Papers by Keyword: Formation Mechanism

Abstract: Pulverized coal combustion is one of the main NOx emission sources. The existing low NOx combustion technology can not meet the requirements of environment conservation. In this paper, a new low NOx combustion technology, the NOx inhibition method based on water-gas reaction, is presented, in which steam is injected into the anoxic flame of pulverized coal to bring water-gas reaction and produce CO and H₂ which will inhibit the production of NOx. The produced H₂ is especially very active. Water-gas reaction is endothermic, which has an effect of reducing the peak temperature of the flame and is very propitious to the inhibition of thermal type NOx. As the water-gas reaction is also an interim process, the heat absorbed in it will be released when burning with oxygen so that the whole amount of heat inside the furnace is not affected. The principle of the method is proved correct by experiments and industrial scale of 420 t/h boiler tests in which the effect of NOx reduction is obvious. The technology is consistent with that of air-staged combustion.

Abstract: Through analyzing Dabaoliang geological characteristics, this paper discussed the factors of the mechanism of landslide in Dabaoliang area and simulated its evolutionary process. The paper could get some conclusions, and the factors of landslide are as follow: the stability of the slope which mainly composed by clastic rock not only depended on the performance of the mudstone layer but also the skid resistance of the sliding surface and the shape of slope. Under the influence of regional structure, the joint fissures which developed along the boundary of the landslide will connect the crack and benefit the permeation of the surface water. The heavy rain is one of the main factors caused the slope unstable and sliding. Provide effective prevention and control for prevention and control of projects.

Abstract: In the present work, rapidly solidified Al-21Si-0.8Mg-1.5Cu-0.5Mn alloys strips was prepared by melt-spinning technique. The microstructure morphology and phase structures of experimental alloy were characterized by means of scanning electron microscopy (SEM), transmission electric microscopy (TEM) and XRD technique. The results show that the grains were refined and the micro-nanocomposite structural were formed under rapid solidification. The nucleation and growth of primary silicon were suppressed and primary silicon could not deposited, meanwhile, α-Al phase was nucleated which prior to eutectic. The microstructure of the Al-21Si alloy was composed of micro-nanostructured α-Al phase and feather-needles-like eutectic α-Al+β-Si phase. The hypereutectic Al-21Si alloy showed the hypoeutectic microstructure. The rapidly solidified Al-21Si alloy microstructure formation mechanism has also been discussed.

Abstract: Geopolymers were fabricated from some Japanese volcanic ashes. 30 g of volcanic ash with 200μm in diameter was mixed with 10 ml of sodium hydroxide solution with various concentrations to form slurry which became geopolymer after curing. When 8.5~11.5 mol/L of sodium hydroxide solution was used, the compressive strength of the resultant geopolymers reached to 25-35MPa. However, when the volcanic ash with high silica content was used, the compressive strength of the geopolymer was under 20 MPa. Furthermore, the addition of sodium silicate hydrate into starting slurry which was consisted of volcanic ash and sodium silicate solution had not effected on the compressive strength of geopolymer. In contrast, the compressive strength of the geopolymer decreased to 30 % of compressive strength compared to that of original geopolymer after water immersion for 3 days. However, crushing treatment of the volcanic ash contributed to retain the compressive strength. Actually, when 10μm of volcanic ash was used to fabricate geopolymer, the compressive strength improved to 70% compared to that of original geopolymer.

Abstract: This paper analyzed the large diameter Fresnel lens mold machining mechanism based on modal test methods .The design and mold machining principle of Fresnel lens were introduced . Explored the cutting speed and feed on chip formation process. The results show that: the material strength and plastic brittle have significant impact on chip morphology in the H62 brass mold processing, an improvement of material strength with the increase of strain rate and the evolution process of the chip can be divided into: ribbon cuttings, serrated chips, cell chips.

Abstract: Flame method is a new and simple method which may has the possibility of large-scale mass production for the synthesis of carbon nanotubes. It needs not the vacuum environment and carbon nanotubes can be captured at the normal atmospheric pressure. Synthesis of carbon nanotubes from the controllable flame is a new method. It can effectively avoid the defect of the traditional flame method. Experimental apparatus is mainly including controllable flame burner with its ancillary equipment, measuring instrument and catalyst preparation system, etc. The process of formation and growth for carbon nanotube is very complicated on account of the complexity of combustion and chemical reaction. It can be supposed that the formation and growth of carbon nanotubes from the controllable flame involves two steps in general.

Abstract: A research field on semi-solid metal processing is the preparation of semi-solid slurry with non-dendritic microstructure. Nowadays, with the technological innovation of semi-solid slurry preparation, people turn to produce the non-dendritic semisolid microstructure by locally cooling of the alloy melt during solidification. Therefore, it is necessary to investigate the formation mechanism of the non-dendritic microstructure formation because the primary phase undergoes a specially controlled nucleation and growth which distinctly different from the commom solidification. In this paper, the semisolid slurry of AM60 alloy was produced by Self-Inoculation Method (SIM), and the microstructure evolution of primary α-Mg was investigated by water quenching method and metallographic analysis. The results indicate that the semisolid microstructure of AM60 alloy produced by SIM composed of small and globular α-Mg particles, and these grains undergone a coarsing process during quiescent holding. The solid substrate caused by the fusion of solid particles and the dendritic fragments caused by melt flow caused the grain multiplication, and then the grain undergone a steadily growth because of the uniform temperature distribution, resulting in the increase of grains density and a small grain size of the AM60 semisolid slurry.

Abstract: The paper studied characteristic of the morphology, substance and formation mechanism of Suo Duoxi deposit body in the Su Walong hydropower station reservoir area, focused on analysis of substance composition and formation at front area of deposit body (zoneII) and finally inferred the geological formation process and reached the formation mechanism . The results show that the block stones are main part of material of Suo Duoxi deposit and sandwiches gravel soils, but it is different from other four zones that the zone II takes gravel with less viscous as the skeleton and mixed up with uneven sizes and irregularly shape stones. The forming reason of deposit is the landslides at left bank of Jinsha River and rockfall of the steep mountain back of the deposit body on the right back with the effect of weathering, rainfall and glacial erosion and so on. Geological formation process of deposit determined the geomorphic features, but also changed paleocurrent of Jinsha River.

Abstract: Formation mechanism of high-angle reverse faults has always been one of the questions concerning structural geologists. The mechanics of high-angle reverse faults does not conform to the Mohr-Coulomb criterion or Anderson’s theory of faulting. Geologists tried to explain the formation mechanism of high-angle reverse faults by inversion structure theory, Maximum Effective Moment Criterion and fault-valve model and so on. It is hard to explain the mechanism of high-angle reverse faults in Sanan oilfield with these viewpoints. It is considered that the cause of formation of such high-angle reverse faults was that the dip direction of normal fault plane has been overturned by the intensive superposed folding and interlayer gliding. “Overturned fault dip” can be regarded as a new type of inversion structure and supplements the existing types of inversion structure.

Abstract: This work aims to explore the sources of raw materials of archaic serpentine jade artifacts by comparing their trace element content. The major and trace elements of serpentine jade samples from different deposits in China are determined by external-beam proton-induced X-ray emission (PIXE). Trace element concentrations are also measured by inductively coupled plasma atomic emission spectroscopy for comparison. The relationship between the trace element content and the mechanism of serpentine formation is discussed. The results indicate that Type I jade has a small amount of Ni in it and almost no Cr and Co while significant amount of Cr, Co and Ni was found in Type II jade. Thus, this could be used to distinguish the two kinds of serpentine jade formed by different mechanisms.