Fragmentation in ^16 O-emulsion interactions at 3.7 A GeV

The topology of ¹⁶O fragmentation at 3.7 A GeV in reactions with emulsion nuclei is presented. The multiplicity distributions of projectile fragments,charged secondaries and their dependences on the projectile residues are discussed.     

动态几何问题综述

动态几何问题是近几年中考压轴题的一大亮点,为中考一大特色题型.例1(2003吉林)如图1,矩形ABCD中,AB=10cm,BC=8cm.点P从A出发,沿A→B→C→D运动,到D停止;点Q从D出发,尚D→C→B→A运动,到A停止,两点同时出发,P、Q速度分别为1cm/s、2cm/s.a秒时,两点同时变速,P、Q速度分别变为6cm/s.dcm/s.图2是P出发x秒后△APD面积S1(cm2)与x(秒)的函数图象;图5是Q出发x秒后△AQD面积S2(cm2)与x(秒)函数图象.图1图2(1)参照图2求a,b及图2中c值;(2)求d值;(3)设P离开A的路程为y1;Q到AA还需走y2cm,请写出两点同时变速后,y1,y2关于运动时间x的关…     

把握反馈信息 探寻解题规律——年号趣题解法例析

思维是能力的核心,观察是思维的外壳.解数学题一时也离不开观察、思维.一个命题的整体结构及数字特征,都会反馈出各种各样的信息.如果我们认真观察,科学地捕捉这些信息,进而联想知识,探索规律,则可化难为易,思路畅通,巧妙获得解证。本文以年号趣题为例,试析如下,以供探究.     

百兆电子伏特/核子原子核诱发乳胶核反应靶核反冲质子多重数涨落分析(英文)

利用标度阶乘矩方法对290 A MeV $^{12}$C-AgBr, 400 A MeV $^{12}$C-AgBr, 400 A MeV $^{20}$Ne-AgBr及500 A MeV $^{56}$Fe-AgBr 作用靶核反冲质子在二维正常相空间及累积变量空间发射过程中的多重数涨落分别进行了分析。实验结果表明:在正常相空间,对于秩数q较小时标度阶乘矩（$ln$）随相空间的分割数的增加而增加,而对于秩数较大时标度阶乘矩（$ln$）随相空间的分割数的增加表现出先增加后趋于饱和或减小的趋势;在累积变量空间,标度阶乘矩（$ln$）随相空间的分割数的增加而减小,这表明对于我们所研究的核作用体系靶核反冲质子发射过程中不存在非统计涨落。Multiplicity fluctuation of the target recoil protons emitted in $290$\,A MeV $^{12}$C-AgBr, $400$\,A MeV $^{12}$C-AgBr, $400$\,A MeV $^{20}$Ne-AgBr and $500$\,A MeV $^{56}$Fe-AgBr interactions are studied using the scaled factorial moment (SFM) method in two-dimensional normal phase space and cumulative variable space, respectively. It is found that in normal phase space the SFM ($\ln$) increases linearly with the increase of the divided number of phase space ($\ln{M}$) for lower q-values and increases linearly and then becomes saturation or decrease with the increase of $\ln{M}$ for higher q-values, and in cumulative variable space $\ln$ decreases linearly with the increase of $\ln{M}$, which indicates that no evidence of non-statistical multiplicity fluctuation is observed in our data sets.     

Electromagnetic dissociation of 3.7 A GeV^16O in nuclear emulsion

The electromagnetic dissociation (ED) of 3.7 A GeV {}^{16}O in nuclear emulsion is investigated with high statistics. It is found that the electromagnetically dissociated cross section increases with increasing beam energy, the charge distribution of projectile fragments is the same as the results at 60 and 200 A GeV, and the production probability of projectile fragments with charge 3≤Z≤5 is less than that of the other projectile fragments. These results can be well explained by use of Weizsacker and Williams method for calculating the ED contributions. The percentile abundance of various decay modes for ED at 3.7 A GeV is close to the result at 60 and 200 A GeV, but it is different from the result at 14.6 A GeV. The ED of 3.7 A GeV is mainly caused by the giant dipole and quadrupole resonance of E1 and E2, which can be qualitatively explained by the multiplicity distribution of projectile proton in ED. The multiplicity distribution of the α fragments in ED and nuclear events have different functional forms. This difference may be a consequence of the different reaction mechanism involved.     

Intermittency in 3.7 A GeV ^16O-emulsion interactions

The intermittency effect has been studied for an interaction of 3.7 A GeV ^16O with emulsion using the distributions of both the pseudorapidity intervals and the azimuthal angle intervals of the shower particles emitted in a central rapidity region. The scaled factorial moments, reduced scaled factorial moments and multifractal moments as functions of the bin size in pseudorapidity and in azimuthal angle have been calculated and have revealed the presence of an intermittent behaviour which may be due to the random cascading property of the reaction. The anomalous fractal dimension has been found to increase with the increase of rank of the moment.     

新型含萘基和二乙炔基高双折射液晶分子的合成及光电性能

通过多步Sonogashira偶联反应成功合成分子结构中含萘环的不对称二乙炔衍生物:4-(4-(4-(6-(己氧基)-2-萘基)-1-(1,3-丁二炔基))-3-乙烯基-苯乙炔基)-N,N-二甲基苯胺。 通过核磁共振和元素分析对其结构进行了表征,通过差式扫描量热分析(DSC)、偏光显微镜(POM)和阿贝折射仪研究了其液晶性和双折射特性;通过紫外-可见吸收光谱仪和荧光分光光度计测得其吸收-发射光谱。 测量发现该化合物具有热致型向列相液晶特性和很高的双折射值(Δn=0.47)。 化合物溶液荧光发射波长为470 nm,荧光量子产率高达97%。 应用旋转涂膜的方法制作的双层器件ITO/PEDOT/liquid crystal compound/Mg:Ag(10:1)/Ag(ITO:氧化铟锡,PEDOT:聚3,4-乙撑二氧噻吩),电致发光波长为503 nm,器件显示了较好的电致发光稳定性和二极管整流特性,启动电压较低(6.75 V),在14.75 V时达到最大亮度150 cd/m²。 该化合物有望作为一种潜在的液晶显示材料和电致发光材料。     

对能对弹核碎裂反应截面的影响

运用改进的量子分子动力学(ImQMD)模型嫁接GEMINI统计衰变模型对400 AMeV 36Ar与C、Al、Cu、Pb的弹核碎裂反应截面的奇偶效应进行了理论分析。分析结果表明，弹核碎裂电荷反应截面的奇偶效应产生在初级碎块的退激发过程中，而且退激发过程中的对能在奇偶效应的产生中起着重要作用。如果不考虑对能，弹核碎裂电荷反应截面的奇偶效应将消失。同时由于对能的作用使得弹核碎裂的中子反应截面也表现出明显的奇偶效应。     

溶液蒸发冻结过程中冰体发展的分形模拟研究

根据溶液在蒸发冻结过程中的复杂性以及液面冰体分布的不规则,结合分形有限扩散聚集(DLA)理论,建立了湿度差作用下溶液蒸发冷冻过程中液面冰体生成、发展过程的数学模型,模拟分析了气流湿度差和气流流速对溶液表面冰体生成、发展的影响.结果表明,利用分形方法可以对溶液蒸发冻结过程中冰体的生成发展进行预测,同时也为研究溶液蒸发冻结和冰体生长提供了新的思路和方法.     

Helium production from 84Kr-- and 197Au--emulsion interactions at high energies

The properties of the relativistic helium fragments produced in interactions of 84 Kr at 1.8 A GeV and 197 Au at 10.7 A GeV in emulsion are investigated. The experimental results are compared with those obtained from various projectiles with emulsion collisions at different energies. It is found that the multiplicity distribution of helium projectile fragments (HPFs) is well described by the Koba-Nielsen-Olesen (KNO) scaling presentation. The second Mueller moment f 2 of the HPF multiplicity distribution is independent of the projectile energy for the same projectile, but it is dependent on the projectile mass number. The value of f 2 increases with the increase of projectile mass number A p . The negative value of f 2 , when A p < 69, means that the emission of HPFs is anticorrelated, but positive value of f 2 , when A p > 69, refers to that the emission of HPFs is correlated. The non-zero f 2 moment in this experiment implies the strong correlation existing between the HPFs.