深孔纳米复合水泥基护壁堵漏材料研究          下载免费PDF全文

王胜  吴丽钰  蒋贵  张统得  陈礼仪 《探矿工程》2021,48(12):7-13

本文围绕深部钻探技术中护壁堵漏材料性能的实际需要,研制了一种深孔纳米复合水泥基护壁堵漏新材料。首先,通过分析100 ℃条件下2种水泥材料的基本性能,确定了G级油井水泥为胶凝材料;然后,基于深孔钻探护壁堵漏材料的性能缺陷,采用特种纤维、纳米材料针对性改善水泥基浆液的力学性能,并优选早强剂（ZQ）、减水剂（GB）作为外加剂进行正交实验,进而研制出纳米复合水泥基护壁堵漏材料优化配方;最后,对其主要性能进行分析评价。结果表明该材料在深孔钻探中浆液流动性好,力学性能优异,综合性能满足深孔钻探护壁堵漏需求。  相似文献   

Stable ⁸⁵Rb micro vapour cells: fabrication based on anodic bonding and application in chip-scale atomic clocks     

苏娟  邓科  郭等柱  汪中  陈兢  张耿民  陈徐宗 《海洋学报(英文版)》2010,29(11)

We describe the microfabrication of ⁸⁵Rb vapour cells using a glass-silicon anodic bonding technique and in situ chemical reaction between rubidium chloride and barium azide to produce Rb. Under controlled conditions, the pure metallic Rb drops and buffer gases were obtained in the cells with a few mm³ internal volumes during the cell sealing process. At an ambient temperature of 90 ℃ the optical absorption resonance of ⁸⁵Rb D1 transition with proper broadening and the corresponding coherent population trapping (CPT) resonance, with a signal contrast of 1.5% and linewidth of about 1.7 kHz, have been detected. The sealing quality and the stability of the cells have also been demonstrated experimentally by using the helium leaking detection and the after-9-month optoelectronics measurement which shows a similar CPT signal as its original status. In addition, the physics package of chip-scale atomic clock (CSAC) based on the cell was realized. The measured frequency stability of the physics package can reach to 2.1×10^-10 at one second when the cell was heated to 100 ℃ which proved that the cell has the quality to be used in portable and battery-operated devices.  相似文献   

中国沿海管角螺4个自然群体形态差异的比较   总被引：3，自引：0，他引：3  

罗福广  李斌  罗平秀  郑惠芳  潘英 《中国海洋大学学报(自然科学版)》2010,40(3)

运用多变量形态度量学方法,采用7个形态性状对中国北海、温州、湛江、连云港4个管角螺自然群体的形态变异进行分析研究.聚类分析和主成分分析结果表明,北海群体与湛江群体形态最为接近,而温州群体与连云港群体形态差异较大.主成分分析构建了4个主成分,其贡献率:主成分1为42.74%,主成分2为18.23%,主成分3为15.83%,主成分4为11.83%,累计贡献率为88.63%.建立了4个管角螺群体的判别函数,其判别准确率P_1为81.3%～95.6%,判别准确率P_2为75.0%～93.3%,综合判别率为87.3%.3种多元分析结果均认为,4个群体在形态上有一定程度的差异,与地理分布、环境、气候、生物饵料等因子有关,但差异尚未达到亚种水平.  相似文献   

AN~2 APPLICATION IN THE METRODS OF POPULATION GEOGRAPHY     

Zhang Shulin 《地理学报(英文版)》1995,(1)

1.PoPulation~aphyisthestudy0fthespatialdistributionmdarrangnatsofhumanpoPulation.ItisthesdenceofhowspatialvariarionsinthecomPosihon,growth,whgraion,anddistribLItionofpoPulatonsaiere1ataltospatialvariationsinthenatureofplaces.ThemethodsplayanimPohanroleinr…  相似文献   

中国塔吉克族人口发展初探     

吐尔.  马 《干旱区地理》1995,18(3):72-78

本文根据全国历来四次人口普查资料，对我国塔吉克族人口形热进行了简要的论述。文中阐述了塔吉克族人口规模的发展、变化以及人口再生产类型，并简述了相关的社会、经济、文化等方面的问题。  相似文献   

四川绵阳官司河流域防护林的演替预测     

阳小成  李旭光  叶志义 《山地学报》1995,(4)

选取６个样地，以“空间代替时间”法研究了官司河流域的松柏栎混交防护林的优势种群动态。结果显示：各种群在群落次生演替过程中普遍更新欠佳，林木大小级结构呈不稳定或衰退状态，据非线性演替理论，并结合防护林现状，预测防护林的可能演替趋势为：今后人为干扰若能保持较长期相对稳定，则针阔叶混交的群落类型亦将保持基本稳定；但随土壤类型的不同，而渐分化成松栋混交林和柏栎混交林．  相似文献   

川西地区劳动就业研究   总被引：3，自引：0，他引：3  

陈国阶 《地理研究》1993,12(3):89-99

以川西作为研究区域,对农村劳动力转移或非农就业从自然—人文相结合的观点进行了探讨。  相似文献   

辽东山区人口地域分布研究     

高明辛 《山地学报》1993,(3)

本文在分析了辽东山区土地资源特征和人口特征的基础上,从三个角度讨论了辽东山区的人口垂直分布特征,同时还详细分析了人口布局不合理对山区生态环境和经济的影响。并指出,适度移民、并村并点、整合山村及建设农村小集镇是调整山区人口布局,促进山区经济发展和生态环境恢复的有效途径。  相似文献   

Structural Spatial Interaction*     

James Pooler 《The Professional geographer》1993,45(3):297-305

This paper identifies a concept of structural spatial interaction. Although it is defined differently from its counterpart of structural unemployment in economics, it attempts to define a similar idea. In economics, the focus is on equilibrium in the supply and demand of labor. In this paper structural interaction is that which minimizes aggregate distance travelled, subject to constraints on origins and destinations. The structural interaction model produces an equilibrium, therefore, in the supply and demand of movers, while identifying a spatially efficient trip distribution. It is portrayed as a type of relaxed interaction model and is illustrated using an example of structural migration with Canadian interprovincial migration data.  相似文献   

POPULATION DYNAMICS AND PRODUCTION OF NEANTHES JAPONIC A (IZUKA)IN A SHRIMP POND   总被引：1，自引：0，他引：1  

丘建文  吴宝铃 《中国海洋湖沼学报》1993,11(4):360-367

During late February to mid-March, 1991, when mature N. japonica swarmed in the sea surface off Jimo County, Qingdao, seawater containing numerous early embryos was pumped into a nearby 2.7 ha. muddy-sand shrimp pond, where the embryos continued to develop. 800000 Penaeus chinensis seedlings were introduced into the pond on May 30, 1991. Monthly benthic samplings were carried out to determine the population dynamics and production of N. japonica in this atypical environ -ment.The density of N. japonica varied from 0 to 20400 ind./m2. The predation of P. chinensis was considered to be responsible for the mass mortality of N. japonica in June through July, when the worms were 2.2-3.3cm in length and lived in the top 2-4cm sediment. From August to September of 1991, the hottest period in the site, there was no substantial mortality of N. japonica as reported in earlier literature. This was explained by the deeper burrowing of the' worms that protected them from predation by shrimps.Monthly biomass ranged f  相似文献