铈、锂盐对铝阳极氧化膜的协同封闭作用

研究了铈、锂盐在铝阳极氧化膜封闭处理中的协同作用.场发射扫描电镜和X射线衍射谱对铈、锂盐协同封闭前后铝阳极氧化膜形貌和结构的研究结果表明，封闭后膜表面的孔洞消失，封闭产物分布均匀，封闭后膜仍然以非晶态形式存在.根据X射线光电子能谱的结果，封闭后的膜主要由含结晶水的Al2O3及铈、锂的混合氢氧化物组成，同时膜中还含有及封闭溶液组分中的一些阴离子.电化学阻抗谱的研究结果表明铈、锂盐协同封闭能够显著提高膜的耐蚀性能.在实验结果基础上，初步认为铈、锂盐封闭是通过生成结构紧密的封闭产物填充、覆盖膜孔，从而显著提高铝阳极氧化膜的耐蚀性能.     

河道施工降水引起的邻近建筑物沉降分析

通过对地基进行沉降计算, 对基础沉降进行实际观测, 将计算数值与观测数值进行对比分析. 结果表明: 施工降水是导致邻近建筑物沉降、开裂的原因; 邻近建筑物地基沉降的规律是离 施工降水现场由近至远逐渐减小; 采用设止水帷幕和回灌井联合控制地下水位下降是一种有 效的措施.     

Testing of nitrile rubber joints for a deep submergence vehicle

This paper describes an experimental study of the long term sealing performance of nitrile rubber joints on a manned deep ocean submersible operating down to 6000 m depths. An initial formulation showing large compression set is discussed first. Then results from long term laboratory testing of a second formulation, aged in water for 10 years, are presented. Much lower compression set and higher sealing forces are observed. Based on these results a testing methodology for the prediction of the long term sealing performance of nitrile O-rings is proposed. Results from laboratory tests are compared with those measured on joints aged for up to 10 years in service.     

High temperature thermal expansion of BaAl2Si2O8, CaAl2Si2O8, and Ca2Al2SiO7 studied by high-temperature X-ray diffraction (HT-XRD)

Sealing of components for high temperature applications with coefficients of linear thermal expansion (CTE) > 10·10⁻⁶ K⁻¹ can be achieved by glasses from which crystalline phases with high CTE are precipitated. Many sealing glasses also contain further components as e.g. aluminium and hence, not only the desired phase is crystallized, but also additional phases. For this purpose, high temperature XRD was performed in order to determine the CTE of BaAl₂Si₂O₈, CaAl₂Si₂O₈, and Ca₂Al₂SiO₇. In the case of BaAl₂Si₂O₈ and Ca₂AlSi₂O₇ the CTEs were 7.8·10⁻⁶/K and 7.9·10⁻⁶/K, respectively. In the case of CaAl₂Si₂O₈ the CTE is 4.4·10⁻⁶/K. Especially the formation of the latter phase should be avoided for a sealing material of high temperature fuel cells. Sintered specimens of the respective compounds were also characterized by dilatometry.     

Stator well flows in axial compressors

This paper reports a study of the flow conditions in spaces often found beneath the stationary blades of modern compressors – stator wells. The design of the stator wells in a modern high-pressure turbofan can be a limiting factor. This study shows good comparison with existing experimental data upon the pressures and velocities in related geometries. The deleterious effects upon machine performance of the flows between the stator well and the mainstream are considered. The purpose of this paper is to show that these effects, especially seal leakage, can be reduced by the incorporation of fins on the rotating component of the downstream well. This works by increasing the tangential velocity in this region, so reducing the pressure there and thus the inter-well leakage for a given radial clearance in the intermediate labyrinth seal and hence the outflow into the mainstream from the upstream well.     

Miniaturized Optical System for Detection of Ammonia Nitrogen in Water Based on Gas-Phase Colorimetry

A small-size gas-tight optical measuring system for detection of ammonia nitrogen in water was prepared based on gas-phase ammonia induced color change of the sensing element that was made by loading bromothymol blue (BTB) in a transparent porous glass fiber membrane. The gas-tight optical measuring system consists of a gas-testing and a liquid-sample chamber connected with each other by means of tubes and a mini-pump that cycles the gas between the two chambers. A 625-nm light emitting diode (LED), a photodetector and a sensing element were mounted in the gas-testing chamber for optical response to ammonia gas released from the water in the liquid-sample chamber. Release of ammonia gas was realized by alkalinizing the water sample with NaOH. Owing to the amount accumulation of ammonia gas in the sealing system, the ammonia nitrogen detection limit of the device can be very low. A small concentration of ammonia nitrogen, as low as 0.05 mg/L, was detected. The two linear-response ranges from 0.05 mg/L to 0.26 mg/L and from 0.26 mg/L to 2.62 mg/L were obtained. A relative standard deviation of ≤1% was determined by multiple measurements of the same sample.     

一种多元杜瓦引线结构和工艺研究

主要介绍了一种散状引线结构形式的探测器用杜瓦结构及密封封接工艺方法。通过寿命跟踪考核、高灵敏度检漏等各项性能检测,表明这一工艺先进可行并已达到实用化推广的水平。     

Electro‐osmotic surface effects generation in an electrokinetic‐based transport device: A comparison of RF and MW plasma generating sources

It is a common practice in insulator‐based dielectrophoretic separation to use and reuse PDMS‐constructed microdevice for an extended period of time while performing biological and technical replicate experiments. This is usually done to rule out any effects of device variation on separation efficiency. Ensuring that all experimental conditions remain the same is critical to the conclusion that can be drawn from such repeated experiments. One important contributing factor to the flow of materials within the device is electro‐osmotic velocity, which stems from the surface condition of the device construction materials. In this paper, we present an affordable microwave‐based (MESA‐Mgen) oxygen plasma cleaner developed for approximately less than $100 using readily obtainable parts from an average local hardware store with no specialized tools. This low‐cost room‐air microwave plasma generator was designed using an R‐4055, 400 W, 2450 MHz half‐pint household microwave oven (Sharp ® ) for exploring the possibility of sealing polydimethylsiloxane (PDMS) devices onto glass with minimal budgetary commitment. Microfluidic channels generated using MESA‐Mgen were evaluated for their electro‐osmotic velocities while factors including contact angles, storage‐solvent, half‐way hydrophobicity period were also explored with MESA‐Mgen, and the results were compared to those obtained from the commercially available plasma cleaner (COM‐PC). These outcomes revealed that the MESA‐Mgen induced hydrophilicity and ensured leak‐free sealing of PDMS substrates in a manner comparable with the COM‐PC.     

Self-cleaning effect of sealing caps for infrared hollow fiber delivering pulsed Er:YAG laser light

A sealing cap had been proposed as an output device for hollow optical fibers in delivering laser light underwater. Properties of sealing cap were experimentally discussed when used in ablation on soft tissue for Er:YAG laser. A self-cleaning effect of the sealing cap was observed when various targets were used for different laser light power. Debris from pork fat formed a uniform oil layer on the output surface of the cap, and the oil layer is relatively transparent in Er:YAG laser light wavelength band. When the target was pork muscle, almost no debris could attach on the surface of the cap. The self-cleaning effect was more obvious when ablation was conducted underwater because of the protection of the water film between the target and the cap's surface.