Dielectric reference coatings for the evaluation of thin film characterization techniques

Thin film technology has an increasing demand for industrial reliable characterization techniques. A precise absolute determination of layer thickness, interface width and the quantification of depth profiles in dependence on resolution limits of the measurement are required. Certified reference materials, certified reference coatings (CRCs) and non-destructive evaluation techniques can meet these requirements. Dielectric reference coatings (SiO₂, Si₃N₄) were used for metallographic preparation (e.g. bevelled cross-sections), optical characterization techniques (e.g. spectroscopic ellipsometry (SE)), and films of SiO₂, Si₃N₄ and Al₂O₃ were applied to reference measurements in depth profiling of layer stacks (e.g. radio frequency glow discharge optical emission spectroscopy). Thickness and refractive index of these dielectric single-and multilayer coatings on different substrate materials are accurately determined in advance by means of SE. These values are subsequently used for precise angle determination of bevelled cross-sections, for reference and re-calibration purposes in thin film characterization (system reproducibility) and in surface analysis (determination of sputter and erosion rates, depth profiles). Examples are discussed for different applications and the calculated data are compared with experimental results. It is shown that reproducible commercial coatings are also of importance for use as CRCs.     

Comparison of the contribution of formaldehyde and lipid oxidation products to protein denaturation and texture deterioration during frozen storage of minced ice-fish fillet (Champsocephalus gunnari and Pseudochaenichthys georgianus)

Fillets of the ice-fish Champsocephalus gunnari and Pseudochaenichthys georgianus were minced and mixed with various additives to induce the formation of formaldehyde and oxidation of lipids. The mixtures were frozen and stored for several months and protein denaturation and changes in texture were measured. Samples containing high concentrations of formaldehyde were very tough in texture. However it was found that even severe lipid oxidation (up to 14 mg of malonaldehyde per kg wet mass) had only a slight influence on texture.     

Modeling incidence of lipid and sodium chloride contents on sorption curves of gelatin in the high humidity range

Water mobility and availability are predominant factors in controlling organoleptic and biological quality in food. To characterize and quantify the role of protein macromolecular mesh, sodium chloride and fat on the water retention in the high humidity range, sorption isotherms were measured at 20 °C. A specific method was used which provides rapid equilibrium and many experimental points in comparison with the standard saturated salt solution method. Experiments were carried out on gelatin gels to which either sodium chloride (0-45% w/w on an anhydrous gelatin basis) or vegetal hydrogenated fat (0-50% w/w on total sample mass) was added. Desorption isotherms of 40 points each were measured for each sample for a_w values in a range from 0.60 to 0.99. Results precisely show the specific behavior of water in a protein-sodium chloride mix for a_w values between 0.65 and 0.75. Water activity was then predicted from sample composition. Good agreement with measurements was obtained (1) assuming no incidence of lipids on water-holding capacity and (2) adapting a Ross-type model considering crystallization and introducing an interaction factor related to sodium chloride content.     

Effect of pH and ionic strength on phospholipid nanomechanics and on deposition process onto hydrophilic surfaces measured by AFM

The effect of ion-binding on a zwitterionic phospholipid such as 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) has been studied by measuring the zeta potential value of the unilamellar liposomes present in solution while varying the pH and the ionic strength in independent experiments. We have experimentally confirmed that DMPC binds cations, resulting in an increase of the zeta potential value. The liposome surface charge has been proved to have a strong effect on the supported bilayer formation on hydrophilic, negatively charged surfaces such as mica and silicon oxide as atomic force microscopy images reveal. Furthermore, thanks to force spectroscopy measurements we have proved that ion-binding also affects the nanomechanical response of the system, since it increases the force that has to be exerted on the membrane in order to puncture it. Last but not least, the nanomechanics of the bilayer does not depend on the substrate, thus implying that membrane properties are not influenced by the supporting material.     

Acute ingestion of yerba mate infusion (Ilex paraguariensis) inhibits plasma and lipoprotein oxidation

Yerba mate extract (Ilex paraguariensis) is a source of phenolic compounds that possesses in vitro antioxidant activities and may contribute to a reduction in the risk of cardiovascular disease. In this study we examined the acute effects of the consumption of mate infusion on ex vivo plasma and low-density lipoprotein (LDL) oxidation, plasma antioxidant capacity, and platelet aggregation. Twelve healthy fasted subjects ingested 500 mL of mate infusion and blood samples were collected before and 1 h after mate intake. Lipid peroxidation of plasma and LDL was monitored by the measurement of cholesteryl-ester hydroperoxides (CE-OOH) and cholesterol oxides. The plasma antioxidant capacity was measured as ferric-reducing antioxidant potential (FRAP). Platelet aggregation was evaluated in platelet-rich plasma stimulated with adenosine diphosphate and coagulation was tested in platelet-poor plasma. Ingestion of mate infusion diminished the ex vivo oxidizability of both plasma and LDL particles. After mate intake, the CE-OOH levels were around 50% lower in plasma oxidized with copper or 2,2′-azobis[2-amidine-propane-hydrochloride] (AAPH) and the lag time to plasma oxidation increased 2-fold (P < 0.05). Copper- and AAPH-induced LDL peroxidation were also inhibited by around 50% and 20%, respectively, after mate consumption (P < 0.05). The levels of various oxysterols were significantly reduced in oxidized-plasma and LDL (P < 0.05) and FRAP increased by 7.7% after mate intake (P < 0.01). However, mate consumption did not inhibit platelet aggregation or blood coagulation. In summary, intake of yerba mate infusion improved the antioxidant capacity and the resistance of plasma and LDL particles to ex vivo lipid peroxidation.     

A Novel Flow Profiling Approach Using Permanent Downhole Pressure Gauges

Flow profiling through permanent downhole pressure gauge, a novel and unique application, is proposed in the present paper. Theoretical development of the new technique is first provided. Example studies are then given to illustrate the application of the technique. Application scenarios, practical issues, as well as key impacting parameters are also addressed. Finally, a field case study implementing the new technique for a long horizontal well is performed to demonstrate how the production profiles calculated from permanent downhole gauge (PDG) data compare closely to the results from a recent production logging (PLT) survey which was expensive and mechanically risky yet turned out to be unsatisfactory.

The technique could be applied to real-time production and injection profiling for different well configurations (vertical, horizontal, deviated, and multilateral) and bring tremendous financial benefits through replacing conventional production logging surveys that could be cost-extensive for horizontal or multilateral wells offshore.     

基于多体系统理论的反弧门钢止水修复误差分析

以自制反弧门钢止水修复设备为研究对象,通过分析反弧门钢止水非线性接触密封面机械同步仿形修复误差产生的原因,运用多体系统理论建立了反弧门钢止水非线性接触密封面机械同步仿形修复误差的数学模型,找出了修复过程中的全部误差项,并得出修复过程中的主要误差为原理性误差、导轨精度误差、设备误差、砂轮磨损误差。该模型能为修复设备的优化设计提供参考依据,对反弧门钢止水修复误差补偿及修复精度的提高具有指导意义。