一个R2上含双曲函数核的Hilbert型不等式

通过引入参数，构造了一个全平面上的、含双曲函数的非齐次核函数。利用正切函数的有理分式展开，建立了最佳常数因子与正切函数高阶导数相关联的Hilbert型积分不等式。 作为应用，通过赋予参数不同的值，建立了一些有意义的特殊结果。     

Effect of aromatic substitution on the cure reaction and network properties of anhydride cured triphenyl ether tetraglycidyl epoxy resins

A systemic study of the impact of aromatic substitution on the reaction rate and network properties of the isomers of a tetraglycidylaniline triphenyl ether epoxy resin cured with anhydride hardeners is presented here. The epoxy resins synthesized in this work were based upon N,N,N,N‐tetraglycidyl bis(aminophenoxy)benzene (TGAPB), where the glycidyl aniline and ether groups change from being all meta (133 TGAPB), to meta and para (134 TGAPB), and finally to an all para substituted epoxy resin (144 TGAPB). Increasing para substitution increased reaction rate, promoted the onset of vitrification and increased epoxide conversion. Thermal properties such as glass transition temperatures (T_g) and coefficients of thermal expansion (CTE) both increased consistently with increasing para substitution, although thermal stability as measured via thermogravimetric analysis decreased. Mechanical properties also varied systematically with flexural strength and ductility increasing with increased para substitution, while the modulus decreased. Indeed, the ductility almost doubled, as measured by the work of fracture and displacement at failure highlighting the importance of substitution on properties.     

Adaptive Neuro-Fuzzy Inference System and a Multilayer Perceptron Model Trained with Grey Wolf Optimizer for Predicting Solar Diffuse Fraction

The accurate prediction of the solar diffuse fraction (DF), sometimes called the diffuse ratio, is an important topic for solar energy research. In the present study, the current state of Diffuse irradiance research is discussed and then three robust, machine learning (ML) models are examined using a large dataset (almost eight years) of hourly readings from Almeria, Spain. The ML models used herein, are a hybrid adaptive network-based fuzzy inference system (ANFIS), a single multi-layer perceptron (MLP) and a hybrid multi-layer perceptron grey wolf optimizer (MLP-GWO). These models were evaluated for their predictive precision, using various solar and DF irradiance data, from Spain. The results were then evaluated using frequently used evaluation criteria, the mean absolute error (MAE), mean error (ME) and the root mean square error (RMSE). The results showed that the MLP-GWO model, followed by the ANFIS model, provided a higher performance in both the training and the testing procedures.     

Interfacial area concentration in gas–liquid bubbly to churn flow regimes in large diameter pipes

This study performed a survey on existing correlations for interfacial area concentration (IAC) prediction and collected an IAC experimental database of two-phase flows taken under various flow conditions in large diameter pipes. Although some of these existing correlations were developed by partly using the IAC databases taken in the low-void-fraction two-phase flows in large diameter pipes, no correlation can satisfactorily predict the IAC in the two-phase flows changing from bubbly, cap bubbly to churn flow in the collected database of large diameter pipes. So this study presented a systematic way to predict the IAC for the bubbly-to-churn flows in large diameter pipes by categorizing bubbles into two groups (group 1: spherical or distorted bubble, group 2: cap bubble). A correlation was developed to predict the group 1 void fraction by using the void fraction for all bubble. The group 1 bubble IAC and bubble diameter were modeled by using the key parameters such as group 1 void fraction and bubble Reynolds number based on the analysis of Hibiki and Ishii (2001, 2002) using one-dimensional bubble number density and interfacial area transport equations. The correlations of IAC and bubble diameter for group 2 cap bubbles were developed by taking into account the characteristics of the representative bubbles among the group 2 bubbles and the comparison between a newly-derived drift velocity correlation for large diameter pipes and the existing drift velocity correlation of Kataoka and Ishii (1987) for large diameter pipes. The predictions from the newly-developed two-group IAC correlation were compared with the collected experimental data in gas–liquid bubbly to churn flow regimes in large diameter pipes and their mean absolute relative deviations were obtained to be 28.1%, 54.4% and 29.6% for group 1, group 2 and all bubbles respectively.     

Belle实验发现新超子和新粲重子

过去一年里,运行在日本高能加速器研究机构的Belle实验在重子研究,尤其是在超子和粲重子研究上取得了一系列重要实验进展,包括发现了两个超子Ξ(16 20)和Ω(20 12)、一个粲重子Ξc(29 30)等新的重子,并首次测量了粲重子Ξc衰变的绝对分支比等,为完善重子谱和深入理解强相互作用性质提供了关键的实验数据。     

Electrical and Thermoelectrical Behavior of Binary Composites of Phosphate Glass Loaded with Zinc Fillers: Promising Materials for Photovoltaic’s

Homogeneous xPbO?(1?x) P₂O₅ glasses where 0 % :σ x<100 % have been successfully synthesized using a melt‐quenching method. The short range structures of the prepared samples were examined by Fourier transform infrared spectroscopy, x‐powder diffraction and scanning electron microscopy. The most stable vitreous phase is of composition 45 mol%PbO‐55 mol%P₂O₅; it was loaded with zinc volume fraction. We carried out experimental and simulative investigations of the electrical characteristics of p? n junction; the obtained results indicated that conductivity of the composites increases by increasing dopent concentration. It was also observed that the current voltage characteristics of the composite were found to be ohmic in nature, wherein drastic drop of the electrical conduction was observed at an accurate temperature of 405 K. Electrical behavior of the composites as function of filler concentration and versus temperature were explained respectively by percolation theory and positive temperature coefficient effect.     

Cytotoxic agents for KB and SiHa cells from n-hexane fraction of Cissampelos pareira and its chemical composition

Eleven constituents were characterised by gas chromatography–mass spectrometry analysis, and five molecules were isolated using column chromatography. The in vitro study of the extract and isolated molecules against KB and SiHa cell lines revealed oleanolic acid (1) and oleic acid (2) as potent cytotoxic molecules with potential anticancer activity. The IC₅₀ values of n-hexane extract (CPHF), oleanolic acid (1) and oleic acid (2) were >300, 56.08 and 70.7 μg/mL (μM), respectively, against KB cell lines and >300, 47.24 and 80.2 μg/mL (μM), respectively, against SiHa cell lines.     

渤海稠油及其组分中杂原子化合物的负离子电喷雾-高分辨质谱分析

采用沉淀法和色谱分离法将渤海某油田稠油分离成沥青质、胶质、剩余分3个组分。采用负离子电喷雾技术(ESI)结合高分辨傅立叶变换离子回旋共振质谱仪(FT-ICR MS)研究了该稠油及各组分的分子组成。结果表明,剩余分中有较少的极性杂原子化合物能被负离子ESI电离,如N_1,N_1O_1,O_1和O_2类,其等效双键数(DBE)较小。胶质和原油中极性化合物有相同的杂原子类型,包括N_1,N_1O_1,N_1O_2,N_2,N_2O_2S_1,O_1,O_2,其中胶质和原油中N_1,O_1,O_2类化合物的DBE-碳数分布图相似。沥青质中富集高缩合度且多杂原子的酸性化合物,如含杂原子N_,S的氧化程度高的化合物(N_2O_1,N_1O_3,S_1O_3)及O_3类化合物,这些物质具有较高的界面活性,易吸附在界面上促进界面张力降低和增强界面膜强度,从而有利于乳状液稳定存在。N_1O_1,N_1O_2,N_1O_3类化合物,N_2O_1类化合物可能分别是N_1化合物,N_2化合物的氧化降解产物;随着氧化降解程度增加,降解产物的极性明显增强。     

Interrelationship between total volatile organic compounds emissions,structure and properties of natural rubber/polycaprolactone bio-blends cross-linked with peroxides

Natural rubber/polycaprolactone (NR/PCL) bio-based blends with different organic peroxides were prepared using an internal batch mixer and subsequently cross-linked at 170 °C. Two types of commonly used organic peroxides, dicumyl peroxide and di(tert-butylperoxyisopropyl)benzene peroxide, were applied as free-radical initiator. Cross-linking efficiency of NR/PCL blends were investigated using oscillating disc rheometer measurements, followed by infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis and tensile testing. Total volatile organic compounds (TVOCs) emissions were determined using headspace analysis integrated with gas chromatography with flame ionization detector. Determined TVOCs emissions varying in range 21.6–52.1 μg/g and generally value of this parameter decreased with increasing content of PCL phase in studied blends or with application of more efficient di(tert-butylperoxyisopropyl)benzene peroxide as cross-linking agent. It was found that increasing of TVOCs parameter indicated deterioration of mechanical properties of NR/PCL blends, which corresponded with the changes in chemical structure and thermal properties of cross-linked NR/PCL. This confirms that evaluation of TVOCs parameter is interesting alternative for “conventional methods” to characterization of the studied bio-based blends.