“古池推圆”问题趣谈

今有方中古圆塘, 风吹雨打历沧桑. 三面皆被土湮没, 只露一角映残阳. 外方隅至弧中央, 七尺六寸已测量. 圆径几何如相问, 请读九韶及九章. 这首诗是笔者根据秦九韶《数书九章》     

数学谜语

!-令-峥.令-咯，令-峥-令-令-令-令-。-令-令，。-今.今-令-今少 1.错把13十1一14写成1十1一1 (打一四字成语) 2.满足。相似文献   

A Method for Determining the Phase Transition Point of the Bose-Einstein Condensation by Judging the Fitting Errors

In this paper, We demonstrate an approach to determine the phase transition point and critical temperature of Bose-Einstein condensation. During the fitting sequence of time-of-flight images, for just one picture we take four kinds of different calculations instead of only one. By calculating the quantitative least-square errors, which have always been neglected before, we find out that this value can act as a criterion to judge the status of atom clouds. Using this criterion, we can not only discriminate the status around the phase transition point, but can also find the critical point precisely. Also with this method, we can achieve the totally automatical running of calculating programs without human＇s judgments.     

YGG:Cr晶体的光谱特性

本文利用10K下的吸收谱,拟合计算了YGG:Cr的晶场能级,估算了黄昆因子和平均声子能量,讨论了R线随温度的红移和宽化.     

麻黄素季铵盐萃取金的研究

有关用季铵盐萃取金的研究已有广泛的报导。季铵盐可实现从王水、卤化物和氰化物等工艺液中提取金,并有高容量和易反萃等优点,故一直引人注目。本文研究一种新型萃取剂麻黄素季铵盐——N-十六烷基-N,N-二甲基麻黄素溴化铵(Ⅰ)用于金的萃取和精炼,该季铵盐由天然麻黄素(一)—ph(OH)CH(CH_3)NHCH_3·HCl(A)合成而得。麻黄素来源于麻黄,中医上以之入药,多产于我国北部,来源十分丰裕。烷基链长为之较短的N-十二烷基-N,N-二甲基麻黄素溴化铵(Ⅱ)作为表面活性剂用于胶束模拟酶的研究,但有关(Ⅰ)的合成及用于金的萃取方面,文献上迄今未见报导。     

用能带理论研究过渡金属fcc{110}表面的重构

用LEED研究了过渡金属fcc{110}表面的重构。发现当理论与实验之间符合得最好的结构是:顶层原子为失排模型,第二层原子为对排模型,第三层原子为锯齿模型和第四层原子是折模型。对这些重构表面的弛豫率(α)是:-0.034(对Cu),-0.069(对Pd),-0.079(对Ag),-0.117(对Au),-0.074(对Ni),-0.144(对Pt)和-0.147(对Ir)。