四川非常规气田开发主要钻井技术及其应用效果

随着油气勘探开发难度不断加大,尤其是近年来非常规气田的开发,定向钻井成为钻井主流技术,如何有效控制钻井成本和保护环境并防止井下事故的发生成为作业者必须面对的问题。为此,自2010年以来,在荷兰皇家壳牌集团(中国)四川非常规气项目50余井次的钻井工作中,运用了旋转导向技术、新型钻井液配方、钻井液回收技术和固控配套技术,取得了快速、安全、环保的应用效果,其中DXXX井应用旋转导向钻井,实现完钻井深5 729 m,水平段长1 418 m,钻井周期105 d,同比螺杆钻水平井节约时间65 d,钻井工程创下了该区新纪录。尤其是针对不同地层特点,兼顾环保要求,成功研制和应用了新型钻井液配方、固控和钻屑处理技术,取得了较好的环保效果。结论认为,上述配套技术的应用对提高钻遇产层成功率、提高钻井速度、缩短钻井周期、控制钻井成本、获得更好的经济效益和社会效益,具有重要的保障作用。     

Do phosphoric acid esters affect the immediate enamel bond strengths?

Purpose: To investigate the effects of phosphoric acid esters (PAEs)-containing primers on the micro-tensile bond strengths (MTBS) of etched enamel, the micro-morphologies of the resin–enamel interfaces, and the enamel surfaces.

Materials and Methods: Thirty-three bovine incisors were used in this study. After the labial enamel surfaces were highly polished, they were etched, water sprayed, and air-dried. Afterward, the enamel surfaces were treated with or without (control) one of three PAEs-containing primers (40%MDP, Ivoclar Vivadent; Resulcin AquaPrime A + B, DMG; Xeno V, Dentsply), water sprayed, and air-dried. Subsequently, an adhesive Heliobond (Ivoclar Vivadent) was applied and resin composite (Core Build-up, Bisco) was placed incrementally. They were prepared into multiple beams of about 1 × 1 × 8 mm for MTBS tests. The enamel surfaces and resin–enamel interfaces were analyzed by SEM and TEM. The data were analyzed by two-way ANOVA and LSD test.

Results: Using PAEs-containing primers could increase the enamel MTBS (p < 0.05). The primer MDP produced higher MTBS than the primer Resulcin AquaPrime A + B and Xeno V. The SEM findings revealed the primed enamel surfaces were covered with a thin or glue-like layer of monomer-calcium salts of PAEs and the residual enamel crystallites, and various micro-porosities were detected within the hybrid layers. The TEM findings revealed the hydroxyapatite crystallites were tightly covered by the adhesive, the adhesive mixed with resin composite, or sparse irregular enamel crystallites.

Conclusion: The application of PAEs-containing primers on the etched enamel substrate could significantly increase the immediate enamel bond strengths. However, this effect was dependent on the individual PAEs-containing primer used.     

Spectral and Laser Properties of Yb:LuAG Transparent Ceramics Fabricated by Tape Casting Method

Yb³⁺‐doped LuAG laser ceramics with different Yb³⁺‐doping concentrations were successfully fabricated by nonaqueous tape casting method and vacuum sintering technology. XRD patterns and SEM morphologies of the ceramics were presented. The optical in‐line transmittance of the Yb‐doped LuAG ceramics was about 83% at 1030 nm. The fluorescence lifetime of annealed and unannealed ceramic samples was compared. From the spectroscopic properties, it can be seen that the ceramics had a large emission cross section of 2.9 × 10^?20 cm² with a FWHM of about 7.2 nm at 1030 nm. Under 100% population inversion, the maximum gain coefficient was estimated to be 12.4 cm^?1 at 1030 nm. With a fiber‐coupled diode laser as pump source, CW laser at 1030 nm was demonstrated and the maximum output power of 338.9 mW was achieved with a slop efficiency of 19%. A tuning range from 1028 to 1036 nm was obtained.     

Facile fabrication of ultra-low density,high-surface-area,broadband antireflective carbon aerogels as ultra-black materials

Carbon aerogels with various densities, even as low as 20 mg/cm³, were fabricated by pyrolysis of organic aerogels formed by aqueous condensation of resorcinol and formaldehyde. It was found that carbon aerogels with the density below 70 mg/cm³ exhibited the total reflectance values of typically less than 0.24 % across wavelengths in the range of 400–2000 nm. The change of antireflective properties between the lowest-density carbon aerogel monolith and its powder coating was discussed. Furthermore, we studied the effect of the density on the structure and antireflective property of carbon aerogels. As a result, the low-density carbon aerogels showed broadband low-reflectivity and high absorption to incident light.     

厦门地铁车站基坑施工诱发地表沉降的经验#br# 预测方法研究

地铁建设的快速发展对于缓解国内大中城市的交通拥堵问题具有极其重要的意义,然而,轨道交通运营线路多通过城市的主要街区以及繁华商圈,车站周边地表受基坑开挖影响产生沉降等环境问题较为显著,须在支护设计阶段对其进行有效地预测及控制,以便最大程度地降低施工阶段发生工程灾害的机率。基于厦门地铁1号线车站建设过程中邻域地表沉降的监测数据,对实测沉降槽曲线进行归一化处理和统计分析,得出适用于厦门地区类似工程条件下地铁车站基坑施工诱发周边地表沉降的经验预测方法,为后续的地铁建设提供参考建议。     

高结晶度六方氮化硼的制备及表征

以硼酸和三聚氰胺为原料,在新型高温感应电炉中加热1 800 ℃进行热处理,制备六方氮化硼粉体样品,并通过扫描电镜、X射线衍射仪等设备,以及激光粒度分析、化学分析等手段对所制样品进行表征。结果表明:在设定的工艺条件下制备出结晶度高、纯度高、晶粒大的六方氮化硼。      

蚌埠市淮河南岸某高层建筑CFG桩复合地基应用探讨

以淮河南岸一级阶地某高层建筑采用CFG桩复合地基工程实例,通过利用工程地质参数复核计算、静载荷试验、沉降观测等验证资料,来探讨说明CFG桩复合地基在该区高层建筑使用的安全适用性。     

地铁车站建设结合物业开发设计初探

为了更好地将地铁车站设计与物业开发结合起来，结合国内外成功的地铁车站与物业开发相结合的实例，介绍地铁车站与物业开发结合的基本情况，总结其对城市发展的积极意义和重要作用，并根据不同的结合类型，提出几种结合设计的模式。通过对武汉地铁2号线某站与物业开发结合设计方案的分析，指出具体结合设计中需要双方设计单位协调解决的问题，提出实施建议和要求。     

PLC在刀架控制中的应用

本文介绍用可编程序控制器控制刀架，实现自动选刀．     

两课网络考试系统的设计与实现

马克思主义理论课和思想品德课是高等院校开设的必修课,课程涉及面广,教学任务重、考试工作量大。本文以两课考试为基础,对基于网络的考试活动的组织、管理、网络数据库以及系统管理进行了设计和研究。