附加压力与分散系统的稳定性

较详细地讨论了附加压力与分散系统稳定性间的关系,指出分散相附加压力的降低是分散系统趋向稳定的根本原因。以乳状液为例,附加压力降低不仅减少了液滴间相互碰撞的概率,而且更重要的是,它与液滴表面形成牢固的保护膜密切相关。只有当液滴的附加压力趋近0时,分散系统才达到热力学上稳定的状态,此时乳状液已变成了微乳状液。上述讨论也基本适用于固/液分散系统。     

沉积温度对硬质合金表面沉积的SiC薄膜的影响

采用强电流直流伸展电弧等离子体CVD技术,以Ar、H2和四甲基硅烷(TMS)为先驱气体,在YG6硬质合金衬底表面制备了SiC薄膜。实验结果表明:随着沉积温度的升高,薄膜的致密性和平整度提高;但当沉积温度过高时,SiC薄膜的表面开始具有含非晶碳球和呈花瓣状的疏松结构。在合适的沉积温度下,SiC薄膜的致密性和平整度较好,且其具有较好的附着力和一定的强度,而这样的SiC薄膜可以阻止在金刚石涂层沉积过程中硬质合金中含有的Co对金刚石相沉积过程的有害作用。     

An improved evaluation of the neutron background in the PandaX-Ⅱ experiment

In dark matter direct detection experiments,neutron is a serious source of background,which can mimic the dark matter-nucleus scattering signals.In this paper,we present an improved evaluation of the neutron background in the PandaX-II dark matter experiment by a novel approach.Instead of fully relying on the Monte Carlo simulation,the overall neutron background is determined from the neutron-induced high energy signals in the data.In addition,the probability of producing a dark-matter-like background per neutron is evaluated with a complete Monte Carlo generator,where the correlated emission of neutron(s)andγ(s)in the(α,n)reactions and spontaneous fissions is taken into consideration.With this method,the neutron backgrounds in the Run 9(26-ton-day)and Run 10(28-ton-day)data sets of PandaX-II are estimated to be(0.66±0.24)and(0.47±0.25)events,respectively.     

Recent research progress in wettability of colloidal crystals

The wettability of solid surfaces has attracted extensive interest in both theoretical research and industrial applications. This paper reviews recent research progress in the fabrication and applications of the colloidal crystals with special wettability. Based on the modified equation of Wenzel and Cassie, the colloidal crystals with special wettability have been obtained by either application of the intrinsic rough structure or modification of the surface chemical composition. Some typical applications o...     

吲哚/吲唑酰胺类合成大麻素检验方法研究进展

合成大麻素作为滥用最广泛、种类最多的新精神活性物质之一,严重影响人类身心健康和社会稳定,当前滥用较为严重,常出现在国内外各类案件的侦办中,是世界范围内关于新精神活性物质案件的一个研究焦点,建立合成大麻素的检验方法对侦破相关案件具有重要意义。近几年出现的吲哚/吲唑酰胺类合成大麻素被称为第八代合成大麻素,其涉案频繁但研究相对较少。本文介绍吲哚/吲唑酰胺类合成大麻素的结构、分类、毒性,并对其代谢和检验研究现状进行了综述,同时介绍了检测吲哚/吲唑酰胺类合成大麻素的探索思路,并对未来的发展方向进行了展望。     

Knockout reaction mechanism studied by 6He projectile

Knockout reaction experiment was carried out by using the ⁶He beams at 61.2 MeV/u impinging on a CH₂ target. The α core fragments at forward angles were detected in coincidence with the recoiled protons at larger angles. From this exclusive measurement the valence nucleon knockout mechanism and the core knockout mechanism can be distinguished by the relation between the polar angles of the core fragments and the recoiled protons, respectively. It is demonstrated that the core knockout mechanism may result in some strong contamination to the real invariant mass spectrum.

     

Ni-Zr非晶合金晶化的透射电子显微镜研究(Ⅰ) ——Ni67Zr33晶化过程中的亚稳相

利用透射电子显微镜对Ni₆₇Zr₃₃非晶合金晶化的研究发现了两个新的亚稳相T₀与T₁0。其中T₁相为体心正交(准四方〕晶体,点阵常数a≌b=0.89nm,c=3.14nm,空间群为Iba2或Ibam。温度升高,T₁相转变为含有大量错排的A心正交Ni₁₀Zr₂相,用1/2(a+b)位移错排模型可以圆满地解释其电子衍射图中仅h+k为奇数的衍射斑沿c^*方向拉长的现象,晶化稳定相为Ni₁₀Zr,与Ni₂₁Zr₈(Ni₅Zr₂)相。 关键词：     

厚针孔成像实时监测高能加速器束斑系统

为了方便地测量封有内靶的高能电子加速器束斑,采用了一种基于厚针孔成像技术的动态监测系统.本文给出了采用该系统在15MeV电子直线加速器束流打靶后的束斑测试结果,并简要介绍了成像原理和处理办法.通常的“三明治”方法需要冲洗X光胶片,整机调试时更要多次冲洗,效率较低.与之相比厚针孔成像方法可以实时成像,配合调机及时观察束斑的变化情况,使加速器参数调整有的放矢,提高了调机效率.     

具有空间扩散和年龄结构竞争模型的正平衡态

讨论了具有空间扩散和年龄结构的竞争模型在Neumann边界条件下正常数解的稳定性,并用两种不同的方法给出了非常数正解不存在的条件,即在此条件下不会发生斑图现象.     

聚合物-溶剂相互作用参数研究

根据液体混合的通用Gibbs自由能模型,导得了一个能满意地描述高分子溶液中聚合物-溶剂相互作用参数随浓度和温度变化的方程。它由焓贡献和熵贡献两部分组成,在形式上与Koningsveld-Kleintijen关系式相同,但它的熵贡献是浓度的复杂函数,而不象Koningsveld建议的是一个随意的常数。该方程能够很好地解释高分子溶液的某些特性。