全文获取类型
收费全文 | 195篇 |
免费 | 9篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 1篇 |
综合类 | 1篇 |
化学工业 | 71篇 |
金属工艺 | 5篇 |
机械仪表 | 4篇 |
建筑科学 | 4篇 |
能源动力 | 9篇 |
轻工业 | 18篇 |
水利工程 | 2篇 |
无线电 | 4篇 |
一般工业技术 | 55篇 |
冶金工业 | 6篇 |
原子能技术 | 2篇 |
自动化技术 | 23篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 4篇 |
2021年 | 14篇 |
2020年 | 9篇 |
2019年 | 12篇 |
2018年 | 10篇 |
2017年 | 16篇 |
2016年 | 8篇 |
2015年 | 5篇 |
2014年 | 8篇 |
2013年 | 18篇 |
2012年 | 16篇 |
2011年 | 24篇 |
2010年 | 14篇 |
2009年 | 7篇 |
2008年 | 5篇 |
2007年 | 5篇 |
2006年 | 4篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有205条查询结果,搜索用时 15 毫秒
11.
Janice Paslawski Mehdi Nemati Gordon Hill John Headley 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(7):992-1000
BACKGROUND: Naphthenic acids are carboxylic acid compounds of oil sands wastewaters that contribute to aquatic toxicity. Biodegradation kinetics of an individual naphthenic acid compound in two types of continuous‐flow bioreactors were investigated as a means of improving remediation strategies for these compounds. RESULTS: This study evaluates the kinetics of biodegradation of trans‐4‐methy‐1‐cyclohexane carboxylic acid (trans‐4MCHCA) using two bioreactor systems and a microbial culture developed in previous work. Using a feed concentration of 500 mg L?1 the biodegradation rate of trans‐4MCHCA in the immobilized cell bioreactor was almost two orders of magnitude higher than that in a continuously stirred tank bioreactor. The maximum reaction rates of 230 mg (L d)?1 at a residence time of 1.6 d (40 h) and 22 000 mg (L d)?1 at a residence time of 2.6 h were observed in the continuously stirred tank and immobilized cell bioreactors, respectively. In a second immobilized cell system operating with a feed concentration of 250 mg L?1, a comparable maximum reaction rate (21 800 mg (L d)?1) was achieved at a residence time of 1.0 h. CONCLUSION: The use of immobilized cell bioreactors can enhance the biodegradation rate of naphthenic acid compounds by two orders of magnitude. Further, biodegradation greatly reduces the toxicity of the effluent wastewater. Copyright © 2009 Society of Chemical Industry 相似文献
12.
Influence of two nano-size additives on electrical properties of suspension matrix of self-flowing low-cement high alumina refractory castable is investigated. For this purpose, castament FS 10 and FS 20 on the basis of polycarboxylate ether were considered. The self-flow value, workability and mechanical strength of the castable are evaluated and their relations with electrical conductivity are determined. Using these relations, the type and optimum amount of proper additive for these refractory castables are determined. It was shown that if the electrical conductivity of matrix suspension is less than 0.71 mS/cm, high alumina low-cement self-flowing refractory castable can be obtained. The best self-flow, sufficient working time and adequate mechanical strength in the castables are obtained with 0.08 wt.% FS 20. 相似文献
13.
In this research, a modified, cost effective sol-gel procedure applied to synthesize BaTiO3 nanoparticles. XRD and electron microscopy (SEM and TEM) applied for microstructural characterization of powders. The obtained results showed that the type of precursors, their ratio and the hydrolysis conditions had a great effect on time, temperature and therefore the costs of the synthesis process. By selection, utilization of optimized precursor's type, hydrolysis conditions, fine cubic BaTiO3 nanoparticles were synthesized at low temperature and in short time span (1 h calcination at 800 °C). The proposed procedure seems to be more preferable for mass production.The result indicated that the polymorphic transformation to tetragonal (ferroelectric characteristic) occurred at 900 °C, which might be an indication of being nanosized. 相似文献
14.
Ashok Kumar Singh N. Chaurasia Shahla Rahmani Jaya Srivastava Bharat Singh 《Catalysis Letters》2004,94(3-4):135-141
The NO/H2 reaction has been studied over a Ni loaded carbon film catalysts using in situ FTIR spectroscopy at the temperature range 25–350°C. On these catalysts, the differences in activity and selectivity were found depending on the nature of the surface functional groups. These differences were correlated with transient infrared spectral features which appeared during the reaction. It has been proved experimentally that the chemical character of the support is of vital importance during the process. The rise in NO conversion and N2 selectivity was observed when the surface of the catalysts was changed by the NH3 chemisorption. Amide and/or imide species formed due to the reduction of ammonium salts of carboxylic acids can play a significant role as active centers during the NO reduction. 相似文献
15.
This paper reports the results from investigating the feasibility of calculating flame temperature from a natural gas-fired furnace based on blackbody radiation in the visible spectral range. If successful, the visible spectral range would provide data for multi-task applications such as emission line analysis and temperature calculation simultaneously. A probe containing a lens connected to the fiber-optic cables is inserted into the furnace and pointed towards the flame. Spectral intensity data are fed back to a spectrometer and then to a monitoring computer. The approach is first applied to various furnace types using the visible range to establish a baseline for the technique. The results for temperature calculations in the visible range are then compared with those taken in the near-IR (NIR) range under the same conditions. This comparison indicates that temperatures calculated from visible region could be as accurate as the one obtained from NIR region. Challenges associated with this technique are also discussed. 相似文献
16.
Ryan Riess Mehdi Nemati John Headley Gordon Hill 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2005,80(6):662-668
One of the main challenges in the treatment of polycyclic aromatic hydrocarbons (PAHs) in controlled bioreactors is the hydrophobicity and low solubility of these compounds in the aqueous phase, resulting in appreciable mass transfer limitations within the bioreactor. To address this challenge, we have developed a modified roller bioreactor (Bead Mill Bioreactor) in which inert particles are used to improve mass transfer from the solid phase to the aqueous phase. Experimental results with naphthalene as a model PAH and Pseudomonas putida as a candidate bacterium indicate that both the mass transfer rate from the solid phase to liquid phase and the biodegradation rate in the Bead Mill Bioreactor (BMB) were significantly higher than those in a conventional roller bioreactor (20‐fold and 5.5‐fold, respectively). The enhancement of mass transfer was dependent on the type, size and volumetric loading of the inert particles, as well as concentration of particulate naphthalene. The highest mass transfer coefficient (kLa = 2.1 h?1) was achieved with 3 mm glass beads at a volumetric loading of 50% (particle volume/working volume) with 10 000 mg dm?3 particulate naphthalene. The maximum biodegradation rate of naphthalene attained in the bead mill bioreactor (59.2 mg dm?3 h?1 based on the working volume and 118.4 mg dm?3 h?1 based on the liquid volume) surpasses most other rates published in the literature and is equivalent to values reported for more complex bioreaction systems. The bead mill bioreactor developed in the present work not only enjoys a simple design but shows excellent performance for treatment of PAHs suspended in an aqueous phase. This fundamental information will be of significant value for future studies involving soil‐bound PAHs. Copyright © 2005 Society of Chemical Industry 相似文献
17.
Ramezan Nemati Keshteli Reza Baradaran Kazemzadeh Amirhossein Amiri Rassoul Noorossana 《Quality and Reliability Engineering International》2014,30(5):633-644
Profile is a relation between one response variable and one or more explanatory variables that represent quality of a product or performance of a process. On the other hand, process capability indices are measures to help practitioners in improving the processes to satisfy the customer's expectations. Few researches are done to account for the process capability index in the areas of profile monitoring. All of these researches are focused on process capability index in simple linear profile. In all of these methods, response variables in different levels of explanatory variable are considered, and the relationship in all range of explanatory variable is neglected. In this paper, a functional method is proposed to measure process capability index of circular profiles in all range of explanatory variable. The proposed method follows the traditional definition of process capability indices. The functional method uses reference profile, functional specification limits and functional natural tolerance limits to present a functional form of process capability indices. This functional form results in measuring the process capability in each level of explanatory variable in circular profile as well as a unique value of process capability index for circular profile. The application of the proposed method is illustrated through a real case in automotive industry. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
18.
Seyyed Ali Shojaee Mohammad Maleki Shahraki Mohammad Ali Faghihi Sani Ali Nemati Abbas Yousefi 《Journal of Materials Science: Materials in Electronics》2010,21(6):571-577
This paper describes a solution-based technique for fabrication of varistor grade composite nanopowders. The method consists
of coating major varistor dopants on the surface of the ZnO nanoparticles. As a result, a homogenous mixture of dopants and
ZnO nanoparticles will be achieved. TEM results indicated that a composite layer of dopants with the average particle size
of 9 nm on the surface of ZnO nanoparticles has been successfully prepared. Sintering of the coated powders was performed
in temperatures as low as 850 °C and final specimens with average particle size of 900 nm and density of 98.5% were achieved.
In comparison to conventional mixing, varistors prepared from coated nanopowders exhibited superior electrical properties
and microstructure homogeneity. The improvement of electrical properties can be attributed to small grain size, homogenous
distribution of dopants and elimination of large Bi-Pockets. In addition, the processing route of schottky barrier formation
is quite different from what is generally considered as the method of barrier formation in ZnO grain boundaries. 相似文献
19.
Shahrzad Hosseini Vajargah Hamid Reza Madaah Hosseini Ziarat Ali Nemati 《International Journal of Applied Ceramic Technology》2008,5(5):464-468
Nanocrystalline Y3− x MM x Fe5 O12 powders (MM denotes Misch-metal, x =0.0, 0.25, 0.5, 0.75, and 1.0) were synthesized by a sol–gel combustion method. Magnetic properties and crystalline structures were investigated using X-ray diffraction (XRD), a vibrating sample magnetometer (VSM), and a scanning electron microscope. The XRD patterns showed that the single-phase garnet of Y3− x MM x Fe5 O12 was formed at x values ≤1.0. The saturation magnetization of powders increased with decreasing MM content and reached the maximum value at Y3 Fe5 O12 . The crystallite size of powders calcined at 800°C for 3 h was in the range of 38–53 nm. 相似文献
20.
Nils‐Jrgen Knudsen Dal Agnese Kocere Jens Wohlmann Simon Van Herck Tobias A. Bauer Julien Resseguier Shahla Bagherifam Hilde Hyldmo Matthias Barz Bruno G. De Geest Federico Fenaroli 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(5)
The zebrafish embryo is a vertebrate well suited for visualizing nanoparticles at high resolution in live animals. Its optical transparency and genetic versatility allow noninvasive, real‐time observations of vascular flow of nanoparticles and their interactions with cells throughout the body. As a consequence, this system enables the acquisition of quantitative data that are difficult to obtain in rodents. Until now, a few studies using the zebrafish model have only described semiquantitative results on key nanoparticle parameters. Here, a MACRO dedicated to automated quantitative methods is described for analyzing important parameters of nanoparticle behavior, such as circulation time and interactions with key target cells, macrophages, and endothelial cells. Direct comparison of four nanoparticle (NP) formulations in zebrafish embryos and mice reveals that data obtained in zebrafish can be used to predict NPs' behavior in the mouse model. NPs having long or short blood circulation in rodents behave similarly in the zebrafish embryo, with low circulation times being a consequence of NP uptake into macrophages or endothelial cells. It is proposed that the zebrafish embryo has the potential to become an important intermediate screening system for nanoparticle research to bridge the gap between cell culture studies and preclinical rodent models such as the mouse. 相似文献