Activation cross-sections of titanium isotopes at neutron energies of 13.5–14.8 MeV

The cross-sections for ~(46) Ti(n,2 n)~(45) Ti, ~(46) Ti(n,p)~(46 m+g) Sc+~(47) Ti(n,d*)~(46 m+g) Sc, ~(46)Ti(n,p)~(46 m+g) Sc, ~(47) Ti(n,p)~(47) Sc+~(48) Ti(n,d*)~(47) Sc, ~(47) Ti(n,p)~(47) Sc, ~(48) Ti(n,p)~(48) Sc+~(49) Ti(n,d*)~(48) Sc,~(48) Ti(n,p)~(48) Sc, and ~(50) Ti(n,α)~(47) Ca reactions were investigated around neutron energies of 13.5–14.8 Me V by means of the activation technique. Fast neutrons were produced by the~3 H(d,n)~4 He reaction. Neutron energies from different directions in the measurements were obtained in advance using the method of cross-section ratios for ~(90) Zr(n,2 n)~(89 m+g) Zr and ~(93) Nb(n,2 n)~(92 m) Nb reactions. The results obtained are analyzed and compared with the experimental data provided by the literature and verified nuclear data in the JEFF-3.3,CENDL-3.1, ENDF/B-VIII.0 libraries, as well as results calculated by Talys-1.9 code.     

几个(n,d~*),(n,t)和(n,n′α)反应截面的测量

本文报告了En～14MeV中子以~(27)Al(n,a)~(24)Na或~(93)Nb(n,2n)~(92m)Nb反应截面为中子注量标准测得的~(92)Mo(n,d~*)~(91m)Nb,~(106)Cd(n,d~*)~(105)Ag;~(54)Fe(n,t)~(25m+g)Mn,~(58)Ni(n,t)~(56)Co;~(51)V(n,n'a)~(47)Sc和~(92)Mo(n,n'a)~(88)Zr的反应截面。文中还列举了能收集蓟的数据以作比较,中子能量是用铌锆截面比法测定的。     

Co-Al-W基高温合金的团簇成分式

Co-Al-W基高温合金具有类似于Ni基高温合金的γ+γ'相组织结构.根据面心立方固溶体的团簇加连接原子结构模型,Ni基高温合金的成分式即最稳定的化学近程序结构单元可以描述为第一近邻配位多面体团簇加上次近邻的三个连接原子.本文应用类似方法,首次给出了Co-Al-W基高温合金的团簇成分式.利用原子半径和团簇共振模型,可计算出Co-Al-W三元合金的团簇成分通式,为[Al-Co_(12)](Co,Al,W)_3,即以Al为中心原子、Co为壳层原子的[Al-Co_(12)]团簇加上三个连接原子.对于多元合金,需要先将元素进行分类:溶剂元素——类Co元素Co (Co, Cr, Fe, Re, Ni,Ir,Ru)和溶质元素——类Al元素Al (Al,W,Mo, Ta,Ti,Nb,V等);进而根据合金元素的配分行为,将类Co元素分为Co~γ(Cr, Fe, Re)和Co~(γ')(Ni, Ir, Ru);根据混合焓,将类Al元素分为Al, W (W, Mo)和Ta (Ta, Ti, Nb, V等).由此,任何多元Co-Al-W基高温合金均可简化为Co-Al伪二元体系或者Co-Al-(W,Ta)伪三元体系,其团簇加连接原子成分式为[Al-Co_(12)](Co_(1.0)Al_(2.0))(或[Al-Co_(12)] Co_(1.0)Al_(0.5)(W,Ta)_(1.5)=Co_(81.250)Al_(9.375)(W,Ta)_(9.375) at.%).其中,γ与γ'相的团簇成分式分别为[Al-Co_(12)](Co_(1.5)Al_(1.5))(或[Al-Co_(12)] Co_(1.5)Al_(0.5)(W,Ta)_(1.0)=Co_(84.375)Al_(9.375)(W,Ta)_(6.250) at.%)和[Al-Co_(12)](Co_(0.5)Al_(2.5))(或[Al-Co_(12)] Co_(0.5)Al_(0.5)(W, Ta)_(2.0)=Co_(78.125)Al_(9.375)(W,Ta)_(12.500)at.%).例如,Co_(82)Al_9W_9合金的团簇成分式为[Al-Co_(12)]Co_(1.1)Al_(0.4)W_(1.4)(～[Al-Co_(12)]Co_(1.0)Al_(0.5)W_(1.5)),其中γ相的团簇成分式为[Al-Co_(12)]Co_(1.6)Al_(0.4)W_(1.0)(～[Al-Co_(12)]Co_(1.5)Al_(0.5)W_(1.0)),γ'相的团簇成分式为[Al-Co_(12)]Co_(0.3)Al_(0.5)W_(2.2)(～[AlCo_(12)]Co_(0.5)Al_(0.5)W_(2.0)).     

R_(13)Fe_(74)Si_(13)三元合金的结构与磁性

本文对R_(13)Fe_(74)Si_(13)(R=Ce,Pr,Nd,Gd,Tb,Dy,Ho,Er,Y)三元合金的结构和磁性进行了研究。结果表明,R_(13)Fe_(74)Si_(13)的主相为R_2(Fe_(0.85)Si_(0.15)_(17)赝二元金属间化合物,而不出现类似于R_2Fe_(14)B的三元金属间化合物。Si原子可能择优取代R_2Fe_(17)中的Fe原子(Th_2Zn_(17)中的9d位或Th_2Ni_(17)中的6g位)。R_(13)Fe_(74)Si_(13)的居里温度比相应的R_2Fe_(17)有所提高。观察了R_(13)Fe_(74)Si_(13)的饱和磁化强度以及室温下的各向异性。本文还从多晶样品磁矩变化模型,根据提拉样品法的低温测量结果,初步定性地分析了R_(13)Fe_(74)Si_(13)低温下磁结构的变化。     

1980年7月—12月原子光谱文献分类索引

一一f一一一一一一一了文献题录8134一8590的分类索引。按应用分类和按元素字母顺序分类。 应用分类索引农业植物一8169(Pb),5216又AI),521了,5236(As, Sb),8285,8286(Ca.K,Mg,P),829组(AI, Ba,Be,Ca,Cd,Cr,Cu,Fe,Mn,P,pb,Sr, Zn),8310,8391(Ag,AI,Ba,Co,Cr,Cu, Fe,Mg,Mn一Mo,Ni,51,Sn,Sr,Ti,V, Zn),8396(CI),8406(Ge),8419(Sb), 8482(K),8516,8554,5573(Cd,Co,Cr, Cu,Ni,孙,Zn),8579(Cd)土壤一8151(Pb),8155(AI,Fe),8233(Mn), 8255(Ca,K,Mg,P),8266(Hg),8271(Cd, Pb),8274(Cu,Fe,Mn,Zn),8296(Ca,K, Mg,P),830…     

Author Index to Volume B2, 1992

h,Jintao一(3),193 h,Jinxing—(2),97 Fan,Haming一(6)石21Chen,Chungtian(l),33 Fan,Pinzhong、(3),229;(6),509Ch*n,**-g-fang一(),39Fel,Lin一(2),139;(5),447Ch*n,F.一(6),533 F*正oher,A.一(6),549Chen,Fang(5),409 Fu,C.H.(5),455Chen,Gaoting(5),385 Fu,Iyung(6),497Chen,Hongbin、(5),399 Fu,Sizu、(6),481C卜*n,H***s*h*一(6),557 Fu,Y***ha*s一(2)J89Chen,Jianwen一(1),71 Fu,Zuliang一(4),289Chen,Jinfeng一(豆),91 Gan,Fuxi一(正),67Chen,Jinkai一(2),155 Gao,Junyi一(5),393,399;(6)石03Chen,S.C.一(l),6…     

Cross-section measurement for Ni（n,x）^58（m＋g）Co, Ni（n, x）^60mCo, Ni（n,x）^61Co and Ni（n,x）^62mCo reactions induced by neutrons around 14 MeV

The cross sections of Ni(n,x)~(58(m g))Co,Ni(n,x)~(60m)Co,Ni(n,x)~(61)Co and Ni(n,x)~(62m)Co reactions induced by neutrons around 14 MeV were measured in this work and calculated by a previously developed formula in this work.The neutron flux was determined using the monitor reaction ~(27)Al(n,α)~(24)Na and the neutron energies were measured with the method of cross-section ratios for ~(90)Zr(n,2n)~(89)Zr to ~(93)Nb(n,2n)~(92m)Nb reactions.     

~(186)W(d,p)~(187)W,~(186)W(d,2n)~(186)Re,~(nat)Fe(p,x)~(56)Co和~(nat)Ti(a,x)~(51)Cr反应激发函数评价

考虑特征γ射线分支比、衰变常数和标准截面等修正,对带电粒子引起的核反应~(186)W(d,p)~(187)W,~(186)W(d,2n)~(186)Re,~(nat)Fe(p,x)~(56)Co和~(nat)Ti(a,x)~(51)Cr的激发函数进行了研究。全面收集了这些反应激发函数的实验测量数据,对这些实验数据进行了分析处理,应用数学方法对分析处理后的实验数据进行了拟合。经过评价,给出了50 Me V以下~(186)W(d,p)~(187)W,~(186)W(d,2n)~(186)Re,~(nat)Fe(p,x)~(56)Co和~(nat)Ti(a,x)~(51)Cr反应激发函数的推荐值。     

间隙原子H,B,C对LaFe_(11.5)Al_(1.5)化合物磁性和磁热效应的影响

研究了金属化合物LaFe_(11.5)Al_(1.5)H_x(x=0,0.12,0.6,1.3),LaFe_(11.5)Al_(1.5)B_y(y=0.1,0.2,0.3)和LaFe_(11.5)Al_(1.5)C_z(z=0.1,0.2,0.3,0.4,0.5)的磁性、结构和磁热效应.金属化合物样品均形成了良好的NaZn_(13)型单相结构.基于固相-气相反应或者固相-固相反应引入间隙H,B,C原子后,磁性基态从反铁磁态变为铁磁态,饱和磁化强度(M_s)和居里温度(T_c)均呈升高趋势.值得注意的是:随着B和C含量的增加,化合物的相变性质由弱一级相变过渡至二级相变;而随着H含量的增加,相变性质却从二级相变过渡至弱一级相变.同时,化合物LaFe_(11.5)Al_(1.5)H_x,LaFe_(11.5)Al_(1.5)B_y和LaFe_(11.5)Al_(1.5)C_z均呈现出相当大的磁熵变.在0—5 T的外磁场作用下,LaFe_(11.5)Al_(1.5)H_(1.3),LaFe_(11.5)Al_(1.5)B_(0.1)和LaFe_(11.5)Al_(1.5)C_(0.2)的最大磁熵变分别达到12.3,9.6和10.8 J/kg·K.此外,在0—5 T的外磁场作用下,LaFe_(11.5)Al_(1.5)H_(0.6)的制冷能力达到259.2 J/kg,LaFe_(11.5)Al_(1.5)B_(0.1)的制冷能力达到116.4 J/kg,而LaFe_(11.5)Al_(1.5)C_(0.1)的制冷能力达到230.4 J/kg.     

Predictions of decay modes for the superheavy nuclei most suitable for synthesis

The competition between α-decay and spontaneous fission of superheavy nuclei(SHN) is investigated by the generalized liquid drop model(GLDM) and the modified Swiatecki's formula respectively. The theoretical decay modes are in good agreement with the experimental results. Predictions are made for as-yet unobserved superheavy nuclei. The theoretical calculations show that the nuclei~(298)120,~(295)119,~(290)118,~(291)117,~(287)117,~(294)116,~(289)116,~(286)116,~(285)116,~(284)115,~(283)115,~(283)114,~(282)114,~(280)113,~(276)112,~(275)112,~(274)112,~(273)111,~(272)110,~(265)109 may be synthesized experimentally in the near future since they not only have relatively large predicted cross sections but can also be identified via α-decay chains.     

纳米Ce_(0.95)M_(0.05)O_2(M=Fe,Nd, Eu)光谱特征及其催化性能研究

采用水热法制备纳米Ce_(0.95)M_(0.05)O_2(M=Fe~(3+),Nd~(3+),Eu~(3+))固溶体,系统研究了固溶体的微观晶体结构及光谱特性。X射线衍射(XRD)结果表明,掺杂样品均为单相萤石立方结构,无对应于掺杂离子氧化物的杂相存在,说明三种掺杂离子均成功掺入CeO_2晶格内而形成固溶体。计算各样品的晶粒尺寸,得到掺杂固溶体的粒度均低于20 nm。采用紫外可见光谱(UV-Vis)表征固溶体的电子跃迁性能。与纯CeO_2相比,掺杂固溶体的吸收边均发生红移;同时,拟合得到各样品能隙由大到小依次为:CeO_2(3.13 eV)Ce_(0.95)Eu_(0.05)O_2(3.04 eV)Ce_(0.95)Nd_(0.05)O_2(2.94 eV)Ce_(0.95)Fe_(0.05)O_2(2.75 eV)。荧光光谱(PL)测试表明,掺杂样品的发射峰强度均比纯CeO_2低,其中Fe~(3+)掺杂固溶体样品的荧光强度降低最为明显。其原因在于Fe~(3+)掺杂会使固溶体晶格内引入更多缺陷,从而阻碍了电子与空穴的复合。将固溶体作为催化剂添加到Mg_2Ni-Ni中,球磨制得Mg_2Ni-Ni-5%Ce_(0.95)M_(0.05)O_2复合材料,系统测试复合材料电极的电化学和动力学储氢性能。结果表明, Ce_(0.95)M_(0.05)O_2固溶体可有效提高Mg_2Ni-Ni合金复合材料的电化学放电性能,最大放电容量分别为:Ce_(0.95)Fe_(0.05)O_2(874.8 mAh·g~(-1))Ce_(0.95)Nd_(0.05)O_2(827.8 mAh·g~(-1))Ce_(0.95)Eu_(0.05)O_2(822.7 mAh·g~(-1))CeO_2(764.9 mAh·g~(-1))。同时,催化剂还可有效提高复合材料的电化学循环稳定性,经20次循环后的容量保持率为:Ce_(0.95)Fe_(0.05)O_2(49.8%)Ce_(0.95)Eu_(0.05)O_2(49.7%)Ce_(0.95)Nd_(0.05)O_2(46.3%)CeO_2(34.1%)。对复合材料进行高倍率放电性能(HRD)表征,掺杂固溶体催化剂能够显著提高样品的大电流放电性能,如当放电电流密度为200 mAh·g~(-1)时,各样品的HRD为:Ce_(0.95)Fe_(0.05)O_2(59.5%)Ce_(0.95)Eu_(0.05)O_2(57.4%)Ce_(0.95)Nd_(0.05)O_2(55.7%)CeO_2(54.4%)。采用恒电位阶跃测试催化剂对复合材料中H扩散能力的影响, H扩散系数由大到小依次为Ce_(0.95)Fe_(0.05)O_2Ce_(0.95)Eu_(0.05)O_2Ce_(0.95)Nd_(0.05)O_2CeO_2。分析认为,固溶体的催化效果与其氧空位浓度、晶格缺陷及掺杂离子易变价特性密切相关。     

六角柱形NaErF_(4)和NaErF_(4)@NaYF_(4)核壳微粒制备及多色上转换荧光调控性能EI北大核心CSCD

采用简单的水热法合成了六角柱形NaErF_(4)和NaErF_(4)@NaYF_(4)核壳上转换发光材料,利用扫描电镜(SEM)、X射线粉末衍射(XRD)和荧光光谱(PL)等表征对材料的形貌、结构和上转换发光性能进行了研究。结果表明,纯NaErF_(4)样品为六角柱形,边长和厚度均为1μm左右,样品表面光滑。随着NaYF_(4)壳层的包覆,六角相NaErF_(4)周围出现了大量的立方相NaYF_(4)纳米颗粒,得到了NaErF_(4)@NaYF_(4)核壳结构。荧光光谱表明,通过在六角柱形NaErF_(4)表面包覆NaYF_(4)壳层,可以有效增强上转换发光强度,其中,位于527,543,663 nm处的3个发射峰分别对应于Er^(3+)的^(2)H_(11/2)→^(4)I_(15/2)、^(4)S_(3/2)→^(4)I_(15/2)和^(4)F_(9/2)→^(4)I1_(5/2)能级跃迁。随着壳层中Y∶F比例的增加,立方相NaYF_(4)的晶体衍射峰逐渐增强;同时,对应的NaErF_(4)@NaYF_(4)样品发射光谱中红绿比(R/G)逐渐增大,发光颜色也从绿色、经黄绿色逐渐向黄色过渡,实现了多色发光。     

Sr原子自电离谱线的观察和分析

本文报道了用偏振光束分步激发的方法,对Sr原子(5p_(1/2~(ns)))_(J-1)及(5P_(1/2~(nd))_(J-1,3)自电离谱的观察,测定了Sr的(5P_(1/2~(ns))_(J-1)系列(n=10～26)的自电离能级位置和量子亏损,并对(5P_(1/2~(ns))_(J-1)及(5P_(1/2~(nd))_(J-1,3)两种自电离谱线的不同特点进行了分析.     

~(50,48,46)Ti的(n,p)(n,α)和~(58)Ni的(n,2n)(n,p)反应截面的测量

本文叙述了从13.50 MeV到14.81 MeV中子能区用活化法相对~(21)Al(n,α)~(24)Na的反应截面,对~(50)Ti(n,α)~(47)Ca、~(48)Ti(n,p)~(48)Sc、~(46)Ti(n,p)~(46)Sc、~(58)Ni(n,2n)~(57)Ni、~(58)Ni(n,p)~(58m+g)Co五个反应截面的测量。并将所得的结果和其他作者的结果进行了比较。     

s,d,g玻色子相互作用中的三种极限

在I.B.M中,当存在s,d,g玻色子时,玻色Hamiltonian具有U(15)群结构,本文讨论了U(15)群的各种子群链,特别详细研究了子群链 SU(15)?SU(3)?SO(3), SU(15)?SU(5)?SO(5)?SO(3), U(15)?U(14)?SO(5)?SO(3)。同时给出了能谱公式。     

~(13)Cu、~(65)Cu和~(15)N标记的二(2-羟基苯乙酮肟)—铜(Ⅱ)配合物的ESR波谱研究

本文解析了同位素标记的~(63)Cu-~(14)N-HAP,~(65)Cu-~(14)N-HAP,~(63)Cu-~(15)N-HAP。~(65)Cu-~(15)N-HAP,和Cu-~(15)N-HAP,等五种配合物在四氢呋喃中,在77K温度下测得的分辨较好的ESR波谱。从图上不仅得到了~(63)Cu和~(63)Cu的超精细分裂,而且还得出分辨较好的~(14)N和~(15)N的超超精细分裂。比较合理地确定了g_x,g_y,g_z;A_x~(65),A_y~(65),A_z~(65)和A_x~(63),A_y~(63),A_z~(63)以及A_∥~(15),A_⊥~(15)和A_∥~(14),A_⊥~(14)等张量参数。利用测得的波谱参数计算了键参数,并讨论了配合物的电子结构及成键特性,得到了较满意的结果。     

铕与4-(4-吡啶甲酰基)苯甲酸配合物的合成与荧光性能研究

以Eu3+为中心离子,4-(4-吡啶甲酰基)苯甲酸(HPFBA)、1,10-菲罗啉(Phen)和三苯基氧膦(TPPO)为配体,合成了新型配合物Eu(PFBA)3(H2O)4,Eu(PFBA)3Phen(H2O)3和Eu(PFBA)3TPPO(H2O)3(PFBA=4-(4-吡啶甲酰基)苯甲酸根).红外光谱表明,形成配合...     

提高内燃机热效率的一条有效途径——余热回收内循环加力

目前,内燃机的热效率不高,它主要由一系列的(火用)损失引起.在内燃机里,燃料的(火用)损失E_(xl)为:E_(xl)=E_(xl_1)+E_(xl_2)+E_(xl_3)+E_(xl_4)+E_(xl_5) (1)式中:E_(xl_1)——燃料化学反应的(火用)损失;E_(xl_2)——冷却水带走的(火用)损失;E_(xl_3)——由活塞、缸壁等传热、摩擦向环境散失热量的(火用)损失;E_(xl_4)——废气(火用)损失;E_(xl_5)——燃气热量传给冷却介质,由于两者温差产生的不可逆(火用)损失.其中燃料燃烧(化学反应)转换过程的(火用)损失率为:     

3M_⊙ AGB星中~(26)Al核合成的网络计算和反应率灵敏度分析（英文）

研究了3 M_☉AGB星中~(26)Al核合成的网络计算和核反应率的灵敏度分析。结合最新的核反应率数据,建立了一个从碳到硅完整的核反应网络,计算了 ~(26)Al的丰度。结果表明,~(26)Al首先在AGB星中有效合成,随着核反应的进行,然后被一系列的核反应消耗。MgAl循环出现在~(26)Al的网络中。我们将核反应网络中的主要核反应分为三类:(n,γ),(p,γ)和(α,γ),并对核反应率的灵敏度进行了详细的分析。已经确定了每一类中最有影响的核反应,它们是 ~(25)Mg(n,γ)~(26)Mg,~(25)Mg(p,γ)~(26)Al,~(26)Mg(p,γ)~(27)Al,~(21)Ne(p,γ)~(22)Na,~(18)O(α,γ)~(22)Ne和 ~(22)Ne(α,γ)~(26)Mg。在目前网络所涉及的所有核反应中,25Mg(p,γ)~(26)Al是对~(26)Al的产量有最大的影响,它值得核实验物理学家的关注。     

Electronic,optical, and mechanical properties of BN,AlN, and InN with zinc-blende structure under pressure

In this work, the electronic, optical, and mechanical properties of BN, AlN, and InN under the action of pressure are calculated. For each of these compounds, the energy band structure, band gaps(E~L_g, E~Γ_g, E~X_g), refractive index(n),dielectric constants(ε_∞, ε_0), elastic constants(C_11, C_12, C_44), and relevant parameters such as bulk(B_u), shear(S_h), and Young's(Y_0) moduli are studied, and other important parameters such as bond-stretching(α), bond-bending(β) force constant, internal-strain parameter(ζ), effective charges(e~*_T, Z~*), anisotropy factor(I_s), Poisson's ratio(P_o), Cauchy ratio(C_a), the ductility index(μ_D), and linear compressibility(C0_) are also calculated. The effects of pressure on all studied properties are investigated. Our results are in good agreement with the available experimental and theoretical data for BN,AlN, and InN.