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61.
本文介绍了由压下电动机、变频器、PLC和绝对值编码器构成的周期轧管机的压下自动控制系统。作者简介了压下工艺和设备;着重描述了该压下控制系统的硬件配置和应用程序设计。生产实践表明,该控制系统实现了对周期轧管机压下装置高效、准确的控制。 相似文献
62.
The global stability of the von Kármán boundary layer on the rotating disk is reviewed. For the genuine, radially inhomogeneous
base flow, linearized numerical simulations indicate that convectively propagating forms of disturbance are predominant at
all radii. The presence of absolute instability does not lead to the formation of any unstable linear global mode, even though
the temporal growth rate of the absolute instability increases along the radial direction. Analogous behaviour can be found
in the impulse solutions of a model amplitude equation, namely the linearized complex Ginzburg–Landau equation. These solutions
show that, depending on the precise balance between spatial variations in the temporal growth rate and the corresponding shifts
in the temporal frequency, globally stable behaviour can be obtained even in the presence of a strengthening absolute instability.
The radial dependency of the absolute temporal frequency is sufficient to detune the disturbance oscillations at different
radial positions, thus overcoming the radially increasing absolute growth, thereby giving rise to a stable global response.
The origin of this form of behaviour can be traced to the fact that the cylindrical geometry of the rotating-disk flow dictates
a choice of a globally valid time non-dimensionalization that, when properly employed, leads to a significant radial variation
in the frequency for the absolute instability. 相似文献
63.
Julia Dittrich Susen Becker Max Hecht Uta Ceglarek 《Proteomics. Clinical applications》2015,9(1-2):5-16
The simultaneous quantification of protein concentrations via proteotypic peptides in human blood by liquid chromatography coupled to quadrupole MS/MS is an important field of bioanalytical research with a high potential for routine diagnostic applications. This review summarizes currently available sample preparation procedures and trends for absolute protein quantification in blood using LC-MS/MS. It discusses approaches of transferring established qualitative protocols to a quantitative analysis regarding their reliability and reproducibility. Techniques used to enhance method sensitivity such as the depletion of high-abundant proteins or the immunoaffinity enrichment of proteins and peptides are described. Furthermore, workflows for (i) protein denaturation, (ii) disulfide bridge reduction and (iii) thiol alkylation as well as (iv) enzymatic digestion for absolute protein quantification are presented. The main focus is on the tryptic digestion as a bottleneck of protein quantification via proteotypic peptides. Conclusively, requirements for a high-throughput application are discussed. 相似文献
64.
65.
介绍立式锥形穿孔机顶杆小车电气控制系统中硬件组态、直流传动装置与PLC的通信、软件编程等内容,以及在实际运行中遇到的问题及解决办法。 相似文献
66.
Various variants and hybrid approaches evolved from the origin of Delp and Mitchell's block truncation coding (BTC) or moment preserving quantizer (MPQ) have formed a niche as an effective and simple image compression methodology with attractive coding performance achieved at moderate bitrates. As BTC is still lacking a fundamental error analysis, in this paper we present some fundamental insights regarding one-bit (or two-level) BTC's truncation error by providing mathematical analysis as well as novel geometric interpretation. We further show that the mean-square error (MSE) of Lema and Mitchell's absolute moment block truncation coding (AMBTC) is always bounded below (i.e., less than or equal to) that of BTC. Therefore, with additional advantages in computation and implementation, AMBTC is always superior. Furthermore, we developed a new adaptive equal sign position optimization (ESPO) algorithm for optimum pixel classification. Our quantization error analysis shows that incorporating the ESPO algorithm into conventional AMBTC or BTC achieves minimum MSE in either case. 相似文献
67.
A high or low humidity environment is related closely to not only many health problems, but also has great influence on the construction durability and energy consumption. It is very important to control humidity level, in order to achieve a healthy and comfortable indoor environment. However, various problems of the air humidity in inhabited dwellings are not yet taken serious consideration in China. Moreover, there is hardly any information available regarding the actual humidity environment in Chinese residential houses. For this reason, it is difficult to select appropriate moderate moisture strategies to maintain a harmonious indoor humidity level. 相似文献
68.
刘凯 《石油化工设备技术》2001,22(6):43-44,54
简述磁力传动在反应釜中的应用原理及设计方案,针对异辛酸磁力传动高温反应釜的设计实例,指出了在设计、制造、安装和调试中应注意的关键性技术问题,并提出了建设性的意见及其未来的发展方向. 相似文献
69.
高压气井产能评价方法研究 总被引:6,自引:4,他引:2
确定气井产能有回压试井、等时试井与修正等时试井,这些方法所需的试井时间长,且增加勘探成本。此外,高压气井试井时开井期井底压力常出现上升现象,有时出现油嘴大(产量高)井底流压也大的现象,导致不能建立产能方程,从而得不到绝对无阻流量。因此,研究高压气井产能评价方法有其必要性。 相似文献
70.
Satoshi Murakami Kazuhiro Satou Taturo Kijima Masataka Watanabe Taeko Izumi 《European Journal of Lipid Science and Technology》2011,113(4):450-458
The enantiopure of (R)‐(?) MαNPA was allowed to react with racemic 18‐(tert‐butyldimethylsilyloxy)‐5‐octadecayne‐7‐ol which was derived from dodecane‐1,12‐diol, yielding diastereomeric esters mixture. These racemic esters were easily separated by HPLC on silica‐gel. The absolute configurations of the first‐eluted diastereomeric esters from the separated esters were determined using 1H NMR anisotropy method. Analysis on 1H NMR spectra and HPLC elution time of the synthesized esters and those of MαNP ester derived from natural methyl‐12‐hydroxystealate showed that the absolute configuration of natural 12‐hydroxystearic acid was R form, and the enantiomeric excess was over 99%. 相似文献