Advanced Materials Research Vols. 217-218

Abstract: There are the similarities and the differences between wavelet transformation and traditional superposing and averaging method are discussed in de-noising ABR signal. Actually, it is easy to see that the advantage of wavelet transform, but it’s unbelievable to other people. In this paper, by spectral analysis, a quantity measurement estimate is given. So we can conclude that wavelet transform has better result than traditional superposing and averaging for noise removal.

Abstract: In order to achieve online monitoring about hot-state dimension of large-scale forgings, a new monitoring method has been developed in this paper. The large-scale barrel-type forgings heat conduction differential equation is deduced on the basis of the heat transfer. The functional form of heat conduction equation for large-scale forgings is established. Then the relationship between temperature and dimension is solved according to the variational principle. So the dimension of the large-scale forgings is monitored by combining the relationship between temperature and dimension. The temperature is measured by sensor. As a result, the online monitoring about hot-state dimension of large-scale forgings is achieved.

Abstract: Pristine multi-walled carbon nanotubes (P-MWNTs) were functionalized with 4-substituted benzoic acid via ‘‘direct’’ Friedel-Crafts acylation in mild reaction medium of polyphosphoric acid (PPA)/phosphorous pentoxide (P2O5). Raman spectroscopy, thermogravimetric analysis, transmission electron microscopy were applied in this paper to demonstrate that multi-walled carbon nanotubes inherently have functional groups on their surfaces as a result of the reaction. The overall evidence indicates that the 4-substituted benzoic acid functionalization of carbon nanotube can be achieved without oxidation as pre-treatment. Thus, aryl carbonyl moieties with different length of 4-substituted alkyl acyl amine functionalized MWNTs（F-MWNTs） can be synthesized simply, without disrupting the primary structures of the nanotubes.

Abstract: The problem of steel products corrosion is increasingly outstanding, which causes a serious waste of resources. This thesis focuses on the study of a new formula for rust removing, adding some additives such as, corrosion inhibitor, complex agent, surfactant into the acid liquor, which is able to remove the rust layer effectively and protect metal products, economic and applicable. Through many testing on different ratio of additives composition, we obtain the optimal formula.

Abstract: Based on the principle of a screw seal, a new type of seal consisting of a series of screw seals was developed and named as an axial pumping baffle seal. A theoretical analysis model was presented for such a seal which was developed to be used in nuclear coolant pumps. The feasibility of sealing high-pressure medium for such a seal had been proved. The variation of leakage rate and pressure distribution between a tooth and a sleeve with the number of seal stages and the geometrical parameters of screws was studied. The sealing mechanism was presented. The results showed that such a new seal maybe replace the first stage seal of a series mechanical seal used in a nuclear pump. When the number of screw seals is about 9, the reliability is ensured by the cooperation of the “attack” of the screw seal and the “defense” of the 180° sharp back bend.

Abstract: The effects of annealing temperature on the strength and corrosin properties of cold-rolled 5083 aluminum alloy (ε=60%）were investigated. The results show that the tensile strength of the alloy decreases with rising annealing temperature. The alloy shows ductile cracking in dry air and brittle cracking in 3.5%NaCl aqueous solution. The alloy reserves the most positive electrical potential at 200°C, and low SCC susceptibility at 200、250°C when annealed, but reserves relative high SCC susceptibility at 100, 150,300 and 350°C, which can be attributed to the difference shape and distribution of β-phase annealed at different temperature.

Abstract: Because of the terrain changes, the ice of foundation under the building and floating ice on the Yellow River often meet the stress. Therefore, research on the ice properties has important significance to ice dynamic processes of ice glaciers, rivers, lakes, sea ice and icebreaker. In this paper, the properties of artificial cylindrical ice is analyzed and researched. Prepared process of artificial cylindrical ice and the determination using pressure testing machine on artificial cylindrical ice are given, mainly including the production of frozen mold, the production and processing of ice samples and researching on the properties of the cylindrical ice. When frozen temperature is -10,-20,-30，-40°C, constant loading speed 1，3，5，7，10 mm/min is loaded with pressure testing machine on icicle, it can be concluded the influence of frozen temperature and loading speed on icicle.

Abstract: A single inlet and multi-inlet hollow fiber modules (HFMs) were designed in order to investigate the fluid hydrodynamics of the shell side. Residence time distribution (RTD) curves was measured under different packing density and inlet. Mean residence time ( ), variance( ) and the number of tanks (N) were also calculated to reflect the degree of backmixing. The experimental results indicated that the random packing of fiber caused the non-ideal flow in shell side. With the increasing of the packing density, the non-ideal flow was more serious. Contrasting to the traditional one, multi-inlet hollow fiber modules could weaken the trailing of the RTD curves and control the backmixing. With the quantity and the site of the inlets changed, non-ideal flow can be further improved. The hydraulic characterization of the shell side flow were related with not only the quantity but also the site of inlets. The results indicated that the muti-inlets design is superior to that of a single inlet.

Abstract: In this paper, several types of PVDF hollow fiber membranes used in the gas membrane separation process for extracting bromine from simulated seawater or concentrated seawater were studied. The micropore, hydrophobic property, mechanical strength and material chemistry of the PVDF membranes soaked in seawater or concentrated seawater were characterized by SEM-EDX, IR, contact angle testing instrument and electronic fabric strength tester, which were compared with those of origin membranes. At last, the mass transfer coefficient and flux during a long time were gained by operating a permeation experiment with a chosen type of PVDF membrane module.

Abstract: This paper describes a system that can automatically extract the topics from subjective Chinese sentences and identify their emotional tendencies. In the topic identification phase, the system bases on the dictionary containing the emotional words, dependency grammar and statistical pattern to identify the topic. In the sentiment identification phase, the system bases on the modifying relationship between the adverbs, negation words and emotional words to identify the emotional tendency. Finally, we choose a large number of Chinese sentences as our benchmarks to evaluate the system’s performance, analyze its error rate and propose directions for our future improvements.