涤纶短纤维纺丝组件的使用与异常丝控制

简述了纺丝组件的结构、作用,探讨了纺丝异常丝的形成,指出熔体杂质含量高、黏度大、纺丝温度低时组件的升压速度快,注头丝、浆块类异常丝与组件相关,其控制要从组件更换、喷丝板面硅修整、组件拆装、清洗规范操作、喷丝板镜检及部位管理着手。     

UPS平衡并机系统共用电池组的利弊分析

伴随着信息时代的到来,UPS作为保障供电稳定和连续性的重要设备,被越来越广泛的使用。以某高速公路收费站实际建设需求出发,简要阐述UPS平衡并机系统共用电池组的控制原理及实现方式,分析了探讨方案的利与弊,以供同行参考。     

Porous Ultrahigh Gas‐Permeable Polypropylene Film and Application in Controlling In‐pack Atmosphere for Asparagus

Porous polypropylene (PP) films with greater gas permeability and lower permeability ratios (β) than existing commercial films were developed for fresh produce packaging. PP containing high content of beta‐form crystal was biaxially stretched under controlled conditions. Resulting porous films with uniquely high oxygen transmission rate (OTR) of 2 659 000 cm³?m^?2?d^?1, water vapor transmission rate of 67 g?m^?2?d^?1, and β value of 0.76 was used as a “breathable window” attached to the less permeable commercial BOPP (biaxially oriented PP) lidding film. Various sizes/areas of the breathable windows were designed and tested on packaging asparagus of 400 g, at 5°C. Results demonstrated that in‐pack O₂ and CO₂ concentrations could be practically controlled and modified by changing areas of the breathable windows. Altered porous high OTR area directly affected total gas permeation of the package. Optimum gas composition of Ο₂ and CΟ₂ within the recommended controlled atmosphere for asparagus, stored at 5°C, was effectively created and maintained in the package containing 25 cm² breathable window (15% of total film lid's area). The shelf life of asparagus under optimum modified atmosphere was extended to 29 days, as compared with <3 days in the normal, low OTR tray sealed with BOPP lidding film. Clearly, these developed porous ultrahigh permeable PP films can be useful materials in designing high OTR package with desirable in‐pack O₂ and CO₂ concentrations. Copyright © 2013 John Wiley & Sons, Ltd.     

浅谈压缩空气的无菌处理

在化工，食品以及药品发酵生产中，所有发酵菌均需消耗氧气，而工业生产中通常采用空气作为氧源，由于空气中含有各种微生物，因此在实际生活中，须对空气进行净化处理。本文结合工程实例，讨论了压缩空气净化处理过程中应注意的几个关键过程。     

一种计算射孔-砾石充填井表皮系数的新方法

在以往对砾石充填井压降分析的基础上，给出了一种以普通径向流方程为基础计算井筒附近收敛流动和射孔一砾石充填段的压降，再根据完善井与非完善井压降之间的关系，求出表皮系数的方法。通过实例计算，体现了孔深、孔径、孔密等不同射孔参数和地层参数对表皮系数的影响，验证了此方法的正确性与可靠性，同时对准确认识地层、评价油层伤害、优化油气井的增产措施提供了有益的指导。     

固体渗硼剂中氟硅酸钠作用的研究

本文对Ｎａ２ＳｉＦ６和ＫＢＦ４在以硼铁为供硼剂的固体渗硼剂中的活化作用进行了试验研究和热力学分析。结果表明，Ｎａ２ＳｉＦ６的活化作用大于ＫＢＦ４。尤其在较低渗硼温度下，Ｎａ２ＳｉＦ６的活化作用更加明显。这对固体渗硼剂组成的进一步改进和渗硼处理工艺的优化具有一定的参考价值和指导意义。     

Basic functional analysis of six unknown open reading frames from Saccharomyces cerevisiae: four from chromosome VII and two from chromosome XV.

Six open reading frames (ORFs) of unknown function from Saccharomyces cerevisiae from the left arms of chromosomes VII and XV were disrupted by the short-flanking homology method in the diploid strains FY1679 and CENPK2. In each case, the entire ORF, with the exception of the first nucleotide of the start codon, was eliminated and replaced by the kanMX4 cassette. Correct integration of the disrupting marker was checked by colony PCR of the geneticin (G418)-resistant transformants. Sporulation followed by tetrad dissection of the diploids revealed that none of the ORFs encoded a product essential for the viability of either yeast strain. The neutral effect of these disruptions extended to mating and sporulation, since it was possible to create homozygous diploid disruptants that were capable of sporulation. Basic phenotypic analysis was carried out on all strains by growing them on three different media at three different temperatures and revealed no significant differences between disruptants and the parental strains. A cognate clone and a kanMX4 disruption cassette were created for five of the six ORFs by gap repair with specific long-flanking homology cassettes. For experimental reasons, the cognate clone and disruption cassette corresponding to the sixth ORF (YGL161w) had to be created by PCR.     

Aluminide Coatings Formed on Fe–13Cr Steel at Low Temperature and its Oxidation Resistance

A novel aluminizing process has been developed to produce aluminide coatings on Fe–13Cr stainless steel at a much lower temperature (520–600 °C) and with a shorter time (60–240 min) compared to the conventional pack-aluminizing processes. In this process, chemical reaction and atomic diffusion were accelerated by ball impact generated by mechanical vibration. The effects of operation temperature and duration on the coating thickness were studied. Scanning-electron microscopy (SEM and EDS) showed that the coatings appeared to be dense, homogeneous, free of porosity and with excellent adherence to the substrate. X-ray diffraction (XRD) analyses indicated that the coatings consisted mainly of η-Fe₂Al₅ and θ-FeAl₃. High-temperature oxidation tests were carried out in air at 900 °C. The results indicated that the aluminide coatings obtained from this process have significantly improved high-temperature oxidation resistance.     

Pack Aluminide Coatings Formed at 650 °C for Enhancing Oxidation Resistance of Low Alloy Steels

THE COMMERCIAL ALLOY STEELS containingtypically9-12wt.%Cr and1wt.%Mo are low costmaterials developed for critical strength engineeringapplications at temperatures up to700°C[1-2].Thecomposition and microstructure of these materials arenormally optimised to provide the required mechanicalstrength and creep/fatigue resistance.However,thehigh temperature oxidation resistance is often notsufficient to prevent premature failure caused byoxidation degradation,particularly in high temperat…     

Formation and Microstructural Characterization of Silicon-modified Aluminide Coating on Nickel-based Superalloy IN738LC

ALUMINIDE COATINGS are used extensively forprotecting gas turbine hot section components due totheir high oxidation resistance and low capital cost.However,for some application,their properties must bemodified by adding elements such as Cr,Si and Pt tomeet high performance gas turbines requirements[l,2].Although silicon is less efficient as a protective scaleformer than chromium and aluminum,silicon-modifiedaluminide coatings,have shown better hot corrosionresistance(specially to type …