A method for observing the three-dimensional morphologies of inclusions in steel

A method for observing the three-dimensional morphologies of inclusions by deeply eroding a steel sample with a kind of organic solution composed of bromine water, acetone, and HCl (volume ratio, 45:45:10) was introduced. Four different kinds of inclusions in ultra low carbon steel were compared by metallographic observation and erosion observation. The results show that the three-dimensional morphologies of different kinds of inclusions could be observed clearly and simply after erosion. The method is useful for the observation and analysis of inclusions made by deep erosion. It also provides a new way to control and remove inclusions based on the true morphologies of inclusions.     

Precipitation and control of BN inclusions in 42CrMo steel and their effect on machinability

The precipitation and control of boron nitrogen (BN) inclusions in 42CrMo steel were investigated and their effect on machinability was analyzed. First, the precipitation regularity of BN in 42CrMo steel was studied by theoretical calculation. Then, the machinability of the steel was investigated through contrast cutting experiments, and the composition and cooling rate of the steel were controlled to analyze the variation laws of the size, distribution, and area ratio of BN inclusions. Finally, the results were combined with the machinability of the steel to analyze the relationship among them. It is found that the machinability of the steel is mainly influenced by the diameter and quantity of BN inclusions. Fine and dispersedly distributed BN inclusions are more beneficial for the improvement in machinability of 42CrMo steel than coarse and sparse BN inclusions.     

Adsorption of Fluoride Ion by Inorganic Cerium Based Adsorbent

Excess of fluoride in drinking water is harmful to human health, the concentration of F^- ions must be maintained in the range of 0.5 to 1.5 mg/L. An inorganic cerium based adsorbent (CTA) is developed on the basis of research of adsorption of fluoride on cerium oxide hydrate. Some adsorption of fluoride by CTA adsorbent experiments were carried out, and results showed that CTA adsorbent has a quick adsorption speed and a large adsorption capacity. Adsorption follows Freundlich isotherm, and low pH value helps fluoride removal. Some physical-chemical characteristics of CTA adsorbent were experimented, fluoride removal mechanism was explored, and results showed that hydroxyl group of CTA adsorbent played an important role in the fluoride removal.     

Investigating Dependences in Packet-queues

Many packet communication networks carry several classes of traffic, each with its own service characteristics. The packet arrival processes from each source are also often bursty (highly variable), which can contribute to long packet delay. Associated dependence among successive service times and between service times and inter-arrival times also can be for packet queues involving variable packet lengths. These dependence effects are demonstrated analytically by considering a multi-class single server queue with batch Poisson arrival process.     

δ^13C and water-use efficiency indicated by δ^13C of different plant functional groups on Changbai Mountains,Northeast China

Leaf δ^13C of different plant functional groups （trees, shrubs and forbs; evergreen and deciduous; annual, biennial and perennial） were examined on the Changbai Mountains, China. Life form has a significant influence on plant δ^13C, suggesting that leaf δ^13C is also ideal for distinguishing functional groups species in temperate and frigid zones with high humidity. Additionally, the difference of water-use efficiency （WUE） is significant among different plant functional groups. δ^13C and WUE are in the following order of forbs 〈 shrubs 〈 trees. Within shrubs, δ^13C and WUE are higher for evergreen shrubs than deciduous shrubs. Differences in δ^13C and WUE are significant among different lifespan herbs, and δ^13C and WUE follow the order of annual herbs 〉 biennial herbs 〉 perennial herbs, not in accordance with the pattern obtained by previous studies in deserts, suggesting that the ranking of δ^13C and WUE among annual, biennial and perennial herbs may be dependent on local water availability.     

Effect of the microstructure of Al 7050-T7451 on anodic oxide formation in sulfuric acid

The effect of the microstructure of an Al 7050-T7451 substrate on the anodic oxide formation in sulfuric acid was studied in this article. The microstructure of the substrate was assessed by optical microscope (OM) and transmission electron microscope (TEM). The surface and cross-section morphologies of the oxide films were examined by scanning electron microscope (SEM). The chemical composition of intermetallic particles in the alloys and films was investigated using energy dispersive spectroscope (EDS). The roles of intermetallic phases and grain or subgrain boundaries on the oxide film formation were researched using the potentiodynamic and potentiostatic polarization technique in sulfuric acid solution. The results show that the transition of coarse intermetallic particles or grain (subgrain) boundaries at the surface of Al alloys can be characterized by potentiodynamic polarization curves. The surface and cross-section micrographs of the anodic layer seem to preserve the microstructure of the substrate. Large cavities in the anodic films are caused by the preferential dissolution of coarse AItCuMg particles and the entrance of Cu-rich remnants into the electrolyte during anodizing. The Al₇Cu₂Fe particles tend to be occluded in the oxide layer or lose from the oxide surface because of peripheral trenching. Small pores in the films are induced by the dissolution of precipitates in grain or subgrain boundaries. The film surface of recrystallized grain bodies is smooth and homogeneous.     

Effects of chromium on the corrosion and electrochemical behaviors of ultra high strength steels

The effects of chromium on the corrosion and the electrochemical behaviors of ultra high strength steels were studied by the salt spray test and electrochemical methods. The results show that ultra high strength steels remain martensite structures and have anodic dissolution characteristic with an increase of chromium content. There is no typical passive region on the polarization curves of an ultra high strength stainless steel, AerMet 100 steel, and 300M steel. However, chromium improves the corrosion resistance of the stainless steel remarkably. It has the slowest corrosion rate in the salt spray test, one order of magnitude less than that of AerMet 100 and 300M steels. With the increase of chromium content, the polarization resistance becomes larger, the corrosion potential shifts towards the positive direction with a value of 545 mV, and the corrosion current density decreases in electrochemical measures in 3.5wt% NaCl solutions. Because of the higher content of chromium, the ultra high strength stainless steel has a better corrosion resistance than AerMet 100 and 300M steels.     

Acid sensing by the Drosophila olfactory system

The odour of acids has a distinct quality that is perceived as sharp, pungent and often irritating. How acidity is sensed and translated into an appropriate behavioural response is poorly understood. Here we describe a functionally segregated population of olfactory sensory neurons in the fruitfly, Drosophila melanogaster, that are highly selective for acidity. These olfactory sensory neurons express IR64a, a member of the recently identified ionotropic receptor (IR) family of putative olfactory receptors. In vivo calcium imaging showed that IR64a+ neurons projecting to the DC4 glomerulus in the antennal lobe are specifically activated by acids. Flies in which the function of IR64a+ neurons or the IR64a gene is disrupted had defects in acid-evoked physiological and behavioural responses, but their responses to non-acidic odorants remained unaffected. Furthermore, artificial stimulation of IR64a+ neurons elicited avoidance responses. Taken together, these results identify cellular and molecular substrates for acid detection in the Drosophila olfactory system and support a labelled-line mode of acidity coding at the periphery.     

Large-scale genome-wide association studies in East Asians identify new genetic loci influencing metabolic traits

To identify the genetic bases for nine metabolic traits, we conducted a meta-analysis combining Korean genome-wide association results from the KARE project (n = 8,842) and the HEXA shared control study (n = 3,703). We verified the associations of the loci selected from the discovery meta-analysis in the replication stage (30,395 individuals from the BioBank Japan genome-wide association study and individuals comprising the Health2 and Shanghai Jiao Tong University Diabetes cohorts). We identified ten genome-wide significant signals newly associated with traits from an overall meta-analysis. The most compelling associations involved 12q24.11 (near MYL2) and 12q24.13 (in C12orf51) for high-density lipoprotein cholesterol, 2p21 (near SIX2-SIX3) for fasting plasma glucose, 19q13.33 (in RPS11) and 6q22.33 (in RSPO3) for renal traits, and 12q24.11 (near MYL2), 12q24.13 (in C12orf51 and near OAS1), 4q31.22 (in ZNF827) and 7q11.23 (near TBL2-BCL7B) for hepatic traits. These findings highlight previously unknown biological pathways for metabolic traits investigated in this study.     

A new species from an ornithuromorph（Aves： Ornithothoraces）dominated locality of the Jehol Biota

We report on a new species of ornithuromorph bird, Iteravis huchzermeyeri gen. et sp. nov., from the previously unreported Sihedang locality of the Lower Cretaceous Yixian Formation, the oldest ornithuromorph bearing deposit in the world. Unlike most other Cretaceous localities, specimens from this new quarry are largely referable to Ornithuromorpha, similar to the Lower Cretaceous Aptian Xiagou Formation in Gansu Province. Also similar to the Xiagou avifauna, the fauna at Sihedang is largely dominated by a single taxon（described here）.Differences in faunal dominance may suggest the Sihedang records a unique ecological habitat. This may also explain the dominance of Gansus in the younger Xiagou Formation locality and suggests that previous hypotheses regarding the shift in dominance between Enantiornithes and Ornithuromorpha need to be reassessed in terms of potential ecological biases due to limited sampling. Furthermore, the recognition of an ornithuromorph dominated locality in the Sihedang significantly weakens the signal of such an inferred trend. Compared to most Jehol birds, the new specimen is relatively better preserved in three dimensions revealing morphological details of the skeleton, as well as preserves feather impressions including a rectricial morphology previously unknown among Mesozoic birds.