8-羟基喹啉快速共沉淀分离富集原子吸收光谱法测定啤酒中的Cu和Pb

研究了用8-羟基喹啉-Mg(Ⅱ)共沉淀体系,以Mn(Ⅱ)为内标,快速共沉淀分离富集啤酒中的铜和铅,并用火焰原子吸收光谱(FAAS)测定的方法。共沉淀受pH值、载体镁和内标锰用量的影响。结果显示在pH为9的条件下,能够定量共沉淀试样中的铜和铅。当试液为100 mL时,方法的检出限分别为铜6.28×10-3 μg·mL-1,Pb 2.26×10-2 μg·mL-1回收率为97.6%～103.0%,基本消除了基体干扰,取得了较为满意的结果。该方法无需收集全部沉淀,与传统的共沉淀方法比较,克服了收集沉淀费时的缺点。方法快速、简便、重现性好。     

基于哈希理论和线性近邻传递反馈的乳腺X线图像肿块检索方法

在乳腺X线图像肿块检测中存在较高的假阳性率,通过基于内容的肿块检索,将待判定肿块与已确诊肿块进行相似性分析,可有效降低假阳性率.本文提出了一种结合可区分锚点图哈希和线性近邻传递的乳腺图像肿块检索方法.针对传统锚点图哈希在相似度定义中没有考虑病理相关性的问题,引入病理类别至锚点图哈希图像相似度计算,提出了可区分锚点图哈希以重新表示图像.利用线性近邻传递作为相关反馈技术,基于图像底层特征表达与图像高层语义间的学习机制,实现交互式肿块图像检索.采用北京大学人民医院乳腺中心提供的临床图像作为实验数据,实验结果表明,引入病理类别的可区分锚点图哈希图像表达在肿块相似性分析上优于传统锚点图哈希.相比于现有方法,本文提出的方法在肿块检索性能上得到明显提高.     

Entropy,Fisher Information and Variance with Frost-Musulin Potenial

This study presents the Shannon and Renyi information entropy for both position and momentum space and the Fisher information for the position-dependent mass Schrödinger equation with the Frost-Musulin potential. The analysis of the quantum mechanical probability has been obtained via the Fisher information. The variance information of this potential is equally computed. This controls both the chemical properties and physical properties of some of the molecular systems. We have observed the behaviour of the Shannon entropy. Renyi entropy, Fisher information and variance with the quantum number n respectively.     

探测器横纹误差对大孔径静态干涉成像光谱仪影响的建模与修正

大孔径静态干涉成像光谱技术在航天遥感应用中,由于探测器横纹误差影响,使获得的干涉数据无法反演光谱数据,需要对横纹误差进行修正。通过对干涉成像机理的分析,给出探测器横纹误差影响下的干涉成像模型,提出横纹误差影响下干涉数据修正方法。最后利用仪器获取的数据,对提出的修正方法进行验证,由处理结果可以看出,本文所提的修正方法可以很好的修正横纹误差对光谱的影响,提高反演光谱的精度。     

质子交换膜燃料电池低化学计量比的性能研究

以质子交换膜燃料电池实际应用为背景,研究了在反应物低化学计量比下,质子交换膜燃料电池不同温度、压力下的性能。得到了电池温度,压力对反应物化学计量比的影响。实验结果表明,反应物化学计量比1.0的电池性能低于足量反应气体工况下的电池性能;化学计量比为1.3时,电池能够在预期电流强度下稳定运行;反应气体的传质过程影响反应所需的化学计量比;当提升压力至0.13 MPa,化学计量比1.0的电池性能与足量反应气体工况下的性能相当。     

传质特性对光纤生物制氢反应器性能的影响

光生物制氢反应器的传质特性是影响反应器特性的重要因素.本文通过构造新型的光纤生物制氢反应器,采用生物膜法细胞固定化技术,考察在连续产氢条件下,进口底物浓度和流速对与反应器产氢相关特性的影响.结果表明:高浓度下出现的底物抑制现象是限制反应器性能的原因;流速改变的传质特性对反应器性能的影响,反映在驱动势和反应时间两个方面.     

Might Dark Matter and Energy be Intrinsic Properties of?Space?

It is shown that if a volume element V, of space is assumed to have intrinsic energy E, then basic principles of mechanics, thermodynamics and special relativity lead to the equation of state: E=pV, where p is the pressure. When this equation of state is incorporated in the Einstein equations it leads to the prediction that the orbital speed of matter circling a visible galaxy embedded in a spherical galactic halo should be relativistic, in disagreement with observations. However, it also leads directly to the interesting notion that the inertial mass of such a medium can be understood as a resistance to being compressed via Lorentz contraction. It is then shown that the mathematical structure of thermodynamics suggests another plausible definition of pressure if we allow for the possibility that the intrinsic energy of spacetime may not be described by the same work-energy relationship as ordinary matter. This additional possibility leads to the equation of state: E=−pV. While both of these equations of state describe forms of energy that are quite unlike ordinary energy, neither alone is able to account for observed rotational velocity curves of matter orbiting visible galaxies. Therefore, the possibility that space has two distinct components of energy is investigated. This results in a plausible, two-component equation of state in which the former equation of state is tentatively identified as the “dark matter” (DM) component, the latter as the “dark energy” (DE) component. The effective equation of state of space, accounting for the presence of both components, may then be written in the form: p=w ε, where ε is the total energy density, p the total pressure, and w represents the fractional excess of DM over DE (and therefore satisfies: −1≤w≤+1). Given the wide range of possible spacetime properties implied by this equation it appears to be a viable candidate for explaining observations presently attributed to the presence of both DM and DE. Specifically, the static, spherically symmetric solution of Einstein’s field equations, neglecting effects of ordinary matter, predicts the inverse r ² distribution of intrinsic space energy required to explain observed constant rotational velocity curves for matter in circular orbits around visible galaxies embedded within spherically symmetric galactic halos. The proposed equation of state is also capable of describing regions of space undergoing accelerated expansion as regions where DE is dominant (i.e., w<−1/3).     

Annular billiards with position-dependent mass

We present exact solutions for the position-dependent mass Schrödinger equation (PDMSE) in an annular billiard with impenetrable walls where the mass is allowed to depend on the radial position, i.e., μ=μ(r)$\mu =\mu \left(r\right)$. Exact wavefunctions are calculated explicitly for four mass distributions.     

Mei Symmetries and Lie Symmetries for Nonholonomic Controllable Mechanical Systems with Relativistic Rotational Variable Mass

The Mei symmetries and the Lie symmetries for nonholonomic controllable mechanical systems with relativistic rotational variable mass are studied. The differential equations of motion of the systems are established. The definition and criterion of the Mei symmetries and the Lie symmetries of the system are studied respectively. The necessary and sufficient condition under which the Mei symmetry is Lie symmetry is given. The condition under which the Mei symmetries can be led to a new kind of conserved quantity and the form of the conserved quantity are obtained. An example is given to illustrate the application of the results.     

X射线荧光光谱法测定增产丙烯助剂中磷和铁的研究

使用X射线荧光光谱仪,采用人工合成标样,设计合成了一套标准样品,采用数学校正法中的经验系数法校正元素间的互相干扰,样品不经任何处理,粉末直接压片,经验系数法校正基体效应,建立了分析测定增产丙烯助剂中磷和铁含量的方法。讨论了样品制作方法,合适的测量条件,探讨了试样中元素间的相互影响。实验结果表明,该方法重现性好,准确度和精密度较高,测定磷和铁的相对标准偏差为：0.34%和0.59%;测定范围磷为0.01%～2.5%,铁为0.01%～2.5%。分析结果与化学法、等离子发射光谱法测定结果吻合。该方法快速、简便,样品处理简单,可以不分解;分析速度远快于其他分析方法,结果准确,单次测量一个样品只需要5 min,适用范围广,满足了科研和工业生产的需要。