Epifluorescence microscopy study of a quadruple node of triple junctions of grain boundaries in a Eu2+‐doped Kcl:Kbr solid solution by using the doping ion as a fluorochrome

A typical quadruple node (QN) of triple junctions (TJs) of grain boundaries (GBs) in a Eu²⁺‐doped KCl_0.52Br_0.48 solid solution is investigated from the geometrical point of view by epifluorescence microscopy using the doping ion as a fluorochrome. The excitation and fluorescence optical properties of the fluorochrome were previously characterised by spectrophotometry whereas the structural nature of the studied material as well as its Bravais lattice type, unit cell size and long‐range translational order degree was determined by X‐ray diffraction. A three‐dimensional reconstruction was built from the microscopy images of different optical cross‐sections of the studied arrangement of crystal defects. In the close vicinity of the QN, the studied arrangement of crystal defects adopts the geometry of a collapsed tristetrahedron which, centred at the QN, has its legs along the TJs and, hence, has its faces as collapsed in pairs into the GBs. The angles defined by different TJ couples as well as the dihedral angles defined by the different GB couples meeting in every TJ were measured at the QN site. All, the image recording and stacking as well as the measuring procedures are carefully described. The measured TJ angles (97°, 117°, 95°, 117°, 99° and 130° ± 2°) depart from the characteristic angle (109.47°) of a tetrahedron whereas the measured GB angles (101°, 119°, 140°; 125°, 127°, 108°; 133°, 109°, 119°; 129°, 99° and 132° ± 2°) depart from the angular argument (120°) of a 3‐fold symmetry rotation indicating that, in the close neighbourhood of the QN, the studied arrangement of crystal defects is structurally unstable. Such an instability is associated with an observed mismatch in orientation (by angles of 20°, 15°, 33° and 30° ± 2°) between the TJs and some <111> zone axis matrix lattice crystallographic directions ([], [11], [11] and [11]), respectively). Local variations in anionic composition, existing within the solid solution matrix, are discussed to be responsible for this mismatching and, therefore, for the observed structural instability.     

Pd/C纳米结构的尺寸调控及液相高效加氢脱氯性能

在甲酰胺体系下,利用KBr调控合成了Pd粒径为2 nm、3 nm、4 nm和6 nm的不同水溶性Pd/C催化剂,采用TEM、XRD和XPS对催化剂进行表征,并以4-氯苯酚为反应物,测试了催化剂的液相加氢脱氯性能。结果表明,相比于商业Pd/C催化剂,在甲酰胺体系中合成的Pd/C催化剂具有更高的水溶性,催化效果提高了约40%以上。同时研究了不同溶剂对催化剂加氢脱氯效果的影响,结果表明,随着溶液极性、溶剂的介电常数(ε)、偶极矩(μ)和归一化极性参数(ETN)的增强,催化效果越好。     

The reliability of traditional authentication – A case of ginseng misfit

Ginseng is a famous herb in traditional Chinese medicine. Herbs like ginseng have traditionally been authenticated by morphological and histological means, but it is difficult to identify these herbs nowadays since they look morphologically similar. The quality of food and pharmaceutical products is important for ensuring efficacy and consumer safety. Although several studies have stated that these traditional methods of authenticating ginseng are now hardly reliable, there have been little or no studies which have documented the reliability of such approaches. We report in this study a case of misidentification of ginsengs based on traditional methods of authentication via morphology, and the ability of using infrared spectroscopy and principal component analysis as a rapid form of quality surveillance by discriminating this error.     

Surface characterization method of oxygen plasma-treated UHMPE fiber using DRIFT spectroscopy

The surface treatment and characterization of ultrahigh modulus polyethylene (UHMPE) fiber has been an important research subject. In this study, in order to investigate the oxygen plasma-treated UHMPE fiber according to the treatment time, diffuse reflectance Fourier transform infrared (DRIFT) spectroscopy was used as an analysis tool. The UHMPE fiber in a plain fabric was used for the surface analysis. The KBr overlay technique was efficient for enhancing the characteristic peaks from the UHMPE fiber surface. However, the KBr overlay made the comparison of the spectra among the UHMPE fiber samples difficult due to the different KBr overlay amount of each sample. In order to compare the relative peak areas of the oxygen plasma-treated UHMPE fiber according to the treatment time, DRIFT analysis was performed without KBr overlay under constant fiber orientation to remove the fiber orientation effect. The spectral subtraction was useful for investigating the minute change of the UHMPE fiber after the oxygen plasma treatment under the constant fiber orientation. The peak at 1896 cm⁻¹ was assigned to the crystalline combination mode of the UHMPE fiber and remained almost the same after the oxygen plasma treatment. This peak was used as an internal standard peak for the spectral subtraction and the peak area normalization. The relative peak areas in the DRIFT spectra of the UHMPE fiber were compared according to the oxygen plasma treatment time. The C=O group increases and the C—O group decreases as the oxygen plasma treatment time increases. The DRIFT analysis data of the oxygen plasma-treated UHMPE fiber correlated well with the electron spectroscopy for chemical analysis data and DRIFT spectroscopy is known to be useful for investigating the UHMPE fiber surface. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1117–1124, 1998     

Optical absorption of Tl+ ions in KBr1-xIx:TlI mixed crystals

spectra of gamma irradiated mixed crystals showed F band, which shifts towards low energy side with the composition of iodine ions in the mixed crystals.     

利用多种分析手段鉴定三个未知物样品

研究了如何利用多种先进的仪器设备，综合分析研制未知样品及其含量的测定。     

Determination and Correlation of Liquid–Solid Phase Behaviors of Polyhydric Alcohol + KBr + H2O Ternary Systems at 288.15, 298.15, and 308.15 K

The solubility, density, and refractive index of 1,2-propanediol + KBr + H₂O, ethylene glycol + KBr + H₂O, and glycerin + KBr + H₂O ternary systems are determined at 288.15, 298.15, and 308.15 K. In all cases, the solubility of KBr decreases with increasing concentration of polyhydric alcohol. The liquid–solid equilibrium experimental data are correlated using the nonrandom two-liquid (NRTL) activity coefficient model, considering nondissociation of the dissolved salt in the liquid phase, and new interaction parameters are estimated. The mean deviations show a good applicability of the NRTL model. Simultaneously, the corresponding unsaturated systems are investigated, and the concentration factors are discussed.     

A Modeling Investigation of Suppressant Distribution from a Prototype Solid-Propellant Gas-Generator Suppression System into a Simulated Aircraft Cargo Bay

One new technology for fire suppressant distribution in total-flooding applications is the solid-propellant gas-generator (SPGG) technology. This article presents experimental and modeling studies of one such prototype system in order to better understand observations in the testing of this system. This particular SPGG system generates fine particles that act to suppress any fire in conjunction with inert gases also generated in the SPGG system. Initial conditions for the simulations are obtained from the available measurements of the prototype system. The modeling provides key information related to the distribution of the particles and their potential effectiveness as a fire suppressant. The primary variable in the SPGG design as identified in the initial measurements, also presented here, was the particle size, with typical particle sizes being measured at 2 and 15 µm. The key modeling result is that there is a tradeoff between the most uniform distribution of particles and the available surface-to-volume ratio for chemical suppression. Information is also provided regarding the thermal dissipation from the SPGG system.     

Pitzer混合参数对KBr-CsBr-H2O体系25℃时溶解度预测的影响

利用Pitzer混合参数,计算了KBr-CsBr-H2O体系25℃时的溶解度以及两离子作用参数(θKCs)和三离子作用参数(ψKCsBr)各以±10%变动时,KBr-CsBr-H2O三元体系25℃溶解度的变化。计算结果表明,θKCs和ψKCsBr对溴化钾、溴化铯的溶解度有影响。当θKCs增加同时ψKCsBr减小或者θKCs减小同时ψKCsBr增加时,溶解度的变化最小;而θKCs和ψKCsBr同时增加或减小时,溶解度的变化最大。从定量的角度说明了θKCs和ψKCsBr对体系性质的影响和电解质溶液的相互作用。