食品中辣椒红色素含量测量不确定度的评定

本文对高效液相色谱法测定食品中辣椒红色素含量的测定不确定度进行了评定,按照JJF1059-1999方法建立了数学模型,通过实验过程中取样器具、对照品的纯度,标准曲线拟合等不确定因素的分析,确定不确定度分量,合成不确定度.本评定方法客观、准确,在实际工作中有较强的实用性.     

Line and point cluster models for spatial health data

Spatial cluster modelling of small area disease incidence and mortality has previously focused on clusters where excess risk is distributed around fixed points, and the aim is the reconstruction of these points (cluster centers). Often there is a need to assess clusters of a different form, such as around roads or river systems. These clusters are often linear or can be approximated by combinations of several linear segments. In this paper the recovery of point and line clusters is considered jointly. An example application is given where both linear or point clustering could be present.     

Implementing automated diagnostic systems for breast cancer detection

This paper intends to an integrated view of implementing automated diagnostic systems for breast cancer detection. The major objective of the paper is to be a guide for the readers, who want to develop an automated decision support system for detection of breast cancer. Because of the importance of making the right decision, better classification procedures for breast cancer have been searched. The classification accuracies of different classifiers, namely multilayer perceptron neural network (MLPNN), combined neural network (CNN), probabilistic neural network (PNN), recurrent neural network (RNN) and support vector machine (SVM), which were trained on the attributes of each record in the Wisconsin breast cancer database, were compared. The purpose was to determine an optimum classification scheme with high diagnostic accuracy for this problem. This research demonstrated that the SVM achieved diagnostic accuracies which were higher than that of the other automated diagnostic systems.     

石化废水深度处理工艺技术优化研究

我国水资源的匮乏已经十分严重,如何实现节水减排,已成为一个十分紧迫的问题。但由于各行业生产性质不同,排放污水成分比较复杂,本文通过对某石化公司化工废水深度处理工艺运行中存在的问题进行改良优化研究,解决了影响系统运行平稳的问题,保证了该系统产水水质。     

Effect of interfacial interaction between graphene oxide derivatives and poly(vinyl chloride) upon the mechanical properties of their nanocomposites

In this work, graphene oxide (GO) and poly(methyl methacrylate) (PMMA) grafted GO reduced by dopamine (rGO@PDA-g-PMMA) were employed to determine the key factor responsible for the improved mechanical properties of poly(vinyl chloride) (PVC). Dopamine was utilized to reduce GO and simultaneous coating of polydopamine (PDA) on the GO surface. rGO@PDA-g-PMMA was prepared by a combination of mussel-inspired chemistry and surface-initiated atom transfer radical polymerization techniques. The resulting derivatives were characterized by thermogravimetric analysis, Fourier transforms infrared spectroscopy, X-ray diffraction, and Raman spectroscopy. PVC nanocomposites containing GO derivatives were prepared by solution blend and the nanocomposite films were obtained using a casting method. The mechanical properties of the nanocomposites were studied using both dynamic mechanical thermal analysis and tensile testing. The results revealed that the vital components responsible for the improved mechanical properties and thermal stability of rGO@PDA-g-PMMA/PVC nanocomposites compared to pure PVC are the interfacial interactions between the GO derivatives and the PVC matrix.     

High-pressure structural and electronic behaviors of superhard BC5: Density functional calculations

The structural and electronic properties of the recently synthesized superhard BC₅ are studied by using density functional theory within the generalized gradient approximation (GGA). P3m1-II structure is confirmed as the most stable state of BC₅ by comparing three potential structures. The high-pressure effect on superhard BC₅ is also successfully calculated. The obtained pressure dependence of structural property shows that the compressibility along three cell vectors is very close to each other. Based on the density of states (DOS), we find high pressure hardly change the DOS at Fermi level (E_F) which is related closely to the transition temperature T_c. The result is useful to further study the superconductivity of BC₅.     

Effects of sputtering parameters on the performance of electrodes fabricated for proton exchange membrane fuel cells

One way to alleviate the emission of air pollutants and CO₂ due to burning fossil fuels is the use of fuel cells. Sputter deposition techniques are good candidates for the fabrication of electrodes used for proton exchange membrane fuel cells (PEMFCs). Input power and sputtering-gas pressure are two important parameters in a sputtering process. However, little is known about the effects of these sputtering parameters on the performance of PEMFC electrodes. Therefore, this study applied a radio frequency (RF) magnetron sputter deposition process to prepare PEMFC electrodes and investigated the effects of RF power and sputtering-gas pressure in electrode fabrication on electrode/cell performance. At a Pt loading of 0.1 mg cm⁻², the electrode fabricated at 100 W, 10⁻³ Torr was found to exhibit the best performance mainly due to its lowest kinetic (activation) resistance (dominating the cell performance) in comparison to those fabricated by 50 and 150 W at 10⁻³ Torr, as well as by 10⁻⁴ and 10⁻² Torr at 100 W. In the tested ranges, the control of sputtering-gas pressure seems to be more critical than that of RF power for the activation loss. In addition to electrochemically active surface area, electrode microstructure should also be responsible for electrode/cell polarization, particularly the activation polarization.     

Highly selective electrocatalytic hydrogenation of cinnamaldehyde over tin dioxide-supported palladium nanocatalysts

Selective hydrogenation of α, β-unsaturated aldehydes has always been a hot research topic owing to favorable thermodynamics in CC hydrogenation. In this work, a series of Pd/SnO₂ nanocatalysts were facilely synthesized under mild conditions, via the reduction of Na₂PdCl₄ by dimethylaminoborane. Under galvanostatic electrolysis at 3.33 mA cm^?2 for 8 h, the selective conversion of cinnamaldehyde (CAL) was achieved over Pd/SnO₂-coated carbon fiber in neutral phosphate buffer, giving the cinnamyl alcohol (COL) selectivity of 78.85% at the conversion of 84.88%. The Pd/SnO₂ nanocatalysts outperform commercial Pd/C catalysts, showing high COL selectivity and faradaic efficiency. The cathodic reduction potential of CAL over Pd_4·3/SnO₂ occurs at ?0.92 V. The SnO₂ support is beneficial to promote the CO adsorption of CAL and lower the HER activity of Pd nanocatalysts, thereby contributing to superior activity of Pd_4·3/SnO₂ for selective hydrogenation of CAL.     

天然沥青对基质沥青低温改性研究

为了提高基质沥青的低温性能,采用新疆地产的天然沥青来改性基质沥青,以克拉玛依90#和110#2种基质沥青为例,通过在5℃和10℃的测力延度实验,计算了2种基质沥青在改性前后应力、断裂做功、温度敏感系数的变化,并通过改性前后玻璃化温度的变化来证实低温改性效果.实验结果表明,天然沥青对克拉玛依110#基质沥青的最佳掺比为5%,天然沥青对克拉玛依90#基质沥青的最佳掺比为7%,改性沥青表现出较好的低温性能.     

MSCT血管成像技术在门静脉高压症中的临床应用价值

目的探讨多层螺旋CT（MSCT）血管成像技术（MSCT angiography,MSCTA）在门静脉高压症（portal hy-pertension,PHT）诊断及临床治疗中的价值。方法对50例PHT患者者行MSCTA,观察患者门静脉系统的解剖学类型、门静脉主干及其分支侧支循环显示情况;观察食管胃底静脉曲张的形态、位置及血供类型。结果 50例门静脉高压症患者门静脉及侧支循环显影包括：食管下段静脉曲张94.0%,胃底静脉曲张90.0%,胃左静脉曲张90.0%,食管旁静脉曲张72.0%,胃短、胃后静脉曲张32.0%,脾/胃-肾静脉分流28.0%,副脐静脉、腹壁静脉曲张26.0%,腹膜后-椎旁静脉曲张22.0%。对21例患者施行手术,手术与影像学诊断完全符合。MSCTA检出胃静脉曲张（gastric varices,GV）阳性49例所见的病状与胃镜下所见病状对比一致性较好。结论 MSCTA能为PHT患者判断病变程度、预测其并发症及选择治疗方案提供可靠的依据。