Assessment of spray quality from an external mix nozzle and its impact on SQL grinding performance

Spray quality is the critical factor which decides the efficacy of Small Quantity Lubrication (SQL) technology in a high specific energy involved machining process like grinding. Yet, the understanding about spray quality, the actual process mechanics and its effect on machining performance is inadequate. The present work is an attempt to establish a correlation between the spray input variables, quality of the spray and machining performance of SQL grinding through modelling and experiments. Using computational fluid dynamic techniques, the variation of droplet size, droplet velocity, number of droplets and heat transfer coefficient have been analysed at different input parameters and the computed trends have been verified and validated. CFD modelling of spray indicates that it is possible to produce aerosol medium with high heat dissipation ability at moderately high air pressure and low flow rate. It also shows that any increase in atomising air pressure favourably leads to notable increase in wetting area and also results in substantial enhancement in heat dissipation ability. Reduction of residual stress is thus remarkably good. On the other hand, grinding fluid flow rate, if increased, offers significantly better lubricity and reduces the grinding force which also reduces tensile residual stress. Short spell grinding test results are found to be in good agreement with CFD results.     

Nature of heterophase inclusions in high-purity optical fiber materials as studied with 3D laser ultramicroscopy

3D laser ultramicroscopy (3D LUM) is intended specially for determining the concentration and size distribution of submicron inclusions in the bulk samples of high-purity materials for visible and IR fiber optics. In this work the 3D LUM technique is shown to be able to identify the nature of individual inclusions detected. The measurement of the light scattered by an inclusion at a varied probe beam wavelength and polarization and at a varied scattered light collection angle makes it possible to determine the inclusion refractive index. The 3D LUM possibilities are illustrated by the example of studying the inclusion nature in the As₂S₃ glass samples prepared by the direct synthesis from elements in a quartz container at elevated temperatures.     

Fe3O4/PSt/TiO2多层包覆电磁响应微球的制备

首先采用分散聚合法将自制的Fe3O4磁流体和苯乙烯反应合成有磁核的Fe3O4/PSt磁性聚合物微球，然后，用非均匀成核水解反应在Fe3O4/PSt微球外包覆无定形二氧化钛，获得Fe3O4/PSt/TiO2复合微粒。用红外光谱、扫描电镜和热分析对粒子的形貌和结构进行了表征。并测试了微粒的介电性能和磁性，结果表明，所制得复合微粒有良好的电、磁响应性。     

Synthesis,characterization and ion exchange properties of zirconium(IV) tungstoiodophosphate,a new cation exchanger

Zirconium(IV) tungstoiodophosphate has been synthesized under a variety of conditions. The most chemically and thermally stable sample is prepared by adding a mixture of aqueous solutions of 0·5 mol L⁻¹ sodium tungstate, potassium iodate and 1 mol L⁻¹ orthophosphoric acid to aqueous solution of 0·1 mol L⁻¹ zirconium(IV) oxychloride. Its ion exchange capacity for Na⁺ and K⁺ was found to be 2·20 and 2·35 meq g⁻¹ dry exchanger, respectively. The material has been characterized on the basis of chemical composition, pH titration, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis. The effect on the exchange capacity of drying the exchanger at different temperatures has been studied. The analytical importance of the material has been established by quantitative separation of Pb²⁺ from other metal ions.     

Stability of hydrogenated nanodiamonds under extreme ultraviolet irradiation

It is generally accepted that diamond is resistant to a wide spectrum of electromagnetic radiation from the ultraviolet through to the soft X-ray range, which makes it very attractive for the fabrication of diamond-based photodetectors. However the effect of photon radiation on the diamond structure has not yet been examined. In the work presented here, photoelectron spectroscopy has been used to study the graphitization of nanodiamond crystallites exposed to extreme ultraviolet radiation. Under such irradiation, the surface hydrogen groups and graphite species are found to prevent graphitization. The mechanism of radiation-induced nanodiamond graphitization is discussed.     

Passivation effects of deuterium exposure on boron-doped CVD homoepitaxial diamond

The deuterium (hydrogen) passivation effect on acceptors in boron-doped CVD homoepitaxial diamond was studied by electrical (Hall-effect) and secondary ion mass spectroscopy (SIMS) measurements. Deuterium was incorporated into the samples using microwave (MW) deuterium plasma at 673 K for 2–24 h. We observed the progress of acceptor passivation with p-type conduction, which finally resulted in a highly resistive state.     

刚性棒状全芳香液晶聚酯的合成及性质的研究

以溴和苯基取代的对苯二甲酰氯及2，2′-二甲基联苯-4，4′-二甲酰氯作为单体，分别与甲基、叔丁基、苯基取代的对苯二酚经熔融缩聚反应，合成一类具有刚性棒状结构的全芳香液晶聚酯。聚酯的热性质以TGA、DSC，热台偏光显微镜研究。所有的聚酯均为热致性液晶，它们具有相对较低的转变温度，在普通的有机溶剂中具有较好的溶解性质。     

微型构造表征技术在八面河油田的应用

通过对八面河油田井网密集区及井网稀疏的欠开发区的微构造研究,探讨了微构造表征技术。首先在储层多层次逐级对比的基础上,建立主力油层对比关系;密集井网条件下,则利用钻井资料编制油层顶底微型构造图;对于欠开发地区,通过人机联作自动追踪成图技术,输出2m等值线间隔构造图,建立微构造模型。以微构造模型为基础进行潜力评价,部署关键井寻找优质储量或进行开发动态调整。应用该项技术在八面河油田滚动发现了角15块等断鼻翼部局部高点,增加石油地质储量488×10~4t。     

三维地质模型在濮城油田的应用

以濮城油田东区沙二下油藏为研究对象，在储层流动单元细分、微构造、沉积微相、测井曲线二次处理、储层非均质研究、储层动态解释等研究基础上，以数据库为支撑，应用三维可视化技术，建立了研究区油藏三维可视化地质模型。其成果应用于油藏的调整井位设计，并且实现了油藏精细描述—油藏精细数值模拟一体化，效果良好。     

Thermal Characterization of 1.3 μm InAsP/InGaAsP Ridge Waveguide MQW Lasers Based on Spectroscopy Method

An experimental way to analyze the thermal characterization of semiconductor lasers based on spectroscopy method under pulse driving conditions has been developed. By using this way the thermal characteristics of strain compensated 1.3 μm InAsP/InGaAsP ridge waveguide MQW laser diodes have been investigated. Results show that by measuring and analyzing the lasing spectra under appropriate driving parameters and temperature ranges, the thermal resistance of the laser diodes could be deduced easily. A higher thermal resistance of 640 K/W has been measured on a narrow ridge laser chip without soldering. Other thermal and spectral properties of the lasers have also been measured and discussed.