Ba（n，x）~（134）Cs，~（134）Ba（n，2n）~（133）Ba，

用中子活化法相对于５４Ｆｅ（ｎ，Ｐ）５４Ｍｎ反应，在１３．５０—１４．８０ＭｅＶ中子能区测量了Ｂａ（ｎ，ｘ）１３４Ｃｓ，１３４Ｂａ（ｎ，２ｎ）１３３Ｂａ，１４０Ｃｅ（ｎ，２ｎ）１３９Ｃｅ，１４２Ｃｅ（ｎ，２ｎ）１４１Ｃｅ和２３Ｎａ（ｎ，２ｎ）２２Ｎａ的反应截面．并将所测的结果和其他作者的结果进行了比较，中子能量是用９０Ｚｒ（ｎ，２ｎ）８９ｍ＋ｇＺｒ反应和９３Ｎｂ（ｎ，２ｎ）９２ｍＮｂ反应截面比法测定的。     

Ge(SiO2)n团簇结构和电子性质的密度泛函理论研究

采用密度泛函理论中的广义梯度近似(GGA)对Ge(SiO2)n (n = 1—7)团簇的几何构型进行优化,并对能量、频率和电子性质进行了计算。 结果表明,Ge(SiO2)n的最低能量结构是在(SiO2)n端位O原子以及近邻端位O原子的Si原子上吸附一个Ge原子优化得到;随着锗原子数的增加,增加的锗原子易与原来的锗原子形成锗团簇。掺杂锗原子后团簇的能隙比(SiO2)n团簇的能隙小,当多个Ge原子掺杂到(SiO2)3团簇时,其能隙随着Ge原子个数的增加出现了振荡,Gem(SiO2)3的能隙从可见光区到近红外光区变化。二阶能量差分、分裂能表明Ge(SiO2)2和Ge(SiO2)5团簇是稳定的。     

Cross-section measurements for (n, 2n) reactions on stannum isotopes in the neutron energy range of 13.5 to 14.6 MeV

Cross-sections for (n, 2n) reactions have been measured on stannum isotopes at the neutron energies of 13.5 to 14.6 MeV using the activation technique. Data are reported for the following reactions:112Sn(n, 2n)111Sn, 118Sn(n, 2n)117Sn and 124Sn(n, 2n)123mSn. The neutron fluences were determined using the monitor reaction 93Nb(n, 2n)92mNb or 27Al(n, α)24Na. The results of present work were compared with data published previously.     

Cross-Section Measurements for Reactions on Platinum Isotopes in the Neutron Energy Range of 13.5 to 14.6MeV

Cross-sections for (n,2n) and (n,p) reactions have been measured on platinum isotopes at the neutron energies of 13.5 to 14.6 MeV using the activation technique. Data were reported for the following reactions: Pt(n,2n)197m+gPt,198Pt(n,2n)197mPt,192Pt(n,2n)191Pt, 194Pt(n,p)194Ir, 195Pt(n, p)195mIr, and 196Pt(n,p)196mIr. At the neutron energies of 13.5, 14.1 and 14.6 MeV, the cross sections in mb are 2038±159, 1919±73 and 1836±68 for 198Pt(n,2n)197m+gPt reaction; 974±37, 1055±39 and 1042±39 for 198Pt(n, 2n)197mPt reaction, respectively. The cross sections are 1680±103, 1810±67 and 2047±97 for 192Pt(n,2n)191Pt reaction, and 1.0±0.2, 1.6±0.2 and 1.8±0.2 for 195Pt(n, p)195mIr reaction, respectively, at energies of 14.1, 14.4 and 14.6MeV. At 14.1 and 14.4 MeV neutron energies, the cross sections are 3.8±0.4 and 5.4±0.5 for 194Pt(n,p)194Ir reaction. While, the data are (1.13±0.07) and (1.18±0.06) mb at energies of 13.5 and 14.4 MeV, respectively, for 196Pt(n,p)196mIr reaction.The neutron fluences were determined using the monitor reaction 93Nb(n, 2n)92mNb or 27Al(n, a)24Na. A comparison was made between the present cross sections and the collected data for the measured reactions.     

(n,2n)反应同质异能态截面比

在统计理论及考虑角动量守恒的激子模型的基础上,运用Monte Carlo方法计算(n,20)反应同质异能态截面比. 以⁵⁹Co(n,2n)⁵⁸Co、⁹³Nb(n,2n)⁹²Nb和¹⁸¹Ta(n,2n)¹⁸⁰Ta的3个反应道为例,计算从其阈能到20MeV能区的同质异能态截面比,并和已有实验数据做了比较,结果符合较好. 这表明本文提供的方法是计算(n,2n)反应同质异能态截面比的一种有效方法.     

Laser ablation synthesis of new gold phosphides using red phosphorus and nanogold as precursors. Laser desorption ionisation time-of-flight mass spectrometry

Gold phosphides show unique optical or semiconductor properties and there are extensive high technology applications, e.g. in laser diodes, etc. In spite of the various AuP structures known, the search for new materials is wide. Laser ablation synthesis is a promising screening and synthetic method. Generation of gold phosphides via laser ablation of red phosphorus and nanogold mixtures was studied using laser desorption ionisation time-of-flight mass spectrometry (LDI TOFMS). Gold clusters Au(m)(+) (m?=?1 to ~35) were observed with a difference of one gold atom and their intensities were in decreasing order with respect to m. For P(n)(+) (n?=?2 to ~111) clusters, the intensities of odd-numbered phosphorus clusters are much higher than those for even-numbered phosphorus clusters. During ablation of P-nanogold mixtures, clusters Au(m)(+) (m?=?1-12), P(n)(+) (n?=?2-7, 9, 11, 13-33, 35-95 (odd numbers)), AuP(n)(+) (n?=?1, 2-88 (even numbers)), Au(2)P(n)(+) (n?=?1-7, 14-16, 21-51 (odd numbers)), Au(3)P(n)(+) (n?=?1-6, 8, 9, 14), Au(4)P(n)(+) (n?=?1-9, 14-16), Au(5)P(n)(+) (n?=?1-6, 14, 16), Au(6)P(n)(+) (n?=?1-6), Au(7)P(n)(+) (n?=?1-7), Au(8)P(n)(+) (n?=?1-6, 8), Au(9)P(n)(+) (n?=?1-10), Au(10)P(n)(+) (n?=?1-8, 15), Au(11)P(n)(+) (n?=?1-6), and Au(12)P(n)(+) (n?=?1, 2, 4) were detected in positive ion mode. In negative ion mode, Au(m)(-) (m?=?1-5), P(n)(-) (n?=?2, 3, 5-11, 13-19, 21-35, 39, 41, 47, 49, 55 (odd numbers)), AuP(n)(-) (n?=?4-6, 8-26, 30-36 (even numbers), 48), Au(2)P(n)(-) (n?=?2-5, 8, 11, 13, 15, 17), A(3) P(n)(-) (n?=?6-11, 32), Au(4)P(n)(-) (n?=?1, 2, 4, 6, 10), Au(6)P(5)(-), and Au(7)P(8)(-) clusters were observed. In both modes, phosphorus-rich Au(m)P(n) clusters prevailed. The first experimental evidence for formation of AuP(60) and gold-covered phosphorus Au(12)P(n) (n?=?1, 2, 4) clusters is given. The new gold phosphides generated might inspire synthesis of new Au-P materials with specific properties.     

Sin－1N和Sin－2N2（n=3~9）团簇结构与光振动能谱

用密度泛函理论(Density Functional Theory,DFT)的B3LYP/ 6-311G(d)方法,对Sin－1N和Sin－2N2 (n=3~9)团簇的几何构型、总能量、光振动能谱等性质进行了理论研究.通过对基态结构的几何参量分析发现,对Sin－2N2 (n=3~9)团簇,只有在SiN2和Si2N2结构中N-N成键;n＞4团簇结构,N-N不成键.对团簇能量讨论的结果表明;对于Sin－1N (n=3~9)团簇,总原子数是偶数的团簇比奇数的稳定;对于Sin－2N2(n=3~9)团簇,总原子数是奇数的团簇比偶数的稳定.     

(n,n)-(2n, 0)碳纳米管异质结的扭转力学特性

相近直径的锯齿型和扶手椅型碳纳米管可以共轴组合形成5-7碳环交替出现的柱形对称异质结. 本文利用分子动力学方法研究了直径相近且等长锯齿型和扶手椅型碳纳米管形成的(n, n)-(2n, 0)结在扭转过程中的扭矩和轴向应力随扭转角度的变化规律以及应力传递过程. 研究发现, (n, n)-(2n, 0)结扭转应变在达弹性限度内不会产生轴向应力, 该效应对基于碳纳米管扭转特性的纳米振荡器件的设计具有重要意义.     

14MeV中子引起的Pb(n,x)203Hg, W(n,x)182Ta和W(n,x)183Ta的核反应截面测量

利用活化方法测量了14MeV中子引起的Pb(n,x)²⁰³Hg,W(n,x)¹⁸²Ta和W(n,x)¹⁸³Ta的反应截面.中子注量由监督反应⁹³Nb(n,2n)^92mNb给出,中子能量利用⁹⁰Zr(n,2n)^89m+gZr和⁹³Nb(n,2n)^92mNb反应的截面比来确定.     

第一性原理对GanP-m阴离子团簇结构及其光电子能谱的研究

本文利用密度泛函理论(DFT)对GanP-(n=2-7)和GanP2-(n=1-6)阴离子团簇的几何结构、电子态及稳定性进行了研究.在B3LYP/6-31G*水平上进行了结构优化和频率分析,得到了GanP-(n=2-7)和GanP2-(n=1-6)团簇的基态结构.这些阴离子团簇的几何结构随着n的增大,在n=5时由平面结构转化为立体结构;在GanP2-(n=1-6)团簇中,P-P比Ga-P容易成键;在GanP-(n=2-7)和GanP2-(n=1-6)阴离子团簇中,Ga3P2-,Ga4P2-,Ga5P2-和Ga6P-的基态结构最稳定.     

从头计算对GanNm团簇的结构与稳定性的研究

用B3LYP-DFT方法对GanN2(n=1~7)和GanN(n=2~8)团簇的结构与稳定性进行了研究.在6-31G*水平上进行了结构优化和频率分析,得到了GanN2(n=1~7)和GanN(n=2~8)团簇的基态结构.在GanN(n=2~8)团簇的基态几何结构中,N原子处在分子结构的中心;在GanN2(n=1~3)团簇中,N—N键比Ga—N键强;在GanN2(n=4~7)团簇中存在Ga3N单元和Ga4N单元.在GanN2(n=1~7)和GanN(n=2~8)团簇中,Ga4N2,Ga6P2,Ga3N,Ga5N和Ga7N较其它团簇稳定.     

132，134，136，137Ba（n，p）、132，134Ba（n，2n）反应截面测量

本文叙述１４．２±０．１ＭｅＶ中子能量的１３７Ｂａ（ｎ,ｐ）１３７Ｃｓ、１３６Ｂａ（ｎ,ｐ）１３６Ｃｓ、１３４Ｂａ（ｎ,ｐ）１３４Ｃｓ、１３２Ｂａ（ｎ,ｐ）１３２Ｃｓ、134Ｂａ（ｎ,２ｎ）１３３Ｂａ和１３２Ｂａ（ｎ,２ｎ）１３１Ｂａ等反应截面的测量,测量方法采用以５４Ｆｅ（ｎ,ｐ）５４Ｍｎ和５４Ｆｅ（ｎ,ａ）５１Ｃｒ反应为标准截面的相对活化法,并用现有的数据对本结果进行了比较． The cross sections of the 137Ba (n, p) 137Cs, 136Ba (n, p)136Cs, 134Ba (n, p ) 134Cs, 132Ba (n, p) 132Cs, 134Ba(n, 2n) 133Ba and 132Ba(n, 2n ) 131Ba reactions have been measured by using the activation method relative the cross sections of 54Fe(n, p ) 54Mn and 54Fe(n,a)51Cr reactions at the neutron energy of 14. 2 ±0. 1MeV. The results obtained are compared with the data on hand.     

Measurement of Some (n,2N) Reaction Cross Sections for Producing Long Half-Life Residues

Measurement of (n,2n) reaction cross sections for some nuclides,whose residues have long half-lives,is described.The activation method relative to the ⁹³Nb(n,2n)^92mNb reaction cross section was used.The cross sections of the ¹⁵¹Eu(n,2n)^150mEu、¹⁵³Eu(n,2n)¹⁵²Eu、¹⁵⁹Tb(n,2n)¹⁵⁸Tb and ¹⁰⁹Ag(n,2n)^108mAg reactions in the neutron energy range of 13.50—14.80MeV were measured.The neutron energies in this experiment were determined by means of the method of cross section ratios for ⁹⁰Zr(n,2n)^89m+gZr and ⁹³Nb(n,2n)^92mNb reactions.The results obtained were compared with other existing data.     

Sin-1N和Sin-2N2(n=3～8)离子团簇结构及其光电子能谱的研究

利用密度泛函理论中的B3LYP方法,在6-311G(d)基组上对Sin-1N和Sin-2N2(n=3~8)阴阳离子团簇的几何结构和光电子能谱进行了系统研究。结果得到了各团簇的最稳定结构,Sin-2N2离子团簇对称性比Sin-1N离子团簇对称性好;Sin-1N(n=3~8)离子团簇的几何结构在总原子数n≤4时为平面结构,n>4时为立体结构;Sin-2N2(n=3~8)离子团簇的几何结构在总原子数n≤6时为平面结构,n>6时为立体结构;对于Sin-1N 团簇,总原子数是偶数的团簇比总原子数为奇数的团簇稳定;对于Sin-1N-及Sin-2N2阴阳离子团簇,总原子数是奇数的团簇比总原子数为偶数的团簇稳定。     

含O3MoS3单元的配合物[Mox（CO）y（O,S—C6H4—1,2）3FezLm[^n—（x=1,2或3,y=0,3

用红外光谱研究标题配合物的结构,得到了很有意义的结果。     

激发态H2(X1∑+g,v=1,J=1)之间的碰撞能量合并

受激拉曼激发H2(0,1)基态的Q支得到H2(1,1)能级.在室温条件下,利用反斯托克斯拉曼散射(CARS)探测技术测量了碰撞能量合并(EP)过程H2(1,1)+H2(1,1)→H2(2,J)+H2(0,J″)及H2(1,1)与H2(1,J)转动能级间的碰撞转移速率系数.扫描CARS谱表明在H2(1,1)能级的碰撞能量...     

ZnSe小团簇结构稳定性和电子性质研究

文章研究了小尺寸的(ZnSe)n团簇(n=2-16)的结构和电子性质.通过手工搭建得到团簇结构,用DMol软件包进行结构优化和能量计算,最后分析计算结果 .研究结果表明,对于n=2-4,平面环状结构的能量最低;对于n=5,非平面环状结构的能量最低;对于n=6-12,空心笼状结构的能量最低;对于n=13,核-壳笼状结构的能量最低;对于n=14-16,依旧是空心笼状结构的能量最低.通过分析(ZnSe)_n团簇(n=2-16)的电子性质,我们可以得到,(ZnSe)_9团簇、(ZnSe)_(12)团簇具有很好的稳定性.     

A formula used to subtract the effect of gamma-ray of the others to that of measured reaction in measurement of cross section of nuclear reaction and its application

Abstract According to the regulation of growing and decay of artificial radioactive nuclide, a formula used to subtract the effect of characteristic γ-ray of the others to that of measured reaction was deduced. And then the cross sections of 120Te (n, 2n)119mTe reaction induced by neutrons around 14 MeV were measured by activation relative to the 93Nb (n, 2n)92mNb. In the process of the cross sections measured to be calculated, it was subtracted that the effect of characteristic γ-ray of 126Te (n, p)126Sb to that of measured 120Te (n, 2n)119mTe reaction using the formula deduced. The experimental results were (689±37) and (750±41) mb at the neutron energies of (13.5±0.3) and (14.6±0.3) MeV, respectively. Measurements were carried out by γ-detection using a coaxial HPGe detector. As samples, spectroscopically pure tellurium powder has been used. The fast neutrons were produced by the T(d, n)4He reaction. The neutron energies in these measurements were determined by the method of cross-section ratios between 90Zr (n, 2n) 89m+gZr and 93Nb (n, 2n) 92mNb reactions.     

利用CARS技术研究激发态Rb2和H2的碰撞转移

利用相干反斯托克斯拉曼光谱(coherent anti-stokes Raman spectroscopy,CARS)探测技术,研究了激发态Rb2与H<,2>间的电子-振转能级的碰撞转移.扫描CARS谱确认了H<,2>分子仅在v=1,J=1,2及v=2,J=0,1,2能级上有布居,用n1,n2,n3,n4,n5分别表示...     

Statistical multi-step compound emission in (n, 2n) reactions

The multi-step compound-emission (MSC) theory has been used to analyse the preequilibrium effects in the neutron-emission spectra and excitation curves of the (n, 2n) reactions. Cross sections for the ¹⁹¹Ir(n, 2n) and ¹⁹³Ir(n, 2n) reactions are reported in the neutron-energy range from 13 MeV to 18 MeV and analysed in terms of combined compound-nucleus and MSC theory.