气液两相流气泡图像的形态学分割方法

针对气液两相流图像中的气泡粘连现象,提出了一种用于识别粘连气泡的图像分割新算法。首先利用差影算法消除背景噪声,利用最佳阈值分割法将其二值化;然后采用形态学填充算法对气泡中心区域进行填充,并利用填充图像减去原二值化图像,从而分离出气泡的亮点图像;最后用形态学条件加厚算法对每个亮点进行重复加厚处理,得到气泡的分割图像。试验结果表明,该算法可以对气液两相流中的粘连气泡图像进行有效的分割识别,以便进一步准确地测量气泡尺寸及截面含气率。     

Hard sphere behaviour of arborescent polystyrenes: viscosity and differential scanning calorimetry studies

Two series of arborescent polystyrenes were prepared by successive cycles of functionalization and anionic grafting reactions. A target branching functionality of around 15 side chains per backbone chain and a constant branch molecular weight of either 5000 g mol⁻¹ (S05 series) or 30 000 g mol⁻¹ (S30 series) were used for each generation. The intrinsic viscosity of each polymer series was relatively insensitive to molecular weight, a behaviour typical of hard spheres. The S30 polymers expanded considerably in toluene relative to cyclohexane, but the S05 polymers were unaffected by change in solvent quality. Analysis by d.s.c. showed that limiting T_g values are reached in the upper generations of each polymer series, similarly to polymer networks prepared from primary chains with a low molecular weight. A lower ΔC_p and a broader transition range observed for the upper generation S05 polymers may be related to a decrease in chain mobility inside the molecules. No similar effects were observed in the S30 polymers. © 1997 Elsevier Science Ltd.     

凝固过程数值模拟的可视化研究

将凝固模拟迭代计算的数值结果以可视化的方式表现出来，让画面真实直观，让显示透彻动感，这是直接关系到凝固模拟技术实用效果的至关重要的环节 。介绍凝固模拟图形像表实意方式设计和动态演示中的一些思路和技术要点。     

Effects of filgrastim on granulopoietic cells of mice pretreated with methotrexate.

We have evaluated the effect of filgrastim on proliferation and differentiation activity of granulopoietic cells in mice pretreated with methotrexate. Filgrastim was injected daily, from day 8 to 28 after cytotoxic agent administration. The granulopoiesis changes were measured by assessment of GM-CFU cells content, marrow and spleen granuloid cells pool as well as circulating neutrophils. In MTX pretreated mice, bone marrow GM-CFU oscillating values were higher than normal values, but these changes were not followed by high proliferative activity in granuloid precursor cell compartment. After MTX treatment, filgrastim administration was unable to stimulate marrow granulopoiesis as observed in normal mice. In the spleen, MTX led to dramatic changes in the proliferative activity of GM-CFU cells, but did not result in spleen granuloid cell changes. However, filgrastim treatment induced a spleen granuloid amplification, similar to the changes observed in circulating neutrophils values. We suggest that these findings can be explained by inhibition of differentiation of marrow GM-CFU cells into the more mature granulopoietic cells and/or by an inhibited proliferative activity of marrow granuloid cells. They can be also explained in terms of an unfavorable marrow microenvironment for granulopoiesis, contrary to a supportive spleen microenvironment.     

玉米须提取物对食品腐败菌及致病菌抑制作用的研究

首次以玉米须提取物对七种常见的食品腐败菌及致病菌进行抑菌试验,发现玉米须的乙醇提取物的效果最好,其最低抑菌浓度（ＭＩＣ）为３．０ｇ／１００ｇ。此外,对食品加工条件（如杀菌方式等）及食品介质（如ｐＨ）对玉米须提取物抑菌活性的影响也作了研究。结果表明。玉米须提取物在常规食品杀菌条件（ＵＨＴ）及中酸到酸性环境下抑菌活性稳定,因而可做为潜在的食品防腐剂。     

Deasphalting process using supercritical water

The authors aimed to study the deasphalting process on laboratory scale through the design and development of a supercritical extraction experimental unit. The experimental unity used in tests is composed by a pump, an extractor with useful volume of 3 L and one separator vessel. Extractions in supercritical condition were carried out using petroleum residue (vacuum residuum) as feedstock and water as solvent. Temperature and pressure were manipulated to maintain the solvent in the required conditions, thus facilitating the extraction process and avoiding sharp changes in the system. In both phases, the products in the deasphalted oil stream present adequate characteristics for the production of lubricant oils and those in the asphalt residue stream present an elevated concentration of asphalt molecules.     

Dual temperamental risk factors for psychopathic personality: Evidence from self-report and skin conductance.

Psychopathy is a personality disorder consisting of dysfunctional affective interpersonal features (Factor 1) and impulsive-antisocial behavior (Factor 2) that exhibit differential associations with palmar skin conductance (SC) reactivity. The goal of this study was to determine whether the distinct SC reactivity observed in incarcerated psychopaths generalizes to university students who score high on personality dimensions hypothesized to be the risk factors for these psychopathy factors. Lilienfeld's Psychopathic Personality Inventory (PPI; Lilienfeld & Andrews, 1996) was used to compute scores on 2 factor-analytically derived dimensions that have been the focus of recent research in psychopathy. PPI-1 is hypothesized to relate to the low-fear temperamental risk factor, whereas PPI-2 is hypothesized to relate to regulatory dysfunction. SC reactivity was measured during tasks previously used in studies of diagnosed psychopaths. Results indicated that PPI-1 was associated with reduced SC during anticipation of an aversive noise and PPI-2 was associated with enhanced SC reactivity during presentation of a speech about one's faults. Additional analyses explored an 8-factor solution of the PPI and 3 temperament dimensions derived from factor analysis of several personality measures. Together, the SC results suggest that the Factor 1 pathway, best captured with refined assessments of behavioral fearlessness, related to reduced SC reactivity to an aversive noise—consistent with a weak defense system. The Factor 2 pathway, best captured by higher order dimensions reflecting externalizing, disinhibited forms of negative temperament, related to enhanced SC reactivity to a speech stressor—consistent with high stress reactivity. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Chiral Phosphoric Acid‐Catalyzed Enantioselective Three‐ Component Aza‐Diels–Alder Reactions of Aminopyrroles and Aminopyrazoles

A highly stereoselective three‐component Povarov reaction, catalyzed by (R)‐ and (S)‐BINOL hydrogen phosphate, was achieved for the first time with aminopyrroles and aminopyrazoles as 2‐azadiene precursors. A variety of aldehydes, enecarbamates, amino‐substituted azines participated in the reaction to afford the tetrahydropyrrolopyridines and tetrahydropyrazolopyridines in good yields with excellent diatereo‐ and enantioselectivities. A stereochemical model is proposed to account for the observed absolute stereochemistry.

     

Encapsulation of nisin and lysozyme in liposomes enhances efficacy against Listeria monocytogenes

The efficacy and stability against Listeria monocytogenes of nisin and lysozyme encapsulated in phospholipid liposomes was evaluated. Antimicrobial-containing liposomes were prepared by hydrating dried lipids with buffer containing nisin, nisin plus the fluorescence probe calcein, or calcein and lysozyme. Mixtures were then centrifuged and sonicated, and encapsulated liposomes were collected using size-exclusion chromatography. Antimicrobial concentration in liposomes was determined by bicinchoninic acid assay prior to determination of antimicrobial activity against strains of L. monocytogenes. When nisin was encapsulated in liposomes, protein concentrations of 0.39, 0.27, and 0.23 mg/ml for phosphatidylcholine (PC), PC-cholesterol (7:3), and PC-phosphatidylglycerol (PG)-cholesterol (5:2:3), respectively, were obtained. Encapsulation of nisin with calcein yielded protein concentrations of 0.35, 0.39, and 0.28 mg/ml for PC, PC-cholesterol, and PC-PG-cholesterol, respectively. Encapsulation of calcein with lysozyme resulted in protein concentrations of 0.43, 0.26, and 0.19 mg/ml for PC, PC-cholesterol, and PC-PG-cholesterol, respectively. Encapsulated nisin in 100% PC and PC-cholesterol liposomes inhibited bacterial growth by >2 log CFU/ml compared with free nisin. Growth inhibition with liposomal lysozyme was strain dependent, with greater inhibition observed for strains 310 and Scott A with PC-cholesterol and PC-PG-cholesterol liposomes. Inhibition of L. monocytogenes indicated the potential of liposomes to serve as delivery vehicles for antimicrobials in foods while improving stability of antimicrobials.     

Reverse osmosis technology for water treatment: State of the art review

This paper presents a review of recent advances in reverse osmosis technology as related to the major issues of concern in this rapidly growing desalination method. These issues include membrane fouling studies and control techniques, membrane characterization methods as well as applications to different water types and constituents present in the feed water. A summary of the major advances in RO performance and mechanism modeling is also presented and available transport models are introduced. Moreover, the two important issues of RO brine discharge and energy costs and recovery methods are discussed. Finally, future research trends and needs relevant to RO are highlighted.