Glidants and Lubricant Properties of Several Types of Talcs

Abstract

Glidant and lubricant efficiencies of a number of different types of talcs were evaluated. The in vitro properties of tablets lubricated with talcs were compared to those lubricated with magnesium stearate. Talc lubricated tablets showed superior in vitro properties compared to magnesium stearate lubricated tablets. Different sources of talcs showed significant differences in glidant and lubricant efficiencies.     

The Tabletting Properties of Dika Fat Lubricant

The lubricant property of dika fat, a solid vegetable oil extracted from the kernels of Irvingiaqabonensis var gabonensis and var excelsia was investigated. An instrumented tablet machine (ITM) was used to evaluate the effect of dika fat on the unit ejection force (EJF/A) of a model direct compression formulation. Dika fat, at equivalent concentration levels, performed better than magnesium stearate, stearic acid and a hydrogenated vegetable oil STEROTEX, in reducing EJF/A of tablets compressed from the model direct compression formulation. Dika fat imparted no adverse effect on the hardness, disintegration and dissolution of directly compressed hydrochlorothiazide tablets prepared in this study.     

The Tabletting Properties of Dika Fat Lubricant

Abstract

The lubricant property of dika fat, a solid vegetable oil extracted from the kernels of Irvingiaqabonensis var gabonensis and var excelsia was investigated. An instrumented tablet machine (ITM) was used to evaluate the effect of dika fat on the unit ejection force (EJF/A) of a model direct compression formulation. Dika fat, at equivalent concentration levels, performed better than magnesium stearate, stearic acid and a hydrogenated vegetable oil STEROTEX, in reducing EJF/A of tablets compressed from the model direct compression formulation. Dika fat imparted no adverse effect on the hardness, disintegration and dissolution of directly compressed hydrochlorothiazide tablets prepared in this study.     

纳米铜润滑油添加剂的制备及其摩擦学性能

为了研究纳米铜粉的制备与其摩擦学性能,利用高能球磨机采用干湿磨相结合的方法制备了纳米铜粉,再将其加入500SN齿轮油中制成润滑油添加剂,用透射电镜(TEM)及万能磨擦磨损试验机研究了纳米铜粉的微观形貌及其润滑油添加剂的摩擦学性能。结果表明:纳米铜粉粒径为10～40 nm,在修饰剂中分散较好,颗粒表面有明显包覆层;纳米铜润滑油添加剂可提高基础油的减摩抗磨性能;纳米铜粉含量0.05%的纳米铜润滑油样的摩擦学性能最好且摩擦系数最低;低载荷下纳米铜润滑油样的摩擦学性能优于高载荷下的。     

几种粉尘层反应动力学参数的研究

研究了两种烟煤和玉米淀粉、石权子粉粉尘层的反应动力学参数。实验是采用热重分析方法在氧浓度分别为0、2％、8％、20％、50％和100％及层流条件下进行的．并用气相色谱在不同的温度范田内对粉样的气相成分进行了分析，依据实验结果求出上述4种粉尘的氧化、热解动力学参数并对粉尘层氧化某些机理作了描述。     

Experimental Study on the Rheological Properties of MF Lubricant Based on the Herschel-Bulkley Model

Journal of Superconductivity and Novel Magnetism - As an effective method to improve the load capacity of the oil-film bearing, a kind of nano-scale magnetic fluid (MF) by taking silicon oil as...     

Asymptotic Properties of Several Estimators of Weibull Parameters

In this paper several estimators for the scale and the shape parameters of the Weibull law are obtained by postulating a stochastic model aimed at studying the aging process of certain inexpensive industrial products. These estimators are consistent and asymptotically multi-normal.     

Cu／C复合润滑剂的摩擦学性能

将纳米Cu和纳米金刚石复配成Cu／C复合添加剂,对Cu／C复合添加剂在500SN基础油中的减摩抗磨性能进行了研究。结果表明：Cu／C复合试油能明显改善500SN基础油的摩擦学性能,当纳米Cu的添加量为4％,纳米C的添加量为2％时,Cu／C复合试油的减摩效果最好,同500SN空白试油相比,摩擦系数可降低94．8％;当纳米Cu的添加量为3％,纳米C的添加量为4％时,Cu／C复合试油的抗磨效果最好,同500SN空白试油相比,磨损量减少108．6％。     

关于金属纳米材料力学性能的几个问题

金属纳米材料具有独特的力争陛能,如高强度、超高延展性和理想弹塑性等。本文通过对几种纳米金属材料的力学性能的阐述,讨论了它们的强度、应变硬化、超塑性、理想弹塑性等相关的力学性能。并简要地指出了影响其力学性质的主要因素。     

Influence of the Physicochemical Variability of Magnesium Stearate on Its Lubricant Properties: Possible Solutions

The variability of the physicochemical properties of 13 commercial batches of magnesium stearate (from three vendors) were determined using various physicochemical tests. Differences observed were related to the crystal lattice and the hydration state of the samples as well as the impurities contained in their matrices. A formulation model containing 2% of magnesium stearate was used to determine the lubricant properties of 6 of the 13 magnesium stearate lots received. The tablet press used was a Stoks® Single Station Instrumented F Press. The different lubricant properties observed were related to the particle size of the magnesium stearate lot used. The influence of the crystalline structure on the lubricant properties of magnesium stearate was also shown whereas the influence of the adsorbed water did not appear to determine process capabilities. Two possible solutions were evaluated to reduce the lubricant property differences among the lots tested. By decreasing the particle size of a lot of magnesium stearate, it has been possible to significantly improve its lubricant properties. Magnesium stearate in association with talc also presented an improvement of its lubricant properties.     

基于量子逻辑的几类有穷自动机之间的关系

根据初始状态和终止状态是否为分明的,非确定型量子有穷自动机可分为四类,确定型量子有穷自动机可分为三类.本文详细讨论了四类非确定型量子有穷自动机之间的关系以及三类确定型量子有穷自动机之间的关系,并且利用新的构造方法,证明了初态为分明的确定型量子有穷自动机与终态为分明的确定型量子有穷自动机是等价的.这些结论为实际应用中计算模型的合理选取提供了理论依据.     

Influence of the Physicochemical Variability of Magnesium Stearate on Its Lubricant Properties: Possible Solutions

Abstract

The variability of the physicochemical properties of 13 commercial batches of magnesium stearate (from three vendors) were determined using various physicochemical tests. Differences observed were related to the crystal lattice and the hydration state of the samples as well as the impurities contained in their matrices. A formulation model containing 2% of magnesium stearate was used to determine the lubricant properties of 6 of the 13 magnesium stearate lots received. The tablet press used was a Stoks® Single Station Instrumented F Press. The different lubricant properties observed were related to the particle size of the magnesium stearate lot used. The influence of the crystalline structure on the lubricant properties of magnesium stearate was also shown whereas the influence of the adsorbed water did not appear to determine process capabilities. Two possible solutions were evaluated to reduce the lubricant property differences among the lots tested. By decreasing the particle size of a lot of magnesium stearate, it has been possible to significantly improve its lubricant properties. Magnesium stearate in association with talc also presented an improvement of its lubricant properties.     

两种Ni-Zn铁氧体复合材料的烧结性能和射频磁性能*

用sol-gel法获得了两种铁氧体复合材料：以镁橄榄石为基体的Ni-Zn铁氧体复合材料和以MAS为基体的Ni-Zn铁氧体复合材料。比较了这两种复合材料的结晶性能和烧结性能。两种复合材料在射频区（100MHz-1GHz)的磁性能优于纯Ni-Zn铁氧体,这种优于纯Ni-Zn铁氧体的磁性能与复合材料的显微结构密切相关：复合材料中Ni-Zn尖晶石晶粒的尺寸较一般纯Ni-Zn铁氧体晶粒尺寸小一个数量级,晶粒间的磁相互作用较纯铁氧体晶粒间弱。     

Turning of Brasses Using Minimum Quantity of Lubricant (MQL) and Flooded Lubricant Conditions

A lot of effort is being carried out to reduce the use of lubricants in metal machining operations from the viewpoint of cost, ecology and human health issues. Minimal quantity lubrication (MQL) is now an established alternative to conventional flood lubricant system. This paper reports on the experimental work carried out during turning of brasses with different amounts of MQL. Turning with flood lubrication was also performed and a comparison is made. The various parameters studied include the feed, cutting power, specific cutting power, and surface roughness. The results of the study suggest that with proper selection of the MQL system, results similar to flood lubricant condition can be achieved.     

三种锡摩擦涂层的表面分析和摩擦学特性研究

针对钢一铜摩擦副类机械零件表面的磨损,研制了有减摩抗磨功能的锡类和锡锌复合类自修复添加剂.在摩擦试验中,润滑剂中的软金属微粒在机械作用下均能转移至铜表面上形成金属涂层.用俄歇能谱仪和扫描电镜分析了涂层表面的主要元素、涂层的形貌和厚度.测试结果表明,当润滑剂中的锡含量为20%时,涂层中锡的原子浓度接近80%,涂层厚度为10 μm;若在润滑剂中同时加入锡和锌两种微粒,经摩擦形成的锡锌涂层厚度为20 μm.锡脂和锡锌复合脂有较好的稳定性和防颗粒沉降性能.在MS-800摩擦磨损试验机上分别进行了纳米锡润滑剂、锡半流体脂和锡锌复合半流体脂的摩擦磨损特性,含锡量较高的涂层减摩抗磨性能较好,而加入锡锌两种添加剂形成的复合涂层具有更为优越的减摩特性.     

几种中药渣/PP复合材料的制备与性能

对几种中药渣(山芝麻,葫芦茶,三叉苦,广霍香)进行蒸汽爆破处理,以马来酸酐改性无规共聚聚丙烯(MAPP)作为相容剂,与聚丙烯(PP)复合制备复合材料,实现几种中药渣废弃物资源的高值化利用。分析了各药渣的主要成分,用扫描电镜(SEM)观察药渣及复合材料拉伸断面的形貌。结果表明,蒸汽爆破处理药渣可使纤维束解离出纤维细胞作为增强材料;药渣纤维的种类影响复合材料的拉伸和弯曲性能,选用木质化程度高、半纤维素含量低、杂细胞少的药渣有利于制备出综合性能较好的复合材料。     

含磷摩擦改进剂的抗磨协同性能研究

利用四球试验机评价了含磷摩擦改进剂TPO与两种二烷基二硫代磷酸锑(SbDDP1、SbDDP2)、二烷基二硫代氨基甲酸锑(SbDDC)、硫化二烷基二硫代磷酸氧钼(MoDDP)共4种添加剂的抗磨性能以及它们之间的抗磨协同作用.结果表明,TPO、SbDDP和MoDDP都具有较好的抗磨性能,其中MoDDP最佳.当TPO分别与上述4种添加剂复合后,均表现出了不同程度的抗磨协同效应,其中TPO与SbDDP2和SbDDC的协同效果较好,尤其是复配浓度达到最佳比例时,协同效果最佳.     

纳米金属Cu粉制备新方法及其对润滑油性能的影响

以无机铜盐为铜源,加入正己醇、span-80、tween-80,在N2气氛保护下,制得粒度可控、粒径在20-50nm的纳米铜,经SEM分析为球形,用四球摩擦试验机测试含有纳米铜润滑油的极压抗磨性能,结果表明,纳米铜粉的粒度越小,润滑油的极压抗磨性能越佳。     

In Vitro Measurements of Mucoadhesive Properties of Six Types of Pectin

ABSTRACT

The objective of this study was to measure and compare the specific- and general mucin interaction of six pectin types from three manufacturers, differing mainly in the degree of methoxylation and degree of amidation. Mucoadhesive properties were measured using a texture analyzer. It was found that an intermediate degree of methoxylation (35 and 36%) improved the specific mucin interaction. Amidation did not increase mucin interaction. Samples from different manufacturers did not alter these conclusions. This study indicates that the general classification of pectin as a poor mucoadhesive, without differentiating between the amount and type of substituents, probably is an oversimplification.