全文获取类型
收费全文 | 72篇 |
免费 | 6篇 |
专业分类
化学 | 61篇 |
数学 | 2篇 |
物理学 | 8篇 |
无线电 | 7篇 |
出版年
2023年 | 1篇 |
2021年 | 5篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2014年 | 4篇 |
2013年 | 4篇 |
2012年 | 1篇 |
2011年 | 4篇 |
2010年 | 6篇 |
2009年 | 2篇 |
2008年 | 7篇 |
2007年 | 3篇 |
2006年 | 8篇 |
2005年 | 3篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 2篇 |
1996年 | 3篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有78条查询结果,搜索用时 390 毫秒
1.
John A. Mikroyannidis Helen A. Moshopoulou John A. Anastasopoulos Minas M. Stylianakis Larysa Fenenko Chihaya Adachi 《Journal of polymer science. Part A, Polymer chemistry》2006,44(23):6790-6800
Poly(9,9‐dihexylfluorene‐2,7‐vinylene‐alt‐dibenzothiophene‐2,8‐vinylene) (PS) and poly(9,9‐dihexylfluorene‐2,7‐vinylene‐alt‐dibenzothiophene‐5,5‐dioxide‐2,8‐ vinylene) (PSO) as well as corresponding model compounds were synthesized by Heck coupling. Both the polymers and model compounds were readily soluble in common organic solvents such as tetrahydrofuran, dichloromethane, chloroform, and toluene. The polymers showed a decomposition temperature at ~430 °C and a char yield of about 65% at 800 °C in N2. The glass‐transition temperatures of the polymers were almost identical (75–77 °C) and higher than those of the model compounds (26–45 °C). All samples absorbed around 390 nm, and their optical band gaps were 2.69–2.85 eV. They behaved as blue‐greenish light emitting materials in both solutions and thin films, with photoluminescence emission maxima at 450–483 nm and photoluminescence quantum yields of 0.52–0.72 in solution. Organic light‐emitting diodes with an indium tin oxide/poly(ethylene dioxythiophene):poly(styrene sulfonic acid)/polymer/Mg:Ag/Ag configuration with polymers PS and PSO as emitting layers showed green electroluminescence with maxima at 530 and 540 nm, respectively. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6790–6800, 2006 相似文献
2.
Pinto SS Diogo HP Guedes RC Costa Cabral BJ Minas da Piedade ME Martinho Simões JA 《The journal of physical chemistry. A》2005,109(42):9700-9708
The energetics of the phenolic O-H bond in the three hydroxybenzoic acid isomers and of the intramolecular hydrogen O-H- - -O-C bond in 2-hydroxybenzoic acid, 2-OHBA, were investigated by using a combination of experimental and theoretical methods. The standard molar enthalpies of formation of monoclinic 3- and 4-hydroxybenzoic acids, at 298.15 K, were determined as Delta(f)(3-OHBA, cr) = -593.9 +/- 2.0 kJ x mol(-1) and Delta(f)(4-OHBA, cr) = -597.2 +/- 1.4 kJ x mol(-1), by combustion calorimetry. Calvet drop-sublimation calorimetric measurements on monoclinic samples of 2-, 3-, and 4-OHBA, led to the following enthalpy of sublimation values at 298.15 K: Delta(sub)(2-OHBA) = 94.4 +/- 0.4 kJ x mol(-1), Delta(sub)(3-OHBA) = 118.3 +/- 1.1 kJ x mol(-1), and Delta(sub)(4-OHBA) = 117.0 +/- 0.5 kJ x mol(-1). From the obtained Delta(f)(cr) and Delta(sub) values and the previously reported enthalpy of formation of monoclinic 2-OHBA (-591.7 +/- 1.3 kJ x mol(-1)), it was possible to derive Delta(f)(2-OHBA, g) = -497.3 +/- 1.4 kJ x mol(-1), Delta(f)(3-OHBA, g) = -475.6 +/- 2.3 kJ x mol(-1), and Delta(f)(4-OHBA, cr) = -480.2 +/- 1.5 kJ x mol(-1). These values, together with the enthalpies of isodesmic and isogyric gas-phase reactions predicted by density functional theory (B3PW91/aug-cc-pVDZ, MPW1PW91/aug-cc-pVDZ, and MPW1PW91/aug-cc-pVTZ) and the CBS-QMPW1 methods, were used to derive the enthalpies of formation of the gaseous 2-, 3-, and 4-carboxyphenoxyl radicals as (2-HOOCC(6)H(4)O(*), g) = -322.5 +/- 3.0 kJ.mol(-1) Delta(f)(3-HOOCC(6)H(4)O(*), g) = -310.0 +/- 3.0 kJ x mol(-1), and Delta(f)(4-HOOCC(6)H(4)O(*), g) = -318.2 +/- 3.0 kJ x mol(-1). The O-H bond dissociation enthalpies in 2-OHBA, 3-OHBA, and 4-OHBA were 392.8 +/- 3.3, 383.6 +/- 3.8, and 380.0 +/- 3.4 kJ x mol(-1), respectively. Finally, by using the ortho-para method, it was found that the H- - -O intramolecular hydrogen bond in the 2-carboxyphenoxyl radical is 25.7 kJ x mol(-1), which is ca. 6-9 kJ x mol(-1) above the one estimated in its parent (2-OHBA), viz. 20.2 kJ x mol(-1) (theoretical) or 17.1 +/- 2.1 kJ x mol(-1) (experimental). 相似文献
3.
The stereospecific formation of the 5H-pyrano[3,2-d]oxazole-2,6-dione ring system from 2,2-disubstituted-6-[[(methylamino)carbonyl]oxy]-2H-pyran-3(6H)-one via an enolization at C-5 is presented. The outcome of the same reaction in the case of 2-monosubstituted 2H-pyran-3(6H)-ones is also discussed. 相似文献
4.
Dasygenis M. Brockmeyer E. Durinck B. Catthoor F. Soudris D. Thanailakis A. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2006,14(3):279-291
Memory latency has always been a major issue in embedded systems that execute memory-intensive applications. This is even more true as the gap between processor and memory speed continues to grow. Hardware and software prefetching have been shown to be effective in tolerating the large memory latencies inherit in large off-chip memories; however, both types of prefetching have their shortcomings. Hardware schemes are more complex and require extra circuitry to compute data access strides, while software schemes generate prefetch instructions, which if not computed carefully may hamper performance. On the other hand, some applications domains (such as multimedia) have a uniform and known a priori memory access pattern, that if exploited, could yield significant application performance improvement. With this characteristic in mind, we present our findings on hiding memory latency using the direct memory access (DMA) mode, which is present in all modern systems, combined with a software prefetch mechanism, and a customized on-chip memory hierarchy mapping. Compared to previous approaches, we are able to estimate the performance and power metrics, without actually implementing the embedded system. Experimental results on nine well known multimedia and imaging applications prove the efficiency of our technique. Finally, we verify the performance estimations by implementing and simulating the algorithms on the TI C6201 processor. 相似文献
5.
Dr. Julia Stroh Torvid Feiler Dr. Naveed Zafar Ali Prof. Manuel E. Minas da Piedade Dr. Franziska Emmerling 《ChemistryOpen》2019,8(7):1012-1019
Mechanochemistry offers an environmentally benign and facile synthesis method for a variety of cement paste constituents. In addition, these methods can be used to selectively tune the properties of cement components. The mineral ettringite is an important component of cementitious materials and has additional technological potential due to its ion exchange properties. Synthesis of ettringite via mechanochemistry is an environmentally friendly alternative to conventional wet-chemical synthesis established in industry. This contribution explores the mechanism of a two-step mechanochemical synthesis of ettringite, which was previously found to greatly improve the reaction conversion as compared with one-pot synthesis. The crystallinity of Al(OH)3 was found to decrease during the first stage of this mechanochemical synthesis. This was correlated to a significant decrease in the particle size of Al(OH)3 in this stage. No other significant changes were found for the other components, suggesting that mechanochemical activation of Al(OH)3 is responsible for the enhanced formation of ettringite by the two-step approach. The environmentally friendly approach developed for ettringite synthesis offers a versatile synthetic strategy, which can be applied to synthesise further cementitious materials. 相似文献
6.
Eirini Chrysochou Panagiotis Georgios Kanellopoulos Konstantinos G. Koukoulakis Aikaterini Sakellari Sotirios Karavoltsos Minas Minaidis Evangelos Bakeas 《Molecules (Basel, Switzerland)》2021,26(11)
Cardiovascular diseases (CVDs) have been associated with environmental pollutants. The scope of this study is to assess any potential relation of polycyclic aromatic hydrocarbons (PAHs), their hydroxylated derivatives, and trace elements with heart failure via their direct determination in human serum of Greek citizens residing in different areas. Therefore, we analyzed 131 samples including cases (heart failure patients) and controls (healthy donors), and the respective demographic data were collected. Significantly higher concentrations (p < 0.05) were observed in cases’ serum regarding most of the examined PAHs and their derivatives with phenanthrene, fluorene, and fluoranthene being the most abundant (median of >50 μg L−1). Among the examined trace elements, As, Cd, Cu, Hg, Ni, and Pb were measured at statistically higher concentrations (p < 0.05) in cases’ samples, with only Cr being significantly higher in controls. The potential impact of environmental factors such as smoking and area of residence has been evaluated. Specific PAHs and trace elements could be possibly related with heart failure development. Atmospheric degradation and smoking habit appeared to have a significant impact on the analytes’ serum concentrations. PCA–logistic regression analysis could possibly reveal common mechanisms among the analytes enhancing the hypothesis that they may pose a significant risk for CVD development. 相似文献
7.
From superhydrophobic‐ to superhydrophilic‐patterned poly(vinylidene fluoride‐co‐chlorotrifluoroethylene) architectures as a novel platform for biotechnological applications
下载免费PDF全文
![点击此处可从《Journal of Polymer Science.Polymer Physics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Vanessa F. Cardoso Ana R. Machado Vânia C. Pinto Paulo J. Sousa Gabriela Botelho Graça Minas Senentxu Lanceros‐Méndez 《Journal of Polymer Science.Polymer Physics》2016,54(18):1802-1810
The manufacture of three‐dimensional patterned electroactive poly(vinylidene fluoride‐co‐chlorotrifluoroethylene) microstructures with tailored architecture, morphology, and wettability is presented. The patterned microstructures are fabricated using a simple, effective, low cost, and reproducible technique based on microfluidic technology. These novel structures can represent innovative platforms for advanced strategies in a wide range of biotechnological applications, including tissue engineering, drug delivery, microfluidic, and sensors and actuators devices. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1802–1810 相似文献
8.
Nikolaos Kroupis Nikolaos Zervas Minas Dasygenis Konstantinos Tatas Antonios Argyriou Dimitrios Soudris Antonios Thanailakis 《The Journal of VLSI Signal Processing》2006,44(1-2):153-171
The continuous increase of the computational power of programmable processors has established them as an attractive design
alternative, for implementation of the most computationally intensive applications, like video compression. To enforce this
trend, designers implementing applications on programmable platforms have to be provided with reliable and in-depth data and
instruction analysis that will allow for the early selection of the most appropriate application for a given set of specifications.
To address this need, we introduce a new methodology for early and accurate estimation of the number of instructions required
for the execution of an application, together with the number of data memory transfers on a programmable processor. The high-level
estimation is achieved by a series of mathematical formulas; these describe not only the arithmetic operations of an application,
but also its control and addressing operations, if it is executed on a programmable core. The comparative study, which is
done using three popular processors (ARM, MIPS, and Pentium), shows the high efficiency and accuracy of the methodology proposed,
in terms of the number of executed (micro-)instructions (i.e. performance) and the number of data memory transfers (i.e. memory
power consumption). Using the proposed methodology we estimated an average deviation of 23% in our estimated figures compared
with the measurements taken from the real execution on the CPUs.
This work was supported by the project PENED ’99 ED501 funded by GSRT of the Greek Ministry of Development, and the project
PRENED ’99 KE 874 funded by the Research Committee of the Democritus University of Thrace. This work was partially sponsored
by a scholarship from the Public Benefit Foundation of Alexander S. Onassis (Minas Dasygenis).
Nikolaos Kroupis was born in Trikala in 1976. He receiver the engineering degree and Ms.C. degree in Department of Electrical and Computer
Engineering from Democritous University of Thrace, Greece, in 2000 and 2002, respectively. Since 2002 he has been a Ph.D.
student at the Laboratory of Electrical and Electronic Materials Technology. His research interests are in software/hardware
co-design of embedded system for signal processing applications.
Nikos D. Zervas received a Diploma in Electrical & Computer Engineering from University of Patras, Greece in 1997. He received the Ph.D.
degree in the Department of Electrical and Computer Engineering of the same University in 2004. His research interests are
in the area of high-level, power optimization techniques and methodologies for multimedia and telecommunication applications.
He has received an award from IEEE Computer Society in the context of Low-Power Design Contest of 2000 IEEE Computer Elements
Mesa Workshop. Mr. Zervas is a member of the IEEE, ACM and of the Technical Chamber of Greece.
Minas Dasygenis was born in Thessaloniki in 1976. He received his Diploma in Electrical and Computer Engineering in 1999, from the Democritus
University of Thrace, Greece, and for his diploma Thesis he was honored by The Technical Chamber of Greece and Ericsson Hellas.
In 2005, he received his PhD Degree from the Democritus University of Thrace. His research interests include low-power VLSI
design of arithmetic circuits, residue number system, embedded architectures, DSPs, hardware/ software codesign and IT security.
He has published more than 20 papers in international journals and conferences and he has been a principal researcher in three
European research projects.
Konstantinos Tatas received his degree in Electrical and Computer Engineering from the Democritus University of Thrace, Greece in 1999. He received
his Ph.D. in the VLSI Design and Testing Center in the same University by June 2005. He has been employed as an RTL designer
in INTRACOM SA, Greece between 2000 and 2003. His research interests include low-power VLSI design of DSP and multimedia systems,
computer arithmetic, IP core design and design for reuse.
Antonios Argyriou received the degree in Electrical and Computer engineering from the Democritous University of Thrace, Greece, in 2001, and
the M.S. and Ph.D. degrees in Electrical and Computer engineering from the Georgia Institute of Technology, Atlanta, in 2003
and 2005, respectively. His primary research interests include wireless networks, mobile computing and multimedia communications.
He is a member of the IEEE and ACM.
Dimitrios Soudris received his Diploma in Electrical Engineering from the University of Patras, Greece, in 1987. He received the Ph.D. Degree
in Electrical Engineering, from the University of Patras in 1992. He is currently working as Ass. Professor in Dept. of Electrical
and Computer Engineering, Democritus University of Thrace, Greece. His research interests include low power design, parallel
architectures, embedded systems design, and VLSI signal processing. He has published more than 140 papers in international
journals and conferences. He was leader and principal investigator in numerous research projects funded from the Greek Government
and Industry as well as the European Commission (ESPRIT II-III-IV and 5th and 6th IST). He has served as General Chair and
Program Chair for the International Workshop on Power and Timing Modelling, Optimisation, and Simulation (PATMOS). He received
an award from INTEL and IBM for the project results of LPGD #25256 (ESPRIT IV). He is a member of the IEEE, the VLSI Systems
and Applications Technical Committee of IEEE CAS and the ACM.
Antonios Thanailakis was born in Greece on August 5, 1940. He received B.Sc. degrees in physics and electrical engineering from the University
of Thessaloniki, Greece, 1964 and 1968, respectively, and the Msc. and Ph.D. Degrees in electrical engineering and electronics
from UMIST, Manchester, U.K. in 1968 and 1971, respectively. He has been a Professor of Microelectronics in Dept. of Electrical
and Computer Eng., Democritus Univ. of Thrace, Xanthi, Greece, since 1977. He has been active in electronic device and VLSI
system design research since 1968. His current research activities include microelectronic devices and VLSI systems design.
He has published a great number of scientific and technical papers, as well as five textbooks. He was leader for carrying
out research and development projects funded by Greece, EU, or other organizations on various topics of Microlectronics and
VLSI Systems Design (e.g. NATO, ESPRIT, ACTS, STRIDE). 相似文献
9.
Minas P. Georgiadis Violetta Constantinou-Kokotou George Kokotos 《Journal of carbohydrate chemistry》2013,32(5):739-748
ABSTRACT 6′-N derivatives of neamine with alanine, phenylalanine and lysine were synthesized either using an active esters method in one step under controlled conditions, or using a mixed anhydride method after blocking every functional group of neamine and leaving the 6′-amino group free to react. Similarly N,N′-diamino acid and monoamino acid derivatives of 2-deoxystreptamine were synthesized. 相似文献
10.
R. M. Minas’yan 《Polymer Science Series D》2011,4(3):206-208
Single-component silicon adhesive sealant of cold vulcanization based on liquid polyorganosiloxane resins with terminal hydroxyl
groups designed at the State Research Institute of Chemistry and Technology of Organoelement Compounds are presented. It was
demonstrated that due to their high performance characteristics, in particular the wide range of working temperatures (from
−90 to +300°C), these materials draw interest from both civilian and special fields of industry. Methods of producing single-component
silicon adhesive sealants were considered. 相似文献