Mobile Communication Voice Enhancement Under Convolutional Neural Networks and the Internet of Things

This study aims to reduce the interference of ambient noise in mobile communication,improve the accuracy and authenticity of information transmitted by sound,and guarantee the accuracy of voice information deliv-ered by mobile communication.First,the principles and techniques of speech enhancement are analyzed,and a fast lateral recursive least square method(FLRLS method)is adopted to process sound data.Then,the convolutional neural networks(CNNs)-based noise recognition CNN(NR-CNN)algorithm and speech enhancement model are proposed.Finally,related experiments are designed to verify the performance of the proposed algorithm and model.The experimental results show that the noise classification accuracy of the NR-CNN noise recognition algorithm is higher than 99.82%,and the recall rate and F1 value are also higher than 99.92.The proposed sound enhance-ment model can effectively enhance the original sound in the case of noise interference.After the CNN is incorporated,the average value of all noisy sound perception quality evaluation system values is improved by over 21%compared with that of the traditional noise reduction method.The proposed algorithm can adapt to a variety of voice environments and can simultaneously enhance and reduce noise processing on a variety of different types of voice signals,and the processing effect is better than that of traditional sound enhancement models.In addition,the sound distortion index of the proposed speech enhancement model is inferior to that of the control group,indicating that the addition of the CNN neural network is less likely to cause sound signal distortion in various sound environments and shows superior robustness.In summary,the proposed CNN-based speech enhancement model shows significant sound enhancement effects,stable performance,and strong adapt-ability.This study provides a reference and basis for research applying neural networks in speech enhancement.

Synergetic photo-epoxidation of propylene with molecular oxygen over bimetallic Au–Ag/TS-1 photocatalysts

Au-Ag bimetallic nanoparticle‐supported microporous titanium silicalite‐1catalysts were prepared via a hydrothermal‐immersion method,and their structures were examined.These materials serve as efficient catalysts for the photosynthesis of propylene oxide via the epoxidation of propene.The Au/Ag mass ratio and reaction temperature were demonstrated to have significant effects on the catalytic activity and selectivity of propylene oxide.The optimal formation rate(68.3μmol/g·h)and selectivity(52.3%)toward propylene oxide were achieved with an Au:Ag mass ratio of4:1.Notably,the strong synergistic effect between Au and Ag resulted in superior photocatalysis of the bimetallic systems compared with those of the individual systems.A probable reaction mechanism was proposed based on the theoretical and experimental results.

Novel Perchlorate and Sulphate Salts of 2-Aminonicotinic Acid:Synthesis,Characterization,Thermal Studies and Hirshfeld Surface Analysis

Since 2-aminonicotinic acid is a zwitterionic molecule,the salt or co-crystal strategy was used for the precipitation under identical conditions and obtained two novel salts： salt 1 with 2：1：2 stoichiometry of 2-aminonicotinic acid：perchloric acid：H2O and salt 2 with 2：1：3 stoichiometry of 2-aminonicotinic acid：sulfuric acid：H2O. Their crystal structures were characterized by single-crystal X-ray diffraction,differential scanning calorimetry（DSC） and thermogravimetric analyses（TGA）. The structure determination shows that two salts are both primarily stabilized by the strong N–H…O hydrogen bonding interaction between 2-aminonicotinic acid and its corresponding acids. Constituents of the salt-crystalline phase were also investigated in terms of Hirshfeld surfaces. In the crystal lattice,a three-dimensional hydrogen-bonded network is observed,including the formation of a two-dimensional molecular scaffolding motif. Hirshfeld surfaces and fingerprint plots of two salts show that the structures are stabilized by H…H,O–H…O and C–O…π intermolecular interactions.

Synthesis and Density Functional Theory(DFT) Calculation of Haptens for PAHs

Five PAHs haptens 3 a～3 e were synthesized from naphthalene, anthracene, chrysene, pyrene and acenaphthene via two steps including Friedel-Crafts acylation and WolffKishner-Huang reduction. The sixth hapten 4-(acenaphthylen-3-yl)butanoic acid(3 f) was prepared from hapten 3 e via three steps including esterification, bromination and elimination. Their structures were confirmed by melting point, ~1H NMR and ^(13)C NMR. Their optical properties and crystal structures were also investigated. The results of density functional theory(DFT) calculation provided the supports that the size, shape(geometry) and electronic properties at the corresponding parts of 3 a～3 f did not change significantly, compared to those of PAHs. The haptens 3 a～3 f were coupled with bovine serum albumin(BSA) to make antigens. The coupling ratios were 1:20～1:38. These results show that the haptens could be used to induce specific antibodies for PAHs.

Comparison of Fungicidal Difference of Two Arylpyrazoles Based on the Crystal Structures, Density Functional Theory Calculation and Molecular Docking

Two arylpyrazoles I andⅡwere synthesized and characterized by NMR and single-crystal X-ray diffraction.Compound I displayed 71.4%fungicidal inhibition rate against Rhizoctonia solani at 0.1 ppm,better than the control pyraclostrobin,whereasⅡhad little activity.Their fungicidal difference was discussed from theoretic level based on the crystal structure,density functional theory(DFT)calculation and molecular docking.The B3 LYP/6-31G^**level was employed to explore the HOMO-LUMO energy gap and charge distribution.Molecular docking was performed on the probable target protein bc1-enzyme complex.DFT calculation and docking studies supported the in vitro findings.

Intercultural study of euphemisms in Chinese and English

Language and culture are closely related to each other. Euphemisms, which exist in all languages, reflect certain culture from which the language derives. Paying special attention to cross cultural communication, this paper discusses the relationship between euphemism and culture. Pointing out the necessity of learning and teaching euphemisms, the author also proposes some suggestions on how to teach euphemism.

Practice Teaching Reform of Mechanical Design and Manufacture and Its Automation Specialty under Transformation and Development

With the development of the times, undergraduate colleges and universities begin to transform and develop to adapt to the changing society, and put forward new requirements for practical teaching strategies, especially for applied undergraduate colleges. The reform of practical teaching is particularly important. Under the development of education transformation, the reform of mechanical design and manufacture and the practice teaching of automation specialty also occupy a very important position. Through the understanding of the reform of the practical teaching of this specialty, the effect of the reform is observed, and a reasonable teaching scheme is put forward to promote the steps of the transformation of the practical teaching.

Cultural Relevance of Color Terms in Chinese and English

Color terms perform both the aesthetic and informative functions and possess various meanings according to different cultural backgrounds. It seems that people are more likely to label colors in a consistent fashion in each unique culture. Therefore, it is highly essential to investigate the cultural relevance of color terms, especially the color words in Chinese and English. Translation of color terms is also discussed from different aspects to show people's cultural preferences.

Used car price prediction based on XGBoost and retention rate

In order to improve the accuracy of used car price prediction,a machine learning prediction model based on the retention rate is proposed in this paper.Firstly,a random forest algorithm is used to filter the variables in the data.Seven main characteristic variables that affect used car prices,such as new car price,service time,mileage and so on,are filtered out.Then,the linear regression classification method is introduced to classify the test data into high and low retention rate data.After that,the extreme gradient boosting(XGBoost)regression model is built for the two datasets respectively.The prediction results show that the comprehensive evaluation index of the proposed model is 0.548,which is significantly improved compared to 0.488 of the original XGBoost model.Finally,compared with other representative machine learning algorithms,this model shows certain advantages in terms of mean absolute percentage error(MAPE),5%accuracy rate and comprehensive evaluation index.As a result,the retention rate-based machine learning model established in this paper has significant advantages in terms of the accuracy of used car price prediction.

Facile Synthesis of Cellulose Acetate Ultrafiltration Membrane with Stimuli-Responsiveness to pH and Temperature Using the Additive of F127-b-PDMAEMA

We fabricate a novel cellulose acetate （CA） ultrafiltration membrane modified by block copolymer F127-b- PDMAEMA, which is synthesized using F127 and DMAEMA via the ARGET ATRP method. Compared to conven- tional ultrafiltration membranes, the incorporation of both F 127 and PDMAEMA can not only readily increase the hydrophilicity of the membrane, but also exhibit stimuli-responsiveness to temperature and pH. Fourier transform infrared spectroscopy （FT-IR）, nuclear magnetic resonance spectroscopy （NMR）, and gel permeation chromatog- raphy （GPC） are employed to analyze the structure of the F 127-b-PDMAEMA. The membrane properties are eval- uated via scanning electron microscope （SEM） imaging, porosity test, automatic target recognition Fourier trans- form infrared spectroscopy （ATR-FTIR）, water contact angle test and permeation test. The results indicate that the F 127-b-PDMAEMA is an excellent pore agent, which contributes to an enhancement of the membrane in sensitivity to temperature and pH. The modified membrane also exhibits lower water contact angle （64.5~）, which is attributed to the good anti-fouling performance and high water permeation.

Fabrication of a superamphiphobic coating by a simple and flexible method

A facile and flexible method to prepare raspberry-like nanoparticles that can be used as a superamphipho- bic coating is reported. Anatase TiO2 nanoparticles were chosen as the core because of their irregular morphology and photocatalytic performance. Anatase TiO2 nanoparticles were surrounded tightly by tiny functional fluoride-silica nanoparticles via the hydrolysis-condensation reaction of tetraethoxysi- lane and IH, 1H, 2H, 2H-perfluorodecyl triethoxysilane. The obtained Si-F@TiO2 nanoparticles can be sprayed or dipped directly onto various substrates. The coated film exhibited quite good liquid resistance, even when subjected to water jetting and sand abrasion. The photocatalytic effect of the coated anatase TiO2 with respect to formaldehyde was also studied and discussed. This method will provide more opportunities and fast access to practical applications in surface, environmental, and energy engineering.

QCD equation of state for heavy ion collisions

In this work, we calculate the equation of state（EoS） of quark gluon-plasma（QGP） using the CornwallJackiw-Tomboulis（CJT） effective action. We get the quark propagator by using the rank-1 separable model within the framework of the Dyson-Schwinger equations（DSEs）. The results from CJT effective action are compared with lattice QCD data. We find that, when μ is small, our results generally fit the lattice QCD data when T〉T_c,but show deviations at and below T_c. It can be concluded that the EoS of CJT is reliable when T〉T_c. Then,by adopting the hydrodynamic code UVH2＋1, we compare the CJT results of the multiplicity and elliptic flow v2 with the PHENIX data and the results from the original EoS in UVH2＋1. While the CJT results of multiplicities generally match the original UVH2＋1 results and fit the experimental data, the CJT results of v2 are slightly larger than the original UVH2＋1 results for centralities smaller than 40% and smaller than the original UVH2＋1 results for higher centralities.