Search

Tuyere raceway was known as the "engine" of the blast furnace, which plays a very important role, but it is very difficult to be directly measured and researched, because of limitation of experimental methods. In this paper application of kinetic theory of granular flow,coke particles as a pseudo-fluid, the two-phase raceway model of gas-solid was constructed by used of Eulerian two-fluid theory, and the model was verified correct.

Organic-inorganic hybrid silica were prepared via surfactant-mediated assembly of 1,2-bis (triethoxysilyl) ethane in a modified stöber process. Factors that affect the size of silica particles were investigated in detail. It is found that larger silica spheres are obtained under lower surfactant concentration, higher ammonia concentration and lower synthesis temperature; The size and dispersibility of silica particles also depend strongly on the amount of water in the mixture.

Various hydrophobic groups were used to modify the silica membranes by the co-hydrolysis and condensation of 1,2-bis(triethoxysilyl)ethane and alkylsilanes. The hydrophobic property and surface roughness of silica membranes were characterized by water contact angle measurement and atomic force microscope, respectively. The results show that the hydrophobic property of modified silica membranes increases with increasing concentration of alkylsilane in the mixture, increasing surface roughness and increasing length of carbon chain in the alkyl groups.

Morphological development of rill at hillslope formed a microrelief dynamic response system with soil erosion driven by rainfall. To reveal the formation mechanism of this system, scientifically quantification is the key problem. In recent years, domestic and foreign scholars had achieved fruitful results in rill evolution and quantized fields. This paper analysised the existing problems in the present research based on summarizing the current existing methods of rill morphology quantitation, and put forward the research direction in the future.

Analysising twenty-one silt dams in Jiuyuangou watershed and thirty-six silt dams in Tuwei River Watershed drilling hole sampling’s data, Jiuyuan gou Watershed’s silt dams in coarse sand size mainly concentrated in the 0.05mm,Tuwei River Watershed’s silt dams in coarse sand size mainly concentrated in the 0.05mm~0.10mm,The dam upstream sand size is generally larger than the dam downstream, sorting depends on sediment dam on the dam upstream tosand size, dam upstream sediment grain size is coarse separation effect is better, warping dam and reduction effect is more obvious.

In this paper, a finned tube condenser performance test platform by using hot water as heat transfer medium in the pipe was established. The air side correlations of pressure drop and heat transfer were acquired based on lots of testing datas.A segment by segment model of the finned tube condenser used in these correlations was proposed and a simulation program was developed by using Visual C++ programming tools. Experiment and simulation results show that the air side correlations of pressure drop and heat transfer are fitting well with experimental datas. The deviation between the experimental and calculated values is within ±5%.The deviation of Nu Number is within ±10% and the deviation of the pressure loss is within±15%.

In this study, three kinds of single-layered spunbonded nonwovens with different specifications were prepared as materials. The relation between layer number and pore structure (morphology characteristics, pore size and pore distribution, and Solid Volume Fraction) was studied. The results show that mean pore size decreases as layer number increases and the degree tends to be gentle. But the change law of maximum pore size is not obvious. Furthermore, pore size distribution of single-layered or two-layered nonwovens is concentrated and further increase in layer number doesnt have obvious effects on it . Air permeability reduces when the layer number increases and the variation trend accords with that of mean pore size.

A novel method was proposed to form porous silicon (PS) antireflection layers and thin SiO2 films at the same time by HF/H2O2 treatment of acid-textured pn+ multicrystalline silicon. Porous silicon structures formed inside the cavities and the porosity became large with an increase of the treated time resulting in a dramatical decrease of reflectance. The reflectance decreased to less than 5% within the wavelength range of 420-970 nm after 5 min HF/H2O2 treatment. Furthermore, the minority-carrier lifetime showed an increase of about 42% for a short treated time because of the formation of a thin silicon oxide layer resulting the reduction of dangling silicon bonds in the interface between PS/Si.

In vehicle navigation system, path matching often go wrong when road condition is complex, especially there are island ring, or exit and entrance of highway. This lead to wrong map display and wrong route guidance, thus system give a bad impact to driver. In order to solve this problem, this paper includes a map matching algorithm based on curvature and slope. This Algorithm coding has been realized by c and proved its availability at last.

A series of abnormal phenomena emerging in normal operation conditions of the medium speed pulverizers in a 600 MW unit are introduced. The effects of the primary air (PA) mass flow and nozzle ring passage area on the pulverizer rejects (PRs) discharge are analyzed. The results indicate that the root cause of all these abnormal phenomena is the lower nozzle PA velocity led by the narrowed nozzle passage area during the nozzle ring reformation. The problem is solved by changing the nozzle ring back to the original one. The experiences in this document can provide evidence and reference for pulverizer operation adjustment and PA nozzle ring reformation design.

A novel sensing element for direct detection of L-Tryptophan (L-Trp) in human serum was proposed by combination of electrochemical transduction and molecular imprinting technique. The sensing element was prepared by electropolymerization of o-phenylenediamine (o-PD) on the gold electrode in the presence of template L-Trp. The electrochemical property of the sensor was characterized by differential pulse voltammetry (DPV). The linear response range of the sensor for L-Trp concentration was 1×10-8 mol/L~21×10-8 mol/L with a detection limit of 0.3×10-8 mol/L. The results show that this approach has the potential to generate a universal inexpensive assay methodology of high sensitivity, specificity and simplicity to detect L-Trp.

Low cost electrochemical etching method was utilized to prepare macroporous silicon on p-type silicon substrate in dilute HF solution. By optimizing the substrate resistivity, the etching current density, and the etching time, excellent macroporous silicon was obtained on 15 Ω•cm p-type silicon substrate with the pore diameter of about 2 μm, the pore depth of about 30 μm, and the surface pore density up to ~107/cm2. Such macroporous silicon gave out an excellent antireflective performance with the reflectance lower than 4% in a wide spectral range of 400-1000 nm. The low reflectance combined with the deep pore morphology provides an attractive potential to fabricate radial p-n junction solar cells on such macroporous silicon.

Macroporous silicon was fabricated by electrochemical etching in hydrogen fluoride (HF) electrolyte on P-type silicon wafers. By optimizing the etching condition, the obtained macroporous silicon presented pore diameter of about 2 μm and pore density of ~107/cm2. Such macroporous silicon gave out an excellent antireflective performance with the reflectance lower than 4% in a wide spectral range of 400-1000 nm. An a-Si:H/c-Si heterojunction solar cell was fabricated on such macroporous silicon to show its application potential.

The difficulty of measuring the run-out of engine valve seat related to the centerline of the valve guide is the determination of the datum axis. A method that the gauge was fixed on the conical surface of the valve seat was chosen. One sensor on the conical surface of the gauge measures the run-out of the valve seat related to the centerline of the gauge. Another two sensors of the gauge measures the centerline of the valve guide. The mathematic model of measurement is established, the run-out of the valve seat related to the centerline of the valve guide can be archived.

In the laboratory condition, a series of experiments were carried out in a sintering pot in order to improve the tumbler strength of low SiO2 sinter. The results shows that the content of SiO2 is decreased from 4.4wt% to 3.9wt% when the ratio of serpentine is decreased from 2.2wt% to 1.0wt%, as a result, the tumbler strength and the reduction degradation index of sinter all fall down. When the ratio of serpentine is further decreased, all kinds of sintering indexes fall down rapidly. If the basicity of sinter is increased from 1.75 to 1.85, and 5wt% iron concentrate is added in sintering mixture, the content of SiO2 can be decreased to 3.9wt%~4.0wt%, meanwhile, the tumbler strength of sinter is the same as that of the reference sinter with 4.4wt% SiO2. When Niuman iron ore, Hainan iron ore and Hamosili iron ore are used as the hearth layer instead of sinter, and the basicity of sinter is increased to 1.85, the tumbler strength of sinter with 3.9wt%~4.0wt%SiO2 is the same as that of the reference sinter with 4.4wt% SiO2.

In this study, the simultaneous adsorption characteristics of ammonium and phosphate from aqueous solution by calcium chloride-modified zeolite were investigated. Results showed that the adsorption kinetic data of ammonium and phosphate onto the calcium chloride-modified zeolite could be well described by a pseudo-second-order model. The adsorption equilibrium data of ammonium onto the calcium chloride-modified zeolite fitted to the Langmuir isotherm model better than the Freundlich and Dubinin-Radushkevich isotherm models. The phosphate removal efficiency of calcium chloride-modified zeolite increased with the initial concentration of ammonium in aqueous solution. The ammonium removal efficiency of calcium chloride-modified zeolite increased with increasing solution pH from 7.0 to 9.0, but decreased with increasing solution pH from 9.0 to 10.0. The phosphate removal efficiency of calcium chloride-modified zeolite increased dramatically with increasing solution pH from 7.0 to 9.0, but decreased with increasing solution pH from 9.0 to 10.0. The mechanism for the adsorption of ammonium onto the calcium chloride-modified zeolite was ions exchange, and the mechanism for the removal of phosphate by the calcium chloride-modified zeolite was chemical precipitation.

ADCP is convenient for field measurements , But the work of data extraction is heavy , and the flow field distribution map and topographic contour map can’t get from the system software directly , so the rapid extraction of measurement data and mapping technology are two key technologies in river rapid survey by ADCP. This paper studies these two issues , proposed solutions, applied these technologies to the measurement of Nanguotou Permeable Pile Groynes on the Yellow River, and achieved satisfactory results.

The single-layered needle-punched nonwovens and multi-layered needle-punched composite fabrics were prepared in this paper, which were made by polyester fibers under proper parameters. The filtration performance of fabrics was evaluated through the analyses of filtration efficiency, filtration resistance, pore sizes, air permeability and porosity. The mechanical properties of fabrics were also studied. The results show that the filtration efficiency of multi-layered needle-punched composite fabrics increases by about 20% and the filtration resistance drops by about 200% when compared with those of single-layered needle-punched nonwovens. The tensile strength of multi-layered needle-punched composite fabrics goes up obviously. However, the difference between horizontal and vertical strength is visible and the stability is also poor. Compared to the composite fabrics with woven textiles, the composite fabrics with knitted textiles are better in filtration performance, but worse in mechanical properties.

In situ grafting on surface was developed to modify porous microspheres. Functional monomers were grafted onto the porous microspheres. The grafting yield was up to 54.6%. The self-assembly of functional monomer and L-tryptophan molecules was verified by UV spectrometry. The surface imprinted polymer microspheres (SMIPs) were synthesized based on the in situ grafting on surface. The competitive binding experiments were carried out to assess the recognition. The results showed good selectivity of the SMIPs towards target molecule. Langmuir and Freundlich adsorption models were applied to description of the experimental adsorption isotherm. The analysis suggested that the adsorbing behavior of SMIPs was in agreement with Langmuir isotherm equation.

The electronic or pneumatic multi-section and multi-probe gauges are widely used for diameter and coaxiality measurements due to their high measurement efficiency in workshops. However, their measurement accuracy is determined mainly by the manufacturing errors of the assembly coaxiality master, therefore, how to establish coaxiality measurement datum reference is the key technology. The physical coaxiality masters are expected to be the impossible "zero error datum reference". The higher manufacturing accuracy of the masters, the more expensive for their manufacturing costs. A novel mathematical method on the basis of error separation principle was proposed in order to separate the manufacturing errors of the master. The basic principle is that the eccentric error of the coaxiality master can be expressed as the first harmonic function and the ideal zero-error datum reference could be established by the mathematical method of two sampling operations in phase difference of 180° in coaxiality master for gauge initialization. This method can be called as "mathematical datum reference" for coaxiality measurement. Experimental results indicate that the coaxiality measurement results of the multi-section and multi-probe gauge by the novel mathematical method coincide with those of the three-coordinate measuring machine and the maximum difference of both is about 0.0014 mm. The new coaxiality measurement principle can separate the datum error of the coaxiality master theoretically and can improve the coaxiality measurement accuracy greatly with the common accuracy coaxiality master.

In the laboratory condition, a series of experiments were carried out in a sintering pot when Hamersley, Niuman and Hainan lump iron ore were used as sintering hearth layer instead of the recycled sinter. The results show that the sintering productivity is increased by 1.3%, 2.6 % and 13.2 %, and the fuel consumption is decreased by 4.4%, 2.0 % and 6.6 %, respectively. Meanwhile, the tumbler strength and the reduction disintegration index of sinter are also improved. During sintering experiments, the crack of two lump iron ores used as hearth layer didn’t happen. Through using the new technology, the combined water and the sulfur impurity were effectively decreased in the sintering products. Furthermore, the micro-porosity of the sintering products was found to increase, which will contribute to improve the metallurgical properties of sinter.

A case history of a deep multi-strutted soft clay excavation in Hangzhou is presented in this paper. What makes it particular interest is its three characteristics: large scale, deep excavation and very soft clays. The excavated area was about 99750 square meters. The depth of excavation was 12.85 m. 4 m below the ground surface located about 24 m very soft soil clays. Wall deflections and ground settlements were measured and compared with similar case histories worldwide. It was shown that the maximum horizontal deformations of the excavation was very large which this excavation reached to 220 mm. “Creep” deformations occurred apparently during the curing of the bottom slab of the basement. The distributions of the surface settlements seemed to be parabolic, and the settlement influence zone could reach to a distance of more than 2H, whereHis the final excavation depth. The ratio between the maximum ground settlement and the maximum horizontal deformation of the wall is about 0.6.

For the health monitoring of civil structures, the study of finite element model updating or damage detection mainly focuses on undamped systems. Thus, their objective has been exclusively restricted to the correction of the mass and stiffness matrices. In contrast, this paper performs the model updating and damage detection for damped structures. A theoretical contribution of this paper is to extend the cross-model cross-mode (CMCM) method to simultaneously update the mass, damping and stiffness matrices of a finite element model when only few spatially incomplete, complex-valued modes are available. Numerical studies are conducted for a five-story frame structure with multiple damaged elements. The numerical results reveal that applying the CMCM method, together with an iterative Guyan reduction scheme, can yield good damage detection in general.

Nowadays, damping is still the important dynamic characteristic that is the least understood and the most difficult to quantify. The advantage of the proposed damping matrix identification method is that several low order complex modes achieved by Experimental Modal Analysis (EMA) are capable of calculation precision. In order to identify the damping matrix, this paper also proposes a general damping matrix decompositon technique, which can be used in the situation that different parts of the structure have different damping. Then a five-story frame structure is applied to demonstrate the proposed method ,and the results obtained show the suitability of this approach for damping matrix identification in frame structures.

The technology of equipment condition monitoring and diagnosis plays an important role in maintenance of equipment running normally. The project, using advanced technique , etc, realize functions of on-line monitoring and data analysis for it can not only acquire signals on different measuring positions in equipment continuously, but also look over current trend and make primary fault diagnosis. This paper presents a data acquisition and fault diagnosis system of reciprocating compressor using LabVIEW as the software development platform and shows fault recognition by perception neural network. It is proven by experience that the virtual signal analyzer has achieved relatively satisfactory results.