In-depth analysis of glass fibers

Two types of commercial glass fibers were subjected to attack in strongly basic KOH solutions. The resulting leach solutions were analysed for Na, Ca, and Si. This showed that the corrosion process attacks the fibers incongruently. Although there are some distinct differences in the performance of these fibers, to a first approximation both types behave similarly. Further, the fibers were depth profiled using a recently developed SNMS technique for fiber in-depth analysis. This showed that both types of fibers behave in a quite dissimilar manner. The fibers were weathered already without any treatment. Although both fibers show alkali ion exchange and network splitting processes, on one of the fiber layers enriched in SiO₂, Fe₂O₃, and CaO are formed by a redeposition process from the leach solution.Dedicated to Professor Dr. rer. nat. Dr. h.c. Hubertus Nickel on the occasion of his 65th birthday     

Radio-Frequency Hexamethyldisiloxane Plasma Deposition: A Comparison of Plasma- and Deposit-Chemistry

This study reports on the effect of input power to hexamethyldisiloxane (HMDSO) plasmas. The power dependence of the plasma-phase species and of the surface chemistry (of the deposits) has been investigated. Neutral and positive molecular species were detected within the plasma using mass spectrometry (MS). Secondary ion mass spectrometry (SIMS) was used to probe the molecular structure of the deposits. The elemental composition of the surface was determined by XPS and the deposition rate was monitored using a vibrating quartz crystal microbalance. Neutral and cationic molecules of mass greater than HMDSO were detected in the plasma. Their formation through ion-molecule reactions is proposed. Changes in the relative concentration of plasma-phase species follow those seen in molecular species detected at the deposit surface. Thus, we believe that the molecular structure of the deposits can be related to the species present in the plasma. While traditionally the dominant mechanism in deposit formation is assumed to be free radical combinations, we propose other possibilities involving cations with the aim of putting forward a new perspective on plasma polymerization mechanisms and thereby stimulating discussion.     

Thermodynamic investigation of the state of water adsorbed by carbonaceous adsorbents

The state of water adsorbed on active carbons and canal soot was studied using the “chemical potential—entropy—temperature” diagram. In the range of the relative pressures from 0.174 to 1, the state of adsorbed water is similar to the state of a stretched liquid. The molar volume, heat of evaporation, and surface tension of stretched water were calculated at different relative pressures. Near the spinodal, the molar volume of stretched water is 25% higher, and the surface tension is considerably lower compared to water. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 464–468, March, 1997.     

Study on the effects of fluorine and oxygen deficiency on YBa2Cu307 byab initio method

The calculations of clusters modeling the fluorine-doping and oxygen deficiency of YBa₂Cu₃0₇ have been performed by the method of all-electronab initio Hartree-Fock with self-consistent crystal field. Results show that in CuO planes electric charge significantly increases, the chemical valence of Cu decreases and the covalent bonding of Cu-O greatly weakens owing to oxygen deficiency, while the effect of F restores the local electronic structure of YBa₂Cu₃O₇. The reported opinion that F occupied the oxygen vacancy in Cu-O chains seems disputable according to the calculated bonding characteristics Project supported by the National Natural Science Foundation of China.     

基于聚合物添加剂谱库的缓冲盐中塑料药品包装材料难挥发可溶出物的快速分析方法研究

采用超高效液相色谱-四极杆飞行时间质谱(UPLC-QTOF-MS),结合基于UNIFI软件建立的174种聚合物添加剂的谱库,实现了塑料药品包装材料中难挥发可溶出物(Extractables)的快速筛查和准确定量。样品经氯仿萃取后,以甲醇和0.1%甲酸水溶液为流动相在CORTECS C18(2.1 mm×100 mm,1.6μm)色谱柱上进行分离,在质谱电喷雾正离子模式下,UPLC-QTOF-MS进行筛查和定量分析。结果表明,浸泡60 d缓冲盐(25℃)中检出4种物质,利用谱库筛查确定其中1种物质是邻苯二甲酸二异癸酯(DIDP),采用外标法定量,测得其溶出量为1.98μg/L;其余3种物质可通过精确质量数、MSE谱图等进行推断定性,利用结构与质量数相近的邻苯二甲酸二环己酯(DCHP)为内标进行定量,3种提取物的总含量为10.80μg/L。利用DIDP进行回收率实验,5,10,20μg/L 3个加标水平的回收率为90.1%~97.1%,相对标准偏差(RSD,n=6)不大于3.7%。该方法快速、准确、灵敏,适用于药品包装材料的安全性考察。     

液相色谱-串联质谱法快速筛查减肥类中药及保健品中非法添加30种化学药

建立了中药及保健品中30种减肥类化学药的高效液相色谱-串联质谱(LC-MS/MS)快速筛查方法。实验优化了前处理方法、色谱分离条件和质谱参数。样品采用甲醇超声萃取,Agilent poroshell 120 ECC18(4.6 mm×100 mm,2.7μm)色谱柱分离,流动相为乙腈-水溶液(含10 mmol/L甲酸铵,0.1%甲酸,10%甲醇),梯度洗脱,流速0.25 m L/min,采用正负离子切换模式的电喷雾质谱检测,多反应选择离子监测(MRM)。该方法能同时筛查30种化学药,覆盖面广,简便、快速、准确可靠,已用于减肥类中药及保健品中非法添加化学药的筛查及检测。     

组合肽配体库技术富集蛋白研究进展

低丰度蛋白是生物体中重要的活性物质,参与新陈代谢、转录和翻译等多种生理及病理过程,因此对低丰度蛋白的研究具有重要意义。组合肽配体库技术(CPLL)是富集低丰度蛋白的一种有效方法,通过CPLL富集作用可以实现低丰度蛋白的检测与鉴定。该文总结了CPLL应用于不同领域中(包括人体、动物源、植物源等蛋白研究方面)低丰度蛋白样品的富集研究,可为CPLL的进一步应用提供参考。     

Well Oriented ZnO Nanorods Array: Negative Resistance and Optical Switching

Well‐oriented ZnO nanorods (NRs) arrays were grown on Si, alumina, quartz, and FTO substrates through a ZnO seed layer followed by low temperature wet chemical process. The influence of sputtered ZnO seed layer thickness (100, 50, 32, and 16 nm), annealing temperature and CuO_x coverage on the characteristics of ZnO NRs were investigated in this study. The crystalline structural, chemical, morphological, optical, and electrical properties of ZnO NRs arrays were studied by X‐ray diffraction (XRD), field emission‐ scanning electron microscopy equipped by energy dispersive X‐ray spectroscopy (FE‐SEM/EDX), Raman scattering, UV/Vis ‐ near IR absorption spectroscopy and current‐voltage characteristic. XRD and Raman spectra measurement revealed that the synthesize ZnO displayed hexagonal wurtzite structure. The individual rod diameter, density, and orientation can be controlled by varying the seed layer thickness. The mean diameter and maximum length of ZnO NRs are around 55–66 nm and 282 nm, respectively. ZnO NRs/ ZnO thin film structure shows optical switching and negative differential resistance behavior as applicable to ON/OFF gate and memory devices.     

A C2 Fragment as Four‐Electron σ Donor

The formation and X‐ray structure analysis of the Pt^IV complex [(CH₂C{PPh₂C₆H₄}₂)PtI₂] is reported. The molecule possesses the orthometalated ligand (PPh₃)₂C→CH₂, which serves via its C₂ fragment as an unprecedented four‐electron σ donor.     

On the long‐range relativistic effects in the 15N NMR chemical shifts of halogenated azines

Long‐range β‐ and γ‐relativistic effects of halogens in ¹⁵N NMR chemical shifts of 20 halogenated azines (pyridines, pyrimidines, pyrazines, and 1,3,5‐triazines) are shown to be unessential for fluoro‐, chloro‐, and bromo‐derivatives (1–2 ppm in average). However, for iodocontaining compounds, β‐ and γ‐relativistic effects are important contributors to the accuracy of the ¹⁵N calculation. Taking into account long‐range relativistic effects slightly improves the agreement of calculation with experiment. Thus, mean average errors (MAE) of ¹⁵N NMR chemical shifts of the title compounds calculated at the non‐relativistic and full 4‐component relativistic levels in gas phase are accordingly 7.8 and 5.5 ppm for the range of about 150 ppm. Taking into account solvent effects within the polarizable continuum model scheme marginally improves agreement of computational results with experiment decreasing MAEs from 7.8 to 7.4 ppm and from 5.5 to 5.3 ppm at the non‐relativistic and relativistic levels, respectively. The best result (MAE: 5.3 ppm) is achieved at the 4‐component relativistic level using Keal and Tozer's KT3 functional used in combination with Dyall's relativistic basis set dyall.av3z with taking into account solvent effects within the polarizable continuum solvation model. The long‐range relativistic effects play a major role (of up to dozen of parts per million) in ¹⁵N NMR chemical shifts of halogenated nitrogen‐containing heterocycles, which is especially crucial for iodine derivatives. This effect should apparently be taken into account for practical purposes.