气相色谱仪硬件故障分析与维修

文章通过对气相色谱仪结构和工作原理的介绍,根据工作中遇到的故障现象,分别探讨了其故障分析及处理,供从事气相色谱仪维修和使用的人员参考。     

气相色谱仪在石化行业应用中的常见故障与处理措施分析

石化行业领域,气相色谱仪的较为广泛,如炼厂产品检测、石化产品分析和油气田生产等方面均有着重要影响.气相色谱仪在石化行业应用中,较易出现部分常见故障,对石化行业也产生一定的影响.随着石化行业的快速发展,对气相色谱仪的应用又有着更为严格的标准要求,务必重视对常见故障的深入分析研究,制定科学合理的处理措施,确保气相色谱仪可以...     

GC4600气相色谱仪常见故障检修

通过对GC4600气相色谱仪实例维修,得出这种仪器的故障特点以及处理方法。     

气相色谱检测器污染的分析与处理

举例分析了气相色谱仪检测器污染的原因及处理办法。     

6820气相色谱色谱峰问题处理

6820气相色谱仪在分析过程中时常会遇到色谱峰出现分离度降低、峰宽增加、基线波动和漂移、峰高或峰面积变化等技术问题,这些问题直接影响着数据分析的及时性和准确性。那么6820气相色谱仪色谱峰问题处理则成为我们急需解决的问题。     

CP3800气相色谱仪的使用和维护

描述CP3800气相色谱仪的使用规范和维护措施,以及使用过程中容易出现的故障的处理方法。     

关于2305气相色谱仪故障排除的几点经验

本文就2305气相色谱仪及使用过程中所出现的一些问题,提出了具体的处理方法和应急措施。     

硫化学发光检测器氢中毒的研究

气相色谱仪在天然气领域中发挥着重要作用,在长期的使用过程中,气相色谱仪硫化学发光检测器过高的H2/O2流速比会使其发生氢中毒现象。氢中毒会导致检测器的响应值大幅降低并影响到检测数据的准确度。本文通过对气相色谱仪的原理和双等离子体控制器的结构分析,并对双等离子体燃烧器陶瓷管进行高温活化处理,通过处理前后的实验数据对比,得出高温活化陶瓷管可在一定时间内解决双等离子燃烧器陶瓷管的氢中毒现象,此方法已在中亚管输天然气的离线检测中得到应用,并取得良好效果。     

气相色谱仪在使用过程中的故障分析与处理措施

随着高新技术的日益发展,我们当代的科技水平等也得到了充分的发展,在对于天然气的检验方面,我们也有了很大的进步,尤其是气相色谱仪的使用,它能够更加精确的检测出天然气的组成成分。但是,在日常的使用中,由于使用方法不当、保护保养的手法不当等原因,常常会导致气相色谱仪出现各种各样的问题。下面,我将从多个方面就气相色谱仪可能出现的故障和问题,提出一些相对应的处理措施。     

如何保证在线气相色谱仪的分析准确性

如何保护在线气相色谱仪能够得到准确的分析数据是个十分重要的问题,分析仪的温度、载气的流速和纯度、样品的气化程序、标准气体的混合均匀程度以及色谱处理参数等因素都将对此产生影响。结合聚丙烯生产过程中的丙烯中氢气含量在线气相色谱仪,对这一问题进行比较全面的讨论。     

Involvement of miR-20a in Promoting Gastric Cancer Progression by Targeting Early Growth Response 2 (EGR2)

Gastric cancer (GC) is one of the most common cancers, with high incidences in East Asia. microRNAs (miRNAs) play essential roles in the carcinogenesis of GC. miR-20a was elevated in GC, while the potential function of miR-20a was poorly understood. miR-20a expression was examined in GC tissues and cell lines. The effects of miR-20a on the growth, migration, invasion, and chemoresistance of GC cells were examined. Luciferase reporter assay and Western blot were used to screen the target of miR-20a. miR-20a was increased in GC tissues and cell lines. miR-20a promoted the growth, migration and invasion of GC cells, enhanced the chemoresistance of GC cells to cisplatin and docetaxel. Luciferase activity and Western blot confirmed that miR-20a negatively regulated EGR2 expression. Overexpression of EGR2 significantly attenuated the oncogenic effect of miR-20a. miR-20a was involved in the carcinogenesis of GC through modulation of the EGR2 signaling pathway.     

甲醇在聚苯胺载铂电极上的电催化氧化

用循环伏安法在玻碳电极上电聚合导电高分子聚苯胺用于附载Pt,提高了Pt的分散度。发现甲醇在Pt／PAN／GC电极和Pt／GC电极上均能自发解离出强吸附中间体CO,证实聚苯胺膜的存在有利于提高电极对甲醇的电催化氧化活性,CO在Pt／PAN／GC电极上的氧化峰电流明显高于Pt／GC电极。通过比较甲醇的电催化氧化活性可知,Pt/PAN／GC电极催化氧化甲醇的峰电流为58．68mA/cm^2和50．00mA／cm^2,是Pt／GC电极氧化峰电流的1．6倍和1．7倍。     

Hyaluronic Acid as a Carrier Supports the Effects of Glucocorticoids and Diminishes the Cytotoxic Effects of Local Anesthetics in Human Articular Chondrocytes In Vitro

The current study aimed to investigate the cytotoxicity of co-administrating local anesthetics (LA) with glucocorticoids (GC) and hyaluronic acid (HA) in vitro. Human articular cartilage was obtained from five patients undergoing total knee arthroplasty. Chondrocytes were isolated, expanded, and seeded in 24-well plates for experimental testing. LA (lidocaine, bupivacaine, ropivacaine) were administered separately and co-administered with the following substances: GC, HA, and GC/HA. Viability was confirmed by microscopic images, flow cytometry, metabolic activity, and live/dead assay. The addition of HA and GC/HA resulted in enhanced attachment and branched appearance of the chondrocytes compared to LA and LA/GC. Metabolic activity was better in all LA co-administered with HA and GC/HA than with GC and only LA. Flow cytometry revealed the lowest cell viability in lidocaine and the highest cell viability in ropivacaine. This finding was also confirmed by live/dead assay. In conclusion, HA supports the effect of GC and reduces chondrotoxic effects of LA in vitro. Thereby, the co-administration of HA to LA and GC offers an alternative less chondrotoxic approach for treating patients with symptomatic osteoarthritis of the knee.     

气相色谱法在环境分析中的应用

气相色谱是一种新型、高效分离、分析技术。文章在系统地介绍气相色谱的发展、原理、结构、应用范围、特点的基础上,阐述了近年来气相色谱技术在环境分析中的应用,并预测了今后的发展趋势。     

色谱法分析石油中芳烃的研究进展

准确分析出石油中芳烃的种类和含量,是石油评价的一个重要指标。本文综述了色谱分析方法包括GC,GC×GC,HPLC,GC-MS等在石油中芳烃测定的应用进展。     

Pt/PAn/GC电极的制备及对甲酸电催化氧化性能的研究

利用循环伏安法电聚合导电高分子聚苯胺，并制备了Pt／PAn／GC电极和Pt／GC电极，优化了苯胺在玻碳电极上的聚合条件，用在H2SO4中的循环伏安曲线对其进行了表征，Pt／PAn／GC电极的制备提高了Pt的分散度，增加了催化剂Pt的利用率。实验结果表明Pt／PAn／GC电极对甲酸电氧化的催化活性明显高于Pt／GC电极和Pt电极，正向扫描和反向扫描时对应的氧化峰电位分别是0．68V、0．45V。峰电流为54．23mA／cm^2和84．23mA／cm^2，为Pt／GC电极的修饰电极1．7倍和1．9倍，为Pt片电极的3．8倍和4．9倍，有效地提高了铂微粒的催化活性，并得到聚合苯胺的最佳条件为扫描速度50mV／s、扫描上限1．2V。     

Activated red mud-supported Zn/Al oxide catalysts for catalytic conversion of glycerol to glycerol carbonate: FTIR analysis

Catalytic conversion to glycerol carbonate (GC) from glycerol and urea was investigated with Zn/Al oxide catalysts supported by activated red mud (ARM), a waste material. Compared to an unsupported catalyst, ARM-supported Zn/Al oxide catalysts exhibited higher GC yields. ARM-supported Zn/Al oxide catalysts showed a volcano curve for the GC yield as a function of the Zn/Al loading. FTIR analysis revealed the ARM-supported Zn/Al oxide catalysts to be more selective, resulting in higher GC yield. The balance of active sites from ARM and Zn/Al oxide was related to rates of each reaction step in GC synthesis, which eventually influenced on the selectivity and yield of GC.     

甲醛在nano-Pt/GC电极上的电催化氧化研究

应用循环伏安法制备了nano-Pt/GC电极,并用SEM和电极在H2SO4中的循环伏安曲线对其进行了表征。结果表明,该方法制备的电极表面铂粒子分布较为均匀,粒径大小约为140nm,电极具有较大比表面积。电化学实验表明,该电极对甲醛电氧化的催化活性明显好于铂片电极。修饰电极的催化活性与铂粒子的沉积条件有关,铂微粒在电极表面的最佳沉积条件为循环次数100次和沉积速度5mV/s。     

Role of miR-191/425 Cluster in Tumorigenesis and Diagnosis of Gastric Cancer

Gastric cancer (GC) is among the most frequent types of cancer worldwide. Therefore, understanding the biology of GC tumorigenesis is important for appropriate diagnosis and patient surveillance. The miR-191/425 cluster has been reported to be overexpressed in various human cancers, but the tumorigenic role and clinical significance of miR-191/425 overexpression in gastric carcinogenesis is currently undefined. In this study, the expression of miR-191 and miR-425 in GC tissue and serum was assessed, and the relationship between miRNA expression and clinicopathological data was analyzed. We found that miR-191 and miR-425 were both significantly increased in human GC tissues relative to adjacent normal controls. In addition, miR-191 levels correlated with GC tumor stage and metastatic state. Furthermore, the level of serum miR-191 was significantly higher in the GC group than in the control group when using serum miR-16 as an endogenous control. Finally, inhibition of miR-191 or miR-425 in the GC cell lines HGC-27 not only reduced cell proliferation and cell cycle progression but also impaired cell migration and invasion. Taken together, our results revealed the oncogenic roles of miR-191 and miR-425 in gastric carcinogenesis, and indicated the potential use of serum miR-191 as a novel and stable biomarker for GC diagnosis.     

烟用香精的全二维气相色谱-飞行时间质谱定性分析

针对在一维色谱上分离峰太少或色谱图中有明显重叠峰的烟用香精,采用全二维气相色谱-飞行时间质谱（GC×GC-TOFMS）对烟用香精进行了定性分析,优化分析条件,并与一维色谱分析结果进行比较。最后,比较了不同分析结果所得化学成分和品吸结果之间的对应关系。结果表明,GC×GC-TOFMS比一维气相色谱/质谱（GC/MS）具有更强的分离能力,可定性的组分明显多于一维GC/MS,并且更符合该香精的评吸结果。这种分析方法有利于更全面地认识香精的化学成分,更准确地认识香精的组成与功能之间的关系。为增强加香配方研究的科学性、提高调香工作的效率提供有力的支持。