表面活性剂增敏-火焰原子吸收光谱法测定中草药中微量锶

锶是人体健康所需微量元素之一,现代医学发现,锶缺乏可导致多汗、影响骨密质、白发、抽搦、龋齿等.锶有降低某些类型心血管疾病的死亡率,一般成年人每天需锶1.9 mg的摄入量以保持摄人和排除的平衡,临床上用碘化锶、溴化锶治疗荀麻疹等疾病.     

“老师,我的解法比你的更好!”——记数学试卷讲评课上的一次风波

1背景描述新课程改革在广东已开展多年.2007年9月至今,我在自己任教的两个理科班开展了在高中数学教学中开展数学交流活动的实验研究.在这实验研究中,结合数学新课程改革理念,我不断加强理论学习、反思实验过程,收获颇多:学生的数学学习兴趣大     

椭球模型下通过雾场的多重光散射谱

由于雾滴的非球形、多重散射特性以及几何光学效应,光通过实际雾场的散射问题成为一个研究难点. 建立了近于实际的椭球雾滴模型,考虑光的衍射、透射及反射特性后,利用辐射传播方程得到了在不同的雾滴大小分布 及不同的雾滴形状分布下通过雾场的多重散射光强公式.在两种特例下与已有的结果较为相符,说明了方法的可靠性. 计算表明:与随机取向的非球形颗粒场的散射谱呈圆形特征不同,通过椭球形雾滴场的散射谱呈椭圆特征, 不同方位角的散射光强角分布有所差异,雾滴的形状因子越接近于1,差异越小;与单散射不同, 散射谱中的条纹随光学厚度增大逐步消失;对于不同大小分布及不同形状分布的雾滴场, 在不同方位角及不同观察角的散射光强随光学厚度τ的增加总是先增大再减小,光强的极大值位置在τ = 1.0---3.0 范围内.计算同时还表明,由于多数情况下实际雾场的雾滴大小偏差较大, 因而通过雾场的散射谱将呈现以中央亮斑为中心向四周弥散的图样.     

Angular distribution of ~6He+p elastic scattering

The angular distribution of ¹H(⁶He,p)⁶He elastic scattering has been measured at E_c.m.=4.3 MeV by using a thick-target inverse kinematic method. The experimental differential cross sections are reproduced by the distorted-wave Born approximation calculation utilizing the CH89 global optical potential parameter set. The real part of CH89 is reduced comparing with other potentials, which may be attributed to the couplings necessary for the weakly bound nuclei.     

Excited States in ^18Ne Studied via ^17F＋p

The elastic resonance scattering of ^17F＋p is studied in inverse kinematics via a thick-target method. The excitation function for ^17F＋p elastic scattering is obtained within the energy interval of Ec.m ≈ 0.4-1.7 MeV. The experimental excitation function is analyzed with a multilevel R-matrix code MULTI7, and the proton widths are deduced. The α decay from 6.15 MeV 1- state in 18Ne is observed, which is critical to the 14O（α, p）17F reaction as the main breakout route from CNO cycle to rp-process in supernovae and x-ray bursts.     

PET共混改性研究

综述了国内外PET共混改性的研究现状 ,并介绍了近年来PET共混研究的新发展     

L形通道布线的展开法

本文提出将L形通道展成直通道的布线方法，对展开后的直通道定义了水平约束、垂直约束、拐角约束、走线约束，利用赋权的混合图反映这四种约束、并逐步将图中的无向边转变成有向边，按照有向图的线网上下关系，完成直通道布线，再收缩冗余布线区变成L形通道布线.     

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为了研究等离子体与自由液态锂表面相互作用的物理过程,建立了用氩气驱动的液态锂回路装置。介绍了建立的液态锂回路装置的组成部分、技术参数及运行原理。此回路主要由主回路、等离子体与液态锂相互作用试验段和单阴极高密度等离子体发生装置三部分组成。目前,此回路已取得一些初步的模拟结果和实验结果。     

聚合物纳米复合体系中聚合物结构及动力学研究进展

从计算模拟及实验角度系统总结了聚合物结构、 聚合物构象、 聚合物扩散及聚合物多尺度动力学的研究进展, 阐述了各影响因素及其变化规律, 并对聚合物动力学的未来研究进行了展望.     

Morphological and structural damage investigation of nanostructured molybdenum fuzzy surface after pulsed plasma bombardment

Steady high-flux helium (He) plasma with energy ranging from 50 eV to 90 eV is used to fabricate a fiber-form nanostructure called fuzz on a polycrystalline molybdenum (Mo) surface. Enhanced hydrogen (H) pulsed plasma in a wide power density range of 12 MW/m²-35 MW/m² is subsequently used to bombard the fuzzy Mo, thereby simulating the damage of edge localized mode (ELM) to fuzz. The comparisons of surface morphologies, crystalline structures, and optical reflectivity between the original Mo and the Mo treated with various He⁺ energy and transient power densities are performed. With the increase of He ion energy, the Mo nano-fuzz evolved density is enlarged due to the decrease of filament diameter and optical reflectivity. The fuzz-enhanced He release should be the consequence of crystalline growth and the lattice shrinkage inside the Mo-irradiated layers (~200 nm). The fuzz induced by lower energy experiences more severe melting damage and dust release under the condition of the identical transient H plasma-bombardment. The H and He are less likely to be trapped due to aggravated melting evidenced by the enhanced crystalline size and distinct lattice shrinkage. As the transient power density rises, the thermal effect is enhanced, thereby causing the fuzz melting loss to aggravate and finally to completely disappear when the power density exceeds 21 MW/m². Irreversible grain expansion results in huge tensile stress, leading to the observable brittle cracking. The effects of transient thermal load and He ion energy play a crucial role in etching Mo fuzz during ELM transient events.