High prestress truss cable support principle and its application in large cross section coal roadway

With the enlarge of cross section of roadway, the radius of plastic area and broken area increase, and the tensile stress and shear stress distributing in roof coal-rock layers relevantly increase, which induce support effect not obvious for ordinary bolt（cable）. While bounding point and support structure of the truss cable is in vertex angle of roadway, and supplies coal-rock layers in bounding area with the horizontal and vertical pressure, so it settles the support problems in large cross section coal roadway. From the point of view of mechanics, gave emphasis on the invalid mechanics of ordinary bolt （cable） in large cross section coal roadway and supported mechanics of prestress truss cable. The author successfully used this technique in Wuyang Mine, and had the huge economic efficiency and the social benefit.

Negative Poisson's ratio and peripheral strain of an NPR anchor cable

Materials with a negative Poisson’s ratio effect perform significantly better than traditional materials for rock mass impact resistance,shear resistance,and energy absorption.Based on these advantages,a negative Poisson’s ratio anchor cable(NPR anchor cable)with high elongation and constant resistance was developed and successfully applied in the field of mine disaster control.However,theoretical and experimental research on the negative Poisson’s ratio effect and peripheral strain characteristics of NPR anchor cables is currently incomplete.This study used several theories and methods,such as static tensile,peripheral strain measurement,and static negative Poisson’s ratio measurement,to investigate the radial deformation law of an NPR anchor cable and the negative Poisson’s ratio characteristics.Experimental results elucidated constant resistance changes in an NPR anchor cable during operation,the motion of the constant resistance body in the constant resistance sleeve,and the deformation law of the constant resistance sleeve.Negative Poisson’s ratio characteristics of the NPR anchor cable and its superior energy absorption characteristics were verified and it provided a theoretical and experimental basis for energy absorption mechanisms of an NPR anchor cable.

基于S-CDMA技术CableModem的应用

在进行 Ｉｎｔｅｒｎｅｔ 接入方式对比的基础上，介绍了 Ｈ Ｆ Ｃ 结构 Ｃ Ａ Ｔ Ｖ 网对高速数据传输的适应性，并结合 Ｈ Ｆ Ｃ 网和 Ｓ－ Ｃ Ｄ Ｍ Ａ 技术的特点，提出了基于 Ｓ－ Ｃ Ｄ Ｍ Ａ 技术 Ｃａｂｌｅ Ｍｏｄｅｍ 应用的可行性。

Model test of negative Poisson’s ratio cable for supporting super-largespan tunnel using excavation compensation method

In recent years,there is a scenario in urban tunnel constructions to build super-large-span tunnels for traffic diversion and route optimization purposes.However,the increased size makes tunnel support more difficult.Unfortunately,there are few studies on the failure and support mechanism of the surrounding rocks in the excavation of supported tunnel,while most model tests of super-large-span tunnels focus on the failure characteristics of surrounding rocks in tunnel excavation without supports.Based on excavation compensation method(ECM),model tests of a super-large-span tunnel excavation by different anchor cable support methods in the initial support stage were carried out.The results indicate that during excavation of super-large-span tunnel,the stress and displacement of the shallow surrounding rocks decrease,following a step-shape pattern,and the tunnel failure is mainly concentrated on the vault and spandrel areas.Compared with conventional anchor cable supports,the NPR(negative Poisson’s ratio)anchor cable support is more suitable for the initial support stage of the super-large-span tunnels.The tunnel support theory,model test materials,methods,and the results obtained in this study could provide references for study of similar super-large-span tunnels。

Forward modeling of ocean-bottom cable data and wave-mode separation in fluid–solid elastic media with irregular seabed

In marine seismic exploration, ocean-bottom cable techniques accurately record the multicomponent seismic wavefield; however, the seismic wave propagation in fluid–solid media cannot be simulated by a single wave equation. In addition, when the seabed interface is irregular, traditional finite-difference schemes cannot simulate the seismic wave propagation across the irregular seabed interface. Therefore, an acoustic–elastic forward modeling and vector-based P-and S-wave separation method is proposed. In this method, we divide the fluid–solid elastic media with irregular interface into orthogonal grids and map the irregular interface in the Cartesian coordinates system into a horizontal interface in the curvilinear coordinates system of the computational domain using coordinates transformation. The acoustic and elastic wave equations in the curvilinear coordinates system are applied to the fluid and solid medium, respectively. At the irregular interface, the two equations are combined into an acoustic–elastic equation in the curvilinear coordinates system. We next introduce a full staggered-grid scheme to improve the stability of the numerical simulation. Thus, separate P-and S-wave equations in the curvilinear coordinates system are derived to realize the P-and S-wave separation method.

A Protection Method of VSC-HVDC Cables Based on Generalized S-Transform

Generalized S-transform is a time-frequency analysis method which has higher resolution than S-transform. It can precisely extract the time-amplitude characteristics of different frequency components in the signal. In this paper, a novel protection method for VSC-HVDC (Voltage source converter based high voltage DC) based on Generalized S-transform is proposed. Firstly, extracting frequency component of fault current by Generalized S-transform and using mutation point of high frequency to determine the fault time. Secondly, using the zero-frequency component of fault current to eliminate disturbances. Finally, the polarity of sudden change currents in the two terminals is employed to discriminate the internal and external faults. Simulations in PSCAD/EMTDC and MATLAB show that the proposed method can distinguish faults accurately and effectively.

应用Cable Modem技术创建天津大学宽带网

本文讨论了两种宽带接入技术，ＡＤＳＬ技术和Ｃａｂｌｅ Ｍｏｄｅｍ技术，着重介绍了Ｃａｂｌｅ Ｍｏｄｅｍ的第二代调制技术Ｓ－ＣＤＭＡ；并以天津大学宽带网为例，介绍了利用 Ｃａｂｌｅ Ｍｏｄｅｍ技术改建现有 ＣＡＷ网，构建高速宽带综合信息网的设计与实现。

对Cable Modem宽带接入应用与维护的探讨

近两三年来,随着有线电视城域网宽带双向HFC升级改造进程的加快,其上行通道的应用进入了实际的应用阶段。Cable Modem的接入方式不仅为用户提供了Internet高速接入的另一种选择,同时基于DOCSIS1.1的话音业务的开展也成为了可能。本文介绍了S-CDMA与DOCSIS两种系统CableModem的工作原理以及网络改造对上行通道的改善。并根据实际的应用维护,结合实例作一些探讨。

HFC及Cable Modem在有线电视中的发展

HFC是有线电视的骨干网 ,CableModem将是最有潜力的HFC终端接入设备 ,它是利用HFC调制技术 ,通过有线电视网进行高速数据接入的家用设备。

Comparison of Sexual Function in Primiparous Women Pre-Pregnancy and Postpartum: Difference of the Sexual Function after the Normal Vaginal Delivery and the Cesarean Section

Introduction: Sexual function is undoubtedly an important dimension of adult life. Due to all the conflicting results with regard to sexual function after the normal vaginal delivery (NVD) or the Cesarean Section (CS), in the present study, we aimed to compare the sexual function in women pre-pregnancy and postpartum and also after the NVD and CS. Materials and Methods: In this cohort study, two groups of healthy women, with antenatal normal pregnancies, who underwent NVD (n = 90) and CS (n = 113), were prospectively studied. The sexual function of the participants was assessed through a Female Sexual Function Index (FSFI) questionnaire in two stages: once before pregnancy and then within 3 to 6 months after delivery, which lasted from June 2011 to September 2012. The data were analyzed by descriptive and inferential statistics. Data were analyzed using chi-square test, Mann-Whitney test, and T Test. Results: Based on the data gathered from 206 women who completed the FSFI questionnaire in two stages, the mean (±SD) self-reported timing of the resumption of sexual activity was 8.9 ± 1.3. There was no significant statistical difference found between the two groups by timing of the resumption of sexual activity in NVD and CS groups. There was also no statistically significant difference found in the overall sexual function scores between the two groups (NVD vs. CS). The average score for female sexual function in desire, arousal, orgasm, and satisfaction within 3 to 6 months after delivery was significantly lower than that of their pre-pregnancy period (p < 0.004). The mean coitus in postpartum period was 1.84 ± 1.20 per week. Conclusion: Based on the findings of this study, there was no significant relationship between the mode of delivery and changes in sexual function. Therefore, it can be claimed that CS is not preferred to NVD with regard to preserving normal sexual functioning.

The Rate of Caesarean Sections in Burkina Faso’s Regional and University Hospitals According to the Classification System of Robson’s Ten Groups

Background: Quality assurance in labor and delivery is needed. The method must be simple and consistent, and be of universal value. The 10-Group Classification System is a simple method providing a common starting point for further detailed analysis within which all perinatal events and outcomes can be measured and compared. Objective: The purpose of this study was to analyze cesarean section (CS) rates using the classification system of Robson’s ten groups and to identify the main contributors to the overall CS rate in Burkina Faso’s regional and university hospitals. Materials and Method: A cross-sectional study with retrospective collection was carried out. All women who gave birth between July 1, 2017 and June 30, 2018, in the Regional Hospital Centres (RHC) and University Hospital Centres (UHC) of Burkina Faso were classified according to the Robson ten-group method. The overall CS rates and in each Robson group were calculated, as well as the contribution of each group to the overall CS rate. Results: The CS rate was 26.5% (8543 out of 32,240 deliveries) during the study period. nulliparous women with single term pregnancy in cephalic presentation during spontaneous labour (group 1), multiparous women with single pregnancy in cephalic presentation, gestational age ≥37SA, spontaneous labour (group 3) and multiparous women with previous CS (group 5) were the main contributors (67.7%) to the overall CS rate. In addition, we observed a variation in CS rates between different hospitals, especially among women with full-term pregnancies in cephalic presentation without previous CS (groups 1 to 4), showing large differences in emergency obstetric and neonatal care across the country. Conclusions: Women in groups 1, 3 and 5 were the most important contributors to the overall CS rate in Burkina Faso. It appears that efforts to reduce the overall rate of CS should focus on vaginal delivery on the scarred uterus, reduction of CS rates in nulliparous women with full-term pregnancy in cephalic presentation (groups 1) and proper monitoring of multiparous women with full-term pregnancy in spontaneous labour (group 3).

Quality of Caesarean Sections in Rural Sub-Saharan Africa: A Prospective Study in Cameroon

Introduction: Caesarean section (CS) is a major reproductive health intervention to improve maternal and foetal outcomes if appropriately performed. This study aimed to assess the quality of Caesarean sections (CS) in a rural setting in Cameroon. Materials and Methods: A prospective study conducted in 3 hospitals from February 1st 2020 to April 30th 2020. One hundred and twenty women who had a CS were included. Data were grouped into 5 categories: 1) Sociodemographic and obstetrical characteristics, 2) Geographic and financial access, 3) Diagnostic procedures, 4) Operative parameters and 5) Post-operative parameters. The Dujardin’s model and context-relevant criteria served to construct the quality score. The scale was 0 - 20 and scores ≤ 15 were considered as unacceptable quality while those >15 were considered as acceptable quality CS. Logistic regressions permitted to measure associations. Results: There were 538 deliveries and 120 (22.3%) CS. The mean (SD) gestational age was 38.7 (2.6) weeks with extremes of 31 and 43 weeks. Group 5 of the Robson’s classification was predominant (35.0%). Motorbikes were the mode of transport to the maternity for 72.5% (87/120) of women. No referral was made by ambulance. Only 44 (36.7%) women had paid the full cost of the CS prior to surgery. In addition, 26 (21.6%) women had a complete clinical examination on admission. The surgical team was not complete (<6 staffs) in 56 (43.3%) cases. Anaesthesia was done by nurses in all cases. CS was done by a general practitioner and by nurses in 86 (71.7%) and 14 (11.7%) cases respectively. Overall, mean (SD) quality score (QS) was 16.33 (1.60). Sixty six of the 120 (55.3%) caesarean sections had unacceptable quality CS. Mean (SD) QS was significantly higher in faith-based hospitals than in public hospitals (18.00 (0.91) versus 15.59 (1.24);P < 0.001). Immediate postoperative clinical monitoring was effective only in 66 (55%) of cases. Apgar score was below 7 over 10 in 17 (14.2%) cases of which 6 freshes still births. No maternal death was recorded and maternal complications were recorded in 14 (11.7%) cases. Conclusion: The quality of CS is generally poor in rural settings in West-Cameroon. The quantity and quality of staffs required for Caesarean sections in the hospitals are sometimes insufficient. The poor quality of CS in this region could be addressed using the faith-based hospitals: St Vincent de Paul’s Hospital as a model.

A Comparison between Supra-Scarpa’s Fascia Abdominoplasty and Traditional Abdominoplasty: Effect of Caesarian Section

Background: Abdominoplasty is still among the most popular surgeries in the world of cosmetic surgery, as many modifications have been implemented on this surgery to improve aesthetics and reduce the ratio of complication, especially seroma. Also, the duration to drain removal increases the risk of infection, and this can be avoided by preserving the Scarpa’s fascia. Methods: The study was performed from January 2018 to December 2020. The patients were divided into two groups: group A with patients who were performed in Supra-Scarpa’s fascia abdominoplasty, and group B who were performed in traditional abdominoplasty;then group A was divided into two subgroups (A1 with caesarean history and A2 with no caesarean history) that differ in caesarean history or not, while a comparison was done between the groups regarding early outcomes. Results: A total of 40 full abdominoplasties were preformed (group A, 19 patients;group B, 21 patients);then group A was divided into two subgroups (group A1, 13 patients;A2, 6 patients);we found that the time until drain removal and its drain output in group A is less with a statistical significance, and the seroma was less to happen in group A with no statistical significance. However, the operative time in group A is higher with statistical significance. In the subgroups A1 and A2, there was no statistically significant difference in the results. Conclusion: Preservation of the Scarpa’s fascia reduces the time until drain removal, total drain output and the occurrence of seroma and the caesarean scar doesn’t affect the efficacy of preserving the Scarpa’s fascia.

Cesarean Sections according to the Robson’s Classification in Two University Hospitals of Yaoundé: Indications and Maternofetal Outcome

Introduction: Cesarean section is a surgical intervention which consists in the extraction of a fetus from the uterus after its incision. The rate of cesarean section varies depending on the country and the health facility. For this reason, in 2015, the World Health Organization (WHO) recommended the use of Robson’s classification to evaluate the practice of cesarean sections in order to identify the groups of women who had abnormally high rates. The objective of our study was to evaluate cesarean sections using the Robson’s classification in CHRACERH and in the Yaoundé Central Hospital (YCH). Methodology: We carried out a retrospective cross sectional and descriptive study in two (02) university hospitals in Yaoundé which took place from December 2017 to May 2018. We included in our study all women who gave birth over a period of two (02) years from January 2016 to December 2017 in these two health facilities. Our sampling was exhaustive over the study period. The parturients’ information was collected using an anonymous and pretested questionnaire. The Robson’s group of every parturient was determined. Descriptive parameters like mean and proportions were calculated. We compared the rates and indications of cesarean sections between the both hospitals using Chi2 test. Results: Out of 330 deliveries realized in CHRACERH, we had 90 cesarean sections;hence, a rate of 27.2%. Out of 1863 deliveries carried out at the YCH, 462 were by cesarean section, hence a rate of 24.8%. The women who belonged to groups 1, 3 and 5 contributed to the highest rates of cesarean sections in both hospitals: in CHRACERH, group 5 (31.1%), group 3 (20%) and group 1 (15.6%), at YCH: group 3 (22.5%), group 1 (21.6%) and group 5 (17.3%). The indications of the cesarean sections varied depending on the Robson’s group and the hospital, the principal indication in group 1 was acute fetal distress (28.6%) in CHRACERH and cephalopelvic disproportion (36.7%) at YCH. Cephalopelvic disproportion was the predominant indication in groups 3 of CHRACERH (44.4%) and YCH (39.2%). In groups 5, CHRACERH and of YCH, a scarred uterus was the principal indication for the cesarean section at 82.4% and 78.4% respectively. At CHRACERH, the maternofetal complications were more frequent in groups 1 and 2 at the YCH, this was the case mostly in groups 1 and 3. Conclusion: The Robson’s classification is an adequate tool for the evaluation and comparison of the rates of cesarean sections. The rates of cesarean section in CHRACERH (27.2%) and at YCH (24.8%) were higher than the rates recommended by WHO. Robson’s groups 1, 3 and 5 were identified as the groups most at risk for cesarean sections in the both hospitals.

基于BFGS算法的铁路区间老化电缆故障检测仿真

信号区间电缆数量众多,分布范围广,且存在噪声干扰,使得检测难度加大。为了尽量避免老化电缆所带来的不良影响,提出基于BFGS算法的铁路区间老化电缆故障检测方法。通过高斯滤波的方式对采集的电缆故障信号实施去噪处理,避免噪声干扰,利用S变换实现对去噪后的老化电缆故障特征进行提取,将提取特征输入值BFGS算法中展开计算,以此达到故障检测的目的。经实验验证,所提方法抗噪声干扰能力较强,利用该方法获取的铁路信号区间老化电缆故障检测效果较好。

Unit 1 What’s the m atter?Section B 2a—2e教学设计及评析

[本课选自人教版义务教育课程标准实验教科书《英语》(新目标)八年级下册。]一、教材内容与分析本单元话题是健康与急救(Health and first aid).Section B是Section A主题的继续与延伸,由Section A侧重谈论疾病及不适转向对事故伤害、急救(first aid)的讨论;语言上,巩固Section A所学重点语言内容、词汇及表达,突出对步骤顺序的表达;技能上,侧重综合性的听、读、写的训练,尤其突出阅读.

Tomography for Q of the Eastern Section of the Tianshan Area from High-frequency Attenuation of S-wave

Based on the waveform data of 5,076 local earthquakes recorded at 25 stations in Xinjiang during the period from 2009 to 2014 and the observation reports provided by the Xinjiang Digital Seismic Network,a data set of 19,140 attenuation factors t*is obtained by fitting the high-frequency attenuation of S-wave spectra with a genetic algorithm. The spatial distribution of Q_S is determined by inverting the t*data with seismic tomography. The results show that the average Q0 in eastern Tianshan is 520,and there is a significant correlation between the Q_S value distribution or attenuation characteristics it disclosed and the surface structure of the study area. The Q_S value is lower in the intersection area of the mountain basin which is located on the north and south sides of the Tianshan Mountains,and the high Q_S distribution is more concentrated inside the Tianshan orogenic belt. The M≥6. 0 earthquakes have been basically located in the Low-Q_S region since 1900. 24 high heat flow points in eastern Tianshan are located at the north and south of Tianshan Mountains where low Q_S exists,indicating a negative correlation. In addition,there is a positive correlation between the velocity structure and the attenuation structure in the study area,which reflects the consistency of the 2-D attenuation structure with the velocity structure and the two-dimensional density structure.

Composition and Assemblage Characteristics of Magnetic Minerals in Layer S_(5-1) of Xifeng and Duanjiapo Sections

Relatively strongly magnetic fine components (<30μm, XS-4J and DS-4J) which are most environmentally sensitive were separated from layer S-{5-1} in the Xifeng and Duanjiapo loess sections and analyzed by MPV-3 for their morphometric characteristics and reflectance, SEM-ESD for their element contents and XRD for their mineral phases, respectively. The results showed that minerals in both samples are dominated by detrial Fe-Ti oxides of aeolian origin. In sample XS-4J the reflectance and iron contents of magnetic minerals are usually high. In addition to magnetite (Fe-3O-4), maghemite (γFe-2O-3) and hematite (Fe-2O-3), some Fe-high oxide ({72.25 wt%}-{86.67 wt%}), ilmenite (FeTiO-3), and magnetite-ulvspinel were also detected. In sample DS-4J obvious negative linear correlations were found between Ti and Fe, and the contents of Mn, Si, Al and Ca are usually high and the minerals are dominated by magnetite (maghemite), goethite (FeOOH) and limonite (containing Si and OH). In addition, the signs of corrosion of magnetic minerals and newly crystallized magnetite (maghemite) were recognized. Differences in the composition and assemblage characteristics of magnetite minerals between XS and DS reflect significant differences in source rocks and preserving conditions.

Unit 7 It’s raining! Section B(2a-2c)阅读课教学设计与反思

授课对象：初二学生指导老师：原江西省教育厅教学教材研究室谭少虞江西省南昌市教科所肖君江西省南昌市东湖区教研中心高友明一、课例背景该课例是笔者参加2016年“第十三届中学骨干英语教师新课程教学高级研修班”教学成果评选活动的参赛课例,获初中组一等奖。

级间分离S形分离钢索高速分离敏感因素分析

级间分离S形分离钢索结构复杂,高速分离过程涉及大变形、复杂非线性接触等问题,其动态变形及力学特性分析是工程设计的难点之一。基于Abaqus建立S形分离钢索动态分离仿真模型,分析了S形分离钢索高速分离动态变形过程及力学特性,并通过地面试验进一步验证建模方法的正确性。研究了S形分离钢索长度、截面直径、拖尾长度、分离速度等多种敏感因素的影响,对工程实际具有一定的指导意义。