The 600 °C Isothermal Section of the Al-Ni-Zn Ternary System

The 600 °C isothermal section of the Al-Ni-Zn ternary system was constructed based on wave dispersive x-ray spectrometry and x-ray power diffraction analysis. Eight three-phase regions have been identified in the Al-Ni-Zn ternary system at 600 °C. No new ternary compound was found in the system. The Liq. phase (η-Zn) can be in state of equilibrium with the Al₃Ni, Al₃Ni₂ and AlNi phases. The solubility of Ni in the Liq. phase is low, no more than 0.8 at.%. Binary phases AlNi and NiZn extend into the ternary system, and they co-exist in the Al-Ni-Zn ternary system at 600 °C. The three-phase triangles of (NiZn + AlNi + Ni₃Zn₁₄) and (AlNi3 + AlNi + NiZn) are constructed in this ternary system. As shown in this research result, the three-phase equilibrium relationship of the phases AlNi, Al₃Ni₅ and AlNi₃ has been confirmed in the present study.     

Changes in the phenolic contents and antioxidant activities of citrus peels from different cultivars after in vitro digestion

The aim of this study was to investigate the effects of in vitro digestion on the phenolic contents and antioxidant activities of citrus peels. Three different varieties of citrus peels (mandarin, ponkan and red tangerine) were treated with simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). The results showed that the SGF or SIF treatments of the citrus peels did not significantly increase the total phenolic content (TPC) or total flavonoid content (TFC), except for that of the TFC of ponkan peel treated with SGF. However, simulated in vitro digestion did improve the antioxidant activities measured with FRAP and ABTS methods. The effect of SGF was more positive than those of SIF for the FRAP assay, but the opposite was true for ABTS. Notably, both simulated digestion techniques decreased the DPPH free radical scavenging abilities. Simulated digestion in vitro changed the antioxidant activities of the citrus peels.     

Analysis of heat-transfer performance of cross-flow fin-tube heat exchangers under dry and wet conditions

A three-dimensional analysis procedure for the detailed phenomenon in a fin-tube heat exchanger has been developed and applied to predict the heat/mass transfer characteristics of the wave-fin heat exchangers. The continuity, Navier–Stokes and energy equations together with the species equation for the air–vapor mixture are solved in a coupled manner, so that the inter-dependence between the temperature and the humidity can be properly taken into account, by using the SIMPLE-type finite volume method. Having validated the procedure, calculations have been carried out for various frontal-velocity and inlet-humidity conditions. It has been shown that the flow characteristics, such as the temperature and humidity fields, along with the local heat flux and the condensation rate, can be successfully captured. The numerical results reveal that the existing correlations considerably underestimate the fin efficiency especially for multi-row heat exchangers. For dehumidifying cases, the sensible heat-transfer rate seems insensitive to the inlet-humidity change. The rate changes mostly in the narrow band of partially wet regime between 25% and 40% of inlet relative humidity. The range of the frontal velocity that gives the best performance for various numbers of rows is also estimated. The analogy between the heat and mass transfer on the fin surface is also examined.     

不同溶栓方法治疗心源性脑栓塞的对比研究

【摘要】 目的 了解不同溶栓方法治疗心源性脑栓塞患者的有效性、安全性。方法 66例心源性脑栓塞患者分为静脉溶栓组25例、单纯动脉溶栓组18例、机械辅助动脉溶栓组23例，评估不同溶栓方法治疗后血管再通率、NIHSS评分、GCS评分、Barthel指数（BI）优率、症状性颅内出血率及病死率。结果 3组患者治疗后的NIHSS评分、GCS评分均较治疗前明显提高（P < 0.05），机械辅助动脉溶栓组血管再通率（18/23，78.3%）、BI优率（10/25，40%）均明显高于静脉溶栓组（P ＜ 0.05）；单纯动脉溶栓组的症状性颅内出血率（1/18，5.6%）明显低于静脉溶栓组（8/25，32%）；病因分析发现，瓣膜性心脏病、黏液瘤所致脑栓塞的血管再通率低，颅内出血率和病死率高。结论 溶栓治疗可改善心源性脑栓塞的神经功能缺损，机械辅助动脉溶栓治疗效果较好。

     

Vibration sensitivity analysis of the ‘Butterfly-gyro’ structure

The ‘Butterfly-gyro’ is simple to manufacture with single sided electrostatic excitation and capacitive detection, and it is considered as one kind of the microgyroscope with high sensitivity due to its unique structure. This paper provides the sensitivity analytical model by solving the dynamic equations of motion and the design guidelines for microgyroscope with high sensitivity. Using Coriolis Effect and Newton’s second law, the dynamic equations are built. The sensitivity analytical model, including the denotations of Q factors and the resonant frequencies, is built. The approximate analytical expressions of Q factors and the resonant frequencies are derived by rational assumptions. Based on the sensitivity analytical model, the parametric analysis is carried out, and the design guidelines of high sensitivity are also deduced. Finally, Q factor, frequency split and other factors influencing the sensitivity are discussed in details to enhance its sensitivity. Results presented are valuable in the design and parameters optimization of the microgyroscope with high sensitivity.     

乔后盐矿斜井溶腔形状初探

斜井三管油垫单井开采在国内为数不多，探讨其溶腔形状及运行参数对安全生产、采矿量计算起到至关重要的指导作用。     

Development of Aerosol Sample Introduction Interface Coupled with ICP-MS for Direct Introduction and Quantitative Online Monitoring of Environmental Aerosol

Although much progress has been made on single particle analysis by inductively-coupled plasma-mass spectrometer (ICP-MS), many problems remain for online analysis of environmental aerosol by ICP-MS, such as aerosol direct introduction and response time. In this article, an aerosol sample introduction interface coupled with ICP-MS for direct introduction and quantitative online monitoring of environmental aerosol has been developed and characterized. Through the interface, sampling of environmental aerosol, matching of the sampling aerosol flow and the finally introduced flow, conversion of carrier gas from air-to-air–argon mixture, removal of water vapor and matrix gas, could all be implemented. Moreover, it supports the standard solution nebulization and addition method by which the transport efficiency and the instrumental sensitivity are calibrated totally in real time. Online analytical performance of ICP-MS coupled with the interface was evaluated. Results show that the response time for online monitoring of environmental aerosol improves dramatically as the aerosol sampling flow increases from 100 mL/min to 1 L/min. The sensitivity is improved through condensation growth and concentration enrichment process. The background equivalent concentration of ²³⁸U in aerosol is 1.1 × 10^?9 g/m³. As a preliminary comparison study, uranium concentration in environmental aerosol in a clean room was monitored by online and offline methods.

Copyright 2014 American Association for Aerosol Research