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   71篇
  免费   6篇
化学工业   14篇
建筑科学   2篇
能源动力   32篇
轻工业   5篇
水利工程   1篇
无线电   3篇
一般工业技术   7篇
冶金工业   8篇
原子能技术   1篇
自动化技术   4篇
  2021年   8篇
  2020年   1篇
  2019年   3篇
  2018年   4篇
  2017年   10篇
  2016年   6篇
  2013年   7篇
  2012年   5篇
  2011年   6篇
  2010年   8篇
  2009年   2篇
  2008年   4篇
  2007年   1篇
  2006年   3篇
  2003年   2篇
  1998年   2篇
  1997年   1篇
  1992年   1篇
  1990年   1篇
  1989年   1篇
  1981年   1篇
排序方式: 共有77条查询结果,搜索用时 31 毫秒
1.
2.
We developed a module for surgical team training using briefings in simulated crisis scenarios and here we report preliminary findings. Nine surgical teams (34 trainees) participated in a pre-training simulation, followed by an interactive workshop on briefing and checklists, and then a post-training simulation. Both technical and non-technical skills were assessed via observation during simulations by expert trainers who provided feedback on performances at the end of simulation. Trainees also reported their attitudes to briefings and evaluated the training. Pre-training attitudes to briefing were positive, some of which improved post-training and trainees’ evaluation of the training was positive. Surgeons’ technical skill improved significantly post-training, but their decision-making skill was rated lower than other non-technical skills, compared to other trainees. The training did not appear to greatly improve non-technical skill performance. Training surgical teams in simulation is feasible but much more work is needed on measurement development and training strategy to confirm its efficacy and utility.  相似文献   
3.
In this study, the effect of potassium hydroxide concentration in anodization bath, anodization time, and calcination temperature on the photo-electrochemical behavior of metallic titanium/mixed phase titanium oxide is investigated. Further, the phase structure of a titanium oxide photocatalyst prepared on a titanium electrode through a high-voltage anodization method is examined. The study exploits photo-electrochemical, Fourier transform infrared spectroscopy attenuated total reflectance (FTIR–ATR), X-ray diffraction, and Raman spectroscopic methods to obtain better insights into the mechanism of mixed-phase titanium oxide formation. In this regard, the photo-electrochemical properties of the photocatalysts prepared in single excitation energy, violet light (410 nm), were investigated. The anodization time and the potassium hydroxide concentration in the anodization bath have significant effects on the photo-electrochemical properties of the photocatalysts. The experiments show that the effect of potassium hydroxide concentration is a function of the anodization potential applied, demonstrating different patterns as the anodization potential changes. Furthermore, FTIR-ATR, X-ray diffraction, and Raman spectroscopic studies reveal that the extended anodization times decrease the population of OH-containing groups, leading to lower photo-electrochemical performance. On the other hand, the formation of anatase phases becomes more favorable only in the extended anodization times before application of the calcination process. Additionally, the calcination temperature has a significant impact on the anatase to rutile ratio. Finally, increasing potassium hydroxide concentration leads to the formation of an amorphous titanium oxide layer. It can be concluded that the obtained information might have a significant impact on the preparation of titanium oxide and other metal oxide photocatalysts through the high voltage anodization process.  相似文献   
4.
Removal of melanoidin pigment from molasses spent wash was investigated using a new adsorbent. Solid adsorbents were fabricated from charcoal fly ash and clay. The effect of various molasses concentration (6 to 12 g/l) on removal efficiency was studied. The obtained results revealed that maximum removal efficiency of 82% was achieved at the molasses concentration of 6 g/l and contact time of 7 h. The saturated porous adsorbents were regenerated and reused to conduct similar experiments. The achieved data showed that more than 90% of the capacity of the fresh adsorbent was recovered after regeneration. Various adsorption isotherms of Langmuir, Freundlich, Temkin and Harkins-Jura were applied to interpret the obtained experimental data. The obtained results revealed that the sorption data were well described by the Harkins-Jura model. Also, various kinetic models of pseudo-first order, pseudo-second order, Elovich and intra-particle diffusion were used to predict the characteristic parameters which are useful in process design. It was concluded that the best fit was obtained with pseudo-second order kinetic model at low molasses concentrations.  相似文献   
5.
6.
This study aimed to assess performance in simulated minimal access surgery (MAS) tasks under a range of viewing conditions. MAS conventionally uses 2d viewing systems which produce a flat image. However, 3d viewing systems which produce stereoscopic depth information should in principle lead to better depth perception, and improve performance on tasks which require appropriate spatial representation of layout and depth. The study compared a novel 3d viewing system with a state of the art 2d viewing system and a direct viewing condition ('open surgery') as a point of reference. Tasks included pulling and cutting of threads using standard surgical instruments. Medical students (n = 16) were allocated to viewing conditions according to a Latin square and carried out 120 tasks each. Assessment was by means of a 3d movement tracking device providing a number of performance parameters (time on task, velocity, number of movements, distance travelled). In addition instrument movement was video-recorded and analysed by four observers to validate the tracking device. Results from tracking data and observer data were highly correlated (r > 0.85). While open surgery naturally scored highest, the key finding was the clearly superior performance in the 3d condition compared to 2d. Thus modern 3d viewing systems can improve performance in a realistic task.  相似文献   
7.
Nano‐alumina powders containing yttrium oxide were synthesized via the sol‐gel method using aluminum chloride hexahydrate as catalyst precursor. Fourier transform infrared analysis showed the presence of Al‐O and Al‐O‐Al bands in the powder structure and X‐ray diffraction spectra proved that the alumina was in the amorphous phase. The amorphous nano‐alumina powders were shown to be mesoporous with a high surface area, and both spherical and slit‐shaped particles were found in the calcined powder. A high percentage of conversion of oil to biodiesel was obtained in the transesterification reaction and the synthesized nano‐alumina powders could be easily regenerated for further use. The amorphous nano‐alumina powder can thus be recommended for use as active catalyst in the transesterification reaction for biodiesel production on the industrial scale.  相似文献   
8.
This study deals with production of lipase in solid state fermentation by Rhizopus oryzae from sugarcane bagasse. A tray bioreactor was designed for the extracellular enzyme production. Daily, lipase production was evaluated at several incubation temperatures. Furthermore, the influence of temperature and humidity of the cabinet, depth of solid bed, particle size, initial moisture content and supplementary substrate (olive oil) as carbon source was investigated. The obtained results showed that bioreactor temperature of 45 °C, humidity of 80%, solid bed depth of 0.5 cm, particle size in the range of 0.335–1 mm, substrate initial moisture content of 80% for the top tray and 70% for the middle tray and supplementary substrate of 8% (v/w) olive oil led to maximum lipase production. Under optimum fermentation conditions after 72‐h incubation, maximum lipase activities for the top, middle and bottom trays were 215.16, 199.36 and 52.64 U gds?1, respectively.  相似文献   
9.
A new and simple method was developed to produce gelatin nanoparticles of ~ 30–40 nm for use as carriers for drug release applications. The nanoparticles were uniform in size and well dispersed. An anticancer drug, 5‐fluorouracil, was encapsulated with an efficiency as high as 85%. The nanoparticles showed sustained release of 5‐fluorouracil, and release rates varied with amount of crosslinking in the nanoparticles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.  相似文献   
10.
Chlorinated hydrocarbons and aromatics constitute the major class of volatile organic compounds that contaminate groundwater. In this study, the equilibrium uptake and column dynamics for the adsorption of dichloromethane (as a typical chlorinated hydrocarbon) and toluene (as a representative of aromatic compounds) from aqueous phase on coal-based granular activated carbon (GAC) were investigated. The adsorption isotherms were measured in a temperature range of 20–40°C. The experimental data obtained were correlated with several adsorption isotherm models. The Langmuir model was well adapted to describe the dichloromethane adsorption on GAC, while the adsorption of toluene on GAC was found to be well described by the Langmuir-BET hybrid model in the stated temperature range with R-squared value of about 0.99. The variations in adsorption breakthrough curves of toluene and dichloromethane with respect to operational parameters such as initial concentration, flow rate, column length, and temperature were investigated. The experimental breakthrough curves of both adsorbates are well fitted by Yan's model with high accuracy (R-squared value of 0.98–99) in most cases.  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