Experimental investigation on fracturing process of marble under biaxial compression

In this study, servo-controlled biaxial compression tests were conducted on marble specimens to investigate their failure characteristics and fracturing process. The complete stress–strain curves were obtained, and the three-dimensional (3D) features of the failure surfaces were acquired by 3D laser scanning. Acoustic emission (AE) monitoring and moment tensor (MT) analysis were used in combination to better understand the fracturing mechanism of marble under biaxial compression. It was noted that a type of 3D stepwise cracking behaviour occurred on the fracturing surfaces of the examined specimens. The stress dropped multiple times, and a repeated fracturing mode corresponding to the repeated stress drops in the post-peak regime was observed. Three substages, i.e. stress stabilisation, stress decrease and stress increase, were identified for a single fracturing mode. Then quantitative and statistical analyses of the fracturing process at each substage were discussed. Based on the testing results, it was found that at the stress stabilisation substage, the proportion of mixed-mode fractures increased. At the stress decrease substage, the proportion of mixed-mode fractures decreased, and the tensile or shear fractures increased. At the stress increase substage, the proportion of mixed-mode or tensile fractures decreased, and the shear fractures increased. Finally, a conceptual model for the stepwise crack formation was proposed.     

基于Cruise的某DCT车型的性能分析

以某款配置DCT的轿车为例,简单梳理了整车动力性、经济性所需的关键参数,并运用Cruise软件搭建了DCT模型,分析了DCT的性能优劣。     

基于单片机的家用电话远程遥控装置设计

设计并实现了一种基于电话通道的家用电器遥控装置。该装置采用单片机智能控制,利用不同的提示音达到对不同操作的提示和受控方状态的信息反馈,从而使操作者能及时了解受控方信息,使产品达到交互式与智能化。经过实际测试:该装置经济、可靠,符合未来家电的智能化发展方向,具有一定的实用价值。     

基于FXIN_40MT的抢答器电路设计

基于三菱FXIN_40MT可编程控制器设计抢答器模块,使可编程控制器实训台功能更强,能完成丰富多彩且具有不同专业特色的实训项目。针对FXIN_40MT的输出点不够,采用软硬件结合的设计方案节省I／O点;针对模块电路体积的尺寸要求,采用FXIN_40MT的可编程元件特殊辅助继电器M8013编程为倒计时电路提供秒时钟信号、利用特殊辅助继电器M8011编程为超时语音报警电路提供100Hz的输入信号简化硬件电路以减小模块体积;采用顺序控制编程方法编写抢答器的指令表程序。电路具有抢答选手编号显示功能、抢答倒计时功能和答题超时语音声光报警功能．答题时间可在0～99s范围内设置,抢答器具有小于15ms分辨率。     

基于MODBUS协议的触摸屏与MCU通信实例设计

为了提高陆轨两用电动汽车的可操控性,在MODBUS协议的基础上,设计实现以单片机为例的MCU与步科触摸屏MT4523T通讯的人机交互系统,并给出了设计方法与部分软件及其流程图.通过实际验证,该系统稳定可靠,能够简便地控制电动汽车的运行与换轨动作.在一定程度上为触摸屏与带串行接口的其他MCU间的通讯提供了参考.     

M701F型燃气轮机控制系统分析

M701F燃机DCS采用DiasysNetmation,其控制主要由燃机控制系统、燃机保护系统和高级燃烧压力波动监视系统组成。本文简要介绍了M701F燃机DCS系统的构成,分别叙述了TCS、TPS和ACPFM自控制系统的作用,并对其主要控制功能进行了分析。     

多功能电话监控系统的实现

文章根据电话监控与监管的要求,设计和简化了共用串口的数据采集与数据通信电路,DTMF输出信号耦合电路和摘挂机检测与模拟摘挂机电路。通过反复的实验和分析,实现了来电号码的检测和状态检测,同时还能检测并线电话的主叫号码以及进行主叫状态的检测,上位机还可以发送控制指令拨打指定号码。本系统具有完善的功能和精简的电路结构,是一个经济、实用电话监控系统。     

大地电磁法在沪蓉国道地质勘察中的应用

大地电磁法是一种天然源电磁测深方法,具有勘探深度较大,分辨能力强,观测效率高的特点,是探测岩溶及研究地质构造和寻找隐伏断层的 有效方法。尤其在大中型隧道的前期勘探中将会发挥重要的作用。该方法与常规的同类物探方法相比,在勘探深度和分辨率均有较大的提高。介绍了大地电磁法在沪蓉国道隧道比选勘 探中的应用效果,查明了两条测线的溶洞发育情况、断层分布及其特征,为今后在隧道、桥址地质勘察中快速探测溶洞及断层等地质构造,探索了一条新途径。     

大地电磁测深远参考技术及应用效果

由于大地电磁测深勘探易受人文因素干扰,致使资料数据离差大、曲线形态畸变、可信度差。远参考技术是一种有效压制人文干扰的方法。本文阐述了远参考处理方法以及野外采集技术,分析了经远参考处理后MT资料的效果。     

A Role of DNA Methylation within the CYP17A1 Gene in the Association of Genetic and Environmental Risk Factors with Stress-Related Manifestations of Schizophrenia

As genetic and environmental influences on schizophrenia might converge on DNA methylation (DNAm) within loci which are both associated with the disease and implicated in response to environmental stress, we examined whether DNAm within CYP17A1, a hypothalamus–pituitary–adrenal axis gene which is situated within the schizophrenia risk locus 10q24.32, would mediate genetic and environmental effects on stress-related schizophrenia symptoms. DNAm within an exonic–intronic fragment of CYP17A1 was assessed in the blood of 66 schizophrenia patients and 63 controls using single-molecule real-time bisulfite sequencing. Additionally, the VNTR polymorphism of the AS3MT gene, a plausible causal variant within the 10q24.32 locus, was genotyped in extended patient and control samples (n = 700). The effects of local haplotype, VNTR and a polyenviromic risk score (PERS) on DNAm, episodic verbal memory, executive functions, depression, and suicidality of patients were assessed. Haplotype and PERS differentially influenced DNAm at four variably methylated sites identified within the fragment, with stochastic, additive, and allele-specific effects being found. An allele-specific DNAm at CpG-SNP rs3781286 mediated the relationship between the local haplotype and verbal fluency. Our findings do not confirm that the interrogated DNA fragment is a place where genetic and environmental risk factors converge to influence schizophrenia symptoms through DNAm.