粉煤灰用于废水处理的研究进展

在双碳目标下,各行业都要求实现低碳循环发展,利用粉煤灰对废水进行处理是一种行之有效的资源循环利用的低碳环保措施。对粉煤灰在处理含油废水中的影响因素、粉煤灰改性的方法及改性粉煤灰处理含N、P废水、印染废水、重金属废水和含油废水上的应用进行了概述,分析了存在的问题,并探讨了该技术在今后的应用前景。

匀浆膳联合蛋白肽对脑卒中患者营养干预评价

目的制备适用于脑卒中合并2型糖尿病患者的匀浆膳,并观察自制匀浆膳联合蛋白肽在该类患者中的临床应用效果。方法依据脑卒中合并2型糖尿病患者特点制备匀浆膳并将制备好的匀浆膳应用于50例该类患者中,随机分为2组,匀浆膳加蛋白肽组每日给予1 890 kcal(1 kcal=4.186 kJ)自制匀浆膳并联合应用20 g蛋白肽,匀浆膳组每日给予1 890 kcal自制匀浆膳,观察4周,记录患者营养支持前和营养支持两周后、四周后的相关生化指标。结果每组患者的空腹血糖、餐后2 h血糖、总蛋白、白蛋白、前白蛋白、血红蛋白、肌酐、钠离子等在营养支持前、支持两周和四周后,差异具有统计学意义。对于前白蛋白指标,匀浆膳加蛋白肽组和匀浆膳组的差异具有统计学意义。结论自制匀浆膳联合蛋白肽有利于患者血糖控制、营养状况改善以及钠离子调节。

考虑水化学损伤的砂岩流变损伤本构模型

通过对已有的水化学溶液腐蚀作用后红砂岩三轴蠕变试验结果的分析,可知水化学作用能够加快岩石损伤的发展,增强红砂岩的蠕变效应。根据水岩化学作用的动力学理论,将红砂岩中可溶解胶结物的流失作为水化学腐蚀作用下岩石力学性能劣化的根本原因。通过化学反应速率方程和测定浸泡过程中溶液p H值的变化,定义了考虑初始p H值和时间的化学损伤因子。考虑流变过程中的应力损伤,基于广义Kelvin模型,提出了考虑水化学作用的砂岩流变损伤本构模型。通过对水化学作用下红砂岩流变试验结果进行模拟,对该模型进行了参数辨识和验证。结果表明,所提出的模型能够较好地反映水化学作用下砂岩的流变特性,具有有效性和合理性。

基于粒子群-变分模态分解、非线性自回归神经网络与门控循环单元的滑坡位移动态预测模型研究

以三峡库区八字门阶跃型滑坡为例,针对静态机器学习模型在周期项位移预测中的不足以及高频随机项位移预测困难等问题,提出了一种新的滑坡位移预测方法。基于时间序列分解思想,采用粒子群算法(PSO)对变分模态分解(VMD)进行参数寻优,并将位移时间序列分解为趋势项、周期项和随机项。趋势项主要受滑坡内部因素影响,采用傅里叶曲线进行拟合预测;周期项由外部因素导致,基于格兰杰因果检验进行成因分析,并引入一种对时间序列历史状态具有较高敏感性的非线性自回归神经网络(NARX)进行预测;随机项频率较高且影响因素无法判定,采用一维门控循环单元(GRU)进行预测。最后将各分量预测位移进行叠加重构,实现滑坡累计位移的预测。结果表明,提出的(PSO-VMD)-NARX-GRU滑坡位移动态预测模型精度较高,且各位移分量预测精度明显高于静态模型中BP神经网络、支持向量机(SVM)和传统自回归模型ARIMA,可为阶跃型滑坡位移预测提供参考。

即食果蔬泥制作工艺研究及产品开发

本试验围绕婴幼儿果蔬辅食产品的开发,以苹果、香蕉、胡萝卜、南瓜、番茄5种原料为试材,通过不同比例搭配调配出口感佳、营养丰富的果蔬泥婴幼儿辅食产品。并通过单因素试验和正交试验进行优化,确定了苹果香蕉泥最佳生产工艺条件为苹果泥与香蕉泥的比例8:2,苹果预煮时间4min,香蕉预煮时间8min,苹果泥中VC添加量为1.5%,香蕉泥中VC添加量为1.0%;南瓜番茄泥的最佳工艺条件为南瓜泥与番茄泥的比例7:3,南瓜预煮时间15min,番茄预煮时间6min;南瓜胡萝卜泥的最佳工艺条件为南瓜泥与胡萝卜泥的比例6:4,南瓜预煮时间15min,胡萝卜预煮时间15min。在此条件下,制得的果蔬泥产品无添加,营养丰富,口感细腻。

面向海量空间数据的分布式距离连接算法

空间距离连接是空间数据分析最基本的操作之一,具有广泛的应用场景。针对现有分布式方法的空间域选取过大、数据倾斜、自连接较慢的问题,提出了一种新的面向海量空间数据的分布式距离连接算法JUST-Join。首先,JUST-Join仅选取必要的空间区域作为全局域,能够提前过滤数据,减少无效的数据传输和不必要的计算开销;然后,同时考虑了参与连接的两个数据集的分布,从而缓解了数据倾斜问题;最后,针对自连接情形的冗余计算,采用平面扫描算法来进一步提高效率。文中使用Spark实现了JUST-Join算法,并利用真实的数据集做了大量实验。实验结果表明,JUST-Join算法在效率和扩展性方面都优于现有的最先进的分布式空间分析系统。

Stress dependent permeability and porosity of low-permeability rock

The seepage property of low-permeability rock is of significant importance for the design and safety analysis of underground cavities. By using a self-developed test system, both permeability and porosity of granite from an underground oil storage depot were measured. In order to study the influence of rock types on permeability, a tight sandstone was selected as a contrast. The experimental results suggested that the porosity of this granite is less than 5% and permeability is low to 10–20 m^2 within the range of effective stress. During the loading process, both exponential relationship and power law can be utilized to describe the relationship between effective stress and permeability. However, power law matches the experimental data better during the unloading condition. The stress dependent porosity of granite during loading process can be described via an exponential relationship while the match between the model and experimental data can be improved by a power law in unloading paths. The correlation of permeability and porosity can be described in a power law form. Besides, granite shows great different evolution rules in permeability and porosity from sandstone. It is inferred that this difference can be attributed to the preparing of samples and different movements of microstructures subjected to effective stress.

Creep properties and permeability evolution in triaxial rheological tests of hard rock in dam foundation

Triaxial creep tests were carried out under seepage pressure by using rock servo-controlled triaxial rheology testing equipment. Based on experimental results, rock rheological properties influenced by seepage-stress coupling were studied, and variations of seepage rate with time in complete creep processes of rock were analyzed. It is shown that, when the applied stress is less than failure stress level, the creep deformation is not obvious, and its main form is steady-state creep. When applied stress level is greater than or less than but close to fracture stress, it is easier to see the increase of creep deformation and the more obvious accelerative creep characteristics. The circumferential creep deformation is obviously higher than the axial creep deformation. At the stage of steady-state creep, the average of seepage flow rate is about 4.7×10-9 rn/s at confining pressure （tr3） of 2 MPa, and is about 3.9×10-9 m/s at a3 of 6 MPa. It is seen that the seepage flow rate at or3 of 2 MPa in this case is obviously larger than that at tr3 of 6 MPa. At the stage of creep acceleration, the seepage flow rate is markedly increased with the increase of time. The variation of rock permeability is directly connected to the growth and evolution of creep crack. It is suggested that the permeability coefficient in complete creep processes of rock is not a constant, but is a function of rock creep strain, confining pressure, damage variable and pore water pressure. The results can be considered to provide a reliable reference for the establishment of rock rheological model and parameter identification.

Micromorphological characterization and random reconstruction of 3D particles based on spherical harmonic analysis

The microscopic characteristics of skeletal particles in rock and soil media have important effects on macroscopic mechanical properties. A mathematical procedure called spherical harmonic function analysis was here developed to characterize micromorphology of particles and determine the meso effects in a discrete manner. This method has strong mathematical properties with respect to orthogonality and rotating invariance. It was used here to characterize and reconstruct particle micromorphology in three-dimensional space. The applicability and accuracy of the method were assessed through comparison of basic geometric properties such as volume and surface area. The results show that the micromorphological characteristics of reproduced particles become more and more readily distinguishable as the reproduced order number of spherical harmonic function increases, and the error can be brought below 5% when the order number reaches 10. This level of precision is sharp enough to distinguish the characteristics of real particles. Reconstructed particles of the same size but different reconstructed orders were used to form cylindrical samples, and the stress-strain curves of these samples filled with different-order particles which have their mutual morphological features were compared using PFC3D. Results show that the higher the spherical harmonic order of reconstructed particles, the lower the initial compression modulus and the larger the strain at peak intensity. However, peak strength shows only a random relationship to spherical harmonic order. Microstructure reconstruction was here shown to be an efficient means of numerically simulating of multi-scale rock and soil media and studying the mechanical properties of soil samples.

Investigation on jointed rock strength based on fractal theory

Strength of discontinuities with complex structure is an important topic in rock engineering.A large number of studies have shown that fractal is applicable in the description of this discontinuity.Using fractal interpolation method for the generation of rock joints,numerical experiments of shear tests of the jointed rock mass model were carried out using FLAC^(3D).The test results show that the real rock joints can be simulated by fractal curves obtained by fractal interpolation.The fractal dimension is an important factor for the characterization of jointed rock mass;test results show that the fractal dimension of rock joints can be related to the equivalent cohesion strength and shear strength of the rock mass.When the fractal dimension of the joint surface is less than critical dimension Dc 1.404,the cohesion strength and shear strength of the rock mass increase as the fractal dimension increases;for larger fractal dimensions,all mechanical parameters decrease as the fractal dimension increases.Joint surfaces with different degrees of roughness were obtained by the fractal interpolation method.Three types of failure modes were observed in the tests:climbing slip failure,climbing gnawing fracture,and non-climbing gnawing fracture.

Non-identical Neural Network Synchronization Study Based on an Adaptive Learning Rule of Synapses

An adaptive learning rule of synapses is proposed for a general asymmetric non-identical neural network.Its feasibility is proved by the Lasalle principle.Numerical simulation results show that synaptic connection weight can converge to an appropriate strength and the identical network comes to synchronization.Furthermore,by this approach of learning,a non-identical neural population can still reach synchronization.This means that the learning rule has robustness on mismatch parameters.The firing rhythm of the neural population is totally dependent on topological properties,which promotes our understanding of neuron population activities.

Influence of Surface Topography on the Tactile Friction of Medical Compression Textiles against a Mechanical Skin Model

Influence of surface topography on the tactile friction of medical compression textiles was studied in this paper. The friction behavior was investigated for three kinds of medical textiles with various structures and compositions by using a textile friction analyzer under dry condition. In order to simulate the contacts of textiles/human finger, a mechanical skin model with similar texture to the skin and applied normal load oflN were selected. Meanwhile, the 3D surface topography of textiles was measured using a digital microscope. The topographical data were analyzed concerning height distribution and material ratio, and the real contact area was estimated as a function of penetration depth. Results showed that the investigated textiles revealed a significant variation on the friction coefficients, which were （ 0.41 ± 0.01 ） （ polyamide, jersey 2 × 2 ）, （0.56 ± 0. 01） （cotton, jersey 2×2） and （0. 47 ± 0. 01） （polyamide, jersey 1 × 1 ）, respectively. The textile with higher friction coefficient was found to own a relative compact and homogenous surface and larger contact area, vice versa.

Anthropomorphic Classification of Tactile Qualities of Woven Fabrics Based on Skin/Textile Friction-Induced Vibrations

The common method classifying tactile qualities of fabrics is indirectly based on their difference of purely mechanical and physical properties. When human skin slides across fabric surfaces, the friction interaction between fabrics and skin will occur and trigger the cutaneouS tactile receptors, which are responsible for perceived tactile sensation. By the extracted features from friction- induced vibration signals, this paper presents an anthropomorphic classification method classifying tactile qualities of fabrics. The friction-induced vibration signals are recorded by a three-axis accelerator sensor, and the entice testing procedure is conducted in an anthropomorphic way to obtain vibration signals. The fast Fourier transform （FFT） is applied to analyzing the recoded signals, and then the classification features are extracted from the FFT data by the neurophysiological properties of tactile receptors. The extracted features are used to classify fabric samples by the softness sensation and the roughness sensation, respectively, and the classification performance is checked by a comparison with those in a sensory evaluation procedure. The results showed that the anthropomorphic objective classification method was precise and efficient to clarify tactile qualities of woven fabrics.

Dynamics of a Cortical Neural Network Based on a Simple Model

The collective dynamics of a randomly connected neuronal network motivated by the anatomy of a mammalian cortex based on a simple model are studied.This simple model can not only reproduce the rich behaviors of biological neurons but also has only two equations and one nonlinear term.By varying some key parameters,such as the connection weights of neurons,the external current injection and the noise of intensity,this neuronal network will exhibit various collective behaviors.It is demonstrated that the synchronization status of the neuronal network has a strong relationship with the key parameters and the external current has more influence on the spiking of inhibitory neurons than that of excitatory neurons.These results may be instructive in understanding the collective dynamics of a mammalian cortex.

Approach of Complex Networks for the Determination of Brain Death

In clinical practice,brain death is the irreversible end of all brain activity.Compared to current statistical methods for the determination of brain death,we focus on the approach of complex networks for real-world electroencephalography in its determination.Brain functional networks constructed by correlation analysis are derived,and statistical network quantities used for distinguishing the patients in coma or brain death state,such as average strength,clustering coefficient and average path length,are calculated.Numerical results show that the values of network quantities of patients in coma state are larger than those of patients in brain death state.Our findings might provide valuable insights on the determination of brain death.

A Neurodynamical Model for Selective Visual Attention

A neurodynamical model for selective visual attention considering orientation preference is proposed.Since orientation preference is one of the most important properties of neurons in the primary visual cortex,it should be fully considered besides external stimuli intensity.By tuning the parameter of orientation preference,the regimes of synchronous dynamics associated with the development of the attention focus are studied.The attention focus is represented by those peripheral neurons that generate spikes synchronously with the central neuron while the activity of other peripheral neurons is suppressed.Such dynamics correspond to the partial synchronization mode.Simulation results show that the model can sequentially select objects with different orientation preferences and has a reliable shift of attention from one object to another,which are consistent with the experimental results that neurons with different orientation preferences are laid out in pinwheel patterns.

300例RhD阴性患者中的Rh分型在不同民族之间的分布研究

目的:研究300例RhD阴性患者中的Rh分型在不同民族之间的分布情况。方法:选取300例RhD阴性患者为研究对象,进行表型分型,检测其Rh分型,并对结果进行研究分析,观察不同民族患者之间的差异性及分布情况。结果:维吾尔族RhD阴性患者阴性率为5.9%(240/4042),显著高于其它民族,其RhD阴性血清学表型分布不平衡,多见于ccdee,占总比的86%,其他表型占比相对较少。结论:RhD阴性患者中的Rh分型在不同民族之间的分布情况与本地区疾病及健康普查情况联系密切,完善相关基因分型策略具有十分重要的指导意义,为精准输血保驾护航。

血栓弹力图对重症感染患者凝血功能评估的临床价值

目的比较血栓弹力图(TEG)和常规凝血试验对重症感染患者凝血功能评估的临床价值。方法回顾性选择2016年1月到2018年12月新疆自治区人民医院诊治的重症感染患者70例作为重症感染组,选择同时期健康体检患者50例作为正常组,两组均进行常规凝血试验与TEG试验。分析患者的凝血功能[凝血酶原时间(PT)、活化部分凝血活酶时间(APTT)、D-二聚体(DD)、纤维蛋白原(FIB)、国际标准化比值(INR)、纤维蛋白原降解产物(FDP)]和TEG参数[凝血反应时间(R值)、血凝块凝固时间(K值)、凝固角(α角)、最大血块强度(MA)、凝血综合指数(CI)]的相关性,比较常规凝血试验与TEG试验对凝血异常的诊断率。结果重症感染组常规凝血检测的凝血功能指标PT、APTT明显短于正常组(P均<0.01),而DD、FIB、FDP以及INR水平明显高于正常组(P均<0.01);TEG检测的TEG指标R值、K值明显低于正常组(P均<0.01),α值、MA值、CI值明显高于正常组(P均<0.01)。Pearson线性相关分析显示,R值、K值与PT、APTT呈正相关性,与DD、FIB、FDP、INR呈负相关;α值、MA值、CI值与PT、APTT呈负相关,与DD、FIB、FDP、INR呈正相关。TEG检测重症感染组患者发现凝血异常率90.00%(63/70),明显高于常规凝血检测凝血异常的75.71%(53/70)(χ^2=5.028,P=0024)。结论重症感染患者的常规凝血试验各指标与TEG各项参数存在明显的相关性,两种检测方法对患者凝血功能障碍的评估及其纠正治疗均有一定的临床指导价值,TEG检测对患者凝血功能异常的诊断更敏感。