Search

The present paper focused on both turbulent flow and laminar flow at low Reynolds number in a curved duct. The finite volume method on unstructured grid and SIMPLEC algorithm were adopted here and the computation program was design with these methods. Good agreement was achieved between the numerical result and experimental data in the literature, and it shows that the method is reasonable and the program works well. The numerical method was also used to flow simulation with different attack angle and side angle, and numerical results were consistent with conclusion in the literature. Finally, the numerical method used for cases with different Reynolds number at the inlet. Secondary flow phenomena have been researched in the curved duct and some conclusions were derived.

The self-inductance is the inherent phenomenon in a wire. Through the comparison of two kinds of method for solving the self-inductance, stated that note in the current contribution rate problem in the process by the first method to solve the self-inductance coefficient. Through solving the relationship between the coefficient of self-inductance and cable radial thickness for coaxial cables that cable, the coefficient of self-inductance decreases monotonously with the radial thickness of the reduction.

Corrugated box, as a kind of packaging product in the paper packing industry, fulfills the requirements on China’s circular economy development, and has become one of the most widely adopted containers for modern packing. The analysis of corrugated box has shown that the main affection of corrugated box were respiratory inorganics, climate change and acidification/eutrophication. The critical point has been found in respiratory inorganics which normalization result is 50.64, and the impact categories showed climate change was 898793.5 kg CO2-eq in the system. The serious life cycle stages were the manufacture of base paper and cardboard/corrugated box.

The installation position of nozzle directly affect the efficiency of high pressure water jet cleaning. In order to improve the cleaning efficiency, the paper establish the three-dimensional structure and numerical model of the original nozzle assembly and the spiral nozzle assembly. The numerical simulation results show that, on the same boundary conditions, the effective hit range of the spiral nozzle assembly is greater and more uniform than that of the original nozzle assembly.The effective surge pressure of the spiral nozzle assembly is larger than that of the original nozzle assembly, spiral nozzle assembly can can reduce the blind cleaning area and improve the cleaning efficiency.

Oxygen plasma was utilized to etch the epitaxial graphene films grown on carbon-terminated 6H-SiC substrate. XPS spectra show that the intensity ratio between the graphene peak and SiC peak decreases with oxygen plasma etching time. It indicates that with increasing etching time from 0 to 42 s, the thickness of graphene dramatically decreases from eight to one monolayers following a first-order exponential decay function. Meanwhile, AFM images show that the ridges among domains are preferred to be etched by oxygen plasma and they will almost disappear after etched for 42 s. It indicates that the oxygen plasma will not decrease the mobility of graphene layer obviously when the graphene thickness is over two monolayers; however, further etching the graphene with thickness less than two monolayers will leads to significantly decrease the mobility due to the formation of many more defects.

Choosing Features of a text is an important part of text categorization. Its result can affect the quality and efficiency of the text categorizer. Since there are usually thousands of features of a text, it always needs to reduce the dimension of the feature space. Considering the semantic relationship among words, a new text categorization method based on features clustering is proposed in this paper. This method first uses word segmentation to split texts into words, then, remove stop words and words with low information, and then calculate the distribution of words in these texts to construct a matrix of co-occurrence words. After that, cluster algorithms are employed to reduce the dimension of the feature space. Finally some experiments are carried out on two corpuses using several text categorization algorithms. The results demonstrate that this new method can not only improve the precision and recall of text categorization, but also increase the efficiency.

This paper is mainly about improving vehicle use friction material and reducing vehicle braking noise. With the improvement of friction sheet material prescription as breakthrough point, we aim at raising the friction performance and high temperature capability, so that we can reduce the friction of mating plate efficiently and reduce brake noise. In this experiment combinatorial friction materials research is conducted. Raw materials used are screened by two criteria:1、 select those raw materials which have good wear resistance when they combine with group raw materials; 2、 select those raw materials that have the function of reducing brake noise。 Golden Section approach is utilized for experimental formulations design. Comprehensive index of raw materials is obtained by the relational grade analysis. The fuzzy overall merits method is utilized to judge comprehensive index and evaluates merits of multi-objective friction material formulations, so that we can determine one friction material formulation with the best friction performance. Using fixed-velocity D-MS friction experiment machine we test the crucial property for the autonomous new brake friction material. Test content includes mainly: hot decline, wear rate, blow energy and the friction coefficient of test piece in different experiment temperatures. On fixed-velocity friction experiment machine, we adopt advanced friction vibration and noise experiment methods, use HY104A model of the ordinary sound level analyzer to test in some fixed points, and take autonomous strengthened new brake friction material for object. We analyze and study brake noise that some kinds of friction flats produces. Through observing and analyzing the property of friction material and experiment phenomenon and data, we discover the strong weak level of noise has close relation with friction material formulation and the composition of material. Eventually we can decide the best formulation to degrade the brake nose. Brake friction material is a crucial factor to influence vehicle traveling safety. Through the research of this program we can offer some reference about how to select reasonable friction material group and improve the property of friction flats.

Digital technology means the data processing, transfer of information, intelligent control and many other multi-dimensional technologies that on the basis of computer technology. It will not only make the building more automatic, more efficient and more intelligentized, but also have a all-sided influence to the traditional architecture through the computer technology and net technology. In the area of architecture design, including the traditional thinking, method, craftsmanship and the constitution of architectural space and form, are also changing and developing in order to advancing with the times. This document is base on the nucleus of architecture design, put forward some consideration about design idea as well as research method of architecture in digital age and the trend and possibility of the architecture development under the action of digitization technic.