In the context of the continuous improvement of chip interconnection density and the further development of high-frequency communication, in order to better realize high frequency signal transmission, the interlayer dielectric insulating material between the chip interconnection layers needs to have a lower dielectric constant, so as to effectively avoid undesirable phenomena such as signal delay and crosstalk. The metal of the interconnection layer is mainly copper in the current chip Damascus Copper Interconnect Process, so it is not only limited to the preparation of insulating high performance films on the silicon surface, but also of great significance to prepare insulating films with low dielectric properties on copper. Researches have shown that the addition of polyhedral oligomeric silsesquioxane (POSS) to the polymer can make the material with higher thermal stability and mechanical toughness. Due to their desirable properties, POSS-containing polymers are expected to be further developed into high-performance electronic materials, such as interlayer dielectric materials with low-k dielectric properties. But POSS has also a major difficulty in application because of its insolubility in aqueous solution. In this experiment, we successfully covalently graft organic insulating films with POSS nanostructures on the surface of copper in an atmospheric environment by using the electrochemical grafting technology based on aryldiazonium salts. In the experiment, tetrahydrofuran and deionized water are used as mixed solvent, 4-Nitrobenzenediazonium tetrafluoroborate (NBD) as initiator, octavinylsilsesquioxane (OVS) as monomer, sodium dodecyl sulfonate (SDS) as surfactant and sulphuric acid (H2SO4) as acid regulating reagent to make the pH of the mixed solution less than 2. The initiator NBD receives the electrons provided by the cathode of the pulse power supply and reduces to nitrobenzene radical. The nitrobenzene radical further initiates the polymerization of OVS with vinyl groups, and then grows a film with POSS nano pores on the copper substrate. By means of micro infrared spectroscopy (IR), X-ray spectrometer (XPS), ellipsometer and atomic force microscope (AFM), it is further determined that the composition of the film is mainly the mixed structure of polynitrophenyl (PNP) and POSS. In addition, the content and dielectric constant of POSS in the film can be adjusted by adjusting the concentration ratio of initiator NBD and monomer OVS. The obtained insulating film has chemical bond connected with the substrate, and the film has good hydrophobic, dielectric and mechanical properties. Its dielectric constant is lower than that of traditional low k materials and some recently reported materials. This insulating film has good dielectric properties and comprehensive properties, which also means that it has potential commercial application value in the field of higher frequency communication such as 6G communication in the future.
Aiming at the problem of low fault diagnosis rate of planetary gearbox caused by insufficient fault data in actual industry, a method was proposed based on dynamic adversarial network. The domain-shared one dimensional feature extraction network was first built from the fault data. Secondly, the global discriminator and subdomain discriminator was used to align adaptively the distribution of fault features, and the weight index was used to evaluate the relative weight of those discriminators. Then, the joint loss of weight index, discriminator loss and classification loss is used as the objective function for training. Finally, the trained model was used to identify the target domain health conditions. The experimental results show that the proposed dynamic adversarial network may achieve better accuracy in a small amount of fault data.
A novel and efficient method for the generation of o-quinone methide intermediates was developed from the readily available 2-tosylalkylphenols under the mild basic conditions, and their reactions with sulfur ylides were investigated for the stereoselective synthesis of trans-2,3-dihydrobenzofurans.
Polyrhachis dives is a traditional edible insect with high nutritional value and is the only ant species that is administered as medicine and food. Therefore, it is of great significance to identify its source. In the current study, a method combining untargeted MS with targeted MS was developed and applied for the identification of specific biomarkers in Chinese black ants and the establishment of quality standards. A total of 16 specific peptide sequences were screened, yielding a total of 8 specific peptide biomarkers with satisfactory signal response via targeted MS analysis. Additionally, these peptides were quantitatively analyzed, revealing that they can be used to distinguish Chinese black ants from other ant species and to ensure the quality of edible ants.
In order to obtain the exact time delay of pulses in the surface acoustic wave (SAW) based radio frequency identification (RFID) at unknown temperature, we propose a method for obtaining a high phase ambiguity resolution by measuring group delays and constructing some restriction on the exact positions of reflectors. To define the restriction parameters for a SAW RFID system with large code capacity and reliable identification, it is imperative to have a priori knowledge on the errors of group delay and phase. In this paper, we present the experimental and simulation errors for both phases and group delay, originated from the design procedure, the temperature effect, the fabrication process and the measurement. The temperature range in our investigation is -5deg -45degC. The average error of phase delay is about 4deg; the maximum error of phase delay is about 16deg. The maximum error of group delay is about 10 periods.
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