葛庭燧院士荣获罗伯特·富兰克林·梅尔奖

中国科学院固体物理研究所（合肥）名誉所长、研究员葛庭燧院士接到美国矿物、金属和材料协会（ＴＭＳ）执行主席亚历山大·斯科特教授的通知，他被授予ＴＭＳ的ＲＦ梅尔奖，并邀请他在ＴＭＳ第１２８次年会上（１９９９年２月２８日至３月４日在圣地亚哥召开）作题为...     

第6届液体和软物质物理学术会议简讯

由中国物理学会主办、中国科学院固体物理研究所承办的第6届全国液体和软物质物理学术会议于2008年11月5日至7日在合肥市召开．中国科学院物理研究所陆坤权研究员、固体物理研究所朱震刚研究员担任本次会议主席．中国科学院固体物理研究所所长蔡伟平研究员致开幕词和欢迎词．本次会议到会98人,来自10个研究机构,还有来自日本的两位代表．     

Pb-Sn合金固—液转变过程的内耗行为

在连续升温过程中,测量了Pb-Sn合金的内耗.实验发现：在共晶成分范围内,伴随着Pb-Sn 合金的固—液转变,内耗值出现突然下降.内耗值的下降幅度与Pb-Sn合金成分有关.固—液 转变过程中的内耗是由材料结构变化或弛豫时间变化引起的. 关键词： 内耗 固—液转变 Pb-Sn合金     

缅怀何怡贞先生

2008年7月31日,中国物理界前辈,我们尊敬的何怡贞先生永远离开了我们,享年98岁.何怡贞先生给我的印象是一个非常平和谦逊的人,待人诚恳热情,平易近人,科研工作上孜孜不倦,一丝不苟.     

Apparent Electrical Conductivity of Porous Titanium Prepared by the Powder Metallurgy Method

Porous titanium is produced by thepowder metallurgy method. Dependence of the electrical conductivity on the porosity and pore size is investigated and the experimental results are compared with a number of models. It is found that the minimum solid area model could be successfully applied to describe the relationship between the electrical conductivity and the porosity of porous titanium. This kind of conductivity increases with increasing pore sizes.     

自动倒扭摆内耗仪的研制简讯

这台自动倒扭摆内耗仪的主要用途是,用衰减法测量内耗和弹性模量（与频率的平方成正比）及其与温度的关系．自１９４７年葛庭隧教授创制第一台低频扭摆内耗仪以来,内耗研究得到了迅速的发展．但是长期以来,扭摆内耗仪一直停留在只是利用灯尺进行目测的水平．随着电子技术的发展,人们注意到扭摆测量的自动化问题,即能够自动控制,自动测量和自动记录内耗、振动频率、动态弹性模量和温度．目前国际上的最先进自动倒扭摆,是?...     

液态金属结构研究新进展

文章介绍了用内耗方法研究金属液态结构的新进展，发现了随温度变化金属液态结构发生不连续的变化，并经差热分析、X射线衍射等实验证实了这种变化．这对认知金属液态结构提供了新的实验依据。     

Fundamental band gap and alignment of two-dimensional semiconductors explored by machine learning

Two-dimensional(2D)semiconductors isoelectronic to phosphorene have been drawing much attention recently due to their promising applications for next-generation(opt)electronics.This family of 2D materials contains more than 400members,including(a)elemental group-V materials,(b)binary III–VII and IV–VI compounds,(c)ternary III–VI–VII and IV–V–VII compounds,making materials design with targeted functionality unprecedentedly rich and extremely challenging.To shed light on rational functionality design with this family of materials,we systemically explore their fundamental band gaps and alignments using hybrid density functional theory(DFT)in combination with machine learning.First,calculations are performed using both the Perdew–Burke–Ernzerhof exchange–correlation functional within the generalgradient-density approximation(GGA-PBE)and Heyd–Scuseria–Ernzerhof hybrid functional(HSE)as a reference.We find this family of materials share similar crystalline structures,but possess largely distributed band-gap values ranging approximately from 0 eV to 8 eV.Then,we apply machine learning methods,including linear regression(LR),random forest regression(RFR),and support vector machine regression(SVR),to build models for the prediction of electronic properties.Among these models,SVR is found to have the best performance,yielding the root mean square error(RMSE)less than 0.15 eV for the predicted band gaps,valence-band maximums(VBMs),and conduction-band minimums(CBMs)when both PBE results and elemental information are used as features.Thus,we demonstrate that the machine learning models are universally suitable for screening 2D isoelectronic systems with targeted functionality,and especially valuable for the design of alloys and heterogeneous systems.     

全光纤傅里叶变换光谱仪的关键技术研究

研究一种基于光纤Mach-Zehnder干涉仪结构的全光纤傅里叶变换光谱仪(fiber fourier transform spectrometer, FFTS)。设计了光程调制范围可达2 cm的压电陶瓷光纤相位调制器,代替传统傅里叶变换光谱仪中的动镜产生光程扫描。实验中采用1 310 nm DFB激光器作为参考光源,对测试光干涉图进行等光程间隔采样,以消除压电陶瓷非线性光程调制产生的误差。通过对测试光干涉图做傅里叶逆变换得到测试光光谱图。利用该FFTS系统测量了ASE宽带光源的光谱,并将测量结果和光栅光谱仪测量结果进行了对比,结果表明两者所测ASE光谱线型一致。最后,利用光纤光栅作为样品,对FFTS系统的光谱分辨率进行了检测,光谱分辨率达到了0.78 cm-1。