首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   125篇
  免费   1篇
电工技术   1篇
综合类   40篇
化学工业   4篇
金属工艺   8篇
机械仪表   4篇
建筑科学   4篇
轻工业   1篇
水利工程   1篇
石油天然气   3篇
无线电   6篇
一般工业技术   40篇
冶金工业   2篇
原子能技术   10篇
自动化技术   2篇
  2022年   1篇
  2021年   1篇
  2019年   2篇
  2014年   5篇
  2013年   1篇
  2012年   6篇
  2011年   14篇
  2010年   5篇
  2009年   22篇
  2008年   17篇
  2007年   17篇
  2006年   12篇
  2005年   11篇
  2004年   4篇
  2003年   1篇
  2002年   2篇
  2001年   2篇
  1999年   1篇
  1996年   1篇
  1984年   1篇
排序方式: 共有126条查询结果,搜索用时 15 毫秒
1.
茨21-133井CO2吞吐技术初步试验   总被引:1,自引:0,他引:1  
刘涛 《特种油气藏》2003,10(3):82-83,90
茨榆坨油田茨13块原油属于普通稠油,1993年开始蒸汽吞吐采油,从第二轮开始效果明显变差,注汽返排率低,有效周期短,产量下降快,套管变形井增多。针对这些问题,在该区块茨21—133井进行CO2吞吐采油工艺现场试验,获得成功,增油效果明显。  相似文献   
2.
基于Virtool软件的虚拟现实技术应用在谢公祠的保护和研究中,可以实现虚拟体验、时空转换、构件分析等交互功能.本文介绍了实现这些功能的软件处理方法以及效果,展望了该软件用于建筑保护工作和科学普及的应用前景.  相似文献   
3.
茨9区油藏为发育边水的中孔中高渗油藏,利用直井开发的弊端日益凸现,水平井开发可行性研究的论证认为,该区油藏部署水平井开发优势明显。在剩余油分布规律的基础上利用数值模拟的方法对茨9区进行水平井开发方案设计,确定了水平井开发的目的层位、水平井段方向以及长度,并利用数值模拟对开发方案进行结果预测,结果表明水平井开发从累积产油量以及含水上升情况等方面都远优于直井开发,综上为茨9区的进一步开发提出新的方向。  相似文献   
4.
自1860年至1900年,圆明园两次遭受入侵外敌的毁坏。历尽劫难的圆明园,在民国时期,成了民国词人文学创作的表现题材。民国词人将自己游览圆明园时的所见所闻、所思、所感,运用多种艺术手法加以表现。这些呈现在民国词中的圆明园镜像,体现了民国词人对历史与社会变迁的关注,丰富了词的情感内涵,具有重要的词史意义。  相似文献   
5.
Since monochromated transmission electron microscopes have become available, the determination of bandgaps and optical properties using electron energy loss spectrometry (EELS) has again attracted interest. The underlying idea is very simple: below the bandgap energy no transitions can contribute to the valence EELS signal. However, the bandgap cannot be directly read out from the recorded data. Therefore the optical properties cannot be determined correctly from the low loss using the Kramers-Kronig relations. We will discuss under which conditions relativistic effects may be suppressed. It is demonstrated that scanning TEM (STEM) geometry is not applicable for most bandgap measurements.  相似文献   
6.
词以抒情为主,拙于叙事。然而,在唐宋词中有很多叙事性作品,特别是以联章体形式出现的较多。从这个意义上讲,词能叙事并具有叙事性。但是,学术界对词的叙事性较少关注。文章列举和分析了唐宋词中以联章体形式出现的叙事性作品,并对叙事性作品按题材内容进行分类,最后指出诗歌叙事性艺术渊源及有关影响。  相似文献   
7.
Bismuth iron garnet (Bi3Fe5O12, BIG) epitaxial thin films were grown on single crystal (Gd3Ga5O12, GGG) (111) and (001) substrates by rf-magnetron sputtering technique. Processing parameters have been optimized to obtain high deposition rate (2.74 μm/h) and the surface rms roughness less than 10 nm. X-ray diffraction reveals films epitaxial quality: exclusive (111) or (001) orientation with narrow rocking curves and strong in-plane texture. Films possess low optical loss and magneto-optical Faraday rotation (FR) as high as 5 deg/μm at 677 nm wavelength. Comparative analysis of films grown on (111) and (001) substrates clearly shows significant superiority of BIG/GGG(001) film. For this film, the coercive field ∼100 Oe appears to be 2.5 times lower while the optical transmission to be 10% higher than that for BIG/GGG(111) film. Enhanced magneto-optical performance of BIG/GGG(001) films relies upon better accommodation of the film-to-substrate mismatch strain through the tetragonal BIG lattice distortions compared to the rhombohedral one in BIG/GGG(111) films.  相似文献   
8.
Thin films of Bi2Se3, Bi2Se2.9Te0.1, Bi2Se2.7Te0.3 and Bi2Se2.6Te0.4 are prepared by compound evaporation. Micro structural, optical and electrical measurements are carried out on these films. X-ray diffraction pattern indicates that the as-prepared films are polycrystalline in nature with exact matching of standard pattern. The composition and morphology are determined using energy dispersive X-ray analysis and scanning electron microscopy (SEM). The optical band gap, which is direct allowed, is 0.67 eV for Bi2Se3 thin films and the activation energy is 53 meV. Tellurium doped thin films also show strong optical absorption corresponding to a band gap of 0.70-0.78 eV. Absolute value of electrical conductivity in the case of tellurium doped thin film shows a decreasing trend with respect to parent structure.  相似文献   
9.
The biogenicity of ancient morphological microfossil-like objects can be established by linking morphological (e.g. cell remnants and extracellular polymeric matrix) and chemical (e.g. isotopes, biomarkers and biominerals) evidence indicative of microorganisms or microbial activity. We have developed a non-destructive micro-analytical ion beam system capable of measuring with high spatial resolution the stable carbon isotope ratios of thin samples used for transmission electron microscopy. The technique is based on elastic scattering of alpha particles with an energy of 2.751 MeV. At this energy the 13C cross section is enhanced relative to the pure Rutherford cross section for 13C, whereas the 12C cross section is reduced relative to its pure Rutherford cross section. Here we report the initial results of this experimental approach used to characterize ultramicrotomed sections of sulfur-embedded graphite and microbial cells.  相似文献   
10.
A laser interferometer gravitational wave detector requires an ultra high vacuum in the tubes in which the laser beams pass. To avoid noise due to scattered light from the surface of tubes, the surface should be treated with “black” coating without increasing the outgassing rate. We found that diamond-like Carbon (DLC) coatings are suitable for this aim. An outgassing rate of at was achieved for DLC coatings on SUS304 without baking. This rate was better than the surface of SUS316 with baking. The reflectivity of the DLC surface was 5% at minimum for a laser beam of Nd:YAG () which is used as a light source for the gravitational wave detector.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号