全文获取类型
收费全文 | 100篇 |
免费 | 5篇 |
专业分类
化学工业 | 89篇 |
矿业工程 | 1篇 |
轻工业 | 2篇 |
无线电 | 3篇 |
一般工业技术 | 1篇 |
冶金工业 | 8篇 |
自动化技术 | 1篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2020年 | 2篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 7篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 3篇 |
2010年 | 5篇 |
2008年 | 3篇 |
2007年 | 3篇 |
2006年 | 1篇 |
2005年 | 5篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1976年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有105条查询结果,搜索用时 31 毫秒
1.
R. Gonzalez-Nunez B. D. Favis P. J. Carreau C. Lavalle 《Polymer Engineering and Science》1993,33(13):851-859
The morphology of the dispersed phase in immiscible polymer blends plays an important role in the determination of the final physical properties. This paper considers factors that influence the final state of deformation of the dispersed phase, and in particular, the formation of fibers and lamellae. Blends of polyethylene and nylon-6 were extruded by ribbon extrusion at different draw ratios. Prior to single-screw extrusion the materials were blended in a co-rotating twin-screw extruder, and the size of the dispersed phase was studied as a function of the viscosity ratio. As the blends are extruded into ribbons and drawn through the calender rolls, the morphology of the dispersed phase undergoes drastic transformations. The fiber formation is enhanced by increasing the draw ratio. At high draw ratios, long thin fibers are observed. Some biaxial deformation is obtained for the noncompatibilized systems when the extruded materials enter the calender with the maximum closing pressure applied to the rolls. The same effect is observed for the compatibilized systems with lower values of the viscosity ratio. As a general rule, it has been observed that the final dispersed phase deformation is diminished in interfacially compatibilized systems. 相似文献
2.
We have investigated the axial distribution of the liquid phase in a three-phase fluidized bed in which the particles were glass beads of two different diameters, 710-850 μm and 2 mm. Two methods were used to reduce the axial heterogeneity and homogenize the bed: the use of packing elements and the addition of a small quantity of a high molecular weight polymer. The use of packing elements was shown to be very efficient in controlling phases distribution in the bed. The packing consisted of 1 mm thick steel horizontal plates punched and stretched to obtain parallelogram-shaped openings. The addition of a high molecular weight polyisobutylene (BASF Oppanol B246, Mu, =6.15 Lo6) on the phase distribution was also studied. Low polymer concentrations up to 397 ppm (based on the liquid phase) were investigated. The addition of the polymer reduced bubble coalescence and allowed for a better distribution of the phases. 相似文献
3.
Mechanical properties of high density polyethylene (HDPE) extended to draw ratios in the 20–40 range have been determined and compared with corresponding properties of the polymers containing particulates including rutile, carbon black, iron oxide, and mica. Shrinkage of drawn structures was studied to temperatures near the fusion of the polymer host. The degree of interaction at polymer/additive interfaces was varied by surface coating certain of the solids with standard coupling agents. Solids were found to increase tensile moduli and to decrease shrinkage, particularly at higher exposure temperatures. The magnitude of changes due to the presence of solids was shown to depend on the apparent interaction at contacts between host and additive. In a dispersion–force matrix, like HDPE, benefits were optimized when the particulates were amphoteric or neutral, rather than having pronounced acid or base interaction potentials. 相似文献
4.
The liver microsomal Δ9 and Δ6 desaturase activities have been studied in rats with carbon tetrachloride-induced hepatitis. Immediately after poisoning,
significant decreases were observed for both types of desaturase activity. However, recovery kinetics were slower for the
Δ6 desaturase than for the Δ9 desaturase. The activities of NADH-ferricyanide and NADH-cytochrome C reductases, proteins involved in the electron transfers
associated with microsomal desaturation, were also measured. There was a fall in both activities after poisoning, but this
decrease was less than that of the desaturase activities. 相似文献
5.
An extensive experimental study of the effects of material characteristics and processing parameters on the kinematics and dynamics of film blowing is presented. Three polyethylene resins, a high-density polyethylene (HDPE), a low-density polyethylene (LDPE), and a linear low-density polyethylene (LLDPE) were investigated. The convergent flow analysis of Cogswell was used to characterize the elongational flow behavior of the polymers. Strain rates and pressure inside the bubble (Pi) have been determined over a wide range of film blowing conditions. Moreover, on-line bubble temperature and birefringence measurements have been carried out along the length of the bubble. The experimental results reveal that the three polymers display different behaviors. The LLDPE requires the highest Pi value and the LDPE, the lowest. Consistent with this, the LLDPE shows the lowest in-plane birefringence and the LDPE, the highest. Interactions between various process parameters affecting the Pi value are characterized. Bubble instability is correlated to the apparent uniaxial elongational viscosity and Pi. The most stable polymer (LDPE) has the highest elongational viscosity and requires the lowest Pi. Stresses have been calculated with the help of the birefringence and Pi data. The stress and strain rate data were used to calculate an apparent nonuniform biaxial elongational viscosity of the melts, but could not be correlated through any simple constitutive equation. 相似文献
6.
Ming-Cheng Guo Marie-Claude Heuzey Pierre J. Carreau 《Polymer Engineering and Science》2007,47(7):1070-1081
The cell structure and properties of branched and linear polypropylene (PP) foams containing organically modified nanoclay and maleic anhydride grafted polypropylene (PPMA) have been thoroughly investigated. X-ray diffraction (XRD) and melt rheometry were used to identify the structure and linear viscoelastic properties of the nanocomposites, as well as the effectiveness of two different compatibilizers. These nanocomposites were used in injection molding to investigate their foamability and the influence of experimental conditions such as chemical foaming agent concentration, shot size, back pressure, injection speed, as well as melt temperature and different injection methods on the resulting cell structure of the foams. Quite different results were obtained with the linear and the branched PP. While the foamability of the branched PP was intrinsically good, that of the linear one could largely be improved by modifying its rheological properties and favoring nucleation through the addition of nanoclay. The effect of cell structure on the dynamic mechanical properties of the foams was also investigated using dynamic mechanical analysis (DMA). POLYM. ENG. SCI., 47:1070–1081, 2007. © 2007 Society of Plastics Engineers 相似文献
7.
The effects of the non-Newtonian properties on the effective deformation rate, mixing and circulation times and flow behaviour have been investigated in the transition flow regime of mixing systems. Based on the equivalent Couette flow, three models are proposed and are shown to predict similar and drastic increases of the effective deformation rate with the impeller rotational speed in the transition regime. The predictions are shown to fit very well data obtained for various non-Newtonian fluids mixed with helical ribbon agitators, and with literature data for anchor, blade turbine and flat disc agitators. The elasticity along with shear-thinning properties appear to have slight effects on the dimensionless mixing and circulation times in the transition regime, whereas their effects in the laminar regime are quite drastic, as reported by others. 相似文献
8.
Hesam Ghasemi Pierre J. Carreau Musa R. Kamal Seyed H. Tabatabaei 《Polymer Engineering and Science》2012,52(2):420-430
Polyethylene terephthalate (PET) nanocomposite films were prepared by cast extrusion followed by uniaxial stretching, using chill rolls. Transmission electron microscopy (TEM) and wide angle X‐ray diffraction (WAXD) showed that the clay layers were aligned in the machine direction (MD) in the PET/clay nanocomposite (PCN) films. Differential scanning calorimetry (DSC) showed that PCN films have higher crystallinity than the neat PET films, possibly due to the nucleating role of the silicate layers. The PCN films became hazier as the clay content increased, but the film transparency remained in the acceptable range. Oxygen permeability of the PCN films decreased by 23% compared to the neat PET film. This is comparable with predictions of models proposed in the literature. Silicate incorporation brought about 20% increase in the tensile modulus, while the puncture and tear propagation resistance were reduced, due to brittleness of the PCN films. The measured modulus (1.7 GPa) was somewhat smaller than the values predicted using the Pseudoinclusion model (2.1 GPa). POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers 相似文献
9.
Seyed H. Tabatabaei Pierre J. Carreau Abdellah Ajji 《Polymer Engineering and Science》2010,50(1):191-199
Blends of a long‐chain branched polypropylene (LCB‐PP) and a linear polypropylene (L‐PP) were prepared using a twin‐screw extruder. Linear viscoelastic properties such as complex viscosity, storage modulus, and weighted relaxation spectrum were determined as functions of LCB‐PP content. Shear data obtained from commercial rheometers as well as from a slit‐die rheometer were used to verify the Cox‐Merz relation for the neat components as well as for a blend. Elongational properties were obtained using a Sentmanat Extensional Rheometer (SER) unit mounted on an Advanced Rheometric Expansion System (ARES) rheometer and the converging die. A significant strain hardening was observed for the neat LCB‐PP as well as for all the blends, but the strain hardening decreased with increasing strain rate. The apparent steady elongational viscosity values evaluated using the converging die were observed to be comparable at high deformation rates to those obtained from the SER unit, but the differences increased as the strain rate decreased. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers 相似文献
10.
Stefan Brandstetter Vincent Carreau Sylvain Maîtrejean Marc Legros 《Microelectronic Engineering》2010,87(3):383-386
The evolution of the grain structure through annealing of narrow damascene Cu interconnects is important for any further design of highly integrated circuits. Here we present a comprehensive transmission electron microscopy study of damascene lines between 80 nm and 3000 nm wide. Experimental results clearly indicate that morphology evolutions through annealing are strongly influenced by the line width. If the lines are wider than 250 nm a strong connection between the grain structure within the lines and the overburden copper is present at least after sufficient annealing. Once the lines are as small as 80 nm the grain structure within the lines are only weakly connected to the overburden copper grown above. 相似文献