Search

Taking the type of automobile transmission shell as a research object,in order to analyze and judge the performance of an automobile transmission shell,the experimental modal analysis of the automobile transmission shell and finished product is carried out by using the experimental modal analysis technique,comparison the results of extracted the parameter of automobile transmission shell and finished product,the results show that,the automobile transmission shell and the finished product corresponding to each other under 1500 Hz,the modal frequency has a small change in a certain frequency band,the modal damping ratio of the finished product is higher than the auto transmission shell,this provides a revised proposal and an important technical support for the following research of automobile transmission shell.

A new type of high activity EPEG monomer was selected to react with acrylic acid, hydroxyethyl ester and other small monomers. The optimal process for synthesizing anti mud and slump retention polycarboxylate superplasticizer was determined through orthogonal experiment and single factor influence experiments as follows: Acid-ether ratio 2.0, ester-ether ratio 2.6, dropping time material A 40 min, material B 50min, reaction process without temperature control, primer concentration 60%, reducing agent dosage 0.23%, chain transfer agent dosage 0.69%, terminating phosphate ester dosage 4.30%. The test results of cement paste and concrete show that the synthesized polycarboxylate superplasticizer has good dispersibility and slump retention, and has no adverse effect on the strength of concrete. [ABSTRACT FROM AUTHOR]

The design of compact dual‐mode/band filters based on gap waveguide and 3D printing technology is presented in this paper. The spatial power divider is designed to arrange the external coupling. And the multi‐slot middle plate is devised to manage the coupling between the dual‐mode cavities, introducing the non‐resonating modes to produce additional transmission zeros and improving the selectivity. Moreover, the dual‐mode/band filters structure are built up and optimized for 3D printing technology. Finally, the fabricated filters are measured to verify the design. [ABSTRACT FROM AUTHOR]

The rapid development and widespread dissemination of deepfake techniques has caused increased concern. The malicious application of deepfake techniques also poses a potential threat to the society. Therefore, how to detect deepfake content has become a popular research topic. Most of the previous deepfake detection algorithms focused on capturing subtle forgery traces at pixel level and have achieved some results. However, most of the deepfake algorithms ignore the lighting information before and after generation, resulting in some lighting inconsistency between the original face and the forged face, which provided the possibility of using lighting inconsistency to detect deepfake. A corresponding algorithm was designed from two perspectives: introducing lighting inconsistency information and designing a network structure module for a specific task. For the introduction of lighting task, a new network structure was derived by designing the corresponding channel fusion method to provide more lighting inconsistency information to the network feature extraction layer. In order to ensure the portability of the network structure, the process of feature channel fusion was placed before the network extraction information, so that the proposed method can be fully planted to common deepfake detection networks. For the design of the network structure, a deepfake detection method was proposed for lighting inconsistency based on patch-similarity from two perspectives: network structure and loss function design. For the network structure, based on the characteristic of inconsistency between the forged image tampering region and the background region, the extracted features were chunked in the network feature layer and the feature layer similarity matrix was obtained by comparing the patch-wise cosine similarity to make the network focus more on the lighting inconsistency. On this basis, based on the feature layer similarity matching scheme, an independent ground truth and loss function was designed for this task in a targeted manner by comparing the input image with the untampered image of this image for patch-wise authenticity. It is demonstrated experimentally that the accuracy of the proposed method is significantly improved for deepfake detection compared with the baseline method. [ABSTRACT FROM AUTHOR]

Fabrication of segmented cladding fiber (SCF) by bicomponent spinning was proposed in this article. In the new designed spin pack, we considered the high refractive component of cladding and core as a whole to control the cross section of the fiber. Quenching system in current bicomponent melting spinning system was modified according to the requirement of quenching fiber with a large size. The polymer SCF with required cross section was successfully fabricated using polycarbonate and polymethyl methacrylate. The transmission loss in the wavelength of 500-1000 nm was tested by the cut-back method. The result showed that the transmission loss of the obtained fiber was comparatively high, being up to 30 dB/m. The output light pattern of the obtained fiber of 60 cm was collected by using a charge-coupled device camera with laser light of 532 nm as the input. The output light pattern for the far field was a uniform circle and that for the near field was similar to the cross-section designed. The results showed that the obtained fiber was still a multimode optical fiber because of the comparatively large refractive index difference between the two materials used. POLYM. ENG. SCI., 49:1865-1870, 2009. © 2009 Society of Plastics Engineers, INTRODUCTION The effective way to increase the transmission capacity of an optical communication system is by both using the extremely wide bandwidth of an optical fiber and feeding a large [...]