盐酸环丙沙星含量测定方法的研究

本文介绍了盐酸环丙沙星含量测定的离子选择电极法，紫外分光光度法和格兰线性滴定三种不同方法。用于原料药回收率的测定分别为９９．４％，９９．６７％和９９．５％；用于片剂回收率测定分别为９８．８５％，９８．８４％和９８．７３％。结果基本相同，与非水滴定法相比具有测试方便、快速等优点。     

镍-磷/纳米碳管化学复合镀层的研究

采用化学复合镀方法,在基体铜片上进行Ni-P／纳米碳管复合镀．用金相显微镜、扫描电子显微镜、X射线衍射仪和显微硬度计等实验手段研究复合镀层的组织、结构和性能．结果表明:随着镀液中纳米碳管含量的增加,复合镀层表面的颗粒变小且密度增加;复合镀层的硬度随纳米碳管含量的增加而提高;此外,纳米碳管的加入,使镀层由非晶变成了纳米晶,促进了复合镀层的晶化．     

流动注射在线萃取－火焰原子吸收光谱法测定明胶中的微量Fe和Cu

本文采用氧化水解制样及流动注射在线萃取火焰原子吸收光谱法，测定明胶中微量Ｆｅ和Ｃｕ，解决了水解法制样测定结果偏低和不能直接测定低含量样品的问题。本方法测定Ｆｅ和Ｃｕ的灵敏度分别提高了１４．５倍和１７．６倍，分析速度达３６次／ｈ，Ｆｅ和Ｃｕ的回收率分别在９０．８－１１０．５％和８７．５～１０７．０％之间，测定精密度分别为４．５３％和４．２６％。     

P—矩阵法测定安钠咖注射液中两组分的含量

本文采用Ｐ－矩阵法不经分离同时测定安钠咖注射液中咖啡因和苯甲酸钠的含量。计算程序用ＢＡＳＩＣ语言编制。咖啡因和苯甲酸钠的平均回收率分别为１００．０和９９．９５％，变异系数分别为０．４０％和０．６５％，方法简便，快速，样品测定结果与药典法测得结果基本一致。     

微波消解-原子吸收分光光度法测定魔芋粉中铜、铁、锰、锌的含量

将硝酸和过氧化氢放入聚四氟乙烯密闭罐中，置于家用微波炉内，微波消化魔芋粉，火焰原子吸收分光光度法测定铜、铁、锰、锌的含量。回收率为95．2％－106．4％，相对标准偏差为1．0％－3．9％。方法快速、简便，具有良好的精密度和准确度。     

火焰原子吸收法测定霞石中的氧化钾和氧化钠

本方法用于测定霞石中的钾、钠，主要通过在溶样时加入氢氟酸除去二氧化硅，调整溶液中钾、钠的含量，消除互相之间的干扰，加入氯化铯消除电离因素的干扰，提高了分析结果的准确性和重现性，使测定结果更接近化学分析值。回收率为99．2％-101．6％，总体标准偏差为0．04％。     

血浆和组织中皮质酮的荧光测定法

皮质酮是肾上腺皮质激素之一。本文试验研究了用荧光分光光度法测定小哺乳动物血浆和组织中皮质酮含量的方法。方法的线性范围为０．０１－０．２４μｇ／ｍＬ，标准回收率平均为９６．０％，相对标准偏差为４．２％。本法具有快速，准确和灵敏度特点，能同时运用于血浆或肾上腺组织中皮质酮的测定。     

原子吸收光谱法间接测定硫酸阿托品

研究了原子吸收光谱法间接测定硫酸阿托品的方法。在pH为5．0的溶液中，当四苯硼钠过量时可完全沉淀硫酸阿托品，在滤液中加入过量的氯化钾沉淀剩余的四苯硼钠，再测定过量的钾可以计算得到硫酸阿托品的含量。方法简单、快速，回收率在97％－101％之间，相对标准偏差为1．1％。     

NMR法测定复方制剂3组份的相对含量

本文对复方制剂中盐酸伪麻黄碱（Pse)、盐酸苯海拉明（Dip)和氢溴酸右美沙酚（Dex)3组份进行了NMR相对含量的测定。RSD分别为2.22%、3．18％、3．35％，绝对误差（E）分别为1．87％、3．66％、4．23％，方法简便快速，且相当准确。     

火焰原子吸收法间接测定代森锰锌中有效成份的方法研究

本文提出了以原子吸收法间接测定喷克中有效成分含量的新方法。实验结果表明方法具有良好的准确度和精密度。测定快速、简便，相对标准偏差为0．136％．此法与CIPAC法对比，结果满意。     

Effect of deformation on the electrochemical behavior of hot-dip galvanized steel sheets

The main purpose of employing pre-coated steel sheets is to minimize corrosion of steel. However, coatings can be severely affected by forming processes. In the forming processes, due to the different modes of deformation, the strain levels are different and so can affect the properties of the coatings to a varying degree. Special attention has to be paid to the influence of deformation conditions on the performance of the coating, as regards protection against corrosion. The adhesion of the coating must remain good, and the surface should not be damaged during forming. Therefore, it is necessary to study the behavior of its corrosion resistance against the deformation.In this work, effect of strain path on the corrosion behavior of hot-dip galvanized steel sheets has been studied. Corrosion behavior of hot-dip galvanized steel sheets at various strain levels has been evaluated under four different strain paths namely, biaxial, plane strain, uniaxial (drawing) and tensile modes. The sheets were deformed by a limiting dome height test (LDH) set-up. A correlation between the degree of deformation and the loss in extent of corrosion protection offered by the coating has been established by carrying out electrochemical studies such as potentiodynamic polarization and impedance spectroscopy (EIS) in 3.5% NaCl solution. The present study shows that increase in deformation increases the extent of delamination of the coating for all the modes of deformation. The severity of deformation on delamination, however, has been found to vary in the order of, tensile < uniaxial < plane < biaxial.     

Effect of coating thickness on modifying the texture and corrosion performance of hot-dip galvanized coatings

Hot-dip galvanized zinc coating is the most frequently used among coatings to protect steel against corrosion. When coated steel sheets are subjected to a corrosive environment, its corrosion behaviour is affected by texture and microstructure variations. The aim of this research work was to study the texture and corrosion resistance of hot-dip galvanized zinc coatings affected by the coating thickness and chemical composition of the zinc bath. Texture of the coatings was evaluated employing X-ray diffraction whilst its corrosion behaviour was analyzed using Tafel polarization test. Experimental results showed that (00.2) basal texture component would be weakened by increasing the lead content of the zinc bath and coatings with strong (00.2) texture component have lower corrosion current density than the coatings with weak (00.2) texture component. Furthermore, it was inferred that by increasing the thickness of the coatings with the same content of lead in the zinc bath, the relative intensity of (00.2) texture component and corrosion resistance of the coatings would be decreased and conversely, relative intensity of (20.1) high angle pyramidal planes and (10.0) prism planes would be increased due to establish a balance between surface and strain energies. Besides, five types of morphology were observed on the surface of hot-dip galvanized coatings in dull and bright spangles. Finally, it was recognized that the main corrosion product of the salt spray test is Simonkolleite.     

Laser welding of low-thickness zinc-coated and uncoated carbon steel sheets

Laser welding is a competitive joining process for low-thickness plates. The speeds achieved with laser welding using a CO₂ laser and the low heat input introduced to the base material are the main advantages of this process. The widespread use of laser welding will increase the productivity and accuracy of welding operations. Nevertheless, there are still important developments to be made.The results of laser welding of thin sheets (below 1.25 mm) of uncoated and zinc-coated carbon steels are presented. A CO₂ laser was used for the welding of sheets of different thicknesses and to make dissimilar welds (carbon steel to zinc-coated steel). The bead dimensions and the distortions of the welded sheets are analysed.     

A Mössbauer Study on Gray Stains in Electrogalvanized Steel

Transmission Mössbauer Spectroscopy (TMS) and Conversion Electron Mössbauer Spectroscopy (CEMS), together with X-ray diffraction (XRD) are applied to identify the origin of stain defects formed on one-side zinc-coated steel used in the automotive industry. The stained sheets were directly exposed to CEMS meanwhile absorbers for TMS were obtained by tape, scrapping, paper and ultrasound bath. Measurements, both by TMS and CEMS, show the presence of the -Fe signal in all the cases. CEMS measurements also indicate that a Mössbauer inactive coating covers the stained areas. Fe₃C and Fe–C signals, as minor ones, appear only when the absorber is prepared by paper. Results show that the stains are not due to a corrosion process and therefore the corrosion performance of the steel should not be affected by the presence of the stains over the non plated side. An incomplete cleaning of the oil used to protect the steel before entering the electrogalvanizing line would have produced the stains.     

Dual beam method for laser welding of galvanized steel: Experimentation and prospects

Laser welding of zinc-coated steel sheets in lap configuration poses a challenging problem, because of the zinc vapours spoiling the quality of the weld. In continuation to the earlier work, the novel solution of dual laser beam method for lap welding of galvanized steel sheets is discussed here in view of the recently obtained observations and ensuing concerns. In this method the precursor beam cuts a slot, thus making an exit path for the zinc vapours, while the second beam performs the needed welding. The metallurgical analysis of the welds is encouraging showing absence of zinc in the welded area. In the current work on this technique, new experimental results have been obtained verifying the earlier observations. Along with this, the possibility of using a transversely split-up beam for the welding purposes with this approach is discussed and analyzed in this paper. This new technique is expected to be very useful in prospective industrial applications requiring higher welding throughput along with the needed quality.     

Improvement of hot-dip zinc coating by enriching the inner layers with iron oxide

The performance of hot-dip galvanic coating formed on steel not only depends on the alloy composition of the superficial layer but also significantly, on the composition of the inner alloy layers at the coating/substrate interface. Further, the presence of barrier oxide layers, if any can also improve the performance of galvanic coating. In the present work, the effect of inner iron oxide barrier layer formed prior to hot-dip galvanization was investigated. A continuous and adherent iron oxide layer was formed on steel by anodic oxidation of the steel substrate. Although the wettability of oxide surface by liquid zinc was initially poor, the increase in dipping time and the transition of the oxide layer to unstable form due to the presence of Cl⁻ ion in the flux facilitated localized growth of Fe-Zn alloy phases. The inhibitive nature of the oxide layer was temporary, since the presence of Cl⁻ induces micro cracks on the oxide surface thereby facilitating better zinc diffusion. The modification of the substrate structure during galvanization was found to influence the galvanizing process significantly. The present study predicts scope for application of this process for protection of rusted steel specimens too.     

Modification of galvannealed steel through aluminum addition

Aluminum is believed to modify and to some extent control the coating characteristics of commercially produced galvanneal sheet steel. These include mechanical, chemical, and aesthetic properties. Whereas the aluminum added to the molten zinc bath is known to form intermetallics before the steel is annealed, our research is primarily concerned with the effect aluminum has on suppression or enhancement of the particular iron--zinc alloy phases in the coating during galvannealing. The microstructure of four commercially important iron--zinc intermetallic phases containing varying aluminum content between 0--1.5 weight percent has been studied. It is also believed that an iron--aluminum alloy, known as the inhibition layer, forms on the steel surface following hot dipping and prior to annealing. Transmission and scattering Mössbauer spectroscopy as well as X-ray diffraction have been used to identify iron--zinc and iron--aluminum alloys present in the coatings. Discussion will be presented on the effect aluminum has on phase suppression for Fe--Zn alloys prepared in commercially produced galvanneal.     

Ensembles of aluminum islands on the surface of strained poly(ethylene terephthalate) films

This paper reports on a study of the size distribution of aluminum islands forming an aluminum-coated poly(ethylene terephthalate) film subjected to tension. The islands are shown to form four statistical ensembles, with the distribution in each of them being thermodynamically optimized and coinciding with the canonic distribution of thermodynamic probability.     

Development and evaluation of electroless Ag-PTFE composite coatings with anti-microbial and anti-corrosion properties

Electroless Ag-polytetrafluoroethylene (PTFE) composite coatings were prepared on stainless steel sheets. The existence and distribution of PTFE in the coatings were analysed with an energy dispersive X-ray microanalysis (EDX). The contact angle values and surface energies of the Ag-PTFE coatings, silver coating, stainless steel, titanium and E. coli Rosetta were measured. The experimental results showed that stainless steel surfaces coated with Ag-PTFE reduced E. coli attachment by 94-98%, compared with silver coating, stainless steel or titanium surfaces. The anti-bacterial mechanism of the Ag-PTFE composite coatings was explained with the extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The anticorrosion properties of the Ag-PTFE composite coatings in 0.9% NaCl solution were studied. The results showed that the corrosion resistance of the Ag-PTFE composite coatings was superior to that of stainless steel 316L.     

激光诱导击穿光谱分析钢中酸不溶铝含量

激光诱导击穿光谱(LIBS)具有分析速度快、非接触测量、表面微区分析以及易于实现在线实时监控分析等优点。通过LIBS对块状钢铁样品表面进行扫描分析,实现了钢中酸不溶铝含量的定量表征。铝的异常信号采用Nalimov迭代法剔除,以剩余信号强度的平均值加三倍标准偏差作为阈值强度,高于阈值强度的信号认为由酸不溶铝产生,反之由酸溶铝产生。在用含量校准曲线获得钢中总铝的含量后,分别根据酸不溶铝信号总强度或信号总个数与总铝信号之比,计算钢中酸不溶铝的含量。几种钢铁标准样品及实际生产板坯样品中酸不溶铝含量的对比分析结果表明,根据铝信号总强度获得的分析结果与传统湿法分析结果吻合得更好,可用于快速定量表征钢中酸不溶铝的含量。