滑阀污染敏感尺寸的确定

本文根据滑阀运动副发生污染卡紧与污染磨损的污染物尺寸条件,给出了滑阀污染敏感尺寸范围。试验结果很好地证明理论分析的正确性。这对于确定液压系统中滑阀所需要的过滤精度具有重要价值。     

阿那其根醇提取物对两种炎症模型作用机制研究

目的: 研究阿那其根醇提取物(EERAP)对二甲苯致小鼠炎症模型和脂多糖(LPS)诱导RAW264.7细胞炎症模型的影响。方法: 将50只小鼠,随机分为对照组(饮用水)、EERAP高剂量组(640 mg/kg)、中剂量组(320 mg/kg)、低剂量组(160 mg/kg)和阿司匹林组(120 mg/kg),采用二甲苯建立小鼠炎症模型,比较小鼠耳廓肿胀度及耳廓毛细血管通透性的变化,ELISA法测定各组炎症渗出液丙二醛(MDA)、超氧化歧化酶（SOD）的含量;LPS诱导RAW264.7细胞建立细胞炎症模型,ELISA法测定核转录因子kappa B（NF-κB）和肿瘤坏死因子-α（TNF-α）含量。 结果: 在二甲苯致小鼠炎症模型中,EERAP高、中、低剂量组均能抑制小鼠耳廓肿胀度,减少小鼠耳廓毛细血管通透性,减少渗出率,与空白对照组比较均有统计学差异(P<0.01);EERAP高、中、低剂量组均能降低血清中MDA含量（P<0.05）,显著升高SOD含量(P<0.01);在LPS诱导的RAW264.7细胞炎症模型中,EERAP在3.125～200 μg/mL范围内可降低TNF-α含量,而在2 μg/mL时也可以降低细胞NF-κB含(P<0.05),与阿司匹林组无统计学差异。结论: EERAP可能是通过抑制MDA、TNF-α和NF-κB的生成,升高SOD的水平,起到抗炎、抗氧化作用。     

图的着色理论在自动导引小车调度规划系统中的应用

针对目前AGVS(自动导引小车系统)的调度问题的研究现状,为解决AGVS在FMS(柔性制造系统)中的调度次数最优化的问题,文章提出通过图的着色理论来研究满足一定约束的AGVS中调度问题,为满足此类约束条件的AGVS,给出一种行之有效的方法.理论分析结果表明,该方法能够在完成调度任务的同时,能够使AGVS的调度次数最优.图的着色理论对于此类问题的研究,较传统的方法,运算简单,求解直观.与此同时,该方法还可以确定此类问题背景下的系统所需小车的最小值.     

Study of the effect of a number of oxidizers on variation of composition of surface functional groups,porous structure,and adsorption properties of composite carbon-carbon sorbent

The oxidation of a carbon-carbon composite sorbent by a number of oxidants results in the variations of the chemical nature of the surface, including an increase in the overall content of surface oxygen-containing groups and, in separate cases, increased variations in its structure-chemical characteristics, primarily in an increase in the percentage of large mesopores. The oxidative modification of the initial sorbent increases the hydrophilicity of its surface and enhances the specific sorption of water vapors.     

Effect of the velocity of equal-channel angular pressing on the formation of the structure of pure aluminum

Transmission electron microscopy, X-ray diffraction, and electron back-scattering pattern analysis have been used to investigate the effect of the speed of equal-channel angular pressing (ECAP) at room temperature on the formation of ultrafine-grained structure in pure aluminum. It has been established that eight ECAP passages with a pressing speed of 3.3 × 10^?2 mm/s results in the formation in aluminum of a substantially inhomogeneous grain structure with a grain size in the range of 1–27 μm (average size 3.0 μm). An increase in the speed of pressing by an order of magnitude leads to an increase in the level of internal stresses and dislocation density, an increase in the upper boundary of the interval of the grain-size distribution and in the average grain size (to 3.4 μm), and a decrease in the number of boundaries with high-angle misorientations. It is assumed that these changes are connected with the fact that processes of dislocation-structure relaxation have no time to occur during the ECAP at high pressing speeds.     

Evolution of misorientation spectrum of grain boundaries of submicrocrystalline molybdenum upon deformation under conditions of grain-boundary diffusion of nickel

Comparative investigations of the concurrent evolution of the structure and the misorientation spectrum of grain boundaries of submicrocrystalline molybdenum have been performed upon free annealing and under the creep conditions at a temperature of 1023 K. It has been established that changes in the misorientation spectrum of grain boundaries of submicrocrystalline molybdenum upon annealing and creep are observed concurrently with boundary migration. The grain-boundary diffusion of nickel upon annealing leads to an increase in the fraction of grain boundaries of the special type with Σ17a in the grain-boundary ensemble of submicrocrystalline molybdenum. Under the creep conditions grain-boundary diffusion fluxes of nickel atoms favor transformation of low-angle boundaries into high-angle boundaries and growth in the angle of misorientation of the high-angle boundaries of submicrocrystalline molybdenum to 45°–60°.     

Calculation of the parameters of pulsed laser welding of thin sheets of aluminium alloys

One of the main advantages of the MIG/MAG process is its high productivity. In most of the applications, positive polarity is used, due to its greater arc stability, generation of less splatter and formation of weld beads with suitable geometry. However, in some applications, there is a need for greater production capacity than that offered by conventional MIG/MAG welding. In the literature, it is stated that negative polarity provides a higher fusion rate than positive, despite leading to a high level of splatter and unsuitable formation of the weld bead. Unfortunately, there is not much information available on the effects of the process variables in this polarity, much less justification for such. Therefore, this work is an attempt to try to understand the reason why there is a higher deposit rate in negative polarity, as well as the related effect on the geometry of the weld beads. To do this, comparative MIG/MAG welds were produced in both positive and negative polarities, using two compositions of shielding gases at two current values. The transfer mode and the behaviour of the arc were analysed by synchronized profiling. The geometric profile of the weld bead was evaluated by means of metallographic procedures. From the results, which disagree in part with the current literature, it was seen that both the transfer mode as well as the morphology and the appearance of the weld bead are dependent on the composition of the shielding gas. To explain the phenomena inherent in the greater fusion rate of wire in DC ? , the suggestion is that the fact that arc scales the sides of the wire in this polarity may be the governing factor.     

Conductivity of aqueous suspensions of alumosilicates

When studying the electrochemical properties of diluted suspensions of natural and modified bentonite, the correlation between the inductive component of the system’s resistance and the temperature has been established. It confirms the hypothesis on the presence of paramagnetic particles in the system, whose solubility decreases with the growth of the temperature. Active forms of oxygen, as generated in the near-electrode space, can be such particles. It is shown that, in model systems, hydrogen peroxide is formed in this space due to the reversible dissociative adsorption of oxygen on platinum in the presence of a suspension electrode with proton conductivity.     

Effect of dendritic segregation of manganese on growth rate of pearlite

Conclusions The growth of pearlite in the process of isothermal transformation of austenite decreases mainly in sections between branches rich in manganese.At 560°C the growth rate of pearlite within branches and between branches is almost identical.With an increase of the manganese concentration from 1.5 to 3.6% the difference in the growth rates of pearlite in branches and between branches increases 7–64 times at 560°C, which is due to the change in the segregation coefficient from 0.82 to 0.56.Institute of Ferrous Metallurgy, Dnepropetrovsk. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5, pp. 17–21, May, 1975.     

Peculiarities of polyaniline matrix synthesis in the presence of mixtures of different types of matrices and investigation of properties of formed interpolymer complexes

In the present work, the existence of a matrix domination effect in the formation process in polyaniline interpolymer complex solutions under aniline oxidation in the presence of rigid and flexible poly(amidosulfonic acid)s was demonstrated for the first time.     

Properties of radiothermoluminescence of polyethylene-fibroin composite

In the given work, results of research of radiothermoluminescense (RTL) and electret properties of HDPE and composites on its basis containing a polar organic additive distributed in the volume of natural silk fibroin up to 50% are presented. It is established that changes in the molecular structure of HDPE by introduction of natural silk fibroin into it and radiation modification are shown in changes in RTL spectra. Complex research of RTL and electret properties of HDPE + fibroin composites has shown that, by studying RTL spectra of composites, it is possible to predict formation of high electret states in them.     

板料拉延中的润滑

论述了板料拉延成形时的摩擦、磨损特征和润滑机理 ,探讨了拉延时润滑油的使用问题 ,为生产实际中润滑油的选择提供了理论根据和实用参考。     

Simulation of formation of surface roughness of corroding materials

The article discusses the process of heterogeneous corrosion using a 3D model of metal consisting of two uniformly intermixed phases destroyed at different rates. The model describes the decrease in the rate of corrosion and the increase in roughness, as well as the formed microrelief of corroded metal as a function of the exposure time. The theoretical equations are verified by computer experiments.     

焊丝含碳量对高强度钢焊缝性能的影响

报导了焊丝中含碳量在0.09～0.18％范围内时对45CrNiMoV高强度钢焊缝力学性能的影响。随焊丝中含碳量的增加,接头强度上升,焊缝韧性下降。     

Kinetics of dissolution of phases upon deformation of nanostructured metals and alloys

The kinetic features of dissolution of foreign inclusions in the bulk of nanostructured metals upon plastic deformation have been discussed. It has been shown that the rate of dissolution of inclusions substantially depends on the character of structural transformations in the subsystem of intercrystallite boundaries of nanomaterials. Equations that determine the kinetics of dissolution of chemical compounds of metals depending on the rate of structural transformations in intercrystallite boundaries upon deformation have been obtained. The behavior of the kinetic curves of dissolution has been described qualitatively. Numerical estimates of the time of dissolution of inclusions Fe₃C and Fe₂B in steels are given which are in satisfactory agreement with experimental data on the mechanical alloying of iron with nonmetals in ball planetary mills.     

柔性加工系统FMS的Web数据库开发

论述了建立制造企业网与Web数据库的必要性。分析了互联网络环境中柔性加工单元的制造模式。详细讨论了用JDBC编写Web数据库应用程序的原理。最后分析了Web数据库存在的安全防护问题     

钛铁矿烧结性能研究

将钛铁矿在氩气及空气气氛中不同温度下进行烧结。采用XRD及热分析研究了钛铁矿在不同温度下烧结后的相组成及质量变化。结果表明,在氩气气氛950℃下烧结后,钛铁矿的物相组成没有发生变化;在空气中不同温度烧结后,600～800℃较低温度区间,钛铁矿转变为热力学亚稳定的Fe2Ti3O9,950℃以上烧结时,钛铁矿转化为热力学稳定的Fe2TiO5。钛铁矿的晶体结构由烧结前的三方结构经低温烧结后转变为亚稳态六方晶系的Fe2Ti3O9,950℃以上烧结后,晶体结构转变为斜方晶系的Fe2TiO5。     

钽低温离子渗氮工艺参数对渗氮层物相的影响

利用组合的二次回归正交实验设计方案 ,对钽低温离子渗氮条件下 ,表面物相及固溶体中氮的含量随渗氮温度、气氛总压力和氢氮摩尔比的变化进行了系统研究。发现表面渗氮层由化合物Ta6N2 .57、超晶格TaN0 .1和固溶体相组成。氮在钽中的固溶度随气压、温度和氢摩尔分数的增加而增加 ,化合物和超晶格相含量随温度增加而增加 ,同时化合物相随氢摩尔分数增加有一个极大值 ,该极大值随温度增加而下降。     

On size effect of rate of corrosion of copper nanowire ensemble: Part 2. Size effect of rate of corrosion of copper in pyrophosphate solution

The corrosion of specimens of copper produced by electroplating on disc electrodes 10–500 μm in diameter from a pyrophosphate electrolyte is studied in this electrolyte (without added copper ions) using polarization curve measurements. It is found that the rate of corrosion of the microelectrodes with a radius of 5 μm is eight times higher than that of the microelectrodes with a radius of 25 μm; the measured rate of corrosion remains unchanged when varying the radius of the microelectrode in a range of 25–250 μm. It is shown that the process under investigation is corrosion with oxygen depolarization; the rate of reduction (of dissolved oxygen) increases eightfold when varying the radius of the microelectrode in a range of 5–25 μm. The experimental results are confirmed by the calculations of diffusion currents for the microelectrodes, which show that the size effect, i.e., an increase in the diffusion current density with decreasing area of the electrode surface, should be observed for electrodes with a radius less than 20–30 μm.     

船体厚板高效气电立焊焊接技术的研究

针对集装箱船设计与建造关键技术研究的厚板焊接技术焊接状况，研制开发高效气电立焊焊接技术及自动化焊接设备，实现了EH36级δ=60mm厚板立缝的一次焊接成形技术，对提高我国集装箱船设计与建造及各种铜结构厚板焊接制造施工工艺．提高焊接质量和生产率，减轻工人劳动强度具有重要意义．