Effect of Incident Intensity on Films Growth in Pulsed Laser Deposition

Incident intensity, defined by the amount of particles deposited per pulse, is an important parameter in the film growth process of pulsed laser deposition （PLD）. Different from previous models, we investigate the irreversible and reversible growth processes by using a kinetic Monte Carlo method and find that island density and film morphology strongly depend on pulse intensity. At higher pulse intensities, lots of adatoms instantaneously diffuse on the substrate surface, and then nucleation easily occurs between the moving adatoms resulting in more smaller-size islands. In contrast, at the lower pulse intensities, nucleation event occurs preferentially between the single adatom and existing islands rather than forming new islands, and therefore the average island size becomes larger in this case. Additionally, our results show that substrate temperature plays an important role in film growth. In particular, it can determine the films shape and weaken the effect of pulse intensity on film growth at the lower temperatures by controlling the mobility rate of atoms. Our results can match the related theoretical and experimental results.     

在Triton X—100存在下,用2-(5-溴-2-吡啶偶氮)-5-二乙胺基苯酚(5-Br-PADAP)分光光度测定方钍石中的钍

方钍石是钍来源的重要含钍矿物。目前测定钍的含量的方法较多,虽有用5-Br-PADAP测定钍的方法的报导,但未见有在triton X-100存在下,用5-Br-PADAP直接测定方钍石中钍的含量的报导。Triton X-100的存在,使测定的酸度增加,从而增加干扰元素的干扰比;并且增加了络合物的稳定时间。本文采用5-Br-PADAP作显色剂,在氯乙酸-氯乙酸钠缓冲体系中用triton X-100表面活性剂胶束增溶分光光度测定方钍石(人工样品)中钍的含量,获得较满意的结果。在25毫升中,钍的比耳定律范围在0～20微克,摩尔吸光系数为5.2×10~4升·摩尔~(-1)·厘米~(-1),Sandell灵敏度为0.0045微克钍(IV)/厘米~2。我们对两种含量的方钍石人工样品进行了测试,结果良好,回收率在97.3～101.4％之间,此方法可靠,精密度较高,误差符合微量组分的测定要求,我们对样品测定结果表示满意。     

掺铒光纤放大器中上转换过程的影响

掺杂浓度的提高影响了掺铒光纤放大器(EDFA)的性能,对经典Giles模型提出了新的要求。首先研究了高掺杂下铒离子距离较小引起的上转换过程的机理,通过优化速率方程模型分析了上转换过程对EDFA的影响,得出了在泵浦光和信号光远远大于ASE光的假设下泵浦光和信号光沿光纤长度变化的近似表达式,并将该近似分析解与解析解进行了比较。仿真结果表明上转换过程会降低随光纤传输的信号光和泵浦光,影响EDFA的放大性能,并得出了当掺铒浓度大于2.95×1025m-3时,上转换过程的影响不能忽略的结论。     

固定设计下一类半参数回归模型的渐近性质

对固定设计下的一类半参数回归模型yi=xiβ+g(xi)+ei,i=1,2,…,n,综合最小二乘和非参数权函数估计方法,定义了,βg的估计量β∧n,gn∧及误差方差σ2的估计量σ2n∧.在适当条件下,证明它们具有强相合性和p(2)阶平均相合性.模拟的结果表明所得结果具有优良的性质.     

Bayes估计的进一步研究及其Pitman最优性

对线性模型参数,讨论了Bayes估计的Pitman最优性,将已有结果进行了改进,去掉了附加条件,证明了在Pitman准则下,Bayes估计一致优于最小二乘估计(LSE),在此基础上,提出了一种基于先验信息的方差分量估计,通过和基于LSE的方差分量估计作比较,证明了新估计是无偏估计且有更小的均方误差．最后,证明了在Pitman准则下生长曲线模型参数的Bayes估计优于最佳线性无偏估计．     

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??We study the linear quadratic optimal stochastic control problem which is jointly driven by Brownian motion and L\'{e}vy processes. We prove that the new affine stochastic differential adjoint equation exists an inverse process by applying the profound section theorem. Applying for the Bellman's principle of quasilinearization and a monotone iterative convergence method, we prove the existence and uniqueness of the solution of the backward Riccati differential equation. Finally, we prove that the optimal feedback control exists, and the value function is composed of the initial value of the solution of the related backward Riccati differential equation and the related adjoint equation.     

癌痛及其处理对癌症患者生存质量的影响

目的 :探讨癌痛及其处理对癌症患者生存质量的影响。方法 :对 4 8例癌痛患者采用线段分级法(VAS)和 KPS评分法于治疗前后进行评估。结果 :无论是轻度、中度还是重度疼痛 ,均严重影响患者的日常生活、情绪、行走能力、工作、睡眠 ,且随着疼痛程度的加重 ,影响也逐渐加深 ;经三阶梯止痛法治疗后生存质量明显提高 ,治疗前后比较有显著的差异 (P<0 .0 5 )。结论 :疼痛是影响癌症患者生存质量的一个重要因素 ,对癌痛患者应给予必要的止痛治疗 ,以提高患者的生存质量     

Spectroscopic and Structural Study of the 1：2 Aluminium（Ⅲ） Complex of Quercetin

Complex formation between aluminium and quercetin（Q） in methanol was investigated by means of 27^Al solid-state, 13^C and 1^H NMR and MS（ESI）, UV and IR spectra. Formation of the 1：2 complex was favored in methanol relative to all other solvent and the predominant species observed of Al（Ⅲ） has a 1：2 stoichiometry. The fine structure of 1：2 aluminum complex of quercetin was that the aluminum central atom chelated with two quereetin molecules and two methoxyl groups between two five membered rings, its coordination is six, the chelated site was 3-hydroxy-4-carbonyl.     

Isomorphisms of fiber spaces over Teichmüller spaces

We will be mainly concerned with some important fiber spaces over Teichmuller spaces, including the Bers fiber space and Teichmuller curve, establishing an isomorphism theorem between "punctured" Teichmuller curves and determining the biholomorphic isomorphisms of these fiber spaces.     

新型含氧亚甲基和亚胺桥键液晶化合物分子结构与光谱的密度泛函理论研究

采用密度泛函理论方法在B3LYP/6-31G*水平上对6个新型含氧亚甲基和亚胺桥键液晶化合物分子的几何结构进行优化计算,讨论了取代基H,CH3,CH3O,C2H5O,NO2,Cl对分子电荷、前线轨道能量和电子吸收光谱等性质的影响.在此基础上使用含时密度泛函理论方法计算了分子第一激发态的电子垂直跃迁能,得到最大吸收波长λmax.计算表明,取代基的引入导致最大吸收波长红移.