固态阴极射线器件复合加速层的研究

固态阴极射线器件的加速层,是提高固态阴极射线性能的重要部分,它能够加大电子能量,倍增电子数量。其中增加注入电子从而提高过热电子的数量,是提高固态阴极射线器件性能的关键。为此 ,文章尝试将加速层复合,兼顾加速与电子注入性能。首先将SiO₂,ZnS和ZnO分别与有机聚合物MEH-PPV组合,确定较适合的复合加速层的组合：SiO₂/ZnS和 ZnO/SiO₂。然后将这两种复合加速层的性能对比,发现SiO₂/ZnS的性能更优越,因为电子注入性能ZnS和ZnO相当,而电子加速倍增性能ZnS明显优于ZnO,其中 SiO₂为主要的加速层,而ZnS起到降低注入势垒变成阶梯势垒的作用。最后又将复合加速层结构的固态阴极射线器件和传统的SiO₂夹层固态阴极射线器件对比,发现这种复合 加速层结构,尤其在高场下,可提高固态阴极射线的初电子源和过热电子的数目,从而提高其发光效率具有促进作用。     

Determination of trace triclosan in environmental water by microporous bamboo‐activated charcoal solid‐phase extraction combined with HPLC‐ESI‐MS

A sensitive and efficient analytical method for triclosan (TCS) determination in water, which involves enrichment with bamboo‐activated charcoal and detection with HPLC‐ESI‐MS, was developed. The influence of several operational parameters, including the eluant and its volume, the flow rate, the volume andacidity of the sample, and the amount of bamboo‐activated charcoal, were investigated and optimized. Under the optimum conditions, linearity of the method was observed in the range of 0.02–20 μg/L, with correlation coefficients (r²) >0.9990. The limit of detection was 0.002 μg/L based on the ratio of chromatographic signal to baseline noise (S/N = 3). The spiked recoveries of TCS in real water samples were achieved in the range of 97.6–112.5%. The proposed method was applied to analyze TCS in real aqueous samples. All the surface water samples collected in Xiaoqing River had detectable levels of TCS with concentrations of 42–197 ng/L.     

The New Homoleptic Tetracyanamidoaluminate LiBa2[Al(CN2)4]

The new tetracyanamidoaluminate LiBa₂[Al(CN₂)₄] was prepared by solid state metathesis reaction in a fused copper ampoule from a mixture of BaF₂, AlF₃, and Li₂(CN₂) at 550 °C. The crystal structure was solved and refined based on single‐crystal X‐ray diffraction data [P2₁2₁2₁, Z = 4, a = 6.843(1) Å, b = 11.828(2) Å, c = 11.857(2) Å]. The compound belongs to the known formula type LiM₂[Al(CN₂)₄] (M = Sr, Eu) containing the homoleptic [Al(CN₂)₄]^5– ion. However, LiBa₂[Al(CN₂)₄] forms a distinct crystal structure, containing a two‐dimensional [(NCN)_2/2Li(NCN)₂Al(NCN)_2/2] network with four‐coordinate Li⁺ and Al³⁺ ions. Two crystallographically independent Ba²⁺ ions are situated in eightfold environment of terminal nitrogen atoms of cyanamide ions.     

Solid-Phase Stereoselective Synthesis of (E)-1, 2-Disubstituted Ethenes from Polymer-Sopported a-Selenoaldehydes

Reaction of polymer-supported a-selenoaldehydes with Grignard reagents afforded polymer-bound B-hydroxyalkyl selenides, which treated with thionyl chloride and triethylamine leading to (E)-1, 2-disubstituted ethenes in good yield.     

共压共烧结法制备固体氧化物燃料电池及其结构性能分析

用共压 共烧结法制备以Ce0.8Gd0.2O1.9(CGO)作电解质的中温固体氧化物燃料电池,其中CGO和阴极材料La0.6Sr0.4Co0.2Fe0.8O3-α(LSCF)由溶胶凝胶法合成.实验表明,,由共压 共烧结法制备的上述材料组装的电池具有致密的电解质层,且与电极的结合非常紧密,测得的最大输出功率0.14W/cm2,相应的操作温度为650℃,电流密度为307mA/cm2.该电池的电化学过程为内阻和浓差极化联合控制,使用造孔剂可改善阳极基底的孔隙结构,降低浓差极化过电位.     

固相萃取高效液相色谱法分析酱油中的有机酸

用ＰＴ－Ｃ１８预１８预处理小柱进行样品的前处理,以μＢｏｎｄａｐａｋ Ｃ１８为分析,磷酸盐缓冲液作流动相,紫外２１４ｎｍ检测,建立了酱油中多种有机酸的高效液相色谱分析方法,回收率９６％－１１３％。     

固体核磁共振研究碱土金属磷硅酸盐玻璃的六配位硅结构

Phosphate glass is widely used in optical applications; however, its generally low chemical stability and poor thermal mechanical properties hinder the application of phosphate glass to the rapidly evolving laser industry. The addition of a small amount of silicon can form a six-coordinate Si (Si⁽⁶⁾) network and improve the above-mentioned poor properties of phosphate glass. Therefore, it is important to characterize and understand the structural details of phosphosilicate glasses. It is difficult to investigate the glass structure because of its complicated and disordered characteristics. However, solid-state nuclear magnetic resonance (NMR) spectroscopy can provide detailed local structural information, regardless of the presence of its long-range order. To study the effect of alkaline earth metals on Si⁽⁶⁾ species formation, we prepared phosphosilicate glasses (2MO-3P₂O₅)_(1−x)·(SiO₂)_x (M = Ca, Sr, Ba) by conventional melt-quenching, and the glass structure was investigated by solid-state NMR and Raman spectroscopy. The ³¹P and ²⁹Si NMR spectra indicated that the glass networks consisted of P⁽²⁾ and P⁽³⁾ tetrahedrons linked via four- and six-fold coordinated silicon units (Si⁽⁴⁾ and Si⁽⁶⁾). The fraction of six-coordinated silicon Si⁽⁶⁾ decreased with increasing SiO₂ content. Similarly, the Raman spectra showed that the vibration band of the P＝O stretching mode in P⁽³⁾ linked with Si⁽⁶⁾ neighbors reduced as the silica content increased. The connectivities between various phosphorus species were probed by ³¹P one- and two-dimensional refocused INADEQUATE experiments. This experimental technique is based on homonuclear J-coupling and yields correlation peaks between nuclei engaged in P―O―P linkages (P⁽²⁾ and P⁽³⁾ units). The signals from isolated ³¹P nuclei are suppressed because of the absence of J-coupling, which precludes the formation of double quantum coherences. The results indicated the segregation of P⁽²⁾ and P⁽³⁾ units in the prepared glass, which were also compared with those in the previously reported Na₂O-P₂O₅-SiO₂ glasses. They differed from alkali phosphosilicate glasses, where each P⁽³⁾ unit exhibited a maximum average of one Si⁽⁶⁾―O―P⁽³⁾ linkage, and in the alkaline earth phosphosilicate glasses, the average was approximately 0.4–0.7. When the content of Si⁽⁶⁾ units reached its maximum, further increase in the SiO₂ content did not increase the Si⁽⁶⁾ content, and the surplus Si were present as Si⁽⁴⁾. Alkaline earth metal ions exhibit weaker stabilizing effects for Si⁽⁶⁾ species. Based on the results presented herein, we constructed sketches to illustrate the local structural organization of the glass. The relationships between the compositions and structures are important for glass composition and property design. It is important to improve the performance of phosphate glass by changing its composition, particularly for large laser device applications.     

Molecular miscible blend of poly(2-cyano-1,4-phenyleneterephthalamide) and polyvinylpyrrolidone characterized by two-dimensional correlation FTIR and solid state C NMR spectroscopy

Miscibility of blends of poly(2-cyano-1,4-phenyleneterephthalamide/polyvinylpyrrolidone) (CN-PPTA/PVP) was investigated by dilute solution viscometry, two-dimensional (2D) correlation Fourier transformed infrared (FTIR) spectroscopy and solid state ¹³C NMR spectroscopy. It was shown that a large proportion of the PVP, the water-soluble component, could not be removed from CN-PPTA by extraction with water, and even with boiling water for blend films, suggesting that the flexible aliphatic PVP chain forms a blend with the rigid aromatic CN-PPTA chain through strong intermolecular interaction making it too difficult to dissolve even in boiling water. Viscometry on a polymer mixture of dilute solution showed that [η]_exp exhibited larger value than [η]_theo in all mixtures used in this experiment, suggesting occurrence of a strong attractive interaction between the two polymers. 2D correlation FTIR spectroscopy revealed that the carbonyl absorption band of PVP at 1675 cm⁻¹ shifted to a new low frequency absorption band at 1640 cm⁻¹ with a change of 35 cm⁻¹, suggesting strong hydrogen bonding with NH (amide II) proton of CN-PPTA. Another new absorption band at 1685 cm⁻¹ was due to the carbonyl absorption band of CN-PPTA shifting to a higher frequency than that at 1662 cm⁻¹, indicating that some of the carbonyl groups in the CN-PPTA components of the blends were in a free state or in a non-hydrogen bonded state as a consequence of the participation of NH proton of CN-PPTA in hydrogen bonding, resulting in the absorption bands of NH bend deformation of CN-PPTA at 1542 and 1313 cm⁻¹ being shifted to higher wavenumber of 1556 and 1324 cm⁻¹, respectively. Solid state ¹³C NMR spectroscopy revealed a chemical shift for CO of the PVP component in the blend fiber changing down-field (shift to left) at 177.346 ppm with a difference of 1.812 ppm; this was due to a lower electron density around the carbon atom of CO of lactam via hydrogen bonding with NH proton of amide in the CN-PPTA component, suggesting that a homogeneous blend of the CN-PPTA and PVP was produced on a molecular scale via hydrogen bonding.     

生物基质中全氟辛酸与全氟辛烷磺酸及其前体化合物的超高效液相色谱-串联质谱法研究

建立了超高效液相色谱-串联三重四级杆质谱(UPLC-MS/MS)测定血清基质与肝匀浆基质中全氟辛酸与全氟辛烷磺酸及其前体化合物的方法.相对应的生物基质中的目标化合物分别用水或甲醇超声提取后,过固相萃取柱(Waters Oasis(R) WAX 3cc)进行净化,并分别使用甲醇洗脱前体化合物,90%氨水-甲醇洗脱全氟辛酸...     

Influence of phosphorus valency on thermal behaviour of flame retarded polyurethane foams

This paper reports decomposition/pyrolysis studies of polyurethane (PU) rigid foams containing phosphinate, phosphonate or phosphate as flame retardant in order to study the effect of phosphorus oxidation state on their gas and/or solid phase action. The flame retardants analyzed were aluminium phosphinate (IPA), dimethylpropanphosphonate (DMPP), triethylphosphate (TEP) and ammonium polyphosphate (APP), which differ in oxidation state and/or decomposition temperature. Gases evolved during TGA analyses as well as solid residues have been studied by means of MS and FTIR.The results show that phosphorus flame retardants which significantly lose weight at temperatures lower than those of neat PU foams act in the gas phase irrespective of their valency: indeed, they are completely volatilized before polymer decomposition starts and thus no interaction between flame retardant and polymer can be expected. The effect of phosphorus oxidation state becomes important when flame retardant decomposition takes place in the same temperatures range as neat polymer. In this case, it seems that at lower P oxidation state (+1) a combined gas and solid phase action takes place while at higher P oxidation state (+5) only solid phase action was observed.