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。     

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。     

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.     

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.     

Mechanism of improvement of formability in pulsating hydroforming of tubes

The mechanism of improvement of formability by the oscillation of internal pressure in a pulsating hydroforming process of tubes was examined. Free bulging hydroforming experiments of mild steel tubes under oscillating and constant inner pressures were performed. For a high constant pressure, a round bulge with local thinning was observed, whereas wrinkling occurred for a low constant pressure. The occurrence of these defects was prevented by oscillating the internal pressure in the pulsating hydroforming. In the pulsating hydroforming, a uniform expansion in the bulging region was obtained, and thus the formability was improved by preventing the local thinning. It was found from an observation of deformation behaviour, using a video camera, that the tube is uniformly expanded by repeating the appearance and disappearance of small wrinkling. The cause of the uniform expansion for the pulsating hydroforming was also interpreted from the variation of stress components. In addition, a similar deference in deformation behaviour between the oscillating and constant inner pressures was also obtained in finite element simulation.     

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°.     

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.     

The assessment of the value of GPR imaging of flexible pavements

A survey of the different applications of ground penetrating radar (GPR) for highway pavement investigation is presented with a critical appraisal of the success with which it was applied. The problems associated with this technique are also discussed. These include discussions of the accuracy of the technique and the difficulties in trying to interpret the recorded signals. Suggestions for the future direction of the research in this field to enhance the data collection and interpretation are made. The remainder of this paper investigates the advances that can be made in the use of existing GPR technology in the field of thin pavements investigation.     

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。     

Inhibition of copper corrosion by coatings of alkyl esters of carboxybenzotriazole

The inhibitive effect of coatings formed dipping copper in solutions of alkyl esters (methyl, butyl, hexyl and octyl) of carboxybenzotriazole was studied by potentiodynamic polarisation, electrical impedance spectroscopy, coulometry and surface enhanced Raman scattering (SERS) spectroscopy. The inhibition efficiency of the dry film depends on type of solvent used in the coating solution, temperature and period of immersion. Pretreatment by immersing copper in hot (70 °C) aqueous solution (1×10⁻⁴ M) for approximately 2-3 h gave a film with the highest degree of corrosion protection. Higher temperatures or longer time of immersion reduce the protectiveness of the film. Copper coated using either alcohol or acetone as solvent was less well protected than when dipped in aqueous solution. Impedance spectra showed that the film formed by pretreatment in aqueous solution of inhibitors can be stable in acidic sulphate corrodent (pH∼0) for up to 3 days before breaking down. In near-neutral sulphate solution (pH∼8) the film can be stable for up to 10 days. In both acidic and neutral sulphate solution, the inhibition efficiencies of the protective film increased with the length of the alkyl ester chain in the order: methyl < butyl < hexyl < octyl. This is different to the behaviour of copper in a near-neutral aqueous corrodent containing dissolved inhibitor. The ester films also exhibit anti-tarnishing properties in a sulphidising environment with inhibition efficiencies increasing as the alkyl chain is made longer. Again the films formed by pretreatment in aqueous solution have superior anti-corrosion properties compared to those formed by pretreatment in either alcohol or acetone solution. SERS measurements indicate that the azole ring is close to the copper surface with chemisorption through azole nitrogen. It is also suggested that the hydrocarbon chain of the ester is physically adsorbed on the copper.     

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。     

Question of the mechanism of formation of the damping condition of high-chromium ferritic steels

Conclusions Damping in high-chromium ferritic steels is formed primarily as the result of magnetoelastic dispersion of energy, the level of which is determined by the character of interaction of the magnetic domain boundaries moving in the field of applied cyclic stresses with some subsystems of stoppers, defects of the crystalline structure. The maximum in damping capacity of Kh16, Kh16M4, and Kh25 steels is observed after annealing at 900–1000°C and is the result of superposition of individual oppositely acting on the magnetic constituent of damping contributions during evolution of structural defects under different temperature-time actions. An analysis of the contribution of different crystalline lattice defects makes it possible to predict the path of formation of the controlled level of vibration absorbing properties of high-chromium steels. The high-damping condition is characterized by a low level of internal stresses, moderate values of coercive force, and non-linearity of the elastic properties under the action of external stresses. The damping capacity after annealing in the temperature area of stratification of high-chromium ferrite and appearance of 475°-brittleness is determined by the action of two primary tendencies, the reduction of internal stresses as the result of ecomposition of the supersaturated solid solution of interstitial impurities and the subsequent increase in them as the result of stratification of high-chromium ferrite and formation of zones enriched with chromium.Moscow Institute of the Physics of Metals. Kharkov State University. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 9, pp. 29–34, September, 1993.     

Development of the technology of ultrasonic welding of components made of Capron tapes

The technology of ultrasonic welding of components made of Capron tapes producing welded joints with high strength parameters has been developed. The numerical values of the main parameters of the conditions of ultrasonic welding of the Capron tapes are determined. It is shown that the increase in the amplitude and welding pressure shortens the welding time. The experimental results show that the Capron tapes are characterized by geometrical homogeneity in both the transverse and longitudinal direction so that the welded joints can be produced both along and across the tape.     

高等教育国际化与中国高等教育施化力培育

本文从化层、化型、化向与化力等方面考察高等教育国际化的应然本质属性 ,描述与分析中国高等教育在国际化潮流中表现出的发展态势 ,针对种种态势提出中国高等教育核心施化力培育战略 ,以使中国高等教育乃至世界高等教育真正地走向国际化     

Characteristic Features of the Kinetics of Decomposition of Supercooled Austenite of Alloy Steels in the Pearlite Range

The kinetics of decomposition of supercooled austenite of medium-carbon Cr – Ni – Mo steels in the pearlite range is studied by dilatometric and metallographic methods with computer processing of the data. It is shown that the rate of the decomposition of supercooled austenite in the pearlite range oscillates with a low amplitude. The changes in the exponent in the Avrami and Ostin – Rikket equations that describe the decomposition of supercooled austenite are associated with simultaneous processes of austenitic transformation whose kinetics differs substantially in local regions of the metal, which is mainly connected with the polymodal nature of the grain structure of the austenite.     

ULCB钢焊接熔池凝固过程数值模拟

采用元胞自动机法建立ULCB钢焊接熔池凝固过程的宏微观耦合模型,模拟非均匀温度场下焊接熔池凝固过程的组织形貌演变和溶质场分布,分析不同形核参数和合金成分对焊接熔池枝晶形貌的影响。结果表明,熔池边缘形成柱状晶,熔池中心形成等轴晶,柱状晶和等轴晶相互抑制长大;枝晶生长过程中始终存在着枝晶偏析现象;形核密度和合金成分影响枝晶的形核和生长,随着形核密度和合金成分的增加,焊缝中等轴晶区域增加,晶粒细化。     

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.