Effect of roughness on the shear behavior of rock joints subjected to impact loading

The shear behavior is regarded as the dominant property of rock joints and is dramatically affected by the joint surface roughness.To date,the effect of surface roughness on the shear behavior of rock joints under static or cyclic loading conditions has been extensively studied,but such effect under impact loading conditions keeps unclear.To address this issue,a series of impact shear tests was performed using a novel-designed dynamic experimental system combined with the digital image correlation(DIC)technique.The dynamic shear strength,deformability and failure mode of the jointed specimens with various joint roughness coefficients(JRC)are comprehensively analyzed.Results show that the shear strength and shear displacement characteristics of the rock joint under the impact loading keep consistent with those under static loading conditions.However,the temporal variations of shear stress,slip displacement and normal displacement under the impact loading conditions show obviously different behaviors.An elastic rebound of the slip displacement occurs during the impact shearing and its value increases with increasing joint roughness.Two identifiable stages(i.e.compression and dilation)are observed in the normal displacement curves for the rougher rock joints,whereas the joints with small roughness only manifest normal compression displacement.Besides,as the roughness increases,the maximum compression tends to decrease,while the maximum dilation gradually increases.More-over,the microstructural analysis based on scanning electron microscope(SEM)suggests that the roughness significantly affects the characteristics of the shear fractured zone enclosing the joint surface.

Novel Distance Measures on Hesitant Fuzzy Sets Based on Equal-Probability Transformation and Their Application in Decision Making on Intersection Traffic Control

The purpose of this study is to reduce the uncertainty in the calculation process on hesitant fuzzy sets(HFSs).The innovation of this study is to unify the cardinal numbers of hesitant fuzzy elements(HFEs)in a special way.Firstly,a probability density function is assigned for any given HFE.Thereafter,equal-probability transformation is introduced to transform HFEs with different cardinal numbers on the condition into the same probability density function.The characteristic of this transformation is that the higher the consistency of the membership degrees in HFEs,the higher the credibility of the mentioned membership degrees is,then,the bigger the probability density values for them are.According to this transformation technique,a set of novel distance measures on HFSs is provided.Finally,an illustrative example of intersection traffic control is introduced to show the usefulness of the given distance measures.The example also shows that this study is a good complement to operation theories on HFSs.

Some Inequalities of Hermite-Hadamard Type for Functions Whose 3rd Derivatives Are <i>P</i>-Convex

In the paper, the authors establish some new Hermite-Hadamard type inequalities for functions whose 3rd derivatives are P-convex.

Clinicopathologic significance of CXCR4 and Nrf2 in colorectal cancer

The CXCR4 and Nrf2 signaling pathways are abnormally activated in response to cellular stress in various types of human cancers. In this study, we examined the expression of CXCR4 and Nrf2 in colorectal cancer （CRC） tissue specimens and investigated their correlation with patient clinicopathologic characteristics. We determined CXCR4 and Nrf2 expression in 76 CRC tissue specimens and paired normal tissue specimens by immunohistochemistry and real-time PCR. We found that the protein and mRNA transcript levels of CXCR4 were significantly higher in CRC tissue specimens than in paired normal tissues, while the expressions of Nrf2 protein and mRNA were increased in CRC tissues compared to distant non-cancerous tissues. High expression level of CXCR4 was positively correlated with poorly differentiated （P=0.031）, more advanced tumor-node-metastasis （TNM） stage （P=0.019）, lymph node metastasis （P=0.007） and distant metastasis （P=0.018）. However, the expression of Nrf2 protein was positively correlated with larger tumor size （P=0.049）, more advanced TNM stage （P=0.013）, lymph node metastasis （P=0.016） and distant metastasis （P=0.023）. Moreover, there was a strong relationship between CXCR4 and Nrf2 expression in CRC tissues, indicating that high Nrf2 expression may contribute to CXCR4 overexpression. In addition, combined expression of CXCR4 and Nrf2 strongly correlated with lymph node metastasis and distant metastasis （P=0.003）. Furthermore, we found that combined high expression of CXCR4 and Nrf2 had stronger correlation with lymph node metastasis and distant metastasis than any single molecule did. This study indicated that the abnormal expression of CXCR4 and Nrf2 contributed to the progression of CRC.

Numerical Investigations of Transverse Gradient Undulator Based on Novel Light Sources

With the stat-of-the-art laser technique, the quality of electron beam generated from LPA （laser-plasma accelerator） is now becoming much better. The natural merits of electron beam from LPA, e.g., high peak current, ultra-low emittance and ultra-short bunch length, etc., pave the way to the novel light sources, especially in the realm of developing much more compact x-ray light sources, e.g., table-top XFEL （x-ray free-electron laser）. However, the radiation power is limited by the rather larger energy spread than conventional radio-frequency electron LINAC （linear accelerator）. Luckily, much more power could be extracted by using the undulator with transverse gradient when energy spread effect could be compensated. In this paper, we introduce a novel soit x-ray light source driven by LPA together with TGU （transverse gradient undulator） technique, meanwhile we present a simple idea on how to achieve much higher rep-rate （e.g., -100 kHz） FELs （free-electron lasers） boosted by TGU based on storage rings.

Multiscale Modeling of Magnetic Distribution of Ribbon Magnetic Cores

The multiscale finite element method(MsFEM)combined with conventional finite element method(CFEM)is proposed to solve static magnetic field in the ribbon magnetic core with non-periodical corners considered.Firstly,a simple 2-dimensional electrostatic problem is used to introduce the MsFEM implementation process.The results are compared to analytical method,as well as conventional FEM.Then,an exam-ple of magneto-static problem is considered for a ribbon magnetic core built sheet by sheet as well as corners taken into considera-tion.Conventional FEM and MsFEM are used to compute the magneto-static field by adopting scalar magnetic potential.Both magnetic potential and magnetic flux density on a certain path are compared.It is shown that the results obtained by MsFEM agree well with the one from conventional FEM.Moreover,MsFEM combined with FEM is potentially a general strategy for mul-tiscale modeling of ribbon magnetic cores with complex and non-periodical structures considered,like corners and T-joints,which can effectively reduce the computational cost.

Message from Editors

ELECTRICAL machines are the hearts of many modern appliances and industrial systems.Their analysis and design optimization processes become more and more complex as more disciplines/domains and constraints are involved,such as electromagnetics,structural mechanics,heat transfer,and control strategies.To achieve multi-objective optimal performance of electrical machines and systems for applications of challenging specifications,such as electric vehicles and wind power generation,it is of great significance to conduct a multi-physics analysis and take a systematic design optimization approach.On the other hand,the performance and quality of batch produced electrical machines depend highly on the material diversities and manufacturing tolerances.

血清细胞因子预测急性脑梗死后肺炎的价值

目的研究血清细胞因子与急性脑梗死后肺炎发生的相关性并探讨其预测价值。方法选取在同济大学附属东方医院神经内科重症病房收治的99例急性脑梗死患者为研究对象,其中男性70例(70.71%),女性29例(29.29%);年龄27~95岁,平均(67±13)岁。发病48 h内检测血清十二项细胞因子浓度,包括白细胞介素(interleukin,IL)-1β,IL-2,IL-4,IL-5,IL-6,IL-8,IL-10,IL-12P70,IL-17A,干扰素(interferon,IFN)-α,IFN-γ,肿瘤坏死因子(tumor necrosis factor,TNF)-α以及血清白蛋白、球蛋白、外周血白细胞计数、外周血淋巴细胞计数;依据研究对象其后是否发生肺炎分为肺炎组(44例)和非肺炎组(55例),应用二元Logistic回归分析明确十二项细胞因子是否为急性脑梗死后肺炎发生的独立预测因素。结果二元Logistic回归分析显示,血清IL-10浓度升高(OR 1.24,95%CI 1.01~1.52,P=0.039)和外周血白细胞计数增加(OR 1.50,95%CI 1.18~1.92,P=0.001)为急性脑梗死后肺炎的独立预测因素,发病48 h内血清IL-10>2.50ng/L预测急性脑梗死后肺炎的敏感度为61.36%,特异度为64.29%,外周血白细胞>10.00×109/L的敏感度为50.00%,特异度为81.48%,两者联合预测急性脑梗死后肺炎的敏感度为34.09%,特异度为83.33%。结论急性脑梗死早期血清IL-10升高和外周血白细胞计数增加有助于预测急性脑梗死后肺炎的发生,特异度较高、但敏感度较低。

私密性越高越好吗?办公场所私密性供需匹配对员工情绪耗竭和离职意愿的影响研究

办公场所提供的私密性越高越好吗?多高的私密性能够为员工带来最佳的工作场所体验?本研究基于人—环境匹配理论,认为员工在办公场所中不仅体验到组织实际提供的私密性,也具有个体期望的私密性,但是以往研究多关注实际私密性高低对员工的影响,忽视了实际私密性与期望私密性之间的匹配状态对员工的影响作用。本研究系统分析了办公场所实际私密性与期望私密性之间的一致性对员工消极工作态度的影响作用。基于290份两阶段问卷数据的统计分析结果表明:实际私密性与期望私密性的匹配状态会对情绪耗竭产生影响,并最终影响到员工的离职意愿。具体而言,实际私密性与期望私密性之间越不一致,员工的情绪耗竭越高;“实际低—期望低”情境比“实际高—期望高”情境导致更高的情绪耗竭;“实际低—期望高”情境比“实际高—期望低”情境导致更高的情绪耗竭;情绪耗竭在办公场所私密性供需匹配与员工离职意愿之间起中介作用。本研究揭示了实际私密性与期望私密性之间不同的匹配状态会对员工产生不同的影响。

基于CT扫描的花岗岩三维数值试件重构模型及应用

岩石细观结构控制宏观破裂模式,建立一种表征岩石细观结构的数值模型重构方法并能够嵌入到力学模型中计算岩石破坏过程应力分布,对于揭示岩石破坏机理具有重要的理论意义.论文以花岗岩试件为研究对象,借助于先进的CT技术获取试件内部结构切片图像,利用数字图像处理技术实现了基于CT图像的花岗岩试件结构的识别和表征,基于矢量化方法和岩石破裂过程分析系统RFPA3D建立了花岗岩三维数值试件,对花岗岩试件单轴压缩破裂过程进行了数值模拟.通过数值试验结果与物理实验结果对比发现,基于CT扫描的花岗岩数值试件真实表征了岩石细观结构,所以力学模拟得到的破裂模式与室内物理实验得到的破裂模式相似,同时能够解译岩石破裂力学机理,为深入研究岩石、复合材料等力学特征提供了一种可行方法.

Detection of damage locations and damage steps in pile foundations using acoustic emissions with deep learning technology

The aim of this study is to propose a new detection method for determining the damage locations in pile foundations based on deep learning using acoustic emission data.First,the damage location is simulated using a back propagation neural network deep learning model with an acoustic emission data set acquired from pile hit experiments.In particular,the damage location is identified using two parameters:the pile location(PL)and the distance from the pile cap(DS).This study investigates the influences of various acoustic emission parameters,numbers of sensors,sensor installation locations,and the time difference on the prediction accuracy of PL and DS.In addition,correlations between the damage location and acoustic emission parameters are investigated.Second,the damage step condition is determined using a classification model with an acoustic emission data set acquired from uniaxial compressive strength experiments.Finally,a new damage detection and evaluation method for pile foundations is proposed.This new method is capable of continuously detecting and evaluating the damage of pile foundations in service.

Reference gene validation for quantification of gene expression during final oocyte maturation induced by diethylstilbestrol and di-(2-ethylhexyl)-phthalate in common carp

Final oocyte maturation is the key step to successful spawning and fertilization.Quantitative real-time PCR（q PCR） is the technique of election to quantify the abundance of functional genes in such study. Reference gene is essential for correct interpretation of q PCR data. However, an ideal universal reference gene that is stable under all experimental circumstances has not been described. Researchers should validate their reference genes while performing q PCR analysis. The expression of 6 candidate reference genes： 18 s r RNA,28 s r RNA, Cathepsin Z, Elongation factor 1-α, Glyceraldehyde-3-phosphate dehydrogenase andβ-actin were investigated during final oocyte maturation induced by different compounds（DES and DEHP） in common carp（Cyprinus carpio）. Four softwares（Bestkeeper, ge Norm,Norm Finder and Ref Finder） were used to screen the most stable gene in order to evaluate their expression stability. The results revealed that EF1α was highly stable expressed when final oocyte maturation was induced by DES, while gapdh was the most stable gene when final oocyte maturation was induced by DEHP. Stable expressed reference gene selection is critical for all q PCR analysis to get accurate target gene m RNA expression information.

Harnessing the soil:reshaping the tumor microenvironment towards an antitumor immune state by low-dosemetformin

Metformin,a biguanide derivate,has been in use as an anti-diabetic agent for over 60 years and has been widely accepted as first-line therapy for the management of type Ⅱ diabetes.Interestingly,the treatment of type Ⅱ diabetes with metformin is associated with reduced risk and improved prognosis for many types of cancers[1].This observation has led to an explosion of interest in the potential application of metformin for cancer chemopreventive and direct antitumor effects,but also more recently for potential immunomodulatory activity.