铜铅合金轴瓦加锑对金相组织及使用性能的影响

本文针对铜铅合金轴瓦在熔铸中易产生铅偏析的问题,通过加入几种第三元素的对此分析,以及对加锑的研究,阐述了加入锑对于改善铜铅合金的金相组织和提高轴瓦使用性能的作用。     

细圆管内氧化铜颗粒悬浮液流动与对流换热的实验研究

实验研究了氧化铜纳米悬浮液在内径为0.68mm不锈钢细圆管内迫流动和对流换热。氧化铜纳米颗粒悬浮液的质量分数W为0.02-0.06，分别去离子水和水－纳米颗粒悬浮液的流动，传热特性进行了实验测定。实验结果表明：所研究尺度下，层流向湍流过渡早于常规大尺度流动，悬浮液的压降要大于去离子水的；纳米颗粒的质量分数越大，压力降也越大，悬浮液的对流换热系统随颗粒质量分数的增大而增大。     

Seismic Fragility of Steel Piping System Based on Pipe Size,Coupling Type,and Wall Thickness

In this study, a probabilistic framework of the damage assessment of pipelines subjected to extreme hazard scenario was developed to mitigate the risk and enhance design reliability. Nonlinear 3D finite element models of T-joint systems were developed based on experimental tests with respect to leakage detection of black iron piping systems, and a damage assessment analysis of the vulnerability of their components according to nominal pipe size, coupling type, and wall thickness under seismic wave propagations was performed. The analysis results showed the 2-inch schedule 40 threaded T-joint system to be more fragile than the others with respect to the nominal pipe sizes. As for the coupling types, the data indicated that the probability of failure of the threaded T-joint coupling was significantly higher than that of the grooved type. Finally, the seismic capacity of the schedule 40 wall thickness was weaker than that of schedule 10 in the 4-inch grooved coupling, due to the difference in the prohibition of energy dissipation. Therefore, this assessment can contribute to the damage detection and financial losses due to failure of the joint piping system in a liquid pipeline, prior to the decision-making.     

Effect of ultrasound on the true flotation of lignite and its entrainment behavior

In this study, the ultrasound was fixed in the pulp zone of flotation cell and its effect on the true flotation of lignite was analyzed. Flotation results indicated that the simultaneous ultrasound treatment increased the concentrate yield and decreased the concentrate ash content. Screening analysis of flotation products revealed that the ultrasound could crush coarse coal to fine coal and scanning electron microscopy (SEM) tests indicated that the ultrasound could reduce the coverage of high-ash coal fines on the coarse particle surface. Thus, the flotation recovery of coarse lignite particle was increased. In addition, the true flotation and entrainment of ?0.074 mm fine particles were studied by the sink-float test and the method of Trahar. It was found the ultrasound significantly enhanced the true flotation of fine particles and improved the overall water recovery in lignite flotation.     

海平面上宇宙射线电离量的测定及其影响因素的讨论

用自制的圆柱形钢壁充氩高气压电离室在三个不同海拔高度的湖面上,测量了宇宙射线电离量,进而外推出海平面上宇宙射线电离量值为(2.13±0.13)I。又根据在渤海海域的直接测量数据,与上述值比较,得出在渤海测量时所乘钢制船体的γ放射性影响为0.43I(相当于0.74μR/h)。对于测量中若干影响因素进行了初步分析和讨论,认为周围环境物质(例如钢制船体)中天然放射性核素的γ放射性和常压(1atm.)电离室室壁的α发射是影响海平面上宇宙射线电离量数据一致性的两个主要因素。     

Improvement of 19F MR image uniformity in a mouse model of cellular therapy using inductive coupling

Magnetic Resonance Materials in Physics, Biology and Medicine - Improve 19F magnetic resonance imaging uniformity of perfluorocarbon (PFC)-labeled cells by using a secondary inductive resonator...     

Effects of hydroxyl radical induced oxidation on water holding capacity and protein structure of jumbo squid (Dosidicus gigas) mantle

Protein oxidation is considered as an important issue in food preservation process. In the present study, the potential influence of protein oxidation on water holding capacity and protein structure of jumbo squid (Dosidicus gigas) mantle was investigated. After the hydroxyl radical oxidation, it was found that the carbonyl, surface hydrophobicity and dityrosine content of myofibrillar protein significantly increased (P < 0.05), while the content of total sulphydryl decreased significantly (P < 0.01). Meanwhile, the fluorescence intensity of squid was weakened, and the maximum absorption peak of fluorescence red shift as the H₂O₂ concentration increased. The sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) showed that not only the protein cross-linking but also degradation could have occurred. The content of α-helix decreased, the content of β-sheet, β-turn and the unordered structures increased after oxidation. In addition, oxidation resulted in a decrease in water holding capacity. Taken together, oxidation resulted in the damage of the myofibrillar structure, the increase in muscle loss rate and the decrease in water holding capacity.     

Biogenic amines and their producers in Akawi white cheese

The aim of this work was to study the biogenic amine content of brine‐ripened cheeses after one year of storage and then to investigate possible contaminating micro‐organisms with decarboxylase activity. The biogenic amine production of isolates was tested in vitro. The most frequent biogenic amines were putrescine, histamine and tyramine. The biogenic amine content detected in one cheese sample was above 120 mg/kg; this can be considered toxicologically relevant. Decarboxylase activity was found for 33 contaminating micro‐organisms. Isolates belonging to Bacillus licheniformis, Debaryomyces hansenii, Staphylococcus equorum and Serratia marcescens produced significant amounts of putrescine and cadaverine.     

掺杂Si-Al-K对钼粉及其烧结制品组织、性能的影响

研究了不同含量掺杂元素对钼粉形貌、烧结坯及钼丝微观组织的影响。研究表明，随着掺杂元素含量的升高，钼粉粒度逐步细化：在烧结过程中，掺杂元素在烧结坯形成非晶相的第二相粒子，并且随着掺杂元素含量的升高，第二相粒子的分布密度增大，使烧结坯晶粒得到细化；在加工过程中，烧结坯中的第二相粒子碎化为粒子串，粒子串分布于纤维晶界处，可改善钼丝性能。