全文获取类型
收费全文 | 179篇 |
免费 | 8篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 48篇 |
金属工艺 | 40篇 |
机械仪表 | 5篇 |
建筑科学 | 2篇 |
能源动力 | 6篇 |
轻工业 | 2篇 |
无线电 | 16篇 |
一般工业技术 | 22篇 |
冶金工业 | 8篇 |
自动化技术 | 35篇 |
出版年
2023年 | 1篇 |
2022年 | 14篇 |
2021年 | 7篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 1篇 |
2017年 | 8篇 |
2016年 | 4篇 |
2015年 | 7篇 |
2014年 | 17篇 |
2013年 | 17篇 |
2012年 | 13篇 |
2011年 | 16篇 |
2010年 | 7篇 |
2009年 | 12篇 |
2008年 | 16篇 |
2007年 | 6篇 |
2006年 | 10篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 6篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1996年 | 1篇 |
1987年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有187条查询结果,搜索用时 15 毫秒
11.
Claudia Mihaela Ninciuleanu Raluca Ianchi Elvira Alexandrescu Ctlin Ionu Mihescu Sabina Burlacu Bogdan Tric Cristina Lavinia Nistor Silviu Preda Cristina Scomoroscenco Ctlina Gîfu Cristian Petcu Mircea Teodorescu 《International journal of molecular sciences》2022,23(18)
The present work aims to show how the main properties of poly(methacrylic acid) (PMAA) hydrogels can be engineered by means of several silicon-based fillers (Laponite XLS/XLG, montmorillonite (Mt), pyrogenic silica (PS)) employed at 10 wt% concentration based on MAA. Various techniques (FT-IR, XRD, TGA, SEM, TEM, DLS, rheological measurements, UV-VIS) were used to comparatively study the effect of these fillers, in correlation with their characteristics, upon the structure and swelling, viscoelastic, and water decontamination properties of (nano)composite hydrogels. The experiments demonstrated that the nanocomposite hydrogel morphology was dictated by the way the filler particles dispersed in water. The equilibrium swelling degree (SDe) depended on both the pH of the environment and the filler nature. At pH 1.2, a slight crosslinking effect of the fillers was evidenced, increasing in the order Mt < Laponite < PS. At pH > pKaMAA (pH 5.4; 7.4; 9.5), the Laponite/Mt-containing hydrogels displayed a higher SDe as compared to the neat one, while at pH 7.4/9.5 the PS-filled hydrogels surprisingly displayed the highest SDe. Rheological measurements on as-prepared hydrogels showed that the filler addition improved the mechanical properties. After equilibrium swelling at pH 5.4, G’ and G” depended on the filler, the Laponite-reinforced hydrogels proving to be the strongest. The (nano)composite hydrogels synthesized displayed filler-dependent absorption properties of two cationic dyes used as model water pollutants, Laponite XLS-reinforced hydrogel demonstrating both the highest absorption rate and absorption capacity. Besides wastewater purification, the (nano)composite hydrogels described here may also find applications in the pharmaceutical field as devices for the controlled release of drugs. 相似文献
12.
We deposited BiFeO3 films on stainless steel substrates using a simple low-temperature wet-chemical route. Bismuth and iron nitrates were used as metal source and citric acid as chelating agent to prepare a water solution and deposit the film by dipping the steel substrate in the viscous solution. We have investigated the composition, crystallinity and structure of the BiFeO3 film on steel by X-ray diffraction, X-ray photoelectron spectroscopy, high resolution scanning electron microscopy, conventional and high resolution transmission electron microscopy, and energy dispersive spectroscopy techniques. The film deposited on the steel substrate has two sublayers: a very thin (about 100 nm) nanocrystalline layer, with crystallite size of few nanometers, and a thicker (below 1 μm) crystalline layer. 相似文献
13.
In this work, we report the fabrication of sensors’ element for humidity or gases, prepared by in situ polymerization of aniline N-propansulfonic acid using ammonium persulfate in acidic medium. The polymer is being used in the form of powder or deposited in multiple layers onto the PET film. Various techniques including Fourier Transform infrared (FTIR), ultraviolet-–visible spectroscopy (UV–vis), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to characterize the as-prepared sensing materials. The film has been tested for humidity influence, where the significant variations in electrical characteristics were observed, suggesting its usefulness for humidity sensors. Also, for different organic and inorganic gases, a relatively low operating temperature and important sensitivity were observed that indicate its applicability as an active element for general gases sensors. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47743. 相似文献
14.
Iulian Riposan Mihai Chisamera Stelian Stan Pavel Toboc Geir Grasmo Douglas White Chris Ecob Cathrine Hartung 《Journal of Materials Engineering and Performance》2011,20(1):57-64
Two main chemistry systems of micro-inclusions can be identified in ductile iron: Ca-S-X and Mg-Si-O-X with the majority of
the inclusions regardless of treatment type and location being of the second type, silicates. Laboratory investigations have
shown that simple silicates were present in the matrix, while more complex silicates were present in conjunction with graphite,
probably acting as graphite nucleation sites. In these more complex silicates, elevated levels of Al, Ca, Ce and La were typical.
Comparing micro-particles embedded in iron matrix and graphite nodules of iron treated with pure Mg-metal and iron treated
with MgFeSi alloy showed a higher amount of complex silicates with elevated Al-levels in the iron treated with MgFeSi. Further
laboratory investigation was undertaken to explore which source of Al and which range of residual Al would have a favorable
impact on the graphite nucleation in ductile iron. The work showed that a residual aluminum of 0.005 to 0.020 wt.% appears
to be beneficial for improving ductile iron solidification characteristics without the incidence of pinholes. Greatest benefits
were achieved when introducing the Al into the iron via an inoculant late during processing or via a pre-conditioner to the
base iron. Al added via the MgFeSi provided less benefit. Some case studies illustrating the effect of Al in ductile iron
are also presented, as Al-containing pre-conditioner or/and Al-bearing, FeSi inoculant application. 相似文献
15.
Jose M. Calderon Moreno Monica Popa Steliana Ivanescu Cora Vasilescu Silviu Iulian Drob Elena Ionela Neacsu Mihai V. Popa 《Metals and Materials International》2014,20(1):177-187
The corrosion behavior of a new, advanced Ti-20Zr alloy with α+β microstructure (determined by optical microscopy, XRD, and SEM) and very good mechanical properties (obtained from the stress-strain curve) is studied in this paper. The composition of the alloy native passive film was determined from a XPS analysis and the long-term corrosion resistance in undoped and doped states with 0.05M NaF artificial Carter-Brugirard saliva of different pH values, simulating the severe functional conditions of a dental implant, was analyzed by electrochemical methods. This alloy possesses an advantageous balance between good mechanical resistance and plasticity and Young’s modulus and exhibits more favorable electrochemical parameters and corrosion resistance than CP Ti due to its more resistant passive layer containing Ti2O3, TiO2, and ZrO2 protective oxides. After 1000 h of immersion in saliva, the protective properties of the alloy were enhanced due to the deposited surface layer that incorporated protective phosphates (shown by SEM and XPS). 相似文献
16.
Iulian Zoltan Boboescu Vasile Daniel Gherman Ion Mirel Bernadett Pap Roland Tengölics Gábor Rákhely Kornél L. Kovács Éva Kondorosi Gergely Maróti 《International Journal of Hydrogen Energy》2014
Biohydrogen production from synthetic wastewater as substrate was studied in anaerobic small scale batch reactors. Enriched anaerobic mixed consortia sampled from various environments were used as parent inocula to start the bioreactors. Selective enrichments were achieved by various physical and chemical pretreatments and changes in the microbial communities were monitored by metagenomic and molecular diagnostics approaches. Experimental data showed the feasibility of biohydrogen production using synthetic wastewater as substrate. The hydrogen generation capability of the different mixed consortia is clearly dependent on the pretreatment methods. The described approach opens the possibility for an alternative way towards simultaneous wastewater treatment and renewable energy generation. 相似文献
17.
The control problem associated to a class of horizontal-axis fixed-pitch variable-speed low-power wind energy conversion systems, working in the partial load region, consisting in the energy conversion maximization, is approached here under the assumption that the wind turbine model and its parameters are poorly known. Using a new approach derived from the optimum seeking methods category, generically called Maximum Power Point Tracking (MPPT), the proposed control solution aims at driving the average position of the operating point near to optimality. Instead of inducing sinusoidal search signals, the wind turbulence is here used as search disturbance. The high-speed shaft's average rotational speed is slowly adjusted using the Fast Fourier Transform processing of some available measures from the system as an estimate of the operating point's position/distance to optimality. Numerical simulations are used for preliminary checking the control law based on this estimation. 相似文献
18.
Silviu Olariu Roman Kolesov Farit Vagizov Olga Kocharovskaya 《Journal of Modern Optics》2013,60(6):877-884
We study the changes in the shape of the Mössbauer spectrum for the 21.5?keV transition of 151Eu3+ nuclei in a CaF2 lattice, assuming that a population of the excited electronic state 5 D 0 is maintained by optical pumping. For a population of the excited state 5 D 0 of 10%, we determine the magnitude of the changes in the Mössbauer spectrum as 1.9% of the area of the unperturbed spectrum. 相似文献
19.
M. V. Popa E. Vasilescu P. Drob I. Demetrescu B. Popescu D. Ionescu C. Vasilescu 《工业材料与腐蚀》2003,54(4):215-221
Long‐term monitoring (for 8000 exposure hours) of titanium and its implant alloys (Ti‐5Al‐4V, Ti‐6Al‐4Fe) interactions with Ringer's solutions of different pH‐values (2.5, 4.35, 6.98), simulating various conditions that can appear at the contact between implant and tissues was carried out in this paper. All data were statistics treated using Medcalc program. In vitro electrochemical behaviour of titanium and its alloys reveals their self‐passivation in Ringer's solutions. Monitoring of the open circuit potentials with time and pH have shown that the passive films on the implant materials studied were very stable for all tested periods. Interactions due to the non‐uniformity of the physiological electrolyte pH can not produce any form of local corrosion. The tested materials present low corrosion rates which attest their very good stability for 8000 exposure hours in simulated biological environment. Surface topography characterisation using atomic force microscopy (AFM) data, correlated with the electrochemical parameters, were arguments for the stability of the samples in studied bioliquids. 相似文献
20.
Cosmin Vasilica Pricope Bogdan Ionel Tamba Gabriela Dumitrita Stanciu Magdalena Cuciureanu Anca Narcisa Neagu Ioana Creanga-Murariu Bogdan-Ionut Dobrovat Cristina Mariana Uritu Silviu Iulian Filipiuc Bianca-Mariana Pricope Teodora Alexa-Stratulat 《International journal of molecular sciences》2022,23(21)
Chronic neuropathic pain (CNP) affects around 10% of the general population and has a significant social, emotional, and economic impact. Current diagnosis techniques rely mainly on patient-reported outcomes and symptoms, which leads to significant diagnostic heterogeneity and subsequent challenges in management and assessment of outcomes. As such, it is necessary to review the approach to a pathology that occurs so frequently, with such burdensome and complex implications. Recent research has shown that imaging methods can detect subtle neuroplastic changes in the central and peripheral nervous system, which can be correlated with neuropathic symptoms and may serve as potential markers. The aim of this paper is to review available imaging methods used for diagnosing and assessing therapeutic efficacy in CNP for both the preclinical and clinical setting. Of course, further research is required to standardize and improve detection accuracy, but available data indicate that imaging is a valuable tool that can impact the management of CNP. 相似文献