Comparison of different approaches for direct coupling of solid-phase microextraction to mass spectrometry for drugs of abuse analysis in plasma

The direct coupling of solid-phase microextraction(SPME)to mass spectrometry(MS)(SPME-MS)has proven to be an effective method for the fast screening and quantitative analysis of compounds in complex matrices such as blood and plasma.In recent years,our lab has developed three novel SPME-MS techniques:SPME-microfluidic open interface-MS(SPME-MOI-MS),coated blade spray-MS(CBS-MS),and SPME-probe electrospray ionization-MS(SPME-PESI-MS).The fast and high-throughput nature of these SPME-MS technologies makes them attractive options for point-of-care analysis and anti-doping testing.However,all these three techniques utilize different SPME geometries and were tested with different MS instruments.Lack of comparative data makes it difficult to determine which of these methodologies is the best option for any given application.This work fills this gap by making a comprehensive comparison of these three technologies with different SPME devices including SPME fibers,CBS blades,and SPME-PESI probes and SPME-liquid chromatography-MS(SPME-LC-MS)for the analysis of drugs of abuse using the same MS instrument.Furthermore,for the first time,we developed different desorption chambers for MOI-MS for coupling with SPME fibers,CBS blades,and SPME-PESI probes,thus illustrating the universality of this approach.In total,eight analytical methods were developed,with the experimental data showing that all the SPME-based methods provided good analytical performance with R^(2)of linearities larger than 0.9925,accuracies between 81%and 118%,and good precision with an RSD%≤13%.

Numerical simulation of multistage induction heating of coated steel tubes in Baosteel

The electromagnetic and temperature fields in the multistage intermediate-frequency induction heating of coated steel tubes were calculated using a numerical simulation.The influence of the voltage and frequency on the parameters of power circuit and heating temperature of the steel pipe was also analyzed.The results indicate that:(1) the electromagnetic field of induction heating is concentrated between the induction coil and steel tube and dissipated more at both ends of the coil;(2) during the induction heating,the temperature difference between the outer and inner walls of the steel pipe is approximately 3040 K,and the two temperatures rapidly tend to be the same after exiting the induction heater;(3)during the natural cooling,the temperature drop of the steel tube in the low-temperature section is approximately 10 K,and that in the high-temperature section is approximately 20 K;(4)the appropriate induction heating frequency and matching capacitance should be selected,so that the temperature of the steel pipe,especially at the outer wall,meets the coating process requirements,and as to achieve a synchronous improvement of the power efficiency and heating efficiency.This study is beneficial to building a more low-consumption and high-efficiency coating line of large-diameter steel pipes in Baosteel.

Effect of thermal cycle on Ni-Cr based nanostructured thermal spray coating in boiler tubes

Ni-Cr based nanostructured feedstock powder was prepared by mechanical milling technique involving repeated welding, fracturing, and re-welding of powder particles in a planetary ball mill. The milled nanocrystalline powders were used to coat carbon steel tubes using high velocity oxygen fuel（HVOF） thermal spraying process. The characterization of the feedstock powder and HVOF coated substrates was performed using optical microscope, X-ray diffractometer（XRD）, scanning electron microscope（SEM）, high resolution transmission electron microscope（HR-TEM）, energy dispersive spectrometer（EDS） and microhardness tests. The coated and uncoated samples were subjected to different thermal cycles and characterized for their phase changes, metallurgical changes and microhardness variations. Ni-Cr nanostructured coated samples exhibited higher mechanical and metallurgical properties compared to their conventionally coated counter parts. The results showed that the nanostructured coating possessed a more uniform and denser microstructure than the conventional coating.

High-Temperature Corrosion of Protective Coatings for Boiler Tubes in Thermal Power Plants

High-temperature corrosion is a serious problem for the water-wall tubes of boilers used in thermal power plants. Oxidation, sulfidation and molten salt corrosion are main corrosion ways.Thereinto, the most severe corrosion occurs in molten salt corrosion environment. Materials rich in oxides formers, such as chromium and aluminum, are needed to resist corrosion in high-temperature and corrosive environment, but processability of such bulk alloys is very limited. High velocity electric arc spraying (HVAS) technology is adopted to produce coatings with high corrosion resistance. By comparison, NiCr (Ni-45Cr-4Ti) is recommended as a promising alloy coating for the water-wall tubes, which can even resist molten salt corrosion attack. In the study of corrosion mechanism, the modern material analysis methods, such as scanning electron microscopy (SEM), X-ray diffractometry (XRD) and energy dispersive spectrometry (EDS), are used. It is found that the corrosion resistances of NiCr and FeCrAI coatings are much better than that of 20g steel, that the NiCr coatings have the best anti-corrosion properties, and that the NiCr coatings have slightly lower pores than FeCrAI coatings.It is testified that corrosion resistance of coatings is mainly determined by chromium content, and the microstructure of a coating is as important as the chemical composition of the material. In addition, the fracture mechanisms of coatings in the cycle of heating and cooling are put forward. The difference of the thermal physical properties between coatings and base metals results in the thermal stress inside the coatings. Consequently, the coatings spall from the base metal.

The Hot Corrosion Performance of NiCr-Cr_3C_2 Cermet Coating to Boiler Tube

Three kinds of NiCr-Cr 3C 2 cermet coatings were designed and deposited by the subsonic velocity flame spraying, and their performances of hot corrosion performance were evaluated in comparison with 102G, 20G boiler tube steel, FeCrAl, NiCrTi, Ni50Cr and NiCrAlMoFe-Cr 3C 2 coatings, which are widely used at present for protection of boiler tubes. Meanwhile,the influence of sealer on the hot corrosion resistance of various coatings and the mechanisms of coating corrosion were explored.

Extended Anode Effect for Tube Inner Coating of Non-Conductive Ceramics by Pulsed Coaxial Magnetron Plasma

For uniform tube inner coating of non-conductive thin films, the double-ended coaxial magnetron pulsed plasma (DCMPP) method was investigated. In this study, coating of TiN and TiO2 was performed. It was clearly shown that the extended anode effect was strongly influenced by the electric resistance of the coated thin films on the inner surface of an insulator tube. Additionally, high frequency (100 kHz) was better for relatively high plasma density. On the other hand, in the case of titanium oxide deposition, negative ion productions drastically decrease the deposition rate and the shifting velocity of plasma main position for coated TiO2 films.

Time-course monitoring of in vitro biotransformation reaction via solid-phase microextraction-ambient mass spectrometry approaches

The solid-phase microextraction technique quantifies analytes without considerably affecting the sample composition.Herein,a proof-of-concept study was conducted to demonstrate the use of coated probe electrospray ionization(coated-PESI)and coated blade spray(CBS)as ambient mass spectrometry approaches for monitoring drug biotransformation.The ability of these methods was investigated for monitoring the dephosphorylation of a prodrug,combretastatin A4 phosphate(CA4P),into its active form,combretastatin A4(CA4),in a cell culture medium supplemented with fetal bovine serum.The CBS spot analysis was modified to achieve the same extraction efficiency as protein precipitation and obtained results in 7 min.Because coated-PESI performs extraction without consuming any samples,it is the preferred technique in the case of a limited sample volume.Although coated-PESI only extracts small quantities of analytes,it uses the desorption solvent volume of 5-10 pL,resulting in high sensitivity,thus allowing the detection of compounds after only 1 min of extraction.The biotransformation of CA4P into CA4 via phosphatases occurs within the simple matrix,and the proposed sample preparation techniques are suitable for monitoring the biotransformation.

Preparation and Anti-coking Property of SiO_2/S Coating on HP40 Tube

SiO2/S coating was prepared on the inner surface of an HP40 tube using dimethyldisulfide and tetraethylorthosilicate by atmospheric pressure chemical vapor deposition(APCVD) to alleviate catalytic coking on the inner surface of radiant tube for ethylene production in petrochemical plants.The comparative coking experiments with the coated and uncoated HP40 tubes were carried out under the same cracking conditions.SiO2/S coating was compact and had excellent anti-coking property.The coke on the coated HP40 tube was about 22% of that on the uncoated HP40 tube,and only small granular coke was deposited on the coated HP40 tube.However,the filamentous coke formed on the uncoated HP40 tube.The thermal stability of SiO2/S coating was satisfactory at cracking temperature,and the anti-coking property of SiO2/S coating was still over 60% after 3 coking and decoking cycles.

全玻璃真空太阳集热管关键技术参数研究进展

全玻璃真空太阳集热管是太阳能热利用系统的重要组成部分,其性能参数的优劣直接影响到太阳能热利用系统的热性能、耐久可靠性和节能效果。文章从真空管基本结构和工作原理的介绍出发,对影响真空管性能的光学性能、热性能等关键技术参数及玻璃管材料、真空性能等其他技术要求的研究进展做了详细分析,并在长期从事科研和检测工作的基础上,给出了提升真空管的产品性能可从玻璃管生产优化、新涂层开发、真空性能加强、技术创新、先进设备开发、标准修订等方面的建议。

AlCrNbSiTi高熵合金涂层高温水蒸气腐蚀研究

采用磁控溅射在不同偏压条件下制备AlCrNbSiTi高熵合金涂层,通过分析不同偏压涂层的形貌、化学成分、硬度,以及被水蒸气腐蚀后的涂层形貌,研究偏压对AlCrNbSiTi涂层结构及性能的影响。结果表明,偏压对涂层表面粗糙度的调控非常显著,150 V偏压的样品表面粗糙度只有3.35 nm;50 V偏压的样品具有最大硬度和弹性模量,分别为18.19 GPa和232.4 GPa。涂层水蒸气腐蚀失效机制为点腐蚀,偏压为50 V时腐蚀坑出现时间最晚,耐腐蚀性能最好。

抽油杆偏磨机理及防偏磨技术研究现状

在石油开采过程中,有杆泵是目前应用最广泛的人工举升方法之一。有杆采油系统在石油和天然气行业中被认为是一项成熟的技术,具有易于应用、使用成本低等优势,在世界范围内应用普遍。但在实际运行过程中,抽油杆与油管之间的偏磨问题较为严重,由此带来的经济损失较大。通过对抽油杆产生偏磨的原因进行分析,总结了五大类最新的防偏磨技术,并提出了现有技术的发展方向,以期对生产实践起到一定的指导作用。

Cr涂层包壳管开裂行为的研究进展

耐事故燃料相比于核电站传统的(UO_(2)/Zr)体系,可以有效地在核反应堆的正常工况中提升反应堆安全性,同时也能抵御更长时间的极限事故,由于其制造工艺成熟,经济效益较高,Cr涂层锆合金包壳在近期被认为是ATF在包壳管上部署的主流方案。但Cr涂层包壳管在服役工况下的开裂行为与失效机制却还未被深入地研究和分析,本文将以正常服役工况和典型事故工况为目标导向,收集总结国内外Cr涂层堆外性能试验的相关数据,就Cr涂层包壳的失效机制预防提出一些建议,以期为后续国内Cr涂层包壳性能优化设计提供一定的数据和理论支持。

大口径焊管中频感应加热设备数据采集系统的开发

随着用户及企业本身对产品质量的追求,其对产品过程控制越发关注,从而对设备控制参数提出了更高的要求。基于宝钢大口径焊管防腐涂层产线,介绍目前中频感应加热设备的现状和存在的问题,提出了对中频电源控制柜进行局部改造。对直流电流、直流电压、中频功率、加热温度等参数和管端信号进行采集,并采用LabVIEW软件开发一套数据采集处理系统,可根据用户需求进行数据处理,提供便捷的数据处理功能,已应用于涂层线中频电源设备的自动控制、生产管理及数字化交付等方面,效果良好。

切向位移对Cr涂层Zr-1Nb合金包壳微动磨损的影响

随着核电技术更新迭代,由于传统Zr合金包壳存在安全性能缺陷,核燃料组件安全面临严峻挑战,探索开发新型核燃料包壳管成为核电安全防护领域的重点研究。以Cr涂层Zr-1Nb合金包壳管(改良型ATF材料)为研究对象,探究切向位移对Cr涂层Zr-1Nb合金包壳管微动磨损行为及磨损机理的影响。采用白光干涉仪表征出Cr涂层Zr-1Nb合金包壳管表面磨痕的三维形貌,对Cr涂层Zr-1Nb合金包壳管表面磨痕的截面轮廓以及磨损深度进行测算。通过扫描电子显微镜(SEM)和能谱仪(EDS)对表面磨痕的微观形貌以及元素组成进行表征。结果表明:随着切向位移增加最大磨损深度随之增加,微动运行状态由部分滑移逐渐转变为完全滑移,Cr涂层Zr-1Nb合金包壳管表面的磨屑黏着现象逐渐减弱,磨损机理由黏着磨损转变为剥层磨损。所有试验中Cr涂层Zr-1Nb合金包壳管存在明显的氧化磨损。从微观角度探索了接触模型为GTR构型的改良型ATF包壳材料微动磨损机理以及微动磨损行为,制备的Cr涂层能够提高Zr-1Nb合金包壳管的微动磨损性能,有效延长包壳管的服役寿命。

碳化钨涂层盘管的制备及寿命预测

针对冶金行业蒸汽干燥机内部盘管冲蚀磨损问题,使用超音速喷涂工艺制备碳化钨涂层盘管提高盘管的使用寿命。通过显微金相检测与拉伸试验获取盘管表面状况与结合强度。基于FLUENT建立了计入壁面硬度实验值的盘管冲蚀模型,通过仿真云图与现场磨损图片进行比对,验证了数值仿真模型的合理性与真实性。将模型与冲蚀率做统一量纲化处理后,对盘管冲蚀磨损寿命进行预测。结果表明,超音速喷涂备至涂层盘管金相观测孔隙率小于0.1%,厚度大于90 um,表面硬度大于1000 HV,结合强度大于70 MPa,喷涂工艺可靠性较好;仿真结果表明,盘管冲蚀率在35°入射角附近达到最大,最大值为1.92×10^(-7) kg/(m^(2)·s);冲蚀率预测盘管极限工况使用寿命达36718750 s,较喷涂前提高约145%~167%;预测正常工况寿命41592920 s,较喷涂前提高约154%~177%。

钛纳米涂层换热器管束在大型冷换设备中的应用

针对石油化工装置中的特大型水冷器与冷凝器的设备防腐,目前主要是采用热固化涂料对换热器管束进行防腐涂装。经过实践证明,防腐蚀涂层通常使用2~3 a便会出现失效问题,其使用寿命达不到设计要求。某0.6 Mt/a甲醇深加工装置丙烯制冷剂冷凝器循环水侧管束的防腐蚀涂层已使用3 a,重点对该管束涂层的失效原因进行分析,认为其失效原因主要有两个,一是涂层材料与涂装的问题;二是涂层表面存在水垢层,造成垢下腐蚀,使换热管热阻增加,冷凝效果下降。根据换热器管束防腐涂层存在的问题,设计了一种节能防腐钛纳米涂层管束。此钛纳米涂料可常温固化,有利于现场涂装施工。管束经涂装后可以连续安全使用10 a以上,在换热器管束防腐蚀技术中,钛纳米涂层是目前综合效益最好的一种。

外海钢壳沉管隧道接头防腐施工技术研究与应用

深中通道于国内首次大规模采用了钢壳混凝土形式沉管,其施工工艺、质量控制重点不同于传统钢筋混凝土沉管,在海洋环境影响下,钢壳的防腐施工是保证钢壳沉管主体耐久性的关键之一。沉管前后端因施工过程中多种影响因素限制,沉管内部对接处的前后4 m范围为沉管防腐涂层易损区域,为保障沉管的防腐性能,需于沉管内相关前置工序完成后进行二次修复补涂。较陆地厂内涂装,二次涂装面临着高温高湿以及施工频繁交叉的作业环境,针对上述条件,在厂内防腐施工基础上改进了施工工艺及施工机具的配合方式,经现场实践证明,施工质量及效率均取得良好成效。

亲水涂层对翅片管式换热器空气侧性能的影响

为了分析亲水涂层对翅片管式换热器空气侧性能的影响,对干/湿工况下亲水涂层翅片和普通翅片管式换热器空气侧的压降和热阻进行对比试验。结果表明:相对于普通翅片管式换热器,在干工况下,亲水涂层翅片管式换热器空气侧压降略增大,空气侧热阻增大10%左右;在湿工况下,亲水涂层翅片管式换热器空气侧压降减小,空气侧热阻增大4%左右;亲水涂层翅片管式换热器空气侧热阻基本不受空气湿度的影响。

Effect of Rare Earth on the Corrosion-Resisting Performance of Zinc-Based Alloy Coatings

The corrosion behavior of coatings of pure zinc and Zn-Al,Zn-Al-RE alloys in NaCl solu- tions was studied by salt-spray experiments,even corrosion experiments and electrochemical measurements of bi-directional polarization curves and a.c.impedance in weak polarization region consistent regularities were obtained by these different methods,viz.,the corrosion resistance of Zn could be enhanced by alloying it with Al,and particularly with Al-RE.The causes of enhancement of corrosion resistance by RE were also discussed.

Study on corrosion resistance of the BTESPT silane cooperating with rare earth cerium on the surface of aluminum-tube

Bis-3-(triethoxysilyl)propyltetrasulfide(BTESPT) silane-rare earth cerium composite coatings on aluminum-tube were prepared at 60 °C by immersion method.The performance of composite coatings to protect the aluminum-tube against corrosion was investigated with potentiodynamic polarization curves,electrochemical impedance spectroscopy(EIS),and salt spray test(SST).The results of potentiodynamic polarization curves and EIS indicated that the self-corrosion current decreased by two orders of magnitude and the i...