A new and fast method to determine mixing and conductive cooling of thermal waters in carbonate-evaporite environments

A method is proposed, for low-temperature geothermal systems, for calculating the aquifer temperature and relative proportions of mixed thermal and shallow groundwaters from carbonate-evaporite environments. The fluid is assumed to be in chemical equilibrium with anhydrite and chalcedony in the aquifer, and mixed with diluted waters during its ascent. An attempt has been made to establish a relationship between reservoir temperature, the aqueous sulfate and silica contents of the mixed fluid, the proportion of the thermal end-member and the temperature of the adiabatic mixture. The method calculates mineral solubilities in the field context, calibrated on representative thermal springs. The method also considers the effects of conductive cooling.     

高性能硅橡胶按键的制造

本文介绍一种高性能硅橡胶按键的制造方法和质量控制参数，详细叙述绝缘胶料和导电胶料的配方及性能，研制的硅橡胶按键经３２万次寿命试验，产品仍然完好；标准接触电阻小于１００Ω；绝缘电阻值大于１×１０＾１６Ω－ｃｍ；手感优异，反弹性良好，符合硅橡胶按键的要求。     

Two-dimensional thermal analysis of a polygonal fin with two tubes on a square pitch

The boundary element method (BEM) has been used to investigate the two-dimensional temperature distribution and the flow of heat from a polygonal fin with two tubes on a square pitch. This numerical method is shown to be convergent, stable and consistent. The resultant heat flows from the fin and the tubes are presented in the form of fin performance ratios. The values of the two-dimensional fin performance ratios are almost identical to those obtained for a single radial rectangular fin of equivalent surface area. The one-dimensional fin performance indicators, fin performance ratio or fin efficiency can be used to predict the heat flows. However, the two-dimensional temperature distributions have revealed the existence of conductive paths between the two tubes depending upon the fin dimensions, the values of the heat transfer and material thermal conductivity, and the magnitude of the temperature differences between the two tubes and the surrounding air.     

喷镀法制备SnO2膜导电玻璃的研究

用喷镀法将 Sn Cl4溶液喷射到预先加热的玻璃表面 ,制成了薄膜电阻 <70 Ω/□ ,透光率 >88% ,热稳定性 <45 %的 Sn O2 膜导电玻璃 ,研究了膜厚、基底温度、溶液组成对薄膜电阻与透光率的影响。     

用STM的纳米导电图形加工技术的研究

用STM针尖对有机络合物电双稳薄膜材料施加强电场作用 ,可在材料表面产生纳米线度的导电几何图形。实验证明 :对针尖本身的几何构形、施加在针尖上的脉冲幅度、周期和占空比都必须进行细致的选择。用Ag TCNQ络合物进行实验 ,在适合的针尖 样品距离下 ,发现所加脉冲偏压的极性为负时 ,容易进行加工     

Short poly(phenylene vinylene) chains grafted poly(organophosphazene)

Brominated poly(bis(4-methylphenoxyphosphazene) was allowed to react with 1,4-bischloromethylbenzene or 1,4-bischloromethyl-2,5-dimethoxybenzene in solution using phase transfer catalyst or potassium t-butoxide. Poly(p-phenylene vinylene) or poly(2,5-methoxy-1,4-phenylene vinylene) grafted organophosphazene copolymers were obtained. The UV-Vis absorption, photoluminescent, and thermal properties of the copolymers were measured. The copolymers are complete soluble in common organic solvents and fluoresce in the blue color range. The copolymers were used to build a series of organic light emitting diode (OLED). Only weak to nominated intensities with emission color from blue to red were obtained. The photoluminescent and electroluminescent (EL) spectra indicated there is a distribution in the PPV conjugated length. The compositions of the copolymers before and after the graft reaction were analyzed using NMR.     

The irreversibility of dimensional changes in epoxy adhesives undergoing uptake and expulsion of water

An optical interference method, developed to measure swelling inhomogeneities during water uptake by epoxy-based adhesive films¹, has now been used to study the extent of dimensional recovery during subsequent removal of the water responsible for swelling. A microscope cover slip is employed as marker to evaluate displacements normal to a resin film that is sandwiched between it and a rigid substrate. By placing an optical flat close to the free surface of the cover slip, a cavity is created within which optical interference can occur between light incident upon and light reflected from the specimen. Normal displacements in the resin cause similar displacements in the cover slip, i.e. the geometry of the cavity is altered, and this produces changes in the pattern of interference fringes. It is found that repeated exposure of the specimen to both wet and dry environments (distilled water at 62°C and dry air at 62°C) leads to reversible changes in the displacement field normal to the adhesive film when the exposure is relatively modest (～ 1 day at 62°C), but that prolonged exposure (> 2 days at 62°C) produces irreversible changes.     

Conductive Materials for Proton Exchange Membrane Fuel Cell Bipolar Plates Made from PVDF,PET and Co‐continuous PVDF/PET Filled with Carbon Additives

The aim of this work was to develop and characterise electrically conductive materials for proton exchange membrane fuel cells and bipolar plates (BPPs). These BPPs were made from highly conductive blends of polyethylene terephthalate (PET) and polyvinylidene fluoride (PVDF), as matrix phase. The conductive materials were developed from carefully formulated blends composed of conductive carbon black (CB) powder and, in some cases, graphite synthetic flakes mixed with pure PET, PVDF or with PVDF/PET systems. They were first developed by twin‐screw extrusion process then compression‐molded to give BPP final shape. As the developed blends have to meet properties suitable for BPP applications, they were characterised for their rheological properties, electrical through‐plane resistivity (the inverse of conductivity), oxygen permeability, flexural and impact properties. Results showed that lower resistivity was obtained with PVDF/CB blends due to the higher interfacial energy between the PVDF matrix and CB and also the higher density and crystallinity of PVDF, compared to those of PET. It was also observed that the lowest resistivity values were obtained with mixing PVDF and PET at controlled compositions to ensure PVDF/PET co‐continuous morphology. Also, slow cooling rates helped to attain the lowest values of through‐plane resistivity for all studied blends. This behaviour was related to the higher crystallinity obtained with low cooling rates leading to smaller amorphous regions in which carbon particles are much more concentrated.     

LC电调带通滤波器的设计

本文采用桥接网络法设计了一个LC电调带通滤波器,1dB通带连续可调范围为：110～125MHz至110～155MHz、体积为25mm×13mm×7mm。对桥接网络法的椭圆类型滤波器做了深一层研究,找到了提高其矩形系数及带外抑制的改进方法。     

Monolayer and bilayer conducting polymer coatings for corrosion protection of steel in 1 M H2SO4 solution

In this study, monolayer polypyrrole (PPY), polyaniline (PANI), and bilayer PPY/PANI, PANI/PPY coatings were deposited onto steel electrodes by electropolymerization in 0.1 M monomer and 0.3 M oxalic acid solution. Such corrosion parameters of these electrodes, as corrosion potentials, anodic Tafel constants and corrosion current densities were determined by means of current–potential curves as a function of time in 1 M H₂SO₄ solution. These findings were compared to the corrosion parameters of a bare steel electrode in the same acid solution. The monolayer and bilayer polymer coatings were characterized by the Fourier transform infrared (FTIR) spectroscopy and SEM. Bilayer coatings displayed better corrosion inhibition efficiencies than monolayer coatings. Furthermore, the PPY/PANI coatings offered superior corrosion protection than the PANI/PPY coatings.