN))*, the dual space of (D1,2(RN)), with h(x)≥((?))0. By Ekeland's variational principle, subsuper solutions and a Mountain Pass theorem, the authors prove that the above problem has at least two distinct solutions if     

Exploratory study of possible resonances in heavy meson-heavy baryon coupled-channel interactions

We use a unitary coupled-channel model to study the DA_c-D∑_c interactions. In our calculation, SU(3)flavor symmetry is applied to determine the coupling constants. Several resonant and bound states with different spin and parity are dynamically generated in the mass range of the recently observed pentaquarks. The approach is also extended to the hidden beauty sector to study the BΛ_b-B∑_b interactions. As the b-quark mass is heavier than the c-quark mass, there are more resonances observed for the BΛ_b-B∑_b interactions and they are more tightly bound.     

Sb量子点掺杂钠硼硅玻璃的三阶光学非线性

采用溶胶-凝胶法以正硅酸乙酯、硼酸、金属钠为前驱体合成了含Sb量子点的钠硼硅玻璃。紫外-可见(UV-vis)吸收光谱分析表明量子点玻璃的表面等离子体共振吸收峰在566nm附近;利用飞秒激光钛宝石Z-扫描(Z-scan)技术在800nm波长处对玻璃样品的非线性光学性质进行研究,得到了该玻璃的非线性折射率γ,非线性吸收系数β和三阶非线性极化率χ(3)分别为8.59×10-17 m2/W、1.80×10-10 m/W、4.75×10-11 esu;X-射线粉末衍射(XRD)分析表明具有斜方六面体晶相结构的Sb量子点成功的掺入到玻璃基体中;通过透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)对量子点的尺寸大小和颗粒分布进行了表征,结果显示Sb量子点在玻璃中呈规则的球形,并且颗粒尺寸在19~25nm之间。     

通性通法 突破创新——海南省2011年中考数学第24题评析

数学学习能力不仅反映学生对既学知识掌握的情况和程度,更体现学生的数学学习潜能、兴趣和创新精神.数学问题层次一般包含了解、理解、掌握、灵活运用等.重考查数学的基础知识、基本技能、基本的数学思想方法,并注重通性通法,加强对数学应用意识和用数学观点分析解决问题能力的考查,体现数学探究能力的考查.     

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在强度静力分析基础上,对S弯盒壁厚、加强筋间距等参数进行了优化设计和校核。在模态分析基础上,对模型进行了频谱分析和动态时程分析,获得地震动下确保结构安全运行的设计参数。