全文获取类型
收费全文 | 43篇 |
免费 | 1篇 |
专业分类
化学工业 | 2篇 |
金属工艺 | 1篇 |
轻工业 | 2篇 |
无线电 | 6篇 |
一般工业技术 | 9篇 |
冶金工业 | 13篇 |
原子能技术 | 1篇 |
自动化技术 | 10篇 |
出版年
2023年 | 1篇 |
2016年 | 3篇 |
2015年 | 1篇 |
2011年 | 4篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2003年 | 1篇 |
1999年 | 1篇 |
1998年 | 5篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 1篇 |
排序方式: 共有44条查询结果,搜索用时 15 毫秒
21.
The chemical species involved in the adhesion of blue mussels (Mytilus galloprovincialis) and greenshell mussels (Perna canaliculus) to surfaces has been investigated using in situ attenuated total reflection infrared (ATR-IR) spectroscopy. Mussel spat ranging in size from 0.5 to 25 mm were placed in a flow cell containing a ZnSe multiple internal reflection prism and supplied with temperature-controlled seawater. Distinctively different absorption spectra were obtained when the mussels were predominantly moving across the surface or forming permanent bonds. With limited movement, the absorption spectrum was characteristic of protein with peaks near 1647 cm-1 (amide I), 1543 cm-1 (amide II), and 1235 cm-1 (amide III). When the mussels were observed to be moving across the surface of the ATR-IR crystal there was a strong broad absorption maximum around 1200-900 cm-1 (carbohydrate polymers), presumably due to the secretion of a weakly acidic mucopolysaccharide. Distinct differences in the spectra obtained from the adhesive secretions of blue or greenshell mussels were not observed. The data presented is the first reported use of IR spectroscopy to obtain in situ, real-time, chemical data on the interactions between invertebrates and substrates immersed in sea water. 相似文献
22.
The family of stichotrichous ciliates contains several single-celled organisms
possessing a unique genetic mechanism: the ability to descramble genes which exist in a scrambled state in their genomes.
We continue the theoretical investigation of the iterated template-guided recombination operation. This operation is suggested
by
the recombination of DNA strands based on template guides proposed by Prescott, Ehrenfeucht and Rozenberg. A variety of results
is demonstrated including a study of computational power, characterizations and other abstract properties, such as a "pumping
lemma". The notion of a useful template is defined and forms a critical basis for much of the results demonstrated in the
paper. The main result shows that every full AFL is closed under iterated template-guided recombination with regular templates. 相似文献
23.
The increasing use of computer data communications over the past several years has spawned a variety of network architectures to support requirements for distributed processing. Developed by various R&D groups,1-3by the common carriers,4-4by minicomputer and mainframe manufacturers,7,8and by the vendors of traditional communications hardware,9,10these new architectures represent alternative means to similar ends. This article provides a framework for understanding existing and forthcoming systems, focusing particular attention on the impact of evolving requirements and technologies. 相似文献
24.
25.
Masood S. Alivand Rebecca V. McQuillan Arash Momeni Ali Zavabeti Geoffrey W. Stevens Kathryn A. Mumford 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(30):2300150
Direct removal of carbon dioxide (CO2) from the atmosphere, known as direct air capture (DAC) is attracting worldwide attention as a negative emission technology to control atmospheric CO2 concentrations. However, the energy-intensive nature of CO2 absorption-desorption processes has restricted deployment of DAC operations. Catalytic solvent regeneration is an effective solution to tackle this issue by accelerating CO2 desorption at lower regeneration temperatures. This work reports a one-step synthesis methodology to prepare monodispersed carbon nanospheres (MCSs) using trisodium citrate as a structure-directing agent with acidic sites. The assembly of citrate groups on the surface of MCSs enables consistent spherical growth morphology, reduces agglomeration and enhances water dispersibility. The functionalization-assisted synthesis produces uniform, hydrophilic nanospheres of 100–600 nm range. This work also demonstrates that the prepared MCSs can be further functionalized with strong Brønsted acid sites, providing high proton donation ability. Furthermore, the materials can be effectively used in a wide range of amino acid solutions to substantially accelerate CO2 desorption (25.6% for potassium glycinate and 41.1% for potassium lysinate) in the DAC process. Considering the facile synthesis of acidic MCSs and their superior catalytic efficiency, these findings are expected to pave a new path for energy-efficient DAC. 相似文献
26.
RV Iozzo DK Moscatello DJ McQuillan I Eichstetter 《Canadian Metallurgical Quarterly》1999,274(8):4489-4492
Ectopic expression of decorin induces profound cytostatic effects in transformed cells with diverse histogenetic backgrounds. The mechanism of action has only recently begun to be elucidated. Exogenous decorin activates the epidermal growth factor (EGF) receptor, thereby triggering a signaling cascade that leads to phosphorylation of mitogen-activated protein (MAP) kinase, induction of p21, and growth suppression. In this study we demonstrate a direct interaction of decorin with the EGF receptor. Binding of decorin induces dimerization of the EGF receptor and rapid and sustained phosphorylation of MAP kinase in squamous carcinoma cells. In a cell-free system, decorin induces autophosphorylation of purified EGF receptor by activating the receptor tyrosine kinase and can also act as a substrate for the EGF receptor kinase itself. Using radioligand binding assays we show that both immobilized and soluble decorin bind to the EGF receptor ectodomain or to purified EGF receptor. The binding is mediated by the protein core and has relatively low affinity (Kd approximately 87 nM). Thus, decorin should be considered as a novel biological ligand for the EGF receptor, an interaction that could regulate cell growth during remodeling and cancer growth. 相似文献
27.
Depth-synchronization measures the number of parallel derivation steps in a synchronized context-free (SCF) grammar. When not bounded by a constant the depth-synchronization measure of an SCF grammar is at least logarithmic and at most linear with respect to the word length. Languages with linear depth-synchronization measure and languages with a depth-synchronization measure in between logarithmic and linear are proven to exist. This gives rise to a strict infinite hierarchy within the family of SCF (and ET0L) languages. 相似文献
28.
29.
The adsorption of alginic acid on a TiO(2) particle film from aqueous solution was investigated by attenuated total reflection infrared (ATR-IR) spectroscopy. ATR-IR spectra recorded at different pHs confirmed that alginate adsorption to TiO(2) is favored at pH 3.0 and no significant adsorption occurs above pH 5.0. Upon adsorption the carboxylic acid groups of alginic acid are converted to the carboxylate form and bind to surface Ti(IV) ions via bridging bidentate structures. Spectral analyses of the carboxylic acid and carboxylate stretching vibrations indicated that about three in four -COOH groups are converted to -COO(-) groups as they bind coordinately to TiO(2). Additionally, the spectral data at pH 8.0 showed specific interactions of Ca(2+) ions with the free COO(-) groups of the polysaccharide backbone of adsorbed alginic acid. 相似文献
30.