1,9-双(1'-苯基-3'-甲基-5'-氧代吡唑-4'-基)壬二酮-[1,9]与三辛基氧膦对镧(Ⅲ)、镝(Ⅲ)的协同萃取

研究了１，９－双（１－苯基－３－甲基－５－氧代吡唑－４－基）壬二酮－［１，９］（ＢＰＭＰＮＤ，Ｈ２Ａ）与三辛基氧膦（ＴＯＰＯ，Ｂ）的氯仿溶液，从硝酸介质中对Ｌａ（Ⅲ）、Ｄｙ（Ⅲ）的协同萃取，计算了体系的酸性协萃系数ＲＡ和协萃系数Ｒ，用斜率法测得协萃合物的组成为ＬａＡ·ＨＡ·Ｂ和ＤｙＡ·ＨＡ·Ｂ，计算了协萃平衡常数，研究了温度对协萃反应的影响，用萃取法制得了固态协萃合物，并对其组成、ＩＲ及ＴＧ－ＤＴＡ进行了研究．     

液氢加注系统低温管道中的两相流仿真与分析

在液氢加注输送过程中,由于其具有低温和高压的特性,极易产生气液两相流,而使管道发生过压故障.因此,对液氢管道的仿真研究有着重要作用.文中对裸态和防护后的液氢管道进行建模计算,并通过AMESim软件的两相流库对氢物理属性和管道模型进行仿真分析,然后对系统的对液氢输送管道进行了应用改进与分析.仿真结果表明:液氢在裸管道中输...     

Near‐infrared surface‐enhanced Raman spectroscopy (NIR‐SERS) studies on oxyheamoglobin (OxyHb) of liver cancer based on PVA‐Ag nanofilm

A near‐infrared surface‐enhanced Raman spectroscopy (NIR‐SERS) method was employed for oxyheamoglobin (OxyHb) detection to develop a simple blood test for liver cancer detection. Polyvinyl alcohol protected silver nanofilm (PVA‐Ag nanofilm) used as the NIR‐SERS active substrate to enhance the Raman scattering signals of OxyHb. High quality NIR‐SERS spectrum from OxyHb adsorbed on PVA‐Ag nanofilm can be obtained within 16 s using a portable Raman spectrometer. NIR‐SERS measurements were performed on OxyHb samples of healthy volunteers (control subjects, n = 30), patients (n = 40) with confirmed liver cancer (stage I, II and III) and the liver cancer patients after surgery (n = 30). Meanwhile, the tentative assignments of the Raman bands in the measured NIR‐SERS spectra were performed, and the results suggested cancer specific changes on molecule level, including a decrease in the relative concentrations and the percentage of aromatic amino acids of OxyHb, changes of the vibration modes of the C_aH_m group and pyrrole ring of OxyHb of liver cancer patients. In this paper, principal component analysis (PCA) combined with independent sample T test analysis of the measured NIR‐SERS spectra separated the spectral features of the two groups into two distinct clusters with the sensitivity of 95.0% and the specificity of 85.7%. Meanwhile, the recovery situations of the liver cancer patients after surgery were also assessed using the method of discriminant analysis‐predicting group membership based on PCA. The results show that 26.7% surgeried liver cancer patients were distinguished as the normal subjects and 63.3% were distinguished into the cancer. Our study demonstrated great potentials for developing NIR‐SERS OxyHb analysis into a novel clinical tool for non‐invasive detection of liver cancers. Copyright © 2013 John Wiley & Sons, Ltd.     

A Note on Semi-coloring of Graphs

Semi-coloring is a new type of edge coloring of graphs. In this note, we show that every graph has a semi-coloring. This answers a problem, posed by Daniely and Linial, in affirmative. It implies that every r-regular graph has at least ${\lceil\frac{r}{2}\rceil}$ different {K ₂, C _i | i ≥ 3}-factors.     

Sulfur-doped black silicon formed by metal-assist chemical etching and ion implanting

We fabricated sulfur-doped black silicon by metal-assist chemical etching (MCE) and ion implanting. The morphologies of silicon nanowire (SiNW) arrays and the concentration of sulfur in black silicon were analyzed by scanning electron microscope (SEM). Sulfur-doped black silicon shows higher absorption in entire 0.3–2.5 μm wavelength range as compared to undoped SiNW arrays and flat silicon. The changes in the absorption spectra of black silicon with different etching durations and annealing temperature are also shown. Upon annealing, the absorption decreases significantly in 2–2.5 μm wavelength region. The novel results clearly indicate that sulfur implanting could produce below band gap absorption in the silicon substrate.     

The flow of a micropolar fluid through a porous channel with expanding or contracting walls

The flow of a micropolar fluid in a porous channel with expanding or contracting walls is investigated. The governing equations are reduced to ordinary ones by using similar transformations. Homotopy analysis method (HAM) is employed to obtain the expressions for the velocity fields and microrotation fields. Graphs are sketched for the effects of some values of parameters, especially the expansion ratio, on the velocity and microrotation fields and associated dynamic characteristics are analyzed in detail.     

A dual functional 1D Cd-based coordination polymer for the highly luminescent sensitive detection of Fe3+ and picric acid

Fluorescent coordination polymers have drawn extensive attention in sensing applications. Herein, we report a carbazole-based one-dimensional coordination polymer [CdL(H₂O)(DMF)₂]·DMF ( CdL , H₂L = 9H-carbazole-2,7-dicarboxylic acid, DMF = N,N-dimethylformamide). In CdL , each Cd²⁺ ion is four-bridged by carboxylates, which is further linked by the carbazole units to form a one-dimensional Cd–O–C chains along the c-axis. CdL displays high water stability in the pH range of 3–10. Luminescence experiments indicate that CdL could selectively detect Fe³⁺ during the concentration range of 0–0.1 mm in water with a K_sv of 8022 m ⁻¹ and picric acid (PA) within the concentration range of 0–0.05 mm in methanol solution with a K_sv of 17948 m ⁻¹ respectively. The above results reveal that CdL can be applied as a multiresponse luminescence sensor for selectively sensing for Fe³⁺ in water and PA in methanol solution.     

Syntheses,structures, and properties of four coordination polymers based on 2,7-di(pyridin-4-yl)-9H-fluoren-9-one

Four coordination polymers (CPs), [Cd(2,7-dpfo)₂(NO₃)₂(CH₃OH)]_n (1) , [Zn(2,7-dpfo)(NO₃)(CH₃COO)]_n (2) , [Co(2,7-dpfo)₂(H₂L)]_n (3) , and [Ni(2,7-dpfo)₂(H₂L)]_n (4) (where 2,7-dpfo is 2,7-di(pyridin-4-yl)-9H-fluoren-9-one and H₄L is 1,1′:4′,1′′-terphenyl-4,2′,5′,4′′-tetracarboxylic acid), were synthesized and structurally characterized. Compounds 1 – 4 were determined by elemental analyses, single crystal X-ray diffraction analyses, powder X-ray diffraction, infrared spectroscopy, and thermogravimetric analyses. Compound 1 displays a one-dimensional (1D) zigzag chain structure, while compound 2 possesses a 1D ladder chain structure. Compounds 3 and 4 are isostructural and consist of 1D chains. The solid-state luminescent properties of 1 and 2 and the magnetic properties of 3 and 4 were also investigated.     

SMA/蒙脱石纳米复合材料增容PA6/ABS共混体系

采用原位插层法制备苯乙烯-马来酸酐交替共聚物/蒙脱石(SMA/MMT)纳米复合材料增容PA6/ABS共混体系,并与SMA及MMT的增容效果进行比较,运用TEM、SEM、DSC及XRD研究了增容剂SMA/MMT及MMT的增容机理.结果表明,采用SMA做增容剂,体系机械性能下降;MMT可使体系拉伸强度提高,但冲击强度下降;采用SMA/MMT纳米复合材料做为增容剂,可提高共混体系的强度及韧性.TEM、XRD、DSC及SEM研究结果表明,PA6/ABS/(SMA-MMT)体系中MMT主要分布于两相界面处,ABS及PA6分子链可进入MMT层间,形成类似于共聚物结构,起到增容剂的作用,从而降低分散相粒径,增加两相界面作用力,有利于体系力学性能的提高.PA6/ABS/MMT体系中MMT主要分布于连续相PA6中,虽然对分散相粒径影响较小,但增强了PA6相强度,使得体系力学性能提高.     

Synergistic Doping and Intercalation: Realizing Deep Phase Modulation on MoS2 Arrays for High‐Efficiency Hydrogen Evolution Reaction

A synergistic N doping plus PO₄^3? intercalation strategy is used to induce high conversion (ca. 41 %) of 2H‐MoS₂ into 1T‐MoS₂, which is much higher than single N doping (ca. 28 %) or single PO₄^3? intercalation (ca. 10 %). A scattering mechanism is proposed to illustrate the synergistic phase transformation from the 2H to the 1T phase, which was confirmed by synchrotron radiation and spherical aberration TEM. To further enhance reaction kinetics, the designed (N,PO₄^3?)‐MoS₂ nanosheets are combined with conductive vertical graphene (VG) skeleton forming binder‐free arrays for high‐efficiency hydrogen evolution reaction (HER). Owing to the decreased band gap, lower d‐band center, and smaller hydrogen adsorption/desorption energy, the designed (N,PO₄^3?)‐MoS₂/VG electrode shows excellent HER performance with a lower Tafel slope and overpotential than N‐MoS₂/VG, PO₄^3?‐MoS₂/VG counterparts, and other Mo‐base catalysts in the literature.