全文获取类型
收费全文 | 271篇 |
免费 | 7篇 |
专业分类
电工技术 | 5篇 |
化学工业 | 52篇 |
金属工艺 | 5篇 |
机械仪表 | 4篇 |
建筑科学 | 8篇 |
能源动力 | 24篇 |
轻工业 | 33篇 |
石油天然气 | 4篇 |
无线电 | 20篇 |
一般工业技术 | 55篇 |
冶金工业 | 21篇 |
原子能技术 | 2篇 |
自动化技术 | 45篇 |
出版年
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 11篇 |
2020年 | 8篇 |
2019年 | 6篇 |
2018年 | 11篇 |
2017年 | 11篇 |
2016年 | 12篇 |
2015年 | 8篇 |
2014年 | 10篇 |
2013年 | 21篇 |
2012年 | 17篇 |
2011年 | 18篇 |
2010年 | 14篇 |
2009年 | 7篇 |
2008年 | 13篇 |
2007年 | 8篇 |
2006年 | 10篇 |
2005年 | 6篇 |
2004年 | 3篇 |
2003年 | 8篇 |
2002年 | 1篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 9篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 5篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1976年 | 3篇 |
1974年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有278条查询结果,搜索用时 31 毫秒
201.
Microstructure and plastic behavior of poly(lactic acid), PLA, and poly(ε-caprolactone), PCL, are investigated. The injected molded specimens are analyzed as received. Thermomechanical properties are characterized by DSC and DMA and crystalline structure by WAXS. The results show that PLA samples are weakly crystalline (14 wt%) and that amorphous phase is glassy at room temperature. The PCL samples exhibit higher crystallinity (53 wt%) and contain a rubber-like amorphous phase. Mechanical behavior is investigated by means of novel video-controlled materials testing system specially developed to assess true stress vs. true strain curves and to record the volume changes upon stretching. While tested at 50 °C, PLA undergoes extensive plastic deformation with a dramatic yield softening followed by a progressively increasing strain hardening. Volume strain, which characterizes deformation damage, increases steadily over the whole plastic stage until reaching 0.27 for an axial strain of 1, 4. For its part, PCL exhibits at 23 °C a much progressive plastic response with a soft yield point, no softening, and moderate strain hardening at large strain. Volume change is delayed until axial strain reaches 0.4. Subsequent damage grows very quickly, eventually reaching 0.2 for an ultimate strain of 1, 3. Results are discussed on the basis of microscopic damage mechanisms observed in the stretched state. 相似文献
202.
I. Kashif H. Farouk S. H. Salah A. A. Abdel Rahman A. M. Sanad 《Journal of Materials Science: Materials in Electronics》1991,2(4):220-222
A glass system was prepared from reagent grade chemicals having the formula 58 mol % B2O3 - 22 mol % CaO - (20 - ) mol % Al2O3 - mol % Fe2O3, where has different values between 2 and 20 mol %.The molar volume () and magnetic susceptibility () of these glasses has been measured as a function of Fe2O3 content. The values of and were found to increase as the Fe2O3 content in the glass increases in the region between 2 and 8 mol % and in the region where the content is greater than 10 to 16 mol %, while a decrease was found for samples having an Fe2O3 content of 10 mol % and more than 16 mol %. These results could be explained by the change in coordination of iron from FeO6 to FeO4, and also the change of Fe3+ to Fe2+ and change of Fe2+ from six coordination to four coordination. 相似文献
203.
A new bifunctional reactive disperse dye containing a temporarily anionic sulphatoethylsulphone and a nonionic disulphide bis(ethylsulphone) groups was synthesised and applied to nylon 6 fabric by the exhaust dyeing at a variety of pH and temperature conditions. A monofunctional reactive disperse dye containing only nonionic disulphide bis(ethylsulphone) group was also synthesised and its dyeing behaviour was compared with the bifunctional dye. The bifunctional reactive disperse dye exhibited high exhaustion and fixation values at pH 6 and 120 °C. The results also indicate that the combination of temporarily anionic and nonionic reactive groups of the bifunctional dye provided great enhancement in dyeing performance compared to that of the monofunctional dye. The dyes also showed very good levelling and fastness properties on nylon 6 fabric. 相似文献
204.
Raouf S. H. Mikhail Suzy A. Selim Farouk I. Zeidan 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1976,26(1):191-198
The surface properties of a stannic oxide gel and its thermal dehydration products obtained both in vacuo and in the presence of air in the temperature range 100–600°C have been examined by N2 adsorption. Phase and structural changes have been followed by differential thermal analysis and X-ray diffractometry. Complete pore structure analysis showed that samples dehydrated at or below 250°C were microporous. Above 250°C the pores were found to widen with increase of temperature, the widening occurring concurrently with the crystallisation process. Doping with cations of lower valency (Li+ and Al3+) than the host cation (Sn4+) had little effect on the pore structure and specific surface area for the low temperature samples (≥250°), whereas at higher temperatures, e.g. 600°C, it increased the specific area remarkably. The dope ions produce oxygen vacancies and hinder or retard sintering in SnO2. 相似文献
205.
A. Elsebaei J. Heberlein M. Elshaer A. Farouk 《Journal of Thermal Spray Technology》2010,19(1-2):2-10
The relationship between atmospheric pressure plasma spray parameters and in-flight particle characteristics was determined. The morphologies of individual splats and the coating microstructure were studied for different stand-off distances and arc currents. Coating cross-sectional analysis showed that the total porosity of the coating increased with decreasing arc current, and increasing stand-off distance. Two different materials were used: the regular (r-YSZ) feed stock and the nano size (n-YSZ) agglomerated powder. The results illustrate that the r-YSZ coating has higher total porosity at higher arc currents than n-YSZ coating. The splat flattening degree and circularity was examined at different substrate temperatures for both powders. The results indicate that the flattening degree increased at high temperatures for the two materials, but the values for n-YSZ were higher than those for the r-YSZ. This study showed the operating regimes in which the use of n-YSZ yields improved coating properties. 相似文献
206.
A Li–borate glass system doped with samarium and europium has been prepared by a conventional melt quenching technique. Europium content was kept constant at 0.01 mol%. The general formula waswhere x = 0.1, 0.2, 0.5, 0.6 and 0.7 mol%. The density was measured and the corresponding molar volume was evaluated .The former was found to increase by increasing Sm while the later exhibits opposite trend. The average optical basicity, Λth, electron negativity χ2av and electron polarizability α2− were calculated for the prepared compositions. Infrared spectra were obtained at room temperature for the prepared glasses before and after γ irradiation. The results showed that the three main appeared bands are most likely due to the bending and/or stretching vibration of both tetrahedral BO4 and triagonal BO3 borate units. ESR spectra were recorded at room temperature before and after γ-irradiation. It was found that the oxygen atoms of BO3 units are responsible for the formation of the hole paramagnetic centers after irradiation in the glass matrix. 相似文献
xSm2O3 + (100 − x) [0.84B2O3 + 0.15Li2O + 0.01Eu2O3]
207.
The effect of rigor temperature (RT, 35 versus 10°C), increased ionic concentration (MS: 0 versus 0·2% mixed salts), oxidized lipids (OL, 0 versus 1% added oxidized fat), increased free amino acids (FAA, 0 versus 0·3% added mixture of amino acids), fat content (FC, 0 versus 15% added fat) and excluding atmospheric gases (V, 0 versus 99·9% vacuum) on protein functionality in mince stored 1 month at -20°C was studied using a complete 2(6) factorial design. All factors studied affected the functional properties of beef. Fresh 24hr samples that entered rigor at 35°C had lower total (TPS), myofibrillar (MPS) and sarcoplasmic (SPS) protein solubilities than samples entering rigor at 10°C (p<0·01). During frozen storage, RT, MS and OL alone did not affect protein solubilities, FAA increased TPS but did not affect MPS and SPS, increasing the meat's fat content raised TPS and SPS but did not affect MPS, applying a vacuum increased TPS and MPS but lowered SPS (p<0·05). Cook yield of frozen stored mince increased with higher FAA but decreased with higher fat content, and the peak force of patties made from frozen stored mince was lowered by increased MS and low FC during storage. Various significant interactions are tabulated and discussed. 相似文献
208.
Phase behaviour,rheology and microstructure of mixture of meat proteins and kappa and iota carrageenans 总被引:2,自引:0,他引:2
The phase behaviour of mixtures of salt soluble meat proteins, kappa (κ) and iota (ι) carrageenan in non-gelling conditions (45 °C) were determined at pH 5.6, 6.2 and 7.1. The concentration of meat proteins ranged from 0.1 to 1.0 percent and that of κ-carrageenan and ι-carrageenan from 0.02 to 0.3 percent in the mixtures. Mixtures separated under gravity to form soluble/liquid and gelled/complex phases. For meat proteins- κ-carrageenan mixtures, phase separations at all meat protein/carrageenan ratios were observed. For meat protein-ι-carrageenan mixtures, soluble complexes were formed at low meat protein to ι-carrageenan ratios and gels at higher ratios. The yield of the complex/gels increased with the increase in the concentration of the meat proteins and carrageenans and decreased with increase in the pH of the initial mix. The complex/gels formed became stronger with the increase in carrageenan in the mix and with κ-carrageenan compared to ι-carrageenan. Chemical analyses and scanning electron and phase contrast microscopy indicated that in phase separated mixtures, the bulk of the meat proteins and carrageenan were found in the gel compared to the liquid phase; and that meat protein interacted with carrageenan in the gel and formed soluble complexes with carrageenan in the liquid phase. SDS-PAGE showed that the meat proteins that interacted to form the complex/gels with carrageenan included myosin heavy chain, α-actinin, actin, myosin light chains and proteins with molecular weights around 150 and 50 kD. The outcomes of the present study could be used in the formulation of multi-component foods with a range of consistencies containing meat proteins. 相似文献
209.
Organoclays assisted vat and disperse dyeing of poly(ethylene terephthalate) nanocomposite fabrics via melt spinning
下载免费PDF全文
![点击此处可从《Coloration Technology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Abdalla A. Mousa Yehya A. Youssef Wael S. Mohamed Reham Farouk Elisabeth Giebel Michael R. Buchmeiser 《Coloration Technology》2018,134(2):126-134
Polyethylene terephthalate nanocomposites containing six modified montmorillonite nanoclays were prepared by a melt compounding technique. The effect of intercalated compounds of montmorillonite on textile mechanical properties of resultant polyethylene terephthalate nanocomposite fabrics was investigated. Winding was not possible, when the polymers were first compounded with the desired amount of montmorillonite and then spun, as filament breakage occurred. Spinable polymer were only obtained by mixing polyethylene terephthalate master batches with 4 wt% montmorillonite, which contained tallow intercalating compound with pure untreated polyethylene terephthalate to a montmorillonite content of 0.5 wt%, thus decreasing the concentration of thermally degraded polymer chains. After spinning the fibres were drawn and knitted into fabric samples for further testing. The prepared polyethylene terephthalate nanocomposite fabrics using montmorillonite exhibited higher colour strength using vat and disperse dyes compared with those of the reference fabrics made from fibres spun without montmorillonite clay content and regular fabrics. The carbocyclic‐based vat dyes have higher colour strength values on polyethylene terephthalate nanocomposite fabrics if compared with heterocyclic‐based vat dyes. The colour fastness ratings for both vat and disperse dyeings secured very good to excellent washing and perspiration fastness on polyethylene terephthalate nanocomposite fabrics. All dyed fabrics showed excellent light fastness using vat and disperse dyes. The preparation of polyethylene terephthalate nanocomposite fabrics with improved textile mechanical and vat dyeing properties needs further investigations. 相似文献
210.
I Kashif H Farouk S.H Salah S.A Aly A.M Sanad A.M Hassan Rezk 《Materials Science and Engineering: B》1991,10(4):269-274
Electron spin resonance (ESR) and d.c. conductivity were measured for a series of vanadium borophosphate glasses before and after heat treatment. The ESR spectra showed the presence of vanadium in the V4+ state in all untreated and heat-treated samples free from iron. The variable temperature ESR and d.c. conductivity results obtained on the sample free from iron showed an inflexion at about 140°C. The electrical conductivity was found to decrease on substitution of 1 mol.% V2O5 by 1 mol.% Fe2O3 which may be due to a decrease in the V4+/V ratio. However, the electrical conductivity was found to increase on addition of more than 1 mol.% Fe2O3 which may be due to possible hopping conduction between Fe2+−Fe3+, V4+−Fe3+ and Fe2+−V5+. The increase in conductivity in the sample heat treated at 350°C relative to those heat treated at 300°C and 400°C may be due to the variation in the V4+/V total ratio. The activation energy values for untreated and heat-treated samples were calculated and were found to depend on the variation in the V4+/V ratio and the microstructure. 相似文献