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本较详细地描述了中国古代井盐叼下木柱工艺,并根据对自贡地区现存盐井的实地调查和有关献的考证,指出:(1)中国古代井盐叼下木柱工艺是世界钻井史上最早出现的用木制套管封隔浅层淡水和防止井壁垮塌的固井技术,起源于北宋庆历年间(1041-1048)的卓筒井套管隔水技术。(2)叼下木柱工艺在中国古代是一项非常复杂的技术,在井盐井科技史上,是一项伟大的技术创新。(3)中国古代井盐叼下木柱工艺与西方近代石油钻井中的多层结构的套管固井方法在原理上是一致的,说明两之存在着明显的传带关系。 相似文献
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一、中国古代钻井 世界钻井技术,始于水井的开凿。水井的出现,使人类摆脱了江河湖泊等天然水源的束缚而赢得了更为广阔的生存空间。中国目前已知的水井是于1974年发现于浙江省余姚县河姆渡遗址的距今6000年左右的古水井。这是一口井壁由二万多根木棍架叠而成的长方型竖井,井底距地面仅有1.35米,显然是人工挖掘而成的井。中国最早的盐井,是战国末期的公元前254~251年,由蜀郡守李冰在率领民众修筑著名的都江堰水利工程时开凿的广都盐井,井址在今四川省成都市双流县,中国井盐生产的序幕从此揭开。 相似文献
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本文从陕北盐井特征出发,结合近两年来陕北地区盐井钻井实践和米106井的工程实例,分析了盐井钻探的复杂情况及处理;针对施工当中存在的问题,介绍了过饱和盐水泥浆和对接连通的一些工艺方法。钻井实践表明,米106井的施工工艺方法保证了复杂溶腔条件下的盐井顺利施工,各项指标达到设计要求,满足甲方的生产需要,为以后的盐井对接井施工积累了丰富的经验。 相似文献
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在中国井盐生产漫长的发展和演进过程中,历代盐工以自己的艰辛劳动和开拓精神,在井盐科技史上,写下了光彩照人的篇章。凝聚着劳动人民心血和智慧的井盐科技成就与重大发明,极大地丰富了中国和世界科技史的内容。肇始于汉代的天然气煮盐,揭开了人类征服利用天然气的序幕;发明于11世纪中期的卓筒井技术,开创了人类机械钻井的先河;率先于19世纪末实现的岩盐井通腔采卤,是世界上最早完成的井间自然连通开采。在人类文明和科技 相似文献
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针对在小井眼开窗侧钻固井过程中存在的主要技术难题进行了研究,并在四川遂宁、隆昌、长宁、长山等盐井的应用中取得了成功。实践证明,该技术所制定的固井工艺方案合理,适用性强,解决了小井眼开窗侧钻技术发展面临的主要难题,提高了固井质量,降低了钻井成本,具有较好的推广价值。 相似文献
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介绍了四川光大地质钻井科技有限公司采用DST有线随钻监测系统,成功完成了在四川宜宾四丰盐化公司长2老盐井开窗侧钻水平对接长6井的施工任务。该井的成功对接,促进了常规水平对接井的发展,充分利用了停产的老盐井,节约了钻井成本,提高了采卤产量和质量,为四丰盐化公司带来了较好的经济效益和社会效益。 相似文献
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Objectives
To analyse trends in smoking prevalence in Ukraine from three surveys conducted in 2001–5, and to explore correlates of observed changes, in order to estimate the stage of tobacco epidemic in Ukraine.Design
Repeated national interview surveys in Ukraine in 2001, 2002 and 2005.Main outcome measure
Prevalence of current smoking among the population aged ⩾15 years.Results
The age‐standardised prevalence of current smoking in Ukrainian men was 54.8% in 2001 and 66.8% in 2005. Among Ukrainian women, prevalence increased from 11.5% in 2001 to 20.0% in 2005. ORs for yearly increase in prevalence were estimated as 1.164 (95% CI 1.111 to 1.220) for men and 1.187 (1.124 to 1.253) for women, which implies that, on average, 3–4% of men and 1.5–2% of women living in Ukraine join the smoking population each year.Conclusions
In Ukraine, smoking prevalence is increasing in most population groups. Among men, the medium deprivation group with secondary education has the highest smoking prevalence. Among women, while the most educated, young and those living in larger cities are the leading group for tobacco use, other groups are also increasing their tobacco use. Tobacco promotion efforts appear to have been significantly more effective in Ukraine than smoking control efforts. The decrease in real cigarette prices in Ukraine in 2001–5 could be the main factor explaining the recent growth in smoking prevalence.Ukraine is a large eastern European country with high smoking prevalence. Tobacco products are widely available at very low prices, and the transnational tobacco industry is extremely successful in promoting its products and lobbying for its interests in the legislative field. Advocacy of tobacco control has only recently achieved some success in the legislative field, with the first tobacco control law being adopted in late 2005. Ukraine ratified the Framework Convention on Tobacco Control in 2006, but there is still much cause for concern regarding the enforcement and effectiveness of the adopted legislative measures. Unfortunately, the government is not yet involved in nationwide surveillance of the tobacco problem, and the available data have mostly been gathered with funding from foreign donors. Several attempts have been made to measure the extent of the tobacco epidemic in the countries of the former Soviet Union (FSU).1,2,3,4,5,6,7 Most of these studies have shown rather high smoking prevalence among men (50–70%) and comparatively low prevalence among women (5–20%). Most countries in the FSU have similar smoking rates, while certain trends are shown to be related to the differences in how the transnational tobacco industry succeeds in every national tobacco market.6 Unfortunately, few studies have been published showing trends in smoking prevalence in the FSU.7 In Ukraine, two studies3,4 provided point estimates of smoking prevalence.The aim of this study was to analyse trends in smoking prevalence in Ukraine, on the basis of three surveys conducted in 2001–5, and to explore correlates of observed changes in order to estimate the stage of the tobacco epidemic in Ukraine. 相似文献16.
了解河南省部分食品中重金属污染的现状。方法 在河南省18个省辖市采集8大类3 657份食品样品,按照国家标准检测食品中铅、镉和汞的含量,检测结果按照GB 2762—2012《食品安全国家标准食品中污染物限量》进行评价。结果 河南省部分食品中铅含量的平均值为0.34 mg/kg,总体超标率为8.8%(320/3 656),其中粮食、肉类和蔬菜中超标率较高,分别为17.2%(95/552)、14.5%(85/587)和10.7%(57/534);部分食品中镉含量的平均值为0.054 mg/kg,总体超标率为3.9%(143/3 657),其中食用菌和蛋类中超标率较高,分别为9.6%(49/508)和8.1%(42/518);部分食品中汞含量的平均值为0.077 mg/kg,总体超标率为8.3%(303/3 657),其中蔬菜和粮食中超标率较高,分别为25.3%(135/534)和12.3%(68/551)。结论 河南省部分食品中铅、汞污染情况较为严重,其中粮食、蔬菜和肉类食品中污染情况尤为突出,需要加强监管。 相似文献
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R. B. Sashidhar Y. Ramakrishna Ramesh V. Bhat 《Journal of Stored Products Research》1992,28(4):257-260
Various traditional containers have been used in India for storage of sorghum grains. Sorghum is susceptible to fungal infestation and toxin elaboration. The present study relates to the mould and mycotoxin contamination (aflatoxin B1 and T-2 toxin) in stored sorghum in different storage containers viz. “Kotlu” (Storage rooms), earthenware pots, gunny bags and reed baskets. Aspergillus sp. and Fusarium sp. were the prominent genera and the “Kotlu” form of storage was most susceptible to fungal attack. Storage treatment had little effect on fungal contamination, but despite the fungal infestation, the mycotoxin contamination was found to be very low. 相似文献
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目的 了解山西省食源性致病菌的污染现状.方法 按照2010年度《全国食源性致病菌监测工作手册》进行.结果 1 576份样品中共检出阳性菌株149株,检出率为9.45%,其中单核细胞增生李斯特氏菌、副溶血性弧菌污染比较严重,总检出率为9.50%和8.22%,金黄色葡萄球菌、阪崎肠杆菌和沙门氏菌的总检出率分别为3.02%、1.11%和0.87%.不同类别食品中致病菌的检出率差异较大,生肉中致病菌的检出率高居榜首为49.33%,主要污染菌为沙门氏菌、单核细胞增生李斯特氏菌;沙拉中致病菌的检出率为17.39%,主要污染菌为单核细胞增生李斯特氏菌、金黄色葡萄球菌;生食水产品中致病菌的检出率为16.94%,主要污染菌为单核细胞增生李斯特氏菌、副溶血性孤菌;熟肉制品中致病菌的检出率为9.84%,主要污染菌为单核细胞增生李斯特氏菌、金黄色葡萄球菌、沙门氏菌;中式凉拌菜中致病菌的检出率为8.89%,主要污染菌为金黄色葡萄球菌;鲜榨果汁中致病菌的检出率为6.67%,主要污染菌为金黄色葡萄球菌;鲜冻水产品中致病菌的检出率为5.00%,主要污染菌为副溶血性弧菌;婴幼儿配方粉/米粉/谷粉/豆奶粉中阪崎杆菌的检出率为1.11%.结论 山西省多种食品均存在食源性致病菌不同程度的污染,应加大对散装食品、即食食品和生食水产品的监管. 相似文献