Effect of grease type on abnormal vibration of ball bearing

The abnormal vibration of ball bearings lubricated with grease was studied. The test bearings were lubricated with three types of grease: Li soap/silicone oil grease, Na soap/mineral oil grease and Li soap/mineral oil grease. In the experiments, the axial-loaded ball bearings were operated at a constant rotational speed, and the vibration and the outer ring temperatures of the test bearings were measured. In addition, the shear stress and shear rate of the greases were measured by a rheometer. The experimental results showed that the abnormal vibration occurs on the test bearings lubricated with all three types of grease. Based on the experimental results, the generating mechanisms of the abnormal vibrations were discussed. From the discussions, it seems reasonable to conclude: (1) Li soap/silicone oil grease and Na soap/mineral oil grease both have a negative damping moment characteristic. The abnormal vibrations of the ball bearings lubricated with these greases are generated by the negative damping moment. (2) The abnormal vibration of the ball bearings lubricated with Li soap/mineral oil grease is generated by the decreasing positive damping moment of the grease due to the rising temperature.     

Surface Enhanced Raman Scattering on Self-assembled Nano Silver Film Prepared by Electrolysis Method

用一种廉价的电解方法制备了纳米银膜,并详细研究了在这种银膜上的表面增强拉曼散射效果．结晶紫为本实验的检测性分子．通过实验发现,这种银膜用便携式拉曼光谱仪测试并计算出的表面增强拉曼散射的增强因子为603,并对结晶紫的最小检出限为0.1 nmol/L     

布谷鸟搜索的润滑脂特征红外光谱波段优选技术

针对润滑脂分类,提出了基于布谷鸟搜索的红外光谱波段筛选方法,有效剔除了易受噪声等环境影响的红外光谱区域、实现了对庞大光谱数据进行特征选择和降维处理、通过筛选光谱最优波段建立了更加准确高效的润滑脂分类模型。以三类不同稠化剂润滑脂的红外光谱数据为研究对象,采用主成分分析法(PCA),对不同波段的红外光谱数据进行压缩,以提取的红外光谱主要成分作为输入,润滑脂稠化剂类别作为输出,通过布谷鸟搜索法(CS),对主要成分权重和分类核参数进行准确度寻优训练,建立分类识别预测模型。对所建立的模型再进行分类准确性测试,得到模型测试结果准确度,建立红外光谱波段和测试准确度之间的联系,得到润滑脂最优类别识别模型和最优分类波段。对所建立的模型再进行分类准确性测试,结果显示：经过布谷鸟搜索法训练加权后的主要特征呈现明显聚类现象,可以得到分类核,实现对润滑脂种类的准确识别;在搜索过程中提供了区分不同润滑脂的推荐波段和特征峰,使对润滑脂的正确鉴别概率由全波段建立分类模型的94.44%提高到筛选后特征波段建立分类模型的100%,并减少了运算时间、提高了搜索运行效率。     

孔雀石绿在自组装纳米银膜上的SERS

电解法制备了自组装纳米银膜。用紫外可见分光光度计和透射电镜对电解出的银胶进行了观测,并且用扫描电镜对制备好的银膜进行了表征,发现银膜上的纳米银颗粒是银胶中颗粒的二聚体和三聚体。我们得到了孔雀石绿的SERS谱,发现自组装纳米银膜对于用SERS检测孔雀石绿具有很好的增强效果,检测的下限是10-10M。另外,我们对所测不同浓度的孔雀石绿的指纹峰面积进行了分析,发现峰面积随浓度的变化有很好的线性关系,这对以后进行定量分析打下了基础。本实验说明用电解法制备的自组装纳米银膜对于检测孔雀石绿具有很好的应用前景。     

氯霉素在电解法制备纳米银膜上的表面增强拉曼光谱的研究

用电解法制备了一种纳米银膜, 并用扫描电镜和透射电镜进行了研究。我们得到了银膜上的氯霉素的SERS谱, 并且用gaussian’98软件对氯霉素的Raman谱进行了运算, 发现实验结果和理论计算结果有很好的相似性。本实验说明电解法制备的纳米银膜对于检测氯霉素有很好的应用前景。     

Hydrogen-induced degradation in strontium titanate single crystals

Hydrogen-induced degradation in strontium titanate single crystals was studied through an electrochemical hydrogen charging process, in which the silver electrodes of the crystals were made a cathode in 0.01 M NaOH solution to evolve hydrogen by electrolysis of water. After the process, the resistance of the crystals was decreased by more than one order of magnitude, the dielectric loss was obviously increased, and the capacitance became more dependent on frequency. It is proposed that atomic hydrogen generated by electrolysis of water diffuses into the crystals and exists as a charged interstitial impurity donating electrons to the conduction band of the crystals. Attention should be paid to this hydrogen-induced degradation when the reliability of perovskite-type ferroelectric devices and components is studied. PACS 77.22.Ch; 77.22.Gm; 77.84.Bw     

The rhombohedral-cubic transition in the IV-VI semiconductor GeTe under high pressure

Abstract

The IV-VI semiconductor GeTe was studied at room temperature as a function of pressure in a truly hydrostatic medium up to 8 GPa and in a quasi-hydrostatic environment, silicone grease, up to 25 GPa     

大气常压等离子射流清洗溶胶-凝胶SiO_2膜表面油脂污染物

采用大气常压等离子射流技术对溶胶-凝胶SiO2膜表面的油脂污染物进行清洗。利用分光光度计、扫描电子显微镜、红外光谱仪对溶胶-凝胶SiO2膜透过率、表面形貌、化学结构进行表征,并分析清洗前后溶胶-凝胶SiO2膜的激光损伤阈值变化。损伤阈值测试表明,1064nm波长的激光损伤阈值由污染后的16.08J/cm2上升到24.41J/cm2,与污染前24.72J/cm2的损伤阈值相当。同时还获取清洗的最佳时间为10s。清洗前后,溶胶-凝胶SiO2膜保持完好,且未产生新的有机污染物。研究结果表明:大气常压等离子射流技术可对溶胶-凝胶SiO2膜表面的油脂污染物进行有效地清洗,从而提高溶胶-凝胶SiO2膜的透过率和激光损伤阈值,为高功率激光装置的稳定运行提供保障。     

某印染废水的水质指纹特征

水质指纹携带了水样的发光有机物组成的信息,可以作为一种新方法来弥补COD和TOC等传统理化参数只能给出有机物总量信息的不足。印染废水是我国水量最大的工业废水之一,其特点是水量大、污染重,含有大量发光有机物质,且难降解,其对自然水体的危害尤为明显。对我国某印染废水处理厂废水进行了连续采样,对水样的水质指纹特征进行了研究。结果表明,该厂印染废水水质指纹特征比较明显,水质指纹上主要有激发波长/发射波长分别为230/340和280/310 nm左右的两个峰,其中230/340 nm处的强度最强,280/310 nm处的强度次之,各峰波长和强度比较稳定。该印染废水的两个水纹峰的峰强呈正相关关系,线性相关系数为0.910 8,斜率为1.506。激发波长/发射波长为280/310 nm的强度与230/340 nm强度比值的平均值为0.777,范围为0.712～0.829。对该印染污水水质指纹的可能荧光物质进行分析,结果表明生活污水和苯胺类物质的水质指纹与该印染污水的水质指纹不同,而几种大量使用的染料的水质指纹与该印染污水的水质指纹大致相同,所以染料的大量使用可能是导致印染废水产生上述典型水质指纹特征的主要原因。水质指纹可以用于水体水质预警。     

The application of high frequency ultrasound waves to remove ammonia from simulated industrial wastewater

This article aims at applying the ultrasound technique in the field of clean technology to protect environment. The principle of ultrasound was conducted here to remove and recover ammonia from industrial wastewater. Three different concentrations of ammonia namely 5%, 15% and 25% (vol.%) were used to study the efficiency of removing ammonia from water. These concentrations are exactly similar to what may be found in wastewater resulting from strippers at petroleum refinery. High ultrasound frequency device with 2.4 and 1.7 MHz was conducted to study the effect of waves on the removal of ammonia. It was found that the ultrasound has the ability to remove ammonia with 5% concentration to meet the local standard of treated wastewater within less than 2 h for 0.080 L solution. It was also found that as the concentration of the ammonia increases the removing of ammonia within 2 h decreases, still the concentration of the ammonia meets the standard of the treated wastewater. The ability of the ultrasound to remove the ammonia failed to produce any mist when the height of the liquid solution increased, namely when the height reached (0.0337 m). This is equivalent to liquid volume of 0.150 L. It means that the device capacity to remove ammonia has certain limitations based on liquid heights. The best condition for ammonia removal was obtained at 5% concentration and 0.080 L liquid volume (equivalent to 0.0165 m).     

The development and evaluation of electrolysis in conjunction with power ultrasound for the disinfection of bacterial suspensions

There is an increasing incidence in health problems related to environmental issues that originate from inadequate treatment of potable waters. This has compelled scientists and engineers to engage in innovative technologies to achieve a maximum disinfection at affordable costs. Some species of bacteria produce colonies and spores that can agglomerate in spherical clusters and thus protect organisms on the inside of the cluster against biocidal attack. Flocs of fine particles (e.g., clay) can entrap bacteria and this can also protect them against the biocides. Other bacteria have the ability to mutate, thus building up resistance to conventional biocides (e.g., chlorine).Ultrasound has been shown to be effective in improving the effectiveness of biocides such as chlorine. The aim of this present study was to investigate the effect of electrolysis and power ultrasound as a disinfection treatment and to provide a greater knowledge of the fundamentals of disinfection through the production of hypochlorite in situ from saline solution via electrolysis. The electrode materials investigated were, carbon (felt and graphite), copper and stainless steel rods. The results show that sonication appears to amplify the effect of electrolysis. A combination of both treatments is significantly better than sonication or electrolysis alone.     

Treatment of petroleum refinery wastewater by ultrasound-dispersed nanoscale zero-valent iron particles

Petroleum refineries release wastewater, which is rich in organic pollutants and cannot be treated easily. This study presents the treatment of petroleum refinery wastewater using nanoscale zero valent iron (NZVI) in the presence of ultrasonication. NZVI characteristics were analyzed using SEM and XRD. The influence of NZVI dosage and initial pH on % chemical oxygen demand (COD) reduction was studied. From the results, it can be inferred that a dosage of 0.15 g/l and an initial pH are optimum for the effective degradation of effluents. The degradation data were found to follow first order kinetics. The results indicate that using NZVI in combination with ultrasonication is an efficient method for the treatment of petroleum refinery wastewater.     

射线检测管道垢厚方法的研究进展

报告了我国开展射线检测原油管道垢厚的研究进展. 介绍了γ射线透射检测垢厚的基本原理、 模拟实验装置及主要研究成果. 研究表明, 研制透射型测垢仪是可行的. 另外, 还给出了南京大学关于表面型中子测垢仪和γ射线测垢仪的初步预研结果.     

日光/Fenton法处理油田废水的机理

研究了日光/Fenton法对辽河油田采油废水处理效果,并分析了日光/Fenton法好于普通Fenton法的原因。辽河油田采油废水主要含有苯类和烷烃类化合物,日光/Fenton法对辽河油田采油废水处理效果与废水水层高度相关,水层高度升高,COD去除率降低,日光对本油田废水的穿透能力在1 m左右。废水水层高度为40 cm左右时,采油废水经日光/Fenton法处理后,COD由430降至63.2 mg·L-1。通过紫外可见光谱法、红外光谱法(FTIR)及X射线衍射法证明了利用日光/Fenton法处理辽河油田采油废水时体系中有聚铁生成,聚铁的形态与普通Fenton体系生成的聚铁基本相同。同时利用紫外光谱法研究了苯类及烷烃类的转化方式,结果表明： 烷烃类在日光/Fenton和Fenton体系中的转化方式基本相同;而苯类在日光/Fenton体系中的羟自由基作用下转化成具有光敏性的物质。芳香族中间产物的光敏性是日光/Fenton法比普通Fenton法高效的原因。     

黄铁矿处理重金属废水的光谱表征

将反射光谱和吸收光谱用于黄铁矿处理酸性重金属废水的研究,探讨了黄铁矿的表面反应以及黄铁矿与重金属的相互作用。漫反射红外光谱分析证实,在处理废水过程中,黄铁矿中表面羟基与重金属离子发生反应;并通过考察黄铁矿中碳酸盐,合理解释了黄铁矿处理酸性重金属废水后的溶液自然均趋于中性(pH 7)的现象。可见区的反射光谱用于表征处理过程中的黄铁矿的颗粒及比表面变化,解释了黄铁矿在重复使用时其活性反而增强的原因。吸收光谱及XPS表征表明,黄铁矿处理含Cr(Ⅵ)废水,是一个由Cr(Ⅵ)到Cr3+再到Cr(OH)₃的吸附沉淀过程。     

Carbon nanotube grease with enhanced thermal and electrical conductivities

A stable and homogeneous grease based on carbon nanotubes (CNTs, single-wall and multi-wall) in polyalphaolefin oil has been produced without using a chemical surfactant. For example, for a 11 wt% (7 vol%) single-wall CNT (diameter 1–2 nm, length 0.5–40 μm) loading, the thermal conductivity (TC) of the grease shows a 60–70% increase compared to that for no nanotube loading. In addition, the grease is electrically conductive, has a high dropping point, good temperature resistance, and does not react with copper at temperatures up to 177 °C. The performance of carbon nanotube grease could be much better with the improvement of nanotube quality and purity. A possible explanation for these results is that of a high loading of CNTs (>10 wt%), they become associated with each other by van der Waals forces in the grease to form three-dimensional percolation networks. Time-dependent magnetic results demonstrate that, even under the influence of a strong outside magnetic field, the TC value remains constant. This phenomenon can be attributed to the existence of networks that makes magnetic alignment of nanotubes impossible.     

Comparative interaction mechanisms for different laser systems with selected materials on titanium alloys

This paper describes further research into, and modelling of, the interaction mechanisms of various laser types with materials, including synthetic oil and silicone grease. A Q-switched Nd:YAG pulsed laser, a CW CO₂ laser, and a pulsed KrF excimer laser (λ = 248 nm) were used in the study. In general, the materials studied were very absorptive in the ultraviolet, less absorptive in the infrared, and least absorptive in the near-infrared. For the excimer, photo-ablation takes place, while for the other two wavelengths thermal vapourization dominates. In the case of silicone grease, full volatilization is only obtained using the excimer. For the other two wavelengths, this is not the case, with a sticky residue remaining after treatment. Interaction with synthetic oil with its lower boiling point can be obtained for all three laser types. With the Nd:YAG the dominant heating mechanism is conduction from the substrate and a baking effect is observed with strong interaction between the contaminant and the substrate. For the two pulsed lasers, oxidation is substantially less, while for the continuous wave CO₂, the interaction time is sufficiently long for oxidation and secondary reactions to take place if care is not taken to work below the reaction threshold.     

The crystal change and "excess heat" produced by long time electrolysis of heavy water with titanium cathode

According to the theory given in the paper[1], the long time electrolysis experiment with titanium cathode in heavy water (D2O) were done for many times by using the open-loop multi-parameters electrolysis calorimetry system, which is established by us. The specialty is that the cathode is titanium rod and the anode is platinum wire. The early experiment result[3] is still repeated in our recent experiment. The obvious "excess heat" phenomenon can take place only when the electrolysis last more than ten days and amount of "excess heat" increased with the electrolysis time. The "excess heat" can also be obtained from the "boiling to dry" experiment. In the recent experiment, we obtain the results that the amount of "excess heat" is about 3.6 times the input energy, the "excess heat" power is 76.5 W, and the "excess heat" power density is 121.7 W/cm3. After the electrolysis, the crystal structure of the Ti cathode was measured with x-ray diffraction apparatus. We found that the crystal structure of Ti cathode was changed to face-centered cubic structure of TiD2 from its hexagonal structure. This result is in agreement with the Gou's theory mentioned in reference[1].     

硫酸甲醇体系中钽的电解动力学

 为了探索钽的电解动力学行为,在硫酸甲醇电解液中对钽进行了电解抛光的实验研究,测定了电解液配比、电压、搅拌速率对钽薄膜减薄速率的影响;通过测定温度对反应速率的影响,计算了阿仑尼乌斯（S.A.Arrhenius）活化能。研究结果表明：温度在0 ℃,硫酸甲醇体积比为1∶7时,钽的电解行为符合典型金属极化行为规律;在电压10~20 V的范围内,搅拌速率大于8 m/s时,减薄速率稳定为11.45 μm/min;当搅拌速率小于8 m/s时,扩散传质控制电解过程,当大于8 m/s后,电解过程为非扩散控制。温度对反应速率的影响表明,钽在硫酸甲醇电解液中的电解行为符合S.A.Arrhenius公式,活化能为15.77 kJ·mol^-1。     

碳纳米管与石墨烯协同提高导热硅脂热性能

以甲基硅油为基础油,碳纳米管、石墨烯或碳纳米管/石墨烯混杂物为导热填料,制备复合导热硅脂.研究结果表明:以碳纳米管为单一导热填料,碳纳米管管径越小,管长越长,越有利于导热硅脂的导热性能提升。当总填充量在6%、碳纳米管和石墨烯配比为2:1时,导热硅脂的热导率提高19%。碳纳米管对石墨烯纳米片起到了分隔和桥连的作用,提高了石墨烯纳米片的分散性,有利于三维热传导网络的形成,进而提高导热硅脂的热传导性能。