Exploration on the Reform of English Teaching in Universities and Colleges under the Application-oriented Talent Training Mode

With the rapid development of the economy, China’s economic form has also undergone signifcant changes. In this case, the requirements for talents are getting higher and higher. In the process of cultivating talents, schools must constantly change their educational concepts and cultivate more application oriented talents for the society. In this context, the reform of university and college English is of great necessity. Based on the importance of application-oriented talent training, this paper analyzes the current situation of English teaching in universities and colleges under the application-oriented talent training mode, and puts forward some specifc measures for the reform of English teaching in universities and colleges

Image interpolation and denoising in discrete wavelet transform domain

Traditionally, processing a compressed image requires decompression first. Following the related manipulations, the processed image is compressed again for storage. To reduce the computational complexity and processing time, manipulating images in the transform domain, which is possible, is an efficient solution; The uniform wavelet thresholding is one of the most widely used methods for image denoising in the Discrete Wavelet Transform (DWT) domain. This method, however, has the drawback of blurring the edges and the textures of an image after denoising. A new algorithm is proposed in this thesis for image denoising in the DWT domain with no blurring effect. This algorithm uses a suite of feature extraction and image segmentation techniques to construct filter masks for denoising. The novelty of the algorithm is that it directly extracts the edges and texture details of an image from the spatial information contained in the LL subband of DWT domain rather than detecting the edges across multiple scales. An added advantage of this method is the substantial reduction in computational complexity. Experimental results indicate that the new algorithm would yield higher quality images (both qualitatively and quantitatively) than the existing methods; In this thesis, new algorithm for image interpolation in the DWT domain is also discussed. Being different from other methods for interpolation, which focus on Haar wavelet, new interpolation algorithm also investigates other wavelets, such as Daubecuies and Bior. Experimental results indicate that the new algorithm is superior to the traditional methods by comparing the time complexity and quality of the processed image

Strength of flexural members using structural grade 80 of A653 steel (web crippling tests)

This Third Progress Report summarizes the web crippling tests of 148 specimens and evaluates the test results along with an additional 114 web crippling tests which were reported in 1986 as part of a project on Design of Automotive Structural Components Using High-Strength Sheet Steels. The 148 web crippling tests conducted in this program are the part of the overall project on Strength of Flexural Members Using the Structural Grade 80 of ASTM A653 Steel (former ASTM A446 Grade E Steel). The objectives of the ongoing project are to study the strength and structural performance of flexural members as affected by using the high-strength, low-ductility Structural Grade 80 Steel and to develop appropriate design criteria based on the test programs. Four loading conditions, namely End-One-Flange (EOF), Interior-One-Flange (IOF), End-Two-Flange (ETF), and Interior-Two-Flange (lTF) conditions, were considered in the web crippling tests in this program and in those reported in 1986. The web crippling test program for this study included 136 single-rib and double-rib specimens having a hat-shaped section and sloped webs and 12 single-rib specimens having a hat-shaped section and vertical webs. The previous 114 specimens reported in 1986 had a single-rib hat-shaped section with vertical webs. For the specimens tested in this program, the yield strength of the steel ranged from 103.9 to 112.5 ksi, h/t ratio from 25.99 to 208.19, R/t ratio from 2.16 to 5.51, N/t ratio from 34.48 to 88.24, N/h ratio from 0.22 to 2.02, thickness of steel sheet ranged from 0.017 to 0.029 inches, and the angle between the plane of the web and the plane of bearing surface ranged from 59.5 to 90 degrees. All specimens were loaded to failure. Both the web crippling tests in this program and those reported in 1986 indicated that the tested ultimate loads for the four loading conditions were higher than the predicted loads using the AISI Specification, and modified kC1 and kC3 factors (1.691 for kC1 when Fy exceeds 91.5 ksi and 1.34 for kC3 when Fy exceeds 66.5 ksi), for the yield strength of the steels exceeding 80 ksi. The ratio of the tested ultimate load to the calculated load tends to increase with increase in the yield strength of the steels beyond 80 ksi. Therefore, it is conservative to use the kC1 and kC3 factors in Section 3.4 of the current AISI Specification for predicting web crippling strength of structural members with yield strength exceeding 80 ksi. It appears that the low ductility of the Structural Grade 80 steel does not reduce the web crippling strength of the members made of such steels. As a result, new modified kC1 and kC3 factors were developed based on the 262 web crippling tests which included the following parameters: the yield strength Fy ranged from 58.2 ksi to 165.1 ksi, h/t ratio from 25.99 to 208.19, R/t ratio from 1.496 to 5.696, N/t ratio from 22.70 to 88.24, N/h ratio from 0.17 to 2.02, thickness of steel sheets ranged from 0.017 in. to 0.088 in., and the angle between the plane of the web and the plane of bearing surface ranged from 59.5 to 90 degrees. Reasonable agreement was found between the tested ultimate loads and the predicted loads using the newly modified kC1 and kC3 factors. It is also recommended that in order to simplify designs, the current kC1 in Section 3.4 of the AISI Specification can be used for all the IOF, ITF, EOF, and ETF loading conditions, resulting in a simple but conservative solution

Design of automotive structural components using high strength sheet steels mechanical properties of materials (aging effect)

INTRODUCTION It has been known for years that mechanical properties of thin sheet steels, such as yield strength, tensile strength, and ductility, are affected by aging (Chajes et al. 1963, Hertzberg 1989, Yu 1991). The aging effect on mechanical properties can be described as follows. For a virgin steel that is initially loaded in tension beyond its yield strength and into strain hardening state and then unloaded to zero stress, the yield and tensile strengths of the steel increase while the ductility of the steel decreases if the steel is reloaded in tension again after a period of time from the first unloading. Due to diffusion of the carbon and nitrogen in steels and the fact that steel sheets are usually produced in a cold rolling process, in which the sheet steels undergo large plastic deformation, their mechanical properties can be affected by aging. Therefore, the mechanical properties of the thin sheet steels at the time when they are used can be different from the properties at the time when they are produced. The yield and tensile strengths of the sheet steels will increase over time while the ductility of the steels will decrease. In 1992, a research project, sponsored by the American Iron and Steel Institute (AISI), was carried out at the University of Missouri-Rolla to study the effect of strain rate on the mechanical properties of sheet steels (Pan and Yu 1992). In this research, coupons cut from two selected sheet steels (25AK and 50SK) were tested in longitudinal and transverse tension and compression at four different strain rates, namely 0.0001,0.01,0.1, and 1.0 in./in./sec.. The results of the study were reported by Pan and Yu (1992). Later on for another study on the strength of hybrid structural components made of these two steels (Pan and Yu 1995), the mechanical properties of the steels that were obtained in 1992 were used to evaluate the strength of the hybrid members without consideration of the aging effect. In this later study, the hybrid members were tested in bending at the strain rates of 0.0001 and 0.01 in./in./sec.. In order to estimate the aging effect on the mechanical properties of two types of sheet steels used by Pan and Yu (1992), additional coupon tests of the sheet steels (25AK and 50SK) were conducted at the University of Missouri-Rolla in August 1995 and in January 1997. A total of twenty coupons, ten for each steel, were tested at two different strain rates, namely 0.0001 and 0.01 in./in./sec.. Four coupons for each steel were tested at the strain rate of 0.0001 in./in./sec. in August 1995, while three coupons for each steel were tested at the strain rate of 0.0001 in./in./sec. in January 1997 and another three coupons for each steel were tested at the strain rate of 0.01 in./in./sec. at the same time. This report summarizes the results of the twenty coupon tests. In the following discussions, Section 2 presents the test results on the mechanical properties of25AK and 50SK sheet steels. Section 3 compares the mechanical properties of the steels reported by Pan and Yu (1992) with those presented in Section 2 to estimate the aging effect on steels and the computed yield moments. Finally, Section 4 summarizes the findings

A Low Complexity Navigation Data Estimation Algorithm for Weak GNSS Signal Tracking

The computation load of traditional navigation data estimation algorithms for weak GNSS signal tracking increases exponentially with respect to the number of data bits needed to be estimated. To solve this problem, by adopting the dynamic programming philosophy, a navigation data bits estimation algorithm is proposed. The proposed algorithm uses the partial sum of correlation values as data bit combination searching branches. It can predict and exclude searching branches of data bit combination which have small coherent accumulated energy as soon as possible by angle quantification, thus reducing its computation load to be linearly related to the number of data bits needed to be estimated. Simulation results show that for signal of 500bps navigation data rate, the carrier track loop with a frequency discriminator implementing 0.12s coherent accumulation by navigation data estimation improves the tracking sensitivity up to 7 dB compared with traditional frequency discriminator under the same track accuracy constraint

Web Crippling Strength of Members Using High-strength Steels

A total of 148 web crippling tests were conducted using high-strength, low-ductility Structural Grade 80 of ASTM A653 steel (former ASTM A446 Grade E steel) and tests results were evaluated along with additional 114 web crippling tests which were reported in 1986 as part of a project on Design of Automotive Structural Components Using High-Strength Sheet Steels. Four loading conditions, namely End-One-Flange (EOF),lnterior-One-Flange (IOF), End-Two-Flange (ETF), and Interior-Two-Flange (ITF) conditions, were considered in the web crippling tests. Test results indicate that the tested ultimate loads for the four loading conditions were higher than the predicted loads using the AISI Specifications for the yield strength of the steels exceeding 80 ksi (551.6 MPa). The ratio of the tested ultimate load to the calculated load tends to increase with increase in the yield strength of the steels beyond 80 ksi. New modified kC₠and kC₃, factors were developed based on the 262 web crippling tests which included the following parameters: the yield strength Fy ranged from 58.2 ksi (401.3 MPa) to 165.1 ksi (1138.4 MPa), h/t ratio from 25.99 to 208.19, R/t ratio from 1.496 to 5.696, N/t ratio from 22.70 to 88.24, N/h ratio from 0.17 to 2.02, thickness of steel sheets from 0.017 to 0.088 (0.43 to 2.24 mm), and the angle between plane of web and plane of bearing surface from 59.5 to 90 degree. Reasonable agreement was found between the tested ultimate loads and the predicted loads using the new modified kC₠and kC₃, factors

Strength of flexural members using structural grade 80 of A653 steel (deck panel tests)

This second progress report describes the design of deck panel specimens for flexural tests and presents the test results of ninety-three deck panel specimens. The deck panels consisted of single and multiple hat-shaped ribs in their cross sections and were manufactured from 28, 26, and 22 gage steel sheets of Structural Grade 80 of ASTM A653 Steel. Among the ninety-three deck panel specimens, seventy-two panels were tested in simply supported and two-point loading conditions; sixteen panels were tested in simply supported and one-point loading conditions; and five panels with screws penetrating through tension flanges were tested in simply supported and two-point loading conditions. Three yielding conditions were considered in the design of the deck panel specimens, namely first yielding occurring in compression flange only, first yielding occurring in both compression and tension flanges simultaneously, and first yielding occurring in tension flange only. The specimens and the test setup were designed to ensure only a flexural failure mode. The actual average w/t ratio of the specimens ranged from 17.93 to 189.95 and the actual average h/t ratio ranged from 17.67 to 104.43. The actual average angle between planes of the web and bearing surface varied from 59.06 to 62.21 degree. The actual average yield strength of the sheet steels varied from 103.9 to 112.5 ksi. For the two-point loading condition, the test results indicated that for the panel specimens with small w/t ratios (17.93 to 61.07), the tested yield moments were reached and compared reasonably well with the calculated effective yield moments using actual dimensions, actual yield strength of the steel, and the 1986 AISI Specification. However, for the panel specimens with large w/t ratios (102.86 to 189.95), the tested ultimate moments were lower than the calculated effective yield moments using actual yield strength of the steel, but much larger than the calculated moments using the 75% of the specified minimum yield strength of the steel (that is 60 ksi), and even larger than the calculated moments using 100% of the specified minimum yield strength of the steel (80 ksi). Panel specimens designed for the first yielding in the tension flange developed higher ratios of tested yield moment to calculated effective yield moment. Higher tested yield moment to weight-per-Iength ratio of the panel was achieved for specimens designed for the first yielding in both compression and tension flanges simultaneously. For the one-point loading condition, the test results indicated that for all sixteen panels, the ratios of the tested yield moment to the calculated effective yield moment using actual yield strength of the steel and the ratios of the tested ultimate moment to the calculated effective yield moment followed the similar trend with respect to the w/t ratio as the panels tested in two-point loading condition. In addition, for the one-point loading condition, the panels with small w/t ratios (17.93 to 31.65) developed higher ratios of the tested yield moment to the calculated effective yield moment and higher ratios of the tested ultimate moment to the calculated effective yield moment, but demonstrated less overall ductility in the load-displacement relationship as compared to the panels with the two-point loading condition. The panels with large w/t ratios (118.64 to 189.95) developed only slightly higher ratios of the tested ultimate moment to the calculated effective yield moment as compared to the panels with the two-point loading condition. For the deck panels with screws penetrating through tension flanges, it was found that the ultimate tested moment and displacement of the panels with screws were nearly equal to those of the panels without screws. Only one 22 gage panel with 27% of reduction in tension flange and designed for first yielding in tension flange experienced tensile fracture and necking near the holes after the panel entered a plateau in its load-displacement curve. The test results also showed that for almost all the deck panels with either a two-point or a one-point loading condition, the tested central displacements were near or less than the calculated central displacements using effective moment of inertia at service load, actual dimensions, and modulus of elasticity of 29,500 ksi. Fracture in tension was not observed in the tested panels without screws. The flexural strength of the panels was more strongly affected by the w/t ratios of the panels and did not appear to be influenced by the low-ductility and low Fu/Fy ratio of the steel for the panels with small w/t ratios. It is concluded that the current design practice for designing cold-formed flexural members using 75% of the specified minimum yield strength of the Structural Grade 80 of ASTM A653 steel or 60 ksi (whichever is less) is conservative, especially for the members with small w/t ratios (less than 60). A modified yield strength reduction factor was developed to be used for determining the flexural strength of the panels with yield strength between 80 ksi and 150 ksi (including 80 and 150 ksi) and w/t ratio not exceeding 190. For panels with (w/t)(Fy/E) ratio of 1/15 or less, the actual yield strength of steels can be used for determining the flexural strength of the panels. Reasonable agreements are achieved between tested moments and predicted moments using the modified yield strength reduction factor

Flexural Strength of Cold-formed Steel Panels Using Structural Grade 80 of A653 Steel

Cold-formed steel decks made of the Structural Grade 80 of ASTM A653 steel (formerly ASTM A446 Grade E steel) are currently designed according to the AlSI specification, using 75% of the specified minimum yield strength of the steel or 60 ksi (413.7 MPa), whichever is less, due to the lack of ductility of the steel. To further evaluate the flexural strength of the cold-formed steel decks using such a steel, a total of seventy-two deck panels with hat-shaped sections were designed and tested under simply supported and two-point loading condition. The test results indicated that for the panel specimens with small w/t ratios (17.93 to 61.07), the tested yield moments were reached and are compared reasonably well with the calculated effective yield moments using actual dimensions, actual yield strength of the steel, and the 1986 AlSI Specification. However, for the panel specimens with large w/t ratios (102.86 to 189.95), the tested ultimate moments are lower than the calculated effective yield moments, but much larger than the calculated moments using the specified value of 60 ksi. Fracture in tension was not observed in the tested panels. Panel specimens designed for the first yielding in the tension flange developed higher ratios of tested yield moment to calculated effective yield moment