高效液相色谱法测定车内非金属材料中甲醛含量的不确定度评估

依据测量不确定度评定与表示的方法,建立了高效液相色谱法测定车内非金属材料中甲醛含量的测量不确定度评定的数学模型,并对测试过程中各个不确定度分量的来源进行了分析和合成.结果表明,标准曲线的拟合和试验重复性对结果有较大影响.通过规范标准溶液配制的操作,降低测量结果的不确定度,有利于提高检测的准确性和一致性.     

An extensive study of transformation of the diatomics Hamiltonian operator from laboratory‐ to body‐fixed frame

Transformation of the diatomics Hamiltonian operator from the laboratory‐ to body‐fixed frame has been performed in great mathematical details by two methods: the method in which the transformation is performed directly using the chain rule of differentiation and the method in which the generalized form of multidimensional Laplacian operator is used as the starting point. To investigate the influence of the electronic spins on the motion of the molecule, the electronic spin variables are defined in the two frames and included in the transformations. © 2015 Wiley Periodicals, Inc.     

超声造影联合增强CT诊断不典型肝血管平滑肌脂肪瘤的临床价值

选取2011年6月~2017年6月于我院就诊的经病理学检查明确确诊为肝血管平滑肌脂肪瘤(HAML)的43例患者,通过对纳入患者的49个HAML病灶的超声造影(CEUS)及增强CT(CECT)的影像学表现及术前诊断结果进行分析,探讨CEUS联合CECT在诊断不典型HAML中的临床价值。结果显示,HAML在女性中的发病率显著高于男性(P<0.001),且HAML多为单发病灶(P<0.001)。术前经CECT准确诊断HAML者有34.69%,经CEUS准确诊断HAML者有57.14%,二者联合准确诊断HAML者有77.55%,联合诊断的准确性显著高于单独应用CECT或CEUS(P<0.05)。HAML在CECT和CEUS上的表现具有一定的特征性,二者联合应用可以提高HAML诊断正确率。     

Joint‐aggregation intumescent flame‐retardant effect of ammonium polyphosphate and charring agent in polypropylene

In order to explore the structure mode of intumescent flame retardants (IFRs) with higher efficiency, IFR particles with joint‐aggregation structure (@IFR) were obtained through the treatment of ammonium polyphosphate (APP) and a charring agent (PT‐Cluster) in their aqueous solution. Then, the joint‐aggregation IFR effect was researched using its application in polypropylene. In case of 20 wt% IFR loading, the limiting oxygen index (LOI) value of @IFR/PP was 1.1% higher than that of 15APP/5PT‐Cluster/PP mixture, and a 1.6 mm‐thick @IFR/PP composite passed the UL 94 V‐2 rating test, while 15APP/5PT‐Cluster/PP demonstrated no flame‐retardant rating in UL 94 vertical burning tests. In a cone calorimeter test, @IFR also had a better inhibition effect on heat release. The average heat release rate (av‐HRR) value during 0 to 120 seconds of @IFR/PP was only 41 kW m^?2, which was 33.9% lower than that of the 15APP/5PT‐Cluster/PP. Furthermore, the peak heat release rate (pk‐HRR) of @IFR/PP was 20.5% lower than that of 15APP/5PT‐Cluster/PP, and the time to pk‐HRR of @IFR/PP was 710 seconds, while that of 15APP/5PT‐Cluster/PP was 580 seconds. The better inhibition effect on HRR and the delay of time to pk‐HRR were caused by the joint‐aggregated structure of @IFR, which can rapidly react to form stable and efficient char layers. This kind of join‐aggregation IFR effect has great significance in suppressing the spread of fire in reality. In addition, @IFR also increased the mechanical properties of PP composites slightly compared with the APP/PT‐Cluster mixture.     

[WS3Cu2]簇基超分子框的组装、结构及其三阶非线性光学响应

将二(4-吡啶)硫烷(L₁)、4,4''-二(4-吡啶)二苯甲酮(L₂)分别与(Et₄N)(Tp*WS₃)(A)(Tp*=三(3,5-二甲基吡唑)氢合硼酸根)和[Cu (MeCN)₄]PF₆进行反应,得到2个W/Cu/S簇基超分子化合物[Tp*WS₃Cu₂(L₁)]₂(PF6)2·2MeCN·2CHCl₃(1·2MeCN·2CHCl₃)和[Tp*WS₃Cu₂(L₂)(MeCN)]₂(PF₆)₂·4MeCN (2·4MeCN)。对配合物1·2MeCN·2CHCl₃和2·4MeCN分别进行了单晶X射线衍射、核磁、质谱、红外、紫外可见和元素分析表征。单晶X射线衍射分析表明,它们是由2个L₁/L₂配体连接2个[Tp*WS₃Cu₂]⁺簇核形成的阳离子型簇基超分子框。核磁氢谱和高分辨电喷雾离子化质谱(HRESI-MS)证明它们在溶液中具有一定的稳定性。并利用Z扫描技术测试了超分子化合物1·2MeCN·2CHCl₃和2·4MeCN溶液的三阶非线性光学特性,测试结果表明它们的三阶非线性光学响应强于前驱体A。     

高频超声分析肩袖病变与肱二头肌长头肌腱病变临床特点及相关性

本文通过高频超声检查分析了肩袖病变与肱二头肌长头肌腱(long head of the biceps brachii tendon,LHBT)病变的临床特点及相关性.文中对32例肩关节镜手术患者的术前肩关节超声检查结果与肩关节镜手术结果进行了 一致性检验.按照不同肩袖病变类型对患者进行分组,对组间LHBT病变类型的差异...     

Shannon multiresolution analysis on the Heisenberg group

We present a notion of frame multiresolution analysis on the Heisenberg group, abbreviated by FMRA, and study its properties. Using the irreducible representations of this group, we shall define a sinc-type function which is our starting point for obtaining the scaling function. Further, we shall give a concrete example of a wavelet FMRA on the Heisenberg group which is analogous to the Shannon MRA on R.     

Mean size formula of wavelet subdivision tree on Heisenberg group

The purpose of this paper is to investigate the mean size formula of wavelet packets （wavelet subdivision tree） on Heisenberg group. The formula is given in terms of the p-norm joint spectral radius. The vector refinement equations on Heisenberg group and the subdivision tree on the Heisenberg group are discussed. The mean size formula of wavelet packets can be used to describe the asymptotic behavior of norm of the subdivision tree.