煤峪口矿81010工作面煤层底板裂隙发育特征及防治

针对煤炭开采过程中出现的突水事故,采用RFPA数值模拟软件建立采动模型,对底板裂隙破断过程和声发射进行模拟,研究煤层底板采动裂隙扩展突水通道,结果表明:离断层越近,断层内水压导升高度越高,断层出现活化,裂隙扩展发育,最终贯通形成导水通道,在进行注浆改造后,单个钻孔的最大涌水量为8 m³/h,说明注浆加固防治水效果较好,能确保工作面的安全回采。     

Inhibitory effects of curcumin and piperine on fluorescent advanced glycation end products formation in a bovine serum albumin–fructose model

This study investigated the inhibitory effects of curcumin and piperine on fluorescent advanced glycation end products (fAGEs) formation in a bovine serum albumin (BSA)–fructose model. Model systems of BSA and fructose were prepared, and curcumin or piperine was added. fAGEs and BSA oxidation product (dityrosine, kynurenine and N'-formylkynurenine) contents were determined. The results showed that fAGEs content decreased with increasing concentration of curcumin and piperine (P < 0.05). Addition of curcumin and piperine at 160 µg mL⁻¹ could inhibit fluorescent AGEs by 100% and 93% respectively. Dityrosine and N'-formylkynurenine contents decreased as curcumin and piperine concentration increased (P < 0.05). Furthermore, the result of principal component analysis indicated that curcumin and piperine markedly impeded BSA oxidation, resulting in a lower level of fAGEs in model systems. Therefore, adding curcumin and piperine may facilitate reduced fAGEs levels in BSA–fructose model.     

Acid–base transport model depicting the dynamic pH response of interfacial reactions

Acid–base transport is integral to many important interfacial reactions in various fields of chemistry, but its theoretical foundation is lacked. Herein, a common acid–base transport model is established owing to the success in deriving buffer transport equations. This model is applicable to most buffer systems by flexibly integrating the transport equations in terms of buffer components, and is verified through the model relationships of buffer transport limiting current by using hydrogen evolution reaction experiments. Based on model calculations, two diagram approaches are proposed to depict the dynamic pH response and aid buffer operation optimizations. The model and methods allow us to quantify the rate-limiting effect of acid–base transport on interfacial reactions and to precisely control the effect through medium regulations. Furthermore, the model has laid the foundation of dynamic pH effect on species transformation and process mechanism, which can be of wide interest in the chemistry encompassing interfacial reactions.     

Investigation into adsorption equilibrium and thermodynamics for water vapor on montmorillonite clay

The isothermal adsorption curves for water vapor on montmorillonite were measured by a gravimetric adsorption system. Dent's model was employed to estimate the adsorption behaviors of water vapor on primary adsorption sites and secondary adsorption sites. The thermodynamics analysis of water vapor adsorption was performed. At low vapor pressure region, primary adsorption predominates, and with increasing vapor pressure, secondary adsorption becomes notable. Primary adsorption sites have an evidently stronger adsorption affinity than secondary adsorption sites. With increasing vapor pressure, Gibbs free energy variation rapidly increases and then reduces slowly. Although increasing vapor pressure raises adsorption spontaneity on primary adsorption sites, the enhancement in vapor pressure decreases the spontaneity of water vapor adsorption on secondary adsorption sites. As adsorbed loading increases, isosteric heat of adsorption and entropy loss decrease first and then increase quickly. The gradually growing water clusters are responsible for the increase of entropy loss at late stage.     

Effect of slot-die configurations on coating gap dependence of maximum and minimum wet thicknesses

The dependence of the maximum and minimum wet thicknesses on the coating gap is derived for the slot-die coating process, under different slot-die configurations. Analytical expressions for the wet thickness and its derivative with respect to the coating gap are obtained using a simple flow model. The results indicate that, as expected, the minimum wet thickness increases linearly with the coating gap; however, the maximum wet thickness demonstrates a counterintuitive trend of decreasing as the coating gap increases, when a specific slot-die configuration is assumed. Moreover, the results are also validated by numerically solving the complete two-dimensional (2D) Navier–Stokes equation.     

“灰绿”协同措施对银川市合流制溢流污染的影响EI北大核心CSCD

针对合流制管网系统在雨天溢流污染严重,造成城市水体黑臭现象的问题,以银川市某高密度城区合流制管网系统为例,基于SWMM模型,在短历时设计降雨和长历时设计降雨两种条件下,模拟分析了合流制溢流(CSO)调蓄池、雨污管道混错接改造、绿化带海绵化改造等“灰绿”协同措施对CSO污染的影响。结果表明:CSO调蓄池、雨污管道混错接改造、绿化带海绵化改造及“灰绿”措施结合4种方案在短历时、长历时设计降雨条件下,随着降水量的增加,溢流水量及溢流污染物负荷均增加,溢流削减率均逐渐减小,其中“灰绿”措施结合方案对溢流污染的削减效果最为显著;重现期小于5 a时,溢流水量削减率与溢流污染物负荷削减率基本达到80%;降雨条件为中雨时,污染物负荷削减率基本达到75%;重现期为20 a时,溢流水量削减率及TSS、COD、TP、NH^(+)_(4)-N负荷削减率分别达到64%、70%、70%、70%、70%;降雨条件为大雨时,溢流水量削减率及TSS、COD、TP、NH^(+)_(4)-N负荷削减率分别达到28%、32%、26%、31%、33%。     

基于卷积神经网络的5G蜂窝网络无线定位方法

5G蜂窝网络发展迅猛，其覆盖面积将逐渐增大，因此使用5G蜂窝网络进行定位是有研究潜力的研究方向。本文提出一种新的深度学习技术来实现高效、高精度和低占用的定位，以代替传统指纹定位过程中繁重的指纹库生成以及距离计算。该方法建立了一个特殊的卷积神经网络，并根据5G天线信号的接收信号强度指示、相位和到达角等特征量，选择合适的输入数据格式构造样本组建训练集，对该卷积神经网络进行训练。训练得到的卷积神经网络可以替代指纹定位中的庞大指纹库，非常有利于直接在5G移动设备端实现定位。虽然卷积神经网络在训练过程中需要大量时间，但在训练完毕后直接进行分类定位的速度非常快，可以保障定位实现的实时性。本文所实现的卷积神经网络权重与偏置所占内存不到0.5 MB，且能够在实际应用环境中以95%的定位准确率以及0.1 m的平均定位精度实现高精度定位。     

疫情下电磁场理论课程的网络教学

本文主要总结了新冠疫情期间作者的电磁场理论课程在线教学经验。对比分析了录播和直播的优缺点后,选择录播教学方式。基于超星网络教学平台,展示了录播网络教学的具体措施,包括网上答疑和学习效果检查以及在线批改作业等。给出了网络教学可以为线下教学继续使用的方法和手段,为疫情结束后的正常教学提供了新的网络教学补充措施。     

5G核心网业务模型的智能化预测研究

摘 要：核心网业务模型的建立是5G网络容量规划和网络建设的基础，通过现有方法得到的理论业务模型是静态不可变的且与实际网络存在偏离。为了克服现有5G核心网业务模型与现网模型适配性较差以及规划设备无法满足用户实际业务需求的问题，提出了一种长短期记忆（long short-term memory，LSTM）网络与卷积LSTM （convolution LSTM，ConvLSTM）网络双通道融合的 5G 核心网业务模型预测方法。该方法基于人工智能（artificial intelligence，AI）技术以实现高质量的核心网业务模型的智能预测，形成数据反馈闭环，实现网络自优化调整，助力网络智能化建设。