全文获取类型
收费全文 | 46篇 |
免费 | 0篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 16篇 |
金属工艺 | 1篇 |
机械仪表 | 2篇 |
建筑科学 | 2篇 |
矿业工程 | 1篇 |
能源动力 | 1篇 |
轻工业 | 8篇 |
无线电 | 2篇 |
一般工业技术 | 5篇 |
冶金工业 | 4篇 |
自动化技术 | 3篇 |
出版年
2024年 | 1篇 |
2022年 | 4篇 |
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2016年 | 2篇 |
2014年 | 1篇 |
2013年 | 3篇 |
2012年 | 3篇 |
2011年 | 10篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 4篇 |
2007年 | 3篇 |
2005年 | 1篇 |
2004年 | 2篇 |
1997年 | 1篇 |
1992年 | 1篇 |
排序方式: 共有46条查询结果,搜索用时 31 毫秒
1.
Halliday-Boykins Colleen A.; Henggeler Scott W.; Rowland Melisa D.; DeLucia Christian 《Canadian Metallurgical Quarterly》2004,72(6):993
The authors examined heterogeneity in symptom trajectories among youths following psychiatric crises as well as the psychosocial correlates and placement outcomes associated with identified trajectories. Using semiparametric mixture modeling with 156 youths approved for psychiatric hospitalization, the authors identified 5 trajectories based on symptoms over the 16 months following crisis: high improved, high unimproved, borderline improved, borderline unimproved, and subclinical. Membership in unimproved symptom groups was associated with less suicidality, younger age, more youth hopelessness, and more caregiver empowerment. Improved symptom group membership predicted long-term decreases in days in out-of-home placements. More important, and in contrast with general impressions from the existing literature, findings suggest that a substantive proportion of youths with serious emotional disturbance sustain high levels of symptomatology following intensive mental health services. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
2.
Journal of Porous Materials - The present study aims to investigate the effects of iron (hydr)oxide phases formed during precipitation and the addition of different binders on the mechanical and... 相似文献
3.
Portilla-Sangabriel Melisa Arzate Sandra Macías-Vargas José-Alberto Ramírez-Zamora Rosa-María 《Topics in Catalysis》2021,64(1-2):181-193
Topics in Catalysis - The use of the magnetic fraction (MF) of a low-grade titanium ore (TO) and two oxidants (H2O2 and NaClO), testing each one separately, were compared in photo-Fenton like... 相似文献
4.
Romina Fernández Varela Dr. Ana Laura Valino Dr. Eman Abdelraheem Dr. Rosario Médici Dr. Melisa Sayé Dr. Claudio A. Pereira Dr. Peter-Leon Hagedoorn Prof. Ulf Hanefeld Prof. Adolfo Iribarren Prof. Elizabeth Lewkowicz 《Chembiochem : a European journal of chemical biology》2022,23(13):e202200147
In nature 2-deoxy-D-ribose-5-phosphate aldolase (DERA) catalyses the reversible formation of 2-deoxyribose 5-phosphate from D-glyceraldehyde 3-phosphate and acetaldehyde. In addition, this enzyme can use acetaldehyde as the sole substrate, resulting in a tandem aldol reaction, yielding 2,4,6-trideoxy-D-erythro-hexapyranose, which spontaneously cyclizes. This reaction is very useful for the synthesis of the side chain of statin-type drugs used to decrease cholesterol levels in blood. One of the main challenges in the use of DERA in industrial processes, where high substrate loads are needed to achieve the desired productivity, is its inactivation by high acetaldehyde concentration. In this work, the utility of different variants of Pectobacterium atrosepticum DERA (PaDERA) as whole cell biocatalysts to synthesize 2-deoxyribose 5-phosphate and 2,4,6-trideoxy-D-erythro-hexapyranose was analysed. Under optimized conditions, E. coli BL21 (PaDERA C-His AA C49M) whole cells yields 99 % of both products. Furthermore, this enzyme is able to tolerate 500 mM acetaldehyde in a whole-cell experiment which makes it suitable for industrial applications. 相似文献
5.
Melisa Becerra Marcio S. Carvalho 《Chemical Engineering and Processing: Process Intensification》2011,50(5-6):445-449
Thin liquid sheets occur in several practical applications. In curtain coating, a thin liquid sheet is formed and falls freely over a considerable height before it impinges onto a moving substrate. Precision curtain coating was developed for multi layer photographic films but its use has expanded to many different applications. One of the important limits of this process is the stability of the liquid curtain, which may define the minimal thickness that can be coated at a given web speed.The condition at which a low viscosity Newtonian liquid curtain breaks was first derived based on a simple balance between inertial and capillary forces. There is a critical flow rate below which the curtain becomes unstable. For viscoelastic liquids, the normal stress related to the stretching of polymer molecules as the liquid accelerates down the curtain changes the force balance. Here, the critical condition at which a viscoelastic liquid curtain breaks was determined as a function of the rheological properties of the liquid. The results show that high extensional viscosity liquids create more stable curtains. Liquid additives could be used to push the limits of curtain flow rates to smaller values and consequently to widen the operability window of the process. 相似文献
6.
Films based on polylactic acid (PLA) reinforced with multi‐walled carbon nanotubes (MWCNT) were developed after using an excellent methodology to ensure an optimum dispersion of the filler in the matrix. The functionalization of MWCNT was carried out through a Fenton reaction to generate hydroxyl (OH) and carboxyl (COOH) groups on their walls. After that, COOH groups were lengthened by reacting with thionyl chloride and then with triethylene glycol to achieve a terminal OH distanced from the wall of the MWCNT. Nanocomposites based on PLA containing different concentrations of functionalized filler (fMWCNT: 0.026, 0.10, and 0.18 wt%) were prepared by casting. The influence of filler concentration was investigated using some techniques such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT‐IR), thermogravimetric analysis (TGA), water vapor permeability (WVP) and uniaxial tensile mechanical properties. Excellent dispersion of fMWCNT was observed suggesting that the technique of functionalization used was appropriate. All nanocomposites presented great stability, allowing them to be processed to temperatures reaching 300°C. Furthermore, an increasing trend of ultimate tensile strength (σu) up to 20% and a decrease of WVP around 40% with the addition of only 0.10 wt% of fMWCNT were obtained. Considering these results, the new biodegradable nanocomposites developed in this work could be very promising to replace synthetic plastics that currently are used in different areas such as nanotechnology, packaging and biomedicine. POLYM. COMPOS., 37:3066–3072, 2016. © 2015 Society of Plastics Engineers 相似文献
7.
Coupled transport of thiocyanate ions through a liquid membrane containing quaternary ammonium chloride salts in chloroform was examined. The influences of the carrier type in the membrane phase on the coupled transport of thiocyanate ions were investigated. The kinetics of the coupled transport were analyzed in the formalism of two consecutive irreversible first-order reactions and the kinetic parameters (k1d, k2m, k2a, Rmmax, tmax, Jdmax, Jamax) were also calculated. For the coupled transport of thiocyanate ions, quaternary ammonium chloride salts having different carbon atom numbers (Cn) used as carriers were found to increase thiocyanate ions transport efficiency with increasing carbon atom numbers. Tetradecyl trimethylammonium chloride (TDTMACl), hexadecyl trimethylammonium chloride (HDTMACl), and tetraoctyl ammonium chloride (TOACl) were found to be the most effective carrier types for transport of thiocyanate ions when Cn is greater than 16. The activation energies for maximum membrane entrance and exit fluxes were calculated as 32.45 kJ/mol and 34.75 kJ/mol, respectively. The values of the activation energy indicate that the process is controlled by species diffusion. 相似文献
8.
Ö. Demircioglu?. Karata? N. Y?ld?r?mÖ.F. Bakkaloglu 《Microelectronic Engineering》2011,88(9):2997-3002
Temperature dependences of the series resistance in the Cr/n-Si/Au-Sb Schottky structures prepared by electrodeposition method have been studied using current-voltage (I-V) characteristics in the 80-320 K temperature range by steps of 20 K. However, the values of series resistance obtained from Cheung functions were compared with each other, and it was seen that there is a good agreement between the values of the series resistance. A modified Norde’s function combined with conventional forward I-V method was used to extract the parameters including barrier height and the series resistance. The barrier height and series resistance obtained from Norde’s function were compared with those from Cheung functions. The values of barrier height and series resistance have very different especially towards to the lower temperatures. This is attributed to non-ideal I-V characteristics of the Cr/n-Si/Au-Sb Schottky structure and non-pure thermionic emission theory due to the low temperature effects. 相似文献
9.
Melisa E. Lamanna Enrique de la Horra Silvia Jacobo Norma B. DAccorso 《Reactive and Functional Polymers》2009,69(10):759-765
We performed the polymerization of 3-amino-1,2,4-triazole (ATA), an insulator material, in acidic aqueous solution with ammonium persulfate, as oxidant agent. The new material, conveniently doped, turned out to be a semiconductor tetramer. The characterization was carried out using physical and spectroscopic techniques (elemental analysis, infrared spectroscopy, 1H NMR, 13C NMR and mass spectra). Thermogravimetric analysis (TGA) indicated that this oligomer enhances thermal stability of starting material. The room temperature electrical conductivity of the synthesized oligomer (OATA) was 3.1 × 10−4 S cm−1.The kinetic polymerization was analyzed by UV–vis spectroscopy, taking into account the pH dependence, monomer–oxidant ratio and monomer concentration. A possible polymerization mechanism was proposed. 相似文献
10.
Wilson EJ Morgan MG Apt J Bonner M Bunting C Gode J Haszeldine RS Jaeger CC Keith DW Mccoy ST Pollak MF Reiner DM Rubin ES Torvanger A Ulardic C Vajjhala SP Victor DG Wright IW 《Environmental science & technology》2008,42(8):2718-2722
Governments worldwide should provide incentives for initial large-scale GS projects to help build the knowledge base for a mature, internationally harmonized GS regulatory framework. Health, safety, and environmental risks of these early projects can be managed through modifications of existing regulations in the EU, Australia, Canada, and the U.S. An institutional mechanism, such as the proposed Federal Carbon Sequestration Commission in the U.S., should gather data from these early projects and combine them with factors such as GS industrial organization and climate regime requirements to create an efficient and adaptive regulatory framework suited to large-scale deployment. Mechanisms to structure long-term liability and fund long-term postclosure care must be developed, most likely at the national level, to equitably balance the risks and benefits of this important climate change mitigation technology. We need to do this right. During the initial field experiences, a single major accident, resulting from inadequate regulatory oversight, anywhere in the world, could seriously endanger the future viability of GS. That, in turn, could make it next to impossible to achieve the needed dramatic global reductions in CO2 emissions over the next several decades. We also need to do it quickly. Emissions are going up, the climate is changing, and impacts are growing. The need for safe and effective CO2 capture with deep GS is urgent. 相似文献