浅析循环机运转过程中的故障及改造措施

循环机是小氮肥生产必不可少的运转设备,针对循环机运转过程中出现的故障进行了分析,对故障发生、发展的过程,故障发生的原因进行了研究,提出了控制故障的措施。     

PTA氧化反应器搅拌器故障分析及对策

洛阳石化PTA装置氧化反应器搅拌器故障频繁,严重影响了装置的安稳运行。本文针对洛阳PTA氧化反应器多年来因搅拌器故障导致装置意外停车的故障进行了履历调查,对典型的故障进行了分析,提出了相应的故障对策。     

用于化工过程的SDG故障分析方法

基于符号有向图（signed directed graph,SDG）的化工过程模型可以表征过程故障与故障源之间的因果关系,SDG故障分析方法通过有向图定性推理技术实现故障诊断。本文简要介绍了SDG故障分析的基本概念,并对Iri算法^[1]中故障源的搜索步骤提出了部分改进,并进行了实例验证。最后,利用SDG故障诊断方法对某化工厂的氯气泄漏事故的故障传播进行了分析研究。     

DCS系统与PLC系统通讯故障分析

本文对DCS系统与PLC系统进行了介绍,并且以某企业出现的DCS系统与PLC系统通讯故障为例,对DCS系统与PLC系统通讯故障的检测、故障排除以及故障原因分析进行了探讨,并且提出了预防该故障发生的策略。     

煤矿带式输送机常见故障问题与处理探究

带式输送机是煤矿生产中一种常见的设备,用于提高生产效率,具有诸多的优势,针对带式输送机使用过程中的故障问题要进行早期防范治理,保证矿山生产安全性和高效性。本文对带式输送机的特点展开了讨论,分析了常见的故障和处理措施。对跑偏故障、打滑故障、断带故障、断裂故障的原因和具体的处理方法进行了讨论,用于煤矿生产活动的指导和管理。     

江陵换流站GIS断路器操作机构故障处理

江陵换流站500kV交流场采用GIS设备,在运行过程中,GIS断路器操作机构多次出现液压油渗漏、机械传动故障、分闸线圈故障等故障。对江陵换流站GIS断路器操作机构出现的故障进行了描述,并对处理方法进行了详细介绍。     

洛阳PTA薄膜蒸发器故障及对策

洛阳石化PTA装置薄膜蒸发器故障频繁,影响了装置的安稳平稳运行。针对洛阳PTA装置多年来因薄膜蒸发器故障频繁导致溶剂回收系统波动进行了履历调查,对典型的故障进行了分析,提出了相应的故障对策。     

基于FMEA和ALARP的南海东部模块钻机顶驱系统风险分析

顶驱系统是新型模块钻机的关键装备,其安全可靠的服役直接关系到模块钻机的安全稳定作业。采用FMEA对模块钻机顶驱系统的潜在故障模式进行了分析,对各故障模式的风险数进行了评估,其中干涉故障和渗油故障的风险优先数最高;基于ALARP原则,确定了顶驱系统潜在故障模式的风险数划分标准,并对各故障模式进行了风险等级分类,其中高风险故障占32%,必须立即采取措施整改或降低高风险区故障模式的风险优先数。     

基于PCA固体垃圾焚烧炉的早期故障诊断

介绍了主元分析法(PCA)及其在垃圾焚烧炉故障诊断中的应用。通过分析历史数据获取主元模型,对运行数据进行在线分析,采用T2和SPE统计法对控制系统进行故障检测,并用故障贡献图对故障进行诊断。研究结果表明,PCA能有效地进行固体垃圾焚烧炉早期故障检测及诊断。     

基于模糊粗糙集和事例推理的凝汽器真空故障诊断

针对凝汽器真空故障诊断的不确定性和复杂性,提出一种基于模糊粗糙集和事例推理的凝汽器故障诊断新方法。首先,运用模糊粗糙集属性约简方法对故障特征进行约简和权重分配,不仅提取了反映故障的主要特征量,降低了特征变量之间的非线性相关性,而且避免了人的主观性对权重分配的影响。然后,在分析凝汽器真空故障特征的基础上,建立凝汽器真空故障树,以约简特征作为条件对故障树根节点进行归纳检索,有效地减少了候选事例的数量,再通过最近邻法检索故障树叶节点,对凝汽器真空故障进行智能定位。通过对汽轮机凝汽器历史故障特征数据集仿真,验证了该方法的有效性。     

燃气轮机的维护检修探讨

介绍了建峰化肥厂燃气轮机的设计维修特点,影响燃气轮机的维修和使用寿命的因素,以及如何正确确定燃气轮机的维修间隔期,为确定燃气轮机的检修内容、检修周期提供参考.     

A comparison of internal self-repair with resin injection in repair of concrete

A comparison is made between the two modes of repair of internal cracks in concrete: resin injection, which is done manually after cracking, and self-repair in which the adhesive for repair is already present in the matrix at the time the cracking occurs. The purpose of the project was to study the effect of various adhesives used for self-repair on the repair of concrete considering factors such as stress transfer capability, varying crack width, and damping. Different release modes and a similar range of adhesives with varying modulus of elasticity were used in the experiments. The purpose for varying the modulus of elasticity was to investigate the penetration ability of the adhesives. It is known that an adhesive's relative stiffness is directly related to its modulus of elasticity, and consequently, its ability to repair cracks is influenced by this factor. Finally, a comparison was made with studies undertaken by others on resin injection repair regarding stress, strain, and modulus of elasticity. Self-repair adhesives with higher modulus of elasticity (stiffer adhesives) transferred stresses well across the crack width allowing the crack to sustain as much, if not more, as the original loading as measured by specimen strength. The adhesives with lower modulus of elasticity (more flexible adhesives) also transferred the stresses.     

X-Ray Repair Cross Complementing Protein 1 in Base Excision Repair

X-ray Repair Cross Complementing protein 1 (XRCC1) acts as a scaffolding protein in the converging base excision repair (BER) and single strand break repair (SSBR) pathways. XRCC1 also interacts with itself and rapidly accumulates at sites of DNA damage. XRCC1 can thus mediate the assembly of large multiprotein DNA repair complexes as well as facilitate the recruitment of DNA repair proteins to sites of DNA damage. Moreover, XRCC1 is present in constitutive DNA repair complexes, some of which associate with the replication machinery. Because of the critical role of XRCC1 in DNA repair, its common variants Arg194Trp, Arg280His and Arg399Gln have been extensively studied. However, the prevalence of these variants varies strongly in different populations, and their functional influence on DNA repair and disease remains elusive. Here we present the current knowledge about the role of XRCC1 and its variants in BER and human disease/cancer.     

A Consensus Model of Homology-Directed Repair Initiated by CRISPR/Cas Activity

The mechanism of action of ssODN-directed gene editing has been a topic of discussion within the field of CRISPR gene editing since its inception. Multiple comparable, but distinct, pathways have been discovered for DNA repair both with and without a repair template oligonucleotide. We have previously described the ExACT pathway for oligo-driven DNA repair, which consisted of a two-step DNA synthesis-driven repair catalyzed by the simultaneous binding of the repair oligonucleotide (ssODN) upstream and downstream of the double-strand break. In order to better elucidate the mechanism of ExACT-based repair, we have challenged the assumptions of the pathway with those outlines in other similar non-ssODN-based DNA repair mechanisms. This more comprehensive iteration of the ExACT pathway better described the many different ways where DNA repair can occur in the presence of a repair oligonucleotide after CRISPR cleavage, as well as how these previously distinct pathways can overlap and lead to even more unique repair outcomes.     

国内外水性汽车修补漆发展之路

水性汽车修补漆以其绿色、环保、可持续发展的特点必将引领着汽车修补漆行业的发展趋势。文章介绍了全球和中国汽车修补漆市场动态,VOC排放相关法律法规,水性汽车修补漆的发展历史、现状,以及对水性汽车修补漆未来的展望。     

军用飞机金属构件战伤的复合材料快速修复技术研究概况

本文概述了军用飞机金属构件战伤的复合材料快速修复技术国内外的研究现状、发展趋势，分析了复合材料修复技术的优缺点以及存在的问题。     

磷酸钾镁水泥修补材料研究综述

磷酸钾镁水泥是一种通过化学键结合的新型胶凝材料,具有比传统硅酸盐水泥更优异的性能,目前已成为快速修补材料研究的热点之一。本文介绍了修补材料的研究现状,总结了磷酸钾镁水泥的制备与水化过程,详述了其工作性、力学性能、耐久性、体积稳定性和裂缝修复的研究进展,分析了当前研究存在的问题,指出了磷酸钾镁水泥发展趋势以及其在修补加固工程中的应用前景。     

Oxidative Damage in Sporadic Colorectal Cancer: Molecular Mapping of Base Excision Repair Glycosylases MUTYH and hOGG1 in Colorectal Cancer Patients

Oxidative stress, oxidative DNA damage and resulting mutations play a role in colorectal carcinogenesis. Impaired equilibrium between DNA damage formation, antioxidant status, and DNA repair capacity is responsible for the accumulation of genetic mutations and genomic instability. The lesion-specific DNA glycosylases, e.g., hOGG1 and MUTYH, initiate the repair of oxidative DNA damage. Hereditary syndromes (MUTYH-associated polyposis, NTHL1-associated tumor syndrome) with germline mutations causing a loss-of-function in base excision repair glycosylases, serve as straight forward evidence on the role of oxidative DNA damage and its repair. Altered or inhibited function of above glycosylases result in an accumulation of oxidative DNA damage and contribute to the adenoma-adenocarcinoma transition. Oxidative DNA damage, unless repaired, often gives rise G:C > T:A mutations in tumor suppressor genes and proto-oncogenes with subsequent occurrence of chromosomal copy-neutral loss of heterozygosity. For instance, G>T transversions in position c.34 of a KRAS gene serves as a pre-screening tool for MUTYH-associated polyposis diagnosis. Since sporadic colorectal cancer represents more complex and heterogenous disease, the situation is more complicated. In the present study we focused on the roles of base excision repair glycosylases (hOGG1, MUTYH) in colorectal cancer patients by investigating tumor and adjacent mucosa tissues. Although we found downregulation of both glycosylases and significantly lower expression of hOGG1 in tumor tissues, accompanied with G>T mutations in KRAS gene, oxidative DNA damage and its repair cannot solely explain the onset of sporadic colorectal cancer. In this respect, other factors (especially microenvironment) per se or in combination with oxidative DNA damage warrant further attention. Base excision repair characteristics determined in colorectal cancer tissues and their association with disease prognosis have been discussed as well.     

Histone Displacement during Nucleotide Excision Repair

Nucleotide excision repair (NER) is an important DNA repair mechanism required for cellular resistance against UV light and toxic chemicals such as those found in tobacco smoke. In living cells, NER efficiently detects and removes DNA lesions within the large nuclear macromolecular complex called chromatin. The condensed nature of chromatin inhibits many DNA metabolizing activities, including NER. In order to promote efficient repair, detection of a lesion not only has to activate the NER pathway but also chromatin remodeling. In general, such remodeling is thought on the one hand to precede NER, thus allowing repair proteins to efficiently access DNA. On the other hand, after completion of the repair, the chromatin must be returned to its previous undamaged state. Chromatin remodeling can refer to three separate but interconnected processes, histone post-translational modifications, insertion of histone variants and histone displacement (including nucleosome sliding). Here we review current knowledge, and speculate about current unknowns, regarding those chromatin remodeling activities that physically displace histones before, during and after NER.